mtdpart.c 26.9 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992
/*
 * Simple MTD partitioning layer
 *
 * Copyright © 2000 Nicolas Pitre <nico@fluxnic.net>
 * Copyright © 2002 Thomas Gleixner <gleixner@linutronix.de>
 * Copyright © 2000-2010 David Woodhouse <dwmw2@infradead.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/kmod.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/err.h>

#include "mtdcore.h"

/* Our partition linked list */
static LIST_HEAD(mtd_partitions);
static DEFINE_MUTEX(mtd_partitions_mutex);

/**
 * struct mtd_part - our partition node structure
 *
 * @mtd: struct holding partition details
 * @parent: parent mtd - flash device or another partition
 * @offset: partition offset relative to the *flash device*
 */
struct mtd_part {
	struct mtd_info mtd;
	struct mtd_info *parent;
	uint64_t offset;
	struct list_head list;
};

/*
 * Given a pointer to the MTD object in the mtd_part structure, we can retrieve
 * the pointer to that structure.
 */
static inline struct mtd_part *mtd_to_part(const struct mtd_info *mtd)
{
	return container_of(mtd, struct mtd_part, mtd);
}


/*
 * MTD methods which simply translate the effective address and pass through
 * to the _real_ device.
 */

static int part_read(struct mtd_info *mtd, loff_t from, size_t len,
		size_t *retlen, u_char *buf)
{
	struct mtd_part *part = mtd_to_part(mtd);
	struct mtd_ecc_stats stats;
	int res;

	stats = part->parent->ecc_stats;
	res = part->parent->_read(part->parent, from + part->offset, len,
				  retlen, buf);
	if (unlikely(mtd_is_eccerr(res)))
		mtd->ecc_stats.failed +=
			part->parent->ecc_stats.failed - stats.failed;
	else
		mtd->ecc_stats.corrected +=
			part->parent->ecc_stats.corrected - stats.corrected;
	return res;
}

static int part_point(struct mtd_info *mtd, loff_t from, size_t len,
		size_t *retlen, void **virt, resource_size_t *phys)
{
	struct mtd_part *part = mtd_to_part(mtd);

	return part->parent->_point(part->parent, from + part->offset, len,
				    retlen, virt, phys);
}

static int part_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
{
	struct mtd_part *part = mtd_to_part(mtd);

	return part->parent->_unpoint(part->parent, from + part->offset, len);
}

static unsigned long part_get_unmapped_area(struct mtd_info *mtd,
					    unsigned long len,
					    unsigned long offset,
					    unsigned long flags)
{
	struct mtd_part *part = mtd_to_part(mtd);

	offset += part->offset;
	return part->parent->_get_unmapped_area(part->parent, len, offset,
						flags);
}

static int part_read_oob(struct mtd_info *mtd, loff_t from,
		struct mtd_oob_ops *ops)
{
	struct mtd_part *part = mtd_to_part(mtd);
	int res;

	if (from >= mtd->size)
		return -EINVAL;
	if (ops->datbuf && from + ops->len > mtd->size)
		return -EINVAL;

	/*
	 * If OOB is also requested, make sure that we do not read past the end
	 * of this partition.
	 */
	if (ops->oobbuf) {
		size_t len, pages;

		len = mtd_oobavail(mtd, ops);
		pages = mtd_div_by_ws(mtd->size, mtd);
		pages -= mtd_div_by_ws(from, mtd);
		if (ops->ooboffs + ops->ooblen > pages * len)
			return -EINVAL;
	}

	res = part->parent->_read_oob(part->parent, from + part->offset, ops);
	if (unlikely(res)) {
		if (mtd_is_bitflip(res))
			mtd->ecc_stats.corrected++;
		if (mtd_is_eccerr(res))
			mtd->ecc_stats.failed++;
	}
	return res;
}

static int part_read_user_prot_reg(struct mtd_info *mtd, loff_t from,
		size_t len, size_t *retlen, u_char *buf)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_read_user_prot_reg(part->parent, from, len,
						 retlen, buf);
}

static int part_get_user_prot_info(struct mtd_info *mtd, size_t len,
				   size_t *retlen, struct otp_info *buf)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_get_user_prot_info(part->parent, len, retlen,
						 buf);
}

static int part_read_fact_prot_reg(struct mtd_info *mtd, loff_t from,
		size_t len, size_t *retlen, u_char *buf)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_read_fact_prot_reg(part->parent, from, len,
						 retlen, buf);
}

static int part_get_fact_prot_info(struct mtd_info *mtd, size_t len,
				   size_t *retlen, struct otp_info *buf)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_get_fact_prot_info(part->parent, len, retlen,
						 buf);
}

static int part_write(struct mtd_info *mtd, loff_t to, size_t len,
		size_t *retlen, const u_char *buf)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_write(part->parent, to + part->offset, len,
				    retlen, buf);
}

static int part_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
		size_t *retlen, const u_char *buf)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_panic_write(part->parent, to + part->offset, len,
					  retlen, buf);
}

static int part_write_oob(struct mtd_info *mtd, loff_t to,
		struct mtd_oob_ops *ops)
{
	struct mtd_part *part = mtd_to_part(mtd);

	if (to >= mtd->size)
		return -EINVAL;
	if (ops->datbuf && to + ops->len > mtd->size)
		return -EINVAL;
	return part->parent->_write_oob(part->parent, to + part->offset, ops);
}

static int part_write_user_prot_reg(struct mtd_info *mtd, loff_t from,
		size_t len, size_t *retlen, u_char *buf)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_write_user_prot_reg(part->parent, from, len,
						  retlen, buf);
}

static int part_lock_user_prot_reg(struct mtd_info *mtd, loff_t from,
		size_t len)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_lock_user_prot_reg(part->parent, from, len);
}

static int part_writev(struct mtd_info *mtd, const struct kvec *vecs,
		unsigned long count, loff_t to, size_t *retlen)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_writev(part->parent, vecs, count,
				     to + part->offset, retlen);
}

static int part_erase(struct mtd_info *mtd, struct erase_info *instr)
{
	struct mtd_part *part = mtd_to_part(mtd);
	int ret;

	instr->addr += part->offset;
	ret = part->parent->_erase(part->parent, instr);
	if (ret) {
		if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
			instr->fail_addr -= part->offset;
		instr->addr -= part->offset;
	}
	return ret;
}

void mtd_erase_callback(struct erase_info *instr)
{
	if (instr->mtd->_erase == part_erase) {
		struct mtd_part *part = mtd_to_part(instr->mtd);

		if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
			instr->fail_addr -= part->offset;
		instr->addr -= part->offset;
	}
	if (instr->callback)
		instr->callback(instr);
}
EXPORT_SYMBOL_GPL(mtd_erase_callback);

static int part_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_lock(part->parent, ofs + part->offset, len);
}

static int part_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_unlock(part->parent, ofs + part->offset, len);
}

static int part_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_is_locked(part->parent, ofs + part->offset, len);
}

static void part_sync(struct mtd_info *mtd)
{
	struct mtd_part *part = mtd_to_part(mtd);
	part->parent->_sync(part->parent);
}

static int part_suspend(struct mtd_info *mtd)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_suspend(part->parent);
}

static void part_resume(struct mtd_info *mtd)
{
	struct mtd_part *part = mtd_to_part(mtd);
	part->parent->_resume(part->parent);
}

static int part_block_isreserved(struct mtd_info *mtd, loff_t ofs)
{
	struct mtd_part *part = mtd_to_part(mtd);
	ofs += part->offset;
	return part->parent->_block_isreserved(part->parent, ofs);
}

static int part_block_isbad(struct mtd_info *mtd, loff_t ofs)
{
	struct mtd_part *part = mtd_to_part(mtd);
	ofs += part->offset;
	return part->parent->_block_isbad(part->parent, ofs);
}

static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
{
	struct mtd_part *part = mtd_to_part(mtd);
	int res;

	ofs += part->offset;
	res = part->parent->_block_markbad(part->parent, ofs);
	if (!res)
		mtd->ecc_stats.badblocks++;
	return res;
}

static int part_get_device(struct mtd_info *mtd)
{
	struct mtd_part *part = mtd_to_part(mtd);
	return part->parent->_get_device(part->parent);
}

static void part_put_device(struct mtd_info *mtd)
{
	struct mtd_part *part = mtd_to_part(mtd);
	part->parent->_put_device(part->parent);
}

static int part_ooblayout_ecc(struct mtd_info *mtd, int section,
			      struct mtd_oob_region *oobregion)
{
	struct mtd_part *part = mtd_to_part(mtd);

	return mtd_ooblayout_ecc(part->parent, section, oobregion);
}

static int part_ooblayout_free(struct mtd_info *mtd, int section,
			       struct mtd_oob_region *oobregion)
{
	struct mtd_part *part = mtd_to_part(mtd);

	return mtd_ooblayout_free(part->parent, section, oobregion);
}

static const struct mtd_ooblayout_ops part_ooblayout_ops = {
	.ecc = part_ooblayout_ecc,
	.free = part_ooblayout_free,
};

static int part_max_bad_blocks(struct mtd_info *mtd, loff_t ofs, size_t len)
{
	struct mtd_part *part = mtd_to_part(mtd);

	return part->parent->_max_bad_blocks(part->parent,
					     ofs + part->offset, len);
}

static inline void free_partition(struct mtd_part *p)
{
	kfree(p->mtd.name);
	kfree(p);
}

/**
 * mtd_parse_part - parse MTD partition looking for subpartitions
 *
 * @slave: part that is supposed to be a container and should be parsed
 * @types: NULL-terminated array with names of partition parsers to try
 *
 * Some partitions are kind of containers with extra subpartitions (volumes).
 * There can be various formats of such containers. This function tries to use
 * specified parsers to analyze given partition and registers found
 * subpartitions on success.
 */
static int mtd_parse_part(struct mtd_part *slave, const char *const *types)
{
	struct mtd_partitions parsed;
	int err;

	err = parse_mtd_partitions(&slave->mtd, types, &parsed, NULL);
	if (err)
		return err;
	else if (!parsed.nr_parts)
		return -ENOENT;

	err = add_mtd_partitions(&slave->mtd, parsed.parts, parsed.nr_parts);

	mtd_part_parser_cleanup(&parsed);

	return err;
}

static struct mtd_part *allocate_partition(struct mtd_info *parent,
			const struct mtd_partition *part, int partno,
			uint64_t cur_offset)
{
	int wr_alignment = (parent->flags & MTD_NO_ERASE) ? parent->writesize :
							    parent->erasesize;
	struct mtd_part *slave;
	u32 remainder;
	char *name;
	u64 tmp;

	/* allocate the partition structure */
	slave = kzalloc(sizeof(*slave), GFP_KERNEL);
	name = kstrdup(part->name, GFP_KERNEL);
	if (!name || !slave) {
		printk(KERN_ERR"memory allocation error while creating partitions for \"%s\"\n",
		       parent->name);
		kfree(name);
		kfree(slave);
		return ERR_PTR(-ENOMEM);
	}

	/* set up the MTD object for this partition */
	slave->mtd.type = parent->type;
	slave->mtd.flags = parent->flags & ~part->mask_flags;
	slave->mtd.size = part->size;
	slave->mtd.writesize = parent->writesize;
	slave->mtd.writebufsize = parent->writebufsize;
	slave->mtd.oobsize = parent->oobsize;
	slave->mtd.oobavail = parent->oobavail;
	slave->mtd.subpage_sft = parent->subpage_sft;
	slave->mtd.pairing = parent->pairing;

	slave->mtd.name = name;
	slave->mtd.owner = parent->owner;

	/* NOTE: Historically, we didn't arrange MTDs as a tree out of
	 * concern for showing the same data in multiple partitions.
	 * However, it is very useful to have the master node present,
	 * so the MTD_PARTITIONED_MASTER option allows that. The master
	 * will have device nodes etc only if this is set, so make the
	 * parent conditional on that option. Note, this is a way to
	 * distinguish between the master and the partition in sysfs.
	 */
	slave->mtd.dev.parent = IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER) || mtd_is_partition(parent) ?
				&parent->dev :
				parent->dev.parent;
	slave->mtd.dev.of_node = part->of_node;

	slave->mtd._read = part_read;
	slave->mtd._write = part_write;

	if (parent->_panic_write)
		slave->mtd._panic_write = part_panic_write;

	if (parent->_point && parent->_unpoint) {
		slave->mtd._point = part_point;
		slave->mtd._unpoint = part_unpoint;
	}

	if (parent->_get_unmapped_area)
		slave->mtd._get_unmapped_area = part_get_unmapped_area;
	if (parent->_read_oob)
		slave->mtd._read_oob = part_read_oob;
	if (parent->_write_oob)
		slave->mtd._write_oob = part_write_oob;
	if (parent->_read_user_prot_reg)
		slave->mtd._read_user_prot_reg = part_read_user_prot_reg;
	if (parent->_read_fact_prot_reg)
		slave->mtd._read_fact_prot_reg = part_read_fact_prot_reg;
	if (parent->_write_user_prot_reg)
		slave->mtd._write_user_prot_reg = part_write_user_prot_reg;
	if (parent->_lock_user_prot_reg)
		slave->mtd._lock_user_prot_reg = part_lock_user_prot_reg;
	if (parent->_get_user_prot_info)
		slave->mtd._get_user_prot_info = part_get_user_prot_info;
	if (parent->_get_fact_prot_info)
		slave->mtd._get_fact_prot_info = part_get_fact_prot_info;
	if (parent->_sync)
		slave->mtd._sync = part_sync;
	if (!partno && !parent->dev.class && parent->_suspend &&
	    parent->_resume) {
		slave->mtd._suspend = part_suspend;
		slave->mtd._resume = part_resume;
	}
	if (parent->_writev)
		slave->mtd._writev = part_writev;
	if (parent->_lock)
		slave->mtd._lock = part_lock;
	if (parent->_unlock)
		slave->mtd._unlock = part_unlock;
	if (parent->_is_locked)
		slave->mtd._is_locked = part_is_locked;
	if (parent->_block_isreserved)
		slave->mtd._block_isreserved = part_block_isreserved;
	if (parent->_block_isbad)
		slave->mtd._block_isbad = part_block_isbad;
	if (parent->_block_markbad)
		slave->mtd._block_markbad = part_block_markbad;
	if (parent->_max_bad_blocks)
		slave->mtd._max_bad_blocks = part_max_bad_blocks;

	if (parent->_get_device)
		slave->mtd._get_device = part_get_device;
	if (parent->_put_device)
		slave->mtd._put_device = part_put_device;

	slave->mtd._erase = part_erase;
	slave->parent = parent;
	slave->offset = part->offset;

	if (slave->offset == MTDPART_OFS_APPEND)
		slave->offset = cur_offset;
	if (slave->offset == MTDPART_OFS_NXTBLK) {
		tmp = cur_offset;
		slave->offset = cur_offset;
		remainder = do_div(tmp, wr_alignment);
		if (remainder) {
			slave->offset += wr_alignment - remainder;
			printk(KERN_NOTICE "Moving partition %d: "
			       "0x%012llx -> 0x%012llx\n", partno,
			       (unsigned long long)cur_offset, (unsigned long long)slave->offset);
		}
	}
	if (slave->offset == MTDPART_OFS_RETAIN) {
		slave->offset = cur_offset;
		if (parent->size - slave->offset >= slave->mtd.size) {
			slave->mtd.size = parent->size - slave->offset
							- slave->mtd.size;
		} else {
			printk(KERN_ERR "mtd partition \"%s\" doesn't have enough space: %#llx < %#llx, disabled\n",
				part->name, parent->size - slave->offset,
				slave->mtd.size);
			/* register to preserve ordering */
			goto out_register;
		}
	}
	if (slave->mtd.size == MTDPART_SIZ_FULL)
		slave->mtd.size = parent->size - slave->offset;

	printk(KERN_NOTICE "0x%012llx-0x%012llx : \"%s\"\n", (unsigned long long)slave->offset,
		(unsigned long long)(slave->offset + slave->mtd.size), slave->mtd.name);

	/* let's do some sanity checks */
	if (slave->offset >= parent->size) {
		/* let's register it anyway to preserve ordering */
		slave->offset = 0;
		slave->mtd.size = 0;
		printk(KERN_ERR"mtd: partition \"%s\" is out of reach -- disabled\n",
			part->name);
		goto out_register;
	}
	if (slave->offset + slave->mtd.size > parent->size) {
		slave->mtd.size = parent->size - slave->offset;
		printk(KERN_WARNING"mtd: partition \"%s\" extends beyond the end of device \"%s\" -- size truncated to %#llx\n",
			part->name, parent->name, (unsigned long long)slave->mtd.size);
	}
	if (parent->numeraseregions > 1) {
		/* Deal with variable erase size stuff */
		int i, max = parent->numeraseregions;
		u64 end = slave->offset + slave->mtd.size;
		struct mtd_erase_region_info *regions = parent->eraseregions;

		/* Find the first erase regions which is part of this
		 * partition. */
		for (i = 0; i < max && regions[i].offset <= slave->offset; i++)
			;
		/* The loop searched for the region _behind_ the first one */
		if (i > 0)
			i--;

		/* Pick biggest erasesize */
		for (; i < max && regions[i].offset < end; i++) {
			if (slave->mtd.erasesize < regions[i].erasesize) {
				slave->mtd.erasesize = regions[i].erasesize;
			}
		}
		BUG_ON(slave->mtd.erasesize == 0);
	} else {
		/* Single erase size */
		slave->mtd.erasesize = parent->erasesize;
	}

	/*
	 * Slave erasesize might differ from the master one if the master
	 * exposes several regions with different erasesize. Adjust
	 * wr_alignment accordingly.
	 */
	if (!(slave->mtd.flags & MTD_NO_ERASE))
		wr_alignment = slave->mtd.erasesize;

	tmp = slave->offset;
	remainder = do_div(tmp, wr_alignment);
	if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
		/* Doesn't start on a boundary of major erase size */
		/* FIXME: Let it be writable if it is on a boundary of
		 * _minor_ erase size though */
		slave->mtd.flags &= ~MTD_WRITEABLE;
		printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase/write block boundary -- force read-only\n",
			part->name);
	}

	tmp = slave->mtd.size;
	remainder = do_div(tmp, wr_alignment);
	if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
		slave->mtd.flags &= ~MTD_WRITEABLE;
		printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase/write block -- force read-only\n",
			part->name);
	}

	mtd_set_ooblayout(&slave->mtd, &part_ooblayout_ops);
	slave->mtd.ecc_step_size = parent->ecc_step_size;
	slave->mtd.ecc_strength = parent->ecc_strength;
	slave->mtd.bitflip_threshold = parent->bitflip_threshold;

	if (parent->_block_isbad) {
		uint64_t offs = 0;

		while (offs < slave->mtd.size) {
			if (mtd_block_isreserved(parent, offs + slave->offset))
				slave->mtd.ecc_stats.bbtblocks++;
			else if (mtd_block_isbad(parent, offs + slave->offset))
				slave->mtd.ecc_stats.badblocks++;
			offs += slave->mtd.erasesize;
		}
	}

out_register:
	return slave;
}

static ssize_t mtd_partition_offset_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_get_drvdata(dev);
	struct mtd_part *part = mtd_to_part(mtd);
	return snprintf(buf, PAGE_SIZE, "%lld\n", part->offset);
}

static DEVICE_ATTR(offset, S_IRUGO, mtd_partition_offset_show, NULL);

static const struct attribute *mtd_partition_attrs[] = {
	&dev_attr_offset.attr,
	NULL
};

static int mtd_add_partition_attrs(struct mtd_part *new)
{
	int ret = sysfs_create_files(&new->mtd.dev.kobj, mtd_partition_attrs);
	if (ret)
		printk(KERN_WARNING
		       "mtd: failed to create partition attrs, err=%d\n", ret);
	return ret;
}

int mtd_add_partition(struct mtd_info *parent, const char *name,
		      long long offset, long long length)
{
	struct mtd_partition part;
	struct mtd_part *new;
	int ret = 0;

	/* the direct offset is expected */
	if (offset == MTDPART_OFS_APPEND ||
	    offset == MTDPART_OFS_NXTBLK)
		return -EINVAL;

	if (length == MTDPART_SIZ_FULL)
		length = parent->size - offset;

	if (length <= 0)
		return -EINVAL;

	memset(&part, 0, sizeof(part));
	part.name = name;
	part.size = length;
	part.offset = offset;

	new = allocate_partition(parent, &part, -1, offset);
	if (IS_ERR(new))
		return PTR_ERR(new);

	mutex_lock(&mtd_partitions_mutex);
	list_add(&new->list, &mtd_partitions);
	mutex_unlock(&mtd_partitions_mutex);

	add_mtd_device(&new->mtd);

	mtd_add_partition_attrs(new);

	return ret;
}
EXPORT_SYMBOL_GPL(mtd_add_partition);

/**
 * __mtd_del_partition - delete MTD partition
 *
 * @priv: internal MTD struct for partition to be deleted
 *
 * This function must be called with the partitions mutex locked.
 */
static int __mtd_del_partition(struct mtd_part *priv)
{
	struct mtd_part *child, *next;
	int err;

	list_for_each_entry_safe(child, next, &mtd_partitions, list) {
		if (child->parent == &priv->mtd) {
			err = __mtd_del_partition(child);
			if (err)
				return err;
		}
	}

	sysfs_remove_files(&priv->mtd.dev.kobj, mtd_partition_attrs);

	err = del_mtd_device(&priv->mtd);
	if (err)
		return err;

	list_del(&priv->list);
	free_partition(priv);

	return 0;
}

/*
 * This function unregisters and destroy all slave MTD objects which are
 * attached to the given MTD object.
 */
int del_mtd_partitions(struct mtd_info *mtd)
{
	struct mtd_part *slave, *next;
	int ret, err = 0;

	mutex_lock(&mtd_partitions_mutex);
	list_for_each_entry_safe(slave, next, &mtd_partitions, list)
		if (slave->parent == mtd) {
			ret = __mtd_del_partition(slave);
			if (ret < 0)
				err = ret;
		}
	mutex_unlock(&mtd_partitions_mutex);

	return err;
}

int mtd_del_partition(struct mtd_info *mtd, int partno)
{
	struct mtd_part *slave, *next;
	int ret = -EINVAL;

	mutex_lock(&mtd_partitions_mutex);
	list_for_each_entry_safe(slave, next, &mtd_partitions, list)
		if ((slave->parent == mtd) &&
		    (slave->mtd.index == partno)) {
			ret = __mtd_del_partition(slave);
			break;
		}
	mutex_unlock(&mtd_partitions_mutex);

	return ret;
}
EXPORT_SYMBOL_GPL(mtd_del_partition);

/*
 * This function, given a master MTD object and a partition table, creates
 * and registers slave MTD objects which are bound to the master according to
 * the partition definitions.
 *
 * For historical reasons, this function's caller only registers the master
 * if the MTD_PARTITIONED_MASTER config option is set.
 */

int add_mtd_partitions(struct mtd_info *master,
		       const struct mtd_partition *parts,
		       int nbparts)
{
	struct mtd_part *slave;
	uint64_t cur_offset = 0;
	int i;

	printk(KERN_NOTICE "Creating %d MTD partitions on \"%s\":\n", nbparts, master->name);

	for (i = 0; i < nbparts; i++) {
		slave = allocate_partition(master, parts + i, i, cur_offset);
		if (IS_ERR(slave)) {
			del_mtd_partitions(master);
			return PTR_ERR(slave);
		}

		mutex_lock(&mtd_partitions_mutex);
		list_add(&slave->list, &mtd_partitions);
		mutex_unlock(&mtd_partitions_mutex);

		add_mtd_device(&slave->mtd);
		mtd_add_partition_attrs(slave);
		if (parts[i].types)
			mtd_parse_part(slave, parts[i].types);

		cur_offset = slave->offset + slave->mtd.size;
	}

	return 0;
}

static DEFINE_SPINLOCK(part_parser_lock);
static LIST_HEAD(part_parsers);

static struct mtd_part_parser *mtd_part_parser_get(const char *name)
{
	struct mtd_part_parser *p, *ret = NULL;

	spin_lock(&part_parser_lock);

	list_for_each_entry(p, &part_parsers, list)
		if (!strcmp(p->name, name) && try_module_get(p->owner)) {
			ret = p;
			break;
		}

	spin_unlock(&part_parser_lock);

	return ret;
}

static inline void mtd_part_parser_put(const struct mtd_part_parser *p)
{
	module_put(p->owner);
}

/*
 * Many partition parsers just expected the core to kfree() all their data in
 * one chunk. Do that by default.
 */
static void mtd_part_parser_cleanup_default(const struct mtd_partition *pparts,
					    int nr_parts)
{
	kfree(pparts);
}

int __register_mtd_parser(struct mtd_part_parser *p, struct module *owner)
{
	p->owner = owner;

	if (!p->cleanup)
		p->cleanup = &mtd_part_parser_cleanup_default;

	spin_lock(&part_parser_lock);
	list_add(&p->list, &part_parsers);
	spin_unlock(&part_parser_lock);

	return 0;
}
EXPORT_SYMBOL_GPL(__register_mtd_parser);

void deregister_mtd_parser(struct mtd_part_parser *p)
{
	spin_lock(&part_parser_lock);
	list_del(&p->list);
	spin_unlock(&part_parser_lock);
}
EXPORT_SYMBOL_GPL(deregister_mtd_parser);

/*
 * Do not forget to update 'parse_mtd_partitions()' kerneldoc comment if you
 * are changing this array!
 */
static const char * const default_mtd_part_types[] = {
	"cmdlinepart",
	"ofpart",
	NULL
};

static int mtd_part_do_parse(struct mtd_part_parser *parser,
			     struct mtd_info *master,
			     struct mtd_partitions *pparts,
			     struct mtd_part_parser_data *data)
{
	int ret;

	ret = (*parser->parse_fn)(master, &pparts->parts, data);
	pr_debug("%s: parser %s: %i\n", master->name, parser->name, ret);
	if (ret <= 0)
		return ret;

	pr_notice("%d %s partitions found on MTD device %s\n", ret,
		  parser->name, master->name);

	pparts->nr_parts = ret;
	pparts->parser = parser;

	return ret;
}

/**
 * parse_mtd_partitions - parse MTD partitions
 * @master: the master partition (describes whole MTD device)
 * @types: names of partition parsers to try or %NULL
 * @pparts: info about partitions found is returned here
 * @data: MTD partition parser-specific data
 *
 * This function tries to find partition on MTD device @master. It uses MTD
 * partition parsers, specified in @types. However, if @types is %NULL, then
 * the default list of parsers is used. The default list contains only the
 * "cmdlinepart" and "ofpart" parsers ATM.
 * Note: If there are more then one parser in @types, the kernel only takes the
 * partitions parsed out by the first parser.
 *
 * This function may return:
 * o a negative error code in case of failure
 * o zero otherwise, and @pparts will describe the partitions, number of
 *   partitions, and the parser which parsed them. Caller must release
 *   resources with mtd_part_parser_cleanup() when finished with the returned
 *   data.
 */
int parse_mtd_partitions(struct mtd_info *master, const char *const *types,
			 struct mtd_partitions *pparts,
			 struct mtd_part_parser_data *data)
{
	struct mtd_part_parser *parser;
	int ret, err = 0;

	if (!types)
		types = default_mtd_part_types;

	for ( ; *types; types++) {
		pr_debug("%s: parsing partitions %s\n", master->name, *types);
		parser = mtd_part_parser_get(*types);
		if (!parser && !request_module("%s", *types))
			parser = mtd_part_parser_get(*types);
		pr_debug("%s: got parser %s\n", master->name,
			 parser ? parser->name : NULL);
		if (!parser)
			continue;
		ret = mtd_part_do_parse(parser, master, pparts, data);
		/* Found partitions! */
		if (ret > 0)
			return 0;
		mtd_part_parser_put(parser);
		/*
		 * Stash the first error we see; only report it if no parser
		 * succeeds
		 */
		if (ret < 0 && !err)
			err = ret;
	}
	return err;
}

void mtd_part_parser_cleanup(struct mtd_partitions *parts)
{
	const struct mtd_part_parser *parser;

	if (!parts)
		return;

	parser = parts->parser;
	if (parser) {
		if (parser->cleanup)
			parser->cleanup(parts->parts, parts->nr_parts);

		mtd_part_parser_put(parser);
	}
}

int mtd_is_partition(const struct mtd_info *mtd)
{
	struct mtd_part *part;
	int ispart = 0;

	mutex_lock(&mtd_partitions_mutex);
	list_for_each_entry(part, &mtd_partitions, list)
		if (&part->mtd == mtd) {
			ispart = 1;
			break;
		}
	mutex_unlock(&mtd_partitions_mutex);

	return ispart;
}
EXPORT_SYMBOL_GPL(mtd_is_partition);

/* Returns the size of the entire flash chip */
uint64_t mtd_get_device_size(const struct mtd_info *mtd)
{
	if (!mtd_is_partition(mtd))
		return mtd->size;

	return mtd_get_device_size(mtd_to_part(mtd)->parent);
}
EXPORT_SYMBOL_GPL(mtd_get_device_size);