drivers/mtd/mtdconcat.c

   1 /*
   2  * MTD device concatenation layer
   3  *
   4  * (C) 2002 Robert Kaiser <rkaiser@sysgo.de>
   5  *
   6  * NAND support by Christian Gan <cgan@iders.ca>
   7  *
   8  * This code is GPL
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/sched.h>
  15 #include <linux/types.h>
  16 #include <linux/backing-dev.h>
  17
  18 #include <linux/mtd/mtd.h>
  19 #include <linux/mtd/concat.h>
  20
  21 #include <asm/div64.h>
  22
  23 /*
  24  * Our storage structure:
  25  * Subdev points to an array of pointers to struct mtd_info objects
  26  * which is allocated along with this structure
  27  *
  28  */
  29 struct mtd_concat {
  30         struct mtd_info mtd;
  31         int num_subdev;
  32         struct mtd_info **subdev;
  33 };
  34
  35 /*
  36  * how to calculate the size required for the above structure,
  37  * including the pointer array subdev points to:
  38  */
  39 #define SIZEOF_STRUCT_MTD_CONCAT(num_subdev)    \
  40         ((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *)))
  41
  42 /*
  43  * Given a pointer to the MTD object in the mtd_concat structure,
  44  * we can retrieve the pointer to that structure with this macro.
  45  */
  46 #define CONCAT(x)  ((struct mtd_concat *)(x))
  47
  48 /*
  49  * MTD methods which look up the relevant subdevice, translate the
  50  * effective address and pass through to the subdevice.
  51  */
  52
  53 static int
  54 concat_read(struct mtd_info *mtd, loff_t from, size_t len,
  55             size_t * retlen, u_char * buf)
  56 {
  57         struct mtd_concat *concat = CONCAT(mtd);
  58         int ret = 0, err;
  59         int i;
  60
  61         *retlen = 0;
  62
  63         for (i = 0; i < concat->num_subdev; i++) {
  64                 struct mtd_info *subdev = concat->subdev[i];
  65                 size_t size, retsize;
  66
  67                 if (from >= subdev->size) {
  68                         /* Not destined for this subdev */
  69                         size = 0;
  70                         from -= subdev->size;
  71                         continue;
  72                 }
  73                 if (from + len > subdev->size)
  74                         /* First part goes into this subdev */
  75                         size = subdev->size - from;
  76                 else
  77                         /* Entire transaction goes into this subdev */
  78                         size = len;
  79
  80                 err = subdev->read(subdev, from, size, &retsize, buf);
  81
  82                 /* Save information about bitflips! */
  83                 if (unlikely(err)) {
  84                         if (err == -EBADMSG) {
  85                                 mtd->ecc_stats.failed++;
  86                                 ret = err;
  87                         } else if (err == -EUCLEAN) {
  88                                 mtd->ecc_stats.corrected++;
  89                                 /* Do not overwrite -EBADMSG !! */
  90                                 if (!ret)
  91                                         ret = err;
  92                         } else
  93                                 return err;
  94                 }
  95
  96                 *retlen += retsize;
  97                 len -= size;
  98                 if (len == 0)
  99                         return ret;
 100
 101                 buf += size;
 102                 from = 0;
 103         }
 104         return -EINVAL;
 105 }
 106
 107 static int
 108 concat_write(struct mtd_info *mtd, loff_t to, size_t len,
 109              size_t * retlen, const u_char * buf)
 110 {
 111         struct mtd_concat *concat = CONCAT(mtd);
 112         int err = -EINVAL;
 113         int i;
 114
 115         if (!(mtd->flags & MTD_WRITEABLE))
 116                 return -EROFS;
 117
 118         *retlen = 0;
 119
 120         for (i = 0; i < concat->num_subdev; i++) {
 121                 struct mtd_info *subdev = concat->subdev[i];
 122                 size_t size, retsize;
 123
 124                 if (to >= subdev->size) {
 125                         size = 0;
 126                         to -= subdev->size;
 127                         continue;
 128                 }
 129                 if (to + len > subdev->size)
 130                         size = subdev->size - to;
 131                 else
 132                         size = len;
 133
 134                 if (!(subdev->flags & MTD_WRITEABLE))
 135                         err = -EROFS;
 136                 else
 137                         err = subdev->write(subdev, to, size, &retsize, buf);
 138
 139                 if (err)
 140                         break;
 141
 142                 *retlen += retsize;
 143                 len -= size;
 144                 if (len == 0)
 145                         break;
 146
 147                 err = -EINVAL;
 148                 buf += size;
 149                 to = 0;
 150         }
 151         return err;
 152 }
 153
 154 static int
 155 concat_writev(struct mtd_info *mtd, const struct kvec *vecs,
 156                 unsigned long count, loff_t to, size_t * retlen)
 157 {
 158         struct mtd_concat *concat = CONCAT(mtd);
 159         struct kvec *vecs_copy;
 160         unsigned long entry_low, entry_high;
 161         size_t total_len = 0;
 162         int i;
 163         int err = -EINVAL;
 164
 165         if (!(mtd->flags & MTD_WRITEABLE))
 166                 return -EROFS;
 167
 168         *retlen = 0;
 169
 170         /* Calculate total length of data */
 171         for (i = 0; i < count; i++)
 172                 total_len += vecs[i].iov_len;
 173
 174         /* Do not allow write past end of device */
 175         if ((to + total_len) > mtd->size)
 176                 return -EINVAL;
 177
 178         /* Check alignment */
 179         if (mtd->writesize > 1) {
 180                 uint64_t __to = to;
 181                 if (do_div(__to, mtd->writesize) || (total_len % mtd->writesize))
 182                         return -EINVAL;
 183         }
 184
 185         /* make a copy of vecs */
 186         vecs_copy = kmemdup(vecs, sizeof(struct kvec) * count, GFP_KERNEL);
 187         if (!vecs_copy)
 188                 return -ENOMEM;
 189
 190         entry_low = 0;
 191         for (i = 0; i < concat->num_subdev; i++) {
 192                 struct mtd_info *subdev = concat->subdev[i];
 193                 size_t size, wsize, retsize, old_iov_len;
 194
 195                 if (to >= subdev->size) {
 196                         to -= subdev->size;
 197                         continue;
 198                 }
 199
 200                 size = min_t(uint64_t, total_len, subdev->size - to);
 201                 wsize = size; /* store for future use */
 202
 203                 entry_high = entry_low;
 204                 while (entry_high < count) {
 205                         if (size <= vecs_copy[entry_high].iov_len)
 206                                 break;
 207                         size -= vecs_copy[entry_high++].iov_len;
 208                 }
 209
 210                 old_iov_len = vecs_copy[entry_high].iov_len;
 211                 vecs_copy[entry_high].iov_len = size;
 212
 213                 if (!(subdev->flags & MTD_WRITEABLE))
 214                         err = -EROFS;
 215                 else
 216                         err = subdev->writev(subdev, &vecs_copy[entry_low],
 217                                 entry_high - entry_low + 1, to, &retsize);
 218
 219                 vecs_copy[entry_high].iov_len = old_iov_len - size;
 220                 vecs_copy[entry_high].iov_base += size;
 221
 222                 entry_low = entry_high;
 223
 224                 if (err)
 225                         break;
 226
 227                 *retlen += retsize;
 228                 total_len -= wsize;
 229
 230                 if (total_len == 0)
 231                         break;
 232
 233                 err = -EINVAL;
 234                 to = 0;
 235         }
 236
 237         kfree(vecs_copy);
 238         return err;
 239 }
 240
 241 static int
 242 concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
 243 {
 244         struct mtd_concat *concat = CONCAT(mtd);
 245         struct mtd_oob_ops devops = *ops;
 246         int i, err, ret = 0;
 247
 248         ops->retlen = ops->oobretlen = 0;
 249
 250         for (i = 0; i < concat->num_subdev; i++) {
 251                 struct mtd_info *subdev = concat->subdev[i];
 252
 253                 if (from >= subdev->size) {
 254                         from -= subdev->size;
 255                         continue;
 256                 }
 257
 258                 /* partial read ? */
 259                 if (from + devops.len > subdev->size)
 260                         devops.len = subdev->size - from;
 261
 262                 err = subdev->read_oob(subdev, from, &devops);
 263                 ops->retlen += devops.retlen;
 264                 ops->oobretlen += devops.oobretlen;
 265
 266                 /* Save information about bitflips! */
 267                 if (unlikely(err)) {
 268                         if (err == -EBADMSG) {
 269                                 mtd->ecc_stats.failed++;
 270                                 ret = err;
 271                         } else if (err == -EUCLEAN) {
 272                                 mtd->ecc_stats.corrected++;
 273                                 /* Do not overwrite -EBADMSG !! */
 274                                 if (!ret)
 275                                         ret = err;
 276                         } else
 277                                 return err;
 278                 }
 279
 280                 if (devops.datbuf) {
 281                         devops.len = ops->len - ops->retlen;
 282                         if (!devops.len)
 283                                 return ret;
 284                         devops.datbuf += devops.retlen;
 285                 }
 286                 if (devops.oobbuf) {
 287                         devops.ooblen = ops->ooblen - ops->oobretlen;
 288                         if (!devops.ooblen)
 289                                 return ret;
 290                         devops.oobbuf += ops->oobretlen;
 291                 }
 292
 293                 from = 0;
 294         }
 295         return -EINVAL;
 296 }
 297
 298 static int
 299 concat_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops)
 300 {
 301         struct mtd_concat *concat = CONCAT(mtd);
 302         struct mtd_oob_ops devops = *ops;
 303         int i, err;
 304
 305         if (!(mtd->flags & MTD_WRITEABLE))
 306                 return -EROFS;
 307
 308         ops->retlen = 0;
 309
 310         for (i = 0; i < concat->num_subdev; i++) {
 311                 struct mtd_info *subdev = concat->subdev[i];
 312
 313                 if (to >= subdev->size) {
 314                         to -= subdev->size;
 315                         continue;
 316                 }
 317
 318                 /* partial write ? */
 319                 if (to + devops.len > subdev->size)
 320                         devops.len = subdev->size - to;
 321
 322                 err = subdev->write_oob(subdev, to, &devops);
 323                 ops->retlen += devops.retlen;
 324                 if (err)
 325                         return err;
 326
 327                 if (devops.datbuf) {
 328                         devops.len = ops->len - ops->retlen;
 329                         if (!devops.len)
 330                                 return 0;
 331                         devops.datbuf += devops.retlen;
 332                 }
 333                 if (devops.oobbuf) {
 334                         devops.ooblen = ops->ooblen - ops->oobretlen;
 335                         if (!devops.ooblen)
 336                                 return 0;
 337                         devops.oobbuf += devops.oobretlen;
 338                 }
 339                 to = 0;
 340         }
 341         return -EINVAL;
 342 }
 343
 344 static void concat_erase_callback(struct erase_info *instr)
 345 {
 346         wake_up((wait_queue_head_t *) instr->priv);
 347 }
 348
 349 static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase)
 350 {
 351         int err;
 352         wait_queue_head_t waitq;
 353         DECLARE_WAITQUEUE(wait, current);
 354
 355         /*
 356          * This code was stol^H^H^H^Hinspired by mtdchar.c
 357          */
 358         init_waitqueue_head(&waitq);
 359
 360         erase->mtd = mtd;
 361         erase->callback = concat_erase_callback;
 362         erase->priv = (unsigned long) &waitq;
 363
 364         /*
 365          * FIXME: Allow INTERRUPTIBLE. Which means
 366          * not having the wait_queue head on the stack.
 367          */
 368         err = mtd->erase(mtd, erase);
 369         if (!err) {
 370                 set_current_state(TASK_UNINTERRUPTIBLE);
 371                 add_wait_queue(&waitq, &wait);
 372                 if (erase->state != MTD_ERASE_DONE
 373                     && erase->state != MTD_ERASE_FAILED)
 374                         schedule();
 375                 remove_wait_queue(&waitq, &wait);
 376                 set_current_state(TASK_RUNNING);
 377
 378                 err = (erase->state == MTD_ERASE_FAILED) ? -EIO : 0;
 379         }
 380         return err;
 381 }
 382
 383 static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
 384 {
 385         struct mtd_concat *concat = CONCAT(mtd);
 386         struct mtd_info *subdev;
 387         int i, err;
 388         uint64_t length, offset = 0;
 389         struct erase_info *erase;
 390
 391         if (!(mtd->flags & MTD_WRITEABLE))
 392                 return -EROFS;
 393
 394         if (instr->addr > concat->mtd.size)
 395                 return -EINVAL;
 396
 397         if (instr->len + instr->addr > concat->mtd.size)
 398                 return -EINVAL;
 399
 400         /*
 401          * Check for proper erase block alignment of the to-be-erased area.
 402          * It is easier to do this based on the super device's erase
 403          * region info rather than looking at each particular sub-device
 404          * in turn.
 405          */
 406         if (!concat->mtd.numeraseregions) {
 407                 /* the easy case: device has uniform erase block size */
 408                 if (instr->addr & (concat->mtd.erasesize - 1))
 409                         return -EINVAL;
 410                 if (instr->len & (concat->mtd.erasesize - 1))
 411                         return -EINVAL;
 412         } else {
 413                 /* device has variable erase size */
 414                 struct mtd_erase_region_info *erase_regions =
 415                     concat->mtd.eraseregions;
 416
 417                 /*
 418                  * Find the erase region where the to-be-erased area begins:
 419                  */
 420                 for (i = 0; i < concat->mtd.numeraseregions &&
 421                      instr->addr >= erase_regions[i].offset; i++) ;
 422                 --i;
 423
 424                 /*
 425                  * Now erase_regions[i] is the region in which the
 426                  * to-be-erased area begins. Verify that the starting
 427                  * offset is aligned to this region's erase size:
 428                  */
 429                 if (i < 0 || instr->addr & (erase_regions[i].erasesize - 1))
 430                         return -EINVAL;
 431
 432                 /*
 433                  * now find the erase region where the to-be-erased area ends:
 434                  */
 435                 for (; i < concat->mtd.numeraseregions &&
 436                      (instr->addr + instr->len) >= erase_regions[i].offset;
 437                      ++i) ;
 438                 --i;
 439                 /*
 440                  * check if the ending offset is aligned to this region's erase size
 441                  */
 442                 if (i < 0 || ((instr->addr + instr->len) &
 443                                         (erase_regions[i].erasesize - 1)))
 444                         return -EINVAL;
 445         }
 446
 447         instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
 448
 449         /* make a local copy of instr to avoid modifying the caller's struct */
 450         erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
 451
 452         if (!erase)
 453                 return -ENOMEM;
 454
 455         *erase = *instr;
 456         length = instr->len;
 457
 458         /*
 459          * find the subdevice where the to-be-erased area begins, adjust
 460          * starting offset to be relative to the subdevice start
 461          */
 462         for (i = 0; i < concat->num_subdev; i++) {
 463                 subdev = concat->subdev[i];
 464                 if (subdev->size <= erase->addr) {
 465                         erase->addr -= subdev->size;
 466                         offset += subdev->size;
 467                 } else {
 468                         break;
 469                 }
 470         }
 471
 472         /* must never happen since size limit has been verified above */
 473         BUG_ON(i >= concat->num_subdev);
 474
 475         /* now do the erase: */
 476         err = 0;
 477         for (; length > 0; i++) {
 478                 /* loop for all subdevices affected by this request */
 479                 subdev = concat->subdev[i];     /* get current subdevice */
 480
 481                 /* limit length to subdevice's size: */
 482                 if (erase->addr + length > subdev->size)
 483                         erase->len = subdev->size - erase->addr;
 484                 else
 485                         erase->len = length;
 486
 487                 if (!(subdev->flags & MTD_WRITEABLE)) {
 488                         err = -EROFS;
 489                         break;
 490                 }
 491                 length -= erase->len;
 492                 if ((err = concat_dev_erase(subdev, erase))) {
 493                         /* sanity check: should never happen since
 494                          * block alignment has been checked above */
 495                         BUG_ON(err == -EINVAL);
 496                         if (erase->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
 497                                 instr->fail_addr = erase->fail_addr + offset;
 498                         break;
 499                 }
 500                 /*
 501                  * erase->addr specifies the offset of the area to be
 502                  * erased *within the current subdevice*. It can be
 503                  * non-zero only the first time through this loop, i.e.
 504                  * for the first subdevice where blocks need to be erased.
 505                  * All the following erases must begin at the start of the
 506                  * current subdevice, i.e. at offset zero.
 507                  */
 508                 erase->addr = 0;
 509                 offset += subdev->size;
 510         }
 511         instr->state = erase->state;
 512         kfree(erase);
 513         if (err)
 514                 return err;
 515
 516         if (instr->callback)
 517                 instr->callback(instr);
 518         return 0;
 519 }
 520
 521 static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 522 {
 523         struct mtd_concat *concat = CONCAT(mtd);
 524         int i, err = -EINVAL;
 525
 526         if ((len + ofs) > mtd->size)
 527                 return -EINVAL;
 528
 529         for (i = 0; i < concat->num_subdev; i++) {
 530                 struct mtd_info *subdev = concat->subdev[i];
 531                 uint64_t size;
 532
 533                 if (ofs >= subdev->size) {
 534                         size = 0;
 535                         ofs -= subdev->size;
 536                         continue;
 537                 }
 538                 if (ofs + len > subdev->size)
 539                         size = subdev->size - ofs;
 540                 else
 541                         size = len;
 542
 543                 if (subdev->lock) {
 544                         err = subdev->lock(subdev, ofs, size);
 545                         if (err)
 546                                 break;
 547                 } else
 548                         err = -EOPNOTSUPP;
 549
 550                 len -= size;
 551                 if (len == 0)
 552                         break;
 553
 554                 err = -EINVAL;
 555                 ofs = 0;
 556         }
 557
 558         return err;
 559 }
 560
 561 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 562 {
 563         struct mtd_concat *concat = CONCAT(mtd);
 564         int i, err = 0;
 565
 566         if ((len + ofs) > mtd->size)
 567                 return -EINVAL;
 568
 569         for (i = 0; i < concat->num_subdev; i++) {
 570                 struct mtd_info *subdev = concat->subdev[i];
 571                 uint64_t size;
 572
 573                 if (ofs >= subdev->size) {
 574                         size = 0;
 575                         ofs -= subdev->size;
 576                         continue;
 577                 }
 578                 if (ofs + len > subdev->size)
 579                         size = subdev->size - ofs;
 580                 else
 581                         size = len;
 582
 583                 if (subdev->unlock) {
 584                         err = subdev->unlock(subdev, ofs, size);
 585                         if (err)
 586                                 break;
 587                 } else
 588                         err = -EOPNOTSUPP;
 589
 590                 len -= size;
 591                 if (len == 0)
 592                         break;
 593
 594                 err = -EINVAL;
 595                 ofs = 0;
 596         }
 597
 598         return err;
 599 }
 600
 601 static void concat_sync(struct mtd_info *mtd)
 602 {
 603         struct mtd_concat *concat = CONCAT(mtd);
 604         int i;
 605
 606         for (i = 0; i < concat->num_subdev; i++) {
 607                 struct mtd_info *subdev = concat->subdev[i];
 608                 subdev->sync(subdev);
 609         }
 610 }
 611
 612 static int concat_suspend(struct mtd_info *mtd)
 613 {
 614         struct mtd_concat *concat = CONCAT(mtd);
 615         int i, rc = 0;
 616
 617         for (i = 0; i < concat->num_subdev; i++) {
 618                 struct mtd_info *subdev = concat->subdev[i];
 619                 if ((rc = subdev->suspend(subdev)) < 0)
 620                         return rc;
 621         }
 622         return rc;
 623 }
 624
 625 static void concat_resume(struct mtd_info *mtd)
 626 {
 627         struct mtd_concat *concat = CONCAT(mtd);
 628         int i;
 629
 630         for (i = 0; i < concat->num_subdev; i++) {
 631                 struct mtd_info *subdev = concat->subdev[i];
 632                 subdev->resume(subdev);
 633         }
 634 }
 635
 636 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
 637 {
 638         struct mtd_concat *concat = CONCAT(mtd);
 639         int i, res = 0;
 640
 641         if (!concat->subdev[0]->block_isbad)
 642                 return res;
 643
 644         if (ofs > mtd->size)
 645                 return -EINVAL;
 646
 647         for (i = 0; i < concat->num_subdev; i++) {
 648                 struct mtd_info *subdev = concat->subdev[i];
 649
 650                 if (ofs >= subdev->size) {
 651                         ofs -= subdev->size;
 652                         continue;
 653                 }
 654
 655                 res = subdev->block_isbad(subdev, ofs);
 656                 break;
 657         }
 658
 659         return res;
 660 }
 661
 662 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
 663 {
 664         struct mtd_concat *concat = CONCAT(mtd);
 665         int i, err = -EINVAL;
 666
 667         if (!concat->subdev[0]->block_markbad)
 668                 return 0;
 669
 670         if (ofs > mtd->size)
 671                 return -EINVAL;
 672
 673         for (i = 0; i < concat->num_subdev; i++) {
 674                 struct mtd_info *subdev = concat->subdev[i];
 675
 676                 if (ofs >= subdev->size) {
 677                         ofs -= subdev->size;
 678                         continue;
 679                 }
 680
 681                 err = subdev->block_markbad(subdev, ofs);
 682                 if (!err)
 683                         mtd->ecc_stats.badblocks++;
 684                 break;
 685         }
 686
 687         return err;
 688 }
 689
 690 /*
 691  * try to support NOMMU mmaps on concatenated devices
 692  * - we don't support subdev spanning as we can't guarantee it'll work
 693  */
 694 static unsigned long concat_get_unmapped_area(struct mtd_info *mtd,
 695                                               unsigned long len,
 696                                               unsigned long offset,
 697                                               unsigned long flags)
 698 {
 699         struct mtd_concat *concat = CONCAT(mtd);
 700         int i;
 701
 702         for (i = 0; i < concat->num_subdev; i++) {
 703                 struct mtd_info *subdev = concat->subdev[i];
 704
 705                 if (offset >= subdev->size) {
 706                         offset -= subdev->size;
 707                         continue;
 708                 }
 709
 710                 /* we've found the subdev over which the mapping will reside */
 711                 if (offset + len > subdev->size)
 712                         return (unsigned long) -EINVAL;
 713
 714                 if (subdev->get_unmapped_area)
 715                         return subdev->get_unmapped_area(subdev, len, offset,
 716                                                          flags);
 717
 718                 break;
 719         }
 720
 721         return (unsigned long) -ENOSYS;
 722 }
 723
 724 /*
 725  * This function constructs a virtual MTD device by concatenating
 726  * num_devs MTD devices. A pointer to the new device object is
 727  * stored to *new_dev upon success. This function does _not_
 728  * register any devices: this is the caller's responsibility.
 729  */
 730 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],   /* subdevices to concatenate */
 731                                    int num_devs,        /* number of subdevices      */
 732                                    const char *name)
 733 {                               /* name for the new device   */
 734         int i;
 735         size_t size;
 736         struct mtd_concat *concat;
 737         uint32_t max_erasesize, curr_erasesize;
 738         int num_erase_region;
 739
 740         printk(KERN_NOTICE "Concatenating MTD devices:\n");
 741         for (i = 0; i < num_devs; i++)
 742                 printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
 743         printk(KERN_NOTICE "into device \"%s\"\n", name);
 744
 745         /* allocate the device structure */
 746         size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
 747         concat = kzalloc(size, GFP_KERNEL);
 748         if (!concat) {
 749                 printk
 750                     ("memory allocation error while creating concatenated device \"%s\"\n",
 751                      name);
 752                 return NULL;
 753         }
 754         concat->subdev = (struct mtd_info **) (concat + 1);
 755
 756         /*
 757          * Set up the new "super" device's MTD object structure, check for
 758          * incompatibilites between the subdevices.
 759          */
 760         concat->mtd.type = subdev[0]->type;
 761         concat->mtd.flags = subdev[0]->flags;
 762         concat->mtd.size = subdev[0]->size;
 763         concat->mtd.erasesize = subdev[0]->erasesize;
 764         concat->mtd.writesize = subdev[0]->writesize;
 765         concat->mtd.subpage_sft = subdev[0]->subpage_sft;
 766         concat->mtd.oobsize = subdev[0]->oobsize;
 767         concat->mtd.oobavail = subdev[0]->oobavail;
 768         if (subdev[0]->writev)
 769                 concat->mtd.writev = concat_writev;
 770         if (subdev[0]->read_oob)
 771                 concat->mtd.read_oob = concat_read_oob;
 772         if (subdev[0]->write_oob)
 773                 concat->mtd.write_oob = concat_write_oob;
 774         if (subdev[0]->block_isbad)
 775                 concat->mtd.block_isbad = concat_block_isbad;
 776         if (subdev[0]->block_markbad)
 777                 concat->mtd.block_markbad = concat_block_markbad;
 778
 779         concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
 780
 781         concat->mtd.backing_dev_info = subdev[0]->backing_dev_info;
 782
 783         concat->subdev[0] = subdev[0];
 784
 785         for (i = 1; i < num_devs; i++) {
 786                 if (concat->mtd.type != subdev[i]->type) {
 787                         kfree(concat);
 788                         printk("Incompatible device type on \"%s\"\n",
 789                                subdev[i]->name);
 790                         return NULL;
 791                 }
 792                 if (concat->mtd.flags != subdev[i]->flags) {
 793                         /*
 794                          * Expect all flags except MTD_WRITEABLE to be
 795                          * equal on all subdevices.
 796                          */
 797                         if ((concat->mtd.flags ^ subdev[i]->
 798                              flags) & ~MTD_WRITEABLE) {
 799                                 kfree(concat);
 800                                 printk("Incompatible device flags on \"%s\"\n",
 801                                        subdev[i]->name);
 802                                 return NULL;
 803                         } else
 804                                 /* if writeable attribute differs,
 805                                    make super device writeable */
 806                                 concat->mtd.flags |=
 807                                     subdev[i]->flags & MTD_WRITEABLE;
 808                 }
 809
 810                 /* only permit direct mapping if the BDIs are all the same
 811                  * - copy-mapping is still permitted
 812                  */
 813                 if (concat->mtd.backing_dev_info !=
 814                     subdev[i]->backing_dev_info)
 815                         concat->mtd.backing_dev_info =
 816                                 &default_backing_dev_info;
 817
 818                 concat->mtd.size += subdev[i]->size;
 819                 concat->mtd.ecc_stats.badblocks +=
 820                         subdev[i]->ecc_stats.badblocks;
 821                 if (concat->mtd.writesize   !=  subdev[i]->writesize ||
 822                     concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
 823                     concat->mtd.oobsize    !=  subdev[i]->oobsize ||
 824                     !concat->mtd.read_oob  != !subdev[i]->read_oob ||
 825                     !concat->mtd.write_oob != !subdev[i]->write_oob) {
 826                         kfree(concat);
 827                         printk("Incompatible OOB or ECC data on \"%s\"\n",
 828                                subdev[i]->name);
 829                         return NULL;
 830                 }
 831                 concat->subdev[i] = subdev[i];
 832
 833         }
 834
 835         concat->mtd.ecclayout = subdev[0]->ecclayout;
 836
 837         concat->num_subdev = num_devs;
 838         concat->mtd.name = name;
 839
 840         concat->mtd.erase = concat_erase;
 841         concat->mtd.read = concat_read;
 842         concat->mtd.write = concat_write;
 843         concat->mtd.sync = concat_sync;
 844         concat->mtd.lock = concat_lock;
 845         concat->mtd.unlock = concat_unlock;
 846         concat->mtd.suspend = concat_suspend;
 847         concat->mtd.resume = concat_resume;
 848         concat->mtd.get_unmapped_area = concat_get_unmapped_area;
 849
 850         /*
 851          * Combine the erase block size info of the subdevices:
 852          *
 853          * first, walk the map of the new device and see how
 854          * many changes in erase size we have
 855          */
 856         max_erasesize = curr_erasesize = subdev[0]->erasesize;
 857         num_erase_region = 1;
 858         for (i = 0; i < num_devs; i++) {
 859                 if (subdev[i]->numeraseregions == 0) {
 860                         /* current subdevice has uniform erase size */
 861                         if (subdev[i]->erasesize != curr_erasesize) {
 862                                 /* if it differs from the last subdevice's erase size, count it */
 863                                 ++num_erase_region;
 864                                 curr_erasesize = subdev[i]->erasesize;
 865                                 if (curr_erasesize > max_erasesize)
 866                                         max_erasesize = curr_erasesize;
 867                         }
 868                 } else {
 869                         /* current subdevice has variable erase size */
 870                         int j;
 871                         for (j = 0; j < subdev[i]->numeraseregions; j++) {
 872
 873                                 /* walk the list of erase regions, count any changes */
 874                                 if (subdev[i]->eraseregions[j].erasesize !=
 875                                     curr_erasesize) {
 876                                         ++num_erase_region;
 877                                         curr_erasesize =
 878                                             subdev[i]->eraseregions[j].
 879                                             erasesize;
 880                                         if (curr_erasesize > max_erasesize)
 881                                                 max_erasesize = curr_erasesize;
 882                                 }
 883                         }
 884                 }
 885         }
 886
 887         if (num_erase_region == 1) {
 888                 /*
 889                  * All subdevices have the same uniform erase size.
 890                  * This is easy:
 891                  */
 892                 concat->mtd.erasesize = curr_erasesize;
 893                 concat->mtd.numeraseregions = 0;
 894         } else {
 895                 uint64_t tmp64;
 896
 897                 /*
 898                  * erase block size varies across the subdevices: allocate
 899                  * space to store the data describing the variable erase regions
 900                  */
 901                 struct mtd_erase_region_info *erase_region_p;
 902                 uint64_t begin, position;
 903
 904                 concat->mtd.erasesize = max_erasesize;
 905                 concat->mtd.numeraseregions = num_erase_region;
 906                 concat->mtd.eraseregions = erase_region_p =
 907                     kmalloc(num_erase_region *
 908                             sizeof (struct mtd_erase_region_info), GFP_KERNEL);
 909                 if (!erase_region_p) {
 910                         kfree(concat);
 911                         printk
 912                             ("memory allocation error while creating erase region list"
 913                              " for device \"%s\"\n", name);
 914                         return NULL;
 915                 }
 916
 917                 /*
 918                  * walk the map of the new device once more and fill in
 919                  * in erase region info:
 920                  */
 921                 curr_erasesize = subdev[0]->erasesize;
 922                 begin = position = 0;
 923                 for (i = 0; i < num_devs; i++) {
 924                         if (subdev[i]->numeraseregions == 0) {
 925                                 /* current subdevice has uniform erase size */
 926                                 if (subdev[i]->erasesize != curr_erasesize) {
 927                                         /*
 928                                          *  fill in an mtd_erase_region_info structure for the area
 929                                          *  we have walked so far:
 930                                          */
 931                                         erase_region_p->offset = begin;
 932                                         erase_region_p->erasesize =
 933                                             curr_erasesize;
 934                                         tmp64 = position - begin;
 935                                         do_div(tmp64, curr_erasesize);
 936                                         erase_region_p->numblocks = tmp64;
 937                                         begin = position;
 938
 939                                         curr_erasesize = subdev[i]->erasesize;
 940                                         ++erase_region_p;
 941                                 }
 942                                 position += subdev[i]->size;
 943                         } else {
 944                                 /* current subdevice has variable erase size */
 945                                 int j;
 946                                 for (j = 0; j < subdev[i]->numeraseregions; j++) {
 947                                         /* walk the list of erase regions, count any changes */
 948                                         if (subdev[i]->eraseregions[j].
 949                                             erasesize != curr_erasesize) {
 950                                                 erase_region_p->offset = begin;
 951                                                 erase_region_p->erasesize =
 952                                                     curr_erasesize;
 953                                                 tmp64 = position - begin;
 954                                                 do_div(tmp64, curr_erasesize);
 955                                                 erase_region_p->numblocks = tmp64;
 956                                                 begin = position;
 957
 958                                                 curr_erasesize =
 959                                                     subdev[i]->eraseregions[j].
 960                                                     erasesize;
 961                                                 ++erase_region_p;
 962                                         }
 963                                         position +=
 964                                             subdev[i]->eraseregions[j].
 965                                             numblocks * (uint64_t)curr_erasesize;
 966                                 }
 967                         }
 968                 }
 969                 /* Now write the final entry */
 970                 erase_region_p->offset = begin;
 971                 erase_region_p->erasesize = curr_erasesize;
 972                 tmp64 = position - begin;
 973                 do_div(tmp64, curr_erasesize);
 974                 erase_region_p->numblocks = tmp64;
 975         }
 976
 977         return &concat->mtd;
 978 }
 979
 980 /*
 981  * This function destroys an MTD object obtained from concat_mtd_devs()
 982  */
 983
 984 void mtd_concat_destroy(struct mtd_info *mtd)
 985 {
 986         struct mtd_concat *concat = CONCAT(mtd);
 987         if (concat->mtd.numeraseregions)
 988                 kfree(concat->mtd.eraseregions);
 989         kfree(concat);
 990 }
 991
 992 EXPORT_SYMBOL(mtd_concat_create);
 993 EXPORT_SYMBOL(mtd_concat_destroy);
 994
 995 MODULE_LICENSE("GPL");
 996 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
 997 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");