kernel/drivers/mtd/tests/oobtest.c

   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");