xref: /linux/drivers/mtd/mtdcore.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
1 /*
2  * Core registration and callback routines for MTD
3  * drivers and users.
4  *
5  * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
6  * Copyright © 2006      Red Hat UK Limited
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
21  *
22  */
23 
24 #include <linux/module.h>
25 #include <linux/kernel.h>
26 #include <linux/ptrace.h>
27 #include <linux/seq_file.h>
28 #include <linux/string.h>
29 #include <linux/timer.h>
30 #include <linux/major.h>
31 #include <linux/fs.h>
32 #include <linux/err.h>
33 #include <linux/ioctl.h>
34 #include <linux/init.h>
35 #include <linux/proc_fs.h>
36 #include <linux/idr.h>
37 #include <linux/backing-dev.h>
38 #include <linux/gfp.h>
39 
40 #include <linux/mtd/mtd.h>
41 #include <linux/mtd/partitions.h>
42 
43 #include "mtdcore.h"
44 /*
45  * backing device capabilities for non-mappable devices (such as NAND flash)
46  * - permits private mappings, copies are taken of the data
47  */
48 static struct backing_dev_info mtd_bdi_unmappable = {
49 	.capabilities	= BDI_CAP_MAP_COPY,
50 };
51 
52 /*
53  * backing device capabilities for R/O mappable devices (such as ROM)
54  * - permits private mappings, copies are taken of the data
55  * - permits non-writable shared mappings
56  */
57 static struct backing_dev_info mtd_bdi_ro_mappable = {
58 	.capabilities	= (BDI_CAP_MAP_COPY | BDI_CAP_MAP_DIRECT |
59 			   BDI_CAP_EXEC_MAP | BDI_CAP_READ_MAP),
60 };
61 
62 /*
63  * backing device capabilities for writable mappable devices (such as RAM)
64  * - permits private mappings, copies are taken of the data
65  * - permits non-writable shared mappings
66  */
67 static struct backing_dev_info mtd_bdi_rw_mappable = {
68 	.capabilities	= (BDI_CAP_MAP_COPY | BDI_CAP_MAP_DIRECT |
69 			   BDI_CAP_EXEC_MAP | BDI_CAP_READ_MAP |
70 			   BDI_CAP_WRITE_MAP),
71 };
72 
73 static int mtd_cls_suspend(struct device *dev, pm_message_t state);
74 static int mtd_cls_resume(struct device *dev);
75 
76 static struct class mtd_class = {
77 	.name = "mtd",
78 	.owner = THIS_MODULE,
79 	.suspend = mtd_cls_suspend,
80 	.resume = mtd_cls_resume,
81 };
82 
83 static DEFINE_IDR(mtd_idr);
84 
85 /* These are exported solely for the purpose of mtd_blkdevs.c. You
86    should not use them for _anything_ else */
87 DEFINE_MUTEX(mtd_table_mutex);
88 EXPORT_SYMBOL_GPL(mtd_table_mutex);
89 
90 struct mtd_info *__mtd_next_device(int i)
91 {
92 	return idr_get_next(&mtd_idr, &i);
93 }
94 EXPORT_SYMBOL_GPL(__mtd_next_device);
95 
96 static LIST_HEAD(mtd_notifiers);
97 
98 
99 #if defined(CONFIG_MTD_CHAR) || defined(CONFIG_MTD_CHAR_MODULE)
100 #define MTD_DEVT(index) MKDEV(MTD_CHAR_MAJOR, (index)*2)
101 #else
102 #define MTD_DEVT(index) 0
103 #endif
104 
105 /* REVISIT once MTD uses the driver model better, whoever allocates
106  * the mtd_info will probably want to use the release() hook...
107  */
108 static void mtd_release(struct device *dev)
109 {
110 	struct mtd_info __maybe_unused *mtd = dev_get_drvdata(dev);
111 	dev_t index = MTD_DEVT(mtd->index);
112 
113 	/* remove /dev/mtdXro node if needed */
114 	if (index)
115 		device_destroy(&mtd_class, index + 1);
116 }
117 
118 static int mtd_cls_suspend(struct device *dev, pm_message_t state)
119 {
120 	struct mtd_info *mtd = dev_get_drvdata(dev);
121 
122 	return mtd ? mtd_suspend(mtd) : 0;
123 }
124 
125 static int mtd_cls_resume(struct device *dev)
126 {
127 	struct mtd_info *mtd = dev_get_drvdata(dev);
128 
129 	if (mtd)
130 		mtd_resume(mtd);
131 	return 0;
132 }
133 
134 static ssize_t mtd_type_show(struct device *dev,
135 		struct device_attribute *attr, char *buf)
136 {
137 	struct mtd_info *mtd = dev_get_drvdata(dev);
138 	char *type;
139 
140 	switch (mtd->type) {
141 	case MTD_ABSENT:
142 		type = "absent";
143 		break;
144 	case MTD_RAM:
145 		type = "ram";
146 		break;
147 	case MTD_ROM:
148 		type = "rom";
149 		break;
150 	case MTD_NORFLASH:
151 		type = "nor";
152 		break;
153 	case MTD_NANDFLASH:
154 		type = "nand";
155 		break;
156 	case MTD_DATAFLASH:
157 		type = "dataflash";
158 		break;
159 	case MTD_UBIVOLUME:
160 		type = "ubi";
161 		break;
162 	default:
163 		type = "unknown";
164 	}
165 
166 	return snprintf(buf, PAGE_SIZE, "%s\n", type);
167 }
168 static DEVICE_ATTR(type, S_IRUGO, mtd_type_show, NULL);
169 
170 static ssize_t mtd_flags_show(struct device *dev,
171 		struct device_attribute *attr, char *buf)
172 {
173 	struct mtd_info *mtd = dev_get_drvdata(dev);
174 
175 	return snprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)mtd->flags);
176 
177 }
178 static DEVICE_ATTR(flags, S_IRUGO, mtd_flags_show, NULL);
179 
180 static ssize_t mtd_size_show(struct device *dev,
181 		struct device_attribute *attr, char *buf)
182 {
183 	struct mtd_info *mtd = dev_get_drvdata(dev);
184 
185 	return snprintf(buf, PAGE_SIZE, "%llu\n",
186 		(unsigned long long)mtd->size);
187 
188 }
189 static DEVICE_ATTR(size, S_IRUGO, mtd_size_show, NULL);
190 
191 static ssize_t mtd_erasesize_show(struct device *dev,
192 		struct device_attribute *attr, char *buf)
193 {
194 	struct mtd_info *mtd = dev_get_drvdata(dev);
195 
196 	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->erasesize);
197 
198 }
199 static DEVICE_ATTR(erasesize, S_IRUGO, mtd_erasesize_show, NULL);
200 
201 static ssize_t mtd_writesize_show(struct device *dev,
202 		struct device_attribute *attr, char *buf)
203 {
204 	struct mtd_info *mtd = dev_get_drvdata(dev);
205 
206 	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->writesize);
207 
208 }
209 static DEVICE_ATTR(writesize, S_IRUGO, mtd_writesize_show, NULL);
210 
211 static ssize_t mtd_subpagesize_show(struct device *dev,
212 		struct device_attribute *attr, char *buf)
213 {
214 	struct mtd_info *mtd = dev_get_drvdata(dev);
215 	unsigned int subpagesize = mtd->writesize >> mtd->subpage_sft;
216 
217 	return snprintf(buf, PAGE_SIZE, "%u\n", subpagesize);
218 
219 }
220 static DEVICE_ATTR(subpagesize, S_IRUGO, mtd_subpagesize_show, NULL);
221 
222 static ssize_t mtd_oobsize_show(struct device *dev,
223 		struct device_attribute *attr, char *buf)
224 {
225 	struct mtd_info *mtd = dev_get_drvdata(dev);
226 
227 	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->oobsize);
228 
229 }
230 static DEVICE_ATTR(oobsize, S_IRUGO, mtd_oobsize_show, NULL);
231 
232 static ssize_t mtd_numeraseregions_show(struct device *dev,
233 		struct device_attribute *attr, char *buf)
234 {
235 	struct mtd_info *mtd = dev_get_drvdata(dev);
236 
237 	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->numeraseregions);
238 
239 }
240 static DEVICE_ATTR(numeraseregions, S_IRUGO, mtd_numeraseregions_show,
241 	NULL);
242 
243 static ssize_t mtd_name_show(struct device *dev,
244 		struct device_attribute *attr, char *buf)
245 {
246 	struct mtd_info *mtd = dev_get_drvdata(dev);
247 
248 	return snprintf(buf, PAGE_SIZE, "%s\n", mtd->name);
249 
250 }
251 static DEVICE_ATTR(name, S_IRUGO, mtd_name_show, NULL);
252 
253 static ssize_t mtd_ecc_strength_show(struct device *dev,
254 				     struct device_attribute *attr, char *buf)
255 {
256 	struct mtd_info *mtd = dev_get_drvdata(dev);
257 
258 	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->ecc_strength);
259 }
260 static DEVICE_ATTR(ecc_strength, S_IRUGO, mtd_ecc_strength_show, NULL);
261 
262 static ssize_t mtd_bitflip_threshold_show(struct device *dev,
263 					  struct device_attribute *attr,
264 					  char *buf)
265 {
266 	struct mtd_info *mtd = dev_get_drvdata(dev);
267 
268 	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->bitflip_threshold);
269 }
270 
271 static ssize_t mtd_bitflip_threshold_store(struct device *dev,
272 					   struct device_attribute *attr,
273 					   const char *buf, size_t count)
274 {
275 	struct mtd_info *mtd = dev_get_drvdata(dev);
276 	unsigned int bitflip_threshold;
277 	int retval;
278 
279 	retval = kstrtouint(buf, 0, &bitflip_threshold);
280 	if (retval)
281 		return retval;
282 
283 	mtd->bitflip_threshold = bitflip_threshold;
284 	return count;
285 }
286 static DEVICE_ATTR(bitflip_threshold, S_IRUGO | S_IWUSR,
287 		   mtd_bitflip_threshold_show,
288 		   mtd_bitflip_threshold_store);
289 
290 static struct attribute *mtd_attrs[] = {
291 	&dev_attr_type.attr,
292 	&dev_attr_flags.attr,
293 	&dev_attr_size.attr,
294 	&dev_attr_erasesize.attr,
295 	&dev_attr_writesize.attr,
296 	&dev_attr_subpagesize.attr,
297 	&dev_attr_oobsize.attr,
298 	&dev_attr_numeraseregions.attr,
299 	&dev_attr_name.attr,
300 	&dev_attr_ecc_strength.attr,
301 	&dev_attr_bitflip_threshold.attr,
302 	NULL,
303 };
304 
305 static struct attribute_group mtd_group = {
306 	.attrs		= mtd_attrs,
307 };
308 
309 static const struct attribute_group *mtd_groups[] = {
310 	&mtd_group,
311 	NULL,
312 };
313 
314 static struct device_type mtd_devtype = {
315 	.name		= "mtd",
316 	.groups		= mtd_groups,
317 	.release	= mtd_release,
318 };
319 
320 /**
321  *	add_mtd_device - register an MTD device
322  *	@mtd: pointer to new MTD device info structure
323  *
324  *	Add a device to the list of MTD devices present in the system, and
325  *	notify each currently active MTD 'user' of its arrival. Returns
326  *	zero on success or 1 on failure, which currently will only happen
327  *	if there is insufficient memory or a sysfs error.
328  */
329 
330 int add_mtd_device(struct mtd_info *mtd)
331 {
332 	struct mtd_notifier *not;
333 	int i, error;
334 
335 	if (!mtd->backing_dev_info) {
336 		switch (mtd->type) {
337 		case MTD_RAM:
338 			mtd->backing_dev_info = &mtd_bdi_rw_mappable;
339 			break;
340 		case MTD_ROM:
341 			mtd->backing_dev_info = &mtd_bdi_ro_mappable;
342 			break;
343 		default:
344 			mtd->backing_dev_info = &mtd_bdi_unmappable;
345 			break;
346 		}
347 	}
348 
349 	BUG_ON(mtd->writesize == 0);
350 	mutex_lock(&mtd_table_mutex);
351 
352 	do {
353 		if (!idr_pre_get(&mtd_idr, GFP_KERNEL))
354 			goto fail_locked;
355 		error = idr_get_new(&mtd_idr, mtd, &i);
356 	} while (error == -EAGAIN);
357 
358 	if (error)
359 		goto fail_locked;
360 
361 	mtd->index = i;
362 	mtd->usecount = 0;
363 
364 	/* default value if not set by driver */
365 	if (mtd->bitflip_threshold == 0)
366 		mtd->bitflip_threshold = mtd->ecc_strength;
367 
368 	if (is_power_of_2(mtd->erasesize))
369 		mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
370 	else
371 		mtd->erasesize_shift = 0;
372 
373 	if (is_power_of_2(mtd->writesize))
374 		mtd->writesize_shift = ffs(mtd->writesize) - 1;
375 	else
376 		mtd->writesize_shift = 0;
377 
378 	mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
379 	mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
380 
381 	/* Some chips always power up locked. Unlock them now */
382 	if ((mtd->flags & MTD_WRITEABLE) && (mtd->flags & MTD_POWERUP_LOCK)) {
383 		error = mtd_unlock(mtd, 0, mtd->size);
384 		if (error && error != -EOPNOTSUPP)
385 			printk(KERN_WARNING
386 			       "%s: unlock failed, writes may not work\n",
387 			       mtd->name);
388 	}
389 
390 	/* Caller should have set dev.parent to match the
391 	 * physical device.
392 	 */
393 	mtd->dev.type = &mtd_devtype;
394 	mtd->dev.class = &mtd_class;
395 	mtd->dev.devt = MTD_DEVT(i);
396 	dev_set_name(&mtd->dev, "mtd%d", i);
397 	dev_set_drvdata(&mtd->dev, mtd);
398 	if (device_register(&mtd->dev) != 0)
399 		goto fail_added;
400 
401 	if (MTD_DEVT(i))
402 		device_create(&mtd_class, mtd->dev.parent,
403 			      MTD_DEVT(i) + 1,
404 			      NULL, "mtd%dro", i);
405 
406 	pr_debug("mtd: Giving out device %d to %s\n", i, mtd->name);
407 	/* No need to get a refcount on the module containing
408 	   the notifier, since we hold the mtd_table_mutex */
409 	list_for_each_entry(not, &mtd_notifiers, list)
410 		not->add(mtd);
411 
412 	mutex_unlock(&mtd_table_mutex);
413 	/* We _know_ we aren't being removed, because
414 	   our caller is still holding us here. So none
415 	   of this try_ nonsense, and no bitching about it
416 	   either. :) */
417 	__module_get(THIS_MODULE);
418 	return 0;
419 
420 fail_added:
421 	idr_remove(&mtd_idr, i);
422 fail_locked:
423 	mutex_unlock(&mtd_table_mutex);
424 	return 1;
425 }
426 
427 /**
428  *	del_mtd_device - unregister an MTD device
429  *	@mtd: pointer to MTD device info structure
430  *
431  *	Remove a device from the list of MTD devices present in the system,
432  *	and notify each currently active MTD 'user' of its departure.
433  *	Returns zero on success or 1 on failure, which currently will happen
434  *	if the requested device does not appear to be present in the list.
435  */
436 
437 int del_mtd_device(struct mtd_info *mtd)
438 {
439 	int ret;
440 	struct mtd_notifier *not;
441 
442 	mutex_lock(&mtd_table_mutex);
443 
444 	if (idr_find(&mtd_idr, mtd->index) != mtd) {
445 		ret = -ENODEV;
446 		goto out_error;
447 	}
448 
449 	/* No need to get a refcount on the module containing
450 		the notifier, since we hold the mtd_table_mutex */
451 	list_for_each_entry(not, &mtd_notifiers, list)
452 		not->remove(mtd);
453 
454 	if (mtd->usecount) {
455 		printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
456 		       mtd->index, mtd->name, mtd->usecount);
457 		ret = -EBUSY;
458 	} else {
459 		device_unregister(&mtd->dev);
460 
461 		idr_remove(&mtd_idr, mtd->index);
462 
463 		module_put(THIS_MODULE);
464 		ret = 0;
465 	}
466 
467 out_error:
468 	mutex_unlock(&mtd_table_mutex);
469 	return ret;
470 }
471 
472 /**
473  * mtd_device_parse_register - parse partitions and register an MTD device.
474  *
475  * @mtd: the MTD device to register
476  * @types: the list of MTD partition probes to try, see
477  *         'parse_mtd_partitions()' for more information
478  * @parser_data: MTD partition parser-specific data
479  * @parts: fallback partition information to register, if parsing fails;
480  *         only valid if %nr_parts > %0
481  * @nr_parts: the number of partitions in parts, if zero then the full
482  *            MTD device is registered if no partition info is found
483  *
484  * This function aggregates MTD partitions parsing (done by
485  * 'parse_mtd_partitions()') and MTD device and partitions registering. It
486  * basically follows the most common pattern found in many MTD drivers:
487  *
488  * * It first tries to probe partitions on MTD device @mtd using parsers
489  *   specified in @types (if @types is %NULL, then the default list of parsers
490  *   is used, see 'parse_mtd_partitions()' for more information). If none are
491  *   found this functions tries to fallback to information specified in
492  *   @parts/@nr_parts.
493  * * If any partitioning info was found, this function registers the found
494  *   partitions.
495  * * If no partitions were found this function just registers the MTD device
496  *   @mtd and exits.
497  *
498  * Returns zero in case of success and a negative error code in case of failure.
499  */
500 int mtd_device_parse_register(struct mtd_info *mtd, const char **types,
501 			      struct mtd_part_parser_data *parser_data,
502 			      const struct mtd_partition *parts,
503 			      int nr_parts)
504 {
505 	int err;
506 	struct mtd_partition *real_parts;
507 
508 	err = parse_mtd_partitions(mtd, types, &real_parts, parser_data);
509 	if (err <= 0 && nr_parts && parts) {
510 		real_parts = kmemdup(parts, sizeof(*parts) * nr_parts,
511 				     GFP_KERNEL);
512 		if (!real_parts)
513 			err = -ENOMEM;
514 		else
515 			err = nr_parts;
516 	}
517 
518 	if (err > 0) {
519 		err = add_mtd_partitions(mtd, real_parts, err);
520 		kfree(real_parts);
521 	} else if (err == 0) {
522 		err = add_mtd_device(mtd);
523 		if (err == 1)
524 			err = -ENODEV;
525 	}
526 
527 	return err;
528 }
529 EXPORT_SYMBOL_GPL(mtd_device_parse_register);
530 
531 /**
532  * mtd_device_unregister - unregister an existing MTD device.
533  *
534  * @master: the MTD device to unregister.  This will unregister both the master
535  *          and any partitions if registered.
536  */
537 int mtd_device_unregister(struct mtd_info *master)
538 {
539 	int err;
540 
541 	err = del_mtd_partitions(master);
542 	if (err)
543 		return err;
544 
545 	if (!device_is_registered(&master->dev))
546 		return 0;
547 
548 	return del_mtd_device(master);
549 }
550 EXPORT_SYMBOL_GPL(mtd_device_unregister);
551 
552 /**
553  *	register_mtd_user - register a 'user' of MTD devices.
554  *	@new: pointer to notifier info structure
555  *
556  *	Registers a pair of callbacks function to be called upon addition
557  *	or removal of MTD devices. Causes the 'add' callback to be immediately
558  *	invoked for each MTD device currently present in the system.
559  */
560 void register_mtd_user (struct mtd_notifier *new)
561 {
562 	struct mtd_info *mtd;
563 
564 	mutex_lock(&mtd_table_mutex);
565 
566 	list_add(&new->list, &mtd_notifiers);
567 
568 	__module_get(THIS_MODULE);
569 
570 	mtd_for_each_device(mtd)
571 		new->add(mtd);
572 
573 	mutex_unlock(&mtd_table_mutex);
574 }
575 EXPORT_SYMBOL_GPL(register_mtd_user);
576 
577 /**
578  *	unregister_mtd_user - unregister a 'user' of MTD devices.
579  *	@old: pointer to notifier info structure
580  *
581  *	Removes a callback function pair from the list of 'users' to be
582  *	notified upon addition or removal of MTD devices. Causes the
583  *	'remove' callback to be immediately invoked for each MTD device
584  *	currently present in the system.
585  */
586 int unregister_mtd_user (struct mtd_notifier *old)
587 {
588 	struct mtd_info *mtd;
589 
590 	mutex_lock(&mtd_table_mutex);
591 
592 	module_put(THIS_MODULE);
593 
594 	mtd_for_each_device(mtd)
595 		old->remove(mtd);
596 
597 	list_del(&old->list);
598 	mutex_unlock(&mtd_table_mutex);
599 	return 0;
600 }
601 EXPORT_SYMBOL_GPL(unregister_mtd_user);
602 
603 /**
604  *	get_mtd_device - obtain a validated handle for an MTD device
605  *	@mtd: last known address of the required MTD device
606  *	@num: internal device number of the required MTD device
607  *
608  *	Given a number and NULL address, return the num'th entry in the device
609  *	table, if any.	Given an address and num == -1, search the device table
610  *	for a device with that address and return if it's still present. Given
611  *	both, return the num'th driver only if its address matches. Return
612  *	error code if not.
613  */
614 struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
615 {
616 	struct mtd_info *ret = NULL, *other;
617 	int err = -ENODEV;
618 
619 	mutex_lock(&mtd_table_mutex);
620 
621 	if (num == -1) {
622 		mtd_for_each_device(other) {
623 			if (other == mtd) {
624 				ret = mtd;
625 				break;
626 			}
627 		}
628 	} else if (num >= 0) {
629 		ret = idr_find(&mtd_idr, num);
630 		if (mtd && mtd != ret)
631 			ret = NULL;
632 	}
633 
634 	if (!ret) {
635 		ret = ERR_PTR(err);
636 		goto out;
637 	}
638 
639 	err = __get_mtd_device(ret);
640 	if (err)
641 		ret = ERR_PTR(err);
642 out:
643 	mutex_unlock(&mtd_table_mutex);
644 	return ret;
645 }
646 EXPORT_SYMBOL_GPL(get_mtd_device);
647 
648 
649 int __get_mtd_device(struct mtd_info *mtd)
650 {
651 	int err;
652 
653 	if (!try_module_get(mtd->owner))
654 		return -ENODEV;
655 
656 	if (mtd->_get_device) {
657 		err = mtd->_get_device(mtd);
658 
659 		if (err) {
660 			module_put(mtd->owner);
661 			return err;
662 		}
663 	}
664 	mtd->usecount++;
665 	return 0;
666 }
667 EXPORT_SYMBOL_GPL(__get_mtd_device);
668 
669 /**
670  *	get_mtd_device_nm - obtain a validated handle for an MTD device by
671  *	device name
672  *	@name: MTD device name to open
673  *
674  * 	This function returns MTD device description structure in case of
675  * 	success and an error code in case of failure.
676  */
677 struct mtd_info *get_mtd_device_nm(const char *name)
678 {
679 	int err = -ENODEV;
680 	struct mtd_info *mtd = NULL, *other;
681 
682 	mutex_lock(&mtd_table_mutex);
683 
684 	mtd_for_each_device(other) {
685 		if (!strcmp(name, other->name)) {
686 			mtd = other;
687 			break;
688 		}
689 	}
690 
691 	if (!mtd)
692 		goto out_unlock;
693 
694 	err = __get_mtd_device(mtd);
695 	if (err)
696 		goto out_unlock;
697 
698 	mutex_unlock(&mtd_table_mutex);
699 	return mtd;
700 
701 out_unlock:
702 	mutex_unlock(&mtd_table_mutex);
703 	return ERR_PTR(err);
704 }
705 EXPORT_SYMBOL_GPL(get_mtd_device_nm);
706 
707 void put_mtd_device(struct mtd_info *mtd)
708 {
709 	mutex_lock(&mtd_table_mutex);
710 	__put_mtd_device(mtd);
711 	mutex_unlock(&mtd_table_mutex);
712 
713 }
714 EXPORT_SYMBOL_GPL(put_mtd_device);
715 
716 void __put_mtd_device(struct mtd_info *mtd)
717 {
718 	--mtd->usecount;
719 	BUG_ON(mtd->usecount < 0);
720 
721 	if (mtd->_put_device)
722 		mtd->_put_device(mtd);
723 
724 	module_put(mtd->owner);
725 }
726 EXPORT_SYMBOL_GPL(__put_mtd_device);
727 
728 /*
729  * Erase is an asynchronous operation.  Device drivers are supposed
730  * to call instr->callback() whenever the operation completes, even
731  * if it completes with a failure.
732  * Callers are supposed to pass a callback function and wait for it
733  * to be called before writing to the block.
734  */
735 int mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
736 {
737 	if (instr->addr > mtd->size || instr->len > mtd->size - instr->addr)
738 		return -EINVAL;
739 	if (!(mtd->flags & MTD_WRITEABLE))
740 		return -EROFS;
741 	instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
742 	if (!instr->len) {
743 		instr->state = MTD_ERASE_DONE;
744 		mtd_erase_callback(instr);
745 		return 0;
746 	}
747 	return mtd->_erase(mtd, instr);
748 }
749 EXPORT_SYMBOL_GPL(mtd_erase);
750 
751 /*
752  * This stuff for eXecute-In-Place. phys is optional and may be set to NULL.
753  */
754 int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
755 	      void **virt, resource_size_t *phys)
756 {
757 	*retlen = 0;
758 	*virt = NULL;
759 	if (phys)
760 		*phys = 0;
761 	if (!mtd->_point)
762 		return -EOPNOTSUPP;
763 	if (from < 0 || from > mtd->size || len > mtd->size - from)
764 		return -EINVAL;
765 	if (!len)
766 		return 0;
767 	return mtd->_point(mtd, from, len, retlen, virt, phys);
768 }
769 EXPORT_SYMBOL_GPL(mtd_point);
770 
771 /* We probably shouldn't allow XIP if the unpoint isn't a NULL */
772 int mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
773 {
774 	if (!mtd->_point)
775 		return -EOPNOTSUPP;
776 	if (from < 0 || from > mtd->size || len > mtd->size - from)
777 		return -EINVAL;
778 	if (!len)
779 		return 0;
780 	return mtd->_unpoint(mtd, from, len);
781 }
782 EXPORT_SYMBOL_GPL(mtd_unpoint);
783 
784 /*
785  * Allow NOMMU mmap() to directly map the device (if not NULL)
786  * - return the address to which the offset maps
787  * - return -ENOSYS to indicate refusal to do the mapping
788  */
789 unsigned long mtd_get_unmapped_area(struct mtd_info *mtd, unsigned long len,
790 				    unsigned long offset, unsigned long flags)
791 {
792 	if (!mtd->_get_unmapped_area)
793 		return -EOPNOTSUPP;
794 	if (offset > mtd->size || len > mtd->size - offset)
795 		return -EINVAL;
796 	return mtd->_get_unmapped_area(mtd, len, offset, flags);
797 }
798 EXPORT_SYMBOL_GPL(mtd_get_unmapped_area);
799 
800 int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
801 	     u_char *buf)
802 {
803 	int ret_code;
804 	*retlen = 0;
805 	if (from < 0 || from > mtd->size || len > mtd->size - from)
806 		return -EINVAL;
807 	if (!len)
808 		return 0;
809 
810 	/*
811 	 * In the absence of an error, drivers return a non-negative integer
812 	 * representing the maximum number of bitflips that were corrected on
813 	 * any one ecc region (if applicable; zero otherwise).
814 	 */
815 	ret_code = mtd->_read(mtd, from, len, retlen, buf);
816 	if (unlikely(ret_code < 0))
817 		return ret_code;
818 	if (mtd->ecc_strength == 0)
819 		return 0;	/* device lacks ecc */
820 	return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
821 }
822 EXPORT_SYMBOL_GPL(mtd_read);
823 
824 int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
825 	      const u_char *buf)
826 {
827 	*retlen = 0;
828 	if (to < 0 || to > mtd->size || len > mtd->size - to)
829 		return -EINVAL;
830 	if (!mtd->_write || !(mtd->flags & MTD_WRITEABLE))
831 		return -EROFS;
832 	if (!len)
833 		return 0;
834 	return mtd->_write(mtd, to, len, retlen, buf);
835 }
836 EXPORT_SYMBOL_GPL(mtd_write);
837 
838 /*
839  * In blackbox flight recorder like scenarios we want to make successful writes
840  * in interrupt context. panic_write() is only intended to be called when its
841  * known the kernel is about to panic and we need the write to succeed. Since
842  * the kernel is not going to be running for much longer, this function can
843  * break locks and delay to ensure the write succeeds (but not sleep).
844  */
845 int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
846 		    const u_char *buf)
847 {
848 	*retlen = 0;
849 	if (!mtd->_panic_write)
850 		return -EOPNOTSUPP;
851 	if (to < 0 || to > mtd->size || len > mtd->size - to)
852 		return -EINVAL;
853 	if (!(mtd->flags & MTD_WRITEABLE))
854 		return -EROFS;
855 	if (!len)
856 		return 0;
857 	return mtd->_panic_write(mtd, to, len, retlen, buf);
858 }
859 EXPORT_SYMBOL_GPL(mtd_panic_write);
860 
861 int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
862 {
863 	int ret_code;
864 	ops->retlen = ops->oobretlen = 0;
865 	if (!mtd->_read_oob)
866 		return -EOPNOTSUPP;
867 	/*
868 	 * In cases where ops->datbuf != NULL, mtd->_read_oob() has semantics
869 	 * similar to mtd->_read(), returning a non-negative integer
870 	 * representing max bitflips. In other cases, mtd->_read_oob() may
871 	 * return -EUCLEAN. In all cases, perform similar logic to mtd_read().
872 	 */
873 	ret_code = mtd->_read_oob(mtd, from, ops);
874 	if (unlikely(ret_code < 0))
875 		return ret_code;
876 	if (mtd->ecc_strength == 0)
877 		return 0;	/* device lacks ecc */
878 	return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
879 }
880 EXPORT_SYMBOL_GPL(mtd_read_oob);
881 
882 /*
883  * Method to access the protection register area, present in some flash
884  * devices. The user data is one time programmable but the factory data is read
885  * only.
886  */
887 int mtd_get_fact_prot_info(struct mtd_info *mtd, struct otp_info *buf,
888 			   size_t len)
889 {
890 	if (!mtd->_get_fact_prot_info)
891 		return -EOPNOTSUPP;
892 	if (!len)
893 		return 0;
894 	return mtd->_get_fact_prot_info(mtd, buf, len);
895 }
896 EXPORT_SYMBOL_GPL(mtd_get_fact_prot_info);
897 
898 int mtd_read_fact_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
899 			   size_t *retlen, u_char *buf)
900 {
901 	*retlen = 0;
902 	if (!mtd->_read_fact_prot_reg)
903 		return -EOPNOTSUPP;
904 	if (!len)
905 		return 0;
906 	return mtd->_read_fact_prot_reg(mtd, from, len, retlen, buf);
907 }
908 EXPORT_SYMBOL_GPL(mtd_read_fact_prot_reg);
909 
910 int mtd_get_user_prot_info(struct mtd_info *mtd, struct otp_info *buf,
911 			   size_t len)
912 {
913 	if (!mtd->_get_user_prot_info)
914 		return -EOPNOTSUPP;
915 	if (!len)
916 		return 0;
917 	return mtd->_get_user_prot_info(mtd, buf, len);
918 }
919 EXPORT_SYMBOL_GPL(mtd_get_user_prot_info);
920 
921 int mtd_read_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
922 			   size_t *retlen, u_char *buf)
923 {
924 	*retlen = 0;
925 	if (!mtd->_read_user_prot_reg)
926 		return -EOPNOTSUPP;
927 	if (!len)
928 		return 0;
929 	return mtd->_read_user_prot_reg(mtd, from, len, retlen, buf);
930 }
931 EXPORT_SYMBOL_GPL(mtd_read_user_prot_reg);
932 
933 int mtd_write_user_prot_reg(struct mtd_info *mtd, loff_t to, size_t len,
934 			    size_t *retlen, u_char *buf)
935 {
936 	*retlen = 0;
937 	if (!mtd->_write_user_prot_reg)
938 		return -EOPNOTSUPP;
939 	if (!len)
940 		return 0;
941 	return mtd->_write_user_prot_reg(mtd, to, len, retlen, buf);
942 }
943 EXPORT_SYMBOL_GPL(mtd_write_user_prot_reg);
944 
945 int mtd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len)
946 {
947 	if (!mtd->_lock_user_prot_reg)
948 		return -EOPNOTSUPP;
949 	if (!len)
950 		return 0;
951 	return mtd->_lock_user_prot_reg(mtd, from, len);
952 }
953 EXPORT_SYMBOL_GPL(mtd_lock_user_prot_reg);
954 
955 /* Chip-supported device locking */
956 int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
957 {
958 	if (!mtd->_lock)
959 		return -EOPNOTSUPP;
960 	if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
961 		return -EINVAL;
962 	if (!len)
963 		return 0;
964 	return mtd->_lock(mtd, ofs, len);
965 }
966 EXPORT_SYMBOL_GPL(mtd_lock);
967 
968 int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
969 {
970 	if (!mtd->_unlock)
971 		return -EOPNOTSUPP;
972 	if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
973 		return -EINVAL;
974 	if (!len)
975 		return 0;
976 	return mtd->_unlock(mtd, ofs, len);
977 }
978 EXPORT_SYMBOL_GPL(mtd_unlock);
979 
980 int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
981 {
982 	if (!mtd->_is_locked)
983 		return -EOPNOTSUPP;
984 	if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
985 		return -EINVAL;
986 	if (!len)
987 		return 0;
988 	return mtd->_is_locked(mtd, ofs, len);
989 }
990 EXPORT_SYMBOL_GPL(mtd_is_locked);
991 
992 int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs)
993 {
994 	if (!mtd->_block_isbad)
995 		return 0;
996 	if (ofs < 0 || ofs > mtd->size)
997 		return -EINVAL;
998 	return mtd->_block_isbad(mtd, ofs);
999 }
1000 EXPORT_SYMBOL_GPL(mtd_block_isbad);
1001 
1002 int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs)
1003 {
1004 	if (!mtd->_block_markbad)
1005 		return -EOPNOTSUPP;
1006 	if (ofs < 0 || ofs > mtd->size)
1007 		return -EINVAL;
1008 	if (!(mtd->flags & MTD_WRITEABLE))
1009 		return -EROFS;
1010 	return mtd->_block_markbad(mtd, ofs);
1011 }
1012 EXPORT_SYMBOL_GPL(mtd_block_markbad);
1013 
1014 /*
1015  * default_mtd_writev - the default writev method
1016  * @mtd: mtd device description object pointer
1017  * @vecs: the vectors to write
1018  * @count: count of vectors in @vecs
1019  * @to: the MTD device offset to write to
1020  * @retlen: on exit contains the count of bytes written to the MTD device.
1021  *
1022  * This function returns zero in case of success and a negative error code in
1023  * case of failure.
1024  */
1025 static int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
1026 			      unsigned long count, loff_t to, size_t *retlen)
1027 {
1028 	unsigned long i;
1029 	size_t totlen = 0, thislen;
1030 	int ret = 0;
1031 
1032 	for (i = 0; i < count; i++) {
1033 		if (!vecs[i].iov_len)
1034 			continue;
1035 		ret = mtd_write(mtd, to, vecs[i].iov_len, &thislen,
1036 				vecs[i].iov_base);
1037 		totlen += thislen;
1038 		if (ret || thislen != vecs[i].iov_len)
1039 			break;
1040 		to += vecs[i].iov_len;
1041 	}
1042 	*retlen = totlen;
1043 	return ret;
1044 }
1045 
1046 /*
1047  * mtd_writev - the vector-based MTD write method
1048  * @mtd: mtd device description object pointer
1049  * @vecs: the vectors to write
1050  * @count: count of vectors in @vecs
1051  * @to: the MTD device offset to write to
1052  * @retlen: on exit contains the count of bytes written to the MTD device.
1053  *
1054  * This function returns zero in case of success and a negative error code in
1055  * case of failure.
1056  */
1057 int mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
1058 	       unsigned long count, loff_t to, size_t *retlen)
1059 {
1060 	*retlen = 0;
1061 	if (!(mtd->flags & MTD_WRITEABLE))
1062 		return -EROFS;
1063 	if (!mtd->_writev)
1064 		return default_mtd_writev(mtd, vecs, count, to, retlen);
1065 	return mtd->_writev(mtd, vecs, count, to, retlen);
1066 }
1067 EXPORT_SYMBOL_GPL(mtd_writev);
1068 
1069 /**
1070  * mtd_kmalloc_up_to - allocate a contiguous buffer up to the specified size
1071  * @mtd: mtd device description object pointer
1072  * @size: a pointer to the ideal or maximum size of the allocation, points
1073  *        to the actual allocation size on success.
1074  *
1075  * This routine attempts to allocate a contiguous kernel buffer up to
1076  * the specified size, backing off the size of the request exponentially
1077  * until the request succeeds or until the allocation size falls below
1078  * the system page size. This attempts to make sure it does not adversely
1079  * impact system performance, so when allocating more than one page, we
1080  * ask the memory allocator to avoid re-trying, swapping, writing back
1081  * or performing I/O.
1082  *
1083  * Note, this function also makes sure that the allocated buffer is aligned to
1084  * the MTD device's min. I/O unit, i.e. the "mtd->writesize" value.
1085  *
1086  * This is called, for example by mtd_{read,write} and jffs2_scan_medium,
1087  * to handle smaller (i.e. degraded) buffer allocations under low- or
1088  * fragmented-memory situations where such reduced allocations, from a
1089  * requested ideal, are allowed.
1090  *
1091  * Returns a pointer to the allocated buffer on success; otherwise, NULL.
1092  */
1093 void *mtd_kmalloc_up_to(const struct mtd_info *mtd, size_t *size)
1094 {
1095 	gfp_t flags = __GFP_NOWARN | __GFP_WAIT |
1096 		       __GFP_NORETRY | __GFP_NO_KSWAPD;
1097 	size_t min_alloc = max_t(size_t, mtd->writesize, PAGE_SIZE);
1098 	void *kbuf;
1099 
1100 	*size = min_t(size_t, *size, KMALLOC_MAX_SIZE);
1101 
1102 	while (*size > min_alloc) {
1103 		kbuf = kmalloc(*size, flags);
1104 		if (kbuf)
1105 			return kbuf;
1106 
1107 		*size >>= 1;
1108 		*size = ALIGN(*size, mtd->writesize);
1109 	}
1110 
1111 	/*
1112 	 * For the last resort allocation allow 'kmalloc()' to do all sorts of
1113 	 * things (write-back, dropping caches, etc) by using GFP_KERNEL.
1114 	 */
1115 	return kmalloc(*size, GFP_KERNEL);
1116 }
1117 EXPORT_SYMBOL_GPL(mtd_kmalloc_up_to);
1118 
1119 #ifdef CONFIG_PROC_FS
1120 
1121 /*====================================================================*/
1122 /* Support for /proc/mtd */
1123 
1124 static struct proc_dir_entry *proc_mtd;
1125 
1126 static int mtd_proc_show(struct seq_file *m, void *v)
1127 {
1128 	struct mtd_info *mtd;
1129 
1130 	seq_puts(m, "dev:    size   erasesize  name\n");
1131 	mutex_lock(&mtd_table_mutex);
1132 	mtd_for_each_device(mtd) {
1133 		seq_printf(m, "mtd%d: %8.8llx %8.8x \"%s\"\n",
1134 			   mtd->index, (unsigned long long)mtd->size,
1135 			   mtd->erasesize, mtd->name);
1136 	}
1137 	mutex_unlock(&mtd_table_mutex);
1138 	return 0;
1139 }
1140 
1141 static int mtd_proc_open(struct inode *inode, struct file *file)
1142 {
1143 	return single_open(file, mtd_proc_show, NULL);
1144 }
1145 
1146 static const struct file_operations mtd_proc_ops = {
1147 	.open		= mtd_proc_open,
1148 	.read		= seq_read,
1149 	.llseek		= seq_lseek,
1150 	.release	= single_release,
1151 };
1152 #endif /* CONFIG_PROC_FS */
1153 
1154 /*====================================================================*/
1155 /* Init code */
1156 
1157 static int __init mtd_bdi_init(struct backing_dev_info *bdi, const char *name)
1158 {
1159 	int ret;
1160 
1161 	ret = bdi_init(bdi);
1162 	if (!ret)
1163 		ret = bdi_register(bdi, NULL, name);
1164 
1165 	if (ret)
1166 		bdi_destroy(bdi);
1167 
1168 	return ret;
1169 }
1170 
1171 static int __init init_mtd(void)
1172 {
1173 	int ret;
1174 
1175 	ret = class_register(&mtd_class);
1176 	if (ret)
1177 		goto err_reg;
1178 
1179 	ret = mtd_bdi_init(&mtd_bdi_unmappable, "mtd-unmap");
1180 	if (ret)
1181 		goto err_bdi1;
1182 
1183 	ret = mtd_bdi_init(&mtd_bdi_ro_mappable, "mtd-romap");
1184 	if (ret)
1185 		goto err_bdi2;
1186 
1187 	ret = mtd_bdi_init(&mtd_bdi_rw_mappable, "mtd-rwmap");
1188 	if (ret)
1189 		goto err_bdi3;
1190 
1191 #ifdef CONFIG_PROC_FS
1192 	proc_mtd = proc_create("mtd", 0, NULL, &mtd_proc_ops);
1193 #endif /* CONFIG_PROC_FS */
1194 	return 0;
1195 
1196 err_bdi3:
1197 	bdi_destroy(&mtd_bdi_ro_mappable);
1198 err_bdi2:
1199 	bdi_destroy(&mtd_bdi_unmappable);
1200 err_bdi1:
1201 	class_unregister(&mtd_class);
1202 err_reg:
1203 	pr_err("Error registering mtd class or bdi: %d\n", ret);
1204 	return ret;
1205 }
1206 
1207 static void __exit cleanup_mtd(void)
1208 {
1209 #ifdef CONFIG_PROC_FS
1210 	if (proc_mtd)
1211 		remove_proc_entry( "mtd", NULL);
1212 #endif /* CONFIG_PROC_FS */
1213 	class_unregister(&mtd_class);
1214 	bdi_destroy(&mtd_bdi_unmappable);
1215 	bdi_destroy(&mtd_bdi_ro_mappable);
1216 	bdi_destroy(&mtd_bdi_rw_mappable);
1217 }
1218 
1219 module_init(init_mtd);
1220 module_exit(cleanup_mtd);
1221 
1222 MODULE_LICENSE("GPL");
1223 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
1224 MODULE_DESCRIPTION("Core MTD registration and access routines");
1225