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 no relevant to the sub-page are 0xFF. So, basically, writing
  68  * 4x512 sub-pages is 4 times slower then writing one 2KiB NAND page. Thus, we
  69  * prefer to use sub-pages only for EV 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 "ubi.h"
  92
  93 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
  94 static int paranoid_check_not_bad(const struct ubi_device *ubi, int pnum);
  95 static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum);
  96 static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
  97                                  const struct ubi_ec_hdr *ec_hdr);
  98 static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum);
  99 static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
 100                                   const struct ubi_vid_hdr *vid_hdr);
 101 #else
 102 #define paranoid_check_not_bad(ubi, pnum) 0
 103 #define paranoid_check_peb_ec_hdr(ubi, pnum)  0
 104 #define paranoid_check_ec_hdr(ubi, pnum, ec_hdr)  0
 105 #define paranoid_check_peb_vid_hdr(ubi, pnum) 0
 106 #define paranoid_check_vid_hdr(ubi, pnum, vid_hdr) 0
 107 #endif
 108
 109 /**
 110  * ubi_io_read - read data from a physical eraseblock.
 111  * @ubi: UBI device description object
 112  * @buf: buffer where to store the read data
 113  * @pnum: physical eraseblock number to read from
 114  * @offset: offset within the physical eraseblock from where to read
 115  * @len: how many bytes to read
 116  *
 117  * This function reads data from offset @offset of physical eraseblock @pnum
 118  * and stores the read data in the @buf buffer. The following return codes are
 119  * possible:
 120  *
 121  * o %0 if all the requested data were successfully read;
 122  * o %UBI_IO_BITFLIPS if all the requested data were successfully read, but
 123  *   correctable bit-flips were detected; this is harmless but may indicate
 124  *   that this eraseblock may become bad soon (but do not have to);
 125  * o %-EBADMSG if the MTD subsystem reported about data integrity problems, for
 126  *   example it can be an ECC error in case of NAND; this most probably means
 127  *   that the data is corrupted;
 128  * o %-EIO if some I/O error occurred;
 129  * o other negative error codes in case of other errors.
 130  */
 131 int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 132                 int len)
 133 {
 134         int err, retries = 0;
 135         size_t read;
 136         loff_t addr;
 137
 138         dbg_io("read %d bytes from PEB %d:%d", len, pnum, offset);
 139
 140         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 141         ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 142         ubi_assert(len > 0);
 143
 144         err = paranoid_check_not_bad(ubi, pnum);
 145         if (err)
 146                 return err > 0 ? -EINVAL : err;
 147
 148         addr = (loff_t)pnum * ubi->peb_size + offset;
 149 retry:
 150         err = ubi->mtd->read(ubi->mtd, addr, len, &read, buf);
 151         if (err) {
 152                 if (err == -EUCLEAN) {
 153                         /*
 154                          * -EUCLEAN is reported if there was a bit-flip which
 155                          * was corrected, so this is harmless.
 156                          *
 157                          * We do not report about it here unless debugging is
 158                          * enabled. A corresponding message will be printed
 159                          * later, when it is has been scrubbed.
 160                          */
 161                         dbg_msg("fixable bit-flip detected at PEB %d", pnum);
 162                         ubi_assert(len == read);
 163                         return UBI_IO_BITFLIPS;
 164                 }
 165
 166                 if (read != len && retries++ < UBI_IO_RETRIES) {
 167                         dbg_io("error %d while reading %d bytes from PEB %d:%d,"
 168                                " read only %zd bytes, retry",
 169                                err, len, pnum, offset, read);
 170                         yield();
 171                         goto retry;
 172                 }
 173
 174                 ubi_err("error %d while reading %d bytes from PEB %d:%d, "
 175                         "read %zd bytes", err, len, pnum, offset, read);
 176                 ubi_dbg_dump_stack();
 177
 178                 /*
 179                  * The driver should never return -EBADMSG if it failed to read
 180                  * all the requested data. But some buggy drivers might do
 181                  * this, so we change it to -EIO.
 182                  */
 183                 if (read != len && err == -EBADMSG) {
 184                         ubi_assert(0);
 185                         err = -EIO;
 186                 }
 187         } else {
 188                 ubi_assert(len == read);
 189
 190                 if (ubi_dbg_is_bitflip()) {
 191                         dbg_gen("bit-flip (emulated)");
 192                         err = UBI_IO_BITFLIPS;
 193                 }
 194         }
 195
 196         return err;
 197 }
 198
 199 /**
 200  * ubi_io_write - write data to a physical eraseblock.
 201  * @ubi: UBI device description object
 202  * @buf: buffer with the data to write
 203  * @pnum: physical eraseblock number to write to
 204  * @offset: offset within the physical eraseblock where to write
 205  * @len: how many bytes to write
 206  *
 207  * This function writes @len bytes of data from buffer @buf to offset @offset
 208  * of physical eraseblock @pnum. If all the data were successfully written,
 209  * zero is returned. If an error occurred, this function returns a negative
 210  * error code. If %-EIO is returned, the physical eraseblock most probably went
 211  * bad.
 212  *
 213  * Note, in case of an error, it is possible that something was still written
 214  * to the flash media, but may be some garbage.
 215  */
 216 int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
 217                  int len)
 218 {
 219         int err;
 220         size_t written;
 221         loff_t addr;
 222
 223         dbg_io("write %d bytes to PEB %d:%d", len, pnum, offset);
 224
 225         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 226         ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 227         ubi_assert(offset % ubi->hdrs_min_io_size == 0);
 228         ubi_assert(len > 0 && len % ubi->hdrs_min_io_size == 0);
 229
 230         if (ubi->ro_mode) {
 231                 ubi_err("read-only mode");
 232                 return -EROFS;
 233         }
 234
 235         /* The below has to be compiled out if paranoid checks are disabled */
 236
 237         err = paranoid_check_not_bad(ubi, pnum);
 238         if (err)
 239                 return err > 0 ? -EINVAL : err;
 240
 241         /* The area we are writing to has to contain all 0xFF bytes */
 242         err = ubi_dbg_check_all_ff(ubi, pnum, offset, len);
 243         if (err)
 244                 return err > 0 ? -EINVAL : err;
 245
 246         if (offset >= ubi->leb_start) {
 247                 /*
 248                  * We write to the data area of the physical eraseblock. Make
 249                  * sure it has valid EC and VID headers.
 250                  */
 251                 err = paranoid_check_peb_ec_hdr(ubi, pnum);
 252                 if (err)
 253                         return err > 0 ? -EINVAL : err;
 254                 err = paranoid_check_peb_vid_hdr(ubi, pnum);
 255                 if (err)
 256                         return err > 0 ? -EINVAL : err;
 257         }
 258
 259         if (ubi_dbg_is_write_failure()) {
 260                 dbg_err("cannot write %d bytes to PEB %d:%d "
 261                         "(emulated)", len, pnum, offset);
 262                 ubi_dbg_dump_stack();
 263                 return -EIO;
 264         }
 265
 266         addr = (loff_t)pnum * ubi->peb_size + offset;
 267         err = ubi->mtd->write(ubi->mtd, addr, len, &written, buf);
 268         if (err) {
 269                 ubi_err("error %d while writing %d bytes to PEB %d:%d, written "
 270                         "%zd bytes", err, len, pnum, offset, written);
 271                 ubi_dbg_dump_stack();
 272                 ubi_dbg_dump_flash(ubi, pnum, offset, len);
 273         } else
 274                 ubi_assert(written == len);
 275
 276         return err;
 277 }
 278
 279 /**
 280  * erase_callback - MTD erasure call-back.
 281  * @ei: MTD erase information object.
 282  *
 283  * Note, even though MTD erase interface is asynchronous, all the current
 284  * implementations are synchronous anyway.
 285  */
 286 static void erase_callback(struct erase_info *ei)
 287 {
 288         wake_up_interruptible((wait_queue_head_t *)ei->priv);
 289 }
 290
 291 /**
 292  * do_sync_erase - synchronously erase a physical eraseblock.
 293  * @ubi: UBI device description object
 294  * @pnum: the physical eraseblock number to erase
 295  *
 296  * This function synchronously erases physical eraseblock @pnum and returns
 297  * zero in case of success and a negative error code in case of failure. If
 298  * %-EIO is returned, the physical eraseblock most probably went bad.
 299  */
 300 static int do_sync_erase(struct ubi_device *ubi, int pnum)
 301 {
 302         int err, retries = 0;
 303         struct erase_info ei;
 304         wait_queue_head_t wq;
 305
 306         dbg_io("erase PEB %d", pnum);
 307
 308 retry:
 309         init_waitqueue_head(&wq);
 310         memset(&ei, 0, sizeof(struct erase_info));
 311
 312         ei.mtd      = ubi->mtd;
 313         ei.addr     = (loff_t)pnum * ubi->peb_size;
 314         ei.len      = ubi->peb_size;
 315         ei.callback = erase_callback;
 316         ei.priv     = (unsigned long)&wq;
 317
 318         err = ubi->mtd->erase(ubi->mtd, &ei);
 319         if (err) {
 320                 if (retries++ < UBI_IO_RETRIES) {
 321                         dbg_io("error %d while erasing PEB %d, retry",
 322                                err, pnum);
 323                         yield();
 324                         goto retry;
 325                 }
 326                 ubi_err("cannot erase PEB %d, error %d", pnum, err);
 327                 ubi_dbg_dump_stack();
 328                 return err;
 329         }
 330
 331         err = wait_event_interruptible(wq, ei.state == MTD_ERASE_DONE ||
 332                                            ei.state == MTD_ERASE_FAILED);
 333         if (err) {
 334                 ubi_err("interrupted PEB %d erasure", pnum);
 335                 return -EINTR;
 336         }
 337
 338         if (ei.state == MTD_ERASE_FAILED) {
 339                 if (retries++ < UBI_IO_RETRIES) {
 340                         dbg_io("error while erasing PEB %d, retry", pnum);
 341                         yield();
 342                         goto retry;
 343                 }
 344                 ubi_err("cannot erase PEB %d", pnum);
 345                 ubi_dbg_dump_stack();
 346                 return -EIO;
 347         }
 348
 349         err = ubi_dbg_check_all_ff(ubi, pnum, 0, ubi->peb_size);
 350         if (err)
 351                 return err > 0 ? -EINVAL : err;
 352
 353         if (ubi_dbg_is_erase_failure() && !err) {
 354                 dbg_err("cannot erase PEB %d (emulated)", pnum);
 355                 return -EIO;
 356         }
 357
 358         return 0;
 359 }
 360
 361 /**
 362  * check_pattern - check if buffer contains only a certain byte pattern.
 363  * @buf: buffer to check
 364  * @patt: the pattern to check
 365  * @size: buffer size in bytes
 366  *
 367  * This function returns %1 in there are only @patt bytes in @buf, and %0 if
 368  * something else was also found.
 369  */
 370 static int check_pattern(const void *buf, uint8_t patt, int size)
 371 {
 372         int i;
 373
 374         for (i = 0; i < size; i++)
 375                 if (((const uint8_t *)buf)[i] != patt)
 376                         return 0;
 377         return 1;
 378 }
 379
 380 /* Patterns to write to a physical eraseblock when torturing it */
 381 static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
 382
 383 /**
 384  * torture_peb - test a supposedly bad physical eraseblock.
 385  * @ubi: UBI device description object
 386  * @pnum: the physical eraseblock number to test
 387  *
 388  * This function returns %-EIO if the physical eraseblock did not pass the
 389  * test, a positive number of erase operations done if the test was
 390  * successfully passed, and other negative error codes in case of other errors.
 391  */
 392 static int torture_peb(struct ubi_device *ubi, int pnum)
 393 {
 394         int err, i, patt_count;
 395
 396         ubi_msg("run torture test for PEB %d", pnum);
 397         patt_count = ARRAY_SIZE(patterns);
 398         ubi_assert(patt_count > 0);
 399
 400         mutex_lock(&ubi->buf_mutex);
 401         for (i = 0; i < patt_count; i++) {
 402                 err = do_sync_erase(ubi, pnum);
 403                 if (err)
 404                         goto out;
 405
 406                 /* Make sure the PEB contains only 0xFF bytes */
 407                 err = ubi_io_read(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 408                 if (err)
 409                         goto out;
 410
 411                 err = check_pattern(ubi->peb_buf1, 0xFF, ubi->peb_size);
 412                 if (err == 0) {
 413                         ubi_err("erased PEB %d, but a non-0xFF byte found",
 414                                 pnum);
 415                         err = -EIO;
 416                         goto out;
 417                 }
 418
 419                 /* Write a pattern and check it */
 420                 memset(ubi->peb_buf1, patterns[i], ubi->peb_size);
 421                 err = ubi_io_write(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 422                 if (err)
 423                         goto out;
 424
 425                 memset(ubi->peb_buf1, ~patterns[i], ubi->peb_size);
 426                 err = ubi_io_read(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 427                 if (err)
 428                         goto out;
 429
 430                 err = check_pattern(ubi->peb_buf1, patterns[i], ubi->peb_size);
 431                 if (err == 0) {
 432                         ubi_err("pattern %x checking failed for PEB %d",
 433                                 patterns[i], pnum);
 434                         err = -EIO;
 435                         goto out;
 436                 }
 437         }
 438
 439         err = patt_count;
 440         ubi_msg("PEB %d passed torture test, do not mark it a bad", pnum);
 441
 442 out:
 443         mutex_unlock(&ubi->buf_mutex);
 444         if (err == UBI_IO_BITFLIPS || err == -EBADMSG) {
 445                 /*
 446                  * If a bit-flip or data integrity error was detected, the test
 447                  * has not passed because it happened on a freshly erased
 448                  * physical eraseblock which means something is wrong with it.
 449                  */
 450                 ubi_err("read problems on freshly erased PEB %d, must be bad",
 451                         pnum);
 452                 err = -EIO;
 453         }
 454         return err;
 455 }
 456
 457 /**
 458  * nor_erase_prepare - prepare a NOR flash PEB for erasure.
 459  * @ubi: UBI device description object
 460  * @pnum: physical eraseblock number to prepare
 461  *
 462  * NOR flash, or at least some of them, have peculiar embedded PEB erasure
 463  * algorithm: the PEB is first filled with zeroes, then it is erased. And
 464  * filling with zeroes starts from the end of the PEB. This was observed with
 465  * Spansion S29GL512N NOR flash.
 466  *
 467  * This means that in case of a power cut we may end up with intact data at the
 468  * beginning of the PEB, and all zeroes at the end of PEB. In other words, the
 469  * EC and VID headers are OK, but a large chunk of data at the end of PEB is
 470  * zeroed. This makes UBI mistakenly treat this PEB as used and associate it
 471  * with an LEB, which leads to subsequent failures (e.g., UBIFS fails).
 472  *
 473  * This function is called before erasing NOR PEBs and it zeroes out EC and VID
 474  * magic numbers in order to invalidate them and prevent the failures. Returns
 475  * zero in case of success and a negative error code in case of failure.
 476  */
 477 static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 478 {
 479         int err;
 480         size_t written;
 481         loff_t addr;
 482         uint32_t data = 0;
 483
 484         addr = (loff_t)pnum * ubi->peb_size + ubi->vid_hdr_aloffset;
 485         err = ubi->mtd->write(ubi->mtd, addr, 4, &written, (void *)&data);
 486         if (err) {
 487                 ubi_err("error %d while writing 4 bytes to PEB %d:%d, written "
 488                         "%zd bytes", err, pnum, ubi->vid_hdr_aloffset, written);
 489                 ubi_dbg_dump_stack();
 490                 return err;
 491         }
 492
 493         addr -= ubi->vid_hdr_aloffset;
 494         err = ubi->mtd->write(ubi->mtd, addr, 4, &written, (void *)&data);
 495         if (err) {
 496                 ubi_err("error %d while writing 4 bytes to PEB %d:%d, written "
 497                         "%zd bytes", err, pnum, 0, written);
 498                 ubi_dbg_dump_stack();
 499                 return err;
 500         }
 501
 502         return 0;
 503 }
 504
 505 /**
 506  * ubi_io_sync_erase - synchronously erase a physical eraseblock.
 507  * @ubi: UBI device description object
 508  * @pnum: physical eraseblock number to erase
 509  * @torture: if this physical eraseblock has to be tortured
 510  *
 511  * This function synchronously erases physical eraseblock @pnum. If @torture
 512  * flag is not zero, the physical eraseblock is checked by means of writing
 513  * different patterns to it and reading them back. If the torturing is enabled,
 514  * the physical eraseblock is erased more than once.
 515  *
 516  * This function returns the number of erasures made in case of success, %-EIO
 517  * if the erasure failed or the torturing test failed, and other negative error
 518  * codes in case of other errors. Note, %-EIO means that the physical
 519  * eraseblock is bad.
 520  */
 521 int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
 522 {
 523         int err, ret = 0;
 524
 525         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 526
 527         err = paranoid_check_not_bad(ubi, pnum);
 528         if (err != 0)
 529                 return err > 0 ? -EINVAL : err;
 530
 531         if (ubi->ro_mode) {
 532                 ubi_err("read-only mode");
 533                 return -EROFS;
 534         }
 535
 536         if (ubi->nor_flash) {
 537                 err = nor_erase_prepare(ubi, pnum);
 538                 if (err)
 539                         return err;
 540         }
 541
 542         if (torture) {
 543                 ret = torture_peb(ubi, pnum);
 544                 if (ret < 0)
 545                         return ret;
 546         }
 547
 548         err = do_sync_erase(ubi, pnum);
 549         if (err)
 550                 return err;
 551
 552         return ret + 1;
 553 }
 554
 555 /**
 556  * ubi_io_is_bad - check if a physical eraseblock is bad.
 557  * @ubi: UBI device description object
 558  * @pnum: the physical eraseblock number to check
 559  *
 560  * This function returns a positive number if the physical eraseblock is bad,
 561  * zero if not, and a negative error code if an error occurred.
 562  */
 563 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum)
 564 {
 565         struct mtd_info *mtd = ubi->mtd;
 566
 567         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 568
 569         if (ubi->bad_allowed) {
 570                 int ret;
 571
 572                 ret = mtd->block_isbad(mtd, (loff_t)pnum * ubi->peb_size);
 573                 if (ret < 0)
 574                         ubi_err("error %d while checking if PEB %d is bad",
 575                                 ret, pnum);
 576                 else if (ret)
 577                         dbg_io("PEB %d is bad", pnum);
 578                 return ret;
 579         }
 580
 581         return 0;
 582 }
 583
 584 /**
 585  * ubi_io_mark_bad - mark a physical eraseblock as bad.
 586  * @ubi: UBI device description object
 587  * @pnum: the physical eraseblock number to mark
 588  *
 589  * This function returns zero in case of success and a negative error code in
 590  * case of failure.
 591  */
 592 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
 593 {
 594         int err;
 595         struct mtd_info *mtd = ubi->mtd;
 596
 597         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 598
 599         if (ubi->ro_mode) {
 600                 ubi_err("read-only mode");
 601                 return -EROFS;
 602         }
 603
 604         if (!ubi->bad_allowed)
 605                 return 0;
 606
 607         err = mtd->block_markbad(mtd, (loff_t)pnum * ubi->peb_size);
 608         if (err)
 609                 ubi_err("cannot mark PEB %d bad, error %d", pnum, err);
 610         return err;
 611 }
 612
 613 /**
 614  * validate_ec_hdr - validate an erase counter header.
 615  * @ubi: UBI device description object
 616  * @ec_hdr: the erase counter header to check
 617  *
 618  * This function returns zero if the erase counter header is OK, and %1 if
 619  * not.
 620  */
 621 static int validate_ec_hdr(const struct ubi_device *ubi,
 622                            const struct ubi_ec_hdr *ec_hdr)
 623 {
 624         long long ec;
 625         int vid_hdr_offset, leb_start;
 626
 627         ec = be64_to_cpu(ec_hdr->ec);
 628         vid_hdr_offset = be32_to_cpu(ec_hdr->vid_hdr_offset);
 629         leb_start = be32_to_cpu(ec_hdr->data_offset);
 630
 631         if (ec_hdr->version != UBI_VERSION) {
 632                 ubi_err("node with incompatible UBI version found: "
 633                         "this UBI version is %d, image version is %d",
 634                         UBI_VERSION, (int)ec_hdr->version);
 635                 goto bad;
 636         }
 637
 638         if (vid_hdr_offset != ubi->vid_hdr_offset) {
 639                 ubi_err("bad VID header offset %d, expected %d",
 640                         vid_hdr_offset, ubi->vid_hdr_offset);
 641                 goto bad;
 642         }
 643
 644         if (leb_start != ubi->leb_start) {
 645                 ubi_err("bad data offset %d, expected %d",
 646                         leb_start, ubi->leb_start);
 647                 goto bad;
 648         }
 649
 650         if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
 651                 ubi_err("bad erase counter %lld", ec);
 652                 goto bad;
 653         }
 654
 655         return 0;
 656
 657 bad:
 658         ubi_err("bad EC header");
 659         ubi_dbg_dump_ec_hdr(ec_hdr);
 660         ubi_dbg_dump_stack();
 661         return 1;
 662 }
 663
 664 /**
 665  * ubi_io_read_ec_hdr - read and check an erase counter header.
 666  * @ubi: UBI device description object
 667  * @pnum: physical eraseblock to read from
 668  * @ec_hdr: a &struct ubi_ec_hdr object where to store the read erase counter
 669  * header
 670  * @verbose: be verbose if the header is corrupted or was not found
 671  *
 672  * This function reads erase counter header from physical eraseblock @pnum and
 673  * stores it in @ec_hdr. This function also checks CRC checksum of the read
 674  * erase counter header. The following codes may be returned:
 675  *
 676  * o %0 if the CRC checksum is correct and the header was successfully read;
 677  * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 678  *   and corrected by the flash driver; this is harmless but may indicate that
 679  *   this eraseblock may become bad soon (but may be not);
 680  * o %UBI_IO_BAD_EC_HDR if the erase counter header is corrupted (a CRC error);
 681  * o %UBI_IO_PEB_EMPTY if the physical eraseblock is empty;
 682  * o a negative error code in case of failure.
 683  */
 684 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 685                        struct ubi_ec_hdr *ec_hdr, int verbose)
 686 {
 687         int err, read_err = 0;
 688         uint32_t crc, magic, hdr_crc;
 689
 690         dbg_io("read EC header from PEB %d", pnum);
 691         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 692
 693         err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
 694         if (err) {
 695                 if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
 696                         return err;
 697
 698                 /*
 699                  * We read all the data, but either a correctable bit-flip
 700                  * occurred, or MTD reported about some data integrity error,
 701                  * like an ECC error in case of NAND. The former is harmless,
 702                  * the later may mean that the read data is corrupted. But we
 703                  * have a CRC check-sum and we will detect this. If the EC
 704                  * header is still OK, we just report this as there was a
 705                  * bit-flip.
 706                  */
 707                 read_err = err;
 708         }
 709
 710         magic = be32_to_cpu(ec_hdr->magic);
 711         if (magic != UBI_EC_HDR_MAGIC) {
 712                 /*
 713                  * The magic field is wrong. Let's check if we have read all
 714                  * 0xFF. If yes, this physical eraseblock is assumed to be
 715                  * empty.
 716                  *
 717                  * But if there was a read error, we do not test it for all
 718                  * 0xFFs. Even if it does contain all 0xFFs, this error
 719                  * indicates that something is still wrong with this physical
 720                  * eraseblock and we anyway cannot treat it as empty.
 721                  */
 722                 if (read_err != -EBADMSG &&
 723                     check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
 724                         /* The physical eraseblock is supposedly empty */
 725                         if (verbose)
 726                                 ubi_warn("no EC header found at PEB %d, "
 727                                          "only 0xFF bytes", pnum);
 728                         else if (UBI_IO_DEBUG)
 729                                 dbg_msg("no EC header found at PEB %d, "
 730                                         "only 0xFF bytes", pnum);
 731                         return UBI_IO_PEB_EMPTY;
 732                 }
 733
 734                 /*
 735                  * This is not a valid erase counter header, and these are not
 736                  * 0xFF bytes. Report that the header is corrupted.
 737                  */
 738                 if (verbose) {
 739                         ubi_warn("bad magic number at PEB %d: %08x instead of "
 740                                  "%08x", pnum, magic, UBI_EC_HDR_MAGIC);
 741                         ubi_dbg_dump_ec_hdr(ec_hdr);
 742                 } else if (UBI_IO_DEBUG)
 743                         dbg_msg("bad magic number at PEB %d: %08x instead of "
 744                                 "%08x", pnum, magic, UBI_EC_HDR_MAGIC);
 745                 return UBI_IO_BAD_EC_HDR;
 746         }
 747
 748         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 749         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
 750
 751         if (hdr_crc != crc) {
 752                 if (verbose) {
 753                         ubi_warn("bad EC header CRC at PEB %d, calculated "
 754                                  "%#08x, read %#08x", pnum, crc, hdr_crc);
 755                         ubi_dbg_dump_ec_hdr(ec_hdr);
 756                 } else if (UBI_IO_DEBUG)
 757                         dbg_msg("bad EC header CRC at PEB %d, calculated "
 758                                 "%#08x, read %#08x", pnum, crc, hdr_crc);
 759                 return UBI_IO_BAD_EC_HDR;
 760         }
 761
 762         /* And of course validate what has just been read from the media */
 763         err = validate_ec_hdr(ubi, ec_hdr);
 764         if (err) {
 765                 ubi_err("validation failed for PEB %d", pnum);
 766                 return -EINVAL;
 767         }
 768
 769         return read_err ? UBI_IO_BITFLIPS : 0;
 770 }
 771
 772 /**
 773  * ubi_io_write_ec_hdr - write an erase counter header.
 774  * @ubi: UBI device description object
 775  * @pnum: physical eraseblock to write to
 776  * @ec_hdr: the erase counter header to write
 777  *
 778  * This function writes erase counter header described by @ec_hdr to physical
 779  * eraseblock @pnum. It also fills most fields of @ec_hdr before writing, so
 780  * the caller do not have to fill them. Callers must only fill the @ec_hdr->ec
 781  * field.
 782  *
 783  * This function returns zero in case of success and a negative error code in
 784  * case of failure. If %-EIO is returned, the physical eraseblock most probably
 785  * went bad.
 786  */
 787 int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 788                         struct ubi_ec_hdr *ec_hdr)
 789 {
 790         int err;
 791         uint32_t crc;
 792
 793         dbg_io("write EC header to PEB %d", pnum);
 794         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 795
 796         ec_hdr->magic = cpu_to_be32(UBI_EC_HDR_MAGIC);
 797         ec_hdr->version = UBI_VERSION;
 798         ec_hdr->vid_hdr_offset = cpu_to_be32(ubi->vid_hdr_offset);
 799         ec_hdr->data_offset = cpu_to_be32(ubi->leb_start);
 800         ec_hdr->image_seq = cpu_to_be32(ubi->image_seq);
 801         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 802         ec_hdr->hdr_crc = cpu_to_be32(crc);
 803
 804         err = paranoid_check_ec_hdr(ubi, pnum, ec_hdr);
 805         if (err)
 806                 return -EINVAL;
 807
 808         err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
 809         return err;
 810 }
 811
 812 /**
 813  * validate_vid_hdr - validate a volume identifier header.
 814  * @ubi: UBI device description object
 815  * @vid_hdr: the volume identifier header to check
 816  *
 817  * This function checks that data stored in the volume identifier header
 818  * @vid_hdr. Returns zero if the VID header is OK and %1 if not.
 819  */
 820 static int validate_vid_hdr(const struct ubi_device *ubi,
 821                             const struct ubi_vid_hdr *vid_hdr)
 822 {
 823         int vol_type = vid_hdr->vol_type;
 824         int copy_flag = vid_hdr->copy_flag;
 825         int vol_id = be32_to_cpu(vid_hdr->vol_id);
 826         int lnum = be32_to_cpu(vid_hdr->lnum);
 827         int compat = vid_hdr->compat;
 828         int data_size = be32_to_cpu(vid_hdr->data_size);
 829         int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
 830         int data_pad = be32_to_cpu(vid_hdr->data_pad);
 831         int data_crc = be32_to_cpu(vid_hdr->data_crc);
 832         int usable_leb_size = ubi->leb_size - data_pad;
 833
 834         if (copy_flag != 0 && copy_flag != 1) {
 835                 dbg_err("bad copy_flag");
 836                 goto bad;
 837         }
 838
 839         if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
 840             data_pad < 0) {
 841                 dbg_err("negative values");
 842                 goto bad;
 843         }
 844
 845         if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
 846                 dbg_err("bad vol_id");
 847                 goto bad;
 848         }
 849
 850         if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
 851                 dbg_err("bad compat");
 852                 goto bad;
 853         }
 854
 855         if (vol_id >= UBI_INTERNAL_VOL_START && compat != UBI_COMPAT_DELETE &&
 856             compat != UBI_COMPAT_RO && compat != UBI_COMPAT_PRESERVE &&
 857             compat != UBI_COMPAT_REJECT) {
 858                 dbg_err("bad compat");
 859                 goto bad;
 860         }
 861
 862         if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
 863                 dbg_err("bad vol_type");
 864                 goto bad;
 865         }
 866
 867         if (data_pad >= ubi->leb_size / 2) {
 868                 dbg_err("bad data_pad");
 869                 goto bad;
 870         }
 871
 872         if (vol_type == UBI_VID_STATIC) {
 873                 /*
 874                  * Although from high-level point of view static volumes may
 875                  * contain zero bytes of data, but no VID headers can contain
 876                  * zero at these fields, because they empty volumes do not have
 877                  * mapped logical eraseblocks.
 878                  */
 879                 if (used_ebs == 0) {
 880                         dbg_err("zero used_ebs");
 881                         goto bad;
 882                 }
 883                 if (data_size == 0) {
 884                         dbg_err("zero data_size");
 885                         goto bad;
 886                 }
 887                 if (lnum < used_ebs - 1) {
 888                         if (data_size != usable_leb_size) {
 889                                 dbg_err("bad data_size");
 890                                 goto bad;
 891                         }
 892                 } else if (lnum == used_ebs - 1) {
 893                         if (data_size == 0) {
 894                                 dbg_err("bad data_size at last LEB");
 895                                 goto bad;
 896                         }
 897                 } else {
 898                         dbg_err("too high lnum");
 899                         goto bad;
 900                 }
 901         } else {
 902                 if (copy_flag == 0) {
 903                         if (data_crc != 0) {
 904                                 dbg_err("non-zero data CRC");
 905                                 goto bad;
 906                         }
 907                         if (data_size != 0) {
 908                                 dbg_err("non-zero data_size");
 909                                 goto bad;
 910                         }
 911                 } else {
 912                         if (data_size == 0) {
 913                                 dbg_err("zero data_size of copy");
 914                                 goto bad;
 915                         }
 916                 }
 917                 if (used_ebs != 0) {
 918                         dbg_err("bad used_ebs");
 919                         goto bad;
 920                 }
 921         }
 922
 923         return 0;
 924
 925 bad:
 926         ubi_err("bad VID header");
 927         ubi_dbg_dump_vid_hdr(vid_hdr);
 928         ubi_dbg_dump_stack();
 929         return 1;
 930 }
 931
 932 /**
 933  * ubi_io_read_vid_hdr - read and check a volume identifier header.
 934  * @ubi: UBI device description object
 935  * @pnum: physical eraseblock number to read from
 936  * @vid_hdr: &struct ubi_vid_hdr object where to store the read volume
 937  * identifier header
 938  * @verbose: be verbose if the header is corrupted or wasn't found
 939  *
 940  * This function reads the volume identifier header from physical eraseblock
 941  * @pnum and stores it in @vid_hdr. It also checks CRC checksum of the read
 942  * volume identifier header. The following codes may be returned:
 943  *
 944  * o %0 if the CRC checksum is correct and the header was successfully read;
 945  * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 946  *   and corrected by the flash driver; this is harmless but may indicate that
 947  *   this eraseblock may become bad soon;
 948  * o %UBI_IO_BAD_VID_HDR if the volume identifier header is corrupted (a CRC
 949  *   error detected);
 950  * o %UBI_IO_PEB_FREE if the physical eraseblock is free (i.e., there is no VID
 951  *   header there);
 952  * o a negative error code in case of failure.
 953  */
 954 int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 955                         struct ubi_vid_hdr *vid_hdr, int verbose)
 956 {
 957         int err, read_err = 0;
 958         uint32_t crc, magic, hdr_crc;
 959         void *p;
 960
 961         dbg_io("read VID header from PEB %d", pnum);
 962         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 963
 964         p = (char *)vid_hdr - ubi->vid_hdr_shift;
 965         err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
 966                           ubi->vid_hdr_alsize);
 967         if (err) {
 968                 if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
 969                         return err;
 970
 971                 /*
 972                  * We read all the data, but either a correctable bit-flip
 973                  * occurred, or MTD reported about some data integrity error,
 974                  * like an ECC error in case of NAND. The former is harmless,
 975                  * the later may mean the read data is corrupted. But we have a
 976                  * CRC check-sum and we will identify this. If the VID header is
 977                  * still OK, we just report this as there was a bit-flip.
 978                  */
 979                 read_err = err;
 980         }
 981
 982         magic = be32_to_cpu(vid_hdr->magic);
 983         if (magic != UBI_VID_HDR_MAGIC) {
 984                 /*
 985                  * If we have read all 0xFF bytes, the VID header probably does
 986                  * not exist and the physical eraseblock is assumed to be free.
 987                  *
 988                  * But if there was a read error, we do not test the data for
 989                  * 0xFFs. Even if it does contain all 0xFFs, this error
 990                  * indicates that something is still wrong with this physical
 991                  * eraseblock and it cannot be regarded as free.
 992                  */
 993                 if (read_err != -EBADMSG &&
 994                     check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
 995                         /* The physical eraseblock is supposedly free */
 996                         if (verbose)
 997                                 ubi_warn("no VID header found at PEB %d, "
 998                                          "only 0xFF bytes", pnum);
 999                         else if (UBI_IO_DEBUG)
1000                                 dbg_msg("no VID header found at PEB %d, "
1001                                         "only 0xFF bytes", pnum);
1002                         return UBI_IO_PEB_FREE;
1003                 }
1004
1005                 /*
1006                  * This is not a valid VID header, and these are not 0xFF
1007                  * bytes. Report that the header is corrupted.
1008                  */
1009                 if (verbose) {
1010                         ubi_warn("bad magic number at PEB %d: %08x instead of "
1011                                  "%08x", pnum, magic, UBI_VID_HDR_MAGIC);
1012                         ubi_dbg_dump_vid_hdr(vid_hdr);
1013                 } else if (UBI_IO_DEBUG)
1014                         dbg_msg("bad magic number at PEB %d: %08x instead of "
1015                                 "%08x", pnum, magic, UBI_VID_HDR_MAGIC);
1016                 return UBI_IO_BAD_VID_HDR;
1017         }
1018
1019         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1020         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1021
1022         if (hdr_crc != crc) {
1023                 if (verbose) {
1024                         ubi_warn("bad CRC at PEB %d, calculated %#08x, "
1025                                  "read %#08x", pnum, crc, hdr_crc);
1026                         ubi_dbg_dump_vid_hdr(vid_hdr);
1027                 } else if (UBI_IO_DEBUG)
1028                         dbg_msg("bad CRC at PEB %d, calculated %#08x, "
1029                                 "read %#08x", pnum, crc, hdr_crc);
1030                 return UBI_IO_BAD_VID_HDR;
1031         }
1032
1033         /* Validate the VID header that we have just read */
1034         err = validate_vid_hdr(ubi, vid_hdr);
1035         if (err) {
1036                 ubi_err("validation failed for PEB %d", pnum);
1037                 return -EINVAL;
1038         }
1039
1040         return read_err ? UBI_IO_BITFLIPS : 0;
1041 }
1042
1043 /**
1044  * ubi_io_write_vid_hdr - write a volume identifier header.
1045  * @ubi: UBI device description object
1046  * @pnum: the physical eraseblock number to write to
1047  * @vid_hdr: the volume identifier header to write
1048  *
1049  * This function writes the volume identifier header described by @vid_hdr to
1050  * physical eraseblock @pnum. This function automatically fills the
1051  * @vid_hdr->magic and the @vid_hdr->version fields, as well as calculates
1052  * header CRC checksum and stores it at vid_hdr->hdr_crc.
1053  *
1054  * This function returns zero in case of success and a negative error code in
1055  * case of failure. If %-EIO is returned, the physical eraseblock probably went
1056  * bad.
1057  */
1058 int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
1059                          struct ubi_vid_hdr *vid_hdr)
1060 {
1061         int err;
1062         uint32_t crc;
1063         void *p;
1064
1065         dbg_io("write VID header to PEB %d", pnum);
1066         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
1067
1068         err = paranoid_check_peb_ec_hdr(ubi, pnum);
1069         if (err)
1070                 return err > 0 ? -EINVAL : err;
1071
1072         vid_hdr->magic = cpu_to_be32(UBI_VID_HDR_MAGIC);
1073         vid_hdr->version = UBI_VERSION;
1074         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1075         vid_hdr->hdr_crc = cpu_to_be32(crc);
1076
1077         err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
1078         if (err)
1079                 return -EINVAL;
1080
1081         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1082         err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
1083                            ubi->vid_hdr_alsize);
1084         return err;
1085 }
1086
1087 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
1088
1089 /**
1090  * paranoid_check_not_bad - ensure that a physical eraseblock is not bad.
1091  * @ubi: UBI device description object
1092  * @pnum: physical eraseblock number to check
1093  *
1094  * This function returns zero if the physical eraseblock is good, a positive
1095  * number if it is bad and a negative error code if an error occurred.
1096  */
1097 static int paranoid_check_not_bad(const struct ubi_device *ubi, int pnum)
1098 {
1099         int err;
1100
1101         err = ubi_io_is_bad(ubi, pnum);
1102         if (!err)
1103                 return err;
1104
1105         ubi_err("paranoid check failed for PEB %d", pnum);
1106         ubi_dbg_dump_stack();
1107         return err;
1108 }
1109
1110 /**
1111  * paranoid_check_ec_hdr - check if an erase counter header is all right.
1112  * @ubi: UBI device description object
1113  * @pnum: physical eraseblock number the erase counter header belongs to
1114  * @ec_hdr: the erase counter header to check
1115  *
1116  * This function returns zero if the erase counter header contains valid
1117  * values, and %1 if not.
1118  */
1119 static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
1120                                  const struct ubi_ec_hdr *ec_hdr)
1121 {
1122         int err;
1123         uint32_t magic;
1124
1125         magic = be32_to_cpu(ec_hdr->magic);
1126         if (magic != UBI_EC_HDR_MAGIC) {
1127                 ubi_err("bad magic %#08x, must be %#08x",
1128                         magic, UBI_EC_HDR_MAGIC);
1129                 goto fail;
1130         }
1131
1132         err = validate_ec_hdr(ubi, ec_hdr);
1133         if (err) {
1134                 ubi_err("paranoid check failed for PEB %d", pnum);
1135                 goto fail;
1136         }
1137
1138         return 0;
1139
1140 fail:
1141         ubi_dbg_dump_ec_hdr(ec_hdr);
1142         ubi_dbg_dump_stack();
1143         return 1;
1144 }
1145
1146 /**
1147  * paranoid_check_peb_ec_hdr - check erase counter header.
1148  * @ubi: UBI device description object
1149  * @pnum: the physical eraseblock number to check
1150  *
1151  * This function returns zero if the erase counter header is all right, %1 if
1152  * not, and a negative error code if an error occurred.
1153  */
1154 static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
1155 {
1156         int err;
1157         uint32_t crc, hdr_crc;
1158         struct ubi_ec_hdr *ec_hdr;
1159
1160         ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
1161         if (!ec_hdr)
1162                 return -ENOMEM;
1163
1164         err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
1165         if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
1166                 goto exit;
1167
1168         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
1169         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
1170         if (hdr_crc != crc) {
1171                 ubi_err("bad CRC, calculated %#08x, read %#08x", crc, hdr_crc);
1172                 ubi_err("paranoid check failed for PEB %d", pnum);
1173                 ubi_dbg_dump_ec_hdr(ec_hdr);
1174                 ubi_dbg_dump_stack();
1175                 err = 1;
1176                 goto exit;
1177         }
1178
1179         err = paranoid_check_ec_hdr(ubi, pnum, ec_hdr);
1180
1181 exit:
1182         kfree(ec_hdr);
1183         return err;
1184 }
1185
1186 /**
1187  * paranoid_check_vid_hdr - check that a volume identifier header is all right.
1188  * @ubi: UBI device description object
1189  * @pnum: physical eraseblock number the volume identifier header belongs to
1190  * @vid_hdr: the volume identifier header to check
1191  *
1192  * This function returns zero if the volume identifier header is all right, and
1193  * %1 if not.
1194  */
1195 static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
1196                                   const struct ubi_vid_hdr *vid_hdr)
1197 {
1198         int err;
1199         uint32_t magic;
1200
1201         magic = be32_to_cpu(vid_hdr->magic);
1202         if (magic != UBI_VID_HDR_MAGIC) {
1203                 ubi_err("bad VID header magic %#08x at PEB %d, must be %#08x",
1204                         magic, pnum, UBI_VID_HDR_MAGIC);
1205                 goto fail;
1206         }
1207
1208         err = validate_vid_hdr(ubi, vid_hdr);
1209         if (err) {
1210                 ubi_err("paranoid check failed for PEB %d", pnum);
1211                 goto fail;
1212         }
1213
1214         return err;
1215
1216 fail:
1217         ubi_err("paranoid check failed for PEB %d", pnum);
1218         ubi_dbg_dump_vid_hdr(vid_hdr);
1219         ubi_dbg_dump_stack();
1220         return 1;
1221
1222 }
1223
1224 /**
1225  * paranoid_check_peb_vid_hdr - check volume identifier header.
1226  * @ubi: UBI device description object
1227  * @pnum: the physical eraseblock number to check
1228  *
1229  * This function returns zero if the volume identifier header is all right,
1230  * %1 if not, and a negative error code if an error occurred.
1231  */
1232 static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
1233 {
1234         int err;
1235         uint32_t crc, hdr_crc;
1236         struct ubi_vid_hdr *vid_hdr;
1237         void *p;
1238
1239         vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
1240         if (!vid_hdr)
1241                 return -ENOMEM;
1242
1243         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1244         err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1245                           ubi->vid_hdr_alsize);
1246         if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
1247                 goto exit;
1248
1249         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_EC_HDR_SIZE_CRC);
1250         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1251         if (hdr_crc != crc) {
1252                 ubi_err("bad VID header CRC at PEB %d, calculated %#08x, "
1253                         "read %#08x", pnum, crc, hdr_crc);
1254                 ubi_err("paranoid check failed for PEB %d", pnum);
1255                 ubi_dbg_dump_vid_hdr(vid_hdr);
1256                 ubi_dbg_dump_stack();
1257                 err = 1;
1258                 goto exit;
1259         }
1260
1261         err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
1262
1263 exit:
1264         ubi_free_vid_hdr(ubi, vid_hdr);
1265         return err;
1266 }
1267
1268 /**
1269  * ubi_dbg_check_all_ff - check that a region of flash is empty.
1270  * @ubi: UBI device description object
1271  * @pnum: the physical eraseblock number to check
1272  * @offset: the starting offset within the physical eraseblock to check
1273  * @len: the length of the region to check
1274  *
1275  * This function returns zero if only 0xFF bytes are present at offset
1276  * @offset of the physical eraseblock @pnum, %1 if not, and a negative error
1277  * code if an error occurred.
1278  */
1279 int ubi_dbg_check_all_ff(struct ubi_device *ubi, int pnum, int offset, int len)
1280 {
1281         size_t read;
1282         int err;
1283         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1284
1285         mutex_lock(&ubi->dbg_buf_mutex);
1286         err = ubi->mtd->read(ubi->mtd, addr, len, &read, ubi->dbg_peb_buf);
1287         if (err && err != -EUCLEAN) {
1288                 ubi_err("error %d while reading %d bytes from PEB %d:%d, "
1289                         "read %zd bytes", err, len, pnum, offset, read);
1290                 goto error;
1291         }
1292
1293         err = check_pattern(ubi->dbg_peb_buf, 0xFF, len);
1294         if (err == 0) {
1295                 ubi_err("flash region at PEB %d:%d, length %d does not "
1296                         "contain all 0xFF bytes", pnum, offset, len);
1297                 goto fail;
1298         }
1299         mutex_unlock(&ubi->dbg_buf_mutex);
1300
1301         return 0;
1302
1303 fail:
1304         ubi_err("paranoid check failed for PEB %d", pnum);
1305         ubi_msg("hex dump of the %d-%d region", offset, offset + len);
1306         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1307                        ubi->dbg_peb_buf, len, 1);
1308         err = 1;
1309 error:
1310         ubi_dbg_dump_stack();
1311         mutex_unlock(&ubi->dbg_buf_mutex);
1312         return err;
1313 }
1314
1315 #endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */