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

Jungseung Lee
2020-01-10T10:23:38Z

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>
---
drivers/mtd/spi-nor/spi-nor.c | 90 +++++++++++++++++++++++++++++++----
include/linux/mtd/spi-nor.h | 8 ++++
2 files changed, 88 insertions(+), 10 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index e3da6a8654a8..214f3b733e9b 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;
@@ -1766,24 +1774,48 @@ 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 tb_mask = SR_TB_BIT5, bp;
+ int pow = 0;

if (nor->flags & SNOR_F_HAS_SR_TB_BIT6)
tb_mask = SR_TB_BIT6;

- if (!(sr & mask)) {
+ 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;
+ } else {
+ bp = (sr & mask) >> SR_BP_SHIFT;
+ }
+
+ if (!bp) {
/* No protection */
*ofs = 0;
*len = 0;
+ return;
+ }
+
+ if (nor->flags & SNOR_F_HAS_SR_BP3) {
+ 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)
- *ofs = 0;
- else
- *ofs = mtd->size - *len;
+ 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;
}

/*
@@ -1898,6 +1930,12 @@ 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 +1946,17 @@ 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 +2031,13 @@ 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:
*
@@ -1995,6 +2050,14 @@ 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) - pow + 1;
+ val = val << SR_BP_SHIFT;
+
+ if (val & BIT(5) && mask & SR_BP3_BIT6)
+ val = (val & ~BIT(5)) | BIT(6);
+ if (val & ~mask)
+ return -EINVAL;
} else {
val = mask - (pow << SR_BP_SHIFT);
/* Some power-of-two sizes are not supported */
@@ -4736,6 +4799,7 @@ 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 +5256,11 @@ 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 +5268,7 @@ 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