drivers/mtd/ubi/io.c

   1 /*
   2  * Copyright (c) International Business Machines Corp., 2006
   3  * Copyright (c) Nokia Corporation, 2006, 2007
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
  13  * the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  18  *
  19  * Author: Artem Bityutskiy (Битюцкий Артём)
  20  */
  21
  22 /*
  23  * UBI input/output sub-system.
  24  *
  25  * This sub-system provides a uniform way to work with all kinds of the
  26  * underlying MTD devices. It also implements handy functions for reading and
  27  * writing UBI headers.
  28  *
  29  * We are trying to have a paranoid mindset and not to trust to what we read
  30  * from the flash media in order to be more secure and robust. So this
  31  * sub-system validates every single header it reads from the flash media.
  32  *
  33  * Some words about how the eraseblock headers are stored.
  34  *
  35  * The erase counter header is always stored at offset zero. By default, the
  36  * VID header is stored after the EC header at the closest aligned offset
  37  * (i.e. aligned to the minimum I/O unit size). Data starts next to the VID
  38  * header at the closest aligned offset. But this default layout may be
  39  * changed. For example, for different reasons (e.g., optimization) UBI may be
  40  * asked to put the VID header at further offset, and even at an unaligned
  41  * offset. Of course, if the offset of the VID header is unaligned, UBI adds
  42  * proper padding in front of it. Data offset may also be changed but it has to
  43  * be aligned.
  44  *
  45  * About minimal I/O units. In general, UBI assumes flash device model where
  46  * there is only one minimal I/O unit size. E.g., in case of NOR flash it is 1,
  47  * in case of NAND flash it is a NAND page, etc. This is reported by MTD in the
  48  * @ubi->mtd->writesize field. But as an exception, UBI admits use of another
  49  * (smaller) minimal I/O unit size for EC and VID headers to make it possible
  50  * to do different optimizations.
  51  *
  52  * This is extremely useful in case of NAND flashes which admit of several
  53  * write operations to one NAND page. In this case UBI can fit EC and VID
  54  * headers at one NAND page. Thus, UBI may use "sub-page" size as the minimal
  55  * I/O unit for the headers (the @ubi->hdrs_min_io_size field). But it still
  56  * reports NAND page size (@ubi->min_io_size) as a minimal I/O unit for the UBI
  57  * users.
  58  *
  59  * Example: some Samsung NANDs with 2KiB pages allow 4x 512-byte writes, so
  60  * although the minimal I/O unit is 2K, UBI uses 512 bytes for EC and VID
  61  * headers.
  62  *
  63  * Q: why not just to treat sub-page as a minimal I/O unit of this flash
  64  * device, e.g., make @ubi->min_io_size = 512 in the example above?
  65  *
  66  * A: because when writing a sub-page, MTD still writes a full 2K page but the
  67  * bytes which are not relevant to the sub-page are 0xFF. So, basically,
  68  * writing 4x512 sub-pages is 4 times slower than writing one 2KiB NAND page.
  69  * Thus, we prefer to use sub-pages only for EC and VID headers.
  70  *
  71  * As it was noted above, the VID header may start at a non-aligned offset.
  72  * For example, in case of a 2KiB page NAND flash with a 512 bytes sub-page,
  73  * the VID header may reside at offset 1984 which is the last 64 bytes of the
  74  * last sub-page (EC header is always at offset zero). This causes some
  75  * difficulties when reading and writing VID headers.
  76  *
  77  * Suppose we have a 64-byte buffer and we read a VID header at it. We change
  78  * the data and want to write this VID header out. As we can only write in
  79  * 512-byte chunks, we have to allocate one more buffer and copy our VID header
  80  * to offset 448 of this buffer.
  81  *
  82  * The I/O sub-system does the following trick in order to avoid this extra
  83  * copy. It always allocates a @ubi->vid_hdr_alsize bytes buffer for the VID
  84  * header and returns a pointer to offset @ubi->vid_hdr_shift of this buffer.
  85  * When the VID header is being written out, it shifts the VID header pointer
  86  * back and writes the whole sub-page.
  87  */
  88
  89 #include <linux/crc32.h>
  90 #include <linux/err.h>
  91 #include <linux/slab.h>
  92 #include "ubi.h"
  93
  94 static int self_check_not_bad(const struct ubi_device *ubi, int pnum);
  95 static int self_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum);
  96 static int self_check_ec_hdr(const struct ubi_device *ubi, int pnum,
  97                              const struct ubi_ec_hdr *ec_hdr);
  98 static int self_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum);
  99 static int self_check_vid_hdr(const struct ubi_device *ubi, int pnum,
 100                               const struct ubi_vid_hdr *vid_hdr);
 101 static int self_check_write(struct ubi_device *ubi, const void *buf, int pnum,
 102                             int offset, int len);
 103
 104 /**
 105  * ubi_io_read - read data from a physical eraseblock.
 106  * @ubi: UBI device description object
 107  * @buf: buffer where to store the read data
 108  * @pnum: physical eraseblock number to read from
 109  * @offset: offset within the physical eraseblock from where to read
 110  * @len: how many bytes to read
 111  *
 112  * This function reads data from offset @offset of physical eraseblock @pnum
 113  * and stores the read data in the @buf buffer. The following return codes are
 114  * possible:
 115  *
 116  * o %0 if all the requested data were successfully read;
 117  * o %UBI_IO_BITFLIPS if all the requested data were successfully read, but
 118  *   correctable bit-flips were detected; this is harmless but may indicate
 119  *   that this eraseblock may become bad soon (but do not have to);
 120  * o %-EBADMSG if the MTD subsystem reported about data integrity problems, for
 121  *   example it can be an ECC error in case of NAND; this most probably means
 122  *   that the data is corrupted;
 123  * o %-EIO if some I/O error occurred;
 124  * o other negative error codes in case of other errors.
 125  */
 126 int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 127                 int len)
 128 {
 129         int err, retries = 0;
 130         size_t read;
 131         loff_t addr;
 132
 133         dbg_io("read %d bytes from PEB %d:%d", len, pnum, offset);
 134
 135         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 136         ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 137         ubi_assert(len > 0);
 138
 139         err = self_check_not_bad(ubi, pnum);
 140         if (err)
 141                 return err;
 142
 143         /*
 144          * Deliberately corrupt the buffer to improve robustness. Indeed, if we
 145          * do not do this, the following may happen:
 146          * 1. The buffer contains data from previous operation, e.g., read from
 147          *    another PEB previously. The data looks like expected, e.g., if we
 148          *    just do not read anything and return - the caller would not
 149          *    notice this. E.g., if we are reading a VID header, the buffer may
 150          *    contain a valid VID header from another PEB.
 151          * 2. The driver is buggy and returns us success or -EBADMSG or
 152          *    -EUCLEAN, but it does not actually put any data to the buffer.
 153          *
 154          * This may confuse UBI or upper layers - they may think the buffer
 155          * contains valid data while in fact it is just old data. This is
 156          * especially possible because UBI (and UBIFS) relies on CRC, and
 157          * treats data as correct even in case of ECC errors if the CRC is
 158          * correct.
 159          *
 160          * Try to prevent this situation by changing the first byte of the
 161          * buffer.
 162          */
 163         *((uint8_t *)buf) ^= 0xFF;
 164
 165         addr = (loff_t)pnum * ubi->peb_size + offset;
 166 retry:
 167         err = mtd_read(ubi->mtd, addr, len, &read, buf);
 168         if (err) {
 169                 const char *errstr = mtd_is_eccerr(err) ? " (ECC error)" : "";
 170
 171                 if (mtd_is_bitflip(err)) {
 172                         /*
 173                          * -EUCLEAN is reported if there was a bit-flip which
 174                          * was corrected, so this is harmless.
 175                          *
 176                          * We do not report about it here unless debugging is
 177                          * enabled. A corresponding message will be printed
 178                          * later, when it is has been scrubbed.
 179                          */
 180                         ubi_msg(ubi, "fixable bit-flip detected at PEB %d",
 181                                 pnum);
 182                         ubi_assert(len == read);
 183                         return UBI_IO_BITFLIPS;
 184                 }
 185
 186                 if (retries++ < UBI_IO_RETRIES) {
 187                         ubi_warn(ubi, "error %d%s while reading %d bytes from PEB %d:%d, read only %zd bytes, retry",
 188                                  err, errstr, len, pnum, offset, read);
 189                         yield();
 190                         goto retry;
 191                 }
 192
 193                 ubi_err(ubi, "error %d%s while reading %d bytes from PEB %d:%d, read %zd bytes",
 194                         err, errstr, len, pnum, offset, read);
 195                 dump_stack();
 196
 197                 /*
 198                  * The driver should never return -EBADMSG if it failed to read
 199                  * all the requested data. But some buggy drivers might do
 200                  * this, so we change it to -EIO.
 201                  */
 202                 if (read != len && mtd_is_eccerr(err)) {
 203                         ubi_assert(0);
 204                         err = -EIO;
 205                 }
 206         } else {
 207                 ubi_assert(len == read);
 208
 209                 if (ubi_dbg_is_bitflip(ubi)) {
 210                         dbg_gen("bit-flip (emulated)");
 211                         err = UBI_IO_BITFLIPS;
 212                 }
 213         }
 214
 215         return err;
 216 }
 217
 218 /**
 219  * ubi_io_write - write data to a physical eraseblock.
 220  * @ubi: UBI device description object
 221  * @buf: buffer with the data to write
 222  * @pnum: physical eraseblock number to write to
 223  * @offset: offset within the physical eraseblock where to write
 224  * @len: how many bytes to write
 225  *
 226  * This function writes @len bytes of data from buffer @buf to offset @offset
 227  * of physical eraseblock @pnum. If all the data were successfully written,
 228  * zero is returned. If an error occurred, this function returns a negative
 229  * error code. If %-EIO is returned, the physical eraseblock most probably went
 230  * bad.
 231  *
 232  * Note, in case of an error, it is possible that something was still written
 233  * to the flash media, but may be some garbage.
 234  */
 235 int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
 236                  int len)
 237 {
 238         int err;
 239         size_t written;
 240         loff_t addr;
 241
 242         dbg_io("write %d bytes to PEB %d:%d", len, pnum, offset);
 243
 244         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 245         ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 246         ubi_assert(offset % ubi->hdrs_min_io_size == 0);
 247         ubi_assert(len > 0 && len % ubi->hdrs_min_io_size == 0);
 248
 249         if (ubi->ro_mode) {
 250                 ubi_err(ubi, "read-only mode");
 251                 return -EROFS;
 252         }
 253
 254         err = self_check_not_bad(ubi, pnum);
 255         if (err)
 256                 return err;
 257
 258         /* The area we are writing to has to contain all 0xFF bytes */
 259         err = ubi_self_check_all_ff(ubi, pnum, offset, len);
 260         if (err)
 261                 return err;
 262
 263         if (offset >= ubi->leb_start) {
 264                 /*
 265                  * We write to the data area of the physical eraseblock. Make
 266                  * sure it has valid EC and VID headers.
 267                  */
 268                 err = self_check_peb_ec_hdr(ubi, pnum);
 269                 if (err)
 270                         return err;
 271                 err = self_check_peb_vid_hdr(ubi, pnum);
 272                 if (err)
 273                         return err;
 274         }
 275
 276         if (ubi_dbg_is_write_failure(ubi)) {
 277                 ubi_err(ubi, "cannot write %d bytes to PEB %d:%d (emulated)",
 278                         len, pnum, offset);
 279                 dump_stack();
 280                 return -EIO;
 281         }
 282
 283         addr = (loff_t)pnum * ubi->peb_size + offset;
 284         err = mtd_write(ubi->mtd, addr, len, &written, buf);
 285         if (err) {
 286                 ubi_err(ubi, "error %d while writing %d bytes to PEB %d:%d, written %zd bytes",
 287                         err, len, pnum, offset, written);
 288                 dump_stack();
 289                 ubi_dump_flash(ubi, pnum, offset, len);
 290         } else
 291                 ubi_assert(written == len);
 292
 293         if (!err) {
 294                 err = self_check_write(ubi, buf, pnum, offset, len);
 295                 if (err)
 296                         return err;
 297
 298                 /*
 299                  * Since we always write sequentially, the rest of the PEB has
 300                  * to contain only 0xFF bytes.
 301                  */
 302                 offset += len;
 303                 len = ubi->peb_size - offset;
 304                 if (len)
 305                         err = ubi_self_check_all_ff(ubi, pnum, offset, len);
 306         }
 307
 308         return err;
 309 }
 310
 311 /**
 312  * erase_callback - MTD erasure call-back.
 313  * @ei: MTD erase information object.
 314  *
 315  * Note, even though MTD erase interface is asynchronous, all the current
 316  * implementations are synchronous anyway.
 317  */
 318 static void erase_callback(struct erase_info *ei)
 319 {
 320         wake_up_interruptible((wait_queue_head_t *)ei->priv);
 321 }
 322
 323 /**
 324  * do_sync_erase - synchronously erase a physical eraseblock.
 325  * @ubi: UBI device description object
 326  * @pnum: the physical eraseblock number to erase
 327  *
 328  * This function synchronously erases physical eraseblock @pnum and returns
 329  * zero in case of success and a negative error code in case of failure. If
 330  * %-EIO is returned, the physical eraseblock most probably went bad.
 331  */
 332 static int do_sync_erase(struct ubi_device *ubi, int pnum)
 333 {
 334         int err, retries = 0;
 335         struct erase_info ei;
 336         wait_queue_head_t wq;
 337
 338         dbg_io("erase PEB %d", pnum);
 339         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 340
 341         if (ubi->ro_mode) {
 342                 ubi_err(ubi, "read-only mode");
 343                 return -EROFS;
 344         }
 345
 346 retry:
 347         init_waitqueue_head(&wq);
 348         memset(&ei, 0, sizeof(struct erase_info));
 349
 350         ei.mtd      = ubi->mtd;
 351         ei.addr     = (loff_t)pnum * ubi->peb_size;
 352         ei.len      = ubi->peb_size;
 353         ei.callback = erase_callback;
 354         ei.priv     = (unsigned long)&wq;
 355
 356         err = mtd_erase(ubi->mtd, &ei);
 357         if (err) {
 358                 if (retries++ < UBI_IO_RETRIES) {
 359                         ubi_warn(ubi, "error %d while erasing PEB %d, retry",
 360                                  err, pnum);
 361                         yield();
 362                         goto retry;
 363                 }
 364                 ubi_err(ubi, "cannot erase PEB %d, error %d", pnum, err);
 365                 dump_stack();
 366                 return err;
 367         }
 368
 369         err = wait_event_interruptible(wq, ei.state == MTD_ERASE_DONE ||
 370                                            ei.state == MTD_ERASE_FAILED);
 371         if (err) {
 372                 ubi_err(ubi, "interrupted PEB %d erasure", pnum);
 373                 return -EINTR;
 374         }
 375
 376         if (ei.state == MTD_ERASE_FAILED) {
 377                 if (retries++ < UBI_IO_RETRIES) {
 378                         ubi_warn(ubi, "error while erasing PEB %d, retry",
 379                                  pnum);
 380                         yield();
 381                         goto retry;
 382                 }
 383                 ubi_err(ubi, "cannot erase PEB %d", pnum);
 384                 dump_stack();
 385                 return -EIO;
 386         }
 387
 388         err = ubi_self_check_all_ff(ubi, pnum, 0, ubi->peb_size);
 389         if (err)
 390                 return err;
 391
 392         if (ubi_dbg_is_erase_failure(ubi)) {
 393                 ubi_err(ubi, "cannot erase PEB %d (emulated)", pnum);
 394                 return -EIO;
 395         }
 396
 397         return 0;
 398 }
 399
 400 /* Patterns to write to a physical eraseblock when torturing it */
 401 static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
 402
 403 /**
 404  * torture_peb - test a supposedly bad physical eraseblock.
 405  * @ubi: UBI device description object
 406  * @pnum: the physical eraseblock number to test
 407  *
 408  * This function returns %-EIO if the physical eraseblock did not pass the
 409  * test, a positive number of erase operations done if the test was
 410  * successfully passed, and other negative error codes in case of other errors.
 411  */
 412 static int torture_peb(struct ubi_device *ubi, int pnum)
 413 {
 414         int err, i, patt_count;
 415
 416         ubi_msg(ubi, "run torture test for PEB %d", pnum);
 417         patt_count = ARRAY_SIZE(patterns);
 418         ubi_assert(patt_count > 0);
 419
 420         mutex_lock(&ubi->buf_mutex);
 421         for (i = 0; i < patt_count; i++) {
 422                 err = do_sync_erase(ubi, pnum);
 423                 if (err)
 424                         goto out;
 425
 426                 /* Make sure the PEB contains only 0xFF bytes */
 427                 err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 428                 if (err)
 429                         goto out;
 430
 431                 err = ubi_check_pattern(ubi->peb_buf, 0xFF, ubi->peb_size);
 432                 if (err == 0) {
 433                         ubi_err(ubi, "erased PEB %d, but a non-0xFF byte found",
 434                                 pnum);
 435                         err = -EIO;
 436                         goto out;
 437                 }
 438
 439                 /* Write a pattern and check it */
 440                 memset(ubi->peb_buf, patterns[i], ubi->peb_size);
 441                 err = ubi_io_write(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 442                 if (err)
 443                         goto out;
 444
 445                 memset(ubi->peb_buf, ~patterns[i], ubi->peb_size);
 446                 err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 447                 if (err)
 448                         goto out;
 449
 450                 err = ubi_check_pattern(ubi->peb_buf, patterns[i],
 451                                         ubi->peb_size);
 452                 if (err == 0) {
 453                         ubi_err(ubi, "pattern %x checking failed for PEB %d",
 454                                 patterns[i], pnum);
 455                         err = -EIO;
 456                         goto out;
 457                 }
 458         }
 459
 460         err = patt_count;
 461         ubi_msg(ubi, "PEB %d passed torture test, do not mark it as bad", pnum);
 462
 463 out:
 464         mutex_unlock(&ubi->buf_mutex);
 465         if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err)) {
 466                 /*
 467                  * If a bit-flip or data integrity error was detected, the test
 468                  * has not passed because it happened on a freshly erased
 469                  * physical eraseblock which means something is wrong with it.
 470                  */
 471                 ubi_err(ubi, "read problems on freshly erased PEB %d, must be bad",
 472                         pnum);
 473                 err = -EIO;
 474         }
 475         return err;
 476 }
 477
 478 /**
 479  * nor_erase_prepare - prepare a NOR flash PEB for erasure.
 480  * @ubi: UBI device description object
 481  * @pnum: physical eraseblock number to prepare
 482  *
 483  * NOR flash, or at least some of them, have peculiar embedded PEB erasure
 484  * algorithm: the PEB is first filled with zeroes, then it is erased. And
 485  * filling with zeroes starts from the end of the PEB. This was observed with
 486  * Spansion S29GL512N NOR flash.
 487  *
 488  * This means that in case of a power cut we may end up with intact data at the
 489  * beginning of the PEB, and all zeroes at the end of PEB. In other words, the
 490  * EC and VID headers are OK, but a large chunk of data at the end of PEB is
 491  * zeroed. This makes UBI mistakenly treat this PEB as used and associate it
 492  * with an LEB, which leads to subsequent failures (e.g., UBIFS fails).
 493  *
 494  * This function is called before erasing NOR PEBs and it zeroes out EC and VID
 495  * magic numbers in order to invalidate them and prevent the failures. Returns
 496  * zero in case of success and a negative error code in case of failure.
 497  */
 498 static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 499 {
 500         int err;
 501         size_t written;
 502         loff_t addr;
 503         uint32_t data = 0;
 504         struct ubi_ec_hdr ec_hdr;
 505         struct ubi_vid_io_buf vidb;
 506
 507         /*
 508          * Note, we cannot generally define VID header buffers on stack,
 509          * because of the way we deal with these buffers (see the header
 510          * comment in this file). But we know this is a NOR-specific piece of
 511          * code, so we can do this. But yes, this is error-prone and we should
 512          * (pre-)allocate VID header buffer instead.
 513          */
 514         struct ubi_vid_hdr vid_hdr;
 515
 516         /*
 517          * If VID or EC is valid, we have to corrupt them before erasing.
 518          * It is important to first invalidate the EC header, and then the VID
 519          * header. Otherwise a power cut may lead to valid EC header and
 520          * invalid VID header, in which case UBI will treat this PEB as
 521          * corrupted and will try to preserve it, and print scary warnings.
 522          */
 523         addr = (loff_t)pnum * ubi->peb_size;
 524         err = ubi_io_read_ec_hdr(ubi, pnum, &ec_hdr, 0);
 525         if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
 526             err != UBI_IO_FF){
 527                 err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
 528                 if(err)
 529                         goto error;
 530         }
 531
 532         ubi_init_vid_buf(ubi, &vidb, &vid_hdr);
 533         ubi_assert(&vid_hdr == ubi_get_vid_hdr(&vidb));
 534
 535         err = ubi_io_read_vid_hdr(ubi, pnum, &vidb, 0);
 536         if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
 537             err != UBI_IO_FF){
 538                 addr += ubi->vid_hdr_aloffset;
 539                 err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
 540                 if (err)
 541                         goto error;
 542         }
 543         return 0;
 544
 545 error:
 546         /*
 547          * The PEB contains a valid VID or EC header, but we cannot invalidate
 548          * it. Supposedly the flash media or the driver is screwed up, so
 549          * return an error.
 550          */
 551         ubi_err(ubi, "cannot invalidate PEB %d, write returned %d", pnum, err);
 552         ubi_dump_flash(ubi, pnum, 0, ubi->peb_size);
 553         return -EIO;
 554 }
 555
 556 /**
 557  * ubi_io_sync_erase - synchronously erase a physical eraseblock.
 558  * @ubi: UBI device description object
 559  * @pnum: physical eraseblock number to erase
 560  * @torture: if this physical eraseblock has to be tortured
 561  *
 562  * This function synchronously erases physical eraseblock @pnum. If @torture
 563  * flag is not zero, the physical eraseblock is checked by means of writing
 564  * different patterns to it and reading them back. If the torturing is enabled,
 565  * the physical eraseblock is erased more than once.
 566  *
 567  * This function returns the number of erasures made in case of success, %-EIO
 568  * if the erasure failed or the torturing test failed, and other negative error
 569  * codes in case of other errors. Note, %-EIO means that the physical
 570  * eraseblock is bad.
 571  */
 572 int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
 573 {
 574         int err, ret = 0;
 575
 576         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 577
 578         err = self_check_not_bad(ubi, pnum);
 579         if (err != 0)
 580                 return err;
 581
 582         if (ubi->ro_mode) {
 583                 ubi_err(ubi, "read-only mode");
 584                 return -EROFS;
 585         }
 586
 587         if (ubi->nor_flash) {
 588                 err = nor_erase_prepare(ubi, pnum);
 589                 if (err)
 590                         return err;
 591         }
 592
 593         if (torture) {
 594                 ret = torture_peb(ubi, pnum);
 595                 if (ret < 0)
 596                         return ret;
 597         }
 598
 599         err = do_sync_erase(ubi, pnum);
 600         if (err)
 601                 return err;
 602
 603         return ret + 1;
 604 }
 605
 606 /**
 607  * ubi_io_is_bad - check if a physical eraseblock is bad.
 608  * @ubi: UBI device description object
 609  * @pnum: the physical eraseblock number to check
 610  *
 611  * This function returns a positive number if the physical eraseblock is bad,
 612  * zero if not, and a negative error code if an error occurred.
 613  */
 614 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum)
 615 {
 616         struct mtd_info *mtd = ubi->mtd;
 617
 618         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 619
 620         if (ubi->bad_allowed) {
 621                 int ret;
 622
 623                 ret = mtd_block_isbad(mtd, (loff_t)pnum * ubi->peb_size);
 624                 if (ret < 0)
 625                         ubi_err(ubi, "error %d while checking if PEB %d is bad",
 626                                 ret, pnum);
 627                 else if (ret)
 628                         dbg_io("PEB %d is bad", pnum);
 629                 return ret;
 630         }
 631
 632         return 0;
 633 }
 634
 635 /**
 636  * ubi_io_mark_bad - mark a physical eraseblock as bad.
 637  * @ubi: UBI device description object
 638  * @pnum: the physical eraseblock number to mark
 639  *
 640  * This function returns zero in case of success and a negative error code in
 641  * case of failure.
 642  */
 643 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
 644 {
 645         int err;
 646         struct mtd_info *mtd = ubi->mtd;
 647
 648         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 649
 650         if (ubi->ro_mode) {
 651                 ubi_err(ubi, "read-only mode");
 652                 return -EROFS;
 653         }
 654
 655         if (!ubi->bad_allowed)
 656                 return 0;
 657
 658         err = mtd_block_markbad(mtd, (loff_t)pnum * ubi->peb_size);
 659         if (err)
 660                 ubi_err(ubi, "cannot mark PEB %d bad, error %d", pnum, err);
 661         return err;
 662 }
 663
 664 /**
 665  * validate_ec_hdr - validate an erase counter header.
 666  * @ubi: UBI device description object
 667  * @ec_hdr: the erase counter header to check
 668  *
 669  * This function returns zero if the erase counter header is OK, and %1 if
 670  * not.
 671  */
 672 static int validate_ec_hdr(const struct ubi_device *ubi,
 673                            const struct ubi_ec_hdr *ec_hdr)
 674 {
 675         long long ec;
 676         int vid_hdr_offset, leb_start;
 677
 678         ec = be64_to_cpu(ec_hdr->ec);
 679         vid_hdr_offset = be32_to_cpu(ec_hdr->vid_hdr_offset);
 680         leb_start = be32_to_cpu(ec_hdr->data_offset);
 681
 682         if (ec_hdr->version != UBI_VERSION) {
 683                 ubi_err(ubi, "node with incompatible UBI version found: this UBI version is %d, image version is %d",
 684                         UBI_VERSION, (int)ec_hdr->version);
 685                 goto bad;
 686         }
 687
 688         if (vid_hdr_offset != ubi->vid_hdr_offset) {
 689                 ubi_err(ubi, "bad VID header offset %d, expected %d",
 690                         vid_hdr_offset, ubi->vid_hdr_offset);
 691                 goto bad;
 692         }
 693
 694         if (leb_start != ubi->leb_start) {
 695                 ubi_err(ubi, "bad data offset %d, expected %d",
 696                         leb_start, ubi->leb_start);
 697                 goto bad;
 698         }
 699
 700         if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
 701                 ubi_err(ubi, "bad erase counter %lld", ec);
 702                 goto bad;
 703         }
 704
 705         return 0;
 706
 707 bad:
 708         ubi_err(ubi, "bad EC header");
 709         ubi_dump_ec_hdr(ec_hdr);
 710         dump_stack();
 711         return 1;
 712 }
 713
 714 /**
 715  * ubi_io_read_ec_hdr - read and check an erase counter header.
 716  * @ubi: UBI device description object
 717  * @pnum: physical eraseblock to read from
 718  * @ec_hdr: a &struct ubi_ec_hdr object where to store the read erase counter
 719  * header
 720  * @verbose: be verbose if the header is corrupted or was not found
 721  *
 722  * This function reads erase counter header from physical eraseblock @pnum and
 723  * stores it in @ec_hdr. This function also checks CRC checksum of the read
 724  * erase counter header. The following codes may be returned:
 725  *
 726  * o %0 if the CRC checksum is correct and the header was successfully read;
 727  * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 728  *   and corrected by the flash driver; this is harmless but may indicate that
 729  *   this eraseblock may become bad soon (but may be not);
 730  * o %UBI_IO_BAD_HDR if the erase counter header is corrupted (a CRC error);
 731  * o %UBI_IO_BAD_HDR_EBADMSG is the same as %UBI_IO_BAD_HDR, but there also was
 732  *   a data integrity error (uncorrectable ECC error in case of NAND);
 733  * o %UBI_IO_FF if only 0xFF bytes were read (the PEB is supposedly empty)
 734  * o a negative error code in case of failure.
 735  */
 736 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 737                        struct ubi_ec_hdr *ec_hdr, int verbose)
 738 {
 739         int err, read_err;
 740         uint32_t crc, magic, hdr_crc;
 741
 742         dbg_io("read EC header from PEB %d", pnum);
 743         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 744
 745         read_err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
 746         if (read_err) {
 747                 if (read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
 748                         return read_err;
 749
 750                 /*
 751                  * We read all the data, but either a correctable bit-flip
 752                  * occurred, or MTD reported a data integrity error
 753                  * (uncorrectable ECC error in case of NAND). The former is
 754                  * harmless, the later may mean that the read data is
 755                  * corrupted. But we have a CRC check-sum and we will detect
 756                  * this. If the EC header is still OK, we just report this as
 757                  * there was a bit-flip, to force scrubbing.
 758                  */
 759         }
 760
 761         magic = be32_to_cpu(ec_hdr->magic);
 762         if (magic != UBI_EC_HDR_MAGIC) {
 763                 if (mtd_is_eccerr(read_err))
 764                         return UBI_IO_BAD_HDR_EBADMSG;
 765
 766                 /*
 767                  * The magic field is wrong. Let's check if we have read all
 768                  * 0xFF. If yes, this physical eraseblock is assumed to be
 769                  * empty.
 770                  */
 771                 if (ubi_check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
 772                         /* The physical eraseblock is supposedly empty */
 773                         if (verbose)
 774                                 ubi_warn(ubi, "no EC header found at PEB %d, only 0xFF bytes",
 775                                          pnum);
 776                         dbg_bld("no EC header found at PEB %d, only 0xFF bytes",
 777                                 pnum);
 778                         if (!read_err)
 779                                 return UBI_IO_FF;
 780                         else
 781                                 return UBI_IO_FF_BITFLIPS;
 782                 }
 783
 784                 /*
 785                  * This is not a valid erase counter header, and these are not
 786                  * 0xFF bytes. Report that the header is corrupted.
 787                  */
 788                 if (verbose) {
 789                         ubi_warn(ubi, "bad magic number at PEB %d: %08x instead of %08x",
 790                                  pnum, magic, UBI_EC_HDR_MAGIC);
 791                         ubi_dump_ec_hdr(ec_hdr);
 792                 }
 793                 dbg_bld("bad magic number at PEB %d: %08x instead of %08x",
 794                         pnum, magic, UBI_EC_HDR_MAGIC);
 795                 return UBI_IO_BAD_HDR;
 796         }
 797
 798         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 799         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
 800
 801         if (hdr_crc != crc) {
 802                 if (verbose) {
 803                         ubi_warn(ubi, "bad EC header CRC at PEB %d, calculated %#08x, read %#08x",
 804                                  pnum, crc, hdr_crc);
 805                         ubi_dump_ec_hdr(ec_hdr);
 806                 }
 807                 dbg_bld("bad EC header CRC at PEB %d, calculated %#08x, read %#08x",
 808                         pnum, crc, hdr_crc);
 809
 810                 if (!read_err)
 811                         return UBI_IO_BAD_HDR;
 812                 else
 813                         return UBI_IO_BAD_HDR_EBADMSG;
 814         }
 815
 816         /* And of course validate what has just been read from the media */
 817         err = validate_ec_hdr(ubi, ec_hdr);
 818         if (err) {
 819                 ubi_err(ubi, "validation failed for PEB %d", pnum);
 820                 return -EINVAL;
 821         }
 822
 823         /*
 824          * If there was %-EBADMSG, but the header CRC is still OK, report about
 825          * a bit-flip to force scrubbing on this PEB.
 826          */
 827         return read_err ? UBI_IO_BITFLIPS : 0;
 828 }
 829
 830 /**
 831  * ubi_io_write_ec_hdr - write an erase counter header.
 832  * @ubi: UBI device description object
 833  * @pnum: physical eraseblock to write to
 834  * @ec_hdr: the erase counter header to write
 835  *
 836  * This function writes erase counter header described by @ec_hdr to physical
 837  * eraseblock @pnum. It also fills most fields of @ec_hdr before writing, so
 838  * the caller do not have to fill them. Callers must only fill the @ec_hdr->ec
 839  * field.
 840  *
 841  * This function returns zero in case of success and a negative error code in
 842  * case of failure. If %-EIO is returned, the physical eraseblock most probably
 843  * went bad.
 844  */
 845 int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 846                         struct ubi_ec_hdr *ec_hdr)
 847 {
 848         int err;
 849         uint32_t crc;
 850
 851         dbg_io("write EC header to PEB %d", pnum);
 852         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 853
 854         ec_hdr->magic = cpu_to_be32(UBI_EC_HDR_MAGIC);
 855         ec_hdr->version = UBI_VERSION;
 856         ec_hdr->vid_hdr_offset = cpu_to_be32(ubi->vid_hdr_offset);
 857         ec_hdr->data_offset = cpu_to_be32(ubi->leb_start);
 858         ec_hdr->image_seq = cpu_to_be32(ubi->image_seq);
 859         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 860         ec_hdr->hdr_crc = cpu_to_be32(crc);
 861
 862         err = self_check_ec_hdr(ubi, pnum, ec_hdr);
 863         if (err)
 864                 return err;
 865
 866         if (ubi_dbg_power_cut(ubi, POWER_CUT_EC_WRITE))
 867                 return -EROFS;
 868
 869         err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
 870         return err;
 871 }
 872
 873 /**
 874  * validate_vid_hdr - validate a volume identifier header.
 875  * @ubi: UBI device description object
 876  * @vid_hdr: the volume identifier header to check
 877  *
 878  * This function checks that data stored in the volume identifier header
 879  * @vid_hdr. Returns zero if the VID header is OK and %1 if not.
 880  */
 881 static int validate_vid_hdr(const struct ubi_device *ubi,
 882                             const struct ubi_vid_hdr *vid_hdr)
 883 {
 884         int vol_type = vid_hdr->vol_type;
 885         int copy_flag = vid_hdr->copy_flag;
 886         int vol_id = be32_to_cpu(vid_hdr->vol_id);
 887         int lnum = be32_to_cpu(vid_hdr->lnum);
 888         int compat = vid_hdr->compat;
 889         int data_size = be32_to_cpu(vid_hdr->data_size);
 890         int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
 891         int data_pad = be32_to_cpu(vid_hdr->data_pad);
 892         int data_crc = be32_to_cpu(vid_hdr->data_crc);
 893         int usable_leb_size = ubi->leb_size - data_pad;
 894
 895         if (copy_flag != 0 && copy_flag != 1) {
 896                 ubi_err(ubi, "bad copy_flag");
 897                 goto bad;
 898         }
 899
 900         if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
 901             data_pad < 0) {
 902                 ubi_err(ubi, "negative values");
 903                 goto bad;
 904         }
 905
 906         if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
 907                 ubi_err(ubi, "bad vol_id");
 908                 goto bad;
 909         }
 910
 911         if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
 912                 ubi_err(ubi, "bad compat");
 913                 goto bad;
 914         }
 915
 916         if (vol_id >= UBI_INTERNAL_VOL_START && compat != UBI_COMPAT_DELETE &&
 917             compat != UBI_COMPAT_RO && compat != UBI_COMPAT_PRESERVE &&
 918             compat != UBI_COMPAT_REJECT) {
 919                 ubi_err(ubi, "bad compat");
 920                 goto bad;
 921         }
 922
 923         if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
 924                 ubi_err(ubi, "bad vol_type");
 925                 goto bad;
 926         }
 927
 928         if (data_pad >= ubi->leb_size / 2) {
 929                 ubi_err(ubi, "bad data_pad");
 930                 goto bad;
 931         }
 932
 933         if (data_size > ubi->leb_size) {
 934                 ubi_err(ubi, "bad data_size");
 935                 goto bad;
 936         }
 937
 938         if (vol_type == UBI_VID_STATIC) {
 939                 /*
 940                  * Although from high-level point of view static volumes may
 941                  * contain zero bytes of data, but no VID headers can contain
 942                  * zero at these fields, because they empty volumes do not have
 943                  * mapped logical eraseblocks.
 944                  */
 945                 if (used_ebs == 0) {
 946                         ubi_err(ubi, "zero used_ebs");
 947                         goto bad;
 948                 }
 949                 if (data_size == 0) {
 950                         ubi_err(ubi, "zero data_size");
 951                         goto bad;
 952                 }
 953                 if (lnum < used_ebs - 1) {
 954                         if (data_size != usable_leb_size) {
 955                                 ubi_err(ubi, "bad data_size");
 956                                 goto bad;
 957                         }
 958                 } else if (lnum == used_ebs - 1) {
 959                         if (data_size == 0) {
 960                                 ubi_err(ubi, "bad data_size at last LEB");
 961                                 goto bad;
 962                         }
 963                 } else {
 964                         ubi_err(ubi, "too high lnum");
 965                         goto bad;
 966                 }
 967         } else {
 968                 if (copy_flag == 0) {
 969                         if (data_crc != 0) {
 970                                 ubi_err(ubi, "non-zero data CRC");
 971                                 goto bad;
 972                         }
 973                         if (data_size != 0) {
 974                                 ubi_err(ubi, "non-zero data_size");
 975                                 goto bad;
 976                         }
 977                 } else {
 978                         if (data_size == 0) {
 979                                 ubi_err(ubi, "zero data_size of copy");
 980                                 goto bad;
 981                         }
 982                 }
 983                 if (used_ebs != 0) {
 984                         ubi_err(ubi, "bad used_ebs");
 985                         goto bad;
 986                 }
 987         }
 988
 989         return 0;
 990
 991 bad:
 992         ubi_err(ubi, "bad VID header");
 993         ubi_dump_vid_hdr(vid_hdr);
 994         dump_stack();
 995         return 1;
 996 }
 997
 998 /**
 999  * ubi_io_read_vid_hdr - read and check a volume identifier header.
1000  * @ubi: UBI device description object
1001  * @pnum: physical eraseblock number to read from
1002  * @vidb: the volume identifier buffer to store data in
1003  * @verbose: be verbose if the header is corrupted or wasn't found
1004  *
1005  * This function reads the volume identifier header from physical eraseblock
1006  * @pnum and stores it in @vidb. It also checks CRC checksum of the read
1007  * volume identifier header. The error codes are the same as in
1008  * 'ubi_io_read_ec_hdr()'.
1009  *
1010  * Note, the implementation of this function is also very similar to
1011  * 'ubi_io_read_ec_hdr()', so refer commentaries in 'ubi_io_read_ec_hdr()'.
1012  */
1013 int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
1014                         struct ubi_vid_io_buf *vidb, int verbose)
1015 {
1016         int err, read_err;
1017         uint32_t crc, magic, hdr_crc;
1018         struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
1019         void *p = vidb->buffer;
1020
1021         dbg_io("read VID header from PEB %d", pnum);
1022         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
1023
1024         read_err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1025                           ubi->vid_hdr_shift + UBI_VID_HDR_SIZE);
1026         if (read_err && read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
1027                 return read_err;
1028
1029         magic = be32_to_cpu(vid_hdr->magic);
1030         if (magic != UBI_VID_HDR_MAGIC) {
1031                 if (mtd_is_eccerr(read_err))
1032                         return UBI_IO_BAD_HDR_EBADMSG;
1033
1034                 if (ubi_check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
1035                         if (verbose)
1036                                 ubi_warn(ubi, "no VID header found at PEB %d, only 0xFF bytes",
1037                                          pnum);
1038                         dbg_bld("no VID header found at PEB %d, only 0xFF bytes",
1039                                 pnum);
1040                         if (!read_err)
1041                                 return UBI_IO_FF;
1042                         else
1043                                 return UBI_IO_FF_BITFLIPS;
1044                 }
1045
1046                 if (verbose) {
1047                         ubi_warn(ubi, "bad magic number at PEB %d: %08x instead of %08x",
1048                                  pnum, magic, UBI_VID_HDR_MAGIC);
1049                         ubi_dump_vid_hdr(vid_hdr);
1050                 }
1051                 dbg_bld("bad magic number at PEB %d: %08x instead of %08x",
1052                         pnum, magic, UBI_VID_HDR_MAGIC);
1053                 return UBI_IO_BAD_HDR;
1054         }
1055
1056         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1057         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1058
1059         if (hdr_crc != crc) {
1060                 if (verbose) {
1061                         ubi_warn(ubi, "bad CRC at PEB %d, calculated %#08x, read %#08x",
1062                                  pnum, crc, hdr_crc);
1063                         ubi_dump_vid_hdr(vid_hdr);
1064                 }
1065                 dbg_bld("bad CRC at PEB %d, calculated %#08x, read %#08x",
1066                         pnum, crc, hdr_crc);
1067                 if (!read_err)
1068                         return UBI_IO_BAD_HDR;
1069                 else
1070                         return UBI_IO_BAD_HDR_EBADMSG;
1071         }
1072
1073         err = validate_vid_hdr(ubi, vid_hdr);
1074         if (err) {
1075                 ubi_err(ubi, "validation failed for PEB %d", pnum);
1076                 return -EINVAL;
1077         }
1078
1079         return read_err ? UBI_IO_BITFLIPS : 0;
1080 }
1081
1082 /**
1083  * ubi_io_write_vid_hdr - write a volume identifier header.
1084  * @ubi: UBI device description object
1085  * @pnum: the physical eraseblock number to write to
1086  * @vidb: the volume identifier buffer to write
1087  *
1088  * This function writes the volume identifier header described by @vid_hdr to
1089  * physical eraseblock @pnum. This function automatically fills the
1090  * @vidb->hdr->magic and the @vidb->hdr->version fields, as well as calculates
1091  * header CRC checksum and stores it at vidb->hdr->hdr_crc.
1092  *
1093  * This function returns zero in case of success and a negative error code in
1094  * case of failure. If %-EIO is returned, the physical eraseblock probably went
1095  * bad.
1096  */
1097 int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
1098                          struct ubi_vid_io_buf *vidb)
1099 {
1100         struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
1101         int err;
1102         uint32_t crc;
1103         void *p = vidb->buffer;
1104
1105         dbg_io("write VID header to PEB %d", pnum);
1106         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
1107
1108         err = self_check_peb_ec_hdr(ubi, pnum);
1109         if (err)
1110                 return err;
1111
1112         vid_hdr->magic = cpu_to_be32(UBI_VID_HDR_MAGIC);
1113         vid_hdr->version = UBI_VERSION;
1114         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1115         vid_hdr->hdr_crc = cpu_to_be32(crc);
1116
1117         err = self_check_vid_hdr(ubi, pnum, vid_hdr);
1118         if (err)
1119                 return err;
1120
1121         if (ubi_dbg_power_cut(ubi, POWER_CUT_VID_WRITE))
1122                 return -EROFS;
1123
1124         err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
1125                            ubi->vid_hdr_alsize);
1126         return err;
1127 }
1128
1129 /**
1130  * self_check_not_bad - ensure that a physical eraseblock is not bad.
1131  * @ubi: UBI device description object
1132  * @pnum: physical eraseblock number to check
1133  *
1134  * This function returns zero if the physical eraseblock is good, %-EINVAL if
1135  * it is bad and a negative error code if an error occurred.
1136  */
1137 static int self_check_not_bad(const struct ubi_device *ubi, int pnum)
1138 {
1139         int err;
1140
1141         if (!ubi_dbg_chk_io(ubi))
1142                 return 0;
1143
1144         err = ubi_io_is_bad(ubi, pnum);
1145         if (!err)
1146                 return err;
1147
1148         ubi_err(ubi, "self-check failed for PEB %d", pnum);
1149         dump_stack();
1150         return err > 0 ? -EINVAL : err;
1151 }
1152
1153 /**
1154  * self_check_ec_hdr - check if an erase counter header is all right.
1155  * @ubi: UBI device description object
1156  * @pnum: physical eraseblock number the erase counter header belongs to
1157  * @ec_hdr: the erase counter header to check
1158  *
1159  * This function returns zero if the erase counter header contains valid
1160  * values, and %-EINVAL if not.
1161  */
1162 static int self_check_ec_hdr(const struct ubi_device *ubi, int pnum,
1163                              const struct ubi_ec_hdr *ec_hdr)
1164 {
1165         int err;
1166         uint32_t magic;
1167
1168         if (!ubi_dbg_chk_io(ubi))
1169                 return 0;
1170
1171         magic = be32_to_cpu(ec_hdr->magic);
1172         if (magic != UBI_EC_HDR_MAGIC) {
1173                 ubi_err(ubi, "bad magic %#08x, must be %#08x",
1174                         magic, UBI_EC_HDR_MAGIC);
1175                 goto fail;
1176         }
1177
1178         err = validate_ec_hdr(ubi, ec_hdr);
1179         if (err) {
1180                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1181                 goto fail;
1182         }
1183
1184         return 0;
1185
1186 fail:
1187         ubi_dump_ec_hdr(ec_hdr);
1188         dump_stack();
1189         return -EINVAL;
1190 }
1191
1192 /**
1193  * self_check_peb_ec_hdr - check erase counter header.
1194  * @ubi: UBI device description object
1195  * @pnum: the physical eraseblock number to check
1196  *
1197  * This function returns zero if the erase counter header is all right and and
1198  * a negative error code if not or if an error occurred.
1199  */
1200 static int self_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
1201 {
1202         int err;
1203         uint32_t crc, hdr_crc;
1204         struct ubi_ec_hdr *ec_hdr;
1205
1206         if (!ubi_dbg_chk_io(ubi))
1207                 return 0;
1208
1209         ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
1210         if (!ec_hdr)
1211                 return -ENOMEM;
1212
1213         err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
1214         if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
1215                 goto exit;
1216
1217         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
1218         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
1219         if (hdr_crc != crc) {
1220                 ubi_err(ubi, "bad CRC, calculated %#08x, read %#08x",
1221                         crc, hdr_crc);
1222                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1223                 ubi_dump_ec_hdr(ec_hdr);
1224                 dump_stack();
1225                 err = -EINVAL;
1226                 goto exit;
1227         }
1228
1229         err = self_check_ec_hdr(ubi, pnum, ec_hdr);
1230
1231 exit:
1232         kfree(ec_hdr);
1233         return err;
1234 }
1235
1236 /**
1237  * self_check_vid_hdr - check that a volume identifier header is all right.
1238  * @ubi: UBI device description object
1239  * @pnum: physical eraseblock number the volume identifier header belongs to
1240  * @vid_hdr: the volume identifier header to check
1241  *
1242  * This function returns zero if the volume identifier header is all right, and
1243  * %-EINVAL if not.
1244  */
1245 static int self_check_vid_hdr(const struct ubi_device *ubi, int pnum,
1246                               const struct ubi_vid_hdr *vid_hdr)
1247 {
1248         int err;
1249         uint32_t magic;
1250
1251         if (!ubi_dbg_chk_io(ubi))
1252                 return 0;
1253
1254         magic = be32_to_cpu(vid_hdr->magic);
1255         if (magic != UBI_VID_HDR_MAGIC) {
1256                 ubi_err(ubi, "bad VID header magic %#08x at PEB %d, must be %#08x",
1257                         magic, pnum, UBI_VID_HDR_MAGIC);
1258                 goto fail;
1259         }
1260
1261         err = validate_vid_hdr(ubi, vid_hdr);
1262         if (err) {
1263                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1264                 goto fail;
1265         }
1266
1267         return err;
1268
1269 fail:
1270         ubi_err(ubi, "self-check failed for PEB %d", pnum);
1271         ubi_dump_vid_hdr(vid_hdr);
1272         dump_stack();
1273         return -EINVAL;
1274
1275 }
1276
1277 /**
1278  * self_check_peb_vid_hdr - check volume identifier header.
1279  * @ubi: UBI device description object
1280  * @pnum: the physical eraseblock number to check
1281  *
1282  * This function returns zero if the volume identifier header is all right,
1283  * and a negative error code if not or if an error occurred.
1284  */
1285 static int self_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
1286 {
1287         int err;
1288         uint32_t crc, hdr_crc;
1289         struct ubi_vid_io_buf *vidb;
1290         struct ubi_vid_hdr *vid_hdr;
1291         void *p;
1292
1293         if (!ubi_dbg_chk_io(ubi))
1294                 return 0;
1295
1296         vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
1297         if (!vidb)
1298                 return -ENOMEM;
1299
1300         vid_hdr = ubi_get_vid_hdr(vidb);
1301         p = vidb->buffer;
1302         err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1303                           ubi->vid_hdr_alsize);
1304         if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
1305                 goto exit;
1306
1307         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1308         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1309         if (hdr_crc != crc) {
1310                 ubi_err(ubi, "bad VID header CRC at PEB %d, calculated %#08x, read %#08x",
1311                         pnum, crc, hdr_crc);
1312                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1313                 ubi_dump_vid_hdr(vid_hdr);
1314                 dump_stack();
1315                 err = -EINVAL;
1316                 goto exit;
1317         }
1318
1319         err = self_check_vid_hdr(ubi, pnum, vid_hdr);
1320
1321 exit:
1322         ubi_free_vid_buf(vidb);
1323         return err;
1324 }
1325
1326 /**
1327  * self_check_write - make sure write succeeded.
1328  * @ubi: UBI device description object
1329  * @buf: buffer with data which were written
1330  * @pnum: physical eraseblock number the data were written to
1331  * @offset: offset within the physical eraseblock the data were written to
1332  * @len: how many bytes were written
1333  *
1334  * This functions reads data which were recently written and compares it with
1335  * the original data buffer - the data have to match. Returns zero if the data
1336  * match and a negative error code if not or in case of failure.
1337  */
1338 static int self_check_write(struct ubi_device *ubi, const void *buf, int pnum,
1339                             int offset, int len)
1340 {
1341         int err, i;
1342         size_t read;
1343         void *buf1;
1344         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1345
1346         if (!ubi_dbg_chk_io(ubi))
1347                 return 0;
1348
1349         buf1 = __vmalloc(len, GFP_NOFS, PAGE_KERNEL);
1350         if (!buf1) {
1351                 ubi_err(ubi, "cannot allocate memory to check writes");
1352                 return 0;
1353         }
1354
1355         err = mtd_read(ubi->mtd, addr, len, &read, buf1);
1356         if (err && !mtd_is_bitflip(err))
1357                 goto out_free;
1358
1359         for (i = 0; i < len; i++) {
1360                 uint8_t c = ((uint8_t *)buf)[i];
1361                 uint8_t c1 = ((uint8_t *)buf1)[i];
1362                 int dump_len;
1363
1364                 if (c == c1)
1365                         continue;
1366
1367                 ubi_err(ubi, "self-check failed for PEB %d:%d, len %d",
1368                         pnum, offset, len);
1369                 ubi_msg(ubi, "data differ at position %d", i);
1370                 dump_len = max_t(int, 128, len - i);
1371                 ubi_msg(ubi, "hex dump of the original buffer from %d to %d",
1372                         i, i + dump_len);
1373                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1374                                buf + i, dump_len, 1);
1375                 ubi_msg(ubi, "hex dump of the read buffer from %d to %d",
1376                         i, i + dump_len);
1377                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1378                                buf1 + i, dump_len, 1);
1379                 dump_stack();
1380                 err = -EINVAL;
1381                 goto out_free;
1382         }
1383
1384         vfree(buf1);
1385         return 0;
1386
1387 out_free:
1388         vfree(buf1);
1389         return err;
1390 }
1391
1392 /**
1393  * ubi_self_check_all_ff - check that a region of flash is empty.
1394  * @ubi: UBI device description object
1395  * @pnum: the physical eraseblock number to check
1396  * @offset: the starting offset within the physical eraseblock to check
1397  * @len: the length of the region to check
1398  *
1399  * This function returns zero if only 0xFF bytes are present at offset
1400  * @offset of the physical eraseblock @pnum, and a negative error code if not
1401  * or if an error occurred.
1402  */
1403 int ubi_self_check_all_ff(struct ubi_device *ubi, int pnum, int offset, int len)
1404 {
1405         size_t read;
1406         int err;
1407         void *buf;
1408         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1409
1410         if (!ubi_dbg_chk_io(ubi))
1411                 return 0;
1412
1413         buf = __vmalloc(len, GFP_NOFS, PAGE_KERNEL);
1414         if (!buf) {
1415                 ubi_err(ubi, "cannot allocate memory to check for 0xFFs");
1416                 return 0;
1417         }
1418
1419         err = mtd_read(ubi->mtd, addr, len, &read, buf);
1420         if (err && !mtd_is_bitflip(err)) {
1421                 ubi_err(ubi, "err %d while reading %d bytes from PEB %d:%d, read %zd bytes",
1422                         err, len, pnum, offset, read);
1423                 goto error;
1424         }
1425
1426         err = ubi_check_pattern(buf, 0xFF, len);
1427         if (err == 0) {
1428                 ubi_err(ubi, "flash region at PEB %d:%d, length %d does not contain all 0xFF bytes",
1429                         pnum, offset, len);
1430                 goto fail;
1431         }
1432
1433         vfree(buf);
1434         return 0;
1435
1436 fail:
1437         ubi_err(ubi, "self-check failed for PEB %d", pnum);
1438         ubi_msg(ubi, "hex dump of the %d-%d region", offset, offset + len);
1439         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, buf, len, 1);
1440         err = -EINVAL;
1441 error:
1442         dump_stack();
1443         vfree(buf);
1444         return err;
1445 }