drivers/mtd/mtdconcat.c

   1 /*
   2  * MTD device concatenation layer
   3  *
   4  * Copyright © 2002 Robert Kaiser <rkaiser@sysgo.de>
   5  * Copyright © 2002-2010 David Woodhouse <dwmw2@infradead.org>
   6  *
   7  * NAND support by Christian Gan <cgan@iders.ca>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  22  *
  23  */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/module.h>
  27 #include <linux/slab.h>
  28 #include <linux/sched.h>
  29 #include <linux/types.h>
  30 #include <linux/backing-dev.h>
  31
  32 #include <linux/mtd/mtd.h>
  33 #include <linux/mtd/concat.h>
  34
  35 #include <asm/div64.h>
  36
  37 /*
  38  * Our storage structure:
  39  * Subdev points to an array of pointers to struct mtd_info objects
  40  * which is allocated along with this structure
  41  *
  42  */
  43 struct mtd_concat {
  44         struct mtd_info mtd;
  45         int num_subdev;
  46         struct mtd_info **subdev;
  47 };
  48
  49 /*
  50  * how to calculate the size required for the above structure,
  51  * including the pointer array subdev points to:
  52  */
  53 #define SIZEOF_STRUCT_MTD_CONCAT(num_subdev)    \
  54         ((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *)))
  55
  56 /*
  57  * Given a pointer to the MTD object in the mtd_concat structure,
  58  * we can retrieve the pointer to that structure with this macro.
  59  */
  60 #define CONCAT(x)  ((struct mtd_concat *)(x))
  61
  62 /*
  63  * MTD methods which look up the relevant subdevice, translate the
  64  * effective address and pass through to the subdevice.
  65  */
  66
  67 static int
  68 concat_read(struct mtd_info *mtd, loff_t from, size_t len,
  69             size_t * retlen, u_char * buf)
  70 {
  71         struct mtd_concat *concat = CONCAT(mtd);
  72         int ret = 0, err;
  73         int i;
  74
  75         *retlen = 0;
  76
  77         for (i = 0; i < concat->num_subdev; i++) {
  78                 struct mtd_info *subdev = concat->subdev[i];
  79                 size_t size, retsize;
  80
  81                 if (from >= subdev->size) {
  82                         /* Not destined for this subdev */
  83                         size = 0;
  84                         from -= subdev->size;
  85                         continue;
  86                 }
  87                 if (from + len > subdev->size)
  88                         /* First part goes into this subdev */
  89                         size = subdev->size - from;
  90                 else
  91                         /* Entire transaction goes into this subdev */
  92                         size = len;
  93
  94                 err = mtd_read(subdev, from, size, &retsize, buf);
  95
  96                 /* Save information about bitflips! */
  97                 if (unlikely(err)) {
  98                         if (mtd_is_eccerr(err)) {
  99                                 mtd->ecc_stats.failed++;
 100                                 ret = err;
 101                         } else if (mtd_is_bitflip(err)) {
 102                                 mtd->ecc_stats.corrected++;
 103                                 /* Do not overwrite -EBADMSG !! */
 104                                 if (!ret)
 105                                         ret = err;
 106                         } else
 107                                 return err;
 108                 }
 109
 110                 *retlen += retsize;
 111                 len -= size;
 112                 if (len == 0)
 113                         return ret;
 114
 115                 buf += size;
 116                 from = 0;
 117         }
 118         return -EINVAL;
 119 }
 120
 121 static int
 122 concat_write(struct mtd_info *mtd, loff_t to, size_t len,
 123              size_t * retlen, const u_char * buf)
 124 {
 125         struct mtd_concat *concat = CONCAT(mtd);
 126         int err = -EINVAL;
 127         int i;
 128
 129         if (!(mtd->flags & MTD_WRITEABLE))
 130                 return -EROFS;
 131
 132         *retlen = 0;
 133
 134         for (i = 0; i < concat->num_subdev; i++) {
 135                 struct mtd_info *subdev = concat->subdev[i];
 136                 size_t size, retsize;
 137
 138                 if (to >= subdev->size) {
 139                         size = 0;
 140                         to -= subdev->size;
 141                         continue;
 142                 }
 143                 if (to + len > subdev->size)
 144                         size = subdev->size - to;
 145                 else
 146                         size = len;
 147
 148                 if (!(subdev->flags & MTD_WRITEABLE))
 149                         err = -EROFS;
 150                 else
 151                         err = mtd_write(subdev, to, size, &retsize, buf);
 152
 153                 if (err)
 154                         break;
 155
 156                 *retlen += retsize;
 157                 len -= size;
 158                 if (len == 0)
 159                         break;
 160
 161                 err = -EINVAL;
 162                 buf += size;
 163                 to = 0;
 164         }
 165         return err;
 166 }
 167
 168 static int
 169 concat_writev(struct mtd_info *mtd, const struct kvec *vecs,
 170                 unsigned long count, loff_t to, size_t * retlen)
 171 {
 172         struct mtd_concat *concat = CONCAT(mtd);
 173         struct kvec *vecs_copy;
 174         unsigned long entry_low, entry_high;
 175         size_t total_len = 0;
 176         int i;
 177         int err = -EINVAL;
 178
 179         if (!(mtd->flags & MTD_WRITEABLE))
 180                 return -EROFS;
 181
 182         *retlen = 0;
 183
 184         /* Calculate total length of data */
 185         for (i = 0; i < count; i++)
 186                 total_len += vecs[i].iov_len;
 187
 188         /* Check alignment */
 189         if (mtd->writesize > 1) {
 190                 uint64_t __to = to;
 191                 if (do_div(__to, mtd->writesize) || (total_len % mtd->writesize))
 192                         return -EINVAL;
 193         }
 194
 195         /* make a copy of vecs */
 196         vecs_copy = kmemdup(vecs, sizeof(struct kvec) * count, GFP_KERNEL);
 197         if (!vecs_copy)
 198                 return -ENOMEM;
 199
 200         entry_low = 0;
 201         for (i = 0; i < concat->num_subdev; i++) {
 202                 struct mtd_info *subdev = concat->subdev[i];
 203                 size_t size, wsize, retsize, old_iov_len;
 204
 205                 if (to >= subdev->size) {
 206                         to -= subdev->size;
 207                         continue;
 208                 }
 209
 210                 size = min_t(uint64_t, total_len, subdev->size - to);
 211                 wsize = size; /* store for future use */
 212
 213                 entry_high = entry_low;
 214                 while (entry_high < count) {
 215                         if (size <= vecs_copy[entry_high].iov_len)
 216                                 break;
 217                         size -= vecs_copy[entry_high++].iov_len;
 218                 }
 219
 220                 old_iov_len = vecs_copy[entry_high].iov_len;
 221                 vecs_copy[entry_high].iov_len = size;
 222
 223                 if (!(subdev->flags & MTD_WRITEABLE))
 224                         err = -EROFS;
 225                 else
 226                         err = mtd_writev(subdev, &vecs_copy[entry_low],
 227                                          entry_high - entry_low + 1, to,
 228                                          &retsize);
 229
 230                 vecs_copy[entry_high].iov_len = old_iov_len - size;
 231                 vecs_copy[entry_high].iov_base += size;
 232
 233                 entry_low = entry_high;
 234
 235                 if (err)
 236                         break;
 237
 238                 *retlen += retsize;
 239                 total_len -= wsize;
 240
 241                 if (total_len == 0)
 242                         break;
 243
 244                 err = -EINVAL;
 245                 to = 0;
 246         }
 247
 248         kfree(vecs_copy);
 249         return err;
 250 }
 251
 252 static int
 253 concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
 254 {
 255         struct mtd_concat *concat = CONCAT(mtd);
 256         struct mtd_oob_ops devops = *ops;
 257         int i, err, ret = 0;
 258
 259         ops->retlen = ops->oobretlen = 0;
 260
 261         for (i = 0; i < concat->num_subdev; i++) {
 262                 struct mtd_info *subdev = concat->subdev[i];
 263
 264                 if (from >= subdev->size) {
 265                         from -= subdev->size;
 266                         continue;
 267                 }
 268
 269                 /* partial read ? */
 270                 if (from + devops.len > subdev->size)
 271                         devops.len = subdev->size - from;
 272
 273                 err = mtd_read_oob(subdev, from, &devops);
 274                 ops->retlen += devops.retlen;
 275                 ops->oobretlen += devops.oobretlen;
 276
 277                 /* Save information about bitflips! */
 278                 if (unlikely(err)) {
 279                         if (mtd_is_eccerr(err)) {
 280                                 mtd->ecc_stats.failed++;
 281                                 ret = err;
 282                         } else if (mtd_is_bitflip(err)) {
 283                                 mtd->ecc_stats.corrected++;
 284                                 /* Do not overwrite -EBADMSG !! */
 285                                 if (!ret)
 286                                         ret = err;
 287                         } else
 288                                 return err;
 289                 }
 290
 291                 if (devops.datbuf) {
 292                         devops.len = ops->len - ops->retlen;
 293                         if (!devops.len)
 294                                 return ret;
 295                         devops.datbuf += devops.retlen;
 296                 }
 297                 if (devops.oobbuf) {
 298                         devops.ooblen = ops->ooblen - ops->oobretlen;
 299                         if (!devops.ooblen)
 300                                 return ret;
 301                         devops.oobbuf += ops->oobretlen;
 302                 }
 303
 304                 from = 0;
 305         }
 306         return -EINVAL;
 307 }
 308
 309 static int
 310 concat_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops)
 311 {
 312         struct mtd_concat *concat = CONCAT(mtd);
 313         struct mtd_oob_ops devops = *ops;
 314         int i, err;
 315
 316         if (!(mtd->flags & MTD_WRITEABLE))
 317                 return -EROFS;
 318
 319         ops->retlen = ops->oobretlen = 0;
 320
 321         for (i = 0; i < concat->num_subdev; i++) {
 322                 struct mtd_info *subdev = concat->subdev[i];
 323
 324                 if (to >= subdev->size) {
 325                         to -= subdev->size;
 326                         continue;
 327                 }
 328
 329                 /* partial write ? */
 330                 if (to + devops.len > subdev->size)
 331                         devops.len = subdev->size - to;
 332
 333                 err = mtd_write_oob(subdev, to, &devops);
 334                 ops->retlen += devops.oobretlen;
 335                 if (err)
 336                         return err;
 337
 338                 if (devops.datbuf) {
 339                         devops.len = ops->len - ops->retlen;
 340                         if (!devops.len)
 341                                 return 0;
 342                         devops.datbuf += devops.retlen;
 343                 }
 344                 if (devops.oobbuf) {
 345                         devops.ooblen = ops->ooblen - ops->oobretlen;
 346                         if (!devops.ooblen)
 347                                 return 0;
 348                         devops.oobbuf += devops.oobretlen;
 349                 }
 350                 to = 0;
 351         }
 352         return -EINVAL;
 353 }
 354
 355 static void concat_erase_callback(struct erase_info *instr)
 356 {
 357         wake_up((wait_queue_head_t *) instr->priv);
 358 }
 359
 360 static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase)
 361 {
 362         int err;
 363         wait_queue_head_t waitq;
 364         DECLARE_WAITQUEUE(wait, current);
 365
 366         /*
 367          * This code was stol^H^H^H^Hinspired by mtdchar.c
 368          */
 369         init_waitqueue_head(&waitq);
 370
 371         erase->mtd = mtd;
 372         erase->callback = concat_erase_callback;
 373         erase->priv = (unsigned long) &waitq;
 374
 375         /*
 376          * FIXME: Allow INTERRUPTIBLE. Which means
 377          * not having the wait_queue head on the stack.
 378          */
 379         err = mtd_erase(mtd, erase);
 380         if (!err) {
 381                 set_current_state(TASK_UNINTERRUPTIBLE);
 382                 add_wait_queue(&waitq, &wait);
 383                 if (erase->state != MTD_ERASE_DONE
 384                     && erase->state != MTD_ERASE_FAILED)
 385                         schedule();
 386                 remove_wait_queue(&waitq, &wait);
 387                 set_current_state(TASK_RUNNING);
 388
 389                 err = (erase->state == MTD_ERASE_FAILED) ? -EIO : 0;
 390         }
 391         return err;
 392 }
 393
 394 static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
 395 {
 396         struct mtd_concat *concat = CONCAT(mtd);
 397         struct mtd_info *subdev;
 398         int i, err;
 399         uint64_t length, offset = 0;
 400         struct erase_info *erase;
 401
 402         if (!(mtd->flags & MTD_WRITEABLE))
 403                 return -EROFS;
 404
 405         /*
 406          * Check for proper erase block alignment of the to-be-erased area.
 407          * It is easier to do this based on the super device's erase
 408          * region info rather than looking at each particular sub-device
 409          * in turn.
 410          */
 411         if (!concat->mtd.numeraseregions) {
 412                 /* the easy case: device has uniform erase block size */
 413                 if (instr->addr & (concat->mtd.erasesize - 1))
 414                         return -EINVAL;
 415                 if (instr->len & (concat->mtd.erasesize - 1))
 416                         return -EINVAL;
 417         } else {
 418                 /* device has variable erase size */
 419                 struct mtd_erase_region_info *erase_regions =
 420                     concat->mtd.eraseregions;
 421
 422                 /*
 423                  * Find the erase region where the to-be-erased area begins:
 424                  */
 425                 for (i = 0; i < concat->mtd.numeraseregions &&
 426                      instr->addr >= erase_regions[i].offset; i++) ;
 427                 --i;
 428
 429                 /*
 430                  * Now erase_regions[i] is the region in which the
 431                  * to-be-erased area begins. Verify that the starting
 432                  * offset is aligned to this region's erase size:
 433                  */
 434                 if (i < 0 || instr->addr & (erase_regions[i].erasesize - 1))
 435                         return -EINVAL;
 436
 437                 /*
 438                  * now find the erase region where the to-be-erased area ends:
 439                  */
 440                 for (; i < concat->mtd.numeraseregions &&
 441                      (instr->addr + instr->len) >= erase_regions[i].offset;
 442                      ++i) ;
 443                 --i;
 444                 /*
 445                  * check if the ending offset is aligned to this region's erase size
 446                  */
 447                 if (i < 0 || ((instr->addr + instr->len) &
 448                                         (erase_regions[i].erasesize - 1)))
 449                         return -EINVAL;
 450         }
 451
 452         instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
 453
 454         /* make a local copy of instr to avoid modifying the caller's struct */
 455         erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
 456
 457         if (!erase)
 458                 return -ENOMEM;
 459
 460         *erase = *instr;
 461         length = instr->len;
 462
 463         /*
 464          * find the subdevice where the to-be-erased area begins, adjust
 465          * starting offset to be relative to the subdevice start
 466          */
 467         for (i = 0; i < concat->num_subdev; i++) {
 468                 subdev = concat->subdev[i];
 469                 if (subdev->size <= erase->addr) {
 470                         erase->addr -= subdev->size;
 471                         offset += subdev->size;
 472                 } else {
 473                         break;
 474                 }
 475         }
 476
 477         /* must never happen since size limit has been verified above */
 478         BUG_ON(i >= concat->num_subdev);
 479
 480         /* now do the erase: */
 481         err = 0;
 482         for (; length > 0; i++) {
 483                 /* loop for all subdevices affected by this request */
 484                 subdev = concat->subdev[i];     /* get current subdevice */
 485
 486                 /* limit length to subdevice's size: */
 487                 if (erase->addr + length > subdev->size)
 488                         erase->len = subdev->size - erase->addr;
 489                 else
 490                         erase->len = length;
 491
 492                 if (!(subdev->flags & MTD_WRITEABLE)) {
 493                         err = -EROFS;
 494                         break;
 495                 }
 496                 length -= erase->len;
 497                 if ((err = concat_dev_erase(subdev, erase))) {
 498                         /* sanity check: should never happen since
 499                          * block alignment has been checked above */
 500                         BUG_ON(err == -EINVAL);
 501                         if (erase->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
 502                                 instr->fail_addr = erase->fail_addr + offset;
 503                         break;
 504                 }
 505                 /*
 506                  * erase->addr specifies the offset of the area to be
 507                  * erased *within the current subdevice*. It can be
 508                  * non-zero only the first time through this loop, i.e.
 509                  * for the first subdevice where blocks need to be erased.
 510                  * All the following erases must begin at the start of the
 511                  * current subdevice, i.e. at offset zero.
 512                  */
 513                 erase->addr = 0;
 514                 offset += subdev->size;
 515         }
 516         instr->state = erase->state;
 517         kfree(erase);
 518         if (err)
 519                 return err;
 520
 521         if (instr->callback)
 522                 instr->callback(instr);
 523         return 0;
 524 }
 525
 526 static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 527 {
 528         struct mtd_concat *concat = CONCAT(mtd);
 529         int i, err = -EINVAL;
 530
 531         for (i = 0; i < concat->num_subdev; i++) {
 532                 struct mtd_info *subdev = concat->subdev[i];
 533                 uint64_t size;
 534
 535                 if (ofs >= subdev->size) {
 536                         size = 0;
 537                         ofs -= subdev->size;
 538                         continue;
 539                 }
 540                 if (ofs + len > subdev->size)
 541                         size = subdev->size - ofs;
 542                 else
 543                         size = len;
 544
 545                 err = mtd_lock(subdev, ofs, size);
 546                 if (err)
 547                         break;
 548
 549                 len -= size;
 550                 if (len == 0)
 551                         break;
 552
 553                 err = -EINVAL;
 554                 ofs = 0;
 555         }
 556
 557         return err;
 558 }
 559
 560 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 561 {
 562         struct mtd_concat *concat = CONCAT(mtd);
 563         int i, err = 0;
 564
 565         for (i = 0; i < concat->num_subdev; i++) {
 566                 struct mtd_info *subdev = concat->subdev[i];
 567                 uint64_t size;
 568
 569                 if (ofs >= subdev->size) {
 570                         size = 0;
 571                         ofs -= subdev->size;
 572                         continue;
 573                 }
 574                 if (ofs + len > subdev->size)
 575                         size = subdev->size - ofs;
 576                 else
 577                         size = len;
 578
 579                 err = mtd_unlock(subdev, ofs, size);
 580                 if (err)
 581                         break;
 582
 583                 len -= size;
 584                 if (len == 0)
 585                         break;
 586
 587                 err = -EINVAL;
 588                 ofs = 0;
 589         }
 590
 591         return err;
 592 }
 593
 594 static void concat_sync(struct mtd_info *mtd)
 595 {
 596         struct mtd_concat *concat = CONCAT(mtd);
 597         int i;
 598
 599         for (i = 0; i < concat->num_subdev; i++) {
 600                 struct mtd_info *subdev = concat->subdev[i];
 601                 mtd_sync(subdev);
 602         }
 603 }
 604
 605 static int concat_suspend(struct mtd_info *mtd)
 606 {
 607         struct mtd_concat *concat = CONCAT(mtd);
 608         int i, rc = 0;
 609
 610         for (i = 0; i < concat->num_subdev; i++) {
 611                 struct mtd_info *subdev = concat->subdev[i];
 612                 if ((rc = mtd_suspend(subdev)) < 0)
 613                         return rc;
 614         }
 615         return rc;
 616 }
 617
 618 static void concat_resume(struct mtd_info *mtd)
 619 {
 620         struct mtd_concat *concat = CONCAT(mtd);
 621         int i;
 622
 623         for (i = 0; i < concat->num_subdev; i++) {
 624                 struct mtd_info *subdev = concat->subdev[i];
 625                 mtd_resume(subdev);
 626         }
 627 }
 628
 629 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
 630 {
 631         struct mtd_concat *concat = CONCAT(mtd);
 632         int i, res = 0;
 633
 634         if (!mtd_can_have_bb(concat->subdev[0]))
 635                 return res;
 636
 637         for (i = 0; i < concat->num_subdev; i++) {
 638                 struct mtd_info *subdev = concat->subdev[i];
 639
 640                 if (ofs >= subdev->size) {
 641                         ofs -= subdev->size;
 642                         continue;
 643                 }
 644
 645                 res = mtd_block_isbad(subdev, ofs);
 646                 break;
 647         }
 648
 649         return res;
 650 }
 651
 652 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
 653 {
 654         struct mtd_concat *concat = CONCAT(mtd);
 655         int i, err = -EINVAL;
 656
 657         for (i = 0; i < concat->num_subdev; i++) {
 658                 struct mtd_info *subdev = concat->subdev[i];
 659
 660                 if (ofs >= subdev->size) {
 661                         ofs -= subdev->size;
 662                         continue;
 663                 }
 664
 665                 err = mtd_block_markbad(subdev, ofs);
 666                 if (!err)
 667                         mtd->ecc_stats.badblocks++;
 668                 break;
 669         }
 670
 671         return err;
 672 }
 673
 674 /*
 675  * try to support NOMMU mmaps on concatenated devices
 676  * - we don't support subdev spanning as we can't guarantee it'll work
 677  */
 678 static unsigned long concat_get_unmapped_area(struct mtd_info *mtd,
 679                                               unsigned long len,
 680                                               unsigned long offset,
 681                                               unsigned long flags)
 682 {
 683         struct mtd_concat *concat = CONCAT(mtd);
 684         int i;
 685
 686         for (i = 0; i < concat->num_subdev; i++) {
 687                 struct mtd_info *subdev = concat->subdev[i];
 688
 689                 if (offset >= subdev->size) {
 690                         offset -= subdev->size;
 691                         continue;
 692                 }
 693
 694                 return mtd_get_unmapped_area(subdev, len, offset, flags);
 695         }
 696
 697         return (unsigned long) -ENOSYS;
 698 }
 699
 700 /*
 701  * This function constructs a virtual MTD device by concatenating
 702  * num_devs MTD devices. A pointer to the new device object is
 703  * stored to *new_dev upon success. This function does _not_
 704  * register any devices: this is the caller's responsibility.
 705  */
 706 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],   /* subdevices to concatenate */
 707                                    int num_devs,        /* number of subdevices      */
 708                                    const char *name)
 709 {                               /* name for the new device   */
 710         int i;
 711         size_t size;
 712         struct mtd_concat *concat;
 713         uint32_t max_erasesize, curr_erasesize;
 714         int num_erase_region;
 715         int max_writebufsize = 0;
 716
 717         printk(KERN_NOTICE "Concatenating MTD devices:\n");
 718         for (i = 0; i < num_devs; i++)
 719                 printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
 720         printk(KERN_NOTICE "into device \"%s\"\n", name);
 721
 722         /* allocate the device structure */
 723         size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
 724         concat = kzalloc(size, GFP_KERNEL);
 725         if (!concat) {
 726                 printk
 727                     ("memory allocation error while creating concatenated device \"%s\"\n",
 728                      name);
 729                 return NULL;
 730         }
 731         concat->subdev = (struct mtd_info **) (concat + 1);
 732
 733         /*
 734          * Set up the new "super" device's MTD object structure, check for
 735          * incompatibilities between the subdevices.
 736          */
 737         concat->mtd.type = subdev[0]->type;
 738         concat->mtd.flags = subdev[0]->flags;
 739         concat->mtd.size = subdev[0]->size;
 740         concat->mtd.erasesize = subdev[0]->erasesize;
 741         concat->mtd.writesize = subdev[0]->writesize;
 742
 743         for (i = 0; i < num_devs; i++)
 744                 if (max_writebufsize < subdev[i]->writebufsize)
 745                         max_writebufsize = subdev[i]->writebufsize;
 746         concat->mtd.writebufsize = max_writebufsize;
 747
 748         concat->mtd.subpage_sft = subdev[0]->subpage_sft;
 749         concat->mtd.oobsize = subdev[0]->oobsize;
 750         concat->mtd.oobavail = subdev[0]->oobavail;
 751         if (subdev[0]->_writev)
 752                 concat->mtd._writev = concat_writev;
 753         if (subdev[0]->_read_oob)
 754                 concat->mtd._read_oob = concat_read_oob;
 755         if (subdev[0]->_write_oob)
 756                 concat->mtd._write_oob = concat_write_oob;
 757         if (subdev[0]->_block_isbad)
 758                 concat->mtd._block_isbad = concat_block_isbad;
 759         if (subdev[0]->_block_markbad)
 760                 concat->mtd._block_markbad = concat_block_markbad;
 761
 762         concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
 763
 764         concat->mtd.backing_dev_info = subdev[0]->backing_dev_info;
 765
 766         concat->subdev[0] = subdev[0];
 767
 768         for (i = 1; i < num_devs; i++) {
 769                 if (concat->mtd.type != subdev[i]->type) {
 770                         kfree(concat);
 771                         printk("Incompatible device type on \"%s\"\n",
 772                                subdev[i]->name);
 773                         return NULL;
 774                 }
 775                 if (concat->mtd.flags != subdev[i]->flags) {
 776                         /*
 777                          * Expect all flags except MTD_WRITEABLE to be
 778                          * equal on all subdevices.
 779                          */
 780                         if ((concat->mtd.flags ^ subdev[i]->
 781                              flags) & ~MTD_WRITEABLE) {
 782                                 kfree(concat);
 783                                 printk("Incompatible device flags on \"%s\"\n",
 784                                        subdev[i]->name);
 785                                 return NULL;
 786                         } else
 787                                 /* if writeable attribute differs,
 788                                    make super device writeable */
 789                                 concat->mtd.flags |=
 790                                     subdev[i]->flags & MTD_WRITEABLE;
 791                 }
 792
 793                 /* only permit direct mapping if the BDIs are all the same
 794                  * - copy-mapping is still permitted
 795                  */
 796                 if (concat->mtd.backing_dev_info !=
 797                     subdev[i]->backing_dev_info)
 798                         concat->mtd.backing_dev_info =
 799                                 &default_backing_dev_info;
 800
 801                 concat->mtd.size += subdev[i]->size;
 802                 concat->mtd.ecc_stats.badblocks +=
 803                         subdev[i]->ecc_stats.badblocks;
 804                 if (concat->mtd.writesize   !=  subdev[i]->writesize ||
 805                     concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
 806                     concat->mtd.oobsize    !=  subdev[i]->oobsize ||
 807                     !concat->mtd._read_oob  != !subdev[i]->_read_oob ||
 808                     !concat->mtd._write_oob != !subdev[i]->_write_oob) {
 809                         kfree(concat);
 810                         printk("Incompatible OOB or ECC data on \"%s\"\n",
 811                                subdev[i]->name);
 812                         return NULL;
 813                 }
 814                 concat->subdev[i] = subdev[i];
 815
 816         }
 817
 818         concat->mtd.ecclayout = subdev[0]->ecclayout;
 819
 820         concat->num_subdev = num_devs;
 821         concat->mtd.name = name;
 822
 823         concat->mtd._erase = concat_erase;
 824         concat->mtd._read = concat_read;
 825         concat->mtd._write = concat_write;
 826         concat->mtd._sync = concat_sync;
 827         concat->mtd._lock = concat_lock;
 828         concat->mtd._unlock = concat_unlock;
 829         concat->mtd._suspend = concat_suspend;
 830         concat->mtd._resume = concat_resume;
 831         concat->mtd._get_unmapped_area = concat_get_unmapped_area;
 832
 833         /*
 834          * Combine the erase block size info of the subdevices:
 835          *
 836          * first, walk the map of the new device and see how
 837          * many changes in erase size we have
 838          */
 839         max_erasesize = curr_erasesize = subdev[0]->erasesize;
 840         num_erase_region = 1;
 841         for (i = 0; i < num_devs; i++) {
 842                 if (subdev[i]->numeraseregions == 0) {
 843                         /* current subdevice has uniform erase size */
 844                         if (subdev[i]->erasesize != curr_erasesize) {
 845                                 /* if it differs from the last subdevice's erase size, count it */
 846                                 ++num_erase_region;
 847                                 curr_erasesize = subdev[i]->erasesize;
 848                                 if (curr_erasesize > max_erasesize)
 849                                         max_erasesize = curr_erasesize;
 850                         }
 851                 } else {
 852                         /* current subdevice has variable erase size */
 853                         int j;
 854                         for (j = 0; j < subdev[i]->numeraseregions; j++) {
 855
 856                                 /* walk the list of erase regions, count any changes */
 857                                 if (subdev[i]->eraseregions[j].erasesize !=
 858                                     curr_erasesize) {
 859                                         ++num_erase_region;
 860                                         curr_erasesize =
 861                                             subdev[i]->eraseregions[j].
 862                                             erasesize;
 863                                         if (curr_erasesize > max_erasesize)
 864                                                 max_erasesize = curr_erasesize;
 865                                 }
 866                         }
 867                 }
 868         }
 869
 870         if (num_erase_region == 1) {
 871                 /*
 872                  * All subdevices have the same uniform erase size.
 873                  * This is easy:
 874                  */
 875                 concat->mtd.erasesize = curr_erasesize;
 876                 concat->mtd.numeraseregions = 0;
 877         } else {
 878                 uint64_t tmp64;
 879
 880                 /*
 881                  * erase block size varies across the subdevices: allocate
 882                  * space to store the data describing the variable erase regions
 883                  */
 884                 struct mtd_erase_region_info *erase_region_p;
 885                 uint64_t begin, position;
 886
 887                 concat->mtd.erasesize = max_erasesize;
 888                 concat->mtd.numeraseregions = num_erase_region;
 889                 concat->mtd.eraseregions = erase_region_p =
 890                     kmalloc(num_erase_region *
 891                             sizeof (struct mtd_erase_region_info), GFP_KERNEL);
 892                 if (!erase_region_p) {
 893                         kfree(concat);
 894                         printk
 895                             ("memory allocation error while creating erase region list"
 896                              " for device \"%s\"\n", name);
 897                         return NULL;
 898                 }
 899
 900                 /*
 901                  * walk the map of the new device once more and fill in
 902                  * in erase region info:
 903                  */
 904                 curr_erasesize = subdev[0]->erasesize;
 905                 begin = position = 0;
 906                 for (i = 0; i < num_devs; i++) {
 907                         if (subdev[i]->numeraseregions == 0) {
 908                                 /* current subdevice has uniform erase size */
 909                                 if (subdev[i]->erasesize != curr_erasesize) {
 910                                         /*
 911                                          *  fill in an mtd_erase_region_info structure for the area
 912                                          *  we have walked so far:
 913                                          */
 914                                         erase_region_p->offset = begin;
 915                                         erase_region_p->erasesize =
 916                                             curr_erasesize;
 917                                         tmp64 = position - begin;
 918                                         do_div(tmp64, curr_erasesize);
 919                                         erase_region_p->numblocks = tmp64;
 920                                         begin = position;
 921
 922                                         curr_erasesize = subdev[i]->erasesize;
 923                                         ++erase_region_p;
 924                                 }
 925                                 position += subdev[i]->size;
 926                         } else {
 927                                 /* current subdevice has variable erase size */
 928                                 int j;
 929                                 for (j = 0; j < subdev[i]->numeraseregions; j++) {
 930                                         /* walk the list of erase regions, count any changes */
 931                                         if (subdev[i]->eraseregions[j].
 932                                             erasesize != curr_erasesize) {
 933                                                 erase_region_p->offset = begin;
 934                                                 erase_region_p->erasesize =
 935                                                     curr_erasesize;
 936                                                 tmp64 = position - begin;
 937                                                 do_div(tmp64, curr_erasesize);
 938                                                 erase_region_p->numblocks = tmp64;
 939                                                 begin = position;
 940
 941                                                 curr_erasesize =
 942                                                     subdev[i]->eraseregions[j].
 943                                                     erasesize;
 944                                                 ++erase_region_p;
 945                                         }
 946                                         position +=
 947                                             subdev[i]->eraseregions[j].
 948                                             numblocks * (uint64_t)curr_erasesize;
 949                                 }
 950                         }
 951                 }
 952                 /* Now write the final entry */
 953                 erase_region_p->offset = begin;
 954                 erase_region_p->erasesize = curr_erasesize;
 955                 tmp64 = position - begin;
 956                 do_div(tmp64, curr_erasesize);
 957                 erase_region_p->numblocks = tmp64;
 958         }
 959
 960         return &concat->mtd;
 961 }
 962
 963 /*
 964  * This function destroys an MTD object obtained from concat_mtd_devs()
 965  */
 966
 967 void mtd_concat_destroy(struct mtd_info *mtd)
 968 {
 969         struct mtd_concat *concat = CONCAT(mtd);
 970         if (concat->mtd.numeraseregions)
 971                 kfree(concat->mtd.eraseregions);
 972         kfree(concat);
 973 }
 974
 975 EXPORT_SYMBOL(mtd_concat_create);
 976 EXPORT_SYMBOL(mtd_concat_destroy);
 977
 978 MODULE_LICENSE("GPL");
 979 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
 980 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");