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 --- 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 96aca00..da83f06 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(