drivers/mtd/mtdpart.c

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