The default NAND read functions are relying on an underlying controller to correct bitflips, but some of those controller cannot properly fix bitflips in erased pages. In case of ECC failures, check if the page of subpage is empty before reporting an ECC failure.
Signed-off-by: Boris Brezillon <[email protected]> --- drivers/mtd/nand/nand_base.c | 63 ++++++++++++++++++++++++++++++++++++++------ 1 file changed, 55 insertions(+), 8 deletions(-) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 1542ea7..d527c73 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -1396,6 +1396,19 @@ static int nand_read_subpage(struct mtd_info *mtd, struct nand_chip *chip, stat = chip->ecc.correct(mtd, p, &chip->buffers->ecccode[i], &chip->buffers->ecccalc[i]); if (stat < 0) { + /* check for empty pages with bitflips */ + int col = (int)(p - bufpoi); + + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, col, -1); + chip->read_buf(mtd, p, chip->ecc.size); + stat = nand_check_erased_ecc_chunk(p, chip->ecc.size, + &chip->buffers->ecccode[i], + chip->ecc.bytes, + NULL, 0, + chip->ecc.strength); + } + + if (stat < 0) { mtd->ecc_stats.failed++; } else { mtd->ecc_stats.corrected += stat; @@ -1445,6 +1458,16 @@ static int nand_read_page_hwecc(struct mtd_info *mtd, struct nand_chip *chip, stat = chip->ecc.correct(mtd, p, &ecc_code[i], &ecc_calc[i]); if (stat < 0) { + /* check for empty pages with bitflips */ + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, i, -1); + chip->read_buf(mtd, p, eccsize); + stat = nand_check_erased_ecc_chunk(p, eccsize, + &ecc_code[i], eccbytes, + NULL, 0, + chip->ecc.strength); + } + + if (stat < 0) { mtd->ecc_stats.failed++; } else { mtd->ecc_stats.corrected += stat; @@ -1495,7 +1518,18 @@ static int nand_read_page_hwecc_oob_first(struct mtd_info *mtd, chip->read_buf(mtd, p, eccsize); chip->ecc.calculate(mtd, p, &ecc_calc[i]); - stat = chip->ecc.correct(mtd, p, &ecc_code[i], NULL); + stat = chip->ecc.correct(mtd, p, &ecc_code[i], &ecc_calc[i]); + if (stat < 0) { + /* check for empty pages with bitflips */ + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, + i + mtd->oobsize, -1); + chip->read_buf(mtd, p, eccsize); + stat = nand_check_erased_ecc_chunk(p, eccsize, + &ecc_code[i], eccbytes, + NULL, 0, + chip->ecc.strength); + } + if (stat < 0) { mtd->ecc_stats.failed++; } else { @@ -1523,6 +1557,8 @@ static int nand_read_page_syndrome(struct mtd_info *mtd, struct nand_chip *chip, int i, eccsize = chip->ecc.size; int eccbytes = chip->ecc.bytes; int eccsteps = chip->ecc.steps; + int eccstepsize = eccsize + eccbytes + chip->ecc.prepad + + chip->ecc.postpad; uint8_t *p = buf; uint8_t *oob = chip->oob_poi; unsigned int max_bitflips = 0; @@ -1542,19 +1578,30 @@ static int nand_read_page_syndrome(struct mtd_info *mtd, struct nand_chip *chip, chip->read_buf(mtd, oob, eccbytes); stat = chip->ecc.correct(mtd, p, oob, NULL); - if (stat < 0) { - mtd->ecc_stats.failed++; - } else { - mtd->ecc_stats.corrected += stat; - max_bitflips = max_t(unsigned int, max_bitflips, stat); - } - oob += eccbytes; if (chip->ecc.postpad) { chip->read_buf(mtd, oob, chip->ecc.postpad); oob += chip->ecc.postpad; } + + if (stat < 0) { + /* check for empty pages with bitflips */ + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, i * eccstepsize, -1); + chip->read_buf(mtd, p, chip->ecc.size); + stat = nand_check_erased_ecc_chunk(p, chip->ecc.size, + oob - eccstepsize, + eccstepsize, + NULL, 0, + chip->ecc.strength); + } + + if (stat < 0) { + mtd->ecc_stats.failed++; + } else { + mtd->ecc_stats.corrected += stat; + max_bitflips = max_t(unsigned int, max_bitflips, stat); + } } /* Calculate remaining oob bytes */ -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
