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