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        do {
 353                if (!idr_pre_get(&mtd_idr, GFP_KERNEL))
 354                        goto fail_locked;
 355                error = idr_get_new(&mtd_idr, mtd, &i);
 356        } while (error == -EAGAIN);
 357
 358        if (error)
 359                goto fail_locked;
 360
 361        mtd->index = i;
 362        mtd->usecount = 0;
 363
 364        /* default value if not set by driver */
 365        if (mtd->bitflip_threshold == 0)
 366                mtd->bitflip_threshold = mtd->ecc_strength;
 367
 368        if (is_power_of_2(mtd->erasesize))
 369                mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
 370        else
 371                mtd->erasesize_shift = 0;
 372
 373        if (is_power_of_2(mtd->writesize))
 374                mtd->writesize_shift = ffs(mtd->writesize) - 1;
 375        else
 376                mtd->writesize_shift = 0;
 377
 378        mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
 379        mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
 380
 381        /* Some chips always power up locked. Unlock them now */
 382        if ((mtd->flags & MTD_WRITEABLE) && (mtd->flags & MTD_POWERUP_LOCK)) {
 383                error = mtd_unlock(mtd, 0, mtd->size);
 384                if (error && error != -EOPNOTSUPP)
 385                        printk(KERN_WARNING
 386                               "%s: unlock failed, writes may not work\n",
 387                               mtd->name);
 388        }
 389
 390        /* Caller should have set dev.parent to match the
 391         * physical device.
 392         */
 393        mtd->dev.type = &mtd_devtype;
 394        mtd->dev.class = &mtd_class;
 395        mtd->dev.devt = MTD_DEVT(i);
 396        dev_set_name(&mtd->dev, "mtd%d", i);
 397        dev_set_drvdata(&mtd->dev, mtd);
 398        if (device_register(&mtd->dev) != 0)
 399                goto fail_added;
 400
 401        if (MTD_DEVT(i))
 402                device_create(&mtd_class, mtd->dev.parent,
 403                              MTD_DEVT(i) + 1,
 404                              NULL, "mtd%dro", i);
 405
 406        pr_debug("mtd: Giving out device %d to %s\n", i, mtd->name);
 407        /* No need to get a refcount on the module containing
 408           the notifier, since we hold the mtd_table_mutex */
 409        list_for_each_entry(not, &mtd_notifiers, list)
 410                not->add(mtd);
 411
 412        mutex_unlock(&mtd_table_mutex);
 413        /* We _know_ we aren't being removed, because
 414           our caller is still holding us here. So none
 415           of this try_ nonsense, and no bitching about it
 416           either. :) */
 417        __module_get(THIS_MODULE);
 418        return 0;
 419
 420fail_added:
 421        idr_remove(&mtd_idr, i);
 422fail_locked:
 423        mutex_unlock(&mtd_table_mutex);
 424        return 1;
 425}
 426
 427/**
 428 *      del_mtd_device - unregister an MTD device
 429 *      @mtd: pointer to MTD device info structure
 430 *
 431 *      Remove a device from the list of MTD devices present in the system,
 432 *      and notify each currently active MTD 'user' of its departure.
 433 *      Returns zero on success or 1 on failure, which currently will happen
 434 *      if the requested device does not appear to be present in the list.
 435 */
 436
 437int del_mtd_device(struct mtd_info *mtd)
 438{
 439        int ret;
 440        struct mtd_notifier *not;
 441
 442        mutex_lock(&mtd_table_mutex);
 443
 444        if (idr_find(&mtd_idr, mtd->index) != mtd) {
 445                ret = -ENODEV;
 446                goto out_error;
 447        }
 448
 449        /* No need to get a refcount on the module containing
 450                the notifier, since we hold the mtd_table_mutex */
 451        list_for_each_entry(not, &mtd_notifiers, list)
 452                not->remove(mtd);
 453
 454        if (mtd->usecount) {
 455                printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
 456                       mtd->index, mtd->name, mtd->usecount);
 457                ret = -EBUSY;
 458        } else {
 459                device_unregister(&mtd->dev);
 460
 461                idr_remove(&mtd_idr, mtd->index);
 462
 463                module_put(THIS_MODULE);
 464                ret = 0;
 465        }
 466
 467out_error:
 468        mutex_unlock(&mtd_table_mutex);
 469        return ret;
 470}
 471
 472/**
 473 * mtd_device_parse_register - parse partitions and register an MTD device.
 474 *
 475 * @mtd: the MTD device to register
 476 * @types: the list of MTD partition probes to try, see
 477 *         'parse_mtd_partitions()' for more information
 478 * @parser_data: MTD partition parser-specific data
 479 * @parts: fallback partition information to register, if parsing fails;
 480 *         only valid if %nr_parts > %0
 481 * @nr_parts: the number of partitions in parts, if zero then the full
 482 *            MTD device is registered if no partition info is found
 483 *
 484 * This function aggregates MTD partitions parsing (done by
 485 * 'parse_mtd_partitions()') and MTD device and partitions registering. It
 486 * basically follows the most common pattern found in many MTD drivers:
 487 *
 488 * * It first tries to probe partitions on MTD device @mtd using parsers
 489 *   specified in @types (if @types is %NULL, then the default list of parsers
 490 *   is used, see 'parse_mtd_partitions()' for more information). If none are
 491 *   found this functions tries to fallback to information specified in
 492 *   @parts/@nr_parts.
 493 * * If any partitioning info was found, this function registers the found
 494 *   partitions.
 495 * * If no partitions were found this function just registers the MTD device
 496 *   @mtd and exits.
 497 *
 498 * Returns zero in case of success and a negative error code in case of failure.
 499 */
 500int mtd_device_parse_register(struct mtd_info *mtd, const char **types,
 501                              struct mtd_part_parser_data *parser_data,
 502                              const struct mtd_partition *parts,
 503                              int nr_parts)
 504{
 505        int err;
 506        struct mtd_partition *real_parts;
 507
 508        err = parse_mtd_partitions(mtd, types, &real_parts, parser_data);
 509        if (err <= 0 && nr_parts && parts) {
 510                real_parts = kmemdup(parts, sizeof(*parts) * nr_parts,
 511                                     GFP_KERNEL);
 512                if (!real_parts)
 513                        err = -ENOMEM;
 514                else
 515                        err = nr_parts;
 516        }
 517
 518        if (err > 0) {
 519                err = add_mtd_partitions(mtd, real_parts, err);
 520                kfree(real_parts);
 521        } else if (err == 0) {
 522                err = add_mtd_device(mtd);
 523                if (err == 1)
 524                        err = -ENODEV;
 525        }
 526
 527        return err;
 528}
 529EXPORT_SYMBOL_GPL(mtd_device_parse_register);
 530
 531/**
 532 * mtd_device_unregister - unregister an existing MTD device.
 533 *
 534 * @master: the MTD device to unregister.  This will unregister both the master
 535 *          and any partitions if registered.
 536 */
 537int mtd_device_unregister(struct mtd_info *master)
 538{
 539        int err;
 540
 541        err = del_mtd_partitions(master);
 542        if (err)
 543                return err;
 544
 545        if (!device_is_registered(&master->dev))
 546                return 0;
 547
 548        return del_mtd_device(master);
 549}
 550EXPORT_SYMBOL_GPL(mtd_device_unregister);
 551
 552/**
 553 *      register_mtd_user - register a 'user' of MTD devices.
 554 *      @new: pointer to notifier info structure
 555 *
 556 *      Registers a pair of callbacks function to be called upon addition
 557 *      or removal of MTD devices. Causes the 'add' callback to be immediately
 558 *      invoked for each MTD device currently present in the system.
 559 */
 560void register_mtd_user (struct mtd_notifier *new)
 561{
 562        struct mtd_info *mtd;
 563
 564        mutex_lock(&mtd_table_mutex);
 565
 566        list_add(&new->list, &mtd_notifiers);
 567
 568        __module_get(THIS_MODULE);
 569
 570        mtd_for_each_device(mtd)
 571                new->add(mtd);
 572
 573        mutex_unlock(&mtd_table_mutex);
 574}
 575EXPORT_SYMBOL_GPL(register_mtd_user);
 576
 577/**
 578 *      unregister_mtd_user - unregister a 'user' of MTD devices.
 579 *      @old: pointer to notifier info structure
 580 *
 581 *      Removes a callback function pair from the list of 'users' to be
 582 *      notified upon addition or removal of MTD devices. Causes the
 583 *      'remove' callback to be immediately invoked for each MTD device
 584 *      currently present in the system.
 585 */
 586int unregister_mtd_user (struct mtd_notifier *old)
 587{
 588        struct mtd_info *mtd;
 589
 590        mutex_lock(&mtd_table_mutex);
 591
 592        module_put(THIS_MODULE);
 593
 594        mtd_for_each_device(mtd)
 595                old->remove(mtd);
 596
 597        list_del(&old->list);
 598        mutex_unlock(&mtd_table_mutex);
 599        return 0;
 600}
 601EXPORT_SYMBOL_GPL(unregister_mtd_user);
 602
 603/**
 604 *      get_mtd_device - obtain a validated handle for an MTD device
 605 *      @mtd: last known address of the required MTD device
 606 *      @num: internal device number of the required MTD device
 607 *
 608 *      Given a number and NULL address, return the num'th entry in the device
 609 *      table, if any.  Given an address and num == -1, search the device table
 610 *      for a device with that address and return if it's still present. Given
 611 *      both, return the num'th driver only if its address matches. Return
 612 *      error code if not.
 613 */
 614struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
 615{
 616        struct mtd_info *ret = NULL, *other;
 617        int err = -ENODEV;
 618
 619        mutex_lock(&mtd_table_mutex);
 620
 621        if (num == -1) {
 622                mtd_for_each_device(other) {
 623                        if (other == mtd) {
 624                                ret = mtd;
 625                                break;
 626                        }
 627                }
 628        } else if (num >= 0) {
 629                ret = idr_find(&mtd_idr, num);
 630                if (mtd && mtd != ret)
 631                        ret = NULL;
 632        }
 633
 634        if (!ret) {
 635                ret = ERR_PTR(err);
 636                goto out;
 637        }
 638
 639        err = __get_mtd_device(ret);
 640        if (err)
 641                ret = ERR_PTR(err);
 642out:
 643        mutex_unlock(&mtd_table_mutex);
 644        return ret;
 645}
 646EXPORT_SYMBOL_GPL(get_mtd_device);
 647
 648
 649int __get_mtd_device(struct mtd_info *mtd)
 650{
 651        int err;
 652
 653        if (!try_module_get(mtd->owner))
 654                return -ENODEV;
 655
 656        if (mtd->_get_device) {
 657                err = mtd->_get_device(mtd);
 658
 659                if (err) {
 660                        module_put(mtd->owner);
 661                        return err;
 662                }
 663        }
 664        mtd->usecount++;
 665        return 0;
 666}
 667EXPORT_SYMBOL_GPL(__get_mtd_device);
 668
 669/**
 670 *      get_mtd_device_nm - obtain a validated handle for an MTD device by
 671 *      device name
 672 *      @name: MTD device name to open
 673 *
 674 *      This function returns MTD device description structure in case of
 675 *      success and an error code in case of failure.
 676 */
 677struct mtd_info *get_mtd_device_nm(const char *name)
 678{
 679        int err = -ENODEV;
 680        struct mtd_info *mtd = NULL, *other;
 681
 682        mutex_lock(&mtd_table_mutex);
 683
 684        mtd_for_each_device(other) {
 685                if (!strcmp(name, other->name)) {
 686                        mtd = other;
 687                        break;
 688                }
 689        }
 690
 691        if (!mtd)
 692                goto out_unlock;
 693
 694        err = __get_mtd_device(mtd);
 695        if (err)
 696                goto out_unlock;
 697
 698        mutex_unlock(&mtd_table_mutex);
 699        return mtd;
 700
 701out_unlock:
 702        mutex_unlock(&mtd_table_mutex);
 703        return ERR_PTR(err);
 704}
 705EXPORT_SYMBOL_GPL(get_mtd_device_nm);
 706
 707void put_mtd_device(struct mtd_info *mtd)
 708{
 709        mutex_lock(&mtd_table_mutex);
 710        __put_mtd_device(mtd);
 711        mutex_unlock(&mtd_table_mutex);
 712
 713}
 714EXPORT_SYMBOL_GPL(put_mtd_device);
 715
 716void __put_mtd_device(struct mtd_info *mtd)
 717{
 718        --mtd->usecount;
 719        BUG_ON(mtd->usecount < 0);
 720
 721        if (mtd->_put_device)
 722                mtd->_put_device(mtd);
 723
 724        module_put(mtd->owner);
 725}
 726EXPORT_SYMBOL_GPL(__put_mtd_device);
 727
 728/*
 729 * Erase is an asynchronous operation.  Device drivers are supposed
 730 * to call instr->callback() whenever the operation completes, even
 731 * if it completes with a failure.
 732 * Callers are supposed to pass a callback function and wait for it
 733 * to be called before writing to the block.
 734 */
 735int mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
 736{
 737        if (instr->addr > mtd->size || instr->len > mtd->size - instr->addr)
 738                return -EINVAL;
 739        if (!(mtd->flags & MTD_WRITEABLE))
 740                return -EROFS;
 741        instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
 742        if (!instr->len) {
 743                instr->state = MTD_ERASE_DONE;
 744                mtd_erase_callback(instr);
 745                return 0;
 746        }
 747        return mtd->_erase(mtd, instr);
 748}
 749EXPORT_SYMBOL_GPL(mtd_erase);
 750
 751/*
 752 * This stuff for eXecute-In-Place. phys is optional and may be set to NULL.
 753 */
 754int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
 755              void **virt, resource_size_t *phys)
 756{
 757        *retlen = 0;
 758        *virt = NULL;
 759        if (phys)
 760                *phys = 0;
 761        if (!mtd->_point)
 762                return -EOPNOTSUPP;
 763        if (from < 0 || from > mtd->size || len > mtd->size - from)
 764                return -EINVAL;
 765        if (!len)
 766                return 0;
 767        return mtd->_point(mtd, from, len, retlen, virt, phys);
 768}
 769EXPORT_SYMBOL_GPL(mtd_point);
 770
 771/* We probably shouldn't allow XIP if the unpoint isn't a NULL */
 772int mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
 773{
 774        if (!mtd->_point)
 775                return -EOPNOTSUPP;
 776        if (from < 0 || from > mtd->size || len > mtd->size - from)
 777                return -EINVAL;
 778        if (!len)
 779                return 0;
 780        return mtd->_unpoint(mtd, from, len);
 781}
 782EXPORT_SYMBOL_GPL(mtd_unpoint);
 783
 784/*
 785 * Allow NOMMU mmap() to directly map the device (if not NULL)
 786 * - return the address to which the offset maps
 787 * - return -ENOSYS to indicate refusal to do the mapping
 788 */
 789unsigned long mtd_get_unmapped_area(struct mtd_info *mtd, unsigned long len,
 790                                    unsigned long offset, unsigned long flags)
 791{
 792        if (!mtd->_get_unmapped_area)
 793                return -EOPNOTSUPP;
 794        if (offset > mtd->size || len > mtd->size - offset)
 795                return -EINVAL;
 796        return mtd->_get_unmapped_area(mtd, len, offset, flags);
 797}
 798EXPORT_SYMBOL_GPL(mtd_get_unmapped_area);
 799
 800int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
 801             u_char *buf)
 802{
 803        int ret_code;
 804        *retlen = 0;
 805        if (from < 0 || from > mtd->size || len > mtd->size - from)
 806                return -EINVAL;
 807        if (!len)
 808                return 0;
 809
 810        /*
 811         * In the absence of an error, drivers return a non-negative integer
 812         * representing the maximum number of bitflips that were corrected on
 813         * any one ecc region (if applicable; zero otherwise).
 814         */
 815        ret_code = mtd->_read(mtd, from, len, retlen, buf);
 816        if (unlikely(ret_code < 0))
 817                return ret_code;
 818        if (mtd->ecc_strength == 0)
 819                return 0;       /* device lacks ecc */
 820        return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
 821}
 822EXPORT_SYMBOL_GPL(mtd_read);
 823
 824int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
 825              const u_char *buf)
 826{
 827        *retlen = 0;
 828        if (to < 0 || to > mtd->size || len > mtd->size - to)
 829                return -EINVAL;
 830        if (!mtd->_write || !(mtd->flags & MTD_WRITEABLE))
 831                return -EROFS;
 832        if (!len)
 833                return 0;
 834        return mtd->_write(mtd, to, len, retlen, buf);
 835}
 836EXPORT_SYMBOL_GPL(mtd_write);
 837
 838/*
 839 * In blackbox flight recorder like scenarios we want to make successful writes
 840 * in interrupt context. panic_write() is only intended to be called when its
 841 * known the kernel is about to panic and we need the write to succeed. Since
 842 * the kernel is not going to be running for much longer, this function can
 843 * break locks and delay to ensure the write succeeds (but not sleep).
 844 */
 845int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
 846                    const u_char *buf)
 847{
 848        *retlen = 0;
 849        if (!mtd->_panic_write)
 850                return -EOPNOTSUPP;
 851        if (to < 0 || to > mtd->size || len > mtd->size - to)
 852                return -EINVAL;
 853        if (!(mtd->flags & MTD_WRITEABLE))
 854                return -EROFS;
 855        if (!len)
 856                return 0;
 857        return mtd->_panic_write(mtd, to, len, retlen, buf);
 858}
 859EXPORT_SYMBOL_GPL(mtd_panic_write);
 860
 861/*
 862 * Method to access the protection register area, present in some flash
 863 * devices. The user data is one time programmable but the factory data is read
 864 * only.
 865 */
 866int mtd_get_fact_prot_info(struct mtd_info *mtd, struct otp_info *buf,
 867                           size_t len)
 868{
 869        if (!mtd->_get_fact_prot_info)
 870                return -EOPNOTSUPP;
 871        if (!len)
 872                return 0;
 873        return mtd->_get_fact_prot_info(mtd, buf, len);
 874}
 875EXPORT_SYMBOL_GPL(mtd_get_fact_prot_info);
 876
 877int mtd_read_fact_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
 878                           size_t *retlen, u_char *buf)
 879{
 880        *retlen = 0;
 881        if (!mtd->_read_fact_prot_reg)
 882                return -EOPNOTSUPP;
 883        if (!len)
 884                return 0;
 885        return mtd->_read_fact_prot_reg(mtd, from, len, retlen, buf);
 886}
 887EXPORT_SYMBOL_GPL(mtd_read_fact_prot_reg);
 888
 889int mtd_get_user_prot_info(struct mtd_info *mtd, struct otp_info *buf,
 890                           size_t len)
 891{
 892        if (!mtd->_get_user_prot_info)
 893                return -EOPNOTSUPP;
 894        if (!len)
 895                return 0;
 896        return mtd->_get_user_prot_info(mtd, buf, len);
 897}
 898EXPORT_SYMBOL_GPL(mtd_get_user_prot_info);
 899
 900int mtd_read_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
 901                           size_t *retlen, u_char *buf)
 902{
 903        *retlen = 0;
 904        if (!mtd->_read_user_prot_reg)
 905                return -EOPNOTSUPP;
 906        if (!len)
 907                return 0;
 908        return mtd->_read_user_prot_reg(mtd, from, len, retlen, buf);
 909}
 910EXPORT_SYMBOL_GPL(mtd_read_user_prot_reg);
 911
 912int mtd_write_user_prot_reg(struct mtd_info *mtd, loff_t to, size_t len,
 913                            size_t *retlen, u_char *buf)
 914{
 915        *retlen = 0;
 916        if (!mtd->_write_user_prot_reg)
 917                return -EOPNOTSUPP;
 918        if (!len)
 919                return 0;
 920        return mtd->_write_user_prot_reg(mtd, to, len, retlen, buf);
 921}
 922EXPORT_SYMBOL_GPL(mtd_write_user_prot_reg);
 923
 924int mtd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len)
 925{
 926        if (!mtd->_lock_user_prot_reg)
 927                return -EOPNOTSUPP;
 928        if (!len)
 929                return 0;
 930        return mtd->_lock_user_prot_reg(mtd, from, len);
 931}
 932EXPORT_SYMBOL_GPL(mtd_lock_user_prot_reg);
 933
 934/* Chip-supported device locking */
 935int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 936{
 937        if (!mtd->_lock)
 938                return -EOPNOTSUPP;
 939        if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
 940                return -EINVAL;
 941        if (!len)
 942                return 0;
 943        return mtd->_lock(mtd, ofs, len);
 944}
 945EXPORT_SYMBOL_GPL(mtd_lock);
 946
 947int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 948{
 949        if (!mtd->_unlock)
 950                return -EOPNOTSUPP;
 951        if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
 952                return -EINVAL;
 953        if (!len)
 954                return 0;
 955        return mtd->_unlock(mtd, ofs, len);
 956}
 957EXPORT_SYMBOL_GPL(mtd_unlock);
 958
 959int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 960{
 961        if (!mtd->_is_locked)
 962                return -EOPNOTSUPP;
 963        if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
 964                return -EINVAL;
 965        if (!len)
 966                return 0;
 967        return mtd->_is_locked(mtd, ofs, len);
 968}
 969EXPORT_SYMBOL_GPL(mtd_is_locked);
 970
 971int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs)
 972{
 973        if (!mtd->_block_isbad)
 974                return 0;
 975        if (ofs < 0 || ofs > mtd->size)
 976                return -EINVAL;
 977        return mtd->_block_isbad(mtd, ofs);
 978}
 979EXPORT_SYMBOL_GPL(mtd_block_isbad);
 980
 981int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs)
 982{
 983        if (!mtd->_block_markbad)
 984                return -EOPNOTSUPP;
 985        if (ofs < 0 || ofs > mtd->size)
 986                return -EINVAL;
 987        if (!(mtd->flags & MTD_WRITEABLE))
 988                return -EROFS;
 989        return mtd->_block_markbad(mtd, ofs);
 990}
 991EXPORT_SYMBOL_GPL(mtd_block_markbad);
 992
 993/*
 994 * default_mtd_writev - the default writev method
 995 * @mtd: mtd device description object pointer
 996 * @vecs: the vectors to write
 997 * @count: count of vectors in @vecs
 998 * @to: the MTD device offset to write to
 999 * @retlen: on exit contains the count of bytes written to the MTD device.
1000 *
1001 * This function returns zero in case of success and a negative error code in
1002 * case of failure.
1003 */
1004static int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
1005                              unsigned long count, loff_t to, size_t *retlen)
1006{
1007        unsigned long i;
1008        size_t totlen = 0, thislen;
1009        int ret = 0;
1010
1011        for (i = 0; i < count; i++) {
1012                if (!vecs[i].iov_len)
1013                        continue;
1014                ret = mtd_write(mtd, to, vecs[i].iov_len, &thislen,
1015                                vecs[i].iov_base);
1016                totlen += thislen;
1017                if (ret || thislen != vecs[i].iov_len)
1018                        break;
1019                to += vecs[i].iov_len;
1020        }
1021        *retlen = totlen;
1022        return ret;
1023}
1024
1025/*
1026 * mtd_writev - the vector-based MTD write method
1027 * @mtd: mtd device description object pointer
1028 * @vecs: the vectors to write
1029 * @count: count of vectors in @vecs
1030 * @to: the MTD device offset to write to
1031 * @retlen: on exit contains the count of bytes written to the MTD device.
1032 *
1033 * This function returns zero in case of success and a negative error code in
1034 * case of failure.
1035 */
1036int mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
1037               unsigned long count, loff_t to, size_t *retlen)
1038{
1039        *retlen = 0;
1040        if (!(mtd->flags & MTD_WRITEABLE))
1041                return -EROFS;
1042        if (!mtd->_writev)
1043                return default_mtd_writev(mtd, vecs, count, to, retlen);
1044        return mtd->_writev(mtd, vecs, count, to, retlen);
1045}
1046EXPORT_SYMBOL_GPL(mtd_writev);
1047
1048/**
1049 * mtd_kmalloc_up_to - allocate a contiguous buffer up to the specified size
1050 * @mtd: mtd device description object pointer
1051 * @size: a pointer to the ideal or maximum size of the allocation, points
1052 *        to the actual allocation size on success.
1053 *
1054 * This routine attempts to allocate a contiguous kernel buffer up to
1055 * the specified size, backing off the size of the request exponentially
1056 * until the request succeeds or until the allocation size falls below
1057 * the system page size. This attempts to make sure it does not adversely
1058 * impact system performance, so when allocating more than one page, we
1059 * ask the memory allocator to avoid re-trying, swapping, writing back
1060 * or performing I/O.
1061 *
1062 * Note, this function also makes sure that the allocated buffer is aligned to
1063 * the MTD device's min. I/O unit, i.e. the "mtd->writesize" value.
1064 *
1065 * This is called, for example by mtd_{read,write} and jffs2_scan_medium,
1066 * to handle smaller (i.e. degraded) buffer allocations under low- or
1067 * fragmented-memory situations where such reduced allocations, from a
1068 * requested ideal, are allowed.
1069 *
1070 * Returns a pointer to the allocated buffer on success; otherwise, NULL.
1071 */
1072void *mtd_kmalloc_up_to(const struct mtd_info *mtd, size_t *size)
1073{
1074        gfp_t flags = __GFP_NOWARN | __GFP_WAIT |
1075                       __GFP_NORETRY | __GFP_NO_KSWAPD;
1076        size_t min_alloc = max_t(size_t, mtd->writesize, PAGE_SIZE);
1077        void *kbuf;
1078
1079        *size = min_t(size_t, *size, KMALLOC_MAX_SIZE);
1080
1081        while (*size > min_alloc) {
1082                kbuf = kmalloc(*size, flags);
1083                if (kbuf)
1084                        return kbuf;
1085
1086                *size >>= 1;
1087                *size = ALIGN(*size, mtd->writesize);
1088        }
1089
1090        /*
1091         * For the last resort allocation allow 'kmalloc()' to do all sorts of
1092         * things (write-back, dropping caches, etc) by using GFP_KERNEL.
1093         */
1094        return kmalloc(*size, GFP_KERNEL);
1095}
1096EXPORT_SYMBOL_GPL(mtd_kmalloc_up_to);
1097
1098#ifdef CONFIG_PROC_FS
1099
1100/*====================================================================*/
1101/* Support for /proc/mtd */
1102
1103static struct proc_dir_entry *proc_mtd;
1104
1105static int mtd_proc_show(struct seq_file *m, void *v)
1106{
1107        struct mtd_info *mtd;
1108
1109        seq_puts(m, "dev:    size   erasesize  name\n");
1110        mutex_lock(&mtd_table_mutex);
1111        mtd_for_each_device(mtd) {
1112                seq_printf(m, "mtd%d: %8.8llx %8.8x \"%s\"\n",
1113                           mtd->index, (unsigned long long)mtd->size,
1114                           mtd->erasesize, mtd->name);
1115        }
1116        mutex_unlock(&mtd_table_mutex);
1117        return 0;
1118}
1119
1120static int mtd_proc_open(struct inode *inode, struct file *file)
1121{
1122        return single_open(file, mtd_proc_show, NULL);
1123}
1124
1125static const struct file_operations mtd_proc_ops = {
1126        .open           = mtd_proc_open,
1127        .read           = seq_read,
1128        .llseek         = seq_lseek,
1129        .release        = single_release,
1130};
1131#endif /* CONFIG_PROC_FS */
1132
1133/*====================================================================*/
1134/* Init code */
1135
1136static int __init mtd_bdi_init(struct backing_dev_info *bdi, const char *name)
1137{
1138        int ret;
1139
1140        ret = bdi_init(bdi);
1141        if (!ret)
1142                ret = bdi_register(bdi, NULL, name);
1143
1144        if (ret)
1145                bdi_destroy(bdi);
1146
1147        return ret;
1148}
1149
1150static int __init init_mtd(void)
1151{
1152        int ret;
1153
1154        ret = class_register(&mtd_class);
1155        if (ret)
1156                goto err_reg;
1157
1158        ret = mtd_bdi_init(&mtd_bdi_unmappable, "mtd-unmap");
1159        if (ret)
1160                goto err_bdi1;
1161
1162        ret = mtd_bdi_init(&mtd_bdi_ro_mappable, "mtd-romap");
1163        if (ret)
1164                goto err_bdi2;
1165
1166        ret = mtd_bdi_init(&mtd_bdi_rw_mappable, "mtd-rwmap");
1167        if (ret)
1168                goto err_bdi3;
1169
1170#ifdef CONFIG_PROC_FS
1171        proc_mtd = proc_create("mtd", 0, NULL, &mtd_proc_ops);
1172#endif /* CONFIG_PROC_FS */
1173        return 0;
1174
1175err_bdi3:
1176        bdi_destroy(&mtd_bdi_ro_mappable);
1177err_bdi2:
1178        bdi_destroy(&mtd_bdi_unmappable);
1179err_bdi1:
1180        class_unregister(&mtd_class);
1181err_reg:
1182        pr_err("Error registering mtd class or bdi: %d\n", ret);
1183        return ret;
1184}
1185
1186static void __exit cleanup_mtd(void)
1187{
1188#ifdef CONFIG_PROC_FS
1189        if (proc_mtd)
1190                remove_proc_entry( "mtd", NULL);
1191#endif /* CONFIG_PROC_FS */
1192        class_unregister(&mtd_class);
1193        bdi_destroy(&mtd_bdi_unmappable);
1194        bdi_destroy(&mtd_bdi_ro_mappable);
1195        bdi_destroy(&mtd_bdi_rw_mappable);
1196}
1197
1198module_init(init_mtd);
1199module_exit(cleanup_mtd);
1200
1201MODULE_LICENSE("GPL");
1202MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
1203MODULE_DESCRIPTION("Core MTD registration and access routines");
1204
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