drivers/mtd/ubi/io.c

   1 /*
   2  * Copyright (c) International Business Machines Corp., 2006
   3  * Copyright (c) Nokia Corporation, 2006, 2007
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
  13  * the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  18  *
  19  * Author: Artem Bityutskiy (Битюцкий Артём)
  20  */
  21
  22 /*
  23  * UBI input/output unit.
  24  *
  25  * This unit provides a uniform way to work with all kinds of the underlying
  26  * MTD devices. It also implements handy functions for reading and writing UBI
  27  * headers.
  28  *
  29  * We are trying to have a paranoid mindset and not to trust to what we read
  30  * from the flash media in order to be more secure and robust. So this unit
  31  * validates every single header it reads from the flash media.
  32  *
  33  * Some words about how the eraseblock headers are stored.
  34  *
  35  * The erase counter header is always stored at offset zero. By default, the
  36  * VID header is stored after the EC header at the closest aligned offset
  37  * (i.e. aligned to the minimum I/O unit size). Data starts next to the VID
  38  * header at the closest aligned offset. But this default layout may be
  39  * changed. For example, for different reasons (e.g., optimization) UBI may be
  40  * asked to put the VID header at further offset, and even at an unaligned
  41  * offset. Of course, if the offset of the VID header is unaligned, UBI adds
  42  * proper padding in front of it. Data offset may also be changed but it has to
  43  * be aligned.
  44  *
  45  * About minimal I/O units. In general, UBI assumes flash device model where
  46  * there is only one minimal I/O unit size. E.g., in case of NOR flash it is 1,
  47  * in case of NAND flash it is a NAND page, etc. This is reported by MTD in the
  48  * @ubi->mtd->writesize field. But as an exception, UBI admits of using another
  49  * (smaller) minimal I/O unit size for EC and VID headers to make it possible
  50  * to do different optimizations.
  51  *
  52  * This is extremely useful in case of NAND flashes which admit of several
  53  * write operations to one NAND page. In this case UBI can fit EC and VID
  54  * headers at one NAND page. Thus, UBI may use "sub-page" size as the minimal
  55  * I/O unit for the headers (the @ubi->hdrs_min_io_size field). But it still
  56  * reports NAND page size (@ubi->min_io_size) as a minimal I/O unit for the UBI
  57  * users.
  58  *
  59  * Example: some Samsung NANDs with 2KiB pages allow 4x 512-byte writes, so
  60  * although the minimal I/O unit is 2K, UBI uses 512 bytes for EC and VID
  61  * headers.
  62  *
  63  * Q: why not just to treat sub-page as a minimal I/O unit of this flash
  64  * device, e.g., make @ubi->min_io_size = 512 in the example above?
  65  *
  66  * A: because when writing a sub-page, MTD still writes a full 2K page but the
  67  * bytes which are no relevant to the sub-page are 0xFF. So, basically, writing
  68  * 4x512 sub-pages is 4 times slower then writing one 2KiB NAND page. Thus, we
  69  * prefer to use sub-pages only for EV and VID headers.
  70  *
  71  * As it was noted above, the VID header may start at a non-aligned offset.
  72  * For example, in case of a 2KiB page NAND flash with a 512 bytes sub-page,
  73  * the VID header may reside at offset 1984 which is the last 64 bytes of the
  74  * last sub-page (EC header is always at offset zero). This causes some
  75  * difficulties when reading and writing VID headers.
  76  *
  77  * Suppose we have a 64-byte buffer and we read a VID header at it. We change
  78  * the data and want to write this VID header out. As we can only write in
  79  * 512-byte chunks, we have to allocate one more buffer and copy our VID header
  80  * to offset 448 of this buffer.
  81  *
  82  * The I/O unit does the following trick in order to avoid this extra copy.
  83  * It always allocates a @ubi->vid_hdr_alsize bytes buffer for the VID header
  84  * and returns a pointer to offset @ubi->vid_hdr_shift of this buffer. When the
  85  * VID header is being written out, it shifts the VID header pointer back and
  86  * writes the whole sub-page.
  87  */
  88
  89 #include <linux/crc32.h>
  90 #include <linux/err.h>
  91 #include "ubi.h"
  92
  93 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
  94 static int paranoid_check_not_bad(const struct ubi_device *ubi, int pnum);
  95 static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum);
  96 static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
  97                                  const struct ubi_ec_hdr *ec_hdr);
  98 static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum);
  99 static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
 100                                   const struct ubi_vid_hdr *vid_hdr);
 101 static int paranoid_check_all_ff(const struct ubi_device *ubi, int pnum,
 102                                  int offset, int len);
 103 #else
 104 #define paranoid_check_not_bad(ubi, pnum) 0
 105 #define paranoid_check_peb_ec_hdr(ubi, pnum)  0
 106 #define paranoid_check_ec_hdr(ubi, pnum, ec_hdr)  0
 107 #define paranoid_check_peb_vid_hdr(ubi, pnum) 0
 108 #define paranoid_check_vid_hdr(ubi, pnum, vid_hdr) 0
 109 #define paranoid_check_all_ff(ubi, pnum, offset, len) 0
 110 #endif
 111
 112 /**
 113  * ubi_io_read - read data from a physical eraseblock.
 114  * @ubi: UBI device description object
 115  * @buf: buffer where to store the read data
 116  * @pnum: physical eraseblock number to read from
 117  * @offset: offset within the physical eraseblock from where to read
 118  * @len: how many bytes to read
 119  *
 120  * This function reads data from offset @offset of physical eraseblock @pnum
 121  * and stores the read data in the @buf buffer. The following return codes are
 122  * possible:
 123  *
 124  * o %0 if all the requested data were successfully read;
 125  * o %UBI_IO_BITFLIPS if all the requested data were successfully read, but
 126  *   correctable bit-flips were detected; this is harmless but may indicate
 127  *   that this eraseblock may become bad soon (but do not have to);
 128  * o %-EBADMSG if the MTD subsystem reported about data data integrity
 129  *   problems, for example it can me an ECC error in case of NAND; this most
 130  *   probably means that the data is corrupted;
 131  * o %-EIO if some I/O error occurred;
 132  * o other negative error codes in case of other errors.
 133  */
 134 int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 135                 int len)
 136 {
 137         int err, retries = 0;
 138         size_t read;
 139         loff_t addr;
 140
 141         dbg_io("read %d bytes from PEB %d:%d", len, pnum, offset);
 142
 143         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 144         ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 145         ubi_assert(len > 0);
 146
 147         err = paranoid_check_not_bad(ubi, pnum);
 148         if (err)
 149                 return err > 0 ? -EINVAL : err;
 150
 151         addr = (loff_t)pnum * ubi->peb_size + offset;
 152 retry:
 153         err = ubi->mtd->read(ubi->mtd, addr, len, &read, buf);
 154         if (err) {
 155                 if (err == -EUCLEAN) {
 156                         /*
 157                          * -EUCLEAN is reported if there was a bit-flip which
 158                          * was corrected, so this is harmless.
 159                          */
 160                         ubi_msg("fixable bit-flip detected at PEB %d", pnum);
 161                         ubi_assert(len == read);
 162                         return UBI_IO_BITFLIPS;
 163                 }
 164
 165                 if (read != len && retries++ < UBI_IO_RETRIES) {
 166                         dbg_io("error %d while reading %d bytes from PEB %d:%d, "
 167                                "read only %zd bytes, retry",
 168                                err, len, pnum, offset, read);
 169                         yield();
 170                         goto retry;
 171                 }
 172
 173                 ubi_err("error %d while reading %d bytes from PEB %d:%d, "
 174                         "read %zd bytes", err, len, pnum, offset, read);
 175                 ubi_dbg_dump_stack();
 176         } else {
 177                 ubi_assert(len == read);
 178
 179                 if (ubi_dbg_is_bitflip()) {
 180                         dbg_msg("bit-flip (emulated)");
 181                         err = UBI_IO_BITFLIPS;
 182                 }
 183         }
 184
 185         return err;
 186 }
 187
 188 /**
 189  * ubi_io_write - write data to a physical eraseblock.
 190  * @ubi: UBI device description object
 191  * @buf: buffer with the data to write
 192  * @pnum: physical eraseblock number to write to
 193  * @offset: offset within the physical eraseblock where to write
 194  * @len: how many bytes to write
 195  *
 196  * This function writes @len bytes of data from buffer @buf to offset @offset
 197  * of physical eraseblock @pnum. If all the data were successfully written,
 198  * zero is returned. If an error occurred, this function returns a negative
 199  * error code. If %-EIO is returned, the physical eraseblock most probably went
 200  * bad.
 201  *
 202  * Note, in case of an error, it is possible that something was still written
 203  * to the flash media, but may be some garbage.
 204  */
 205 int ubi_io_write(const struct ubi_device *ubi, const void *buf, int pnum,
 206                  int offset, int len)
 207 {
 208         int err;
 209         size_t written;
 210         loff_t addr;
 211
 212         dbg_io("write %d bytes to PEB %d:%d", len, pnum, offset);
 213
 214         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 215         ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 216         ubi_assert(offset % ubi->hdrs_min_io_size == 0);
 217         ubi_assert(len > 0 && len % ubi->hdrs_min_io_size == 0);
 218
 219         if (ubi->ro_mode) {
 220                 ubi_err("read-only mode");
 221                 return -EROFS;
 222         }
 223
 224         /* The below has to be compiled out if paranoid checks are disabled */
 225
 226         err = paranoid_check_not_bad(ubi, pnum);
 227         if (err)
 228                 return err > 0 ? -EINVAL : err;
 229
 230         /* The area we are writing to has to contain all 0xFF bytes */
 231         err = paranoid_check_all_ff(ubi, pnum, offset, len);
 232         if (err)
 233                 return err > 0 ? -EINVAL : err;
 234
 235         if (offset >= ubi->leb_start) {
 236                 /*
 237                  * We write to the data area of the physical eraseblock. Make
 238                  * sure it has valid EC and VID headers.
 239                  */
 240                 err = paranoid_check_peb_ec_hdr(ubi, pnum);
 241                 if (err)
 242                         return err > 0 ? -EINVAL : err;
 243                 err = paranoid_check_peb_vid_hdr(ubi, pnum);
 244                 if (err)
 245                         return err > 0 ? -EINVAL : err;
 246         }
 247
 248         if (ubi_dbg_is_write_failure()) {
 249                 dbg_err("cannot write %d bytes to PEB %d:%d "
 250                         "(emulated)", len, pnum, offset);
 251                 ubi_dbg_dump_stack();
 252                 return -EIO;
 253         }
 254
 255         addr = (loff_t)pnum * ubi->peb_size + offset;
 256         err = ubi->mtd->write(ubi->mtd, addr, len, &written, buf);
 257         if (err) {
 258                 ubi_err("error %d while writing %d bytes to PEB %d:%d, written"
 259                         " %zd bytes", err, len, pnum, offset, written);
 260                 ubi_dbg_dump_stack();
 261         } else
 262                 ubi_assert(written == len);
 263
 264         return err;
 265 }
 266
 267 /**
 268  * erase_callback - MTD erasure call-back.
 269  * @ei: MTD erase information object.
 270  *
 271  * Note, even though MTD erase interface is asynchronous, all the current
 272  * implementations are synchronous anyway.
 273  */
 274 static void erase_callback(struct erase_info *ei)
 275 {
 276         wake_up_interruptible((wait_queue_head_t *)ei->priv);
 277 }
 278
 279 /**
 280  * do_sync_erase - synchronously erase a physical eraseblock.
 281  * @ubi: UBI device description object
 282  * @pnum: the physical eraseblock number to erase
 283  *
 284  * This function synchronously erases physical eraseblock @pnum and returns
 285  * zero in case of success and a negative error code in case of failure. If
 286  * %-EIO is returned, the physical eraseblock most probably went bad.
 287  */
 288 static int do_sync_erase(const struct ubi_device *ubi, int pnum)
 289 {
 290         int err, retries = 0;
 291         struct erase_info ei;
 292         wait_queue_head_t wq;
 293
 294         dbg_io("erase PEB %d", pnum);
 295
 296 retry:
 297         init_waitqueue_head(&wq);
 298         memset(&ei, 0, sizeof(struct erase_info));
 299
 300         ei.mtd      = ubi->mtd;
 301         ei.addr     = pnum * ubi->peb_size;
 302         ei.len      = ubi->peb_size;
 303         ei.callback = erase_callback;
 304         ei.priv     = (unsigned long)&wq;
 305
 306         err = ubi->mtd->erase(ubi->mtd, &ei);
 307         if (err) {
 308                 if (retries++ < UBI_IO_RETRIES) {
 309                         dbg_io("error %d while erasing PEB %d, retry",
 310                                err, pnum);
 311                         yield();
 312                         goto retry;
 313                 }
 314                 ubi_err("cannot erase PEB %d, error %d", pnum, err);
 315                 ubi_dbg_dump_stack();
 316                 return err;
 317         }
 318
 319         err = wait_event_interruptible(wq, ei.state == MTD_ERASE_DONE ||
 320                                            ei.state == MTD_ERASE_FAILED);
 321         if (err) {
 322                 ubi_err("interrupted PEB %d erasure", pnum);
 323                 return -EINTR;
 324         }
 325
 326         if (ei.state == MTD_ERASE_FAILED) {
 327                 if (retries++ < UBI_IO_RETRIES) {
 328                         dbg_io("error while erasing PEB %d, retry", pnum);
 329                         yield();
 330                         goto retry;
 331                 }
 332                 ubi_err("cannot erase PEB %d", pnum);
 333                 ubi_dbg_dump_stack();
 334                 return -EIO;
 335         }
 336
 337         err = paranoid_check_all_ff(ubi, pnum, 0, ubi->peb_size);
 338         if (err)
 339                 return err > 0 ? -EINVAL : err;
 340
 341         if (ubi_dbg_is_erase_failure() && !err) {
 342                 dbg_err("cannot erase PEB %d (emulated)", pnum);
 343                 return -EIO;
 344         }
 345
 346         return 0;
 347 }
 348
 349 /**
 350  * check_pattern - check if buffer contains only a certain byte pattern.
 351  * @buf: buffer to check
 352  * @patt: the pattern to check
 353  * @size: buffer size in bytes
 354  *
 355  * This function returns %1 in there are only @patt bytes in @buf, and %0 if
 356  * something else was also found.
 357  */
 358 static int check_pattern(const void *buf, uint8_t patt, int size)
 359 {
 360         int i;
 361
 362         for (i = 0; i < size; i++)
 363                 if (((const uint8_t *)buf)[i] != patt)
 364                         return 0;
 365         return 1;
 366 }
 367
 368 /* Patterns to write to a physical eraseblock when torturing it */
 369 static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
 370
 371 /**
 372  * torture_peb - test a supposedly bad physical eraseblock.
 373  * @ubi: UBI device description object
 374  * @pnum: the physical eraseblock number to test
 375  *
 376  * This function returns %-EIO if the physical eraseblock did not pass the
 377  * test, a positive number of erase operations done if the test was
 378  * successfully passed, and other negative error codes in case of other errors.
 379  */
 380 static int torture_peb(const struct ubi_device *ubi, int pnum)
 381 {
 382         void *buf;
 383         int err, i, patt_count;
 384
 385         buf = kmalloc(ubi->peb_size, GFP_KERNEL);
 386         if (!buf)
 387                 return -ENOMEM;
 388
 389         patt_count = ARRAY_SIZE(patterns);
 390         ubi_assert(patt_count > 0);
 391
 392         for (i = 0; i < patt_count; i++) {
 393                 err = do_sync_erase(ubi, pnum);
 394                 if (err)
 395                         goto out;
 396
 397                 /* Make sure the PEB contains only 0xFF bytes */
 398                 err = ubi_io_read(ubi, buf, pnum, 0, ubi->peb_size);
 399                 if (err)
 400                         goto out;
 401
 402                 err = check_pattern(buf, 0xFF, ubi->peb_size);
 403                 if (err == 0) {
 404                         ubi_err("erased PEB %d, but a non-0xFF byte found",
 405                                 pnum);
 406                         err = -EIO;
 407                         goto out;
 408                 }
 409
 410                 /* Write a pattern and check it */
 411                 memset(buf, patterns[i], ubi->peb_size);
 412                 err = ubi_io_write(ubi, buf, pnum, 0, ubi->peb_size);
 413                 if (err)
 414                         goto out;
 415
 416                 memset(buf, ~patterns[i], ubi->peb_size);
 417                 err = ubi_io_read(ubi, buf, pnum, 0, ubi->peb_size);
 418                 if (err)
 419                         goto out;
 420
 421                 err = check_pattern(buf, patterns[i], ubi->peb_size);
 422                 if (err == 0) {
 423                         ubi_err("pattern %x checking failed for PEB %d",
 424                                 patterns[i], pnum);
 425                         err = -EIO;
 426                         goto out;
 427                 }
 428         }
 429
 430         err = patt_count;
 431
 432 out:
 433         if (err == UBI_IO_BITFLIPS || err == -EBADMSG)
 434                 /*
 435                  * If a bit-flip or data integrity error was detected, the test
 436                  * has not passed because it happened on a freshly erased
 437                  * physical eraseblock which means something is wrong with it.
 438                  */
 439                 err = -EIO;
 440         kfree(buf);
 441         return err;
 442 }
 443
 444 /**
 445  * ubi_io_sync_erase - synchronously erase a physical eraseblock.
 446  * @ubi: UBI device description object
 447  * @pnum: physical eraseblock number to erase
 448  * @torture: if this physical eraseblock has to be tortured
 449  *
 450  * This function synchronously erases physical eraseblock @pnum. If @torture
 451  * flag is not zero, the physical eraseblock is checked by means of writing
 452  * different patterns to it and reading them back. If the torturing is enabled,
 453  * the physical eraseblock is erased more then once.
 454  *
 455  * This function returns the number of erasures made in case of success, %-EIO
 456  * if the erasure failed or the torturing test failed, and other negative error
 457  * codes in case of other errors. Note, %-EIO means that the physical
 458  * eraseblock is bad.
 459  */
 460 int ubi_io_sync_erase(const struct ubi_device *ubi, int pnum, int torture)
 461 {
 462         int err, ret = 0;
 463
 464         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 465
 466         err = paranoid_check_not_bad(ubi, pnum);
 467         if (err != 0)
 468                 return err > 0 ? -EINVAL : err;
 469
 470         if (ubi->ro_mode) {
 471                 ubi_err("read-only mode");
 472                 return -EROFS;
 473         }
 474
 475         if (torture) {
 476                 ret = torture_peb(ubi, pnum);
 477                 if (ret < 0)
 478                         return ret;
 479         }
 480
 481         err = do_sync_erase(ubi, pnum);
 482         if (err)
 483                 return err;
 484
 485         return ret + 1;
 486 }
 487
 488 /**
 489  * ubi_io_is_bad - check if a physical eraseblock is bad.
 490  * @ubi: UBI device description object
 491  * @pnum: the physical eraseblock number to check
 492  *
 493  * This function returns a positive number if the physical eraseblock is bad,
 494  * zero if not, and a negative error code if an error occurred.
 495  */
 496 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum)
 497 {
 498         struct mtd_info *mtd = ubi->mtd;
 499
 500         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 501
 502         if (ubi->bad_allowed) {
 503                 int ret;
 504
 505                 ret = mtd->block_isbad(mtd, (loff_t)pnum * ubi->peb_size);
 506                 if (ret < 0)
 507                         ubi_err("error %d while checking if PEB %d is bad",
 508                                 ret, pnum);
 509                 else if (ret)
 510                         dbg_io("PEB %d is bad", pnum);
 511                 return ret;
 512         }
 513
 514         return 0;
 515 }
 516
 517 /**
 518  * ubi_io_mark_bad - mark a physical eraseblock as bad.
 519  * @ubi: UBI device description object
 520  * @pnum: the physical eraseblock number to mark
 521  *
 522  * This function returns zero in case of success and a negative error code in
 523  * case of failure.
 524  */
 525 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
 526 {
 527         int err;
 528         struct mtd_info *mtd = ubi->mtd;
 529
 530         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 531
 532         if (ubi->ro_mode) {
 533                 ubi_err("read-only mode");
 534                 return -EROFS;
 535         }
 536
 537         if (!ubi->bad_allowed)
 538                 return 0;
 539
 540         err = mtd->block_markbad(mtd, (loff_t)pnum * ubi->peb_size);
 541         if (err)
 542                 ubi_err("cannot mark PEB %d bad, error %d", pnum, err);
 543         return err;
 544 }
 545
 546 /**
 547  * validate_ec_hdr - validate an erase counter header.
 548  * @ubi: UBI device description object
 549  * @ec_hdr: the erase counter header to check
 550  *
 551  * This function returns zero if the erase counter header is OK, and %1 if
 552  * not.
 553  */
 554 static int validate_ec_hdr(const struct ubi_device *ubi,
 555                            const struct ubi_ec_hdr *ec_hdr)
 556 {
 557         long long ec;
 558         int vid_hdr_offset, leb_start;
 559
 560         ec = ubi64_to_cpu(ec_hdr->ec);
 561         vid_hdr_offset = ubi32_to_cpu(ec_hdr->vid_hdr_offset);
 562         leb_start = ubi32_to_cpu(ec_hdr->data_offset);
 563
 564         if (ec_hdr->version != UBI_VERSION) {
 565                 ubi_err("node with incompatible UBI version found: "
 566                         "this UBI version is %d, image version is %d",
 567                         UBI_VERSION, (int)ec_hdr->version);
 568                 goto bad;
 569         }
 570
 571         if (vid_hdr_offset != ubi->vid_hdr_offset) {
 572                 ubi_err("bad VID header offset %d, expected %d",
 573                         vid_hdr_offset, ubi->vid_hdr_offset);
 574                 goto bad;
 575         }
 576
 577         if (leb_start != ubi->leb_start) {
 578                 ubi_err("bad data offset %d, expected %d",
 579                         leb_start, ubi->leb_start);
 580                 goto bad;
 581         }
 582
 583         if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
 584                 ubi_err("bad erase counter %lld", ec);
 585                 goto bad;
 586         }
 587
 588         return 0;
 589
 590 bad:
 591         ubi_err("bad EC header");
 592         ubi_dbg_dump_ec_hdr(ec_hdr);
 593         ubi_dbg_dump_stack();
 594         return 1;
 595 }
 596
 597 /**
 598  * ubi_io_read_ec_hdr - read and check an erase counter header.
 599  * @ubi: UBI device description object
 600  * @pnum: physical eraseblock to read from
 601  * @ec_hdr: a &struct ubi_ec_hdr object where to store the read erase counter
 602  * header
 603  * @verbose: be verbose if the header is corrupted or was not found
 604  *
 605  * This function reads erase counter header from physical eraseblock @pnum and
 606  * stores it in @ec_hdr. This function also checks CRC checksum of the read
 607  * erase counter header. The following codes may be returned:
 608  *
 609  * o %0 if the CRC checksum is correct and the header was successfully read;
 610  * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 611  *   and corrected by the flash driver; this is harmless but may indicate that
 612  *   this eraseblock may become bad soon (but may be not);
 613  * o %UBI_IO_BAD_EC_HDR if the erase counter header is corrupted (a CRC error);
 614  * o %UBI_IO_PEB_EMPTY if the physical eraseblock is empty;
 615  * o a negative error code in case of failure.
 616  */
 617 int ubi_io_read_ec_hdr(const struct ubi_device *ubi, int pnum,
 618                        struct ubi_ec_hdr *ec_hdr, int verbose)
 619 {
 620         int err, read_err = 0;
 621         uint32_t crc, magic, hdr_crc;
 622
 623         dbg_io("read EC header from PEB %d", pnum);
 624         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 625
 626         err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
 627         if (err) {
 628                 if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
 629                         return err;
 630
 631                 /*
 632                  * We read all the data, but either a correctable bit-flip
 633                  * occurred, or MTD reported about some data integrity error,
 634                  * like an ECC error in case of NAND. The former is harmless,
 635                  * the later may mean that the read data is corrupted. But we
 636                  * have a CRC check-sum and we will detect this. If the EC
 637                  * header is still OK, we just report this as there was a
 638                  * bit-flip.
 639                  */
 640                 read_err = err;
 641         }
 642
 643         magic = ubi32_to_cpu(ec_hdr->magic);
 644         if (magic != UBI_EC_HDR_MAGIC) {
 645                 /*
 646                  * The magic field is wrong. Let's check if we have read all
 647                  * 0xFF. If yes, this physical eraseblock is assumed to be
 648                  * empty.
 649                  *
 650                  * But if there was a read error, we do not test it for all
 651                  * 0xFFs. Even if it does contain all 0xFFs, this error
 652                  * indicates that something is still wrong with this physical
 653                  * eraseblock and we anyway cannot treat it as empty.
 654                  */
 655                 if (read_err != -EBADMSG &&
 656                     check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
 657                         /* The physical eraseblock is supposedly empty */
 658
 659                         /*
 660                          * The below is just a paranoid check, it has to be
 661                          * compiled out if paranoid checks are disabled.
 662                          */
 663                         err = paranoid_check_all_ff(ubi, pnum, 0,
 664                                                     ubi->peb_size);
 665                         if (err)
 666                                 return err > 0 ? UBI_IO_BAD_EC_HDR : err;
 667
 668                         if (verbose)
 669                                 ubi_warn("no EC header found at PEB %d, "
 670                                          "only 0xFF bytes", pnum);
 671                         return UBI_IO_PEB_EMPTY;
 672                 }
 673
 674                 /*
 675                  * This is not a valid erase counter header, and these are not
 676                  * 0xFF bytes. Report that the header is corrupted.
 677                  */
 678                 if (verbose) {
 679                         ubi_warn("bad magic number at PEB %d: %08x instead of "
 680                                  "%08x", pnum, magic, UBI_EC_HDR_MAGIC);
 681                         ubi_dbg_dump_ec_hdr(ec_hdr);
 682                 }
 683                 return UBI_IO_BAD_EC_HDR;
 684         }
 685
 686         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 687         hdr_crc = ubi32_to_cpu(ec_hdr->hdr_crc);
 688
 689         if (hdr_crc != crc) {
 690                 if (verbose) {
 691                         ubi_warn("bad EC header CRC at PEB %d, calculated %#08x,"
 692                                  " read %#08x", pnum, crc, hdr_crc);
 693                         ubi_dbg_dump_ec_hdr(ec_hdr);
 694                 }
 695                 return UBI_IO_BAD_EC_HDR;
 696         }
 697
 698         /* And of course validate what has just been read from the media */
 699         err = validate_ec_hdr(ubi, ec_hdr);
 700         if (err) {
 701                 ubi_err("validation failed for PEB %d", pnum);
 702                 return -EINVAL;
 703         }
 704
 705         return read_err ? UBI_IO_BITFLIPS : 0;
 706 }
 707
 708 /**
 709  * ubi_io_write_ec_hdr - write an erase counter header.
 710  * @ubi: UBI device description object
 711  * @pnum: physical eraseblock to write to
 712  * @ec_hdr: the erase counter header to write
 713  *
 714  * This function writes erase counter header described by @ec_hdr to physical
 715  * eraseblock @pnum. It also fills most fields of @ec_hdr before writing, so
 716  * the caller do not have to fill them. Callers must only fill the @ec_hdr->ec
 717  * field.
 718  *
 719  * This function returns zero in case of success and a negative error code in
 720  * case of failure. If %-EIO is returned, the physical eraseblock most probably
 721  * went bad.
 722  */
 723 int ubi_io_write_ec_hdr(const struct ubi_device *ubi, int pnum,
 724                         struct ubi_ec_hdr *ec_hdr)
 725 {
 726         int err;
 727         uint32_t crc;
 728
 729         dbg_io("write EC header to PEB %d", pnum);
 730         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 731
 732         ec_hdr->magic = cpu_to_ubi32(UBI_EC_HDR_MAGIC);
 733         ec_hdr->version = UBI_VERSION;
 734         ec_hdr->vid_hdr_offset = cpu_to_ubi32(ubi->vid_hdr_offset);
 735         ec_hdr->data_offset = cpu_to_ubi32(ubi->leb_start);
 736         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 737         ec_hdr->hdr_crc = cpu_to_ubi32(crc);
 738
 739         err = paranoid_check_ec_hdr(ubi, pnum, ec_hdr);
 740         if (err)
 741                 return -EINVAL;
 742
 743         err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
 744         return err;
 745 }
 746
 747 /**
 748  * validate_vid_hdr - validate a volume identifier header.
 749  * @ubi: UBI device description object
 750  * @vid_hdr: the volume identifier header to check
 751  *
 752  * This function checks that data stored in the volume identifier header
 753  * @vid_hdr. Returns zero if the VID header is OK and %1 if not.
 754  */
 755 static int validate_vid_hdr(const struct ubi_device *ubi,
 756                             const struct ubi_vid_hdr *vid_hdr)
 757 {
 758         int vol_type = vid_hdr->vol_type;
 759         int copy_flag = vid_hdr->copy_flag;
 760         int vol_id = ubi32_to_cpu(vid_hdr->vol_id);
 761         int lnum = ubi32_to_cpu(vid_hdr->lnum);
 762         int compat = vid_hdr->compat;
 763         int data_size = ubi32_to_cpu(vid_hdr->data_size);
 764         int used_ebs = ubi32_to_cpu(vid_hdr->used_ebs);
 765         int data_pad = ubi32_to_cpu(vid_hdr->data_pad);
 766         int data_crc = ubi32_to_cpu(vid_hdr->data_crc);
 767         int usable_leb_size = ubi->leb_size - data_pad;
 768
 769         if (copy_flag != 0 && copy_flag != 1) {
 770                 dbg_err("bad copy_flag");
 771                 goto bad;
 772         }
 773
 774         if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
 775             data_pad < 0) {
 776                 dbg_err("negative values");
 777                 goto bad;
 778         }
 779
 780         if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
 781                 dbg_err("bad vol_id");
 782                 goto bad;
 783         }
 784
 785         if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
 786                 dbg_err("bad compat");
 787                 goto bad;
 788         }
 789
 790         if (vol_id >= UBI_INTERNAL_VOL_START && compat != UBI_COMPAT_DELETE &&
 791             compat != UBI_COMPAT_RO && compat != UBI_COMPAT_PRESERVE &&
 792             compat != UBI_COMPAT_REJECT) {
 793                 dbg_err("bad compat");
 794                 goto bad;
 795         }
 796
 797         if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
 798                 dbg_err("bad vol_type");
 799                 goto bad;
 800         }
 801
 802         if (data_pad >= ubi->leb_size / 2) {
 803                 dbg_err("bad data_pad");
 804                 goto bad;
 805         }
 806
 807         if (vol_type == UBI_VID_STATIC) {
 808                 /*
 809                  * Although from high-level point of view static volumes may
 810                  * contain zero bytes of data, but no VID headers can contain
 811                  * zero at these fields, because they empty volumes do not have
 812                  * mapped logical eraseblocks.
 813                  */
 814                 if (used_ebs == 0) {
 815                         dbg_err("zero used_ebs");
 816                         goto bad;
 817                 }
 818                 if (data_size == 0) {
 819                         dbg_err("zero data_size");
 820                         goto bad;
 821                 }
 822                 if (lnum < used_ebs - 1) {
 823                         if (data_size != usable_leb_size) {
 824                                 dbg_err("bad data_size");
 825                                 goto bad;
 826                         }
 827                 } else if (lnum == used_ebs - 1) {
 828                         if (data_size == 0) {
 829                                 dbg_err("bad data_size at last LEB");
 830                                 goto bad;
 831                         }
 832                 } else {
 833                         dbg_err("too high lnum");
 834                         goto bad;
 835                 }
 836         } else {
 837                 if (copy_flag == 0) {
 838                         if (data_crc != 0) {
 839                                 dbg_err("non-zero data CRC");
 840                                 goto bad;
 841                         }
 842                         if (data_size != 0) {
 843                                 dbg_err("non-zero data_size");
 844                                 goto bad;
 845                         }
 846                 } else {
 847                         if (data_size == 0) {
 848                                 dbg_err("zero data_size of copy");
 849                                 goto bad;
 850                         }
 851                 }
 852                 if (used_ebs != 0) {
 853                         dbg_err("bad used_ebs");
 854                         goto bad;
 855                 }
 856         }
 857
 858         return 0;
 859
 860 bad:
 861         ubi_err("bad VID header");
 862         ubi_dbg_dump_vid_hdr(vid_hdr);
 863         ubi_dbg_dump_stack();
 864         return 1;
 865 }
 866
 867 /**
 868  * ubi_io_read_vid_hdr - read and check a volume identifier header.
 869  * @ubi: UBI device description object
 870  * @pnum: physical eraseblock number to read from
 871  * @vid_hdr: &struct ubi_vid_hdr object where to store the read volume
 872  * identifier header
 873  * @verbose: be verbose if the header is corrupted or wasn't found
 874  *
 875  * This function reads the volume identifier header from physical eraseblock
 876  * @pnum and stores it in @vid_hdr. It also checks CRC checksum of the read
 877  * volume identifier header. The following codes may be returned:
 878  *
 879  * o %0 if the CRC checksum is correct and the header was successfully read;
 880  * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 881  *   and corrected by the flash driver; this is harmless but may indicate that
 882  *   this eraseblock may become bad soon;
 883  * o %UBI_IO_BAD_VID_HRD if the volume identifier header is corrupted (a CRC
 884  *   error detected);
 885  * o %UBI_IO_PEB_FREE if the physical eraseblock is free (i.e., there is no VID
 886  *   header there);
 887  * o a negative error code in case of failure.
 888  */
 889 int ubi_io_read_vid_hdr(const struct ubi_device *ubi, int pnum,
 890                         struct ubi_vid_hdr *vid_hdr, int verbose)
 891 {
 892         int err, read_err = 0;
 893         uint32_t crc, magic, hdr_crc;
 894         void *p;
 895
 896         dbg_io("read VID header from PEB %d", pnum);
 897         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 898
 899         p = (char *)vid_hdr - ubi->vid_hdr_shift;
 900         err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
 901                           ubi->vid_hdr_alsize);
 902         if (err) {
 903                 if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
 904                         return err;
 905
 906                 /*
 907                  * We read all the data, but either a correctable bit-flip
 908                  * occurred, or MTD reported about some data integrity error,
 909                  * like an ECC error in case of NAND. The former is harmless,
 910                  * the later may mean the read data is corrupted. But we have a
 911                  * CRC check-sum and we will identify this. If the VID header is
 912                  * still OK, we just report this as there was a bit-flip.
 913                  */
 914                 read_err = err;
 915         }
 916
 917         magic = ubi32_to_cpu(vid_hdr->magic);
 918         if (magic != UBI_VID_HDR_MAGIC) {
 919                 /*
 920                  * If we have read all 0xFF bytes, the VID header probably does
 921                  * not exist and the physical eraseblock is assumed to be free.
 922                  *
 923                  * But if there was a read error, we do not test the data for
 924                  * 0xFFs. Even if it does contain all 0xFFs, this error
 925                  * indicates that something is still wrong with this physical
 926                  * eraseblock and it cannot be regarded as free.
 927                  */
 928                 if (read_err != -EBADMSG &&
 929                     check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
 930                         /* The physical eraseblock is supposedly free */
 931
 932                         /*
 933                          * The below is just a paranoid check, it has to be
 934                          * compiled out if paranoid checks are disabled.
 935                          */
 936                         err = paranoid_check_all_ff(ubi, pnum, ubi->leb_start,
 937                                                     ubi->leb_size);
 938                         if (err)
 939                                 return err > 0 ? UBI_IO_BAD_VID_HDR : err;
 940
 941                         if (verbose)
 942                                 ubi_warn("no VID header found at PEB %d, "
 943                                          "only 0xFF bytes", pnum);
 944                         return UBI_IO_PEB_FREE;
 945                 }
 946
 947                 /*
 948                  * This is not a valid VID header, and these are not 0xFF
 949                  * bytes. Report that the header is corrupted.
 950                  */
 951                 if (verbose) {
 952                         ubi_warn("bad magic number at PEB %d: %08x instead of "
 953                                  "%08x", pnum, magic, UBI_VID_HDR_MAGIC);
 954                         ubi_dbg_dump_vid_hdr(vid_hdr);
 955                 }
 956                 return UBI_IO_BAD_VID_HDR;
 957         }
 958
 959         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
 960         hdr_crc = ubi32_to_cpu(vid_hdr->hdr_crc);
 961
 962         if (hdr_crc != crc) {
 963                 if (verbose) {
 964                         ubi_warn("bad CRC at PEB %d, calculated %#08x, "
 965                                  "read %#08x", pnum, crc, hdr_crc);
 966                         ubi_dbg_dump_vid_hdr(vid_hdr);
 967                 }
 968                 return UBI_IO_BAD_VID_HDR;
 969         }
 970
 971         /* Validate the VID header that we have just read */
 972         err = validate_vid_hdr(ubi, vid_hdr);
 973         if (err) {
 974                 ubi_err("validation failed for PEB %d", pnum);
 975                 return -EINVAL;
 976         }
 977
 978         return read_err ? UBI_IO_BITFLIPS : 0;
 979 }
 980
 981 /**
 982  * ubi_io_write_vid_hdr - write a volume identifier header.
 983  * @ubi: UBI device description object
 984  * @pnum: the physical eraseblock number to write to
 985  * @vid_hdr: the volume identifier header to write
 986  *
 987  * This function writes the volume identifier header described by @vid_hdr to
 988  * physical eraseblock @pnum. This function automatically fills the
 989  * @vid_hdr->magic and the @vid_hdr->version fields, as well as calculates
 990  * header CRC checksum and stores it at vid_hdr->hdr_crc.
 991  *
 992  * This function returns zero in case of success and a negative error code in
 993  * case of failure. If %-EIO is returned, the physical eraseblock probably went
 994  * bad.
 995  */
 996 int ubi_io_write_vid_hdr(const struct ubi_device *ubi, int pnum,
 997                          struct ubi_vid_hdr *vid_hdr)
 998 {
 999         int err;
1000         uint32_t crc;
1001         void *p;
1002
1003         dbg_io("write VID header to PEB %d", pnum);
1004         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
1005
1006         err = paranoid_check_peb_ec_hdr(ubi, pnum);
1007         if (err)
1008                 return err > 0 ? -EINVAL: err;
1009
1010         vid_hdr->magic = cpu_to_ubi32(UBI_VID_HDR_MAGIC);
1011         vid_hdr->version = UBI_VERSION;
1012         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1013         vid_hdr->hdr_crc = cpu_to_ubi32(crc);
1014
1015         err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
1016         if (err)
1017                 return -EINVAL;
1018
1019         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1020         err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
1021                            ubi->vid_hdr_alsize);
1022         return err;
1023 }
1024
1025 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
1026
1027 /**
1028  * paranoid_check_not_bad - ensure that a physical eraseblock is not bad.
1029  * @ubi: UBI device description object
1030  * @pnum: physical eraseblock number to check
1031  *
1032  * This function returns zero if the physical eraseblock is good, a positive
1033  * number if it is bad and a negative error code if an error occurred.
1034  */
1035 static int paranoid_check_not_bad(const struct ubi_device *ubi, int pnum)
1036 {
1037         int err;
1038
1039         err = ubi_io_is_bad(ubi, pnum);
1040         if (!err)
1041                 return err;
1042
1043         ubi_err("paranoid check failed for PEB %d", pnum);
1044         ubi_dbg_dump_stack();
1045         return err;
1046 }
1047
1048 /**
1049  * paranoid_check_ec_hdr - check if an erase counter header is all right.
1050  * @ubi: UBI device description object
1051  * @pnum: physical eraseblock number the erase counter header belongs to
1052  * @ec_hdr: the erase counter header to check
1053  *
1054  * This function returns zero if the erase counter header contains valid
1055  * values, and %1 if not.
1056  */
1057 static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
1058                                  const struct ubi_ec_hdr *ec_hdr)
1059 {
1060         int err;
1061         uint32_t magic;
1062
1063         magic = ubi32_to_cpu(ec_hdr->magic);
1064         if (magic != UBI_EC_HDR_MAGIC) {
1065                 ubi_err("bad magic %#08x, must be %#08x",
1066                         magic, UBI_EC_HDR_MAGIC);
1067                 goto fail;
1068         }
1069
1070         err = validate_ec_hdr(ubi, ec_hdr);
1071         if (err) {
1072                 ubi_err("paranoid check failed for PEB %d", pnum);
1073                 goto fail;
1074         }
1075
1076         return 0;
1077
1078 fail:
1079         ubi_dbg_dump_ec_hdr(ec_hdr);
1080         ubi_dbg_dump_stack();
1081         return 1;
1082 }
1083
1084 /**
1085  * paranoid_check_peb_ec_hdr - check that the erase counter header of a
1086  * physical eraseblock is in-place and is all right.
1087  * @ubi: UBI device description object
1088  * @pnum: the physical eraseblock number to check
1089  *
1090  * This function returns zero if the erase counter header is all right, %1 if
1091  * not, and a negative error code if an error occurred.
1092  */
1093 static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
1094 {
1095         int err;
1096         uint32_t crc, hdr_crc;
1097         struct ubi_ec_hdr *ec_hdr;
1098
1099         ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
1100         if (!ec_hdr)
1101                 return -ENOMEM;
1102
1103         err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
1104         if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
1105                 goto exit;
1106
1107         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
1108         hdr_crc = ubi32_to_cpu(ec_hdr->hdr_crc);
1109         if (hdr_crc != crc) {
1110                 ubi_err("bad CRC, calculated %#08x, read %#08x", crc, hdr_crc);
1111                 ubi_err("paranoid check failed for PEB %d", pnum);
1112                 ubi_dbg_dump_ec_hdr(ec_hdr);
1113                 ubi_dbg_dump_stack();
1114                 err = 1;
1115                 goto exit;
1116         }
1117
1118         err = paranoid_check_ec_hdr(ubi, pnum, ec_hdr);
1119
1120 exit:
1121         kfree(ec_hdr);
1122         return err;
1123 }
1124
1125 /**
1126  * paranoid_check_vid_hdr - check that a volume identifier header is all right.
1127  * @ubi: UBI device description object
1128  * @pnum: physical eraseblock number the volume identifier header belongs to
1129  * @vid_hdr: the volume identifier header to check
1130  *
1131  * This function returns zero if the volume identifier header is all right, and
1132  * %1 if not.
1133  */
1134 static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
1135                                   const struct ubi_vid_hdr *vid_hdr)
1136 {
1137         int err;
1138         uint32_t magic;
1139
1140         magic = ubi32_to_cpu(vid_hdr->magic);
1141         if (magic != UBI_VID_HDR_MAGIC) {
1142                 ubi_err("bad VID header magic %#08x at PEB %d, must be %#08x",
1143                         magic, pnum, UBI_VID_HDR_MAGIC);
1144                 goto fail;
1145         }
1146
1147         err = validate_vid_hdr(ubi, vid_hdr);
1148         if (err) {
1149                 ubi_err("paranoid check failed for PEB %d", pnum);
1150                 goto fail;
1151         }
1152
1153         return err;
1154
1155 fail:
1156         ubi_err("paranoid check failed for PEB %d", pnum);
1157         ubi_dbg_dump_vid_hdr(vid_hdr);
1158         ubi_dbg_dump_stack();
1159         return 1;
1160
1161 }
1162
1163 /**
1164  * paranoid_check_peb_vid_hdr - check that the volume identifier header of a
1165  * physical eraseblock is in-place and is all right.
1166  * @ubi: UBI device description object
1167  * @pnum: the physical eraseblock number to check
1168  *
1169  * This function returns zero if the volume identifier header is all right,
1170  * %1 if not, and a negative error code if an error occurred.
1171  */
1172 static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
1173 {
1174         int err;
1175         uint32_t crc, hdr_crc;
1176         struct ubi_vid_hdr *vid_hdr;
1177         void *p;
1178
1179         vid_hdr = ubi_zalloc_vid_hdr(ubi);
1180         if (!vid_hdr)
1181                 return -ENOMEM;
1182
1183         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1184         err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1185                           ubi->vid_hdr_alsize);
1186         if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
1187                 goto exit;
1188
1189         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_EC_HDR_SIZE_CRC);
1190         hdr_crc = ubi32_to_cpu(vid_hdr->hdr_crc);
1191         if (hdr_crc != crc) {
1192                 ubi_err("bad VID header CRC at PEB %d, calculated %#08x, "
1193                         "read %#08x", pnum, crc, hdr_crc);
1194                 ubi_err("paranoid check failed for PEB %d", pnum);
1195                 ubi_dbg_dump_vid_hdr(vid_hdr);
1196                 ubi_dbg_dump_stack();
1197                 err = 1;
1198                 goto exit;
1199         }
1200
1201         err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
1202
1203 exit:
1204         ubi_free_vid_hdr(ubi, vid_hdr);
1205         return err;
1206 }
1207
1208 /**
1209  * paranoid_check_all_ff - check that a region of flash is empty.
1210  * @ubi: UBI device description object
1211  * @pnum: the physical eraseblock number to check
1212  * @offset: the starting offset within the physical eraseblock to check
1213  * @len: the length of the region to check
1214  *
1215  * This function returns zero if only 0xFF bytes are present at offset
1216  * @offset of the physical eraseblock @pnum, %1 if not, and a negative error
1217  * code if an error occurred.
1218  */
1219 static int paranoid_check_all_ff(const struct ubi_device *ubi, int pnum,
1220                                  int offset, int len)
1221 {
1222         size_t read;
1223         int err;
1224         void *buf;
1225         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1226
1227         buf = kzalloc(len, GFP_KERNEL);
1228         if (!buf)
1229                 return -ENOMEM;
1230
1231         err = ubi->mtd->read(ubi->mtd, addr, len, &read, buf);
1232         if (err && err != -EUCLEAN) {
1233                 ubi_err("error %d while reading %d bytes from PEB %d:%d, "
1234                         "read %zd bytes", err, len, pnum, offset, read);
1235                 goto error;
1236         }
1237
1238         err = check_pattern(buf, 0xFF, len);
1239         if (err == 0) {
1240                 ubi_err("flash region at PEB %d:%d, length %d does not "
1241                         "contain all 0xFF bytes", pnum, offset, len);
1242                 goto fail;
1243         }
1244
1245         kfree(buf);
1246         return 0;
1247
1248 fail:
1249         ubi_err("paranoid check failed for PEB %d", pnum);
1250         dbg_msg("hex dump of the %d-%d region", offset, offset + len);
1251         ubi_dbg_hexdump(buf, len);
1252         err = 1;
1253 error:
1254         ubi_dbg_dump_stack();
1255         kfree(buf);
1256         return err;
1257 }
1258
1259 #endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */