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authorMike Dunn <mikedunn@newsguy.com>2012-04-25 12:06:11 -0700
committerDavid Woodhouse <David.Woodhouse@intel.com>2012-05-13 23:14:23 -0500
commitedbc4540e02c201bdd4f4d498ebb6ed517fd36e2 (patch)
tree403ee7318cb1218a224885d048781e35f2128a22 /drivers/mtd/onenand
parente2788c98b98269a3131bffd2b57599280d7abd73 (diff)
downloadop-kernel-dev-edbc4540e02c201bdd4f4d498ebb6ed517fd36e2.zip
op-kernel-dev-edbc4540e02c201bdd4f4d498ebb6ed517fd36e2.tar.gz
mtd: driver _read() returns max_bitflips; mtd_read() returns -EUCLEAN
The drivers' _read() method, absent an error, returns a non-negative integer indicating the maximum number of bit errors that were corrected in any one region comprising an ecc step. MTD returns -EUCLEAN if this is >= bitflip_threshold, 0 otherwise. If bitflip_threshold is zero, the comparison is not made since these devices lack ECC and always return zero in the non-error case (thanks Brian)¹. Note that this is a subtle change to the driver interface. This and the preceding patches in this set were tested with ubi on top of the nandsim and docg4 devices, running the ubi test io_basic from mtd-utils. ¹ http://lists.infradead.org/pipermail/linux-mtd/2012-March/040468.html Signed-off-by: Mike Dunn <mikedunn@newsguy.com> Acked-by: Robert Jarzmik <robert.jarzmik@free.fr> Acked-by: Brian Norris <computersforpeace@gmail.com> Ivan Djelic <ivan.djelic@parrot.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Diffstat (limited to 'drivers/mtd/onenand')
-rw-r--r--drivers/mtd/onenand/onenand_base.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index b3ce12e..7153e0d2 100644
--- a/drivers/mtd/onenand/onenand_base.c
+++ b/drivers/mtd/onenand/onenand_base.c
@@ -1201,7 +1201,8 @@ static int onenand_mlc_read_ops_nolock(struct mtd_info *mtd, loff_t from,
if (mtd->ecc_stats.failed - stats.failed)
return -EBADMSG;
- return mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;
+ /* return max bitflips per ecc step; ONENANDs correct 1 bit only */
+ return mtd->ecc_stats.corrected != stats.corrected ? 1 : 0;
}
/**
@@ -1333,7 +1334,8 @@ static int onenand_read_ops_nolock(struct mtd_info *mtd, loff_t from,
if (mtd->ecc_stats.failed - stats.failed)
return -EBADMSG;
- return mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;
+ /* return max bitflips per ecc step; ONENANDs correct 1 bit only */
+ return mtd->ecc_stats.corrected != stats.corrected ? 1 : 0;
}
/**
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