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Commit a7e68834 authored by Brian Norris's avatar Brian Norris Committed by David Woodhouse
Browse files

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: default avatarBrian Norris <computersforpeace@gmail.com>
Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 491ed06f

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,