mtd: nand: use ECC, if present, when scanning OOB (a7e68834) · Commits · 戴 / test

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 <computersforpeace@gmail.com> Signed-off-by:

Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by:

David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/nand_bbt.c

+20 −7

Original line number	Diff line number	Diff line
		@@ -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)
		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,

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