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         instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
 430
 431         /* make a local copy of instr to avoid modifying the caller's struct */
 432         erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
 433
 434         if (!erase)
 435                 return -ENOMEM;
 436
 437         *erase = *instr;
 438         length = instr->len;
 439
 440         /*
 441          * find the subdevice where the to-be-erased area begins, adjust
 442          * starting offset to be relative to the subdevice start
 443          */
 444         for (i = 0; i < concat->num_subdev; i++) {
 445                 subdev = concat->subdev[i];
 446                 if (subdev->size <= erase->addr) {
 447                         erase->addr -= subdev->size;
 448                         offset += subdev->size;
 449                 } else {
 450                         break;
 451                 }
 452         }
 453
 454         /* must never happen since size limit has been verified above */
 455         BUG_ON(i >= concat->num_subdev);
 456
 457         /* now do the erase: */
 458         err = 0;
 459         for (; length > 0; i++) {
 460                 /* loop for all subdevices affected by this request */
 461                 subdev = concat->subdev[i];     /* get current subdevice */
 462
 463                 /* limit length to subdevice's size: */
 464                 if (erase->addr + length > subdev->size)
 465                         erase->len = subdev->size - erase->addr;
 466                 else
 467                         erase->len = length;
 468
 469                 length -= erase->len;
 470                 if ((err = concat_dev_erase(subdev, erase))) {
 471                         /* sanity check: should never happen since
 472                          * block alignment has been checked above */
 473                         BUG_ON(err == -EINVAL);
 474                         if (erase->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
 475                                 instr->fail_addr = erase->fail_addr + offset;
 476                         break;
 477                 }
 478                 /*
 479                  * erase->addr specifies the offset of the area to be
 480                  * erased *within the current subdevice*. It can be
 481                  * non-zero only the first time through this loop, i.e.
 482                  * for the first subdevice where blocks need to be erased.
 483                  * All the following erases must begin at the start of the
 484                  * current subdevice, i.e. at offset zero.
 485                  */
 486                 erase->addr = 0;
 487                 offset += subdev->size;
 488         }
 489         instr->state = erase->state;
 490         kfree(erase);
 491         if (err)
 492                 return err;
 493
 494         if (instr->callback)
 495                 instr->callback(instr);
 496         return 0;
 497 }
 498
 499 static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 500 {
 501         struct mtd_concat *concat = CONCAT(mtd);
 502         int i, err = -EINVAL;
 503
 504         for (i = 0; i < concat->num_subdev; i++) {
 505                 struct mtd_info *subdev = concat->subdev[i];
 506                 uint64_t size;
 507
 508                 if (ofs >= subdev->size) {
 509                         size = 0;
 510                         ofs -= subdev->size;
 511                         continue;
 512                 }
 513                 if (ofs + len > subdev->size)
 514                         size = subdev->size - ofs;
 515                 else
 516                         size = len;
 517
 518                 err = mtd_lock(subdev, ofs, size);
 519                 if (err)
 520                         break;
 521
 522                 len -= size;
 523                 if (len == 0)
 524                         break;
 525
 526                 err = -EINVAL;
 527                 ofs = 0;
 528         }
 529
 530         return err;
 531 }
 532
 533 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 534 {
 535         struct mtd_concat *concat = CONCAT(mtd);
 536         int i, err = 0;
 537
 538         for (i = 0; i < concat->num_subdev; i++) {
 539                 struct mtd_info *subdev = concat->subdev[i];
 540                 uint64_t size;
 541
 542                 if (ofs >= subdev->size) {
 543                         size = 0;
 544                         ofs -= subdev->size;
 545                         continue;
 546                 }
 547                 if (ofs + len > subdev->size)
 548                         size = subdev->size - ofs;
 549                 else
 550                         size = len;
 551
 552                 err = mtd_unlock(subdev, ofs, size);
 553                 if (err)
 554                         break;
 555
 556                 len -= size;
 557                 if (len == 0)
 558                         break;
 559
 560                 err = -EINVAL;
 561                 ofs = 0;
 562         }
 563
 564         return err;
 565 }
 566
 567 static void concat_sync(struct mtd_info *mtd)
 568 {
 569         struct mtd_concat *concat = CONCAT(mtd);
 570         int i;
 571
 572         for (i = 0; i < concat->num_subdev; i++) {
 573                 struct mtd_info *subdev = concat->subdev[i];
 574                 mtd_sync(subdev);
 575         }
 576 }
 577
 578 static int concat_suspend(struct mtd_info *mtd)
 579 {
 580         struct mtd_concat *concat = CONCAT(mtd);
 581         int i, rc = 0;
 582
 583         for (i = 0; i < concat->num_subdev; i++) {
 584                 struct mtd_info *subdev = concat->subdev[i];
 585                 if ((rc = mtd_suspend(subdev)) < 0)
 586                         return rc;
 587         }
 588         return rc;
 589 }
 590
 591 static void concat_resume(struct mtd_info *mtd)
 592 {
 593         struct mtd_concat *concat = CONCAT(mtd);
 594         int i;
 595
 596         for (i = 0; i < concat->num_subdev; i++) {
 597                 struct mtd_info *subdev = concat->subdev[i];
 598                 mtd_resume(subdev);
 599         }
 600 }
 601
 602 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
 603 {
 604         struct mtd_concat *concat = CONCAT(mtd);
 605         int i, res = 0;
 606
 607         if (!mtd_can_have_bb(concat->subdev[0]))
 608                 return res;
 609
 610         for (i = 0; i < concat->num_subdev; i++) {
 611                 struct mtd_info *subdev = concat->subdev[i];
 612
 613                 if (ofs >= subdev->size) {
 614                         ofs -= subdev->size;
 615                         continue;
 616                 }
 617
 618                 res = mtd_block_isbad(subdev, ofs);
 619                 break;
 620         }
 621
 622         return res;
 623 }
 624
 625 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
 626 {
 627         struct mtd_concat *concat = CONCAT(mtd);
 628         int i, err = -EINVAL;
 629
 630         for (i = 0; i < concat->num_subdev; i++) {
 631                 struct mtd_info *subdev = concat->subdev[i];
 632
 633                 if (ofs >= subdev->size) {
 634                         ofs -= subdev->size;
 635                         continue;
 636                 }
 637
 638                 err = mtd_block_markbad(subdev, ofs);
 639                 if (!err)
 640                         mtd->ecc_stats.badblocks++;
 641                 break;
 642         }
 643
 644         return err;
 645 }
 646
 647 /*
 648  * try to support NOMMU mmaps on concatenated devices
 649  * - we don't support subdev spanning as we can't guarantee it'll work
 650  */
 651 static unsigned long concat_get_unmapped_area(struct mtd_info *mtd,
 652                                               unsigned long len,
 653                                               unsigned long offset,
 654                                               unsigned long flags)
 655 {
 656         struct mtd_concat *concat = CONCAT(mtd);
 657         int i;
 658
 659         for (i = 0; i < concat->num_subdev; i++) {
 660                 struct mtd_info *subdev = concat->subdev[i];
 661
 662                 if (offset >= subdev->size) {
 663                         offset -= subdev->size;
 664                         continue;
 665                 }
 666
 667                 return mtd_get_unmapped_area(subdev, len, offset, flags);
 668         }
 669
 670         return (unsigned long) -ENOSYS;
 671 }
 672
 673 /*
 674  * This function constructs a virtual MTD device by concatenating
 675  * num_devs MTD devices. A pointer to the new device object is
 676  * stored to *new_dev upon success. This function does _not_
 677  * register any devices: this is the caller's responsibility.
 678  */
 679 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],   /* subdevices to concatenate */
 680                                    int num_devs,        /* number of subdevices      */
 681                                    const char *name)
 682 {                               /* name for the new device   */
 683         int i;
 684         size_t size;
 685         struct mtd_concat *concat;
 686         uint32_t max_erasesize, curr_erasesize;
 687         int num_erase_region;
 688         int max_writebufsize = 0;
 689
 690         printk(KERN_NOTICE "Concatenating MTD devices:\n");
 691         for (i = 0; i < num_devs; i++)
 692                 printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
 693         printk(KERN_NOTICE "into device \"%s\"\n", name);
 694
 695         /* allocate the device structure */
 696         size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
 697         concat = kzalloc(size, GFP_KERNEL);
 698         if (!concat) {
 699                 printk
 700                     ("memory allocation error while creating concatenated device \"%s\"\n",
 701                      name);
 702                 return NULL;
 703         }
 704         concat->subdev = (struct mtd_info **) (concat + 1);
 705
 706         /*
 707          * Set up the new "super" device's MTD object structure, check for
 708          * incompatibilities between the subdevices.
 709          */
 710         concat->mtd.type = subdev[0]->type;
 711         concat->mtd.flags = subdev[0]->flags;
 712         concat->mtd.size = subdev[0]->size;
 713         concat->mtd.erasesize = subdev[0]->erasesize;
 714         concat->mtd.writesize = subdev[0]->writesize;
 715
 716         for (i = 0; i < num_devs; i++)
 717                 if (max_writebufsize < subdev[i]->writebufsize)
 718                         max_writebufsize = subdev[i]->writebufsize;
 719         concat->mtd.writebufsize = max_writebufsize;
 720
 721         concat->mtd.subpage_sft = subdev[0]->subpage_sft;
 722         concat->mtd.oobsize = subdev[0]->oobsize;
 723         concat->mtd.oobavail = subdev[0]->oobavail;
 724         if (subdev[0]->_writev)
 725                 concat->mtd._writev = concat_writev;
 726         if (subdev[0]->_read_oob)
 727                 concat->mtd._read_oob = concat_read_oob;
 728         if (subdev[0]->_write_oob)
 729                 concat->mtd._write_oob = concat_write_oob;
 730         if (subdev[0]->_block_isbad)
 731                 concat->mtd._block_isbad = concat_block_isbad;
 732         if (subdev[0]->_block_markbad)
 733                 concat->mtd._block_markbad = concat_block_markbad;
 734
 735         concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
 736
 737         concat->mtd.backing_dev_info = subdev[0]->backing_dev_info;
 738
 739         concat->subdev[0] = subdev[0];
 740
 741         for (i = 1; i < num_devs; i++) {
 742                 if (concat->mtd.type != subdev[i]->type) {
 743                         kfree(concat);
 744                         printk("Incompatible device type on \"%s\"\n",
 745                                subdev[i]->name);
 746                         return NULL;
 747                 }
 748                 if (concat->mtd.flags != subdev[i]->flags) {
 749                         /*
 750                          * Expect all flags except MTD_WRITEABLE to be
 751                          * equal on all subdevices.
 752                          */
 753                         if ((concat->mtd.flags ^ subdev[i]->
 754                              flags) & ~MTD_WRITEABLE) {
 755                                 kfree(concat);
 756                                 printk("Incompatible device flags on \"%s\"\n",
 757                                        subdev[i]->name);
 758                                 return NULL;
 759                         } else
 760                                 /* if writeable attribute differs,
 761                                    make super device writeable */
 762                                 concat->mtd.flags |=
 763                                     subdev[i]->flags & MTD_WRITEABLE;
 764                 }
 765
 766                 /* only permit direct mapping if the BDIs are all the same
 767                  * - copy-mapping is still permitted
 768                  */
 769                 if (concat->mtd.backing_dev_info !=
 770                     subdev[i]->backing_dev_info)
 771                         concat->mtd.backing_dev_info =
 772                                 &default_backing_dev_info;
 773
 774                 concat->mtd.size += subdev[i]->size;
 775                 concat->mtd.ecc_stats.badblocks +=
 776                         subdev[i]->ecc_stats.badblocks;
 777                 if (concat->mtd.writesize   !=  subdev[i]->writesize ||
 778                     concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
 779                     concat->mtd.oobsize    !=  subdev[i]->oobsize ||
 780                     !concat->mtd._read_oob  != !subdev[i]->_read_oob ||
 781                     !concat->mtd._write_oob != !subdev[i]->_write_oob) {
 782                         kfree(concat);
 783                         printk("Incompatible OOB or ECC data on \"%s\"\n",
 784                                subdev[i]->name);
 785                         return NULL;
 786                 }
 787                 concat->subdev[i] = subdev[i];
 788
 789         }
 790
 791         concat->mtd.ecclayout = subdev[0]->ecclayout;
 792
 793         concat->num_subdev = num_devs;
 794         concat->mtd.name = name;
 795
 796         concat->mtd._erase = concat_erase;
 797         concat->mtd._read = concat_read;
 798         concat->mtd._write = concat_write;
 799         concat->mtd._sync = concat_sync;
 800         concat->mtd._lock = concat_lock;
 801         concat->mtd._unlock = concat_unlock;
 802         concat->mtd._suspend = concat_suspend;
 803         concat->mtd._resume = concat_resume;
 804         concat->mtd._get_unmapped_area = concat_get_unmapped_area;
 805
 806         /*
 807          * Combine the erase block size info of the subdevices:
 808          *
 809          * first, walk the map of the new device and see how
 810          * many changes in erase size we have
 811          */
 812         max_erasesize = curr_erasesize = subdev[0]->erasesize;
 813         num_erase_region = 1;
 814         for (i = 0; i < num_devs; i++) {
 815                 if (subdev[i]->numeraseregions == 0) {
 816                         /* current subdevice has uniform erase size */
 817                         if (subdev[i]->erasesize != curr_erasesize) {
 818                                 /* if it differs from the last subdevice's erase size, count it */
 819                                 ++num_erase_region;
 820                                 curr_erasesize = subdev[i]->erasesize;
 821                                 if (curr_erasesize > max_erasesize)
 822                                         max_erasesize = curr_erasesize;
 823                         }
 824                 } else {
 825                         /* current subdevice has variable erase size */
 826                         int j;
 827                         for (j = 0; j < subdev[i]->numeraseregions; j++) {
 828
 829                                 /* walk the list of erase regions, count any changes */
 830                                 if (subdev[i]->eraseregions[j].erasesize !=
 831                                     curr_erasesize) {
 832                                         ++num_erase_region;
 833                                         curr_erasesize =
 834                                             subdev[i]->eraseregions[j].
 835                                             erasesize;
 836                                         if (curr_erasesize > max_erasesize)
 837                                                 max_erasesize = curr_erasesize;
 838                                 }
 839                         }
 840                 }
 841         }
 842
 843         if (num_erase_region == 1) {
 844                 /*
 845                  * All subdevices have the same uniform erase size.
 846                  * This is easy:
 847                  */
 848                 concat->mtd.erasesize = curr_erasesize;
 849                 concat->mtd.numeraseregions = 0;
 850         } else {
 851                 uint64_t tmp64;
 852
 853                 /*
 854                  * erase block size varies across the subdevices: allocate
 855                  * space to store the data describing the variable erase regions
 856                  */
 857                 struct mtd_erase_region_info *erase_region_p;
 858                 uint64_t begin, position;
 859
 860                 concat->mtd.erasesize = max_erasesize;
 861                 concat->mtd.numeraseregions = num_erase_region;
 862                 concat->mtd.eraseregions = erase_region_p =
 863                     kmalloc(num_erase_region *
 864                             sizeof (struct mtd_erase_region_info), GFP_KERNEL);
 865                 if (!erase_region_p) {
 866                         kfree(concat);
 867                         printk
 868                             ("memory allocation error while creating erase region list"
 869                              " for device \"%s\"\n", name);
 870                         return NULL;
 871                 }
 872
 873                 /*
 874                  * walk the map of the new device once more and fill in
 875                  * in erase region info:
 876                  */
 877                 curr_erasesize = subdev[0]->erasesize;
 878                 begin = position = 0;
 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                                         /*
 884                                          *  fill in an mtd_erase_region_info structure for the area
 885                                          *  we have walked so far:
 886                                          */
 887                                         erase_region_p->offset = begin;
 888                                         erase_region_p->erasesize =
 889                                             curr_erasesize;
 890                                         tmp64 = position - begin;
 891                                         do_div(tmp64, curr_erasesize);
 892                                         erase_region_p->numblocks = tmp64;
 893                                         begin = position;
 894
 895                                         curr_erasesize = subdev[i]->erasesize;
 896                                         ++erase_region_p;
 897                                 }
 898                                 position += subdev[i]->size;
 899                         } else {
 900                                 /* current subdevice has variable erase size */
 901                                 int j;
 902                                 for (j = 0; j < subdev[i]->numeraseregions; j++) {
 903                                         /* walk the list of erase regions, count any changes */
 904                                         if (subdev[i]->eraseregions[j].
 905                                             erasesize != curr_erasesize) {
 906                                                 erase_region_p->offset = begin;
 907                                                 erase_region_p->erasesize =
 908                                                     curr_erasesize;
 909                                                 tmp64 = position - begin;
 910                                                 do_div(tmp64, curr_erasesize);
 911                                                 erase_region_p->numblocks = tmp64;
 912                                                 begin = position;
 913
 914                                                 curr_erasesize =
 915                                                     subdev[i]->eraseregions[j].
 916                                                     erasesize;
 917                                                 ++erase_region_p;
 918                                         }
 919                                         position +=
 920                                             subdev[i]->eraseregions[j].
 921                                             numblocks * (uint64_t)curr_erasesize;
 922                                 }
 923                         }
 924                 }
 925                 /* Now write the final entry */
 926                 erase_region_p->offset = begin;
 927                 erase_region_p->erasesize = curr_erasesize;
 928                 tmp64 = position - begin;
 929                 do_div(tmp64, curr_erasesize);
 930                 erase_region_p->numblocks = tmp64;
 931         }
 932
 933         return &concat->mtd;
 934 }
 935
 936 /*
 937  * This function destroys an MTD object obtained from concat_mtd_devs()
 938  */
 939
 940 void mtd_concat_destroy(struct mtd_info *mtd)
 941 {
 942         struct mtd_concat *concat = CONCAT(mtd);
 943         if (concat->mtd.numeraseregions)
 944                 kfree(concat->mtd.eraseregions);
 945         kfree(concat);
 946 }
 947
 948 EXPORT_SYMBOL(mtd_concat_create);
 949 EXPORT_SYMBOL(mtd_concat_destroy);
 950
 951 MODULE_LICENSE("GPL");
 952 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
 953 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");