xref: /openbmc/linux/drivers/mtd/ubi/build.c (revision 8fdff1dc)
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 "ubi.h"
45 
46 /* Maximum length of the 'mtd=' parameter */
47 #define MTD_PARAM_LEN_MAX 64
48 
49 /* Maximum number of comma-separated items in the 'mtd=' parameter */
50 #define MTD_PARAM_MAX_COUNT 3
51 
52 /* Maximum value for the number of bad PEBs per 1024 PEBs */
53 #define MAX_MTD_UBI_BEB_LIMIT 768
54 
55 #ifdef CONFIG_MTD_UBI_MODULE
56 #define ubi_is_module() 1
57 #else
58 #define ubi_is_module() 0
59 #endif
60 
61 /**
62  * struct mtd_dev_param - MTD device parameter description data structure.
63  * @name: MTD character device node path, MTD device name, or MTD device number
64  *        string
65  * @vid_hdr_offs: VID header offset
66  * @max_beb_per1024: maximum expected number of bad PEBs per 1024 PEBs
67  */
68 struct mtd_dev_param {
69 	char name[MTD_PARAM_LEN_MAX];
70 	int vid_hdr_offs;
71 	int max_beb_per1024;
72 };
73 
74 /* Numbers of elements set in the @mtd_dev_param array */
75 static int __initdata mtd_devs;
76 
77 /* MTD devices specification parameters */
78 static struct mtd_dev_param __initdata mtd_dev_param[UBI_MAX_DEVICES];
79 #ifdef CONFIG_MTD_UBI_FASTMAP
80 /* UBI module parameter to enable fastmap automatically on non-fastmap images */
81 static bool fm_autoconvert;
82 #endif
83 /* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
84 struct class *ubi_class;
85 
86 /* Slab cache for wear-leveling entries */
87 struct kmem_cache *ubi_wl_entry_slab;
88 
89 /* UBI control character device */
90 static struct miscdevice ubi_ctrl_cdev = {
91 	.minor = MISC_DYNAMIC_MINOR,
92 	.name = "ubi_ctrl",
93 	.fops = &ubi_ctrl_cdev_operations,
94 };
95 
96 /* All UBI devices in system */
97 static struct ubi_device *ubi_devices[UBI_MAX_DEVICES];
98 
99 /* Serializes UBI devices creations and removals */
100 DEFINE_MUTEX(ubi_devices_mutex);
101 
102 /* Protects @ubi_devices and @ubi->ref_count */
103 static DEFINE_SPINLOCK(ubi_devices_lock);
104 
105 /* "Show" method for files in '/<sysfs>/class/ubi/' */
106 static ssize_t ubi_version_show(struct class *class,
107 				struct class_attribute *attr, char *buf)
108 {
109 	return sprintf(buf, "%d\n", UBI_VERSION);
110 }
111 
112 /* UBI version attribute ('/<sysfs>/class/ubi/version') */
113 static struct class_attribute ubi_version =
114 	__ATTR(version, S_IRUGO, ubi_version_show, NULL);
115 
116 static ssize_t dev_attribute_show(struct device *dev,
117 				  struct device_attribute *attr, char *buf);
118 
119 /* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
120 static struct device_attribute dev_eraseblock_size =
121 	__ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
122 static struct device_attribute dev_avail_eraseblocks =
123 	__ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
124 static struct device_attribute dev_total_eraseblocks =
125 	__ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
126 static struct device_attribute dev_volumes_count =
127 	__ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
128 static struct device_attribute dev_max_ec =
129 	__ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
130 static struct device_attribute dev_reserved_for_bad =
131 	__ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
132 static struct device_attribute dev_bad_peb_count =
133 	__ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
134 static struct device_attribute dev_max_vol_count =
135 	__ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
136 static struct device_attribute dev_min_io_size =
137 	__ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
138 static struct device_attribute dev_bgt_enabled =
139 	__ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);
140 static struct device_attribute dev_mtd_num =
141 	__ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
142 
143 /**
144  * ubi_volume_notify - send a volume change notification.
145  * @ubi: UBI device description object
146  * @vol: volume description object of the changed volume
147  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
148  *
149  * This is a helper function which notifies all subscribers about a volume
150  * change event (creation, removal, re-sizing, re-naming, updating). Returns
151  * zero in case of success and a negative error code in case of failure.
152  */
153 int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
154 {
155 	struct ubi_notification nt;
156 
157 	ubi_do_get_device_info(ubi, &nt.di);
158 	ubi_do_get_volume_info(ubi, vol, &nt.vi);
159 
160 #ifdef CONFIG_MTD_UBI_FASTMAP
161 	switch (ntype) {
162 	case UBI_VOLUME_ADDED:
163 	case UBI_VOLUME_REMOVED:
164 	case UBI_VOLUME_RESIZED:
165 	case UBI_VOLUME_RENAMED:
166 		if (ubi_update_fastmap(ubi)) {
167 			ubi_err("Unable to update fastmap!");
168 			ubi_ro_mode(ubi);
169 		}
170 	}
171 #endif
172 	return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
173 }
174 
175 /**
176  * ubi_notify_all - send a notification to all volumes.
177  * @ubi: UBI device description object
178  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
179  * @nb: the notifier to call
180  *
181  * This function walks all volumes of UBI device @ubi and sends the @ntype
182  * notification for each volume. If @nb is %NULL, then all registered notifiers
183  * are called, otherwise only the @nb notifier is called. Returns the number of
184  * sent notifications.
185  */
186 int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
187 {
188 	struct ubi_notification nt;
189 	int i, count = 0;
190 
191 	ubi_do_get_device_info(ubi, &nt.di);
192 
193 	mutex_lock(&ubi->device_mutex);
194 	for (i = 0; i < ubi->vtbl_slots; i++) {
195 		/*
196 		 * Since the @ubi->device is locked, and we are not going to
197 		 * change @ubi->volumes, we do not have to lock
198 		 * @ubi->volumes_lock.
199 		 */
200 		if (!ubi->volumes[i])
201 			continue;
202 
203 		ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
204 		if (nb)
205 			nb->notifier_call(nb, ntype, &nt);
206 		else
207 			blocking_notifier_call_chain(&ubi_notifiers, ntype,
208 						     &nt);
209 		count += 1;
210 	}
211 	mutex_unlock(&ubi->device_mutex);
212 
213 	return count;
214 }
215 
216 /**
217  * ubi_enumerate_volumes - send "add" notification for all existing volumes.
218  * @nb: the notifier to call
219  *
220  * This function walks all UBI devices and volumes and sends the
221  * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
222  * registered notifiers are called, otherwise only the @nb notifier is called.
223  * Returns the number of sent notifications.
224  */
225 int ubi_enumerate_volumes(struct notifier_block *nb)
226 {
227 	int i, count = 0;
228 
229 	/*
230 	 * Since the @ubi_devices_mutex is locked, and we are not going to
231 	 * change @ubi_devices, we do not have to lock @ubi_devices_lock.
232 	 */
233 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
234 		struct ubi_device *ubi = ubi_devices[i];
235 
236 		if (!ubi)
237 			continue;
238 		count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
239 	}
240 
241 	return count;
242 }
243 
244 /**
245  * ubi_get_device - get UBI device.
246  * @ubi_num: UBI device number
247  *
248  * This function returns UBI device description object for UBI device number
249  * @ubi_num, or %NULL if the device does not exist. This function increases the
250  * device reference count to prevent removal of the device. In other words, the
251  * device cannot be removed if its reference count is not zero.
252  */
253 struct ubi_device *ubi_get_device(int ubi_num)
254 {
255 	struct ubi_device *ubi;
256 
257 	spin_lock(&ubi_devices_lock);
258 	ubi = ubi_devices[ubi_num];
259 	if (ubi) {
260 		ubi_assert(ubi->ref_count >= 0);
261 		ubi->ref_count += 1;
262 		get_device(&ubi->dev);
263 	}
264 	spin_unlock(&ubi_devices_lock);
265 
266 	return ubi;
267 }
268 
269 /**
270  * ubi_put_device - drop an UBI device reference.
271  * @ubi: UBI device description object
272  */
273 void ubi_put_device(struct ubi_device *ubi)
274 {
275 	spin_lock(&ubi_devices_lock);
276 	ubi->ref_count -= 1;
277 	put_device(&ubi->dev);
278 	spin_unlock(&ubi_devices_lock);
279 }
280 
281 /**
282  * ubi_get_by_major - get UBI device by character device major number.
283  * @major: major number
284  *
285  * This function is similar to 'ubi_get_device()', but it searches the device
286  * by its major number.
287  */
288 struct ubi_device *ubi_get_by_major(int major)
289 {
290 	int i;
291 	struct ubi_device *ubi;
292 
293 	spin_lock(&ubi_devices_lock);
294 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
295 		ubi = ubi_devices[i];
296 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
297 			ubi_assert(ubi->ref_count >= 0);
298 			ubi->ref_count += 1;
299 			get_device(&ubi->dev);
300 			spin_unlock(&ubi_devices_lock);
301 			return ubi;
302 		}
303 	}
304 	spin_unlock(&ubi_devices_lock);
305 
306 	return NULL;
307 }
308 
309 /**
310  * ubi_major2num - get UBI device number by character device major number.
311  * @major: major number
312  *
313  * This function searches UBI device number object by its major number. If UBI
314  * device was not found, this function returns -ENODEV, otherwise the UBI device
315  * number is returned.
316  */
317 int ubi_major2num(int major)
318 {
319 	int i, ubi_num = -ENODEV;
320 
321 	spin_lock(&ubi_devices_lock);
322 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
323 		struct ubi_device *ubi = ubi_devices[i];
324 
325 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
326 			ubi_num = ubi->ubi_num;
327 			break;
328 		}
329 	}
330 	spin_unlock(&ubi_devices_lock);
331 
332 	return ubi_num;
333 }
334 
335 /* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
336 static ssize_t dev_attribute_show(struct device *dev,
337 				  struct device_attribute *attr, char *buf)
338 {
339 	ssize_t ret;
340 	struct ubi_device *ubi;
341 
342 	/*
343 	 * The below code looks weird, but it actually makes sense. We get the
344 	 * UBI device reference from the contained 'struct ubi_device'. But it
345 	 * is unclear if the device was removed or not yet. Indeed, if the
346 	 * device was removed before we increased its reference count,
347 	 * 'ubi_get_device()' will return -ENODEV and we fail.
348 	 *
349 	 * Remember, 'struct ubi_device' is freed in the release function, so
350 	 * we still can use 'ubi->ubi_num'.
351 	 */
352 	ubi = container_of(dev, struct ubi_device, dev);
353 	ubi = ubi_get_device(ubi->ubi_num);
354 	if (!ubi)
355 		return -ENODEV;
356 
357 	if (attr == &dev_eraseblock_size)
358 		ret = sprintf(buf, "%d\n", ubi->leb_size);
359 	else if (attr == &dev_avail_eraseblocks)
360 		ret = sprintf(buf, "%d\n", ubi->avail_pebs);
361 	else if (attr == &dev_total_eraseblocks)
362 		ret = sprintf(buf, "%d\n", ubi->good_peb_count);
363 	else if (attr == &dev_volumes_count)
364 		ret = sprintf(buf, "%d\n", ubi->vol_count - UBI_INT_VOL_COUNT);
365 	else if (attr == &dev_max_ec)
366 		ret = sprintf(buf, "%d\n", ubi->max_ec);
367 	else if (attr == &dev_reserved_for_bad)
368 		ret = sprintf(buf, "%d\n", ubi->beb_rsvd_pebs);
369 	else if (attr == &dev_bad_peb_count)
370 		ret = sprintf(buf, "%d\n", ubi->bad_peb_count);
371 	else if (attr == &dev_max_vol_count)
372 		ret = sprintf(buf, "%d\n", ubi->vtbl_slots);
373 	else if (attr == &dev_min_io_size)
374 		ret = sprintf(buf, "%d\n", ubi->min_io_size);
375 	else if (attr == &dev_bgt_enabled)
376 		ret = sprintf(buf, "%d\n", ubi->thread_enabled);
377 	else if (attr == &dev_mtd_num)
378 		ret = sprintf(buf, "%d\n", ubi->mtd->index);
379 	else
380 		ret = -EINVAL;
381 
382 	ubi_put_device(ubi);
383 	return ret;
384 }
385 
386 static void dev_release(struct device *dev)
387 {
388 	struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);
389 
390 	kfree(ubi);
391 }
392 
393 /**
394  * ubi_sysfs_init - initialize sysfs for an UBI device.
395  * @ubi: UBI device description object
396  * @ref: set to %1 on exit in case of failure if a reference to @ubi->dev was
397  *       taken
398  *
399  * This function returns zero in case of success and a negative error code in
400  * case of failure.
401  */
402 static int ubi_sysfs_init(struct ubi_device *ubi, int *ref)
403 {
404 	int err;
405 
406 	ubi->dev.release = dev_release;
407 	ubi->dev.devt = ubi->cdev.dev;
408 	ubi->dev.class = ubi_class;
409 	dev_set_name(&ubi->dev, UBI_NAME_STR"%d", ubi->ubi_num);
410 	err = device_register(&ubi->dev);
411 	if (err)
412 		return err;
413 
414 	*ref = 1;
415 	err = device_create_file(&ubi->dev, &dev_eraseblock_size);
416 	if (err)
417 		return err;
418 	err = device_create_file(&ubi->dev, &dev_avail_eraseblocks);
419 	if (err)
420 		return err;
421 	err = device_create_file(&ubi->dev, &dev_total_eraseblocks);
422 	if (err)
423 		return err;
424 	err = device_create_file(&ubi->dev, &dev_volumes_count);
425 	if (err)
426 		return err;
427 	err = device_create_file(&ubi->dev, &dev_max_ec);
428 	if (err)
429 		return err;
430 	err = device_create_file(&ubi->dev, &dev_reserved_for_bad);
431 	if (err)
432 		return err;
433 	err = device_create_file(&ubi->dev, &dev_bad_peb_count);
434 	if (err)
435 		return err;
436 	err = device_create_file(&ubi->dev, &dev_max_vol_count);
437 	if (err)
438 		return err;
439 	err = device_create_file(&ubi->dev, &dev_min_io_size);
440 	if (err)
441 		return err;
442 	err = device_create_file(&ubi->dev, &dev_bgt_enabled);
443 	if (err)
444 		return err;
445 	err = device_create_file(&ubi->dev, &dev_mtd_num);
446 	return err;
447 }
448 
449 /**
450  * ubi_sysfs_close - close sysfs for an UBI device.
451  * @ubi: UBI device description object
452  */
453 static void ubi_sysfs_close(struct ubi_device *ubi)
454 {
455 	device_remove_file(&ubi->dev, &dev_mtd_num);
456 	device_remove_file(&ubi->dev, &dev_bgt_enabled);
457 	device_remove_file(&ubi->dev, &dev_min_io_size);
458 	device_remove_file(&ubi->dev, &dev_max_vol_count);
459 	device_remove_file(&ubi->dev, &dev_bad_peb_count);
460 	device_remove_file(&ubi->dev, &dev_reserved_for_bad);
461 	device_remove_file(&ubi->dev, &dev_max_ec);
462 	device_remove_file(&ubi->dev, &dev_volumes_count);
463 	device_remove_file(&ubi->dev, &dev_total_eraseblocks);
464 	device_remove_file(&ubi->dev, &dev_avail_eraseblocks);
465 	device_remove_file(&ubi->dev, &dev_eraseblock_size);
466 	device_unregister(&ubi->dev);
467 }
468 
469 /**
470  * kill_volumes - destroy all user volumes.
471  * @ubi: UBI device description object
472  */
473 static void kill_volumes(struct ubi_device *ubi)
474 {
475 	int i;
476 
477 	for (i = 0; i < ubi->vtbl_slots; i++)
478 		if (ubi->volumes[i])
479 			ubi_free_volume(ubi, ubi->volumes[i]);
480 }
481 
482 /**
483  * uif_init - initialize user interfaces for an UBI device.
484  * @ubi: UBI device description object
485  * @ref: set to %1 on exit in case of failure if a reference to @ubi->dev was
486  *       taken, otherwise set to %0
487  *
488  * This function initializes various user interfaces for an UBI device. If the
489  * initialization fails at an early stage, this function frees all the
490  * resources it allocated, returns an error, and @ref is set to %0. However,
491  * if the initialization fails after the UBI device was registered in the
492  * driver core subsystem, this function takes a reference to @ubi->dev, because
493  * otherwise the release function ('dev_release()') would free whole @ubi
494  * object. The @ref argument is set to %1 in this case. The caller has to put
495  * this reference.
496  *
497  * This function returns zero in case of success and a negative error code in
498  * case of failure.
499  */
500 static int uif_init(struct ubi_device *ubi, int *ref)
501 {
502 	int i, err;
503 	dev_t dev;
504 
505 	*ref = 0;
506 	sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);
507 
508 	/*
509 	 * Major numbers for the UBI character devices are allocated
510 	 * dynamically. Major numbers of volume character devices are
511 	 * equivalent to ones of the corresponding UBI character device. Minor
512 	 * numbers of UBI character devices are 0, while minor numbers of
513 	 * volume character devices start from 1. Thus, we allocate one major
514 	 * number and ubi->vtbl_slots + 1 minor numbers.
515 	 */
516 	err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
517 	if (err) {
518 		ubi_err("cannot register UBI character devices");
519 		return err;
520 	}
521 
522 	ubi_assert(MINOR(dev) == 0);
523 	cdev_init(&ubi->cdev, &ubi_cdev_operations);
524 	dbg_gen("%s major is %u", ubi->ubi_name, MAJOR(dev));
525 	ubi->cdev.owner = THIS_MODULE;
526 
527 	err = cdev_add(&ubi->cdev, dev, 1);
528 	if (err) {
529 		ubi_err("cannot add character device");
530 		goto out_unreg;
531 	}
532 
533 	err = ubi_sysfs_init(ubi, ref);
534 	if (err)
535 		goto out_sysfs;
536 
537 	for (i = 0; i < ubi->vtbl_slots; i++)
538 		if (ubi->volumes[i]) {
539 			err = ubi_add_volume(ubi, ubi->volumes[i]);
540 			if (err) {
541 				ubi_err("cannot add volume %d", i);
542 				goto out_volumes;
543 			}
544 		}
545 
546 	return 0;
547 
548 out_volumes:
549 	kill_volumes(ubi);
550 out_sysfs:
551 	if (*ref)
552 		get_device(&ubi->dev);
553 	ubi_sysfs_close(ubi);
554 	cdev_del(&ubi->cdev);
555 out_unreg:
556 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
557 	ubi_err("cannot initialize UBI %s, error %d", ubi->ubi_name, err);
558 	return err;
559 }
560 
561 /**
562  * uif_close - close user interfaces for an UBI device.
563  * @ubi: UBI device description object
564  *
565  * Note, since this function un-registers UBI volume device objects (@vol->dev),
566  * the memory allocated voe the volumes is freed as well (in the release
567  * function).
568  */
569 static void uif_close(struct ubi_device *ubi)
570 {
571 	kill_volumes(ubi);
572 	ubi_sysfs_close(ubi);
573 	cdev_del(&ubi->cdev);
574 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
575 }
576 
577 /**
578  * ubi_free_internal_volumes - free internal volumes.
579  * @ubi: UBI device description object
580  */
581 void ubi_free_internal_volumes(struct ubi_device *ubi)
582 {
583 	int i;
584 
585 	for (i = ubi->vtbl_slots;
586 	     i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
587 		kfree(ubi->volumes[i]->eba_tbl);
588 		kfree(ubi->volumes[i]);
589 	}
590 }
591 
592 static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
593 {
594 	int limit, device_pebs;
595 	uint64_t device_size;
596 
597 	if (!max_beb_per1024)
598 		return 0;
599 
600 	/*
601 	 * Here we are using size of the entire flash chip and
602 	 * not just the MTD partition size because the maximum
603 	 * number of bad eraseblocks is a percentage of the
604 	 * whole device and bad eraseblocks are not fairly
605 	 * distributed over the flash chip. So the worst case
606 	 * is that all the bad eraseblocks of the chip are in
607 	 * the MTD partition we are attaching (ubi->mtd).
608 	 */
609 	device_size = mtd_get_device_size(ubi->mtd);
610 	device_pebs = mtd_div_by_eb(device_size, ubi->mtd);
611 	limit = mult_frac(device_pebs, max_beb_per1024, 1024);
612 
613 	/* Round it up */
614 	if (mult_frac(limit, 1024, max_beb_per1024) < device_pebs)
615 		limit += 1;
616 
617 	return limit;
618 }
619 
620 /**
621  * io_init - initialize I/O sub-system for a given UBI device.
622  * @ubi: UBI device description object
623  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
624  *
625  * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
626  * assumed:
627  *   o EC header is always at offset zero - this cannot be changed;
628  *   o VID header starts just after the EC header at the closest address
629  *     aligned to @io->hdrs_min_io_size;
630  *   o data starts just after the VID header at the closest address aligned to
631  *     @io->min_io_size
632  *
633  * This function returns zero in case of success and a negative error code in
634  * case of failure.
635  */
636 static int io_init(struct ubi_device *ubi, int max_beb_per1024)
637 {
638 	dbg_gen("sizeof(struct ubi_ainf_peb) %zu", sizeof(struct ubi_ainf_peb));
639 	dbg_gen("sizeof(struct ubi_wl_entry) %zu", sizeof(struct ubi_wl_entry));
640 
641 	if (ubi->mtd->numeraseregions != 0) {
642 		/*
643 		 * Some flashes have several erase regions. Different regions
644 		 * may have different eraseblock size and other
645 		 * characteristics. It looks like mostly multi-region flashes
646 		 * have one "main" region and one or more small regions to
647 		 * store boot loader code or boot parameters or whatever. I
648 		 * guess we should just pick the largest region. But this is
649 		 * not implemented.
650 		 */
651 		ubi_err("multiple regions, not implemented");
652 		return -EINVAL;
653 	}
654 
655 	if (ubi->vid_hdr_offset < 0)
656 		return -EINVAL;
657 
658 	/*
659 	 * Note, in this implementation we support MTD devices with 0x7FFFFFFF
660 	 * physical eraseblocks maximum.
661 	 */
662 
663 	ubi->peb_size   = ubi->mtd->erasesize;
664 	ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
665 	ubi->flash_size = ubi->mtd->size;
666 
667 	if (mtd_can_have_bb(ubi->mtd)) {
668 		ubi->bad_allowed = 1;
669 		ubi->bad_peb_limit = get_bad_peb_limit(ubi, max_beb_per1024);
670 	}
671 
672 	if (ubi->mtd->type == MTD_NORFLASH) {
673 		ubi_assert(ubi->mtd->writesize == 1);
674 		ubi->nor_flash = 1;
675 	}
676 
677 	ubi->min_io_size = ubi->mtd->writesize;
678 	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
679 
680 	/*
681 	 * Make sure minimal I/O unit is power of 2. Note, there is no
682 	 * fundamental reason for this assumption. It is just an optimization
683 	 * which allows us to avoid costly division operations.
684 	 */
685 	if (!is_power_of_2(ubi->min_io_size)) {
686 		ubi_err("min. I/O unit (%d) is not power of 2",
687 			ubi->min_io_size);
688 		return -EINVAL;
689 	}
690 
691 	ubi_assert(ubi->hdrs_min_io_size > 0);
692 	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
693 	ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
694 
695 	ubi->max_write_size = ubi->mtd->writebufsize;
696 	/*
697 	 * Maximum write size has to be greater or equivalent to min. I/O
698 	 * size, and be multiple of min. I/O size.
699 	 */
700 	if (ubi->max_write_size < ubi->min_io_size ||
701 	    ubi->max_write_size % ubi->min_io_size ||
702 	    !is_power_of_2(ubi->max_write_size)) {
703 		ubi_err("bad write buffer size %d for %d min. I/O unit",
704 			ubi->max_write_size, ubi->min_io_size);
705 		return -EINVAL;
706 	}
707 
708 	/* Calculate default aligned sizes of EC and VID headers */
709 	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
710 	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
711 
712 	dbg_gen("min_io_size      %d", ubi->min_io_size);
713 	dbg_gen("max_write_size   %d", ubi->max_write_size);
714 	dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
715 	dbg_gen("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
716 	dbg_gen("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
717 
718 	if (ubi->vid_hdr_offset == 0)
719 		/* Default offset */
720 		ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
721 				      ubi->ec_hdr_alsize;
722 	else {
723 		ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
724 						~(ubi->hdrs_min_io_size - 1);
725 		ubi->vid_hdr_shift = ubi->vid_hdr_offset -
726 						ubi->vid_hdr_aloffset;
727 	}
728 
729 	/* Similar for the data offset */
730 	ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
731 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
732 
733 	dbg_gen("vid_hdr_offset   %d", ubi->vid_hdr_offset);
734 	dbg_gen("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
735 	dbg_gen("vid_hdr_shift    %d", ubi->vid_hdr_shift);
736 	dbg_gen("leb_start        %d", ubi->leb_start);
737 
738 	/* The shift must be aligned to 32-bit boundary */
739 	if (ubi->vid_hdr_shift % 4) {
740 		ubi_err("unaligned VID header shift %d",
741 			ubi->vid_hdr_shift);
742 		return -EINVAL;
743 	}
744 
745 	/* Check sanity */
746 	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
747 	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
748 	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
749 	    ubi->leb_start & (ubi->min_io_size - 1)) {
750 		ubi_err("bad VID header (%d) or data offsets (%d)",
751 			ubi->vid_hdr_offset, ubi->leb_start);
752 		return -EINVAL;
753 	}
754 
755 	/*
756 	 * Set maximum amount of physical erroneous eraseblocks to be 10%.
757 	 * Erroneous PEB are those which have read errors.
758 	 */
759 	ubi->max_erroneous = ubi->peb_count / 10;
760 	if (ubi->max_erroneous < 16)
761 		ubi->max_erroneous = 16;
762 	dbg_gen("max_erroneous    %d", ubi->max_erroneous);
763 
764 	/*
765 	 * It may happen that EC and VID headers are situated in one minimal
766 	 * I/O unit. In this case we can only accept this UBI image in
767 	 * read-only mode.
768 	 */
769 	if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
770 		ubi_warn("EC and VID headers are in the same minimal I/O unit, switch to read-only mode");
771 		ubi->ro_mode = 1;
772 	}
773 
774 	ubi->leb_size = ubi->peb_size - ubi->leb_start;
775 
776 	if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
777 		ubi_msg("MTD device %d is write-protected, attach in read-only mode",
778 			ubi->mtd->index);
779 		ubi->ro_mode = 1;
780 	}
781 
782 	/*
783 	 * Note, ideally, we have to initialize @ubi->bad_peb_count here. But
784 	 * unfortunately, MTD does not provide this information. We should loop
785 	 * over all physical eraseblocks and invoke mtd->block_is_bad() for
786 	 * each physical eraseblock. So, we leave @ubi->bad_peb_count
787 	 * uninitialized so far.
788 	 */
789 
790 	return 0;
791 }
792 
793 /**
794  * autoresize - re-size the volume which has the "auto-resize" flag set.
795  * @ubi: UBI device description object
796  * @vol_id: ID of the volume to re-size
797  *
798  * This function re-sizes the volume marked by the %UBI_VTBL_AUTORESIZE_FLG in
799  * the volume table to the largest possible size. See comments in ubi-header.h
800  * for more description of the flag. Returns zero in case of success and a
801  * negative error code in case of failure.
802  */
803 static int autoresize(struct ubi_device *ubi, int vol_id)
804 {
805 	struct ubi_volume_desc desc;
806 	struct ubi_volume *vol = ubi->volumes[vol_id];
807 	int err, old_reserved_pebs = vol->reserved_pebs;
808 
809 	if (ubi->ro_mode) {
810 		ubi_warn("skip auto-resize because of R/O mode");
811 		return 0;
812 	}
813 
814 	/*
815 	 * Clear the auto-resize flag in the volume in-memory copy of the
816 	 * volume table, and 'ubi_resize_volume()' will propagate this change
817 	 * to the flash.
818 	 */
819 	ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;
820 
821 	if (ubi->avail_pebs == 0) {
822 		struct ubi_vtbl_record vtbl_rec;
823 
824 		/*
825 		 * No available PEBs to re-size the volume, clear the flag on
826 		 * flash and exit.
827 		 */
828 		vtbl_rec = ubi->vtbl[vol_id];
829 		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
830 		if (err)
831 			ubi_err("cannot clean auto-resize flag for volume %d",
832 				vol_id);
833 	} else {
834 		desc.vol = vol;
835 		err = ubi_resize_volume(&desc,
836 					old_reserved_pebs + ubi->avail_pebs);
837 		if (err)
838 			ubi_err("cannot auto-resize volume %d", vol_id);
839 	}
840 
841 	if (err)
842 		return err;
843 
844 	ubi_msg("volume %d (\"%s\") re-sized from %d to %d LEBs", vol_id,
845 		vol->name, old_reserved_pebs, vol->reserved_pebs);
846 	return 0;
847 }
848 
849 /**
850  * ubi_attach_mtd_dev - attach an MTD device.
851  * @mtd: MTD device description object
852  * @ubi_num: number to assign to the new UBI device
853  * @vid_hdr_offset: VID header offset
854  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
855  *
856  * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
857  * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
858  * which case this function finds a vacant device number and assigns it
859  * automatically. Returns the new UBI device number in case of success and a
860  * negative error code in case of failure.
861  *
862  * Note, the invocations of this function has to be serialized by the
863  * @ubi_devices_mutex.
864  */
865 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
866 		       int vid_hdr_offset, int max_beb_per1024)
867 {
868 	struct ubi_device *ubi;
869 	int i, err, ref = 0;
870 
871 	if (max_beb_per1024 < 0 || max_beb_per1024 > MAX_MTD_UBI_BEB_LIMIT)
872 		return -EINVAL;
873 
874 	if (!max_beb_per1024)
875 		max_beb_per1024 = CONFIG_MTD_UBI_BEB_LIMIT;
876 
877 	/*
878 	 * Check if we already have the same MTD device attached.
879 	 *
880 	 * Note, this function assumes that UBI devices creations and deletions
881 	 * are serialized, so it does not take the &ubi_devices_lock.
882 	 */
883 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
884 		ubi = ubi_devices[i];
885 		if (ubi && mtd->index == ubi->mtd->index) {
886 			ubi_err("mtd%d is already attached to ubi%d",
887 				mtd->index, i);
888 			return -EEXIST;
889 		}
890 	}
891 
892 	/*
893 	 * Make sure this MTD device is not emulated on top of an UBI volume
894 	 * already. Well, generally this recursion works fine, but there are
895 	 * different problems like the UBI module takes a reference to itself
896 	 * by attaching (and thus, opening) the emulated MTD device. This
897 	 * results in inability to unload the module. And in general it makes
898 	 * no sense to attach emulated MTD devices, so we prohibit this.
899 	 */
900 	if (mtd->type == MTD_UBIVOLUME) {
901 		ubi_err("refuse attaching mtd%d - it is already emulated on top of UBI",
902 			mtd->index);
903 		return -EINVAL;
904 	}
905 
906 	if (ubi_num == UBI_DEV_NUM_AUTO) {
907 		/* Search for an empty slot in the @ubi_devices array */
908 		for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
909 			if (!ubi_devices[ubi_num])
910 				break;
911 		if (ubi_num == UBI_MAX_DEVICES) {
912 			ubi_err("only %d UBI devices may be created",
913 				UBI_MAX_DEVICES);
914 			return -ENFILE;
915 		}
916 	} else {
917 		if (ubi_num >= UBI_MAX_DEVICES)
918 			return -EINVAL;
919 
920 		/* Make sure ubi_num is not busy */
921 		if (ubi_devices[ubi_num]) {
922 			ubi_err("ubi%d already exists", ubi_num);
923 			return -EEXIST;
924 		}
925 	}
926 
927 	ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
928 	if (!ubi)
929 		return -ENOMEM;
930 
931 	ubi->mtd = mtd;
932 	ubi->ubi_num = ubi_num;
933 	ubi->vid_hdr_offset = vid_hdr_offset;
934 	ubi->autoresize_vol_id = -1;
935 
936 #ifdef CONFIG_MTD_UBI_FASTMAP
937 	ubi->fm_pool.used = ubi->fm_pool.size = 0;
938 	ubi->fm_wl_pool.used = ubi->fm_wl_pool.size = 0;
939 
940 	/*
941 	 * fm_pool.max_size is 5% of the total number of PEBs but it's also
942 	 * between UBI_FM_MAX_POOL_SIZE and UBI_FM_MIN_POOL_SIZE.
943 	 */
944 	ubi->fm_pool.max_size = min(((int)mtd_div_by_eb(ubi->mtd->size,
945 		ubi->mtd) / 100) * 5, UBI_FM_MAX_POOL_SIZE);
946 	if (ubi->fm_pool.max_size < UBI_FM_MIN_POOL_SIZE)
947 		ubi->fm_pool.max_size = UBI_FM_MIN_POOL_SIZE;
948 
949 	ubi->fm_wl_pool.max_size = UBI_FM_WL_POOL_SIZE;
950 	ubi->fm_disabled = !fm_autoconvert;
951 
952 	if (!ubi->fm_disabled && (int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd)
953 	    <= UBI_FM_MAX_START) {
954 		ubi_err("More than %i PEBs are needed for fastmap, sorry.",
955 			UBI_FM_MAX_START);
956 		ubi->fm_disabled = 1;
957 	}
958 
959 	ubi_msg("default fastmap pool size: %d", ubi->fm_pool.max_size);
960 	ubi_msg("default fastmap WL pool size: %d", ubi->fm_wl_pool.max_size);
961 #else
962 	ubi->fm_disabled = 1;
963 #endif
964 	mutex_init(&ubi->buf_mutex);
965 	mutex_init(&ubi->ckvol_mutex);
966 	mutex_init(&ubi->device_mutex);
967 	spin_lock_init(&ubi->volumes_lock);
968 	mutex_init(&ubi->fm_mutex);
969 	init_rwsem(&ubi->fm_sem);
970 
971 	ubi_msg("attaching mtd%d to ubi%d", mtd->index, ubi_num);
972 
973 	err = io_init(ubi, max_beb_per1024);
974 	if (err)
975 		goto out_free;
976 
977 	err = -ENOMEM;
978 	ubi->peb_buf = vmalloc(ubi->peb_size);
979 	if (!ubi->peb_buf)
980 		goto out_free;
981 
982 #ifdef CONFIG_MTD_UBI_FASTMAP
983 	ubi->fm_size = ubi_calc_fm_size(ubi);
984 	ubi->fm_buf = vzalloc(ubi->fm_size);
985 	if (!ubi->fm_buf)
986 		goto out_free;
987 #endif
988 	err = ubi_attach(ubi, 0);
989 	if (err) {
990 		ubi_err("failed to attach mtd%d, error %d", mtd->index, err);
991 		goto out_free;
992 	}
993 
994 	if (ubi->autoresize_vol_id != -1) {
995 		err = autoresize(ubi, ubi->autoresize_vol_id);
996 		if (err)
997 			goto out_detach;
998 	}
999 
1000 	err = uif_init(ubi, &ref);
1001 	if (err)
1002 		goto out_detach;
1003 
1004 	err = ubi_debugfs_init_dev(ubi);
1005 	if (err)
1006 		goto out_uif;
1007 
1008 	ubi->bgt_thread = kthread_create(ubi_thread, ubi, ubi->bgt_name);
1009 	if (IS_ERR(ubi->bgt_thread)) {
1010 		err = PTR_ERR(ubi->bgt_thread);
1011 		ubi_err("cannot spawn \"%s\", error %d", ubi->bgt_name,
1012 			err);
1013 		goto out_debugfs;
1014 	}
1015 
1016 	ubi_msg("attached mtd%d (name \"%s\", size %llu MiB) to ubi%d",
1017 		mtd->index, mtd->name, ubi->flash_size >> 20, ubi_num);
1018 	ubi_msg("PEB size: %d bytes (%d KiB), LEB size: %d bytes",
1019 		ubi->peb_size, ubi->peb_size >> 10, ubi->leb_size);
1020 	ubi_msg("min./max. I/O unit sizes: %d/%d, sub-page size %d",
1021 		ubi->min_io_size, ubi->max_write_size, ubi->hdrs_min_io_size);
1022 	ubi_msg("VID header offset: %d (aligned %d), data offset: %d",
1023 		ubi->vid_hdr_offset, ubi->vid_hdr_aloffset, ubi->leb_start);
1024 	ubi_msg("good PEBs: %d, bad PEBs: %d, corrupted PEBs: %d",
1025 		ubi->good_peb_count, ubi->bad_peb_count, ubi->corr_peb_count);
1026 	ubi_msg("user volume: %d, internal volumes: %d, max. volumes count: %d",
1027 		ubi->vol_count - UBI_INT_VOL_COUNT, UBI_INT_VOL_COUNT,
1028 		ubi->vtbl_slots);
1029 	ubi_msg("max/mean erase counter: %d/%d, WL threshold: %d, image sequence number: %u",
1030 		ubi->max_ec, ubi->mean_ec, CONFIG_MTD_UBI_WL_THRESHOLD,
1031 		ubi->image_seq);
1032 	ubi_msg("available PEBs: %d, total reserved PEBs: %d, PEBs reserved for bad PEB handling: %d",
1033 		ubi->avail_pebs, ubi->rsvd_pebs, ubi->beb_rsvd_pebs);
1034 
1035 	/*
1036 	 * The below lock makes sure we do not race with 'ubi_thread()' which
1037 	 * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
1038 	 */
1039 	spin_lock(&ubi->wl_lock);
1040 	ubi->thread_enabled = 1;
1041 	wake_up_process(ubi->bgt_thread);
1042 	spin_unlock(&ubi->wl_lock);
1043 
1044 	ubi_devices[ubi_num] = ubi;
1045 	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
1046 	return ubi_num;
1047 
1048 out_debugfs:
1049 	ubi_debugfs_exit_dev(ubi);
1050 out_uif:
1051 	get_device(&ubi->dev);
1052 	ubi_assert(ref);
1053 	uif_close(ubi);
1054 out_detach:
1055 	ubi_wl_close(ubi);
1056 	ubi_free_internal_volumes(ubi);
1057 	vfree(ubi->vtbl);
1058 out_free:
1059 	vfree(ubi->peb_buf);
1060 	vfree(ubi->fm_buf);
1061 	if (ref)
1062 		put_device(&ubi->dev);
1063 	else
1064 		kfree(ubi);
1065 	return err;
1066 }
1067 
1068 /**
1069  * ubi_detach_mtd_dev - detach an MTD device.
1070  * @ubi_num: UBI device number to detach from
1071  * @anyway: detach MTD even if device reference count is not zero
1072  *
1073  * This function destroys an UBI device number @ubi_num and detaches the
1074  * underlying MTD device. Returns zero in case of success and %-EBUSY if the
1075  * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
1076  * exist.
1077  *
1078  * Note, the invocations of this function has to be serialized by the
1079  * @ubi_devices_mutex.
1080  */
1081 int ubi_detach_mtd_dev(int ubi_num, int anyway)
1082 {
1083 	struct ubi_device *ubi;
1084 
1085 	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
1086 		return -EINVAL;
1087 
1088 	ubi = ubi_get_device(ubi_num);
1089 	if (!ubi)
1090 		return -EINVAL;
1091 
1092 	spin_lock(&ubi_devices_lock);
1093 	put_device(&ubi->dev);
1094 	ubi->ref_count -= 1;
1095 	if (ubi->ref_count) {
1096 		if (!anyway) {
1097 			spin_unlock(&ubi_devices_lock);
1098 			return -EBUSY;
1099 		}
1100 		/* This may only happen if there is a bug */
1101 		ubi_err("%s reference count %d, destroy anyway",
1102 			ubi->ubi_name, ubi->ref_count);
1103 	}
1104 	ubi_devices[ubi_num] = NULL;
1105 	spin_unlock(&ubi_devices_lock);
1106 
1107 	ubi_assert(ubi_num == ubi->ubi_num);
1108 	ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
1109 	ubi_msg("detaching mtd%d from ubi%d", ubi->mtd->index, ubi_num);
1110 #ifdef CONFIG_MTD_UBI_FASTMAP
1111 	/* If we don't write a new fastmap at detach time we lose all
1112 	 * EC updates that have been made since the last written fastmap. */
1113 	ubi_update_fastmap(ubi);
1114 #endif
1115 	/*
1116 	 * Before freeing anything, we have to stop the background thread to
1117 	 * prevent it from doing anything on this device while we are freeing.
1118 	 */
1119 	if (ubi->bgt_thread)
1120 		kthread_stop(ubi->bgt_thread);
1121 
1122 	/*
1123 	 * Get a reference to the device in order to prevent 'dev_release()'
1124 	 * from freeing the @ubi object.
1125 	 */
1126 	get_device(&ubi->dev);
1127 
1128 	ubi_debugfs_exit_dev(ubi);
1129 	uif_close(ubi);
1130 
1131 	ubi_wl_close(ubi);
1132 	ubi_free_internal_volumes(ubi);
1133 	vfree(ubi->vtbl);
1134 	put_mtd_device(ubi->mtd);
1135 	vfree(ubi->peb_buf);
1136 	vfree(ubi->fm_buf);
1137 	ubi_msg("mtd%d is detached from ubi%d", ubi->mtd->index, ubi->ubi_num);
1138 	put_device(&ubi->dev);
1139 	return 0;
1140 }
1141 
1142 /**
1143  * open_mtd_by_chdev - open an MTD device by its character device node path.
1144  * @mtd_dev: MTD character device node path
1145  *
1146  * This helper function opens an MTD device by its character node device path.
1147  * Returns MTD device description object in case of success and a negative
1148  * error code in case of failure.
1149  */
1150 static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
1151 {
1152 	int err, major, minor, mode;
1153 	struct path path;
1154 
1155 	/* Probably this is an MTD character device node path */
1156 	err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
1157 	if (err)
1158 		return ERR_PTR(err);
1159 
1160 	/* MTD device number is defined by the major / minor numbers */
1161 	major = imajor(path.dentry->d_inode);
1162 	minor = iminor(path.dentry->d_inode);
1163 	mode = path.dentry->d_inode->i_mode;
1164 	path_put(&path);
1165 	if (major != MTD_CHAR_MAJOR || !S_ISCHR(mode))
1166 		return ERR_PTR(-EINVAL);
1167 
1168 	if (minor & 1)
1169 		/*
1170 		 * Just do not think the "/dev/mtdrX" devices support is need,
1171 		 * so do not support them to avoid doing extra work.
1172 		 */
1173 		return ERR_PTR(-EINVAL);
1174 
1175 	return get_mtd_device(NULL, minor / 2);
1176 }
1177 
1178 /**
1179  * open_mtd_device - open MTD device by name, character device path, or number.
1180  * @mtd_dev: name, character device node path, or MTD device device number
1181  *
1182  * This function tries to open and MTD device described by @mtd_dev string,
1183  * which is first treated as ASCII MTD device number, and if it is not true, it
1184  * is treated as MTD device name, and if that is also not true, it is treated
1185  * as MTD character device node path. Returns MTD device description object in
1186  * case of success and a negative error code in case of failure.
1187  */
1188 static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
1189 {
1190 	struct mtd_info *mtd;
1191 	int mtd_num;
1192 	char *endp;
1193 
1194 	mtd_num = simple_strtoul(mtd_dev, &endp, 0);
1195 	if (*endp != '\0' || mtd_dev == endp) {
1196 		/*
1197 		 * This does not look like an ASCII integer, probably this is
1198 		 * MTD device name.
1199 		 */
1200 		mtd = get_mtd_device_nm(mtd_dev);
1201 		if (IS_ERR(mtd) && PTR_ERR(mtd) == -ENODEV)
1202 			/* Probably this is an MTD character device node path */
1203 			mtd = open_mtd_by_chdev(mtd_dev);
1204 	} else
1205 		mtd = get_mtd_device(NULL, mtd_num);
1206 
1207 	return mtd;
1208 }
1209 
1210 static int __init ubi_init(void)
1211 {
1212 	int err, i, k;
1213 
1214 	/* Ensure that EC and VID headers have correct size */
1215 	BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
1216 	BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);
1217 
1218 	if (mtd_devs > UBI_MAX_DEVICES) {
1219 		ubi_err("too many MTD devices, maximum is %d", UBI_MAX_DEVICES);
1220 		return -EINVAL;
1221 	}
1222 
1223 	/* Create base sysfs directory and sysfs files */
1224 	ubi_class = class_create(THIS_MODULE, UBI_NAME_STR);
1225 	if (IS_ERR(ubi_class)) {
1226 		err = PTR_ERR(ubi_class);
1227 		ubi_err("cannot create UBI class");
1228 		goto out;
1229 	}
1230 
1231 	err = class_create_file(ubi_class, &ubi_version);
1232 	if (err) {
1233 		ubi_err("cannot create sysfs file");
1234 		goto out_class;
1235 	}
1236 
1237 	err = misc_register(&ubi_ctrl_cdev);
1238 	if (err) {
1239 		ubi_err("cannot register device");
1240 		goto out_version;
1241 	}
1242 
1243 	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
1244 					      sizeof(struct ubi_wl_entry),
1245 					      0, 0, NULL);
1246 	if (!ubi_wl_entry_slab)
1247 		goto out_dev_unreg;
1248 
1249 	err = ubi_debugfs_init();
1250 	if (err)
1251 		goto out_slab;
1252 
1253 
1254 	/* Attach MTD devices */
1255 	for (i = 0; i < mtd_devs; i++) {
1256 		struct mtd_dev_param *p = &mtd_dev_param[i];
1257 		struct mtd_info *mtd;
1258 
1259 		cond_resched();
1260 
1261 		mtd = open_mtd_device(p->name);
1262 		if (IS_ERR(mtd)) {
1263 			err = PTR_ERR(mtd);
1264 			goto out_detach;
1265 		}
1266 
1267 		mutex_lock(&ubi_devices_mutex);
1268 		err = ubi_attach_mtd_dev(mtd, UBI_DEV_NUM_AUTO,
1269 					 p->vid_hdr_offs, p->max_beb_per1024);
1270 		mutex_unlock(&ubi_devices_mutex);
1271 		if (err < 0) {
1272 			ubi_err("cannot attach mtd%d", mtd->index);
1273 			put_mtd_device(mtd);
1274 
1275 			/*
1276 			 * Originally UBI stopped initializing on any error.
1277 			 * However, later on it was found out that this
1278 			 * behavior is not very good when UBI is compiled into
1279 			 * the kernel and the MTD devices to attach are passed
1280 			 * through the command line. Indeed, UBI failure
1281 			 * stopped whole boot sequence.
1282 			 *
1283 			 * To fix this, we changed the behavior for the
1284 			 * non-module case, but preserved the old behavior for
1285 			 * the module case, just for compatibility. This is a
1286 			 * little inconsistent, though.
1287 			 */
1288 			if (ubi_is_module())
1289 				goto out_detach;
1290 		}
1291 	}
1292 
1293 	return 0;
1294 
1295 out_detach:
1296 	for (k = 0; k < i; k++)
1297 		if (ubi_devices[k]) {
1298 			mutex_lock(&ubi_devices_mutex);
1299 			ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
1300 			mutex_unlock(&ubi_devices_mutex);
1301 		}
1302 	ubi_debugfs_exit();
1303 out_slab:
1304 	kmem_cache_destroy(ubi_wl_entry_slab);
1305 out_dev_unreg:
1306 	misc_deregister(&ubi_ctrl_cdev);
1307 out_version:
1308 	class_remove_file(ubi_class, &ubi_version);
1309 out_class:
1310 	class_destroy(ubi_class);
1311 out:
1312 	ubi_err("UBI error: cannot initialize UBI, error %d", err);
1313 	return err;
1314 }
1315 late_initcall(ubi_init);
1316 
1317 static void __exit ubi_exit(void)
1318 {
1319 	int i;
1320 
1321 	for (i = 0; i < UBI_MAX_DEVICES; i++)
1322 		if (ubi_devices[i]) {
1323 			mutex_lock(&ubi_devices_mutex);
1324 			ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
1325 			mutex_unlock(&ubi_devices_mutex);
1326 		}
1327 	ubi_debugfs_exit();
1328 	kmem_cache_destroy(ubi_wl_entry_slab);
1329 	misc_deregister(&ubi_ctrl_cdev);
1330 	class_remove_file(ubi_class, &ubi_version);
1331 	class_destroy(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 		ubi_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 		ubi_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];
1387 
1388 	if (!val)
1389 		return -EINVAL;
1390 
1391 	if (mtd_devs == UBI_MAX_DEVICES) {
1392 		ubi_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 		ubi_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 		ubi_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 	if (tokens[1])
1427 		p->vid_hdr_offs = bytes_str_to_int(tokens[1]);
1428 
1429 	if (p->vid_hdr_offs < 0)
1430 		return p->vid_hdr_offs;
1431 
1432 	if (tokens[2]) {
1433 		int err = kstrtoint(tokens[2], 10, &p->max_beb_per1024);
1434 
1435 		if (err) {
1436 			ubi_err("UBI error: bad value for max_beb_per1024 parameter: %s",
1437 				tokens[2]);
1438 			return -EINVAL;
1439 		}
1440 	}
1441 
1442 	mtd_devs += 1;
1443 	return 0;
1444 }
1445 
1446 module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 000);
1447 MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024]].\n"
1448 		      "Multiple \"mtd\" parameters may be specified.\n"
1449 		      "MTD devices may be specified by their number, name, or path to the MTD character device node.\n"
1450 		      "Optional \"vid_hdr_offs\" parameter specifies UBI VID header position to be used by UBI. (default value if 0)\n"
1451 		      "Optional \"max_beb_per1024\" parameter specifies the maximum expected bad eraseblock per 1024 eraseblocks. (default value ("
1452 		      __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0)\n"
1453 		      "\n"
1454 		      "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
1455 		      "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"
1456 		      "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"
1457 		      "\t(e.g. if the NAND *chipset* has 4096 PEB, 100 will be reserved for this UBI device).");
1458 #ifdef CONFIG_MTD_UBI_FASTMAP
1459 module_param(fm_autoconvert, bool, 0644);
1460 MODULE_PARM_DESC(fm_autoconvert, "Set this parameter to enable fastmap automatically on images without a fastmap.");
1461 #endif
1462 MODULE_VERSION(__stringify(UBI_VERSION));
1463 MODULE_DESCRIPTION("UBI - Unsorted Block Images");
1464 MODULE_AUTHOR("Artem Bityutskiy");
1465 MODULE_LICENSE("GPL");
1466