| Message ID | 1465507075-9447-1-git-send-email-kdasu.kdev@gmail.com |
|---|---|
| State | Accepted |
| Commit | 02b88eea9f9cab82f5f4be234c64466503021f82 |
| Headers | show |
On Thu, 9 Jun 2016 17:17:54 -0400 Kamal Dasu <kdasu.kdev@gmail.com> wrote: > Check for erased page bitflips in a page. And if well within > threshold return data as all 0xff. Apply sw check for controller > version < 7.2. Controller vesion >= 7.2 has hw support. > > Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com> Applied both. Thanks, Boris > --- > V3 changes > Return the max bitflips from a sector within a page > V2 changes > Added use of nand_check_erased_ecc_chunk > Restrict change to older controller < 7.2 > --- > > drivers/mtd/nand/brcmnand/brcmnand.c | 62 ++++++++++++++++++++++++++++++++++++ > 1 file changed, 62 insertions(+) > > diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c > index b76ad7c..7ee9617 100644 > --- a/drivers/mtd/nand/brcmnand/brcmnand.c > +++ b/drivers/mtd/nand/brcmnand/brcmnand.c > @@ -1545,6 +1545,56 @@ static int brcmnand_read_by_pio(struct mtd_info *mtd, struct nand_chip *chip, > return ret; > } > > +/* > + * Check a page to see if it is erased (w/ bitflips) after an uncorrectable ECC > + * error > + * > + * Because the HW ECC signals an ECC error if an erase paged has even a single > + * bitflip, we must check each ECC error to see if it is actually an erased > + * page with bitflips, not a truly corrupted page. > + * > + * On a real error, return a negative error code (-EBADMSG for ECC error), and > + * buf will contain raw data. > + * Otherwise, buf gets filled with 0xffs and return the maximum number of > + * bitflips-per-ECC-sector to the caller. > + * > + */ > +static int brcmstb_nand_verify_erased_page(struct mtd_info *mtd, > + struct nand_chip *chip, void *buf, u64 addr) > +{ > + int i, sas; > + void *oob = chip->oob_poi; > + int bitflips = 0; > + int page = addr >> chip->page_shift; > + int ret; > + > + if (!buf) { > + buf = chip->buffers->databuf; > + /* Invalidate page cache */ > + chip->pagebuf = -1; > + } > + > + sas = mtd->oobsize / chip->ecc.steps; > + > + /* read without ecc for verification */ > + chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page); > + ret = chip->ecc.read_page_raw(mtd, chip, buf, true, page); > + if (ret) > + return ret; > + > + for (i = 0; i < chip->ecc.steps; i++, oob += sas) { > + ret = nand_check_erased_ecc_chunk(buf, chip->ecc.size, > + oob, sas, NULL, 0, > + chip->ecc.strength); > + if (ret < 0) > + return ret; > + > + bitflips = max(bitflips, ret); > + } > + > + return bitflips; > +} > + > static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip, > u64 addr, unsigned int trans, u32 *buf, u8 *oob) > { > @@ -1575,6 +1625,18 @@ static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip, > } > > if (mtd_is_eccerr(err)) { > + /* > + * Controller version 7.2 has hw encoder to detect erased page > + * bitflips, apply sw verification for older controllers only > + */ > + if (ctrl->nand_version < 0x0702) { > + err = brcmstb_nand_verify_erased_page(mtd, chip, buf, > + addr); > + /* erased page bitflips corrected */ > + if (err > 0) > + return err; > + } > + > dev_dbg(ctrl->dev, "uncorrectable error at 0x%llx\n", > (unsigned long long)err_addr); > mtd->ecc_stats.failed++;
diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c index b76ad7c..7ee9617 100644 --- a/drivers/mtd/nand/brcmnand/brcmnand.c +++ b/drivers/mtd/nand/brcmnand/brcmnand.c @@ -1545,6 +1545,56 @@ static int brcmnand_read_by_pio(struct mtd_info *mtd, struct nand_chip *chip, return ret; } +/* + * Check a page to see if it is erased (w/ bitflips) after an uncorrectable ECC + * error + * + * Because the HW ECC signals an ECC error if an erase paged has even a single + * bitflip, we must check each ECC error to see if it is actually an erased + * page with bitflips, not a truly corrupted page. + * + * On a real error, return a negative error code (-EBADMSG for ECC error), and + * buf will contain raw data. + * Otherwise, buf gets filled with 0xffs and return the maximum number of + * bitflips-per-ECC-sector to the caller. + * + */ +static int brcmstb_nand_verify_erased_page(struct mtd_info *mtd, + struct nand_chip *chip, void *buf, u64 addr) +{ + int i, sas; + void *oob = chip->oob_poi; + int bitflips = 0; + int page = addr >> chip->page_shift; + int ret; + + if (!buf) { + buf = chip->buffers->databuf; + /* Invalidate page cache */ + chip->pagebuf = -1; + } + + sas = mtd->oobsize / chip->ecc.steps; + + /* read without ecc for verification */ + chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page); + ret = chip->ecc.read_page_raw(mtd, chip, buf, true, page); + if (ret) + return ret; + + for (i = 0; i < chip->ecc.steps; i++, oob += sas) { + ret = nand_check_erased_ecc_chunk(buf, chip->ecc.size, + oob, sas, NULL, 0, + chip->ecc.strength); + if (ret < 0) + return ret; + + bitflips = max(bitflips, ret); + } + + return bitflips; +} + static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip, u64 addr, unsigned int trans, u32 *buf, u8 *oob) { @@ -1575,6 +1625,18 @@ static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip, } if (mtd_is_eccerr(err)) { + /* + * Controller version 7.2 has hw encoder to detect erased page + * bitflips, apply sw verification for older controllers only + */ + if (ctrl->nand_version < 0x0702) { + err = brcmstb_nand_verify_erased_page(mtd, chip, buf, + addr); + /* erased page bitflips corrected */ + if (err > 0) + return err; + } + dev_dbg(ctrl->dev, "uncorrectable error at 0x%llx\n", (unsigned long long)err_addr); mtd->ecc_stats.failed++;
Check for erased page bitflips in a page. And if well within threshold return data as all 0xff. Apply sw check for controller version < 7.2. Controller vesion >= 7.2 has hw support. Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com> --- V3 changes Return the max bitflips from a sector within a page V2 changes Added use of nand_check_erased_ecc_chunk Restrict change to older controller < 7.2 --- drivers/mtd/nand/brcmnand/brcmnand.c | 62 ++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+)