mtd: atmel_nand: pmecc: fix failure to correct bit error in 1024-bytes sector

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=2fa831f9db1f1a13960f4ea0fd0454402717b453
Commit:     2fa831f9db1f1a13960f4ea0fd0454402717b453
Parent:     eedeac3ce94e2a3d4ff28974221b9f309358d8de
Author:     Josh Wu <josh.wu at atmel.com>
AuthorDate: Mon Aug 19 18:05:44 2013 +0800
Committer:  David Woodhouse <David.Woodhouse at intel.com>
CommitDate: Fri Aug 30 21:41:39 2013 +0100

    mtd: atmel_nand: pmecc: fix failure to correct bit error in 1024-bytes sector
    
    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 found in §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 at atmel.com>
    Signed-off-by: Artem Bityutskiy <artem.bityutskiy at linux.intel.com>
    Signed-off-by: David Woodhouse <David.Woodhouse at intel.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 0e365da..8b2eb3e 100644
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -1204,7 +1204,8 @@ static int __init atmel_pmecc_nand_init_params(struct platform_device *pdev,
 	/* set ECC page size and oob layout */
 	switch (mtd->writesize) {
 	case 2048:
-		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(