Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d45e5316 authored by Boris Brezillon's avatar Boris Brezillon
Browse files

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: default avatarPavel Machek <pavel@denx.de>
Reported-by: default avatarDarwin Dingel <Darwin.Dingel@alliedtelesis.co.nz>
Acked-by: default avatarDarwin Dingel <Darwin.Dingel@alliedtelesis.co.nz>
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
parent 30ee809e

drivers/mtd/nand/fsl_ifc_nand.c

+42 −35
Original line number Diff line number Diff line
@@ -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++;