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   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  * $Id: mtdconcat.c,v 1.11 2005/11/07 11:14:20 gleixner Exp $
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <linux/sched.h>
  17 #include <linux/types.h>
  18
  19 #include <linux/mtd/mtd.h>
  20 #include <linux/mtd/concat.h>
  21
  22 #include <asm/div64.h>
  23
  24 /*
  25  * Our storage structure:
  26  * Subdev points to an array of pointers to struct mtd_info objects
  27  * which is allocated along with this structure
  28  *
  29  */
  30 struct mtd_concat {
  31         struct mtd_info mtd;
  32         int num_subdev;
  33         struct mtd_info **subdev;
  34 };
  35
  36 /*
  37  * how to calculate the size required for the above structure,
  38  * including the pointer array subdev points to:
  39  */
  40 #define SIZEOF_STRUCT_MTD_CONCAT(num_subdev)    \
  41         ((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *)))
  42
  43 /*
  44  * Given a pointer to the MTD object in the mtd_concat structure,
  45  * we can retrieve the pointer to that structure with this macro.
  46  */
  47 #define CONCAT(x)  ((struct mtd_concat *)(x))
  48
  49 /*
  50  * MTD methods which look up the relevant subdevice, translate the
  51  * effective address and pass through to the subdevice.
  52  */
  53
  54 static int
  55 concat_read(struct mtd_info *mtd, loff_t from, size_t len,
  56             size_t * retlen, u_char * buf)
  57 {
  58         struct mtd_concat *concat = CONCAT(mtd);
  59         int err = -EINVAL;
  60         int i;
  61
  62         *retlen = 0;
  63
  64         for (i = 0; i < concat->num_subdev; i++) {
  65                 struct mtd_info *subdev = concat->subdev[i];
  66                 size_t size, retsize;
  67
  68                 if (from >= subdev->size) {
  69                         /* Not destined for this subdev */
  70                         size = 0;
  71                         from -= subdev->size;
  72                         continue;
  73                 }
  74                 if (from + len > subdev->size)
  75                         /* First part goes into this subdev */
  76                         size = subdev->size - from;
  77                 else
  78                         /* Entire transaction goes into this subdev */
  79                         size = len;
  80
  81                 err = subdev->read(subdev, from, size, &retsize, buf);
  82
  83                 if (err)
  84                         break;
  85
  86                 *retlen += retsize;
  87                 len -= size;
  88                 if (len == 0)
  89                         break;
  90
  91                 err = -EINVAL;
  92                 buf += size;
  93                 from = 0;
  94         }
  95         return err;
  96 }
  97
  98 static int
  99 concat_write(struct mtd_info *mtd, loff_t to, size_t len,
 100              size_t * retlen, const u_char * buf)
 101 {
 102         struct mtd_concat *concat = CONCAT(mtd);
 103         int err = -EINVAL;
 104         int i;
 105
 106         if (!(mtd->flags & MTD_WRITEABLE))
 107                 return -EROFS;
 108
 109         *retlen = 0;
 110
 111         for (i = 0; i < concat->num_subdev; i++) {
 112                 struct mtd_info *subdev = concat->subdev[i];
 113                 size_t size, retsize;
 114
 115                 if (to >= subdev->size) {
 116                         size = 0;
 117                         to -= subdev->size;
 118                         continue;
 119                 }
 120                 if (to + len > subdev->size)
 121                         size = subdev->size - to;
 122                 else
 123                         size = len;
 124
 125                 if (!(subdev->flags & MTD_WRITEABLE))
 126                         err = -EROFS;
 127                 else
 128                         err = subdev->write(subdev, to, size, &retsize, buf);
 129
 130                 if (err)
 131                         break;
 132
 133                 *retlen += retsize;
 134                 len -= size;
 135                 if (len == 0)
 136                         break;
 137
 138                 err = -EINVAL;
 139                 buf += size;
 140                 to = 0;
 141         }
 142         return err;
 143 }
 144
 145 static int
 146 concat_writev(struct mtd_info *mtd, const struct kvec *vecs,
 147                 unsigned long count, loff_t to, size_t * retlen)
 148 {
 149         struct mtd_concat *concat = CONCAT(mtd);
 150         struct kvec *vecs_copy;
 151         unsigned long entry_low, entry_high;
 152         size_t total_len = 0;
 153         int i;
 154         int err = -EINVAL;
 155
 156         if (!(mtd->flags & MTD_WRITEABLE))
 157                 return -EROFS;
 158
 159         *retlen = 0;
 160
 161         /* Calculate total length of data */
 162         for (i = 0; i < count; i++)
 163                 total_len += vecs[i].iov_len;
 164
 165         /* Do not allow write past end of device */
 166         if ((to + total_len) > mtd->size)
 167                 return -EINVAL;
 168
 169         /* Check alignment */
 170         if (mtd->writesize > 1) {
 171                 loff_t __to = to;
 172                 if (do_div(__to, mtd->writesize) || (total_len % mtd->writesize))
 173                         return -EINVAL;
 174         }
 175
 176         /* make a copy of vecs */
 177         vecs_copy = kmalloc(sizeof(struct kvec) * count, GFP_KERNEL);
 178         if (!vecs_copy)
 179                 return -ENOMEM;
 180         memcpy(vecs_copy, vecs, sizeof(struct kvec) * count);
 181
 182         entry_low = 0;
 183         for (i = 0; i < concat->num_subdev; i++) {
 184                 struct mtd_info *subdev = concat->subdev[i];
 185                 size_t size, wsize, retsize, old_iov_len;
 186
 187                 if (to >= subdev->size) {
 188                         to -= subdev->size;
 189                         continue;
 190                 }
 191
 192                 size = min(total_len, (size_t)(subdev->size - to));
 193                 wsize = size; /* store for future use */
 194
 195                 entry_high = entry_low;
 196                 while (entry_high < count) {
 197                         if (size <= vecs_copy[entry_high].iov_len)
 198                                 break;
 199                         size -= vecs_copy[entry_high++].iov_len;
 200                 }
 201
 202                 old_iov_len = vecs_copy[entry_high].iov_len;
 203                 vecs_copy[entry_high].iov_len = size;
 204
 205                 if (!(subdev->flags & MTD_WRITEABLE))
 206                         err = -EROFS;
 207                 else
 208                         err = subdev->writev(subdev, &vecs_copy[entry_low],
 209                                 entry_high - entry_low + 1, to, &retsize);
 210
 211                 vecs_copy[entry_high].iov_len = old_iov_len - size;
 212                 vecs_copy[entry_high].iov_base += size;
 213
 214                 entry_low = entry_high;
 215
 216                 if (err)
 217                         break;
 218
 219                 *retlen += retsize;
 220                 total_len -= wsize;
 221
 222                 if (total_len == 0)
 223                         break;
 224
 225                 err = -EINVAL;
 226                 to = 0;
 227         }
 228
 229         kfree(vecs_copy);
 230         return err;
 231 }
 232
 233 static int
 234 concat_read_oob(struct mtd_info *mtd, loff_t from, size_t len,
 235                 size_t * retlen, u_char * buf)
 236 {
 237         struct mtd_concat *concat = CONCAT(mtd);
 238         int err = -EINVAL;
 239         int i;
 240
 241         *retlen = 0;
 242
 243         for (i = 0; i < concat->num_subdev; i++) {
 244                 struct mtd_info *subdev = concat->subdev[i];
 245                 size_t size, retsize;
 246
 247                 if (from >= subdev->size) {
 248                         /* Not destined for this subdev */
 249                         size = 0;
 250                         from -= subdev->size;
 251                         continue;
 252                 }
 253                 if (from + len > subdev->size)
 254                         /* First part goes into this subdev */
 255                         size = subdev->size - from;
 256                 else
 257                         /* Entire transaction goes into this subdev */
 258                         size = len;
 259
 260                 if (subdev->read_oob)
 261                         err = subdev->read_oob(subdev, from, size,
 262                                                &retsize, buf);
 263                 else
 264                         err = -EINVAL;
 265
 266                 if (err)
 267                         break;
 268
 269                 *retlen += retsize;
 270                 len -= size;
 271                 if (len == 0)
 272                         break;
 273
 274                 err = -EINVAL;
 275                 buf += size;
 276                 from = 0;
 277         }
 278         return err;
 279 }
 280
 281 static int
 282 concat_write_oob(struct mtd_info *mtd, loff_t to, size_t len,
 283                  size_t * retlen, const u_char * buf)
 284 {
 285         struct mtd_concat *concat = CONCAT(mtd);
 286         int err = -EINVAL;
 287         int i;
 288
 289         if (!(mtd->flags & MTD_WRITEABLE))
 290                 return -EROFS;
 291
 292         *retlen = 0;
 293
 294         for (i = 0; i < concat->num_subdev; i++) {
 295                 struct mtd_info *subdev = concat->subdev[i];
 296                 size_t size, retsize;
 297
 298                 if (to >= subdev->size) {
 299                         size = 0;
 300                         to -= subdev->size;
 301                         continue;
 302                 }
 303                 if (to + len > subdev->size)
 304                         size = subdev->size - to;
 305                 else
 306                         size = len;
 307
 308                 if (!(subdev->flags & MTD_WRITEABLE))
 309                         err = -EROFS;
 310                 else if (subdev->write_oob)
 311                         err = subdev->write_oob(subdev, to, size, &retsize,
 312                                                 buf);
 313                 else
 314                         err = -EINVAL;
 315
 316                 if (err)
 317                         break;
 318
 319                 *retlen += retsize;
 320                 len -= size;
 321                 if (len == 0)
 322                         break;
 323
 324                 err = -EINVAL;
 325                 buf += size;
 326                 to = 0;
 327         }
 328         return err;
 329 }
 330
 331 static void concat_erase_callback(struct erase_info *instr)
 332 {
 333         wake_up((wait_queue_head_t *) instr->priv);
 334 }
 335
 336 static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase)
 337 {
 338         int err;
 339         wait_queue_head_t waitq;
 340         DECLARE_WAITQUEUE(wait, current);
 341
 342         /*
 343          * This code was stol^H^H^H^Hinspired by mtdchar.c
 344          */
 345         init_waitqueue_head(&waitq);
 346
 347         erase->mtd = mtd;
 348         erase->callback = concat_erase_callback;
 349         erase->priv = (unsigned long) &waitq;
 350
 351         /*
 352          * FIXME: Allow INTERRUPTIBLE. Which means
 353          * not having the wait_queue head on the stack.
 354          */
 355         err = mtd->erase(mtd, erase);
 356         if (!err) {
 357                 set_current_state(TASK_UNINTERRUPTIBLE);
 358                 add_wait_queue(&waitq, &wait);
 359                 if (erase->state != MTD_ERASE_DONE
 360                     && erase->state != MTD_ERASE_FAILED)
 361                         schedule();
 362                 remove_wait_queue(&waitq, &wait);
 363                 set_current_state(TASK_RUNNING);
 364
 365                 err = (erase->state == MTD_ERASE_FAILED) ? -EIO : 0;
 366         }
 367         return err;
 368 }
 369
 370 static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
 371 {
 372         struct mtd_concat *concat = CONCAT(mtd);
 373         struct mtd_info *subdev;
 374         int i, err;
 375         u_int32_t length, offset = 0;
 376         struct erase_info *erase;
 377
 378         if (!(mtd->flags & MTD_WRITEABLE))
 379                 return -EROFS;
 380
 381         if (instr->addr > concat->mtd.size)
 382                 return -EINVAL;
 383
 384         if (instr->len + instr->addr > concat->mtd.size)
 385                 return -EINVAL;
 386
 387         /*
 388          * Check for proper erase block alignment of the to-be-erased area.
 389          * It is easier to do this based on the super device's erase
 390          * region info rather than looking at each particular sub-device
 391          * in turn.
 392          */
 393         if (!concat->mtd.numeraseregions) {
 394                 /* the easy case: device has uniform erase block size */
 395                 if (instr->addr & (concat->mtd.erasesize - 1))
 396                         return -EINVAL;
 397                 if (instr->len & (concat->mtd.erasesize - 1))
 398                         return -EINVAL;
 399         } else {
 400                 /* device has variable erase size */
 401                 struct mtd_erase_region_info *erase_regions =
 402                     concat->mtd.eraseregions;
 403
 404                 /*
 405                  * Find the erase region where the to-be-erased area begins:
 406                  */
 407                 for (i = 0; i < concat->mtd.numeraseregions &&
 408                      instr->addr >= erase_regions[i].offset; i++) ;
 409                 --i;
 410
 411                 /*
 412                  * Now erase_regions[i] is the region in which the
 413                  * to-be-erased area begins. Verify that the starting
 414                  * offset is aligned to this region's erase size:
 415                  */
 416                 if (instr->addr & (erase_regions[i].erasesize - 1))
 417                         return -EINVAL;
 418
 419                 /*
 420                  * now find the erase region where the to-be-erased area ends:
 421                  */
 422                 for (; i < concat->mtd.numeraseregions &&
 423                      (instr->addr + instr->len) >= erase_regions[i].offset;
 424                      ++i) ;
 425                 --i;
 426                 /*
 427                  * check if the ending offset is aligned to this region's erase size
 428                  */
 429                 if ((instr->addr + instr->len) & (erase_regions[i].erasesize -
 430                                                   1))
 431                         return -EINVAL;
 432         }
 433
 434         instr->fail_addr = 0xffffffff;
 435
 436         /* make a local copy of instr to avoid modifying the caller's struct */
 437         erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
 438
 439         if (!erase)
 440                 return -ENOMEM;
 441
 442         *erase = *instr;
 443         length = instr->len;
 444
 445         /*
 446          * find the subdevice where the to-be-erased area begins, adjust
 447          * starting offset to be relative to the subdevice start
 448          */
 449         for (i = 0; i < concat->num_subdev; i++) {
 450                 subdev = concat->subdev[i];
 451                 if (subdev->size <= erase->addr) {
 452                         erase->addr -= subdev->size;
 453                         offset += subdev->size;
 454                 } else {
 455                         break;
 456                 }
 457         }
 458
 459         /* must never happen since size limit has been verified above */
 460         BUG_ON(i >= concat->num_subdev);
 461
 462         /* now do the erase: */
 463         err = 0;
 464         for (; length > 0; i++) {
 465                 /* loop for all subdevices affected by this request */
 466                 subdev = concat->subdev[i];     /* get current subdevice */
 467
 468                 /* limit length to subdevice's size: */
 469                 if (erase->addr + length > subdev->size)
 470                         erase->len = subdev->size - erase->addr;
 471                 else
 472                         erase->len = length;
 473
 474                 if (!(subdev->flags & MTD_WRITEABLE)) {
 475                         err = -EROFS;
 476                         break;
 477                 }
 478                 length -= erase->len;
 479                 if ((err = concat_dev_erase(subdev, erase))) {
 480                         /* sanity check: should never happen since
 481                          * block alignment has been checked above */
 482                         BUG_ON(err == -EINVAL);
 483                         if (erase->fail_addr != 0xffffffff)
 484                                 instr->fail_addr = erase->fail_addr + offset;
 485                         break;
 486                 }
 487                 /*
 488                  * erase->addr specifies the offset of the area to be
 489                  * erased *within the current subdevice*. It can be
 490                  * non-zero only the first time through this loop, i.e.
 491                  * for the first subdevice where blocks need to be erased.
 492                  * All the following erases must begin at the start of the
 493                  * current subdevice, i.e. at offset zero.
 494                  */
 495                 erase->addr = 0;
 496                 offset += subdev->size;
 497         }
 498         instr->state = erase->state;
 499         kfree(erase);
 500         if (err)
 501                 return err;
 502
 503         if (instr->callback)
 504                 instr->callback(instr);
 505         return 0;
 506 }
 507
 508 static int concat_lock(struct mtd_info *mtd, loff_t ofs, size_t len)
 509 {
 510         struct mtd_concat *concat = CONCAT(mtd);
 511         int i, err = -EINVAL;
 512
 513         if ((len + ofs) > mtd->size)
 514                 return -EINVAL;
 515
 516         for (i = 0; i < concat->num_subdev; i++) {
 517                 struct mtd_info *subdev = concat->subdev[i];
 518                 size_t size;
 519
 520                 if (ofs >= subdev->size) {
 521                         size = 0;
 522                         ofs -= subdev->size;
 523                         continue;
 524                 }
 525                 if (ofs + len > subdev->size)
 526                         size = subdev->size - ofs;
 527                 else
 528                         size = len;
 529
 530                 err = subdev->lock(subdev, ofs, size);
 531
 532                 if (err)
 533                         break;
 534
 535                 len -= size;
 536                 if (len == 0)
 537                         break;
 538
 539                 err = -EINVAL;
 540                 ofs = 0;
 541         }
 542
 543         return err;
 544 }
 545
 546 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, size_t len)
 547 {
 548         struct mtd_concat *concat = CONCAT(mtd);
 549         int i, err = 0;
 550
 551         if ((len + ofs) > mtd->size)
 552                 return -EINVAL;
 553
 554         for (i = 0; i < concat->num_subdev; i++) {
 555                 struct mtd_info *subdev = concat->subdev[i];
 556                 size_t size;
 557
 558                 if (ofs >= subdev->size) {
 559                         size = 0;
 560                         ofs -= subdev->size;
 561                         continue;
 562                 }
 563                 if (ofs + len > subdev->size)
 564                         size = subdev->size - ofs;
 565                 else
 566                         size = len;
 567
 568                 err = subdev->unlock(subdev, ofs, size);
 569
 570                 if (err)
 571                         break;
 572
 573                 len -= size;
 574                 if (len == 0)
 575                         break;
 576
 577                 err = -EINVAL;
 578                 ofs = 0;
 579         }
 580
 581         return err;
 582 }
 583
 584 static void concat_sync(struct mtd_info *mtd)
 585 {
 586         struct mtd_concat *concat = CONCAT(mtd);
 587         int i;
 588
 589         for (i = 0; i < concat->num_subdev; i++) {
 590                 struct mtd_info *subdev = concat->subdev[i];
 591                 subdev->sync(subdev);
 592         }
 593 }
 594
 595 static int concat_suspend(struct mtd_info *mtd)
 596 {
 597         struct mtd_concat *concat = CONCAT(mtd);
 598         int i, rc = 0;
 599
 600         for (i = 0; i < concat->num_subdev; i++) {
 601                 struct mtd_info *subdev = concat->subdev[i];
 602                 if ((rc = subdev->suspend(subdev)) < 0)
 603                         return rc;
 604         }
 605         return rc;
 606 }
 607
 608 static void concat_resume(struct mtd_info *mtd)
 609 {
 610         struct mtd_concat *concat = CONCAT(mtd);
 611         int i;
 612
 613         for (i = 0; i < concat->num_subdev; i++) {
 614                 struct mtd_info *subdev = concat->subdev[i];
 615                 subdev->resume(subdev);
 616         }
 617 }
 618
 619 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
 620 {
 621         struct mtd_concat *concat = CONCAT(mtd);
 622         int i, res = 0;
 623
 624         if (!concat->subdev[0]->block_isbad)
 625                 return res;
 626
 627         if (ofs > mtd->size)
 628                 return -EINVAL;
 629
 630         for (i = 0; i < concat->num_subdev; i++) {
 631                 struct mtd_info *subdev = concat->subdev[i];
 632
 633                 if (ofs >= subdev->size) {
 634                         ofs -= subdev->size;
 635                         continue;
 636                 }
 637
 638                 res = subdev->block_isbad(subdev, ofs);
 639                 break;
 640         }
 641
 642         return res;
 643 }
 644
 645 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
 646 {
 647         struct mtd_concat *concat = CONCAT(mtd);
 648         int i, err = -EINVAL;
 649
 650         if (!concat->subdev[0]->block_markbad)
 651                 return 0;
 652
 653         if (ofs > mtd->size)
 654                 return -EINVAL;
 655
 656         for (i = 0; i < concat->num_subdev; i++) {
 657                 struct mtd_info *subdev = concat->subdev[i];
 658
 659                 if (ofs >= subdev->size) {
 660                         ofs -= subdev->size;
 661                         continue;
 662                 }
 663
 664                 err = subdev->block_markbad(subdev, ofs);
 665                 break;
 666         }
 667
 668         return err;
 669 }
 670
 671 /*
 672  * This function constructs a virtual MTD device by concatenating
 673  * num_devs MTD devices. A pointer to the new device object is
 674  * stored to *new_dev upon success. This function does _not_
 675  * register any devices: this is the caller's responsibility.
 676  */
 677 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],   /* subdevices to concatenate */
 678                                    int num_devs,        /* number of subdevices      */
 679                                    char *name)
 680 {                               /* name for the new device   */
 681         int i;
 682         size_t size;
 683         struct mtd_concat *concat;
 684         u_int32_t max_erasesize, curr_erasesize;
 685         int num_erase_region;
 686
 687         printk(KERN_NOTICE "Concatenating MTD devices:\n");
 688         for (i = 0; i < num_devs; i++)
 689                 printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
 690         printk(KERN_NOTICE "into device \"%s\"\n", name);
 691
 692         /* allocate the device structure */
 693         size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
 694         concat = kmalloc(size, GFP_KERNEL);
 695         if (!concat) {
 696                 printk
 697                     ("memory allocation error while creating concatenated device \"%s\"\n",
 698                      name);
 699                 return NULL;
 700         }
 701         memset(concat, 0, size);
 702         concat->subdev = (struct mtd_info **) (concat + 1);
 703
 704         /*
 705          * Set up the new "super" device's MTD object structure, check for
 706          * incompatibilites between the subdevices.
 707          */
 708         concat->mtd.type = subdev[0]->type;
 709         concat->mtd.flags = subdev[0]->flags;
 710         concat->mtd.size = subdev[0]->size;
 711         concat->mtd.erasesize = subdev[0]->erasesize;
 712         concat->mtd.writesize = subdev[0]->writesize;
 713         concat->mtd.oobsize = subdev[0]->oobsize;
 714         concat->mtd.ecctype = subdev[0]->ecctype;
 715         concat->mtd.eccsize = subdev[0]->eccsize;
 716         if (subdev[0]->writev)
 717                 concat->mtd.writev = concat_writev;
 718         if (subdev[0]->read_oob)
 719                 concat->mtd.read_oob = concat_read_oob;
 720         if (subdev[0]->write_oob)
 721                 concat->mtd.write_oob = concat_write_oob;
 722         if (subdev[0]->block_isbad)
 723                 concat->mtd.block_isbad = concat_block_isbad;
 724         if (subdev[0]->block_markbad)
 725                 concat->mtd.block_markbad = concat_block_markbad;
 726
 727         concat->subdev[0] = subdev[0];
 728
 729         for (i = 1; i < num_devs; i++) {
 730                 if (concat->mtd.type != subdev[i]->type) {
 731                         kfree(concat);
 732                         printk("Incompatible device type on \"%s\"\n",
 733                                subdev[i]->name);
 734                         return NULL;
 735                 }
 736                 if (concat->mtd.flags != subdev[i]->flags) {
 737                         /*
 738                          * Expect all flags except MTD_WRITEABLE to be
 739                          * equal on all subdevices.
 740                          */
 741                         if ((concat->mtd.flags ^ subdev[i]->
 742                              flags) & ~MTD_WRITEABLE) {
 743                                 kfree(concat);
 744                                 printk("Incompatible device flags on \"%s\"\n",
 745                                        subdev[i]->name);
 746                                 return NULL;
 747                         } else
 748                                 /* if writeable attribute differs,
 749                                    make super device writeable */
 750                                 concat->mtd.flags |=
 751                                     subdev[i]->flags & MTD_WRITEABLE;
 752                 }
 753                 concat->mtd.size += subdev[i]->size;
 754                 if (concat->mtd.writesize   !=  subdev[i]->writesize ||
 755                     concat->mtd.oobsize    !=  subdev[i]->oobsize ||
 756                     concat->mtd.ecctype    !=  subdev[i]->ecctype ||
 757                     concat->mtd.eccsize    !=  subdev[i]->eccsize ||
 758                     !concat->mtd.read_oob  != !subdev[i]->read_oob ||
 759                     !concat->mtd.write_oob != !subdev[i]->write_oob) {
 760                         kfree(concat);
 761                         printk("Incompatible OOB or ECC data on \"%s\"\n",
 762                                subdev[i]->name);
 763                         return NULL;
 764                 }
 765                 concat->subdev[i] = subdev[i];
 766
 767         }
 768
 769         if(concat->mtd.type == MTD_NANDFLASH)
 770                 memcpy(&concat->mtd.oobinfo, &subdev[0]->oobinfo,
 771                         sizeof(struct nand_oobinfo));
 772
 773         concat->num_subdev = num_devs;
 774         concat->mtd.name = name;
 775
 776         concat->mtd.erase = concat_erase;
 777         concat->mtd.read = concat_read;
 778         concat->mtd.write = concat_write;
 779         concat->mtd.sync = concat_sync;
 780         concat->mtd.lock = concat_lock;
 781         concat->mtd.unlock = concat_unlock;
 782         concat->mtd.suspend = concat_suspend;
 783         concat->mtd.resume = concat_resume;
 784
 785         /*
 786          * Combine the erase block size info of the subdevices:
 787          *
 788          * first, walk the map of the new device and see how
 789          * many changes in erase size we have
 790          */
 791         max_erasesize = curr_erasesize = subdev[0]->erasesize;
 792         num_erase_region = 1;
 793         for (i = 0; i < num_devs; i++) {
 794                 if (subdev[i]->numeraseregions == 0) {
 795                         /* current subdevice has uniform erase size */
 796                         if (subdev[i]->erasesize != curr_erasesize) {
 797                                 /* if it differs from the last subdevice's erase size, count it */
 798                                 ++num_erase_region;
 799                                 curr_erasesize = subdev[i]->erasesize;
 800                                 if (curr_erasesize > max_erasesize)
 801                                         max_erasesize = curr_erasesize;
 802                         }
 803                 } else {
 804                         /* current subdevice has variable erase size */
 805                         int j;
 806                         for (j = 0; j < subdev[i]->numeraseregions; j++) {
 807
 808                                 /* walk the list of erase regions, count any changes */
 809                                 if (subdev[i]->eraseregions[j].erasesize !=
 810                                     curr_erasesize) {
 811                                         ++num_erase_region;
 812                                         curr_erasesize =
 813                                             subdev[i]->eraseregions[j].
 814                                             erasesize;
 815                                         if (curr_erasesize > max_erasesize)
 816                                                 max_erasesize = curr_erasesize;
 817                                 }
 818                         }
 819                 }
 820         }
 821
 822         if (num_erase_region == 1) {
 823                 /*
 824                  * All subdevices have the same uniform erase size.
 825                  * This is easy:
 826                  */
 827                 concat->mtd.erasesize = curr_erasesize;
 828                 concat->mtd.numeraseregions = 0;
 829         } else {
 830                 /*
 831                  * erase block size varies across the subdevices: allocate
 832                  * space to store the data describing the variable erase regions
 833                  */
 834                 struct mtd_erase_region_info *erase_region_p;
 835                 u_int32_t begin, position;
 836
 837                 concat->mtd.erasesize = max_erasesize;
 838                 concat->mtd.numeraseregions = num_erase_region;
 839                 concat->mtd.eraseregions = erase_region_p =
 840                     kmalloc(num_erase_region *
 841                             sizeof (struct mtd_erase_region_info), GFP_KERNEL);
 842                 if (!erase_region_p) {
 843                         kfree(concat);
 844                         printk
 845                             ("memory allocation error while creating erase region list"
 846                              " for device \"%s\"\n", name);
 847                         return NULL;
 848                 }
 849
 850                 /*
 851                  * walk the map of the new device once more and fill in
 852                  * in erase region info:
 853                  */
 854                 curr_erasesize = subdev[0]->erasesize;
 855                 begin = position = 0;
 856                 for (i = 0; i < num_devs; i++) {
 857                         if (subdev[i]->numeraseregions == 0) {
 858                                 /* current subdevice has uniform erase size */
 859                                 if (subdev[i]->erasesize != curr_erasesize) {
 860                                         /*
 861                                          *  fill in an mtd_erase_region_info structure for the area
 862                                          *  we have walked so far:
 863                                          */
 864                                         erase_region_p->offset = begin;
 865                                         erase_region_p->erasesize =
 866                                             curr_erasesize;
 867                                         erase_region_p->numblocks =
 868                                             (position - begin) / curr_erasesize;
 869                                         begin = position;
 870
 871                                         curr_erasesize = subdev[i]->erasesize;
 872                                         ++erase_region_p;
 873                                 }
 874                                 position += subdev[i]->size;
 875                         } else {
 876                                 /* current subdevice has variable erase size */
 877                                 int j;
 878                                 for (j = 0; j < subdev[i]->numeraseregions; j++) {
 879                                         /* walk the list of erase regions, count any changes */
 880                                         if (subdev[i]->eraseregions[j].
 881                                             erasesize != curr_erasesize) {
 882                                                 erase_region_p->offset = begin;
 883                                                 erase_region_p->erasesize =
 884                                                     curr_erasesize;
 885                                                 erase_region_p->numblocks =
 886                                                     (position -
 887                                                      begin) / curr_erasesize;
 888                                                 begin = position;
 889
 890                                                 curr_erasesize =
 891                                                     subdev[i]->eraseregions[j].
 892                                                     erasesize;
 893                                                 ++erase_region_p;
 894                                         }
 895                                         position +=
 896                                             subdev[i]->eraseregions[j].
 897                                             numblocks * curr_erasesize;
 898                                 }
 899                         }
 900                 }
 901                 /* Now write the final entry */
 902                 erase_region_p->offset = begin;
 903                 erase_region_p->erasesize = curr_erasesize;
 904                 erase_region_p->numblocks = (position - begin) / curr_erasesize;
 905         }
 906
 907         return &concat->mtd;
 908 }
 909
 910 /*
 911  * This function destroys an MTD object obtained from concat_mtd_devs()
 912  */
 913
 914 void mtd_concat_destroy(struct mtd_info *mtd)
 915 {
 916         struct mtd_concat *concat = CONCAT(mtd);
 917         if (concat->mtd.numeraseregions)
 918                 kfree(concat->mtd.eraseregions);
 919         kfree(concat);
 920 }
 921
 922 EXPORT_SYMBOL(mtd_concat_create);
 923 EXPORT_SYMBOL(mtd_concat_destroy);
 924
 925 MODULE_LICENSE("GPL");
 926 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
 927 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");