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  • only in /asuswrt-rt-n18u-9.0.0.4.380.2695/release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/mtd/ubi/
1/*
2 * Copyright (c) International Business Machines Corp., 2006
3 * Copyright (c) Nokia Corporation, 2007
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13 * the GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 * Author: Artem Bityutskiy (���������������� ����������),
20 *         Frank Haverkamp
21 */
22
23/*
24 * This file includes UBI initialization and building of UBI devices.
25 *
26 * When UBI is initialized, it attaches all the MTD devices specified as the
27 * module load parameters or the kernel boot parameters. If MTD devices were
28 * specified, UBI does not attach any MTD device, but it is possible to do
29 * later using the "UBI control device".
30 *
31 * At the moment we only attach UBI devices by scanning, which will become a
32 * bottleneck when flashes reach certain large size. Then one may improve UBI
33 * and add other methods, although it does not seem to be easy to do.
34 */
35
36#include <linux/err.h>
37#include <linux/module.h>
38#include <linux/moduleparam.h>
39#include <linux/stringify.h>
40#include <linux/namei.h>
41#include <linux/stat.h>
42#include <linux/miscdevice.h>
43#include <linux/log2.h>
44#include <linux/kthread.h>
45#include <linux/kernel.h>
46#include <linux/slab.h>
47#include "ubi.h"
48
49/* Maximum length of the 'mtd=' parameter */
50#define MTD_PARAM_LEN_MAX 64
51
52#ifdef CONFIG_MTD_UBI_MODULE
53#define ubi_is_module() 1
54#else
55#define ubi_is_module() 0
56#endif
57
58/**
59 * struct mtd_dev_param - MTD device parameter description data structure.
60 * @name: MTD character device node path, MTD device name, or MTD device number
61 *        string
62 * @vid_hdr_offs: VID header offset
63 */
64struct mtd_dev_param {
65	char name[MTD_PARAM_LEN_MAX];
66	int vid_hdr_offs;
67};
68
69/* Numbers of elements set in the @mtd_dev_param array */
70static int __initdata mtd_devs;
71
72/* MTD devices specification parameters */
73static struct mtd_dev_param __initdata mtd_dev_param[UBI_MAX_DEVICES];
74
75/* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
76struct class *ubi_class;
77
78/* Slab cache for wear-leveling entries */
79struct kmem_cache *ubi_wl_entry_slab;
80
81/* UBI control character device */
82static struct miscdevice ubi_ctrl_cdev = {
83	.minor = MISC_DYNAMIC_MINOR,
84	.name = "ubi_ctrl",
85	.fops = &ubi_ctrl_cdev_operations,
86};
87
88/* All UBI devices in system */
89static struct ubi_device *ubi_devices[UBI_MAX_DEVICES];
90
91/* Serializes UBI devices creations and removals */
92DEFINE_MUTEX(ubi_devices_mutex);
93
94/* Protects @ubi_devices and @ubi->ref_count */
95static DEFINE_SPINLOCK(ubi_devices_lock);
96
97/* "Show" method for files in '/<sysfs>/class/ubi/' */
98static ssize_t ubi_version_show(struct class *class, struct class_attribute *attr,
99				char *buf)
100{
101	return sprintf(buf, "%d\n", UBI_VERSION);
102}
103
104/* UBI version attribute ('/<sysfs>/class/ubi/version') */
105static struct class_attribute ubi_version =
106	__ATTR(version, S_IRUGO, ubi_version_show, NULL);
107
108static ssize_t dev_attribute_show(struct device *dev,
109				  struct device_attribute *attr, char *buf);
110
111/* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
112static struct device_attribute dev_eraseblock_size =
113	__ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
114static struct device_attribute dev_avail_eraseblocks =
115	__ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
116static struct device_attribute dev_total_eraseblocks =
117	__ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
118static struct device_attribute dev_volumes_count =
119	__ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
120static struct device_attribute dev_max_ec =
121	__ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
122static struct device_attribute dev_reserved_for_bad =
123	__ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
124static struct device_attribute dev_bad_peb_count =
125	__ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
126static struct device_attribute dev_max_vol_count =
127	__ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
128static struct device_attribute dev_min_io_size =
129	__ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
130static struct device_attribute dev_bgt_enabled =
131	__ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);
132static struct device_attribute dev_mtd_num =
133	__ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
134
135/**
136 * ubi_volume_notify - send a volume change notification.
137 * @ubi: UBI device description object
138 * @vol: volume description object of the changed volume
139 * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
140 *
141 * This is a helper function which notifies all subscribers about a volume
142 * change event (creation, removal, re-sizing, re-naming, updating). Returns
143 * zero in case of success and a negative error code in case of failure.
144 */
145int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
146{
147	struct ubi_notification nt;
148
149	ubi_do_get_device_info(ubi, &nt.di);
150	ubi_do_get_volume_info(ubi, vol, &nt.vi);
151	return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
152}
153
154/**
155 * ubi_notify_all - send a notification to all volumes.
156 * @ubi: UBI device description object
157 * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
158 * @nb: the notifier to call
159 *
160 * This function walks all volumes of UBI device @ubi and sends the @ntype
161 * notification for each volume. If @nb is %NULL, then all registered notifiers
162 * are called, otherwise only the @nb notifier is called. Returns the number of
163 * sent notifications.
164 */
165int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
166{
167	struct ubi_notification nt;
168	int i, count = 0;
169
170	ubi_do_get_device_info(ubi, &nt.di);
171
172	mutex_lock(&ubi->device_mutex);
173	for (i = 0; i < ubi->vtbl_slots; i++) {
174		/*
175		 * Since the @ubi->device is locked, and we are not going to
176		 * change @ubi->volumes, we do not have to lock
177		 * @ubi->volumes_lock.
178		 */
179		if (!ubi->volumes[i])
180			continue;
181
182		ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
183		if (nb)
184			nb->notifier_call(nb, ntype, &nt);
185		else
186			blocking_notifier_call_chain(&ubi_notifiers, ntype,
187						     &nt);
188		count += 1;
189	}
190	mutex_unlock(&ubi->device_mutex);
191
192	return count;
193}
194
195/**
196 * ubi_enumerate_volumes - send "add" notification for all existing volumes.
197 * @nb: the notifier to call
198 *
199 * This function walks all UBI devices and volumes and sends the
200 * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
201 * registered notifiers are called, otherwise only the @nb notifier is called.
202 * Returns the number of sent notifications.
203 */
204int ubi_enumerate_volumes(struct notifier_block *nb)
205{
206	int i, count = 0;
207
208	/*
209	 * Since the @ubi_devices_mutex is locked, and we are not going to
210	 * change @ubi_devices, we do not have to lock @ubi_devices_lock.
211	 */
212	for (i = 0; i < UBI_MAX_DEVICES; i++) {
213		struct ubi_device *ubi = ubi_devices[i];
214
215		if (!ubi)
216			continue;
217		count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
218	}
219
220	return count;
221}
222
223/**
224 * ubi_get_device - get UBI device.
225 * @ubi_num: UBI device number
226 *
227 * This function returns UBI device description object for UBI device number
228 * @ubi_num, or %NULL if the device does not exist. This function increases the
229 * device reference count to prevent removal of the device. In other words, the
230 * device cannot be removed if its reference count is not zero.
231 */
232struct ubi_device *ubi_get_device(int ubi_num)
233{
234	struct ubi_device *ubi;
235
236	spin_lock(&ubi_devices_lock);
237	ubi = ubi_devices[ubi_num];
238	if (ubi) {
239		ubi_assert(ubi->ref_count >= 0);
240		ubi->ref_count += 1;
241		get_device(&ubi->dev);
242	}
243	spin_unlock(&ubi_devices_lock);
244
245	return ubi;
246}
247
248/**
249 * ubi_put_device - drop an UBI device reference.
250 * @ubi: UBI device description object
251 */
252void ubi_put_device(struct ubi_device *ubi)
253{
254	spin_lock(&ubi_devices_lock);
255	ubi->ref_count -= 1;
256	put_device(&ubi->dev);
257	spin_unlock(&ubi_devices_lock);
258}
259
260/**
261 * ubi_get_by_major - get UBI device by character device major number.
262 * @major: major number
263 *
264 * This function is similar to 'ubi_get_device()', but it searches the device
265 * by its major number.
266 */
267struct ubi_device *ubi_get_by_major(int major)
268{
269	int i;
270	struct ubi_device *ubi;
271
272	spin_lock(&ubi_devices_lock);
273	for (i = 0; i < UBI_MAX_DEVICES; i++) {
274		ubi = ubi_devices[i];
275		if (ubi && MAJOR(ubi->cdev.dev) == major) {
276			ubi_assert(ubi->ref_count >= 0);
277			ubi->ref_count += 1;
278			get_device(&ubi->dev);
279			spin_unlock(&ubi_devices_lock);
280			return ubi;
281		}
282	}
283	spin_unlock(&ubi_devices_lock);
284
285	return NULL;
286}
287
288/**
289 * ubi_major2num - get UBI device number by character device major number.
290 * @major: major number
291 *
292 * This function searches UBI device number object by its major number. If UBI
293 * device was not found, this function returns -ENODEV, otherwise the UBI device
294 * number is returned.
295 */
296int ubi_major2num(int major)
297{
298	int i, ubi_num = -ENODEV;
299
300	spin_lock(&ubi_devices_lock);
301	for (i = 0; i < UBI_MAX_DEVICES; i++) {
302		struct ubi_device *ubi = ubi_devices[i];
303
304		if (ubi && MAJOR(ubi->cdev.dev) == major) {
305			ubi_num = ubi->ubi_num;
306			break;
307		}
308	}
309	spin_unlock(&ubi_devices_lock);
310
311	return ubi_num;
312}
313
314/* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
315static ssize_t dev_attribute_show(struct device *dev,
316				  struct device_attribute *attr, char *buf)
317{
318	ssize_t ret;
319	struct ubi_device *ubi;
320
321	/*
322	 * The below code looks weird, but it actually makes sense. We get the
323	 * UBI device reference from the contained 'struct ubi_device'. But it
324	 * is unclear if the device was removed or not yet. Indeed, if the
325	 * device was removed before we increased its reference count,
326	 * 'ubi_get_device()' will return -ENODEV and we fail.
327	 *
328	 * Remember, 'struct ubi_device' is freed in the release function, so
329	 * we still can use 'ubi->ubi_num'.
330	 */
331	ubi = container_of(dev, struct ubi_device, dev);
332	ubi = ubi_get_device(ubi->ubi_num);
333	if (!ubi)
334		return -ENODEV;
335
336	if (attr == &dev_eraseblock_size)
337		ret = sprintf(buf, "%d\n", ubi->leb_size);
338	else if (attr == &dev_avail_eraseblocks)
339		ret = sprintf(buf, "%d\n", ubi->avail_pebs);
340	else if (attr == &dev_total_eraseblocks)
341		ret = sprintf(buf, "%d\n", ubi->good_peb_count);
342	else if (attr == &dev_volumes_count)
343		ret = sprintf(buf, "%d\n", ubi->vol_count - UBI_INT_VOL_COUNT);
344	else if (attr == &dev_max_ec)
345		ret = sprintf(buf, "%d\n", ubi->max_ec);
346	else if (attr == &dev_reserved_for_bad)
347		ret = sprintf(buf, "%d\n", ubi->beb_rsvd_pebs);
348	else if (attr == &dev_bad_peb_count)
349		ret = sprintf(buf, "%d\n", ubi->bad_peb_count);
350	else if (attr == &dev_max_vol_count)
351		ret = sprintf(buf, "%d\n", ubi->vtbl_slots);
352	else if (attr == &dev_min_io_size)
353		ret = sprintf(buf, "%d\n", ubi->min_io_size);
354	else if (attr == &dev_bgt_enabled)
355		ret = sprintf(buf, "%d\n", ubi->thread_enabled);
356	else if (attr == &dev_mtd_num)
357		ret = sprintf(buf, "%d\n", ubi->mtd->index);
358	else
359		ret = -EINVAL;
360
361	ubi_put_device(ubi);
362	return ret;
363}
364
365static void dev_release(struct device *dev)
366{
367	struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);
368
369	kfree(ubi);
370}
371
372/**
373 * ubi_sysfs_init - initialize sysfs for an UBI device.
374 * @ubi: UBI device description object
375 * @ref: set to %1 on exit in case of failure if a reference to @ubi->dev was
376 *       taken
377 *
378 * This function returns zero in case of success and a negative error code in
379 * case of failure.
380 */
381static int ubi_sysfs_init(struct ubi_device *ubi, int *ref)
382{
383	int err;
384
385	ubi->dev.release = dev_release;
386	ubi->dev.devt = ubi->cdev.dev;
387	ubi->dev.class = ubi_class;
388	dev_set_name(&ubi->dev, UBI_NAME_STR"%d", ubi->ubi_num);
389	err = device_register(&ubi->dev);
390	if (err)
391		return err;
392
393	*ref = 1;
394	err = device_create_file(&ubi->dev, &dev_eraseblock_size);
395	if (err)
396		return err;
397	err = device_create_file(&ubi->dev, &dev_avail_eraseblocks);
398	if (err)
399		return err;
400	err = device_create_file(&ubi->dev, &dev_total_eraseblocks);
401	if (err)
402		return err;
403	err = device_create_file(&ubi->dev, &dev_volumes_count);
404	if (err)
405		return err;
406	err = device_create_file(&ubi->dev, &dev_max_ec);
407	if (err)
408		return err;
409	err = device_create_file(&ubi->dev, &dev_reserved_for_bad);
410	if (err)
411		return err;
412	err = device_create_file(&ubi->dev, &dev_bad_peb_count);
413	if (err)
414		return err;
415	err = device_create_file(&ubi->dev, &dev_max_vol_count);
416	if (err)
417		return err;
418	err = device_create_file(&ubi->dev, &dev_min_io_size);
419	if (err)
420		return err;
421	err = device_create_file(&ubi->dev, &dev_bgt_enabled);
422	if (err)
423		return err;
424	err = device_create_file(&ubi->dev, &dev_mtd_num);
425	return err;
426}
427
428/**
429 * ubi_sysfs_close - close sysfs for an UBI device.
430 * @ubi: UBI device description object
431 */
432static void ubi_sysfs_close(struct ubi_device *ubi)
433{
434	device_remove_file(&ubi->dev, &dev_mtd_num);
435	device_remove_file(&ubi->dev, &dev_bgt_enabled);
436	device_remove_file(&ubi->dev, &dev_min_io_size);
437	device_remove_file(&ubi->dev, &dev_max_vol_count);
438	device_remove_file(&ubi->dev, &dev_bad_peb_count);
439	device_remove_file(&ubi->dev, &dev_reserved_for_bad);
440	device_remove_file(&ubi->dev, &dev_max_ec);
441	device_remove_file(&ubi->dev, &dev_volumes_count);
442	device_remove_file(&ubi->dev, &dev_total_eraseblocks);
443	device_remove_file(&ubi->dev, &dev_avail_eraseblocks);
444	device_remove_file(&ubi->dev, &dev_eraseblock_size);
445	device_unregister(&ubi->dev);
446}
447
448/**
449 * kill_volumes - destroy all user volumes.
450 * @ubi: UBI device description object
451 */
452static void kill_volumes(struct ubi_device *ubi)
453{
454	int i;
455
456	for (i = 0; i < ubi->vtbl_slots; i++)
457		if (ubi->volumes[i])
458			ubi_free_volume(ubi, ubi->volumes[i]);
459}
460
461/**
462 * uif_init - initialize user interfaces for an UBI device.
463 * @ubi: UBI device description object
464 * @ref: set to %1 on exit in case of failure if a reference to @ubi->dev was
465 *       taken, otherwise set to %0
466 *
467 * This function initializes various user interfaces for an UBI device. If the
468 * initialization fails at an early stage, this function frees all the
469 * resources it allocated, returns an error, and @ref is set to %0. However,
470 * if the initialization fails after the UBI device was registered in the
471 * driver core subsystem, this function takes a reference to @ubi->dev, because
472 * otherwise the release function ('dev_release()') would free whole @ubi
473 * object. The @ref argument is set to %1 in this case. The caller has to put
474 * this reference.
475 *
476 * This function returns zero in case of success and a negative error code in
477 * case of failure.
478 */
479static int uif_init(struct ubi_device *ubi, int *ref)
480{
481	int i, err;
482	dev_t dev;
483
484	*ref = 0;
485	sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);
486
487	/*
488	 * Major numbers for the UBI character devices are allocated
489	 * dynamically. Major numbers of volume character devices are
490	 * equivalent to ones of the corresponding UBI character device. Minor
491	 * numbers of UBI character devices are 0, while minor numbers of
492	 * volume character devices start from 1. Thus, we allocate one major
493	 * number and ubi->vtbl_slots + 1 minor numbers.
494	 */
495	err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
496	if (err) {
497		ubi_err("cannot register UBI character devices");
498		return err;
499	}
500
501	ubi_assert(MINOR(dev) == 0);
502	cdev_init(&ubi->cdev, &ubi_cdev_operations);
503	dbg_gen("%s major is %u", ubi->ubi_name, MAJOR(dev));
504	ubi->cdev.owner = THIS_MODULE;
505
506	err = cdev_add(&ubi->cdev, dev, 1);
507	if (err) {
508		ubi_err("cannot add character device");
509		goto out_unreg;
510	}
511
512	err = ubi_sysfs_init(ubi, ref);
513	if (err)
514		goto out_sysfs;
515
516	for (i = 0; i < ubi->vtbl_slots; i++)
517		if (ubi->volumes[i]) {
518			err = ubi_add_volume(ubi, ubi->volumes[i]);
519			if (err) {
520				ubi_err("cannot add volume %d", i);
521				goto out_volumes;
522			}
523		}
524
525	return 0;
526
527out_volumes:
528	kill_volumes(ubi);
529out_sysfs:
530	if (*ref)
531		get_device(&ubi->dev);
532	ubi_sysfs_close(ubi);
533	cdev_del(&ubi->cdev);
534out_unreg:
535	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
536	ubi_err("cannot initialize UBI %s, error %d", ubi->ubi_name, err);
537	return err;
538}
539
540/**
541 * uif_close - close user interfaces for an UBI device.
542 * @ubi: UBI device description object
543 *
544 * Note, since this function un-registers UBI volume device objects (@vol->dev),
545 * the memory allocated voe the volumes is freed as well (in the release
546 * function).
547 */
548static void uif_close(struct ubi_device *ubi)
549{
550	kill_volumes(ubi);
551	ubi_sysfs_close(ubi);
552	cdev_del(&ubi->cdev);
553	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
554}
555
556/**
557 * free_internal_volumes - free internal volumes.
558 * @ubi: UBI device description object
559 */
560static void free_internal_volumes(struct ubi_device *ubi)
561{
562	int i;
563
564	for (i = ubi->vtbl_slots;
565	     i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
566		kfree(ubi->volumes[i]->eba_tbl);
567		kfree(ubi->volumes[i]);
568	}
569}
570
571/**
572 * attach_by_scanning - attach an MTD device using scanning method.
573 * @ubi: UBI device descriptor
574 *
575 * This function returns zero in case of success and a negative error code in
576 * case of failure.
577 *
578 * Note, currently this is the only method to attach UBI devices. Hopefully in
579 * the future we'll have more scalable attaching methods and avoid full media
580 * scanning. But even in this case scanning will be needed as a fall-back
581 * attaching method if there are some on-flash table corruptions.
582 */
583static int attach_by_scanning(struct ubi_device *ubi)
584{
585	int err;
586	struct ubi_scan_info *si;
587
588	si = ubi_scan(ubi);
589	if (IS_ERR(si))
590		return PTR_ERR(si);
591
592	ubi->bad_peb_count = si->bad_peb_count;
593	ubi->good_peb_count = ubi->peb_count - ubi->bad_peb_count;
594	ubi->max_ec = si->max_ec;
595	ubi->mean_ec = si->mean_ec;
596	ubi_msg("max. sequence number:       %llu", si->max_sqnum);
597
598	err = ubi_read_volume_table(ubi, si);
599	if (err)
600		goto out_si;
601
602	err = ubi_wl_init_scan(ubi, si);
603	if (err)
604		goto out_vtbl;
605
606	err = ubi_eba_init_scan(ubi, si);
607	if (err)
608		goto out_wl;
609
610	ubi_scan_destroy_si(si);
611	return 0;
612
613out_wl:
614	ubi_wl_close(ubi);
615out_vtbl:
616	free_internal_volumes(ubi);
617	vfree(ubi->vtbl);
618out_si:
619	ubi_scan_destroy_si(si);
620	return err;
621}
622
623/**
624 * io_init - initialize I/O sub-system for a given UBI device.
625 * @ubi: UBI device description object
626 *
627 * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
628 * assumed:
629 *   o EC header is always at offset zero - this cannot be changed;
630 *   o VID header starts just after the EC header at the closest address
631 *     aligned to @io->hdrs_min_io_size;
632 *   o data starts just after the VID header at the closest address aligned to
633 *     @io->min_io_size
634 *
635 * This function returns zero in case of success and a negative error code in
636 * case of failure.
637 */
638static int io_init(struct ubi_device *ubi)
639{
640	if (ubi->mtd->numeraseregions != 0) {
641		/*
642		 * Some flashes have several erase regions. Different regions
643		 * may have different eraseblock size and other
644		 * characteristics. It looks like mostly multi-region flashes
645		 * have one "main" region and one or more small regions to
646		 * store boot loader code or boot parameters or whatever. I
647		 * guess we should just pick the largest region. But this is
648		 * not implemented.
649		 */
650		ubi_err("multiple regions, not implemented");
651		return -EINVAL;
652	}
653
654	if (ubi->vid_hdr_offset < 0)
655		return -EINVAL;
656
657	/*
658	 * Note, in this implementation we support MTD devices with 0x7FFFFFFF
659	 * physical eraseblocks maximum.
660	 */
661
662	ubi->peb_size   = ubi->mtd->erasesize;
663	ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
664	ubi->flash_size = ubi->mtd->size;
665
666	if (ubi->mtd->block_isbad && ubi->mtd->block_markbad)
667		ubi->bad_allowed = 1;
668
669	if (ubi->mtd->type == MTD_NORFLASH) {
670		ubi_assert(ubi->mtd->writesize == 1);
671		ubi->nor_flash = 1;
672	}
673
674	ubi->min_io_size = ubi->mtd->writesize;
675	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
676
677	/*
678	 * Make sure minimal I/O unit is power of 2. Note, there is no
679	 * fundamental reason for this assumption. It is just an optimization
680	 * which allows us to avoid costly division operations.
681	 */
682	if (!is_power_of_2(ubi->min_io_size)) {
683		ubi_err("min. I/O unit (%d) is not power of 2",
684			ubi->min_io_size);
685		return -EINVAL;
686	}
687
688	ubi_assert(ubi->hdrs_min_io_size > 0);
689	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
690	ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
691
692	/* Calculate default aligned sizes of EC and VID headers */
693	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
694	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
695
696	dbg_msg("min_io_size      %d", ubi->min_io_size);
697	dbg_msg("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
698	dbg_msg("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
699	dbg_msg("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
700
701	if (ubi->vid_hdr_offset == 0)
702		/* Default offset */
703		ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
704				      ubi->ec_hdr_alsize;
705	else {
706		ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
707						~(ubi->hdrs_min_io_size - 1);
708		ubi->vid_hdr_shift = ubi->vid_hdr_offset -
709						ubi->vid_hdr_aloffset;
710	}
711
712	/* Similar for the data offset */
713	ubi->leb_start = ubi->vid_hdr_offset + UBI_EC_HDR_SIZE;
714	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
715
716	dbg_msg("vid_hdr_offset   %d", ubi->vid_hdr_offset);
717	dbg_msg("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
718	dbg_msg("vid_hdr_shift    %d", ubi->vid_hdr_shift);
719	dbg_msg("leb_start        %d", ubi->leb_start);
720
721	/* The shift must be aligned to 32-bit boundary */
722	if (ubi->vid_hdr_shift % 4) {
723		ubi_err("unaligned VID header shift %d",
724			ubi->vid_hdr_shift);
725		return -EINVAL;
726	}
727
728	/* Check sanity */
729	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
730	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
731	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
732	    ubi->leb_start & (ubi->min_io_size - 1)) {
733		ubi_err("bad VID header (%d) or data offsets (%d)",
734			ubi->vid_hdr_offset, ubi->leb_start);
735		return -EINVAL;
736	}
737
738	/*
739	 * Set maximum amount of physical erroneous eraseblocks to be 10%.
740	 * Erroneous PEB are those which have read errors.
741	 */
742	ubi->max_erroneous = ubi->peb_count / 10;
743	if (ubi->max_erroneous < 16)
744		ubi->max_erroneous = 16;
745	dbg_msg("max_erroneous    %d", ubi->max_erroneous);
746
747	/*
748	 * It may happen that EC and VID headers are situated in one minimal
749	 * I/O unit. In this case we can only accept this UBI image in
750	 * read-only mode.
751	 */
752	if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
753		ubi_warn("EC and VID headers are in the same minimal I/O unit, "
754			 "switch to read-only mode");
755		ubi->ro_mode = 1;
756	}
757
758	ubi->leb_size = ubi->peb_size - ubi->leb_start;
759
760	if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
761		ubi_msg("MTD device %d is write-protected, attach in "
762			"read-only mode", ubi->mtd->index);
763		ubi->ro_mode = 1;
764	}
765
766	ubi_msg("physical eraseblock size:   %d bytes (%d KiB)",
767		ubi->peb_size, ubi->peb_size >> 10);
768	ubi_msg("logical eraseblock size:    %d bytes", ubi->leb_size);
769	ubi_msg("smallest flash I/O unit:    %d", ubi->min_io_size);
770	if (ubi->hdrs_min_io_size != ubi->min_io_size)
771		ubi_msg("sub-page size:              %d",
772			ubi->hdrs_min_io_size);
773	ubi_msg("VID header offset:          %d (aligned %d)",
774		ubi->vid_hdr_offset, ubi->vid_hdr_aloffset);
775	ubi_msg("data offset:                %d", ubi->leb_start);
776
777	/*
778	 * Note, ideally, we have to initialize ubi->bad_peb_count here. But
779	 * unfortunately, MTD does not provide this information. We should loop
780	 * over all physical eraseblocks and invoke mtd->block_is_bad() for
781	 * each physical eraseblock. So, we skip ubi->bad_peb_count
782	 * uninitialized and initialize it after scanning.
783	 */
784
785	return 0;
786}
787
788/**
789 * autoresize - re-size the volume which has the "auto-resize" flag set.
790 * @ubi: UBI device description object
791 * @vol_id: ID of the volume to re-size
792 *
793 * This function re-sizes the volume marked by the @UBI_VTBL_AUTORESIZE_FLG in
794 * the volume table to the largest possible size. See comments in ubi-header.h
795 * for more description of the flag. Returns zero in case of success and a
796 * negative error code in case of failure.
797 */
798static int autoresize(struct ubi_device *ubi, int vol_id)
799{
800	struct ubi_volume_desc desc;
801	struct ubi_volume *vol = ubi->volumes[vol_id];
802	int err, old_reserved_pebs = vol->reserved_pebs;
803
804	/*
805	 * Clear the auto-resize flag in the volume in-memory copy of the
806	 * volume table, and 'ubi_resize_volume()' will propagate this change
807	 * to the flash.
808	 */
809	ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;
810
811	if (ubi->avail_pebs == 0) {
812		struct ubi_vtbl_record vtbl_rec;
813
814		/*
815		 * No available PEBs to re-size the volume, clear the flag on
816		 * flash and exit.
817		 */
818		memcpy(&vtbl_rec, &ubi->vtbl[vol_id],
819		       sizeof(struct ubi_vtbl_record));
820		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
821		if (err)
822			ubi_err("cannot clean auto-resize flag for volume %d",
823				vol_id);
824	} else {
825		desc.vol = vol;
826		err = ubi_resize_volume(&desc,
827					old_reserved_pebs + ubi->avail_pebs);
828		if (err)
829			ubi_err("cannot auto-resize volume %d", vol_id);
830	}
831
832	if (err)
833		return err;
834
835	ubi_msg("volume %d (\"%s\") re-sized from %d to %d LEBs", vol_id,
836		vol->name, old_reserved_pebs, vol->reserved_pebs);
837	return 0;
838}
839
840/**
841 * ubi_attach_mtd_dev - attach an MTD device.
842 * @mtd: MTD device description object
843 * @ubi_num: number to assign to the new UBI device
844 * @vid_hdr_offset: VID header offset
845 *
846 * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
847 * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
848 * which case this function finds a vacant device number and assigns it
849 * automatically. Returns the new UBI device number in case of success and a
850 * negative error code in case of failure.
851 *
852 * Note, the invocations of this function has to be serialized by the
853 * @ubi_devices_mutex.
854 */
855int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset)
856{
857	struct ubi_device *ubi;
858	int i, err, ref = 0;
859
860	/*
861	 * Check if we already have the same MTD device attached.
862	 *
863	 * Note, this function assumes that UBI devices creations and deletions
864	 * are serialized, so it does not take the &ubi_devices_lock.
865	 */
866	for (i = 0; i < UBI_MAX_DEVICES; i++) {
867		ubi = ubi_devices[i];
868		if (ubi && mtd->index == ubi->mtd->index) {
869			dbg_err("mtd%d is already attached to ubi%d",
870				mtd->index, i);
871			return -EEXIST;
872		}
873	}
874
875	/*
876	 * Make sure this MTD device is not emulated on top of an UBI volume
877	 * already. Well, generally this recursion works fine, but there are
878	 * different problems like the UBI module takes a reference to itself
879	 * by attaching (and thus, opening) the emulated MTD device. This
880	 * results in inability to unload the module. And in general it makes
881	 * no sense to attach emulated MTD devices, so we prohibit this.
882	 */
883	if (mtd->type == MTD_UBIVOLUME) {
884		ubi_err("refuse attaching mtd%d - it is already emulated on "
885			"top of UBI", mtd->index);
886		return -EINVAL;
887	}
888
889	if (ubi_num == UBI_DEV_NUM_AUTO) {
890		/* Search for an empty slot in the @ubi_devices array */
891		for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
892			if (!ubi_devices[ubi_num])
893				break;
894		if (ubi_num == UBI_MAX_DEVICES) {
895			dbg_err("only %d UBI devices may be created",
896				UBI_MAX_DEVICES);
897			return -ENFILE;
898		}
899	} else {
900		if (ubi_num >= UBI_MAX_DEVICES)
901			return -EINVAL;
902
903		/* Make sure ubi_num is not busy */
904		if (ubi_devices[ubi_num]) {
905			dbg_err("ubi%d already exists", ubi_num);
906			return -EEXIST;
907		}
908	}
909
910	ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
911	if (!ubi)
912		return -ENOMEM;
913
914	ubi->mtd = mtd;
915	ubi->ubi_num = ubi_num;
916	ubi->vid_hdr_offset = vid_hdr_offset;
917	ubi->autoresize_vol_id = -1;
918
919	mutex_init(&ubi->buf_mutex);
920	mutex_init(&ubi->ckvol_mutex);
921	mutex_init(&ubi->device_mutex);
922	spin_lock_init(&ubi->volumes_lock);
923
924	ubi_msg("attaching mtd%d to ubi%d", mtd->index, ubi_num);
925
926	err = io_init(ubi);
927	if (err)
928		goto out_free;
929
930	err = -ENOMEM;
931	ubi->peb_buf1 = vmalloc(ubi->peb_size);
932	if (!ubi->peb_buf1)
933		goto out_free;
934
935	ubi->peb_buf2 = vmalloc(ubi->peb_size);
936	if (!ubi->peb_buf2)
937		goto out_free;
938
939#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
940	mutex_init(&ubi->dbg_buf_mutex);
941	ubi->dbg_peb_buf = vmalloc(ubi->peb_size);
942	if (!ubi->dbg_peb_buf)
943		goto out_free;
944#endif
945
946	err = attach_by_scanning(ubi);
947	if (err) {
948		dbg_err("failed to attach by scanning, error %d", err);
949		goto out_free;
950	}
951
952	if (ubi->autoresize_vol_id != -1) {
953		err = autoresize(ubi, ubi->autoresize_vol_id);
954		if (err)
955			goto out_detach;
956	}
957
958	err = uif_init(ubi, &ref);
959	if (err)
960		goto out_detach;
961
962	ubi->bgt_thread = kthread_create(ubi_thread, ubi, ubi->bgt_name);
963	if (IS_ERR(ubi->bgt_thread)) {
964		err = PTR_ERR(ubi->bgt_thread);
965		ubi_err("cannot spawn \"%s\", error %d", ubi->bgt_name,
966			err);
967		goto out_uif;
968	}
969
970	ubi_msg("attached mtd%d to ubi%d", mtd->index, ubi_num);
971	ubi_msg("MTD device name:            \"%s\"", mtd->name);
972	ubi_msg("MTD device size:            %llu MiB", ubi->flash_size >> 20);
973	ubi_msg("number of good PEBs:        %d", ubi->good_peb_count);
974	ubi_msg("number of bad PEBs:         %d", ubi->bad_peb_count);
975	ubi_msg("max. allowed volumes:       %d", ubi->vtbl_slots);
976	ubi_msg("wear-leveling threshold:    %d", CONFIG_MTD_UBI_WL_THRESHOLD);
977	ubi_msg("number of internal volumes: %d", UBI_INT_VOL_COUNT);
978	ubi_msg("number of user volumes:     %d",
979		ubi->vol_count - UBI_INT_VOL_COUNT);
980	ubi_msg("available PEBs:             %d", ubi->avail_pebs);
981	ubi_msg("total number of reserved PEBs: %d", ubi->rsvd_pebs);
982	ubi_msg("number of PEBs reserved for bad PEB handling: %d",
983		ubi->beb_rsvd_pebs);
984	ubi_msg("max/mean erase counter: %d/%d", ubi->max_ec, ubi->mean_ec);
985	ubi_msg("image sequence number:  %d", ubi->image_seq);
986
987	/*
988	 * The below lock makes sure we do not race with 'ubi_thread()' which
989	 * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
990	 */
991	spin_lock(&ubi->wl_lock);
992	if (!DBG_DISABLE_BGT)
993		ubi->thread_enabled = 1;
994	wake_up_process(ubi->bgt_thread);
995	spin_unlock(&ubi->wl_lock);
996
997	ubi_devices[ubi_num] = ubi;
998	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
999	return ubi_num;
1000
1001out_uif:
1002	uif_close(ubi);
1003out_detach:
1004	ubi_wl_close(ubi);
1005	free_internal_volumes(ubi);
1006	vfree(ubi->vtbl);
1007out_free:
1008	vfree(ubi->peb_buf1);
1009	vfree(ubi->peb_buf2);
1010#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
1011	vfree(ubi->dbg_peb_buf);
1012#endif
1013	if (ref)
1014		put_device(&ubi->dev);
1015	else
1016		kfree(ubi);
1017	return err;
1018}
1019
1020/**
1021 * ubi_detach_mtd_dev - detach an MTD device.
1022 * @ubi_num: UBI device number to detach from
1023 * @anyway: detach MTD even if device reference count is not zero
1024 *
1025 * This function destroys an UBI device number @ubi_num and detaches the
1026 * underlying MTD device. Returns zero in case of success and %-EBUSY if the
1027 * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
1028 * exist.
1029 *
1030 * Note, the invocations of this function has to be serialized by the
1031 * @ubi_devices_mutex.
1032 */
1033int ubi_detach_mtd_dev(int ubi_num, int anyway)
1034{
1035	struct ubi_device *ubi;
1036
1037	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
1038		return -EINVAL;
1039
1040	ubi = ubi_get_device(ubi_num);
1041	if (!ubi)
1042		return -EINVAL;
1043
1044	spin_lock(&ubi_devices_lock);
1045	put_device(&ubi->dev);
1046	ubi->ref_count -= 1;
1047	if (ubi->ref_count) {
1048		if (!anyway) {
1049			spin_unlock(&ubi_devices_lock);
1050			return -EBUSY;
1051		}
1052		/* This may only happen if there is a bug */
1053		ubi_err("%s reference count %d, destroy anyway",
1054			ubi->ubi_name, ubi->ref_count);
1055	}
1056	ubi_devices[ubi_num] = NULL;
1057	spin_unlock(&ubi_devices_lock);
1058
1059	ubi_assert(ubi_num == ubi->ubi_num);
1060	ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
1061	dbg_msg("detaching mtd%d from ubi%d", ubi->mtd->index, ubi_num);
1062
1063	/*
1064	 * Before freeing anything, we have to stop the background thread to
1065	 * prevent it from doing anything on this device while we are freeing.
1066	 */
1067	if (ubi->bgt_thread)
1068		kthread_stop(ubi->bgt_thread);
1069
1070	/*
1071	 * Get a reference to the device in order to prevent 'dev_release()'
1072	 * from freeing the @ubi object.
1073	 */
1074	get_device(&ubi->dev);
1075
1076	uif_close(ubi);
1077	ubi_wl_close(ubi);
1078	free_internal_volumes(ubi);
1079	vfree(ubi->vtbl);
1080	put_mtd_device(ubi->mtd);
1081	vfree(ubi->peb_buf1);
1082	vfree(ubi->peb_buf2);
1083#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
1084	vfree(ubi->dbg_peb_buf);
1085#endif
1086	ubi_msg("mtd%d is detached from ubi%d", ubi->mtd->index, ubi->ubi_num);
1087	put_device(&ubi->dev);
1088	return 0;
1089}
1090
1091/**
1092 * open_mtd_by_chdev - open an MTD device by its character device node path.
1093 * @mtd_dev: MTD character device node path
1094 *
1095 * This helper function opens an MTD device by its character node device path.
1096 * Returns MTD device description object in case of success and a negative
1097 * error code in case of failure.
1098 */
1099static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
1100{
1101	int err, major, minor, mode;
1102	struct path path;
1103
1104	/* Probably this is an MTD character device node path */
1105	err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
1106	if (err)
1107		return ERR_PTR(err);
1108
1109	/* MTD device number is defined by the major / minor numbers */
1110	major = imajor(path.dentry->d_inode);
1111	minor = iminor(path.dentry->d_inode);
1112	mode = path.dentry->d_inode->i_mode;
1113	path_put(&path);
1114	if (major != MTD_CHAR_MAJOR || !S_ISCHR(mode))
1115		return ERR_PTR(-EINVAL);
1116
1117	if (minor & 1)
1118		/*
1119		 * Just do not think the "/dev/mtdrX" devices support is need,
1120		 * so do not support them to avoid doing extra work.
1121		 */
1122		return ERR_PTR(-EINVAL);
1123
1124	return get_mtd_device(NULL, minor / 2);
1125}
1126
1127/**
1128 * open_mtd_device - open MTD device by name, character device path, or number.
1129 * @mtd_dev: name, character device node path, or MTD device device number
1130 *
1131 * This function tries to open and MTD device described by @mtd_dev string,
1132 * which is first treated as ASCII MTD device number, and if it is not true, it
1133 * is treated as MTD device name, and if that is also not true, it is treated
1134 * as MTD character device node path. Returns MTD device description object in
1135 * case of success and a negative error code in case of failure.
1136 */
1137static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
1138{
1139	struct mtd_info *mtd;
1140	int mtd_num;
1141	char *endp;
1142
1143	mtd_num = simple_strtoul(mtd_dev, &endp, 0);
1144	if (*endp != '\0' || mtd_dev == endp) {
1145		/*
1146		 * This does not look like an ASCII integer, probably this is
1147		 * MTD device name.
1148		 */
1149		mtd = get_mtd_device_nm(mtd_dev);
1150		if (IS_ERR(mtd) && PTR_ERR(mtd) == -ENODEV)
1151			/* Probably this is an MTD character device node path */
1152			mtd = open_mtd_by_chdev(mtd_dev);
1153	} else
1154		mtd = get_mtd_device(NULL, mtd_num);
1155
1156	return mtd;
1157}
1158
1159static int __init ubi_init(void)
1160{
1161	int err, i, k;
1162
1163	/* Ensure that EC and VID headers have correct size */
1164	BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
1165	BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);
1166
1167	if (mtd_devs > UBI_MAX_DEVICES) {
1168		ubi_err("too many MTD devices, maximum is %d", UBI_MAX_DEVICES);
1169		return -EINVAL;
1170	}
1171
1172	/* Create base sysfs directory and sysfs files */
1173	ubi_class = class_create(THIS_MODULE, UBI_NAME_STR);
1174	if (IS_ERR(ubi_class)) {
1175		err = PTR_ERR(ubi_class);
1176		ubi_err("cannot create UBI class");
1177		goto out;
1178	}
1179
1180	err = class_create_file(ubi_class, &ubi_version);
1181	if (err) {
1182		ubi_err("cannot create sysfs file");
1183		goto out_class;
1184	}
1185
1186	err = misc_register(&ubi_ctrl_cdev);
1187	if (err) {
1188		ubi_err("cannot register device");
1189		goto out_version;
1190	}
1191
1192	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
1193					      sizeof(struct ubi_wl_entry),
1194					      0, 0, NULL);
1195	if (!ubi_wl_entry_slab)
1196		goto out_dev_unreg;
1197
1198	/* Attach MTD devices */
1199	for (i = 0; i < mtd_devs; i++) {
1200		struct mtd_dev_param *p = &mtd_dev_param[i];
1201		struct mtd_info *mtd;
1202
1203		cond_resched();
1204
1205		mtd = open_mtd_device(p->name);
1206		if (IS_ERR(mtd)) {
1207			err = PTR_ERR(mtd);
1208			goto out_detach;
1209		}
1210
1211		mutex_lock(&ubi_devices_mutex);
1212		err = ubi_attach_mtd_dev(mtd, UBI_DEV_NUM_AUTO,
1213					 p->vid_hdr_offs);
1214		mutex_unlock(&ubi_devices_mutex);
1215		if (err < 0) {
1216			ubi_err("cannot attach mtd%d", mtd->index);
1217			put_mtd_device(mtd);
1218
1219			/*
1220			 * Originally UBI stopped initializing on any error.
1221			 * However, later on it was found out that this
1222			 * behavior is not very good when UBI is compiled into
1223			 * the kernel and the MTD devices to attach are passed
1224			 * through the command line. Indeed, UBI failure
1225			 * stopped whole boot sequence.
1226			 *
1227			 * To fix this, we changed the behavior for the
1228			 * non-module case, but preserved the old behavior for
1229			 * the module case, just for compatibility. This is a
1230			 * little inconsistent, though.
1231			 */
1232			if (ubi_is_module())
1233				goto out_detach;
1234		}
1235	}
1236
1237	return 0;
1238
1239out_detach:
1240	for (k = 0; k < i; k++)
1241		if (ubi_devices[k]) {
1242			mutex_lock(&ubi_devices_mutex);
1243			ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
1244			mutex_unlock(&ubi_devices_mutex);
1245		}
1246	kmem_cache_destroy(ubi_wl_entry_slab);
1247out_dev_unreg:
1248	misc_deregister(&ubi_ctrl_cdev);
1249out_version:
1250	class_remove_file(ubi_class, &ubi_version);
1251out_class:
1252	class_destroy(ubi_class);
1253out:
1254	ubi_err("UBI error: cannot initialize UBI, error %d", err);
1255	return err;
1256}
1257module_init(ubi_init);
1258
1259static void __exit ubi_exit(void)
1260{
1261	int i;
1262
1263	for (i = 0; i < UBI_MAX_DEVICES; i++)
1264		if (ubi_devices[i]) {
1265			mutex_lock(&ubi_devices_mutex);
1266			ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
1267			mutex_unlock(&ubi_devices_mutex);
1268		}
1269	kmem_cache_destroy(ubi_wl_entry_slab);
1270	misc_deregister(&ubi_ctrl_cdev);
1271	class_remove_file(ubi_class, &ubi_version);
1272	class_destroy(ubi_class);
1273}
1274module_exit(ubi_exit);
1275
1276/**
1277 * bytes_str_to_int - convert a number of bytes string into an integer.
1278 * @str: the string to convert
1279 *
1280 * This function returns positive resulting integer in case of success and a
1281 * negative error code in case of failure.
1282 */
1283static int __init bytes_str_to_int(const char *str)
1284{
1285	char *endp;
1286	unsigned long result;
1287
1288	result = simple_strtoul(str, &endp, 0);
1289	if (str == endp || result >= INT_MAX) {
1290		printk(KERN_ERR "UBI error: incorrect bytes count: \"%s\"\n",
1291		       str);
1292		return -EINVAL;
1293	}
1294
1295	switch (*endp) {
1296	case 'G':
1297		result *= 1024;
1298	case 'M':
1299		result *= 1024;
1300	case 'K':
1301		result *= 1024;
1302		if (endp[1] == 'i' && endp[2] == 'B')
1303			endp += 2;
1304	case '\0':
1305		break;
1306	default:
1307		printk(KERN_ERR "UBI error: incorrect bytes count: \"%s\"\n",
1308		       str);
1309		return -EINVAL;
1310	}
1311
1312	return result;
1313}
1314
1315/**
1316 * ubi_mtd_param_parse - parse the 'mtd=' UBI parameter.
1317 * @val: the parameter value to parse
1318 * @kp: not used
1319 *
1320 * This function returns zero in case of success and a negative error code in
1321 * case of error.
1322 */
1323static int __init ubi_mtd_param_parse(const char *val, struct kernel_param *kp)
1324{
1325	int i, len;
1326	struct mtd_dev_param *p;
1327	char buf[MTD_PARAM_LEN_MAX];
1328	char *pbuf = &buf[0];
1329	char *tokens[2] = {NULL, NULL};
1330
1331	if (!val)
1332		return -EINVAL;
1333
1334	if (mtd_devs == UBI_MAX_DEVICES) {
1335		printk(KERN_ERR "UBI error: too many parameters, max. is %d\n",
1336		       UBI_MAX_DEVICES);
1337		return -EINVAL;
1338	}
1339
1340	len = strnlen(val, MTD_PARAM_LEN_MAX);
1341	if (len == MTD_PARAM_LEN_MAX) {
1342		printk(KERN_ERR "UBI error: parameter \"%s\" is too long, "
1343		       "max. is %d\n", val, MTD_PARAM_LEN_MAX);
1344		return -EINVAL;
1345	}
1346
1347	if (len == 0) {
1348		printk(KERN_WARNING "UBI warning: empty 'mtd=' parameter - "
1349		       "ignored\n");
1350		return 0;
1351	}
1352
1353	strcpy(buf, val);
1354
1355	/* Get rid of the final newline */
1356	if (buf[len - 1] == '\n')
1357		buf[len - 1] = '\0';
1358
1359	for (i = 0; i < 2; i++)
1360		tokens[i] = strsep(&pbuf, ",");
1361
1362	if (pbuf) {
1363		printk(KERN_ERR "UBI error: too many arguments at \"%s\"\n",
1364		       val);
1365		return -EINVAL;
1366	}
1367
1368	p = &mtd_dev_param[mtd_devs];
1369	strcpy(&p->name[0], tokens[0]);
1370
1371	if (tokens[1])
1372		p->vid_hdr_offs = bytes_str_to_int(tokens[1]);
1373
1374	if (p->vid_hdr_offs < 0)
1375		return p->vid_hdr_offs;
1376
1377	mtd_devs += 1;
1378	return 0;
1379}
1380
1381module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 000);
1382MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: "
1383		      "mtd=<name|num|path>[,<vid_hdr_offs>].\n"
1384		      "Multiple \"mtd\" parameters may be specified.\n"
1385		      "MTD devices may be specified by their number, name, or "
1386		      "path to the MTD character device node.\n"
1387		      "Optional \"vid_hdr_offs\" parameter specifies UBI VID "
1388		      "header position to be used by UBI.\n"
1389		      "Example 1: mtd=/dev/mtd0 - attach MTD device "
1390		      "/dev/mtd0.\n"
1391		      "Example 2: mtd=content,1984 mtd=4 - attach MTD device "
1392		      "with name \"content\" using VID header offset 1984, and "
1393		      "MTD device number 4 with default VID header offset.");
1394
1395MODULE_VERSION(__stringify(UBI_VERSION));
1396MODULE_DESCRIPTION("UBI - Unsorted Block Images");
1397MODULE_AUTHOR("Artem Bityutskiy");
1398MODULE_LICENSE("GPL");
1399