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 sub-system.
  24  *
  25  * This sub-system provides a uniform way to work with all kinds of the
  26  * underlying MTD devices. It also implements handy functions for reading and
  27  * writing UBI 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
  31  * sub-system 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 sub-system does the following trick in order to avoid this extra
  83  * copy. It always allocates a @ubi->vid_hdr_alsize bytes buffer for the VID
  84  * header and returns a pointer to offset @ubi->vid_hdr_shift of this buffer.
  85  * When the VID header is being written out, it shifts the VID header pointer
  86  * back and 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 #else
 102 #define paranoid_check_not_bad(ubi, pnum) 0
 103 #define paranoid_check_peb_ec_hdr(ubi, pnum)  0
 104 #define paranoid_check_ec_hdr(ubi, pnum, ec_hdr)  0
 105 #define paranoid_check_peb_vid_hdr(ubi, pnum) 0
 106 #define paranoid_check_vid_hdr(ubi, pnum, vid_hdr) 0
 107 #endif
 108
 109 /**
 110  * ubi_io_read - read data from a physical eraseblock.
 111  * @ubi: UBI device description object
 112  * @buf: buffer where to store the read data
 113  * @pnum: physical eraseblock number to read from
 114  * @offset: offset within the physical eraseblock from where to read
 115  * @len: how many bytes to read
 116  *
 117  * This function reads data from offset @offset of physical eraseblock @pnum
 118  * and stores the read data in the @buf buffer. The following return codes are
 119  * possible:
 120  *
 121  * o %0 if all the requested data were successfully read;
 122  * o %UBI_IO_BITFLIPS if all the requested data were successfully read, but
 123  *   correctable bit-flips were detected; this is harmless but may indicate
 124  *   that this eraseblock may become bad soon (but do not have to);
 125  * o %-EBADMSG if the MTD subsystem reported about data integrity problems, for
 126  *   example it can be an ECC error in case of NAND; this most probably means
 127  *   that the data is corrupted;
 128  * o %-EIO if some I/O error occurred;
 129  * o other negative error codes in case of other errors.
 130  */
 131 int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 132                 int len)
 133 {
 134         int err, retries = 0;
 135         size_t read;
 136         loff_t addr;
 137
 138         dbg_io("read %d bytes from PEB %d:%d", len, pnum, offset);
 139
 140         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 141         ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 142         ubi_assert(len > 0);
 143
 144         err = paranoid_check_not_bad(ubi, pnum);
 145         if (err)
 146                 return err > 0 ? -EINVAL : err;
 147
 148         addr = (loff_t)pnum * ubi->peb_size + offset;
 149 retry:
 150         err = ubi->mtd->read(ubi->mtd, addr, len, &read, buf);
 151         if (err) {
 152                 if (err == -EUCLEAN) {
 153                         /*
 154                          * -EUCLEAN is reported if there was a bit-flip which
 155                          * was corrected, so this is harmless.
 156                          *
 157                          * We do not report about it here unless debugging is
 158                          * enabled. A corresponding message will be printed
 159                          * later, when it is has been scrubbed.
 160                          */
 161                         dbg_msg("fixable bit-flip detected at PEB %d", pnum);
 162                         ubi_assert(len == read);
 163                         return UBI_IO_BITFLIPS;
 164                 }
 165
 166                 if (read != len && retries++ < UBI_IO_RETRIES) {
 167                         dbg_io("error %d while reading %d bytes from PEB %d:%d,"
 168                                " read only %zd bytes, retry",
 169                                err, len, pnum, offset, read);
 170                         yield();
 171                         goto retry;
 172                 }
 173
 174                 ubi_err("error %d while reading %d bytes from PEB %d:%d, "
 175                         "read %zd bytes", err, len, pnum, offset, read);
 176                 ubi_dbg_dump_stack();
 177
 178                 /*
 179                  * The driver should never return -EBADMSG if it failed to read
 180                  * all the requested data. But some buggy drivers might do
 181                  * this, so we change it to -EIO.
 182                  */
 183                 if (read != len && err == -EBADMSG) {
 184                         ubi_assert(0);
 185                         err = -EIO;
 186                 }
 187         } else {
 188                 ubi_assert(len == read);
 189
 190                 if (ubi_dbg_is_bitflip()) {
 191                         dbg_gen("bit-flip (emulated)");
 192                         err = UBI_IO_BITFLIPS;
 193                 }
 194         }
 195
 196         return err;
 197 }
 198
 199 /**
 200  * ubi_io_write - write data to a physical eraseblock.
 201  * @ubi: UBI device description object
 202  * @buf: buffer with the data to write
 203  * @pnum: physical eraseblock number to write to
 204  * @offset: offset within the physical eraseblock where to write
 205  * @len: how many bytes to write
 206  *
 207  * This function writes @len bytes of data from buffer @buf to offset @offset
 208  * of physical eraseblock @pnum. If all the data were successfully written,
 209  * zero is returned. If an error occurred, this function returns a negative
 210  * error code. If %-EIO is returned, the physical eraseblock most probably went
 211  * bad.
 212  *
 213  * Note, in case of an error, it is possible that something was still written
 214  * to the flash media, but may be some garbage.
 215  */
 216 int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
 217                  int len)
 218 {
 219         int err;
 220         size_t written;
 221         loff_t addr;
 222
 223         dbg_io("write %d bytes to PEB %d:%d", len, pnum, offset);
 224
 225         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 226         ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 227         ubi_assert(offset % ubi->hdrs_min_io_size == 0);
 228         ubi_assert(len > 0 && len % ubi->hdrs_min_io_size == 0);
 229
 230         if (ubi->ro_mode) {
 231                 ubi_err("read-only mode");
 232                 return -EROFS;
 233         }
 234
 235         /* The below has to be compiled out if paranoid checks are disabled */
 236
 237         err = paranoid_check_not_bad(ubi, pnum);
 238         if (err)
 239                 return err > 0 ? -EINVAL : err;
 240
 241         /* The area we are writing to has to contain all 0xFF bytes */
 242         err = ubi_dbg_check_all_ff(ubi, pnum, offset, len);
 243         if (err)
 244                 return err > 0 ? -EINVAL : err;
 245
 246         if (offset >= ubi->leb_start) {
 247                 /*
 248                  * We write to the data area of the physical eraseblock. Make
 249                  * sure it has valid EC and VID headers.
 250                  */
 251                 err = paranoid_check_peb_ec_hdr(ubi, pnum);
 252                 if (err)
 253                         return err > 0 ? -EINVAL : err;
 254                 err = paranoid_check_peb_vid_hdr(ubi, pnum);
 255                 if (err)
 256                         return err > 0 ? -EINVAL : err;
 257         }
 258
 259         if (ubi_dbg_is_write_failure()) {
 260                 dbg_err("cannot write %d bytes to PEB %d:%d "
 261                         "(emulated)", len, pnum, offset);
 262                 ubi_dbg_dump_stack();
 263                 return -EIO;
 264         }
 265
 266         addr = (loff_t)pnum * ubi->peb_size + offset;
 267         err = ubi->mtd->write(ubi->mtd, addr, len, &written, buf);
 268         if (err) {
 269                 ubi_err("error %d while writing %d bytes to PEB %d:%d, written "
 270                         "%zd bytes", err, len, pnum, offset, written);
 271                 ubi_dbg_dump_stack();
 272                 ubi_dbg_dump_flash(ubi, pnum, offset, len);
 273         } else
 274                 ubi_assert(written == len);
 275
 276         return err;
 277 }
 278
 279 /**
 280  * erase_callback - MTD erasure call-back.
 281  * @ei: MTD erase information object.
 282  *
 283  * Note, even though MTD erase interface is asynchronous, all the current
 284  * implementations are synchronous anyway.
 285  */
 286 static void erase_callback(struct erase_info *ei)
 287 {
 288         wake_up_interruptible((wait_queue_head_t *)ei->priv);
 289 }
 290
 291 /**
 292  * do_sync_erase - synchronously erase a physical eraseblock.
 293  * @ubi: UBI device description object
 294  * @pnum: the physical eraseblock number to erase
 295  *
 296  * This function synchronously erases physical eraseblock @pnum and returns
 297  * zero in case of success and a negative error code in case of failure. If
 298  * %-EIO is returned, the physical eraseblock most probably went bad.
 299  */
 300 static int do_sync_erase(struct ubi_device *ubi, int pnum)
 301 {
 302         int err, retries = 0;
 303         struct erase_info ei;
 304         wait_queue_head_t wq;
 305
 306         dbg_io("erase PEB %d", pnum);
 307
 308 retry:
 309         init_waitqueue_head(&wq);
 310         memset(&ei, 0, sizeof(struct erase_info));
 311
 312         ei.mtd      = ubi->mtd;
 313         ei.addr     = (loff_t)pnum * ubi->peb_size;
 314         ei.len      = ubi->peb_size;
 315         ei.callback = erase_callback;
 316         ei.priv     = (unsigned long)&wq;
 317
 318         err = ubi->mtd->erase(ubi->mtd, &ei);
 319         if (err) {
 320                 if (retries++ < UBI_IO_RETRIES) {
 321                         dbg_io("error %d while erasing PEB %d, retry",
 322                                err, pnum);
 323                         yield();
 324                         goto retry;
 325                 }
 326                 ubi_err("cannot erase PEB %d, error %d", pnum, err);
 327                 ubi_dbg_dump_stack();
 328                 return err;
 329         }
 330
 331         err = wait_event_interruptible(wq, ei.state == MTD_ERASE_DONE ||
 332                                            ei.state == MTD_ERASE_FAILED);
 333         if (err) {
 334                 ubi_err("interrupted PEB %d erasure", pnum);
 335                 return -EINTR;
 336         }
 337
 338         if (ei.state == MTD_ERASE_FAILED) {
 339                 if (retries++ < UBI_IO_RETRIES) {
 340                         dbg_io("error while erasing PEB %d, retry", pnum);
 341                         yield();
 342                         goto retry;
 343                 }
 344                 ubi_err("cannot erase PEB %d", pnum);
 345                 ubi_dbg_dump_stack();
 346                 return -EIO;
 347         }
 348
 349         err = ubi_dbg_check_all_ff(ubi, pnum, 0, ubi->peb_size);
 350         if (err)
 351                 return err > 0 ? -EINVAL : err;
 352
 353         if (ubi_dbg_is_erase_failure() && !err) {
 354                 dbg_err("cannot erase PEB %d (emulated)", pnum);
 355                 return -EIO;
 356         }
 357
 358         return 0;
 359 }
 360
 361 /**
 362  * check_pattern - check if buffer contains only a certain byte pattern.
 363  * @buf: buffer to check
 364  * @patt: the pattern to check
 365  * @size: buffer size in bytes
 366  *
 367  * This function returns %1 in there are only @patt bytes in @buf, and %0 if
 368  * something else was also found.
 369  */
 370 static int check_pattern(const void *buf, uint8_t patt, int size)
 371 {
 372         int i;
 373
 374         for (i = 0; i < size; i++)
 375                 if (((const uint8_t *)buf)[i] != patt)
 376                         return 0;
 377         return 1;
 378 }
 379
 380 /* Patterns to write to a physical eraseblock when torturing it */
 381 static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
 382
 383 /**
 384  * torture_peb - test a supposedly bad physical eraseblock.
 385  * @ubi: UBI device description object
 386  * @pnum: the physical eraseblock number to test
 387  *
 388  * This function returns %-EIO if the physical eraseblock did not pass the
 389  * test, a positive number of erase operations done if the test was
 390  * successfully passed, and other negative error codes in case of other errors.
 391  */
 392 static int torture_peb(struct ubi_device *ubi, int pnum)
 393 {
 394         int err, i, patt_count;
 395
 396         ubi_msg("run torture test for PEB %d", pnum);
 397         patt_count = ARRAY_SIZE(patterns);
 398         ubi_assert(patt_count > 0);
 399
 400         mutex_lock(&ubi->buf_mutex);
 401         for (i = 0; i < patt_count; i++) {
 402                 err = do_sync_erase(ubi, pnum);
 403                 if (err)
 404                         goto out;
 405
 406                 /* Make sure the PEB contains only 0xFF bytes */
 407                 err = ubi_io_read(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 408                 if (err)
 409                         goto out;
 410
 411                 err = check_pattern(ubi->peb_buf1, 0xFF, ubi->peb_size);
 412                 if (err == 0) {
 413                         ubi_err("erased PEB %d, but a non-0xFF byte found",
 414                                 pnum);
 415                         err = -EIO;
 416                         goto out;
 417                 }
 418
 419                 /* Write a pattern and check it */
 420                 memset(ubi->peb_buf1, patterns[i], ubi->peb_size);
 421                 err = ubi_io_write(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 422                 if (err)
 423                         goto out;
 424
 425                 memset(ubi->peb_buf1, ~patterns[i], ubi->peb_size);
 426                 err = ubi_io_read(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 427                 if (err)
 428                         goto out;
 429
 430                 err = check_pattern(ubi->peb_buf1, patterns[i], ubi->peb_size);
 431                 if (err == 0) {
 432                         ubi_err("pattern %x checking failed for PEB %d",
 433                                 patterns[i], pnum);
 434                         err = -EIO;
 435                         goto out;
 436                 }
 437         }
 438
 439         err = patt_count;
 440         ubi_msg("PEB %d passed torture test, do not mark it a bad", pnum);
 441
 442 out:
 443         mutex_unlock(&ubi->buf_mutex);
 444         if (err == UBI_IO_BITFLIPS || err == -EBADMSG) {
 445                 /*
 446                  * If a bit-flip or data integrity error was detected, the test
 447                  * has not passed because it happened on a freshly erased
 448                  * physical eraseblock which means something is wrong with it.
 449                  */
 450                 ubi_err("read problems on freshly erased PEB %d, must be bad",
 451                         pnum);
 452                 err = -EIO;
 453         }
 454         return err;
 455 }
 456
 457 /**
 458  * nor_erase_prepare - prepare a NOR flash PEB for erasure.
 459  * @ubi: UBI device description object
 460  * @pnum: physical eraseblock number to prepare
 461  *
 462  * NOR flash, or at least some of them, have peculiar embedded PEB erasure
 463  * algorithm: the PEB is first filled with zeroes, then it is erased. And
 464  * filling with zeroes starts from the end of the PEB. This was observed with
 465  * Spansion S29GL512N NOR flash.
 466  *
 467  * This means that in case of a power cut we may end up with intact data at the
 468  * beginning of the PEB, and all zeroes at the end of PEB. In other words, the
 469  * EC and VID headers are OK, but a large chunk of data at the end of PEB is
 470  * zeroed. This makes UBI mistakenly treat this PEB as used and associate it
 471  * with an LEB, which leads to subsequent failures (e.g., UBIFS fails).
 472  *
 473  * This function is called before erasing NOR PEBs and it zeroes out EC and VID
 474  * magic numbers in order to invalidate them and prevent the failures. Returns
 475  * zero in case of success and a negative error code in case of failure.
 476  */
 477 static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 478 {
 479         int err, err1;
 480         size_t written;
 481         loff_t addr;
 482         uint32_t data = 0;
 483         struct ubi_vid_hdr vid_hdr;
 484
 485         addr = (loff_t)pnum * ubi->peb_size + ubi->vid_hdr_aloffset;
 486         err = ubi->mtd->write(ubi->mtd, addr, 4, &written, (void *)&data);
 487         if (!err) {
 488                 addr -= ubi->vid_hdr_aloffset;
 489                 err = ubi->mtd->write(ubi->mtd, addr, 4, &written,
 490                                       (void *)&data);
 491                 if (!err)
 492                         return 0;
 493         }
 494
 495         /*
 496          * We failed to write to the media. This was observed with Spansion
 497          * S29GL512N NOR flash. Most probably the eraseblock erasure was
 498          * interrupted at a very inappropriate moment, so it became unwritable.
 499          * In this case we probably anyway have garbage in this PEB.
 500          */
 501         err1 = ubi_io_read_vid_hdr(ubi, pnum, &vid_hdr, 0);
 502         if (err1 == UBI_IO_BAD_VID_HDR)
 503                 /*
 504                  * The VID header is corrupted, so we can safely erase this
 505                  * PEB and not afraid that it will be treated as a valid PEB in
 506                  * case of an unclean reboot.
 507                  */
 508                 return 0;
 509
 510         /*
 511          * The PEB contains a valid VID header, but we cannot invalidate it.
 512          * Supposedly the flash media or the driver is screwed up, so return an
 513          * error.
 514          */
 515         ubi_err("cannot invalidate PEB %d, write returned %d read returned %d",
 516                 pnum, err, err1);
 517         ubi_dbg_dump_flash(ubi, pnum, 0, ubi->peb_size);
 518         return -EIO;
 519 }
 520
 521 /**
 522  * ubi_io_sync_erase - synchronously erase a physical eraseblock.
 523  * @ubi: UBI device description object
 524  * @pnum: physical eraseblock number to erase
 525  * @torture: if this physical eraseblock has to be tortured
 526  *
 527  * This function synchronously erases physical eraseblock @pnum. If @torture
 528  * flag is not zero, the physical eraseblock is checked by means of writing
 529  * different patterns to it and reading them back. If the torturing is enabled,
 530  * the physical eraseblock is erased more than once.
 531  *
 532  * This function returns the number of erasures made in case of success, %-EIO
 533  * if the erasure failed or the torturing test failed, and other negative error
 534  * codes in case of other errors. Note, %-EIO means that the physical
 535  * eraseblock is bad.
 536  */
 537 int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
 538 {
 539         int err, ret = 0;
 540
 541         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 542
 543         err = paranoid_check_not_bad(ubi, pnum);
 544         if (err != 0)
 545                 return err > 0 ? -EINVAL : err;
 546
 547         if (ubi->ro_mode) {
 548                 ubi_err("read-only mode");
 549                 return -EROFS;
 550         }
 551
 552         if (ubi->nor_flash) {
 553                 err = nor_erase_prepare(ubi, pnum);
 554                 if (err)
 555                         return err;
 556         }
 557
 558         if (torture) {
 559                 ret = torture_peb(ubi, pnum);
 560                 if (ret < 0)
 561                         return ret;
 562         }
 563
 564         err = do_sync_erase(ubi, pnum);
 565         if (err)
 566                 return err;
 567
 568         return ret + 1;
 569 }
 570
 571 /**
 572  * ubi_io_is_bad - check if a physical eraseblock is bad.
 573  * @ubi: UBI device description object
 574  * @pnum: the physical eraseblock number to check
 575  *
 576  * This function returns a positive number if the physical eraseblock is bad,
 577  * zero if not, and a negative error code if an error occurred.
 578  */
 579 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum)
 580 {
 581         struct mtd_info *mtd = ubi->mtd;
 582
 583         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 584
 585         if (ubi->bad_allowed) {
 586                 int ret;
 587
 588                 ret = mtd->block_isbad(mtd, (loff_t)pnum * ubi->peb_size);
 589                 if (ret < 0)
 590                         ubi_err("error %d while checking if PEB %d is bad",
 591                                 ret, pnum);
 592                 else if (ret)
 593                         dbg_io("PEB %d is bad", pnum);
 594                 return ret;
 595         }
 596
 597         return 0;
 598 }
 599
 600 /**
 601  * ubi_io_mark_bad - mark a physical eraseblock as bad.
 602  * @ubi: UBI device description object
 603  * @pnum: the physical eraseblock number to mark
 604  *
 605  * This function returns zero in case of success and a negative error code in
 606  * case of failure.
 607  */
 608 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
 609 {
 610         int err;
 611         struct mtd_info *mtd = ubi->mtd;
 612
 613         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 614
 615         if (ubi->ro_mode) {
 616                 ubi_err("read-only mode");
 617                 return -EROFS;
 618         }
 619
 620         if (!ubi->bad_allowed)
 621                 return 0;
 622
 623         err = mtd->block_markbad(mtd, (loff_t)pnum * ubi->peb_size);
 624         if (err)
 625                 ubi_err("cannot mark PEB %d bad, error %d", pnum, err);
 626         return err;
 627 }
 628
 629 /**
 630  * validate_ec_hdr - validate an erase counter header.
 631  * @ubi: UBI device description object
 632  * @ec_hdr: the erase counter header to check
 633  *
 634  * This function returns zero if the erase counter header is OK, and %1 if
 635  * not.
 636  */
 637 static int validate_ec_hdr(const struct ubi_device *ubi,
 638                            const struct ubi_ec_hdr *ec_hdr)
 639 {
 640         long long ec;
 641         int vid_hdr_offset, leb_start;
 642
 643         ec = be64_to_cpu(ec_hdr->ec);
 644         vid_hdr_offset = be32_to_cpu(ec_hdr->vid_hdr_offset);
 645         leb_start = be32_to_cpu(ec_hdr->data_offset);
 646
 647         if (ec_hdr->version != UBI_VERSION) {
 648                 ubi_err("node with incompatible UBI version found: "
 649                         "this UBI version is %d, image version is %d",
 650                         UBI_VERSION, (int)ec_hdr->version);
 651                 goto bad;
 652         }
 653
 654         if (vid_hdr_offset != ubi->vid_hdr_offset) {
 655                 ubi_err("bad VID header offset %d, expected %d",
 656                         vid_hdr_offset, ubi->vid_hdr_offset);
 657                 goto bad;
 658         }
 659
 660         if (leb_start != ubi->leb_start) {
 661                 ubi_err("bad data offset %d, expected %d",
 662                         leb_start, ubi->leb_start);
 663                 goto bad;
 664         }
 665
 666         if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
 667                 ubi_err("bad erase counter %lld", ec);
 668                 goto bad;
 669         }
 670
 671         return 0;
 672
 673 bad:
 674         ubi_err("bad EC header");
 675         ubi_dbg_dump_ec_hdr(ec_hdr);
 676         ubi_dbg_dump_stack();
 677         return 1;
 678 }
 679
 680 /**
 681  * ubi_io_read_ec_hdr - read and check an erase counter header.
 682  * @ubi: UBI device description object
 683  * @pnum: physical eraseblock to read from
 684  * @ec_hdr: a &struct ubi_ec_hdr object where to store the read erase counter
 685  * header
 686  * @verbose: be verbose if the header is corrupted or was not found
 687  *
 688  * This function reads erase counter header from physical eraseblock @pnum and
 689  * stores it in @ec_hdr. This function also checks CRC checksum of the read
 690  * erase counter header. The following codes may be returned:
 691  *
 692  * o %0 if the CRC checksum is correct and the header was successfully read;
 693  * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 694  *   and corrected by the flash driver; this is harmless but may indicate that
 695  *   this eraseblock may become bad soon (but may be not);
 696  * o %UBI_IO_BAD_EC_HDR if the erase counter header is corrupted (a CRC error);
 697  * o %UBI_IO_PEB_EMPTY if the physical eraseblock is empty;
 698  * o a negative error code in case of failure.
 699  */
 700 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 701                        struct ubi_ec_hdr *ec_hdr, int verbose)
 702 {
 703         int err, read_err = 0;
 704         uint32_t crc, magic, hdr_crc;
 705
 706         dbg_io("read EC header from PEB %d", pnum);
 707         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 708
 709         err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
 710         if (err) {
 711                 if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
 712                         return err;
 713
 714                 /*
 715                  * We read all the data, but either a correctable bit-flip
 716                  * occurred, or MTD reported about some data integrity error,
 717                  * like an ECC error in case of NAND. The former is harmless,
 718                  * the later may mean that the read data is corrupted. But we
 719                  * have a CRC check-sum and we will detect this. If the EC
 720                  * header is still OK, we just report this as there was a
 721                  * bit-flip.
 722                  */
 723                 read_err = err;
 724         }
 725
 726         magic = be32_to_cpu(ec_hdr->magic);
 727         if (magic != UBI_EC_HDR_MAGIC) {
 728                 /*
 729                  * The magic field is wrong. Let's check if we have read all
 730                  * 0xFF. If yes, this physical eraseblock is assumed to be
 731                  * empty.
 732                  *
 733                  * But if there was a read error, we do not test it for all
 734                  * 0xFFs. Even if it does contain all 0xFFs, this error
 735                  * indicates that something is still wrong with this physical
 736                  * eraseblock and we anyway cannot treat it as empty.
 737                  */
 738                 if (read_err != -EBADMSG &&
 739                     check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
 740                         /* The physical eraseblock is supposedly empty */
 741                         if (verbose)
 742                                 ubi_warn("no EC header found at PEB %d, "
 743                                          "only 0xFF bytes", pnum);
 744                         else if (UBI_IO_DEBUG)
 745                                 dbg_msg("no EC header found at PEB %d, "
 746                                         "only 0xFF bytes", pnum);
 747                         return UBI_IO_PEB_EMPTY;
 748                 }
 749
 750                 /*
 751                  * This is not a valid erase counter header, and these are not
 752                  * 0xFF bytes. Report that the header is corrupted.
 753                  */
 754                 if (verbose) {
 755                         ubi_warn("bad magic number at PEB %d: %08x instead of "
 756                                  "%08x", pnum, magic, UBI_EC_HDR_MAGIC);
 757                         ubi_dbg_dump_ec_hdr(ec_hdr);
 758                 } else if (UBI_IO_DEBUG)
 759                         dbg_msg("bad magic number at PEB %d: %08x instead of "
 760                                 "%08x", pnum, magic, UBI_EC_HDR_MAGIC);
 761                 return UBI_IO_BAD_EC_HDR;
 762         }
 763
 764         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 765         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
 766
 767         if (hdr_crc != crc) {
 768                 if (verbose) {
 769                         ubi_warn("bad EC header CRC at PEB %d, calculated "
 770                                  "%#08x, read %#08x", pnum, crc, hdr_crc);
 771                         ubi_dbg_dump_ec_hdr(ec_hdr);
 772                 } else if (UBI_IO_DEBUG)
 773                         dbg_msg("bad EC header CRC at PEB %d, calculated "
 774                                 "%#08x, read %#08x", pnum, crc, hdr_crc);
 775                 return UBI_IO_BAD_EC_HDR;
 776         }
 777
 778         /* And of course validate what has just been read from the media */
 779         err = validate_ec_hdr(ubi, ec_hdr);
 780         if (err) {
 781                 ubi_err("validation failed for PEB %d", pnum);
 782                 return -EINVAL;
 783         }
 784
 785         return read_err ? UBI_IO_BITFLIPS : 0;
 786 }
 787
 788 /**
 789  * ubi_io_write_ec_hdr - write an erase counter header.
 790  * @ubi: UBI device description object
 791  * @pnum: physical eraseblock to write to
 792  * @ec_hdr: the erase counter header to write
 793  *
 794  * This function writes erase counter header described by @ec_hdr to physical
 795  * eraseblock @pnum. It also fills most fields of @ec_hdr before writing, so
 796  * the caller do not have to fill them. Callers must only fill the @ec_hdr->ec
 797  * field.
 798  *
 799  * This function returns zero in case of success and a negative error code in
 800  * case of failure. If %-EIO is returned, the physical eraseblock most probably
 801  * went bad.
 802  */
 803 int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 804                         struct ubi_ec_hdr *ec_hdr)
 805 {
 806         int err;
 807         uint32_t crc;
 808
 809         dbg_io("write EC header to PEB %d", pnum);
 810         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 811
 812         ec_hdr->magic = cpu_to_be32(UBI_EC_HDR_MAGIC);
 813         ec_hdr->version = UBI_VERSION;
 814         ec_hdr->vid_hdr_offset = cpu_to_be32(ubi->vid_hdr_offset);
 815         ec_hdr->data_offset = cpu_to_be32(ubi->leb_start);
 816         ec_hdr->image_seq = cpu_to_be32(ubi->image_seq);
 817         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 818         ec_hdr->hdr_crc = cpu_to_be32(crc);
 819
 820         err = paranoid_check_ec_hdr(ubi, pnum, ec_hdr);
 821         if (err)
 822                 return -EINVAL;
 823
 824         err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
 825         return err;
 826 }
 827
 828 /**
 829  * validate_vid_hdr - validate a volume identifier header.
 830  * @ubi: UBI device description object
 831  * @vid_hdr: the volume identifier header to check
 832  *
 833  * This function checks that data stored in the volume identifier header
 834  * @vid_hdr. Returns zero if the VID header is OK and %1 if not.
 835  */
 836 static int validate_vid_hdr(const struct ubi_device *ubi,
 837                             const struct ubi_vid_hdr *vid_hdr)
 838 {
 839         int vol_type = vid_hdr->vol_type;
 840         int copy_flag = vid_hdr->copy_flag;
 841         int vol_id = be32_to_cpu(vid_hdr->vol_id);
 842         int lnum = be32_to_cpu(vid_hdr->lnum);
 843         int compat = vid_hdr->compat;
 844         int data_size = be32_to_cpu(vid_hdr->data_size);
 845         int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
 846         int data_pad = be32_to_cpu(vid_hdr->data_pad);
 847         int data_crc = be32_to_cpu(vid_hdr->data_crc);
 848         int usable_leb_size = ubi->leb_size - data_pad;
 849
 850         if (copy_flag != 0 && copy_flag != 1) {
 851                 dbg_err("bad copy_flag");
 852                 goto bad;
 853         }
 854
 855         if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
 856             data_pad < 0) {
 857                 dbg_err("negative values");
 858                 goto bad;
 859         }
 860
 861         if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
 862                 dbg_err("bad vol_id");
 863                 goto bad;
 864         }
 865
 866         if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
 867                 dbg_err("bad compat");
 868                 goto bad;
 869         }
 870
 871         if (vol_id >= UBI_INTERNAL_VOL_START && compat != UBI_COMPAT_DELETE &&
 872             compat != UBI_COMPAT_RO && compat != UBI_COMPAT_PRESERVE &&
 873             compat != UBI_COMPAT_REJECT) {
 874                 dbg_err("bad compat");
 875                 goto bad;
 876         }
 877
 878         if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
 879                 dbg_err("bad vol_type");
 880                 goto bad;
 881         }
 882
 883         if (data_pad >= ubi->leb_size / 2) {
 884                 dbg_err("bad data_pad");
 885                 goto bad;
 886         }
 887
 888         if (vol_type == UBI_VID_STATIC) {
 889                 /*
 890                  * Although from high-level point of view static volumes may
 891                  * contain zero bytes of data, but no VID headers can contain
 892                  * zero at these fields, because they empty volumes do not have
 893                  * mapped logical eraseblocks.
 894                  */
 895                 if (used_ebs == 0) {
 896                         dbg_err("zero used_ebs");
 897                         goto bad;
 898                 }
 899                 if (data_size == 0) {
 900                         dbg_err("zero data_size");
 901                         goto bad;
 902                 }
 903                 if (lnum < used_ebs - 1) {
 904                         if (data_size != usable_leb_size) {
 905                                 dbg_err("bad data_size");
 906                                 goto bad;
 907                         }
 908                 } else if (lnum == used_ebs - 1) {
 909                         if (data_size == 0) {
 910                                 dbg_err("bad data_size at last LEB");
 911                                 goto bad;
 912                         }
 913                 } else {
 914                         dbg_err("too high lnum");
 915                         goto bad;
 916                 }
 917         } else {
 918                 if (copy_flag == 0) {
 919                         if (data_crc != 0) {
 920                                 dbg_err("non-zero data CRC");
 921                                 goto bad;
 922                         }
 923                         if (data_size != 0) {
 924                                 dbg_err("non-zero data_size");
 925                                 goto bad;
 926                         }
 927                 } else {
 928                         if (data_size == 0) {
 929                                 dbg_err("zero data_size of copy");
 930                                 goto bad;
 931                         }
 932                 }
 933                 if (used_ebs != 0) {
 934                         dbg_err("bad used_ebs");
 935                         goto bad;
 936                 }
 937         }
 938
 939         return 0;
 940
 941 bad:
 942         ubi_err("bad VID header");
 943         ubi_dbg_dump_vid_hdr(vid_hdr);
 944         ubi_dbg_dump_stack();
 945         return 1;
 946 }
 947
 948 /**
 949  * ubi_io_read_vid_hdr - read and check a volume identifier header.
 950  * @ubi: UBI device description object
 951  * @pnum: physical eraseblock number to read from
 952  * @vid_hdr: &struct ubi_vid_hdr object where to store the read volume
 953  * identifier header
 954  * @verbose: be verbose if the header is corrupted or wasn't found
 955  *
 956  * This function reads the volume identifier header from physical eraseblock
 957  * @pnum and stores it in @vid_hdr. It also checks CRC checksum of the read
 958  * volume identifier header. The following codes may be returned:
 959  *
 960  * o %0 if the CRC checksum is correct and the header was successfully read;
 961  * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 962  *   and corrected by the flash driver; this is harmless but may indicate that
 963  *   this eraseblock may become bad soon;
 964  * o %UBI_IO_BAD_VID_HDR if the volume identifier header is corrupted (a CRC
 965  *   error detected);
 966  * o %UBI_IO_PEB_FREE if the physical eraseblock is free (i.e., there is no VID
 967  *   header there);
 968  * o a negative error code in case of failure.
 969  */
 970 int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 971                         struct ubi_vid_hdr *vid_hdr, int verbose)
 972 {
 973         int err, read_err = 0;
 974         uint32_t crc, magic, hdr_crc;
 975         void *p;
 976
 977         dbg_io("read VID header from PEB %d", pnum);
 978         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 979
 980         p = (char *)vid_hdr - ubi->vid_hdr_shift;
 981         err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
 982                           ubi->vid_hdr_alsize);
 983         if (err) {
 984                 if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
 985                         return err;
 986
 987                 /*
 988                  * We read all the data, but either a correctable bit-flip
 989                  * occurred, or MTD reported about some data integrity error,
 990                  * like an ECC error in case of NAND. The former is harmless,
 991                  * the later may mean the read data is corrupted. But we have a
 992                  * CRC check-sum and we will identify this. If the VID header is
 993                  * still OK, we just report this as there was a bit-flip.
 994                  */
 995                 read_err = err;
 996         }
 997
 998         magic = be32_to_cpu(vid_hdr->magic);
 999         if (magic != UBI_VID_HDR_MAGIC) {
1000                 /*
1001                  * If we have read all 0xFF bytes, the VID header probably does
1002                  * not exist and the physical eraseblock is assumed to be free.
1003                  *
1004                  * But if there was a read error, we do not test the data for
1005                  * 0xFFs. Even if it does contain all 0xFFs, this error
1006                  * indicates that something is still wrong with this physical
1007                  * eraseblock and it cannot be regarded as free.
1008                  */
1009                 if (read_err != -EBADMSG &&
1010                     check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
1011                         /* The physical eraseblock is supposedly free */
1012                         if (verbose)
1013                                 ubi_warn("no VID header found at PEB %d, "
1014                                          "only 0xFF bytes", pnum);
1015                         else if (UBI_IO_DEBUG)
1016                                 dbg_msg("no VID header found at PEB %d, "
1017                                         "only 0xFF bytes", pnum);
1018                         return UBI_IO_PEB_FREE;
1019                 }
1020
1021                 /*
1022                  * This is not a valid VID header, and these are not 0xFF
1023                  * bytes. Report that the header is corrupted.
1024                  */
1025                 if (verbose) {
1026                         ubi_warn("bad magic number at PEB %d: %08x instead of "
1027                                  "%08x", pnum, magic, UBI_VID_HDR_MAGIC);
1028                         ubi_dbg_dump_vid_hdr(vid_hdr);
1029                 } else if (UBI_IO_DEBUG)
1030                         dbg_msg("bad magic number at PEB %d: %08x instead of "
1031                                 "%08x", pnum, magic, UBI_VID_HDR_MAGIC);
1032                 return UBI_IO_BAD_VID_HDR;
1033         }
1034
1035         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1036         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1037
1038         if (hdr_crc != crc) {
1039                 if (verbose) {
1040                         ubi_warn("bad CRC at PEB %d, calculated %#08x, "
1041                                  "read %#08x", pnum, crc, hdr_crc);
1042                         ubi_dbg_dump_vid_hdr(vid_hdr);
1043                 } else if (UBI_IO_DEBUG)
1044                         dbg_msg("bad CRC at PEB %d, calculated %#08x, "
1045                                 "read %#08x", pnum, crc, hdr_crc);
1046                 return UBI_IO_BAD_VID_HDR;
1047         }
1048
1049         /* Validate the VID header that we have just read */
1050         err = validate_vid_hdr(ubi, vid_hdr);
1051         if (err) {
1052                 ubi_err("validation failed for PEB %d", pnum);
1053                 return -EINVAL;
1054         }
1055
1056         return read_err ? UBI_IO_BITFLIPS : 0;
1057 }
1058
1059 /**
1060  * ubi_io_write_vid_hdr - write a volume identifier header.
1061  * @ubi: UBI device description object
1062  * @pnum: the physical eraseblock number to write to
1063  * @vid_hdr: the volume identifier header to write
1064  *
1065  * This function writes the volume identifier header described by @vid_hdr to
1066  * physical eraseblock @pnum. This function automatically fills the
1067  * @vid_hdr->magic and the @vid_hdr->version fields, as well as calculates
1068  * header CRC checksum and stores it at vid_hdr->hdr_crc.
1069  *
1070  * This function returns zero in case of success and a negative error code in
1071  * case of failure. If %-EIO is returned, the physical eraseblock probably went
1072  * bad.
1073  */
1074 int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
1075                          struct ubi_vid_hdr *vid_hdr)
1076 {
1077         int err;
1078         uint32_t crc;
1079         void *p;
1080
1081         dbg_io("write VID header to PEB %d", pnum);
1082         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
1083
1084         err = paranoid_check_peb_ec_hdr(ubi, pnum);
1085         if (err)
1086                 return err > 0 ? -EINVAL : err;
1087
1088         vid_hdr->magic = cpu_to_be32(UBI_VID_HDR_MAGIC);
1089         vid_hdr->version = UBI_VERSION;
1090         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1091         vid_hdr->hdr_crc = cpu_to_be32(crc);
1092
1093         err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
1094         if (err)
1095                 return -EINVAL;
1096
1097         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1098         err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
1099                            ubi->vid_hdr_alsize);
1100         return err;
1101 }
1102
1103 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
1104
1105 /**
1106  * paranoid_check_not_bad - ensure that a physical eraseblock is not bad.
1107  * @ubi: UBI device description object
1108  * @pnum: physical eraseblock number to check
1109  *
1110  * This function returns zero if the physical eraseblock is good, a positive
1111  * number if it is bad and a negative error code if an error occurred.
1112  */
1113 static int paranoid_check_not_bad(const struct ubi_device *ubi, int pnum)
1114 {
1115         int err;
1116
1117         err = ubi_io_is_bad(ubi, pnum);
1118         if (!err)
1119                 return err;
1120
1121         ubi_err("paranoid check failed for PEB %d", pnum);
1122         ubi_dbg_dump_stack();
1123         return err;
1124 }
1125
1126 /**
1127  * paranoid_check_ec_hdr - check if an erase counter header is all right.
1128  * @ubi: UBI device description object
1129  * @pnum: physical eraseblock number the erase counter header belongs to
1130  * @ec_hdr: the erase counter header to check
1131  *
1132  * This function returns zero if the erase counter header contains valid
1133  * values, and %1 if not.
1134  */
1135 static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
1136                                  const struct ubi_ec_hdr *ec_hdr)
1137 {
1138         int err;
1139         uint32_t magic;
1140
1141         magic = be32_to_cpu(ec_hdr->magic);
1142         if (magic != UBI_EC_HDR_MAGIC) {
1143                 ubi_err("bad magic %#08x, must be %#08x",
1144                         magic, UBI_EC_HDR_MAGIC);
1145                 goto fail;
1146         }
1147
1148         err = validate_ec_hdr(ubi, ec_hdr);
1149         if (err) {
1150                 ubi_err("paranoid check failed for PEB %d", pnum);
1151                 goto fail;
1152         }
1153
1154         return 0;
1155
1156 fail:
1157         ubi_dbg_dump_ec_hdr(ec_hdr);
1158         ubi_dbg_dump_stack();
1159         return 1;
1160 }
1161
1162 /**
1163  * paranoid_check_peb_ec_hdr - check erase counter header.
1164  * @ubi: UBI device description object
1165  * @pnum: the physical eraseblock number to check
1166  *
1167  * This function returns zero if the erase counter header is all right, %1 if
1168  * not, and a negative error code if an error occurred.
1169  */
1170 static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
1171 {
1172         int err;
1173         uint32_t crc, hdr_crc;
1174         struct ubi_ec_hdr *ec_hdr;
1175
1176         ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
1177         if (!ec_hdr)
1178                 return -ENOMEM;
1179
1180         err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
1181         if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
1182                 goto exit;
1183
1184         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
1185         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
1186         if (hdr_crc != crc) {
1187                 ubi_err("bad CRC, calculated %#08x, read %#08x", crc, hdr_crc);
1188                 ubi_err("paranoid check failed for PEB %d", pnum);
1189                 ubi_dbg_dump_ec_hdr(ec_hdr);
1190                 ubi_dbg_dump_stack();
1191                 err = 1;
1192                 goto exit;
1193         }
1194
1195         err = paranoid_check_ec_hdr(ubi, pnum, ec_hdr);
1196
1197 exit:
1198         kfree(ec_hdr);
1199         return err;
1200 }
1201
1202 /**
1203  * paranoid_check_vid_hdr - check that a volume identifier header is all right.
1204  * @ubi: UBI device description object
1205  * @pnum: physical eraseblock number the volume identifier header belongs to
1206  * @vid_hdr: the volume identifier header to check
1207  *
1208  * This function returns zero if the volume identifier header is all right, and
1209  * %1 if not.
1210  */
1211 static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
1212                                   const struct ubi_vid_hdr *vid_hdr)
1213 {
1214         int err;
1215         uint32_t magic;
1216
1217         magic = be32_to_cpu(vid_hdr->magic);
1218         if (magic != UBI_VID_HDR_MAGIC) {
1219                 ubi_err("bad VID header magic %#08x at PEB %d, must be %#08x",
1220                         magic, pnum, UBI_VID_HDR_MAGIC);
1221                 goto fail;
1222         }
1223
1224         err = validate_vid_hdr(ubi, vid_hdr);
1225         if (err) {
1226                 ubi_err("paranoid check failed for PEB %d", pnum);
1227                 goto fail;
1228         }
1229
1230         return err;
1231
1232 fail:
1233         ubi_err("paranoid check failed for PEB %d", pnum);
1234         ubi_dbg_dump_vid_hdr(vid_hdr);
1235         ubi_dbg_dump_stack();
1236         return 1;
1237
1238 }
1239
1240 /**
1241  * paranoid_check_peb_vid_hdr - check volume identifier header.
1242  * @ubi: UBI device description object
1243  * @pnum: the physical eraseblock number to check
1244  *
1245  * This function returns zero if the volume identifier header is all right,
1246  * %1 if not, and a negative error code if an error occurred.
1247  */
1248 static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
1249 {
1250         int err;
1251         uint32_t crc, hdr_crc;
1252         struct ubi_vid_hdr *vid_hdr;
1253         void *p;
1254
1255         vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
1256         if (!vid_hdr)
1257                 return -ENOMEM;
1258
1259         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1260         err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1261                           ubi->vid_hdr_alsize);
1262         if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
1263                 goto exit;
1264
1265         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_EC_HDR_SIZE_CRC);
1266         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1267         if (hdr_crc != crc) {
1268                 ubi_err("bad VID header CRC at PEB %d, calculated %#08x, "
1269                         "read %#08x", pnum, crc, hdr_crc);
1270                 ubi_err("paranoid check failed for PEB %d", pnum);
1271                 ubi_dbg_dump_vid_hdr(vid_hdr);
1272                 ubi_dbg_dump_stack();
1273                 err = 1;
1274                 goto exit;
1275         }
1276
1277         err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
1278
1279 exit:
1280         ubi_free_vid_hdr(ubi, vid_hdr);
1281         return err;
1282 }
1283
1284 /**
1285  * ubi_dbg_check_all_ff - check that a region of flash is empty.
1286  * @ubi: UBI device description object
1287  * @pnum: the physical eraseblock number to check
1288  * @offset: the starting offset within the physical eraseblock to check
1289  * @len: the length of the region to check
1290  *
1291  * This function returns zero if only 0xFF bytes are present at offset
1292  * @offset of the physical eraseblock @pnum, %1 if not, and a negative error
1293  * code if an error occurred.
1294  */
1295 int ubi_dbg_check_all_ff(struct ubi_device *ubi, int pnum, int offset, int len)
1296 {
1297         size_t read;
1298         int err;
1299         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1300
1301         mutex_lock(&ubi->dbg_buf_mutex);
1302         err = ubi->mtd->read(ubi->mtd, addr, len, &read, ubi->dbg_peb_buf);
1303         if (err && err != -EUCLEAN) {
1304                 ubi_err("error %d while reading %d bytes from PEB %d:%d, "
1305                         "read %zd bytes", err, len, pnum, offset, read);
1306                 goto error;
1307         }
1308
1309         err = check_pattern(ubi->dbg_peb_buf, 0xFF, len);
1310         if (err == 0) {
1311                 ubi_err("flash region at PEB %d:%d, length %d does not "
1312                         "contain all 0xFF bytes", pnum, offset, len);
1313                 goto fail;
1314         }
1315         mutex_unlock(&ubi->dbg_buf_mutex);
1316
1317         return 0;
1318
1319 fail:
1320         ubi_err("paranoid check failed for PEB %d", pnum);
1321         ubi_msg("hex dump of the %d-%d region", offset, offset + len);
1322         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1323                        ubi->dbg_peb_buf, len, 1);
1324         err = 1;
1325 error:
1326         ubi_dbg_dump_stack();
1327         mutex_unlock(&ubi->dbg_buf_mutex);
1328         return err;
1329 }
1330
1331 #endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */