xref: /linux/sound/core/control.c (revision a5766f11cfd3a0c03450d99c8fe548c2940be884)
1 /*
2  *  Routines for driver control interface
3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4  *
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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19  *
20  */
21 
22 #include <linux/threads.h>
23 #include <linux/interrupt.h>
24 #include <linux/slab.h>
25 #include <linux/vmalloc.h>
26 #include <linux/time.h>
27 #include <sound/core.h>
28 #include <sound/minors.h>
29 #include <sound/info.h>
30 #include <sound/control.h>
31 
32 /* max number of user-defined controls */
33 #define MAX_USER_CONTROLS	32
34 
35 struct snd_kctl_ioctl {
36 	struct list_head list;		/* list of all ioctls */
37 	snd_kctl_ioctl_func_t fioctl;
38 };
39 
40 static DECLARE_RWSEM(snd_ioctl_rwsem);
41 static LIST_HEAD(snd_control_ioctls);
42 #ifdef CONFIG_COMPAT
43 static LIST_HEAD(snd_control_compat_ioctls);
44 #endif
45 
46 static int snd_ctl_open(struct inode *inode, struct file *file)
47 {
48 	unsigned long flags;
49 	struct snd_card *card;
50 	struct snd_ctl_file *ctl;
51 	int err;
52 
53 	card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
54 	if (!card) {
55 		err = -ENODEV;
56 		goto __error1;
57 	}
58 	err = snd_card_file_add(card, file);
59 	if (err < 0) {
60 		err = -ENODEV;
61 		goto __error1;
62 	}
63 	if (!try_module_get(card->module)) {
64 		err = -EFAULT;
65 		goto __error2;
66 	}
67 	ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
68 	if (ctl == NULL) {
69 		err = -ENOMEM;
70 		goto __error;
71 	}
72 	INIT_LIST_HEAD(&ctl->events);
73 	init_waitqueue_head(&ctl->change_sleep);
74 	spin_lock_init(&ctl->read_lock);
75 	ctl->card = card;
76 	ctl->prefer_pcm_subdevice = -1;
77 	ctl->prefer_rawmidi_subdevice = -1;
78 	ctl->pid = current->pid;
79 	file->private_data = ctl;
80 	write_lock_irqsave(&card->ctl_files_rwlock, flags);
81 	list_add_tail(&ctl->list, &card->ctl_files);
82 	write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
83 	return 0;
84 
85       __error:
86 	module_put(card->module);
87       __error2:
88 	snd_card_file_remove(card, file);
89       __error1:
90       	return err;
91 }
92 
93 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
94 {
95 	unsigned long flags;
96 	struct snd_kctl_event *cread;
97 
98 	spin_lock_irqsave(&ctl->read_lock, flags);
99 	while (!list_empty(&ctl->events)) {
100 		cread = snd_kctl_event(ctl->events.next);
101 		list_del(&cread->list);
102 		kfree(cread);
103 	}
104 	spin_unlock_irqrestore(&ctl->read_lock, flags);
105 }
106 
107 static int snd_ctl_release(struct inode *inode, struct file *file)
108 {
109 	unsigned long flags;
110 	struct snd_card *card;
111 	struct snd_ctl_file *ctl;
112 	struct snd_kcontrol *control;
113 	unsigned int idx;
114 
115 	ctl = file->private_data;
116 	fasync_helper(-1, file, 0, &ctl->fasync);
117 	file->private_data = NULL;
118 	card = ctl->card;
119 	write_lock_irqsave(&card->ctl_files_rwlock, flags);
120 	list_del(&ctl->list);
121 	write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
122 	down_write(&card->controls_rwsem);
123 	list_for_each_entry(control, &card->controls, list)
124 		for (idx = 0; idx < control->count; idx++)
125 			if (control->vd[idx].owner == ctl)
126 				control->vd[idx].owner = NULL;
127 	up_write(&card->controls_rwsem);
128 	snd_ctl_empty_read_queue(ctl);
129 	kfree(ctl);
130 	module_put(card->module);
131 	snd_card_file_remove(card, file);
132 	return 0;
133 }
134 
135 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
136 		    struct snd_ctl_elem_id *id)
137 {
138 	unsigned long flags;
139 	struct snd_ctl_file *ctl;
140 	struct snd_kctl_event *ev;
141 
142 	if (snd_BUG_ON(!card || !id))
143 		return;
144 	read_lock(&card->ctl_files_rwlock);
145 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
146 	card->mixer_oss_change_count++;
147 #endif
148 	list_for_each_entry(ctl, &card->ctl_files, list) {
149 		if (!ctl->subscribed)
150 			continue;
151 		spin_lock_irqsave(&ctl->read_lock, flags);
152 		list_for_each_entry(ev, &ctl->events, list) {
153 			if (ev->id.numid == id->numid) {
154 				ev->mask |= mask;
155 				goto _found;
156 			}
157 		}
158 		ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
159 		if (ev) {
160 			ev->id = *id;
161 			ev->mask = mask;
162 			list_add_tail(&ev->list, &ctl->events);
163 		} else {
164 			snd_printk(KERN_ERR "No memory available to allocate event\n");
165 		}
166 	_found:
167 		wake_up(&ctl->change_sleep);
168 		spin_unlock_irqrestore(&ctl->read_lock, flags);
169 		kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
170 	}
171 	read_unlock(&card->ctl_files_rwlock);
172 }
173 
174 EXPORT_SYMBOL(snd_ctl_notify);
175 
176 /**
177  * snd_ctl_new - create a control instance from the template
178  * @control: the control template
179  * @access: the default control access
180  *
181  * Allocates a new struct snd_kcontrol instance and copies the given template
182  * to the new instance. It does not copy volatile data (access).
183  *
184  * Returns the pointer of the new instance, or NULL on failure.
185  */
186 static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control,
187 					unsigned int access)
188 {
189 	struct snd_kcontrol *kctl;
190 	unsigned int idx;
191 
192 	if (snd_BUG_ON(!control || !control->count))
193 		return NULL;
194 	kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL);
195 	if (kctl == NULL) {
196 		snd_printk(KERN_ERR "Cannot allocate control instance\n");
197 		return NULL;
198 	}
199 	*kctl = *control;
200 	for (idx = 0; idx < kctl->count; idx++)
201 		kctl->vd[idx].access = access;
202 	return kctl;
203 }
204 
205 /**
206  * snd_ctl_new1 - create a control instance from the template
207  * @ncontrol: the initialization record
208  * @private_data: the private data to set
209  *
210  * Allocates a new struct snd_kcontrol instance and initialize from the given
211  * template.  When the access field of ncontrol is 0, it's assumed as
212  * READWRITE access. When the count field is 0, it's assumes as one.
213  *
214  * Returns the pointer of the newly generated instance, or NULL on failure.
215  */
216 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
217 				  void *private_data)
218 {
219 	struct snd_kcontrol kctl;
220 	unsigned int access;
221 
222 	if (snd_BUG_ON(!ncontrol || !ncontrol->info))
223 		return NULL;
224 	memset(&kctl, 0, sizeof(kctl));
225 	kctl.id.iface = ncontrol->iface;
226 	kctl.id.device = ncontrol->device;
227 	kctl.id.subdevice = ncontrol->subdevice;
228 	if (ncontrol->name)
229 		strlcpy(kctl.id.name, ncontrol->name, sizeof(kctl.id.name));
230 	kctl.id.index = ncontrol->index;
231 	kctl.count = ncontrol->count ? ncontrol->count : 1;
232 	access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
233 		 (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
234 				      SNDRV_CTL_ELEM_ACCESS_INACTIVE|
235 		 		      SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE|
236 		 		      SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK));
237 	kctl.info = ncontrol->info;
238 	kctl.get = ncontrol->get;
239 	kctl.put = ncontrol->put;
240 	kctl.tlv.p = ncontrol->tlv.p;
241 	kctl.private_value = ncontrol->private_value;
242 	kctl.private_data = private_data;
243 	return snd_ctl_new(&kctl, access);
244 }
245 
246 EXPORT_SYMBOL(snd_ctl_new1);
247 
248 /**
249  * snd_ctl_free_one - release the control instance
250  * @kcontrol: the control instance
251  *
252  * Releases the control instance created via snd_ctl_new()
253  * or snd_ctl_new1().
254  * Don't call this after the control was added to the card.
255  */
256 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
257 {
258 	if (kcontrol) {
259 		if (kcontrol->private_free)
260 			kcontrol->private_free(kcontrol);
261 		kfree(kcontrol);
262 	}
263 }
264 
265 EXPORT_SYMBOL(snd_ctl_free_one);
266 
267 static unsigned int snd_ctl_hole_check(struct snd_card *card,
268 				       unsigned int count)
269 {
270 	struct snd_kcontrol *kctl;
271 
272 	list_for_each_entry(kctl, &card->controls, list) {
273 		if ((kctl->id.numid <= card->last_numid &&
274 		     kctl->id.numid + kctl->count > card->last_numid) ||
275 		    (kctl->id.numid <= card->last_numid + count - 1 &&
276 		     kctl->id.numid + kctl->count > card->last_numid + count - 1))
277 		    	return card->last_numid = kctl->id.numid + kctl->count - 1;
278 	}
279 	return card->last_numid;
280 }
281 
282 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
283 {
284 	unsigned int last_numid, iter = 100000;
285 
286 	last_numid = card->last_numid;
287 	while (last_numid != snd_ctl_hole_check(card, count)) {
288 		if (--iter == 0) {
289 			/* this situation is very unlikely */
290 			snd_printk(KERN_ERR "unable to allocate new control numid\n");
291 			return -ENOMEM;
292 		}
293 		last_numid = card->last_numid;
294 	}
295 	return 0;
296 }
297 
298 /**
299  * snd_ctl_add - add the control instance to the card
300  * @card: the card instance
301  * @kcontrol: the control instance to add
302  *
303  * Adds the control instance created via snd_ctl_new() or
304  * snd_ctl_new1() to the given card. Assigns also an unique
305  * numid used for fast search.
306  *
307  * Returns zero if successful, or a negative error code on failure.
308  *
309  * It frees automatically the control which cannot be added.
310  */
311 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
312 {
313 	struct snd_ctl_elem_id id;
314 	unsigned int idx;
315 	int err = -EINVAL;
316 
317 	if (! kcontrol)
318 		return err;
319 	if (snd_BUG_ON(!card || !kcontrol->info))
320 		goto error;
321 	id = kcontrol->id;
322 	down_write(&card->controls_rwsem);
323 	if (snd_ctl_find_id(card, &id)) {
324 		up_write(&card->controls_rwsem);
325 		snd_printd(KERN_ERR "control %i:%i:%i:%s:%i is already present\n",
326 					id.iface,
327 					id.device,
328 					id.subdevice,
329 					id.name,
330 					id.index);
331 		err = -EBUSY;
332 		goto error;
333 	}
334 	if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
335 		up_write(&card->controls_rwsem);
336 		err = -ENOMEM;
337 		goto error;
338 	}
339 	list_add_tail(&kcontrol->list, &card->controls);
340 	card->controls_count += kcontrol->count;
341 	kcontrol->id.numid = card->last_numid + 1;
342 	card->last_numid += kcontrol->count;
343 	up_write(&card->controls_rwsem);
344 	for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
345 		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
346 	return 0;
347 
348  error:
349 	snd_ctl_free_one(kcontrol);
350 	return err;
351 }
352 
353 EXPORT_SYMBOL(snd_ctl_add);
354 
355 /**
356  * snd_ctl_remove - remove the control from the card and release it
357  * @card: the card instance
358  * @kcontrol: the control instance to remove
359  *
360  * Removes the control from the card and then releases the instance.
361  * You don't need to call snd_ctl_free_one(). You must be in
362  * the write lock - down_write(&card->controls_rwsem).
363  *
364  * Returns 0 if successful, or a negative error code on failure.
365  */
366 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
367 {
368 	struct snd_ctl_elem_id id;
369 	unsigned int idx;
370 
371 	if (snd_BUG_ON(!card || !kcontrol))
372 		return -EINVAL;
373 	list_del(&kcontrol->list);
374 	card->controls_count -= kcontrol->count;
375 	id = kcontrol->id;
376 	for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
377 		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
378 	snd_ctl_free_one(kcontrol);
379 	return 0;
380 }
381 
382 EXPORT_SYMBOL(snd_ctl_remove);
383 
384 /**
385  * snd_ctl_remove_id - remove the control of the given id and release it
386  * @card: the card instance
387  * @id: the control id to remove
388  *
389  * Finds the control instance with the given id, removes it from the
390  * card list and releases it.
391  *
392  * Returns 0 if successful, or a negative error code on failure.
393  */
394 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
395 {
396 	struct snd_kcontrol *kctl;
397 	int ret;
398 
399 	down_write(&card->controls_rwsem);
400 	kctl = snd_ctl_find_id(card, id);
401 	if (kctl == NULL) {
402 		up_write(&card->controls_rwsem);
403 		return -ENOENT;
404 	}
405 	ret = snd_ctl_remove(card, kctl);
406 	up_write(&card->controls_rwsem);
407 	return ret;
408 }
409 
410 EXPORT_SYMBOL(snd_ctl_remove_id);
411 
412 /**
413  * snd_ctl_remove_unlocked_id - remove the unlocked control of the given id and release it
414  * @file: active control handle
415  * @id: the control id to remove
416  *
417  * Finds the control instance with the given id, removes it from the
418  * card list and releases it.
419  *
420  * Returns 0 if successful, or a negative error code on failure.
421  */
422 static int snd_ctl_remove_unlocked_id(struct snd_ctl_file * file,
423 				      struct snd_ctl_elem_id *id)
424 {
425 	struct snd_card *card = file->card;
426 	struct snd_kcontrol *kctl;
427 	int idx, ret;
428 
429 	down_write(&card->controls_rwsem);
430 	kctl = snd_ctl_find_id(card, id);
431 	if (kctl == NULL) {
432 		up_write(&card->controls_rwsem);
433 		return -ENOENT;
434 	}
435 	for (idx = 0; idx < kctl->count; idx++)
436 		if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
437 			up_write(&card->controls_rwsem);
438 			return -EBUSY;
439 		}
440 	ret = snd_ctl_remove(card, kctl);
441 	up_write(&card->controls_rwsem);
442 	return ret;
443 }
444 
445 /**
446  * snd_ctl_rename_id - replace the id of a control on the card
447  * @card: the card instance
448  * @src_id: the old id
449  * @dst_id: the new id
450  *
451  * Finds the control with the old id from the card, and replaces the
452  * id with the new one.
453  *
454  * Returns zero if successful, or a negative error code on failure.
455  */
456 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
457 		      struct snd_ctl_elem_id *dst_id)
458 {
459 	struct snd_kcontrol *kctl;
460 
461 	down_write(&card->controls_rwsem);
462 	kctl = snd_ctl_find_id(card, src_id);
463 	if (kctl == NULL) {
464 		up_write(&card->controls_rwsem);
465 		return -ENOENT;
466 	}
467 	kctl->id = *dst_id;
468 	kctl->id.numid = card->last_numid + 1;
469 	card->last_numid += kctl->count;
470 	up_write(&card->controls_rwsem);
471 	return 0;
472 }
473 
474 EXPORT_SYMBOL(snd_ctl_rename_id);
475 
476 /**
477  * snd_ctl_find_numid - find the control instance with the given number-id
478  * @card: the card instance
479  * @numid: the number-id to search
480  *
481  * Finds the control instance with the given number-id from the card.
482  *
483  * Returns the pointer of the instance if found, or NULL if not.
484  *
485  * The caller must down card->controls_rwsem before calling this function
486  * (if the race condition can happen).
487  */
488 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
489 {
490 	struct snd_kcontrol *kctl;
491 
492 	if (snd_BUG_ON(!card || !numid))
493 		return NULL;
494 	list_for_each_entry(kctl, &card->controls, list) {
495 		if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
496 			return kctl;
497 	}
498 	return NULL;
499 }
500 
501 EXPORT_SYMBOL(snd_ctl_find_numid);
502 
503 /**
504  * snd_ctl_find_id - find the control instance with the given id
505  * @card: the card instance
506  * @id: the id to search
507  *
508  * Finds the control instance with the given id from the card.
509  *
510  * Returns the pointer of the instance if found, or NULL if not.
511  *
512  * The caller must down card->controls_rwsem before calling this function
513  * (if the race condition can happen).
514  */
515 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
516 				     struct snd_ctl_elem_id *id)
517 {
518 	struct snd_kcontrol *kctl;
519 
520 	if (snd_BUG_ON(!card || !id))
521 		return NULL;
522 	if (id->numid != 0)
523 		return snd_ctl_find_numid(card, id->numid);
524 	list_for_each_entry(kctl, &card->controls, list) {
525 		if (kctl->id.iface != id->iface)
526 			continue;
527 		if (kctl->id.device != id->device)
528 			continue;
529 		if (kctl->id.subdevice != id->subdevice)
530 			continue;
531 		if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
532 			continue;
533 		if (kctl->id.index > id->index)
534 			continue;
535 		if (kctl->id.index + kctl->count <= id->index)
536 			continue;
537 		return kctl;
538 	}
539 	return NULL;
540 }
541 
542 EXPORT_SYMBOL(snd_ctl_find_id);
543 
544 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
545 			     unsigned int cmd, void __user *arg)
546 {
547 	struct snd_ctl_card_info *info;
548 
549 	info = kzalloc(sizeof(*info), GFP_KERNEL);
550 	if (! info)
551 		return -ENOMEM;
552 	down_read(&snd_ioctl_rwsem);
553 	info->card = card->number;
554 	strlcpy(info->id, card->id, sizeof(info->id));
555 	strlcpy(info->driver, card->driver, sizeof(info->driver));
556 	strlcpy(info->name, card->shortname, sizeof(info->name));
557 	strlcpy(info->longname, card->longname, sizeof(info->longname));
558 	strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
559 	strlcpy(info->components, card->components, sizeof(info->components));
560 	up_read(&snd_ioctl_rwsem);
561 	if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
562 		kfree(info);
563 		return -EFAULT;
564 	}
565 	kfree(info);
566 	return 0;
567 }
568 
569 static int snd_ctl_elem_list(struct snd_card *card,
570 			     struct snd_ctl_elem_list __user *_list)
571 {
572 	struct list_head *plist;
573 	struct snd_ctl_elem_list list;
574 	struct snd_kcontrol *kctl;
575 	struct snd_ctl_elem_id *dst, *id;
576 	unsigned int offset, space, first, jidx;
577 
578 	if (copy_from_user(&list, _list, sizeof(list)))
579 		return -EFAULT;
580 	offset = list.offset;
581 	space = list.space;
582 	first = 0;
583 	/* try limit maximum space */
584 	if (space > 16384)
585 		return -ENOMEM;
586 	if (space > 0) {
587 		/* allocate temporary buffer for atomic operation */
588 		dst = vmalloc(space * sizeof(struct snd_ctl_elem_id));
589 		if (dst == NULL)
590 			return -ENOMEM;
591 		down_read(&card->controls_rwsem);
592 		list.count = card->controls_count;
593 		plist = card->controls.next;
594 		while (plist != &card->controls) {
595 			if (offset == 0)
596 				break;
597 			kctl = snd_kcontrol(plist);
598 			if (offset < kctl->count)
599 				break;
600 			offset -= kctl->count;
601 			plist = plist->next;
602 		}
603 		list.used = 0;
604 		id = dst;
605 		while (space > 0 && plist != &card->controls) {
606 			kctl = snd_kcontrol(plist);
607 			for (jidx = offset; space > 0 && jidx < kctl->count; jidx++) {
608 				snd_ctl_build_ioff(id, kctl, jidx);
609 				id++;
610 				space--;
611 				list.used++;
612 			}
613 			plist = plist->next;
614 			offset = 0;
615 		}
616 		up_read(&card->controls_rwsem);
617 		if (list.used > 0 &&
618 		    copy_to_user(list.pids, dst,
619 				 list.used * sizeof(struct snd_ctl_elem_id))) {
620 			vfree(dst);
621 			return -EFAULT;
622 		}
623 		vfree(dst);
624 	} else {
625 		down_read(&card->controls_rwsem);
626 		list.count = card->controls_count;
627 		up_read(&card->controls_rwsem);
628 	}
629 	if (copy_to_user(_list, &list, sizeof(list)))
630 		return -EFAULT;
631 	return 0;
632 }
633 
634 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
635 			     struct snd_ctl_elem_info *info)
636 {
637 	struct snd_card *card = ctl->card;
638 	struct snd_kcontrol *kctl;
639 	struct snd_kcontrol_volatile *vd;
640 	unsigned int index_offset;
641 	int result;
642 
643 	down_read(&card->controls_rwsem);
644 	kctl = snd_ctl_find_id(card, &info->id);
645 	if (kctl == NULL) {
646 		up_read(&card->controls_rwsem);
647 		return -ENOENT;
648 	}
649 #ifdef CONFIG_SND_DEBUG
650 	info->access = 0;
651 #endif
652 	result = kctl->info(kctl, info);
653 	if (result >= 0) {
654 		snd_BUG_ON(info->access);
655 		index_offset = snd_ctl_get_ioff(kctl, &info->id);
656 		vd = &kctl->vd[index_offset];
657 		snd_ctl_build_ioff(&info->id, kctl, index_offset);
658 		info->access = vd->access;
659 		if (vd->owner) {
660 			info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
661 			if (vd->owner == ctl)
662 				info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
663 			info->owner = vd->owner_pid;
664 		} else {
665 			info->owner = -1;
666 		}
667 	}
668 	up_read(&card->controls_rwsem);
669 	return result;
670 }
671 
672 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
673 				  struct snd_ctl_elem_info __user *_info)
674 {
675 	struct snd_ctl_elem_info info;
676 	int result;
677 
678 	if (copy_from_user(&info, _info, sizeof(info)))
679 		return -EFAULT;
680 	snd_power_lock(ctl->card);
681 	result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
682 	if (result >= 0)
683 		result = snd_ctl_elem_info(ctl, &info);
684 	snd_power_unlock(ctl->card);
685 	if (result >= 0)
686 		if (copy_to_user(_info, &info, sizeof(info)))
687 			return -EFAULT;
688 	return result;
689 }
690 
691 static int snd_ctl_elem_read(struct snd_card *card,
692 			     struct snd_ctl_elem_value *control)
693 {
694 	struct snd_kcontrol *kctl;
695 	struct snd_kcontrol_volatile *vd;
696 	unsigned int index_offset;
697 	int result;
698 
699 	down_read(&card->controls_rwsem);
700 	kctl = snd_ctl_find_id(card, &control->id);
701 	if (kctl == NULL) {
702 		result = -ENOENT;
703 	} else {
704 		index_offset = snd_ctl_get_ioff(kctl, &control->id);
705 		vd = &kctl->vd[index_offset];
706 		if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) &&
707 		    kctl->get != NULL) {
708 			snd_ctl_build_ioff(&control->id, kctl, index_offset);
709 			result = kctl->get(kctl, control);
710 		} else
711 			result = -EPERM;
712 	}
713 	up_read(&card->controls_rwsem);
714 	return result;
715 }
716 
717 static int snd_ctl_elem_read_user(struct snd_card *card,
718 				  struct snd_ctl_elem_value __user *_control)
719 {
720 	struct snd_ctl_elem_value *control;
721 	int result;
722 
723 	control = kmalloc(sizeof(*control), GFP_KERNEL);
724 	if (control == NULL)
725 		return -ENOMEM;
726 	if (copy_from_user(control, _control, sizeof(*control))) {
727 		kfree(control);
728 		return -EFAULT;
729 	}
730 	snd_power_lock(card);
731 	result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
732 	if (result >= 0)
733 		result = snd_ctl_elem_read(card, control);
734 	snd_power_unlock(card);
735 	if (result >= 0)
736 		if (copy_to_user(_control, control, sizeof(*control)))
737 			result = -EFAULT;
738 	kfree(control);
739 	return result;
740 }
741 
742 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
743 			      struct snd_ctl_elem_value *control)
744 {
745 	struct snd_kcontrol *kctl;
746 	struct snd_kcontrol_volatile *vd;
747 	unsigned int index_offset;
748 	int result;
749 
750 	down_read(&card->controls_rwsem);
751 	kctl = snd_ctl_find_id(card, &control->id);
752 	if (kctl == NULL) {
753 		result = -ENOENT;
754 	} else {
755 		index_offset = snd_ctl_get_ioff(kctl, &control->id);
756 		vd = &kctl->vd[index_offset];
757 		if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
758 		    kctl->put == NULL ||
759 		    (file && vd->owner && vd->owner != file)) {
760 			result = -EPERM;
761 		} else {
762 			snd_ctl_build_ioff(&control->id, kctl, index_offset);
763 			result = kctl->put(kctl, control);
764 		}
765 		if (result > 0) {
766 			up_read(&card->controls_rwsem);
767 			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
768 				       &control->id);
769 			return 0;
770 		}
771 	}
772 	up_read(&card->controls_rwsem);
773 	return result;
774 }
775 
776 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
777 				   struct snd_ctl_elem_value __user *_control)
778 {
779 	struct snd_ctl_elem_value *control;
780 	struct snd_card *card;
781 	int result;
782 
783 	control = kmalloc(sizeof(*control), GFP_KERNEL);
784 	if (control == NULL)
785 		return -ENOMEM;
786 	if (copy_from_user(control, _control, sizeof(*control))) {
787 		kfree(control);
788 		return -EFAULT;
789 	}
790 	card = file->card;
791 	snd_power_lock(card);
792 	result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
793 	if (result >= 0)
794 		result = snd_ctl_elem_write(card, file, control);
795 	snd_power_unlock(card);
796 	if (result >= 0)
797 		if (copy_to_user(_control, control, sizeof(*control)))
798 			result = -EFAULT;
799 	kfree(control);
800 	return result;
801 }
802 
803 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
804 			     struct snd_ctl_elem_id __user *_id)
805 {
806 	struct snd_card *card = file->card;
807 	struct snd_ctl_elem_id id;
808 	struct snd_kcontrol *kctl;
809 	struct snd_kcontrol_volatile *vd;
810 	int result;
811 
812 	if (copy_from_user(&id, _id, sizeof(id)))
813 		return -EFAULT;
814 	down_write(&card->controls_rwsem);
815 	kctl = snd_ctl_find_id(card, &id);
816 	if (kctl == NULL) {
817 		result = -ENOENT;
818 	} else {
819 		vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
820 		if (vd->owner != NULL)
821 			result = -EBUSY;
822 		else {
823 			vd->owner = file;
824 			vd->owner_pid = current->pid;
825 			result = 0;
826 		}
827 	}
828 	up_write(&card->controls_rwsem);
829 	return result;
830 }
831 
832 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
833 			       struct snd_ctl_elem_id __user *_id)
834 {
835 	struct snd_card *card = file->card;
836 	struct snd_ctl_elem_id id;
837 	struct snd_kcontrol *kctl;
838 	struct snd_kcontrol_volatile *vd;
839 	int result;
840 
841 	if (copy_from_user(&id, _id, sizeof(id)))
842 		return -EFAULT;
843 	down_write(&card->controls_rwsem);
844 	kctl = snd_ctl_find_id(card, &id);
845 	if (kctl == NULL) {
846 		result = -ENOENT;
847 	} else {
848 		vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
849 		if (vd->owner == NULL)
850 			result = -EINVAL;
851 		else if (vd->owner != file)
852 			result = -EPERM;
853 		else {
854 			vd->owner = NULL;
855 			vd->owner_pid = 0;
856 			result = 0;
857 		}
858 	}
859 	up_write(&card->controls_rwsem);
860 	return result;
861 }
862 
863 struct user_element {
864 	struct snd_ctl_elem_info info;
865 	void *elem_data;		/* element data */
866 	unsigned long elem_data_size;	/* size of element data in bytes */
867 	void *tlv_data;			/* TLV data */
868 	unsigned long tlv_data_size;	/* TLV data size */
869 	void *priv_data;		/* private data (like strings for enumerated type) */
870 	unsigned long priv_data_size;	/* size of private data in bytes */
871 };
872 
873 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
874 				  struct snd_ctl_elem_info *uinfo)
875 {
876 	struct user_element *ue = kcontrol->private_data;
877 
878 	*uinfo = ue->info;
879 	return 0;
880 }
881 
882 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
883 				 struct snd_ctl_elem_value *ucontrol)
884 {
885 	struct user_element *ue = kcontrol->private_data;
886 
887 	memcpy(&ucontrol->value, ue->elem_data, ue->elem_data_size);
888 	return 0;
889 }
890 
891 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
892 				 struct snd_ctl_elem_value *ucontrol)
893 {
894 	int change;
895 	struct user_element *ue = kcontrol->private_data;
896 
897 	change = memcmp(&ucontrol->value, ue->elem_data, ue->elem_data_size) != 0;
898 	if (change)
899 		memcpy(ue->elem_data, &ucontrol->value, ue->elem_data_size);
900 	return change;
901 }
902 
903 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol,
904 				 int op_flag,
905 				 unsigned int size,
906 				 unsigned int __user *tlv)
907 {
908 	struct user_element *ue = kcontrol->private_data;
909 	int change = 0;
910 	void *new_data;
911 
912 	if (op_flag > 0) {
913 		if (size > 1024 * 128)	/* sane value */
914 			return -EINVAL;
915 		new_data = kmalloc(size, GFP_KERNEL);
916 		if (new_data == NULL)
917 			return -ENOMEM;
918 		if (copy_from_user(new_data, tlv, size)) {
919 			kfree(new_data);
920 			return -EFAULT;
921 		}
922 		change = ue->tlv_data_size != size;
923 		if (!change)
924 			change = memcmp(ue->tlv_data, new_data, size);
925 		kfree(ue->tlv_data);
926 		ue->tlv_data = new_data;
927 		ue->tlv_data_size = size;
928 	} else {
929 		if (! ue->tlv_data_size || ! ue->tlv_data)
930 			return -ENXIO;
931 		if (size < ue->tlv_data_size)
932 			return -ENOSPC;
933 		if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size))
934 			return -EFAULT;
935 	}
936 	return change;
937 }
938 
939 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
940 {
941 	struct user_element *ue = kcontrol->private_data;
942 	if (ue->tlv_data)
943 		kfree(ue->tlv_data);
944 	kfree(ue);
945 }
946 
947 static int snd_ctl_elem_add(struct snd_ctl_file *file,
948 			    struct snd_ctl_elem_info *info, int replace)
949 {
950 	struct snd_card *card = file->card;
951 	struct snd_kcontrol kctl, *_kctl;
952 	unsigned int access;
953 	long private_size;
954 	struct user_element *ue;
955 	int idx, err;
956 
957 	if (card->user_ctl_count >= MAX_USER_CONTROLS)
958 		return -ENOMEM;
959 	if (info->count > 1024)
960 		return -EINVAL;
961 	access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
962 		(info->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
963 				 SNDRV_CTL_ELEM_ACCESS_INACTIVE|
964 				 SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE));
965 	info->id.numid = 0;
966 	memset(&kctl, 0, sizeof(kctl));
967 	down_write(&card->controls_rwsem);
968 	_kctl = snd_ctl_find_id(card, &info->id);
969 	err = 0;
970 	if (_kctl) {
971 		if (replace)
972 			err = snd_ctl_remove(card, _kctl);
973 		else
974 			err = -EBUSY;
975 	} else {
976 		if (replace)
977 			err = -ENOENT;
978 	}
979 	up_write(&card->controls_rwsem);
980 	if (err < 0)
981 		return err;
982 	memcpy(&kctl.id, &info->id, sizeof(info->id));
983 	kctl.count = info->owner ? info->owner : 1;
984 	access |= SNDRV_CTL_ELEM_ACCESS_USER;
985 	kctl.info = snd_ctl_elem_user_info;
986 	if (access & SNDRV_CTL_ELEM_ACCESS_READ)
987 		kctl.get = snd_ctl_elem_user_get;
988 	if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
989 		kctl.put = snd_ctl_elem_user_put;
990 	if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE) {
991 		kctl.tlv.c = snd_ctl_elem_user_tlv;
992 		access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
993 	}
994 	switch (info->type) {
995 	case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
996 	case SNDRV_CTL_ELEM_TYPE_INTEGER:
997 		private_size = sizeof(long);
998 		if (info->count > 128)
999 			return -EINVAL;
1000 		break;
1001 	case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1002 		private_size = sizeof(long long);
1003 		if (info->count > 64)
1004 			return -EINVAL;
1005 		break;
1006 	case SNDRV_CTL_ELEM_TYPE_BYTES:
1007 		private_size = sizeof(unsigned char);
1008 		if (info->count > 512)
1009 			return -EINVAL;
1010 		break;
1011 	case SNDRV_CTL_ELEM_TYPE_IEC958:
1012 		private_size = sizeof(struct snd_aes_iec958);
1013 		if (info->count != 1)
1014 			return -EINVAL;
1015 		break;
1016 	default:
1017 		return -EINVAL;
1018 	}
1019 	private_size *= info->count;
1020 	ue = kzalloc(sizeof(struct user_element) + private_size, GFP_KERNEL);
1021 	if (ue == NULL)
1022 		return -ENOMEM;
1023 	ue->info = *info;
1024 	ue->info.access = 0;
1025 	ue->elem_data = (char *)ue + sizeof(*ue);
1026 	ue->elem_data_size = private_size;
1027 	kctl.private_free = snd_ctl_elem_user_free;
1028 	_kctl = snd_ctl_new(&kctl, access);
1029 	if (_kctl == NULL) {
1030 		kfree(ue);
1031 		return -ENOMEM;
1032 	}
1033 	_kctl->private_data = ue;
1034 	for (idx = 0; idx < _kctl->count; idx++)
1035 		_kctl->vd[idx].owner = file;
1036 	err = snd_ctl_add(card, _kctl);
1037 	if (err < 0)
1038 		return err;
1039 
1040 	down_write(&card->controls_rwsem);
1041 	card->user_ctl_count++;
1042 	up_write(&card->controls_rwsem);
1043 
1044 	return 0;
1045 }
1046 
1047 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1048 				 struct snd_ctl_elem_info __user *_info, int replace)
1049 {
1050 	struct snd_ctl_elem_info info;
1051 	if (copy_from_user(&info, _info, sizeof(info)))
1052 		return -EFAULT;
1053 	return snd_ctl_elem_add(file, &info, replace);
1054 }
1055 
1056 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1057 			       struct snd_ctl_elem_id __user *_id)
1058 {
1059 	struct snd_ctl_elem_id id;
1060 	int err;
1061 
1062 	if (copy_from_user(&id, _id, sizeof(id)))
1063 		return -EFAULT;
1064 	err = snd_ctl_remove_unlocked_id(file, &id);
1065 	if (! err) {
1066 		struct snd_card *card = file->card;
1067 		down_write(&card->controls_rwsem);
1068 		card->user_ctl_count--;
1069 		up_write(&card->controls_rwsem);
1070 	}
1071 	return err;
1072 }
1073 
1074 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1075 {
1076 	int subscribe;
1077 	if (get_user(subscribe, ptr))
1078 		return -EFAULT;
1079 	if (subscribe < 0) {
1080 		subscribe = file->subscribed;
1081 		if (put_user(subscribe, ptr))
1082 			return -EFAULT;
1083 		return 0;
1084 	}
1085 	if (subscribe) {
1086 		file->subscribed = 1;
1087 		return 0;
1088 	} else if (file->subscribed) {
1089 		snd_ctl_empty_read_queue(file);
1090 		file->subscribed = 0;
1091 	}
1092 	return 0;
1093 }
1094 
1095 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1096                              struct snd_ctl_tlv __user *_tlv,
1097                              int op_flag)
1098 {
1099 	struct snd_card *card = file->card;
1100 	struct snd_ctl_tlv tlv;
1101 	struct snd_kcontrol *kctl;
1102 	struct snd_kcontrol_volatile *vd;
1103 	unsigned int len;
1104 	int err = 0;
1105 
1106 	if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
1107 		return -EFAULT;
1108 	if (tlv.length < sizeof(unsigned int) * 3)
1109 		return -EINVAL;
1110 	down_read(&card->controls_rwsem);
1111 	kctl = snd_ctl_find_numid(card, tlv.numid);
1112 	if (kctl == NULL) {
1113 		err = -ENOENT;
1114 		goto __kctl_end;
1115 	}
1116 	if (kctl->tlv.p == NULL) {
1117 		err = -ENXIO;
1118 		goto __kctl_end;
1119 	}
1120 	vd = &kctl->vd[tlv.numid - kctl->id.numid];
1121 	if ((op_flag == 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||
1122 	    (op_flag > 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||
1123 	    (op_flag < 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0)) {
1124 	    	err = -ENXIO;
1125 	    	goto __kctl_end;
1126 	}
1127 	if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1128 		if (file && vd->owner != NULL && vd->owner != file) {
1129 			err = -EPERM;
1130 			goto __kctl_end;
1131 		}
1132 		err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv);
1133 		if (err > 0) {
1134 			up_read(&card->controls_rwsem);
1135 			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &kctl->id);
1136 			return 0;
1137 		}
1138 	} else {
1139 		if (op_flag) {
1140 			err = -ENXIO;
1141 			goto __kctl_end;
1142 		}
1143 		len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);
1144 		if (tlv.length < len) {
1145 			err = -ENOMEM;
1146 			goto __kctl_end;
1147 		}
1148 		if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))
1149 			err = -EFAULT;
1150 	}
1151       __kctl_end:
1152 	up_read(&card->controls_rwsem);
1153 	return err;
1154 }
1155 
1156 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1157 {
1158 	struct snd_ctl_file *ctl;
1159 	struct snd_card *card;
1160 	struct snd_kctl_ioctl *p;
1161 	void __user *argp = (void __user *)arg;
1162 	int __user *ip = argp;
1163 	int err;
1164 
1165 	ctl = file->private_data;
1166 	card = ctl->card;
1167 	if (snd_BUG_ON(!card))
1168 		return -ENXIO;
1169 	switch (cmd) {
1170 	case SNDRV_CTL_IOCTL_PVERSION:
1171 		return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1172 	case SNDRV_CTL_IOCTL_CARD_INFO:
1173 		return snd_ctl_card_info(card, ctl, cmd, argp);
1174 	case SNDRV_CTL_IOCTL_ELEM_LIST:
1175 		return snd_ctl_elem_list(card, argp);
1176 	case SNDRV_CTL_IOCTL_ELEM_INFO:
1177 		return snd_ctl_elem_info_user(ctl, argp);
1178 	case SNDRV_CTL_IOCTL_ELEM_READ:
1179 		return snd_ctl_elem_read_user(card, argp);
1180 	case SNDRV_CTL_IOCTL_ELEM_WRITE:
1181 		return snd_ctl_elem_write_user(ctl, argp);
1182 	case SNDRV_CTL_IOCTL_ELEM_LOCK:
1183 		return snd_ctl_elem_lock(ctl, argp);
1184 	case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1185 		return snd_ctl_elem_unlock(ctl, argp);
1186 	case SNDRV_CTL_IOCTL_ELEM_ADD:
1187 		return snd_ctl_elem_add_user(ctl, argp, 0);
1188 	case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1189 		return snd_ctl_elem_add_user(ctl, argp, 1);
1190 	case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1191 		return snd_ctl_elem_remove(ctl, argp);
1192 	case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1193 		return snd_ctl_subscribe_events(ctl, ip);
1194 	case SNDRV_CTL_IOCTL_TLV_READ:
1195 		return snd_ctl_tlv_ioctl(ctl, argp, 0);
1196 	case SNDRV_CTL_IOCTL_TLV_WRITE:
1197 		return snd_ctl_tlv_ioctl(ctl, argp, 1);
1198 	case SNDRV_CTL_IOCTL_TLV_COMMAND:
1199 		return snd_ctl_tlv_ioctl(ctl, argp, -1);
1200 	case SNDRV_CTL_IOCTL_POWER:
1201 		return -ENOPROTOOPT;
1202 	case SNDRV_CTL_IOCTL_POWER_STATE:
1203 #ifdef CONFIG_PM
1204 		return put_user(card->power_state, ip) ? -EFAULT : 0;
1205 #else
1206 		return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1207 #endif
1208 	}
1209 	down_read(&snd_ioctl_rwsem);
1210 	list_for_each_entry(p, &snd_control_ioctls, list) {
1211 		err = p->fioctl(card, ctl, cmd, arg);
1212 		if (err != -ENOIOCTLCMD) {
1213 			up_read(&snd_ioctl_rwsem);
1214 			return err;
1215 		}
1216 	}
1217 	up_read(&snd_ioctl_rwsem);
1218 	snd_printdd("unknown ioctl = 0x%x\n", cmd);
1219 	return -ENOTTY;
1220 }
1221 
1222 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1223 			    size_t count, loff_t * offset)
1224 {
1225 	struct snd_ctl_file *ctl;
1226 	int err = 0;
1227 	ssize_t result = 0;
1228 
1229 	ctl = file->private_data;
1230 	if (snd_BUG_ON(!ctl || !ctl->card))
1231 		return -ENXIO;
1232 	if (!ctl->subscribed)
1233 		return -EBADFD;
1234 	if (count < sizeof(struct snd_ctl_event))
1235 		return -EINVAL;
1236 	spin_lock_irq(&ctl->read_lock);
1237 	while (count >= sizeof(struct snd_ctl_event)) {
1238 		struct snd_ctl_event ev;
1239 		struct snd_kctl_event *kev;
1240 		while (list_empty(&ctl->events)) {
1241 			wait_queue_t wait;
1242 			if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1243 				err = -EAGAIN;
1244 				goto __end_lock;
1245 			}
1246 			init_waitqueue_entry(&wait, current);
1247 			add_wait_queue(&ctl->change_sleep, &wait);
1248 			set_current_state(TASK_INTERRUPTIBLE);
1249 			spin_unlock_irq(&ctl->read_lock);
1250 			schedule();
1251 			remove_wait_queue(&ctl->change_sleep, &wait);
1252 			if (signal_pending(current))
1253 				return -ERESTARTSYS;
1254 			spin_lock_irq(&ctl->read_lock);
1255 		}
1256 		kev = snd_kctl_event(ctl->events.next);
1257 		ev.type = SNDRV_CTL_EVENT_ELEM;
1258 		ev.data.elem.mask = kev->mask;
1259 		ev.data.elem.id = kev->id;
1260 		list_del(&kev->list);
1261 		spin_unlock_irq(&ctl->read_lock);
1262 		kfree(kev);
1263 		if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1264 			err = -EFAULT;
1265 			goto __end;
1266 		}
1267 		spin_lock_irq(&ctl->read_lock);
1268 		buffer += sizeof(struct snd_ctl_event);
1269 		count -= sizeof(struct snd_ctl_event);
1270 		result += sizeof(struct snd_ctl_event);
1271 	}
1272       __end_lock:
1273 	spin_unlock_irq(&ctl->read_lock);
1274       __end:
1275       	return result > 0 ? result : err;
1276 }
1277 
1278 static unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
1279 {
1280 	unsigned int mask;
1281 	struct snd_ctl_file *ctl;
1282 
1283 	ctl = file->private_data;
1284 	if (!ctl->subscribed)
1285 		return 0;
1286 	poll_wait(file, &ctl->change_sleep, wait);
1287 
1288 	mask = 0;
1289 	if (!list_empty(&ctl->events))
1290 		mask |= POLLIN | POLLRDNORM;
1291 
1292 	return mask;
1293 }
1294 
1295 /*
1296  * register the device-specific control-ioctls.
1297  * called from each device manager like pcm.c, hwdep.c, etc.
1298  */
1299 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1300 {
1301 	struct snd_kctl_ioctl *pn;
1302 
1303 	pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1304 	if (pn == NULL)
1305 		return -ENOMEM;
1306 	pn->fioctl = fcn;
1307 	down_write(&snd_ioctl_rwsem);
1308 	list_add_tail(&pn->list, lists);
1309 	up_write(&snd_ioctl_rwsem);
1310 	return 0;
1311 }
1312 
1313 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1314 {
1315 	return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1316 }
1317 
1318 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1319 
1320 #ifdef CONFIG_COMPAT
1321 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1322 {
1323 	return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1324 }
1325 
1326 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1327 #endif
1328 
1329 /*
1330  * de-register the device-specific control-ioctls.
1331  */
1332 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1333 				     struct list_head *lists)
1334 {
1335 	struct snd_kctl_ioctl *p;
1336 
1337 	if (snd_BUG_ON(!fcn))
1338 		return -EINVAL;
1339 	down_write(&snd_ioctl_rwsem);
1340 	list_for_each_entry(p, lists, list) {
1341 		if (p->fioctl == fcn) {
1342 			list_del(&p->list);
1343 			up_write(&snd_ioctl_rwsem);
1344 			kfree(p);
1345 			return 0;
1346 		}
1347 	}
1348 	up_write(&snd_ioctl_rwsem);
1349 	snd_BUG();
1350 	return -EINVAL;
1351 }
1352 
1353 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1354 {
1355 	return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1356 }
1357 
1358 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1359 
1360 #ifdef CONFIG_COMPAT
1361 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1362 {
1363 	return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1364 }
1365 
1366 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1367 #endif
1368 
1369 static int snd_ctl_fasync(int fd, struct file * file, int on)
1370 {
1371 	struct snd_ctl_file *ctl;
1372 	int err;
1373 	ctl = file->private_data;
1374 	err = fasync_helper(fd, file, on, &ctl->fasync);
1375 	if (err < 0)
1376 		return err;
1377 	return 0;
1378 }
1379 
1380 /*
1381  * ioctl32 compat
1382  */
1383 #ifdef CONFIG_COMPAT
1384 #include "control_compat.c"
1385 #else
1386 #define snd_ctl_ioctl_compat	NULL
1387 #endif
1388 
1389 /*
1390  *  INIT PART
1391  */
1392 
1393 static const struct file_operations snd_ctl_f_ops =
1394 {
1395 	.owner =	THIS_MODULE,
1396 	.read =		snd_ctl_read,
1397 	.open =		snd_ctl_open,
1398 	.release =	snd_ctl_release,
1399 	.poll =		snd_ctl_poll,
1400 	.unlocked_ioctl =	snd_ctl_ioctl,
1401 	.compat_ioctl =	snd_ctl_ioctl_compat,
1402 	.fasync =	snd_ctl_fasync,
1403 };
1404 
1405 /*
1406  * registration of the control device
1407  */
1408 static int snd_ctl_dev_register(struct snd_device *device)
1409 {
1410 	struct snd_card *card = device->device_data;
1411 	int err, cardnum;
1412 	char name[16];
1413 
1414 	if (snd_BUG_ON(!card))
1415 		return -ENXIO;
1416 	cardnum = card->number;
1417 	if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
1418 		return -ENXIO;
1419 	sprintf(name, "controlC%i", cardnum);
1420 	if ((err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
1421 				       &snd_ctl_f_ops, card, name)) < 0)
1422 		return err;
1423 	return 0;
1424 }
1425 
1426 /*
1427  * disconnection of the control device
1428  */
1429 static int snd_ctl_dev_disconnect(struct snd_device *device)
1430 {
1431 	struct snd_card *card = device->device_data;
1432 	struct snd_ctl_file *ctl;
1433 	int err, cardnum;
1434 
1435 	if (snd_BUG_ON(!card))
1436 		return -ENXIO;
1437 	cardnum = card->number;
1438 	if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
1439 		return -ENXIO;
1440 
1441 	read_lock(&card->ctl_files_rwlock);
1442 	list_for_each_entry(ctl, &card->ctl_files, list) {
1443 		wake_up(&ctl->change_sleep);
1444 		kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1445 	}
1446 	read_unlock(&card->ctl_files_rwlock);
1447 
1448 	if ((err = snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL,
1449 					 card, -1)) < 0)
1450 		return err;
1451 	return 0;
1452 }
1453 
1454 /*
1455  * free all controls
1456  */
1457 static int snd_ctl_dev_free(struct snd_device *device)
1458 {
1459 	struct snd_card *card = device->device_data;
1460 	struct snd_kcontrol *control;
1461 
1462 	down_write(&card->controls_rwsem);
1463 	while (!list_empty(&card->controls)) {
1464 		control = snd_kcontrol(card->controls.next);
1465 		snd_ctl_remove(card, control);
1466 	}
1467 	up_write(&card->controls_rwsem);
1468 	return 0;
1469 }
1470 
1471 /*
1472  * create control core:
1473  * called from init.c
1474  */
1475 int snd_ctl_create(struct snd_card *card)
1476 {
1477 	static struct snd_device_ops ops = {
1478 		.dev_free = snd_ctl_dev_free,
1479 		.dev_register =	snd_ctl_dev_register,
1480 		.dev_disconnect = snd_ctl_dev_disconnect,
1481 	};
1482 
1483 	if (snd_BUG_ON(!card))
1484 		return -ENXIO;
1485 	return snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1486 }
1487 
1488 /*
1489  * Frequently used control callbacks
1490  */
1491 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
1492 			      struct snd_ctl_elem_info *uinfo)
1493 {
1494 	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1495 	uinfo->count = 1;
1496 	uinfo->value.integer.min = 0;
1497 	uinfo->value.integer.max = 1;
1498 	return 0;
1499 }
1500 
1501 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
1502 
1503 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
1504 				struct snd_ctl_elem_info *uinfo)
1505 {
1506 	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1507 	uinfo->count = 2;
1508 	uinfo->value.integer.min = 0;
1509 	uinfo->value.integer.max = 1;
1510 	return 0;
1511 }
1512 
1513 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
1514