xref: /openbmc/linux/drivers/mtd/ubi/build.c (revision 2c684d89)
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 (Битюцкий Артём),
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 
32 #include <linux/err.h>
33 #include <linux/module.h>
34 #include <linux/moduleparam.h>
35 #include <linux/stringify.h>
36 #include <linux/namei.h>
37 #include <linux/stat.h>
38 #include <linux/miscdevice.h>
39 #include <linux/mtd/partitions.h>
40 #include <linux/log2.h>
41 #include <linux/kthread.h>
42 #include <linux/kernel.h>
43 #include <linux/slab.h>
44 #include <linux/major.h>
45 #include "ubi.h"
46 
47 /* Maximum length of the 'mtd=' parameter */
48 #define MTD_PARAM_LEN_MAX 64
49 
50 /* Maximum number of comma-separated items in the 'mtd=' parameter */
51 #define MTD_PARAM_MAX_COUNT 4
52 
53 /* Maximum value for the number of bad PEBs per 1024 PEBs */
54 #define MAX_MTD_UBI_BEB_LIMIT 768
55 
56 #ifdef CONFIG_MTD_UBI_MODULE
57 #define ubi_is_module() 1
58 #else
59 #define ubi_is_module() 0
60 #endif
61 
62 /**
63  * struct mtd_dev_param - MTD device parameter description data structure.
64  * @name: MTD character device node path, MTD device name, or MTD device number
65  *        string
66  * @vid_hdr_offs: VID header offset
67  * @max_beb_per1024: maximum expected number of bad PEBs per 1024 PEBs
68  */
69 struct mtd_dev_param {
70 	char name[MTD_PARAM_LEN_MAX];
71 	int ubi_num;
72 	int vid_hdr_offs;
73 	int max_beb_per1024;
74 };
75 
76 /* Numbers of elements set in the @mtd_dev_param array */
77 static int __initdata mtd_devs;
78 
79 /* MTD devices specification parameters */
80 static struct mtd_dev_param __initdata mtd_dev_param[UBI_MAX_DEVICES];
81 #ifdef CONFIG_MTD_UBI_FASTMAP
82 /* UBI module parameter to enable fastmap automatically on non-fastmap images */
83 static bool fm_autoconvert;
84 static bool fm_debug;
85 #endif
86 
87 /* Slab cache for wear-leveling entries */
88 struct kmem_cache *ubi_wl_entry_slab;
89 
90 /* UBI control character device */
91 static struct miscdevice ubi_ctrl_cdev = {
92 	.minor = MISC_DYNAMIC_MINOR,
93 	.name = "ubi_ctrl",
94 	.fops = &ubi_ctrl_cdev_operations,
95 };
96 
97 /* All UBI devices in system */
98 static struct ubi_device *ubi_devices[UBI_MAX_DEVICES];
99 
100 /* Serializes UBI devices creations and removals */
101 DEFINE_MUTEX(ubi_devices_mutex);
102 
103 /* Protects @ubi_devices and @ubi->ref_count */
104 static DEFINE_SPINLOCK(ubi_devices_lock);
105 
106 /* "Show" method for files in '/<sysfs>/class/ubi/' */
107 static ssize_t ubi_version_show(struct class *class,
108 				struct class_attribute *attr, char *buf)
109 {
110 	return sprintf(buf, "%d\n", UBI_VERSION);
111 }
112 
113 /* UBI version attribute ('/<sysfs>/class/ubi/version') */
114 static struct class_attribute ubi_class_attrs[] = {
115 	__ATTR(version, S_IRUGO, ubi_version_show, NULL),
116 	__ATTR_NULL
117 };
118 
119 /* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
120 struct class ubi_class = {
121 	.name		= UBI_NAME_STR,
122 	.owner		= THIS_MODULE,
123 	.class_attrs	= ubi_class_attrs,
124 };
125 
126 static ssize_t dev_attribute_show(struct device *dev,
127 				  struct device_attribute *attr, char *buf);
128 
129 /* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
130 static struct device_attribute dev_eraseblock_size =
131 	__ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
132 static struct device_attribute dev_avail_eraseblocks =
133 	__ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
134 static struct device_attribute dev_total_eraseblocks =
135 	__ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
136 static struct device_attribute dev_volumes_count =
137 	__ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
138 static struct device_attribute dev_max_ec =
139 	__ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
140 static struct device_attribute dev_reserved_for_bad =
141 	__ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
142 static struct device_attribute dev_bad_peb_count =
143 	__ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
144 static struct device_attribute dev_max_vol_count =
145 	__ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
146 static struct device_attribute dev_min_io_size =
147 	__ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
148 static struct device_attribute dev_bgt_enabled =
149 	__ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);
150 static struct device_attribute dev_mtd_num =
151 	__ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
152 
153 /**
154  * ubi_volume_notify - send a volume change notification.
155  * @ubi: UBI device description object
156  * @vol: volume description object of the changed volume
157  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
158  *
159  * This is a helper function which notifies all subscribers about a volume
160  * change event (creation, removal, re-sizing, re-naming, updating). Returns
161  * zero in case of success and a negative error code in case of failure.
162  */
163 int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
164 {
165 	int ret;
166 	struct ubi_notification nt;
167 
168 	ubi_do_get_device_info(ubi, &nt.di);
169 	ubi_do_get_volume_info(ubi, vol, &nt.vi);
170 
171 	switch (ntype) {
172 	case UBI_VOLUME_ADDED:
173 	case UBI_VOLUME_REMOVED:
174 	case UBI_VOLUME_RESIZED:
175 	case UBI_VOLUME_RENAMED:
176 		ret = ubi_update_fastmap(ubi);
177 		if (ret)
178 			ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
179 	}
180 
181 	return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
182 }
183 
184 /**
185  * ubi_notify_all - send a notification to all volumes.
186  * @ubi: UBI device description object
187  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
188  * @nb: the notifier to call
189  *
190  * This function walks all volumes of UBI device @ubi and sends the @ntype
191  * notification for each volume. If @nb is %NULL, then all registered notifiers
192  * are called, otherwise only the @nb notifier is called. Returns the number of
193  * sent notifications.
194  */
195 int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
196 {
197 	struct ubi_notification nt;
198 	int i, count = 0;
199 
200 	ubi_do_get_device_info(ubi, &nt.di);
201 
202 	mutex_lock(&ubi->device_mutex);
203 	for (i = 0; i < ubi->vtbl_slots; i++) {
204 		/*
205 		 * Since the @ubi->device is locked, and we are not going to
206 		 * change @ubi->volumes, we do not have to lock
207 		 * @ubi->volumes_lock.
208 		 */
209 		if (!ubi->volumes[i])
210 			continue;
211 
212 		ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
213 		if (nb)
214 			nb->notifier_call(nb, ntype, &nt);
215 		else
216 			blocking_notifier_call_chain(&ubi_notifiers, ntype,
217 						     &nt);
218 		count += 1;
219 	}
220 	mutex_unlock(&ubi->device_mutex);
221 
222 	return count;
223 }
224 
225 /**
226  * ubi_enumerate_volumes - send "add" notification for all existing volumes.
227  * @nb: the notifier to call
228  *
229  * This function walks all UBI devices and volumes and sends the
230  * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
231  * registered notifiers are called, otherwise only the @nb notifier is called.
232  * Returns the number of sent notifications.
233  */
234 int ubi_enumerate_volumes(struct notifier_block *nb)
235 {
236 	int i, count = 0;
237 
238 	/*
239 	 * Since the @ubi_devices_mutex is locked, and we are not going to
240 	 * change @ubi_devices, we do not have to lock @ubi_devices_lock.
241 	 */
242 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
243 		struct ubi_device *ubi = ubi_devices[i];
244 
245 		if (!ubi)
246 			continue;
247 		count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
248 	}
249 
250 	return count;
251 }
252 
253 /**
254  * ubi_get_device - get UBI device.
255  * @ubi_num: UBI device number
256  *
257  * This function returns UBI device description object for UBI device number
258  * @ubi_num, or %NULL if the device does not exist. This function increases the
259  * device reference count to prevent removal of the device. In other words, the
260  * device cannot be removed if its reference count is not zero.
261  */
262 struct ubi_device *ubi_get_device(int ubi_num)
263 {
264 	struct ubi_device *ubi;
265 
266 	spin_lock(&ubi_devices_lock);
267 	ubi = ubi_devices[ubi_num];
268 	if (ubi) {
269 		ubi_assert(ubi->ref_count >= 0);
270 		ubi->ref_count += 1;
271 		get_device(&ubi->dev);
272 	}
273 	spin_unlock(&ubi_devices_lock);
274 
275 	return ubi;
276 }
277 
278 /**
279  * ubi_put_device - drop an UBI device reference.
280  * @ubi: UBI device description object
281  */
282 void ubi_put_device(struct ubi_device *ubi)
283 {
284 	spin_lock(&ubi_devices_lock);
285 	ubi->ref_count -= 1;
286 	put_device(&ubi->dev);
287 	spin_unlock(&ubi_devices_lock);
288 }
289 
290 /**
291  * ubi_get_by_major - get UBI device by character device major number.
292  * @major: major number
293  *
294  * This function is similar to 'ubi_get_device()', but it searches the device
295  * by its major number.
296  */
297 struct ubi_device *ubi_get_by_major(int major)
298 {
299 	int i;
300 	struct ubi_device *ubi;
301 
302 	spin_lock(&ubi_devices_lock);
303 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
304 		ubi = ubi_devices[i];
305 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
306 			ubi_assert(ubi->ref_count >= 0);
307 			ubi->ref_count += 1;
308 			get_device(&ubi->dev);
309 			spin_unlock(&ubi_devices_lock);
310 			return ubi;
311 		}
312 	}
313 	spin_unlock(&ubi_devices_lock);
314 
315 	return NULL;
316 }
317 
318 /**
319  * ubi_major2num - get UBI device number by character device major number.
320  * @major: major number
321  *
322  * This function searches UBI device number object by its major number. If UBI
323  * device was not found, this function returns -ENODEV, otherwise the UBI device
324  * number is returned.
325  */
326 int ubi_major2num(int major)
327 {
328 	int i, ubi_num = -ENODEV;
329 
330 	spin_lock(&ubi_devices_lock);
331 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
332 		struct ubi_device *ubi = ubi_devices[i];
333 
334 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
335 			ubi_num = ubi->ubi_num;
336 			break;
337 		}
338 	}
339 	spin_unlock(&ubi_devices_lock);
340 
341 	return ubi_num;
342 }
343 
344 /* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
345 static ssize_t dev_attribute_show(struct device *dev,
346 				  struct device_attribute *attr, char *buf)
347 {
348 	ssize_t ret;
349 	struct ubi_device *ubi;
350 
351 	/*
352 	 * The below code looks weird, but it actually makes sense. We get the
353 	 * UBI device reference from the contained 'struct ubi_device'. But it
354 	 * is unclear if the device was removed or not yet. Indeed, if the
355 	 * device was removed before we increased its reference count,
356 	 * 'ubi_get_device()' will return -ENODEV and we fail.
357 	 *
358 	 * Remember, 'struct ubi_device' is freed in the release function, so
359 	 * we still can use 'ubi->ubi_num'.
360 	 */
361 	ubi = container_of(dev, struct ubi_device, dev);
362 	ubi = ubi_get_device(ubi->ubi_num);
363 	if (!ubi)
364 		return -ENODEV;
365 
366 	if (attr == &dev_eraseblock_size)
367 		ret = sprintf(buf, "%d\n", ubi->leb_size);
368 	else if (attr == &dev_avail_eraseblocks)
369 		ret = sprintf(buf, "%d\n", ubi->avail_pebs);
370 	else if (attr == &dev_total_eraseblocks)
371 		ret = sprintf(buf, "%d\n", ubi->good_peb_count);
372 	else if (attr == &dev_volumes_count)
373 		ret = sprintf(buf, "%d\n", ubi->vol_count - UBI_INT_VOL_COUNT);
374 	else if (attr == &dev_max_ec)
375 		ret = sprintf(buf, "%d\n", ubi->max_ec);
376 	else if (attr == &dev_reserved_for_bad)
377 		ret = sprintf(buf, "%d\n", ubi->beb_rsvd_pebs);
378 	else if (attr == &dev_bad_peb_count)
379 		ret = sprintf(buf, "%d\n", ubi->bad_peb_count);
380 	else if (attr == &dev_max_vol_count)
381 		ret = sprintf(buf, "%d\n", ubi->vtbl_slots);
382 	else if (attr == &dev_min_io_size)
383 		ret = sprintf(buf, "%d\n", ubi->min_io_size);
384 	else if (attr == &dev_bgt_enabled)
385 		ret = sprintf(buf, "%d\n", ubi->thread_enabled);
386 	else if (attr == &dev_mtd_num)
387 		ret = sprintf(buf, "%d\n", ubi->mtd->index);
388 	else
389 		ret = -EINVAL;
390 
391 	ubi_put_device(ubi);
392 	return ret;
393 }
394 
395 static struct attribute *ubi_dev_attrs[] = {
396 	&dev_eraseblock_size.attr,
397 	&dev_avail_eraseblocks.attr,
398 	&dev_total_eraseblocks.attr,
399 	&dev_volumes_count.attr,
400 	&dev_max_ec.attr,
401 	&dev_reserved_for_bad.attr,
402 	&dev_bad_peb_count.attr,
403 	&dev_max_vol_count.attr,
404 	&dev_min_io_size.attr,
405 	&dev_bgt_enabled.attr,
406 	&dev_mtd_num.attr,
407 	NULL
408 };
409 ATTRIBUTE_GROUPS(ubi_dev);
410 
411 static void dev_release(struct device *dev)
412 {
413 	struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);
414 
415 	kfree(ubi);
416 }
417 
418 /**
419  * ubi_sysfs_init - initialize sysfs for an UBI device.
420  * @ubi: UBI device description object
421  * @ref: set to %1 on exit in case of failure if a reference to @ubi->dev was
422  *       taken
423  *
424  * This function returns zero in case of success and a negative error code in
425  * case of failure.
426  */
427 static int ubi_sysfs_init(struct ubi_device *ubi, int *ref)
428 {
429 	int err;
430 
431 	ubi->dev.release = dev_release;
432 	ubi->dev.devt = ubi->cdev.dev;
433 	ubi->dev.class = &ubi_class;
434 	ubi->dev.groups = ubi_dev_groups;
435 	dev_set_name(&ubi->dev, UBI_NAME_STR"%d", ubi->ubi_num);
436 	err = device_register(&ubi->dev);
437 	if (err)
438 		return err;
439 
440 	*ref = 1;
441 	return 0;
442 }
443 
444 /**
445  * ubi_sysfs_close - close sysfs for an UBI device.
446  * @ubi: UBI device description object
447  */
448 static void ubi_sysfs_close(struct ubi_device *ubi)
449 {
450 	device_unregister(&ubi->dev);
451 }
452 
453 /**
454  * kill_volumes - destroy all user volumes.
455  * @ubi: UBI device description object
456  */
457 static void kill_volumes(struct ubi_device *ubi)
458 {
459 	int i;
460 
461 	for (i = 0; i < ubi->vtbl_slots; i++)
462 		if (ubi->volumes[i])
463 			ubi_free_volume(ubi, ubi->volumes[i]);
464 }
465 
466 /**
467  * uif_init - initialize user interfaces for an UBI device.
468  * @ubi: UBI device description object
469  * @ref: set to %1 on exit in case of failure if a reference to @ubi->dev was
470  *       taken, otherwise set to %0
471  *
472  * This function initializes various user interfaces for an UBI device. If the
473  * initialization fails at an early stage, this function frees all the
474  * resources it allocated, returns an error, and @ref is set to %0. However,
475  * if the initialization fails after the UBI device was registered in the
476  * driver core subsystem, this function takes a reference to @ubi->dev, because
477  * otherwise the release function ('dev_release()') would free whole @ubi
478  * object. The @ref argument is set to %1 in this case. The caller has to put
479  * this reference.
480  *
481  * This function returns zero in case of success and a negative error code in
482  * case of failure.
483  */
484 static int uif_init(struct ubi_device *ubi, int *ref)
485 {
486 	int i, err;
487 	dev_t dev;
488 
489 	*ref = 0;
490 	sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);
491 
492 	/*
493 	 * Major numbers for the UBI character devices are allocated
494 	 * dynamically. Major numbers of volume character devices are
495 	 * equivalent to ones of the corresponding UBI character device. Minor
496 	 * numbers of UBI character devices are 0, while minor numbers of
497 	 * volume character devices start from 1. Thus, we allocate one major
498 	 * number and ubi->vtbl_slots + 1 minor numbers.
499 	 */
500 	err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
501 	if (err) {
502 		ubi_err(ubi, "cannot register UBI character devices");
503 		return err;
504 	}
505 
506 	ubi_assert(MINOR(dev) == 0);
507 	cdev_init(&ubi->cdev, &ubi_cdev_operations);
508 	dbg_gen("%s major is %u", ubi->ubi_name, MAJOR(dev));
509 	ubi->cdev.owner = THIS_MODULE;
510 
511 	err = cdev_add(&ubi->cdev, dev, 1);
512 	if (err) {
513 		ubi_err(ubi, "cannot add character device");
514 		goto out_unreg;
515 	}
516 
517 	err = ubi_sysfs_init(ubi, ref);
518 	if (err)
519 		goto out_sysfs;
520 
521 	for (i = 0; i < ubi->vtbl_slots; i++)
522 		if (ubi->volumes[i]) {
523 			err = ubi_add_volume(ubi, ubi->volumes[i]);
524 			if (err) {
525 				ubi_err(ubi, "cannot add volume %d", i);
526 				goto out_volumes;
527 			}
528 		}
529 
530 	return 0;
531 
532 out_volumes:
533 	kill_volumes(ubi);
534 out_sysfs:
535 	if (*ref)
536 		get_device(&ubi->dev);
537 	ubi_sysfs_close(ubi);
538 	cdev_del(&ubi->cdev);
539 out_unreg:
540 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
541 	ubi_err(ubi, "cannot initialize UBI %s, error %d",
542 		ubi->ubi_name, err);
543 	return err;
544 }
545 
546 /**
547  * uif_close - close user interfaces for an UBI device.
548  * @ubi: UBI device description object
549  *
550  * Note, since this function un-registers UBI volume device objects (@vol->dev),
551  * the memory allocated voe the volumes is freed as well (in the release
552  * function).
553  */
554 static void uif_close(struct ubi_device *ubi)
555 {
556 	kill_volumes(ubi);
557 	ubi_sysfs_close(ubi);
558 	cdev_del(&ubi->cdev);
559 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
560 }
561 
562 /**
563  * ubi_free_internal_volumes - free internal volumes.
564  * @ubi: UBI device description object
565  */
566 void ubi_free_internal_volumes(struct ubi_device *ubi)
567 {
568 	int i;
569 
570 	for (i = ubi->vtbl_slots;
571 	     i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
572 		kfree(ubi->volumes[i]->eba_tbl);
573 		kfree(ubi->volumes[i]);
574 	}
575 }
576 
577 static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
578 {
579 	int limit, device_pebs;
580 	uint64_t device_size;
581 
582 	if (!max_beb_per1024)
583 		return 0;
584 
585 	/*
586 	 * Here we are using size of the entire flash chip and
587 	 * not just the MTD partition size because the maximum
588 	 * number of bad eraseblocks is a percentage of the
589 	 * whole device and bad eraseblocks are not fairly
590 	 * distributed over the flash chip. So the worst case
591 	 * is that all the bad eraseblocks of the chip are in
592 	 * the MTD partition we are attaching (ubi->mtd).
593 	 */
594 	device_size = mtd_get_device_size(ubi->mtd);
595 	device_pebs = mtd_div_by_eb(device_size, ubi->mtd);
596 	limit = mult_frac(device_pebs, max_beb_per1024, 1024);
597 
598 	/* Round it up */
599 	if (mult_frac(limit, 1024, max_beb_per1024) < device_pebs)
600 		limit += 1;
601 
602 	return limit;
603 }
604 
605 /**
606  * io_init - initialize I/O sub-system for a given UBI device.
607  * @ubi: UBI device description object
608  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
609  *
610  * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
611  * assumed:
612  *   o EC header is always at offset zero - this cannot be changed;
613  *   o VID header starts just after the EC header at the closest address
614  *     aligned to @io->hdrs_min_io_size;
615  *   o data starts just after the VID header at the closest address aligned to
616  *     @io->min_io_size
617  *
618  * This function returns zero in case of success and a negative error code in
619  * case of failure.
620  */
621 static int io_init(struct ubi_device *ubi, int max_beb_per1024)
622 {
623 	dbg_gen("sizeof(struct ubi_ainf_peb) %zu", sizeof(struct ubi_ainf_peb));
624 	dbg_gen("sizeof(struct ubi_wl_entry) %zu", sizeof(struct ubi_wl_entry));
625 
626 	if (ubi->mtd->numeraseregions != 0) {
627 		/*
628 		 * Some flashes have several erase regions. Different regions
629 		 * may have different eraseblock size and other
630 		 * characteristics. It looks like mostly multi-region flashes
631 		 * have one "main" region and one or more small regions to
632 		 * store boot loader code or boot parameters or whatever. I
633 		 * guess we should just pick the largest region. But this is
634 		 * not implemented.
635 		 */
636 		ubi_err(ubi, "multiple regions, not implemented");
637 		return -EINVAL;
638 	}
639 
640 	if (ubi->vid_hdr_offset < 0)
641 		return -EINVAL;
642 
643 	/*
644 	 * Note, in this implementation we support MTD devices with 0x7FFFFFFF
645 	 * physical eraseblocks maximum.
646 	 */
647 
648 	ubi->peb_size   = ubi->mtd->erasesize;
649 	ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
650 	ubi->flash_size = ubi->mtd->size;
651 
652 	if (mtd_can_have_bb(ubi->mtd)) {
653 		ubi->bad_allowed = 1;
654 		ubi->bad_peb_limit = get_bad_peb_limit(ubi, max_beb_per1024);
655 	}
656 
657 	if (ubi->mtd->type == MTD_NORFLASH) {
658 		ubi_assert(ubi->mtd->writesize == 1);
659 		ubi->nor_flash = 1;
660 	}
661 
662 	ubi->min_io_size = ubi->mtd->writesize;
663 	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
664 
665 	/*
666 	 * Make sure minimal I/O unit is power of 2. Note, there is no
667 	 * fundamental reason for this assumption. It is just an optimization
668 	 * which allows us to avoid costly division operations.
669 	 */
670 	if (!is_power_of_2(ubi->min_io_size)) {
671 		ubi_err(ubi, "min. I/O unit (%d) is not power of 2",
672 			ubi->min_io_size);
673 		return -EINVAL;
674 	}
675 
676 	ubi_assert(ubi->hdrs_min_io_size > 0);
677 	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
678 	ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
679 
680 	ubi->max_write_size = ubi->mtd->writebufsize;
681 	/*
682 	 * Maximum write size has to be greater or equivalent to min. I/O
683 	 * size, and be multiple of min. I/O size.
684 	 */
685 	if (ubi->max_write_size < ubi->min_io_size ||
686 	    ubi->max_write_size % ubi->min_io_size ||
687 	    !is_power_of_2(ubi->max_write_size)) {
688 		ubi_err(ubi, "bad write buffer size %d for %d min. I/O unit",
689 			ubi->max_write_size, ubi->min_io_size);
690 		return -EINVAL;
691 	}
692 
693 	/* Calculate default aligned sizes of EC and VID headers */
694 	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
695 	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
696 
697 	dbg_gen("min_io_size      %d", ubi->min_io_size);
698 	dbg_gen("max_write_size   %d", ubi->max_write_size);
699 	dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
700 	dbg_gen("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
701 	dbg_gen("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
702 
703 	if (ubi->vid_hdr_offset == 0)
704 		/* Default offset */
705 		ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
706 				      ubi->ec_hdr_alsize;
707 	else {
708 		ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
709 						~(ubi->hdrs_min_io_size - 1);
710 		ubi->vid_hdr_shift = ubi->vid_hdr_offset -
711 						ubi->vid_hdr_aloffset;
712 	}
713 
714 	/* Similar for the data offset */
715 	ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
716 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
717 
718 	dbg_gen("vid_hdr_offset   %d", ubi->vid_hdr_offset);
719 	dbg_gen("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
720 	dbg_gen("vid_hdr_shift    %d", ubi->vid_hdr_shift);
721 	dbg_gen("leb_start        %d", ubi->leb_start);
722 
723 	/* The shift must be aligned to 32-bit boundary */
724 	if (ubi->vid_hdr_shift % 4) {
725 		ubi_err(ubi, "unaligned VID header shift %d",
726 			ubi->vid_hdr_shift);
727 		return -EINVAL;
728 	}
729 
730 	/* Check sanity */
731 	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
732 	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
733 	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
734 	    ubi->leb_start & (ubi->min_io_size - 1)) {
735 		ubi_err(ubi, "bad VID header (%d) or data offsets (%d)",
736 			ubi->vid_hdr_offset, ubi->leb_start);
737 		return -EINVAL;
738 	}
739 
740 	/*
741 	 * Set maximum amount of physical erroneous eraseblocks to be 10%.
742 	 * Erroneous PEB are those which have read errors.
743 	 */
744 	ubi->max_erroneous = ubi->peb_count / 10;
745 	if (ubi->max_erroneous < 16)
746 		ubi->max_erroneous = 16;
747 	dbg_gen("max_erroneous    %d", ubi->max_erroneous);
748 
749 	/*
750 	 * It may happen that EC and VID headers are situated in one minimal
751 	 * I/O unit. In this case we can only accept this UBI image in
752 	 * read-only mode.
753 	 */
754 	if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
755 		ubi_warn(ubi, "EC and VID headers are in the same minimal I/O unit, switch to read-only mode");
756 		ubi->ro_mode = 1;
757 	}
758 
759 	ubi->leb_size = ubi->peb_size - ubi->leb_start;
760 
761 	if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
762 		ubi_msg(ubi, "MTD device %d is write-protected, attach in read-only mode",
763 			ubi->mtd->index);
764 		ubi->ro_mode = 1;
765 	}
766 
767 	/*
768 	 * Note, ideally, we have to initialize @ubi->bad_peb_count here. But
769 	 * unfortunately, MTD does not provide this information. We should loop
770 	 * over all physical eraseblocks and invoke mtd->block_is_bad() for
771 	 * each physical eraseblock. So, we leave @ubi->bad_peb_count
772 	 * uninitialized so far.
773 	 */
774 
775 	return 0;
776 }
777 
778 /**
779  * autoresize - re-size the volume which has the "auto-resize" flag set.
780  * @ubi: UBI device description object
781  * @vol_id: ID of the volume to re-size
782  *
783  * This function re-sizes the volume marked by the %UBI_VTBL_AUTORESIZE_FLG in
784  * the volume table to the largest possible size. See comments in ubi-header.h
785  * for more description of the flag. Returns zero in case of success and a
786  * negative error code in case of failure.
787  */
788 static int autoresize(struct ubi_device *ubi, int vol_id)
789 {
790 	struct ubi_volume_desc desc;
791 	struct ubi_volume *vol = ubi->volumes[vol_id];
792 	int err, old_reserved_pebs = vol->reserved_pebs;
793 
794 	if (ubi->ro_mode) {
795 		ubi_warn(ubi, "skip auto-resize because of R/O mode");
796 		return 0;
797 	}
798 
799 	/*
800 	 * Clear the auto-resize flag in the volume in-memory copy of the
801 	 * volume table, and 'ubi_resize_volume()' will propagate this change
802 	 * to the flash.
803 	 */
804 	ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;
805 
806 	if (ubi->avail_pebs == 0) {
807 		struct ubi_vtbl_record vtbl_rec;
808 
809 		/*
810 		 * No available PEBs to re-size the volume, clear the flag on
811 		 * flash and exit.
812 		 */
813 		vtbl_rec = ubi->vtbl[vol_id];
814 		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
815 		if (err)
816 			ubi_err(ubi, "cannot clean auto-resize flag for volume %d",
817 				vol_id);
818 	} else {
819 		desc.vol = vol;
820 		err = ubi_resize_volume(&desc,
821 					old_reserved_pebs + ubi->avail_pebs);
822 		if (err)
823 			ubi_err(ubi, "cannot auto-resize volume %d",
824 				vol_id);
825 	}
826 
827 	if (err)
828 		return err;
829 
830 	ubi_msg(ubi, "volume %d (\"%s\") re-sized from %d to %d LEBs",
831 		vol_id, vol->name, old_reserved_pebs, vol->reserved_pebs);
832 	return 0;
833 }
834 
835 /**
836  * ubi_attach_mtd_dev - attach an MTD device.
837  * @mtd: MTD device description object
838  * @ubi_num: number to assign to the new UBI device
839  * @vid_hdr_offset: VID header offset
840  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
841  *
842  * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
843  * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
844  * which case this function finds a vacant device number and assigns it
845  * automatically. Returns the new UBI device number in case of success and a
846  * negative error code in case of failure.
847  *
848  * Note, the invocations of this function has to be serialized by the
849  * @ubi_devices_mutex.
850  */
851 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
852 		       int vid_hdr_offset, int max_beb_per1024)
853 {
854 	struct ubi_device *ubi;
855 	int i, err, ref = 0;
856 
857 	if (max_beb_per1024 < 0 || max_beb_per1024 > MAX_MTD_UBI_BEB_LIMIT)
858 		return -EINVAL;
859 
860 	if (!max_beb_per1024)
861 		max_beb_per1024 = CONFIG_MTD_UBI_BEB_LIMIT;
862 
863 	/*
864 	 * Check if we already have the same MTD device attached.
865 	 *
866 	 * Note, this function assumes that UBI devices creations and deletions
867 	 * are serialized, so it does not take the &ubi_devices_lock.
868 	 */
869 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
870 		ubi = ubi_devices[i];
871 		if (ubi && mtd->index == ubi->mtd->index) {
872 			ubi_err(ubi, "mtd%d is already attached to ubi%d",
873 				mtd->index, i);
874 			return -EEXIST;
875 		}
876 	}
877 
878 	/*
879 	 * Make sure this MTD device is not emulated on top of an UBI volume
880 	 * already. Well, generally this recursion works fine, but there are
881 	 * different problems like the UBI module takes a reference to itself
882 	 * by attaching (and thus, opening) the emulated MTD device. This
883 	 * results in inability to unload the module. And in general it makes
884 	 * no sense to attach emulated MTD devices, so we prohibit this.
885 	 */
886 	if (mtd->type == MTD_UBIVOLUME) {
887 		ubi_err(ubi, "refuse attaching mtd%d - it is already emulated on top of UBI",
888 			mtd->index);
889 		return -EINVAL;
890 	}
891 
892 	if (ubi_num == UBI_DEV_NUM_AUTO) {
893 		/* Search for an empty slot in the @ubi_devices array */
894 		for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
895 			if (!ubi_devices[ubi_num])
896 				break;
897 		if (ubi_num == UBI_MAX_DEVICES) {
898 			ubi_err(ubi, "only %d UBI devices may be created",
899 				UBI_MAX_DEVICES);
900 			return -ENFILE;
901 		}
902 	} else {
903 		if (ubi_num >= UBI_MAX_DEVICES)
904 			return -EINVAL;
905 
906 		/* Make sure ubi_num is not busy */
907 		if (ubi_devices[ubi_num]) {
908 			ubi_err(ubi, "already exists");
909 			return -EEXIST;
910 		}
911 	}
912 
913 	ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
914 	if (!ubi)
915 		return -ENOMEM;
916 
917 	ubi->mtd = mtd;
918 	ubi->ubi_num = ubi_num;
919 	ubi->vid_hdr_offset = vid_hdr_offset;
920 	ubi->autoresize_vol_id = -1;
921 
922 #ifdef CONFIG_MTD_UBI_FASTMAP
923 	ubi->fm_pool.used = ubi->fm_pool.size = 0;
924 	ubi->fm_wl_pool.used = ubi->fm_wl_pool.size = 0;
925 
926 	/*
927 	 * fm_pool.max_size is 5% of the total number of PEBs but it's also
928 	 * between UBI_FM_MAX_POOL_SIZE and UBI_FM_MIN_POOL_SIZE.
929 	 */
930 	ubi->fm_pool.max_size = min(((int)mtd_div_by_eb(ubi->mtd->size,
931 		ubi->mtd) / 100) * 5, UBI_FM_MAX_POOL_SIZE);
932 	ubi->fm_pool.max_size = max(ubi->fm_pool.max_size,
933 		UBI_FM_MIN_POOL_SIZE);
934 
935 	ubi->fm_wl_pool.max_size = ubi->fm_pool.max_size / 2;
936 	ubi->fm_disabled = !fm_autoconvert;
937 	if (fm_debug)
938 		ubi_enable_dbg_chk_fastmap(ubi);
939 
940 	if (!ubi->fm_disabled && (int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd)
941 	    <= UBI_FM_MAX_START) {
942 		ubi_err(ubi, "More than %i PEBs are needed for fastmap, sorry.",
943 			UBI_FM_MAX_START);
944 		ubi->fm_disabled = 1;
945 	}
946 
947 	ubi_msg(ubi, "default fastmap pool size: %d", ubi->fm_pool.max_size);
948 	ubi_msg(ubi, "default fastmap WL pool size: %d",
949 		ubi->fm_wl_pool.max_size);
950 #else
951 	ubi->fm_disabled = 1;
952 #endif
953 	mutex_init(&ubi->buf_mutex);
954 	mutex_init(&ubi->ckvol_mutex);
955 	mutex_init(&ubi->device_mutex);
956 	spin_lock_init(&ubi->volumes_lock);
957 	init_rwsem(&ubi->fm_protect);
958 	init_rwsem(&ubi->fm_eba_sem);
959 
960 	ubi_msg(ubi, "attaching mtd%d", mtd->index);
961 
962 	err = io_init(ubi, max_beb_per1024);
963 	if (err)
964 		goto out_free;
965 
966 	err = -ENOMEM;
967 	ubi->peb_buf = vmalloc(ubi->peb_size);
968 	if (!ubi->peb_buf)
969 		goto out_free;
970 
971 #ifdef CONFIG_MTD_UBI_FASTMAP
972 	ubi->fm_size = ubi_calc_fm_size(ubi);
973 	ubi->fm_buf = vzalloc(ubi->fm_size);
974 	if (!ubi->fm_buf)
975 		goto out_free;
976 #endif
977 	err = ubi_attach(ubi, 0);
978 	if (err) {
979 		ubi_err(ubi, "failed to attach mtd%d, error %d",
980 			mtd->index, err);
981 		goto out_free;
982 	}
983 
984 	if (ubi->autoresize_vol_id != -1) {
985 		err = autoresize(ubi, ubi->autoresize_vol_id);
986 		if (err)
987 			goto out_detach;
988 	}
989 
990 	err = uif_init(ubi, &ref);
991 	if (err)
992 		goto out_detach;
993 
994 	err = ubi_debugfs_init_dev(ubi);
995 	if (err)
996 		goto out_uif;
997 
998 	ubi->bgt_thread = kthread_create(ubi_thread, ubi, "%s", ubi->bgt_name);
999 	if (IS_ERR(ubi->bgt_thread)) {
1000 		err = PTR_ERR(ubi->bgt_thread);
1001 		ubi_err(ubi, "cannot spawn \"%s\", error %d",
1002 			ubi->bgt_name, err);
1003 		goto out_debugfs;
1004 	}
1005 
1006 	ubi_msg(ubi, "attached mtd%d (name \"%s\", size %llu MiB)",
1007 		mtd->index, mtd->name, ubi->flash_size >> 20);
1008 	ubi_msg(ubi, "PEB size: %d bytes (%d KiB), LEB size: %d bytes",
1009 		ubi->peb_size, ubi->peb_size >> 10, ubi->leb_size);
1010 	ubi_msg(ubi, "min./max. I/O unit sizes: %d/%d, sub-page size %d",
1011 		ubi->min_io_size, ubi->max_write_size, ubi->hdrs_min_io_size);
1012 	ubi_msg(ubi, "VID header offset: %d (aligned %d), data offset: %d",
1013 		ubi->vid_hdr_offset, ubi->vid_hdr_aloffset, ubi->leb_start);
1014 	ubi_msg(ubi, "good PEBs: %d, bad PEBs: %d, corrupted PEBs: %d",
1015 		ubi->good_peb_count, ubi->bad_peb_count, ubi->corr_peb_count);
1016 	ubi_msg(ubi, "user volume: %d, internal volumes: %d, max. volumes count: %d",
1017 		ubi->vol_count - UBI_INT_VOL_COUNT, UBI_INT_VOL_COUNT,
1018 		ubi->vtbl_slots);
1019 	ubi_msg(ubi, "max/mean erase counter: %d/%d, WL threshold: %d, image sequence number: %u",
1020 		ubi->max_ec, ubi->mean_ec, CONFIG_MTD_UBI_WL_THRESHOLD,
1021 		ubi->image_seq);
1022 	ubi_msg(ubi, "available PEBs: %d, total reserved PEBs: %d, PEBs reserved for bad PEB handling: %d",
1023 		ubi->avail_pebs, ubi->rsvd_pebs, ubi->beb_rsvd_pebs);
1024 
1025 	/*
1026 	 * The below lock makes sure we do not race with 'ubi_thread()' which
1027 	 * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
1028 	 */
1029 	spin_lock(&ubi->wl_lock);
1030 	ubi->thread_enabled = 1;
1031 	wake_up_process(ubi->bgt_thread);
1032 	spin_unlock(&ubi->wl_lock);
1033 
1034 	ubi_devices[ubi_num] = ubi;
1035 	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
1036 	return ubi_num;
1037 
1038 out_debugfs:
1039 	ubi_debugfs_exit_dev(ubi);
1040 out_uif:
1041 	get_device(&ubi->dev);
1042 	ubi_assert(ref);
1043 	uif_close(ubi);
1044 out_detach:
1045 	ubi_wl_close(ubi);
1046 	ubi_free_internal_volumes(ubi);
1047 	vfree(ubi->vtbl);
1048 out_free:
1049 	vfree(ubi->peb_buf);
1050 	vfree(ubi->fm_buf);
1051 	if (ref)
1052 		put_device(&ubi->dev);
1053 	else
1054 		kfree(ubi);
1055 	return err;
1056 }
1057 
1058 /**
1059  * ubi_detach_mtd_dev - detach an MTD device.
1060  * @ubi_num: UBI device number to detach from
1061  * @anyway: detach MTD even if device reference count is not zero
1062  *
1063  * This function destroys an UBI device number @ubi_num and detaches the
1064  * underlying MTD device. Returns zero in case of success and %-EBUSY if the
1065  * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
1066  * exist.
1067  *
1068  * Note, the invocations of this function has to be serialized by the
1069  * @ubi_devices_mutex.
1070  */
1071 int ubi_detach_mtd_dev(int ubi_num, int anyway)
1072 {
1073 	struct ubi_device *ubi;
1074 
1075 	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
1076 		return -EINVAL;
1077 
1078 	ubi = ubi_get_device(ubi_num);
1079 	if (!ubi)
1080 		return -EINVAL;
1081 
1082 	spin_lock(&ubi_devices_lock);
1083 	put_device(&ubi->dev);
1084 	ubi->ref_count -= 1;
1085 	if (ubi->ref_count) {
1086 		if (!anyway) {
1087 			spin_unlock(&ubi_devices_lock);
1088 			return -EBUSY;
1089 		}
1090 		/* This may only happen if there is a bug */
1091 		ubi_err(ubi, "%s reference count %d, destroy anyway",
1092 			ubi->ubi_name, ubi->ref_count);
1093 	}
1094 	ubi_devices[ubi_num] = NULL;
1095 	spin_unlock(&ubi_devices_lock);
1096 
1097 	ubi_assert(ubi_num == ubi->ubi_num);
1098 	ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
1099 	ubi_msg(ubi, "detaching mtd%d", ubi->mtd->index);
1100 #ifdef CONFIG_MTD_UBI_FASTMAP
1101 	/* If we don't write a new fastmap at detach time we lose all
1102 	 * EC updates that have been made since the last written fastmap.
1103 	 * In case of fastmap debugging we omit the update to simulate an
1104 	 * unclean shutdown. */
1105 	if (!ubi_dbg_chk_fastmap(ubi))
1106 		ubi_update_fastmap(ubi);
1107 #endif
1108 	/*
1109 	 * Before freeing anything, we have to stop the background thread to
1110 	 * prevent it from doing anything on this device while we are freeing.
1111 	 */
1112 	if (ubi->bgt_thread)
1113 		kthread_stop(ubi->bgt_thread);
1114 
1115 	/*
1116 	 * Get a reference to the device in order to prevent 'dev_release()'
1117 	 * from freeing the @ubi object.
1118 	 */
1119 	get_device(&ubi->dev);
1120 
1121 	ubi_debugfs_exit_dev(ubi);
1122 	uif_close(ubi);
1123 
1124 	ubi_wl_close(ubi);
1125 	ubi_free_internal_volumes(ubi);
1126 	vfree(ubi->vtbl);
1127 	put_mtd_device(ubi->mtd);
1128 	vfree(ubi->peb_buf);
1129 	vfree(ubi->fm_buf);
1130 	ubi_msg(ubi, "mtd%d is detached", ubi->mtd->index);
1131 	put_device(&ubi->dev);
1132 	return 0;
1133 }
1134 
1135 /**
1136  * open_mtd_by_chdev - open an MTD device by its character device node path.
1137  * @mtd_dev: MTD character device node path
1138  *
1139  * This helper function opens an MTD device by its character node device path.
1140  * Returns MTD device description object in case of success and a negative
1141  * error code in case of failure.
1142  */
1143 static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
1144 {
1145 	int err, major, minor, mode;
1146 	struct path path;
1147 
1148 	/* Probably this is an MTD character device node path */
1149 	err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
1150 	if (err)
1151 		return ERR_PTR(err);
1152 
1153 	/* MTD device number is defined by the major / minor numbers */
1154 	major = imajor(d_backing_inode(path.dentry));
1155 	minor = iminor(d_backing_inode(path.dentry));
1156 	mode = d_backing_inode(path.dentry)->i_mode;
1157 	path_put(&path);
1158 	if (major != MTD_CHAR_MAJOR || !S_ISCHR(mode))
1159 		return ERR_PTR(-EINVAL);
1160 
1161 	if (minor & 1)
1162 		/*
1163 		 * Just do not think the "/dev/mtdrX" devices support is need,
1164 		 * so do not support them to avoid doing extra work.
1165 		 */
1166 		return ERR_PTR(-EINVAL);
1167 
1168 	return get_mtd_device(NULL, minor / 2);
1169 }
1170 
1171 /**
1172  * open_mtd_device - open MTD device by name, character device path, or number.
1173  * @mtd_dev: name, character device node path, or MTD device device number
1174  *
1175  * This function tries to open and MTD device described by @mtd_dev string,
1176  * which is first treated as ASCII MTD device number, and if it is not true, it
1177  * is treated as MTD device name, and if that is also not true, it is treated
1178  * as MTD character device node path. Returns MTD device description object in
1179  * case of success and a negative error code in case of failure.
1180  */
1181 static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
1182 {
1183 	struct mtd_info *mtd;
1184 	int mtd_num;
1185 	char *endp;
1186 
1187 	mtd_num = simple_strtoul(mtd_dev, &endp, 0);
1188 	if (*endp != '\0' || mtd_dev == endp) {
1189 		/*
1190 		 * This does not look like an ASCII integer, probably this is
1191 		 * MTD device name.
1192 		 */
1193 		mtd = get_mtd_device_nm(mtd_dev);
1194 		if (IS_ERR(mtd) && PTR_ERR(mtd) == -ENODEV)
1195 			/* Probably this is an MTD character device node path */
1196 			mtd = open_mtd_by_chdev(mtd_dev);
1197 	} else
1198 		mtd = get_mtd_device(NULL, mtd_num);
1199 
1200 	return mtd;
1201 }
1202 
1203 static int __init ubi_init(void)
1204 {
1205 	int err, i, k;
1206 
1207 	/* Ensure that EC and VID headers have correct size */
1208 	BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
1209 	BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);
1210 
1211 	if (mtd_devs > UBI_MAX_DEVICES) {
1212 		pr_err("UBI error: too many MTD devices, maximum is %d",
1213 		       UBI_MAX_DEVICES);
1214 		return -EINVAL;
1215 	}
1216 
1217 	/* Create base sysfs directory and sysfs files */
1218 	err = class_register(&ubi_class);
1219 	if (err < 0)
1220 		return err;
1221 
1222 	err = misc_register(&ubi_ctrl_cdev);
1223 	if (err) {
1224 		pr_err("UBI error: cannot register device");
1225 		goto out;
1226 	}
1227 
1228 	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
1229 					      sizeof(struct ubi_wl_entry),
1230 					      0, 0, NULL);
1231 	if (!ubi_wl_entry_slab) {
1232 		err = -ENOMEM;
1233 		goto out_dev_unreg;
1234 	}
1235 
1236 	err = ubi_debugfs_init();
1237 	if (err)
1238 		goto out_slab;
1239 
1240 
1241 	/* Attach MTD devices */
1242 	for (i = 0; i < mtd_devs; i++) {
1243 		struct mtd_dev_param *p = &mtd_dev_param[i];
1244 		struct mtd_info *mtd;
1245 
1246 		cond_resched();
1247 
1248 		mtd = open_mtd_device(p->name);
1249 		if (IS_ERR(mtd)) {
1250 			err = PTR_ERR(mtd);
1251 			pr_err("UBI error: cannot open mtd %s, error %d",
1252 			       p->name, err);
1253 			/* See comment below re-ubi_is_module(). */
1254 			if (ubi_is_module())
1255 				goto out_detach;
1256 			continue;
1257 		}
1258 
1259 		mutex_lock(&ubi_devices_mutex);
1260 		err = ubi_attach_mtd_dev(mtd, p->ubi_num,
1261 					 p->vid_hdr_offs, p->max_beb_per1024);
1262 		mutex_unlock(&ubi_devices_mutex);
1263 		if (err < 0) {
1264 			pr_err("UBI error: cannot attach mtd%d",
1265 			       mtd->index);
1266 			put_mtd_device(mtd);
1267 
1268 			/*
1269 			 * Originally UBI stopped initializing on any error.
1270 			 * However, later on it was found out that this
1271 			 * behavior is not very good when UBI is compiled into
1272 			 * the kernel and the MTD devices to attach are passed
1273 			 * through the command line. Indeed, UBI failure
1274 			 * stopped whole boot sequence.
1275 			 *
1276 			 * To fix this, we changed the behavior for the
1277 			 * non-module case, but preserved the old behavior for
1278 			 * the module case, just for compatibility. This is a
1279 			 * little inconsistent, though.
1280 			 */
1281 			if (ubi_is_module())
1282 				goto out_detach;
1283 		}
1284 	}
1285 
1286 	err = ubiblock_init();
1287 	if (err) {
1288 		pr_err("UBI error: block: cannot initialize, error %d", err);
1289 
1290 		/* See comment above re-ubi_is_module(). */
1291 		if (ubi_is_module())
1292 			goto out_detach;
1293 	}
1294 
1295 	return 0;
1296 
1297 out_detach:
1298 	for (k = 0; k < i; k++)
1299 		if (ubi_devices[k]) {
1300 			mutex_lock(&ubi_devices_mutex);
1301 			ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
1302 			mutex_unlock(&ubi_devices_mutex);
1303 		}
1304 	ubi_debugfs_exit();
1305 out_slab:
1306 	kmem_cache_destroy(ubi_wl_entry_slab);
1307 out_dev_unreg:
1308 	misc_deregister(&ubi_ctrl_cdev);
1309 out:
1310 	class_unregister(&ubi_class);
1311 	pr_err("UBI error: cannot initialize UBI, error %d", err);
1312 	return err;
1313 }
1314 late_initcall(ubi_init);
1315 
1316 static void __exit ubi_exit(void)
1317 {
1318 	int i;
1319 
1320 	ubiblock_exit();
1321 
1322 	for (i = 0; i < UBI_MAX_DEVICES; i++)
1323 		if (ubi_devices[i]) {
1324 			mutex_lock(&ubi_devices_mutex);
1325 			ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
1326 			mutex_unlock(&ubi_devices_mutex);
1327 		}
1328 	ubi_debugfs_exit();
1329 	kmem_cache_destroy(ubi_wl_entry_slab);
1330 	misc_deregister(&ubi_ctrl_cdev);
1331 	class_unregister(&ubi_class);
1332 }
1333 module_exit(ubi_exit);
1334 
1335 /**
1336  * bytes_str_to_int - convert a number of bytes string into an integer.
1337  * @str: the string to convert
1338  *
1339  * This function returns positive resulting integer in case of success and a
1340  * negative error code in case of failure.
1341  */
1342 static int __init bytes_str_to_int(const char *str)
1343 {
1344 	char *endp;
1345 	unsigned long result;
1346 
1347 	result = simple_strtoul(str, &endp, 0);
1348 	if (str == endp || result >= INT_MAX) {
1349 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1350 		return -EINVAL;
1351 	}
1352 
1353 	switch (*endp) {
1354 	case 'G':
1355 		result *= 1024;
1356 	case 'M':
1357 		result *= 1024;
1358 	case 'K':
1359 		result *= 1024;
1360 		if (endp[1] == 'i' && endp[2] == 'B')
1361 			endp += 2;
1362 	case '\0':
1363 		break;
1364 	default:
1365 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1366 		return -EINVAL;
1367 	}
1368 
1369 	return result;
1370 }
1371 
1372 /**
1373  * ubi_mtd_param_parse - parse the 'mtd=' UBI parameter.
1374  * @val: the parameter value to parse
1375  * @kp: not used
1376  *
1377  * This function returns zero in case of success and a negative error code in
1378  * case of error.
1379  */
1380 static int __init ubi_mtd_param_parse(const char *val, struct kernel_param *kp)
1381 {
1382 	int i, len;
1383 	struct mtd_dev_param *p;
1384 	char buf[MTD_PARAM_LEN_MAX];
1385 	char *pbuf = &buf[0];
1386 	char *tokens[MTD_PARAM_MAX_COUNT], *token;
1387 
1388 	if (!val)
1389 		return -EINVAL;
1390 
1391 	if (mtd_devs == UBI_MAX_DEVICES) {
1392 		pr_err("UBI error: too many parameters, max. is %d\n",
1393 		       UBI_MAX_DEVICES);
1394 		return -EINVAL;
1395 	}
1396 
1397 	len = strnlen(val, MTD_PARAM_LEN_MAX);
1398 	if (len == MTD_PARAM_LEN_MAX) {
1399 		pr_err("UBI error: parameter \"%s\" is too long, max. is %d\n",
1400 		       val, MTD_PARAM_LEN_MAX);
1401 		return -EINVAL;
1402 	}
1403 
1404 	if (len == 0) {
1405 		pr_warn("UBI warning: empty 'mtd=' parameter - ignored\n");
1406 		return 0;
1407 	}
1408 
1409 	strcpy(buf, val);
1410 
1411 	/* Get rid of the final newline */
1412 	if (buf[len - 1] == '\n')
1413 		buf[len - 1] = '\0';
1414 
1415 	for (i = 0; i < MTD_PARAM_MAX_COUNT; i++)
1416 		tokens[i] = strsep(&pbuf, ",");
1417 
1418 	if (pbuf) {
1419 		pr_err("UBI error: too many arguments at \"%s\"\n", val);
1420 		return -EINVAL;
1421 	}
1422 
1423 	p = &mtd_dev_param[mtd_devs];
1424 	strcpy(&p->name[0], tokens[0]);
1425 
1426 	token = tokens[1];
1427 	if (token) {
1428 		p->vid_hdr_offs = bytes_str_to_int(token);
1429 
1430 		if (p->vid_hdr_offs < 0)
1431 			return p->vid_hdr_offs;
1432 	}
1433 
1434 	token = tokens[2];
1435 	if (token) {
1436 		int err = kstrtoint(token, 10, &p->max_beb_per1024);
1437 
1438 		if (err) {
1439 			pr_err("UBI error: bad value for max_beb_per1024 parameter: %s",
1440 			       token);
1441 			return -EINVAL;
1442 		}
1443 	}
1444 
1445 	token = tokens[3];
1446 	if (token) {
1447 		int err = kstrtoint(token, 10, &p->ubi_num);
1448 
1449 		if (err) {
1450 			pr_err("UBI error: bad value for ubi_num parameter: %s",
1451 			       token);
1452 			return -EINVAL;
1453 		}
1454 	} else
1455 		p->ubi_num = UBI_DEV_NUM_AUTO;
1456 
1457 	mtd_devs += 1;
1458 	return 0;
1459 }
1460 
1461 module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 000);
1462 MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024[,ubi_num]]].\n"
1463 		      "Multiple \"mtd\" parameters may be specified.\n"
1464 		      "MTD devices may be specified by their number, name, or path to the MTD character device node.\n"
1465 		      "Optional \"vid_hdr_offs\" parameter specifies UBI VID header position to be used by UBI. (default value if 0)\n"
1466 		      "Optional \"max_beb_per1024\" parameter specifies the maximum expected bad eraseblock per 1024 eraseblocks. (default value ("
1467 		      __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0)\n"
1468 		      "Optional \"ubi_num\" parameter specifies UBI device number which have to be assigned to the newly created UBI device (assigned automatically by default)\n"
1469 		      "\n"
1470 		      "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
1471 		      "Example 2: mtd=content,1984 mtd=4 - attach MTD device with name \"content\" using VID header offset 1984, and MTD device number 4 with default VID header offset.\n"
1472 		      "Example 3: mtd=/dev/mtd1,0,25 - attach MTD device /dev/mtd1 using default VID header offset and reserve 25*nand_size_in_blocks/1024 erase blocks for bad block handling.\n"
1473 		      "Example 4: mtd=/dev/mtd1,0,0,5 - attach MTD device /dev/mtd1 to UBI 5 and using default values for the other fields.\n"
1474 		      "\t(e.g. if the NAND *chipset* has 4096 PEB, 100 will be reserved for this UBI device).");
1475 #ifdef CONFIG_MTD_UBI_FASTMAP
1476 module_param(fm_autoconvert, bool, 0644);
1477 MODULE_PARM_DESC(fm_autoconvert, "Set this parameter to enable fastmap automatically on images without a fastmap.");
1478 module_param(fm_debug, bool, 0);
1479 MODULE_PARM_DESC(fm_debug, "Set this parameter to enable fastmap debugging by default. Warning, this will make fastmap slow!");
1480 #endif
1481 MODULE_VERSION(__stringify(UBI_VERSION));
1482 MODULE_DESCRIPTION("UBI - Unsorted Block Images");
1483 MODULE_AUTHOR("Artem Bityutskiy");
1484 MODULE_LICENSE("GPL");
1485