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 <linux/slab.h>
  92 #include "ubi.h"
  93
  94 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
  95 static int paranoid_check_not_bad(const struct ubi_device *ubi, int pnum);
  96 static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum);
  97 static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
  98                                  const struct ubi_ec_hdr *ec_hdr);
  99 static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum);
 100 static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
 101                                   const struct ubi_vid_hdr *vid_hdr);
 102 #else
 103 #define paranoid_check_not_bad(ubi, pnum) 0
 104 #define paranoid_check_peb_ec_hdr(ubi, pnum)  0
 105 #define paranoid_check_ec_hdr(ubi, pnum, ec_hdr)  0
 106 #define paranoid_check_peb_vid_hdr(ubi, pnum) 0
 107 #define paranoid_check_vid_hdr(ubi, pnum, vid_hdr) 0
 108 #endif
 109
 110 /**
 111  * ubi_io_read - read data from a physical eraseblock.
 112  * @ubi: UBI device description object
 113  * @buf: buffer where to store the read data
 114  * @pnum: physical eraseblock number to read from
 115  * @offset: offset within the physical eraseblock from where to read
 116  * @len: how many bytes to read
 117  *
 118  * This function reads data from offset @offset of physical eraseblock @pnum
 119  * and stores the read data in the @buf buffer. The following return codes are
 120  * possible:
 121  *
 122  * o %0 if all the requested data were successfully read;
 123  * o %UBI_IO_BITFLIPS if all the requested data were successfully read, but
 124  *   correctable bit-flips were detected; this is harmless but may indicate
 125  *   that this eraseblock may become bad soon (but do not have to);
 126  * o %-EBADMSG if the MTD subsystem reported about data integrity problems, for
 127  *   example it can be an ECC error in case of NAND; this most probably means
 128  *   that the data is corrupted;
 129  * o %-EIO if some I/O error occurred;
 130  * o other negative error codes in case of other errors.
 131  */
 132 int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 133                 int len)
 134 {
 135         int err, retries = 0;
 136         size_t read;
 137         loff_t addr;
 138
 139         dbg_io("read %d bytes from PEB %d:%d", len, pnum, offset);
 140
 141         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 142         ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 143         ubi_assert(len > 0);
 144
 145         err = paranoid_check_not_bad(ubi, pnum);
 146         if (err)
 147                 return err;
 148
 149         addr = (loff_t)pnum * ubi->peb_size + offset;
 150 retry:
 151         err = ubi->mtd->read(ubi->mtd, addr, len, &read, buf);
 152         if (err) {
 153                 if (err == -EUCLEAN) {
 154                         /*
 155                          * -EUCLEAN is reported if there was a bit-flip which
 156                          * was corrected, so this is harmless.
 157                          *
 158                          * We do not report about it here unless debugging is
 159                          * enabled. A corresponding message will be printed
 160                          * later, when it is has been scrubbed.
 161                          */
 162                         dbg_msg("fixable bit-flip detected at PEB %d", pnum);
 163                         ubi_assert(len == read);
 164                         return UBI_IO_BITFLIPS;
 165                 }
 166
 167                 if (read != len && retries++ < UBI_IO_RETRIES) {
 168                         dbg_io("error %d while reading %d bytes from PEB %d:%d,"
 169                                " read only %zd bytes, retry",
 170                                err, len, pnum, offset, read);
 171                         yield();
 172                         goto retry;
 173                 }
 174
 175                 ubi_err("error %d while reading %d bytes from PEB %d:%d, "
 176                         "read %zd bytes", err, len, pnum, offset, read);
 177                 ubi_dbg_dump_stack();
 178
 179                 /*
 180                  * The driver should never return -EBADMSG if it failed to read
 181                  * all the requested data. But some buggy drivers might do
 182                  * this, so we change it to -EIO.
 183                  */
 184                 if (read != len && err == -EBADMSG) {
 185                         ubi_assert(0);
 186                         err = -EIO;
 187                 }
 188         } else {
 189                 ubi_assert(len == read);
 190
 191                 if (ubi_dbg_is_bitflip()) {
 192                         dbg_gen("bit-flip (emulated)");
 193                         err = UBI_IO_BITFLIPS;
 194                 }
 195         }
 196
 197         return err;
 198 }
 199
 200 /**
 201  * ubi_io_write - write data to a physical eraseblock.
 202  * @ubi: UBI device description object
 203  * @buf: buffer with the data to write
 204  * @pnum: physical eraseblock number to write to
 205  * @offset: offset within the physical eraseblock where to write
 206  * @len: how many bytes to write
 207  *
 208  * This function writes @len bytes of data from buffer @buf to offset @offset
 209  * of physical eraseblock @pnum. If all the data were successfully written,
 210  * zero is returned. If an error occurred, this function returns a negative
 211  * error code. If %-EIO is returned, the physical eraseblock most probably went
 212  * bad.
 213  *
 214  * Note, in case of an error, it is possible that something was still written
 215  * to the flash media, but may be some garbage.
 216  */
 217 int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
 218                  int len)
 219 {
 220         int err;
 221         size_t written;
 222         loff_t addr;
 223
 224         dbg_io("write %d bytes to PEB %d:%d", len, pnum, offset);
 225
 226         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 227         ubi_assert(offset >= 0 && offset + len <= ubi->peb_size);
 228         ubi_assert(offset % ubi->hdrs_min_io_size == 0);
 229         ubi_assert(len > 0 && len % ubi->hdrs_min_io_size == 0);
 230
 231         if (ubi->ro_mode) {
 232                 ubi_err("read-only mode");
 233                 return -EROFS;
 234         }
 235
 236         /* The below has to be compiled out if paranoid checks are disabled */
 237
 238         err = paranoid_check_not_bad(ubi, pnum);
 239         if (err)
 240                 return err;
 241
 242         /* The area we are writing to has to contain all 0xFF bytes */
 243         err = ubi_dbg_check_all_ff(ubi, pnum, offset, len);
 244         if (err)
 245                 return err;
 246
 247         if (offset >= ubi->leb_start) {
 248                 /*
 249                  * We write to the data area of the physical eraseblock. Make
 250                  * sure it has valid EC and VID headers.
 251                  */
 252                 err = paranoid_check_peb_ec_hdr(ubi, pnum);
 253                 if (err)
 254                         return err;
 255                 err = paranoid_check_peb_vid_hdr(ubi, pnum);
 256                 if (err)
 257                         return err;
 258         }
 259
 260         if (ubi_dbg_is_write_failure()) {
 261                 dbg_err("cannot write %d bytes to PEB %d:%d "
 262                         "(emulated)", len, pnum, offset);
 263                 ubi_dbg_dump_stack();
 264                 return -EIO;
 265         }
 266
 267         addr = (loff_t)pnum * ubi->peb_size + offset;
 268         err = ubi->mtd->write(ubi->mtd, addr, len, &written, buf);
 269         if (err) {
 270                 ubi_err("error %d while writing %d bytes to PEB %d:%d, written "
 271                         "%zd bytes", err, len, pnum, offset, written);
 272                 ubi_dbg_dump_stack();
 273                 ubi_dbg_dump_flash(ubi, pnum, offset, len);
 274         } else
 275                 ubi_assert(written == len);
 276
 277         if (!err) {
 278                 err = ubi_dbg_check_write(ubi, buf, pnum, offset, len);
 279                 if (err)
 280                         return err;
 281
 282                 /*
 283                  * Since we always write sequentially, the rest of the PEB has
 284                  * to contain only 0xFF bytes.
 285                  */
 286                 offset += len;
 287                 len = ubi->peb_size - offset;
 288                 if (len)
 289                         err = ubi_dbg_check_all_ff(ubi, pnum, offset, len);
 290         }
 291
 292         return err;
 293 }
 294
 295 /**
 296  * erase_callback - MTD erasure call-back.
 297  * @ei: MTD erase information object.
 298  *
 299  * Note, even though MTD erase interface is asynchronous, all the current
 300  * implementations are synchronous anyway.
 301  */
 302 static void erase_callback(struct erase_info *ei)
 303 {
 304         wake_up_interruptible((wait_queue_head_t *)ei->priv);
 305 }
 306
 307 /**
 308  * do_sync_erase - synchronously erase a physical eraseblock.
 309  * @ubi: UBI device description object
 310  * @pnum: the physical eraseblock number to erase
 311  *
 312  * This function synchronously erases physical eraseblock @pnum and returns
 313  * zero in case of success and a negative error code in case of failure. If
 314  * %-EIO is returned, the physical eraseblock most probably went bad.
 315  */
 316 static int do_sync_erase(struct ubi_device *ubi, int pnum)
 317 {
 318         int err, retries = 0;
 319         struct erase_info ei;
 320         wait_queue_head_t wq;
 321
 322         dbg_io("erase PEB %d", pnum);
 323
 324 retry:
 325         init_waitqueue_head(&wq);
 326         memset(&ei, 0, sizeof(struct erase_info));
 327
 328         ei.mtd      = ubi->mtd;
 329         ei.addr     = (loff_t)pnum * ubi->peb_size;
 330         ei.len      = ubi->peb_size;
 331         ei.callback = erase_callback;
 332         ei.priv     = (unsigned long)&wq;
 333
 334         err = ubi->mtd->erase(ubi->mtd, &ei);
 335         if (err) {
 336                 if (retries++ < UBI_IO_RETRIES) {
 337                         dbg_io("error %d while erasing PEB %d, retry",
 338                                err, pnum);
 339                         yield();
 340                         goto retry;
 341                 }
 342                 ubi_err("cannot erase PEB %d, error %d", pnum, err);
 343                 ubi_dbg_dump_stack();
 344                 return err;
 345         }
 346
 347         err = wait_event_interruptible(wq, ei.state == MTD_ERASE_DONE ||
 348                                            ei.state == MTD_ERASE_FAILED);
 349         if (err) {
 350                 ubi_err("interrupted PEB %d erasure", pnum);
 351                 return -EINTR;
 352         }
 353
 354         if (ei.state == MTD_ERASE_FAILED) {
 355                 if (retries++ < UBI_IO_RETRIES) {
 356                         dbg_io("error while erasing PEB %d, retry", pnum);
 357                         yield();
 358                         goto retry;
 359                 }
 360                 ubi_err("cannot erase PEB %d", pnum);
 361                 ubi_dbg_dump_stack();
 362                 return -EIO;
 363         }
 364
 365         err = ubi_dbg_check_all_ff(ubi, pnum, 0, ubi->peb_size);
 366         if (err)
 367                 return err;
 368
 369         if (ubi_dbg_is_erase_failure() && !err) {
 370                 dbg_err("cannot erase PEB %d (emulated)", pnum);
 371                 return -EIO;
 372         }
 373
 374         return 0;
 375 }
 376
 377 /**
 378  * check_pattern - check if buffer contains only a certain byte pattern.
 379  * @buf: buffer to check
 380  * @patt: the pattern to check
 381  * @size: buffer size in bytes
 382  *
 383  * This function returns %1 in there are only @patt bytes in @buf, and %0 if
 384  * something else was also found.
 385  */
 386 static int check_pattern(const void *buf, uint8_t patt, int size)
 387 {
 388         int i;
 389
 390         for (i = 0; i < size; i++)
 391                 if (((const uint8_t *)buf)[i] != patt)
 392                         return 0;
 393         return 1;
 394 }
 395
 396 /* Patterns to write to a physical eraseblock when torturing it */
 397 static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
 398
 399 /**
 400  * torture_peb - test a supposedly bad physical eraseblock.
 401  * @ubi: UBI device description object
 402  * @pnum: the physical eraseblock number to test
 403  *
 404  * This function returns %-EIO if the physical eraseblock did not pass the
 405  * test, a positive number of erase operations done if the test was
 406  * successfully passed, and other negative error codes in case of other errors.
 407  */
 408 static int torture_peb(struct ubi_device *ubi, int pnum)
 409 {
 410         int err, i, patt_count;
 411
 412         ubi_msg("run torture test for PEB %d", pnum);
 413         patt_count = ARRAY_SIZE(patterns);
 414         ubi_assert(patt_count > 0);
 415
 416         mutex_lock(&ubi->buf_mutex);
 417         for (i = 0; i < patt_count; i++) {
 418                 err = do_sync_erase(ubi, pnum);
 419                 if (err)
 420                         goto out;
 421
 422                 /* Make sure the PEB contains only 0xFF bytes */
 423                 err = ubi_io_read(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 424                 if (err)
 425                         goto out;
 426
 427                 err = check_pattern(ubi->peb_buf1, 0xFF, ubi->peb_size);
 428                 if (err == 0) {
 429                         ubi_err("erased PEB %d, but a non-0xFF byte found",
 430                                 pnum);
 431                         err = -EIO;
 432                         goto out;
 433                 }
 434
 435                 /* Write a pattern and check it */
 436                 memset(ubi->peb_buf1, patterns[i], ubi->peb_size);
 437                 err = ubi_io_write(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 438                 if (err)
 439                         goto out;
 440
 441                 memset(ubi->peb_buf1, ~patterns[i], ubi->peb_size);
 442                 err = ubi_io_read(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 443                 if (err)
 444                         goto out;
 445
 446                 err = check_pattern(ubi->peb_buf1, patterns[i], ubi->peb_size);
 447                 if (err == 0) {
 448                         ubi_err("pattern %x checking failed for PEB %d",
 449                                 patterns[i], pnum);
 450                         err = -EIO;
 451                         goto out;
 452                 }
 453         }
 454
 455         err = patt_count;
 456         ubi_msg("PEB %d passed torture test, do not mark it a bad", pnum);
 457
 458 out:
 459         mutex_unlock(&ubi->buf_mutex);
 460         if (err == UBI_IO_BITFLIPS || err == -EBADMSG) {
 461                 /*
 462                  * If a bit-flip or data integrity error was detected, the test
 463                  * has not passed because it happened on a freshly erased
 464                  * physical eraseblock which means something is wrong with it.
 465                  */
 466                 ubi_err("read problems on freshly erased PEB %d, must be bad",
 467                         pnum);
 468                 err = -EIO;
 469         }
 470         return err;
 471 }
 472
 473 /**
 474  * nor_erase_prepare - prepare a NOR flash PEB for erasure.
 475  * @ubi: UBI device description object
 476  * @pnum: physical eraseblock number to prepare
 477  *
 478  * NOR flash, or at least some of them, have peculiar embedded PEB erasure
 479  * algorithm: the PEB is first filled with zeroes, then it is erased. And
 480  * filling with zeroes starts from the end of the PEB. This was observed with
 481  * Spansion S29GL512N NOR flash.
 482  *
 483  * This means that in case of a power cut we may end up with intact data at the
 484  * beginning of the PEB, and all zeroes at the end of PEB. In other words, the
 485  * EC and VID headers are OK, but a large chunk of data at the end of PEB is
 486  * zeroed. This makes UBI mistakenly treat this PEB as used and associate it
 487  * with an LEB, which leads to subsequent failures (e.g., UBIFS fails).
 488  *
 489  * This function is called before erasing NOR PEBs and it zeroes out EC and VID
 490  * magic numbers in order to invalidate them and prevent the failures. Returns
 491  * zero in case of success and a negative error code in case of failure.
 492  */
 493 static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 494 {
 495         int err, err1;
 496         size_t written;
 497         loff_t addr;
 498         uint32_t data = 0;
 499         struct ubi_vid_hdr vid_hdr;
 500
 501         addr = (loff_t)pnum * ubi->peb_size + ubi->vid_hdr_aloffset;
 502         err = ubi->mtd->write(ubi->mtd, addr, 4, &written, (void *)&data);
 503         if (!err) {
 504                 addr -= ubi->vid_hdr_aloffset;
 505                 err = ubi->mtd->write(ubi->mtd, addr, 4, &written,
 506                                       (void *)&data);
 507                 if (!err)
 508                         return 0;
 509         }
 510
 511         /*
 512          * We failed to write to the media. This was observed with Spansion
 513          * S29GL512N NOR flash. Most probably the eraseblock erasure was
 514          * interrupted at a very inappropriate moment, so it became unwritable.
 515          * In this case we probably anyway have garbage in this PEB.
 516          */
 517         err1 = ubi_io_read_vid_hdr(ubi, pnum, &vid_hdr, 0);
 518         if (err1 == UBI_IO_BAD_VID_HDR)
 519                 /*
 520                  * The VID header is corrupted, so we can safely erase this
 521                  * PEB and not afraid that it will be treated as a valid PEB in
 522                  * case of an unclean reboot.
 523                  */
 524                 return 0;
 525
 526         /*
 527          * The PEB contains a valid VID header, but we cannot invalidate it.
 528          * Supposedly the flash media or the driver is screwed up, so return an
 529          * error.
 530          */
 531         ubi_err("cannot invalidate PEB %d, write returned %d read returned %d",
 532                 pnum, err, err1);
 533         ubi_dbg_dump_flash(ubi, pnum, 0, ubi->peb_size);
 534         return -EIO;
 535 }
 536
 537 /**
 538  * ubi_io_sync_erase - synchronously erase a physical eraseblock.
 539  * @ubi: UBI device description object
 540  * @pnum: physical eraseblock number to erase
 541  * @torture: if this physical eraseblock has to be tortured
 542  *
 543  * This function synchronously erases physical eraseblock @pnum. If @torture
 544  * flag is not zero, the physical eraseblock is checked by means of writing
 545  * different patterns to it and reading them back. If the torturing is enabled,
 546  * the physical eraseblock is erased more than once.
 547  *
 548  * This function returns the number of erasures made in case of success, %-EIO
 549  * if the erasure failed or the torturing test failed, and other negative error
 550  * codes in case of other errors. Note, %-EIO means that the physical
 551  * eraseblock is bad.
 552  */
 553 int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
 554 {
 555         int err, ret = 0;
 556
 557         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 558
 559         err = paranoid_check_not_bad(ubi, pnum);
 560         if (err != 0)
 561                 return err;
 562
 563         if (ubi->ro_mode) {
 564                 ubi_err("read-only mode");
 565                 return -EROFS;
 566         }
 567
 568         if (ubi->nor_flash) {
 569                 err = nor_erase_prepare(ubi, pnum);
 570                 if (err)
 571                         return err;
 572         }
 573
 574         if (torture) {
 575                 ret = torture_peb(ubi, pnum);
 576                 if (ret < 0)
 577                         return ret;
 578         }
 579
 580         err = do_sync_erase(ubi, pnum);
 581         if (err)
 582                 return err;
 583
 584         return ret + 1;
 585 }
 586
 587 /**
 588  * ubi_io_is_bad - check if a physical eraseblock is bad.
 589  * @ubi: UBI device description object
 590  * @pnum: the physical eraseblock number to check
 591  *
 592  * This function returns a positive number if the physical eraseblock is bad,
 593  * zero if not, and a negative error code if an error occurred.
 594  */
 595 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum)
 596 {
 597         struct mtd_info *mtd = ubi->mtd;
 598
 599         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 600
 601         if (ubi->bad_allowed) {
 602                 int ret;
 603
 604                 ret = mtd->block_isbad(mtd, (loff_t)pnum * ubi->peb_size);
 605                 if (ret < 0)
 606                         ubi_err("error %d while checking if PEB %d is bad",
 607                                 ret, pnum);
 608                 else if (ret)
 609                         dbg_io("PEB %d is bad", pnum);
 610                 return ret;
 611         }
 612
 613         return 0;
 614 }
 615
 616 /**
 617  * ubi_io_mark_bad - mark a physical eraseblock as bad.
 618  * @ubi: UBI device description object
 619  * @pnum: the physical eraseblock number to mark
 620  *
 621  * This function returns zero in case of success and a negative error code in
 622  * case of failure.
 623  */
 624 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
 625 {
 626         int err;
 627         struct mtd_info *mtd = ubi->mtd;
 628
 629         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 630
 631         if (ubi->ro_mode) {
 632                 ubi_err("read-only mode");
 633                 return -EROFS;
 634         }
 635
 636         if (!ubi->bad_allowed)
 637                 return 0;
 638
 639         err = mtd->block_markbad(mtd, (loff_t)pnum * ubi->peb_size);
 640         if (err)
 641                 ubi_err("cannot mark PEB %d bad, error %d", pnum, err);
 642         return err;
 643 }
 644
 645 /**
 646  * validate_ec_hdr - validate an erase counter header.
 647  * @ubi: UBI device description object
 648  * @ec_hdr: the erase counter header to check
 649  *
 650  * This function returns zero if the erase counter header is OK, and %1 if
 651  * not.
 652  */
 653 static int validate_ec_hdr(const struct ubi_device *ubi,
 654                            const struct ubi_ec_hdr *ec_hdr)
 655 {
 656         long long ec;
 657         int vid_hdr_offset, leb_start;
 658
 659         ec = be64_to_cpu(ec_hdr->ec);
 660         vid_hdr_offset = be32_to_cpu(ec_hdr->vid_hdr_offset);
 661         leb_start = be32_to_cpu(ec_hdr->data_offset);
 662
 663         if (ec_hdr->version != UBI_VERSION) {
 664                 ubi_err("node with incompatible UBI version found: "
 665                         "this UBI version is %d, image version is %d",
 666                         UBI_VERSION, (int)ec_hdr->version);
 667                 goto bad;
 668         }
 669
 670         if (vid_hdr_offset != ubi->vid_hdr_offset) {
 671                 ubi_err("bad VID header offset %d, expected %d",
 672                         vid_hdr_offset, ubi->vid_hdr_offset);
 673                 goto bad;
 674         }
 675
 676         if (leb_start != ubi->leb_start) {
 677                 ubi_err("bad data offset %d, expected %d",
 678                         leb_start, ubi->leb_start);
 679                 goto bad;
 680         }
 681
 682         if (ec < 0 || ec > UBI_MAX_ERASECOUNTER) {
 683                 ubi_err("bad erase counter %lld", ec);
 684                 goto bad;
 685         }
 686
 687         return 0;
 688
 689 bad:
 690         ubi_err("bad EC header");
 691         ubi_dbg_dump_ec_hdr(ec_hdr);
 692         ubi_dbg_dump_stack();
 693         return 1;
 694 }
 695
 696 /**
 697  * ubi_io_read_ec_hdr - read and check an erase counter header.
 698  * @ubi: UBI device description object
 699  * @pnum: physical eraseblock to read from
 700  * @ec_hdr: a &struct ubi_ec_hdr object where to store the read erase counter
 701  * header
 702  * @verbose: be verbose if the header is corrupted or was not found
 703  *
 704  * This function reads erase counter header from physical eraseblock @pnum and
 705  * stores it in @ec_hdr. This function also checks CRC checksum of the read
 706  * erase counter header. The following codes may be returned:
 707  *
 708  * o %0 if the CRC checksum is correct and the header was successfully read;
 709  * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 710  *   and corrected by the flash driver; this is harmless but may indicate that
 711  *   this eraseblock may become bad soon (but may be not);
 712  * o %UBI_IO_BAD_EC_HDR if the erase counter header is corrupted (a CRC error);
 713  * o %UBI_IO_PEB_EMPTY if the physical eraseblock is empty;
 714  * o a negative error code in case of failure.
 715  */
 716 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 717                        struct ubi_ec_hdr *ec_hdr, int verbose)
 718 {
 719         int err, read_err = 0;
 720         uint32_t crc, magic, hdr_crc;
 721
 722         dbg_io("read EC header from PEB %d", pnum);
 723         ubi_assert(pnum >= 0 && pnum < ubi->peb_count);
 724
 725         err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
 726         if (err) {
 727                 if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
 728                         return err;
 729
 730                 /*
 731                  * We read all the data, but either a correctable bit-flip
 732                  * occurred, or MTD reported about some data integrity error,
 733                  * like an ECC error in case of NAND. The former is harmless,
 734                  * the later may mean that the read data is corrupted. But we
 735                  * have a CRC check-sum and we will detect this. If the EC
 736                  * header is still OK, we just report this as there was a
 737                  * bit-flip.
 738                  */
 739                 read_err = err;
 740         }
 741
 742         magic = be32_to_cpu(ec_hdr->magic);
 743         if (magic != UBI_EC_HDR_MAGIC) {
 744                 /*
 745                  * The magic field is wrong. Let's check if we have read all
 746                  * 0xFF. If yes, this physical eraseblock is assumed to be
 747                  * empty.
 748                  *
 749                  * But if there was a read error, we do not test it for all
 750                  * 0xFFs. Even if it does contain all 0xFFs, this error
 751                  * indicates that something is still wrong with this physical
 752                  * eraseblock and we anyway cannot treat it as empty.
 753                  */
 754                 if (read_err != -EBADMSG &&
 755                     check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) {
 756                         /* The physical eraseblock is supposedly empty */
 757                         if (verbose)
 758                                 ubi_warn("no EC header found at PEB %d, "
 759                                          "only 0xFF bytes", pnum);
 760                         else if (UBI_IO_DEBUG)
 761                                 dbg_msg("no EC header found at PEB %d, "
 762                                         "only 0xFF bytes", pnum);
 763                         return UBI_IO_PEB_EMPTY;
 764                 }
 765
 766                 /*
 767                  * This is not a valid erase counter header, and these are not
 768                  * 0xFF bytes. Report that the header is corrupted.
 769                  */
 770                 if (verbose) {
 771                         ubi_warn("bad magic number at PEB %d: %08x instead of "
 772                                  "%08x", pnum, magic, UBI_EC_HDR_MAGIC);
 773                         ubi_dbg_dump_ec_hdr(ec_hdr);
 774                 } else if (UBI_IO_DEBUG)
 775                         dbg_msg("bad magic number at PEB %d: %08x instead of "
 776                                 "%08x", pnum, magic, UBI_EC_HDR_MAGIC);
 777                 return UBI_IO_BAD_EC_HDR;
 778         }
 779
 780         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 781         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
 782
 783         if (hdr_crc != crc) {
 784                 if (verbose) {
 785                         ubi_warn("bad EC header CRC at PEB %d, calculated "
 786                                  "%#08x, read %#08x", pnum, crc, hdr_crc);
 787                         ubi_dbg_dump_ec_hdr(ec_hdr);
 788                 } else if (UBI_IO_DEBUG)
 789                         dbg_msg("bad EC header CRC at PEB %d, calculated "
 790                                 "%#08x, read %#08x", pnum, crc, hdr_crc);
 791                 return UBI_IO_BAD_EC_HDR;
 792         }
 793
 794         /* And of course validate what has just been read from the media */
 795         err = validate_ec_hdr(ubi, ec_hdr);
 796         if (err) {
 797                 ubi_err("validation failed for PEB %d", pnum);
 798                 return -EINVAL;
 799         }
 800
 801         return read_err ? UBI_IO_BITFLIPS : 0;
 802 }
 803
 804 /**
 805  * ubi_io_write_ec_hdr - write an erase counter header.
 806  * @ubi: UBI device description object
 807  * @pnum: physical eraseblock to write to
 808  * @ec_hdr: the erase counter header to write
 809  *
 810  * This function writes erase counter header described by @ec_hdr to physical
 811  * eraseblock @pnum. It also fills most fields of @ec_hdr before writing, so
 812  * the caller do not have to fill them. Callers must only fill the @ec_hdr->ec
 813  * field.
 814  *
 815  * This function returns zero in case of success and a negative error code in
 816  * case of failure. If %-EIO is returned, the physical eraseblock most probably
 817  * went bad.
 818  */
 819 int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 820                         struct ubi_ec_hdr *ec_hdr)
 821 {
 822         int err;
 823         uint32_t crc;
 824
 825         dbg_io("write EC header to PEB %d", pnum);
 826         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 827
 828         ec_hdr->magic = cpu_to_be32(UBI_EC_HDR_MAGIC);
 829         ec_hdr->version = UBI_VERSION;
 830         ec_hdr->vid_hdr_offset = cpu_to_be32(ubi->vid_hdr_offset);
 831         ec_hdr->data_offset = cpu_to_be32(ubi->leb_start);
 832         ec_hdr->image_seq = cpu_to_be32(ubi->image_seq);
 833         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
 834         ec_hdr->hdr_crc = cpu_to_be32(crc);
 835
 836         err = paranoid_check_ec_hdr(ubi, pnum, ec_hdr);
 837         if (err)
 838                 return err;
 839
 840         err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
 841         return err;
 842 }
 843
 844 /**
 845  * validate_vid_hdr - validate a volume identifier header.
 846  * @ubi: UBI device description object
 847  * @vid_hdr: the volume identifier header to check
 848  *
 849  * This function checks that data stored in the volume identifier header
 850  * @vid_hdr. Returns zero if the VID header is OK and %1 if not.
 851  */
 852 static int validate_vid_hdr(const struct ubi_device *ubi,
 853                             const struct ubi_vid_hdr *vid_hdr)
 854 {
 855         int vol_type = vid_hdr->vol_type;
 856         int copy_flag = vid_hdr->copy_flag;
 857         int vol_id = be32_to_cpu(vid_hdr->vol_id);
 858         int lnum = be32_to_cpu(vid_hdr->lnum);
 859         int compat = vid_hdr->compat;
 860         int data_size = be32_to_cpu(vid_hdr->data_size);
 861         int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
 862         int data_pad = be32_to_cpu(vid_hdr->data_pad);
 863         int data_crc = be32_to_cpu(vid_hdr->data_crc);
 864         int usable_leb_size = ubi->leb_size - data_pad;
 865
 866         if (copy_flag != 0 && copy_flag != 1) {
 867                 dbg_err("bad copy_flag");
 868                 goto bad;
 869         }
 870
 871         if (vol_id < 0 || lnum < 0 || data_size < 0 || used_ebs < 0 ||
 872             data_pad < 0) {
 873                 dbg_err("negative values");
 874                 goto bad;
 875         }
 876
 877         if (vol_id >= UBI_MAX_VOLUMES && vol_id < UBI_INTERNAL_VOL_START) {
 878                 dbg_err("bad vol_id");
 879                 goto bad;
 880         }
 881
 882         if (vol_id < UBI_INTERNAL_VOL_START && compat != 0) {
 883                 dbg_err("bad compat");
 884                 goto bad;
 885         }
 886
 887         if (vol_id >= UBI_INTERNAL_VOL_START && compat != UBI_COMPAT_DELETE &&
 888             compat != UBI_COMPAT_RO && compat != UBI_COMPAT_PRESERVE &&
 889             compat != UBI_COMPAT_REJECT) {
 890                 dbg_err("bad compat");
 891                 goto bad;
 892         }
 893
 894         if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
 895                 dbg_err("bad vol_type");
 896                 goto bad;
 897         }
 898
 899         if (data_pad >= ubi->leb_size / 2) {
 900                 dbg_err("bad data_pad");
 901                 goto bad;
 902         }
 903
 904         if (vol_type == UBI_VID_STATIC) {
 905                 /*
 906                  * Although from high-level point of view static volumes may
 907                  * contain zero bytes of data, but no VID headers can contain
 908                  * zero at these fields, because they empty volumes do not have
 909                  * mapped logical eraseblocks.
 910                  */
 911                 if (used_ebs == 0) {
 912                         dbg_err("zero used_ebs");
 913                         goto bad;
 914                 }
 915                 if (data_size == 0) {
 916                         dbg_err("zero data_size");
 917                         goto bad;
 918                 }
 919                 if (lnum < used_ebs - 1) {
 920                         if (data_size != usable_leb_size) {
 921                                 dbg_err("bad data_size");
 922                                 goto bad;
 923                         }
 924                 } else if (lnum == used_ebs - 1) {
 925                         if (data_size == 0) {
 926                                 dbg_err("bad data_size at last LEB");
 927                                 goto bad;
 928                         }
 929                 } else {
 930                         dbg_err("too high lnum");
 931                         goto bad;
 932                 }
 933         } else {
 934                 if (copy_flag == 0) {
 935                         if (data_crc != 0) {
 936                                 dbg_err("non-zero data CRC");
 937                                 goto bad;
 938                         }
 939                         if (data_size != 0) {
 940                                 dbg_err("non-zero data_size");
 941                                 goto bad;
 942                         }
 943                 } else {
 944                         if (data_size == 0) {
 945                                 dbg_err("zero data_size of copy");
 946                                 goto bad;
 947                         }
 948                 }
 949                 if (used_ebs != 0) {
 950                         dbg_err("bad used_ebs");
 951                         goto bad;
 952                 }
 953         }
 954
 955         return 0;
 956
 957 bad:
 958         ubi_err("bad VID header");
 959         ubi_dbg_dump_vid_hdr(vid_hdr);
 960         ubi_dbg_dump_stack();
 961         return 1;
 962 }
 963
 964 /**
 965  * ubi_io_read_vid_hdr - read and check a volume identifier header.
 966  * @ubi: UBI device description object
 967  * @pnum: physical eraseblock number to read from
 968  * @vid_hdr: &struct ubi_vid_hdr object where to store the read volume
 969  * identifier header
 970  * @verbose: be verbose if the header is corrupted or wasn't found
 971  *
 972  * This function reads the volume identifier header from physical eraseblock
 973  * @pnum and stores it in @vid_hdr. It also checks CRC checksum of the read
 974  * volume identifier header. The following codes may be returned:
 975  *
 976  * o %0 if the CRC checksum is correct and the header was successfully read;
 977  * o %UBI_IO_BITFLIPS if the CRC is correct, but bit-flips were detected
 978  *   and corrected by the flash driver; this is harmless but may indicate that
 979  *   this eraseblock may become bad soon;
 980  * o %UBI_IO_BAD_VID_HDR if the volume identifier header is corrupted (a CRC
 981  *   error detected);
 982  * o %UBI_IO_PEB_FREE if the physical eraseblock is free (i.e., there is no VID
 983  *   header there);
 984  * o a negative error code in case of failure.
 985  */
 986 int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 987                         struct ubi_vid_hdr *vid_hdr, int verbose)
 988 {
 989         int err, read_err = 0;
 990         uint32_t crc, magic, hdr_crc;
 991         void *p;
 992
 993         dbg_io("read VID header from PEB %d", pnum);
 994         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
 995
 996         p = (char *)vid_hdr - ubi->vid_hdr_shift;
 997         err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
 998                           ubi->vid_hdr_alsize);
 999         if (err) {
1000                 if (err != UBI_IO_BITFLIPS && err != -EBADMSG)
1001                         return err;
1002
1003                 /*
1004                  * We read all the data, but either a correctable bit-flip
1005                  * occurred, or MTD reported about some data integrity error,
1006                  * like an ECC error in case of NAND. The former is harmless,
1007                  * the later may mean the read data is corrupted. But we have a
1008                  * CRC check-sum and we will identify this. If the VID header is
1009                  * still OK, we just report this as there was a bit-flip.
1010                  */
1011                 read_err = err;
1012         }
1013
1014         magic = be32_to_cpu(vid_hdr->magic);
1015         if (magic != UBI_VID_HDR_MAGIC) {
1016                 /*
1017                  * If we have read all 0xFF bytes, the VID header probably does
1018                  * not exist and the physical eraseblock is assumed to be free.
1019                  *
1020                  * But if there was a read error, we do not test the data for
1021                  * 0xFFs. Even if it does contain all 0xFFs, this error
1022                  * indicates that something is still wrong with this physical
1023                  * eraseblock and it cannot be regarded as free.
1024                  */
1025                 if (read_err != -EBADMSG &&
1026                     check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) {
1027                         /* The physical eraseblock is supposedly free */
1028                         if (verbose)
1029                                 ubi_warn("no VID header found at PEB %d, "
1030                                          "only 0xFF bytes", pnum);
1031                         else if (UBI_IO_DEBUG)
1032                                 dbg_msg("no VID header found at PEB %d, "
1033                                         "only 0xFF bytes", pnum);
1034                         return UBI_IO_PEB_FREE;
1035                 }
1036
1037                 /*
1038                  * This is not a valid VID header, and these are not 0xFF
1039                  * bytes. Report that the header is corrupted.
1040                  */
1041                 if (verbose) {
1042                         ubi_warn("bad magic number at PEB %d: %08x instead of "
1043                                  "%08x", pnum, magic, UBI_VID_HDR_MAGIC);
1044                         ubi_dbg_dump_vid_hdr(vid_hdr);
1045                 } else if (UBI_IO_DEBUG)
1046                         dbg_msg("bad magic number at PEB %d: %08x instead of "
1047                                 "%08x", pnum, magic, UBI_VID_HDR_MAGIC);
1048                 return UBI_IO_BAD_VID_HDR;
1049         }
1050
1051         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1052         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1053
1054         if (hdr_crc != crc) {
1055                 if (verbose) {
1056                         ubi_warn("bad CRC at PEB %d, calculated %#08x, "
1057                                  "read %#08x", pnum, crc, hdr_crc);
1058                         ubi_dbg_dump_vid_hdr(vid_hdr);
1059                 } else if (UBI_IO_DEBUG)
1060                         dbg_msg("bad CRC at PEB %d, calculated %#08x, "
1061                                 "read %#08x", pnum, crc, hdr_crc);
1062                 return UBI_IO_BAD_VID_HDR;
1063         }
1064
1065         /* Validate the VID header that we have just read */
1066         err = validate_vid_hdr(ubi, vid_hdr);
1067         if (err) {
1068                 ubi_err("validation failed for PEB %d", pnum);
1069                 return -EINVAL;
1070         }
1071
1072         return read_err ? UBI_IO_BITFLIPS : 0;
1073 }
1074
1075 /**
1076  * ubi_io_write_vid_hdr - write a volume identifier header.
1077  * @ubi: UBI device description object
1078  * @pnum: the physical eraseblock number to write to
1079  * @vid_hdr: the volume identifier header to write
1080  *
1081  * This function writes the volume identifier header described by @vid_hdr to
1082  * physical eraseblock @pnum. This function automatically fills the
1083  * @vid_hdr->magic and the @vid_hdr->version fields, as well as calculates
1084  * header CRC checksum and stores it at vid_hdr->hdr_crc.
1085  *
1086  * This function returns zero in case of success and a negative error code in
1087  * case of failure. If %-EIO is returned, the physical eraseblock probably went
1088  * bad.
1089  */
1090 int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
1091                          struct ubi_vid_hdr *vid_hdr)
1092 {
1093         int err;
1094         uint32_t crc;
1095         void *p;
1096
1097         dbg_io("write VID header to PEB %d", pnum);
1098         ubi_assert(pnum >= 0 &&  pnum < ubi->peb_count);
1099
1100         err = paranoid_check_peb_ec_hdr(ubi, pnum);
1101         if (err)
1102                 return err;
1103
1104         vid_hdr->magic = cpu_to_be32(UBI_VID_HDR_MAGIC);
1105         vid_hdr->version = UBI_VERSION;
1106         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_VID_HDR_SIZE_CRC);
1107         vid_hdr->hdr_crc = cpu_to_be32(crc);
1108
1109         err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
1110         if (err)
1111                 return err;
1112
1113         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1114         err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
1115                            ubi->vid_hdr_alsize);
1116         return err;
1117 }
1118
1119 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
1120
1121 /**
1122  * paranoid_check_not_bad - ensure that a physical eraseblock is not bad.
1123  * @ubi: UBI device description object
1124  * @pnum: physical eraseblock number to check
1125  *
1126  * This function returns zero if the physical eraseblock is good, %-EINVAL if
1127  * it is bad and a negative error code if an error occurred.
1128  */
1129 static int paranoid_check_not_bad(const struct ubi_device *ubi, int pnum)
1130 {
1131         int err;
1132
1133         err = ubi_io_is_bad(ubi, pnum);
1134         if (!err)
1135                 return err;
1136
1137         ubi_err("paranoid check failed for PEB %d", pnum);
1138         ubi_dbg_dump_stack();
1139         return err > 0 ? -EINVAL : err;
1140 }
1141
1142 /**
1143  * paranoid_check_ec_hdr - check if an erase counter header is all right.
1144  * @ubi: UBI device description object
1145  * @pnum: physical eraseblock number the erase counter header belongs to
1146  * @ec_hdr: the erase counter header to check
1147  *
1148  * This function returns zero if the erase counter header contains valid
1149  * values, and %-EINVAL if not.
1150  */
1151 static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
1152                                  const struct ubi_ec_hdr *ec_hdr)
1153 {
1154         int err;
1155         uint32_t magic;
1156
1157         magic = be32_to_cpu(ec_hdr->magic);
1158         if (magic != UBI_EC_HDR_MAGIC) {
1159                 ubi_err("bad magic %#08x, must be %#08x",
1160                         magic, UBI_EC_HDR_MAGIC);
1161                 goto fail;
1162         }
1163
1164         err = validate_ec_hdr(ubi, ec_hdr);
1165         if (err) {
1166                 ubi_err("paranoid check failed for PEB %d", pnum);
1167                 goto fail;
1168         }
1169
1170         return 0;
1171
1172 fail:
1173         ubi_dbg_dump_ec_hdr(ec_hdr);
1174         ubi_dbg_dump_stack();
1175         return -EINVAL;
1176 }
1177
1178 /**
1179  * paranoid_check_peb_ec_hdr - check erase counter header.
1180  * @ubi: UBI device description object
1181  * @pnum: the physical eraseblock number to check
1182  *
1183  * This function returns zero if the erase counter header is all right and and
1184  * a negative error code if not or if an error occurred.
1185  */
1186 static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
1187 {
1188         int err;
1189         uint32_t crc, hdr_crc;
1190         struct ubi_ec_hdr *ec_hdr;
1191
1192         ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
1193         if (!ec_hdr)
1194                 return -ENOMEM;
1195
1196         err = ubi_io_read(ubi, ec_hdr, pnum, 0, UBI_EC_HDR_SIZE);
1197         if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
1198                 goto exit;
1199
1200         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
1201         hdr_crc = be32_to_cpu(ec_hdr->hdr_crc);
1202         if (hdr_crc != crc) {
1203                 ubi_err("bad CRC, calculated %#08x, read %#08x", crc, hdr_crc);
1204                 ubi_err("paranoid check failed for PEB %d", pnum);
1205                 ubi_dbg_dump_ec_hdr(ec_hdr);
1206                 ubi_dbg_dump_stack();
1207                 err = -EINVAL;
1208                 goto exit;
1209         }
1210
1211         err = paranoid_check_ec_hdr(ubi, pnum, ec_hdr);
1212
1213 exit:
1214         kfree(ec_hdr);
1215         return err;
1216 }
1217
1218 /**
1219  * paranoid_check_vid_hdr - check that a volume identifier header is all right.
1220  * @ubi: UBI device description object
1221  * @pnum: physical eraseblock number the volume identifier header belongs to
1222  * @vid_hdr: the volume identifier header to check
1223  *
1224  * This function returns zero if the volume identifier header is all right, and
1225  * %-EINVAL if not.
1226  */
1227 static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
1228                                   const struct ubi_vid_hdr *vid_hdr)
1229 {
1230         int err;
1231         uint32_t magic;
1232
1233         magic = be32_to_cpu(vid_hdr->magic);
1234         if (magic != UBI_VID_HDR_MAGIC) {
1235                 ubi_err("bad VID header magic %#08x at PEB %d, must be %#08x",
1236                         magic, pnum, UBI_VID_HDR_MAGIC);
1237                 goto fail;
1238         }
1239
1240         err = validate_vid_hdr(ubi, vid_hdr);
1241         if (err) {
1242                 ubi_err("paranoid check failed for PEB %d", pnum);
1243                 goto fail;
1244         }
1245
1246         return err;
1247
1248 fail:
1249         ubi_err("paranoid check failed for PEB %d", pnum);
1250         ubi_dbg_dump_vid_hdr(vid_hdr);
1251         ubi_dbg_dump_stack();
1252         return -EINVAL;
1253
1254 }
1255
1256 /**
1257  * paranoid_check_peb_vid_hdr - check volume identifier header.
1258  * @ubi: UBI device description object
1259  * @pnum: the physical eraseblock number to check
1260  *
1261  * This function returns zero if the volume identifier header is all right,
1262  * and a negative error code if not or if an error occurred.
1263  */
1264 static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
1265 {
1266         int err;
1267         uint32_t crc, hdr_crc;
1268         struct ubi_vid_hdr *vid_hdr;
1269         void *p;
1270
1271         vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
1272         if (!vid_hdr)
1273                 return -ENOMEM;
1274
1275         p = (char *)vid_hdr - ubi->vid_hdr_shift;
1276         err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,
1277                           ubi->vid_hdr_alsize);
1278         if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
1279                 goto exit;
1280
1281         crc = crc32(UBI_CRC32_INIT, vid_hdr, UBI_EC_HDR_SIZE_CRC);
1282         hdr_crc = be32_to_cpu(vid_hdr->hdr_crc);
1283         if (hdr_crc != crc) {
1284                 ubi_err("bad VID header CRC at PEB %d, calculated %#08x, "
1285                         "read %#08x", pnum, crc, hdr_crc);
1286                 ubi_err("paranoid check failed for PEB %d", pnum);
1287                 ubi_dbg_dump_vid_hdr(vid_hdr);
1288                 ubi_dbg_dump_stack();
1289                 err = -EINVAL;
1290                 goto exit;
1291         }
1292
1293         err = paranoid_check_vid_hdr(ubi, pnum, vid_hdr);
1294
1295 exit:
1296         ubi_free_vid_hdr(ubi, vid_hdr);
1297         return err;
1298 }
1299
1300 /**
1301  * ubi_dbg_check_write - make sure write succeeded.
1302  * @ubi: UBI device description object
1303  * @buf: buffer with data which were written
1304  * @pnum: physical eraseblock number the data were written to
1305  * @offset: offset within the physical eraseblock the data were written to
1306  * @len: how many bytes were written
1307  *
1308  * This functions reads data which were recently written and compares it with
1309  * the original data buffer - the data have to match. Returns zero if the data
1310  * match and a negative error code if not or in case of failure.
1311  */
1312 int ubi_dbg_check_write(struct ubi_device *ubi, const void *buf, int pnum,
1313                         int offset, int len)
1314 {
1315         int err, i;
1316
1317         mutex_lock(&ubi->dbg_buf_mutex);
1318         err = ubi_io_read(ubi, ubi->dbg_peb_buf, pnum, offset, len);
1319         if (err)
1320                 goto out_unlock;
1321
1322         for (i = 0; i < len; i++) {
1323                 uint8_t c = ((uint8_t *)buf)[i];
1324                 uint8_t c1 = ((uint8_t *)ubi->dbg_peb_buf)[i];
1325                 int dump_len;
1326
1327                 if (c == c1)
1328                         continue;
1329
1330                 ubi_err("paranoid check failed for PEB %d:%d, len %d",
1331                         pnum, offset, len);
1332                 ubi_msg("data differ at position %d", i);
1333                 dump_len = max_t(int, 128, len - i);
1334                 ubi_msg("hex dump of the original buffer from %d to %d",
1335                         i, i + dump_len);
1336                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1337                                buf + i, dump_len, 1);
1338                 ubi_msg("hex dump of the read buffer from %d to %d",
1339                         i, i + dump_len);
1340                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1341                                ubi->dbg_peb_buf + i, dump_len, 1);
1342                 ubi_dbg_dump_stack();
1343                 err = -EINVAL;
1344                 goto out_unlock;
1345         }
1346         mutex_unlock(&ubi->dbg_buf_mutex);
1347
1348         return 0;
1349
1350 out_unlock:
1351         mutex_unlock(&ubi->dbg_buf_mutex);
1352         return err;
1353 }
1354
1355 /**
1356  * ubi_dbg_check_all_ff - check that a region of flash is empty.
1357  * @ubi: UBI device description object
1358  * @pnum: the physical eraseblock number to check
1359  * @offset: the starting offset within the physical eraseblock to check
1360  * @len: the length of the region to check
1361  *
1362  * This function returns zero if only 0xFF bytes are present at offset
1363  * @offset of the physical eraseblock @pnum, and a negative error code if not
1364  * or if an error occurred.
1365  */
1366 int ubi_dbg_check_all_ff(struct ubi_device *ubi, int pnum, int offset, int len)
1367 {
1368         size_t read;
1369         int err;
1370         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
1371
1372         mutex_lock(&ubi->dbg_buf_mutex);
1373         err = ubi->mtd->read(ubi->mtd, addr, len, &read, ubi->dbg_peb_buf);
1374         if (err && err != -EUCLEAN) {
1375                 ubi_err("error %d while reading %d bytes from PEB %d:%d, "
1376                         "read %zd bytes", err, len, pnum, offset, read);
1377                 goto error;
1378         }
1379
1380         err = check_pattern(ubi->dbg_peb_buf, 0xFF, len);
1381         if (err == 0) {
1382                 ubi_err("flash region at PEB %d:%d, length %d does not "
1383                         "contain all 0xFF bytes", pnum, offset, len);
1384                 goto fail;
1385         }
1386         mutex_unlock(&ubi->dbg_buf_mutex);
1387
1388         return 0;
1389
1390 fail:
1391         ubi_err("paranoid check failed for PEB %d", pnum);
1392         ubi_msg("hex dump of the %d-%d region", offset, offset + len);
1393         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
1394                        ubi->dbg_peb_buf, len, 1);
1395         err = -EINVAL;
1396 error:
1397         ubi_dbg_dump_stack();
1398         mutex_unlock(&ubi->dbg_buf_mutex);
1399         return err;
1400 }
1401
1402 #endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */