drivers/mtd/ubi/io.c

   1 /*
   2  * Copyright (c) International Business Machines Corp., 2006
   3  * Copyright (c) Nokia Corporation, 2006, 2007
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
  13  * the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  18  *
  19  * Author: Artem Bityutskiy (Битюцкий Артём)
  20  */
  21
  22 /*
  23  * UBI input/output sub-system.
  24  *
  25  * This sub-system provides a uniform way to work with all kinds of the
  26  * underlying MTD devices. It also implements handy functions for reading and
  27  * writing UBI headers.
  28  *
  29  * We are trying to have a paranoid mindset and not to trust to what we read
  30  * from the flash media in order to be more secure and robust. So this
  31  * sub-system validates every single header it reads from the flash media.
  32  *
  33  * Some words about how the eraseblock headers are stored.
  34  *
  35  * The erase counter header is always stored at offset zero. By default, the
  36  * VID header is stored after the EC header at the closest aligned offset
  37  * (i.e. aligned to the minimum I/O unit size). Data starts next to the VID
  38  * header at the closest aligned offset. But this default layout may be
  39  * changed. For example, for different reasons (e.g., optimization) UBI may be
  40  * asked to put the VID header at further offset, and even at an unaligned
  41  * offset. Of course, if the offset of the VID header is unaligned, UBI adds
  42  * proper padding in front of it. Data offset may also be changed but it has to
  43  * be aligned.
  44  *
  45  * About minimal I/O units. In general, UBI assumes flash device model where
  46  * there is only one minimal I/O unit size. E.g., in case of NOR flash it is 1,
  47  * in case of NAND flash it is a NAND page, etc. This is reported by MTD in the
  48  * @ubi->mtd->writesize field. But as an exception, UBI admits of using another
  49  * (smaller) minimal I/O unit size for EC and VID headers to make it possible
  50  * to do different optimizations.
  51  *
  52  * This is extremely useful in case of NAND flashes which admit of several
  53  * write operations to one NAND page. In this case UBI can fit EC and VID
  54  * headers at one NAND page. Thus, UBI may use "sub-page" size as the minimal
  55  * I/O unit for the headers (the @ubi->hdrs_min_io_size field). But it still
  56  * reports NAND page size (@ubi->min_io_size) as a minimal I/O unit for the UBI
  57  * users.
  58  *
  59  * Example: some Samsung NANDs with 2KiB pages allow 4x 512-byte writes, so
  60  * although the minimal I/O unit is 2K, UBI uses 512 bytes for EC and VID
  61  * headers.
  62  *
  63  * Q: why not just to treat sub-page as a minimal I/O unit of this flash
  64  * device, e.g., make @ubi->min_io_size = 512 in the example above?
  65  *
  66  * A: because when writing a sub-page, MTD still writes a full 2K page but the
  67  * bytes which are 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                         dbg_msg("fixable bit-flip detected at PEB %d", pnum);
 181                         ubi_assert(len == read);
 182                         return UBI_IO_BITFLIPS;
 183                 }
 184
 185                 if (retries++ < UBI_IO_RETRIES) {
 186                         ubi_warn("error %d%s while reading %d bytes from PEB "
 187                                  "%d:%d, read only %zd bytes, retry",
 188                                  err, errstr, len, pnum, offset, read);
 189                         yield();
 190                         goto retry;
 191                 }
 192
 193                 ubi_err("error %d%s while reading %d bytes from PEB %d:%d, "
 194                         "read %zd bytes", 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("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("cannot write %d bytes to PEB %d:%d "
 278                         "(emulated)", 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("error %d while writing %d bytes to PEB %d:%d, written "
 287                         "%zd bytes", 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("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("error %d while erasing PEB %d, retry",
 360                                  err, pnum);
 361                         yield();
 362                         goto retry;
 363                 }
 364                 ubi_err("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("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("error while erasing PEB %d, retry", pnum);
 379                         yield();
 380                         goto retry;
 381                 }
 382                 ubi_err("cannot erase PEB %d", pnum);
 383                 dump_stack();
 384                 return -EIO;
 385         }
 386
 387         err = ubi_self_check_all_ff(ubi, pnum, 0, ubi->peb_size);
 388         if (err)
 389                 return err;
 390
 391         if (ubi_dbg_is_erase_failure(ubi)) {
 392                 ubi_err("cannot erase PEB %d (emulated)", pnum);
 393                 return -EIO;
 394         }
 395
 396         return 0;
 397 }
 398
 399 /* Patterns to write to a physical eraseblock when torturing it */
 400 static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
 401
 402 /**
 403  * torture_peb - test a supposedly bad physical eraseblock.
 404  * @ubi: UBI device description object
 405  * @pnum: the physical eraseblock number to test
 406  *
 407  * This function returns %-EIO if the physical eraseblock did not pass the
 408  * test, a positive number of erase operations done if the test was
 409  * successfully passed, and other negative error codes in case of other errors.
 410  */
 411 static int torture_peb(struct ubi_device *ubi, int pnum)
 412 {
 413         int err, i, patt_count;
 414
 415         ubi_msg("run torture test for PEB %d", pnum);
 416         patt_count = ARRAY_SIZE(patterns);
 417         ubi_assert(patt_count > 0);
 418
 419         mutex_lock(&ubi->buf_mutex);
 420         for (i = 0; i < patt_count; i++) {
 421                 err = do_sync_erase(ubi, pnum);
 422                 if (err)
 423                         goto out;
 424
 425                 /* Make sure the PEB contains only 0xFF bytes */
 426                 err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 427                 if (err)
 428                         goto out;
 429
 430                 err = ubi_check_pattern(ubi->peb_buf, 0xFF, ubi->peb_size);
 431                 if (err == 0) {
 432                         ubi_err("erased PEB %d, but a non-0xFF byte found",
 433                                 pnum);
 434                         err = -EIO;
 435                         goto out;
 436                 }
 437
 438                 /* Write a pattern and check it */
 439                 memset(ubi->peb_buf, patterns[i], ubi->peb_size);
 440                 err = ubi_io_write(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 441                 if (err)
 442                         goto out;
 443
 444                 memset(ubi->peb_buf, ~patterns[i], ubi->peb_size);
 445                 err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 446                 if (err)
 447                         goto out;
 448
 449                 err = ubi_check_pattern(ubi->peb_buf, patterns[i],
 450                                         ubi->peb_size);
 451                 if (err == 0) {
 452                         ubi_err("pattern %x checking failed for PEB %d",
 453                                 patterns[i], pnum);
 454                         err = -EIO;
 455                         goto out;
 456                 }
 457         }
 458
 459         err = patt_count;
 460         ubi_msg("PEB %d passed torture test, do not mark it as bad", pnum);
 461
 462 out:
 463         mutex_unlock(&ubi->buf_mutex);
 464         if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err)) {
 465                 /*
 466                  * If a bit-flip or data integrity error was detected, the test
 467                  * has not passed because it happened on a freshly erased
 468                  * physical eraseblock which means something is wrong with it.
 469                  */
 470                 ubi_err("read problems on freshly erased PEB %d, must be bad",
 471                         pnum);
 472                 err = -EIO;
 473         }
 474         return err;
 475 }
 476
 477 /**
 478  * nor_erase_prepare - prepare a NOR flash PEB for erasure.
 479  * @ubi: UBI device description object
 480  * @pnum: physical eraseblock number to prepare
 481  *
 482  * NOR flash, or at least some of them, have peculiar embedded PEB erasure
 483  * algorithm: the PEB is first filled with zeroes, then it is erased. And
 484  * filling with zeroes starts from the end of the PEB. This was observed with
 485  * Spansion S29GL512N NOR flash.
 486  *
 487  * This means that in case of a power cut we may end up with intact data at the
 488  * beginning of the PEB, and all zeroes at the end of PEB. In other words, the
 489  * EC and VID headers are OK, but a large chunk of data at the end of PEB is
 490  * zeroed. This makes UBI mistakenly treat this PEB as used and associate it
 491  * with an LEB, which leads to subsequent failures (e.g., UBIFS fails).
 492  *
 493  * This function is called before erasing NOR PEBs and it zeroes out EC and VID
 494  * magic numbers in order to invalidate them and prevent the failures. Returns
 495  * zero in case of success and a negative error code in case of failure.
 496  */
 497 static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 498 {
 499         int err, err1;
 500         size_t written;
 501         loff_t addr;
 502         uint32_t data = 0;
 503         /*
 504          * Note, we cannot generally define VID header buffers on stack,
 505          * because of the way we deal with these buffers (see the header
 506          * comment in this file). But we know this is a NOR-specific piece of
 507          * code, so we can do this. But yes, this is error-prone and we should
 508          * (pre-)allocate VID header buffer instead.
 509          */
 510         struct ubi_vid_hdr vid_hdr;
 511
 512         /*
 513          * It is important to first invalidate the EC header, and then the VID
 514          * header. Otherwise a power cut may lead to valid EC header and
 515          * invalid VID header, in which case UBI will treat this PEB as
 516          * corrupted and will try to preserve it, and print scary warnings.
 517          */
 518         addr = (loff_t)pnum * ubi->peb_size;
 519         err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
 520         if (!err) {
 521                 addr += ubi->vid_hdr_aloffset;
 522                 err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
 523                 if (!err)
 524                         return 0;
 525         }
 526
 527         /*
 528          * We failed to write to the media. This was observed with Spansion
 529          * S29GL512N NOR flash. Most probably the previously eraseblock erasure
 530          * was interrupted at a very inappropriate moment, so it became
 531          * unwritable. In this case we probably anyway have garbage in this
 532          * PEB.
 533          */
 534         err1 = ubi_io_read_vid_hdr(ubi, pnum, &vid_hdr, 0);
 535         if (err1 == UBI_IO_BAD_HDR_EBADMSG || err1 == UBI_IO_BAD_HDR ||
 536             err1 == UBI_IO_FF) {
 537                 struct ubi_ec_hdr ec_hdr;
 538
 539                 err1 = ubi_io_read_ec_hdr(ubi, pnum, &ec_hdr, 0);
 540                 if (err1 == UBI_IO_BAD_HDR_EBADMSG || err1 == UBI_IO_BAD_HDR ||
 541                     err1 == UBI_IO_FF)
 542                         /*
 543                          * Both VID and EC headers are corrupted, so we can
 544                          * safely erase this PEB and not afraid that it will be
 545                          * treated as a valid PEB in case of an unclean reboot.
 546                          */
 547                         return 0;
 548         }
 549
 550         /*
 551          * The PEB contains a valid VID header, but we cannot invalidate it.
 552          * Supposedly the flash media or the driver is screwed up, so return an
 553          * error.
 554          */
 555         ubi_err("cannot invalidate PEB %d, write returned %d read returned %d",
 556                 pnum, err, err1);
 557         ubi_dump_flash(ubi, pnum, 0, ubi->peb_size);
 558         return -EIO;
 559 }
 560
 561 /**
 562  * ubi_io_sync_erase - synchronously erase a physical eraseblock.
 563  * @ubi: UBI device description object
 564  * @pnum: physical eraseblock number to erase
 565  * @torture: if this physical eraseblock has to be tortured
 566  *
 567  * This function synchronously erases physical eraseblock @pnum. If @torture
 568  * flag is not zero, the physical eraseblock is checked by means of writing
 569  * different patterns to it and reading them back. If the torturing is enabled,
 570  * the physical eraseblock is erased more than once.
 571  *
 572  * This function returns the number of erasures made in case of success, %-EIO
 573  * if the erasure failed or the torturing test failed, and other negative error
 574  * codes in case of other errors. Note, %-EIO means that the physical
 575  * eraseblock is bad.
 576  */
 577 int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
 578 {
 579         int err, ret = 0;
 580
 581         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 582
 583         err = self_check_not_bad(ubi, pnum);
 584         if (err != 0)
 585                 return err;
 586
 587         if (ubi->ro_mode) {
 588                 ubi_err("read-only mode");
 589                 return -EROFS;
 590         }
 591
 592         if (ubi->nor_flash) {
 593                 err = nor_erase_prepare(ubi, pnum);
 594                 if (err)
 595                         return err;
 596         }
 597
 598         if (torture) {
 599                 ret = torture_peb(ubi, pnum);
 600                 if (ret < 0)
 601                         return ret;
 602         }
 603
 604         err = do_sync_erase(ubi, pnum);
 605         if (err)
 606                 return err;
 607
 608         return ret + 1;
 609 }
 610
 611 /**
 612  * ubi_io_is_bad - check if a physical eraseblock is bad.
 613  * @ubi: UBI device description object
 614  * @pnum: the physical eraseblock number to check
 615  *
 616  * This function returns a positive number if the physical eraseblock is bad,
 617  * zero if not, and a negative error code if an error occurred.
 618  */
 619 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum)
 620 {
 621         struct mtd_info *mtd = ubi->mtd;
 622
 623         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 624
 625         if (ubi->bad_allowed) {
 626                 int ret;
 627
 628                 ret = mtd_block_isbad(mtd, (loff_t)pnum * ubi->peb_size);
 629                 if (ret < 0)
 630                         ubi_err("error %d while checking if PEB %d is bad",
 631                                 ret, pnum);
 632                 else if (ret)
 633                         dbg_io("PEB %d is bad", pnum);
 634                 return ret;
 635         }
 636
 637         return 0;
 638 }
 639
 640 /**
 641  * ubi_io_mark_bad - mark a physical eraseblock as bad.
 642  * @ubi: UBI device description object
 643  * @pnum: the physical eraseblock number to mark
 644  *
 645  * This function returns zero in case of success and a negative error code in
 646  * case of failure.
 647  */
 648 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
 649 {
 650         int err;
 651         struct mtd_info *mtd = ubi->mtd;
 652
 653         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 654
 655         if (ubi->ro_mode) {
 656                 ubi_err("read-only mode");
 657                 return -EROFS;
 658         }
 659
 660         if (!ubi->bad_allowed)
 661                 return 0;
 662
 663         err = mtd_block_markbad(mtd, (loff_t)pnum * ubi->peb_size);
 664         if (err)
 665                 ubi_err("cannot mark PEB %d bad, error %d", pnum, err);
 666         return err;
 667 }
 668
 669 /**
 670  * validate_ec_hdr - validate an erase counter header.
 671  * @ubi: UBI device description object
 672  * @ec_hdr: the erase counter header to check
 673  *
 674  * This function returns zero if the erase counter header is OK, and %1 if
 675  * not.
 676  */
 677 static int validate_ec_hdr(const struct ubi_device *ubi,
 678                            const struct ubi_ec_hdr *ec_hdr)
 679 {
 680         long long ec;
 681         int vid_hdr_offset, leb_start;
 682
 683         ec = be64_to_cpu(ec_hdr->ec);
 684         vid_hdr_offset = be32_to_cpu(ec_hdr->vid_hdr_offset);
 685         leb_start = be32_to_cpu(ec_hdr->data_offset);
 686
 687         if (ec_hdr->version != UBI_VERSION) {
 688                 ubi_err("node with incompatible UBI version found: "
 689                         "this UBI version is %d, image version is %d",
 690                         UBI_VERSION, (int)ec_hdr->version);
 691                 goto bad;
 692         }
 693
 694         if (vid_hdr_offset != ubi->vid_hdr_offset) {
 695                 ubi_err("bad VID header offset %d, expected %d",
 696                         vid_hdr_offset, ubi->vid_hdr_offset);
 697                 goto bad;
 698         }
 699
 700         if (leb_start != ubi->leb_start) {
 701                 ubi_err("bad data offset %d, expected %d",
 702                         leb_start, ubi->leb_start);
 703                 goto bad;
 704         }
 705
 706         if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
 707                 ubi_err("bad erase counter %lld", ec);
 708                 goto bad;
 709         }
 710
 711         return 0;
 712
 713 bad:
 714         ubi_err("bad EC header");
 715         ubi_dump_ec_hdr(ec_hdr);
 716         dump_stack();
 717         return 1;
 718 }
 719
 720 /**
 721  * ubi_io_read_ec_hdr - read and check an erase counter header.
 722  * @ubi: UBI device description object
 723  * @pnum: physical eraseblock to read from
 724  * @ec_hdr: a &struct ubi_ec_hdr object where to store the read erase counter
 725  * header
 726  * @verbose: be verbose if the header is corrupted or was not found
 727  *
 728  * This function reads erase counter header from physical eraseblock @pnum and
 729  * stores it in @ec_hdr. This function also checks CRC checksum of the read
 730  * erase counter header. The following codes may be returned:
 731  *
 732  * o %0 if the CRC checksum is correct and the header was successfully read;
 733  * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 734  *   and corrected by the flash driver; this is harmless but may indicate that
 735  *   this eraseblock may become bad soon (but may be not);
 736  * o %UBI_IO_BAD_HDR if the erase counter header is corrupted (a CRC error);
 737  * o %UBI_IO_BAD_HDR_EBADMSG is the same as %UBI_IO_BAD_HDR, but there also was
 738  *   a data integrity error (uncorrectable ECC error in case of NAND);
 739  * o %UBI_IO_FF if only 0xFF bytes were read (the PEB is supposedly empty)
 740  * o a negative error code in case of failure.
 741  */
 742 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 743                        struct ubi_ec_hdr *ec_hdr, int verbose)
 744 {
 745         int err, read_err;
 746         uint32_t crc, magic, hdr_crc;
 747
 748         dbg_io("read EC header from PEB %d", pnum);
 749         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 750
 751         read_err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
 752         if (read_err) {
 753                 if (read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
 754                         return read_err;
 755
 756                 /*
 757                  * We read all the data, but either a correctable bit-flip
 758                  * occurred, or MTD reported a data integrity error
 759                  * (uncorrectable ECC error in case of NAND). The former is
 760                  * harmless, the later may mean that the read data is
 761                  * corrupted. But we have a CRC check-sum and we will detect
 762                  * this. If the EC header is still OK, we just report this as
 763                  * there was a bit-flip, to force scrubbing.
 764                  */
 765         }
 766
 767         magic = be32_to_cpu(ec_hdr->magic);
 768         if (magic != UBI_EC_HDR_MAGIC) {
 769                 if (mtd_is_eccerr(read_err))
 770                         return UBI_IO_BAD_HDR_EBADMSG;
 771
 772                 /*
 773                  * The magic field is wrong. Let's check if we have read all
 774                  * 0xFF. If yes, this physical eraseblock is assumed to be
 775                  * empty.
 776                  */
 777                 if (ubi_check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
 778                         /* The physical eraseblock is supposedly empty */
 779                         if (verbose)
 780                                 ubi_warn("no EC header found at PEB %d, "
 781                                          "only 0xFF bytes", pnum);
 782                         dbg_bld("no EC header found at PEB %d, "
 783                                 "only 0xFF bytes", pnum);
 784                         if (!read_err)
 785                                 return UBI_IO_FF;
 786                         else
 787                                 return UBI_IO_FF_BITFLIPS;
 788                 }
 789
 790                 /*
 791                  * This is not a valid erase counter header, and these are not
 792                  * 0xFF bytes. Report that the header is corrupted.
 793                  */
 794                 if (verbose) {
 795                         ubi_warn("bad magic number at PEB %d: %08x instead of "
 796                                  "%08x", pnum, magic, UBI_EC_HDR_MAGIC);
 797                         ubi_dump_ec_hdr(ec_hdr);
 798                 }
 799                 dbg_bld("bad magic number at PEB %d: %08x instead of "
 800                         "%08x", pnum, magic, UBI_EC_HDR_MAGIC);
 801                 return UBI_IO_BAD_HDR;
 802         }
 803
 804         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 805         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
 806
 807         if (hdr_crc != crc) {
 808                 if (verbose) {
 809                         ubi_warn("bad EC header CRC at PEB %d, calculated "
 810                                  "%#08x, read %#08x", pnum, crc, hdr_crc);
 811                         ubi_dump_ec_hdr(ec_hdr);
 812                 }
 813                 dbg_bld("bad EC header CRC at PEB %d, calculated "
 814                         "%#08x, read %#08x", pnum, crc, hdr_crc);
 815
 816                 if (!read_err)
 817                         return UBI_IO_BAD_HDR;
 818                 else
 819                         return UBI_IO_BAD_HDR_EBADMSG;
 820         }
 821
 822         /* And of course validate what has just been read from the media */
 823         err = validate_ec_hdr(ubi, ec_hdr);
 824         if (err) {
 825                 ubi_err("validation failed for PEB %d", pnum);
 826                 return -EINVAL;
 827         }
 828
 829         /*
 830          * If there was %-EBADMSG, but the header CRC is still OK, report about
 831          * a bit-flip to force scrubbing on this PEB.
 832          */
 833         return read_err ? UBI_IO_BITFLIPS : 0;
 834 }
 835
 836 /**
 837  * ubi_io_write_ec_hdr - write an erase counter header.
 838  * @ubi: UBI device description object
 839  * @pnum: physical eraseblock to write to
 840  * @ec_hdr: the erase counter header to write
 841  *
 842  * This function writes erase counter header described by @ec_hdr to physical
 843  * eraseblock @pnum. It also fills most fields of @ec_hdr before writing, so
 844  * the caller do not have to fill them. Callers must only fill the @ec_hdr->ec
 845  * field.
 846  *
 847  * This function returns zero in case of success and a negative error code in
 848  * case of failure. If %-EIO is returned, the physical eraseblock most probably
 849  * went bad.
 850  */
 851 int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 852                         struct ubi_ec_hdr *ec_hdr)
 853 {
 854         int err;
 855         uint32_t crc;
 856
 857         dbg_io("write EC header to PEB %d", pnum);
 858         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 859
 860         ec_hdr->magic = cpu_to_be32(UBI_EC_HDR_MAGIC);
 861         ec_hdr->version = UBI_VERSION;
 862         ec_hdr->vid_hdr_offset = cpu_to_be32(ubi->vid_hdr_offset);
 863         ec_hdr->data_offset = cpu_to_be32(ubi->leb_start);
 864         ec_hdr->image_seq = cpu_to_be32(ubi->image_seq);
 865         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 866         ec_hdr->hdr_crc = cpu_to_be32(crc);
 867
 868         err = self_check_ec_hdr(ubi, pnum, ec_hdr);
 869         if (err)
 870                 return err;
 871
 872         err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
 873         return err;
 874 }
 875
 876 /**
 877  * validate_vid_hdr - validate a volume identifier header.
 878  * @ubi: UBI device description object
 879  * @vid_hdr: the volume identifier header to check
 880  *
 881  * This function checks that data stored in the volume identifier header
 882  * @vid_hdr. Returns zero if the VID header is OK and %1 if not.
 883  */
 884 static int validate_vid_hdr(const struct ubi_device *ubi,
 885                             const struct ubi_vid_hdr *vid_hdr)
 886 {
 887         int vol_type = vid_hdr->vol_type;
 888         int copy_flag = vid_hdr->copy_flag;
 889         int vol_id = be32_to_cpu(vid_hdr->vol_id);
 890         int lnum = be32_to_cpu(vid_hdr->lnum);
 891         int compat = vid_hdr->compat;
 892         int data_size = be32_to_cpu(vid_hdr->data_size);
 893         int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
 894         int data_pad = be32_to_cpu(vid_hdr->data_pad);
 895         int data_crc = be32_to_cpu(vid_hdr->data_crc);
 896         int usable_leb_size = ubi->leb_size - data_pad;
 897
 898         if (copy_flag != 0 && copy_flag != 1) {
 899                 ubi_err("bad copy_flag");
 900                 goto bad;
 901         }
 902
 903         if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
 904             data_pad < 0) {
 905                 ubi_err("negative values");
 906                 goto bad;
 907         }
 908
 909         if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
 910                 ubi_err("bad vol_id");
 911                 goto bad;
 912         }
 913
 914         if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
 915                 ubi_err("bad compat");
 916                 goto bad;
 917         }
 918
 919         if (vol_id >= UBI_INTERNAL_VOL_START && compat != UBI_COMPAT_DELETE &&
 920             compat != UBI_COMPAT_RO && compat != UBI_COMPAT_PRESERVE &&
 921             compat != UBI_COMPAT_REJECT) {
 922                 ubi_err("bad compat");
 923                 goto bad;
 924         }
 925
 926         if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
 927                 ubi_err("bad vol_type");
 928                 goto bad;
 929         }
 930
 931         if (data_pad >= ubi->leb_size / 2) {
 932                 ubi_err("bad data_pad");
 933                 goto bad;
 934         }
 935
 936         if (vol_type == UBI_VID_STATIC) {
 937                 /*
 938                  * Although from high-level point of view static volumes may
 939                  * contain zero bytes of data, but no VID headers can contain
 940                  * zero at these fields, because they empty volumes do not have
 941                  * mapped logical eraseblocks.
 942                  */
 943                 if (used_ebs == 0) {
 944                         ubi_err("zero used_ebs");
 945                         goto bad;
 946                 }
 947                 if (data_size == 0) {
 948                         ubi_err("zero data_size");
 949                         goto bad;
 950                 }
 951                 if (lnum < used_ebs - 1) {
 952                         if (data_size != usable_leb_size) {
 953                                 ubi_err("bad data_size");
 954                                 goto bad;
 955                         }
 956                 } else if (lnum == used_ebs - 1) {
 957                         if (data_size == 0) {
 958                                 ubi_err("bad data_size at last LEB");
 959                                 goto bad;
 960                         }
 961                 } else {
 962                         ubi_err("too high lnum");
 963                         goto bad;
 964                 }
 965         } else {
 966                 if (copy_flag == 0) {
 967                         if (data_crc != 0) {
 968                                 ubi_err("non-zero data CRC");
 969                                 goto bad;
 970                         }
 971                         if (data_size != 0) {
 972                                 ubi_err("non-zero data_size");
 973                                 goto bad;
 974                         }
 975                 } else {
 976                         if (data_size == 0) {
 977                                 ubi_err("zero data_size of copy");
 978                                 goto bad;
 979                         }
 980                 }
 981                 if (used_ebs != 0) {
 982                         ubi_err("bad used_ebs");
 983                         goto bad;
 984                 }
 985         }
 986
 987         return 0;
 988
 989 bad:
 990         ubi_err("bad VID header");
 991         ubi_dump_vid_hdr(vid_hdr);
 992         dump_stack();
 993         return 1;
 994 }
 995
 996 /**
 997  * ubi_io_read_vid_hdr - read and check a volume identifier header.
 998  * @ubi: UBI device description object
 999  * @pnum: physical eraseblock number to read from
1000  * @vid_hdr: &struct ubi_vid_hdr object where to store the read volume
1001  * identifier header
1002  * @verbose: be verbose if the header is corrupted or wasn't found
1003  *
1004  * This function reads the volume identifier header from physical eraseblock
1005  * @pnum and stores it in @vid_hdr. It also checks CRC checksum of the read
1006  * volume identifier header. The error codes are the same as in
1007  * 'ubi_io_read_ec_hdr()'.
1008  *
1009  * Note, the implementation of this function is also very similar to
1010  * 'ubi_io_read_ec_hdr()', so refer commentaries in 'ubi_io_read_ec_hdr()'.
1011  */
1012 int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
1013                         struct ubi_vid_hdr *vid_hdr, int verbose)
1014 {
1015         int err, read_err;
1016         uint32_t crc, magic, hdr_crc;
1017         void *p;
1018
1019         dbg_io("read VID header from PEB %d", pnum);
1020         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
1021
1022         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1023         read_err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1024                           ubi->vid_hdr_alsize);
1025         if (read_err && read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
1026                 return read_err;
1027
1028         magic = be32_to_cpu(vid_hdr->magic);
1029         if (magic != UBI_VID_HDR_MAGIC) {
1030                 if (mtd_is_eccerr(read_err))
1031                         return UBI_IO_BAD_HDR_EBADMSG;
1032
1033                 if (ubi_check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
1034                         if (verbose)
1035                                 ubi_warn("no VID header found at PEB %d, "
1036                                          "only 0xFF bytes", pnum);
1037                         dbg_bld("no VID header found at PEB %d, "
1038                                 "only 0xFF bytes", pnum);
1039                         if (!read_err)
1040                                 return UBI_IO_FF;
1041                         else
1042                                 return UBI_IO_FF_BITFLIPS;
1043                 }
1044
1045                 if (verbose) {
1046                         ubi_warn("bad magic number at PEB %d: %08x instead of "
1047                                  "%08x", pnum, magic, UBI_VID_HDR_MAGIC);
1048                         ubi_dump_vid_hdr(vid_hdr);
1049                 }
1050                 dbg_bld("bad magic number at PEB %d: %08x instead of "
1051                         "%08x", pnum, magic, UBI_VID_HDR_MAGIC);
1052                 return UBI_IO_BAD_HDR;
1053         }
1054
1055         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1056         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1057
1058         if (hdr_crc != crc) {
1059                 if (verbose) {
1060                         ubi_warn("bad CRC at PEB %d, calculated %#08x, "
1061                                  "read %#08x", pnum, crc, hdr_crc);
1062                         ubi_dump_vid_hdr(vid_hdr);
1063                 }
1064                 dbg_bld("bad CRC at PEB %d, calculated %#08x, "
1065                         "read %#08x", pnum, crc, hdr_crc);
1066                 if (!read_err)
1067                         return UBI_IO_BAD_HDR;
1068                 else
1069                         return UBI_IO_BAD_HDR_EBADMSG;
1070         }
1071
1072         err = validate_vid_hdr(ubi, vid_hdr);
1073         if (err) {
1074                 ubi_err("validation failed for PEB %d", pnum);
1075                 return -EINVAL;
1076         }
1077
1078         return read_err ? UBI_IO_BITFLIPS : 0;
1079 }
1080
1081 /**
1082  * ubi_io_write_vid_hdr - write a volume identifier header.
1083  * @ubi: UBI device description object
1084  * @pnum: the physical eraseblock number to write to
1085  * @vid_hdr: the volume identifier header to write
1086  *
1087  * This function writes the volume identifier header described by @vid_hdr to
1088  * physical eraseblock @pnum. This function automatically fills the
1089  * @vid_hdr->magic and the @vid_hdr->version fields, as well as calculates
1090  * header CRC checksum and stores it at vid_hdr->hdr_crc.
1091  *
1092  * This function returns zero in case of success and a negative error code in
1093  * case of failure. If %-EIO is returned, the physical eraseblock probably went
1094  * bad.
1095  */
1096 int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
1097                          struct ubi_vid_hdr *vid_hdr)
1098 {
1099         int err;
1100         uint32_t crc;
1101         void *p;
1102
1103         dbg_io("write VID header to PEB %d", pnum);
1104         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
1105
1106         err = self_check_peb_ec_hdr(ubi, pnum);
1107         if (err)
1108                 return err;
1109
1110         vid_hdr->magic = cpu_to_be32(UBI_VID_HDR_MAGIC);
1111         vid_hdr->version = UBI_VERSION;
1112         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1113         vid_hdr->hdr_crc = cpu_to_be32(crc);
1114
1115         err = self_check_vid_hdr(ubi, pnum, vid_hdr);
1116         if (err)
1117                 return err;
1118
1119         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1120         err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
1121                            ubi->vid_hdr_alsize);
1122         return err;
1123 }
1124
1125 /**
1126  * self_check_not_bad - ensure that a physical eraseblock is not bad.
1127  * @ubi: UBI device description object
1128  * @pnum: physical eraseblock number to check
1129  *
1130  * This function returns zero if the physical eraseblock is good, %-EINVAL if
1131  * it is bad and a negative error code if an error occurred.
1132  */
1133 static int self_check_not_bad(const struct ubi_device *ubi, int pnum)
1134 {
1135         int err;
1136
1137         if (!ubi->dbg->chk_io)
1138                 return 0;
1139
1140         err = ubi_io_is_bad(ubi, pnum);
1141         if (!err)
1142                 return err;
1143
1144         ubi_err("self-check failed for PEB %d", pnum);
1145         dump_stack();
1146         return err > 0 ? -EINVAL : err;
1147 }
1148
1149 /**
1150  * self_check_ec_hdr - check if an erase counter header is all right.
1151  * @ubi: UBI device description object
1152  * @pnum: physical eraseblock number the erase counter header belongs to
1153  * @ec_hdr: the erase counter header to check
1154  *
1155  * This function returns zero if the erase counter header contains valid
1156  * values, and %-EINVAL if not.
1157  */
1158 static int self_check_ec_hdr(const struct ubi_device *ubi, int pnum,
1159                              const struct ubi_ec_hdr *ec_hdr)
1160 {
1161         int err;
1162         uint32_t magic;
1163
1164         if (!ubi->dbg->chk_io)
1165                 return 0;
1166
1167         magic = be32_to_cpu(ec_hdr->magic);
1168         if (magic != UBI_EC_HDR_MAGIC) {
1169                 ubi_err("bad magic %#08x, must be %#08x",
1170                         magic, UBI_EC_HDR_MAGIC);
1171                 goto fail;
1172         }
1173
1174         err = validate_ec_hdr(ubi, ec_hdr);
1175         if (err) {
1176                 ubi_err("self-check failed for PEB %d", pnum);
1177                 goto fail;
1178         }
1179
1180         return 0;
1181
1182 fail:
1183         ubi_dump_ec_hdr(ec_hdr);
1184         dump_stack();
1185         return -EINVAL;
1186 }
1187
1188 /**
1189  * self_check_peb_ec_hdr - check erase counter header.
1190  * @ubi: UBI device description object
1191  * @pnum: the physical eraseblock number to check
1192  *
1193  * This function returns zero if the erase counter header is all right and and
1194  * a negative error code if not or if an error occurred.
1195  */
1196 static int self_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
1197 {
1198         int err;
1199         uint32_t crc, hdr_crc;
1200         struct ubi_ec_hdr *ec_hdr;
1201
1202         if (!ubi->dbg->chk_io)
1203                 return 0;
1204
1205         ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
1206         if (!ec_hdr)
1207                 return -ENOMEM;
1208
1209         err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
1210         if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
1211                 goto exit;
1212
1213         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
1214         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
1215         if (hdr_crc != crc) {
1216                 ubi_err("bad CRC, calculated %#08x, read %#08x", crc, hdr_crc);
1217                 ubi_err("self-check failed for PEB %d", pnum);
1218                 ubi_dump_ec_hdr(ec_hdr);
1219                 dump_stack();
1220                 err = -EINVAL;
1221                 goto exit;
1222         }
1223
1224         err = self_check_ec_hdr(ubi, pnum, ec_hdr);
1225
1226 exit:
1227         kfree(ec_hdr);
1228         return err;
1229 }
1230
1231 /**
1232  * self_check_vid_hdr - check that a volume identifier header is all right.
1233  * @ubi: UBI device description object
1234  * @pnum: physical eraseblock number the volume identifier header belongs to
1235  * @vid_hdr: the volume identifier header to check
1236  *
1237  * This function returns zero if the volume identifier header is all right, and
1238  * %-EINVAL if not.
1239  */
1240 static int self_check_vid_hdr(const struct ubi_device *ubi, int pnum,
1241                               const struct ubi_vid_hdr *vid_hdr)
1242 {
1243         int err;
1244         uint32_t magic;
1245
1246         if (!ubi->dbg->chk_io)
1247                 return 0;
1248
1249         magic = be32_to_cpu(vid_hdr->magic);
1250         if (magic != UBI_VID_HDR_MAGIC) {
1251                 ubi_err("bad VID header magic %#08x at PEB %d, must be %#08x",
1252                         magic, pnum, UBI_VID_HDR_MAGIC);
1253                 goto fail;
1254         }
1255
1256         err = validate_vid_hdr(ubi, vid_hdr);
1257         if (err) {
1258                 ubi_err("self-check failed for PEB %d", pnum);
1259                 goto fail;
1260         }
1261
1262         return err;
1263
1264 fail:
1265         ubi_err("self-check failed for PEB %d", pnum);
1266         ubi_dump_vid_hdr(vid_hdr);
1267         dump_stack();
1268         return -EINVAL;
1269
1270 }
1271
1272 /**
1273  * self_check_peb_vid_hdr - check volume identifier header.
1274  * @ubi: UBI device description object
1275  * @pnum: the physical eraseblock number to check
1276  *
1277  * This function returns zero if the volume identifier header is all right,
1278  * and a negative error code if not or if an error occurred.
1279  */
1280 static int self_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
1281 {
1282         int err;
1283         uint32_t crc, hdr_crc;
1284         struct ubi_vid_hdr *vid_hdr;
1285         void *p;
1286
1287         if (!ubi->dbg->chk_io)
1288                 return 0;
1289
1290         vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
1291         if (!vid_hdr)
1292                 return -ENOMEM;
1293
1294         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1295         err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1296                           ubi->vid_hdr_alsize);
1297         if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
1298                 goto exit;
1299
1300         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_EC_HDR_SIZE_CRC);
1301         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1302         if (hdr_crc != crc) {
1303                 ubi_err("bad VID header CRC at PEB %d, calculated %#08x, "
1304                         "read %#08x", pnum, crc, hdr_crc);
1305                 ubi_err("self-check failed for PEB %d", pnum);
1306                 ubi_dump_vid_hdr(vid_hdr);
1307                 dump_stack();
1308                 err = -EINVAL;
1309                 goto exit;
1310         }
1311
1312         err = self_check_vid_hdr(ubi, pnum, vid_hdr);
1313
1314 exit:
1315         ubi_free_vid_hdr(ubi, vid_hdr);
1316         return err;
1317 }
1318
1319 /**
1320  * self_check_write - make sure write succeeded.
1321  * @ubi: UBI device description object
1322  * @buf: buffer with data which were written
1323  * @pnum: physical eraseblock number the data were written to
1324  * @offset: offset within the physical eraseblock the data were written to
1325  * @len: how many bytes were written
1326  *
1327  * This functions reads data which were recently written and compares it with
1328  * the original data buffer - the data have to match. Returns zero if the data
1329  * match and a negative error code if not or in case of failure.
1330  */
1331 static int self_check_write(struct ubi_device *ubi, const void *buf, int pnum,
1332                             int offset, int len)
1333 {
1334         int err, i;
1335         size_t read;
1336         void *buf1;
1337         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1338
1339         if (!ubi->dbg->chk_io)
1340                 return 0;
1341
1342         buf1 = __vmalloc(len, GFP_NOFS, PAGE_KERNEL);
1343         if (!buf1) {
1344                 ubi_err("cannot allocate memory to check writes");
1345                 return 0;
1346         }
1347
1348         err = mtd_read(ubi->mtd, addr, len, &read, buf1);
1349         if (err && !mtd_is_bitflip(err))
1350                 goto out_free;
1351
1352         for (i = 0; i < len; i++) {
1353                 uint8_t c = ((uint8_t *)buf)[i];
1354                 uint8_t c1 = ((uint8_t *)buf1)[i];
1355                 int dump_len;
1356
1357                 if (c == c1)
1358                         continue;
1359
1360                 ubi_err("self-check failed for PEB %d:%d, len %d",
1361                         pnum, offset, len);
1362                 ubi_msg("data differ at position %d", i);
1363                 dump_len = max_t(int, 128, len - i);
1364                 ubi_msg("hex dump of the original buffer from %d to %d",
1365                         i, i + dump_len);
1366                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1367                                buf + i, dump_len, 1);
1368                 ubi_msg("hex dump of the read buffer from %d to %d",
1369                         i, i + dump_len);
1370                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1371                                buf1 + i, dump_len, 1);
1372                 dump_stack();
1373                 err = -EINVAL;
1374                 goto out_free;
1375         }
1376
1377         vfree(buf1);
1378         return 0;
1379
1380 out_free:
1381         vfree(buf1);
1382         return err;
1383 }
1384
1385 /**
1386  * ubi_self_check_all_ff - check that a region of flash is empty.
1387  * @ubi: UBI device description object
1388  * @pnum: the physical eraseblock number to check
1389  * @offset: the starting offset within the physical eraseblock to check
1390  * @len: the length of the region to check
1391  *
1392  * This function returns zero if only 0xFF bytes are present at offset
1393  * @offset of the physical eraseblock @pnum, and a negative error code if not
1394  * or if an error occurred.
1395  */
1396 int ubi_self_check_all_ff(struct ubi_device *ubi, int pnum, int offset, int len)
1397 {
1398         size_t read;
1399         int err;
1400         void *buf;
1401         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1402
1403         if (!ubi->dbg->chk_io)
1404                 return 0;
1405
1406         buf = __vmalloc(len, GFP_NOFS, PAGE_KERNEL);
1407         if (!buf) {
1408                 ubi_err("cannot allocate memory to check for 0xFFs");
1409                 return 0;
1410         }
1411
1412         err = mtd_read(ubi->mtd, addr, len, &read, buf);
1413         if (err && !mtd_is_bitflip(err)) {
1414                 ubi_err("error %d while reading %d bytes from PEB %d:%d, "
1415                         "read %zd bytes", err, len, pnum, offset, read);
1416                 goto error;
1417         }
1418
1419         err = ubi_check_pattern(buf, 0xFF, len);
1420         if (err == 0) {
1421                 ubi_err("flash region at PEB %d:%d, length %d does not "
1422                         "contain all 0xFF bytes", pnum, offset, len);
1423                 goto fail;
1424         }
1425
1426         vfree(buf);
1427         return 0;
1428
1429 fail:
1430         ubi_err("self-check failed for PEB %d", pnum);
1431         ubi_msg("hex dump of the %d-%d region", offset, offset + len);
1432         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, buf, len, 1);
1433         err = -EINVAL;
1434 error:
1435         dump_stack();
1436         vfree(buf);
1437         return err;
1438 }