Re: [PATCH V10 2/2] mtd: spi-nor: Add driver for Cadence Quad SPI Flash Controller.

Marek Vasut
2016-04-13T15:06:52Z

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On 04/07/2016 06:55 AM, Vignesh R wrote:
>
>
> On 04/07/2016 01:00 AM, Marek Vasut wrote:
>> On 04/06/2016 06:55 PM, R, Vignesh wrote:
>>> Hi Marek,
>>
>> Hi!
>>
>>> I encountered a issue with this driver while testing.
>>
>> Try with the attached patches, I am planning to use them for V11
>> submission. I think you're hitting the problem with missing buslock.
>>
>
> Thanks for the patches.
> But I am pretty sure that's not the problem at my end, because I have
> only one flash device on QSPI bus.
>
> The problem is cqspi_switch_cs() is called only once ie when JEDEC ID is
> being read(during autodetect of chip), but at that instance,
> nor->page_size and nor->mtd.erasesize are not yet initialized (They are
> initialized only after JEDEC ID is looked up in the table and page_size
> and erasesize are known).
> Therefore if nor->page_size is printed during cqspi_switch_cs() then its
> zero. But nor->page_size reports 256 when printed in cqspi_flash_setup()
> after spi_nor_scan(). Therefore CQSPI_REG_SIZE register has to be
> configured only after spi_nor struct is fully populated (i.e after
> spi_nor_scan() has recognized the slave after JEDEC ID read).

Got it and I have a patch for this. Nice find, thanks! It gave me 60%
read performance boost on my machine :-)

I am now caching the page_size, erasesize, addr_width values, so I can
avoid reconfiguring the controller if there is no need for it, but
reconfigure it if there is a need. The patch is attached, but it's quite
big, so I also pushed a git branch with this driver for your convenience
(based on linux-next, expect rebases):

https://git.kernel.org/cgit/linux/kernel/git/marex/linux-2.6.git/log/?h=next/cadence-qspi

--
Best regards,
Marek Vasut

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diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
index 7e61fba..331e7d1 100644
--- a/drivers/mtd/spi-nor/cadence-quadspi.c
+++ b/drivers/mtd/spi-nor/cadence-quadspi.c
@@ -66,6 +66,9 @@ struct cqspi_st {
struct mutex bus_mutex;

int current_cs;
+ int current_page_size;
+ int current_erase_size;
+ int current_addr_width;
unsigned long master_ref_clk_hz;
bool is_decoded_cs;
u32 fifo_depth;
@@ -654,109 +657,60 @@ failwr:
return ret;
}

-static int cqspi_set_protocol(struct spi_nor *nor, enum spi_nor_protocol proto)
+static void cqspi_chipselect(struct spi_nor *nor)
{
struct cqspi_flash_pdata *f_pdata = nor->priv;
+ struct cqspi_st *cqspi = f_pdata->cqspi;
+ void __iomem *reg_base = cqspi->iobase;
+ unsigned int chip_select = f_pdata->cs;
+ unsigned int reg;

- switch (proto) {
- case SNOR_PROTO_1_1_1:
- case SNOR_PROTO_1_1_2:
- case SNOR_PROTO_1_1_4:
- case SNOR_PROTO_1_2_2:
- case SNOR_PROTO_1_4_4:
- f_pdata->inst_width = CQSPI_INST_TYPE_SINGLE;
- break;
- case SNOR_PROTO_2_2_2:
- f_pdata->inst_width = CQSPI_INST_TYPE_DUAL;
- break;
- case SNOR_PROTO_4_4_4:
- f_pdata->inst_width = CQSPI_INST_TYPE_QUAD;
- break;
- default:
- return -EINVAL;
- }
+ reg = readl(reg_base + CQSPI_REG_CONFIG);
+ if (cqspi->is_decoded_cs) {
+ reg |= CQSPI_REG_CONFIG_DECODE_MASK;
+ } else {
+ reg &= ~CQSPI_REG_CONFIG_DECODE_MASK;

- switch (proto) {
- case SNOR_PROTO_1_1_1:
- case SNOR_PROTO_1_1_2:
- case SNOR_PROTO_1_1_4:
- f_pdata->addr_width = CQSPI_INST_TYPE_SINGLE;
- break;
- case SNOR_PROTO_1_2_2:
- case SNOR_PROTO_2_2_2:
- f_pdata->addr_width = CQSPI_INST_TYPE_DUAL;
- break;
- case SNOR_PROTO_1_4_4:
- case SNOR_PROTO_4_4_4:
- f_pdata->addr_width = CQSPI_INST_TYPE_QUAD;
- break;
- default:
- return -EINVAL;
+ /* Convert CS if without decoder.
+ * CS0 to 4b'1110
+ * CS1 to 4b'1101
+ * CS2 to 4b'1011
+ * CS3 to 4b'0111
+ */
+ chip_select = 0xF & ~(1 << chip_select);
}

- return 0;
-}
-
-static void cqspi_write(struct spi_nor *nor, loff_t to,
- size_t len, size_t *retlen, const u_char *buf)
-{
- int ret;
-
- ret = cqspi_set_protocol(nor, nor->write_proto);
- if (ret)
- return;
-
- ret = cqspi_indirect_write_setup(nor, to);
- if (ret)
- return;
-
- ret = cqspi_indirect_write_execute(nor, buf, len);
- if (ret)
- return;
-
- *retlen += len;
-}
-
-static int cqspi_read(struct spi_nor *nor, loff_t from,
- size_t len, size_t *retlen, u_char *buf)
-{
- int ret;
-
- ret = cqspi_set_protocol(nor, nor->read_proto);
- if (ret)
- return ret;
-
- ret = cqspi_indirect_read_setup(nor, from);
- if (ret)
- return ret;
-
- ret = cqspi_indirect_read_execute(nor, buf, len);
- if (ret)
- return ret;
-
- *retlen += len;
- return ret;
+ reg &= ~(CQSPI_REG_CONFIG_CHIPSELECT_MASK
+ << CQSPI_REG_CONFIG_CHIPSELECT_LSB);
+ reg |= (chip_select & CQSPI_REG_CONFIG_CHIPSELECT_MASK)
+ << CQSPI_REG_CONFIG_CHIPSELECT_LSB;
+ writel(reg, reg_base + CQSPI_REG_CONFIG);
}

-static int cqspi_erase(struct spi_nor *nor, loff_t offs)
+static void cqspi_configure_cs_and_sizes(struct spi_nor *nor)
{
- int ret;
-
- ret = cqspi_set_protocol(nor, nor->erase_proto);
- if (ret)
- return ret;
+ struct cqspi_flash_pdata *f_pdata = nor->priv;
+ struct cqspi_st *cqspi = f_pdata->cqspi;
+ void __iomem *iobase = cqspi->iobase;
+ unsigned int reg;

- /* Send write enable, then erase commands. */
- ret = nor->write_reg(nor, SPINOR_OP_WREN, NULL, 0);
- if (ret)
- return ret;
+ /* configure page size and block size. */
+ reg = readl(iobase + CQSPI_REG_SIZE);
+ reg &= ~(CQSPI_REG_SIZE_PAGE_MASK << CQSPI_REG_SIZE_PAGE_LSB);
+ reg &= ~(CQSPI_REG_SIZE_BLOCK_MASK << CQSPI_REG_SIZE_BLOCK_LSB);
+ reg &= ~CQSPI_REG_SIZE_ADDRESS_MASK;
+ reg |= (nor->page_size << CQSPI_REG_SIZE_PAGE_LSB);
+ reg |= (ilog2(nor->mtd.erasesize) << CQSPI_REG_SIZE_BLOCK_LSB);
+ reg |= (nor->addr_width - 1);
+ writel(reg, iobase + CQSPI_REG_SIZE);

- /* Set up command buffer. */
- ret = cqspi_command_write_addr(nor, nor->erase_opcode, offs);
- if (ret)
- return ret;
+ /* configure the chip select */
+ cqspi_chipselect(nor);

- return 0;
+ /* Store the new configuration of the controller */
+ cqspi->current_page_size = nor->page_size;
+ cqspi->current_erase_size = nor->mtd.erasesize;
+ cqspi->current_addr_width = nor->addr_width;
}

static unsigned int calculate_ticks_for_ns(const unsigned int ref_clk_hz,
@@ -854,36 +808,6 @@ static void cqspi_readdata_capture(struct cqspi_st *cqspi,
writel(reg, reg_base + CQSPI_REG_READCAPTURE);
}

-static void cqspi_chipselect(struct spi_nor *nor)
-{
- struct cqspi_flash_pdata *f_pdata = nor->priv;
- struct cqspi_st *cqspi = f_pdata->cqspi;
- void __iomem *reg_base = cqspi->iobase;
- unsigned int chip_select = f_pdata->cs;
- unsigned int reg;
-
- reg = readl(reg_base + CQSPI_REG_CONFIG);
- if (cqspi->is_decoded_cs) {
- reg |= CQSPI_REG_CONFIG_DECODE_MASK;
- } else {
- reg &= ~CQSPI_REG_CONFIG_DECODE_MASK;
-
- /* Convert CS if without decoder.
- * CS0 to 4b'1110
- * CS1 to 4b'1101
- * CS2 to 4b'1011
- * CS3 to 4b'0111
- */
- chip_select = 0xF & ~(1 << chip_select);
- }
-
- reg &= ~(CQSPI_REG_CONFIG_CHIPSELECT_MASK
- << CQSPI_REG_CONFIG_CHIPSELECT_LSB);
- reg |= (chip_select & CQSPI_REG_CONFIG_CHIPSELECT_MASK)
- << CQSPI_REG_CONFIG_CHIPSELECT_LSB;
- writel(reg, reg_base + CQSPI_REG_CONFIG);
-}
-
static void cqspi_controller_enable(struct cqspi_st *cqspi, bool enable)
{
void __iomem *reg_base = cqspi->iobase;
@@ -899,34 +823,18 @@ static void cqspi_controller_enable(struct cqspi_st *cqspi, bool enable)
writel(reg, reg_base + CQSPI_REG_CONFIG);
}

-static void cqspi_switch_cs(struct spi_nor *nor)
-{
- struct cqspi_flash_pdata *f_pdata = nor->priv;
- struct cqspi_st *cqspi = f_pdata->cqspi;
- void __iomem *iobase = cqspi->iobase;
- unsigned int reg;
-
- /* configure page size and block size. */
- reg = readl(iobase + CQSPI_REG_SIZE);
- reg &= ~(CQSPI_REG_SIZE_PAGE_MASK << CQSPI_REG_SIZE_PAGE_LSB);
- reg &= ~(CQSPI_REG_SIZE_BLOCK_MASK << CQSPI_REG_SIZE_BLOCK_LSB);
- reg &= ~CQSPI_REG_SIZE_ADDRESS_MASK;
- reg |= (nor->page_size << CQSPI_REG_SIZE_PAGE_LSB);
- reg |= (ilog2(nor->mtd.erasesize) << CQSPI_REG_SIZE_BLOCK_LSB);
- reg |= (nor->addr_width - 1);
- writel(reg, iobase + CQSPI_REG_SIZE);
-
- /* configure the chip select */
- cqspi_chipselect(nor);
-}
-
-static int cqspi_prep_unlocked(struct spi_nor *nor, enum spi_nor_ops ops)
+static void cqspi_configure(struct spi_nor *nor)
{
struct cqspi_flash_pdata *f_pdata = nor->priv;
struct cqspi_st *cqspi = f_pdata->cqspi;
const unsigned int sclk = f_pdata->clk_rate;
- const int switch_cs = (cqspi->current_cs != f_pdata->cs);
- const int switch_ck = (cqspi->sclk != sclk);
+ int switch_cs = (cqspi->current_cs != f_pdata->cs);
+ int switch_ck = (cqspi->sclk != sclk);
+
+ if ((cqspi->current_page_size != nor->page_size) ||
+ (cqspi->current_erase_size != nor->mtd.erasesize) ||
+ (cqspi->current_addr_width != nor->addr_width))
+ switch_cs = 1;

if (switch_cs || switch_ck)
cqspi_controller_enable(cqspi, 0);
@@ -934,7 +842,7 @@ static int cqspi_prep_unlocked(struct spi_nor *nor, enum spi_nor_ops ops)
/* Switch chip select. */
if (switch_cs) {
cqspi->current_cs = f_pdata->cs;
- cqspi_switch_cs(nor);
+ cqspi_configure_cs_and_sizes(nor);
}

/* Setup baudrate divisor and delays */
@@ -947,6 +855,111 @@ static int cqspi_prep_unlocked(struct spi_nor *nor, enum spi_nor_ops ops)

if (switch_cs || switch_ck)
cqspi_controller_enable(cqspi, 1);
+}
+
+static int cqspi_set_protocol(struct spi_nor *nor, enum spi_nor_protocol proto)
+{
+ struct cqspi_flash_pdata *f_pdata = nor->priv;
+
+ switch (proto) {
+ case SNOR_PROTO_1_1_1:
+ case SNOR_PROTO_1_1_2:
+ case SNOR_PROTO_1_1_4:
+ case SNOR_PROTO_1_2_2:
+ case SNOR_PROTO_1_4_4:
+ f_pdata->inst_width = CQSPI_INST_TYPE_SINGLE;
+ break;
+ case SNOR_PROTO_2_2_2:
+ f_pdata->inst_width = CQSPI_INST_TYPE_DUAL;
+ break;
+ case SNOR_PROTO_4_4_4:
+ f_pdata->inst_width = CQSPI_INST_TYPE_QUAD;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ switch (proto) {
+ case SNOR_PROTO_1_1_1:
+ case SNOR_PROTO_1_1_2:
+ case SNOR_PROTO_1_1_4:
+ f_pdata->addr_width = CQSPI_INST_TYPE_SINGLE;
+ break;
+ case SNOR_PROTO_1_2_2:
+ case SNOR_PROTO_2_2_2:
+ f_pdata->addr_width = CQSPI_INST_TYPE_DUAL;
+ break;
+ case SNOR_PROTO_1_4_4:
+ case SNOR_PROTO_4_4_4:
+ f_pdata->addr_width = CQSPI_INST_TYPE_QUAD;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ cqspi_configure(nor);
+
+ return 0;
+}
+
+static void cqspi_write(struct spi_nor *nor, loff_t to,
+ size_t len, size_t *retlen, const u_char *buf)
+{
+ int ret;
+
+ ret = cqspi_set_protocol(nor, nor->write_proto);
+ if (ret)
+ return;
+
+ ret = cqspi_indirect_write_setup(nor, to);
+ if (ret)
+ return;
+
+ ret = cqspi_indirect_write_execute(nor, buf, len);
+ if (ret)
+ return;
+
+ *retlen += len;
+}
+
+static int cqspi_read(struct spi_nor *nor, loff_t from,
+ size_t len, size_t *retlen, u_char *buf)
+{
+ int ret;
+
+ ret = cqspi_set_protocol(nor, nor->read_proto);
+ if (ret)
+ return ret;
+
+ ret = cqspi_indirect_read_setup(nor, from);
+ if (ret)
+ return ret;
+
+ ret = cqspi_indirect_read_execute(nor, buf, len);
+ if (ret)
+ return ret;
+
+ *retlen += len;
+ return ret;
+}
+
+static int cqspi_erase(struct spi_nor *nor, loff_t offs)
+{
+ int ret;
+
+ ret = cqspi_set_protocol(nor, nor->erase_proto);
+ if (ret)
+ return ret;
+
+ /* Send write enable, then erase commands. */
+ ret = nor->write_reg(nor, SPINOR_OP_WREN, NULL, 0);
+ if (ret)
+ return ret;
+
+ /* Set up command buffer. */
+ ret = cqspi_command_write_addr(nor, nor->erase_opcode, offs);
+ if (ret)
+ return ret;

return 0;
}
@@ -958,7 +971,7 @@ static int cqspi_prep(struct spi_nor *nor, enum spi_nor_ops ops)

mutex_lock(&cqspi->bus_mutex);

- return cqspi_prep_unlocked(nor, ops);
+ return 0;
}

static void cqspi_unprep(struct spi_nor *nor, enum spi_nor_ops ops)
@@ -974,13 +987,9 @@ static int cqspi_read_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
int ret;

ret = cqspi_set_protocol(nor, nor->reg_proto);
- if (ret)
- goto exit;
-
- cqspi_prep_unlocked(nor, SPI_NOR_OPS_READ);
+ if (!ret)
+ ret = cqspi_command_read(nor, &opcode, 1, buf, len);

- ret = cqspi_command_read(nor, &opcode, 1, buf, len);
-exit:
return ret;
}

@@ -989,13 +998,9 @@ static int cqspi_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
int ret;

ret = cqspi_set_protocol(nor, nor->reg_proto);
- if (ret)
- goto exit;
-
- cqspi_prep_unlocked(nor, SPI_NOR_OPS_WRITE);
+ if (!ret)
+ ret = cqspi_command_write(nor, opcode, buf, len);

- ret = cqspi_command_write(nor, opcode, buf, len);
-exit:
return ret;
}