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mtd: nand: fsl_ifc: fix handing of bit flips in erased pages 

If we see unrecoverable ECC error, we need to count number of bitflips
from all-ones and report correctable/uncorrectable according to
that. Otherwise we report ECC failed on erased flash with single bit error.

Signed-off-by: Pavel Machek <pavel@denx.de>
Reported-by: Darwin Dingel <Darwin.Dingel@alliedtelesis.co.nz>
Acked-by: Darwin Dingel <Darwin.Dingel@alliedtelesis.co.nz>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This commit is contained in:
Boris Brezillon 2017-06-10 12:09:05 +02:00
parent 30ee809e98
commit d45e5316e6
1 changed files with 42 additions and 35 deletions
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77
drivers/mtd/nand/fsl_ifc_nand.c
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@ -171,34 +171,6 @@ static void set_addr(struct mtd_info *mtd, int column, int page_addr, int oob)
ifc_nand_ctrl->index += mtd->writesize;
}
static int is_blank(struct mtd_info *mtd, unsigned int bufnum)
{
struct nand_chip *chip = mtd_to_nand(mtd);
struct fsl_ifc_mtd *priv = nand_get_controller_data(chip);
u8 __iomem *addr = priv->vbase + bufnum * (mtd->writesize * 2);
u32 __iomem *mainarea = (u32 __iomem *)addr;
u8 __iomem *oob = addr + mtd->writesize;
struct mtd_oob_region oobregion = { };
int i, section = 0;
for (i = 0; i < mtd->writesize / 4; i++) {
if (__raw_readl(&mainarea[i]) != 0xffffffff)
return 0;
}
mtd_ooblayout_ecc(mtd, section++, &oobregion);
while (oobregion.length) {
for (i = 0; i < oobregion.length; i++) {
if (__raw_readb(&oob[oobregion.offset + i]) != 0xff)
return 0;
}
mtd_ooblayout_ecc(mtd, section++, &oobregion);
}
return 1;
}
/* returns nonzero if entire page is blank */
static int check_read_ecc(struct mtd_info *mtd, struct fsl_ifc_ctrl *ctrl,
u32 *eccstat, unsigned int bufnum)
@ -274,16 +246,14 @@ static void fsl_ifc_run_command(struct mtd_info *mtd)
if (errors == 15) {
/*
* Uncorrectable error.
* OK only if the whole page is blank.
* We'll check for blank pages later.
*
* We disable ECCER reporting due to...
* erratum IFC-A002770 -- so report it now if we
* see an uncorrectable error in ECCSTAT.
*/
if (!is_blank(mtd, bufnum))
ctrl->nand_stat |=
IFC_NAND_EVTER_STAT_ECCER;
break;
ctrl->nand_stat |= IFC_NAND_EVTER_STAT_ECCER;
continue;
}
mtd->ecc_stats.corrected += errors;
@ -678,6 +648,39 @@ static int fsl_ifc_wait(struct mtd_info *mtd, struct nand_chip *chip)
return nand_fsr | NAND_STATUS_WP;
}
/*
* The controller does not check for bitflips in erased pages,
* therefore software must check instead.
*/
static int check_erased_page(struct nand_chip *chip, u8 *buf)
{
struct mtd_info *mtd = nand_to_mtd(chip);
u8 *ecc = chip->oob_poi;
const int ecc_size = chip->ecc.bytes;
const int pkt_size = chip->ecc.size;
int i, res, bitflips = 0;
struct mtd_oob_region oobregion = { };
mtd_ooblayout_ecc(mtd, 0, &oobregion);
ecc += oobregion.offset;
for (i = 0; i < chip->ecc.steps; ++i) {
res = nand_check_erased_ecc_chunk(buf, pkt_size, ecc, ecc_size,
NULL, 0,
chip->ecc.strength);
if (res < 0)
mtd->ecc_stats.failed++;
else
mtd->ecc_stats.corrected += res;
bitflips = max(res, bitflips);
buf += pkt_size;
ecc += ecc_size;
}
return bitflips;
}
static int fsl_ifc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
uint8_t *buf, int oob_required, int page)
{
@ -689,8 +692,12 @@ static int fsl_ifc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
if (oob_required)
fsl_ifc_read_buf(mtd, chip->oob_poi, mtd->oobsize);
if (ctrl->nand_stat & IFC_NAND_EVTER_STAT_ECCER)
dev_err(priv->dev, "NAND Flash ECC Uncorrectable Error\n");
if (ctrl->nand_stat & IFC_NAND_EVTER_STAT_ECCER) {
if (!oob_required)
fsl_ifc_read_buf(mtd, chip->oob_poi, mtd->oobsize);
return check_erased_page(chip, buf);
}
if (ctrl->nand_stat != IFC_NAND_EVTER_STAT_OPC)
mtd->ecc_stats.failed++;