xref: /linux/drivers/mtd/ubi/build.c (revision 0e685c3e7158d35626d6d76b9f859eae806d87fa)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) International Business Machines Corp., 2006
4  * Copyright (c) Nokia Corporation, 2007
5  *
6  * Author: Artem Bityutskiy (Битюцкий Артём),
7  *         Frank Haverkamp
8  */
9 
10 /*
11  * This file includes UBI initialization and building of UBI devices.
12  *
13  * When UBI is initialized, it attaches all the MTD devices specified as the
14  * module load parameters or the kernel boot parameters. If MTD devices were
15  * specified, UBI does not attach any MTD device, but it is possible to do
16  * later using the "UBI control device".
17  */
18 
19 #include <linux/err.h>
20 #include <linux/module.h>
21 #include <linux/moduleparam.h>
22 #include <linux/stringify.h>
23 #include <linux/namei.h>
24 #include <linux/stat.h>
25 #include <linux/miscdevice.h>
26 #include <linux/mtd/partitions.h>
27 #include <linux/log2.h>
28 #include <linux/kthread.h>
29 #include <linux/kernel.h>
30 #include <linux/slab.h>
31 #include <linux/major.h>
32 #include "ubi.h"
33 
34 /* Maximum length of the 'mtd=' parameter */
35 #define MTD_PARAM_LEN_MAX 64
36 
37 /* Maximum number of comma-separated items in the 'mtd=' parameter */
38 #define MTD_PARAM_MAX_COUNT 5
39 
40 /* Maximum value for the number of bad PEBs per 1024 PEBs */
41 #define MAX_MTD_UBI_BEB_LIMIT 768
42 
43 #ifdef CONFIG_MTD_UBI_MODULE
44 #define ubi_is_module() 1
45 #else
46 #define ubi_is_module() 0
47 #endif
48 
49 /**
50  * struct mtd_dev_param - MTD device parameter description data structure.
51  * @name: MTD character device node path, MTD device name, or MTD device number
52  *        string
53  * @ubi_num: UBI number
54  * @vid_hdr_offs: VID header offset
55  * @max_beb_per1024: maximum expected number of bad PEBs per 1024 PEBs
56  * @enable_fm: enable fastmap when value is non-zero
57  */
58 struct mtd_dev_param {
59 	char name[MTD_PARAM_LEN_MAX];
60 	int ubi_num;
61 	int vid_hdr_offs;
62 	int max_beb_per1024;
63 	int enable_fm;
64 };
65 
66 /* Numbers of elements set in the @mtd_dev_param array */
67 static int mtd_devs;
68 
69 /* MTD devices specification parameters */
70 static struct mtd_dev_param mtd_dev_param[UBI_MAX_DEVICES];
71 #ifdef CONFIG_MTD_UBI_FASTMAP
72 /* UBI module parameter to enable fastmap automatically on non-fastmap images */
73 static bool fm_autoconvert;
74 static bool fm_debug;
75 #endif
76 
77 /* Slab cache for wear-leveling entries */
78 struct kmem_cache *ubi_wl_entry_slab;
79 
80 /* UBI control character device */
81 static struct miscdevice ubi_ctrl_cdev = {
82 	.minor = MISC_DYNAMIC_MINOR,
83 	.name = "ubi_ctrl",
84 	.fops = &ubi_ctrl_cdev_operations,
85 };
86 
87 /* All UBI devices in system */
88 static struct ubi_device *ubi_devices[UBI_MAX_DEVICES];
89 
90 /* Serializes UBI devices creations and removals */
91 DEFINE_MUTEX(ubi_devices_mutex);
92 
93 /* Protects @ubi_devices and @ubi->ref_count */
94 static DEFINE_SPINLOCK(ubi_devices_lock);
95 
96 /* "Show" method for files in '/<sysfs>/class/ubi/' */
97 /* UBI version attribute ('/<sysfs>/class/ubi/version') */
98 static ssize_t version_show(struct class *class, struct class_attribute *attr,
99 			    char *buf)
100 {
101 	return sprintf(buf, "%d\n", UBI_VERSION);
102 }
103 static CLASS_ATTR_RO(version);
104 
105 static struct attribute *ubi_class_attrs[] = {
106 	&class_attr_version.attr,
107 	NULL,
108 };
109 ATTRIBUTE_GROUPS(ubi_class);
110 
111 /* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
112 struct class ubi_class = {
113 	.name		= UBI_NAME_STR,
114 	.owner		= THIS_MODULE,
115 	.class_groups	= ubi_class_groups,
116 };
117 
118 static ssize_t dev_attribute_show(struct device *dev,
119 				  struct device_attribute *attr, char *buf);
120 
121 /* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
122 static struct device_attribute dev_eraseblock_size =
123 	__ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
124 static struct device_attribute dev_avail_eraseblocks =
125 	__ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
126 static struct device_attribute dev_total_eraseblocks =
127 	__ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
128 static struct device_attribute dev_volumes_count =
129 	__ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
130 static struct device_attribute dev_max_ec =
131 	__ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
132 static struct device_attribute dev_reserved_for_bad =
133 	__ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
134 static struct device_attribute dev_bad_peb_count =
135 	__ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
136 static struct device_attribute dev_max_vol_count =
137 	__ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
138 static struct device_attribute dev_min_io_size =
139 	__ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
140 static struct device_attribute dev_bgt_enabled =
141 	__ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);
142 static struct device_attribute dev_mtd_num =
143 	__ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
144 static struct device_attribute dev_ro_mode =
145 	__ATTR(ro_mode, S_IRUGO, dev_attribute_show, NULL);
146 
147 /**
148  * ubi_volume_notify - send a volume change notification.
149  * @ubi: UBI device description object
150  * @vol: volume description object of the changed volume
151  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
152  *
153  * This is a helper function which notifies all subscribers about a volume
154  * change event (creation, removal, re-sizing, re-naming, updating). Returns
155  * zero in case of success and a negative error code in case of failure.
156  */
157 int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
158 {
159 	int ret;
160 	struct ubi_notification nt;
161 
162 	ubi_do_get_device_info(ubi, &nt.di);
163 	ubi_do_get_volume_info(ubi, vol, &nt.vi);
164 
165 	switch (ntype) {
166 	case UBI_VOLUME_ADDED:
167 	case UBI_VOLUME_REMOVED:
168 	case UBI_VOLUME_RESIZED:
169 	case UBI_VOLUME_RENAMED:
170 		ret = ubi_update_fastmap(ubi);
171 		if (ret)
172 			ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
173 	}
174 
175 	return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
176 }
177 
178 /**
179  * ubi_notify_all - send a notification to all volumes.
180  * @ubi: UBI device description object
181  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
182  * @nb: the notifier to call
183  *
184  * This function walks all volumes of UBI device @ubi and sends the @ntype
185  * notification for each volume. If @nb is %NULL, then all registered notifiers
186  * are called, otherwise only the @nb notifier is called. Returns the number of
187  * sent notifications.
188  */
189 int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
190 {
191 	struct ubi_notification nt;
192 	int i, count = 0;
193 
194 	ubi_do_get_device_info(ubi, &nt.di);
195 
196 	mutex_lock(&ubi->device_mutex);
197 	for (i = 0; i < ubi->vtbl_slots; i++) {
198 		/*
199 		 * Since the @ubi->device is locked, and we are not going to
200 		 * change @ubi->volumes, we do not have to lock
201 		 * @ubi->volumes_lock.
202 		 */
203 		if (!ubi->volumes[i])
204 			continue;
205 
206 		ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
207 		if (nb)
208 			nb->notifier_call(nb, ntype, &nt);
209 		else
210 			blocking_notifier_call_chain(&ubi_notifiers, ntype,
211 						     &nt);
212 		count += 1;
213 	}
214 	mutex_unlock(&ubi->device_mutex);
215 
216 	return count;
217 }
218 
219 /**
220  * ubi_enumerate_volumes - send "add" notification for all existing volumes.
221  * @nb: the notifier to call
222  *
223  * This function walks all UBI devices and volumes and sends the
224  * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
225  * registered notifiers are called, otherwise only the @nb notifier is called.
226  * Returns the number of sent notifications.
227  */
228 int ubi_enumerate_volumes(struct notifier_block *nb)
229 {
230 	int i, count = 0;
231 
232 	/*
233 	 * Since the @ubi_devices_mutex is locked, and we are not going to
234 	 * change @ubi_devices, we do not have to lock @ubi_devices_lock.
235 	 */
236 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
237 		struct ubi_device *ubi = ubi_devices[i];
238 
239 		if (!ubi)
240 			continue;
241 		count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
242 	}
243 
244 	return count;
245 }
246 
247 /**
248  * ubi_get_device - get UBI device.
249  * @ubi_num: UBI device number
250  *
251  * This function returns UBI device description object for UBI device number
252  * @ubi_num, or %NULL if the device does not exist. This function increases the
253  * device reference count to prevent removal of the device. In other words, the
254  * device cannot be removed if its reference count is not zero.
255  */
256 struct ubi_device *ubi_get_device(int ubi_num)
257 {
258 	struct ubi_device *ubi;
259 
260 	spin_lock(&ubi_devices_lock);
261 	ubi = ubi_devices[ubi_num];
262 	if (ubi) {
263 		ubi_assert(ubi->ref_count >= 0);
264 		ubi->ref_count += 1;
265 		get_device(&ubi->dev);
266 	}
267 	spin_unlock(&ubi_devices_lock);
268 
269 	return ubi;
270 }
271 
272 /**
273  * ubi_put_device - drop an UBI device reference.
274  * @ubi: UBI device description object
275  */
276 void ubi_put_device(struct ubi_device *ubi)
277 {
278 	spin_lock(&ubi_devices_lock);
279 	ubi->ref_count -= 1;
280 	put_device(&ubi->dev);
281 	spin_unlock(&ubi_devices_lock);
282 }
283 
284 /**
285  * ubi_get_by_major - get UBI device by character device major number.
286  * @major: major number
287  *
288  * This function is similar to 'ubi_get_device()', but it searches the device
289  * by its major number.
290  */
291 struct ubi_device *ubi_get_by_major(int major)
292 {
293 	int i;
294 	struct ubi_device *ubi;
295 
296 	spin_lock(&ubi_devices_lock);
297 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
298 		ubi = ubi_devices[i];
299 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
300 			ubi_assert(ubi->ref_count >= 0);
301 			ubi->ref_count += 1;
302 			get_device(&ubi->dev);
303 			spin_unlock(&ubi_devices_lock);
304 			return ubi;
305 		}
306 	}
307 	spin_unlock(&ubi_devices_lock);
308 
309 	return NULL;
310 }
311 
312 /**
313  * ubi_major2num - get UBI device number by character device major number.
314  * @major: major number
315  *
316  * This function searches UBI device number object by its major number. If UBI
317  * device was not found, this function returns -ENODEV, otherwise the UBI device
318  * number is returned.
319  */
320 int ubi_major2num(int major)
321 {
322 	int i, ubi_num = -ENODEV;
323 
324 	spin_lock(&ubi_devices_lock);
325 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
326 		struct ubi_device *ubi = ubi_devices[i];
327 
328 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
329 			ubi_num = ubi->ubi_num;
330 			break;
331 		}
332 	}
333 	spin_unlock(&ubi_devices_lock);
334 
335 	return ubi_num;
336 }
337 
338 /* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
339 static ssize_t dev_attribute_show(struct device *dev,
340 				  struct device_attribute *attr, char *buf)
341 {
342 	ssize_t ret;
343 	struct ubi_device *ubi;
344 
345 	/*
346 	 * The below code looks weird, but it actually makes sense. We get the
347 	 * UBI device reference from the contained 'struct ubi_device'. But it
348 	 * is unclear if the device was removed or not yet. Indeed, if the
349 	 * device was removed before we increased its reference count,
350 	 * 'ubi_get_device()' will return -ENODEV and we fail.
351 	 *
352 	 * Remember, 'struct ubi_device' is freed in the release function, so
353 	 * we still can use 'ubi->ubi_num'.
354 	 */
355 	ubi = container_of(dev, struct ubi_device, dev);
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 if (attr == &dev_ro_mode)
380 		ret = sprintf(buf, "%d\n", ubi->ro_mode);
381 	else
382 		ret = -EINVAL;
383 
384 	return ret;
385 }
386 
387 static struct attribute *ubi_dev_attrs[] = {
388 	&dev_eraseblock_size.attr,
389 	&dev_avail_eraseblocks.attr,
390 	&dev_total_eraseblocks.attr,
391 	&dev_volumes_count.attr,
392 	&dev_max_ec.attr,
393 	&dev_reserved_for_bad.attr,
394 	&dev_bad_peb_count.attr,
395 	&dev_max_vol_count.attr,
396 	&dev_min_io_size.attr,
397 	&dev_bgt_enabled.attr,
398 	&dev_mtd_num.attr,
399 	&dev_ro_mode.attr,
400 	NULL
401 };
402 ATTRIBUTE_GROUPS(ubi_dev);
403 
404 static void dev_release(struct device *dev)
405 {
406 	struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);
407 
408 	kfree(ubi);
409 }
410 
411 /**
412  * kill_volumes - destroy all user volumes.
413  * @ubi: UBI device description object
414  */
415 static void kill_volumes(struct ubi_device *ubi)
416 {
417 	int i;
418 
419 	for (i = 0; i < ubi->vtbl_slots; i++)
420 		if (ubi->volumes[i])
421 			ubi_free_volume(ubi, ubi->volumes[i]);
422 }
423 
424 /**
425  * uif_init - initialize user interfaces for an UBI device.
426  * @ubi: UBI device description object
427  *
428  * This function initializes various user interfaces for an UBI device. If the
429  * initialization fails at an early stage, this function frees all the
430  * resources it allocated, returns an error.
431  *
432  * This function returns zero in case of success and a negative error code in
433  * case of failure.
434  */
435 static int uif_init(struct ubi_device *ubi)
436 {
437 	int i, err;
438 	dev_t dev;
439 
440 	sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);
441 
442 	/*
443 	 * Major numbers for the UBI character devices are allocated
444 	 * dynamically. Major numbers of volume character devices are
445 	 * equivalent to ones of the corresponding UBI character device. Minor
446 	 * numbers of UBI character devices are 0, while minor numbers of
447 	 * volume character devices start from 1. Thus, we allocate one major
448 	 * number and ubi->vtbl_slots + 1 minor numbers.
449 	 */
450 	err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
451 	if (err) {
452 		ubi_err(ubi, "cannot register UBI character devices");
453 		return err;
454 	}
455 
456 	ubi->dev.devt = dev;
457 
458 	ubi_assert(MINOR(dev) == 0);
459 	cdev_init(&ubi->cdev, &ubi_cdev_operations);
460 	dbg_gen("%s major is %u", ubi->ubi_name, MAJOR(dev));
461 	ubi->cdev.owner = THIS_MODULE;
462 
463 	dev_set_name(&ubi->dev, UBI_NAME_STR "%d", ubi->ubi_num);
464 	err = cdev_device_add(&ubi->cdev, &ubi->dev);
465 	if (err)
466 		goto out_unreg;
467 
468 	for (i = 0; i < ubi->vtbl_slots; i++)
469 		if (ubi->volumes[i]) {
470 			err = ubi_add_volume(ubi, ubi->volumes[i]);
471 			if (err) {
472 				ubi_err(ubi, "cannot add volume %d", i);
473 				ubi->volumes[i] = NULL;
474 				goto out_volumes;
475 			}
476 		}
477 
478 	return 0;
479 
480 out_volumes:
481 	kill_volumes(ubi);
482 	cdev_device_del(&ubi->cdev, &ubi->dev);
483 out_unreg:
484 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
485 	ubi_err(ubi, "cannot initialize UBI %s, error %d",
486 		ubi->ubi_name, err);
487 	return err;
488 }
489 
490 /**
491  * uif_close - close user interfaces for an UBI device.
492  * @ubi: UBI device description object
493  *
494  * Note, since this function un-registers UBI volume device objects (@vol->dev),
495  * the memory allocated voe the volumes is freed as well (in the release
496  * function).
497  */
498 static void uif_close(struct ubi_device *ubi)
499 {
500 	kill_volumes(ubi);
501 	cdev_device_del(&ubi->cdev, &ubi->dev);
502 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
503 }
504 
505 /**
506  * ubi_free_volumes_from - free volumes from specific index.
507  * @ubi: UBI device description object
508  * @from: the start index used for volume free.
509  */
510 static void ubi_free_volumes_from(struct ubi_device *ubi, int from)
511 {
512 	int i;
513 
514 	for (i = from; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
515 		if (!ubi->volumes[i])
516 			continue;
517 		ubi_eba_replace_table(ubi->volumes[i], NULL);
518 		ubi_fastmap_destroy_checkmap(ubi->volumes[i]);
519 		kfree(ubi->volumes[i]);
520 		ubi->volumes[i] = NULL;
521 	}
522 }
523 
524 /**
525  * ubi_free_all_volumes - free all volumes.
526  * @ubi: UBI device description object
527  */
528 void ubi_free_all_volumes(struct ubi_device *ubi)
529 {
530 	ubi_free_volumes_from(ubi, 0);
531 }
532 
533 /**
534  * ubi_free_internal_volumes - free internal volumes.
535  * @ubi: UBI device description object
536  */
537 void ubi_free_internal_volumes(struct ubi_device *ubi)
538 {
539 	ubi_free_volumes_from(ubi, ubi->vtbl_slots);
540 }
541 
542 static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
543 {
544 	int limit, device_pebs;
545 	uint64_t device_size;
546 
547 	if (!max_beb_per1024) {
548 		/*
549 		 * Since max_beb_per1024 has not been set by the user in either
550 		 * the cmdline or Kconfig, use mtd_max_bad_blocks to set the
551 		 * limit if it is supported by the device.
552 		 */
553 		limit = mtd_max_bad_blocks(ubi->mtd, 0, ubi->mtd->size);
554 		if (limit < 0)
555 			return 0;
556 		return limit;
557 	}
558 
559 	/*
560 	 * Here we are using size of the entire flash chip and
561 	 * not just the MTD partition size because the maximum
562 	 * number of bad eraseblocks is a percentage of the
563 	 * whole device and bad eraseblocks are not fairly
564 	 * distributed over the flash chip. So the worst case
565 	 * is that all the bad eraseblocks of the chip are in
566 	 * the MTD partition we are attaching (ubi->mtd).
567 	 */
568 	device_size = mtd_get_device_size(ubi->mtd);
569 	device_pebs = mtd_div_by_eb(device_size, ubi->mtd);
570 	limit = mult_frac(device_pebs, max_beb_per1024, 1024);
571 
572 	/* Round it up */
573 	if (mult_frac(limit, 1024, max_beb_per1024) < device_pebs)
574 		limit += 1;
575 
576 	return limit;
577 }
578 
579 /**
580  * io_init - initialize I/O sub-system for a given UBI device.
581  * @ubi: UBI device description object
582  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
583  *
584  * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
585  * assumed:
586  *   o EC header is always at offset zero - this cannot be changed;
587  *   o VID header starts just after the EC header at the closest address
588  *     aligned to @io->hdrs_min_io_size;
589  *   o data starts just after the VID header at the closest address aligned to
590  *     @io->min_io_size
591  *
592  * This function returns zero in case of success and a negative error code in
593  * case of failure.
594  */
595 static int io_init(struct ubi_device *ubi, int max_beb_per1024)
596 {
597 	dbg_gen("sizeof(struct ubi_ainf_peb) %zu", sizeof(struct ubi_ainf_peb));
598 	dbg_gen("sizeof(struct ubi_wl_entry) %zu", sizeof(struct ubi_wl_entry));
599 
600 	if (ubi->mtd->numeraseregions != 0) {
601 		/*
602 		 * Some flashes have several erase regions. Different regions
603 		 * may have different eraseblock size and other
604 		 * characteristics. It looks like mostly multi-region flashes
605 		 * have one "main" region and one or more small regions to
606 		 * store boot loader code or boot parameters or whatever. I
607 		 * guess we should just pick the largest region. But this is
608 		 * not implemented.
609 		 */
610 		ubi_err(ubi, "multiple regions, not implemented");
611 		return -EINVAL;
612 	}
613 
614 	if (ubi->vid_hdr_offset < 0)
615 		return -EINVAL;
616 
617 	/*
618 	 * Note, in this implementation we support MTD devices with 0x7FFFFFFF
619 	 * physical eraseblocks maximum.
620 	 */
621 
622 	ubi->peb_size   = ubi->mtd->erasesize;
623 	ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
624 	ubi->flash_size = ubi->mtd->size;
625 
626 	if (mtd_can_have_bb(ubi->mtd)) {
627 		ubi->bad_allowed = 1;
628 		ubi->bad_peb_limit = get_bad_peb_limit(ubi, max_beb_per1024);
629 	}
630 
631 	if (ubi->mtd->type == MTD_NORFLASH)
632 		ubi->nor_flash = 1;
633 
634 	ubi->min_io_size = ubi->mtd->writesize;
635 	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
636 
637 	/*
638 	 * Make sure minimal I/O unit is power of 2. Note, there is no
639 	 * fundamental reason for this assumption. It is just an optimization
640 	 * which allows us to avoid costly division operations.
641 	 */
642 	if (!is_power_of_2(ubi->min_io_size)) {
643 		ubi_err(ubi, "min. I/O unit (%d) is not power of 2",
644 			ubi->min_io_size);
645 		return -EINVAL;
646 	}
647 
648 	ubi_assert(ubi->hdrs_min_io_size > 0);
649 	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
650 	ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
651 
652 	ubi->max_write_size = ubi->mtd->writebufsize;
653 	/*
654 	 * Maximum write size has to be greater or equivalent to min. I/O
655 	 * size, and be multiple of min. I/O size.
656 	 */
657 	if (ubi->max_write_size < ubi->min_io_size ||
658 	    ubi->max_write_size % ubi->min_io_size ||
659 	    !is_power_of_2(ubi->max_write_size)) {
660 		ubi_err(ubi, "bad write buffer size %d for %d min. I/O unit",
661 			ubi->max_write_size, ubi->min_io_size);
662 		return -EINVAL;
663 	}
664 
665 	/* Calculate default aligned sizes of EC and VID headers */
666 	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
667 	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
668 
669 	if (ubi->vid_hdr_offset && ((ubi->vid_hdr_offset + UBI_VID_HDR_SIZE) >
670 	    ubi->vid_hdr_alsize)) {
671 		ubi_err(ubi, "VID header offset %d too large.", ubi->vid_hdr_offset);
672 		return -EINVAL;
673 	}
674 
675 	dbg_gen("min_io_size      %d", ubi->min_io_size);
676 	dbg_gen("max_write_size   %d", ubi->max_write_size);
677 	dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
678 	dbg_gen("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
679 	dbg_gen("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
680 
681 	if (ubi->vid_hdr_offset == 0)
682 		/* Default offset */
683 		ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
684 				      ubi->ec_hdr_alsize;
685 	else {
686 		ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
687 						~(ubi->hdrs_min_io_size - 1);
688 		ubi->vid_hdr_shift = ubi->vid_hdr_offset -
689 						ubi->vid_hdr_aloffset;
690 	}
691 
692 	/* Similar for the data offset */
693 	ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
694 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
695 
696 	dbg_gen("vid_hdr_offset   %d", ubi->vid_hdr_offset);
697 	dbg_gen("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
698 	dbg_gen("vid_hdr_shift    %d", ubi->vid_hdr_shift);
699 	dbg_gen("leb_start        %d", ubi->leb_start);
700 
701 	/* The shift must be aligned to 32-bit boundary */
702 	if (ubi->vid_hdr_shift % 4) {
703 		ubi_err(ubi, "unaligned VID header shift %d",
704 			ubi->vid_hdr_shift);
705 		return -EINVAL;
706 	}
707 
708 	/* Check sanity */
709 	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
710 	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
711 	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
712 	    ubi->leb_start & (ubi->min_io_size - 1)) {
713 		ubi_err(ubi, "bad VID header (%d) or data offsets (%d)",
714 			ubi->vid_hdr_offset, ubi->leb_start);
715 		return -EINVAL;
716 	}
717 
718 	/*
719 	 * Set maximum amount of physical erroneous eraseblocks to be 10%.
720 	 * Erroneous PEB are those which have read errors.
721 	 */
722 	ubi->max_erroneous = ubi->peb_count / 10;
723 	if (ubi->max_erroneous < 16)
724 		ubi->max_erroneous = 16;
725 	dbg_gen("max_erroneous    %d", ubi->max_erroneous);
726 
727 	/*
728 	 * It may happen that EC and VID headers are situated in one minimal
729 	 * I/O unit. In this case we can only accept this UBI image in
730 	 * read-only mode.
731 	 */
732 	if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
733 		ubi_warn(ubi, "EC and VID headers are in the same minimal I/O unit, switch to read-only mode");
734 		ubi->ro_mode = 1;
735 	}
736 
737 	ubi->leb_size = ubi->peb_size - ubi->leb_start;
738 
739 	if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
740 		ubi_msg(ubi, "MTD device %d is write-protected, attach in read-only mode",
741 			ubi->mtd->index);
742 		ubi->ro_mode = 1;
743 	}
744 
745 	/*
746 	 * Note, ideally, we have to initialize @ubi->bad_peb_count here. But
747 	 * unfortunately, MTD does not provide this information. We should loop
748 	 * over all physical eraseblocks and invoke mtd->block_is_bad() for
749 	 * each physical eraseblock. So, we leave @ubi->bad_peb_count
750 	 * uninitialized so far.
751 	 */
752 
753 	return 0;
754 }
755 
756 /**
757  * autoresize - re-size the volume which has the "auto-resize" flag set.
758  * @ubi: UBI device description object
759  * @vol_id: ID of the volume to re-size
760  *
761  * This function re-sizes the volume marked by the %UBI_VTBL_AUTORESIZE_FLG in
762  * the volume table to the largest possible size. See comments in ubi-header.h
763  * for more description of the flag. Returns zero in case of success and a
764  * negative error code in case of failure.
765  */
766 static int autoresize(struct ubi_device *ubi, int vol_id)
767 {
768 	struct ubi_volume_desc desc;
769 	struct ubi_volume *vol = ubi->volumes[vol_id];
770 	int err, old_reserved_pebs = vol->reserved_pebs;
771 
772 	if (ubi->ro_mode) {
773 		ubi_warn(ubi, "skip auto-resize because of R/O mode");
774 		return 0;
775 	}
776 
777 	/*
778 	 * Clear the auto-resize flag in the volume in-memory copy of the
779 	 * volume table, and 'ubi_resize_volume()' will propagate this change
780 	 * to the flash.
781 	 */
782 	ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;
783 
784 	if (ubi->avail_pebs == 0) {
785 		struct ubi_vtbl_record vtbl_rec;
786 
787 		/*
788 		 * No available PEBs to re-size the volume, clear the flag on
789 		 * flash and exit.
790 		 */
791 		vtbl_rec = ubi->vtbl[vol_id];
792 		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
793 		if (err)
794 			ubi_err(ubi, "cannot clean auto-resize flag for volume %d",
795 				vol_id);
796 	} else {
797 		desc.vol = vol;
798 		err = ubi_resize_volume(&desc,
799 					old_reserved_pebs + ubi->avail_pebs);
800 		if (err)
801 			ubi_err(ubi, "cannot auto-resize volume %d",
802 				vol_id);
803 	}
804 
805 	if (err)
806 		return err;
807 
808 	ubi_msg(ubi, "volume %d (\"%s\") re-sized from %d to %d LEBs",
809 		vol_id, vol->name, old_reserved_pebs, vol->reserved_pebs);
810 	return 0;
811 }
812 
813 /**
814  * ubi_attach_mtd_dev - attach an MTD device.
815  * @mtd: MTD device description object
816  * @ubi_num: number to assign to the new UBI device
817  * @vid_hdr_offset: VID header offset
818  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
819  * @disable_fm: whether disable fastmap
820  *
821  * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
822  * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
823  * which case this function finds a vacant device number and assigns it
824  * automatically. Returns the new UBI device number in case of success and a
825  * negative error code in case of failure.
826  *
827  * If @disable_fm is true, ubi doesn't create new fastmap even the module param
828  * 'fm_autoconvert' is set, and existed old fastmap will be destroyed after
829  * doing full scanning.
830  *
831  * Note, the invocations of this function has to be serialized by the
832  * @ubi_devices_mutex.
833  */
834 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
835 		       int vid_hdr_offset, int max_beb_per1024, bool disable_fm)
836 {
837 	struct ubi_device *ubi;
838 	int i, err;
839 
840 	if (max_beb_per1024 < 0 || max_beb_per1024 > MAX_MTD_UBI_BEB_LIMIT)
841 		return -EINVAL;
842 
843 	if (!max_beb_per1024)
844 		max_beb_per1024 = CONFIG_MTD_UBI_BEB_LIMIT;
845 
846 	/*
847 	 * Check if we already have the same MTD device attached.
848 	 *
849 	 * Note, this function assumes that UBI devices creations and deletions
850 	 * are serialized, so it does not take the &ubi_devices_lock.
851 	 */
852 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
853 		ubi = ubi_devices[i];
854 		if (ubi && mtd->index == ubi->mtd->index) {
855 			pr_err("ubi: mtd%d is already attached to ubi%d\n",
856 				mtd->index, i);
857 			return -EEXIST;
858 		}
859 	}
860 
861 	/*
862 	 * Make sure this MTD device is not emulated on top of an UBI volume
863 	 * already. Well, generally this recursion works fine, but there are
864 	 * different problems like the UBI module takes a reference to itself
865 	 * by attaching (and thus, opening) the emulated MTD device. This
866 	 * results in inability to unload the module. And in general it makes
867 	 * no sense to attach emulated MTD devices, so we prohibit this.
868 	 */
869 	if (mtd->type == MTD_UBIVOLUME) {
870 		pr_err("ubi: refuse attaching mtd%d - it is already emulated on top of UBI\n",
871 			mtd->index);
872 		return -EINVAL;
873 	}
874 
875 	/*
876 	 * Both UBI and UBIFS have been designed for SLC NAND and NOR flashes.
877 	 * MLC NAND is different and needs special care, otherwise UBI or UBIFS
878 	 * will die soon and you will lose all your data.
879 	 * Relax this rule if the partition we're attaching to operates in SLC
880 	 * mode.
881 	 */
882 	if (mtd->type == MTD_MLCNANDFLASH &&
883 	    !(mtd->flags & MTD_SLC_ON_MLC_EMULATION)) {
884 		pr_err("ubi: refuse attaching mtd%d - MLC NAND is not supported\n",
885 			mtd->index);
886 		return -EINVAL;
887 	}
888 
889 	if (ubi_num == UBI_DEV_NUM_AUTO) {
890 		/* Search for an empty slot in the @ubi_devices array */
891 		for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
892 			if (!ubi_devices[ubi_num])
893 				break;
894 		if (ubi_num == UBI_MAX_DEVICES) {
895 			pr_err("ubi: only %d UBI devices may be created\n",
896 				UBI_MAX_DEVICES);
897 			return -ENFILE;
898 		}
899 	} else {
900 		if (ubi_num >= UBI_MAX_DEVICES)
901 			return -EINVAL;
902 
903 		/* Make sure ubi_num is not busy */
904 		if (ubi_devices[ubi_num]) {
905 			pr_err("ubi: ubi%i already exists\n", ubi_num);
906 			return -EEXIST;
907 		}
908 	}
909 
910 	ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
911 	if (!ubi)
912 		return -ENOMEM;
913 
914 	device_initialize(&ubi->dev);
915 	ubi->dev.release = dev_release;
916 	ubi->dev.class = &ubi_class;
917 	ubi->dev.groups = ubi_dev_groups;
918 	ubi->dev.parent = &mtd->dev;
919 
920 	ubi->mtd = mtd;
921 	ubi->ubi_num = ubi_num;
922 	ubi->vid_hdr_offset = vid_hdr_offset;
923 	ubi->autoresize_vol_id = -1;
924 
925 #ifdef CONFIG_MTD_UBI_FASTMAP
926 	ubi->fm_pool.used = ubi->fm_pool.size = 0;
927 	ubi->fm_wl_pool.used = ubi->fm_wl_pool.size = 0;
928 
929 	/*
930 	 * fm_pool.max_size is 5% of the total number of PEBs but it's also
931 	 * between UBI_FM_MAX_POOL_SIZE and UBI_FM_MIN_POOL_SIZE.
932 	 */
933 	ubi->fm_pool.max_size = min(((int)mtd_div_by_eb(ubi->mtd->size,
934 		ubi->mtd) / 100) * 5, UBI_FM_MAX_POOL_SIZE);
935 	ubi->fm_pool.max_size = max(ubi->fm_pool.max_size,
936 		UBI_FM_MIN_POOL_SIZE);
937 
938 	ubi->fm_wl_pool.max_size = ubi->fm_pool.max_size / 2;
939 	ubi->fm_disabled = (!fm_autoconvert || disable_fm) ? 1 : 0;
940 	if (fm_debug)
941 		ubi_enable_dbg_chk_fastmap(ubi);
942 
943 	if (!ubi->fm_disabled && (int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd)
944 	    <= UBI_FM_MAX_START) {
945 		ubi_err(ubi, "More than %i PEBs are needed for fastmap, sorry.",
946 			UBI_FM_MAX_START);
947 		ubi->fm_disabled = 1;
948 	}
949 
950 	ubi_msg(ubi, "default fastmap pool size: %d", ubi->fm_pool.max_size);
951 	ubi_msg(ubi, "default fastmap WL pool size: %d",
952 		ubi->fm_wl_pool.max_size);
953 #else
954 	ubi->fm_disabled = 1;
955 #endif
956 	mutex_init(&ubi->buf_mutex);
957 	mutex_init(&ubi->ckvol_mutex);
958 	mutex_init(&ubi->device_mutex);
959 	spin_lock_init(&ubi->volumes_lock);
960 	init_rwsem(&ubi->fm_protect);
961 	init_rwsem(&ubi->fm_eba_sem);
962 
963 	ubi_msg(ubi, "attaching mtd%d", mtd->index);
964 
965 	err = io_init(ubi, max_beb_per1024);
966 	if (err)
967 		goto out_free;
968 
969 	err = -ENOMEM;
970 	ubi->peb_buf = vmalloc(ubi->peb_size);
971 	if (!ubi->peb_buf)
972 		goto out_free;
973 
974 #ifdef CONFIG_MTD_UBI_FASTMAP
975 	ubi->fm_size = ubi_calc_fm_size(ubi);
976 	ubi->fm_buf = vzalloc(ubi->fm_size);
977 	if (!ubi->fm_buf)
978 		goto out_free;
979 #endif
980 	err = ubi_attach(ubi, disable_fm ? 1 : 0);
981 	if (err) {
982 		ubi_err(ubi, "failed to attach mtd%d, error %d",
983 			mtd->index, err);
984 		goto out_free;
985 	}
986 
987 	if (ubi->autoresize_vol_id != -1) {
988 		err = autoresize(ubi, ubi->autoresize_vol_id);
989 		if (err)
990 			goto out_detach;
991 	}
992 
993 	err = uif_init(ubi);
994 	if (err)
995 		goto out_detach;
996 
997 	err = ubi_debugfs_init_dev(ubi);
998 	if (err)
999 		goto out_uif;
1000 
1001 	ubi->bgt_thread = kthread_create(ubi_thread, ubi, "%s", ubi->bgt_name);
1002 	if (IS_ERR(ubi->bgt_thread)) {
1003 		err = PTR_ERR(ubi->bgt_thread);
1004 		ubi_err(ubi, "cannot spawn \"%s\", error %d",
1005 			ubi->bgt_name, err);
1006 		goto out_debugfs;
1007 	}
1008 
1009 	ubi_msg(ubi, "attached mtd%d (name \"%s\", size %llu MiB)",
1010 		mtd->index, mtd->name, ubi->flash_size >> 20);
1011 	ubi_msg(ubi, "PEB size: %d bytes (%d KiB), LEB size: %d bytes",
1012 		ubi->peb_size, ubi->peb_size >> 10, ubi->leb_size);
1013 	ubi_msg(ubi, "min./max. I/O unit sizes: %d/%d, sub-page size %d",
1014 		ubi->min_io_size, ubi->max_write_size, ubi->hdrs_min_io_size);
1015 	ubi_msg(ubi, "VID header offset: %d (aligned %d), data offset: %d",
1016 		ubi->vid_hdr_offset, ubi->vid_hdr_aloffset, ubi->leb_start);
1017 	ubi_msg(ubi, "good PEBs: %d, bad PEBs: %d, corrupted PEBs: %d",
1018 		ubi->good_peb_count, ubi->bad_peb_count, ubi->corr_peb_count);
1019 	ubi_msg(ubi, "user volume: %d, internal volumes: %d, max. volumes count: %d",
1020 		ubi->vol_count - UBI_INT_VOL_COUNT, UBI_INT_VOL_COUNT,
1021 		ubi->vtbl_slots);
1022 	ubi_msg(ubi, "max/mean erase counter: %d/%d, WL threshold: %d, image sequence number: %u",
1023 		ubi->max_ec, ubi->mean_ec, CONFIG_MTD_UBI_WL_THRESHOLD,
1024 		ubi->image_seq);
1025 	ubi_msg(ubi, "available PEBs: %d, total reserved PEBs: %d, PEBs reserved for bad PEB handling: %d",
1026 		ubi->avail_pebs, ubi->rsvd_pebs, ubi->beb_rsvd_pebs);
1027 
1028 	/*
1029 	 * The below lock makes sure we do not race with 'ubi_thread()' which
1030 	 * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
1031 	 */
1032 	spin_lock(&ubi->wl_lock);
1033 	ubi->thread_enabled = 1;
1034 	wake_up_process(ubi->bgt_thread);
1035 	spin_unlock(&ubi->wl_lock);
1036 
1037 	ubi_devices[ubi_num] = ubi;
1038 	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
1039 	return ubi_num;
1040 
1041 out_debugfs:
1042 	ubi_debugfs_exit_dev(ubi);
1043 out_uif:
1044 	uif_close(ubi);
1045 out_detach:
1046 	ubi_wl_close(ubi);
1047 	ubi_free_all_volumes(ubi);
1048 	vfree(ubi->vtbl);
1049 out_free:
1050 	vfree(ubi->peb_buf);
1051 	vfree(ubi->fm_buf);
1052 	put_device(&ubi->dev);
1053 	return err;
1054 }
1055 
1056 /**
1057  * ubi_detach_mtd_dev - detach an MTD device.
1058  * @ubi_num: UBI device number to detach from
1059  * @anyway: detach MTD even if device reference count is not zero
1060  *
1061  * This function destroys an UBI device number @ubi_num and detaches the
1062  * underlying MTD device. Returns zero in case of success and %-EBUSY if the
1063  * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
1064  * exist.
1065  *
1066  * Note, the invocations of this function has to be serialized by the
1067  * @ubi_devices_mutex.
1068  */
1069 int ubi_detach_mtd_dev(int ubi_num, int anyway)
1070 {
1071 	struct ubi_device *ubi;
1072 
1073 	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
1074 		return -EINVAL;
1075 
1076 	ubi = ubi_get_device(ubi_num);
1077 	if (!ubi)
1078 		return -EINVAL;
1079 
1080 	spin_lock(&ubi_devices_lock);
1081 	put_device(&ubi->dev);
1082 	ubi->ref_count -= 1;
1083 	if (ubi->ref_count) {
1084 		if (!anyway) {
1085 			spin_unlock(&ubi_devices_lock);
1086 			return -EBUSY;
1087 		}
1088 		/* This may only happen if there is a bug */
1089 		ubi_err(ubi, "%s reference count %d, destroy anyway",
1090 			ubi->ubi_name, ubi->ref_count);
1091 	}
1092 	ubi_devices[ubi_num] = NULL;
1093 	spin_unlock(&ubi_devices_lock);
1094 
1095 	ubi_assert(ubi_num == ubi->ubi_num);
1096 	ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
1097 	ubi_msg(ubi, "detaching mtd%d", ubi->mtd->index);
1098 #ifdef CONFIG_MTD_UBI_FASTMAP
1099 	/* If we don't write a new fastmap at detach time we lose all
1100 	 * EC updates that have been made since the last written fastmap.
1101 	 * In case of fastmap debugging we omit the update to simulate an
1102 	 * unclean shutdown. */
1103 	if (!ubi_dbg_chk_fastmap(ubi))
1104 		ubi_update_fastmap(ubi);
1105 #endif
1106 	/*
1107 	 * Before freeing anything, we have to stop the background thread to
1108 	 * prevent it from doing anything on this device while we are freeing.
1109 	 */
1110 	if (ubi->bgt_thread)
1111 		kthread_stop(ubi->bgt_thread);
1112 
1113 #ifdef CONFIG_MTD_UBI_FASTMAP
1114 	cancel_work_sync(&ubi->fm_work);
1115 #endif
1116 	ubi_debugfs_exit_dev(ubi);
1117 	uif_close(ubi);
1118 
1119 	ubi_wl_close(ubi);
1120 	ubi_free_internal_volumes(ubi);
1121 	vfree(ubi->vtbl);
1122 	vfree(ubi->peb_buf);
1123 	vfree(ubi->fm_buf);
1124 	ubi_msg(ubi, "mtd%d is detached", ubi->mtd->index);
1125 	put_mtd_device(ubi->mtd);
1126 	put_device(&ubi->dev);
1127 	return 0;
1128 }
1129 
1130 /**
1131  * open_mtd_by_chdev - open an MTD device by its character device node path.
1132  * @mtd_dev: MTD character device node path
1133  *
1134  * This helper function opens an MTD device by its character node device path.
1135  * Returns MTD device description object in case of success and a negative
1136  * error code in case of failure.
1137  */
1138 static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
1139 {
1140 	int err, minor;
1141 	struct path path;
1142 	struct kstat stat;
1143 
1144 	/* Probably this is an MTD character device node path */
1145 	err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
1146 	if (err)
1147 		return ERR_PTR(err);
1148 
1149 	err = vfs_getattr(&path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
1150 	path_put(&path);
1151 	if (err)
1152 		return ERR_PTR(err);
1153 
1154 	/* MTD device number is defined by the major / minor numbers */
1155 	if (MAJOR(stat.rdev) != MTD_CHAR_MAJOR || !S_ISCHR(stat.mode))
1156 		return ERR_PTR(-EINVAL);
1157 
1158 	minor = MINOR(stat.rdev);
1159 
1160 	if (minor & 1)
1161 		/*
1162 		 * Just do not think the "/dev/mtdrX" devices support is need,
1163 		 * so do not support them to avoid doing extra work.
1164 		 */
1165 		return ERR_PTR(-EINVAL);
1166 
1167 	return get_mtd_device(NULL, minor / 2);
1168 }
1169 
1170 /**
1171  * open_mtd_device - open MTD device by name, character device path, or number.
1172  * @mtd_dev: name, character device node path, or MTD device device number
1173  *
1174  * This function tries to open and MTD device described by @mtd_dev string,
1175  * which is first treated as ASCII MTD device number, and if it is not true, it
1176  * is treated as MTD device name, and if that is also not true, it is treated
1177  * as MTD character device node path. Returns MTD device description object in
1178  * case of success and a negative error code in case of failure.
1179  */
1180 static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
1181 {
1182 	struct mtd_info *mtd;
1183 	int mtd_num;
1184 	char *endp;
1185 
1186 	mtd_num = simple_strtoul(mtd_dev, &endp, 0);
1187 	if (*endp != '\0' || mtd_dev == endp) {
1188 		/*
1189 		 * This does not look like an ASCII integer, probably this is
1190 		 * MTD device name.
1191 		 */
1192 		mtd = get_mtd_device_nm(mtd_dev);
1193 		if (PTR_ERR(mtd) == -ENODEV)
1194 			/* Probably this is an MTD character device node path */
1195 			mtd = open_mtd_by_chdev(mtd_dev);
1196 	} else
1197 		mtd = get_mtd_device(NULL, mtd_num);
1198 
1199 	return mtd;
1200 }
1201 
1202 static int __init ubi_init(void)
1203 {
1204 	int err, i, k;
1205 
1206 	/* Ensure that EC and VID headers have correct size */
1207 	BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
1208 	BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);
1209 
1210 	if (mtd_devs > UBI_MAX_DEVICES) {
1211 		pr_err("UBI error: too many MTD devices, maximum is %d\n",
1212 		       UBI_MAX_DEVICES);
1213 		return -EINVAL;
1214 	}
1215 
1216 	/* Create base sysfs directory and sysfs files */
1217 	err = class_register(&ubi_class);
1218 	if (err < 0)
1219 		return err;
1220 
1221 	err = misc_register(&ubi_ctrl_cdev);
1222 	if (err) {
1223 		pr_err("UBI error: cannot register device\n");
1224 		goto out;
1225 	}
1226 
1227 	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
1228 					      sizeof(struct ubi_wl_entry),
1229 					      0, 0, NULL);
1230 	if (!ubi_wl_entry_slab) {
1231 		err = -ENOMEM;
1232 		goto out_dev_unreg;
1233 	}
1234 
1235 	err = ubi_debugfs_init();
1236 	if (err)
1237 		goto out_slab;
1238 
1239 
1240 	/* Attach MTD devices */
1241 	for (i = 0; i < mtd_devs; i++) {
1242 		struct mtd_dev_param *p = &mtd_dev_param[i];
1243 		struct mtd_info *mtd;
1244 
1245 		cond_resched();
1246 
1247 		mtd = open_mtd_device(p->name);
1248 		if (IS_ERR(mtd)) {
1249 			err = PTR_ERR(mtd);
1250 			pr_err("UBI error: cannot open mtd %s, error %d\n",
1251 			       p->name, err);
1252 			/* See comment below re-ubi_is_module(). */
1253 			if (ubi_is_module())
1254 				goto out_detach;
1255 			continue;
1256 		}
1257 
1258 		mutex_lock(&ubi_devices_mutex);
1259 		err = ubi_attach_mtd_dev(mtd, p->ubi_num,
1260 					 p->vid_hdr_offs, p->max_beb_per1024,
1261 					 p->enable_fm == 0 ? true : false);
1262 		mutex_unlock(&ubi_devices_mutex);
1263 		if (err < 0) {
1264 			pr_err("UBI error: cannot attach mtd%d\n",
1265 			       mtd->index);
1266 			put_mtd_device(mtd);
1267 
1268 			/*
1269 			 * Originally UBI stopped initializing on any error.
1270 			 * However, later on it was found out that this
1271 			 * behavior is not very good when UBI is compiled into
1272 			 * the kernel and the MTD devices to attach are passed
1273 			 * through the command line. Indeed, UBI failure
1274 			 * stopped whole boot sequence.
1275 			 *
1276 			 * To fix this, we changed the behavior for the
1277 			 * non-module case, but preserved the old behavior for
1278 			 * the module case, just for compatibility. This is a
1279 			 * little inconsistent, though.
1280 			 */
1281 			if (ubi_is_module())
1282 				goto out_detach;
1283 		}
1284 	}
1285 
1286 	err = ubiblock_init();
1287 	if (err) {
1288 		pr_err("UBI error: block: cannot initialize, error %d\n", err);
1289 
1290 		/* See comment above re-ubi_is_module(). */
1291 		if (ubi_is_module())
1292 			goto out_detach;
1293 	}
1294 
1295 	return 0;
1296 
1297 out_detach:
1298 	for (k = 0; k < i; k++)
1299 		if (ubi_devices[k]) {
1300 			mutex_lock(&ubi_devices_mutex);
1301 			ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
1302 			mutex_unlock(&ubi_devices_mutex);
1303 		}
1304 	ubi_debugfs_exit();
1305 out_slab:
1306 	kmem_cache_destroy(ubi_wl_entry_slab);
1307 out_dev_unreg:
1308 	misc_deregister(&ubi_ctrl_cdev);
1309 out:
1310 	class_unregister(&ubi_class);
1311 	pr_err("UBI error: cannot initialize UBI, error %d\n", err);
1312 	return err;
1313 }
1314 late_initcall(ubi_init);
1315 
1316 static void __exit ubi_exit(void)
1317 {
1318 	int i;
1319 
1320 	ubiblock_exit();
1321 
1322 	for (i = 0; i < UBI_MAX_DEVICES; i++)
1323 		if (ubi_devices[i]) {
1324 			mutex_lock(&ubi_devices_mutex);
1325 			ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
1326 			mutex_unlock(&ubi_devices_mutex);
1327 		}
1328 	ubi_debugfs_exit();
1329 	kmem_cache_destroy(ubi_wl_entry_slab);
1330 	misc_deregister(&ubi_ctrl_cdev);
1331 	class_unregister(&ubi_class);
1332 }
1333 module_exit(ubi_exit);
1334 
1335 /**
1336  * bytes_str_to_int - convert a number of bytes string into an integer.
1337  * @str: the string to convert
1338  *
1339  * This function returns positive resulting integer in case of success and a
1340  * negative error code in case of failure.
1341  */
1342 static int bytes_str_to_int(const char *str)
1343 {
1344 	char *endp;
1345 	unsigned long result;
1346 
1347 	result = simple_strtoul(str, &endp, 0);
1348 	if (str == endp || result >= INT_MAX) {
1349 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1350 		return -EINVAL;
1351 	}
1352 
1353 	switch (*endp) {
1354 	case 'G':
1355 		result *= 1024;
1356 		fallthrough;
1357 	case 'M':
1358 		result *= 1024;
1359 		fallthrough;
1360 	case 'K':
1361 		result *= 1024;
1362 		break;
1363 	case '\0':
1364 		break;
1365 	default:
1366 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1367 		return -EINVAL;
1368 	}
1369 
1370 	return result;
1371 }
1372 
1373 /**
1374  * ubi_mtd_param_parse - parse the 'mtd=' UBI parameter.
1375  * @val: the parameter value to parse
1376  * @kp: not used
1377  *
1378  * This function returns zero in case of success and a negative error code in
1379  * case of error.
1380  */
1381 static int ubi_mtd_param_parse(const char *val, const struct kernel_param *kp)
1382 {
1383 	int i, len;
1384 	struct mtd_dev_param *p;
1385 	char buf[MTD_PARAM_LEN_MAX];
1386 	char *pbuf = &buf[0];
1387 	char *tokens[MTD_PARAM_MAX_COUNT], *token;
1388 
1389 	if (!val)
1390 		return -EINVAL;
1391 
1392 	if (mtd_devs == UBI_MAX_DEVICES) {
1393 		pr_err("UBI error: too many parameters, max. is %d\n",
1394 		       UBI_MAX_DEVICES);
1395 		return -EINVAL;
1396 	}
1397 
1398 	len = strnlen(val, MTD_PARAM_LEN_MAX);
1399 	if (len == MTD_PARAM_LEN_MAX) {
1400 		pr_err("UBI error: parameter \"%s\" is too long, max. is %d\n",
1401 		       val, MTD_PARAM_LEN_MAX);
1402 		return -EINVAL;
1403 	}
1404 
1405 	if (len == 0) {
1406 		pr_warn("UBI warning: empty 'mtd=' parameter - ignored\n");
1407 		return 0;
1408 	}
1409 
1410 	strcpy(buf, val);
1411 
1412 	/* Get rid of the final newline */
1413 	if (buf[len - 1] == '\n')
1414 		buf[len - 1] = '\0';
1415 
1416 	for (i = 0; i < MTD_PARAM_MAX_COUNT; i++)
1417 		tokens[i] = strsep(&pbuf, ",");
1418 
1419 	if (pbuf) {
1420 		pr_err("UBI error: too many arguments at \"%s\"\n", val);
1421 		return -EINVAL;
1422 	}
1423 
1424 	p = &mtd_dev_param[mtd_devs];
1425 	strcpy(&p->name[0], tokens[0]);
1426 
1427 	token = tokens[1];
1428 	if (token) {
1429 		p->vid_hdr_offs = bytes_str_to_int(token);
1430 
1431 		if (p->vid_hdr_offs < 0)
1432 			return p->vid_hdr_offs;
1433 	}
1434 
1435 	token = tokens[2];
1436 	if (token) {
1437 		int err = kstrtoint(token, 10, &p->max_beb_per1024);
1438 
1439 		if (err) {
1440 			pr_err("UBI error: bad value for max_beb_per1024 parameter: %s\n",
1441 			       token);
1442 			return -EINVAL;
1443 		}
1444 	}
1445 
1446 	token = tokens[3];
1447 	if (token) {
1448 		int err = kstrtoint(token, 10, &p->ubi_num);
1449 
1450 		if (err) {
1451 			pr_err("UBI error: bad value for ubi_num parameter: %s\n",
1452 			       token);
1453 			return -EINVAL;
1454 		}
1455 	} else
1456 		p->ubi_num = UBI_DEV_NUM_AUTO;
1457 
1458 	token = tokens[4];
1459 	if (token) {
1460 		int err = kstrtoint(token, 10, &p->enable_fm);
1461 
1462 		if (err) {
1463 			pr_err("UBI error: bad value for enable_fm parameter: %s\n",
1464 				token);
1465 			return -EINVAL;
1466 		}
1467 	} else
1468 		p->enable_fm = 0;
1469 
1470 	mtd_devs += 1;
1471 	return 0;
1472 }
1473 
1474 module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 0400);
1475 MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024[,ubi_num]]].\n"
1476 		      "Multiple \"mtd\" parameters may be specified.\n"
1477 		      "MTD devices may be specified by their number, name, or path to the MTD character device node.\n"
1478 		      "Optional \"vid_hdr_offs\" parameter specifies UBI VID header position to be used by UBI. (default value if 0)\n"
1479 		      "Optional \"max_beb_per1024\" parameter specifies the maximum expected bad eraseblock per 1024 eraseblocks. (default value ("
1480 		      __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0)\n"
1481 		      "Optional \"ubi_num\" parameter specifies UBI device number which have to be assigned to the newly created UBI device (assigned automatically by default)\n"
1482 		      "Optional \"enable_fm\" parameter determines whether to enable fastmap during attach. If the value is non-zero, fastmap is enabled. Default value is 0.\n"
1483 		      "\n"
1484 		      "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
1485 		      "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"
1486 		      "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"
1487 		      "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"
1488 		      "example 5: mtd=1,0,0,5 mtd=2,0,0,6,1 - attach MTD device /dev/mtd1 to UBI 5 and disable fastmap; attach MTD device /dev/mtd2 to UBI 6 and enable fastmap.(only works when fastmap is enabled and fm_autoconvert=Y).\n"
1489 		      "\t(e.g. if the NAND *chipset* has 4096 PEB, 100 will be reserved for this UBI device).");
1490 #ifdef CONFIG_MTD_UBI_FASTMAP
1491 module_param(fm_autoconvert, bool, 0644);
1492 MODULE_PARM_DESC(fm_autoconvert, "Set this parameter to enable fastmap automatically on images without a fastmap.");
1493 module_param(fm_debug, bool, 0);
1494 MODULE_PARM_DESC(fm_debug, "Set this parameter to enable fastmap debugging by default. Warning, this will make fastmap slow!");
1495 #endif
1496 MODULE_VERSION(__stringify(UBI_VERSION));
1497 MODULE_DESCRIPTION("UBI - Unsorted Block Images");
1498 MODULE_AUTHOR("Artem Bityutskiy");
1499 MODULE_LICENSE("GPL");
1500