From: Brian Norris Date: Fri, 22 Jun 2012 23:35:45 +0000 (-0700) Subject: mtd: nand: use ECC, if present, when scanning OOB X-Git-Tag: firefly_0821_release~3680^2~1874^2~104 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a7e68834fc273930c17e3decaddc13acb87a7dce;p=firefly-linux-kernel-4.4.55.git mtd: nand: use ECC, if present, when scanning OOB scan_read_raw_oob() is used in only in places where the MTD_OPS_PLACE_OOB mode is preferable to MTD_OPS_RAW mode, so use MTD_OPS_PLACE_OOB instead. MTD_OPS_PLACE_OOB provides the same functionality with the potential[1] added bonus of error correction. This brings scan_block_full() in line with scan_block_fast() so that they both read bad block markers with MTD_OPS_PLACE_OOB. This can help in preventing 0xff markers (in good blocks) from being interpreted as bad block indicators in the presence of a single bitflip. Note that ECC error codes (EUCLEAN or EBADMSG) are already silently ignored in all users of scan_read_raw_oob(). [1] Few drivers perform proper error correction on OOB data. In those cases, the use of MTD_OPS_RAW vs. MTD_OPS_PLACE_OOB is not significant. Signed-off-by: Brian Norris Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse --- diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c index f5839f06cece..0e928f3efaa4 100644 --- a/drivers/mtd/nand/nand_bbt.c +++ b/drivers/mtd/nand/nand_bbt.c @@ -289,14 +289,24 @@ static int scan_read_raw_data(struct mtd_info *mtd, uint8_t *buf, loff_t offs, return mtd_read(mtd, offs, len, &retlen, buf); } -/* Scan read raw data from flash */ +/** + * scan_read_raw_oob - [GENERIC] Scan data+OOB region to buffer + * @mtd: MTD device structure + * @buf: temporary buffer + * @offs: offset at which to scan + * @len: length of data region to read + * + * Scan read data from data+OOB. May traverse multiple pages, interleaving + * page,OOB,page,OOB,... in buf. Completes transfer and returns the "strongest" + * ECC condition (error or bitflip). May quit on the first (non-ECC) error. + */ static int scan_read_raw_oob(struct mtd_info *mtd, uint8_t *buf, loff_t offs, size_t len) { struct mtd_oob_ops ops; - int res; + int res, ret = 0; - ops.mode = MTD_OPS_RAW; + ops.mode = MTD_OPS_PLACE_OOB; ops.ooboffs = 0; ops.ooblen = mtd->oobsize; @@ -306,15 +316,18 @@ static int scan_read_raw_oob(struct mtd_info *mtd, uint8_t *buf, loff_t offs, ops.oobbuf = buf + ops.len; res = mtd_read_oob(mtd, offs, &ops); - - if (res) - return res; + if (res) { + if (!mtd_is_bitflip_or_eccerr(res)) + return res; + else if (mtd_is_eccerr(res) || !ret) + ret = res; + } buf += mtd->oobsize + mtd->writesize; len -= mtd->writesize; offs += mtd->writesize; } - return 0; + return ret; } static int scan_read_raw(struct mtd_info *mtd, uint8_t *buf, loff_t offs,