xref: /linux/drivers/mtd/mtdpart.c (revision 5def48982b778aaebe201f85af7170b7d0a6619f)
1 /*
2  * Simple MTD partitioning layer
3  *
4  * Copyright © 2000 Nicolas Pitre <nico@fluxnic.net>
5  * Copyright © 2002 Thomas Gleixner <gleixner@linutronix.de>
6  * Copyright © 2000-2010 David Woodhouse <dwmw2@infradead.org>
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/types.h>
26 #include <linux/kernel.h>
27 #include <linux/slab.h>
28 #include <linux/list.h>
29 #include <linux/kmod.h>
30 #include <linux/mtd/mtd.h>
31 #include <linux/mtd/partitions.h>
32 #include <linux/err.h>
33 
34 #include "mtdcore.h"
35 
36 /* Our partition linked list */
37 static LIST_HEAD(mtd_partitions);
38 static DEFINE_MUTEX(mtd_partitions_mutex);
39 
40 /* Our partition node structure */
41 struct mtd_part {
42 	struct mtd_info mtd;
43 	struct mtd_info *master;
44 	uint64_t offset;
45 	struct list_head list;
46 };
47 
48 /*
49  * Given a pointer to the MTD object in the mtd_part structure, we can retrieve
50  * the pointer to that structure with this macro.
51  */
52 #define PART(x)  ((struct mtd_part *)(x))
53 
54 
55 /*
56  * MTD methods which simply translate the effective address and pass through
57  * to the _real_ device.
58  */
59 
60 static int part_read(struct mtd_info *mtd, loff_t from, size_t len,
61 		size_t *retlen, u_char *buf)
62 {
63 	struct mtd_part *part = PART(mtd);
64 	struct mtd_ecc_stats stats;
65 	int res;
66 
67 	stats = part->master->ecc_stats;
68 	res = mtd_read(part->master, from + part->offset, len, retlen, buf);
69 	if (unlikely(res)) {
70 		if (mtd_is_bitflip(res))
71 			mtd->ecc_stats.corrected += part->master->ecc_stats.corrected - stats.corrected;
72 		if (mtd_is_eccerr(res))
73 			mtd->ecc_stats.failed += part->master->ecc_stats.failed - stats.failed;
74 	}
75 	return res;
76 }
77 
78 static int part_point(struct mtd_info *mtd, loff_t from, size_t len,
79 		size_t *retlen, void **virt, resource_size_t *phys)
80 {
81 	struct mtd_part *part = PART(mtd);
82 
83 	return mtd_point(part->master, from + part->offset, len, retlen,
84 			 virt, phys);
85 }
86 
87 static int part_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
88 {
89 	struct mtd_part *part = PART(mtd);
90 
91 	return mtd_unpoint(part->master, from + part->offset, len);
92 }
93 
94 static unsigned long part_get_unmapped_area(struct mtd_info *mtd,
95 					    unsigned long len,
96 					    unsigned long offset,
97 					    unsigned long flags)
98 {
99 	struct mtd_part *part = PART(mtd);
100 
101 	offset += part->offset;
102 	return mtd_get_unmapped_area(part->master, len, offset, flags);
103 }
104 
105 static int part_read_oob(struct mtd_info *mtd, loff_t from,
106 		struct mtd_oob_ops *ops)
107 {
108 	struct mtd_part *part = PART(mtd);
109 	int res;
110 
111 	if (from >= mtd->size)
112 		return -EINVAL;
113 	if (ops->datbuf && from + ops->len > mtd->size)
114 		return -EINVAL;
115 
116 	/*
117 	 * If OOB is also requested, make sure that we do not read past the end
118 	 * of this partition.
119 	 */
120 	if (ops->oobbuf) {
121 		size_t len, pages;
122 
123 		if (ops->mode == MTD_OPS_AUTO_OOB)
124 			len = mtd->oobavail;
125 		else
126 			len = mtd->oobsize;
127 		pages = mtd_div_by_ws(mtd->size, mtd);
128 		pages -= mtd_div_by_ws(from, mtd);
129 		if (ops->ooboffs + ops->ooblen > pages * len)
130 			return -EINVAL;
131 	}
132 
133 	res = mtd_read_oob(part->master, from + part->offset, ops);
134 	if (unlikely(res)) {
135 		if (mtd_is_bitflip(res))
136 			mtd->ecc_stats.corrected++;
137 		if (mtd_is_eccerr(res))
138 			mtd->ecc_stats.failed++;
139 	}
140 	return res;
141 }
142 
143 static int part_read_user_prot_reg(struct mtd_info *mtd, loff_t from,
144 		size_t len, size_t *retlen, u_char *buf)
145 {
146 	struct mtd_part *part = PART(mtd);
147 	return mtd_read_user_prot_reg(part->master, from, len, retlen, buf);
148 }
149 
150 static int part_get_user_prot_info(struct mtd_info *mtd,
151 		struct otp_info *buf, size_t len)
152 {
153 	struct mtd_part *part = PART(mtd);
154 	return mtd_get_user_prot_info(part->master, buf, len);
155 }
156 
157 static int part_read_fact_prot_reg(struct mtd_info *mtd, loff_t from,
158 		size_t len, size_t *retlen, u_char *buf)
159 {
160 	struct mtd_part *part = PART(mtd);
161 	return mtd_read_fact_prot_reg(part->master, from, len, retlen, buf);
162 }
163 
164 static int part_get_fact_prot_info(struct mtd_info *mtd, struct otp_info *buf,
165 		size_t len)
166 {
167 	struct mtd_part *part = PART(mtd);
168 	return mtd_get_fact_prot_info(part->master, buf, len);
169 }
170 
171 static int part_write(struct mtd_info *mtd, loff_t to, size_t len,
172 		size_t *retlen, const u_char *buf)
173 {
174 	struct mtd_part *part = PART(mtd);
175 	if (!(mtd->flags & MTD_WRITEABLE))
176 		return -EROFS;
177 	return mtd_write(part->master, to + part->offset, len, retlen, buf);
178 }
179 
180 static int part_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
181 		size_t *retlen, const u_char *buf)
182 {
183 	struct mtd_part *part = PART(mtd);
184 	if (!(mtd->flags & MTD_WRITEABLE))
185 		return -EROFS;
186 	return mtd_panic_write(part->master, to + part->offset, len, retlen,
187 			       buf);
188 }
189 
190 static int part_write_oob(struct mtd_info *mtd, loff_t to,
191 		struct mtd_oob_ops *ops)
192 {
193 	struct mtd_part *part = PART(mtd);
194 
195 	if (!(mtd->flags & MTD_WRITEABLE))
196 		return -EROFS;
197 
198 	if (to >= mtd->size)
199 		return -EINVAL;
200 	if (ops->datbuf && to + ops->len > mtd->size)
201 		return -EINVAL;
202 	return mtd_write_oob(part->master, to + part->offset, ops);
203 }
204 
205 static int part_write_user_prot_reg(struct mtd_info *mtd, loff_t from,
206 		size_t len, size_t *retlen, u_char *buf)
207 {
208 	struct mtd_part *part = PART(mtd);
209 	return mtd_write_user_prot_reg(part->master, from, len, retlen, buf);
210 }
211 
212 static int part_lock_user_prot_reg(struct mtd_info *mtd, loff_t from,
213 		size_t len)
214 {
215 	struct mtd_part *part = PART(mtd);
216 	return mtd_lock_user_prot_reg(part->master, from, len);
217 }
218 
219 static int part_writev(struct mtd_info *mtd, const struct kvec *vecs,
220 		unsigned long count, loff_t to, size_t *retlen)
221 {
222 	struct mtd_part *part = PART(mtd);
223 	if (!(mtd->flags & MTD_WRITEABLE))
224 		return -EROFS;
225 	return mtd_writev(part->master, vecs, count, to + part->offset,
226 			  retlen);
227 }
228 
229 static int part_erase(struct mtd_info *mtd, struct erase_info *instr)
230 {
231 	struct mtd_part *part = PART(mtd);
232 	int ret;
233 	if (!(mtd->flags & MTD_WRITEABLE))
234 		return -EROFS;
235 	instr->addr += part->offset;
236 	ret = mtd_erase(part->master, instr);
237 	if (ret) {
238 		if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
239 			instr->fail_addr -= part->offset;
240 		instr->addr -= part->offset;
241 	}
242 	return ret;
243 }
244 
245 void mtd_erase_callback(struct erase_info *instr)
246 {
247 	if (instr->mtd->_erase == part_erase) {
248 		struct mtd_part *part = PART(instr->mtd);
249 
250 		if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
251 			instr->fail_addr -= part->offset;
252 		instr->addr -= part->offset;
253 	}
254 	if (instr->callback)
255 		instr->callback(instr);
256 }
257 EXPORT_SYMBOL_GPL(mtd_erase_callback);
258 
259 static int part_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
260 {
261 	struct mtd_part *part = PART(mtd);
262 	return mtd_lock(part->master, ofs + part->offset, len);
263 }
264 
265 static int part_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
266 {
267 	struct mtd_part *part = PART(mtd);
268 	return mtd_unlock(part->master, ofs + part->offset, len);
269 }
270 
271 static int part_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
272 {
273 	struct mtd_part *part = PART(mtd);
274 	return mtd_is_locked(part->master, ofs + part->offset, len);
275 }
276 
277 static void part_sync(struct mtd_info *mtd)
278 {
279 	struct mtd_part *part = PART(mtd);
280 	mtd_sync(part->master);
281 }
282 
283 static int part_suspend(struct mtd_info *mtd)
284 {
285 	struct mtd_part *part = PART(mtd);
286 	return mtd_suspend(part->master);
287 }
288 
289 static void part_resume(struct mtd_info *mtd)
290 {
291 	struct mtd_part *part = PART(mtd);
292 	mtd_resume(part->master);
293 }
294 
295 static int part_block_isbad(struct mtd_info *mtd, loff_t ofs)
296 {
297 	struct mtd_part *part = PART(mtd);
298 	ofs += part->offset;
299 	return mtd_block_isbad(part->master, ofs);
300 }
301 
302 static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
303 {
304 	struct mtd_part *part = PART(mtd);
305 	int res;
306 
307 	if (!(mtd->flags & MTD_WRITEABLE))
308 		return -EROFS;
309 	ofs += part->offset;
310 	res = mtd_block_markbad(part->master, ofs);
311 	if (!res)
312 		mtd->ecc_stats.badblocks++;
313 	return res;
314 }
315 
316 static inline void free_partition(struct mtd_part *p)
317 {
318 	kfree(p->mtd.name);
319 	kfree(p);
320 }
321 
322 /*
323  * This function unregisters and destroy all slave MTD objects which are
324  * attached to the given master MTD object.
325  */
326 
327 int del_mtd_partitions(struct mtd_info *master)
328 {
329 	struct mtd_part *slave, *next;
330 	int ret, err = 0;
331 
332 	mutex_lock(&mtd_partitions_mutex);
333 	list_for_each_entry_safe(slave, next, &mtd_partitions, list)
334 		if (slave->master == master) {
335 			ret = del_mtd_device(&slave->mtd);
336 			if (ret < 0) {
337 				err = ret;
338 				continue;
339 			}
340 			list_del(&slave->list);
341 			free_partition(slave);
342 		}
343 	mutex_unlock(&mtd_partitions_mutex);
344 
345 	return err;
346 }
347 
348 static struct mtd_part *allocate_partition(struct mtd_info *master,
349 			const struct mtd_partition *part, int partno,
350 			uint64_t cur_offset)
351 {
352 	struct mtd_part *slave;
353 	char *name;
354 
355 	/* allocate the partition structure */
356 	slave = kzalloc(sizeof(*slave), GFP_KERNEL);
357 	name = kstrdup(part->name, GFP_KERNEL);
358 	if (!name || !slave) {
359 		printk(KERN_ERR"memory allocation error while creating partitions for \"%s\"\n",
360 		       master->name);
361 		kfree(name);
362 		kfree(slave);
363 		return ERR_PTR(-ENOMEM);
364 	}
365 
366 	/* set up the MTD object for this partition */
367 	slave->mtd.type = master->type;
368 	slave->mtd.flags = master->flags & ~part->mask_flags;
369 	slave->mtd.size = part->size;
370 	slave->mtd.writesize = master->writesize;
371 	slave->mtd.writebufsize = master->writebufsize;
372 	slave->mtd.oobsize = master->oobsize;
373 	slave->mtd.oobavail = master->oobavail;
374 	slave->mtd.subpage_sft = master->subpage_sft;
375 
376 	slave->mtd.name = name;
377 	slave->mtd.owner = master->owner;
378 	slave->mtd.backing_dev_info = master->backing_dev_info;
379 
380 	/* NOTE:  we don't arrange MTDs as a tree; it'd be error-prone
381 	 * to have the same data be in two different partitions.
382 	 */
383 	slave->mtd.dev.parent = master->dev.parent;
384 
385 	slave->mtd._read = part_read;
386 	slave->mtd._write = part_write;
387 
388 	if (master->_panic_write)
389 		slave->mtd._panic_write = part_panic_write;
390 
391 	if (master->_point && master->_unpoint) {
392 		slave->mtd._point = part_point;
393 		slave->mtd._unpoint = part_unpoint;
394 	}
395 
396 	if (master->_get_unmapped_area)
397 		slave->mtd._get_unmapped_area = part_get_unmapped_area;
398 	if (master->_read_oob)
399 		slave->mtd._read_oob = part_read_oob;
400 	if (master->_write_oob)
401 		slave->mtd._write_oob = part_write_oob;
402 	if (master->_read_user_prot_reg)
403 		slave->mtd._read_user_prot_reg = part_read_user_prot_reg;
404 	if (master->_read_fact_prot_reg)
405 		slave->mtd._read_fact_prot_reg = part_read_fact_prot_reg;
406 	if (master->_write_user_prot_reg)
407 		slave->mtd._write_user_prot_reg = part_write_user_prot_reg;
408 	if (master->_lock_user_prot_reg)
409 		slave->mtd._lock_user_prot_reg = part_lock_user_prot_reg;
410 	if (master->_get_user_prot_info)
411 		slave->mtd._get_user_prot_info = part_get_user_prot_info;
412 	if (master->_get_fact_prot_info)
413 		slave->mtd._get_fact_prot_info = part_get_fact_prot_info;
414 	if (master->_sync)
415 		slave->mtd._sync = part_sync;
416 	if (!partno && !master->dev.class && master->_suspend &&
417 	    master->_resume) {
418 			slave->mtd._suspend = part_suspend;
419 			slave->mtd._resume = part_resume;
420 	}
421 	if (master->_writev)
422 		slave->mtd._writev = part_writev;
423 	if (master->_lock)
424 		slave->mtd._lock = part_lock;
425 	if (master->_unlock)
426 		slave->mtd._unlock = part_unlock;
427 	if (master->_is_locked)
428 		slave->mtd._is_locked = part_is_locked;
429 	if (master->_block_isbad)
430 		slave->mtd._block_isbad = part_block_isbad;
431 	if (master->_block_markbad)
432 		slave->mtd._block_markbad = part_block_markbad;
433 	slave->mtd._erase = part_erase;
434 	slave->master = master;
435 	slave->offset = part->offset;
436 
437 	if (slave->offset == MTDPART_OFS_APPEND)
438 		slave->offset = cur_offset;
439 	if (slave->offset == MTDPART_OFS_NXTBLK) {
440 		slave->offset = cur_offset;
441 		if (mtd_mod_by_eb(cur_offset, master) != 0) {
442 			/* Round up to next erasesize */
443 			slave->offset = (mtd_div_by_eb(cur_offset, master) + 1) * master->erasesize;
444 			printk(KERN_NOTICE "Moving partition %d: "
445 			       "0x%012llx -> 0x%012llx\n", partno,
446 			       (unsigned long long)cur_offset, (unsigned long long)slave->offset);
447 		}
448 	}
449 	if (slave->offset == MTDPART_OFS_RETAIN) {
450 		slave->offset = cur_offset;
451 		if (master->size - slave->offset >= slave->mtd.size) {
452 			slave->mtd.size = master->size - slave->offset
453 							- slave->mtd.size;
454 		} else {
455 			printk(KERN_ERR "mtd partition \"%s\" doesn't have enough space: %#llx < %#llx, disabled\n",
456 				part->name, master->size - slave->offset,
457 				slave->mtd.size);
458 			/* register to preserve ordering */
459 			goto out_register;
460 		}
461 	}
462 	if (slave->mtd.size == MTDPART_SIZ_FULL)
463 		slave->mtd.size = master->size - slave->offset;
464 
465 	printk(KERN_NOTICE "0x%012llx-0x%012llx : \"%s\"\n", (unsigned long long)slave->offset,
466 		(unsigned long long)(slave->offset + slave->mtd.size), slave->mtd.name);
467 
468 	/* let's do some sanity checks */
469 	if (slave->offset >= master->size) {
470 		/* let's register it anyway to preserve ordering */
471 		slave->offset = 0;
472 		slave->mtd.size = 0;
473 		printk(KERN_ERR"mtd: partition \"%s\" is out of reach -- disabled\n",
474 			part->name);
475 		goto out_register;
476 	}
477 	if (slave->offset + slave->mtd.size > master->size) {
478 		slave->mtd.size = master->size - slave->offset;
479 		printk(KERN_WARNING"mtd: partition \"%s\" extends beyond the end of device \"%s\" -- size truncated to %#llx\n",
480 			part->name, master->name, (unsigned long long)slave->mtd.size);
481 	}
482 	if (master->numeraseregions > 1) {
483 		/* Deal with variable erase size stuff */
484 		int i, max = master->numeraseregions;
485 		u64 end = slave->offset + slave->mtd.size;
486 		struct mtd_erase_region_info *regions = master->eraseregions;
487 
488 		/* Find the first erase regions which is part of this
489 		 * partition. */
490 		for (i = 0; i < max && regions[i].offset <= slave->offset; i++)
491 			;
492 		/* The loop searched for the region _behind_ the first one */
493 		if (i > 0)
494 			i--;
495 
496 		/* Pick biggest erasesize */
497 		for (; i < max && regions[i].offset < end; i++) {
498 			if (slave->mtd.erasesize < regions[i].erasesize) {
499 				slave->mtd.erasesize = regions[i].erasesize;
500 			}
501 		}
502 		BUG_ON(slave->mtd.erasesize == 0);
503 	} else {
504 		/* Single erase size */
505 		slave->mtd.erasesize = master->erasesize;
506 	}
507 
508 	if ((slave->mtd.flags & MTD_WRITEABLE) &&
509 	    mtd_mod_by_eb(slave->offset, &slave->mtd)) {
510 		/* Doesn't start on a boundary of major erase size */
511 		/* FIXME: Let it be writable if it is on a boundary of
512 		 * _minor_ erase size though */
513 		slave->mtd.flags &= ~MTD_WRITEABLE;
514 		printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase block boundary -- force read-only\n",
515 			part->name);
516 	}
517 	if ((slave->mtd.flags & MTD_WRITEABLE) &&
518 	    mtd_mod_by_eb(slave->mtd.size, &slave->mtd)) {
519 		slave->mtd.flags &= ~MTD_WRITEABLE;
520 		printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase block -- force read-only\n",
521 			part->name);
522 	}
523 
524 	slave->mtd.ecclayout = master->ecclayout;
525 	if (master->_block_isbad) {
526 		uint64_t offs = 0;
527 
528 		while (offs < slave->mtd.size) {
529 			if (mtd_block_isbad(master, offs + slave->offset))
530 				slave->mtd.ecc_stats.badblocks++;
531 			offs += slave->mtd.erasesize;
532 		}
533 	}
534 
535 out_register:
536 	return slave;
537 }
538 
539 int mtd_add_partition(struct mtd_info *master, char *name,
540 		      long long offset, long long length)
541 {
542 	struct mtd_partition part;
543 	struct mtd_part *p, *new;
544 	uint64_t start, end;
545 	int ret = 0;
546 
547 	/* the direct offset is expected */
548 	if (offset == MTDPART_OFS_APPEND ||
549 	    offset == MTDPART_OFS_NXTBLK)
550 		return -EINVAL;
551 
552 	if (length == MTDPART_SIZ_FULL)
553 		length = master->size - offset;
554 
555 	if (length <= 0)
556 		return -EINVAL;
557 
558 	part.name = name;
559 	part.size = length;
560 	part.offset = offset;
561 	part.mask_flags = 0;
562 	part.ecclayout = NULL;
563 
564 	new = allocate_partition(master, &part, -1, offset);
565 	if (IS_ERR(new))
566 		return PTR_ERR(new);
567 
568 	start = offset;
569 	end = offset + length;
570 
571 	mutex_lock(&mtd_partitions_mutex);
572 	list_for_each_entry(p, &mtd_partitions, list)
573 		if (p->master == master) {
574 			if ((start >= p->offset) &&
575 			    (start < (p->offset + p->mtd.size)))
576 				goto err_inv;
577 
578 			if ((end >= p->offset) &&
579 			    (end < (p->offset + p->mtd.size)))
580 				goto err_inv;
581 		}
582 
583 	list_add(&new->list, &mtd_partitions);
584 	mutex_unlock(&mtd_partitions_mutex);
585 
586 	add_mtd_device(&new->mtd);
587 
588 	return ret;
589 err_inv:
590 	mutex_unlock(&mtd_partitions_mutex);
591 	free_partition(new);
592 	return -EINVAL;
593 }
594 EXPORT_SYMBOL_GPL(mtd_add_partition);
595 
596 int mtd_del_partition(struct mtd_info *master, int partno)
597 {
598 	struct mtd_part *slave, *next;
599 	int ret = -EINVAL;
600 
601 	mutex_lock(&mtd_partitions_mutex);
602 	list_for_each_entry_safe(slave, next, &mtd_partitions, list)
603 		if ((slave->master == master) &&
604 		    (slave->mtd.index == partno)) {
605 			ret = del_mtd_device(&slave->mtd);
606 			if (ret < 0)
607 				break;
608 
609 			list_del(&slave->list);
610 			free_partition(slave);
611 			break;
612 		}
613 	mutex_unlock(&mtd_partitions_mutex);
614 
615 	return ret;
616 }
617 EXPORT_SYMBOL_GPL(mtd_del_partition);
618 
619 /*
620  * This function, given a master MTD object and a partition table, creates
621  * and registers slave MTD objects which are bound to the master according to
622  * the partition definitions.
623  *
624  * We don't register the master, or expect the caller to have done so,
625  * for reasons of data integrity.
626  */
627 
628 int add_mtd_partitions(struct mtd_info *master,
629 		       const struct mtd_partition *parts,
630 		       int nbparts)
631 {
632 	struct mtd_part *slave;
633 	uint64_t cur_offset = 0;
634 	int i;
635 
636 	printk(KERN_NOTICE "Creating %d MTD partitions on \"%s\":\n", nbparts, master->name);
637 
638 	for (i = 0; i < nbparts; i++) {
639 		slave = allocate_partition(master, parts + i, i, cur_offset);
640 		if (IS_ERR(slave))
641 			return PTR_ERR(slave);
642 
643 		mutex_lock(&mtd_partitions_mutex);
644 		list_add(&slave->list, &mtd_partitions);
645 		mutex_unlock(&mtd_partitions_mutex);
646 
647 		add_mtd_device(&slave->mtd);
648 
649 		cur_offset = slave->offset + slave->mtd.size;
650 	}
651 
652 	return 0;
653 }
654 
655 static DEFINE_SPINLOCK(part_parser_lock);
656 static LIST_HEAD(part_parsers);
657 
658 static struct mtd_part_parser *get_partition_parser(const char *name)
659 {
660 	struct mtd_part_parser *p, *ret = NULL;
661 
662 	spin_lock(&part_parser_lock);
663 
664 	list_for_each_entry(p, &part_parsers, list)
665 		if (!strcmp(p->name, name) && try_module_get(p->owner)) {
666 			ret = p;
667 			break;
668 		}
669 
670 	spin_unlock(&part_parser_lock);
671 
672 	return ret;
673 }
674 
675 #define put_partition_parser(p) do { module_put((p)->owner); } while (0)
676 
677 int register_mtd_parser(struct mtd_part_parser *p)
678 {
679 	spin_lock(&part_parser_lock);
680 	list_add(&p->list, &part_parsers);
681 	spin_unlock(&part_parser_lock);
682 
683 	return 0;
684 }
685 EXPORT_SYMBOL_GPL(register_mtd_parser);
686 
687 int deregister_mtd_parser(struct mtd_part_parser *p)
688 {
689 	spin_lock(&part_parser_lock);
690 	list_del(&p->list);
691 	spin_unlock(&part_parser_lock);
692 	return 0;
693 }
694 EXPORT_SYMBOL_GPL(deregister_mtd_parser);
695 
696 /*
697  * Do not forget to update 'parse_mtd_partitions()' kerneldoc comment if you
698  * are changing this array!
699  */
700 static const char *default_mtd_part_types[] = {
701 	"cmdlinepart",
702 	"ofpart",
703 	NULL
704 };
705 
706 /**
707  * parse_mtd_partitions - parse MTD partitions
708  * @master: the master partition (describes whole MTD device)
709  * @types: names of partition parsers to try or %NULL
710  * @pparts: array of partitions found is returned here
711  * @data: MTD partition parser-specific data
712  *
713  * This function tries to find partition on MTD device @master. It uses MTD
714  * partition parsers, specified in @types. However, if @types is %NULL, then
715  * the default list of parsers is used. The default list contains only the
716  * "cmdlinepart" and "ofpart" parsers ATM.
717  *
718  * This function may return:
719  * o a negative error code in case of failure
720  * o zero if no partitions were found
721  * o a positive number of found partitions, in which case on exit @pparts will
722  *   point to an array containing this number of &struct mtd_info objects.
723  */
724 int parse_mtd_partitions(struct mtd_info *master, const char **types,
725 			 struct mtd_partition **pparts,
726 			 struct mtd_part_parser_data *data)
727 {
728 	struct mtd_part_parser *parser;
729 	int ret = 0;
730 
731 	if (!types)
732 		types = default_mtd_part_types;
733 
734 	for ( ; ret <= 0 && *types; types++) {
735 		parser = get_partition_parser(*types);
736 		if (!parser && !request_module("%s", *types))
737 			parser = get_partition_parser(*types);
738 		if (!parser)
739 			continue;
740 		ret = (*parser->parse_fn)(master, pparts, data);
741 		if (ret > 0) {
742 			printk(KERN_NOTICE "%d %s partitions found on MTD device %s\n",
743 			       ret, parser->name, master->name);
744 		}
745 		put_partition_parser(parser);
746 	}
747 	return ret;
748 }
749 
750 int mtd_is_partition(struct mtd_info *mtd)
751 {
752 	struct mtd_part *part;
753 	int ispart = 0;
754 
755 	mutex_lock(&mtd_partitions_mutex);
756 	list_for_each_entry(part, &mtd_partitions, list)
757 		if (&part->mtd == mtd) {
758 			ispart = 1;
759 			break;
760 		}
761 	mutex_unlock(&mtd_partitions_mutex);
762 
763 	return ispart;
764 }
765 EXPORT_SYMBOL_GPL(mtd_is_partition);
766