drivers/mtd/ubi/kapi.c

   1 /*
   2  * Copyright (c) International Business Machines Corp., 2006
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
  12  * the GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  17  *
  18  * Author: Artem Bityutskiy (Битюцкий Артём)
  19  */
  20
  21 /* This file mostly implements UBI kernel API functions */
  22
  23 #include <linux/module.h>
  24 #include <linux/err.h>
  25 #include <asm/div64.h>
  26 #include "ubi.h"
  27
  28 /**
  29  * ubi_get_device_info - get information about UBI device.
  30  * @ubi_num: UBI device number
  31  * @di: the information is stored here
  32  *
  33  * This function returns %0 in case of success and a %-ENODEV if there is no
  34  * such UBI device.
  35  */
  36 int ubi_get_device_info(int ubi_num, struct ubi_device_info *di)
  37 {
  38         const struct ubi_device *ubi;
  39
  40         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES ||
  41             !ubi_devices[ubi_num])
  42                 return -ENODEV;
  43
  44         ubi = ubi_devices[ubi_num];
  45         di->ubi_num = ubi->ubi_num;
  46         di->leb_size = ubi->leb_size;
  47         di->min_io_size = ubi->min_io_size;
  48         di->ro_mode = ubi->ro_mode;
  49         di->cdev = MKDEV(ubi->major, 0);
  50         return 0;
  51 }
  52 EXPORT_SYMBOL_GPL(ubi_get_device_info);
  53
  54 /**
  55  * ubi_get_volume_info - get information about UBI volume.
  56  * @desc: volume descriptor
  57  * @vi: the information is stored here
  58  */
  59 void ubi_get_volume_info(struct ubi_volume_desc *desc,
  60                          struct ubi_volume_info *vi)
  61 {
  62         const struct ubi_volume *vol = desc->vol;
  63         const struct ubi_device *ubi = vol->ubi;
  64
  65         vi->vol_id = vol->vol_id;
  66         vi->ubi_num = ubi->ubi_num;
  67         vi->size = vol->reserved_pebs;
  68         vi->used_bytes = vol->used_bytes;
  69         vi->vol_type = vol->vol_type;
  70         vi->corrupted = vol->corrupted;
  71         vi->upd_marker = vol->upd_marker;
  72         vi->alignment = vol->alignment;
  73         vi->usable_leb_size = vol->usable_leb_size;
  74         vi->name_len = vol->name_len;
  75         vi->name = vol->name;
  76         vi->cdev = MKDEV(ubi->major, vi->vol_id + 1);
  77 }
  78 EXPORT_SYMBOL_GPL(ubi_get_volume_info);
  79
  80 /**
  81  * ubi_open_volume - open UBI volume.
  82  * @ubi_num: UBI device number
  83  * @vol_id: volume ID
  84  * @mode: open mode
  85  *
  86  * The @mode parameter specifies if the volume should be opened in read-only
  87  * mode, read-write mode, or exclusive mode. The exclusive mode guarantees that
  88  * nobody else will be able to open this volume. UBI allows to have many volume
  89  * readers and one writer at a time.
  90  *
  91  * If a static volume is being opened for the first time since boot, it will be
  92  * checked by this function, which means it will be fully read and the CRC
  93  * checksum of each logical eraseblock will be checked.
  94  *
  95  * This function returns volume descriptor in case of success and a negative
  96  * error code in case of failure.
  97  */
  98 struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
  99 {
 100         int err;
 101         struct ubi_volume_desc *desc;
 102         struct ubi_device *ubi = ubi_devices[ubi_num];
 103         struct ubi_volume *vol;
 104
 105         dbg_msg("open device %d volume %d, mode %d", ubi_num, vol_id, mode);
 106
 107         err = -ENODEV;
 108         if (!try_module_get(THIS_MODULE))
 109                 return ERR_PTR(err);
 110
 111         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES || !ubi)
 112                 goto out_put;
 113
 114         err = -EINVAL;
 115         if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 116                 goto out_put;
 117         if (mode != UBI_READONLY && mode != UBI_READWRITE &&
 118             mode != UBI_EXCLUSIVE)
 119                 goto out_put;
 120
 121         desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL);
 122         if (!desc) {
 123                 err = -ENOMEM;
 124                 goto out_put;
 125         }
 126
 127         spin_lock(&ubi->volumes_lock);
 128         vol = ubi->volumes[vol_id];
 129         if (!vol) {
 130                 err = -ENODEV;
 131                 goto out_unlock;
 132         }
 133
 134         err = -EBUSY;
 135         switch (mode) {
 136         case UBI_READONLY:
 137                 if (vol->exclusive)
 138                         goto out_unlock;
 139                 vol->readers += 1;
 140                 break;
 141
 142         case UBI_READWRITE:
 143                 if (vol->exclusive || vol->writers > 0)
 144                         goto out_unlock;
 145                 vol->writers += 1;
 146                 break;
 147
 148         case UBI_EXCLUSIVE:
 149                 if (vol->exclusive || vol->writers || vol->readers)
 150                         goto out_unlock;
 151                 vol->exclusive = 1;
 152                 break;
 153         }
 154         spin_unlock(&ubi->volumes_lock);
 155
 156         desc->vol = vol;
 157         desc->mode = mode;
 158
 159         /*
 160          * To prevent simultaneous checks of the same volume we use @vtbl_mutex,
 161          * although it is not the purpose it was introduced for.
 162          */
 163         mutex_lock(&ubi->vtbl_mutex);
 164         if (!vol->checked) {
 165                 /* This is the first open - check the volume */
 166                 err = ubi_check_volume(ubi, vol_id);
 167                 if (err < 0) {
 168                         mutex_unlock(&ubi->vtbl_mutex);
 169                         ubi_close_volume(desc);
 170                         return ERR_PTR(err);
 171                 }
 172                 if (err == 1) {
 173                         ubi_warn("volume %d on UBI device %d is corrupted",
 174                                  vol_id, ubi->ubi_num);
 175                         vol->corrupted = 1;
 176                 }
 177                 vol->checked = 1;
 178         }
 179         mutex_unlock(&ubi->vtbl_mutex);
 180         return desc;
 181
 182 out_unlock:
 183         spin_unlock(&ubi->volumes_lock);
 184         kfree(desc);
 185 out_put:
 186         module_put(THIS_MODULE);
 187         return ERR_PTR(err);
 188 }
 189 EXPORT_SYMBOL_GPL(ubi_open_volume);
 190
 191 /**
 192  * ubi_open_volume_nm - open UBI volume by name.
 193  * @ubi_num: UBI device number
 194  * @name: volume name
 195  * @mode: open mode
 196  *
 197  * This function is similar to 'ubi_open_volume()', but opens a volume by name.
 198  */
 199 struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
 200                                            int mode)
 201 {
 202         int i, vol_id = -1, len;
 203         struct ubi_volume_desc *ret;
 204         struct ubi_device *ubi;
 205
 206         dbg_msg("open volume %s, mode %d", name, mode);
 207
 208         if (!name)
 209                 return ERR_PTR(-EINVAL);
 210
 211         len = strnlen(name, UBI_VOL_NAME_MAX + 1);
 212         if (len > UBI_VOL_NAME_MAX)
 213                 return ERR_PTR(-EINVAL);
 214
 215         ret = ERR_PTR(-ENODEV);
 216         if (!try_module_get(THIS_MODULE))
 217                 return ret;
 218
 219         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES || !ubi_devices[ubi_num])
 220                 goto out_put;
 221
 222         ubi = ubi_devices[ubi_num];
 223
 224         spin_lock(&ubi->volumes_lock);
 225         /* Walk all volumes of this UBI device */
 226         for (i = 0; i < ubi->vtbl_slots; i++) {
 227                 struct ubi_volume *vol = ubi->volumes[i];
 228
 229                 if (vol && len == vol->name_len && !strcmp(name, vol->name)) {
 230                         vol_id = i;
 231                         break;
 232                 }
 233         }
 234         spin_unlock(&ubi->volumes_lock);
 235
 236         if (vol_id < 0)
 237                 goto out_put;
 238
 239         ret = ubi_open_volume(ubi_num, vol_id, mode);
 240
 241 out_put:
 242         module_put(THIS_MODULE);
 243         return ret;
 244 }
 245 EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
 246
 247 /**
 248  * ubi_close_volume - close UBI volume.
 249  * @desc: volume descriptor
 250  */
 251 void ubi_close_volume(struct ubi_volume_desc *desc)
 252 {
 253         struct ubi_volume *vol = desc->vol;
 254
 255         dbg_msg("close volume %d, mode %d", vol->vol_id, desc->mode);
 256
 257         spin_lock(&vol->ubi->volumes_lock);
 258         switch (desc->mode) {
 259         case UBI_READONLY:
 260                 vol->readers -= 1;
 261                 break;
 262         case UBI_READWRITE:
 263                 vol->writers -= 1;
 264                 break;
 265         case UBI_EXCLUSIVE:
 266                 vol->exclusive = 0;
 267         }
 268         spin_unlock(&vol->ubi->volumes_lock);
 269
 270         kfree(desc);
 271         module_put(THIS_MODULE);
 272 }
 273 EXPORT_SYMBOL_GPL(ubi_close_volume);
 274
 275 /**
 276  * ubi_leb_read - read data.
 277  * @desc: volume descriptor
 278  * @lnum: logical eraseblock number to read from
 279  * @buf: buffer where to store the read data
 280  * @offset: offset within the logical eraseblock to read from
 281  * @len: how many bytes to read
 282  * @check: whether UBI has to check the read data's CRC or not.
 283  *
 284  * This function reads data from offset @offset of logical eraseblock @lnum and
 285  * stores the data at @buf. When reading from static volumes, @check specifies
 286  * whether the data has to be checked or not. If yes, the whole logical
 287  * eraseblock will be read and its CRC checksum will be checked (i.e., the CRC
 288  * checksum is per-eraseblock). So checking may substantially slow down the
 289  * read speed. The @check argument is ignored for dynamic volumes.
 290  *
 291  * In case of success, this function returns zero. In case of failure, this
 292  * function returns a negative error code.
 293  *
 294  * %-EBADMSG error code is returned:
 295  * o for both static and dynamic volumes if MTD driver has detected a data
 296  *   integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
 297  * o for static volumes in case of data CRC mismatch.
 298  *
 299  * If the volume is damaged because of an interrupted update this function just
 300  * returns immediately with %-EBADF error code.
 301  */
 302 int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
 303                  int len, int check)
 304 {
 305         struct ubi_volume *vol = desc->vol;
 306         struct ubi_device *ubi = vol->ubi;
 307         int err, vol_id = vol->vol_id;
 308
 309         dbg_msg("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
 310
 311         if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
 312             lnum >= vol->used_ebs || offset < 0 || len < 0 ||
 313             offset + len > vol->usable_leb_size)
 314                 return -EINVAL;
 315
 316         if (vol->vol_type == UBI_STATIC_VOLUME) {
 317                 if (vol->used_ebs == 0)
 318                         /* Empty static UBI volume */
 319                         return 0;
 320                 if (lnum == vol->used_ebs - 1 &&
 321                     offset + len > vol->last_eb_bytes)
 322                         return -EINVAL;
 323         }
 324
 325         if (vol->upd_marker)
 326                 return -EBADF;
 327         if (len == 0)
 328                 return 0;
 329
 330         err = ubi_eba_read_leb(ubi, vol_id, lnum, buf, offset, len, check);
 331         if (err && err == -EBADMSG && vol->vol_type == UBI_STATIC_VOLUME) {
 332                 ubi_warn("mark volume %d as corrupted", vol_id);
 333                 vol->corrupted = 1;
 334         }
 335
 336         return err;
 337 }
 338 EXPORT_SYMBOL_GPL(ubi_leb_read);
 339
 340 /**
 341  * ubi_leb_write - write data.
 342  * @desc: volume descriptor
 343  * @lnum: logical eraseblock number to write to
 344  * @buf: data to write
 345  * @offset: offset within the logical eraseblock where to write
 346  * @len: how many bytes to write
 347  * @dtype: expected data type
 348  *
 349  * This function writes @len bytes of data from @buf to offset @offset of
 350  * logical eraseblock @lnum. The @dtype argument describes expected lifetime of
 351  * the data.
 352  *
 353  * This function takes care of physical eraseblock write failures. If write to
 354  * the physical eraseblock write operation fails, the logical eraseblock is
 355  * re-mapped to another physical eraseblock, the data is recovered, and the
 356  * write finishes. UBI has a pool of reserved physical eraseblocks for this.
 357  *
 358  * If all the data were successfully written, zero is returned. If an error
 359  * occurred and UBI has not been able to recover from it, this function returns
 360  * a negative error code. Note, in case of an error, it is possible that
 361  * something was still written to the flash media, but that may be some
 362  * garbage.
 363  *
 364  * If the volume is damaged because of an interrupted update this function just
 365  * returns immediately with %-EBADF code.
 366  */
 367 int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
 368                   int offset, int len, int dtype)
 369 {
 370         struct ubi_volume *vol = desc->vol;
 371         struct ubi_device *ubi = vol->ubi;
 372         int vol_id = vol->vol_id;
 373
 374         dbg_msg("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);
 375
 376         if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 377                 return -EINVAL;
 378
 379         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 380                 return -EROFS;
 381
 382         if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 ||
 383             offset + len > vol->usable_leb_size || offset % ubi->min_io_size ||
 384             len % ubi->min_io_size)
 385                 return -EINVAL;
 386
 387         if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
 388             dtype != UBI_UNKNOWN)
 389                 return -EINVAL;
 390
 391         if (vol->upd_marker)
 392                 return -EBADF;
 393
 394         if (len == 0)
 395                 return 0;
 396
 397         return ubi_eba_write_leb(ubi, vol_id, lnum, buf, offset, len, dtype);
 398 }
 399 EXPORT_SYMBOL_GPL(ubi_leb_write);
 400
 401 /*
 402  * ubi_leb_change - change logical eraseblock atomically.
 403  * @desc: volume descriptor
 404  * @lnum: logical eraseblock number to change
 405  * @buf: data to write
 406  * @len: how many bytes to write
 407  * @dtype: expected data type
 408  *
 409  * This function changes the contents of a logical eraseblock atomically. @buf
 410  * has to contain new logical eraseblock data, and @len - the length of the
 411  * data, which has to be aligned. The length may be shorter then the logical
 412  * eraseblock size, ant the logical eraseblock may be appended to more times
 413  * later on. This function guarantees that in case of an unclean reboot the old
 414  * contents is preserved. Returns zero in case of success and a negative error
 415  * code in case of failure.
 416  */
 417 int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
 418                    int len, int dtype)
 419 {
 420         struct ubi_volume *vol = desc->vol;
 421         struct ubi_device *ubi = vol->ubi;
 422         int vol_id = vol->vol_id;
 423
 424         dbg_msg("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);
 425
 426         if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 427                 return -EINVAL;
 428
 429         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 430                 return -EROFS;
 431
 432         if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 ||
 433             len > vol->usable_leb_size || len % ubi->min_io_size)
 434                 return -EINVAL;
 435
 436         if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
 437             dtype != UBI_UNKNOWN)
 438                 return -EINVAL;
 439
 440         if (vol->upd_marker)
 441                 return -EBADF;
 442
 443         if (len == 0)
 444                 return 0;
 445
 446         return ubi_eba_atomic_leb_change(ubi, vol_id, lnum, buf, len, dtype);
 447 }
 448 EXPORT_SYMBOL_GPL(ubi_leb_change);
 449
 450 /**
 451  * ubi_leb_erase - erase logical eraseblock.
 452  * @desc: volume descriptor
 453  * @lnum: logical eraseblock number
 454  *
 455  * This function un-maps logical eraseblock @lnum and synchronously erases the
 456  * correspondent physical eraseblock. Returns zero in case of success and a
 457  * negative error code in case of failure.
 458  *
 459  * If the volume is damaged because of an interrupted update this function just
 460  * returns immediately with %-EBADF code.
 461  */
 462 int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
 463 {
 464         struct ubi_volume *vol = desc->vol;
 465         struct ubi_device *ubi = vol->ubi;
 466         int err, vol_id = vol->vol_id;
 467
 468         dbg_msg("erase LEB %d:%d", vol_id, lnum);
 469
 470         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 471                 return -EROFS;
 472
 473         if (lnum < 0 || lnum >= vol->reserved_pebs)
 474                 return -EINVAL;
 475
 476         if (vol->upd_marker)
 477                 return -EBADF;
 478
 479         err = ubi_eba_unmap_leb(ubi, vol_id, lnum);
 480         if (err)
 481                 return err;
 482
 483         return ubi_wl_flush(ubi);
 484 }
 485 EXPORT_SYMBOL_GPL(ubi_leb_erase);
 486
 487 /**
 488  * ubi_leb_unmap - un-map logical eraseblock.
 489  * @desc: volume descriptor
 490  * @lnum: logical eraseblock number
 491  *
 492  * This function un-maps logical eraseblock @lnum and schedules the
 493  * corresponding physical eraseblock for erasure, so that it will eventually be
 494  * physically erased in background. This operation is much faster then the
 495  * erase operation.
 496  *
 497  * Unlike erase, the un-map operation does not guarantee that the logical
 498  * eraseblock will contain all 0xFF bytes when UBI is initialized again. For
 499  * example, if several logical eraseblocks are un-mapped, and an unclean reboot
 500  * happens after this, the logical eraseblocks will not necessarily be
 501  * un-mapped again when this MTD device is attached. They may actually be
 502  * mapped to the same physical eraseblocks again. So, this function has to be
 503  * used with care.
 504  *
 505  * In other words, when un-mapping a logical eraseblock, UBI does not store
 506  * any information about this on the flash media, it just marks the logical
 507  * eraseblock as "un-mapped" in RAM. If UBI is detached before the physical
 508  * eraseblock is physically erased, it will be mapped again to the same logical
 509  * eraseblock when the MTD device is attached again.
 510  *
 511  * The main and obvious use-case of this function is when the contents of a
 512  * logical eraseblock has to be re-written. Then it is much more efficient to
 513  * first un-map it, then write new data, rather then first erase it, then write
 514  * new data. Note, once new data has been written to the logical eraseblock,
 515  * UBI guarantees that the old contents has gone forever. In other words, if an
 516  * unclean reboot happens after the logical eraseblock has been un-mapped and
 517  * then written to, it will contain the last written data.
 518  *
 519  * This function returns zero in case of success and a negative error code in
 520  * case of failure. If the volume is damaged because of an interrupted update
 521  * this function just returns immediately with %-EBADF code.
 522  */
 523 int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
 524 {
 525         struct ubi_volume *vol = desc->vol;
 526         struct ubi_device *ubi = vol->ubi;
 527         int vol_id = vol->vol_id;
 528
 529         dbg_msg("unmap LEB %d:%d", vol_id, lnum);
 530
 531         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 532                 return -EROFS;
 533
 534         if (lnum < 0 || lnum >= vol->reserved_pebs)
 535                 return -EINVAL;
 536
 537         if (vol->upd_marker)
 538                 return -EBADF;
 539
 540         return ubi_eba_unmap_leb(ubi, vol_id, lnum);
 541 }
 542 EXPORT_SYMBOL_GPL(ubi_leb_unmap);
 543
 544 /**
 545  * ubi_is_mapped - check if logical eraseblock is mapped.
 546  * @desc: volume descriptor
 547  * @lnum: logical eraseblock number
 548  *
 549  * This function checks if logical eraseblock @lnum is mapped to a physical
 550  * eraseblock. If a logical eraseblock is un-mapped, this does not necessarily
 551  * mean it will still be un-mapped after the UBI device is re-attached. The
 552  * logical eraseblock may become mapped to the physical eraseblock it was last
 553  * mapped to.
 554  *
 555  * This function returns %1 if the LEB is mapped, %0 if not, and a negative
 556  * error code in case of failure. If the volume is damaged because of an
 557  * interrupted update this function just returns immediately with %-EBADF error
 558  * code.
 559  */
 560 int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum)
 561 {
 562         struct ubi_volume *vol = desc->vol;
 563
 564         dbg_msg("test LEB %d:%d", vol->vol_id, lnum);
 565
 566         if (lnum < 0 || lnum >= vol->reserved_pebs)
 567                 return -EINVAL;
 568
 569         if (vol->upd_marker)
 570                 return -EBADF;
 571
 572         return vol->eba_tbl[lnum] >= 0;
 573 }
 574 EXPORT_SYMBOL_GPL(ubi_is_mapped);