mtd: nand: handle ECC errors in OOB
While the standard NAND OOB functions do not do ECC on the spare area,
it is possible for a driver to supply its own OOB ECC functions (e.g., HW
ECC). nand_do_read_oob should act like nand_do_read_ops in checking the
ECC stats and returning -EBADMSG or -EUCLEAN on uncorrectable errors or
correctable bitflips, respectively. These error codes could be used in
flash-based BBT code or in YAFFS, for example.
Doing this, however, messes with the behavior of mtd_do_readoob. Now,
mtd_do_readoob should check whether we had -EUCLEAN or -EBADMSG errors
and discard those as "non-fatal" so that the ioctls can still succeed
with (possibly uncorrected) data.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 237d7da..5418d27 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -1750,6 +1750,7 @@
{
int page, realpage, chipnr, sndcmd = 1;
struct nand_chip *chip = mtd->priv;
+ struct mtd_ecc_stats stats;
int blkcheck = (1 << (chip->phys_erase_shift - chip->page_shift)) - 1;
int readlen = ops->ooblen;
int len;
@@ -1758,6 +1759,8 @@
DEBUG(MTD_DEBUG_LEVEL3, "%s: from = 0x%08Lx, len = %i\n",
__func__, (unsigned long long)from, readlen);
+ stats = mtd->ecc_stats;
+
if (ops->mode == MTD_OOB_AUTO)
len = chip->ecc.layout->oobavail;
else
@@ -1828,7 +1831,11 @@
}
ops->oobretlen = ops->ooblen;
- return 0;
+
+ if (mtd->ecc_stats.failed - stats.failed)
+ return -EBADMSG;
+
+ return mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;
}
/**