[PATCH 1/2] mtd: nand: use a lower value for badblockbits when working with MLC NAND

[rnd4@dave-tech.it]

From: Andrea Scian <andrea.scian@dave.eu>

MLC NANDs have more bit flips that SLC. When looking for bad block
marker we have a lot of false positive if we check for the whole byte. To
avoid this tolerate a few (4 here) bit flips for byte.

Signed-off-by: Andrea Scian <andrea.scian@dave.eu>
---
 drivers/mtd/nand/nand_base.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index dfcd0a5..bdca223 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -3315,7 +3315,10 @@ ident_done:
 		chip->chip_shift += 32 - 1;
 	}
 
-	chip->badblockbits = 8;
+	if (nand_is_slc(chip))
+		chip->badblockbits = 8;
+	else
+		chip->badblockbits = 4;
 	chip->erase_cmd = single_erase_cmd;
 
 	/* Do not replace user supplied command function! */
-- 
1.7.9.5