xref: /openbmc/linux/drivers/mtd/ubi/build.c (revision 4bb1eb3c)
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  * @vid_hdr_offs: VID header offset
54  * @max_beb_per1024: maximum expected number of bad PEBs per 1024 PEBs
55  */
56 struct mtd_dev_param {
57 	char name[MTD_PARAM_LEN_MAX];
58 	int ubi_num;
59 	int vid_hdr_offs;
60 	int max_beb_per1024;
61 };
62 
63 /* Numbers of elements set in the @mtd_dev_param array */
64 static int mtd_devs;
65 
66 /* MTD devices specification parameters */
67 static struct mtd_dev_param mtd_dev_param[UBI_MAX_DEVICES];
68 #ifdef CONFIG_MTD_UBI_FASTMAP
69 /* UBI module parameter to enable fastmap automatically on non-fastmap images */
70 static bool fm_autoconvert;
71 static bool fm_debug;
72 #endif
73 
74 /* Slab cache for wear-leveling entries */
75 struct kmem_cache *ubi_wl_entry_slab;
76 
77 /* UBI control character device */
78 static struct miscdevice ubi_ctrl_cdev = {
79 	.minor = MISC_DYNAMIC_MINOR,
80 	.name = "ubi_ctrl",
81 	.fops = &ubi_ctrl_cdev_operations,
82 };
83 
84 /* All UBI devices in system */
85 static struct ubi_device *ubi_devices[UBI_MAX_DEVICES];
86 
87 /* Serializes UBI devices creations and removals */
88 DEFINE_MUTEX(ubi_devices_mutex);
89 
90 /* Protects @ubi_devices and @ubi->ref_count */
91 static DEFINE_SPINLOCK(ubi_devices_lock);
92 
93 /* "Show" method for files in '/<sysfs>/class/ubi/' */
94 /* UBI version attribute ('/<sysfs>/class/ubi/version') */
95 static ssize_t version_show(struct class *class, struct class_attribute *attr,
96 			    char *buf)
97 {
98 	return sprintf(buf, "%d\n", UBI_VERSION);
99 }
100 static CLASS_ATTR_RO(version);
101 
102 static struct attribute *ubi_class_attrs[] = {
103 	&class_attr_version.attr,
104 	NULL,
105 };
106 ATTRIBUTE_GROUPS(ubi_class);
107 
108 /* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
109 struct class ubi_class = {
110 	.name		= UBI_NAME_STR,
111 	.owner		= THIS_MODULE,
112 	.class_groups	= ubi_class_groups,
113 };
114 
115 static ssize_t dev_attribute_show(struct device *dev,
116 				  struct device_attribute *attr, char *buf);
117 
118 /* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
119 static struct device_attribute dev_eraseblock_size =
120 	__ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
121 static struct device_attribute dev_avail_eraseblocks =
122 	__ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
123 static struct device_attribute dev_total_eraseblocks =
124 	__ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
125 static struct device_attribute dev_volumes_count =
126 	__ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
127 static struct device_attribute dev_max_ec =
128 	__ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
129 static struct device_attribute dev_reserved_for_bad =
130 	__ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
131 static struct device_attribute dev_bad_peb_count =
132 	__ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
133 static struct device_attribute dev_max_vol_count =
134 	__ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
135 static struct device_attribute dev_min_io_size =
136 	__ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
137 static struct device_attribute dev_bgt_enabled =
138 	__ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);
139 static struct device_attribute dev_mtd_num =
140 	__ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
141 static struct device_attribute dev_ro_mode =
142 	__ATTR(ro_mode, S_IRUGO, dev_attribute_show, NULL);
143 
144 /**
145  * ubi_volume_notify - send a volume change notification.
146  * @ubi: UBI device description object
147  * @vol: volume description object of the changed volume
148  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
149  *
150  * This is a helper function which notifies all subscribers about a volume
151  * change event (creation, removal, re-sizing, re-naming, updating). Returns
152  * zero in case of success and a negative error code in case of failure.
153  */
154 int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
155 {
156 	int ret;
157 	struct ubi_notification nt;
158 
159 	ubi_do_get_device_info(ubi, &nt.di);
160 	ubi_do_get_volume_info(ubi, vol, &nt.vi);
161 
162 	switch (ntype) {
163 	case UBI_VOLUME_ADDED:
164 	case UBI_VOLUME_REMOVED:
165 	case UBI_VOLUME_RESIZED:
166 	case UBI_VOLUME_RENAMED:
167 		ret = ubi_update_fastmap(ubi);
168 		if (ret)
169 			ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
170 	}
171 
172 	return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
173 }
174 
175 /**
176  * ubi_notify_all - send a notification to all volumes.
177  * @ubi: UBI device description object
178  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
179  * @nb: the notifier to call
180  *
181  * This function walks all volumes of UBI device @ubi and sends the @ntype
182  * notification for each volume. If @nb is %NULL, then all registered notifiers
183  * are called, otherwise only the @nb notifier is called. Returns the number of
184  * sent notifications.
185  */
186 int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
187 {
188 	struct ubi_notification nt;
189 	int i, count = 0;
190 
191 	ubi_do_get_device_info(ubi, &nt.di);
192 
193 	mutex_lock(&ubi->device_mutex);
194 	for (i = 0; i < ubi->vtbl_slots; i++) {
195 		/*
196 		 * Since the @ubi->device is locked, and we are not going to
197 		 * change @ubi->volumes, we do not have to lock
198 		 * @ubi->volumes_lock.
199 		 */
200 		if (!ubi->volumes[i])
201 			continue;
202 
203 		ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
204 		if (nb)
205 			nb->notifier_call(nb, ntype, &nt);
206 		else
207 			blocking_notifier_call_chain(&ubi_notifiers, ntype,
208 						     &nt);
209 		count += 1;
210 	}
211 	mutex_unlock(&ubi->device_mutex);
212 
213 	return count;
214 }
215 
216 /**
217  * ubi_enumerate_volumes - send "add" notification for all existing volumes.
218  * @nb: the notifier to call
219  *
220  * This function walks all UBI devices and volumes and sends the
221  * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
222  * registered notifiers are called, otherwise only the @nb notifier is called.
223  * Returns the number of sent notifications.
224  */
225 int ubi_enumerate_volumes(struct notifier_block *nb)
226 {
227 	int i, count = 0;
228 
229 	/*
230 	 * Since the @ubi_devices_mutex is locked, and we are not going to
231 	 * change @ubi_devices, we do not have to lock @ubi_devices_lock.
232 	 */
233 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
234 		struct ubi_device *ubi = ubi_devices[i];
235 
236 		if (!ubi)
237 			continue;
238 		count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
239 	}
240 
241 	return count;
242 }
243 
244 /**
245  * ubi_get_device - get UBI device.
246  * @ubi_num: UBI device number
247  *
248  * This function returns UBI device description object for UBI device number
249  * @ubi_num, or %NULL if the device does not exist. This function increases the
250  * device reference count to prevent removal of the device. In other words, the
251  * device cannot be removed if its reference count is not zero.
252  */
253 struct ubi_device *ubi_get_device(int ubi_num)
254 {
255 	struct ubi_device *ubi;
256 
257 	spin_lock(&ubi_devices_lock);
258 	ubi = ubi_devices[ubi_num];
259 	if (ubi) {
260 		ubi_assert(ubi->ref_count >= 0);
261 		ubi->ref_count += 1;
262 		get_device(&ubi->dev);
263 	}
264 	spin_unlock(&ubi_devices_lock);
265 
266 	return ubi;
267 }
268 
269 /**
270  * ubi_put_device - drop an UBI device reference.
271  * @ubi: UBI device description object
272  */
273 void ubi_put_device(struct ubi_device *ubi)
274 {
275 	spin_lock(&ubi_devices_lock);
276 	ubi->ref_count -= 1;
277 	put_device(&ubi->dev);
278 	spin_unlock(&ubi_devices_lock);
279 }
280 
281 /**
282  * ubi_get_by_major - get UBI device by character device major number.
283  * @major: major number
284  *
285  * This function is similar to 'ubi_get_device()', but it searches the device
286  * by its major number.
287  */
288 struct ubi_device *ubi_get_by_major(int major)
289 {
290 	int i;
291 	struct ubi_device *ubi;
292 
293 	spin_lock(&ubi_devices_lock);
294 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
295 		ubi = ubi_devices[i];
296 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
297 			ubi_assert(ubi->ref_count >= 0);
298 			ubi->ref_count += 1;
299 			get_device(&ubi->dev);
300 			spin_unlock(&ubi_devices_lock);
301 			return ubi;
302 		}
303 	}
304 	spin_unlock(&ubi_devices_lock);
305 
306 	return NULL;
307 }
308 
309 /**
310  * ubi_major2num - get UBI device number by character device major number.
311  * @major: major number
312  *
313  * This function searches UBI device number object by its major number. If UBI
314  * device was not found, this function returns -ENODEV, otherwise the UBI device
315  * number is returned.
316  */
317 int ubi_major2num(int major)
318 {
319 	int i, ubi_num = -ENODEV;
320 
321 	spin_lock(&ubi_devices_lock);
322 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
323 		struct ubi_device *ubi = ubi_devices[i];
324 
325 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
326 			ubi_num = ubi->ubi_num;
327 			break;
328 		}
329 	}
330 	spin_unlock(&ubi_devices_lock);
331 
332 	return ubi_num;
333 }
334 
335 /* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
336 static ssize_t dev_attribute_show(struct device *dev,
337 				  struct device_attribute *attr, char *buf)
338 {
339 	ssize_t ret;
340 	struct ubi_device *ubi;
341 
342 	/*
343 	 * The below code looks weird, but it actually makes sense. We get the
344 	 * UBI device reference from the contained 'struct ubi_device'. But it
345 	 * is unclear if the device was removed or not yet. Indeed, if the
346 	 * device was removed before we increased its reference count,
347 	 * 'ubi_get_device()' will return -ENODEV and we fail.
348 	 *
349 	 * Remember, 'struct ubi_device' is freed in the release function, so
350 	 * we still can use 'ubi->ubi_num'.
351 	 */
352 	ubi = container_of(dev, struct ubi_device, dev);
353 	ubi = ubi_get_device(ubi->ubi_num);
354 	if (!ubi)
355 		return -ENODEV;
356 
357 	if (attr == &dev_eraseblock_size)
358 		ret = sprintf(buf, "%d\n", ubi->leb_size);
359 	else if (attr == &dev_avail_eraseblocks)
360 		ret = sprintf(buf, "%d\n", ubi->avail_pebs);
361 	else if (attr == &dev_total_eraseblocks)
362 		ret = sprintf(buf, "%d\n", ubi->good_peb_count);
363 	else if (attr == &dev_volumes_count)
364 		ret = sprintf(buf, "%d\n", ubi->vol_count - UBI_INT_VOL_COUNT);
365 	else if (attr == &dev_max_ec)
366 		ret = sprintf(buf, "%d\n", ubi->max_ec);
367 	else if (attr == &dev_reserved_for_bad)
368 		ret = sprintf(buf, "%d\n", ubi->beb_rsvd_pebs);
369 	else if (attr == &dev_bad_peb_count)
370 		ret = sprintf(buf, "%d\n", ubi->bad_peb_count);
371 	else if (attr == &dev_max_vol_count)
372 		ret = sprintf(buf, "%d\n", ubi->vtbl_slots);
373 	else if (attr == &dev_min_io_size)
374 		ret = sprintf(buf, "%d\n", ubi->min_io_size);
375 	else if (attr == &dev_bgt_enabled)
376 		ret = sprintf(buf, "%d\n", ubi->thread_enabled);
377 	else if (attr == &dev_mtd_num)
378 		ret = sprintf(buf, "%d\n", ubi->mtd->index);
379 	else if (attr == &dev_ro_mode)
380 		ret = sprintf(buf, "%d\n", ubi->ro_mode);
381 	else
382 		ret = -EINVAL;
383 
384 	ubi_put_device(ubi);
385 	return ret;
386 }
387 
388 static struct attribute *ubi_dev_attrs[] = {
389 	&dev_eraseblock_size.attr,
390 	&dev_avail_eraseblocks.attr,
391 	&dev_total_eraseblocks.attr,
392 	&dev_volumes_count.attr,
393 	&dev_max_ec.attr,
394 	&dev_reserved_for_bad.attr,
395 	&dev_bad_peb_count.attr,
396 	&dev_max_vol_count.attr,
397 	&dev_min_io_size.attr,
398 	&dev_bgt_enabled.attr,
399 	&dev_mtd_num.attr,
400 	&dev_ro_mode.attr,
401 	NULL
402 };
403 ATTRIBUTE_GROUPS(ubi_dev);
404 
405 static void dev_release(struct device *dev)
406 {
407 	struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);
408 
409 	kfree(ubi);
410 }
411 
412 /**
413  * kill_volumes - destroy all user volumes.
414  * @ubi: UBI device description object
415  */
416 static void kill_volumes(struct ubi_device *ubi)
417 {
418 	int i;
419 
420 	for (i = 0; i < ubi->vtbl_slots; i++)
421 		if (ubi->volumes[i])
422 			ubi_free_volume(ubi, ubi->volumes[i]);
423 }
424 
425 /**
426  * uif_init - initialize user interfaces for an UBI device.
427  * @ubi: UBI device description object
428  *
429  * This function initializes various user interfaces for an UBI device. If the
430  * initialization fails at an early stage, this function frees all the
431  * resources it allocated, returns an error.
432  *
433  * This function returns zero in case of success and a negative error code in
434  * case of failure.
435  */
436 static int uif_init(struct ubi_device *ubi)
437 {
438 	int i, err;
439 	dev_t dev;
440 
441 	sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);
442 
443 	/*
444 	 * Major numbers for the UBI character devices are allocated
445 	 * dynamically. Major numbers of volume character devices are
446 	 * equivalent to ones of the corresponding UBI character device. Minor
447 	 * numbers of UBI character devices are 0, while minor numbers of
448 	 * volume character devices start from 1. Thus, we allocate one major
449 	 * number and ubi->vtbl_slots + 1 minor numbers.
450 	 */
451 	err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
452 	if (err) {
453 		ubi_err(ubi, "cannot register UBI character devices");
454 		return err;
455 	}
456 
457 	ubi->dev.devt = dev;
458 
459 	ubi_assert(MINOR(dev) == 0);
460 	cdev_init(&ubi->cdev, &ubi_cdev_operations);
461 	dbg_gen("%s major is %u", ubi->ubi_name, MAJOR(dev));
462 	ubi->cdev.owner = THIS_MODULE;
463 
464 	dev_set_name(&ubi->dev, UBI_NAME_STR "%d", ubi->ubi_num);
465 	err = cdev_device_add(&ubi->cdev, &ubi->dev);
466 	if (err)
467 		goto out_unreg;
468 
469 	for (i = 0; i < ubi->vtbl_slots; i++)
470 		if (ubi->volumes[i]) {
471 			err = ubi_add_volume(ubi, ubi->volumes[i]);
472 			if (err) {
473 				ubi_err(ubi, "cannot add volume %d", i);
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_assert(ubi->mtd->writesize == 1);
633 		ubi->nor_flash = 1;
634 	}
635 
636 	ubi->min_io_size = ubi->mtd->writesize;
637 	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
638 
639 	/*
640 	 * Make sure minimal I/O unit is power of 2. Note, there is no
641 	 * fundamental reason for this assumption. It is just an optimization
642 	 * which allows us to avoid costly division operations.
643 	 */
644 	if (!is_power_of_2(ubi->min_io_size)) {
645 		ubi_err(ubi, "min. I/O unit (%d) is not power of 2",
646 			ubi->min_io_size);
647 		return -EINVAL;
648 	}
649 
650 	ubi_assert(ubi->hdrs_min_io_size > 0);
651 	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
652 	ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
653 
654 	ubi->max_write_size = ubi->mtd->writebufsize;
655 	/*
656 	 * Maximum write size has to be greater or equivalent to min. I/O
657 	 * size, and be multiple of min. I/O size.
658 	 */
659 	if (ubi->max_write_size < ubi->min_io_size ||
660 	    ubi->max_write_size % ubi->min_io_size ||
661 	    !is_power_of_2(ubi->max_write_size)) {
662 		ubi_err(ubi, "bad write buffer size %d for %d min. I/O unit",
663 			ubi->max_write_size, ubi->min_io_size);
664 		return -EINVAL;
665 	}
666 
667 	/* Calculate default aligned sizes of EC and VID headers */
668 	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
669 	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
670 
671 	dbg_gen("min_io_size      %d", ubi->min_io_size);
672 	dbg_gen("max_write_size   %d", ubi->max_write_size);
673 	dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
674 	dbg_gen("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
675 	dbg_gen("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
676 
677 	if (ubi->vid_hdr_offset == 0)
678 		/* Default offset */
679 		ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
680 				      ubi->ec_hdr_alsize;
681 	else {
682 		ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
683 						~(ubi->hdrs_min_io_size - 1);
684 		ubi->vid_hdr_shift = ubi->vid_hdr_offset -
685 						ubi->vid_hdr_aloffset;
686 	}
687 
688 	/* Similar for the data offset */
689 	ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
690 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
691 
692 	dbg_gen("vid_hdr_offset   %d", ubi->vid_hdr_offset);
693 	dbg_gen("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
694 	dbg_gen("vid_hdr_shift    %d", ubi->vid_hdr_shift);
695 	dbg_gen("leb_start        %d", ubi->leb_start);
696 
697 	/* The shift must be aligned to 32-bit boundary */
698 	if (ubi->vid_hdr_shift % 4) {
699 		ubi_err(ubi, "unaligned VID header shift %d",
700 			ubi->vid_hdr_shift);
701 		return -EINVAL;
702 	}
703 
704 	/* Check sanity */
705 	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
706 	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
707 	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
708 	    ubi->leb_start & (ubi->min_io_size - 1)) {
709 		ubi_err(ubi, "bad VID header (%d) or data offsets (%d)",
710 			ubi->vid_hdr_offset, ubi->leb_start);
711 		return -EINVAL;
712 	}
713 
714 	/*
715 	 * Set maximum amount of physical erroneous eraseblocks to be 10%.
716 	 * Erroneous PEB are those which have read errors.
717 	 */
718 	ubi->max_erroneous = ubi->peb_count / 10;
719 	if (ubi->max_erroneous < 16)
720 		ubi->max_erroneous = 16;
721 	dbg_gen("max_erroneous    %d", ubi->max_erroneous);
722 
723 	/*
724 	 * It may happen that EC and VID headers are situated in one minimal
725 	 * I/O unit. In this case we can only accept this UBI image in
726 	 * read-only mode.
727 	 */
728 	if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
729 		ubi_warn(ubi, "EC and VID headers are in the same minimal I/O unit, switch to read-only mode");
730 		ubi->ro_mode = 1;
731 	}
732 
733 	ubi->leb_size = ubi->peb_size - ubi->leb_start;
734 
735 	if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
736 		ubi_msg(ubi, "MTD device %d is write-protected, attach in read-only mode",
737 			ubi->mtd->index);
738 		ubi->ro_mode = 1;
739 	}
740 
741 	/*
742 	 * Note, ideally, we have to initialize @ubi->bad_peb_count here. But
743 	 * unfortunately, MTD does not provide this information. We should loop
744 	 * over all physical eraseblocks and invoke mtd->block_is_bad() for
745 	 * each physical eraseblock. So, we leave @ubi->bad_peb_count
746 	 * uninitialized so far.
747 	 */
748 
749 	return 0;
750 }
751 
752 /**
753  * autoresize - re-size the volume which has the "auto-resize" flag set.
754  * @ubi: UBI device description object
755  * @vol_id: ID of the volume to re-size
756  *
757  * This function re-sizes the volume marked by the %UBI_VTBL_AUTORESIZE_FLG in
758  * the volume table to the largest possible size. See comments in ubi-header.h
759  * for more description of the flag. Returns zero in case of success and a
760  * negative error code in case of failure.
761  */
762 static int autoresize(struct ubi_device *ubi, int vol_id)
763 {
764 	struct ubi_volume_desc desc;
765 	struct ubi_volume *vol = ubi->volumes[vol_id];
766 	int err, old_reserved_pebs = vol->reserved_pebs;
767 
768 	if (ubi->ro_mode) {
769 		ubi_warn(ubi, "skip auto-resize because of R/O mode");
770 		return 0;
771 	}
772 
773 	/*
774 	 * Clear the auto-resize flag in the volume in-memory copy of the
775 	 * volume table, and 'ubi_resize_volume()' will propagate this change
776 	 * to the flash.
777 	 */
778 	ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;
779 
780 	if (ubi->avail_pebs == 0) {
781 		struct ubi_vtbl_record vtbl_rec;
782 
783 		/*
784 		 * No available PEBs to re-size the volume, clear the flag on
785 		 * flash and exit.
786 		 */
787 		vtbl_rec = ubi->vtbl[vol_id];
788 		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
789 		if (err)
790 			ubi_err(ubi, "cannot clean auto-resize flag for volume %d",
791 				vol_id);
792 	} else {
793 		desc.vol = vol;
794 		err = ubi_resize_volume(&desc,
795 					old_reserved_pebs + ubi->avail_pebs);
796 		if (err)
797 			ubi_err(ubi, "cannot auto-resize volume %d",
798 				vol_id);
799 	}
800 
801 	if (err)
802 		return err;
803 
804 	ubi_msg(ubi, "volume %d (\"%s\") re-sized from %d to %d LEBs",
805 		vol_id, vol->name, old_reserved_pebs, vol->reserved_pebs);
806 	return 0;
807 }
808 
809 /**
810  * ubi_attach_mtd_dev - attach an MTD device.
811  * @mtd: MTD device description object
812  * @ubi_num: number to assign to the new UBI device
813  * @vid_hdr_offset: VID header offset
814  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
815  *
816  * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
817  * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
818  * which case this function finds a vacant device number and assigns it
819  * automatically. Returns the new UBI device number in case of success and a
820  * negative error code in case of failure.
821  *
822  * Note, the invocations of this function has to be serialized by the
823  * @ubi_devices_mutex.
824  */
825 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
826 		       int vid_hdr_offset, int max_beb_per1024)
827 {
828 	struct ubi_device *ubi;
829 	int i, err;
830 
831 	if (max_beb_per1024 < 0 || max_beb_per1024 > MAX_MTD_UBI_BEB_LIMIT)
832 		return -EINVAL;
833 
834 	if (!max_beb_per1024)
835 		max_beb_per1024 = CONFIG_MTD_UBI_BEB_LIMIT;
836 
837 	/*
838 	 * Check if we already have the same MTD device attached.
839 	 *
840 	 * Note, this function assumes that UBI devices creations and deletions
841 	 * are serialized, so it does not take the &ubi_devices_lock.
842 	 */
843 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
844 		ubi = ubi_devices[i];
845 		if (ubi && mtd->index == ubi->mtd->index) {
846 			pr_err("ubi: mtd%d is already attached to ubi%d\n",
847 				mtd->index, i);
848 			return -EEXIST;
849 		}
850 	}
851 
852 	/*
853 	 * Make sure this MTD device is not emulated on top of an UBI volume
854 	 * already. Well, generally this recursion works fine, but there are
855 	 * different problems like the UBI module takes a reference to itself
856 	 * by attaching (and thus, opening) the emulated MTD device. This
857 	 * results in inability to unload the module. And in general it makes
858 	 * no sense to attach emulated MTD devices, so we prohibit this.
859 	 */
860 	if (mtd->type == MTD_UBIVOLUME) {
861 		pr_err("ubi: refuse attaching mtd%d - it is already emulated on top of UBI\n",
862 			mtd->index);
863 		return -EINVAL;
864 	}
865 
866 	/*
867 	 * Both UBI and UBIFS have been designed for SLC NAND and NOR flashes.
868 	 * MLC NAND is different and needs special care, otherwise UBI or UBIFS
869 	 * will die soon and you will lose all your data.
870 	 * Relax this rule if the partition we're attaching to operates in SLC
871 	 * mode.
872 	 */
873 	if (mtd->type == MTD_MLCNANDFLASH &&
874 	    !(mtd->flags & MTD_SLC_ON_MLC_EMULATION)) {
875 		pr_err("ubi: refuse attaching mtd%d - MLC NAND is not supported\n",
876 			mtd->index);
877 		return -EINVAL;
878 	}
879 
880 	if (ubi_num == UBI_DEV_NUM_AUTO) {
881 		/* Search for an empty slot in the @ubi_devices array */
882 		for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
883 			if (!ubi_devices[ubi_num])
884 				break;
885 		if (ubi_num == UBI_MAX_DEVICES) {
886 			pr_err("ubi: only %d UBI devices may be created\n",
887 				UBI_MAX_DEVICES);
888 			return -ENFILE;
889 		}
890 	} else {
891 		if (ubi_num >= UBI_MAX_DEVICES)
892 			return -EINVAL;
893 
894 		/* Make sure ubi_num is not busy */
895 		if (ubi_devices[ubi_num]) {
896 			pr_err("ubi: ubi%i already exists\n", ubi_num);
897 			return -EEXIST;
898 		}
899 	}
900 
901 	ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
902 	if (!ubi)
903 		return -ENOMEM;
904 
905 	device_initialize(&ubi->dev);
906 	ubi->dev.release = dev_release;
907 	ubi->dev.class = &ubi_class;
908 	ubi->dev.groups = ubi_dev_groups;
909 
910 	ubi->mtd = mtd;
911 	ubi->ubi_num = ubi_num;
912 	ubi->vid_hdr_offset = vid_hdr_offset;
913 	ubi->autoresize_vol_id = -1;
914 
915 #ifdef CONFIG_MTD_UBI_FASTMAP
916 	ubi->fm_pool.used = ubi->fm_pool.size = 0;
917 	ubi->fm_wl_pool.used = ubi->fm_wl_pool.size = 0;
918 
919 	/*
920 	 * fm_pool.max_size is 5% of the total number of PEBs but it's also
921 	 * between UBI_FM_MAX_POOL_SIZE and UBI_FM_MIN_POOL_SIZE.
922 	 */
923 	ubi->fm_pool.max_size = min(((int)mtd_div_by_eb(ubi->mtd->size,
924 		ubi->mtd) / 100) * 5, UBI_FM_MAX_POOL_SIZE);
925 	ubi->fm_pool.max_size = max(ubi->fm_pool.max_size,
926 		UBI_FM_MIN_POOL_SIZE);
927 
928 	ubi->fm_wl_pool.max_size = ubi->fm_pool.max_size / 2;
929 	ubi->fm_disabled = !fm_autoconvert;
930 	if (fm_debug)
931 		ubi_enable_dbg_chk_fastmap(ubi);
932 
933 	if (!ubi->fm_disabled && (int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd)
934 	    <= UBI_FM_MAX_START) {
935 		ubi_err(ubi, "More than %i PEBs are needed for fastmap, sorry.",
936 			UBI_FM_MAX_START);
937 		ubi->fm_disabled = 1;
938 	}
939 
940 	ubi_msg(ubi, "default fastmap pool size: %d", ubi->fm_pool.max_size);
941 	ubi_msg(ubi, "default fastmap WL pool size: %d",
942 		ubi->fm_wl_pool.max_size);
943 #else
944 	ubi->fm_disabled = 1;
945 #endif
946 	mutex_init(&ubi->buf_mutex);
947 	mutex_init(&ubi->ckvol_mutex);
948 	mutex_init(&ubi->device_mutex);
949 	spin_lock_init(&ubi->volumes_lock);
950 	init_rwsem(&ubi->fm_protect);
951 	init_rwsem(&ubi->fm_eba_sem);
952 
953 	ubi_msg(ubi, "attaching mtd%d", mtd->index);
954 
955 	err = io_init(ubi, max_beb_per1024);
956 	if (err)
957 		goto out_free;
958 
959 	err = -ENOMEM;
960 	ubi->peb_buf = vmalloc(ubi->peb_size);
961 	if (!ubi->peb_buf)
962 		goto out_free;
963 
964 #ifdef CONFIG_MTD_UBI_FASTMAP
965 	ubi->fm_size = ubi_calc_fm_size(ubi);
966 	ubi->fm_buf = vzalloc(ubi->fm_size);
967 	if (!ubi->fm_buf)
968 		goto out_free;
969 #endif
970 	err = ubi_attach(ubi, 0);
971 	if (err) {
972 		ubi_err(ubi, "failed to attach mtd%d, error %d",
973 			mtd->index, err);
974 		goto out_free;
975 	}
976 
977 	if (ubi->autoresize_vol_id != -1) {
978 		err = autoresize(ubi, ubi->autoresize_vol_id);
979 		if (err)
980 			goto out_detach;
981 	}
982 
983 	/* Make device "available" before it becomes accessible via sysfs */
984 	ubi_devices[ubi_num] = ubi;
985 
986 	err = uif_init(ubi);
987 	if (err)
988 		goto out_detach;
989 
990 	err = ubi_debugfs_init_dev(ubi);
991 	if (err)
992 		goto out_uif;
993 
994 	ubi->bgt_thread = kthread_create(ubi_thread, ubi, "%s", ubi->bgt_name);
995 	if (IS_ERR(ubi->bgt_thread)) {
996 		err = PTR_ERR(ubi->bgt_thread);
997 		ubi_err(ubi, "cannot spawn \"%s\", error %d",
998 			ubi->bgt_name, err);
999 		goto out_debugfs;
1000 	}
1001 
1002 	ubi_msg(ubi, "attached mtd%d (name \"%s\", size %llu MiB)",
1003 		mtd->index, mtd->name, ubi->flash_size >> 20);
1004 	ubi_msg(ubi, "PEB size: %d bytes (%d KiB), LEB size: %d bytes",
1005 		ubi->peb_size, ubi->peb_size >> 10, ubi->leb_size);
1006 	ubi_msg(ubi, "min./max. I/O unit sizes: %d/%d, sub-page size %d",
1007 		ubi->min_io_size, ubi->max_write_size, ubi->hdrs_min_io_size);
1008 	ubi_msg(ubi, "VID header offset: %d (aligned %d), data offset: %d",
1009 		ubi->vid_hdr_offset, ubi->vid_hdr_aloffset, ubi->leb_start);
1010 	ubi_msg(ubi, "good PEBs: %d, bad PEBs: %d, corrupted PEBs: %d",
1011 		ubi->good_peb_count, ubi->bad_peb_count, ubi->corr_peb_count);
1012 	ubi_msg(ubi, "user volume: %d, internal volumes: %d, max. volumes count: %d",
1013 		ubi->vol_count - UBI_INT_VOL_COUNT, UBI_INT_VOL_COUNT,
1014 		ubi->vtbl_slots);
1015 	ubi_msg(ubi, "max/mean erase counter: %d/%d, WL threshold: %d, image sequence number: %u",
1016 		ubi->max_ec, ubi->mean_ec, CONFIG_MTD_UBI_WL_THRESHOLD,
1017 		ubi->image_seq);
1018 	ubi_msg(ubi, "available PEBs: %d, total reserved PEBs: %d, PEBs reserved for bad PEB handling: %d",
1019 		ubi->avail_pebs, ubi->rsvd_pebs, ubi->beb_rsvd_pebs);
1020 
1021 	/*
1022 	 * The below lock makes sure we do not race with 'ubi_thread()' which
1023 	 * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
1024 	 */
1025 	spin_lock(&ubi->wl_lock);
1026 	ubi->thread_enabled = 1;
1027 	wake_up_process(ubi->bgt_thread);
1028 	spin_unlock(&ubi->wl_lock);
1029 
1030 	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
1031 	return ubi_num;
1032 
1033 out_debugfs:
1034 	ubi_debugfs_exit_dev(ubi);
1035 out_uif:
1036 	uif_close(ubi);
1037 out_detach:
1038 	ubi_devices[ubi_num] = NULL;
1039 	ubi_wl_close(ubi);
1040 	ubi_free_all_volumes(ubi);
1041 	vfree(ubi->vtbl);
1042 out_free:
1043 	vfree(ubi->peb_buf);
1044 	vfree(ubi->fm_buf);
1045 	put_device(&ubi->dev);
1046 	return err;
1047 }
1048 
1049 /**
1050  * ubi_detach_mtd_dev - detach an MTD device.
1051  * @ubi_num: UBI device number to detach from
1052  * @anyway: detach MTD even if device reference count is not zero
1053  *
1054  * This function destroys an UBI device number @ubi_num and detaches the
1055  * underlying MTD device. Returns zero in case of success and %-EBUSY if the
1056  * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
1057  * exist.
1058  *
1059  * Note, the invocations of this function has to be serialized by the
1060  * @ubi_devices_mutex.
1061  */
1062 int ubi_detach_mtd_dev(int ubi_num, int anyway)
1063 {
1064 	struct ubi_device *ubi;
1065 
1066 	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
1067 		return -EINVAL;
1068 
1069 	ubi = ubi_get_device(ubi_num);
1070 	if (!ubi)
1071 		return -EINVAL;
1072 
1073 	spin_lock(&ubi_devices_lock);
1074 	put_device(&ubi->dev);
1075 	ubi->ref_count -= 1;
1076 	if (ubi->ref_count) {
1077 		if (!anyway) {
1078 			spin_unlock(&ubi_devices_lock);
1079 			return -EBUSY;
1080 		}
1081 		/* This may only happen if there is a bug */
1082 		ubi_err(ubi, "%s reference count %d, destroy anyway",
1083 			ubi->ubi_name, ubi->ref_count);
1084 	}
1085 	ubi_devices[ubi_num] = NULL;
1086 	spin_unlock(&ubi_devices_lock);
1087 
1088 	ubi_assert(ubi_num == ubi->ubi_num);
1089 	ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
1090 	ubi_msg(ubi, "detaching mtd%d", ubi->mtd->index);
1091 #ifdef CONFIG_MTD_UBI_FASTMAP
1092 	/* If we don't write a new fastmap at detach time we lose all
1093 	 * EC updates that have been made since the last written fastmap.
1094 	 * In case of fastmap debugging we omit the update to simulate an
1095 	 * unclean shutdown. */
1096 	if (!ubi_dbg_chk_fastmap(ubi))
1097 		ubi_update_fastmap(ubi);
1098 #endif
1099 	/*
1100 	 * Before freeing anything, we have to stop the background thread to
1101 	 * prevent it from doing anything on this device while we are freeing.
1102 	 */
1103 	if (ubi->bgt_thread)
1104 		kthread_stop(ubi->bgt_thread);
1105 
1106 #ifdef CONFIG_MTD_UBI_FASTMAP
1107 	cancel_work_sync(&ubi->fm_work);
1108 #endif
1109 	ubi_debugfs_exit_dev(ubi);
1110 	uif_close(ubi);
1111 
1112 	ubi_wl_close(ubi);
1113 	ubi_free_internal_volumes(ubi);
1114 	vfree(ubi->vtbl);
1115 	vfree(ubi->peb_buf);
1116 	vfree(ubi->fm_buf);
1117 	ubi_msg(ubi, "mtd%d is detached", ubi->mtd->index);
1118 	put_mtd_device(ubi->mtd);
1119 	put_device(&ubi->dev);
1120 	return 0;
1121 }
1122 
1123 /**
1124  * open_mtd_by_chdev - open an MTD device by its character device node path.
1125  * @mtd_dev: MTD character device node path
1126  *
1127  * This helper function opens an MTD device by its character node device path.
1128  * Returns MTD device description object in case of success and a negative
1129  * error code in case of failure.
1130  */
1131 static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
1132 {
1133 	int err, minor;
1134 	struct path path;
1135 	struct kstat stat;
1136 
1137 	/* Probably this is an MTD character device node path */
1138 	err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
1139 	if (err)
1140 		return ERR_PTR(err);
1141 
1142 	err = vfs_getattr(&path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
1143 	path_put(&path);
1144 	if (err)
1145 		return ERR_PTR(err);
1146 
1147 	/* MTD device number is defined by the major / minor numbers */
1148 	if (MAJOR(stat.rdev) != MTD_CHAR_MAJOR || !S_ISCHR(stat.mode))
1149 		return ERR_PTR(-EINVAL);
1150 
1151 	minor = MINOR(stat.rdev);
1152 
1153 	if (minor & 1)
1154 		/*
1155 		 * Just do not think the "/dev/mtdrX" devices support is need,
1156 		 * so do not support them to avoid doing extra work.
1157 		 */
1158 		return ERR_PTR(-EINVAL);
1159 
1160 	return get_mtd_device(NULL, minor / 2);
1161 }
1162 
1163 /**
1164  * open_mtd_device - open MTD device by name, character device path, or number.
1165  * @mtd_dev: name, character device node path, or MTD device device number
1166  *
1167  * This function tries to open and MTD device described by @mtd_dev string,
1168  * which is first treated as ASCII MTD device number, and if it is not true, it
1169  * is treated as MTD device name, and if that is also not true, it is treated
1170  * as MTD character device node path. Returns MTD device description object in
1171  * case of success and a negative error code in case of failure.
1172  */
1173 static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
1174 {
1175 	struct mtd_info *mtd;
1176 	int mtd_num;
1177 	char *endp;
1178 
1179 	mtd_num = simple_strtoul(mtd_dev, &endp, 0);
1180 	if (*endp != '\0' || mtd_dev == endp) {
1181 		/*
1182 		 * This does not look like an ASCII integer, probably this is
1183 		 * MTD device name.
1184 		 */
1185 		mtd = get_mtd_device_nm(mtd_dev);
1186 		if (PTR_ERR(mtd) == -ENODEV)
1187 			/* Probably this is an MTD character device node path */
1188 			mtd = open_mtd_by_chdev(mtd_dev);
1189 	} else
1190 		mtd = get_mtd_device(NULL, mtd_num);
1191 
1192 	return mtd;
1193 }
1194 
1195 static int __init ubi_init(void)
1196 {
1197 	int err, i, k;
1198 
1199 	/* Ensure that EC and VID headers have correct size */
1200 	BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
1201 	BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);
1202 
1203 	if (mtd_devs > UBI_MAX_DEVICES) {
1204 		pr_err("UBI error: too many MTD devices, maximum is %d\n",
1205 		       UBI_MAX_DEVICES);
1206 		return -EINVAL;
1207 	}
1208 
1209 	/* Create base sysfs directory and sysfs files */
1210 	err = class_register(&ubi_class);
1211 	if (err < 0)
1212 		return err;
1213 
1214 	err = misc_register(&ubi_ctrl_cdev);
1215 	if (err) {
1216 		pr_err("UBI error: cannot register device\n");
1217 		goto out;
1218 	}
1219 
1220 	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
1221 					      sizeof(struct ubi_wl_entry),
1222 					      0, 0, NULL);
1223 	if (!ubi_wl_entry_slab) {
1224 		err = -ENOMEM;
1225 		goto out_dev_unreg;
1226 	}
1227 
1228 	err = ubi_debugfs_init();
1229 	if (err)
1230 		goto out_slab;
1231 
1232 
1233 	/* Attach MTD devices */
1234 	for (i = 0; i < mtd_devs; i++) {
1235 		struct mtd_dev_param *p = &mtd_dev_param[i];
1236 		struct mtd_info *mtd;
1237 
1238 		cond_resched();
1239 
1240 		mtd = open_mtd_device(p->name);
1241 		if (IS_ERR(mtd)) {
1242 			err = PTR_ERR(mtd);
1243 			pr_err("UBI error: cannot open mtd %s, error %d\n",
1244 			       p->name, err);
1245 			/* See comment below re-ubi_is_module(). */
1246 			if (ubi_is_module())
1247 				goto out_detach;
1248 			continue;
1249 		}
1250 
1251 		mutex_lock(&ubi_devices_mutex);
1252 		err = ubi_attach_mtd_dev(mtd, p->ubi_num,
1253 					 p->vid_hdr_offs, p->max_beb_per1024);
1254 		mutex_unlock(&ubi_devices_mutex);
1255 		if (err < 0) {
1256 			pr_err("UBI error: cannot attach mtd%d\n",
1257 			       mtd->index);
1258 			put_mtd_device(mtd);
1259 
1260 			/*
1261 			 * Originally UBI stopped initializing on any error.
1262 			 * However, later on it was found out that this
1263 			 * behavior is not very good when UBI is compiled into
1264 			 * the kernel and the MTD devices to attach are passed
1265 			 * through the command line. Indeed, UBI failure
1266 			 * stopped whole boot sequence.
1267 			 *
1268 			 * To fix this, we changed the behavior for the
1269 			 * non-module case, but preserved the old behavior for
1270 			 * the module case, just for compatibility. This is a
1271 			 * little inconsistent, though.
1272 			 */
1273 			if (ubi_is_module())
1274 				goto out_detach;
1275 		}
1276 	}
1277 
1278 	err = ubiblock_init();
1279 	if (err) {
1280 		pr_err("UBI error: block: cannot initialize, error %d\n", err);
1281 
1282 		/* See comment above re-ubi_is_module(). */
1283 		if (ubi_is_module())
1284 			goto out_detach;
1285 	}
1286 
1287 	return 0;
1288 
1289 out_detach:
1290 	for (k = 0; k < i; k++)
1291 		if (ubi_devices[k]) {
1292 			mutex_lock(&ubi_devices_mutex);
1293 			ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
1294 			mutex_unlock(&ubi_devices_mutex);
1295 		}
1296 	ubi_debugfs_exit();
1297 out_slab:
1298 	kmem_cache_destroy(ubi_wl_entry_slab);
1299 out_dev_unreg:
1300 	misc_deregister(&ubi_ctrl_cdev);
1301 out:
1302 	class_unregister(&ubi_class);
1303 	pr_err("UBI error: cannot initialize UBI, error %d\n", err);
1304 	return err;
1305 }
1306 late_initcall(ubi_init);
1307 
1308 static void __exit ubi_exit(void)
1309 {
1310 	int i;
1311 
1312 	ubiblock_exit();
1313 
1314 	for (i = 0; i < UBI_MAX_DEVICES; i++)
1315 		if (ubi_devices[i]) {
1316 			mutex_lock(&ubi_devices_mutex);
1317 			ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
1318 			mutex_unlock(&ubi_devices_mutex);
1319 		}
1320 	ubi_debugfs_exit();
1321 	kmem_cache_destroy(ubi_wl_entry_slab);
1322 	misc_deregister(&ubi_ctrl_cdev);
1323 	class_unregister(&ubi_class);
1324 }
1325 module_exit(ubi_exit);
1326 
1327 /**
1328  * bytes_str_to_int - convert a number of bytes string into an integer.
1329  * @str: the string to convert
1330  *
1331  * This function returns positive resulting integer in case of success and a
1332  * negative error code in case of failure.
1333  */
1334 static int bytes_str_to_int(const char *str)
1335 {
1336 	char *endp;
1337 	unsigned long result;
1338 
1339 	result = simple_strtoul(str, &endp, 0);
1340 	if (str == endp || result >= INT_MAX) {
1341 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1342 		return -EINVAL;
1343 	}
1344 
1345 	switch (*endp) {
1346 	case 'G':
1347 		result *= 1024;
1348 		fallthrough;
1349 	case 'M':
1350 		result *= 1024;
1351 		fallthrough;
1352 	case 'K':
1353 		result *= 1024;
1354 		if (endp[1] == 'i' && endp[2] == 'B')
1355 			endp += 2;
1356 	case '\0':
1357 		break;
1358 	default:
1359 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1360 		return -EINVAL;
1361 	}
1362 
1363 	return result;
1364 }
1365 
1366 /**
1367  * ubi_mtd_param_parse - parse the 'mtd=' UBI parameter.
1368  * @val: the parameter value to parse
1369  * @kp: not used
1370  *
1371  * This function returns zero in case of success and a negative error code in
1372  * case of error.
1373  */
1374 static int ubi_mtd_param_parse(const char *val, const struct kernel_param *kp)
1375 {
1376 	int i, len;
1377 	struct mtd_dev_param *p;
1378 	char buf[MTD_PARAM_LEN_MAX];
1379 	char *pbuf = &buf[0];
1380 	char *tokens[MTD_PARAM_MAX_COUNT], *token;
1381 
1382 	if (!val)
1383 		return -EINVAL;
1384 
1385 	if (mtd_devs == UBI_MAX_DEVICES) {
1386 		pr_err("UBI error: too many parameters, max. is %d\n",
1387 		       UBI_MAX_DEVICES);
1388 		return -EINVAL;
1389 	}
1390 
1391 	len = strnlen(val, MTD_PARAM_LEN_MAX);
1392 	if (len == MTD_PARAM_LEN_MAX) {
1393 		pr_err("UBI error: parameter \"%s\" is too long, max. is %d\n",
1394 		       val, MTD_PARAM_LEN_MAX);
1395 		return -EINVAL;
1396 	}
1397 
1398 	if (len == 0) {
1399 		pr_warn("UBI warning: empty 'mtd=' parameter - ignored\n");
1400 		return 0;
1401 	}
1402 
1403 	strcpy(buf, val);
1404 
1405 	/* Get rid of the final newline */
1406 	if (buf[len - 1] == '\n')
1407 		buf[len - 1] = '\0';
1408 
1409 	for (i = 0; i < MTD_PARAM_MAX_COUNT; i++)
1410 		tokens[i] = strsep(&pbuf, ",");
1411 
1412 	if (pbuf) {
1413 		pr_err("UBI error: too many arguments at \"%s\"\n", val);
1414 		return -EINVAL;
1415 	}
1416 
1417 	p = &mtd_dev_param[mtd_devs];
1418 	strcpy(&p->name[0], tokens[0]);
1419 
1420 	token = tokens[1];
1421 	if (token) {
1422 		p->vid_hdr_offs = bytes_str_to_int(token);
1423 
1424 		if (p->vid_hdr_offs < 0)
1425 			return p->vid_hdr_offs;
1426 	}
1427 
1428 	token = tokens[2];
1429 	if (token) {
1430 		int err = kstrtoint(token, 10, &p->max_beb_per1024);
1431 
1432 		if (err) {
1433 			pr_err("UBI error: bad value for max_beb_per1024 parameter: %s",
1434 			       token);
1435 			return -EINVAL;
1436 		}
1437 	}
1438 
1439 	token = tokens[3];
1440 	if (token) {
1441 		int err = kstrtoint(token, 10, &p->ubi_num);
1442 
1443 		if (err) {
1444 			pr_err("UBI error: bad value for ubi_num parameter: %s",
1445 			       token);
1446 			return -EINVAL;
1447 		}
1448 	} else
1449 		p->ubi_num = UBI_DEV_NUM_AUTO;
1450 
1451 	mtd_devs += 1;
1452 	return 0;
1453 }
1454 
1455 module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 0400);
1456 MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024[,ubi_num]]].\n"
1457 		      "Multiple \"mtd\" parameters may be specified.\n"
1458 		      "MTD devices may be specified by their number, name, or path to the MTD character device node.\n"
1459 		      "Optional \"vid_hdr_offs\" parameter specifies UBI VID header position to be used by UBI. (default value if 0)\n"
1460 		      "Optional \"max_beb_per1024\" parameter specifies the maximum expected bad eraseblock per 1024 eraseblocks. (default value ("
1461 		      __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0)\n"
1462 		      "Optional \"ubi_num\" parameter specifies UBI device number which have to be assigned to the newly created UBI device (assigned automatically by default)\n"
1463 		      "\n"
1464 		      "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
1465 		      "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"
1466 		      "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"
1467 		      "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"
1468 		      "\t(e.g. if the NAND *chipset* has 4096 PEB, 100 will be reserved for this UBI device).");
1469 #ifdef CONFIG_MTD_UBI_FASTMAP
1470 module_param(fm_autoconvert, bool, 0644);
1471 MODULE_PARM_DESC(fm_autoconvert, "Set this parameter to enable fastmap automatically on images without a fastmap.");
1472 module_param(fm_debug, bool, 0);
1473 MODULE_PARM_DESC(fm_debug, "Set this parameter to enable fastmap debugging by default. Warning, this will make fastmap slow!");
1474 #endif
1475 MODULE_VERSION(__stringify(UBI_VERSION));
1476 MODULE_DESCRIPTION("UBI - Unsorted Block Images");
1477 MODULE_AUTHOR("Artem Bityutskiy");
1478 MODULE_LICENSE("GPL");
1479