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