[MTD] Avoid 64-bit division in mtdconcat
[linux-2.6.git] / drivers / mtd / mtdconcat.c
1 /*
2  * MTD device concatenation layer
3  *
4  * (C) 2002 Robert Kaiser <rkaiser@sysgo.de>
5  *
6  * NAND support by Christian Gan <cgan@iders.ca>
7  *
8  * This code is GPL
9  *
10  * $Id: mtdconcat.c,v 1.11 2005/11/07 11:14:20 gleixner Exp $
11  */
12
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <linux/sched.h>
17 #include <linux/types.h>
18
19 #include <linux/mtd/mtd.h>
20 #include <linux/mtd/concat.h>
21
22 #include <asm/div64.h>
23
24 /*
25  * Our storage structure:
26  * Subdev points to an array of pointers to struct mtd_info objects
27  * which is allocated along with this structure
28  *
29  */
30 struct mtd_concat {
31         struct mtd_info mtd;
32         int num_subdev;
33         struct mtd_info **subdev;
34 };
35
36 /*
37  * how to calculate the size required for the above structure,
38  * including the pointer array subdev points to:
39  */
40 #define SIZEOF_STRUCT_MTD_CONCAT(num_subdev)    \
41         ((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *)))
42
43 /*
44  * Given a pointer to the MTD object in the mtd_concat structure,
45  * we can retrieve the pointer to that structure with this macro.
46  */
47 #define CONCAT(x)  ((struct mtd_concat *)(x))
48
49 /*
50  * MTD methods which look up the relevant subdevice, translate the
51  * effective address and pass through to the subdevice.
52  */
53
54 static int
55 concat_read(struct mtd_info *mtd, loff_t from, size_t len,
56             size_t * retlen, u_char * buf)
57 {
58         struct mtd_concat *concat = CONCAT(mtd);
59         int err = -EINVAL;
60         int i;
61
62         *retlen = 0;
63
64         for (i = 0; i < concat->num_subdev; i++) {
65                 struct mtd_info *subdev = concat->subdev[i];
66                 size_t size, retsize;
67
68                 if (from >= subdev->size) {
69                         /* Not destined for this subdev */
70                         size = 0;
71                         from -= subdev->size;
72                         continue;
73                 }
74                 if (from + len > subdev->size)
75                         /* First part goes into this subdev */
76                         size = subdev->size - from;
77                 else
78                         /* Entire transaction goes into this subdev */
79                         size = len;
80
81                 err = subdev->read(subdev, from, size, &retsize, buf);
82
83                 if (err)
84                         break;
85
86                 *retlen += retsize;
87                 len -= size;
88                 if (len == 0)
89                         break;
90
91                 err = -EINVAL;
92                 buf += size;
93                 from = 0;
94         }
95         return err;
96 }
97
98 static int
99 concat_write(struct mtd_info *mtd, loff_t to, size_t len,
100              size_t * retlen, const u_char * buf)
101 {
102         struct mtd_concat *concat = CONCAT(mtd);
103         int err = -EINVAL;
104         int i;
105
106         if (!(mtd->flags & MTD_WRITEABLE))
107                 return -EROFS;
108
109         *retlen = 0;
110
111         for (i = 0; i < concat->num_subdev; i++) {
112                 struct mtd_info *subdev = concat->subdev[i];
113                 size_t size, retsize;
114
115                 if (to >= subdev->size) {
116                         size = 0;
117                         to -= subdev->size;
118                         continue;
119                 }
120                 if (to + len > subdev->size)
121                         size = subdev->size - to;
122                 else
123                         size = len;
124
125                 if (!(subdev->flags & MTD_WRITEABLE))
126                         err = -EROFS;
127                 else
128                         err = subdev->write(subdev, to, size, &retsize, buf);
129
130                 if (err)
131                         break;
132
133                 *retlen += retsize;
134                 len -= size;
135                 if (len == 0)
136                         break;
137
138                 err = -EINVAL;
139                 buf += size;
140                 to = 0;
141         }
142         return err;
143 }
144
145 static int
146 concat_read_ecc(struct mtd_info *mtd, loff_t from, size_t len,
147                 size_t * retlen, u_char * buf, u_char * eccbuf,
148                 struct nand_oobinfo *oobsel)
149 {
150         struct mtd_concat *concat = CONCAT(mtd);
151         int err = -EINVAL;
152         int i;
153
154         *retlen = 0;
155
156         for (i = 0; i < concat->num_subdev; i++) {
157                 struct mtd_info *subdev = concat->subdev[i];
158                 size_t size, retsize;
159
160                 if (from >= subdev->size) {
161                         /* Not destined for this subdev */
162                         size = 0;
163                         from -= subdev->size;
164                         continue;
165                 }
166
167                 if (from + len > subdev->size)
168                         /* First part goes into this subdev */
169                         size = subdev->size - from;
170                 else
171                         /* Entire transaction goes into this subdev */
172                         size = len;
173
174                 if (subdev->read_ecc)
175                         err = subdev->read_ecc(subdev, from, size,
176                                                &retsize, buf, eccbuf, oobsel);
177                 else
178                         err = -EINVAL;
179
180                 if (err)
181                         break;
182
183                 *retlen += retsize;
184                 len -= size;
185                 if (len == 0)
186                         break;
187
188                 err = -EINVAL;
189                 buf += size;
190                 if (eccbuf) {
191                         eccbuf += subdev->oobsize;
192                         /* in nand.c at least, eccbufs are
193                            tagged with 2 (int)eccstatus'; we
194                            must account for these */
195                         eccbuf += 2 * (sizeof (int));
196                 }
197                 from = 0;
198         }
199         return err;
200 }
201
202 static int
203 concat_write_ecc(struct mtd_info *mtd, loff_t to, size_t len,
204                  size_t * retlen, const u_char * buf, u_char * eccbuf,
205                  struct nand_oobinfo *oobsel)
206 {
207         struct mtd_concat *concat = CONCAT(mtd);
208         int err = -EINVAL;
209         int i;
210
211         if (!(mtd->flags & MTD_WRITEABLE))
212                 return -EROFS;
213
214         *retlen = 0;
215
216         for (i = 0; i < concat->num_subdev; i++) {
217                 struct mtd_info *subdev = concat->subdev[i];
218                 size_t size, retsize;
219
220                 if (to >= subdev->size) {
221                         size = 0;
222                         to -= subdev->size;
223                         continue;
224                 }
225                 if (to + len > subdev->size)
226                         size = subdev->size - to;
227                 else
228                         size = len;
229
230                 if (!(subdev->flags & MTD_WRITEABLE))
231                         err = -EROFS;
232                 else if (subdev->write_ecc)
233                         err = subdev->write_ecc(subdev, to, size,
234                                                 &retsize, buf, eccbuf, oobsel);
235                 else
236                         err = -EINVAL;
237
238                 if (err)
239                         break;
240
241                 *retlen += retsize;
242                 len -= size;
243                 if (len == 0)
244                         break;
245
246                 err = -EINVAL;
247                 buf += size;
248                 if (eccbuf)
249                         eccbuf += subdev->oobsize;
250                 to = 0;
251         }
252         return err;
253 }
254
255 static int
256 concat_writev_ecc(struct mtd_info *mtd, const struct kvec *vecs,
257                 unsigned long count, loff_t to, size_t * retlen,
258                 u_char *eccbuf, struct nand_oobinfo *oobsel)
259 {
260         struct mtd_concat *concat = CONCAT(mtd);
261         struct kvec *vecs_copy;
262         unsigned long entry_low, entry_high;
263         size_t total_len = 0;
264         int i;
265         int err = -EINVAL;
266
267         if (!(mtd->flags & MTD_WRITEABLE))
268                 return -EROFS;
269
270         *retlen = 0;
271
272         /* Calculate total length of data */
273         for (i = 0; i < count; i++)
274                 total_len += vecs[i].iov_len;
275
276         /* Do not allow write past end of device */
277         if ((to + total_len) > mtd->size)
278                 return -EINVAL;
279
280         /* Check alignment */
281         if (mtd->oobblock > 1) {
282                 loff_t __to = to;
283                 if (do_div(__to, mtd->oobblock) || (total_len % mtd->oobblock))
284                         return -EINVAL;
285         }
286
287         /* make a copy of vecs */
288         vecs_copy = kmalloc(sizeof(struct kvec) * count, GFP_KERNEL);
289         if (!vecs_copy)
290                 return -ENOMEM;
291         memcpy(vecs_copy, vecs, sizeof(struct kvec) * count);
292
293         entry_low = 0;
294         for (i = 0; i < concat->num_subdev; i++) {
295                 struct mtd_info *subdev = concat->subdev[i];
296                 size_t size, wsize, retsize, old_iov_len;
297
298                 if (to >= subdev->size) {
299                         to -= subdev->size;
300                         continue;
301                 }
302
303                 size = min(total_len, (size_t)(subdev->size - to));
304                 wsize = size; /* store for future use */
305
306                 entry_high = entry_low;
307                 while (entry_high < count) {
308                         if (size <= vecs_copy[entry_high].iov_len)
309                                 break;
310                         size -= vecs_copy[entry_high++].iov_len;
311                 }
312
313                 old_iov_len = vecs_copy[entry_high].iov_len;
314                 vecs_copy[entry_high].iov_len = size;
315
316                 if (!(subdev->flags & MTD_WRITEABLE))
317                         err = -EROFS;
318                 else if (eccbuf)
319                         err = subdev->writev_ecc(subdev, &vecs_copy[entry_low],
320                                 entry_high - entry_low + 1, to, &retsize,
321                                 eccbuf, oobsel);
322                 else
323                         err = subdev->writev(subdev, &vecs_copy[entry_low],
324                                 entry_high - entry_low + 1, to, &retsize);
325
326                 vecs_copy[entry_high].iov_len = old_iov_len - size;
327                 vecs_copy[entry_high].iov_base += size;
328
329                 entry_low = entry_high;
330
331                 if (err)
332                         break;
333
334                 *retlen += retsize;
335                 total_len -= wsize;
336                 if (concat->mtd.type == MTD_NANDFLASH && eccbuf)
337                         eccbuf += mtd->oobavail * (wsize / mtd->oobblock);
338
339                 if (total_len == 0)
340                         break;
341
342                 err = -EINVAL;
343                 to = 0;
344         }
345
346         kfree(vecs_copy);
347         return err;
348 }
349
350 static int
351 concat_writev(struct mtd_info *mtd, const struct kvec *vecs,
352                 unsigned long count, loff_t to, size_t * retlen)
353 {
354         return concat_writev_ecc(mtd, vecs, count, to, retlen, NULL, NULL);
355 }
356
357 static int
358 concat_read_oob(struct mtd_info *mtd, loff_t from, size_t len,
359                 size_t * retlen, u_char * buf)
360 {
361         struct mtd_concat *concat = CONCAT(mtd);
362         int err = -EINVAL;
363         int i;
364
365         *retlen = 0;
366
367         for (i = 0; i < concat->num_subdev; i++) {
368                 struct mtd_info *subdev = concat->subdev[i];
369                 size_t size, retsize;
370
371                 if (from >= subdev->size) {
372                         /* Not destined for this subdev */
373                         size = 0;
374                         from -= subdev->size;
375                         continue;
376                 }
377                 if (from + len > subdev->size)
378                         /* First part goes into this subdev */
379                         size = subdev->size - from;
380                 else
381                         /* Entire transaction goes into this subdev */
382                         size = len;
383
384                 if (subdev->read_oob)
385                         err = subdev->read_oob(subdev, from, size,
386                                                &retsize, buf);
387                 else
388                         err = -EINVAL;
389
390                 if (err)
391                         break;
392
393                 *retlen += retsize;
394                 len -= size;
395                 if (len == 0)
396                         break;
397
398                 err = -EINVAL;
399                 buf += size;
400                 from = 0;
401         }
402         return err;
403 }
404
405 static int
406 concat_write_oob(struct mtd_info *mtd, loff_t to, size_t len,
407                  size_t * retlen, const u_char * buf)
408 {
409         struct mtd_concat *concat = CONCAT(mtd);
410         int err = -EINVAL;
411         int i;
412
413         if (!(mtd->flags & MTD_WRITEABLE))
414                 return -EROFS;
415
416         *retlen = 0;
417
418         for (i = 0; i < concat->num_subdev; i++) {
419                 struct mtd_info *subdev = concat->subdev[i];
420                 size_t size, retsize;
421
422                 if (to >= subdev->size) {
423                         size = 0;
424                         to -= subdev->size;
425                         continue;
426                 }
427                 if (to + len > subdev->size)
428                         size = subdev->size - to;
429                 else
430                         size = len;
431
432                 if (!(subdev->flags & MTD_WRITEABLE))
433                         err = -EROFS;
434                 else if (subdev->write_oob)
435                         err = subdev->write_oob(subdev, to, size, &retsize,
436                                                 buf);
437                 else
438                         err = -EINVAL;
439
440                 if (err)
441                         break;
442
443                 *retlen += retsize;
444                 len -= size;
445                 if (len == 0)
446                         break;
447
448                 err = -EINVAL;
449                 buf += size;
450                 to = 0;
451         }
452         return err;
453 }
454
455 static void concat_erase_callback(struct erase_info *instr)
456 {
457         wake_up((wait_queue_head_t *) instr->priv);
458 }
459
460 static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase)
461 {
462         int err;
463         wait_queue_head_t waitq;
464         DECLARE_WAITQUEUE(wait, current);
465
466         /*
467          * This code was stol^H^H^H^Hinspired by mtdchar.c
468          */
469         init_waitqueue_head(&waitq);
470
471         erase->mtd = mtd;
472         erase->callback = concat_erase_callback;
473         erase->priv = (unsigned long) &waitq;
474
475         /*
476          * FIXME: Allow INTERRUPTIBLE. Which means
477          * not having the wait_queue head on the stack.
478          */
479         err = mtd->erase(mtd, erase);
480         if (!err) {
481                 set_current_state(TASK_UNINTERRUPTIBLE);
482                 add_wait_queue(&waitq, &wait);
483                 if (erase->state != MTD_ERASE_DONE
484                     && erase->state != MTD_ERASE_FAILED)
485                         schedule();
486                 remove_wait_queue(&waitq, &wait);
487                 set_current_state(TASK_RUNNING);
488
489                 err = (erase->state == MTD_ERASE_FAILED) ? -EIO : 0;
490         }
491         return err;
492 }
493
494 static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
495 {
496         struct mtd_concat *concat = CONCAT(mtd);
497         struct mtd_info *subdev;
498         int i, err;
499         u_int32_t length, offset = 0;
500         struct erase_info *erase;
501
502         if (!(mtd->flags & MTD_WRITEABLE))
503                 return -EROFS;
504
505         if (instr->addr > concat->mtd.size)
506                 return -EINVAL;
507
508         if (instr->len + instr->addr > concat->mtd.size)
509                 return -EINVAL;
510
511         /*
512          * Check for proper erase block alignment of the to-be-erased area.
513          * It is easier to do this based on the super device's erase
514          * region info rather than looking at each particular sub-device
515          * in turn.
516          */
517         if (!concat->mtd.numeraseregions) {
518                 /* the easy case: device has uniform erase block size */
519                 if (instr->addr & (concat->mtd.erasesize - 1))
520                         return -EINVAL;
521                 if (instr->len & (concat->mtd.erasesize - 1))
522                         return -EINVAL;
523         } else {
524                 /* device has variable erase size */
525                 struct mtd_erase_region_info *erase_regions =
526                     concat->mtd.eraseregions;
527
528                 /*
529                  * Find the erase region where the to-be-erased area begins:
530                  */
531                 for (i = 0; i < concat->mtd.numeraseregions &&
532                      instr->addr >= erase_regions[i].offset; i++) ;
533                 --i;
534
535                 /*
536                  * Now erase_regions[i] is the region in which the
537                  * to-be-erased area begins. Verify that the starting
538                  * offset is aligned to this region's erase size:
539                  */
540                 if (instr->addr & (erase_regions[i].erasesize - 1))
541                         return -EINVAL;
542
543                 /*
544                  * now find the erase region where the to-be-erased area ends:
545                  */
546                 for (; i < concat->mtd.numeraseregions &&
547                      (instr->addr + instr->len) >= erase_regions[i].offset;
548                      ++i) ;
549                 --i;
550                 /*
551                  * check if the ending offset is aligned to this region's erase size
552                  */
553                 if ((instr->addr + instr->len) & (erase_regions[i].erasesize -
554                                                   1))
555                         return -EINVAL;
556         }
557
558         instr->fail_addr = 0xffffffff;
559
560         /* make a local copy of instr to avoid modifying the caller's struct */
561         erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
562
563         if (!erase)
564                 return -ENOMEM;
565
566         *erase = *instr;
567         length = instr->len;
568
569         /*
570          * find the subdevice where the to-be-erased area begins, adjust
571          * starting offset to be relative to the subdevice start
572          */
573         for (i = 0; i < concat->num_subdev; i++) {
574                 subdev = concat->subdev[i];
575                 if (subdev->size <= erase->addr) {
576                         erase->addr -= subdev->size;
577                         offset += subdev->size;
578                 } else {
579                         break;
580                 }
581         }
582
583         /* must never happen since size limit has been verified above */
584         BUG_ON(i >= concat->num_subdev);
585
586         /* now do the erase: */
587         err = 0;
588         for (; length > 0; i++) {
589                 /* loop for all subdevices affected by this request */
590                 subdev = concat->subdev[i];     /* get current subdevice */
591
592                 /* limit length to subdevice's size: */
593                 if (erase->addr + length > subdev->size)
594                         erase->len = subdev->size - erase->addr;
595                 else
596                         erase->len = length;
597
598                 if (!(subdev->flags & MTD_WRITEABLE)) {
599                         err = -EROFS;
600                         break;
601                 }
602                 length -= erase->len;
603                 if ((err = concat_dev_erase(subdev, erase))) {
604                         /* sanity check: should never happen since
605                          * block alignment has been checked above */
606                         BUG_ON(err == -EINVAL);
607                         if (erase->fail_addr != 0xffffffff)
608                                 instr->fail_addr = erase->fail_addr + offset;
609                         break;
610                 }
611                 /*
612                  * erase->addr specifies the offset of the area to be
613                  * erased *within the current subdevice*. It can be
614                  * non-zero only the first time through this loop, i.e.
615                  * for the first subdevice where blocks need to be erased.
616                  * All the following erases must begin at the start of the
617                  * current subdevice, i.e. at offset zero.
618                  */
619                 erase->addr = 0;
620                 offset += subdev->size;
621         }
622         instr->state = erase->state;
623         kfree(erase);
624         if (err)
625                 return err;
626
627         if (instr->callback)
628                 instr->callback(instr);
629         return 0;
630 }
631
632 static int concat_lock(struct mtd_info *mtd, loff_t ofs, size_t len)
633 {
634         struct mtd_concat *concat = CONCAT(mtd);
635         int i, err = -EINVAL;
636
637         if ((len + ofs) > mtd->size)
638                 return -EINVAL;
639
640         for (i = 0; i < concat->num_subdev; i++) {
641                 struct mtd_info *subdev = concat->subdev[i];
642                 size_t size;
643
644                 if (ofs >= subdev->size) {
645                         size = 0;
646                         ofs -= subdev->size;
647                         continue;
648                 }
649                 if (ofs + len > subdev->size)
650                         size = subdev->size - ofs;
651                 else
652                         size = len;
653
654                 err = subdev->lock(subdev, ofs, size);
655
656                 if (err)
657                         break;
658
659                 len -= size;
660                 if (len == 0)
661                         break;
662
663                 err = -EINVAL;
664                 ofs = 0;
665         }
666
667         return err;
668 }
669
670 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, size_t len)
671 {
672         struct mtd_concat *concat = CONCAT(mtd);
673         int i, err = 0;
674
675         if ((len + ofs) > mtd->size)
676                 return -EINVAL;
677
678         for (i = 0; i < concat->num_subdev; i++) {
679                 struct mtd_info *subdev = concat->subdev[i];
680                 size_t size;
681
682                 if (ofs >= subdev->size) {
683                         size = 0;
684                         ofs -= subdev->size;
685                         continue;
686                 }
687                 if (ofs + len > subdev->size)
688                         size = subdev->size - ofs;
689                 else
690                         size = len;
691
692                 err = subdev->unlock(subdev, ofs, size);
693
694                 if (err)
695                         break;
696
697                 len -= size;
698                 if (len == 0)
699                         break;
700
701                 err = -EINVAL;
702                 ofs = 0;
703         }
704
705         return err;
706 }
707
708 static void concat_sync(struct mtd_info *mtd)
709 {
710         struct mtd_concat *concat = CONCAT(mtd);
711         int i;
712
713         for (i = 0; i < concat->num_subdev; i++) {
714                 struct mtd_info *subdev = concat->subdev[i];
715                 subdev->sync(subdev);
716         }
717 }
718
719 static int concat_suspend(struct mtd_info *mtd)
720 {
721         struct mtd_concat *concat = CONCAT(mtd);
722         int i, rc = 0;
723
724         for (i = 0; i < concat->num_subdev; i++) {
725                 struct mtd_info *subdev = concat->subdev[i];
726                 if ((rc = subdev->suspend(subdev)) < 0)
727                         return rc;
728         }
729         return rc;
730 }
731
732 static void concat_resume(struct mtd_info *mtd)
733 {
734         struct mtd_concat *concat = CONCAT(mtd);
735         int i;
736
737         for (i = 0; i < concat->num_subdev; i++) {
738                 struct mtd_info *subdev = concat->subdev[i];
739                 subdev->resume(subdev);
740         }
741 }
742
743 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
744 {
745         struct mtd_concat *concat = CONCAT(mtd);
746         int i, res = 0;
747
748         if (!concat->subdev[0]->block_isbad)
749                 return res;
750
751         if (ofs > mtd->size)
752                 return -EINVAL;
753
754         for (i = 0; i < concat->num_subdev; i++) {
755                 struct mtd_info *subdev = concat->subdev[i];
756
757                 if (ofs >= subdev->size) {
758                         ofs -= subdev->size;
759                         continue;
760                 }
761
762                 res = subdev->block_isbad(subdev, ofs);
763                 break;
764         }
765
766         return res;
767 }
768
769 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
770 {
771         struct mtd_concat *concat = CONCAT(mtd);
772         int i, err = -EINVAL;
773
774         if (!concat->subdev[0]->block_markbad)
775                 return 0;
776
777         if (ofs > mtd->size)
778                 return -EINVAL;
779
780         for (i = 0; i < concat->num_subdev; i++) {
781                 struct mtd_info *subdev = concat->subdev[i];
782
783                 if (ofs >= subdev->size) {
784                         ofs -= subdev->size;
785                         continue;
786                 }
787
788                 err = subdev->block_markbad(subdev, ofs);
789                 break;
790         }
791
792         return err;
793 }
794
795 /*
796  * This function constructs a virtual MTD device by concatenating
797  * num_devs MTD devices. A pointer to the new device object is
798  * stored to *new_dev upon success. This function does _not_
799  * register any devices: this is the caller's responsibility.
800  */
801 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],   /* subdevices to concatenate */
802                                    int num_devs,        /* number of subdevices      */
803                                    char *name)
804 {                               /* name for the new device   */
805         int i;
806         size_t size;
807         struct mtd_concat *concat;
808         u_int32_t max_erasesize, curr_erasesize;
809         int num_erase_region;
810
811         printk(KERN_NOTICE "Concatenating MTD devices:\n");
812         for (i = 0; i < num_devs; i++)
813                 printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
814         printk(KERN_NOTICE "into device \"%s\"\n", name);
815
816         /* allocate the device structure */
817         size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
818         concat = kmalloc(size, GFP_KERNEL);
819         if (!concat) {
820                 printk
821                     ("memory allocation error while creating concatenated device \"%s\"\n",
822                      name);
823                 return NULL;
824         }
825         memset(concat, 0, size);
826         concat->subdev = (struct mtd_info **) (concat + 1);
827
828         /*
829          * Set up the new "super" device's MTD object structure, check for
830          * incompatibilites between the subdevices.
831          */
832         concat->mtd.type = subdev[0]->type;
833         concat->mtd.flags = subdev[0]->flags;
834         concat->mtd.size = subdev[0]->size;
835         concat->mtd.erasesize = subdev[0]->erasesize;
836         concat->mtd.oobblock = subdev[0]->oobblock;
837         concat->mtd.oobsize = subdev[0]->oobsize;
838         concat->mtd.ecctype = subdev[0]->ecctype;
839         concat->mtd.eccsize = subdev[0]->eccsize;
840         if (subdev[0]->read_ecc)
841                 concat->mtd.read_ecc = concat_read_ecc;
842         if (subdev[0]->write_ecc)
843                 concat->mtd.write_ecc = concat_write_ecc;
844         if (subdev[0]->writev)
845                 concat->mtd.writev = concat_writev;
846         if (subdev[0]->writev_ecc)
847                 concat->mtd.writev_ecc = concat_writev_ecc;
848         if (subdev[0]->read_oob)
849                 concat->mtd.read_oob = concat_read_oob;
850         if (subdev[0]->write_oob)
851                 concat->mtd.write_oob = concat_write_oob;
852         if (subdev[0]->block_isbad)
853                 concat->mtd.block_isbad = concat_block_isbad;
854         if (subdev[0]->block_markbad)
855                 concat->mtd.block_markbad = concat_block_markbad;
856
857         concat->subdev[0] = subdev[0];
858
859         for (i = 1; i < num_devs; i++) {
860                 if (concat->mtd.type != subdev[i]->type) {
861                         kfree(concat);
862                         printk("Incompatible device type on \"%s\"\n",
863                                subdev[i]->name);
864                         return NULL;
865                 }
866                 if (concat->mtd.flags != subdev[i]->flags) {
867                         /*
868                          * Expect all flags except MTD_WRITEABLE to be
869                          * equal on all subdevices.
870                          */
871                         if ((concat->mtd.flags ^ subdev[i]->
872                              flags) & ~MTD_WRITEABLE) {
873                                 kfree(concat);
874                                 printk("Incompatible device flags on \"%s\"\n",
875                                        subdev[i]->name);
876                                 return NULL;
877                         } else
878                                 /* if writeable attribute differs,
879                                    make super device writeable */
880                                 concat->mtd.flags |=
881                                     subdev[i]->flags & MTD_WRITEABLE;
882                 }
883                 concat->mtd.size += subdev[i]->size;
884                 if (concat->mtd.oobblock   !=  subdev[i]->oobblock ||
885                     concat->mtd.oobsize    !=  subdev[i]->oobsize ||
886                     concat->mtd.ecctype    !=  subdev[i]->ecctype ||
887                     concat->mtd.eccsize    !=  subdev[i]->eccsize ||
888                     !concat->mtd.read_ecc  != !subdev[i]->read_ecc ||
889                     !concat->mtd.write_ecc != !subdev[i]->write_ecc ||
890                     !concat->mtd.read_oob  != !subdev[i]->read_oob ||
891                     !concat->mtd.write_oob != !subdev[i]->write_oob) {
892                         kfree(concat);
893                         printk("Incompatible OOB or ECC data on \"%s\"\n",
894                                subdev[i]->name);
895                         return NULL;
896                 }
897                 concat->subdev[i] = subdev[i];
898
899         }
900
901         if(concat->mtd.type == MTD_NANDFLASH)
902                 memcpy(&concat->mtd.oobinfo, &subdev[0]->oobinfo,
903                         sizeof(struct nand_oobinfo));
904
905         concat->num_subdev = num_devs;
906         concat->mtd.name = name;
907
908         concat->mtd.erase = concat_erase;
909         concat->mtd.read = concat_read;
910         concat->mtd.write = concat_write;
911         concat->mtd.sync = concat_sync;
912         concat->mtd.lock = concat_lock;
913         concat->mtd.unlock = concat_unlock;
914         concat->mtd.suspend = concat_suspend;
915         concat->mtd.resume = concat_resume;
916
917         /*
918          * Combine the erase block size info of the subdevices:
919          *
920          * first, walk the map of the new device and see how
921          * many changes in erase size we have
922          */
923         max_erasesize = curr_erasesize = subdev[0]->erasesize;
924         num_erase_region = 1;
925         for (i = 0; i < num_devs; i++) {
926                 if (subdev[i]->numeraseregions == 0) {
927                         /* current subdevice has uniform erase size */
928                         if (subdev[i]->erasesize != curr_erasesize) {
929                                 /* if it differs from the last subdevice's erase size, count it */
930                                 ++num_erase_region;
931                                 curr_erasesize = subdev[i]->erasesize;
932                                 if (curr_erasesize > max_erasesize)
933                                         max_erasesize = curr_erasesize;
934                         }
935                 } else {
936                         /* current subdevice has variable erase size */
937                         int j;
938                         for (j = 0; j < subdev[i]->numeraseregions; j++) {
939
940                                 /* walk the list of erase regions, count any changes */
941                                 if (subdev[i]->eraseregions[j].erasesize !=
942                                     curr_erasesize) {
943                                         ++num_erase_region;
944                                         curr_erasesize =
945                                             subdev[i]->eraseregions[j].
946                                             erasesize;
947                                         if (curr_erasesize > max_erasesize)
948                                                 max_erasesize = curr_erasesize;
949                                 }
950                         }
951                 }
952         }
953
954         if (num_erase_region == 1) {
955                 /*
956                  * All subdevices have the same uniform erase size.
957                  * This is easy:
958                  */
959                 concat->mtd.erasesize = curr_erasesize;
960                 concat->mtd.numeraseregions = 0;
961         } else {
962                 /*
963                  * erase block size varies across the subdevices: allocate
964                  * space to store the data describing the variable erase regions
965                  */
966                 struct mtd_erase_region_info *erase_region_p;
967                 u_int32_t begin, position;
968
969                 concat->mtd.erasesize = max_erasesize;
970                 concat->mtd.numeraseregions = num_erase_region;
971                 concat->mtd.eraseregions = erase_region_p =
972                     kmalloc(num_erase_region *
973                             sizeof (struct mtd_erase_region_info), GFP_KERNEL);
974                 if (!erase_region_p) {
975                         kfree(concat);
976                         printk
977                             ("memory allocation error while creating erase region list"
978                              " for device \"%s\"\n", name);
979                         return NULL;
980                 }
981
982                 /*
983                  * walk the map of the new device once more and fill in
984                  * in erase region info:
985                  */
986                 curr_erasesize = subdev[0]->erasesize;
987                 begin = position = 0;
988                 for (i = 0; i < num_devs; i++) {
989                         if (subdev[i]->numeraseregions == 0) {
990                                 /* current subdevice has uniform erase size */
991                                 if (subdev[i]->erasesize != curr_erasesize) {
992                                         /*
993                                          *  fill in an mtd_erase_region_info structure for the area
994                                          *  we have walked so far:
995                                          */
996                                         erase_region_p->offset = begin;
997                                         erase_region_p->erasesize =
998                                             curr_erasesize;
999                                         erase_region_p->numblocks =
1000                                             (position - begin) / curr_erasesize;
1001                                         begin = position;
1002
1003                                         curr_erasesize = subdev[i]->erasesize;
1004                                         ++erase_region_p;
1005                                 }
1006                                 position += subdev[i]->size;
1007                         } else {
1008                                 /* current subdevice has variable erase size */
1009                                 int j;
1010                                 for (j = 0; j < subdev[i]->numeraseregions; j++) {
1011                                         /* walk the list of erase regions, count any changes */
1012                                         if (subdev[i]->eraseregions[j].
1013                                             erasesize != curr_erasesize) {
1014                                                 erase_region_p->offset = begin;
1015                                                 erase_region_p->erasesize =
1016                                                     curr_erasesize;
1017                                                 erase_region_p->numblocks =
1018                                                     (position -
1019                                                      begin) / curr_erasesize;
1020                                                 begin = position;
1021
1022                                                 curr_erasesize =
1023                                                     subdev[i]->eraseregions[j].
1024                                                     erasesize;
1025                                                 ++erase_region_p;
1026                                         }
1027                                         position +=
1028                                             subdev[i]->eraseregions[j].
1029                                             numblocks * curr_erasesize;
1030                                 }
1031                         }
1032                 }
1033                 /* Now write the final entry */
1034                 erase_region_p->offset = begin;
1035                 erase_region_p->erasesize = curr_erasesize;
1036                 erase_region_p->numblocks = (position - begin) / curr_erasesize;
1037         }
1038
1039         return &concat->mtd;
1040 }
1041
1042 /*
1043  * This function destroys an MTD object obtained from concat_mtd_devs()
1044  */
1045
1046 void mtd_concat_destroy(struct mtd_info *mtd)
1047 {
1048         struct mtd_concat *concat = CONCAT(mtd);
1049         if (concat->mtd.numeraseregions)
1050                 kfree(concat->mtd.eraseregions);
1051         kfree(concat);
1052 }
1053
1054 EXPORT_SYMBOL(mtd_concat_create);
1055 EXPORT_SYMBOL(mtd_concat_destroy);
1056
1057 MODULE_LICENSE("GPL");
1058 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
1059 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");