xref: /openbmc/linux/drivers/mtd/tests/oobtest.c (revision 015d239a)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2006-2008 Nokia Corporation
4  *
5  * Test OOB read and write on MTD device.
6  *
7  * Author: Adrian Hunter <ext-adrian.hunter@nokia.com>
8  */
9 
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11 
12 #include <asm/div64.h>
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/moduleparam.h>
16 #include <linux/err.h>
17 #include <linux/mtd/mtd.h>
18 #include <linux/slab.h>
19 #include <linux/sched.h>
20 #include <linux/random.h>
21 
22 #include "mtd_test.h"
23 
24 static int dev = -EINVAL;
25 static int bitflip_limit;
26 module_param(dev, int, S_IRUGO);
27 MODULE_PARM_DESC(dev, "MTD device number to use");
28 module_param(bitflip_limit, int, S_IRUGO);
29 MODULE_PARM_DESC(bitflip_limit, "Max. allowed bitflips per page");
30 
31 static struct mtd_info *mtd;
32 static unsigned char *readbuf;
33 static unsigned char *writebuf;
34 static unsigned char *bbt;
35 
36 static int ebcnt;
37 static int pgcnt;
38 static int errcnt;
39 static int use_offset;
40 static int use_len;
41 static int use_len_max;
42 static int vary_offset;
43 static struct rnd_state rnd_state;
44 
45 static void do_vary_offset(void)
46 {
47 	use_len -= 1;
48 	if (use_len < 1) {
49 		use_offset += 1;
50 		if (use_offset >= use_len_max)
51 			use_offset = 0;
52 		use_len = use_len_max - use_offset;
53 	}
54 }
55 
56 static int write_eraseblock(int ebnum)
57 {
58 	int i;
59 	struct mtd_oob_ops ops;
60 	int err = 0;
61 	loff_t addr = (loff_t)ebnum * mtd->erasesize;
62 
63 	prandom_bytes_state(&rnd_state, writebuf, use_len_max * pgcnt);
64 	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
65 		ops.mode      = MTD_OPS_AUTO_OOB;
66 		ops.len       = 0;
67 		ops.retlen    = 0;
68 		ops.ooblen    = use_len;
69 		ops.oobretlen = 0;
70 		ops.ooboffs   = use_offset;
71 		ops.datbuf    = NULL;
72 		ops.oobbuf    = writebuf + (use_len_max * i) + use_offset;
73 		err = mtd_write_oob(mtd, addr, &ops);
74 		if (err || ops.oobretlen != use_len) {
75 			pr_err("error: writeoob failed at %#llx\n",
76 			       (long long)addr);
77 			pr_err("error: use_len %d, use_offset %d\n",
78 			       use_len, use_offset);
79 			errcnt += 1;
80 			return err ? err : -1;
81 		}
82 		if (vary_offset)
83 			do_vary_offset();
84 	}
85 
86 	return err;
87 }
88 
89 static int write_whole_device(void)
90 {
91 	int err;
92 	unsigned int i;
93 
94 	pr_info("writing OOBs of whole device\n");
95 	for (i = 0; i < ebcnt; ++i) {
96 		if (bbt[i])
97 			continue;
98 		err = write_eraseblock(i);
99 		if (err)
100 			return err;
101 		if (i % 256 == 0)
102 			pr_info("written up to eraseblock %u\n", i);
103 
104 		err = mtdtest_relax();
105 		if (err)
106 			return err;
107 	}
108 	pr_info("written %u eraseblocks\n", i);
109 	return 0;
110 }
111 
112 /*
113  * Display the address, offset and data bytes at comparison failure.
114  * Return number of bitflips encountered.
115  */
116 static size_t memcmpshowoffset(loff_t addr, loff_t offset, const void *cs,
117 			       const void *ct, size_t count)
118 {
119 	const unsigned char *su1, *su2;
120 	int res;
121 	size_t i = 0;
122 	size_t bitflips = 0;
123 
124 	for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--, i++) {
125 		res = *su1 ^ *su2;
126 		if (res) {
127 			pr_info("error @addr[0x%lx:0x%lx] 0x%x -> 0x%x diff 0x%x\n",
128 				(unsigned long)addr, (unsigned long)offset + i,
129 				*su1, *su2, res);
130 			bitflips += hweight8(res);
131 		}
132 	}
133 
134 	return bitflips;
135 }
136 
137 #define memcmpshow(addr, cs, ct, count) memcmpshowoffset((addr), 0, (cs), (ct),\
138 							 (count))
139 
140 /*
141  * Compare with 0xff and show the address, offset and data bytes at
142  * comparison failure. Return number of bitflips encountered.
143  */
144 static size_t memffshow(loff_t addr, loff_t offset, const void *cs,
145 			size_t count)
146 {
147 	const unsigned char *su1;
148 	int res;
149 	size_t i = 0;
150 	size_t bitflips = 0;
151 
152 	for (su1 = cs; 0 < count; ++su1, count--, i++) {
153 		res = *su1 ^ 0xff;
154 		if (res) {
155 			pr_info("error @addr[0x%lx:0x%lx] 0x%x -> 0xff diff 0x%x\n",
156 				(unsigned long)addr, (unsigned long)offset + i,
157 				*su1, res);
158 			bitflips += hweight8(res);
159 		}
160 	}
161 
162 	return bitflips;
163 }
164 
165 static int verify_eraseblock(int ebnum)
166 {
167 	int i;
168 	struct mtd_oob_ops ops;
169 	int err = 0;
170 	loff_t addr = (loff_t)ebnum * mtd->erasesize;
171 	size_t bitflips;
172 
173 	prandom_bytes_state(&rnd_state, writebuf, use_len_max * pgcnt);
174 	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
175 		ops.mode      = MTD_OPS_AUTO_OOB;
176 		ops.len       = 0;
177 		ops.retlen    = 0;
178 		ops.ooblen    = use_len;
179 		ops.oobretlen = 0;
180 		ops.ooboffs   = use_offset;
181 		ops.datbuf    = NULL;
182 		ops.oobbuf    = readbuf;
183 		err = mtd_read_oob(mtd, addr, &ops);
184 		if (mtd_is_bitflip(err))
185 			err = 0;
186 
187 		if (err || ops.oobretlen != use_len) {
188 			pr_err("error: readoob failed at %#llx\n",
189 			       (long long)addr);
190 			errcnt += 1;
191 			return err ? err : -1;
192 		}
193 
194 		bitflips = memcmpshow(addr, readbuf,
195 				      writebuf + (use_len_max * i) + use_offset,
196 				      use_len);
197 		if (bitflips > bitflip_limit) {
198 			pr_err("error: verify failed at %#llx\n",
199 			       (long long)addr);
200 			errcnt += 1;
201 			if (errcnt > 1000) {
202 				pr_err("error: too many errors\n");
203 				return -1;
204 			}
205 		} else if (bitflips) {
206 			pr_info("ignoring error as within bitflip_limit\n");
207 		}
208 
209 		if (use_offset != 0 || use_len < mtd->oobavail) {
210 			int k;
211 
212 			ops.mode      = MTD_OPS_AUTO_OOB;
213 			ops.len       = 0;
214 			ops.retlen    = 0;
215 			ops.ooblen    = mtd->oobavail;
216 			ops.oobretlen = 0;
217 			ops.ooboffs   = 0;
218 			ops.datbuf    = NULL;
219 			ops.oobbuf    = readbuf;
220 			err = mtd_read_oob(mtd, addr, &ops);
221 			if (mtd_is_bitflip(err))
222 				err = 0;
223 
224 			if (err || ops.oobretlen != mtd->oobavail) {
225 				pr_err("error: readoob failed at %#llx\n",
226 						(long long)addr);
227 				errcnt += 1;
228 				return err ? err : -1;
229 			}
230 			bitflips = memcmpshowoffset(addr, use_offset,
231 						    readbuf + use_offset,
232 						    writebuf + (use_len_max * i) + use_offset,
233 						    use_len);
234 
235 			/* verify pre-offset area for 0xff */
236 			bitflips += memffshow(addr, 0, readbuf, use_offset);
237 
238 			/* verify post-(use_offset + use_len) area for 0xff */
239 			k = use_offset + use_len;
240 			bitflips += memffshow(addr, k, readbuf + k,
241 					      mtd->oobavail - k);
242 
243 			if (bitflips > bitflip_limit) {
244 				pr_err("error: verify failed at %#llx\n",
245 						(long long)addr);
246 				errcnt += 1;
247 				if (errcnt > 1000) {
248 					pr_err("error: too many errors\n");
249 					return -1;
250 				}
251 			} else if (bitflips) {
252 				pr_info("ignoring errors as within bitflip limit\n");
253 			}
254 		}
255 		if (vary_offset)
256 			do_vary_offset();
257 	}
258 	return err;
259 }
260 
261 static int verify_eraseblock_in_one_go(int ebnum)
262 {
263 	struct mtd_oob_ops ops;
264 	int err = 0;
265 	loff_t addr = (loff_t)ebnum * mtd->erasesize;
266 	size_t len = mtd->oobavail * pgcnt;
267 	size_t oobavail = mtd->oobavail;
268 	size_t bitflips;
269 	int i;
270 
271 	prandom_bytes_state(&rnd_state, writebuf, len);
272 	ops.mode      = MTD_OPS_AUTO_OOB;
273 	ops.len       = 0;
274 	ops.retlen    = 0;
275 	ops.ooblen    = len;
276 	ops.oobretlen = 0;
277 	ops.ooboffs   = 0;
278 	ops.datbuf    = NULL;
279 	ops.oobbuf    = readbuf;
280 
281 	/* read entire block's OOB at one go */
282 	err = mtd_read_oob(mtd, addr, &ops);
283 	if (mtd_is_bitflip(err))
284 		err = 0;
285 
286 	if (err || ops.oobretlen != len) {
287 		pr_err("error: readoob failed at %#llx\n",
288 		       (long long)addr);
289 		errcnt += 1;
290 		return err ? err : -1;
291 	}
292 
293 	/* verify one page OOB at a time for bitflip per page limit check */
294 	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
295 		bitflips = memcmpshow(addr, readbuf + (i * oobavail),
296 				      writebuf + (i * oobavail), oobavail);
297 		if (bitflips > bitflip_limit) {
298 			pr_err("error: verify failed at %#llx\n",
299 			       (long long)addr);
300 			errcnt += 1;
301 			if (errcnt > 1000) {
302 				pr_err("error: too many errors\n");
303 				return -1;
304 			}
305 		} else if (bitflips) {
306 			pr_info("ignoring error as within bitflip_limit\n");
307 		}
308 	}
309 
310 	return err;
311 }
312 
313 static int verify_all_eraseblocks(void)
314 {
315 	int err;
316 	unsigned int i;
317 
318 	pr_info("verifying all eraseblocks\n");
319 	for (i = 0; i < ebcnt; ++i) {
320 		if (bbt[i])
321 			continue;
322 		err = verify_eraseblock(i);
323 		if (err)
324 			return err;
325 		if (i % 256 == 0)
326 			pr_info("verified up to eraseblock %u\n", i);
327 
328 		err = mtdtest_relax();
329 		if (err)
330 			return err;
331 	}
332 	pr_info("verified %u eraseblocks\n", i);
333 	return 0;
334 }
335 
336 static int __init mtd_oobtest_init(void)
337 {
338 	int err = 0;
339 	unsigned int i;
340 	uint64_t tmp;
341 	struct mtd_oob_ops ops;
342 	loff_t addr = 0, addr0;
343 
344 	printk(KERN_INFO "\n");
345 	printk(KERN_INFO "=================================================\n");
346 
347 	if (dev < 0) {
348 		pr_info("Please specify a valid mtd-device via module parameter\n");
349 		pr_crit("CAREFUL: This test wipes all data on the specified MTD device!\n");
350 		return -EINVAL;
351 	}
352 
353 	pr_info("MTD device: %d\n", dev);
354 
355 	mtd = get_mtd_device(NULL, dev);
356 	if (IS_ERR(mtd)) {
357 		err = PTR_ERR(mtd);
358 		pr_err("error: cannot get MTD device\n");
359 		return err;
360 	}
361 
362 	if (!mtd_type_is_nand(mtd)) {
363 		pr_info("this test requires NAND flash\n");
364 		goto out;
365 	}
366 
367 	tmp = mtd->size;
368 	do_div(tmp, mtd->erasesize);
369 	ebcnt = tmp;
370 	pgcnt = mtd->erasesize / mtd->writesize;
371 
372 	pr_info("MTD device size %llu, eraseblock size %u, "
373 	       "page size %u, count of eraseblocks %u, pages per "
374 	       "eraseblock %u, OOB size %u\n",
375 	       (unsigned long long)mtd->size, mtd->erasesize,
376 	       mtd->writesize, ebcnt, pgcnt, mtd->oobsize);
377 
378 	err = -ENOMEM;
379 	readbuf = kmalloc(mtd->erasesize, GFP_KERNEL);
380 	if (!readbuf)
381 		goto out;
382 	writebuf = kmalloc(mtd->erasesize, GFP_KERNEL);
383 	if (!writebuf)
384 		goto out;
385 	bbt = kzalloc(ebcnt, GFP_KERNEL);
386 	if (!bbt)
387 		goto out;
388 
389 	err = mtdtest_scan_for_bad_eraseblocks(mtd, bbt, 0, ebcnt);
390 	if (err)
391 		goto out;
392 
393 	use_offset = 0;
394 	use_len = mtd->oobavail;
395 	use_len_max = mtd->oobavail;
396 	vary_offset = 0;
397 
398 	/* First test: write all OOB, read it back and verify */
399 	pr_info("test 1 of 5\n");
400 
401 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
402 	if (err)
403 		goto out;
404 
405 	prandom_seed_state(&rnd_state, 1);
406 	err = write_whole_device();
407 	if (err)
408 		goto out;
409 
410 	prandom_seed_state(&rnd_state, 1);
411 	err = verify_all_eraseblocks();
412 	if (err)
413 		goto out;
414 
415 	/*
416 	 * Second test: write all OOB, a block at a time, read it back and
417 	 * verify.
418 	 */
419 	pr_info("test 2 of 5\n");
420 
421 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
422 	if (err)
423 		goto out;
424 
425 	prandom_seed_state(&rnd_state, 3);
426 	err = write_whole_device();
427 	if (err)
428 		goto out;
429 
430 	/* Check all eraseblocks */
431 	prandom_seed_state(&rnd_state, 3);
432 	pr_info("verifying all eraseblocks\n");
433 	for (i = 0; i < ebcnt; ++i) {
434 		if (bbt[i])
435 			continue;
436 		err = verify_eraseblock_in_one_go(i);
437 		if (err)
438 			goto out;
439 		if (i % 256 == 0)
440 			pr_info("verified up to eraseblock %u\n", i);
441 
442 		err = mtdtest_relax();
443 		if (err)
444 			goto out;
445 	}
446 	pr_info("verified %u eraseblocks\n", i);
447 
448 	/*
449 	 * Third test: write OOB at varying offsets and lengths, read it back
450 	 * and verify.
451 	 */
452 	pr_info("test 3 of 5\n");
453 
454 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
455 	if (err)
456 		goto out;
457 
458 	/* Write all eraseblocks */
459 	use_offset = 0;
460 	use_len = mtd->oobavail;
461 	use_len_max = mtd->oobavail;
462 	vary_offset = 1;
463 	prandom_seed_state(&rnd_state, 5);
464 
465 	err = write_whole_device();
466 	if (err)
467 		goto out;
468 
469 	/* Check all eraseblocks */
470 	use_offset = 0;
471 	use_len = mtd->oobavail;
472 	use_len_max = mtd->oobavail;
473 	vary_offset = 1;
474 	prandom_seed_state(&rnd_state, 5);
475 	err = verify_all_eraseblocks();
476 	if (err)
477 		goto out;
478 
479 	use_offset = 0;
480 	use_len = mtd->oobavail;
481 	use_len_max = mtd->oobavail;
482 	vary_offset = 0;
483 
484 	/* Fourth test: try to write off end of device */
485 	pr_info("test 4 of 5\n");
486 
487 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
488 	if (err)
489 		goto out;
490 
491 	addr0 = 0;
492 	for (i = 0; i < ebcnt && bbt[i]; ++i)
493 		addr0 += mtd->erasesize;
494 
495 	/* Attempt to write off end of OOB */
496 	ops.mode      = MTD_OPS_AUTO_OOB;
497 	ops.len       = 0;
498 	ops.retlen    = 0;
499 	ops.ooblen    = 1;
500 	ops.oobretlen = 0;
501 	ops.ooboffs   = mtd->oobavail;
502 	ops.datbuf    = NULL;
503 	ops.oobbuf    = writebuf;
504 	pr_info("attempting to start write past end of OOB\n");
505 	pr_info("an error is expected...\n");
506 	err = mtd_write_oob(mtd, addr0, &ops);
507 	if (err) {
508 		pr_info("error occurred as expected\n");
509 		err = 0;
510 	} else {
511 		pr_err("error: can write past end of OOB\n");
512 		errcnt += 1;
513 	}
514 
515 	/* Attempt to read off end of OOB */
516 	ops.mode      = MTD_OPS_AUTO_OOB;
517 	ops.len       = 0;
518 	ops.retlen    = 0;
519 	ops.ooblen    = 1;
520 	ops.oobretlen = 0;
521 	ops.ooboffs   = mtd->oobavail;
522 	ops.datbuf    = NULL;
523 	ops.oobbuf    = readbuf;
524 	pr_info("attempting to start read past end of OOB\n");
525 	pr_info("an error is expected...\n");
526 	err = mtd_read_oob(mtd, addr0, &ops);
527 	if (mtd_is_bitflip(err))
528 		err = 0;
529 
530 	if (err) {
531 		pr_info("error occurred as expected\n");
532 		err = 0;
533 	} else {
534 		pr_err("error: can read past end of OOB\n");
535 		errcnt += 1;
536 	}
537 
538 	if (bbt[ebcnt - 1])
539 		pr_info("skipping end of device tests because last "
540 		       "block is bad\n");
541 	else {
542 		/* Attempt to write off end of device */
543 		ops.mode      = MTD_OPS_AUTO_OOB;
544 		ops.len       = 0;
545 		ops.retlen    = 0;
546 		ops.ooblen    = mtd->oobavail + 1;
547 		ops.oobretlen = 0;
548 		ops.ooboffs   = 0;
549 		ops.datbuf    = NULL;
550 		ops.oobbuf    = writebuf;
551 		pr_info("attempting to write past end of device\n");
552 		pr_info("an error is expected...\n");
553 		err = mtd_write_oob(mtd, mtd->size - mtd->writesize, &ops);
554 		if (err) {
555 			pr_info("error occurred as expected\n");
556 			err = 0;
557 		} else {
558 			pr_err("error: wrote past end of device\n");
559 			errcnt += 1;
560 		}
561 
562 		/* Attempt to read off end of device */
563 		ops.mode      = MTD_OPS_AUTO_OOB;
564 		ops.len       = 0;
565 		ops.retlen    = 0;
566 		ops.ooblen    = mtd->oobavail + 1;
567 		ops.oobretlen = 0;
568 		ops.ooboffs   = 0;
569 		ops.datbuf    = NULL;
570 		ops.oobbuf    = readbuf;
571 		pr_info("attempting to read past end of device\n");
572 		pr_info("an error is expected...\n");
573 		err = mtd_read_oob(mtd, mtd->size - mtd->writesize, &ops);
574 		if (mtd_is_bitflip(err))
575 			err = 0;
576 
577 		if (err) {
578 			pr_info("error occurred as expected\n");
579 			err = 0;
580 		} else {
581 			pr_err("error: read past end of device\n");
582 			errcnt += 1;
583 		}
584 
585 		err = mtdtest_erase_eraseblock(mtd, ebcnt - 1);
586 		if (err)
587 			goto out;
588 
589 		/* Attempt to write off end of device */
590 		ops.mode      = MTD_OPS_AUTO_OOB;
591 		ops.len       = 0;
592 		ops.retlen    = 0;
593 		ops.ooblen    = mtd->oobavail;
594 		ops.oobretlen = 0;
595 		ops.ooboffs   = 1;
596 		ops.datbuf    = NULL;
597 		ops.oobbuf    = writebuf;
598 		pr_info("attempting to write past end of device\n");
599 		pr_info("an error is expected...\n");
600 		err = mtd_write_oob(mtd, mtd->size - mtd->writesize, &ops);
601 		if (err) {
602 			pr_info("error occurred as expected\n");
603 			err = 0;
604 		} else {
605 			pr_err("error: wrote past end of device\n");
606 			errcnt += 1;
607 		}
608 
609 		/* Attempt to read off end of device */
610 		ops.mode      = MTD_OPS_AUTO_OOB;
611 		ops.len       = 0;
612 		ops.retlen    = 0;
613 		ops.ooblen    = mtd->oobavail;
614 		ops.oobretlen = 0;
615 		ops.ooboffs   = 1;
616 		ops.datbuf    = NULL;
617 		ops.oobbuf    = readbuf;
618 		pr_info("attempting to read past end of device\n");
619 		pr_info("an error is expected...\n");
620 		err = mtd_read_oob(mtd, mtd->size - mtd->writesize, &ops);
621 		if (mtd_is_bitflip(err))
622 			err = 0;
623 
624 		if (err) {
625 			pr_info("error occurred as expected\n");
626 			err = 0;
627 		} else {
628 			pr_err("error: read past end of device\n");
629 			errcnt += 1;
630 		}
631 	}
632 
633 	/* Fifth test: write / read across block boundaries */
634 	pr_info("test 5 of 5\n");
635 
636 	/* Erase all eraseblocks */
637 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
638 	if (err)
639 		goto out;
640 
641 	/* Write all eraseblocks */
642 	prandom_seed_state(&rnd_state, 11);
643 	pr_info("writing OOBs of whole device\n");
644 	for (i = 0; i < ebcnt - 1; ++i) {
645 		int cnt = 2;
646 		int pg;
647 		size_t sz = mtd->oobavail;
648 		if (bbt[i] || bbt[i + 1])
649 			continue;
650 		addr = (loff_t)(i + 1) * mtd->erasesize - mtd->writesize;
651 		prandom_bytes_state(&rnd_state, writebuf, sz * cnt);
652 		for (pg = 0; pg < cnt; ++pg) {
653 			ops.mode      = MTD_OPS_AUTO_OOB;
654 			ops.len       = 0;
655 			ops.retlen    = 0;
656 			ops.ooblen    = sz;
657 			ops.oobretlen = 0;
658 			ops.ooboffs   = 0;
659 			ops.datbuf    = NULL;
660 			ops.oobbuf    = writebuf + pg * sz;
661 			err = mtd_write_oob(mtd, addr, &ops);
662 			if (err)
663 				goto out;
664 			if (i % 256 == 0)
665 				pr_info("written up to eraseblock %u\n", i);
666 
667 			err = mtdtest_relax();
668 			if (err)
669 				goto out;
670 
671 			addr += mtd->writesize;
672 		}
673 	}
674 	pr_info("written %u eraseblocks\n", i);
675 
676 	/* Check all eraseblocks */
677 	prandom_seed_state(&rnd_state, 11);
678 	pr_info("verifying all eraseblocks\n");
679 	for (i = 0; i < ebcnt - 1; ++i) {
680 		if (bbt[i] || bbt[i + 1])
681 			continue;
682 		prandom_bytes_state(&rnd_state, writebuf, mtd->oobavail * 2);
683 		addr = (loff_t)(i + 1) * mtd->erasesize - mtd->writesize;
684 		ops.mode      = MTD_OPS_AUTO_OOB;
685 		ops.len       = 0;
686 		ops.retlen    = 0;
687 		ops.ooblen    = mtd->oobavail * 2;
688 		ops.oobretlen = 0;
689 		ops.ooboffs   = 0;
690 		ops.datbuf    = NULL;
691 		ops.oobbuf    = readbuf;
692 		err = mtd_read_oob(mtd, addr, &ops);
693 		if (mtd_is_bitflip(err))
694 			err = 0;
695 
696 		if (err)
697 			goto out;
698 		if (memcmpshow(addr, readbuf, writebuf,
699 			       mtd->oobavail * 2)) {
700 			pr_err("error: verify failed at %#llx\n",
701 			       (long long)addr);
702 			errcnt += 1;
703 			if (errcnt > 1000) {
704 				pr_err("error: too many errors\n");
705 				goto out;
706 			}
707 		}
708 		if (i % 256 == 0)
709 			pr_info("verified up to eraseblock %u\n", i);
710 
711 		err = mtdtest_relax();
712 		if (err)
713 			goto out;
714 	}
715 	pr_info("verified %u eraseblocks\n", i);
716 
717 	pr_info("finished with %d errors\n", errcnt);
718 out:
719 	kfree(bbt);
720 	kfree(writebuf);
721 	kfree(readbuf);
722 	put_mtd_device(mtd);
723 	if (err)
724 		pr_info("error %d occurred\n", err);
725 	printk(KERN_INFO "=================================================\n");
726 	return err;
727 }
728 module_init(mtd_oobtest_init);
729 
730 static void __exit mtd_oobtest_exit(void)
731 {
732 	return;
733 }
734 module_exit(mtd_oobtest_exit);
735 
736 MODULE_DESCRIPTION("Out-of-band test module");
737 MODULE_AUTHOR("Adrian Hunter");
738 MODULE_LICENSE("GPL");
739