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