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LiteX: driver for MMCM
[linux/fpc-iii.git] / drivers / mtd / mtd_blkdevs.c
blobfb8e12d590a13ad30c3ecc7be51281e75b161266
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Interface to Linux block layer for MTD 'translation layers'.
4 *
5 * Copyright © 2003-2010 David Woodhouse <dwmw2@infradead.org>
6 */
7
8 #include <linux/kernel.h>
9 #include <linux/slab.h>
10 #include <linux/module.h>
11 #include <linux/list.h>
12 #include <linux/fs.h>
13 #include <linux/mtd/blktrans.h>
14 #include <linux/mtd/mtd.h>
15 #include <linux/blkdev.h>
16 #include <linux/blk-mq.h>
17 #include <linux/blkpg.h>
18 #include <linux/spinlock.h>
19 #include <linux/hdreg.h>
20 #include <linux/mutex.h>
21 #include <linux/uaccess.h>
22
23 #include "mtdcore.h"
24
25 static LIST_HEAD(blktrans_majors);
26 static DEFINE_MUTEX(blktrans_ref_mutex);
27
28 static void blktrans_dev_release(struct kref *kref)
29 {
30 struct mtd_blktrans_dev *dev =
31 container_of(kref, struct mtd_blktrans_dev, ref);
32
33 dev->disk->private_data = NULL;
34 blk_cleanup_queue(dev->rq);
35 blk_mq_free_tag_set(dev->tag_set);
36 kfree(dev->tag_set);
37 put_disk(dev->disk);
38 list_del(&dev->list);
39 kfree(dev);
40 }
41
42 static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
43 {
44 struct mtd_blktrans_dev *dev;
45
46 mutex_lock(&blktrans_ref_mutex);
47 dev = disk->private_data;
48
49 if (!dev)
50 goto unlock;
51 kref_get(&dev->ref);
52 unlock:
53 mutex_unlock(&blktrans_ref_mutex);
54 return dev;
55 }
56
57 static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
58 {
59 mutex_lock(&blktrans_ref_mutex);
60 kref_put(&dev->ref, blktrans_dev_release);
61 mutex_unlock(&blktrans_ref_mutex);
62 }
63
64
65 static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr,
66 struct mtd_blktrans_dev *dev,
67 struct request *req)
68 {
69 unsigned long block, nsect;
70 char *buf;
71
72 block = blk_rq_pos(req) << 9 >> tr->blkshift;
73 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
74
75 if (req_op(req) == REQ_OP_FLUSH) {
76 if (tr->flush(dev))
77 return BLK_STS_IOERR;
78 return BLK_STS_OK;
79 }
80
81 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
82 get_capacity(req->rq_disk))
83 return BLK_STS_IOERR;
84
85 switch (req_op(req)) {
86 case REQ_OP_DISCARD:
87 if (tr->discard(dev, block, nsect))
88 return BLK_STS_IOERR;
89 return BLK_STS_OK;
90 case REQ_OP_READ:
91 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
92 for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
93 if (tr->readsect(dev, block, buf)) {
94 kunmap(bio_page(req->bio));
95 return BLK_STS_IOERR;
96 }
97 }
98 kunmap(bio_page(req->bio));
99 rq_flush_dcache_pages(req);
100 return BLK_STS_OK;
101 case REQ_OP_WRITE:
102 if (!tr->writesect)
103 return BLK_STS_IOERR;
104
105 rq_flush_dcache_pages(req);
106 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
107 for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
108 if (tr->writesect(dev, block, buf)) {
109 kunmap(bio_page(req->bio));
110 return BLK_STS_IOERR;
111 }
112 }
113 kunmap(bio_page(req->bio));
114 return BLK_STS_OK;
115 default:
116 return BLK_STS_IOERR;
117 }
118 }
119
120 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
121 {
122 return dev->bg_stop;
123 }
124 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
125
126 static struct request *mtd_next_request(struct mtd_blktrans_dev *dev)
127 {
128 struct request *rq;
129
130 rq = list_first_entry_or_null(&dev->rq_list, struct request, queuelist);
131 if (rq) {
132 list_del_init(&rq->queuelist);
133 blk_mq_start_request(rq);
134 return rq;
135 }
136
137 return NULL;
138 }
139
140 static void mtd_blktrans_work(struct mtd_blktrans_dev *dev)
141 __releases(&dev->queue_lock)
142 __acquires(&dev->queue_lock)
143 {
144 struct mtd_blktrans_ops *tr = dev->tr;
145 struct request *req = NULL;
146 int background_done = 0;
147
148 while (1) {
149 blk_status_t res;
150
151 dev->bg_stop = false;
152 if (!req && !(req = mtd_next_request(dev))) {
153 if (tr->background && !background_done) {
154 spin_unlock_irq(&dev->queue_lock);
155 mutex_lock(&dev->lock);
156 tr->background(dev);
157 mutex_unlock(&dev->lock);
158 spin_lock_irq(&dev->queue_lock);
159 /*
160 * Do background processing just once per idle
161 * period.
162 */
163 background_done = !dev->bg_stop;
164 continue;
165 }
166 break;
167 }
168
169 spin_unlock_irq(&dev->queue_lock);
170
171 mutex_lock(&dev->lock);
172 res = do_blktrans_request(dev->tr, dev, req);
173 mutex_unlock(&dev->lock);
174
175 if (!blk_update_request(req, res, blk_rq_cur_bytes(req))) {
176 __blk_mq_end_request(req, res);
177 req = NULL;
178 }
179
180 background_done = 0;
181 spin_lock_irq(&dev->queue_lock);
182 }
183 }
184
185 static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx,
186 const struct blk_mq_queue_data *bd)
187 {
188 struct mtd_blktrans_dev *dev;
189
190 dev = hctx->queue->queuedata;
191 if (!dev) {
192 blk_mq_start_request(bd->rq);
193 return BLK_STS_IOERR;
194 }
195
196 spin_lock_irq(&dev->queue_lock);
197 list_add_tail(&bd->rq->queuelist, &dev->rq_list);
198 mtd_blktrans_work(dev);
199 spin_unlock_irq(&dev->queue_lock);
200
201 return BLK_STS_OK;
202 }
203
204 static int blktrans_open(struct block_device *bdev, fmode_t mode)
205 {
206 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
207 int ret = 0;
208
209 if (!dev)
210 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
211
212 mutex_lock(&mtd_table_mutex);
213 mutex_lock(&dev->lock);
214
215 if (dev->open)
216 goto unlock;
217
218 kref_get(&dev->ref);
219 __module_get(dev->tr->owner);
220
221 if (!dev->mtd)
222 goto unlock;
223
224 if (dev->tr->open) {
225 ret = dev->tr->open(dev);
226 if (ret)
227 goto error_put;
228 }
229
230 ret = __get_mtd_device(dev->mtd);
231 if (ret)
232 goto error_release;
233 dev->file_mode = mode;
234
235 unlock:
236 dev->open++;
237 mutex_unlock(&dev->lock);
238 mutex_unlock(&mtd_table_mutex);
239 blktrans_dev_put(dev);
240 return ret;
241
242 error_release:
243 if (dev->tr->release)
244 dev->tr->release(dev);
245 error_put:
246 module_put(dev->tr->owner);
247 kref_put(&dev->ref, blktrans_dev_release);
248 mutex_unlock(&dev->lock);
249 mutex_unlock(&mtd_table_mutex);
250 blktrans_dev_put(dev);
251 return ret;
252 }
253
254 static void blktrans_release(struct gendisk *disk, fmode_t mode)
255 {
256 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
257
258 if (!dev)
259 return;
260
261 mutex_lock(&mtd_table_mutex);
262 mutex_lock(&dev->lock);
263
264 if (--dev->open)
265 goto unlock;
266
267 kref_put(&dev->ref, blktrans_dev_release);
268 module_put(dev->tr->owner);
269
270 if (dev->mtd) {
271 if (dev->tr->release)
272 dev->tr->release(dev);
273 __put_mtd_device(dev->mtd);
274 }
275 unlock:
276 mutex_unlock(&dev->lock);
277 mutex_unlock(&mtd_table_mutex);
278 blktrans_dev_put(dev);
279 }
280
281 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
282 {
283 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
284 int ret = -ENXIO;
285
286 if (!dev)
287 return ret;
288
289 mutex_lock(&dev->lock);
290
291 if (!dev->mtd)
292 goto unlock;
293
294 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY;
295 unlock:
296 mutex_unlock(&dev->lock);
297 blktrans_dev_put(dev);
298 return ret;
299 }
300
301 static const struct block_device_operations mtd_block_ops = {
302 .owner = THIS_MODULE,
303 .open = blktrans_open,
304 .release = blktrans_release,
305 .getgeo = blktrans_getgeo,
306 };
307
308 static const struct blk_mq_ops mtd_mq_ops = {
309 .queue_rq = mtd_queue_rq,
310 };
311
312 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
313 {
314 struct mtd_blktrans_ops *tr = new->tr;
315 struct mtd_blktrans_dev *d;
316 int last_devnum = -1;
317 struct gendisk *gd;
318 int ret;
319
320 if (mutex_trylock(&mtd_table_mutex)) {
321 mutex_unlock(&mtd_table_mutex);
322 BUG();
323 }
324
325 mutex_lock(&blktrans_ref_mutex);
326 list_for_each_entry(d, &tr->devs, list) {
327 if (new->devnum == -1) {
328 /* Use first free number */
329 if (d->devnum != last_devnum+1) {
330 /* Found a free devnum. Plug it in here */
331 new->devnum = last_devnum+1;
332 list_add_tail(&new->list, &d->list);
333 goto added;
334 }
335 } else if (d->devnum == new->devnum) {
336 /* Required number taken */
337 mutex_unlock(&blktrans_ref_mutex);
338 return -EBUSY;
339 } else if (d->devnum > new->devnum) {
340 /* Required number was free */
341 list_add_tail(&new->list, &d->list);
342 goto added;
343 }
344 last_devnum = d->devnum;
345 }
346
347 ret = -EBUSY;
348 if (new->devnum == -1)
349 new->devnum = last_devnum+1;
350
351 /* Check that the device and any partitions will get valid
352 * minor numbers and that the disk naming code below can cope
353 * with this number. */
354 if (new->devnum > (MINORMASK >> tr->part_bits) ||
355 (tr->part_bits && new->devnum >= 27 * 26)) {
356 mutex_unlock(&blktrans_ref_mutex);
357 goto error1;
358 }
359
360 list_add_tail(&new->list, &tr->devs);
361 added:
362 mutex_unlock(&blktrans_ref_mutex);
363
364 mutex_init(&new->lock);
365 kref_init(&new->ref);
366 if (!tr->writesect)
367 new->readonly = 1;
368
369 /* Create gendisk */
370 ret = -ENOMEM;
371 gd = alloc_disk(1 << tr->part_bits);
372
373 if (!gd)
374 goto error2;
375
376 new->disk = gd;
377 gd->private_data = new;
378 gd->major = tr->major;
379 gd->first_minor = (new->devnum) << tr->part_bits;
380 gd->fops = &mtd_block_ops;
381
382 if (tr->part_bits)
383 if (new->devnum < 26)
384 snprintf(gd->disk_name, sizeof(gd->disk_name),
385 "%s%c", tr->name, 'a' + new->devnum);
386 else
387 snprintf(gd->disk_name, sizeof(gd->disk_name),
388 "%s%c%c", tr->name,
389 'a' - 1 + new->devnum / 26,
390 'a' + new->devnum % 26);
391 else
392 snprintf(gd->disk_name, sizeof(gd->disk_name),
393 "%s%d", tr->name, new->devnum);
394
395 set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);
396
397 /* Create the request queue */
398 spin_lock_init(&new->queue_lock);
399 INIT_LIST_HEAD(&new->rq_list);
400
401 new->tag_set = kzalloc(sizeof(*new->tag_set), GFP_KERNEL);
402 if (!new->tag_set)
403 goto error3;
404
405 new->rq = blk_mq_init_sq_queue(new->tag_set, &mtd_mq_ops, 2,
406 BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING);
407 if (IS_ERR(new->rq)) {
408 ret = PTR_ERR(new->rq);
409 new->rq = NULL;
410 goto error4;
411 }
412
413 if (tr->flush)
414 blk_queue_write_cache(new->rq, true, false);
415
416 new->rq->queuedata = new;
417 blk_queue_logical_block_size(new->rq, tr->blksize);
418
419 blk_queue_flag_set(QUEUE_FLAG_NONROT, new->rq);
420 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, new->rq);
421
422 if (tr->discard) {
423 blk_queue_flag_set(QUEUE_FLAG_DISCARD, new->rq);
424 blk_queue_max_discard_sectors(new->rq, UINT_MAX);
425 }
426
427 gd->queue = new->rq;
428
429 if (new->readonly)
430 set_disk_ro(gd, 1);
431
432 device_add_disk(&new->mtd->dev, gd, NULL);
433
434 if (new->disk_attributes) {
435 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
436 new->disk_attributes);
437 WARN_ON(ret);
438 }
439 return 0;
440 error4:
441 kfree(new->tag_set);
442 error3:
443 put_disk(new->disk);
444 error2:
445 list_del(&new->list);
446 error1:
447 return ret;
448 }
449
450 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
451 {
452 unsigned long flags;
453
454 if (mutex_trylock(&mtd_table_mutex)) {
455 mutex_unlock(&mtd_table_mutex);
456 BUG();
457 }
458
459 if (old->disk_attributes)
460 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
461 old->disk_attributes);
462
463 /* Stop new requests to arrive */
464 del_gendisk(old->disk);
465
466 /* Kill current requests */
467 spin_lock_irqsave(&old->queue_lock, flags);
468 old->rq->queuedata = NULL;
469 spin_unlock_irqrestore(&old->queue_lock, flags);
470
471 /* freeze+quiesce queue to ensure all requests are flushed */
472 blk_mq_freeze_queue(old->rq);
473 blk_mq_quiesce_queue(old->rq);
474 blk_mq_unquiesce_queue(old->rq);
475 blk_mq_unfreeze_queue(old->rq);
476
477 /* If the device is currently open, tell trans driver to close it,
478 then put mtd device, and don't touch it again */
479 mutex_lock(&old->lock);
480 if (old->open) {
481 if (old->tr->release)
482 old->tr->release(old);
483 __put_mtd_device(old->mtd);
484 }
485
486 old->mtd = NULL;
487
488 mutex_unlock(&old->lock);
489 blktrans_dev_put(old);
490 return 0;
491 }
492
493 static void blktrans_notify_remove(struct mtd_info *mtd)
494 {
495 struct mtd_blktrans_ops *tr;
496 struct mtd_blktrans_dev *dev, *next;
497
498 list_for_each_entry(tr, &blktrans_majors, list)
499 list_for_each_entry_safe(dev, next, &tr->devs, list)
500 if (dev->mtd == mtd)
501 tr->remove_dev(dev);
502 }
503
504 static void blktrans_notify_add(struct mtd_info *mtd)
505 {
506 struct mtd_blktrans_ops *tr;
507
508 if (mtd->type == MTD_ABSENT)
509 return;
510
511 list_for_each_entry(tr, &blktrans_majors, list)
512 tr->add_mtd(tr, mtd);
513 }
514
515 static struct mtd_notifier blktrans_notifier = {
516 .add = blktrans_notify_add,
517 .remove = blktrans_notify_remove,
518 };
519
520 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
521 {
522 struct mtd_info *mtd;
523 int ret;
524
525 /* Register the notifier if/when the first device type is
526 registered, to prevent the link/init ordering from fucking
527 us over. */
528 if (!blktrans_notifier.list.next)
529 register_mtd_user(&blktrans_notifier);
530
531
532 mutex_lock(&mtd_table_mutex);
533
534 ret = register_blkdev(tr->major, tr->name);
535 if (ret < 0) {
536 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
537 tr->name, tr->major, ret);
538 mutex_unlock(&mtd_table_mutex);
539 return ret;
540 }
541
542 if (ret)
543 tr->major = ret;
544
545 tr->blkshift = ffs(tr->blksize) - 1;
546
547 INIT_LIST_HEAD(&tr->devs);
548 list_add(&tr->list, &blktrans_majors);
549
550 mtd_for_each_device(mtd)
551 if (mtd->type != MTD_ABSENT)
552 tr->add_mtd(tr, mtd);
553
554 mutex_unlock(&mtd_table_mutex);
555 return 0;
556 }
557
558 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
559 {
560 struct mtd_blktrans_dev *dev, *next;
561
562 mutex_lock(&mtd_table_mutex);
563
564 /* Remove it from the list of active majors */
565 list_del(&tr->list);
566
567 list_for_each_entry_safe(dev, next, &tr->devs, list)
568 tr->remove_dev(dev);
569
570 unregister_blkdev(tr->major, tr->name);
571 mutex_unlock(&mtd_table_mutex);
572
573 BUG_ON(!list_empty(&tr->devs));
574 return 0;
575 }
576
577 static void __exit mtd_blktrans_exit(void)
578 {
579 /* No race here -- if someone's currently in register_mtd_blktrans
580 we're screwed anyway. */
581 if (blktrans_notifier.list.next)
582 unregister_mtd_user(&blktrans_notifier);
583 }
584
585 module_exit(mtd_blktrans_exit);
586
587 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
588 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
589 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
590 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
591
592 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
593 MODULE_LICENSE("GPL");
594 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");
Linux with added FPC-III support