linux-kernel - Re: [PATCH v2 4/7] mtd: spi-nor: Split spi_nor_init

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Sun, 25 Aug 2019 14:03:02 +0200
From:   Boris Brezillon <boris.brezillon@...labora.com>
To:     <Tudor.Ambarus@...rochip.com>
Cc:     <marek.vasut@...il.com>, <vigneshr@...com>,
        <miquel.raynal@...tlin.com>, <richard@....at>,
        <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 4/7] mtd: spi-nor: Split spi_nor_init_params()

On Sat, 24 Aug 2019 12:00:43 +0000
<Tudor.Ambarus@...rochip.com> wrote:

> From: Tudor Ambarus <tudor.ambarus@...rochip.com>
> 
> Add functions to delimit what the chunks of code do:
> 
> static void spi_nor_init_params()
> {
> 	spi_nor_legacy_init_params()
> 	spi_nor_manufacturer_init_params()
> 	spi_nor_sfdp_init_params()
> }
> 
> Add descriptions to all methods.
> 
> spi_nor_init_params() becomes of type void, as all its children
> return void.
> 
> Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
> ---
>  drivers/mtd/spi-nor/spi-nor.c | 83 ++++++++++++++++++++++++++++++++-----------
>  1 file changed, 63 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index c9514dfd7d6d..93424f914159 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -4186,7 +4186,34 @@ static void spi_nor_manufacturer_init_params(struct spi_nor *nor)
>  		nor->info->fixups->default_init(nor);
>  }
>  
> -static int spi_nor_init_params(struct spi_nor *nor)
> +/**
> + * spi_nor_sfdp_init_params() - Initialize the flash's parameters and settings
> + * based on JESD216 SFDP standard.
> + * @nor:	pointer to a 'struct spi-nor'.
> + *
> + * The method has a roll-back mechanism: in case the SFDP parsing fails, the
> + * legacy flash parameters and settings will be restored.
> + */
> +static void spi_nor_sfdp_init_params(struct spi_nor *nor)
> +{
> +	struct spi_nor_flash_parameter sfdp_params;
> +
> +	memcpy(&sfdp_params, &nor->params, sizeof(sfdp_params));
> +
> +	if (spi_nor_parse_sfdp(nor, &sfdp_params)) {
> +		nor->addr_width = 0;
> +		nor->flags &= ~SNOR_F_4B_OPCODES;
> +	} else {
> +		memcpy(&nor->params, &sfdp_params, sizeof(nor->params));
> +	}
> +}
> +
> +/**
> + * spi_nor_legacy_init_params() - Initialize the flash's parameters and settings
> + * based on nor->info data.
> + * @nor:	pointer to a 'struct spi-nor'.
> + */
> +static void spi_nor_legacy_init_params(struct spi_nor *nor)

Nitpick: hm, I'm not a big fan of the 'legacy' term here as I'm not sure
it reflects the reality. I guess this function will stay around, and
even new NORs are not guaranteed to provide SFDP tables. How about
spi_nor_set_default_params() or spi_nor_info_init_params()?

That's just a suggestion, so here is my

Reviewed-by: Boris Brezillon <boris.brezillon@...labora.com>

in case you want to ignore it.

>  {
>  	struct spi_nor_flash_parameter *params = &nor->params;
>  	struct spi_nor_erase_map *map = &params->erase_map;
> @@ -4260,25 +4287,43 @@ static int spi_nor_init_params(struct spi_nor *nor)
>  	spi_nor_set_erase_type(&map->erase_type[i], info->sector_size,
>  			       SPINOR_OP_SE);
>  	spi_nor_init_uniform_erase_map(map, erase_mask, params->size);
> +}
>  
> +/**
> + * spi_nor_init_params() - Initialize the flash's parameters and settings.
> + * @nor:	pointer to a 'struct spi-nor'.
> + *
> + * The flash parameters and settings are initialized based on a sequence of
> + * calls that are ordered by priority:
> + *
> + * 1/ Legacy flash parameters initialization. The initializations are done
> + *    based on nor->info data:
> + *		spi_nor_legacy_init_params()
> + *
> + * which can be overwritten by:
> + * 2/ Manufacturer flash parameters initialization. The initializations are
> + *    done based on MFR register, or when the decisions can not be done solely
> + *    based on MFR, by using specific flash_info tweeks, ->default_init():
> + *		spi_nor_manufacturer_init_params()
> + *
> + * which can be overwritten by:
> + * 3/ SFDP flash parameters initialization. JESD216 SFDP is a standard and
> + *    should be more accurate that the above.
> + *		spi_nor_sfdp_init_params()
> + *
> + *    Please not that there is a ->post_bfpt() fixup hook that can overwrite the
> + *    flash parameters and settings imediately after parsing the Basic Flash
> + *    Parameter Table.
> + */
> +static void spi_nor_init_params(struct spi_nor *nor)
> +{
> +	spi_nor_legacy_init_params(nor);
>  
>  	spi_nor_manufacturer_init_params(nor);
>  
> -	if ((info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)) &&
> -	    !(info->flags & SPI_NOR_SKIP_SFDP)) {
> -		struct spi_nor_flash_parameter sfdp_params;
> -
> -		memcpy(&sfdp_params, params, sizeof(sfdp_params));
> -
> -		if (spi_nor_parse_sfdp(nor, &sfdp_params)) {
> -			nor->addr_width = 0;
> -			nor->flags &= ~SNOR_F_4B_OPCODES;
> -		} else {
> -			memcpy(params, &sfdp_params, sizeof(*params));
> -		}
> -	}
> -
> -	return 0;
> +	if ((nor->info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)) &&
> +	    !(nor->info->flags & SPI_NOR_SKIP_SFDP))
> +		spi_nor_sfdp_init_params(nor);
>  }
>  
>  static int spi_nor_select_read(struct spi_nor *nor,
> @@ -4693,10 +4738,8 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
>  	    nor->info->flags & SPI_NOR_HAS_LOCK)
>  		nor->params.disable_block_protection = spi_nor_clear_sr_bp;
>  
> -	/* Parse the Serial Flash Discoverable Parameters table. */
> -	ret = spi_nor_init_params(nor);
> -	if (ret)
> -		return ret;
> +	/* Init flash parameters based on flash_info struct and SFDP */
> +	spi_nor_init_params(nor);
>  
>  	if (!mtd->name)
>  		mtd->name = dev_name(dev);