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