[PATCH v3 1/3] mtd: spi-nor: introduce SR_BP_SHIFT define

[PATCH v3 1/3] mtd: spi-nor: introduce SR_BP_SHIFT define

[Jungseung Lee]

The shift variable of SR_BP is conclusive because the first bit of SR_BP
is fixed on all known flashes.

Introduce SR_BP_SHIFT define and let them used by stm_* functions
to replace ffs operation to get shift value.

Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 11 +++++------
 include/linux/mtd/spi-nor.h   |  2 ++
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index addb6319fcbb..e3da6a8654a8 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -1767,7 +1767,6 @@ static void stm_get_locked_range(struct spi_nor *nor, u8 sr, loff_t *ofs,
 	struct mtd_info *mtd = &nor->mtd;
 	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
 	u8 tb_mask = SR_TB_BIT5;
-	int shift = ffs(mask) - 1;
 	int pow;
 
 	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
@@ -1778,7 +1777,7 @@ static void stm_get_locked_range(struct spi_nor *nor, u8 sr, loff_t *ofs,
 		*ofs = 0;
 		*len = 0;
 	} else {
-		pow = ((sr & mask) ^ mask) >> shift;
+		pow = ((sr & mask) ^ mask) >> SR_BP_SHIFT;
 		*len = mtd->size >> pow;
 		if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
 			*ofs = 0;
@@ -1860,7 +1859,7 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 	int ret, status_old, status_new;
 	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
 	u8 tb_mask = SR_TB_BIT5;
-	u8 shift = ffs(mask) - 1, pow, val;
+	u8 pow, val;
 	loff_t lock_len;
 	bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
 	bool use_top;
@@ -1909,7 +1908,7 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 	 *   pow = ceil(log2(size / len)) = log2(size) - floor(log2(len))
 	 */
 	pow = ilog2(mtd->size) - ilog2(lock_len);
-	val = mask - (pow << shift);
+	val = mask - (pow << SR_BP_SHIFT);
 	if (val & ~mask)
 		return -EINVAL;
 	/* Don't "lock" with no region! */
@@ -1946,7 +1945,7 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 	int ret, status_old, status_new;
 	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
 	u8 tb_mask = SR_TB_BIT5;
-	u8 shift = ffs(mask) - 1, pow, val;
+	u8 pow, val;
 	loff_t lock_len;
 	bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
 	bool use_top;
@@ -1997,7 +1996,7 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 	if (lock_len == 0) {
 		val = 0; /* fully unlocked */
 	} else {
-		val = mask - (pow << shift);
+		val = mask - (pow << SR_BP_SHIFT);
 		/* Some power-of-two sizes are not supported */
 		if (val & ~mask)
 			return -EINVAL;
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 7e32adce72f7..541c06d042e8 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -137,6 +137,8 @@
 
 #define SR1_QUAD_EN_BIT6	BIT(6)
 
+#define SR_BP_SHIFT		2
+
 /* Enhanced Volatile Configuration Register bits */
 #define EVCR_QUAD_EN_MICRON	BIT(7)	/* Micron Quad I/O */
 
-- 
2.17.1


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[PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Currently, we are supporting block protection only for
flash chips with 3 block protection bits in the SR register.
This patch enables block protection support for some flash with
4 block protection bits(bp0-3).

Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
---
v3 :
  Fix wrong ofs calculation on v2 patch
v2 :
  Add sample table portion about 4bit block protection on the comment
  Trivial coding style change

 drivers/mtd/spi-nor/spi-nor.c | 127 +++++++++++++++++++++++++++++-----
 include/linux/mtd/spi-nor.h   |   8 +++
 2 files changed, 119 insertions(+), 16 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index e3da6a8654a8..7e8af6c4fdfa 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -238,6 +238,14 @@ struct flash_info {
 					 * status register. Must be used with
 					 * SPI_NOR_HAS_TB.
 					 */
+#define SPI_NOR_HAS_BP3		BIT(17)	/*
+					 * Flash SR has 4 bit fields (BP0-3)
+					 * for block protection.
+					 */
+#define SPI_NOR_BP3_SR_BIT6	BIT(18)	/*
+					 * BP3 is bit 6 of status register.
+					 * Must be used with SPI_NOR_HAS_BP3.
+					 */
 
 	/* Part specific fixup hooks. */
 	const struct spi_nor_fixups *fixups;
@@ -1767,23 +1775,47 @@ static void stm_get_locked_range(struct spi_nor *nor, u8 sr, loff_t *ofs,
 	struct mtd_info *mtd = &nor->mtd;
 	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
 	u8 tb_mask = SR_TB_BIT5;
-	int pow;
+	u8 bp;
+	int pow = 0;
 
 	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
 		tb_mask = SR_TB_BIT6;
 
-	if (!(sr & mask)) {
-		/* No protection */
-		*ofs = 0;
-		*len = 0;
+	if (nor->flags & SNOR_F_HAS_SR_BP3) {
+		u8 tmp;
+
+		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
+			tmp = sr & (mask | SR_BP3_BIT6);
+		else
+			tmp = sr & (mask | SR_BP3_BIT5);
+
+		if (tmp & SR_BP3_BIT6)
+			tmp = (tmp & ~BIT(6)) | BIT(5);
+
+		bp = tmp >> SR_BP_SHIFT;
+		if (!bp) {
+			*ofs = 0;
+			*len = 0;
+			return;
+		}
+		if (bp <= ilog2(nor->n_sectors))
+			pow = ilog2(nor->n_sectors) + 1 - bp;
 	} else {
-		pow = ((sr & mask) ^ mask) >> SR_BP_SHIFT;
-		*len = mtd->size >> pow;
-		if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
+		bp = (sr & mask) >> SR_BP_SHIFT;
+		if (!bp) {
 			*ofs = 0;
-		else
-			*ofs = mtd->size - *len;
+			*len = 0;
+			return;
+		}
+		pow = bp ^ (mask >> SR_BP_SHIFT);
 	}
+
+	*len = mtd->size >> pow;
+
+	if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
+		*ofs = 0;
+	else
+		*ofs = mtd->size - *len;
 }
 
 /*
@@ -1823,7 +1855,7 @@ static int stm_is_unlocked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
 
 /*
  * Lock a region of the flash. Compatible with ST Micro and similar flash.
- * Supports the block protection bits BP{0,1,2} in the status register
+ * Supports the block protection bits BP{0,1,2,3} in the status register
  * (SR). Does not support these features found in newer SR bitfields:
  *   - SEC: sector/block protect - only handle SEC=0 (block protect)
  *   - CMP: complement protect - only support CMP=0 (range is not complemented)
@@ -1831,7 +1863,7 @@ static int stm_is_unlocked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
  * Support for the following is provided conditionally for some flash:
  *   - TB: top/bottom protect
  *
- * Sample table portion for 8MB flash (Winbond w25q64fw):
+ * Sample table portion for 8MB flash (Winbond w25q64fw / BP0-2):
  *
  *   SEC  |  TB   |  BP2  |  BP1  |  BP0  |  Prot Length  | Protected Portion
  *  --------------------------------------------------------------------------
@@ -1851,6 +1883,32 @@ static int stm_is_unlocked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
  *    0   |   1   |   1   |   0   |   1   |  2 MB         | Lower 1/4
  *    0   |   1   |   1   |   1   |   0   |  4 MB         | Lower 1/2
  *
+ * Sample table portion for 64MB flash (Micron n25q512ax3 / BP0-3):
+ *
+ *   TB   |  BP3  |  BP2  |  BP1  |  BP0  |  Prot Length  | Protected Portion
+ *  --------------------------------------------------------------------------
+ *    0   |   0   |   0   |   0   |   0   |  NONE         | NONE
+ *    0   |   0   |   0   |   0   |   1   |   64 KB       | Upper 1/1024
+ *    0   |   0   |   0   |   1   |   0   |  128 KB       | Upper 1/512
+ *    0   |   0   |   0   |   1   |   1   |  256 KB       | Upper 1/256
+ *   ...
+ *    0   |   1   |   0   |   0   |   1   |  16 MB        | Upper 1/4
+ *    0   |   1   |   0   |   1   |   0   |  32 MB        | Upper 1/2
+ *    0   |   1   |   0   |   1   |   1   |  64 MB        | ALL
+ *    0   |   1   |   1   |   0   |   0   |  64 MB        | ALL
+ *   ...
+ *  ------|-------|-------|-------|-------|---------------|-------------------
+ *    1   |   0   |   0   |   0   |   0   |   NONE        | NONE
+ *    1   |   0   |   0   |   0   |   1   |   64 KB       | Lower 1/1024
+ *    1   |   0   |   0   |   1   |   0   |  128 KB       | Lower 1/512
+ *    1   |   0   |   0   |   1   |   1   |  256 KB       | Lower 1/256
+ *   ...
+ *    1   |   1   |   0   |   0   |   1   |  16 MB        | Lower 1/4
+ *    1   |   1   |   0   |   1   |   0   |  32 MB        | Lower 1/2
+ *    1   |   1   |   0   |   1   |   1   |  64 MB        | ALL
+ *    1   |   1   |   1   |   0   |   0   |  64 MB        | ALL
+ *   ...
+ *
  * Returns negative on errors, 0 on success.
  */
 static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
@@ -1898,6 +1956,12 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
 		tb_mask = SR_TB_BIT6;
 
+	if (nor->flags & SNOR_F_HAS_SR_BP3) {
+		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
+			mask = mask | SR_BP3_BIT6;
+		else
+			mask = mask | SR_BP3_BIT5;
+	}
 	/*
 	 * Need smallest pow such that:
 	 *
@@ -1908,7 +1972,17 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 	 *   pow = ceil(log2(size / len)) = log2(size) - floor(log2(len))
 	 */
 	pow = ilog2(mtd->size) - ilog2(lock_len);
-	val = mask - (pow << SR_BP_SHIFT);
+
+	if (nor->flags & SNOR_F_HAS_SR_BP3) {
+		val = ilog2(nor->n_sectors) + 1 - pow;
+		val = val << SR_BP_SHIFT;
+
+		if (val & BIT(5) && mask & SR_BP3_BIT6)
+			val = (val & ~BIT(5)) | BIT(6);
+	} else {
+		val = mask - (pow << SR_BP_SHIFT);
+	}
+
 	if (val & ~mask)
 		return -EINVAL;
 	/* Don't "lock" with no region! */
@@ -1983,6 +2057,13 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 
 	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
 		tb_mask = SR_TB_BIT6;
+
+	if (nor->flags & SNOR_F_HAS_SR_BP3) {
+		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
+			mask = mask | SR_BP3_BIT6;
+		else
+			mask = mask | SR_BP3_BIT5;
+	}
 	/*
 	 * Need largest pow such that:
 	 *
@@ -1995,13 +2076,20 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 	pow = ilog2(mtd->size) - order_base_2(lock_len);
 	if (lock_len == 0) {
 		val = 0; /* fully unlocked */
+	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
+		val = ilog2(nor->n_sectors) + 1 - pow;
+		val = val << SR_BP_SHIFT;
+
+		if (val & BIT(5) && mask & SR_BP3_BIT6)
+			val = (val & ~BIT(5)) | BIT(6);
 	} else {
 		val = mask - (pow << SR_BP_SHIFT);
-		/* Some power-of-two sizes are not supported */
-		if (val & ~mask)
-			return -EINVAL;
 	}
 
+	/* Some power-of-two sizes are not supported */
+	if (val & ~mask)
+		return -EINVAL;
+
 	status_new = (status_old & ~mask & ~tb_mask) | val;
 
 	/* Don't protect status register if we're fully unlocked */
@@ -4736,6 +4824,7 @@ static void spi_nor_info_init_params(struct spi_nor *nor)
 	/* Set SPI NOR sizes. */
 	params->size = (u64)info->sector_size * info->n_sectors;
 	params->page_size = info->page_size;
+	params->n_sectors = info->n_sectors;
 
 	if (!(info->flags & SPI_NOR_NO_FR)) {
 		/* Default to Fast Read for DT and non-DT platform devices. */
@@ -5192,6 +5281,11 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
 		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
 	if (info->flags & USE_CLSR)
 		nor->flags |= SNOR_F_USE_CLSR;
+	if (info->flags & SPI_NOR_HAS_BP3) {
+		nor->flags |= SNOR_F_HAS_SR_BP3;
+		if (info->flags & SPI_NOR_BP3_SR_BIT6)
+			nor->flags |= SNOR_F_HAS_SR_BP3_BIT6;
+	}
 
 	if (info->flags & SPI_NOR_NO_ERASE)
 		mtd->flags |= MTD_NO_ERASE;
@@ -5199,6 +5293,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
 	mtd->dev.parent = dev;
 	nor->page_size = params->page_size;
 	mtd->writebufsize = nor->page_size;
+	nor->n_sectors = params->n_sectors;
 
 	if (of_property_read_bool(np, "broken-flash-reset"))
 		nor->flags |= SNOR_F_BROKEN_RESET;
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 541c06d042e8..92d550501daf 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -129,7 +129,9 @@
 #define SR_BP1			BIT(3)	/* Block protect 1 */
 #define SR_BP2			BIT(4)	/* Block protect 2 */
 #define SR_TB_BIT5		BIT(5)	/* Top/Bottom protect */
+#define SR_BP3_BIT5		BIT(5)	/* Block protect 3 */
 #define SR_TB_BIT6		BIT(6)	/* Top/Bottom protect */
+#define SR_BP3_BIT6		BIT(6)	/* Block protect 3 */
 #define SR_SRWD			BIT(7)	/* SR write protect */
 /* Spansion/Cypress specific status bits */
 #define SR_E_ERR		BIT(5)
@@ -248,6 +250,8 @@ enum spi_nor_option_flags {
 	SNOR_F_HAS_16BIT_SR	= BIT(9),
 	SNOR_F_NO_READ_CR	= BIT(10),
 	SNOR_F_HAS_SR_TB_BIT6	= BIT(11),
+	SNOR_F_HAS_SR_BP3	= BIT(12),
+	SNOR_F_HAS_SR_BP3_BIT6	= BIT(13),
 
 };
 
@@ -519,6 +523,7 @@ struct spi_nor_locking_ops {
  *
  * @size:		the flash memory density in bytes.
  * @page_size:		the page size of the SPI NOR flash memory.
+ * @n_sectors:		number of sectors
  * @hwcaps:		describes the read and page program hardware
  *			capabilities.
  * @reads:		read capabilities ordered by priority: the higher index
@@ -541,6 +546,7 @@ struct spi_nor_locking_ops {
 struct spi_nor_flash_parameter {
 	u64				size;
 	u32				page_size;
+	u16				n_sectors;
 
 	struct spi_nor_hwcaps		hwcaps;
 	struct spi_nor_read_command	reads[SNOR_CMD_READ_MAX];
@@ -573,6 +579,7 @@ struct flash_info;
  * @bouncebuf_size:	size of the bounce buffer
  * @info:		spi-nor part JDEC MFR id and other info
  * @page_size:		the page size of the SPI NOR
+ * @n_sector:		number of sectors
  * @addr_width:		number of address bytes
  * @erase_opcode:	the opcode for erasing a sector
  * @read_opcode:	the read opcode
@@ -599,6 +606,7 @@ struct spi_nor {
 	size_t			bouncebuf_size;
 	const struct flash_info	*info;
 	u32			page_size;
+	u16			n_sectors;
 	u8			addr_width;
 	u8			erase_opcode;
 	u8			read_opcode;
-- 
2.17.1


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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Tudor.Ambarus]

Hi, Jungseung,

Thanks for working on this.

On Monday, January 13, 2020 7:59:06 AM EET Jungseung Lee wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the
> content is safe
> 
> Currently, we are supporting block protection only for
> flash chips with 3 block protection bits in the SR register.
> This patch enables block protection support for some flash with
> 4 block protection bits(bp0-3).

Some? Isn't this generic for all the flashes that support BP0-3?

> 
> Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> ---
> v3 :
>   Fix wrong ofs calculation on v2 patch
> v2 :
>   Add sample table portion about 4bit block protection on the comment
>   Trivial coding style change
> 
>  drivers/mtd/spi-nor/spi-nor.c | 127 +++++++++++++++++++++++++++++-----
>  include/linux/mtd/spi-nor.h   |   8 +++
>  2 files changed, 119 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index e3da6a8654a8..7e8af6c4fdfa 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -238,6 +238,14 @@ struct flash_info {
>                                          * status register. Must be used
> with * SPI_NOR_HAS_TB.
>                                          */
> +#define SPI_NOR_HAS_BP3                BIT(17) /*
> +                                        * Flash SR has 4 bit fields (BP0-3)
> +                                        * for block protection.
> +                                        */
> +#define SPI_NOR_BP3_SR_BIT6    BIT(18) /*
> +                                        * BP3 is bit 6 of status register.
> +                                        * Must be used with

Are we safe to replace SPI_NOR_TB_SR_BIT6 and SPI_NOR_BP3_SR_BIT6 with a 
SPI_NOR_SR_TB_BIT6_BP3_BIT5? Or maybe with a SPI_NOR_SR_BP3_BIT6_TB_BIT5, how 
is more convenient?

Cheers,
ta


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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Hi, Tudor,

On Tue, Jan 14, 2020 at 7:49 PM <Tudor.Ambarus@microchip.com> wrote:
>
> Hi, Jungseung,
>
> Thanks for working on this.
>
> On Monday, January 13, 2020 7:59:06 AM EET Jungseung Lee wrote:
> > EXTERNAL EMAIL: Do not click links or open attachments unless you know the
> > content is safe
> >
> > Currently, we are supporting block protection only for
> > flash chips with 3 block protection bits in the SR register.
> > This patch enables block protection support for some flash with
> > 4 block protection bits(bp0-3).
>
> Some? Isn't this generic for all the flashes that support BP0-3?
>

This one would be a generic solution to support BP0-3 on Status Register.
From my study, this covers all the flashes listed on spi-nor.c that
have BP0-3 bit on SR.
It looks like I have to change this description.

Note that it is NOT for some flashes that have BP0-3 in another register.
As you know, just like SPI_NOR_HAS_TB did.

> >
> > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> > ---
> > v3 :
> >   Fix wrong ofs calculation on v2 patch
> > v2 :
> >   Add sample table portion about 4bit block protection on the comment
> >   Trivial coding style change
> >
> >  drivers/mtd/spi-nor/spi-nor.c | 127 +++++++++++++++++++++++++++++-----
> >  include/linux/mtd/spi-nor.h   |   8 +++
> >  2 files changed, 119 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> > index e3da6a8654a8..7e8af6c4fdfa 100644
> > --- a/drivers/mtd/spi-nor/spi-nor.c
> > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > @@ -238,6 +238,14 @@ struct flash_info {
> >                                          * status register. Must be used
> > with * SPI_NOR_HAS_TB.
> >                                          */
> > +#define SPI_NOR_HAS_BP3                BIT(17) /*
> > +                                        * Flash SR has 4 bit fields (BP0-3)
> > +                                        * for block protection.
> > +                                        */
> > +#define SPI_NOR_BP3_SR_BIT6    BIT(18) /*
> > +                                        * BP3 is bit 6 of status register.
> > +                                        * Must be used with
>
> Are we safe to replace SPI_NOR_TB_SR_BIT6 and SPI_NOR_BP3_SR_BIT6 with a
> SPI_NOR_SR_TB_BIT6_BP3_BIT5? Or maybe with a SPI_NOR_SR_BP3_BIT6_TB_BIT5, how
> is more convenient?
>

Let's think about some flash in which BP0-3 exists in the status
register but TB exists in another register.
for example, mx25u12835f.
I haven't tested yet, but according to the datasheet, I think this
patch can support 4bit block protection for the flash.

In order to embrace the case, how about letting them as It is.
Is there any suggestion?

> Cheers,
> ta
>

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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Hi, Tudor,

2020-01-18 (Sat), 00:06 +0900, Jungseung Lee:
> Hi, Tudor,
> 
> On Tue, Jan 14, 2020 at 7:49 PM <Tudor.Ambarus@microchip.com> wrote:
> > 
> > Hi, Jungseung,
> > 
> > Thanks for working on this.
> > 
> > On Monday, January 13, 2020 7:59:06 AM EET Jungseung Lee wrote:
> > > EXTERNAL EMAIL: Do not click links or open attachments unless you
> > > know the
> > > content is safe
> > > 
> > > Currently, we are supporting block protection only for
> > > flash chips with 3 block protection bits in the SR register.
> > > This patch enables block protection support for some flash with
> > > 4 block protection bits(bp0-3).
> > 
> > Some? Isn't this generic for all the flashes that support BP0-3?
> > 
> 
> This one would be a generic solution to support BP0-3 on Status
> Register.
> From my study, this covers all the flashes listed on spi-nor.c that
> have BP0-3 bit on SR.
> It looks like I have to change this description.
> 
> Note that it is NOT for some flashes that have BP0-3 in another
> register.
> As you know, just like SPI_NOR_HAS_TB did.
> 
> > > 
> > > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> > > ---
> > > v3 :
> > >   Fix wrong ofs calculation on v2 patch
> > > v2 :
> > >   Add sample table portion about 4bit block protection on the
> > > comment
> > >   Trivial coding style change
> > > 
> > >  drivers/mtd/spi-nor/spi-nor.c | 127
> > > +++++++++++++++++++++++++++++-----
> > >  include/linux/mtd/spi-nor.h   |   8 +++
> > >  2 files changed, 119 insertions(+), 16 deletions(-)
> > > 
> > > diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-
> > > nor/spi-nor.c
> > > index e3da6a8654a8..7e8af6c4fdfa 100644
> > > --- a/drivers/mtd/spi-nor/spi-nor.c
> > > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > > @@ -238,6 +238,14 @@ struct flash_info {
> > >                                          * status register. Must
> > > be used
> > > with * SPI_NOR_HAS_TB.
> > >                                          */
> > > +#define SPI_NOR_HAS_BP3                BIT(17) /*
> > > +                                        * Flash SR has 4 bit
> > > fields (BP0-3)
> > > +                                        * for block protection.
> > > +                                        */
> > > +#define SPI_NOR_BP3_SR_BIT6    BIT(18) /*
> > > +                                        * BP3 is bit 6 of status
> > > register.
> > > +                                        * Must be used with
> > 
> > Are we safe to replace SPI_NOR_TB_SR_BIT6 and SPI_NOR_BP3_SR_BIT6
> > with a
> > SPI_NOR_SR_TB_BIT6_BP3_BIT5? Or maybe with a
> > SPI_NOR_SR_BP3_BIT6_TB_BIT5, how
> > is more convenient?
> > 
> 
> Let's think about some flash in which BP0-3 exists in the status
> register but TB exists in another register.
> for example, mx25u12835f.
> I haven't tested yet, but according to the datasheet, I think this
> patch can support 4bit block protection for the flash.
> 
> In order to embrace the case, how about letting them as It is.
> Is there any suggestion?
> 

Hmm.. I again have summarized the case of using 4bit block protection.

* Not supporting TB on status register.

- BP3(BIT5)
  SPI_NOR_HAS_BP3

- BP3(BIT6)
  SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6

* Supporting TB on status register.

- TB(BIT6), BP3(BIT5)
  SPI_NOR_HAS_TB | SPI_NOR_TB_SR_BIT6 | SPI_NOR_HAS_BP3
  vs
  SPI_NOR_HAS_TB | SPI_NOR_HAS_BP3 | SPI_NOR_SR_TB_BIT6_BP3_BIT5
    
- TB(BIT5), BP3(BIT6)
  SPI_NOR_HAS_TB | SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6
  vs
  SPI_NOR_HAS_TB | SPI_NOR_HAS_BP3 | SPI_NOR_SR_TB_BIT5_BP3_BIT6  
    
SPI_NOR_BP3_SR_BIT6 and SPI_NOR_TB_SR_BIT6 must exist becuase it maybe
used. It would be ok to add some definitions(as you mentioned) to get
same value with SPI_NOR_BP3_SR_BIT6 or SPI_NOR_TB_SR_BIT6 for
readabilty.

But I think there is nothing looks so cool. Any suggestion?

> > Cheers,
> > ta
> > 
> 
> 
Thanks,
Jungseung Lee


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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Tudor.Ambarus]

Hi, Jungseung,

On Wednesday, January 22, 2020 1:42:00 PM EET Jungseung Lee wrote:

cut

> > > > +#define SPI_NOR_BP3_SR_BIT6    BIT(18) /*
> > > > +                                        * BP3 is bit 6 of status
> > > > register.
> > > > +                                        * Must be used with
> > > 
> > > Are we safe to replace SPI_NOR_TB_SR_BIT6 and SPI_NOR_BP3_SR_BIT6
> > > with a
> > > SPI_NOR_SR_TB_BIT6_BP3_BIT5? Or maybe with a
> > > SPI_NOR_SR_BP3_BIT6_TB_BIT5, how
> > > is more convenient?
> > 
> > Let's think about some flash in which BP0-3 exists in the status
> > register but TB exists in another register.
> > for example, mx25u12835f.
> > I haven't tested yet, but according to the datasheet, I think this
> > patch can support 4bit block protection for the flash.
> > 
> > In order to embrace the case, how about letting them as It is.
> > Is there any suggestion?

Ok, this info should go in the commit message, together with details about 
which flashes were tested.

I didn't know that the TB bit can be defined in the Configuration register. 
This means that your suggestion with dedicated macros for BP3 and TB is fine.

I looked a bit over your patches, they are in a pretty good shape. I saw 
something that can be improved on patch 2/3, but I didn't manage to finish the 
review. Your patches are the first on my TODO list, but now I'm a bit busy. I 
hope that I'll come with a complete review by the end of the next week. I'm 
going to do tests on few flashes too, to make sure that BP0-2 was not 
affected.

In the meantime, maybe Michael or John can review/test your patches, they 
showed interest in BP0-3 support.

Cheers,
ta


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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Am 2020-01-22 15:31, schrieb Tudor.Ambarus@microchip.com:
> Hi, Jungseung,
> 
> On Wednesday, January 22, 2020 1:42:00 PM EET Jungseung Lee wrote:
> 
> cut
> 
>> > > > +#define SPI_NOR_BP3_SR_BIT6    BIT(18) /*
>> > > > +                                        * BP3 is bit 6 of status
>> > > > register.
>> > > > +                                        * Must be used with
>> > >
>> > > Are we safe to replace SPI_NOR_TB_SR_BIT6 and SPI_NOR_BP3_SR_BIT6
>> > > with a
>> > > SPI_NOR_SR_TB_BIT6_BP3_BIT5? Or maybe with a
>> > > SPI_NOR_SR_BP3_BIT6_TB_BIT5, how
>> > > is more convenient?
>> >
>> > Let's think about some flash in which BP0-3 exists in the status
>> > register but TB exists in another register.
>> > for example, mx25u12835f.

And like the mx25u3232f, but this bit is only OTP programmable! For now,
I'd only add support for reading the TB bit to for this kind of flashes,
to prevent accidentially program this bit. It would be up to the board
manufacturer how to actually set the bit.

Like having a TB_READ_ONLY flag.

Its also some kind of asymmetrical because you can only set it one way,
eg. you can OTP the flash to be TB=1. Then you can be sure that the 
flash
will always be TB=1. But OTOH you cannot be sure that a TB=0 flash will
always be a TB=0 flash, because you cannot lock that bit.

Any thoughts?

-michael

>> > I haven't tested yet, but according to the datasheet, I think this
>> > patch can support 4bit block protection for the flash.
>> >
>> > In order to embrace the case, how about letting them as It is.
>> > Is there any suggestion?
> 
> Ok, this info should go in the commit message, together with details 
> about
> which flashes were tested.
> 
> I didn't know that the TB bit can be defined in the Configuration 
> register.
> This means that your suggestion with dedicated macros for BP3 and TB is 
> fine.
> 
> I looked a bit over your patches, they are in a pretty good shape. I 
> saw
> something that can be improved on patch 2/3, but I didn't manage to 
> finish the
> review. Your patches are the first on my TODO list, but now I'm a bit 
> busy. I
> hope that I'll come with a complete review by the end of the next week. 
> I'm
> going to do tests on few flashes too, to make sure that BP0-2 was not
> affected.
> 
> In the meantime, maybe Michael or John can review/test your patches, 
> they
> showed interest in BP0-3 support.
> 
> Cheers,
> ta

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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Hi, Michael

2020-01-22 (Wed), 18:14 +0100, Michael Walle:
> Am 2020-01-22 15:31, schrieb Tudor.Ambarus@microchip.com:
> > Hi, Jungseung,
> > 
> > On Wednesday, January 22, 2020 1:42:00 PM EET Jungseung Lee wrote:
> > 
> > cut
> > 
> > > > > > +#define SPI_NOR_BP3_SR_BIT6    BIT(18) /*
> > > > > > +                                        * BP3 is bit 6 of
> > > > > > status
> > > > > > register.
> > > > > > +                                        * Must be used
> > > > > > with
> > > > > 
> > > > > Are we safe to replace SPI_NOR_TB_SR_BIT6 and
> > > > > SPI_NOR_BP3_SR_BIT6
> > > > > with a
> > > > > SPI_NOR_SR_TB_BIT6_BP3_BIT5? Or maybe with a
> > > > > SPI_NOR_SR_BP3_BIT6_TB_BIT5, how
> > > > > is more convenient?
> > > > 
> > > > Let's think about some flash in which BP0-3 exists in the
> > > > status
> > > > register but TB exists in another register.
> > > > for example, mx25u12835f.
> 
> And like the mx25u3232f, but this bit is only OTP programmable! For
> now,
> I'd only add support for reading the TB bit to for this kind of
> flashes,
> to prevent accidentially program this bit. It would be up to the
> board
> manufacturer how to actually set the bit.
> 
> Like having a TB_READ_ONLY flag.
> 
> Its also some kind of asymmetrical because you can only set it one
> way,
> eg. you can OTP the flash to be TB=1. Then you can be sure that the 
> flash
> will always be TB=1. But OTOH you cannot be sure that a TB=0 flash
> will
> always be a TB=0 flash, because you cannot lock that bit.
> 
> Any thoughts?
> 

Actually, I didn't get the chance to take a look at some flash that has
TB bit in configuration register. Currently mainline kernel just care
flashes that has TB bit in SR and SPI_NOR_HAS_TB can be set only such
flashes(as you could see in comment). It seems neccessary to add
another functions and flag for mx25u3232f case.
Is there any flash that has OTP programmable TB bit in SR?

Tudor and me were saying that there is some flash that has not TB bit
in *SR* even if it has BP3 bit in SR. So it seems unnecessary to make
correlated flag like SPI_NOR_SR_TB_BIT6_BP3_BIT5 for convenience.

> -michael
> 
> > > > I haven't tested yet, but according to the datasheet, I think
> > > > this
> > > > patch can support 4bit block protection for the flash.
> > > > 
> > > > In order to embrace the case, how about letting them as It is.
> > > > Is there any suggestion?
> > 
> > Ok, this info should go in the commit message, together with
> > details 
> > about
> > which flashes were tested.
> > 
> > I didn't know that the TB bit can be defined in the Configuration 
> > register.
> > This means that your suggestion with dedicated macros for BP3 and
> > TB is 
> > fine.
> > 
> > I looked a bit over your patches, they are in a pretty good shape.
> > I 
> > saw
> > something that can be improved on patch 2/3, but I didn't manage
> > to 
> > finish the
> > review. Your patches are the first on my TODO list, but now I'm a
> > bit 
> > busy. I
> > hope that I'll come with a complete review by the end of the next
> > week. 
> > I'm
> > going to do tests on few flashes too, to make sure that BP0-2 was
> > not
> > affected.
> > 
> > In the meantime, maybe Michael or John can review/test your
> > patches, 
> > they
> > showed interest in BP0-3 support.
> > 
> > Cheers,
> > ta
> 
> 
Thanks,
Jungseung Lee


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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Am 2020-01-23 04:59, schrieb Jungseung Lee:
> Hi, Michael
> 
> 2020-01-22 (Wed), 18:14 +0100, Michael Walle:
>> Am 2020-01-22 15:31, schrieb Tudor.Ambarus@microchip.com:
>> > Hi, Jungseung,
>> >
>> > On Wednesday, January 22, 2020 1:42:00 PM EET Jungseung Lee wrote:
>> >
>> > cut
>> >
>> > > > > > +#define SPI_NOR_BP3_SR_BIT6    BIT(18) /*
>> > > > > > +                                        * BP3 is bit 6 of
>> > > > > > status
>> > > > > > register.
>> > > > > > +                                        * Must be used
>> > > > > > with
>> > > > >
>> > > > > Are we safe to replace SPI_NOR_TB_SR_BIT6 and
>> > > > > SPI_NOR_BP3_SR_BIT6
>> > > > > with a
>> > > > > SPI_NOR_SR_TB_BIT6_BP3_BIT5? Or maybe with a
>> > > > > SPI_NOR_SR_BP3_BIT6_TB_BIT5, how
>> > > > > is more convenient?
>> > > >
>> > > > Let's think about some flash in which BP0-3 exists in the
>> > > > status
>> > > > register but TB exists in another register.
>> > > > for example, mx25u12835f.
>> 
>> And like the mx25u3232f, but this bit is only OTP programmable! For
>> now,
>> I'd only add support for reading the TB bit to for this kind of
>> flashes,
>> to prevent accidentially program this bit. It would be up to the
>> board
>> manufacturer how to actually set the bit.
>> 
>> Like having a TB_READ_ONLY flag.
>> 
>> Its also some kind of asymmetrical because you can only set it one
>> way,
>> eg. you can OTP the flash to be TB=1. Then you can be sure that the
>> flash
>> will always be TB=1. But OTOH you cannot be sure that a TB=0 flash
>> will
>> always be a TB=0 flash, because you cannot lock that bit.
>> 
>> Any thoughts?
>> 
> 
> Actually, I didn't get the chance to take a look at some flash that has
> TB bit in configuration register. Currently mainline kernel just care
> flashes that has TB bit in SR and SPI_NOR_HAS_TB can be set only such
> flashes(as you could see in comment). It seems neccessary to add
> another functions and flag for mx25u3232f case.
> Is there any flash that has OTP programmable TB bit in SR?

Not that I'm aware of. My intention wasn't to have anything changed in
this patch series regarding these flashes, just to ask if anyone else
has ideas how they would solve the mx25u3232f (or mx25u12835f) case.

-michael

> Tudor and me were saying that there is some flash that has not TB bit
> in *SR* even if it has BP3 bit in SR. So it seems unnecessary to make
> correlated flag like SPI_NOR_SR_TB_BIT6_BP3_BIT5 for convenience.
> 
>> -michael
>> 
>> > > > I haven't tested yet, but according to the datasheet, I think
>> > > > this
>> > > > patch can support 4bit block protection for the flash.
>> > > >
>> > > > In order to embrace the case, how about letting them as It is.
>> > > > Is there any suggestion?
>> >
>> > Ok, this info should go in the commit message, together with
>> > details
>> > about
>> > which flashes were tested.
>> >
>> > I didn't know that the TB bit can be defined in the Configuration
>> > register.
>> > This means that your suggestion with dedicated macros for BP3 and
>> > TB is
>> > fine.
>> >
>> > I looked a bit over your patches, they are in a pretty good shape.
>> > I
>> > saw
>> > something that can be improved on patch 2/3, but I didn't manage
>> > to
>> > finish the
>> > review. Your patches are the first on my TODO list, but now I'm a
>> > bit
>> > busy. I
>> > hope that I'll come with a complete review by the end of the next
>> > week.
>> > I'm
>> > going to do tests on few flashes too, to make sure that BP0-2 was
>> > not
>> > affected.
>> >
>> > In the meantime, maybe Michael or John can review/test your
>> > patches,
>> > they
>> > showed interest in BP0-3 support.
>> >
>> > Cheers,
>> > ta
>> 
>> 
> Thanks,
> Jungseung Lee

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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[chenxiang (M)]

Hi Jungseung Lee,

在 2020/1/17 23:06, Jungseung Lee 写道:
> Hi, Tudor,
>
> On Tue, Jan 14, 2020 at 7:49 PM <Tudor.Ambarus@microchip.com> wrote:
>> Hi, Jungseung,
>>
>> Thanks for working on this.
>>
>> On Monday, January 13, 2020 7:59:06 AM EET Jungseung Lee wrote:
>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the
>>> content is safe
>>>
>>> Currently, we are supporting block protection only for
>>> flash chips with 3 block protection bits in the SR register.
>>> This patch enables block protection support for some flash with
>>> 4 block protection bits(bp0-3).
>> Some? Isn't this generic for all the flashes that support BP0-3?
>>
> This one would be a generic solution to support BP0-3 on Status Register.
> >From my study, this covers all the flashes listed on spi-nor.c that
> have BP0-3 bit on SR.
> It looks like I have to change this description.
>
> Note that it is NOT for some flashes that have BP0-3 in another register.
> As you know, just like SPI_NOR_HAS_TB did.
>
>>> Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
>>> ---
>>> v3 :
>>>    Fix wrong ofs calculation on v2 patch
>>> v2 :
>>>    Add sample table portion about 4bit block protection on the comment
>>>    Trivial coding style change
>>>
>>>   drivers/mtd/spi-nor/spi-nor.c | 127 +++++++++++++++++++++++++++++-----
>>>   include/linux/mtd/spi-nor.h   |   8 +++
>>>   2 files changed, 119 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
>>> index e3da6a8654a8..7e8af6c4fdfa 100644
>>> --- a/drivers/mtd/spi-nor/spi-nor.c
>>> +++ b/drivers/mtd/spi-nor/spi-nor.c
>>> @@ -238,6 +238,14 @@ struct flash_info {
>>>                                           * status register. Must be used
>>> with * SPI_NOR_HAS_TB.
>>>                                           */
>>> +#define SPI_NOR_HAS_BP3                BIT(17) /*
>>> +                                        * Flash SR has 4 bit fields (BP0-3)
>>> +                                        * for block protection.
>>> +                                        */
>>> +#define SPI_NOR_BP3_SR_BIT6    BIT(18) /*
>>> +                                        * BP3 is bit 6 of status register.
>>> +                                        * Must be used with
>> Are we safe to replace SPI_NOR_TB_SR_BIT6 and SPI_NOR_BP3_SR_BIT6 with a
>> SPI_NOR_SR_TB_BIT6_BP3_BIT5? Or maybe with a SPI_NOR_SR_BP3_BIT6_TB_BIT5, how
>> is more convenient?
>>
> Let's think about some flash in which BP0-3 exists in the status
> register but TB exists in another register.
> for example, mx25u12835f.
> I haven't tested yet, but according to the datasheet, I think this
> patch can support 4bit block protection for the flash.
>
> In order to embrace the case, how about letting them as It is.
> Is there any suggestion?

In my board(hisilicon D06) there is  a mx25u12835f Flash, and i enable 
SPI_NOR_HAS_LOCK and SPI_NOR_HAS_BP3 which is not enabled in spi-nor.c, 
find it seems not work:

Euler:~ # ls /dev/mtd0
/dev/mtd0
Euler:~ # ./flash_lock -i /dev/mtd0
Device: /dev/mtd0
Start: 0
Len: 0x1000000
Lock status: unlocked
Return code: 0
Euler:~ #
Euler:~ # ./flash_lock /dev/mtd0
flash_lock: error!: could not lock device: /dev/mtd0

             error 5 (Input/output error)
Euler:~ # ./flash_lock -i /dev/mtd0
Device: /dev/mtd0
Start: 0
Len: 0x1000000
Lock status: locked
Return code: 1
Euler:~ #

I find that in function spi_nor_write_sr_and_check(), if spi_nor has 
16bit SR, spi_nor_write_16bit_sr_and_check() will be called, if not 
spi_nor_write_sr1_and_check() will be called.
For mx25u12835f, it just has 8bit SR, but SNOR_F_HAS_16BIT_SR is set as 
default, so it causes above issue;
Even hack the code to not set flag SNOR_F_HAS_16BIT_SR, it seems that 
lock is still not valided as Program/Erase still success even if it is 
locked:

Euler:~ # ./flash_lock -i /dev/mtd0
Device: /dev/mtd0
Start: 0
Len: 0x1000000
Lock status: unlocked
Return code: 0
Euler:~ #
Euler:~ # ./mtd_debug erase /dev/mtd0 0xe40000 4096
Erased 4096 bytes from address 0x00e40000 in flash
Euler:~ #
Euler:~ # ./flash_lock /dev/mtd0
Euler:~ #
Euler:~ # ./flash_lock -i /dev/mtd0
Device: /dev/mtd0
Start: 0
Len: 0x1000000
Lock status: locked
Return code: 1
Euler:~ #
Euler:~ # ./mtd_debug erase /dev/mtd0 0xe40000 4096
Erased 4096 bytes from address 0x00e40000 in flash
Euler:~ # ./flash_lock -i /dev/mtd0
Device: /dev/mtd0
Start: 0
Len: 0x1000000
Lock status: locked
Return code: 1
Euler:~ #
Euler:~ #


Thanks,
chenxiang


>
>> Cheers,
>> ta
>>
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/
>
> .
>



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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Hi,

2020-02-11 (화), 15:52 +0800, chenxiang (M):
> Hi Jungseung Lee,
> 
> 在 2020/1/17 23:06, Jungseung Lee 写道:
> > Hi, Tudor,
> > 
> > On Tue, Jan 14, 2020 at 7:49 PM <Tudor.Ambarus@microchip.com>
> > wrote:
> > > Hi, Jungseung,
> > > 
> > > Thanks for working on this.
> > > 
> > > On Monday, January 13, 2020 7:59:06 AM EET Jungseung Lee wrote:
> > > > EXTERNAL EMAIL: Do not click links or open attachments unless
> > > > you know the
> > > > content is safe
> > > > 
> > > > Currently, we are supporting block protection only for
> > > > flash chips with 3 block protection bits in the SR register.
> > > > This patch enables block protection support for some flash with
> > > > 4 block protection bits(bp0-3).
> > > 
> > > Some? Isn't this generic for all the flashes that support BP0-3?
> > > 
> > 
> > This one would be a generic solution to support BP0-3 on Status
> > Register.
> > > From my study, this covers all the flashes listed on spi-nor.c
> > > that
> > 
> > have BP0-3 bit on SR.
> > It looks like I have to change this description.
> > 
> > Note that it is NOT for some flashes that have BP0-3 in another
> > register.
> > As you know, just like SPI_NOR_HAS_TB did.
> > 
> > > > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> > > > ---
> > > > v3 :
> > > >    Fix wrong ofs calculation on v2 patch
> > > > v2 :
> > > >    Add sample table portion about 4bit block protection on the
> > > > comment
> > > >    Trivial coding style change
> > > > 
> > > >   drivers/mtd/spi-nor/spi-nor.c | 127
> > > > +++++++++++++++++++++++++++++-----
> > > >   include/linux/mtd/spi-nor.h   |   8 +++
> > > >   2 files changed, 119 insertions(+), 16 deletions(-)
> > > > 
> > > > diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-
> > > > nor/spi-nor.c
> > > > index e3da6a8654a8..7e8af6c4fdfa 100644
> > > > --- a/drivers/mtd/spi-nor/spi-nor.c
> > > > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > > > @@ -238,6 +238,14 @@ struct flash_info {
> > > >                                           * status register.
> > > > Must be used
> > > > with * SPI_NOR_HAS_TB.
> > > >                                           */
> > > > +#define SPI_NOR_HAS_BP3                BIT(17) /*
> > > > +                                        * Flash SR has 4 bit
> > > > fields (BP0-3)
> > > > +                                        * for block
> > > > protection.
> > > > +                                        */
> > > > +#define SPI_NOR_BP3_SR_BIT6    BIT(18) /*
> > > > +                                        * BP3 is bit 6 of
> > > > status register.
> > > > +                                        * Must be used with
> > > 
> > > Are we safe to replace SPI_NOR_TB_SR_BIT6 and SPI_NOR_BP3_SR_BIT6
> > > with a
> > > SPI_NOR_SR_TB_BIT6_BP3_BIT5? Or maybe with a
> > > SPI_NOR_SR_BP3_BIT6_TB_BIT5, how
> > > is more convenient?
> > > 
> > 
> > Let's think about some flash in which BP0-3 exists in the status
> > register but TB exists in another register.
> > for example, mx25u12835f.
> > I haven't tested yet, but according to the datasheet, I think this
> > patch can support 4bit block protection for the flash.
> > 
> > In order to embrace the case, how about letting them as It is.
> > Is there any suggestion?
> 
> In my board(hisilicon D06) there is  a mx25u12835f Flash, and i
> enable 
> SPI_NOR_HAS_LOCK and SPI_NOR_HAS_BP3 which is not enabled in spi-
> nor.c, 
> find it seems not work:
> 
> Euler:~ # ls /dev/mtd0
> /dev/mtd0
> Euler:~ # ./flash_lock -i /dev/mtd0
> Device: /dev/mtd0
> Start: 0
> Len: 0x1000000
> Lock status: unlocked
> Return code: 0
> Euler:~ #
> Euler:~ # ./flash_lock /dev/mtd0
> flash_lock: error!: could not lock device: /dev/mtd0
> 
>              error 5 (Input/output error)
> Euler:~ # ./flash_lock -i /dev/mtd0
> Device: /dev/mtd0
> Start: 0
> Len: 0x1000000
> Lock status: locked
> Return code: 1
> Euler:~ #
> 
> I find that in function spi_nor_write_sr_and_check(), if spi_nor has 
> 16bit SR, spi_nor_write_16bit_sr_and_check() will be called, if not 
> spi_nor_write_sr1_and_check() will be called.
> For mx25u12835f, it just has 8bit SR, but SNOR_F_HAS_16BIT_SR is set
> as 
> default, so it causes above issue;
> Even hack the code to not set flag SNOR_F_HAS_16BIT_SR, it seems
> that 
> lock is still not valided as Program/Erase still success even if it
> is 
> locked:
> 

Could you dump sr register value?
But if you are using old kernel or the flash doesn't have FSR error
bits, erase/program operation failure couldn't be detected.

refer this one.

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.6-rc4&id=20ccb993f29bd6ad17699dd0b349db086e3ca719

I am planning to post new patch for 4bit Block protection soon. I would
appreciate it if you check there too.

Thanks,

> Euler:~ # ./flash_lock -i /dev/mtd0
> Device: /dev/mtd0
> Start: 0
> Len: 0x1000000
> Lock status: unlocked
> Return code: 0
> Euler:~ #
> Euler:~ # ./mtd_debug erase /dev/mtd0 0xe40000 4096
> Erased 4096 bytes from address 0x00e40000 in flash
> Euler:~ #
> Euler:~ # ./flash_lock /dev/mtd0
> Euler:~ #
> Euler:~ # ./flash_lock -i /dev/mtd0
> Device: /dev/mtd0
> Start: 0
> Len: 0x1000000
> Lock status: locked
> Return code: 1
> Euler:~ #
> Euler:~ # ./mtd_debug erase /dev/mtd0 0xe40000 4096
> Erased 4096 bytes from address 0x00e40000 in flash
> Euler:~ # ./flash_lock -i /dev/mtd0
> Device: /dev/mtd0
> Start: 0
> Len: 0x1000000
> Lock status: locked
> Return code: 1
> Euler:~ #
> Euler:~ #
> 
> 
> Thanks,
> chenxiang
> 
> 
> > 
> > > Cheers,
> > > ta
> > > 
> > 
> > ______________________________________________________
> > Linux MTD discussion mailing list
> > 
https://protect2.fireeye.com/url?k=81f52bac-dc2196e8-81f4a0e3-0cc47a31381a-cfeff2fb749261ae&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
> > 
> > .
> > 
> 
> 
> 


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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[chenxiang (M)]

Hi,

在 2020/3/4 13:20, Jungseung Lee 写道:
> Hi,
>
> 2020-02-11 (화), 15:52 +0800, chenxiang (M):
>> Hi Jungseung Lee,
>>
>> 在 2020/1/17 23:06, Jungseung Lee 写道:
>>> Hi, Tudor,
>>>
>>> On Tue, Jan 14, 2020 at 7:49 PM <Tudor.Ambarus@microchip.com>
>>> wrote:
>>>> Hi, Jungseung,
>>>>
>>>> Thanks for working on this.
>>>>
>>>> On Monday, January 13, 2020 7:59:06 AM EET Jungseung Lee wrote:
>>>>> EXTERNAL EMAIL: Do not click links or open attachments unless
>>>>> you know the
>>>>> content is safe
>>>>>
>>>>> Currently, we are supporting block protection only for
>>>>> flash chips with 3 block protection bits in the SR register.
>>>>> This patch enables block protection support for some flash with
>>>>> 4 block protection bits(bp0-3).
>>>> Some? Isn't this generic for all the flashes that support BP0-3?
>>>>
>>> This one would be a generic solution to support BP0-3 on Status
>>> Register.
>>>>  From my study, this covers all the flashes listed on spi-nor.c
>>>> that
>>> have BP0-3 bit on SR.
>>> It looks like I have to change this description.
>>>
>>> Note that it is NOT for some flashes that have BP0-3 in another
>>> register.
>>> As you know, just like SPI_NOR_HAS_TB did.
>>>
>>>>> Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
>>>>> ---
>>>>> v3 :
>>>>>     Fix wrong ofs calculation on v2 patch
>>>>> v2 :
>>>>>     Add sample table portion about 4bit block protection on the
>>>>> comment
>>>>>     Trivial coding style change
>>>>>
>>>>>    drivers/mtd/spi-nor/spi-nor.c | 127
>>>>> +++++++++++++++++++++++++++++-----
>>>>>    include/linux/mtd/spi-nor.h   |   8 +++
>>>>>    2 files changed, 119 insertions(+), 16 deletions(-)
>>>>>
>>>>> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-
>>>>> nor/spi-nor.c
>>>>> index e3da6a8654a8..7e8af6c4fdfa 100644
>>>>> --- a/drivers/mtd/spi-nor/spi-nor.c
>>>>> +++ b/drivers/mtd/spi-nor/spi-nor.c
>>>>> @@ -238,6 +238,14 @@ struct flash_info {
>>>>>                                            * status register.
>>>>> Must be used
>>>>> with * SPI_NOR_HAS_TB.
>>>>>                                            */
>>>>> +#define SPI_NOR_HAS_BP3                BIT(17) /*
>>>>> +                                        * Flash SR has 4 bit
>>>>> fields (BP0-3)
>>>>> +                                        * for block
>>>>> protection.
>>>>> +                                        */
>>>>> +#define SPI_NOR_BP3_SR_BIT6    BIT(18) /*
>>>>> +                                        * BP3 is bit 6 of
>>>>> status register.
>>>>> +                                        * Must be used with
>>>> Are we safe to replace SPI_NOR_TB_SR_BIT6 and SPI_NOR_BP3_SR_BIT6
>>>> with a
>>>> SPI_NOR_SR_TB_BIT6_BP3_BIT5? Or maybe with a
>>>> SPI_NOR_SR_BP3_BIT6_TB_BIT5, how
>>>> is more convenient?
>>>>
>>> Let's think about some flash in which BP0-3 exists in the status
>>> register but TB exists in another register.
>>> for example, mx25u12835f.
>>> I haven't tested yet, but according to the datasheet, I think this
>>> patch can support 4bit block protection for the flash.
>>>
>>> In order to embrace the case, how about letting them as It is.
>>> Is there any suggestion?
>> In my board(hisilicon D06) there is  a mx25u12835f Flash, and i
>> enable
>> SPI_NOR_HAS_LOCK and SPI_NOR_HAS_BP3 which is not enabled in spi-
>> nor.c,
>> find it seems not work:
>>
>> Euler:~ # ls /dev/mtd0
>> /dev/mtd0
>> Euler:~ # ./flash_lock -i /dev/mtd0
>> Device: /dev/mtd0
>> Start: 0
>> Len: 0x1000000
>> Lock status: unlocked
>> Return code: 0
>> Euler:~ #
>> Euler:~ # ./flash_lock /dev/mtd0
>> flash_lock: error!: could not lock device: /dev/mtd0
>>
>>               error 5 (Input/output error)
>> Euler:~ # ./flash_lock -i /dev/mtd0
>> Device: /dev/mtd0
>> Start: 0
>> Len: 0x1000000
>> Lock status: locked
>> Return code: 1
>> Euler:~ #
>>
>> I find that in function spi_nor_write_sr_and_check(), if spi_nor has
>> 16bit SR, spi_nor_write_16bit_sr_and_check() will be called, if not
>> spi_nor_write_sr1_and_check() will be called.
>> For mx25u12835f, it just has 8bit SR, but SNOR_F_HAS_16BIT_SR is set
>> as
>> default, so it causes above issue;
>> Even hack the code to not set flag SNOR_F_HAS_16BIT_SR, it seems
>> that
>> lock is still not valided as Program/Erase still success even if it
>> is
>> locked:
>>
> Could you dump sr register value?
> But if you are using old kernel or the flash doesn't have FSR error
> bits, erase/program operation failure couldn't be detected.
>
> refer this one.
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.6-rc4&id=20ccb993f29bd6ad17699dd0b349db086e3ca719

The kernel i used is 5.5-rc4, and it includes the above patch.
I also checked the datasheet of mx25u12835f flash, and it doesn't have 
FSR register, but it has other register SCUR(Security Reigster, 
bit6&bit5 are
E_FAIL/P_FAIL which i think the function of them are like the bit5&bit4 
of FSR register) .


>
> I am planning to post new patch for 4bit Block protection soon. I would
> appreciate it if you check there too.

It's my pleasure to check it.

>
> Thanks,
>
>> Euler:~ # ./flash_lock -i /dev/mtd0
>> Device: /dev/mtd0
>> Start: 0
>> Len: 0x1000000
>> Lock status: unlocked
>> Return code: 0
>> Euler:~ #
>> Euler:~ # ./mtd_debug erase /dev/mtd0 0xe40000 4096
>> Erased 4096 bytes from address 0x00e40000 in flash
>> Euler:~ #
>> Euler:~ # ./flash_lock /dev/mtd0
>> Euler:~ #
>> Euler:~ # ./flash_lock -i /dev/mtd0
>> Device: /dev/mtd0
>> Start: 0
>> Len: 0x1000000
>> Lock status: locked
>> Return code: 1
>> Euler:~ #
>> Euler:~ # ./mtd_debug erase /dev/mtd0 0xe40000 4096
>> Erased 4096 bytes from address 0x00e40000 in flash
>> Euler:~ # ./flash_lock -i /dev/mtd0
>> Device: /dev/mtd0
>> Start: 0
>> Len: 0x1000000
>> Lock status: locked
>> Return code: 1
>> Euler:~ #
>> Euler:~ #
>>
>>
>> Thanks,
>> chenxiang
>>
>>
>>>> Cheers,
>>>> ta
>>>>
>>> ______________________________________________________
>>> Linux MTD discussion mailing list
>>>
> https://protect2.fireeye.com/url?k=81f52bac-dc2196e8-81f4a0e3-0cc47a31381a-cfeff2fb749261ae&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
>>> .
>>>
>>
>>
>
> .
>



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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Hi,

2020-03-04 (수), 16:36 +0800, chenxiang (M):
> Hi,
> 
> 在 2020/3/4 13:20, Jungseung Lee 写道:
> > Hi,
> > 
> > 2020-02-11 (화), 15:52 +0800, chenxiang (M):
> > > Hi Jungseung Lee,
> > > 
> > > 在 2020/1/17 23:06, Jungseung Lee 写道:
> > > > Hi, Tudor,
> > > > 
> > > > On Tue, Jan 14, 2020 at 7:49 PM <Tudor.Ambarus@microchip.com>
> > > > wrote:
> > > > > Hi, Jungseung,
> > > > > 
> > > > > Thanks for working on this.
> > > > > 
> > > > > On Monday, January 13, 2020 7:59:06 AM EET Jungseung Lee
> > > > > wrote:
> > > > > > EXTERNAL EMAIL: Do not click links or open attachments
> > > > > > unless
> > > > > > you know the
> > > > > > content is safe
> > > > > > 
> > > > > > Currently, we are supporting block protection only for
> > > > > > flash chips with 3 block protection bits in the SR
> > > > > > register.
> > > > > > This patch enables block protection support for some flash
> > > > > > with
> > > > > > 4 block protection bits(bp0-3).
> > > > > 
> > > > > Some? Isn't this generic for all the flashes that support
> > > > > BP0-3?
> > > > > 
> > > > 
> > > > This one would be a generic solution to support BP0-3 on Status
> > > > Register.
> > > > >  From my study, this covers all the flashes listed on spi-
> > > > > nor.c
> > > > > that
> > > > 
> > > > have BP0-3 bit on SR.
> > > > It looks like I have to change this description.
> > > > 
> > > > Note that it is NOT for some flashes that have BP0-3 in another
> > > > register.
> > > > As you know, just like SPI_NOR_HAS_TB did.
> > > > 
> > > > > > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> > > > > > ---
> > > > > > v3 :
> > > > > >     Fix wrong ofs calculation on v2 patch
> > > > > > v2 :
> > > > > >     Add sample table portion about 4bit block protection on
> > > > > > the
> > > > > > comment
> > > > > >     Trivial coding style change
> > > > > > 
> > > > > >    drivers/mtd/spi-nor/spi-nor.c | 127
> > > > > > +++++++++++++++++++++++++++++-----
> > > > > >    include/linux/mtd/spi-nor.h   |   8 +++
> > > > > >    2 files changed, 119 insertions(+), 16 deletions(-)
> > > > > > 
> > > > > > diff --git a/drivers/mtd/spi-nor/spi-nor.c
> > > > > > b/drivers/mtd/spi-
> > > > > > nor/spi-nor.c
> > > > > > index e3da6a8654a8..7e8af6c4fdfa 100644
> > > > > > --- a/drivers/mtd/spi-nor/spi-nor.c
> > > > > > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > > > > > @@ -238,6 +238,14 @@ struct flash_info {
> > > > > >                                            * status
> > > > > > register.
> > > > > > Must be used
> > > > > > with * SPI_NOR_HAS_TB.
> > > > > >                                            */
> > > > > > +#define SPI_NOR_HAS_BP3                BIT(17) /*
> > > > > > +                                        * Flash SR has 4
> > > > > > bit
> > > > > > fields (BP0-3)
> > > > > > +                                        * for block
> > > > > > protection.
> > > > > > +                                        */
> > > > > > +#define SPI_NOR_BP3_SR_BIT6    BIT(18) /*
> > > > > > +                                        * BP3 is bit 6 of
> > > > > > status register.
> > > > > > +                                        * Must be used
> > > > > > with
> > > > > 
> > > > > Are we safe to replace SPI_NOR_TB_SR_BIT6 and
> > > > > SPI_NOR_BP3_SR_BIT6
> > > > > with a
> > > > > SPI_NOR_SR_TB_BIT6_BP3_BIT5? Or maybe with a
> > > > > SPI_NOR_SR_BP3_BIT6_TB_BIT5, how
> > > > > is more convenient?
> > > > > 
> > > > 
> > > > Let's think about some flash in which BP0-3 exists in the
> > > > status
> > > > register but TB exists in another register.
> > > > for example, mx25u12835f.
> > > > I haven't tested yet, but according to the datasheet, I think
> > > > this
> > > > patch can support 4bit block protection for the flash.
> > > > 
> > > > In order to embrace the case, how about letting them as It is.
> > > > Is there any suggestion?
> > > 
> > > In my board(hisilicon D06) there is  a mx25u12835f Flash, and i
> > > enable
> > > SPI_NOR_HAS_LOCK and SPI_NOR_HAS_BP3 which is not enabled in spi-
> > > nor.c,
> > > find it seems not work:
> > > 
> > > Euler:~ # ls /dev/mtd0
> > > /dev/mtd0
> > > Euler:~ # ./flash_lock -i /dev/mtd0
> > > Device: /dev/mtd0
> > > Start: 0
> > > Len: 0x1000000
> > > Lock status: unlocked
> > > Return code: 0
> > > Euler:~ #
> > > Euler:~ # ./flash_lock /dev/mtd0
> > > flash_lock: error!: could not lock device: /dev/mtd0
> > > 
> > >               error 5 (Input/output error)
> > > Euler:~ # ./flash_lock -i /dev/mtd0
> > > Device: /dev/mtd0
> > > Start: 0
> > > Len: 0x1000000
> > > Lock status: locked
> > > Return code: 1
> > > Euler:~ #
> > > 
> > > I find that in function spi_nor_write_sr_and_check(), if spi_nor
> > > has
> > > 16bit SR, spi_nor_write_16bit_sr_and_check() will be called, if
> > > not
> > > spi_nor_write_sr1_and_check() will be called.
> > > For mx25u12835f, it just has 8bit SR, but SNOR_F_HAS_16BIT_SR is
> > > set
> > > as
> > > default, so it causes above issue;
> > > Even hack the code to not set flag SNOR_F_HAS_16BIT_SR, it seems
> > > that
> > > lock is still not valided as Program/Erase still success even if
> > > it
> > > is
> > > locked:
> > > 
> > 
> > Could you dump sr register value?
> > But if you are using old kernel or the flash doesn't have FSR error
> > bits, erase/program operation failure couldn't be detected.
> > 
> > refer this one.
> > 
> > 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.6-rc4&id=20ccb993f29bd6ad17699dd0b349db086e3ca719
> 
> The kernel i used is 5.5-rc4, and it includes the above patch.
> I also checked the datasheet of mx25u12835f flash, and it doesn't
> have 
> FSR register, but it has other register SCUR(Security Reigster, 
> bit6&bit5 are
> E_FAIL/P_FAIL which i think the function of them are like the
> bit5&bit4 
> of FSR register) .
> 

So that is the one not having FSR register. If SCUR is used elsewhere
enough, we could add a feature for it later.

Thanks,
> 
> > 
> > I am planning to post new patch for 4bit Block protection soon. I
> > would
> > appreciate it if you check there too.
> 
> It's my pleasure to check it.
> 
> > 
> > Thanks,
> > 
> > > Euler:~ # ./flash_lock -i /dev/mtd0
> > > Device: /dev/mtd0
> > > Start: 0
> > > Len: 0x1000000
> > > Lock status: unlocked
> > > Return code: 0
> > > Euler:~ #
> > > Euler:~ # ./mtd_debug erase /dev/mtd0 0xe40000 4096
> > > Erased 4096 bytes from address 0x00e40000 in flash
> > > Euler:~ #
> > > Euler:~ # ./flash_lock /dev/mtd0
> > > Euler:~ #
> > > Euler:~ # ./flash_lock -i /dev/mtd0
> > > Device: /dev/mtd0
> > > Start: 0
> > > Len: 0x1000000
> > > Lock status: locked
> > > Return code: 1
> > > Euler:~ #
> > > Euler:~ # ./mtd_debug erase /dev/mtd0 0xe40000 4096
> > > Erased 4096 bytes from address 0x00e40000 in flash
> > > Euler:~ # ./flash_lock -i /dev/mtd0
> > > Device: /dev/mtd0
> > > Start: 0
> > > Len: 0x1000000
> > > Lock status: locked
> > > Return code: 1
> > > Euler:~ #
> > > Euler:~ #
> > > 
> > > 
> > > Thanks,
> > > chenxiang
> > > 
> > > 
> > > > > Cheers,
> > > > > ta
> > > > > 
> > > > 
> > > > ______________________________________________________
> > > > Linux MTD discussion mailing list
> > > > 
> > 
> > 
https://protect2.fireeye.com/url?k=81f52bac-dc2196e8-81f4a0e3-0cc47a31381a-cfeff2fb749261ae&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
> > > > .
> > > > 
> > > 
> > > 
> > 
> > .
> > 
> 
> 
> 


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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Hi,

> Currently, we are supporting block protection only for
> flash chips with 3 block protection bits in the SR register.
> This patch enables block protection support for some flash with
> 4 block protection bits(bp0-3).
> 
> Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> ---
> v3 :
>   Fix wrong ofs calculation on v2 patch
> v2 :
>   Add sample table portion about 4bit block protection on the comment
>   Trivial coding style change
> 
>  drivers/mtd/spi-nor/spi-nor.c | 127 +++++++++++++++++++++++++++++-----
>  include/linux/mtd/spi-nor.h   |   8 +++
>  2 files changed, 119 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index e3da6a8654a8..7e8af6c4fdfa 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -238,6 +238,14 @@ struct flash_info {
>  					 * status register. Must be used with
>  					 * SPI_NOR_HAS_TB.
>  					 */
> +#define SPI_NOR_HAS_BP3		BIT(17)	/*
> +					 * Flash SR has 4 bit fields (BP0-3)
> +					 * for block protection.
> +					 */
> +#define SPI_NOR_BP3_SR_BIT6	BIT(18)	/*
> +					 * BP3 is bit 6 of status register.
> +					 * Must be used with SPI_NOR_HAS_BP3.
> +					 */
>  
>  	/* Part specific fixup hooks. */
>  	const struct spi_nor_fixups *fixups;
> @@ -1767,23 +1775,47 @@ static void stm_get_locked_range(struct spi_nor *nor, u8 sr, loff_t *ofs,
>  	struct mtd_info *mtd = &nor->mtd;
>  	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
>  	u8 tb_mask = SR_TB_BIT5;
> -	int pow;
> +	u8 bp;
> +	int pow = 0;
>  
>  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>  		tb_mask = SR_TB_BIT6;
>  
> -	if (!(sr & mask)) {
> -		/* No protection */
> -		*ofs = 0;
> -		*len = 0;
> +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> +		u8 tmp;
> +
> +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
> +			tmp = sr & (mask | SR_BP3_BIT6);
> +		else
> +			tmp = sr & (mask | SR_BP3_BIT5);
> +
> +		if (tmp & SR_BP3_BIT6)
> +			tmp = (tmp & ~BIT(6)) | BIT(5);
> +
> +		bp = tmp >> SR_BP_SHIFT;
> +		if (!bp) {
> +			*ofs = 0;
> +			*len = 0;
> +			return;
> +		}
> +		if (bp <= ilog2(nor->n_sectors))
> +			pow = ilog2(nor->n_sectors) + 1 - bp;
>  	} else {
> -		pow = ((sr & mask) ^ mask) >> SR_BP_SHIFT;
> -		*len = mtd->size >> pow;
> -		if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
> +		bp = (sr & mask) >> SR_BP_SHIFT;
> +		if (!bp) {
>  			*ofs = 0;
> -		else
> -			*ofs = mtd->size - *len;
> +			*len = 0;
> +			return;
> +		}
> +		pow = bp ^ (mask >> SR_BP_SHIFT);
>  	}
> +
> +	*len = mtd->size >> pow;
> +
> +	if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
> +		*ofs = 0;
> +	else
> +		*ofs = mtd->size - *len;
>  }
>  
>  /*
> @@ -1823,7 +1855,7 @@ static int stm_is_unlocked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
>  
>  /*
>   * Lock a region of the flash. Compatible with ST Micro and similar flash.
> - * Supports the block protection bits BP{0,1,2} in the status register
> + * Supports the block protection bits BP{0,1,2,3} in the status register
>   * (SR). Does not support these features found in newer SR bitfields:
>   *   - SEC: sector/block protect - only handle SEC=0 (block protect)
>   *   - CMP: complement protect - only support CMP=0 (range is not complemented)
> @@ -1831,7 +1863,7 @@ static int stm_is_unlocked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
>   * Support for the following is provided conditionally for some flash:
>   *   - TB: top/bottom protect
>   *
> - * Sample table portion for 8MB flash (Winbond w25q64fw):
> + * Sample table portion for 8MB flash (Winbond w25q64fw / BP0-2):
>   *
>   *   SEC  |  TB   |  BP2  |  BP1  |  BP0  |  Prot Length  | Protected Portion
>   *  --------------------------------------------------------------------------
> @@ -1851,6 +1883,32 @@ static int stm_is_unlocked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
>   *    0   |   1   |   1   |   0   |   1   |  2 MB         | Lower 1/4
>   *    0   |   1   |   1   |   1   |   0   |  4 MB         | Lower 1/2
>   *
> + * Sample table portion for 64MB flash (Micron n25q512ax3 / BP0-3):
> + *
> + *   TB   |  BP3  |  BP2  |  BP1  |  BP0  |  Prot Length  | Protected Portion
> + *  --------------------------------------------------------------------------
> + *    0   |   0   |   0   |   0   |   0   |  NONE         | NONE
> + *    0   |   0   |   0   |   0   |   1   |   64 KB       | Upper 1/1024
> + *    0   |   0   |   0   |   1   |   0   |  128 KB       | Upper 1/512
> + *    0   |   0   |   0   |   1   |   1   |  256 KB       | Upper 1/256
> + *   ...
> + *    0   |   1   |   0   |   0   |   1   |  16 MB        | Upper 1/4
> + *    0   |   1   |   0   |   1   |   0   |  32 MB        | Upper 1/2
> + *    0   |   1   |   0   |   1   |   1   |  64 MB        | ALL
> + *    0   |   1   |   1   |   0   |   0   |  64 MB        | ALL
> + *   ...
> + *  ------|-------|-------|-------|-------|---------------|-------------------
> + *    1   |   0   |   0   |   0   |   0   |   NONE        | NONE
> + *    1   |   0   |   0   |   0   |   1   |   64 KB       | Lower 1/1024
> + *    1   |   0   |   0   |   1   |   0   |  128 KB       | Lower 1/512
> + *    1   |   0   |   0   |   1   |   1   |  256 KB       | Lower 1/256
> + *   ...
> + *    1   |   1   |   0   |   0   |   1   |  16 MB        | Lower 1/4
> + *    1   |   1   |   0   |   1   |   0   |  32 MB        | Lower 1/2
> + *    1   |   1   |   0   |   1   |   1   |  64 MB        | ALL
> + *    1   |   1   |   1   |   0   |   0   |  64 MB        | ALL
> + *   ...
> + *
>   * Returns negative on errors, 0 on success.
>   */
>  static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
> @@ -1898,6 +1956,12 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
>  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>  		tb_mask = SR_TB_BIT6;
>  
> +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
> +			mask = mask | SR_BP3_BIT6;
> +		else
> +			mask = mask | SR_BP3_BIT5;
> +	}
>  	/*
>  	 * Need smallest pow such that:
>  	 *
> @@ -1908,7 +1972,17 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
>  	 *   pow = ceil(log2(size / len)) = log2(size) - floor(log2(len))
>  	 */
>  	pow = ilog2(mtd->size) - ilog2(lock_len);
> -	val = mask - (pow << SR_BP_SHIFT);
> +
> +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> +		val = ilog2(nor->n_sectors) + 1 - pow;

Why do you use a new calculation here? As far as I can see, the method is
the same except that is has one bit more. That also raises the question why
n_sectors is now needed?

Can't we just initialize the mask with

mask = SR_BP2 | SR_BP1 | SR_BP0;
if (nor->flags & SNOR_F_HAS_SR_BP3)
    mask |= SR_BP3_BIT5;

do the calculation and checks and then move the SR_BP3_BIT5 to SR_BP3_BIT6
if SNOR_F_HAS_SR_BP3_BIT6 is set.

> +		val = val << SR_BP_SHIFT;
> +
> +		if (val & BIT(5) && mask & SR_BP3_BIT6)
> +			val = (val & ~BIT(5)) | BIT(6);
> +	} else {
> +		val = mask - (pow << SR_BP_SHIFT);
> +	}
> +
>  	if (val & ~mask)
>  		return -EINVAL;
>  	/* Don't "lock" with no region! */
> @@ -1983,6 +2057,13 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
>  
>  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>  		tb_mask = SR_TB_BIT6;
> +
> +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
> +			mask = mask | SR_BP3_BIT6;
> +		else
> +			mask = mask | SR_BP3_BIT5;
> +	}
>  	/*
>  	 * Need largest pow such that:
>  	 *
> @@ -1995,13 +2076,20 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
>  	pow = ilog2(mtd->size) - order_base_2(lock_len);
>  	if (lock_len == 0) {
>  		val = 0; /* fully unlocked */
> +	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
> +		val = ilog2(nor->n_sectors) + 1 - pow;
> +		val = val << SR_BP_SHIFT;
> +
> +		if (val & BIT(5) && mask & SR_BP3_BIT6)
> +			val = (val & ~BIT(5)) | BIT(6);
>  	} else {
>  		val = mask - (pow << SR_BP_SHIFT);
> -		/* Some power-of-two sizes are not supported */
> -		if (val & ~mask)
> -			return -EINVAL;
>  	}
>  
> +	/* Some power-of-two sizes are not supported */
> +	if (val & ~mask)
> +		return -EINVAL;
> +
>  	status_new = (status_old & ~mask & ~tb_mask) | val;
>  
>  	/* Don't protect status register if we're fully unlocked */
> @@ -4736,6 +4824,7 @@ static void spi_nor_info_init_params(struct spi_nor *nor)
>  	/* Set SPI NOR sizes. */
>  	params->size = (u64)info->sector_size * info->n_sectors;
>  	params->page_size = info->page_size;
> +	params->n_sectors = info->n_sectors;
>  
>  	if (!(info->flags & SPI_NOR_NO_FR)) {
>  		/* Default to Fast Read for DT and non-DT platform devices. */
> @@ -5192,6 +5281,11 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
>  		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
>  	if (info->flags & USE_CLSR)
>  		nor->flags |= SNOR_F_USE_CLSR;
> +	if (info->flags & SPI_NOR_HAS_BP3) {
> +		nor->flags |= SNOR_F_HAS_SR_BP3;
> +		if (info->flags & SPI_NOR_BP3_SR_BIT6)
> +			nor->flags |= SNOR_F_HAS_SR_BP3_BIT6;
> +	}
>  
>  	if (info->flags & SPI_NOR_NO_ERASE)
>  		mtd->flags |= MTD_NO_ERASE;
> @@ -5199,6 +5293,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
>  	mtd->dev.parent = dev;
>  	nor->page_size = params->page_size;
>  	mtd->writebufsize = nor->page_size;
> +	nor->n_sectors = params->n_sectors;
>  
>  	if (of_property_read_bool(np, "broken-flash-reset"))
>  		nor->flags |= SNOR_F_BROKEN_RESET;
> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> index 541c06d042e8..92d550501daf 100644
> --- a/include/linux/mtd/spi-nor.h
> +++ b/include/linux/mtd/spi-nor.h
> @@ -129,7 +129,9 @@
>  #define SR_BP1			BIT(3)	/* Block protect 1 */
>  #define SR_BP2			BIT(4)	/* Block protect 2 */
>  #define SR_TB_BIT5		BIT(5)	/* Top/Bottom protect */
> +#define SR_BP3_BIT5		BIT(5)	/* Block protect 3 */

maybe just name it SR_BP3? would also be more consistent with the proposal
above.

>  #define SR_TB_BIT6		BIT(6)	/* Top/Bottom protect */
> +#define SR_BP3_BIT6		BIT(6)	/* Block protect 3 */
>  #define SR_SRWD			BIT(7)	/* SR write protect */
>  /* Spansion/Cypress specific status bits */
>  #define SR_E_ERR		BIT(5)
> @@ -248,6 +250,8 @@ enum spi_nor_option_flags {
>  	SNOR_F_HAS_16BIT_SR	= BIT(9),
>  	SNOR_F_NO_READ_CR	= BIT(10),
>  	SNOR_F_HAS_SR_TB_BIT6	= BIT(11),
> +	SNOR_F_HAS_SR_BP3	= BIT(12),
> +	SNOR_F_HAS_SR_BP3_BIT6	= BIT(13),
>  
>  };
>  
> @@ -519,6 +523,7 @@ struct spi_nor_locking_ops {
>   *
>   * @size:		the flash memory density in bytes.
>   * @page_size:		the page size of the SPI NOR flash memory.
> + * @n_sectors:		number of sectors
>   * @hwcaps:		describes the read and page program hardware
>   *			capabilities.
>   * @reads:		read capabilities ordered by priority: the higher index
> @@ -541,6 +546,7 @@ struct spi_nor_locking_ops {
>  struct spi_nor_flash_parameter {
>  	u64				size;
>  	u32				page_size;
> +	u16				n_sectors;
>  
>  	struct spi_nor_hwcaps		hwcaps;
>  	struct spi_nor_read_command	reads[SNOR_CMD_READ_MAX];
> @@ -573,6 +579,7 @@ struct flash_info;
>   * @bouncebuf_size:	size of the bounce buffer
>   * @info:		spi-nor part JDEC MFR id and other info
>   * @page_size:		the page size of the SPI NOR
> + * @n_sector:		number of sectors
>   * @addr_width:		number of address bytes
>   * @erase_opcode:	the opcode for erasing a sector
>   * @read_opcode:	the read opcode
> @@ -599,6 +606,7 @@ struct spi_nor {
>  	size_t			bouncebuf_size;
>  	const struct flash_info	*info;
>  	u32			page_size;
> +	u16			n_sectors;
>  	u8			addr_width;
>  	u8			erase_opcode;
>  	u8			read_opcode;
> -- 
> 2.17.1
> 
> 
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/
> 

______________________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Hi, Michael

2020-01-22 (Wed), 20:36 +0100, Michael Walle:
> Hi,
> 
> > Currently, we are supporting block protection only for
> > flash chips with 3 block protection bits in the SR register.
> > This patch enables block protection support for some flash with
> > 4 block protection bits(bp0-3).
> > 
> > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> > ---
> > v3 :
> >   Fix wrong ofs calculation on v2 patch
> > v2 :
> >   Add sample table portion about 4bit block protection on the
> > comment
> >   Trivial coding style change
> > 
> >  drivers/mtd/spi-nor/spi-nor.c | 127 +++++++++++++++++++++++++++++-
> > ----
> >  include/linux/mtd/spi-nor.h   |   8 +++
> >  2 files changed, 119 insertions(+), 16 deletions(-)
> > 
> > diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-
> > nor/spi-nor.c
> > index e3da6a8654a8..7e8af6c4fdfa 100644
> > --- a/drivers/mtd/spi-nor/spi-nor.c
> > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > @@ -238,6 +238,14 @@ struct flash_info {
> >  					 * status register. Must be
> > used with
> >  					 * SPI_NOR_HAS_TB.
> >  					 */
> > +#define SPI_NOR_HAS_BP3		BIT(17)	/*
> > +					 * Flash SR has 4 bit fields
> > (BP0-3)
> > +					 * for block protection.
> > +					 */
> > +#define SPI_NOR_BP3_SR_BIT6	BIT(18)	/*
> > +					 * BP3 is bit 6 of status
> > register.
> > +					 * Must be used with
> > SPI_NOR_HAS_BP3.
> > +					 */
> >  
> >  	/* Part specific fixup hooks. */
> >  	const struct spi_nor_fixups *fixups;
> > @@ -1767,23 +1775,47 @@ static void stm_get_locked_range(struct
> > spi_nor *nor, u8 sr, loff_t *ofs,
> >  	struct mtd_info *mtd = &nor->mtd;
> >  	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
> >  	u8 tb_mask = SR_TB_BIT5;
> > -	int pow;
> > +	u8 bp;
> > +	int pow = 0;
> >  
> >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> >  		tb_mask = SR_TB_BIT6;
> >  
> > -	if (!(sr & mask)) {
> > -		/* No protection */
> > -		*ofs = 0;
> > -		*len = 0;
> > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > +		u8 tmp;
> > +
> > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
> > +			tmp = sr & (mask | SR_BP3_BIT6);
> > +		else
> > +			tmp = sr & (mask | SR_BP3_BIT5);
> > +
> > +		if (tmp & SR_BP3_BIT6)
> > +			tmp = (tmp & ~BIT(6)) | BIT(5);
> > +
> > +		bp = tmp >> SR_BP_SHIFT;
> > +		if (!bp) {
> > +			*ofs = 0;
> > +			*len = 0;
> > +			return;
> > +		}
> > +		if (bp <= ilog2(nor->n_sectors))
> > +			pow = ilog2(nor->n_sectors) + 1 - bp;
> >  	} else {
> > -		pow = ((sr & mask) ^ mask) >> SR_BP_SHIFT;
> > -		*len = mtd->size >> pow;
> > -		if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
> > +		bp = (sr & mask) >> SR_BP_SHIFT;
> > +		if (!bp) {
> >  			*ofs = 0;
> > -		else
> > -			*ofs = mtd->size - *len;
> > +			*len = 0;
> > +			return;
> > +		}
> > +		pow = bp ^ (mask >> SR_BP_SHIFT);
> >  	}
> > +
> > +	*len = mtd->size >> pow;
> > +
> > +	if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
> > +		*ofs = 0;
> > +	else
> > +		*ofs = mtd->size - *len;
> >  }
> >  
> >  /*
> > @@ -1823,7 +1855,7 @@ static int stm_is_unlocked_sr(struct spi_nor
> > *nor, loff_t ofs, uint64_t len,
> >  
> >  /*
> >   * Lock a region of the flash. Compatible with ST Micro and
> > similar flash.
> > - * Supports the block protection bits BP{0,1,2} in the status
> > register
> > + * Supports the block protection bits BP{0,1,2,3} in the status
> > register
> >   * (SR). Does not support these features found in newer SR
> > bitfields:
> >   *   - SEC: sector/block protect - only handle SEC=0 (block
> > protect)
> >   *   - CMP: complement protect - only support CMP=0 (range is not
> > complemented)
> > @@ -1831,7 +1863,7 @@ static int stm_is_unlocked_sr(struct spi_nor
> > *nor, loff_t ofs, uint64_t len,
> >   * Support for the following is provided conditionally for some
> > flash:
> >   *   - TB: top/bottom protect
> >   *
> > - * Sample table portion for 8MB flash (Winbond w25q64fw):
> > + * Sample table portion for 8MB flash (Winbond w25q64fw / BP0-2):
> >   *
> >   *   SEC  |  TB   |  BP2  |  BP1  |  BP0  |  Prot Length  |
> > Protected Portion
> >   *  ------------------------------------------------------------
> > --------------
> > @@ -1851,6 +1883,32 @@ static int stm_is_unlocked_sr(struct spi_nor
> > *nor, loff_t ofs, uint64_t len,
> >   *    0   |   1   |   1   |   0   |   1   |  2 MB         | Lower
> > 1/4
> >   *    0   |   1   |   1   |   1   |   0   |  4 MB         | Lower
> > 1/2
> >   *
> > + * Sample table portion for 64MB flash (Micron n25q512ax3 / BP0-
> > 3):
> > + *
> > + *   TB   |  BP3  |  BP2  |  BP1  |  BP0  |  Prot Length  |
> > Protected Portion
> > + *  ------------------------------------------------------------
> > --------------
> > + *    0   |   0   |   0   |   0   |   0   |  NONE         | NONE
> > + *    0   |   0   |   0   |   0   |   1   |   64 KB       | Upper
> > 1/1024
> > + *    0   |   0   |   0   |   1   |   0   |  128 KB       | Upper
> > 1/512
> > + *    0   |   0   |   0   |   1   |   1   |  256 KB       | Upper
> > 1/256
> > + *   ...
> > + *    0   |   1   |   0   |   0   |   1   |  16 MB        | Upper
> > 1/4
> > + *    0   |   1   |   0   |   1   |   0   |  32 MB        | Upper
> > 1/2
> > + *    0   |   1   |   0   |   1   |   1   |  64 MB        | ALL
> > + *    0   |   1   |   1   |   0   |   0   |  64 MB        | ALL
> > + *   ...
> > + *  ------|-------|-------|-------|-------|---------------|-------
> > ------------
> > + *    1   |   0   |   0   |   0   |   0   |   NONE        | NONE
> > + *    1   |   0   |   0   |   0   |   1   |   64 KB       | Lower
> > 1/1024
> > + *    1   |   0   |   0   |   1   |   0   |  128 KB       | Lower
> > 1/512
> > + *    1   |   0   |   0   |   1   |   1   |  256 KB       | Lower
> > 1/256
> > + *   ...
> > + *    1   |   1   |   0   |   0   |   1   |  16 MB        | Lower
> > 1/4
> > + *    1   |   1   |   0   |   1   |   0   |  32 MB        | Lower
> > 1/2
> > + *    1   |   1   |   0   |   1   |   1   |  64 MB        | ALL
> > + *    1   |   1   |   1   |   0   |   0   |  64 MB        | ALL
> > + *   ...
> > + *
> >   * Returns negative on errors, 0 on success.
> >   */
> >  static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
> > @@ -1898,6 +1956,12 @@ static int stm_lock(struct spi_nor *nor,
> > loff_t ofs, uint64_t len)
> >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> >  		tb_mask = SR_TB_BIT6;
> >  
> > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
> > +			mask = mask | SR_BP3_BIT6;
> > +		else
> > +			mask = mask | SR_BP3_BIT5;
> > +	}
> >  	/*
> >  	 * Need smallest pow such that:
> >  	 *
> > @@ -1908,7 +1972,17 @@ static int stm_lock(struct spi_nor *nor,
> > loff_t ofs, uint64_t len)
> >  	 *   pow = ceil(log2(size / len)) = log2(size) -
> > floor(log2(len))
> >  	 */
> >  	pow = ilog2(mtd->size) - ilog2(lock_len);
> > -	val = mask - (pow << SR_BP_SHIFT);
> > +
> > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > +		val = ilog2(nor->n_sectors) + 1 - pow;
> 
> Why do you use a new calculation here? As far as I can see, the
> method is
> the same except that is has one bit more. That also raises the
> question why
> n_sectors is now needed?
> 
> Can't we just initialize the mask with
> 
> mask = SR_BP2 | SR_BP1 | SR_BP0;
> if (nor->flags & SNOR_F_HAS_SR_BP3)
>     mask |= SR_BP3_BIT5;
> 
> do the calculation and checks and then move the SR_BP3_BIT5 to
> SR_BP3_BIT6
> if SNOR_F_HAS_SR_BP3_BIT6 is set.
> 

For most of flashes that supporting BP0-2, the smallest protected
portion is fixed as 1/64 and it can be properly handled by existing
calculation. (Actually it's not fully generic, see flashes like
w25q40bw or m25p80. Of course, it doesn't have SPI_NOR_HAS_LOCK flag
even though it has BP0-2 bit in SR)

We need new calculation method for 4bit block protection and for making
it more generic, I choose n_sectors.

On all the flashes I checked, n_sectors is proper value for getting
block protected portion.

		density	portion	n_sectors
W25M512JV	64MB	1/512	512
N25Q128A	16MB	1/256	256	
N25Q512A	64MB	1/1024	1024
MT25QL02GCBB	256MB	1/4096	4096

> > +		val = val << SR_BP_SHIFT;
> > +
> > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
> > +			val = (val & ~BIT(5)) | BIT(6);
> > +	} else {
> > +		val = mask - (pow << SR_BP_SHIFT);
> > +	}
> > +
> >  	if (val & ~mask)
> >  		return -EINVAL;
> >  	/* Don't "lock" with no region! */
> > @@ -1983,6 +2057,13 @@ static int stm_unlock(struct spi_nor *nor,
> > loff_t ofs, uint64_t len)
> >  
> >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> >  		tb_mask = SR_TB_BIT6;
> > +
> > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
> > +			mask = mask | SR_BP3_BIT6;
> > +		else
> > +			mask = mask | SR_BP3_BIT5;
> > +	}
> >  	/*
> >  	 * Need largest pow such that:
> >  	 *
> > @@ -1995,13 +2076,20 @@ static int stm_unlock(struct spi_nor *nor,
> > loff_t ofs, uint64_t len)
> >  	pow = ilog2(mtd->size) - order_base_2(lock_len);
> >  	if (lock_len == 0) {
> >  		val = 0; /* fully unlocked */
> > +	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > +		val = ilog2(nor->n_sectors) + 1 - pow;
> > +		val = val << SR_BP_SHIFT;
> > +
> > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
> > +			val = (val & ~BIT(5)) | BIT(6);
> >  	} else {
> >  		val = mask - (pow << SR_BP_SHIFT);
> > -		/* Some power-of-two sizes are not supported */
> > -		if (val & ~mask)
> > -			return -EINVAL;
> >  	}
> >  
> > +	/* Some power-of-two sizes are not supported */
> > +	if (val & ~mask)
> > +		return -EINVAL;
> > +
> >  	status_new = (status_old & ~mask & ~tb_mask) | val;
> >  
> >  	/* Don't protect status register if we're fully unlocked */
> > @@ -4736,6 +4824,7 @@ static void spi_nor_info_init_params(struct
> > spi_nor *nor)
> >  	/* Set SPI NOR sizes. */
> >  	params->size = (u64)info->sector_size * info->n_sectors;
> >  	params->page_size = info->page_size;
> > +	params->n_sectors = info->n_sectors;
> >  
> >  	if (!(info->flags & SPI_NOR_NO_FR)) {
> >  		/* Default to Fast Read for DT and non-DT platform
> > devices. */
> > @@ -5192,6 +5281,11 @@ int spi_nor_scan(struct spi_nor *nor, const
> > char *name,
> >  		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
> >  	if (info->flags & USE_CLSR)
> >  		nor->flags |= SNOR_F_USE_CLSR;
> > +	if (info->flags & SPI_NOR_HAS_BP3) {
> > +		nor->flags |= SNOR_F_HAS_SR_BP3;
> > +		if (info->flags & SPI_NOR_BP3_SR_BIT6)
> > +			nor->flags |= SNOR_F_HAS_SR_BP3_BIT6;
> > +	}
> >  
> >  	if (info->flags & SPI_NOR_NO_ERASE)
> >  		mtd->flags |= MTD_NO_ERASE;
> > @@ -5199,6 +5293,7 @@ int spi_nor_scan(struct spi_nor *nor, const
> > char *name,
> >  	mtd->dev.parent = dev;
> >  	nor->page_size = params->page_size;
> >  	mtd->writebufsize = nor->page_size;
> > +	nor->n_sectors = params->n_sectors;
> >  
> >  	if (of_property_read_bool(np, "broken-flash-reset"))
> >  		nor->flags |= SNOR_F_BROKEN_RESET;
> > diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-
> > nor.h
> > index 541c06d042e8..92d550501daf 100644
> > --- a/include/linux/mtd/spi-nor.h
> > +++ b/include/linux/mtd/spi-nor.h
> > @@ -129,7 +129,9 @@
> >  #define SR_BP1			BIT(3)	/* Block protect 1
> > */
> >  #define SR_BP2			BIT(4)	/* Block protect 2
> > */
> >  #define SR_TB_BIT5		BIT(5)	/* Top/Bottom protect */
> > +#define SR_BP3_BIT5		BIT(5)	/* Block protect 3
> > */
> 
> maybe just name it SR_BP3? would also be more consistent with the
> proposal
> above.
> 
> >  #define SR_TB_BIT6		BIT(6)	/* Top/Bottom protect */
> > +#define SR_BP3_BIT6		BIT(6)	/* Block protect 3
> > */
> >  #define SR_SRWD			BIT(7)	/* SR write protect
> > */
> >  /* Spansion/Cypress specific status bits */
> >  #define SR_E_ERR		BIT(5)
> > @@ -248,6 +250,8 @@ enum spi_nor_option_flags {
> >  	SNOR_F_HAS_16BIT_SR	= BIT(9),
> >  	SNOR_F_NO_READ_CR	= BIT(10),
> >  	SNOR_F_HAS_SR_TB_BIT6	= BIT(11),
> > +	SNOR_F_HAS_SR_BP3	= BIT(12),
> > +	SNOR_F_HAS_SR_BP3_BIT6	= BIT(13),
> >  
> >  };
> >  
> > @@ -519,6 +523,7 @@ struct spi_nor_locking_ops {
> >   *
> >   * @size:		the flash memory density in bytes.
> >   * @page_size:		the page size of the SPI NOR flash
> > memory.
> > + * @n_sectors:		number of sectors
> >   * @hwcaps:		describes the read and page program
> > hardware
> >   *			capabilities.
> >   * @reads:		read capabilities ordered by priority: the
> > higher index
> > @@ -541,6 +546,7 @@ struct spi_nor_locking_ops {
> >  struct spi_nor_flash_parameter {
> >  	u64				size;
> >  	u32				page_size;
> > +	u16				n_sectors;
> >  
> >  	struct spi_nor_hwcaps		hwcaps;
> >  	struct spi_nor_read_command	reads[SNOR_CMD_READ_MAX];
> > @@ -573,6 +579,7 @@ struct flash_info;
> >   * @bouncebuf_size:	size of the bounce buffer
> >   * @info:		spi-nor part JDEC MFR id and other info
> >   * @page_size:		the page size of the SPI NOR
> > + * @n_sector:		number of sectors
> >   * @addr_width:		number of address bytes
> >   * @erase_opcode:	the opcode for erasing a sector
> >   * @read_opcode:	the read opcode
> > @@ -599,6 +606,7 @@ struct spi_nor {
> >  	size_t			bouncebuf_size;
> >  	const struct flash_info	*info;
> >  	u32			page_size;
> > +	u16			n_sectors;
> >  	u8			addr_width;
> >  	u8			erase_opcode;
> >  	u8			read_opcode;
> > -- 
> > 2.17.1
> > 
> > 
> > ______________________________________________________
> > Linux MTD discussion mailing list
> > 
https://protect2.fireeye.com/url?k=06b6dd5d-5b7d5a63-06b75612-0cc47a31309a-83164929001f7741&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
> > 
> 
> 


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Hi Jungseung,

Am 2020-01-23 07:22, schrieb Jungseung Lee:
> Hi, Michael
> 
> 2020-01-22 (Wed), 20:36 +0100, Michael Walle:
>> Hi,
>> 
>> > Currently, we are supporting block protection only for
>> > flash chips with 3 block protection bits in the SR register.
>> > This patch enables block protection support for some flash with
>> > 4 block protection bits(bp0-3).
>> >
>> > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
>> > ---
>> > v3 :
>> >   Fix wrong ofs calculation on v2 patch
>> > v2 :
>> >   Add sample table portion about 4bit block protection on the
>> > comment
>> >   Trivial coding style change
>> >
>> >  drivers/mtd/spi-nor/spi-nor.c | 127 +++++++++++++++++++++++++++++-
>> > ----
>> >  include/linux/mtd/spi-nor.h   |   8 +++
>> >  2 files changed, 119 insertions(+), 16 deletions(-)
>> >
>> > diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-
>> > nor/spi-nor.c
>> > index e3da6a8654a8..7e8af6c4fdfa 100644
>> > --- a/drivers/mtd/spi-nor/spi-nor.c
>> > +++ b/drivers/mtd/spi-nor/spi-nor.c
>> > @@ -238,6 +238,14 @@ struct flash_info {
>> >  					 * status register. Must be
>> > used with
>> >  					 * SPI_NOR_HAS_TB.
>> >  					 */
>> > +#define SPI_NOR_HAS_BP3		BIT(17)	/*
>> > +					 * Flash SR has 4 bit fields
>> > (BP0-3)
>> > +					 * for block protection.
>> > +					 */
>> > +#define SPI_NOR_BP3_SR_BIT6	BIT(18)	/*
>> > +					 * BP3 is bit 6 of status
>> > register.
>> > +					 * Must be used with
>> > SPI_NOR_HAS_BP3.
>> > +					 */
>> >
>> >  	/* Part specific fixup hooks. */
>> >  	const struct spi_nor_fixups *fixups;
>> > @@ -1767,23 +1775,47 @@ static void stm_get_locked_range(struct
>> > spi_nor *nor, u8 sr, loff_t *ofs,
>> >  	struct mtd_info *mtd = &nor->mtd;
>> >  	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
>> >  	u8 tb_mask = SR_TB_BIT5;
>> > -	int pow;
>> > +	u8 bp;
>> > +	int pow = 0;
>> >
>> >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>> >  		tb_mask = SR_TB_BIT6;
>> >
>> > -	if (!(sr & mask)) {
>> > -		/* No protection */
>> > -		*ofs = 0;
>> > -		*len = 0;
>> > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > +		u8 tmp;
>> > +
>> > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
>> > +			tmp = sr & (mask | SR_BP3_BIT6);
>> > +		else
>> > +			tmp = sr & (mask | SR_BP3_BIT5);
>> > +
>> > +		if (tmp & SR_BP3_BIT6)
>> > +			tmp = (tmp & ~BIT(6)) | BIT(5);
>> > +
>> > +		bp = tmp >> SR_BP_SHIFT;
>> > +		if (!bp) {
>> > +			*ofs = 0;
>> > +			*len = 0;
>> > +			return;
>> > +		}
>> > +		if (bp <= ilog2(nor->n_sectors))
>> > +			pow = ilog2(nor->n_sectors) + 1 - bp;
>> >  	} else {
>> > -		pow = ((sr & mask) ^ mask) >> SR_BP_SHIFT;
>> > -		*len = mtd->size >> pow;
>> > -		if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
>> > +		bp = (sr & mask) >> SR_BP_SHIFT;
>> > +		if (!bp) {
>> >  			*ofs = 0;
>> > -		else
>> > -			*ofs = mtd->size - *len;
>> > +			*len = 0;
>> > +			return;
>> > +		}
>> > +		pow = bp ^ (mask >> SR_BP_SHIFT);
>> >  	}
>> > +
>> > +	*len = mtd->size >> pow;
>> > +
>> > +	if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
>> > +		*ofs = 0;
>> > +	else
>> > +		*ofs = mtd->size - *len;
>> >  }
>> >
>> >  /*
>> > @@ -1823,7 +1855,7 @@ static int stm_is_unlocked_sr(struct spi_nor
>> > *nor, loff_t ofs, uint64_t len,
>> >
>> >  /*
>> >   * Lock a region of the flash. Compatible with ST Micro and
>> > similar flash.
>> > - * Supports the block protection bits BP{0,1,2} in the status
>> > register
>> > + * Supports the block protection bits BP{0,1,2,3} in the status
>> > register
>> >   * (SR). Does not support these features found in newer SR
>> > bitfields:
>> >   *   - SEC: sector/block protect - only handle SEC=0 (block
>> > protect)
>> >   *   - CMP: complement protect - only support CMP=0 (range is not
>> > complemented)
>> > @@ -1831,7 +1863,7 @@ static int stm_is_unlocked_sr(struct spi_nor
>> > *nor, loff_t ofs, uint64_t len,
>> >   * Support for the following is provided conditionally for some
>> > flash:
>> >   *   - TB: top/bottom protect
>> >   *
>> > - * Sample table portion for 8MB flash (Winbond w25q64fw):
>> > + * Sample table portion for 8MB flash (Winbond w25q64fw / BP0-2):
>> >   *
>> >   *   SEC  |  TB   |  BP2  |  BP1  |  BP0  |  Prot Length  |
>> > Protected Portion
>> >   *  ------------------------------------------------------------
>> > --------------
>> > @@ -1851,6 +1883,32 @@ static int stm_is_unlocked_sr(struct spi_nor
>> > *nor, loff_t ofs, uint64_t len,
>> >   *    0   |   1   |   1   |   0   |   1   |  2 MB         | Lower
>> > 1/4
>> >   *    0   |   1   |   1   |   1   |   0   |  4 MB         | Lower
>> > 1/2
>> >   *
>> > + * Sample table portion for 64MB flash (Micron n25q512ax3 / BP0-
>> > 3):
>> > + *
>> > + *   TB   |  BP3  |  BP2  |  BP1  |  BP0  |  Prot Length  |
>> > Protected Portion
>> > + *  ------------------------------------------------------------
>> > --------------
>> > + *    0   |   0   |   0   |   0   |   0   |  NONE         | NONE
>> > + *    0   |   0   |   0   |   0   |   1   |   64 KB       | Upper
>> > 1/1024
>> > + *    0   |   0   |   0   |   1   |   0   |  128 KB       | Upper
>> > 1/512
>> > + *    0   |   0   |   0   |   1   |   1   |  256 KB       | Upper
>> > 1/256
>> > + *   ...
>> > + *    0   |   1   |   0   |   0   |   1   |  16 MB        | Upper
>> > 1/4
>> > + *    0   |   1   |   0   |   1   |   0   |  32 MB        | Upper
>> > 1/2
>> > + *    0   |   1   |   0   |   1   |   1   |  64 MB        | ALL
>> > + *    0   |   1   |   1   |   0   |   0   |  64 MB        | ALL
>> > + *   ...
>> > + *  ------|-------|-------|-------|-------|---------------|-------
>> > ------------
>> > + *    1   |   0   |   0   |   0   |   0   |   NONE        | NONE
>> > + *    1   |   0   |   0   |   0   |   1   |   64 KB       | Lower
>> > 1/1024
>> > + *    1   |   0   |   0   |   1   |   0   |  128 KB       | Lower
>> > 1/512
>> > + *    1   |   0   |   0   |   1   |   1   |  256 KB       | Lower
>> > 1/256
>> > + *   ...
>> > + *    1   |   1   |   0   |   0   |   1   |  16 MB        | Lower
>> > 1/4
>> > + *    1   |   1   |   0   |   1   |   0   |  32 MB        | Lower
>> > 1/2
>> > + *    1   |   1   |   0   |   1   |   1   |  64 MB        | ALL
>> > + *    1   |   1   |   1   |   0   |   0   |  64 MB        | ALL
>> > + *   ...
>> > + *
>> >   * Returns negative on errors, 0 on success.
>> >   */
>> >  static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
>> > @@ -1898,6 +1956,12 @@ static int stm_lock(struct spi_nor *nor,
>> > loff_t ofs, uint64_t len)
>> >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>> >  		tb_mask = SR_TB_BIT6;
>> >
>> > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
>> > +			mask = mask | SR_BP3_BIT6;
>> > +		else
>> > +			mask = mask | SR_BP3_BIT5;
>> > +	}
>> >  	/*
>> >  	 * Need smallest pow such that:
>> >  	 *
>> > @@ -1908,7 +1972,17 @@ static int stm_lock(struct spi_nor *nor,
>> > loff_t ofs, uint64_t len)
>> >  	 *   pow = ceil(log2(size / len)) = log2(size) -
>> > floor(log2(len))
>> >  	 */
>> >  	pow = ilog2(mtd->size) - ilog2(lock_len);
>> > -	val = mask - (pow << SR_BP_SHIFT);
>> > +
>> > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > +		val = ilog2(nor->n_sectors) + 1 - pow;
>> 
>> Why do you use a new calculation here? As far as I can see, the
>> method is
>> the same except that is has one bit more. That also raises the
>> question why
>> n_sectors is now needed?
>> 
>> Can't we just initialize the mask with
>> 
>> mask = SR_BP2 | SR_BP1 | SR_BP0;
>> if (nor->flags & SNOR_F_HAS_SR_BP3)
>>     mask |= SR_BP3_BIT5;
>> 
>> do the calculation and checks and then move the SR_BP3_BIT5 to
>> SR_BP3_BIT6
>> if SNOR_F_HAS_SR_BP3_BIT6 is set.
>> 
> 
> For most of flashes that supporting BP0-2, the smallest protected
> portion is fixed as 1/64
> and it can be properly handled by existing
> calculation. (Actually it's not fully generic, see flashes like
> w25q40bw or m25p80. Of course, it doesn't have SPI_NOR_HAS_LOCK flag
> even though it has BP0-2 bit in SR)

No. The rules are always the same wether there are three or four BP
bits (the example in stm_lock() has not enough information on this):

(1) the first setting (besides 0) protects one sector. The second
     protects 2, the third 4 and so on. eg 2^N
(2) the last setting is _always_ protect all, just like the '0' setting
     is always protect none.
(3) if there is an overflow because there are no more free slots for
     further settings (for 3 bits with flashes > 32MBit, for 4
     bits if should be flashes > 16GBit), the first entry will be
     discarded (eg the very first is the "just one sector" entry).

This is true for all flashes which uses this kind of setting, have a
look at the m25p80 or w25q40bw, these are no exception. It is just the
notation "lower 1/64" which is only true for flashes which either
overflows in (3) or fill all entries (eg. with 3bits that would be the
32Mbit version).

So for the 3 bit case the following flashes are border cases:
  - 16mbit (less settings than slots)
  - 32mbit (number of settings and free slots match)
  - 64mbit (more settings than slots, first setting is discarded)

That being said, I suspect all the 16mbit flashes (and below) which have
the _LOCK bit set are broken, because the entries has to be shifted. 
I'll
look into that later. This is the same "issue" you have with the 4 bits.
So if this is fixed, you should not need another formula for the 4 bit
case.

> We need new calculation method for 4bit block protection and for making
> it more generic, I choose n_sectors.
> 
> On all the flashes I checked, n_sectors is proper value for getting
> block protected portion.
> 
> 		density	portion	n_sectors
> W25M512JV	64MB	1/512	512
> N25Q128A	16MB	1/256	256
> N25Q512A	64MB	1/1024	1024
> MT25QL02GCBB	256MB	1/4096	4096

The rules above apply to these flashes, too. Could you double check 
that?

-michael

> 
>> > +		val = val << SR_BP_SHIFT;
>> > +
>> > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
>> > +			val = (val & ~BIT(5)) | BIT(6);
>> > +	} else {
>> > +		val = mask - (pow << SR_BP_SHIFT);
>> > +	}
>> > +
>> >  	if (val & ~mask)
>> >  		return -EINVAL;
>> >  	/* Don't "lock" with no region! */
>> > @@ -1983,6 +2057,13 @@ static int stm_unlock(struct spi_nor *nor,
>> > loff_t ofs, uint64_t len)
>> >
>> >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>> >  		tb_mask = SR_TB_BIT6;
>> > +
>> > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
>> > +			mask = mask | SR_BP3_BIT6;
>> > +		else
>> > +			mask = mask | SR_BP3_BIT5;
>> > +	}
>> >  	/*
>> >  	 * Need largest pow such that:
>> >  	 *
>> > @@ -1995,13 +2076,20 @@ static int stm_unlock(struct spi_nor *nor,
>> > loff_t ofs, uint64_t len)
>> >  	pow = ilog2(mtd->size) - order_base_2(lock_len);
>> >  	if (lock_len == 0) {
>> >  		val = 0; /* fully unlocked */
>> > +	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > +		val = ilog2(nor->n_sectors) + 1 - pow;
>> > +		val = val << SR_BP_SHIFT;
>> > +
>> > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
>> > +			val = (val & ~BIT(5)) | BIT(6);
>> >  	} else {
>> >  		val = mask - (pow << SR_BP_SHIFT);
>> > -		/* Some power-of-two sizes are not supported */
>> > -		if (val & ~mask)
>> > -			return -EINVAL;
>> >  	}
>> >
>> > +	/* Some power-of-two sizes are not supported */
>> > +	if (val & ~mask)
>> > +		return -EINVAL;
>> > +
>> >  	status_new = (status_old & ~mask & ~tb_mask) | val;
>> >
>> >  	/* Don't protect status register if we're fully unlocked */
>> > @@ -4736,6 +4824,7 @@ static void spi_nor_info_init_params(struct
>> > spi_nor *nor)
>> >  	/* Set SPI NOR sizes. */
>> >  	params->size = (u64)info->sector_size * info->n_sectors;
>> >  	params->page_size = info->page_size;
>> > +	params->n_sectors = info->n_sectors;
>> >
>> >  	if (!(info->flags & SPI_NOR_NO_FR)) {
>> >  		/* Default to Fast Read for DT and non-DT platform
>> > devices. */
>> > @@ -5192,6 +5281,11 @@ int spi_nor_scan(struct spi_nor *nor, const
>> > char *name,
>> >  		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
>> >  	if (info->flags & USE_CLSR)
>> >  		nor->flags |= SNOR_F_USE_CLSR;
>> > +	if (info->flags & SPI_NOR_HAS_BP3) {
>> > +		nor->flags |= SNOR_F_HAS_SR_BP3;
>> > +		if (info->flags & SPI_NOR_BP3_SR_BIT6)
>> > +			nor->flags |= SNOR_F_HAS_SR_BP3_BIT6;
>> > +	}
>> >
>> >  	if (info->flags & SPI_NOR_NO_ERASE)
>> >  		mtd->flags |= MTD_NO_ERASE;
>> > @@ -5199,6 +5293,7 @@ int spi_nor_scan(struct spi_nor *nor, const
>> > char *name,
>> >  	mtd->dev.parent = dev;
>> >  	nor->page_size = params->page_size;
>> >  	mtd->writebufsize = nor->page_size;
>> > +	nor->n_sectors = params->n_sectors;
>> >
>> >  	if (of_property_read_bool(np, "broken-flash-reset"))
>> >  		nor->flags |= SNOR_F_BROKEN_RESET;
>> > diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-
>> > nor.h
>> > index 541c06d042e8..92d550501daf 100644
>> > --- a/include/linux/mtd/spi-nor.h
>> > +++ b/include/linux/mtd/spi-nor.h
>> > @@ -129,7 +129,9 @@
>> >  #define SR_BP1			BIT(3)	/* Block protect 1
>> > */
>> >  #define SR_BP2			BIT(4)	/* Block protect 2
>> > */
>> >  #define SR_TB_BIT5		BIT(5)	/* Top/Bottom protect */
>> > +#define SR_BP3_BIT5		BIT(5)	/* Block protect 3
>> > */
>> 
>> maybe just name it SR_BP3? would also be more consistent with the
>> proposal
>> above.
>> 
>> >  #define SR_TB_BIT6		BIT(6)	/* Top/Bottom protect */
>> > +#define SR_BP3_BIT6		BIT(6)	/* Block protect 3
>> > */
>> >  #define SR_SRWD			BIT(7)	/* SR write protect
>> > */
>> >  /* Spansion/Cypress specific status bits */
>> >  #define SR_E_ERR		BIT(5)
>> > @@ -248,6 +250,8 @@ enum spi_nor_option_flags {
>> >  	SNOR_F_HAS_16BIT_SR	= BIT(9),
>> >  	SNOR_F_NO_READ_CR	= BIT(10),
>> >  	SNOR_F_HAS_SR_TB_BIT6	= BIT(11),
>> > +	SNOR_F_HAS_SR_BP3	= BIT(12),
>> > +	SNOR_F_HAS_SR_BP3_BIT6	= BIT(13),
>> >
>> >  };
>> >
>> > @@ -519,6 +523,7 @@ struct spi_nor_locking_ops {
>> >   *
>> >   * @size:		the flash memory density in bytes.
>> >   * @page_size:		the page size of the SPI NOR flash
>> > memory.
>> > + * @n_sectors:		number of sectors
>> >   * @hwcaps:		describes the read and page program
>> > hardware
>> >   *			capabilities.
>> >   * @reads:		read capabilities ordered by priority: the
>> > higher index
>> > @@ -541,6 +546,7 @@ struct spi_nor_locking_ops {
>> >  struct spi_nor_flash_parameter {
>> >  	u64				size;
>> >  	u32				page_size;
>> > +	u16				n_sectors;
>> >
>> >  	struct spi_nor_hwcaps		hwcaps;
>> >  	struct spi_nor_read_command	reads[SNOR_CMD_READ_MAX];
>> > @@ -573,6 +579,7 @@ struct flash_info;
>> >   * @bouncebuf_size:	size of the bounce buffer
>> >   * @info:		spi-nor part JDEC MFR id and other info
>> >   * @page_size:		the page size of the SPI NOR
>> > + * @n_sector:		number of sectors
>> >   * @addr_width:		number of address bytes
>> >   * @erase_opcode:	the opcode for erasing a sector
>> >   * @read_opcode:	the read opcode
>> > @@ -599,6 +606,7 @@ struct spi_nor {
>> >  	size_t			bouncebuf_size;
>> >  	const struct flash_info	*info;
>> >  	u32			page_size;
>> > +	u16			n_sectors;
>> >  	u8			addr_width;
>> >  	u8			erase_opcode;
>> >  	u8			read_opcode;
>> > --
>> > 2.17.1
>> >
>> >
>> > ______________________________________________________
>> > Linux MTD discussion mailing list
>> >
> https://protect2.fireeye.com/url?k=06b6dd5d-5b7d5a63-06b75612-0cc47a31309a-83164929001f7741&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
>> >
>> 
>> 

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Hi, Michael

2020-01-23 (Thu), 09:10 +0100, Michael Walle:
> Hi Jungseung,
> 
> Am 2020-01-23 07:22, schrieb Jungseung Lee:
> > Hi, Michael
> > 
> > 2020-01-22 (Wed), 20:36 +0100, Michael Walle:
> > > Hi,
> > > 
> > > > Currently, we are supporting block protection only for
> > > > flash chips with 3 block protection bits in the SR register.
> > > > This patch enables block protection support for some flash with
> > > > 4 block protection bits(bp0-3).
> > > > 
> > > > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> > > > ---
> > > > v3 :
> > > >   Fix wrong ofs calculation on v2 patch
> > > > v2 :
> > > >   Add sample table portion about 4bit block protection on the
> > > > comment
> > > >   Trivial coding style change
> > > > 
> > > >  drivers/mtd/spi-nor/spi-nor.c | 127
> > > > +++++++++++++++++++++++++++++-
> > > > ----
> > > >  include/linux/mtd/spi-nor.h   |   8 +++
> > > >  2 files changed, 119 insertions(+), 16 deletions(-)
> > > > 
> > > > diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-
> > > > nor/spi-nor.c
> > > > index e3da6a8654a8..7e8af6c4fdfa 100644
> > > > --- a/drivers/mtd/spi-nor/spi-nor.c
> > > > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > > > @@ -238,6 +238,14 @@ struct flash_info {
> > > >  					 * status register.
> > > > Must be
> > > > used with
> > > >  					 * SPI_NOR_HAS_TB.
> > > >  					 */
> > > > +#define SPI_NOR_HAS_BP3		BIT(17)	/*
> > > > +					 * Flash SR has 4 bit
> > > > fields
> > > > (BP0-3)
> > > > +					 * for block
> > > > protection.
> > > > +					 */
> > > > +#define SPI_NOR_BP3_SR_BIT6	BIT(18)	/*
> > > > +					 * BP3 is bit 6 of
> > > > status
> > > > register.
> > > > +					 * Must be used with
> > > > SPI_NOR_HAS_BP3.
> > > > +					 */
> > > > 
> > > >  	/* Part specific fixup hooks. */
> > > >  	const struct spi_nor_fixups *fixups;
> > > > @@ -1767,23 +1775,47 @@ static void stm_get_locked_range(struct
> > > > spi_nor *nor, u8 sr, loff_t *ofs,
> > > >  	struct mtd_info *mtd = &nor->mtd;
> > > >  	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
> > > >  	u8 tb_mask = SR_TB_BIT5;
> > > > -	int pow;
> > > > +	u8 bp;
> > > > +	int pow = 0;
> > > > 
> > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> > > >  		tb_mask = SR_TB_BIT6;
> > > > 
> > > > -	if (!(sr & mask)) {
> > > > -		/* No protection */
> > > > -		*ofs = 0;
> > > > -		*len = 0;
> > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > +		u8 tmp;
> > > > +
> > > > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
> > > > +			tmp = sr & (mask | SR_BP3_BIT6);
> > > > +		else
> > > > +			tmp = sr & (mask | SR_BP3_BIT5);
> > > > +
> > > > +		if (tmp & SR_BP3_BIT6)
> > > > +			tmp = (tmp & ~BIT(6)) | BIT(5);
> > > > +
> > > > +		bp = tmp >> SR_BP_SHIFT;
> > > > +		if (!bp) {
> > > > +			*ofs = 0;
> > > > +			*len = 0;
> > > > +			return;
> > > > +		}
> > > > +		if (bp <= ilog2(nor->n_sectors))
> > > > +			pow = ilog2(nor->n_sectors) + 1 - bp;
> > > >  	} else {
> > > > -		pow = ((sr & mask) ^ mask) >> SR_BP_SHIFT;
> > > > -		*len = mtd->size >> pow;
> > > > -		if (nor->flags & SNOR_F_HAS_SR_TB && sr &
> > > > tb_mask)
> > > > +		bp = (sr & mask) >> SR_BP_SHIFT;
> > > > +		if (!bp) {
> > > >  			*ofs = 0;
> > > > -		else
> > > > -			*ofs = mtd->size - *len;
> > > > +			*len = 0;
> > > > +			return;
> > > > +		}
> > > > +		pow = bp ^ (mask >> SR_BP_SHIFT);
> > > >  	}
> > > > +
> > > > +	*len = mtd->size >> pow;
> > > > +
> > > > +	if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
> > > > +		*ofs = 0;
> > > > +	else
> > > > +		*ofs = mtd->size - *len;
> > > >  }
> > > > 
> > > >  /*
> > > > @@ -1823,7 +1855,7 @@ static int stm_is_unlocked_sr(struct
> > > > spi_nor
> > > > *nor, loff_t ofs, uint64_t len,
> > > > 
> > > >  /*
> > > >   * Lock a region of the flash. Compatible with ST Micro and
> > > > similar flash.
> > > > - * Supports the block protection bits BP{0,1,2} in the status
> > > > register
> > > > + * Supports the block protection bits BP{0,1,2,3} in the
> > > > status
> > > > register
> > > >   * (SR). Does not support these features found in newer SR
> > > > bitfields:
> > > >   *   - SEC: sector/block protect - only handle SEC=0 (block
> > > > protect)
> > > >   *   - CMP: complement protect - only support CMP=0 (range is
> > > > not
> > > > complemented)
> > > > @@ -1831,7 +1863,7 @@ static int stm_is_unlocked_sr(struct
> > > > spi_nor
> > > > *nor, loff_t ofs, uint64_t len,
> > > >   * Support for the following is provided conditionally for
> > > > some
> > > > flash:
> > > >   *   - TB: top/bottom protect
> > > >   *
> > > > - * Sample table portion for 8MB flash (Winbond w25q64fw):
> > > > + * Sample table portion for 8MB flash (Winbond w25q64fw / BP0-
> > > > 2):
> > > >   *
> > > >   *   SEC  |  TB   |  BP2  |  BP1  |  BP0  |  Prot Length  |
> > > > Protected Portion
> > > >   *  --------------------------------------------------------
> > > > ----
> > > > --------------
> > > > @@ -1851,6 +1883,32 @@ static int stm_is_unlocked_sr(struct
> > > > spi_nor
> > > > *nor, loff_t ofs, uint64_t len,
> > > >   *    0   |   1   |   1   |   0   |   1   |  2 MB         |
> > > > Lower
> > > > 1/4
> > > >   *    0   |   1   |   1   |   1   |   0   |  4 MB         |
> > > > Lower
> > > > 1/2
> > > >   *
> > > > + * Sample table portion for 64MB flash (Micron n25q512ax3 /
> > > > BP0-
> > > > 3):
> > > > + *
> > > > + *   TB   |  BP3  |  BP2  |  BP1  |  BP0  |  Prot Length  |
> > > > Protected Portion
> > > > + *  --------------------------------------------------------
> > > > ----
> > > > --------------
> > > > + *    0   |   0   |   0   |   0   |   0   |  NONE         |
> > > > NONE
> > > > + *    0   |   0   |   0   |   0   |   1   |   64 KB       |
> > > > Upper
> > > > 1/1024
> > > > + *    0   |   0   |   0   |   1   |   0   |  128 KB       |
> > > > Upper
> > > > 1/512
> > > > + *    0   |   0   |   0   |   1   |   1   |  256 KB       |
> > > > Upper
> > > > 1/256
> > > > + *   ...
> > > > + *    0   |   1   |   0   |   0   |   1   |  16 MB        |
> > > > Upper
> > > > 1/4
> > > > + *    0   |   1   |   0   |   1   |   0   |  32 MB        |
> > > > Upper
> > > > 1/2
> > > > + *    0   |   1   |   0   |   1   |   1   |  64 MB        |
> > > > ALL
> > > > + *    0   |   1   |   1   |   0   |   0   |  64 MB        |
> > > > ALL
> > > > + *   ...
> > > > + *  ------|-------|-------|-------|-------|---------------|---
> > > > ----
> > > > ------------
> > > > + *    1   |   0   |   0   |   0   |   0   |   NONE        |
> > > > NONE
> > > > + *    1   |   0   |   0   |   0   |   1   |   64 KB       |
> > > > Lower
> > > > 1/1024
> > > > + *    1   |   0   |   0   |   1   |   0   |  128 KB       |
> > > > Lower
> > > > 1/512
> > > > + *    1   |   0   |   0   |   1   |   1   |  256 KB       |
> > > > Lower
> > > > 1/256
> > > > + *   ...
> > > > + *    1   |   1   |   0   |   0   |   1   |  16 MB        |
> > > > Lower
> > > > 1/4
> > > > + *    1   |   1   |   0   |   1   |   0   |  32 MB        |
> > > > Lower
> > > > 1/2
> > > > + *    1   |   1   |   0   |   1   |   1   |  64 MB        |
> > > > ALL
> > > > + *    1   |   1   |   1   |   0   |   0   |  64 MB        |
> > > > ALL
> > > > + *   ...
> > > > + *
> > > >   * Returns negative on errors, 0 on success.
> > > >   */
> > > >  static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t
> > > > len)
> > > > @@ -1898,6 +1956,12 @@ static int stm_lock(struct spi_nor *nor,
> > > > loff_t ofs, uint64_t len)
> > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> > > >  		tb_mask = SR_TB_BIT6;
> > > > 
> > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
> > > > +			mask = mask | SR_BP3_BIT6;
> > > > +		else
> > > > +			mask = mask | SR_BP3_BIT5;
> > > > +	}
> > > >  	/*
> > > >  	 * Need smallest pow such that:
> > > >  	 *
> > > > @@ -1908,7 +1972,17 @@ static int stm_lock(struct spi_nor *nor,
> > > > loff_t ofs, uint64_t len)
> > > >  	 *   pow = ceil(log2(size / len)) = log2(size) -
> > > > floor(log2(len))
> > > >  	 */
> > > >  	pow = ilog2(mtd->size) - ilog2(lock_len);
> > > > -	val = mask - (pow << SR_BP_SHIFT);
> > > > +
> > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
> > > 
> > > Why do you use a new calculation here? As far as I can see, the
> > > method is
> > > the same except that is has one bit more. That also raises the
> > > question why
> > > n_sectors is now needed?
> > > 
> > > Can't we just initialize the mask with
> > > 
> > > mask = SR_BP2 | SR_BP1 | SR_BP0;
> > > if (nor->flags & SNOR_F_HAS_SR_BP3)
> > >     mask |= SR_BP3_BIT5;
> > > 
> > > do the calculation and checks and then move the SR_BP3_BIT5 to
> > > SR_BP3_BIT6
> > > if SNOR_F_HAS_SR_BP3_BIT6 is set.
> > > 
> > 
> > For most of flashes that supporting BP0-2, the smallest protected
> > portion is fixed as 1/64
> > and it can be properly handled by existing
> > calculation. (Actually it's not fully generic, see flashes like
> > w25q40bw or m25p80. Of course, it doesn't have SPI_NOR_HAS_LOCK
> > flag
> > even though it has BP0-2 bit in SR)
> 
> No. The rules are always the same wether there are three or four BP
> bits (the example in stm_lock() has not enough information on this):
> 
> (1) the first setting (besides 0) protects one sector. The second
>      protects 2, the third 4 and so on. eg 2^N
> (2) the last setting is _always_ protect all, just like the '0'
> setting
>      is always protect none.
> (3) if there is an overflow because there are no more free slots for
>      further settings (for 3 bits with flashes > 32MBit, for 4
>      bits if should be flashes > 16GBit), the first entry will be
>      discarded (eg the very first is the "just one sector" entry).
> 
> This is true for all flashes which uses this kind of setting, have a
> look at the m25p80 or w25q40bw, these are no exception. It is just
> the
> notation "lower 1/64" which is only true for flashes which either
> overflows in (3) or fill all entries (eg. with 3bits that would be
> the
> 32Mbit version).
> 

Looks like you noticed that we need new calculation method that would
be based on n_sectors :). Rule (1) is NOT true for some flashes
supporting BP0-2 and that's why I said that smallest protected portion
is fixed as '1/64' for these flashes.

See this one.

W25Q20EW	256KB	1/4 ... = 64KB		BP2
W25Q128JV	16MB	1/64 ... = 256KB	BP2 <--
S25FL132K	4MB	1/64 ... = 64KB		BP2 <--
S25FL164K	8MB	
1/64 ... = 128KB	BP2 <--
W25Q256JV	32MB	1/512 ... =
64KB	BP3
S25FL128L	16MB	1/256 ... = 64KB	BP3
S25FL256L	32MB	1/512 ... = 64KB	BP3

In current BP implementation, block protection is just working for some
flashes that has smallest protected portion as '1/64'.

We need new fomula based on n_sectors for BP3 at least.

> So for the 3 bit case the following flashes are border cases:
>   - 16mbit (less settings than slots)
>   - 32mbit (number of settings and free slots match)
>   - 64mbit (more settings than slots, first setting is discarded)
> 
> That being said, I suspect all the 16mbit flashes (and below) which
> have
> the _LOCK bit set are broken, because the entries has to be shifted. 
> I'll
> look into that later. This is the same "issue" you have with the 4
> bits.
> So if this is fixed, you should not need another formula for the 4
> bit
> case.
> 
> > We need new calculation method for 4bit block protection and for
> > making
> > it more generic, I choose n_sectors.
> > 
> > On all the flashes I checked, n_sectors is proper value for getting
> > block protected portion.
> > 
> > 		density	portion	n_sectors
> > W25M512JV	64MB	1/512	512
> > N25Q128A	16MB	1/256	256
> > N25Q512A	64MB	1/1024	1024
> > MT25QL02GCBB	256MB	1/4096	4096
> 
> The rules above apply to these flashes, too. Could you double check 
> that?
> 
> -michael
> 
> > 
> > > > +		val = val << SR_BP_SHIFT;
> > > > +
> > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
> > > > +			val = (val & ~BIT(5)) | BIT(6);
> > > > +	} else {
> > > > +		val = mask - (pow << SR_BP_SHIFT);
> > > > +	}
> > > > +
> > > >  	if (val & ~mask)
> > > >  		return -EINVAL;
> > > >  	/* Don't "lock" with no region! */
> > > > @@ -1983,6 +2057,13 @@ static int stm_unlock(struct spi_nor
> > > > *nor,
> > > > loff_t ofs, uint64_t len)
> > > > 
> > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> > > >  		tb_mask = SR_TB_BIT6;
> > > > +
> > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
> > > > +			mask = mask | SR_BP3_BIT6;
> > > > +		else
> > > > +			mask = mask | SR_BP3_BIT5;
> > > > +	}
> > > >  	/*
> > > >  	 * Need largest pow such that:
> > > >  	 *
> > > > @@ -1995,13 +2076,20 @@ static int stm_unlock(struct spi_nor
> > > > *nor,
> > > > loff_t ofs, uint64_t len)
> > > >  	pow = ilog2(mtd->size) - order_base_2(lock_len);
> > > >  	if (lock_len == 0) {
> > > >  		val = 0; /* fully unlocked */
> > > > +	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
> > > > +		val = val << SR_BP_SHIFT;
> > > > +
> > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
> > > > +			val = (val & ~BIT(5)) | BIT(6);
> > > >  	} else {
> > > >  		val = mask - (pow << SR_BP_SHIFT);
> > > > -		/* Some power-of-two sizes are not supported */
> > > > -		if (val & ~mask)
> > > > -			return -EINVAL;
> > > >  	}
> > > > 
> > > > +	/* Some power-of-two sizes are not supported */
> > > > +	if (val & ~mask)
> > > > +		return -EINVAL;
> > > > +
> > > >  	status_new = (status_old & ~mask & ~tb_mask) | val;
> > > > 
> > > >  	/* Don't protect status register if we're fully
> > > > unlocked */
> > > > @@ -4736,6 +4824,7 @@ static void
> > > > spi_nor_info_init_params(struct
> > > > spi_nor *nor)
> > > >  	/* Set SPI NOR sizes. */
> > > >  	params->size = (u64)info->sector_size * info-
> > > > >n_sectors;
> > > >  	params->page_size = info->page_size;
> > > > +	params->n_sectors = info->n_sectors;
> > > > 
> > > >  	if (!(info->flags & SPI_NOR_NO_FR)) {
> > > >  		/* Default to Fast Read for DT and non-DT
> > > > platform
> > > > devices. */
> > > > @@ -5192,6 +5281,11 @@ int spi_nor_scan(struct spi_nor *nor,
> > > > const
> > > > char *name,
> > > >  		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
> > > >  	if (info->flags & USE_CLSR)
> > > >  		nor->flags |= SNOR_F_USE_CLSR;
> > > > +	if (info->flags & SPI_NOR_HAS_BP3) {
> > > > +		nor->flags |= SNOR_F_HAS_SR_BP3;
> > > > +		if (info->flags & SPI_NOR_BP3_SR_BIT6)
> > > > +			nor->flags |= SNOR_F_HAS_SR_BP3_BIT6;
> > > > +	}
> > > > 
> > > >  	if (info->flags & SPI_NOR_NO_ERASE)
> > > >  		mtd->flags |= MTD_NO_ERASE;
> > > > @@ -5199,6 +5293,7 @@ int spi_nor_scan(struct spi_nor *nor,
> > > > const
> > > > char *name,
> > > >  	mtd->dev.parent = dev;
> > > >  	nor->page_size = params->page_size;
> > > >  	mtd->writebufsize = nor->page_size;
> > > > +	nor->n_sectors = params->n_sectors;
> > > > 
> > > >  	if (of_property_read_bool(np, "broken-flash-reset"))
> > > >  		nor->flags |= SNOR_F_BROKEN_RESET;
> > > > diff --git a/include/linux/mtd/spi-nor.h
> > > > b/include/linux/mtd/spi-
> > > > nor.h
> > > > index 541c06d042e8..92d550501daf 100644
> > > > --- a/include/linux/mtd/spi-nor.h
> > > > +++ b/include/linux/mtd/spi-nor.h
> > > > @@ -129,7 +129,9 @@
> > > >  #define SR_BP1			BIT(3)	/* Block protect 1
> > > > */
> > > >  #define SR_BP2			BIT(4)	/* Block protect 2
> > > > */
> > > >  #define SR_TB_BIT5		BIT(5)	/* Top/Bottom protect
> > > > */
> > > > +#define SR_BP3_BIT5		BIT(5)	/* Block protect 3
> > > > */
> > > 
> > > maybe just name it SR_BP3? would also be more consistent with the
> > > proposal
> > > above.
> > > 
> > > >  #define SR_TB_BIT6		BIT(6)	/* Top/Bottom protect
> > > > */
> > > > +#define SR_BP3_BIT6		BIT(6)	/* Block protect 3
> > > > */
> > > >  #define SR_SRWD			BIT(7)	/* SR write
> > > > protect
> > > > */
> > > >  /* Spansion/Cypress specific status bits */
> > > >  #define SR_E_ERR		BIT(5)
> > > > @@ -248,6 +250,8 @@ enum spi_nor_option_flags {
> > > >  	SNOR_F_HAS_16BIT_SR	= BIT(9),
> > > >  	SNOR_F_NO_READ_CR	= BIT(10),
> > > >  	SNOR_F_HAS_SR_TB_BIT6	= BIT(11),
> > > > +	SNOR_F_HAS_SR_BP3	= BIT(12),
> > > > +	SNOR_F_HAS_SR_BP3_BIT6	= BIT(13),
> > > > 
> > > >  };
> > > > 
> > > > @@ -519,6 +523,7 @@ struct spi_nor_locking_ops {
> > > >   *
> > > >   * @size:		the flash memory density in bytes.
> > > >   * @page_size:		the page size of the SPI NOR flash
> > > > memory.
> > > > + * @n_sectors:		number of sectors
> > > >   * @hwcaps:		describes the read and page program
> > > > hardware
> > > >   *			capabilities.
> > > >   * @reads:		read capabilities ordered by priority:
> > > > the
> > > > higher index
> > > > @@ -541,6 +546,7 @@ struct spi_nor_locking_ops {
> > > >  struct spi_nor_flash_parameter {
> > > >  	u64				size;
> > > >  	u32				page_size;
> > > > +	u16				n_sectors;
> > > > 
> > > >  	struct spi_nor_hwcaps		hwcaps;
> > > >  	struct spi_nor_read_command	reads[SNOR_CMD_READ_MAX
> > > > ];
> > > > @@ -573,6 +579,7 @@ struct flash_info;
> > > >   * @bouncebuf_size:	size of the bounce buffer
> > > >   * @info:		spi-nor part JDEC MFR id and other info
> > > >   * @page_size:		the page size of the SPI NOR
> > > > + * @n_sector:		number of sectors
> > > >   * @addr_width:		number of address bytes
> > > >   * @erase_opcode:	the opcode for erasing a sector
> > > >   * @read_opcode:	the read opcode
> > > > @@ -599,6 +606,7 @@ struct spi_nor {
> > > >  	size_t			bouncebuf_size;
> > > >  	const struct flash_info	*info;
> > > >  	u32			page_size;
> > > > +	u16			n_sectors;
> > > >  	u8			addr_width;
> > > >  	u8			erase_opcode;
> > > >  	u8			read_opcode;
> > > > --
> > > > 2.17.1
> > > > 
> > > > 
> > > > ______________________________________________________
> > > > Linux MTD discussion mailing list
> > > > 
> > 
> > 
https://protect2.fireeye.com/url?k=06b6dd5d-5b7d5a63-06b75612-0cc47a31309a-83164929001f7741&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
> > > > 
> > > 
> > > 
> 
> 


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Am 2020-01-23 09:53, schrieb Jungseung Lee:
> Hi, Michael
> 
> 2020-01-23 (Thu), 09:10 +0100, Michael Walle:
>> Hi Jungseung,
>> 
>> Am 2020-01-23 07:22, schrieb Jungseung Lee:
>> > Hi, Michael
>> >
>> > 2020-01-22 (Wed), 20:36 +0100, Michael Walle:
>> > > Hi,
>> > >
>> > > > Currently, we are supporting block protection only for
>> > > > flash chips with 3 block protection bits in the SR register.
>> > > > This patch enables block protection support for some flash with
>> > > > 4 block protection bits(bp0-3).
>> > > >
>> > > > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
>> > > > ---
>> > > > v3 :
>> > > >   Fix wrong ofs calculation on v2 patch
>> > > > v2 :
>> > > >   Add sample table portion about 4bit block protection on the
>> > > > comment
>> > > >   Trivial coding style change
>> > > >
>> > > >  drivers/mtd/spi-nor/spi-nor.c | 127
>> > > > +++++++++++++++++++++++++++++-
>> > > > ----
>> > > >  include/linux/mtd/spi-nor.h   |   8 +++
>> > > >  2 files changed, 119 insertions(+), 16 deletions(-)
>> > > >
>> > > > diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-
>> > > > nor/spi-nor.c
>> > > > index e3da6a8654a8..7e8af6c4fdfa 100644
>> > > > --- a/drivers/mtd/spi-nor/spi-nor.c
>> > > > +++ b/drivers/mtd/spi-nor/spi-nor.c
>> > > > @@ -238,6 +238,14 @@ struct flash_info {
>> > > >  					 * status register.
>> > > > Must be
>> > > > used with
>> > > >  					 * SPI_NOR_HAS_TB.
>> > > >  					 */
>> > > > +#define SPI_NOR_HAS_BP3		BIT(17)	/*
>> > > > +					 * Flash SR has 4 bit
>> > > > fields
>> > > > (BP0-3)
>> > > > +					 * for block
>> > > > protection.
>> > > > +					 */
>> > > > +#define SPI_NOR_BP3_SR_BIT6	BIT(18)	/*
>> > > > +					 * BP3 is bit 6 of
>> > > > status
>> > > > register.
>> > > > +					 * Must be used with
>> > > > SPI_NOR_HAS_BP3.
>> > > > +					 */
>> > > >
>> > > >  	/* Part specific fixup hooks. */
>> > > >  	const struct spi_nor_fixups *fixups;
>> > > > @@ -1767,23 +1775,47 @@ static void stm_get_locked_range(struct
>> > > > spi_nor *nor, u8 sr, loff_t *ofs,
>> > > >  	struct mtd_info *mtd = &nor->mtd;
>> > > >  	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
>> > > >  	u8 tb_mask = SR_TB_BIT5;
>> > > > -	int pow;
>> > > > +	u8 bp;
>> > > > +	int pow = 0;
>> > > >
>> > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>> > > >  		tb_mask = SR_TB_BIT6;
>> > > >
>> > > > -	if (!(sr & mask)) {
>> > > > -		/* No protection */
>> > > > -		*ofs = 0;
>> > > > -		*len = 0;
>> > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > +		u8 tmp;
>> > > > +
>> > > > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
>> > > > +			tmp = sr & (mask | SR_BP3_BIT6);
>> > > > +		else
>> > > > +			tmp = sr & (mask | SR_BP3_BIT5);
>> > > > +
>> > > > +		if (tmp & SR_BP3_BIT6)
>> > > > +			tmp = (tmp & ~BIT(6)) | BIT(5);
>> > > > +
>> > > > +		bp = tmp >> SR_BP_SHIFT;
>> > > > +		if (!bp) {
>> > > > +			*ofs = 0;
>> > > > +			*len = 0;
>> > > > +			return;
>> > > > +		}
>> > > > +		if (bp <= ilog2(nor->n_sectors))
>> > > > +			pow = ilog2(nor->n_sectors) + 1 - bp;
>> > > >  	} else {
>> > > > -		pow = ((sr & mask) ^ mask) >> SR_BP_SHIFT;
>> > > > -		*len = mtd->size >> pow;
>> > > > -		if (nor->flags & SNOR_F_HAS_SR_TB && sr &
>> > > > tb_mask)
>> > > > +		bp = (sr & mask) >> SR_BP_SHIFT;
>> > > > +		if (!bp) {
>> > > >  			*ofs = 0;
>> > > > -		else
>> > > > -			*ofs = mtd->size - *len;
>> > > > +			*len = 0;
>> > > > +			return;
>> > > > +		}
>> > > > +		pow = bp ^ (mask >> SR_BP_SHIFT);
>> > > >  	}
>> > > > +
>> > > > +	*len = mtd->size >> pow;
>> > > > +
>> > > > +	if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
>> > > > +		*ofs = 0;
>> > > > +	else
>> > > > +		*ofs = mtd->size - *len;
>> > > >  }
>> > > >
>> > > >  /*
>> > > > @@ -1823,7 +1855,7 @@ static int stm_is_unlocked_sr(struct
>> > > > spi_nor
>> > > > *nor, loff_t ofs, uint64_t len,
>> > > >
>> > > >  /*
>> > > >   * Lock a region of the flash. Compatible with ST Micro and
>> > > > similar flash.
>> > > > - * Supports the block protection bits BP{0,1,2} in the status
>> > > > register
>> > > > + * Supports the block protection bits BP{0,1,2,3} in the
>> > > > status
>> > > > register
>> > > >   * (SR). Does not support these features found in newer SR
>> > > > bitfields:
>> > > >   *   - SEC: sector/block protect - only handle SEC=0 (block
>> > > > protect)
>> > > >   *   - CMP: complement protect - only support CMP=0 (range is
>> > > > not
>> > > > complemented)
>> > > > @@ -1831,7 +1863,7 @@ static int stm_is_unlocked_sr(struct
>> > > > spi_nor
>> > > > *nor, loff_t ofs, uint64_t len,
>> > > >   * Support for the following is provided conditionally for
>> > > > some
>> > > > flash:
>> > > >   *   - TB: top/bottom protect
>> > > >   *
>> > > > - * Sample table portion for 8MB flash (Winbond w25q64fw):
>> > > > + * Sample table portion for 8MB flash (Winbond w25q64fw / BP0-
>> > > > 2):
>> > > >   *
>> > > >   *   SEC  |  TB   |  BP2  |  BP1  |  BP0  |  Prot Length  |
>> > > > Protected Portion
>> > > >   *  --------------------------------------------------------
>> > > > ----
>> > > > --------------
>> > > > @@ -1851,6 +1883,32 @@ static int stm_is_unlocked_sr(struct
>> > > > spi_nor
>> > > > *nor, loff_t ofs, uint64_t len,
>> > > >   *    0   |   1   |   1   |   0   |   1   |  2 MB         |
>> > > > Lower
>> > > > 1/4
>> > > >   *    0   |   1   |   1   |   1   |   0   |  4 MB         |
>> > > > Lower
>> > > > 1/2
>> > > >   *
>> > > > + * Sample table portion for 64MB flash (Micron n25q512ax3 /
>> > > > BP0-
>> > > > 3):
>> > > > + *
>> > > > + *   TB   |  BP3  |  BP2  |  BP1  |  BP0  |  Prot Length  |
>> > > > Protected Portion
>> > > > + *  --------------------------------------------------------
>> > > > ----
>> > > > --------------
>> > > > + *    0   |   0   |   0   |   0   |   0   |  NONE         |
>> > > > NONE
>> > > > + *    0   |   0   |   0   |   0   |   1   |   64 KB       |
>> > > > Upper
>> > > > 1/1024
>> > > > + *    0   |   0   |   0   |   1   |   0   |  128 KB       |
>> > > > Upper
>> > > > 1/512
>> > > > + *    0   |   0   |   0   |   1   |   1   |  256 KB       |
>> > > > Upper
>> > > > 1/256
>> > > > + *   ...
>> > > > + *    0   |   1   |   0   |   0   |   1   |  16 MB        |
>> > > > Upper
>> > > > 1/4
>> > > > + *    0   |   1   |   0   |   1   |   0   |  32 MB        |
>> > > > Upper
>> > > > 1/2
>> > > > + *    0   |   1   |   0   |   1   |   1   |  64 MB        |
>> > > > ALL
>> > > > + *    0   |   1   |   1   |   0   |   0   |  64 MB        |
>> > > > ALL
>> > > > + *   ...
>> > > > + *  ------|-------|-------|-------|-------|---------------|---
>> > > > ----
>> > > > ------------
>> > > > + *    1   |   0   |   0   |   0   |   0   |   NONE        |
>> > > > NONE
>> > > > + *    1   |   0   |   0   |   0   |   1   |   64 KB       |
>> > > > Lower
>> > > > 1/1024
>> > > > + *    1   |   0   |   0   |   1   |   0   |  128 KB       |
>> > > > Lower
>> > > > 1/512
>> > > > + *    1   |   0   |   0   |   1   |   1   |  256 KB       |
>> > > > Lower
>> > > > 1/256
>> > > > + *   ...
>> > > > + *    1   |   1   |   0   |   0   |   1   |  16 MB        |
>> > > > Lower
>> > > > 1/4
>> > > > + *    1   |   1   |   0   |   1   |   0   |  32 MB        |
>> > > > Lower
>> > > > 1/2
>> > > > + *    1   |   1   |   0   |   1   |   1   |  64 MB        |
>> > > > ALL
>> > > > + *    1   |   1   |   1   |   0   |   0   |  64 MB        |
>> > > > ALL
>> > > > + *   ...
>> > > > + *
>> > > >   * Returns negative on errors, 0 on success.
>> > > >   */
>> > > >  static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t
>> > > > len)
>> > > > @@ -1898,6 +1956,12 @@ static int stm_lock(struct spi_nor *nor,
>> > > > loff_t ofs, uint64_t len)
>> > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>> > > >  		tb_mask = SR_TB_BIT6;
>> > > >
>> > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
>> > > > +			mask = mask | SR_BP3_BIT6;
>> > > > +		else
>> > > > +			mask = mask | SR_BP3_BIT5;
>> > > > +	}
>> > > >  	/*
>> > > >  	 * Need smallest pow such that:
>> > > >  	 *
>> > > > @@ -1908,7 +1972,17 @@ static int stm_lock(struct spi_nor *nor,
>> > > > loff_t ofs, uint64_t len)
>> > > >  	 *   pow = ceil(log2(size / len)) = log2(size) -
>> > > > floor(log2(len))
>> > > >  	 */
>> > > >  	pow = ilog2(mtd->size) - ilog2(lock_len);
>> > > > -	val = mask - (pow << SR_BP_SHIFT);
>> > > > +
>> > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
>> > >
>> > > Why do you use a new calculation here? As far as I can see, the
>> > > method is
>> > > the same except that is has one bit more. That also raises the
>> > > question why
>> > > n_sectors is now needed?
>> > >
>> > > Can't we just initialize the mask with
>> > >
>> > > mask = SR_BP2 | SR_BP1 | SR_BP0;
>> > > if (nor->flags & SNOR_F_HAS_SR_BP3)
>> > >     mask |= SR_BP3_BIT5;
>> > >
>> > > do the calculation and checks and then move the SR_BP3_BIT5 to
>> > > SR_BP3_BIT6
>> > > if SNOR_F_HAS_SR_BP3_BIT6 is set.
>> > >
>> >
>> > For most of flashes that supporting BP0-2, the smallest protected
>> > portion is fixed as 1/64
>> > and it can be properly handled by existing
>> > calculation. (Actually it's not fully generic, see flashes like
>> > w25q40bw or m25p80. Of course, it doesn't have SPI_NOR_HAS_LOCK
>> > flag
>> > even though it has BP0-2 bit in SR)
>> 
>> No. The rules are always the same wether there are three or four BP
>> bits (the example in stm_lock() has not enough information on this):
>> 
>> (1) the first setting (besides 0) protects one sector. The second
>>      protects 2, the third 4 and so on. eg 2^N
>> (2) the last setting is _always_ protect all, just like the '0'
>> setting
>>      is always protect none.
>> (3) if there is an overflow because there are no more free slots for
>>      further settings (for 3 bits with flashes > 32MBit, for 4
>>      bits if should be flashes > 16GBit), the first entry will be
>>      discarded (eg the very first is the "just one sector" entry).
>> 
>> This is true for all flashes which uses this kind of setting, have a
>> look at the m25p80 or w25q40bw, these are no exception. It is just
>> the
>> notation "lower 1/64" which is only true for flashes which either
>> overflows in (3) or fill all entries (eg. with 3bits that would be
>> the
>> 32Mbit version).
>> 
> 
> Looks like you noticed that we need new calculation method that would
> be based on n_sectors :).

No it will work without that (if I'm not mistaken). Give me some time
and I'll post a patch.

> Rule (1) is NOT true for some flashes
> supporting BP0-2 and that's why I said that smallest protected portion
> is fixed as '1/64' for these flashes.

No, you have to apply rule (3). (1) is only the starting point. It is 
kind
of a sliding window.

> See this one.
> 
> W25Q20EW	256KB	1/4 ... = 64KB		BP2
> W25Q128JV	16MB	1/64 ... = 256KB	BP2 <--
> S25FL132K	4MB	1/64 ... = 64KB		BP2 <--
> S25FL164K	8MB
> 1/64 ... = 128KB	BP2 <--

All these flashes need (3) to be applied, thus (1) doesn't apply
anymore.

Let me give you an example for the 64MBit case, the settings would be:

0 sectors (corresponds to protect none)
1 sector
2 sectors
4 sectors
8 sectors
16 sectors
32 sectors
64 sectors
128 sectors (corresponds to protect all)

Unfortunately, we have only 8 slots (because 3 BP bits), therefore we 
have
to discard some setting. According to rule (2) 0 is always "protect 
none"
and 7 is always "protect all". Thus we have 6 settings left. According 
to
rule (3) we discard the first ones. In this case, this is the "1 sector"
setting. Thus we end up with the following possible settings:

0 sectors (corresponds to protect none)
2 sectors
4 sectors
8 sectors
16 sectors
32 sectors
64 sectors
128 sectors (corresponds to protect all)

If you have a 128Mbit flash, the next setting that would be discarded is
"2 sectors". Thus it would start with:

0 sectors (corresponds to protect none)
4 sectors
[..]
256 sectors (corresponds to protect all)


Another example W25Q20EW, following possible settings:

0 sectors (corresponds to protect none)
1 sector
2 sectors
4 sectors (corresponds to protect all)

We now have less settings then our 8 possible slots. So this is where
rule (1) applies, because according to that the "1 sector" setting is
the first possible setting besides 0.

And this also applies to the 4 bit protection bits.



> W25Q256JV	32MB	1/512 ... =
> 64KB	BP3
> S25FL128L	16MB	1/256 ... = 64KB	BP3
> S25FL256L	32MB	1/512 ... = 64KB	BP3
> 
> In current BP implementation, block protection is just working for some
> flashes that has smallest protected portion as '1/64'.

No its currently working for all except flashes smaller than 32Mbit.
Applied to the 4 bits, this would mean "it works for all except flashes
smaller than 8Gbit" which are practially all. As I said, this is a bug
and once this bug is fixed, there should be no difference between 3
and 4 bits.

-michael

> 
> We need new fomula based on n_sectors for BP3 at least.

No they are the same, but yes there is a bug in the current
implementation.

-michael

> 
>> So for the 3 bit case the following flashes are border cases:
>>   - 16mbit (less settings than slots)
>>   - 32mbit (number of settings and free slots match)
>>   - 64mbit (more settings than slots, first setting is discarded)
>> 
>> That being said, I suspect all the 16mbit flashes (and below) which
>> have
>> the _LOCK bit set are broken, because the entries has to be shifted.
>> I'll
>> look into that later. This is the same "issue" you have with the 4
>> bits.
>> So if this is fixed, you should not need another formula for the 4
>> bit
>> case.
>> 
>> > We need new calculation method for 4bit block protection and for
>> > making
>> > it more generic, I choose n_sectors.
>> >
>> > On all the flashes I checked, n_sectors is proper value for getting
>> > block protected portion.
>> >
>> > 		density	portion	n_sectors
>> > W25M512JV	64MB	1/512	512
>> > N25Q128A	16MB	1/256	256
>> > N25Q512A	64MB	1/1024	1024
>> > MT25QL02GCBB	256MB	1/4096	4096
>> 
>> The rules above apply to these flashes, too. Could you double check
>> that?
>> 
>> -michael
>> 
>> >
>> > > > +		val = val << SR_BP_SHIFT;
>> > > > +
>> > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
>> > > > +			val = (val & ~BIT(5)) | BIT(6);
>> > > > +	} else {
>> > > > +		val = mask - (pow << SR_BP_SHIFT);
>> > > > +	}
>> > > > +
>> > > >  	if (val & ~mask)
>> > > >  		return -EINVAL;
>> > > >  	/* Don't "lock" with no region! */
>> > > > @@ -1983,6 +2057,13 @@ static int stm_unlock(struct spi_nor
>> > > > *nor,
>> > > > loff_t ofs, uint64_t len)
>> > > >
>> > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>> > > >  		tb_mask = SR_TB_BIT6;
>> > > > +
>> > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
>> > > > +			mask = mask | SR_BP3_BIT6;
>> > > > +		else
>> > > > +			mask = mask | SR_BP3_BIT5;
>> > > > +	}
>> > > >  	/*
>> > > >  	 * Need largest pow such that:
>> > > >  	 *
>> > > > @@ -1995,13 +2076,20 @@ static int stm_unlock(struct spi_nor
>> > > > *nor,
>> > > > loff_t ofs, uint64_t len)
>> > > >  	pow = ilog2(mtd->size) - order_base_2(lock_len);
>> > > >  	if (lock_len == 0) {
>> > > >  		val = 0; /* fully unlocked */
>> > > > +	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
>> > > > +		val = val << SR_BP_SHIFT;
>> > > > +
>> > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
>> > > > +			val = (val & ~BIT(5)) | BIT(6);
>> > > >  	} else {
>> > > >  		val = mask - (pow << SR_BP_SHIFT);
>> > > > -		/* Some power-of-two sizes are not supported */
>> > > > -		if (val & ~mask)
>> > > > -			return -EINVAL;
>> > > >  	}
>> > > >
>> > > > +	/* Some power-of-two sizes are not supported */
>> > > > +	if (val & ~mask)
>> > > > +		return -EINVAL;
>> > > > +
>> > > >  	status_new = (status_old & ~mask & ~tb_mask) | val;
>> > > >
>> > > >  	/* Don't protect status register if we're fully
>> > > > unlocked */
>> > > > @@ -4736,6 +4824,7 @@ static void
>> > > > spi_nor_info_init_params(struct
>> > > > spi_nor *nor)
>> > > >  	/* Set SPI NOR sizes. */
>> > > >  	params->size = (u64)info->sector_size * info-
>> > > > >n_sectors;
>> > > >  	params->page_size = info->page_size;
>> > > > +	params->n_sectors = info->n_sectors;
>> > > >
>> > > >  	if (!(info->flags & SPI_NOR_NO_FR)) {
>> > > >  		/* Default to Fast Read for DT and non-DT
>> > > > platform
>> > > > devices. */
>> > > > @@ -5192,6 +5281,11 @@ int spi_nor_scan(struct spi_nor *nor,
>> > > > const
>> > > > char *name,
>> > > >  		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
>> > > >  	if (info->flags & USE_CLSR)
>> > > >  		nor->flags |= SNOR_F_USE_CLSR;
>> > > > +	if (info->flags & SPI_NOR_HAS_BP3) {
>> > > > +		nor->flags |= SNOR_F_HAS_SR_BP3;
>> > > > +		if (info->flags & SPI_NOR_BP3_SR_BIT6)
>> > > > +			nor->flags |= SNOR_F_HAS_SR_BP3_BIT6;
>> > > > +	}
>> > > >
>> > > >  	if (info->flags & SPI_NOR_NO_ERASE)
>> > > >  		mtd->flags |= MTD_NO_ERASE;
>> > > > @@ -5199,6 +5293,7 @@ int spi_nor_scan(struct spi_nor *nor,
>> > > > const
>> > > > char *name,
>> > > >  	mtd->dev.parent = dev;
>> > > >  	nor->page_size = params->page_size;
>> > > >  	mtd->writebufsize = nor->page_size;
>> > > > +	nor->n_sectors = params->n_sectors;
>> > > >
>> > > >  	if (of_property_read_bool(np, "broken-flash-reset"))
>> > > >  		nor->flags |= SNOR_F_BROKEN_RESET;
>> > > > diff --git a/include/linux/mtd/spi-nor.h
>> > > > b/include/linux/mtd/spi-
>> > > > nor.h
>> > > > index 541c06d042e8..92d550501daf 100644
>> > > > --- a/include/linux/mtd/spi-nor.h
>> > > > +++ b/include/linux/mtd/spi-nor.h
>> > > > @@ -129,7 +129,9 @@
>> > > >  #define SR_BP1			BIT(3)	/* Block protect 1
>> > > > */
>> > > >  #define SR_BP2			BIT(4)	/* Block protect 2
>> > > > */
>> > > >  #define SR_TB_BIT5		BIT(5)	/* Top/Bottom protect
>> > > > */
>> > > > +#define SR_BP3_BIT5		BIT(5)	/* Block protect 3
>> > > > */
>> > >
>> > > maybe just name it SR_BP3? would also be more consistent with the
>> > > proposal
>> > > above.
>> > >
>> > > >  #define SR_TB_BIT6		BIT(6)	/* Top/Bottom protect
>> > > > */
>> > > > +#define SR_BP3_BIT6		BIT(6)	/* Block protect 3
>> > > > */
>> > > >  #define SR_SRWD			BIT(7)	/* SR write
>> > > > protect
>> > > > */
>> > > >  /* Spansion/Cypress specific status bits */
>> > > >  #define SR_E_ERR		BIT(5)
>> > > > @@ -248,6 +250,8 @@ enum spi_nor_option_flags {
>> > > >  	SNOR_F_HAS_16BIT_SR	= BIT(9),
>> > > >  	SNOR_F_NO_READ_CR	= BIT(10),
>> > > >  	SNOR_F_HAS_SR_TB_BIT6	= BIT(11),
>> > > > +	SNOR_F_HAS_SR_BP3	= BIT(12),
>> > > > +	SNOR_F_HAS_SR_BP3_BIT6	= BIT(13),
>> > > >
>> > > >  };
>> > > >
>> > > > @@ -519,6 +523,7 @@ struct spi_nor_locking_ops {
>> > > >   *
>> > > >   * @size:		the flash memory density in bytes.
>> > > >   * @page_size:		the page size of the SPI NOR flash
>> > > > memory.
>> > > > + * @n_sectors:		number of sectors
>> > > >   * @hwcaps:		describes the read and page program
>> > > > hardware
>> > > >   *			capabilities.
>> > > >   * @reads:		read capabilities ordered by priority:
>> > > > the
>> > > > higher index
>> > > > @@ -541,6 +546,7 @@ struct spi_nor_locking_ops {
>> > > >  struct spi_nor_flash_parameter {
>> > > >  	u64				size;
>> > > >  	u32				page_size;
>> > > > +	u16				n_sectors;
>> > > >
>> > > >  	struct spi_nor_hwcaps		hwcaps;
>> > > >  	struct spi_nor_read_command	reads[SNOR_CMD_READ_MAX
>> > > > ];
>> > > > @@ -573,6 +579,7 @@ struct flash_info;
>> > > >   * @bouncebuf_size:	size of the bounce buffer
>> > > >   * @info:		spi-nor part JDEC MFR id and other info
>> > > >   * @page_size:		the page size of the SPI NOR
>> > > > + * @n_sector:		number of sectors
>> > > >   * @addr_width:		number of address bytes
>> > > >   * @erase_opcode:	the opcode for erasing a sector
>> > > >   * @read_opcode:	the read opcode
>> > > > @@ -599,6 +606,7 @@ struct spi_nor {
>> > > >  	size_t			bouncebuf_size;
>> > > >  	const struct flash_info	*info;
>> > > >  	u32			page_size;
>> > > > +	u16			n_sectors;
>> > > >  	u8			addr_width;
>> > > >  	u8			erase_opcode;
>> > > >  	u8			read_opcode;
>> > > > --
>> > > > 2.17.1
>> > > >
>> > > >
>> > > > ______________________________________________________
>> > > > Linux MTD discussion mailing list
>> > > >
>> >
>> >
> https://protect2.fireeye.com/url?k=06b6dd5d-5b7d5a63-06b75612-0cc47a31309a-83164929001f7741&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
>> > > >
>> > >
>> > >
>> 
>> 

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Hi, Michael

2020-01-23 (Thu), 10:31 +0100, Michael Walle:
> Am 2020-01-23 09:53, schrieb Jungseung Lee:
> > Hi, Michael
> > 
> > 2020-01-23 (Thu), 09:10 +0100, Michael Walle:
> > > Hi Jungseung,
> > > 
> > > Am 2020-01-23 07:22, schrieb Jungseung Lee:
> > > > Hi, Michael
> > > > 
> > > > 2020-01-22 (Wed), 20:36 +0100, Michael Walle:
> > > > > Hi,
> > > > > 
> > > > > > Currently, we are supporting block protection only for
> > > > > > flash chips with 3 block protection bits in the SR
> > > > > > register.
> > > > > > This patch enables block protection support for some flash
> > > > > > with
> > > > > > 4 block protection bits(bp0-3).
> > > > > > 
> > > > > > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> > > > > > ---
> > > > > > v3 :
> > > > > >   Fix wrong ofs calculation on v2 patch
> > > > > > v2 :
> > > > > >   Add sample table portion about 4bit block protection on
> > > > > > the
> > > > > > comment
> > > > > >   Trivial coding style change
> > > > > > 
> > > > > >  drivers/mtd/spi-nor/spi-nor.c | 127
> > > > > > +++++++++++++++++++++++++++++-
> > > > > > ----
> > > > > >  include/linux/mtd/spi-nor.h   |   8 +++
> > > > > >  2 files changed, 119 insertions(+), 16 deletions(-)
> > > > > > 
> > > > > > diff --git a/drivers/mtd/spi-nor/spi-nor.c
> > > > > > b/drivers/mtd/spi-
> > > > > > nor/spi-nor.c
> > > > > > index e3da6a8654a8..7e8af6c4fdfa 100644
> > > > > > --- a/drivers/mtd/spi-nor/spi-nor.c
> > > > > > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > > > > > @@ -238,6 +238,14 @@ struct flash_info {
> > > > > >  					 * status register.
> > > > > > Must be
> > > > > > used with
> > > > > >  					 * SPI_NOR_HAS_TB.
> > > > > >  					 */
> > > > > > +#define SPI_NOR_HAS_BP3		BIT(17)	/*
> > > > > > +					 * Flash SR has 4 bit
> > > > > > fields
> > > > > > (BP0-3)
> > > > > > +					 * for block
> > > > > > protection.
> > > > > > +					 */
> > > > > > +#define SPI_NOR_BP3_SR_BIT6	BIT(18)	/*
> > > > > > +					 * BP3 is bit 6 of
> > > > > > status
> > > > > > register.
> > > > > > +					 * Must be used with
> > > > > > SPI_NOR_HAS_BP3.
> > > > > > +					 */
> > > > > > 
> > > > > >  	/* Part specific fixup hooks. */
> > > > > >  	const struct spi_nor_fixups *fixups;
> > > > > > @@ -1767,23 +1775,47 @@ static void
> > > > > > stm_get_locked_range(struct
> > > > > > spi_nor *nor, u8 sr, loff_t *ofs,
> > > > > >  	struct mtd_info *mtd = &nor->mtd;
> > > > > >  	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
> > > > > >  	u8 tb_mask = SR_TB_BIT5;
> > > > > > -	int pow;
> > > > > > +	u8 bp;
> > > > > > +	int pow = 0;
> > > > > > 
> > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> > > > > >  		tb_mask = SR_TB_BIT6;
> > > > > > 
> > > > > > -	if (!(sr & mask)) {
> > > > > > -		/* No protection */
> > > > > > -		*ofs = 0;
> > > > > > -		*len = 0;
> > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > +		u8 tmp;
> > > > > > +
> > > > > > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
> > > > > > +			tmp = sr & (mask | SR_BP3_BIT6);
> > > > > > +		else
> > > > > > +			tmp = sr & (mask | SR_BP3_BIT5);
> > > > > > +
> > > > > > +		if (tmp & SR_BP3_BIT6)
> > > > > > +			tmp = (tmp & ~BIT(6)) | BIT(5);
> > > > > > +
> > > > > > +		bp = tmp >> SR_BP_SHIFT;
> > > > > > +		if (!bp) {
> > > > > > +			*ofs = 0;
> > > > > > +			*len = 0;
> > > > > > +			return;
> > > > > > +		}
> > > > > > +		if (bp <= ilog2(nor->n_sectors))
> > > > > > +			pow = ilog2(nor->n_sectors) + 1 - bp;
> > > > > >  	} else {
> > > > > > -		pow = ((sr & mask) ^ mask) >> SR_BP_SHIFT;
> > > > > > -		*len = mtd->size >> pow;
> > > > > > -		if (nor->flags & SNOR_F_HAS_SR_TB && sr &
> > > > > > tb_mask)
> > > > > > +		bp = (sr & mask) >> SR_BP_SHIFT;
> > > > > > +		if (!bp) {
> > > > > >  			*ofs = 0;
> > > > > > -		else
> > > > > > -			*ofs = mtd->size - *len;
> > > > > > +			*len = 0;
> > > > > > +			return;
> > > > > > +		}
> > > > > > +		pow = bp ^ (mask >> SR_BP_SHIFT);
> > > > > >  	}
> > > > > > +
> > > > > > +	*len = mtd->size >> pow;
> > > > > > +
> > > > > > +	if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
> > > > > > +		*ofs = 0;
> > > > > > +	else
> > > > > > +		*ofs = mtd->size - *len;
> > > > > >  }
> > > > > > 
> > > > > >  /*
> > > > > > @@ -1823,7 +1855,7 @@ static int stm_is_unlocked_sr(struct
> > > > > > spi_nor
> > > > > > *nor, loff_t ofs, uint64_t len,
> > > > > > 
> > > > > >  /*
> > > > > >   * Lock a region of the flash. Compatible with ST Micro
> > > > > > and
> > > > > > similar flash.
> > > > > > - * Supports the block protection bits BP{0,1,2} in the
> > > > > > status
> > > > > > register
> > > > > > + * Supports the block protection bits BP{0,1,2,3} in the
> > > > > > status
> > > > > > register
> > > > > >   * (SR). Does not support these features found in newer SR
> > > > > > bitfields:
> > > > > >   *   - SEC: sector/block protect - only handle SEC=0
> > > > > > (block
> > > > > > protect)
> > > > > >   *   - CMP: complement protect - only support CMP=0 (range
> > > > > > is
> > > > > > not
> > > > > > complemented)
> > > > > > @@ -1831,7 +1863,7 @@ static int stm_is_unlocked_sr(struct
> > > > > > spi_nor
> > > > > > *nor, loff_t ofs, uint64_t len,
> > > > > >   * Support for the following is provided conditionally for
> > > > > > some
> > > > > > flash:
> > > > > >   *   - TB: top/bottom protect
> > > > > >   *
> > > > > > - * Sample table portion for 8MB flash (Winbond w25q64fw):
> > > > > > + * Sample table portion for 8MB flash (Winbond w25q64fw /
> > > > > > BP0-
> > > > > > 2):
> > > > > >   *
> > > > > >   *   SEC  |  TB   |  BP2  |  BP1  |  BP0  |  Prot
> > > > > > Length  |
> > > > > > Protected Portion
> > > > > >   *  ----------------------------------------------------
> > > > > > ----
> > > > > > ----
> > > > > > --------------
> > > > > > @@ -1851,6 +1883,32 @@ static int stm_is_unlocked_sr(struct
> > > > > > spi_nor
> > > > > > *nor, loff_t ofs, uint64_t len,
> > > > > >   *    0   |   1   |   1   |   0   |   1   |  2
> > > > > > MB         |
> > > > > > Lower
> > > > > > 1/4
> > > > > >   *    0   |   1   |   1   |   1   |   0   |  4
> > > > > > MB         |
> > > > > > Lower
> > > > > > 1/2
> > > > > >   *
> > > > > > + * Sample table portion for 64MB flash (Micron n25q512ax3
> > > > > > /
> > > > > > BP0-
> > > > > > 3):
> > > > > > + *
> > > > > > + *   TB   |  BP3  |  BP2  |  BP1  |  BP0  |  Prot
> > > > > > Length  |
> > > > > > Protected Portion
> > > > > > + *  ----------------------------------------------------
> > > > > > ----
> > > > > > ----
> > > > > > --------------
> > > > > > +
> > > > > > *    0   |   0   |   0   |   0   |   0   |  NONE         |
> > > > > > NONE
> > > > > > + *    0   |   0   |   0   |   0   |   1   |   64
> > > > > > KB       |
> > > > > > Upper
> > > > > > 1/1024
> > > > > > + *    0   |   0   |   0   |   1   |   0   |  128
> > > > > > KB       |
> > > > > > Upper
> > > > > > 1/512
> > > > > > + *    0   |   0   |   0   |   1   |   1   |  256
> > > > > > KB       |
> > > > > > Upper
> > > > > > 1/256
> > > > > > + *   ...
> > > > > > + *    0   |   1   |   0   |   0   |   1   |  16
> > > > > > MB        |
> > > > > > Upper
> > > > > > 1/4
> > > > > > + *    0   |   1   |   0   |   1   |   0   |  32
> > > > > > MB        |
> > > > > > Upper
> > > > > > 1/2
> > > > > > + *    0   |   1   |   0   |   1   |   1   |  64
> > > > > > MB        |
> > > > > > ALL
> > > > > > + *    0   |   1   |   1   |   0   |   0   |  64
> > > > > > MB        |
> > > > > > ALL
> > > > > > + *   ...
> > > > > > + *  ------|-------|-------|-------|-------|---------------
> > > > > > |---
> > > > > > ----
> > > > > > ------------
> > > > > > +
> > > > > > *    1   |   0   |   0   |   0   |   0   |   NONE        |
> > > > > > NONE
> > > > > > + *    1   |   0   |   0   |   0   |   1   |   64
> > > > > > KB       |
> > > > > > Lower
> > > > > > 1/1024
> > > > > > + *    1   |   0   |   0   |   1   |   0   |  128
> > > > > > KB       |
> > > > > > Lower
> > > > > > 1/512
> > > > > > + *    1   |   0   |   0   |   1   |   1   |  256
> > > > > > KB       |
> > > > > > Lower
> > > > > > 1/256
> > > > > > + *   ...
> > > > > > + *    1   |   1   |   0   |   0   |   1   |  16
> > > > > > MB        |
> > > > > > Lower
> > > > > > 1/4
> > > > > > + *    1   |   1   |   0   |   1   |   0   |  32
> > > > > > MB        |
> > > > > > Lower
> > > > > > 1/2
> > > > > > + *    1   |   1   |   0   |   1   |   1   |  64
> > > > > > MB        |
> > > > > > ALL
> > > > > > + *    1   |   1   |   1   |   0   |   0   |  64
> > > > > > MB        |
> > > > > > ALL
> > > > > > + *   ...
> > > > > > + *
> > > > > >   * Returns negative on errors, 0 on success.
> > > > > >   */
> > > > > >  static int stm_lock(struct spi_nor *nor, loff_t ofs,
> > > > > > uint64_t
> > > > > > len)
> > > > > > @@ -1898,6 +1956,12 @@ static int stm_lock(struct spi_nor
> > > > > > *nor,
> > > > > > loff_t ofs, uint64_t len)
> > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> > > > > >  		tb_mask = SR_TB_BIT6;
> > > > > > 
> > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
> > > > > > +			mask = mask | SR_BP3_BIT6;
> > > > > > +		else
> > > > > > +			mask = mask | SR_BP3_BIT5;
> > > > > > +	}
> > > > > >  	/*
> > > > > >  	 * Need smallest pow such that:
> > > > > >  	 *
> > > > > > @@ -1908,7 +1972,17 @@ static int stm_lock(struct spi_nor
> > > > > > *nor,
> > > > > > loff_t ofs, uint64_t len)
> > > > > >  	 *   pow = ceil(log2(size / len)) = log2(size) -
> > > > > > floor(log2(len))
> > > > > >  	 */
> > > > > >  	pow = ilog2(mtd->size) - ilog2(lock_len);
> > > > > > -	val = mask - (pow << SR_BP_SHIFT);
> > > > > > +
> > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
> > > > > 
> > > > > Why do you use a new calculation here? As far as I can see,
> > > > > the
> > > > > method is
> > > > > the same except that is has one bit more. That also raises
> > > > > the
> > > > > question why
> > > > > n_sectors is now needed?
> > > > > 
> > > > > Can't we just initialize the mask with
> > > > > 
> > > > > mask = SR_BP2 | SR_BP1 | SR_BP0;
> > > > > if (nor->flags & SNOR_F_HAS_SR_BP3)
> > > > >     mask |= SR_BP3_BIT5;
> > > > > 
> > > > > do the calculation and checks and then move the SR_BP3_BIT5
> > > > > to
> > > > > SR_BP3_BIT6
> > > > > if SNOR_F_HAS_SR_BP3_BIT6 is set.
> > > > > 
> > > > 
> > > > For most of flashes that supporting BP0-2, the smallest
> > > > protected
> > > > portion is fixed as 1/64
> > > > and it can be properly handled by existing
> > > > calculation. (Actually it's not fully generic, see flashes like
> > > > w25q40bw or m25p80. Of course, it doesn't have SPI_NOR_HAS_LOCK
> > > > flag
> > > > even though it has BP0-2 bit in SR)
> > > 
> > > No. The rules are always the same wether there are three or four
> > > BP
> > > bits (the example in stm_lock() has not enough information on
> > > this):
> > > 
> > > (1) the first setting (besides 0) protects one sector. The second
> > >      protects 2, the third 4 and so on. eg 2^N
> > > (2) the last setting is _always_ protect all, just like the '0'
> > > setting
> > >      is always protect none.
> > > (3) if there is an overflow because there are no more free slots
> > > for
> > >      further settings (for 3 bits with flashes > 32MBit, for 4
> > >      bits if should be flashes > 16GBit), the first entry will be
> > >      discarded (eg the very first is the "just one sector"
> > > entry).
> > > 
> > > This is true for all flashes which uses this kind of setting,
> > > have a
> > > look at the m25p80 or w25q40bw, these are no exception. It is
> > > just
> > > the
> > > notation "lower 1/64" which is only true for flashes which either
> > > overflows in (3) or fill all entries (eg. with 3bits that would
> > > be
> > > the
> > > 32Mbit version).
> > > 
> > 
> > Looks like you noticed that we need new calculation method that
> > would
> > be based on n_sectors :).
> 
> No it will work without that (if I'm not mistaken). Give me some time
> and I'll post a patch.

No, it must be based on n_sectors. To make 4bit block protection more
generic, the lock sector size must NOT fixed as 64KB (as can be checked
from your patch). See "mt35xu02g" and check the protected area and
number of sectors from it's datasheet.

The rule you mentioned "the first setting (besides 0) protects one
sector" is alawys true for *4bit* block protection. That's why I choose
n_sectors for new calculation.

> 
> > Rule (1) is NOT true for some flashes
> > supporting BP0-2 and that's why I said that smallest protected
> > portion
> > is fixed as '1/64' for these flashes.
> 
> No, you have to apply rule (3). (1) is only the starting point. It
> is 
> kind
> of a sliding window.
> 
> > See this one.
> > 
> > W25Q20EW	256KB	1/4 ... = 64KB		BP2
> > W25Q128JV	16MB	1/64 ... = 256KB	BP2 <--
> > S25FL132K	4MB	1/64 ... = 64KB		BP2 <--
> > S25FL164K	8MB
> > 1/64 ... = 128KB	BP2 <--
> 
> All these flashes need (3) to be applied, thus (1) doesn't apply
> anymore.
> 
> Let me give you an example for the 64MBit case, the settings would
> be:
> 
> 0 sectors (corresponds to protect none)
> 1 sector
> 2 sectors
> 4 sectors
> 8 sectors
> 16 sectors
> 32 sectors
> 64 sectors
> 128 sectors (corresponds to protect all)
> 
> Unfortunately, we have only 8 slots (because 3 BP bits), therefore
> we 
> have
> to discard some setting. According to rule (2) 0 is always "protect 
> none"
> and 7 is always "protect all". Thus we have 6 settings left.
> According 
> to
> rule (3) we discard the first ones. In this case, this is the "1
> sector"
> setting. Thus we end up with the following possible settings:
> 
> 0 sectors (corresponds to protect none)
> 2 sectors
> 4 sectors
> 8 sectors
> 16 sectors
> 32 sectors
> 64 sectors
> 128 sectors (corresponds to protect all)
> 
> If you have a 128Mbit flash, the next setting that would be discarded
> is
> "2 sectors". Thus it would start with:
> 
> 0 sectors (corresponds to protect none)
> 4 sectors
> [..]
> 256 sectors (corresponds to protect all)
> 
> 
> Another example W25Q20EW, following possible settings:
> 
> 0 sectors (corresponds to protect none)
> 1 sector
> 2 sectors
> 4 sectors (corresponds to protect all)
> 
> We now have less settings then our 8 possible slots. So this is where
> rule (1) applies, because according to that the "1 sector" setting is
> the first possible setting besides 0.
> 
> And this also applies to the 4 bit protection bits.
> 
> 
> 
> > W25Q256JV	32MB	1/512 ... =
> > 64KB	BP3
> > S25FL128L	16MB	1/256 ... = 64KB	BP3
> > S25FL256L	32MB	1/512 ... = 64KB	BP3
> > 
> > In current BP implementation, block protection is just working for
> > some
> > flashes that has smallest protected portion as '1/64'.
> 
> No its currently working for all except flashes smaller than 32Mbit.

No. Not working for flashes supporting 4bit block protection.

> Applied to the 4 bits, this would mean "it works for all except
> flashes
> smaller than 8Gbit" which are practially all. As I said, this is a
> bug
> and once this bug is fixed, there should be no difference between 3
> and 4 bits.
> 
> -michael
> 

The exact fact is that locks operate in two different ways according to
flash model.

(1) the smallest protected portion is fixed.
	for BP0-2 : 1/64
	for BP0-1 : 1/4
(2) the smallest protected portion is inversely propotional with number
of sectors.

For the flashes supporting 3bit block protection, (1) and (2) are mixed
and used. But all the flashes supporting 4bit block protection listed
on spi-nor.c, only (2) is used.

Each method requires each formula. I have no idea how to handle it with
one formula (probably adding number of exceptional handling?) without
any sectional flag. "w25q128jv(bp0-2)" is following (1) and
"n25q128a(bp0-3)" is following (2).

> > 
> > We need new fomula based on n_sectors for BP3 at least.
> 
> No they are the same, but yes there is a bug in the current
> implementation.
> 
> -michael
> 
> > 
> > > So for the 3 bit case the following flashes are border cases:
> > >   - 16mbit (less settings than slots)
> > >   - 32mbit (number of settings and free slots match)
> > >   - 64mbit (more settings than slots, first setting is discarded)
> > > 
> > > That being said, I suspect all the 16mbit flashes (and below)
> > > which
> > > have
> > > the _LOCK bit set are broken, because the entries has to be
> > > shifted.
> > > I'll
> > > look into that later. This is the same "issue" you have with the
> > > 4
> > > bits.
> > > So if this is fixed, you should not need another formula for the
> > > 4
> > > bit
> > > case.
> > > 
> > > > We need new calculation method for 4bit block protection and
> > > > for
> > > > making
> > > > it more generic, I choose n_sectors.
> > > > 
> > > > On all the flashes I checked, n_sectors is proper value for
> > > > getting
> > > > block protected portion.
> > > > 
> > > > 		density	portion	n_sectors
> > > > W25M512JV	64MB	1/512	512
> > > > N25Q128A	16MB	1/256	256
> > > > N25Q512A	64MB	1/1024	1024
> > > > MT25QL02GCBB	256MB	1/4096	4096
> > > 
> > > The rules above apply to these flashes, too. Could you double
> > > check
> > > that?
> > > 
> > > -michael
> > > 
> > > > 
> > > > > > +		val = val << SR_BP_SHIFT;
> > > > > > +
> > > > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
> > > > > > +			val = (val & ~BIT(5)) | BIT(6);
> > > > > > +	} else {
> > > > > > +		val = mask - (pow << SR_BP_SHIFT);
> > > > > > +	}
> > > > > > +
> > > > > >  	if (val & ~mask)
> > > > > >  		return -EINVAL;
> > > > > >  	/* Don't "lock" with no region! */
> > > > > > @@ -1983,6 +2057,13 @@ static int stm_unlock(struct spi_nor
> > > > > > *nor,
> > > > > > loff_t ofs, uint64_t len)
> > > > > > 
> > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> > > > > >  		tb_mask = SR_TB_BIT6;
> > > > > > +
> > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
> > > > > > +			mask = mask | SR_BP3_BIT6;
> > > > > > +		else
> > > > > > +			mask = mask | SR_BP3_BIT5;
> > > > > > +	}
> > > > > >  	/*
> > > > > >  	 * Need largest pow such that:
> > > > > >  	 *
> > > > > > @@ -1995,13 +2076,20 @@ static int stm_unlock(struct
> > > > > > spi_nor
> > > > > > *nor,
> > > > > > loff_t ofs, uint64_t len)
> > > > > >  	pow = ilog2(mtd->size) - order_base_2(lock_len);
> > > > > >  	if (lock_len == 0) {
> > > > > >  		val = 0; /* fully unlocked */
> > > > > > +	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
> > > > > > +		val = val << SR_BP_SHIFT;
> > > > > > +
> > > > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
> > > > > > +			val = (val & ~BIT(5)) | BIT(6);
> > > > > >  	} else {
> > > > > >  		val = mask - (pow << SR_BP_SHIFT);
> > > > > > -		/* Some power-of-two sizes are not supported */
> > > > > > -		if (val & ~mask)
> > > > > > -			return -EINVAL;
> > > > > >  	}
> > > > > > 
> > > > > > +	/* Some power-of-two sizes are not supported */
> > > > > > +	if (val & ~mask)
> > > > > > +		return -EINVAL;
> > > > > > +
> > > > > >  	status_new = (status_old & ~mask & ~tb_mask) | val;
> > > > > > 
> > > > > >  	/* Don't protect status register if we're fully
> > > > > > unlocked */
> > > > > > @@ -4736,6 +4824,7 @@ static void
> > > > > > spi_nor_info_init_params(struct
> > > > > > spi_nor *nor)
> > > > > >  	/* Set SPI NOR sizes. */
> > > > > >  	params->size = (u64)info->sector_size * info-
> > > > > > > n_sectors;
> > > > > > 
> > > > > >  	params->page_size = info->page_size;
> > > > > > +	params->n_sectors = info->n_sectors;
> > > > > > 
> > > > > >  	if (!(info->flags & SPI_NOR_NO_FR)) {
> > > > > >  		/* Default to Fast Read for DT and non-DT
> > > > > > platform
> > > > > > devices. */
> > > > > > @@ -5192,6 +5281,11 @@ int spi_nor_scan(struct spi_nor
> > > > > > *nor,
> > > > > > const
> > > > > > char *name,
> > > > > >  		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
> > > > > >  	if (info->flags & USE_CLSR)
> > > > > >  		nor->flags |= SNOR_F_USE_CLSR;
> > > > > > +	if (info->flags & SPI_NOR_HAS_BP3) {
> > > > > > +		nor->flags |= SNOR_F_HAS_SR_BP3;
> > > > > > +		if (info->flags & SPI_NOR_BP3_SR_BIT6)
> > > > > > +			nor->flags |= SNOR_F_HAS_SR_BP3_BIT6;
> > > > > > +	}
> > > > > > 
> > > > > >  	if (info->flags & SPI_NOR_NO_ERASE)
> > > > > >  		mtd->flags |= MTD_NO_ERASE;
> > > > > > @@ -5199,6 +5293,7 @@ int spi_nor_scan(struct spi_nor *nor,
> > > > > > const
> > > > > > char *name,
> > > > > >  	mtd->dev.parent = dev;
> > > > > >  	nor->page_size = params->page_size;
> > > > > >  	mtd->writebufsize = nor->page_size;
> > > > > > +	nor->n_sectors = params->n_sectors;
> > > > > > 
> > > > > >  	if (of_property_read_bool(np, "broken-flash-reset"))
> > > > > >  		nor->flags |= SNOR_F_BROKEN_RESET;
> > > > > > diff --git a/include/linux/mtd/spi-nor.h
> > > > > > b/include/linux/mtd/spi-
> > > > > > nor.h
> > > > > > index 541c06d042e8..92d550501daf 100644
> > > > > > --- a/include/linux/mtd/spi-nor.h
> > > > > > +++ b/include/linux/mtd/spi-nor.h
> > > > > > @@ -129,7 +129,9 @@
> > > > > >  #define SR_BP1			BIT(3)	/* Block
> > > > > > protect 1
> > > > > > */
> > > > > >  #define SR_BP2			BIT(4)	/* Block
> > > > > > protect 2
> > > > > > */
> > > > > >  #define SR_TB_BIT5		BIT(5)	/* Top/Bottom
> > > > > > protect
> > > > > > */
> > > > > > +#define SR_BP3_BIT5		BIT(5)	/* Block
> > > > > > protect 3
> > > > > > */
> > > > > 
> > > > > maybe just name it SR_BP3? would also be more consistent with
> > > > > the
> > > > > proposal
> > > > > above.
> > > > > 
> > > > > >  #define SR_TB_BIT6		BIT(6)	/* Top/Bottom
> > > > > > protect
> > > > > > */
> > > > > > +#define SR_BP3_BIT6		BIT(6)	/* Block
> > > > > > protect 3
> > > > > > */
> > > > > >  #define SR_SRWD			BIT(7)	/* SR write
> > > > > > protect
> > > > > > */
> > > > > >  /* Spansion/Cypress specific status bits */
> > > > > >  #define SR_E_ERR		BIT(5)
> > > > > > @@ -248,6 +250,8 @@ enum spi_nor_option_flags {
> > > > > >  	SNOR_F_HAS_16BIT_SR	= BIT(9),
> > > > > >  	SNOR_F_NO_READ_CR	= BIT(10),
> > > > > >  	SNOR_F_HAS_SR_TB_BIT6	= BIT(11),
> > > > > > +	SNOR_F_HAS_SR_BP3	= BIT(12),
> > > > > > +	SNOR_F_HAS_SR_BP3_BIT6	= BIT(13),
> > > > > > 
> > > > > >  };
> > > > > > 
> > > > > > @@ -519,6 +523,7 @@ struct spi_nor_locking_ops {
> > > > > >   *
> > > > > >   * @size:		the flash memory density in bytes.
> > > > > >   * @page_size:		the page size of the SPI NOR
> > > > > > flash
> > > > > > memory.
> > > > > > + * @n_sectors:		number of sectors
> > > > > >   * @hwcaps:		describes the read and page
> > > > > > program
> > > > > > hardware
> > > > > >   *			capabilities.
> > > > > >   * @reads:		read capabilities ordered by priority:
> > > > > > the
> > > > > > higher index
> > > > > > @@ -541,6 +546,7 @@ struct spi_nor_locking_ops {
> > > > > >  struct spi_nor_flash_parameter {
> > > > > >  	u64				size;
> > > > > >  	u32				page_size;
> > > > > > +	u16				n_sectors;
> > > > > > 
> > > > > >  	struct spi_nor_hwcaps		hwcaps;
> > > > > >  	struct spi_nor_read_command	reads[SNOR_CMD_READ_MAX
> > > > > > ];
> > > > > > @@ -573,6 +579,7 @@ struct flash_info;
> > > > > >   * @bouncebuf_size:	size of the bounce buffer
> > > > > >   * @info:		spi-nor part JDEC MFR id and other info
> > > > > >   * @page_size:		the page size of the SPI NOR
> > > > > > + * @n_sector:		number of sectors
> > > > > >   * @addr_width:		number of address bytes
> > > > > >   * @erase_opcode:	the opcode for erasing a sector
> > > > > >   * @read_opcode:	the read opcode
> > > > > > @@ -599,6 +606,7 @@ struct spi_nor {
> > > > > >  	size_t			bouncebuf_size;
> > > > > >  	const struct flash_info	*info;
> > > > > >  	u32			page_size;
> > > > > > +	u16			n_sectors;
> > > > > >  	u8			addr_width;
> > > > > >  	u8			erase_opcode;
> > > > > >  	u8			read_opcode;
> > > > > > --
> > > > > > 2.17.1
> > > > > > 
> > > > > > 
> > > > > > ______________________________________________________
> > > > > > Linux MTD discussion mailing list
> > > > > > 
> > > > 
> > > > 
> > 
> > 
https://protect2.fireeye.com/url?k=06b6dd5d-5b7d5a63-06b75612-0cc47a31309a-83164929001f7741&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
> > > > > > 
> > > > > 
> > > > > 
> > > 
> > > 
> 
> 


______________________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-mtd/

[SPAM] Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Am 2020-01-28 12:01, schrieb Jungseung Lee:
> Hi, Michael
> 
> 2020-01-23 (Thu), 10:31 +0100, Michael Walle:
>> Am 2020-01-23 09:53, schrieb Jungseung Lee:
>> > Hi, Michael
>> >
>> > 2020-01-23 (Thu), 09:10 +0100, Michael Walle:
>> > > Hi Jungseung,
>> > >
>> > > Am 2020-01-23 07:22, schrieb Jungseung Lee:
>> > > > Hi, Michael
>> > > >
>> > > > 2020-01-22 (Wed), 20:36 +0100, Michael Walle:
>> > > > > Hi,
>> > > > >
>> > > > > > Currently, we are supporting block protection only for
>> > > > > > flash chips with 3 block protection bits in the SR
>> > > > > > register.
>> > > > > > This patch enables block protection support for some flash
>> > > > > > with
>> > > > > > 4 block protection bits(bp0-3).
>> > > > > >
>> > > > > > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
>> > > > > > ---
>> > > > > > v3 :
>> > > > > >   Fix wrong ofs calculation on v2 patch
>> > > > > > v2 :
>> > > > > >   Add sample table portion about 4bit block protection on
>> > > > > > the
>> > > > > > comment
>> > > > > >   Trivial coding style change
>> > > > > >
>> > > > > >  drivers/mtd/spi-nor/spi-nor.c | 127
>> > > > > > +++++++++++++++++++++++++++++-
>> > > > > > ----
>> > > > > >  include/linux/mtd/spi-nor.h   |   8 +++
>> > > > > >  2 files changed, 119 insertions(+), 16 deletions(-)
>> > > > > >
>> > > > > > diff --git a/drivers/mtd/spi-nor/spi-nor.c
>> > > > > > b/drivers/mtd/spi-
>> > > > > > nor/spi-nor.c
>> > > > > > index e3da6a8654a8..7e8af6c4fdfa 100644
>> > > > > > --- a/drivers/mtd/spi-nor/spi-nor.c
>> > > > > > +++ b/drivers/mtd/spi-nor/spi-nor.c
>> > > > > > @@ -238,6 +238,14 @@ struct flash_info {
>> > > > > >  					 * status register.
>> > > > > > Must be
>> > > > > > used with
>> > > > > >  					 * SPI_NOR_HAS_TB.
>> > > > > >  					 */
>> > > > > > +#define SPI_NOR_HAS_BP3		BIT(17)	/*
>> > > > > > +					 * Flash SR has 4 bit
>> > > > > > fields
>> > > > > > (BP0-3)
>> > > > > > +					 * for block
>> > > > > > protection.
>> > > > > > +					 */
>> > > > > > +#define SPI_NOR_BP3_SR_BIT6	BIT(18)	/*
>> > > > > > +					 * BP3 is bit 6 of
>> > > > > > status
>> > > > > > register.
>> > > > > > +					 * Must be used with
>> > > > > > SPI_NOR_HAS_BP3.
>> > > > > > +					 */
>> > > > > >
>> > > > > >  	/* Part specific fixup hooks. */
>> > > > > >  	const struct spi_nor_fixups *fixups;
>> > > > > > @@ -1767,23 +1775,47 @@ static void
>> > > > > > stm_get_locked_range(struct
>> > > > > > spi_nor *nor, u8 sr, loff_t *ofs,
>> > > > > >  	struct mtd_info *mtd = &nor->mtd;
>> > > > > >  	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
>> > > > > >  	u8 tb_mask = SR_TB_BIT5;
>> > > > > > -	int pow;
>> > > > > > +	u8 bp;
>> > > > > > +	int pow = 0;
>> > > > > >
>> > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>> > > > > >  		tb_mask = SR_TB_BIT6;
>> > > > > >
>> > > > > > -	if (!(sr & mask)) {
>> > > > > > -		/* No protection */
>> > > > > > -		*ofs = 0;
>> > > > > > -		*len = 0;
>> > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > > > +		u8 tmp;
>> > > > > > +
>> > > > > > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
>> > > > > > +			tmp = sr & (mask | SR_BP3_BIT6);
>> > > > > > +		else
>> > > > > > +			tmp = sr & (mask | SR_BP3_BIT5);
>> > > > > > +
>> > > > > > +		if (tmp & SR_BP3_BIT6)
>> > > > > > +			tmp = (tmp & ~BIT(6)) | BIT(5);
>> > > > > > +
>> > > > > > +		bp = tmp >> SR_BP_SHIFT;
>> > > > > > +		if (!bp) {
>> > > > > > +			*ofs = 0;
>> > > > > > +			*len = 0;
>> > > > > > +			return;
>> > > > > > +		}
>> > > > > > +		if (bp <= ilog2(nor->n_sectors))
>> > > > > > +			pow = ilog2(nor->n_sectors) + 1 - bp;
>> > > > > >  	} else {
>> > > > > > -		pow = ((sr & mask) ^ mask) >> SR_BP_SHIFT;
>> > > > > > -		*len = mtd->size >> pow;
>> > > > > > -		if (nor->flags & SNOR_F_HAS_SR_TB && sr &
>> > > > > > tb_mask)
>> > > > > > +		bp = (sr & mask) >> SR_BP_SHIFT;
>> > > > > > +		if (!bp) {
>> > > > > >  			*ofs = 0;
>> > > > > > -		else
>> > > > > > -			*ofs = mtd->size - *len;
>> > > > > > +			*len = 0;
>> > > > > > +			return;
>> > > > > > +		}
>> > > > > > +		pow = bp ^ (mask >> SR_BP_SHIFT);
>> > > > > >  	}
>> > > > > > +
>> > > > > > +	*len = mtd->size >> pow;
>> > > > > > +
>> > > > > > +	if (nor->flags & SNOR_F_HAS_SR_TB && sr & tb_mask)
>> > > > > > +		*ofs = 0;
>> > > > > > +	else
>> > > > > > +		*ofs = mtd->size - *len;
>> > > > > >  }
>> > > > > >
>> > > > > >  /*
>> > > > > > @@ -1823,7 +1855,7 @@ static int stm_is_unlocked_sr(struct
>> > > > > > spi_nor
>> > > > > > *nor, loff_t ofs, uint64_t len,
>> > > > > >
>> > > > > >  /*
>> > > > > >   * Lock a region of the flash. Compatible with ST Micro
>> > > > > > and
>> > > > > > similar flash.
>> > > > > > - * Supports the block protection bits BP{0,1,2} in the
>> > > > > > status
>> > > > > > register
>> > > > > > + * Supports the block protection bits BP{0,1,2,3} in the
>> > > > > > status
>> > > > > > register
>> > > > > >   * (SR). Does not support these features found in newer SR
>> > > > > > bitfields:
>> > > > > >   *   - SEC: sector/block protect - only handle SEC=0
>> > > > > > (block
>> > > > > > protect)
>> > > > > >   *   - CMP: complement protect - only support CMP=0 (range
>> > > > > > is
>> > > > > > not
>> > > > > > complemented)
>> > > > > > @@ -1831,7 +1863,7 @@ static int stm_is_unlocked_sr(struct
>> > > > > > spi_nor
>> > > > > > *nor, loff_t ofs, uint64_t len,
>> > > > > >   * Support for the following is provided conditionally for
>> > > > > > some
>> > > > > > flash:
>> > > > > >   *   - TB: top/bottom protect
>> > > > > >   *
>> > > > > > - * Sample table portion for 8MB flash (Winbond w25q64fw):
>> > > > > > + * Sample table portion for 8MB flash (Winbond w25q64fw /
>> > > > > > BP0-
>> > > > > > 2):
>> > > > > >   *
>> > > > > >   *   SEC  |  TB   |  BP2  |  BP1  |  BP0  |  Prot
>> > > > > > Length  |
>> > > > > > Protected Portion
>> > > > > >   *  ----------------------------------------------------
>> > > > > > ----
>> > > > > > ----
>> > > > > > --------------
>> > > > > > @@ -1851,6 +1883,32 @@ static int stm_is_unlocked_sr(struct
>> > > > > > spi_nor
>> > > > > > *nor, loff_t ofs, uint64_t len,
>> > > > > >   *    0   |   1   |   1   |   0   |   1   |  2
>> > > > > > MB         |
>> > > > > > Lower
>> > > > > > 1/4
>> > > > > >   *    0   |   1   |   1   |   1   |   0   |  4
>> > > > > > MB         |
>> > > > > > Lower
>> > > > > > 1/2
>> > > > > >   *
>> > > > > > + * Sample table portion for 64MB flash (Micron n25q512ax3
>> > > > > > /
>> > > > > > BP0-
>> > > > > > 3):
>> > > > > > + *
>> > > > > > + *   TB   |  BP3  |  BP2  |  BP1  |  BP0  |  Prot
>> > > > > > Length  |
>> > > > > > Protected Portion
>> > > > > > + *  ----------------------------------------------------
>> > > > > > ----
>> > > > > > ----
>> > > > > > --------------
>> > > > > > +
>> > > > > > *    0   |   0   |   0   |   0   |   0   |  NONE         |
>> > > > > > NONE
>> > > > > > + *    0   |   0   |   0   |   0   |   1   |   64
>> > > > > > KB       |
>> > > > > > Upper
>> > > > > > 1/1024
>> > > > > > + *    0   |   0   |   0   |   1   |   0   |  128
>> > > > > > KB       |
>> > > > > > Upper
>> > > > > > 1/512
>> > > > > > + *    0   |   0   |   0   |   1   |   1   |  256
>> > > > > > KB       |
>> > > > > > Upper
>> > > > > > 1/256
>> > > > > > + *   ...
>> > > > > > + *    0   |   1   |   0   |   0   |   1   |  16
>> > > > > > MB        |
>> > > > > > Upper
>> > > > > > 1/4
>> > > > > > + *    0   |   1   |   0   |   1   |   0   |  32
>> > > > > > MB        |
>> > > > > > Upper
>> > > > > > 1/2
>> > > > > > + *    0   |   1   |   0   |   1   |   1   |  64
>> > > > > > MB        |
>> > > > > > ALL
>> > > > > > + *    0   |   1   |   1   |   0   |   0   |  64
>> > > > > > MB        |
>> > > > > > ALL
>> > > > > > + *   ...
>> > > > > > + *  ------|-------|-------|-------|-------|---------------
>> > > > > > |---
>> > > > > > ----
>> > > > > > ------------
>> > > > > > +
>> > > > > > *    1   |   0   |   0   |   0   |   0   |   NONE        |
>> > > > > > NONE
>> > > > > > + *    1   |   0   |   0   |   0   |   1   |   64
>> > > > > > KB       |
>> > > > > > Lower
>> > > > > > 1/1024
>> > > > > > + *    1   |   0   |   0   |   1   |   0   |  128
>> > > > > > KB       |
>> > > > > > Lower
>> > > > > > 1/512
>> > > > > > + *    1   |   0   |   0   |   1   |   1   |  256
>> > > > > > KB       |
>> > > > > > Lower
>> > > > > > 1/256
>> > > > > > + *   ...
>> > > > > > + *    1   |   1   |   0   |   0   |   1   |  16
>> > > > > > MB        |
>> > > > > > Lower
>> > > > > > 1/4
>> > > > > > + *    1   |   1   |   0   |   1   |   0   |  32
>> > > > > > MB        |
>> > > > > > Lower
>> > > > > > 1/2
>> > > > > > + *    1   |   1   |   0   |   1   |   1   |  64
>> > > > > > MB        |
>> > > > > > ALL
>> > > > > > + *    1   |   1   |   1   |   0   |   0   |  64
>> > > > > > MB        |
>> > > > > > ALL
>> > > > > > + *   ...
>> > > > > > + *
>> > > > > >   * Returns negative on errors, 0 on success.
>> > > > > >   */
>> > > > > >  static int stm_lock(struct spi_nor *nor, loff_t ofs,
>> > > > > > uint64_t
>> > > > > > len)
>> > > > > > @@ -1898,6 +1956,12 @@ static int stm_lock(struct spi_nor
>> > > > > > *nor,
>> > > > > > loff_t ofs, uint64_t len)
>> > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>> > > > > >  		tb_mask = SR_TB_BIT6;
>> > > > > >
>> > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > > > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
>> > > > > > +			mask = mask | SR_BP3_BIT6;
>> > > > > > +		else
>> > > > > > +			mask = mask | SR_BP3_BIT5;
>> > > > > > +	}
>> > > > > >  	/*
>> > > > > >  	 * Need smallest pow such that:
>> > > > > >  	 *
>> > > > > > @@ -1908,7 +1972,17 @@ static int stm_lock(struct spi_nor
>> > > > > > *nor,
>> > > > > > loff_t ofs, uint64_t len)
>> > > > > >  	 *   pow = ceil(log2(size / len)) = log2(size) -
>> > > > > > floor(log2(len))
>> > > > > >  	 */
>> > > > > >  	pow = ilog2(mtd->size) - ilog2(lock_len);
>> > > > > > -	val = mask - (pow << SR_BP_SHIFT);
>> > > > > > +
>> > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
>> > > > >
>> > > > > Why do you use a new calculation here? As far as I can see,
>> > > > > the
>> > > > > method is
>> > > > > the same except that is has one bit more. That also raises
>> > > > > the
>> > > > > question why
>> > > > > n_sectors is now needed?
>> > > > >
>> > > > > Can't we just initialize the mask with
>> > > > >
>> > > > > mask = SR_BP2 | SR_BP1 | SR_BP0;
>> > > > > if (nor->flags & SNOR_F_HAS_SR_BP3)
>> > > > >     mask |= SR_BP3_BIT5;
>> > > > >
>> > > > > do the calculation and checks and then move the SR_BP3_BIT5
>> > > > > to
>> > > > > SR_BP3_BIT6
>> > > > > if SNOR_F_HAS_SR_BP3_BIT6 is set.
>> > > > >
>> > > >
>> > > > For most of flashes that supporting BP0-2, the smallest
>> > > > protected
>> > > > portion is fixed as 1/64
>> > > > and it can be properly handled by existing
>> > > > calculation. (Actually it's not fully generic, see flashes like
>> > > > w25q40bw or m25p80. Of course, it doesn't have SPI_NOR_HAS_LOCK
>> > > > flag
>> > > > even though it has BP0-2 bit in SR)
>> > >
>> > > No. The rules are always the same wether there are three or four
>> > > BP
>> > > bits (the example in stm_lock() has not enough information on
>> > > this):
>> > >
>> > > (1) the first setting (besides 0) protects one sector. The second
>> > >      protects 2, the third 4 and so on. eg 2^N
>> > > (2) the last setting is _always_ protect all, just like the '0'
>> > > setting
>> > >      is always protect none.
>> > > (3) if there is an overflow because there are no more free slots
>> > > for
>> > >      further settings (for 3 bits with flashes > 32MBit, for 4
>> > >      bits if should be flashes > 16GBit), the first entry will be
>> > >      discarded (eg the very first is the "just one sector"
>> > > entry).
>> > >
>> > > This is true for all flashes which uses this kind of setting,
>> > > have a
>> > > look at the m25p80 or w25q40bw, these are no exception. It is
>> > > just
>> > > the
>> > > notation "lower 1/64" which is only true for flashes which either
>> > > overflows in (3) or fill all entries (eg. with 3bits that would
>> > > be
>> > > the
>> > > 32Mbit version).
>> > >
>> >
>> > Looks like you noticed that we need new calculation method that
>> > would
>> > be based on n_sectors :).
>> 
>> No it will work without that (if I'm not mistaken). Give me some time
>> and I'll post a patch.
> 
> No, it must be based on n_sectors. To make 4bit block protection more
> generic, the lock sector size must NOT fixed as 64KB (as can be checked
> from your patch). See "mt35xu02g" and check the protected area and
> number of sectors from it's datasheet.

There is no public datasheet as far as I can see. And yes, actually
n_sectors is my "mtd-size / sector_size". But I don't see how n_sectors
would help if the sector size changes.

> The rule you mentioned "the first setting (besides 0) protects one
> sector" is alawys true for *4bit* block protection. That's why I choose
> n_sectors for new calculation.

And how does flashes behave once all the free slots are full? It was the
same with the 3bit flashes, they only overflowed with "newer"/bigger
flashes.


>> 
>> > Rule (1) is NOT true for some flashes
>> > supporting BP0-2 and that's why I said that smallest protected
>> > portion
>> > is fixed as '1/64' for these flashes.
>> 
>> No, you have to apply rule (3). (1) is only the starting point. It
>> is
>> kind
>> of a sliding window.
>> 
>> > See this one.
>> >
>> > W25Q20EW	256KB	1/4 ... = 64KB		BP2
>> > W25Q128JV	16MB	1/64 ... = 256KB	BP2 <--
>> > S25FL132K	4MB	1/64 ... = 64KB		BP2 <--
>> > S25FL164K	8MB
>> > 1/64 ... = 128KB	BP2 <--
>> 
>> All these flashes need (3) to be applied, thus (1) doesn't apply
>> anymore.
>> 
>> Let me give you an example for the 64MBit case, the settings would
>> be:
>> 
>> 0 sectors (corresponds to protect none)
>> 1 sector
>> 2 sectors
>> 4 sectors
>> 8 sectors
>> 16 sectors
>> 32 sectors
>> 64 sectors
>> 128 sectors (corresponds to protect all)
>> 
>> Unfortunately, we have only 8 slots (because 3 BP bits), therefore
>> we
>> have
>> to discard some setting. According to rule (2) 0 is always "protect
>> none"
>> and 7 is always "protect all". Thus we have 6 settings left.
>> According
>> to
>> rule (3) we discard the first ones. In this case, this is the "1
>> sector"
>> setting. Thus we end up with the following possible settings:
>> 
>> 0 sectors (corresponds to protect none)
>> 2 sectors
>> 4 sectors
>> 8 sectors
>> 16 sectors
>> 32 sectors
>> 64 sectors
>> 128 sectors (corresponds to protect all)
>> 
>> If you have a 128Mbit flash, the next setting that would be discarded
>> is
>> "2 sectors". Thus it would start with:
>> 
>> 0 sectors (corresponds to protect none)
>> 4 sectors
>> [..]
>> 256 sectors (corresponds to protect all)
>> 
>> 
>> Another example W25Q20EW, following possible settings:
>> 
>> 0 sectors (corresponds to protect none)
>> 1 sector
>> 2 sectors
>> 4 sectors (corresponds to protect all)
>> 
>> We now have less settings then our 8 possible slots. So this is where
>> rule (1) applies, because according to that the "1 sector" setting is
>> the first possible setting besides 0.
>> 
>> And this also applies to the 4 bit protection bits.
>> 
>> 
>> 
>> > W25Q256JV	32MB	1/512 ... =
>> > 64KB	BP3
>> > S25FL128L	16MB	1/256 ... = 64KB	BP3
>> > S25FL256L	32MB	1/512 ... = 64KB	BP3
>> >
>> > In current BP implementation, block protection is just working for
>> > some
>> > flashes that has smallest protected portion as '1/64'.
>> 
>> No its currently working for all except flashes smaller than 32Mbit.
> 
> No. Not working for flashes supporting 4bit block protection.
> 
>> Applied to the 4 bits, this would mean "it works for all except
>> flashes
>> smaller than 8Gbit" which are practially all. As I said, this is a
>> bug
>> and once this bug is fixed, there should be no difference between 3
>> and 4 bits.
>> 
>> -michael
>> 
> 
> The exact fact is that locks operate in two different ways according to
> flash model.
> 
> (1) the smallest protected portion is fixed.
> 	for BP0-2 : 1/64
> 	for BP0-1 : 1/4

As mentioned earlier, the ratio nomenclature is missleading and only 
valid
if the table is completely filled up.

Take a flash with 128kB and three BP bits (or even only two BP bits). 
The
smallest portion will be 64kB (which is one sector and not 1/64).

Thus the smallest portion is always one sector, unless the table is
overflowing, then the smallest will settle to 1/4 (for two), 1/64 (for 
three)
and 1/16384 (for four bits).

> (2) the smallest protected portion is inversely propotional with number
> of sectors.
> 
> For the flashes supporting 3bit block protection, (1) and (2) are mixed
> and used. But all the flashes supporting 4bit block protection listed
> on spi-nor.c, only (2) is used.

It is not mixed it just depends on the flash size (and the number of
protection bits).

> Each method requires each formula. I have no idea how to handle it with
> one formula (probably adding number of exceptional handling?) without
> any sectional flag. "w25q128jv(bp0-2)" is following (1) and
> "n25q128a(bp0-3)" is following (2).

Well one uses three BPs the other four, and they all follow the three 
rules
above. Did you try my patch? Because I've (at least in userspace) tested
it with 4 bits and got the correct results.

And yes, its actually two different formulas, but not for 3 and 4 bits 
like
in your patch. It is rather one formula (A) for flashes which don't 
exhaust
the BP bits (eg. for 3 bits this would be flashes <= 16Mbit and for 4 
bits
this would be for flashes <=8Gbit) and one (B) for the flashes where 
every
BP bit combination is used. What is at the moment in the kernel is the
second one, thus it will fail for flashes <= 16Mbit and 3 BP bits; and 
it
also fails for all flashes with 4 bits. My patch does a fixup on (B) to
match the results of (A), because doing this is less invasive; and as
mentioned in the patch annex, might also be rewritten for a better
understanding.


-michael

> 
>> >
>> > We need new fomula based on n_sectors for BP3 at least.
>> 
>> No they are the same, but yes there is a bug in the current
>> implementation.
>> 
>> -michael
>> 
>> >
>> > > So for the 3 bit case the following flashes are border cases:
>> > >   - 16mbit (less settings than slots)
>> > >   - 32mbit (number of settings and free slots match)
>> > >   - 64mbit (more settings than slots, first setting is discarded)
>> > >
>> > > That being said, I suspect all the 16mbit flashes (and below)
>> > > which
>> > > have
>> > > the _LOCK bit set are broken, because the entries has to be
>> > > shifted.
>> > > I'll
>> > > look into that later. This is the same "issue" you have with the
>> > > 4
>> > > bits.
>> > > So if this is fixed, you should not need another formula for the
>> > > 4
>> > > bit
>> > > case.
>> > >
>> > > > We need new calculation method for 4bit block protection and
>> > > > for
>> > > > making
>> > > > it more generic, I choose n_sectors.
>> > > >
>> > > > On all the flashes I checked, n_sectors is proper value for
>> > > > getting
>> > > > block protected portion.
>> > > >
>> > > > 		density	portion	n_sectors
>> > > > W25M512JV	64MB	1/512	512
>> > > > N25Q128A	16MB	1/256	256
>> > > > N25Q512A	64MB	1/1024	1024
>> > > > MT25QL02GCBB	256MB	1/4096	4096
>> > >
>> > > The rules above apply to these flashes, too. Could you double
>> > > check
>> > > that?
>> > >
>> > > -michael
>> > >
>> > > >
>> > > > > > +		val = val << SR_BP_SHIFT;
>> > > > > > +
>> > > > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
>> > > > > > +			val = (val & ~BIT(5)) | BIT(6);
>> > > > > > +	} else {
>> > > > > > +		val = mask - (pow << SR_BP_SHIFT);
>> > > > > > +	}
>> > > > > > +
>> > > > > >  	if (val & ~mask)
>> > > > > >  		return -EINVAL;
>> > > > > >  	/* Don't "lock" with no region! */
>> > > > > > @@ -1983,6 +2057,13 @@ static int stm_unlock(struct spi_nor
>> > > > > > *nor,
>> > > > > > loff_t ofs, uint64_t len)
>> > > > > >
>> > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>> > > > > >  		tb_mask = SR_TB_BIT6;
>> > > > > > +
>> > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > > > +		if (nor->flags & SNOR_F_HAS_SR_BP3_BIT6)
>> > > > > > +			mask = mask | SR_BP3_BIT6;
>> > > > > > +		else
>> > > > > > +			mask = mask | SR_BP3_BIT5;
>> > > > > > +	}
>> > > > > >  	/*
>> > > > > >  	 * Need largest pow such that:
>> > > > > >  	 *
>> > > > > > @@ -1995,13 +2076,20 @@ static int stm_unlock(struct
>> > > > > > spi_nor
>> > > > > > *nor,
>> > > > > > loff_t ofs, uint64_t len)
>> > > > > >  	pow = ilog2(mtd->size) - order_base_2(lock_len);
>> > > > > >  	if (lock_len == 0) {
>> > > > > >  		val = 0; /* fully unlocked */
>> > > > > > +	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
>> > > > > > +		val = val << SR_BP_SHIFT;
>> > > > > > +
>> > > > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
>> > > > > > +			val = (val & ~BIT(5)) | BIT(6);
>> > > > > >  	} else {
>> > > > > >  		val = mask - (pow << SR_BP_SHIFT);
>> > > > > > -		/* Some power-of-two sizes are not supported */
>> > > > > > -		if (val & ~mask)
>> > > > > > -			return -EINVAL;
>> > > > > >  	}
>> > > > > >
>> > > > > > +	/* Some power-of-two sizes are not supported */
>> > > > > > +	if (val & ~mask)
>> > > > > > +		return -EINVAL;
>> > > > > > +
>> > > > > >  	status_new = (status_old & ~mask & ~tb_mask) | val;
>> > > > > >
>> > > > > >  	/* Don't protect status register if we're fully
>> > > > > > unlocked */
>> > > > > > @@ -4736,6 +4824,7 @@ static void
>> > > > > > spi_nor_info_init_params(struct
>> > > > > > spi_nor *nor)
>> > > > > >  	/* Set SPI NOR sizes. */
>> > > > > >  	params->size = (u64)info->sector_size * info-
>> > > > > > > n_sectors;
>> > > > > >
>> > > > > >  	params->page_size = info->page_size;
>> > > > > > +	params->n_sectors = info->n_sectors;
>> > > > > >
>> > > > > >  	if (!(info->flags & SPI_NOR_NO_FR)) {
>> > > > > >  		/* Default to Fast Read for DT and non-DT
>> > > > > > platform
>> > > > > > devices. */
>> > > > > > @@ -5192,6 +5281,11 @@ int spi_nor_scan(struct spi_nor
>> > > > > > *nor,
>> > > > > > const
>> > > > > > char *name,
>> > > > > >  		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
>> > > > > >  	if (info->flags & USE_CLSR)
>> > > > > >  		nor->flags |= SNOR_F_USE_CLSR;
>> > > > > > +	if (info->flags & SPI_NOR_HAS_BP3) {
>> > > > > > +		nor->flags |= SNOR_F_HAS_SR_BP3;
>> > > > > > +		if (info->flags & SPI_NOR_BP3_SR_BIT6)
>> > > > > > +			nor->flags |= SNOR_F_HAS_SR_BP3_BIT6;
>> > > > > > +	}
>> > > > > >
>> > > > > >  	if (info->flags & SPI_NOR_NO_ERASE)
>> > > > > >  		mtd->flags |= MTD_NO_ERASE;
>> > > > > > @@ -5199,6 +5293,7 @@ int spi_nor_scan(struct spi_nor *nor,
>> > > > > > const
>> > > > > > char *name,
>> > > > > >  	mtd->dev.parent = dev;
>> > > > > >  	nor->page_size = params->page_size;
>> > > > > >  	mtd->writebufsize = nor->page_size;
>> > > > > > +	nor->n_sectors = params->n_sectors;
>> > > > > >
>> > > > > >  	if (of_property_read_bool(np, "broken-flash-reset"))
>> > > > > >  		nor->flags |= SNOR_F_BROKEN_RESET;
>> > > > > > diff --git a/include/linux/mtd/spi-nor.h
>> > > > > > b/include/linux/mtd/spi-
>> > > > > > nor.h
>> > > > > > index 541c06d042e8..92d550501daf 100644
>> > > > > > --- a/include/linux/mtd/spi-nor.h
>> > > > > > +++ b/include/linux/mtd/spi-nor.h
>> > > > > > @@ -129,7 +129,9 @@
>> > > > > >  #define SR_BP1			BIT(3)	/* Block
>> > > > > > protect 1
>> > > > > > */
>> > > > > >  #define SR_BP2			BIT(4)	/* Block
>> > > > > > protect 2
>> > > > > > */
>> > > > > >  #define SR_TB_BIT5		BIT(5)	/* Top/Bottom
>> > > > > > protect
>> > > > > > */
>> > > > > > +#define SR_BP3_BIT5		BIT(5)	/* Block
>> > > > > > protect 3
>> > > > > > */
>> > > > >
>> > > > > maybe just name it SR_BP3? would also be more consistent with
>> > > > > the
>> > > > > proposal
>> > > > > above.
>> > > > >
>> > > > > >  #define SR_TB_BIT6		BIT(6)	/* Top/Bottom
>> > > > > > protect
>> > > > > > */
>> > > > > > +#define SR_BP3_BIT6		BIT(6)	/* Block
>> > > > > > protect 3
>> > > > > > */
>> > > > > >  #define SR_SRWD			BIT(7)	/* SR write
>> > > > > > protect
>> > > > > > */
>> > > > > >  /* Spansion/Cypress specific status bits */
>> > > > > >  #define SR_E_ERR		BIT(5)
>> > > > > > @@ -248,6 +250,8 @@ enum spi_nor_option_flags {
>> > > > > >  	SNOR_F_HAS_16BIT_SR	= BIT(9),
>> > > > > >  	SNOR_F_NO_READ_CR	= BIT(10),
>> > > > > >  	SNOR_F_HAS_SR_TB_BIT6	= BIT(11),
>> > > > > > +	SNOR_F_HAS_SR_BP3	= BIT(12),
>> > > > > > +	SNOR_F_HAS_SR_BP3_BIT6	= BIT(13),
>> > > > > >
>> > > > > >  };
>> > > > > >
>> > > > > > @@ -519,6 +523,7 @@ struct spi_nor_locking_ops {
>> > > > > >   *
>> > > > > >   * @size:		the flash memory density in bytes.
>> > > > > >   * @page_size:		the page size of the SPI NOR
>> > > > > > flash
>> > > > > > memory.
>> > > > > > + * @n_sectors:		number of sectors
>> > > > > >   * @hwcaps:		describes the read and page
>> > > > > > program
>> > > > > > hardware
>> > > > > >   *			capabilities.
>> > > > > >   * @reads:		read capabilities ordered by priority:
>> > > > > > the
>> > > > > > higher index
>> > > > > > @@ -541,6 +546,7 @@ struct spi_nor_locking_ops {
>> > > > > >  struct spi_nor_flash_parameter {
>> > > > > >  	u64				size;
>> > > > > >  	u32				page_size;
>> > > > > > +	u16				n_sectors;
>> > > > > >
>> > > > > >  	struct spi_nor_hwcaps		hwcaps;
>> > > > > >  	struct spi_nor_read_command	reads[SNOR_CMD_READ_MAX
>> > > > > > ];
>> > > > > > @@ -573,6 +579,7 @@ struct flash_info;
>> > > > > >   * @bouncebuf_size:	size of the bounce buffer
>> > > > > >   * @info:		spi-nor part JDEC MFR id and other info
>> > > > > >   * @page_size:		the page size of the SPI NOR
>> > > > > > + * @n_sector:		number of sectors
>> > > > > >   * @addr_width:		number of address bytes
>> > > > > >   * @erase_opcode:	the opcode for erasing a sector
>> > > > > >   * @read_opcode:	the read opcode
>> > > > > > @@ -599,6 +606,7 @@ struct spi_nor {
>> > > > > >  	size_t			bouncebuf_size;
>> > > > > >  	const struct flash_info	*info;
>> > > > > >  	u32			page_size;
>> > > > > > +	u16			n_sectors;
>> > > > > >  	u8			addr_width;
>> > > > > >  	u8			erase_opcode;
>> > > > > >  	u8			read_opcode;
>> > > > > > --
>> > > > > > 2.17.1
>> > > > > >
>> > > > > >
>> > > > > > ______________________________________________________
>> > > > > > Linux MTD discussion mailing list
>> > > > > >
>> > > >
>> > > >
>> >
>> >
> https://protect2.fireeye.com/url?k=06b6dd5d-5b7d5a63-06b75612-0cc47a31309a-83164929001f7741&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
>> > > > > >
>> > > > >
>> > > > >
>> > >
>> > >
>> 
>> 

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Hi, Michael

2020-01-28 (화), 13:29 +0100, Michael Walle:
> Am 2020-01-28 12:01, schrieb Jungseung Lee:
> > Hi, Michael
> > 
> > 2020-01-23 (Thu), 10:31 +0100, Michael Walle:
> > > Am 2020-01-23 09:53, schrieb Jungseung Lee:
> > > > Hi, Michael
> > > > 
> > > > 2020-01-23 (Thu), 09:10 +0100, Michael Walle:
> > > > > Hi Jungseung,
> > > > > 
> > > > > Am 2020-01-23 07:22, schrieb Jungseung Lee:
> > > > > > Hi, Michael
> > > > > > 
> > > > > > 2020-01-22 (Wed), 20:36 +0100, Michael Walle:
> > > > > > > Hi,
> > > > > > > 
> > > > > > > > Currently, we are supporting block protection only for
> > > > > > > > flash chips with 3 block protection bits in the SR
> > > > > > > > register.
> > > > > > > > This patch enables block protection support for some
> > > > > > > > flash
> > > > > > > > with
> > > > > > > > 4 block protection bits(bp0-3).
> > > > > > > > 
> > > > > > > > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> > > > > > > > ---
> > > > > > > > v3 :
> > > > > > > >   Fix wrong ofs calculation on v2 patch
> > > > > > > > v2 :
> > > > > > > >   Add sample table portion about 4bit block protection
> > > > > > > > on
> > > > > > > > the
> > > > > > > > comment
> > > > > > > >   Trivial coding style change
> > > > > > > > 
> > > > > > > >  drivers/mtd/spi-nor/spi-nor.c | 127
> > > > > > > > +++++++++++++++++++++++++++++-
> > > > > > > > ----
> > > > > > > >  include/linux/mtd/spi-nor.h   |   8 +++
> > > > > > > >  2 files changed, 119 insertions(+), 16 deletions(-)
> > > > > > > > 
> > > > > > > > diff --git a/drivers/mtd/spi-nor/spi-nor.c
> > > > > > > > b/drivers/mtd/spi-
> > > > > > > > nor/spi-nor.c
> > > > > > > > index e3da6a8654a8..7e8af6c4fdfa 100644
> > > > > > > > --- a/drivers/mtd/spi-nor/spi-nor.c
> > > > > > > > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > > > > > > > @@ -238,6 +238,14 @@ struct flash_info {
> > > > > > > >  					 * status
> > > > > > > > register.
> > > > > > > > Must be
> > > > > > > > used with
> > > > > > > >  					 *
> > > > > > > > SPI_NOR_HAS_TB.
> > > > > > > >  					 */
> > > > > > > > +#define SPI_NOR_HAS_BP3		BIT(17)	/*
> > > > > > > > +					 * Flash SR has
> > > > > > > > 4 bit
> > > > > > > > fields
> > > > > > > > (BP0-3)
> > > > > > > > +					 * for block
> > > > > > > > protection.
> > > > > > > > +					 */
> > > > > > > > +#define SPI_NOR_BP3_SR_BIT6	BIT(18)	/*
> > > > > > > > +					 * BP3 is bit 6
> > > > > > > > of
> > > > > > > > status
> > > > > > > > register.
> > > > > > > > +					 * Must be used
> > > > > > > > with
> > > > > > > > SPI_NOR_HAS_BP3.
> > > > > > > > +					 */
> > > > > > > > 
> > > > > > > >  	/* Part specific fixup hooks. */
> > > > > > > >  	const struct spi_nor_fixups *fixups;
> > > > > > > > @@ -1767,23 +1775,47 @@ static void
> > > > > > > > stm_get_locked_range(struct
> > > > > > > > spi_nor *nor, u8 sr, loff_t *ofs,
> > > > > > > >  	struct mtd_info *mtd = &nor->mtd;
> > > > > > > >  	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
> > > > > > > >  	u8 tb_mask = SR_TB_BIT5;
> > > > > > > > -	int pow;
> > > > > > > > +	u8 bp;
> > > > > > > > +	int pow = 0;
> > > > > > > > 
> > > > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> > > > > > > >  		tb_mask = SR_TB_BIT6;
> > > > > > > > 
> > > > > > > > -	if (!(sr & mask)) {
> > > > > > > > -		/* No protection */
> > > > > > > > -		*ofs = 0;
> > > > > > > > -		*len = 0;
> > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > > > +		u8 tmp;
> > > > > > > > +
> > > > > > > > +		if (nor->flags &
> > > > > > > > SNOR_F_HAS_SR_BP3_BIT6)
> > > > > > > > +			tmp = sr & (mask |
> > > > > > > > SR_BP3_BIT6);
> > > > > > > > +		else
> > > > > > > > +			tmp = sr & (mask |
> > > > > > > > SR_BP3_BIT5);
> > > > > > > > +
> > > > > > > > +		if (tmp & SR_BP3_BIT6)
> > > > > > > > +			tmp = (tmp & ~BIT(6)) | BIT(5);
> > > > > > > > +
> > > > > > > > +		bp = tmp >> SR_BP_SHIFT;
> > > > > > > > +		if (!bp) {
> > > > > > > > +			*ofs = 0;
> > > > > > > > +			*len = 0;
> > > > > > > > +			return;
> > > > > > > > +		}
> > > > > > > > +		if (bp <= ilog2(nor->n_sectors))
> > > > > > > > +			pow = ilog2(nor->n_sectors) + 1
> > > > > > > > - bp;
> > > > > > > >  	} else {
> > > > > > > > -		pow = ((sr & mask) ^ mask) >>
> > > > > > > > SR_BP_SHIFT;
> > > > > > > > -		*len = mtd->size >> pow;
> > > > > > > > -		if (nor->flags & SNOR_F_HAS_SR_TB && sr
> > > > > > > > &
> > > > > > > > tb_mask)
> > > > > > > > +		bp = (sr & mask) >> SR_BP_SHIFT;
> > > > > > > > +		if (!bp) {
> > > > > > > >  			*ofs = 0;
> > > > > > > > -		else
> > > > > > > > -			*ofs = mtd->size - *len;
> > > > > > > > +			*len = 0;
> > > > > > > > +			return;
> > > > > > > > +		}
> > > > > > > > +		pow = bp ^ (mask >> SR_BP_SHIFT);
> > > > > > > >  	}
> > > > > > > > +
> > > > > > > > +	*len = mtd->size >> pow;
> > > > > > > > +
> > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_TB && sr &
> > > > > > > > tb_mask)
> > > > > > > > +		*ofs = 0;
> > > > > > > > +	else
> > > > > > > > +		*ofs = mtd->size - *len;
> > > > > > > >  }
> > > > > > > > 
> > > > > > > >  /*
> > > > > > > > @@ -1823,7 +1855,7 @@ static int
> > > > > > > > stm_is_unlocked_sr(struct
> > > > > > > > spi_nor
> > > > > > > > *nor, loff_t ofs, uint64_t len,
> > > > > > > > 
> > > > > > > >  /*
> > > > > > > >   * Lock a region of the flash. Compatible with ST
> > > > > > > > Micro
> > > > > > > > and
> > > > > > > > similar flash.
> > > > > > > > - * Supports the block protection bits BP{0,1,2} in the
> > > > > > > > status
> > > > > > > > register
> > > > > > > > + * Supports the block protection bits BP{0,1,2,3} in
> > > > > > > > the
> > > > > > > > status
> > > > > > > > register
> > > > > > > >   * (SR). Does not support these features found in
> > > > > > > > newer SR
> > > > > > > > bitfields:
> > > > > > > >   *   - SEC: sector/block protect - only handle SEC=0
> > > > > > > > (block
> > > > > > > > protect)
> > > > > > > >   *   - CMP: complement protect - only support CMP=0
> > > > > > > > (range
> > > > > > > > is
> > > > > > > > not
> > > > > > > > complemented)
> > > > > > > > @@ -1831,7 +1863,7 @@ static int
> > > > > > > > stm_is_unlocked_sr(struct
> > > > > > > > spi_nor
> > > > > > > > *nor, loff_t ofs, uint64_t len,
> > > > > > > >   * Support for the following is provided conditionally
> > > > > > > > for
> > > > > > > > some
> > > > > > > > flash:
> > > > > > > >   *   - TB: top/bottom protect
> > > > > > > >   *
> > > > > > > > - * Sample table portion for 8MB flash (Winbond
> > > > > > > > w25q64fw):
> > > > > > > > + * Sample table portion for 8MB flash (Winbond
> > > > > > > > w25q64fw /
> > > > > > > > BP0-
> > > > > > > > 2):
> > > > > > > >   *
> > > > > > > >   *   SEC  |  TB   |  BP2  |  BP1  |  BP0  |  Prot
> > > > > > > > Length  |
> > > > > > > > Protected Portion
> > > > > > > >   *  ------------------------------------------------
> > > > > > > > ----
> > > > > > > > ----
> > > > > > > > ----
> > > > > > > > --------------
> > > > > > > > @@ -1851,6 +1883,32 @@ static int
> > > > > > > > stm_is_unlocked_sr(struct
> > > > > > > > spi_nor
> > > > > > > > *nor, loff_t ofs, uint64_t len,
> > > > > > > >   *    0   |   1   |   1   |   0   |   1   |  2
> > > > > > > > MB         |
> > > > > > > > Lower
> > > > > > > > 1/4
> > > > > > > >   *    0   |   1   |   1   |   1   |   0   |  4
> > > > > > > > MB         |
> > > > > > > > Lower
> > > > > > > > 1/2
> > > > > > > >   *
> > > > > > > > + * Sample table portion for 64MB flash (Micron
> > > > > > > > n25q512ax3
> > > > > > > > /
> > > > > > > > BP0-
> > > > > > > > 3):
> > > > > > > > + *
> > > > > > > > + *   TB   |  BP3  |  BP2  |  BP1  |  BP0  |  Prot
> > > > > > > > Length  |
> > > > > > > > Protected Portion
> > > > > > > > + *  ------------------------------------------------
> > > > > > > > ----
> > > > > > > > ----
> > > > > > > > ----
> > > > > > > > --------------
> > > > > > > > +
> > > > > > > > *    0   |   0   |   0   |   0   |   0   |  NONE       
> > > > > > > >   |
> > > > > > > > NONE
> > > > > > > > + *    0   |   0   |   0   |   0   |   1   |   64
> > > > > > > > KB       |
> > > > > > > > Upper
> > > > > > > > 1/1024
> > > > > > > > + *    0   |   0   |   0   |   1   |   0   |  128
> > > > > > > > KB       |
> > > > > > > > Upper
> > > > > > > > 1/512
> > > > > > > > + *    0   |   0   |   0   |   1   |   1   |  256
> > > > > > > > KB       |
> > > > > > > > Upper
> > > > > > > > 1/256
> > > > > > > > + *   ...
> > > > > > > > + *    0   |   1   |   0   |   0   |   1   |  16
> > > > > > > > MB        |
> > > > > > > > Upper
> > > > > > > > 1/4
> > > > > > > > + *    0   |   1   |   0   |   1   |   0   |  32
> > > > > > > > MB        |
> > > > > > > > Upper
> > > > > > > > 1/2
> > > > > > > > + *    0   |   1   |   0   |   1   |   1   |  64
> > > > > > > > MB        |
> > > > > > > > ALL
> > > > > > > > + *    0   |   1   |   1   |   0   |   0   |  64
> > > > > > > > MB        |
> > > > > > > > ALL
> > > > > > > > + *   ...
> > > > > > > > + *  ------|-------|-------|-------|-------|-----------
> > > > > > > > ----
> > > > > > > > > ---
> > > > > > > > 
> > > > > > > > ----
> > > > > > > > ------------
> > > > > > > > +
> > > > > > > > *    1   |   0   |   0   |   0   |   0   |   NONE      
> > > > > > > >   |
> > > > > > > > NONE
> > > > > > > > + *    1   |   0   |   0   |   0   |   1   |   64
> > > > > > > > KB       |
> > > > > > > > Lower
> > > > > > > > 1/1024
> > > > > > > > + *    1   |   0   |   0   |   1   |   0   |  128
> > > > > > > > KB       |
> > > > > > > > Lower
> > > > > > > > 1/512
> > > > > > > > + *    1   |   0   |   0   |   1   |   1   |  256
> > > > > > > > KB       |
> > > > > > > > Lower
> > > > > > > > 1/256
> > > > > > > > + *   ...
> > > > > > > > + *    1   |   1   |   0   |   0   |   1   |  16
> > > > > > > > MB        |
> > > > > > > > Lower
> > > > > > > > 1/4
> > > > > > > > + *    1   |   1   |   0   |   1   |   0   |  32
> > > > > > > > MB        |
> > > > > > > > Lower
> > > > > > > > 1/2
> > > > > > > > + *    1   |   1   |   0   |   1   |   1   |  64
> > > > > > > > MB        |
> > > > > > > > ALL
> > > > > > > > + *    1   |   1   |   1   |   0   |   0   |  64
> > > > > > > > MB        |
> > > > > > > > ALL
> > > > > > > > + *   ...
> > > > > > > > + *
> > > > > > > >   * Returns negative on errors, 0 on success.
> > > > > > > >   */
> > > > > > > >  static int stm_lock(struct spi_nor *nor, loff_t ofs,
> > > > > > > > uint64_t
> > > > > > > > len)
> > > > > > > > @@ -1898,6 +1956,12 @@ static int stm_lock(struct
> > > > > > > > spi_nor
> > > > > > > > *nor,
> > > > > > > > loff_t ofs, uint64_t len)
> > > > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> > > > > > > >  		tb_mask = SR_TB_BIT6;
> > > > > > > > 
> > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > > > +		if (nor->flags &
> > > > > > > > SNOR_F_HAS_SR_BP3_BIT6)
> > > > > > > > +			mask = mask | SR_BP3_BIT6;
> > > > > > > > +		else
> > > > > > > > +			mask = mask | SR_BP3_BIT5;
> > > > > > > > +	}
> > > > > > > >  	/*
> > > > > > > >  	 * Need smallest pow such that:
> > > > > > > >  	 *
> > > > > > > > @@ -1908,7 +1972,17 @@ static int stm_lock(struct
> > > > > > > > spi_nor
> > > > > > > > *nor,
> > > > > > > > loff_t ofs, uint64_t len)
> > > > > > > >  	 *   pow = ceil(log2(size / len)) = log2(size)
> > > > > > > > -
> > > > > > > > floor(log2(len))
> > > > > > > >  	 */
> > > > > > > >  	pow = ilog2(mtd->size) - ilog2(lock_len);
> > > > > > > > -	val = mask - (pow << SR_BP_SHIFT);
> > > > > > > > +
> > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
> > > > > > > 
> > > > > > > Why do you use a new calculation here? As far as I can
> > > > > > > see,
> > > > > > > the
> > > > > > > method is
> > > > > > > the same except that is has one bit more. That also
> > > > > > > raises
> > > > > > > the
> > > > > > > question why
> > > > > > > n_sectors is now needed?
> > > > > > > 
> > > > > > > Can't we just initialize the mask with
> > > > > > > 
> > > > > > > mask = SR_BP2 | SR_BP1 | SR_BP0;
> > > > > > > if (nor->flags & SNOR_F_HAS_SR_BP3)
> > > > > > >     mask |= SR_BP3_BIT5;
> > > > > > > 
> > > > > > > do the calculation and checks and then move the
> > > > > > > SR_BP3_BIT5
> > > > > > > to
> > > > > > > SR_BP3_BIT6
> > > > > > > if SNOR_F_HAS_SR_BP3_BIT6 is set.
> > > > > > > 
> > > > > > 
> > > > > > For most of flashes that supporting BP0-2, the smallest
> > > > > > protected
> > > > > > portion is fixed as 1/64
> > > > > > and it can be properly handled by existing
> > > > > > calculation. (Actually it's not fully generic, see flashes
> > > > > > like
> > > > > > w25q40bw or m25p80. Of course, it doesn't have
> > > > > > SPI_NOR_HAS_LOCK
> > > > > > flag
> > > > > > even though it has BP0-2 bit in SR)
> > > > > 
> > > > > No. The rules are always the same wether there are three or
> > > > > four
> > > > > BP
> > > > > bits (the example in stm_lock() has not enough information on
> > > > > this):
> > > > > 
> > > > > (1) the first setting (besides 0) protects one sector. The
> > > > > second
> > > > >      protects 2, the third 4 and so on. eg 2^N
> > > > > (2) the last setting is _always_ protect all, just like the
> > > > > '0'
> > > > > setting
> > > > >      is always protect none.
> > > > > (3) if there is an overflow because there are no more free
> > > > > slots
> > > > > for
> > > > >      further settings (for 3 bits with flashes > 32MBit, for
> > > > > 4
> > > > >      bits if should be flashes > 16GBit), the first entry
> > > > > will be
> > > > >      discarded (eg the very first is the "just one sector"
> > > > > entry).
> > > > > 
> > > > > This is true for all flashes which uses this kind of setting,
> > > > > have a
> > > > > look at the m25p80 or w25q40bw, these are no exception. It is
> > > > > just
> > > > > the
> > > > > notation "lower 1/64" which is only true for flashes which
> > > > > either
> > > > > overflows in (3) or fill all entries (eg. with 3bits that
> > > > > would
> > > > > be
> > > > > the
> > > > > 32Mbit version).
> > > > > 
> > > > 
> > > > Looks like you noticed that we need new calculation method that
> > > > would
> > > > be based on n_sectors :).
> > > 
> > > No it will work without that (if I'm not mistaken). Give me some
> > > time
> > > and I'll post a patch.
> > 
> > No, it must be based on n_sectors. To make 4bit block protection
> > more
> > generic, the lock sector size must NOT fixed as 64KB (as can be
> > checked
> > from your patch). See "mt35xu02g" and check the protected area and
> > number of sectors from it's datasheet.
> 
> There is no public datasheet as far as I can see. And yes, actually
> n_sectors is my "mtd-size / sector_size". But I don't see how
> n_sectors
> would help if the sector size changes.
> 
> > The rule you mentioned "the first setting (besides 0) protects one
> > sector" is alawys true for *4bit* block protection. That's why I
> > choose
> > n_sectors for new calculation.
> 
> And how does flashes behave once all the free slots are full? It was
> the
> same with the 3bit flashes, they only overflowed with "newer"/bigger
> flashes.
> 
> 
> > > 
> > > > Rule (1) is NOT true for some flashes
> > > > supporting BP0-2 and that's why I said that smallest protected
> > > > portion
> > > > is fixed as '1/64' for these flashes.
> > > 
> > > No, you have to apply rule (3). (1) is only the starting point.
> > > It
> > > is
> > > kind
> > > of a sliding window.
> > > 
> > > > See this one.
> > > > 
> > > > W25Q20EW	256KB	1/4 ... = 64KB		BP2
> > > > W25Q128JV	16MB	1/64 ... = 256KB	BP2 <--
> > > > S25FL132K	4MB	1/64 ... = 64KB		BP2 <--
> > > > S25FL164K	8MB
> > > > 1/64 ... = 128KB	BP2 <--
> > > 
> > > All these flashes need (3) to be applied, thus (1) doesn't apply
> > > anymore.
> > > 
> > > Let me give you an example for the 64MBit case, the settings
> > > would
> > > be:
> > > 
> > > 0 sectors (corresponds to protect none)
> > > 1 sector
> > > 2 sectors
> > > 4 sectors
> > > 8 sectors
> > > 16 sectors
> > > 32 sectors
> > > 64 sectors
> > > 128 sectors (corresponds to protect all)
> > > 
> > > Unfortunately, we have only 8 slots (because 3 BP bits),
> > > therefore
> > > we
> > > have
> > > to discard some setting. According to rule (2) 0 is always
> > > "protect
> > > none"
> > > and 7 is always "protect all". Thus we have 6 settings left.
> > > According
> > > to
> > > rule (3) we discard the first ones. In this case, this is the "1
> > > sector"
> > > setting. Thus we end up with the following possible settings:
> > > 
> > > 0 sectors (corresponds to protect none)
> > > 2 sectors
> > > 4 sectors
> > > 8 sectors
> > > 16 sectors
> > > 32 sectors
> > > 64 sectors
> > > 128 sectors (corresponds to protect all)
> > > 
> > > If you have a 128Mbit flash, the next setting that would be
> > > discarded
> > > is
> > > "2 sectors". Thus it would start with:
> > > 
> > > 0 sectors (corresponds to protect none)
> > > 4 sectors
> > > [..]
> > > 256 sectors (corresponds to protect all)
> > > 
> > > 
> > > Another example W25Q20EW, following possible settings:
> > > 
> > > 0 sectors (corresponds to protect none)
> > > 1 sector
> > > 2 sectors
> > > 4 sectors (corresponds to protect all)
> > > 
> > > We now have less settings then our 8 possible slots. So this is
> > > where
> > > rule (1) applies, because according to that the "1 sector"
> > > setting is
> > > the first possible setting besides 0.
> > > 
> > > And this also applies to the 4 bit protection bits.
> > > 
> > > 
> > > 
> > > > W25Q256JV	32MB	1/512 ... =
> > > > 64KB	BP3
> > > > S25FL128L	16MB	1/256 ... = 64KB	BP3
> > > > S25FL256L	32MB	1/512 ... = 64KB	BP3
> > > > 
> > > > In current BP implementation, block protection is just working
> > > > for
> > > > some
> > > > flashes that has smallest protected portion as '1/64'.
> > > 
> > > No its currently working for all except flashes smaller than
> > > 32Mbit.
> > 
> > No. Not working for flashes supporting 4bit block protection.
> > 
> > > Applied to the 4 bits, this would mean "it works for all except
> > > flashes
> > > smaller than 8Gbit" which are practially all. As I said, this is
> > > a
> > > bug
> > > and once this bug is fixed, there should be no difference between
> > > 3
> > > and 4 bits.
> > > 
> > > -michael
> > > 
> > 
> > The exact fact is that locks operate in two different ways
> > according to
> > flash model.
> > 
> > (1) the smallest protected portion is fixed.
> > 	for BP0-2 : 1/64
> > 	for BP0-1 : 1/4
> 
> As mentioned earlier, the ratio nomenclature is missleading and only 
> valid if the table is completely filled up.
> 
> Take a flash with 128kB and three BP bits (or even only two BP
> bits). 
> The
> smallest portion will be 64kB (which is one sector and not 1/64).
> 
> Thus the smallest portion is always one sector, unless the table is
> overflowing, then the smallest will settle to 1/4 (for two), 1/64
> (for 
> three)
> and 1/16384 (for four bits).
> 
> > (2) the smallest protected portion is inversely propotional with
> > number
> > of sectors.
> > 
> > For the flashes supporting 3bit block protection, (1) and (2) are
> > mixed
> > and used. But all the flashes supporting 4bit block protection
> > listed
> > on spi-nor.c, only (2) is used.
> 
> It is not mixed it just depends on the flash size (and the number of
> protection bits).
> 

It is mixed. Let's compare "en25qh128" from EON with "w25q128jv" from
Winbond. They have the same capacity(128MBit) and also supporting 3bit
block protection. (Note that the named BP3 bit of "en25qh128" is
working exactly same with T/B bit.)

"en25qh128" is following (2) and "w25q128jv" is following (1). It seems
impossible to distinguish them by the flash size or the number of
protection bits. 

I also still have no idea how your three rules are applicable for 2bit
block protection (bp0-1).

> > Each method requires each formula. I have no idea how to handle it
> > with
> > one formula (probably adding number of exceptional handling?)
> > without
> > any sectional flag. "w25q128jv(bp0-2)" is following (1) and
> > "n25q128a(bp0-3)" is following (2).
> 
> Well one uses three BPs the other four, and they all follow the
> three 
> rules
> above. Did you try my patch? Because I've (at least in userspace)
> tested
> it with 4 bits and got the correct results.
> 
> And yes, its actually two different formulas, but not for 3 and 4
> bits like in your patch. 

The title of my patch is "add 4bit block protection support". I just
let 3bit block protection as it is, I've implemented something what I
could check. As I mentioned, for all the flashes supporting 4bit block
protection only (2) is used and this patch has been implemented based
on this fact.

> It is rather one formula (A) for flashes which don't 
> exhaust
> the BP bits (eg. for 3 bits this would be flashes <= 16Mbit and for
> 4 
> bits
> this would be for flashes <=8Gbit) and one (B) for the flashes where 
> every
> BP bit combination is used. What is at the moment in the kernel is
> the
> second one, thus it will fail for flashes <= 16Mbit and 3 BP bits;
> and 
> it
> also fails for all flashes with 4 bits. My patch does a fixup on (B)
> to
> match the results of (A), because doing this is less invasive; and as
> mentioned in the patch annex, might also be rewritten for a better
> understanding.

I've never seen spi flashes greater than 8Gbit (maybe you also), so I
am not sure whether the three rules are applicable to 4 bit block
protection. Even the three rules doesn't seem to be general enough for
3bit or 2bit block protection.

> 
> 
> -michael
> 
> > 
> > > > 
> > > > We need new fomula based on n_sectors for BP3 at least.
> > > 
> > > No they are the same, but yes there is a bug in the current
> > > implementation.
> > > 
> > > -michael
> > > 
> > > > 
> > > > > So for the 3 bit case the following flashes are border cases:
> > > > >   - 16mbit (less settings than slots)
> > > > >   - 32mbit (number of settings and free slots match)
> > > > >   - 64mbit (more settings than slots, first setting is
> > > > > discarded)
> > > > > 
> > > > > That being said, I suspect all the 16mbit flashes (and below)
> > > > > which
> > > > > have
> > > > > the _LOCK bit set are broken, because the entries has to be
> > > > > shifted.
> > > > > I'll
> > > > > look into that later. This is the same "issue" you have with
> > > > > the
> > > > > 4
> > > > > bits.
> > > > > So if this is fixed, you should not need another formula for
> > > > > the
> > > > > 4
> > > > > bit
> > > > > case.
> > > > > 
> > > > > > We need new calculation method for 4bit block protection
> > > > > > and
> > > > > > for
> > > > > > making
> > > > > > it more generic, I choose n_sectors.
> > > > > > 
> > > > > > On all the flashes I checked, n_sectors is proper value for
> > > > > > getting
> > > > > > block protected portion.
> > > > > > 
> > > > > > 		density	portion	n_sectors
> > > > > > W25M512JV	64MB	1/512	512
> > > > > > N25Q128A	16MB	1/256	256
> > > > > > N25Q512A	64MB	1/1024	1024
> > > > > > MT25QL02GCBB	256MB	1/4096	4096
> > > > > 
> > > > > The rules above apply to these flashes, too. Could you double
> > > > > check
> > > > > that?
> > > > > 
> > > > > -michael
> > > > > 
> > > > > > 
> > > > > > > > +		val = val << SR_BP_SHIFT;
> > > > > > > > +
> > > > > > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
> > > > > > > > +			val = (val & ~BIT(5)) | BIT(6);
> > > > > > > > +	} else {
> > > > > > > > +		val = mask - (pow << SR_BP_SHIFT);
> > > > > > > > +	}
> > > > > > > > +
> > > > > > > >  	if (val & ~mask)
> > > > > > > >  		return -EINVAL;
> > > > > > > >  	/* Don't "lock" with no region! */
> > > > > > > > @@ -1983,6 +2057,13 @@ static int stm_unlock(struct
> > > > > > > > spi_nor
> > > > > > > > *nor,
> > > > > > > > loff_t ofs, uint64_t len)
> > > > > > > > 
> > > > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> > > > > > > >  		tb_mask = SR_TB_BIT6;
> > > > > > > > +
> > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > > > +		if (nor->flags &
> > > > > > > > SNOR_F_HAS_SR_BP3_BIT6)
> > > > > > > > +			mask = mask | SR_BP3_BIT6;
> > > > > > > > +		else
> > > > > > > > +			mask = mask | SR_BP3_BIT5;
> > > > > > > > +	}
> > > > > > > >  	/*
> > > > > > > >  	 * Need largest pow such that:
> > > > > > > >  	 *
> > > > > > > > @@ -1995,13 +2076,20 @@ static int stm_unlock(struct
> > > > > > > > spi_nor
> > > > > > > > *nor,
> > > > > > > > loff_t ofs, uint64_t len)
> > > > > > > >  	pow = ilog2(mtd->size) -
> > > > > > > > order_base_2(lock_len);
> > > > > > > >  	if (lock_len == 0) {
> > > > > > > >  		val = 0; /* fully unlocked */
> > > > > > > > +	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
> > > > > > > > +		val = val << SR_BP_SHIFT;
> > > > > > > > +
> > > > > > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
> > > > > > > > +			val = (val & ~BIT(5)) | BIT(6);
> > > > > > > >  	} else {
> > > > > > > >  		val = mask - (pow << SR_BP_SHIFT);
> > > > > > > > -		/* Some power-of-two sizes are not
> > > > > > > > supported */
> > > > > > > > -		if (val & ~mask)
> > > > > > > > -			return -EINVAL;
> > > > > > > >  	}
> > > > > > > > 
> > > > > > > > +	/* Some power-of-two sizes are not supported */
> > > > > > > > +	if (val & ~mask)
> > > > > > > > +		return -EINVAL;
> > > > > > > > +
> > > > > > > >  	status_new = (status_old & ~mask & ~tb_mask) |
> > > > > > > > val;
> > > > > > > > 
> > > > > > > >  	/* Don't protect status register if we're fully
> > > > > > > > unlocked */
> > > > > > > > @@ -4736,6 +4824,7 @@ static void
> > > > > > > > spi_nor_info_init_params(struct
> > > > > > > > spi_nor *nor)
> > > > > > > >  	/* Set SPI NOR sizes. */
> > > > > > > >  	params->size = (u64)info->sector_size * info-
> > > > > > > > > n_sectors;
> > > > > > > > 
> > > > > > > >  	params->page_size = info->page_size;
> > > > > > > > +	params->n_sectors = info->n_sectors;
> > > > > > > > 
> > > > > > > >  	if (!(info->flags & SPI_NOR_NO_FR)) {
> > > > > > > >  		/* Default to Fast Read for DT and non-
> > > > > > > > DT
> > > > > > > > platform
> > > > > > > > devices. */
> > > > > > > > @@ -5192,6 +5281,11 @@ int spi_nor_scan(struct spi_nor
> > > > > > > > *nor,
> > > > > > > > const
> > > > > > > > char *name,
> > > > > > > >  		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
> > > > > > > >  	if (info->flags & USE_CLSR)
> > > > > > > >  		nor->flags |= SNOR_F_USE_CLSR;
> > > > > > > > +	if (info->flags & SPI_NOR_HAS_BP3) {
> > > > > > > > +		nor->flags |= SNOR_F_HAS_SR_BP3;
> > > > > > > > +		if (info->flags & SPI_NOR_BP3_SR_BIT6)
> > > > > > > > +			nor->flags |=
> > > > > > > > SNOR_F_HAS_SR_BP3_BIT6;
> > > > > > > > +	}
> > > > > > > > 
> > > > > > > >  	if (info->flags & SPI_NOR_NO_ERASE)
> > > > > > > >  		mtd->flags |= MTD_NO_ERASE;
> > > > > > > > @@ -5199,6 +5293,7 @@ int spi_nor_scan(struct spi_nor
> > > > > > > > *nor,
> > > > > > > > const
> > > > > > > > char *name,
> > > > > > > >  	mtd->dev.parent = dev;
> > > > > > > >  	nor->page_size = params->page_size;
> > > > > > > >  	mtd->writebufsize = nor->page_size;
> > > > > > > > +	nor->n_sectors = params->n_sectors;
> > > > > > > > 
> > > > > > > >  	if (of_property_read_bool(np, "broken-flash-
> > > > > > > > reset"))
> > > > > > > >  		nor->flags |= SNOR_F_BROKEN_RESET;
> > > > > > > > diff --git a/include/linux/mtd/spi-nor.h
> > > > > > > > b/include/linux/mtd/spi-
> > > > > > > > nor.h
> > > > > > > > index 541c06d042e8..92d550501daf 100644
> > > > > > > > --- a/include/linux/mtd/spi-nor.h
> > > > > > > > +++ b/include/linux/mtd/spi-nor.h
> > > > > > > > @@ -129,7 +129,9 @@
> > > > > > > >  #define SR_BP1			BIT(3)	/* Block
> > > > > > > > protect 1
> > > > > > > > */
> > > > > > > >  #define SR_BP2			BIT(4)	/* Block
> > > > > > > > protect 2
> > > > > > > > */
> > > > > > > >  #define SR_TB_BIT5		BIT(5)	/* Top/Bottom
> > > > > > > > protect
> > > > > > > > */
> > > > > > > > +#define SR_BP3_BIT5		BIT(5)	/* Block
> > > > > > > > protect 3
> > > > > > > > */
> > > > > > > 
> > > > > > > maybe just name it SR_BP3? would also be more consistent
> > > > > > > with
> > > > > > > the
> > > > > > > proposal
> > > > > > > above.
> > > > > > > 
> > > > > > > >  #define SR_TB_BIT6		BIT(6)	/* Top/Bottom
> > > > > > > > protect
> > > > > > > > */
> > > > > > > > +#define SR_BP3_BIT6		BIT(6)	/* Block
> > > > > > > > protect 3
> > > > > > > > */
> > > > > > > >  #define SR_SRWD			BIT(7)	/* SR
> > > > > > > > write
> > > > > > > > protect
> > > > > > > > */
> > > > > > > >  /* Spansion/Cypress specific status bits */
> > > > > > > >  #define SR_E_ERR		BIT(5)
> > > > > > > > @@ -248,6 +250,8 @@ enum spi_nor_option_flags {
> > > > > > > >  	SNOR_F_HAS_16BIT_SR	= BIT(9),
> > > > > > > >  	SNOR_F_NO_READ_CR	= BIT(10),
> > > > > > > >  	SNOR_F_HAS_SR_TB_BIT6	= BIT(11),
> > > > > > > > +	SNOR_F_HAS_SR_BP3	= BIT(12),
> > > > > > > > +	SNOR_F_HAS_SR_BP3_BIT6	= BIT(13),
> > > > > > > > 
> > > > > > > >  };
> > > > > > > > 
> > > > > > > > @@ -519,6 +523,7 @@ struct spi_nor_locking_ops {
> > > > > > > >   *
> > > > > > > >   * @size:		the flash memory density in
> > > > > > > > bytes.
> > > > > > > >   * @page_size:		the page size of the SPI NOR
> > > > > > > > flash
> > > > > > > > memory.
> > > > > > > > + * @n_sectors:		number of sectors
> > > > > > > >   * @hwcaps:		describes the read and page
> > > > > > > > program
> > > > > > > > hardware
> > > > > > > >   *			capabilities.
> > > > > > > >   * @reads:		read capabilities ordered by
> > > > > > > > priority:
> > > > > > > > the
> > > > > > > > higher index
> > > > > > > > @@ -541,6 +546,7 @@ struct spi_nor_locking_ops {
> > > > > > > >  struct spi_nor_flash_parameter {
> > > > > > > >  	u64				size;
> > > > > > > >  	u32				page_size;
> > > > > > > > +	u16				n_sectors;
> > > > > > > > 
> > > > > > > >  	struct spi_nor_hwcaps		hwcaps;
> > > > > > > >  	struct spi_nor_read_command	reads[SNOR_CMD_
> > > > > > > > READ_MAX
> > > > > > > > ];
> > > > > > > > @@ -573,6 +579,7 @@ struct flash_info;
> > > > > > > >   * @bouncebuf_size:	size of the bounce buffer
> > > > > > > >   * @info:		spi-nor part JDEC MFR id and
> > > > > > > > other info
> > > > > > > >   * @page_size:		the page size of the SPI NOR
> > > > > > > > + * @n_sector:		number of sectors
> > > > > > > >   * @addr_width:		number of address bytes
> > > > > > > >   * @erase_opcode:	the opcode for erasing a sector
> > > > > > > >   * @read_opcode:	the read opcode
> > > > > > > > @@ -599,6 +606,7 @@ struct spi_nor {
> > > > > > > >  	size_t			bouncebuf_size;
> > > > > > > >  	const struct flash_info	*info;
> > > > > > > >  	u32			page_size;
> > > > > > > > +	u16			n_sectors;
> > > > > > > >  	u8			addr_width;
> > > > > > > >  	u8			erase_opcode;
> > > > > > > >  	u8			read_opcode;
> > > > > > > > --
> > > > > > > > 2.17.1
> > > > > > > > 
> > > > > > > > 
> > > > > > > > ______________________________________________________
> > > > > > > > Linux MTD discussion mailing list
> > > > > > > > 
> > > > > > 
> > > > > > 
> > > > 
> > > > 
> > 
> > 
https://protect2.fireeye.com/url?k=06b6dd5d-5b7d5a63-06b75612-0cc47a31309a-83164929001f7741&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
> > > > > > > > 
> > > > > > > 
> > > > > > > 
> > > > > 
> > > > > 
> > > 
> > > 
> 
> 

Thanks,
Jungseung Lee


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[SPAM] Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Hi Jungseung,

Am 2020-01-30 09:17, schrieb Jungseung Lee:
> Hi, Michael
> 
> 2020-01-28 (화), 13:29 +0100, Michael Walle:
>> Am 2020-01-28 12:01, schrieb Jungseung Lee:
>> > Hi, Michael
>> >
>> > 2020-01-23 (Thu), 10:31 +0100, Michael Walle:
>> > > Am 2020-01-23 09:53, schrieb Jungseung Lee:
>> > > > Hi, Michael
>> > > >
>> > > > 2020-01-23 (Thu), 09:10 +0100, Michael Walle:
>> > > > > Hi Jungseung,
>> > > > >
>> > > > > Am 2020-01-23 07:22, schrieb Jungseung Lee:
>> > > > > > Hi, Michael
>> > > > > >
>> > > > > > 2020-01-22 (Wed), 20:36 +0100, Michael Walle:
>> > > > > > > Hi,
>> > > > > > >
>> > > > > > > > Currently, we are supporting block protection only for
>> > > > > > > > flash chips with 3 block protection bits in the SR
>> > > > > > > > register.
>> > > > > > > > This patch enables block protection support for some
>> > > > > > > > flash
>> > > > > > > > with
>> > > > > > > > 4 block protection bits(bp0-3).
>> > > > > > > >
>> > > > > > > > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
>> > > > > > > > ---
>> > > > > > > > v3 :
>> > > > > > > >   Fix wrong ofs calculation on v2 patch
>> > > > > > > > v2 :
>> > > > > > > >   Add sample table portion about 4bit block protection
>> > > > > > > > on
>> > > > > > > > the
>> > > > > > > > comment
>> > > > > > > >   Trivial coding style change
>> > > > > > > >
>> > > > > > > >  drivers/mtd/spi-nor/spi-nor.c | 127
>> > > > > > > > +++++++++++++++++++++++++++++-
>> > > > > > > > ----
>> > > > > > > >  include/linux/mtd/spi-nor.h   |   8 +++
>> > > > > > > >  2 files changed, 119 insertions(+), 16 deletions(-)
>> > > > > > > >
>> > > > > > > > diff --git a/drivers/mtd/spi-nor/spi-nor.c
>> > > > > > > > b/drivers/mtd/spi-
>> > > > > > > > nor/spi-nor.c
>> > > > > > > > index e3da6a8654a8..7e8af6c4fdfa 100644
>> > > > > > > > --- a/drivers/mtd/spi-nor/spi-nor.c
>> > > > > > > > +++ b/drivers/mtd/spi-nor/spi-nor.c
>> > > > > > > > @@ -238,6 +238,14 @@ struct flash_info {
>> > > > > > > >  					 * status
>> > > > > > > > register.
>> > > > > > > > Must be
>> > > > > > > > used with
>> > > > > > > >  					 *
>> > > > > > > > SPI_NOR_HAS_TB.
>> > > > > > > >  					 */
>> > > > > > > > +#define SPI_NOR_HAS_BP3		BIT(17)	/*
>> > > > > > > > +					 * Flash SR has
>> > > > > > > > 4 bit
>> > > > > > > > fields
>> > > > > > > > (BP0-3)
>> > > > > > > > +					 * for block
>> > > > > > > > protection.
>> > > > > > > > +					 */
>> > > > > > > > +#define SPI_NOR_BP3_SR_BIT6	BIT(18)	/*
>> > > > > > > > +					 * BP3 is bit 6
>> > > > > > > > of
>> > > > > > > > status
>> > > > > > > > register.
>> > > > > > > > +					 * Must be used
>> > > > > > > > with
>> > > > > > > > SPI_NOR_HAS_BP3.
>> > > > > > > > +					 */
>> > > > > > > >
>> > > > > > > >  	/* Part specific fixup hooks. */
>> > > > > > > >  	const struct spi_nor_fixups *fixups;
>> > > > > > > > @@ -1767,23 +1775,47 @@ static void
>> > > > > > > > stm_get_locked_range(struct
>> > > > > > > > spi_nor *nor, u8 sr, loff_t *ofs,
>> > > > > > > >  	struct mtd_info *mtd = &nor->mtd;
>> > > > > > > >  	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
>> > > > > > > >  	u8 tb_mask = SR_TB_BIT5;
>> > > > > > > > -	int pow;
>> > > > > > > > +	u8 bp;
>> > > > > > > > +	int pow = 0;
>> > > > > > > >
>> > > > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>> > > > > > > >  		tb_mask = SR_TB_BIT6;
>> > > > > > > >
>> > > > > > > > -	if (!(sr & mask)) {
>> > > > > > > > -		/* No protection */
>> > > > > > > > -		*ofs = 0;
>> > > > > > > > -		*len = 0;
>> > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > > > > > +		u8 tmp;
>> > > > > > > > +
>> > > > > > > > +		if (nor->flags &
>> > > > > > > > SNOR_F_HAS_SR_BP3_BIT6)
>> > > > > > > > +			tmp = sr & (mask |
>> > > > > > > > SR_BP3_BIT6);
>> > > > > > > > +		else
>> > > > > > > > +			tmp = sr & (mask |
>> > > > > > > > SR_BP3_BIT5);
>> > > > > > > > +
>> > > > > > > > +		if (tmp & SR_BP3_BIT6)
>> > > > > > > > +			tmp = (tmp & ~BIT(6)) | BIT(5);
>> > > > > > > > +
>> > > > > > > > +		bp = tmp >> SR_BP_SHIFT;
>> > > > > > > > +		if (!bp) {
>> > > > > > > > +			*ofs = 0;
>> > > > > > > > +			*len = 0;
>> > > > > > > > +			return;
>> > > > > > > > +		}
>> > > > > > > > +		if (bp <= ilog2(nor->n_sectors))
>> > > > > > > > +			pow = ilog2(nor->n_sectors) + 1
>> > > > > > > > - bp;
>> > > > > > > >  	} else {
>> > > > > > > > -		pow = ((sr & mask) ^ mask) >>
>> > > > > > > > SR_BP_SHIFT;
>> > > > > > > > -		*len = mtd->size >> pow;
>> > > > > > > > -		if (nor->flags & SNOR_F_HAS_SR_TB && sr
>> > > > > > > > &
>> > > > > > > > tb_mask)
>> > > > > > > > +		bp = (sr & mask) >> SR_BP_SHIFT;
>> > > > > > > > +		if (!bp) {
>> > > > > > > >  			*ofs = 0;
>> > > > > > > > -		else
>> > > > > > > > -			*ofs = mtd->size - *len;
>> > > > > > > > +			*len = 0;
>> > > > > > > > +			return;
>> > > > > > > > +		}
>> > > > > > > > +		pow = bp ^ (mask >> SR_BP_SHIFT);
>> > > > > > > >  	}
>> > > > > > > > +
>> > > > > > > > +	*len = mtd->size >> pow;
>> > > > > > > > +
>> > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_TB && sr &
>> > > > > > > > tb_mask)
>> > > > > > > > +		*ofs = 0;
>> > > > > > > > +	else
>> > > > > > > > +		*ofs = mtd->size - *len;
>> > > > > > > >  }
>> > > > > > > >
>> > > > > > > >  /*
>> > > > > > > > @@ -1823,7 +1855,7 @@ static int
>> > > > > > > > stm_is_unlocked_sr(struct
>> > > > > > > > spi_nor
>> > > > > > > > *nor, loff_t ofs, uint64_t len,
>> > > > > > > >
>> > > > > > > >  /*
>> > > > > > > >   * Lock a region of the flash. Compatible with ST
>> > > > > > > > Micro
>> > > > > > > > and
>> > > > > > > > similar flash.
>> > > > > > > > - * Supports the block protection bits BP{0,1,2} in the
>> > > > > > > > status
>> > > > > > > > register
>> > > > > > > > + * Supports the block protection bits BP{0,1,2,3} in
>> > > > > > > > the
>> > > > > > > > status
>> > > > > > > > register
>> > > > > > > >   * (SR). Does not support these features found in
>> > > > > > > > newer SR
>> > > > > > > > bitfields:
>> > > > > > > >   *   - SEC: sector/block protect - only handle SEC=0
>> > > > > > > > (block
>> > > > > > > > protect)
>> > > > > > > >   *   - CMP: complement protect - only support CMP=0
>> > > > > > > > (range
>> > > > > > > > is
>> > > > > > > > not
>> > > > > > > > complemented)
>> > > > > > > > @@ -1831,7 +1863,7 @@ static int
>> > > > > > > > stm_is_unlocked_sr(struct
>> > > > > > > > spi_nor
>> > > > > > > > *nor, loff_t ofs, uint64_t len,
>> > > > > > > >   * Support for the following is provided conditionally
>> > > > > > > > for
>> > > > > > > > some
>> > > > > > > > flash:
>> > > > > > > >   *   - TB: top/bottom protect
>> > > > > > > >   *
>> > > > > > > > - * Sample table portion for 8MB flash (Winbond
>> > > > > > > > w25q64fw):
>> > > > > > > > + * Sample table portion for 8MB flash (Winbond
>> > > > > > > > w25q64fw /
>> > > > > > > > BP0-
>> > > > > > > > 2):
>> > > > > > > >   *
>> > > > > > > >   *   SEC  |  TB   |  BP2  |  BP1  |  BP0  |  Prot
>> > > > > > > > Length  |
>> > > > > > > > Protected Portion
>> > > > > > > >   *  ------------------------------------------------
>> > > > > > > > ----
>> > > > > > > > ----
>> > > > > > > > ----
>> > > > > > > > --------------
>> > > > > > > > @@ -1851,6 +1883,32 @@ static int
>> > > > > > > > stm_is_unlocked_sr(struct
>> > > > > > > > spi_nor
>> > > > > > > > *nor, loff_t ofs, uint64_t len,
>> > > > > > > >   *    0   |   1   |   1   |   0   |   1   |  2
>> > > > > > > > MB         |
>> > > > > > > > Lower
>> > > > > > > > 1/4
>> > > > > > > >   *    0   |   1   |   1   |   1   |   0   |  4
>> > > > > > > > MB         |
>> > > > > > > > Lower
>> > > > > > > > 1/2
>> > > > > > > >   *
>> > > > > > > > + * Sample table portion for 64MB flash (Micron
>> > > > > > > > n25q512ax3
>> > > > > > > > /
>> > > > > > > > BP0-
>> > > > > > > > 3):
>> > > > > > > > + *
>> > > > > > > > + *   TB   |  BP3  |  BP2  |  BP1  |  BP0  |  Prot
>> > > > > > > > Length  |
>> > > > > > > > Protected Portion
>> > > > > > > > + *  ------------------------------------------------
>> > > > > > > > ----
>> > > > > > > > ----
>> > > > > > > > ----
>> > > > > > > > --------------
>> > > > > > > > +
>> > > > > > > > *    0   |   0   |   0   |   0   |   0   |  NONE
>> > > > > > > >   |
>> > > > > > > > NONE
>> > > > > > > > + *    0   |   0   |   0   |   0   |   1   |   64
>> > > > > > > > KB       |
>> > > > > > > > Upper
>> > > > > > > > 1/1024
>> > > > > > > > + *    0   |   0   |   0   |   1   |   0   |  128
>> > > > > > > > KB       |
>> > > > > > > > Upper
>> > > > > > > > 1/512
>> > > > > > > > + *    0   |   0   |   0   |   1   |   1   |  256
>> > > > > > > > KB       |
>> > > > > > > > Upper
>> > > > > > > > 1/256
>> > > > > > > > + *   ...
>> > > > > > > > + *    0   |   1   |   0   |   0   |   1   |  16
>> > > > > > > > MB        |
>> > > > > > > > Upper
>> > > > > > > > 1/4
>> > > > > > > > + *    0   |   1   |   0   |   1   |   0   |  32
>> > > > > > > > MB        |
>> > > > > > > > Upper
>> > > > > > > > 1/2
>> > > > > > > > + *    0   |   1   |   0   |   1   |   1   |  64
>> > > > > > > > MB        |
>> > > > > > > > ALL
>> > > > > > > > + *    0   |   1   |   1   |   0   |   0   |  64
>> > > > > > > > MB        |
>> > > > > > > > ALL
>> > > > > > > > + *   ...
>> > > > > > > > + *  ------|-------|-------|-------|-------|-----------
>> > > > > > > > ----
>> > > > > > > > > ---
>> > > > > > > >
>> > > > > > > > ----
>> > > > > > > > ------------
>> > > > > > > > +
>> > > > > > > > *    1   |   0   |   0   |   0   |   0   |   NONE
>> > > > > > > >   |
>> > > > > > > > NONE
>> > > > > > > > + *    1   |   0   |   0   |   0   |   1   |   64
>> > > > > > > > KB       |
>> > > > > > > > Lower
>> > > > > > > > 1/1024
>> > > > > > > > + *    1   |   0   |   0   |   1   |   0   |  128
>> > > > > > > > KB       |
>> > > > > > > > Lower
>> > > > > > > > 1/512
>> > > > > > > > + *    1   |   0   |   0   |   1   |   1   |  256
>> > > > > > > > KB       |
>> > > > > > > > Lower
>> > > > > > > > 1/256
>> > > > > > > > + *   ...
>> > > > > > > > + *    1   |   1   |   0   |   0   |   1   |  16
>> > > > > > > > MB        |
>> > > > > > > > Lower
>> > > > > > > > 1/4
>> > > > > > > > + *    1   |   1   |   0   |   1   |   0   |  32
>> > > > > > > > MB        |
>> > > > > > > > Lower
>> > > > > > > > 1/2
>> > > > > > > > + *    1   |   1   |   0   |   1   |   1   |  64
>> > > > > > > > MB        |
>> > > > > > > > ALL
>> > > > > > > > + *    1   |   1   |   1   |   0   |   0   |  64
>> > > > > > > > MB        |
>> > > > > > > > ALL
>> > > > > > > > + *   ...
>> > > > > > > > + *
>> > > > > > > >   * Returns negative on errors, 0 on success.
>> > > > > > > >   */
>> > > > > > > >  static int stm_lock(struct spi_nor *nor, loff_t ofs,
>> > > > > > > > uint64_t
>> > > > > > > > len)
>> > > > > > > > @@ -1898,6 +1956,12 @@ static int stm_lock(struct
>> > > > > > > > spi_nor
>> > > > > > > > *nor,
>> > > > > > > > loff_t ofs, uint64_t len)
>> > > > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>> > > > > > > >  		tb_mask = SR_TB_BIT6;
>> > > > > > > >
>> > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > > > > > +		if (nor->flags &
>> > > > > > > > SNOR_F_HAS_SR_BP3_BIT6)
>> > > > > > > > +			mask = mask | SR_BP3_BIT6;
>> > > > > > > > +		else
>> > > > > > > > +			mask = mask | SR_BP3_BIT5;
>> > > > > > > > +	}
>> > > > > > > >  	/*
>> > > > > > > >  	 * Need smallest pow such that:
>> > > > > > > >  	 *
>> > > > > > > > @@ -1908,7 +1972,17 @@ static int stm_lock(struct
>> > > > > > > > spi_nor
>> > > > > > > > *nor,
>> > > > > > > > loff_t ofs, uint64_t len)
>> > > > > > > >  	 *   pow = ceil(log2(size / len)) = log2(size)
>> > > > > > > > -
>> > > > > > > > floor(log2(len))
>> > > > > > > >  	 */
>> > > > > > > >  	pow = ilog2(mtd->size) - ilog2(lock_len);
>> > > > > > > > -	val = mask - (pow << SR_BP_SHIFT);
>> > > > > > > > +
>> > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > > > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
>> > > > > > >
>> > > > > > > Why do you use a new calculation here? As far as I can
>> > > > > > > see,
>> > > > > > > the
>> > > > > > > method is
>> > > > > > > the same except that is has one bit more. That also
>> > > > > > > raises
>> > > > > > > the
>> > > > > > > question why
>> > > > > > > n_sectors is now needed?
>> > > > > > >
>> > > > > > > Can't we just initialize the mask with
>> > > > > > >
>> > > > > > > mask = SR_BP2 | SR_BP1 | SR_BP0;
>> > > > > > > if (nor->flags & SNOR_F_HAS_SR_BP3)
>> > > > > > >     mask |= SR_BP3_BIT5;
>> > > > > > >
>> > > > > > > do the calculation and checks and then move the
>> > > > > > > SR_BP3_BIT5
>> > > > > > > to
>> > > > > > > SR_BP3_BIT6
>> > > > > > > if SNOR_F_HAS_SR_BP3_BIT6 is set.
>> > > > > > >
>> > > > > >
>> > > > > > For most of flashes that supporting BP0-2, the smallest
>> > > > > > protected
>> > > > > > portion is fixed as 1/64
>> > > > > > and it can be properly handled by existing
>> > > > > > calculation. (Actually it's not fully generic, see flashes
>> > > > > > like
>> > > > > > w25q40bw or m25p80. Of course, it doesn't have
>> > > > > > SPI_NOR_HAS_LOCK
>> > > > > > flag
>> > > > > > even though it has BP0-2 bit in SR)
>> > > > >
>> > > > > No. The rules are always the same wether there are three or
>> > > > > four
>> > > > > BP
>> > > > > bits (the example in stm_lock() has not enough information on
>> > > > > this):
>> > > > >
>> > > > > (1) the first setting (besides 0) protects one sector. The
>> > > > > second
>> > > > >      protects 2, the third 4 and so on. eg 2^N
>> > > > > (2) the last setting is _always_ protect all, just like the
>> > > > > '0'
>> > > > > setting
>> > > > >      is always protect none.
>> > > > > (3) if there is an overflow because there are no more free
>> > > > > slots
>> > > > > for
>> > > > >      further settings (for 3 bits with flashes > 32MBit, for
>> > > > > 4
>> > > > >      bits if should be flashes > 16GBit), the first entry
>> > > > > will be
>> > > > >      discarded (eg the very first is the "just one sector"
>> > > > > entry).
>> > > > >
>> > > > > This is true for all flashes which uses this kind of setting,
>> > > > > have a
>> > > > > look at the m25p80 or w25q40bw, these are no exception. It is
>> > > > > just
>> > > > > the
>> > > > > notation "lower 1/64" which is only true for flashes which
>> > > > > either
>> > > > > overflows in (3) or fill all entries (eg. with 3bits that
>> > > > > would
>> > > > > be
>> > > > > the
>> > > > > 32Mbit version).
>> > > > >
>> > > >
>> > > > Looks like you noticed that we need new calculation method that
>> > > > would
>> > > > be based on n_sectors :).
>> > >
>> > > No it will work without that (if I'm not mistaken). Give me some
>> > > time
>> > > and I'll post a patch.
>> >
>> > No, it must be based on n_sectors. To make 4bit block protection
>> > more
>> > generic, the lock sector size must NOT fixed as 64KB (as can be
>> > checked
>> > from your patch). See "mt35xu02g" and check the protected area and
>> > number of sectors from it's datasheet.
>> 
>> There is no public datasheet as far as I can see. And yes, actually
>> n_sectors is my "mtd-size / sector_size". But I don't see how
>> n_sectors
>> would help if the sector size changes.
>> 
>> > The rule you mentioned "the first setting (besides 0) protects one
>> > sector" is alawys true for *4bit* block protection. That's why I
>> > choose
>> > n_sectors for new calculation.
>> 
>> And how does flashes behave once all the free slots are full? It was
>> the
>> same with the 3bit flashes, they only overflowed with "newer"/bigger
>> flashes.
>> 
>> 
>> > >
>> > > > Rule (1) is NOT true for some flashes
>> > > > supporting BP0-2 and that's why I said that smallest protected
>> > > > portion
>> > > > is fixed as '1/64' for these flashes.
>> > >
>> > > No, you have to apply rule (3). (1) is only the starting point.
>> > > It
>> > > is
>> > > kind
>> > > of a sliding window.
>> > >
>> > > > See this one.
>> > > >
>> > > > W25Q20EW	256KB	1/4 ... = 64KB		BP2
>> > > > W25Q128JV	16MB	1/64 ... = 256KB	BP2 <--
>> > > > S25FL132K	4MB	1/64 ... = 64KB		BP2 <--
>> > > > S25FL164K	8MB
>> > > > 1/64 ... = 128KB	BP2 <--
>> > >
>> > > All these flashes need (3) to be applied, thus (1) doesn't apply
>> > > anymore.
>> > >
>> > > Let me give you an example for the 64MBit case, the settings
>> > > would
>> > > be:
>> > >
>> > > 0 sectors (corresponds to protect none)
>> > > 1 sector
>> > > 2 sectors
>> > > 4 sectors
>> > > 8 sectors
>> > > 16 sectors
>> > > 32 sectors
>> > > 64 sectors
>> > > 128 sectors (corresponds to protect all)
>> > >
>> > > Unfortunately, we have only 8 slots (because 3 BP bits),
>> > > therefore
>> > > we
>> > > have
>> > > to discard some setting. According to rule (2) 0 is always
>> > > "protect
>> > > none"
>> > > and 7 is always "protect all". Thus we have 6 settings left.
>> > > According
>> > > to
>> > > rule (3) we discard the first ones. In this case, this is the "1
>> > > sector"
>> > > setting. Thus we end up with the following possible settings:
>> > >
>> > > 0 sectors (corresponds to protect none)
>> > > 2 sectors
>> > > 4 sectors
>> > > 8 sectors
>> > > 16 sectors
>> > > 32 sectors
>> > > 64 sectors
>> > > 128 sectors (corresponds to protect all)
>> > >
>> > > If you have a 128Mbit flash, the next setting that would be
>> > > discarded
>> > > is
>> > > "2 sectors". Thus it would start with:
>> > >
>> > > 0 sectors (corresponds to protect none)
>> > > 4 sectors
>> > > [..]
>> > > 256 sectors (corresponds to protect all)
>> > >
>> > >
>> > > Another example W25Q20EW, following possible settings:
>> > >
>> > > 0 sectors (corresponds to protect none)
>> > > 1 sector
>> > > 2 sectors
>> > > 4 sectors (corresponds to protect all)
>> > >
>> > > We now have less settings then our 8 possible slots. So this is
>> > > where
>> > > rule (1) applies, because according to that the "1 sector"
>> > > setting is
>> > > the first possible setting besides 0.
>> > >
>> > > And this also applies to the 4 bit protection bits.
>> > >
>> > >
>> > >
>> > > > W25Q256JV	32MB	1/512 ... =
>> > > > 64KB	BP3
>> > > > S25FL128L	16MB	1/256 ... = 64KB	BP3
>> > > > S25FL256L	32MB	1/512 ... = 64KB	BP3
>> > > >
>> > > > In current BP implementation, block protection is just working
>> > > > for
>> > > > some
>> > > > flashes that has smallest protected portion as '1/64'.
>> > >
>> > > No its currently working for all except flashes smaller than
>> > > 32Mbit.
>> >
>> > No. Not working for flashes supporting 4bit block protection.
>> >
>> > > Applied to the 4 bits, this would mean "it works for all except
>> > > flashes
>> > > smaller than 8Gbit" which are practially all. As I said, this is
>> > > a
>> > > bug
>> > > and once this bug is fixed, there should be no difference between
>> > > 3
>> > > and 4 bits.
>> > >
>> > > -michael
>> > >
>> >
>> > The exact fact is that locks operate in two different ways
>> > according to
>> > flash model.
>> >
>> > (1) the smallest protected portion is fixed.
>> > 	for BP0-2 : 1/64
>> > 	for BP0-1 : 1/4
>> 
>> As mentioned earlier, the ratio nomenclature is missleading and only
>> valid if the table is completely filled up.
>> 
>> Take a flash with 128kB and three BP bits (or even only two BP
>> bits).
>> The
>> smallest portion will be 64kB (which is one sector and not 1/64).
>> 
>> Thus the smallest portion is always one sector, unless the table is
>> overflowing, then the smallest will settle to 1/4 (for two), 1/64
>> (for
>> three)
>> and 1/16384 (for four bits).
>> 
>> > (2) the smallest protected portion is inversely propotional with
>> > number
>> > of sectors.
>> >
>> > For the flashes supporting 3bit block protection, (1) and (2) are
>> > mixed
>> > and used. But all the flashes supporting 4bit block protection
>> > listed
>> > on spi-nor.c, only (2) is used.
>> 
>> It is not mixed it just depends on the flash size (and the number of
>> protection bits).
>> 
> 
> It is mixed. Let's compare "en25qh128" from EON with "w25q128jv" from
> Winbond. They have the same capacity(128MBit) and also supporting 3bit
> block protection. (Note that the named BP3 bit of "en25qh128" is
> working exactly same with T/B bit.)
> 
> "en25qh128" is following (2) and "w25q128jv" is following (1). It seems
> impossible to distinguish them by the flash size or the number of
> protection bits.
> 
> I also still have no idea how your three rules are applicable for 2bit
> block protection (bp0-1).
> 
>> > Each method requires each formula. I have no idea how to handle it
>> > with
>> > one formula (probably adding number of exceptional handling?)
>> > without
>> > any sectional flag. "w25q128jv(bp0-2)" is following (1) and
>> > "n25q128a(bp0-3)" is following (2).
>> 
>> Well one uses three BPs the other four, and they all follow the
>> three
>> rules
>> above. Did you try my patch? Because I've (at least in userspace)
>> tested
>> it with 4 bits and got the correct results.
>> 
>> And yes, its actually two different formulas, but not for 3 and 4
>> bits like in your patch.
> 
> The title of my patch is "add 4bit block protection support". I just
> let 3bit block protection as it is, I've implemented something what I
> could check. As I mentioned, for all the flashes supporting 4bit block
> protection only (2) is used and this patch has been implemented based
> on this fact.

You fail to see that there is also a bug in the 3bit support and once
that bug is fixed, it also works for the 4bit support. So, I'm asking
again, did you test my patch?

> 
>> It is rather one formula (A) for flashes which don't
>> exhaust
>> the BP bits (eg. for 3 bits this would be flashes <= 16Mbit and for
>> 4
>> bits
>> this would be for flashes <=8Gbit) and one (B) for the flashes where
>> every
>> BP bit combination is used. What is at the moment in the kernel is
>> the
>> second one, thus it will fail for flashes <= 16Mbit and 3 BP bits;
>> and
>> it
>> also fails for all flashes with 4 bits. My patch does a fixup on (B)
>> to
>> match the results of (A), because doing this is less invasive; and as
>> mentioned in the patch annex, might also be rewritten for a better
>> understanding.
> 
> I've never seen spi flashes greater than 8Gbit (maybe you also), so I
> am not sure whether the three rules are applicable to 4 bit block
> protection. Even the three rules doesn't seem to be general enough for
> 3bit or 2bit block protection.
> 
>> 
>> 
>> -michael
>> 
>> >
>> > > >
>> > > > We need new fomula based on n_sectors for BP3 at least.
>> > >
>> > > No they are the same, but yes there is a bug in the current
>> > > implementation.
>> > >
>> > > -michael
>> > >
>> > > >
>> > > > > So for the 3 bit case the following flashes are border cases:
>> > > > >   - 16mbit (less settings than slots)
>> > > > >   - 32mbit (number of settings and free slots match)
>> > > > >   - 64mbit (more settings than slots, first setting is
>> > > > > discarded)
>> > > > >
>> > > > > That being said, I suspect all the 16mbit flashes (and below)
>> > > > > which
>> > > > > have
>> > > > > the _LOCK bit set are broken, because the entries has to be
>> > > > > shifted.
>> > > > > I'll
>> > > > > look into that later. This is the same "issue" you have with
>> > > > > the
>> > > > > 4
>> > > > > bits.
>> > > > > So if this is fixed, you should not need another formula for
>> > > > > the
>> > > > > 4
>> > > > > bit
>> > > > > case.
>> > > > >
>> > > > > > We need new calculation method for 4bit block protection
>> > > > > > and
>> > > > > > for
>> > > > > > making
>> > > > > > it more generic, I choose n_sectors.
>> > > > > >
>> > > > > > On all the flashes I checked, n_sectors is proper value for
>> > > > > > getting
>> > > > > > block protected portion.
>> > > > > >
>> > > > > > 		density	portion	n_sectors
>> > > > > > W25M512JV	64MB	1/512	512
>> > > > > > N25Q128A	16MB	1/256	256
>> > > > > > N25Q512A	64MB	1/1024	1024
>> > > > > > MT25QL02GCBB	256MB	1/4096	4096
>> > > > >
>> > > > > The rules above apply to these flashes, too. Could you double
>> > > > > check
>> > > > > that?
>> > > > >
>> > > > > -michael
>> > > > >
>> > > > > >
>> > > > > > > > +		val = val << SR_BP_SHIFT;
>> > > > > > > > +
>> > > > > > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
>> > > > > > > > +			val = (val & ~BIT(5)) | BIT(6);
>> > > > > > > > +	} else {
>> > > > > > > > +		val = mask - (pow << SR_BP_SHIFT);
>> > > > > > > > +	}
>> > > > > > > > +
>> > > > > > > >  	if (val & ~mask)
>> > > > > > > >  		return -EINVAL;
>> > > > > > > >  	/* Don't "lock" with no region! */
>> > > > > > > > @@ -1983,6 +2057,13 @@ static int stm_unlock(struct
>> > > > > > > > spi_nor
>> > > > > > > > *nor,
>> > > > > > > > loff_t ofs, uint64_t len)
>> > > > > > > >
>> > > > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>> > > > > > > >  		tb_mask = SR_TB_BIT6;
>> > > > > > > > +
>> > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > > > > > +		if (nor->flags &
>> > > > > > > > SNOR_F_HAS_SR_BP3_BIT6)
>> > > > > > > > +			mask = mask | SR_BP3_BIT6;
>> > > > > > > > +		else
>> > > > > > > > +			mask = mask | SR_BP3_BIT5;
>> > > > > > > > +	}
>> > > > > > > >  	/*
>> > > > > > > >  	 * Need largest pow such that:
>> > > > > > > >  	 *
>> > > > > > > > @@ -1995,13 +2076,20 @@ static int stm_unlock(struct
>> > > > > > > > spi_nor
>> > > > > > > > *nor,
>> > > > > > > > loff_t ofs, uint64_t len)
>> > > > > > > >  	pow = ilog2(mtd->size) -
>> > > > > > > > order_base_2(lock_len);
>> > > > > > > >  	if (lock_len == 0) {
>> > > > > > > >  		val = 0; /* fully unlocked */
>> > > > > > > > +	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> > > > > > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
>> > > > > > > > +		val = val << SR_BP_SHIFT;
>> > > > > > > > +
>> > > > > > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
>> > > > > > > > +			val = (val & ~BIT(5)) | BIT(6);
>> > > > > > > >  	} else {
>> > > > > > > >  		val = mask - (pow << SR_BP_SHIFT);
>> > > > > > > > -		/* Some power-of-two sizes are not
>> > > > > > > > supported */
>> > > > > > > > -		if (val & ~mask)
>> > > > > > > > -			return -EINVAL;
>> > > > > > > >  	}
>> > > > > > > >
>> > > > > > > > +	/* Some power-of-two sizes are not supported */
>> > > > > > > > +	if (val & ~mask)
>> > > > > > > > +		return -EINVAL;
>> > > > > > > > +
>> > > > > > > >  	status_new = (status_old & ~mask & ~tb_mask) |
>> > > > > > > > val;
>> > > > > > > >
>> > > > > > > >  	/* Don't protect status register if we're fully
>> > > > > > > > unlocked */
>> > > > > > > > @@ -4736,6 +4824,7 @@ static void
>> > > > > > > > spi_nor_info_init_params(struct
>> > > > > > > > spi_nor *nor)
>> > > > > > > >  	/* Set SPI NOR sizes. */
>> > > > > > > >  	params->size = (u64)info->sector_size * info-
>> > > > > > > > > n_sectors;
>> > > > > > > >
>> > > > > > > >  	params->page_size = info->page_size;
>> > > > > > > > +	params->n_sectors = info->n_sectors;
>> > > > > > > >
>> > > > > > > >  	if (!(info->flags & SPI_NOR_NO_FR)) {
>> > > > > > > >  		/* Default to Fast Read for DT and non-
>> > > > > > > > DT
>> > > > > > > > platform
>> > > > > > > > devices. */
>> > > > > > > > @@ -5192,6 +5281,11 @@ int spi_nor_scan(struct spi_nor
>> > > > > > > > *nor,
>> > > > > > > > const
>> > > > > > > > char *name,
>> > > > > > > >  		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
>> > > > > > > >  	if (info->flags & USE_CLSR)
>> > > > > > > >  		nor->flags |= SNOR_F_USE_CLSR;
>> > > > > > > > +	if (info->flags & SPI_NOR_HAS_BP3) {
>> > > > > > > > +		nor->flags |= SNOR_F_HAS_SR_BP3;
>> > > > > > > > +		if (info->flags & SPI_NOR_BP3_SR_BIT6)
>> > > > > > > > +			nor->flags |=
>> > > > > > > > SNOR_F_HAS_SR_BP3_BIT6;
>> > > > > > > > +	}
>> > > > > > > >
>> > > > > > > >  	if (info->flags & SPI_NOR_NO_ERASE)
>> > > > > > > >  		mtd->flags |= MTD_NO_ERASE;
>> > > > > > > > @@ -5199,6 +5293,7 @@ int spi_nor_scan(struct spi_nor
>> > > > > > > > *nor,
>> > > > > > > > const
>> > > > > > > > char *name,
>> > > > > > > >  	mtd->dev.parent = dev;
>> > > > > > > >  	nor->page_size = params->page_size;
>> > > > > > > >  	mtd->writebufsize = nor->page_size;
>> > > > > > > > +	nor->n_sectors = params->n_sectors;
>> > > > > > > >
>> > > > > > > >  	if (of_property_read_bool(np, "broken-flash-
>> > > > > > > > reset"))
>> > > > > > > >  		nor->flags |= SNOR_F_BROKEN_RESET;
>> > > > > > > > diff --git a/include/linux/mtd/spi-nor.h
>> > > > > > > > b/include/linux/mtd/spi-
>> > > > > > > > nor.h
>> > > > > > > > index 541c06d042e8..92d550501daf 100644
>> > > > > > > > --- a/include/linux/mtd/spi-nor.h
>> > > > > > > > +++ b/include/linux/mtd/spi-nor.h
>> > > > > > > > @@ -129,7 +129,9 @@
>> > > > > > > >  #define SR_BP1			BIT(3)	/* Block
>> > > > > > > > protect 1
>> > > > > > > > */
>> > > > > > > >  #define SR_BP2			BIT(4)	/* Block
>> > > > > > > > protect 2
>> > > > > > > > */
>> > > > > > > >  #define SR_TB_BIT5		BIT(5)	/* Top/Bottom
>> > > > > > > > protect
>> > > > > > > > */
>> > > > > > > > +#define SR_BP3_BIT5		BIT(5)	/* Block
>> > > > > > > > protect 3
>> > > > > > > > */
>> > > > > > >
>> > > > > > > maybe just name it SR_BP3? would also be more consistent
>> > > > > > > with
>> > > > > > > the
>> > > > > > > proposal
>> > > > > > > above.
>> > > > > > >
>> > > > > > > >  #define SR_TB_BIT6		BIT(6)	/* Top/Bottom
>> > > > > > > > protect
>> > > > > > > > */
>> > > > > > > > +#define SR_BP3_BIT6		BIT(6)	/* Block
>> > > > > > > > protect 3
>> > > > > > > > */
>> > > > > > > >  #define SR_SRWD			BIT(7)	/* SR
>> > > > > > > > write
>> > > > > > > > protect
>> > > > > > > > */
>> > > > > > > >  /* Spansion/Cypress specific status bits */
>> > > > > > > >  #define SR_E_ERR		BIT(5)
>> > > > > > > > @@ -248,6 +250,8 @@ enum spi_nor_option_flags {
>> > > > > > > >  	SNOR_F_HAS_16BIT_SR	= BIT(9),
>> > > > > > > >  	SNOR_F_NO_READ_CR	= BIT(10),
>> > > > > > > >  	SNOR_F_HAS_SR_TB_BIT6	= BIT(11),
>> > > > > > > > +	SNOR_F_HAS_SR_BP3	= BIT(12),
>> > > > > > > > +	SNOR_F_HAS_SR_BP3_BIT6	= BIT(13),
>> > > > > > > >
>> > > > > > > >  };
>> > > > > > > >
>> > > > > > > > @@ -519,6 +523,7 @@ struct spi_nor_locking_ops {
>> > > > > > > >   *
>> > > > > > > >   * @size:		the flash memory density in
>> > > > > > > > bytes.
>> > > > > > > >   * @page_size:		the page size of the SPI NOR
>> > > > > > > > flash
>> > > > > > > > memory.
>> > > > > > > > + * @n_sectors:		number of sectors
>> > > > > > > >   * @hwcaps:		describes the read and page
>> > > > > > > > program
>> > > > > > > > hardware
>> > > > > > > >   *			capabilities.
>> > > > > > > >   * @reads:		read capabilities ordered by
>> > > > > > > > priority:
>> > > > > > > > the
>> > > > > > > > higher index
>> > > > > > > > @@ -541,6 +546,7 @@ struct spi_nor_locking_ops {
>> > > > > > > >  struct spi_nor_flash_parameter {
>> > > > > > > >  	u64				size;
>> > > > > > > >  	u32				page_size;
>> > > > > > > > +	u16				n_sectors;
>> > > > > > > >
>> > > > > > > >  	struct spi_nor_hwcaps		hwcaps;
>> > > > > > > >  	struct spi_nor_read_command	reads[SNOR_CMD_
>> > > > > > > > READ_MAX
>> > > > > > > > ];
>> > > > > > > > @@ -573,6 +579,7 @@ struct flash_info;
>> > > > > > > >   * @bouncebuf_size:	size of the bounce buffer
>> > > > > > > >   * @info:		spi-nor part JDEC MFR id and
>> > > > > > > > other info
>> > > > > > > >   * @page_size:		the page size of the SPI NOR
>> > > > > > > > + * @n_sector:		number of sectors
>> > > > > > > >   * @addr_width:		number of address bytes
>> > > > > > > >   * @erase_opcode:	the opcode for erasing a sector
>> > > > > > > >   * @read_opcode:	the read opcode
>> > > > > > > > @@ -599,6 +606,7 @@ struct spi_nor {
>> > > > > > > >  	size_t			bouncebuf_size;
>> > > > > > > >  	const struct flash_info	*info;
>> > > > > > > >  	u32			page_size;
>> > > > > > > > +	u16			n_sectors;
>> > > > > > > >  	u8			addr_width;
>> > > > > > > >  	u8			erase_opcode;
>> > > > > > > >  	u8			read_opcode;
>> > > > > > > > --
>> > > > > > > > 2.17.1
>> > > > > > > >
>> > > > > > > >
>> > > > > > > > ______________________________________________________
>> > > > > > > > Linux MTD discussion mailing list
>> > > > > > > >
>> > > > > >
>> > > > > >
>> > > >
>> > > >
>> >
>> >
> https://protect2.fireeye.com/url?k=06b6dd5d-5b7d5a63-06b75612-0cc47a31309a-83164929001f7741&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
>> > > > > > > >
>> > > > > > >
>> > > > > > >
>> > > > >
>> > > > >
>> > >
>> > >
>> 
>> 
> 
> Thanks,
> Jungseung Lee

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Hi, Michael

2020-01-30 (목), 09:36 +0100, Michael Walle:
> Hi Jungseung,
> 
> Am 2020-01-30 09:17, schrieb Jungseung Lee:
> > Hi, Michael
> > 
> > 2020-01-28 (화), 13:29 +0100, Michael Walle:
> > > Am 2020-01-28 12:01, schrieb Jungseung Lee:
> > > > Hi, Michael
> > > > 
> > > > 2020-01-23 (Thu), 10:31 +0100, Michael Walle:
> > > > > Am 2020-01-23 09:53, schrieb Jungseung Lee:
> > > > > > Hi, Michael
> > > > > > 
> > > > > > 2020-01-23 (Thu), 09:10 +0100, Michael Walle:
> > > > > > > Hi Jungseung,
> > > > > > > 
> > > > > > > Am 2020-01-23 07:22, schrieb Jungseung Lee:
> > > > > > > > Hi, Michael
> > > > > > > > 
> > > > > > > > 2020-01-22 (Wed), 20:36 +0100, Michael Walle:
> > > > > > > > > Hi,
> > > > > > > > > 
> > > > > > > > > > Currently, we are supporting block protection only
> > > > > > > > > > for
> > > > > > > > > > flash chips with 3 block protection bits in the SR
> > > > > > > > > > register.
> > > > > > > > > > This patch enables block protection support for
> > > > > > > > > > some
> > > > > > > > > > flash
> > > > > > > > > > with
> > > > > > > > > > 4 block protection bits(bp0-3).
> > > > > > > > > > 
> > > > > > > > > > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> > > > > > > > > > ---
> > > > > > > > > > v3 :
> > > > > > > > > >   Fix wrong ofs calculation on v2 patch
> > > > > > > > > > v2 :
> > > > > > > > > >   Add sample table portion about 4bit block
> > > > > > > > > > protection
> > > > > > > > > > on
> > > > > > > > > > the
> > > > > > > > > > comment
> > > > > > > > > >   Trivial coding style change
> > > > > > > > > > 
> > > > > > > > > >  drivers/mtd/spi-nor/spi-nor.c | 127
> > > > > > > > > > +++++++++++++++++++++++++++++-
> > > > > > > > > > ----
> > > > > > > > > >  include/linux/mtd/spi-nor.h   |   8 +++
> > > > > > > > > >  2 files changed, 119 insertions(+), 16 deletions(-
> > > > > > > > > > )
> > > > > > > > > > 
> > > > > > > > > > diff --git a/drivers/mtd/spi-nor/spi-nor.c
> > > > > > > > > > b/drivers/mtd/spi-
> > > > > > > > > > nor/spi-nor.c
> > > > > > > > > > index e3da6a8654a8..7e8af6c4fdfa 100644
> > > > > > > > > > --- a/drivers/mtd/spi-nor/spi-nor.c
> > > > > > > > > > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > > > > > > > > > @@ -238,6 +238,14 @@ struct flash_info {
> > > > > > > > > >  					 * status
> > > > > > > > > > register.
> > > > > > > > > > Must be
> > > > > > > > > > used with
> > > > > > > > > >  					 *
> > > > > > > > > > SPI_NOR_HAS_TB.
> > > > > > > > > >  					 */
> > > > > > > > > > +#define SPI_NOR_HAS_BP3		BIT(17)	/*
> > > > > > > > > > +					 * Flash SR has
> > > > > > > > > > 4 bit
> > > > > > > > > > fields
> > > > > > > > > > (BP0-3)
> > > > > > > > > > +					 * for block
> > > > > > > > > > protection.
> > > > > > > > > > +					 */
> > > > > > > > > > +#define SPI_NOR_BP3_SR_BIT6	BIT(18)	/*
> > > > > > > > > > +					 * BP3 is bit 6
> > > > > > > > > > of
> > > > > > > > > > status
> > > > > > > > > > register.
> > > > > > > > > > +					 * Must be used
> > > > > > > > > > with
> > > > > > > > > > SPI_NOR_HAS_BP3.
> > > > > > > > > > +					 */
> > > > > > > > > > 
> > > > > > > > > >  	/* Part specific fixup hooks. */
> > > > > > > > > >  	const struct spi_nor_fixups *fixups;
> > > > > > > > > > @@ -1767,23 +1775,47 @@ static void
> > > > > > > > > > stm_get_locked_range(struct
> > > > > > > > > > spi_nor *nor, u8 sr, loff_t *ofs,
> > > > > > > > > >  	struct mtd_info *mtd = &nor->mtd;
> > > > > > > > > >  	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
> > > > > > > > > >  	u8 tb_mask = SR_TB_BIT5;
> > > > > > > > > > -	int pow;
> > > > > > > > > > +	u8 bp;
> > > > > > > > > > +	int pow = 0;
> > > > > > > > > > 
> > > > > > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> > > > > > > > > >  		tb_mask = SR_TB_BIT6;
> > > > > > > > > > 
> > > > > > > > > > -	if (!(sr & mask)) {
> > > > > > > > > > -		/* No protection */
> > > > > > > > > > -		*ofs = 0;
> > > > > > > > > > -		*len = 0;
> > > > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > > > > > +		u8 tmp;
> > > > > > > > > > +
> > > > > > > > > > +		if (nor->flags &
> > > > > > > > > > SNOR_F_HAS_SR_BP3_BIT6)
> > > > > > > > > > +			tmp = sr & (mask |
> > > > > > > > > > SR_BP3_BIT6);
> > > > > > > > > > +		else
> > > > > > > > > > +			tmp = sr & (mask |
> > > > > > > > > > SR_BP3_BIT5);
> > > > > > > > > > +
> > > > > > > > > > +		if (tmp & SR_BP3_BIT6)
> > > > > > > > > > +			tmp = (tmp & ~BIT(6)) | BIT(5);
> > > > > > > > > > +
> > > > > > > > > > +		bp = tmp >> SR_BP_SHIFT;
> > > > > > > > > > +		if (!bp) {
> > > > > > > > > > +			*ofs = 0;
> > > > > > > > > > +			*len = 0;
> > > > > > > > > > +			return;
> > > > > > > > > > +		}
> > > > > > > > > > +		if (bp <= ilog2(nor->n_sectors))
> > > > > > > > > > +			pow = ilog2(nor->n_sectors) + 1
> > > > > > > > > > - bp;
> > > > > > > > > >  	} else {
> > > > > > > > > > -		pow = ((sr & mask) ^ mask) >>
> > > > > > > > > > SR_BP_SHIFT;
> > > > > > > > > > -		*len = mtd->size >> pow;
> > > > > > > > > > -		if (nor->flags & SNOR_F_HAS_SR_TB && sr
> > > > > > > > > > &
> > > > > > > > > > tb_mask)
> > > > > > > > > > +		bp = (sr & mask) >> SR_BP_SHIFT;
> > > > > > > > > > +		if (!bp) {
> > > > > > > > > >  			*ofs = 0;
> > > > > > > > > > -		else
> > > > > > > > > > -			*ofs = mtd->size - *len;
> > > > > > > > > > +			*len = 0;
> > > > > > > > > > +			return;
> > > > > > > > > > +		}
> > > > > > > > > > +		pow = bp ^ (mask >> SR_BP_SHIFT);
> > > > > > > > > >  	}
> > > > > > > > > > +
> > > > > > > > > > +	*len = mtd->size >> pow;
> > > > > > > > > > +
> > > > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_TB && sr &
> > > > > > > > > > tb_mask)
> > > > > > > > > > +		*ofs = 0;
> > > > > > > > > > +	else
> > > > > > > > > > +		*ofs = mtd->size - *len;
> > > > > > > > > >  }
> > > > > > > > > > 
> > > > > > > > > >  /*
> > > > > > > > > > @@ -1823,7 +1855,7 @@ static int
> > > > > > > > > > stm_is_unlocked_sr(struct
> > > > > > > > > > spi_nor
> > > > > > > > > > *nor, loff_t ofs, uint64_t len,
> > > > > > > > > > 
> > > > > > > > > >  /*
> > > > > > > > > >   * Lock a region of the flash. Compatible with ST
> > > > > > > > > > Micro
> > > > > > > > > > and
> > > > > > > > > > similar flash.
> > > > > > > > > > - * Supports the block protection bits BP{0,1,2} in
> > > > > > > > > > the
> > > > > > > > > > status
> > > > > > > > > > register
> > > > > > > > > > + * Supports the block protection bits BP{0,1,2,3}
> > > > > > > > > > in
> > > > > > > > > > the
> > > > > > > > > > status
> > > > > > > > > > register
> > > > > > > > > >   * (SR). Does not support these features found in
> > > > > > > > > > newer SR
> > > > > > > > > > bitfields:
> > > > > > > > > >   *   - SEC: sector/block protect - only handle
> > > > > > > > > > SEC=0
> > > > > > > > > > (block
> > > > > > > > > > protect)
> > > > > > > > > >   *   - CMP: complement protect - only support
> > > > > > > > > > CMP=0
> > > > > > > > > > (range
> > > > > > > > > > is
> > > > > > > > > > not
> > > > > > > > > > complemented)
> > > > > > > > > > @@ -1831,7 +1863,7 @@ static int
> > > > > > > > > > stm_is_unlocked_sr(struct
> > > > > > > > > > spi_nor
> > > > > > > > > > *nor, loff_t ofs, uint64_t len,
> > > > > > > > > >   * Support for the following is provided
> > > > > > > > > > conditionally
> > > > > > > > > > for
> > > > > > > > > > some
> > > > > > > > > > flash:
> > > > > > > > > >   *   - TB: top/bottom protect
> > > > > > > > > >   *
> > > > > > > > > > - * Sample table portion for 8MB flash (Winbond
> > > > > > > > > > w25q64fw):
> > > > > > > > > > + * Sample table portion for 8MB flash (Winbond
> > > > > > > > > > w25q64fw /
> > > > > > > > > > BP0-
> > > > > > > > > > 2):
> > > > > > > > > >   *
> > > > > > > > > >   *   SEC  |  TB   |  BP2  |  BP1  |  BP0  |  Prot
> > > > > > > > > > Length  |
> > > > > > > > > > Protected Portion
> > > > > > > > > >   *  --------------------------------------------
> > > > > > > > > > ----
> > > > > > > > > > ----
> > > > > > > > > > ----
> > > > > > > > > > ----
> > > > > > > > > > --------------
> > > > > > > > > > @@ -1851,6 +1883,32 @@ static int
> > > > > > > > > > stm_is_unlocked_sr(struct
> > > > > > > > > > spi_nor
> > > > > > > > > > *nor, loff_t ofs, uint64_t len,
> > > > > > > > > >   *    0   |   1   |   1   |   0   |   1   |  2
> > > > > > > > > > MB         |
> > > > > > > > > > Lower
> > > > > > > > > > 1/4
> > > > > > > > > >   *    0   |   1   |   1   |   1   |   0   |  4
> > > > > > > > > > MB         |
> > > > > > > > > > Lower
> > > > > > > > > > 1/2
> > > > > > > > > >   *
> > > > > > > > > > + * Sample table portion for 64MB flash (Micron
> > > > > > > > > > n25q512ax3
> > > > > > > > > > /
> > > > > > > > > > BP0-
> > > > > > > > > > 3):
> > > > > > > > > > + *
> > > > > > > > > > + *   TB   |  BP3  |  BP2  |  BP1  |  BP0  |  Prot
> > > > > > > > > > Length  |
> > > > > > > > > > Protected Portion
> > > > > > > > > > + *  --------------------------------------------
> > > > > > > > > > ----
> > > > > > > > > > ----
> > > > > > > > > > ----
> > > > > > > > > > ----
> > > > > > > > > > --------------
> > > > > > > > > > +
> > > > > > > > > > *    0   |   0   |   0   |   0   |   0   |  NONE
> > > > > > > > > >   |
> > > > > > > > > > NONE
> > > > > > > > > > + *    0   |   0   |   0   |   0   |   1   |   64
> > > > > > > > > > KB       |
> > > > > > > > > > Upper
> > > > > > > > > > 1/1024
> > > > > > > > > > + *    0   |   0   |   0   |   1   |   0   |  128
> > > > > > > > > > KB       |
> > > > > > > > > > Upper
> > > > > > > > > > 1/512
> > > > > > > > > > + *    0   |   0   |   0   |   1   |   1   |  256
> > > > > > > > > > KB       |
> > > > > > > > > > Upper
> > > > > > > > > > 1/256
> > > > > > > > > > + *   ...
> > > > > > > > > > + *    0   |   1   |   0   |   0   |   1   |  16
> > > > > > > > > > MB        |
> > > > > > > > > > Upper
> > > > > > > > > > 1/4
> > > > > > > > > > + *    0   |   1   |   0   |   1   |   0   |  32
> > > > > > > > > > MB        |
> > > > > > > > > > Upper
> > > > > > > > > > 1/2
> > > > > > > > > > + *    0   |   1   |   0   |   1   |   1   |  64
> > > > > > > > > > MB        |
> > > > > > > > > > ALL
> > > > > > > > > > + *    0   |   1   |   1   |   0   |   0   |  64
> > > > > > > > > > MB        |
> > > > > > > > > > ALL
> > > > > > > > > > + *   ...
> > > > > > > > > > + *  ------|-------|-------|-------|-------|-------
> > > > > > > > > > ----
> > > > > > > > > > ----
> > > > > > > > > > > ---
> > > > > > > > > > 
> > > > > > > > > > ----
> > > > > > > > > > ------------
> > > > > > > > > > +
> > > > > > > > > > *    1   |   0   |   0   |   0   |   0   |   NONE
> > > > > > > > > >   |
> > > > > > > > > > NONE
> > > > > > > > > > + *    1   |   0   |   0   |   0   |   1   |   64
> > > > > > > > > > KB       |
> > > > > > > > > > Lower
> > > > > > > > > > 1/1024
> > > > > > > > > > + *    1   |   0   |   0   |   1   |   0   |  128
> > > > > > > > > > KB       |
> > > > > > > > > > Lower
> > > > > > > > > > 1/512
> > > > > > > > > > + *    1   |   0   |   0   |   1   |   1   |  256
> > > > > > > > > > KB       |
> > > > > > > > > > Lower
> > > > > > > > > > 1/256
> > > > > > > > > > + *   ...
> > > > > > > > > > + *    1   |   1   |   0   |   0   |   1   |  16
> > > > > > > > > > MB        |
> > > > > > > > > > Lower
> > > > > > > > > > 1/4
> > > > > > > > > > + *    1   |   1   |   0   |   1   |   0   |  32
> > > > > > > > > > MB        |
> > > > > > > > > > Lower
> > > > > > > > > > 1/2
> > > > > > > > > > + *    1   |   1   |   0   |   1   |   1   |  64
> > > > > > > > > > MB        |
> > > > > > > > > > ALL
> > > > > > > > > > + *    1   |   1   |   1   |   0   |   0   |  64
> > > > > > > > > > MB        |
> > > > > > > > > > ALL
> > > > > > > > > > + *   ...
> > > > > > > > > > + *
> > > > > > > > > >   * Returns negative on errors, 0 on success.
> > > > > > > > > >   */
> > > > > > > > > >  static int stm_lock(struct spi_nor *nor, loff_t
> > > > > > > > > > ofs,
> > > > > > > > > > uint64_t
> > > > > > > > > > len)
> > > > > > > > > > @@ -1898,6 +1956,12 @@ static int stm_lock(struct
> > > > > > > > > > spi_nor
> > > > > > > > > > *nor,
> > > > > > > > > > loff_t ofs, uint64_t len)
> > > > > > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> > > > > > > > > >  		tb_mask = SR_TB_BIT6;
> > > > > > > > > > 
> > > > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > > > > > +		if (nor->flags &
> > > > > > > > > > SNOR_F_HAS_SR_BP3_BIT6)
> > > > > > > > > > +			mask = mask | SR_BP3_BIT6;
> > > > > > > > > > +		else
> > > > > > > > > > +			mask = mask | SR_BP3_BIT5;
> > > > > > > > > > +	}
> > > > > > > > > >  	/*
> > > > > > > > > >  	 * Need smallest pow such that:
> > > > > > > > > >  	 *
> > > > > > > > > > @@ -1908,7 +1972,17 @@ static int stm_lock(struct
> > > > > > > > > > spi_nor
> > > > > > > > > > *nor,
> > > > > > > > > > loff_t ofs, uint64_t len)
> > > > > > > > > >  	 *   pow = ceil(log2(size / len)) = log2(size)
> > > > > > > > > > -
> > > > > > > > > > floor(log2(len))
> > > > > > > > > >  	 */
> > > > > > > > > >  	pow = ilog2(mtd->size) - ilog2(lock_len);
> > > > > > > > > > -	val = mask - (pow << SR_BP_SHIFT);
> > > > > > > > > > +
> > > > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > > > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
> > > > > > > > > 
> > > > > > > > > Why do you use a new calculation here? As far as I
> > > > > > > > > can
> > > > > > > > > see,
> > > > > > > > > the
> > > > > > > > > method is
> > > > > > > > > the same except that is has one bit more. That also
> > > > > > > > > raises
> > > > > > > > > the
> > > > > > > > > question why
> > > > > > > > > n_sectors is now needed?
> > > > > > > > > 
> > > > > > > > > Can't we just initialize the mask with
> > > > > > > > > 
> > > > > > > > > mask = SR_BP2 | SR_BP1 | SR_BP0;
> > > > > > > > > if (nor->flags & SNOR_F_HAS_SR_BP3)
> > > > > > > > >     mask |= SR_BP3_BIT5;
> > > > > > > > > 
> > > > > > > > > do the calculation and checks and then move the
> > > > > > > > > SR_BP3_BIT5
> > > > > > > > > to
> > > > > > > > > SR_BP3_BIT6
> > > > > > > > > if SNOR_F_HAS_SR_BP3_BIT6 is set.
> > > > > > > > > 
> > > > > > > > 
> > > > > > > > For most of flashes that supporting BP0-2, the smallest
> > > > > > > > protected
> > > > > > > > portion is fixed as 1/64
> > > > > > > > and it can be properly handled by existing
> > > > > > > > calculation. (Actually it's not fully generic, see
> > > > > > > > flashes
> > > > > > > > like
> > > > > > > > w25q40bw or m25p80. Of course, it doesn't have
> > > > > > > > SPI_NOR_HAS_LOCK
> > > > > > > > flag
> > > > > > > > even though it has BP0-2 bit in SR)
> > > > > > > 
> > > > > > > No. The rules are always the same wether there are three
> > > > > > > or
> > > > > > > four
> > > > > > > BP
> > > > > > > bits (the example in stm_lock() has not enough
> > > > > > > information on
> > > > > > > this):
> > > > > > > 
> > > > > > > (1) the first setting (besides 0) protects one sector.
> > > > > > > The
> > > > > > > second
> > > > > > >      protects 2, the third 4 and so on. eg 2^N
> > > > > > > (2) the last setting is _always_ protect all, just like
> > > > > > > the
> > > > > > > '0'
> > > > > > > setting
> > > > > > >      is always protect none.
> > > > > > > (3) if there is an overflow because there are no more
> > > > > > > free
> > > > > > > slots
> > > > > > > for
> > > > > > >      further settings (for 3 bits with flashes > 32MBit,
> > > > > > > for
> > > > > > > 4
> > > > > > >      bits if should be flashes > 16GBit), the first entry
> > > > > > > will be
> > > > > > >      discarded (eg the very first is the "just one
> > > > > > > sector"
> > > > > > > entry).
> > > > > > > 
> > > > > > > This is true for all flashes which uses this kind of
> > > > > > > setting,
> > > > > > > have a
> > > > > > > look at the m25p80 or w25q40bw, these are no exception.
> > > > > > > It is
> > > > > > > just
> > > > > > > the
> > > > > > > notation "lower 1/64" which is only true for flashes
> > > > > > > which
> > > > > > > either
> > > > > > > overflows in (3) or fill all entries (eg. with 3bits that
> > > > > > > would
> > > > > > > be
> > > > > > > the
> > > > > > > 32Mbit version).
> > > > > > > 
> > > > > > 
> > > > > > Looks like you noticed that we need new calculation method
> > > > > > that
> > > > > > would
> > > > > > be based on n_sectors :).
> > > > > 
> > > > > No it will work without that (if I'm not mistaken). Give me
> > > > > some
> > > > > time
> > > > > and I'll post a patch.
> > > > 
> > > > No, it must be based on n_sectors. To make 4bit block
> > > > protection
> > > > more
> > > > generic, the lock sector size must NOT fixed as 64KB (as can be
> > > > checked
> > > > from your patch). See "mt35xu02g" and check the protected area
> > > > and
> > > > number of sectors from it's datasheet.
> > > 
> > > There is no public datasheet as far as I can see. And yes,
> > > actually
> > > n_sectors is my "mtd-size / sector_size". But I don't see how
> > > n_sectors
> > > would help if the sector size changes.
> > > 
> > > > The rule you mentioned "the first setting (besides 0) protects
> > > > one
> > > > sector" is alawys true for *4bit* block protection. That's why
> > > > I
> > > > choose
> > > > n_sectors for new calculation.
> > > 
> > > And how does flashes behave once all the free slots are full? It
> > > was
> > > the
> > > same with the 3bit flashes, they only overflowed with
> > > "newer"/bigger
> > > flashes.
> > > 
> > > 
> > > > > 
> > > > > > Rule (1) is NOT true for some flashes
> > > > > > supporting BP0-2 and that's why I said that smallest
> > > > > > protected
> > > > > > portion
> > > > > > is fixed as '1/64' for these flashes.
> > > > > 
> > > > > No, you have to apply rule (3). (1) is only the starting
> > > > > point.
> > > > > It
> > > > > is
> > > > > kind
> > > > > of a sliding window.
> > > > > 
> > > > > > See this one.
> > > > > > 
> > > > > > W25Q20EW	256KB	1/4 ... = 64KB		BP2
> > > > > > W25Q128JV	16MB	1/64 ... = 256KB	BP2 <--
> > > > > > S25FL132K	4MB	1/64 ... = 64KB		BP2 <--
> > > > > > S25FL164K	8MB
> > > > > > 1/64 ... = 128KB	BP2 <--
> > > > > 
> > > > > All these flashes need (3) to be applied, thus (1) doesn't
> > > > > apply
> > > > > anymore.
> > > > > 
> > > > > Let me give you an example for the 64MBit case, the settings
> > > > > would
> > > > > be:
> > > > > 
> > > > > 0 sectors (corresponds to protect none)
> > > > > 1 sector
> > > > > 2 sectors
> > > > > 4 sectors
> > > > > 8 sectors
> > > > > 16 sectors
> > > > > 32 sectors
> > > > > 64 sectors
> > > > > 128 sectors (corresponds to protect all)
> > > > > 
> > > > > Unfortunately, we have only 8 slots (because 3 BP bits),
> > > > > therefore
> > > > > we
> > > > > have
> > > > > to discard some setting. According to rule (2) 0 is always
> > > > > "protect
> > > > > none"
> > > > > and 7 is always "protect all". Thus we have 6 settings left.
> > > > > According
> > > > > to
> > > > > rule (3) we discard the first ones. In this case, this is the
> > > > > "1
> > > > > sector"
> > > > > setting. Thus we end up with the following possible settings:
> > > > > 
> > > > > 0 sectors (corresponds to protect none)
> > > > > 2 sectors
> > > > > 4 sectors
> > > > > 8 sectors
> > > > > 16 sectors
> > > > > 32 sectors
> > > > > 64 sectors
> > > > > 128 sectors (corresponds to protect all)
> > > > > 
> > > > > If you have a 128Mbit flash, the next setting that would be
> > > > > discarded
> > > > > is
> > > > > "2 sectors". Thus it would start with:
> > > > > 
> > > > > 0 sectors (corresponds to protect none)
> > > > > 4 sectors
> > > > > [..]
> > > > > 256 sectors (corresponds to protect all)
> > > > > 
> > > > > 
> > > > > Another example W25Q20EW, following possible settings:
> > > > > 
> > > > > 0 sectors (corresponds to protect none)
> > > > > 1 sector
> > > > > 2 sectors
> > > > > 4 sectors (corresponds to protect all)
> > > > > 
> > > > > We now have less settings then our 8 possible slots. So this
> > > > > is
> > > > > where
> > > > > rule (1) applies, because according to that the "1 sector"
> > > > > setting is
> > > > > the first possible setting besides 0.
> > > > > 
> > > > > And this also applies to the 4 bit protection bits.
> > > > > 
> > > > > 
> > > > > 
> > > > > > W25Q256JV	32MB	1/512 ... =
> > > > > > 64KB	BP3
> > > > > > S25FL128L	16MB	1/256 ... = 64KB	BP3
> > > > > > S25FL256L	32MB	1/512 ... = 64KB	BP3
> > > > > > 
> > > > > > In current BP implementation, block protection is just
> > > > > > working
> > > > > > for
> > > > > > some
> > > > > > flashes that has smallest protected portion as '1/64'.
> > > > > 
> > > > > No its currently working for all except flashes smaller than
> > > > > 32Mbit.
> > > > 
> > > > No. Not working for flashes supporting 4bit block protection.
> > > > 
> > > > > Applied to the 4 bits, this would mean "it works for all
> > > > > except
> > > > > flashes
> > > > > smaller than 8Gbit" which are practially all. As I said, this
> > > > > is
> > > > > a
> > > > > bug
> > > > > and once this bug is fixed, there should be no difference
> > > > > between
> > > > > 3
> > > > > and 4 bits.
> > > > > 
> > > > > -michael
> > > > > 
> > > > 
> > > > The exact fact is that locks operate in two different ways
> > > > according to
> > > > flash model.
> > > > 
> > > > (1) the smallest protected portion is fixed.
> > > > 	for BP0-2 : 1/64
> > > > 	for BP0-1 : 1/4
> > > 
> > > As mentioned earlier, the ratio nomenclature is missleading and
> > > only
> > > valid if the table is completely filled up.
> > > 
> > > Take a flash with 128kB and three BP bits (or even only two BP
> > > bits).
> > > The
> > > smallest portion will be 64kB (which is one sector and not 1/64).
> > > 
> > > Thus the smallest portion is always one sector, unless the table
> > > is
> > > overflowing, then the smallest will settle to 1/4 (for two), 1/64
> > > (for
> > > three)
> > > and 1/16384 (for four bits).
> > > 
> > > > (2) the smallest protected portion is inversely propotional
> > > > with
> > > > number
> > > > of sectors.
> > > > 
> > > > For the flashes supporting 3bit block protection, (1) and (2)
> > > > are
> > > > mixed
> > > > and used. But all the flashes supporting 4bit block protection
> > > > listed
> > > > on spi-nor.c, only (2) is used.
> > > 
> > > It is not mixed it just depends on the flash size (and the number
> > > of
> > > protection bits).
> > > 
> > 
> > It is mixed. Let's compare "en25qh128" from EON with "w25q128jv"
> > from
> > Winbond. They have the same capacity(128MBit) and also supporting
> > 3bit
> > block protection. (Note that the named BP3 bit of "en25qh128" is
> > working exactly same with T/B bit.)
> > 
> > "en25qh128" is following (2) and "w25q128jv" is following (1). It
> > seems
> > impossible to distinguish them by the flash size or the number of
> > protection bits.
> > 
> > I also still have no idea how your three rules are applicable for
> > 2bit
> > block protection (bp0-1).
> > 
> > > > Each method requires each formula. I have no idea how to handle
> > > > it
> > > > with
> > > > one formula (probably adding number of exceptional handling?)
> > > > without
> > > > any sectional flag. "w25q128jv(bp0-2)" is following (1) and
> > > > "n25q128a(bp0-3)" is following (2).
> > > 
> > > Well one uses three BPs the other four, and they all follow the
> > > three
> > > rules
> > > above. Did you try my patch? Because I've (at least in userspace)
> > > tested
> > > it with 4 bits and got the correct results.
> > > 
> > > And yes, its actually two different formulas, but not for 3 and 4
> > > bits like in your patch.
> > 
> > The title of my patch is "add 4bit block protection support". I
> > just
> > let 3bit block protection as it is, I've implemented something what
> > I
> > could check. As I mentioned, for all the flashes supporting 4bit
> > block
> > protection only (2) is used and this patch has been implemented
> > based
> > on this fact.
> 
> You fail to see that there is also a bug in the 3bit support and once
> that bug is fixed, it also works for the 4bit support. So, I'm asking
> again, did you test my patch?
> 

I think you are the only person who calls it a bug. There is no agreed
specification related with the each bit of status register.(let me know
if I've got wrong.) If some vendor start production of flashes that
using BP bits as it's own way, does it suddenly change into a buggy
code?

SPI_NOR_HAS_LOCK only can be set on some flashes that could be handled
by existing calculation, and test is required to set the flag for each
flashes.(Tudor also require it) If the flag is set wrong for some
flashes, that is BUG.

Look at what I said in the previous mail.> For most of flashes that supporting BP0-2, the smallest protected
> portion is fixed as 1/64 and it can be properly handled by existing
> calculation. (Actually it's not fully generic, see flashes like
> w25q40bw or m25p80. Of course, it doesn't have SPI_NOR_HAS_LOCK flag
> even though it has BP0-2 bit in SR)

>
>  So, I'm asking again, did you test my patch?
> 

No. It was just partially reviewed.

> > 
> > > It is rather one formula (A) for flashes which don't
> > > exhaust
> > > the BP bits (eg. for 3 bits this would be flashes <= 16Mbit and
> > > for
> > > 4
> > > bits
> > > this would be for flashes <=8Gbit) and one (B) for the flashes
> > > where
> > > every
> > > BP bit combination is used. What is at the moment in the kernel
> > > is
> > > the
> > > second one, thus it will fail for flashes <= 16Mbit and 3 BP
> > > bits;
> > > and
> > > it
> > > also fails for all flashes with 4 bits. My patch does a fixup on
> > > (B)
> > > to
> > > match the results of (A), because doing this is less invasive;
> > > and as
> > > mentioned in the patch annex, might also be rewritten for a
> > > better
> > > understanding.
> > 
> > I've never seen spi flashes greater than 8Gbit (maybe you also), so
> > I
> > am not sure whether the three rules are applicable to 4 bit block
> > protection. Even the three rules doesn't seem to be general enough
> > for
> > 3bit or 2bit block protection.
> > 
> > > 
> > > 
> > > -michael
> > > 
> > > > 
> > > > > > 
> > > > > > We need new fomula based on n_sectors for BP3 at least.
> > > > > 
> > > > > No they are the same, but yes there is a bug in the current
> > > > > implementation.
> > > > > 
> > > > > -michael
> > > > > 
> > > > > > 
> > > > > > > So for the 3 bit case the following flashes are border
> > > > > > > cases:
> > > > > > >   - 16mbit (less settings than slots)
> > > > > > >   - 32mbit (number of settings and free slots match)
> > > > > > >   - 64mbit (more settings than slots, first setting is
> > > > > > > discarded)
> > > > > > > 
> > > > > > > That being said, I suspect all the 16mbit flashes (and
> > > > > > > below)
> > > > > > > which
> > > > > > > have
> > > > > > > the _LOCK bit set are broken, because the entries has to
> > > > > > > be
> > > > > > > shifted.
> > > > > > > I'll
> > > > > > > look into that later. This is the same "issue" you have
> > > > > > > with
> > > > > > > the
> > > > > > > 4
> > > > > > > bits.
> > > > > > > So if this is fixed, you should not need another formula
> > > > > > > for
> > > > > > > the
> > > > > > > 4
> > > > > > > bit
> > > > > > > case.
> > > > > > > 
> > > > > > > > We need new calculation method for 4bit block
> > > > > > > > protection
> > > > > > > > and
> > > > > > > > for
> > > > > > > > making
> > > > > > > > it more generic, I choose n_sectors.
> > > > > > > > 
> > > > > > > > On all the flashes I checked, n_sectors is proper value
> > > > > > > > for
> > > > > > > > getting
> > > > > > > > block protected portion.
> > > > > > > > 
> > > > > > > > 		density	portion	n_sectors
> > > > > > > > W25M512JV	64MB	1/512	512
> > > > > > > > N25Q128A	16MB	1/256	256
> > > > > > > > N25Q512A	64MB	1/1024	1024
> > > > > > > > MT25QL02GCBB	256MB	1/4096	4096
> > > > > > > 
> > > > > > > The rules above apply to these flashes, too. Could you
> > > > > > > double
> > > > > > > check
> > > > > > > that?
> > > > > > > 
> > > > > > > -michael
> > > > > > > 
> > > > > > > > 
> > > > > > > > > > +		val = val << SR_BP_SHIFT;
> > > > > > > > > > +
> > > > > > > > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
> > > > > > > > > > +			val = (val & ~BIT(5)) | BIT(6);
> > > > > > > > > > +	} else {
> > > > > > > > > > +		val = mask - (pow << SR_BP_SHIFT);
> > > > > > > > > > +	}
> > > > > > > > > > +
> > > > > > > > > >  	if (val & ~mask)
> > > > > > > > > >  		return -EINVAL;
> > > > > > > > > >  	/* Don't "lock" with no region! */
> > > > > > > > > > @@ -1983,6 +2057,13 @@ static int stm_unlock(struct
> > > > > > > > > > spi_nor
> > > > > > > > > > *nor,
> > > > > > > > > > loff_t ofs, uint64_t len)
> > > > > > > > > > 
> > > > > > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> > > > > > > > > >  		tb_mask = SR_TB_BIT6;
> > > > > > > > > > +
> > > > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > > > > > +		if (nor->flags &
> > > > > > > > > > SNOR_F_HAS_SR_BP3_BIT6)
> > > > > > > > > > +			mask = mask | SR_BP3_BIT6;
> > > > > > > > > > +		else
> > > > > > > > > > +			mask = mask | SR_BP3_BIT5;
> > > > > > > > > > +	}
> > > > > > > > > >  	/*
> > > > > > > > > >  	 * Need largest pow such that:
> > > > > > > > > >  	 *
> > > > > > > > > > @@ -1995,13 +2076,20 @@ static int
> > > > > > > > > > stm_unlock(struct
> > > > > > > > > > spi_nor
> > > > > > > > > > *nor,
> > > > > > > > > > loff_t ofs, uint64_t len)
> > > > > > > > > >  	pow = ilog2(mtd->size) -
> > > > > > > > > > order_base_2(lock_len);
> > > > > > > > > >  	if (lock_len == 0) {
> > > > > > > > > >  		val = 0; /* fully unlocked */
> > > > > > > > > > +	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > > > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
> > > > > > > > > > +		val = val << SR_BP_SHIFT;
> > > > > > > > > > +
> > > > > > > > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
> > > > > > > > > > +			val = (val & ~BIT(5)) | BIT(6);
> > > > > > > > > >  	} else {
> > > > > > > > > >  		val = mask - (pow << SR_BP_SHIFT);
> > > > > > > > > > -		/* Some power-of-two sizes are not
> > > > > > > > > > supported */
> > > > > > > > > > -		if (val & ~mask)
> > > > > > > > > > -			return -EINVAL;
> > > > > > > > > >  	}
> > > > > > > > > > 
> > > > > > > > > > +	/* Some power-of-two sizes are not supported */
> > > > > > > > > > +	if (val & ~mask)
> > > > > > > > > > +		return -EINVAL;
> > > > > > > > > > +
> > > > > > > > > >  	status_new = (status_old & ~mask & ~tb_mask) |
> > > > > > > > > > val;
> > > > > > > > > > 
> > > > > > > > > >  	/* Don't protect status register if we're fully
> > > > > > > > > > unlocked */
> > > > > > > > > > @@ -4736,6 +4824,7 @@ static void
> > > > > > > > > > spi_nor_info_init_params(struct
> > > > > > > > > > spi_nor *nor)
> > > > > > > > > >  	/* Set SPI NOR sizes. */
> > > > > > > > > >  	params->size = (u64)info->sector_size * info-
> > > > > > > > > > > n_sectors;
> > > > > > > > > > 
> > > > > > > > > >  	params->page_size = info->page_size;
> > > > > > > > > > +	params->n_sectors = info->n_sectors;
> > > > > > > > > > 
> > > > > > > > > >  	if (!(info->flags & SPI_NOR_NO_FR)) {
> > > > > > > > > >  		/* Default to Fast Read for DT and non-
> > > > > > > > > > DT
> > > > > > > > > > platform
> > > > > > > > > > devices. */
> > > > > > > > > > @@ -5192,6 +5281,11 @@ int spi_nor_scan(struct
> > > > > > > > > > spi_nor
> > > > > > > > > > *nor,
> > > > > > > > > > const
> > > > > > > > > > char *name,
> > > > > > > > > >  		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
> > > > > > > > > >  	if (info->flags & USE_CLSR)
> > > > > > > > > >  		nor->flags |= SNOR_F_USE_CLSR;
> > > > > > > > > > +	if (info->flags & SPI_NOR_HAS_BP3) {
> > > > > > > > > > +		nor->flags |= SNOR_F_HAS_SR_BP3;
> > > > > > > > > > +		if (info->flags & SPI_NOR_BP3_SR_BIT6)
> > > > > > > > > > +			nor->flags |=
> > > > > > > > > > SNOR_F_HAS_SR_BP3_BIT6;
> > > > > > > > > > +	}
> > > > > > > > > > 
> > > > > > > > > >  	if (info->flags & SPI_NOR_NO_ERASE)
> > > > > > > > > >  		mtd->flags |= MTD_NO_ERASE;
> > > > > > > > > > @@ -5199,6 +5293,7 @@ int spi_nor_scan(struct
> > > > > > > > > > spi_nor
> > > > > > > > > > *nor,
> > > > > > > > > > const
> > > > > > > > > > char *name,
> > > > > > > > > >  	mtd->dev.parent = dev;
> > > > > > > > > >  	nor->page_size = params->page_size;
> > > > > > > > > >  	mtd->writebufsize = nor->page_size;
> > > > > > > > > > +	nor->n_sectors = params->n_sectors;
> > > > > > > > > > 
> > > > > > > > > >  	if (of_property_read_bool(np, "broken-flash-
> > > > > > > > > > reset"))
> > > > > > > > > >  		nor->flags |= SNOR_F_BROKEN_RESET;
> > > > > > > > > > diff --git a/include/linux/mtd/spi-nor.h
> > > > > > > > > > b/include/linux/mtd/spi-
> > > > > > > > > > nor.h
> > > > > > > > > > index 541c06d042e8..92d550501daf 100644
> > > > > > > > > > --- a/include/linux/mtd/spi-nor.h
> > > > > > > > > > +++ b/include/linux/mtd/spi-nor.h
> > > > > > > > > > @@ -129,7 +129,9 @@
> > > > > > > > > >  #define SR_BP1			BIT(3)	/*
> > > > > > > > > > Block
> > > > > > > > > > protect 1
> > > > > > > > > > */
> > > > > > > > > >  #define SR_BP2			BIT(4)	/*
> > > > > > > > > > Block
> > > > > > > > > > protect 2
> > > > > > > > > > */
> > > > > > > > > >  #define SR_TB_BIT5		BIT(5)	/*
> > > > > > > > > > Top/Bottom
> > > > > > > > > > protect
> > > > > > > > > > */
> > > > > > > > > > +#define SR_BP3_BIT5		BIT(5)	/*
> > > > > > > > > > Block
> > > > > > > > > > protect 3
> > > > > > > > > > */
> > > > > > > > > 
> > > > > > > > > maybe just name it SR_BP3? would also be more
> > > > > > > > > consistent
> > > > > > > > > with
> > > > > > > > > the
> > > > > > > > > proposal
> > > > > > > > > above.
> > > > > > > > > 
> > > > > > > > > >  #define SR_TB_BIT6		BIT(6)	/*
> > > > > > > > > > Top/Bottom
> > > > > > > > > > protect
> > > > > > > > > > */
> > > > > > > > > > +#define SR_BP3_BIT6		BIT(6)	/*
> > > > > > > > > > Block
> > > > > > > > > > protect 3
> > > > > > > > > > */
> > > > > > > > > >  #define SR_SRWD			BIT(7)	/*
> > > > > > > > > > SR
> > > > > > > > > > write
> > > > > > > > > > protect
> > > > > > > > > > */
> > > > > > > > > >  /* Spansion/Cypress specific status bits */
> > > > > > > > > >  #define SR_E_ERR		BIT(5)
> > > > > > > > > > @@ -248,6 +250,8 @@ enum spi_nor_option_flags {
> > > > > > > > > >  	SNOR_F_HAS_16BIT_SR	= BIT(9),
> > > > > > > > > >  	SNOR_F_NO_READ_CR	= BIT(10),
> > > > > > > > > >  	SNOR_F_HAS_SR_TB_BIT6	= BIT(11),
> > > > > > > > > > +	SNOR_F_HAS_SR_BP3	= BIT(12),
> > > > > > > > > > +	SNOR_F_HAS_SR_BP3_BIT6	= BIT(13),
> > > > > > > > > > 
> > > > > > > > > >  };
> > > > > > > > > > 
> > > > > > > > > > @@ -519,6 +523,7 @@ struct spi_nor_locking_ops {
> > > > > > > > > >   *
> > > > > > > > > >   * @size:		the flash memory density in
> > > > > > > > > > bytes.
> > > > > > > > > >   * @page_size:		the page size of the
> > > > > > > > > > SPI NOR
> > > > > > > > > > flash
> > > > > > > > > > memory.
> > > > > > > > > > + * @n_sectors:		number of sectors
> > > > > > > > > >   * @hwcaps:		describes the read and
> > > > > > > > > > page
> > > > > > > > > > program
> > > > > > > > > > hardware
> > > > > > > > > >   *			capabilities.
> > > > > > > > > >   * @reads:		read capabilities ordered by
> > > > > > > > > > priority:
> > > > > > > > > > the
> > > > > > > > > > higher index
> > > > > > > > > > @@ -541,6 +546,7 @@ struct spi_nor_locking_ops {
> > > > > > > > > >  struct spi_nor_flash_parameter {
> > > > > > > > > >  	u64				size;
> > > > > > > > > >  	u32				page_size;
> > > > > > > > > > +	u16				n_sectors;
> > > > > > > > > > 
> > > > > > > > > >  	struct spi_nor_hwcaps		hwcaps;
> > > > > > > > > >  	struct spi_nor_read_command	reads[SNOR_CMD_
> > > > > > > > > > READ_MAX
> > > > > > > > > > ];
> > > > > > > > > > @@ -573,6 +579,7 @@ struct flash_info;
> > > > > > > > > >   * @bouncebuf_size:	size of the bounce
> > > > > > > > > > buffer
> > > > > > > > > >   * @info:		spi-nor part JDEC MFR id and
> > > > > > > > > > other info
> > > > > > > > > >   * @page_size:		the page size of the
> > > > > > > > > > SPI NOR
> > > > > > > > > > + * @n_sector:		number of sectors
> > > > > > > > > >   * @addr_width:		number of address bytes
> > > > > > > > > >   * @erase_opcode:	the opcode for erasing a sector
> > > > > > > > > >   * @read_opcode:	the read opcode
> > > > > > > > > > @@ -599,6 +606,7 @@ struct spi_nor {
> > > > > > > > > >  	size_t			bouncebuf_size;
> > > > > > > > > >  	const struct flash_info	*info;
> > > > > > > > > >  	u32			page_size;
> > > > > > > > > > +	u16			n_sectors;
> > > > > > > > > >  	u8			addr_width;
> > > > > > > > > >  	u8			erase_opcode;
> > > > > > > > > >  	u8			read_opcode;
> > > > > > > > > > --
> > > > > > > > > > 2.17.1
> > > > > > > > > > 
> > > > > > > > > > 
> > > > > > > > > > ___________________________________________________
> > > > > > > > > > ___
> > > > > > > > > > Linux MTD discussion mailing list
> > > > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > 
> > > > > > 
> > > > 
> > > > 
> > 
> > 
https://protect2.fireeye.com/url?k=06b6dd5d-5b7d5a63-06b75612-0cc47a31309a-83164929001f7741&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
> > > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > 
> > > > > > > 
> > > > > 
> > > > > 
> > > 
> > > 
> > 
> > Thanks,
> > Jungseung Lee
> 

Thanks,
Jungseung Lee


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Vignesh Raghavendra]

Hi Michael,

On 30/01/20 1:47 pm, Jungseung Lee wrote:
[...]

>>>>>>>>>  	/*
>>>>>>>>>  	 * Need smallest pow such that:
>>>>>>>>>  	 *
>>>>>>>>> @@ -1908,7 +1972,17 @@ static int stm_lock(struct
>>>>>>>>> spi_nor
>>>>>>>>> *nor,
>>>>>>>>> loff_t ofs, uint64_t len)
>>>>>>>>>  	 *   pow = ceil(log2(size / len)) = log2(size)
>>>>>>>>> -
>>>>>>>>> floor(log2(len))
>>>>>>>>>  	 */
>>>>>>>>>  	pow = ilog2(mtd->size) - ilog2(lock_len);
>>>>>>>>> -	val = mask - (pow << SR_BP_SHIFT);
>>>>>>>>> +
>>>>>>>>> +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>>>>>>>>> +		val = ilog2(nor->n_sectors) + 1 - pow;
>>>>>>>>
>>>>>>>> Why do you use a new calculation here? As far as I can
>>>>>>>> see,
>>>>>>>> the
>>>>>>>> method is
>>>>>>>> the same except that is has one bit more. That also
>>>>>>>> raises
>>>>>>>> the
>>>>>>>> question why
>>>>>>>> n_sectors is now needed?
>>>>>>>>

Flash devices have variable sector size, 64KB, 128KB or 256KB... While
mapping of number of sectors locked to BP bits is dependent on rules 1
to 3 you mentioned below, the size or area of flash protected depends on
sector size.

So, the current formula in spi-nor.c (ignoring TB and other boilerplate):

pow = ilog2(mtd->size) - ilog2(lock_len);
val = mask - (pow << shift);

This works only for devices with 64KB sector size as 8MB flash with 64KB
sector size would have 128 sectors (BP0-2 => 0b111 => 2^7).

A more generic formula would be:

Find n where 2^(n - 1) = len/sector-size
OR 2^ (n - 1) = len * n_sectors / mtd->size

Which solves to:

pow = ilog2(mtd->size) - ilog2(lock_len);
val = ilog2(nor->n_sectors) + 1 - pow;

I see this is what Jungseung has tried to implement here.  Please
correct me if I got this wrong.

This, combined with point (3) below should provide a generic
implementation that should support a wide variety of flashes.

Of course, there are always exceptions and they need to be handled using
custom hooks.

I don't have the patch that you shared with Jungseung. I would greatly
appreciate, if you and Jungseung could work on patch with above logic as
well as fixes to handle overflow case?

Thanks a lot Jungseung and Michael for your efforts!

Regards
Vignesh

>>>>>>>> Can't we just initialize the mask with
>>>>>>>>
>>>>>>>> mask = SR_BP2 | SR_BP1 | SR_BP0;
>>>>>>>> if (nor->flags & SNOR_F_HAS_SR_BP3)
>>>>>>>>     mask |= SR_BP3_BIT5;
>>>>>>>>
>>>>>>>> do the calculation and checks and then move the
>>>>>>>> SR_BP3_BIT5
>>>>>>>> to
>>>>>>>> SR_BP3_BIT6
>>>>>>>> if SNOR_F_HAS_SR_BP3_BIT6 is set.
>>>>>>>>
>>>>>>>
>>>>>>> For most of flashes that supporting BP0-2, the smallest
>>>>>>> protected
>>>>>>> portion is fixed as 1/64
>>>>>>> and it can be properly handled by existing
>>>>>>> calculation. (Actually it's not fully generic, see flashes
>>>>>>> like
>>>>>>> w25q40bw or m25p80. Of course, it doesn't have
>>>>>>> SPI_NOR_HAS_LOCK
>>>>>>> flag
>>>>>>> even though it has BP0-2 bit in SR)
>>>>>>
>>>>>> No. The rules are always the same wether there are three or
>>>>>> four
>>>>>> BP
>>>>>> bits (the example in stm_lock() has not enough information on
>>>>>> this):
>>>>>>
>>>>>> (1) the first setting (besides 0) protects one sector. The
>>>>>> second
>>>>>>      protects 2, the third 4 and so on. eg 2^N
>>>>>> (2) the last setting is _always_ protect all, just like the
>>>>>> '0'
>>>>>> setting
>>>>>>      is always protect none.
>>>>>> (3) if there is an overflow because there are no more free
>>>>>> slots
>>>>>> for
>>>>>>      further settings (for 3 bits with flashes > 32MBit, for
>>>>>> 4
>>>>>>      bits if should be flashes > 16GBit), the first entry
>>>>>> will be
>>>>>>      discarded (eg the very first is the "just one sector"
>>>>>> entry).
>>>>>>
>>>>>> This is true for all flashes which uses this kind of setting,
>>>>>> have a
>>>>>> look at the m25p80 or w25q40bw, these are no exception. It is
>>>>>> just
>>>>>> the
>>>>>> notation "lower 1/64" which is only true for flashes which
>>>>>> either
>>>>>> overflows in (3) or fill all entries (eg. with 3bits that
>>>>>> would
>>>>>> be
>>>>>> the
>>>>>> 32Mbit version).
>>>>>>
>>>>>
>>>>> Looks like you noticed that we need new calculation method that
>>>>> would
>>>>> be based on n_sectors :).
>>>>
>>>> No it will work without that (if I'm not mistaken). Give me some
>>>> time
>>>> and I'll post a patch.
>>>
>>> No, it must be based on n_sectors. To make 4bit block protection
>>> more
>>> generic, the lock sector size must NOT fixed as 64KB (as can be
>>> checked
>>> from your patch). See "mt35xu02g" and check the protected area and
>>> number of sectors from it's datasheet.
>>
>> There is no public datasheet as far as I can see. And yes, actually
>> n_sectors is my "mtd-size / sector_size". But I don't see how
>> n_sectors
>> would help if the sector size changes.
>>
>>> The rule you mentioned "the first setting (besides 0) protects one
>>> sector" is alawys true for *4bit* block protection. That's why I
>>> choose
>>> n_sectors for new calculation.
>>
>> And how does flashes behave once all the free slots are full? It was
>> the
>> same with the 3bit flashes, they only overflowed with "newer"/bigger
>> flashes.
>>
>>
>>>>
>>>>> Rule (1) is NOT true for some flashes
>>>>> supporting BP0-2 and that's why I said that smallest protected
>>>>> portion
>>>>> is fixed as '1/64' for these flashes.
>>>>
>>>> No, you have to apply rule (3). (1) is only the starting point.
>>>> It
>>>> is
>>>> kind
>>>> of a sliding window.
>>>>
>>>>> See this one.
>>>>>
>>>>> W25Q20EW	256KB	1/4 ... = 64KB		BP2
>>>>> W25Q128JV	16MB	1/64 ... = 256KB	BP2 <--
>>>>> S25FL132K	4MB	1/64 ... = 64KB		BP2 <--
>>>>> S25FL164K	8MB
>>>>> 1/64 ... = 128KB	BP2 <--
>>>>
>>>> All these flashes need (3) to be applied, thus (1) doesn't apply
>>>> anymore.
>>>>
>>>> Let me give you an example for the 64MBit case, the settings
>>>> would
>>>> be:
>>>>
>>>> 0 sectors (corresponds to protect none)
>>>> 1 sector
>>>> 2 sectors
>>>> 4 sectors
>>>> 8 sectors
>>>> 16 sectors
>>>> 32 sectors
>>>> 64 sectors
>>>> 128 sectors (corresponds to protect all)
>>>>
>>>> Unfortunately, we have only 8 slots (because 3 BP bits),
>>>> therefore
>>>> we
>>>> have
>>>> to discard some setting. According to rule (2) 0 is always
>>>> "protect
>>>> none"
>>>> and 7 is always "protect all". Thus we have 6 settings left.
>>>> According
>>>> to
>>>> rule (3) we discard the first ones. In this case, this is the "1
>>>> sector"
>>>> setting. Thus we end up with the following possible settings:
>>>>
>>>> 0 sectors (corresponds to protect none)
>>>> 2 sectors
>>>> 4 sectors
>>>> 8 sectors
>>>> 16 sectors
>>>> 32 sectors
>>>> 64 sectors
>>>> 128 sectors (corresponds to protect all)
>>>>
>>>> If you have a 128Mbit flash, the next setting that would be
>>>> discarded
>>>> is
>>>> "2 sectors". Thus it would start with:
>>>>
>>>> 0 sectors (corresponds to protect none)
>>>> 4 sectors
>>>> [..]
>>>> 256 sectors (corresponds to protect all)
>>>>
>>>>
>>>> Another example W25Q20EW, following possible settings:
>>>>
>>>> 0 sectors (corresponds to protect none)
>>>> 1 sector
>>>> 2 sectors
>>>> 4 sectors (corresponds to protect all)
>>>>
>>>> We now have less settings then our 8 possible slots. So this is
>>>> where
>>>> rule (1) applies, because according to that the "1 sector"
>>>> setting is
>>>> the first possible setting besides 0.
>>>>
>>>> And this also applies to the 4 bit protection bits.
>>>>
>>>>
>>>>
>>>>> W25Q256JV	32MB	1/512 ... =
>>>>> 64KB	BP3
>>>>> S25FL128L	16MB	1/256 ... = 64KB	BP3
>>>>> S25FL256L	32MB	1/512 ... = 64KB	BP3
>>>>>
>>>>> In current BP implementation, block protection is just working
>>>>> for
>>>>> some
>>>>> flashes that has smallest protected portion as '1/64'.
>>>>
>>>> No its currently working for all except flashes smaller than
>>>> 32Mbit.
>>>
>>> No. Not working for flashes supporting 4bit block protection.
>>>
>>>> Applied to the 4 bits, this would mean "it works for all except
>>>> flashes
>>>> smaller than 8Gbit" which are practially all. As I said, this is
>>>> a
>>>> bug
>>>> and once this bug is fixed, there should be no difference between
>>>> 3
>>>> and 4 bits.
>>>>
>>>> -michael
>>>>
>>>
>>> The exact fact is that locks operate in two different ways
>>> according to
>>> flash model.
>>>
>>> (1) the smallest protected portion is fixed.
>>> 	for BP0-2 : 1/64
>>> 	for BP0-1 : 1/4
>>
>> As mentioned earlier, the ratio nomenclature is missleading and only 
>> valid if the table is completely filled up.
>>
>> Take a flash with 128kB and three BP bits (or even only two BP
>> bits). 
>> The
>> smallest portion will be 64kB (which is one sector and not 1/64).
>>
>> Thus the smallest portion is always one sector, unless the table is
>> overflowing, then the smallest will settle to 1/4 (for two), 1/64
>> (for 
>> three)
>> and 1/16384 (for four bits).
>>
>>> (2) the smallest protected portion is inversely propotional with
>>> number
>>> of sectors.
>>>
>>> For the flashes supporting 3bit block protection, (1) and (2) are
>>> mixed
>>> and used. But all the flashes supporting 4bit block protection
>>> listed
>>> on spi-nor.c, only (2) is used.
>>
>> It is not mixed it just depends on the flash size (and the number of
>> protection bits).
>>
> 
> It is mixed. Let's compare "en25qh128" from EON with "w25q128jv" from
> Winbond. They have the same capacity(128MBit) and also supporting 3bit
> block protection. (Note that the named BP3 bit of "en25qh128" is
> working exactly same with T/B bit.)
> 
> "en25qh128" is following (2) and "w25q128jv" is following (1). It seems
> impossible to distinguish them by the flash size or the number of
> protection bits. 
> 
> I also still have no idea how your three rules are applicable for 2bit
> block protection (bp0-1).
> 
>>> Each method requires each formula. I have no idea how to handle it
>>> with
>>> one formula (probably adding number of exceptional handling?)
>>> without
>>> any sectional flag. "w25q128jv(bp0-2)" is following (1) and
>>> "n25q128a(bp0-3)" is following (2).
>>
>> Well one uses three BPs the other four, and they all follow the
>> three 
>> rules
>> above. Did you try my patch? Because I've (at least in userspace)
>> tested
>> it with 4 bits and got the correct results.
>>
>> And yes, its actually two different formulas, but not for 3 and 4
>> bits like in your patch. 
> 
> The title of my patch is "add 4bit block protection support". I just
> let 3bit block protection as it is, I've implemented something what I
> could check. As I mentioned, for all the flashes supporting 4bit block
> protection only (2) is used and this patch has been implemented based
> on this fact.
> 
>> It is rather one formula (A) for flashes which don't 
>> exhaust
>> the BP bits (eg. for 3 bits this would be flashes <= 16Mbit and for
>> 4 
>> bits
>> this would be for flashes <=8Gbit) and one (B) for the flashes where 
>> every
>> BP bit combination is used. What is at the moment in the kernel is
>> the
>> second one, thus it will fail for flashes <= 16Mbit and 3 BP bits;
>> and 
>> it
>> also fails for all flashes with 4 bits. My patch does a fixup on (B)
>> to
>> match the results of (A), because doing this is less invasive; and as
>> mentioned in the patch annex, might also be rewritten for a better
>> understanding.
> 
> I've never seen spi flashes greater than 8Gbit (maybe you also), so I
> am not sure whether the three rules are applicable to 4 bit block
> protection. Even the three rules doesn't seem to be general enough for
> 3bit or 2bit block protection.
> 
>>
>>
>> -michael
>>
>>>
>>>>>
>>>>> We need new fomula based on n_sectors for BP3 at least.
>>>>
>>>> No they are the same, but yes there is a bug in the current
>>>> implementation.
>>>>
>>>> -michael
>>>>
>>>>>
>>>>>> So for the 3 bit case the following flashes are border cases:
>>>>>>   - 16mbit (less settings than slots)
>>>>>>   - 32mbit (number of settings and free slots match)
>>>>>>   - 64mbit (more settings than slots, first setting is
>>>>>> discarded)
>>>>>>
>>>>>> That being said, I suspect all the 16mbit flashes (and below)
>>>>>> which
>>>>>> have
>>>>>> the _LOCK bit set are broken, because the entries has to be
>>>>>> shifted.
>>>>>> I'll
>>>>>> look into that later. This is the same "issue" you have with
>>>>>> the
>>>>>> 4
>>>>>> bits.
>>>>>> So if this is fixed, you should not need another formula for
>>>>>> the
>>>>>> 4
>>>>>> bit
>>>>>> case.
>>>>>>
>>>>>>> We need new calculation method for 4bit block protection
>>>>>>> and
>>>>>>> for
>>>>>>> making
>>>>>>> it more generic, I choose n_sectors.
>>>>>>>
>>>>>>> On all the flashes I checked, n_sectors is proper value for
>>>>>>> getting
>>>>>>> block protected portion.
>>>>>>>
>>>>>>> 		density	portion	n_sectors
>>>>>>> W25M512JV	64MB	1/512	512
>>>>>>> N25Q128A	16MB	1/256	256
>>>>>>> N25Q512A	64MB	1/1024	1024
>>>>>>> MT25QL02GCBB	256MB	1/4096	4096
>>>>>>
>>>>>> The rules above apply to these flashes, too. Could you double
>>>>>> check
>>>>>> that?
>>>>>>
>>>>>> -michael
>>>>>>
>>>>>>>
>>>>>>>>> +		val = val << SR_BP_SHIFT;
>>>>>>>>> +
>>>>>>>>> +		if (val & BIT(5) && mask & SR_BP3_BIT6)
>>>>>>>>> +			val = (val & ~BIT(5)) | BIT(6);
>>>>>>>>> +	} else {
>>>>>>>>> +		val = mask - (pow << SR_BP_SHIFT);
>>>>>>>>> +	}
>>>>>>>>> +
>>>>>>>>>  	if (val & ~mask)
>>>>>>>>>  		return -EINVAL;
>>>>>>>>>  	/* Don't "lock" with no region! */
>>>>>>>>> @@ -1983,6 +2057,13 @@ static int stm_unlock(struct
>>>>>>>>> spi_nor
>>>>>>>>> *nor,
>>>>>>>>> loff_t ofs, uint64_t len)
>>>>>>>>>
>>>>>>>>>  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>>>>>>>>>  		tb_mask = SR_TB_BIT6;
>>>>>>>>> +
>>>>>>>>> +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>>>>>>>>> +		if (nor->flags &
>>>>>>>>> SNOR_F_HAS_SR_BP3_BIT6)
>>>>>>>>> +			mask = mask | SR_BP3_BIT6;
>>>>>>>>> +		else
>>>>>>>>> +			mask = mask | SR_BP3_BIT5;
>>>>>>>>> +	}
>>>>>>>>>  	/*
>>>>>>>>>  	 * Need largest pow such that:
>>>>>>>>>  	 *
>>>>>>>>> @@ -1995,13 +2076,20 @@ static int stm_unlock(struct
>>>>>>>>> spi_nor
>>>>>>>>> *nor,
>>>>>>>>> loff_t ofs, uint64_t len)
>>>>>>>>>  	pow = ilog2(mtd->size) -
>>>>>>>>> order_base_2(lock_len);
>>>>>>>>>  	if (lock_len == 0) {
>>>>>>>>>  		val = 0; /* fully unlocked */
>>>>>>>>> +	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
>>>>>>>>> +		val = ilog2(nor->n_sectors) + 1 - pow;
>>>>>>>>> +		val = val << SR_BP_SHIFT;
>>>>>>>>> +
>>>>>>>>> +		if (val & BIT(5) && mask & SR_BP3_BIT6)
>>>>>>>>> +			val = (val & ~BIT(5)) | BIT(6);
>>>>>>>>>  	} else {
>>>>>>>>>  		val = mask - (pow << SR_BP_SHIFT);
>>>>>>>>> -		/* Some power-of-two sizes are not
>>>>>>>>> supported */
>>>>>>>>> -		if (val & ~mask)
>>>>>>>>> -			return -EINVAL;
>>>>>>>>>  	}
>>>>>>>>>
>>>>>>>>> +	/* Some power-of-two sizes are not supported */
>>>>>>>>> +	if (val & ~mask)
>>>>>>>>> +		return -EINVAL;
>>>>>>>>> +
>>>>>>>>>  	status_new = (status_old & ~mask & ~tb_mask) |
>>>>>>>>> val;
>>>>>>>>>
>>>>>>>>>  	/* Don't protect status register if we're fully
>>>>>>>>> unlocked */
>>>>>>>>> @@ -4736,6 +4824,7 @@ static void
>>>>>>>>> spi_nor_info_init_params(struct
>>>>>>>>> spi_nor *nor)
>>>>>>>>>  	/* Set SPI NOR sizes. */
>>>>>>>>>  	params->size = (u64)info->sector_size * info-
>>>>>>>>>> n_sectors;
>>>>>>>>>
>>>>>>>>>  	params->page_size = info->page_size;
>>>>>>>>> +	params->n_sectors = info->n_sectors;
>>>>>>>>>
>>>>>>>>>  	if (!(info->flags & SPI_NOR_NO_FR)) {
>>>>>>>>>  		/* Default to Fast Read for DT and non-
>>>>>>>>> DT
>>>>>>>>> platform
>>>>>>>>> devices. */
>>>>>>>>> @@ -5192,6 +5281,11 @@ int spi_nor_scan(struct spi_nor
>>>>>>>>> *nor,
>>>>>>>>> const
>>>>>>>>> char *name,
>>>>>>>>>  		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
>>>>>>>>>  	if (info->flags & USE_CLSR)
>>>>>>>>>  		nor->flags |= SNOR_F_USE_CLSR;
>>>>>>>>> +	if (info->flags & SPI_NOR_HAS_BP3) {
>>>>>>>>> +		nor->flags |= SNOR_F_HAS_SR_BP3;
>>>>>>>>> +		if (info->flags & SPI_NOR_BP3_SR_BIT6)
>>>>>>>>> +			nor->flags |=
>>>>>>>>> SNOR_F_HAS_SR_BP3_BIT6;
>>>>>>>>> +	}
>>>>>>>>>
>>>>>>>>>  	if (info->flags & SPI_NOR_NO_ERASE)
>>>>>>>>>  		mtd->flags |= MTD_NO_ERASE;
>>>>>>>>> @@ -5199,6 +5293,7 @@ int spi_nor_scan(struct spi_nor
>>>>>>>>> *nor,
>>>>>>>>> const
>>>>>>>>> char *name,
>>>>>>>>>  	mtd->dev.parent = dev;
>>>>>>>>>  	nor->page_size = params->page_size;
>>>>>>>>>  	mtd->writebufsize = nor->page_size;
>>>>>>>>> +	nor->n_sectors = params->n_sectors;
>>>>>>>>>
>>>>>>>>>  	if (of_property_read_bool(np, "broken-flash-
>>>>>>>>> reset"))
>>>>>>>>>  		nor->flags |= SNOR_F_BROKEN_RESET;
>>>>>>>>> diff --git a/include/linux/mtd/spi-nor.h
>>>>>>>>> b/include/linux/mtd/spi-
>>>>>>>>> nor.h
>>>>>>>>> index 541c06d042e8..92d550501daf 100644
>>>>>>>>> --- a/include/linux/mtd/spi-nor.h
>>>>>>>>> +++ b/include/linux/mtd/spi-nor.h
>>>>>>>>> @@ -129,7 +129,9 @@
>>>>>>>>>  #define SR_BP1			BIT(3)	/* Block
>>>>>>>>> protect 1
>>>>>>>>> */
>>>>>>>>>  #define SR_BP2			BIT(4)	/* Block
>>>>>>>>> protect 2
>>>>>>>>> */
>>>>>>>>>  #define SR_TB_BIT5		BIT(5)	/* Top/Bottom
>>>>>>>>> protect
>>>>>>>>> */
>>>>>>>>> +#define SR_BP3_BIT5		BIT(5)	/* Block
>>>>>>>>> protect 3
>>>>>>>>> */
>>>>>>>>
>>>>>>>> maybe just name it SR_BP3? would also be more consistent
>>>>>>>> with
>>>>>>>> the
>>>>>>>> proposal
>>>>>>>> above.
>>>>>>>>
>>>>>>>>>  #define SR_TB_BIT6		BIT(6)	/* Top/Bottom
>>>>>>>>> protect
>>>>>>>>> */
>>>>>>>>> +#define SR_BP3_BIT6		BIT(6)	/* Block
>>>>>>>>> protect 3
>>>>>>>>> */
>>>>>>>>>  #define SR_SRWD			BIT(7)	/* SR
>>>>>>>>> write
>>>>>>>>> protect
>>>>>>>>> */
>>>>>>>>>  /* Spansion/Cypress specific status bits */
>>>>>>>>>  #define SR_E_ERR		BIT(5)
>>>>>>>>> @@ -248,6 +250,8 @@ enum spi_nor_option_flags {
>>>>>>>>>  	SNOR_F_HAS_16BIT_SR	= BIT(9),
>>>>>>>>>  	SNOR_F_NO_READ_CR	= BIT(10),
>>>>>>>>>  	SNOR_F_HAS_SR_TB_BIT6	= BIT(11),
>>>>>>>>> +	SNOR_F_HAS_SR_BP3	= BIT(12),
>>>>>>>>> +	SNOR_F_HAS_SR_BP3_BIT6	= BIT(13),
>>>>>>>>>
>>>>>>>>>  };
>>>>>>>>>
>>>>>>>>> @@ -519,6 +523,7 @@ struct spi_nor_locking_ops {
>>>>>>>>>   *
>>>>>>>>>   * @size:		the flash memory density in
>>>>>>>>> bytes.
>>>>>>>>>   * @page_size:		the page size of the SPI NOR
>>>>>>>>> flash
>>>>>>>>> memory.
>>>>>>>>> + * @n_sectors:		number of sectors
>>>>>>>>>   * @hwcaps:		describes the read and page
>>>>>>>>> program
>>>>>>>>> hardware
>>>>>>>>>   *			capabilities.
>>>>>>>>>   * @reads:		read capabilities ordered by
>>>>>>>>> priority:
>>>>>>>>> the
>>>>>>>>> higher index
>>>>>>>>> @@ -541,6 +546,7 @@ struct spi_nor_locking_ops {
>>>>>>>>>  struct spi_nor_flash_parameter {
>>>>>>>>>  	u64				size;
>>>>>>>>>  	u32				page_size;
>>>>>>>>> +	u16				n_sectors;
>>>>>>>>>
>>>>>>>>>  	struct spi_nor_hwcaps		hwcaps;
>>>>>>>>>  	struct spi_nor_read_command	reads[SNOR_CMD_
>>>>>>>>> READ_MAX
>>>>>>>>> ];
>>>>>>>>> @@ -573,6 +579,7 @@ struct flash_info;
>>>>>>>>>   * @bouncebuf_size:	size of the bounce buffer
>>>>>>>>>   * @info:		spi-nor part JDEC MFR id and
>>>>>>>>> other info
>>>>>>>>>   * @page_size:		the page size of the SPI NOR
>>>>>>>>> + * @n_sector:		number of sectors
>>>>>>>>>   * @addr_width:		number of address bytes
>>>>>>>>>   * @erase_opcode:	the opcode for erasing a sector
>>>>>>>>>   * @read_opcode:	the read opcode
>>>>>>>>> @@ -599,6 +606,7 @@ struct spi_nor {
>>>>>>>>>  	size_t			bouncebuf_size;
>>>>>>>>>  	const struct flash_info	*info;
>>>>>>>>>  	u32			page_size;
>>>>>>>>> +	u16			n_sectors;
>>>>>>>>>  	u8			addr_width;
>>>>>>>>>  	u8			erase_opcode;
>>>>>>>>>  	u8			read_opcode;
>>>>>>>>> --
>>>>>>>>> 2.17.1
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> ______________________________________________________
>>>>>>>>> Linux MTD discussion mailing list
>>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>
>>>>>
>>>
>>>
> https://protect2.fireeye.com/url?k=06b6dd5d-5b7d5a63-06b75612-0cc47a31309a-83164929001f7741&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>
>>>>>>
>>>>
>>>>
>>
>>
> 
> Thanks,
> Jungseung Lee
> 

-- 
Regards
Vignesh

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[SPAM] Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Am 2020-02-03 14:56, schrieb Vignesh Raghavendra:
> Hi Michael,
> 
> On 30/01/20 1:47 pm, Jungseung Lee wrote:
> [...]
> 
>>>>>>>>>>  	/*
>>>>>>>>>>  	 * Need smallest pow such that:
>>>>>>>>>>  	 *
>>>>>>>>>> @@ -1908,7 +1972,17 @@ static int stm_lock(struct
>>>>>>>>>> spi_nor
>>>>>>>>>> *nor,
>>>>>>>>>> loff_t ofs, uint64_t len)
>>>>>>>>>>  	 *   pow = ceil(log2(size / len)) = log2(size)
>>>>>>>>>> -
>>>>>>>>>> floor(log2(len))
>>>>>>>>>>  	 */
>>>>>>>>>>  	pow = ilog2(mtd->size) - ilog2(lock_len);
>>>>>>>>>> -	val = mask - (pow << SR_BP_SHIFT);
>>>>>>>>>> +
>>>>>>>>>> +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>>>>>>>>>> +		val = ilog2(nor->n_sectors) + 1 - pow;
>>>>>>>>> 
>>>>>>>>> Why do you use a new calculation here? As far as I can
>>>>>>>>> see,
>>>>>>>>> the
>>>>>>>>> method is
>>>>>>>>> the same except that is has one bit more. That also
>>>>>>>>> raises
>>>>>>>>> the
>>>>>>>>> question why
>>>>>>>>> n_sectors is now needed?
>>>>>>>>> 
> 
> Flash devices have variable sector size, 64KB, 128KB or 256KB... While
> mapping of number of sectors locked to BP bits is dependent on rules 1
> to 3 you mentioned below, the size or area of flash protected depends 
> on
> sector size.

Is there any flash device which has another sector size != 64KiB for the 
BP bits?

> So, the current formula in spi-nor.c (ignoring TB and other 
> boilerplate):
> 
> pow = ilog2(mtd->size) - ilog2(lock_len);
> val = mask - (pow << shift);
> 
> This works only for devices with 64KB sector size as 8MB flash with 
> 64KB
> sector size would have 128 sectors (BP0-2 => 0b111 => 2^7).

It also only works with flashes >= 4MiB. See fix below. And IMHO this is 
exactly
the same "problem" the flashes with 4 BP bits have.

> A more generic formula would be:
> 
> Find n where 2^(n - 1) = len/sector-size
> OR 2^ (n - 1) = len * n_sectors / mtd->size
> 
> Which solves to:
> 
> pow = ilog2(mtd->size) - ilog2(lock_len);
> val = ilog2(nor->n_sectors) + 1 - pow;
> 
> I see this is what Jungseung has tried to implement here.  Please
> correct me if I got this wrong.
> 
> This, combined with point (3) below should provide a generic
> implementation that should support a wide variety of flashes.
> 
> Of course, there are always exceptions and they need to be handled 
> using
> custom hooks.
> 
> I don't have the patch that you shared with Jungseung. I would greatly
> appreciate, if you and Jungseung could work on patch with above logic 
> as
> well as fixes to handle overflow case?

https://lore.kernel.org/linux-mtd/20200123170130.8289-1-michael@walle.cc/

As I said, that should work for both 3 and 4 bits. But be aware that 
this
is an RFC and I've just tested it in in userspace, like the calculation
of the bits and transferred that into the driver. So one would actually
have to test that. But apparently no one had a even applied it.

-michael

> 
> Thanks a lot Jungseung and Michael for your efforts!
> 
> Regards
> Vignesh
> 
>>>>>>>>> Can't we just initialize the mask with
>>>>>>>>> 
>>>>>>>>> mask = SR_BP2 | SR_BP1 | SR_BP0;
>>>>>>>>> if (nor->flags & SNOR_F_HAS_SR_BP3)
>>>>>>>>>     mask |= SR_BP3_BIT5;
>>>>>>>>> 
>>>>>>>>> do the calculation and checks and then move the
>>>>>>>>> SR_BP3_BIT5
>>>>>>>>> to
>>>>>>>>> SR_BP3_BIT6
>>>>>>>>> if SNOR_F_HAS_SR_BP3_BIT6 is set.
>>>>>>>>> 
>>>>>>>> 
>>>>>>>> For most of flashes that supporting BP0-2, the smallest
>>>>>>>> protected
>>>>>>>> portion is fixed as 1/64
>>>>>>>> and it can be properly handled by existing
>>>>>>>> calculation. (Actually it's not fully generic, see flashes
>>>>>>>> like
>>>>>>>> w25q40bw or m25p80. Of course, it doesn't have
>>>>>>>> SPI_NOR_HAS_LOCK
>>>>>>>> flag
>>>>>>>> even though it has BP0-2 bit in SR)
>>>>>>> 
>>>>>>> No. The rules are always the same wether there are three or
>>>>>>> four
>>>>>>> BP
>>>>>>> bits (the example in stm_lock() has not enough information on
>>>>>>> this):
>>>>>>> 
>>>>>>> (1) the first setting (besides 0) protects one sector. The
>>>>>>> second
>>>>>>>      protects 2, the third 4 and so on. eg 2^N
>>>>>>> (2) the last setting is _always_ protect all, just like the
>>>>>>> '0'
>>>>>>> setting
>>>>>>>      is always protect none.
>>>>>>> (3) if there is an overflow because there are no more free
>>>>>>> slots
>>>>>>> for
>>>>>>>      further settings (for 3 bits with flashes > 32MBit, for
>>>>>>> 4
>>>>>>>      bits if should be flashes > 16GBit), the first entry
>>>>>>> will be
>>>>>>>      discarded (eg the very first is the "just one sector"
>>>>>>> entry).
>>>>>>> 
>>>>>>> This is true for all flashes which uses this kind of setting,
>>>>>>> have a
>>>>>>> look at the m25p80 or w25q40bw, these are no exception. It is
>>>>>>> just
>>>>>>> the
>>>>>>> notation "lower 1/64" which is only true for flashes which
>>>>>>> either
>>>>>>> overflows in (3) or fill all entries (eg. with 3bits that
>>>>>>> would
>>>>>>> be
>>>>>>> the
>>>>>>> 32Mbit version).
>>>>>>> 
>>>>>> 
>>>>>> Looks like you noticed that we need new calculation method that
>>>>>> would
>>>>>> be based on n_sectors :).
>>>>> 
>>>>> No it will work without that (if I'm not mistaken). Give me some
>>>>> time
>>>>> and I'll post a patch.
>>>> 
>>>> No, it must be based on n_sectors. To make 4bit block protection
>>>> more
>>>> generic, the lock sector size must NOT fixed as 64KB (as can be
>>>> checked
>>>> from your patch). See "mt35xu02g" and check the protected area and
>>>> number of sectors from it's datasheet.
>>> 
>>> There is no public datasheet as far as I can see. And yes, actually
>>> n_sectors is my "mtd-size / sector_size". But I don't see how
>>> n_sectors
>>> would help if the sector size changes.
>>> 
>>>> The rule you mentioned "the first setting (besides 0) protects one
>>>> sector" is alawys true for *4bit* block protection. That's why I
>>>> choose
>>>> n_sectors for new calculation.
>>> 
>>> And how does flashes behave once all the free slots are full? It was
>>> the
>>> same with the 3bit flashes, they only overflowed with "newer"/bigger
>>> flashes.
>>> 
>>> 
>>>>> 
>>>>>> Rule (1) is NOT true for some flashes
>>>>>> supporting BP0-2 and that's why I said that smallest protected
>>>>>> portion
>>>>>> is fixed as '1/64' for these flashes.
>>>>> 
>>>>> No, you have to apply rule (3). (1) is only the starting point.
>>>>> It
>>>>> is
>>>>> kind
>>>>> of a sliding window.
>>>>> 
>>>>>> See this one.
>>>>>> 
>>>>>> W25Q20EW	256KB	1/4 ... = 64KB		BP2
>>>>>> W25Q128JV	16MB	1/64 ... = 256KB	BP2 <--
>>>>>> S25FL132K	4MB	1/64 ... = 64KB		BP2 <--
>>>>>> S25FL164K	8MB
>>>>>> 1/64 ... = 128KB	BP2 <--
>>>>> 
>>>>> All these flashes need (3) to be applied, thus (1) doesn't apply
>>>>> anymore.
>>>>> 
>>>>> Let me give you an example for the 64MBit case, the settings
>>>>> would
>>>>> be:
>>>>> 
>>>>> 0 sectors (corresponds to protect none)
>>>>> 1 sector
>>>>> 2 sectors
>>>>> 4 sectors
>>>>> 8 sectors
>>>>> 16 sectors
>>>>> 32 sectors
>>>>> 64 sectors
>>>>> 128 sectors (corresponds to protect all)
>>>>> 
>>>>> Unfortunately, we have only 8 slots (because 3 BP bits),
>>>>> therefore
>>>>> we
>>>>> have
>>>>> to discard some setting. According to rule (2) 0 is always
>>>>> "protect
>>>>> none"
>>>>> and 7 is always "protect all". Thus we have 6 settings left.
>>>>> According
>>>>> to
>>>>> rule (3) we discard the first ones. In this case, this is the "1
>>>>> sector"
>>>>> setting. Thus we end up with the following possible settings:
>>>>> 
>>>>> 0 sectors (corresponds to protect none)
>>>>> 2 sectors
>>>>> 4 sectors
>>>>> 8 sectors
>>>>> 16 sectors
>>>>> 32 sectors
>>>>> 64 sectors
>>>>> 128 sectors (corresponds to protect all)
>>>>> 
>>>>> If you have a 128Mbit flash, the next setting that would be
>>>>> discarded
>>>>> is
>>>>> "2 sectors". Thus it would start with:
>>>>> 
>>>>> 0 sectors (corresponds to protect none)
>>>>> 4 sectors
>>>>> [..]
>>>>> 256 sectors (corresponds to protect all)
>>>>> 
>>>>> 
>>>>> Another example W25Q20EW, following possible settings:
>>>>> 
>>>>> 0 sectors (corresponds to protect none)
>>>>> 1 sector
>>>>> 2 sectors
>>>>> 4 sectors (corresponds to protect all)
>>>>> 
>>>>> We now have less settings then our 8 possible slots. So this is
>>>>> where
>>>>> rule (1) applies, because according to that the "1 sector"
>>>>> setting is
>>>>> the first possible setting besides 0.
>>>>> 
>>>>> And this also applies to the 4 bit protection bits.
>>>>> 
>>>>> 
>>>>> 
>>>>>> W25Q256JV	32MB	1/512 ... =
>>>>>> 64KB	BP3
>>>>>> S25FL128L	16MB	1/256 ... = 64KB	BP3
>>>>>> S25FL256L	32MB	1/512 ... = 64KB	BP3
>>>>>> 
>>>>>> In current BP implementation, block protection is just working
>>>>>> for
>>>>>> some
>>>>>> flashes that has smallest protected portion as '1/64'.
>>>>> 
>>>>> No its currently working for all except flashes smaller than
>>>>> 32Mbit.
>>>> 
>>>> No. Not working for flashes supporting 4bit block protection.
>>>> 
>>>>> Applied to the 4 bits, this would mean "it works for all except
>>>>> flashes
>>>>> smaller than 8Gbit" which are practially all. As I said, this is
>>>>> a
>>>>> bug
>>>>> and once this bug is fixed, there should be no difference between
>>>>> 3
>>>>> and 4 bits.
>>>>> 
>>>>> -michael
>>>>> 
>>>> 
>>>> The exact fact is that locks operate in two different ways
>>>> according to
>>>> flash model.
>>>> 
>>>> (1) the smallest protected portion is fixed.
>>>> 	for BP0-2 : 1/64
>>>> 	for BP0-1 : 1/4
>>> 
>>> As mentioned earlier, the ratio nomenclature is missleading and only
>>> valid if the table is completely filled up.
>>> 
>>> Take a flash with 128kB and three BP bits (or even only two BP
>>> bits).
>>> The
>>> smallest portion will be 64kB (which is one sector and not 1/64).
>>> 
>>> Thus the smallest portion is always one sector, unless the table is
>>> overflowing, then the smallest will settle to 1/4 (for two), 1/64
>>> (for
>>> three)
>>> and 1/16384 (for four bits).
>>> 
>>>> (2) the smallest protected portion is inversely propotional with
>>>> number
>>>> of sectors.
>>>> 
>>>> For the flashes supporting 3bit block protection, (1) and (2) are
>>>> mixed
>>>> and used. But all the flashes supporting 4bit block protection
>>>> listed
>>>> on spi-nor.c, only (2) is used.
>>> 
>>> It is not mixed it just depends on the flash size (and the number of
>>> protection bits).
>>> 
>> 
>> It is mixed. Let's compare "en25qh128" from EON with "w25q128jv" from
>> Winbond. They have the same capacity(128MBit) and also supporting 3bit
>> block protection. (Note that the named BP3 bit of "en25qh128" is
>> working exactly same with T/B bit.)
>> 
>> "en25qh128" is following (2) and "w25q128jv" is following (1). It 
>> seems
>> impossible to distinguish them by the flash size or the number of
>> protection bits.
>> 
>> I also still have no idea how your three rules are applicable for 2bit
>> block protection (bp0-1).
>> 
>>>> Each method requires each formula. I have no idea how to handle it
>>>> with
>>>> one formula (probably adding number of exceptional handling?)
>>>> without
>>>> any sectional flag. "w25q128jv(bp0-2)" is following (1) and
>>>> "n25q128a(bp0-3)" is following (2).
>>> 
>>> Well one uses three BPs the other four, and they all follow the
>>> three
>>> rules
>>> above. Did you try my patch? Because I've (at least in userspace)
>>> tested
>>> it with 4 bits and got the correct results.
>>> 
>>> And yes, its actually two different formulas, but not for 3 and 4
>>> bits like in your patch.
>> 
>> The title of my patch is "add 4bit block protection support". I just
>> let 3bit block protection as it is, I've implemented something what I
>> could check. As I mentioned, for all the flashes supporting 4bit block
>> protection only (2) is used and this patch has been implemented based
>> on this fact.
>> 
>>> It is rather one formula (A) for flashes which don't
>>> exhaust
>>> the BP bits (eg. for 3 bits this would be flashes <= 16Mbit and for
>>> 4
>>> bits
>>> this would be for flashes <=8Gbit) and one (B) for the flashes where
>>> every
>>> BP bit combination is used. What is at the moment in the kernel is
>>> the
>>> second one, thus it will fail for flashes <= 16Mbit and 3 BP bits;
>>> and
>>> it
>>> also fails for all flashes with 4 bits. My patch does a fixup on (B)
>>> to
>>> match the results of (A), because doing this is less invasive; and as
>>> mentioned in the patch annex, might also be rewritten for a better
>>> understanding.
>> 
>> I've never seen spi flashes greater than 8Gbit (maybe you also), so I
>> am not sure whether the three rules are applicable to 4 bit block
>> protection. Even the three rules doesn't seem to be general enough for
>> 3bit or 2bit block protection.
>> 
>>> 
>>> 
>>> -michael
>>> 
>>>> 
>>>>>> 
>>>>>> We need new fomula based on n_sectors for BP3 at least.
>>>>> 
>>>>> No they are the same, but yes there is a bug in the current
>>>>> implementation.
>>>>> 
>>>>> -michael
>>>>> 
>>>>>> 
>>>>>>> So for the 3 bit case the following flashes are border cases:
>>>>>>>   - 16mbit (less settings than slots)
>>>>>>>   - 32mbit (number of settings and free slots match)
>>>>>>>   - 64mbit (more settings than slots, first setting is
>>>>>>> discarded)
>>>>>>> 
>>>>>>> That being said, I suspect all the 16mbit flashes (and below)
>>>>>>> which
>>>>>>> have
>>>>>>> the _LOCK bit set are broken, because the entries has to be
>>>>>>> shifted.
>>>>>>> I'll
>>>>>>> look into that later. This is the same "issue" you have with
>>>>>>> the
>>>>>>> 4
>>>>>>> bits.
>>>>>>> So if this is fixed, you should not need another formula for
>>>>>>> the
>>>>>>> 4
>>>>>>> bit
>>>>>>> case.
>>>>>>> 
>>>>>>>> We need new calculation method for 4bit block protection
>>>>>>>> and
>>>>>>>> for
>>>>>>>> making
>>>>>>>> it more generic, I choose n_sectors.
>>>>>>>> 
>>>>>>>> On all the flashes I checked, n_sectors is proper value for
>>>>>>>> getting
>>>>>>>> block protected portion.
>>>>>>>> 
>>>>>>>> 		density	portion	n_sectors
>>>>>>>> W25M512JV	64MB	1/512	512
>>>>>>>> N25Q128A	16MB	1/256	256
>>>>>>>> N25Q512A	64MB	1/1024	1024
>>>>>>>> MT25QL02GCBB	256MB	1/4096	4096
>>>>>>> 
>>>>>>> The rules above apply to these flashes, too. Could you double
>>>>>>> check
>>>>>>> that?
>>>>>>> 
>>>>>>> -michael
>>>>>>> 
>>>>>>>> 
>>>>>>>>>> +		val = val << SR_BP_SHIFT;
>>>>>>>>>> +
>>>>>>>>>> +		if (val & BIT(5) && mask & SR_BP3_BIT6)
>>>>>>>>>> +			val = (val & ~BIT(5)) | BIT(6);
>>>>>>>>>> +	} else {
>>>>>>>>>> +		val = mask - (pow << SR_BP_SHIFT);
>>>>>>>>>> +	}
>>>>>>>>>> +
>>>>>>>>>>  	if (val & ~mask)
>>>>>>>>>>  		return -EINVAL;
>>>>>>>>>>  	/* Don't "lock" with no region! */
>>>>>>>>>> @@ -1983,6 +2057,13 @@ static int stm_unlock(struct
>>>>>>>>>> spi_nor
>>>>>>>>>> *nor,
>>>>>>>>>> loff_t ofs, uint64_t len)
>>>>>>>>>> 
>>>>>>>>>>  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
>>>>>>>>>>  		tb_mask = SR_TB_BIT6;
>>>>>>>>>> +
>>>>>>>>>> +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
>>>>>>>>>> +		if (nor->flags &
>>>>>>>>>> SNOR_F_HAS_SR_BP3_BIT6)
>>>>>>>>>> +			mask = mask | SR_BP3_BIT6;
>>>>>>>>>> +		else
>>>>>>>>>> +			mask = mask | SR_BP3_BIT5;
>>>>>>>>>> +	}
>>>>>>>>>>  	/*
>>>>>>>>>>  	 * Need largest pow such that:
>>>>>>>>>>  	 *
>>>>>>>>>> @@ -1995,13 +2076,20 @@ static int stm_unlock(struct
>>>>>>>>>> spi_nor
>>>>>>>>>> *nor,
>>>>>>>>>> loff_t ofs, uint64_t len)
>>>>>>>>>>  	pow = ilog2(mtd->size) -
>>>>>>>>>> order_base_2(lock_len);
>>>>>>>>>>  	if (lock_len == 0) {
>>>>>>>>>>  		val = 0; /* fully unlocked */
>>>>>>>>>> +	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
>>>>>>>>>> +		val = ilog2(nor->n_sectors) + 1 - pow;
>>>>>>>>>> +		val = val << SR_BP_SHIFT;
>>>>>>>>>> +
>>>>>>>>>> +		if (val & BIT(5) && mask & SR_BP3_BIT6)
>>>>>>>>>> +			val = (val & ~BIT(5)) | BIT(6);
>>>>>>>>>>  	} else {
>>>>>>>>>>  		val = mask - (pow << SR_BP_SHIFT);
>>>>>>>>>> -		/* Some power-of-two sizes are not
>>>>>>>>>> supported */
>>>>>>>>>> -		if (val & ~mask)
>>>>>>>>>> -			return -EINVAL;
>>>>>>>>>>  	}
>>>>>>>>>> 
>>>>>>>>>> +	/* Some power-of-two sizes are not supported */
>>>>>>>>>> +	if (val & ~mask)
>>>>>>>>>> +		return -EINVAL;
>>>>>>>>>> +
>>>>>>>>>>  	status_new = (status_old & ~mask & ~tb_mask) |
>>>>>>>>>> val;
>>>>>>>>>> 
>>>>>>>>>>  	/* Don't protect status register if we're fully
>>>>>>>>>> unlocked */
>>>>>>>>>> @@ -4736,6 +4824,7 @@ static void
>>>>>>>>>> spi_nor_info_init_params(struct
>>>>>>>>>> spi_nor *nor)
>>>>>>>>>>  	/* Set SPI NOR sizes. */
>>>>>>>>>>  	params->size = (u64)info->sector_size * info-
>>>>>>>>>>> n_sectors;
>>>>>>>>>> 
>>>>>>>>>>  	params->page_size = info->page_size;
>>>>>>>>>> +	params->n_sectors = info->n_sectors;
>>>>>>>>>> 
>>>>>>>>>>  	if (!(info->flags & SPI_NOR_NO_FR)) {
>>>>>>>>>>  		/* Default to Fast Read for DT and non-
>>>>>>>>>> DT
>>>>>>>>>> platform
>>>>>>>>>> devices. */
>>>>>>>>>> @@ -5192,6 +5281,11 @@ int spi_nor_scan(struct spi_nor
>>>>>>>>>> *nor,
>>>>>>>>>> const
>>>>>>>>>> char *name,
>>>>>>>>>>  		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
>>>>>>>>>>  	if (info->flags & USE_CLSR)
>>>>>>>>>>  		nor->flags |= SNOR_F_USE_CLSR;
>>>>>>>>>> +	if (info->flags & SPI_NOR_HAS_BP3) {
>>>>>>>>>> +		nor->flags |= SNOR_F_HAS_SR_BP3;
>>>>>>>>>> +		if (info->flags & SPI_NOR_BP3_SR_BIT6)
>>>>>>>>>> +			nor->flags |=
>>>>>>>>>> SNOR_F_HAS_SR_BP3_BIT6;
>>>>>>>>>> +	}
>>>>>>>>>> 
>>>>>>>>>>  	if (info->flags & SPI_NOR_NO_ERASE)
>>>>>>>>>>  		mtd->flags |= MTD_NO_ERASE;
>>>>>>>>>> @@ -5199,6 +5293,7 @@ int spi_nor_scan(struct spi_nor
>>>>>>>>>> *nor,
>>>>>>>>>> const
>>>>>>>>>> char *name,
>>>>>>>>>>  	mtd->dev.parent = dev;
>>>>>>>>>>  	nor->page_size = params->page_size;
>>>>>>>>>>  	mtd->writebufsize = nor->page_size;
>>>>>>>>>> +	nor->n_sectors = params->n_sectors;
>>>>>>>>>> 
>>>>>>>>>>  	if (of_property_read_bool(np, "broken-flash-
>>>>>>>>>> reset"))
>>>>>>>>>>  		nor->flags |= SNOR_F_BROKEN_RESET;
>>>>>>>>>> diff --git a/include/linux/mtd/spi-nor.h
>>>>>>>>>> b/include/linux/mtd/spi-
>>>>>>>>>> nor.h
>>>>>>>>>> index 541c06d042e8..92d550501daf 100644
>>>>>>>>>> --- a/include/linux/mtd/spi-nor.h
>>>>>>>>>> +++ b/include/linux/mtd/spi-nor.h
>>>>>>>>>> @@ -129,7 +129,9 @@
>>>>>>>>>>  #define SR_BP1			BIT(3)	/* Block
>>>>>>>>>> protect 1
>>>>>>>>>> */
>>>>>>>>>>  #define SR_BP2			BIT(4)	/* Block
>>>>>>>>>> protect 2
>>>>>>>>>> */
>>>>>>>>>>  #define SR_TB_BIT5		BIT(5)	/* Top/Bottom
>>>>>>>>>> protect
>>>>>>>>>> */
>>>>>>>>>> +#define SR_BP3_BIT5		BIT(5)	/* Block
>>>>>>>>>> protect 3
>>>>>>>>>> */
>>>>>>>>> 
>>>>>>>>> maybe just name it SR_BP3? would also be more consistent
>>>>>>>>> with
>>>>>>>>> the
>>>>>>>>> proposal
>>>>>>>>> above.
>>>>>>>>> 
>>>>>>>>>>  #define SR_TB_BIT6		BIT(6)	/* Top/Bottom
>>>>>>>>>> protect
>>>>>>>>>> */
>>>>>>>>>> +#define SR_BP3_BIT6		BIT(6)	/* Block
>>>>>>>>>> protect 3
>>>>>>>>>> */
>>>>>>>>>>  #define SR_SRWD			BIT(7)	/* SR
>>>>>>>>>> write
>>>>>>>>>> protect
>>>>>>>>>> */
>>>>>>>>>>  /* Spansion/Cypress specific status bits */
>>>>>>>>>>  #define SR_E_ERR		BIT(5)
>>>>>>>>>> @@ -248,6 +250,8 @@ enum spi_nor_option_flags {
>>>>>>>>>>  	SNOR_F_HAS_16BIT_SR	= BIT(9),
>>>>>>>>>>  	SNOR_F_NO_READ_CR	= BIT(10),
>>>>>>>>>>  	SNOR_F_HAS_SR_TB_BIT6	= BIT(11),
>>>>>>>>>> +	SNOR_F_HAS_SR_BP3	= BIT(12),
>>>>>>>>>> +	SNOR_F_HAS_SR_BP3_BIT6	= BIT(13),
>>>>>>>>>> 
>>>>>>>>>>  };
>>>>>>>>>> 
>>>>>>>>>> @@ -519,6 +523,7 @@ struct spi_nor_locking_ops {
>>>>>>>>>>   *
>>>>>>>>>>   * @size:		the flash memory density in
>>>>>>>>>> bytes.
>>>>>>>>>>   * @page_size:		the page size of the SPI NOR
>>>>>>>>>> flash
>>>>>>>>>> memory.
>>>>>>>>>> + * @n_sectors:		number of sectors
>>>>>>>>>>   * @hwcaps:		describes the read and page
>>>>>>>>>> program
>>>>>>>>>> hardware
>>>>>>>>>>   *			capabilities.
>>>>>>>>>>   * @reads:		read capabilities ordered by
>>>>>>>>>> priority:
>>>>>>>>>> the
>>>>>>>>>> higher index
>>>>>>>>>> @@ -541,6 +546,7 @@ struct spi_nor_locking_ops {
>>>>>>>>>>  struct spi_nor_flash_parameter {
>>>>>>>>>>  	u64				size;
>>>>>>>>>>  	u32				page_size;
>>>>>>>>>> +	u16				n_sectors;
>>>>>>>>>> 
>>>>>>>>>>  	struct spi_nor_hwcaps		hwcaps;
>>>>>>>>>>  	struct spi_nor_read_command	reads[SNOR_CMD_
>>>>>>>>>> READ_MAX
>>>>>>>>>> ];
>>>>>>>>>> @@ -573,6 +579,7 @@ struct flash_info;
>>>>>>>>>>   * @bouncebuf_size:	size of the bounce buffer
>>>>>>>>>>   * @info:		spi-nor part JDEC MFR id and
>>>>>>>>>> other info
>>>>>>>>>>   * @page_size:		the page size of the SPI NOR
>>>>>>>>>> + * @n_sector:		number of sectors
>>>>>>>>>>   * @addr_width:		number of address bytes
>>>>>>>>>>   * @erase_opcode:	the opcode for erasing a sector
>>>>>>>>>>   * @read_opcode:	the read opcode
>>>>>>>>>> @@ -599,6 +606,7 @@ struct spi_nor {
>>>>>>>>>>  	size_t			bouncebuf_size;
>>>>>>>>>>  	const struct flash_info	*info;
>>>>>>>>>>  	u32			page_size;
>>>>>>>>>> +	u16			n_sectors;
>>>>>>>>>>  	u8			addr_width;
>>>>>>>>>>  	u8			erase_opcode;
>>>>>>>>>>  	u8			read_opcode;
>>>>>>>>>> --
>>>>>>>>>> 2.17.1
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>> ______________________________________________________
>>>>>>>>>> Linux MTD discussion mailing list
>>>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>> 
>>>>>> 
>>>> 
>>>> 
>> https://protect2.fireeye.com/url?k=06b6dd5d-5b7d5a63-06b75612-0cc47a31309a-83164929001f7741&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
>>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>> 
>>>>> 
>>> 
>>> 
>> 
>> Thanks,
>> Jungseung Lee
>> 

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [SPAM] Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Hi, 

2020-02-03 (Mon), 15:38 +0100, Michael Walle:
> Am 2020-02-03 14:56, schrieb Vignesh Raghavendra:
> > Hi Michael,
> > 
> > On 30/01/20 1:47 pm, Jungseung Lee wrote:
> > [...]
> > 
> > > > > > > > > > >  	/*
> > > > > > > > > > >  	 * Need smallest pow such that:
> > > > > > > > > > >  	 *
> > > > > > > > > > > @@ -1908,7 +1972,17 @@ static int stm_lock(struct
> > > > > > > > > > > spi_nor
> > > > > > > > > > > *nor,
> > > > > > > > > > > loff_t ofs, uint64_t len)
> > > > > > > > > > >  	 *   pow = ceil(log2(size / len)) = log2(size)
> > > > > > > > > > > -
> > > > > > > > > > > floor(log2(len))
> > > > > > > > > > >  	 */
> > > > > > > > > > >  	pow = ilog2(mtd->size) - ilog2(lock_len);
> > > > > > > > > > > -	val = mask - (pow << SR_BP_SHIFT);
> > > > > > > > > > > +
> > > > > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > > > > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
> > > > > > > > > > 
> > > > > > > > > > Why do you use a new calculation here? As far as I
> > > > > > > > > > can
> > > > > > > > > > see,
> > > > > > > > > > the
> > > > > > > > > > method is
> > > > > > > > > > the same except that is has one bit more. That also
> > > > > > > > > > raises
> > > > > > > > > > the
> > > > > > > > > > question why
> > > > > > > > > > n_sectors is now needed?
> > > > > > > > > > 
> > 
> > Flash devices have variable sector size, 64KB, 128KB or 256KB...
> > While
> > mapping of number of sectors locked to BP bits is dependent on
> > rules 1
> > to 3 you mentioned below, the size or area of flash protected
> > depends 
> > on
> > sector size.
> 
> Is there any flash device which has another sector size != 64KiB for
> the 
> BP bits?
> 

Please see my previous answer.

>>>> No, it must be based on n_sectors. To make 4bit block protection
>>>> more
>>>> generic, the lock sector size must NOT fixed as 64KB (as can be
>>>> checked
>>>> from your patch). See "mt35xu02g" and check the protected area and
>>>> number of sectors from it's datasheet.

Thanks,

> > So, the current formula in spi-nor.c (ignoring TB and other 
> > boilerplate):
> > 
> > pow = ilog2(mtd->size) - ilog2(lock_len);
> > val = mask - (pow << shift);
> > 
> > This works only for devices with 64KB sector size as 8MB flash
> > with 
> > 64KB
> > sector size would have 128 sectors (BP0-2 => 0b111 => 2^7).
> 
> It also only works with flashes >= 4MiB. See fix below. And IMHO this
> is 
> exactly
> the same "problem" the flashes with 4 BP bits have.
> 
> > A more generic formula would be:
> > 
> > Find n where 2^(n - 1) = len/sector-size
> > OR 2^ (n - 1) = len * n_sectors / mtd->size
> > 
> > Which solves to:
> > 
> > pow = ilog2(mtd->size) - ilog2(lock_len);
> > val = ilog2(nor->n_sectors) + 1 - pow;
> > 
> > I see this is what Jungseung has tried to implement here.  Please
> > correct me if I got this wrong.
> > 
> > This, combined with point (3) below should provide a generic
> > implementation that should support a wide variety of flashes.
> > 
> > Of course, there are always exceptions and they need to be handled 
> > using
> > custom hooks.
> > 
> > I don't have the patch that you shared with Jungseung. I would
> > greatly
> > appreciate, if you and Jungseung could work on patch with above
> > logic 
> > as
> > well as fixes to handle overflow case?
> 
> 
https://lore.kernel.org/linux-mtd/20200123170130.8289-1-michael@walle.cc/
> 
> As I said, that should work for both 3 and 4 bits. But be aware that 
> this
> is an RFC and I've just tested it in in userspace, like the
> calculation
> of the bits and transferred that into the driver. So one would
> actually
> have to test that. But apparently no one had a even applied it.
> 
> -michael
> 
> > 
> > Thanks a lot Jungseung and Michael for your efforts!
> > 
> > Regards
> > Vignesh
> > 
> > > > > > > > > > Can't we just initialize the mask with
> > > > > > > > > > 
> > > > > > > > > > mask = SR_BP2 | SR_BP1 | SR_BP0;
> > > > > > > > > > if (nor->flags & SNOR_F_HAS_SR_BP3)
> > > > > > > > > >     mask |= SR_BP3_BIT5;
> > > > > > > > > > 
> > > > > > > > > > do the calculation and checks and then move the
> > > > > > > > > > SR_BP3_BIT5
> > > > > > > > > > to
> > > > > > > > > > SR_BP3_BIT6
> > > > > > > > > > if SNOR_F_HAS_SR_BP3_BIT6 is set.
> > > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > For most of flashes that supporting BP0-2, the
> > > > > > > > > smallest
> > > > > > > > > protected
> > > > > > > > > portion is fixed as 1/64
> > > > > > > > > and it can be properly handled by existing
> > > > > > > > > calculation. (Actually it's not fully generic, see
> > > > > > > > > flashes
> > > > > > > > > like
> > > > > > > > > w25q40bw or m25p80. Of course, it doesn't have
> > > > > > > > > SPI_NOR_HAS_LOCK
> > > > > > > > > flag
> > > > > > > > > even though it has BP0-2 bit in SR)
> > > > > > > > 
> > > > > > > > No. The rules are always the same wether there are
> > > > > > > > three or
> > > > > > > > four
> > > > > > > > BP
> > > > > > > > bits (the example in stm_lock() has not enough
> > > > > > > > information on
> > > > > > > > this):
> > > > > > > > 
> > > > > > > > (1) the first setting (besides 0) protects one sector.
> > > > > > > > The
> > > > > > > > second
> > > > > > > >      protects 2, the third 4 and so on. eg 2^N
> > > > > > > > (2) the last setting is _always_ protect all, just like
> > > > > > > > the
> > > > > > > > '0'
> > > > > > > > setting
> > > > > > > >      is always protect none.
> > > > > > > > (3) if there is an overflow because there are no more
> > > > > > > > free
> > > > > > > > slots
> > > > > > > > for
> > > > > > > >      further settings (for 3 bits with flashes >
> > > > > > > > 32MBit, for
> > > > > > > > 4
> > > > > > > >      bits if should be flashes > 16GBit), the first
> > > > > > > > entry
> > > > > > > > will be
> > > > > > > >      discarded (eg the very first is the "just one
> > > > > > > > sector"
> > > > > > > > entry).
> > > > > > > > 
> > > > > > > > This is true for all flashes which uses this kind of
> > > > > > > > setting,
> > > > > > > > have a
> > > > > > > > look at the m25p80 or w25q40bw, these are no exception.
> > > > > > > > It is
> > > > > > > > just
> > > > > > > > the
> > > > > > > > notation "lower 1/64" which is only true for flashes
> > > > > > > > which
> > > > > > > > either
> > > > > > > > overflows in (3) or fill all entries (eg. with 3bits
> > > > > > > > that
> > > > > > > > would
> > > > > > > > be
> > > > > > > > the
> > > > > > > > 32Mbit version).
> > > > > > > > 
> > > > > > > 
> > > > > > > Looks like you noticed that we need new calculation
> > > > > > > method that
> > > > > > > would
> > > > > > > be based on n_sectors :).
> > > > > > 
> > > > > > No it will work without that (if I'm not mistaken). Give me
> > > > > > some
> > > > > > time
> > > > > > and I'll post a patch.
> > > > > 
> > > > > No, it must be based on n_sectors. To make 4bit block
> > > > > protection
> > > > > more
> > > > > generic, the lock sector size must NOT fixed as 64KB (as can
> > > > > be
> > > > > checked
> > > > > from your patch). See "mt35xu02g" and check the protected
> > > > > area and
> > > > > number of sectors from it's datasheet.
> > > > 
> > > > There is no public datasheet as far as I can see. And yes,
> > > > actually
> > > > n_sectors is my "mtd-size / sector_size". But I don't see how
> > > > n_sectors
> > > > would help if the sector size changes.
> > > > 
> > > > > The rule you mentioned "the first setting (besides 0)
> > > > > protects one
> > > > > sector" is alawys true for *4bit* block protection. That's
> > > > > why I
> > > > > choose
> > > > > n_sectors for new calculation.
> > > > 
> > > > And how does flashes behave once all the free slots are full?
> > > > It was
> > > > the
> > > > same with the 3bit flashes, they only overflowed with
> > > > "newer"/bigger
> > > > flashes.
> > > > 
> > > > 
> > > > > > 
> > > > > > > Rule (1) is NOT true for some flashes
> > > > > > > supporting BP0-2 and that's why I said that smallest
> > > > > > > protected
> > > > > > > portion
> > > > > > > is fixed as '1/64' for these flashes.
> > > > > > 
> > > > > > No, you have to apply rule (3). (1) is only the starting
> > > > > > point.
> > > > > > It
> > > > > > is
> > > > > > kind
> > > > > > of a sliding window.
> > > > > > 
> > > > > > > See this one.
> > > > > > > 
> > > > > > > W25Q20EW	256KB	1/4 ... = 64KB		BP2
> > > > > > > W25Q128JV	16MB	1/64 ... = 256KB	BP2 <--
> > > > > > > S25FL132K	4MB	1/64 ... = 64KB		BP2 <--
> > > > > > > S25FL164K	8MB
> > > > > > > 1/64 ... = 128KB	BP2 <--
> > > > > > 
> > > > > > All these flashes need (3) to be applied, thus (1) doesn't
> > > > > > apply
> > > > > > anymore.
> > > > > > 
> > > > > > Let me give you an example for the 64MBit case, the
> > > > > > settings
> > > > > > would
> > > > > > be:
> > > > > > 
> > > > > > 0 sectors (corresponds to protect none)
> > > > > > 1 sector
> > > > > > 2 sectors
> > > > > > 4 sectors
> > > > > > 8 sectors
> > > > > > 16 sectors
> > > > > > 32 sectors
> > > > > > 64 sectors
> > > > > > 128 sectors (corresponds to protect all)
> > > > > > 
> > > > > > Unfortunately, we have only 8 slots (because 3 BP bits),
> > > > > > therefore
> > > > > > we
> > > > > > have
> > > > > > to discard some setting. According to rule (2) 0 is always
> > > > > > "protect
> > > > > > none"
> > > > > > and 7 is always "protect all". Thus we have 6 settings
> > > > > > left.
> > > > > > According
> > > > > > to
> > > > > > rule (3) we discard the first ones. In this case, this is
> > > > > > the "1
> > > > > > sector"
> > > > > > setting. Thus we end up with the following possible
> > > > > > settings:
> > > > > > 
> > > > > > 0 sectors (corresponds to protect none)
> > > > > > 2 sectors
> > > > > > 4 sectors
> > > > > > 8 sectors
> > > > > > 16 sectors
> > > > > > 32 sectors
> > > > > > 64 sectors
> > > > > > 128 sectors (corresponds to protect all)
> > > > > > 
> > > > > > If you have a 128Mbit flash, the next setting that would be
> > > > > > discarded
> > > > > > is
> > > > > > "2 sectors". Thus it would start with:
> > > > > > 
> > > > > > 0 sectors (corresponds to protect none)
> > > > > > 4 sectors
> > > > > > [..]
> > > > > > 256 sectors (corresponds to protect all)
> > > > > > 
> > > > > > 
> > > > > > Another example W25Q20EW, following possible settings:
> > > > > > 
> > > > > > 0 sectors (corresponds to protect none)
> > > > > > 1 sector
> > > > > > 2 sectors
> > > > > > 4 sectors (corresponds to protect all)
> > > > > > 
> > > > > > We now have less settings then our 8 possible slots. So
> > > > > > this is
> > > > > > where
> > > > > > rule (1) applies, because according to that the "1 sector"
> > > > > > setting is
> > > > > > the first possible setting besides 0.
> > > > > > 
> > > > > > And this also applies to the 4 bit protection bits.
> > > > > > 
> > > > > > 
> > > > > > 
> > > > > > > W25Q256JV	32MB	1/512 ... =
> > > > > > > 64KB	BP3
> > > > > > > S25FL128L	16MB	1/256 ... = 64KB	BP3
> > > > > > > S25FL256L	32MB	1/512 ... = 64KB	BP3
> > > > > > > 
> > > > > > > In current BP implementation, block protection is just
> > > > > > > working
> > > > > > > for
> > > > > > > some
> > > > > > > flashes that has smallest protected portion as '1/64'.
> > > > > > 
> > > > > > No its currently working for all except flashes smaller
> > > > > > than
> > > > > > 32Mbit.
> > > > > 
> > > > > No. Not working for flashes supporting 4bit block protection.
> > > > > 
> > > > > > Applied to the 4 bits, this would mean "it works for all
> > > > > > except
> > > > > > flashes
> > > > > > smaller than 8Gbit" which are practially all. As I said,
> > > > > > this is
> > > > > > a
> > > > > > bug
> > > > > > and once this bug is fixed, there should be no difference
> > > > > > between
> > > > > > 3
> > > > > > and 4 bits.
> > > > > > 
> > > > > > -michael
> > > > > > 
> > > > > 
> > > > > The exact fact is that locks operate in two different ways
> > > > > according to
> > > > > flash model.
> > > > > 
> > > > > (1) the smallest protected portion is fixed.
> > > > > 	for BP0-2 : 1/64
> > > > > 	for BP0-1 : 1/4
> > > > 
> > > > As mentioned earlier, the ratio nomenclature is missleading and
> > > > only
> > > > valid if the table is completely filled up.
> > > > 
> > > > Take a flash with 128kB and three BP bits (or even only two BP
> > > > bits).
> > > > The
> > > > smallest portion will be 64kB (which is one sector and not
> > > > 1/64).
> > > > 
> > > > Thus the smallest portion is always one sector, unless the
> > > > table is
> > > > overflowing, then the smallest will settle to 1/4 (for two),
> > > > 1/64
> > > > (for
> > > > three)
> > > > and 1/16384 (for four bits).
> > > > 
> > > > > (2) the smallest protected portion is inversely propotional
> > > > > with
> > > > > number
> > > > > of sectors.
> > > > > 
> > > > > For the flashes supporting 3bit block protection, (1) and (2)
> > > > > are
> > > > > mixed
> > > > > and used. But all the flashes supporting 4bit block
> > > > > protection
> > > > > listed
> > > > > on spi-nor.c, only (2) is used.
> > > > 
> > > > It is not mixed it just depends on the flash size (and the
> > > > number of
> > > > protection bits).
> > > > 
> > > 
> > > It is mixed. Let's compare "en25qh128" from EON with "w25q128jv"
> > > from
> > > Winbond. They have the same capacity(128MBit) and also supporting
> > > 3bit
> > > block protection. (Note that the named BP3 bit of "en25qh128" is
> > > working exactly same with T/B bit.)
> > > 
> > > "en25qh128" is following (2) and "w25q128jv" is following (1).
> > > It 
> > > seems
> > > impossible to distinguish them by the flash size or the number of
> > > protection bits.
> > > 
> > > I also still have no idea how your three rules are applicable for
> > > 2bit
> > > block protection (bp0-1).
> > > 
> > > > > Each method requires each formula. I have no idea how to
> > > > > handle it
> > > > > with
> > > > > one formula (probably adding number of exceptional handling?)
> > > > > without
> > > > > any sectional flag. "w25q128jv(bp0-2)" is following (1) and
> > > > > "n25q128a(bp0-3)" is following (2).
> > > > 
> > > > Well one uses three BPs the other four, and they all follow the
> > > > three
> > > > rules
> > > > above. Did you try my patch? Because I've (at least in
> > > > userspace)
> > > > tested
> > > > it with 4 bits and got the correct results.
> > > > 
> > > > And yes, its actually two different formulas, but not for 3 and
> > > > 4
> > > > bits like in your patch.
> > > 
> > > The title of my patch is "add 4bit block protection support". I
> > > just
> > > let 3bit block protection as it is, I've implemented something
> > > what I
> > > could check. As I mentioned, for all the flashes supporting 4bit
> > > block
> > > protection only (2) is used and this patch has been implemented
> > > based
> > > on this fact.
> > > 
> > > > It is rather one formula (A) for flashes which don't
> > > > exhaust
> > > > the BP bits (eg. for 3 bits this would be flashes <= 16Mbit and
> > > > for
> > > > 4
> > > > bits
> > > > this would be for flashes <=8Gbit) and one (B) for the flashes
> > > > where
> > > > every
> > > > BP bit combination is used. What is at the moment in the kernel
> > > > is
> > > > the
> > > > second one, thus it will fail for flashes <= 16Mbit and 3 BP
> > > > bits;
> > > > and
> > > > it
> > > > also fails for all flashes with 4 bits. My patch does a fixup
> > > > on (B)
> > > > to
> > > > match the results of (A), because doing this is less invasive;
> > > > and as
> > > > mentioned in the patch annex, might also be rewritten for a
> > > > better
> > > > understanding.
> > > 
> > > I've never seen spi flashes greater than 8Gbit (maybe you also),
> > > so I
> > > am not sure whether the three rules are applicable to 4 bit block
> > > protection. Even the three rules doesn't seem to be general
> > > enough for
> > > 3bit or 2bit block protection.
> > > 
> > > > 
> > > > 
> > > > -michael
> > > > 
> > > > > 
> > > > > > > 
> > > > > > > We need new fomula based on n_sectors for BP3 at least.
> > > > > > 
> > > > > > No they are the same, but yes there is a bug in the current
> > > > > > implementation.
> > > > > > 
> > > > > > -michael
> > > > > > 
> > > > > > > 
> > > > > > > > So for the 3 bit case the following flashes are border
> > > > > > > > cases:
> > > > > > > >   - 16mbit (less settings than slots)
> > > > > > > >   - 32mbit (number of settings and free slots match)
> > > > > > > >   - 64mbit (more settings than slots, first setting is
> > > > > > > > discarded)
> > > > > > > > 
> > > > > > > > That being said, I suspect all the 16mbit flashes (and
> > > > > > > > below)
> > > > > > > > which
> > > > > > > > have
> > > > > > > > the _LOCK bit set are broken, because the entries has
> > > > > > > > to be
> > > > > > > > shifted.
> > > > > > > > I'll
> > > > > > > > look into that later. This is the same "issue" you have
> > > > > > > > with
> > > > > > > > the
> > > > > > > > 4
> > > > > > > > bits.
> > > > > > > > So if this is fixed, you should not need another
> > > > > > > > formula for
> > > > > > > > the
> > > > > > > > 4
> > > > > > > > bit
> > > > > > > > case.
> > > > > > > > 
> > > > > > > > > We need new calculation method for 4bit block
> > > > > > > > > protection
> > > > > > > > > and
> > > > > > > > > for
> > > > > > > > > making
> > > > > > > > > it more generic, I choose n_sectors.
> > > > > > > > > 
> > > > > > > > > On all the flashes I checked, n_sectors is proper
> > > > > > > > > value for
> > > > > > > > > getting
> > > > > > > > > block protected portion.
> > > > > > > > > 
> > > > > > > > > 		density	portion	n_sectors
> > > > > > > > > W25M512JV	64MB	1/512	512
> > > > > > > > > N25Q128A	16MB	1/256	256
> > > > > > > > > N25Q512A	64MB	1/1024	1024
> > > > > > > > > MT25QL02GCBB	256MB	1/4096	4096
> > > > > > > > 
> > > > > > > > The rules above apply to these flashes, too. Could you
> > > > > > > > double
> > > > > > > > check
> > > > > > > > that?
> > > > > > > > 
> > > > > > > > -michael
> > > > > > > > 
> > > > > > > > > 
> > > > > > > > > > > +		val = val << SR_BP_SHIFT;
> > > > > > > > > > > +
> > > > > > > > > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
> > > > > > > > > > > +			val = (val & ~BIT(5)) | BIT(6);
> > > > > > > > > > > +	} else {
> > > > > > > > > > > +		val = mask - (pow << SR_BP_SHIFT);
> > > > > > > > > > > +	}
> > > > > > > > > > > +
> > > > > > > > > > >  	if (val & ~mask)
> > > > > > > > > > >  		return -EINVAL;
> > > > > > > > > > >  	/* Don't "lock" with no region! */
> > > > > > > > > > > @@ -1983,6 +2057,13 @@ static int
> > > > > > > > > > > stm_unlock(struct
> > > > > > > > > > > spi_nor
> > > > > > > > > > > *nor,
> > > > > > > > > > > loff_t ofs, uint64_t len)
> > > > > > > > > > > 
> > > > > > > > > > >  	if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
> > > > > > > > > > >  		tb_mask = SR_TB_BIT6;
> > > > > > > > > > > +
> > > > > > > > > > > +	if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > > > > > > +		if (nor->flags &
> > > > > > > > > > > SNOR_F_HAS_SR_BP3_BIT6)
> > > > > > > > > > > +			mask = mask | SR_BP3_BIT6;
> > > > > > > > > > > +		else
> > > > > > > > > > > +			mask = mask | SR_BP3_BIT5;
> > > > > > > > > > > +	}
> > > > > > > > > > >  	/*
> > > > > > > > > > >  	 * Need largest pow such that:
> > > > > > > > > > >  	 *
> > > > > > > > > > > @@ -1995,13 +2076,20 @@ static int
> > > > > > > > > > > stm_unlock(struct
> > > > > > > > > > > spi_nor
> > > > > > > > > > > *nor,
> > > > > > > > > > > loff_t ofs, uint64_t len)
> > > > > > > > > > >  	pow = ilog2(mtd->size) -
> > > > > > > > > > > order_base_2(lock_len);
> > > > > > > > > > >  	if (lock_len == 0) {
> > > > > > > > > > >  		val = 0; /* fully unlocked */
> > > > > > > > > > > +	} else if (nor->flags & SNOR_F_HAS_SR_BP3) {
> > > > > > > > > > > +		val = ilog2(nor->n_sectors) + 1 - pow;
> > > > > > > > > > > +		val = val << SR_BP_SHIFT;
> > > > > > > > > > > +
> > > > > > > > > > > +		if (val & BIT(5) && mask & SR_BP3_BIT6)
> > > > > > > > > > > +			val = (val & ~BIT(5)) | BIT(6);
> > > > > > > > > > >  	} else {
> > > > > > > > > > >  		val = mask - (pow << SR_BP_SHIFT);
> > > > > > > > > > > -		/* Some power-of-two sizes are not
> > > > > > > > > > > supported */
> > > > > > > > > > > -		if (val & ~mask)
> > > > > > > > > > > -			return -EINVAL;
> > > > > > > > > > >  	}
> > > > > > > > > > > 
> > > > > > > > > > > +	/* Some power-of-two sizes are not supported */
> > > > > > > > > > > +	if (val & ~mask)
> > > > > > > > > > > +		return -EINVAL;
> > > > > > > > > > > +
> > > > > > > > > > >  	status_new = (status_old & ~mask & ~tb_mask) |
> > > > > > > > > > > val;
> > > > > > > > > > > 
> > > > > > > > > > >  	/* Don't protect status register if we're fully
> > > > > > > > > > > unlocked */
> > > > > > > > > > > @@ -4736,6 +4824,7 @@ static void
> > > > > > > > > > > spi_nor_info_init_params(struct
> > > > > > > > > > > spi_nor *nor)
> > > > > > > > > > >  	/* Set SPI NOR sizes. */
> > > > > > > > > > >  	params->size = (u64)info->sector_size * info-
> > > > > > > > > > > > n_sectors;
> > > > > > > > > > > 
> > > > > > > > > > >  	params->page_size = info->page_size;
> > > > > > > > > > > +	params->n_sectors = info->n_sectors;
> > > > > > > > > > > 
> > > > > > > > > > >  	if (!(info->flags & SPI_NOR_NO_FR)) {
> > > > > > > > > > >  		/* Default to Fast Read for DT and non-
> > > > > > > > > > > DT
> > > > > > > > > > > platform
> > > > > > > > > > > devices. */
> > > > > > > > > > > @@ -5192,6 +5281,11 @@ int spi_nor_scan(struct
> > > > > > > > > > > spi_nor
> > > > > > > > > > > *nor,
> > > > > > > > > > > const
> > > > > > > > > > > char *name,
> > > > > > > > > > >  		nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;
> > > > > > > > > > >  	if (info->flags & USE_CLSR)
> > > > > > > > > > >  		nor->flags |= SNOR_F_USE_CLSR;
> > > > > > > > > > > +	if (info->flags & SPI_NOR_HAS_BP3) {
> > > > > > > > > > > +		nor->flags |= SNOR_F_HAS_SR_BP3;
> > > > > > > > > > > +		if (info->flags & SPI_NOR_BP3_SR_BIT6)
> > > > > > > > > > > +			nor->flags |=
> > > > > > > > > > > SNOR_F_HAS_SR_BP3_BIT6;
> > > > > > > > > > > +	}
> > > > > > > > > > > 
> > > > > > > > > > >  	if (info->flags & SPI_NOR_NO_ERASE)
> > > > > > > > > > >  		mtd->flags |= MTD_NO_ERASE;
> > > > > > > > > > > @@ -5199,6 +5293,7 @@ int spi_nor_scan(struct
> > > > > > > > > > > spi_nor
> > > > > > > > > > > *nor,
> > > > > > > > > > > const
> > > > > > > > > > > char *name,
> > > > > > > > > > >  	mtd->dev.parent = dev;
> > > > > > > > > > >  	nor->page_size = params->page_size;
> > > > > > > > > > >  	mtd->writebufsize = nor->page_size;
> > > > > > > > > > > +	nor->n_sectors = params->n_sectors;
> > > > > > > > > > > 
> > > > > > > > > > >  	if (of_property_read_bool(np, "broken-flash-
> > > > > > > > > > > reset"))
> > > > > > > > > > >  		nor->flags |= SNOR_F_BROKEN_RESET;
> > > > > > > > > > > diff --git a/include/linux/mtd/spi-nor.h
> > > > > > > > > > > b/include/linux/mtd/spi-
> > > > > > > > > > > nor.h
> > > > > > > > > > > index 541c06d042e8..92d550501daf 100644
> > > > > > > > > > > --- a/include/linux/mtd/spi-nor.h
> > > > > > > > > > > +++ b/include/linux/mtd/spi-nor.h
> > > > > > > > > > > @@ -129,7 +129,9 @@
> > > > > > > > > > >  #define SR_BP1			BIT(3)	/
> > > > > > > > > > > * Block
> > > > > > > > > > > protect 1
> > > > > > > > > > > */
> > > > > > > > > > >  #define SR_BP2			BIT(4)	/
> > > > > > > > > > > * Block
> > > > > > > > > > > protect 2
> > > > > > > > > > > */
> > > > > > > > > > >  #define SR_TB_BIT5		BIT(5)	/
> > > > > > > > > > > * Top/Bottom
> > > > > > > > > > > protect
> > > > > > > > > > > */
> > > > > > > > > > > +#define SR_BP3_BIT5		BIT(5)	/
> > > > > > > > > > > * Block
> > > > > > > > > > > protect 3
> > > > > > > > > > > */
> > > > > > > > > > 
> > > > > > > > > > maybe just name it SR_BP3? would also be more
> > > > > > > > > > consistent
> > > > > > > > > > with
> > > > > > > > > > the
> > > > > > > > > > proposal
> > > > > > > > > > above.
> > > > > > > > > > 
> > > > > > > > > > >  #define SR_TB_BIT6		BIT(6)	/
> > > > > > > > > > > * Top/Bottom
> > > > > > > > > > > protect
> > > > > > > > > > > */
> > > > > > > > > > > +#define SR_BP3_BIT6		BIT(6)	/
> > > > > > > > > > > * Block
> > > > > > > > > > > protect 3
> > > > > > > > > > > */
> > > > > > > > > > >  #define SR_SRWD			BIT(7)	/
> > > > > > > > > > > * SR
> > > > > > > > > > > write
> > > > > > > > > > > protect
> > > > > > > > > > > */
> > > > > > > > > > >  /* Spansion/Cypress specific status bits */
> > > > > > > > > > >  #define SR_E_ERR		BIT(5)
> > > > > > > > > > > @@ -248,6 +250,8 @@ enum spi_nor_option_flags {
> > > > > > > > > > >  	SNOR_F_HAS_16BIT_SR	= BIT(9),
> > > > > > > > > > >  	SNOR_F_NO_READ_CR	= BIT(10),
> > > > > > > > > > >  	SNOR_F_HAS_SR_TB_BIT6	= BIT(11),
> > > > > > > > > > > +	SNOR_F_HAS_SR_BP3	= BIT(12),
> > > > > > > > > > > +	SNOR_F_HAS_SR_BP3_BIT6	= BIT(13),
> > > > > > > > > > > 
> > > > > > > > > > >  };
> > > > > > > > > > > 
> > > > > > > > > > > @@ -519,6 +523,7 @@ struct spi_nor_locking_ops {
> > > > > > > > > > >   *
> > > > > > > > > > >   * @size:		the flash memory
> > > > > > > > > > > density in
> > > > > > > > > > > bytes.
> > > > > > > > > > >   * @page_size:		the page size of the
> > > > > > > > > > > SPI NOR
> > > > > > > > > > > flash
> > > > > > > > > > > memory.
> > > > > > > > > > > + * @n_sectors:		number of sectors
> > > > > > > > > > >   * @hwcaps:		describes the read and
> > > > > > > > > > > page
> > > > > > > > > > > program
> > > > > > > > > > > hardware
> > > > > > > > > > >   *			capabilities.
> > > > > > > > > > >   * @reads:		read capabilities
> > > > > > > > > > > ordered by
> > > > > > > > > > > priority:
> > > > > > > > > > > the
> > > > > > > > > > > higher index
> > > > > > > > > > > @@ -541,6 +546,7 @@ struct spi_nor_locking_ops {
> > > > > > > > > > >  struct spi_nor_flash_parameter {
> > > > > > > > > > >  	u64				size;
> > > > > > > > > > >  	u32				page_size;
> > > > > > > > > > > +	u16				n_sectors;
> > > > > > > > > > > 
> > > > > > > > > > >  	struct spi_nor_hwcaps		hwcaps;
> > > > > > > > > > >  	struct spi_nor_read_command	reads[SNOR_CMD_
> > > > > > > > > > > READ_MAX
> > > > > > > > > > > ];
> > > > > > > > > > > @@ -573,6 +579,7 @@ struct flash_info;
> > > > > > > > > > >   * @bouncebuf_size:	size of the bounce
> > > > > > > > > > > buffer
> > > > > > > > > > >   * @info:		spi-nor part JDEC MFR
> > > > > > > > > > > id and
> > > > > > > > > > > other info
> > > > > > > > > > >   * @page_size:		the page size of the
> > > > > > > > > > > SPI NOR
> > > > > > > > > > > + * @n_sector:		number of sectors
> > > > > > > > > > >   * @addr_width:		number of address bytes
> > > > > > > > > > >   * @erase_opcode:	the opcode for erasing
> > > > > > > > > > > a sector
> > > > > > > > > > >   * @read_opcode:	the read opcode
> > > > > > > > > > > @@ -599,6 +606,7 @@ struct spi_nor {
> > > > > > > > > > >  	size_t			bouncebuf_size;
> > > > > > > > > > >  	const struct flash_info	*info;
> > > > > > > > > > >  	u32			page_size;
> > > > > > > > > > > +	u16			n_sectors;
> > > > > > > > > > >  	u8			addr_width;
> > > > > > > > > > >  	u8			erase_opcode;
> > > > > > > > > > >  	u8			read_opcode;
> > > > > > > > > > > --
> > > > > > > > > > > 2.17.1
> > > > > > > > > > > 
> > > > > > > > > > > 
> > > > > > > > > > > _________________________________________________
> > > > > > > > > > > _____
> > > > > > > > > > > Linux MTD discussion mailing list
> > > > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > 
> > > > > > > 
> > > > > 
> > > > > 
> > > 
> > > 
https://protect2.fireeye.com/url?k=06b6dd5d-5b7d5a63-06b75612-0cc47a31309a-83164929001f7741&u=http://lists.infradead.org/mailman/listinfo/linux-mtd/
> > > > > > > > > > > 
> > > > > > > > > > 
> > > > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > 
> > > > > > 
> > > > 
> > > > 
> > > 
> > > Thanks,
> > > Jungseung Lee
> > > 
> 
> 


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Re: [SPAM] Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Vignesh Raghavendra]

Hi,

On 2/3/2020 8:08 PM, Michael Walle wrote:
> Am 2020-02-03 14:56, schrieb Vignesh Raghavendra:

[...]
>>
>> Flash devices have variable sector size, 64KB, 128KB or 256KB... While
>> mapping of number of sectors locked to BP bits is dependent on rules 1
>> to 3 you mentioned below, the size or area of flash protected depends on
>> sector size.
> 
> Is there any flash device which has another sector size != 64KiB for the
> BP bits?

I cannot seem to find BP scheme for Micron mt35x series but they all 
have 128KB sectors with 4 bit block protection scheme:
https://www.micron.com/-/media/client/global/documents/products/data-sheet/nor-flash/serial-nor/mt35x_xccela/die-rev-a/xccela_flash_memory_data_sheet_brief.pdf

Another example would be s25fl512s with 256KB sector with 3 bit BP:
https://www.cypress.com/file/177971/download

> 
>> So, the current formula in spi-nor.c (ignoring TB and other boilerplate):
>>
>> pow = ilog2(mtd->size) - ilog2(lock_len);
>> val = mask - (pow << shift);
>>
>> This works only for devices with 64KB sector size as 8MB flash with 64KB
>> sector size would have 128 sectors (BP0-2 => 0b111 => 2^7).
> 
> It also only works with flashes >= 4MiB. See fix below. And IMHO this is
> exactly
> the same "problem" the flashes with 4 BP bits have.
> 

Yes agree, but that patch is assumes sector size to be 64KB and 
once generalized would mostly be equivalent to below formula.

>> A more generic formula would be:
>>
>> Find n where 2^(n - 1) = len/sector-size
>> OR 2^ (n - 1) = len * n_sectors / mtd->size
>>
>> Which solves to:
>>
>> pow = ilog2(mtd->size) - ilog2(lock_len);
>> val = ilog2(nor->n_sectors) + 1 - pow;
>>
>> I see this is what Jungseung has tried to implement here.  Please
>> correct me if I got this wrong.
>>
>> This, combined with point (3) below should provide a generic
>> implementation that should support a wide variety of flashes.
>>
>> Of course, there are always exceptions and they need to be handled using
>> custom hooks.
>>
>> I don't have the patch that you shared with Jungseung. I would greatly
>> appreciate, if you and Jungseung could work on patch with above logic as
>> well as fixes to handle overflow case?
> 
> https://lore.kernel.org/linux-mtd/20200123170130.8289-1-michael@walle.cc/
> 
> As I said, that should work for both 3 and 4 bits. But be aware that this
> is an RFC and I've just tested it in in userspace, like the calculation
> of the bits and transferred that into the driver. So one would actually
> have to test that. But apparently no one had a even applied it.
> 

Sorry, I haven't looked at that patch. But I think better alternative would
be extend this patch to support overflow case.

Would it be possible to test this patch on flashes <32MBit, if you have
access to?

Regards
Vignesh

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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Tudor.Ambarus]

Hi,

On Monday, February 3, 2020 3:56:58 PM EET Vignesh Raghavendra wrote:
> >>>>>>>>> /*
> >>>>>>>>> * Need smallest pow such that:
> >>>>>>>>> *
> >>>>>>>>> @@ -1908,7 +1972,17 @@ static int stm_lock(struct
> >>>>>>>>> spi_nor
> >>>>>>>>> *nor,
> >>>>>>>>> loff_t ofs, uint64_t len)
> >>>>>>>>> *   pow = ceil(log2(size / len)) = log2(size)
> >>>>>>>>> -
> >>>>>>>>> floor(log2(len))
> >>>>>>>>> */
> >>>>>>>>> pow = ilog2(mtd->size) - ilog2(lock_len);
> >>>>>>>>> -     val = mask - (pow << SR_BP_SHIFT);
> >>>>>>>>> +
> >>>>>>>>> +     if (nor->flags & SNOR_F_HAS_SR_BP3) {
> >>>>>>>>> +             val = ilog2(nor->n_sectors) + 1 - pow;
> >>>>>>>> 
> >>>>>>>> Why do you use a new calculation here? As far as I can
> >>>>>>>> see,
> >>>>>>>> the
> >>>>>>>> method is
> >>>>>>>> the same except that is has one bit more. That also
> >>>>>>>> raises
> >>>>>>>> the
> >>>>>>>> question why
> >>>>>>>> n_sectors is now needed?
> 
> Flash devices have variable sector size, 64KB, 128KB or 256KB... While
> mapping of number of sectors locked to BP bits is dependent on rules 1
> to 3 you mentioned below, the size or area of flash protected depends on
> sector size.
> 
> So, the current formula in spi-nor.c (ignoring TB and other boilerplate):
> 
> pow = ilog2(mtd->size) - ilog2(lock_len);
> val = mask - (pow << shift);
> 
> This works only for devices with 64KB sector size as 8MB flash with 64KB
> sector size would have 128 sectors (BP0-2 => 0b111 => 2^7).
> 
> A more generic formula would be:
> 
> Find n where 2^(n - 1) = len/sector-size
> OR 2^ (n - 1) = len * n_sectors / mtd->size
> 
> Which solves to:
> 
> pow = ilog2(mtd->size) - ilog2(lock_len);
> val = ilog2(nor->n_sectors) + 1 - pow;

The current mainline locking support is limited. Michael spotted a good 
improvement, but I think there are still others that we should consider.

We should use a single formula, for all the BP cases. How about the following:

bp_slots_available = (bp_mask >> shift) + 1 - 2;
bp_slots_needed = ilog2(nor->info->n_sectors);

if (bp_slots_needed > bp_slots_available) {
	bp_slot_count = bp_slots_available;
	bp_min_slot_size = nor->info->n_sectors <<
		(bp_slots_needed - bp_slots_available);
} else {
	bp_slot_count = bp_slots_needed;
	bp_min_slot_size = mtd->size >> bp_block_count;
}

When both can_be_bottom and can_be_top are true, we prefer the top protection, 
which is incorrect/buggy/sub-optimal. If the received offset is not aligned to 
one of the start addresses of the bp slots, then we should up/down align the 
offset to the closest bp slot, depending on TB and which (top or bottom) fits 
better. Based on the updated offset and length we can compute the lock range, 
and after that:

n = ilog2(bp_lock_range/bp_min_slot_size) + 1;
val = mask - (n << shift);

Cheers,
ta



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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Hi Tudor and all,

Am 2020-02-07 13:17, schrieb Tudor.Ambarus@microchip.com:
> Hi,
> 
> On Monday, February 3, 2020 3:56:58 PM EET Vignesh Raghavendra wrote:
>> >>>>>>>>> /*
>> >>>>>>>>> * Need smallest pow such that:
>> >>>>>>>>> *
>> >>>>>>>>> @@ -1908,7 +1972,17 @@ static int stm_lock(struct
>> >>>>>>>>> spi_nor
>> >>>>>>>>> *nor,
>> >>>>>>>>> loff_t ofs, uint64_t len)
>> >>>>>>>>> *   pow = ceil(log2(size / len)) = log2(size)
>> >>>>>>>>> -
>> >>>>>>>>> floor(log2(len))
>> >>>>>>>>> */
>> >>>>>>>>> pow = ilog2(mtd->size) - ilog2(lock_len);
>> >>>>>>>>> -     val = mask - (pow << SR_BP_SHIFT);
>> >>>>>>>>> +
>> >>>>>>>>> +     if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> >>>>>>>>> +             val = ilog2(nor->n_sectors) + 1 - pow;
>> >>>>>>>>
>> >>>>>>>> Why do you use a new calculation here? As far as I can
>> >>>>>>>> see,
>> >>>>>>>> the
>> >>>>>>>> method is
>> >>>>>>>> the same except that is has one bit more. That also
>> >>>>>>>> raises
>> >>>>>>>> the
>> >>>>>>>> question why
>> >>>>>>>> n_sectors is now needed?
>> 
>> Flash devices have variable sector size, 64KB, 128KB or 256KB... While
>> mapping of number of sectors locked to BP bits is dependent on rules 1
>> to 3 you mentioned below, the size or area of flash protected depends 
>> on
>> sector size.
>> 
>> So, the current formula in spi-nor.c (ignoring TB and other 
>> boilerplate):
>> 
>> pow = ilog2(mtd->size) - ilog2(lock_len);
>> val = mask - (pow << shift);
>> 
>> This works only for devices with 64KB sector size as 8MB flash with 
>> 64KB
>> sector size would have 128 sectors (BP0-2 => 0b111 => 2^7).
>> 
>> A more generic formula would be:
>> 
>> Find n where 2^(n - 1) = len/sector-size
>> OR 2^ (n - 1) = len * n_sectors / mtd->size
>> 
>> Which solves to:
>> 
>> pow = ilog2(mtd->size) - ilog2(lock_len);
>> val = ilog2(nor->n_sectors) + 1 - pow;
> 
> The current mainline locking support is limited. Michael spotted a good
> improvement, but I think there are still others that we should 
> consider.

Sure, as I said my patch was just to show, that there is an underlying 
problem
and that we should not take the 4th BP bit to differentiate between the 
two
different formulas.

> We should use a single formula, for all the BP cases. How about the 
> following:
> 
> bp_slots_available = (bp_mask >> shift) + 1 - 2;
> bp_slots_needed = ilog2(nor->info->n_sectors);
> 
> if (bp_slots_needed > bp_slots_available) {
> 	bp_slot_count = bp_slots_available;
> 	bp_min_slot_size = nor->info->n_sectors <<
> 		(bp_slots_needed - bp_slots_available);

mhh, what is the unit of bp_min_slot_size? bytes or sectors? I guess it 
should
be bytes, eg for a 8MiB flash it would be 128kiB and for a 16MiB flash 
it would
be 256kiB (if there are 3 BP bits).


> } else {
> 	bp_slot_count = bp_slots_needed;
> 	bp_min_slot_size = mtd->size >> bp_block_count;

this is a complicated way of saying its the size of one sector, isn't 
it?
can't we use nor->info->sector_size here? Eg.

if (bp_slots_needed > bp_slots_available) {
	bp_slot_count = bp_slots_available;
	bp_min_slot_size = nor->info->sector_size <<
		(bp_slots_needed - bp_slots_available);
} else {
	bp_slot_count = bp_slots_needed;
  	bp_min_slot_size = nor->info->sector_size;
}



> }
> 
> When both can_be_bottom and can_be_top are true, we prefer the top 
> protection,
> which is incorrect/buggy/sub-optimal. If the received offset is not 
> aligned to
> one of the start addresses of the bp slots, then we should up/down 
> align the
> offset to the closest bp slot, depending on TB and which (top or 
> bottom) fits
> better. Based on the updated offset and length we can compute the lock 
> range,
> and after that:
> 
> n = ilog2(bp_lock_range/bp_min_slot_size) + 1;
> val = mask - (n << shift);

btw. we should catch the two special cases:
  - lock none -> 0 (that was already the case)
  - lock all -> all BP bits

The latter is important if "bp_slots_needed < bp_slots_available" 
because there
are multiple settings for protect all. Most flashes will define any 
remaining
setting for "protect all", but I've also seen flashes where the 
in-between ones
were undefined (not mentioned) and only the "all bit set" was protect 
all.


-michael

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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Tudor.Ambarus]

Hi, Michael,

On Monday, February 10, 2020 10:33:41 AM EET Michael Walle wrote:

cut

> > On Monday, February 3, 2020 3:56:58 PM EET Vignesh Raghavendra wrote:
> >> >>>>>>>>> /*
> >> >>>>>>>>> * Need smallest pow such that:
> >> >>>>>>>>> *
> >> >>>>>>>>> @@ -1908,7 +1972,17 @@ static int stm_lock(struct
> >> >>>>>>>>> spi_nor
> >> >>>>>>>>> *nor,
> >> >>>>>>>>> loff_t ofs, uint64_t len)
> >> >>>>>>>>> *   pow = ceil(log2(size / len)) = log2(size)
> >> >>>>>>>>> -
> >> >>>>>>>>> floor(log2(len))
> >> >>>>>>>>> */
> >> >>>>>>>>> pow = ilog2(mtd->size) - ilog2(lock_len);
> >> >>>>>>>>> -     val = mask - (pow << SR_BP_SHIFT);
> >> >>>>>>>>> +
> >> >>>>>>>>> +     if (nor->flags & SNOR_F_HAS_SR_BP3) {
> >> >>>>>>>>> +             val = ilog2(nor->n_sectors) + 1 - pow;
> >> >>>>>>>> 
> >> >>>>>>>> Why do you use a new calculation here? As far as I can
> >> >>>>>>>> see,
> >> >>>>>>>> the
> >> >>>>>>>> method is
> >> >>>>>>>> the same except that is has one bit more. That also
> >> >>>>>>>> raises
> >> >>>>>>>> the
> >> >>>>>>>> question why
> >> >>>>>>>> n_sectors is now needed?
> >> 
> >> Flash devices have variable sector size, 64KB, 128KB or 256KB... While
> >> mapping of number of sectors locked to BP bits is dependent on rules 1
> >> to 3 you mentioned below, the size or area of flash protected depends
> >> on
> >> sector size.
> >> 
> >> So, the current formula in spi-nor.c (ignoring TB and other
> >> boilerplate):
> >> 
> >> pow = ilog2(mtd->size) - ilog2(lock_len);
> >> val = mask - (pow << shift);
> >> 
> >> This works only for devices with 64KB sector size as 8MB flash with
> >> 64KB
> >> sector size would have 128 sectors (BP0-2 => 0b111 => 2^7).
> >> 
> >> A more generic formula would be:
> >> 
> >> Find n where 2^(n - 1) = len/sector-size
> >> OR 2^ (n - 1) = len * n_sectors / mtd->size
> >> 
> >> Which solves to:
> >> 
> >> pow = ilog2(mtd->size) - ilog2(lock_len);
> >> val = ilog2(nor->n_sectors) + 1 - pow;
> > 
> > The current mainline locking support is limited. Michael spotted a good
> > improvement, but I think there are still others that we should
> > consider.
> 
> Sure, as I said my patch was just to show, that there is an underlying
> problem
> and that we should not take the 4th BP bit to differentiate between the
> two
> different formulas.

Right, this is the goal.

Let me try to extend the description of the proposal.

> 
> > We should use a single formula, for all the BP cases. How about the
> > following:
> > 
> > bp_slots_available = (bp_mask >> shift) + 1 - 2;

This formula is derived from Michael's patch. 

A slot (to me) is a horizontal line in the Memory protection table. Maybe we 
can find a better/standardized name for this.

So for BP0-2, bp_slots_available = 6, and for BP0-3, bp_slots_available = 14. 
Notice that I stripped the two special cases: lock none and lock all.

> > bp_slots_needed = ilog2(nor->info->n_sectors);

With bp_slots_needed I tried to describe how many slots are needed if the 
protected density for the first slot is at minimum (sector size).

> > 
> > if (bp_slots_needed > bp_slots_available) {
> > 
> >       bp_slot_count = bp_slots_available;
> >       bp_min_slot_size = nor->info->n_sectors <<
> >       
> >               (bp_slots_needed - bp_slots_available);
> 
> mhh, what is the unit of bp_min_slot_size? bytes or sectors? I guess it
> should

It's bytes. Take a look at W25Q128JV. The sector size for this flash is 
64KByte. The flash has 256 sectors. For this specific case:
	bp_slots_available = 6;
	bp_slots_needed = 8;

The if condition is true, so
	bp_slot_count = 6;
	bp_min_slot_size = 64k << (8 - 6); //256k

which is exactly the protected density for the first slot. The protected 
densities of the other slots can be computed by multiplying with powers of 2.

> be bytes, eg for a 8MiB flash it would be 128kiB and for a 16MiB flash
> it would
> be 256kiB (if there are 3 BP bits).
> 
> > } else {
> > 
> >       bp_slot_count = bp_slots_needed;
> >       bp_min_slot_size = mtd->size >> bp_block_count;

typo: s/bp_block_count/bp_slot_count
> 
> this is a complicated way of saying its the size of one sector, isn't
> it?
> can't we use nor->info->sector_size here? Eg.
> 
> if (bp_slots_needed > bp_slots_available) {
>         bp_slot_count = bp_slots_available;
>         bp_min_slot_size = nor->info->sector_size <<
>                 (bp_slots_needed - bp_slots_available);
> } else {
>         bp_slot_count = bp_slots_needed;
>         bp_min_slot_size = nor->info->sector_size;
> }

you're right, we're in the else case, where the assumption that the minimum 
protected density is sector size is true, we can use directly nor->info-
>sector_size.

> 
> > }
> > 
> > When both can_be_bottom and can_be_top are true, we prefer the top
> > protection,
> > which is incorrect/buggy/sub-optimal. If the received offset is not
> > aligned to
> > one of the start addresses of the bp slots, then we should up/down
> > align the
> > offset to the closest bp slot, depending on TB and which (top or
> > bottom) fits
> > better. Based on the updated offset and length we can compute the lock
> > range,
> > and after that:
> > 
> > n = ilog2(bp_lock_range/bp_min_slot_size) + 1;
> > val = mask - (n << shift);
> 
> btw. we should catch the two special cases:
>   - lock none -> 0 (that was already the case)
>   - lock all -> all BP bits
> 
> The latter is important if "bp_slots_needed < bp_slots_available"
> because there
> are multiple settings for protect all. Most flashes will define any
> remaining
> setting for "protect all", but I've also seen flashes where the
> in-between ones
> were undefined (not mentioned) and only the "all bit set" was protect
> all.

This case is addressed by using bp_slot_count and bp_slots_available. We're in 
the else case from above. From bp_slot_count up to the bp_slots_available, 
those slots are "protect all".

Cheers,
ta


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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Tudor.Ambarus]

On Monday, February 10, 2020 11:47:23 AM EET Tudor Ambarus wrote:
> > btw. we should catch the two special cases:
> > - lock none -> 0 (that was already the case)
> > - lock all -> all BP bits
> > 
> > The latter is important if "bp_slots_needed < bp_slots_available"
> > because there
> > are multiple settings for protect all. Most flashes will define any
> > remaining
> > setting for "protect all", but I've also seen flashes where the
> > in-between ones
> > were undefined (not mentioned) and only the "all bit set" was protect
> > all.

I re-read this. Do you have such an example of flash? Aren't the BP bits in 
this case marked with "X", i.e. don't care? If not, probably we can mask out 
those undefined slots.
> 
> This case is addressed by using bp_slot_count and bp_slots_available. We're
> in the else case from above. From bp_slot_count up to the
> bp_slots_available, those slots are "protect all".




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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Am 2020-02-10 10:59, schrieb Tudor.Ambarus@microchip.com:
> On Monday, February 10, 2020 11:47:23 AM EET Tudor Ambarus wrote:
>> > btw. we should catch the two special cases:
>> > - lock none -> 0 (that was already the case)
>> > - lock all -> all BP bits
>> >
>> > The latter is important if "bp_slots_needed < bp_slots_available"
>> > because there
>> > are multiple settings for protect all. Most flashes will define any
>> > remaining
>> > setting for "protect all", but I've also seen flashes where the
>> > in-between ones
>> > were undefined (not mentioned) and only the "all bit set" was protect
>> > all.
> 
> I re-read this. Do you have such an example of flash? Aren't the BP 
> bits in
> this case marked with "X", i.e. don't care? If not, probably we can 
> mask out
> those undefined slots.

There was definetly some datasheet where the remaining ones wasn't 
described
_and_ there was no X (don't care) bits. Unfortunately, I don't find it 
right
now. That datasheed made me wonder what the other "undefinded" cases 
would be.
Probably it will also be "protect all"; I just mentioned it because it 
would
be an easy special case to handle. I don't think we should mask out 
anything,
either use the slot in between (ie the one which the formula gives us) 
to
protect all or use the largest setting (ie [TB3 |] TB2 | TB1 | TB0). And
given the reasons above, I'd prefer the latter.

>> 
>> This case is addressed by using bp_slot_count and bp_slots_available. 
>> We're
>> in the else case from above. From bp_slot_count up to the
>> bp_slots_available, those slots are "protect all".

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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Tudor.Ambarus]

On Monday, February 10, 2020 12:40:59 PM EET Michael Walle wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the
> content is safe
> Am 2020-02-10 10:59, schrieb Tudor.Ambarus@microchip.com:
> > On Monday, February 10, 2020 11:47:23 AM EET Tudor Ambarus wrote:
> >> > btw. we should catch the two special cases:
> >> > - lock none -> 0 (that was already the case)
> >> > - lock all -> all BP bits
> >> > 
> >> > The latter is important if "bp_slots_needed < bp_slots_available"
> >> > because there
> >> > are multiple settings for protect all. Most flashes will define any
> >> > remaining
> >> > setting for "protect all", but I've also seen flashes where the
> >> > in-between ones
> >> > were undefined (not mentioned) and only the "all bit set" was protect
> >> > all.
> > 
> > I re-read this. Do you have such an example of flash? Aren't the BP
> > bits in
> > this case marked with "X", i.e. don't care? If not, probably we can
> > mask out
> > those undefined slots.
> 
> There was definetly some datasheet where the remaining ones wasn't
> described
> _and_ there was no X (don't care) bits. Unfortunately, I don't find it
> right
> now. That datasheed made me wonder what the other "undefinded" cases
> would be.
> Probably it will also be "protect all"; I just mentioned it because it
> would
> be an easy special case to handle. I don't think we should mask out
> anything,
> either use the slot in between (ie the one which the formula gives us)
> to
> protect all or use the largest setting (ie [TB3 |] TB2 | TB1 | TB0). And
> given the reasons above, I'd prefer the latter.

I'm fine with using the largest setting, but we'll need the proof before going 
this way.

Cheers,
ta
> 
> >> This case is addressed by using bp_slot_count and bp_slots_available.
> >> We're
> >> in the else case from above. From bp_slot_count up to the
> >> bp_slots_available, those slots are "protect all".




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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Am 2020-02-10 12:27, schrieb Tudor.Ambarus@microchip.com:
> On Monday, February 10, 2020 12:40:59 PM EET Michael Walle wrote:
>> EXTERNAL EMAIL: Do not click links or open attachments unless you know 
>> the
>> content is safe
>> Am 2020-02-10 10:59, schrieb Tudor.Ambarus@microchip.com:
>> > On Monday, February 10, 2020 11:47:23 AM EET Tudor Ambarus wrote:
>> >> > btw. we should catch the two special cases:
>> >> > - lock none -> 0 (that was already the case)
>> >> > - lock all -> all BP bits
>> >> >
>> >> > The latter is important if "bp_slots_needed < bp_slots_available"
>> >> > because there
>> >> > are multiple settings for protect all. Most flashes will define any
>> >> > remaining
>> >> > setting for "protect all", but I've also seen flashes where the
>> >> > in-between ones
>> >> > were undefined (not mentioned) and only the "all bit set" was protect
>> >> > all.
>> >
>> > I re-read this. Do you have such an example of flash? Aren't the BP
>> > bits in
>> > this case marked with "X", i.e. don't care? If not, probably we can
>> > mask out
>> > those undefined slots.
>> 
>> There was definetly some datasheet where the remaining ones wasn't
>> described
>> _and_ there was no X (don't care) bits. Unfortunately, I don't find it
>> right
>> now. That datasheed made me wonder what the other "undefinded" cases
>> would be.
>> Probably it will also be "protect all"; I just mentioned it because it
>> would
>> be an easy special case to handle. I don't think we should mask out
>> anything,
>> either use the slot in between (ie the one which the formula gives us)
>> to
>> protect all or use the largest setting (ie [TB3 |] TB2 | TB1 | TB0). 
>> And
>> given the reasons above, I'd prefer the latter.
> 
> I'm fine with using the largest setting, but we'll need the proof 
> before going
> this way.

have a look at 7.1.11:
   https://www.winbond.com/resource-files/w25q80dv_revg_07212015.pdf

BP[2:0]=0b101 and 0b110 is not defined.

-michael

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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Tudor.Ambarus]

On Monday, February 10, 2020 2:14:48 PM EET Michael Walle wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the
> content is safe
> Am 2020-02-10 12:27, schrieb Tudor.Ambarus@microchip.com:
> > On Monday, February 10, 2020 12:40:59 PM EET Michael Walle wrote:
> >> EXTERNAL EMAIL: Do not click links or open attachments unless you know
> >> the
> >> content is safe
> >> 
> >> Am 2020-02-10 10:59, schrieb Tudor.Ambarus@microchip.com:
> >> > On Monday, February 10, 2020 11:47:23 AM EET Tudor Ambarus wrote:
> >> >> > btw. we should catch the two special cases:
> >> >> > - lock none -> 0 (that was already the case)
> >> >> > - lock all -> all BP bits
> >> >> > 
> >> >> > The latter is important if "bp_slots_needed < bp_slots_available"
> >> >> > because there
> >> >> > are multiple settings for protect all. Most flashes will define any
> >> >> > remaining
> >> >> > setting for "protect all", but I've also seen flashes where the
> >> >> > in-between ones
> >> >> > were undefined (not mentioned) and only the "all bit set" was
> >> >> > protect
> >> >> > all.
> >> > 
> >> > I re-read this. Do you have such an example of flash? Aren't the BP
> >> > bits in
> >> > this case marked with "X", i.e. don't care? If not, probably we can
> >> > mask out
> >> > those undefined slots.
> >> 
> >> There was definetly some datasheet where the remaining ones wasn't
> >> described
> >> _and_ there was no X (don't care) bits. Unfortunately, I don't find it
> >> right
> >> now. That datasheed made me wonder what the other "undefinded" cases
> >> would be.
> >> Probably it will also be "protect all"; I just mentioned it because it
> >> would
> >> be an easy special case to handle. I don't think we should mask out
> >> anything,
> >> either use the slot in between (ie the one which the formula gives us)
> >> to
> >> protect all or use the largest setting (ie [TB3 |] TB2 | TB1 | TB0).
> >> And
> >> given the reasons above, I'd prefer the latter.
> > 
> > I'm fine with using the largest setting, but we'll need the proof
> > before going
> > this way.
> 
> have a look at 7.1.11:
>    https://www.winbond.com/resource-files/w25q80dv_revg_07212015.pdf
> 
> BP[2:0]=0b101 and 0b110 is not defined.
> 

Good enough for me. Thanks, Michael!




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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Hi Tudor,

Am 2020-02-10 10:47, schrieb Tudor.Ambarus@microchip.com:
> Hi, Michael,
> 
> On Monday, February 10, 2020 10:33:41 AM EET Michael Walle wrote:
> 
> cut
> 
>> > On Monday, February 3, 2020 3:56:58 PM EET Vignesh Raghavendra wrote:
>> >> >>>>>>>>> /*
>> >> >>>>>>>>> * Need smallest pow such that:
>> >> >>>>>>>>> *
>> >> >>>>>>>>> @@ -1908,7 +1972,17 @@ static int stm_lock(struct
>> >> >>>>>>>>> spi_nor
>> >> >>>>>>>>> *nor,
>> >> >>>>>>>>> loff_t ofs, uint64_t len)
>> >> >>>>>>>>> *   pow = ceil(log2(size / len)) = log2(size)
>> >> >>>>>>>>> -
>> >> >>>>>>>>> floor(log2(len))
>> >> >>>>>>>>> */
>> >> >>>>>>>>> pow = ilog2(mtd->size) - ilog2(lock_len);
>> >> >>>>>>>>> -     val = mask - (pow << SR_BP_SHIFT);
>> >> >>>>>>>>> +
>> >> >>>>>>>>> +     if (nor->flags & SNOR_F_HAS_SR_BP3) {
>> >> >>>>>>>>> +             val = ilog2(nor->n_sectors) + 1 - pow;
>> >> >>>>>>>>
>> >> >>>>>>>> Why do you use a new calculation here? As far as I can
>> >> >>>>>>>> see,
>> >> >>>>>>>> the
>> >> >>>>>>>> method is
>> >> >>>>>>>> the same except that is has one bit more. That also
>> >> >>>>>>>> raises
>> >> >>>>>>>> the
>> >> >>>>>>>> question why
>> >> >>>>>>>> n_sectors is now needed?
>> >>
>> >> Flash devices have variable sector size, 64KB, 128KB or 256KB... While
>> >> mapping of number of sectors locked to BP bits is dependent on rules 1
>> >> to 3 you mentioned below, the size or area of flash protected depends
>> >> on
>> >> sector size.
>> >>
>> >> So, the current formula in spi-nor.c (ignoring TB and other
>> >> boilerplate):
>> >>
>> >> pow = ilog2(mtd->size) - ilog2(lock_len);
>> >> val = mask - (pow << shift);
>> >>
>> >> This works only for devices with 64KB sector size as 8MB flash with
>> >> 64KB
>> >> sector size would have 128 sectors (BP0-2 => 0b111 => 2^7).
>> >>
>> >> A more generic formula would be:
>> >>
>> >> Find n where 2^(n - 1) = len/sector-size
>> >> OR 2^ (n - 1) = len * n_sectors / mtd->size
>> >>
>> >> Which solves to:
>> >>
>> >> pow = ilog2(mtd->size) - ilog2(lock_len);
>> >> val = ilog2(nor->n_sectors) + 1 - pow;
>> >
>> > The current mainline locking support is limited. Michael spotted a good
>> > improvement, but I think there are still others that we should
>> > consider.
>> 
>> Sure, as I said my patch was just to show, that there is an underlying
>> problem
>> and that we should not take the 4th BP bit to differentiate between 
>> the
>> two
>> different formulas.
> 
> Right, this is the goal.
> 
> Let me try to extend the description of the proposal.
> 
>> 
>> > We should use a single formula, for all the BP cases. How about the
>> > following:
>> >
>> > bp_slots_available = (bp_mask >> shift) + 1 - 2;
> 
> This formula is derived from Michael's patch.
> 
> A slot (to me) is a horizontal line in the Memory protection table. 
> Maybe we
> can find a better/standardized name for this.
> 
> So for BP0-2, bp_slots_available = 6, and for BP0-3, bp_slots_available 
> = 14.
> Notice that I stripped the two special cases: lock none and lock all.
> 
>> > bp_slots_needed = ilog2(nor->info->n_sectors);
> 
> With bp_slots_needed I tried to describe how many slots are needed if 
> the
> protected density for the first slot is at minimum (sector size).
> 
>> >
>> > if (bp_slots_needed > bp_slots_available) {
>> >
>> >       bp_slot_count = bp_slots_available;
>> >       bp_min_slot_size = nor->info->n_sectors <<
>> >
>> >               (bp_slots_needed - bp_slots_available);
>> 
>> mhh, what is the unit of bp_min_slot_size? bytes or sectors? I guess 
>> it
>> should
> 
> It's bytes. Take a look at W25Q128JV. The sector size for this flash is
> 64KByte. The flash has 256 sectors. For this specific case:
> 	bp_slots_available = 6;
> 	bp_slots_needed = 8;
> 
> The if condition is true, so
> 	bp_slot_count = 6;
> 	bp_min_slot_size = 64k << (8 - 6); //256k

But nor->info->n_sectors is not 64k, its 256. Do you mean sector_size 
(like in
my example below? Then we are on the same page ;)


> which is exactly the protected density for the first slot. The 
> protected
> densities of the other slots can be computed by multiplying with powers 
> of 2.
> 
>> be bytes, eg for a 8MiB flash it would be 128kiB and for a 16MiB flash
>> it would
>> be 256kiB (if there are 3 BP bits).
>> 
>> > } else {
>> >
>> >       bp_slot_count = bp_slots_needed;
>> >       bp_min_slot_size = mtd->size >> bp_block_count;
> 
> typo: s/bp_block_count/bp_slot_count
>> 
>> this is a complicated way of saying its the size of one sector, isn't
>> it?
>> can't we use nor->info->sector_size here? Eg.
>> 
>> if (bp_slots_needed > bp_slots_available) {
>>         bp_slot_count = bp_slots_available;
>>         bp_min_slot_size = nor->info->sector_size <<
>>                 (bp_slots_needed - bp_slots_available);
>> } else {
>>         bp_slot_count = bp_slots_needed;
>>         bp_min_slot_size = nor->info->sector_size;
>> }
> 
> you're right, we're in the else case, where the assumption that the 
> minimum
> protected density is sector size is true, we can use directly 
> nor->info-
>> sector_size.
> 
>> 
>> > }
>> >
>> > When both can_be_bottom and can_be_top are true, we prefer the top
>> > protection,
>> > which is incorrect/buggy/sub-optimal. If the received offset is not
>> > aligned to
>> > one of the start addresses of the bp slots, then we should up/down
>> > align the
>> > offset to the closest bp slot, depending on TB and which (top or
>> > bottom) fits
>> > better. Based on the updated offset and length we can compute the lock
>> > range,
>> > and after that:
>> >
>> > n = ilog2(bp_lock_range/bp_min_slot_size) + 1;
>> > val = mask - (n << shift);
>> 
>> btw. we should catch the two special cases:
>>   - lock none -> 0 (that was already the case)
>>   - lock all -> all BP bits
>> 
>> The latter is important if "bp_slots_needed < bp_slots_available"
>> because there
>> are multiple settings for protect all. Most flashes will define any
>> remaining
>> setting for "protect all", but I've also seen flashes where the
>> in-between ones
>> were undefined (not mentioned) and only the "all bit set" was protect
>> all.
> 
> This case is addressed by using bp_slot_count and bp_slots_available. 
> We're in
> the else case from above. From bp_slot_count up to the 
> bp_slots_available,
> those slots are "protect all".

-michael

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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Tudor.Ambarus]

On Monday, February 10, 2020 12:29:34 PM EET Michael Walle wrote:
> > It's bytes. Take a look at W25Q128JV. The sector size for this flash is
> > 64KByte. The flash has 256 sectors. For this specific case:
> > bp_slots_available = 6;
> > bp_slots_needed = 8;
> > 
> > The if condition is true, so
> > bp_slot_count = 6;
> > bp_min_slot_size = 64k << (8 - 6); //256k
> 
> But nor->info->n_sectors is not 64k, its 256. Do you mean sector_size
> (like in
> my example below? Then we are on the same page 

Indeed, there is a typo in the pseudo code; I'm happy that the example is 
correct at least. I meant sector_size, not sectors. Now we should exercise the 
logic to all the known (corner) cases. Maybe Jungseung will tell us if he 
spots a flaw in the overall logic.

Cheers,
ta


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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Hi, Tudor and all

2020-02-10 (Mon), 11:26 +0000, Tudor.Ambarus@microchip.com:
> On Monday, February 10, 2020 12:29:34 PM EET Michael Walle wrote:
> > > It's bytes. Take a look at W25Q128JV. The sector size for this
> > > flash is
> > > 64KByte. The flash has 256 sectors. For this specific case:
> > > bp_slots_available = 6;
> > > bp_slots_needed = 8;
> > > 
> > > The if condition is true, so
> > > bp_slot_count = 6;
> > > bp_min_slot_size = 64k << (8 - 6); //256k
> > 
> > But nor->info->n_sectors is not 64k, its 256. Do you mean
> > sector_size
> > (like in
> > my example below? Then we are on the same page 
> 
> Indeed, there is a typo in the pseudo code; I'm happy that the
> example is 
> correct at least. I meant sector_size, not sectors. Now we should
> exercise the 
> logic to all the known (corner) cases. Maybe Jungseung will tell us
> if he 
> spots a flaw in the overall logic.
> 

I didn't find any flaw in this logic. But IMHO for the pseudo code.

bp_slots_available = (bp_mask >> shift) + 1 - 2;
bp_slots_needed = ilog2(nor->info->n_sectors);
 
if (bp_slots_needed > bp_slots_available) {  
    bp_slot_count = bp_slots_available;
    bp_min_slot_size = nor->info->sector_size <<
        (bp_slots_needed - bp_slots_available);
} else {
    bp_slot_count = bp_slots_needed;
    bp_min_slot_size = mtd->size >> bp_slot_count;
}

Probably we can use directly nor->info->sector_size for bp_min_slot_
size.

sector_size x n_sectors = mtd->size
mtd->size / n_sectors = mtd->size >>
ilog2(n_sectors) = sector_size

bp_slot_count is equal to log2(n_sectors) now so if we can trust the
value, we can also trust sector_size.

After change it,

if (bp_slots_needed > bp_slots_available)
    bp_min_slot_size = nor->info->sector_size <<
        (bp_slots_needed - bp_slots_available);
else
    bp_min_slot_size = nor->info->sector_size;

This is a comment from my previous mail.
> > The exact fact is that locks operate in two different ways
> > according to flash model.
> > 
> > (1) the smallest protected portion is fixed.
> >     for BP0-2 : 1/64
> >     for BP0-1 : 1/4
> > (2) the smallest protected portion is inversely propotional with
> > number of sectors.

(1) - if the slot is insufficient.
(2) - if the slot is sufficient.

From the fact, that could be rewritten like below. I think it's more
intuitive one.

if (bp_slots_needed > bp_slots_available)    // (1)
    bp_min_slot_size = mtd->size >> bp_slots_available;
else                                         // (2)
    bp_min_slot_size = nor->info->sector_size;

We could also find a few flashes that does not following the overall
logic. For example, "en25qh256" and "en25qh16" which was manufactured
by EON. They are always following way (2) no matter what the number of
slot is. It seems that it could be handled like below with custom hook
later.

if (bp_slots_needed < bp_slots_available || force)
    bp_min_slot_size = nor->info->sector_size;
else
    bp_min_slot_size = mtd->size >> bp_slots_available;

> Cheers,
> ta
> 

Thanks,



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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Am 2020-02-19 11:50, schrieb Jungseung Lee:
> Hi, Tudor and all
> 
> 2020-02-10 (Mon), 11:26 +0000, Tudor.Ambarus@microchip.com:
> We could also find a few flashes that does not following the overall
> logic. For example, "en25qh256" and "en25qh16" which was manufactured
> by EON. They are always following way (2) no matter what the number of
> slot is. It seems that it could be handled like below with custom hook
> later.

For these two flashes, BP3 is just the TB bit. So it should already work 
with the current logic.

-michael


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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Hi,

2020-02-19 (Wed), 12:08 +0100, Michael Walle:
> Am 2020-02-19 11:50, schrieb Jungseung Lee:
> > Hi, Tudor and all
> > 
> > 2020-02-10 (Mon), 11:26 +0000, Tudor.Ambarus@microchip.com:
> > We could also find a few flashes that does not following the
> > overall
> > logic. For example, "en25qh256" and "en25qh16" which was
> > manufactured
> > by EON. They are always following way (2) no matter what the number
> > of
> > slot is. It seems that it could be handled like below with custom
> > hook
> > later.
> 
> For these two flashes, BP3 is just the TB bit. So it should already
> work 
> with the current logic.
> 

Refer to what I mentioned before in the mail I talked with you.

>>It is mixed. Let's compare "en25qh128" from EON with "w25q128jv" from
>>Winbond. They have the same capacity(128MBit) and also supporting
>>3bit
>>block protection. (Note that the named BP3 bit of "en25qh128" is
>>working exactly same with T/B bit.)

>>"en25qh128" is following (2) and "w25q128jv" is following (1). It
>>seems
>>impossible to distinguish them by the flash size or the number of
>>protection bits. 

> -michael
> 
> 

Thanks,


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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Am 19. Februar 2020 12:23:24 MEZ schrieb Jungseung Lee <js07.lee@samsung.com>:
>Hi,
>
>2020-02-19 (Wed), 12:08 +0100, Michael Walle:
>> Am 2020-02-19 11:50, schrieb Jungseung Lee:
>> > Hi, Tudor and all
>> > 
>> > 2020-02-10 (Mon), 11:26 +0000, Tudor.Ambarus@microchip.com:
>> > We could also find a few flashes that does not following the
>> > overall
>> > logic. For example, "en25qh256" and "en25qh16" which was
>> > manufactured
>> > by EON. They are always following way (2) no matter what the number
>> > of
>> > slot is. It seems that it could be handled like below with custom
>> > hook
>> > later.
>> 
>> For these two flashes, BP3 is just the TB bit. So it should already
>> work 
>> with the current logic.
>> 
>
>Refer to what I mentioned before in the mail I talked with you.
>
>>>It is mixed. Let's compare "en25qh128" from EON with "w25q128jv" from
>>>Winbond. They have the same capacity(128MBit) and also supporting
>>>3bit
>>>block protection. (Note that the named BP3 bit of "en25qh128" is
>>>working exactly same with T/B bit.)
>
>>>"en25qh128" is following (2) and "w25q128jv" is following (1). It
>>>seems
>>>impossible to distinguish them by the flash size or the number of
>>>protection bits. 

Oh, correct. but why should it then be a problem? Its like all, the other flashes.

-michael 

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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Michael Walle]

Am 2020-02-19 11:50, schrieb Jungseung Lee:
> Hi, Tudor and all
> 
> 2020-02-10 (Mon), 11:26 +0000, Tudor.Ambarus@microchip.com:
>> On Monday, February 10, 2020 12:29:34 PM EET Michael Walle wrote:
>> > > It's bytes. Take a look at W25Q128JV. The sector size for this
>> > > flash is
>> > > 64KByte. The flash has 256 sectors. For this specific case:
>> > > bp_slots_available = 6;
>> > > bp_slots_needed = 8;
>> > >
>> > > The if condition is true, so
>> > > bp_slot_count = 6;
>> > > bp_min_slot_size = 64k << (8 - 6); //256k
>> >
>> > But nor->info->n_sectors is not 64k, its 256. Do you mean
>> > sector_size
>> > (like in
>> > my example below? Then we are on the same page
>> 
>> Indeed, there is a typo in the pseudo code; I'm happy that the
>> example is
>> correct at least. I meant sector_size, not sectors. Now we should
>> exercise the
>> logic to all the known (corner) cases. Maybe Jungseung will tell us
>> if he
>> spots a flaw in the overall logic.
>> 
> 
> I didn't find any flaw in this logic. But IMHO for the pseudo code.
> 
> bp_slots_available = (bp_mask >> shift) + 1 - 2;
> bp_slots_needed = ilog2(nor->info->n_sectors);
> 
> if (bp_slots_needed > bp_slots_available) {
>     bp_slot_count = bp_slots_available;
>     bp_min_slot_size = nor->info->sector_size <<
>         (bp_slots_needed - bp_slots_available);
> } else {
>     bp_slot_count = bp_slots_needed;
>     bp_min_slot_size = mtd->size >> bp_slot_count;
> }
> 
> Probably we can use directly nor->info->sector_size for bp_min_slot_
> size.
> 
> sector_size x n_sectors = mtd->size
> mtd->size / n_sectors = mtd->size >>
> ilog2(n_sectors) = sector_size
> 
> bp_slot_count is equal to log2(n_sectors) now so if we can trust the
> value, we can also trust sector_size.
> 
> After change it,
> 
> if (bp_slots_needed > bp_slots_available)
>     bp_min_slot_size = nor->info->sector_size <<
>         (bp_slots_needed - bp_slots_available);
> else
>     bp_min_slot_size = nor->info->sector_size

Yes, thats what I pointed out in my previous mail, too. So I guess we
agree on that.

> This is a comment from my previous mail.
>> > The exact fact is that locks operate in two different ways
>> > according to flash model.
>> >
>> > (1) the smallest protected portion is fixed.
>> >     for BP0-2 : 1/64
>> >     for BP0-1 : 1/4
>> > (2) the smallest protected portion is inversely propotional with
>> > number of sectors.

Again. please don't consider the ratio of the protected area to the 
flash size.
This is only the result of applying the sector size and IMHO really bad 
for
understanding. Use the number of protected sectors. Thus your (2) is 
actually
always one sector (as you've already pointed out above).

> (1) - if the slot is insufficient.
> (2) - if the slot is sufficient.
> 
> From the fact, that could be rewritten like below. I think it's more
> intuitive one.
> 
> if (bp_slots_needed > bp_slots_available)    // (1)
>     bp_min_slot_size = mtd->size >> bp_slots_available;

Given the reasoning above, I'd prefer having the number of sectors and 
thus
the sector_size. Eg. keep the following

     bp_min_slot_size = nor->info->sector_size <<
          (bp_slots_needed - bp_slots_available);


> else                                         // (2)
>     bp_min_slot_size = nor->info->sector_size;
> 
> We could also find a few flashes that does not following the overall
> logic. For example, "en25qh256" and "en25qh16" which was manufactured
> by EON. They are always following way (2) no matter what the number of
> slot is. It seems that it could be handled like below with custom hook
> later.
> 
> if (bp_slots_needed < bp_slots_available || force)

For the en25qh16 the "bp_slots_needed < bp_slots_available" is already
true, isn't it?
But good catch for the en25qh256. IMHO the rework of the BP bits should 
already
add a flag (together with a reference to this flash) so this information
is not lost. what about sth like MIN_LOCK_SIZE_IS_ONE_SECTOR.

-michael

>     bp_min_slot_size = nor->info->sector_size;
> else
>     bp_min_slot_size = mtd->size >> bp_slots_available;
> 
>> Cheers,
>> ta
>> 
> 
> Thanks,

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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Tudor.Ambarus]

On Thursday, February 20, 2020 9:09:03 PM EET Michael Walle wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the
> content is safe
> Am 2020-02-19 11:50, schrieb Jungseung Lee:
> > Hi, Tudor and all

Hi, Jungseung, Michael,

> > 
> > 2020-02-10 (Mon), 11:26 +0000, Tudor.Ambarus@microchip.com:
> >> On Monday, February 10, 2020 12:29:34 PM EET Michael Walle wrote:
> >> > > It's bytes. Take a look at W25Q128JV. The sector size for this
> >> > > flash is
> >> > > 64KByte. The flash has 256 sectors. For this specific case:
> >> > > bp_slots_available = 6;
> >> > > bp_slots_needed = 8;
> >> > > 
> >> > > The if condition is true, so
> >> > > bp_slot_count = 6;
> >> > > bp_min_slot_size = 64k << (8 - 6); //256k
> >> > 
> >> > But nor->info->n_sectors is not 64k, its 256. Do you mean
> >> > sector_size
> >> > (like in
> >> > my example below? Then we are on the same page
> >> 
> >> Indeed, there is a typo in the pseudo code; I'm happy that the
> >> example is
> >> correct at least. I meant sector_size, not sectors. Now we should
> >> exercise the
> >> logic to all the known (corner) cases. Maybe Jungseung will tell us
> >> if he
> >> spots a flaw in the overall logic.
> > 
> > I didn't find any flaw in this logic. But IMHO for the pseudo code.
> > 
> > bp_slots_available = (bp_mask >> shift) + 1 - 2;
> > bp_slots_needed = ilog2(nor->info->n_sectors);
> > 
> > if (bp_slots_needed > bp_slots_available) {
> > 
> >     bp_slot_count = bp_slots_available;
> >     bp_min_slot_size = nor->info->sector_size <<
> >     
> >         (bp_slots_needed - bp_slots_available);
> > 
> > } else {
> > 
> >     bp_slot_count = bp_slots_needed;
> >     bp_min_slot_size = mtd->size >> bp_slot_count;
> > 
> > }
> > 
> > Probably we can use directly nor->info->sector_size for bp_min_slot_
> > size.
> > 
> > sector_size x n_sectors = mtd->size
> > mtd->size / n_sectors = mtd->size >>
> > ilog2(n_sectors) = sector_size
> > 
> > bp_slot_count is equal to log2(n_sectors) now so if we can trust the
> > value, we can also trust sector_size.
> > 
> > After change it,
> > 
> > if (bp_slots_needed > bp_slots_available)
> > 
> >     bp_min_slot_size = nor->info->sector_size <<
> >     
> >         (bp_slots_needed - bp_slots_available);
> > 
> > else
> > 
> >     bp_min_slot_size = nor->info->sector_size
> 
> Yes, thats what I pointed out in my previous mail, too. So I guess we
> agree on that.

Yes, agreed on this.

> 
> > This is a comment from my previous mail.
> > 
> >> > The exact fact is that locks operate in two different ways
> >> > according to flash model.
> >> > 
> >> > (1) the smallest protected portion is fixed.
> >> > 
> >> >     for BP0-2 : 1/64
> >> >     for BP0-1 : 1/4
> >> > 
> >> > (2) the smallest protected portion is inversely propotional with
> >> > number of sectors.
> 
> Again. please don't consider the ratio of the protected area to the
> flash size.
> This is only the result of applying the sector size and IMHO really bad
> for
> understanding. Use the number of protected sectors. Thus your (2) is
> actually
> always one sector (as you've already pointed out above).
> 
> > (1) - if the slot is insufficient.
> > (2) - if the slot is sufficient.
> > 
> > From the fact, that could be rewritten like below. I think it's more
> > intuitive one.
> > 
> > if (bp_slots_needed > bp_slots_available)    // (1)
> > 
> >     bp_min_slot_size = mtd->size >> bp_slots_available;
> 
> Given the reasoning above, I'd prefer having the number of sectors and
> thus
> the sector_size. Eg. keep the following
> 
>      bp_min_slot_size = nor->info->sector_size <<
>           (bp_slots_needed - bp_slots_available);

Both variants seem to work, this is a matter of taste. I would also use the 
sector_size variant because it emphasizes that the sector size is not enough
large to be used as the min protected density. And it is in correlation with 
the else case, it's easier (for me) to read it.

> 
> > else                                         // (2)
> > 
> >     bp_min_slot_size = nor->info->sector_size;
> > 
> > We could also find a few flashes that does not following the overall
> > logic. For example, "en25qh256" and "en25qh16" which was manufactured

oh, the horror! :)

> > by EON. They are always following way (2) no matter what the number of
> > slot is. It seems that it could be handled like below with custom hook
> > later.
> > 
> > if (bp_slots_needed < bp_slots_available || force)
> 
> For the en25qh16 the "bp_slots_needed < bp_slots_available" is already
> true, isn't it?

yes, en25qh16 is covered. BP3 for EON is what the other manufacturers refer to 
TB.

> But good catch for the en25qh256. IMHO the rework of the BP bits should
> already
> add a flag (together with a reference to this flash) so this information

Is en25qh256 the only flash that breaks the rule? EON did the locking wrong 
for this flash. BP bits are pretty useless in this example because they can 
either protect the upper/lower 32 sectors, or the entire flash. They have a 
bad locking granularity.

I don't like that the info->flags is growing.

If we consider that what EON did was an error, we can introduce a 
post_info_init hook, where we can set a SPI_NOR_BP_SECTOR_LOCK flag into a 
nor->params.locking_ops->flags.

Either way, the introduction of such flag should be done in a separate patch. 
The eon entries do not advertise lock support, we can deal with them with a 
patch on top of the generic bp lock support. A dedicated patch will be smaller 
and easier for readers to grasp.

> is not lost. what about sth like MIN_LOCK_SIZE_IS_ONE_SECTOR.
 
Yes, we should fix/add support for this. How about SPI_NOR_BP_SECTOR_LOCK?

Jungseung, are there any other caveats that you found? Would you work towards 
implementing this generic bp lock proposal? 

Great discussion guys. Cheers,
ta


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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Tudor.Ambarus]

On Friday, February 21, 2020 11:30:22 AM EET Tudor.Ambarus@microchip.com 
wrote:
> Jungseung, are there any other caveats that you found? Would you work
> towards implementing this generic bp lock proposal?

Hi, Jungseung,

It would be great if we can have the BP series included on this release. Let 
us know when/if you plan to work on this proposal or if you need help. No 
pressure, don't get me wrong, I just want to schedule the biggest features.

Cheers,
ta


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Re: [PATCH v3 2/3] mtd: spi-nor: add 4bit block protection support

[Jungseung Lee]

Hi, Tudor 

2020-02-25 (화), 08:20 +0000, Tudor.Ambarus@microchip.com:
> On Friday, February 21, 2020 11:30:22 AM EET 
> Tudor.Ambarus@microchip.com 
> wrote:
> > Jungseung, are there any other caveats that you found? Would you
> > work
> > towards implementing this generic bp lock proposal?
> 
> Hi, Jungseung,
> 
> It would be great if we can have the BP series included on this
> release. Let 
> us know when/if you plan to work on this proposal or if you need
> help. No 
> pressure, don't get me wrong, I just want to schedule the biggest
> features.
> 

Sorry for late response, I was a little busy these days.
I don't feel under pressure. :) I'm honored to have the chance to do
something for the feature.

I think it could be done in a week. (You and michael already wrote a
lot of part of it.)

Thanks,

> Cheers,
> ta
> 
> 


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[PATCH v3 3/3] mtd: spi-nor: support lock/unlock for a few Micron chips

[Jungseung Lee]

Some Micron models are known to have lock/unlock support,
and that also support 4bit block protection (bp0-3).

This patch support lock/unlock feature on the flashes.

Tested on w25q512ax3. The Other is modified following the datasheet.

Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 7e8af6c4fdfa..97a027c38d66 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -2583,12 +2583,17 @@ static const struct flash_info spi_nor_ids[] = {
 	{ "mt25ql512a",  INFO6(0x20ba20, 0x104400, 64 * 1024, 1024,
 			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
 			       SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
-	{ "n25q512ax3",  INFO(0x20ba20, 0, 64 * 1024, 1024, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ) },
+	{ "n25q512ax3",  INFO(0x20ba20, 0, 64 * 1024, 1024,
+			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
+			       SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB |
+			       SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6) },
 	{ "mt25qu512a",  INFO6(0x20bb20, 0x104400, 64 * 1024, 1024,
 			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
 			       SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
-	{ "n25q512a",    INFO(0x20bb20, 0, 64 * 1024, 1024, SECT_4K |
-			      USE_FSR | SPI_NOR_QUAD_READ) },
+	{ "n25q512a",    INFO(0x20bb20, 0, 64 * 1024, 1024,
+			       SECT_4K | USE_FSR | SPI_NOR_QUAD_READ |
+			       SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB |
+			       SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6) },
 	{ "n25q00",      INFO(0x20ba21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
 	{ "n25q00a",     INFO(0x20bb21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
 	{ "mt25ql02g",   INFO(0x20ba22, 0, 64 * 1024, 4096,
-- 
2.17.1


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Re: [PATCH v3 3/3] mtd: spi-nor: support lock/unlock for a few Micron chips

[John Garry]

On 13/01/2020 05:59, Jungseung Lee wrote:
> Some Micron models are known to have lock/unlock support,
> and that also support 4bit block protection (bp0-3).
> 
> This patch support lock/unlock feature on the flashes.
> 
> Tested on w25q512ax3. The Other is modified following the datasheet.
> 
> Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> ---
>   drivers/mtd/spi-nor/spi-nor.c | 11 ++++++++---
>   1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index 7e8af6c4fdfa..97a027c38d66 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -2583,12 +2583,17 @@ static const struct flash_info spi_nor_ids[] = {
>   	{ "mt25ql512a",  INFO6(0x20ba20, 0x104400, 64 * 1024, 1024,
>   			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
>   			       SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
> -	{ "n25q512ax3",  INFO(0x20ba20, 0, 64 * 1024, 1024, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ) },
> +	{ "n25q512ax3",  INFO(0x20ba20, 0, 64 * 1024, 1024,
> +			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
> +			       SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB |
> +			       SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6) },
>   	{ "mt25qu512a",  INFO6(0x20bb20, 0x104400, 64 * 1024, 1024,
>   			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
>   			       SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
> -	{ "n25q512a",    INFO(0x20bb20, 0, 64 * 1024, 1024, SECT_4K |
> -			      USE_FSR | SPI_NOR_QUAD_READ) },
> +	{ "n25q512a",    INFO(0x20bb20, 0, 64 * 1024, 1024,
> +			       SECT_4K | USE_FSR | SPI_NOR_QUAD_READ |
> +			       SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB |
> +			       SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6) },
>   	{ "n25q00",      INFO(0x20ba21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
>   	{ "n25q00a",     INFO(0x20bb21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
>   	{ "mt25ql02g",   INFO(0x20ba22, 0, 64 * 1024, 4096,
> 

Hi,

I'd like to test on a n25q128a11.

Seems I just need to add "SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB | 		 
SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6" to
n25q128a11 INFO also, right?

Thanks,
John


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Re: [PATCH v3 3/3] mtd: spi-nor: support lock/unlock for a few Micron chips

[Jungseung Lee]

Hi, John

2020-01-13 (Mon), 12:30 +0000, John Garry:
> On 13/01/2020 05:59, Jungseung Lee wrote:
> > Some Micron models are known to have lock/unlock support,
> > and that also support 4bit block protection (bp0-3).
> > 
> > This patch support lock/unlock feature on the flashes.
> > 
> > Tested on w25q512ax3. The Other is modified following the
> > datasheet.
> > 
> > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> > ---
> >   drivers/mtd/spi-nor/spi-nor.c | 11 ++++++++---
> >   1 file changed, 8 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-
> > nor/spi-nor.c
> > index 7e8af6c4fdfa..97a027c38d66 100644
> > --- a/drivers/mtd/spi-nor/spi-nor.c
> > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > @@ -2583,12 +2583,17 @@ static const struct flash_info
> > spi_nor_ids[] = {
> >   	{ "mt25ql512a",  INFO6(0x20ba20, 0x104400, 64 * 1024, 1024,
> >   			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
> >   			       SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES)
> > },
> > -	{ "n25q512ax3",  INFO(0x20ba20, 0, 64 * 1024, 1024, SECT_4K |
> > USE_FSR | SPI_NOR_QUAD_READ) },
> > +	{ "n25q512ax3",  INFO(0x20ba20, 0, 64 * 1024, 1024,
> > +			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
> > +			       SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB |
> > +			       SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6)
> > },
> >   	{ "mt25qu512a",  INFO6(0x20bb20, 0x104400, 64 * 1024, 1024,
> >   			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
> >   			       SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES)
> > },
> > -	{ "n25q512a",    INFO(0x20bb20, 0, 64 * 1024, 1024, SECT_4K |
> > -			      USE_FSR | SPI_NOR_QUAD_READ) },
> > +	{ "n25q512a",    INFO(0x20bb20, 0, 64 * 1024, 1024,
> > +			       SECT_4K | USE_FSR | SPI_NOR_QUAD_READ |
> > +			       SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB |
> > +			       SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6)
> > },
> >   	{ "n25q00",      INFO(0x20ba21, 0, 64 * 1024, 2048, SECT_4K |
> > USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
> >   	{ "n25q00a",     INFO(0x20bb21, 0, 64 * 1024, 2048, SECT_4K |
> > USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
> >   	{ "mt25ql02g",   INFO(0x20ba22, 0, 64 * 1024, 4096,
> > 
> 
> Hi,
> 
> I'd like to test on a n25q128a11.
> 
Thanks for your interest.

> Seems I just need to add "SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB | 
> 	 
> SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6" to
> n25q128a11 INFO also, right?
> 
You are right.

> Thanks,
> John
> 
> 
Best Regards,
Jungseung Lee


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Re: [PATCH v3 3/3] mtd: spi-nor: support lock/unlock for a few Micron chips

[Jungseung Lee]

Hi, John

2020-01-13 (Mon), 12:30 +0000, John Garry:
> On 13/01/2020 05:59, Jungseung Lee wrote:
> > Some Micron models are known to have lock/unlock support,
> > and that also support 4bit block protection (bp0-3).
> > 
> > This patch support lock/unlock feature on the flashes.
> > 
> > Tested on w25q512ax3. The Other is modified following the
> > datasheet.
> > 
> > Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> > ---
> >   drivers/mtd/spi-nor/spi-nor.c | 11 ++++++++---
> >   1 file changed, 8 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-
> > nor/spi-nor.c
> > index 7e8af6c4fdfa..97a027c38d66 100644
> > --- a/drivers/mtd/spi-nor/spi-nor.c
> > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > @@ -2583,12 +2583,17 @@ static const struct flash_info
> > spi_nor_ids[] = {
> >   	{ "mt25ql512a",  INFO6(0x20ba20, 0x104400, 64 * 1024, 1024,
> >   			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
> >   			       SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES)
> > },
> > -	{ "n25q512ax3",  INFO(0x20ba20, 0, 64 * 1024, 1024, SECT_4K |
> > USE_FSR | SPI_NOR_QUAD_READ) },
> > +	{ "n25q512ax3",  INFO(0x20ba20, 0, 64 * 1024, 1024,
> > +			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
> > +			       SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB |
> > +			       SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6)
> > },
> >   	{ "mt25qu512a",  INFO6(0x20bb20, 0x104400, 64 * 1024, 1024,
> >   			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
> >   			       SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES)
> > },
> > -	{ "n25q512a",    INFO(0x20bb20, 0, 64 * 1024, 1024, SECT_4K |
> > -			      USE_FSR | SPI_NOR_QUAD_READ) },
> > +	{ "n25q512a",    INFO(0x20bb20, 0, 64 * 1024, 1024,
> > +			       SECT_4K | USE_FSR | SPI_NOR_QUAD_READ |
> > +			       SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB |
> > +			       SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6)
> > },
> >   	{ "n25q00",      INFO(0x20ba21, 0, 64 * 1024, 2048, SECT_4K |
> > USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
> >   	{ "n25q00a",     INFO(0x20bb21, 0, 64 * 1024, 2048, SECT_4K |
> > USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
> >   	{ "mt25ql02g",   INFO(0x20ba22, 0, 64 * 1024, 4096,
> > 
> 
> Hi,
> 
> I'd like to test on a n25q128a11.
> 
Thanks for your interest to my patches.

> Seems I just need to add "SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB | 
> 	 
> SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6" to
> n25q128a11 INFO also, right?
You're right.

> Thanks,
> John
> 
> 
Best Regards,
Jungseung Lee


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Re: [PATCH v3 3/3] mtd: spi-nor: support lock/unlock for a few Micron chips

[John Garry]

On 13/01/2020 12:45, Jungseung Lee wrote:
> Hi, John
> 
> 2020-01-13 (Mon), 12:30 +0000, John Garry:
>> On 13/01/2020 05:59, Jungseung Lee wrote:
>>> Some Micron models are known to have lock/unlock support,
>>> and that also support 4bit block protection (bp0-3).
>>>
>>> This patch support lock/unlock feature on the flashes.
>>>
>>> Tested on w25q512ax3. The Other is modified following the
>>> datasheet.
>>>
>>> Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
>>> ---
>>>    drivers/mtd/spi-nor/spi-nor.c | 11 ++++++++---
>>>    1 file changed, 8 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-
>>> nor/spi-nor.c
>>> index 7e8af6c4fdfa..97a027c38d66 100644
>>> --- a/drivers/mtd/spi-nor/spi-nor.c
>>> +++ b/drivers/mtd/spi-nor/spi-nor.c
>>> @@ -2583,12 +2583,17 @@ static const struct flash_info
>>> spi_nor_ids[] = {
>>>    	{ "mt25ql512a",  INFO6(0x20ba20, 0x104400, 64 * 1024, 1024,
>>>    			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
>>>    			       SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES)
>>> },
>>> -	{ "n25q512ax3",  INFO(0x20ba20, 0, 64 * 1024, 1024, SECT_4K |
>>> USE_FSR | SPI_NOR_QUAD_READ) },
>>> +	{ "n25q512ax3",  INFO(0x20ba20, 0, 64 * 1024, 1024,
>>> +			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
>>> +			       SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB |
>>> +			       SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6)
>>> },
>>>    	{ "mt25qu512a",  INFO6(0x20bb20, 0x104400, 64 * 1024, 1024,
>>>    			       SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
>>>    			       SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES)
>>> },
>>> -	{ "n25q512a",    INFO(0x20bb20, 0, 64 * 1024, 1024, SECT_4K |
>>> -			      USE_FSR | SPI_NOR_QUAD_READ) },
>>> +	{ "n25q512a",    INFO(0x20bb20, 0, 64 * 1024, 1024,
>>> +			       SECT_4K | USE_FSR | SPI_NOR_QUAD_READ |
>>> +			       SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB |
>>> +			       SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6)
>>> },
>>>    	{ "n25q00",      INFO(0x20ba21, 0, 64 * 1024, 2048, SECT_4K |
>>> USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
>>>    	{ "n25q00a",     INFO(0x20bb21, 0, 64 * 1024, 2048, SECT_4K |
>>> USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
>>>    	{ "mt25ql02g",   INFO(0x20ba22, 0, 64 * 1024, 4096,
>>>
>>
>> Hi,
>>
>> I'd like to test on a n25q128a11.
>>
> Thanks for your interest to my patches.
> 
>> Seems I just need to add "SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB |
>> 	
>> SPI_NOR_HAS_BP3 | SPI_NOR_BP3_SR_BIT6" to
>> n25q128a11 INFO also, right?
> You're right.
> 
>> Thanks,
>> John
>>
>>
> Best Regards,
> Jungseung Lee

OK, great. So from *limited* testing (which you can judge by my response 
time), this seems to work ok:

root@ubuntu:/home/john# sudo flash_lock -l /dev/mtd0
root@ubuntu:/home/john# sudo mtd_debug write /dev/mtd0 0x100000 4096 
dump4096
[  220.310538] spi-nor spi-PRP0001:00: Program operation failed.
[  220.316314] spi-nor spi-PRP0001:00: Attempted to modify a protected 
sector.
file_to_flash: write, size 0x1000, n 0x1000
write(): Input/output error
root@ubuntu:/home/john# sudo flash_lock -u /dev/mtd0
flash_lock: error!: could not unlock device: /dev/mtd0

             error 5 (Input/output error)
root@ubuntu:/home/john# sudo flash_lock -u /dev/mtd0
root@ubuntu:/home/john# sudo mtd_debug write /dev/mtd0 0x100000 4096 
dump4096
Copied 4096 bytes from dump4096 to address 0x00100000 in flash
root@ubuntu:/home/john#

This write to the bottom portion was previously passing (which was 
improper to do so). Note that the flash_lock -u error is a known issue.

I'll test further this/next week if I get a chance.

Thanks,
John



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Re: [PATCH v3 1/3] mtd: spi-nor: introduce SR_BP_SHIFT define

[Tudor.Ambarus]

On Monday, January 13, 2020 7:59:05 AM EET Jungseung Lee wrote:
> The shift variable of SR_BP is conclusive because the first bit of SR_BP
> is fixed on all known flashes.
> 
> Introduce SR_BP_SHIFT define and let them used by stm_* functions
> to replace ffs operation to get shift value.
> 
> Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
> ---
>  drivers/mtd/spi-nor/spi-nor.c | 11 +++++------
>  include/linux/mtd/spi-nor.h   |  2 ++
>  2 files changed, 7 insertions(+), 6 deletions(-)

Applied to spi-nor/next. Thanks.

ta


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