xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

mtd: nand: handle ECC errors in OOB

Browse Source 
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>
This commit is contained in:
Brian Norris
2011-06-23 16:45:24 -07:00
committed by Artem Bityutskiy
parent d6137badef
commit 041e4575f0
2 changed files with 23 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/mtd/mtdchar.c
View File

@@ -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;
}