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                         ubi_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 %d:%d, read only %zd bytes, retry",
 187                                  err, errstr, len, pnum, offset, read);
 188                         yield();
 189                         goto retry;
 190                 }
 191
 192                 ubi_err("error %d%s while reading %d bytes from PEB %d:%d, read %zd bytes",
 193                         err, errstr, len, pnum, offset, read);
 194                 dump_stack();
 195
 196                 /*
 197                  * The driver should never return -EBADMSG if it failed to read
 198                  * all the requested data. But some buggy drivers might do
 199                  * this, so we change it to -EIO.
 200                  */
 201                 if (read != len && mtd_is_eccerr(err)) {
 202                         ubi_assert(0);
 203                         err = -EIO;
 204                 }
 205         } else {
 206                 ubi_assert(len == read);
 207
 208                 if (ubi_dbg_is_bitflip(ubi)) {
 209                         dbg_gen("bit-flip (emulated)");
 210                         err = UBI_IO_BITFLIPS;
 211                 }
 212         }
 213
 214         return err;
 215 }
 216
 217 /**
 218  * ubi_io_write - write data to a physical eraseblock.
 219  * @ubi: UBI device description object
 220  * @buf: buffer with the data to write
 221  * @pnum: physical eraseblock number to write to
 222  * @offset: offset within the physical eraseblock where to write
 223  * @len: how many bytes to write
 224  *
 225  * This function writes @len bytes of data from buffer @buf to offset @offset
 226  * of physical eraseblock @pnum. If all the data were successfully written,
 227  * zero is returned. If an error occurred, this function returns a negative
 228  * error code. If %-EIO is returned, the physical eraseblock most probably went
 229  * bad.
 230  *
 231  * Note, in case of an error, it is possible that something was still written
 232  * to the flash media, but may be some garbage.
 233  */
 234 int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
 235                  int len)
 236 {
 237         int err;
 238         size_t written;
 239         loff_t addr;
 240
 241         dbg_io("write %d bytes to PEB %d:%d", len, pnum, offset);
 242
 243         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 244         ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 245         ubi_assert(offset % ubi->hdrs_min_io_size == 0);
 246         ubi_assert(len > 0 && len % ubi->hdrs_min_io_size == 0);
 247
 248         if (ubi->ro_mode) {
 249                 ubi_err("read-only mode");
 250                 return -EROFS;
 251         }
 252
 253         err = self_check_not_bad(ubi, pnum);
 254         if (err)
 255                 return err;
 256
 257         /* The area we are writing to has to contain all 0xFF bytes */
 258         err = ubi_self_check_all_ff(ubi, pnum, offset, len);
 259         if (err)
 260                 return err;
 261
 262         if (offset >= ubi->leb_start) {
 263                 /*
 264                  * We write to the data area of the physical eraseblock. Make
 265                  * sure it has valid EC and VID headers.
 266                  */
 267                 err = self_check_peb_ec_hdr(ubi, pnum);
 268                 if (err)
 269                         return err;
 270                 err = self_check_peb_vid_hdr(ubi, pnum);
 271                 if (err)
 272                         return err;
 273         }
 274
 275         if (ubi_dbg_is_write_failure(ubi)) {
 276                 ubi_err("cannot write %d bytes to PEB %d:%d (emulated)",
 277                         len, pnum, offset);
 278                 dump_stack();
 279                 return -EIO;
 280         }
 281
 282         addr = (loff_t)pnum * ubi->peb_size + offset;
 283         err = mtd_write(ubi->mtd, addr, len, &written, buf);
 284         if (err) {
 285                 ubi_err("error %d while writing %d bytes to PEB %d:%d, written %zd bytes",
 286                         err, len, pnum, offset, written);
 287                 dump_stack();
 288                 ubi_dump_flash(ubi, pnum, offset, len);
 289         } else
 290                 ubi_assert(written == len);
 291
 292         if (!err) {
 293                 err = self_check_write(ubi, buf, pnum, offset, len);
 294                 if (err)
 295                         return err;
 296
 297                 /*
 298                  * Since we always write sequentially, the rest of the PEB has
 299                  * to contain only 0xFF bytes.
 300                  */
 301                 offset += len;
 302                 len = ubi->peb_size - offset;
 303                 if (len)
 304                         err = ubi_self_check_all_ff(ubi, pnum, offset, len);
 305         }
 306
 307         return err;
 308 }
 309
 310 /**
 311  * erase_callback - MTD erasure call-back.
 312  * @ei: MTD erase information object.
 313  *
 314  * Note, even though MTD erase interface is asynchronous, all the current
 315  * implementations are synchronous anyway.
 316  */
 317 static void erase_callback(struct erase_info *ei)
 318 {
 319         wake_up_interruptible((wait_queue_head_t *)ei->priv);
 320 }
 321
 322 /**
 323  * do_sync_erase - synchronously erase a physical eraseblock.
 324  * @ubi: UBI device description object
 325  * @pnum: the physical eraseblock number to erase
 326  *
 327  * This function synchronously erases physical eraseblock @pnum and returns
 328  * zero in case of success and a negative error code in case of failure. If
 329  * %-EIO is returned, the physical eraseblock most probably went bad.
 330  */
 331 static int do_sync_erase(struct ubi_device *ubi, int pnum)
 332 {
 333         int err, retries = 0;
 334         struct erase_info ei;
 335         wait_queue_head_t wq;
 336
 337         dbg_io("erase PEB %d", pnum);
 338         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 339
 340         if (ubi->ro_mode) {
 341                 ubi_err("read-only mode");
 342                 return -EROFS;
 343         }
 344
 345 retry:
 346         init_waitqueue_head(&wq);
 347         memset(&ei, 0, sizeof(struct erase_info));
 348
 349         ei.mtd      = ubi->mtd;
 350         ei.addr     = (loff_t)pnum * ubi->peb_size;
 351         ei.len      = ubi->peb_size;
 352         ei.callback = erase_callback;
 353         ei.priv     = (unsigned long)&wq;
 354
 355         err = mtd_erase(ubi->mtd, &ei);
 356         if (err) {
 357                 if (retries++ < UBI_IO_RETRIES) {
 358                         ubi_warn("error %d while erasing PEB %d, retry",
 359                                  err, pnum);
 360                         yield();
 361                         goto retry;
 362                 }
 363                 ubi_err("cannot erase PEB %d, error %d", pnum, err);
 364                 dump_stack();
 365                 return err;
 366         }
 367
 368         err = wait_event_interruptible(wq, ei.state == MTD_ERASE_DONE ||
 369                                            ei.state == MTD_ERASE_FAILED);
 370         if (err) {
 371                 ubi_err("interrupted PEB %d erasure", pnum);
 372                 return -EINTR;
 373         }
 374
 375         if (ei.state == MTD_ERASE_FAILED) {
 376                 if (retries++ < UBI_IO_RETRIES) {
 377                         ubi_warn("error while erasing PEB %d, retry", pnum);
 378                         yield();
 379                         goto retry;
 380                 }
 381                 ubi_err("cannot erase PEB %d", pnum);
 382                 dump_stack();
 383                 return -EIO;
 384         }
 385
 386         err = ubi_self_check_all_ff(ubi, pnum, 0, ubi->peb_size);
 387         if (err)
 388                 return err;
 389
 390         if (ubi_dbg_is_erase_failure(ubi)) {
 391                 ubi_err("cannot erase PEB %d (emulated)", pnum);
 392                 return -EIO;
 393         }
 394
 395         return 0;
 396 }
 397
 398 /* Patterns to write to a physical eraseblock when torturing it */
 399 static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
 400
 401 /**
 402  * torture_peb - test a supposedly bad physical eraseblock.
 403  * @ubi: UBI device description object
 404  * @pnum: the physical eraseblock number to test
 405  *
 406  * This function returns %-EIO if the physical eraseblock did not pass the
 407  * test, a positive number of erase operations done if the test was
 408  * successfully passed, and other negative error codes in case of other errors.
 409  */
 410 static int torture_peb(struct ubi_device *ubi, int pnum)
 411 {
 412         int err, i, patt_count;
 413
 414         ubi_msg("run torture test for PEB %d", pnum);
 415         patt_count = ARRAY_SIZE(patterns);
 416         ubi_assert(patt_count > 0);
 417
 418         mutex_lock(&ubi->buf_mutex);
 419         for (i = 0; i < patt_count; i++) {
 420                 err = do_sync_erase(ubi, pnum);
 421                 if (err)
 422                         goto out;
 423
 424                 /* Make sure the PEB contains only 0xFF bytes */
 425                 err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 426                 if (err)
 427                         goto out;
 428
 429                 err = ubi_check_pattern(ubi->peb_buf, 0xFF, ubi->peb_size);
 430                 if (err == 0) {
 431                         ubi_err("erased PEB %d, but a non-0xFF byte found",
 432                                 pnum);
 433                         err = -EIO;
 434                         goto out;
 435                 }
 436
 437                 /* Write a pattern and check it */
 438                 memset(ubi->peb_buf, patterns[i], ubi->peb_size);
 439                 err = ubi_io_write(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 440                 if (err)
 441                         goto out;
 442
 443                 memset(ubi->peb_buf, ~patterns[i], ubi->peb_size);
 444                 err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 445                 if (err)
 446                         goto out;
 447
 448                 err = ubi_check_pattern(ubi->peb_buf, patterns[i],
 449                                         ubi->peb_size);
 450                 if (err == 0) {
 451                         ubi_err("pattern %x checking failed for PEB %d",
 452                                 patterns[i], pnum);
 453                         err = -EIO;
 454                         goto out;
 455                 }
 456         }
 457
 458         err = patt_count;
 459         ubi_msg("PEB %d passed torture test, do not mark it as bad", pnum);
 460
 461 out:
 462         mutex_unlock(&ubi->buf_mutex);
 463         if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err)) {
 464                 /*
 465                  * If a bit-flip or data integrity error was detected, the test
 466                  * has not passed because it happened on a freshly erased
 467                  * physical eraseblock which means something is wrong with it.
 468                  */
 469                 ubi_err("read problems on freshly erased PEB %d, must be bad",
 470                         pnum);
 471                 err = -EIO;
 472         }
 473         return err;
 474 }
 475
 476 /**
 477  * nor_erase_prepare - prepare a NOR flash PEB for erasure.
 478  * @ubi: UBI device description object
 479  * @pnum: physical eraseblock number to prepare
 480  *
 481  * NOR flash, or at least some of them, have peculiar embedded PEB erasure
 482  * algorithm: the PEB is first filled with zeroes, then it is erased. And
 483  * filling with zeroes starts from the end of the PEB. This was observed with
 484  * Spansion S29GL512N NOR flash.
 485  *
 486  * This means that in case of a power cut we may end up with intact data at the
 487  * beginning of the PEB, and all zeroes at the end of PEB. In other words, the
 488  * EC and VID headers are OK, but a large chunk of data at the end of PEB is
 489  * zeroed. This makes UBI mistakenly treat this PEB as used and associate it
 490  * with an LEB, which leads to subsequent failures (e.g., UBIFS fails).
 491  *
 492  * This function is called before erasing NOR PEBs and it zeroes out EC and VID
 493  * magic numbers in order to invalidate them and prevent the failures. Returns
 494  * zero in case of success and a negative error code in case of failure.
 495  */
 496 static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 497 {
 498         int err, err1;
 499         size_t written;
 500         loff_t addr;
 501         uint32_t data = 0;
 502         /*
 503          * Note, we cannot generally define VID header buffers on stack,
 504          * because of the way we deal with these buffers (see the header
 505          * comment in this file). But we know this is a NOR-specific piece of
 506          * code, so we can do this. But yes, this is error-prone and we should
 507          * (pre-)allocate VID header buffer instead.
 508          */
 509         struct ubi_vid_hdr vid_hdr;
 510
 511         /*
 512          * It is important to first invalidate the EC header, and then the VID
 513          * header. Otherwise a power cut may lead to valid EC header and
 514          * invalid VID header, in which case UBI will treat this PEB as
 515          * corrupted and will try to preserve it, and print scary warnings.
 516          */
 517         addr = (loff_t)pnum * ubi->peb_size;
 518         err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
 519         if (!err) {
 520                 addr += ubi->vid_hdr_aloffset;
 521                 err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
 522                 if (!err)
 523                         return 0;
 524         }
 525
 526         /*
 527          * We failed to write to the media. This was observed with Spansion
 528          * S29GL512N NOR flash. Most probably the previously eraseblock erasure
 529          * was interrupted at a very inappropriate moment, so it became
 530          * unwritable. In this case we probably anyway have garbage in this
 531          * PEB.
 532          */
 533         err1 = ubi_io_read_vid_hdr(ubi, pnum, &vid_hdr, 0);
 534         if (err1 == UBI_IO_BAD_HDR_EBADMSG || err1 == UBI_IO_BAD_HDR ||
 535             err1 == UBI_IO_FF) {
 536                 struct ubi_ec_hdr ec_hdr;
 537
 538                 err1 = ubi_io_read_ec_hdr(ubi, pnum, &ec_hdr, 0);
 539                 if (err1 == UBI_IO_BAD_HDR_EBADMSG || err1 == UBI_IO_BAD_HDR ||
 540                     err1 == UBI_IO_FF)
 541                         /*
 542                          * Both VID and EC headers are corrupted, so we can
 543                          * safely erase this PEB and not afraid that it will be
 544                          * treated as a valid PEB in case of an unclean reboot.
 545                          */
 546                         return 0;
 547         }
 548
 549         /*
 550          * The PEB contains a valid VID header, but we cannot invalidate it.
 551          * Supposedly the flash media or the driver is screwed up, so return an
 552          * error.
 553          */
 554         ubi_err("cannot invalidate PEB %d, write returned %d read returned %d",
 555                 pnum, err, err1);
 556         ubi_dump_flash(ubi, pnum, 0, ubi->peb_size);
 557         return -EIO;
 558 }
 559
 560 /**
 561  * ubi_io_sync_erase - synchronously erase a physical eraseblock.
 562  * @ubi: UBI device description object
 563  * @pnum: physical eraseblock number to erase
 564  * @torture: if this physical eraseblock has to be tortured
 565  *
 566  * This function synchronously erases physical eraseblock @pnum. If @torture
 567  * flag is not zero, the physical eraseblock is checked by means of writing
 568  * different patterns to it and reading them back. If the torturing is enabled,
 569  * the physical eraseblock is erased more than once.
 570  *
 571  * This function returns the number of erasures made in case of success, %-EIO
 572  * if the erasure failed or the torturing test failed, and other negative error
 573  * codes in case of other errors. Note, %-EIO means that the physical
 574  * eraseblock is bad.
 575  */
 576 int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
 577 {
 578         int err, ret = 0;
 579
 580         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 581
 582         err = self_check_not_bad(ubi, pnum);
 583         if (err != 0)
 584                 return err;
 585
 586         if (ubi->ro_mode) {
 587                 ubi_err("read-only mode");
 588                 return -EROFS;
 589         }
 590
 591         if (ubi->nor_flash) {
 592                 err = nor_erase_prepare(ubi, pnum);
 593                 if (err)
 594                         return err;
 595         }
 596
 597         if (torture) {
 598                 ret = torture_peb(ubi, pnum);
 599                 if (ret < 0)
 600                         return ret;
 601         }
 602
 603         err = do_sync_erase(ubi, pnum);
 604         if (err)
 605                 return err;
 606
 607         return ret + 1;
 608 }
 609
 610 /**
 611  * ubi_io_is_bad - check if a physical eraseblock is bad.
 612  * @ubi: UBI device description object
 613  * @pnum: the physical eraseblock number to check
 614  *
 615  * This function returns a positive number if the physical eraseblock is bad,
 616  * zero if not, and a negative error code if an error occurred.
 617  */
 618 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum)
 619 {
 620         struct mtd_info *mtd = ubi->mtd;
 621
 622         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 623
 624         if (ubi->bad_allowed) {
 625                 int ret;
 626
 627                 ret = mtd_block_isbad(mtd, (loff_t)pnum * ubi->peb_size);
 628                 if (ret < 0)
 629                         ubi_err("error %d while checking if PEB %d is bad",
 630                                 ret, pnum);
 631                 else if (ret)
 632                         dbg_io("PEB %d is bad", pnum);
 633                 return ret;
 634         }
 635
 636         return 0;
 637 }
 638
 639 /**
 640  * ubi_io_mark_bad - mark a physical eraseblock as bad.
 641  * @ubi: UBI device description object
 642  * @pnum: the physical eraseblock number to mark
 643  *
 644  * This function returns zero in case of success and a negative error code in
 645  * case of failure.
 646  */
 647 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
 648 {
 649         int err;
 650         struct mtd_info *mtd = ubi->mtd;
 651
 652         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 653
 654         if (ubi->ro_mode) {
 655                 ubi_err("read-only mode");
 656                 return -EROFS;
 657         }
 658
 659         if (!ubi->bad_allowed)
 660                 return 0;
 661
 662         err = mtd_block_markbad(mtd, (loff_t)pnum * ubi->peb_size);
 663         if (err)
 664                 ubi_err("cannot mark PEB %d bad, error %d", pnum, err);
 665         return err;
 666 }
 667
 668 /**
 669  * validate_ec_hdr - validate an erase counter header.
 670  * @ubi: UBI device description object
 671  * @ec_hdr: the erase counter header to check
 672  *
 673  * This function returns zero if the erase counter header is OK, and %1 if
 674  * not.
 675  */
 676 static int validate_ec_hdr(const struct ubi_device *ubi,
 677                            const struct ubi_ec_hdr *ec_hdr)
 678 {
 679         long long ec;
 680         int vid_hdr_offset, leb_start;
 681
 682         ec = be64_to_cpu(ec_hdr->ec);
 683         vid_hdr_offset = be32_to_cpu(ec_hdr->vid_hdr_offset);
 684         leb_start = be32_to_cpu(ec_hdr->data_offset);
 685
 686         if (ec_hdr->version != UBI_VERSION) {
 687                 ubi_err("node with incompatible UBI version found: this UBI version is %d, image version is %d",
 688                         UBI_VERSION, (int)ec_hdr->version);
 689                 goto bad;
 690         }
 691
 692         if (vid_hdr_offset != ubi->vid_hdr_offset) {
 693                 ubi_err("bad VID header offset %d, expected %d",
 694                         vid_hdr_offset, ubi->vid_hdr_offset);
 695                 goto bad;
 696         }
 697
 698         if (leb_start != ubi->leb_start) {
 699                 ubi_err("bad data offset %d, expected %d",
 700                         leb_start, ubi->leb_start);
 701                 goto bad;
 702         }
 703
 704         if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
 705                 ubi_err("bad erase counter %lld", ec);
 706                 goto bad;
 707         }
 708
 709         return 0;
 710
 711 bad:
 712         ubi_err("bad EC header");
 713         ubi_dump_ec_hdr(ec_hdr);
 714         dump_stack();
 715         return 1;
 716 }
 717
 718 /**
 719  * ubi_io_read_ec_hdr - read and check an erase counter header.
 720  * @ubi: UBI device description object
 721  * @pnum: physical eraseblock to read from
 722  * @ec_hdr: a &struct ubi_ec_hdr object where to store the read erase counter
 723  * header
 724  * @verbose: be verbose if the header is corrupted or was not found
 725  *
 726  * This function reads erase counter header from physical eraseblock @pnum and
 727  * stores it in @ec_hdr. This function also checks CRC checksum of the read
 728  * erase counter header. The following codes may be returned:
 729  *
 730  * o %0 if the CRC checksum is correct and the header was successfully read;
 731  * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 732  *   and corrected by the flash driver; this is harmless but may indicate that
 733  *   this eraseblock may become bad soon (but may be not);
 734  * o %UBI_IO_BAD_HDR if the erase counter header is corrupted (a CRC error);
 735  * o %UBI_IO_BAD_HDR_EBADMSG is the same as %UBI_IO_BAD_HDR, but there also was
 736  *   a data integrity error (uncorrectable ECC error in case of NAND);
 737  * o %UBI_IO_FF if only 0xFF bytes were read (the PEB is supposedly empty)
 738  * o a negative error code in case of failure.
 739  */
 740 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 741                        struct ubi_ec_hdr *ec_hdr, int verbose)
 742 {
 743         int err, read_err;
 744         uint32_t crc, magic, hdr_crc;
 745
 746         dbg_io("read EC header from PEB %d", pnum);
 747         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 748
 749         read_err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
 750         if (read_err) {
 751                 if (read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
 752                         return read_err;
 753
 754                 /*
 755                  * We read all the data, but either a correctable bit-flip
 756                  * occurred, or MTD reported a data integrity error
 757                  * (uncorrectable ECC error in case of NAND). The former is
 758                  * harmless, the later may mean that the read data is
 759                  * corrupted. But we have a CRC check-sum and we will detect
 760                  * this. If the EC header is still OK, we just report this as
 761                  * there was a bit-flip, to force scrubbing.
 762                  */
 763         }
 764
 765         magic = be32_to_cpu(ec_hdr->magic);
 766         if (magic != UBI_EC_HDR_MAGIC) {
 767                 if (mtd_is_eccerr(read_err))
 768                         return UBI_IO_BAD_HDR_EBADMSG;
 769
 770                 /*
 771                  * The magic field is wrong. Let's check if we have read all
 772                  * 0xFF. If yes, this physical eraseblock is assumed to be
 773                  * empty.
 774                  */
 775                 if (ubi_check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
 776                         /* The physical eraseblock is supposedly empty */
 777                         if (verbose)
 778                                 ubi_warn("no EC header found at PEB %d, only 0xFF bytes",
 779                                          pnum);
 780                         dbg_bld("no EC header found at PEB %d, only 0xFF bytes",
 781                                 pnum);
 782                         if (!read_err)
 783                                 return UBI_IO_FF;
 784                         else
 785                                 return UBI_IO_FF_BITFLIPS;
 786                 }
 787
 788                 /*
 789                  * This is not a valid erase counter header, and these are not
 790                  * 0xFF bytes. Report that the header is corrupted.
 791                  */
 792                 if (verbose) {
 793                         ubi_warn("bad magic number at PEB %d: %08x instead of %08x",
 794                                  pnum, magic, UBI_EC_HDR_MAGIC);
 795                         ubi_dump_ec_hdr(ec_hdr);
 796                 }
 797                 dbg_bld("bad magic number at PEB %d: %08x instead of %08x",
 798                         pnum, magic, UBI_EC_HDR_MAGIC);
 799                 return UBI_IO_BAD_HDR;
 800         }
 801
 802         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 803         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
 804
 805         if (hdr_crc != crc) {
 806                 if (verbose) {
 807                         ubi_warn("bad EC header CRC at PEB %d, calculated %#08x, read %#08x",
 808                                  pnum, crc, hdr_crc);
 809                         ubi_dump_ec_hdr(ec_hdr);
 810                 }
 811                 dbg_bld("bad EC header CRC at PEB %d, calculated %#08x, read %#08x",
 812                         pnum, crc, hdr_crc);
 813
 814                 if (!read_err)
 815                         return UBI_IO_BAD_HDR;
 816                 else
 817                         return UBI_IO_BAD_HDR_EBADMSG;
 818         }
 819
 820         /* And of course validate what has just been read from the media */
 821         err = validate_ec_hdr(ubi, ec_hdr);
 822         if (err) {
 823                 ubi_err("validation failed for PEB %d", pnum);
 824                 return -EINVAL;
 825         }
 826
 827         /*
 828          * If there was %-EBADMSG, but the header CRC is still OK, report about
 829          * a bit-flip to force scrubbing on this PEB.
 830          */
 831         return read_err ? UBI_IO_BITFLIPS : 0;
 832 }
 833
 834 /**
 835  * ubi_io_write_ec_hdr - write an erase counter header.
 836  * @ubi: UBI device description object
 837  * @pnum: physical eraseblock to write to
 838  * @ec_hdr: the erase counter header to write
 839  *
 840  * This function writes erase counter header described by @ec_hdr to physical
 841  * eraseblock @pnum. It also fills most fields of @ec_hdr before writing, so
 842  * the caller do not have to fill them. Callers must only fill the @ec_hdr->ec
 843  * field.
 844  *
 845  * This function returns zero in case of success and a negative error code in
 846  * case of failure. If %-EIO is returned, the physical eraseblock most probably
 847  * went bad.
 848  */
 849 int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 850                         struct ubi_ec_hdr *ec_hdr)
 851 {
 852         int err;
 853         uint32_t crc;
 854
 855         dbg_io("write EC header to PEB %d", pnum);
 856         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 857
 858         ec_hdr->magic = cpu_to_be32(UBI_EC_HDR_MAGIC);
 859         ec_hdr->version = UBI_VERSION;
 860         ec_hdr->vid_hdr_offset = cpu_to_be32(ubi->vid_hdr_offset);
 861         ec_hdr->data_offset = cpu_to_be32(ubi->leb_start);
 862         ec_hdr->image_seq = cpu_to_be32(ubi->image_seq);
 863         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 864         ec_hdr->hdr_crc = cpu_to_be32(crc);
 865
 866         err = self_check_ec_hdr(ubi, pnum, ec_hdr);
 867         if (err)
 868                 return err;
 869
 870         err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
 871         return err;
 872 }
 873
 874 /**
 875  * validate_vid_hdr - validate a volume identifier header.
 876  * @ubi: UBI device description object
 877  * @vid_hdr: the volume identifier header to check
 878  *
 879  * This function checks that data stored in the volume identifier header
 880  * @vid_hdr. Returns zero if the VID header is OK and %1 if not.
 881  */
 882 static int validate_vid_hdr(const struct ubi_device *ubi,
 883                             const struct ubi_vid_hdr *vid_hdr)
 884 {
 885         int vol_type = vid_hdr->vol_type;
 886         int copy_flag = vid_hdr->copy_flag;
 887         int vol_id = be32_to_cpu(vid_hdr->vol_id);
 888         int lnum = be32_to_cpu(vid_hdr->lnum);
 889         int compat = vid_hdr->compat;
 890         int data_size = be32_to_cpu(vid_hdr->data_size);
 891         int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
 892         int data_pad = be32_to_cpu(vid_hdr->data_pad);
 893         int data_crc = be32_to_cpu(vid_hdr->data_crc);
 894         int usable_leb_size = ubi->leb_size - data_pad;
 895
 896         if (copy_flag != 0 && copy_flag != 1) {
 897                 ubi_err("bad copy_flag");
 898                 goto bad;
 899         }
 900
 901         if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
 902             data_pad < 0) {
 903                 ubi_err("negative values");
 904                 goto bad;
 905         }
 906
 907         if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
 908                 ubi_err("bad vol_id");
 909                 goto bad;
 910         }
 911
 912         if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
 913                 ubi_err("bad compat");
 914                 goto bad;
 915         }
 916
 917         if (vol_id >= UBI_INTERNAL_VOL_START && compat != UBI_COMPAT_DELETE &&
 918             compat != UBI_COMPAT_RO && compat != UBI_COMPAT_PRESERVE &&
 919             compat != UBI_COMPAT_REJECT) {
 920                 ubi_err("bad compat");
 921                 goto bad;
 922         }
 923
 924         if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
 925                 ubi_err("bad vol_type");
 926                 goto bad;
 927         }
 928
 929         if (data_pad >= ubi->leb_size / 2) {
 930                 ubi_err("bad data_pad");
 931                 goto bad;
 932         }
 933
 934         if (vol_type == UBI_VID_STATIC) {
 935                 /*
 936                  * Although from high-level point of view static volumes may
 937                  * contain zero bytes of data, but no VID headers can contain
 938                  * zero at these fields, because they empty volumes do not have
 939                  * mapped logical eraseblocks.
 940                  */
 941                 if (used_ebs == 0) {
 942                         ubi_err("zero used_ebs");
 943                         goto bad;
 944                 }
 945                 if (data_size == 0) {
 946                         ubi_err("zero data_size");
 947                         goto bad;
 948                 }
 949                 if (lnum < used_ebs - 1) {
 950                         if (data_size != usable_leb_size) {
 951                                 ubi_err("bad data_size");
 952                                 goto bad;
 953                         }
 954                 } else if (lnum == used_ebs - 1) {
 955                         if (data_size == 0) {
 956                                 ubi_err("bad data_size at last LEB");
 957                                 goto bad;
 958                         }
 959                 } else {
 960                         ubi_err("too high lnum");
 961                         goto bad;
 962                 }
 963         } else {
 964                 if (copy_flag == 0) {
 965                         if (data_crc != 0) {
 966                                 ubi_err("non-zero data CRC");
 967                                 goto bad;
 968                         }
 969                         if (data_size != 0) {
 970                                 ubi_err("non-zero data_size");
 971                                 goto bad;
 972                         }
 973                 } else {
 974                         if (data_size == 0) {
 975                                 ubi_err("zero data_size of copy");
 976                                 goto bad;
 977                         }
 978                 }
 979                 if (used_ebs != 0) {
 980                         ubi_err("bad used_ebs");
 981                         goto bad;
 982                 }
 983         }
 984
 985         return 0;
 986
 987 bad:
 988         ubi_err("bad VID header");
 989         ubi_dump_vid_hdr(vid_hdr);
 990         dump_stack();
 991         return 1;
 992 }
 993
 994 /**
 995  * ubi_io_read_vid_hdr - read and check a volume identifier header.
 996  * @ubi: UBI device description object
 997  * @pnum: physical eraseblock number to read from
 998  * @vid_hdr: &struct ubi_vid_hdr object where to store the read volume
 999  * identifier header
1000  * @verbose: be verbose if the header is corrupted or wasn't found
1001  *
1002  * This function reads the volume identifier header from physical eraseblock
1003  * @pnum and stores it in @vid_hdr. It also checks CRC checksum of the read
1004  * volume identifier header. The error codes are the same as in
1005  * 'ubi_io_read_ec_hdr()'.
1006  *
1007  * Note, the implementation of this function is also very similar to
1008  * 'ubi_io_read_ec_hdr()', so refer commentaries in 'ubi_io_read_ec_hdr()'.
1009  */
1010 int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
1011                         struct ubi_vid_hdr *vid_hdr, int verbose)
1012 {
1013         int err, read_err;
1014         uint32_t crc, magic, hdr_crc;
1015         void *p;
1016
1017         dbg_io("read VID header from PEB %d", pnum);
1018         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
1019
1020         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1021         read_err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1022                           ubi->vid_hdr_alsize);
1023         if (read_err && read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
1024                 return read_err;
1025
1026         magic = be32_to_cpu(vid_hdr->magic);
1027         if (magic != UBI_VID_HDR_MAGIC) {
1028                 if (mtd_is_eccerr(read_err))
1029                         return UBI_IO_BAD_HDR_EBADMSG;
1030
1031                 if (ubi_check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
1032                         if (verbose)
1033                                 ubi_warn("no VID header found at PEB %d, only 0xFF bytes",
1034                                          pnum);
1035                         dbg_bld("no VID header found at PEB %d, only 0xFF bytes",
1036                                 pnum);
1037                         if (!read_err)
1038                                 return UBI_IO_FF;
1039                         else
1040                                 return UBI_IO_FF_BITFLIPS;
1041                 }
1042
1043                 if (verbose) {
1044                         ubi_warn("bad magic number at PEB %d: %08x instead of %08x",
1045                                  pnum, magic, UBI_VID_HDR_MAGIC);
1046                         ubi_dump_vid_hdr(vid_hdr);
1047                 }
1048                 dbg_bld("bad magic number at PEB %d: %08x instead of %08x",
1049                         pnum, magic, UBI_VID_HDR_MAGIC);
1050                 return UBI_IO_BAD_HDR;
1051         }
1052
1053         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1054         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1055
1056         if (hdr_crc != crc) {
1057                 if (verbose) {
1058                         ubi_warn("bad CRC at PEB %d, calculated %#08x, read %#08x",
1059                                  pnum, crc, hdr_crc);
1060                         ubi_dump_vid_hdr(vid_hdr);
1061                 }
1062                 dbg_bld("bad CRC at PEB %d, calculated %#08x, read %#08x",
1063                         pnum, crc, hdr_crc);
1064                 if (!read_err)
1065                         return UBI_IO_BAD_HDR;
1066                 else
1067                         return UBI_IO_BAD_HDR_EBADMSG;
1068         }
1069
1070         err = validate_vid_hdr(ubi, vid_hdr);
1071         if (err) {
1072                 ubi_err("validation failed for PEB %d", pnum);
1073                 return -EINVAL;
1074         }
1075
1076         return read_err ? UBI_IO_BITFLIPS : 0;
1077 }
1078
1079 /**
1080  * ubi_io_write_vid_hdr - write a volume identifier header.
1081  * @ubi: UBI device description object
1082  * @pnum: the physical eraseblock number to write to
1083  * @vid_hdr: the volume identifier header to write
1084  *
1085  * This function writes the volume identifier header described by @vid_hdr to
1086  * physical eraseblock @pnum. This function automatically fills the
1087  * @vid_hdr->magic and the @vid_hdr->version fields, as well as calculates
1088  * header CRC checksum and stores it at vid_hdr->hdr_crc.
1089  *
1090  * This function returns zero in case of success and a negative error code in
1091  * case of failure. If %-EIO is returned, the physical eraseblock probably went
1092  * bad.
1093  */
1094 int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
1095                          struct ubi_vid_hdr *vid_hdr)
1096 {
1097         int err;
1098         uint32_t crc;
1099         void *p;
1100
1101         dbg_io("write VID header to PEB %d", pnum);
1102         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
1103
1104         err = self_check_peb_ec_hdr(ubi, pnum);
1105         if (err)
1106                 return err;
1107
1108         vid_hdr->magic = cpu_to_be32(UBI_VID_HDR_MAGIC);
1109         vid_hdr->version = UBI_VERSION;
1110         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1111         vid_hdr->hdr_crc = cpu_to_be32(crc);
1112
1113         err = self_check_vid_hdr(ubi, pnum, vid_hdr);
1114         if (err)
1115                 return err;
1116
1117         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1118         err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
1119                            ubi->vid_hdr_alsize);
1120         return err;
1121 }
1122
1123 /**
1124  * self_check_not_bad - ensure that a physical eraseblock is not bad.
1125  * @ubi: UBI device description object
1126  * @pnum: physical eraseblock number to check
1127  *
1128  * This function returns zero if the physical eraseblock is good, %-EINVAL if
1129  * it is bad and a negative error code if an error occurred.
1130  */
1131 static int self_check_not_bad(const struct ubi_device *ubi, int pnum)
1132 {
1133         int err;
1134
1135         if (!ubi_dbg_chk_io(ubi))
1136                 return 0;
1137
1138         err = ubi_io_is_bad(ubi, pnum);
1139         if (!err)
1140                 return err;
1141
1142         ubi_err("self-check failed for PEB %d", pnum);
1143         dump_stack();
1144         return err > 0 ? -EINVAL : err;
1145 }
1146
1147 /**
1148  * self_check_ec_hdr - check if an erase counter header is all right.
1149  * @ubi: UBI device description object
1150  * @pnum: physical eraseblock number the erase counter header belongs to
1151  * @ec_hdr: the erase counter header to check
1152  *
1153  * This function returns zero if the erase counter header contains valid
1154  * values, and %-EINVAL if not.
1155  */
1156 static int self_check_ec_hdr(const struct ubi_device *ubi, int pnum,
1157                              const struct ubi_ec_hdr *ec_hdr)
1158 {
1159         int err;
1160         uint32_t magic;
1161
1162         if (!ubi_dbg_chk_io(ubi))
1163                 return 0;
1164
1165         magic = be32_to_cpu(ec_hdr->magic);
1166         if (magic != UBI_EC_HDR_MAGIC) {
1167                 ubi_err("bad magic %#08x, must be %#08x",
1168                         magic, UBI_EC_HDR_MAGIC);
1169                 goto fail;
1170         }
1171
1172         err = validate_ec_hdr(ubi, ec_hdr);
1173         if (err) {
1174                 ubi_err("self-check failed for PEB %d", pnum);
1175                 goto fail;
1176         }
1177
1178         return 0;
1179
1180 fail:
1181         ubi_dump_ec_hdr(ec_hdr);
1182         dump_stack();
1183         return -EINVAL;
1184 }
1185
1186 /**
1187  * self_check_peb_ec_hdr - check erase counter header.
1188  * @ubi: UBI device description object
1189  * @pnum: the physical eraseblock number to check
1190  *
1191  * This function returns zero if the erase counter header is all right and and
1192  * a negative error code if not or if an error occurred.
1193  */
1194 static int self_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
1195 {
1196         int err;
1197         uint32_t crc, hdr_crc;
1198         struct ubi_ec_hdr *ec_hdr;
1199
1200         if (!ubi_dbg_chk_io(ubi))
1201                 return 0;
1202
1203         ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
1204         if (!ec_hdr)
1205                 return -ENOMEM;
1206
1207         err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
1208         if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
1209                 goto exit;
1210
1211         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
1212         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
1213         if (hdr_crc != crc) {
1214                 ubi_err("bad CRC, calculated %#08x, read %#08x", crc, hdr_crc);
1215                 ubi_err("self-check failed for PEB %d", pnum);
1216                 ubi_dump_ec_hdr(ec_hdr);
1217                 dump_stack();
1218                 err = -EINVAL;
1219                 goto exit;
1220         }
1221
1222         err = self_check_ec_hdr(ubi, pnum, ec_hdr);
1223
1224 exit:
1225         kfree(ec_hdr);
1226         return err;
1227 }
1228
1229 /**
1230  * self_check_vid_hdr - check that a volume identifier header is all right.
1231  * @ubi: UBI device description object
1232  * @pnum: physical eraseblock number the volume identifier header belongs to
1233  * @vid_hdr: the volume identifier header to check
1234  *
1235  * This function returns zero if the volume identifier header is all right, and
1236  * %-EINVAL if not.
1237  */
1238 static int self_check_vid_hdr(const struct ubi_device *ubi, int pnum,
1239                               const struct ubi_vid_hdr *vid_hdr)
1240 {
1241         int err;
1242         uint32_t magic;
1243
1244         if (!ubi_dbg_chk_io(ubi))
1245                 return 0;
1246
1247         magic = be32_to_cpu(vid_hdr->magic);
1248         if (magic != UBI_VID_HDR_MAGIC) {
1249                 ubi_err("bad VID header magic %#08x at PEB %d, must be %#08x",
1250                         magic, pnum, UBI_VID_HDR_MAGIC);
1251                 goto fail;
1252         }
1253
1254         err = validate_vid_hdr(ubi, vid_hdr);
1255         if (err) {
1256                 ubi_err("self-check failed for PEB %d", pnum);
1257                 goto fail;
1258         }
1259
1260         return err;
1261
1262 fail:
1263         ubi_err("self-check failed for PEB %d", pnum);
1264         ubi_dump_vid_hdr(vid_hdr);
1265         dump_stack();
1266         return -EINVAL;
1267
1268 }
1269
1270 /**
1271  * self_check_peb_vid_hdr - check volume identifier header.
1272  * @ubi: UBI device description object
1273  * @pnum: the physical eraseblock number to check
1274  *
1275  * This function returns zero if the volume identifier header is all right,
1276  * and a negative error code if not or if an error occurred.
1277  */
1278 static int self_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
1279 {
1280         int err;
1281         uint32_t crc, hdr_crc;
1282         struct ubi_vid_hdr *vid_hdr;
1283         void *p;
1284
1285         if (!ubi_dbg_chk_io(ubi))
1286                 return 0;
1287
1288         vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
1289         if (!vid_hdr)
1290                 return -ENOMEM;
1291
1292         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1293         err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1294                           ubi->vid_hdr_alsize);
1295         if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
1296                 goto exit;
1297
1298         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_EC_HDR_SIZE_CRC);
1299         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1300         if (hdr_crc != crc) {
1301                 ubi_err("bad VID header CRC at PEB %d, calculated %#08x, read %#08x",
1302                         pnum, crc, hdr_crc);
1303                 ubi_err("self-check failed for PEB %d", pnum);
1304                 ubi_dump_vid_hdr(vid_hdr);
1305                 dump_stack();
1306                 err = -EINVAL;
1307                 goto exit;
1308         }
1309
1310         err = self_check_vid_hdr(ubi, pnum, vid_hdr);
1311
1312 exit:
1313         ubi_free_vid_hdr(ubi, vid_hdr);
1314         return err;
1315 }
1316
1317 /**
1318  * self_check_write - make sure write succeeded.
1319  * @ubi: UBI device description object
1320  * @buf: buffer with data which were written
1321  * @pnum: physical eraseblock number the data were written to
1322  * @offset: offset within the physical eraseblock the data were written to
1323  * @len: how many bytes were written
1324  *
1325  * This functions reads data which were recently written and compares it with
1326  * the original data buffer - the data have to match. Returns zero if the data
1327  * match and a negative error code if not or in case of failure.
1328  */
1329 static int self_check_write(struct ubi_device *ubi, const void *buf, int pnum,
1330                             int offset, int len)
1331 {
1332         int err, i;
1333         size_t read;
1334         void *buf1;
1335         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1336
1337         if (!ubi_dbg_chk_io(ubi))
1338                 return 0;
1339
1340         buf1 = __vmalloc(len, GFP_NOFS, PAGE_KERNEL);
1341         if (!buf1) {
1342                 ubi_err("cannot allocate memory to check writes");
1343                 return 0;
1344         }
1345
1346         err = mtd_read(ubi->mtd, addr, len, &read, buf1);
1347         if (err && !mtd_is_bitflip(err))
1348                 goto out_free;
1349
1350         for (i = 0; i < len; i++) {
1351                 uint8_t c = ((uint8_t *)buf)[i];
1352                 uint8_t c1 = ((uint8_t *)buf1)[i];
1353                 int dump_len;
1354
1355                 if (c == c1)
1356                         continue;
1357
1358                 ubi_err("self-check failed for PEB %d:%d, len %d",
1359                         pnum, offset, len);
1360                 ubi_msg("data differ at position %d", i);
1361                 dump_len = max_t(int, 128, len - i);
1362                 ubi_msg("hex dump of the original buffer from %d to %d",
1363                         i, i + dump_len);
1364                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1365                                buf + i, dump_len, 1);
1366                 ubi_msg("hex dump of the read buffer from %d to %d",
1367                         i, i + dump_len);
1368                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1369                                buf1 + i, dump_len, 1);
1370                 dump_stack();
1371                 err = -EINVAL;
1372                 goto out_free;
1373         }
1374
1375         vfree(buf1);
1376         return 0;
1377
1378 out_free:
1379         vfree(buf1);
1380         return err;
1381 }
1382
1383 /**
1384  * ubi_self_check_all_ff - check that a region of flash is empty.
1385  * @ubi: UBI device description object
1386  * @pnum: the physical eraseblock number to check
1387  * @offset: the starting offset within the physical eraseblock to check
1388  * @len: the length of the region to check
1389  *
1390  * This function returns zero if only 0xFF bytes are present at offset
1391  * @offset of the physical eraseblock @pnum, and a negative error code if not
1392  * or if an error occurred.
1393  */
1394 int ubi_self_check_all_ff(struct ubi_device *ubi, int pnum, int offset, int len)
1395 {
1396         size_t read;
1397         int err;
1398         void *buf;
1399         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1400
1401         if (!ubi_dbg_chk_io(ubi))
1402                 return 0;
1403
1404         buf = __vmalloc(len, GFP_NOFS, PAGE_KERNEL);
1405         if (!buf) {
1406                 ubi_err("cannot allocate memory to check for 0xFFs");
1407                 return 0;
1408         }
1409
1410         err = mtd_read(ubi->mtd, addr, len, &read, buf);
1411         if (err && !mtd_is_bitflip(err)) {
1412                 ubi_err("error %d while reading %d bytes from PEB %d:%d, read %zd bytes",
1413                         err, len, pnum, offset, read);
1414                 goto error;
1415         }
1416
1417         err = ubi_check_pattern(buf, 0xFF, len);
1418         if (err == 0) {
1419                 ubi_err("flash region at PEB %d:%d, length %d does not contain all 0xFF bytes",
1420                         pnum, offset, len);
1421                 goto fail;
1422         }
1423
1424         vfree(buf);
1425         return 0;
1426
1427 fail:
1428         ubi_err("self-check failed for PEB %d", pnum);
1429         ubi_msg("hex dump of the %d-%d region", offset, offset + len);
1430         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, buf, len, 1);
1431         err = -EINVAL;
1432 error:
1433         dump_stack();
1434         vfree(buf);
1435         return err;
1436 }