xref: /linux/drivers/mtd/ubi/build.c (revision d0fde6aae2bacdc024fff43461ba0f325375fa97)
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 6
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  * @need_resv_pool: reserve pool->max_size pebs when value is none-zero
58  */
59 struct mtd_dev_param {
60 	char name[MTD_PARAM_LEN_MAX];
61 	int ubi_num;
62 	int vid_hdr_offs;
63 	int max_beb_per1024;
64 	int enable_fm;
65 	int need_resv_pool;
66 };
67 
68 /* Numbers of elements set in the @mtd_dev_param array */
69 static int mtd_devs;
70 
71 /* MTD devices specification parameters */
72 static struct mtd_dev_param mtd_dev_param[UBI_MAX_DEVICES];
73 #ifdef CONFIG_MTD_UBI_FASTMAP
74 /* UBI module parameter to enable fastmap automatically on non-fastmap images */
75 static bool fm_autoconvert;
76 static bool fm_debug;
77 #endif
78 
79 /* Slab cache for wear-leveling entries */
80 struct kmem_cache *ubi_wl_entry_slab;
81 
82 /* UBI control character device */
83 static struct miscdevice ubi_ctrl_cdev = {
84 	.minor = MISC_DYNAMIC_MINOR,
85 	.name = "ubi_ctrl",
86 	.fops = &ubi_ctrl_cdev_operations,
87 };
88 
89 /* All UBI devices in system */
90 static struct ubi_device *ubi_devices[UBI_MAX_DEVICES];
91 
92 /* Serializes UBI devices creations and removals */
93 DEFINE_MUTEX(ubi_devices_mutex);
94 
95 /* Protects @ubi_devices and @ubi->ref_count */
96 static DEFINE_SPINLOCK(ubi_devices_lock);
97 
98 /* "Show" method for files in '/<sysfs>/class/ubi/' */
99 /* UBI version attribute ('/<sysfs>/class/ubi/version') */
100 static ssize_t version_show(const struct class *class, const struct class_attribute *attr,
101 			    char *buf)
102 {
103 	return sprintf(buf, "%d\n", UBI_VERSION);
104 }
105 static CLASS_ATTR_RO(version);
106 
107 static struct attribute *ubi_class_attrs[] = {
108 	&class_attr_version.attr,
109 	NULL,
110 };
111 ATTRIBUTE_GROUPS(ubi_class);
112 
113 /* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
114 struct class ubi_class = {
115 	.name		= UBI_NAME_STR,
116 	.class_groups	= ubi_class_groups,
117 };
118 
119 static ssize_t dev_attribute_show(struct device *dev,
120 				  struct device_attribute *attr, char *buf);
121 
122 /* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
123 static struct device_attribute dev_eraseblock_size =
124 	__ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
125 static struct device_attribute dev_avail_eraseblocks =
126 	__ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
127 static struct device_attribute dev_total_eraseblocks =
128 	__ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
129 static struct device_attribute dev_volumes_count =
130 	__ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
131 static struct device_attribute dev_max_ec =
132 	__ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
133 static struct device_attribute dev_reserved_for_bad =
134 	__ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
135 static struct device_attribute dev_bad_peb_count =
136 	__ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
137 static struct device_attribute dev_max_vol_count =
138 	__ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
139 static struct device_attribute dev_min_io_size =
140 	__ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
141 static struct device_attribute dev_bgt_enabled =
142 	__ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);
143 static struct device_attribute dev_mtd_num =
144 	__ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
145 static struct device_attribute dev_ro_mode =
146 	__ATTR(ro_mode, S_IRUGO, dev_attribute_show, NULL);
147 
148 /**
149  * ubi_volume_notify - send a volume change notification.
150  * @ubi: UBI device description object
151  * @vol: volume description object of the changed volume
152  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
153  *
154  * This is a helper function which notifies all subscribers about a volume
155  * change event (creation, removal, re-sizing, re-naming, updating). Returns
156  * zero in case of success and a negative error code in case of failure.
157  */
158 int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
159 {
160 	int ret;
161 	struct ubi_notification nt;
162 
163 	ubi_do_get_device_info(ubi, &nt.di);
164 	ubi_do_get_volume_info(ubi, vol, &nt.vi);
165 
166 	switch (ntype) {
167 	case UBI_VOLUME_ADDED:
168 	case UBI_VOLUME_REMOVED:
169 	case UBI_VOLUME_RESIZED:
170 	case UBI_VOLUME_RENAMED:
171 		ret = ubi_update_fastmap(ubi);
172 		if (ret)
173 			ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
174 	}
175 
176 	return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
177 }
178 
179 /**
180  * ubi_notify_all - send a notification to all volumes.
181  * @ubi: UBI device description object
182  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
183  * @nb: the notifier to call
184  *
185  * This function walks all volumes of UBI device @ubi and sends the @ntype
186  * notification for each volume. If @nb is %NULL, then all registered notifiers
187  * are called, otherwise only the @nb notifier is called. Returns the number of
188  * sent notifications.
189  */
190 int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
191 {
192 	struct ubi_notification nt;
193 	int i, count = 0;
194 
195 	ubi_do_get_device_info(ubi, &nt.di);
196 
197 	mutex_lock(&ubi->device_mutex);
198 	for (i = 0; i < ubi->vtbl_slots; i++) {
199 		/*
200 		 * Since the @ubi->device is locked, and we are not going to
201 		 * change @ubi->volumes, we do not have to lock
202 		 * @ubi->volumes_lock.
203 		 */
204 		if (!ubi->volumes[i])
205 			continue;
206 
207 		ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
208 		if (nb)
209 			nb->notifier_call(nb, ntype, &nt);
210 		else
211 			blocking_notifier_call_chain(&ubi_notifiers, ntype,
212 						     &nt);
213 		count += 1;
214 	}
215 	mutex_unlock(&ubi->device_mutex);
216 
217 	return count;
218 }
219 
220 /**
221  * ubi_enumerate_volumes - send "add" notification for all existing volumes.
222  * @nb: the notifier to call
223  *
224  * This function walks all UBI devices and volumes and sends the
225  * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
226  * registered notifiers are called, otherwise only the @nb notifier is called.
227  * Returns the number of sent notifications.
228  */
229 int ubi_enumerate_volumes(struct notifier_block *nb)
230 {
231 	int i, count = 0;
232 
233 	/*
234 	 * Since the @ubi_devices_mutex is locked, and we are not going to
235 	 * change @ubi_devices, we do not have to lock @ubi_devices_lock.
236 	 */
237 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
238 		struct ubi_device *ubi = ubi_devices[i];
239 
240 		if (!ubi)
241 			continue;
242 		count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
243 	}
244 
245 	return count;
246 }
247 
248 /**
249  * ubi_get_device - get UBI device.
250  * @ubi_num: UBI device number
251  *
252  * This function returns UBI device description object for UBI device number
253  * @ubi_num, or %NULL if the device does not exist. This function increases the
254  * device reference count to prevent removal of the device. In other words, the
255  * device cannot be removed if its reference count is not zero.
256  */
257 struct ubi_device *ubi_get_device(int ubi_num)
258 {
259 	struct ubi_device *ubi;
260 
261 	spin_lock(&ubi_devices_lock);
262 	ubi = ubi_devices[ubi_num];
263 	if (ubi) {
264 		ubi_assert(ubi->ref_count >= 0);
265 		ubi->ref_count += 1;
266 		get_device(&ubi->dev);
267 	}
268 	spin_unlock(&ubi_devices_lock);
269 
270 	return ubi;
271 }
272 
273 /**
274  * ubi_put_device - drop an UBI device reference.
275  * @ubi: UBI device description object
276  */
277 void ubi_put_device(struct ubi_device *ubi)
278 {
279 	spin_lock(&ubi_devices_lock);
280 	ubi->ref_count -= 1;
281 	put_device(&ubi->dev);
282 	spin_unlock(&ubi_devices_lock);
283 }
284 
285 /**
286  * ubi_get_by_major - get UBI device by character device major number.
287  * @major: major number
288  *
289  * This function is similar to 'ubi_get_device()', but it searches the device
290  * by its major number.
291  */
292 struct ubi_device *ubi_get_by_major(int major)
293 {
294 	int i;
295 	struct ubi_device *ubi;
296 
297 	spin_lock(&ubi_devices_lock);
298 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
299 		ubi = ubi_devices[i];
300 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
301 			ubi_assert(ubi->ref_count >= 0);
302 			ubi->ref_count += 1;
303 			get_device(&ubi->dev);
304 			spin_unlock(&ubi_devices_lock);
305 			return ubi;
306 		}
307 	}
308 	spin_unlock(&ubi_devices_lock);
309 
310 	return NULL;
311 }
312 
313 /**
314  * ubi_major2num - get UBI device number by character device major number.
315  * @major: major number
316  *
317  * This function searches UBI device number object by its major number. If UBI
318  * device was not found, this function returns -ENODEV, otherwise the UBI device
319  * number is returned.
320  */
321 int ubi_major2num(int major)
322 {
323 	int i, ubi_num = -ENODEV;
324 
325 	spin_lock(&ubi_devices_lock);
326 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
327 		struct ubi_device *ubi = ubi_devices[i];
328 
329 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
330 			ubi_num = ubi->ubi_num;
331 			break;
332 		}
333 	}
334 	spin_unlock(&ubi_devices_lock);
335 
336 	return ubi_num;
337 }
338 
339 /* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
340 static ssize_t dev_attribute_show(struct device *dev,
341 				  struct device_attribute *attr, char *buf)
342 {
343 	ssize_t ret;
344 	struct ubi_device *ubi;
345 
346 	/*
347 	 * The below code looks weird, but it actually makes sense. We get the
348 	 * UBI device reference from the contained 'struct ubi_device'. But it
349 	 * is unclear if the device was removed or not yet. Indeed, if the
350 	 * device was removed before we increased its reference count,
351 	 * 'ubi_get_device()' will return -ENODEV and we fail.
352 	 *
353 	 * Remember, 'struct ubi_device' is freed in the release function, so
354 	 * we still can use 'ubi->ubi_num'.
355 	 */
356 	ubi = container_of(dev, struct ubi_device, dev);
357 
358 	if (attr == &dev_eraseblock_size)
359 		ret = sprintf(buf, "%d\n", ubi->leb_size);
360 	else if (attr == &dev_avail_eraseblocks)
361 		ret = sprintf(buf, "%d\n", ubi->avail_pebs);
362 	else if (attr == &dev_total_eraseblocks)
363 		ret = sprintf(buf, "%d\n", ubi->good_peb_count);
364 	else if (attr == &dev_volumes_count)
365 		ret = sprintf(buf, "%d\n", ubi->vol_count - UBI_INT_VOL_COUNT);
366 	else if (attr == &dev_max_ec)
367 		ret = sprintf(buf, "%d\n", ubi->max_ec);
368 	else if (attr == &dev_reserved_for_bad)
369 		ret = sprintf(buf, "%d\n", ubi->beb_rsvd_pebs);
370 	else if (attr == &dev_bad_peb_count)
371 		ret = sprintf(buf, "%d\n", ubi->bad_peb_count);
372 	else if (attr == &dev_max_vol_count)
373 		ret = sprintf(buf, "%d\n", ubi->vtbl_slots);
374 	else if (attr == &dev_min_io_size)
375 		ret = sprintf(buf, "%d\n", ubi->min_io_size);
376 	else if (attr == &dev_bgt_enabled)
377 		ret = sprintf(buf, "%d\n", ubi->thread_enabled);
378 	else if (attr == &dev_mtd_num)
379 		ret = sprintf(buf, "%d\n", ubi->mtd->index);
380 	else if (attr == &dev_ro_mode)
381 		ret = sprintf(buf, "%d\n", ubi->ro_mode);
382 	else
383 		ret = -EINVAL;
384 
385 	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 				ubi->volumes[i] = NULL;
475 				goto out_volumes;
476 			}
477 		}
478 
479 	return 0;
480 
481 out_volumes:
482 	kill_volumes(ubi);
483 	cdev_device_del(&ubi->cdev, &ubi->dev);
484 out_unreg:
485 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
486 	ubi_err(ubi, "cannot initialize UBI %s, error %d",
487 		ubi->ubi_name, err);
488 	return err;
489 }
490 
491 /**
492  * uif_close - close user interfaces for an UBI device.
493  * @ubi: UBI device description object
494  *
495  * Note, since this function un-registers UBI volume device objects (@vol->dev),
496  * the memory allocated voe the volumes is freed as well (in the release
497  * function).
498  */
499 static void uif_close(struct ubi_device *ubi)
500 {
501 	kill_volumes(ubi);
502 	cdev_device_del(&ubi->cdev, &ubi->dev);
503 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
504 }
505 
506 /**
507  * ubi_free_volumes_from - free volumes from specific index.
508  * @ubi: UBI device description object
509  * @from: the start index used for volume free.
510  */
511 static void ubi_free_volumes_from(struct ubi_device *ubi, int from)
512 {
513 	int i;
514 
515 	for (i = from; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
516 		if (!ubi->volumes[i])
517 			continue;
518 		ubi_eba_replace_table(ubi->volumes[i], NULL);
519 		ubi_fastmap_destroy_checkmap(ubi->volumes[i]);
520 		kfree(ubi->volumes[i]);
521 		ubi->volumes[i] = NULL;
522 	}
523 }
524 
525 /**
526  * ubi_free_all_volumes - free all volumes.
527  * @ubi: UBI device description object
528  */
529 void ubi_free_all_volumes(struct ubi_device *ubi)
530 {
531 	ubi_free_volumes_from(ubi, 0);
532 }
533 
534 /**
535  * ubi_free_internal_volumes - free internal volumes.
536  * @ubi: UBI device description object
537  */
538 void ubi_free_internal_volumes(struct ubi_device *ubi)
539 {
540 	ubi_free_volumes_from(ubi, ubi->vtbl_slots);
541 }
542 
543 static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
544 {
545 	int limit, device_pebs;
546 	uint64_t device_size;
547 
548 	if (!max_beb_per1024) {
549 		/*
550 		 * Since max_beb_per1024 has not been set by the user in either
551 		 * the cmdline or Kconfig, use mtd_max_bad_blocks to set the
552 		 * limit if it is supported by the device.
553 		 */
554 		limit = mtd_max_bad_blocks(ubi->mtd, 0, ubi->mtd->size);
555 		if (limit < 0)
556 			return 0;
557 		return limit;
558 	}
559 
560 	/*
561 	 * Here we are using size of the entire flash chip and
562 	 * not just the MTD partition size because the maximum
563 	 * number of bad eraseblocks is a percentage of the
564 	 * whole device and bad eraseblocks are not fairly
565 	 * distributed over the flash chip. So the worst case
566 	 * is that all the bad eraseblocks of the chip are in
567 	 * the MTD partition we are attaching (ubi->mtd).
568 	 */
569 	device_size = mtd_get_device_size(ubi->mtd);
570 	device_pebs = mtd_div_by_eb(device_size, ubi->mtd);
571 	limit = mult_frac(device_pebs, max_beb_per1024, 1024);
572 
573 	/* Round it up */
574 	if (mult_frac(limit, 1024, max_beb_per1024) < device_pebs)
575 		limit += 1;
576 
577 	return limit;
578 }
579 
580 /**
581  * io_init - initialize I/O sub-system for a given UBI device.
582  * @ubi: UBI device description object
583  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
584  *
585  * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
586  * assumed:
587  *   o EC header is always at offset zero - this cannot be changed;
588  *   o VID header starts just after the EC header at the closest address
589  *     aligned to @io->hdrs_min_io_size;
590  *   o data starts just after the VID header at the closest address aligned to
591  *     @io->min_io_size
592  *
593  * This function returns zero in case of success and a negative error code in
594  * case of failure.
595  */
596 static int io_init(struct ubi_device *ubi, int max_beb_per1024)
597 {
598 	dbg_gen("sizeof(struct ubi_ainf_peb) %zu", sizeof(struct ubi_ainf_peb));
599 	dbg_gen("sizeof(struct ubi_wl_entry) %zu", sizeof(struct ubi_wl_entry));
600 
601 	if (ubi->mtd->numeraseregions != 0) {
602 		/*
603 		 * Some flashes have several erase regions. Different regions
604 		 * may have different eraseblock size and other
605 		 * characteristics. It looks like mostly multi-region flashes
606 		 * have one "main" region and one or more small regions to
607 		 * store boot loader code or boot parameters or whatever. I
608 		 * guess we should just pick the largest region. But this is
609 		 * not implemented.
610 		 */
611 		ubi_err(ubi, "multiple regions, not implemented");
612 		return -EINVAL;
613 	}
614 
615 	if (ubi->vid_hdr_offset < 0)
616 		return -EINVAL;
617 
618 	/*
619 	 * Note, in this implementation we support MTD devices with 0x7FFFFFFF
620 	 * physical eraseblocks maximum.
621 	 */
622 
623 	ubi->peb_size   = ubi->mtd->erasesize;
624 	ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
625 	ubi->flash_size = ubi->mtd->size;
626 
627 	if (mtd_can_have_bb(ubi->mtd)) {
628 		ubi->bad_allowed = 1;
629 		ubi->bad_peb_limit = get_bad_peb_limit(ubi, max_beb_per1024);
630 	}
631 
632 	if (ubi->mtd->type == MTD_NORFLASH)
633 		ubi->nor_flash = 1;
634 
635 	ubi->min_io_size = ubi->mtd->writesize;
636 	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
637 
638 	/*
639 	 * Make sure minimal I/O unit is power of 2. Note, there is no
640 	 * fundamental reason for this assumption. It is just an optimization
641 	 * which allows us to avoid costly division operations.
642 	 */
643 	if (!is_power_of_2(ubi->min_io_size)) {
644 		ubi_err(ubi, "min. I/O unit (%d) is not power of 2",
645 			ubi->min_io_size);
646 		return -EINVAL;
647 	}
648 
649 	ubi_assert(ubi->hdrs_min_io_size > 0);
650 	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
651 	ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
652 
653 	ubi->max_write_size = ubi->mtd->writebufsize;
654 	/*
655 	 * Maximum write size has to be greater or equivalent to min. I/O
656 	 * size, and be multiple of min. I/O size.
657 	 */
658 	if (ubi->max_write_size < ubi->min_io_size ||
659 	    ubi->max_write_size % ubi->min_io_size ||
660 	    !is_power_of_2(ubi->max_write_size)) {
661 		ubi_err(ubi, "bad write buffer size %d for %d min. I/O unit",
662 			ubi->max_write_size, ubi->min_io_size);
663 		return -EINVAL;
664 	}
665 
666 	/* Calculate default aligned sizes of EC and VID headers */
667 	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
668 	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
669 
670 	dbg_gen("min_io_size      %d", ubi->min_io_size);
671 	dbg_gen("max_write_size   %d", ubi->max_write_size);
672 	dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
673 	dbg_gen("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
674 	dbg_gen("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
675 
676 	if (ubi->vid_hdr_offset == 0)
677 		/* Default offset */
678 		ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
679 				      ubi->ec_hdr_alsize;
680 	else {
681 		ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
682 						~(ubi->hdrs_min_io_size - 1);
683 		ubi->vid_hdr_shift = ubi->vid_hdr_offset -
684 						ubi->vid_hdr_aloffset;
685 	}
686 
687 	/*
688 	 * Memory allocation for VID header is ubi->vid_hdr_alsize
689 	 * which is described in comments in io.c.
690 	 * Make sure VID header shift + UBI_VID_HDR_SIZE not exceeds
691 	 * ubi->vid_hdr_alsize, so that all vid header operations
692 	 * won't access memory out of bounds.
693 	 */
694 	if ((ubi->vid_hdr_shift + UBI_VID_HDR_SIZE) > ubi->vid_hdr_alsize) {
695 		ubi_err(ubi, "Invalid VID header offset %d, VID header shift(%d)"
696 			" + VID header size(%zu) > VID header aligned size(%d).",
697 			ubi->vid_hdr_offset, ubi->vid_hdr_shift,
698 			UBI_VID_HDR_SIZE, ubi->vid_hdr_alsize);
699 		return -EINVAL;
700 	}
701 
702 	/* Similar for the data offset */
703 	ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
704 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
705 
706 	dbg_gen("vid_hdr_offset   %d", ubi->vid_hdr_offset);
707 	dbg_gen("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
708 	dbg_gen("vid_hdr_shift    %d", ubi->vid_hdr_shift);
709 	dbg_gen("leb_start        %d", ubi->leb_start);
710 
711 	/* The shift must be aligned to 32-bit boundary */
712 	if (ubi->vid_hdr_shift % 4) {
713 		ubi_err(ubi, "unaligned VID header shift %d",
714 			ubi->vid_hdr_shift);
715 		return -EINVAL;
716 	}
717 
718 	/* Check sanity */
719 	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
720 	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
721 	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
722 	    ubi->leb_start & (ubi->min_io_size - 1)) {
723 		ubi_err(ubi, "bad VID header (%d) or data offsets (%d)",
724 			ubi->vid_hdr_offset, ubi->leb_start);
725 		return -EINVAL;
726 	}
727 
728 	/*
729 	 * Set maximum amount of physical erroneous eraseblocks to be 10%.
730 	 * Erroneous PEB are those which have read errors.
731 	 */
732 	ubi->max_erroneous = ubi->peb_count / 10;
733 	if (ubi->max_erroneous < 16)
734 		ubi->max_erroneous = 16;
735 	dbg_gen("max_erroneous    %d", ubi->max_erroneous);
736 
737 	/*
738 	 * It may happen that EC and VID headers are situated in one minimal
739 	 * I/O unit. In this case we can only accept this UBI image in
740 	 * read-only mode.
741 	 */
742 	if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
743 		ubi_warn(ubi, "EC and VID headers are in the same minimal I/O unit, switch to read-only mode");
744 		ubi->ro_mode = 1;
745 	}
746 
747 	ubi->leb_size = ubi->peb_size - ubi->leb_start;
748 
749 	if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
750 		ubi_msg(ubi, "MTD device %d is write-protected, attach in read-only mode",
751 			ubi->mtd->index);
752 		ubi->ro_mode = 1;
753 	}
754 
755 	/*
756 	 * Note, ideally, we have to initialize @ubi->bad_peb_count here. But
757 	 * unfortunately, MTD does not provide this information. We should loop
758 	 * over all physical eraseblocks and invoke mtd->block_is_bad() for
759 	 * each physical eraseblock. So, we leave @ubi->bad_peb_count
760 	 * uninitialized so far.
761 	 */
762 
763 	return 0;
764 }
765 
766 /**
767  * autoresize - re-size the volume which has the "auto-resize" flag set.
768  * @ubi: UBI device description object
769  * @vol_id: ID of the volume to re-size
770  *
771  * This function re-sizes the volume marked by the %UBI_VTBL_AUTORESIZE_FLG in
772  * the volume table to the largest possible size. See comments in ubi-header.h
773  * for more description of the flag. Returns zero in case of success and a
774  * negative error code in case of failure.
775  */
776 static int autoresize(struct ubi_device *ubi, int vol_id)
777 {
778 	struct ubi_volume_desc desc;
779 	struct ubi_volume *vol = ubi->volumes[vol_id];
780 	int err, old_reserved_pebs = vol->reserved_pebs;
781 
782 	if (ubi->ro_mode) {
783 		ubi_warn(ubi, "skip auto-resize because of R/O mode");
784 		return 0;
785 	}
786 
787 	/*
788 	 * Clear the auto-resize flag in the volume in-memory copy of the
789 	 * volume table, and 'ubi_resize_volume()' will propagate this change
790 	 * to the flash.
791 	 */
792 	ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;
793 
794 	if (ubi->avail_pebs == 0) {
795 		struct ubi_vtbl_record vtbl_rec;
796 
797 		/*
798 		 * No available PEBs to re-size the volume, clear the flag on
799 		 * flash and exit.
800 		 */
801 		vtbl_rec = ubi->vtbl[vol_id];
802 		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
803 		if (err)
804 			ubi_err(ubi, "cannot clean auto-resize flag for volume %d",
805 				vol_id);
806 	} else {
807 		desc.vol = vol;
808 		err = ubi_resize_volume(&desc,
809 					old_reserved_pebs + ubi->avail_pebs);
810 		if (err)
811 			ubi_err(ubi, "cannot auto-resize volume %d",
812 				vol_id);
813 	}
814 
815 	if (err)
816 		return err;
817 
818 	ubi_msg(ubi, "volume %d (\"%s\") re-sized from %d to %d LEBs",
819 		vol_id, vol->name, old_reserved_pebs, vol->reserved_pebs);
820 	return 0;
821 }
822 
823 /**
824  * ubi_attach_mtd_dev - attach an MTD device.
825  * @mtd: MTD device description object
826  * @ubi_num: number to assign to the new UBI device
827  * @vid_hdr_offset: VID header offset
828  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
829  * @disable_fm: whether disable fastmap
830  * @need_resv_pool: whether reserve pebs to fill fm_pool
831  *
832  * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
833  * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
834  * which case this function finds a vacant device number and assigns it
835  * automatically. Returns the new UBI device number in case of success and a
836  * negative error code in case of failure.
837  *
838  * If @disable_fm is true, ubi doesn't create new fastmap even the module param
839  * 'fm_autoconvert' is set, and existed old fastmap will be destroyed after
840  * doing full scanning.
841  *
842  * Note, the invocations of this function has to be serialized by the
843  * @ubi_devices_mutex.
844  */
845 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
846 		       int vid_hdr_offset, int max_beb_per1024, bool disable_fm,
847 		       bool need_resv_pool)
848 {
849 	struct ubi_device *ubi;
850 	int i, err;
851 
852 	if (max_beb_per1024 < 0 || max_beb_per1024 > MAX_MTD_UBI_BEB_LIMIT)
853 		return -EINVAL;
854 
855 	if (!max_beb_per1024)
856 		max_beb_per1024 = CONFIG_MTD_UBI_BEB_LIMIT;
857 
858 	/*
859 	 * Check if we already have the same MTD device attached.
860 	 *
861 	 * Note, this function assumes that UBI devices creations and deletions
862 	 * are serialized, so it does not take the &ubi_devices_lock.
863 	 */
864 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
865 		ubi = ubi_devices[i];
866 		if (ubi && mtd->index == ubi->mtd->index) {
867 			pr_err("ubi: mtd%d is already attached to ubi%d\n",
868 				mtd->index, i);
869 			return -EEXIST;
870 		}
871 	}
872 
873 	/*
874 	 * Make sure this MTD device is not emulated on top of an UBI volume
875 	 * already. Well, generally this recursion works fine, but there are
876 	 * different problems like the UBI module takes a reference to itself
877 	 * by attaching (and thus, opening) the emulated MTD device. This
878 	 * results in inability to unload the module. And in general it makes
879 	 * no sense to attach emulated MTD devices, so we prohibit this.
880 	 */
881 	if (mtd->type == MTD_UBIVOLUME) {
882 		pr_err("ubi: refuse attaching mtd%d - it is already emulated on top of UBI\n",
883 			mtd->index);
884 		return -EINVAL;
885 	}
886 
887 	/*
888 	 * Both UBI and UBIFS have been designed for SLC NAND and NOR flashes.
889 	 * MLC NAND is different and needs special care, otherwise UBI or UBIFS
890 	 * will die soon and you will lose all your data.
891 	 * Relax this rule if the partition we're attaching to operates in SLC
892 	 * mode.
893 	 */
894 	if (mtd->type == MTD_MLCNANDFLASH &&
895 	    !(mtd->flags & MTD_SLC_ON_MLC_EMULATION)) {
896 		pr_err("ubi: refuse attaching mtd%d - MLC NAND is not supported\n",
897 			mtd->index);
898 		return -EINVAL;
899 	}
900 
901 	/* UBI cannot work on flashes with zero erasesize. */
902 	if (!mtd->erasesize) {
903 		pr_err("ubi: refuse attaching mtd%d - zero erasesize flash is not supported\n",
904 			mtd->index);
905 		return -EINVAL;
906 	}
907 
908 	if (ubi_num == UBI_DEV_NUM_AUTO) {
909 		/* Search for an empty slot in the @ubi_devices array */
910 		for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
911 			if (!ubi_devices[ubi_num])
912 				break;
913 		if (ubi_num == UBI_MAX_DEVICES) {
914 			pr_err("ubi: only %d UBI devices may be created\n",
915 				UBI_MAX_DEVICES);
916 			return -ENFILE;
917 		}
918 	} else {
919 		if (ubi_num >= UBI_MAX_DEVICES)
920 			return -EINVAL;
921 
922 		/* Make sure ubi_num is not busy */
923 		if (ubi_devices[ubi_num]) {
924 			pr_err("ubi: ubi%i already exists\n", ubi_num);
925 			return -EEXIST;
926 		}
927 	}
928 
929 	ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
930 	if (!ubi)
931 		return -ENOMEM;
932 
933 	device_initialize(&ubi->dev);
934 	ubi->dev.release = dev_release;
935 	ubi->dev.class = &ubi_class;
936 	ubi->dev.groups = ubi_dev_groups;
937 	ubi->dev.parent = &mtd->dev;
938 
939 	ubi->mtd = mtd;
940 	ubi->ubi_num = ubi_num;
941 	ubi->vid_hdr_offset = vid_hdr_offset;
942 	ubi->autoresize_vol_id = -1;
943 
944 #ifdef CONFIG_MTD_UBI_FASTMAP
945 	ubi->fm_pool.used = ubi->fm_pool.size = 0;
946 	ubi->fm_wl_pool.used = ubi->fm_wl_pool.size = 0;
947 
948 	/*
949 	 * fm_pool.max_size is 5% of the total number of PEBs but it's also
950 	 * between UBI_FM_MAX_POOL_SIZE and UBI_FM_MIN_POOL_SIZE.
951 	 */
952 	ubi->fm_pool.max_size = min(((int)mtd_div_by_eb(ubi->mtd->size,
953 		ubi->mtd) / 100) * 5, UBI_FM_MAX_POOL_SIZE);
954 	ubi->fm_pool.max_size = max(ubi->fm_pool.max_size,
955 		UBI_FM_MIN_POOL_SIZE);
956 
957 	ubi->fm_wl_pool.max_size = ubi->fm_pool.max_size / 2;
958 	ubi->fm_pool_rsv_cnt = need_resv_pool ? ubi->fm_pool.max_size : 0;
959 	ubi->fm_disabled = (!fm_autoconvert || disable_fm) ? 1 : 0;
960 	if (fm_debug)
961 		ubi_enable_dbg_chk_fastmap(ubi);
962 
963 	if (!ubi->fm_disabled && (int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd)
964 	    <= UBI_FM_MAX_START) {
965 		ubi_err(ubi, "More than %i PEBs are needed for fastmap, sorry.",
966 			UBI_FM_MAX_START);
967 		ubi->fm_disabled = 1;
968 	}
969 
970 	ubi_msg(ubi, "default fastmap pool size: %d", ubi->fm_pool.max_size);
971 	ubi_msg(ubi, "default fastmap WL pool size: %d",
972 		ubi->fm_wl_pool.max_size);
973 #else
974 	ubi->fm_disabled = 1;
975 #endif
976 	mutex_init(&ubi->buf_mutex);
977 	mutex_init(&ubi->ckvol_mutex);
978 	mutex_init(&ubi->device_mutex);
979 	spin_lock_init(&ubi->volumes_lock);
980 	init_rwsem(&ubi->fm_protect);
981 	init_rwsem(&ubi->fm_eba_sem);
982 
983 	ubi_msg(ubi, "attaching mtd%d", mtd->index);
984 
985 	err = io_init(ubi, max_beb_per1024);
986 	if (err)
987 		goto out_free;
988 
989 	err = -ENOMEM;
990 	ubi->peb_buf = vmalloc(ubi->peb_size);
991 	if (!ubi->peb_buf)
992 		goto out_free;
993 
994 #ifdef CONFIG_MTD_UBI_FASTMAP
995 	ubi->fm_size = ubi_calc_fm_size(ubi);
996 	ubi->fm_buf = vzalloc(ubi->fm_size);
997 	if (!ubi->fm_buf)
998 		goto out_free;
999 #endif
1000 	err = ubi_attach(ubi, disable_fm ? 1 : 0);
1001 	if (err) {
1002 		ubi_err(ubi, "failed to attach mtd%d, error %d",
1003 			mtd->index, err);
1004 		goto out_free;
1005 	}
1006 
1007 	if (ubi->autoresize_vol_id != -1) {
1008 		err = autoresize(ubi, ubi->autoresize_vol_id);
1009 		if (err)
1010 			goto out_detach;
1011 	}
1012 
1013 	err = uif_init(ubi);
1014 	if (err)
1015 		goto out_detach;
1016 
1017 	err = ubi_debugfs_init_dev(ubi);
1018 	if (err)
1019 		goto out_uif;
1020 
1021 	ubi->bgt_thread = kthread_create(ubi_thread, ubi, "%s", ubi->bgt_name);
1022 	if (IS_ERR(ubi->bgt_thread)) {
1023 		err = PTR_ERR(ubi->bgt_thread);
1024 		ubi_err(ubi, "cannot spawn \"%s\", error %d",
1025 			ubi->bgt_name, err);
1026 		goto out_debugfs;
1027 	}
1028 
1029 	ubi_msg(ubi, "attached mtd%d (name \"%s\", size %llu MiB)",
1030 		mtd->index, mtd->name, ubi->flash_size >> 20);
1031 	ubi_msg(ubi, "PEB size: %d bytes (%d KiB), LEB size: %d bytes",
1032 		ubi->peb_size, ubi->peb_size >> 10, ubi->leb_size);
1033 	ubi_msg(ubi, "min./max. I/O unit sizes: %d/%d, sub-page size %d",
1034 		ubi->min_io_size, ubi->max_write_size, ubi->hdrs_min_io_size);
1035 	ubi_msg(ubi, "VID header offset: %d (aligned %d), data offset: %d",
1036 		ubi->vid_hdr_offset, ubi->vid_hdr_aloffset, ubi->leb_start);
1037 	ubi_msg(ubi, "good PEBs: %d, bad PEBs: %d, corrupted PEBs: %d",
1038 		ubi->good_peb_count, ubi->bad_peb_count, ubi->corr_peb_count);
1039 	ubi_msg(ubi, "user volume: %d, internal volumes: %d, max. volumes count: %d",
1040 		ubi->vol_count - UBI_INT_VOL_COUNT, UBI_INT_VOL_COUNT,
1041 		ubi->vtbl_slots);
1042 	ubi_msg(ubi, "max/mean erase counter: %d/%d, WL threshold: %d, image sequence number: %u",
1043 		ubi->max_ec, ubi->mean_ec, CONFIG_MTD_UBI_WL_THRESHOLD,
1044 		ubi->image_seq);
1045 	ubi_msg(ubi, "available PEBs: %d, total reserved PEBs: %d, PEBs reserved for bad PEB handling: %d",
1046 		ubi->avail_pebs, ubi->rsvd_pebs, ubi->beb_rsvd_pebs);
1047 
1048 	/*
1049 	 * The below lock makes sure we do not race with 'ubi_thread()' which
1050 	 * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
1051 	 */
1052 	spin_lock(&ubi->wl_lock);
1053 	ubi->thread_enabled = 1;
1054 	wake_up_process(ubi->bgt_thread);
1055 	spin_unlock(&ubi->wl_lock);
1056 
1057 	ubi_devices[ubi_num] = ubi;
1058 	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
1059 	return ubi_num;
1060 
1061 out_debugfs:
1062 	ubi_debugfs_exit_dev(ubi);
1063 out_uif:
1064 	uif_close(ubi);
1065 out_detach:
1066 	ubi_wl_close(ubi);
1067 	ubi_free_all_volumes(ubi);
1068 	vfree(ubi->vtbl);
1069 out_free:
1070 	vfree(ubi->peb_buf);
1071 	vfree(ubi->fm_buf);
1072 	put_device(&ubi->dev);
1073 	return err;
1074 }
1075 
1076 /**
1077  * ubi_detach_mtd_dev - detach an MTD device.
1078  * @ubi_num: UBI device number to detach from
1079  * @anyway: detach MTD even if device reference count is not zero
1080  *
1081  * This function destroys an UBI device number @ubi_num and detaches the
1082  * underlying MTD device. Returns zero in case of success and %-EBUSY if the
1083  * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
1084  * exist.
1085  *
1086  * Note, the invocations of this function has to be serialized by the
1087  * @ubi_devices_mutex.
1088  */
1089 int ubi_detach_mtd_dev(int ubi_num, int anyway)
1090 {
1091 	struct ubi_device *ubi;
1092 
1093 	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
1094 		return -EINVAL;
1095 
1096 	ubi = ubi_get_device(ubi_num);
1097 	if (!ubi)
1098 		return -EINVAL;
1099 
1100 	spin_lock(&ubi_devices_lock);
1101 	put_device(&ubi->dev);
1102 	ubi->ref_count -= 1;
1103 	if (ubi->ref_count) {
1104 		if (!anyway) {
1105 			spin_unlock(&ubi_devices_lock);
1106 			return -EBUSY;
1107 		}
1108 		/* This may only happen if there is a bug */
1109 		ubi_err(ubi, "%s reference count %d, destroy anyway",
1110 			ubi->ubi_name, ubi->ref_count);
1111 	}
1112 	ubi_devices[ubi_num] = NULL;
1113 	spin_unlock(&ubi_devices_lock);
1114 
1115 	ubi_assert(ubi_num == ubi->ubi_num);
1116 	ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
1117 	ubi_msg(ubi, "detaching mtd%d", ubi->mtd->index);
1118 #ifdef CONFIG_MTD_UBI_FASTMAP
1119 	/* If we don't write a new fastmap at detach time we lose all
1120 	 * EC updates that have been made since the last written fastmap.
1121 	 * In case of fastmap debugging we omit the update to simulate an
1122 	 * unclean shutdown. */
1123 	if (!ubi_dbg_chk_fastmap(ubi))
1124 		ubi_update_fastmap(ubi);
1125 #endif
1126 	/*
1127 	 * Before freeing anything, we have to stop the background thread to
1128 	 * prevent it from doing anything on this device while we are freeing.
1129 	 */
1130 	if (ubi->bgt_thread)
1131 		kthread_stop(ubi->bgt_thread);
1132 
1133 #ifdef CONFIG_MTD_UBI_FASTMAP
1134 	cancel_work_sync(&ubi->fm_work);
1135 #endif
1136 	ubi_debugfs_exit_dev(ubi);
1137 	uif_close(ubi);
1138 
1139 	ubi_wl_close(ubi);
1140 	ubi_free_internal_volumes(ubi);
1141 	vfree(ubi->vtbl);
1142 	vfree(ubi->peb_buf);
1143 	vfree(ubi->fm_buf);
1144 	ubi_msg(ubi, "mtd%d is detached", ubi->mtd->index);
1145 	put_mtd_device(ubi->mtd);
1146 	put_device(&ubi->dev);
1147 	return 0;
1148 }
1149 
1150 /**
1151  * open_mtd_by_chdev - open an MTD device by its character device node path.
1152  * @mtd_dev: MTD character device node path
1153  *
1154  * This helper function opens an MTD device by its character node device path.
1155  * Returns MTD device description object in case of success and a negative
1156  * error code in case of failure.
1157  */
1158 static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
1159 {
1160 	int err, minor;
1161 	struct path path;
1162 	struct kstat stat;
1163 
1164 	/* Probably this is an MTD character device node path */
1165 	err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
1166 	if (err)
1167 		return ERR_PTR(err);
1168 
1169 	err = vfs_getattr(&path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
1170 	path_put(&path);
1171 	if (err)
1172 		return ERR_PTR(err);
1173 
1174 	/* MTD device number is defined by the major / minor numbers */
1175 	if (MAJOR(stat.rdev) != MTD_CHAR_MAJOR || !S_ISCHR(stat.mode))
1176 		return ERR_PTR(-EINVAL);
1177 
1178 	minor = MINOR(stat.rdev);
1179 
1180 	if (minor & 1)
1181 		/*
1182 		 * Just do not think the "/dev/mtdrX" devices support is need,
1183 		 * so do not support them to avoid doing extra work.
1184 		 */
1185 		return ERR_PTR(-EINVAL);
1186 
1187 	return get_mtd_device(NULL, minor / 2);
1188 }
1189 
1190 /**
1191  * open_mtd_device - open MTD device by name, character device path, or number.
1192  * @mtd_dev: name, character device node path, or MTD device device number
1193  *
1194  * This function tries to open and MTD device described by @mtd_dev string,
1195  * which is first treated as ASCII MTD device number, and if it is not true, it
1196  * is treated as MTD device name, and if that is also not true, it is treated
1197  * as MTD character device node path. Returns MTD device description object in
1198  * case of success and a negative error code in case of failure.
1199  */
1200 static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
1201 {
1202 	struct mtd_info *mtd;
1203 	int mtd_num;
1204 	char *endp;
1205 
1206 	mtd_num = simple_strtoul(mtd_dev, &endp, 0);
1207 	if (*endp != '\0' || mtd_dev == endp) {
1208 		/*
1209 		 * This does not look like an ASCII integer, probably this is
1210 		 * MTD device name.
1211 		 */
1212 		mtd = get_mtd_device_nm(mtd_dev);
1213 		if (PTR_ERR(mtd) == -ENODEV)
1214 			/* Probably this is an MTD character device node path */
1215 			mtd = open_mtd_by_chdev(mtd_dev);
1216 	} else
1217 		mtd = get_mtd_device(NULL, mtd_num);
1218 
1219 	return mtd;
1220 }
1221 
1222 static int __init ubi_init(void)
1223 {
1224 	int err, i, k;
1225 
1226 	/* Ensure that EC and VID headers have correct size */
1227 	BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
1228 	BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);
1229 
1230 	if (mtd_devs > UBI_MAX_DEVICES) {
1231 		pr_err("UBI error: too many MTD devices, maximum is %d\n",
1232 		       UBI_MAX_DEVICES);
1233 		return -EINVAL;
1234 	}
1235 
1236 	/* Create base sysfs directory and sysfs files */
1237 	err = class_register(&ubi_class);
1238 	if (err < 0)
1239 		return err;
1240 
1241 	err = misc_register(&ubi_ctrl_cdev);
1242 	if (err) {
1243 		pr_err("UBI error: cannot register device\n");
1244 		goto out;
1245 	}
1246 
1247 	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
1248 					      sizeof(struct ubi_wl_entry),
1249 					      0, 0, NULL);
1250 	if (!ubi_wl_entry_slab) {
1251 		err = -ENOMEM;
1252 		goto out_dev_unreg;
1253 	}
1254 
1255 	err = ubi_debugfs_init();
1256 	if (err)
1257 		goto out_slab;
1258 
1259 
1260 	/* Attach MTD devices */
1261 	for (i = 0; i < mtd_devs; i++) {
1262 		struct mtd_dev_param *p = &mtd_dev_param[i];
1263 		struct mtd_info *mtd;
1264 
1265 		cond_resched();
1266 
1267 		mtd = open_mtd_device(p->name);
1268 		if (IS_ERR(mtd)) {
1269 			err = PTR_ERR(mtd);
1270 			pr_err("UBI error: cannot open mtd %s, error %d\n",
1271 			       p->name, err);
1272 			/* See comment below re-ubi_is_module(). */
1273 			if (ubi_is_module())
1274 				goto out_detach;
1275 			continue;
1276 		}
1277 
1278 		mutex_lock(&ubi_devices_mutex);
1279 		err = ubi_attach_mtd_dev(mtd, p->ubi_num,
1280 					 p->vid_hdr_offs, p->max_beb_per1024,
1281 					 p->enable_fm == 0,
1282 					 p->need_resv_pool != 0);
1283 		mutex_unlock(&ubi_devices_mutex);
1284 		if (err < 0) {
1285 			pr_err("UBI error: cannot attach mtd%d\n",
1286 			       mtd->index);
1287 			put_mtd_device(mtd);
1288 
1289 			/*
1290 			 * Originally UBI stopped initializing on any error.
1291 			 * However, later on it was found out that this
1292 			 * behavior is not very good when UBI is compiled into
1293 			 * the kernel and the MTD devices to attach are passed
1294 			 * through the command line. Indeed, UBI failure
1295 			 * stopped whole boot sequence.
1296 			 *
1297 			 * To fix this, we changed the behavior for the
1298 			 * non-module case, but preserved the old behavior for
1299 			 * the module case, just for compatibility. This is a
1300 			 * little inconsistent, though.
1301 			 */
1302 			if (ubi_is_module())
1303 				goto out_detach;
1304 		}
1305 	}
1306 
1307 	err = ubiblock_init();
1308 	if (err) {
1309 		pr_err("UBI error: block: cannot initialize, error %d\n", err);
1310 
1311 		/* See comment above re-ubi_is_module(). */
1312 		if (ubi_is_module())
1313 			goto out_detach;
1314 	}
1315 
1316 	return 0;
1317 
1318 out_detach:
1319 	for (k = 0; k < i; k++)
1320 		if (ubi_devices[k]) {
1321 			mutex_lock(&ubi_devices_mutex);
1322 			ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
1323 			mutex_unlock(&ubi_devices_mutex);
1324 		}
1325 	ubi_debugfs_exit();
1326 out_slab:
1327 	kmem_cache_destroy(ubi_wl_entry_slab);
1328 out_dev_unreg:
1329 	misc_deregister(&ubi_ctrl_cdev);
1330 out:
1331 	class_unregister(&ubi_class);
1332 	pr_err("UBI error: cannot initialize UBI, error %d\n", err);
1333 	return err;
1334 }
1335 late_initcall(ubi_init);
1336 
1337 static void __exit ubi_exit(void)
1338 {
1339 	int i;
1340 
1341 	ubiblock_exit();
1342 
1343 	for (i = 0; i < UBI_MAX_DEVICES; i++)
1344 		if (ubi_devices[i]) {
1345 			mutex_lock(&ubi_devices_mutex);
1346 			ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
1347 			mutex_unlock(&ubi_devices_mutex);
1348 		}
1349 	ubi_debugfs_exit();
1350 	kmem_cache_destroy(ubi_wl_entry_slab);
1351 	misc_deregister(&ubi_ctrl_cdev);
1352 	class_unregister(&ubi_class);
1353 }
1354 module_exit(ubi_exit);
1355 
1356 /**
1357  * bytes_str_to_int - convert a number of bytes string into an integer.
1358  * @str: the string to convert
1359  *
1360  * This function returns positive resulting integer in case of success and a
1361  * negative error code in case of failure.
1362  */
1363 static int bytes_str_to_int(const char *str)
1364 {
1365 	char *endp;
1366 	unsigned long result;
1367 
1368 	result = simple_strtoul(str, &endp, 0);
1369 	if (str == endp || result >= INT_MAX) {
1370 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1371 		return -EINVAL;
1372 	}
1373 
1374 	switch (*endp) {
1375 	case 'G':
1376 		result *= 1024;
1377 		fallthrough;
1378 	case 'M':
1379 		result *= 1024;
1380 		fallthrough;
1381 	case 'K':
1382 		result *= 1024;
1383 		break;
1384 	case '\0':
1385 		break;
1386 	default:
1387 		pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1388 		return -EINVAL;
1389 	}
1390 
1391 	return result;
1392 }
1393 
1394 /**
1395  * ubi_mtd_param_parse - parse the 'mtd=' UBI parameter.
1396  * @val: the parameter value to parse
1397  * @kp: not used
1398  *
1399  * This function returns zero in case of success and a negative error code in
1400  * case of error.
1401  */
1402 static int ubi_mtd_param_parse(const char *val, const struct kernel_param *kp)
1403 {
1404 	int i, len;
1405 	struct mtd_dev_param *p;
1406 	char buf[MTD_PARAM_LEN_MAX];
1407 	char *pbuf = &buf[0];
1408 	char *tokens[MTD_PARAM_MAX_COUNT], *token;
1409 
1410 	if (!val)
1411 		return -EINVAL;
1412 
1413 	if (mtd_devs == UBI_MAX_DEVICES) {
1414 		pr_err("UBI error: too many parameters, max. is %d\n",
1415 		       UBI_MAX_DEVICES);
1416 		return -EINVAL;
1417 	}
1418 
1419 	len = strnlen(val, MTD_PARAM_LEN_MAX);
1420 	if (len == MTD_PARAM_LEN_MAX) {
1421 		pr_err("UBI error: parameter \"%s\" is too long, max. is %d\n",
1422 		       val, MTD_PARAM_LEN_MAX);
1423 		return -EINVAL;
1424 	}
1425 
1426 	if (len == 0) {
1427 		pr_warn("UBI warning: empty 'mtd=' parameter - ignored\n");
1428 		return 0;
1429 	}
1430 
1431 	strcpy(buf, val);
1432 
1433 	/* Get rid of the final newline */
1434 	if (buf[len - 1] == '\n')
1435 		buf[len - 1] = '\0';
1436 
1437 	for (i = 0; i < MTD_PARAM_MAX_COUNT; i++)
1438 		tokens[i] = strsep(&pbuf, ",");
1439 
1440 	if (pbuf) {
1441 		pr_err("UBI error: too many arguments at \"%s\"\n", val);
1442 		return -EINVAL;
1443 	}
1444 
1445 	p = &mtd_dev_param[mtd_devs];
1446 	strcpy(&p->name[0], tokens[0]);
1447 
1448 	token = tokens[1];
1449 	if (token) {
1450 		p->vid_hdr_offs = bytes_str_to_int(token);
1451 
1452 		if (p->vid_hdr_offs < 0)
1453 			return p->vid_hdr_offs;
1454 	}
1455 
1456 	token = tokens[2];
1457 	if (token) {
1458 		int err = kstrtoint(token, 10, &p->max_beb_per1024);
1459 
1460 		if (err) {
1461 			pr_err("UBI error: bad value for max_beb_per1024 parameter: %s\n",
1462 			       token);
1463 			return -EINVAL;
1464 		}
1465 	}
1466 
1467 	token = tokens[3];
1468 	if (token) {
1469 		int err = kstrtoint(token, 10, &p->ubi_num);
1470 
1471 		if (err) {
1472 			pr_err("UBI error: bad value for ubi_num parameter: %s\n",
1473 			       token);
1474 			return -EINVAL;
1475 		}
1476 	} else
1477 		p->ubi_num = UBI_DEV_NUM_AUTO;
1478 
1479 	token = tokens[4];
1480 	if (token) {
1481 		int err = kstrtoint(token, 10, &p->enable_fm);
1482 
1483 		if (err) {
1484 			pr_err("UBI error: bad value for enable_fm parameter: %s\n",
1485 				token);
1486 			return -EINVAL;
1487 		}
1488 	} else
1489 		p->enable_fm = 0;
1490 
1491 	token = tokens[5];
1492 	if (token) {
1493 		int err = kstrtoint(token, 10, &p->need_resv_pool);
1494 
1495 		if (err) {
1496 			pr_err("UBI error: bad value for need_resv_pool parameter: %s\n",
1497 				token);
1498 			return -EINVAL;
1499 		}
1500 	} else
1501 		p->need_resv_pool = 0;
1502 
1503 	mtd_devs += 1;
1504 	return 0;
1505 }
1506 
1507 module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 0400);
1508 MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024[,ubi_num]]].\n"
1509 		      "Multiple \"mtd\" parameters may be specified.\n"
1510 		      "MTD devices may be specified by their number, name, or path to the MTD character device node.\n"
1511 		      "Optional \"vid_hdr_offs\" parameter specifies UBI VID header position to be used by UBI. (default value if 0)\n"
1512 		      "Optional \"max_beb_per1024\" parameter specifies the maximum expected bad eraseblock per 1024 eraseblocks. (default value ("
1513 		      __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0)\n"
1514 		      "Optional \"ubi_num\" parameter specifies UBI device number which have to be assigned to the newly created UBI device (assigned automatically by default)\n"
1515 		      "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"
1516 		      "Optional \"need_resv_pool\" parameter determines whether to reserve pool->max_size pebs during attach. If the value is non-zero, peb reservation is enabled. Default value is 0.\n"
1517 		      "\n"
1518 		      "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
1519 		      "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"
1520 		      "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"
1521 		      "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"
1522 		      "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"
1523 		      "\t(e.g. if the NAND *chipset* has 4096 PEB, 100 will be reserved for this UBI device).");
1524 #ifdef CONFIG_MTD_UBI_FASTMAP
1525 module_param(fm_autoconvert, bool, 0644);
1526 MODULE_PARM_DESC(fm_autoconvert, "Set this parameter to enable fastmap automatically on images without a fastmap.");
1527 module_param(fm_debug, bool, 0);
1528 MODULE_PARM_DESC(fm_debug, "Set this parameter to enable fastmap debugging by default. Warning, this will make fastmap slow!");
1529 #endif
1530 MODULE_VERSION(__stringify(UBI_VERSION));
1531 MODULE_DESCRIPTION("UBI - Unsorted Block Images");
1532 MODULE_AUTHOR("Artem Bityutskiy");
1533 MODULE_LICENSE("GPL");
1534