xref: /linux/drivers/mtd/tests/oobtest.c (revision d2b51c808745ca93c020ba34a3cf256ad52adc63)
1 /*
2  * Copyright (C) 2006-2008 Nokia Corporation
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms of the GNU General Public License version 2 as published by
6  * the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
11  * more details.
12  *
13  * You should have received a copy of the GNU General Public License along with
14  * this program; see the file COPYING. If not, write to the Free Software
15  * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
16  *
17  * Test OOB read and write on MTD device.
18  *
19  * Author: Adrian Hunter <ext-adrian.hunter@nokia.com>
20  */
21 
22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 
24 #include <asm/div64.h>
25 #include <linux/init.h>
26 #include <linux/module.h>
27 #include <linux/moduleparam.h>
28 #include <linux/err.h>
29 #include <linux/mtd/mtd.h>
30 #include <linux/slab.h>
31 #include <linux/sched.h>
32 #include <linux/random.h>
33 
34 #include "mtd_test.h"
35 
36 static int dev = -EINVAL;
37 static int bitflip_limit;
38 module_param(dev, int, S_IRUGO);
39 MODULE_PARM_DESC(dev, "MTD device number to use");
40 module_param(bitflip_limit, int, S_IRUGO);
41 MODULE_PARM_DESC(bitflip_limit, "Max. allowed bitflips per page");
42 
43 static struct mtd_info *mtd;
44 static unsigned char *readbuf;
45 static unsigned char *writebuf;
46 static unsigned char *bbt;
47 
48 static int ebcnt;
49 static int pgcnt;
50 static int errcnt;
51 static int use_offset;
52 static int use_len;
53 static int use_len_max;
54 static int vary_offset;
55 static struct rnd_state rnd_state;
56 
57 static void do_vary_offset(void)
58 {
59 	use_len -= 1;
60 	if (use_len < 1) {
61 		use_offset += 1;
62 		if (use_offset >= use_len_max)
63 			use_offset = 0;
64 		use_len = use_len_max - use_offset;
65 	}
66 }
67 
68 static int write_eraseblock(int ebnum)
69 {
70 	int i;
71 	struct mtd_oob_ops ops;
72 	int err = 0;
73 	loff_t addr = (loff_t)ebnum * mtd->erasesize;
74 
75 	prandom_bytes_state(&rnd_state, writebuf, use_len_max * pgcnt);
76 	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
77 		ops.mode      = MTD_OPS_AUTO_OOB;
78 		ops.len       = 0;
79 		ops.retlen    = 0;
80 		ops.ooblen    = use_len;
81 		ops.oobretlen = 0;
82 		ops.ooboffs   = use_offset;
83 		ops.datbuf    = NULL;
84 		ops.oobbuf    = writebuf + (use_len_max * i) + use_offset;
85 		err = mtd_write_oob(mtd, addr, &ops);
86 		if (err || ops.oobretlen != use_len) {
87 			pr_err("error: writeoob failed at %#llx\n",
88 			       (long long)addr);
89 			pr_err("error: use_len %d, use_offset %d\n",
90 			       use_len, use_offset);
91 			errcnt += 1;
92 			return err ? err : -1;
93 		}
94 		if (vary_offset)
95 			do_vary_offset();
96 	}
97 
98 	return err;
99 }
100 
101 static int write_whole_device(void)
102 {
103 	int err;
104 	unsigned int i;
105 
106 	pr_info("writing OOBs of whole device\n");
107 	for (i = 0; i < ebcnt; ++i) {
108 		if (bbt[i])
109 			continue;
110 		err = write_eraseblock(i);
111 		if (err)
112 			return err;
113 		if (i % 256 == 0)
114 			pr_info("written up to eraseblock %u\n", i);
115 		cond_resched();
116 	}
117 	pr_info("written %u eraseblocks\n", i);
118 	return 0;
119 }
120 
121 /*
122  * Display the address, offset and data bytes at comparison failure.
123  * Return number of bitflips encountered.
124  */
125 static size_t memcmpshow(loff_t addr, const void *cs, const void *ct, size_t count)
126 {
127 	const unsigned char *su1, *su2;
128 	int res;
129 	size_t i = 0;
130 	size_t bitflips = 0;
131 
132 	for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--, i++) {
133 		res = *su1 ^ *su2;
134 		if (res) {
135 			pr_info("error @addr[0x%lx:0x%zx] 0x%x -> 0x%x diff 0x%x\n",
136 				(unsigned long)addr, i, *su1, *su2, res);
137 			bitflips += hweight8(res);
138 		}
139 	}
140 
141 	return bitflips;
142 }
143 
144 /*
145  * Compare with 0xff and show the address, offset and data bytes at
146  * comparison failure. Return number of bitflips encountered.
147  */
148 static size_t memffshow(loff_t addr, loff_t offset, const void *cs,
149 			size_t count)
150 {
151 	const unsigned char *su1;
152 	int res;
153 	size_t i = 0;
154 	size_t bitflips = 0;
155 
156 	for (su1 = cs; 0 < count; ++su1, count--, i++) {
157 		res = *su1 ^ 0xff;
158 		if (res) {
159 			pr_info("error @addr[0x%lx:0x%lx] 0x%x -> 0xff diff 0x%x\n",
160 				(unsigned long)addr, (unsigned long)offset + i,
161 				*su1, res);
162 			bitflips += hweight8(res);
163 		}
164 	}
165 
166 	return bitflips;
167 }
168 
169 static int verify_eraseblock(int ebnum)
170 {
171 	int i;
172 	struct mtd_oob_ops ops;
173 	int err = 0;
174 	loff_t addr = (loff_t)ebnum * mtd->erasesize;
175 	size_t bitflips;
176 
177 	prandom_bytes_state(&rnd_state, writebuf, use_len_max * pgcnt);
178 	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
179 		ops.mode      = MTD_OPS_AUTO_OOB;
180 		ops.len       = 0;
181 		ops.retlen    = 0;
182 		ops.ooblen    = use_len;
183 		ops.oobretlen = 0;
184 		ops.ooboffs   = use_offset;
185 		ops.datbuf    = NULL;
186 		ops.oobbuf    = readbuf;
187 		err = mtd_read_oob(mtd, addr, &ops);
188 		if (err || ops.oobretlen != use_len) {
189 			pr_err("error: readoob failed at %#llx\n",
190 			       (long long)addr);
191 			errcnt += 1;
192 			return err ? err : -1;
193 		}
194 
195 		bitflips = memcmpshow(addr, readbuf,
196 				      writebuf + (use_len_max * i) + use_offset,
197 				      use_len);
198 		if (bitflips > bitflip_limit) {
199 			pr_err("error: verify failed at %#llx\n",
200 			       (long long)addr);
201 			errcnt += 1;
202 			if (errcnt > 1000) {
203 				pr_err("error: too many errors\n");
204 				return -1;
205 			}
206 		} else if (bitflips) {
207 			pr_info("ignoring error as within bitflip_limit\n");
208 		}
209 
210 		if (use_offset != 0 || use_len < mtd->ecclayout->oobavail) {
211 			int k;
212 
213 			ops.mode      = MTD_OPS_AUTO_OOB;
214 			ops.len       = 0;
215 			ops.retlen    = 0;
216 			ops.ooblen    = mtd->ecclayout->oobavail;
217 			ops.oobretlen = 0;
218 			ops.ooboffs   = 0;
219 			ops.datbuf    = NULL;
220 			ops.oobbuf    = readbuf;
221 			err = mtd_read_oob(mtd, addr, &ops);
222 			if (err || ops.oobretlen != mtd->ecclayout->oobavail) {
223 				pr_err("error: readoob failed at %#llx\n",
224 						(long long)addr);
225 				errcnt += 1;
226 				return err ? err : -1;
227 			}
228 			bitflips = memcmpshow(addr, readbuf + use_offset,
229 					      writebuf + (use_len_max * i) + use_offset,
230 					      use_len);
231 
232 			/* verify pre-offset area for 0xff */
233 			bitflips += memffshow(addr, 0, readbuf, use_offset);
234 
235 			/* verify post-(use_offset + use_len) area for 0xff */
236 			k = use_offset + use_len;
237 			bitflips += memffshow(addr, k, readbuf + k,
238 					      mtd->ecclayout->oobavail - k);
239 
240 			if (bitflips > bitflip_limit) {
241 				pr_err("error: verify failed at %#llx\n",
242 						(long long)addr);
243 				errcnt += 1;
244 				if (errcnt > 1000) {
245 					pr_err("error: too many errors\n");
246 					return -1;
247 				}
248 			} else if (bitflips) {
249 				pr_info("ignoring errors as within bitflip limit\n");
250 			}
251 		}
252 		if (vary_offset)
253 			do_vary_offset();
254 	}
255 	return err;
256 }
257 
258 static int verify_eraseblock_in_one_go(int ebnum)
259 {
260 	struct mtd_oob_ops ops;
261 	int err = 0;
262 	loff_t addr = (loff_t)ebnum * mtd->erasesize;
263 	size_t len = mtd->ecclayout->oobavail * pgcnt;
264 	size_t oobavail = mtd->ecclayout->oobavail;
265 	size_t bitflips;
266 	int i;
267 
268 	prandom_bytes_state(&rnd_state, writebuf, len);
269 	ops.mode      = MTD_OPS_AUTO_OOB;
270 	ops.len       = 0;
271 	ops.retlen    = 0;
272 	ops.ooblen    = len;
273 	ops.oobretlen = 0;
274 	ops.ooboffs   = 0;
275 	ops.datbuf    = NULL;
276 	ops.oobbuf    = readbuf;
277 
278 	/* read entire block's OOB at one go */
279 	err = mtd_read_oob(mtd, addr, &ops);
280 	if (err || ops.oobretlen != len) {
281 		pr_err("error: readoob failed at %#llx\n",
282 		       (long long)addr);
283 		errcnt += 1;
284 		return err ? err : -1;
285 	}
286 
287 	/* verify one page OOB at a time for bitflip per page limit check */
288 	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
289 		bitflips = memcmpshow(addr, readbuf + (i * oobavail),
290 				      writebuf + (i * oobavail), oobavail);
291 		if (bitflips > bitflip_limit) {
292 			pr_err("error: verify failed at %#llx\n",
293 			       (long long)addr);
294 			errcnt += 1;
295 			if (errcnt > 1000) {
296 				pr_err("error: too many errors\n");
297 				return -1;
298 			}
299 		} else if (bitflips) {
300 			pr_info("ignoring error as within bitflip_limit\n");
301 		}
302 	}
303 
304 	return err;
305 }
306 
307 static int verify_all_eraseblocks(void)
308 {
309 	int err;
310 	unsigned int i;
311 
312 	pr_info("verifying all eraseblocks\n");
313 	for (i = 0; i < ebcnt; ++i) {
314 		if (bbt[i])
315 			continue;
316 		err = verify_eraseblock(i);
317 		if (err)
318 			return err;
319 		if (i % 256 == 0)
320 			pr_info("verified up to eraseblock %u\n", i);
321 		cond_resched();
322 	}
323 	pr_info("verified %u eraseblocks\n", i);
324 	return 0;
325 }
326 
327 static int __init mtd_oobtest_init(void)
328 {
329 	int err = 0;
330 	unsigned int i;
331 	uint64_t tmp;
332 	struct mtd_oob_ops ops;
333 	loff_t addr = 0, addr0;
334 
335 	printk(KERN_INFO "\n");
336 	printk(KERN_INFO "=================================================\n");
337 
338 	if (dev < 0) {
339 		pr_info("Please specify a valid mtd-device via module parameter\n");
340 		pr_crit("CAREFUL: This test wipes all data on the specified MTD device!\n");
341 		return -EINVAL;
342 	}
343 
344 	pr_info("MTD device: %d\n", dev);
345 
346 	mtd = get_mtd_device(NULL, dev);
347 	if (IS_ERR(mtd)) {
348 		err = PTR_ERR(mtd);
349 		pr_err("error: cannot get MTD device\n");
350 		return err;
351 	}
352 
353 	if (!mtd_type_is_nand(mtd)) {
354 		pr_info("this test requires NAND flash\n");
355 		goto out;
356 	}
357 
358 	tmp = mtd->size;
359 	do_div(tmp, mtd->erasesize);
360 	ebcnt = tmp;
361 	pgcnt = mtd->erasesize / mtd->writesize;
362 
363 	pr_info("MTD device size %llu, eraseblock size %u, "
364 	       "page size %u, count of eraseblocks %u, pages per "
365 	       "eraseblock %u, OOB size %u\n",
366 	       (unsigned long long)mtd->size, mtd->erasesize,
367 	       mtd->writesize, ebcnt, pgcnt, mtd->oobsize);
368 
369 	err = -ENOMEM;
370 	readbuf = kmalloc(mtd->erasesize, GFP_KERNEL);
371 	if (!readbuf)
372 		goto out;
373 	writebuf = kmalloc(mtd->erasesize, GFP_KERNEL);
374 	if (!writebuf)
375 		goto out;
376 	bbt = kzalloc(ebcnt, GFP_KERNEL);
377 	if (!bbt)
378 		goto out;
379 
380 	err = mtdtest_scan_for_bad_eraseblocks(mtd, bbt, 0, ebcnt);
381 	if (err)
382 		goto out;
383 
384 	use_offset = 0;
385 	use_len = mtd->ecclayout->oobavail;
386 	use_len_max = mtd->ecclayout->oobavail;
387 	vary_offset = 0;
388 
389 	/* First test: write all OOB, read it back and verify */
390 	pr_info("test 1 of 5\n");
391 
392 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
393 	if (err)
394 		goto out;
395 
396 	prandom_seed_state(&rnd_state, 1);
397 	err = write_whole_device();
398 	if (err)
399 		goto out;
400 
401 	prandom_seed_state(&rnd_state, 1);
402 	err = verify_all_eraseblocks();
403 	if (err)
404 		goto out;
405 
406 	/*
407 	 * Second test: write all OOB, a block at a time, read it back and
408 	 * verify.
409 	 */
410 	pr_info("test 2 of 5\n");
411 
412 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
413 	if (err)
414 		goto out;
415 
416 	prandom_seed_state(&rnd_state, 3);
417 	err = write_whole_device();
418 	if (err)
419 		goto out;
420 
421 	/* Check all eraseblocks */
422 	prandom_seed_state(&rnd_state, 3);
423 	pr_info("verifying all eraseblocks\n");
424 	for (i = 0; i < ebcnt; ++i) {
425 		if (bbt[i])
426 			continue;
427 		err = verify_eraseblock_in_one_go(i);
428 		if (err)
429 			goto out;
430 		if (i % 256 == 0)
431 			pr_info("verified up to eraseblock %u\n", i);
432 		cond_resched();
433 	}
434 	pr_info("verified %u eraseblocks\n", i);
435 
436 	/*
437 	 * Third test: write OOB at varying offsets and lengths, read it back
438 	 * and verify.
439 	 */
440 	pr_info("test 3 of 5\n");
441 
442 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
443 	if (err)
444 		goto out;
445 
446 	/* Write all eraseblocks */
447 	use_offset = 0;
448 	use_len = mtd->ecclayout->oobavail;
449 	use_len_max = mtd->ecclayout->oobavail;
450 	vary_offset = 1;
451 	prandom_seed_state(&rnd_state, 5);
452 
453 	err = write_whole_device();
454 	if (err)
455 		goto out;
456 
457 	/* Check all eraseblocks */
458 	use_offset = 0;
459 	use_len = mtd->ecclayout->oobavail;
460 	use_len_max = mtd->ecclayout->oobavail;
461 	vary_offset = 1;
462 	prandom_seed_state(&rnd_state, 5);
463 	err = verify_all_eraseblocks();
464 	if (err)
465 		goto out;
466 
467 	use_offset = 0;
468 	use_len = mtd->ecclayout->oobavail;
469 	use_len_max = mtd->ecclayout->oobavail;
470 	vary_offset = 0;
471 
472 	/* Fourth test: try to write off end of device */
473 	pr_info("test 4 of 5\n");
474 
475 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
476 	if (err)
477 		goto out;
478 
479 	addr0 = 0;
480 	for (i = 0; i < ebcnt && bbt[i]; ++i)
481 		addr0 += mtd->erasesize;
482 
483 	/* Attempt to write off end of OOB */
484 	ops.mode      = MTD_OPS_AUTO_OOB;
485 	ops.len       = 0;
486 	ops.retlen    = 0;
487 	ops.ooblen    = 1;
488 	ops.oobretlen = 0;
489 	ops.ooboffs   = mtd->ecclayout->oobavail;
490 	ops.datbuf    = NULL;
491 	ops.oobbuf    = writebuf;
492 	pr_info("attempting to start write past end of OOB\n");
493 	pr_info("an error is expected...\n");
494 	err = mtd_write_oob(mtd, addr0, &ops);
495 	if (err) {
496 		pr_info("error occurred as expected\n");
497 		err = 0;
498 	} else {
499 		pr_err("error: can write past end of OOB\n");
500 		errcnt += 1;
501 	}
502 
503 	/* Attempt to read off end of OOB */
504 	ops.mode      = MTD_OPS_AUTO_OOB;
505 	ops.len       = 0;
506 	ops.retlen    = 0;
507 	ops.ooblen    = 1;
508 	ops.oobretlen = 0;
509 	ops.ooboffs   = mtd->ecclayout->oobavail;
510 	ops.datbuf    = NULL;
511 	ops.oobbuf    = readbuf;
512 	pr_info("attempting to start read past end of OOB\n");
513 	pr_info("an error is expected...\n");
514 	err = mtd_read_oob(mtd, addr0, &ops);
515 	if (err) {
516 		pr_info("error occurred as expected\n");
517 		err = 0;
518 	} else {
519 		pr_err("error: can read past end of OOB\n");
520 		errcnt += 1;
521 	}
522 
523 	if (bbt[ebcnt - 1])
524 		pr_info("skipping end of device tests because last "
525 		       "block is bad\n");
526 	else {
527 		/* Attempt to write off end of device */
528 		ops.mode      = MTD_OPS_AUTO_OOB;
529 		ops.len       = 0;
530 		ops.retlen    = 0;
531 		ops.ooblen    = mtd->ecclayout->oobavail + 1;
532 		ops.oobretlen = 0;
533 		ops.ooboffs   = 0;
534 		ops.datbuf    = NULL;
535 		ops.oobbuf    = writebuf;
536 		pr_info("attempting to write past end of device\n");
537 		pr_info("an error is expected...\n");
538 		err = mtd_write_oob(mtd, mtd->size - mtd->writesize, &ops);
539 		if (err) {
540 			pr_info("error occurred as expected\n");
541 			err = 0;
542 		} else {
543 			pr_err("error: wrote past end of device\n");
544 			errcnt += 1;
545 		}
546 
547 		/* Attempt to read off end of device */
548 		ops.mode      = MTD_OPS_AUTO_OOB;
549 		ops.len       = 0;
550 		ops.retlen    = 0;
551 		ops.ooblen    = mtd->ecclayout->oobavail + 1;
552 		ops.oobretlen = 0;
553 		ops.ooboffs   = 0;
554 		ops.datbuf    = NULL;
555 		ops.oobbuf    = readbuf;
556 		pr_info("attempting to read past end of device\n");
557 		pr_info("an error is expected...\n");
558 		err = mtd_read_oob(mtd, mtd->size - mtd->writesize, &ops);
559 		if (err) {
560 			pr_info("error occurred as expected\n");
561 			err = 0;
562 		} else {
563 			pr_err("error: read past end of device\n");
564 			errcnt += 1;
565 		}
566 
567 		err = mtdtest_erase_eraseblock(mtd, ebcnt - 1);
568 		if (err)
569 			goto out;
570 
571 		/* Attempt to write off end of device */
572 		ops.mode      = MTD_OPS_AUTO_OOB;
573 		ops.len       = 0;
574 		ops.retlen    = 0;
575 		ops.ooblen    = mtd->ecclayout->oobavail;
576 		ops.oobretlen = 0;
577 		ops.ooboffs   = 1;
578 		ops.datbuf    = NULL;
579 		ops.oobbuf    = writebuf;
580 		pr_info("attempting to write past end of device\n");
581 		pr_info("an error is expected...\n");
582 		err = mtd_write_oob(mtd, mtd->size - mtd->writesize, &ops);
583 		if (err) {
584 			pr_info("error occurred as expected\n");
585 			err = 0;
586 		} else {
587 			pr_err("error: wrote past end of device\n");
588 			errcnt += 1;
589 		}
590 
591 		/* Attempt to read off end of device */
592 		ops.mode      = MTD_OPS_AUTO_OOB;
593 		ops.len       = 0;
594 		ops.retlen    = 0;
595 		ops.ooblen    = mtd->ecclayout->oobavail;
596 		ops.oobretlen = 0;
597 		ops.ooboffs   = 1;
598 		ops.datbuf    = NULL;
599 		ops.oobbuf    = readbuf;
600 		pr_info("attempting to read past end of device\n");
601 		pr_info("an error is expected...\n");
602 		err = mtd_read_oob(mtd, mtd->size - mtd->writesize, &ops);
603 		if (err) {
604 			pr_info("error occurred as expected\n");
605 			err = 0;
606 		} else {
607 			pr_err("error: read past end of device\n");
608 			errcnt += 1;
609 		}
610 	}
611 
612 	/* Fifth test: write / read across block boundaries */
613 	pr_info("test 5 of 5\n");
614 
615 	/* Erase all eraseblocks */
616 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
617 	if (err)
618 		goto out;
619 
620 	/* Write all eraseblocks */
621 	prandom_seed_state(&rnd_state, 11);
622 	pr_info("writing OOBs of whole device\n");
623 	for (i = 0; i < ebcnt - 1; ++i) {
624 		int cnt = 2;
625 		int pg;
626 		size_t sz = mtd->ecclayout->oobavail;
627 		if (bbt[i] || bbt[i + 1])
628 			continue;
629 		addr = (loff_t)(i + 1) * mtd->erasesize - mtd->writesize;
630 		prandom_bytes_state(&rnd_state, writebuf, sz * cnt);
631 		for (pg = 0; pg < cnt; ++pg) {
632 			ops.mode      = MTD_OPS_AUTO_OOB;
633 			ops.len       = 0;
634 			ops.retlen    = 0;
635 			ops.ooblen    = sz;
636 			ops.oobretlen = 0;
637 			ops.ooboffs   = 0;
638 			ops.datbuf    = NULL;
639 			ops.oobbuf    = writebuf + pg * sz;
640 			err = mtd_write_oob(mtd, addr, &ops);
641 			if (err)
642 				goto out;
643 			if (i % 256 == 0)
644 				pr_info("written up to eraseblock %u\n", i);
645 			cond_resched();
646 			addr += mtd->writesize;
647 		}
648 	}
649 	pr_info("written %u eraseblocks\n", i);
650 
651 	/* Check all eraseblocks */
652 	prandom_seed_state(&rnd_state, 11);
653 	pr_info("verifying all eraseblocks\n");
654 	for (i = 0; i < ebcnt - 1; ++i) {
655 		if (bbt[i] || bbt[i + 1])
656 			continue;
657 		prandom_bytes_state(&rnd_state, writebuf,
658 					mtd->ecclayout->oobavail * 2);
659 		addr = (loff_t)(i + 1) * mtd->erasesize - mtd->writesize;
660 		ops.mode      = MTD_OPS_AUTO_OOB;
661 		ops.len       = 0;
662 		ops.retlen    = 0;
663 		ops.ooblen    = mtd->ecclayout->oobavail * 2;
664 		ops.oobretlen = 0;
665 		ops.ooboffs   = 0;
666 		ops.datbuf    = NULL;
667 		ops.oobbuf    = readbuf;
668 		err = mtd_read_oob(mtd, addr, &ops);
669 		if (err)
670 			goto out;
671 		if (memcmpshow(addr, readbuf, writebuf,
672 			       mtd->ecclayout->oobavail * 2)) {
673 			pr_err("error: verify failed at %#llx\n",
674 			       (long long)addr);
675 			errcnt += 1;
676 			if (errcnt > 1000) {
677 				pr_err("error: too many errors\n");
678 				goto out;
679 			}
680 		}
681 		if (i % 256 == 0)
682 			pr_info("verified up to eraseblock %u\n", i);
683 		cond_resched();
684 	}
685 	pr_info("verified %u eraseblocks\n", i);
686 
687 	pr_info("finished with %d errors\n", errcnt);
688 out:
689 	kfree(bbt);
690 	kfree(writebuf);
691 	kfree(readbuf);
692 	put_mtd_device(mtd);
693 	if (err)
694 		pr_info("error %d occurred\n", err);
695 	printk(KERN_INFO "=================================================\n");
696 	return err;
697 }
698 module_init(mtd_oobtest_init);
699 
700 static void __exit mtd_oobtest_exit(void)
701 {
702 	return;
703 }
704 module_exit(mtd_oobtest_exit);
705 
706 MODULE_DESCRIPTION("Out-of-band test module");
707 MODULE_AUTHOR("Adrian Hunter");
708 MODULE_LICENSE("GPL");
709