From: "Kai Stuhlemmer (ebee Engineering)" kai.stuhlemmer@ebee.de
Not correcting anything in case of empty ECC data area is not an appropriate strategy, because an uncorrected bit-flip in an empty sector may cause upper layers (namely UBI) fail to work properly. Therefore the approach chosen in Linux kernel and other u-boot mtd drivers has been adopted, where a heuristic implemented by nand_check_erased_ecc_chunk() is used in order to detect and correct empty sectors.
Tested with sama5d3_xplained and sam9x60-ek.
Signed-off-by: Kai Stuhlemmer (ebee Engineering) kai.stuhlemmer@ebee.de Tested-by: Tudor Ambarus tudor.ambarus@microchip.com [ta: reorder if conditions, change commit subject, s/uint8_t/u8.] Signed-off-by: Tudor Ambarus tudor.ambarus@microchip.com --- drivers/mtd/nand/raw/atmel_nand.c | 37 +++++++++++++++---------------- 1 file changed, 18 insertions(+), 19 deletions(-)
diff --git a/drivers/mtd/nand/raw/atmel_nand.c b/drivers/mtd/nand/raw/atmel_nand.c index abc432c862..6541c3bea8 100644 --- a/drivers/mtd/nand/raw/atmel_nand.c +++ b/drivers/mtd/nand/raw/atmel_nand.c @@ -493,21 +493,9 @@ static int pmecc_correction(struct mtd_info *mtd, u32 pmecc_stat, uint8_t *buf, { struct nand_chip *nand_chip = mtd_to_nand(mtd); struct atmel_nand_host *host = nand_get_controller_data(nand_chip); - int i, err_nbr, eccbytes; - uint8_t *buf_pos; - - /* SAMA5D4 PMECC IP can correct errors for all 0xff page */ - if (host->pmecc_version >= PMECC_VERSION_SAMA5D4) - goto normal_check; - - eccbytes = nand_chip->ecc.bytes; - for (i = 0; i < eccbytes; i++) - if (ecc[i] != 0xff) - goto normal_check; - /* Erased page, return OK */ - return 0; + int i, err_nbr; + u8 *buf_pos, *ecc_pos;
-normal_check: for (i = 0; i < host->pmecc_sector_number; i++) { err_nbr = 0; if (pmecc_stat & 0x1) { @@ -518,15 +506,26 @@ normal_check: pmecc_get_sigma(mtd);
err_nbr = pmecc_err_location(mtd); - if (err_nbr == -1) { + if (err_nbr >= 0) { + pmecc_correct_data(mtd, buf_pos, ecc, i, + host->pmecc_bytes_per_sector, + err_nbr); + } else if (host->pmecc_version < PMECC_VERSION_SAMA5D4) { + ecc_pos = ecc + i * host->pmecc_bytes_per_sector; + + err_nbr = nand_check_erased_ecc_chunk( + buf_pos, host->pmecc_sector_size, + ecc_pos, host->pmecc_bytes_per_sector, + NULL, 0, host->pmecc_corr_cap); + } + + if (err_nbr < 0) { dev_err(mtd->dev, "PMECC: Too many errors\n"); mtd->ecc_stats.failed++; return -EBADMSG; - } else { - pmecc_correct_data(mtd, buf_pos, ecc, i, - host->pmecc_bytes_per_sector, err_nbr); - mtd->ecc_stats.corrected += err_nbr; } + + mtd->ecc_stats.corrected += err_nbr; } pmecc_stat >>= 1; }