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Commit afc0ea1b authored by Roger Quadros's avatar Roger Quadros Committed by Brian Norris
Browse files

mtd: mtd_oobtest: add bitflip_limit parameter 



It is common for NAND devices to have bitflip errors.
Add a bitflip_limit parameter to specify how many bitflips per
page we can tolerate without flagging an error.
By default zero bitflips are tolerated.

Signed-off-by: default avatarRoger Quadros <rogerq@ti.com>
Signed-off-by: default avatarSekhar Nori <nsekhar@ti.com>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
parent 5a66088b

drivers/mtd/tests/oobtest.c

+47 −18
Original line number Diff line number Diff line
@@ -34,8 +34,11 @@ 
#include "mtd_test.h"



static int dev = -EINVAL;

static int bitflip_limit;

module_param(dev, int, S_IRUGO);

MODULE_PARM_DESC(dev, "MTD device number to use");

module_param(bitflip_limit, int, S_IRUGO);

MODULE_PARM_DESC(bitflip_limit, "Max. allowed bitflips per page");



static struct mtd_info *mtd;

static unsigned char *readbuf;
@@ -115,24 +118,27 @@ static int write_whole_device(void) 
	return 0;

}



/* Display the address, offset and data bytes at comparison failure */

static int memcmpshow(loff_t addr, const void *cs, const void *ct, size_t count)

/*

 * Display the address, offset and data bytes at comparison failure.

 * Return number of bitflips encountered.

 */

static size_t memcmpshow(loff_t addr, const void *cs, const void *ct, size_t count)

{

	const unsigned char *su1, *su2;

	int res;

	int ret = 0;

	size_t i = 0;

	size_t bitflips = 0;



	for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--, i++) {

		res = *su1 ^ *su2;

		if (res) {

			pr_info("error @addr[0x%lx:0x%x] 0x%x -> 0x%x diff 0x%x\n",

				(unsigned long)addr, i, *su1, *su2, res);

			ret = 1;

			bitflips += hweight8(res);

		}

	}



	return ret;

	return bitflips;

}



static int verify_eraseblock(int ebnum)
@@ -141,6 +147,7 @@ static int verify_eraseblock(int ebnum) 
	struct mtd_oob_ops ops;

	int err = 0;

	loff_t addr = (loff_t)ebnum * mtd->erasesize;

	size_t bitflips;



	prandom_bytes_state(&rnd_state, writebuf, use_len_max * pgcnt);

	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
@@ -159,9 +166,11 @@ static int verify_eraseblock(int ebnum) 
			errcnt += 1;

			return err ? err : -1;

		}

		if (memcmpshow(addr, readbuf,



		bitflips = memcmpshow(addr, readbuf,

				      writebuf + (use_len_max * i) + use_offset,

			       use_len)) {

				      use_len);

		if (bitflips > bitflip_limit) {

			pr_err("error: verify failed at %#llx\n",

			       (long long)addr);

			errcnt += 1;
@@ -169,7 +178,10 @@ static int verify_eraseblock(int ebnum) 
				pr_err("error: too many errors\n");

				return -1;

			}

		} else if (bitflips) {

			pr_info("ignoring error as within bitflip_limit\n");

		}



		if (use_offset != 0 || use_len < mtd->ecclayout->oobavail) {

			int k;
@@ -188,9 +200,10 @@ static int verify_eraseblock(int ebnum) 
				errcnt += 1;

				return err ? err : -1;

			}

			if (memcmpshow(addr, readbuf + use_offset,

			bitflips = memcmpshow(addr, readbuf + use_offset,

					      writebuf + (use_len_max * i) + use_offset,

				       use_len)) {

					      use_len);

			if (bitflips > bitflip_limit) {

				pr_err("error: verify failed at %#llx\n",

						(long long)addr);

				errcnt += 1;
@@ -198,7 +211,10 @@ static int verify_eraseblock(int ebnum) 
					pr_err("error: too many errors\n");

					return -1;

				}

			} else if (bitflips) {

				pr_info("ignoring error as within bitflip_limit\n");

			}



			for (k = 0; k < use_offset; ++k)

				if (readbuf[k] != 0xff) {

					pr_err("error: verify 0xff "
@@ -237,6 +253,9 @@ static int verify_eraseblock_in_one_go(int ebnum) 
	int err = 0;

	loff_t addr = (loff_t)ebnum * mtd->erasesize;

	size_t len = mtd->ecclayout->oobavail * pgcnt;

	size_t oobavail = mtd->ecclayout->oobavail;

	size_t bitflips;

	int i;



	prandom_bytes_state(&rnd_state, writebuf, len);

	ops.mode      = MTD_OPS_AUTO_OOB;
@@ -247,6 +266,8 @@ static int verify_eraseblock_in_one_go(int ebnum) 
	ops.ooboffs   = 0;

	ops.datbuf    = NULL;

	ops.oobbuf    = readbuf;



	/* read entire block's OOB at one go */

	err = mtd_read_oob(mtd, addr, &ops);

	if (err || ops.oobretlen != len) {

		pr_err("error: readoob failed at %#llx\n",
@@ -254,7 +275,12 @@ static int verify_eraseblock_in_one_go(int ebnum) 
		errcnt += 1;

		return err ? err : -1;

	}

	if (memcmpshow(addr, readbuf, writebuf, len)) {



	/* verify one page OOB at a time for bitflip per page limit check */

	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {

		bitflips = memcmpshow(addr, readbuf + (i * oobavail),

				      writebuf + (i * oobavail), oobavail);

		if (bitflips > bitflip_limit) {

			pr_err("error: verify failed at %#llx\n",

			       (long long)addr);

			errcnt += 1;
@@ -262,6 +288,9 @@ static int verify_eraseblock_in_one_go(int ebnum) 
				pr_err("error: too many errors\n");

				return -1;

			}

		} else if (bitflips) {

			pr_info("ignoring error as within bitflip_limit\n");

		}

	}



	return err;