Re: [PATCH 1/4] mtd: spi-nor: macronix: add support for Macronix octaflash

Pratyush Yadav
2021-08-13T18:06:47Z

On 13/08/21 03:25PM, JaimeLiao wrote:
> Follow patch "f6adec1af4b2f5d3012480c6cdce7743b74a6156" for adding
> Macronix flash in Octal DTR mode.
> Enable Octal DTR mode with 20 dummy cycles to allow running at the
> maximum supported frequency.

Please include a link to the flash datasheet so the reviewers can
properly review your patch.

>
> Signed-off-by: JaimeLiao <jaimeliao.tw@gmail.com>
> ---
> drivers/mtd/spi/spi-nor-core.c | 75 ++++++++++++++++++++++++++++++++++
> include/linux/mtd/spi-nor.h | 13 +++++-
> 2 files changed, 86 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
> index d5d905fa5a..6b195b1fd3 100644
> --- a/drivers/mtd/spi/spi-nor-core.c
> +++ b/drivers/mtd/spi/spi-nor-core.c
> @@ -3489,6 +3489,77 @@ static struct spi_nor_fixups mt35xu512aba_fixups = {
> };
> #endif /* CONFIG_SPI_FLASH_MT35XU */
>
> +#ifdef CONFIG_SPI_FLASH_MACRONIX
> +/**
> + * spi_nor_macronix_octal_dtr_enable() - set DTR OPI Enable bit in Configuration Register 2.
> + * @nor: pointer to a 'struct spi_nor'
> + *
> + * Set the DTR OPI Enable (DOPI) bit in Configuration Register 2.

Nitpick: Why the blank line here?
> + *
> + * bit 2 of Configuration Register 2 is the DOPI bit for Macronix like OPI memories.

Nitpick: Capitalize the 'b'.

> + *
> + * Return: 0 on success, -errno otherwise.
> + */
> +static int spi_nor_macronix_octal_dtr_enable(struct spi_nor *nor)
> +{
> + struct spi_mem_op op;
> + int ret;
> + u8 buf;
> +
> + write_enable(nor);

Need to check the return code here.

> +
> + buf = SPINOR_REG_MXIC_DC_20;
> + op = (struct spi_mem_op)
> + SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_CR2, 1),
> + SPI_MEM_OP_ADDR(4, SPINOR_REG_MXIC_CR2_DC, 1),
> + SPI_MEM_OP_NO_DUMMY,
> + SPI_MEM_OP_DATA_OUT(1, &buf, 1));
> +
> + ret = spi_mem_exec_op(nor->spi, &op);
> + if (ret)
> + return ret;
> +
> + ret = spi_nor_wait_till_ready(nor);
> + if (ret)
> + return ret;
> +
> + nor->read_dummy = MXIC_MAX_DC;
> + write_enable(nor);
> +
> + buf = SPINOR_REG_MXIC_OPI_DTR_EN;
> + op = (struct spi_mem_op)
> + SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_CR2, 1),
> + SPI_MEM_OP_ADDR(4, SPINOR_REG_MXIC_CR2_MODE, 1),
> + SPI_MEM_OP_NO_DUMMY,
> + SPI_MEM_OP_DATA_OUT(1, &buf, 1));
> +
> + ret = spi_mem_exec_op(nor->spi, &op);
> + if (ret) {
> + dev_err(nor->dev, "Failed to enable octal DTR mode\n");
> + return ret;
> + }
> + nor->reg_proto = SNOR_PROTO_8_8_8_DTR;
> +
> + return 0;
> +}
> +
> +static void macronix_default_init(struct spi_nor *nor)
> +{
> + nor->octal_dtr_enable = spi_nor_macronix_octal_dtr_enable;
> +}
> +
> +static void macronix_post_sfdp_fixup(struct spi_nor *nor,
> + struct spi_nor_flash_parameter *params)
> +{
> + params->hwcaps.mask |= SNOR_HWCAPS_PP_8_8_8_DTR;

This does not seem right. You would mark every Macronix flash Octal DTR
capable which is clearly not true.

> +}
> +
> +static struct spi_nor_fixups macronix_fixups = {
> + .default_init = macronix_default_init,
> + .post_sfdp = macronix_post_sfdp_fixup,
> +};
> +#endif /* CONFIG_SPI_FLASH_MACRONIX */
> +
> /** spi_nor_octal_dtr_enable() - enable Octal DTR I/O if needed
> * @nor: pointer to a 'struct spi_nor'
> *
> @@ -3655,6 +3726,10 @@ void spi_nor_set_fixups(struct spi_nor *nor)
> if (!strcmp(nor->info->name, "mt35xu512aba"))
> nor->fixups = &mt35xu512aba_fixups;
> #endif
> +
> +#ifdef CONFIG_SPI_FLASH_MACRONIX
> + nor->fixups = &macronix_fixups;
> +#endif
> }
>
> int spi_nor_scan(struct spi_nor *nor)
> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> index 7ddc4ba2bf..2ad579f66d 100644
> --- a/include/linux/mtd/spi-nor.h
> +++ b/include/linux/mtd/spi-nor.h
> @@ -116,8 +116,17 @@
> #define XSR_RDY BIT(7) /* Ready */
>
> /* Used for Macronix and Winbond flashes. */
> -#define SPINOR_OP_EN4B 0xb7 /* Enter 4-byte mode */
> -#define SPINOR_OP_EX4B 0xe9 /* Exit 4-byte mode */
> +#define SPINOR_OP_EN4B 0xb7 /* Enter 4-byte mode */
> +#define SPINOR_OP_EX4B 0xe9 /* Exit 4-byte mode */
> +#define SPINOR_OP_RD_CR2 0x71 /* Read configuration register 2 */
> +#define SPINOR_OP_WR_CR2 0x72 /* Write configuration register 2 */
> +#define SPINOR_OP_MXIC_DTR_RD 0xee /* Fast Read opcode in DTR mode */
> +#define SPINOR_REG_MXIC_CR2_MODE 0x00000000 /* For setting octal DTR mode */
> +#define SPINOR_REG_MXIC_OPI_DTR_EN 0x2 /* Enable Octal DTR */
> +#define SPINOR_REG_MXIC_OPI_DTR_DIS 0x1 /* Disable Octal DTR */
> +#define SPINOR_REG_MXIC_CR2_DC 0x00000300 /* For setting dummy cycles */
> +#define SPINOR_REG_MXIC_DC_20 0x0 /* Setting dummy cycles to 20 */
> +#define MXIC_MAX_DC 20 /* Maximum value of dummy cycles */
>
> /* Used for Spansion flashes only. */
> #define SPINOR_OP_BRWR 0x17 /* Bank register write */
> --
> 2.17.1
>

--
Regards,
Pratyush Yadav
Texas Instruments Inc.