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