Merge tag 'auxdisplay-for-linus-v5.15-rc1' of git://github.com/ojeda/linux
[linux-2.6-microblaze.git] / drivers / mtd / mtdconcat.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * MTD device concatenation layer
4  *
5  * Copyright © 2002 Robert Kaiser <rkaiser@sysgo.de>
6  * Copyright © 2002-2010 David Woodhouse <dwmw2@infradead.org>
7  *
8  * NAND support by Christian Gan <cgan@iders.ca>
9  */
10
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/sched.h>
15 #include <linux/types.h>
16 #include <linux/backing-dev.h>
17
18 #include <linux/mtd/mtd.h>
19 #include <linux/mtd/concat.h>
20
21 #include <asm/div64.h>
22
23 /*
24  * Our storage structure:
25  * Subdev points to an array of pointers to struct mtd_info objects
26  * which is allocated along with this structure
27  *
28  */
29 struct mtd_concat {
30         struct mtd_info mtd;
31         int num_subdev;
32         struct mtd_info **subdev;
33 };
34
35 /*
36  * how to calculate the size required for the above structure,
37  * including the pointer array subdev points to:
38  */
39 #define SIZEOF_STRUCT_MTD_CONCAT(num_subdev)    \
40         ((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *)))
41
42 /*
43  * Given a pointer to the MTD object in the mtd_concat structure,
44  * we can retrieve the pointer to that structure with this macro.
45  */
46 #define CONCAT(x)  ((struct mtd_concat *)(x))
47
48 /*
49  * MTD methods which look up the relevant subdevice, translate the
50  * effective address and pass through to the subdevice.
51  */
52
53 static int
54 concat_read(struct mtd_info *mtd, loff_t from, size_t len,
55             size_t * retlen, u_char * buf)
56 {
57         struct mtd_concat *concat = CONCAT(mtd);
58         int ret = 0, err;
59         int i;
60
61         for (i = 0; i < concat->num_subdev; i++) {
62                 struct mtd_info *subdev = concat->subdev[i];
63                 size_t size, retsize;
64
65                 if (from >= subdev->size) {
66                         /* Not destined for this subdev */
67                         size = 0;
68                         from -= subdev->size;
69                         continue;
70                 }
71                 if (from + len > subdev->size)
72                         /* First part goes into this subdev */
73                         size = subdev->size - from;
74                 else
75                         /* Entire transaction goes into this subdev */
76                         size = len;
77
78                 err = mtd_read(subdev, from, size, &retsize, buf);
79
80                 /* Save information about bitflips! */
81                 if (unlikely(err)) {
82                         if (mtd_is_eccerr(err)) {
83                                 mtd->ecc_stats.failed++;
84                                 ret = err;
85                         } else if (mtd_is_bitflip(err)) {
86                                 mtd->ecc_stats.corrected++;
87                                 /* Do not overwrite -EBADMSG !! */
88                                 if (!ret)
89                                         ret = err;
90                         } else
91                                 return err;
92                 }
93
94                 *retlen += retsize;
95                 len -= size;
96                 if (len == 0)
97                         return ret;
98
99                 buf += size;
100                 from = 0;
101         }
102         return -EINVAL;
103 }
104
105 static int
106 concat_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
107              size_t * retlen, const u_char * buf)
108 {
109         struct mtd_concat *concat = CONCAT(mtd);
110         int err = -EINVAL;
111         int i;
112         for (i = 0; i < concat->num_subdev; i++) {
113                 struct mtd_info *subdev = concat->subdev[i];
114                 size_t size, retsize;
115
116                 if (to >= subdev->size) {
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                 err = mtd_panic_write(subdev, to, size, &retsize, buf);
126                 if (err == -EOPNOTSUPP) {
127                         printk(KERN_ERR "mtdconcat: Cannot write from panic without panic_write\n");
128                         return err;
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
146 static int
147 concat_write(struct mtd_info *mtd, loff_t to, size_t len,
148              size_t * retlen, const u_char * buf)
149 {
150         struct mtd_concat *concat = CONCAT(mtd);
151         int err = -EINVAL;
152         int i;
153
154         for (i = 0; i < concat->num_subdev; i++) {
155                 struct mtd_info *subdev = concat->subdev[i];
156                 size_t size, retsize;
157
158                 if (to >= subdev->size) {
159                         size = 0;
160                         to -= subdev->size;
161                         continue;
162                 }
163                 if (to + len > subdev->size)
164                         size = subdev->size - to;
165                 else
166                         size = len;
167
168                 err = mtd_write(subdev, to, size, &retsize, buf);
169                 if (err)
170                         break;
171
172                 *retlen += retsize;
173                 len -= size;
174                 if (len == 0)
175                         break;
176
177                 err = -EINVAL;
178                 buf += size;
179                 to = 0;
180         }
181         return err;
182 }
183
184 static int
185 concat_writev(struct mtd_info *mtd, const struct kvec *vecs,
186                 unsigned long count, loff_t to, size_t * retlen)
187 {
188         struct mtd_concat *concat = CONCAT(mtd);
189         struct kvec *vecs_copy;
190         unsigned long entry_low, entry_high;
191         size_t total_len = 0;
192         int i;
193         int err = -EINVAL;
194
195         /* Calculate total length of data */
196         for (i = 0; i < count; i++)
197                 total_len += vecs[i].iov_len;
198
199         /* Check alignment */
200         if (mtd->writesize > 1) {
201                 uint64_t __to = to;
202                 if (do_div(__to, mtd->writesize) || (total_len % mtd->writesize))
203                         return -EINVAL;
204         }
205
206         /* make a copy of vecs */
207         vecs_copy = kmemdup(vecs, sizeof(struct kvec) * count, GFP_KERNEL);
208         if (!vecs_copy)
209                 return -ENOMEM;
210
211         entry_low = 0;
212         for (i = 0; i < concat->num_subdev; i++) {
213                 struct mtd_info *subdev = concat->subdev[i];
214                 size_t size, wsize, retsize, old_iov_len;
215
216                 if (to >= subdev->size) {
217                         to -= subdev->size;
218                         continue;
219                 }
220
221                 size = min_t(uint64_t, total_len, subdev->size - to);
222                 wsize = size; /* store for future use */
223
224                 entry_high = entry_low;
225                 while (entry_high < count) {
226                         if (size <= vecs_copy[entry_high].iov_len)
227                                 break;
228                         size -= vecs_copy[entry_high++].iov_len;
229                 }
230
231                 old_iov_len = vecs_copy[entry_high].iov_len;
232                 vecs_copy[entry_high].iov_len = size;
233
234                 err = mtd_writev(subdev, &vecs_copy[entry_low],
235                                  entry_high - entry_low + 1, to, &retsize);
236
237                 vecs_copy[entry_high].iov_len = old_iov_len - size;
238                 vecs_copy[entry_high].iov_base += size;
239
240                 entry_low = entry_high;
241
242                 if (err)
243                         break;
244
245                 *retlen += retsize;
246                 total_len -= wsize;
247
248                 if (total_len == 0)
249                         break;
250
251                 err = -EINVAL;
252                 to = 0;
253         }
254
255         kfree(vecs_copy);
256         return err;
257 }
258
259 static int
260 concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
261 {
262         struct mtd_concat *concat = CONCAT(mtd);
263         struct mtd_oob_ops devops = *ops;
264         int i, err, ret = 0;
265
266         ops->retlen = ops->oobretlen = 0;
267
268         for (i = 0; i < concat->num_subdev; i++) {
269                 struct mtd_info *subdev = concat->subdev[i];
270
271                 if (from >= subdev->size) {
272                         from -= subdev->size;
273                         continue;
274                 }
275
276                 /* partial read ? */
277                 if (from + devops.len > subdev->size)
278                         devops.len = subdev->size - from;
279
280                 err = mtd_read_oob(subdev, from, &devops);
281                 ops->retlen += devops.retlen;
282                 ops->oobretlen += devops.oobretlen;
283
284                 /* Save information about bitflips! */
285                 if (unlikely(err)) {
286                         if (mtd_is_eccerr(err)) {
287                                 mtd->ecc_stats.failed++;
288                                 ret = err;
289                         } else if (mtd_is_bitflip(err)) {
290                                 mtd->ecc_stats.corrected++;
291                                 /* Do not overwrite -EBADMSG !! */
292                                 if (!ret)
293                                         ret = err;
294                         } else
295                                 return err;
296                 }
297
298                 if (devops.datbuf) {
299                         devops.len = ops->len - ops->retlen;
300                         if (!devops.len)
301                                 return ret;
302                         devops.datbuf += devops.retlen;
303                 }
304                 if (devops.oobbuf) {
305                         devops.ooblen = ops->ooblen - ops->oobretlen;
306                         if (!devops.ooblen)
307                                 return ret;
308                         devops.oobbuf += ops->oobretlen;
309                 }
310
311                 from = 0;
312         }
313         return -EINVAL;
314 }
315
316 static int
317 concat_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops)
318 {
319         struct mtd_concat *concat = CONCAT(mtd);
320         struct mtd_oob_ops devops = *ops;
321         int i, err;
322
323         if (!(mtd->flags & MTD_WRITEABLE))
324                 return -EROFS;
325
326         ops->retlen = ops->oobretlen = 0;
327
328         for (i = 0; i < concat->num_subdev; i++) {
329                 struct mtd_info *subdev = concat->subdev[i];
330
331                 if (to >= subdev->size) {
332                         to -= subdev->size;
333                         continue;
334                 }
335
336                 /* partial write ? */
337                 if (to + devops.len > subdev->size)
338                         devops.len = subdev->size - to;
339
340                 err = mtd_write_oob(subdev, to, &devops);
341                 ops->retlen += devops.retlen;
342                 ops->oobretlen += devops.oobretlen;
343                 if (err)
344                         return err;
345
346                 if (devops.datbuf) {
347                         devops.len = ops->len - ops->retlen;
348                         if (!devops.len)
349                                 return 0;
350                         devops.datbuf += devops.retlen;
351                 }
352                 if (devops.oobbuf) {
353                         devops.ooblen = ops->ooblen - ops->oobretlen;
354                         if (!devops.ooblen)
355                                 return 0;
356                         devops.oobbuf += devops.oobretlen;
357                 }
358                 to = 0;
359         }
360         return -EINVAL;
361 }
362
363 static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
364 {
365         struct mtd_concat *concat = CONCAT(mtd);
366         struct mtd_info *subdev;
367         int i, err;
368         uint64_t length, offset = 0;
369         struct erase_info *erase;
370
371         /*
372          * Check for proper erase block alignment of the to-be-erased area.
373          * It is easier to do this based on the super device's erase
374          * region info rather than looking at each particular sub-device
375          * in turn.
376          */
377         if (!concat->mtd.numeraseregions) {
378                 /* the easy case: device has uniform erase block size */
379                 if (instr->addr & (concat->mtd.erasesize - 1))
380                         return -EINVAL;
381                 if (instr->len & (concat->mtd.erasesize - 1))
382                         return -EINVAL;
383         } else {
384                 /* device has variable erase size */
385                 struct mtd_erase_region_info *erase_regions =
386                     concat->mtd.eraseregions;
387
388                 /*
389                  * Find the erase region where the to-be-erased area begins:
390                  */
391                 for (i = 0; i < concat->mtd.numeraseregions &&
392                      instr->addr >= erase_regions[i].offset; i++) ;
393                 --i;
394
395                 /*
396                  * Now erase_regions[i] is the region in which the
397                  * to-be-erased area begins. Verify that the starting
398                  * offset is aligned to this region's erase size:
399                  */
400                 if (i < 0 || instr->addr & (erase_regions[i].erasesize - 1))
401                         return -EINVAL;
402
403                 /*
404                  * now find the erase region where the to-be-erased area ends:
405                  */
406                 for (; i < concat->mtd.numeraseregions &&
407                      (instr->addr + instr->len) >= erase_regions[i].offset;
408                      ++i) ;
409                 --i;
410                 /*
411                  * check if the ending offset is aligned to this region's erase size
412                  */
413                 if (i < 0 || ((instr->addr + instr->len) &
414                                         (erase_regions[i].erasesize - 1)))
415                         return -EINVAL;
416         }
417
418         /* make a local copy of instr to avoid modifying the caller's struct */
419         erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
420
421         if (!erase)
422                 return -ENOMEM;
423
424         *erase = *instr;
425         length = instr->len;
426
427         /*
428          * find the subdevice where the to-be-erased area begins, adjust
429          * starting offset to be relative to the subdevice start
430          */
431         for (i = 0; i < concat->num_subdev; i++) {
432                 subdev = concat->subdev[i];
433                 if (subdev->size <= erase->addr) {
434                         erase->addr -= subdev->size;
435                         offset += subdev->size;
436                 } else {
437                         break;
438                 }
439         }
440
441         /* must never happen since size limit has been verified above */
442         BUG_ON(i >= concat->num_subdev);
443
444         /* now do the erase: */
445         err = 0;
446         for (; length > 0; i++) {
447                 /* loop for all subdevices affected by this request */
448                 subdev = concat->subdev[i];     /* get current subdevice */
449
450                 /* limit length to subdevice's size: */
451                 if (erase->addr + length > subdev->size)
452                         erase->len = subdev->size - erase->addr;
453                 else
454                         erase->len = length;
455
456                 length -= erase->len;
457                 if ((err = mtd_erase(subdev, erase))) {
458                         /* sanity check: should never happen since
459                          * block alignment has been checked above */
460                         BUG_ON(err == -EINVAL);
461                         if (erase->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
462                                 instr->fail_addr = erase->fail_addr + offset;
463                         break;
464                 }
465                 /*
466                  * erase->addr specifies the offset of the area to be
467                  * erased *within the current subdevice*. It can be
468                  * non-zero only the first time through this loop, i.e.
469                  * for the first subdevice where blocks need to be erased.
470                  * All the following erases must begin at the start of the
471                  * current subdevice, i.e. at offset zero.
472                  */
473                 erase->addr = 0;
474                 offset += subdev->size;
475         }
476         kfree(erase);
477
478         return err;
479 }
480
481 static int concat_xxlock(struct mtd_info *mtd, loff_t ofs, uint64_t len,
482                          bool is_lock)
483 {
484         struct mtd_concat *concat = CONCAT(mtd);
485         int i, err = -EINVAL;
486
487         for (i = 0; i < concat->num_subdev; i++) {
488                 struct mtd_info *subdev = concat->subdev[i];
489                 uint64_t size;
490
491                 if (ofs >= subdev->size) {
492                         size = 0;
493                         ofs -= subdev->size;
494                         continue;
495                 }
496                 if (ofs + len > subdev->size)
497                         size = subdev->size - ofs;
498                 else
499                         size = len;
500
501                 if (is_lock)
502                         err = mtd_lock(subdev, ofs, size);
503                 else
504                         err = mtd_unlock(subdev, ofs, size);
505                 if (err)
506                         break;
507
508                 len -= size;
509                 if (len == 0)
510                         break;
511
512                 err = -EINVAL;
513                 ofs = 0;
514         }
515
516         return err;
517 }
518
519 static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
520 {
521         return concat_xxlock(mtd, ofs, len, true);
522 }
523
524 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
525 {
526         return concat_xxlock(mtd, ofs, len, false);
527 }
528
529 static int concat_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
530 {
531         struct mtd_concat *concat = CONCAT(mtd);
532         int i, err = -EINVAL;
533
534         for (i = 0; i < concat->num_subdev; i++) {
535                 struct mtd_info *subdev = concat->subdev[i];
536
537                 if (ofs >= subdev->size) {
538                         ofs -= subdev->size;
539                         continue;
540                 }
541
542                 if (ofs + len > subdev->size)
543                         break;
544
545                 return mtd_is_locked(subdev, ofs, len);
546         }
547
548         return err;
549 }
550
551 static void concat_sync(struct mtd_info *mtd)
552 {
553         struct mtd_concat *concat = CONCAT(mtd);
554         int i;
555
556         for (i = 0; i < concat->num_subdev; i++) {
557                 struct mtd_info *subdev = concat->subdev[i];
558                 mtd_sync(subdev);
559         }
560 }
561
562 static int concat_suspend(struct mtd_info *mtd)
563 {
564         struct mtd_concat *concat = CONCAT(mtd);
565         int i, rc = 0;
566
567         for (i = 0; i < concat->num_subdev; i++) {
568                 struct mtd_info *subdev = concat->subdev[i];
569                 if ((rc = mtd_suspend(subdev)) < 0)
570                         return rc;
571         }
572         return rc;
573 }
574
575 static void concat_resume(struct mtd_info *mtd)
576 {
577         struct mtd_concat *concat = CONCAT(mtd);
578         int i;
579
580         for (i = 0; i < concat->num_subdev; i++) {
581                 struct mtd_info *subdev = concat->subdev[i];
582                 mtd_resume(subdev);
583         }
584 }
585
586 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
587 {
588         struct mtd_concat *concat = CONCAT(mtd);
589         int i, res = 0;
590
591         if (!mtd_can_have_bb(concat->subdev[0]))
592                 return res;
593
594         for (i = 0; i < concat->num_subdev; i++) {
595                 struct mtd_info *subdev = concat->subdev[i];
596
597                 if (ofs >= subdev->size) {
598                         ofs -= subdev->size;
599                         continue;
600                 }
601
602                 res = mtd_block_isbad(subdev, ofs);
603                 break;
604         }
605
606         return res;
607 }
608
609 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
610 {
611         struct mtd_concat *concat = CONCAT(mtd);
612         int i, err = -EINVAL;
613
614         for (i = 0; i < concat->num_subdev; i++) {
615                 struct mtd_info *subdev = concat->subdev[i];
616
617                 if (ofs >= subdev->size) {
618                         ofs -= subdev->size;
619                         continue;
620                 }
621
622                 err = mtd_block_markbad(subdev, ofs);
623                 if (!err)
624                         mtd->ecc_stats.badblocks++;
625                 break;
626         }
627
628         return err;
629 }
630
631 /*
632  * This function constructs a virtual MTD device by concatenating
633  * num_devs MTD devices. A pointer to the new device object is
634  * stored to *new_dev upon success. This function does _not_
635  * register any devices: this is the caller's responsibility.
636  */
637 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],   /* subdevices to concatenate */
638                                    int num_devs,        /* number of subdevices      */
639                                    const char *name)
640 {                               /* name for the new device   */
641         int i;
642         size_t size;
643         struct mtd_concat *concat;
644         struct mtd_info *subdev_master = NULL;
645         uint32_t max_erasesize, curr_erasesize;
646         int num_erase_region;
647         int max_writebufsize = 0;
648
649         printk(KERN_NOTICE "Concatenating MTD devices:\n");
650         for (i = 0; i < num_devs; i++)
651                 printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
652         printk(KERN_NOTICE "into device \"%s\"\n", name);
653
654         /* allocate the device structure */
655         size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
656         concat = kzalloc(size, GFP_KERNEL);
657         if (!concat) {
658                 printk
659                     ("memory allocation error while creating concatenated device \"%s\"\n",
660                      name);
661                 return NULL;
662         }
663         concat->subdev = (struct mtd_info **) (concat + 1);
664
665         /*
666          * Set up the new "super" device's MTD object structure, check for
667          * incompatibilities between the subdevices.
668          */
669         concat->mtd.type = subdev[0]->type;
670         concat->mtd.flags = subdev[0]->flags;
671         concat->mtd.size = subdev[0]->size;
672         concat->mtd.erasesize = subdev[0]->erasesize;
673         concat->mtd.writesize = subdev[0]->writesize;
674
675         for (i = 0; i < num_devs; i++)
676                 if (max_writebufsize < subdev[i]->writebufsize)
677                         max_writebufsize = subdev[i]->writebufsize;
678         concat->mtd.writebufsize = max_writebufsize;
679
680         concat->mtd.subpage_sft = subdev[0]->subpage_sft;
681         concat->mtd.oobsize = subdev[0]->oobsize;
682         concat->mtd.oobavail = subdev[0]->oobavail;
683
684         subdev_master = mtd_get_master(subdev[0]);
685         if (subdev_master->_writev)
686                 concat->mtd._writev = concat_writev;
687         if (subdev_master->_read_oob)
688                 concat->mtd._read_oob = concat_read_oob;
689         if (subdev_master->_write_oob)
690                 concat->mtd._write_oob = concat_write_oob;
691         if (subdev_master->_block_isbad)
692                 concat->mtd._block_isbad = concat_block_isbad;
693         if (subdev_master->_block_markbad)
694                 concat->mtd._block_markbad = concat_block_markbad;
695         if (subdev_master->_panic_write)
696                 concat->mtd._panic_write = concat_panic_write;
697         if (subdev_master->_read)
698                 concat->mtd._read = concat_read;
699         if (subdev_master->_write)
700                 concat->mtd._write = concat_write;
701
702         concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
703
704         concat->subdev[0] = subdev[0];
705
706         for (i = 1; i < num_devs; i++) {
707                 if (concat->mtd.type != subdev[i]->type) {
708                         kfree(concat);
709                         printk("Incompatible device type on \"%s\"\n",
710                                subdev[i]->name);
711                         return NULL;
712                 }
713                 if (concat->mtd.flags != subdev[i]->flags) {
714                         /*
715                          * Expect all flags except MTD_WRITEABLE to be
716                          * equal on all subdevices.
717                          */
718                         if ((concat->mtd.flags ^ subdev[i]->
719                              flags) & ~MTD_WRITEABLE) {
720                                 kfree(concat);
721                                 printk("Incompatible device flags on \"%s\"\n",
722                                        subdev[i]->name);
723                                 return NULL;
724                         } else
725                                 /* if writeable attribute differs,
726                                    make super device writeable */
727                                 concat->mtd.flags |=
728                                     subdev[i]->flags & MTD_WRITEABLE;
729                 }
730
731                 subdev_master = mtd_get_master(subdev[i]);
732                 concat->mtd.size += subdev[i]->size;
733                 concat->mtd.ecc_stats.badblocks +=
734                         subdev[i]->ecc_stats.badblocks;
735                 if (concat->mtd.writesize   !=  subdev[i]->writesize ||
736                     concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
737                     concat->mtd.oobsize    !=  subdev[i]->oobsize ||
738                     !concat->mtd._read_oob  != !subdev_master->_read_oob ||
739                     !concat->mtd._write_oob != !subdev_master->_write_oob) {
740                         /*
741                          * Check against subdev[i] for data members, because
742                          * subdev's attributes may be different from master
743                          * mtd device. Check against subdev's master mtd
744                          * device for callbacks, because the existence of
745                          * subdev's callbacks is decided by master mtd device.
746                          */
747                         kfree(concat);
748                         printk("Incompatible OOB or ECC data on \"%s\"\n",
749                                subdev[i]->name);
750                         return NULL;
751                 }
752                 concat->subdev[i] = subdev[i];
753
754         }
755
756         mtd_set_ooblayout(&concat->mtd, subdev[0]->ooblayout);
757
758         concat->num_subdev = num_devs;
759         concat->mtd.name = name;
760
761         concat->mtd._erase = concat_erase;
762         concat->mtd._sync = concat_sync;
763         concat->mtd._lock = concat_lock;
764         concat->mtd._unlock = concat_unlock;
765         concat->mtd._is_locked = concat_is_locked;
766         concat->mtd._suspend = concat_suspend;
767         concat->mtd._resume = concat_resume;
768
769         /*
770          * Combine the erase block size info of the subdevices:
771          *
772          * first, walk the map of the new device and see how
773          * many changes in erase size we have
774          */
775         max_erasesize = curr_erasesize = subdev[0]->erasesize;
776         num_erase_region = 1;
777         for (i = 0; i < num_devs; i++) {
778                 if (subdev[i]->numeraseregions == 0) {
779                         /* current subdevice has uniform erase size */
780                         if (subdev[i]->erasesize != curr_erasesize) {
781                                 /* if it differs from the last subdevice's erase size, count it */
782                                 ++num_erase_region;
783                                 curr_erasesize = subdev[i]->erasesize;
784                                 if (curr_erasesize > max_erasesize)
785                                         max_erasesize = curr_erasesize;
786                         }
787                 } else {
788                         /* current subdevice has variable erase size */
789                         int j;
790                         for (j = 0; j < subdev[i]->numeraseregions; j++) {
791
792                                 /* walk the list of erase regions, count any changes */
793                                 if (subdev[i]->eraseregions[j].erasesize !=
794                                     curr_erasesize) {
795                                         ++num_erase_region;
796                                         curr_erasesize =
797                                             subdev[i]->eraseregions[j].
798                                             erasesize;
799                                         if (curr_erasesize > max_erasesize)
800                                                 max_erasesize = curr_erasesize;
801                                 }
802                         }
803                 }
804         }
805
806         if (num_erase_region == 1) {
807                 /*
808                  * All subdevices have the same uniform erase size.
809                  * This is easy:
810                  */
811                 concat->mtd.erasesize = curr_erasesize;
812                 concat->mtd.numeraseregions = 0;
813         } else {
814                 uint64_t tmp64;
815
816                 /*
817                  * erase block size varies across the subdevices: allocate
818                  * space to store the data describing the variable erase regions
819                  */
820                 struct mtd_erase_region_info *erase_region_p;
821                 uint64_t begin, position;
822
823                 concat->mtd.erasesize = max_erasesize;
824                 concat->mtd.numeraseregions = num_erase_region;
825                 concat->mtd.eraseregions = erase_region_p =
826                     kmalloc_array(num_erase_region,
827                                   sizeof(struct mtd_erase_region_info),
828                                   GFP_KERNEL);
829                 if (!erase_region_p) {
830                         kfree(concat);
831                         printk
832                             ("memory allocation error while creating erase region list"
833                              " for device \"%s\"\n", name);
834                         return NULL;
835                 }
836
837                 /*
838                  * walk the map of the new device once more and fill in
839                  * in erase region info:
840                  */
841                 curr_erasesize = subdev[0]->erasesize;
842                 begin = position = 0;
843                 for (i = 0; i < num_devs; i++) {
844                         if (subdev[i]->numeraseregions == 0) {
845                                 /* current subdevice has uniform erase size */
846                                 if (subdev[i]->erasesize != curr_erasesize) {
847                                         /*
848                                          *  fill in an mtd_erase_region_info structure for the area
849                                          *  we have walked so far:
850                                          */
851                                         erase_region_p->offset = begin;
852                                         erase_region_p->erasesize =
853                                             curr_erasesize;
854                                         tmp64 = position - begin;
855                                         do_div(tmp64, curr_erasesize);
856                                         erase_region_p->numblocks = tmp64;
857                                         begin = position;
858
859                                         curr_erasesize = subdev[i]->erasesize;
860                                         ++erase_region_p;
861                                 }
862                                 position += subdev[i]->size;
863                         } else {
864                                 /* current subdevice has variable erase size */
865                                 int j;
866                                 for (j = 0; j < subdev[i]->numeraseregions; j++) {
867                                         /* walk the list of erase regions, count any changes */
868                                         if (subdev[i]->eraseregions[j].
869                                             erasesize != curr_erasesize) {
870                                                 erase_region_p->offset = begin;
871                                                 erase_region_p->erasesize =
872                                                     curr_erasesize;
873                                                 tmp64 = position - begin;
874                                                 do_div(tmp64, curr_erasesize);
875                                                 erase_region_p->numblocks = tmp64;
876                                                 begin = position;
877
878                                                 curr_erasesize =
879                                                     subdev[i]->eraseregions[j].
880                                                     erasesize;
881                                                 ++erase_region_p;
882                                         }
883                                         position +=
884                                             subdev[i]->eraseregions[j].
885                                             numblocks * (uint64_t)curr_erasesize;
886                                 }
887                         }
888                 }
889                 /* Now write the final entry */
890                 erase_region_p->offset = begin;
891                 erase_region_p->erasesize = curr_erasesize;
892                 tmp64 = position - begin;
893                 do_div(tmp64, curr_erasesize);
894                 erase_region_p->numblocks = tmp64;
895         }
896
897         return &concat->mtd;
898 }
899
900 /* Cleans the context obtained from mtd_concat_create() */
901 void mtd_concat_destroy(struct mtd_info *mtd)
902 {
903         struct mtd_concat *concat = CONCAT(mtd);
904         if (concat->mtd.numeraseregions)
905                 kfree(concat->mtd.eraseregions);
906         kfree(concat);
907 }
908
909 EXPORT_SYMBOL(mtd_concat_create);
910 EXPORT_SYMBOL(mtd_concat_destroy);
911
912 MODULE_LICENSE("GPL");
913 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
914 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");