xref: /openbmc/linux/drivers/mtd/ubi/build.c (revision e23feb16)
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 "ubi.h"
45 
46 /* Maximum length of the 'mtd=' parameter */
47 #define MTD_PARAM_LEN_MAX 64
48 
49 /* Maximum number of comma-separated items in the 'mtd=' parameter */
50 #define MTD_PARAM_MAX_COUNT 4
51 
52 /* Maximum value for the number of bad PEBs per 1024 PEBs */
53 #define MAX_MTD_UBI_BEB_LIMIT 768
54 
55 #ifdef CONFIG_MTD_UBI_MODULE
56 #define ubi_is_module() 1
57 #else
58 #define ubi_is_module() 0
59 #endif
60 
61 /**
62  * struct mtd_dev_param - MTD device parameter description data structure.
63  * @name: MTD character device node path, MTD device name, or MTD device number
64  *        string
65  * @vid_hdr_offs: VID header offset
66  * @max_beb_per1024: maximum expected number of bad PEBs per 1024 PEBs
67  */
68 struct mtd_dev_param {
69 	char name[MTD_PARAM_LEN_MAX];
70 	int ubi_num;
71 	int vid_hdr_offs;
72 	int max_beb_per1024;
73 };
74 
75 /* Numbers of elements set in the @mtd_dev_param array */
76 static int __initdata mtd_devs;
77 
78 /* MTD devices specification parameters */
79 static struct mtd_dev_param __initdata mtd_dev_param[UBI_MAX_DEVICES];
80 #ifdef CONFIG_MTD_UBI_FASTMAP
81 /* UBI module parameter to enable fastmap automatically on non-fastmap images */
82 static bool fm_autoconvert;
83 #endif
84 /* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
85 struct class *ubi_class;
86 
87 /* Slab cache for wear-leveling entries */
88 struct kmem_cache *ubi_wl_entry_slab;
89 
90 /* UBI control character device */
91 static struct miscdevice ubi_ctrl_cdev = {
92 	.minor = MISC_DYNAMIC_MINOR,
93 	.name = "ubi_ctrl",
94 	.fops = &ubi_ctrl_cdev_operations,
95 };
96 
97 /* All UBI devices in system */
98 static struct ubi_device *ubi_devices[UBI_MAX_DEVICES];
99 
100 /* Serializes UBI devices creations and removals */
101 DEFINE_MUTEX(ubi_devices_mutex);
102 
103 /* Protects @ubi_devices and @ubi->ref_count */
104 static DEFINE_SPINLOCK(ubi_devices_lock);
105 
106 /* "Show" method for files in '/<sysfs>/class/ubi/' */
107 static ssize_t ubi_version_show(struct class *class,
108 				struct class_attribute *attr, char *buf)
109 {
110 	return sprintf(buf, "%d\n", UBI_VERSION);
111 }
112 
113 /* UBI version attribute ('/<sysfs>/class/ubi/version') */
114 static struct class_attribute ubi_version =
115 	__ATTR(version, S_IRUGO, ubi_version_show, NULL);
116 
117 static ssize_t dev_attribute_show(struct device *dev,
118 				  struct device_attribute *attr, char *buf);
119 
120 /* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
121 static struct device_attribute dev_eraseblock_size =
122 	__ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
123 static struct device_attribute dev_avail_eraseblocks =
124 	__ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
125 static struct device_attribute dev_total_eraseblocks =
126 	__ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
127 static struct device_attribute dev_volumes_count =
128 	__ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
129 static struct device_attribute dev_max_ec =
130 	__ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
131 static struct device_attribute dev_reserved_for_bad =
132 	__ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
133 static struct device_attribute dev_bad_peb_count =
134 	__ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
135 static struct device_attribute dev_max_vol_count =
136 	__ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
137 static struct device_attribute dev_min_io_size =
138 	__ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
139 static struct device_attribute dev_bgt_enabled =
140 	__ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);
141 static struct device_attribute dev_mtd_num =
142 	__ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
143 
144 /**
145  * ubi_volume_notify - send a volume change notification.
146  * @ubi: UBI device description object
147  * @vol: volume description object of the changed volume
148  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
149  *
150  * This is a helper function which notifies all subscribers about a volume
151  * change event (creation, removal, re-sizing, re-naming, updating). Returns
152  * zero in case of success and a negative error code in case of failure.
153  */
154 int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
155 {
156 	struct ubi_notification nt;
157 
158 	ubi_do_get_device_info(ubi, &nt.di);
159 	ubi_do_get_volume_info(ubi, vol, &nt.vi);
160 
161 #ifdef CONFIG_MTD_UBI_FASTMAP
162 	switch (ntype) {
163 	case UBI_VOLUME_ADDED:
164 	case UBI_VOLUME_REMOVED:
165 	case UBI_VOLUME_RESIZED:
166 	case UBI_VOLUME_RENAMED:
167 		if (ubi_update_fastmap(ubi)) {
168 			ubi_err("Unable to update fastmap!");
169 			ubi_ro_mode(ubi);
170 		}
171 	}
172 #endif
173 	return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
174 }
175 
176 /**
177  * ubi_notify_all - send a notification to all volumes.
178  * @ubi: UBI device description object
179  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
180  * @nb: the notifier to call
181  *
182  * This function walks all volumes of UBI device @ubi and sends the @ntype
183  * notification for each volume. If @nb is %NULL, then all registered notifiers
184  * are called, otherwise only the @nb notifier is called. Returns the number of
185  * sent notifications.
186  */
187 int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
188 {
189 	struct ubi_notification nt;
190 	int i, count = 0;
191 
192 	ubi_do_get_device_info(ubi, &nt.di);
193 
194 	mutex_lock(&ubi->device_mutex);
195 	for (i = 0; i < ubi->vtbl_slots; i++) {
196 		/*
197 		 * Since the @ubi->device is locked, and we are not going to
198 		 * change @ubi->volumes, we do not have to lock
199 		 * @ubi->volumes_lock.
200 		 */
201 		if (!ubi->volumes[i])
202 			continue;
203 
204 		ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
205 		if (nb)
206 			nb->notifier_call(nb, ntype, &nt);
207 		else
208 			blocking_notifier_call_chain(&ubi_notifiers, ntype,
209 						     &nt);
210 		count += 1;
211 	}
212 	mutex_unlock(&ubi->device_mutex);
213 
214 	return count;
215 }
216 
217 /**
218  * ubi_enumerate_volumes - send "add" notification for all existing volumes.
219  * @nb: the notifier to call
220  *
221  * This function walks all UBI devices and volumes and sends the
222  * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
223  * registered notifiers are called, otherwise only the @nb notifier is called.
224  * Returns the number of sent notifications.
225  */
226 int ubi_enumerate_volumes(struct notifier_block *nb)
227 {
228 	int i, count = 0;
229 
230 	/*
231 	 * Since the @ubi_devices_mutex is locked, and we are not going to
232 	 * change @ubi_devices, we do not have to lock @ubi_devices_lock.
233 	 */
234 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
235 		struct ubi_device *ubi = ubi_devices[i];
236 
237 		if (!ubi)
238 			continue;
239 		count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
240 	}
241 
242 	return count;
243 }
244 
245 /**
246  * ubi_get_device - get UBI device.
247  * @ubi_num: UBI device number
248  *
249  * This function returns UBI device description object for UBI device number
250  * @ubi_num, or %NULL if the device does not exist. This function increases the
251  * device reference count to prevent removal of the device. In other words, the
252  * device cannot be removed if its reference count is not zero.
253  */
254 struct ubi_device *ubi_get_device(int ubi_num)
255 {
256 	struct ubi_device *ubi;
257 
258 	spin_lock(&ubi_devices_lock);
259 	ubi = ubi_devices[ubi_num];
260 	if (ubi) {
261 		ubi_assert(ubi->ref_count >= 0);
262 		ubi->ref_count += 1;
263 		get_device(&ubi->dev);
264 	}
265 	spin_unlock(&ubi_devices_lock);
266 
267 	return ubi;
268 }
269 
270 /**
271  * ubi_put_device - drop an UBI device reference.
272  * @ubi: UBI device description object
273  */
274 void ubi_put_device(struct ubi_device *ubi)
275 {
276 	spin_lock(&ubi_devices_lock);
277 	ubi->ref_count -= 1;
278 	put_device(&ubi->dev);
279 	spin_unlock(&ubi_devices_lock);
280 }
281 
282 /**
283  * ubi_get_by_major - get UBI device by character device major number.
284  * @major: major number
285  *
286  * This function is similar to 'ubi_get_device()', but it searches the device
287  * by its major number.
288  */
289 struct ubi_device *ubi_get_by_major(int major)
290 {
291 	int i;
292 	struct ubi_device *ubi;
293 
294 	spin_lock(&ubi_devices_lock);
295 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
296 		ubi = ubi_devices[i];
297 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
298 			ubi_assert(ubi->ref_count >= 0);
299 			ubi->ref_count += 1;
300 			get_device(&ubi->dev);
301 			spin_unlock(&ubi_devices_lock);
302 			return ubi;
303 		}
304 	}
305 	spin_unlock(&ubi_devices_lock);
306 
307 	return NULL;
308 }
309 
310 /**
311  * ubi_major2num - get UBI device number by character device major number.
312  * @major: major number
313  *
314  * This function searches UBI device number object by its major number. If UBI
315  * device was not found, this function returns -ENODEV, otherwise the UBI device
316  * number is returned.
317  */
318 int ubi_major2num(int major)
319 {
320 	int i, ubi_num = -ENODEV;
321 
322 	spin_lock(&ubi_devices_lock);
323 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
324 		struct ubi_device *ubi = ubi_devices[i];
325 
326 		if (ubi && MAJOR(ubi->cdev.dev) == major) {
327 			ubi_num = ubi->ubi_num;
328 			break;
329 		}
330 	}
331 	spin_unlock(&ubi_devices_lock);
332 
333 	return ubi_num;
334 }
335 
336 /* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
337 static ssize_t dev_attribute_show(struct device *dev,
338 				  struct device_attribute *attr, char *buf)
339 {
340 	ssize_t ret;
341 	struct ubi_device *ubi;
342 
343 	/*
344 	 * The below code looks weird, but it actually makes sense. We get the
345 	 * UBI device reference from the contained 'struct ubi_device'. But it
346 	 * is unclear if the device was removed or not yet. Indeed, if the
347 	 * device was removed before we increased its reference count,
348 	 * 'ubi_get_device()' will return -ENODEV and we fail.
349 	 *
350 	 * Remember, 'struct ubi_device' is freed in the release function, so
351 	 * we still can use 'ubi->ubi_num'.
352 	 */
353 	ubi = container_of(dev, struct ubi_device, dev);
354 	ubi = ubi_get_device(ubi->ubi_num);
355 	if (!ubi)
356 		return -ENODEV;
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
381 		ret = -EINVAL;
382 
383 	ubi_put_device(ubi);
384 	return ret;
385 }
386 
387 static void dev_release(struct device *dev)
388 {
389 	struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);
390 
391 	kfree(ubi);
392 }
393 
394 /**
395  * ubi_sysfs_init - initialize sysfs for an UBI device.
396  * @ubi: UBI device description object
397  * @ref: set to %1 on exit in case of failure if a reference to @ubi->dev was
398  *       taken
399  *
400  * This function returns zero in case of success and a negative error code in
401  * case of failure.
402  */
403 static int ubi_sysfs_init(struct ubi_device *ubi, int *ref)
404 {
405 	int err;
406 
407 	ubi->dev.release = dev_release;
408 	ubi->dev.devt = ubi->cdev.dev;
409 	ubi->dev.class = ubi_class;
410 	dev_set_name(&ubi->dev, UBI_NAME_STR"%d", ubi->ubi_num);
411 	err = device_register(&ubi->dev);
412 	if (err)
413 		return err;
414 
415 	*ref = 1;
416 	err = device_create_file(&ubi->dev, &dev_eraseblock_size);
417 	if (err)
418 		return err;
419 	err = device_create_file(&ubi->dev, &dev_avail_eraseblocks);
420 	if (err)
421 		return err;
422 	err = device_create_file(&ubi->dev, &dev_total_eraseblocks);
423 	if (err)
424 		return err;
425 	err = device_create_file(&ubi->dev, &dev_volumes_count);
426 	if (err)
427 		return err;
428 	err = device_create_file(&ubi->dev, &dev_max_ec);
429 	if (err)
430 		return err;
431 	err = device_create_file(&ubi->dev, &dev_reserved_for_bad);
432 	if (err)
433 		return err;
434 	err = device_create_file(&ubi->dev, &dev_bad_peb_count);
435 	if (err)
436 		return err;
437 	err = device_create_file(&ubi->dev, &dev_max_vol_count);
438 	if (err)
439 		return err;
440 	err = device_create_file(&ubi->dev, &dev_min_io_size);
441 	if (err)
442 		return err;
443 	err = device_create_file(&ubi->dev, &dev_bgt_enabled);
444 	if (err)
445 		return err;
446 	err = device_create_file(&ubi->dev, &dev_mtd_num);
447 	return err;
448 }
449 
450 /**
451  * ubi_sysfs_close - close sysfs for an UBI device.
452  * @ubi: UBI device description object
453  */
454 static void ubi_sysfs_close(struct ubi_device *ubi)
455 {
456 	device_remove_file(&ubi->dev, &dev_mtd_num);
457 	device_remove_file(&ubi->dev, &dev_bgt_enabled);
458 	device_remove_file(&ubi->dev, &dev_min_io_size);
459 	device_remove_file(&ubi->dev, &dev_max_vol_count);
460 	device_remove_file(&ubi->dev, &dev_bad_peb_count);
461 	device_remove_file(&ubi->dev, &dev_reserved_for_bad);
462 	device_remove_file(&ubi->dev, &dev_max_ec);
463 	device_remove_file(&ubi->dev, &dev_volumes_count);
464 	device_remove_file(&ubi->dev, &dev_total_eraseblocks);
465 	device_remove_file(&ubi->dev, &dev_avail_eraseblocks);
466 	device_remove_file(&ubi->dev, &dev_eraseblock_size);
467 	device_unregister(&ubi->dev);
468 }
469 
470 /**
471  * kill_volumes - destroy all user volumes.
472  * @ubi: UBI device description object
473  */
474 static void kill_volumes(struct ubi_device *ubi)
475 {
476 	int i;
477 
478 	for (i = 0; i < ubi->vtbl_slots; i++)
479 		if (ubi->volumes[i])
480 			ubi_free_volume(ubi, ubi->volumes[i]);
481 }
482 
483 /**
484  * uif_init - initialize user interfaces for an UBI device.
485  * @ubi: UBI device description object
486  * @ref: set to %1 on exit in case of failure if a reference to @ubi->dev was
487  *       taken, otherwise set to %0
488  *
489  * This function initializes various user interfaces for an UBI device. If the
490  * initialization fails at an early stage, this function frees all the
491  * resources it allocated, returns an error, and @ref is set to %0. However,
492  * if the initialization fails after the UBI device was registered in the
493  * driver core subsystem, this function takes a reference to @ubi->dev, because
494  * otherwise the release function ('dev_release()') would free whole @ubi
495  * object. The @ref argument is set to %1 in this case. The caller has to put
496  * this reference.
497  *
498  * This function returns zero in case of success and a negative error code in
499  * case of failure.
500  */
501 static int uif_init(struct ubi_device *ubi, int *ref)
502 {
503 	int i, err;
504 	dev_t dev;
505 
506 	*ref = 0;
507 	sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);
508 
509 	/*
510 	 * Major numbers for the UBI character devices are allocated
511 	 * dynamically. Major numbers of volume character devices are
512 	 * equivalent to ones of the corresponding UBI character device. Minor
513 	 * numbers of UBI character devices are 0, while minor numbers of
514 	 * volume character devices start from 1. Thus, we allocate one major
515 	 * number and ubi->vtbl_slots + 1 minor numbers.
516 	 */
517 	err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
518 	if (err) {
519 		ubi_err("cannot register UBI character devices");
520 		return err;
521 	}
522 
523 	ubi_assert(MINOR(dev) == 0);
524 	cdev_init(&ubi->cdev, &ubi_cdev_operations);
525 	dbg_gen("%s major is %u", ubi->ubi_name, MAJOR(dev));
526 	ubi->cdev.owner = THIS_MODULE;
527 
528 	err = cdev_add(&ubi->cdev, dev, 1);
529 	if (err) {
530 		ubi_err("cannot add character device");
531 		goto out_unreg;
532 	}
533 
534 	err = ubi_sysfs_init(ubi, ref);
535 	if (err)
536 		goto out_sysfs;
537 
538 	for (i = 0; i < ubi->vtbl_slots; i++)
539 		if (ubi->volumes[i]) {
540 			err = ubi_add_volume(ubi, ubi->volumes[i]);
541 			if (err) {
542 				ubi_err("cannot add volume %d", i);
543 				goto out_volumes;
544 			}
545 		}
546 
547 	return 0;
548 
549 out_volumes:
550 	kill_volumes(ubi);
551 out_sysfs:
552 	if (*ref)
553 		get_device(&ubi->dev);
554 	ubi_sysfs_close(ubi);
555 	cdev_del(&ubi->cdev);
556 out_unreg:
557 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
558 	ubi_err("cannot initialize UBI %s, error %d", ubi->ubi_name, err);
559 	return err;
560 }
561 
562 /**
563  * uif_close - close user interfaces for an UBI device.
564  * @ubi: UBI device description object
565  *
566  * Note, since this function un-registers UBI volume device objects (@vol->dev),
567  * the memory allocated voe the volumes is freed as well (in the release
568  * function).
569  */
570 static void uif_close(struct ubi_device *ubi)
571 {
572 	kill_volumes(ubi);
573 	ubi_sysfs_close(ubi);
574 	cdev_del(&ubi->cdev);
575 	unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
576 }
577 
578 /**
579  * ubi_free_internal_volumes - free internal volumes.
580  * @ubi: UBI device description object
581  */
582 void ubi_free_internal_volumes(struct ubi_device *ubi)
583 {
584 	int i;
585 
586 	for (i = ubi->vtbl_slots;
587 	     i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
588 		kfree(ubi->volumes[i]->eba_tbl);
589 		kfree(ubi->volumes[i]);
590 	}
591 }
592 
593 static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
594 {
595 	int limit, device_pebs;
596 	uint64_t device_size;
597 
598 	if (!max_beb_per1024)
599 		return 0;
600 
601 	/*
602 	 * Here we are using size of the entire flash chip and
603 	 * not just the MTD partition size because the maximum
604 	 * number of bad eraseblocks is a percentage of the
605 	 * whole device and bad eraseblocks are not fairly
606 	 * distributed over the flash chip. So the worst case
607 	 * is that all the bad eraseblocks of the chip are in
608 	 * the MTD partition we are attaching (ubi->mtd).
609 	 */
610 	device_size = mtd_get_device_size(ubi->mtd);
611 	device_pebs = mtd_div_by_eb(device_size, ubi->mtd);
612 	limit = mult_frac(device_pebs, max_beb_per1024, 1024);
613 
614 	/* Round it up */
615 	if (mult_frac(limit, 1024, max_beb_per1024) < device_pebs)
616 		limit += 1;
617 
618 	return limit;
619 }
620 
621 /**
622  * io_init - initialize I/O sub-system for a given UBI device.
623  * @ubi: UBI device description object
624  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
625  *
626  * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
627  * assumed:
628  *   o EC header is always at offset zero - this cannot be changed;
629  *   o VID header starts just after the EC header at the closest address
630  *     aligned to @io->hdrs_min_io_size;
631  *   o data starts just after the VID header at the closest address aligned to
632  *     @io->min_io_size
633  *
634  * This function returns zero in case of success and a negative error code in
635  * case of failure.
636  */
637 static int io_init(struct ubi_device *ubi, int max_beb_per1024)
638 {
639 	dbg_gen("sizeof(struct ubi_ainf_peb) %zu", sizeof(struct ubi_ainf_peb));
640 	dbg_gen("sizeof(struct ubi_wl_entry) %zu", sizeof(struct ubi_wl_entry));
641 
642 	if (ubi->mtd->numeraseregions != 0) {
643 		/*
644 		 * Some flashes have several erase regions. Different regions
645 		 * may have different eraseblock size and other
646 		 * characteristics. It looks like mostly multi-region flashes
647 		 * have one "main" region and one or more small regions to
648 		 * store boot loader code or boot parameters or whatever. I
649 		 * guess we should just pick the largest region. But this is
650 		 * not implemented.
651 		 */
652 		ubi_err("multiple regions, not implemented");
653 		return -EINVAL;
654 	}
655 
656 	if (ubi->vid_hdr_offset < 0)
657 		return -EINVAL;
658 
659 	/*
660 	 * Note, in this implementation we support MTD devices with 0x7FFFFFFF
661 	 * physical eraseblocks maximum.
662 	 */
663 
664 	ubi->peb_size   = ubi->mtd->erasesize;
665 	ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
666 	ubi->flash_size = ubi->mtd->size;
667 
668 	if (mtd_can_have_bb(ubi->mtd)) {
669 		ubi->bad_allowed = 1;
670 		ubi->bad_peb_limit = get_bad_peb_limit(ubi, max_beb_per1024);
671 	}
672 
673 	if (ubi->mtd->type == MTD_NORFLASH) {
674 		ubi_assert(ubi->mtd->writesize == 1);
675 		ubi->nor_flash = 1;
676 	}
677 
678 	ubi->min_io_size = ubi->mtd->writesize;
679 	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
680 
681 	/*
682 	 * Make sure minimal I/O unit is power of 2. Note, there is no
683 	 * fundamental reason for this assumption. It is just an optimization
684 	 * which allows us to avoid costly division operations.
685 	 */
686 	if (!is_power_of_2(ubi->min_io_size)) {
687 		ubi_err("min. I/O unit (%d) is not power of 2",
688 			ubi->min_io_size);
689 		return -EINVAL;
690 	}
691 
692 	ubi_assert(ubi->hdrs_min_io_size > 0);
693 	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
694 	ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
695 
696 	ubi->max_write_size = ubi->mtd->writebufsize;
697 	/*
698 	 * Maximum write size has to be greater or equivalent to min. I/O
699 	 * size, and be multiple of min. I/O size.
700 	 */
701 	if (ubi->max_write_size < ubi->min_io_size ||
702 	    ubi->max_write_size % ubi->min_io_size ||
703 	    !is_power_of_2(ubi->max_write_size)) {
704 		ubi_err("bad write buffer size %d for %d min. I/O unit",
705 			ubi->max_write_size, ubi->min_io_size);
706 		return -EINVAL;
707 	}
708 
709 	/* Calculate default aligned sizes of EC and VID headers */
710 	ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
711 	ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
712 
713 	dbg_gen("min_io_size      %d", ubi->min_io_size);
714 	dbg_gen("max_write_size   %d", ubi->max_write_size);
715 	dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
716 	dbg_gen("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
717 	dbg_gen("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
718 
719 	if (ubi->vid_hdr_offset == 0)
720 		/* Default offset */
721 		ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
722 				      ubi->ec_hdr_alsize;
723 	else {
724 		ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
725 						~(ubi->hdrs_min_io_size - 1);
726 		ubi->vid_hdr_shift = ubi->vid_hdr_offset -
727 						ubi->vid_hdr_aloffset;
728 	}
729 
730 	/* Similar for the data offset */
731 	ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
732 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
733 
734 	dbg_gen("vid_hdr_offset   %d", ubi->vid_hdr_offset);
735 	dbg_gen("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
736 	dbg_gen("vid_hdr_shift    %d", ubi->vid_hdr_shift);
737 	dbg_gen("leb_start        %d", ubi->leb_start);
738 
739 	/* The shift must be aligned to 32-bit boundary */
740 	if (ubi->vid_hdr_shift % 4) {
741 		ubi_err("unaligned VID header shift %d",
742 			ubi->vid_hdr_shift);
743 		return -EINVAL;
744 	}
745 
746 	/* Check sanity */
747 	if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
748 	    ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
749 	    ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
750 	    ubi->leb_start & (ubi->min_io_size - 1)) {
751 		ubi_err("bad VID header (%d) or data offsets (%d)",
752 			ubi->vid_hdr_offset, ubi->leb_start);
753 		return -EINVAL;
754 	}
755 
756 	/*
757 	 * Set maximum amount of physical erroneous eraseblocks to be 10%.
758 	 * Erroneous PEB are those which have read errors.
759 	 */
760 	ubi->max_erroneous = ubi->peb_count / 10;
761 	if (ubi->max_erroneous < 16)
762 		ubi->max_erroneous = 16;
763 	dbg_gen("max_erroneous    %d", ubi->max_erroneous);
764 
765 	/*
766 	 * It may happen that EC and VID headers are situated in one minimal
767 	 * I/O unit. In this case we can only accept this UBI image in
768 	 * read-only mode.
769 	 */
770 	if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
771 		ubi_warn("EC and VID headers are in the same minimal I/O unit, switch to read-only mode");
772 		ubi->ro_mode = 1;
773 	}
774 
775 	ubi->leb_size = ubi->peb_size - ubi->leb_start;
776 
777 	if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
778 		ubi_msg("MTD device %d is write-protected, attach in read-only mode",
779 			ubi->mtd->index);
780 		ubi->ro_mode = 1;
781 	}
782 
783 	/*
784 	 * Note, ideally, we have to initialize @ubi->bad_peb_count here. But
785 	 * unfortunately, MTD does not provide this information. We should loop
786 	 * over all physical eraseblocks and invoke mtd->block_is_bad() for
787 	 * each physical eraseblock. So, we leave @ubi->bad_peb_count
788 	 * uninitialized so far.
789 	 */
790 
791 	return 0;
792 }
793 
794 /**
795  * autoresize - re-size the volume which has the "auto-resize" flag set.
796  * @ubi: UBI device description object
797  * @vol_id: ID of the volume to re-size
798  *
799  * This function re-sizes the volume marked by the %UBI_VTBL_AUTORESIZE_FLG in
800  * the volume table to the largest possible size. See comments in ubi-header.h
801  * for more description of the flag. Returns zero in case of success and a
802  * negative error code in case of failure.
803  */
804 static int autoresize(struct ubi_device *ubi, int vol_id)
805 {
806 	struct ubi_volume_desc desc;
807 	struct ubi_volume *vol = ubi->volumes[vol_id];
808 	int err, old_reserved_pebs = vol->reserved_pebs;
809 
810 	if (ubi->ro_mode) {
811 		ubi_warn("skip auto-resize because of R/O mode");
812 		return 0;
813 	}
814 
815 	/*
816 	 * Clear the auto-resize flag in the volume in-memory copy of the
817 	 * volume table, and 'ubi_resize_volume()' will propagate this change
818 	 * to the flash.
819 	 */
820 	ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;
821 
822 	if (ubi->avail_pebs == 0) {
823 		struct ubi_vtbl_record vtbl_rec;
824 
825 		/*
826 		 * No available PEBs to re-size the volume, clear the flag on
827 		 * flash and exit.
828 		 */
829 		vtbl_rec = ubi->vtbl[vol_id];
830 		err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
831 		if (err)
832 			ubi_err("cannot clean auto-resize flag for volume %d",
833 				vol_id);
834 	} else {
835 		desc.vol = vol;
836 		err = ubi_resize_volume(&desc,
837 					old_reserved_pebs + ubi->avail_pebs);
838 		if (err)
839 			ubi_err("cannot auto-resize volume %d", vol_id);
840 	}
841 
842 	if (err)
843 		return err;
844 
845 	ubi_msg("volume %d (\"%s\") re-sized from %d to %d LEBs", vol_id,
846 		vol->name, old_reserved_pebs, vol->reserved_pebs);
847 	return 0;
848 }
849 
850 /**
851  * ubi_attach_mtd_dev - attach an MTD device.
852  * @mtd: MTD device description object
853  * @ubi_num: number to assign to the new UBI device
854  * @vid_hdr_offset: VID header offset
855  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
856  *
857  * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
858  * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
859  * which case this function finds a vacant device number and assigns it
860  * automatically. Returns the new UBI device number in case of success and a
861  * negative error code in case of failure.
862  *
863  * Note, the invocations of this function has to be serialized by the
864  * @ubi_devices_mutex.
865  */
866 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
867 		       int vid_hdr_offset, int max_beb_per1024)
868 {
869 	struct ubi_device *ubi;
870 	int i, err, ref = 0;
871 
872 	if (max_beb_per1024 < 0 || max_beb_per1024 > MAX_MTD_UBI_BEB_LIMIT)
873 		return -EINVAL;
874 
875 	if (!max_beb_per1024)
876 		max_beb_per1024 = CONFIG_MTD_UBI_BEB_LIMIT;
877 
878 	/*
879 	 * Check if we already have the same MTD device attached.
880 	 *
881 	 * Note, this function assumes that UBI devices creations and deletions
882 	 * are serialized, so it does not take the &ubi_devices_lock.
883 	 */
884 	for (i = 0; i < UBI_MAX_DEVICES; i++) {
885 		ubi = ubi_devices[i];
886 		if (ubi && mtd->index == ubi->mtd->index) {
887 			ubi_err("mtd%d is already attached to ubi%d",
888 				mtd->index, i);
889 			return -EEXIST;
890 		}
891 	}
892 
893 	/*
894 	 * Make sure this MTD device is not emulated on top of an UBI volume
895 	 * already. Well, generally this recursion works fine, but there are
896 	 * different problems like the UBI module takes a reference to itself
897 	 * by attaching (and thus, opening) the emulated MTD device. This
898 	 * results in inability to unload the module. And in general it makes
899 	 * no sense to attach emulated MTD devices, so we prohibit this.
900 	 */
901 	if (mtd->type == MTD_UBIVOLUME) {
902 		ubi_err("refuse attaching mtd%d - it is already emulated on top of UBI",
903 			mtd->index);
904 		return -EINVAL;
905 	}
906 
907 	if (ubi_num == UBI_DEV_NUM_AUTO) {
908 		/* Search for an empty slot in the @ubi_devices array */
909 		for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
910 			if (!ubi_devices[ubi_num])
911 				break;
912 		if (ubi_num == UBI_MAX_DEVICES) {
913 			ubi_err("only %d UBI devices may be created",
914 				UBI_MAX_DEVICES);
915 			return -ENFILE;
916 		}
917 	} else {
918 		if (ubi_num >= UBI_MAX_DEVICES)
919 			return -EINVAL;
920 
921 		/* Make sure ubi_num is not busy */
922 		if (ubi_devices[ubi_num]) {
923 			ubi_err("ubi%d already exists", ubi_num);
924 			return -EEXIST;
925 		}
926 	}
927 
928 	ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
929 	if (!ubi)
930 		return -ENOMEM;
931 
932 	ubi->mtd = mtd;
933 	ubi->ubi_num = ubi_num;
934 	ubi->vid_hdr_offset = vid_hdr_offset;
935 	ubi->autoresize_vol_id = -1;
936 
937 #ifdef CONFIG_MTD_UBI_FASTMAP
938 	ubi->fm_pool.used = ubi->fm_pool.size = 0;
939 	ubi->fm_wl_pool.used = ubi->fm_wl_pool.size = 0;
940 
941 	/*
942 	 * fm_pool.max_size is 5% of the total number of PEBs but it's also
943 	 * between UBI_FM_MAX_POOL_SIZE and UBI_FM_MIN_POOL_SIZE.
944 	 */
945 	ubi->fm_pool.max_size = min(((int)mtd_div_by_eb(ubi->mtd->size,
946 		ubi->mtd) / 100) * 5, UBI_FM_MAX_POOL_SIZE);
947 	if (ubi->fm_pool.max_size < UBI_FM_MIN_POOL_SIZE)
948 		ubi->fm_pool.max_size = UBI_FM_MIN_POOL_SIZE;
949 
950 	ubi->fm_wl_pool.max_size = UBI_FM_WL_POOL_SIZE;
951 	ubi->fm_disabled = !fm_autoconvert;
952 
953 	if (!ubi->fm_disabled && (int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd)
954 	    <= UBI_FM_MAX_START) {
955 		ubi_err("More than %i PEBs are needed for fastmap, sorry.",
956 			UBI_FM_MAX_START);
957 		ubi->fm_disabled = 1;
958 	}
959 
960 	ubi_msg("default fastmap pool size: %d", ubi->fm_pool.max_size);
961 	ubi_msg("default fastmap WL pool size: %d", ubi->fm_wl_pool.max_size);
962 #else
963 	ubi->fm_disabled = 1;
964 #endif
965 	mutex_init(&ubi->buf_mutex);
966 	mutex_init(&ubi->ckvol_mutex);
967 	mutex_init(&ubi->device_mutex);
968 	spin_lock_init(&ubi->volumes_lock);
969 	mutex_init(&ubi->fm_mutex);
970 	init_rwsem(&ubi->fm_sem);
971 
972 	ubi_msg("attaching mtd%d to ubi%d", mtd->index, ubi_num);
973 
974 	err = io_init(ubi, max_beb_per1024);
975 	if (err)
976 		goto out_free;
977 
978 	err = -ENOMEM;
979 	ubi->peb_buf = vmalloc(ubi->peb_size);
980 	if (!ubi->peb_buf)
981 		goto out_free;
982 
983 #ifdef CONFIG_MTD_UBI_FASTMAP
984 	ubi->fm_size = ubi_calc_fm_size(ubi);
985 	ubi->fm_buf = vzalloc(ubi->fm_size);
986 	if (!ubi->fm_buf)
987 		goto out_free;
988 #endif
989 	err = ubi_attach(ubi, 0);
990 	if (err) {
991 		ubi_err("failed to attach mtd%d, error %d", mtd->index, err);
992 		goto out_free;
993 	}
994 
995 	if (ubi->autoresize_vol_id != -1) {
996 		err = autoresize(ubi, ubi->autoresize_vol_id);
997 		if (err)
998 			goto out_detach;
999 	}
1000 
1001 	err = uif_init(ubi, &ref);
1002 	if (err)
1003 		goto out_detach;
1004 
1005 	err = ubi_debugfs_init_dev(ubi);
1006 	if (err)
1007 		goto out_uif;
1008 
1009 	ubi->bgt_thread = kthread_create(ubi_thread, ubi, "%s", ubi->bgt_name);
1010 	if (IS_ERR(ubi->bgt_thread)) {
1011 		err = PTR_ERR(ubi->bgt_thread);
1012 		ubi_err("cannot spawn \"%s\", error %d", ubi->bgt_name,
1013 			err);
1014 		goto out_debugfs;
1015 	}
1016 
1017 	ubi_msg("attached mtd%d (name \"%s\", size %llu MiB) to ubi%d",
1018 		mtd->index, mtd->name, ubi->flash_size >> 20, ubi_num);
1019 	ubi_msg("PEB size: %d bytes (%d KiB), LEB size: %d bytes",
1020 		ubi->peb_size, ubi->peb_size >> 10, ubi->leb_size);
1021 	ubi_msg("min./max. I/O unit sizes: %d/%d, sub-page size %d",
1022 		ubi->min_io_size, ubi->max_write_size, ubi->hdrs_min_io_size);
1023 	ubi_msg("VID header offset: %d (aligned %d), data offset: %d",
1024 		ubi->vid_hdr_offset, ubi->vid_hdr_aloffset, ubi->leb_start);
1025 	ubi_msg("good PEBs: %d, bad PEBs: %d, corrupted PEBs: %d",
1026 		ubi->good_peb_count, ubi->bad_peb_count, ubi->corr_peb_count);
1027 	ubi_msg("user volume: %d, internal volumes: %d, max. volumes count: %d",
1028 		ubi->vol_count - UBI_INT_VOL_COUNT, UBI_INT_VOL_COUNT,
1029 		ubi->vtbl_slots);
1030 	ubi_msg("max/mean erase counter: %d/%d, WL threshold: %d, image sequence number: %u",
1031 		ubi->max_ec, ubi->mean_ec, CONFIG_MTD_UBI_WL_THRESHOLD,
1032 		ubi->image_seq);
1033 	ubi_msg("available PEBs: %d, total reserved PEBs: %d, PEBs reserved for bad PEB handling: %d",
1034 		ubi->avail_pebs, ubi->rsvd_pebs, ubi->beb_rsvd_pebs);
1035 
1036 	/*
1037 	 * The below lock makes sure we do not race with 'ubi_thread()' which
1038 	 * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
1039 	 */
1040 	spin_lock(&ubi->wl_lock);
1041 	ubi->thread_enabled = 1;
1042 	wake_up_process(ubi->bgt_thread);
1043 	spin_unlock(&ubi->wl_lock);
1044 
1045 	ubi_devices[ubi_num] = ubi;
1046 	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
1047 	return ubi_num;
1048 
1049 out_debugfs:
1050 	ubi_debugfs_exit_dev(ubi);
1051 out_uif:
1052 	get_device(&ubi->dev);
1053 	ubi_assert(ref);
1054 	uif_close(ubi);
1055 out_detach:
1056 	ubi_wl_close(ubi);
1057 	ubi_free_internal_volumes(ubi);
1058 	vfree(ubi->vtbl);
1059 out_free:
1060 	vfree(ubi->peb_buf);
1061 	vfree(ubi->fm_buf);
1062 	if (ref)
1063 		put_device(&ubi->dev);
1064 	else
1065 		kfree(ubi);
1066 	return err;
1067 }
1068 
1069 /**
1070  * ubi_detach_mtd_dev - detach an MTD device.
1071  * @ubi_num: UBI device number to detach from
1072  * @anyway: detach MTD even if device reference count is not zero
1073  *
1074  * This function destroys an UBI device number @ubi_num and detaches the
1075  * underlying MTD device. Returns zero in case of success and %-EBUSY if the
1076  * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
1077  * exist.
1078  *
1079  * Note, the invocations of this function has to be serialized by the
1080  * @ubi_devices_mutex.
1081  */
1082 int ubi_detach_mtd_dev(int ubi_num, int anyway)
1083 {
1084 	struct ubi_device *ubi;
1085 
1086 	if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
1087 		return -EINVAL;
1088 
1089 	ubi = ubi_get_device(ubi_num);
1090 	if (!ubi)
1091 		return -EINVAL;
1092 
1093 	spin_lock(&ubi_devices_lock);
1094 	put_device(&ubi->dev);
1095 	ubi->ref_count -= 1;
1096 	if (ubi->ref_count) {
1097 		if (!anyway) {
1098 			spin_unlock(&ubi_devices_lock);
1099 			return -EBUSY;
1100 		}
1101 		/* This may only happen if there is a bug */
1102 		ubi_err("%s reference count %d, destroy anyway",
1103 			ubi->ubi_name, ubi->ref_count);
1104 	}
1105 	ubi_devices[ubi_num] = NULL;
1106 	spin_unlock(&ubi_devices_lock);
1107 
1108 	ubi_assert(ubi_num == ubi->ubi_num);
1109 	ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
1110 	ubi_msg("detaching mtd%d from ubi%d", ubi->mtd->index, ubi_num);
1111 #ifdef CONFIG_MTD_UBI_FASTMAP
1112 	/* If we don't write a new fastmap at detach time we lose all
1113 	 * EC updates that have been made since the last written fastmap. */
1114 	ubi_update_fastmap(ubi);
1115 #endif
1116 	/*
1117 	 * Before freeing anything, we have to stop the background thread to
1118 	 * prevent it from doing anything on this device while we are freeing.
1119 	 */
1120 	if (ubi->bgt_thread)
1121 		kthread_stop(ubi->bgt_thread);
1122 
1123 	/*
1124 	 * Get a reference to the device in order to prevent 'dev_release()'
1125 	 * from freeing the @ubi object.
1126 	 */
1127 	get_device(&ubi->dev);
1128 
1129 	ubi_debugfs_exit_dev(ubi);
1130 	uif_close(ubi);
1131 
1132 	ubi_wl_close(ubi);
1133 	ubi_free_internal_volumes(ubi);
1134 	vfree(ubi->vtbl);
1135 	put_mtd_device(ubi->mtd);
1136 	vfree(ubi->peb_buf);
1137 	vfree(ubi->fm_buf);
1138 	ubi_msg("mtd%d is detached from ubi%d", ubi->mtd->index, ubi->ubi_num);
1139 	put_device(&ubi->dev);
1140 	return 0;
1141 }
1142 
1143 /**
1144  * open_mtd_by_chdev - open an MTD device by its character device node path.
1145  * @mtd_dev: MTD character device node path
1146  *
1147  * This helper function opens an MTD device by its character node device path.
1148  * Returns MTD device description object in case of success and a negative
1149  * error code in case of failure.
1150  */
1151 static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
1152 {
1153 	int err, major, minor, mode;
1154 	struct path path;
1155 
1156 	/* Probably this is an MTD character device node path */
1157 	err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
1158 	if (err)
1159 		return ERR_PTR(err);
1160 
1161 	/* MTD device number is defined by the major / minor numbers */
1162 	major = imajor(path.dentry->d_inode);
1163 	minor = iminor(path.dentry->d_inode);
1164 	mode = path.dentry->d_inode->i_mode;
1165 	path_put(&path);
1166 	if (major != MTD_CHAR_MAJOR || !S_ISCHR(mode))
1167 		return ERR_PTR(-EINVAL);
1168 
1169 	if (minor & 1)
1170 		/*
1171 		 * Just do not think the "/dev/mtdrX" devices support is need,
1172 		 * so do not support them to avoid doing extra work.
1173 		 */
1174 		return ERR_PTR(-EINVAL);
1175 
1176 	return get_mtd_device(NULL, minor / 2);
1177 }
1178 
1179 /**
1180  * open_mtd_device - open MTD device by name, character device path, or number.
1181  * @mtd_dev: name, character device node path, or MTD device device number
1182  *
1183  * This function tries to open and MTD device described by @mtd_dev string,
1184  * which is first treated as ASCII MTD device number, and if it is not true, it
1185  * is treated as MTD device name, and if that is also not true, it is treated
1186  * as MTD character device node path. Returns MTD device description object in
1187  * case of success and a negative error code in case of failure.
1188  */
1189 static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
1190 {
1191 	struct mtd_info *mtd;
1192 	int mtd_num;
1193 	char *endp;
1194 
1195 	mtd_num = simple_strtoul(mtd_dev, &endp, 0);
1196 	if (*endp != '\0' || mtd_dev == endp) {
1197 		/*
1198 		 * This does not look like an ASCII integer, probably this is
1199 		 * MTD device name.
1200 		 */
1201 		mtd = get_mtd_device_nm(mtd_dev);
1202 		if (IS_ERR(mtd) && PTR_ERR(mtd) == -ENODEV)
1203 			/* Probably this is an MTD character device node path */
1204 			mtd = open_mtd_by_chdev(mtd_dev);
1205 	} else
1206 		mtd = get_mtd_device(NULL, mtd_num);
1207 
1208 	return mtd;
1209 }
1210 
1211 static int __init ubi_init(void)
1212 {
1213 	int err, i, k;
1214 
1215 	/* Ensure that EC and VID headers have correct size */
1216 	BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
1217 	BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);
1218 
1219 	if (mtd_devs > UBI_MAX_DEVICES) {
1220 		ubi_err("too many MTD devices, maximum is %d", UBI_MAX_DEVICES);
1221 		return -EINVAL;
1222 	}
1223 
1224 	/* Create base sysfs directory and sysfs files */
1225 	ubi_class = class_create(THIS_MODULE, UBI_NAME_STR);
1226 	if (IS_ERR(ubi_class)) {
1227 		err = PTR_ERR(ubi_class);
1228 		ubi_err("cannot create UBI class");
1229 		goto out;
1230 	}
1231 
1232 	err = class_create_file(ubi_class, &ubi_version);
1233 	if (err) {
1234 		ubi_err("cannot create sysfs file");
1235 		goto out_class;
1236 	}
1237 
1238 	err = misc_register(&ubi_ctrl_cdev);
1239 	if (err) {
1240 		ubi_err("cannot register device");
1241 		goto out_version;
1242 	}
1243 
1244 	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
1245 					      sizeof(struct ubi_wl_entry),
1246 					      0, 0, NULL);
1247 	if (!ubi_wl_entry_slab)
1248 		goto out_dev_unreg;
1249 
1250 	err = ubi_debugfs_init();
1251 	if (err)
1252 		goto out_slab;
1253 
1254 
1255 	/* Attach MTD devices */
1256 	for (i = 0; i < mtd_devs; i++) {
1257 		struct mtd_dev_param *p = &mtd_dev_param[i];
1258 		struct mtd_info *mtd;
1259 
1260 		cond_resched();
1261 
1262 		mtd = open_mtd_device(p->name);
1263 		if (IS_ERR(mtd)) {
1264 			err = PTR_ERR(mtd);
1265 			ubi_err("cannot open mtd %s, error %d", p->name, err);
1266 			/* See comment below re-ubi_is_module(). */
1267 			if (ubi_is_module())
1268 				goto out_detach;
1269 			continue;
1270 		}
1271 
1272 		mutex_lock(&ubi_devices_mutex);
1273 		err = ubi_attach_mtd_dev(mtd, p->ubi_num,
1274 					 p->vid_hdr_offs, p->max_beb_per1024);
1275 		mutex_unlock(&ubi_devices_mutex);
1276 		if (err < 0) {
1277 			ubi_err("cannot attach mtd%d", mtd->index);
1278 			put_mtd_device(mtd);
1279 
1280 			/*
1281 			 * Originally UBI stopped initializing on any error.
1282 			 * However, later on it was found out that this
1283 			 * behavior is not very good when UBI is compiled into
1284 			 * the kernel and the MTD devices to attach are passed
1285 			 * through the command line. Indeed, UBI failure
1286 			 * stopped whole boot sequence.
1287 			 *
1288 			 * To fix this, we changed the behavior for the
1289 			 * non-module case, but preserved the old behavior for
1290 			 * the module case, just for compatibility. This is a
1291 			 * little inconsistent, though.
1292 			 */
1293 			if (ubi_is_module())
1294 				goto out_detach;
1295 		}
1296 	}
1297 
1298 	return 0;
1299 
1300 out_detach:
1301 	for (k = 0; k < i; k++)
1302 		if (ubi_devices[k]) {
1303 			mutex_lock(&ubi_devices_mutex);
1304 			ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
1305 			mutex_unlock(&ubi_devices_mutex);
1306 		}
1307 	ubi_debugfs_exit();
1308 out_slab:
1309 	kmem_cache_destroy(ubi_wl_entry_slab);
1310 out_dev_unreg:
1311 	misc_deregister(&ubi_ctrl_cdev);
1312 out_version:
1313 	class_remove_file(ubi_class, &ubi_version);
1314 out_class:
1315 	class_destroy(ubi_class);
1316 out:
1317 	ubi_err("cannot initialize UBI, error %d", err);
1318 	return err;
1319 }
1320 late_initcall(ubi_init);
1321 
1322 static void __exit ubi_exit(void)
1323 {
1324 	int i;
1325 
1326 	for (i = 0; i < UBI_MAX_DEVICES; i++)
1327 		if (ubi_devices[i]) {
1328 			mutex_lock(&ubi_devices_mutex);
1329 			ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
1330 			mutex_unlock(&ubi_devices_mutex);
1331 		}
1332 	ubi_debugfs_exit();
1333 	kmem_cache_destroy(ubi_wl_entry_slab);
1334 	misc_deregister(&ubi_ctrl_cdev);
1335 	class_remove_file(ubi_class, &ubi_version);
1336 	class_destroy(ubi_class);
1337 }
1338 module_exit(ubi_exit);
1339 
1340 /**
1341  * bytes_str_to_int - convert a number of bytes string into an integer.
1342  * @str: the string to convert
1343  *
1344  * This function returns positive resulting integer in case of success and a
1345  * negative error code in case of failure.
1346  */
1347 static int __init bytes_str_to_int(const char *str)
1348 {
1349 	char *endp;
1350 	unsigned long result;
1351 
1352 	result = simple_strtoul(str, &endp, 0);
1353 	if (str == endp || result >= INT_MAX) {
1354 		ubi_err("incorrect bytes count: \"%s\"\n", str);
1355 		return -EINVAL;
1356 	}
1357 
1358 	switch (*endp) {
1359 	case 'G':
1360 		result *= 1024;
1361 	case 'M':
1362 		result *= 1024;
1363 	case 'K':
1364 		result *= 1024;
1365 		if (endp[1] == 'i' && endp[2] == 'B')
1366 			endp += 2;
1367 	case '\0':
1368 		break;
1369 	default:
1370 		ubi_err("incorrect bytes count: \"%s\"\n", str);
1371 		return -EINVAL;
1372 	}
1373 
1374 	return result;
1375 }
1376 
1377 /**
1378  * ubi_mtd_param_parse - parse the 'mtd=' UBI parameter.
1379  * @val: the parameter value to parse
1380  * @kp: not used
1381  *
1382  * This function returns zero in case of success and a negative error code in
1383  * case of error.
1384  */
1385 static int __init ubi_mtd_param_parse(const char *val, struct kernel_param *kp)
1386 {
1387 	int i, len;
1388 	struct mtd_dev_param *p;
1389 	char buf[MTD_PARAM_LEN_MAX];
1390 	char *pbuf = &buf[0];
1391 	char *tokens[MTD_PARAM_MAX_COUNT], *token;
1392 
1393 	if (!val)
1394 		return -EINVAL;
1395 
1396 	if (mtd_devs == UBI_MAX_DEVICES) {
1397 		ubi_err("too many parameters, max. is %d\n",
1398 			UBI_MAX_DEVICES);
1399 		return -EINVAL;
1400 	}
1401 
1402 	len = strnlen(val, MTD_PARAM_LEN_MAX);
1403 	if (len == MTD_PARAM_LEN_MAX) {
1404 		ubi_err("parameter \"%s\" is too long, max. is %d\n",
1405 			val, MTD_PARAM_LEN_MAX);
1406 		return -EINVAL;
1407 	}
1408 
1409 	if (len == 0) {
1410 		pr_warn("UBI warning: empty 'mtd=' parameter - ignored\n");
1411 		return 0;
1412 	}
1413 
1414 	strcpy(buf, val);
1415 
1416 	/* Get rid of the final newline */
1417 	if (buf[len - 1] == '\n')
1418 		buf[len - 1] = '\0';
1419 
1420 	for (i = 0; i < MTD_PARAM_MAX_COUNT; i++)
1421 		tokens[i] = strsep(&pbuf, ",");
1422 
1423 	if (pbuf) {
1424 		ubi_err("too many arguments at \"%s\"\n", val);
1425 		return -EINVAL;
1426 	}
1427 
1428 	p = &mtd_dev_param[mtd_devs];
1429 	strcpy(&p->name[0], tokens[0]);
1430 
1431 	token = tokens[1];
1432 	if (token) {
1433 		p->vid_hdr_offs = bytes_str_to_int(token);
1434 
1435 		if (p->vid_hdr_offs < 0)
1436 			return p->vid_hdr_offs;
1437 	}
1438 
1439 	token = tokens[2];
1440 	if (token) {
1441 		int err = kstrtoint(token, 10, &p->max_beb_per1024);
1442 
1443 		if (err) {
1444 			ubi_err("bad value for max_beb_per1024 parameter: %s",
1445 				token);
1446 			return -EINVAL;
1447 		}
1448 	}
1449 
1450 	token = tokens[3];
1451 	if (token) {
1452 		int err = kstrtoint(token, 10, &p->ubi_num);
1453 
1454 		if (err) {
1455 			ubi_err("bad value for ubi_num parameter: %s", token);
1456 			return -EINVAL;
1457 		}
1458 	} else
1459 		p->ubi_num = UBI_DEV_NUM_AUTO;
1460 
1461 	mtd_devs += 1;
1462 	return 0;
1463 }
1464 
1465 module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 000);
1466 MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024[,ubi_num]]].\n"
1467 		      "Multiple \"mtd\" parameters may be specified.\n"
1468 		      "MTD devices may be specified by their number, name, or path to the MTD character device node.\n"
1469 		      "Optional \"vid_hdr_offs\" parameter specifies UBI VID header position to be used by UBI. (default value if 0)\n"
1470 		      "Optional \"max_beb_per1024\" parameter specifies the maximum expected bad eraseblock per 1024 eraseblocks. (default value ("
1471 		      __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0)\n"
1472 		      "Optional \"ubi_num\" parameter specifies UBI device number which have to be assigned to the newly created UBI device (assigned automatically by default)\n"
1473 		      "\n"
1474 		      "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
1475 		      "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"
1476 		      "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"
1477 		      "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"
1478 		      "\t(e.g. if the NAND *chipset* has 4096 PEB, 100 will be reserved for this UBI device).");
1479 #ifdef CONFIG_MTD_UBI_FASTMAP
1480 module_param(fm_autoconvert, bool, 0644);
1481 MODULE_PARM_DESC(fm_autoconvert, "Set this parameter to enable fastmap automatically on images without a fastmap.");
1482 #endif
1483 MODULE_VERSION(__stringify(UBI_VERSION));
1484 MODULE_DESCRIPTION("UBI - Unsorted Block Images");
1485 MODULE_AUTHOR("Artem Bityutskiy");
1486 MODULE_LICENSE("GPL");
1487