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Commit 9a1fcdfd authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

[MTD] NAND Signal that a bitflip was corrected by ECC 



Return -EUCLEAN on read when a bitflip was detected and corrected, so the
clients can react and eventually copy the affected block to a spare one.
Make all in kernel users aware of the change.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 8593fbc6

drivers/mtd/inftlcore.c

+5 −2
Original line number Diff line number Diff line
@@ -355,7 +355,7 @@ static u16 INFTL_foldchain(struct INFTLrecord *inftl, unsigned thisVUC, unsigned 
		ret = mtd->read(mtd, (inftl->EraseSize * BlockMap[block]) +

				(block * SECTORSIZE), SECTORSIZE, &retlen,

				movebuf);

		if (ret < 0) {

		if (ret < 0 && ret != -EUCLEAN) {

			ret = mtd->read(mtd,

					(inftl->EraseSize * BlockMap[block]) +

					(block * SECTORSIZE), SECTORSIZE,
@@ -922,7 +922,10 @@ foundit: 
	} else {

		size_t retlen;

		loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;

		if (mtd->read(mtd, ptr, SECTORSIZE, &retlen, buffer))

		int ret = mtd->read(mtd, ptr, SECTORSIZE, &retlen, buffer);



		/* Handle corrected bit flips gracefully */

		if (ret < 0 && ret != -EUCLEAN)

			return -EIO;

	}

	return 0;

drivers/mtd/mtdchar.c

+4 −1
Original line number Diff line number Diff line
@@ -199,10 +199,13 @@ static ssize_t mtd_read(struct file *file, char __user *buf, size_t count,loff_t 
		/* Nand returns -EBADMSG on ecc errors, but it returns

		 * the data. For our userspace tools it is important

		 * to dump areas with ecc errors !

		 * For kernel internal usage it also might return -EUCLEAN

		 * to signal the caller that a bitflip has occured and has

		 * been corrected by the ECC algorithm.

		 * Userspace software which accesses NAND this way

		 * must be aware of the fact that it deals with NAND

		 */

		if (!ret || (ret == -EBADMSG)) {

		if (!ret || (ret == -EUCLEAN) || (ret == -EBADMSG)) {

			*ppos += retlen;

			if (copy_to_user(buf, kbuf, retlen)) {

				kfree(kbuf);

drivers/mtd/mtdconcat.c

+12 −3
Original line number Diff line number Diff line
@@ -56,7 +56,7 @@ concat_read(struct mtd_info *mtd, loff_t from, size_t len, 
	    size_t * retlen, u_char * buf)

{

	struct mtd_concat *concat = CONCAT(mtd);

	int err = -EINVAL;

	int ret = 0, err = -EINVAL;

	int i;



	*retlen = 0;
@@ -80,9 +80,18 @@ concat_read(struct mtd_info *mtd, loff_t from, size_t len, 


		err = subdev->read(subdev, from, size, &retsize, buf);



		if (err)

		if (err && (err != -EBADMSG) && (err != -EUCLEAN))

			break;



		/* Save information about bitflips! */

		if (err) {

			if (err == -EBADMSG)

				ret = err;

			else if (!ret)

				ret = err;

			err = 0;

		}



		*retlen += retsize;

		len -= size;

		if (len == 0)
@@ -92,7 +101,7 @@ concat_read(struct mtd_info *mtd, loff_t from, size_t len, 
		buf += size;

		from = 0;

	}

	return err;

	return err ? err : ret;

}



static int

drivers/mtd/nand/nand_base.c

+4 −1
Original line number Diff line number Diff line
@@ -1035,7 +1035,10 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from, 
	if (ret)

		return ret;



	return mtd->ecc_stats.failed - stats.failed ? -EBADMSG : 0;

	if (mtd->ecc_stats.failed - stats.failed)

		return -EBADMSG;



	return  mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;

}



/**

drivers/mtd/nftlcore.c

+4 −2
Original line number Diff line number Diff line
@@ -422,7 +422,7 @@ static u16 NFTL_foldchain (struct NFTLrecord *nftl, unsigned thisVUC, unsigned p 


		ret = mtd->read(mtd, (nftl->EraseSize * BlockMap[block]) + (block * 512),

				512, &retlen, movebuf);

		if (ret < 0) {

		if (ret < 0 && ret != -EUCLEAN) {

			ret = mtd->read(mtd, (nftl->EraseSize * BlockMap[block])

					+ (block * 512), 512, &retlen,

					movebuf);
@@ -768,7 +768,9 @@ static int nftl_readblock(struct mtd_blktrans_dev *mbd, unsigned long block, 
	} else {

		loff_t ptr = (lastgoodEUN * nftl->EraseSize) + blockofs;

		size_t retlen;

		if (mtd->read(mtd, ptr, 512, &retlen, buffer))

		int res = mtd->read(mtd, ptr, 512, &retlen, buffer);



		if (res < 0 && res != -EUCLEAN)

			return -EIO;

	}

	return 0;