[U-Boot] [PATCH] cfi_flash: fix bug with flash banks with different sector numbers

[Detlev Zundel <dzu@denx.de>]

Martin Krause <martin.krause@tqs.de> writes:

> The function find_sector() does not take into account if the flash bank
> has changed since the last call. This could lead to illegal accesses inside
> and beyond the flash_info_t info strcture. For example if the current
> flash bank has less sectors than the last used flash bank.
>
> This patch adds two cheks. One that insures, that the current sector does
> not exceed the allowed maximum (which is always a good idea). And one that
> checks if the current access is to the same flash bank as the last access.
> If not, the search loop will start with sector 0.
>
> Signed-off-by: Martin Krause <martin.krause@tqs.de>
> ---
>  drivers/mtd/cfi_flash.c |    5 +++++
>  1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
> index dd394a8..0909fe7 100644
> --- a/drivers/mtd/cfi_flash.c
> +++ b/drivers/mtd/cfi_flash.c
> @@ -744,8 +744,12 @@ static void flash_add_byte (flash_info_t * info, cfiword_t * cword, uchar c)
>  static flash_sect_t find_sector (flash_info_t * info, ulong addr)
>  {
>  	static flash_sect_t saved_sector = 0; /* previously found sector */
> +	static flash_info_t *saved_info = 0; /* previously used flash bank */
>  	flash_sect_t sector = saved_sector;
>  
> +	if ((info != saved_info) || (sector >= info->sector_count))
> +		sector = 0;
> +
>  	while ((info->start[sector] < addr)
>  			&& (sector < info->sector_count - 1))
>  		sector++;
> @@ -757,6 +761,7 @@ static flash_sect_t find_sector (flash_info_t * info, ulong addr)
>  		sector--;
>  
>  	saved_sector = sector;
> +	saved_info = info;
>  	return sector;
>  }

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DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
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