[ALSA] Decentralize PM control
[linux-2.6.git] / sound / core / control.c
1 /*
2  *  Routines for driver control interface
3  *  Copyright (c) by Jaroslav Kysela <perex@suse.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 <sound/driver.h>
23 #include <linux/threads.h>
24 #include <linux/interrupt.h>
25 #include <linux/smp_lock.h>
26 #include <linux/slab.h>
27 #include <linux/vmalloc.h>
28 #include <linux/time.h>
29 #include <sound/core.h>
30 #include <sound/minors.h>
31 #include <sound/info.h>
32 #include <sound/control.h>
33
34 /* max number of user-defined controls */
35 #define MAX_USER_CONTROLS       32
36
37 struct snd_kctl_ioctl {
38         struct list_head list;          /* list of all ioctls */
39         snd_kctl_ioctl_func_t fioctl;
40 };
41
42 static DECLARE_RWSEM(snd_ioctl_rwsem);
43 static LIST_HEAD(snd_control_ioctls);
44 #ifdef CONFIG_COMPAT
45 static LIST_HEAD(snd_control_compat_ioctls);
46 #endif
47
48 static int snd_ctl_open(struct inode *inode, struct file *file)
49 {
50         int cardnum = SNDRV_MINOR_CARD(iminor(inode));
51         unsigned long flags;
52         struct snd_card *card;
53         struct snd_ctl_file *ctl;
54         int err;
55
56         card = snd_cards[cardnum];
57         if (!card) {
58                 err = -ENODEV;
59                 goto __error1;
60         }
61         err = snd_card_file_add(card, file);
62         if (err < 0) {
63                 err = -ENODEV;
64                 goto __error1;
65         }
66         if (!try_module_get(card->module)) {
67                 err = -EFAULT;
68                 goto __error2;
69         }
70         ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
71         if (ctl == NULL) {
72                 err = -ENOMEM;
73                 goto __error;
74         }
75         INIT_LIST_HEAD(&ctl->events);
76         init_waitqueue_head(&ctl->change_sleep);
77         spin_lock_init(&ctl->read_lock);
78         ctl->card = card;
79         ctl->pid = current->pid;
80         file->private_data = ctl;
81         write_lock_irqsave(&card->ctl_files_rwlock, flags);
82         list_add_tail(&ctl->list, &card->ctl_files);
83         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
84         return 0;
85
86       __error:
87         module_put(card->module);
88       __error2:
89         snd_card_file_remove(card, file);
90       __error1:
91         return err;
92 }
93
94 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
95 {
96         struct snd_kctl_event *cread;
97         
98         spin_lock(&ctl->read_lock);
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(&ctl->read_lock);
105 }
106
107 static int snd_ctl_release(struct inode *inode, struct file *file)
108 {
109         unsigned long flags;
110         struct list_head *list;
111         struct snd_card *card;
112         struct snd_ctl_file *ctl;
113         struct snd_kcontrol *control;
114         unsigned int idx;
115
116         ctl = file->private_data;
117         fasync_helper(-1, file, 0, &ctl->fasync);
118         file->private_data = NULL;
119         card = ctl->card;
120         write_lock_irqsave(&card->ctl_files_rwlock, flags);
121         list_del(&ctl->list);
122         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
123         down_write(&card->controls_rwsem);
124         list_for_each(list, &card->controls) {
125                 control = snd_kcontrol(list);
126                 for (idx = 0; idx < control->count; idx++)
127                         if (control->vd[idx].owner == ctl)
128                                 control->vd[idx].owner = NULL;
129         }
130         up_write(&card->controls_rwsem);
131         snd_ctl_empty_read_queue(ctl);
132         kfree(ctl);
133         module_put(card->module);
134         snd_card_file_remove(card, file);
135         return 0;
136 }
137
138 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
139                     struct snd_ctl_elem_id *id)
140 {
141         unsigned long flags;
142         struct list_head *flist;
143         struct snd_ctl_file *ctl;
144         struct snd_kctl_event *ev;
145         
146         snd_assert(card != NULL && id != NULL, return);
147         read_lock(&card->ctl_files_rwlock);
148 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
149         card->mixer_oss_change_count++;
150 #endif
151         list_for_each(flist, &card->ctl_files) {
152                 struct list_head *elist;
153                 ctl = snd_ctl_file(flist);
154                 if (!ctl->subscribed)
155                         continue;
156                 spin_lock_irqsave(&ctl->read_lock, flags);
157                 list_for_each(elist, &ctl->events) {
158                         ev = snd_kctl_event(elist);
159                         if (ev->id.numid == id->numid) {
160                                 ev->mask |= mask;
161                                 goto _found;
162                         }
163                 }
164                 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
165                 if (ev) {
166                         ev->id = *id;
167                         ev->mask = mask;
168                         list_add_tail(&ev->list, &ctl->events);
169                 } else {
170                         snd_printk(KERN_ERR "No memory available to allocate event\n");
171                 }
172         _found:
173                 wake_up(&ctl->change_sleep);
174                 spin_unlock_irqrestore(&ctl->read_lock, flags);
175                 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
176         }
177         read_unlock(&card->ctl_files_rwlock);
178 }
179
180 /**
181  * snd_ctl_new - create a control instance from the template
182  * @control: the control template
183  * @access: the default control access
184  *
185  * Allocates a new struct snd_kcontrol instance and copies the given template 
186  * to the new instance. It does not copy volatile data (access).
187  *
188  * Returns the pointer of the new instance, or NULL on failure.
189  */
190 struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control, unsigned int access)
191 {
192         struct snd_kcontrol *kctl;
193         unsigned int idx;
194         
195         snd_assert(control != NULL, return NULL);
196         snd_assert(control->count > 0, return NULL);
197         kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL);
198         if (kctl == NULL)
199                 return NULL;
200         *kctl = *control;
201         for (idx = 0; idx < kctl->count; idx++)
202                 kctl->vd[idx].access = access;
203         return kctl;
204 }
205
206 /**
207  * snd_ctl_new1 - create a control instance from the template
208  * @ncontrol: the initialization record
209  * @private_data: the private data to set
210  *
211  * Allocates a new struct snd_kcontrol instance and initialize from the given 
212  * template.  When the access field of ncontrol is 0, it's assumed as
213  * READWRITE access. When the count field is 0, it's assumes as one.
214  *
215  * Returns the pointer of the newly generated instance, or NULL on failure.
216  */
217 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
218                                   void *private_data)
219 {
220         struct snd_kcontrol kctl;
221         unsigned int access;
222         
223         snd_assert(ncontrol != NULL, return NULL);
224         snd_assert(ncontrol->info != NULL, return NULL);
225         memset(&kctl, 0, sizeof(kctl));
226         kctl.id.iface = ncontrol->iface;
227         kctl.id.device = ncontrol->device;
228         kctl.id.subdevice = ncontrol->subdevice;
229         if (ncontrol->name)
230                 strlcpy(kctl.id.name, ncontrol->name, sizeof(kctl.id.name));
231         kctl.id.index = ncontrol->index;
232         kctl.count = ncontrol->count ? ncontrol->count : 1;
233         access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
234                  (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|SNDRV_CTL_ELEM_ACCESS_INACTIVE|
235                                       SNDRV_CTL_ELEM_ACCESS_DINDIRECT|SNDRV_CTL_ELEM_ACCESS_INDIRECT));
236         kctl.info = ncontrol->info;
237         kctl.get = ncontrol->get;
238         kctl.put = ncontrol->put;
239         kctl.private_value = ncontrol->private_value;
240         kctl.private_data = private_data;
241         return snd_ctl_new(&kctl, access);
242 }
243
244 /**
245  * snd_ctl_free_one - release the control instance
246  * @kcontrol: the control instance
247  *
248  * Releases the control instance created via snd_ctl_new()
249  * or snd_ctl_new1().
250  * Don't call this after the control was added to the card.
251  */
252 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
253 {
254         if (kcontrol) {
255                 if (kcontrol->private_free)
256                         kcontrol->private_free(kcontrol);
257                 kfree(kcontrol);
258         }
259 }
260
261 static unsigned int snd_ctl_hole_check(struct snd_card *card,
262                                        unsigned int count)
263 {
264         struct list_head *list;
265         struct snd_kcontrol *kctl;
266
267         list_for_each(list, &card->controls) {
268                 kctl = snd_kcontrol(list);
269                 if ((kctl->id.numid <= card->last_numid &&
270                      kctl->id.numid + kctl->count > card->last_numid) ||
271                     (kctl->id.numid <= card->last_numid + count - 1 &&
272                      kctl->id.numid + kctl->count > card->last_numid + count - 1))
273                         return card->last_numid = kctl->id.numid + kctl->count - 1;
274         }
275         return card->last_numid;
276 }
277
278 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
279 {
280         unsigned int last_numid, iter = 100000;
281
282         last_numid = card->last_numid;
283         while (last_numid != snd_ctl_hole_check(card, count)) {
284                 if (--iter == 0) {
285                         /* this situation is very unlikely */
286                         snd_printk(KERN_ERR "unable to allocate new control numid\n");
287                         return -ENOMEM;
288                 }
289                 last_numid = card->last_numid;
290         }
291         return 0;
292 }
293
294 /**
295  * snd_ctl_add - add the control instance to the card
296  * @card: the card instance
297  * @kcontrol: the control instance to add
298  *
299  * Adds the control instance created via snd_ctl_new() or
300  * snd_ctl_new1() to the given card. Assigns also an unique
301  * numid used for fast search.
302  *
303  * Returns zero if successful, or a negative error code on failure.
304  *
305  * It frees automatically the control which cannot be added.
306  */
307 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
308 {
309         struct snd_ctl_elem_id id;
310         unsigned int idx;
311
312         snd_assert(card != NULL && kcontrol != NULL, return -EINVAL);
313         snd_assert(kcontrol->info != NULL, return -EINVAL);
314         id = kcontrol->id;
315         down_write(&card->controls_rwsem);
316         if (snd_ctl_find_id(card, &id)) {
317                 up_write(&card->controls_rwsem);
318                 snd_ctl_free_one(kcontrol);
319                 snd_printd(KERN_ERR "control %i:%i:%i:%s:%i is already present\n",
320                                         id.iface,
321                                         id.device,
322                                         id.subdevice,
323                                         id.name,
324                                         id.index);
325                 return -EBUSY;
326         }
327         if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
328                 up_write(&card->controls_rwsem);
329                 snd_ctl_free_one(kcontrol);
330                 return -ENOMEM;
331         }
332         list_add_tail(&kcontrol->list, &card->controls);
333         card->controls_count += kcontrol->count;
334         kcontrol->id.numid = card->last_numid + 1;
335         card->last_numid += kcontrol->count;
336         up_write(&card->controls_rwsem);
337         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
338                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
339         return 0;
340 }
341
342 /**
343  * snd_ctl_remove - remove the control from the card and release it
344  * @card: the card instance
345  * @kcontrol: the control instance to remove
346  *
347  * Removes the control from the card and then releases the instance.
348  * You don't need to call snd_ctl_free_one(). You must be in
349  * the write lock - down_write(&card->controls_rwsem).
350  * 
351  * Returns 0 if successful, or a negative error code on failure.
352  */
353 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
354 {
355         struct snd_ctl_elem_id id;
356         unsigned int idx;
357
358         snd_assert(card != NULL && kcontrol != NULL, return -EINVAL);
359         list_del(&kcontrol->list);
360         card->controls_count -= kcontrol->count;
361         id = kcontrol->id;
362         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
363                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
364         snd_ctl_free_one(kcontrol);
365         return 0;
366 }
367
368 /**
369  * snd_ctl_remove_id - remove the control of the given id and release it
370  * @card: the card instance
371  * @id: the control id to remove
372  *
373  * Finds the control instance with the given id, removes it from the
374  * card list and releases it.
375  * 
376  * Returns 0 if successful, or a negative error code on failure.
377  */
378 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
379 {
380         struct snd_kcontrol *kctl;
381         int ret;
382
383         down_write(&card->controls_rwsem);
384         kctl = snd_ctl_find_id(card, id);
385         if (kctl == NULL) {
386                 up_write(&card->controls_rwsem);
387                 return -ENOENT;
388         }
389         ret = snd_ctl_remove(card, kctl);
390         up_write(&card->controls_rwsem);
391         return ret;
392 }
393
394 /**
395  * snd_ctl_remove_unlocked_id - remove the unlocked control of the given id and release it
396  * @file: active control handle
397  * @id: the control id to remove
398  *
399  * Finds the control instance with the given id, removes it from the
400  * card list and releases it.
401  * 
402  * Returns 0 if successful, or a negative error code on failure.
403  */
404 static int snd_ctl_remove_unlocked_id(struct snd_ctl_file * file,
405                                       struct snd_ctl_elem_id *id)
406 {
407         struct snd_card *card = file->card;
408         struct snd_kcontrol *kctl;
409         int idx, ret;
410
411         down_write(&card->controls_rwsem);
412         kctl = snd_ctl_find_id(card, id);
413         if (kctl == NULL) {
414                 up_write(&card->controls_rwsem);
415                 return -ENOENT;
416         }
417         for (idx = 0; idx < kctl->count; idx++)
418                 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
419                         up_write(&card->controls_rwsem);
420                         return -EBUSY;
421                 }
422         ret = snd_ctl_remove(card, kctl);
423         up_write(&card->controls_rwsem);
424         return ret;
425 }
426
427 /**
428  * snd_ctl_rename_id - replace the id of a control on the card
429  * @card: the card instance
430  * @src_id: the old id
431  * @dst_id: the new id
432  *
433  * Finds the control with the old id from the card, and replaces the
434  * id with the new one.
435  *
436  * Returns zero if successful, or a negative error code on failure.
437  */
438 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
439                       struct snd_ctl_elem_id *dst_id)
440 {
441         struct snd_kcontrol *kctl;
442
443         down_write(&card->controls_rwsem);
444         kctl = snd_ctl_find_id(card, src_id);
445         if (kctl == NULL) {
446                 up_write(&card->controls_rwsem);
447                 return -ENOENT;
448         }
449         kctl->id = *dst_id;
450         kctl->id.numid = card->last_numid + 1;
451         card->last_numid += kctl->count;
452         up_write(&card->controls_rwsem);
453         return 0;
454 }
455
456 /**
457  * snd_ctl_find_numid - find the control instance with the given number-id
458  * @card: the card instance
459  * @numid: the number-id to search
460  *
461  * Finds the control instance with the given number-id from the card.
462  *
463  * Returns the pointer of the instance if found, or NULL if not.
464  *
465  * The caller must down card->controls_rwsem before calling this function
466  * (if the race condition can happen).
467  */
468 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
469 {
470         struct list_head *list;
471         struct snd_kcontrol *kctl;
472
473         snd_assert(card != NULL && numid != 0, return NULL);
474         list_for_each(list, &card->controls) {
475                 kctl = snd_kcontrol(list);
476                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
477                         return kctl;
478         }
479         return NULL;
480 }
481
482 /**
483  * snd_ctl_find_id - find the control instance with the given id
484  * @card: the card instance
485  * @id: the id to search
486  *
487  * Finds the control instance with the given id from the card.
488  *
489  * Returns the pointer of the instance if found, or NULL if not.
490  *
491  * The caller must down card->controls_rwsem before calling this function
492  * (if the race condition can happen).
493  */
494 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
495                                      struct snd_ctl_elem_id *id)
496 {
497         struct list_head *list;
498         struct snd_kcontrol *kctl;
499
500         snd_assert(card != NULL && id != NULL, return NULL);
501         if (id->numid != 0)
502                 return snd_ctl_find_numid(card, id->numid);
503         list_for_each(list, &card->controls) {
504                 kctl = snd_kcontrol(list);
505                 if (kctl->id.iface != id->iface)
506                         continue;
507                 if (kctl->id.device != id->device)
508                         continue;
509                 if (kctl->id.subdevice != id->subdevice)
510                         continue;
511                 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
512                         continue;
513                 if (kctl->id.index > id->index)
514                         continue;
515                 if (kctl->id.index + kctl->count <= id->index)
516                         continue;
517                 return kctl;
518         }
519         return NULL;
520 }
521
522 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
523                              unsigned int cmd, void __user *arg)
524 {
525         struct snd_ctl_card_info *info;
526
527         info = kzalloc(sizeof(*info), GFP_KERNEL);
528         if (! info)
529                 return -ENOMEM;
530         down_read(&snd_ioctl_rwsem);
531         info->card = card->number;
532         strlcpy(info->id, card->id, sizeof(info->id));
533         strlcpy(info->driver, card->driver, sizeof(info->driver));
534         strlcpy(info->name, card->shortname, sizeof(info->name));
535         strlcpy(info->longname, card->longname, sizeof(info->longname));
536         strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
537         strlcpy(info->components, card->components, sizeof(info->components));
538         up_read(&snd_ioctl_rwsem);
539         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
540                 kfree(info);
541                 return -EFAULT;
542         }
543         kfree(info);
544         return 0;
545 }
546
547 static int snd_ctl_elem_list(struct snd_card *card,
548                              struct snd_ctl_elem_list __user *_list)
549 {
550         struct list_head *plist;
551         struct snd_ctl_elem_list list;
552         struct snd_kcontrol *kctl;
553         struct snd_ctl_elem_id *dst, *id;
554         unsigned int offset, space, first, jidx;
555         
556         if (copy_from_user(&list, _list, sizeof(list)))
557                 return -EFAULT;
558         offset = list.offset;
559         space = list.space;
560         first = 0;
561         /* try limit maximum space */
562         if (space > 16384)
563                 return -ENOMEM;
564         if (space > 0) {
565                 /* allocate temporary buffer for atomic operation */
566                 dst = vmalloc(space * sizeof(struct snd_ctl_elem_id));
567                 if (dst == NULL)
568                         return -ENOMEM;
569                 down_read(&card->controls_rwsem);
570                 list.count = card->controls_count;
571                 plist = card->controls.next;
572                 while (plist != &card->controls) {
573                         if (offset == 0)
574                                 break;
575                         kctl = snd_kcontrol(plist);
576                         if (offset < kctl->count)
577                                 break;
578                         offset -= kctl->count;
579                         plist = plist->next;
580                 }
581                 list.used = 0;
582                 id = dst;
583                 while (space > 0 && plist != &card->controls) {
584                         kctl = snd_kcontrol(plist);
585                         for (jidx = offset; space > 0 && jidx < kctl->count; jidx++) {
586                                 snd_ctl_build_ioff(id, kctl, jidx);
587                                 id++;
588                                 space--;
589                                 list.used++;
590                         }
591                         plist = plist->next;
592                         offset = 0;
593                 }
594                 up_read(&card->controls_rwsem);
595                 if (list.used > 0 &&
596                     copy_to_user(list.pids, dst,
597                                  list.used * sizeof(struct snd_ctl_elem_id))) {
598                         vfree(dst);
599                         return -EFAULT;
600                 }
601                 vfree(dst);
602         } else {
603                 down_read(&card->controls_rwsem);
604                 list.count = card->controls_count;
605                 up_read(&card->controls_rwsem);
606         }
607         if (copy_to_user(_list, &list, sizeof(list)))
608                 return -EFAULT;
609         return 0;
610 }
611
612 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
613                              struct snd_ctl_elem_info *info)
614 {
615         struct snd_card *card = ctl->card;
616         struct snd_kcontrol *kctl;
617         struct snd_kcontrol_volatile *vd;
618         unsigned int index_offset;
619         int result;
620         
621         down_read(&card->controls_rwsem);
622         kctl = snd_ctl_find_id(card, &info->id);
623         if (kctl == NULL) {
624                 up_read(&card->controls_rwsem);
625                 return -ENOENT;
626         }
627 #ifdef CONFIG_SND_DEBUG
628         info->access = 0;
629 #endif
630         result = kctl->info(kctl, info);
631         if (result >= 0) {
632                 snd_assert(info->access == 0, );
633                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
634                 vd = &kctl->vd[index_offset];
635                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
636                 info->access = vd->access;
637                 if (vd->owner) {
638                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
639                         if (vd->owner == ctl)
640                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
641                         info->owner = vd->owner_pid;
642                 } else {
643                         info->owner = -1;
644                 }
645         }
646         up_read(&card->controls_rwsem);
647         return result;
648 }
649
650 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
651                                   struct snd_ctl_elem_info __user *_info)
652 {
653         struct snd_ctl_elem_info info;
654         int result;
655
656         if (copy_from_user(&info, _info, sizeof(info)))
657                 return -EFAULT;
658         result = snd_ctl_elem_info(ctl, &info);
659         if (result >= 0)
660                 if (copy_to_user(_info, &info, sizeof(info)))
661                         return -EFAULT;
662         return result;
663 }
664
665 int snd_ctl_elem_read(struct snd_card *card, struct snd_ctl_elem_value *control)
666 {
667         struct snd_kcontrol *kctl;
668         struct snd_kcontrol_volatile *vd;
669         unsigned int index_offset;
670         int result, indirect;
671
672         down_read(&card->controls_rwsem);
673         kctl = snd_ctl_find_id(card, &control->id);
674         if (kctl == NULL) {
675                 result = -ENOENT;
676         } else {
677                 index_offset = snd_ctl_get_ioff(kctl, &control->id);
678                 vd = &kctl->vd[index_offset];
679                 indirect = vd->access & SNDRV_CTL_ELEM_ACCESS_INDIRECT ? 1 : 0;
680                 if (control->indirect != indirect) {
681                         result = -EACCES;
682                 } else {
683                         if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) && kctl->get != NULL) {
684                                 snd_ctl_build_ioff(&control->id, kctl, index_offset);
685                                 result = kctl->get(kctl, control);
686                         } else {
687                                 result = -EPERM;
688                         }
689                 }
690         }
691         up_read(&card->controls_rwsem);
692         return result;
693 }
694
695 static int snd_ctl_elem_read_user(struct snd_card *card,
696                                   struct snd_ctl_elem_value __user *_control)
697 {
698         struct snd_ctl_elem_value *control;
699         int result;
700         
701         control = kmalloc(sizeof(*control), GFP_KERNEL);
702         if (control == NULL)
703                 return -ENOMEM; 
704         if (copy_from_user(control, _control, sizeof(*control))) {
705                 kfree(control);
706                 return -EFAULT;
707         }
708         result = snd_ctl_elem_read(card, control);
709         if (result >= 0)
710                 if (copy_to_user(_control, control, sizeof(*control)))
711                         result = -EFAULT;
712         kfree(control);
713         return result;
714 }
715
716 int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
717                        struct snd_ctl_elem_value *control)
718 {
719         struct snd_kcontrol *kctl;
720         struct snd_kcontrol_volatile *vd;
721         unsigned int index_offset;
722         int result, indirect;
723
724         down_read(&card->controls_rwsem);
725         kctl = snd_ctl_find_id(card, &control->id);
726         if (kctl == NULL) {
727                 result = -ENOENT;
728         } else {
729                 index_offset = snd_ctl_get_ioff(kctl, &control->id);
730                 vd = &kctl->vd[index_offset];
731                 indirect = vd->access & SNDRV_CTL_ELEM_ACCESS_INDIRECT ? 1 : 0;
732                 if (control->indirect != indirect) {
733                         result = -EACCES;
734                 } else {
735                         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
736                             kctl->put == NULL ||
737                             (file && vd->owner != NULL && vd->owner != file)) {
738                                 result = -EPERM;
739                         } else {
740                                 snd_ctl_build_ioff(&control->id, kctl, index_offset);
741                                 result = kctl->put(kctl, control);
742                         }
743                         if (result > 0) {
744                                 up_read(&card->controls_rwsem);
745                                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &control->id);
746                                 return 0;
747                         }
748                 }
749         }
750         up_read(&card->controls_rwsem);
751         return result;
752 }
753
754 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
755                                    struct snd_ctl_elem_value __user *_control)
756 {
757         struct snd_ctl_elem_value *control;
758         int result;
759
760         control = kmalloc(sizeof(*control), GFP_KERNEL);
761         if (control == NULL)
762                 return -ENOMEM; 
763         if (copy_from_user(control, _control, sizeof(*control))) {
764                 kfree(control);
765                 return -EFAULT;
766         }
767         result = snd_ctl_elem_write(file->card, file, control);
768         if (result >= 0)
769                 if (copy_to_user(_control, control, sizeof(*control)))
770                         result = -EFAULT;
771         kfree(control);
772         return result;
773 }
774
775 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
776                              struct snd_ctl_elem_id __user *_id)
777 {
778         struct snd_card *card = file->card;
779         struct snd_ctl_elem_id id;
780         struct snd_kcontrol *kctl;
781         struct snd_kcontrol_volatile *vd;
782         int result;
783         
784         if (copy_from_user(&id, _id, sizeof(id)))
785                 return -EFAULT;
786         down_write(&card->controls_rwsem);
787         kctl = snd_ctl_find_id(card, &id);
788         if (kctl == NULL) {
789                 result = -ENOENT;
790         } else {
791                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
792                 if (vd->owner != NULL)
793                         result = -EBUSY;
794                 else {
795                         vd->owner = file;
796                         vd->owner_pid = current->pid;
797                         result = 0;
798                 }
799         }
800         up_write(&card->controls_rwsem);
801         return result;
802 }
803
804 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
805                                struct snd_ctl_elem_id __user *_id)
806 {
807         struct snd_card *card = file->card;
808         struct snd_ctl_elem_id id;
809         struct snd_kcontrol *kctl;
810         struct snd_kcontrol_volatile *vd;
811         int result;
812         
813         if (copy_from_user(&id, _id, sizeof(id)))
814                 return -EFAULT;
815         down_write(&card->controls_rwsem);
816         kctl = snd_ctl_find_id(card, &id);
817         if (kctl == NULL) {
818                 result = -ENOENT;
819         } else {
820                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
821                 if (vd->owner == NULL)
822                         result = -EINVAL;
823                 else if (vd->owner != file)
824                         result = -EPERM;
825                 else {
826                         vd->owner = NULL;
827                         vd->owner_pid = 0;
828                         result = 0;
829                 }
830         }
831         up_write(&card->controls_rwsem);
832         return result;
833 }
834
835 struct user_element {
836         struct snd_ctl_elem_info info;
837         void *elem_data;                /* element data */
838         unsigned long elem_data_size;   /* size of element data in bytes */
839         void *priv_data;                /* private data (like strings for enumerated type) */
840         unsigned long priv_data_size;   /* size of private data in bytes */
841 };
842
843 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
844                                   struct snd_ctl_elem_info *uinfo)
845 {
846         struct user_element *ue = kcontrol->private_data;
847
848         *uinfo = ue->info;
849         return 0;
850 }
851
852 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
853                                  struct snd_ctl_elem_value *ucontrol)
854 {
855         struct user_element *ue = kcontrol->private_data;
856
857         memcpy(&ucontrol->value, ue->elem_data, ue->elem_data_size);
858         return 0;
859 }
860
861 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
862                                  struct snd_ctl_elem_value *ucontrol)
863 {
864         int change;
865         struct user_element *ue = kcontrol->private_data;
866         
867         change = memcmp(&ucontrol->value, ue->elem_data, ue->elem_data_size) != 0;
868         if (change)
869                 memcpy(ue->elem_data, &ucontrol->value, ue->elem_data_size);
870         return change;
871 }
872
873 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
874 {
875         kfree(kcontrol->private_data);
876 }
877
878 static int snd_ctl_elem_add(struct snd_ctl_file *file,
879                             struct snd_ctl_elem_info *info, int replace)
880 {
881         struct snd_card *card = file->card;
882         struct snd_kcontrol kctl, *_kctl;
883         unsigned int access;
884         long private_size;
885         struct user_element *ue;
886         int idx, err;
887         
888         if (card->user_ctl_count >= MAX_USER_CONTROLS)
889                 return -ENOMEM;
890         if (info->count > 1024)
891                 return -EINVAL;
892         access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
893                 (info->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
894                                  SNDRV_CTL_ELEM_ACCESS_INACTIVE));
895         info->id.numid = 0;
896         memset(&kctl, 0, sizeof(kctl));
897         down_write(&card->controls_rwsem);
898         _kctl = snd_ctl_find_id(card, &info->id);
899         err = 0;
900         if (_kctl) {
901                 if (replace)
902                         err = snd_ctl_remove(card, _kctl);
903                 else
904                         err = -EBUSY;
905         } else {
906                 if (replace)
907                         err = -ENOENT;
908         }
909         up_write(&card->controls_rwsem);
910         if (err < 0)
911                 return err;
912         memcpy(&kctl.id, &info->id, sizeof(info->id));
913         kctl.count = info->owner ? info->owner : 1;
914         access |= SNDRV_CTL_ELEM_ACCESS_USER;
915         kctl.info = snd_ctl_elem_user_info;
916         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
917                 kctl.get = snd_ctl_elem_user_get;
918         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
919                 kctl.put = snd_ctl_elem_user_put;
920         switch (info->type) {
921         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
922                 private_size = sizeof(char);
923                 if (info->count > 128)
924                         return -EINVAL;
925                 break;
926         case SNDRV_CTL_ELEM_TYPE_INTEGER:
927                 private_size = sizeof(long);
928                 if (info->count > 128)
929                         return -EINVAL;
930                 break;
931         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
932                 private_size = sizeof(long long);
933                 if (info->count > 64)
934                         return -EINVAL;
935                 break;
936         case SNDRV_CTL_ELEM_TYPE_BYTES:
937                 private_size = sizeof(unsigned char);
938                 if (info->count > 512)
939                         return -EINVAL;
940                 break;
941         case SNDRV_CTL_ELEM_TYPE_IEC958:
942                 private_size = sizeof(struct snd_aes_iec958);
943                 if (info->count != 1)
944                         return -EINVAL;
945                 break;
946         default:
947                 return -EINVAL;
948         }
949         private_size *= info->count;
950         ue = kzalloc(sizeof(struct user_element) + private_size, GFP_KERNEL);
951         if (ue == NULL)
952                 return -ENOMEM;
953         ue->info = *info;
954         ue->elem_data = (char *)ue + sizeof(*ue);
955         ue->elem_data_size = private_size;
956         kctl.private_free = snd_ctl_elem_user_free;
957         _kctl = snd_ctl_new(&kctl, access);
958         if (_kctl == NULL) {
959                 kfree(_kctl->private_data);
960                 return -ENOMEM;
961         }
962         _kctl->private_data = ue;
963         for (idx = 0; idx < _kctl->count; idx++)
964                 _kctl->vd[idx].owner = file;
965         err = snd_ctl_add(card, _kctl);
966         if (err < 0) {
967                 snd_ctl_free_one(_kctl);
968                 return err;
969         }
970
971         down_write(&card->controls_rwsem);
972         card->user_ctl_count++;
973         up_write(&card->controls_rwsem);
974
975         return 0;
976 }
977
978 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
979                                  struct snd_ctl_elem_info __user *_info, int replace)
980 {
981         struct snd_ctl_elem_info info;
982         if (copy_from_user(&info, _info, sizeof(info)))
983                 return -EFAULT;
984         return snd_ctl_elem_add(file, &info, replace);
985 }
986
987 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
988                                struct snd_ctl_elem_id __user *_id)
989 {
990         struct snd_ctl_elem_id id;
991         int err;
992
993         if (copy_from_user(&id, _id, sizeof(id)))
994                 return -EFAULT;
995         err = snd_ctl_remove_unlocked_id(file, &id);
996         if (! err) {
997                 struct snd_card *card = file->card;
998                 down_write(&card->controls_rwsem);
999                 card->user_ctl_count--;
1000                 up_write(&card->controls_rwsem);
1001         }
1002         return err;
1003 }
1004
1005 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1006 {
1007         int subscribe;
1008         if (get_user(subscribe, ptr))
1009                 return -EFAULT;
1010         if (subscribe < 0) {
1011                 subscribe = file->subscribed;
1012                 if (put_user(subscribe, ptr))
1013                         return -EFAULT;
1014                 return 0;
1015         }
1016         if (subscribe) {
1017                 file->subscribed = 1;
1018                 return 0;
1019         } else if (file->subscribed) {
1020                 snd_ctl_empty_read_queue(file);
1021                 file->subscribed = 0;
1022         }
1023         return 0;
1024 }
1025
1026 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1027 {
1028         struct snd_ctl_file *ctl;
1029         struct snd_card *card;
1030         struct list_head *list;
1031         struct snd_kctl_ioctl *p;
1032         void __user *argp = (void __user *)arg;
1033         int __user *ip = argp;
1034         int err;
1035
1036         ctl = file->private_data;
1037         card = ctl->card;
1038         snd_assert(card != NULL, return -ENXIO);
1039         switch (cmd) {
1040         case SNDRV_CTL_IOCTL_PVERSION:
1041                 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1042         case SNDRV_CTL_IOCTL_CARD_INFO:
1043                 return snd_ctl_card_info(card, ctl, cmd, argp);
1044         case SNDRV_CTL_IOCTL_ELEM_LIST:
1045                 return snd_ctl_elem_list(ctl->card, argp);
1046         case SNDRV_CTL_IOCTL_ELEM_INFO:
1047                 return snd_ctl_elem_info_user(ctl, argp);
1048         case SNDRV_CTL_IOCTL_ELEM_READ:
1049                 return snd_ctl_elem_read_user(ctl->card, argp);
1050         case SNDRV_CTL_IOCTL_ELEM_WRITE:
1051                 return snd_ctl_elem_write_user(ctl, argp);
1052         case SNDRV_CTL_IOCTL_ELEM_LOCK:
1053                 return snd_ctl_elem_lock(ctl, argp);
1054         case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1055                 return snd_ctl_elem_unlock(ctl, argp);
1056         case SNDRV_CTL_IOCTL_ELEM_ADD:
1057                 return snd_ctl_elem_add_user(ctl, argp, 0);
1058         case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1059                 return snd_ctl_elem_add_user(ctl, argp, 1);
1060         case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1061                 return snd_ctl_elem_remove(ctl, argp);
1062         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1063                 return snd_ctl_subscribe_events(ctl, ip);
1064         case SNDRV_CTL_IOCTL_POWER:
1065                 return -ENOPROTOOPT;
1066         case SNDRV_CTL_IOCTL_POWER_STATE:
1067 #ifdef CONFIG_PM
1068                 return put_user(card->power_state, ip) ? -EFAULT : 0;
1069 #else
1070                 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1071 #endif
1072         }
1073         down_read(&snd_ioctl_rwsem);
1074         list_for_each(list, &snd_control_ioctls) {
1075                 p = list_entry(list, struct snd_kctl_ioctl, list);
1076                 err = p->fioctl(card, ctl, cmd, arg);
1077                 if (err != -ENOIOCTLCMD) {
1078                         up_read(&snd_ioctl_rwsem);
1079                         return err;
1080                 }
1081         }
1082         up_read(&snd_ioctl_rwsem);
1083         snd_printdd("unknown ioctl = 0x%x\n", cmd);
1084         return -ENOTTY;
1085 }
1086
1087 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1088                             size_t count, loff_t * offset)
1089 {
1090         struct snd_ctl_file *ctl;
1091         int err = 0;
1092         ssize_t result = 0;
1093
1094         ctl = file->private_data;
1095         snd_assert(ctl != NULL && ctl->card != NULL, return -ENXIO);
1096         if (!ctl->subscribed)
1097                 return -EBADFD;
1098         if (count < sizeof(struct snd_ctl_event))
1099                 return -EINVAL;
1100         spin_lock_irq(&ctl->read_lock);
1101         while (count >= sizeof(struct snd_ctl_event)) {
1102                 struct snd_ctl_event ev;
1103                 struct snd_kctl_event *kev;
1104                 while (list_empty(&ctl->events)) {
1105                         wait_queue_t wait;
1106                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1107                                 err = -EAGAIN;
1108                                 goto __end_lock;
1109                         }
1110                         init_waitqueue_entry(&wait, current);
1111                         add_wait_queue(&ctl->change_sleep, &wait);
1112                         set_current_state(TASK_INTERRUPTIBLE);
1113                         spin_unlock_irq(&ctl->read_lock);
1114                         schedule();
1115                         remove_wait_queue(&ctl->change_sleep, &wait);
1116                         if (signal_pending(current))
1117                                 return result > 0 ? result : -ERESTARTSYS;
1118                         spin_lock_irq(&ctl->read_lock);
1119                 }
1120                 kev = snd_kctl_event(ctl->events.next);
1121                 ev.type = SNDRV_CTL_EVENT_ELEM;
1122                 ev.data.elem.mask = kev->mask;
1123                 ev.data.elem.id = kev->id;
1124                 list_del(&kev->list);
1125                 spin_unlock_irq(&ctl->read_lock);
1126                 kfree(kev);
1127                 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1128                         err = -EFAULT;
1129                         goto __end;
1130                 }
1131                 spin_lock_irq(&ctl->read_lock);
1132                 buffer += sizeof(struct snd_ctl_event);
1133                 count -= sizeof(struct snd_ctl_event);
1134                 result += sizeof(struct snd_ctl_event);
1135         }
1136       __end_lock:
1137         spin_unlock_irq(&ctl->read_lock);
1138       __end:
1139         return result > 0 ? result : err;
1140 }
1141
1142 static unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
1143 {
1144         unsigned int mask;
1145         struct snd_ctl_file *ctl;
1146
1147         ctl = file->private_data;
1148         if (!ctl->subscribed)
1149                 return 0;
1150         poll_wait(file, &ctl->change_sleep, wait);
1151
1152         mask = 0;
1153         if (!list_empty(&ctl->events))
1154                 mask |= POLLIN | POLLRDNORM;
1155
1156         return mask;
1157 }
1158
1159 /*
1160  * register the device-specific control-ioctls.
1161  * called from each device manager like pcm.c, hwdep.c, etc.
1162  */
1163 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1164 {
1165         struct snd_kctl_ioctl *pn;
1166
1167         pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1168         if (pn == NULL)
1169                 return -ENOMEM;
1170         pn->fioctl = fcn;
1171         down_write(&snd_ioctl_rwsem);
1172         list_add_tail(&pn->list, lists);
1173         up_write(&snd_ioctl_rwsem);
1174         return 0;
1175 }
1176
1177 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1178 {
1179         return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1180 }
1181
1182 #ifdef CONFIG_COMPAT
1183 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1184 {
1185         return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1186 }
1187 #endif
1188
1189 /*
1190  * de-register the device-specific control-ioctls.
1191  */
1192 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1193                                      struct list_head *lists)
1194 {
1195         struct list_head *list;
1196         struct snd_kctl_ioctl *p;
1197
1198         snd_assert(fcn != NULL, return -EINVAL);
1199         down_write(&snd_ioctl_rwsem);
1200         list_for_each(list, lists) {
1201                 p = list_entry(list, struct snd_kctl_ioctl, list);
1202                 if (p->fioctl == fcn) {
1203                         list_del(&p->list);
1204                         up_write(&snd_ioctl_rwsem);
1205                         kfree(p);
1206                         return 0;
1207                 }
1208         }
1209         up_write(&snd_ioctl_rwsem);
1210         snd_BUG();
1211         return -EINVAL;
1212 }
1213
1214 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1215 {
1216         return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1217 }
1218
1219 #ifdef CONFIG_COMPAT
1220 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1221 {
1222         return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1223 }
1224
1225 #endif
1226
1227 static int snd_ctl_fasync(int fd, struct file * file, int on)
1228 {
1229         struct snd_ctl_file *ctl;
1230         int err;
1231         ctl = file->private_data;
1232         err = fasync_helper(fd, file, on, &ctl->fasync);
1233         if (err < 0)
1234                 return err;
1235         return 0;
1236 }
1237
1238 /*
1239  * ioctl32 compat
1240  */
1241 #ifdef CONFIG_COMPAT
1242 #include "control_compat.c"
1243 #else
1244 #define snd_ctl_ioctl_compat    NULL
1245 #endif
1246
1247 /*
1248  *  INIT PART
1249  */
1250
1251 static struct file_operations snd_ctl_f_ops =
1252 {
1253         .owner =        THIS_MODULE,
1254         .read =         snd_ctl_read,
1255         .open =         snd_ctl_open,
1256         .release =      snd_ctl_release,
1257         .poll =         snd_ctl_poll,
1258         .unlocked_ioctl =       snd_ctl_ioctl,
1259         .compat_ioctl = snd_ctl_ioctl_compat,
1260         .fasync =       snd_ctl_fasync,
1261 };
1262
1263 static struct snd_minor snd_ctl_reg =
1264 {
1265         .comment =      "ctl",
1266         .f_ops =        &snd_ctl_f_ops,
1267 };
1268
1269 /*
1270  * registration of the control device
1271  */
1272 static int snd_ctl_dev_register(struct snd_device *device)
1273 {
1274         struct snd_card *card = device->device_data;
1275         int err, cardnum;
1276         char name[16];
1277
1278         snd_assert(card != NULL, return -ENXIO);
1279         cardnum = card->number;
1280         snd_assert(cardnum >= 0 && cardnum < SNDRV_CARDS, return -ENXIO);
1281         sprintf(name, "controlC%i", cardnum);
1282         if ((err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL,
1283                                         card, 0, &snd_ctl_reg, name)) < 0)
1284                 return err;
1285         return 0;
1286 }
1287
1288 /*
1289  * disconnection of the control device
1290  */
1291 static int snd_ctl_dev_disconnect(struct snd_device *device)
1292 {
1293         struct snd_card *card = device->device_data;
1294         struct list_head *flist;
1295         struct snd_ctl_file *ctl;
1296
1297         down_read(&card->controls_rwsem);
1298         list_for_each(flist, &card->ctl_files) {
1299                 ctl = snd_ctl_file(flist);
1300                 wake_up(&ctl->change_sleep);
1301                 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1302         }
1303         up_read(&card->controls_rwsem);
1304         return 0;
1305 }
1306
1307 /*
1308  * free all controls
1309  */
1310 static int snd_ctl_dev_free(struct snd_device *device)
1311 {
1312         struct snd_card *card = device->device_data;
1313         struct snd_kcontrol *control;
1314
1315         down_write(&card->controls_rwsem);
1316         while (!list_empty(&card->controls)) {
1317                 control = snd_kcontrol(card->controls.next);
1318                 snd_ctl_remove(card, control);
1319         }
1320         up_write(&card->controls_rwsem);
1321         return 0;
1322 }
1323
1324 /*
1325  * de-registration of the control device
1326  */
1327 static int snd_ctl_dev_unregister(struct snd_device *device)
1328 {
1329         struct snd_card *card = device->device_data;
1330         int err, cardnum;
1331
1332         snd_assert(card != NULL, return -ENXIO);
1333         cardnum = card->number;
1334         snd_assert(cardnum >= 0 && cardnum < SNDRV_CARDS, return -ENXIO);
1335         if ((err = snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL, card, 0)) < 0)
1336                 return err;
1337         return snd_ctl_dev_free(device);
1338 }
1339
1340 /*
1341  * create control core:
1342  * called from init.c
1343  */
1344 int snd_ctl_create(struct snd_card *card)
1345 {
1346         static struct snd_device_ops ops = {
1347                 .dev_free = snd_ctl_dev_free,
1348                 .dev_register = snd_ctl_dev_register,
1349                 .dev_disconnect = snd_ctl_dev_disconnect,
1350                 .dev_unregister = snd_ctl_dev_unregister
1351         };
1352
1353         snd_assert(card != NULL, return -ENXIO);
1354         return snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1355 }