drivers/mtd/ubi/io.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (c) International Business Machines Corp., 2006
   4  * Copyright (c) Nokia Corporation, 2006, 2007
   5  *
   6  * Author: Artem Bityutskiy (Битюцкий Артём)
   7  */
   8
   9 /*
  10  * UBI input/output sub-system.
  11  *
  12  * This sub-system provides a uniform way to work with all kinds of the
  13  * underlying MTD devices. It also implements handy functions for reading and
  14  * writing UBI headers.
  15  *
  16  * We are trying to have a paranoid mindset and not to trust to what we read
  17  * from the flash media in order to be more secure and robust. So this
  18  * sub-system validates every single header it reads from the flash media.
  19  *
  20  * Some words about how the eraseblock headers are stored.
  21  *
  22  * The erase counter header is always stored at offset zero. By default, the
  23  * VID header is stored after the EC header at the closest aligned offset
  24  * (i.e. aligned to the minimum I/O unit size). Data starts next to the VID
  25  * header at the closest aligned offset. But this default layout may be
  26  * changed. For example, for different reasons (e.g., optimization) UBI may be
  27  * asked to put the VID header at further offset, and even at an unaligned
  28  * offset. Of course, if the offset of the VID header is unaligned, UBI adds
  29  * proper padding in front of it. Data offset may also be changed but it has to
  30  * be aligned.
  31  *
  32  * About minimal I/O units. In general, UBI assumes flash device model where
  33  * there is only one minimal I/O unit size. E.g., in case of NOR flash it is 1,
  34  * in case of NAND flash it is a NAND page, etc. This is reported by MTD in the
  35  * @ubi->mtd->writesize field. But as an exception, UBI admits use of another
  36  * (smaller) minimal I/O unit size for EC and VID headers to make it possible
  37  * to do different optimizations.
  38  *
  39  * This is extremely useful in case of NAND flashes which admit of several
  40  * write operations to one NAND page. In this case UBI can fit EC and VID
  41  * headers at one NAND page. Thus, UBI may use "sub-page" size as the minimal
  42  * I/O unit for the headers (the @ubi->hdrs_min_io_size field). But it still
  43  * reports NAND page size (@ubi->min_io_size) as a minimal I/O unit for the UBI
  44  * users.
  45  *
  46  * Example: some Samsung NANDs with 2KiB pages allow 4x 512-byte writes, so
  47  * although the minimal I/O unit is 2K, UBI uses 512 bytes for EC and VID
  48  * headers.
  49  *
  50  * Q: why not just to treat sub-page as a minimal I/O unit of this flash
  51  * device, e.g., make @ubi->min_io_size = 512 in the example above?
  52  *
  53  * A: because when writing a sub-page, MTD still writes a full 2K page but the
  54  * bytes which are not relevant to the sub-page are 0xFF. So, basically,
  55  * writing 4x512 sub-pages is 4 times slower than writing one 2KiB NAND page.
  56  * Thus, we prefer to use sub-pages only for EC and VID headers.
  57  *
  58  * As it was noted above, the VID header may start at a non-aligned offset.
  59  * For example, in case of a 2KiB page NAND flash with a 512 bytes sub-page,
  60  * the VID header may reside at offset 1984 which is the last 64 bytes of the
  61  * last sub-page (EC header is always at offset zero). This causes some
  62  * difficulties when reading and writing VID headers.
  63  *
  64  * Suppose we have a 64-byte buffer and we read a VID header at it. We change
  65  * the data and want to write this VID header out. As we can only write in
  66  * 512-byte chunks, we have to allocate one more buffer and copy our VID header
  67  * to offset 448 of this buffer.
  68  *
  69  * The I/O sub-system does the following trick in order to avoid this extra
  70  * copy. It always allocates a @ubi->vid_hdr_alsize bytes buffer for the VID
  71  * header and returns a pointer to offset @ubi->vid_hdr_shift of this buffer.
  72  * When the VID header is being written out, it shifts the VID header pointer
  73  * back and writes the whole sub-page.
  74  */
  75
  76 #include <linux/crc32.h>
  77 #include <linux/err.h>
  78 #include <linux/slab.h>
  79 #include "ubi.h"
  80
  81 static int self_check_not_bad(const struct ubi_device *ubi, int pnum);
  82 static int self_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum);
  83 static int self_check_ec_hdr(const struct ubi_device *ubi, int pnum,
  84                              const struct ubi_ec_hdr *ec_hdr);
  85 static int self_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum);
  86 static int self_check_vid_hdr(const struct ubi_device *ubi, int pnum,
  87                               const struct ubi_vid_hdr *vid_hdr);
  88 static int self_check_write(struct ubi_device *ubi, const void *buf, int pnum,
  89                             int offset, int len);
  90
  91 /**
  92  * ubi_io_read - read data from a physical eraseblock.
  93  * @ubi: UBI device description object
  94  * @buf: buffer where to store the read data
  95  * @pnum: physical eraseblock number to read from
  96  * @offset: offset within the physical eraseblock from where to read
  97  * @len: how many bytes to read
  98  *
  99  * This function reads data from offset @offset of physical eraseblock @pnum
 100  * and stores the read data in the @buf buffer. The following return codes are
 101  * possible:
 102  *
 103  * o %0 if all the requested data were successfully read;
 104  * o %UBI_IO_BITFLIPS if all the requested data were successfully read, but
 105  *   correctable bit-flips were detected; this is harmless but may indicate
 106  *   that this eraseblock may become bad soon (but do not have to);
 107  * o %-EBADMSG if the MTD subsystem reported about data integrity problems, for
 108  *   example it can be an ECC error in case of NAND; this most probably means
 109  *   that the data is corrupted;
 110  * o %-EIO if some I/O error occurred;
 111  * o other negative error codes in case of other errors.
 112  */
 113 int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 114                 int len)
 115 {
 116         int err, retries = 0;
 117         size_t read;
 118         loff_t addr;
 119
 120         dbg_io("read %d bytes from PEB %d:%d", len, pnum, offset);
 121
 122         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 123         ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 124         ubi_assert(len > 0);
 125
 126         err = self_check_not_bad(ubi, pnum);
 127         if (err)
 128                 return err;
 129
 130         /*
 131          * Deliberately corrupt the buffer to improve robustness. Indeed, if we
 132          * do not do this, the following may happen:
 133          * 1. The buffer contains data from previous operation, e.g., read from
 134          *    another PEB previously. The data looks like expected, e.g., if we
 135          *    just do not read anything and return - the caller would not
 136          *    notice this. E.g., if we are reading a VID header, the buffer may
 137          *    contain a valid VID header from another PEB.
 138          * 2. The driver is buggy and returns us success or -EBADMSG or
 139          *    -EUCLEAN, but it does not actually put any data to the buffer.
 140          *
 141          * This may confuse UBI or upper layers - they may think the buffer
 142          * contains valid data while in fact it is just old data. This is
 143          * especially possible because UBI (and UBIFS) relies on CRC, and
 144          * treats data as correct even in case of ECC errors if the CRC is
 145          * correct.
 146          *
 147          * Try to prevent this situation by changing the first byte of the
 148          * buffer.
 149          */
 150         *((uint8_t *)buf) ^= 0xFF;
 151
 152         addr = (loff_t)pnum * ubi->peb_size + offset;
 153 retry:
 154         err = mtd_read(ubi->mtd, addr, len, &read, buf);
 155         if (err) {
 156                 const char *errstr = mtd_is_eccerr(err) ? " (ECC error)" : "";
 157
 158                 if (mtd_is_bitflip(err)) {
 159                         /*
 160                          * -EUCLEAN is reported if there was a bit-flip which
 161                          * was corrected, so this is harmless.
 162                          *
 163                          * We do not report about it here unless debugging is
 164                          * enabled. A corresponding message will be printed
 165                          * later, when it is has been scrubbed.
 166                          */
 167                         ubi_msg(ubi, "fixable bit-flip detected at PEB %d",
 168                                 pnum);
 169                         ubi_assert(len == read);
 170                         return UBI_IO_BITFLIPS;
 171                 }
 172
 173                 if (retries++ < UBI_IO_RETRIES) {
 174                         ubi_warn(ubi, "error %d%s while reading %d bytes from PEB %d:%d, read only %zd bytes, retry",
 175                                  err, errstr, len, pnum, offset, read);
 176                         yield();
 177                         goto retry;
 178                 }
 179
 180                 ubi_err(ubi, "error %d%s while reading %d bytes from PEB %d:%d, read %zd bytes",
 181                         err, errstr, len, pnum, offset, read);
 182                 dump_stack();
 183
 184                 /*
 185                  * The driver should never return -EBADMSG if it failed to read
 186                  * all the requested data. But some buggy drivers might do
 187                  * this, so we change it to -EIO.
 188                  */
 189                 if (read != len && mtd_is_eccerr(err)) {
 190                         ubi_assert(0);
 191                         err = -EIO;
 192                 }
 193         } else {
 194                 ubi_assert(len == read);
 195
 196                 if (ubi_dbg_is_bitflip(ubi)) {
 197                         dbg_gen("bit-flip (emulated)");
 198                         err = UBI_IO_BITFLIPS;
 199                 }
 200         }
 201
 202         return err;
 203 }
 204
 205 /**
 206  * ubi_io_write - write data to a physical eraseblock.
 207  * @ubi: UBI device description object
 208  * @buf: buffer with the data to write
 209  * @pnum: physical eraseblock number to write to
 210  * @offset: offset within the physical eraseblock where to write
 211  * @len: how many bytes to write
 212  *
 213  * This function writes @len bytes of data from buffer @buf to offset @offset
 214  * of physical eraseblock @pnum. If all the data were successfully written,
 215  * zero is returned. If an error occurred, this function returns a negative
 216  * error code. If %-EIO is returned, the physical eraseblock most probably went
 217  * bad.
 218  *
 219  * Note, in case of an error, it is possible that something was still written
 220  * to the flash media, but may be some garbage.
 221  */
 222 int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
 223                  int len)
 224 {
 225         int err;
 226         size_t written;
 227         loff_t addr;
 228
 229         dbg_io("write %d bytes to PEB %d:%d", len, pnum, offset);
 230
 231         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 232         ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 233         ubi_assert(offset % ubi->hdrs_min_io_size == 0);
 234         ubi_assert(len > 0 && len % ubi->hdrs_min_io_size == 0);
 235
 236         if (ubi->ro_mode) {
 237                 ubi_err(ubi, "read-only mode");
 238                 return -EROFS;
 239         }
 240
 241         err = self_check_not_bad(ubi, pnum);
 242         if (err)
 243                 return err;
 244
 245         /* The area we are writing to has to contain all 0xFF bytes */
 246         err = ubi_self_check_all_ff(ubi, pnum, offset, len);
 247         if (err)
 248                 return err;
 249
 250         if (offset >= ubi->leb_start) {
 251                 /*
 252                  * We write to the data area of the physical eraseblock. Make
 253                  * sure it has valid EC and VID headers.
 254                  */
 255                 err = self_check_peb_ec_hdr(ubi, pnum);
 256                 if (err)
 257                         return err;
 258                 err = self_check_peb_vid_hdr(ubi, pnum);
 259                 if (err)
 260                         return err;
 261         }
 262
 263         if (ubi_dbg_is_write_failure(ubi)) {
 264                 ubi_err(ubi, "cannot write %d bytes to PEB %d:%d (emulated)",
 265                         len, pnum, offset);
 266                 dump_stack();
 267                 return -EIO;
 268         }
 269
 270         addr = (loff_t)pnum * ubi->peb_size + offset;
 271         err = mtd_write(ubi->mtd, addr, len, &written, buf);
 272         if (err) {
 273                 ubi_err(ubi, "error %d while writing %d bytes to PEB %d:%d, written %zd bytes",
 274                         err, len, pnum, offset, written);
 275                 dump_stack();
 276                 ubi_dump_flash(ubi, pnum, offset, len);
 277         } else
 278                 ubi_assert(written == len);
 279
 280         if (!err) {
 281                 err = self_check_write(ubi, buf, pnum, offset, len);
 282                 if (err)
 283                         return err;
 284
 285                 /*
 286                  * Since we always write sequentially, the rest of the PEB has
 287                  * to contain only 0xFF bytes.
 288                  */
 289                 offset += len;
 290                 len = ubi->peb_size - offset;
 291                 if (len)
 292                         err = ubi_self_check_all_ff(ubi, pnum, offset, len);
 293         }
 294
 295         return err;
 296 }
 297
 298 /**
 299  * do_sync_erase - synchronously erase a physical eraseblock.
 300  * @ubi: UBI device description object
 301  * @pnum: the physical eraseblock number to erase
 302  *
 303  * This function synchronously erases physical eraseblock @pnum and returns
 304  * zero in case of success and a negative error code in case of failure. If
 305  * %-EIO is returned, the physical eraseblock most probably went bad.
 306  */
 307 static int do_sync_erase(struct ubi_device *ubi, int pnum)
 308 {
 309         int err, retries = 0;
 310         struct erase_info ei;
 311
 312         dbg_io("erase PEB %d", pnum);
 313         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 314
 315         if (ubi->ro_mode) {
 316                 ubi_err(ubi, "read-only mode");
 317                 return -EROFS;
 318         }
 319
 320 retry:
 321         memset(&ei, 0, sizeof(struct erase_info));
 322
 323         ei.addr     = (loff_t)pnum * ubi->peb_size;
 324         ei.len      = ubi->peb_size;
 325
 326         err = mtd_erase(ubi->mtd, &ei);
 327         if (err) {
 328                 if (retries++ < UBI_IO_RETRIES) {
 329                         ubi_warn(ubi, "error %d while erasing PEB %d, retry",
 330                                  err, pnum);
 331                         yield();
 332                         goto retry;
 333                 }
 334                 ubi_err(ubi, "cannot erase PEB %d, error %d", pnum, err);
 335                 dump_stack();
 336                 return err;
 337         }
 338
 339         err = ubi_self_check_all_ff(ubi, pnum, 0, ubi->peb_size);
 340         if (err)
 341                 return err;
 342
 343         if (ubi_dbg_is_erase_failure(ubi)) {
 344                 ubi_err(ubi, "cannot erase PEB %d (emulated)", pnum);
 345                 return -EIO;
 346         }
 347
 348         return 0;
 349 }
 350
 351 /* Patterns to write to a physical eraseblock when torturing it */
 352 static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
 353
 354 /**
 355  * torture_peb - test a supposedly bad physical eraseblock.
 356  * @ubi: UBI device description object
 357  * @pnum: the physical eraseblock number to test
 358  *
 359  * This function returns %-EIO if the physical eraseblock did not pass the
 360  * test, a positive number of erase operations done if the test was
 361  * successfully passed, and other negative error codes in case of other errors.
 362  */
 363 static int torture_peb(struct ubi_device *ubi, int pnum)
 364 {
 365         int err, i, patt_count;
 366
 367         ubi_msg(ubi, "run torture test for PEB %d", pnum);
 368         patt_count = ARRAY_SIZE(patterns);
 369         ubi_assert(patt_count > 0);
 370
 371         mutex_lock(&ubi->buf_mutex);
 372         for (i = 0; i < patt_count; i++) {
 373                 err = do_sync_erase(ubi, pnum);
 374                 if (err)
 375                         goto out;
 376
 377                 /* Make sure the PEB contains only 0xFF bytes */
 378                 err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 379                 if (err)
 380                         goto out;
 381
 382                 err = ubi_check_pattern(ubi->peb_buf, 0xFF, ubi->peb_size);
 383                 if (err == 0) {
 384                         ubi_err(ubi, "erased PEB %d, but a non-0xFF byte found",
 385                                 pnum);
 386                         err = -EIO;
 387                         goto out;
 388                 }
 389
 390                 /* Write a pattern and check it */
 391                 memset(ubi->peb_buf, patterns[i], ubi->peb_size);
 392                 err = ubi_io_write(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 393                 if (err)
 394                         goto out;
 395
 396                 memset(ubi->peb_buf, ~patterns[i], ubi->peb_size);
 397                 err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 398                 if (err)
 399                         goto out;
 400
 401                 err = ubi_check_pattern(ubi->peb_buf, patterns[i],
 402                                         ubi->peb_size);
 403                 if (err == 0) {
 404                         ubi_err(ubi, "pattern %x checking failed for PEB %d",
 405                                 patterns[i], pnum);
 406                         err = -EIO;
 407                         goto out;
 408                 }
 409         }
 410
 411         err = patt_count;
 412         ubi_msg(ubi, "PEB %d passed torture test, do not mark it as bad", pnum);
 413
 414 out:
 415         mutex_unlock(&ubi->buf_mutex);
 416         if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err)) {
 417                 /*
 418                  * If a bit-flip or data integrity error was detected, the test
 419                  * has not passed because it happened on a freshly erased
 420                  * physical eraseblock which means something is wrong with it.
 421                  */
 422                 ubi_err(ubi, "read problems on freshly erased PEB %d, must be bad",
 423                         pnum);
 424                 err = -EIO;
 425         }
 426         return err;
 427 }
 428
 429 /**
 430  * nor_erase_prepare - prepare a NOR flash PEB for erasure.
 431  * @ubi: UBI device description object
 432  * @pnum: physical eraseblock number to prepare
 433  *
 434  * NOR flash, or at least some of them, have peculiar embedded PEB erasure
 435  * algorithm: the PEB is first filled with zeroes, then it is erased. And
 436  * filling with zeroes starts from the end of the PEB. This was observed with
 437  * Spansion S29GL512N NOR flash.
 438  *
 439  * This means that in case of a power cut we may end up with intact data at the
 440  * beginning of the PEB, and all zeroes at the end of PEB. In other words, the
 441  * EC and VID headers are OK, but a large chunk of data at the end of PEB is
 442  * zeroed. This makes UBI mistakenly treat this PEB as used and associate it
 443  * with an LEB, which leads to subsequent failures (e.g., UBIFS fails).
 444  *
 445  * This function is called before erasing NOR PEBs and it zeroes out EC and VID
 446  * magic numbers in order to invalidate them and prevent the failures. Returns
 447  * zero in case of success and a negative error code in case of failure.
 448  */
 449 static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 450 {
 451         int err;
 452         size_t written;
 453         loff_t addr;
 454         uint32_t data = 0;
 455         struct ubi_ec_hdr ec_hdr;
 456         struct ubi_vid_io_buf vidb;
 457
 458         /*
 459          * Note, we cannot generally define VID header buffers on stack,
 460          * because of the way we deal with these buffers (see the header
 461          * comment in this file). But we know this is a NOR-specific piece of
 462          * code, so we can do this. But yes, this is error-prone and we should
 463          * (pre-)allocate VID header buffer instead.
 464          */
 465         struct ubi_vid_hdr vid_hdr;
 466
 467         /*
 468          * If VID or EC is valid, we have to corrupt them before erasing.
 469          * It is important to first invalidate the EC header, and then the VID
 470          * header. Otherwise a power cut may lead to valid EC header and
 471          * invalid VID header, in which case UBI will treat this PEB as
 472          * corrupted and will try to preserve it, and print scary warnings.
 473          */
 474         addr = (loff_t)pnum * ubi->peb_size;
 475         err = ubi_io_read_ec_hdr(ubi, pnum, &ec_hdr, 0);
 476         if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
 477             err != UBI_IO_FF){
 478                 err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
 479                 if(err)
 480                         goto error;
 481         }
 482
 483         ubi_init_vid_buf(ubi, &vidb, &vid_hdr);
 484         ubi_assert(&vid_hdr == ubi_get_vid_hdr(&vidb));
 485
 486         err = ubi_io_read_vid_hdr(ubi, pnum, &vidb, 0);
 487         if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
 488             err != UBI_IO_FF){
 489                 addr += ubi->vid_hdr_aloffset;
 490                 err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
 491                 if (err)
 492                         goto error;
 493         }
 494         return 0;
 495
 496 error:
 497         /*
 498          * The PEB contains a valid VID or EC header, but we cannot invalidate
 499          * it. Supposedly the flash media or the driver is screwed up, so
 500          * return an error.
 501          */
 502         ubi_err(ubi, "cannot invalidate PEB %d, write returned %d", pnum, err);
 503         ubi_dump_flash(ubi, pnum, 0, ubi->peb_size);
 504         return -EIO;
 505 }
 506
 507 /**
 508  * ubi_io_sync_erase - synchronously erase a physical eraseblock.
 509  * @ubi: UBI device description object
 510  * @pnum: physical eraseblock number to erase
 511  * @torture: if this physical eraseblock has to be tortured
 512  *
 513  * This function synchronously erases physical eraseblock @pnum. If @torture
 514  * flag is not zero, the physical eraseblock is checked by means of writing
 515  * different patterns to it and reading them back. If the torturing is enabled,
 516  * the physical eraseblock is erased more than once.
 517  *
 518  * This function returns the number of erasures made in case of success, %-EIO
 519  * if the erasure failed or the torturing test failed, and other negative error
 520  * codes in case of other errors. Note, %-EIO means that the physical
 521  * eraseblock is bad.
 522  */
 523 int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
 524 {
 525         int err, ret = 0;
 526
 527         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 528
 529         err = self_check_not_bad(ubi, pnum);
 530         if (err != 0)
 531                 return err;
 532
 533         if (ubi->ro_mode) {
 534                 ubi_err(ubi, "read-only mode");
 535                 return -EROFS;
 536         }
 537
 538         /*
 539          * If the flash is ECC-ed then we have to erase the ECC block before we
 540          * can write to it. But the write is in preparation to an erase in the
 541          * first place. This means we cannot zero out EC and VID before the
 542          * erase and we just have to hope the flash starts erasing from the
 543          * start of the page.
 544          */
 545         if (ubi->nor_flash && ubi->mtd->writesize == 1) {
 546                 err = nor_erase_prepare(ubi, pnum);
 547                 if (err)
 548                         return err;
 549         }
 550
 551         if (torture) {
 552                 ret = torture_peb(ubi, pnum);
 553                 if (ret < 0)
 554                         return ret;
 555         }
 556
 557         err = do_sync_erase(ubi, pnum);
 558         if (err)
 559                 return err;
 560
 561         return ret + 1;
 562 }
 563
 564 /**
 565  * ubi_io_is_bad - check if a physical eraseblock is bad.
 566  * @ubi: UBI device description object
 567  * @pnum: the physical eraseblock number to check
 568  *
 569  * This function returns a positive number if the physical eraseblock is bad,
 570  * zero if not, and a negative error code if an error occurred.
 571  */
 572 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum)
 573 {
 574         struct mtd_info *mtd = ubi->mtd;
 575
 576         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 577
 578         if (ubi->bad_allowed) {
 579                 int ret;
 580
 581                 ret = mtd_block_isbad(mtd, (loff_t)pnum * ubi->peb_size);
 582                 if (ret < 0)
 583                         ubi_err(ubi, "error %d while checking if PEB %d is bad",
 584                                 ret, pnum);
 585                 else if (ret)
 586                         dbg_io("PEB %d is bad", pnum);
 587                 return ret;
 588         }
 589
 590         return 0;
 591 }
 592
 593 /**
 594  * ubi_io_mark_bad - mark a physical eraseblock as bad.
 595  * @ubi: UBI device description object
 596  * @pnum: the physical eraseblock number to mark
 597  *
 598  * This function returns zero in case of success and a negative error code in
 599  * case of failure.
 600  */
 601 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
 602 {
 603         int err;
 604         struct mtd_info *mtd = ubi->mtd;
 605
 606         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 607
 608         if (ubi->ro_mode) {
 609                 ubi_err(ubi, "read-only mode");
 610                 return -EROFS;
 611         }
 612
 613         if (!ubi->bad_allowed)
 614                 return 0;
 615
 616         err = mtd_block_markbad(mtd, (loff_t)pnum * ubi->peb_size);
 617         if (err)
 618                 ubi_err(ubi, "cannot mark PEB %d bad, error %d", pnum, err);
 619         return err;
 620 }
 621
 622 /**
 623  * validate_ec_hdr - validate an erase counter header.
 624  * @ubi: UBI device description object
 625  * @ec_hdr: the erase counter header to check
 626  *
 627  * This function returns zero if the erase counter header is OK, and %1 if
 628  * not.
 629  */
 630 static int validate_ec_hdr(const struct ubi_device *ubi,
 631                            const struct ubi_ec_hdr *ec_hdr)
 632 {
 633         long long ec;
 634         int vid_hdr_offset, leb_start;
 635
 636         ec = be64_to_cpu(ec_hdr->ec);
 637         vid_hdr_offset = be32_to_cpu(ec_hdr->vid_hdr_offset);
 638         leb_start = be32_to_cpu(ec_hdr->data_offset);
 639
 640         if (ec_hdr->version != UBI_VERSION) {
 641                 ubi_err(ubi, "node with incompatible UBI version found: this UBI version is %d, image version is %d",
 642                         UBI_VERSION, (int)ec_hdr->version);
 643                 goto bad;
 644         }
 645
 646         if (vid_hdr_offset != ubi->vid_hdr_offset) {
 647                 ubi_err(ubi, "bad VID header offset %d, expected %d",
 648                         vid_hdr_offset, ubi->vid_hdr_offset);
 649                 goto bad;
 650         }
 651
 652         if (leb_start != ubi->leb_start) {
 653                 ubi_err(ubi, "bad data offset %d, expected %d",
 654                         leb_start, ubi->leb_start);
 655                 goto bad;
 656         }
 657
 658         if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
 659                 ubi_err(ubi, "bad erase counter %lld", ec);
 660                 goto bad;
 661         }
 662
 663         return 0;
 664
 665 bad:
 666         ubi_err(ubi, "bad EC header");
 667         ubi_dump_ec_hdr(ec_hdr);
 668         dump_stack();
 669         return 1;
 670 }
 671
 672 /**
 673  * ubi_io_read_ec_hdr - read and check an erase counter header.
 674  * @ubi: UBI device description object
 675  * @pnum: physical eraseblock to read from
 676  * @ec_hdr: a &struct ubi_ec_hdr object where to store the read erase counter
 677  * header
 678  * @verbose: be verbose if the header is corrupted or was not found
 679  *
 680  * This function reads erase counter header from physical eraseblock @pnum and
 681  * stores it in @ec_hdr. This function also checks CRC checksum of the read
 682  * erase counter header. The following codes may be returned:
 683  *
 684  * o %0 if the CRC checksum is correct and the header was successfully read;
 685  * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 686  *   and corrected by the flash driver; this is harmless but may indicate that
 687  *   this eraseblock may become bad soon (but may be not);
 688  * o %UBI_IO_BAD_HDR if the erase counter header is corrupted (a CRC error);
 689  * o %UBI_IO_BAD_HDR_EBADMSG is the same as %UBI_IO_BAD_HDR, but there also was
 690  *   a data integrity error (uncorrectable ECC error in case of NAND);
 691  * o %UBI_IO_FF if only 0xFF bytes were read (the PEB is supposedly empty)
 692  * o a negative error code in case of failure.
 693  */
 694 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 695                        struct ubi_ec_hdr *ec_hdr, int verbose)
 696 {
 697         int err, read_err;
 698         uint32_t crc, magic, hdr_crc;
 699
 700         dbg_io("read EC header from PEB %d", pnum);
 701         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 702
 703         read_err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
 704         if (read_err) {
 705                 if (read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
 706                         return read_err;
 707
 708                 /*
 709                  * We read all the data, but either a correctable bit-flip
 710                  * occurred, or MTD reported a data integrity error
 711                  * (uncorrectable ECC error in case of NAND). The former is
 712                  * harmless, the later may mean that the read data is
 713                  * corrupted. But we have a CRC check-sum and we will detect
 714                  * this. If the EC header is still OK, we just report this as
 715                  * there was a bit-flip, to force scrubbing.
 716                  */
 717         }
 718
 719         magic = be32_to_cpu(ec_hdr->magic);
 720         if (magic != UBI_EC_HDR_MAGIC) {
 721                 if (mtd_is_eccerr(read_err))
 722                         return UBI_IO_BAD_HDR_EBADMSG;
 723
 724                 /*
 725                  * The magic field is wrong. Let's check if we have read all
 726                  * 0xFF. If yes, this physical eraseblock is assumed to be
 727                  * empty.
 728                  */
 729                 if (ubi_check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
 730                         /* The physical eraseblock is supposedly empty */
 731                         if (verbose)
 732                                 ubi_warn(ubi, "no EC header found at PEB %d, only 0xFF bytes",
 733                                          pnum);
 734                         dbg_bld("no EC header found at PEB %d, only 0xFF bytes",
 735                                 pnum);
 736                         if (!read_err)
 737                                 return UBI_IO_FF;
 738                         else
 739                                 return UBI_IO_FF_BITFLIPS;
 740                 }
 741
 742                 /*
 743                  * This is not a valid erase counter header, and these are not
 744                  * 0xFF bytes. Report that the header is corrupted.
 745                  */
 746                 if (verbose) {
 747                         ubi_warn(ubi, "bad magic number at PEB %d: %08x instead of %08x",
 748                                  pnum, magic, UBI_EC_HDR_MAGIC);
 749                         ubi_dump_ec_hdr(ec_hdr);
 750                 }
 751                 dbg_bld("bad magic number at PEB %d: %08x instead of %08x",
 752                         pnum, magic, UBI_EC_HDR_MAGIC);
 753                 return UBI_IO_BAD_HDR;
 754         }
 755
 756         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 757         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
 758
 759         if (hdr_crc != crc) {
 760                 if (verbose) {
 761                         ubi_warn(ubi, "bad EC header CRC at PEB %d, calculated %#08x, read %#08x",
 762                                  pnum, crc, hdr_crc);
 763                         ubi_dump_ec_hdr(ec_hdr);
 764                 }
 765                 dbg_bld("bad EC header CRC at PEB %d, calculated %#08x, read %#08x",
 766                         pnum, crc, hdr_crc);
 767
 768                 if (!read_err)
 769                         return UBI_IO_BAD_HDR;
 770                 else
 771                         return UBI_IO_BAD_HDR_EBADMSG;
 772         }
 773
 774         /* And of course validate what has just been read from the media */
 775         err = validate_ec_hdr(ubi, ec_hdr);
 776         if (err) {
 777                 ubi_err(ubi, "validation failed for PEB %d", pnum);
 778                 return -EINVAL;
 779         }
 780
 781         /*
 782          * If there was %-EBADMSG, but the header CRC is still OK, report about
 783          * a bit-flip to force scrubbing on this PEB.
 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 = self_check_ec_hdr(ubi, pnum, ec_hdr);
 821         if (err)
 822                 return err;
 823
 824         if (ubi_dbg_power_cut(ubi, POWER_CUT_EC_WRITE))
 825                 return -EROFS;
 826
 827         err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
 828         return err;
 829 }
 830
 831 /**
 832  * validate_vid_hdr - validate a volume identifier header.
 833  * @ubi: UBI device description object
 834  * @vid_hdr: the volume identifier header to check
 835  *
 836  * This function checks that data stored in the volume identifier header
 837  * @vid_hdr. Returns zero if the VID header is OK and %1 if not.
 838  */
 839 static int validate_vid_hdr(const struct ubi_device *ubi,
 840                             const struct ubi_vid_hdr *vid_hdr)
 841 {
 842         int vol_type = vid_hdr->vol_type;
 843         int copy_flag = vid_hdr->copy_flag;
 844         int vol_id = be32_to_cpu(vid_hdr->vol_id);
 845         int lnum = be32_to_cpu(vid_hdr->lnum);
 846         int compat = vid_hdr->compat;
 847         int data_size = be32_to_cpu(vid_hdr->data_size);
 848         int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
 849         int data_pad = be32_to_cpu(vid_hdr->data_pad);
 850         int data_crc = be32_to_cpu(vid_hdr->data_crc);
 851         int usable_leb_size = ubi->leb_size - data_pad;
 852
 853         if (copy_flag != 0 && copy_flag != 1) {
 854                 ubi_err(ubi, "bad copy_flag");
 855                 goto bad;
 856         }
 857
 858         if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
 859             data_pad < 0) {
 860                 ubi_err(ubi, "negative values");
 861                 goto bad;
 862         }
 863
 864         if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
 865                 ubi_err(ubi, "bad vol_id");
 866                 goto bad;
 867         }
 868
 869         if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
 870                 ubi_err(ubi, "bad compat");
 871                 goto bad;
 872         }
 873
 874         if (vol_id >= UBI_INTERNAL_VOL_START && compat != UBI_COMPAT_DELETE &&
 875             compat != UBI_COMPAT_RO && compat != UBI_COMPAT_PRESERVE &&
 876             compat != UBI_COMPAT_REJECT) {
 877                 ubi_err(ubi, "bad compat");
 878                 goto bad;
 879         }
 880
 881         if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
 882                 ubi_err(ubi, "bad vol_type");
 883                 goto bad;
 884         }
 885
 886         if (data_pad >= ubi->leb_size / 2) {
 887                 ubi_err(ubi, "bad data_pad");
 888                 goto bad;
 889         }
 890
 891         if (data_size > ubi->leb_size) {
 892                 ubi_err(ubi, "bad data_size");
 893                 goto bad;
 894         }
 895
 896         if (vol_type == UBI_VID_STATIC) {
 897                 /*
 898                  * Although from high-level point of view static volumes may
 899                  * contain zero bytes of data, but no VID headers can contain
 900                  * zero at these fields, because they empty volumes do not have
 901                  * mapped logical eraseblocks.
 902                  */
 903                 if (used_ebs == 0) {
 904                         ubi_err(ubi, "zero used_ebs");
 905                         goto bad;
 906                 }
 907                 if (data_size == 0) {
 908                         ubi_err(ubi, "zero data_size");
 909                         goto bad;
 910                 }
 911                 if (lnum < used_ebs - 1) {
 912                         if (data_size != usable_leb_size) {
 913                                 ubi_err(ubi, "bad data_size");
 914                                 goto bad;
 915                         }
 916                 } else if (lnum == used_ebs - 1) {
 917                         if (data_size == 0) {
 918                                 ubi_err(ubi, "bad data_size at last LEB");
 919                                 goto bad;
 920                         }
 921                 } else {
 922                         ubi_err(ubi, "too high lnum");
 923                         goto bad;
 924                 }
 925         } else {
 926                 if (copy_flag == 0) {
 927                         if (data_crc != 0) {
 928                                 ubi_err(ubi, "non-zero data CRC");
 929                                 goto bad;
 930                         }
 931                         if (data_size != 0) {
 932                                 ubi_err(ubi, "non-zero data_size");
 933                                 goto bad;
 934                         }
 935                 } else {
 936                         if (data_size == 0) {
 937                                 ubi_err(ubi, "zero data_size of copy");
 938                                 goto bad;
 939                         }
 940                 }
 941                 if (used_ebs != 0) {
 942                         ubi_err(ubi, "bad used_ebs");
 943                         goto bad;
 944                 }
 945         }
 946
 947         return 0;
 948
 949 bad:
 950         ubi_err(ubi, "bad VID header");
 951         ubi_dump_vid_hdr(vid_hdr);
 952         dump_stack();
 953         return 1;
 954 }
 955
 956 /**
 957  * ubi_io_read_vid_hdr - read and check a volume identifier header.
 958  * @ubi: UBI device description object
 959  * @pnum: physical eraseblock number to read from
 960  * @vidb: the volume identifier buffer to store data in
 961  * @verbose: be verbose if the header is corrupted or wasn't found
 962  *
 963  * This function reads the volume identifier header from physical eraseblock
 964  * @pnum and stores it in @vidb. It also checks CRC checksum of the read
 965  * volume identifier header. The error codes are the same as in
 966  * 'ubi_io_read_ec_hdr()'.
 967  *
 968  * Note, the implementation of this function is also very similar to
 969  * 'ubi_io_read_ec_hdr()', so refer commentaries in 'ubi_io_read_ec_hdr()'.
 970  */
 971 int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 972                         struct ubi_vid_io_buf *vidb, int verbose)
 973 {
 974         int err, read_err;
 975         uint32_t crc, magic, hdr_crc;
 976         struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
 977         void *p = vidb->buffer;
 978
 979         dbg_io("read VID header from PEB %d", pnum);
 980         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 981
 982         read_err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
 983                           ubi->vid_hdr_shift + UBI_VID_HDR_SIZE);
 984         if (read_err && read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
 985                 return read_err;
 986
 987         magic = be32_to_cpu(vid_hdr->magic);
 988         if (magic != UBI_VID_HDR_MAGIC) {
 989                 if (mtd_is_eccerr(read_err))
 990                         return UBI_IO_BAD_HDR_EBADMSG;
 991
 992                 if (ubi_check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
 993                         if (verbose)
 994                                 ubi_warn(ubi, "no VID header found at PEB %d, only 0xFF bytes",
 995                                          pnum);
 996                         dbg_bld("no VID header found at PEB %d, only 0xFF bytes",
 997                                 pnum);
 998                         if (!read_err)
 999                                 return UBI_IO_FF;
1000                         else
1001                                 return UBI_IO_FF_BITFLIPS;
1002                 }
1003
1004                 if (verbose) {
1005                         ubi_warn(ubi, "bad magic number at PEB %d: %08x instead of %08x",
1006                                  pnum, magic, UBI_VID_HDR_MAGIC);
1007                         ubi_dump_vid_hdr(vid_hdr);
1008                 }
1009                 dbg_bld("bad magic number at PEB %d: %08x instead of %08x",
1010                         pnum, magic, UBI_VID_HDR_MAGIC);
1011                 return UBI_IO_BAD_HDR;
1012         }
1013
1014         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1015         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1016
1017         if (hdr_crc != crc) {
1018                 if (verbose) {
1019                         ubi_warn(ubi, "bad CRC at PEB %d, calculated %#08x, read %#08x",
1020                                  pnum, crc, hdr_crc);
1021                         ubi_dump_vid_hdr(vid_hdr);
1022                 }
1023                 dbg_bld("bad CRC at PEB %d, calculated %#08x, read %#08x",
1024                         pnum, crc, hdr_crc);
1025                 if (!read_err)
1026                         return UBI_IO_BAD_HDR;
1027                 else
1028                         return UBI_IO_BAD_HDR_EBADMSG;
1029         }
1030
1031         err = validate_vid_hdr(ubi, vid_hdr);
1032         if (err) {
1033                 ubi_err(ubi, "validation failed for PEB %d", pnum);
1034                 return -EINVAL;
1035         }
1036
1037         return read_err ? UBI_IO_BITFLIPS : 0;
1038 }
1039
1040 /**
1041  * ubi_io_write_vid_hdr - write a volume identifier header.
1042  * @ubi: UBI device description object
1043  * @pnum: the physical eraseblock number to write to
1044  * @vidb: the volume identifier buffer to write
1045  *
1046  * This function writes the volume identifier header described by @vid_hdr to
1047  * physical eraseblock @pnum. This function automatically fills the
1048  * @vidb->hdr->magic and the @vidb->hdr->version fields, as well as calculates
1049  * header CRC checksum and stores it at vidb->hdr->hdr_crc.
1050  *
1051  * This function returns zero in case of success and a negative error code in
1052  * case of failure. If %-EIO is returned, the physical eraseblock probably went
1053  * bad.
1054  */
1055 int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
1056                          struct ubi_vid_io_buf *vidb)
1057 {
1058         struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
1059         int err;
1060         uint32_t crc;
1061         void *p = vidb->buffer;
1062
1063         dbg_io("write VID header to PEB %d", pnum);
1064         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
1065
1066         err = self_check_peb_ec_hdr(ubi, pnum);
1067         if (err)
1068                 return err;
1069
1070         vid_hdr->magic = cpu_to_be32(UBI_VID_HDR_MAGIC);
1071         vid_hdr->version = UBI_VERSION;
1072         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1073         vid_hdr->hdr_crc = cpu_to_be32(crc);
1074
1075         err = self_check_vid_hdr(ubi, pnum, vid_hdr);
1076         if (err)
1077                 return err;
1078
1079         if (ubi_dbg_power_cut(ubi, POWER_CUT_VID_WRITE))
1080                 return -EROFS;
1081
1082         err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
1083                            ubi->vid_hdr_alsize);
1084         return err;
1085 }
1086
1087 /**
1088  * self_check_not_bad - ensure that a physical eraseblock is not bad.
1089  * @ubi: UBI device description object
1090  * @pnum: physical eraseblock number to check
1091  *
1092  * This function returns zero if the physical eraseblock is good, %-EINVAL if
1093  * it is bad and a negative error code if an error occurred.
1094  */
1095 static int self_check_not_bad(const struct ubi_device *ubi, int pnum)
1096 {
1097         int err;
1098
1099         if (!ubi_dbg_chk_io(ubi))
1100                 return 0;
1101
1102         err = ubi_io_is_bad(ubi, pnum);
1103         if (!err)
1104                 return err;
1105
1106         ubi_err(ubi, "self-check failed for PEB %d", pnum);
1107         dump_stack();
1108         return err > 0 ? -EINVAL : err;
1109 }
1110
1111 /**
1112  * self_check_ec_hdr - check if an erase counter header is all right.
1113  * @ubi: UBI device description object
1114  * @pnum: physical eraseblock number the erase counter header belongs to
1115  * @ec_hdr: the erase counter header to check
1116  *
1117  * This function returns zero if the erase counter header contains valid
1118  * values, and %-EINVAL if not.
1119  */
1120 static int self_check_ec_hdr(const struct ubi_device *ubi, int pnum,
1121                              const struct ubi_ec_hdr *ec_hdr)
1122 {
1123         int err;
1124         uint32_t magic;
1125
1126         if (!ubi_dbg_chk_io(ubi))
1127                 return 0;
1128
1129         magic = be32_to_cpu(ec_hdr->magic);
1130         if (magic != UBI_EC_HDR_MAGIC) {
1131                 ubi_err(ubi, "bad magic %#08x, must be %#08x",
1132                         magic, UBI_EC_HDR_MAGIC);
1133                 goto fail;
1134         }
1135
1136         err = validate_ec_hdr(ubi, ec_hdr);
1137         if (err) {
1138                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1139                 goto fail;
1140         }
1141
1142         return 0;
1143
1144 fail:
1145         ubi_dump_ec_hdr(ec_hdr);
1146         dump_stack();
1147         return -EINVAL;
1148 }
1149
1150 /**
1151  * self_check_peb_ec_hdr - check erase counter header.
1152  * @ubi: UBI device description object
1153  * @pnum: the physical eraseblock number to check
1154  *
1155  * This function returns zero if the erase counter header is all right and and
1156  * a negative error code if not or if an error occurred.
1157  */
1158 static int self_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
1159 {
1160         int err;
1161         uint32_t crc, hdr_crc;
1162         struct ubi_ec_hdr *ec_hdr;
1163
1164         if (!ubi_dbg_chk_io(ubi))
1165                 return 0;
1166
1167         ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
1168         if (!ec_hdr)
1169                 return -ENOMEM;
1170
1171         err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
1172         if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
1173                 goto exit;
1174
1175         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
1176         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
1177         if (hdr_crc != crc) {
1178                 ubi_err(ubi, "bad CRC, calculated %#08x, read %#08x",
1179                         crc, hdr_crc);
1180                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1181                 ubi_dump_ec_hdr(ec_hdr);
1182                 dump_stack();
1183                 err = -EINVAL;
1184                 goto exit;
1185         }
1186
1187         err = self_check_ec_hdr(ubi, pnum, ec_hdr);
1188
1189 exit:
1190         kfree(ec_hdr);
1191         return err;
1192 }
1193
1194 /**
1195  * self_check_vid_hdr - check that a volume identifier header is all right.
1196  * @ubi: UBI device description object
1197  * @pnum: physical eraseblock number the volume identifier header belongs to
1198  * @vid_hdr: the volume identifier header to check
1199  *
1200  * This function returns zero if the volume identifier header is all right, and
1201  * %-EINVAL if not.
1202  */
1203 static int self_check_vid_hdr(const struct ubi_device *ubi, int pnum,
1204                               const struct ubi_vid_hdr *vid_hdr)
1205 {
1206         int err;
1207         uint32_t magic;
1208
1209         if (!ubi_dbg_chk_io(ubi))
1210                 return 0;
1211
1212         magic = be32_to_cpu(vid_hdr->magic);
1213         if (magic != UBI_VID_HDR_MAGIC) {
1214                 ubi_err(ubi, "bad VID header magic %#08x at PEB %d, must be %#08x",
1215                         magic, pnum, UBI_VID_HDR_MAGIC);
1216                 goto fail;
1217         }
1218
1219         err = validate_vid_hdr(ubi, vid_hdr);
1220         if (err) {
1221                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1222                 goto fail;
1223         }
1224
1225         return err;
1226
1227 fail:
1228         ubi_err(ubi, "self-check failed for PEB %d", pnum);
1229         ubi_dump_vid_hdr(vid_hdr);
1230         dump_stack();
1231         return -EINVAL;
1232
1233 }
1234
1235 /**
1236  * self_check_peb_vid_hdr - check volume identifier header.
1237  * @ubi: UBI device description object
1238  * @pnum: the physical eraseblock number to check
1239  *
1240  * This function returns zero if the volume identifier header is all right,
1241  * and a negative error code if not or if an error occurred.
1242  */
1243 static int self_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
1244 {
1245         int err;
1246         uint32_t crc, hdr_crc;
1247         struct ubi_vid_io_buf *vidb;
1248         struct ubi_vid_hdr *vid_hdr;
1249         void *p;
1250
1251         if (!ubi_dbg_chk_io(ubi))
1252                 return 0;
1253
1254         vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
1255         if (!vidb)
1256                 return -ENOMEM;
1257
1258         vid_hdr = ubi_get_vid_hdr(vidb);
1259         p = vidb->buffer;
1260         err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1261                           ubi->vid_hdr_alsize);
1262         if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
1263                 goto exit;
1264
1265         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1266         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1267         if (hdr_crc != crc) {
1268                 ubi_err(ubi, "bad VID header CRC at PEB %d, calculated %#08x, read %#08x",
1269                         pnum, crc, hdr_crc);
1270                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1271                 ubi_dump_vid_hdr(vid_hdr);
1272                 dump_stack();
1273                 err = -EINVAL;
1274                 goto exit;
1275         }
1276
1277         err = self_check_vid_hdr(ubi, pnum, vid_hdr);
1278
1279 exit:
1280         ubi_free_vid_buf(vidb);
1281         return err;
1282 }
1283
1284 /**
1285  * self_check_write - make sure write succeeded.
1286  * @ubi: UBI device description object
1287  * @buf: buffer with data which were written
1288  * @pnum: physical eraseblock number the data were written to
1289  * @offset: offset within the physical eraseblock the data were written to
1290  * @len: how many bytes were written
1291  *
1292  * This functions reads data which were recently written and compares it with
1293  * the original data buffer - the data have to match. Returns zero if the data
1294  * match and a negative error code if not or in case of failure.
1295  */
1296 static int self_check_write(struct ubi_device *ubi, const void *buf, int pnum,
1297                             int offset, int len)
1298 {
1299         int err, i;
1300         size_t read;
1301         void *buf1;
1302         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1303
1304         if (!ubi_dbg_chk_io(ubi))
1305                 return 0;
1306
1307         buf1 = __vmalloc(len, GFP_NOFS);
1308         if (!buf1) {
1309                 ubi_err(ubi, "cannot allocate memory to check writes");
1310                 return 0;
1311         }
1312
1313         err = mtd_read(ubi->mtd, addr, len, &read, buf1);
1314         if (err && !mtd_is_bitflip(err))
1315                 goto out_free;
1316
1317         for (i = 0; i < len; i++) {
1318                 uint8_t c = ((uint8_t *)buf)[i];
1319                 uint8_t c1 = ((uint8_t *)buf1)[i];
1320                 int dump_len;
1321
1322                 if (c == c1)
1323                         continue;
1324
1325                 ubi_err(ubi, "self-check failed for PEB %d:%d, len %d",
1326                         pnum, offset, len);
1327                 ubi_msg(ubi, "data differ at position %d", i);
1328                 dump_len = max_t(int, 128, len - i);
1329                 ubi_msg(ubi, "hex dump of the original buffer from %d to %d",
1330                         i, i + dump_len);
1331                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1332                                buf + i, dump_len, 1);
1333                 ubi_msg(ubi, "hex dump of the read buffer from %d to %d",
1334                         i, i + dump_len);
1335                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1336                                buf1 + i, dump_len, 1);
1337                 dump_stack();
1338                 err = -EINVAL;
1339                 goto out_free;
1340         }
1341
1342         vfree(buf1);
1343         return 0;
1344
1345 out_free:
1346         vfree(buf1);
1347         return err;
1348 }
1349
1350 /**
1351  * ubi_self_check_all_ff - check that a region of flash is empty.
1352  * @ubi: UBI device description object
1353  * @pnum: the physical eraseblock number to check
1354  * @offset: the starting offset within the physical eraseblock to check
1355  * @len: the length of the region to check
1356  *
1357  * This function returns zero if only 0xFF bytes are present at offset
1358  * @offset of the physical eraseblock @pnum, and a negative error code if not
1359  * or if an error occurred.
1360  */
1361 int ubi_self_check_all_ff(struct ubi_device *ubi, int pnum, int offset, int len)
1362 {
1363         size_t read;
1364         int err;
1365         void *buf;
1366         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1367
1368         if (!ubi_dbg_chk_io(ubi))
1369                 return 0;
1370
1371         buf = __vmalloc(len, GFP_NOFS);
1372         if (!buf) {
1373                 ubi_err(ubi, "cannot allocate memory to check for 0xFFs");
1374                 return 0;
1375         }
1376
1377         err = mtd_read(ubi->mtd, addr, len, &read, buf);
1378         if (err && !mtd_is_bitflip(err)) {
1379                 ubi_err(ubi, "err %d while reading %d bytes from PEB %d:%d, read %zd bytes",
1380                         err, len, pnum, offset, read);
1381                 goto error;
1382         }
1383
1384         err = ubi_check_pattern(buf, 0xFF, len);
1385         if (err == 0) {
1386                 ubi_err(ubi, "flash region at PEB %d:%d, length %d does not contain all 0xFF bytes",
1387                         pnum, offset, len);
1388                 goto fail;
1389         }
1390
1391         vfree(buf);
1392         return 0;
1393
1394 fail:
1395         ubi_err(ubi, "self-check failed for PEB %d", pnum);
1396         ubi_msg(ubi, "hex dump of the %d-%d region", offset, offset + len);
1397         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, buf, len, 1);
1398         err = -EINVAL;
1399 error:
1400         dump_stack();
1401         vfree(buf);
1402         return err;
1403 }