[PATCH 1/2] mtd: spi-nor: make n_sectors in flash_info 32 bit wide

[Cyrille Pitchen]

Hi Bastian,

Le 16/01/2017 à 16:12, Bastian Stender a écrit :
> Since MRAM chips (like the Everspin mr25h40) are not sector organized
> they should be defined as n_sectors * 1 byte sectors. To be able to
> store the higher number of sectors n_sectors should be an unsigned 32
> bit integer just like sector_size.
> 

Could you comment a little bit more on what this series improves or fixes?

Swapping the info->sector_size and info->n_sectors doesn't change the value
of mtd->size:
mtd->size = info->sector_size * info->n_sectors;

info->n_sectors is used nowhere else whereas info->sector_size is only used
once more to initialized mtd->erasesize but due to the SPI_NOR_NO_ERASE
info->flags, mtd->erasesize should be never used.

However changing the type of n_sectors from u16 to unsigned int would
increase the size of the struct flash_info hence the size of the
spi_nor_ids[] array. So I don't know whether it's worth it.

However maybe swapping the values would better respect the meaning of
sector "size" and "number".

Best regards,

Cyrille

> Signed-off-by: Bastian Stender <bst at pengutronix.de>
> ---
>  drivers/mtd/spi-nor/spi-nor.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index da7cd69d4857..c8399522c69d 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -55,7 +55,7 @@ struct flash_info {
>  	 * necessarily called a "sector" by the vendor.
>  	 */
>  	unsigned	sector_size;
> -	u16		n_sectors;
> +	unsigned	n_sectors;
>  
>  	u16		page_size;
>  	u16		addr_width;
>