diff options
author | Kamal Dasu <kdasu.kdev@gmail.com> | 2016-06-09 21:17:54 (GMT) |
---|---|---|
committer | Boris Brezillon <boris.brezillon@free-electrons.com> | 2016-06-13 15:03:23 (GMT) |
commit | 02b88eea9f9cab82f5f4be234c64466503021f82 (patch) | |
tree | b1e1f53c7a6d1605c19cd713079fb898e513a200 /drivers/mtd/nand | |
parent | 1c7fe6b438433e16d5b1211380c305351ac38299 (diff) | |
download | linux-02b88eea9f9cab82f5f4be234c64466503021f82.tar.xz |
mtd: brcmnand: Add check for erased page bitflips
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>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Diffstat (limited to 'drivers/mtd/nand')
-rw-r--r-- | drivers/mtd/nand/brcmnand/brcmnand.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c index 0a54a0f..f0b0672 100644 --- a/drivers/mtd/nand/brcmnand/brcmnand.c +++ b/drivers/mtd/nand/brcmnand/brcmnand.c @@ -1602,6 +1602,56 @@ 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) { @@ -1632,6 +1682,18 @@ 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++; |