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SubjectRe: [PATCH 19/23] mtd: spi-nor: Rework spansion(_no)_read_cr_quad_enable()
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On 09/19/2019 08:34 PM, Vignesh Raghavendra wrote:
>
>
> On 17-Sep-19 9:25 PM, Tudor.Ambarus@microchip.com wrote:
>> From: Tudor Ambarus <tudor.ambarus@microchip.com>
>>
>> Merge:
>> spansion_no_read_cr_quad_enable()
>> spansion_read_cr_quad_enable()
>>
>> in spi_nor_sr2_bit1_quad_enable().
>>
>> Avoid duplication of code by using spi_nor_write_16bit_sr_and_check(),
>> the SNOR_F_NO_READ_CR case is treated there.
>>
>> We now do the Read Back test even for the old
>> spansion_no_read_cr_quad_enable() case.
>>
>> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
>> ---
>> drivers/mtd/spi-nor/spi-nor.c | 89 ++++++++++---------------------------------
>> include/linux/mtd/spi-nor.h | 4 +-
>> 2 files changed, 22 insertions(+), 71 deletions(-)
>>
>> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
>> index 2f79923e7db5..8648666fb9bd 100644
>> --- a/drivers/mtd/spi-nor/spi-nor.c
>> +++ b/drivers/mtd/spi-nor/spi-nor.c
>> @@ -907,7 +907,7 @@ static int spi_nor_write_16bit_sr_and_check(struct spi_nor *nor, u8 status_new,
>> * Write Status (01h) command is available just for the cases
>> * in which the QE bit is described in SR2 at BIT(1).
>> */
>> - sr_cr[1] = CR_QUAD_EN_SPAN;
>> + sr_cr[1] = SR2_QUAD_EN_BIT1;
>> } else {
>> sr_cr[1] = 0;
>> }
>> @@ -1963,81 +1963,34 @@ static int spi_nor_sr1_bit6_quad_enable(struct spi_nor *nor)
>> }
>>
>> /**
>> - * spansion_no_read_cr_quad_enable() - set QE bit in Configuration Register.
>> + * spi_nor_sr2_bit1_quad_enable() - set the Quad Enable BIT(1) in the Status
>> + * Register 2.
>> * @nor: pointer to a 'struct spi_nor'
>> *
>> - * Set the Quad Enable (QE) bit in the Configuration Register.
>> - * This function should be used with QSPI memories not supporting the Read
>> - * Configuration Register (35h) instruction.
>> - *
>> - * bit 1 of the Configuration Register is the QE bit for Spansion like QSPI
>> - * memories.
>> - *
>> - * Return: 0 on success, -errno otherwise.
>> - */
>> -static int spansion_no_read_cr_quad_enable(struct spi_nor *nor)
>> -{
>> - u8 *sr_cr = nor->bouncebuf;
>> - int ret;
>> -
>> - /* Keep the current value of the Status Register. */
>> - ret = spi_nor_read_sr(nor, &sr_cr[0]);
>> - if (ret)
>> - return ret;
>> -
>> - sr_cr[1] = CR_QUAD_EN_SPAN;
>> -
>> - return spi_nor_write_sr(nor, sr_cr, 2);
>> -}
>> -
>> -/**
>> - * spansion_read_cr_quad_enable() - set QE bit in Configuration Register.
>> - * @nor: pointer to a 'struct spi_nor'
>> - *
>> - * Set the Quad Enable (QE) bit in the Configuration Register.
>> - * This function should be used with QSPI memories supporting the Read
>> - * Configuration Register (35h) instruction.
>> - *
>> - * bit 1 of the Configuration Register is the QE bit for Spansion like QSPI
>> - * memories.
>> + * Bit 1 of the Status Register 2 is the QE bit for Spansion like QSPI memories.
>> *
>> * Return: 0 on success, -errno otherwise.
>> */
>> -static int spansion_read_cr_quad_enable(struct spi_nor *nor)
>> +static int spi_nor_sr2_bit1_quad_enable(struct spi_nor *nor)
>> {
>> - u8 *sr_cr = nor->bouncebuf;
>> int ret;
>>
>> - /* Check current Quad Enable bit value. */
>> - ret = spi_nor_read_cr(nor, &sr_cr[1]);
>> - if (ret)
>> - return ret;
>> -
>> - if (sr_cr[1] & CR_QUAD_EN_SPAN)
>> - return 0;
>> + if (!(nor->flags & SNOR_F_NO_READ_CR)) {
>> + /* Check current Quad Enable bit value. */
>> + ret = spi_nor_read_cr(nor, &nor->bouncebuf[0]);
>> + if (ret)
>> + return ret;
>>
>> - sr_cr[1] |= CR_QUAD_EN_SPAN;
>> + if (nor->bouncebuf[0] & SR2_QUAD_EN_BIT1)
>> + return 0;
>> + }
>>
>> /* Keep the current value of the Status Register. */
>> - ret = spi_nor_read_sr(nor, &sr_cr[0]);
>> - if (ret)
>> - return ret;
>> -
>> - ret = spi_nor_write_sr(nor, sr_cr, 2);
>> - if (ret)
>> - return ret;
>> -
>> - /* Read back and check it. */
>> - ret = spi_nor_read_cr(nor, &sr_cr[1]);
>> + ret = spi_nor_read_sr(nor, &nor->bouncebuf[0]);
>> if (ret)
>> return ret;
>>
>> - if (!(sr_cr[1] & CR_QUAD_EN_SPAN)) {
>> - dev_err(nor->dev, "Spansion Quad bit not set\n");
>> - return -EIO;
>> - }
>> -
>> - return 0;
>
> You need to set QE bit here before writing to CR register. This function
> does not do that.>
>> + return spi_nor_write_16bit_sr_and_check(nor, nor->bouncebuf[0], 0xFF);>
> Neither does spi_nor_write_16bit_sr_and_check().

pff, you're right, I thought I did set it in spi_nor_write_16bit_sr_and_check(),
but in spi_nor_write_16bit_sr_and_check() I just read the CR, without setting
the QE bit. Will respin the entire series, thanks for catching this!

> We need a function that allows to modify SR2/CR register content as well
> so as to set QE bit right?
>
> Regards
> Vignesh
>
>> }
>>
>> /**
>> @@ -2117,7 +2070,7 @@ static int spi_nor_clear_sr_bp(struct spi_nor *nor)
>> *
>> * Read-modify-write function that clears the Block Protection bits from the
>> * Status Register without affecting other bits. The function is tightly
>> - * coupled with the spansion_read_cr_quad_enable() function. Both assume that
>> + * coupled with the spi_nor_sr2_bit1_quad_enable() function. Both assume that
>> * the Write Register with 16 bits, together with the Read Configuration
>> * Register (35h) instructions are supported.
>> *
>> @@ -2138,7 +2091,7 @@ static int spi_nor_spansion_clear_sr_bp(struct spi_nor *nor)
>> * When the configuration register Quad Enable bit is one, only the
>> * Write Status (01h) command with two data bytes may be used.
>> */
>> - if (sr_cr[1] & CR_QUAD_EN_SPAN) {
>> + if (sr_cr[1] & SR2_QUAD_EN_BIT1) {
>> ret = spi_nor_read_sr(nor, &sr_cr[0]);
>> if (ret)
>> return ret;
>> @@ -3642,7 +3595,7 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
>> * supported.
>> */
>> nor->flags |= SNOR_F_NO_READ_CR;
>> - flash->quad_enable = spansion_no_read_cr_quad_enable;
>> + flash->quad_enable = spi_nor_sr2_bit1_quad_enable;
>> break;
>>
>> case BFPT_DWORD15_QER_SR1_BIT6:
>> @@ -3663,7 +3616,7 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
>> * assumption of a 16-bit Write Status (01h) command.
>> */
>> nor->flags |= SNOR_F_HAS_16BIT_SR;
>> - flash->quad_enable = spansion_read_cr_quad_enable;
>> + flash->quad_enable = spi_nor_sr2_bit1_quad_enable;
>> break;
>>
>> default:
>> @@ -4626,7 +4579,7 @@ static void spi_nor_info_init_flash_params(struct spi_nor *nor)
>> u8 i, erase_mask;
>>
>> /* Initialize legacy flash parameters and settings. */
>> - flash->quad_enable = spansion_read_cr_quad_enable;
>> + flash->quad_enable = spi_nor_sr2_bit1_quad_enable;
>> flash->set_4byte = spansion_set_4byte;
>> flash->setup = spi_nor_default_setup;
>> /* Default to 16-bit Write Status (01h) Command */
>> @@ -4844,7 +4797,7 @@ static int spi_nor_init(struct spi_nor *nor)
>> int err;
>>
>> if (nor->clear_sr_bp) {
>> - if (nor->flash.quad_enable == spansion_read_cr_quad_enable)
>> + if (nor->flash.quad_enable == spi_nor_sr2_bit1_quad_enable)
>> nor->clear_sr_bp = spi_nor_spansion_clear_sr_bp;
>>
>> err = nor->clear_sr_bp(nor);
>> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
>> index 3a835de90b6a..5590a36eb43e 100644
>> --- a/include/linux/mtd/spi-nor.h
>> +++ b/include/linux/mtd/spi-nor.h
>> @@ -144,10 +144,8 @@
>> #define FSR_P_ERR BIT(4) /* Program operation status */
>> #define FSR_PT_ERR BIT(1) /* Protection error bit */
>>
>> -/* Configuration Register bits. */
>> -#define CR_QUAD_EN_SPAN BIT(1) /* Spansion Quad I/O */
>> -
>> /* Status Register 2 bits. */
>> +#define SR2_QUAD_EN_BIT1 BIT(1)
>> #define SR2_QUAD_EN_BIT7 BIT(7)
>>
>> /* Supported SPI protocols */
>>
>
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