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 | |
| parent | d6137badeff1ef64b4e0092ec249ebdeaeb3ff37 (diff) | |
| download | linux-041e4575f03400e045f00a823fcbbbb337de8409.tar.bz2 | |
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')
| -rw-r--r-- | drivers/mtd/mtdchar.c | 15 | ||||
| -rw-r--r-- | drivers/mtd/nand/nand_base.c | 9 |
2 files changed, 23 insertions, 1 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; } diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 237d7daa189c..5418d27122c4 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -1750,6 +1750,7 @@ static int nand_do_read_oob(struct mtd_info *mtd, loff_t from, { 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 @@ static int nand_do_read_oob(struct mtd_info *mtd, loff_t from, 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 @@ static int nand_do_read_oob(struct mtd_info *mtd, loff_t from, } ops->oobretlen = ops->ooblen; - return 0; + + if (mtd->ecc_stats.failed - stats.failed) + return -EBADMSG; + + return mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0; } /** |