[PATCH 4/4] mtd: spi-nor: add generic flash driver

[Tudor Ambarus]

On 08.08.2024 09:00, tkuw584924 at gmail.com wrote:
> From: Takahiro Kuwano <Takahiro.Kuwano at infineon.com>
> 
> Our SFDP parsing is everything we need to support all basic operations
> of a flash device. If the flash isn't found in our in-kernel flash
> database, gracefully fall back to a driver described solely by its SFDP
> tables.
> 
> This patch ports the commit in Linux:
> 773bbe104497 ("mtd: spi-nor: add generic flash driver")

This info shall be the first info in the commit message.

> 
> A new flag named SPI_NOR_PARSE_SFDP is defined to perform SFDP parse for
> the spi-nor-generic. And spi_nor_read_id() is moved to later part than
> SFDP functions.
> 
> Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano at infineon.com>
> ---
>  drivers/mtd/spi/sf_internal.h  |  1 +
>  drivers/mtd/spi/spi-nor-core.c | 95 ++++++++++++++++++++++++----------
>  2 files changed, 70 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/mtd/spi/sf_internal.h b/drivers/mtd/spi/sf_internal.h
> index 57608750c9..f7b0cea983 100644
> --- a/drivers/mtd/spi/sf_internal.h
> +++ b/drivers/mtd/spi/sf_internal.h
> @@ -68,6 +68,7 @@ struct flash_info {
>  #define SPI_NOR_HAS_SST26LOCK	BIT(14)	/* Flash supports lock/unlock via BPR */
>  #define SPI_NOR_OCTAL_READ	BIT(15)	/* Flash supports Octal Read */
>  #define SPI_NOR_OCTAL_DTR_READ	BIT(16)	/* Flash supports Octal DTR Read */
> +#define SPI_NOR_PARSE_SFDP	BIT(17)	/* Parse SFDP tables */
>  };
>  
>  extern const struct flash_info spi_nor_ids[];
> diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
> index feafc48a49..c1186271a4 100644
> --- a/drivers/mtd/spi/spi-nor-core.c
> +++ b/drivers/mtd/spi/spi-nor-core.c
> @@ -1509,31 +1509,6 @@ static int stm_is_unlocked(struct spi_nor *nor, loff_t ofs, uint64_t len)
>  #endif /* CONFIG_SPI_FLASH_STMICRO */
>  #endif
>  
> -static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
> -{
> -	int			tmp;
> -	u8			id[SPI_NOR_MAX_ID_LEN];
> -	const struct flash_info	*info;
> -
> -	tmp = nor->read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
> -	if (tmp < 0) {
> -		dev_dbg(nor->dev, "error %d reading JEDEC ID\n", tmp);
> -		return ERR_PTR(tmp);
> -	}
> -
> -	info = spi_nor_ids;
> -	for (; info->name; info++) {
> -		if (info->id_len) {
> -			if (!memcmp(info->id, id, info->id_len))
> -				return info;
> -		}
> -	}
> -
> -	dev_err(nor->dev, "unrecognized JEDEC id bytes: %02x, %02x, %02x\n",
> -		id[0], id[1], id[2]);
> -	return ERR_PTR(-ENODEV);
> -}
> -

the linux commit didn't move code around, so don't do it here. If needed
specify why and do it in a dedicated commit. If you care about not
mixing sfdp code with core code, let's late on introduce sfdp.c.

>  static int spi_nor_read(struct mtd_info *mtd, loff_t from, size_t len,
>  			size_t *retlen, u_char *buf)
>  {
> @@ -2154,6 +2129,17 @@ spi_nor_set_pp_settings(struct spi_nor_pp_command *pp,
>  }
>  
>  #if CONFIG_IS_ENABLED(SPI_FLASH_SFDP_SUPPORT)
> +
> +static const struct flash_info spi_nor_generic_flash = {
> +	.name = "spi-nor-generic",
> +	/*
> +	 * JESD216 rev A doesn't specify the page size, therefore we need a
> +	 * sane default.
> +	 */
> +	.page_size = 256,
> +	.flags = SPI_NOR_PARSE_SFDP,

what was wrong with .parse_sfdp = true ?