xref: /openbmc/linux/drivers/mtd/ubi/build.c (revision db181ce0)
1 /*
2  * Copyright (c) International Business Machines Corp., 2006
3  * Copyright (c) Nokia Corporation, 2007
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13  * the GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18  *
19  * Author: Artem Bityutskiy (Битюцкий Артём),
20  *         Frank Haverkamp
21  */
22 
23 /*
24  * This file includes UBI initialization and building of UBI devices.
25  *
26  * When UBI is initialized, it attaches all the MTD devices specified as the
27  * module load parameters or the kernel boot parameters. If MTD devices were
28  * specified, UBI does not attach any MTD device, but it is possible to do
29  * later using the "UBI control device".
30  */
31 
32 #include <linux/err.h>
33 #include <linux/module.h>
34 #include <linux/moduleparam.h>
35 #include <linux/stringify.h>
36 #include <linux/namei.h>
37 #include <linux/stat.h>
38 #include <linux/miscdevice.h>
39 #include <linux/mtd/partitions.h>
40 #include <linux/log2.h>
41 #include <linux/kthread.h>
42 #include <linux/kernel.h>
43 #include <linux/slab.h>
44 #include <linux/major.h>
45 #include "ubi.h"
46 
47 /* Maximum length of the 'mtd=' parameter */
48 #define MTD_PARAM_LEN_MAX 64
49 
50 /* Maximum number of comma-separated items in the 'mtd=' parameter */
51 #define MTD_PARAM_MAX_COUNT 4
52 
53 /* Maximum value for the number of bad PEBs per 1024 PEBs */
54 #define MAX_MTD_UBI_BEB_LIMIT 768
55 
56 #ifdef CONFIG_MTD_UBI_MODULE
57 #define ubi_is_module() 1
58 #else
59 #define ubi_is_module() 0
60 #endif
61 
62 /**
63  * struct mtd_dev_param - MTD device parameter description data structure.
64  * @name: MTD character device node path, MTD device name, or MTD device number
65  *        string
66  * @vid_hdr_offs: VID header offset
67  * @max_beb_per1024: maximum expected number of bad PEBs per 1024 PEBs
68  */
69 struct mtd_dev_param {
70 	char name[MTD_PARAM_LEN_MAX];
71 	int ubi_num;
72 	int vid_hdr_offs;
73 	int max_beb_per1024;
74 };
75 
76 /* Numbers of elements set in the @mtd_dev_param array */
77 static int __initdata mtd_devs;
78 
79 /* MTD devices specification parameters */
80 static struct mtd_dev_param __initdata mtd_dev_param[UBI_MAX_DEVICES];
81 #ifdef CONFIG_MTD_UBI_FASTMAP
82 /* UBI module parameter to enable fastmap automatically on non-fastmap images */
83 static bool fm_autoconvert;
84 #endif
85 /* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
86 struct class *ubi_class;
87 
88 /* Slab cache for wear-leveling entries */
89 struct kmem_cache *ubi_wl_entry_slab;
90 
91 /* UBI control character device */
92 static struct miscdevice ubi_ctrl_cdev = {
93 	.minor = MISC_DYNAMIC_MINOR,
94 	.name = "ubi_ctrl",
95 	.fops = &ubi_ctrl_cdev_operations,
96 };
97 
98 /* All UBI devices in system */
99 static struct ubi_device *ubi_devices[UBI_MAX_DEVICES];
100 
101 /* Serializes UBI devices creations and removals */
102 DEFINE_MUTEX(ubi_devices_mutex);
103 
104 /* Protects @ubi_devices and @ubi->ref_count */
105 static DEFINE_SPINLOCK(ubi_devices_lock);
106 
107 /* "Show" method for files in '/<sysfs>/class/ubi/' */
108 static ssize_t ubi_version_show(struct class *class,
109 				struct class_attribute *attr, char *buf)
110 {
111 	return sprintf(buf, "%d\n", UBI_VERSION);
112 }
113 
114 /* UBI version attribute ('/<sysfs>/class/ubi/version') */
115 static struct class_attribute ubi_version =
116 	__ATTR(version, S_IRUGO, ubi_version_show, NULL);
117 
118 static ssize_t dev_attribute_show(struct device *dev,
119 				  struct device_attribute *attr, char *buf);
120 
121 /* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
122 static struct device_attribute dev_eraseblock_size =
123 	__ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
124 static struct device_attribute dev_avail_eraseblocks =
125 	__ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
126 static struct device_attribute dev_total_eraseblocks =
127 	__ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
128 static struct device_attribute dev_volumes_count =
129 	__ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
130 static struct device_attribute dev_max_ec =
131 	__ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
132 static struct device_attribute dev_reserved_for_bad =
133 	__ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
134 static struct device_attribute dev_bad_peb_count =
135 	__ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
136 static struct device_attribute dev_max_vol_count =
137 	__ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
138 static struct device_attribute dev_min_io_size =
139 	__ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
140 static struct device_attribute dev_bgt_enabled =
141 	__ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);
142 static struct device_attribute dev_mtd_num =
143 	__ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
144 
145 /**
146  * ubi_volume_notify - send a volume change notification.
147  * @ubi: UBI device description object
148  * @vol: volume description object of the changed volume
149  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
150  *
151  * This is a helper function which notifies all subscribers about a volume
152  * change event (creation, removal, re-sizing, re-naming, updating). Returns
153  * zero in case of success and a negative error code in case of failure.
154  */
155 int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
156 {
157 	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 #ifdef CONFIG_MTD_UBI_FASTMAP
163 	switch (ntype) {
164 	case UBI_VOLUME_ADDED:
165 	case UBI_VOLUME_REMOVED:
166 	case UBI_VOLUME_RESIZED:
167 	case UBI_VOLUME_RENAMED:
168 		if (ubi_update_fastmap(ubi)) {
169 			ubi_err("Unable to update fastmap!");
170 			ubi_ro_mode(ubi);
171 		}
172 	}
173 #endif
174 	return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
175 }
176 
177 /**
178  * ubi_notify_all - send a notification to all volumes.
179  * @ubi: UBI device description object
180  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
181  * @nb: the notifier to call
182  *
183  * This function walks all volumes of UBI device @ubi and sends the @ntype
184  * notification for each volume. If @nb is %NULL, then all registered notifiers
185  * are called, otherwise only the @nb notifier is called. Returns the number of
186  * sent notifications.
187  */
188 int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
189 {
190 	struct ubi_notification nt;
191 	int i, count = 0;
192 
193 	ubi_do_get_device_info(ubi, &nt.di);
194 
195 	mutex_lock(&ubi->device_mutex);
196 	for (i = 0; i < ubi->vtbl_slots; i++) {
197 		/*
198 		 * Since the @ubi->device is locked, and we are not going to
199 		 * change @ubi->volumes, we do not have to lock
200 		 * @ubi->volumes_lock.
201 		 */
202 		if (!ubi->volumes[i])
203 			continue;
204 
205 		ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
206 		if (nb)
207 			nb->notifier_call(nb, ntype, &nt);
208 		else
209 			blocking_notifier_call_chain(&ubi_notifiers, ntype,
210 						     &nt);
211 		count += 1;
212 	}
213 	mutex_unlock(&ubi->device_mutex);
214 
215 	return count;
216 }
217 
218 /**
219  * ubi_enumerate_volumes - send "add" notification for all existing volumes.
220  * @nb: the notifier to call
221  *
222  * This function walks all UBI devices and volumes and sends the
223  * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
224  * registered notifiers are called, otherwise only the @nb notifier is called.
225  * Returns the number of sent notifications.
226  */
227 int ubi_enumerate_volumes(struct notifier_block *nb)
228 {
229 	int i, count = 0;
230 
231 	/*
232 	 * Since the @ubi_devices_mutex is locked, and we are not going to
233 	 * change @ubi_devices, we do not have to lock @ubi_devices_lock.
234 	 */
235 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
236 		struct ubi_device *ubi = ubi_devices[i];
237 
238 		if (!ubi)
239 			continue;
240 		count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
241 	}
242 
243 	return count;
244 }
245 
246 /**
247  * ubi_get_device - get UBI device.
248  * @ubi_num: UBI device number
249  *
250  * This function returns UBI device description object for UBI device number
251  * @ubi_num, or %NULL if the device does not exist. This function increases the
252  * device reference count to prevent removal of the device. In other words, the
253  * device cannot be removed if its reference count is not zero.
254  */
255 struct ubi_device *ubi_get_device(int ubi_num)
256 {
257 	struct ubi_device *ubi;
258 
259 	spin_lock(&ubi_devices_lock);
260 	ubi = ubi_devices[ubi_num];
261 	if (ubi) {
262 		ubi_assert(ubi->ref_count >= 0);
263 		ubi->ref_count += 1;
264 		get_device(&ubi->dev);
265 	}
266 	spin_unlock(&ubi_devices_lock);
267 
268 	return ubi;
269 }
270 
271 /**
272  * ubi_put_device - drop an UBI device reference.
273  * @ubi: UBI device description object
274  */
275 void ubi_put_device(struct ubi_device *ubi)
276 {
277 	spin_lock(&ubi_devices_lock);
278 	ubi->ref_count -= 1;
279 	put_device(&ubi->dev);
280 	spin_unlock(&ubi_devices_lock);
281 }
282 
283 /**
284  * ubi_get_by_major - get UBI device by character device major number.
285  * @major: major number
286  *
287  * This function is similar to 'ubi_get_device()', but it searches the device
288  * by its major number.
289  */
290 struct ubi_device *ubi_get_by_major(int major)
291 {
292 	int i;
293 	struct ubi_device *ubi;
294 
295 	spin_lock(&ubi_devices_lock);
296 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
297 		ubi = ubi_devices[i];
298 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
299 			ubi_assert(ubi->ref_count >= 0);
300 			ubi->ref_count += 1;
301 			get_device(&ubi->dev);
302 			spin_unlock(&ubi_devices_lock);
303 			return ubi;
304 		}
305 	}
306 	spin_unlock(&ubi_devices_lock);
307 
308 	return NULL;
309 }
310 
311 /**
312  * ubi_major2num - get UBI device number by character device major number.
313  * @major: major number
314  *
315  * This function searches UBI device number object by its major number. If UBI
316  * device was not found, this function returns -ENODEV, otherwise the UBI device
317  * number is returned.
318  */
319 int ubi_major2num(int major)
320 {
321 	int i, ubi_num = -ENODEV;
322 
323 	spin_lock(&ubi_devices_lock);
324 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
325 		struct ubi_device *ubi = ubi_devices[i];
326 
327 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
328 			ubi_num = ubi->ubi_num;
329 			break;
330 		}
331 	}
332 	spin_unlock(&ubi_devices_lock);
333 
334 	return ubi_num;
335 }
336 
337 /* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
338 static ssize_t dev_attribute_show(struct device *dev,
339 				  struct device_attribute *attr, char *buf)
340 {
341 	ssize_t ret;
342 	struct ubi_device *ubi;
343 
344 	/*
345 	 * The below code looks weird, but it actually makes sense. We get the
346 	 * UBI device reference from the contained 'struct ubi_device'. But it
347 	 * is unclear if the device was removed or not yet. Indeed, if the
348 	 * device was removed before we increased its reference count,
349 	 * 'ubi_get_device()' will return -ENODEV and we fail.
350 	 *
351 	 * Remember, 'struct ubi_device' is freed in the release function, so
352 	 * we still can use 'ubi->ubi_num'.
353 	 */
354 	ubi = container_of(dev, struct ubi_device, dev);
355 	ubi = ubi_get_device(ubi->ubi_num);
356 	if (!ubi)
357 		return -ENODEV;
358 
359 	if (attr == &dev_eraseblock_size)
360 		ret = sprintf(buf, "%d\n", ubi->leb_size);
361 	else if (attr == &dev_avail_eraseblocks)
362 		ret = sprintf(buf, "%d\n", ubi->avail_pebs);
363 	else if (attr == &dev_total_eraseblocks)
364 		ret = sprintf(buf, "%d\n", ubi->good_peb_count);
365 	else if (attr == &dev_volumes_count)
366 		ret = sprintf(buf, "%d\n", ubi->vol_count - UBI_INT_VOL_COUNT);
367 	else if (attr == &dev_max_ec)
368 		ret = sprintf(buf, "%d\n", ubi->max_ec);
369 	else if (attr == &dev_reserved_for_bad)
370 		ret = sprintf(buf, "%d\n", ubi->beb_rsvd_pebs);
371 	else if (attr == &dev_bad_peb_count)
372 		ret = sprintf(buf, "%d\n", ubi->bad_peb_count);
373 	else if (attr == &dev_max_vol_count)
374 		ret = sprintf(buf, "%d\n", ubi->vtbl_slots);
375 	else if (attr == &dev_min_io_size)
376 		ret = sprintf(buf, "%d\n", ubi->min_io_size);
377 	else if (attr == &dev_bgt_enabled)
378 		ret = sprintf(buf, "%d\n", ubi->thread_enabled);
379 	else if (attr == &dev_mtd_num)
380 		ret = sprintf(buf, "%d\n", ubi->mtd->index);
381 	else
382 		ret = -EINVAL;
383 
384 	ubi_put_device(ubi);
385 	return ret;
386 }
387 
388 static void dev_release(struct device *dev)
389 {
390 	struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);
391 
392 	kfree(ubi);
393 }
394 
395 /**
396  * ubi_sysfs_init - initialize sysfs for an UBI device.
397  * @ubi: UBI device description object
398  * @ref: set to %1 on exit in case of failure if a reference to @ubi->dev was
399  *       taken
400  *
401  * This function returns zero in case of success and a negative error code in
402  * case of failure.
403  */
404 static int ubi_sysfs_init(struct ubi_device *ubi, int *ref)
405 {
406 	int err;
407 
408 	ubi->dev.release = dev_release;
409 	ubi->dev.devt = ubi->cdev.dev;
410 	ubi->dev.class = ubi_class;
411 	dev_set_name(&ubi->dev, UBI_NAME_STR"%d", ubi->ubi_num);
412 	err = device_register(&ubi->dev);
413 	if (err)
414 		return err;
415 
416 	*ref = 1;
417 	err = device_create_file(&ubi->dev, &dev_eraseblock_size);
418 	if (err)
419 		return err;
420 	err = device_create_file(&ubi->dev, &dev_avail_eraseblocks);
421 	if (err)
422 		return err;
423 	err = device_create_file(&ubi->dev, &dev_total_eraseblocks);
424 	if (err)
425 		return err;
426 	err = device_create_file(&ubi->dev, &dev_volumes_count);
427 	if (err)
428 		return err;
429 	err = device_create_file(&ubi->dev, &dev_max_ec);
430 	if (err)
431 		return err;
432 	err = device_create_file(&ubi->dev, &dev_reserved_for_bad);
433 	if (err)
434 		return err;
435 	err = device_create_file(&ubi->dev, &dev_bad_peb_count);
436 	if (err)
437 		return err;
438 	err = device_create_file(&ubi->dev, &dev_max_vol_count);
439 	if (err)
440 		return err;
441 	err = device_create_file(&ubi->dev, &dev_min_io_size);
442 	if (err)
443 		return err;
444 	err = device_create_file(&ubi->dev, &dev_bgt_enabled);
445 	if (err)
446 		return err;
447 	err = device_create_file(&ubi->dev, &dev_mtd_num);
448 	return err;
449 }
450 
451 /**
452  * ubi_sysfs_close - close sysfs for an UBI device.
453  * @ubi: UBI device description object
454  */
455 static void ubi_sysfs_close(struct ubi_device *ubi)
456 {
457 	device_remove_file(&ubi->dev, &dev_mtd_num);
458 	device_remove_file(&ubi->dev, &dev_bgt_enabled);
459 	device_remove_file(&ubi->dev, &dev_min_io_size);
460 	device_remove_file(&ubi->dev, &dev_max_vol_count);
461 	device_remove_file(&ubi->dev, &dev_bad_peb_count);
462 	device_remove_file(&ubi->dev, &dev_reserved_for_bad);
463 	device_remove_file(&ubi->dev, &dev_max_ec);
464 	device_remove_file(&ubi->dev, &dev_volumes_count);
465 	device_remove_file(&ubi->dev, &dev_total_eraseblocks);
466 	device_remove_file(&ubi->dev, &dev_avail_eraseblocks);
467 	device_remove_file(&ubi->dev, &dev_eraseblock_size);
468 	device_unregister(&ubi->dev);
469 }
470 
471 /**
472  * kill_volumes - destroy all user volumes.
473  * @ubi: UBI device description object
474  */
475 static void kill_volumes(struct ubi_device *ubi)
476 {
477 	int i;
478 
479 	for (i = 0; i < ubi->vtbl_slots; i++)
480 		if (ubi->volumes[i])
481 			ubi_free_volume(ubi, ubi->volumes[i]);
482 }
483 
484 /**
485  * uif_init - initialize user interfaces for an UBI device.
486  * @ubi: UBI device description object
487  * @ref: set to %1 on exit in case of failure if a reference to @ubi->dev was
488  *       taken, otherwise set to %0
489  *
490  * This function initializes various user interfaces for an UBI device. If the
491  * initialization fails at an early stage, this function frees all the
492  * resources it allocated, returns an error, and @ref is set to %0. However,
493  * if the initialization fails after the UBI device was registered in the
494  * driver core subsystem, this function takes a reference to @ubi->dev, because
495  * otherwise the release function ('dev_release()') would free whole @ubi
496  * object. The @ref argument is set to %1 in this case. The caller has to put
497  * this reference.
498  *
499  * This function returns zero in case of success and a negative error code in
500  * case of failure.
501  */
502 static int uif_init(struct ubi_device *ubi, int *ref)
503 {
504 	int i, err;
505 	dev_t dev;
506 
507 	*ref = 0;
508 	sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);
509 
510 	/*
511 	 * Major numbers for the UBI character devices are allocated
512 	 * dynamically. Major numbers of volume character devices are
513 	 * equivalent to ones of the corresponding UBI character device. Minor
514 	 * numbers of UBI character devices are 0, while minor numbers of
515 	 * volume character devices start from 1. Thus, we allocate one major
516 	 * number and ubi->vtbl_slots + 1 minor numbers.
517 	 */
518 	err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
519 	if (err) {
520 		ubi_err("cannot register UBI character devices");
521 		return err;
522 	}
523 
524 	ubi_assert(MINOR(dev) == 0);
525 	cdev_init(&ubi->cdev, &ubi_cdev_operations);
526 	dbg_gen("%s major is %u", ubi->ubi_name, MAJOR(dev));
527 	ubi->cdev.owner = THIS_MODULE;
528 
529 	err = cdev_add(&ubi->cdev, dev, 1);
530 	if (err) {
531 		ubi_err("cannot add character device");
532 		goto out_unreg;
533 	}
534 
535 	err = ubi_sysfs_init(ubi, ref);
536 	if (err)
537 		goto out_sysfs;
538 
539 	for (i = 0; i < ubi->vtbl_slots; i++)
540 		if (ubi->volumes[i]) {
541 			err = ubi_add_volume(ubi, ubi->volumes[i]);
542 			if (err) {
543 				ubi_err("cannot add volume %d", i);
544 				goto out_volumes;
545 			}
546 		}
547 
548 	return 0;
549 
550 out_volumes:
551 	kill_volumes(ubi);
552 out_sysfs:
553 	if (*ref)
554 		get_device(&ubi->dev);
555 	ubi_sysfs_close(ubi);
556 	cdev_del(&ubi->cdev);
557 out_unreg:
558 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
559 	ubi_err("cannot initialize UBI %s, error %d", ubi->ubi_name, err);
560 	return err;
561 }
562 
563 /**
564  * uif_close - close user interfaces for an UBI device.
565  * @ubi: UBI device description object
566  *
567  * Note, since this function un-registers UBI volume device objects (@vol->dev),
568  * the memory allocated voe the volumes is freed as well (in the release
569  * function).
570  */
571 static void uif_close(struct ubi_device *ubi)
572 {
573 	kill_volumes(ubi);
574 	ubi_sysfs_close(ubi);
575 	cdev_del(&ubi->cdev);
576 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
577 }
578 
579 /**
580  * ubi_free_internal_volumes - free internal volumes.
581  * @ubi: UBI device description object
582  */
583 void ubi_free_internal_volumes(struct ubi_device *ubi)
584 {
585 	int i;
586 
587 	for (i = ubi->vtbl_slots;
588 	     i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
589 		kfree(ubi->volumes[i]->eba_tbl);
590 		kfree(ubi->volumes[i]);
591 	}
592 }
593 
594 static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
595 {
596 	int limit, device_pebs;
597 	uint64_t device_size;
598 
599 	if (!max_beb_per1024)
600 		return 0;
601 
602 	/*
603 	 * Here we are using size of the entire flash chip and
604 	 * not just the MTD partition size because the maximum
605 	 * number of bad eraseblocks is a percentage of the
606 	 * whole device and bad eraseblocks are not fairly
607 	 * distributed over the flash chip. So the worst case
608 	 * is that all the bad eraseblocks of the chip are in
609 	 * the MTD partition we are attaching (ubi->mtd).
610 	 */
611 	device_size = mtd_get_device_size(ubi->mtd);
612 	device_pebs = mtd_div_by_eb(device_size, ubi->mtd);
613 	limit = mult_frac(device_pebs, max_beb_per1024, 1024);
614 
615 	/* Round it up */
616 	if (mult_frac(limit, 1024, max_beb_per1024) < device_pebs)
617 		limit += 1;
618 
619 	return limit;
620 }
621 
622 /**
623  * io_init - initialize I/O sub-system for a given UBI device.
624  * @ubi: UBI device description object
625  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
626  *
627  * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
628  * assumed:
629  *   o EC header is always at offset zero - this cannot be changed;
630  *   o VID header starts just after the EC header at the closest address
631  *     aligned to @io->hdrs_min_io_size;
632  *   o data starts just after the VID header at the closest address aligned to
633  *     @io->min_io_size
634  *
635  * This function returns zero in case of success and a negative error code in
636  * case of failure.
637  */
638 static int io_init(struct ubi_device *ubi, int max_beb_per1024)
639 {
640 	dbg_gen("sizeof(struct ubi_ainf_peb) %zu", sizeof(struct ubi_ainf_peb));
641 	dbg_gen("sizeof(struct ubi_wl_entry) %zu", sizeof(struct ubi_wl_entry));
642 
643 	if (ubi->mtd->numeraseregions != 0) {
644 		/*
645 		 * Some flashes have several erase regions. Different regions
646 		 * may have different eraseblock size and other
647 		 * characteristics. It looks like mostly multi-region flashes
648 		 * have one "main" region and one or more small regions to
649 		 * store boot loader code or boot parameters or whatever. I
650 		 * guess we should just pick the largest region. But this is
651 		 * not implemented.
652 		 */
653 		ubi_err("multiple regions, not implemented");
654 		return -EINVAL;
655 	}
656 
657 	if (ubi->vid_hdr_offset < 0)
658 		return -EINVAL;
659 
660 	/*
661 	 * Note, in this implementation we support MTD devices with 0x7FFFFFFF
662 	 * physical eraseblocks maximum.
663 	 */
664 
665 	ubi->peb_size   = ubi->mtd->erasesize;
666 	ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
667 	ubi->flash_size = ubi->mtd->size;
668 
669 	if (mtd_can_have_bb(ubi->mtd)) {
670 		ubi->bad_allowed = 1;
671 		ubi->bad_peb_limit = get_bad_peb_limit(ubi, max_beb_per1024);
672 	}
673 
674 	if (ubi->mtd->type == MTD_NORFLASH) {
675 		ubi_assert(ubi->mtd->writesize == 1);
676 		ubi->nor_flash = 1;
677 	}
678 
679 	ubi->min_io_size = ubi->mtd->writesize;
680 	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
681 
682 	/*
683 	 * Make sure minimal I/O unit is power of 2. Note, there is no
684 	 * fundamental reason for this assumption. It is just an optimization
685 	 * which allows us to avoid costly division operations.
686 	 */
687 	if (!is_power_of_2(ubi->min_io_size)) {
688 		ubi_err("min. I/O unit (%d) is not power of 2",
689 			ubi->min_io_size);
690 		return -EINVAL;
691 	}
692 
693 	ubi_assert(ubi->hdrs_min_io_size > 0);
694 	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
695 	ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
696 
697 	ubi->max_write_size = ubi->mtd->writebufsize;
698 	/*
699 	 * Maximum write size has to be greater or equivalent to min. I/O
700 	 * size, and be multiple of min. I/O size.
701 	 */
702 	if (ubi->max_write_size < ubi->min_io_size ||
703 	    ubi->max_write_size % ubi->min_io_size ||
704 	    !is_power_of_2(ubi->max_write_size)) {
705 		ubi_err("bad write buffer size %d for %d min. I/O unit",
706 			ubi->max_write_size, ubi->min_io_size);
707 		return -EINVAL;
708 	}
709 
710 	/* Calculate default aligned sizes of EC and VID headers */
711 	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
712 	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
713 
714 	dbg_gen("min_io_size      %d", ubi->min_io_size);
715 	dbg_gen("max_write_size   %d", ubi->max_write_size);
716 	dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
717 	dbg_gen("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
718 	dbg_gen("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
719 
720 	if (ubi->vid_hdr_offset == 0)
721 		/* Default offset */
722 		ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
723 				      ubi->ec_hdr_alsize;
724 	else {
725 		ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
726 						~(ubi->hdrs_min_io_size - 1);
727 		ubi->vid_hdr_shift = ubi->vid_hdr_offset -
728 						ubi->vid_hdr_aloffset;
729 	}
730 
731 	/* Similar for the data offset */
732 	ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
733 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
734 
735 	dbg_gen("vid_hdr_offset   %d", ubi->vid_hdr_offset);
736 	dbg_gen("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
737 	dbg_gen("vid_hdr_shift    %d", ubi->vid_hdr_shift);
738 	dbg_gen("leb_start        %d", ubi->leb_start);
739 
740 	/* The shift must be aligned to 32-bit boundary */
741 	if (ubi->vid_hdr_shift % 4) {
742 		ubi_err("unaligned VID header shift %d",
743 			ubi->vid_hdr_shift);
744 		return -EINVAL;
745 	}
746 
747 	/* Check sanity */
748 	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
749 	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
750 	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
751 	    ubi->leb_start & (ubi->min_io_size - 1)) {
752 		ubi_err("bad VID header (%d) or data offsets (%d)",
753 			ubi->vid_hdr_offset, ubi->leb_start);
754 		return -EINVAL;
755 	}
756 
757 	/*
758 	 * Set maximum amount of physical erroneous eraseblocks to be 10%.
759 	 * Erroneous PEB are those which have read errors.
760 	 */
761 	ubi->max_erroneous = ubi->peb_count / 10;
762 	if (ubi->max_erroneous < 16)
763 		ubi->max_erroneous = 16;
764 	dbg_gen("max_erroneous    %d", ubi->max_erroneous);
765 
766 	/*
767 	 * It may happen that EC and VID headers are situated in one minimal
768 	 * I/O unit. In this case we can only accept this UBI image in
769 	 * read-only mode.
770 	 */
771 	if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
772 		ubi_warn("EC and VID headers are in the same minimal I/O unit, switch to read-only mode");
773 		ubi->ro_mode = 1;
774 	}
775 
776 	ubi->leb_size = ubi->peb_size - ubi->leb_start;
777 
778 	if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
779 		ubi_msg("MTD device %d is write-protected, attach in read-only mode",
780 			ubi->mtd->index);
781 		ubi->ro_mode = 1;
782 	}
783 
784 	/*
785 	 * Note, ideally, we have to initialize @ubi->bad_peb_count here. But
786 	 * unfortunately, MTD does not provide this information. We should loop
787 	 * over all physical eraseblocks and invoke mtd->block_is_bad() for
788 	 * each physical eraseblock. So, we leave @ubi->bad_peb_count
789 	 * uninitialized so far.
790 	 */
791 
792 	return 0;
793 }
794 
795 /**
796  * autoresize - re-size the volume which has the "auto-resize" flag set.
797  * @ubi: UBI device description object
798  * @vol_id: ID of the volume to re-size
799  *
800  * This function re-sizes the volume marked by the %UBI_VTBL_AUTORESIZE_FLG in
801  * the volume table to the largest possible size. See comments in ubi-header.h
802  * for more description of the flag. Returns zero in case of success and a
803  * negative error code in case of failure.
804  */
805 static int autoresize(struct ubi_device *ubi, int vol_id)
806 {
807 	struct ubi_volume_desc desc;
808 	struct ubi_volume *vol = ubi->volumes[vol_id];
809 	int err, old_reserved_pebs = vol->reserved_pebs;
810 
811 	if (ubi->ro_mode) {
812 		ubi_warn("skip auto-resize because of R/O mode");
813 		return 0;
814 	}
815 
816 	/*
817 	 * Clear the auto-resize flag in the volume in-memory copy of the
818 	 * volume table, and 'ubi_resize_volume()' will propagate this change
819 	 * to the flash.
820 	 */
821 	ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;
822 
823 	if (ubi->avail_pebs == 0) {
824 		struct ubi_vtbl_record vtbl_rec;
825 
826 		/*
827 		 * No available PEBs to re-size the volume, clear the flag on
828 		 * flash and exit.
829 		 */
830 		vtbl_rec = ubi->vtbl[vol_id];
831 		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
832 		if (err)
833 			ubi_err("cannot clean auto-resize flag for volume %d",
834 				vol_id);
835 	} else {
836 		desc.vol = vol;
837 		err = ubi_resize_volume(&desc,
838 					old_reserved_pebs + ubi->avail_pebs);
839 		if (err)
840 			ubi_err("cannot auto-resize volume %d", vol_id);
841 	}
842 
843 	if (err)
844 		return err;
845 
846 	ubi_msg("volume %d (\"%s\") re-sized from %d to %d LEBs", vol_id,
847 		vol->name, old_reserved_pebs, vol->reserved_pebs);
848 	return 0;
849 }
850 
851 /**
852  * ubi_attach_mtd_dev - attach an MTD device.
853  * @mtd: MTD device description object
854  * @ubi_num: number to assign to the new UBI device
855  * @vid_hdr_offset: VID header offset
856  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
857  *
858  * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
859  * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
860  * which case this function finds a vacant device number and assigns it
861  * automatically. Returns the new UBI device number in case of success and a
862  * negative error code in case of failure.
863  *
864  * Note, the invocations of this function has to be serialized by the
865  * @ubi_devices_mutex.
866  */
867 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
868 		       int vid_hdr_offset, int max_beb_per1024)
869 {
870 	struct ubi_device *ubi;
871 	int i, err, ref = 0;
872 
873 	if (max_beb_per1024 < 0 || max_beb_per1024 > MAX_MTD_UBI_BEB_LIMIT)
874 		return -EINVAL;
875 
876 	if (!max_beb_per1024)
877 		max_beb_per1024 = CONFIG_MTD_UBI_BEB_LIMIT;
878 
879 	/*
880 	 * Check if we already have the same MTD device attached.
881 	 *
882 	 * Note, this function assumes that UBI devices creations and deletions
883 	 * are serialized, so it does not take the &ubi_devices_lock.
884 	 */
885 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
886 		ubi = ubi_devices[i];
887 		if (ubi && mtd->index == ubi->mtd->index) {
888 			ubi_err("mtd%d is already attached to ubi%d",
889 				mtd->index, i);
890 			return -EEXIST;
891 		}
892 	}
893 
894 	/*
895 	 * Make sure this MTD device is not emulated on top of an UBI volume
896 	 * already. Well, generally this recursion works fine, but there are
897 	 * different problems like the UBI module takes a reference to itself
898 	 * by attaching (and thus, opening) the emulated MTD device. This
899 	 * results in inability to unload the module. And in general it makes
900 	 * no sense to attach emulated MTD devices, so we prohibit this.
901 	 */
902 	if (mtd->type == MTD_UBIVOLUME) {
903 		ubi_err("refuse attaching mtd%d - it is already emulated on top of UBI",
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 			ubi_err("only %d UBI devices may be created",
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 			ubi_err("ubi%d already exists", 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 	ubi->mtd = mtd;
934 	ubi->ubi_num = ubi_num;
935 	ubi->vid_hdr_offset = vid_hdr_offset;
936 	ubi->autoresize_vol_id = -1;
937 
938 #ifdef CONFIG_MTD_UBI_FASTMAP
939 	ubi->fm_pool.used = ubi->fm_pool.size = 0;
940 	ubi->fm_wl_pool.used = ubi->fm_wl_pool.size = 0;
941 
942 	/*
943 	 * fm_pool.max_size is 5% of the total number of PEBs but it's also
944 	 * between UBI_FM_MAX_POOL_SIZE and UBI_FM_MIN_POOL_SIZE.
945 	 */
946 	ubi->fm_pool.max_size = min(((int)mtd_div_by_eb(ubi->mtd->size,
947 		ubi->mtd) / 100) * 5, UBI_FM_MAX_POOL_SIZE);
948 	if (ubi->fm_pool.max_size < UBI_FM_MIN_POOL_SIZE)
949 		ubi->fm_pool.max_size = UBI_FM_MIN_POOL_SIZE;
950 
951 	ubi->fm_wl_pool.max_size = UBI_FM_WL_POOL_SIZE;
952 	ubi->fm_disabled = !fm_autoconvert;
953 
954 	if (!ubi->fm_disabled && (int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd)
955 	    <= UBI_FM_MAX_START) {
956 		ubi_err("More than %i PEBs are needed for fastmap, sorry.",
957 			UBI_FM_MAX_START);
958 		ubi->fm_disabled = 1;
959 	}
960 
961 	ubi_msg("default fastmap pool size: %d", ubi->fm_pool.max_size);
962 	ubi_msg("default fastmap WL pool size: %d", ubi->fm_wl_pool.max_size);
963 #else
964 	ubi->fm_disabled = 1;
965 #endif
966 	mutex_init(&ubi->buf_mutex);
967 	mutex_init(&ubi->ckvol_mutex);
968 	mutex_init(&ubi->device_mutex);
969 	spin_lock_init(&ubi->volumes_lock);
970 	mutex_init(&ubi->fm_mutex);
971 	init_rwsem(&ubi->fm_sem);
972 
973 	ubi_msg("attaching mtd%d to ubi%d", mtd->index, ubi_num);
974 
975 	err = io_init(ubi, max_beb_per1024);
976 	if (err)
977 		goto out_free;
978 
979 	err = -ENOMEM;
980 	ubi->peb_buf = vmalloc(ubi->peb_size);
981 	if (!ubi->peb_buf)
982 		goto out_free;
983 
984 #ifdef CONFIG_MTD_UBI_FASTMAP
985 	ubi->fm_size = ubi_calc_fm_size(ubi);
986 	ubi->fm_buf = vzalloc(ubi->fm_size);
987 	if (!ubi->fm_buf)
988 		goto out_free;
989 #endif
990 	err = ubi_attach(ubi, 0);
991 	if (err) {
992 		ubi_err("failed to attach mtd%d, error %d", mtd->index, err);
993 		goto out_free;
994 	}
995 
996 	if (ubi->autoresize_vol_id != -1) {
997 		err = autoresize(ubi, ubi->autoresize_vol_id);
998 		if (err)
999 			goto out_detach;
1000 	}
1001 
1002 	err = uif_init(ubi, &ref);
1003 	if (err)
1004 		goto out_detach;
1005 
1006 	err = ubi_debugfs_init_dev(ubi);
1007 	if (err)
1008 		goto out_uif;
1009 
1010 	ubi->bgt_thread = kthread_create(ubi_thread, ubi, "%s", ubi->bgt_name);
1011 	if (IS_ERR(ubi->bgt_thread)) {
1012 		err = PTR_ERR(ubi->bgt_thread);
1013 		ubi_err("cannot spawn \"%s\", error %d", ubi->bgt_name,
1014 			err);
1015 		goto out_debugfs;
1016 	}
1017 
1018 	ubi_msg("attached mtd%d (name \"%s\", size %llu MiB) to ubi%d",
1019 		mtd->index, mtd->name, ubi->flash_size >> 20, ubi_num);
1020 	ubi_msg("PEB size: %d bytes (%d KiB), LEB size: %d bytes",
1021 		ubi->peb_size, ubi->peb_size >> 10, ubi->leb_size);
1022 	ubi_msg("min./max. I/O unit sizes: %d/%d, sub-page size %d",
1023 		ubi->min_io_size, ubi->max_write_size, ubi->hdrs_min_io_size);
1024 	ubi_msg("VID header offset: %d (aligned %d), data offset: %d",
1025 		ubi->vid_hdr_offset, ubi->vid_hdr_aloffset, ubi->leb_start);
1026 	ubi_msg("good PEBs: %d, bad PEBs: %d, corrupted PEBs: %d",
1027 		ubi->good_peb_count, ubi->bad_peb_count, ubi->corr_peb_count);
1028 	ubi_msg("user volume: %d, internal volumes: %d, max. volumes count: %d",
1029 		ubi->vol_count - UBI_INT_VOL_COUNT, UBI_INT_VOL_COUNT,
1030 		ubi->vtbl_slots);
1031 	ubi_msg("max/mean erase counter: %d/%d, WL threshold: %d, image sequence number: %u",
1032 		ubi->max_ec, ubi->mean_ec, CONFIG_MTD_UBI_WL_THRESHOLD,
1033 		ubi->image_seq);
1034 	ubi_msg("available PEBs: %d, total reserved PEBs: %d, PEBs reserved for bad PEB handling: %d",
1035 		ubi->avail_pebs, ubi->rsvd_pebs, ubi->beb_rsvd_pebs);
1036 
1037 	/*
1038 	 * The below lock makes sure we do not race with 'ubi_thread()' which
1039 	 * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
1040 	 */
1041 	spin_lock(&ubi->wl_lock);
1042 	ubi->thread_enabled = 1;
1043 	wake_up_process(ubi->bgt_thread);
1044 	spin_unlock(&ubi->wl_lock);
1045 
1046 	ubi_devices[ubi_num] = ubi;
1047 	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
1048 	return ubi_num;
1049 
1050 out_debugfs:
1051 	ubi_debugfs_exit_dev(ubi);
1052 out_uif:
1053 	get_device(&ubi->dev);
1054 	ubi_assert(ref);
1055 	uif_close(ubi);
1056 out_detach:
1057 	ubi_wl_close(ubi);
1058 	ubi_free_internal_volumes(ubi);
1059 	vfree(ubi->vtbl);
1060 out_free:
1061 	vfree(ubi->peb_buf);
1062 	vfree(ubi->fm_buf);
1063 	if (ref)
1064 		put_device(&ubi->dev);
1065 	else
1066 		kfree(ubi);
1067 	return err;
1068 }
1069 
1070 /**
1071  * ubi_detach_mtd_dev - detach an MTD device.
1072  * @ubi_num: UBI device number to detach from
1073  * @anyway: detach MTD even if device reference count is not zero
1074  *
1075  * This function destroys an UBI device number @ubi_num and detaches the
1076  * underlying MTD device. Returns zero in case of success and %-EBUSY if the
1077  * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
1078  * exist.
1079  *
1080  * Note, the invocations of this function has to be serialized by the
1081  * @ubi_devices_mutex.
1082  */
1083 int ubi_detach_mtd_dev(int ubi_num, int anyway)
1084 {
1085 	struct ubi_device *ubi;
1086 
1087 	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
1088 		return -EINVAL;
1089 
1090 	ubi = ubi_get_device(ubi_num);
1091 	if (!ubi)
1092 		return -EINVAL;
1093 
1094 	spin_lock(&ubi_devices_lock);
1095 	put_device(&ubi->dev);
1096 	ubi->ref_count -= 1;
1097 	if (ubi->ref_count) {
1098 		if (!anyway) {
1099 			spin_unlock(&ubi_devices_lock);
1100 			return -EBUSY;
1101 		}
1102 		/* This may only happen if there is a bug */
1103 		ubi_err("%s reference count %d, destroy anyway",
1104 			ubi->ubi_name, ubi->ref_count);
1105 	}
1106 	ubi_devices[ubi_num] = NULL;
1107 	spin_unlock(&ubi_devices_lock);
1108 
1109 	ubi_assert(ubi_num == ubi->ubi_num);
1110 	ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
1111 	ubi_msg("detaching mtd%d from ubi%d", ubi->mtd->index, ubi_num);
1112 #ifdef CONFIG_MTD_UBI_FASTMAP
1113 	/* If we don't write a new fastmap at detach time we lose all
1114 	 * EC updates that have been made since the last written fastmap. */
1115 	ubi_update_fastmap(ubi);
1116 #endif
1117 	/*
1118 	 * Before freeing anything, we have to stop the background thread to
1119 	 * prevent it from doing anything on this device while we are freeing.
1120 	 */
1121 	if (ubi->bgt_thread)
1122 		kthread_stop(ubi->bgt_thread);
1123 
1124 	/*
1125 	 * Get a reference to the device in order to prevent 'dev_release()'
1126 	 * from freeing the @ubi object.
1127 	 */
1128 	get_device(&ubi->dev);
1129 
1130 	ubi_debugfs_exit_dev(ubi);
1131 	uif_close(ubi);
1132 
1133 	ubi_wl_close(ubi);
1134 	ubi_free_internal_volumes(ubi);
1135 	vfree(ubi->vtbl);
1136 	put_mtd_device(ubi->mtd);
1137 	vfree(ubi->peb_buf);
1138 	vfree(ubi->fm_buf);
1139 	ubi_msg("mtd%d is detached from ubi%d", ubi->mtd->index, ubi->ubi_num);
1140 	put_device(&ubi->dev);
1141 	return 0;
1142 }
1143 
1144 /**
1145  * open_mtd_by_chdev - open an MTD device by its character device node path.
1146  * @mtd_dev: MTD character device node path
1147  *
1148  * This helper function opens an MTD device by its character node device path.
1149  * Returns MTD device description object in case of success and a negative
1150  * error code in case of failure.
1151  */
1152 static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
1153 {
1154 	int err, major, minor, mode;
1155 	struct path path;
1156 
1157 	/* Probably this is an MTD character device node path */
1158 	err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
1159 	if (err)
1160 		return ERR_PTR(err);
1161 
1162 	/* MTD device number is defined by the major / minor numbers */
1163 	major = imajor(path.dentry->d_inode);
1164 	minor = iminor(path.dentry->d_inode);
1165 	mode = path.dentry->d_inode->i_mode;
1166 	path_put(&path);
1167 	if (major != MTD_CHAR_MAJOR || !S_ISCHR(mode))
1168 		return ERR_PTR(-EINVAL);
1169 
1170 	if (minor & 1)
1171 		/*
1172 		 * Just do not think the "/dev/mtdrX" devices support is need,
1173 		 * so do not support them to avoid doing extra work.
1174 		 */
1175 		return ERR_PTR(-EINVAL);
1176 
1177 	return get_mtd_device(NULL, minor / 2);
1178 }
1179 
1180 /**
1181  * open_mtd_device - open MTD device by name, character device path, or number.
1182  * @mtd_dev: name, character device node path, or MTD device device number
1183  *
1184  * This function tries to open and MTD device described by @mtd_dev string,
1185  * which is first treated as ASCII MTD device number, and if it is not true, it
1186  * is treated as MTD device name, and if that is also not true, it is treated
1187  * as MTD character device node path. Returns MTD device description object in
1188  * case of success and a negative error code in case of failure.
1189  */
1190 static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
1191 {
1192 	struct mtd_info *mtd;
1193 	int mtd_num;
1194 	char *endp;
1195 
1196 	mtd_num = simple_strtoul(mtd_dev, &endp, 0);
1197 	if (*endp != '\0' || mtd_dev == endp) {
1198 		/*
1199 		 * This does not look like an ASCII integer, probably this is
1200 		 * MTD device name.
1201 		 */
1202 		mtd = get_mtd_device_nm(mtd_dev);
1203 		if (IS_ERR(mtd) && PTR_ERR(mtd) == -ENODEV)
1204 			/* Probably this is an MTD character device node path */
1205 			mtd = open_mtd_by_chdev(mtd_dev);
1206 	} else
1207 		mtd = get_mtd_device(NULL, mtd_num);
1208 
1209 	return mtd;
1210 }
1211 
1212 static int __init ubi_init(void)
1213 {
1214 	int err, i, k;
1215 
1216 	/* Ensure that EC and VID headers have correct size */
1217 	BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
1218 	BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);
1219 
1220 	if (mtd_devs > UBI_MAX_DEVICES) {
1221 		ubi_err("too many MTD devices, maximum is %d", UBI_MAX_DEVICES);
1222 		return -EINVAL;
1223 	}
1224 
1225 	/* Create base sysfs directory and sysfs files */
1226 	ubi_class = class_create(THIS_MODULE, UBI_NAME_STR);
1227 	if (IS_ERR(ubi_class)) {
1228 		err = PTR_ERR(ubi_class);
1229 		ubi_err("cannot create UBI class");
1230 		goto out;
1231 	}
1232 
1233 	err = class_create_file(ubi_class, &ubi_version);
1234 	if (err) {
1235 		ubi_err("cannot create sysfs file");
1236 		goto out_class;
1237 	}
1238 
1239 	err = misc_register(&ubi_ctrl_cdev);
1240 	if (err) {
1241 		ubi_err("cannot register device");
1242 		goto out_version;
1243 	}
1244 
1245 	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
1246 					      sizeof(struct ubi_wl_entry),
1247 					      0, 0, NULL);
1248 	if (!ubi_wl_entry_slab) {
1249 		err = -ENOMEM;
1250 		goto out_dev_unreg;
1251 	}
1252 
1253 	err = ubi_debugfs_init();
1254 	if (err)
1255 		goto out_slab;
1256 
1257 
1258 	/* Attach MTD devices */
1259 	for (i = 0; i < mtd_devs; i++) {
1260 		struct mtd_dev_param *p = &mtd_dev_param[i];
1261 		struct mtd_info *mtd;
1262 
1263 		cond_resched();
1264 
1265 		mtd = open_mtd_device(p->name);
1266 		if (IS_ERR(mtd)) {
1267 			err = PTR_ERR(mtd);
1268 			ubi_err("cannot open mtd %s, error %d", p->name, err);
1269 			/* See comment below re-ubi_is_module(). */
1270 			if (ubi_is_module())
1271 				goto out_detach;
1272 			continue;
1273 		}
1274 
1275 		mutex_lock(&ubi_devices_mutex);
1276 		err = ubi_attach_mtd_dev(mtd, p->ubi_num,
1277 					 p->vid_hdr_offs, p->max_beb_per1024);
1278 		mutex_unlock(&ubi_devices_mutex);
1279 		if (err < 0) {
1280 			ubi_err("cannot attach mtd%d", mtd->index);
1281 			put_mtd_device(mtd);
1282 
1283 			/*
1284 			 * Originally UBI stopped initializing on any error.
1285 			 * However, later on it was found out that this
1286 			 * behavior is not very good when UBI is compiled into
1287 			 * the kernel and the MTD devices to attach are passed
1288 			 * through the command line. Indeed, UBI failure
1289 			 * stopped whole boot sequence.
1290 			 *
1291 			 * To fix this, we changed the behavior for the
1292 			 * non-module case, but preserved the old behavior for
1293 			 * the module case, just for compatibility. This is a
1294 			 * little inconsistent, though.
1295 			 */
1296 			if (ubi_is_module())
1297 				goto out_detach;
1298 		}
1299 	}
1300 
1301 	err = ubiblock_init();
1302 	if (err) {
1303 		ubi_err("block: cannot initialize, error %d", err);
1304 
1305 		/* See comment above re-ubi_is_module(). */
1306 		if (ubi_is_module())
1307 			goto out_detach;
1308 	}
1309 
1310 	return 0;
1311 
1312 out_detach:
1313 	for (k = 0; k < i; k++)
1314 		if (ubi_devices[k]) {
1315 			mutex_lock(&ubi_devices_mutex);
1316 			ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
1317 			mutex_unlock(&ubi_devices_mutex);
1318 		}
1319 	ubi_debugfs_exit();
1320 out_slab:
1321 	kmem_cache_destroy(ubi_wl_entry_slab);
1322 out_dev_unreg:
1323 	misc_deregister(&ubi_ctrl_cdev);
1324 out_version:
1325 	class_remove_file(ubi_class, &ubi_version);
1326 out_class:
1327 	class_destroy(ubi_class);
1328 out:
1329 	ubi_err("cannot initialize UBI, error %d", err);
1330 	return err;
1331 }
1332 late_initcall(ubi_init);
1333 
1334 static void __exit ubi_exit(void)
1335 {
1336 	int i;
1337 
1338 	ubiblock_exit();
1339 
1340 	for (i = 0; i < UBI_MAX_DEVICES; i++)
1341 		if (ubi_devices[i]) {
1342 			mutex_lock(&ubi_devices_mutex);
1343 			ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
1344 			mutex_unlock(&ubi_devices_mutex);
1345 		}
1346 	ubi_debugfs_exit();
1347 	kmem_cache_destroy(ubi_wl_entry_slab);
1348 	misc_deregister(&ubi_ctrl_cdev);
1349 	class_remove_file(ubi_class, &ubi_version);
1350 	class_destroy(ubi_class);
1351 }
1352 module_exit(ubi_exit);
1353 
1354 /**
1355  * bytes_str_to_int - convert a number of bytes string into an integer.
1356  * @str: the string to convert
1357  *
1358  * This function returns positive resulting integer in case of success and a
1359  * negative error code in case of failure.
1360  */
1361 static int __init bytes_str_to_int(const char *str)
1362 {
1363 	char *endp;
1364 	unsigned long result;
1365 
1366 	result = simple_strtoul(str, &endp, 0);
1367 	if (str == endp || result >= INT_MAX) {
1368 		ubi_err("incorrect bytes count: \"%s\"\n", str);
1369 		return -EINVAL;
1370 	}
1371 
1372 	switch (*endp) {
1373 	case 'G':
1374 		result *= 1024;
1375 	case 'M':
1376 		result *= 1024;
1377 	case 'K':
1378 		result *= 1024;
1379 		if (endp[1] == 'i' && endp[2] == 'B')
1380 			endp += 2;
1381 	case '\0':
1382 		break;
1383 	default:
1384 		ubi_err("incorrect bytes count: \"%s\"\n", str);
1385 		return -EINVAL;
1386 	}
1387 
1388 	return result;
1389 }
1390 
1391 /**
1392  * ubi_mtd_param_parse - parse the 'mtd=' UBI parameter.
1393  * @val: the parameter value to parse
1394  * @kp: not used
1395  *
1396  * This function returns zero in case of success and a negative error code in
1397  * case of error.
1398  */
1399 static int __init ubi_mtd_param_parse(const char *val, struct kernel_param *kp)
1400 {
1401 	int i, len;
1402 	struct mtd_dev_param *p;
1403 	char buf[MTD_PARAM_LEN_MAX];
1404 	char *pbuf = &buf[0];
1405 	char *tokens[MTD_PARAM_MAX_COUNT], *token;
1406 
1407 	if (!val)
1408 		return -EINVAL;
1409 
1410 	if (mtd_devs == UBI_MAX_DEVICES) {
1411 		ubi_err("too many parameters, max. is %d\n",
1412 			UBI_MAX_DEVICES);
1413 		return -EINVAL;
1414 	}
1415 
1416 	len = strnlen(val, MTD_PARAM_LEN_MAX);
1417 	if (len == MTD_PARAM_LEN_MAX) {
1418 		ubi_err("parameter \"%s\" is too long, max. is %d\n",
1419 			val, MTD_PARAM_LEN_MAX);
1420 		return -EINVAL;
1421 	}
1422 
1423 	if (len == 0) {
1424 		pr_warn("UBI warning: empty 'mtd=' parameter - ignored\n");
1425 		return 0;
1426 	}
1427 
1428 	strcpy(buf, val);
1429 
1430 	/* Get rid of the final newline */
1431 	if (buf[len - 1] == '\n')
1432 		buf[len - 1] = '\0';
1433 
1434 	for (i = 0; i < MTD_PARAM_MAX_COUNT; i++)
1435 		tokens[i] = strsep(&pbuf, ",");
1436 
1437 	if (pbuf) {
1438 		ubi_err("too many arguments at \"%s\"\n", val);
1439 		return -EINVAL;
1440 	}
1441 
1442 	p = &mtd_dev_param[mtd_devs];
1443 	strcpy(&p->name[0], tokens[0]);
1444 
1445 	token = tokens[1];
1446 	if (token) {
1447 		p->vid_hdr_offs = bytes_str_to_int(token);
1448 
1449 		if (p->vid_hdr_offs < 0)
1450 			return p->vid_hdr_offs;
1451 	}
1452 
1453 	token = tokens[2];
1454 	if (token) {
1455 		int err = kstrtoint(token, 10, &p->max_beb_per1024);
1456 
1457 		if (err) {
1458 			ubi_err("bad value for max_beb_per1024 parameter: %s",
1459 				token);
1460 			return -EINVAL;
1461 		}
1462 	}
1463 
1464 	token = tokens[3];
1465 	if (token) {
1466 		int err = kstrtoint(token, 10, &p->ubi_num);
1467 
1468 		if (err) {
1469 			ubi_err("bad value for ubi_num parameter: %s", token);
1470 			return -EINVAL;
1471 		}
1472 	} else
1473 		p->ubi_num = UBI_DEV_NUM_AUTO;
1474 
1475 	mtd_devs += 1;
1476 	return 0;
1477 }
1478 
1479 module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 000);
1480 MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024[,ubi_num]]].\n"
1481 		      "Multiple \"mtd\" parameters may be specified.\n"
1482 		      "MTD devices may be specified by their number, name, or path to the MTD character device node.\n"
1483 		      "Optional \"vid_hdr_offs\" parameter specifies UBI VID header position to be used by UBI. (default value if 0)\n"
1484 		      "Optional \"max_beb_per1024\" parameter specifies the maximum expected bad eraseblock per 1024 eraseblocks. (default value ("
1485 		      __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0)\n"
1486 		      "Optional \"ubi_num\" parameter specifies UBI device number which have to be assigned to the newly created UBI device (assigned automatically by default)\n"
1487 		      "\n"
1488 		      "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
1489 		      "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"
1490 		      "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"
1491 		      "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"
1492 		      "\t(e.g. if the NAND *chipset* has 4096 PEB, 100 will be reserved for this UBI device).");
1493 #ifdef CONFIG_MTD_UBI_FASTMAP
1494 module_param(fm_autoconvert, bool, 0644);
1495 MODULE_PARM_DESC(fm_autoconvert, "Set this parameter to enable fastmap automatically on images without a fastmap.");
1496 #endif
1497 MODULE_VERSION(__stringify(UBI_VERSION));
1498 MODULE_DESCRIPTION("UBI - Unsorted Block Images");
1499 MODULE_AUTHOR("Artem Bityutskiy");
1500 MODULE_LICENSE("GPL");
1501