xref: /openbmc/linux/drivers/mtd/mtdpart.c (revision e5c86679)
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.
51  */
52 static inline struct mtd_part *mtd_to_part(const struct mtd_info *mtd)
53 {
54 	return container_of(mtd, struct mtd_part, mtd);
55 }
56 
57 
58 /*
59  * MTD methods which simply translate the effective address and pass through
60  * to the _real_ device.
61  */
62 
63 static int part_read(struct mtd_info *mtd, loff_t from, size_t len,
64 		size_t *retlen, u_char *buf)
65 {
66 	struct mtd_part *part = mtd_to_part(mtd);
67 	struct mtd_ecc_stats stats;
68 	int res;
69 
70 	stats = part->master->ecc_stats;
71 	res = part->master->_read(part->master, from + part->offset, len,
72 				  retlen, buf);
73 	if (unlikely(mtd_is_eccerr(res)))
74 		mtd->ecc_stats.failed +=
75 			part->master->ecc_stats.failed - stats.failed;
76 	else
77 		mtd->ecc_stats.corrected +=
78 			part->master->ecc_stats.corrected - stats.corrected;
79 	return res;
80 }
81 
82 static int part_point(struct mtd_info *mtd, loff_t from, size_t len,
83 		size_t *retlen, void **virt, resource_size_t *phys)
84 {
85 	struct mtd_part *part = mtd_to_part(mtd);
86 
87 	return part->master->_point(part->master, from + part->offset, len,
88 				    retlen, virt, phys);
89 }
90 
91 static int part_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
92 {
93 	struct mtd_part *part = mtd_to_part(mtd);
94 
95 	return part->master->_unpoint(part->master, from + part->offset, len);
96 }
97 
98 static unsigned long part_get_unmapped_area(struct mtd_info *mtd,
99 					    unsigned long len,
100 					    unsigned long offset,
101 					    unsigned long flags)
102 {
103 	struct mtd_part *part = mtd_to_part(mtd);
104 
105 	offset += part->offset;
106 	return part->master->_get_unmapped_area(part->master, len, offset,
107 						flags);
108 }
109 
110 static int part_read_oob(struct mtd_info *mtd, loff_t from,
111 		struct mtd_oob_ops *ops)
112 {
113 	struct mtd_part *part = mtd_to_part(mtd);
114 	int res;
115 
116 	if (from >= mtd->size)
117 		return -EINVAL;
118 	if (ops->datbuf && from + ops->len > mtd->size)
119 		return -EINVAL;
120 
121 	/*
122 	 * If OOB is also requested, make sure that we do not read past the end
123 	 * of this partition.
124 	 */
125 	if (ops->oobbuf) {
126 		size_t len, pages;
127 
128 		len = mtd_oobavail(mtd, ops);
129 		pages = mtd_div_by_ws(mtd->size, mtd);
130 		pages -= mtd_div_by_ws(from, mtd);
131 		if (ops->ooboffs + ops->ooblen > pages * len)
132 			return -EINVAL;
133 	}
134 
135 	res = part->master->_read_oob(part->master, from + part->offset, ops);
136 	if (unlikely(res)) {
137 		if (mtd_is_bitflip(res))
138 			mtd->ecc_stats.corrected++;
139 		if (mtd_is_eccerr(res))
140 			mtd->ecc_stats.failed++;
141 	}
142 	return res;
143 }
144 
145 static int part_read_user_prot_reg(struct mtd_info *mtd, loff_t from,
146 		size_t len, size_t *retlen, u_char *buf)
147 {
148 	struct mtd_part *part = mtd_to_part(mtd);
149 	return part->master->_read_user_prot_reg(part->master, from, len,
150 						 retlen, buf);
151 }
152 
153 static int part_get_user_prot_info(struct mtd_info *mtd, size_t len,
154 				   size_t *retlen, struct otp_info *buf)
155 {
156 	struct mtd_part *part = mtd_to_part(mtd);
157 	return part->master->_get_user_prot_info(part->master, len, retlen,
158 						 buf);
159 }
160 
161 static int part_read_fact_prot_reg(struct mtd_info *mtd, loff_t from,
162 		size_t len, size_t *retlen, u_char *buf)
163 {
164 	struct mtd_part *part = mtd_to_part(mtd);
165 	return part->master->_read_fact_prot_reg(part->master, from, len,
166 						 retlen, buf);
167 }
168 
169 static int part_get_fact_prot_info(struct mtd_info *mtd, size_t len,
170 				   size_t *retlen, struct otp_info *buf)
171 {
172 	struct mtd_part *part = mtd_to_part(mtd);
173 	return part->master->_get_fact_prot_info(part->master, len, retlen,
174 						 buf);
175 }
176 
177 static int part_write(struct mtd_info *mtd, loff_t to, size_t len,
178 		size_t *retlen, const u_char *buf)
179 {
180 	struct mtd_part *part = mtd_to_part(mtd);
181 	return part->master->_write(part->master, to + part->offset, len,
182 				    retlen, buf);
183 }
184 
185 static int part_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
186 		size_t *retlen, const u_char *buf)
187 {
188 	struct mtd_part *part = mtd_to_part(mtd);
189 	return part->master->_panic_write(part->master, to + part->offset, len,
190 					  retlen, buf);
191 }
192 
193 static int part_write_oob(struct mtd_info *mtd, loff_t to,
194 		struct mtd_oob_ops *ops)
195 {
196 	struct mtd_part *part = mtd_to_part(mtd);
197 
198 	if (to >= mtd->size)
199 		return -EINVAL;
200 	if (ops->datbuf && to + ops->len > mtd->size)
201 		return -EINVAL;
202 	return part->master->_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 = mtd_to_part(mtd);
209 	return part->master->_write_user_prot_reg(part->master, from, len,
210 						  retlen, buf);
211 }
212 
213 static int part_lock_user_prot_reg(struct mtd_info *mtd, loff_t from,
214 		size_t len)
215 {
216 	struct mtd_part *part = mtd_to_part(mtd);
217 	return part->master->_lock_user_prot_reg(part->master, from, len);
218 }
219 
220 static int part_writev(struct mtd_info *mtd, const struct kvec *vecs,
221 		unsigned long count, loff_t to, size_t *retlen)
222 {
223 	struct mtd_part *part = mtd_to_part(mtd);
224 	return part->master->_writev(part->master, vecs, count,
225 				     to + part->offset, retlen);
226 }
227 
228 static int part_erase(struct mtd_info *mtd, struct erase_info *instr)
229 {
230 	struct mtd_part *part = mtd_to_part(mtd);
231 	int ret;
232 
233 	instr->addr += part->offset;
234 	ret = part->master->_erase(part->master, instr);
235 	if (ret) {
236 		if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
237 			instr->fail_addr -= part->offset;
238 		instr->addr -= part->offset;
239 	}
240 	return ret;
241 }
242 
243 void mtd_erase_callback(struct erase_info *instr)
244 {
245 	if (instr->mtd->_erase == part_erase) {
246 		struct mtd_part *part = mtd_to_part(instr->mtd);
247 
248 		if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
249 			instr->fail_addr -= part->offset;
250 		instr->addr -= part->offset;
251 	}
252 	if (instr->callback)
253 		instr->callback(instr);
254 }
255 EXPORT_SYMBOL_GPL(mtd_erase_callback);
256 
257 static int part_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
258 {
259 	struct mtd_part *part = mtd_to_part(mtd);
260 	return part->master->_lock(part->master, ofs + part->offset, len);
261 }
262 
263 static int part_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
264 {
265 	struct mtd_part *part = mtd_to_part(mtd);
266 	return part->master->_unlock(part->master, ofs + part->offset, len);
267 }
268 
269 static int part_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
270 {
271 	struct mtd_part *part = mtd_to_part(mtd);
272 	return part->master->_is_locked(part->master, ofs + part->offset, len);
273 }
274 
275 static void part_sync(struct mtd_info *mtd)
276 {
277 	struct mtd_part *part = mtd_to_part(mtd);
278 	part->master->_sync(part->master);
279 }
280 
281 static int part_suspend(struct mtd_info *mtd)
282 {
283 	struct mtd_part *part = mtd_to_part(mtd);
284 	return part->master->_suspend(part->master);
285 }
286 
287 static void part_resume(struct mtd_info *mtd)
288 {
289 	struct mtd_part *part = mtd_to_part(mtd);
290 	part->master->_resume(part->master);
291 }
292 
293 static int part_block_isreserved(struct mtd_info *mtd, loff_t ofs)
294 {
295 	struct mtd_part *part = mtd_to_part(mtd);
296 	ofs += part->offset;
297 	return part->master->_block_isreserved(part->master, ofs);
298 }
299 
300 static int part_block_isbad(struct mtd_info *mtd, loff_t ofs)
301 {
302 	struct mtd_part *part = mtd_to_part(mtd);
303 	ofs += part->offset;
304 	return part->master->_block_isbad(part->master, ofs);
305 }
306 
307 static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
308 {
309 	struct mtd_part *part = mtd_to_part(mtd);
310 	int res;
311 
312 	ofs += part->offset;
313 	res = part->master->_block_markbad(part->master, ofs);
314 	if (!res)
315 		mtd->ecc_stats.badblocks++;
316 	return res;
317 }
318 
319 static int part_get_device(struct mtd_info *mtd)
320 {
321 	struct mtd_part *part = mtd_to_part(mtd);
322 	return part->master->_get_device(part->master);
323 }
324 
325 static void part_put_device(struct mtd_info *mtd)
326 {
327 	struct mtd_part *part = mtd_to_part(mtd);
328 	part->master->_put_device(part->master);
329 }
330 
331 static int part_ooblayout_ecc(struct mtd_info *mtd, int section,
332 			      struct mtd_oob_region *oobregion)
333 {
334 	struct mtd_part *part = mtd_to_part(mtd);
335 
336 	return mtd_ooblayout_ecc(part->master, section, oobregion);
337 }
338 
339 static int part_ooblayout_free(struct mtd_info *mtd, int section,
340 			       struct mtd_oob_region *oobregion)
341 {
342 	struct mtd_part *part = mtd_to_part(mtd);
343 
344 	return mtd_ooblayout_free(part->master, section, oobregion);
345 }
346 
347 static const struct mtd_ooblayout_ops part_ooblayout_ops = {
348 	.ecc = part_ooblayout_ecc,
349 	.free = part_ooblayout_free,
350 };
351 
352 static int part_max_bad_blocks(struct mtd_info *mtd, loff_t ofs, size_t len)
353 {
354 	struct mtd_part *part = mtd_to_part(mtd);
355 
356 	return part->master->_max_bad_blocks(part->master,
357 					     ofs + part->offset, len);
358 }
359 
360 static inline void free_partition(struct mtd_part *p)
361 {
362 	kfree(p->mtd.name);
363 	kfree(p);
364 }
365 
366 /*
367  * This function unregisters and destroy all slave MTD objects which are
368  * attached to the given master MTD object.
369  */
370 
371 int del_mtd_partitions(struct mtd_info *master)
372 {
373 	struct mtd_part *slave, *next;
374 	int ret, err = 0;
375 
376 	mutex_lock(&mtd_partitions_mutex);
377 	list_for_each_entry_safe(slave, next, &mtd_partitions, list)
378 		if (slave->master == master) {
379 			ret = del_mtd_device(&slave->mtd);
380 			if (ret < 0) {
381 				err = ret;
382 				continue;
383 			}
384 			list_del(&slave->list);
385 			free_partition(slave);
386 		}
387 	mutex_unlock(&mtd_partitions_mutex);
388 
389 	return err;
390 }
391 
392 static struct mtd_part *allocate_partition(struct mtd_info *master,
393 			const struct mtd_partition *part, int partno,
394 			uint64_t cur_offset)
395 {
396 	struct mtd_part *slave;
397 	char *name;
398 
399 	/* allocate the partition structure */
400 	slave = kzalloc(sizeof(*slave), GFP_KERNEL);
401 	name = kstrdup(part->name, GFP_KERNEL);
402 	if (!name || !slave) {
403 		printk(KERN_ERR"memory allocation error while creating partitions for \"%s\"\n",
404 		       master->name);
405 		kfree(name);
406 		kfree(slave);
407 		return ERR_PTR(-ENOMEM);
408 	}
409 
410 	/* set up the MTD object for this partition */
411 	slave->mtd.type = master->type;
412 	slave->mtd.flags = master->flags & ~part->mask_flags;
413 	slave->mtd.size = part->size;
414 	slave->mtd.writesize = master->writesize;
415 	slave->mtd.writebufsize = master->writebufsize;
416 	slave->mtd.oobsize = master->oobsize;
417 	slave->mtd.oobavail = master->oobavail;
418 	slave->mtd.subpage_sft = master->subpage_sft;
419 	slave->mtd.pairing = master->pairing;
420 
421 	slave->mtd.name = name;
422 	slave->mtd.owner = master->owner;
423 
424 	/* NOTE: Historically, we didn't arrange MTDs as a tree out of
425 	 * concern for showing the same data in multiple partitions.
426 	 * However, it is very useful to have the master node present,
427 	 * so the MTD_PARTITIONED_MASTER option allows that. The master
428 	 * will have device nodes etc only if this is set, so make the
429 	 * parent conditional on that option. Note, this is a way to
430 	 * distinguish between the master and the partition in sysfs.
431 	 */
432 	slave->mtd.dev.parent = IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER) ?
433 				&master->dev :
434 				master->dev.parent;
435 	slave->mtd.dev.of_node = part->of_node;
436 
437 	slave->mtd._read = part_read;
438 	slave->mtd._write = part_write;
439 
440 	if (master->_panic_write)
441 		slave->mtd._panic_write = part_panic_write;
442 
443 	if (master->_point && master->_unpoint) {
444 		slave->mtd._point = part_point;
445 		slave->mtd._unpoint = part_unpoint;
446 	}
447 
448 	if (master->_get_unmapped_area)
449 		slave->mtd._get_unmapped_area = part_get_unmapped_area;
450 	if (master->_read_oob)
451 		slave->mtd._read_oob = part_read_oob;
452 	if (master->_write_oob)
453 		slave->mtd._write_oob = part_write_oob;
454 	if (master->_read_user_prot_reg)
455 		slave->mtd._read_user_prot_reg = part_read_user_prot_reg;
456 	if (master->_read_fact_prot_reg)
457 		slave->mtd._read_fact_prot_reg = part_read_fact_prot_reg;
458 	if (master->_write_user_prot_reg)
459 		slave->mtd._write_user_prot_reg = part_write_user_prot_reg;
460 	if (master->_lock_user_prot_reg)
461 		slave->mtd._lock_user_prot_reg = part_lock_user_prot_reg;
462 	if (master->_get_user_prot_info)
463 		slave->mtd._get_user_prot_info = part_get_user_prot_info;
464 	if (master->_get_fact_prot_info)
465 		slave->mtd._get_fact_prot_info = part_get_fact_prot_info;
466 	if (master->_sync)
467 		slave->mtd._sync = part_sync;
468 	if (!partno && !master->dev.class && master->_suspend &&
469 	    master->_resume) {
470 			slave->mtd._suspend = part_suspend;
471 			slave->mtd._resume = part_resume;
472 	}
473 	if (master->_writev)
474 		slave->mtd._writev = part_writev;
475 	if (master->_lock)
476 		slave->mtd._lock = part_lock;
477 	if (master->_unlock)
478 		slave->mtd._unlock = part_unlock;
479 	if (master->_is_locked)
480 		slave->mtd._is_locked = part_is_locked;
481 	if (master->_block_isreserved)
482 		slave->mtd._block_isreserved = part_block_isreserved;
483 	if (master->_block_isbad)
484 		slave->mtd._block_isbad = part_block_isbad;
485 	if (master->_block_markbad)
486 		slave->mtd._block_markbad = part_block_markbad;
487 	if (master->_max_bad_blocks)
488 		slave->mtd._max_bad_blocks = part_max_bad_blocks;
489 
490 	if (master->_get_device)
491 		slave->mtd._get_device = part_get_device;
492 	if (master->_put_device)
493 		slave->mtd._put_device = part_put_device;
494 
495 	slave->mtd._erase = part_erase;
496 	slave->master = master;
497 	slave->offset = part->offset;
498 
499 	if (slave->offset == MTDPART_OFS_APPEND)
500 		slave->offset = cur_offset;
501 	if (slave->offset == MTDPART_OFS_NXTBLK) {
502 		slave->offset = cur_offset;
503 		if (mtd_mod_by_eb(cur_offset, master) != 0) {
504 			/* Round up to next erasesize */
505 			slave->offset = (mtd_div_by_eb(cur_offset, master) + 1) * master->erasesize;
506 			printk(KERN_NOTICE "Moving partition %d: "
507 			       "0x%012llx -> 0x%012llx\n", partno,
508 			       (unsigned long long)cur_offset, (unsigned long long)slave->offset);
509 		}
510 	}
511 	if (slave->offset == MTDPART_OFS_RETAIN) {
512 		slave->offset = cur_offset;
513 		if (master->size - slave->offset >= slave->mtd.size) {
514 			slave->mtd.size = master->size - slave->offset
515 							- slave->mtd.size;
516 		} else {
517 			printk(KERN_ERR "mtd partition \"%s\" doesn't have enough space: %#llx < %#llx, disabled\n",
518 				part->name, master->size - slave->offset,
519 				slave->mtd.size);
520 			/* register to preserve ordering */
521 			goto out_register;
522 		}
523 	}
524 	if (slave->mtd.size == MTDPART_SIZ_FULL)
525 		slave->mtd.size = master->size - slave->offset;
526 
527 	printk(KERN_NOTICE "0x%012llx-0x%012llx : \"%s\"\n", (unsigned long long)slave->offset,
528 		(unsigned long long)(slave->offset + slave->mtd.size), slave->mtd.name);
529 
530 	/* let's do some sanity checks */
531 	if (slave->offset >= master->size) {
532 		/* let's register it anyway to preserve ordering */
533 		slave->offset = 0;
534 		slave->mtd.size = 0;
535 		printk(KERN_ERR"mtd: partition \"%s\" is out of reach -- disabled\n",
536 			part->name);
537 		goto out_register;
538 	}
539 	if (slave->offset + slave->mtd.size > master->size) {
540 		slave->mtd.size = master->size - slave->offset;
541 		printk(KERN_WARNING"mtd: partition \"%s\" extends beyond the end of device \"%s\" -- size truncated to %#llx\n",
542 			part->name, master->name, (unsigned long long)slave->mtd.size);
543 	}
544 	if (master->numeraseregions > 1) {
545 		/* Deal with variable erase size stuff */
546 		int i, max = master->numeraseregions;
547 		u64 end = slave->offset + slave->mtd.size;
548 		struct mtd_erase_region_info *regions = master->eraseregions;
549 
550 		/* Find the first erase regions which is part of this
551 		 * partition. */
552 		for (i = 0; i < max && regions[i].offset <= slave->offset; i++)
553 			;
554 		/* The loop searched for the region _behind_ the first one */
555 		if (i > 0)
556 			i--;
557 
558 		/* Pick biggest erasesize */
559 		for (; i < max && regions[i].offset < end; i++) {
560 			if (slave->mtd.erasesize < regions[i].erasesize) {
561 				slave->mtd.erasesize = regions[i].erasesize;
562 			}
563 		}
564 		BUG_ON(slave->mtd.erasesize == 0);
565 	} else {
566 		/* Single erase size */
567 		slave->mtd.erasesize = master->erasesize;
568 	}
569 
570 	if ((slave->mtd.flags & MTD_WRITEABLE) &&
571 	    mtd_mod_by_eb(slave->offset, &slave->mtd)) {
572 		/* Doesn't start on a boundary of major erase size */
573 		/* FIXME: Let it be writable if it is on a boundary of
574 		 * _minor_ erase size though */
575 		slave->mtd.flags &= ~MTD_WRITEABLE;
576 		printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase block boundary -- force read-only\n",
577 			part->name);
578 	}
579 	if ((slave->mtd.flags & MTD_WRITEABLE) &&
580 	    mtd_mod_by_eb(slave->mtd.size, &slave->mtd)) {
581 		slave->mtd.flags &= ~MTD_WRITEABLE;
582 		printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase block -- force read-only\n",
583 			part->name);
584 	}
585 
586 	mtd_set_ooblayout(&slave->mtd, &part_ooblayout_ops);
587 	slave->mtd.ecc_step_size = master->ecc_step_size;
588 	slave->mtd.ecc_strength = master->ecc_strength;
589 	slave->mtd.bitflip_threshold = master->bitflip_threshold;
590 
591 	if (master->_block_isbad) {
592 		uint64_t offs = 0;
593 
594 		while (offs < slave->mtd.size) {
595 			if (mtd_block_isreserved(master, offs + slave->offset))
596 				slave->mtd.ecc_stats.bbtblocks++;
597 			else if (mtd_block_isbad(master, offs + slave->offset))
598 				slave->mtd.ecc_stats.badblocks++;
599 			offs += slave->mtd.erasesize;
600 		}
601 	}
602 
603 out_register:
604 	return slave;
605 }
606 
607 static ssize_t mtd_partition_offset_show(struct device *dev,
608 		struct device_attribute *attr, char *buf)
609 {
610 	struct mtd_info *mtd = dev_get_drvdata(dev);
611 	struct mtd_part *part = mtd_to_part(mtd);
612 	return snprintf(buf, PAGE_SIZE, "%lld\n", part->offset);
613 }
614 
615 static DEVICE_ATTR(offset, S_IRUGO, mtd_partition_offset_show, NULL);
616 
617 static const struct attribute *mtd_partition_attrs[] = {
618 	&dev_attr_offset.attr,
619 	NULL
620 };
621 
622 static int mtd_add_partition_attrs(struct mtd_part *new)
623 {
624 	int ret = sysfs_create_files(&new->mtd.dev.kobj, mtd_partition_attrs);
625 	if (ret)
626 		printk(KERN_WARNING
627 		       "mtd: failed to create partition attrs, err=%d\n", ret);
628 	return ret;
629 }
630 
631 int mtd_add_partition(struct mtd_info *master, const char *name,
632 		      long long offset, long long length)
633 {
634 	struct mtd_partition part;
635 	struct mtd_part *new;
636 	int ret = 0;
637 
638 	/* the direct offset is expected */
639 	if (offset == MTDPART_OFS_APPEND ||
640 	    offset == MTDPART_OFS_NXTBLK)
641 		return -EINVAL;
642 
643 	if (length == MTDPART_SIZ_FULL)
644 		length = master->size - offset;
645 
646 	if (length <= 0)
647 		return -EINVAL;
648 
649 	memset(&part, 0, sizeof(part));
650 	part.name = name;
651 	part.size = length;
652 	part.offset = offset;
653 
654 	new = allocate_partition(master, &part, -1, offset);
655 	if (IS_ERR(new))
656 		return PTR_ERR(new);
657 
658 	mutex_lock(&mtd_partitions_mutex);
659 	list_add(&new->list, &mtd_partitions);
660 	mutex_unlock(&mtd_partitions_mutex);
661 
662 	add_mtd_device(&new->mtd);
663 
664 	mtd_add_partition_attrs(new);
665 
666 	return ret;
667 }
668 EXPORT_SYMBOL_GPL(mtd_add_partition);
669 
670 int mtd_del_partition(struct mtd_info *master, int partno)
671 {
672 	struct mtd_part *slave, *next;
673 	int ret = -EINVAL;
674 
675 	mutex_lock(&mtd_partitions_mutex);
676 	list_for_each_entry_safe(slave, next, &mtd_partitions, list)
677 		if ((slave->master == master) &&
678 		    (slave->mtd.index == partno)) {
679 			sysfs_remove_files(&slave->mtd.dev.kobj,
680 					   mtd_partition_attrs);
681 			ret = del_mtd_device(&slave->mtd);
682 			if (ret < 0)
683 				break;
684 
685 			list_del(&slave->list);
686 			free_partition(slave);
687 			break;
688 		}
689 	mutex_unlock(&mtd_partitions_mutex);
690 
691 	return ret;
692 }
693 EXPORT_SYMBOL_GPL(mtd_del_partition);
694 
695 /*
696  * This function, given a master MTD object and a partition table, creates
697  * and registers slave MTD objects which are bound to the master according to
698  * the partition definitions.
699  *
700  * For historical reasons, this function's caller only registers the master
701  * if the MTD_PARTITIONED_MASTER config option is set.
702  */
703 
704 int add_mtd_partitions(struct mtd_info *master,
705 		       const struct mtd_partition *parts,
706 		       int nbparts)
707 {
708 	struct mtd_part *slave;
709 	uint64_t cur_offset = 0;
710 	int i;
711 
712 	printk(KERN_NOTICE "Creating %d MTD partitions on \"%s\":\n", nbparts, master->name);
713 
714 	for (i = 0; i < nbparts; i++) {
715 		slave = allocate_partition(master, parts + i, i, cur_offset);
716 		if (IS_ERR(slave)) {
717 			del_mtd_partitions(master);
718 			return PTR_ERR(slave);
719 		}
720 
721 		mutex_lock(&mtd_partitions_mutex);
722 		list_add(&slave->list, &mtd_partitions);
723 		mutex_unlock(&mtd_partitions_mutex);
724 
725 		add_mtd_device(&slave->mtd);
726 		mtd_add_partition_attrs(slave);
727 
728 		cur_offset = slave->offset + slave->mtd.size;
729 	}
730 
731 	return 0;
732 }
733 
734 static DEFINE_SPINLOCK(part_parser_lock);
735 static LIST_HEAD(part_parsers);
736 
737 static struct mtd_part_parser *mtd_part_parser_get(const char *name)
738 {
739 	struct mtd_part_parser *p, *ret = NULL;
740 
741 	spin_lock(&part_parser_lock);
742 
743 	list_for_each_entry(p, &part_parsers, list)
744 		if (!strcmp(p->name, name) && try_module_get(p->owner)) {
745 			ret = p;
746 			break;
747 		}
748 
749 	spin_unlock(&part_parser_lock);
750 
751 	return ret;
752 }
753 
754 static inline void mtd_part_parser_put(const struct mtd_part_parser *p)
755 {
756 	module_put(p->owner);
757 }
758 
759 /*
760  * Many partition parsers just expected the core to kfree() all their data in
761  * one chunk. Do that by default.
762  */
763 static void mtd_part_parser_cleanup_default(const struct mtd_partition *pparts,
764 					    int nr_parts)
765 {
766 	kfree(pparts);
767 }
768 
769 int __register_mtd_parser(struct mtd_part_parser *p, struct module *owner)
770 {
771 	p->owner = owner;
772 
773 	if (!p->cleanup)
774 		p->cleanup = &mtd_part_parser_cleanup_default;
775 
776 	spin_lock(&part_parser_lock);
777 	list_add(&p->list, &part_parsers);
778 	spin_unlock(&part_parser_lock);
779 
780 	return 0;
781 }
782 EXPORT_SYMBOL_GPL(__register_mtd_parser);
783 
784 void deregister_mtd_parser(struct mtd_part_parser *p)
785 {
786 	spin_lock(&part_parser_lock);
787 	list_del(&p->list);
788 	spin_unlock(&part_parser_lock);
789 }
790 EXPORT_SYMBOL_GPL(deregister_mtd_parser);
791 
792 /*
793  * Do not forget to update 'parse_mtd_partitions()' kerneldoc comment if you
794  * are changing this array!
795  */
796 static const char * const default_mtd_part_types[] = {
797 	"cmdlinepart",
798 	"ofpart",
799 	NULL
800 };
801 
802 /**
803  * parse_mtd_partitions - parse MTD partitions
804  * @master: the master partition (describes whole MTD device)
805  * @types: names of partition parsers to try or %NULL
806  * @pparts: info about partitions found is returned here
807  * @data: MTD partition parser-specific data
808  *
809  * This function tries to find partition on MTD device @master. It uses MTD
810  * partition parsers, specified in @types. However, if @types is %NULL, then
811  * the default list of parsers is used. The default list contains only the
812  * "cmdlinepart" and "ofpart" parsers ATM.
813  * Note: If there are more then one parser in @types, the kernel only takes the
814  * partitions parsed out by the first parser.
815  *
816  * This function may return:
817  * o a negative error code in case of failure
818  * o zero otherwise, and @pparts will describe the partitions, number of
819  *   partitions, and the parser which parsed them. Caller must release
820  *   resources with mtd_part_parser_cleanup() when finished with the returned
821  *   data.
822  */
823 int parse_mtd_partitions(struct mtd_info *master, const char *const *types,
824 			 struct mtd_partitions *pparts,
825 			 struct mtd_part_parser_data *data)
826 {
827 	struct mtd_part_parser *parser;
828 	int ret, err = 0;
829 
830 	if (!types)
831 		types = default_mtd_part_types;
832 
833 	for ( ; *types; types++) {
834 		pr_debug("%s: parsing partitions %s\n", master->name, *types);
835 		parser = mtd_part_parser_get(*types);
836 		if (!parser && !request_module("%s", *types))
837 			parser = mtd_part_parser_get(*types);
838 		pr_debug("%s: got parser %s\n", master->name,
839 			 parser ? parser->name : NULL);
840 		if (!parser)
841 			continue;
842 		ret = (*parser->parse_fn)(master, &pparts->parts, data);
843 		pr_debug("%s: parser %s: %i\n",
844 			 master->name, parser->name, ret);
845 		if (ret > 0) {
846 			printk(KERN_NOTICE "%d %s partitions found on MTD device %s\n",
847 			       ret, parser->name, master->name);
848 			pparts->nr_parts = ret;
849 			pparts->parser = parser;
850 			return 0;
851 		}
852 		mtd_part_parser_put(parser);
853 		/*
854 		 * Stash the first error we see; only report it if no parser
855 		 * succeeds
856 		 */
857 		if (ret < 0 && !err)
858 			err = ret;
859 	}
860 	return err;
861 }
862 
863 void mtd_part_parser_cleanup(struct mtd_partitions *parts)
864 {
865 	const struct mtd_part_parser *parser;
866 
867 	if (!parts)
868 		return;
869 
870 	parser = parts->parser;
871 	if (parser) {
872 		if (parser->cleanup)
873 			parser->cleanup(parts->parts, parts->nr_parts);
874 
875 		mtd_part_parser_put(parser);
876 	}
877 }
878 
879 int mtd_is_partition(const struct mtd_info *mtd)
880 {
881 	struct mtd_part *part;
882 	int ispart = 0;
883 
884 	mutex_lock(&mtd_partitions_mutex);
885 	list_for_each_entry(part, &mtd_partitions, list)
886 		if (&part->mtd == mtd) {
887 			ispart = 1;
888 			break;
889 		}
890 	mutex_unlock(&mtd_partitions_mutex);
891 
892 	return ispart;
893 }
894 EXPORT_SYMBOL_GPL(mtd_is_partition);
895 
896 /* Returns the size of the entire flash chip */
897 uint64_t mtd_get_device_size(const struct mtd_info *mtd)
898 {
899 	if (!mtd_is_partition(mtd))
900 		return mtd->size;
901 
902 	return mtd_to_part(mtd)->master->size;
903 }
904 EXPORT_SYMBOL_GPL(mtd_get_device_size);
905