ia64/linux-2.6.18-xen.hg

view drivers/mtd/mtdconcat.c @ 893:f994bfe9b93b

linux/blktap2: reduce TLB flush scope

c/s 885 added very coarse TLB flushing. Since these flushes always
follow single page updates, single page flushes (when available) are
sufficient.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Jun 04 10:32:57 2009 +0100 (2009-06-04)
parents 831230e53067
children
line source
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 */
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>
19 #include <linux/mtd/mtd.h>
20 #include <linux/mtd/concat.h>
22 #include <asm/div64.h>
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 };
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 *)))
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))
49 /*
50 * MTD methods which look up the relevant subdevice, translate the
51 * effective address and pass through to the subdevice.
52 */
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 ret = 0, err;
60 int i;
62 *retlen = 0;
64 for (i = 0; i < concat->num_subdev; i++) {
65 struct mtd_info *subdev = concat->subdev[i];
66 size_t size, retsize;
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;
81 err = subdev->read(subdev, from, size, &retsize, buf);
83 /* Save information about bitflips! */
84 if (unlikely(err)) {
85 if (err == -EBADMSG) {
86 mtd->ecc_stats.failed++;
87 ret = err;
88 } else if (err == -EUCLEAN) {
89 mtd->ecc_stats.corrected++;
90 /* Do not overwrite -EBADMSG !! */
91 if (!ret)
92 ret = err;
93 } else
94 return err;
95 }
97 *retlen += retsize;
98 len -= size;
99 if (len == 0)
100 return ret;
102 buf += size;
103 from = 0;
104 }
105 return -EINVAL;
106 }
108 static int
109 concat_write(struct mtd_info *mtd, loff_t to, size_t len,
110 size_t * retlen, const u_char * buf)
111 {
112 struct mtd_concat *concat = CONCAT(mtd);
113 int err = -EINVAL;
114 int i;
116 if (!(mtd->flags & MTD_WRITEABLE))
117 return -EROFS;
119 *retlen = 0;
121 for (i = 0; i < concat->num_subdev; i++) {
122 struct mtd_info *subdev = concat->subdev[i];
123 size_t size, retsize;
125 if (to >= subdev->size) {
126 size = 0;
127 to -= subdev->size;
128 continue;
129 }
130 if (to + len > subdev->size)
131 size = subdev->size - to;
132 else
133 size = len;
135 if (!(subdev->flags & MTD_WRITEABLE))
136 err = -EROFS;
137 else
138 err = subdev->write(subdev, to, size, &retsize, buf);
140 if (err)
141 break;
143 *retlen += retsize;
144 len -= size;
145 if (len == 0)
146 break;
148 err = -EINVAL;
149 buf += size;
150 to = 0;
151 }
152 return err;
153 }
155 static int
156 concat_writev(struct mtd_info *mtd, const struct kvec *vecs,
157 unsigned long count, loff_t to, size_t * retlen)
158 {
159 struct mtd_concat *concat = CONCAT(mtd);
160 struct kvec *vecs_copy;
161 unsigned long entry_low, entry_high;
162 size_t total_len = 0;
163 int i;
164 int err = -EINVAL;
166 if (!(mtd->flags & MTD_WRITEABLE))
167 return -EROFS;
169 *retlen = 0;
171 /* Calculate total length of data */
172 for (i = 0; i < count; i++)
173 total_len += vecs[i].iov_len;
175 /* Do not allow write past end of device */
176 if ((to + total_len) > mtd->size)
177 return -EINVAL;
179 /* Check alignment */
180 if (mtd->writesize > 1) {
181 loff_t __to = to;
182 if (do_div(__to, mtd->writesize) || (total_len % mtd->writesize))
183 return -EINVAL;
184 }
186 /* make a copy of vecs */
187 vecs_copy = kmalloc(sizeof(struct kvec) * count, GFP_KERNEL);
188 if (!vecs_copy)
189 return -ENOMEM;
190 memcpy(vecs_copy, vecs, sizeof(struct kvec) * count);
192 entry_low = 0;
193 for (i = 0; i < concat->num_subdev; i++) {
194 struct mtd_info *subdev = concat->subdev[i];
195 size_t size, wsize, retsize, old_iov_len;
197 if (to >= subdev->size) {
198 to -= subdev->size;
199 continue;
200 }
202 size = min(total_len, (size_t)(subdev->size - to));
203 wsize = size; /* store for future use */
205 entry_high = entry_low;
206 while (entry_high < count) {
207 if (size <= vecs_copy[entry_high].iov_len)
208 break;
209 size -= vecs_copy[entry_high++].iov_len;
210 }
212 old_iov_len = vecs_copy[entry_high].iov_len;
213 vecs_copy[entry_high].iov_len = size;
215 if (!(subdev->flags & MTD_WRITEABLE))
216 err = -EROFS;
217 else
218 err = subdev->writev(subdev, &vecs_copy[entry_low],
219 entry_high - entry_low + 1, to, &retsize);
221 vecs_copy[entry_high].iov_len = old_iov_len - size;
222 vecs_copy[entry_high].iov_base += size;
224 entry_low = entry_high;
226 if (err)
227 break;
229 *retlen += retsize;
230 total_len -= wsize;
232 if (total_len == 0)
233 break;
235 err = -EINVAL;
236 to = 0;
237 }
239 kfree(vecs_copy);
240 return err;
241 }
243 static int
244 concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
245 {
246 struct mtd_concat *concat = CONCAT(mtd);
247 struct mtd_oob_ops devops = *ops;
248 int i, err, ret = 0;
250 ops->retlen = 0;
252 for (i = 0; i < concat->num_subdev; i++) {
253 struct mtd_info *subdev = concat->subdev[i];
255 if (from >= subdev->size) {
256 from -= subdev->size;
257 continue;
258 }
260 /* partial read ? */
261 if (from + devops.len > subdev->size)
262 devops.len = subdev->size - from;
264 err = subdev->read_oob(subdev, from, &devops);
265 ops->retlen += devops.retlen;
267 /* Save information about bitflips! */
268 if (unlikely(err)) {
269 if (err == -EBADMSG) {
270 mtd->ecc_stats.failed++;
271 ret = err;
272 } else if (err == -EUCLEAN) {
273 mtd->ecc_stats.corrected++;
274 /* Do not overwrite -EBADMSG !! */
275 if (!ret)
276 ret = err;
277 } else
278 return err;
279 }
281 devops.len = ops->len - ops->retlen;
282 if (!devops.len)
283 return ret;
285 if (devops.datbuf)
286 devops.datbuf += devops.retlen;
287 if (devops.oobbuf)
288 devops.oobbuf += devops.ooblen;
290 from = 0;
291 }
292 return -EINVAL;
293 }
295 static int
296 concat_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops)
297 {
298 struct mtd_concat *concat = CONCAT(mtd);
299 struct mtd_oob_ops devops = *ops;
300 int i, err;
302 if (!(mtd->flags & MTD_WRITEABLE))
303 return -EROFS;
305 ops->retlen = 0;
307 for (i = 0; i < concat->num_subdev; i++) {
308 struct mtd_info *subdev = concat->subdev[i];
310 if (to >= subdev->size) {
311 to -= subdev->size;
312 continue;
313 }
315 /* partial write ? */
316 if (to + devops.len > subdev->size)
317 devops.len = subdev->size - to;
319 err = subdev->write_oob(subdev, to, &devops);
320 ops->retlen += devops.retlen;
321 if (err)
322 return err;
324 devops.len = ops->len - ops->retlen;
325 if (!devops.len)
326 return 0;
328 if (devops.datbuf)
329 devops.datbuf += devops.retlen;
330 if (devops.oobbuf)
331 devops.oobbuf += devops.ooblen;
332 to = 0;
333 }
334 return -EINVAL;
335 }
337 static void concat_erase_callback(struct erase_info *instr)
338 {
339 wake_up((wait_queue_head_t *) instr->priv);
340 }
342 static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase)
343 {
344 int err;
345 wait_queue_head_t waitq;
346 DECLARE_WAITQUEUE(wait, current);
348 /*
349 * This code was stol^H^H^H^Hinspired by mtdchar.c
350 */
351 init_waitqueue_head(&waitq);
353 erase->mtd = mtd;
354 erase->callback = concat_erase_callback;
355 erase->priv = (unsigned long) &waitq;
357 /*
358 * FIXME: Allow INTERRUPTIBLE. Which means
359 * not having the wait_queue head on the stack.
360 */
361 err = mtd->erase(mtd, erase);
362 if (!err) {
363 set_current_state(TASK_UNINTERRUPTIBLE);
364 add_wait_queue(&waitq, &wait);
365 if (erase->state != MTD_ERASE_DONE
366 && erase->state != MTD_ERASE_FAILED)
367 schedule();
368 remove_wait_queue(&waitq, &wait);
369 set_current_state(TASK_RUNNING);
371 err = (erase->state == MTD_ERASE_FAILED) ? -EIO : 0;
372 }
373 return err;
374 }
376 static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
377 {
378 struct mtd_concat *concat = CONCAT(mtd);
379 struct mtd_info *subdev;
380 int i, err;
381 u_int32_t length, offset = 0;
382 struct erase_info *erase;
384 if (!(mtd->flags & MTD_WRITEABLE))
385 return -EROFS;
387 if (instr->addr > concat->mtd.size)
388 return -EINVAL;
390 if (instr->len + instr->addr > concat->mtd.size)
391 return -EINVAL;
393 /*
394 * Check for proper erase block alignment of the to-be-erased area.
395 * It is easier to do this based on the super device's erase
396 * region info rather than looking at each particular sub-device
397 * in turn.
398 */
399 if (!concat->mtd.numeraseregions) {
400 /* the easy case: device has uniform erase block size */
401 if (instr->addr & (concat->mtd.erasesize - 1))
402 return -EINVAL;
403 if (instr->len & (concat->mtd.erasesize - 1))
404 return -EINVAL;
405 } else {
406 /* device has variable erase size */
407 struct mtd_erase_region_info *erase_regions =
408 concat->mtd.eraseregions;
410 /*
411 * Find the erase region where the to-be-erased area begins:
412 */
413 for (i = 0; i < concat->mtd.numeraseregions &&
414 instr->addr >= erase_regions[i].offset; i++) ;
415 --i;
417 /*
418 * Now erase_regions[i] is the region in which the
419 * to-be-erased area begins. Verify that the starting
420 * offset is aligned to this region's erase size:
421 */
422 if (instr->addr & (erase_regions[i].erasesize - 1))
423 return -EINVAL;
425 /*
426 * now find the erase region where the to-be-erased area ends:
427 */
428 for (; i < concat->mtd.numeraseregions &&
429 (instr->addr + instr->len) >= erase_regions[i].offset;
430 ++i) ;
431 --i;
432 /*
433 * check if the ending offset is aligned to this region's erase size
434 */
435 if ((instr->addr + instr->len) & (erase_regions[i].erasesize -
436 1))
437 return -EINVAL;
438 }
440 instr->fail_addr = 0xffffffff;
442 /* make a local copy of instr to avoid modifying the caller's struct */
443 erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
445 if (!erase)
446 return -ENOMEM;
448 *erase = *instr;
449 length = instr->len;
451 /*
452 * find the subdevice where the to-be-erased area begins, adjust
453 * starting offset to be relative to the subdevice start
454 */
455 for (i = 0; i < concat->num_subdev; i++) {
456 subdev = concat->subdev[i];
457 if (subdev->size <= erase->addr) {
458 erase->addr -= subdev->size;
459 offset += subdev->size;
460 } else {
461 break;
462 }
463 }
465 /* must never happen since size limit has been verified above */
466 BUG_ON(i >= concat->num_subdev);
468 /* now do the erase: */
469 err = 0;
470 for (; length > 0; i++) {
471 /* loop for all subdevices affected by this request */
472 subdev = concat->subdev[i]; /* get current subdevice */
474 /* limit length to subdevice's size: */
475 if (erase->addr + length > subdev->size)
476 erase->len = subdev->size - erase->addr;
477 else
478 erase->len = length;
480 if (!(subdev->flags & MTD_WRITEABLE)) {
481 err = -EROFS;
482 break;
483 }
484 length -= erase->len;
485 if ((err = concat_dev_erase(subdev, erase))) {
486 /* sanity check: should never happen since
487 * block alignment has been checked above */
488 BUG_ON(err == -EINVAL);
489 if (erase->fail_addr != 0xffffffff)
490 instr->fail_addr = erase->fail_addr + offset;
491 break;
492 }
493 /*
494 * erase->addr specifies the offset of the area to be
495 * erased *within the current subdevice*. It can be
496 * non-zero only the first time through this loop, i.e.
497 * for the first subdevice where blocks need to be erased.
498 * All the following erases must begin at the start of the
499 * current subdevice, i.e. at offset zero.
500 */
501 erase->addr = 0;
502 offset += subdev->size;
503 }
504 instr->state = erase->state;
505 kfree(erase);
506 if (err)
507 return err;
509 if (instr->callback)
510 instr->callback(instr);
511 return 0;
512 }
514 static int concat_lock(struct mtd_info *mtd, loff_t ofs, size_t len)
515 {
516 struct mtd_concat *concat = CONCAT(mtd);
517 int i, err = -EINVAL;
519 if ((len + ofs) > mtd->size)
520 return -EINVAL;
522 for (i = 0; i < concat->num_subdev; i++) {
523 struct mtd_info *subdev = concat->subdev[i];
524 size_t size;
526 if (ofs >= subdev->size) {
527 size = 0;
528 ofs -= subdev->size;
529 continue;
530 }
531 if (ofs + len > subdev->size)
532 size = subdev->size - ofs;
533 else
534 size = len;
536 err = subdev->lock(subdev, ofs, size);
538 if (err)
539 break;
541 len -= size;
542 if (len == 0)
543 break;
545 err = -EINVAL;
546 ofs = 0;
547 }
549 return err;
550 }
552 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, size_t len)
553 {
554 struct mtd_concat *concat = CONCAT(mtd);
555 int i, err = 0;
557 if ((len + ofs) > mtd->size)
558 return -EINVAL;
560 for (i = 0; i < concat->num_subdev; i++) {
561 struct mtd_info *subdev = concat->subdev[i];
562 size_t size;
564 if (ofs >= subdev->size) {
565 size = 0;
566 ofs -= subdev->size;
567 continue;
568 }
569 if (ofs + len > subdev->size)
570 size = subdev->size - ofs;
571 else
572 size = len;
574 err = subdev->unlock(subdev, ofs, size);
576 if (err)
577 break;
579 len -= size;
580 if (len == 0)
581 break;
583 err = -EINVAL;
584 ofs = 0;
585 }
587 return err;
588 }
590 static void concat_sync(struct mtd_info *mtd)
591 {
592 struct mtd_concat *concat = CONCAT(mtd);
593 int i;
595 for (i = 0; i < concat->num_subdev; i++) {
596 struct mtd_info *subdev = concat->subdev[i];
597 subdev->sync(subdev);
598 }
599 }
601 static int concat_suspend(struct mtd_info *mtd)
602 {
603 struct mtd_concat *concat = CONCAT(mtd);
604 int i, rc = 0;
606 for (i = 0; i < concat->num_subdev; i++) {
607 struct mtd_info *subdev = concat->subdev[i];
608 if ((rc = subdev->suspend(subdev)) < 0)
609 return rc;
610 }
611 return rc;
612 }
614 static void concat_resume(struct mtd_info *mtd)
615 {
616 struct mtd_concat *concat = CONCAT(mtd);
617 int i;
619 for (i = 0; i < concat->num_subdev; i++) {
620 struct mtd_info *subdev = concat->subdev[i];
621 subdev->resume(subdev);
622 }
623 }
625 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
626 {
627 struct mtd_concat *concat = CONCAT(mtd);
628 int i, res = 0;
630 if (!concat->subdev[0]->block_isbad)
631 return res;
633 if (ofs > mtd->size)
634 return -EINVAL;
636 for (i = 0; i < concat->num_subdev; i++) {
637 struct mtd_info *subdev = concat->subdev[i];
639 if (ofs >= subdev->size) {
640 ofs -= subdev->size;
641 continue;
642 }
644 res = subdev->block_isbad(subdev, ofs);
645 break;
646 }
648 return res;
649 }
651 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
652 {
653 struct mtd_concat *concat = CONCAT(mtd);
654 int i, err = -EINVAL;
656 if (!concat->subdev[0]->block_markbad)
657 return 0;
659 if (ofs > mtd->size)
660 return -EINVAL;
662 for (i = 0; i < concat->num_subdev; i++) {
663 struct mtd_info *subdev = concat->subdev[i];
665 if (ofs >= subdev->size) {
666 ofs -= subdev->size;
667 continue;
668 }
670 err = subdev->block_markbad(subdev, ofs);
671 if (!err)
672 mtd->ecc_stats.badblocks++;
673 break;
674 }
676 return err;
677 }
679 /*
680 * This function constructs a virtual MTD device by concatenating
681 * num_devs MTD devices. A pointer to the new device object is
682 * stored to *new_dev upon success. This function does _not_
683 * register any devices: this is the caller's responsibility.
684 */
685 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[], /* subdevices to concatenate */
686 int num_devs, /* number of subdevices */
687 char *name)
688 { /* name for the new device */
689 int i;
690 size_t size;
691 struct mtd_concat *concat;
692 u_int32_t max_erasesize, curr_erasesize;
693 int num_erase_region;
695 printk(KERN_NOTICE "Concatenating MTD devices:\n");
696 for (i = 0; i < num_devs; i++)
697 printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
698 printk(KERN_NOTICE "into device \"%s\"\n", name);
700 /* allocate the device structure */
701 size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
702 concat = kmalloc(size, GFP_KERNEL);
703 if (!concat) {
704 printk
705 ("memory allocation error while creating concatenated device \"%s\"\n",
706 name);
707 return NULL;
708 }
709 memset(concat, 0, size);
710 concat->subdev = (struct mtd_info **) (concat + 1);
712 /*
713 * Set up the new "super" device's MTD object structure, check for
714 * incompatibilites between the subdevices.
715 */
716 concat->mtd.type = subdev[0]->type;
717 concat->mtd.flags = subdev[0]->flags;
718 concat->mtd.size = subdev[0]->size;
719 concat->mtd.erasesize = subdev[0]->erasesize;
720 concat->mtd.writesize = subdev[0]->writesize;
721 concat->mtd.oobsize = subdev[0]->oobsize;
722 concat->mtd.ecctype = subdev[0]->ecctype;
723 concat->mtd.eccsize = subdev[0]->eccsize;
724 if (subdev[0]->writev)
725 concat->mtd.writev = concat_writev;
726 if (subdev[0]->read_oob)
727 concat->mtd.read_oob = concat_read_oob;
728 if (subdev[0]->write_oob)
729 concat->mtd.write_oob = concat_write_oob;
730 if (subdev[0]->block_isbad)
731 concat->mtd.block_isbad = concat_block_isbad;
732 if (subdev[0]->block_markbad)
733 concat->mtd.block_markbad = concat_block_markbad;
735 concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
737 concat->subdev[0] = subdev[0];
739 for (i = 1; i < num_devs; i++) {
740 if (concat->mtd.type != subdev[i]->type) {
741 kfree(concat);
742 printk("Incompatible device type on \"%s\"\n",
743 subdev[i]->name);
744 return NULL;
745 }
746 if (concat->mtd.flags != subdev[i]->flags) {
747 /*
748 * Expect all flags except MTD_WRITEABLE to be
749 * equal on all subdevices.
750 */
751 if ((concat->mtd.flags ^ subdev[i]->
752 flags) & ~MTD_WRITEABLE) {
753 kfree(concat);
754 printk("Incompatible device flags on \"%s\"\n",
755 subdev[i]->name);
756 return NULL;
757 } else
758 /* if writeable attribute differs,
759 make super device writeable */
760 concat->mtd.flags |=
761 subdev[i]->flags & MTD_WRITEABLE;
762 }
763 concat->mtd.size += subdev[i]->size;
764 concat->mtd.ecc_stats.badblocks +=
765 subdev[i]->ecc_stats.badblocks;
766 if (concat->mtd.writesize != subdev[i]->writesize ||
767 concat->mtd.oobsize != subdev[i]->oobsize ||
768 concat->mtd.ecctype != subdev[i]->ecctype ||
769 concat->mtd.eccsize != subdev[i]->eccsize ||
770 !concat->mtd.read_oob != !subdev[i]->read_oob ||
771 !concat->mtd.write_oob != !subdev[i]->write_oob) {
772 kfree(concat);
773 printk("Incompatible OOB or ECC data on \"%s\"\n",
774 subdev[i]->name);
775 return NULL;
776 }
777 concat->subdev[i] = subdev[i];
779 }
781 concat->mtd.ecclayout = subdev[0]->ecclayout;
783 concat->num_subdev = num_devs;
784 concat->mtd.name = name;
786 concat->mtd.erase = concat_erase;
787 concat->mtd.read = concat_read;
788 concat->mtd.write = concat_write;
789 concat->mtd.sync = concat_sync;
790 concat->mtd.lock = concat_lock;
791 concat->mtd.unlock = concat_unlock;
792 concat->mtd.suspend = concat_suspend;
793 concat->mtd.resume = concat_resume;
795 /*
796 * Combine the erase block size info of the subdevices:
797 *
798 * first, walk the map of the new device and see how
799 * many changes in erase size we have
800 */
801 max_erasesize = curr_erasesize = subdev[0]->erasesize;
802 num_erase_region = 1;
803 for (i = 0; i < num_devs; i++) {
804 if (subdev[i]->numeraseregions == 0) {
805 /* current subdevice has uniform erase size */
806 if (subdev[i]->erasesize != curr_erasesize) {
807 /* if it differs from the last subdevice's erase size, count it */
808 ++num_erase_region;
809 curr_erasesize = subdev[i]->erasesize;
810 if (curr_erasesize > max_erasesize)
811 max_erasesize = curr_erasesize;
812 }
813 } else {
814 /* current subdevice has variable erase size */
815 int j;
816 for (j = 0; j < subdev[i]->numeraseregions; j++) {
818 /* walk the list of erase regions, count any changes */
819 if (subdev[i]->eraseregions[j].erasesize !=
820 curr_erasesize) {
821 ++num_erase_region;
822 curr_erasesize =
823 subdev[i]->eraseregions[j].
824 erasesize;
825 if (curr_erasesize > max_erasesize)
826 max_erasesize = curr_erasesize;
827 }
828 }
829 }
830 }
832 if (num_erase_region == 1) {
833 /*
834 * All subdevices have the same uniform erase size.
835 * This is easy:
836 */
837 concat->mtd.erasesize = curr_erasesize;
838 concat->mtd.numeraseregions = 0;
839 } else {
840 /*
841 * erase block size varies across the subdevices: allocate
842 * space to store the data describing the variable erase regions
843 */
844 struct mtd_erase_region_info *erase_region_p;
845 u_int32_t begin, position;
847 concat->mtd.erasesize = max_erasesize;
848 concat->mtd.numeraseregions = num_erase_region;
849 concat->mtd.eraseregions = erase_region_p =
850 kmalloc(num_erase_region *
851 sizeof (struct mtd_erase_region_info), GFP_KERNEL);
852 if (!erase_region_p) {
853 kfree(concat);
854 printk
855 ("memory allocation error while creating erase region list"
856 " for device \"%s\"\n", name);
857 return NULL;
858 }
860 /*
861 * walk the map of the new device once more and fill in
862 * in erase region info:
863 */
864 curr_erasesize = subdev[0]->erasesize;
865 begin = position = 0;
866 for (i = 0; i < num_devs; i++) {
867 if (subdev[i]->numeraseregions == 0) {
868 /* current subdevice has uniform erase size */
869 if (subdev[i]->erasesize != curr_erasesize) {
870 /*
871 * fill in an mtd_erase_region_info structure for the area
872 * we have walked so far:
873 */
874 erase_region_p->offset = begin;
875 erase_region_p->erasesize =
876 curr_erasesize;
877 erase_region_p->numblocks =
878 (position - begin) / curr_erasesize;
879 begin = position;
881 curr_erasesize = subdev[i]->erasesize;
882 ++erase_region_p;
883 }
884 position += subdev[i]->size;
885 } else {
886 /* current subdevice has variable erase size */
887 int j;
888 for (j = 0; j < subdev[i]->numeraseregions; j++) {
889 /* walk the list of erase regions, count any changes */
890 if (subdev[i]->eraseregions[j].
891 erasesize != curr_erasesize) {
892 erase_region_p->offset = begin;
893 erase_region_p->erasesize =
894 curr_erasesize;
895 erase_region_p->numblocks =
896 (position -
897 begin) / curr_erasesize;
898 begin = position;
900 curr_erasesize =
901 subdev[i]->eraseregions[j].
902 erasesize;
903 ++erase_region_p;
904 }
905 position +=
906 subdev[i]->eraseregions[j].
907 numblocks * curr_erasesize;
908 }
909 }
910 }
911 /* Now write the final entry */
912 erase_region_p->offset = begin;
913 erase_region_p->erasesize = curr_erasesize;
914 erase_region_p->numblocks = (position - begin) / curr_erasesize;
915 }
917 return &concat->mtd;
918 }
920 /*
921 * This function destroys an MTD object obtained from concat_mtd_devs()
922 */
924 void mtd_concat_destroy(struct mtd_info *mtd)
925 {
926 struct mtd_concat *concat = CONCAT(mtd);
927 if (concat->mtd.numeraseregions)
928 kfree(concat->mtd.eraseregions);
929 kfree(concat);
930 }
932 EXPORT_SYMBOL(mtd_concat_create);
933 EXPORT_SYMBOL(mtd_concat_destroy);
935 MODULE_LICENSE("GPL");
936 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
937 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");