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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: Roger Quadros <rogerq@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
This commit is contained in:
Roger Quadros 2014-10-21 16:53:28 +03:00 committed by Brian Norris
parent 5a66088bff
commit afc0ea1b8e
1 changed files with 47 additions and 18 deletions
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65
drivers/mtd/tests/oobtest.c
View File

@ -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,
writebuf + (use_len_max * i) + use_offset,
use_len)) {
bitflips = memcmpshow(addr, readbuf,
writebuf + (use_len_max * i) + use_offset,
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,
writebuf + (use_len_max * i) + use_offset,
use_len)) {
bitflips = memcmpshow(addr, readbuf + use_offset,
writebuf + (use_len_max * i) + use_offset,
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",
@ -254,13 +275,21 @@ static int verify_eraseblock_in_one_go(int ebnum)
errcnt += 1;
return err ? err : -1;
}
if (memcmpshow(addr, readbuf, writebuf, len)) {
pr_err("error: verify failed at %#llx\n",
(long long)addr);
errcnt += 1;
if (errcnt > 1000) {
pr_err("error: too many errors\n");
return -1;
/* 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;
if (errcnt > 1000) {
pr_err("error: too many errors\n");
return -1;
}
} else if (bitflips) {
pr_info("ignoring error as within bitflip_limit\n");
}
}