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#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 ssize_t mtd_ecc_step_size_show(struct device *dev,
 289                struct device_attribute *attr, char *buf)
 290{
 291        struct mtd_info *mtd = dev_get_drvdata(dev);
 292
 293        return snprintf(buf, PAGE_SIZE, "%u\n", mtd->ecc_step_size);
 294
 295}
 296static DEVICE_ATTR(ecc_step_size, S_IRUGO, mtd_ecc_step_size_show, NULL);
 297
 298static struct attribute *mtd_attrs[] = {
 299        &dev_attr_type.attr,
 300        &dev_attr_flags.attr,
 301        &dev_attr_size.attr,
 302        &dev_attr_erasesize.attr,
 303        &dev_attr_writesize.attr,
 304        &dev_attr_subpagesize.attr,
 305        &dev_attr_oobsize.attr,
 306        &dev_attr_numeraseregions.attr,
 307        &dev_attr_name.attr,
 308        &dev_attr_ecc_strength.attr,
 309        &dev_attr_ecc_step_size.attr,
 310        &dev_attr_bitflip_threshold.attr,
 311        NULL,
 312};
 313
 314static struct attribute_group mtd_group = {
 315        .attrs          = mtd_attrs,
 316};
 317
 318static const struct attribute_group *mtd_groups[] = {
 319        &mtd_group,
 320        NULL,
 321};
 322
 323static struct device_type mtd_devtype = {
 324        .name           = "mtd",
 325        .groups         = mtd_groups,
 326        .release        = mtd_release,
 327};
 328
 329/**
 330 *      add_mtd_device - register an MTD device
 331 *      @mtd: pointer to new MTD device info structure
 332 *
 333 *      Add a device to the list of MTD devices present in the system, and
 334 *      notify each currently active MTD 'user' of its arrival. Returns
 335 *      zero on success or 1 on failure, which currently will only happen
 336 *      if there is insufficient memory or a sysfs error.
 337 */
 338
 339int add_mtd_device(struct mtd_info *mtd)
 340{
 341        struct mtd_notifier *not;
 342        int i, error;
 343
 344        if (!mtd->backing_dev_info) {
 345                switch (mtd->type) {
 346                case MTD_RAM:
 347                        mtd->backing_dev_info = &mtd_bdi_rw_mappable;
 348                        break;
 349                case MTD_ROM:
 350                        mtd->backing_dev_info = &mtd_bdi_ro_mappable;
 351                        break;
 352                default:
 353                        mtd->backing_dev_info = &mtd_bdi_unmappable;
 354                        break;
 355                }
 356        }
 357
 358        BUG_ON(mtd->writesize == 0);
 359        mutex_lock(&mtd_table_mutex);
 360
 361        i = idr_alloc(&mtd_idr, mtd, 0, 0, GFP_KERNEL);
 362        if (i < 0)
 363                goto fail_locked;
 364
 365        mtd->index = i;
 366        mtd->usecount = 0;
 367
 368        /* default value if not set by driver */
 369        if (mtd->bitflip_threshold == 0)
 370                mtd->bitflip_threshold = mtd->ecc_strength;
 371
 372        if (is_power_of_2(mtd->erasesize))
 373                mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
 374        else
 375                mtd->erasesize_shift = 0;
 376
 377        if (is_power_of_2(mtd->writesize))
 378                mtd->writesize_shift = ffs(mtd->writesize) - 1;
 379        else
 380                mtd->writesize_shift = 0;
 381
 382        mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
 383        mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
 384
 385        /* Some chips always power up locked. Unlock them now */
 386        if ((mtd->flags & MTD_WRITEABLE) && (mtd->flags & MTD_POWERUP_LOCK)) {
 387                error = mtd_unlock(mtd, 0, mtd->size);
 388                if (error && error != -EOPNOTSUPP)
 389                        printk(KERN_WARNING
 390                               "%s: unlock failed, writes may not work\n",
 391                               mtd->name);
 392        }
 393
 394        /* Caller should have set dev.parent to match the
 395         * physical device.
 396         */
 397        mtd->dev.type = &mtd_devtype;
 398        mtd->dev.class = &mtd_class;
 399        mtd->dev.devt = MTD_DEVT(i);
 400        dev_set_name(&mtd->dev, "mtd%d", i);
 401        dev_set_drvdata(&mtd->dev, mtd);
 402        if (device_register(&mtd->dev) != 0)
 403                goto fail_added;
 404
 405        if (MTD_DEVT(i))
 406                device_create(&mtd_class, mtd->dev.parent,
 407                              MTD_DEVT(i) + 1,
 408                              NULL, "mtd%dro", i);
 409
 410        pr_debug("mtd: Giving out device %d to %s\n", i, mtd->name);
 411        /* No need to get a refcount on the module containing
 412           the notifier, since we hold the mtd_table_mutex */
 413        list_for_each_entry(not, &mtd_notifiers, list)
 414                not->add(mtd);
 415
 416        mutex_unlock(&mtd_table_mutex);
 417        /* We _know_ we aren't being removed, because
 418           our caller is still holding us here. So none
 419           of this try_ nonsense, and no bitching about it
 420           either. :) */
 421        __module_get(THIS_MODULE);
 422        return 0;
 423
 424fail_added:
 425        idr_remove(&mtd_idr, i);
 426fail_locked:
 427        mutex_unlock(&mtd_table_mutex);
 428        return 1;
 429}
 430
 431/**
 432 *      del_mtd_device - unregister an MTD device
 433 *      @mtd: pointer to MTD device info structure
 434 *
 435 *      Remove a device from the list of MTD devices present in the system,
 436 *      and notify each currently active MTD 'user' of its departure.
 437 *      Returns zero on success or 1 on failure, which currently will happen
 438 *      if the requested device does not appear to be present in the list.
 439 */
 440
 441int del_mtd_device(struct mtd_info *mtd)
 442{
 443        int ret;
 444        struct mtd_notifier *not;
 445
 446        mutex_lock(&mtd_table_mutex);
 447
 448        if (idr_find(&mtd_idr, mtd->index) != mtd) {
 449                ret = -ENODEV;
 450                goto out_error;
 451        }
 452
 453        /* No need to get a refcount on the module containing
 454                the notifier, since we hold the mtd_table_mutex */
 455        list_for_each_entry(not, &mtd_notifiers, list)
 456                not->remove(mtd);
 457
 458        if (mtd->usecount) {
 459                printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
 460                       mtd->index, mtd->name, mtd->usecount);
 461                ret = -EBUSY;
 462        } else {
 463                device_unregister(&mtd->dev);
 464
 465                idr_remove(&mtd_idr, mtd->index);
 466
 467                module_put(THIS_MODULE);
 468                ret = 0;
 469        }
 470
 471out_error:
 472        mutex_unlock(&mtd_table_mutex);
 473        return ret;
 474}
 475
 476/**
 477 * mtd_device_parse_register - parse partitions and register an MTD device.
 478 *
 479 * @mtd: the MTD device to register
 480 * @types: the list of MTD partition probes to try, see
 481 *         'parse_mtd_partitions()' for more information
 482 * @parser_data: MTD partition parser-specific data
 483 * @parts: fallback partition information to register, if parsing fails;
 484 *         only valid if %nr_parts > %0
 485 * @nr_parts: the number of partitions in parts, if zero then the full
 486 *            MTD device is registered if no partition info is found
 487 *
 488 * This function aggregates MTD partitions parsing (done by
 489 * 'parse_mtd_partitions()') and MTD device and partitions registering. It
 490 * basically follows the most common pattern found in many MTD drivers:
 491 *
 492 * * It first tries to probe partitions on MTD device @mtd using parsers
 493 *   specified in @types (if @types is %NULL, then the default list of parsers
 494 *   is used, see 'parse_mtd_partitions()' for more information). If none are
 495 *   found this functions tries to fallback to information specified in
 496 *   @parts/@nr_parts.
 497 * * If any partitioning info was found, this function registers the found
 498 *   partitions.
 499 * * If no partitions were found this function just registers the MTD device
 500 *   @mtd and exits.
 501 *
 502 * Returns zero in case of success and a negative error code in case of failure.
 503 */
 504int mtd_device_parse_register(struct mtd_info *mtd, const char * const *types,
 505                              struct mtd_part_parser_data *parser_data,
 506                              const struct mtd_partition *parts,
 507                              int nr_parts)
 508{
 509        int err;
 510        struct mtd_partition *real_parts;
 511
 512        err = parse_mtd_partitions(mtd, types, &real_parts, parser_data);
 513        if (err <= 0 && nr_parts && parts) {
 514                real_parts = kmemdup(parts, sizeof(*parts) * nr_parts,
 515                                     GFP_KERNEL);
 516                if (!real_parts)
 517                        err = -ENOMEM;
 518                else
 519                        err = nr_parts;
 520        }
 521
 522        if (err > 0) {
 523                err = add_mtd_partitions(mtd, real_parts, err);
 524                kfree(real_parts);
 525        } else if (err == 0) {
 526                err = add_mtd_device(mtd);
 527                if (err == 1)
 528                        err = -ENODEV;
 529        }
 530
 531        return err;
 532}
 533EXPORT_SYMBOL_GPL(mtd_device_parse_register);
 534
 535/**
 536 * mtd_device_unregister - unregister an existing MTD device.
 537 *
 538 * @master: the MTD device to unregister.  This will unregister both the master
 539 *          and any partitions if registered.
 540 */
 541int mtd_device_unregister(struct mtd_info *master)
 542{
 543        int err;
 544
 545        err = del_mtd_partitions(master);
 546        if (err)
 547                return err;
 548
 549        if (!device_is_registered(&master->dev))
 550                return 0;
 551
 552        return del_mtd_device(master);
 553}
 554EXPORT_SYMBOL_GPL(mtd_device_unregister);
 555
 556/**
 557 *      register_mtd_user - register a 'user' of MTD devices.
 558 *      @new: pointer to notifier info structure
 559 *
 560 *      Registers a pair of callbacks function to be called upon addition
 561 *      or removal of MTD devices. Causes the 'add' callback to be immediately
 562 *      invoked for each MTD device currently present in the system.
 563 */
 564void register_mtd_user (struct mtd_notifier *new)
 565{
 566        struct mtd_info *mtd;
 567
 568        mutex_lock(&mtd_table_mutex);
 569
 570        list_add(&new->list, &mtd_notifiers);
 571
 572        __module_get(THIS_MODULE);
 573
 574        mtd_for_each_device(mtd)
 575                new->add(mtd);
 576
 577        mutex_unlock(&mtd_table_mutex);
 578}
 579EXPORT_SYMBOL_GPL(register_mtd_user);
 580
 581/**
 582 *      unregister_mtd_user - unregister a 'user' of MTD devices.
 583 *      @old: pointer to notifier info structure
 584 *
 585 *      Removes a callback function pair from the list of 'users' to be
 586 *      notified upon addition or removal of MTD devices. Causes the
 587 *      'remove' callback to be immediately invoked for each MTD device
 588 *      currently present in the system.
 589 */
 590int unregister_mtd_user (struct mtd_notifier *old)
 591{
 592        struct mtd_info *mtd;
 593
 594        mutex_lock(&mtd_table_mutex);
 595
 596        module_put(THIS_MODULE);
 597
 598        mtd_for_each_device(mtd)
 599                old->remove(mtd);
 600
 601        list_del(&old->list);
 602        mutex_unlock(&mtd_table_mutex);
 603        return 0;
 604}
 605EXPORT_SYMBOL_GPL(unregister_mtd_user);
 606
 607/**
 608 *      get_mtd_device - obtain a validated handle for an MTD device
 609 *      @mtd: last known address of the required MTD device
 610 *      @num: internal device number of the required MTD device
 611 *
 612 *      Given a number and NULL address, return the num'th entry in the device
 613 *      table, if any.  Given an address and num == -1, search the device table
 614 *      for a device with that address and return if it's still present. Given
 615 *      both, return the num'th driver only if its address matches. Return
 616 *      error code if not.
 617 */
 618struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
 619{
 620        struct mtd_info *ret = NULL, *other;
 621        int err = -ENODEV;
 622
 623        mutex_lock(&mtd_table_mutex);
 624
 625        if (num == -1) {
 626                mtd_for_each_device(other) {
 627                        if (other == mtd) {
 628                                ret = mtd;
 629                                break;
 630                        }
 631                }
 632        } else if (num >= 0) {
 633                ret = idr_find(&mtd_idr, num);
 634                if (mtd && mtd != ret)
 635                        ret = NULL;
 636        }
 637
 638        if (!ret) {
 639                ret = ERR_PTR(err);
 640                goto out;
 641        }
 642
 643        err = __get_mtd_device(ret);
 644        if (err)
 645                ret = ERR_PTR(err);
 646out:
 647        mutex_unlock(&mtd_table_mutex);
 648        return ret;
 649}
 650EXPORT_SYMBOL_GPL(get_mtd_device);
 651
 652
 653int __get_mtd_device(struct mtd_info *mtd)
 654{
 655        int err;
 656
 657        if (!try_module_get(mtd->owner))
 658                return -ENODEV;
 659
 660        if (mtd->_get_device) {
 661                err = mtd->_get_device(mtd);
 662
 663                if (err) {
 664                        module_put(mtd->owner);
 665                        return err;
 666                }
 667        }
 668        mtd->usecount++;
 669        return 0;
 670}
 671EXPORT_SYMBOL_GPL(__get_mtd_device);
 672
 673/**
 674 *      get_mtd_device_nm - obtain a validated handle for an MTD device by
 675 *      device name
 676 *      @name: MTD device name to open
 677 *
 678 *      This function returns MTD device description structure in case of
 679 *      success and an error code in case of failure.
 680 */
 681struct mtd_info *get_mtd_device_nm(const char *name)
 682{
 683        int err = -ENODEV;
 684        struct mtd_info *mtd = NULL, *other;
 685
 686        mutex_lock(&mtd_table_mutex);
 687
 688        mtd_for_each_device(other) {
 689                if (!strcmp(name, other->name)) {
 690                        mtd = other;
 691                        break;
 692                }
 693        }
 694
 695        if (!mtd)
 696                goto out_unlock;
 697
 698        err = __get_mtd_device(mtd);
 699        if (err)
 700                goto out_unlock;
 701
 702        mutex_unlock(&mtd_table_mutex);
 703        return mtd;
 704
 705out_unlock:
 706        mutex_unlock(&mtd_table_mutex);
 707        return ERR_PTR(err);
 708}
 709EXPORT_SYMBOL_GPL(get_mtd_device_nm);
 710
 711void put_mtd_device(struct mtd_info *mtd)
 712{
 713        mutex_lock(&mtd_table_mutex);
 714        __put_mtd_device(mtd);
 715        mutex_unlock(&mtd_table_mutex);
 716
 717}
 718EXPORT_SYMBOL_GPL(put_mtd_device);
 719
 720void __put_mtd_device(struct mtd_info *mtd)
 721{
 722        --mtd->usecount;
 723        BUG_ON(mtd->usecount < 0);
 724
 725        if (mtd->_put_device)
 726                mtd->_put_device(mtd);
 727
 728        module_put(mtd->owner);
 729}
 730EXPORT_SYMBOL_GPL(__put_mtd_device);
 731
 732/*
 733 * Erase is an asynchronous operation.  Device drivers are supposed
 734 * to call instr->callback() whenever the operation completes, even
 735 * if it completes with a failure.
 736 * Callers are supposed to pass a callback function and wait for it
 737 * to be called before writing to the block.
 738 */
 739int mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
 740{
 741        if (instr->addr > mtd->size || instr->len > mtd->size - instr->addr)
 742                return -EINVAL;
 743        if (!(mtd->flags & MTD_WRITEABLE))
 744                return -EROFS;
 745        instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
 746        if (!instr->len) {
 747                instr->state = MTD_ERASE_DONE;
 748                mtd_erase_callback(instr);
 749                return 0;
 750        }
 751        return mtd->_erase(mtd, instr);
 752}
 753EXPORT_SYMBOL_GPL(mtd_erase);
 754
 755/*
 756 * This stuff for eXecute-In-Place. phys is optional and may be set to NULL.
 757 */
 758int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
 759              void **virt, resource_size_t *phys)
 760{
 761        *retlen = 0;
 762        *virt = NULL;
 763        if (phys)
 764                *phys = 0;
 765        if (!mtd->_point)
 766                return -EOPNOTSUPP;
 767        if (from < 0 || from > mtd->size || len > mtd->size - from)
 768                return -EINVAL;
 769        if (!len)
 770                return 0;
 771        return mtd->_point(mtd, from, len, retlen, virt, phys);
 772}
 773EXPORT_SYMBOL_GPL(mtd_point);
 774
 775/* We probably shouldn't allow XIP if the unpoint isn't a NULL */
 776int mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
 777{
 778        if (!mtd->_point)
 779                return -EOPNOTSUPP;
 780        if (from < 0 || from > mtd->size || len > mtd->size - from)
 781                return -EINVAL;
 782        if (!len)
 783                return 0;
 784        return mtd->_unpoint(mtd, from, len);
 785}
 786EXPORT_SYMBOL_GPL(mtd_unpoint);
 787
 788/*
 789 * Allow NOMMU mmap() to directly map the device (if not NULL)
 790 * - return the address to which the offset maps
 791 * - return -ENOSYS to indicate refusal to do the mapping
 792 */
 793unsigned long mtd_get_unmapped_area(struct mtd_info *mtd, unsigned long len,
 794                                    unsigned long offset, unsigned long flags)
 795{
 796        if (!mtd->_get_unmapped_area)
 797                return -EOPNOTSUPP;
 798        if (offset > mtd->size || len > mtd->size - offset)
 799                return -EINVAL;
 800        return mtd->_get_unmapped_area(mtd, len, offset, flags);
 801}
 802EXPORT_SYMBOL_GPL(mtd_get_unmapped_area);
 803
 804int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
 805             u_char *buf)
 806{
 807        int ret_code;
 808        *retlen = 0;
 809        if (from < 0 || from > mtd->size || len > mtd->size - from)
 810                return -EINVAL;
 811        if (!len)
 812                return 0;
 813
 814        /*
 815         * In the absence of an error, drivers return a non-negative integer
 816         * representing the maximum number of bitflips that were corrected on
 817         * any one ecc region (if applicable; zero otherwise).
 818         */
 819        ret_code = mtd->_read(mtd, from, len, retlen, buf);
 820        if (unlikely(ret_code < 0))
 821                return ret_code;
 822        if (mtd->ecc_strength == 0)
 823                return 0;       /* device lacks ecc */
 824        return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
 825}
 826EXPORT_SYMBOL_GPL(mtd_read);
 827
 828int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
 829              const u_char *buf)
 830{
 831        *retlen = 0;
 832        if (to < 0 || to > mtd->size || len > mtd->size - to)
 833                return -EINVAL;
 834        if (!mtd->_write || !(mtd->flags & MTD_WRITEABLE))
 835                return -EROFS;
 836        if (!len)
 837                return 0;
 838        return mtd->_write(mtd, to, len, retlen, buf);
 839}
 840EXPORT_SYMBOL_GPL(mtd_write);
 841
 842/*
 843 * In blackbox flight recorder like scenarios we want to make successful writes
 844 * in interrupt context. panic_write() is only intended to be called when its
 845 * known the kernel is about to panic and we need the write to succeed. Since
 846 * the kernel is not going to be running for much longer, this function can
 847 * break locks and delay to ensure the write succeeds (but not sleep).
 848 */
 849int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
 850                    const u_char *buf)
 851{
 852        *retlen = 0;
 853        if (!mtd->_panic_write)
 854                return -EOPNOTSUPP;
 855        if (to < 0 || to > mtd->size || len > mtd->size - to)
 856                return -EINVAL;
 857        if (!(mtd->flags & MTD_WRITEABLE))
 858                return -EROFS;
 859        if (!len)
 860                return 0;
 861        return mtd->_panic_write(mtd, to, len, retlen, buf);
 862}
 863EXPORT_SYMBOL_GPL(mtd_panic_write);
 864
 865int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
 866{
 867        int ret_code;
 868        ops->retlen = ops->oobretlen = 0;
 869        if (!mtd->_read_oob)
 870                return -EOPNOTSUPP;
 871        /*
 872         * In cases where ops->datbuf != NULL, mtd->_read_oob() has semantics
 873         * similar to mtd->_read(), returning a non-negative integer
 874         * representing max bitflips. In other cases, mtd->_read_oob() may
 875         * return -EUCLEAN. In all cases, perform similar logic to mtd_read().
 876         */
 877        ret_code = mtd->_read_oob(mtd, from, ops);
 878        if (unlikely(ret_code < 0))
 879                return ret_code;
 880        if (mtd->ecc_strength == 0)
 881                return 0;       /* device lacks ecc */
 882        return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
 883}
 884EXPORT_SYMBOL_GPL(mtd_read_oob);
 885
 886/*
 887 * Method to access the protection register area, present in some flash
 888 * devices. The user data is one time programmable but the factory data is read
 889 * only.
 890 */
 891int mtd_get_fact_prot_info(struct mtd_info *mtd, struct otp_info *buf,
 892                           size_t len)
 893{
 894        if (!mtd->_get_fact_prot_info)
 895                return -EOPNOTSUPP;
 896        if (!len)
 897                return 0;
 898        return mtd->_get_fact_prot_info(mtd, buf, len);
 899}
 900EXPORT_SYMBOL_GPL(mtd_get_fact_prot_info);
 901
 902int mtd_read_fact_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
 903                           size_t *retlen, u_char *buf)
 904{
 905        *retlen = 0;
 906        if (!mtd->_read_fact_prot_reg)
 907                return -EOPNOTSUPP;
 908        if (!len)
 909                return 0;
 910        return mtd->_read_fact_prot_reg(mtd, from, len, retlen, buf);
 911}
 912EXPORT_SYMBOL_GPL(mtd_read_fact_prot_reg);
 913
 914int mtd_get_user_prot_info(struct mtd_info *mtd, struct otp_info *buf,
 915                           size_t len)
 916{
 917        if (!mtd->_get_user_prot_info)
 918                return -EOPNOTSUPP;
 919        if (!len)
 920                return 0;
 921        return mtd->_get_user_prot_info(mtd, buf, len);
 922}
 923EXPORT_SYMBOL_GPL(mtd_get_user_prot_info);
 924
 925int mtd_read_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
 926                           size_t *retlen, u_char *buf)
 927{
 928        *retlen = 0;
 929        if (!mtd->_read_user_prot_reg)
 930                return -EOPNOTSUPP;
 931        if (!len)
 932                return 0;
 933        return mtd->_read_user_prot_reg(mtd, from, len, retlen, buf);
 934}
 935EXPORT_SYMBOL_GPL(mtd_read_user_prot_reg);
 936
 937int mtd_write_user_prot_reg(struct mtd_info *mtd, loff_t to, size_t len,
 938                            size_t *retlen, u_char *buf)
 939{
 940        *retlen = 0;
 941        if (!mtd->_write_user_prot_reg)
 942                return -EOPNOTSUPP;
 943        if (!len)
 944                return 0;
 945        return mtd->_write_user_prot_reg(mtd, to, len, retlen, buf);
 946}
 947EXPORT_SYMBOL_GPL(mtd_write_user_prot_reg);
 948
 949int mtd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len)
 950{
 951        if (!mtd->_lock_user_prot_reg)
 952                return -EOPNOTSUPP;
 953        if (!len)
 954                return 0;
 955        return mtd->_lock_user_prot_reg(mtd, from, len);
 956}
 957EXPORT_SYMBOL_GPL(mtd_lock_user_prot_reg);
 958
 959/* Chip-supported device locking */
 960int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 961{
 962        if (!mtd->_lock)
 963                return -EOPNOTSUPP;
 964        if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
 965                return -EINVAL;
 966        if (!len)
 967                return 0;
 968        return mtd->_lock(mtd, ofs, len);
 969}
 970EXPORT_SYMBOL_GPL(mtd_lock);
 971
 972int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 973{
 974        if (!mtd->_unlock)
 975                return -EOPNOTSUPP;
 976        if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
 977                return -EINVAL;
 978        if (!len)
 979                return 0;
 980        return mtd->_unlock(mtd, ofs, len);
 981}
 982EXPORT_SYMBOL_GPL(mtd_unlock);
 983
 984int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 985{
 986        if (!mtd->_is_locked)
 987                return -EOPNOTSUPP;
 988        if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
 989                return -EINVAL;
 990        if (!len)
 991                return 0;
 992        return mtd->_is_locked(mtd, ofs, len);
 993}
 994EXPORT_SYMBOL_GPL(mtd_is_locked);
 995
 996int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs)
 997{
 998        if (!mtd->_block_isbad)
 999                return 0;
1000        if (ofs < 0 || ofs > mtd->size)
1001                return -EINVAL;
1002        return mtd->_block_isbad(mtd, ofs);
1003}
1004EXPORT_SYMBOL_GPL(mtd_block_isbad);
1005
1006int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs)
1007{
1008        if (!mtd->_block_markbad)
1009                return -EOPNOTSUPP;
1010        if (ofs < 0 || ofs > mtd->size)
1011                return -EINVAL;
1012        if (!(mtd->flags & MTD_WRITEABLE))
1013                return -EROFS;
1014        return mtd->_block_markbad(mtd, ofs);
1015}
1016EXPORT_SYMBOL_GPL(mtd_block_markbad);
1017
1018/*
1019 * default_mtd_writev - the default writev method
1020 * @mtd: mtd device description object pointer
1021 * @vecs: the vectors to write
1022 * @count: count of vectors in @vecs
1023 * @to: the MTD device offset to write to
1024 * @retlen: on exit contains the count of bytes written to the MTD device.
1025 *
1026 * This function returns zero in case of success and a negative error code in
1027 * case of failure.
1028 */
1029static int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
1030                              unsigned long count, loff_t to, size_t *retlen)
1031{
1032        unsigned long i;
1033        size_t totlen = 0, thislen;
1034        int ret = 0;
1035
1036        for (i = 0; i < count; i++) {
1037                if (!vecs[i].iov_len)
1038                        continue;
1039                ret = mtd_write(mtd, to, vecs[i].iov_len, &thislen,
1040                                vecs[i].iov_base);
1041                totlen += thislen;
1042                if (ret || thislen != vecs[i].iov_len)
1043                        break;
1044                to += vecs[i].iov_len;
1045        }
1046        *retlen = totlen;
1047        return ret;
1048}
1049
1050/*
1051 * mtd_writev - the vector-based MTD write method
1052 * @mtd: mtd device description object pointer
1053 * @vecs: the vectors to write
1054 * @count: count of vectors in @vecs
1055 * @to: the MTD device offset to write to
1056 * @retlen: on exit contains the count of bytes written to the MTD device.
1057 *
1058 * This function returns zero in case of success and a negative error code in
1059 * case of failure.
1060 */
1061int mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
1062               unsigned long count, loff_t to, size_t *retlen)
1063{
1064        *retlen = 0;
1065        if (!(mtd->flags & MTD_WRITEABLE))
1066                return -EROFS;
1067        if (!mtd->_writev)
1068                return default_mtd_writev(mtd, vecs, count, to, retlen);
1069        return mtd->_writev(mtd, vecs, count, to, retlen);
1070}
1071EXPORT_SYMBOL_GPL(mtd_writev);
1072
1073/**
1074 * mtd_kmalloc_up_to - allocate a contiguous buffer up to the specified size
1075 * @mtd: mtd device description object pointer
1076 * @size: a pointer to the ideal or maximum size of the allocation, points
1077 *        to the actual allocation size on success.
1078 *
1079 * This routine attempts to allocate a contiguous kernel buffer up to
1080 * the specified size, backing off the size of the request exponentially
1081 * until the request succeeds or until the allocation size falls below
1082 * the system page size. This attempts to make sure it does not adversely
1083 * impact system performance, so when allocating more than one page, we
1084 * ask the memory allocator to avoid re-trying, swapping, writing back
1085 * or performing I/O.
1086 *
1087 * Note, this function also makes sure that the allocated buffer is aligned to
1088 * the MTD device's min. I/O unit, i.e. the "mtd->writesize" value.
1089 *
1090 * This is called, for example by mtd_{read,write} and jffs2_scan_medium,
1091 * to handle smaller (i.e. degraded) buffer allocations under low- or
1092 * fragmented-memory situations where such reduced allocations, from a
1093 * requested ideal, are allowed.
1094 *
1095 * Returns a pointer to the allocated buffer on success; otherwise, NULL.
1096 */
1097void *mtd_kmalloc_up_to(const struct mtd_info *mtd, size_t *size)
1098{
1099        gfp_t flags = __GFP_NOWARN | __GFP_WAIT |
1100                       __GFP_NORETRY | __GFP_NO_KSWAPD;
1101        size_t min_alloc = max_t(size_t, mtd->writesize, PAGE_SIZE);
1102        void *kbuf;
1103
1104        *size = min_t(size_t, *size, KMALLOC_MAX_SIZE);
1105
1106        while (*size > min_alloc) {
1107                kbuf = kmalloc(*size, flags);
1108                if (kbuf)
1109                        return kbuf;
1110
1111                *size >>= 1;
1112                *size = ALIGN(*size, mtd->writesize);
1113        }
1114
1115        /*
1116         * For the last resort allocation allow 'kmalloc()' to do all sorts of
1117         * things (write-back, dropping caches, etc) by using GFP_KERNEL.
1118         */
1119        return kmalloc(*size, GFP_KERNEL);
1120}
1121EXPORT_SYMBOL_GPL(mtd_kmalloc_up_to);
1122
1123#ifdef CONFIG_PROC_FS
1124
1125/*====================================================================*/
1126/* Support for /proc/mtd */
1127
1128static int mtd_proc_show(struct seq_file *m, void *v)
1129{
1130        struct mtd_info *mtd;
1131
1132        seq_puts(m, "dev:    size   erasesize  name\n");
1133        mutex_lock(&mtd_table_mutex);
1134        mtd_for_each_device(mtd) {
1135                seq_printf(m, "mtd%d: %8.8llx %8.8x \"%s\"\n",
1136                           mtd->index, (unsigned long long)mtd->size,
1137                           mtd->erasesize, mtd->name);
1138        }
1139        mutex_unlock(&mtd_table_mutex);
1140        return 0;
1141}
1142
1143static int mtd_proc_open(struct inode *inode, struct file *file)
1144{
1145        return single_open(file, mtd_proc_show, NULL);
1146}
1147
1148static const struct file_operations mtd_proc_ops = {
1149        .open           = mtd_proc_open,
1150        .read           = seq_read,
1151        .llseek         = seq_lseek,
1152        .release        = single_release,
1153};
1154#endif /* CONFIG_PROC_FS */
1155
1156/*====================================================================*/
1157/* Init code */
1158
1159static int __init mtd_bdi_init(struct backing_dev_info *bdi, const char *name)
1160{
1161        int ret;
1162
1163        ret = bdi_init(bdi);
1164        if (!ret)
1165                ret = bdi_register(bdi, NULL, "%s", name);
1166
1167        if (ret)
1168                bdi_destroy(bdi);
1169
1170        return ret;
1171}
1172
1173static struct proc_dir_entry *proc_mtd;
1174
1175static int __init init_mtd(void)
1176{
1177        int ret;
1178
1179        ret = class_register(&mtd_class);
1180        if (ret)
1181                goto err_reg;
1182
1183        ret = mtd_bdi_init(&mtd_bdi_unmappable, "mtd-unmap");
1184        if (ret)
1185                goto err_bdi1;
1186
1187        ret = mtd_bdi_init(&mtd_bdi_ro_mappable, "mtd-romap");
1188        if (ret)
1189                goto err_bdi2;
1190
1191        ret = mtd_bdi_init(&mtd_bdi_rw_mappable, "mtd-rwmap");
1192        if (ret)
1193                goto err_bdi3;
1194
1195        proc_mtd = proc_create("mtd", 0, NULL, &mtd_proc_ops);
1196
1197        ret = init_mtdchar();
1198        if (ret)
1199                goto out_procfs;
1200
1201        return 0;
1202
1203out_procfs:
1204        if (proc_mtd)
1205                remove_proc_entry("mtd", NULL);
1206err_bdi3:
1207        bdi_destroy(&mtd_bdi_ro_mappable);
1208err_bdi2:
1209        bdi_destroy(&mtd_bdi_unmappable);
1210err_bdi1:
1211        class_unregister(&mtd_class);
1212err_reg:
1213        pr_err("Error registering mtd class or bdi: %d\n", ret);
1214        return ret;
1215}
1216
1217static void __exit cleanup_mtd(void)
1218{
1219        cleanup_mtdchar();
1220        if (proc_mtd)
1221                remove_proc_entry("mtd", NULL);
1222        class_unregister(&mtd_class);
1223        bdi_destroy(&mtd_bdi_unmappable);
1224        bdi_destroy(&mtd_bdi_ro_mappable);
1225        bdi_destroy(&mtd_bdi_rw_mappable);
1226}
1227
1228module_init(init_mtd);
1229module_exit(cleanup_mtd);
1230
1231MODULE_LICENSE("GPL");
1232MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
1233MODULE_DESCRIPTION("Core MTD registration and access routines");
1234
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