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author | Wan, Jane (Nokia - US/Sunnyvale) <jane.wan@nokia.com> | 2018-05-13 04:30:02 +0000 |
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committer | Boris Brezillon <boris.brezillon@bootlin.com> | 2018-05-13 09:50:16 +0200 |
commit | 39138c1f4a31f3468fa2e44aba4495c0c30da205 (patch) | |
tree | 66ff67df4e0bc9df7f2bb6cb87c354f08d5d880b | |
parent | a676688032e819c4bb1999a422553a1a1f52ce45 (diff) | |
download | op-kernel-dev-39138c1f4a31f3468fa2e44aba4495c0c30da205.zip op-kernel-dev-39138c1f4a31f3468fa2e44aba4495c0c30da205.tar.gz |
mtd: rawnand: use bit-wise majority to recover the ONFI param page
Per ONFI specification (Rev. 4.0), if all parameter pages have invalid
CRC values, the bit-wise majority may be used to recover the contents
of the parameter page from the parameter page copies present.
Signed-off-by: Jane Wan <Jane.Wan@nokia.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
-rw-r--r-- | drivers/mtd/nand/raw/nand_base.c | 52 |
1 files changed, 47 insertions, 5 deletions
diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c index 414a2a3..faf10c8 100644 --- a/drivers/mtd/nand/raw/nand_base.c +++ b/drivers/mtd/nand/raw/nand_base.c @@ -5087,6 +5087,37 @@ ext_out: } /* + * Recover data with bit-wise majority + */ +static void nand_bit_wise_majority(const void **srcbufs, + unsigned int nsrcbufs, + void *dstbuf, + unsigned int bufsize) +{ + int i, j, k; + + for (i = 0; i < bufsize; i++) { + u8 val = 0; + + for (j = 0; j < 8; j++) { + unsigned int cnt = 0; + + for (k = 0; k < nsrcbufs; k++) { + const u8 *srcbuf = srcbufs[k]; + + if (srcbuf[i] & BIT(j)) + cnt++; + } + + if (cnt > nsrcbufs / 2) + val |= BIT(j); + } + + ((u8 *)dstbuf)[i] = val; + } +} + +/* * Check if the NAND chip is ONFI compliant, returns 1 if it is, 0 otherwise. */ static int nand_flash_detect_onfi(struct nand_chip *chip) @@ -5102,7 +5133,7 @@ static int nand_flash_detect_onfi(struct nand_chip *chip) return 0; /* ONFI chip: allocate a buffer to hold its parameter page */ - p = kzalloc(sizeof(*p), GFP_KERNEL); + p = kzalloc((sizeof(*p) * 3), GFP_KERNEL); if (!p) return -ENOMEM; @@ -5113,21 +5144,32 @@ static int nand_flash_detect_onfi(struct nand_chip *chip) } for (i = 0; i < 3; i++) { - ret = nand_read_data_op(chip, p, sizeof(*p), true); + ret = nand_read_data_op(chip, &p[i], sizeof(*p), true); if (ret) { ret = 0; goto free_onfi_param_page; } - if (onfi_crc16(ONFI_CRC_BASE, (uint8_t *)p, 254) == + if (onfi_crc16(ONFI_CRC_BASE, (u8 *)&p[i], 254) == le16_to_cpu(p->crc)) { + if (i) + memcpy(p, &p[i], sizeof(*p)); break; } } if (i == 3) { - pr_err("Could not find valid ONFI parameter page; aborting\n"); - goto free_onfi_param_page; + const void *srcbufs[3] = {p, p + 1, p + 2}; + + pr_warn("Could not find a valid ONFI parameter page, trying bit-wise majority to recover it\n"); + nand_bit_wise_majority(srcbufs, ARRAY_SIZE(srcbufs), p, + sizeof(*p)); + + if (onfi_crc16(ONFI_CRC_BASE, (u8 *)p, 254) != + le16_to_cpu(p->crc)) { + pr_err("ONFI parameter recovery failed, aborting\n"); + goto free_onfi_param_page; + } } /* Check version */ |