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;
 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 (ubi_num < 0)
 109                 return ERR_PTR(err);
 110
 111         ubi = ubi_devices[ubi_num];
 112
 113         if (!try_module_get(THIS_MODULE))
 114                 return ERR_PTR(err);
 115
 116         if (ubi_num >= UBI_MAX_DEVICES || !ubi)
 117                 goto out_put;
 118
 119         err = -EINVAL;
 120         if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 121                 goto out_put;
 122         if (mode != UBI_READONLY && mode != UBI_READWRITE &&
 123             mode != UBI_EXCLUSIVE)
 124                 goto out_put;
 125
 126         desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL);
 127         if (!desc) {
 128                 err = -ENOMEM;
 129                 goto out_put;
 130         }
 131
 132         spin_lock(&ubi->volumes_lock);
 133         vol = ubi->volumes[vol_id];
 134         if (!vol) {
 135                 err = -ENODEV;
 136                 goto out_unlock;
 137         }
 138
 139         err = -EBUSY;
 140         switch (mode) {
 141         case UBI_READONLY:
 142                 if (vol->exclusive)
 143                         goto out_unlock;
 144                 vol->readers += 1;
 145                 break;
 146
 147         case UBI_READWRITE:
 148                 if (vol->exclusive || vol->writers > 0)
 149                         goto out_unlock;
 150                 vol->writers += 1;
 151                 break;
 152
 153         case UBI_EXCLUSIVE:
 154                 if (vol->exclusive || vol->writers || vol->readers)
 155                         goto out_unlock;
 156                 vol->exclusive = 1;
 157                 break;
 158         }
 159         spin_unlock(&ubi->volumes_lock);
 160
 161         desc->vol = vol;
 162         desc->mode = mode;
 163
 164         /*
 165          * To prevent simultaneous checks of the same volume we use @vtbl_mutex,
 166          * although it is not the purpose it was introduced for.
 167          */
 168         mutex_lock(&ubi->vtbl_mutex);
 169         if (!vol->checked) {
 170                 /* This is the first open - check the volume */
 171                 err = ubi_check_volume(ubi, vol_id);
 172                 if (err < 0) {
 173                         mutex_unlock(&ubi->vtbl_mutex);
 174                         ubi_close_volume(desc);
 175                         return ERR_PTR(err);
 176                 }
 177                 if (err == 1) {
 178                         ubi_warn("volume %d on UBI device %d is corrupted",
 179                                  vol_id, ubi->ubi_num);
 180                         vol->corrupted = 1;
 181                 }
 182                 vol->checked = 1;
 183         }
 184         mutex_unlock(&ubi->vtbl_mutex);
 185         return desc;
 186
 187 out_unlock:
 188         spin_unlock(&ubi->volumes_lock);
 189         kfree(desc);
 190 out_put:
 191         module_put(THIS_MODULE);
 192         return ERR_PTR(err);
 193 }
 194 EXPORT_SYMBOL_GPL(ubi_open_volume);
 195
 196 /**
 197  * ubi_open_volume_nm - open UBI volume by name.
 198  * @ubi_num: UBI device number
 199  * @name: volume name
 200  * @mode: open mode
 201  *
 202  * This function is similar to 'ubi_open_volume()', but opens a volume by name.
 203  */
 204 struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
 205                                            int mode)
 206 {
 207         int i, vol_id = -1, len;
 208         struct ubi_volume_desc *ret;
 209         struct ubi_device *ubi;
 210
 211         dbg_msg("open volume %s, mode %d", name, mode);
 212
 213         if (!name)
 214                 return ERR_PTR(-EINVAL);
 215
 216         len = strnlen(name, UBI_VOL_NAME_MAX + 1);
 217         if (len > UBI_VOL_NAME_MAX)
 218                 return ERR_PTR(-EINVAL);
 219
 220         ret = ERR_PTR(-ENODEV);
 221         if (!try_module_get(THIS_MODULE))
 222                 return ret;
 223
 224         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES || !ubi_devices[ubi_num])
 225                 goto out_put;
 226
 227         ubi = ubi_devices[ubi_num];
 228
 229         spin_lock(&ubi->volumes_lock);
 230         /* Walk all volumes of this UBI device */
 231         for (i = 0; i < ubi->vtbl_slots; i++) {
 232                 struct ubi_volume *vol = ubi->volumes[i];
 233
 234                 if (vol && len == vol->name_len && !strcmp(name, vol->name)) {
 235                         vol_id = i;
 236                         break;
 237                 }
 238         }
 239         spin_unlock(&ubi->volumes_lock);
 240
 241         if (vol_id < 0)
 242                 goto out_put;
 243
 244         ret = ubi_open_volume(ubi_num, vol_id, mode);
 245
 246 out_put:
 247         module_put(THIS_MODULE);
 248         return ret;
 249 }
 250 EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
 251
 252 /**
 253  * ubi_close_volume - close UBI volume.
 254  * @desc: volume descriptor
 255  */
 256 void ubi_close_volume(struct ubi_volume_desc *desc)
 257 {
 258         struct ubi_volume *vol = desc->vol;
 259
 260         dbg_msg("close volume %d, mode %d", vol->vol_id, desc->mode);
 261
 262         spin_lock(&vol->ubi->volumes_lock);
 263         switch (desc->mode) {
 264         case UBI_READONLY:
 265                 vol->readers -= 1;
 266                 break;
 267         case UBI_READWRITE:
 268                 vol->writers -= 1;
 269                 break;
 270         case UBI_EXCLUSIVE:
 271                 vol->exclusive = 0;
 272         }
 273         spin_unlock(&vol->ubi->volumes_lock);
 274
 275         kfree(desc);
 276         module_put(THIS_MODULE);
 277 }
 278 EXPORT_SYMBOL_GPL(ubi_close_volume);
 279
 280 /**
 281  * ubi_leb_read - read data.
 282  * @desc: volume descriptor
 283  * @lnum: logical eraseblock number to read from
 284  * @buf: buffer where to store the read data
 285  * @offset: offset within the logical eraseblock to read from
 286  * @len: how many bytes to read
 287  * @check: whether UBI has to check the read data's CRC or not.
 288  *
 289  * This function reads data from offset @offset of logical eraseblock @lnum and
 290  * stores the data at @buf. When reading from static volumes, @check specifies
 291  * whether the data has to be checked or not. If yes, the whole logical
 292  * eraseblock will be read and its CRC checksum will be checked (i.e., the CRC
 293  * checksum is per-eraseblock). So checking may substantially slow down the
 294  * read speed. The @check argument is ignored for dynamic volumes.
 295  *
 296  * In case of success, this function returns zero. In case of failure, this
 297  * function returns a negative error code.
 298  *
 299  * %-EBADMSG error code is returned:
 300  * o for both static and dynamic volumes if MTD driver has detected a data
 301  *   integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
 302  * o for static volumes in case of data CRC mismatch.
 303  *
 304  * If the volume is damaged because of an interrupted update this function just
 305  * returns immediately with %-EBADF error code.
 306  */
 307 int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
 308                  int len, int check)
 309 {
 310         struct ubi_volume *vol = desc->vol;
 311         struct ubi_device *ubi = vol->ubi;
 312         int err, vol_id = vol->vol_id;
 313
 314         dbg_msg("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
 315
 316         if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
 317             lnum >= vol->used_ebs || offset < 0 || len < 0 ||
 318             offset + len > vol->usable_leb_size)
 319                 return -EINVAL;
 320
 321         if (vol->vol_type == UBI_STATIC_VOLUME) {
 322                 if (vol->used_ebs == 0)
 323                         /* Empty static UBI volume */
 324                         return 0;
 325                 if (lnum == vol->used_ebs - 1 &&
 326                     offset + len > vol->last_eb_bytes)
 327                         return -EINVAL;
 328         }
 329
 330         if (vol->upd_marker)
 331                 return -EBADF;
 332         if (len == 0)
 333                 return 0;
 334
 335         err = ubi_eba_read_leb(ubi, vol_id, lnum, buf, offset, len, check);
 336         if (err && err == -EBADMSG && vol->vol_type == UBI_STATIC_VOLUME) {
 337                 ubi_warn("mark volume %d as corrupted", vol_id);
 338                 vol->corrupted = 1;
 339         }
 340
 341         return err;
 342 }
 343 EXPORT_SYMBOL_GPL(ubi_leb_read);
 344
 345 /**
 346  * ubi_leb_write - write data.
 347  * @desc: volume descriptor
 348  * @lnum: logical eraseblock number to write to
 349  * @buf: data to write
 350  * @offset: offset within the logical eraseblock where to write
 351  * @len: how many bytes to write
 352  * @dtype: expected data type
 353  *
 354  * This function writes @len bytes of data from @buf to offset @offset of
 355  * logical eraseblock @lnum. The @dtype argument describes expected lifetime of
 356  * the data.
 357  *
 358  * This function takes care of physical eraseblock write failures. If write to
 359  * the physical eraseblock write operation fails, the logical eraseblock is
 360  * re-mapped to another physical eraseblock, the data is recovered, and the
 361  * write finishes. UBI has a pool of reserved physical eraseblocks for this.
 362  *
 363  * If all the data were successfully written, zero is returned. If an error
 364  * occurred and UBI has not been able to recover from it, this function returns
 365  * a negative error code. Note, in case of an error, it is possible that
 366  * something was still written to the flash media, but that may be some
 367  * garbage.
 368  *
 369  * If the volume is damaged because of an interrupted update this function just
 370  * returns immediately with %-EBADF code.
 371  */
 372 int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
 373                   int offset, int len, int dtype)
 374 {
 375         struct ubi_volume *vol = desc->vol;
 376         struct ubi_device *ubi = vol->ubi;
 377         int vol_id = vol->vol_id;
 378
 379         dbg_msg("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);
 380
 381         if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 382                 return -EINVAL;
 383
 384         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 385                 return -EROFS;
 386
 387         if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 ||
 388             offset + len > vol->usable_leb_size || offset % ubi->min_io_size ||
 389             len % ubi->min_io_size)
 390                 return -EINVAL;
 391
 392         if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
 393             dtype != UBI_UNKNOWN)
 394                 return -EINVAL;
 395
 396         if (vol->upd_marker)
 397                 return -EBADF;
 398
 399         if (len == 0)
 400                 return 0;
 401
 402         return ubi_eba_write_leb(ubi, vol_id, lnum, buf, offset, len, dtype);
 403 }
 404 EXPORT_SYMBOL_GPL(ubi_leb_write);
 405
 406 /*
 407  * ubi_leb_change - change logical eraseblock atomically.
 408  * @desc: volume descriptor
 409  * @lnum: logical eraseblock number to change
 410  * @buf: data to write
 411  * @len: how many bytes to write
 412  * @dtype: expected data type
 413  *
 414  * This function changes the contents of a logical eraseblock atomically. @buf
 415  * has to contain new logical eraseblock data, and @len - the length of the
 416  * data, which has to be aligned. The length may be shorter then the logical
 417  * eraseblock size, ant the logical eraseblock may be appended to more times
 418  * later on. This function guarantees that in case of an unclean reboot the old
 419  * contents is preserved. Returns zero in case of success and a negative error
 420  * code in case of failure.
 421  */
 422 int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
 423                    int len, int dtype)
 424 {
 425         struct ubi_volume *vol = desc->vol;
 426         struct ubi_device *ubi = vol->ubi;
 427         int vol_id = vol->vol_id;
 428
 429         dbg_msg("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);
 430
 431         if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 432                 return -EINVAL;
 433
 434         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 435                 return -EROFS;
 436
 437         if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 ||
 438             len > vol->usable_leb_size || len % ubi->min_io_size)
 439                 return -EINVAL;
 440
 441         if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
 442             dtype != UBI_UNKNOWN)
 443                 return -EINVAL;
 444
 445         if (vol->upd_marker)
 446                 return -EBADF;
 447
 448         if (len == 0)
 449                 return 0;
 450
 451         return ubi_eba_atomic_leb_change(ubi, vol_id, lnum, buf, len, dtype);
 452 }
 453 EXPORT_SYMBOL_GPL(ubi_leb_change);
 454
 455 /**
 456  * ubi_leb_erase - erase logical eraseblock.
 457  * @desc: volume descriptor
 458  * @lnum: logical eraseblock number
 459  *
 460  * This function un-maps logical eraseblock @lnum and synchronously erases the
 461  * correspondent physical eraseblock. Returns zero in case of success and a
 462  * negative error code in case of failure.
 463  *
 464  * If the volume is damaged because of an interrupted update this function just
 465  * returns immediately with %-EBADF code.
 466  */
 467 int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
 468 {
 469         struct ubi_volume *vol = desc->vol;
 470         struct ubi_device *ubi = vol->ubi;
 471         int err, vol_id = vol->vol_id;
 472
 473         dbg_msg("erase LEB %d:%d", vol_id, lnum);
 474
 475         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 476                 return -EROFS;
 477
 478         if (lnum < 0 || lnum >= vol->reserved_pebs)
 479                 return -EINVAL;
 480
 481         if (vol->upd_marker)
 482                 return -EBADF;
 483
 484         err = ubi_eba_unmap_leb(ubi, vol_id, lnum);
 485         if (err)
 486                 return err;
 487
 488         return ubi_wl_flush(ubi);
 489 }
 490 EXPORT_SYMBOL_GPL(ubi_leb_erase);
 491
 492 /**
 493  * ubi_leb_unmap - un-map logical eraseblock.
 494  * @desc: volume descriptor
 495  * @lnum: logical eraseblock number
 496  *
 497  * This function un-maps logical eraseblock @lnum and schedules the
 498  * corresponding physical eraseblock for erasure, so that it will eventually be
 499  * physically erased in background. This operation is much faster then the
 500  * erase operation.
 501  *
 502  * Unlike erase, the un-map operation does not guarantee that the logical
 503  * eraseblock will contain all 0xFF bytes when UBI is initialized again. For
 504  * example, if several logical eraseblocks are un-mapped, and an unclean reboot
 505  * happens after this, the logical eraseblocks will not necessarily be
 506  * un-mapped again when this MTD device is attached. They may actually be
 507  * mapped to the same physical eraseblocks again. So, this function has to be
 508  * used with care.
 509  *
 510  * In other words, when un-mapping a logical eraseblock, UBI does not store
 511  * any information about this on the flash media, it just marks the logical
 512  * eraseblock as "un-mapped" in RAM. If UBI is detached before the physical
 513  * eraseblock is physically erased, it will be mapped again to the same logical
 514  * eraseblock when the MTD device is attached again.
 515  *
 516  * The main and obvious use-case of this function is when the contents of a
 517  * logical eraseblock has to be re-written. Then it is much more efficient to
 518  * first un-map it, then write new data, rather then first erase it, then write
 519  * new data. Note, once new data has been written to the logical eraseblock,
 520  * UBI guarantees that the old contents has gone forever. In other words, if an
 521  * unclean reboot happens after the logical eraseblock has been un-mapped and
 522  * then written to, it will contain the last written data.
 523  *
 524  * This function returns zero in case of success and a negative error code in
 525  * case of failure. If the volume is damaged because of an interrupted update
 526  * this function just returns immediately with %-EBADF code.
 527  */
 528 int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
 529 {
 530         struct ubi_volume *vol = desc->vol;
 531         struct ubi_device *ubi = vol->ubi;
 532         int vol_id = vol->vol_id;
 533
 534         dbg_msg("unmap LEB %d:%d", vol_id, lnum);
 535
 536         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 537                 return -EROFS;
 538
 539         if (lnum < 0 || lnum >= vol->reserved_pebs)
 540                 return -EINVAL;
 541
 542         if (vol->upd_marker)
 543                 return -EBADF;
 544
 545         return ubi_eba_unmap_leb(ubi, vol_id, lnum);
 546 }
 547 EXPORT_SYMBOL_GPL(ubi_leb_unmap);
 548
 549 /**
 550  * ubi_is_mapped - check if logical eraseblock is mapped.
 551  * @desc: volume descriptor
 552  * @lnum: logical eraseblock number
 553  *
 554  * This function checks if logical eraseblock @lnum is mapped to a physical
 555  * eraseblock. If a logical eraseblock is un-mapped, this does not necessarily
 556  * mean it will still be un-mapped after the UBI device is re-attached. The
 557  * logical eraseblock may become mapped to the physical eraseblock it was last
 558  * mapped to.
 559  *
 560  * This function returns %1 if the LEB is mapped, %0 if not, and a negative
 561  * error code in case of failure. If the volume is damaged because of an
 562  * interrupted update this function just returns immediately with %-EBADF error
 563  * code.
 564  */
 565 int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum)
 566 {
 567         struct ubi_volume *vol = desc->vol;
 568
 569         dbg_msg("test LEB %d:%d", vol->vol_id, lnum);
 570
 571         if (lnum < 0 || lnum >= vol->reserved_pebs)
 572                 return -EINVAL;
 573
 574         if (vol->upd_marker)
 575                 return -EBADF;
 576
 577         return vol->eba_tbl[lnum] >= 0;
 578 }
 579 EXPORT_SYMBOL_GPL(ubi_is_mapped);