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authorShmulik Ladkani <shmulik@jungo.com>2012-06-08 18:29:06 +0300
committerDavid Woodhouse <David.Woodhouse@intel.com>2012-06-09 12:02:04 +0100
commitea3b2ea24ef0f2ef9c6795b19cff456195b6728a (patch)
tree8a1c645a82a7329631166cf6e3f63857d401da40
parentcfaf025112d3856637ff34a767ef785ef5cf2ca9 (diff)
downloadlinux-stericsson-ea3b2ea24ef0f2ef9c6795b19cff456195b6728a.tar.gz
mtd: nand: initialize bitflip_threshold prior to BBT scanning
As of edbc454 [mtd: driver _read() returns max_bitflips; mtd_read() returns -EUCLEAN], 'mtd->bitflip_threshold' must be set for mtd devices having ECC, prior any 'mtd_read()' call. Otherwise, 'mtd_read()' will falsely return -EUCLEAN. Normally, 'mtd->bitflip_threshold' is initialized when the MTD is added. However, this is too late for NAND MTDs, as 'scan_bbt()' is invoked prior the existing initialization of 'mtd->bitflip_threshold'. This is a problem since 'scan_bbt()' calls 'mtd_read()', in the case of a flash-based bad block table. It resulted in a falsely reported bitflips indication during BBT read, which lead to constant scrubbing of the flash BBT blocks. Initialize 'mtd->bitflip_threshold' to its default value (if not already set by the driver), prior to invocation of 'scan_bbt()'. Reported-by: Sascha Hauer <s.hauer@pengutronix.de> Tested-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
-rw-r--r--drivers/mtd/nand/nand_base.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index d47586cf64ce..a11253a0fcab 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -3501,6 +3501,13 @@ int nand_scan_tail(struct mtd_info *mtd)
/* propagate ecc info to mtd_info */
mtd->ecclayout = chip->ecc.layout;
mtd->ecc_strength = chip->ecc.strength;
+ /*
+ * Initialize bitflip_threshold to its default prior scan_bbt() call.
+ * scan_bbt() might invoke mtd_read(), thus bitflip_threshold must be
+ * properly set.
+ */
+ if (!mtd->bitflip_threshold)
+ mtd->bitflip_threshold = mtd->ecc_strength;
/* Check, if we should skip the bad block table scan */
if (chip->options & NAND_SKIP_BBTSCAN)