Hi,
On Thu, 25 May 2017 23:33:43 +0000
Darwin Dingel <darwin.din...@alliedtelesis.co.nz> wrote:
> Hi,
>
> We are also having the same problem where the IFC (nand flash) was
> reporting ECC uncorrectable errors on single bitflips with erased pages.
> Applying this patch with some minor modifications seems to solve our
> issue. We are still doing more testing but recent results looks promising.
Pavel, can you send a v2 fixing these problems?
Thanks,
Boris
>
> Our kernel is 4.4.6 so we have to modify it a bit to fit the old ECC
> layout structure. We just have a few comments about the patch:
>
> > - if (!is_blank(mtd, bufnum))
> > - ctrl->nand_stat |=
> > - IFC_NAND_EVTER_STAT_ECCER;
> > - break;
> > + ctrl->nand_stat |= IFC_NAND_EVTER_STAT_ECCER;
>
> Added 'error = 0' after setting the flag since no error was actually
> corrected.
>
> > - 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_OPC)
> > mtd->ecc_stats.failed++;
> > +
> > + if (ctrl->nand_stat & IFC_NAND_EVTER_STAT_ECCER) {
> > + int res;
> > +
> > + if (!oob_required)
> > + fsl_ifc_read_buf(mtd, chip->oob_poi, mtd->oobsize);
> > +
> > + res = check_erased_page(chip, buf);
> > + return res;
> > + }
>
> We have to do the check IFC_NAND_EVTER_STAT_ECCER first because the
> condition (ctrl->nand_stat != IFC_NAND_EVTER_STAT_OPC) will never be
> true since IFC always sets IFC_NAND_EVTER_STAT_ECCER on empty pages.
> Incrementing failed stats first before doing check_erased_page() makes
> nand_read() report ECC error all time.
>
> Our exact modification was:
> 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++;
>
> Because check_erased_page() will be updating the failed stat anyway.
>
>
> Cheers,
> Darwin
