summaryrefslogtreecommitdiff
path: root/drivers/mtd/tests/mtd_oobtest.c
blob: ed9b62827f1bee15e6f5236e4c47f92cae6bfd5c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
/*
 * Copyright (C) 2006-2008 Nokia Corporation
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; see the file COPYING. If not, write to the Free Software
 * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Test OOB read and write on MTD device.
 *
 * Author: Adrian Hunter <ext-adrian.hunter@nokia.com>
 */

#include <asm/div64.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/err.h>
#include <linux/mtd/mtd.h>
#include <linux/slab.h>
#include <linux/sched.h>

#define PRINT_PREF KERN_INFO "mtd_oobtest: "

static int dev = -EINVAL;
module_param(dev, int, S_IRUGO);
MODULE_PARM_DESC(dev, "MTD device number to use");

static struct mtd_info *mtd;
static unsigned char *readbuf;
static unsigned char *writebuf;
static unsigned char *bbt;

static int ebcnt;
static int pgcnt;
static int errcnt;
static int use_offset;
static int use_len;
static int use_len_max;
static int vary_offset;
static unsigned long next = 1;

static inline unsigned int simple_rand(void)
{
	next = next * 1103515245 + 12345;
	return (unsigned int)((next / 65536) % 32768);
}

static inline void simple_srand(unsigned long seed)
{
	next = seed;
}

static void set_random_data(unsigned char *buf, size_t len)
{
	size_t i;

	for (i = 0; i < len; ++i)
		buf[i] = simple_rand();
}

static int erase_eraseblock(int ebnum)
{
	int err;
	struct erase_info ei;
	loff_t addr = ebnum * mtd->erasesize;

	memset(&ei, 0, sizeof(struct erase_info));
	ei.mtd  = mtd;
	ei.addr = addr;
	ei.len  = mtd->erasesize;

	err = mtd_erase(mtd, &ei);
	if (err) {
		printk(PRINT_PREF "error %d while erasing EB %d\n", err, ebnum);
		return err;
	}

	if (ei.state == MTD_ERASE_FAILED) {
		printk(PRINT_PREF "some erase error occurred at EB %d\n",
		       ebnum);
		return -EIO;
	}

	return 0;
}

static int erase_whole_device(void)
{
	int err;
	unsigned int i;

	printk(PRINT_PREF "erasing whole device\n");
	for (i = 0; i < ebcnt; ++i) {
		if (bbt[i])
			continue;
		err = erase_eraseblock(i);
		if (err)
			return err;
		cond_resched();
	}
	printk(PRINT_PREF "erased %u eraseblocks\n", i);
	return 0;
}

static void do_vary_offset(void)
{
	use_len -= 1;
	if (use_len < 1) {
		use_offset += 1;
		if (use_offset >= use_len_max)
			use_offset = 0;
		use_len = use_len_max - use_offset;
	}
}

static int write_eraseblock(int ebnum)
{
	int i;
	struct mtd_oob_ops ops;
	int err = 0;
	loff_t addr = ebnum * mtd->erasesize;

	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
		set_random_data(writebuf, use_len);
		ops.mode      = MTD_OPS_AUTO_OOB;
		ops.len       = 0;
		ops.retlen    = 0;
		ops.ooblen    = use_len;
		ops.oobretlen = 0;
		ops.ooboffs   = use_offset;
		ops.datbuf    = NULL;
		ops.oobbuf    = writebuf;
		err = mtd_write_oob(mtd, addr, &ops);
		if (err || ops.oobretlen != use_len) {
			printk(PRINT_PREF "error: writeoob failed at %#llx\n",
			       (long long)addr);
			printk(PRINT_PREF "error: use_len %d, use_offset %d\n",
			       use_len, use_offset);
			errcnt += 1;
			return err ? err : -1;
		}
		if (vary_offset)
			do_vary_offset();
	}

	return err;
}

static int write_whole_device(void)
{
	int err;
	unsigned int i;

	printk(PRINT_PREF "writing OOBs of whole device\n");
	for (i = 0; i < ebcnt; ++i) {
		if (bbt[i])
			continue;
		err = write_eraseblock(i);
		if (err)
			return err;
		if (i % 256 == 0)
			printk(PRINT_PREF "written up to eraseblock %u\n", i);
		cond_resched();
	}
	printk(PRINT_PREF "written %u eraseblocks\n", i);
	return 0;
}

static int verify_eraseblock(int ebnum)
{
	int i;
	struct mtd_oob_ops ops;
	int err = 0;
	loff_t addr = ebnum * mtd->erasesize;

	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
		set_random_data(writebuf, use_len);
		ops.mode      = MTD_OPS_AUTO_OOB;
		ops.len       = 0;
		ops.retlen    = 0;
		ops.ooblen    = use_len;
		ops.oobretlen = 0;
		ops.ooboffs   = use_offset;
		ops.datbuf    = NULL;
		ops.oobbuf    = readbuf;
		err = mtd_read_oob(mtd, addr, &ops);
		if (err || ops.oobretlen != use_len) {
			printk(PRINT_PREF "error: readoob failed at %#llx\n",
			       (long long)addr);
			errcnt += 1;
			return err ? err : -1;
		}
		if (memcmp(readbuf, writebuf, use_len)) {
			printk(PRINT_PREF "error: verify failed at %#llx\n",
			       (long long)addr);
			errcnt += 1;
			if (errcnt > 1000) {
				printk(PRINT_PREF "error: too many errors\n");
				return -1;
			}
		}
		if (use_offset != 0 || use_len < mtd->ecclayout->oobavail) {
			int k;

			ops.mode      = MTD_OPS_AUTO_OOB;
			ops.len       = 0;
			ops.retlen    = 0;
			ops.ooblen    = mtd->ecclayout->oobavail;
			ops.oobretlen = 0;
			ops.ooboffs   = 0;
			ops.datbuf    = NULL;
			ops.oobbuf    = readbuf;
			err = mtd_read_oob(mtd, addr, &ops);
			if (err || ops.oobretlen != mtd->ecclayout->oobavail) {
				printk(PRINT_PREF "error: readoob failed at "
				       "%#llx\n", (long long)addr);
				errcnt += 1;
				return err ? err : -1;
			}
			if (memcmp(readbuf + use_offset, writebuf, use_len)) {
				printk(PRINT_PREF "error: verify failed at "
				       "%#llx\n", (long long)addr);
				errcnt += 1;
				if (errcnt > 1000) {
					printk(PRINT_PREF "error: too many "
					       "errors\n");
					return -1;
				}
			}
			for (k = 0; k < use_offset; ++k)
				if (readbuf[k] != 0xff) {
					printk(PRINT_PREF "error: verify 0xff "
					       "failed at %#llx\n",
					       (long long)addr);
					errcnt += 1;
					if (errcnt > 1000) {
						printk(PRINT_PREF "error: too "
						       "many errors\n");
						return -1;
					}
				}
			for (k = use_offset + use_len;
			     k < mtd->ecclayout->oobavail; ++k)
				if (readbuf[k] != 0xff) {
					printk(PRINT_PREF "error: verify 0xff "
					       "failed at %#llx\n",
					       (long long)addr);
					errcnt += 1;
					if (errcnt > 1000) {
						printk(PRINT_PREF "error: too "
						       "many errors\n");
						return -1;
					}
				}
		}
		if (vary_offset)
			do_vary_offset();
	}
	return err;
}

static int verify_eraseblock_in_one_go(int ebnum)
{
	struct mtd_oob_ops ops;
	int err = 0;
	loff_t addr = ebnum * mtd->erasesize;
	size_t len = mtd->ecclayout->oobavail * pgcnt;

	set_random_data(writebuf, len);
	ops.mode      = MTD_OPS_AUTO_OOB;
	ops.len       = 0;
	ops.retlen    = 0;
	ops.ooblen    = len;
	ops.oobretlen = 0;
	ops.ooboffs   = 0;
	ops.datbuf    = NULL;
	ops.oobbuf    = readbuf;
	err = mtd_read_oob(mtd, addr, &ops);
	if (err || ops.oobretlen != len) {
		printk(PRINT_PREF "error: readoob failed at %#llx\n",
		       (long long)addr);
		errcnt += 1;
		return err ? err : -1;
	}
	if (memcmp(readbuf, writebuf, len)) {
		printk(PRINT_PREF "error: verify failed at %#llx\n",
		       (long long)addr);
		errcnt += 1;
		if (errcnt > 1000) {
			printk(PRINT_PREF "error: too many errors\n");
			return -1;
		}
	}

	return err;
}

static int verify_all_eraseblocks(void)
{
	int err;
	unsigned int i;

	printk(PRINT_PREF "verifying all eraseblocks\n");
	for (i = 0; i < ebcnt; ++i) {
		if (bbt[i])
			continue;
		err = verify_eraseblock(i);
		if (err)
			return err;
		if (i % 256 == 0)
			printk(PRINT_PREF "verified up to eraseblock %u\n", i);
		cond_resched();
	}
	printk(PRINT_PREF "verified %u eraseblocks\n", i);
	return 0;
}

static int is_block_bad(int ebnum)
{
	int ret;
	loff_t addr = ebnum * mtd->erasesize;

	ret = mtd_block_isbad(mtd, addr);
	if (ret)
		printk(PRINT_PREF "block %d is bad\n", ebnum);
	return ret;
}

static int scan_for_bad_eraseblocks(void)
{
	int i, bad = 0;

	bbt = kmalloc(ebcnt, GFP_KERNEL);
	if (!bbt) {
		printk(PRINT_PREF "error: cannot allocate memory\n");
		return -ENOMEM;
	}

	printk(PRINT_PREF "scanning for bad eraseblocks\n");
	for (i = 0; i < ebcnt; ++i) {
		bbt[i] = is_block_bad(i) ? 1 : 0;
		if (bbt[i])
			bad += 1;
		cond_resched();
	}
	printk(PRINT_PREF "scanned %d eraseblocks, %d are bad\n", i, bad);
	return 0;
}

static int __init mtd_oobtest_init(void)
{
	int err = 0;
	unsigned int i;
	uint64_t tmp;
	struct mtd_oob_ops ops;
	loff_t addr = 0, addr0;

	printk(KERN_INFO "\n");
	printk(KERN_INFO "=================================================\n");

	if (dev < 0) {
		printk(PRINT_PREF "Please specify a valid mtd-device via module paramter\n");
		printk(KERN_CRIT "CAREFUL: This test wipes all data on the specified MTD device!\n");
		return -EINVAL;
	}

	printk(PRINT_PREF "MTD device: %d\n", dev);

	mtd = get_mtd_device(NULL, dev);
	if (IS_ERR(mtd)) {
		err = PTR_ERR(mtd);
		printk(PRINT_PREF "error: cannot get MTD device\n");
		return err;
	}

	if (mtd->type != MTD_NANDFLASH) {
		printk(PRINT_PREF "this test requires NAND flash\n");
		goto out;
	}

	tmp = mtd->size;
	do_div(tmp, mtd->erasesize);
	ebcnt = tmp;
	pgcnt = mtd->erasesize / mtd->writesize;

	printk(PRINT_PREF "MTD device size %llu, eraseblock size %u, "
	       "page size %u, count of eraseblocks %u, pages per "
	       "eraseblock %u, OOB size %u\n",
	       (unsigned long long)mtd->size, mtd->erasesize,
	       mtd->writesize, ebcnt, pgcnt, mtd->oobsize);

	err = -ENOMEM;
	readbuf = kmalloc(mtd->erasesize, GFP_KERNEL);
	if (!readbuf) {
		printk(PRINT_PREF "error: cannot allocate memory\n");
		goto out;
	}
	writebuf = kmalloc(mtd->erasesize, GFP_KERNEL);
	if (!writebuf) {
		printk(PRINT_PREF "error: cannot allocate memory\n");
		goto out;
	}

	err = scan_for_bad_eraseblocks();
	if (err)
		goto out;

	use_offset = 0;
	use_len = mtd->ecclayout->oobavail;
	use_len_max = mtd->ecclayout->oobavail;
	vary_offset = 0;

	/* First test: write all OOB, read it back and verify */
	printk(PRINT_PREF "test 1 of 5\n");

	err = erase_whole_device();
	if (err)
		goto out;

	simple_srand(1);
	err = write_whole_device();
	if (err)
		goto out;

	simple_srand(1);
	err = verify_all_eraseblocks();
	if (err)
		goto out;

	/*
	 * Second test: write all OOB, a block at a time, read it back and
	 * verify.
	 */
	printk(PRINT_PREF "test 2 of 5\n");

	err = erase_whole_device();
	if (err)
		goto out;

	simple_srand(3);
	err = write_whole_device();
	if (err)
		goto out;

	/* Check all eraseblocks */
	simple_srand(3);
	printk(PRINT_PREF "verifying all eraseblocks\n");
	for (i = 0; i < ebcnt; ++i) {
		if (bbt[i])
			continue;
		err = verify_eraseblock_in_one_go(i);
		if (err)
			goto out;
		if (i % 256 == 0)
			printk(PRINT_PREF "verified up to eraseblock %u\n", i);
		cond_resched();
	}
	printk(PRINT_PREF "verified %u eraseblocks\n", i);

	/*
	 * Third test: write OOB at varying offsets and lengths, read it back
	 * and verify.
	 */
	printk(PRINT_PREF "test 3 of 5\n");

	err = erase_whole_device();
	if (err)
		goto out;

	/* Write all eraseblocks */
	use_offset = 0;
	use_len = mtd->ecclayout->oobavail;
	use_len_max = mtd->ecclayout->oobavail;
	vary_offset = 1;
	simple_srand(5);

	err = write_whole_device();
	if (err)
		goto out;

	/* Check all eraseblocks */
	use_offset = 0;
	use_len = mtd->ecclayout->oobavail;
	use_len_max = mtd->ecclayout->oobavail;
	vary_offset = 1;
	simple_srand(5);
	err = verify_all_eraseblocks();
	if (err)
		goto out;

	use_offset = 0;
	use_len = mtd->ecclayout->oobavail;
	use_len_max = mtd->ecclayout->oobavail;
	vary_offset = 0;

	/* Fourth test: try to write off end of device */
	printk(PRINT_PREF "test 4 of 5\n");

	err = erase_whole_device();
	if (err)
		goto out;

	addr0 = 0;
	for (i = 0; i < ebcnt && bbt[i]; ++i)
		addr0 += mtd->erasesize;

	/* Attempt to write off end of OOB */
	ops.mode      = MTD_OPS_AUTO_OOB;
	ops.len       = 0;
	ops.retlen    = 0;
	ops.ooblen    = 1;
	ops.oobretlen = 0;
	ops.ooboffs   = mtd->ecclayout->oobavail;
	ops.datbuf    = NULL;
	ops.oobbuf    = writebuf;
	printk(PRINT_PREF "attempting to start write past end of OOB\n");
	printk(PRINT_PREF "an error is expected...\n");
	err = mtd_write_oob(mtd, addr0, &ops);
	if (err) {
		printk(PRINT_PREF "error occurred as expected\n");
		err = 0;
	} else {
		printk(PRINT_PREF "error: can write past end of OOB\n");
		errcnt += 1;
	}

	/* Attempt to read off end of OOB */
	ops.mode      = MTD_OPS_AUTO_OOB;
	ops.len       = 0;
	ops.retlen    = 0;
	ops.ooblen    = 1;
	ops.oobretlen = 0;
	ops.ooboffs   = mtd->ecclayout->oobavail;
	ops.datbuf    = NULL;
	ops.oobbuf    = readbuf;
	printk(PRINT_PREF "attempting to start read past end of OOB\n");
	printk(PRINT_PREF "an error is expected...\n");
	err = mtd_read_oob(mtd, addr0, &ops);
	if (err) {
		printk(PRINT_PREF "error occurred as expected\n");
		err = 0;
	} else {
		printk(PRINT_PREF "error: can read past end of OOB\n");
		errcnt += 1;
	}

	if (bbt[ebcnt - 1])
		printk(PRINT_PREF "skipping end of device tests because last "
		       "block is bad\n");
	else {
		/* Attempt to write off end of device */
		ops.mode      = MTD_OPS_AUTO_OOB;
		ops.len       = 0;
		ops.retlen    = 0;
		ops.ooblen    = mtd->ecclayout->oobavail + 1;
		ops.oobretlen = 0;
		ops.ooboffs   = 0;
		ops.datbuf    = NULL;
		ops.oobbuf    = writebuf;
		printk(PRINT_PREF "attempting to write past end of device\n");
		printk(PRINT_PREF "an error is expected...\n");
		err = mtd_write_oob(mtd, mtd->size - mtd->writesize, &ops);
		if (err) {
			printk(PRINT_PREF "error occurred as expected\n");
			err = 0;
		} else {
			printk(PRINT_PREF "error: wrote past end of device\n");
			errcnt += 1;
		}

		/* Attempt to read off end of device */
		ops.mode      = MTD_OPS_AUTO_OOB;
		ops.len       = 0;
		ops.retlen    = 0;
		ops.ooblen    = mtd->ecclayout->oobavail + 1;
		ops.oobretlen = 0;
		ops.ooboffs   = 0;
		ops.datbuf    = NULL;
		ops.oobbuf    = readbuf;
		printk(PRINT_PREF "attempting to read past end of device\n");
		printk(PRINT_PREF "an error is expected...\n");
		err = mtd_read_oob(mtd, mtd->size - mtd->writesize, &ops);
		if (err) {
			printk(PRINT_PREF "error occurred as expected\n");
			err = 0;
		} else {
			printk(PRINT_PREF "error: read past end of device\n");
			errcnt += 1;
		}

		err = erase_eraseblock(ebcnt - 1);
		if (err)
			goto out;

		/* Attempt to write off end of device */
		ops.mode      = MTD_OPS_AUTO_OOB;
		ops.len       = 0;
		ops.retlen    = 0;
		ops.ooblen    = mtd->ecclayout->oobavail;
		ops.oobretlen = 0;
		ops.ooboffs   = 1;
		ops.datbuf    = NULL;
		ops.oobbuf    = writebuf;
		printk(PRINT_PREF "attempting to write past end of device\n");
		printk(PRINT_PREF "an error is expected...\n");
		err = mtd_write_oob(mtd, mtd->size - mtd->writesize, &ops);
		if (err) {
			printk(PRINT_PREF "error occurred as expected\n");
			err = 0;
		} else {
			printk(PRINT_PREF "error: wrote past end of device\n");
			errcnt += 1;
		}

		/* Attempt to read off end of device */
		ops.mode      = MTD_OPS_AUTO_OOB;
		ops.len       = 0;
		ops.retlen    = 0;
		ops.ooblen    = mtd->ecclayout->oobavail;
		ops.oobretlen = 0;
		ops.ooboffs   = 1;
		ops.datbuf    = NULL;
		ops.oobbuf    = readbuf;
		printk(PRINT_PREF "attempting to read past end of device\n");
		printk(PRINT_PREF "an error is expected...\n");
		err = mtd_read_oob(mtd, mtd->size - mtd->writesize, &ops);
		if (err) {
			printk(PRINT_PREF "error occurred as expected\n");
			err = 0;
		} else {
			printk(PRINT_PREF "error: read past end of device\n");
			errcnt += 1;
		}
	}

	/* Fifth test: write / read across block boundaries */
	printk(PRINT_PREF "test 5 of 5\n");

	/* Erase all eraseblocks */
	err = erase_whole_device();
	if (err)
		goto out;

	/* Write all eraseblocks */
	simple_srand(11);
	printk(PRINT_PREF "writing OOBs of whole device\n");
	for (i = 0; i < ebcnt - 1; ++i) {
		int cnt = 2;
		int pg;
		size_t sz = mtd->ecclayout->oobavail;
		if (bbt[i] || bbt[i + 1])
			continue;
		addr = (i + 1) * mtd->erasesize - mtd->writesize;
		for (pg = 0; pg < cnt; ++pg) {
			set_random_data(writebuf, sz);
			ops.mode      = MTD_OPS_AUTO_OOB;
			ops.len       = 0;
			ops.retlen    = 0;
			ops.ooblen    = sz;
			ops.oobretlen = 0;
			ops.ooboffs   = 0;
			ops.datbuf    = NULL;
			ops.oobbuf    = writebuf;
			err = mtd_write_oob(mtd, addr, &ops);
			if (err)
				goto out;
			if (i % 256 == 0)
				printk(PRINT_PREF "written up to eraseblock "
				       "%u\n", i);
			cond_resched();
			addr += mtd->writesize;
		}
	}
	printk(PRINT_PREF "written %u eraseblocks\n", i);

	/* Check all eraseblocks */
	simple_srand(11);
	printk(PRINT_PREF "verifying all eraseblocks\n");
	for (i = 0; i < ebcnt - 1; ++i) {
		if (bbt[i] || bbt[i + 1])
			continue;
		set_random_data(writebuf, mtd->ecclayout->oobavail * 2);
		addr = (i + 1) * mtd->erasesize - mtd->writesize;
		ops.mode      = MTD_OPS_AUTO_OOB;
		ops.len       = 0;
		ops.retlen    = 0;
		ops.ooblen    = mtd->ecclayout->oobavail * 2;
		ops.oobretlen = 0;
		ops.ooboffs   = 0;
		ops.datbuf    = NULL;
		ops.oobbuf    = readbuf;
		err = mtd_read_oob(mtd, addr, &ops);
		if (err)
			goto out;
		if (memcmp(readbuf, writebuf, mtd->ecclayout->oobavail * 2)) {
			printk(PRINT_PREF "error: verify failed at %#llx\n",
			       (long long)addr);
			errcnt += 1;
			if (errcnt > 1000) {
				printk(PRINT_PREF "error: too many errors\n");
				goto out;
			}
		}
		if (i % 256 == 0)
			printk(PRINT_PREF "verified up to eraseblock %u\n", i);
		cond_resched();
	}
	printk(PRINT_PREF "verified %u eraseblocks\n", i);

	printk(PRINT_PREF "finished with %d errors\n", errcnt);
out:
	kfree(bbt);
	kfree(writebuf);
	kfree(readbuf);
	put_mtd_device(mtd);
	if (err)
		printk(PRINT_PREF "error %d occurred\n", err);
	printk(KERN_INFO "=================================================\n");
	return err;
}
module_init(mtd_oobtest_init);

static void __exit mtd_oobtest_exit(void)
{
	return;
}
module_exit(mtd_oobtest_exit);

MODULE_DESCRIPTION("Out-of-band test module");
MODULE_AUTHOR("Adrian Hunter");
MODULE_LICENSE("GPL");