From 1bd3e2a823e196c6f8752be87fa2379c27df2ee1 Mon Sep 17 00:00:00 2001
From: "Wu, Josh" <Josh.wu@atmel.com>
Date: Fri, 23 Aug 2013 15:09:05 +0800
Subject: [PATCH] mtd: atmel_nand: pmecc: fix bug fail to correct bit error in
1024-bytes sector
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The PMECC use BCH algorithm to correct error. In BCH algorithm, the
primitive polynomial value is GF(2^13) for 512-bytes sector size. And it is
GF(2^14) for 1024-bytes sector size.
This patch will choose correct degree of the remainders (13 or 14) for
different sector size.
Tested in AT91SAM9X5-EK with MLC nand flash.
More detail can be refered to section 5.4.1 of:
AT91SAM ARM-based Embedded MPU Application Note
<http://www.atmel.com/Images/doc11127.pdf>
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Andreas BieÃmann <andreas.devel@googlemail.com>
---
drivers/mtd/nand/atmel_nand.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index 96aca00ebc..da83f06e47 100644
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -827,7 +827,8 @@ static int atmel_pmecc_nand_init_params(struct nand_chip *nand,
switch (mtd->writesize) {
case 2048:
case 4096:
- host->pmecc_degree = PMECC_GF_DIMENSION_13;
+ host->pmecc_degree = (sector_size == 512) ?
+ PMECC_GF_DIMENSION_13 : PMECC_GF_DIMENSION_14;
host->pmecc_cw_len = (1 << host->pmecc_degree) - 1;
host->pmecc_sector_number = mtd->writesize / sector_size;
host->pmecc_bytes_per_sector = pmecc_get_ecc_bytes(
--
2.39.5