[U-Boot] [PATCH v2 2/2] cmd_sf: "sf update" preserve the final part of the last sector

Jagan Teki
2013-07-03T15:04:24Z

Hi,

Thanks for the v2.

On Fri, Jun 28, 2013 at 1:13 PM, Gerlando Falauto
<gerlando.falauto@keymile.com> wrote:
> Since "sf update" erases the last block as a whole, but only rewrites
> the meaningful initial part of it, the rest would be left erased,
> potentially erasing meaningful information.
> So, as a safety measure, have it rewrite the original content.
>
> Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
> Cc: Valentin Longchamp <valentin.longchamp@keymile.com>
> Cc: Holger Brunck <holger.brunck@keymile.com>
> Acked-by: Simon Glass <sjg@chromium.org>
> ---
> common/cmd_sf.c | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/common/cmd_sf.c b/common/cmd_sf.c
> index ab35a94..fb87d24 100644
> --- a/common/cmd_sf.c
> +++ b/common/cmd_sf.c
> @@ -152,8 +152,10 @@ static const char *spi_flash_update_block(struct spi_flash *flash, u32 offset,
> {
> debug("offset=%#x, sector_size=%#x, len=%#zx\n",
> offset, flash->sector_size, len);
> - if (spi_flash_read(flash, offset, len, cmp_buf))
> + /* Read the entire sector so to allow for rewriting */
> + if (spi_flash_read(flash, offset, flash->sector_size, cmp_buf))
> return "read";
> + /* Compare only what is meningful (len) */
> if (memcmp(cmp_buf, buf, len) == 0) {
> debug("Skip region %x size %zx: no change\n",
> offset, len);
> @@ -163,6 +165,17 @@ static const char *spi_flash_update_block(struct spi_flash *flash, u32 offset,
> /* Erase the entire sector */
> if (spi_flash_erase(flash, offset, flash->sector_size))
> return "erase";
> + /* If it's a partial sector, preserve the existing part */
> + if (len != flash->sector_size) {
> + /* Overwrite the first part of the sector with input data */
> + memcpy(cmp_buf, buf, len);

Can comment about memcpy() here, as Simon is also asked in v1
http://patchwork.ozlabs.org/patch/150468/

--
Thanks,
Jagan.

> + /* Rewrite the whole sector with original data at the end */
> + if (spi_flash_write(flash, offset, flash->sector_size,
> + cmp_buf))
> + return "write";
> + return NULL;
> + }
> + /* Rewrite the whole block from the source */
> if (spi_flash_write(flash, offset, len, buf))
> return "write";
> return NULL;
> --
> 1.7.10.1
>