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(ubi, "fixable bit-flip detected at PEB %d",
 181                                 pnum);
 182                         ubi_assert(len == read);
 183                         return UBI_IO_BITFLIPS;
 184                 }
 185
 186                 if (retries++ < UBI_IO_RETRIES) {
 187                         ubi_warn(ubi, "error %d%s while reading %d bytes from PEB %d:%d, read only %zd bytes, retry",
 188                                  err, errstr, len, pnum, offset, read);
 189                         yield();
 190                         goto retry;
 191                 }
 192
 193                 ubi_err(ubi, "error %d%s while reading %d bytes from PEB %d:%d, read %zd bytes",
 194                         err, errstr, len, pnum, offset, read);
 195                 dump_stack();
 196
 197                 /*
 198                  * The driver should never return -EBADMSG if it failed to read
 199                  * all the requested data. But some buggy drivers might do
 200                  * this, so we change it to -EIO.
 201                  */
 202                 if (read != len && mtd_is_eccerr(err)) {
 203                         ubi_assert(0);
 204                         err = -EIO;
 205                 }
 206         } else {
 207                 ubi_assert(len == read);
 208
 209                 if (ubi_dbg_is_bitflip(ubi)) {
 210                         dbg_gen("bit-flip (emulated)");
 211                         err = UBI_IO_BITFLIPS;
 212                 }
 213         }
 214
 215         return err;
 216 }
 217
 218 /**
 219  * ubi_io_write - write data to a physical eraseblock.
 220  * @ubi: UBI device description object
 221  * @buf: buffer with the data to write
 222  * @pnum: physical eraseblock number to write to
 223  * @offset: offset within the physical eraseblock where to write
 224  * @len: how many bytes to write
 225  *
 226  * This function writes @len bytes of data from buffer @buf to offset @offset
 227  * of physical eraseblock @pnum. If all the data were successfully written,
 228  * zero is returned. If an error occurred, this function returns a negative
 229  * error code. If %-EIO is returned, the physical eraseblock most probably went
 230  * bad.
 231  *
 232  * Note, in case of an error, it is possible that something was still written
 233  * to the flash media, but may be some garbage.
 234  */
 235 int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
 236                  int len)
 237 {
 238         int err;
 239         size_t written;
 240         loff_t addr;
 241
 242         dbg_io("write %d bytes to PEB %d:%d", len, pnum, offset);
 243
 244         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 245         ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 246         ubi_assert(offset % ubi->hdrs_min_io_size == 0);
 247         ubi_assert(len > 0 && len % ubi->hdrs_min_io_size == 0);
 248
 249         if (ubi->ro_mode) {
 250                 ubi_err(ubi, "read-only mode");
 251                 return -EROFS;
 252         }
 253
 254         err = self_check_not_bad(ubi, pnum);
 255         if (err)
 256                 return err;
 257
 258         /* The area we are writing to has to contain all 0xFF bytes */
 259         err = ubi_self_check_all_ff(ubi, pnum, offset, len);
 260         if (err)
 261                 return err;
 262
 263         if (offset >= ubi->leb_start) {
 264                 /*
 265                  * We write to the data area of the physical eraseblock. Make
 266                  * sure it has valid EC and VID headers.
 267                  */
 268                 err = self_check_peb_ec_hdr(ubi, pnum);
 269                 if (err)
 270                         return err;
 271                 err = self_check_peb_vid_hdr(ubi, pnum);
 272                 if (err)
 273                         return err;
 274         }
 275
 276         if (ubi_dbg_is_write_failure(ubi)) {
 277                 ubi_err(ubi, "cannot write %d bytes to PEB %d:%d (emulated)",
 278                         len, pnum, offset);
 279                 dump_stack();
 280                 return -EIO;
 281         }
 282
 283         addr = (loff_t)pnum * ubi->peb_size + offset;
 284         err = mtd_write(ubi->mtd, addr, len, &written, buf);
 285         if (err) {
 286                 ubi_err(ubi, "error %d while writing %d bytes to PEB %d:%d, written %zd bytes",
 287                         err, len, pnum, offset, written);
 288                 dump_stack();
 289                 ubi_dump_flash(ubi, pnum, offset, len);
 290         } else
 291                 ubi_assert(written == len);
 292
 293         if (!err) {
 294                 err = self_check_write(ubi, buf, pnum, offset, len);
 295                 if (err)
 296                         return err;
 297
 298                 /*
 299                  * Since we always write sequentially, the rest of the PEB has
 300                  * to contain only 0xFF bytes.
 301                  */
 302                 offset += len;
 303                 len = ubi->peb_size - offset;
 304                 if (len)
 305                         err = ubi_self_check_all_ff(ubi, pnum, offset, len);
 306         }
 307
 308         return err;
 309 }
 310
 311 /**
 312  * erase_callback - MTD erasure call-back.
 313  * @ei: MTD erase information object.
 314  *
 315  * Note, even though MTD erase interface is asynchronous, all the current
 316  * implementations are synchronous anyway.
 317  */
 318 static void erase_callback(struct erase_info *ei)
 319 {
 320         wake_up_interruptible((wait_queue_head_t *)ei->priv);
 321 }
 322
 323 /**
 324  * do_sync_erase - synchronously erase a physical eraseblock.
 325  * @ubi: UBI device description object
 326  * @pnum: the physical eraseblock number to erase
 327  *
 328  * This function synchronously erases physical eraseblock @pnum and returns
 329  * zero in case of success and a negative error code in case of failure. If
 330  * %-EIO is returned, the physical eraseblock most probably went bad.
 331  */
 332 static int do_sync_erase(struct ubi_device *ubi, int pnum)
 333 {
 334         int err, retries = 0;
 335         struct erase_info ei;
 336         wait_queue_head_t wq;
 337
 338         dbg_io("erase PEB %d", pnum);
 339         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 340
 341         if (ubi->ro_mode) {
 342                 ubi_err(ubi, "read-only mode");
 343                 return -EROFS;
 344         }
 345
 346 retry:
 347         init_waitqueue_head(&wq);
 348         memset(&ei, 0, sizeof(struct erase_info));
 349
 350         ei.mtd      = ubi->mtd;
 351         ei.addr     = (loff_t)pnum * ubi->peb_size;
 352         ei.len      = ubi->peb_size;
 353         ei.callback = erase_callback;
 354         ei.priv     = (unsigned long)&wq;
 355
 356         err = mtd_erase(ubi->mtd, &ei);
 357         if (err) {
 358                 if (retries++ < UBI_IO_RETRIES) {
 359                         ubi_warn(ubi, "error %d while erasing PEB %d, retry",
 360                                  err, pnum);
 361                         yield();
 362                         goto retry;
 363                 }
 364                 ubi_err(ubi, "cannot erase PEB %d, error %d", pnum, err);
 365                 dump_stack();
 366                 return err;
 367         }
 368
 369         err = wait_event_interruptible(wq, ei.state == MTD_ERASE_DONE ||
 370                                            ei.state == MTD_ERASE_FAILED);
 371         if (err) {
 372                 ubi_err(ubi, "interrupted PEB %d erasure", pnum);
 373                 return -EINTR;
 374         }
 375
 376         if (ei.state == MTD_ERASE_FAILED) {
 377                 if (retries++ < UBI_IO_RETRIES) {
 378                         ubi_warn(ubi, "error while erasing PEB %d, retry",
 379                                  pnum);
 380                         yield();
 381                         goto retry;
 382                 }
 383                 ubi_err(ubi, "cannot erase PEB %d", pnum);
 384                 dump_stack();
 385                 return -EIO;
 386         }
 387
 388         err = ubi_self_check_all_ff(ubi, pnum, 0, ubi->peb_size);
 389         if (err)
 390                 return err;
 391
 392         if (ubi_dbg_is_erase_failure(ubi)) {
 393                 ubi_err(ubi, "cannot erase PEB %d (emulated)", pnum);
 394                 return -EIO;
 395         }
 396
 397         return 0;
 398 }
 399
 400 /* Patterns to write to a physical eraseblock when torturing it */
 401 static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
 402
 403 /**
 404  * torture_peb - test a supposedly bad physical eraseblock.
 405  * @ubi: UBI device description object
 406  * @pnum: the physical eraseblock number to test
 407  *
 408  * This function returns %-EIO if the physical eraseblock did not pass the
 409  * test, a positive number of erase operations done if the test was
 410  * successfully passed, and other negative error codes in case of other errors.
 411  */
 412 static int torture_peb(struct ubi_device *ubi, int pnum)
 413 {
 414         int err, i, patt_count;
 415
 416         ubi_msg(ubi, "run torture test for PEB %d", pnum);
 417         patt_count = ARRAY_SIZE(patterns);
 418         ubi_assert(patt_count > 0);
 419
 420         mutex_lock(&ubi->buf_mutex);
 421         for (i = 0; i < patt_count; i++) {
 422                 err = do_sync_erase(ubi, pnum);
 423                 if (err)
 424                         goto out;
 425
 426                 /* Make sure the PEB contains only 0xFF bytes */
 427                 err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 428                 if (err)
 429                         goto out;
 430
 431                 err = ubi_check_pattern(ubi->peb_buf, 0xFF, ubi->peb_size);
 432                 if (err == 0) {
 433                         ubi_err(ubi, "erased PEB %d, but a non-0xFF byte found",
 434                                 pnum);
 435                         err = -EIO;
 436                         goto out;
 437                 }
 438
 439                 /* Write a pattern and check it */
 440                 memset(ubi->peb_buf, patterns[i], ubi->peb_size);
 441                 err = ubi_io_write(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 442                 if (err)
 443                         goto out;
 444
 445                 memset(ubi->peb_buf, ~patterns[i], ubi->peb_size);
 446                 err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size);
 447                 if (err)
 448                         goto out;
 449
 450                 err = ubi_check_pattern(ubi->peb_buf, patterns[i],
 451                                         ubi->peb_size);
 452                 if (err == 0) {
 453                         ubi_err(ubi, "pattern %x checking failed for PEB %d",
 454                                 patterns[i], pnum);
 455                         err = -EIO;
 456                         goto out;
 457                 }
 458         }
 459
 460         err = patt_count;
 461         ubi_msg(ubi, "PEB %d passed torture test, do not mark it as bad", pnum);
 462
 463 out:
 464         mutex_unlock(&ubi->buf_mutex);
 465         if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err)) {
 466                 /*
 467                  * If a bit-flip or data integrity error was detected, the test
 468                  * has not passed because it happened on a freshly erased
 469                  * physical eraseblock which means something is wrong with it.
 470                  */
 471                 ubi_err(ubi, "read problems on freshly erased PEB %d, must be bad",
 472                         pnum);
 473                 err = -EIO;
 474         }
 475         return err;
 476 }
 477
 478 /**
 479  * nor_erase_prepare - prepare a NOR flash PEB for erasure.
 480  * @ubi: UBI device description object
 481  * @pnum: physical eraseblock number to prepare
 482  *
 483  * NOR flash, or at least some of them, have peculiar embedded PEB erasure
 484  * algorithm: the PEB is first filled with zeroes, then it is erased. And
 485  * filling with zeroes starts from the end of the PEB. This was observed with
 486  * Spansion S29GL512N NOR flash.
 487  *
 488  * This means that in case of a power cut we may end up with intact data at the
 489  * beginning of the PEB, and all zeroes at the end of PEB. In other words, the
 490  * EC and VID headers are OK, but a large chunk of data at the end of PEB is
 491  * zeroed. This makes UBI mistakenly treat this PEB as used and associate it
 492  * with an LEB, which leads to subsequent failures (e.g., UBIFS fails).
 493  *
 494  * This function is called before erasing NOR PEBs and it zeroes out EC and VID
 495  * magic numbers in order to invalidate them and prevent the failures. Returns
 496  * zero in case of success and a negative error code in case of failure.
 497  */
 498 static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 499 {
 500         int err;
 501         size_t written;
 502         loff_t addr;
 503         uint32_t data = 0;
 504         struct ubi_ec_hdr ec_hdr;
 505
 506         /*
 507          * Note, we cannot generally define VID header buffers on stack,
 508          * because of the way we deal with these buffers (see the header
 509          * comment in this file). But we know this is a NOR-specific piece of
 510          * code, so we can do this. But yes, this is error-prone and we should
 511          * (pre-)allocate VID header buffer instead.
 512          */
 513         struct ubi_vid_hdr vid_hdr;
 514
 515         /*
 516          * If VID or EC is valid, we have to corrupt them before erasing.
 517          * It is important to first invalidate the EC header, and then the VID
 518          * header. Otherwise a power cut may lead to valid EC header and
 519          * invalid VID header, in which case UBI will treat this PEB as
 520          * corrupted and will try to preserve it, and print scary warnings.
 521          */
 522         addr = (loff_t)pnum * ubi->peb_size;
 523         err = ubi_io_read_ec_hdr(ubi, pnum, &ec_hdr, 0);
 524         if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
 525             err != UBI_IO_FF){
 526                 err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
 527                 if(err)
 528                         goto error;
 529         }
 530
 531         err = ubi_io_read_vid_hdr(ubi, pnum, &vid_hdr, 0);
 532         if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
 533             err != UBI_IO_FF){
 534                 addr += ubi->vid_hdr_aloffset;
 535                 err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
 536                 if (err)
 537                         goto error;
 538         }
 539         return 0;
 540
 541 error:
 542         /*
 543          * The PEB contains a valid VID or EC header, but we cannot invalidate
 544          * it. Supposedly the flash media or the driver is screwed up, so
 545          * return an error.
 546          */
 547         ubi_err(ubi, "cannot invalidate PEB %d, write returned %d", pnum, err);
 548         ubi_dump_flash(ubi, pnum, 0, ubi->peb_size);
 549         return -EIO;
 550 }
 551
 552 /**
 553  * ubi_io_sync_erase - synchronously erase a physical eraseblock.
 554  * @ubi: UBI device description object
 555  * @pnum: physical eraseblock number to erase
 556  * @torture: if this physical eraseblock has to be tortured
 557  *
 558  * This function synchronously erases physical eraseblock @pnum. If @torture
 559  * flag is not zero, the physical eraseblock is checked by means of writing
 560  * different patterns to it and reading them back. If the torturing is enabled,
 561  * the physical eraseblock is erased more than once.
 562  *
 563  * This function returns the number of erasures made in case of success, %-EIO
 564  * if the erasure failed or the torturing test failed, and other negative error
 565  * codes in case of other errors. Note, %-EIO means that the physical
 566  * eraseblock is bad.
 567  */
 568 int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
 569 {
 570         int err, ret = 0;
 571
 572         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 573
 574         err = self_check_not_bad(ubi, pnum);
 575         if (err != 0)
 576                 return err;
 577
 578         if (ubi->ro_mode) {
 579                 ubi_err(ubi, "read-only mode");
 580                 return -EROFS;
 581         }
 582
 583         if (ubi->nor_flash) {
 584                 err = nor_erase_prepare(ubi, pnum);
 585                 if (err)
 586                         return err;
 587         }
 588
 589         if (torture) {
 590                 ret = torture_peb(ubi, pnum);
 591                 if (ret < 0)
 592                         return ret;
 593         }
 594
 595         err = do_sync_erase(ubi, pnum);
 596         if (err)
 597                 return err;
 598
 599         return ret + 1;
 600 }
 601
 602 /**
 603  * ubi_io_is_bad - check if a physical eraseblock is bad.
 604  * @ubi: UBI device description object
 605  * @pnum: the physical eraseblock number to check
 606  *
 607  * This function returns a positive number if the physical eraseblock is bad,
 608  * zero if not, and a negative error code if an error occurred.
 609  */
 610 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum)
 611 {
 612         struct mtd_info *mtd = ubi->mtd;
 613
 614         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 615
 616         if (ubi->bad_allowed) {
 617                 int ret;
 618
 619                 ret = mtd_block_isbad(mtd, (loff_t)pnum * ubi->peb_size);
 620                 if (ret < 0)
 621                         ubi_err(ubi, "error %d while checking if PEB %d is bad",
 622                                 ret, pnum);
 623                 else if (ret)
 624                         dbg_io("PEB %d is bad", pnum);
 625                 return ret;
 626         }
 627
 628         return 0;
 629 }
 630
 631 /**
 632  * ubi_io_mark_bad - mark a physical eraseblock as bad.
 633  * @ubi: UBI device description object
 634  * @pnum: the physical eraseblock number to mark
 635  *
 636  * This function returns zero in case of success and a negative error code in
 637  * case of failure.
 638  */
 639 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
 640 {
 641         int err;
 642         struct mtd_info *mtd = ubi->mtd;
 643
 644         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 645
 646         if (ubi->ro_mode) {
 647                 ubi_err(ubi, "read-only mode");
 648                 return -EROFS;
 649         }
 650
 651         if (!ubi->bad_allowed)
 652                 return 0;
 653
 654         err = mtd_block_markbad(mtd, (loff_t)pnum * ubi->peb_size);
 655         if (err)
 656                 ubi_err(ubi, "cannot mark PEB %d bad, error %d", pnum, err);
 657         return err;
 658 }
 659
 660 /**
 661  * validate_ec_hdr - validate an erase counter header.
 662  * @ubi: UBI device description object
 663  * @ec_hdr: the erase counter header to check
 664  *
 665  * This function returns zero if the erase counter header is OK, and %1 if
 666  * not.
 667  */
 668 static int validate_ec_hdr(const struct ubi_device *ubi,
 669                            const struct ubi_ec_hdr *ec_hdr)
 670 {
 671         long long ec;
 672         int vid_hdr_offset, leb_start;
 673
 674         ec = be64_to_cpu(ec_hdr->ec);
 675         vid_hdr_offset = be32_to_cpu(ec_hdr->vid_hdr_offset);
 676         leb_start = be32_to_cpu(ec_hdr->data_offset);
 677
 678         if (ec_hdr->version != UBI_VERSION) {
 679                 ubi_err(ubi, "node with incompatible UBI version found: this UBI version is %d, image version is %d",
 680                         UBI_VERSION, (int)ec_hdr->version);
 681                 goto bad;
 682         }
 683
 684         if (vid_hdr_offset != ubi->vid_hdr_offset) {
 685                 ubi_err(ubi, "bad VID header offset %d, expected %d",
 686                         vid_hdr_offset, ubi->vid_hdr_offset);
 687                 goto bad;
 688         }
 689
 690         if (leb_start != ubi->leb_start) {
 691                 ubi_err(ubi, "bad data offset %d, expected %d",
 692                         leb_start, ubi->leb_start);
 693                 goto bad;
 694         }
 695
 696         if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
 697                 ubi_err(ubi, "bad erase counter %lld", ec);
 698                 goto bad;
 699         }
 700
 701         return 0;
 702
 703 bad:
 704         ubi_err(ubi, "bad EC header");
 705         ubi_dump_ec_hdr(ec_hdr);
 706         dump_stack();
 707         return 1;
 708 }
 709
 710 /**
 711  * ubi_io_read_ec_hdr - read and check an erase counter header.
 712  * @ubi: UBI device description object
 713  * @pnum: physical eraseblock to read from
 714  * @ec_hdr: a &struct ubi_ec_hdr object where to store the read erase counter
 715  * header
 716  * @verbose: be verbose if the header is corrupted or was not found
 717  *
 718  * This function reads erase counter header from physical eraseblock @pnum and
 719  * stores it in @ec_hdr. This function also checks CRC checksum of the read
 720  * erase counter header. The following codes may be returned:
 721  *
 722  * o %0 if the CRC checksum is correct and the header was successfully read;
 723  * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 724  *   and corrected by the flash driver; this is harmless but may indicate that
 725  *   this eraseblock may become bad soon (but may be not);
 726  * o %UBI_IO_BAD_HDR if the erase counter header is corrupted (a CRC error);
 727  * o %UBI_IO_BAD_HDR_EBADMSG is the same as %UBI_IO_BAD_HDR, but there also was
 728  *   a data integrity error (uncorrectable ECC error in case of NAND);
 729  * o %UBI_IO_FF if only 0xFF bytes were read (the PEB is supposedly empty)
 730  * o a negative error code in case of failure.
 731  */
 732 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 733                        struct ubi_ec_hdr *ec_hdr, int verbose)
 734 {
 735         int err, read_err;
 736         uint32_t crc, magic, hdr_crc;
 737
 738         dbg_io("read EC header from PEB %d", pnum);
 739         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 740
 741         read_err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
 742         if (read_err) {
 743                 if (read_err != UBI_IO_BITFLIPS && !mtd_is_eccerr(read_err))
 744                         return read_err;
 745
 746                 /*
 747                  * We read all the data, but either a correctable bit-flip
 748                  * occurred, or MTD reported a data integrity error
 749                  * (uncorrectable ECC error in case of NAND). The former is
 750                  * harmless, the later may mean that the read data is
 751                  * corrupted. But we have a CRC check-sum and we will detect
 752                  * this. If the EC header is still OK, we just report this as
 753                  * there was a bit-flip, to force scrubbing.
 754                  */
 755         }
 756
 757         magic = be32_to_cpu(ec_hdr->magic);
 758         if (magic != UBI_EC_HDR_MAGIC) {
 759                 if (mtd_is_eccerr(read_err))
 760                         return UBI_IO_BAD_HDR_EBADMSG;
 761
 762                 /*
 763                  * The magic field is wrong. Let's check if we have read all
 764                  * 0xFF. If yes, this physical eraseblock is assumed to be
 765                  * empty.
 766                  */
 767                 if (ubi_check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
 768                         /* The physical eraseblock is supposedly empty */
 769                         if (verbose)
 770                                 ubi_warn(ubi, "no EC header found at PEB %d, only 0xFF bytes",
 771                                          pnum);
 772                         dbg_bld("no EC header found at PEB %d, only 0xFF bytes",
 773                                 pnum);
 774                         if (!read_err)
 775                                 return UBI_IO_FF;
 776                         else
 777                                 return UBI_IO_FF_BITFLIPS;
 778                 }
 779
 780                 /*
 781                  * This is not a valid erase counter header, and these are not
 782                  * 0xFF bytes. Report that the header is corrupted.
 783                  */
 784                 if (verbose) {
 785                         ubi_warn(ubi, "bad magic number at PEB %d: %08x instead of %08x",
 786                                  pnum, magic, UBI_EC_HDR_MAGIC);
 787                         ubi_dump_ec_hdr(ec_hdr);
 788                 }
 789                 dbg_bld("bad magic number at PEB %d: %08x instead of %08x",
 790                         pnum, magic, UBI_EC_HDR_MAGIC);
 791                 return UBI_IO_BAD_HDR;
 792         }
 793
 794         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 795         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
 796
 797         if (hdr_crc != crc) {
 798                 if (verbose) {
 799                         ubi_warn(ubi, "bad EC header CRC at PEB %d, calculated %#08x, read %#08x",
 800                                  pnum, crc, hdr_crc);
 801                         ubi_dump_ec_hdr(ec_hdr);
 802                 }
 803                 dbg_bld("bad EC header CRC at PEB %d, calculated %#08x, read %#08x",
 804                         pnum, crc, hdr_crc);
 805
 806                 if (!read_err)
 807                         return UBI_IO_BAD_HDR;
 808                 else
 809                         return UBI_IO_BAD_HDR_EBADMSG;
 810         }
 811
 812         /* And of course validate what has just been read from the media */
 813         err = validate_ec_hdr(ubi, ec_hdr);
 814         if (err) {
 815                 ubi_err(ubi, "validation failed for PEB %d", pnum);
 816                 return -EINVAL;
 817         }
 818
 819         /*
 820          * If there was %-EBADMSG, but the header CRC is still OK, report about
 821          * a bit-flip to force scrubbing on this PEB.
 822          */
 823         return read_err ? UBI_IO_BITFLIPS : 0;
 824 }
 825
 826 /**
 827  * ubi_io_write_ec_hdr - write an erase counter header.
 828  * @ubi: UBI device description object
 829  * @pnum: physical eraseblock to write to
 830  * @ec_hdr: the erase counter header to write
 831  *
 832  * This function writes erase counter header described by @ec_hdr to physical
 833  * eraseblock @pnum. It also fills most fields of @ec_hdr before writing, so
 834  * the caller do not have to fill them. Callers must only fill the @ec_hdr->ec
 835  * field.
 836  *
 837  * This function returns zero in case of success and a negative error code in
 838  * case of failure. If %-EIO is returned, the physical eraseblock most probably
 839  * went bad.
 840  */
 841 int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 842                         struct ubi_ec_hdr *ec_hdr)
 843 {
 844         int err;
 845         uint32_t crc;
 846
 847         dbg_io("write EC header to PEB %d", pnum);
 848         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 849
 850         ec_hdr->magic = cpu_to_be32(UBI_EC_HDR_MAGIC);
 851         ec_hdr->version = UBI_VERSION;
 852         ec_hdr->vid_hdr_offset = cpu_to_be32(ubi->vid_hdr_offset);
 853         ec_hdr->data_offset = cpu_to_be32(ubi->leb_start);
 854         ec_hdr->image_seq = cpu_to_be32(ubi->image_seq);
 855         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 856         ec_hdr->hdr_crc = cpu_to_be32(crc);
 857
 858         err = self_check_ec_hdr(ubi, pnum, ec_hdr);
 859         if (err)
 860                 return err;
 861
 862         if (ubi_dbg_power_cut(ubi, POWER_CUT_EC_WRITE))
 863                 return -EROFS;
 864
 865         err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
 866         return err;
 867 }
 868
 869 /**
 870  * validate_vid_hdr - validate a volume identifier header.
 871  * @ubi: UBI device description object
 872  * @vid_hdr: the volume identifier header to check
 873  *
 874  * This function checks that data stored in the volume identifier header
 875  * @vid_hdr. Returns zero if the VID header is OK and %1 if not.
 876  */
 877 static int validate_vid_hdr(const struct ubi_device *ubi,
 878                             const struct ubi_vid_hdr *vid_hdr)
 879 {
 880         int vol_type = vid_hdr->vol_type;
 881         int copy_flag = vid_hdr->copy_flag;
 882         int vol_id = be32_to_cpu(vid_hdr->vol_id);
 883         int lnum = be32_to_cpu(vid_hdr->lnum);
 884         int compat = vid_hdr->compat;
 885         int data_size = be32_to_cpu(vid_hdr->data_size);
 886         int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
 887         int data_pad = be32_to_cpu(vid_hdr->data_pad);
 888         int data_crc = be32_to_cpu(vid_hdr->data_crc);
 889         int usable_leb_size = ubi->leb_size - data_pad;
 890
 891         if (copy_flag != 0 && copy_flag != 1) {
 892                 ubi_err(ubi, "bad copy_flag");
 893                 goto bad;
 894         }
 895
 896         if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
 897             data_pad < 0) {
 898                 ubi_err(ubi, "negative values");
 899                 goto bad;
 900         }
 901
 902         if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
 903                 ubi_err(ubi, "bad vol_id");
 904                 goto bad;
 905         }
 906
 907         if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
 908                 ubi_err(ubi, "bad compat");
 909                 goto bad;
 910         }
 911
 912         if (vol_id >= UBI_INTERNAL_VOL_START && compat != UBI_COMPAT_DELETE &&
 913             compat != UBI_COMPAT_RO && compat != UBI_COMPAT_PRESERVE &&
 914             compat != UBI_COMPAT_REJECT) {
 915                 ubi_err(ubi, "bad compat");
 916                 goto bad;
 917         }
 918
 919         if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
 920                 ubi_err(ubi, "bad vol_type");
 921                 goto bad;
 922         }
 923
 924         if (data_pad >= ubi->leb_size / 2) {
 925                 ubi_err(ubi, "bad data_pad");
 926                 goto bad;
 927         }
 928
 929         if (data_size > ubi->leb_size) {
 930                 ubi_err(ubi, "bad data_size");
 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(ubi, "zero used_ebs");
 943                         goto bad;
 944                 }
 945                 if (data_size == 0) {
 946                         ubi_err(ubi, "zero data_size");
 947                         goto bad;
 948                 }
 949                 if (lnum < used_ebs - 1) {
 950                         if (data_size != usable_leb_size) {
 951                                 ubi_err(ubi, "bad data_size");
 952                                 goto bad;
 953                         }
 954                 } else if (lnum == used_ebs - 1) {
 955                         if (data_size == 0) {
 956                                 ubi_err(ubi, "bad data_size at last LEB");
 957                                 goto bad;
 958                         }
 959                 } else {
 960                         ubi_err(ubi, "too high lnum");
 961                         goto bad;
 962                 }
 963         } else {
 964                 if (copy_flag == 0) {
 965                         if (data_crc != 0) {
 966                                 ubi_err(ubi, "non-zero data CRC");
 967                                 goto bad;
 968                         }
 969                         if (data_size != 0) {
 970                                 ubi_err(ubi, "non-zero data_size");
 971                                 goto bad;
 972                         }
 973                 } else {
 974                         if (data_size == 0) {
 975                                 ubi_err(ubi, "zero data_size of copy");
 976                                 goto bad;
 977                         }
 978                 }
 979                 if (used_ebs != 0) {
 980                         ubi_err(ubi, "bad used_ebs");
 981                         goto bad;
 982                 }
 983         }
 984
 985         return 0;
 986
 987 bad:
 988         ubi_err(ubi, "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(ubi, "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(ubi, "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(ubi, "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(ubi, "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         if (ubi_dbg_power_cut(ubi, POWER_CUT_VID_WRITE))
1118                 return -EROFS;
1119
1120         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1121         err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
1122                            ubi->vid_hdr_alsize);
1123         return err;
1124 }
1125
1126 /**
1127  * self_check_not_bad - ensure that a physical eraseblock is not bad.
1128  * @ubi: UBI device description object
1129  * @pnum: physical eraseblock number to check
1130  *
1131  * This function returns zero if the physical eraseblock is good, %-EINVAL if
1132  * it is bad and a negative error code if an error occurred.
1133  */
1134 static int self_check_not_bad(const struct ubi_device *ubi, int pnum)
1135 {
1136         int err;
1137
1138         if (!ubi_dbg_chk_io(ubi))
1139                 return 0;
1140
1141         err = ubi_io_is_bad(ubi, pnum);
1142         if (!err)
1143                 return err;
1144
1145         ubi_err(ubi, "self-check failed for PEB %d", pnum);
1146         dump_stack();
1147         return err > 0 ? -EINVAL : err;
1148 }
1149
1150 /**
1151  * self_check_ec_hdr - check if an erase counter header is all right.
1152  * @ubi: UBI device description object
1153  * @pnum: physical eraseblock number the erase counter header belongs to
1154  * @ec_hdr: the erase counter header to check
1155  *
1156  * This function returns zero if the erase counter header contains valid
1157  * values, and %-EINVAL if not.
1158  */
1159 static int self_check_ec_hdr(const struct ubi_device *ubi, int pnum,
1160                              const struct ubi_ec_hdr *ec_hdr)
1161 {
1162         int err;
1163         uint32_t magic;
1164
1165         if (!ubi_dbg_chk_io(ubi))
1166                 return 0;
1167
1168         magic = be32_to_cpu(ec_hdr->magic);
1169         if (magic != UBI_EC_HDR_MAGIC) {
1170                 ubi_err(ubi, "bad magic %#08x, must be %#08x",
1171                         magic, UBI_EC_HDR_MAGIC);
1172                 goto fail;
1173         }
1174
1175         err = validate_ec_hdr(ubi, ec_hdr);
1176         if (err) {
1177                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1178                 goto fail;
1179         }
1180
1181         return 0;
1182
1183 fail:
1184         ubi_dump_ec_hdr(ec_hdr);
1185         dump_stack();
1186         return -EINVAL;
1187 }
1188
1189 /**
1190  * self_check_peb_ec_hdr - check erase counter header.
1191  * @ubi: UBI device description object
1192  * @pnum: the physical eraseblock number to check
1193  *
1194  * This function returns zero if the erase counter header is all right and and
1195  * a negative error code if not or if an error occurred.
1196  */
1197 static int self_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
1198 {
1199         int err;
1200         uint32_t crc, hdr_crc;
1201         struct ubi_ec_hdr *ec_hdr;
1202
1203         if (!ubi_dbg_chk_io(ubi))
1204                 return 0;
1205
1206         ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
1207         if (!ec_hdr)
1208                 return -ENOMEM;
1209
1210         err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
1211         if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
1212                 goto exit;
1213
1214         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
1215         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
1216         if (hdr_crc != crc) {
1217                 ubi_err(ubi, "bad CRC, calculated %#08x, read %#08x",
1218                         crc, hdr_crc);
1219                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1220                 ubi_dump_ec_hdr(ec_hdr);
1221                 dump_stack();
1222                 err = -EINVAL;
1223                 goto exit;
1224         }
1225
1226         err = self_check_ec_hdr(ubi, pnum, ec_hdr);
1227
1228 exit:
1229         kfree(ec_hdr);
1230         return err;
1231 }
1232
1233 /**
1234  * self_check_vid_hdr - check that a volume identifier header is all right.
1235  * @ubi: UBI device description object
1236  * @pnum: physical eraseblock number the volume identifier header belongs to
1237  * @vid_hdr: the volume identifier header to check
1238  *
1239  * This function returns zero if the volume identifier header is all right, and
1240  * %-EINVAL if not.
1241  */
1242 static int self_check_vid_hdr(const struct ubi_device *ubi, int pnum,
1243                               const struct ubi_vid_hdr *vid_hdr)
1244 {
1245         int err;
1246         uint32_t magic;
1247
1248         if (!ubi_dbg_chk_io(ubi))
1249                 return 0;
1250
1251         magic = be32_to_cpu(vid_hdr->magic);
1252         if (magic != UBI_VID_HDR_MAGIC) {
1253                 ubi_err(ubi, "bad VID header magic %#08x at PEB %d, must be %#08x",
1254                         magic, pnum, UBI_VID_HDR_MAGIC);
1255                 goto fail;
1256         }
1257
1258         err = validate_vid_hdr(ubi, vid_hdr);
1259         if (err) {
1260                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1261                 goto fail;
1262         }
1263
1264         return err;
1265
1266 fail:
1267         ubi_err(ubi, "self-check failed for PEB %d", pnum);
1268         ubi_dump_vid_hdr(vid_hdr);
1269         dump_stack();
1270         return -EINVAL;
1271
1272 }
1273
1274 /**
1275  * self_check_peb_vid_hdr - check volume identifier header.
1276  * @ubi: UBI device description object
1277  * @pnum: the physical eraseblock number to check
1278  *
1279  * This function returns zero if the volume identifier header is all right,
1280  * and a negative error code if not or if an error occurred.
1281  */
1282 static int self_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
1283 {
1284         int err;
1285         uint32_t crc, hdr_crc;
1286         struct ubi_vid_hdr *vid_hdr;
1287         void *p;
1288
1289         if (!ubi_dbg_chk_io(ubi))
1290                 return 0;
1291
1292         vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
1293         if (!vid_hdr)
1294                 return -ENOMEM;
1295
1296         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1297         err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1298                           ubi->vid_hdr_alsize);
1299         if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
1300                 goto exit;
1301
1302         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_EC_HDR_SIZE_CRC);
1303         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1304         if (hdr_crc != crc) {
1305                 ubi_err(ubi, "bad VID header CRC at PEB %d, calculated %#08x, read %#08x",
1306                         pnum, crc, hdr_crc);
1307                 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1308                 ubi_dump_vid_hdr(vid_hdr);
1309                 dump_stack();
1310                 err = -EINVAL;
1311                 goto exit;
1312         }
1313
1314         err = self_check_vid_hdr(ubi, pnum, vid_hdr);
1315
1316 exit:
1317         ubi_free_vid_hdr(ubi, vid_hdr);
1318         return err;
1319 }
1320
1321 /**
1322  * self_check_write - make sure write succeeded.
1323  * @ubi: UBI device description object
1324  * @buf: buffer with data which were written
1325  * @pnum: physical eraseblock number the data were written to
1326  * @offset: offset within the physical eraseblock the data were written to
1327  * @len: how many bytes were written
1328  *
1329  * This functions reads data which were recently written and compares it with
1330  * the original data buffer - the data have to match. Returns zero if the data
1331  * match and a negative error code if not or in case of failure.
1332  */
1333 static int self_check_write(struct ubi_device *ubi, const void *buf, int pnum,
1334                             int offset, int len)
1335 {
1336         int err, i;
1337         size_t read;
1338         void *buf1;
1339         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1340
1341         if (!ubi_dbg_chk_io(ubi))
1342                 return 0;
1343
1344         buf1 = __vmalloc(len, GFP_NOFS, PAGE_KERNEL);
1345         if (!buf1) {
1346                 ubi_err(ubi, "cannot allocate memory to check writes");
1347                 return 0;
1348         }
1349
1350         err = mtd_read(ubi->mtd, addr, len, &read, buf1);
1351         if (err && !mtd_is_bitflip(err))
1352                 goto out_free;
1353
1354         for (i = 0; i < len; i++) {
1355                 uint8_t c = ((uint8_t *)buf)[i];
1356                 uint8_t c1 = ((uint8_t *)buf1)[i];
1357                 int dump_len;
1358
1359                 if (c == c1)
1360                         continue;
1361
1362                 ubi_err(ubi, "self-check failed for PEB %d:%d, len %d",
1363                         pnum, offset, len);
1364                 ubi_msg(ubi, "data differ at position %d", i);
1365                 dump_len = max_t(int, 128, len - i);
1366                 ubi_msg(ubi, "hex dump of the original buffer from %d to %d",
1367                         i, i + dump_len);
1368                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1369                                buf + i, dump_len, 1);
1370                 ubi_msg(ubi, "hex dump of the read buffer from %d to %d",
1371                         i, i + dump_len);
1372                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1373                                buf1 + i, dump_len, 1);
1374                 dump_stack();
1375                 err = -EINVAL;
1376                 goto out_free;
1377         }
1378
1379         vfree(buf1);
1380         return 0;
1381
1382 out_free:
1383         vfree(buf1);
1384         return err;
1385 }
1386
1387 /**
1388  * ubi_self_check_all_ff - check that a region of flash is empty.
1389  * @ubi: UBI device description object
1390  * @pnum: the physical eraseblock number to check
1391  * @offset: the starting offset within the physical eraseblock to check
1392  * @len: the length of the region to check
1393  *
1394  * This function returns zero if only 0xFF bytes are present at offset
1395  * @offset of the physical eraseblock @pnum, and a negative error code if not
1396  * or if an error occurred.
1397  */
1398 int ubi_self_check_all_ff(struct ubi_device *ubi, int pnum, int offset, int len)
1399 {
1400         size_t read;
1401         int err;
1402         void *buf;
1403         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1404
1405         if (!ubi_dbg_chk_io(ubi))
1406                 return 0;
1407
1408         buf = __vmalloc(len, GFP_NOFS, PAGE_KERNEL);
1409         if (!buf) {
1410                 ubi_err(ubi, "cannot allocate memory to check for 0xFFs");
1411                 return 0;
1412         }
1413
1414         err = mtd_read(ubi->mtd, addr, len, &read, buf);
1415         if (err && !mtd_is_bitflip(err)) {
1416                 ubi_err(ubi, "err %d while reading %d bytes from PEB %d:%d, read %zd bytes",
1417                         err, len, pnum, offset, read);
1418                 goto error;
1419         }
1420
1421         err = ubi_check_pattern(buf, 0xFF, len);
1422         if (err == 0) {
1423                 ubi_err(ubi, "flash region at PEB %d:%d, length %d does not contain all 0xFF bytes",
1424                         pnum, offset, len);
1425                 goto fail;
1426         }
1427
1428         vfree(buf);
1429         return 0;
1430
1431 fail:
1432         ubi_err(ubi, "self-check failed for PEB %d", pnum);
1433         ubi_msg(ubi, "hex dump of the %d-%d region", offset, offset + len);
1434         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, buf, len, 1);
1435         err = -EINVAL;
1436 error:
1437         dump_stack();
1438         vfree(buf);
1439         return err;
1440 }