Re: [PATCH 06/41] mtd: spi-nor: default page_size to 256 bytes

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Michael Walle <mwalle@kernel.org>
Cc: Tudor Ambarus <tudor.ambarus@linaro.org>,
	Pratyush Yadav <pratyush@kernel.org>,
	Michael Walle <michael@walle.cc>,
	Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org
Subject: Re: [PATCH 06/41] mtd: spi-nor: default page_size to 256 bytes
Date: Mon, 7 Aug 2023 15:47:54 +0200	[thread overview]
Message-ID: <20230807154754.70e994fa@xps-13> (raw)
In-Reply-To: <20230807-mtd-flash-info-db-rework-v1-6-3d3d5bef4ba4@kernel.org>

Hi Michael,

mwalle@kernel.org wrote on Mon, 07 Aug 2023 15:21:00 +0200:

> The INFO() macro always set the page_size to 256 bytes. Make that an
> optinal parameter. This default is a sane one for all older flashes,

optional

> newer ones will set the page size by its SFDP tables anyway.
> 
> Signed-off-by: Michael Walle <mwalle@kernel.org>
> ---
>  drivers/mtd/spi-nor/core.c | 7 +------
>  drivers/mtd/spi-nor/core.h | 8 ++++++--
>  2 files changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index c504a5af4032..138bc1e0a67c 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -2017,11 +2017,6 @@ static const struct spi_nor_manufacturer *manufacturers[] = {
>  static const struct flash_info spi_nor_generic_flash = {
>  	.name = "spi-nor-generic",
>  	.n_banks = 1,
> -	/*
> -	 * JESD216 rev A doesn't specify the page size, therefore we need a
> -	 * sane default.
> -	 */
> -	.page_size = 256,
>  	.parse_sfdp = true,
>  };
>  
> @@ -3000,7 +2995,7 @@ static void spi_nor_init_default_params(struct spi_nor *nor)
>  	params->writesize = 1;
>  	params->size = info->size;
>  	params->bank_size = params->size;
> -	params->page_size = info->page_size;
> +	params->page_size = info->page_size ?: SPI_NOR_DEFAULT_PAGE_SIZE;

Would you mind clarifying this? It does not look right, while
perhaps it is. But TBH, I have no idea what params->page_size will be
after this assignment.

>  
>  	if (!(info->flags & SPI_NOR_NO_FR)) {
>  		/* Default to Fast Read for DT and non-DT platform devices. */
> diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
> index 12c35409493b..25bc18197614 100644
> --- a/drivers/mtd/spi-nor/core.h
> +++ b/drivers/mtd/spi-nor/core.h
> @@ -10,6 +10,11 @@
>  #include "sfdp.h"
>  
>  #define SPI_NOR_MAX_ID_LEN	6
> +/*
> + * 256 bytes is a sane default for most older flashes. Newer flashes will
> + * have the page size defined within their SFDP tables.
> + */
> +#define SPI_NOR_DEFAULT_PAGE_SIZE 256
>  
>  /* Standard SPI NOR flash operations. */
>  #define SPI_NOR_READID_OP(naddr, ndummy, buf, len)			\
> @@ -447,7 +452,7 @@ struct spi_nor_fixups {
>   * @sector_size:    the size listed here is what works with SPINOR_OP_SE, which
>   *                  isn't necessarily called a "sector" by the vendor.
>   * @n_banks:        the number of banks.
> - * @page_size:      the flash's page size.
> + * @page_size:      (optional) the flash's page size. Defaults to 256.
>   * @addr_nbytes:    number of address bytes to send.
>   *
>   * @parse_sfdp:     true when flash supports SFDP tables. The false value has no
> @@ -558,7 +563,6 @@ struct flash_info {
>  #define SPI_NOR_GEOMETRY(_sector_size, _n_sectors, _n_banks)		\
>  	.size = (_sector_size) * (_n_sectors),				\
>  	.sector_size = (_sector_size),					\
> -	.page_size = 256,						\
>  	.n_banks = (_n_banks)
>  
>  /* Used when the "_ext_id" is two bytes at most */
> 

Otherwise, lgtm.

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>

Thanks,
Miquèl

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