xref: /linux/drivers/mtd/ubi/build.c (revision a460513ed4b6994bfeb7bd86f72853140bc1ac12)
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 4
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  */
57 struct mtd_dev_param {
58 	char name[MTD_PARAM_LEN_MAX];
59 	int ubi_num;
60 	int vid_hdr_offs;
61 	int max_beb_per1024;
62 };
63 
64 /* Numbers of elements set in the @mtd_dev_param array */
65 static int mtd_devs;
66 
67 /* MTD devices specification parameters */
68 static struct mtd_dev_param mtd_dev_param[UBI_MAX_DEVICES];
69 #ifdef CONFIG_MTD_UBI_FASTMAP
70 /* UBI module parameter to enable fastmap automatically on non-fastmap images */
71 static bool fm_autoconvert;
72 static bool fm_debug;
73 #endif
74 
75 /* Slab cache for wear-leveling entries */
76 struct kmem_cache *ubi_wl_entry_slab;
77 
78 /* UBI control character device */
79 static struct miscdevice ubi_ctrl_cdev = {
80 	.minor = MISC_DYNAMIC_MINOR,
81 	.name = "ubi_ctrl",
82 	.fops = &ubi_ctrl_cdev_operations,
83 };
84 
85 /* All UBI devices in system */
86 static struct ubi_device *ubi_devices[UBI_MAX_DEVICES];
87 
88 /* Serializes UBI devices creations and removals */
89 DEFINE_MUTEX(ubi_devices_mutex);
90 
91 /* Protects @ubi_devices and @ubi->ref_count */
92 static DEFINE_SPINLOCK(ubi_devices_lock);
93 
94 /* "Show" method for files in '/<sysfs>/class/ubi/' */
95 /* UBI version attribute ('/<sysfs>/class/ubi/version') */
96 static ssize_t version_show(struct class *class, struct class_attribute *attr,
97 			    char *buf)
98 {
99 	return sprintf(buf, "%d\n", UBI_VERSION);
100 }
101 static CLASS_ATTR_RO(version);
102 
103 static struct attribute *ubi_class_attrs[] = {
104 	&class_attr_version.attr,
105 	NULL,
106 };
107 ATTRIBUTE_GROUPS(ubi_class);
108 
109 /* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
110 struct class ubi_class = {
111 	.name		= UBI_NAME_STR,
112 	.owner		= THIS_MODULE,
113 	.class_groups	= ubi_class_groups,
114 };
115 
116 static ssize_t dev_attribute_show(struct device *dev,
117 				  struct device_attribute *attr, char *buf);
118 
119 /* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
120 static struct device_attribute dev_eraseblock_size =
121 	__ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
122 static struct device_attribute dev_avail_eraseblocks =
123 	__ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
124 static struct device_attribute dev_total_eraseblocks =
125 	__ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
126 static struct device_attribute dev_volumes_count =
127 	__ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
128 static struct device_attribute dev_max_ec =
129 	__ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
130 static struct device_attribute dev_reserved_for_bad =
131 	__ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
132 static struct device_attribute dev_bad_peb_count =
133 	__ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
134 static struct device_attribute dev_max_vol_count =
135 	__ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
136 static struct device_attribute dev_min_io_size =
137 	__ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
138 static struct device_attribute dev_bgt_enabled =
139 	__ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);
140 static struct device_attribute dev_mtd_num =
141 	__ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
142 static struct device_attribute dev_ro_mode =
143 	__ATTR(ro_mode, S_IRUGO, dev_attribute_show, NULL);
144 
145 /**
146  * ubi_volume_notify - send a volume change notification.
147  * @ubi: UBI device description object
148  * @vol: volume description object of the changed volume
149  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
150  *
151  * This is a helper function which notifies all subscribers about a volume
152  * change event (creation, removal, re-sizing, re-naming, updating). Returns
153  * zero in case of success and a negative error code in case of failure.
154  */
155 int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
156 {
157 	int ret;
158 	struct ubi_notification nt;
159 
160 	ubi_do_get_device_info(ubi, &nt.di);
161 	ubi_do_get_volume_info(ubi, vol, &nt.vi);
162 
163 	switch (ntype) {
164 	case UBI_VOLUME_ADDED:
165 	case UBI_VOLUME_REMOVED:
166 	case UBI_VOLUME_RESIZED:
167 	case UBI_VOLUME_RENAMED:
168 		ret = ubi_update_fastmap(ubi);
169 		if (ret)
170 			ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
171 	}
172 
173 	return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
174 }
175 
176 /**
177  * ubi_notify_all - send a notification to all volumes.
178  * @ubi: UBI device description object
179  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
180  * @nb: the notifier to call
181  *
182  * This function walks all volumes of UBI device @ubi and sends the @ntype
183  * notification for each volume. If @nb is %NULL, then all registered notifiers
184  * are called, otherwise only the @nb notifier is called. Returns the number of
185  * sent notifications.
186  */
187 int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
188 {
189 	struct ubi_notification nt;
190 	int i, count = 0;
191 
192 	ubi_do_get_device_info(ubi, &nt.di);
193 
194 	mutex_lock(&ubi->device_mutex);
195 	for (i = 0; i < ubi->vtbl_slots; i++) {
196 		/*
197 		 * Since the @ubi->device is locked, and we are not going to
198 		 * change @ubi->volumes, we do not have to lock
199 		 * @ubi->volumes_lock.
200 		 */
201 		if (!ubi->volumes[i])
202 			continue;
203 
204 		ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
205 		if (nb)
206 			nb->notifier_call(nb, ntype, &nt);
207 		else
208 			blocking_notifier_call_chain(&ubi_notifiers, ntype,
209 						     &nt);
210 		count += 1;
211 	}
212 	mutex_unlock(&ubi->device_mutex);
213 
214 	return count;
215 }
216 
217 /**
218  * ubi_enumerate_volumes - send "add" notification for all existing volumes.
219  * @nb: the notifier to call
220  *
221  * This function walks all UBI devices and volumes and sends the
222  * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
223  * registered notifiers are called, otherwise only the @nb notifier is called.
224  * Returns the number of sent notifications.
225  */
226 int ubi_enumerate_volumes(struct notifier_block *nb)
227 {
228 	int i, count = 0;
229 
230 	/*
231 	 * Since the @ubi_devices_mutex is locked, and we are not going to
232 	 * change @ubi_devices, we do not have to lock @ubi_devices_lock.
233 	 */
234 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
235 		struct ubi_device *ubi = ubi_devices[i];
236 
237 		if (!ubi)
238 			continue;
239 		count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
240 	}
241 
242 	return count;
243 }
244 
245 /**
246  * ubi_get_device - get UBI device.
247  * @ubi_num: UBI device number
248  *
249  * This function returns UBI device description object for UBI device number
250  * @ubi_num, or %NULL if the device does not exist. This function increases the
251  * device reference count to prevent removal of the device. In other words, the
252  * device cannot be removed if its reference count is not zero.
253  */
254 struct ubi_device *ubi_get_device(int ubi_num)
255 {
256 	struct ubi_device *ubi;
257 
258 	spin_lock(&ubi_devices_lock);
259 	ubi = ubi_devices[ubi_num];
260 	if (ubi) {
261 		ubi_assert(ubi->ref_count >= 0);
262 		ubi->ref_count += 1;
263 		get_device(&ubi->dev);
264 	}
265 	spin_unlock(&ubi_devices_lock);
266 
267 	return ubi;
268 }
269 
270 /**
271  * ubi_put_device - drop an UBI device reference.
272  * @ubi: UBI device description object
273  */
274 void ubi_put_device(struct ubi_device *ubi)
275 {
276 	spin_lock(&ubi_devices_lock);
277 	ubi->ref_count -= 1;
278 	put_device(&ubi->dev);
279 	spin_unlock(&ubi_devices_lock);
280 }
281 
282 /**
283  * ubi_get_by_major - get UBI device by character device major number.
284  * @major: major number
285  *
286  * This function is similar to 'ubi_get_device()', but it searches the device
287  * by its major number.
288  */
289 struct ubi_device *ubi_get_by_major(int major)
290 {
291 	int i;
292 	struct ubi_device *ubi;
293 
294 	spin_lock(&ubi_devices_lock);
295 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
296 		ubi = ubi_devices[i];
297 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
298 			ubi_assert(ubi->ref_count >= 0);
299 			ubi->ref_count += 1;
300 			get_device(&ubi->dev);
301 			spin_unlock(&ubi_devices_lock);
302 			return ubi;
303 		}
304 	}
305 	spin_unlock(&ubi_devices_lock);
306 
307 	return NULL;
308 }
309 
310 /**
311  * ubi_major2num - get UBI device number by character device major number.
312  * @major: major number
313  *
314  * This function searches UBI device number object by its major number. If UBI
315  * device was not found, this function returns -ENODEV, otherwise the UBI device
316  * number is returned.
317  */
318 int ubi_major2num(int major)
319 {
320 	int i, ubi_num = -ENODEV;
321 
322 	spin_lock(&ubi_devices_lock);
323 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
324 		struct ubi_device *ubi = ubi_devices[i];
325 
326 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
327 			ubi_num = ubi->ubi_num;
328 			break;
329 		}
330 	}
331 	spin_unlock(&ubi_devices_lock);
332 
333 	return ubi_num;
334 }
335 
336 /* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
337 static ssize_t dev_attribute_show(struct device *dev,
338 				  struct device_attribute *attr, char *buf)
339 {
340 	ssize_t ret;
341 	struct ubi_device *ubi;
342 
343 	/*
344 	 * The below code looks weird, but it actually makes sense. We get the
345 	 * UBI device reference from the contained 'struct ubi_device'. But it
346 	 * is unclear if the device was removed or not yet. Indeed, if the
347 	 * device was removed before we increased its reference count,
348 	 * 'ubi_get_device()' will return -ENODEV and we fail.
349 	 *
350 	 * Remember, 'struct ubi_device' is freed in the release function, so
351 	 * we still can use 'ubi->ubi_num'.
352 	 */
353 	ubi = container_of(dev, struct ubi_device, dev);
354 	ubi = ubi_get_device(ubi->ubi_num);
355 	if (!ubi)
356 		return -ENODEV;
357 
358 	if (attr == &dev_eraseblock_size)
359 		ret = sprintf(buf, "%d\n", ubi->leb_size);
360 	else if (attr == &dev_avail_eraseblocks)
361 		ret = sprintf(buf, "%d\n", ubi->avail_pebs);
362 	else if (attr == &dev_total_eraseblocks)
363 		ret = sprintf(buf, "%d\n", ubi->good_peb_count);
364 	else if (attr == &dev_volumes_count)
365 		ret = sprintf(buf, "%d\n", ubi->vol_count - UBI_INT_VOL_COUNT);
366 	else if (attr == &dev_max_ec)
367 		ret = sprintf(buf, "%d\n", ubi->max_ec);
368 	else if (attr == &dev_reserved_for_bad)
369 		ret = sprintf(buf, "%d\n", ubi->beb_rsvd_pebs);
370 	else if (attr == &dev_bad_peb_count)
371 		ret = sprintf(buf, "%d\n", ubi->bad_peb_count);
372 	else if (attr == &dev_max_vol_count)
373 		ret = sprintf(buf, "%d\n", ubi->vtbl_slots);
374 	else if (attr == &dev_min_io_size)
375 		ret = sprintf(buf, "%d\n", ubi->min_io_size);
376 	else if (attr == &dev_bgt_enabled)
377 		ret = sprintf(buf, "%d\n", ubi->thread_enabled);
378 	else if (attr == &dev_mtd_num)
379 		ret = sprintf(buf, "%d\n", ubi->mtd->index);
380 	else if (attr == &dev_ro_mode)
381 		ret = sprintf(buf, "%d\n", ubi->ro_mode);
382 	else
383 		ret = -EINVAL;
384 
385 	ubi_put_device(ubi);
386 	return ret;
387 }
388 
389 static struct attribute *ubi_dev_attrs[] = {
390 	&dev_eraseblock_size.attr,
391 	&dev_avail_eraseblocks.attr,
392 	&dev_total_eraseblocks.attr,
393 	&dev_volumes_count.attr,
394 	&dev_max_ec.attr,
395 	&dev_reserved_for_bad.attr,
396 	&dev_bad_peb_count.attr,
397 	&dev_max_vol_count.attr,
398 	&dev_min_io_size.attr,
399 	&dev_bgt_enabled.attr,
400 	&dev_mtd_num.attr,
401 	&dev_ro_mode.attr,
402 	NULL
403 };
404 ATTRIBUTE_GROUPS(ubi_dev);
405 
406 static void dev_release(struct device *dev)
407 {
408 	struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);
409 
410 	kfree(ubi);
411 }
412 
413 /**
414  * kill_volumes - destroy all user volumes.
415  * @ubi: UBI device description object
416  */
417 static void kill_volumes(struct ubi_device *ubi)
418 {
419 	int i;
420 
421 	for (i = 0; i < ubi->vtbl_slots; i++)
422 		if (ubi->volumes[i])
423 			ubi_free_volume(ubi, ubi->volumes[i]);
424 }
425 
426 /**
427  * uif_init - initialize user interfaces for an UBI device.
428  * @ubi: UBI device description object
429  *
430  * This function initializes various user interfaces for an UBI device. If the
431  * initialization fails at an early stage, this function frees all the
432  * resources it allocated, returns an error.
433  *
434  * This function returns zero in case of success and a negative error code in
435  * case of failure.
436  */
437 static int uif_init(struct ubi_device *ubi)
438 {
439 	int i, err;
440 	dev_t dev;
441 
442 	sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);
443 
444 	/*
445 	 * Major numbers for the UBI character devices are allocated
446 	 * dynamically. Major numbers of volume character devices are
447 	 * equivalent to ones of the corresponding UBI character device. Minor
448 	 * numbers of UBI character devices are 0, while minor numbers of
449 	 * volume character devices start from 1. Thus, we allocate one major
450 	 * number and ubi->vtbl_slots + 1 minor numbers.
451 	 */
452 	err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
453 	if (err) {
454 		ubi_err(ubi, "cannot register UBI character devices");
455 		return err;
456 	}
457 
458 	ubi->dev.devt = dev;
459 
460 	ubi_assert(MINOR(dev) == 0);
461 	cdev_init(&ubi->cdev, &ubi_cdev_operations);
462 	dbg_gen("%s major is %u", ubi->ubi_name, MAJOR(dev));
463 	ubi->cdev.owner = THIS_MODULE;
464 
465 	dev_set_name(&ubi->dev, UBI_NAME_STR "%d", ubi->ubi_num);
466 	err = cdev_device_add(&ubi->cdev, &ubi->dev);
467 	if (err)
468 		goto out_unreg;
469 
470 	for (i = 0; i < ubi->vtbl_slots; i++)
471 		if (ubi->volumes[i]) {
472 			err = ubi_add_volume(ubi, ubi->volumes[i]);
473 			if (err) {
474 				ubi_err(ubi, "cannot add volume %d", i);
475 				goto out_volumes;
476 			}
477 		}
478 
479 	return 0;
480 
481 out_volumes:
482 	kill_volumes(ubi);
483 	cdev_device_del(&ubi->cdev, &ubi->dev);
484 out_unreg:
485 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
486 	ubi_err(ubi, "cannot initialize UBI %s, error %d",
487 		ubi->ubi_name, err);
488 	return err;
489 }
490 
491 /**
492  * uif_close - close user interfaces for an UBI device.
493  * @ubi: UBI device description object
494  *
495  * Note, since this function un-registers UBI volume device objects (@vol->dev),
496  * the memory allocated voe the volumes is freed as well (in the release
497  * function).
498  */
499 static void uif_close(struct ubi_device *ubi)
500 {
501 	kill_volumes(ubi);
502 	cdev_device_del(&ubi->cdev, &ubi->dev);
503 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
504 }
505 
506 /**
507  * ubi_free_volumes_from - free volumes from specific index.
508  * @ubi: UBI device description object
509  * @from: the start index used for volume free.
510  */
511 static void ubi_free_volumes_from(struct ubi_device *ubi, int from)
512 {
513 	int i;
514 
515 	for (i = from; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
516 		if (!ubi->volumes[i])
517 			continue;
518 		ubi_eba_replace_table(ubi->volumes[i], NULL);
519 		ubi_fastmap_destroy_checkmap(ubi->volumes[i]);
520 		kfree(ubi->volumes[i]);
521 		ubi->volumes[i] = NULL;
522 	}
523 }
524 
525 /**
526  * ubi_free_all_volumes - free all volumes.
527  * @ubi: UBI device description object
528  */
529 void ubi_free_all_volumes(struct ubi_device *ubi)
530 {
531 	ubi_free_volumes_from(ubi, 0);
532 }
533 
534 /**
535  * ubi_free_internal_volumes - free internal volumes.
536  * @ubi: UBI device description object
537  */
538 void ubi_free_internal_volumes(struct ubi_device *ubi)
539 {
540 	ubi_free_volumes_from(ubi, ubi->vtbl_slots);
541 }
542 
543 static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
544 {
545 	int limit, device_pebs;
546 	uint64_t device_size;
547 
548 	if (!max_beb_per1024) {
549 		/*
550 		 * Since max_beb_per1024 has not been set by the user in either
551 		 * the cmdline or Kconfig, use mtd_max_bad_blocks to set the
552 		 * limit if it is supported by the device.
553 		 */
554 		limit = mtd_max_bad_blocks(ubi->mtd, 0, ubi->mtd->size);
555 		if (limit < 0)
556 			return 0;
557 		return limit;
558 	}
559 
560 	/*
561 	 * Here we are using size of the entire flash chip and
562 	 * not just the MTD partition size because the maximum
563 	 * number of bad eraseblocks is a percentage of the
564 	 * whole device and bad eraseblocks are not fairly
565 	 * distributed over the flash chip. So the worst case
566 	 * is that all the bad eraseblocks of the chip are in
567 	 * the MTD partition we are attaching (ubi->mtd).
568 	 */
569 	device_size = mtd_get_device_size(ubi->mtd);
570 	device_pebs = mtd_div_by_eb(device_size, ubi->mtd);
571 	limit = mult_frac(device_pebs, max_beb_per1024, 1024);
572 
573 	/* Round it up */
574 	if (mult_frac(limit, 1024, max_beb_per1024) < device_pebs)
575 		limit += 1;
576 
577 	return limit;
578 }
579 
580 /**
581  * io_init - initialize I/O sub-system for a given UBI device.
582  * @ubi: UBI device description object
583  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
584  *
585  * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
586  * assumed:
587  *   o EC header is always at offset zero - this cannot be changed;
588  *   o VID header starts just after the EC header at the closest address
589  *     aligned to @io->hdrs_min_io_size;
590  *   o data starts just after the VID header at the closest address aligned to
591  *     @io->min_io_size
592  *
593  * This function returns zero in case of success and a negative error code in
594  * case of failure.
595  */
596 static int io_init(struct ubi_device *ubi, int max_beb_per1024)
597 {
598 	dbg_gen("sizeof(struct ubi_ainf_peb) %zu", sizeof(struct ubi_ainf_peb));
599 	dbg_gen("sizeof(struct ubi_wl_entry) %zu", sizeof(struct ubi_wl_entry));
600 
601 	if (ubi->mtd->numeraseregions != 0) {
602 		/*
603 		 * Some flashes have several erase regions. Different regions
604 		 * may have different eraseblock size and other
605 		 * characteristics. It looks like mostly multi-region flashes
606 		 * have one "main" region and one or more small regions to
607 		 * store boot loader code or boot parameters or whatever. I
608 		 * guess we should just pick the largest region. But this is
609 		 * not implemented.
610 		 */
611 		ubi_err(ubi, "multiple regions, not implemented");
612 		return -EINVAL;
613 	}
614 
615 	if (ubi->vid_hdr_offset < 0)
616 		return -EINVAL;
617 
618 	/*
619 	 * Note, in this implementation we support MTD devices with 0x7FFFFFFF
620 	 * physical eraseblocks maximum.
621 	 */
622 
623 	ubi->peb_size   = ubi->mtd->erasesize;
624 	ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
625 	ubi->flash_size = ubi->mtd->size;
626 
627 	if (mtd_can_have_bb(ubi->mtd)) {
628 		ubi->bad_allowed = 1;
629 		ubi->bad_peb_limit = get_bad_peb_limit(ubi, max_beb_per1024);
630 	}
631 
632 	if (ubi->mtd->type == MTD_NORFLASH)
633 		ubi->nor_flash = 1;
634 
635 	ubi->min_io_size = ubi->mtd->writesize;
636 	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
637 
638 	/*
639 	 * Make sure minimal I/O unit is power of 2. Note, there is no
640 	 * fundamental reason for this assumption. It is just an optimization
641 	 * which allows us to avoid costly division operations.
642 	 */
643 	if (!is_power_of_2(ubi->min_io_size)) {
644 		ubi_err(ubi, "min. I/O unit (%d) is not power of 2",
645 			ubi->min_io_size);
646 		return -EINVAL;
647 	}
648 
649 	ubi_assert(ubi->hdrs_min_io_size > 0);
650 	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
651 	ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
652 
653 	ubi->max_write_size = ubi->mtd->writebufsize;
654 	/*
655 	 * Maximum write size has to be greater or equivalent to min. I/O
656 	 * size, and be multiple of min. I/O size.
657 	 */
658 	if (ubi->max_write_size < ubi->min_io_size ||
659 	    ubi->max_write_size % ubi->min_io_size ||
660 	    !is_power_of_2(ubi->max_write_size)) {
661 		ubi_err(ubi, "bad write buffer size %d for %d min. I/O unit",
662 			ubi->max_write_size, ubi->min_io_size);
663 		return -EINVAL;
664 	}
665 
666 	/* Calculate default aligned sizes of EC and VID headers */
667 	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
668 	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
669 
670 	dbg_gen("min_io_size      %d", ubi->min_io_size);
671 	dbg_gen("max_write_size   %d", ubi->max_write_size);
672 	dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
673 	dbg_gen("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
674 	dbg_gen("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
675 
676 	if (ubi->vid_hdr_offset == 0)
677 		/* Default offset */
678 		ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
679 				      ubi->ec_hdr_alsize;
680 	else {
681 		ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
682 						~(ubi->hdrs_min_io_size - 1);
683 		ubi->vid_hdr_shift = ubi->vid_hdr_offset -
684 						ubi->vid_hdr_aloffset;
685 	}
686 
687 	/* Similar for the data offset */
688 	ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
689 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
690 
691 	dbg_gen("vid_hdr_offset   %d", ubi->vid_hdr_offset);
692 	dbg_gen("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
693 	dbg_gen("vid_hdr_shift    %d", ubi->vid_hdr_shift);
694 	dbg_gen("leb_start        %d", ubi->leb_start);
695 
696 	/* The shift must be aligned to 32-bit boundary */
697 	if (ubi->vid_hdr_shift % 4) {
698 		ubi_err(ubi, "unaligned VID header shift %d",
699 			ubi->vid_hdr_shift);
700 		return -EINVAL;
701 	}
702 
703 	/* Check sanity */
704 	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
705 	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
706 	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
707 	    ubi->leb_start & (ubi->min_io_size - 1)) {
708 		ubi_err(ubi, "bad VID header (%d) or data offsets (%d)",
709 			ubi->vid_hdr_offset, ubi->leb_start);
710 		return -EINVAL;
711 	}
712 
713 	/*
714 	 * Set maximum amount of physical erroneous eraseblocks to be 10%.
715 	 * Erroneous PEB are those which have read errors.
716 	 */
717 	ubi->max_erroneous = ubi->peb_count / 10;
718 	if (ubi->max_erroneous < 16)
719 		ubi->max_erroneous = 16;
720 	dbg_gen("max_erroneous    %d", ubi->max_erroneous);
721 
722 	/*
723 	 * It may happen that EC and VID headers are situated in one minimal
724 	 * I/O unit. In this case we can only accept this UBI image in
725 	 * read-only mode.
726 	 */
727 	if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
728 		ubi_warn(ubi, "EC and VID headers are in the same minimal I/O unit, switch to read-only mode");
729 		ubi->ro_mode = 1;
730 	}
731 
732 	ubi->leb_size = ubi->peb_size - ubi->leb_start;
733 
734 	if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
735 		ubi_msg(ubi, "MTD device %d is write-protected, attach in read-only mode",
736 			ubi->mtd->index);
737 		ubi->ro_mode = 1;
738 	}
739 
740 	/*
741 	 * Note, ideally, we have to initialize @ubi->bad_peb_count here. But
742 	 * unfortunately, MTD does not provide this information. We should loop
743 	 * over all physical eraseblocks and invoke mtd->block_is_bad() for
744 	 * each physical eraseblock. So, we leave @ubi->bad_peb_count
745 	 * uninitialized so far.
746 	 */
747 
748 	return 0;
749 }
750 
751 /**
752  * autoresize - re-size the volume which has the "auto-resize" flag set.
753  * @ubi: UBI device description object
754  * @vol_id: ID of the volume to re-size
755  *
756  * This function re-sizes the volume marked by the %UBI_VTBL_AUTORESIZE_FLG in
757  * the volume table to the largest possible size. See comments in ubi-header.h
758  * for more description of the flag. Returns zero in case of success and a
759  * negative error code in case of failure.
760  */
761 static int autoresize(struct ubi_device *ubi, int vol_id)
762 {
763 	struct ubi_volume_desc desc;
764 	struct ubi_volume *vol = ubi->volumes[vol_id];
765 	int err, old_reserved_pebs = vol->reserved_pebs;
766 
767 	if (ubi->ro_mode) {
768 		ubi_warn(ubi, "skip auto-resize because of R/O mode");
769 		return 0;
770 	}
771 
772 	/*
773 	 * Clear the auto-resize flag in the volume in-memory copy of the
774 	 * volume table, and 'ubi_resize_volume()' will propagate this change
775 	 * to the flash.
776 	 */
777 	ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;
778 
779 	if (ubi->avail_pebs == 0) {
780 		struct ubi_vtbl_record vtbl_rec;
781 
782 		/*
783 		 * No available PEBs to re-size the volume, clear the flag on
784 		 * flash and exit.
785 		 */
786 		vtbl_rec = ubi->vtbl[vol_id];
787 		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
788 		if (err)
789 			ubi_err(ubi, "cannot clean auto-resize flag for volume %d",
790 				vol_id);
791 	} else {
792 		desc.vol = vol;
793 		err = ubi_resize_volume(&desc,
794 					old_reserved_pebs + ubi->avail_pebs);
795 		if (err)
796 			ubi_err(ubi, "cannot auto-resize volume %d",
797 				vol_id);
798 	}
799 
800 	if (err)
801 		return err;
802 
803 	ubi_msg(ubi, "volume %d (\"%s\") re-sized from %d to %d LEBs",
804 		vol_id, vol->name, old_reserved_pebs, vol->reserved_pebs);
805 	return 0;
806 }
807 
808 /**
809  * ubi_attach_mtd_dev - attach an MTD device.
810  * @mtd: MTD device description object
811  * @ubi_num: number to assign to the new UBI device
812  * @vid_hdr_offset: VID header offset
813  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
814  *
815  * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
816  * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
817  * which case this function finds a vacant device number and assigns it
818  * automatically. Returns the new UBI device number in case of success and a
819  * negative error code in case of failure.
820  *
821  * Note, the invocations of this function has to be serialized by the
822  * @ubi_devices_mutex.
823  */
824 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
825 		       int vid_hdr_offset, int max_beb_per1024)
826 {
827 	struct ubi_device *ubi;
828 	int i, err;
829 
830 	if (max_beb_per1024 < 0 || max_beb_per1024 > MAX_MTD_UBI_BEB_LIMIT)
831 		return -EINVAL;
832 
833 	if (!max_beb_per1024)
834 		max_beb_per1024 = CONFIG_MTD_UBI_BEB_LIMIT;
835 
836 	/*
837 	 * Check if we already have the same MTD device attached.
838 	 *
839 	 * Note, this function assumes that UBI devices creations and deletions
840 	 * are serialized, so it does not take the &ubi_devices_lock.
841 	 */
842 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
843 		ubi = ubi_devices[i];
844 		if (ubi && mtd->index == ubi->mtd->index) {
845 			pr_err("ubi: mtd%d is already attached to ubi%d\n",
846 				mtd->index, i);
847 			return -EEXIST;
848 		}
849 	}
850 
851 	/*
852 	 * Make sure this MTD device is not emulated on top of an UBI volume
853 	 * already. Well, generally this recursion works fine, but there are
854 	 * different problems like the UBI module takes a reference to itself
855 	 * by attaching (and thus, opening) the emulated MTD device. This
856 	 * results in inability to unload the module. And in general it makes
857 	 * no sense to attach emulated MTD devices, so we prohibit this.
858 	 */
859 	if (mtd->type == MTD_UBIVOLUME) {
860 		pr_err("ubi: refuse attaching mtd%d - it is already emulated on top of UBI\n",
861 			mtd->index);
862 		return -EINVAL;
863 	}
864 
865 	/*
866 	 * Both UBI and UBIFS have been designed for SLC NAND and NOR flashes.
867 	 * MLC NAND is different and needs special care, otherwise UBI or UBIFS
868 	 * will die soon and you will lose all your data.
869 	 * Relax this rule if the partition we're attaching to operates in SLC
870 	 * mode.
871 	 */
872 	if (mtd->type == MTD_MLCNANDFLASH &&
873 	    !(mtd->flags & MTD_SLC_ON_MLC_EMULATION)) {
874 		pr_err("ubi: refuse attaching mtd%d - MLC NAND is not supported\n",
875 			mtd->index);
876 		return -EINVAL;
877 	}
878 
879 	if (ubi_num == UBI_DEV_NUM_AUTO) {
880 		/* Search for an empty slot in the @ubi_devices array */
881 		for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
882 			if (!ubi_devices[ubi_num])
883 				break;
884 		if (ubi_num == UBI_MAX_DEVICES) {
885 			pr_err("ubi: only %d UBI devices may be created\n",
886 				UBI_MAX_DEVICES);
887 			return -ENFILE;
888 		}
889 	} else {
890 		if (ubi_num >= UBI_MAX_DEVICES)
891 			return -EINVAL;
892 
893 		/* Make sure ubi_num is not busy */
894 		if (ubi_devices[ubi_num]) {
895 			pr_err("ubi: ubi%i already exists\n", ubi_num);
896 			return -EEXIST;
897 		}
898 	}
899 
900 	ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
901 	if (!ubi)
902 		return -ENOMEM;
903 
904 	device_initialize(&ubi->dev);
905 	ubi->dev.release = dev_release;
906 	ubi->dev.class = &ubi_class;
907 	ubi->dev.groups = ubi_dev_groups;
908 
909 	ubi->mtd = mtd;
910 	ubi->ubi_num = ubi_num;
911 	ubi->vid_hdr_offset = vid_hdr_offset;
912 	ubi->autoresize_vol_id = -1;
913 
914 #ifdef CONFIG_MTD_UBI_FASTMAP
915 	ubi->fm_pool.used = ubi->fm_pool.size = 0;
916 	ubi->fm_wl_pool.used = ubi->fm_wl_pool.size = 0;
917 
918 	/*
919 	 * fm_pool.max_size is 5% of the total number of PEBs but it's also
920 	 * between UBI_FM_MAX_POOL_SIZE and UBI_FM_MIN_POOL_SIZE.
921 	 */
922 	ubi->fm_pool.max_size = min(((int)mtd_div_by_eb(ubi->mtd->size,
923 		ubi->mtd) / 100) * 5, UBI_FM_MAX_POOL_SIZE);
924 	ubi->fm_pool.max_size = max(ubi->fm_pool.max_size,
925 		UBI_FM_MIN_POOL_SIZE);
926 
927 	ubi->fm_wl_pool.max_size = ubi->fm_pool.max_size / 2;
928 	ubi->fm_disabled = !fm_autoconvert;
929 	if (fm_debug)
930 		ubi_enable_dbg_chk_fastmap(ubi);
931 
932 	if (!ubi->fm_disabled && (int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd)
933 	    <= UBI_FM_MAX_START) {
934 		ubi_err(ubi, "More than %i PEBs are needed for fastmap, sorry.",
935 			UBI_FM_MAX_START);
936 		ubi->fm_disabled = 1;
937 	}
938 
939 	ubi_msg(ubi, "default fastmap pool size: %d", ubi->fm_pool.max_size);
940 	ubi_msg(ubi, "default fastmap WL pool size: %d",
941 		ubi->fm_wl_pool.max_size);
942 #else
943 	ubi->fm_disabled = 1;
944 #endif
945 	mutex_init(&ubi->buf_mutex);
946 	mutex_init(&ubi->ckvol_mutex);
947 	mutex_init(&ubi->device_mutex);
948 	spin_lock_init(&ubi->volumes_lock);
949 	init_rwsem(&ubi->fm_protect);
950 	init_rwsem(&ubi->fm_eba_sem);
951 
952 	ubi_msg(ubi, "attaching mtd%d", mtd->index);
953 
954 	err = io_init(ubi, max_beb_per1024);
955 	if (err)
956 		goto out_free;
957 
958 	err = -ENOMEM;
959 	ubi->peb_buf = vmalloc(ubi->peb_size);
960 	if (!ubi->peb_buf)
961 		goto out_free;
962 
963 #ifdef CONFIG_MTD_UBI_FASTMAP
964 	ubi->fm_size = ubi_calc_fm_size(ubi);
965 	ubi->fm_buf = vzalloc(ubi->fm_size);
966 	if (!ubi->fm_buf)
967 		goto out_free;
968 #endif
969 	err = ubi_attach(ubi, 0);
970 	if (err) {
971 		ubi_err(ubi, "failed to attach mtd%d, error %d",
972 			mtd->index, err);
973 		goto out_free;
974 	}
975 
976 	if (ubi->autoresize_vol_id != -1) {
977 		err = autoresize(ubi, ubi->autoresize_vol_id);
978 		if (err)
979 			goto out_detach;
980 	}
981 
982 	/* Make device "available" before it becomes accessible via sysfs */
983 	ubi_devices[ubi_num] = ubi;
984 
985 	err = uif_init(ubi);
986 	if (err)
987 		goto out_detach;
988 
989 	err = ubi_debugfs_init_dev(ubi);
990 	if (err)
991 		goto out_uif;
992 
993 	ubi->bgt_thread = kthread_create(ubi_thread, ubi, "%s", ubi->bgt_name);
994 	if (IS_ERR(ubi->bgt_thread)) {
995 		err = PTR_ERR(ubi->bgt_thread);
996 		ubi_err(ubi, "cannot spawn \"%s\", error %d",
997 			ubi->bgt_name, err);
998 		goto out_debugfs;
999 	}
1000 
1001 	ubi_msg(ubi, "attached mtd%d (name \"%s\", size %llu MiB)",
1002 		mtd->index, mtd->name, ubi->flash_size >> 20);
1003 	ubi_msg(ubi, "PEB size: %d bytes (%d KiB), LEB size: %d bytes",
1004 		ubi->peb_size, ubi->peb_size >> 10, ubi->leb_size);
1005 	ubi_msg(ubi, "min./max. I/O unit sizes: %d/%d, sub-page size %d",
1006 		ubi->min_io_size, ubi->max_write_size, ubi->hdrs_min_io_size);
1007 	ubi_msg(ubi, "VID header offset: %d (aligned %d), data offset: %d",
1008 		ubi->vid_hdr_offset, ubi->vid_hdr_aloffset, ubi->leb_start);
1009 	ubi_msg(ubi, "good PEBs: %d, bad PEBs: %d, corrupted PEBs: %d",
1010 		ubi->good_peb_count, ubi->bad_peb_count, ubi->corr_peb_count);
1011 	ubi_msg(ubi, "user volume: %d, internal volumes: %d, max. volumes count: %d",
1012 		ubi->vol_count - UBI_INT_VOL_COUNT, UBI_INT_VOL_COUNT,
1013 		ubi->vtbl_slots);
1014 	ubi_msg(ubi, "max/mean erase counter: %d/%d, WL threshold: %d, image sequence number: %u",
1015 		ubi->max_ec, ubi->mean_ec, CONFIG_MTD_UBI_WL_THRESHOLD,
1016 		ubi->image_seq);
1017 	ubi_msg(ubi, "available PEBs: %d, total reserved PEBs: %d, PEBs reserved for bad PEB handling: %d",
1018 		ubi->avail_pebs, ubi->rsvd_pebs, ubi->beb_rsvd_pebs);
1019 
1020 	/*
1021 	 * The below lock makes sure we do not race with 'ubi_thread()' which
1022 	 * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
1023 	 */
1024 	spin_lock(&ubi->wl_lock);
1025 	ubi->thread_enabled = 1;
1026 	wake_up_process(ubi->bgt_thread);
1027 	spin_unlock(&ubi->wl_lock);
1028 
1029 	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
1030 	return ubi_num;
1031 
1032 out_debugfs:
1033 	ubi_debugfs_exit_dev(ubi);
1034 out_uif:
1035 	uif_close(ubi);
1036 out_detach:
1037 	ubi_devices[ubi_num] = NULL;
1038 	ubi_wl_close(ubi);
1039 	ubi_free_all_volumes(ubi);
1040 	vfree(ubi->vtbl);
1041 out_free:
1042 	vfree(ubi->peb_buf);
1043 	vfree(ubi->fm_buf);
1044 	put_device(&ubi->dev);
1045 	return err;
1046 }
1047 
1048 /**
1049  * ubi_detach_mtd_dev - detach an MTD device.
1050  * @ubi_num: UBI device number to detach from
1051  * @anyway: detach MTD even if device reference count is not zero
1052  *
1053  * This function destroys an UBI device number @ubi_num and detaches the
1054  * underlying MTD device. Returns zero in case of success and %-EBUSY if the
1055  * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
1056  * exist.
1057  *
1058  * Note, the invocations of this function has to be serialized by the
1059  * @ubi_devices_mutex.
1060  */
1061 int ubi_detach_mtd_dev(int ubi_num, int anyway)
1062 {
1063 	struct ubi_device *ubi;
1064 
1065 	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
1066 		return -EINVAL;
1067 
1068 	ubi = ubi_get_device(ubi_num);
1069 	if (!ubi)
1070 		return -EINVAL;
1071 
1072 	spin_lock(&ubi_devices_lock);
1073 	put_device(&ubi->dev);
1074 	ubi->ref_count -= 1;
1075 	if (ubi->ref_count) {
1076 		if (!anyway) {
1077 			spin_unlock(&ubi_devices_lock);
1078 			return -EBUSY;
1079 		}
1080 		/* This may only happen if there is a bug */
1081 		ubi_err(ubi, "%s reference count %d, destroy anyway",
1082 			ubi->ubi_name, ubi->ref_count);
1083 	}
1084 	ubi_devices[ubi_num] = NULL;
1085 	spin_unlock(&ubi_devices_lock);
1086 
1087 	ubi_assert(ubi_num == ubi->ubi_num);
1088 	ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
1089 	ubi_msg(ubi, "detaching mtd%d", ubi->mtd->index);
1090 #ifdef CONFIG_MTD_UBI_FASTMAP
1091 	/* If we don't write a new fastmap at detach time we lose all
1092 	 * EC updates that have been made since the last written fastmap.
1093 	 * In case of fastmap debugging we omit the update to simulate an
1094 	 * unclean shutdown. */
1095 	if (!ubi_dbg_chk_fastmap(ubi))
1096 		ubi_update_fastmap(ubi);
1097 #endif
1098 	/*
1099 	 * Before freeing anything, we have to stop the background thread to
1100 	 * prevent it from doing anything on this device while we are freeing.
1101 	 */
1102 	if (ubi->bgt_thread)
1103 		kthread_stop(ubi->bgt_thread);
1104 
1105 #ifdef CONFIG_MTD_UBI_FASTMAP
1106 	cancel_work_sync(&ubi->fm_work);
1107 #endif
1108 	ubi_debugfs_exit_dev(ubi);
1109 	uif_close(ubi);
1110 
1111 	ubi_wl_close(ubi);
1112 	ubi_free_internal_volumes(ubi);
1113 	vfree(ubi->vtbl);
1114 	vfree(ubi->peb_buf);
1115 	vfree(ubi->fm_buf);
1116 	ubi_msg(ubi, "mtd%d is detached", ubi->mtd->index);
1117 	put_mtd_device(ubi->mtd);
1118 	put_device(&ubi->dev);
1119 	return 0;
1120 }
1121 
1122 /**
1123  * open_mtd_by_chdev - open an MTD device by its character device node path.
1124  * @mtd_dev: MTD character device node path
1125  *
1126  * This helper function opens an MTD device by its character node device path.
1127  * Returns MTD device description object in case of success and a negative
1128  * error code in case of failure.
1129  */
1130 static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
1131 {
1132 	int err, minor;
1133 	struct path path;
1134 	struct kstat stat;
1135 
1136 	/* Probably this is an MTD character device node path */
1137 	err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
1138 	if (err)
1139 		return ERR_PTR(err);
1140 
1141 	err = vfs_getattr(&path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
1142 	path_put(&path);
1143 	if (err)
1144 		return ERR_PTR(err);
1145 
1146 	/* MTD device number is defined by the major / minor numbers */
1147 	if (MAJOR(stat.rdev) != MTD_CHAR_MAJOR || !S_ISCHR(stat.mode))
1148 		return ERR_PTR(-EINVAL);
1149 
1150 	minor = MINOR(stat.rdev);
1151 
1152 	if (minor & 1)
1153 		/*
1154 		 * Just do not think the "/dev/mtdrX" devices support is need,
1155 		 * so do not support them to avoid doing extra work.
1156 		 */
1157 		return ERR_PTR(-EINVAL);
1158 
1159 	return get_mtd_device(NULL, minor / 2);
1160 }
1161 
1162 /**
1163  * open_mtd_device - open MTD device by name, character device path, or number.
1164  * @mtd_dev: name, character device node path, or MTD device device number
1165  *
1166  * This function tries to open and MTD device described by @mtd_dev string,
1167  * which is first treated as ASCII MTD device number, and if it is not true, it
1168  * is treated as MTD device name, and if that is also not true, it is treated
1169  * as MTD character device node path. Returns MTD device description object in
1170  * case of success and a negative error code in case of failure.
1171  */
1172 static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
1173 {
1174 	struct mtd_info *mtd;
1175 	int mtd_num;
1176 	char *endp;
1177 
1178 	mtd_num = simple_strtoul(mtd_dev, &endp, 0);
1179 	if (*endp != '\0' || mtd_dev == endp) {
1180 		/*
1181 		 * This does not look like an ASCII integer, probably this is
1182 		 * MTD device name.
1183 		 */
1184 		mtd = get_mtd_device_nm(mtd_dev);
1185 		if (PTR_ERR(mtd) == -ENODEV)
1186 			/* Probably this is an MTD character device node path */
1187 			mtd = open_mtd_by_chdev(mtd_dev);
1188 	} else
1189 		mtd = get_mtd_device(NULL, mtd_num);
1190 
1191 	return mtd;
1192 }
1193 
1194 static int __init ubi_init(void)
1195 {
1196 	int err, i, k;
1197 
1198 	/* Ensure that EC and VID headers have correct size */
1199 	BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
1200 	BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);
1201 
1202 	if (mtd_devs > UBI_MAX_DEVICES) {
1203 		pr_err("UBI error: too many MTD devices, maximum is %d\n",
1204 		       UBI_MAX_DEVICES);
1205 		return -EINVAL;
1206 	}
1207 
1208 	/* Create base sysfs directory and sysfs files */
1209 	err = class_register(&ubi_class);
1210 	if (err < 0)
1211 		return err;
1212 
1213 	err = misc_register(&ubi_ctrl_cdev);
1214 	if (err) {
1215 		pr_err("UBI error: cannot register device\n");
1216 		goto out;
1217 	}
1218 
1219 	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
1220 					      sizeof(struct ubi_wl_entry),
1221 					      0, 0, NULL);
1222 	if (!ubi_wl_entry_slab) {
1223 		err = -ENOMEM;
1224 		goto out_dev_unreg;
1225 	}
1226 
1227 	err = ubi_debugfs_init();
1228 	if (err)
1229 		goto out_slab;
1230 
1231 
1232 	/* Attach MTD devices */
1233 	for (i = 0; i < mtd_devs; i++) {
1234 		struct mtd_dev_param *p = &mtd_dev_param[i];
1235 		struct mtd_info *mtd;
1236 
1237 		cond_resched();
1238 
1239 		mtd = open_mtd_device(p->name);
1240 		if (IS_ERR(mtd)) {
1241 			err = PTR_ERR(mtd);
1242 			pr_err("UBI error: cannot open mtd %s, error %d\n",
1243 			       p->name, err);
1244 			/* See comment below re-ubi_is_module(). */
1245 			if (ubi_is_module())
1246 				goto out_detach;
1247 			continue;
1248 		}
1249 
1250 		mutex_lock(&ubi_devices_mutex);
1251 		err = ubi_attach_mtd_dev(mtd, p->ubi_num,
1252 					 p->vid_hdr_offs, p->max_beb_per1024);
1253 		mutex_unlock(&ubi_devices_mutex);
1254 		if (err < 0) {
1255 			pr_err("UBI error: cannot attach mtd%d\n",
1256 			       mtd->index);
1257 			put_mtd_device(mtd);
1258 
1259 			/*
1260 			 * Originally UBI stopped initializing on any error.
1261 			 * However, later on it was found out that this
1262 			 * behavior is not very good when UBI is compiled into
1263 			 * the kernel and the MTD devices to attach are passed
1264 			 * through the command line. Indeed, UBI failure
1265 			 * stopped whole boot sequence.
1266 			 *
1267 			 * To fix this, we changed the behavior for the
1268 			 * non-module case, but preserved the old behavior for
1269 			 * the module case, just for compatibility. This is a
1270 			 * little inconsistent, though.
1271 			 */
1272 			if (ubi_is_module())
1273 				goto out_detach;
1274 		}
1275 	}
1276 
1277 	err = ubiblock_init();
1278 	if (err) {
1279 		pr_err("UBI error: block: cannot initialize, error %d\n", err);
1280 
1281 		/* See comment above re-ubi_is_module(). */
1282 		if (ubi_is_module())
1283 			goto out_detach;
1284 	}
1285 
1286 	return 0;
1287 
1288 out_detach:
1289 	for (k = 0; k < i; k++)
1290 		if (ubi_devices[k]) {
1291 			mutex_lock(&ubi_devices_mutex);
1292 			ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
1293 			mutex_unlock(&ubi_devices_mutex);
1294 		}
1295 	ubi_debugfs_exit();
1296 out_slab:
1297 	kmem_cache_destroy(ubi_wl_entry_slab);
1298 out_dev_unreg:
1299 	misc_deregister(&ubi_ctrl_cdev);
1300 out:
1301 	class_unregister(&ubi_class);
1302 	pr_err("UBI error: cannot initialize UBI, error %d\n", err);
1303 	return err;
1304 }
1305 late_initcall(ubi_init);
1306 
1307 static void __exit ubi_exit(void)
1308 {
1309 	int i;
1310 
1311 	ubiblock_exit();
1312 
1313 	for (i = 0; i < UBI_MAX_DEVICES; i++)
1314 		if (ubi_devices[i]) {
1315 			mutex_lock(&ubi_devices_mutex);
1316 			ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
1317 			mutex_unlock(&ubi_devices_mutex);
1318 		}
1319 	ubi_debugfs_exit();
1320 	kmem_cache_destroy(ubi_wl_entry_slab);
1321 	misc_deregister(&ubi_ctrl_cdev);
1322 	class_unregister(&ubi_class);
1323 }
1324 module_exit(ubi_exit);
1325 
1326 /**
1327  * bytes_str_to_int - convert a number of bytes string into an integer.
1328  * @str: the string to convert
1329  *
1330  * This function returns positive resulting integer in case of success and a
1331  * negative error code in case of failure.
1332  */
1333 static int bytes_str_to_int(const char *str)
1334 {
1335 	char *endp;
1336 	unsigned long result;
1337 
1338 	result = simple_strtoul(str, &endp, 0);
1339 	if (str == endp || result >= INT_MAX) {
1340 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1341 		return -EINVAL;
1342 	}
1343 
1344 	switch (*endp) {
1345 	case 'G':
1346 		result *= 1024;
1347 		fallthrough;
1348 	case 'M':
1349 		result *= 1024;
1350 		fallthrough;
1351 	case 'K':
1352 		result *= 1024;
1353 	case '\0':
1354 		break;
1355 	default:
1356 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1357 		return -EINVAL;
1358 	}
1359 
1360 	return result;
1361 }
1362 
1363 /**
1364  * ubi_mtd_param_parse - parse the 'mtd=' UBI parameter.
1365  * @val: the parameter value to parse
1366  * @kp: not used
1367  *
1368  * This function returns zero in case of success and a negative error code in
1369  * case of error.
1370  */
1371 static int ubi_mtd_param_parse(const char *val, const struct kernel_param *kp)
1372 {
1373 	int i, len;
1374 	struct mtd_dev_param *p;
1375 	char buf[MTD_PARAM_LEN_MAX];
1376 	char *pbuf = &buf[0];
1377 	char *tokens[MTD_PARAM_MAX_COUNT], *token;
1378 
1379 	if (!val)
1380 		return -EINVAL;
1381 
1382 	if (mtd_devs == UBI_MAX_DEVICES) {
1383 		pr_err("UBI error: too many parameters, max. is %d\n",
1384 		       UBI_MAX_DEVICES);
1385 		return -EINVAL;
1386 	}
1387 
1388 	len = strnlen(val, MTD_PARAM_LEN_MAX);
1389 	if (len == MTD_PARAM_LEN_MAX) {
1390 		pr_err("UBI error: parameter \"%s\" is too long, max. is %d\n",
1391 		       val, MTD_PARAM_LEN_MAX);
1392 		return -EINVAL;
1393 	}
1394 
1395 	if (len == 0) {
1396 		pr_warn("UBI warning: empty 'mtd=' parameter - ignored\n");
1397 		return 0;
1398 	}
1399 
1400 	strcpy(buf, val);
1401 
1402 	/* Get rid of the final newline */
1403 	if (buf[len - 1] == '\n')
1404 		buf[len - 1] = '\0';
1405 
1406 	for (i = 0; i < MTD_PARAM_MAX_COUNT; i++)
1407 		tokens[i] = strsep(&pbuf, ",");
1408 
1409 	if (pbuf) {
1410 		pr_err("UBI error: too many arguments at \"%s\"\n", val);
1411 		return -EINVAL;
1412 	}
1413 
1414 	p = &mtd_dev_param[mtd_devs];
1415 	strcpy(&p->name[0], tokens[0]);
1416 
1417 	token = tokens[1];
1418 	if (token) {
1419 		p->vid_hdr_offs = bytes_str_to_int(token);
1420 
1421 		if (p->vid_hdr_offs < 0)
1422 			return p->vid_hdr_offs;
1423 	}
1424 
1425 	token = tokens[2];
1426 	if (token) {
1427 		int err = kstrtoint(token, 10, &p->max_beb_per1024);
1428 
1429 		if (err) {
1430 			pr_err("UBI error: bad value for max_beb_per1024 parameter: %s",
1431 			       token);
1432 			return -EINVAL;
1433 		}
1434 	}
1435 
1436 	token = tokens[3];
1437 	if (token) {
1438 		int err = kstrtoint(token, 10, &p->ubi_num);
1439 
1440 		if (err) {
1441 			pr_err("UBI error: bad value for ubi_num parameter: %s",
1442 			       token);
1443 			return -EINVAL;
1444 		}
1445 	} else
1446 		p->ubi_num = UBI_DEV_NUM_AUTO;
1447 
1448 	mtd_devs += 1;
1449 	return 0;
1450 }
1451 
1452 module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 0400);
1453 MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024[,ubi_num]]].\n"
1454 		      "Multiple \"mtd\" parameters may be specified.\n"
1455 		      "MTD devices may be specified by their number, name, or path to the MTD character device node.\n"
1456 		      "Optional \"vid_hdr_offs\" parameter specifies UBI VID header position to be used by UBI. (default value if 0)\n"
1457 		      "Optional \"max_beb_per1024\" parameter specifies the maximum expected bad eraseblock per 1024 eraseblocks. (default value ("
1458 		      __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0)\n"
1459 		      "Optional \"ubi_num\" parameter specifies UBI device number which have to be assigned to the newly created UBI device (assigned automatically by default)\n"
1460 		      "\n"
1461 		      "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
1462 		      "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"
1463 		      "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"
1464 		      "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"
1465 		      "\t(e.g. if the NAND *chipset* has 4096 PEB, 100 will be reserved for this UBI device).");
1466 #ifdef CONFIG_MTD_UBI_FASTMAP
1467 module_param(fm_autoconvert, bool, 0644);
1468 MODULE_PARM_DESC(fm_autoconvert, "Set this parameter to enable fastmap automatically on images without a fastmap.");
1469 module_param(fm_debug, bool, 0);
1470 MODULE_PARM_DESC(fm_debug, "Set this parameter to enable fastmap debugging by default. Warning, this will make fastmap slow!");
1471 #endif
1472 MODULE_VERSION(__stringify(UBI_VERSION));
1473 MODULE_DESCRIPTION("UBI - Unsorted Block Images");
1474 MODULE_AUTHOR("Artem Bityutskiy");
1475 MODULE_LICENSE("GPL");
1476