linux/drivers/mtd/mtdcore.c
<<
>>
Prefs
   1/*
   2 * Core registration and callback routines for MTD
   3 * drivers and users.
   4 *
   5 * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
   6 * Copyright © 2006      Red Hat UK Limited 
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; either version 2 of the License, or
  11 * (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  21 *
  22 */
  23
  24#include <linux/module.h>
  25#include <linux/kernel.h>
  26#include <linux/ptrace.h>
  27#include <linux/seq_file.h>
  28#include <linux/string.h>
  29#include <linux/timer.h>
  30#include <linux/major.h>
  31#include <linux/fs.h>
  32#include <linux/err.h>
  33#include <linux/ioctl.h>
  34#include <linux/init.h>
  35#include <linux/proc_fs.h>
  36#include <linux/idr.h>
  37#include <linux/backing-dev.h>
  38#include <linux/gfp.h>
  39#include <linux/slab.h>
  40
  41#include <linux/mtd/mtd.h>
  42#include <linux/mtd/partitions.h>
  43
  44#include "mtdcore.h"
  45
  46/*
  47 * backing device capabilities for non-mappable devices (such as NAND flash)
  48 * - permits private mappings, copies are taken of the data
  49 */
  50static struct backing_dev_info mtd_bdi_unmappable = {
  51        .capabilities   = BDI_CAP_MAP_COPY,
  52};
  53
  54/*
  55 * backing device capabilities for R/O mappable devices (such as ROM)
  56 * - permits private mappings, copies are taken of the data
  57 * - permits non-writable shared mappings
  58 */
  59static struct backing_dev_info mtd_bdi_ro_mappable = {
  60        .capabilities   = (BDI_CAP_MAP_COPY | BDI_CAP_MAP_DIRECT |
  61                           BDI_CAP_EXEC_MAP | BDI_CAP_READ_MAP),
  62};
  63
  64/*
  65 * backing device capabilities for writable mappable devices (such as RAM)
  66 * - permits private mappings, copies are taken of the data
  67 * - permits non-writable shared mappings
  68 */
  69static struct backing_dev_info mtd_bdi_rw_mappable = {
  70        .capabilities   = (BDI_CAP_MAP_COPY | BDI_CAP_MAP_DIRECT |
  71                           BDI_CAP_EXEC_MAP | BDI_CAP_READ_MAP |
  72                           BDI_CAP_WRITE_MAP),
  73};
  74
  75static int mtd_cls_suspend(struct device *dev, pm_message_t state);
  76static int mtd_cls_resume(struct device *dev);
  77
  78static struct class mtd_class = {
  79        .name = "mtd",
  80        .owner = THIS_MODULE,
  81        .suspend = mtd_cls_suspend,
  82        .resume = mtd_cls_resume,
  83};
  84
  85static DEFINE_IDR(mtd_idr);
  86
  87/* These are exported solely for the purpose of mtd_blkdevs.c. You
  88   should not use them for _anything_ else */
  89DEFINE_MUTEX(mtd_table_mutex);
  90EXPORT_SYMBOL_GPL(mtd_table_mutex);
  91
  92struct mtd_info *__mtd_next_device(int i)
  93{
  94        return idr_get_next(&mtd_idr, &i);
  95}
  96EXPORT_SYMBOL_GPL(__mtd_next_device);
  97
  98static LIST_HEAD(mtd_notifiers);
  99
 100
 101#define MTD_DEVT(index) MKDEV(MTD_CHAR_MAJOR, (index)*2)
 102
 103/* REVISIT once MTD uses the driver model better, whoever allocates
 104 * the mtd_info will probably want to use the release() hook...
 105 */
 106static void mtd_release(struct device *dev)
 107{
 108        struct mtd_info __maybe_unused *mtd = dev_get_drvdata(dev);
 109        dev_t index = MTD_DEVT(mtd->index);
 110
 111        /* remove /dev/mtdXro node if needed */
 112        if (index)
 113                device_destroy(&mtd_class, index + 1);
 114}
 115
 116static int mtd_cls_suspend(struct device *dev, pm_message_t state)
 117{
 118        struct mtd_info *mtd = dev_get_drvdata(dev);
 119
 120        return mtd ? mtd_suspend(mtd) : 0;
 121}
 122
 123static int mtd_cls_resume(struct device *dev)
 124{
 125        struct mtd_info *mtd = dev_get_drvdata(dev);
 126
 127        if (mtd)
 128                mtd_resume(mtd);
 129        return 0;
 130}
 131
 132static ssize_t mtd_type_show(struct device *dev,
 133                struct device_attribute *attr, char *buf)
 134{
 135        struct mtd_info *mtd = dev_get_drvdata(dev);
 136        char *type;
 137
 138        switch (mtd->type) {
 139        case MTD_ABSENT:
 140                type = "absent";
 141                break;
 142        case MTD_RAM:
 143                type = "ram";
 144                break;
 145        case MTD_ROM:
 146                type = "rom";
 147                break;
 148        case MTD_NORFLASH:
 149                type = "nor";
 150                break;
 151        case MTD_NANDFLASH:
 152                type = "nand";
 153                break;
 154        case MTD_DATAFLASH:
 155                type = "dataflash";
 156                break;
 157        case MTD_UBIVOLUME:
 158                type = "ubi";
 159                break;
 160        default:
 161                type = "unknown";
 162        }
 163
 164        return snprintf(buf, PAGE_SIZE, "%s\n", type);
 165}
 166static DEVICE_ATTR(type, S_IRUGO, mtd_type_show, NULL);
 167
 168static ssize_t mtd_flags_show(struct device *dev,
 169                struct device_attribute *attr, char *buf)
 170{
 171        struct mtd_info *mtd = dev_get_drvdata(dev);
 172
 173        return snprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)mtd->flags);
 174
 175}
 176static DEVICE_ATTR(flags, S_IRUGO, mtd_flags_show, NULL);
 177
 178static ssize_t mtd_size_show(struct device *dev,
 179                struct device_attribute *attr, char *buf)
 180{
 181        struct mtd_info *mtd = dev_get_drvdata(dev);
 182
 183        return snprintf(buf, PAGE_SIZE, "%llu\n",
 184                (unsigned long long)mtd->size);
 185
 186}
 187static DEVICE_ATTR(size, S_IRUGO, mtd_size_show, NULL);
 188
 189static ssize_t mtd_erasesize_show(struct device *dev,
 190                struct device_attribute *attr, char *buf)
 191{
 192        struct mtd_info *mtd = dev_get_drvdata(dev);
 193
 194        return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->erasesize);
 195
 196}
 197static DEVICE_ATTR(erasesize, S_IRUGO, mtd_erasesize_show, NULL);
 198
 199static ssize_t mtd_writesize_show(struct device *dev,
 200                struct device_attribute *attr, char *buf)
 201{
 202        struct mtd_info *mtd = dev_get_drvdata(dev);
 203
 204        return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->writesize);
 205
 206}
 207static DEVICE_ATTR(writesize, S_IRUGO, mtd_writesize_show, NULL);
 208
 209static ssize_t mtd_subpagesize_show(struct device *dev,
 210                struct device_attribute *attr, char *buf)
 211{
 212        struct mtd_info *mtd = dev_get_drvdata(dev);
 213        unsigned int subpagesize = mtd->writesize >> mtd->subpage_sft;
 214
 215        return snprintf(buf, PAGE_SIZE, "%u\n", subpagesize);
 216
 217}
 218static DEVICE_ATTR(subpagesize, S_IRUGO, mtd_subpagesize_show, NULL);
 219
 220static ssize_t mtd_oobsize_show(struct device *dev,
 221                struct device_attribute *attr, char *buf)
 222{
 223        struct mtd_info *mtd = dev_get_drvdata(dev);
 224
 225        return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->oobsize);
 226
 227}
 228static DEVICE_ATTR(oobsize, S_IRUGO, mtd_oobsize_show, NULL);
 229
 230static ssize_t mtd_numeraseregions_show(struct device *dev,
 231                struct device_attribute *attr, char *buf)
 232{
 233        struct mtd_info *mtd = dev_get_drvdata(dev);
 234
 235        return snprintf(buf, PAGE_SIZE, "%u\n", mtd->numeraseregions);
 236
 237}
 238static DEVICE_ATTR(numeraseregions, S_IRUGO, mtd_numeraseregions_show,
 239        NULL);
 240
 241static ssize_t mtd_name_show(struct device *dev,
 242                struct device_attribute *attr, char *buf)
 243{
 244        struct mtd_info *mtd = dev_get_drvdata(dev);
 245
 246        return snprintf(buf, PAGE_SIZE, "%s\n", mtd->name);
 247
 248}
 249static DEVICE_ATTR(name, S_IRUGO, mtd_name_show, NULL);
 250
 251static ssize_t mtd_ecc_strength_show(struct device *dev,
 252                                     struct device_attribute *attr, char *buf)
 253{
 254        struct mtd_info *mtd = dev_get_drvdata(dev);
 255
 256        return snprintf(buf, PAGE_SIZE, "%u\n", mtd->ecc_strength);
 257}
 258static DEVICE_ATTR(ecc_strength, S_IRUGO, mtd_ecc_strength_show, NULL);
 259
 260static ssize_t mtd_bitflip_threshold_show(struct device *dev,
 261                                          struct device_attribute *attr,
 262                                          char *buf)
 263{
 264        struct mtd_info *mtd = dev_get_drvdata(dev);
 265
 266        return snprintf(buf, PAGE_SIZE, "%u\n", mtd->bitflip_threshold);
 267}
 268
 269static ssize_t mtd_bitflip_threshold_store(struct device *dev,
 270                                           struct device_attribute *attr,
 271                                           const char *buf, size_t count)
 272{
 273        struct mtd_info *mtd = dev_get_drvdata(dev);
 274        unsigned int bitflip_threshold;
 275        int retval;
 276
 277        retval = kstrtouint(buf, 0, &bitflip_threshold);
 278        if (retval)
 279                return retval;
 280
 281        mtd->bitflip_threshold = bitflip_threshold;
 282        return count;
 283}
 284static DEVICE_ATTR(bitflip_threshold, S_IRUGO | S_IWUSR,
 285                   mtd_bitflip_threshold_show,
 286                   mtd_bitflip_threshold_store);
 287
 288static struct attribute *mtd_attrs[] = {
 289        &dev_attr_type.attr,
 290        &dev_attr_flags.attr,
 291        &dev_attr_size.attr,
 292        &dev_attr_erasesize.attr,
 293        &dev_attr_writesize.attr,
 294        &dev_attr_subpagesize.attr,
 295        &dev_attr_oobsize.attr,
 296        &dev_attr_numeraseregions.attr,
 297        &dev_attr_name.attr,
 298        &dev_attr_ecc_strength.attr,
 299        &dev_attr_bitflip_threshold.attr,
 300        NULL,
 301};
 302
 303static struct attribute_group mtd_group = {
 304        .attrs          = mtd_attrs,
 305};
 306
 307static const struct attribute_group *mtd_groups[] = {
 308        &mtd_group,
 309        NULL,
 310};
 311
 312static struct device_type mtd_devtype = {
 313        .name           = "mtd",
 314        .groups         = mtd_groups,
 315        .release        = mtd_release,
 316};
 317
 318/**
 319 *      add_mtd_device - register an MTD device
 320 *      @mtd: pointer to new MTD device info structure
 321 *
 322 *      Add a device to the list of MTD devices present in the system, and
 323 *      notify each currently active MTD 'user' of its arrival. Returns
 324 *      zero on success or 1 on failure, which currently will only happen
 325 *      if there is insufficient memory or a sysfs error.
 326 */
 327
 328int add_mtd_device(struct mtd_info *mtd)
 329{
 330        struct mtd_notifier *not;
 331        int i, error;
 332
 333        if (!mtd->backing_dev_info) {
 334                switch (mtd->type) {
 335                case MTD_RAM:
 336                        mtd->backing_dev_info = &mtd_bdi_rw_mappable;
 337                        break;
 338                case MTD_ROM:
 339                        mtd->backing_dev_info = &mtd_bdi_ro_mappable;
 340                        break;
 341                default:
 342                        mtd->backing_dev_info = &mtd_bdi_unmappable;
 343                        break;
 344                }
 345        }
 346
 347        BUG_ON(mtd->writesize == 0);
 348        mutex_lock(&mtd_table_mutex);
 349
 350        i = idr_alloc(&mtd_idr, mtd, 0, 0, GFP_KERNEL);
 351        if (i < 0)
 352                goto fail_locked;
 353
 354        mtd->index = i;
 355        mtd->usecount = 0;
 356
 357        /* default value if not set by driver */
 358        if (mtd->bitflip_threshold == 0)
 359                mtd->bitflip_threshold = mtd->ecc_strength;
 360
 361        if (is_power_of_2(mtd->erasesize))
 362                mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
 363        else
 364                mtd->erasesize_shift = 0;
 365
 366        if (is_power_of_2(mtd->writesize))
 367                mtd->writesize_shift = ffs(mtd->writesize) - 1;
 368        else
 369                mtd->writesize_shift = 0;
 370
 371        mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
 372        mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
 373
 374        /* Some chips always power up locked. Unlock them now */
 375        if ((mtd->flags & MTD_WRITEABLE) && (mtd->flags & MTD_POWERUP_LOCK)) {
 376                error = mtd_unlock(mtd, 0, mtd->size);
 377                if (error && error != -EOPNOTSUPP)
 378                        printk(KERN_WARNING
 379                               "%s: unlock failed, writes may not work\n",
 380                               mtd->name);
 381        }
 382
 383        /* Caller should have set dev.parent to match the
 384         * physical device.
 385         */
 386        mtd->dev.type = &mtd_devtype;
 387        mtd->dev.class = &mtd_class;
 388        mtd->dev.devt = MTD_DEVT(i);
 389        dev_set_name(&mtd->dev, "mtd%d", i);
 390        dev_set_drvdata(&mtd->dev, mtd);
 391        if (device_register(&mtd->dev) != 0)
 392                goto fail_added;
 393
 394        if (MTD_DEVT(i))
 395                device_create(&mtd_class, mtd->dev.parent,
 396                              MTD_DEVT(i) + 1,
 397                              NULL, "mtd%dro", i);
 398
 399        pr_debug("mtd: Giving out device %d to %s\n", i, mtd->name);
 400        /* No need to get a refcount on the module containing
 401           the notifier, since we hold the mtd_table_mutex */
 402        list_for_each_entry(not, &mtd_notifiers, list)
 403                not->add(mtd);
 404
 405        mutex_unlock(&mtd_table_mutex);
 406        /* We _know_ we aren't being removed, because
 407           our caller is still holding us here. So none
 408           of this try_ nonsense, and no bitching about it
 409           either. :) */
 410        __module_get(THIS_MODULE);
 411        return 0;
 412
 413fail_added:
 414        idr_remove(&mtd_idr, i);
 415fail_locked:
 416        mutex_unlock(&mtd_table_mutex);
 417        return 1;
 418}
 419
 420/**
 421 *      del_mtd_device - unregister an MTD device
 422 *      @mtd: pointer to MTD device info structure
 423 *
 424 *      Remove a device from the list of MTD devices present in the system,
 425 *      and notify each currently active MTD 'user' of its departure.
 426 *      Returns zero on success or 1 on failure, which currently will happen
 427 *      if the requested device does not appear to be present in the list.
 428 */
 429
 430int del_mtd_device(struct mtd_info *mtd)
 431{
 432        int ret;
 433        struct mtd_notifier *not;
 434
 435        mutex_lock(&mtd_table_mutex);
 436
 437        if (idr_find(&mtd_idr, mtd->index) != mtd) {
 438                ret = -ENODEV;
 439                goto out_error;
 440        }
 441
 442        /* No need to get a refcount on the module containing
 443                the notifier, since we hold the mtd_table_mutex */
 444        list_for_each_entry(not, &mtd_notifiers, list)
 445                not->remove(mtd);
 446
 447        if (mtd->usecount) {
 448                printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
 449                       mtd->index, mtd->name, mtd->usecount);
 450                ret = -EBUSY;
 451        } else {
 452                device_unregister(&mtd->dev);
 453
 454                idr_remove(&mtd_idr, mtd->index);
 455
 456                module_put(THIS_MODULE);
 457                ret = 0;
 458        }
 459
 460out_error:
 461        mutex_unlock(&mtd_table_mutex);
 462        return ret;
 463}
 464
 465/**
 466 * mtd_device_parse_register - parse partitions and register an MTD device.
 467 *
 468 * @mtd: the MTD device to register
 469 * @types: the list of MTD partition probes to try, see
 470 *         'parse_mtd_partitions()' for more information
 471 * @parser_data: MTD partition parser-specific data
 472 * @parts: fallback partition information to register, if parsing fails;
 473 *         only valid if %nr_parts > %0
 474 * @nr_parts: the number of partitions in parts, if zero then the full
 475 *            MTD device is registered if no partition info is found
 476 *
 477 * This function aggregates MTD partitions parsing (done by
 478 * 'parse_mtd_partitions()') and MTD device and partitions registering. It
 479 * basically follows the most common pattern found in many MTD drivers:
 480 *
 481 * * It first tries to probe partitions on MTD device @mtd using parsers
 482 *   specified in @types (if @types is %NULL, then the default list of parsers
 483 *   is used, see 'parse_mtd_partitions()' for more information). If none are
 484 *   found this functions tries to fallback to information specified in
 485 *   @parts/@nr_parts.
 486 * * If any partitioning info was found, this function registers the found
 487 *   partitions.
 488 * * If no partitions were found this function just registers the MTD device
 489 *   @mtd and exits.
 490 *
 491 * Returns zero in case of success and a negative error code in case of failure.
 492 */
 493int mtd_device_parse_register(struct mtd_info *mtd, const char * const *types,
 494                              struct mtd_part_parser_data *parser_data,
 495                              const struct mtd_partition *parts,
 496                              int nr_parts)
 497{
 498        int err;
 499        struct mtd_partition *real_parts;
 500
 501        err = parse_mtd_partitions(mtd, types, &real_parts, parser_data);
 502        if (err <= 0 && nr_parts && parts) {
 503                real_parts = kmemdup(parts, sizeof(*parts) * nr_parts,
 504                                     GFP_KERNEL);
 505                if (!real_parts)
 506                        err = -ENOMEM;
 507                else
 508                        err = nr_parts;
 509        }
 510
 511        if (err > 0) {
 512                err = add_mtd_partitions(mtd, real_parts, err);
 513                kfree(real_parts);
 514        } else if (err == 0) {
 515                err = add_mtd_device(mtd);
 516                if (err == 1)
 517                        err = -ENODEV;
 518        }
 519
 520        return err;
 521}
 522EXPORT_SYMBOL_GPL(mtd_device_parse_register);
 523
 524/**
 525 * mtd_device_unregister - unregister an existing MTD device.
 526 *
 527 * @master: the MTD device to unregister.  This will unregister both the master
 528 *          and any partitions if registered.
 529 */
 530int mtd_device_unregister(struct mtd_info *master)
 531{
 532        int err;
 533
 534        err = del_mtd_partitions(master);
 535        if (err)
 536                return err;
 537
 538        if (!device_is_registered(&master->dev))
 539                return 0;
 540
 541        return del_mtd_device(master);
 542}
 543EXPORT_SYMBOL_GPL(mtd_device_unregister);
 544
 545/**
 546 *      register_mtd_user - register a 'user' of MTD devices.
 547 *      @new: pointer to notifier info structure
 548 *
 549 *      Registers a pair of callbacks function to be called upon addition
 550 *      or removal of MTD devices. Causes the 'add' callback to be immediately
 551 *      invoked for each MTD device currently present in the system.
 552 */
 553void register_mtd_user (struct mtd_notifier *new)
 554{
 555        struct mtd_info *mtd;
 556
 557        mutex_lock(&mtd_table_mutex);
 558
 559        list_add(&new->list, &mtd_notifiers);
 560
 561        __module_get(THIS_MODULE);
 562
 563        mtd_for_each_device(mtd)
 564                new->add(mtd);
 565
 566        mutex_unlock(&mtd_table_mutex);
 567}
 568EXPORT_SYMBOL_GPL(register_mtd_user);
 569
 570/**
 571 *      unregister_mtd_user - unregister a 'user' of MTD devices.
 572 *      @old: pointer to notifier info structure
 573 *
 574 *      Removes a callback function pair from the list of 'users' to be
 575 *      notified upon addition or removal of MTD devices. Causes the
 576 *      'remove' callback to be immediately invoked for each MTD device
 577 *      currently present in the system.
 578 */
 579int unregister_mtd_user (struct mtd_notifier *old)
 580{
 581        struct mtd_info *mtd;
 582
 583        mutex_lock(&mtd_table_mutex);
 584
 585        module_put(THIS_MODULE);
 586
 587        mtd_for_each_device(mtd)
 588                old->remove(mtd);
 589
 590        list_del(&old->list);
 591        mutex_unlock(&mtd_table_mutex);
 592        return 0;
 593}
 594EXPORT_SYMBOL_GPL(unregister_mtd_user);
 595
 596/**
 597 *      get_mtd_device - obtain a validated handle for an MTD device
 598 *      @mtd: last known address of the required MTD device
 599 *      @num: internal device number of the required MTD device
 600 *
 601 *      Given a number and NULL address, return the num'th entry in the device
 602 *      table, if any.  Given an address and num == -1, search the device table
 603 *      for a device with that address and return if it's still present. Given
 604 *      both, return the num'th driver only if its address matches. Return
 605 *      error code if not.
 606 */
 607struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
 608{
 609        struct mtd_info *ret = NULL, *other;
 610        int err = -ENODEV;
 611
 612        mutex_lock(&mtd_table_mutex);
 613
 614        if (num == -1) {
 615                mtd_for_each_device(other) {
 616                        if (other == mtd) {
 617                                ret = mtd;
 618                                break;
 619                        }
 620                }
 621        } else if (num >= 0) {
 622                ret = idr_find(&mtd_idr, num);
 623                if (mtd && mtd != ret)
 624                        ret = NULL;
 625        }
 626
 627        if (!ret) {
 628                ret = ERR_PTR(err);
 629                goto out;
 630        }
 631
 632        err = __get_mtd_device(ret);
 633        if (err)
 634                ret = ERR_PTR(err);
 635out:
 636        mutex_unlock(&mtd_table_mutex);
 637        return ret;
 638}
 639EXPORT_SYMBOL_GPL(get_mtd_device);
 640
 641
 642int __get_mtd_device(struct mtd_info *mtd)
 643{
 644        int err;
 645
 646        if (!try_module_get(mtd->owner))
 647                return -ENODEV;
 648
 649        if (mtd->_get_device) {
 650                err = mtd->_get_device(mtd);
 651
 652                if (err) {
 653                        module_put(mtd->owner);
 654                        return err;
 655                }
 656        }
 657        mtd->usecount++;
 658        return 0;
 659}
 660EXPORT_SYMBOL_GPL(__get_mtd_device);
 661
 662/**
 663 *      get_mtd_device_nm - obtain a validated handle for an MTD device by
 664 *      device name
 665 *      @name: MTD device name to open
 666 *
 667 *      This function returns MTD device description structure in case of
 668 *      success and an error code in case of failure.
 669 */
 670struct mtd_info *get_mtd_device_nm(const char *name)
 671{
 672        int err = -ENODEV;
 673        struct mtd_info *mtd = NULL, *other;
 674
 675        mutex_lock(&mtd_table_mutex);
 676
 677        mtd_for_each_device(other) {
 678                if (!strcmp(name, other->name)) {
 679                        mtd = other;
 680                        break;
 681                }
 682        }
 683
 684        if (!mtd)
 685                goto out_unlock;
 686
 687        err = __get_mtd_device(mtd);
 688        if (err)
 689                goto out_unlock;
 690
 691        mutex_unlock(&mtd_table_mutex);
 692        return mtd;
 693
 694out_unlock:
 695        mutex_unlock(&mtd_table_mutex);
 696        return ERR_PTR(err);
 697}
 698EXPORT_SYMBOL_GPL(get_mtd_device_nm);
 699
 700void put_mtd_device(struct mtd_info *mtd)
 701{
 702        mutex_lock(&mtd_table_mutex);
 703        __put_mtd_device(mtd);
 704        mutex_unlock(&mtd_table_mutex);
 705
 706}
 707EXPORT_SYMBOL_GPL(put_mtd_device);
 708
 709void __put_mtd_device(struct mtd_info *mtd)
 710{
 711        --mtd->usecount;
 712        BUG_ON(mtd->usecount < 0);
 713
 714        if (mtd->_put_device)
 715                mtd->_put_device(mtd);
 716
 717        module_put(mtd->owner);
 718}
 719EXPORT_SYMBOL_GPL(__put_mtd_device);
 720
 721/*
 722 * Erase is an asynchronous operation.  Device drivers are supposed
 723 * to call instr->callback() whenever the operation completes, even
 724 * if it completes with a failure.
 725 * Callers are supposed to pass a callback function and wait for it
 726 * to be called before writing to the block.
 727 */
 728int mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
 729{
 730        if (instr->addr > mtd->size || instr->len > mtd->size - instr->addr)
 731                return -EINVAL;
 732        if (!(mtd->flags & MTD_WRITEABLE))
 733                return -EROFS;
 734        instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
 735        if (!instr->len) {
 736                instr->state = MTD_ERASE_DONE;
 737                mtd_erase_callback(instr);
 738                return 0;
 739        }
 740        return mtd->_erase(mtd, instr);
 741}
 742EXPORT_SYMBOL_GPL(mtd_erase);
 743
 744/*
 745 * This stuff for eXecute-In-Place. phys is optional and may be set to NULL.
 746 */
 747int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
 748              void **virt, resource_size_t *phys)
 749{
 750        *retlen = 0;
 751        *virt = NULL;
 752        if (phys)
 753                *phys = 0;
 754        if (!mtd->_point)
 755                return -EOPNOTSUPP;
 756        if (from < 0 || from > mtd->size || len > mtd->size - from)
 757                return -EINVAL;
 758        if (!len)
 759                return 0;
 760        return mtd->_point(mtd, from, len, retlen, virt, phys);
 761}
 762EXPORT_SYMBOL_GPL(mtd_point);
 763
 764/* We probably shouldn't allow XIP if the unpoint isn't a NULL */
 765int mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
 766{
 767        if (!mtd->_point)
 768                return -EOPNOTSUPP;
 769        if (from < 0 || from > mtd->size || len > mtd->size - from)
 770                return -EINVAL;
 771        if (!len)
 772                return 0;
 773        return mtd->_unpoint(mtd, from, len);
 774}
 775EXPORT_SYMBOL_GPL(mtd_unpoint);
 776
 777/*
 778 * Allow NOMMU mmap() to directly map the device (if not NULL)
 779 * - return the address to which the offset maps
 780 * - return -ENOSYS to indicate refusal to do the mapping
 781 */
 782unsigned long mtd_get_unmapped_area(struct mtd_info *mtd, unsigned long len,
 783                                    unsigned long offset, unsigned long flags)
 784{
 785        if (!mtd->_get_unmapped_area)
 786                return -EOPNOTSUPP;
 787        if (offset > mtd->size || len > mtd->size - offset)
 788                return -EINVAL;
 789        return mtd->_get_unmapped_area(mtd, len, offset, flags);
 790}
 791EXPORT_SYMBOL_GPL(mtd_get_unmapped_area);
 792
 793int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
 794             u_char *buf)
 795{
 796        int ret_code;
 797        *retlen = 0;
 798        if (from < 0 || from > mtd->size || len > mtd->size - from)
 799                return -EINVAL;
 800        if (!len)
 801                return 0;
 802
 803        /*
 804         * In the absence of an error, drivers return a non-negative integer
 805         * representing the maximum number of bitflips that were corrected on
 806         * any one ecc region (if applicable; zero otherwise).
 807         */
 808        ret_code = mtd->_read(mtd, from, len, retlen, buf);
 809        if (unlikely(ret_code < 0))
 810                return ret_code;
 811        if (mtd->ecc_strength == 0)
 812                return 0;       /* device lacks ecc */
 813        return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
 814}
 815EXPORT_SYMBOL_GPL(mtd_read);
 816
 817int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
 818              const u_char *buf)
 819{
 820        *retlen = 0;
 821        if (to < 0 || to > mtd->size || len > mtd->size - to)
 822                return -EINVAL;
 823        if (!mtd->_write || !(mtd->flags & MTD_WRITEABLE))
 824                return -EROFS;
 825        if (!len)
 826                return 0;
 827        return mtd->_write(mtd, to, len, retlen, buf);
 828}
 829EXPORT_SYMBOL_GPL(mtd_write);
 830
 831/*
 832 * In blackbox flight recorder like scenarios we want to make successful writes
 833 * in interrupt context. panic_write() is only intended to be called when its
 834 * known the kernel is about to panic and we need the write to succeed. Since
 835 * the kernel is not going to be running for much longer, this function can
 836 * break locks and delay to ensure the write succeeds (but not sleep).
 837 */
 838int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
 839                    const u_char *buf)
 840{
 841        *retlen = 0;
 842        if (!mtd->_panic_write)
 843                return -EOPNOTSUPP;
 844        if (to < 0 || to > mtd->size || len > mtd->size - to)
 845                return -EINVAL;
 846        if (!(mtd->flags & MTD_WRITEABLE))
 847                return -EROFS;
 848        if (!len)
 849                return 0;
 850        return mtd->_panic_write(mtd, to, len, retlen, buf);
 851}
 852EXPORT_SYMBOL_GPL(mtd_panic_write);
 853
 854int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
 855{
 856        int ret_code;
 857        ops->retlen = ops->oobretlen = 0;
 858        if (!mtd->_read_oob)
 859                return -EOPNOTSUPP;
 860        /*
 861         * In cases where ops->datbuf != NULL, mtd->_read_oob() has semantics
 862         * similar to mtd->_read(), returning a non-negative integer
 863         * representing max bitflips. In other cases, mtd->_read_oob() may
 864         * return -EUCLEAN. In all cases, perform similar logic to mtd_read().
 865         */
 866        ret_code = mtd->_read_oob(mtd, from, ops);
 867        if (unlikely(ret_code < 0))
 868                return ret_code;
 869        if (mtd->ecc_strength == 0)
 870                return 0;       /* device lacks ecc */
 871        return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
 872}
 873EXPORT_SYMBOL_GPL(mtd_read_oob);
 874
 875/*
 876 * Method to access the protection register area, present in some flash
 877 * devices. The user data is one time programmable but the factory data is read
 878 * only.
 879 */
 880int mtd_get_fact_prot_info(struct mtd_info *mtd, struct otp_info *buf,
 881                           size_t len)
 882{
 883        if (!mtd->_get_fact_prot_info)
 884                return -EOPNOTSUPP;
 885        if (!len)
 886                return 0;
 887        return mtd->_get_fact_prot_info(mtd, buf, len);
 888}
 889EXPORT_SYMBOL_GPL(mtd_get_fact_prot_info);
 890
 891int mtd_read_fact_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
 892                           size_t *retlen, u_char *buf)
 893{
 894        *retlen = 0;
 895        if (!mtd->_read_fact_prot_reg)
 896                return -EOPNOTSUPP;
 897        if (!len)
 898                return 0;
 899        return mtd->_read_fact_prot_reg(mtd, from, len, retlen, buf);
 900}
 901EXPORT_SYMBOL_GPL(mtd_read_fact_prot_reg);
 902
 903int mtd_get_user_prot_info(struct mtd_info *mtd, struct otp_info *buf,
 904                           size_t len)
 905{
 906        if (!mtd->_get_user_prot_info)
 907                return -EOPNOTSUPP;
 908        if (!len)
 909                return 0;
 910        return mtd->_get_user_prot_info(mtd, buf, len);
 911}
 912EXPORT_SYMBOL_GPL(mtd_get_user_prot_info);
 913
 914int mtd_read_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
 915                           size_t *retlen, u_char *buf)
 916{
 917        *retlen = 0;
 918        if (!mtd->_read_user_prot_reg)
 919                return -EOPNOTSUPP;
 920        if (!len)
 921                return 0;
 922        return mtd->_read_user_prot_reg(mtd, from, len, retlen, buf);
 923}
 924EXPORT_SYMBOL_GPL(mtd_read_user_prot_reg);
 925
 926int mtd_write_user_prot_reg(struct mtd_info *mtd, loff_t to, size_t len,
 927                            size_t *retlen, u_char *buf)
 928{
 929        *retlen = 0;
 930        if (!mtd->_write_user_prot_reg)
 931                return -EOPNOTSUPP;
 932        if (!len)
 933                return 0;
 934        return mtd->_write_user_prot_reg(mtd, to, len, retlen, buf);
 935}
 936EXPORT_SYMBOL_GPL(mtd_write_user_prot_reg);
 937
 938int mtd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len)
 939{
 940        if (!mtd->_lock_user_prot_reg)
 941                return -EOPNOTSUPP;
 942        if (!len)
 943                return 0;
 944        return mtd->_lock_user_prot_reg(mtd, from, len);
 945}
 946EXPORT_SYMBOL_GPL(mtd_lock_user_prot_reg);
 947
 948/* Chip-supported device locking */
 949int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 950{
 951        if (!mtd->_lock)
 952                return -EOPNOTSUPP;
 953        if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
 954                return -EINVAL;
 955        if (!len)
 956                return 0;
 957        return mtd->_lock(mtd, ofs, len);
 958}
 959EXPORT_SYMBOL_GPL(mtd_lock);
 960
 961int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 962{
 963        if (!mtd->_unlock)
 964                return -EOPNOTSUPP;
 965        if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
 966                return -EINVAL;
 967        if (!len)
 968                return 0;
 969        return mtd->_unlock(mtd, ofs, len);
 970}
 971EXPORT_SYMBOL_GPL(mtd_unlock);
 972
 973int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 974{
 975        if (!mtd->_is_locked)
 976                return -EOPNOTSUPP;
 977        if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
 978                return -EINVAL;
 979        if (!len)
 980                return 0;
 981        return mtd->_is_locked(mtd, ofs, len);
 982}
 983EXPORT_SYMBOL_GPL(mtd_is_locked);
 984
 985int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs)
 986{
 987        if (!mtd->_block_isbad)
 988                return 0;
 989        if (ofs < 0 || ofs > mtd->size)
 990                return -EINVAL;
 991        return mtd->_block_isbad(mtd, ofs);
 992}
 993EXPORT_SYMBOL_GPL(mtd_block_isbad);
 994
 995int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs)
 996{
 997        if (!mtd->_block_markbad)
 998                return -EOPNOTSUPP;
 999        if (ofs < 0 || ofs > mtd->size)
1000                return -EINVAL;
1001        if (!(mtd->flags & MTD_WRITEABLE))
1002                return -EROFS;
1003        return mtd->_block_markbad(mtd, ofs);
1004}
1005EXPORT_SYMBOL_GPL(mtd_block_markbad);
1006
1007/*
1008 * default_mtd_writev - the default writev method
1009 * @mtd: mtd device description object pointer
1010 * @vecs: the vectors to write
1011 * @count: count of vectors in @vecs
1012 * @to: the MTD device offset to write to
1013 * @retlen: on exit contains the count of bytes written to the MTD device.
1014 *
1015 * This function returns zero in case of success and a negative error code in
1016 * case of failure.
1017 */
1018static int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
1019                              unsigned long count, loff_t to, size_t *retlen)
1020{
1021        unsigned long i;
1022        size_t totlen = 0, thislen;
1023        int ret = 0;
1024
1025        for (i = 0; i < count; i++) {
1026                if (!vecs[i].iov_len)
1027                        continue;
1028                ret = mtd_write(mtd, to, vecs[i].iov_len, &thislen,
1029                                vecs[i].iov_base);
1030                totlen += thislen;
1031                if (ret || thislen != vecs[i].iov_len)
1032                        break;
1033                to += vecs[i].iov_len;
1034        }
1035        *retlen = totlen;
1036        return ret;
1037}
1038
1039/*
1040 * mtd_writev - the vector-based MTD write method
1041 * @mtd: mtd device description object pointer
1042 * @vecs: the vectors to write
1043 * @count: count of vectors in @vecs
1044 * @to: the MTD device offset to write to
1045 * @retlen: on exit contains the count of bytes written to the MTD device.
1046 *
1047 * This function returns zero in case of success and a negative error code in
1048 * case of failure.
1049 */
1050int mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
1051               unsigned long count, loff_t to, size_t *retlen)
1052{
1053        *retlen = 0;
1054        if (!(mtd->flags & MTD_WRITEABLE))
1055                return -EROFS;
1056        if (!mtd->_writev)
1057                return default_mtd_writev(mtd, vecs, count, to, retlen);
1058        return mtd->_writev(mtd, vecs, count, to, retlen);
1059}
1060EXPORT_SYMBOL_GPL(mtd_writev);
1061
1062/**
1063 * mtd_kmalloc_up_to - allocate a contiguous buffer up to the specified size
1064 * @mtd: mtd device description object pointer
1065 * @size: a pointer to the ideal or maximum size of the allocation, points
1066 *        to the actual allocation size on success.
1067 *
1068 * This routine attempts to allocate a contiguous kernel buffer up to
1069 * the specified size, backing off the size of the request exponentially
1070 * until the request succeeds or until the allocation size falls below
1071 * the system page size. This attempts to make sure it does not adversely
1072 * impact system performance, so when allocating more than one page, we
1073 * ask the memory allocator to avoid re-trying, swapping, writing back
1074 * or performing I/O.
1075 *
1076 * Note, this function also makes sure that the allocated buffer is aligned to
1077 * the MTD device's min. I/O unit, i.e. the "mtd->writesize" value.
1078 *
1079 * This is called, for example by mtd_{read,write} and jffs2_scan_medium,
1080 * to handle smaller (i.e. degraded) buffer allocations under low- or
1081 * fragmented-memory situations where such reduced allocations, from a
1082 * requested ideal, are allowed.
1083 *
1084 * Returns a pointer to the allocated buffer on success; otherwise, NULL.
1085 */
1086void *mtd_kmalloc_up_to(const struct mtd_info *mtd, size_t *size)
1087{
1088        gfp_t flags = __GFP_NOWARN | __GFP_WAIT |
1089                       __GFP_NORETRY | __GFP_NO_KSWAPD;
1090        size_t min_alloc = max_t(size_t, mtd->writesize, PAGE_SIZE);
1091        void *kbuf;
1092
1093        *size = min_t(size_t, *size, KMALLOC_MAX_SIZE);
1094
1095        while (*size > min_alloc) {
1096                kbuf = kmalloc(*size, flags);
1097                if (kbuf)
1098                        return kbuf;
1099
1100                *size >>= 1;
1101                *size = ALIGN(*size, mtd->writesize);
1102        }
1103
1104        /*
1105         * For the last resort allocation allow 'kmalloc()' to do all sorts of
1106         * things (write-back, dropping caches, etc) by using GFP_KERNEL.
1107         */
1108        return kmalloc(*size, GFP_KERNEL);
1109}
1110EXPORT_SYMBOL_GPL(mtd_kmalloc_up_to);
1111
1112#ifdef CONFIG_PROC_FS
1113
1114/*====================================================================*/
1115/* Support for /proc/mtd */
1116
1117static int mtd_proc_show(struct seq_file *m, void *v)
1118{
1119        struct mtd_info *mtd;
1120
1121        seq_puts(m, "dev:    size   erasesize  name\n");
1122        mutex_lock(&mtd_table_mutex);
1123        mtd_for_each_device(mtd) {
1124                seq_printf(m, "mtd%d: %8.8llx %8.8x \"%s\"\n",
1125                           mtd->index, (unsigned long long)mtd->size,
1126                           mtd->erasesize, mtd->name);
1127        }
1128        mutex_unlock(&mtd_table_mutex);
1129        return 0;
1130}
1131
1132static int mtd_proc_open(struct inode *inode, struct file *file)
1133{
1134        return single_open(file, mtd_proc_show, NULL);
1135}
1136
1137static const struct file_operations mtd_proc_ops = {
1138        .open           = mtd_proc_open,
1139        .read           = seq_read,
1140        .llseek         = seq_lseek,
1141        .release        = single_release,
1142};
1143#endif /* CONFIG_PROC_FS */
1144
1145/*====================================================================*/
1146/* Init code */
1147
1148static int __init mtd_bdi_init(struct backing_dev_info *bdi, const char *name)
1149{
1150        int ret;
1151
1152        ret = bdi_init(bdi);
1153        if (!ret)
1154                ret = bdi_register(bdi, NULL, "%s", name);
1155
1156        if (ret)
1157                bdi_destroy(bdi);
1158
1159        return ret;
1160}
1161
1162static struct proc_dir_entry *proc_mtd;
1163
1164static int __init init_mtd(void)
1165{
1166        int ret;
1167
1168        ret = class_register(&mtd_class);
1169        if (ret)
1170                goto err_reg;
1171
1172        ret = mtd_bdi_init(&mtd_bdi_unmappable, "mtd-unmap");
1173        if (ret)
1174                goto err_bdi1;
1175
1176        ret = mtd_bdi_init(&mtd_bdi_ro_mappable, "mtd-romap");
1177        if (ret)
1178                goto err_bdi2;
1179
1180        ret = mtd_bdi_init(&mtd_bdi_rw_mappable, "mtd-rwmap");
1181        if (ret)
1182                goto err_bdi3;
1183
1184        proc_mtd = proc_create("mtd", 0, NULL, &mtd_proc_ops);
1185
1186        ret = init_mtdchar();
1187        if (ret)
1188                goto out_procfs;
1189
1190        return 0;
1191
1192out_procfs:
1193        if (proc_mtd)
1194                remove_proc_entry("mtd", NULL);
1195err_bdi3:
1196        bdi_destroy(&mtd_bdi_ro_mappable);
1197err_bdi2:
1198        bdi_destroy(&mtd_bdi_unmappable);
1199err_bdi1:
1200        class_unregister(&mtd_class);
1201err_reg:
1202        pr_err("Error registering mtd class or bdi: %d\n", ret);
1203        return ret;
1204}
1205
1206static void __exit cleanup_mtd(void)
1207{
1208        cleanup_mtdchar();
1209        if (proc_mtd)
1210                remove_proc_entry("mtd", NULL);
1211        class_unregister(&mtd_class);
1212        bdi_destroy(&mtd_bdi_unmappable);
1213        bdi_destroy(&mtd_bdi_ro_mappable);
1214        bdi_destroy(&mtd_bdi_rw_mappable);
1215}
1216
1217module_init(init_mtd);
1218module_exit(cleanup_mtd);
1219
1220MODULE_LICENSE("GPL");
1221MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
1222MODULE_DESCRIPTION("Core MTD registration and access routines");
1223
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.