xref: /openbmc/linux/drivers/mtd/ubi/build.c (revision 3213486f)
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 mtd_devs;
78 
79 /* MTD devices specification parameters */
80 static struct mtd_dev_param 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 /* UBI version attribute ('/<sysfs>/class/ubi/version') */
108 static ssize_t version_show(struct class *class, struct class_attribute *attr,
109 			    char *buf)
110 {
111 	return sprintf(buf, "%d\n", UBI_VERSION);
112 }
113 static CLASS_ATTR_RO(version);
114 
115 static struct attribute *ubi_class_attrs[] = {
116 	&class_attr_version.attr,
117 	NULL,
118 };
119 ATTRIBUTE_GROUPS(ubi_class);
120 
121 /* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
122 struct class ubi_class = {
123 	.name		= UBI_NAME_STR,
124 	.owner		= THIS_MODULE,
125 	.class_groups	= ubi_class_groups,
126 };
127 
128 static ssize_t dev_attribute_show(struct device *dev,
129 				  struct device_attribute *attr, char *buf);
130 
131 /* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
132 static struct device_attribute dev_eraseblock_size =
133 	__ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
134 static struct device_attribute dev_avail_eraseblocks =
135 	__ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
136 static struct device_attribute dev_total_eraseblocks =
137 	__ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
138 static struct device_attribute dev_volumes_count =
139 	__ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
140 static struct device_attribute dev_max_ec =
141 	__ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
142 static struct device_attribute dev_reserved_for_bad =
143 	__ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
144 static struct device_attribute dev_bad_peb_count =
145 	__ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
146 static struct device_attribute dev_max_vol_count =
147 	__ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
148 static struct device_attribute dev_min_io_size =
149 	__ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
150 static struct device_attribute dev_bgt_enabled =
151 	__ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);
152 static struct device_attribute dev_mtd_num =
153 	__ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
154 static struct device_attribute dev_ro_mode =
155 	__ATTR(ro_mode, S_IRUGO, dev_attribute_show, NULL);
156 
157 /**
158  * ubi_volume_notify - send a volume change notification.
159  * @ubi: UBI device description object
160  * @vol: volume description object of the changed volume
161  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
162  *
163  * This is a helper function which notifies all subscribers about a volume
164  * change event (creation, removal, re-sizing, re-naming, updating). Returns
165  * zero in case of success and a negative error code in case of failure.
166  */
167 int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
168 {
169 	int ret;
170 	struct ubi_notification nt;
171 
172 	ubi_do_get_device_info(ubi, &nt.di);
173 	ubi_do_get_volume_info(ubi, vol, &nt.vi);
174 
175 	switch (ntype) {
176 	case UBI_VOLUME_ADDED:
177 	case UBI_VOLUME_REMOVED:
178 	case UBI_VOLUME_RESIZED:
179 	case UBI_VOLUME_RENAMED:
180 		ret = ubi_update_fastmap(ubi);
181 		if (ret)
182 			ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
183 	}
184 
185 	return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
186 }
187 
188 /**
189  * ubi_notify_all - send a notification to all volumes.
190  * @ubi: UBI device description object
191  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
192  * @nb: the notifier to call
193  *
194  * This function walks all volumes of UBI device @ubi and sends the @ntype
195  * notification for each volume. If @nb is %NULL, then all registered notifiers
196  * are called, otherwise only the @nb notifier is called. Returns the number of
197  * sent notifications.
198  */
199 int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
200 {
201 	struct ubi_notification nt;
202 	int i, count = 0;
203 
204 	ubi_do_get_device_info(ubi, &nt.di);
205 
206 	mutex_lock(&ubi->device_mutex);
207 	for (i = 0; i < ubi->vtbl_slots; i++) {
208 		/*
209 		 * Since the @ubi->device is locked, and we are not going to
210 		 * change @ubi->volumes, we do not have to lock
211 		 * @ubi->volumes_lock.
212 		 */
213 		if (!ubi->volumes[i])
214 			continue;
215 
216 		ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
217 		if (nb)
218 			nb->notifier_call(nb, ntype, &nt);
219 		else
220 			blocking_notifier_call_chain(&ubi_notifiers, ntype,
221 						     &nt);
222 		count += 1;
223 	}
224 	mutex_unlock(&ubi->device_mutex);
225 
226 	return count;
227 }
228 
229 /**
230  * ubi_enumerate_volumes - send "add" notification for all existing volumes.
231  * @nb: the notifier to call
232  *
233  * This function walks all UBI devices and volumes and sends the
234  * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
235  * registered notifiers are called, otherwise only the @nb notifier is called.
236  * Returns the number of sent notifications.
237  */
238 int ubi_enumerate_volumes(struct notifier_block *nb)
239 {
240 	int i, count = 0;
241 
242 	/*
243 	 * Since the @ubi_devices_mutex is locked, and we are not going to
244 	 * change @ubi_devices, we do not have to lock @ubi_devices_lock.
245 	 */
246 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
247 		struct ubi_device *ubi = ubi_devices[i];
248 
249 		if (!ubi)
250 			continue;
251 		count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
252 	}
253 
254 	return count;
255 }
256 
257 /**
258  * ubi_get_device - get UBI device.
259  * @ubi_num: UBI device number
260  *
261  * This function returns UBI device description object for UBI device number
262  * @ubi_num, or %NULL if the device does not exist. This function increases the
263  * device reference count to prevent removal of the device. In other words, the
264  * device cannot be removed if its reference count is not zero.
265  */
266 struct ubi_device *ubi_get_device(int ubi_num)
267 {
268 	struct ubi_device *ubi;
269 
270 	spin_lock(&ubi_devices_lock);
271 	ubi = ubi_devices[ubi_num];
272 	if (ubi) {
273 		ubi_assert(ubi->ref_count >= 0);
274 		ubi->ref_count += 1;
275 		get_device(&ubi->dev);
276 	}
277 	spin_unlock(&ubi_devices_lock);
278 
279 	return ubi;
280 }
281 
282 /**
283  * ubi_put_device - drop an UBI device reference.
284  * @ubi: UBI device description object
285  */
286 void ubi_put_device(struct ubi_device *ubi)
287 {
288 	spin_lock(&ubi_devices_lock);
289 	ubi->ref_count -= 1;
290 	put_device(&ubi->dev);
291 	spin_unlock(&ubi_devices_lock);
292 }
293 
294 /**
295  * ubi_get_by_major - get UBI device by character device major number.
296  * @major: major number
297  *
298  * This function is similar to 'ubi_get_device()', but it searches the device
299  * by its major number.
300  */
301 struct ubi_device *ubi_get_by_major(int major)
302 {
303 	int i;
304 	struct ubi_device *ubi;
305 
306 	spin_lock(&ubi_devices_lock);
307 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
308 		ubi = ubi_devices[i];
309 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
310 			ubi_assert(ubi->ref_count >= 0);
311 			ubi->ref_count += 1;
312 			get_device(&ubi->dev);
313 			spin_unlock(&ubi_devices_lock);
314 			return ubi;
315 		}
316 	}
317 	spin_unlock(&ubi_devices_lock);
318 
319 	return NULL;
320 }
321 
322 /**
323  * ubi_major2num - get UBI device number by character device major number.
324  * @major: major number
325  *
326  * This function searches UBI device number object by its major number. If UBI
327  * device was not found, this function returns -ENODEV, otherwise the UBI device
328  * number is returned.
329  */
330 int ubi_major2num(int major)
331 {
332 	int i, ubi_num = -ENODEV;
333 
334 	spin_lock(&ubi_devices_lock);
335 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
336 		struct ubi_device *ubi = ubi_devices[i];
337 
338 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
339 			ubi_num = ubi->ubi_num;
340 			break;
341 		}
342 	}
343 	spin_unlock(&ubi_devices_lock);
344 
345 	return ubi_num;
346 }
347 
348 /* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
349 static ssize_t dev_attribute_show(struct device *dev,
350 				  struct device_attribute *attr, char *buf)
351 {
352 	ssize_t ret;
353 	struct ubi_device *ubi;
354 
355 	/*
356 	 * The below code looks weird, but it actually makes sense. We get the
357 	 * UBI device reference from the contained 'struct ubi_device'. But it
358 	 * is unclear if the device was removed or not yet. Indeed, if the
359 	 * device was removed before we increased its reference count,
360 	 * 'ubi_get_device()' will return -ENODEV and we fail.
361 	 *
362 	 * Remember, 'struct ubi_device' is freed in the release function, so
363 	 * we still can use 'ubi->ubi_num'.
364 	 */
365 	ubi = container_of(dev, struct ubi_device, dev);
366 	ubi = ubi_get_device(ubi->ubi_num);
367 	if (!ubi)
368 		return -ENODEV;
369 
370 	if (attr == &dev_eraseblock_size)
371 		ret = sprintf(buf, "%d\n", ubi->leb_size);
372 	else if (attr == &dev_avail_eraseblocks)
373 		ret = sprintf(buf, "%d\n", ubi->avail_pebs);
374 	else if (attr == &dev_total_eraseblocks)
375 		ret = sprintf(buf, "%d\n", ubi->good_peb_count);
376 	else if (attr == &dev_volumes_count)
377 		ret = sprintf(buf, "%d\n", ubi->vol_count - UBI_INT_VOL_COUNT);
378 	else if (attr == &dev_max_ec)
379 		ret = sprintf(buf, "%d\n", ubi->max_ec);
380 	else if (attr == &dev_reserved_for_bad)
381 		ret = sprintf(buf, "%d\n", ubi->beb_rsvd_pebs);
382 	else if (attr == &dev_bad_peb_count)
383 		ret = sprintf(buf, "%d\n", ubi->bad_peb_count);
384 	else if (attr == &dev_max_vol_count)
385 		ret = sprintf(buf, "%d\n", ubi->vtbl_slots);
386 	else if (attr == &dev_min_io_size)
387 		ret = sprintf(buf, "%d\n", ubi->min_io_size);
388 	else if (attr == &dev_bgt_enabled)
389 		ret = sprintf(buf, "%d\n", ubi->thread_enabled);
390 	else if (attr == &dev_mtd_num)
391 		ret = sprintf(buf, "%d\n", ubi->mtd->index);
392 	else if (attr == &dev_ro_mode)
393 		ret = sprintf(buf, "%d\n", ubi->ro_mode);
394 	else
395 		ret = -EINVAL;
396 
397 	ubi_put_device(ubi);
398 	return ret;
399 }
400 
401 static struct attribute *ubi_dev_attrs[] = {
402 	&dev_eraseblock_size.attr,
403 	&dev_avail_eraseblocks.attr,
404 	&dev_total_eraseblocks.attr,
405 	&dev_volumes_count.attr,
406 	&dev_max_ec.attr,
407 	&dev_reserved_for_bad.attr,
408 	&dev_bad_peb_count.attr,
409 	&dev_max_vol_count.attr,
410 	&dev_min_io_size.attr,
411 	&dev_bgt_enabled.attr,
412 	&dev_mtd_num.attr,
413 	&dev_ro_mode.attr,
414 	NULL
415 };
416 ATTRIBUTE_GROUPS(ubi_dev);
417 
418 static void dev_release(struct device *dev)
419 {
420 	struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);
421 
422 	kfree(ubi);
423 }
424 
425 /**
426  * kill_volumes - destroy all user volumes.
427  * @ubi: UBI device description object
428  */
429 static void kill_volumes(struct ubi_device *ubi)
430 {
431 	int i;
432 
433 	for (i = 0; i < ubi->vtbl_slots; i++)
434 		if (ubi->volumes[i])
435 			ubi_free_volume(ubi, ubi->volumes[i]);
436 }
437 
438 /**
439  * uif_init - initialize user interfaces for an UBI device.
440  * @ubi: UBI device description object
441  *
442  * This function initializes various user interfaces for an UBI device. If the
443  * initialization fails at an early stage, this function frees all the
444  * resources it allocated, returns an error.
445  *
446  * This function returns zero in case of success and a negative error code in
447  * case of failure.
448  */
449 static int uif_init(struct ubi_device *ubi)
450 {
451 	int i, err;
452 	dev_t dev;
453 
454 	sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);
455 
456 	/*
457 	 * Major numbers for the UBI character devices are allocated
458 	 * dynamically. Major numbers of volume character devices are
459 	 * equivalent to ones of the corresponding UBI character device. Minor
460 	 * numbers of UBI character devices are 0, while minor numbers of
461 	 * volume character devices start from 1. Thus, we allocate one major
462 	 * number and ubi->vtbl_slots + 1 minor numbers.
463 	 */
464 	err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
465 	if (err) {
466 		ubi_err(ubi, "cannot register UBI character devices");
467 		return err;
468 	}
469 
470 	ubi->dev.devt = dev;
471 
472 	ubi_assert(MINOR(dev) == 0);
473 	cdev_init(&ubi->cdev, &ubi_cdev_operations);
474 	dbg_gen("%s major is %u", ubi->ubi_name, MAJOR(dev));
475 	ubi->cdev.owner = THIS_MODULE;
476 
477 	dev_set_name(&ubi->dev, UBI_NAME_STR "%d", ubi->ubi_num);
478 	err = cdev_device_add(&ubi->cdev, &ubi->dev);
479 	if (err)
480 		goto out_unreg;
481 
482 	for (i = 0; i < ubi->vtbl_slots; i++)
483 		if (ubi->volumes[i]) {
484 			err = ubi_add_volume(ubi, ubi->volumes[i]);
485 			if (err) {
486 				ubi_err(ubi, "cannot add volume %d", i);
487 				goto out_volumes;
488 			}
489 		}
490 
491 	return 0;
492 
493 out_volumes:
494 	kill_volumes(ubi);
495 	cdev_device_del(&ubi->cdev, &ubi->dev);
496 out_unreg:
497 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
498 	ubi_err(ubi, "cannot initialize UBI %s, error %d",
499 		ubi->ubi_name, err);
500 	return err;
501 }
502 
503 /**
504  * uif_close - close user interfaces for an UBI device.
505  * @ubi: UBI device description object
506  *
507  * Note, since this function un-registers UBI volume device objects (@vol->dev),
508  * the memory allocated voe the volumes is freed as well (in the release
509  * function).
510  */
511 static void uif_close(struct ubi_device *ubi)
512 {
513 	kill_volumes(ubi);
514 	cdev_device_del(&ubi->cdev, &ubi->dev);
515 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
516 }
517 
518 /**
519  * ubi_free_internal_volumes - free internal volumes.
520  * @ubi: UBI device description object
521  */
522 void ubi_free_internal_volumes(struct ubi_device *ubi)
523 {
524 	int i;
525 
526 	for (i = ubi->vtbl_slots;
527 	     i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
528 		ubi_eba_replace_table(ubi->volumes[i], NULL);
529 		ubi_fastmap_destroy_checkmap(ubi->volumes[i]);
530 		kfree(ubi->volumes[i]);
531 	}
532 }
533 
534 static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
535 {
536 	int limit, device_pebs;
537 	uint64_t device_size;
538 
539 	if (!max_beb_per1024) {
540 		/*
541 		 * Since max_beb_per1024 has not been set by the user in either
542 		 * the cmdline or Kconfig, use mtd_max_bad_blocks to set the
543 		 * limit if it is supported by the device.
544 		 */
545 		limit = mtd_max_bad_blocks(ubi->mtd, 0, ubi->mtd->size);
546 		if (limit < 0)
547 			return 0;
548 		return limit;
549 	}
550 
551 	/*
552 	 * Here we are using size of the entire flash chip and
553 	 * not just the MTD partition size because the maximum
554 	 * number of bad eraseblocks is a percentage of the
555 	 * whole device and bad eraseblocks are not fairly
556 	 * distributed over the flash chip. So the worst case
557 	 * is that all the bad eraseblocks of the chip are in
558 	 * the MTD partition we are attaching (ubi->mtd).
559 	 */
560 	device_size = mtd_get_device_size(ubi->mtd);
561 	device_pebs = mtd_div_by_eb(device_size, ubi->mtd);
562 	limit = mult_frac(device_pebs, max_beb_per1024, 1024);
563 
564 	/* Round it up */
565 	if (mult_frac(limit, 1024, max_beb_per1024) < device_pebs)
566 		limit += 1;
567 
568 	return limit;
569 }
570 
571 /**
572  * io_init - initialize I/O sub-system for a given UBI device.
573  * @ubi: UBI device description object
574  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
575  *
576  * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
577  * assumed:
578  *   o EC header is always at offset zero - this cannot be changed;
579  *   o VID header starts just after the EC header at the closest address
580  *     aligned to @io->hdrs_min_io_size;
581  *   o data starts just after the VID header at the closest address aligned to
582  *     @io->min_io_size
583  *
584  * This function returns zero in case of success and a negative error code in
585  * case of failure.
586  */
587 static int io_init(struct ubi_device *ubi, int max_beb_per1024)
588 {
589 	dbg_gen("sizeof(struct ubi_ainf_peb) %zu", sizeof(struct ubi_ainf_peb));
590 	dbg_gen("sizeof(struct ubi_wl_entry) %zu", sizeof(struct ubi_wl_entry));
591 
592 	if (ubi->mtd->numeraseregions != 0) {
593 		/*
594 		 * Some flashes have several erase regions. Different regions
595 		 * may have different eraseblock size and other
596 		 * characteristics. It looks like mostly multi-region flashes
597 		 * have one "main" region and one or more small regions to
598 		 * store boot loader code or boot parameters or whatever. I
599 		 * guess we should just pick the largest region. But this is
600 		 * not implemented.
601 		 */
602 		ubi_err(ubi, "multiple regions, not implemented");
603 		return -EINVAL;
604 	}
605 
606 	if (ubi->vid_hdr_offset < 0)
607 		return -EINVAL;
608 
609 	/*
610 	 * Note, in this implementation we support MTD devices with 0x7FFFFFFF
611 	 * physical eraseblocks maximum.
612 	 */
613 
614 	ubi->peb_size   = ubi->mtd->erasesize;
615 	ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
616 	ubi->flash_size = ubi->mtd->size;
617 
618 	if (mtd_can_have_bb(ubi->mtd)) {
619 		ubi->bad_allowed = 1;
620 		ubi->bad_peb_limit = get_bad_peb_limit(ubi, max_beb_per1024);
621 	}
622 
623 	if (ubi->mtd->type == MTD_NORFLASH) {
624 		ubi_assert(ubi->mtd->writesize == 1);
625 		ubi->nor_flash = 1;
626 	}
627 
628 	ubi->min_io_size = ubi->mtd->writesize;
629 	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
630 
631 	/*
632 	 * Make sure minimal I/O unit is power of 2. Note, there is no
633 	 * fundamental reason for this assumption. It is just an optimization
634 	 * which allows us to avoid costly division operations.
635 	 */
636 	if (!is_power_of_2(ubi->min_io_size)) {
637 		ubi_err(ubi, "min. I/O unit (%d) is not power of 2",
638 			ubi->min_io_size);
639 		return -EINVAL;
640 	}
641 
642 	ubi_assert(ubi->hdrs_min_io_size > 0);
643 	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
644 	ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
645 
646 	ubi->max_write_size = ubi->mtd->writebufsize;
647 	/*
648 	 * Maximum write size has to be greater or equivalent to min. I/O
649 	 * size, and be multiple of min. I/O size.
650 	 */
651 	if (ubi->max_write_size < ubi->min_io_size ||
652 	    ubi->max_write_size % ubi->min_io_size ||
653 	    !is_power_of_2(ubi->max_write_size)) {
654 		ubi_err(ubi, "bad write buffer size %d for %d min. I/O unit",
655 			ubi->max_write_size, ubi->min_io_size);
656 		return -EINVAL;
657 	}
658 
659 	/* Calculate default aligned sizes of EC and VID headers */
660 	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
661 	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
662 
663 	dbg_gen("min_io_size      %d", ubi->min_io_size);
664 	dbg_gen("max_write_size   %d", ubi->max_write_size);
665 	dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
666 	dbg_gen("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
667 	dbg_gen("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
668 
669 	if (ubi->vid_hdr_offset == 0)
670 		/* Default offset */
671 		ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
672 				      ubi->ec_hdr_alsize;
673 	else {
674 		ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
675 						~(ubi->hdrs_min_io_size - 1);
676 		ubi->vid_hdr_shift = ubi->vid_hdr_offset -
677 						ubi->vid_hdr_aloffset;
678 	}
679 
680 	/* Similar for the data offset */
681 	ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
682 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
683 
684 	dbg_gen("vid_hdr_offset   %d", ubi->vid_hdr_offset);
685 	dbg_gen("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
686 	dbg_gen("vid_hdr_shift    %d", ubi->vid_hdr_shift);
687 	dbg_gen("leb_start        %d", ubi->leb_start);
688 
689 	/* The shift must be aligned to 32-bit boundary */
690 	if (ubi->vid_hdr_shift % 4) {
691 		ubi_err(ubi, "unaligned VID header shift %d",
692 			ubi->vid_hdr_shift);
693 		return -EINVAL;
694 	}
695 
696 	/* Check sanity */
697 	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
698 	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
699 	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
700 	    ubi->leb_start & (ubi->min_io_size - 1)) {
701 		ubi_err(ubi, "bad VID header (%d) or data offsets (%d)",
702 			ubi->vid_hdr_offset, ubi->leb_start);
703 		return -EINVAL;
704 	}
705 
706 	/*
707 	 * Set maximum amount of physical erroneous eraseblocks to be 10%.
708 	 * Erroneous PEB are those which have read errors.
709 	 */
710 	ubi->max_erroneous = ubi->peb_count / 10;
711 	if (ubi->max_erroneous < 16)
712 		ubi->max_erroneous = 16;
713 	dbg_gen("max_erroneous    %d", ubi->max_erroneous);
714 
715 	/*
716 	 * It may happen that EC and VID headers are situated in one minimal
717 	 * I/O unit. In this case we can only accept this UBI image in
718 	 * read-only mode.
719 	 */
720 	if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
721 		ubi_warn(ubi, "EC and VID headers are in the same minimal I/O unit, switch to read-only mode");
722 		ubi->ro_mode = 1;
723 	}
724 
725 	ubi->leb_size = ubi->peb_size - ubi->leb_start;
726 
727 	if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
728 		ubi_msg(ubi, "MTD device %d is write-protected, attach in read-only mode",
729 			ubi->mtd->index);
730 		ubi->ro_mode = 1;
731 	}
732 
733 	/*
734 	 * Note, ideally, we have to initialize @ubi->bad_peb_count here. But
735 	 * unfortunately, MTD does not provide this information. We should loop
736 	 * over all physical eraseblocks and invoke mtd->block_is_bad() for
737 	 * each physical eraseblock. So, we leave @ubi->bad_peb_count
738 	 * uninitialized so far.
739 	 */
740 
741 	return 0;
742 }
743 
744 /**
745  * autoresize - re-size the volume which has the "auto-resize" flag set.
746  * @ubi: UBI device description object
747  * @vol_id: ID of the volume to re-size
748  *
749  * This function re-sizes the volume marked by the %UBI_VTBL_AUTORESIZE_FLG in
750  * the volume table to the largest possible size. See comments in ubi-header.h
751  * for more description of the flag. Returns zero in case of success and a
752  * negative error code in case of failure.
753  */
754 static int autoresize(struct ubi_device *ubi, int vol_id)
755 {
756 	struct ubi_volume_desc desc;
757 	struct ubi_volume *vol = ubi->volumes[vol_id];
758 	int err, old_reserved_pebs = vol->reserved_pebs;
759 
760 	if (ubi->ro_mode) {
761 		ubi_warn(ubi, "skip auto-resize because of R/O mode");
762 		return 0;
763 	}
764 
765 	/*
766 	 * Clear the auto-resize flag in the volume in-memory copy of the
767 	 * volume table, and 'ubi_resize_volume()' will propagate this change
768 	 * to the flash.
769 	 */
770 	ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;
771 
772 	if (ubi->avail_pebs == 0) {
773 		struct ubi_vtbl_record vtbl_rec;
774 
775 		/*
776 		 * No available PEBs to re-size the volume, clear the flag on
777 		 * flash and exit.
778 		 */
779 		vtbl_rec = ubi->vtbl[vol_id];
780 		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
781 		if (err)
782 			ubi_err(ubi, "cannot clean auto-resize flag for volume %d",
783 				vol_id);
784 	} else {
785 		desc.vol = vol;
786 		err = ubi_resize_volume(&desc,
787 					old_reserved_pebs + ubi->avail_pebs);
788 		if (err)
789 			ubi_err(ubi, "cannot auto-resize volume %d",
790 				vol_id);
791 	}
792 
793 	if (err)
794 		return err;
795 
796 	ubi_msg(ubi, "volume %d (\"%s\") re-sized from %d to %d LEBs",
797 		vol_id, vol->name, old_reserved_pebs, vol->reserved_pebs);
798 	return 0;
799 }
800 
801 /**
802  * ubi_attach_mtd_dev - attach an MTD device.
803  * @mtd: MTD device description object
804  * @ubi_num: number to assign to the new UBI device
805  * @vid_hdr_offset: VID header offset
806  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
807  *
808  * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
809  * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
810  * which case this function finds a vacant device number and assigns it
811  * automatically. Returns the new UBI device number in case of success and a
812  * negative error code in case of failure.
813  *
814  * Note, the invocations of this function has to be serialized by the
815  * @ubi_devices_mutex.
816  */
817 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
818 		       int vid_hdr_offset, int max_beb_per1024)
819 {
820 	struct ubi_device *ubi;
821 	int i, err;
822 
823 	if (max_beb_per1024 < 0 || max_beb_per1024 > MAX_MTD_UBI_BEB_LIMIT)
824 		return -EINVAL;
825 
826 	if (!max_beb_per1024)
827 		max_beb_per1024 = CONFIG_MTD_UBI_BEB_LIMIT;
828 
829 	/*
830 	 * Check if we already have the same MTD device attached.
831 	 *
832 	 * Note, this function assumes that UBI devices creations and deletions
833 	 * are serialized, so it does not take the &ubi_devices_lock.
834 	 */
835 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
836 		ubi = ubi_devices[i];
837 		if (ubi && mtd->index == ubi->mtd->index) {
838 			pr_err("ubi: mtd%d is already attached to ubi%d\n",
839 				mtd->index, i);
840 			return -EEXIST;
841 		}
842 	}
843 
844 	/*
845 	 * Make sure this MTD device is not emulated on top of an UBI volume
846 	 * already. Well, generally this recursion works fine, but there are
847 	 * different problems like the UBI module takes a reference to itself
848 	 * by attaching (and thus, opening) the emulated MTD device. This
849 	 * results in inability to unload the module. And in general it makes
850 	 * no sense to attach emulated MTD devices, so we prohibit this.
851 	 */
852 	if (mtd->type == MTD_UBIVOLUME) {
853 		pr_err("ubi: refuse attaching mtd%d - it is already emulated on top of UBI\n",
854 			mtd->index);
855 		return -EINVAL;
856 	}
857 
858 	/*
859 	 * Both UBI and UBIFS have been designed for SLC NAND and NOR flashes.
860 	 * MLC NAND is different and needs special care, otherwise UBI or UBIFS
861 	 * will die soon and you will lose all your data.
862 	 */
863 	if (mtd->type == MTD_MLCNANDFLASH) {
864 		pr_err("ubi: refuse attaching mtd%d - MLC NAND is not supported\n",
865 			mtd->index);
866 		return -EINVAL;
867 	}
868 
869 	if (ubi_num == UBI_DEV_NUM_AUTO) {
870 		/* Search for an empty slot in the @ubi_devices array */
871 		for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
872 			if (!ubi_devices[ubi_num])
873 				break;
874 		if (ubi_num == UBI_MAX_DEVICES) {
875 			pr_err("ubi: only %d UBI devices may be created\n",
876 				UBI_MAX_DEVICES);
877 			return -ENFILE;
878 		}
879 	} else {
880 		if (ubi_num >= UBI_MAX_DEVICES)
881 			return -EINVAL;
882 
883 		/* Make sure ubi_num is not busy */
884 		if (ubi_devices[ubi_num]) {
885 			pr_err("ubi: ubi%i already exists\n", ubi_num);
886 			return -EEXIST;
887 		}
888 	}
889 
890 	ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
891 	if (!ubi)
892 		return -ENOMEM;
893 
894 	device_initialize(&ubi->dev);
895 	ubi->dev.release = dev_release;
896 	ubi->dev.class = &ubi_class;
897 	ubi->dev.groups = ubi_dev_groups;
898 
899 	ubi->mtd = mtd;
900 	ubi->ubi_num = ubi_num;
901 	ubi->vid_hdr_offset = vid_hdr_offset;
902 	ubi->autoresize_vol_id = -1;
903 
904 #ifdef CONFIG_MTD_UBI_FASTMAP
905 	ubi->fm_pool.used = ubi->fm_pool.size = 0;
906 	ubi->fm_wl_pool.used = ubi->fm_wl_pool.size = 0;
907 
908 	/*
909 	 * fm_pool.max_size is 5% of the total number of PEBs but it's also
910 	 * between UBI_FM_MAX_POOL_SIZE and UBI_FM_MIN_POOL_SIZE.
911 	 */
912 	ubi->fm_pool.max_size = min(((int)mtd_div_by_eb(ubi->mtd->size,
913 		ubi->mtd) / 100) * 5, UBI_FM_MAX_POOL_SIZE);
914 	ubi->fm_pool.max_size = max(ubi->fm_pool.max_size,
915 		UBI_FM_MIN_POOL_SIZE);
916 
917 	ubi->fm_wl_pool.max_size = ubi->fm_pool.max_size / 2;
918 	ubi->fm_disabled = !fm_autoconvert;
919 	if (fm_debug)
920 		ubi_enable_dbg_chk_fastmap(ubi);
921 
922 	if (!ubi->fm_disabled && (int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd)
923 	    <= UBI_FM_MAX_START) {
924 		ubi_err(ubi, "More than %i PEBs are needed for fastmap, sorry.",
925 			UBI_FM_MAX_START);
926 		ubi->fm_disabled = 1;
927 	}
928 
929 	ubi_msg(ubi, "default fastmap pool size: %d", ubi->fm_pool.max_size);
930 	ubi_msg(ubi, "default fastmap WL pool size: %d",
931 		ubi->fm_wl_pool.max_size);
932 #else
933 	ubi->fm_disabled = 1;
934 #endif
935 	mutex_init(&ubi->buf_mutex);
936 	mutex_init(&ubi->ckvol_mutex);
937 	mutex_init(&ubi->device_mutex);
938 	spin_lock_init(&ubi->volumes_lock);
939 	init_rwsem(&ubi->fm_protect);
940 	init_rwsem(&ubi->fm_eba_sem);
941 
942 	ubi_msg(ubi, "attaching mtd%d", mtd->index);
943 
944 	err = io_init(ubi, max_beb_per1024);
945 	if (err)
946 		goto out_free;
947 
948 	err = -ENOMEM;
949 	ubi->peb_buf = vmalloc(ubi->peb_size);
950 	if (!ubi->peb_buf)
951 		goto out_free;
952 
953 #ifdef CONFIG_MTD_UBI_FASTMAP
954 	ubi->fm_size = ubi_calc_fm_size(ubi);
955 	ubi->fm_buf = vzalloc(ubi->fm_size);
956 	if (!ubi->fm_buf)
957 		goto out_free;
958 #endif
959 	err = ubi_attach(ubi, 0);
960 	if (err) {
961 		ubi_err(ubi, "failed to attach mtd%d, error %d",
962 			mtd->index, err);
963 		goto out_free;
964 	}
965 
966 	if (ubi->autoresize_vol_id != -1) {
967 		err = autoresize(ubi, ubi->autoresize_vol_id);
968 		if (err)
969 			goto out_detach;
970 	}
971 
972 	/* Make device "available" before it becomes accessible via sysfs */
973 	ubi_devices[ubi_num] = ubi;
974 
975 	err = uif_init(ubi);
976 	if (err)
977 		goto out_detach;
978 
979 	err = ubi_debugfs_init_dev(ubi);
980 	if (err)
981 		goto out_uif;
982 
983 	ubi->bgt_thread = kthread_create(ubi_thread, ubi, "%s", ubi->bgt_name);
984 	if (IS_ERR(ubi->bgt_thread)) {
985 		err = PTR_ERR(ubi->bgt_thread);
986 		ubi_err(ubi, "cannot spawn \"%s\", error %d",
987 			ubi->bgt_name, err);
988 		goto out_debugfs;
989 	}
990 
991 	ubi_msg(ubi, "attached mtd%d (name \"%s\", size %llu MiB)",
992 		mtd->index, mtd->name, ubi->flash_size >> 20);
993 	ubi_msg(ubi, "PEB size: %d bytes (%d KiB), LEB size: %d bytes",
994 		ubi->peb_size, ubi->peb_size >> 10, ubi->leb_size);
995 	ubi_msg(ubi, "min./max. I/O unit sizes: %d/%d, sub-page size %d",
996 		ubi->min_io_size, ubi->max_write_size, ubi->hdrs_min_io_size);
997 	ubi_msg(ubi, "VID header offset: %d (aligned %d), data offset: %d",
998 		ubi->vid_hdr_offset, ubi->vid_hdr_aloffset, ubi->leb_start);
999 	ubi_msg(ubi, "good PEBs: %d, bad PEBs: %d, corrupted PEBs: %d",
1000 		ubi->good_peb_count, ubi->bad_peb_count, ubi->corr_peb_count);
1001 	ubi_msg(ubi, "user volume: %d, internal volumes: %d, max. volumes count: %d",
1002 		ubi->vol_count - UBI_INT_VOL_COUNT, UBI_INT_VOL_COUNT,
1003 		ubi->vtbl_slots);
1004 	ubi_msg(ubi, "max/mean erase counter: %d/%d, WL threshold: %d, image sequence number: %u",
1005 		ubi->max_ec, ubi->mean_ec, CONFIG_MTD_UBI_WL_THRESHOLD,
1006 		ubi->image_seq);
1007 	ubi_msg(ubi, "available PEBs: %d, total reserved PEBs: %d, PEBs reserved for bad PEB handling: %d",
1008 		ubi->avail_pebs, ubi->rsvd_pebs, ubi->beb_rsvd_pebs);
1009 
1010 	/*
1011 	 * The below lock makes sure we do not race with 'ubi_thread()' which
1012 	 * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
1013 	 */
1014 	spin_lock(&ubi->wl_lock);
1015 	ubi->thread_enabled = 1;
1016 	wake_up_process(ubi->bgt_thread);
1017 	spin_unlock(&ubi->wl_lock);
1018 
1019 	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
1020 	return ubi_num;
1021 
1022 out_debugfs:
1023 	ubi_debugfs_exit_dev(ubi);
1024 out_uif:
1025 	uif_close(ubi);
1026 out_detach:
1027 	ubi_devices[ubi_num] = NULL;
1028 	ubi_wl_close(ubi);
1029 	ubi_free_internal_volumes(ubi);
1030 	vfree(ubi->vtbl);
1031 out_free:
1032 	vfree(ubi->peb_buf);
1033 	vfree(ubi->fm_buf);
1034 	put_device(&ubi->dev);
1035 	return err;
1036 }
1037 
1038 /**
1039  * ubi_detach_mtd_dev - detach an MTD device.
1040  * @ubi_num: UBI device number to detach from
1041  * @anyway: detach MTD even if device reference count is not zero
1042  *
1043  * This function destroys an UBI device number @ubi_num and detaches the
1044  * underlying MTD device. Returns zero in case of success and %-EBUSY if the
1045  * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
1046  * exist.
1047  *
1048  * Note, the invocations of this function has to be serialized by the
1049  * @ubi_devices_mutex.
1050  */
1051 int ubi_detach_mtd_dev(int ubi_num, int anyway)
1052 {
1053 	struct ubi_device *ubi;
1054 
1055 	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
1056 		return -EINVAL;
1057 
1058 	ubi = ubi_get_device(ubi_num);
1059 	if (!ubi)
1060 		return -EINVAL;
1061 
1062 	spin_lock(&ubi_devices_lock);
1063 	put_device(&ubi->dev);
1064 	ubi->ref_count -= 1;
1065 	if (ubi->ref_count) {
1066 		if (!anyway) {
1067 			spin_unlock(&ubi_devices_lock);
1068 			return -EBUSY;
1069 		}
1070 		/* This may only happen if there is a bug */
1071 		ubi_err(ubi, "%s reference count %d, destroy anyway",
1072 			ubi->ubi_name, ubi->ref_count);
1073 	}
1074 	ubi_devices[ubi_num] = NULL;
1075 	spin_unlock(&ubi_devices_lock);
1076 
1077 	ubi_assert(ubi_num == ubi->ubi_num);
1078 	ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
1079 	ubi_msg(ubi, "detaching mtd%d", ubi->mtd->index);
1080 #ifdef CONFIG_MTD_UBI_FASTMAP
1081 	/* If we don't write a new fastmap at detach time we lose all
1082 	 * EC updates that have been made since the last written fastmap.
1083 	 * In case of fastmap debugging we omit the update to simulate an
1084 	 * unclean shutdown. */
1085 	if (!ubi_dbg_chk_fastmap(ubi))
1086 		ubi_update_fastmap(ubi);
1087 #endif
1088 	/*
1089 	 * Before freeing anything, we have to stop the background thread to
1090 	 * prevent it from doing anything on this device while we are freeing.
1091 	 */
1092 	if (ubi->bgt_thread)
1093 		kthread_stop(ubi->bgt_thread);
1094 
1095 #ifdef CONFIG_MTD_UBI_FASTMAP
1096 	cancel_work_sync(&ubi->fm_work);
1097 #endif
1098 	ubi_debugfs_exit_dev(ubi);
1099 	uif_close(ubi);
1100 
1101 	ubi_wl_close(ubi);
1102 	ubi_free_internal_volumes(ubi);
1103 	vfree(ubi->vtbl);
1104 	vfree(ubi->peb_buf);
1105 	vfree(ubi->fm_buf);
1106 	ubi_msg(ubi, "mtd%d is detached", ubi->mtd->index);
1107 	put_mtd_device(ubi->mtd);
1108 	put_device(&ubi->dev);
1109 	return 0;
1110 }
1111 
1112 /**
1113  * open_mtd_by_chdev - open an MTD device by its character device node path.
1114  * @mtd_dev: MTD character device node path
1115  *
1116  * This helper function opens an MTD device by its character node device path.
1117  * Returns MTD device description object in case of success and a negative
1118  * error code in case of failure.
1119  */
1120 static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
1121 {
1122 	int err, minor;
1123 	struct path path;
1124 	struct kstat stat;
1125 
1126 	/* Probably this is an MTD character device node path */
1127 	err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
1128 	if (err)
1129 		return ERR_PTR(err);
1130 
1131 	err = vfs_getattr(&path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
1132 	path_put(&path);
1133 	if (err)
1134 		return ERR_PTR(err);
1135 
1136 	/* MTD device number is defined by the major / minor numbers */
1137 	if (MAJOR(stat.rdev) != MTD_CHAR_MAJOR || !S_ISCHR(stat.mode))
1138 		return ERR_PTR(-EINVAL);
1139 
1140 	minor = MINOR(stat.rdev);
1141 
1142 	if (minor & 1)
1143 		/*
1144 		 * Just do not think the "/dev/mtdrX" devices support is need,
1145 		 * so do not support them to avoid doing extra work.
1146 		 */
1147 		return ERR_PTR(-EINVAL);
1148 
1149 	return get_mtd_device(NULL, minor / 2);
1150 }
1151 
1152 /**
1153  * open_mtd_device - open MTD device by name, character device path, or number.
1154  * @mtd_dev: name, character device node path, or MTD device device number
1155  *
1156  * This function tries to open and MTD device described by @mtd_dev string,
1157  * which is first treated as ASCII MTD device number, and if it is not true, it
1158  * is treated as MTD device name, and if that is also not true, it is treated
1159  * as MTD character device node path. Returns MTD device description object in
1160  * case of success and a negative error code in case of failure.
1161  */
1162 static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
1163 {
1164 	struct mtd_info *mtd;
1165 	int mtd_num;
1166 	char *endp;
1167 
1168 	mtd_num = simple_strtoul(mtd_dev, &endp, 0);
1169 	if (*endp != '\0' || mtd_dev == endp) {
1170 		/*
1171 		 * This does not look like an ASCII integer, probably this is
1172 		 * MTD device name.
1173 		 */
1174 		mtd = get_mtd_device_nm(mtd_dev);
1175 		if (IS_ERR(mtd) && PTR_ERR(mtd) == -ENODEV)
1176 			/* Probably this is an MTD character device node path */
1177 			mtd = open_mtd_by_chdev(mtd_dev);
1178 	} else
1179 		mtd = get_mtd_device(NULL, mtd_num);
1180 
1181 	return mtd;
1182 }
1183 
1184 static int __init ubi_init(void)
1185 {
1186 	int err, i, k;
1187 
1188 	/* Ensure that EC and VID headers have correct size */
1189 	BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
1190 	BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);
1191 
1192 	if (mtd_devs > UBI_MAX_DEVICES) {
1193 		pr_err("UBI error: too many MTD devices, maximum is %d\n",
1194 		       UBI_MAX_DEVICES);
1195 		return -EINVAL;
1196 	}
1197 
1198 	/* Create base sysfs directory and sysfs files */
1199 	err = class_register(&ubi_class);
1200 	if (err < 0)
1201 		return err;
1202 
1203 	err = misc_register(&ubi_ctrl_cdev);
1204 	if (err) {
1205 		pr_err("UBI error: cannot register device\n");
1206 		goto out;
1207 	}
1208 
1209 	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
1210 					      sizeof(struct ubi_wl_entry),
1211 					      0, 0, NULL);
1212 	if (!ubi_wl_entry_slab) {
1213 		err = -ENOMEM;
1214 		goto out_dev_unreg;
1215 	}
1216 
1217 	err = ubi_debugfs_init();
1218 	if (err)
1219 		goto out_slab;
1220 
1221 
1222 	/* Attach MTD devices */
1223 	for (i = 0; i < mtd_devs; i++) {
1224 		struct mtd_dev_param *p = &mtd_dev_param[i];
1225 		struct mtd_info *mtd;
1226 
1227 		cond_resched();
1228 
1229 		mtd = open_mtd_device(p->name);
1230 		if (IS_ERR(mtd)) {
1231 			err = PTR_ERR(mtd);
1232 			pr_err("UBI error: cannot open mtd %s, error %d\n",
1233 			       p->name, err);
1234 			/* See comment below re-ubi_is_module(). */
1235 			if (ubi_is_module())
1236 				goto out_detach;
1237 			continue;
1238 		}
1239 
1240 		mutex_lock(&ubi_devices_mutex);
1241 		err = ubi_attach_mtd_dev(mtd, p->ubi_num,
1242 					 p->vid_hdr_offs, p->max_beb_per1024);
1243 		mutex_unlock(&ubi_devices_mutex);
1244 		if (err < 0) {
1245 			pr_err("UBI error: cannot attach mtd%d\n",
1246 			       mtd->index);
1247 			put_mtd_device(mtd);
1248 
1249 			/*
1250 			 * Originally UBI stopped initializing on any error.
1251 			 * However, later on it was found out that this
1252 			 * behavior is not very good when UBI is compiled into
1253 			 * the kernel and the MTD devices to attach are passed
1254 			 * through the command line. Indeed, UBI failure
1255 			 * stopped whole boot sequence.
1256 			 *
1257 			 * To fix this, we changed the behavior for the
1258 			 * non-module case, but preserved the old behavior for
1259 			 * the module case, just for compatibility. This is a
1260 			 * little inconsistent, though.
1261 			 */
1262 			if (ubi_is_module())
1263 				goto out_detach;
1264 		}
1265 	}
1266 
1267 	err = ubiblock_init();
1268 	if (err) {
1269 		pr_err("UBI error: block: cannot initialize, error %d\n", err);
1270 
1271 		/* See comment above re-ubi_is_module(). */
1272 		if (ubi_is_module())
1273 			goto out_detach;
1274 	}
1275 
1276 	return 0;
1277 
1278 out_detach:
1279 	for (k = 0; k < i; k++)
1280 		if (ubi_devices[k]) {
1281 			mutex_lock(&ubi_devices_mutex);
1282 			ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
1283 			mutex_unlock(&ubi_devices_mutex);
1284 		}
1285 	ubi_debugfs_exit();
1286 out_slab:
1287 	kmem_cache_destroy(ubi_wl_entry_slab);
1288 out_dev_unreg:
1289 	misc_deregister(&ubi_ctrl_cdev);
1290 out:
1291 	class_unregister(&ubi_class);
1292 	pr_err("UBI error: cannot initialize UBI, error %d\n", err);
1293 	return err;
1294 }
1295 late_initcall(ubi_init);
1296 
1297 static void __exit ubi_exit(void)
1298 {
1299 	int i;
1300 
1301 	ubiblock_exit();
1302 
1303 	for (i = 0; i < UBI_MAX_DEVICES; i++)
1304 		if (ubi_devices[i]) {
1305 			mutex_lock(&ubi_devices_mutex);
1306 			ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
1307 			mutex_unlock(&ubi_devices_mutex);
1308 		}
1309 	ubi_debugfs_exit();
1310 	kmem_cache_destroy(ubi_wl_entry_slab);
1311 	misc_deregister(&ubi_ctrl_cdev);
1312 	class_unregister(&ubi_class);
1313 }
1314 module_exit(ubi_exit);
1315 
1316 /**
1317  * bytes_str_to_int - convert a number of bytes string into an integer.
1318  * @str: the string to convert
1319  *
1320  * This function returns positive resulting integer in case of success and a
1321  * negative error code in case of failure.
1322  */
1323 static int bytes_str_to_int(const char *str)
1324 {
1325 	char *endp;
1326 	unsigned long result;
1327 
1328 	result = simple_strtoul(str, &endp, 0);
1329 	if (str == endp || result >= INT_MAX) {
1330 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1331 		return -EINVAL;
1332 	}
1333 
1334 	switch (*endp) {
1335 	case 'G':
1336 		result *= 1024;
1337 		/* fall through */
1338 	case 'M':
1339 		result *= 1024;
1340 		/* fall through */
1341 	case 'K':
1342 		result *= 1024;
1343 		if (endp[1] == 'i' && endp[2] == 'B')
1344 			endp += 2;
1345 	case '\0':
1346 		break;
1347 	default:
1348 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1349 		return -EINVAL;
1350 	}
1351 
1352 	return result;
1353 }
1354 
1355 /**
1356  * ubi_mtd_param_parse - parse the 'mtd=' UBI parameter.
1357  * @val: the parameter value to parse
1358  * @kp: not used
1359  *
1360  * This function returns zero in case of success and a negative error code in
1361  * case of error.
1362  */
1363 static int ubi_mtd_param_parse(const char *val, const struct kernel_param *kp)
1364 {
1365 	int i, len;
1366 	struct mtd_dev_param *p;
1367 	char buf[MTD_PARAM_LEN_MAX];
1368 	char *pbuf = &buf[0];
1369 	char *tokens[MTD_PARAM_MAX_COUNT], *token;
1370 
1371 	if (!val)
1372 		return -EINVAL;
1373 
1374 	if (mtd_devs == UBI_MAX_DEVICES) {
1375 		pr_err("UBI error: too many parameters, max. is %d\n",
1376 		       UBI_MAX_DEVICES);
1377 		return -EINVAL;
1378 	}
1379 
1380 	len = strnlen(val, MTD_PARAM_LEN_MAX);
1381 	if (len == MTD_PARAM_LEN_MAX) {
1382 		pr_err("UBI error: parameter \"%s\" is too long, max. is %d\n",
1383 		       val, MTD_PARAM_LEN_MAX);
1384 		return -EINVAL;
1385 	}
1386 
1387 	if (len == 0) {
1388 		pr_warn("UBI warning: empty 'mtd=' parameter - ignored\n");
1389 		return 0;
1390 	}
1391 
1392 	strcpy(buf, val);
1393 
1394 	/* Get rid of the final newline */
1395 	if (buf[len - 1] == '\n')
1396 		buf[len - 1] = '\0';
1397 
1398 	for (i = 0; i < MTD_PARAM_MAX_COUNT; i++)
1399 		tokens[i] = strsep(&pbuf, ",");
1400 
1401 	if (pbuf) {
1402 		pr_err("UBI error: too many arguments at \"%s\"\n", val);
1403 		return -EINVAL;
1404 	}
1405 
1406 	p = &mtd_dev_param[mtd_devs];
1407 	strcpy(&p->name[0], tokens[0]);
1408 
1409 	token = tokens[1];
1410 	if (token) {
1411 		p->vid_hdr_offs = bytes_str_to_int(token);
1412 
1413 		if (p->vid_hdr_offs < 0)
1414 			return p->vid_hdr_offs;
1415 	}
1416 
1417 	token = tokens[2];
1418 	if (token) {
1419 		int err = kstrtoint(token, 10, &p->max_beb_per1024);
1420 
1421 		if (err) {
1422 			pr_err("UBI error: bad value for max_beb_per1024 parameter: %s",
1423 			       token);
1424 			return -EINVAL;
1425 		}
1426 	}
1427 
1428 	token = tokens[3];
1429 	if (token) {
1430 		int err = kstrtoint(token, 10, &p->ubi_num);
1431 
1432 		if (err) {
1433 			pr_err("UBI error: bad value for ubi_num parameter: %s",
1434 			       token);
1435 			return -EINVAL;
1436 		}
1437 	} else
1438 		p->ubi_num = UBI_DEV_NUM_AUTO;
1439 
1440 	mtd_devs += 1;
1441 	return 0;
1442 }
1443 
1444 module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 0400);
1445 MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024[,ubi_num]]].\n"
1446 		      "Multiple \"mtd\" parameters may be specified.\n"
1447 		      "MTD devices may be specified by their number, name, or path to the MTD character device node.\n"
1448 		      "Optional \"vid_hdr_offs\" parameter specifies UBI VID header position to be used by UBI. (default value if 0)\n"
1449 		      "Optional \"max_beb_per1024\" parameter specifies the maximum expected bad eraseblock per 1024 eraseblocks. (default value ("
1450 		      __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0)\n"
1451 		      "Optional \"ubi_num\" parameter specifies UBI device number which have to be assigned to the newly created UBI device (assigned automatically by default)\n"
1452 		      "\n"
1453 		      "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
1454 		      "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"
1455 		      "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"
1456 		      "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"
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 module_param(fm_debug, bool, 0);
1462 MODULE_PARM_DESC(fm_debug, "Set this parameter to enable fastmap debugging by default. Warning, this will make fastmap slow!");
1463 #endif
1464 MODULE_VERSION(__stringify(UBI_VERSION));
1465 MODULE_DESCRIPTION("UBI - Unsorted Block Images");
1466 MODULE_AUTHOR("Artem Bityutskiy");
1467 MODULE_LICENSE("GPL");
1468