xref: /linux/drivers/mtd/ubi/build.c (revision b7019ac550eb3916f34d79db583e9b7ea2524afa)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) International Business Machines Corp., 2006
4  * Copyright (c) Nokia Corporation, 2007
5  *
6  * Author: Artem Bityutskiy (Битюцкий Артём),
7  *         Frank Haverkamp
8  */
9 
10 /*
11  * This file includes UBI initialization and building of UBI devices.
12  *
13  * When UBI is initialized, it attaches all the MTD devices specified as the
14  * module load parameters or the kernel boot parameters. If MTD devices were
15  * specified, UBI does not attach any MTD device, but it is possible to do
16  * later using the "UBI control device".
17  */
18 
19 #include <linux/err.h>
20 #include <linux/module.h>
21 #include <linux/moduleparam.h>
22 #include <linux/stringify.h>
23 #include <linux/namei.h>
24 #include <linux/stat.h>
25 #include <linux/miscdevice.h>
26 #include <linux/mtd/partitions.h>
27 #include <linux/log2.h>
28 #include <linux/kthread.h>
29 #include <linux/kernel.h>
30 #include <linux/slab.h>
31 #include <linux/major.h>
32 #include "ubi.h"
33 
34 /* Maximum length of the 'mtd=' parameter */
35 #define MTD_PARAM_LEN_MAX 64
36 
37 /* Maximum number of comma-separated items in the 'mtd=' parameter */
38 #define MTD_PARAM_MAX_COUNT 4
39 
40 /* Maximum value for the number of bad PEBs per 1024 PEBs */
41 #define MAX_MTD_UBI_BEB_LIMIT 768
42 
43 #ifdef CONFIG_MTD_UBI_MODULE
44 #define ubi_is_module() 1
45 #else
46 #define ubi_is_module() 0
47 #endif
48 
49 /**
50  * struct mtd_dev_param - MTD device parameter description data structure.
51  * @name: MTD character device node path, MTD device name, or MTD device number
52  *        string
53  * @vid_hdr_offs: VID header offset
54  * @max_beb_per1024: maximum expected number of bad PEBs per 1024 PEBs
55  */
56 struct mtd_dev_param {
57 	char name[MTD_PARAM_LEN_MAX];
58 	int ubi_num;
59 	int vid_hdr_offs;
60 	int max_beb_per1024;
61 };
62 
63 /* Numbers of elements set in the @mtd_dev_param array */
64 static int mtd_devs;
65 
66 /* MTD devices specification parameters */
67 static struct mtd_dev_param mtd_dev_param[UBI_MAX_DEVICES];
68 #ifdef CONFIG_MTD_UBI_FASTMAP
69 /* UBI module parameter to enable fastmap automatically on non-fastmap images */
70 static bool fm_autoconvert;
71 static bool fm_debug;
72 #endif
73 
74 /* Slab cache for wear-leveling entries */
75 struct kmem_cache *ubi_wl_entry_slab;
76 
77 /* UBI control character device */
78 static struct miscdevice ubi_ctrl_cdev = {
79 	.minor = MISC_DYNAMIC_MINOR,
80 	.name = "ubi_ctrl",
81 	.fops = &ubi_ctrl_cdev_operations,
82 };
83 
84 /* All UBI devices in system */
85 static struct ubi_device *ubi_devices[UBI_MAX_DEVICES];
86 
87 /* Serializes UBI devices creations and removals */
88 DEFINE_MUTEX(ubi_devices_mutex);
89 
90 /* Protects @ubi_devices and @ubi->ref_count */
91 static DEFINE_SPINLOCK(ubi_devices_lock);
92 
93 /* "Show" method for files in '/<sysfs>/class/ubi/' */
94 /* UBI version attribute ('/<sysfs>/class/ubi/version') */
95 static ssize_t version_show(struct class *class, struct class_attribute *attr,
96 			    char *buf)
97 {
98 	return sprintf(buf, "%d\n", UBI_VERSION);
99 }
100 static CLASS_ATTR_RO(version);
101 
102 static struct attribute *ubi_class_attrs[] = {
103 	&class_attr_version.attr,
104 	NULL,
105 };
106 ATTRIBUTE_GROUPS(ubi_class);
107 
108 /* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
109 struct class ubi_class = {
110 	.name		= UBI_NAME_STR,
111 	.owner		= THIS_MODULE,
112 	.class_groups	= ubi_class_groups,
113 };
114 
115 static ssize_t dev_attribute_show(struct device *dev,
116 				  struct device_attribute *attr, char *buf);
117 
118 /* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
119 static struct device_attribute dev_eraseblock_size =
120 	__ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
121 static struct device_attribute dev_avail_eraseblocks =
122 	__ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
123 static struct device_attribute dev_total_eraseblocks =
124 	__ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
125 static struct device_attribute dev_volumes_count =
126 	__ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
127 static struct device_attribute dev_max_ec =
128 	__ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
129 static struct device_attribute dev_reserved_for_bad =
130 	__ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
131 static struct device_attribute dev_bad_peb_count =
132 	__ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
133 static struct device_attribute dev_max_vol_count =
134 	__ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
135 static struct device_attribute dev_min_io_size =
136 	__ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
137 static struct device_attribute dev_bgt_enabled =
138 	__ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);
139 static struct device_attribute dev_mtd_num =
140 	__ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
141 static struct device_attribute dev_ro_mode =
142 	__ATTR(ro_mode, S_IRUGO, dev_attribute_show, NULL);
143 
144 /**
145  * ubi_volume_notify - send a volume change notification.
146  * @ubi: UBI device description object
147  * @vol: volume description object of the changed volume
148  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
149  *
150  * This is a helper function which notifies all subscribers about a volume
151  * change event (creation, removal, re-sizing, re-naming, updating). Returns
152  * zero in case of success and a negative error code in case of failure.
153  */
154 int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
155 {
156 	int ret;
157 	struct ubi_notification nt;
158 
159 	ubi_do_get_device_info(ubi, &nt.di);
160 	ubi_do_get_volume_info(ubi, vol, &nt.vi);
161 
162 	switch (ntype) {
163 	case UBI_VOLUME_ADDED:
164 	case UBI_VOLUME_REMOVED:
165 	case UBI_VOLUME_RESIZED:
166 	case UBI_VOLUME_RENAMED:
167 		ret = ubi_update_fastmap(ubi);
168 		if (ret)
169 			ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
170 	}
171 
172 	return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
173 }
174 
175 /**
176  * ubi_notify_all - send a notification to all volumes.
177  * @ubi: UBI device description object
178  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
179  * @nb: the notifier to call
180  *
181  * This function walks all volumes of UBI device @ubi and sends the @ntype
182  * notification for each volume. If @nb is %NULL, then all registered notifiers
183  * are called, otherwise only the @nb notifier is called. Returns the number of
184  * sent notifications.
185  */
186 int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
187 {
188 	struct ubi_notification nt;
189 	int i, count = 0;
190 
191 	ubi_do_get_device_info(ubi, &nt.di);
192 
193 	mutex_lock(&ubi->device_mutex);
194 	for (i = 0; i < ubi->vtbl_slots; i++) {
195 		/*
196 		 * Since the @ubi->device is locked, and we are not going to
197 		 * change @ubi->volumes, we do not have to lock
198 		 * @ubi->volumes_lock.
199 		 */
200 		if (!ubi->volumes[i])
201 			continue;
202 
203 		ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
204 		if (nb)
205 			nb->notifier_call(nb, ntype, &nt);
206 		else
207 			blocking_notifier_call_chain(&ubi_notifiers, ntype,
208 						     &nt);
209 		count += 1;
210 	}
211 	mutex_unlock(&ubi->device_mutex);
212 
213 	return count;
214 }
215 
216 /**
217  * ubi_enumerate_volumes - send "add" notification for all existing volumes.
218  * @nb: the notifier to call
219  *
220  * This function walks all UBI devices and volumes and sends the
221  * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
222  * registered notifiers are called, otherwise only the @nb notifier is called.
223  * Returns the number of sent notifications.
224  */
225 int ubi_enumerate_volumes(struct notifier_block *nb)
226 {
227 	int i, count = 0;
228 
229 	/*
230 	 * Since the @ubi_devices_mutex is locked, and we are not going to
231 	 * change @ubi_devices, we do not have to lock @ubi_devices_lock.
232 	 */
233 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
234 		struct ubi_device *ubi = ubi_devices[i];
235 
236 		if (!ubi)
237 			continue;
238 		count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
239 	}
240 
241 	return count;
242 }
243 
244 /**
245  * ubi_get_device - get UBI device.
246  * @ubi_num: UBI device number
247  *
248  * This function returns UBI device description object for UBI device number
249  * @ubi_num, or %NULL if the device does not exist. This function increases the
250  * device reference count to prevent removal of the device. In other words, the
251  * device cannot be removed if its reference count is not zero.
252  */
253 struct ubi_device *ubi_get_device(int ubi_num)
254 {
255 	struct ubi_device *ubi;
256 
257 	spin_lock(&ubi_devices_lock);
258 	ubi = ubi_devices[ubi_num];
259 	if (ubi) {
260 		ubi_assert(ubi->ref_count >= 0);
261 		ubi->ref_count += 1;
262 		get_device(&ubi->dev);
263 	}
264 	spin_unlock(&ubi_devices_lock);
265 
266 	return ubi;
267 }
268 
269 /**
270  * ubi_put_device - drop an UBI device reference.
271  * @ubi: UBI device description object
272  */
273 void ubi_put_device(struct ubi_device *ubi)
274 {
275 	spin_lock(&ubi_devices_lock);
276 	ubi->ref_count -= 1;
277 	put_device(&ubi->dev);
278 	spin_unlock(&ubi_devices_lock);
279 }
280 
281 /**
282  * ubi_get_by_major - get UBI device by character device major number.
283  * @major: major number
284  *
285  * This function is similar to 'ubi_get_device()', but it searches the device
286  * by its major number.
287  */
288 struct ubi_device *ubi_get_by_major(int major)
289 {
290 	int i;
291 	struct ubi_device *ubi;
292 
293 	spin_lock(&ubi_devices_lock);
294 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
295 		ubi = ubi_devices[i];
296 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
297 			ubi_assert(ubi->ref_count >= 0);
298 			ubi->ref_count += 1;
299 			get_device(&ubi->dev);
300 			spin_unlock(&ubi_devices_lock);
301 			return ubi;
302 		}
303 	}
304 	spin_unlock(&ubi_devices_lock);
305 
306 	return NULL;
307 }
308 
309 /**
310  * ubi_major2num - get UBI device number by character device major number.
311  * @major: major number
312  *
313  * This function searches UBI device number object by its major number. If UBI
314  * device was not found, this function returns -ENODEV, otherwise the UBI device
315  * number is returned.
316  */
317 int ubi_major2num(int major)
318 {
319 	int i, ubi_num = -ENODEV;
320 
321 	spin_lock(&ubi_devices_lock);
322 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
323 		struct ubi_device *ubi = ubi_devices[i];
324 
325 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
326 			ubi_num = ubi->ubi_num;
327 			break;
328 		}
329 	}
330 	spin_unlock(&ubi_devices_lock);
331 
332 	return ubi_num;
333 }
334 
335 /* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
336 static ssize_t dev_attribute_show(struct device *dev,
337 				  struct device_attribute *attr, char *buf)
338 {
339 	ssize_t ret;
340 	struct ubi_device *ubi;
341 
342 	/*
343 	 * The below code looks weird, but it actually makes sense. We get the
344 	 * UBI device reference from the contained 'struct ubi_device'. But it
345 	 * is unclear if the device was removed or not yet. Indeed, if the
346 	 * device was removed before we increased its reference count,
347 	 * 'ubi_get_device()' will return -ENODEV and we fail.
348 	 *
349 	 * Remember, 'struct ubi_device' is freed in the release function, so
350 	 * we still can use 'ubi->ubi_num'.
351 	 */
352 	ubi = container_of(dev, struct ubi_device, dev);
353 	ubi = ubi_get_device(ubi->ubi_num);
354 	if (!ubi)
355 		return -ENODEV;
356 
357 	if (attr == &dev_eraseblock_size)
358 		ret = sprintf(buf, "%d\n", ubi->leb_size);
359 	else if (attr == &dev_avail_eraseblocks)
360 		ret = sprintf(buf, "%d\n", ubi->avail_pebs);
361 	else if (attr == &dev_total_eraseblocks)
362 		ret = sprintf(buf, "%d\n", ubi->good_peb_count);
363 	else if (attr == &dev_volumes_count)
364 		ret = sprintf(buf, "%d\n", ubi->vol_count - UBI_INT_VOL_COUNT);
365 	else if (attr == &dev_max_ec)
366 		ret = sprintf(buf, "%d\n", ubi->max_ec);
367 	else if (attr == &dev_reserved_for_bad)
368 		ret = sprintf(buf, "%d\n", ubi->beb_rsvd_pebs);
369 	else if (attr == &dev_bad_peb_count)
370 		ret = sprintf(buf, "%d\n", ubi->bad_peb_count);
371 	else if (attr == &dev_max_vol_count)
372 		ret = sprintf(buf, "%d\n", ubi->vtbl_slots);
373 	else if (attr == &dev_min_io_size)
374 		ret = sprintf(buf, "%d\n", ubi->min_io_size);
375 	else if (attr == &dev_bgt_enabled)
376 		ret = sprintf(buf, "%d\n", ubi->thread_enabled);
377 	else if (attr == &dev_mtd_num)
378 		ret = sprintf(buf, "%d\n", ubi->mtd->index);
379 	else if (attr == &dev_ro_mode)
380 		ret = sprintf(buf, "%d\n", ubi->ro_mode);
381 	else
382 		ret = -EINVAL;
383 
384 	ubi_put_device(ubi);
385 	return ret;
386 }
387 
388 static struct attribute *ubi_dev_attrs[] = {
389 	&dev_eraseblock_size.attr,
390 	&dev_avail_eraseblocks.attr,
391 	&dev_total_eraseblocks.attr,
392 	&dev_volumes_count.attr,
393 	&dev_max_ec.attr,
394 	&dev_reserved_for_bad.attr,
395 	&dev_bad_peb_count.attr,
396 	&dev_max_vol_count.attr,
397 	&dev_min_io_size.attr,
398 	&dev_bgt_enabled.attr,
399 	&dev_mtd_num.attr,
400 	&dev_ro_mode.attr,
401 	NULL
402 };
403 ATTRIBUTE_GROUPS(ubi_dev);
404 
405 static void dev_release(struct device *dev)
406 {
407 	struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);
408 
409 	kfree(ubi);
410 }
411 
412 /**
413  * kill_volumes - destroy all user volumes.
414  * @ubi: UBI device description object
415  */
416 static void kill_volumes(struct ubi_device *ubi)
417 {
418 	int i;
419 
420 	for (i = 0; i < ubi->vtbl_slots; i++)
421 		if (ubi->volumes[i])
422 			ubi_free_volume(ubi, ubi->volumes[i]);
423 }
424 
425 /**
426  * uif_init - initialize user interfaces for an UBI device.
427  * @ubi: UBI device description object
428  *
429  * This function initializes various user interfaces for an UBI device. If the
430  * initialization fails at an early stage, this function frees all the
431  * resources it allocated, returns an error.
432  *
433  * This function returns zero in case of success and a negative error code in
434  * case of failure.
435  */
436 static int uif_init(struct ubi_device *ubi)
437 {
438 	int i, err;
439 	dev_t dev;
440 
441 	sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);
442 
443 	/*
444 	 * Major numbers for the UBI character devices are allocated
445 	 * dynamically. Major numbers of volume character devices are
446 	 * equivalent to ones of the corresponding UBI character device. Minor
447 	 * numbers of UBI character devices are 0, while minor numbers of
448 	 * volume character devices start from 1. Thus, we allocate one major
449 	 * number and ubi->vtbl_slots + 1 minor numbers.
450 	 */
451 	err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
452 	if (err) {
453 		ubi_err(ubi, "cannot register UBI character devices");
454 		return err;
455 	}
456 
457 	ubi->dev.devt = dev;
458 
459 	ubi_assert(MINOR(dev) == 0);
460 	cdev_init(&ubi->cdev, &ubi_cdev_operations);
461 	dbg_gen("%s major is %u", ubi->ubi_name, MAJOR(dev));
462 	ubi->cdev.owner = THIS_MODULE;
463 
464 	dev_set_name(&ubi->dev, UBI_NAME_STR "%d", ubi->ubi_num);
465 	err = cdev_device_add(&ubi->cdev, &ubi->dev);
466 	if (err)
467 		goto out_unreg;
468 
469 	for (i = 0; i < ubi->vtbl_slots; i++)
470 		if (ubi->volumes[i]) {
471 			err = ubi_add_volume(ubi, ubi->volumes[i]);
472 			if (err) {
473 				ubi_err(ubi, "cannot add volume %d", i);
474 				goto out_volumes;
475 			}
476 		}
477 
478 	return 0;
479 
480 out_volumes:
481 	kill_volumes(ubi);
482 	cdev_device_del(&ubi->cdev, &ubi->dev);
483 out_unreg:
484 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
485 	ubi_err(ubi, "cannot initialize UBI %s, error %d",
486 		ubi->ubi_name, err);
487 	return err;
488 }
489 
490 /**
491  * uif_close - close user interfaces for an UBI device.
492  * @ubi: UBI device description object
493  *
494  * Note, since this function un-registers UBI volume device objects (@vol->dev),
495  * the memory allocated voe the volumes is freed as well (in the release
496  * function).
497  */
498 static void uif_close(struct ubi_device *ubi)
499 {
500 	kill_volumes(ubi);
501 	cdev_device_del(&ubi->cdev, &ubi->dev);
502 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
503 }
504 
505 /**
506  * ubi_free_internal_volumes - free internal volumes.
507  * @ubi: UBI device description object
508  */
509 void ubi_free_internal_volumes(struct ubi_device *ubi)
510 {
511 	int i;
512 
513 	for (i = ubi->vtbl_slots;
514 	     i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
515 		ubi_eba_replace_table(ubi->volumes[i], NULL);
516 		ubi_fastmap_destroy_checkmap(ubi->volumes[i]);
517 		kfree(ubi->volumes[i]);
518 	}
519 }
520 
521 static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
522 {
523 	int limit, device_pebs;
524 	uint64_t device_size;
525 
526 	if (!max_beb_per1024) {
527 		/*
528 		 * Since max_beb_per1024 has not been set by the user in either
529 		 * the cmdline or Kconfig, use mtd_max_bad_blocks to set the
530 		 * limit if it is supported by the device.
531 		 */
532 		limit = mtd_max_bad_blocks(ubi->mtd, 0, ubi->mtd->size);
533 		if (limit < 0)
534 			return 0;
535 		return limit;
536 	}
537 
538 	/*
539 	 * Here we are using size of the entire flash chip and
540 	 * not just the MTD partition size because the maximum
541 	 * number of bad eraseblocks is a percentage of the
542 	 * whole device and bad eraseblocks are not fairly
543 	 * distributed over the flash chip. So the worst case
544 	 * is that all the bad eraseblocks of the chip are in
545 	 * the MTD partition we are attaching (ubi->mtd).
546 	 */
547 	device_size = mtd_get_device_size(ubi->mtd);
548 	device_pebs = mtd_div_by_eb(device_size, ubi->mtd);
549 	limit = mult_frac(device_pebs, max_beb_per1024, 1024);
550 
551 	/* Round it up */
552 	if (mult_frac(limit, 1024, max_beb_per1024) < device_pebs)
553 		limit += 1;
554 
555 	return limit;
556 }
557 
558 /**
559  * io_init - initialize I/O sub-system for a given UBI device.
560  * @ubi: UBI device description object
561  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
562  *
563  * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
564  * assumed:
565  *   o EC header is always at offset zero - this cannot be changed;
566  *   o VID header starts just after the EC header at the closest address
567  *     aligned to @io->hdrs_min_io_size;
568  *   o data starts just after the VID header at the closest address aligned to
569  *     @io->min_io_size
570  *
571  * This function returns zero in case of success and a negative error code in
572  * case of failure.
573  */
574 static int io_init(struct ubi_device *ubi, int max_beb_per1024)
575 {
576 	dbg_gen("sizeof(struct ubi_ainf_peb) %zu", sizeof(struct ubi_ainf_peb));
577 	dbg_gen("sizeof(struct ubi_wl_entry) %zu", sizeof(struct ubi_wl_entry));
578 
579 	if (ubi->mtd->numeraseregions != 0) {
580 		/*
581 		 * Some flashes have several erase regions. Different regions
582 		 * may have different eraseblock size and other
583 		 * characteristics. It looks like mostly multi-region flashes
584 		 * have one "main" region and one or more small regions to
585 		 * store boot loader code or boot parameters or whatever. I
586 		 * guess we should just pick the largest region. But this is
587 		 * not implemented.
588 		 */
589 		ubi_err(ubi, "multiple regions, not implemented");
590 		return -EINVAL;
591 	}
592 
593 	if (ubi->vid_hdr_offset < 0)
594 		return -EINVAL;
595 
596 	/*
597 	 * Note, in this implementation we support MTD devices with 0x7FFFFFFF
598 	 * physical eraseblocks maximum.
599 	 */
600 
601 	ubi->peb_size   = ubi->mtd->erasesize;
602 	ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
603 	ubi->flash_size = ubi->mtd->size;
604 
605 	if (mtd_can_have_bb(ubi->mtd)) {
606 		ubi->bad_allowed = 1;
607 		ubi->bad_peb_limit = get_bad_peb_limit(ubi, max_beb_per1024);
608 	}
609 
610 	if (ubi->mtd->type == MTD_NORFLASH) {
611 		ubi_assert(ubi->mtd->writesize == 1);
612 		ubi->nor_flash = 1;
613 	}
614 
615 	ubi->min_io_size = ubi->mtd->writesize;
616 	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
617 
618 	/*
619 	 * Make sure minimal I/O unit is power of 2. Note, there is no
620 	 * fundamental reason for this assumption. It is just an optimization
621 	 * which allows us to avoid costly division operations.
622 	 */
623 	if (!is_power_of_2(ubi->min_io_size)) {
624 		ubi_err(ubi, "min. I/O unit (%d) is not power of 2",
625 			ubi->min_io_size);
626 		return -EINVAL;
627 	}
628 
629 	ubi_assert(ubi->hdrs_min_io_size > 0);
630 	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
631 	ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
632 
633 	ubi->max_write_size = ubi->mtd->writebufsize;
634 	/*
635 	 * Maximum write size has to be greater or equivalent to min. I/O
636 	 * size, and be multiple of min. I/O size.
637 	 */
638 	if (ubi->max_write_size < ubi->min_io_size ||
639 	    ubi->max_write_size % ubi->min_io_size ||
640 	    !is_power_of_2(ubi->max_write_size)) {
641 		ubi_err(ubi, "bad write buffer size %d for %d min. I/O unit",
642 			ubi->max_write_size, ubi->min_io_size);
643 		return -EINVAL;
644 	}
645 
646 	/* Calculate default aligned sizes of EC and VID headers */
647 	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
648 	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
649 
650 	dbg_gen("min_io_size      %d", ubi->min_io_size);
651 	dbg_gen("max_write_size   %d", ubi->max_write_size);
652 	dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
653 	dbg_gen("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
654 	dbg_gen("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
655 
656 	if (ubi->vid_hdr_offset == 0)
657 		/* Default offset */
658 		ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
659 				      ubi->ec_hdr_alsize;
660 	else {
661 		ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
662 						~(ubi->hdrs_min_io_size - 1);
663 		ubi->vid_hdr_shift = ubi->vid_hdr_offset -
664 						ubi->vid_hdr_aloffset;
665 	}
666 
667 	/* Similar for the data offset */
668 	ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
669 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
670 
671 	dbg_gen("vid_hdr_offset   %d", ubi->vid_hdr_offset);
672 	dbg_gen("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
673 	dbg_gen("vid_hdr_shift    %d", ubi->vid_hdr_shift);
674 	dbg_gen("leb_start        %d", ubi->leb_start);
675 
676 	/* The shift must be aligned to 32-bit boundary */
677 	if (ubi->vid_hdr_shift % 4) {
678 		ubi_err(ubi, "unaligned VID header shift %d",
679 			ubi->vid_hdr_shift);
680 		return -EINVAL;
681 	}
682 
683 	/* Check sanity */
684 	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
685 	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
686 	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
687 	    ubi->leb_start & (ubi->min_io_size - 1)) {
688 		ubi_err(ubi, "bad VID header (%d) or data offsets (%d)",
689 			ubi->vid_hdr_offset, ubi->leb_start);
690 		return -EINVAL;
691 	}
692 
693 	/*
694 	 * Set maximum amount of physical erroneous eraseblocks to be 10%.
695 	 * Erroneous PEB are those which have read errors.
696 	 */
697 	ubi->max_erroneous = ubi->peb_count / 10;
698 	if (ubi->max_erroneous < 16)
699 		ubi->max_erroneous = 16;
700 	dbg_gen("max_erroneous    %d", ubi->max_erroneous);
701 
702 	/*
703 	 * It may happen that EC and VID headers are situated in one minimal
704 	 * I/O unit. In this case we can only accept this UBI image in
705 	 * read-only mode.
706 	 */
707 	if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
708 		ubi_warn(ubi, "EC and VID headers are in the same minimal I/O unit, switch to read-only mode");
709 		ubi->ro_mode = 1;
710 	}
711 
712 	ubi->leb_size = ubi->peb_size - ubi->leb_start;
713 
714 	if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
715 		ubi_msg(ubi, "MTD device %d is write-protected, attach in read-only mode",
716 			ubi->mtd->index);
717 		ubi->ro_mode = 1;
718 	}
719 
720 	/*
721 	 * Note, ideally, we have to initialize @ubi->bad_peb_count here. But
722 	 * unfortunately, MTD does not provide this information. We should loop
723 	 * over all physical eraseblocks and invoke mtd->block_is_bad() for
724 	 * each physical eraseblock. So, we leave @ubi->bad_peb_count
725 	 * uninitialized so far.
726 	 */
727 
728 	return 0;
729 }
730 
731 /**
732  * autoresize - re-size the volume which has the "auto-resize" flag set.
733  * @ubi: UBI device description object
734  * @vol_id: ID of the volume to re-size
735  *
736  * This function re-sizes the volume marked by the %UBI_VTBL_AUTORESIZE_FLG in
737  * the volume table to the largest possible size. See comments in ubi-header.h
738  * for more description of the flag. Returns zero in case of success and a
739  * negative error code in case of failure.
740  */
741 static int autoresize(struct ubi_device *ubi, int vol_id)
742 {
743 	struct ubi_volume_desc desc;
744 	struct ubi_volume *vol = ubi->volumes[vol_id];
745 	int err, old_reserved_pebs = vol->reserved_pebs;
746 
747 	if (ubi->ro_mode) {
748 		ubi_warn(ubi, "skip auto-resize because of R/O mode");
749 		return 0;
750 	}
751 
752 	/*
753 	 * Clear the auto-resize flag in the volume in-memory copy of the
754 	 * volume table, and 'ubi_resize_volume()' will propagate this change
755 	 * to the flash.
756 	 */
757 	ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;
758 
759 	if (ubi->avail_pebs == 0) {
760 		struct ubi_vtbl_record vtbl_rec;
761 
762 		/*
763 		 * No available PEBs to re-size the volume, clear the flag on
764 		 * flash and exit.
765 		 */
766 		vtbl_rec = ubi->vtbl[vol_id];
767 		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
768 		if (err)
769 			ubi_err(ubi, "cannot clean auto-resize flag for volume %d",
770 				vol_id);
771 	} else {
772 		desc.vol = vol;
773 		err = ubi_resize_volume(&desc,
774 					old_reserved_pebs + ubi->avail_pebs);
775 		if (err)
776 			ubi_err(ubi, "cannot auto-resize volume %d",
777 				vol_id);
778 	}
779 
780 	if (err)
781 		return err;
782 
783 	ubi_msg(ubi, "volume %d (\"%s\") re-sized from %d to %d LEBs",
784 		vol_id, vol->name, old_reserved_pebs, vol->reserved_pebs);
785 	return 0;
786 }
787 
788 /**
789  * ubi_attach_mtd_dev - attach an MTD device.
790  * @mtd: MTD device description object
791  * @ubi_num: number to assign to the new UBI device
792  * @vid_hdr_offset: VID header offset
793  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
794  *
795  * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
796  * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
797  * which case this function finds a vacant device number and assigns it
798  * automatically. Returns the new UBI device number in case of success and a
799  * negative error code in case of failure.
800  *
801  * Note, the invocations of this function has to be serialized by the
802  * @ubi_devices_mutex.
803  */
804 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
805 		       int vid_hdr_offset, int max_beb_per1024)
806 {
807 	struct ubi_device *ubi;
808 	int i, err;
809 
810 	if (max_beb_per1024 < 0 || max_beb_per1024 > MAX_MTD_UBI_BEB_LIMIT)
811 		return -EINVAL;
812 
813 	if (!max_beb_per1024)
814 		max_beb_per1024 = CONFIG_MTD_UBI_BEB_LIMIT;
815 
816 	/*
817 	 * Check if we already have the same MTD device attached.
818 	 *
819 	 * Note, this function assumes that UBI devices creations and deletions
820 	 * are serialized, so it does not take the &ubi_devices_lock.
821 	 */
822 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
823 		ubi = ubi_devices[i];
824 		if (ubi && mtd->index == ubi->mtd->index) {
825 			pr_err("ubi: mtd%d is already attached to ubi%d\n",
826 				mtd->index, i);
827 			return -EEXIST;
828 		}
829 	}
830 
831 	/*
832 	 * Make sure this MTD device is not emulated on top of an UBI volume
833 	 * already. Well, generally this recursion works fine, but there are
834 	 * different problems like the UBI module takes a reference to itself
835 	 * by attaching (and thus, opening) the emulated MTD device. This
836 	 * results in inability to unload the module. And in general it makes
837 	 * no sense to attach emulated MTD devices, so we prohibit this.
838 	 */
839 	if (mtd->type == MTD_UBIVOLUME) {
840 		pr_err("ubi: refuse attaching mtd%d - it is already emulated on top of UBI\n",
841 			mtd->index);
842 		return -EINVAL;
843 	}
844 
845 	/*
846 	 * Both UBI and UBIFS have been designed for SLC NAND and NOR flashes.
847 	 * MLC NAND is different and needs special care, otherwise UBI or UBIFS
848 	 * will die soon and you will lose all your data.
849 	 */
850 	if (mtd->type == MTD_MLCNANDFLASH) {
851 		pr_err("ubi: refuse attaching mtd%d - MLC NAND is not supported\n",
852 			mtd->index);
853 		return -EINVAL;
854 	}
855 
856 	if (ubi_num == UBI_DEV_NUM_AUTO) {
857 		/* Search for an empty slot in the @ubi_devices array */
858 		for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
859 			if (!ubi_devices[ubi_num])
860 				break;
861 		if (ubi_num == UBI_MAX_DEVICES) {
862 			pr_err("ubi: only %d UBI devices may be created\n",
863 				UBI_MAX_DEVICES);
864 			return -ENFILE;
865 		}
866 	} else {
867 		if (ubi_num >= UBI_MAX_DEVICES)
868 			return -EINVAL;
869 
870 		/* Make sure ubi_num is not busy */
871 		if (ubi_devices[ubi_num]) {
872 			pr_err("ubi: ubi%i already exists\n", ubi_num);
873 			return -EEXIST;
874 		}
875 	}
876 
877 	ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
878 	if (!ubi)
879 		return -ENOMEM;
880 
881 	device_initialize(&ubi->dev);
882 	ubi->dev.release = dev_release;
883 	ubi->dev.class = &ubi_class;
884 	ubi->dev.groups = ubi_dev_groups;
885 
886 	ubi->mtd = mtd;
887 	ubi->ubi_num = ubi_num;
888 	ubi->vid_hdr_offset = vid_hdr_offset;
889 	ubi->autoresize_vol_id = -1;
890 
891 #ifdef CONFIG_MTD_UBI_FASTMAP
892 	ubi->fm_pool.used = ubi->fm_pool.size = 0;
893 	ubi->fm_wl_pool.used = ubi->fm_wl_pool.size = 0;
894 
895 	/*
896 	 * fm_pool.max_size is 5% of the total number of PEBs but it's also
897 	 * between UBI_FM_MAX_POOL_SIZE and UBI_FM_MIN_POOL_SIZE.
898 	 */
899 	ubi->fm_pool.max_size = min(((int)mtd_div_by_eb(ubi->mtd->size,
900 		ubi->mtd) / 100) * 5, UBI_FM_MAX_POOL_SIZE);
901 	ubi->fm_pool.max_size = max(ubi->fm_pool.max_size,
902 		UBI_FM_MIN_POOL_SIZE);
903 
904 	ubi->fm_wl_pool.max_size = ubi->fm_pool.max_size / 2;
905 	ubi->fm_disabled = !fm_autoconvert;
906 	if (fm_debug)
907 		ubi_enable_dbg_chk_fastmap(ubi);
908 
909 	if (!ubi->fm_disabled && (int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd)
910 	    <= UBI_FM_MAX_START) {
911 		ubi_err(ubi, "More than %i PEBs are needed for fastmap, sorry.",
912 			UBI_FM_MAX_START);
913 		ubi->fm_disabled = 1;
914 	}
915 
916 	ubi_msg(ubi, "default fastmap pool size: %d", ubi->fm_pool.max_size);
917 	ubi_msg(ubi, "default fastmap WL pool size: %d",
918 		ubi->fm_wl_pool.max_size);
919 #else
920 	ubi->fm_disabled = 1;
921 #endif
922 	mutex_init(&ubi->buf_mutex);
923 	mutex_init(&ubi->ckvol_mutex);
924 	mutex_init(&ubi->device_mutex);
925 	spin_lock_init(&ubi->volumes_lock);
926 	init_rwsem(&ubi->fm_protect);
927 	init_rwsem(&ubi->fm_eba_sem);
928 
929 	ubi_msg(ubi, "attaching mtd%d", mtd->index);
930 
931 	err = io_init(ubi, max_beb_per1024);
932 	if (err)
933 		goto out_free;
934 
935 	err = -ENOMEM;
936 	ubi->peb_buf = vmalloc(ubi->peb_size);
937 	if (!ubi->peb_buf)
938 		goto out_free;
939 
940 #ifdef CONFIG_MTD_UBI_FASTMAP
941 	ubi->fm_size = ubi_calc_fm_size(ubi);
942 	ubi->fm_buf = vzalloc(ubi->fm_size);
943 	if (!ubi->fm_buf)
944 		goto out_free;
945 #endif
946 	err = ubi_attach(ubi, 0);
947 	if (err) {
948 		ubi_err(ubi, "failed to attach mtd%d, error %d",
949 			mtd->index, err);
950 		goto out_free;
951 	}
952 
953 	if (ubi->autoresize_vol_id != -1) {
954 		err = autoresize(ubi, ubi->autoresize_vol_id);
955 		if (err)
956 			goto out_detach;
957 	}
958 
959 	/* Make device "available" before it becomes accessible via sysfs */
960 	ubi_devices[ubi_num] = ubi;
961 
962 	err = uif_init(ubi);
963 	if (err)
964 		goto out_detach;
965 
966 	err = ubi_debugfs_init_dev(ubi);
967 	if (err)
968 		goto out_uif;
969 
970 	ubi->bgt_thread = kthread_create(ubi_thread, ubi, "%s", ubi->bgt_name);
971 	if (IS_ERR(ubi->bgt_thread)) {
972 		err = PTR_ERR(ubi->bgt_thread);
973 		ubi_err(ubi, "cannot spawn \"%s\", error %d",
974 			ubi->bgt_name, err);
975 		goto out_debugfs;
976 	}
977 
978 	ubi_msg(ubi, "attached mtd%d (name \"%s\", size %llu MiB)",
979 		mtd->index, mtd->name, ubi->flash_size >> 20);
980 	ubi_msg(ubi, "PEB size: %d bytes (%d KiB), LEB size: %d bytes",
981 		ubi->peb_size, ubi->peb_size >> 10, ubi->leb_size);
982 	ubi_msg(ubi, "min./max. I/O unit sizes: %d/%d, sub-page size %d",
983 		ubi->min_io_size, ubi->max_write_size, ubi->hdrs_min_io_size);
984 	ubi_msg(ubi, "VID header offset: %d (aligned %d), data offset: %d",
985 		ubi->vid_hdr_offset, ubi->vid_hdr_aloffset, ubi->leb_start);
986 	ubi_msg(ubi, "good PEBs: %d, bad PEBs: %d, corrupted PEBs: %d",
987 		ubi->good_peb_count, ubi->bad_peb_count, ubi->corr_peb_count);
988 	ubi_msg(ubi, "user volume: %d, internal volumes: %d, max. volumes count: %d",
989 		ubi->vol_count - UBI_INT_VOL_COUNT, UBI_INT_VOL_COUNT,
990 		ubi->vtbl_slots);
991 	ubi_msg(ubi, "max/mean erase counter: %d/%d, WL threshold: %d, image sequence number: %u",
992 		ubi->max_ec, ubi->mean_ec, CONFIG_MTD_UBI_WL_THRESHOLD,
993 		ubi->image_seq);
994 	ubi_msg(ubi, "available PEBs: %d, total reserved PEBs: %d, PEBs reserved for bad PEB handling: %d",
995 		ubi->avail_pebs, ubi->rsvd_pebs, ubi->beb_rsvd_pebs);
996 
997 	/*
998 	 * The below lock makes sure we do not race with 'ubi_thread()' which
999 	 * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
1000 	 */
1001 	spin_lock(&ubi->wl_lock);
1002 	ubi->thread_enabled = 1;
1003 	wake_up_process(ubi->bgt_thread);
1004 	spin_unlock(&ubi->wl_lock);
1005 
1006 	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
1007 	return ubi_num;
1008 
1009 out_debugfs:
1010 	ubi_debugfs_exit_dev(ubi);
1011 out_uif:
1012 	uif_close(ubi);
1013 out_detach:
1014 	ubi_devices[ubi_num] = NULL;
1015 	ubi_wl_close(ubi);
1016 	ubi_free_internal_volumes(ubi);
1017 	vfree(ubi->vtbl);
1018 out_free:
1019 	vfree(ubi->peb_buf);
1020 	vfree(ubi->fm_buf);
1021 	put_device(&ubi->dev);
1022 	return err;
1023 }
1024 
1025 /**
1026  * ubi_detach_mtd_dev - detach an MTD device.
1027  * @ubi_num: UBI device number to detach from
1028  * @anyway: detach MTD even if device reference count is not zero
1029  *
1030  * This function destroys an UBI device number @ubi_num and detaches the
1031  * underlying MTD device. Returns zero in case of success and %-EBUSY if the
1032  * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
1033  * exist.
1034  *
1035  * Note, the invocations of this function has to be serialized by the
1036  * @ubi_devices_mutex.
1037  */
1038 int ubi_detach_mtd_dev(int ubi_num, int anyway)
1039 {
1040 	struct ubi_device *ubi;
1041 
1042 	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
1043 		return -EINVAL;
1044 
1045 	ubi = ubi_get_device(ubi_num);
1046 	if (!ubi)
1047 		return -EINVAL;
1048 
1049 	spin_lock(&ubi_devices_lock);
1050 	put_device(&ubi->dev);
1051 	ubi->ref_count -= 1;
1052 	if (ubi->ref_count) {
1053 		if (!anyway) {
1054 			spin_unlock(&ubi_devices_lock);
1055 			return -EBUSY;
1056 		}
1057 		/* This may only happen if there is a bug */
1058 		ubi_err(ubi, "%s reference count %d, destroy anyway",
1059 			ubi->ubi_name, ubi->ref_count);
1060 	}
1061 	ubi_devices[ubi_num] = NULL;
1062 	spin_unlock(&ubi_devices_lock);
1063 
1064 	ubi_assert(ubi_num == ubi->ubi_num);
1065 	ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
1066 	ubi_msg(ubi, "detaching mtd%d", ubi->mtd->index);
1067 #ifdef CONFIG_MTD_UBI_FASTMAP
1068 	/* If we don't write a new fastmap at detach time we lose all
1069 	 * EC updates that have been made since the last written fastmap.
1070 	 * In case of fastmap debugging we omit the update to simulate an
1071 	 * unclean shutdown. */
1072 	if (!ubi_dbg_chk_fastmap(ubi))
1073 		ubi_update_fastmap(ubi);
1074 #endif
1075 	/*
1076 	 * Before freeing anything, we have to stop the background thread to
1077 	 * prevent it from doing anything on this device while we are freeing.
1078 	 */
1079 	if (ubi->bgt_thread)
1080 		kthread_stop(ubi->bgt_thread);
1081 
1082 #ifdef CONFIG_MTD_UBI_FASTMAP
1083 	cancel_work_sync(&ubi->fm_work);
1084 #endif
1085 	ubi_debugfs_exit_dev(ubi);
1086 	uif_close(ubi);
1087 
1088 	ubi_wl_close(ubi);
1089 	ubi_free_internal_volumes(ubi);
1090 	vfree(ubi->vtbl);
1091 	vfree(ubi->peb_buf);
1092 	vfree(ubi->fm_buf);
1093 	ubi_msg(ubi, "mtd%d is detached", ubi->mtd->index);
1094 	put_mtd_device(ubi->mtd);
1095 	put_device(&ubi->dev);
1096 	return 0;
1097 }
1098 
1099 /**
1100  * open_mtd_by_chdev - open an MTD device by its character device node path.
1101  * @mtd_dev: MTD character device node path
1102  *
1103  * This helper function opens an MTD device by its character node device path.
1104  * Returns MTD device description object in case of success and a negative
1105  * error code in case of failure.
1106  */
1107 static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
1108 {
1109 	int err, minor;
1110 	struct path path;
1111 	struct kstat stat;
1112 
1113 	/* Probably this is an MTD character device node path */
1114 	err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
1115 	if (err)
1116 		return ERR_PTR(err);
1117 
1118 	err = vfs_getattr(&path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
1119 	path_put(&path);
1120 	if (err)
1121 		return ERR_PTR(err);
1122 
1123 	/* MTD device number is defined by the major / minor numbers */
1124 	if (MAJOR(stat.rdev) != MTD_CHAR_MAJOR || !S_ISCHR(stat.mode))
1125 		return ERR_PTR(-EINVAL);
1126 
1127 	minor = MINOR(stat.rdev);
1128 
1129 	if (minor & 1)
1130 		/*
1131 		 * Just do not think the "/dev/mtdrX" devices support is need,
1132 		 * so do not support them to avoid doing extra work.
1133 		 */
1134 		return ERR_PTR(-EINVAL);
1135 
1136 	return get_mtd_device(NULL, minor / 2);
1137 }
1138 
1139 /**
1140  * open_mtd_device - open MTD device by name, character device path, or number.
1141  * @mtd_dev: name, character device node path, or MTD device device number
1142  *
1143  * This function tries to open and MTD device described by @mtd_dev string,
1144  * which is first treated as ASCII MTD device number, and if it is not true, it
1145  * is treated as MTD device name, and if that is also not true, it is treated
1146  * as MTD character device node path. Returns MTD device description object in
1147  * case of success and a negative error code in case of failure.
1148  */
1149 static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
1150 {
1151 	struct mtd_info *mtd;
1152 	int mtd_num;
1153 	char *endp;
1154 
1155 	mtd_num = simple_strtoul(mtd_dev, &endp, 0);
1156 	if (*endp != '\0' || mtd_dev == endp) {
1157 		/*
1158 		 * This does not look like an ASCII integer, probably this is
1159 		 * MTD device name.
1160 		 */
1161 		mtd = get_mtd_device_nm(mtd_dev);
1162 		if (IS_ERR(mtd) && PTR_ERR(mtd) == -ENODEV)
1163 			/* Probably this is an MTD character device node path */
1164 			mtd = open_mtd_by_chdev(mtd_dev);
1165 	} else
1166 		mtd = get_mtd_device(NULL, mtd_num);
1167 
1168 	return mtd;
1169 }
1170 
1171 static int __init ubi_init(void)
1172 {
1173 	int err, i, k;
1174 
1175 	/* Ensure that EC and VID headers have correct size */
1176 	BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
1177 	BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);
1178 
1179 	if (mtd_devs > UBI_MAX_DEVICES) {
1180 		pr_err("UBI error: too many MTD devices, maximum is %d\n",
1181 		       UBI_MAX_DEVICES);
1182 		return -EINVAL;
1183 	}
1184 
1185 	/* Create base sysfs directory and sysfs files */
1186 	err = class_register(&ubi_class);
1187 	if (err < 0)
1188 		return err;
1189 
1190 	err = misc_register(&ubi_ctrl_cdev);
1191 	if (err) {
1192 		pr_err("UBI error: cannot register device\n");
1193 		goto out;
1194 	}
1195 
1196 	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
1197 					      sizeof(struct ubi_wl_entry),
1198 					      0, 0, NULL);
1199 	if (!ubi_wl_entry_slab) {
1200 		err = -ENOMEM;
1201 		goto out_dev_unreg;
1202 	}
1203 
1204 	err = ubi_debugfs_init();
1205 	if (err)
1206 		goto out_slab;
1207 
1208 
1209 	/* Attach MTD devices */
1210 	for (i = 0; i < mtd_devs; i++) {
1211 		struct mtd_dev_param *p = &mtd_dev_param[i];
1212 		struct mtd_info *mtd;
1213 
1214 		cond_resched();
1215 
1216 		mtd = open_mtd_device(p->name);
1217 		if (IS_ERR(mtd)) {
1218 			err = PTR_ERR(mtd);
1219 			pr_err("UBI error: cannot open mtd %s, error %d\n",
1220 			       p->name, err);
1221 			/* See comment below re-ubi_is_module(). */
1222 			if (ubi_is_module())
1223 				goto out_detach;
1224 			continue;
1225 		}
1226 
1227 		mutex_lock(&ubi_devices_mutex);
1228 		err = ubi_attach_mtd_dev(mtd, p->ubi_num,
1229 					 p->vid_hdr_offs, p->max_beb_per1024);
1230 		mutex_unlock(&ubi_devices_mutex);
1231 		if (err < 0) {
1232 			pr_err("UBI error: cannot attach mtd%d\n",
1233 			       mtd->index);
1234 			put_mtd_device(mtd);
1235 
1236 			/*
1237 			 * Originally UBI stopped initializing on any error.
1238 			 * However, later on it was found out that this
1239 			 * behavior is not very good when UBI is compiled into
1240 			 * the kernel and the MTD devices to attach are passed
1241 			 * through the command line. Indeed, UBI failure
1242 			 * stopped whole boot sequence.
1243 			 *
1244 			 * To fix this, we changed the behavior for the
1245 			 * non-module case, but preserved the old behavior for
1246 			 * the module case, just for compatibility. This is a
1247 			 * little inconsistent, though.
1248 			 */
1249 			if (ubi_is_module())
1250 				goto out_detach;
1251 		}
1252 	}
1253 
1254 	err = ubiblock_init();
1255 	if (err) {
1256 		pr_err("UBI error: block: cannot initialize, error %d\n", err);
1257 
1258 		/* See comment above re-ubi_is_module(). */
1259 		if (ubi_is_module())
1260 			goto out_detach;
1261 	}
1262 
1263 	return 0;
1264 
1265 out_detach:
1266 	for (k = 0; k < i; k++)
1267 		if (ubi_devices[k]) {
1268 			mutex_lock(&ubi_devices_mutex);
1269 			ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
1270 			mutex_unlock(&ubi_devices_mutex);
1271 		}
1272 	ubi_debugfs_exit();
1273 out_slab:
1274 	kmem_cache_destroy(ubi_wl_entry_slab);
1275 out_dev_unreg:
1276 	misc_deregister(&ubi_ctrl_cdev);
1277 out:
1278 	class_unregister(&ubi_class);
1279 	pr_err("UBI error: cannot initialize UBI, error %d\n", err);
1280 	return err;
1281 }
1282 late_initcall(ubi_init);
1283 
1284 static void __exit ubi_exit(void)
1285 {
1286 	int i;
1287 
1288 	ubiblock_exit();
1289 
1290 	for (i = 0; i < UBI_MAX_DEVICES; i++)
1291 		if (ubi_devices[i]) {
1292 			mutex_lock(&ubi_devices_mutex);
1293 			ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
1294 			mutex_unlock(&ubi_devices_mutex);
1295 		}
1296 	ubi_debugfs_exit();
1297 	kmem_cache_destroy(ubi_wl_entry_slab);
1298 	misc_deregister(&ubi_ctrl_cdev);
1299 	class_unregister(&ubi_class);
1300 }
1301 module_exit(ubi_exit);
1302 
1303 /**
1304  * bytes_str_to_int - convert a number of bytes string into an integer.
1305  * @str: the string to convert
1306  *
1307  * This function returns positive resulting integer in case of success and a
1308  * negative error code in case of failure.
1309  */
1310 static int bytes_str_to_int(const char *str)
1311 {
1312 	char *endp;
1313 	unsigned long result;
1314 
1315 	result = simple_strtoul(str, &endp, 0);
1316 	if (str == endp || result >= INT_MAX) {
1317 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1318 		return -EINVAL;
1319 	}
1320 
1321 	switch (*endp) {
1322 	case 'G':
1323 		result *= 1024;
1324 		/* fall through */
1325 	case 'M':
1326 		result *= 1024;
1327 		/* fall through */
1328 	case 'K':
1329 		result *= 1024;
1330 		if (endp[1] == 'i' && endp[2] == 'B')
1331 			endp += 2;
1332 	case '\0':
1333 		break;
1334 	default:
1335 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1336 		return -EINVAL;
1337 	}
1338 
1339 	return result;
1340 }
1341 
1342 /**
1343  * ubi_mtd_param_parse - parse the 'mtd=' UBI parameter.
1344  * @val: the parameter value to parse
1345  * @kp: not used
1346  *
1347  * This function returns zero in case of success and a negative error code in
1348  * case of error.
1349  */
1350 static int ubi_mtd_param_parse(const char *val, const struct kernel_param *kp)
1351 {
1352 	int i, len;
1353 	struct mtd_dev_param *p;
1354 	char buf[MTD_PARAM_LEN_MAX];
1355 	char *pbuf = &buf[0];
1356 	char *tokens[MTD_PARAM_MAX_COUNT], *token;
1357 
1358 	if (!val)
1359 		return -EINVAL;
1360 
1361 	if (mtd_devs == UBI_MAX_DEVICES) {
1362 		pr_err("UBI error: too many parameters, max. is %d\n",
1363 		       UBI_MAX_DEVICES);
1364 		return -EINVAL;
1365 	}
1366 
1367 	len = strnlen(val, MTD_PARAM_LEN_MAX);
1368 	if (len == MTD_PARAM_LEN_MAX) {
1369 		pr_err("UBI error: parameter \"%s\" is too long, max. is %d\n",
1370 		       val, MTD_PARAM_LEN_MAX);
1371 		return -EINVAL;
1372 	}
1373 
1374 	if (len == 0) {
1375 		pr_warn("UBI warning: empty 'mtd=' parameter - ignored\n");
1376 		return 0;
1377 	}
1378 
1379 	strcpy(buf, val);
1380 
1381 	/* Get rid of the final newline */
1382 	if (buf[len - 1] == '\n')
1383 		buf[len - 1] = '\0';
1384 
1385 	for (i = 0; i < MTD_PARAM_MAX_COUNT; i++)
1386 		tokens[i] = strsep(&pbuf, ",");
1387 
1388 	if (pbuf) {
1389 		pr_err("UBI error: too many arguments at \"%s\"\n", val);
1390 		return -EINVAL;
1391 	}
1392 
1393 	p = &mtd_dev_param[mtd_devs];
1394 	strcpy(&p->name[0], tokens[0]);
1395 
1396 	token = tokens[1];
1397 	if (token) {
1398 		p->vid_hdr_offs = bytes_str_to_int(token);
1399 
1400 		if (p->vid_hdr_offs < 0)
1401 			return p->vid_hdr_offs;
1402 	}
1403 
1404 	token = tokens[2];
1405 	if (token) {
1406 		int err = kstrtoint(token, 10, &p->max_beb_per1024);
1407 
1408 		if (err) {
1409 			pr_err("UBI error: bad value for max_beb_per1024 parameter: %s",
1410 			       token);
1411 			return -EINVAL;
1412 		}
1413 	}
1414 
1415 	token = tokens[3];
1416 	if (token) {
1417 		int err = kstrtoint(token, 10, &p->ubi_num);
1418 
1419 		if (err) {
1420 			pr_err("UBI error: bad value for ubi_num parameter: %s",
1421 			       token);
1422 			return -EINVAL;
1423 		}
1424 	} else
1425 		p->ubi_num = UBI_DEV_NUM_AUTO;
1426 
1427 	mtd_devs += 1;
1428 	return 0;
1429 }
1430 
1431 module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 0400);
1432 MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024[,ubi_num]]].\n"
1433 		      "Multiple \"mtd\" parameters may be specified.\n"
1434 		      "MTD devices may be specified by their number, name, or path to the MTD character device node.\n"
1435 		      "Optional \"vid_hdr_offs\" parameter specifies UBI VID header position to be used by UBI. (default value if 0)\n"
1436 		      "Optional \"max_beb_per1024\" parameter specifies the maximum expected bad eraseblock per 1024 eraseblocks. (default value ("
1437 		      __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0)\n"
1438 		      "Optional \"ubi_num\" parameter specifies UBI device number which have to be assigned to the newly created UBI device (assigned automatically by default)\n"
1439 		      "\n"
1440 		      "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
1441 		      "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"
1442 		      "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"
1443 		      "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"
1444 		      "\t(e.g. if the NAND *chipset* has 4096 PEB, 100 will be reserved for this UBI device).");
1445 #ifdef CONFIG_MTD_UBI_FASTMAP
1446 module_param(fm_autoconvert, bool, 0644);
1447 MODULE_PARM_DESC(fm_autoconvert, "Set this parameter to enable fastmap automatically on images without a fastmap.");
1448 module_param(fm_debug, bool, 0);
1449 MODULE_PARM_DESC(fm_debug, "Set this parameter to enable fastmap debugging by default. Warning, this will make fastmap slow!");
1450 #endif
1451 MODULE_VERSION(__stringify(UBI_VERSION));
1452 MODULE_DESCRIPTION("UBI - Unsorted Block Images");
1453 MODULE_AUTHOR("Artem Bityutskiy");
1454 MODULE_LICENSE("GPL");
1455