xref: /openbmc/linux/drivers/mtd/ubi/build.c (revision 31354121)
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 
355 	if (attr == &dev_eraseblock_size)
356 		ret = sprintf(buf, "%d\n", ubi->leb_size);
357 	else if (attr == &dev_avail_eraseblocks)
358 		ret = sprintf(buf, "%d\n", ubi->avail_pebs);
359 	else if (attr == &dev_total_eraseblocks)
360 		ret = sprintf(buf, "%d\n", ubi->good_peb_count);
361 	else if (attr == &dev_volumes_count)
362 		ret = sprintf(buf, "%d\n", ubi->vol_count - UBI_INT_VOL_COUNT);
363 	else if (attr == &dev_max_ec)
364 		ret = sprintf(buf, "%d\n", ubi->max_ec);
365 	else if (attr == &dev_reserved_for_bad)
366 		ret = sprintf(buf, "%d\n", ubi->beb_rsvd_pebs);
367 	else if (attr == &dev_bad_peb_count)
368 		ret = sprintf(buf, "%d\n", ubi->bad_peb_count);
369 	else if (attr == &dev_max_vol_count)
370 		ret = sprintf(buf, "%d\n", ubi->vtbl_slots);
371 	else if (attr == &dev_min_io_size)
372 		ret = sprintf(buf, "%d\n", ubi->min_io_size);
373 	else if (attr == &dev_bgt_enabled)
374 		ret = sprintf(buf, "%d\n", ubi->thread_enabled);
375 	else if (attr == &dev_mtd_num)
376 		ret = sprintf(buf, "%d\n", ubi->mtd->index);
377 	else if (attr == &dev_ro_mode)
378 		ret = sprintf(buf, "%d\n", ubi->ro_mode);
379 	else
380 		ret = -EINVAL;
381 
382 	return ret;
383 }
384 
385 static struct attribute *ubi_dev_attrs[] = {
386 	&dev_eraseblock_size.attr,
387 	&dev_avail_eraseblocks.attr,
388 	&dev_total_eraseblocks.attr,
389 	&dev_volumes_count.attr,
390 	&dev_max_ec.attr,
391 	&dev_reserved_for_bad.attr,
392 	&dev_bad_peb_count.attr,
393 	&dev_max_vol_count.attr,
394 	&dev_min_io_size.attr,
395 	&dev_bgt_enabled.attr,
396 	&dev_mtd_num.attr,
397 	&dev_ro_mode.attr,
398 	NULL
399 };
400 ATTRIBUTE_GROUPS(ubi_dev);
401 
402 static void dev_release(struct device *dev)
403 {
404 	struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);
405 
406 	kfree(ubi);
407 }
408 
409 /**
410  * kill_volumes - destroy all user volumes.
411  * @ubi: UBI device description object
412  */
413 static void kill_volumes(struct ubi_device *ubi)
414 {
415 	int i;
416 
417 	for (i = 0; i < ubi->vtbl_slots; i++)
418 		if (ubi->volumes[i])
419 			ubi_free_volume(ubi, ubi->volumes[i]);
420 }
421 
422 /**
423  * uif_init - initialize user interfaces for an UBI device.
424  * @ubi: UBI device description object
425  *
426  * This function initializes various user interfaces for an UBI device. If the
427  * initialization fails at an early stage, this function frees all the
428  * resources it allocated, returns an error.
429  *
430  * This function returns zero in case of success and a negative error code in
431  * case of failure.
432  */
433 static int uif_init(struct ubi_device *ubi)
434 {
435 	int i, err;
436 	dev_t dev;
437 
438 	sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);
439 
440 	/*
441 	 * Major numbers for the UBI character devices are allocated
442 	 * dynamically. Major numbers of volume character devices are
443 	 * equivalent to ones of the corresponding UBI character device. Minor
444 	 * numbers of UBI character devices are 0, while minor numbers of
445 	 * volume character devices start from 1. Thus, we allocate one major
446 	 * number and ubi->vtbl_slots + 1 minor numbers.
447 	 */
448 	err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
449 	if (err) {
450 		ubi_err(ubi, "cannot register UBI character devices");
451 		return err;
452 	}
453 
454 	ubi->dev.devt = dev;
455 
456 	ubi_assert(MINOR(dev) == 0);
457 	cdev_init(&ubi->cdev, &ubi_cdev_operations);
458 	dbg_gen("%s major is %u", ubi->ubi_name, MAJOR(dev));
459 	ubi->cdev.owner = THIS_MODULE;
460 
461 	dev_set_name(&ubi->dev, UBI_NAME_STR "%d", ubi->ubi_num);
462 	err = cdev_device_add(&ubi->cdev, &ubi->dev);
463 	if (err)
464 		goto out_unreg;
465 
466 	for (i = 0; i < ubi->vtbl_slots; i++)
467 		if (ubi->volumes[i]) {
468 			err = ubi_add_volume(ubi, ubi->volumes[i]);
469 			if (err) {
470 				ubi_err(ubi, "cannot add volume %d", i);
471 				goto out_volumes;
472 			}
473 		}
474 
475 	return 0;
476 
477 out_volumes:
478 	kill_volumes(ubi);
479 	cdev_device_del(&ubi->cdev, &ubi->dev);
480 out_unreg:
481 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
482 	ubi_err(ubi, "cannot initialize UBI %s, error %d",
483 		ubi->ubi_name, err);
484 	return err;
485 }
486 
487 /**
488  * uif_close - close user interfaces for an UBI device.
489  * @ubi: UBI device description object
490  *
491  * Note, since this function un-registers UBI volume device objects (@vol->dev),
492  * the memory allocated voe the volumes is freed as well (in the release
493  * function).
494  */
495 static void uif_close(struct ubi_device *ubi)
496 {
497 	kill_volumes(ubi);
498 	cdev_device_del(&ubi->cdev, &ubi->dev);
499 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
500 }
501 
502 /**
503  * ubi_free_volumes_from - free volumes from specific index.
504  * @ubi: UBI device description object
505  * @from: the start index used for volume free.
506  */
507 static void ubi_free_volumes_from(struct ubi_device *ubi, int from)
508 {
509 	int i;
510 
511 	for (i = from; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
512 		if (!ubi->volumes[i])
513 			continue;
514 		ubi_eba_replace_table(ubi->volumes[i], NULL);
515 		ubi_fastmap_destroy_checkmap(ubi->volumes[i]);
516 		kfree(ubi->volumes[i]);
517 		ubi->volumes[i] = NULL;
518 	}
519 }
520 
521 /**
522  * ubi_free_all_volumes - free all volumes.
523  * @ubi: UBI device description object
524  */
525 void ubi_free_all_volumes(struct ubi_device *ubi)
526 {
527 	ubi_free_volumes_from(ubi, 0);
528 }
529 
530 /**
531  * ubi_free_internal_volumes - free internal volumes.
532  * @ubi: UBI device description object
533  */
534 void ubi_free_internal_volumes(struct ubi_device *ubi)
535 {
536 	ubi_free_volumes_from(ubi, ubi->vtbl_slots);
537 }
538 
539 static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
540 {
541 	int limit, device_pebs;
542 	uint64_t device_size;
543 
544 	if (!max_beb_per1024) {
545 		/*
546 		 * Since max_beb_per1024 has not been set by the user in either
547 		 * the cmdline or Kconfig, use mtd_max_bad_blocks to set the
548 		 * limit if it is supported by the device.
549 		 */
550 		limit = mtd_max_bad_blocks(ubi->mtd, 0, ubi->mtd->size);
551 		if (limit < 0)
552 			return 0;
553 		return limit;
554 	}
555 
556 	/*
557 	 * Here we are using size of the entire flash chip and
558 	 * not just the MTD partition size because the maximum
559 	 * number of bad eraseblocks is a percentage of the
560 	 * whole device and bad eraseblocks are not fairly
561 	 * distributed over the flash chip. So the worst case
562 	 * is that all the bad eraseblocks of the chip are in
563 	 * the MTD partition we are attaching (ubi->mtd).
564 	 */
565 	device_size = mtd_get_device_size(ubi->mtd);
566 	device_pebs = mtd_div_by_eb(device_size, ubi->mtd);
567 	limit = mult_frac(device_pebs, max_beb_per1024, 1024);
568 
569 	/* Round it up */
570 	if (mult_frac(limit, 1024, max_beb_per1024) < device_pebs)
571 		limit += 1;
572 
573 	return limit;
574 }
575 
576 /**
577  * io_init - initialize I/O sub-system for a given UBI device.
578  * @ubi: UBI device description object
579  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
580  *
581  * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
582  * assumed:
583  *   o EC header is always at offset zero - this cannot be changed;
584  *   o VID header starts just after the EC header at the closest address
585  *     aligned to @io->hdrs_min_io_size;
586  *   o data starts just after the VID header at the closest address aligned to
587  *     @io->min_io_size
588  *
589  * This function returns zero in case of success and a negative error code in
590  * case of failure.
591  */
592 static int io_init(struct ubi_device *ubi, int max_beb_per1024)
593 {
594 	dbg_gen("sizeof(struct ubi_ainf_peb) %zu", sizeof(struct ubi_ainf_peb));
595 	dbg_gen("sizeof(struct ubi_wl_entry) %zu", sizeof(struct ubi_wl_entry));
596 
597 	if (ubi->mtd->numeraseregions != 0) {
598 		/*
599 		 * Some flashes have several erase regions. Different regions
600 		 * may have different eraseblock size and other
601 		 * characteristics. It looks like mostly multi-region flashes
602 		 * have one "main" region and one or more small regions to
603 		 * store boot loader code or boot parameters or whatever. I
604 		 * guess we should just pick the largest region. But this is
605 		 * not implemented.
606 		 */
607 		ubi_err(ubi, "multiple regions, not implemented");
608 		return -EINVAL;
609 	}
610 
611 	if (ubi->vid_hdr_offset < 0)
612 		return -EINVAL;
613 
614 	/*
615 	 * Note, in this implementation we support MTD devices with 0x7FFFFFFF
616 	 * physical eraseblocks maximum.
617 	 */
618 
619 	ubi->peb_size   = ubi->mtd->erasesize;
620 	ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
621 	ubi->flash_size = ubi->mtd->size;
622 
623 	if (mtd_can_have_bb(ubi->mtd)) {
624 		ubi->bad_allowed = 1;
625 		ubi->bad_peb_limit = get_bad_peb_limit(ubi, max_beb_per1024);
626 	}
627 
628 	if (ubi->mtd->type == MTD_NORFLASH)
629 		ubi->nor_flash = 1;
630 
631 	ubi->min_io_size = ubi->mtd->writesize;
632 	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
633 
634 	/*
635 	 * Make sure minimal I/O unit is power of 2. Note, there is no
636 	 * fundamental reason for this assumption. It is just an optimization
637 	 * which allows us to avoid costly division operations.
638 	 */
639 	if (!is_power_of_2(ubi->min_io_size)) {
640 		ubi_err(ubi, "min. I/O unit (%d) is not power of 2",
641 			ubi->min_io_size);
642 		return -EINVAL;
643 	}
644 
645 	ubi_assert(ubi->hdrs_min_io_size > 0);
646 	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
647 	ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
648 
649 	ubi->max_write_size = ubi->mtd->writebufsize;
650 	/*
651 	 * Maximum write size has to be greater or equivalent to min. I/O
652 	 * size, and be multiple of min. I/O size.
653 	 */
654 	if (ubi->max_write_size < ubi->min_io_size ||
655 	    ubi->max_write_size % ubi->min_io_size ||
656 	    !is_power_of_2(ubi->max_write_size)) {
657 		ubi_err(ubi, "bad write buffer size %d for %d min. I/O unit",
658 			ubi->max_write_size, ubi->min_io_size);
659 		return -EINVAL;
660 	}
661 
662 	/* Calculate default aligned sizes of EC and VID headers */
663 	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
664 	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
665 
666 	dbg_gen("min_io_size      %d", ubi->min_io_size);
667 	dbg_gen("max_write_size   %d", ubi->max_write_size);
668 	dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
669 	dbg_gen("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
670 	dbg_gen("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
671 
672 	if (ubi->vid_hdr_offset == 0)
673 		/* Default offset */
674 		ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
675 				      ubi->ec_hdr_alsize;
676 	else {
677 		ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
678 						~(ubi->hdrs_min_io_size - 1);
679 		ubi->vid_hdr_shift = ubi->vid_hdr_offset -
680 						ubi->vid_hdr_aloffset;
681 	}
682 
683 	/* Similar for the data offset */
684 	ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
685 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
686 
687 	dbg_gen("vid_hdr_offset   %d", ubi->vid_hdr_offset);
688 	dbg_gen("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
689 	dbg_gen("vid_hdr_shift    %d", ubi->vid_hdr_shift);
690 	dbg_gen("leb_start        %d", ubi->leb_start);
691 
692 	/* The shift must be aligned to 32-bit boundary */
693 	if (ubi->vid_hdr_shift % 4) {
694 		ubi_err(ubi, "unaligned VID header shift %d",
695 			ubi->vid_hdr_shift);
696 		return -EINVAL;
697 	}
698 
699 	/* Check sanity */
700 	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
701 	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
702 	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
703 	    ubi->leb_start & (ubi->min_io_size - 1)) {
704 		ubi_err(ubi, "bad VID header (%d) or data offsets (%d)",
705 			ubi->vid_hdr_offset, ubi->leb_start);
706 		return -EINVAL;
707 	}
708 
709 	/*
710 	 * Set maximum amount of physical erroneous eraseblocks to be 10%.
711 	 * Erroneous PEB are those which have read errors.
712 	 */
713 	ubi->max_erroneous = ubi->peb_count / 10;
714 	if (ubi->max_erroneous < 16)
715 		ubi->max_erroneous = 16;
716 	dbg_gen("max_erroneous    %d", ubi->max_erroneous);
717 
718 	/*
719 	 * It may happen that EC and VID headers are situated in one minimal
720 	 * I/O unit. In this case we can only accept this UBI image in
721 	 * read-only mode.
722 	 */
723 	if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
724 		ubi_warn(ubi, "EC and VID headers are in the same minimal I/O unit, switch to read-only mode");
725 		ubi->ro_mode = 1;
726 	}
727 
728 	ubi->leb_size = ubi->peb_size - ubi->leb_start;
729 
730 	if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
731 		ubi_msg(ubi, "MTD device %d is write-protected, attach in read-only mode",
732 			ubi->mtd->index);
733 		ubi->ro_mode = 1;
734 	}
735 
736 	/*
737 	 * Note, ideally, we have to initialize @ubi->bad_peb_count here. But
738 	 * unfortunately, MTD does not provide this information. We should loop
739 	 * over all physical eraseblocks and invoke mtd->block_is_bad() for
740 	 * each physical eraseblock. So, we leave @ubi->bad_peb_count
741 	 * uninitialized so far.
742 	 */
743 
744 	return 0;
745 }
746 
747 /**
748  * autoresize - re-size the volume which has the "auto-resize" flag set.
749  * @ubi: UBI device description object
750  * @vol_id: ID of the volume to re-size
751  *
752  * This function re-sizes the volume marked by the %UBI_VTBL_AUTORESIZE_FLG in
753  * the volume table to the largest possible size. See comments in ubi-header.h
754  * for more description of the flag. Returns zero in case of success and a
755  * negative error code in case of failure.
756  */
757 static int autoresize(struct ubi_device *ubi, int vol_id)
758 {
759 	struct ubi_volume_desc desc;
760 	struct ubi_volume *vol = ubi->volumes[vol_id];
761 	int err, old_reserved_pebs = vol->reserved_pebs;
762 
763 	if (ubi->ro_mode) {
764 		ubi_warn(ubi, "skip auto-resize because of R/O mode");
765 		return 0;
766 	}
767 
768 	/*
769 	 * Clear the auto-resize flag in the volume in-memory copy of the
770 	 * volume table, and 'ubi_resize_volume()' will propagate this change
771 	 * to the flash.
772 	 */
773 	ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;
774 
775 	if (ubi->avail_pebs == 0) {
776 		struct ubi_vtbl_record vtbl_rec;
777 
778 		/*
779 		 * No available PEBs to re-size the volume, clear the flag on
780 		 * flash and exit.
781 		 */
782 		vtbl_rec = ubi->vtbl[vol_id];
783 		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
784 		if (err)
785 			ubi_err(ubi, "cannot clean auto-resize flag for volume %d",
786 				vol_id);
787 	} else {
788 		desc.vol = vol;
789 		err = ubi_resize_volume(&desc,
790 					old_reserved_pebs + ubi->avail_pebs);
791 		if (err)
792 			ubi_err(ubi, "cannot auto-resize volume %d",
793 				vol_id);
794 	}
795 
796 	if (err)
797 		return err;
798 
799 	ubi_msg(ubi, "volume %d (\"%s\") re-sized from %d to %d LEBs",
800 		vol_id, vol->name, old_reserved_pebs, vol->reserved_pebs);
801 	return 0;
802 }
803 
804 /**
805  * ubi_attach_mtd_dev - attach an MTD device.
806  * @mtd: MTD device description object
807  * @ubi_num: number to assign to the new UBI device
808  * @vid_hdr_offset: VID header offset
809  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
810  * @disable_fm: whether disable fastmap
811  *
812  * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
813  * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
814  * which case this function finds a vacant device number and assigns it
815  * automatically. Returns the new UBI device number in case of success and a
816  * negative error code in case of failure.
817  *
818  * If @disable_fm is true, ubi doesn't create new fastmap even the module param
819  * 'fm_autoconvert' is set, and existed old fastmap will be destroyed after
820  * doing full scanning.
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, bool disable_fm)
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 || disable_fm) ? 1 : 0;
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, disable_fm ? 1 : 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 	err = uif_init(ubi);
984 	if (err)
985 		goto out_detach;
986 
987 	err = ubi_debugfs_init_dev(ubi);
988 	if (err)
989 		goto out_uif;
990 
991 	ubi->bgt_thread = kthread_create(ubi_thread, ubi, "%s", ubi->bgt_name);
992 	if (IS_ERR(ubi->bgt_thread)) {
993 		err = PTR_ERR(ubi->bgt_thread);
994 		ubi_err(ubi, "cannot spawn \"%s\", error %d",
995 			ubi->bgt_name, err);
996 		goto out_debugfs;
997 	}
998 
999 	ubi_msg(ubi, "attached mtd%d (name \"%s\", size %llu MiB)",
1000 		mtd->index, mtd->name, ubi->flash_size >> 20);
1001 	ubi_msg(ubi, "PEB size: %d bytes (%d KiB), LEB size: %d bytes",
1002 		ubi->peb_size, ubi->peb_size >> 10, ubi->leb_size);
1003 	ubi_msg(ubi, "min./max. I/O unit sizes: %d/%d, sub-page size %d",
1004 		ubi->min_io_size, ubi->max_write_size, ubi->hdrs_min_io_size);
1005 	ubi_msg(ubi, "VID header offset: %d (aligned %d), data offset: %d",
1006 		ubi->vid_hdr_offset, ubi->vid_hdr_aloffset, ubi->leb_start);
1007 	ubi_msg(ubi, "good PEBs: %d, bad PEBs: %d, corrupted PEBs: %d",
1008 		ubi->good_peb_count, ubi->bad_peb_count, ubi->corr_peb_count);
1009 	ubi_msg(ubi, "user volume: %d, internal volumes: %d, max. volumes count: %d",
1010 		ubi->vol_count - UBI_INT_VOL_COUNT, UBI_INT_VOL_COUNT,
1011 		ubi->vtbl_slots);
1012 	ubi_msg(ubi, "max/mean erase counter: %d/%d, WL threshold: %d, image sequence number: %u",
1013 		ubi->max_ec, ubi->mean_ec, CONFIG_MTD_UBI_WL_THRESHOLD,
1014 		ubi->image_seq);
1015 	ubi_msg(ubi, "available PEBs: %d, total reserved PEBs: %d, PEBs reserved for bad PEB handling: %d",
1016 		ubi->avail_pebs, ubi->rsvd_pebs, ubi->beb_rsvd_pebs);
1017 
1018 	/*
1019 	 * The below lock makes sure we do not race with 'ubi_thread()' which
1020 	 * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
1021 	 */
1022 	spin_lock(&ubi->wl_lock);
1023 	ubi->thread_enabled = 1;
1024 	wake_up_process(ubi->bgt_thread);
1025 	spin_unlock(&ubi->wl_lock);
1026 
1027 	ubi_devices[ubi_num] = ubi;
1028 	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
1029 	return ubi_num;
1030 
1031 out_debugfs:
1032 	ubi_debugfs_exit_dev(ubi);
1033 out_uif:
1034 	uif_close(ubi);
1035 out_detach:
1036 	ubi_wl_close(ubi);
1037 	ubi_free_all_volumes(ubi);
1038 	vfree(ubi->vtbl);
1039 out_free:
1040 	vfree(ubi->peb_buf);
1041 	vfree(ubi->fm_buf);
1042 	put_device(&ubi->dev);
1043 	return err;
1044 }
1045 
1046 /**
1047  * ubi_detach_mtd_dev - detach an MTD device.
1048  * @ubi_num: UBI device number to detach from
1049  * @anyway: detach MTD even if device reference count is not zero
1050  *
1051  * This function destroys an UBI device number @ubi_num and detaches the
1052  * underlying MTD device. Returns zero in case of success and %-EBUSY if the
1053  * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
1054  * exist.
1055  *
1056  * Note, the invocations of this function has to be serialized by the
1057  * @ubi_devices_mutex.
1058  */
1059 int ubi_detach_mtd_dev(int ubi_num, int anyway)
1060 {
1061 	struct ubi_device *ubi;
1062 
1063 	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
1064 		return -EINVAL;
1065 
1066 	ubi = ubi_get_device(ubi_num);
1067 	if (!ubi)
1068 		return -EINVAL;
1069 
1070 	spin_lock(&ubi_devices_lock);
1071 	put_device(&ubi->dev);
1072 	ubi->ref_count -= 1;
1073 	if (ubi->ref_count) {
1074 		if (!anyway) {
1075 			spin_unlock(&ubi_devices_lock);
1076 			return -EBUSY;
1077 		}
1078 		/* This may only happen if there is a bug */
1079 		ubi_err(ubi, "%s reference count %d, destroy anyway",
1080 			ubi->ubi_name, ubi->ref_count);
1081 	}
1082 	ubi_devices[ubi_num] = NULL;
1083 	spin_unlock(&ubi_devices_lock);
1084 
1085 	ubi_assert(ubi_num == ubi->ubi_num);
1086 	ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
1087 	ubi_msg(ubi, "detaching mtd%d", ubi->mtd->index);
1088 #ifdef CONFIG_MTD_UBI_FASTMAP
1089 	/* If we don't write a new fastmap at detach time we lose all
1090 	 * EC updates that have been made since the last written fastmap.
1091 	 * In case of fastmap debugging we omit the update to simulate an
1092 	 * unclean shutdown. */
1093 	if (!ubi_dbg_chk_fastmap(ubi))
1094 		ubi_update_fastmap(ubi);
1095 #endif
1096 	/*
1097 	 * Before freeing anything, we have to stop the background thread to
1098 	 * prevent it from doing anything on this device while we are freeing.
1099 	 */
1100 	if (ubi->bgt_thread)
1101 		kthread_stop(ubi->bgt_thread);
1102 
1103 #ifdef CONFIG_MTD_UBI_FASTMAP
1104 	cancel_work_sync(&ubi->fm_work);
1105 #endif
1106 	ubi_debugfs_exit_dev(ubi);
1107 	uif_close(ubi);
1108 
1109 	ubi_wl_close(ubi);
1110 	ubi_free_internal_volumes(ubi);
1111 	vfree(ubi->vtbl);
1112 	vfree(ubi->peb_buf);
1113 	vfree(ubi->fm_buf);
1114 	ubi_msg(ubi, "mtd%d is detached", ubi->mtd->index);
1115 	put_mtd_device(ubi->mtd);
1116 	put_device(&ubi->dev);
1117 	return 0;
1118 }
1119 
1120 /**
1121  * open_mtd_by_chdev - open an MTD device by its character device node path.
1122  * @mtd_dev: MTD character device node path
1123  *
1124  * This helper function opens an MTD device by its character node device path.
1125  * Returns MTD device description object in case of success and a negative
1126  * error code in case of failure.
1127  */
1128 static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
1129 {
1130 	int err, minor;
1131 	struct path path;
1132 	struct kstat stat;
1133 
1134 	/* Probably this is an MTD character device node path */
1135 	err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
1136 	if (err)
1137 		return ERR_PTR(err);
1138 
1139 	err = vfs_getattr(&path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
1140 	path_put(&path);
1141 	if (err)
1142 		return ERR_PTR(err);
1143 
1144 	/* MTD device number is defined by the major / minor numbers */
1145 	if (MAJOR(stat.rdev) != MTD_CHAR_MAJOR || !S_ISCHR(stat.mode))
1146 		return ERR_PTR(-EINVAL);
1147 
1148 	minor = MINOR(stat.rdev);
1149 
1150 	if (minor & 1)
1151 		/*
1152 		 * Just do not think the "/dev/mtdrX" devices support is need,
1153 		 * so do not support them to avoid doing extra work.
1154 		 */
1155 		return ERR_PTR(-EINVAL);
1156 
1157 	return get_mtd_device(NULL, minor / 2);
1158 }
1159 
1160 /**
1161  * open_mtd_device - open MTD device by name, character device path, or number.
1162  * @mtd_dev: name, character device node path, or MTD device device number
1163  *
1164  * This function tries to open and MTD device described by @mtd_dev string,
1165  * which is first treated as ASCII MTD device number, and if it is not true, it
1166  * is treated as MTD device name, and if that is also not true, it is treated
1167  * as MTD character device node path. Returns MTD device description object in
1168  * case of success and a negative error code in case of failure.
1169  */
1170 static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
1171 {
1172 	struct mtd_info *mtd;
1173 	int mtd_num;
1174 	char *endp;
1175 
1176 	mtd_num = simple_strtoul(mtd_dev, &endp, 0);
1177 	if (*endp != '\0' || mtd_dev == endp) {
1178 		/*
1179 		 * This does not look like an ASCII integer, probably this is
1180 		 * MTD device name.
1181 		 */
1182 		mtd = get_mtd_device_nm(mtd_dev);
1183 		if (PTR_ERR(mtd) == -ENODEV)
1184 			/* Probably this is an MTD character device node path */
1185 			mtd = open_mtd_by_chdev(mtd_dev);
1186 	} else
1187 		mtd = get_mtd_device(NULL, mtd_num);
1188 
1189 	return mtd;
1190 }
1191 
1192 static int __init ubi_init(void)
1193 {
1194 	int err, i, k;
1195 
1196 	/* Ensure that EC and VID headers have correct size */
1197 	BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
1198 	BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);
1199 
1200 	if (mtd_devs > UBI_MAX_DEVICES) {
1201 		pr_err("UBI error: too many MTD devices, maximum is %d\n",
1202 		       UBI_MAX_DEVICES);
1203 		return -EINVAL;
1204 	}
1205 
1206 	/* Create base sysfs directory and sysfs files */
1207 	err = class_register(&ubi_class);
1208 	if (err < 0)
1209 		return err;
1210 
1211 	err = misc_register(&ubi_ctrl_cdev);
1212 	if (err) {
1213 		pr_err("UBI error: cannot register device\n");
1214 		goto out;
1215 	}
1216 
1217 	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
1218 					      sizeof(struct ubi_wl_entry),
1219 					      0, 0, NULL);
1220 	if (!ubi_wl_entry_slab) {
1221 		err = -ENOMEM;
1222 		goto out_dev_unreg;
1223 	}
1224 
1225 	err = ubi_debugfs_init();
1226 	if (err)
1227 		goto out_slab;
1228 
1229 
1230 	/* Attach MTD devices */
1231 	for (i = 0; i < mtd_devs; i++) {
1232 		struct mtd_dev_param *p = &mtd_dev_param[i];
1233 		struct mtd_info *mtd;
1234 
1235 		cond_resched();
1236 
1237 		mtd = open_mtd_device(p->name);
1238 		if (IS_ERR(mtd)) {
1239 			err = PTR_ERR(mtd);
1240 			pr_err("UBI error: cannot open mtd %s, error %d\n",
1241 			       p->name, err);
1242 			/* See comment below re-ubi_is_module(). */
1243 			if (ubi_is_module())
1244 				goto out_detach;
1245 			continue;
1246 		}
1247 
1248 		mutex_lock(&ubi_devices_mutex);
1249 		err = ubi_attach_mtd_dev(mtd, p->ubi_num,
1250 					 p->vid_hdr_offs, p->max_beb_per1024,
1251 					 false);
1252 		mutex_unlock(&ubi_devices_mutex);
1253 		if (err < 0) {
1254 			pr_err("UBI error: cannot attach mtd%d\n",
1255 			       mtd->index);
1256 			put_mtd_device(mtd);
1257 
1258 			/*
1259 			 * Originally UBI stopped initializing on any error.
1260 			 * However, later on it was found out that this
1261 			 * behavior is not very good when UBI is compiled into
1262 			 * the kernel and the MTD devices to attach are passed
1263 			 * through the command line. Indeed, UBI failure
1264 			 * stopped whole boot sequence.
1265 			 *
1266 			 * To fix this, we changed the behavior for the
1267 			 * non-module case, but preserved the old behavior for
1268 			 * the module case, just for compatibility. This is a
1269 			 * little inconsistent, though.
1270 			 */
1271 			if (ubi_is_module())
1272 				goto out_detach;
1273 		}
1274 	}
1275 
1276 	err = ubiblock_init();
1277 	if (err) {
1278 		pr_err("UBI error: block: cannot initialize, error %d\n", err);
1279 
1280 		/* See comment above re-ubi_is_module(). */
1281 		if (ubi_is_module())
1282 			goto out_detach;
1283 	}
1284 
1285 	return 0;
1286 
1287 out_detach:
1288 	for (k = 0; k < i; k++)
1289 		if (ubi_devices[k]) {
1290 			mutex_lock(&ubi_devices_mutex);
1291 			ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
1292 			mutex_unlock(&ubi_devices_mutex);
1293 		}
1294 	ubi_debugfs_exit();
1295 out_slab:
1296 	kmem_cache_destroy(ubi_wl_entry_slab);
1297 out_dev_unreg:
1298 	misc_deregister(&ubi_ctrl_cdev);
1299 out:
1300 	class_unregister(&ubi_class);
1301 	pr_err("UBI error: cannot initialize UBI, error %d\n", err);
1302 	return err;
1303 }
1304 late_initcall(ubi_init);
1305 
1306 static void __exit ubi_exit(void)
1307 {
1308 	int i;
1309 
1310 	ubiblock_exit();
1311 
1312 	for (i = 0; i < UBI_MAX_DEVICES; i++)
1313 		if (ubi_devices[i]) {
1314 			mutex_lock(&ubi_devices_mutex);
1315 			ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
1316 			mutex_unlock(&ubi_devices_mutex);
1317 		}
1318 	ubi_debugfs_exit();
1319 	kmem_cache_destroy(ubi_wl_entry_slab);
1320 	misc_deregister(&ubi_ctrl_cdev);
1321 	class_unregister(&ubi_class);
1322 }
1323 module_exit(ubi_exit);
1324 
1325 /**
1326  * bytes_str_to_int - convert a number of bytes string into an integer.
1327  * @str: the string to convert
1328  *
1329  * This function returns positive resulting integer in case of success and a
1330  * negative error code in case of failure.
1331  */
1332 static int bytes_str_to_int(const char *str)
1333 {
1334 	char *endp;
1335 	unsigned long result;
1336 
1337 	result = simple_strtoul(str, &endp, 0);
1338 	if (str == endp || result >= INT_MAX) {
1339 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1340 		return -EINVAL;
1341 	}
1342 
1343 	switch (*endp) {
1344 	case 'G':
1345 		result *= 1024;
1346 		fallthrough;
1347 	case 'M':
1348 		result *= 1024;
1349 		fallthrough;
1350 	case 'K':
1351 		result *= 1024;
1352 		break;
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