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 = mtd_read(subdev, from, size, &retsize, buf);
  95
  96                 /* Save information about bitflips! */
  97                 if (unlikely(err)) {
  98                         if (mtd_is_eccerr(err)) {
  99                                 mtd->ecc_stats.failed++;
 100                                 ret = err;
 101                         } else if (mtd_is_bitflip(err)) {
 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 = mtd_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 = mtd_writev(subdev, &vecs_copy[entry_low],
 231                                          entry_high - entry_low + 1, to,
 232                                          &retsize);
 233
 234                 vecs_copy[entry_high].iov_len = old_iov_len - size;
 235                 vecs_copy[entry_high].iov_base += size;
 236
 237                 entry_low = entry_high;
 238
 239                 if (err)
 240                         break;
 241
 242                 *retlen += retsize;
 243                 total_len -= wsize;
 244
 245                 if (total_len == 0)
 246                         break;
 247
 248                 err = -EINVAL;
 249                 to = 0;
 250         }
 251
 252         kfree(vecs_copy);
 253         return err;
 254 }
 255
 256 static int
 257 concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
 258 {
 259         struct mtd_concat *concat = CONCAT(mtd);
 260         struct mtd_oob_ops devops = *ops;
 261         int i, err, ret = 0;
 262
 263         ops->retlen = ops->oobretlen = 0;
 264
 265         for (i = 0; i < concat->num_subdev; i++) {
 266                 struct mtd_info *subdev = concat->subdev[i];
 267
 268                 if (from >= subdev->size) {
 269                         from -= subdev->size;
 270                         continue;
 271                 }
 272
 273                 /* partial read ? */
 274                 if (from + devops.len > subdev->size)
 275                         devops.len = subdev->size - from;
 276
 277                 err = mtd_read_oob(subdev, from, &devops);
 278                 ops->retlen += devops.retlen;
 279                 ops->oobretlen += devops.oobretlen;
 280
 281                 /* Save information about bitflips! */
 282                 if (unlikely(err)) {
 283                         if (mtd_is_eccerr(err)) {
 284                                 mtd->ecc_stats.failed++;
 285                                 ret = err;
 286                         } else if (mtd_is_bitflip(err)) {
 287                                 mtd->ecc_stats.corrected++;
 288                                 /* Do not overwrite -EBADMSG !! */
 289                                 if (!ret)
 290                                         ret = err;
 291                         } else
 292                                 return err;
 293                 }
 294
 295                 if (devops.datbuf) {
 296                         devops.len = ops->len - ops->retlen;
 297                         if (!devops.len)
 298                                 return ret;
 299                         devops.datbuf += devops.retlen;
 300                 }
 301                 if (devops.oobbuf) {
 302                         devops.ooblen = ops->ooblen - ops->oobretlen;
 303                         if (!devops.ooblen)
 304                                 return ret;
 305                         devops.oobbuf += ops->oobretlen;
 306                 }
 307
 308                 from = 0;
 309         }
 310         return -EINVAL;
 311 }
 312
 313 static int
 314 concat_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops)
 315 {
 316         struct mtd_concat *concat = CONCAT(mtd);
 317         struct mtd_oob_ops devops = *ops;
 318         int i, err;
 319
 320         if (!(mtd->flags & MTD_WRITEABLE))
 321                 return -EROFS;
 322
 323         ops->retlen = ops->oobretlen = 0;
 324
 325         for (i = 0; i < concat->num_subdev; i++) {
 326                 struct mtd_info *subdev = concat->subdev[i];
 327
 328                 if (to >= subdev->size) {
 329                         to -= subdev->size;
 330                         continue;
 331                 }
 332
 333                 /* partial write ? */
 334                 if (to + devops.len > subdev->size)
 335                         devops.len = subdev->size - to;
 336
 337                 err = mtd_write_oob(subdev, to, &devops);
 338                 ops->retlen += devops.oobretlen;
 339                 if (err)
 340                         return err;
 341
 342                 if (devops.datbuf) {
 343                         devops.len = ops->len - ops->retlen;
 344                         if (!devops.len)
 345                                 return 0;
 346                         devops.datbuf += devops.retlen;
 347                 }
 348                 if (devops.oobbuf) {
 349                         devops.ooblen = ops->ooblen - ops->oobretlen;
 350                         if (!devops.ooblen)
 351                                 return 0;
 352                         devops.oobbuf += devops.oobretlen;
 353                 }
 354                 to = 0;
 355         }
 356         return -EINVAL;
 357 }
 358
 359 static void concat_erase_callback(struct erase_info *instr)
 360 {
 361         wake_up((wait_queue_head_t *) instr->priv);
 362 }
 363
 364 static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase)
 365 {
 366         int err;
 367         wait_queue_head_t waitq;
 368         DECLARE_WAITQUEUE(wait, current);
 369
 370         /*
 371          * This code was stol^H^H^H^Hinspired by mtdchar.c
 372          */
 373         init_waitqueue_head(&waitq);
 374
 375         erase->mtd = mtd;
 376         erase->callback = concat_erase_callback;
 377         erase->priv = (unsigned long) &waitq;
 378
 379         /*
 380          * FIXME: Allow INTERRUPTIBLE. Which means
 381          * not having the wait_queue head on the stack.
 382          */
 383         err = mtd_erase(mtd, erase);
 384         if (!err) {
 385                 set_current_state(TASK_UNINTERRUPTIBLE);
 386                 add_wait_queue(&waitq, &wait);
 387                 if (erase->state != MTD_ERASE_DONE
 388                     && erase->state != MTD_ERASE_FAILED)
 389                         schedule();
 390                 remove_wait_queue(&waitq, &wait);
 391                 set_current_state(TASK_RUNNING);
 392
 393                 err = (erase->state == MTD_ERASE_FAILED) ? -EIO : 0;
 394         }
 395         return err;
 396 }
 397
 398 static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
 399 {
 400         struct mtd_concat *concat = CONCAT(mtd);
 401         struct mtd_info *subdev;
 402         int i, err;
 403         uint64_t length, offset = 0;
 404         struct erase_info *erase;
 405
 406         if (!(mtd->flags & MTD_WRITEABLE))
 407                 return -EROFS;
 408
 409         if (instr->addr > concat->mtd.size)
 410                 return -EINVAL;
 411
 412         if (instr->len + instr->addr > concat->mtd.size)
 413                 return -EINVAL;
 414
 415         /*
 416          * Check for proper erase block alignment of the to-be-erased area.
 417          * It is easier to do this based on the super device's erase
 418          * region info rather than looking at each particular sub-device
 419          * in turn.
 420          */
 421         if (!concat->mtd.numeraseregions) {
 422                 /* the easy case: device has uniform erase block size */
 423                 if (instr->addr & (concat->mtd.erasesize - 1))
 424                         return -EINVAL;
 425                 if (instr->len & (concat->mtd.erasesize - 1))
 426                         return -EINVAL;
 427         } else {
 428                 /* device has variable erase size */
 429                 struct mtd_erase_region_info *erase_regions =
 430                     concat->mtd.eraseregions;
 431
 432                 /*
 433                  * Find the erase region where the to-be-erased area begins:
 434                  */
 435                 for (i = 0; i < concat->mtd.numeraseregions &&
 436                      instr->addr >= erase_regions[i].offset; i++) ;
 437                 --i;
 438
 439                 /*
 440                  * Now erase_regions[i] is the region in which the
 441                  * to-be-erased area begins. Verify that the starting
 442                  * offset is aligned to this region's erase size:
 443                  */
 444                 if (i < 0 || instr->addr & (erase_regions[i].erasesize - 1))
 445                         return -EINVAL;
 446
 447                 /*
 448                  * now find the erase region where the to-be-erased area ends:
 449                  */
 450                 for (; i < concat->mtd.numeraseregions &&
 451                      (instr->addr + instr->len) >= erase_regions[i].offset;
 452                      ++i) ;
 453                 --i;
 454                 /*
 455                  * check if the ending offset is aligned to this region's erase size
 456                  */
 457                 if (i < 0 || ((instr->addr + instr->len) &
 458                                         (erase_regions[i].erasesize - 1)))
 459                         return -EINVAL;
 460         }
 461
 462         instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
 463
 464         /* make a local copy of instr to avoid modifying the caller's struct */
 465         erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
 466
 467         if (!erase)
 468                 return -ENOMEM;
 469
 470         *erase = *instr;
 471         length = instr->len;
 472
 473         /*
 474          * find the subdevice where the to-be-erased area begins, adjust
 475          * starting offset to be relative to the subdevice start
 476          */
 477         for (i = 0; i < concat->num_subdev; i++) {
 478                 subdev = concat->subdev[i];
 479                 if (subdev->size <= erase->addr) {
 480                         erase->addr -= subdev->size;
 481                         offset += subdev->size;
 482                 } else {
 483                         break;
 484                 }
 485         }
 486
 487         /* must never happen since size limit has been verified above */
 488         BUG_ON(i >= concat->num_subdev);
 489
 490         /* now do the erase: */
 491         err = 0;
 492         for (; length > 0; i++) {
 493                 /* loop for all subdevices affected by this request */
 494                 subdev = concat->subdev[i];     /* get current subdevice */
 495
 496                 /* limit length to subdevice's size: */
 497                 if (erase->addr + length > subdev->size)
 498                         erase->len = subdev->size - erase->addr;
 499                 else
 500                         erase->len = length;
 501
 502                 if (!(subdev->flags & MTD_WRITEABLE)) {
 503                         err = -EROFS;
 504                         break;
 505                 }
 506                 length -= erase->len;
 507                 if ((err = concat_dev_erase(subdev, erase))) {
 508                         /* sanity check: should never happen since
 509                          * block alignment has been checked above */
 510                         BUG_ON(err == -EINVAL);
 511                         if (erase->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
 512                                 instr->fail_addr = erase->fail_addr + offset;
 513                         break;
 514                 }
 515                 /*
 516                  * erase->addr specifies the offset of the area to be
 517                  * erased *within the current subdevice*. It can be
 518                  * non-zero only the first time through this loop, i.e.
 519                  * for the first subdevice where blocks need to be erased.
 520                  * All the following erases must begin at the start of the
 521                  * current subdevice, i.e. at offset zero.
 522                  */
 523                 erase->addr = 0;
 524                 offset += subdev->size;
 525         }
 526         instr->state = erase->state;
 527         kfree(erase);
 528         if (err)
 529                 return err;
 530
 531         if (instr->callback)
 532                 instr->callback(instr);
 533         return 0;
 534 }
 535
 536 static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 537 {
 538         struct mtd_concat *concat = CONCAT(mtd);
 539         int i, err = -EINVAL;
 540
 541         if ((len + ofs) > mtd->size)
 542                 return -EINVAL;
 543
 544         for (i = 0; i < concat->num_subdev; i++) {
 545                 struct mtd_info *subdev = concat->subdev[i];
 546                 uint64_t size;
 547
 548                 if (ofs >= subdev->size) {
 549                         size = 0;
 550                         ofs -= subdev->size;
 551                         continue;
 552                 }
 553                 if (ofs + len > subdev->size)
 554                         size = subdev->size - ofs;
 555                 else
 556                         size = len;
 557
 558                 err = mtd_lock(subdev, ofs, size);
 559                 if (err)
 560                         break;
 561
 562                 len -= size;
 563                 if (len == 0)
 564                         break;
 565
 566                 err = -EINVAL;
 567                 ofs = 0;
 568         }
 569
 570         return err;
 571 }
 572
 573 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 574 {
 575         struct mtd_concat *concat = CONCAT(mtd);
 576         int i, err = 0;
 577
 578         if ((len + ofs) > mtd->size)
 579                 return -EINVAL;
 580
 581         for (i = 0; i < concat->num_subdev; i++) {
 582                 struct mtd_info *subdev = concat->subdev[i];
 583                 uint64_t size;
 584
 585                 if (ofs >= subdev->size) {
 586                         size = 0;
 587                         ofs -= subdev->size;
 588                         continue;
 589                 }
 590                 if (ofs + len > subdev->size)
 591                         size = subdev->size - ofs;
 592                 else
 593                         size = len;
 594
 595                 err = mtd_unlock(subdev, ofs, size);
 596                 if (err)
 597                         break;
 598
 599                 len -= size;
 600                 if (len == 0)
 601                         break;
 602
 603                 err = -EINVAL;
 604                 ofs = 0;
 605         }
 606
 607         return err;
 608 }
 609
 610 static void concat_sync(struct mtd_info *mtd)
 611 {
 612         struct mtd_concat *concat = CONCAT(mtd);
 613         int i;
 614
 615         for (i = 0; i < concat->num_subdev; i++) {
 616                 struct mtd_info *subdev = concat->subdev[i];
 617                 mtd_sync(subdev);
 618         }
 619 }
 620
 621 static int concat_suspend(struct mtd_info *mtd)
 622 {
 623         struct mtd_concat *concat = CONCAT(mtd);
 624         int i, rc = 0;
 625
 626         for (i = 0; i < concat->num_subdev; i++) {
 627                 struct mtd_info *subdev = concat->subdev[i];
 628                 if ((rc = mtd_suspend(subdev)) < 0)
 629                         return rc;
 630         }
 631         return rc;
 632 }
 633
 634 static void concat_resume(struct mtd_info *mtd)
 635 {
 636         struct mtd_concat *concat = CONCAT(mtd);
 637         int i;
 638
 639         for (i = 0; i < concat->num_subdev; i++) {
 640                 struct mtd_info *subdev = concat->subdev[i];
 641                 mtd_resume(subdev);
 642         }
 643 }
 644
 645 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
 646 {
 647         struct mtd_concat *concat = CONCAT(mtd);
 648         int i, res = 0;
 649
 650         if (!mtd_can_have_bb(concat->subdev[0]))
 651                 return res;
 652
 653         if (ofs > mtd->size)
 654                 return -EINVAL;
 655
 656         for (i = 0; i < concat->num_subdev; i++) {
 657                 struct mtd_info *subdev = concat->subdev[i];
 658
 659                 if (ofs >= subdev->size) {
 660                         ofs -= subdev->size;
 661                         continue;
 662                 }
 663
 664                 res = mtd_block_isbad(subdev, ofs);
 665                 break;
 666         }
 667
 668         return res;
 669 }
 670
 671 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
 672 {
 673         struct mtd_concat *concat = CONCAT(mtd);
 674         int i, err = -EINVAL;
 675
 676         if (!mtd_can_have_bb(concat->subdev[0]))
 677                 return 0;
 678
 679         if (ofs > mtd->size)
 680                 return -EINVAL;
 681
 682         for (i = 0; i < concat->num_subdev; i++) {
 683                 struct mtd_info *subdev = concat->subdev[i];
 684
 685                 if (ofs >= subdev->size) {
 686                         ofs -= subdev->size;
 687                         continue;
 688                 }
 689
 690                 err = mtd_block_markbad(subdev, ofs);
 691                 if (!err)
 692                         mtd->ecc_stats.badblocks++;
 693                 break;
 694         }
 695
 696         return err;
 697 }
 698
 699 /*
 700  * try to support NOMMU mmaps on concatenated devices
 701  * - we don't support subdev spanning as we can't guarantee it'll work
 702  */
 703 static unsigned long concat_get_unmapped_area(struct mtd_info *mtd,
 704                                               unsigned long len,
 705                                               unsigned long offset,
 706                                               unsigned long flags)
 707 {
 708         struct mtd_concat *concat = CONCAT(mtd);
 709         int i;
 710
 711         for (i = 0; i < concat->num_subdev; i++) {
 712                 struct mtd_info *subdev = concat->subdev[i];
 713
 714                 if (offset >= subdev->size) {
 715                         offset -= subdev->size;
 716                         continue;
 717                 }
 718
 719                 /* we've found the subdev over which the mapping will reside */
 720                 if (offset + len > subdev->size)
 721                         return (unsigned long) -EINVAL;
 722
 723                 return mtd_get_unmapped_area(subdev, len, offset, flags);
 724         }
 725
 726         return (unsigned long) -ENOSYS;
 727 }
 728
 729 /*
 730  * This function constructs a virtual MTD device by concatenating
 731  * num_devs MTD devices. A pointer to the new device object is
 732  * stored to *new_dev upon success. This function does _not_
 733  * register any devices: this is the caller's responsibility.
 734  */
 735 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],   /* subdevices to concatenate */
 736                                    int num_devs,        /* number of subdevices      */
 737                                    const char *name)
 738 {                               /* name for the new device   */
 739         int i;
 740         size_t size;
 741         struct mtd_concat *concat;
 742         uint32_t max_erasesize, curr_erasesize;
 743         int num_erase_region;
 744         int max_writebufsize = 0;
 745
 746         printk(KERN_NOTICE "Concatenating MTD devices:\n");
 747         for (i = 0; i < num_devs; i++)
 748                 printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
 749         printk(KERN_NOTICE "into device \"%s\"\n", name);
 750
 751         /* allocate the device structure */
 752         size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
 753         concat = kzalloc(size, GFP_KERNEL);
 754         if (!concat) {
 755                 printk
 756                     ("memory allocation error while creating concatenated device \"%s\"\n",
 757                      name);
 758                 return NULL;
 759         }
 760         concat->subdev = (struct mtd_info **) (concat + 1);
 761
 762         /*
 763          * Set up the new "super" device's MTD object structure, check for
 764          * incompatibilities between the subdevices.
 765          */
 766         concat->mtd.type = subdev[0]->type;
 767         concat->mtd.flags = subdev[0]->flags;
 768         concat->mtd.size = subdev[0]->size;
 769         concat->mtd.erasesize = subdev[0]->erasesize;
 770         concat->mtd.writesize = subdev[0]->writesize;
 771
 772         for (i = 0; i < num_devs; i++)
 773                 if (max_writebufsize < subdev[i]->writebufsize)
 774                         max_writebufsize = subdev[i]->writebufsize;
 775         concat->mtd.writebufsize = max_writebufsize;
 776
 777         concat->mtd.subpage_sft = subdev[0]->subpage_sft;
 778         concat->mtd.oobsize = subdev[0]->oobsize;
 779         concat->mtd.oobavail = subdev[0]->oobavail;
 780         if (subdev[0]->writev)
 781                 concat->mtd.writev = concat_writev;
 782         if (subdev[0]->read_oob)
 783                 concat->mtd.read_oob = concat_read_oob;
 784         if (subdev[0]->write_oob)
 785                 concat->mtd.write_oob = concat_write_oob;
 786         if (subdev[0]->block_isbad)
 787                 concat->mtd.block_isbad = concat_block_isbad;
 788         if (subdev[0]->block_markbad)
 789                 concat->mtd.block_markbad = concat_block_markbad;
 790
 791         concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
 792
 793         concat->mtd.backing_dev_info = subdev[0]->backing_dev_info;
 794
 795         concat->subdev[0] = subdev[0];
 796
 797         for (i = 1; i < num_devs; i++) {
 798                 if (concat->mtd.type != subdev[i]->type) {
 799                         kfree(concat);
 800                         printk("Incompatible device type on \"%s\"\n",
 801                                subdev[i]->name);
 802                         return NULL;
 803                 }
 804                 if (concat->mtd.flags != subdev[i]->flags) {
 805                         /*
 806                          * Expect all flags except MTD_WRITEABLE to be
 807                          * equal on all subdevices.
 808                          */
 809                         if ((concat->mtd.flags ^ subdev[i]->
 810                              flags) & ~MTD_WRITEABLE) {
 811                                 kfree(concat);
 812                                 printk("Incompatible device flags on \"%s\"\n",
 813                                        subdev[i]->name);
 814                                 return NULL;
 815                         } else
 816                                 /* if writeable attribute differs,
 817                                    make super device writeable */
 818                                 concat->mtd.flags |=
 819                                     subdev[i]->flags & MTD_WRITEABLE;
 820                 }
 821
 822                 /* only permit direct mapping if the BDIs are all the same
 823                  * - copy-mapping is still permitted
 824                  */
 825                 if (concat->mtd.backing_dev_info !=
 826                     subdev[i]->backing_dev_info)
 827                         concat->mtd.backing_dev_info =
 828                                 &default_backing_dev_info;
 829
 830                 concat->mtd.size += subdev[i]->size;
 831                 concat->mtd.ecc_stats.badblocks +=
 832                         subdev[i]->ecc_stats.badblocks;
 833                 if (concat->mtd.writesize   !=  subdev[i]->writesize ||
 834                     concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
 835                     concat->mtd.oobsize    !=  subdev[i]->oobsize ||
 836                     !concat->mtd.read_oob  != !subdev[i]->read_oob ||
 837                     !concat->mtd.write_oob != !subdev[i]->write_oob) {
 838                         kfree(concat);
 839                         printk("Incompatible OOB or ECC data on \"%s\"\n",
 840                                subdev[i]->name);
 841                         return NULL;
 842                 }
 843                 concat->subdev[i] = subdev[i];
 844
 845         }
 846
 847         concat->mtd.ecclayout = subdev[0]->ecclayout;
 848
 849         concat->num_subdev = num_devs;
 850         concat->mtd.name = name;
 851
 852         concat->mtd.erase = concat_erase;
 853         concat->mtd.read = concat_read;
 854         concat->mtd.write = concat_write;
 855         concat->mtd.sync = concat_sync;
 856         concat->mtd.lock = concat_lock;
 857         concat->mtd.unlock = concat_unlock;
 858         concat->mtd.suspend = concat_suspend;
 859         concat->mtd.resume = concat_resume;
 860         concat->mtd.get_unmapped_area = concat_get_unmapped_area;
 861
 862         /*
 863          * Combine the erase block size info of the subdevices:
 864          *
 865          * first, walk the map of the new device and see how
 866          * many changes in erase size we have
 867          */
 868         max_erasesize = curr_erasesize = subdev[0]->erasesize;
 869         num_erase_region = 1;
 870         for (i = 0; i < num_devs; i++) {
 871                 if (subdev[i]->numeraseregions == 0) {
 872                         /* current subdevice has uniform erase size */
 873                         if (subdev[i]->erasesize != curr_erasesize) {
 874                                 /* if it differs from the last subdevice's erase size, count it */
 875                                 ++num_erase_region;
 876                                 curr_erasesize = subdev[i]->erasesize;
 877                                 if (curr_erasesize > max_erasesize)
 878                                         max_erasesize = curr_erasesize;
 879                         }
 880                 } else {
 881                         /* current subdevice has variable erase size */
 882                         int j;
 883                         for (j = 0; j < subdev[i]->numeraseregions; j++) {
 884
 885                                 /* walk the list of erase regions, count any changes */
 886                                 if (subdev[i]->eraseregions[j].erasesize !=
 887                                     curr_erasesize) {
 888                                         ++num_erase_region;
 889                                         curr_erasesize =
 890                                             subdev[i]->eraseregions[j].
 891                                             erasesize;
 892                                         if (curr_erasesize > max_erasesize)
 893                                                 max_erasesize = curr_erasesize;
 894                                 }
 895                         }
 896                 }
 897         }
 898
 899         if (num_erase_region == 1) {
 900                 /*
 901                  * All subdevices have the same uniform erase size.
 902                  * This is easy:
 903                  */
 904                 concat->mtd.erasesize = curr_erasesize;
 905                 concat->mtd.numeraseregions = 0;
 906         } else {
 907                 uint64_t tmp64;
 908
 909                 /*
 910                  * erase block size varies across the subdevices: allocate
 911                  * space to store the data describing the variable erase regions
 912                  */
 913                 struct mtd_erase_region_info *erase_region_p;
 914                 uint64_t begin, position;
 915
 916                 concat->mtd.erasesize = max_erasesize;
 917                 concat->mtd.numeraseregions = num_erase_region;
 918                 concat->mtd.eraseregions = erase_region_p =
 919                     kmalloc(num_erase_region *
 920                             sizeof (struct mtd_erase_region_info), GFP_KERNEL);
 921                 if (!erase_region_p) {
 922                         kfree(concat);
 923                         printk
 924                             ("memory allocation error while creating erase region list"
 925                              " for device \"%s\"\n", name);
 926                         return NULL;
 927                 }
 928
 929                 /*
 930                  * walk the map of the new device once more and fill in
 931                  * in erase region info:
 932                  */
 933                 curr_erasesize = subdev[0]->erasesize;
 934                 begin = position = 0;
 935                 for (i = 0; i < num_devs; i++) {
 936                         if (subdev[i]->numeraseregions == 0) {
 937                                 /* current subdevice has uniform erase size */
 938                                 if (subdev[i]->erasesize != curr_erasesize) {
 939                                         /*
 940                                          *  fill in an mtd_erase_region_info structure for the area
 941                                          *  we have walked so far:
 942                                          */
 943                                         erase_region_p->offset = begin;
 944                                         erase_region_p->erasesize =
 945                                             curr_erasesize;
 946                                         tmp64 = position - begin;
 947                                         do_div(tmp64, curr_erasesize);
 948                                         erase_region_p->numblocks = tmp64;
 949                                         begin = position;
 950
 951                                         curr_erasesize = subdev[i]->erasesize;
 952                                         ++erase_region_p;
 953                                 }
 954                                 position += subdev[i]->size;
 955                         } else {
 956                                 /* current subdevice has variable erase size */
 957                                 int j;
 958                                 for (j = 0; j < subdev[i]->numeraseregions; j++) {
 959                                         /* walk the list of erase regions, count any changes */
 960                                         if (subdev[i]->eraseregions[j].
 961                                             erasesize != curr_erasesize) {
 962                                                 erase_region_p->offset = begin;
 963                                                 erase_region_p->erasesize =
 964                                                     curr_erasesize;
 965                                                 tmp64 = position - begin;
 966                                                 do_div(tmp64, curr_erasesize);
 967                                                 erase_region_p->numblocks = tmp64;
 968                                                 begin = position;
 969
 970                                                 curr_erasesize =
 971                                                     subdev[i]->eraseregions[j].
 972                                                     erasesize;
 973                                                 ++erase_region_p;
 974                                         }
 975                                         position +=
 976                                             subdev[i]->eraseregions[j].
 977                                             numblocks * (uint64_t)curr_erasesize;
 978                                 }
 979                         }
 980                 }
 981                 /* Now write the final entry */
 982                 erase_region_p->offset = begin;
 983                 erase_region_p->erasesize = curr_erasesize;
 984                 tmp64 = position - begin;
 985                 do_div(tmp64, curr_erasesize);
 986                 erase_region_p->numblocks = tmp64;
 987         }
 988
 989         return &concat->mtd;
 990 }
 991
 992 /*
 993  * This function destroys an MTD object obtained from concat_mtd_devs()
 994  */
 995
 996 void mtd_concat_destroy(struct mtd_info *mtd)
 997 {
 998         struct mtd_concat *concat = CONCAT(mtd);
 999         if (concat->mtd.numeraseregions)
1000                 kfree(concat->mtd.eraseregions);
1001         kfree(concat);
1002 }
1003
1004 EXPORT_SYMBOL(mtd_concat_create);
1005 EXPORT_SYMBOL(mtd_concat_destroy);
1006
1007 MODULE_LICENSE("GPL");
1008 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
1009 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");