[U-Boot] [PATCH v3 2/2] cmd_sf: let "sf update" preserve the final part of the last sector
Gerlando Falauto
gerlando.falauto at keymile.com
Wed Jul 3 20:33:58 CEST 2013
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 at keymile.com>
Cc: Valentin Longchamp <valentin.longchamp at keymile.com>
Cc: Holger Brunck <holger.brunck at keymile.com>
Acked-by: Simon Glass <sjg at chromium.org>
---
common/cmd_sf.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/common/cmd_sf.c b/common/cmd_sf.c
index ab35a94..1141dc1 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 meaningful (len) */
if (memcmp(cmp_buf, buf, len) == 0) {
debug("Skip region %x size %zx: no change\n",
offset, len);
@@ -163,8 +165,16 @@ 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";
+ /* Write the initial part of the block from the source */
if (spi_flash_write(flash, offset, len, buf))
return "write";
+ /* If it's a partial sector, rewrite the existing part */
+ if (len != flash->sector_size) {
+ /* Rewrite the original data to the end of the sector */
+ if (spi_flash_write(flash, offset + len,
+ flash->sector_size - len, &cmp_buf[len]))
+ return "write";
+ }
return NULL;
}
--
1.8.0.1
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