xref: /linux/drivers/mtd/tests/oobtest.c (revision e0bf6c5ca2d3281f231c5f0c9bf145e9513644de)
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 = 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 static int verify_eraseblock(int ebnum)
145 {
146 	int i;
147 	struct mtd_oob_ops ops;
148 	int err = 0;
149 	loff_t addr = (loff_t)ebnum * mtd->erasesize;
150 	size_t bitflips;
151 
152 	prandom_bytes_state(&rnd_state, writebuf, use_len_max * pgcnt);
153 	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
154 		ops.mode      = MTD_OPS_AUTO_OOB;
155 		ops.len       = 0;
156 		ops.retlen    = 0;
157 		ops.ooblen    = use_len;
158 		ops.oobretlen = 0;
159 		ops.ooboffs   = use_offset;
160 		ops.datbuf    = NULL;
161 		ops.oobbuf    = readbuf;
162 		err = mtd_read_oob(mtd, addr, &ops);
163 		if (err || ops.oobretlen != use_len) {
164 			pr_err("error: readoob failed at %#llx\n",
165 			       (long long)addr);
166 			errcnt += 1;
167 			return err ? err : -1;
168 		}
169 
170 		bitflips = memcmpshow(addr, readbuf,
171 				      writebuf + (use_len_max * i) + use_offset,
172 				      use_len);
173 		if (bitflips > bitflip_limit) {
174 			pr_err("error: verify failed at %#llx\n",
175 			       (long long)addr);
176 			errcnt += 1;
177 			if (errcnt > 1000) {
178 				pr_err("error: too many errors\n");
179 				return -1;
180 			}
181 		} else if (bitflips) {
182 			pr_info("ignoring error as within bitflip_limit\n");
183 		}
184 
185 		if (use_offset != 0 || use_len < mtd->ecclayout->oobavail) {
186 			int k;
187 
188 			ops.mode      = MTD_OPS_AUTO_OOB;
189 			ops.len       = 0;
190 			ops.retlen    = 0;
191 			ops.ooblen    = mtd->ecclayout->oobavail;
192 			ops.oobretlen = 0;
193 			ops.ooboffs   = 0;
194 			ops.datbuf    = NULL;
195 			ops.oobbuf    = readbuf;
196 			err = mtd_read_oob(mtd, addr, &ops);
197 			if (err || ops.oobretlen != mtd->ecclayout->oobavail) {
198 				pr_err("error: readoob failed at %#llx\n",
199 						(long long)addr);
200 				errcnt += 1;
201 				return err ? err : -1;
202 			}
203 			bitflips = memcmpshow(addr, readbuf + use_offset,
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 			for (k = 0; k < use_offset; ++k)
219 				if (readbuf[k] != 0xff) {
220 					pr_err("error: verify 0xff "
221 					       "failed at %#llx\n",
222 					       (long long)addr);
223 					errcnt += 1;
224 					if (errcnt > 1000) {
225 						pr_err("error: too "
226 						       "many errors\n");
227 						return -1;
228 					}
229 				}
230 			for (k = use_offset + use_len;
231 			     k < mtd->ecclayout->oobavail; ++k)
232 				if (readbuf[k] != 0xff) {
233 					pr_err("error: verify 0xff "
234 					       "failed at %#llx\n",
235 					       (long long)addr);
236 					errcnt += 1;
237 					if (errcnt > 1000) {
238 						pr_err("error: too "
239 						       "many errors\n");
240 						return -1;
241 					}
242 				}
243 		}
244 		if (vary_offset)
245 			do_vary_offset();
246 	}
247 	return err;
248 }
249 
250 static int verify_eraseblock_in_one_go(int ebnum)
251 {
252 	struct mtd_oob_ops ops;
253 	int err = 0;
254 	loff_t addr = (loff_t)ebnum * mtd->erasesize;
255 	size_t len = mtd->ecclayout->oobavail * pgcnt;
256 	size_t oobavail = mtd->ecclayout->oobavail;
257 	size_t bitflips;
258 	int i;
259 
260 	prandom_bytes_state(&rnd_state, writebuf, len);
261 	ops.mode      = MTD_OPS_AUTO_OOB;
262 	ops.len       = 0;
263 	ops.retlen    = 0;
264 	ops.ooblen    = len;
265 	ops.oobretlen = 0;
266 	ops.ooboffs   = 0;
267 	ops.datbuf    = NULL;
268 	ops.oobbuf    = readbuf;
269 
270 	/* read entire block's OOB at one go */
271 	err = mtd_read_oob(mtd, addr, &ops);
272 	if (err || ops.oobretlen != len) {
273 		pr_err("error: readoob failed at %#llx\n",
274 		       (long long)addr);
275 		errcnt += 1;
276 		return err ? err : -1;
277 	}
278 
279 	/* verify one page OOB at a time for bitflip per page limit check */
280 	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
281 		bitflips = memcmpshow(addr, readbuf + (i * oobavail),
282 				      writebuf + (i * oobavail), oobavail);
283 		if (bitflips > bitflip_limit) {
284 			pr_err("error: verify failed at %#llx\n",
285 			       (long long)addr);
286 			errcnt += 1;
287 			if (errcnt > 1000) {
288 				pr_err("error: too many errors\n");
289 				return -1;
290 			}
291 		} else if (bitflips) {
292 			pr_info("ignoring error as within bitflip_limit\n");
293 		}
294 	}
295 
296 	return err;
297 }
298 
299 static int verify_all_eraseblocks(void)
300 {
301 	int err;
302 	unsigned int i;
303 
304 	pr_info("verifying all eraseblocks\n");
305 	for (i = 0; i < ebcnt; ++i) {
306 		if (bbt[i])
307 			continue;
308 		err = verify_eraseblock(i);
309 		if (err)
310 			return err;
311 		if (i % 256 == 0)
312 			pr_info("verified up to eraseblock %u\n", i);
313 		cond_resched();
314 	}
315 	pr_info("verified %u eraseblocks\n", i);
316 	return 0;
317 }
318 
319 static int __init mtd_oobtest_init(void)
320 {
321 	int err = 0;
322 	unsigned int i;
323 	uint64_t tmp;
324 	struct mtd_oob_ops ops;
325 	loff_t addr = 0, addr0;
326 
327 	printk(KERN_INFO "\n");
328 	printk(KERN_INFO "=================================================\n");
329 
330 	if (dev < 0) {
331 		pr_info("Please specify a valid mtd-device via module parameter\n");
332 		pr_crit("CAREFUL: This test wipes all data on the specified MTD device!\n");
333 		return -EINVAL;
334 	}
335 
336 	pr_info("MTD device: %d\n", dev);
337 
338 	mtd = get_mtd_device(NULL, dev);
339 	if (IS_ERR(mtd)) {
340 		err = PTR_ERR(mtd);
341 		pr_err("error: cannot get MTD device\n");
342 		return err;
343 	}
344 
345 	if (!mtd_type_is_nand(mtd)) {
346 		pr_info("this test requires NAND flash\n");
347 		goto out;
348 	}
349 
350 	tmp = mtd->size;
351 	do_div(tmp, mtd->erasesize);
352 	ebcnt = tmp;
353 	pgcnt = mtd->erasesize / mtd->writesize;
354 
355 	pr_info("MTD device size %llu, eraseblock size %u, "
356 	       "page size %u, count of eraseblocks %u, pages per "
357 	       "eraseblock %u, OOB size %u\n",
358 	       (unsigned long long)mtd->size, mtd->erasesize,
359 	       mtd->writesize, ebcnt, pgcnt, mtd->oobsize);
360 
361 	err = -ENOMEM;
362 	readbuf = kmalloc(mtd->erasesize, GFP_KERNEL);
363 	if (!readbuf)
364 		goto out;
365 	writebuf = kmalloc(mtd->erasesize, GFP_KERNEL);
366 	if (!writebuf)
367 		goto out;
368 	bbt = kzalloc(ebcnt, GFP_KERNEL);
369 	if (!bbt)
370 		goto out;
371 
372 	err = mtdtest_scan_for_bad_eraseblocks(mtd, bbt, 0, ebcnt);
373 	if (err)
374 		goto out;
375 
376 	use_offset = 0;
377 	use_len = mtd->ecclayout->oobavail;
378 	use_len_max = mtd->ecclayout->oobavail;
379 	vary_offset = 0;
380 
381 	/* First test: write all OOB, read it back and verify */
382 	pr_info("test 1 of 5\n");
383 
384 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
385 	if (err)
386 		goto out;
387 
388 	prandom_seed_state(&rnd_state, 1);
389 	err = write_whole_device();
390 	if (err)
391 		goto out;
392 
393 	prandom_seed_state(&rnd_state, 1);
394 	err = verify_all_eraseblocks();
395 	if (err)
396 		goto out;
397 
398 	/*
399 	 * Second test: write all OOB, a block at a time, read it back and
400 	 * verify.
401 	 */
402 	pr_info("test 2 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, 3);
409 	err = write_whole_device();
410 	if (err)
411 		goto out;
412 
413 	/* Check all eraseblocks */
414 	prandom_seed_state(&rnd_state, 3);
415 	pr_info("verifying all eraseblocks\n");
416 	for (i = 0; i < ebcnt; ++i) {
417 		if (bbt[i])
418 			continue;
419 		err = verify_eraseblock_in_one_go(i);
420 		if (err)
421 			goto out;
422 		if (i % 256 == 0)
423 			pr_info("verified up to eraseblock %u\n", i);
424 		cond_resched();
425 	}
426 	pr_info("verified %u eraseblocks\n", i);
427 
428 	/*
429 	 * Third test: write OOB at varying offsets and lengths, read it back
430 	 * and verify.
431 	 */
432 	pr_info("test 3 of 5\n");
433 
434 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
435 	if (err)
436 		goto out;
437 
438 	/* Write all eraseblocks */
439 	use_offset = 0;
440 	use_len = mtd->ecclayout->oobavail;
441 	use_len_max = mtd->ecclayout->oobavail;
442 	vary_offset = 1;
443 	prandom_seed_state(&rnd_state, 5);
444 
445 	err = write_whole_device();
446 	if (err)
447 		goto out;
448 
449 	/* Check all eraseblocks */
450 	use_offset = 0;
451 	use_len = mtd->ecclayout->oobavail;
452 	use_len_max = mtd->ecclayout->oobavail;
453 	vary_offset = 1;
454 	prandom_seed_state(&rnd_state, 5);
455 	err = verify_all_eraseblocks();
456 	if (err)
457 		goto out;
458 
459 	use_offset = 0;
460 	use_len = mtd->ecclayout->oobavail;
461 	use_len_max = mtd->ecclayout->oobavail;
462 	vary_offset = 0;
463 
464 	/* Fourth test: try to write off end of device */
465 	pr_info("test 4 of 5\n");
466 
467 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
468 	if (err)
469 		goto out;
470 
471 	addr0 = 0;
472 	for (i = 0; i < ebcnt && bbt[i]; ++i)
473 		addr0 += mtd->erasesize;
474 
475 	/* Attempt to write off end of OOB */
476 	ops.mode      = MTD_OPS_AUTO_OOB;
477 	ops.len       = 0;
478 	ops.retlen    = 0;
479 	ops.ooblen    = 1;
480 	ops.oobretlen = 0;
481 	ops.ooboffs   = mtd->ecclayout->oobavail;
482 	ops.datbuf    = NULL;
483 	ops.oobbuf    = writebuf;
484 	pr_info("attempting to start write past end of OOB\n");
485 	pr_info("an error is expected...\n");
486 	err = mtd_write_oob(mtd, addr0, &ops);
487 	if (err) {
488 		pr_info("error occurred as expected\n");
489 		err = 0;
490 	} else {
491 		pr_err("error: can write past end of OOB\n");
492 		errcnt += 1;
493 	}
494 
495 	/* Attempt to read 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->ecclayout->oobavail;
502 	ops.datbuf    = NULL;
503 	ops.oobbuf    = readbuf;
504 	pr_info("attempting to start read past end of OOB\n");
505 	pr_info("an error is expected...\n");
506 	err = mtd_read_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 read past end of OOB\n");
512 		errcnt += 1;
513 	}
514 
515 	if (bbt[ebcnt - 1])
516 		pr_info("skipping end of device tests because last "
517 		       "block is bad\n");
518 	else {
519 		/* Attempt to write off end of device */
520 		ops.mode      = MTD_OPS_AUTO_OOB;
521 		ops.len       = 0;
522 		ops.retlen    = 0;
523 		ops.ooblen    = mtd->ecclayout->oobavail + 1;
524 		ops.oobretlen = 0;
525 		ops.ooboffs   = 0;
526 		ops.datbuf    = NULL;
527 		ops.oobbuf    = writebuf;
528 		pr_info("attempting to write past end of device\n");
529 		pr_info("an error is expected...\n");
530 		err = mtd_write_oob(mtd, mtd->size - mtd->writesize, &ops);
531 		if (err) {
532 			pr_info("error occurred as expected\n");
533 			err = 0;
534 		} else {
535 			pr_err("error: wrote past end of device\n");
536 			errcnt += 1;
537 		}
538 
539 		/* Attempt to read off end of device */
540 		ops.mode      = MTD_OPS_AUTO_OOB;
541 		ops.len       = 0;
542 		ops.retlen    = 0;
543 		ops.ooblen    = mtd->ecclayout->oobavail + 1;
544 		ops.oobretlen = 0;
545 		ops.ooboffs   = 0;
546 		ops.datbuf    = NULL;
547 		ops.oobbuf    = readbuf;
548 		pr_info("attempting to read past end of device\n");
549 		pr_info("an error is expected...\n");
550 		err = mtd_read_oob(mtd, mtd->size - mtd->writesize, &ops);
551 		if (err) {
552 			pr_info("error occurred as expected\n");
553 			err = 0;
554 		} else {
555 			pr_err("error: read past end of device\n");
556 			errcnt += 1;
557 		}
558 
559 		err = mtdtest_erase_eraseblock(mtd, ebcnt - 1);
560 		if (err)
561 			goto out;
562 
563 		/* Attempt to write off end of device */
564 		ops.mode      = MTD_OPS_AUTO_OOB;
565 		ops.len       = 0;
566 		ops.retlen    = 0;
567 		ops.ooblen    = mtd->ecclayout->oobavail;
568 		ops.oobretlen = 0;
569 		ops.ooboffs   = 1;
570 		ops.datbuf    = NULL;
571 		ops.oobbuf    = writebuf;
572 		pr_info("attempting to write past end of device\n");
573 		pr_info("an error is expected...\n");
574 		err = mtd_write_oob(mtd, mtd->size - mtd->writesize, &ops);
575 		if (err) {
576 			pr_info("error occurred as expected\n");
577 			err = 0;
578 		} else {
579 			pr_err("error: wrote past end of device\n");
580 			errcnt += 1;
581 		}
582 
583 		/* Attempt to read off end of device */
584 		ops.mode      = MTD_OPS_AUTO_OOB;
585 		ops.len       = 0;
586 		ops.retlen    = 0;
587 		ops.ooblen    = mtd->ecclayout->oobavail;
588 		ops.oobretlen = 0;
589 		ops.ooboffs   = 1;
590 		ops.datbuf    = NULL;
591 		ops.oobbuf    = readbuf;
592 		pr_info("attempting to read past end of device\n");
593 		pr_info("an error is expected...\n");
594 		err = mtd_read_oob(mtd, mtd->size - mtd->writesize, &ops);
595 		if (err) {
596 			pr_info("error occurred as expected\n");
597 			err = 0;
598 		} else {
599 			pr_err("error: read past end of device\n");
600 			errcnt += 1;
601 		}
602 	}
603 
604 	/* Fifth test: write / read across block boundaries */
605 	pr_info("test 5 of 5\n");
606 
607 	/* Erase all eraseblocks */
608 	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
609 	if (err)
610 		goto out;
611 
612 	/* Write all eraseblocks */
613 	prandom_seed_state(&rnd_state, 11);
614 	pr_info("writing OOBs of whole device\n");
615 	for (i = 0; i < ebcnt - 1; ++i) {
616 		int cnt = 2;
617 		int pg;
618 		size_t sz = mtd->ecclayout->oobavail;
619 		if (bbt[i] || bbt[i + 1])
620 			continue;
621 		addr = (loff_t)(i + 1) * mtd->erasesize - mtd->writesize;
622 		prandom_bytes_state(&rnd_state, writebuf, sz * cnt);
623 		for (pg = 0; pg < cnt; ++pg) {
624 			ops.mode      = MTD_OPS_AUTO_OOB;
625 			ops.len       = 0;
626 			ops.retlen    = 0;
627 			ops.ooblen    = sz;
628 			ops.oobretlen = 0;
629 			ops.ooboffs   = 0;
630 			ops.datbuf    = NULL;
631 			ops.oobbuf    = writebuf + pg * sz;
632 			err = mtd_write_oob(mtd, addr, &ops);
633 			if (err)
634 				goto out;
635 			if (i % 256 == 0)
636 				pr_info("written up to eraseblock %u\n", i);
637 			cond_resched();
638 			addr += mtd->writesize;
639 		}
640 	}
641 	pr_info("written %u eraseblocks\n", i);
642 
643 	/* Check all eraseblocks */
644 	prandom_seed_state(&rnd_state, 11);
645 	pr_info("verifying all eraseblocks\n");
646 	for (i = 0; i < ebcnt - 1; ++i) {
647 		if (bbt[i] || bbt[i + 1])
648 			continue;
649 		prandom_bytes_state(&rnd_state, writebuf,
650 					mtd->ecclayout->oobavail * 2);
651 		addr = (loff_t)(i + 1) * mtd->erasesize - mtd->writesize;
652 		ops.mode      = MTD_OPS_AUTO_OOB;
653 		ops.len       = 0;
654 		ops.retlen    = 0;
655 		ops.ooblen    = mtd->ecclayout->oobavail * 2;
656 		ops.oobretlen = 0;
657 		ops.ooboffs   = 0;
658 		ops.datbuf    = NULL;
659 		ops.oobbuf    = readbuf;
660 		err = mtd_read_oob(mtd, addr, &ops);
661 		if (err)
662 			goto out;
663 		if (memcmpshow(addr, readbuf, writebuf,
664 			       mtd->ecclayout->oobavail * 2)) {
665 			pr_err("error: verify failed at %#llx\n",
666 			       (long long)addr);
667 			errcnt += 1;
668 			if (errcnt > 1000) {
669 				pr_err("error: too many errors\n");
670 				goto out;
671 			}
672 		}
673 		if (i % 256 == 0)
674 			pr_info("verified up to eraseblock %u\n", i);
675 		cond_resched();
676 	}
677 	pr_info("verified %u eraseblocks\n", i);
678 
679 	pr_info("finished with %d errors\n", errcnt);
680 out:
681 	kfree(bbt);
682 	kfree(writebuf);
683 	kfree(readbuf);
684 	put_mtd_device(mtd);
685 	if (err)
686 		pr_info("error %d occurred\n", err);
687 	printk(KERN_INFO "=================================================\n");
688 	return err;
689 }
690 module_init(mtd_oobtest_init);
691 
692 static void __exit mtd_oobtest_exit(void)
693 {
694 	return;
695 }
696 module_exit(mtd_oobtest_exit);
697 
698 MODULE_DESCRIPTION("Out-of-band test module");
699 MODULE_AUTHOR("Adrian Hunter");
700 MODULE_LICENSE("GPL");
701