drivers/mtd/mtdconcat.c

   1 /*
   2  * MTD device concatenation layer
   3  *
   4  * Copyright © 2002 Robert Kaiser <rkaiser@sysgo.de>
   5  * Copyright © 2002-2010 David Woodhouse <dwmw2@infradead.org>
   6  *
   7  * NAND support by Christian Gan <cgan@iders.ca>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  22  *
  23  */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/module.h>
  27 #include <linux/slab.h>
  28 #include <linux/sched.h>
  29 #include <linux/types.h>
  30 #include <linux/backing-dev.h>
  31
  32 #include <linux/mtd/mtd.h>
  33 #include <linux/mtd/concat.h>
  34
  35 #include <asm/div64.h>
  36
  37 /*
  38  * Our storage structure:
  39  * Subdev points to an array of pointers to struct mtd_info objects
  40  * which is allocated along with this structure
  41  *
  42  */
  43 struct mtd_concat {
  44         struct mtd_info mtd;
  45         int num_subdev;
  46         struct mtd_info **subdev;
  47 };
  48
  49 /*
  50  * how to calculate the size required for the above structure,
  51  * including the pointer array subdev points to:
  52  */
  53 #define SIZEOF_STRUCT_MTD_CONCAT(num_subdev)    \
  54         ((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *)))
  55
  56 /*
  57  * Given a pointer to the MTD object in the mtd_concat structure,
  58  * we can retrieve the pointer to that structure with this macro.
  59  */
  60 #define CONCAT(x)  ((struct mtd_concat *)(x))
  61
  62 /*
  63  * MTD methods which look up the relevant subdevice, translate the
  64  * effective address and pass through to the subdevice.
  65  */
  66
  67 static int
  68 concat_read(struct mtd_info *mtd, loff_t from, size_t len,
  69             size_t * retlen, u_char * buf)
  70 {
  71         struct mtd_concat *concat = CONCAT(mtd);
  72         int ret = 0, err;
  73         int i;
  74
  75         *retlen = 0;
  76
  77         for (i = 0; i < concat->num_subdev; i++) {
  78                 struct mtd_info *subdev = concat->subdev[i];
  79                 size_t size, retsize;
  80
  81                 if (from >= subdev->size) {
  82                         /* Not destined for this subdev */
  83                         size = 0;
  84                         from -= subdev->size;
  85                         continue;
  86                 }
  87                 if (from + len > subdev->size)
  88                         /* First part goes into this subdev */
  89                         size = subdev->size - from;
  90                 else
  91                         /* Entire transaction goes into this subdev */
  92                         size = len;
  93
  94                 err = subdev->read(subdev, from, size, &retsize, buf);
  95
  96                 /* Save information about bitflips! */
  97                 if (unlikely(err)) {
  98                         if (err == -EBADMSG) {
  99                                 mtd->ecc_stats.failed++;
 100                                 ret = err;
 101                         } else if (err == -EUCLEAN) {
 102                                 mtd->ecc_stats.corrected++;
 103                                 /* Do not overwrite -EBADMSG !! */
 104                                 if (!ret)
 105                                         ret = err;
 106                         } else
 107                                 return err;
 108                 }
 109
 110                 *retlen += retsize;
 111                 len -= size;
 112                 if (len == 0)
 113                         return ret;
 114
 115                 buf += size;
 116                 from = 0;
 117         }
 118         return -EINVAL;
 119 }
 120
 121 static int
 122 concat_write(struct mtd_info *mtd, loff_t to, size_t len,
 123              size_t * retlen, const u_char * buf)
 124 {
 125         struct mtd_concat *concat = CONCAT(mtd);
 126         int err = -EINVAL;
 127         int i;
 128
 129         if (!(mtd->flags & MTD_WRITEABLE))
 130                 return -EROFS;
 131
 132         *retlen = 0;
 133
 134         for (i = 0; i < concat->num_subdev; i++) {
 135                 struct mtd_info *subdev = concat->subdev[i];
 136                 size_t size, retsize;
 137
 138                 if (to >= subdev->size) {
 139                         size = 0;
 140                         to -= subdev->size;
 141                         continue;
 142                 }
 143                 if (to + len > subdev->size)
 144                         size = subdev->size - to;
 145                 else
 146                         size = len;
 147
 148                 if (!(subdev->flags & MTD_WRITEABLE))
 149                         err = -EROFS;
 150                 else
 151                         err = subdev->write(subdev, to, size, &retsize, buf);
 152
 153                 if (err)
 154                         break;
 155
 156                 *retlen += retsize;
 157                 len -= size;
 158                 if (len == 0)
 159                         break;
 160
 161                 err = -EINVAL;
 162                 buf += size;
 163                 to = 0;
 164         }
 165         return err;
 166 }
 167
 168 static int
 169 concat_writev(struct mtd_info *mtd, const struct kvec *vecs,
 170                 unsigned long count, loff_t to, size_t * retlen)
 171 {
 172         struct mtd_concat *concat = CONCAT(mtd);
 173         struct kvec *vecs_copy;
 174         unsigned long entry_low, entry_high;
 175         size_t total_len = 0;
 176         int i;
 177         int err = -EINVAL;
 178
 179         if (!(mtd->flags & MTD_WRITEABLE))
 180                 return -EROFS;
 181
 182         *retlen = 0;
 183
 184         /* Calculate total length of data */
 185         for (i = 0; i < count; i++)
 186                 total_len += vecs[i].iov_len;
 187
 188         /* Do not allow write past end of device */
 189         if ((to + total_len) > mtd->size)
 190                 return -EINVAL;
 191
 192         /* Check alignment */
 193         if (mtd->writesize > 1) {
 194                 uint64_t __to = to;
 195                 if (do_div(__to, mtd->writesize) || (total_len % mtd->writesize))
 196                         return -EINVAL;
 197         }
 198
 199         /* make a copy of vecs */
 200         vecs_copy = kmemdup(vecs, sizeof(struct kvec) * count, GFP_KERNEL);
 201         if (!vecs_copy)
 202                 return -ENOMEM;
 203
 204         entry_low = 0;
 205         for (i = 0; i < concat->num_subdev; i++) {
 206                 struct mtd_info *subdev = concat->subdev[i];
 207                 size_t size, wsize, retsize, old_iov_len;
 208
 209                 if (to >= subdev->size) {
 210                         to -= subdev->size;
 211                         continue;
 212                 }
 213
 214                 size = min_t(uint64_t, total_len, subdev->size - to);
 215                 wsize = size; /* store for future use */
 216
 217                 entry_high = entry_low;
 218                 while (entry_high < count) {
 219                         if (size <= vecs_copy[entry_high].iov_len)
 220                                 break;
 221                         size -= vecs_copy[entry_high++].iov_len;
 222                 }
 223
 224                 old_iov_len = vecs_copy[entry_high].iov_len;
 225                 vecs_copy[entry_high].iov_len = size;
 226
 227                 if (!(subdev->flags & MTD_WRITEABLE))
 228                         err = -EROFS;
 229                 else
 230                         err = subdev->writev(subdev, &vecs_copy[entry_low],
 231                                 entry_high - entry_low + 1, to, &retsize);
 232
 233                 vecs_copy[entry_high].iov_len = old_iov_len - size;
 234                 vecs_copy[entry_high].iov_base += size;
 235
 236                 entry_low = entry_high;
 237
 238                 if (err)
 239                         break;
 240
 241                 *retlen += retsize;
 242                 total_len -= wsize;
 243
 244                 if (total_len == 0)
 245                         break;
 246
 247                 err = -EINVAL;
 248                 to = 0;
 249         }
 250
 251         kfree(vecs_copy);
 252         return err;
 253 }
 254
 255 static int
 256 concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
 257 {
 258         struct mtd_concat *concat = CONCAT(mtd);
 259         struct mtd_oob_ops devops = *ops;
 260         int i, err, ret = 0;
 261
 262         ops->retlen = ops->oobretlen = 0;
 263
 264         for (i = 0; i < concat->num_subdev; i++) {
 265                 struct mtd_info *subdev = concat->subdev[i];
 266
 267                 if (from >= subdev->size) {
 268                         from -= subdev->size;
 269                         continue;
 270                 }
 271
 272                 /* partial read ? */
 273                 if (from + devops.len > subdev->size)
 274                         devops.len = subdev->size - from;
 275
 276                 err = subdev->read_oob(subdev, from, &devops);
 277                 ops->retlen += devops.retlen;
 278                 ops->oobretlen += devops.oobretlen;
 279
 280                 /* Save information about bitflips! */
 281                 if (unlikely(err)) {
 282                         if (err == -EBADMSG) {
 283                                 mtd->ecc_stats.failed++;
 284                                 ret = err;
 285                         } else if (err == -EUCLEAN) {
 286                                 mtd->ecc_stats.corrected++;
 287                                 /* Do not overwrite -EBADMSG !! */
 288                                 if (!ret)
 289                                         ret = err;
 290                         } else
 291                                 return err;
 292                 }
 293
 294                 if (devops.datbuf) {
 295                         devops.len = ops->len - ops->retlen;
 296                         if (!devops.len)
 297                                 return ret;
 298                         devops.datbuf += devops.retlen;
 299                 }
 300                 if (devops.oobbuf) {
 301                         devops.ooblen = ops->ooblen - ops->oobretlen;
 302                         if (!devops.ooblen)
 303                                 return ret;
 304                         devops.oobbuf += ops->oobretlen;
 305                 }
 306
 307                 from = 0;
 308         }
 309         return -EINVAL;
 310 }
 311
 312 static int
 313 concat_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops)
 314 {
 315         struct mtd_concat *concat = CONCAT(mtd);
 316         struct mtd_oob_ops devops = *ops;
 317         int i, err;
 318
 319         if (!(mtd->flags & MTD_WRITEABLE))
 320                 return -EROFS;
 321
 322         ops->retlen = 0;
 323
 324         for (i = 0; i < concat->num_subdev; i++) {
 325                 struct mtd_info *subdev = concat->subdev[i];
 326
 327                 if (to >= subdev->size) {
 328                         to -= subdev->size;
 329                         continue;
 330                 }
 331
 332                 /* partial write ? */
 333                 if (to + devops.len > subdev->size)
 334                         devops.len = subdev->size - to;
 335
 336                 err = subdev->write_oob(subdev, to, &devops);
 337                 ops->retlen += devops.retlen;
 338                 if (err)
 339                         return err;
 340
 341                 if (devops.datbuf) {
 342                         devops.len = ops->len - ops->retlen;
 343                         if (!devops.len)
 344                                 return 0;
 345                         devops.datbuf += devops.retlen;
 346                 }
 347                 if (devops.oobbuf) {
 348                         devops.ooblen = ops->ooblen - ops->oobretlen;
 349                         if (!devops.ooblen)
 350                                 return 0;
 351                         devops.oobbuf += devops.oobretlen;
 352                 }
 353                 to = 0;
 354         }
 355         return -EINVAL;
 356 }
 357
 358 static void concat_erase_callback(struct erase_info *instr)
 359 {
 360         wake_up((wait_queue_head_t *) instr->priv);
 361 }
 362
 363 static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase)
 364 {
 365         int err;
 366         wait_queue_head_t waitq;
 367         DECLARE_WAITQUEUE(wait, current);
 368
 369         /*
 370          * This code was stol^H^H^H^Hinspired by mtdchar.c
 371          */
 372         init_waitqueue_head(&waitq);
 373
 374         erase->mtd = mtd;
 375         erase->callback = concat_erase_callback;
 376         erase->priv = (unsigned long) &waitq;
 377
 378         /*
 379          * FIXME: Allow INTERRUPTIBLE. Which means
 380          * not having the wait_queue head on the stack.
 381          */
 382         err = mtd->erase(mtd, erase);
 383         if (!err) {
 384                 set_current_state(TASK_UNINTERRUPTIBLE);
 385                 add_wait_queue(&waitq, &wait);
 386                 if (erase->state != MTD_ERASE_DONE
 387                     && erase->state != MTD_ERASE_FAILED)
 388                         schedule();
 389                 remove_wait_queue(&waitq, &wait);
 390                 set_current_state(TASK_RUNNING);
 391
 392                 err = (erase->state == MTD_ERASE_FAILED) ? -EIO : 0;
 393         }
 394         return err;
 395 }
 396
 397 static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
 398 {
 399         struct mtd_concat *concat = CONCAT(mtd);
 400         struct mtd_info *subdev;
 401         int i, err;
 402         uint64_t length, offset = 0;
 403         struct erase_info *erase;
 404
 405         if (!(mtd->flags & MTD_WRITEABLE))
 406                 return -EROFS;
 407
 408         if (instr->addr > concat->mtd.size)
 409                 return -EINVAL;
 410
 411         if (instr->len + instr->addr > concat->mtd.size)
 412                 return -EINVAL;
 413
 414         /*
 415          * Check for proper erase block alignment of the to-be-erased area.
 416          * It is easier to do this based on the super device's erase
 417          * region info rather than looking at each particular sub-device
 418          * in turn.
 419          */
 420         if (!concat->mtd.numeraseregions) {
 421                 /* the easy case: device has uniform erase block size */
 422                 if (instr->addr & (concat->mtd.erasesize - 1))
 423                         return -EINVAL;
 424                 if (instr->len & (concat->mtd.erasesize - 1))
 425                         return -EINVAL;
 426         } else {
 427                 /* device has variable erase size */
 428                 struct mtd_erase_region_info *erase_regions =
 429                     concat->mtd.eraseregions;
 430
 431                 /*
 432                  * Find the erase region where the to-be-erased area begins:
 433                  */
 434                 for (i = 0; i < concat->mtd.numeraseregions &&
 435                      instr->addr >= erase_regions[i].offset; i++) ;
 436                 --i;
 437
 438                 /*
 439                  * Now erase_regions[i] is the region in which the
 440                  * to-be-erased area begins. Verify that the starting
 441                  * offset is aligned to this region's erase size:
 442                  */
 443                 if (i < 0 || instr->addr & (erase_regions[i].erasesize - 1))
 444                         return -EINVAL;
 445
 446                 /*
 447                  * now find the erase region where the to-be-erased area ends:
 448                  */
 449                 for (; i < concat->mtd.numeraseregions &&
 450                      (instr->addr + instr->len) >= erase_regions[i].offset;
 451                      ++i) ;
 452                 --i;
 453                 /*
 454                  * check if the ending offset is aligned to this region's erase size
 455                  */
 456                 if (i < 0 || ((instr->addr + instr->len) &
 457                                         (erase_regions[i].erasesize - 1)))
 458                         return -EINVAL;
 459         }
 460
 461         instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
 462
 463         /* make a local copy of instr to avoid modifying the caller's struct */
 464         erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
 465
 466         if (!erase)
 467                 return -ENOMEM;
 468
 469         *erase = *instr;
 470         length = instr->len;
 471
 472         /*
 473          * find the subdevice where the to-be-erased area begins, adjust
 474          * starting offset to be relative to the subdevice start
 475          */
 476         for (i = 0; i < concat->num_subdev; i++) {
 477                 subdev = concat->subdev[i];
 478                 if (subdev->size <= erase->addr) {
 479                         erase->addr -= subdev->size;
 480                         offset += subdev->size;
 481                 } else {
 482                         break;
 483                 }
 484         }
 485
 486         /* must never happen since size limit has been verified above */
 487         BUG_ON(i >= concat->num_subdev);
 488
 489         /* now do the erase: */
 490         err = 0;
 491         for (; length > 0; i++) {
 492                 /* loop for all subdevices affected by this request */
 493                 subdev = concat->subdev[i];     /* get current subdevice */
 494
 495                 /* limit length to subdevice's size: */
 496                 if (erase->addr + length > subdev->size)
 497                         erase->len = subdev->size - erase->addr;
 498                 else
 499                         erase->len = length;
 500
 501                 if (!(subdev->flags & MTD_WRITEABLE)) {
 502                         err = -EROFS;
 503                         break;
 504                 }
 505                 length -= erase->len;
 506                 if ((err = concat_dev_erase(subdev, erase))) {
 507                         /* sanity check: should never happen since
 508                          * block alignment has been checked above */
 509                         BUG_ON(err == -EINVAL);
 510                         if (erase->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
 511                                 instr->fail_addr = erase->fail_addr + offset;
 512                         break;
 513                 }
 514                 /*
 515                  * erase->addr specifies the offset of the area to be
 516                  * erased *within the current subdevice*. It can be
 517                  * non-zero only the first time through this loop, i.e.
 518                  * for the first subdevice where blocks need to be erased.
 519                  * All the following erases must begin at the start of the
 520                  * current subdevice, i.e. at offset zero.
 521                  */
 522                 erase->addr = 0;
 523                 offset += subdev->size;
 524         }
 525         instr->state = erase->state;
 526         kfree(erase);
 527         if (err)
 528                 return err;
 529
 530         if (instr->callback)
 531                 instr->callback(instr);
 532         return 0;
 533 }
 534
 535 static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 536 {
 537         struct mtd_concat *concat = CONCAT(mtd);
 538         int i, err = -EINVAL;
 539
 540         if ((len + ofs) > mtd->size)
 541                 return -EINVAL;
 542
 543         for (i = 0; i < concat->num_subdev; i++) {
 544                 struct mtd_info *subdev = concat->subdev[i];
 545                 uint64_t size;
 546
 547                 if (ofs >= subdev->size) {
 548                         size = 0;
 549                         ofs -= subdev->size;
 550                         continue;
 551                 }
 552                 if (ofs + len > subdev->size)
 553                         size = subdev->size - ofs;
 554                 else
 555                         size = len;
 556
 557                 if (subdev->lock) {
 558                         err = subdev->lock(subdev, ofs, size);
 559                         if (err)
 560                                 break;
 561                 } else
 562                         err = -EOPNOTSUPP;
 563
 564                 len -= size;
 565                 if (len == 0)
 566                         break;
 567
 568                 err = -EINVAL;
 569                 ofs = 0;
 570         }
 571
 572         return err;
 573 }
 574
 575 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 576 {
 577         struct mtd_concat *concat = CONCAT(mtd);
 578         int i, err = 0;
 579
 580         if ((len + ofs) > mtd->size)
 581                 return -EINVAL;
 582
 583         for (i = 0; i < concat->num_subdev; i++) {
 584                 struct mtd_info *subdev = concat->subdev[i];
 585                 uint64_t size;
 586
 587                 if (ofs >= subdev->size) {
 588                         size = 0;
 589                         ofs -= subdev->size;
 590                         continue;
 591                 }
 592                 if (ofs + len > subdev->size)
 593                         size = subdev->size - ofs;
 594                 else
 595                         size = len;
 596
 597                 if (subdev->unlock) {
 598                         err = subdev->unlock(subdev, ofs, size);
 599                         if (err)
 600                                 break;
 601                 } else
 602                         err = -EOPNOTSUPP;
 603
 604                 len -= size;
 605                 if (len == 0)
 606                         break;
 607
 608                 err = -EINVAL;
 609                 ofs = 0;
 610         }
 611
 612         return err;
 613 }
 614
 615 static void concat_sync(struct mtd_info *mtd)
 616 {
 617         struct mtd_concat *concat = CONCAT(mtd);
 618         int i;
 619
 620         for (i = 0; i < concat->num_subdev; i++) {
 621                 struct mtd_info *subdev = concat->subdev[i];
 622                 subdev->sync(subdev);
 623         }
 624 }
 625
 626 static int concat_suspend(struct mtd_info *mtd)
 627 {
 628         struct mtd_concat *concat = CONCAT(mtd);
 629         int i, rc = 0;
 630
 631         for (i = 0; i < concat->num_subdev; i++) {
 632                 struct mtd_info *subdev = concat->subdev[i];
 633                 if ((rc = subdev->suspend(subdev)) < 0)
 634                         return rc;
 635         }
 636         return rc;
 637 }
 638
 639 static void concat_resume(struct mtd_info *mtd)
 640 {
 641         struct mtd_concat *concat = CONCAT(mtd);
 642         int i;
 643
 644         for (i = 0; i < concat->num_subdev; i++) {
 645                 struct mtd_info *subdev = concat->subdev[i];
 646                 subdev->resume(subdev);
 647         }
 648 }
 649
 650 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
 651 {
 652         struct mtd_concat *concat = CONCAT(mtd);
 653         int i, res = 0;
 654
 655         if (!concat->subdev[0]->block_isbad)
 656                 return res;
 657
 658         if (ofs > mtd->size)
 659                 return -EINVAL;
 660
 661         for (i = 0; i < concat->num_subdev; i++) {
 662                 struct mtd_info *subdev = concat->subdev[i];
 663
 664                 if (ofs >= subdev->size) {
 665                         ofs -= subdev->size;
 666                         continue;
 667                 }
 668
 669                 res = subdev->block_isbad(subdev, ofs);
 670                 break;
 671         }
 672
 673         return res;
 674 }
 675
 676 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
 677 {
 678         struct mtd_concat *concat = CONCAT(mtd);
 679         int i, err = -EINVAL;
 680
 681         if (!concat->subdev[0]->block_markbad)
 682                 return 0;
 683
 684         if (ofs > mtd->size)
 685                 return -EINVAL;
 686
 687         for (i = 0; i < concat->num_subdev; i++) {
 688                 struct mtd_info *subdev = concat->subdev[i];
 689
 690                 if (ofs >= subdev->size) {
 691                         ofs -= subdev->size;
 692                         continue;
 693                 }
 694
 695                 err = subdev->block_markbad(subdev, ofs);
 696                 if (!err)
 697                         mtd->ecc_stats.badblocks++;
 698                 break;
 699         }
 700
 701         return err;
 702 }
 703
 704 /*
 705  * try to support NOMMU mmaps on concatenated devices
 706  * - we don't support subdev spanning as we can't guarantee it'll work
 707  */
 708 static unsigned long concat_get_unmapped_area(struct mtd_info *mtd,
 709                                               unsigned long len,
 710                                               unsigned long offset,
 711                                               unsigned long flags)
 712 {
 713         struct mtd_concat *concat = CONCAT(mtd);
 714         int i;
 715
 716         for (i = 0; i < concat->num_subdev; i++) {
 717                 struct mtd_info *subdev = concat->subdev[i];
 718
 719                 if (offset >= subdev->size) {
 720                         offset -= subdev->size;
 721                         continue;
 722                 }
 723
 724                 /* we've found the subdev over which the mapping will reside */
 725                 if (offset + len > subdev->size)
 726                         return (unsigned long) -EINVAL;
 727
 728                 if (subdev->get_unmapped_area)
 729                         return subdev->get_unmapped_area(subdev, len, offset,
 730                                                          flags);
 731
 732                 break;
 733         }
 734
 735         return (unsigned long) -ENOSYS;
 736 }
 737
 738 /*
 739  * This function constructs a virtual MTD device by concatenating
 740  * num_devs MTD devices. A pointer to the new device object is
 741  * stored to *new_dev upon success. This function does _not_
 742  * register any devices: this is the caller's responsibility.
 743  */
 744 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],   /* subdevices to concatenate */
 745                                    int num_devs,        /* number of subdevices      */
 746                                    const char *name)
 747 {                               /* name for the new device   */
 748         int i;
 749         size_t size;
 750         struct mtd_concat *concat;
 751         uint32_t max_erasesize, curr_erasesize;
 752         int num_erase_region;
 753         int max_writebufsize = 0;
 754
 755         printk(KERN_NOTICE "Concatenating MTD devices:\n");
 756         for (i = 0; i < num_devs; i++)
 757                 printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
 758         printk(KERN_NOTICE "into device \"%s\"\n", name);
 759
 760         /* allocate the device structure */
 761         size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
 762         concat = kzalloc(size, GFP_KERNEL);
 763         if (!concat) {
 764                 printk
 765                     ("memory allocation error while creating concatenated device \"%s\"\n",
 766                      name);
 767                 return NULL;
 768         }
 769         concat->subdev = (struct mtd_info **) (concat + 1);
 770
 771         /*
 772          * Set up the new "super" device's MTD object structure, check for
 773          * incompatibilites between the subdevices.
 774          */
 775         concat->mtd.type = subdev[0]->type;
 776         concat->mtd.flags = subdev[0]->flags;
 777         concat->mtd.size = subdev[0]->size;
 778         concat->mtd.erasesize = subdev[0]->erasesize;
 779         concat->mtd.writesize = subdev[0]->writesize;
 780
 781         for (i = 0; i < num_devs; i++)
 782                 if (max_writebufsize < subdev[i]->writebufsize)
 783                         max_writebufsize = subdev[i]->writebufsize;
 784         concat->mtd.writebufsize = max_writebufsize;
 785
 786         concat->mtd.subpage_sft = subdev[0]->subpage_sft;
 787         concat->mtd.oobsize = subdev[0]->oobsize;
 788         concat->mtd.oobavail = subdev[0]->oobavail;
 789         if (subdev[0]->writev)
 790                 concat->mtd.writev = concat_writev;
 791         if (subdev[0]->read_oob)
 792                 concat->mtd.read_oob = concat_read_oob;
 793         if (subdev[0]->write_oob)
 794                 concat->mtd.write_oob = concat_write_oob;
 795         if (subdev[0]->block_isbad)
 796                 concat->mtd.block_isbad = concat_block_isbad;
 797         if (subdev[0]->block_markbad)
 798                 concat->mtd.block_markbad = concat_block_markbad;
 799
 800         concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
 801
 802         concat->mtd.backing_dev_info = subdev[0]->backing_dev_info;
 803
 804         concat->subdev[0] = subdev[0];
 805
 806         for (i = 1; i < num_devs; i++) {
 807                 if (concat->mtd.type != subdev[i]->type) {
 808                         kfree(concat);
 809                         printk("Incompatible device type on \"%s\"\n",
 810                                subdev[i]->name);
 811                         return NULL;
 812                 }
 813                 if (concat->mtd.flags != subdev[i]->flags) {
 814                         /*
 815                          * Expect all flags except MTD_WRITEABLE to be
 816                          * equal on all subdevices.
 817                          */
 818                         if ((concat->mtd.flags ^ subdev[i]->
 819                              flags) & ~MTD_WRITEABLE) {
 820                                 kfree(concat);
 821                                 printk("Incompatible device flags on \"%s\"\n",
 822                                        subdev[i]->name);
 823                                 return NULL;
 824                         } else
 825                                 /* if writeable attribute differs,
 826                                    make super device writeable */
 827                                 concat->mtd.flags |=
 828                                     subdev[i]->flags & MTD_WRITEABLE;
 829                 }
 830
 831                 /* only permit direct mapping if the BDIs are all the same
 832                  * - copy-mapping is still permitted
 833                  */
 834                 if (concat->mtd.backing_dev_info !=
 835                     subdev[i]->backing_dev_info)
 836                         concat->mtd.backing_dev_info =
 837                                 &default_backing_dev_info;
 838
 839                 concat->mtd.size += subdev[i]->size;
 840                 concat->mtd.ecc_stats.badblocks +=
 841                         subdev[i]->ecc_stats.badblocks;
 842                 if (concat->mtd.writesize   !=  subdev[i]->writesize ||
 843                     concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
 844                     concat->mtd.oobsize    !=  subdev[i]->oobsize ||
 845                     !concat->mtd.read_oob  != !subdev[i]->read_oob ||
 846                     !concat->mtd.write_oob != !subdev[i]->write_oob) {
 847                         kfree(concat);
 848                         printk("Incompatible OOB or ECC data on \"%s\"\n",
 849                                subdev[i]->name);
 850                         return NULL;
 851                 }
 852                 concat->subdev[i] = subdev[i];
 853
 854         }
 855
 856         concat->mtd.ecclayout = subdev[0]->ecclayout;
 857
 858         concat->num_subdev = num_devs;
 859         concat->mtd.name = name;
 860
 861         concat->mtd.erase = concat_erase;
 862         concat->mtd.read = concat_read;
 863         concat->mtd.write = concat_write;
 864         concat->mtd.sync = concat_sync;
 865         concat->mtd.lock = concat_lock;
 866         concat->mtd.unlock = concat_unlock;
 867         concat->mtd.suspend = concat_suspend;
 868         concat->mtd.resume = concat_resume;
 869         concat->mtd.get_unmapped_area = concat_get_unmapped_area;
 870
 871         /*
 872          * Combine the erase block size info of the subdevices:
 873          *
 874          * first, walk the map of the new device and see how
 875          * many changes in erase size we have
 876          */
 877         max_erasesize = curr_erasesize = subdev[0]->erasesize;
 878         num_erase_region = 1;
 879         for (i = 0; i < num_devs; i++) {
 880                 if (subdev[i]->numeraseregions == 0) {
 881                         /* current subdevice has uniform erase size */
 882                         if (subdev[i]->erasesize != curr_erasesize) {
 883                                 /* if it differs from the last subdevice's erase size, count it */
 884                                 ++num_erase_region;
 885                                 curr_erasesize = subdev[i]->erasesize;
 886                                 if (curr_erasesize > max_erasesize)
 887                                         max_erasesize = curr_erasesize;
 888                         }
 889                 } else {
 890                         /* current subdevice has variable erase size */
 891                         int j;
 892                         for (j = 0; j < subdev[i]->numeraseregions; j++) {
 893
 894                                 /* walk the list of erase regions, count any changes */
 895                                 if (subdev[i]->eraseregions[j].erasesize !=
 896                                     curr_erasesize) {
 897                                         ++num_erase_region;
 898                                         curr_erasesize =
 899                                             subdev[i]->eraseregions[j].
 900                                             erasesize;
 901                                         if (curr_erasesize > max_erasesize)
 902                                                 max_erasesize = curr_erasesize;
 903                                 }
 904                         }
 905                 }
 906         }
 907
 908         if (num_erase_region == 1) {
 909                 /*
 910                  * All subdevices have the same uniform erase size.
 911                  * This is easy:
 912                  */
 913                 concat->mtd.erasesize = curr_erasesize;
 914                 concat->mtd.numeraseregions = 0;
 915         } else {
 916                 uint64_t tmp64;
 917
 918                 /*
 919                  * erase block size varies across the subdevices: allocate
 920                  * space to store the data describing the variable erase regions
 921                  */
 922                 struct mtd_erase_region_info *erase_region_p;
 923                 uint64_t begin, position;
 924
 925                 concat->mtd.erasesize = max_erasesize;
 926                 concat->mtd.numeraseregions = num_erase_region;
 927                 concat->mtd.eraseregions = erase_region_p =
 928                     kmalloc(num_erase_region *
 929                             sizeof (struct mtd_erase_region_info), GFP_KERNEL);
 930                 if (!erase_region_p) {
 931                         kfree(concat);
 932                         printk
 933                             ("memory allocation error while creating erase region list"
 934                              " for device \"%s\"\n", name);
 935                         return NULL;
 936                 }
 937
 938                 /*
 939                  * walk the map of the new device once more and fill in
 940                  * in erase region info:
 941                  */
 942                 curr_erasesize = subdev[0]->erasesize;
 943                 begin = position = 0;
 944                 for (i = 0; i < num_devs; i++) {
 945                         if (subdev[i]->numeraseregions == 0) {
 946                                 /* current subdevice has uniform erase size */
 947                                 if (subdev[i]->erasesize != curr_erasesize) {
 948                                         /*
 949                                          *  fill in an mtd_erase_region_info structure for the area
 950                                          *  we have walked so far:
 951                                          */
 952                                         erase_region_p->offset = begin;
 953                                         erase_region_p->erasesize =
 954                                             curr_erasesize;
 955                                         tmp64 = position - begin;
 956                                         do_div(tmp64, curr_erasesize);
 957                                         erase_region_p->numblocks = tmp64;
 958                                         begin = position;
 959
 960                                         curr_erasesize = subdev[i]->erasesize;
 961                                         ++erase_region_p;
 962                                 }
 963                                 position += subdev[i]->size;
 964                         } else {
 965                                 /* current subdevice has variable erase size */
 966                                 int j;
 967                                 for (j = 0; j < subdev[i]->numeraseregions; j++) {
 968                                         /* walk the list of erase regions, count any changes */
 969                                         if (subdev[i]->eraseregions[j].
 970                                             erasesize != curr_erasesize) {
 971                                                 erase_region_p->offset = begin;
 972                                                 erase_region_p->erasesize =
 973                                                     curr_erasesize;
 974                                                 tmp64 = position - begin;
 975                                                 do_div(tmp64, curr_erasesize);
 976                                                 erase_region_p->numblocks = tmp64;
 977                                                 begin = position;
 978
 979                                                 curr_erasesize =
 980                                                     subdev[i]->eraseregions[j].
 981                                                     erasesize;
 982                                                 ++erase_region_p;
 983                                         }
 984                                         position +=
 985                                             subdev[i]->eraseregions[j].
 986                                             numblocks * (uint64_t)curr_erasesize;
 987                                 }
 988                         }
 989                 }
 990                 /* Now write the final entry */
 991                 erase_region_p->offset = begin;
 992                 erase_region_p->erasesize = curr_erasesize;
 993                 tmp64 = position - begin;
 994                 do_div(tmp64, curr_erasesize);
 995                 erase_region_p->numblocks = tmp64;
 996         }
 997
 998         return &concat->mtd;
 999 }
1000
1001 /*
1002  * This function destroys an MTD object obtained from concat_mtd_devs()
1003  */
1004
1005 void mtd_concat_destroy(struct mtd_info *mtd)
1006 {
1007         struct mtd_concat *concat = CONCAT(mtd);
1008         if (concat->mtd.numeraseregions)
1009                 kfree(concat->mtd.eraseregions);
1010         kfree(concat);
1011 }
1012
1013 EXPORT_SYMBOL(mtd_concat_create);
1014 EXPORT_SYMBOL(mtd_concat_destroy);
1015
1016 MODULE_LICENSE("GPL");
1017 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
1018 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");