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xtensa: support DMA buffers in high memory
[cris-mirror.git] / drivers / mtd / mtd_blkdevs.c
blob9ec8f033ac5f077b05fdfc32a7f97f1747339ca8
1 /*
2 * Interface to Linux block layer for MTD 'translation layers'.
3 *
4 * Copyright © 2003-2010 David Woodhouse <dwmw2@infradead.org>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 *
20 */
21
22 #include <linux/kernel.h>
23 #include <linux/slab.h>
24 #include <linux/module.h>
25 #include <linux/list.h>
26 #include <linux/fs.h>
27 #include <linux/mtd/blktrans.h>
28 #include <linux/mtd/mtd.h>
29 #include <linux/blkdev.h>
30 #include <linux/blkpg.h>
31 #include <linux/spinlock.h>
32 #include <linux/hdreg.h>
33 #include <linux/mutex.h>
34 #include <linux/uaccess.h>
35
36 #include "mtdcore.h"
37
38 static LIST_HEAD(blktrans_majors);
39 static DEFINE_MUTEX(blktrans_ref_mutex);
40
41 static void blktrans_dev_release(struct kref *kref)
42 {
43 struct mtd_blktrans_dev *dev =
44 container_of(kref, struct mtd_blktrans_dev, ref);
45
46 dev->disk->private_data = NULL;
47 blk_cleanup_queue(dev->rq);
48 put_disk(dev->disk);
49 list_del(&dev->list);
50 kfree(dev);
51 }
52
53 static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
54 {
55 struct mtd_blktrans_dev *dev;
56
57 mutex_lock(&blktrans_ref_mutex);
58 dev = disk->private_data;
59
60 if (!dev)
61 goto unlock;
62 kref_get(&dev->ref);
63 unlock:
64 mutex_unlock(&blktrans_ref_mutex);
65 return dev;
66 }
67
68 static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
69 {
70 mutex_lock(&blktrans_ref_mutex);
71 kref_put(&dev->ref, blktrans_dev_release);
72 mutex_unlock(&blktrans_ref_mutex);
73 }
74
75
76 static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr,
77 struct mtd_blktrans_dev *dev,
78 struct request *req)
79 {
80 unsigned long block, nsect;
81 char *buf;
82
83 block = blk_rq_pos(req) << 9 >> tr->blkshift;
84 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
85 buf = bio_data(req->bio);
86
87 if (req_op(req) == REQ_OP_FLUSH) {
88 if (tr->flush(dev))
89 return BLK_STS_IOERR;
90 return BLK_STS_OK;
91 }
92
93 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
94 get_capacity(req->rq_disk))
95 return BLK_STS_IOERR;
96
97 switch (req_op(req)) {
98 case REQ_OP_DISCARD:
99 if (tr->discard(dev, block, nsect))
100 return BLK_STS_IOERR;
101 return BLK_STS_OK;
102 case REQ_OP_READ:
103 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
104 if (tr->readsect(dev, block, buf))
105 return BLK_STS_IOERR;
106 rq_flush_dcache_pages(req);
107 return BLK_STS_OK;
108 case REQ_OP_WRITE:
109 if (!tr->writesect)
110 return BLK_STS_IOERR;
111
112 rq_flush_dcache_pages(req);
113 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
114 if (tr->writesect(dev, block, buf))
115 return BLK_STS_IOERR;
116 return BLK_STS_OK;
117 default:
118 return BLK_STS_IOERR;
119 }
120 }
121
122 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
123 {
124 return dev->bg_stop;
125 }
126 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
127
128 static void mtd_blktrans_work(struct work_struct *work)
129 {
130 struct mtd_blktrans_dev *dev =
131 container_of(work, struct mtd_blktrans_dev, work);
132 struct mtd_blktrans_ops *tr = dev->tr;
133 struct request_queue *rq = dev->rq;
134 struct request *req = NULL;
135 int background_done = 0;
136
137 spin_lock_irq(rq->queue_lock);
138
139 while (1) {
140 blk_status_t res;
141
142 dev->bg_stop = false;
143 if (!req && !(req = blk_fetch_request(rq))) {
144 if (tr->background && !background_done) {
145 spin_unlock_irq(rq->queue_lock);
146 mutex_lock(&dev->lock);
147 tr->background(dev);
148 mutex_unlock(&dev->lock);
149 spin_lock_irq(rq->queue_lock);
150 /*
151 * Do background processing just once per idle
152 * period.
153 */
154 background_done = !dev->bg_stop;
155 continue;
156 }
157 break;
158 }
159
160 spin_unlock_irq(rq->queue_lock);
161
162 mutex_lock(&dev->lock);
163 res = do_blktrans_request(dev->tr, dev, req);
164 mutex_unlock(&dev->lock);
165
166 spin_lock_irq(rq->queue_lock);
167
168 if (!__blk_end_request_cur(req, res))
169 req = NULL;
170
171 background_done = 0;
172 }
173
174 spin_unlock_irq(rq->queue_lock);
175 }
176
177 static void mtd_blktrans_request(struct request_queue *rq)
178 {
179 struct mtd_blktrans_dev *dev;
180 struct request *req = NULL;
181
182 dev = rq->queuedata;
183
184 if (!dev)
185 while ((req = blk_fetch_request(rq)) != NULL)
186 __blk_end_request_all(req, BLK_STS_IOERR);
187 else
188 queue_work(dev->wq, &dev->work);
189 }
190
191 static int blktrans_open(struct block_device *bdev, fmode_t mode)
192 {
193 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
194 int ret = 0;
195
196 if (!dev)
197 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
198
199 mutex_lock(&mtd_table_mutex);
200 mutex_lock(&dev->lock);
201
202 if (dev->open)
203 goto unlock;
204
205 kref_get(&dev->ref);
206 __module_get(dev->tr->owner);
207
208 if (!dev->mtd)
209 goto unlock;
210
211 if (dev->tr->open) {
212 ret = dev->tr->open(dev);
213 if (ret)
214 goto error_put;
215 }
216
217 ret = __get_mtd_device(dev->mtd);
218 if (ret)
219 goto error_release;
220 dev->file_mode = mode;
221
222 unlock:
223 dev->open++;
224 mutex_unlock(&dev->lock);
225 mutex_unlock(&mtd_table_mutex);
226 blktrans_dev_put(dev);
227 return ret;
228
229 error_release:
230 if (dev->tr->release)
231 dev->tr->release(dev);
232 error_put:
233 module_put(dev->tr->owner);
234 kref_put(&dev->ref, blktrans_dev_release);
235 mutex_unlock(&dev->lock);
236 mutex_unlock(&mtd_table_mutex);
237 blktrans_dev_put(dev);
238 return ret;
239 }
240
241 static void blktrans_release(struct gendisk *disk, fmode_t mode)
242 {
243 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
244
245 if (!dev)
246 return;
247
248 mutex_lock(&mtd_table_mutex);
249 mutex_lock(&dev->lock);
250
251 if (--dev->open)
252 goto unlock;
253
254 kref_put(&dev->ref, blktrans_dev_release);
255 module_put(dev->tr->owner);
256
257 if (dev->mtd) {
258 if (dev->tr->release)
259 dev->tr->release(dev);
260 __put_mtd_device(dev->mtd);
261 }
262 unlock:
263 mutex_unlock(&dev->lock);
264 mutex_unlock(&mtd_table_mutex);
265 blktrans_dev_put(dev);
266 }
267
268 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
269 {
270 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
271 int ret = -ENXIO;
272
273 if (!dev)
274 return ret;
275
276 mutex_lock(&dev->lock);
277
278 if (!dev->mtd)
279 goto unlock;
280
281 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY;
282 unlock:
283 mutex_unlock(&dev->lock);
284 blktrans_dev_put(dev);
285 return ret;
286 }
287
288 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
289 unsigned int cmd, unsigned long arg)
290 {
291 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
292 int ret = -ENXIO;
293
294 if (!dev)
295 return ret;
296
297 mutex_lock(&dev->lock);
298
299 if (!dev->mtd)
300 goto unlock;
301
302 switch (cmd) {
303 case BLKFLSBUF:
304 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
305 break;
306 default:
307 ret = -ENOTTY;
308 }
309 unlock:
310 mutex_unlock(&dev->lock);
311 blktrans_dev_put(dev);
312 return ret;
313 }
314
315 static const struct block_device_operations mtd_block_ops = {
316 .owner = THIS_MODULE,
317 .open = blktrans_open,
318 .release = blktrans_release,
319 .ioctl = blktrans_ioctl,
320 .getgeo = blktrans_getgeo,
321 };
322
323 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
324 {
325 struct mtd_blktrans_ops *tr = new->tr;
326 struct mtd_blktrans_dev *d;
327 int last_devnum = -1;
328 struct gendisk *gd;
329 int ret;
330
331 if (mutex_trylock(&mtd_table_mutex)) {
332 mutex_unlock(&mtd_table_mutex);
333 BUG();
334 }
335
336 mutex_lock(&blktrans_ref_mutex);
337 list_for_each_entry(d, &tr->devs, list) {
338 if (new->devnum == -1) {
339 /* Use first free number */
340 if (d->devnum != last_devnum+1) {
341 /* Found a free devnum. Plug it in here */
342 new->devnum = last_devnum+1;
343 list_add_tail(&new->list, &d->list);
344 goto added;
345 }
346 } else if (d->devnum == new->devnum) {
347 /* Required number taken */
348 mutex_unlock(&blktrans_ref_mutex);
349 return -EBUSY;
350 } else if (d->devnum > new->devnum) {
351 /* Required number was free */
352 list_add_tail(&new->list, &d->list);
353 goto added;
354 }
355 last_devnum = d->devnum;
356 }
357
358 ret = -EBUSY;
359 if (new->devnum == -1)
360 new->devnum = last_devnum+1;
361
362 /* Check that the device and any partitions will get valid
363 * minor numbers and that the disk naming code below can cope
364 * with this number. */
365 if (new->devnum > (MINORMASK >> tr->part_bits) ||
366 (tr->part_bits && new->devnum >= 27 * 26)) {
367 mutex_unlock(&blktrans_ref_mutex);
368 goto error1;
369 }
370
371 list_add_tail(&new->list, &tr->devs);
372 added:
373 mutex_unlock(&blktrans_ref_mutex);
374
375 mutex_init(&new->lock);
376 kref_init(&new->ref);
377 if (!tr->writesect)
378 new->readonly = 1;
379
380 /* Create gendisk */
381 ret = -ENOMEM;
382 gd = alloc_disk(1 << tr->part_bits);
383
384 if (!gd)
385 goto error2;
386
387 new->disk = gd;
388 gd->private_data = new;
389 gd->major = tr->major;
390 gd->first_minor = (new->devnum) << tr->part_bits;
391 gd->fops = &mtd_block_ops;
392
393 if (tr->part_bits)
394 if (new->devnum < 26)
395 snprintf(gd->disk_name, sizeof(gd->disk_name),
396 "%s%c", tr->name, 'a' + new->devnum);
397 else
398 snprintf(gd->disk_name, sizeof(gd->disk_name),
399 "%s%c%c", tr->name,
400 'a' - 1 + new->devnum / 26,
401 'a' + new->devnum % 26);
402 else
403 snprintf(gd->disk_name, sizeof(gd->disk_name),
404 "%s%d", tr->name, new->devnum);
405
406 set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);
407
408 /* Create the request queue */
409 spin_lock_init(&new->queue_lock);
410 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
411
412 if (!new->rq)
413 goto error3;
414
415 if (tr->flush)
416 blk_queue_write_cache(new->rq, true, false);
417
418 new->rq->queuedata = new;
419 blk_queue_logical_block_size(new->rq, tr->blksize);
420
421 blk_queue_bounce_limit(new->rq, BLK_BOUNCE_HIGH);
422 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq);
423 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, new->rq);
424
425 if (tr->discard) {
426 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
427 blk_queue_max_discard_sectors(new->rq, UINT_MAX);
428 }
429
430 gd->queue = new->rq;
431
432 /* Create processing workqueue */
433 new->wq = alloc_workqueue("%s%d", 0, 0,
434 tr->name, new->mtd->index);
435 if (!new->wq)
436 goto error4;
437 INIT_WORK(&new->work, mtd_blktrans_work);
438
439 if (new->readonly)
440 set_disk_ro(gd, 1);
441
442 device_add_disk(&new->mtd->dev, gd);
443
444 if (new->disk_attributes) {
445 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
446 new->disk_attributes);
447 WARN_ON(ret);
448 }
449 return 0;
450 error4:
451 blk_cleanup_queue(new->rq);
452 error3:
453 put_disk(new->disk);
454 error2:
455 list_del(&new->list);
456 error1:
457 return ret;
458 }
459
460 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
461 {
462 unsigned long flags;
463
464 if (mutex_trylock(&mtd_table_mutex)) {
465 mutex_unlock(&mtd_table_mutex);
466 BUG();
467 }
468
469 if (old->disk_attributes)
470 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
471 old->disk_attributes);
472
473 /* Stop new requests to arrive */
474 del_gendisk(old->disk);
475
476 /* Stop workqueue. This will perform any pending request. */
477 destroy_workqueue(old->wq);
478
479 /* Kill current requests */
480 spin_lock_irqsave(&old->queue_lock, flags);
481 old->rq->queuedata = NULL;
482 blk_start_queue(old->rq);
483 spin_unlock_irqrestore(&old->queue_lock, flags);
484
485 /* If the device is currently open, tell trans driver to close it,
486 then put mtd device, and don't touch it again */
487 mutex_lock(&old->lock);
488 if (old->open) {
489 if (old->tr->release)
490 old->tr->release(old);
491 __put_mtd_device(old->mtd);
492 }
493
494 old->mtd = NULL;
495
496 mutex_unlock(&old->lock);
497 blktrans_dev_put(old);
498 return 0;
499 }
500
501 static void blktrans_notify_remove(struct mtd_info *mtd)
502 {
503 struct mtd_blktrans_ops *tr;
504 struct mtd_blktrans_dev *dev, *next;
505
506 list_for_each_entry(tr, &blktrans_majors, list)
507 list_for_each_entry_safe(dev, next, &tr->devs, list)
508 if (dev->mtd == mtd)
509 tr->remove_dev(dev);
510 }
511
512 static void blktrans_notify_add(struct mtd_info *mtd)
513 {
514 struct mtd_blktrans_ops *tr;
515
516 if (mtd->type == MTD_ABSENT)
517 return;
518
519 list_for_each_entry(tr, &blktrans_majors, list)
520 tr->add_mtd(tr, mtd);
521 }
522
523 static struct mtd_notifier blktrans_notifier = {
524 .add = blktrans_notify_add,
525 .remove = blktrans_notify_remove,
526 };
527
528 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
529 {
530 struct mtd_info *mtd;
531 int ret;
532
533 /* Register the notifier if/when the first device type is
534 registered, to prevent the link/init ordering from fucking
535 us over. */
536 if (!blktrans_notifier.list.next)
537 register_mtd_user(&blktrans_notifier);
538
539
540 mutex_lock(&mtd_table_mutex);
541
542 ret = register_blkdev(tr->major, tr->name);
543 if (ret < 0) {
544 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
545 tr->name, tr->major, ret);
546 mutex_unlock(&mtd_table_mutex);
547 return ret;
548 }
549
550 if (ret)
551 tr->major = ret;
552
553 tr->blkshift = ffs(tr->blksize) - 1;
554
555 INIT_LIST_HEAD(&tr->devs);
556 list_add(&tr->list, &blktrans_majors);
557
558 mtd_for_each_device(mtd)
559 if (mtd->type != MTD_ABSENT)
560 tr->add_mtd(tr, mtd);
561
562 mutex_unlock(&mtd_table_mutex);
563 return 0;
564 }
565
566 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
567 {
568 struct mtd_blktrans_dev *dev, *next;
569
570 mutex_lock(&mtd_table_mutex);
571
572 /* Remove it from the list of active majors */
573 list_del(&tr->list);
574
575 list_for_each_entry_safe(dev, next, &tr->devs, list)
576 tr->remove_dev(dev);
577
578 unregister_blkdev(tr->major, tr->name);
579 mutex_unlock(&mtd_table_mutex);
580
581 BUG_ON(!list_empty(&tr->devs));
582 return 0;
583 }
584
585 static void __exit mtd_blktrans_exit(void)
586 {
587 /* No race here -- if someone's currently in register_mtd_blktrans
588 we're screwed anyway. */
589 if (blktrans_notifier.list.next)
590 unregister_mtd_user(&blktrans_notifier);
591 }
592
593 module_exit(mtd_blktrans_exit);
594
595 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
596 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
597 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
598 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
599
600 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
601 MODULE_LICENSE("GPL");
602 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");
CRIS linux kernel tree