xref: /openbmc/linux/drivers/mtd/ubi/build.c (revision 54d8c1d3)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) International Business Machines Corp., 2006
4  * Copyright (c) Nokia Corporation, 2007
5  *
6  * Author: Artem Bityutskiy (Битюцкий Артём),
7  *         Frank Haverkamp
8  */
9 
10 /*
11  * This file includes UBI initialization and building of UBI devices.
12  *
13  * When UBI is initialized, it attaches all the MTD devices specified as the
14  * module load parameters or the kernel boot parameters. If MTD devices were
15  * specified, UBI does not attach any MTD device, but it is possible to do
16  * later using the "UBI control device".
17  */
18 
19 #include <linux/err.h>
20 #include <linux/module.h>
21 #include <linux/moduleparam.h>
22 #include <linux/stringify.h>
23 #include <linux/namei.h>
24 #include <linux/stat.h>
25 #include <linux/miscdevice.h>
26 #include <linux/mtd/partitions.h>
27 #include <linux/log2.h>
28 #include <linux/kthread.h>
29 #include <linux/kernel.h>
30 #include <linux/slab.h>
31 #include <linux/major.h>
32 #include "ubi.h"
33 
34 /* Maximum length of the 'mtd=' parameter */
35 #define MTD_PARAM_LEN_MAX 64
36 
37 /* Maximum number of comma-separated items in the 'mtd=' parameter */
38 #define MTD_PARAM_MAX_COUNT 5
39 
40 /* Maximum value for the number of bad PEBs per 1024 PEBs */
41 #define MAX_MTD_UBI_BEB_LIMIT 768
42 
43 #ifdef CONFIG_MTD_UBI_MODULE
44 #define ubi_is_module() 1
45 #else
46 #define ubi_is_module() 0
47 #endif
48 
49 /**
50  * struct mtd_dev_param - MTD device parameter description data structure.
51  * @name: MTD character device node path, MTD device name, or MTD device number
52  *        string
53  * @ubi_num: UBI number
54  * @vid_hdr_offs: VID header offset
55  * @max_beb_per1024: maximum expected number of bad PEBs per 1024 PEBs
56  * @enable_fm: enable fastmap when value is non-zero
57  */
58 struct mtd_dev_param {
59 	char name[MTD_PARAM_LEN_MAX];
60 	int ubi_num;
61 	int vid_hdr_offs;
62 	int max_beb_per1024;
63 	int enable_fm;
64 };
65 
66 /* Numbers of elements set in the @mtd_dev_param array */
67 static int mtd_devs;
68 
69 /* MTD devices specification parameters */
70 static struct mtd_dev_param mtd_dev_param[UBI_MAX_DEVICES];
71 #ifdef CONFIG_MTD_UBI_FASTMAP
72 /* UBI module parameter to enable fastmap automatically on non-fastmap images */
73 static bool fm_autoconvert;
74 static bool fm_debug;
75 #endif
76 
77 /* Slab cache for wear-leveling entries */
78 struct kmem_cache *ubi_wl_entry_slab;
79 
80 /* UBI control character device */
81 static struct miscdevice ubi_ctrl_cdev = {
82 	.minor = MISC_DYNAMIC_MINOR,
83 	.name = "ubi_ctrl",
84 	.fops = &ubi_ctrl_cdev_operations,
85 };
86 
87 /* All UBI devices in system */
88 static struct ubi_device *ubi_devices[UBI_MAX_DEVICES];
89 
90 /* Serializes UBI devices creations and removals */
91 DEFINE_MUTEX(ubi_devices_mutex);
92 
93 /* Protects @ubi_devices and @ubi->ref_count */
94 static DEFINE_SPINLOCK(ubi_devices_lock);
95 
96 /* "Show" method for files in '/<sysfs>/class/ubi/' */
97 /* UBI version attribute ('/<sysfs>/class/ubi/version') */
98 static ssize_t version_show(const struct class *class, const struct class_attribute *attr,
99 			    char *buf)
100 {
101 	return sprintf(buf, "%d\n", UBI_VERSION);
102 }
103 static CLASS_ATTR_RO(version);
104 
105 static struct attribute *ubi_class_attrs[] = {
106 	&class_attr_version.attr,
107 	NULL,
108 };
109 ATTRIBUTE_GROUPS(ubi_class);
110 
111 /* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
112 struct class ubi_class = {
113 	.name		= UBI_NAME_STR,
114 	.class_groups	= ubi_class_groups,
115 };
116 
117 static ssize_t dev_attribute_show(struct device *dev,
118 				  struct device_attribute *attr, char *buf);
119 
120 /* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
121 static struct device_attribute dev_eraseblock_size =
122 	__ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
123 static struct device_attribute dev_avail_eraseblocks =
124 	__ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
125 static struct device_attribute dev_total_eraseblocks =
126 	__ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
127 static struct device_attribute dev_volumes_count =
128 	__ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
129 static struct device_attribute dev_max_ec =
130 	__ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
131 static struct device_attribute dev_reserved_for_bad =
132 	__ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
133 static struct device_attribute dev_bad_peb_count =
134 	__ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
135 static struct device_attribute dev_max_vol_count =
136 	__ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
137 static struct device_attribute dev_min_io_size =
138 	__ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
139 static struct device_attribute dev_bgt_enabled =
140 	__ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);
141 static struct device_attribute dev_mtd_num =
142 	__ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
143 static struct device_attribute dev_ro_mode =
144 	__ATTR(ro_mode, S_IRUGO, dev_attribute_show, NULL);
145 
146 /**
147  * ubi_volume_notify - send a volume change notification.
148  * @ubi: UBI device description object
149  * @vol: volume description object of the changed volume
150  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
151  *
152  * This is a helper function which notifies all subscribers about a volume
153  * change event (creation, removal, re-sizing, re-naming, updating). Returns
154  * zero in case of success and a negative error code in case of failure.
155  */
156 int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
157 {
158 	int ret;
159 	struct ubi_notification nt;
160 
161 	ubi_do_get_device_info(ubi, &nt.di);
162 	ubi_do_get_volume_info(ubi, vol, &nt.vi);
163 
164 	switch (ntype) {
165 	case UBI_VOLUME_ADDED:
166 	case UBI_VOLUME_REMOVED:
167 	case UBI_VOLUME_RESIZED:
168 	case UBI_VOLUME_RENAMED:
169 		ret = ubi_update_fastmap(ubi);
170 		if (ret)
171 			ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
172 	}
173 
174 	return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
175 }
176 
177 /**
178  * ubi_notify_all - send a notification to all volumes.
179  * @ubi: UBI device description object
180  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
181  * @nb: the notifier to call
182  *
183  * This function walks all volumes of UBI device @ubi and sends the @ntype
184  * notification for each volume. If @nb is %NULL, then all registered notifiers
185  * are called, otherwise only the @nb notifier is called. Returns the number of
186  * sent notifications.
187  */
188 int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
189 {
190 	struct ubi_notification nt;
191 	int i, count = 0;
192 
193 	ubi_do_get_device_info(ubi, &nt.di);
194 
195 	mutex_lock(&ubi->device_mutex);
196 	for (i = 0; i < ubi->vtbl_slots; i++) {
197 		/*
198 		 * Since the @ubi->device is locked, and we are not going to
199 		 * change @ubi->volumes, we do not have to lock
200 		 * @ubi->volumes_lock.
201 		 */
202 		if (!ubi->volumes[i])
203 			continue;
204 
205 		ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
206 		if (nb)
207 			nb->notifier_call(nb, ntype, &nt);
208 		else
209 			blocking_notifier_call_chain(&ubi_notifiers, ntype,
210 						     &nt);
211 		count += 1;
212 	}
213 	mutex_unlock(&ubi->device_mutex);
214 
215 	return count;
216 }
217 
218 /**
219  * ubi_enumerate_volumes - send "add" notification for all existing volumes.
220  * @nb: the notifier to call
221  *
222  * This function walks all UBI devices and volumes and sends the
223  * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
224  * registered notifiers are called, otherwise only the @nb notifier is called.
225  * Returns the number of sent notifications.
226  */
227 int ubi_enumerate_volumes(struct notifier_block *nb)
228 {
229 	int i, count = 0;
230 
231 	/*
232 	 * Since the @ubi_devices_mutex is locked, and we are not going to
233 	 * change @ubi_devices, we do not have to lock @ubi_devices_lock.
234 	 */
235 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
236 		struct ubi_device *ubi = ubi_devices[i];
237 
238 		if (!ubi)
239 			continue;
240 		count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
241 	}
242 
243 	return count;
244 }
245 
246 /**
247  * ubi_get_device - get UBI device.
248  * @ubi_num: UBI device number
249  *
250  * This function returns UBI device description object for UBI device number
251  * @ubi_num, or %NULL if the device does not exist. This function increases the
252  * device reference count to prevent removal of the device. In other words, the
253  * device cannot be removed if its reference count is not zero.
254  */
255 struct ubi_device *ubi_get_device(int ubi_num)
256 {
257 	struct ubi_device *ubi;
258 
259 	spin_lock(&ubi_devices_lock);
260 	ubi = ubi_devices[ubi_num];
261 	if (ubi) {
262 		ubi_assert(ubi->ref_count >= 0);
263 		ubi->ref_count += 1;
264 		get_device(&ubi->dev);
265 	}
266 	spin_unlock(&ubi_devices_lock);
267 
268 	return ubi;
269 }
270 
271 /**
272  * ubi_put_device - drop an UBI device reference.
273  * @ubi: UBI device description object
274  */
275 void ubi_put_device(struct ubi_device *ubi)
276 {
277 	spin_lock(&ubi_devices_lock);
278 	ubi->ref_count -= 1;
279 	put_device(&ubi->dev);
280 	spin_unlock(&ubi_devices_lock);
281 }
282 
283 /**
284  * ubi_get_by_major - get UBI device by character device major number.
285  * @major: major number
286  *
287  * This function is similar to 'ubi_get_device()', but it searches the device
288  * by its major number.
289  */
290 struct ubi_device *ubi_get_by_major(int major)
291 {
292 	int i;
293 	struct ubi_device *ubi;
294 
295 	spin_lock(&ubi_devices_lock);
296 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
297 		ubi = ubi_devices[i];
298 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
299 			ubi_assert(ubi->ref_count >= 0);
300 			ubi->ref_count += 1;
301 			get_device(&ubi->dev);
302 			spin_unlock(&ubi_devices_lock);
303 			return ubi;
304 		}
305 	}
306 	spin_unlock(&ubi_devices_lock);
307 
308 	return NULL;
309 }
310 
311 /**
312  * ubi_major2num - get UBI device number by character device major number.
313  * @major: major number
314  *
315  * This function searches UBI device number object by its major number. If UBI
316  * device was not found, this function returns -ENODEV, otherwise the UBI device
317  * number is returned.
318  */
319 int ubi_major2num(int major)
320 {
321 	int i, ubi_num = -ENODEV;
322 
323 	spin_lock(&ubi_devices_lock);
324 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
325 		struct ubi_device *ubi = ubi_devices[i];
326 
327 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
328 			ubi_num = ubi->ubi_num;
329 			break;
330 		}
331 	}
332 	spin_unlock(&ubi_devices_lock);
333 
334 	return ubi_num;
335 }
336 
337 /* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
338 static ssize_t dev_attribute_show(struct device *dev,
339 				  struct device_attribute *attr, char *buf)
340 {
341 	ssize_t ret;
342 	struct ubi_device *ubi;
343 
344 	/*
345 	 * The below code looks weird, but it actually makes sense. We get the
346 	 * UBI device reference from the contained 'struct ubi_device'. But it
347 	 * is unclear if the device was removed or not yet. Indeed, if the
348 	 * device was removed before we increased its reference count,
349 	 * 'ubi_get_device()' will return -ENODEV and we fail.
350 	 *
351 	 * Remember, 'struct ubi_device' is freed in the release function, so
352 	 * we still can use 'ubi->ubi_num'.
353 	 */
354 	ubi = container_of(dev, struct ubi_device, dev);
355 
356 	if (attr == &dev_eraseblock_size)
357 		ret = sprintf(buf, "%d\n", ubi->leb_size);
358 	else if (attr == &dev_avail_eraseblocks)
359 		ret = sprintf(buf, "%d\n", ubi->avail_pebs);
360 	else if (attr == &dev_total_eraseblocks)
361 		ret = sprintf(buf, "%d\n", ubi->good_peb_count);
362 	else if (attr == &dev_volumes_count)
363 		ret = sprintf(buf, "%d\n", ubi->vol_count - UBI_INT_VOL_COUNT);
364 	else if (attr == &dev_max_ec)
365 		ret = sprintf(buf, "%d\n", ubi->max_ec);
366 	else if (attr == &dev_reserved_for_bad)
367 		ret = sprintf(buf, "%d\n", ubi->beb_rsvd_pebs);
368 	else if (attr == &dev_bad_peb_count)
369 		ret = sprintf(buf, "%d\n", ubi->bad_peb_count);
370 	else if (attr == &dev_max_vol_count)
371 		ret = sprintf(buf, "%d\n", ubi->vtbl_slots);
372 	else if (attr == &dev_min_io_size)
373 		ret = sprintf(buf, "%d\n", ubi->min_io_size);
374 	else if (attr == &dev_bgt_enabled)
375 		ret = sprintf(buf, "%d\n", ubi->thread_enabled);
376 	else if (attr == &dev_mtd_num)
377 		ret = sprintf(buf, "%d\n", ubi->mtd->index);
378 	else if (attr == &dev_ro_mode)
379 		ret = sprintf(buf, "%d\n", ubi->ro_mode);
380 	else
381 		ret = -EINVAL;
382 
383 	return ret;
384 }
385 
386 static struct attribute *ubi_dev_attrs[] = {
387 	&dev_eraseblock_size.attr,
388 	&dev_avail_eraseblocks.attr,
389 	&dev_total_eraseblocks.attr,
390 	&dev_volumes_count.attr,
391 	&dev_max_ec.attr,
392 	&dev_reserved_for_bad.attr,
393 	&dev_bad_peb_count.attr,
394 	&dev_max_vol_count.attr,
395 	&dev_min_io_size.attr,
396 	&dev_bgt_enabled.attr,
397 	&dev_mtd_num.attr,
398 	&dev_ro_mode.attr,
399 	NULL
400 };
401 ATTRIBUTE_GROUPS(ubi_dev);
402 
403 static void dev_release(struct device *dev)
404 {
405 	struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);
406 
407 	kfree(ubi);
408 }
409 
410 /**
411  * kill_volumes - destroy all user volumes.
412  * @ubi: UBI device description object
413  */
414 static void kill_volumes(struct ubi_device *ubi)
415 {
416 	int i;
417 
418 	for (i = 0; i < ubi->vtbl_slots; i++)
419 		if (ubi->volumes[i])
420 			ubi_free_volume(ubi, ubi->volumes[i]);
421 }
422 
423 /**
424  * uif_init - initialize user interfaces for an UBI device.
425  * @ubi: UBI device description object
426  *
427  * This function initializes various user interfaces for an UBI device. If the
428  * initialization fails at an early stage, this function frees all the
429  * resources it allocated, returns an error.
430  *
431  * This function returns zero in case of success and a negative error code in
432  * case of failure.
433  */
434 static int uif_init(struct ubi_device *ubi)
435 {
436 	int i, err;
437 	dev_t dev;
438 
439 	sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);
440 
441 	/*
442 	 * Major numbers for the UBI character devices are allocated
443 	 * dynamically. Major numbers of volume character devices are
444 	 * equivalent to ones of the corresponding UBI character device. Minor
445 	 * numbers of UBI character devices are 0, while minor numbers of
446 	 * volume character devices start from 1. Thus, we allocate one major
447 	 * number and ubi->vtbl_slots + 1 minor numbers.
448 	 */
449 	err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
450 	if (err) {
451 		ubi_err(ubi, "cannot register UBI character devices");
452 		return err;
453 	}
454 
455 	ubi->dev.devt = dev;
456 
457 	ubi_assert(MINOR(dev) == 0);
458 	cdev_init(&ubi->cdev, &ubi_cdev_operations);
459 	dbg_gen("%s major is %u", ubi->ubi_name, MAJOR(dev));
460 	ubi->cdev.owner = THIS_MODULE;
461 
462 	dev_set_name(&ubi->dev, UBI_NAME_STR "%d", ubi->ubi_num);
463 	err = cdev_device_add(&ubi->cdev, &ubi->dev);
464 	if (err)
465 		goto out_unreg;
466 
467 	for (i = 0; i < ubi->vtbl_slots; i++)
468 		if (ubi->volumes[i]) {
469 			err = ubi_add_volume(ubi, ubi->volumes[i]);
470 			if (err) {
471 				ubi_err(ubi, "cannot add volume %d", i);
472 				ubi->volumes[i] = NULL;
473 				goto out_volumes;
474 			}
475 		}
476 
477 	return 0;
478 
479 out_volumes:
480 	kill_volumes(ubi);
481 	cdev_device_del(&ubi->cdev, &ubi->dev);
482 out_unreg:
483 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
484 	ubi_err(ubi, "cannot initialize UBI %s, error %d",
485 		ubi->ubi_name, err);
486 	return err;
487 }
488 
489 /**
490  * uif_close - close user interfaces for an UBI device.
491  * @ubi: UBI device description object
492  *
493  * Note, since this function un-registers UBI volume device objects (@vol->dev),
494  * the memory allocated voe the volumes is freed as well (in the release
495  * function).
496  */
497 static void uif_close(struct ubi_device *ubi)
498 {
499 	kill_volumes(ubi);
500 	cdev_device_del(&ubi->cdev, &ubi->dev);
501 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
502 }
503 
504 /**
505  * ubi_free_volumes_from - free volumes from specific index.
506  * @ubi: UBI device description object
507  * @from: the start index used for volume free.
508  */
509 static void ubi_free_volumes_from(struct ubi_device *ubi, int from)
510 {
511 	int i;
512 
513 	for (i = from; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
514 		if (!ubi->volumes[i])
515 			continue;
516 		ubi_eba_replace_table(ubi->volumes[i], NULL);
517 		ubi_fastmap_destroy_checkmap(ubi->volumes[i]);
518 		kfree(ubi->volumes[i]);
519 		ubi->volumes[i] = NULL;
520 	}
521 }
522 
523 /**
524  * ubi_free_all_volumes - free all volumes.
525  * @ubi: UBI device description object
526  */
527 void ubi_free_all_volumes(struct ubi_device *ubi)
528 {
529 	ubi_free_volumes_from(ubi, 0);
530 }
531 
532 /**
533  * ubi_free_internal_volumes - free internal volumes.
534  * @ubi: UBI device description object
535  */
536 void ubi_free_internal_volumes(struct ubi_device *ubi)
537 {
538 	ubi_free_volumes_from(ubi, ubi->vtbl_slots);
539 }
540 
541 static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
542 {
543 	int limit, device_pebs;
544 	uint64_t device_size;
545 
546 	if (!max_beb_per1024) {
547 		/*
548 		 * Since max_beb_per1024 has not been set by the user in either
549 		 * the cmdline or Kconfig, use mtd_max_bad_blocks to set the
550 		 * limit if it is supported by the device.
551 		 */
552 		limit = mtd_max_bad_blocks(ubi->mtd, 0, ubi->mtd->size);
553 		if (limit < 0)
554 			return 0;
555 		return limit;
556 	}
557 
558 	/*
559 	 * Here we are using size of the entire flash chip and
560 	 * not just the MTD partition size because the maximum
561 	 * number of bad eraseblocks is a percentage of the
562 	 * whole device and bad eraseblocks are not fairly
563 	 * distributed over the flash chip. So the worst case
564 	 * is that all the bad eraseblocks of the chip are in
565 	 * the MTD partition we are attaching (ubi->mtd).
566 	 */
567 	device_size = mtd_get_device_size(ubi->mtd);
568 	device_pebs = mtd_div_by_eb(device_size, ubi->mtd);
569 	limit = mult_frac(device_pebs, max_beb_per1024, 1024);
570 
571 	/* Round it up */
572 	if (mult_frac(limit, 1024, max_beb_per1024) < device_pebs)
573 		limit += 1;
574 
575 	return limit;
576 }
577 
578 /**
579  * io_init - initialize I/O sub-system for a given UBI device.
580  * @ubi: UBI device description object
581  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
582  *
583  * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
584  * assumed:
585  *   o EC header is always at offset zero - this cannot be changed;
586  *   o VID header starts just after the EC header at the closest address
587  *     aligned to @io->hdrs_min_io_size;
588  *   o data starts just after the VID header at the closest address aligned to
589  *     @io->min_io_size
590  *
591  * This function returns zero in case of success and a negative error code in
592  * case of failure.
593  */
594 static int io_init(struct ubi_device *ubi, int max_beb_per1024)
595 {
596 	dbg_gen("sizeof(struct ubi_ainf_peb) %zu", sizeof(struct ubi_ainf_peb));
597 	dbg_gen("sizeof(struct ubi_wl_entry) %zu", sizeof(struct ubi_wl_entry));
598 
599 	if (ubi->mtd->numeraseregions != 0) {
600 		/*
601 		 * Some flashes have several erase regions. Different regions
602 		 * may have different eraseblock size and other
603 		 * characteristics. It looks like mostly multi-region flashes
604 		 * have one "main" region and one or more small regions to
605 		 * store boot loader code or boot parameters or whatever. I
606 		 * guess we should just pick the largest region. But this is
607 		 * not implemented.
608 		 */
609 		ubi_err(ubi, "multiple regions, not implemented");
610 		return -EINVAL;
611 	}
612 
613 	if (ubi->vid_hdr_offset < 0)
614 		return -EINVAL;
615 
616 	/*
617 	 * Note, in this implementation we support MTD devices with 0x7FFFFFFF
618 	 * physical eraseblocks maximum.
619 	 */
620 
621 	ubi->peb_size   = ubi->mtd->erasesize;
622 	ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
623 	ubi->flash_size = ubi->mtd->size;
624 
625 	if (mtd_can_have_bb(ubi->mtd)) {
626 		ubi->bad_allowed = 1;
627 		ubi->bad_peb_limit = get_bad_peb_limit(ubi, max_beb_per1024);
628 	}
629 
630 	if (ubi->mtd->type == MTD_NORFLASH)
631 		ubi->nor_flash = 1;
632 
633 	ubi->min_io_size = ubi->mtd->writesize;
634 	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
635 
636 	/*
637 	 * Make sure minimal I/O unit is power of 2. Note, there is no
638 	 * fundamental reason for this assumption. It is just an optimization
639 	 * which allows us to avoid costly division operations.
640 	 */
641 	if (!is_power_of_2(ubi->min_io_size)) {
642 		ubi_err(ubi, "min. I/O unit (%d) is not power of 2",
643 			ubi->min_io_size);
644 		return -EINVAL;
645 	}
646 
647 	ubi_assert(ubi->hdrs_min_io_size > 0);
648 	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
649 	ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
650 
651 	ubi->max_write_size = ubi->mtd->writebufsize;
652 	/*
653 	 * Maximum write size has to be greater or equivalent to min. I/O
654 	 * size, and be multiple of min. I/O size.
655 	 */
656 	if (ubi->max_write_size < ubi->min_io_size ||
657 	    ubi->max_write_size % ubi->min_io_size ||
658 	    !is_power_of_2(ubi->max_write_size)) {
659 		ubi_err(ubi, "bad write buffer size %d for %d min. I/O unit",
660 			ubi->max_write_size, ubi->min_io_size);
661 		return -EINVAL;
662 	}
663 
664 	/* Calculate default aligned sizes of EC and VID headers */
665 	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
666 	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
667 
668 	dbg_gen("min_io_size      %d", ubi->min_io_size);
669 	dbg_gen("max_write_size   %d", ubi->max_write_size);
670 	dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
671 	dbg_gen("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
672 	dbg_gen("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
673 
674 	if (ubi->vid_hdr_offset == 0)
675 		/* Default offset */
676 		ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
677 				      ubi->ec_hdr_alsize;
678 	else {
679 		ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
680 						~(ubi->hdrs_min_io_size - 1);
681 		ubi->vid_hdr_shift = ubi->vid_hdr_offset -
682 						ubi->vid_hdr_aloffset;
683 	}
684 
685 	/*
686 	 * Memory allocation for VID header is ubi->vid_hdr_alsize
687 	 * which is described in comments in io.c.
688 	 * Make sure VID header shift + UBI_VID_HDR_SIZE not exceeds
689 	 * ubi->vid_hdr_alsize, so that all vid header operations
690 	 * won't access memory out of bounds.
691 	 */
692 	if ((ubi->vid_hdr_shift + UBI_VID_HDR_SIZE) > ubi->vid_hdr_alsize) {
693 		ubi_err(ubi, "Invalid VID header offset %d, VID header shift(%d)"
694 			" + VID header size(%zu) > VID header aligned size(%d).",
695 			ubi->vid_hdr_offset, ubi->vid_hdr_shift,
696 			UBI_VID_HDR_SIZE, ubi->vid_hdr_alsize);
697 		return -EINVAL;
698 	}
699 
700 	/* Similar for the data offset */
701 	ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
702 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
703 
704 	dbg_gen("vid_hdr_offset   %d", ubi->vid_hdr_offset);
705 	dbg_gen("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
706 	dbg_gen("vid_hdr_shift    %d", ubi->vid_hdr_shift);
707 	dbg_gen("leb_start        %d", ubi->leb_start);
708 
709 	/* The shift must be aligned to 32-bit boundary */
710 	if (ubi->vid_hdr_shift % 4) {
711 		ubi_err(ubi, "unaligned VID header shift %d",
712 			ubi->vid_hdr_shift);
713 		return -EINVAL;
714 	}
715 
716 	/* Check sanity */
717 	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
718 	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
719 	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
720 	    ubi->leb_start & (ubi->min_io_size - 1)) {
721 		ubi_err(ubi, "bad VID header (%d) or data offsets (%d)",
722 			ubi->vid_hdr_offset, ubi->leb_start);
723 		return -EINVAL;
724 	}
725 
726 	/*
727 	 * Set maximum amount of physical erroneous eraseblocks to be 10%.
728 	 * Erroneous PEB are those which have read errors.
729 	 */
730 	ubi->max_erroneous = ubi->peb_count / 10;
731 	if (ubi->max_erroneous < 16)
732 		ubi->max_erroneous = 16;
733 	dbg_gen("max_erroneous    %d", ubi->max_erroneous);
734 
735 	/*
736 	 * It may happen that EC and VID headers are situated in one minimal
737 	 * I/O unit. In this case we can only accept this UBI image in
738 	 * read-only mode.
739 	 */
740 	if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
741 		ubi_warn(ubi, "EC and VID headers are in the same minimal I/O unit, switch to read-only mode");
742 		ubi->ro_mode = 1;
743 	}
744 
745 	ubi->leb_size = ubi->peb_size - ubi->leb_start;
746 
747 	if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
748 		ubi_msg(ubi, "MTD device %d is write-protected, attach in read-only mode",
749 			ubi->mtd->index);
750 		ubi->ro_mode = 1;
751 	}
752 
753 	/*
754 	 * Note, ideally, we have to initialize @ubi->bad_peb_count here. But
755 	 * unfortunately, MTD does not provide this information. We should loop
756 	 * over all physical eraseblocks and invoke mtd->block_is_bad() for
757 	 * each physical eraseblock. So, we leave @ubi->bad_peb_count
758 	 * uninitialized so far.
759 	 */
760 
761 	return 0;
762 }
763 
764 /**
765  * autoresize - re-size the volume which has the "auto-resize" flag set.
766  * @ubi: UBI device description object
767  * @vol_id: ID of the volume to re-size
768  *
769  * This function re-sizes the volume marked by the %UBI_VTBL_AUTORESIZE_FLG in
770  * the volume table to the largest possible size. See comments in ubi-header.h
771  * for more description of the flag. Returns zero in case of success and a
772  * negative error code in case of failure.
773  */
774 static int autoresize(struct ubi_device *ubi, int vol_id)
775 {
776 	struct ubi_volume_desc desc;
777 	struct ubi_volume *vol = ubi->volumes[vol_id];
778 	int err, old_reserved_pebs = vol->reserved_pebs;
779 
780 	if (ubi->ro_mode) {
781 		ubi_warn(ubi, "skip auto-resize because of R/O mode");
782 		return 0;
783 	}
784 
785 	/*
786 	 * Clear the auto-resize flag in the volume in-memory copy of the
787 	 * volume table, and 'ubi_resize_volume()' will propagate this change
788 	 * to the flash.
789 	 */
790 	ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;
791 
792 	if (ubi->avail_pebs == 0) {
793 		struct ubi_vtbl_record vtbl_rec;
794 
795 		/*
796 		 * No available PEBs to re-size the volume, clear the flag on
797 		 * flash and exit.
798 		 */
799 		vtbl_rec = ubi->vtbl[vol_id];
800 		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
801 		if (err)
802 			ubi_err(ubi, "cannot clean auto-resize flag for volume %d",
803 				vol_id);
804 	} else {
805 		desc.vol = vol;
806 		err = ubi_resize_volume(&desc,
807 					old_reserved_pebs + ubi->avail_pebs);
808 		if (err)
809 			ubi_err(ubi, "cannot auto-resize volume %d",
810 				vol_id);
811 	}
812 
813 	if (err)
814 		return err;
815 
816 	ubi_msg(ubi, "volume %d (\"%s\") re-sized from %d to %d LEBs",
817 		vol_id, vol->name, old_reserved_pebs, vol->reserved_pebs);
818 	return 0;
819 }
820 
821 /**
822  * ubi_attach_mtd_dev - attach an MTD device.
823  * @mtd: MTD device description object
824  * @ubi_num: number to assign to the new UBI device
825  * @vid_hdr_offset: VID header offset
826  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
827  * @disable_fm: whether disable fastmap
828  *
829  * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
830  * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
831  * which case this function finds a vacant device number and assigns it
832  * automatically. Returns the new UBI device number in case of success and a
833  * negative error code in case of failure.
834  *
835  * If @disable_fm is true, ubi doesn't create new fastmap even the module param
836  * 'fm_autoconvert' is set, and existed old fastmap will be destroyed after
837  * doing full scanning.
838  *
839  * Note, the invocations of this function has to be serialized by the
840  * @ubi_devices_mutex.
841  */
842 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
843 		       int vid_hdr_offset, int max_beb_per1024, bool disable_fm)
844 {
845 	struct ubi_device *ubi;
846 	int i, err;
847 
848 	if (max_beb_per1024 < 0 || max_beb_per1024 > MAX_MTD_UBI_BEB_LIMIT)
849 		return -EINVAL;
850 
851 	if (!max_beb_per1024)
852 		max_beb_per1024 = CONFIG_MTD_UBI_BEB_LIMIT;
853 
854 	/*
855 	 * Check if we already have the same MTD device attached.
856 	 *
857 	 * Note, this function assumes that UBI devices creations and deletions
858 	 * are serialized, so it does not take the &ubi_devices_lock.
859 	 */
860 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
861 		ubi = ubi_devices[i];
862 		if (ubi && mtd->index == ubi->mtd->index) {
863 			pr_err("ubi: mtd%d is already attached to ubi%d\n",
864 				mtd->index, i);
865 			return -EEXIST;
866 		}
867 	}
868 
869 	/*
870 	 * Make sure this MTD device is not emulated on top of an UBI volume
871 	 * already. Well, generally this recursion works fine, but there are
872 	 * different problems like the UBI module takes a reference to itself
873 	 * by attaching (and thus, opening) the emulated MTD device. This
874 	 * results in inability to unload the module. And in general it makes
875 	 * no sense to attach emulated MTD devices, so we prohibit this.
876 	 */
877 	if (mtd->type == MTD_UBIVOLUME) {
878 		pr_err("ubi: refuse attaching mtd%d - it is already emulated on top of UBI\n",
879 			mtd->index);
880 		return -EINVAL;
881 	}
882 
883 	/*
884 	 * Both UBI and UBIFS have been designed for SLC NAND and NOR flashes.
885 	 * MLC NAND is different and needs special care, otherwise UBI or UBIFS
886 	 * will die soon and you will lose all your data.
887 	 * Relax this rule if the partition we're attaching to operates in SLC
888 	 * mode.
889 	 */
890 	if (mtd->type == MTD_MLCNANDFLASH &&
891 	    !(mtd->flags & MTD_SLC_ON_MLC_EMULATION)) {
892 		pr_err("ubi: refuse attaching mtd%d - MLC NAND is not supported\n",
893 			mtd->index);
894 		return -EINVAL;
895 	}
896 
897 	/* UBI cannot work on flashes with zero erasesize. */
898 	if (!mtd->erasesize) {
899 		pr_err("ubi: refuse attaching mtd%d - zero erasesize flash is not supported\n",
900 			mtd->index);
901 		return -EINVAL;
902 	}
903 
904 	if (ubi_num == UBI_DEV_NUM_AUTO) {
905 		/* Search for an empty slot in the @ubi_devices array */
906 		for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
907 			if (!ubi_devices[ubi_num])
908 				break;
909 		if (ubi_num == UBI_MAX_DEVICES) {
910 			pr_err("ubi: only %d UBI devices may be created\n",
911 				UBI_MAX_DEVICES);
912 			return -ENFILE;
913 		}
914 	} else {
915 		if (ubi_num >= UBI_MAX_DEVICES)
916 			return -EINVAL;
917 
918 		/* Make sure ubi_num is not busy */
919 		if (ubi_devices[ubi_num]) {
920 			pr_err("ubi: ubi%i already exists\n", ubi_num);
921 			return -EEXIST;
922 		}
923 	}
924 
925 	ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
926 	if (!ubi)
927 		return -ENOMEM;
928 
929 	device_initialize(&ubi->dev);
930 	ubi->dev.release = dev_release;
931 	ubi->dev.class = &ubi_class;
932 	ubi->dev.groups = ubi_dev_groups;
933 	ubi->dev.parent = &mtd->dev;
934 
935 	ubi->mtd = mtd;
936 	ubi->ubi_num = ubi_num;
937 	ubi->vid_hdr_offset = vid_hdr_offset;
938 	ubi->autoresize_vol_id = -1;
939 
940 #ifdef CONFIG_MTD_UBI_FASTMAP
941 	ubi->fm_pool.used = ubi->fm_pool.size = 0;
942 	ubi->fm_wl_pool.used = ubi->fm_wl_pool.size = 0;
943 
944 	/*
945 	 * fm_pool.max_size is 5% of the total number of PEBs but it's also
946 	 * between UBI_FM_MAX_POOL_SIZE and UBI_FM_MIN_POOL_SIZE.
947 	 */
948 	ubi->fm_pool.max_size = min(((int)mtd_div_by_eb(ubi->mtd->size,
949 		ubi->mtd) / 100) * 5, UBI_FM_MAX_POOL_SIZE);
950 	ubi->fm_pool.max_size = max(ubi->fm_pool.max_size,
951 		UBI_FM_MIN_POOL_SIZE);
952 
953 	ubi->fm_wl_pool.max_size = ubi->fm_pool.max_size / 2;
954 	ubi->fm_disabled = (!fm_autoconvert || disable_fm) ? 1 : 0;
955 	if (fm_debug)
956 		ubi_enable_dbg_chk_fastmap(ubi);
957 
958 	if (!ubi->fm_disabled && (int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd)
959 	    <= UBI_FM_MAX_START) {
960 		ubi_err(ubi, "More than %i PEBs are needed for fastmap, sorry.",
961 			UBI_FM_MAX_START);
962 		ubi->fm_disabled = 1;
963 	}
964 
965 	ubi_msg(ubi, "default fastmap pool size: %d", ubi->fm_pool.max_size);
966 	ubi_msg(ubi, "default fastmap WL pool size: %d",
967 		ubi->fm_wl_pool.max_size);
968 #else
969 	ubi->fm_disabled = 1;
970 #endif
971 	mutex_init(&ubi->buf_mutex);
972 	mutex_init(&ubi->ckvol_mutex);
973 	mutex_init(&ubi->device_mutex);
974 	spin_lock_init(&ubi->volumes_lock);
975 	init_rwsem(&ubi->fm_protect);
976 	init_rwsem(&ubi->fm_eba_sem);
977 
978 	ubi_msg(ubi, "attaching mtd%d", mtd->index);
979 
980 	err = io_init(ubi, max_beb_per1024);
981 	if (err)
982 		goto out_free;
983 
984 	err = -ENOMEM;
985 	ubi->peb_buf = vmalloc(ubi->peb_size);
986 	if (!ubi->peb_buf)
987 		goto out_free;
988 
989 #ifdef CONFIG_MTD_UBI_FASTMAP
990 	ubi->fm_size = ubi_calc_fm_size(ubi);
991 	ubi->fm_buf = vzalloc(ubi->fm_size);
992 	if (!ubi->fm_buf)
993 		goto out_free;
994 #endif
995 	err = ubi_attach(ubi, disable_fm ? 1 : 0);
996 	if (err) {
997 		ubi_err(ubi, "failed to attach mtd%d, error %d",
998 			mtd->index, err);
999 		goto out_free;
1000 	}
1001 
1002 	if (ubi->autoresize_vol_id != -1) {
1003 		err = autoresize(ubi, ubi->autoresize_vol_id);
1004 		if (err)
1005 			goto out_detach;
1006 	}
1007 
1008 	err = uif_init(ubi);
1009 	if (err)
1010 		goto out_detach;
1011 
1012 	err = ubi_debugfs_init_dev(ubi);
1013 	if (err)
1014 		goto out_uif;
1015 
1016 	ubi->bgt_thread = kthread_create(ubi_thread, ubi, "%s", ubi->bgt_name);
1017 	if (IS_ERR(ubi->bgt_thread)) {
1018 		err = PTR_ERR(ubi->bgt_thread);
1019 		ubi_err(ubi, "cannot spawn \"%s\", error %d",
1020 			ubi->bgt_name, err);
1021 		goto out_debugfs;
1022 	}
1023 
1024 	ubi_msg(ubi, "attached mtd%d (name \"%s\", size %llu MiB)",
1025 		mtd->index, mtd->name, ubi->flash_size >> 20);
1026 	ubi_msg(ubi, "PEB size: %d bytes (%d KiB), LEB size: %d bytes",
1027 		ubi->peb_size, ubi->peb_size >> 10, ubi->leb_size);
1028 	ubi_msg(ubi, "min./max. I/O unit sizes: %d/%d, sub-page size %d",
1029 		ubi->min_io_size, ubi->max_write_size, ubi->hdrs_min_io_size);
1030 	ubi_msg(ubi, "VID header offset: %d (aligned %d), data offset: %d",
1031 		ubi->vid_hdr_offset, ubi->vid_hdr_aloffset, ubi->leb_start);
1032 	ubi_msg(ubi, "good PEBs: %d, bad PEBs: %d, corrupted PEBs: %d",
1033 		ubi->good_peb_count, ubi->bad_peb_count, ubi->corr_peb_count);
1034 	ubi_msg(ubi, "user volume: %d, internal volumes: %d, max. volumes count: %d",
1035 		ubi->vol_count - UBI_INT_VOL_COUNT, UBI_INT_VOL_COUNT,
1036 		ubi->vtbl_slots);
1037 	ubi_msg(ubi, "max/mean erase counter: %d/%d, WL threshold: %d, image sequence number: %u",
1038 		ubi->max_ec, ubi->mean_ec, CONFIG_MTD_UBI_WL_THRESHOLD,
1039 		ubi->image_seq);
1040 	ubi_msg(ubi, "available PEBs: %d, total reserved PEBs: %d, PEBs reserved for bad PEB handling: %d",
1041 		ubi->avail_pebs, ubi->rsvd_pebs, ubi->beb_rsvd_pebs);
1042 
1043 	/*
1044 	 * The below lock makes sure we do not race with 'ubi_thread()' which
1045 	 * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
1046 	 */
1047 	spin_lock(&ubi->wl_lock);
1048 	ubi->thread_enabled = 1;
1049 	wake_up_process(ubi->bgt_thread);
1050 	spin_unlock(&ubi->wl_lock);
1051 
1052 	ubi_devices[ubi_num] = ubi;
1053 	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
1054 	return ubi_num;
1055 
1056 out_debugfs:
1057 	ubi_debugfs_exit_dev(ubi);
1058 out_uif:
1059 	uif_close(ubi);
1060 out_detach:
1061 	ubi_wl_close(ubi);
1062 	ubi_free_all_volumes(ubi);
1063 	vfree(ubi->vtbl);
1064 out_free:
1065 	vfree(ubi->peb_buf);
1066 	vfree(ubi->fm_buf);
1067 	put_device(&ubi->dev);
1068 	return err;
1069 }
1070 
1071 /**
1072  * ubi_detach_mtd_dev - detach an MTD device.
1073  * @ubi_num: UBI device number to detach from
1074  * @anyway: detach MTD even if device reference count is not zero
1075  *
1076  * This function destroys an UBI device number @ubi_num and detaches the
1077  * underlying MTD device. Returns zero in case of success and %-EBUSY if the
1078  * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
1079  * exist.
1080  *
1081  * Note, the invocations of this function has to be serialized by the
1082  * @ubi_devices_mutex.
1083  */
1084 int ubi_detach_mtd_dev(int ubi_num, int anyway)
1085 {
1086 	struct ubi_device *ubi;
1087 
1088 	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
1089 		return -EINVAL;
1090 
1091 	ubi = ubi_get_device(ubi_num);
1092 	if (!ubi)
1093 		return -EINVAL;
1094 
1095 	spin_lock(&ubi_devices_lock);
1096 	put_device(&ubi->dev);
1097 	ubi->ref_count -= 1;
1098 	if (ubi->ref_count) {
1099 		if (!anyway) {
1100 			spin_unlock(&ubi_devices_lock);
1101 			return -EBUSY;
1102 		}
1103 		/* This may only happen if there is a bug */
1104 		ubi_err(ubi, "%s reference count %d, destroy anyway",
1105 			ubi->ubi_name, ubi->ref_count);
1106 	}
1107 	ubi_devices[ubi_num] = NULL;
1108 	spin_unlock(&ubi_devices_lock);
1109 
1110 	ubi_assert(ubi_num == ubi->ubi_num);
1111 	ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
1112 	ubi_msg(ubi, "detaching mtd%d", ubi->mtd->index);
1113 #ifdef CONFIG_MTD_UBI_FASTMAP
1114 	/* If we don't write a new fastmap at detach time we lose all
1115 	 * EC updates that have been made since the last written fastmap.
1116 	 * In case of fastmap debugging we omit the update to simulate an
1117 	 * unclean shutdown. */
1118 	if (!ubi_dbg_chk_fastmap(ubi))
1119 		ubi_update_fastmap(ubi);
1120 #endif
1121 	/*
1122 	 * Before freeing anything, we have to stop the background thread to
1123 	 * prevent it from doing anything on this device while we are freeing.
1124 	 */
1125 	if (ubi->bgt_thread)
1126 		kthread_stop(ubi->bgt_thread);
1127 
1128 #ifdef CONFIG_MTD_UBI_FASTMAP
1129 	cancel_work_sync(&ubi->fm_work);
1130 #endif
1131 	ubi_debugfs_exit_dev(ubi);
1132 	uif_close(ubi);
1133 
1134 	ubi_wl_close(ubi);
1135 	ubi_free_internal_volumes(ubi);
1136 	vfree(ubi->vtbl);
1137 	vfree(ubi->peb_buf);
1138 	vfree(ubi->fm_buf);
1139 	ubi_msg(ubi, "mtd%d is detached", ubi->mtd->index);
1140 	put_mtd_device(ubi->mtd);
1141 	put_device(&ubi->dev);
1142 	return 0;
1143 }
1144 
1145 /**
1146  * open_mtd_by_chdev - open an MTD device by its character device node path.
1147  * @mtd_dev: MTD character device node path
1148  *
1149  * This helper function opens an MTD device by its character node device path.
1150  * Returns MTD device description object in case of success and a negative
1151  * error code in case of failure.
1152  */
1153 static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
1154 {
1155 	int err, minor;
1156 	struct path path;
1157 	struct kstat stat;
1158 
1159 	/* Probably this is an MTD character device node path */
1160 	err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
1161 	if (err)
1162 		return ERR_PTR(err);
1163 
1164 	err = vfs_getattr(&path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
1165 	path_put(&path);
1166 	if (err)
1167 		return ERR_PTR(err);
1168 
1169 	/* MTD device number is defined by the major / minor numbers */
1170 	if (MAJOR(stat.rdev) != MTD_CHAR_MAJOR || !S_ISCHR(stat.mode))
1171 		return ERR_PTR(-EINVAL);
1172 
1173 	minor = MINOR(stat.rdev);
1174 
1175 	if (minor & 1)
1176 		/*
1177 		 * Just do not think the "/dev/mtdrX" devices support is need,
1178 		 * so do not support them to avoid doing extra work.
1179 		 */
1180 		return ERR_PTR(-EINVAL);
1181 
1182 	return get_mtd_device(NULL, minor / 2);
1183 }
1184 
1185 /**
1186  * open_mtd_device - open MTD device by name, character device path, or number.
1187  * @mtd_dev: name, character device node path, or MTD device device number
1188  *
1189  * This function tries to open and MTD device described by @mtd_dev string,
1190  * which is first treated as ASCII MTD device number, and if it is not true, it
1191  * is treated as MTD device name, and if that is also not true, it is treated
1192  * as MTD character device node path. Returns MTD device description object in
1193  * case of success and a negative error code in case of failure.
1194  */
1195 static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
1196 {
1197 	struct mtd_info *mtd;
1198 	int mtd_num;
1199 	char *endp;
1200 
1201 	mtd_num = simple_strtoul(mtd_dev, &endp, 0);
1202 	if (*endp != '\0' || mtd_dev == endp) {
1203 		/*
1204 		 * This does not look like an ASCII integer, probably this is
1205 		 * MTD device name.
1206 		 */
1207 		mtd = get_mtd_device_nm(mtd_dev);
1208 		if (PTR_ERR(mtd) == -ENODEV)
1209 			/* Probably this is an MTD character device node path */
1210 			mtd = open_mtd_by_chdev(mtd_dev);
1211 	} else
1212 		mtd = get_mtd_device(NULL, mtd_num);
1213 
1214 	return mtd;
1215 }
1216 
1217 static int __init ubi_init(void)
1218 {
1219 	int err, i, k;
1220 
1221 	/* Ensure that EC and VID headers have correct size */
1222 	BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
1223 	BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);
1224 
1225 	if (mtd_devs > UBI_MAX_DEVICES) {
1226 		pr_err("UBI error: too many MTD devices, maximum is %d\n",
1227 		       UBI_MAX_DEVICES);
1228 		return -EINVAL;
1229 	}
1230 
1231 	/* Create base sysfs directory and sysfs files */
1232 	err = class_register(&ubi_class);
1233 	if (err < 0)
1234 		return err;
1235 
1236 	err = misc_register(&ubi_ctrl_cdev);
1237 	if (err) {
1238 		pr_err("UBI error: cannot register device\n");
1239 		goto out;
1240 	}
1241 
1242 	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
1243 					      sizeof(struct ubi_wl_entry),
1244 					      0, 0, NULL);
1245 	if (!ubi_wl_entry_slab) {
1246 		err = -ENOMEM;
1247 		goto out_dev_unreg;
1248 	}
1249 
1250 	err = ubi_debugfs_init();
1251 	if (err)
1252 		goto out_slab;
1253 
1254 
1255 	/* Attach MTD devices */
1256 	for (i = 0; i < mtd_devs; i++) {
1257 		struct mtd_dev_param *p = &mtd_dev_param[i];
1258 		struct mtd_info *mtd;
1259 
1260 		cond_resched();
1261 
1262 		mtd = open_mtd_device(p->name);
1263 		if (IS_ERR(mtd)) {
1264 			err = PTR_ERR(mtd);
1265 			pr_err("UBI error: cannot open mtd %s, error %d\n",
1266 			       p->name, err);
1267 			/* See comment below re-ubi_is_module(). */
1268 			if (ubi_is_module())
1269 				goto out_detach;
1270 			continue;
1271 		}
1272 
1273 		mutex_lock(&ubi_devices_mutex);
1274 		err = ubi_attach_mtd_dev(mtd, p->ubi_num,
1275 					 p->vid_hdr_offs, p->max_beb_per1024,
1276 					 p->enable_fm == 0);
1277 		mutex_unlock(&ubi_devices_mutex);
1278 		if (err < 0) {
1279 			pr_err("UBI error: cannot attach mtd%d\n",
1280 			       mtd->index);
1281 			put_mtd_device(mtd);
1282 
1283 			/*
1284 			 * Originally UBI stopped initializing on any error.
1285 			 * However, later on it was found out that this
1286 			 * behavior is not very good when UBI is compiled into
1287 			 * the kernel and the MTD devices to attach are passed
1288 			 * through the command line. Indeed, UBI failure
1289 			 * stopped whole boot sequence.
1290 			 *
1291 			 * To fix this, we changed the behavior for the
1292 			 * non-module case, but preserved the old behavior for
1293 			 * the module case, just for compatibility. This is a
1294 			 * little inconsistent, though.
1295 			 */
1296 			if (ubi_is_module())
1297 				goto out_detach;
1298 		}
1299 	}
1300 
1301 	err = ubiblock_init();
1302 	if (err) {
1303 		pr_err("UBI error: block: cannot initialize, error %d\n", err);
1304 
1305 		/* See comment above re-ubi_is_module(). */
1306 		if (ubi_is_module())
1307 			goto out_detach;
1308 	}
1309 
1310 	return 0;
1311 
1312 out_detach:
1313 	for (k = 0; k < i; k++)
1314 		if (ubi_devices[k]) {
1315 			mutex_lock(&ubi_devices_mutex);
1316 			ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
1317 			mutex_unlock(&ubi_devices_mutex);
1318 		}
1319 	ubi_debugfs_exit();
1320 out_slab:
1321 	kmem_cache_destroy(ubi_wl_entry_slab);
1322 out_dev_unreg:
1323 	misc_deregister(&ubi_ctrl_cdev);
1324 out:
1325 	class_unregister(&ubi_class);
1326 	pr_err("UBI error: cannot initialize UBI, error %d\n", err);
1327 	return err;
1328 }
1329 late_initcall(ubi_init);
1330 
1331 static void __exit ubi_exit(void)
1332 {
1333 	int i;
1334 
1335 	ubiblock_exit();
1336 
1337 	for (i = 0; i < UBI_MAX_DEVICES; i++)
1338 		if (ubi_devices[i]) {
1339 			mutex_lock(&ubi_devices_mutex);
1340 			ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
1341 			mutex_unlock(&ubi_devices_mutex);
1342 		}
1343 	ubi_debugfs_exit();
1344 	kmem_cache_destroy(ubi_wl_entry_slab);
1345 	misc_deregister(&ubi_ctrl_cdev);
1346 	class_unregister(&ubi_class);
1347 }
1348 module_exit(ubi_exit);
1349 
1350 /**
1351  * bytes_str_to_int - convert a number of bytes string into an integer.
1352  * @str: the string to convert
1353  *
1354  * This function returns positive resulting integer in case of success and a
1355  * negative error code in case of failure.
1356  */
1357 static int bytes_str_to_int(const char *str)
1358 {
1359 	char *endp;
1360 	unsigned long result;
1361 
1362 	result = simple_strtoul(str, &endp, 0);
1363 	if (str == endp || result >= INT_MAX) {
1364 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1365 		return -EINVAL;
1366 	}
1367 
1368 	switch (*endp) {
1369 	case 'G':
1370 		result *= 1024;
1371 		fallthrough;
1372 	case 'M':
1373 		result *= 1024;
1374 		fallthrough;
1375 	case 'K':
1376 		result *= 1024;
1377 		break;
1378 	case '\0':
1379 		break;
1380 	default:
1381 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1382 		return -EINVAL;
1383 	}
1384 
1385 	return result;
1386 }
1387 
1388 /**
1389  * ubi_mtd_param_parse - parse the 'mtd=' UBI parameter.
1390  * @val: the parameter value to parse
1391  * @kp: not used
1392  *
1393  * This function returns zero in case of success and a negative error code in
1394  * case of error.
1395  */
1396 static int ubi_mtd_param_parse(const char *val, const struct kernel_param *kp)
1397 {
1398 	int i, len;
1399 	struct mtd_dev_param *p;
1400 	char buf[MTD_PARAM_LEN_MAX];
1401 	char *pbuf = &buf[0];
1402 	char *tokens[MTD_PARAM_MAX_COUNT], *token;
1403 
1404 	if (!val)
1405 		return -EINVAL;
1406 
1407 	if (mtd_devs == UBI_MAX_DEVICES) {
1408 		pr_err("UBI error: too many parameters, max. is %d\n",
1409 		       UBI_MAX_DEVICES);
1410 		return -EINVAL;
1411 	}
1412 
1413 	len = strnlen(val, MTD_PARAM_LEN_MAX);
1414 	if (len == MTD_PARAM_LEN_MAX) {
1415 		pr_err("UBI error: parameter \"%s\" is too long, max. is %d\n",
1416 		       val, MTD_PARAM_LEN_MAX);
1417 		return -EINVAL;
1418 	}
1419 
1420 	if (len == 0) {
1421 		pr_warn("UBI warning: empty 'mtd=' parameter - ignored\n");
1422 		return 0;
1423 	}
1424 
1425 	strcpy(buf, val);
1426 
1427 	/* Get rid of the final newline */
1428 	if (buf[len - 1] == '\n')
1429 		buf[len - 1] = '\0';
1430 
1431 	for (i = 0; i < MTD_PARAM_MAX_COUNT; i++)
1432 		tokens[i] = strsep(&pbuf, ",");
1433 
1434 	if (pbuf) {
1435 		pr_err("UBI error: too many arguments at \"%s\"\n", val);
1436 		return -EINVAL;
1437 	}
1438 
1439 	p = &mtd_dev_param[mtd_devs];
1440 	strcpy(&p->name[0], tokens[0]);
1441 
1442 	token = tokens[1];
1443 	if (token) {
1444 		p->vid_hdr_offs = bytes_str_to_int(token);
1445 
1446 		if (p->vid_hdr_offs < 0)
1447 			return p->vid_hdr_offs;
1448 	}
1449 
1450 	token = tokens[2];
1451 	if (token) {
1452 		int err = kstrtoint(token, 10, &p->max_beb_per1024);
1453 
1454 		if (err) {
1455 			pr_err("UBI error: bad value for max_beb_per1024 parameter: %s\n",
1456 			       token);
1457 			return -EINVAL;
1458 		}
1459 	}
1460 
1461 	token = tokens[3];
1462 	if (token) {
1463 		int err = kstrtoint(token, 10, &p->ubi_num);
1464 
1465 		if (err) {
1466 			pr_err("UBI error: bad value for ubi_num parameter: %s\n",
1467 			       token);
1468 			return -EINVAL;
1469 		}
1470 	} else
1471 		p->ubi_num = UBI_DEV_NUM_AUTO;
1472 
1473 	token = tokens[4];
1474 	if (token) {
1475 		int err = kstrtoint(token, 10, &p->enable_fm);
1476 
1477 		if (err) {
1478 			pr_err("UBI error: bad value for enable_fm parameter: %s\n",
1479 				token);
1480 			return -EINVAL;
1481 		}
1482 	} else
1483 		p->enable_fm = 0;
1484 
1485 	mtd_devs += 1;
1486 	return 0;
1487 }
1488 
1489 module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 0400);
1490 MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024[,ubi_num]]].\n"
1491 		      "Multiple \"mtd\" parameters may be specified.\n"
1492 		      "MTD devices may be specified by their number, name, or path to the MTD character device node.\n"
1493 		      "Optional \"vid_hdr_offs\" parameter specifies UBI VID header position to be used by UBI. (default value if 0)\n"
1494 		      "Optional \"max_beb_per1024\" parameter specifies the maximum expected bad eraseblock per 1024 eraseblocks. (default value ("
1495 		      __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0)\n"
1496 		      "Optional \"ubi_num\" parameter specifies UBI device number which have to be assigned to the newly created UBI device (assigned automatically by default)\n"
1497 		      "Optional \"enable_fm\" parameter determines whether to enable fastmap during attach. If the value is non-zero, fastmap is enabled. Default value is 0.\n"
1498 		      "\n"
1499 		      "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
1500 		      "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"
1501 		      "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"
1502 		      "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"
1503 		      "example 5: mtd=1,0,0,5 mtd=2,0,0,6,1 - attach MTD device /dev/mtd1 to UBI 5 and disable fastmap; attach MTD device /dev/mtd2 to UBI 6 and enable fastmap.(only works when fastmap is enabled and fm_autoconvert=Y).\n"
1504 		      "\t(e.g. if the NAND *chipset* has 4096 PEB, 100 will be reserved for this UBI device).");
1505 #ifdef CONFIG_MTD_UBI_FASTMAP
1506 module_param(fm_autoconvert, bool, 0644);
1507 MODULE_PARM_DESC(fm_autoconvert, "Set this parameter to enable fastmap automatically on images without a fastmap.");
1508 module_param(fm_debug, bool, 0);
1509 MODULE_PARM_DESC(fm_debug, "Set this parameter to enable fastmap debugging by default. Warning, this will make fastmap slow!");
1510 #endif
1511 MODULE_VERSION(__stringify(UBI_VERSION));
1512 MODULE_DESCRIPTION("UBI - Unsorted Block Images");
1513 MODULE_AUTHOR("Artem Bityutskiy");
1514 MODULE_LICENSE("GPL");
1515