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Linux 4.1.16
[linux/fpc-iii.git] / drivers / mtd / mtd_blkdevs.c
blobdf7c6c70757a6c97b1546330a3b61cc33bdb4e6c
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 <asm/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 int 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->cmd_type != REQ_TYPE_FS)
88 return -EIO;
89
90 if (req->cmd_flags & REQ_FLUSH)
91 return tr->flush(dev);
92
93 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
94 get_capacity(req->rq_disk))
95 return -EIO;
96
97 if (req->cmd_flags & REQ_DISCARD)
98 return tr->discard(dev, block, nsect);
99
100 switch(rq_data_dir(req)) {
101 case READ:
102 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
103 if (tr->readsect(dev, block, buf))
104 return -EIO;
105 rq_flush_dcache_pages(req);
106 return 0;
107 case WRITE:
108 if (!tr->writesect)
109 return -EIO;
110
111 rq_flush_dcache_pages(req);
112 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
113 if (tr->writesect(dev, block, buf))
114 return -EIO;
115 return 0;
116 default:
117 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
118 return -EIO;
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 int 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, -ENODEV);
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(&dev->lock);
200 mutex_lock(&mtd_table_mutex);
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(&mtd_table_mutex);
225 mutex_unlock(&dev->lock);
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(&mtd_table_mutex);
236 mutex_unlock(&dev->lock);
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(&dev->lock);
249 mutex_lock(&mtd_table_mutex);
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(&mtd_table_mutex);
264 mutex_unlock(&dev->lock);
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) : 0;
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, (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_flush(new->rq, REQ_FLUSH);
417
418 new->rq->queuedata = new;
419 blk_queue_logical_block_size(new->rq, tr->blksize);
420
421 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq);
422 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, new->rq);
423
424 if (tr->discard) {
425 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
426 new->rq->limits.max_discard_sectors = UINT_MAX;
427 }
428
429 gd->queue = new->rq;
430
431 /* Create processing workqueue */
432 new->wq = alloc_workqueue("%s%d", 0, 0,
433 tr->name, new->mtd->index);
434 if (!new->wq)
435 goto error4;
436 INIT_WORK(&new->work, mtd_blktrans_work);
437
438 gd->driverfs_dev = &new->mtd->dev;
439
440 if (new->readonly)
441 set_disk_ro(gd, 1);
442
443 add_disk(gd);
444
445 if (new->disk_attributes) {
446 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
447 new->disk_attributes);
448 WARN_ON(ret);
449 }
450 return 0;
451 error4:
452 blk_cleanup_queue(new->rq);
453 error3:
454 put_disk(new->disk);
455 error2:
456 list_del(&new->list);
457 error1:
458 return ret;
459 }
460
461 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
462 {
463 unsigned long flags;
464
465 if (mutex_trylock(&mtd_table_mutex)) {
466 mutex_unlock(&mtd_table_mutex);
467 BUG();
468 }
469
470 if (old->disk_attributes)
471 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
472 old->disk_attributes);
473
474 /* Stop new requests to arrive */
475 del_gendisk(old->disk);
476
477 /* Stop workqueue. This will perform any pending request. */
478 destroy_workqueue(old->wq);
479
480 /* Kill current requests */
481 spin_lock_irqsave(&old->queue_lock, flags);
482 old->rq->queuedata = NULL;
483 blk_start_queue(old->rq);
484 spin_unlock_irqrestore(&old->queue_lock, flags);
485
486 /* If the device is currently open, tell trans driver to close it,
487 then put mtd device, and don't touch it again */
488 mutex_lock(&old->lock);
489 if (old->open) {
490 if (old->tr->release)
491 old->tr->release(old);
492 __put_mtd_device(old->mtd);
493 }
494
495 old->mtd = NULL;
496
497 mutex_unlock(&old->lock);
498 blktrans_dev_put(old);
499 return 0;
500 }
501
502 static void blktrans_notify_remove(struct mtd_info *mtd)
503 {
504 struct mtd_blktrans_ops *tr;
505 struct mtd_blktrans_dev *dev, *next;
506
507 list_for_each_entry(tr, &blktrans_majors, list)
508 list_for_each_entry_safe(dev, next, &tr->devs, list)
509 if (dev->mtd == mtd)
510 tr->remove_dev(dev);
511 }
512
513 static void blktrans_notify_add(struct mtd_info *mtd)
514 {
515 struct mtd_blktrans_ops *tr;
516
517 if (mtd->type == MTD_ABSENT)
518 return;
519
520 list_for_each_entry(tr, &blktrans_majors, list)
521 tr->add_mtd(tr, mtd);
522 }
523
524 static struct mtd_notifier blktrans_notifier = {
525 .add = blktrans_notify_add,
526 .remove = blktrans_notify_remove,
527 };
528
529 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
530 {
531 struct mtd_info *mtd;
532 int ret;
533
534 /* Register the notifier if/when the first device type is
535 registered, to prevent the link/init ordering from fucking
536 us over. */
537 if (!blktrans_notifier.list.next)
538 register_mtd_user(&blktrans_notifier);
539
540
541 mutex_lock(&mtd_table_mutex);
542
543 ret = register_blkdev(tr->major, tr->name);
544 if (ret < 0) {
545 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
546 tr->name, tr->major, ret);
547 mutex_unlock(&mtd_table_mutex);
548 return ret;
549 }
550
551 if (ret)
552 tr->major = ret;
553
554 tr->blkshift = ffs(tr->blksize) - 1;
555
556 INIT_LIST_HEAD(&tr->devs);
557 list_add(&tr->list, &blktrans_majors);
558
559 mtd_for_each_device(mtd)
560 if (mtd->type != MTD_ABSENT)
561 tr->add_mtd(tr, mtd);
562
563 mutex_unlock(&mtd_table_mutex);
564 return 0;
565 }
566
567 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
568 {
569 struct mtd_blktrans_dev *dev, *next;
570
571 mutex_lock(&mtd_table_mutex);
572
573 /* Remove it from the list of active majors */
574 list_del(&tr->list);
575
576 list_for_each_entry_safe(dev, next, &tr->devs, list)
577 tr->remove_dev(dev);
578
579 unregister_blkdev(tr->major, tr->name);
580 mutex_unlock(&mtd_table_mutex);
581
582 BUG_ON(!list_empty(&tr->devs));
583 return 0;
584 }
585
586 static void __exit mtd_blktrans_exit(void)
587 {
588 /* No race here -- if someone's currently in register_mtd_blktrans
589 we're screwed anyway. */
590 if (blktrans_notifier.list.next)
591 unregister_mtd_user(&blktrans_notifier);
592 }
593
594 module_exit(mtd_blktrans_exit);
595
596 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
597 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
598 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
599 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
600
601 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
602 MODULE_LICENSE("GPL");
603 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");
Linux with added FPC-III support