diff options
| -rw-r--r-- | drivers/mtd/nand/raw/omap_gpmc.c | 45 |
1 files changed, 36 insertions, 9 deletions
diff --git a/drivers/mtd/nand/raw/omap_gpmc.c b/drivers/mtd/nand/raw/omap_gpmc.c index 530574898c..107447f9df 100644 --- a/drivers/mtd/nand/raw/omap_gpmc.c +++ b/drivers/mtd/nand/raw/omap_gpmc.c @@ -507,19 +507,45 @@ static int omap_correct_data_bch(struct mtd_info *mtd, uint8_t *dat, /* check calculated ecc */ for (i = 0; i < ecc->bytes && !ecc_flag; i++) { if (calc_ecc[i] != 0x00) - ecc_flag = 1; + goto not_ecc_match; } - if (!ecc_flag) - return 0; + return 0; +not_ecc_match: - /* check for whether its a erased-page */ - ecc_flag = 0; - for (i = 0; i < ecc->bytes && !ecc_flag; i++) { + /* check for whether it's an erased-page */ + for (i = 0; i < ecc->bytes; i++) { if (read_ecc[i] != 0xff) - ecc_flag = 1; + goto not_erased; + } + for (i = 0; i < SECTOR_BYTES; i++) { + if (dat[i] != 0xff) + goto not_erased; + } + return 0; +not_erased: + + /* + * Check for whether it's an erased page with a correctable + * number of bitflips. Erased pages have all 1's in the data, + * so we just compute the number of 0 bits in the data and + * see if it's under the correction threshold. + * + * NOTE: The check for a perfect erased page above is faster for + * the more common case, even though it's logically redundant. + */ + for (i = 0; i < ecc->bytes; i++) + error_count += hweight8(~read_ecc[i]); + + for (i = 0; i < SECTOR_BYTES; i++) + error_count += hweight8(~dat[i]); + + if (error_count <= ecc->strength) { + memset(read_ecc, 0xFF, ecc->bytes); + memset(dat, 0xFF, SECTOR_BYTES); + debug("nand: %u bit-flip(s) corrected in erased page\n", + error_count); + return error_count; } - if (!ecc_flag) - return 0; /* * while reading ECC result we read it in big endian. @@ -539,6 +565,7 @@ static int omap_correct_data_bch(struct mtd_info *mtd, uint8_t *dat, } /* use elm module to check for errors */ elm_config(bch_type); + error_count = 0; err = elm_check_error(calc_ecc, bch_type, &error_count, error_loc); if (err) return err; |