[PATCH 1/2] mtd: nand: Base BCH ECC bytes on required strength

[Aaron Sierra]

From: Jordan Friendshuh <jfriendshuh at xes-inc.com>

NAND devices with page sizes over 4 KiB require more than 4-bits of ECC
coverage. This patch calculates the value of ecc_bytes based on a still
assumed 512-byte step size (13-bits) and the ecc_strength.

Example:
Micron M73A devices (8 KiB page) require 8-bit ECC per 512-byte

Signed-off-by: Jordan Friendshuh <jfriendshuh at xes-inc.com>
Signed-off-by: Aaron Sierra <asierra at xes-inc.com>
---
 drivers/mtd/nand/nand_base.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 4f3e80c..9fdfed4 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -4001,7 +4001,7 @@ int nand_scan_tail(struct mtd_info *mtd)
 		 */
 		if (!ecc->size && (mtd->oobsize >= 64)) {
 			ecc->size = 512;
-			ecc->bytes = 7;
+			ecc->bytes = DIV_ROUND_UP(13 * ecc->strength, 8);
 		}
 		ecc->priv = nand_bch_init(mtd, ecc->size, ecc->bytes,
 					       &ecc->layout);
-- 
1.9.1