diff options
| author | Brian Norris <computersforpeace@gmail.com> | 2011-06-23 16:45:24 -0700 |
|---|---|---|
| committer | Artem Bityutskiy <artem.bityutskiy@intel.com> | 2011-09-11 15:02:14 +0300 |
| commit | 041e4575f03400e045f00a823fcbbbb337de8409 (patch) | |
| tree | 3fa062bee497a7ff13d908bf2204de4ec04888da /drivers/mtd/mtdchar.c | |
| parent | d6137badeff1ef64b4e0092ec249ebdeaeb3ff37 (diff) | |
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>
Diffstat (limited to 'drivers/mtd/mtdchar.c')
| -rw-r--r-- | drivers/mtd/mtdchar.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c index c60067b1f07a..d5924635ead5 100644 --- a/drivers/mtd/mtdchar.c +++ b/drivers/mtd/mtdchar.c @@ -473,6 +473,21 @@ static int mtd_do_readoob(struct mtd_info *mtd, uint64_t start, ret = -EFAULT; kfree(ops.oobbuf); + + /* + * NAND returns -EBADMSG on ECC errors, but it returns the OOB + * data. For our userspace tools it is important to dump areas + * with ECC errors! + * For kernel internal usage it also might return -EUCLEAN + * to signal the caller that a bitflip has occured and has + * been corrected by the ECC algorithm. + * + * Note: most NAND ECC algorithms do not calculate ECC + * for the OOB area. + */ + if (ret == -EUCLEAN || ret == -EBADMSG) + return 0; + return ret; } |