Root/drivers/mtd/mtdcore.c

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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