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         if (ubi->nor_flash) {
 539                 err = nor_erase_prepare(ubi, pnum);
 540                 if (err)
 541                         return err;
 542         }
 543
 544         if (torture) {
 545                 ret = torture_peb(ubi, pnum);
 546                 if (ret < 0)
 547                         return ret;
 548         }
 549
 550         err = do_sync_erase(ubi, pnum);
 551         if (err)
 552                 return err;
 553
 554         return ret + 1;
 555 }
 556
 557 /**
 558  * ubi_io_is_bad - check if a physical eraseblock is bad.
 559  * @ubi: UBI device description object
 560  * @pnum: the physical eraseblock number to check
 561  *
 562  * This function returns a positive number if the physical eraseblock is bad,
 563  * zero if not, and a negative error code if an error occurred.
 564  */
 565 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum)
 566 {
 567         struct mtd_info *mtd = ubi->mtd;
 568
 569         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 570
 571         if (ubi->bad_allowed) {
 572                 int ret;
 573
 574                 ret = mtd_block_isbad(mtd, (loff_t)pnum * ubi->peb_size);
 575                 if (ret < 0)
 576                         ubi_err(ubi, "error %d while checking if PEB %d is bad",
 577                                 ret, pnum);
 578                 else if (ret)
 579                         dbg_io("PEB %d is bad", pnum);
 580                 return ret;
 581         }
 582
 583         return 0;
 584 }
 585
 586 /**
 587  * ubi_io_mark_bad - mark a physical eraseblock as bad.
 588  * @ubi: UBI device description object
 589  * @pnum: the physical eraseblock number to mark
 590  *
 591  * This function returns zero in case of success and a negative error code in
 592  * case of failure.
 593  */
 594 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
 595 {
 596         int err;
 597         struct mtd_info *mtd = ubi->mtd;
 598
 599         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 600
 601         if (ubi->ro_mode) {
 602                 ubi_err(ubi, "read-only mode");
 603                 return -EROFS;
 604         }
 605
 606         if (!ubi->bad_allowed)
 607                 return 0;
 608
 609         err = mtd_block_markbad(mtd, (loff_t)pnum * ubi->peb_size);
 610         if (err)
 611                 ubi_err(ubi, "cannot mark PEB %d bad, error %d", pnum, err);
 612         return err;
 613 }
 614
 615 /**
 616  * validate_ec_hdr - validate an erase counter header.
 617  * @ubi: UBI device description object
 618  * @ec_hdr: the erase counter header to check
 619  *
 620  * This function returns zero if the erase counter header is OK, and %1 if
 621  * not.
 622  */
 623 static int validate_ec_hdr(const struct ubi_device *ubi,
 624                            const struct ubi_ec_hdr *ec_hdr)
 625 {
 626         long long ec;
 627         int vid_hdr_offset, leb_start;
 628
 629         ec = be64_to_cpu(ec_hdr->ec);
 630         vid_hdr_offset = be32_to_cpu(ec_hdr->vid_hdr_offset);
 631         leb_start = be32_to_cpu(ec_hdr->data_offset);
 632
 633         if (ec_hdr->version != UBI_VERSION) {
 634                 ubi_err(ubi, "node with incompatible UBI version found: this UBI version is %d, image version is %d",
 635                         UBI_VERSION, (int)ec_hdr->version);
 636                 goto bad;
 637         }
 638
 639         if (vid_hdr_offset != ubi->vid_hdr_offset) {
 640                 ubi_err(ubi, "bad VID header offset %d, expected %d",
 641                         vid_hdr_offset, ubi->vid_hdr_offset);
 642                 goto bad;
 643         }
 644
 645         if (leb_start != ubi->leb_start) {
 646                 ubi_err(ubi, "bad data offset %d, expected %d",
 647                         leb_start, ubi->leb_start);
 648                 goto bad;
 649         }
 650
 651         if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
 652                 ubi_err(ubi, "bad erase counter %lld", ec);
 653                 goto bad;
 654         }
 655
 656         return 0;
 657
 658 bad:
 659         ubi_err(ubi, "bad EC header");
 660         ubi_dump_ec_hdr(ec_hdr);
 661         dump_stack();
 662         return 1;
 663 }
 664
 665 /**
 666  * ubi_io_read_ec_hdr - read and check an erase counter header.
 667  * @ubi: UBI device description object
 668  * @pnum: physical eraseblock to read from
 669  * @ec_hdr: a &struct ubi_ec_hdr object where to store the read erase counter
 670  * header
 671  * @verbose: be verbose if the header is corrupted or was not found
 672  *
 673  * This function reads erase counter header from physical eraseblock @pnum and
 674  * stores it in @ec_hdr. This function also checks CRC checksum of the read
 675  * erase counter header. The following codes may be returned:
 676  *
 677  * o %0 if the CRC checksum is correct and the header was successfully read;
 678  * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 679  *   and corrected by the flash driver; this is harmless but may indicate that
 680  *   this eraseblock may become bad soon (but may be not);
 681  * o %UBI_IO_BAD_HDR if the erase counter header is corrupted (a CRC error);
 682  * o %UBI_IO_BAD_HDR_EBADMSG is the same as %UBI_IO_BAD_HDR, but there also was
 683  *   a data integrity error (uncorrectable ECC error in case of NAND);
 684  * o %UBI_IO_FF if only 0xFF bytes were read (the PEB is supposedly empty)
 685  * o a negative error code in case of failure.
 686  */
 687 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 688                        struct ubi_ec_hdr *ec_hdr, int verbose)
 689 {
 690         int err, read_err;
 691         uint32_t crc, magic, hdr_crc;
 692
 693         dbg_io("read EC header from PEB %d", pnum);
 694         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 695
 696         read_err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
 697         if (read_err) {
 698                 if (read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
 699                         return read_err;
 700
 701                 /*
 702                  * We read all the data, but either a correctable bit-flip
 703                  * occurred, or MTD reported a data integrity error
 704                  * (uncorrectable ECC error in case of NAND). The former is
 705                  * harmless, the later may mean that the read data is
 706                  * corrupted. But we have a CRC check-sum and we will detect
 707                  * this. If the EC header is still OK, we just report this as
 708                  * there was a bit-flip, to force scrubbing.
 709                  */
 710         }
 711
 712         magic = be32_to_cpu(ec_hdr->magic);
 713         if (magic != UBI_EC_HDR_MAGIC) {
 714                 if (mtd_is_eccerr(read_err))
 715                         return UBI_IO_BAD_HDR_EBADMSG;
 716
 717                 /*
 718                  * The magic field is wrong. Let's check if we have read all
 719                  * 0xFF. If yes, this physical eraseblock is assumed to be
 720                  * empty.
 721                  */
 722                 if (ubi_check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
 723                         /* The physical eraseblock is supposedly empty */
 724                         if (verbose)
 725                                 ubi_warn(ubi, "no EC header found at PEB %d, only 0xFF bytes",
 726                                          pnum);
 727                         dbg_bld("no EC header found at PEB %d, only 0xFF bytes",
 728                                 pnum);
 729                         if (!read_err)
 730                                 return UBI_IO_FF;
 731                         else
 732                                 return UBI_IO_FF_BITFLIPS;
 733                 }
 734
 735                 /*
 736                  * This is not a valid erase counter header, and these are not
 737                  * 0xFF bytes. Report that the header is corrupted.
 738                  */
 739                 if (verbose) {
 740                         ubi_warn(ubi, "bad magic number at PEB %d: %08x instead of %08x",
 741                                  pnum, magic, UBI_EC_HDR_MAGIC);
 742                         ubi_dump_ec_hdr(ec_hdr);
 743                 }
 744                 dbg_bld("bad magic number at PEB %d: %08x instead of %08x",
 745                         pnum, magic, UBI_EC_HDR_MAGIC);
 746                 return UBI_IO_BAD_HDR;
 747         }
 748
 749         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 750         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
 751
 752         if (hdr_crc != crc) {
 753                 if (verbose) {
 754                         ubi_warn(ubi, "bad EC header CRC at PEB %d, calculated %#08x, read %#08x",
 755                                  pnum, crc, hdr_crc);
 756                         ubi_dump_ec_hdr(ec_hdr);
 757                 }
 758                 dbg_bld("bad EC header CRC at PEB %d, calculated %#08x, read %#08x",
 759                         pnum, crc, hdr_crc);
 760
 761                 if (!read_err)
 762                         return UBI_IO_BAD_HDR;
 763                 else
 764                         return UBI_IO_BAD_HDR_EBADMSG;
 765         }
 766
 767         /* And of course validate what has just been read from the media */
 768         err = validate_ec_hdr(ubi, ec_hdr);
 769         if (err) {
 770                 ubi_err(ubi, "validation failed for PEB %d", pnum);
 771                 return -EINVAL;
 772         }
 773
 774         /*
 775          * If there was %-EBADMSG, but the header CRC is still OK, report about
 776          * a bit-flip to force scrubbing on this PEB.
 777          */
 778         return read_err ? UBI_IO_BITFLIPS : 0;
 779 }
 780
 781 /**
 782  * ubi_io_write_ec_hdr - write an erase counter header.
 783  * @ubi: UBI device description object
 784  * @pnum: physical eraseblock to write to
 785  * @ec_hdr: the erase counter header to write
 786  *
 787  * This function writes erase counter header described by @ec_hdr to physical
 788  * eraseblock @pnum. It also fills most fields of @ec_hdr before writing, so
 789  * the caller do not have to fill them. Callers must only fill the @ec_hdr->ec
 790  * field.
 791  *
 792  * This function returns zero in case of success and a negative error code in
 793  * case of failure. If %-EIO is returned, the physical eraseblock most probably
 794  * went bad.
 795  */
 796 int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 797                         struct ubi_ec_hdr *ec_hdr)
 798 {
 799         int err;
 800         uint32_t crc;
 801
 802         dbg_io("write EC header to PEB %d", pnum);
 803         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 804
 805         ec_hdr->magic = cpu_to_be32(UBI_EC_HDR_MAGIC);
 806         ec_hdr->version = UBI_VERSION;
 807         ec_hdr->vid_hdr_offset = cpu_to_be32(ubi->vid_hdr_offset);
 808         ec_hdr->data_offset = cpu_to_be32(ubi->leb_start);
 809         ec_hdr->image_seq = cpu_to_be32(ubi->image_seq);
 810         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 811         ec_hdr->hdr_crc = cpu_to_be32(crc);
 812
 813         err = self_check_ec_hdr(ubi, pnum, ec_hdr);
 814         if (err)
 815                 return err;
 816
 817         if (ubi_dbg_power_cut(ubi, POWER_CUT_EC_WRITE))
 818                 return -EROFS;
 819
 820         err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
 821         return err;
 822 }
 823
 824 /**
 825  * validate_vid_hdr - validate a volume identifier header.
 826  * @ubi: UBI device description object
 827  * @vid_hdr: the volume identifier header to check
 828  *
 829  * This function checks that data stored in the volume identifier header
 830  * @vid_hdr. Returns zero if the VID header is OK and %1 if not.
 831  */
 832 static int validate_vid_hdr(const struct ubi_device *ubi,
 833                             const struct ubi_vid_hdr *vid_hdr)
 834 {
 835         int vol_type = vid_hdr->vol_type;
 836         int copy_flag = vid_hdr->copy_flag;
 837         int vol_id = be32_to_cpu(vid_hdr->vol_id);
 838         int lnum = be32_to_cpu(vid_hdr->lnum);
 839         int compat = vid_hdr->compat;
 840         int data_size = be32_to_cpu(vid_hdr->data_size);
 841         int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
 842         int data_pad = be32_to_cpu(vid_hdr->data_pad);
 843         int data_crc = be32_to_cpu(vid_hdr->data_crc);
 844         int usable_leb_size = ubi->leb_size - data_pad;
 845
 846         if (copy_flag != 0 && copy_flag != 1) {
 847                 ubi_err(ubi, "bad copy_flag");
 848                 goto bad;
 849         }
 850
 851         if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
 852             data_pad < 0) {
 853                 ubi_err(ubi, "negative values");
 854                 goto bad;
 855         }
 856
 857         if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
 858                 ubi_err(ubi, "bad vol_id");
 859                 goto bad;
 860         }
 861
 862         if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
 863                 ubi_err(ubi, "bad compat");
 864                 goto bad;
 865         }
 866
 867         if (vol_id >= UBI_INTERNAL_VOL_START && compat != UBI_COMPAT_DELETE &&
 868             compat != UBI_COMPAT_RO && compat != UBI_COMPAT_PRESERVE &&
 869             compat != UBI_COMPAT_REJECT) {
 870                 ubi_err(ubi, "bad compat");
 871                 goto bad;
 872         }
 873
 874         if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
 875                 ubi_err(ubi, "bad vol_type");
 876                 goto bad;
 877         }
 878
 879         if (data_pad >= ubi->leb_size / 2) {
 880                 ubi_err(ubi, "bad data_pad");
 881                 goto bad;
 882         }
 883
 884         if (data_size > ubi->leb_size) {
 885                 ubi_err(ubi, "bad data_size");
 886                 goto bad;
 887         }
 888
 889         if (vol_type == UBI_VID_STATIC) {
 890                 /*
 891                  * Although from high-level point of view static volumes may
 892                  * contain zero bytes of data, but no VID headers can contain
 893                  * zero at these fields, because they empty volumes do not have
 894                  * mapped logical eraseblocks.
 895                  */
 896                 if (used_ebs == 0) {
 897                         ubi_err(ubi, "zero used_ebs");
 898                         goto bad;
 899                 }
 900                 if (data_size == 0) {
 901                         ubi_err(ubi, "zero data_size");
 902                         goto bad;
 903                 }
 904                 if (lnum < used_ebs - 1) {
 905                         if (data_size != usable_leb_size) {
 906                                 ubi_err(ubi, "bad data_size");
 907                                 goto bad;
 908                         }
 909                 } else if (lnum == used_ebs - 1) {
 910                         if (data_size == 0) {
 911                                 ubi_err(ubi, "bad data_size at last LEB");
 912                                 goto bad;
 913                         }
 914                 } else {
 915                         ubi_err(ubi, "too high lnum");
 916                         goto bad;
 917                 }
 918         } else {
 919                 if (copy_flag == 0) {
 920                         if (data_crc != 0) {
 921                                 ubi_err(ubi, "non-zero data CRC");
 922                                 goto bad;
 923                         }
 924                         if (data_size != 0) {
 925                                 ubi_err(ubi, "non-zero data_size");
 926                                 goto bad;
 927                         }
 928                 } else {
 929                         if (data_size == 0) {
 930                                 ubi_err(ubi, "zero data_size of copy");
 931                                 goto bad;
 932                         }
 933                 }
 934                 if (used_ebs != 0) {
 935                         ubi_err(ubi, "bad used_ebs");
 936                         goto bad;
 937                 }
 938         }
 939
 940         return 0;
 941
 942 bad:
 943         ubi_err(ubi, "bad VID header");
 944         ubi_dump_vid_hdr(vid_hdr);
 945         dump_stack();
 946         return 1;
 947 }
 948
 949 /**
 950  * ubi_io_read_vid_hdr - read and check a volume identifier header.
 951  * @ubi: UBI device description object
 952  * @pnum: physical eraseblock number to read from
 953  * @vidb: the volume identifier buffer to store data in
 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 @vidb. It also checks CRC checksum of the read
 958  * volume identifier header. The error codes are the same as in
 959  * 'ubi_io_read_ec_hdr()'.
 960  *
 961  * Note, the implementation of this function is also very similar to
 962  * 'ubi_io_read_ec_hdr()', so refer commentaries in 'ubi_io_read_ec_hdr()'.
 963  */
 964 int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 965                         struct ubi_vid_io_buf *vidb, int verbose)
 966 {
 967         int err, read_err;
 968         uint32_t crc, magic, hdr_crc;
 969         struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
 970         void *p = vidb->buffer;
 971
 972         dbg_io("read VID header from PEB %d", pnum);
 973         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 974
 975         read_err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
 976                           ubi->vid_hdr_shift + UBI_VID_HDR_SIZE);
 977         if (read_err && read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
 978                 return read_err;
 979
 980         magic = be32_to_cpu(vid_hdr->magic);
 981         if (magic != UBI_VID_HDR_MAGIC) {
 982                 if (mtd_is_eccerr(read_err))
 983                         return UBI_IO_BAD_HDR_EBADMSG;
 984
 985                 if (ubi_check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
 986                         if (verbose)
 987                                 ubi_warn(ubi, "no VID header found at PEB %d, only 0xFF bytes",
 988                                          pnum);
 989                         dbg_bld("no VID header found at PEB %d, only 0xFF bytes",
 990                                 pnum);
 991                         if (!read_err)
 992                                 return UBI_IO_FF;
 993                         else
 994                                 return UBI_IO_FF_BITFLIPS;
 995                 }
 996
 997                 if (verbose) {
 998                         ubi_warn(ubi, "bad magic number at PEB %d: %08x instead of %08x",
 999                                  pnum, magic, UBI_VID_HDR_MAGIC);
1000                         ubi_dump_vid_hdr(vid_hdr);
1001                 }
1002                 dbg_bld("bad magic number at PEB %d: %08x instead of %08x",
1003                         pnum, magic, UBI_VID_HDR_MAGIC);
1004                 return UBI_IO_BAD_HDR;
1005         }
1006
1007         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1008         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1009
1010         if (hdr_crc != crc) {
1011                 if (verbose) {
1012                         ubi_warn(ubi, "bad CRC at PEB %d, calculated %#08x, read %#08x",
1013                                  pnum, crc, hdr_crc);
1014                         ubi_dump_vid_hdr(vid_hdr);
1015                 }
1016                 dbg_bld("bad CRC at PEB %d, calculated %#08x, read %#08x",
1017                         pnum, crc, hdr_crc);
1018                 if (!read_err)
1019                         return UBI_IO_BAD_HDR;
1020                 else
1021                         return UBI_IO_BAD_HDR_EBADMSG;
1022         }
1023
1024         err = validate_vid_hdr(ubi, vid_hdr);
1025         if (err) {
1026                 ubi_err(ubi, "validation failed for PEB %d", pnum);
1027                 return -EINVAL;
1028         }
1029
1030         return read_err ? UBI_IO_BITFLIPS : 0;
1031 }
1032
1033 /**
1034  * ubi_io_write_vid_hdr - write a volume identifier header.
1035  * @ubi: UBI device description object
1036  * @pnum: the physical eraseblock number to write to
1037  * @vidb: the volume identifier buffer to write
1038  *
1039  * This function writes the volume identifier header described by @vid_hdr to
1040  * physical eraseblock @pnum. This function automatically fills the
1041  * @vidb->hdr->magic and the @vidb->hdr->version fields, as well as calculates
1042  * header CRC checksum and stores it at vidb->hdr->hdr_crc.
1043  *
1044  * This function returns zero in case of success and a negative error code in
1045  * case of failure. If %-EIO is returned, the physical eraseblock probably went
1046  * bad.
1047  */
1048 int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
1049                          struct ubi_vid_io_buf *vidb)
1050 {
1051         struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
1052         int err;
1053         uint32_t crc;
1054         void *p = vidb->buffer;
1055
1056         dbg_io("write VID header to PEB %d", pnum);
1057         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
1058
1059         err = self_check_peb_ec_hdr(ubi, pnum);
1060         if (err)
1061                 return err;
1062
1063         vid_hdr->magic = cpu_to_be32(UBI_VID_HDR_MAGIC);
1064         vid_hdr->version = UBI_VERSION;
1065         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1066         vid_hdr->hdr_crc = cpu_to_be32(crc);
1067
1068         err = self_check_vid_hdr(ubi, pnum, vid_hdr);
1069         if (err)
1070                 return err;
1071
1072         if (ubi_dbg_power_cut(ubi, POWER_CUT_VID_WRITE))
1073                 return -EROFS;
1074
1075         err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
1076                            ubi->vid_hdr_alsize);
1077         return err;
1078 }
1079
1080 /**
1081  * self_check_not_bad - ensure that a physical eraseblock is not bad.
1082  * @ubi: UBI device description object
1083  * @pnum: physical eraseblock number to check
1084  *
1085  * This function returns zero if the physical eraseblock is good, %-EINVAL if
1086  * it is bad and a negative error code if an error occurred.
1087  */
1088 static int self_check_not_bad(const struct ubi_device *ubi, int pnum)
1089 {
1090         int err;
1091
1092         if (!ubi_dbg_chk_io(ubi))
1093                 return 0;
1094
1095         err = ubi_io_is_bad(ubi, pnum);
1096         if (!err)
1097                 return err;
1098
1099         ubi_err(ubi, "self-check failed for PEB %d", pnum);
1100         dump_stack();
1101         return err > 0 ? -EINVAL : err;
1102 }
1103
1104 /**
1105  * self_check_ec_hdr - check if an erase counter header is all right.
1106  * @ubi: UBI device description object
1107  * @pnum: physical eraseblock number the erase counter header belongs to
1108  * @ec_hdr: the erase counter header to check
1109  *
1110  * This function returns zero if the erase counter header contains valid
1111  * values, and %-EINVAL if not.
1112  */
1113 static int self_check_ec_hdr(const struct ubi_device *ubi, int pnum,
1114                              const struct ubi_ec_hdr *ec_hdr)
1115 {
1116         int err;
1117         uint32_t magic;
1118
1119         if (!ubi_dbg_chk_io(ubi))
1120                 return 0;
1121
1122         magic = be32_to_cpu(ec_hdr->magic);
1123         if (magic != UBI_EC_HDR_MAGIC) {
1124                 ubi_err(ubi, "bad magic %#08x, must be %#08x",
1125                         magic, UBI_EC_HDR_MAGIC);
1126                 goto fail;
1127         }
1128
1129         err = validate_ec_hdr(ubi, ec_hdr);
1130         if (err) {
1131                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1132                 goto fail;
1133         }
1134
1135         return 0;
1136
1137 fail:
1138         ubi_dump_ec_hdr(ec_hdr);
1139         dump_stack();
1140         return -EINVAL;
1141 }
1142
1143 /**
1144  * self_check_peb_ec_hdr - check erase counter header.
1145  * @ubi: UBI device description object
1146  * @pnum: the physical eraseblock number to check
1147  *
1148  * This function returns zero if the erase counter header is all right and and
1149  * a negative error code if not or if an error occurred.
1150  */
1151 static int self_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
1152 {
1153         int err;
1154         uint32_t crc, hdr_crc;
1155         struct ubi_ec_hdr *ec_hdr;
1156
1157         if (!ubi_dbg_chk_io(ubi))
1158                 return 0;
1159
1160         ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
1161         if (!ec_hdr)
1162                 return -ENOMEM;
1163
1164         err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
1165         if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
1166                 goto exit;
1167
1168         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
1169         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
1170         if (hdr_crc != crc) {
1171                 ubi_err(ubi, "bad CRC, calculated %#08x, read %#08x",
1172                         crc, hdr_crc);
1173                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1174                 ubi_dump_ec_hdr(ec_hdr);
1175                 dump_stack();
1176                 err = -EINVAL;
1177                 goto exit;
1178         }
1179
1180         err = self_check_ec_hdr(ubi, pnum, ec_hdr);
1181
1182 exit:
1183         kfree(ec_hdr);
1184         return err;
1185 }
1186
1187 /**
1188  * self_check_vid_hdr - check that a volume identifier header is all right.
1189  * @ubi: UBI device description object
1190  * @pnum: physical eraseblock number the volume identifier header belongs to
1191  * @vid_hdr: the volume identifier header to check
1192  *
1193  * This function returns zero if the volume identifier header is all right, and
1194  * %-EINVAL if not.
1195  */
1196 static int self_check_vid_hdr(const struct ubi_device *ubi, int pnum,
1197                               const struct ubi_vid_hdr *vid_hdr)
1198 {
1199         int err;
1200         uint32_t magic;
1201
1202         if (!ubi_dbg_chk_io(ubi))
1203                 return 0;
1204
1205         magic = be32_to_cpu(vid_hdr->magic);
1206         if (magic != UBI_VID_HDR_MAGIC) {
1207                 ubi_err(ubi, "bad VID header magic %#08x at PEB %d, must be %#08x",
1208                         magic, pnum, UBI_VID_HDR_MAGIC);
1209                 goto fail;
1210         }
1211
1212         err = validate_vid_hdr(ubi, vid_hdr);
1213         if (err) {
1214                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1215                 goto fail;
1216         }
1217
1218         return err;
1219
1220 fail:
1221         ubi_err(ubi, "self-check failed for PEB %d", pnum);
1222         ubi_dump_vid_hdr(vid_hdr);
1223         dump_stack();
1224         return -EINVAL;
1225
1226 }
1227
1228 /**
1229  * self_check_peb_vid_hdr - check volume identifier header.
1230  * @ubi: UBI device description object
1231  * @pnum: the physical eraseblock number to check
1232  *
1233  * This function returns zero if the volume identifier header is all right,
1234  * and a negative error code if not or if an error occurred.
1235  */
1236 static int self_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
1237 {
1238         int err;
1239         uint32_t crc, hdr_crc;
1240         struct ubi_vid_io_buf *vidb;
1241         struct ubi_vid_hdr *vid_hdr;
1242         void *p;
1243
1244         if (!ubi_dbg_chk_io(ubi))
1245                 return 0;
1246
1247         vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
1248         if (!vidb)
1249                 return -ENOMEM;
1250
1251         vid_hdr = ubi_get_vid_hdr(vidb);
1252         p = vidb->buffer;
1253         err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1254                           ubi->vid_hdr_alsize);
1255         if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
1256                 goto exit;
1257
1258         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1259         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1260         if (hdr_crc != crc) {
1261                 ubi_err(ubi, "bad VID header CRC at PEB %d, calculated %#08x, read %#08x",
1262                         pnum, crc, hdr_crc);
1263                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1264                 ubi_dump_vid_hdr(vid_hdr);
1265                 dump_stack();
1266                 err = -EINVAL;
1267                 goto exit;
1268         }
1269
1270         err = self_check_vid_hdr(ubi, pnum, vid_hdr);
1271
1272 exit:
1273         ubi_free_vid_buf(vidb);
1274         return err;
1275 }
1276
1277 /**
1278  * self_check_write - make sure write succeeded.
1279  * @ubi: UBI device description object
1280  * @buf: buffer with data which were written
1281  * @pnum: physical eraseblock number the data were written to
1282  * @offset: offset within the physical eraseblock the data were written to
1283  * @len: how many bytes were written
1284  *
1285  * This functions reads data which were recently written and compares it with
1286  * the original data buffer - the data have to match. Returns zero if the data
1287  * match and a negative error code if not or in case of failure.
1288  */
1289 static int self_check_write(struct ubi_device *ubi, const void *buf, int pnum,
1290                             int offset, int len)
1291 {
1292         int err, i;
1293         size_t read;
1294         void *buf1;
1295         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1296
1297         if (!ubi_dbg_chk_io(ubi))
1298                 return 0;
1299
1300         buf1 = __vmalloc(len, GFP_NOFS, PAGE_KERNEL);
1301         if (!buf1) {
1302                 ubi_err(ubi, "cannot allocate memory to check writes");
1303                 return 0;
1304         }
1305
1306         err = mtd_read(ubi->mtd, addr, len, &read, buf1);
1307         if (err && !mtd_is_bitflip(err))
1308                 goto out_free;
1309
1310         for (i = 0; i < len; i++) {
1311                 uint8_t c = ((uint8_t *)buf)[i];
1312                 uint8_t c1 = ((uint8_t *)buf1)[i];
1313                 int dump_len;
1314
1315                 if (c == c1)
1316                         continue;
1317
1318                 ubi_err(ubi, "self-check failed for PEB %d:%d, len %d",
1319                         pnum, offset, len);
1320                 ubi_msg(ubi, "data differ at position %d", i);
1321                 dump_len = max_t(int, 128, len - i);
1322                 ubi_msg(ubi, "hex dump of the original buffer from %d to %d",
1323                         i, i + dump_len);
1324                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1325                                buf + i, dump_len, 1);
1326                 ubi_msg(ubi, "hex dump of the read buffer from %d to %d",
1327                         i, i + dump_len);
1328                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1329                                buf1 + i, dump_len, 1);
1330                 dump_stack();
1331                 err = -EINVAL;
1332                 goto out_free;
1333         }
1334
1335         vfree(buf1);
1336         return 0;
1337
1338 out_free:
1339         vfree(buf1);
1340         return err;
1341 }
1342
1343 /**
1344  * ubi_self_check_all_ff - check that a region of flash is empty.
1345  * @ubi: UBI device description object
1346  * @pnum: the physical eraseblock number to check
1347  * @offset: the starting offset within the physical eraseblock to check
1348  * @len: the length of the region to check
1349  *
1350  * This function returns zero if only 0xFF bytes are present at offset
1351  * @offset of the physical eraseblock @pnum, and a negative error code if not
1352  * or if an error occurred.
1353  */
1354 int ubi_self_check_all_ff(struct ubi_device *ubi, int pnum, int offset, int len)
1355 {
1356         size_t read;
1357         int err;
1358         void *buf;
1359         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1360
1361         if (!ubi_dbg_chk_io(ubi))
1362                 return 0;
1363
1364         buf = __vmalloc(len, GFP_NOFS, PAGE_KERNEL);
1365         if (!buf) {
1366                 ubi_err(ubi, "cannot allocate memory to check for 0xFFs");
1367                 return 0;
1368         }
1369
1370         err = mtd_read(ubi->mtd, addr, len, &read, buf);
1371         if (err && !mtd_is_bitflip(err)) {
1372                 ubi_err(ubi, "err %d while reading %d bytes from PEB %d:%d, read %zd bytes",
1373                         err, len, pnum, offset, read);
1374                 goto error;
1375         }
1376
1377         err = ubi_check_pattern(buf, 0xFF, len);
1378         if (err == 0) {
1379                 ubi_err(ubi, "flash region at PEB %d:%d, length %d does not contain all 0xFF bytes",
1380                         pnum, offset, len);
1381                 goto fail;
1382         }
1383
1384         vfree(buf);
1385         return 0;
1386
1387 fail:
1388         ubi_err(ubi, "self-check failed for PEB %d", pnum);
1389         ubi_msg(ubi, "hex dump of the %d-%d region", offset, offset + len);
1390         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, buf, len, 1);
1391         err = -EINVAL;
1392 error:
1393         dump_stack();
1394         vfree(buf);
1395         return err;
1396 }