xref: /linux/drivers/mtd/tests/oobtest.c (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
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 
116 		err = mtdtest_relax();
117 		if (err)
118 			return err;
119 	}
120 	pr_info("written %u eraseblocks\n", i);
121 	return 0;
122 }
123 
124 /*
125  * Display the address, offset and data bytes at comparison failure.
126  * Return number of bitflips encountered.
127  */
128 static size_t memcmpshowoffset(loff_t addr, loff_t offset, const void *cs,
129 			       const void *ct, size_t count)
130 {
131 	const unsigned char *su1, *su2;
132 	int res;
133 	size_t i = 0;
134 	size_t bitflips = 0;
135 
136 	for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--, i++) {
137 		res = *su1 ^ *su2;
138 		if (res) {
139 			pr_info("error @addr[0x%lx:0x%lx] 0x%x -> 0x%x diff 0x%x\n",
140 				(unsigned long)addr, (unsigned long)offset + i,
141 				*su1, *su2, res);
142 			bitflips += hweight8(res);
143 		}
144 	}
145 
146 	return bitflips;
147 }
148 
149 #define memcmpshow(addr, cs, ct, count) memcmpshowoffset((addr), 0, (cs), (ct),\
150 							 (count))
151 
152 /*
153  * Compare with 0xff and show the address, offset and data bytes at
154  * comparison failure. Return number of bitflips encountered.
155  */
156 static size_t memffshow(loff_t addr, loff_t offset, const void *cs,
157 			size_t count)
158 {
159 	const unsigned char *su1;
160 	int res;
161 	size_t i = 0;
162 	size_t bitflips = 0;
163 
164 	for (su1 = cs; 0 < count; ++su1, count--, i++) {
165 		res = *su1 ^ 0xff;
166 		if (res) {
167 			pr_info("error @addr[0x%lx:0x%lx] 0x%x -> 0xff diff 0x%x\n",
168 				(unsigned long)addr, (unsigned long)offset + i,
169 				*su1, res);
170 			bitflips += hweight8(res);
171 		}
172 	}
173 
174 	return bitflips;
175 }
176 
177 static int verify_eraseblock(int ebnum)
178 {
179 	int i;
180 	struct mtd_oob_ops ops;
181 	int err = 0;
182 	loff_t addr = (loff_t)ebnum * mtd->erasesize;
183 	size_t bitflips;
184 
185 	prandom_bytes_state(&rnd_state, writebuf, use_len_max * pgcnt);
186 	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
187 		ops.mode      = MTD_OPS_AUTO_OOB;
188 		ops.len       = 0;
189 		ops.retlen    = 0;
190 		ops.ooblen    = use_len;
191 		ops.oobretlen = 0;
192 		ops.ooboffs   = use_offset;
193 		ops.datbuf    = NULL;
194 		ops.oobbuf    = readbuf;
195 		err = mtd_read_oob(mtd, addr, &ops);
196 		if (err || ops.oobretlen != use_len) {
197 			pr_err("error: readoob failed at %#llx\n",
198 			       (long long)addr);
199 			errcnt += 1;
200 			return err ? err : -1;
201 		}
202 
203 		bitflips = memcmpshow(addr, readbuf,
204 				      writebuf + (use_len_max * i) + use_offset,
205 				      use_len);
206 		if (bitflips > bitflip_limit) {
207 			pr_err("error: verify failed at %#llx\n",
208 			       (long long)addr);
209 			errcnt += 1;
210 			if (errcnt > 1000) {
211 				pr_err("error: too many errors\n");
212 				return -1;
213 			}
214 		} else if (bitflips) {
215 			pr_info("ignoring error as within bitflip_limit\n");
216 		}
217 
218 		if (use_offset != 0 || use_len < mtd->ecclayout->oobavail) {
219 			int k;
220 
221 			ops.mode      = MTD_OPS_AUTO_OOB;
222 			ops.len       = 0;
223 			ops.retlen    = 0;
224 			ops.ooblen    = mtd->ecclayout->oobavail;
225 			ops.oobretlen = 0;
226 			ops.ooboffs   = 0;
227 			ops.datbuf    = NULL;
228 			ops.oobbuf    = readbuf;
229 			err = mtd_read_oob(mtd, addr, &ops);
230 			if (err || ops.oobretlen != mtd->ecclayout->oobavail) {
231 				pr_err("error: readoob failed at %#llx\n",
232 						(long long)addr);
233 				errcnt += 1;
234 				return err ? err : -1;
235 			}
236 			bitflips = memcmpshowoffset(addr, use_offset,
237 						    readbuf + use_offset,
238 						    writebuf + (use_len_max * i) + use_offset,
239 						    use_len);
240 
241 			/* verify pre-offset area for 0xff */
242 			bitflips += memffshow(addr, 0, readbuf, use_offset);
243 
244 			/* verify post-(use_offset + use_len) area for 0xff */
245 			k = use_offset + use_len;
246 			bitflips += memffshow(addr, k, readbuf + k,
247 					      mtd->ecclayout->oobavail - k);
248 
249 			if (bitflips > bitflip_limit) {
250 				pr_err("error: verify failed at %#llx\n",
251 						(long long)addr);
252 				errcnt += 1;
253 				if (errcnt > 1000) {
254 					pr_err("error: too many errors\n");
255 					return -1;
256 				}
257 			} else if (bitflips) {
258 				pr_info("ignoring errors as within bitflip limit\n");
259 			}
260 		}
261 		if (vary_offset)
262 			do_vary_offset();
263 	}
264 	return err;
265 }
266 
267 static int verify_eraseblock_in_one_go(int ebnum)
268 {
269 	struct mtd_oob_ops ops;
270 	int err = 0;
271 	loff_t addr = (loff_t)ebnum * mtd->erasesize;
272 	size_t len = mtd->ecclayout->oobavail * pgcnt;
273 	size_t oobavail = mtd->ecclayout->oobavail;
274 	size_t bitflips;
275 	int i;
276 
277 	prandom_bytes_state(&rnd_state, writebuf, len);
278 	ops.mode      = MTD_OPS_AUTO_OOB;
279 	ops.len       = 0;
280 	ops.retlen    = 0;
281 	ops.ooblen    = len;
282 	ops.oobretlen = 0;
283 	ops.ooboffs   = 0;
284 	ops.datbuf    = NULL;
285 	ops.oobbuf    = readbuf;
286 
287 	/* read entire block's OOB at one go */
288 	err = mtd_read_oob(mtd, addr, &ops);
289 	if (err || ops.oobretlen != len) {
290 		pr_err("error: readoob failed at %#llx\n",
291 		       (long long)addr);
292 		errcnt += 1;
293 		return err ? err : -1;
294 	}
295 
296 	/* verify one page OOB at a time for bitflip per page limit check */
297 	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
298 		bitflips = memcmpshow(addr, readbuf + (i * oobavail),
299 				      writebuf + (i * oobavail), oobavail);
300 		if (bitflips > bitflip_limit) {
301 			pr_err("error: verify failed at %#llx\n",
302 			       (long long)addr);
303 			errcnt += 1;
304 			if (errcnt > 1000) {
305 				pr_err("error: too many errors\n");
306 				return -1;
307 			}
308 		} else if (bitflips) {
309 			pr_info("ignoring error as within bitflip_limit\n");
310 		}
311 	}
312 
313 	return err;
314 }
315 
316 static int verify_all_eraseblocks(void)
317 {
318 	int err;
319 	unsigned int i;
320 
321 	pr_info("verifying all eraseblocks\n");
322 	for (i = 0; i < ebcnt; ++i) {
323 		if (bbt[i])
324 			continue;
325 		err = verify_eraseblock(i);
326 		if (err)
327 			return err;
328 		if (i % 256 == 0)
329 			pr_info("verified up to eraseblock %u\n", i);
330 
331 		err = mtdtest_relax();
332 		if (err)
333 			return err;
334 	}
335 	pr_info("verified %u eraseblocks\n", i);
336 	return 0;
337 }
338 
339 static int __init mtd_oobtest_init(void)
340 {
341 	int err = 0;
342 	unsigned int i;
343 	uint64_t tmp;
344 	struct mtd_oob_ops ops;
345 	loff_t addr = 0, addr0;
346 
347 	printk(KERN_INFO "\n");
348 	printk(KERN_INFO "=================================================\n");
349 
350 	if (dev < 0) {
351 		pr_info("Please specify a valid mtd-device via module parameter\n");
352 		pr_crit("CAREFUL: This test wipes all data on the specified MTD device!\n");
353 		return -EINVAL;
354 	}
355 
356 	pr_info("MTD device: %d\n", dev);
357 
358 	mtd = get_mtd_device(NULL, dev);
359 	if (IS_ERR(mtd)) {
360 		err = PTR_ERR(mtd);
361 		pr_err("error: cannot get MTD device\n");
362 		return err;
363 	}
364 
365 	if (!mtd_type_is_nand(mtd)) {
366 		pr_info("this test requires NAND flash\n");
367 		goto out;
368 	}
369 
370 	tmp = mtd->size;
371 	do_div(tmp, mtd->erasesize);
372 	ebcnt = tmp;
373 	pgcnt = mtd->erasesize / mtd->writesize;
374 
375 	pr_info("MTD device size %llu, eraseblock size %u, "
376 	       "page size %u, count of eraseblocks %u, pages per "
377 	       "eraseblock %u, OOB size %u\n",
378 	       (unsigned long long)mtd->size, mtd->erasesize,
379 	       mtd->writesize, ebcnt, pgcnt, mtd->oobsize);
380 
381 	err = -ENOMEM;
382 	readbuf = kmalloc(mtd->erasesize, GFP_KERNEL);
383 	if (!readbuf)
384 		goto out;
385 	writebuf = kmalloc(mtd->erasesize, GFP_KERNEL);
386 	if (!writebuf)
387 		goto out;
388 	bbt = kzalloc(ebcnt, GFP_KERNEL);
389 	if (!bbt)
390 		goto out;
391 
392 	err = mtdtest_scan_for_bad_eraseblocks(mtd, bbt, 0, ebcnt);
393 	if (err)
394 		goto out;
395 
396 	use_offset = 0;
397 	use_len = mtd->ecclayout->oobavail;
398 	use_len_max = mtd->ecclayout->oobavail;
399 	vary_offset = 0;
400 
401 	/* First test: write all OOB, read it back and verify */
402 	pr_info("test 1 of 5\n");
403 
404 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
405 	if (err)
406 		goto out;
407 
408 	prandom_seed_state(&rnd_state, 1);
409 	err = write_whole_device();
410 	if (err)
411 		goto out;
412 
413 	prandom_seed_state(&rnd_state, 1);
414 	err = verify_all_eraseblocks();
415 	if (err)
416 		goto out;
417 
418 	/*
419 	 * Second test: write all OOB, a block at a time, read it back and
420 	 * verify.
421 	 */
422 	pr_info("test 2 of 5\n");
423 
424 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
425 	if (err)
426 		goto out;
427 
428 	prandom_seed_state(&rnd_state, 3);
429 	err = write_whole_device();
430 	if (err)
431 		goto out;
432 
433 	/* Check all eraseblocks */
434 	prandom_seed_state(&rnd_state, 3);
435 	pr_info("verifying all eraseblocks\n");
436 	for (i = 0; i < ebcnt; ++i) {
437 		if (bbt[i])
438 			continue;
439 		err = verify_eraseblock_in_one_go(i);
440 		if (err)
441 			goto out;
442 		if (i % 256 == 0)
443 			pr_info("verified up to eraseblock %u\n", i);
444 
445 		err = mtdtest_relax();
446 		if (err)
447 			goto out;
448 	}
449 	pr_info("verified %u eraseblocks\n", i);
450 
451 	/*
452 	 * Third test: write OOB at varying offsets and lengths, read it back
453 	 * and verify.
454 	 */
455 	pr_info("test 3 of 5\n");
456 
457 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
458 	if (err)
459 		goto out;
460 
461 	/* Write all eraseblocks */
462 	use_offset = 0;
463 	use_len = mtd->ecclayout->oobavail;
464 	use_len_max = mtd->ecclayout->oobavail;
465 	vary_offset = 1;
466 	prandom_seed_state(&rnd_state, 5);
467 
468 	err = write_whole_device();
469 	if (err)
470 		goto out;
471 
472 	/* Check all eraseblocks */
473 	use_offset = 0;
474 	use_len = mtd->ecclayout->oobavail;
475 	use_len_max = mtd->ecclayout->oobavail;
476 	vary_offset = 1;
477 	prandom_seed_state(&rnd_state, 5);
478 	err = verify_all_eraseblocks();
479 	if (err)
480 		goto out;
481 
482 	use_offset = 0;
483 	use_len = mtd->ecclayout->oobavail;
484 	use_len_max = mtd->ecclayout->oobavail;
485 	vary_offset = 0;
486 
487 	/* Fourth test: try to write off end of device */
488 	pr_info("test 4 of 5\n");
489 
490 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
491 	if (err)
492 		goto out;
493 
494 	addr0 = 0;
495 	for (i = 0; i < ebcnt && bbt[i]; ++i)
496 		addr0 += mtd->erasesize;
497 
498 	/* Attempt to write off end of OOB */
499 	ops.mode      = MTD_OPS_AUTO_OOB;
500 	ops.len       = 0;
501 	ops.retlen    = 0;
502 	ops.ooblen    = 1;
503 	ops.oobretlen = 0;
504 	ops.ooboffs   = mtd->ecclayout->oobavail;
505 	ops.datbuf    = NULL;
506 	ops.oobbuf    = writebuf;
507 	pr_info("attempting to start write past end of OOB\n");
508 	pr_info("an error is expected...\n");
509 	err = mtd_write_oob(mtd, addr0, &ops);
510 	if (err) {
511 		pr_info("error occurred as expected\n");
512 		err = 0;
513 	} else {
514 		pr_err("error: can write past end of OOB\n");
515 		errcnt += 1;
516 	}
517 
518 	/* Attempt to read off end of OOB */
519 	ops.mode      = MTD_OPS_AUTO_OOB;
520 	ops.len       = 0;
521 	ops.retlen    = 0;
522 	ops.ooblen    = 1;
523 	ops.oobretlen = 0;
524 	ops.ooboffs   = mtd->ecclayout->oobavail;
525 	ops.datbuf    = NULL;
526 	ops.oobbuf    = readbuf;
527 	pr_info("attempting to start read past end of OOB\n");
528 	pr_info("an error is expected...\n");
529 	err = mtd_read_oob(mtd, addr0, &ops);
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->ecclayout->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->ecclayout->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 (err) {
575 			pr_info("error occurred as expected\n");
576 			err = 0;
577 		} else {
578 			pr_err("error: read past end of device\n");
579 			errcnt += 1;
580 		}
581 
582 		err = mtdtest_erase_eraseblock(mtd, ebcnt - 1);
583 		if (err)
584 			goto out;
585 
586 		/* Attempt to write off end of device */
587 		ops.mode      = MTD_OPS_AUTO_OOB;
588 		ops.len       = 0;
589 		ops.retlen    = 0;
590 		ops.ooblen    = mtd->ecclayout->oobavail;
591 		ops.oobretlen = 0;
592 		ops.ooboffs   = 1;
593 		ops.datbuf    = NULL;
594 		ops.oobbuf    = writebuf;
595 		pr_info("attempting to write past end of device\n");
596 		pr_info("an error is expected...\n");
597 		err = mtd_write_oob(mtd, mtd->size - mtd->writesize, &ops);
598 		if (err) {
599 			pr_info("error occurred as expected\n");
600 			err = 0;
601 		} else {
602 			pr_err("error: wrote past end of device\n");
603 			errcnt += 1;
604 		}
605 
606 		/* Attempt to read off end of device */
607 		ops.mode      = MTD_OPS_AUTO_OOB;
608 		ops.len       = 0;
609 		ops.retlen    = 0;
610 		ops.ooblen    = mtd->ecclayout->oobavail;
611 		ops.oobretlen = 0;
612 		ops.ooboffs   = 1;
613 		ops.datbuf    = NULL;
614 		ops.oobbuf    = readbuf;
615 		pr_info("attempting to read past end of device\n");
616 		pr_info("an error is expected...\n");
617 		err = mtd_read_oob(mtd, mtd->size - mtd->writesize, &ops);
618 		if (err) {
619 			pr_info("error occurred as expected\n");
620 			err = 0;
621 		} else {
622 			pr_err("error: read past end of device\n");
623 			errcnt += 1;
624 		}
625 	}
626 
627 	/* Fifth test: write / read across block boundaries */
628 	pr_info("test 5 of 5\n");
629 
630 	/* Erase all eraseblocks */
631 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
632 	if (err)
633 		goto out;
634 
635 	/* Write all eraseblocks */
636 	prandom_seed_state(&rnd_state, 11);
637 	pr_info("writing OOBs of whole device\n");
638 	for (i = 0; i < ebcnt - 1; ++i) {
639 		int cnt = 2;
640 		int pg;
641 		size_t sz = mtd->ecclayout->oobavail;
642 		if (bbt[i] || bbt[i + 1])
643 			continue;
644 		addr = (loff_t)(i + 1) * mtd->erasesize - mtd->writesize;
645 		prandom_bytes_state(&rnd_state, writebuf, sz * cnt);
646 		for (pg = 0; pg < cnt; ++pg) {
647 			ops.mode      = MTD_OPS_AUTO_OOB;
648 			ops.len       = 0;
649 			ops.retlen    = 0;
650 			ops.ooblen    = sz;
651 			ops.oobretlen = 0;
652 			ops.ooboffs   = 0;
653 			ops.datbuf    = NULL;
654 			ops.oobbuf    = writebuf + pg * sz;
655 			err = mtd_write_oob(mtd, addr, &ops);
656 			if (err)
657 				goto out;
658 			if (i % 256 == 0)
659 				pr_info("written up to eraseblock %u\n", i);
660 
661 			err = mtdtest_relax();
662 			if (err)
663 				goto out;
664 
665 			addr += mtd->writesize;
666 		}
667 	}
668 	pr_info("written %u eraseblocks\n", i);
669 
670 	/* Check all eraseblocks */
671 	prandom_seed_state(&rnd_state, 11);
672 	pr_info("verifying all eraseblocks\n");
673 	for (i = 0; i < ebcnt - 1; ++i) {
674 		if (bbt[i] || bbt[i + 1])
675 			continue;
676 		prandom_bytes_state(&rnd_state, writebuf,
677 					mtd->ecclayout->oobavail * 2);
678 		addr = (loff_t)(i + 1) * mtd->erasesize - mtd->writesize;
679 		ops.mode      = MTD_OPS_AUTO_OOB;
680 		ops.len       = 0;
681 		ops.retlen    = 0;
682 		ops.ooblen    = mtd->ecclayout->oobavail * 2;
683 		ops.oobretlen = 0;
684 		ops.ooboffs   = 0;
685 		ops.datbuf    = NULL;
686 		ops.oobbuf    = readbuf;
687 		err = mtd_read_oob(mtd, addr, &ops);
688 		if (err)
689 			goto out;
690 		if (memcmpshow(addr, readbuf, writebuf,
691 			       mtd->ecclayout->oobavail * 2)) {
692 			pr_err("error: verify failed at %#llx\n",
693 			       (long long)addr);
694 			errcnt += 1;
695 			if (errcnt > 1000) {
696 				pr_err("error: too many errors\n");
697 				goto out;
698 			}
699 		}
700 		if (i % 256 == 0)
701 			pr_info("verified up to eraseblock %u\n", i);
702 
703 		err = mtdtest_relax();
704 		if (err)
705 			goto out;
706 	}
707 	pr_info("verified %u eraseblocks\n", i);
708 
709 	pr_info("finished with %d errors\n", errcnt);
710 out:
711 	kfree(bbt);
712 	kfree(writebuf);
713 	kfree(readbuf);
714 	put_mtd_device(mtd);
715 	if (err)
716 		pr_info("error %d occurred\n", err);
717 	printk(KERN_INFO "=================================================\n");
718 	return err;
719 }
720 module_init(mtd_oobtest_init);
721 
722 static void __exit mtd_oobtest_exit(void)
723 {
724 	return;
725 }
726 module_exit(mtd_oobtest_exit);
727 
728 MODULE_DESCRIPTION("Out-of-band test module");
729 MODULE_AUTHOR("Adrian Hunter");
730 MODULE_LICENSE("GPL");
731