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
concat_read(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,u_char * buf)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
concat_write(struct mtd_info * mtd,loff_t to,size_t len,size_t * retlen,const u_char * buf)106 concat_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
113 for (i = 0; i < concat->num_subdev; i++) {
114 struct mtd_info *subdev = concat->subdev[i];
115 size_t size, retsize;
116
117 if (to >= subdev->size) {
118 size = 0;
119 to -= subdev->size;
120 continue;
121 }
122 if (to + len > subdev->size)
123 size = subdev->size - to;
124 else
125 size = len;
126
127 err = mtd_write(subdev, to, size, &retsize, buf);
128 if (err)
129 break;
130
131 *retlen += retsize;
132 len -= size;
133 if (len == 0)
134 break;
135
136 err = -EINVAL;
137 buf += size;
138 to = 0;
139 }
140 return err;
141 }
142
143 static int
concat_writev(struct mtd_info * mtd,const struct kvec * vecs,unsigned long count,loff_t to,size_t * retlen)144 concat_writev(struct mtd_info *mtd, const struct kvec *vecs,
145 unsigned long count, loff_t to, size_t * retlen)
146 {
147 struct mtd_concat *concat = CONCAT(mtd);
148 struct kvec *vecs_copy;
149 unsigned long entry_low, entry_high;
150 size_t total_len = 0;
151 int i;
152 int err = -EINVAL;
153
154 /* Calculate total length of data */
155 for (i = 0; i < count; i++)
156 total_len += vecs[i].iov_len;
157
158 /* Check alignment */
159 if (mtd->writesize > 1) {
160 uint64_t __to = to;
161 if (do_div(__to, mtd->writesize) || (total_len % mtd->writesize))
162 return -EINVAL;
163 }
164
165 /* make a copy of vecs */
166 vecs_copy = kmemdup(vecs, sizeof(struct kvec) * count, GFP_KERNEL);
167 if (!vecs_copy)
168 return -ENOMEM;
169
170 entry_low = 0;
171 for (i = 0; i < concat->num_subdev; i++) {
172 struct mtd_info *subdev = concat->subdev[i];
173 size_t size, wsize, retsize, old_iov_len;
174
175 if (to >= subdev->size) {
176 to -= subdev->size;
177 continue;
178 }
179
180 size = min_t(uint64_t, total_len, subdev->size - to);
181 wsize = size; /* store for future use */
182
183 entry_high = entry_low;
184 while (entry_high < count) {
185 if (size <= vecs_copy[entry_high].iov_len)
186 break;
187 size -= vecs_copy[entry_high++].iov_len;
188 }
189
190 old_iov_len = vecs_copy[entry_high].iov_len;
191 vecs_copy[entry_high].iov_len = size;
192
193 err = mtd_writev(subdev, &vecs_copy[entry_low],
194 entry_high - entry_low + 1, to, &retsize);
195
196 vecs_copy[entry_high].iov_len = old_iov_len - size;
197 vecs_copy[entry_high].iov_base += size;
198
199 entry_low = entry_high;
200
201 if (err)
202 break;
203
204 *retlen += retsize;
205 total_len -= wsize;
206
207 if (total_len == 0)
208 break;
209
210 err = -EINVAL;
211 to = 0;
212 }
213
214 kfree(vecs_copy);
215 return err;
216 }
217
218 static int
concat_read_oob(struct mtd_info * mtd,loff_t from,struct mtd_oob_ops * ops)219 concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
220 {
221 struct mtd_concat *concat = CONCAT(mtd);
222 struct mtd_oob_ops devops = *ops;
223 int i, err, ret = 0;
224
225 ops->retlen = ops->oobretlen = 0;
226
227 for (i = 0; i < concat->num_subdev; i++) {
228 struct mtd_info *subdev = concat->subdev[i];
229
230 if (from >= subdev->size) {
231 from -= subdev->size;
232 continue;
233 }
234
235 /* partial read ? */
236 if (from + devops.len > subdev->size)
237 devops.len = subdev->size - from;
238
239 err = mtd_read_oob(subdev, from, &devops);
240 ops->retlen += devops.retlen;
241 ops->oobretlen += devops.oobretlen;
242
243 /* Save information about bitflips! */
244 if (unlikely(err)) {
245 if (mtd_is_eccerr(err)) {
246 mtd->ecc_stats.failed++;
247 ret = err;
248 } else if (mtd_is_bitflip(err)) {
249 mtd->ecc_stats.corrected++;
250 /* Do not overwrite -EBADMSG !! */
251 if (!ret)
252 ret = err;
253 } else
254 return err;
255 }
256
257 if (devops.datbuf) {
258 devops.len = ops->len - ops->retlen;
259 if (!devops.len)
260 return ret;
261 devops.datbuf += devops.retlen;
262 }
263 if (devops.oobbuf) {
264 devops.ooblen = ops->ooblen - ops->oobretlen;
265 if (!devops.ooblen)
266 return ret;
267 devops.oobbuf += ops->oobretlen;
268 }
269
270 from = 0;
271 }
272 return -EINVAL;
273 }
274
275 static int
concat_write_oob(struct mtd_info * mtd,loff_t to,struct mtd_oob_ops * ops)276 concat_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops)
277 {
278 struct mtd_concat *concat = CONCAT(mtd);
279 struct mtd_oob_ops devops = *ops;
280 int i, err;
281
282 if (!(mtd->flags & MTD_WRITEABLE))
283 return -EROFS;
284
285 ops->retlen = ops->oobretlen = 0;
286
287 for (i = 0; i < concat->num_subdev; i++) {
288 struct mtd_info *subdev = concat->subdev[i];
289
290 if (to >= subdev->size) {
291 to -= subdev->size;
292 continue;
293 }
294
295 /* partial write ? */
296 if (to + devops.len > subdev->size)
297 devops.len = subdev->size - to;
298
299 err = mtd_write_oob(subdev, to, &devops);
300 ops->retlen += devops.retlen;
301 ops->oobretlen += devops.oobretlen;
302 if (err)
303 return err;
304
305 if (devops.datbuf) {
306 devops.len = ops->len - ops->retlen;
307 if (!devops.len)
308 return 0;
309 devops.datbuf += devops.retlen;
310 }
311 if (devops.oobbuf) {
312 devops.ooblen = ops->ooblen - ops->oobretlen;
313 if (!devops.ooblen)
314 return 0;
315 devops.oobbuf += devops.oobretlen;
316 }
317 to = 0;
318 }
319 return -EINVAL;
320 }
321
concat_erase(struct mtd_info * mtd,struct erase_info * instr)322 static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
323 {
324 struct mtd_concat *concat = CONCAT(mtd);
325 struct mtd_info *subdev;
326 int i, err;
327 uint64_t length, offset = 0;
328 struct erase_info *erase;
329
330 /*
331 * Check for proper erase block alignment of the to-be-erased area.
332 * It is easier to do this based on the super device's erase
333 * region info rather than looking at each particular sub-device
334 * in turn.
335 */
336 if (!concat->mtd.numeraseregions) {
337 /* the easy case: device has uniform erase block size */
338 if (instr->addr & (concat->mtd.erasesize - 1))
339 return -EINVAL;
340 if (instr->len & (concat->mtd.erasesize - 1))
341 return -EINVAL;
342 } else {
343 /* device has variable erase size */
344 struct mtd_erase_region_info *erase_regions =
345 concat->mtd.eraseregions;
346
347 /*
348 * Find the erase region where the to-be-erased area begins:
349 */
350 for (i = 0; i < concat->mtd.numeraseregions &&
351 instr->addr >= erase_regions[i].offset; i++) ;
352 --i;
353
354 /*
355 * Now erase_regions[i] is the region in which the
356 * to-be-erased area begins. Verify that the starting
357 * offset is aligned to this region's erase size:
358 */
359 if (i < 0 || instr->addr & (erase_regions[i].erasesize - 1))
360 return -EINVAL;
361
362 /*
363 * now find the erase region where the to-be-erased area ends:
364 */
365 for (; i < concat->mtd.numeraseregions &&
366 (instr->addr + instr->len) >= erase_regions[i].offset;
367 ++i) ;
368 --i;
369 /*
370 * check if the ending offset is aligned to this region's erase size
371 */
372 if (i < 0 || ((instr->addr + instr->len) &
373 (erase_regions[i].erasesize - 1)))
374 return -EINVAL;
375 }
376
377 /* make a local copy of instr to avoid modifying the caller's struct */
378 erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
379
380 if (!erase)
381 return -ENOMEM;
382
383 *erase = *instr;
384 length = instr->len;
385
386 /*
387 * find the subdevice where the to-be-erased area begins, adjust
388 * starting offset to be relative to the subdevice start
389 */
390 for (i = 0; i < concat->num_subdev; i++) {
391 subdev = concat->subdev[i];
392 if (subdev->size <= erase->addr) {
393 erase->addr -= subdev->size;
394 offset += subdev->size;
395 } else {
396 break;
397 }
398 }
399
400 /* must never happen since size limit has been verified above */
401 BUG_ON(i >= concat->num_subdev);
402
403 /* now do the erase: */
404 err = 0;
405 for (; length > 0; i++) {
406 /* loop for all subdevices affected by this request */
407 subdev = concat->subdev[i]; /* get current subdevice */
408
409 /* limit length to subdevice's size: */
410 if (erase->addr + length > subdev->size)
411 erase->len = subdev->size - erase->addr;
412 else
413 erase->len = length;
414
415 length -= erase->len;
416 if ((err = mtd_erase(subdev, erase))) {
417 /* sanity check: should never happen since
418 * block alignment has been checked above */
419 BUG_ON(err == -EINVAL);
420 if (erase->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
421 instr->fail_addr = erase->fail_addr + offset;
422 break;
423 }
424 /*
425 * erase->addr specifies the offset of the area to be
426 * erased *within the current subdevice*. It can be
427 * non-zero only the first time through this loop, i.e.
428 * for the first subdevice where blocks need to be erased.
429 * All the following erases must begin at the start of the
430 * current subdevice, i.e. at offset zero.
431 */
432 erase->addr = 0;
433 offset += subdev->size;
434 }
435 kfree(erase);
436
437 return err;
438 }
439
concat_xxlock(struct mtd_info * mtd,loff_t ofs,uint64_t len,bool is_lock)440 static int concat_xxlock(struct mtd_info *mtd, loff_t ofs, uint64_t len,
441 bool is_lock)
442 {
443 struct mtd_concat *concat = CONCAT(mtd);
444 int i, err = -EINVAL;
445
446 for (i = 0; i < concat->num_subdev; i++) {
447 struct mtd_info *subdev = concat->subdev[i];
448 uint64_t size;
449
450 if (ofs >= subdev->size) {
451 size = 0;
452 ofs -= subdev->size;
453 continue;
454 }
455 if (ofs + len > subdev->size)
456 size = subdev->size - ofs;
457 else
458 size = len;
459
460 if (is_lock)
461 err = mtd_lock(subdev, ofs, size);
462 else
463 err = mtd_unlock(subdev, ofs, size);
464 if (err)
465 break;
466
467 len -= size;
468 if (len == 0)
469 break;
470
471 err = -EINVAL;
472 ofs = 0;
473 }
474
475 return err;
476 }
477
concat_lock(struct mtd_info * mtd,loff_t ofs,uint64_t len)478 static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
479 {
480 return concat_xxlock(mtd, ofs, len, true);
481 }
482
concat_unlock(struct mtd_info * mtd,loff_t ofs,uint64_t len)483 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
484 {
485 return concat_xxlock(mtd, ofs, len, false);
486 }
487
concat_is_locked(struct mtd_info * mtd,loff_t ofs,uint64_t len)488 static int concat_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
489 {
490 struct mtd_concat *concat = CONCAT(mtd);
491 int i, err = -EINVAL;
492
493 for (i = 0; i < concat->num_subdev; i++) {
494 struct mtd_info *subdev = concat->subdev[i];
495
496 if (ofs >= subdev->size) {
497 ofs -= subdev->size;
498 continue;
499 }
500
501 if (ofs + len > subdev->size)
502 break;
503
504 return mtd_is_locked(subdev, ofs, len);
505 }
506
507 return err;
508 }
509
concat_sync(struct mtd_info * mtd)510 static void concat_sync(struct mtd_info *mtd)
511 {
512 struct mtd_concat *concat = CONCAT(mtd);
513 int i;
514
515 for (i = 0; i < concat->num_subdev; i++) {
516 struct mtd_info *subdev = concat->subdev[i];
517 mtd_sync(subdev);
518 }
519 }
520
concat_suspend(struct mtd_info * mtd)521 static int concat_suspend(struct mtd_info *mtd)
522 {
523 struct mtd_concat *concat = CONCAT(mtd);
524 int i, rc = 0;
525
526 for (i = 0; i < concat->num_subdev; i++) {
527 struct mtd_info *subdev = concat->subdev[i];
528 if ((rc = mtd_suspend(subdev)) < 0)
529 return rc;
530 }
531 return rc;
532 }
533
concat_resume(struct mtd_info * mtd)534 static void concat_resume(struct mtd_info *mtd)
535 {
536 struct mtd_concat *concat = CONCAT(mtd);
537 int i;
538
539 for (i = 0; i < concat->num_subdev; i++) {
540 struct mtd_info *subdev = concat->subdev[i];
541 mtd_resume(subdev);
542 }
543 }
544
concat_block_isbad(struct mtd_info * mtd,loff_t ofs)545 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
546 {
547 struct mtd_concat *concat = CONCAT(mtd);
548 int i, res = 0;
549
550 if (!mtd_can_have_bb(concat->subdev[0]))
551 return res;
552
553 for (i = 0; i < concat->num_subdev; i++) {
554 struct mtd_info *subdev = concat->subdev[i];
555
556 if (ofs >= subdev->size) {
557 ofs -= subdev->size;
558 continue;
559 }
560
561 res = mtd_block_isbad(subdev, ofs);
562 break;
563 }
564
565 return res;
566 }
567
concat_block_markbad(struct mtd_info * mtd,loff_t ofs)568 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
569 {
570 struct mtd_concat *concat = CONCAT(mtd);
571 int i, err = -EINVAL;
572
573 for (i = 0; i < concat->num_subdev; i++) {
574 struct mtd_info *subdev = concat->subdev[i];
575
576 if (ofs >= subdev->size) {
577 ofs -= subdev->size;
578 continue;
579 }
580
581 err = mtd_block_markbad(subdev, ofs);
582 if (!err)
583 mtd->ecc_stats.badblocks++;
584 break;
585 }
586
587 return err;
588 }
589
590 /*
591 * This function constructs a virtual MTD device by concatenating
592 * num_devs MTD devices. A pointer to the new device object is
593 * stored to *new_dev upon success. This function does _not_
594 * register any devices: this is the caller's responsibility.
595 */
mtd_concat_create(struct mtd_info * subdev[],int num_devs,const char * name)596 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[], /* subdevices to concatenate */
597 int num_devs, /* number of subdevices */
598 const char *name)
599 { /* name for the new device */
600 int i;
601 size_t size;
602 struct mtd_concat *concat;
603 uint32_t max_erasesize, curr_erasesize;
604 int num_erase_region;
605 int max_writebufsize = 0;
606
607 printk(KERN_NOTICE "Concatenating MTD devices:\n");
608 for (i = 0; i < num_devs; i++)
609 printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
610 printk(KERN_NOTICE "into device \"%s\"\n", name);
611
612 /* allocate the device structure */
613 size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
614 concat = kzalloc(size, GFP_KERNEL);
615 if (!concat) {
616 printk
617 ("memory allocation error while creating concatenated device \"%s\"\n",
618 name);
619 return NULL;
620 }
621 concat->subdev = (struct mtd_info **) (concat + 1);
622
623 /*
624 * Set up the new "super" device's MTD object structure, check for
625 * incompatibilities between the subdevices.
626 */
627 concat->mtd.type = subdev[0]->type;
628 concat->mtd.flags = subdev[0]->flags;
629 concat->mtd.size = subdev[0]->size;
630 concat->mtd.erasesize = subdev[0]->erasesize;
631 concat->mtd.writesize = subdev[0]->writesize;
632
633 for (i = 0; i < num_devs; i++)
634 if (max_writebufsize < subdev[i]->writebufsize)
635 max_writebufsize = subdev[i]->writebufsize;
636 concat->mtd.writebufsize = max_writebufsize;
637
638 concat->mtd.subpage_sft = subdev[0]->subpage_sft;
639 concat->mtd.oobsize = subdev[0]->oobsize;
640 concat->mtd.oobavail = subdev[0]->oobavail;
641 if (subdev[0]->_writev)
642 concat->mtd._writev = concat_writev;
643 if (subdev[0]->_read_oob)
644 concat->mtd._read_oob = concat_read_oob;
645 if (subdev[0]->_write_oob)
646 concat->mtd._write_oob = concat_write_oob;
647 if (subdev[0]->_block_isbad)
648 concat->mtd._block_isbad = concat_block_isbad;
649 if (subdev[0]->_block_markbad)
650 concat->mtd._block_markbad = concat_block_markbad;
651
652 concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
653
654 concat->subdev[0] = subdev[0];
655
656 for (i = 1; i < num_devs; i++) {
657 if (concat->mtd.type != subdev[i]->type) {
658 kfree(concat);
659 printk("Incompatible device type on \"%s\"\n",
660 subdev[i]->name);
661 return NULL;
662 }
663 if (concat->mtd.flags != subdev[i]->flags) {
664 /*
665 * Expect all flags except MTD_WRITEABLE to be
666 * equal on all subdevices.
667 */
668 if ((concat->mtd.flags ^ subdev[i]->
669 flags) & ~MTD_WRITEABLE) {
670 kfree(concat);
671 printk("Incompatible device flags on \"%s\"\n",
672 subdev[i]->name);
673 return NULL;
674 } else
675 /* if writeable attribute differs,
676 make super device writeable */
677 concat->mtd.flags |=
678 subdev[i]->flags & MTD_WRITEABLE;
679 }
680
681 concat->mtd.size += subdev[i]->size;
682 concat->mtd.ecc_stats.badblocks +=
683 subdev[i]->ecc_stats.badblocks;
684 if (concat->mtd.writesize != subdev[i]->writesize ||
685 concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
686 concat->mtd.oobsize != subdev[i]->oobsize ||
687 !concat->mtd._read_oob != !subdev[i]->_read_oob ||
688 !concat->mtd._write_oob != !subdev[i]->_write_oob) {
689 kfree(concat);
690 printk("Incompatible OOB or ECC data on \"%s\"\n",
691 subdev[i]->name);
692 return NULL;
693 }
694 concat->subdev[i] = subdev[i];
695
696 }
697
698 mtd_set_ooblayout(&concat->mtd, subdev[0]->ooblayout);
699
700 concat->num_subdev = num_devs;
701 concat->mtd.name = name;
702
703 concat->mtd._erase = concat_erase;
704 concat->mtd._read = concat_read;
705 concat->mtd._write = concat_write;
706 concat->mtd._sync = concat_sync;
707 concat->mtd._lock = concat_lock;
708 concat->mtd._unlock = concat_unlock;
709 concat->mtd._is_locked = concat_is_locked;
710 concat->mtd._suspend = concat_suspend;
711 concat->mtd._resume = concat_resume;
712
713 /*
714 * Combine the erase block size info of the subdevices:
715 *
716 * first, walk the map of the new device and see how
717 * many changes in erase size we have
718 */
719 max_erasesize = curr_erasesize = subdev[0]->erasesize;
720 num_erase_region = 1;
721 for (i = 0; i < num_devs; i++) {
722 if (subdev[i]->numeraseregions == 0) {
723 /* current subdevice has uniform erase size */
724 if (subdev[i]->erasesize != curr_erasesize) {
725 /* if it differs from the last subdevice's erase size, count it */
726 ++num_erase_region;
727 curr_erasesize = subdev[i]->erasesize;
728 if (curr_erasesize > max_erasesize)
729 max_erasesize = curr_erasesize;
730 }
731 } else {
732 /* current subdevice has variable erase size */
733 int j;
734 for (j = 0; j < subdev[i]->numeraseregions; j++) {
735
736 /* walk the list of erase regions, count any changes */
737 if (subdev[i]->eraseregions[j].erasesize !=
738 curr_erasesize) {
739 ++num_erase_region;
740 curr_erasesize =
741 subdev[i]->eraseregions[j].
742 erasesize;
743 if (curr_erasesize > max_erasesize)
744 max_erasesize = curr_erasesize;
745 }
746 }
747 }
748 }
749
750 if (num_erase_region == 1) {
751 /*
752 * All subdevices have the same uniform erase size.
753 * This is easy:
754 */
755 concat->mtd.erasesize = curr_erasesize;
756 concat->mtd.numeraseregions = 0;
757 } else {
758 uint64_t tmp64;
759
760 /*
761 * erase block size varies across the subdevices: allocate
762 * space to store the data describing the variable erase regions
763 */
764 struct mtd_erase_region_info *erase_region_p;
765 uint64_t begin, position;
766
767 concat->mtd.erasesize = max_erasesize;
768 concat->mtd.numeraseregions = num_erase_region;
769 concat->mtd.eraseregions = erase_region_p =
770 kmalloc_array(num_erase_region,
771 sizeof(struct mtd_erase_region_info),
772 GFP_KERNEL);
773 if (!erase_region_p) {
774 kfree(concat);
775 printk
776 ("memory allocation error while creating erase region list"
777 " for device \"%s\"\n", name);
778 return NULL;
779 }
780
781 /*
782 * walk the map of the new device once more and fill in
783 * in erase region info:
784 */
785 curr_erasesize = subdev[0]->erasesize;
786 begin = position = 0;
787 for (i = 0; i < num_devs; i++) {
788 if (subdev[i]->numeraseregions == 0) {
789 /* current subdevice has uniform erase size */
790 if (subdev[i]->erasesize != curr_erasesize) {
791 /*
792 * fill in an mtd_erase_region_info structure for the area
793 * we have walked so far:
794 */
795 erase_region_p->offset = begin;
796 erase_region_p->erasesize =
797 curr_erasesize;
798 tmp64 = position - begin;
799 do_div(tmp64, curr_erasesize);
800 erase_region_p->numblocks = tmp64;
801 begin = position;
802
803 curr_erasesize = subdev[i]->erasesize;
804 ++erase_region_p;
805 }
806 position += subdev[i]->size;
807 } else {
808 /* current subdevice has variable erase size */
809 int j;
810 for (j = 0; j < subdev[i]->numeraseregions; j++) {
811 /* walk the list of erase regions, count any changes */
812 if (subdev[i]->eraseregions[j].
813 erasesize != curr_erasesize) {
814 erase_region_p->offset = begin;
815 erase_region_p->erasesize =
816 curr_erasesize;
817 tmp64 = position - begin;
818 do_div(tmp64, curr_erasesize);
819 erase_region_p->numblocks = tmp64;
820 begin = position;
821
822 curr_erasesize =
823 subdev[i]->eraseregions[j].
824 erasesize;
825 ++erase_region_p;
826 }
827 position +=
828 subdev[i]->eraseregions[j].
829 numblocks * (uint64_t)curr_erasesize;
830 }
831 }
832 }
833 /* Now write the final entry */
834 erase_region_p->offset = begin;
835 erase_region_p->erasesize = curr_erasesize;
836 tmp64 = position - begin;
837 do_div(tmp64, curr_erasesize);
838 erase_region_p->numblocks = tmp64;
839 }
840
841 return &concat->mtd;
842 }
843
844 /*
845 * This function destroys an MTD object obtained from concat_mtd_devs()
846 */
847
mtd_concat_destroy(struct mtd_info * mtd)848 void mtd_concat_destroy(struct mtd_info *mtd)
849 {
850 struct mtd_concat *concat = CONCAT(mtd);
851 if (concat->mtd.numeraseregions)
852 kfree(concat->mtd.eraseregions);
853 kfree(concat);
854 }
855
856 EXPORT_SYMBOL(mtd_concat_create);
857 EXPORT_SYMBOL(mtd_concat_destroy);
858
859 MODULE_LICENSE("GPL");
860 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
861 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");
862