Merge branch 'cris_move' of git://www.jni.nu/cris
[linux-2.6] / sound / core / init.c
1 /*
2  *  Initialization routines
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/init.h>
23 #include <linux/sched.h>
24 #include <linux/file.h>
25 #include <linux/slab.h>
26 #include <linux/time.h>
27 #include <linux/ctype.h>
28 #include <linux/pm.h>
29
30 #include <sound/core.h>
31 #include <sound/control.h>
32 #include <sound/info.h>
33
34 static DEFINE_SPINLOCK(shutdown_lock);
35 static LIST_HEAD(shutdown_files);
36
37 static const struct file_operations snd_shutdown_f_ops;
38
39 static unsigned int snd_cards_lock;     /* locked for registering/using */
40 struct snd_card *snd_cards[SNDRV_CARDS];
41 EXPORT_SYMBOL(snd_cards);
42
43 static DEFINE_MUTEX(snd_card_mutex);
44
45 static char *slots[SNDRV_CARDS];
46 module_param_array(slots, charp, NULL, 0444);
47 MODULE_PARM_DESC(slots, "Module names assigned to the slots.");
48
49 /* return non-zero if the given index is reserved for the given
50  * module via slots option
51  */
52 static int module_slot_match(struct module *module, int idx)
53 {
54         int match = 1;
55 #ifdef MODULE
56         const char *s1, *s2;
57
58         if (!module || !module->name || !slots[idx])
59                 return 0;
60
61         s1 = module->name;
62         s2 = slots[idx];
63         if (*s2 == '!') {
64                 match = 0; /* negative match */
65                 s2++;
66         }
67         /* compare module name strings
68          * hyphens are handled as equivalent with underscore
69          */
70         for (;;) {
71                 char c1 = *s1++;
72                 char c2 = *s2++;
73                 if (c1 == '-')
74                         c1 = '_';
75                 if (c2 == '-')
76                         c2 = '_';
77                 if (c1 != c2)
78                         return !match;
79                 if (!c1)
80                         break;
81         }
82 #endif /* MODULE */
83         return match;
84 }
85
86 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
87 int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
88 EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
89 #endif
90
91 #ifdef CONFIG_PROC_FS
92 static void snd_card_id_read(struct snd_info_entry *entry,
93                              struct snd_info_buffer *buffer)
94 {
95         snd_iprintf(buffer, "%s\n", entry->card->id);
96 }
97
98 static inline int init_info_for_card(struct snd_card *card)
99 {
100         int err;
101         struct snd_info_entry *entry;
102
103         if ((err = snd_info_card_register(card)) < 0) {
104                 snd_printd("unable to create card info\n");
105                 return err;
106         }
107         if ((entry = snd_info_create_card_entry(card, "id", card->proc_root)) == NULL) {
108                 snd_printd("unable to create card entry\n");
109                 return err;
110         }
111         entry->c.text.read = snd_card_id_read;
112         if (snd_info_register(entry) < 0) {
113                 snd_info_free_entry(entry);
114                 entry = NULL;
115         }
116         card->proc_id = entry;
117         return 0;
118 }
119 #else /* !CONFIG_PROC_FS */
120 #define init_info_for_card(card)
121 #endif
122
123 /**
124  *  snd_card_new - create and initialize a soundcard structure
125  *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
126  *  @xid: card identification (ASCII string)
127  *  @module: top level module for locking
128  *  @extra_size: allocate this extra size after the main soundcard structure
129  *
130  *  Creates and initializes a soundcard structure.
131  *
132  *  Returns kmallocated snd_card structure. Creates the ALSA control interface
133  *  (which is blocked until snd_card_register function is called).
134  */
135 struct snd_card *snd_card_new(int idx, const char *xid,
136                          struct module *module, int extra_size)
137 {
138         struct snd_card *card;
139         int err, idx2;
140
141         if (extra_size < 0)
142                 extra_size = 0;
143         card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
144         if (card == NULL)
145                 return NULL;
146         if (xid) {
147                 if (!snd_info_check_reserved_words(xid))
148                         goto __error;
149                 strlcpy(card->id, xid, sizeof(card->id));
150         }
151         err = 0;
152         mutex_lock(&snd_card_mutex);
153         if (idx < 0) {
154                 for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
155                         /* idx == -1 == 0xffff means: take any free slot */
156                         if (~snd_cards_lock & idx & 1<<idx2) {
157                                 if (module_slot_match(module, idx2)) {
158                                         idx = idx2;
159                                         break;
160                                 }
161                         }
162         }
163         if (idx < 0) {
164                 for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
165                         /* idx == -1 == 0xffff means: take any free slot */
166                         if (~snd_cards_lock & idx & 1<<idx2) {
167                                 if (!slots[idx2] || !*slots[idx2]) {
168                                         idx = idx2;
169                                         break;
170                                 }
171                         }
172         }
173         if (idx < 0)
174                 err = -ENODEV;
175         else if (idx < snd_ecards_limit) {
176                 if (snd_cards_lock & (1 << idx))
177                         err = -EBUSY;   /* invalid */
178         } else if (idx >= SNDRV_CARDS)
179                 err = -ENODEV;
180         if (err < 0) {
181                 mutex_unlock(&snd_card_mutex);
182                 snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i), error: %d\n",
183                          idx, snd_ecards_limit - 1, err);
184                 goto __error;
185         }
186         snd_cards_lock |= 1 << idx;             /* lock it */
187         if (idx >= snd_ecards_limit)
188                 snd_ecards_limit = idx + 1; /* increase the limit */
189         mutex_unlock(&snd_card_mutex);
190         card->number = idx;
191         card->module = module;
192         INIT_LIST_HEAD(&card->devices);
193         init_rwsem(&card->controls_rwsem);
194         rwlock_init(&card->ctl_files_rwlock);
195         INIT_LIST_HEAD(&card->controls);
196         INIT_LIST_HEAD(&card->ctl_files);
197         spin_lock_init(&card->files_lock);
198         init_waitqueue_head(&card->shutdown_sleep);
199 #ifdef CONFIG_PM
200         mutex_init(&card->power_lock);
201         init_waitqueue_head(&card->power_sleep);
202 #endif
203         /* the control interface cannot be accessed from the user space until */
204         /* snd_cards_bitmask and snd_cards are set with snd_card_register */
205         if ((err = snd_ctl_create(card)) < 0) {
206                 snd_printd("unable to register control minors\n");
207                 goto __error;
208         }
209         if ((err = snd_info_card_create(card)) < 0) {
210                 snd_printd("unable to create card info\n");
211                 goto __error_ctl;
212         }
213         if (extra_size > 0)
214                 card->private_data = (char *)card + sizeof(struct snd_card);
215         return card;
216
217       __error_ctl:
218         snd_device_free_all(card, SNDRV_DEV_CMD_PRE);
219       __error:
220         kfree(card);
221         return NULL;
222 }
223
224 EXPORT_SYMBOL(snd_card_new);
225
226 /* return non-zero if a card is already locked */
227 int snd_card_locked(int card)
228 {
229         int locked;
230
231         mutex_lock(&snd_card_mutex);
232         locked = snd_cards_lock & (1 << card);
233         mutex_unlock(&snd_card_mutex);
234         return locked;
235 }
236
237 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
238 {
239         return -ENODEV;
240 }
241
242 static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
243                                    size_t count, loff_t *offset)
244 {
245         return -ENODEV;
246 }
247
248 static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
249                                     size_t count, loff_t *offset)
250 {
251         return -ENODEV;
252 }
253
254 static int snd_disconnect_release(struct inode *inode, struct file *file)
255 {
256         struct snd_monitor_file *df = NULL, *_df;
257
258         spin_lock(&shutdown_lock);
259         list_for_each_entry(_df, &shutdown_files, shutdown_list) {
260                 if (_df->file == file) {
261                         df = _df;
262                         break;
263                 }
264         }
265         spin_unlock(&shutdown_lock);
266
267         if (likely(df)) {
268                 if ((file->f_flags & FASYNC) && df->disconnected_f_op->fasync)
269                         df->disconnected_f_op->fasync(-1, file, 0);
270                 return df->disconnected_f_op->release(inode, file);
271         }
272
273         panic("%s(%p, %p) failed!", __func__, inode, file);
274 }
275
276 static unsigned int snd_disconnect_poll(struct file * file, poll_table * wait)
277 {
278         return POLLERR | POLLNVAL;
279 }
280
281 static long snd_disconnect_ioctl(struct file *file,
282                                  unsigned int cmd, unsigned long arg)
283 {
284         return -ENODEV;
285 }
286
287 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
288 {
289         return -ENODEV;
290 }
291
292 static int snd_disconnect_fasync(int fd, struct file *file, int on)
293 {
294         return -ENODEV;
295 }
296
297 static const struct file_operations snd_shutdown_f_ops =
298 {
299         .owner =        THIS_MODULE,
300         .llseek =       snd_disconnect_llseek,
301         .read =         snd_disconnect_read,
302         .write =        snd_disconnect_write,
303         .release =      snd_disconnect_release,
304         .poll =         snd_disconnect_poll,
305         .unlocked_ioctl = snd_disconnect_ioctl,
306 #ifdef CONFIG_COMPAT
307         .compat_ioctl = snd_disconnect_ioctl,
308 #endif
309         .mmap =         snd_disconnect_mmap,
310         .fasync =       snd_disconnect_fasync
311 };
312
313 /**
314  *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
315  *  @card: soundcard structure
316  *
317  *  Disconnects all APIs from the file-operations (user space).
318  *
319  *  Returns zero, otherwise a negative error code.
320  *
321  *  Note: The current implementation replaces all active file->f_op with special
322  *        dummy file operations (they do nothing except release).
323  */
324 int snd_card_disconnect(struct snd_card *card)
325 {
326         struct snd_monitor_file *mfile;
327         struct file *file;
328         int err;
329
330         if (!card)
331                 return -EINVAL;
332
333         spin_lock(&card->files_lock);
334         if (card->shutdown) {
335                 spin_unlock(&card->files_lock);
336                 return 0;
337         }
338         card->shutdown = 1;
339         spin_unlock(&card->files_lock);
340
341         /* phase 1: disable fops (user space) operations for ALSA API */
342         mutex_lock(&snd_card_mutex);
343         snd_cards[card->number] = NULL;
344         snd_cards_lock &= ~(1 << card->number);
345         mutex_unlock(&snd_card_mutex);
346         
347         /* phase 2: replace file->f_op with special dummy operations */
348         
349         spin_lock(&card->files_lock);
350         mfile = card->files;
351         while (mfile) {
352                 file = mfile->file;
353
354                 /* it's critical part, use endless loop */
355                 /* we have no room to fail */
356                 mfile->disconnected_f_op = mfile->file->f_op;
357
358                 spin_lock(&shutdown_lock);
359                 list_add(&mfile->shutdown_list, &shutdown_files);
360                 spin_unlock(&shutdown_lock);
361
362                 mfile->file->f_op = &snd_shutdown_f_ops;
363                 fops_get(mfile->file->f_op);
364                 
365                 mfile = mfile->next;
366         }
367         spin_unlock(&card->files_lock); 
368
369         /* phase 3: notify all connected devices about disconnection */
370         /* at this point, they cannot respond to any calls except release() */
371
372 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
373         if (snd_mixer_oss_notify_callback)
374                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
375 #endif
376
377         /* notify all devices that we are disconnected */
378         err = snd_device_disconnect_all(card);
379         if (err < 0)
380                 snd_printk(KERN_ERR "not all devices for card %i can be disconnected\n", card->number);
381
382         snd_info_card_disconnect(card);
383 #ifndef CONFIG_SYSFS_DEPRECATED
384         if (card->card_dev) {
385                 device_unregister(card->card_dev);
386                 card->card_dev = NULL;
387         }
388 #endif
389 #ifdef CONFIG_PM
390         wake_up(&card->power_sleep);
391 #endif
392         return 0;       
393 }
394
395 EXPORT_SYMBOL(snd_card_disconnect);
396
397 /**
398  *  snd_card_free - frees given soundcard structure
399  *  @card: soundcard structure
400  *
401  *  This function releases the soundcard structure and the all assigned
402  *  devices automatically.  That is, you don't have to release the devices
403  *  by yourself.
404  *
405  *  Returns zero. Frees all associated devices and frees the control
406  *  interface associated to given soundcard.
407  */
408 static int snd_card_do_free(struct snd_card *card)
409 {
410 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
411         if (snd_mixer_oss_notify_callback)
412                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
413 #endif
414         if (snd_device_free_all(card, SNDRV_DEV_CMD_PRE) < 0) {
415                 snd_printk(KERN_ERR "unable to free all devices (pre)\n");
416                 /* Fatal, but this situation should never occur */
417         }
418         if (snd_device_free_all(card, SNDRV_DEV_CMD_NORMAL) < 0) {
419                 snd_printk(KERN_ERR "unable to free all devices (normal)\n");
420                 /* Fatal, but this situation should never occur */
421         }
422         if (snd_device_free_all(card, SNDRV_DEV_CMD_POST) < 0) {
423                 snd_printk(KERN_ERR "unable to free all devices (post)\n");
424                 /* Fatal, but this situation should never occur */
425         }
426         if (card->private_free)
427                 card->private_free(card);
428         snd_info_free_entry(card->proc_id);
429         if (snd_info_card_free(card) < 0) {
430                 snd_printk(KERN_WARNING "unable to free card info\n");
431                 /* Not fatal error */
432         }
433         kfree(card);
434         return 0;
435 }
436
437 int snd_card_free_when_closed(struct snd_card *card)
438 {
439         int free_now = 0;
440         int ret = snd_card_disconnect(card);
441         if (ret)
442                 return ret;
443
444         spin_lock(&card->files_lock);
445         if (card->files == NULL)
446                 free_now = 1;
447         else
448                 card->free_on_last_close = 1;
449         spin_unlock(&card->files_lock);
450
451         if (free_now)
452                 snd_card_do_free(card);
453         return 0;
454 }
455
456 EXPORT_SYMBOL(snd_card_free_when_closed);
457
458 int snd_card_free(struct snd_card *card)
459 {
460         int ret = snd_card_disconnect(card);
461         if (ret)
462                 return ret;
463
464         /* wait, until all devices are ready for the free operation */
465         wait_event(card->shutdown_sleep, card->files == NULL);
466         snd_card_do_free(card);
467         return 0;
468 }
469
470 EXPORT_SYMBOL(snd_card_free);
471
472 static void choose_default_id(struct snd_card *card)
473 {
474         int i, len, idx_flag = 0, loops = SNDRV_CARDS;
475         char *id, *spos;
476         
477         id = spos = card->shortname;    
478         while (*id != '\0') {
479                 if (*id == ' ')
480                         spos = id + 1;
481                 id++;
482         }
483         id = card->id;
484         while (*spos != '\0' && !isalnum(*spos))
485                 spos++;
486         if (isdigit(*spos))
487                 *id++ = isalpha(card->shortname[0]) ? card->shortname[0] : 'D';
488         while (*spos != '\0' && (size_t)(id - card->id) < sizeof(card->id) - 1) {
489                 if (isalnum(*spos))
490                         *id++ = *spos;
491                 spos++;
492         }
493         *id = '\0';
494
495         id = card->id;
496         
497         if (*id == '\0')
498                 strcpy(id, "default");
499
500         while (1) {
501                 if (loops-- == 0) {
502                         snd_printk(KERN_ERR "unable to choose default card id (%s)\n", id);
503                         strcpy(card->id, card->proc_root->name);
504                         return;
505                 }
506                 if (!snd_info_check_reserved_words(id))
507                         goto __change;
508                 for (i = 0; i < snd_ecards_limit; i++) {
509                         if (snd_cards[i] && !strcmp(snd_cards[i]->id, id))
510                                 goto __change;
511                 }
512                 break;
513
514               __change:
515                 len = strlen(id);
516                 if (idx_flag) {
517                         if (id[len-1] != '9')
518                                 id[len-1]++;
519                         else
520                                 id[len-1] = 'A';
521                 } else if ((size_t)len <= sizeof(card->id) - 3) {
522                         strcat(id, "_1");
523                         idx_flag++;
524                 } else {
525                         spos = id + len - 2;
526                         if ((size_t)len <= sizeof(card->id) - 2)
527                                 spos++;
528                         *spos++ = '_';
529                         *spos++ = '1';
530                         *spos++ = '\0';
531                         idx_flag++;
532                 }
533         }
534 }
535
536 /**
537  *  snd_card_register - register the soundcard
538  *  @card: soundcard structure
539  *
540  *  This function registers all the devices assigned to the soundcard.
541  *  Until calling this, the ALSA control interface is blocked from the
542  *  external accesses.  Thus, you should call this function at the end
543  *  of the initialization of the card.
544  *
545  *  Returns zero otherwise a negative error code if the registrain failed.
546  */
547 int snd_card_register(struct snd_card *card)
548 {
549         int err;
550
551         if (snd_BUG_ON(!card))
552                 return -EINVAL;
553 #ifndef CONFIG_SYSFS_DEPRECATED
554         if (!card->card_dev) {
555                 card->card_dev = device_create(sound_class, card->dev,
556                                                MKDEV(0, 0), NULL,
557                                                "card%i", card->number);
558                 if (IS_ERR(card->card_dev))
559                         card->card_dev = NULL;
560         }
561 #endif
562         if ((err = snd_device_register_all(card)) < 0)
563                 return err;
564         mutex_lock(&snd_card_mutex);
565         if (snd_cards[card->number]) {
566                 /* already registered */
567                 mutex_unlock(&snd_card_mutex);
568                 return 0;
569         }
570         if (card->id[0] == '\0')
571                 choose_default_id(card);
572         snd_cards[card->number] = card;
573         mutex_unlock(&snd_card_mutex);
574         init_info_for_card(card);
575 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
576         if (snd_mixer_oss_notify_callback)
577                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
578 #endif
579         return 0;
580 }
581
582 EXPORT_SYMBOL(snd_card_register);
583
584 #ifdef CONFIG_PROC_FS
585 static struct snd_info_entry *snd_card_info_entry;
586
587 static void snd_card_info_read(struct snd_info_entry *entry,
588                                struct snd_info_buffer *buffer)
589 {
590         int idx, count;
591         struct snd_card *card;
592
593         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
594                 mutex_lock(&snd_card_mutex);
595                 if ((card = snd_cards[idx]) != NULL) {
596                         count++;
597                         snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
598                                         idx,
599                                         card->id,
600                                         card->driver,
601                                         card->shortname);
602                         snd_iprintf(buffer, "                      %s\n",
603                                         card->longname);
604                 }
605                 mutex_unlock(&snd_card_mutex);
606         }
607         if (!count)
608                 snd_iprintf(buffer, "--- no soundcards ---\n");
609 }
610
611 #ifdef CONFIG_SND_OSSEMUL
612
613 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
614 {
615         int idx, count;
616         struct snd_card *card;
617
618         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
619                 mutex_lock(&snd_card_mutex);
620                 if ((card = snd_cards[idx]) != NULL) {
621                         count++;
622                         snd_iprintf(buffer, "%s\n", card->longname);
623                 }
624                 mutex_unlock(&snd_card_mutex);
625         }
626         if (!count) {
627                 snd_iprintf(buffer, "--- no soundcards ---\n");
628         }
629 }
630
631 #endif
632
633 #ifdef MODULE
634 static struct snd_info_entry *snd_card_module_info_entry;
635 static void snd_card_module_info_read(struct snd_info_entry *entry,
636                                       struct snd_info_buffer *buffer)
637 {
638         int idx;
639         struct snd_card *card;
640
641         for (idx = 0; idx < SNDRV_CARDS; idx++) {
642                 mutex_lock(&snd_card_mutex);
643                 if ((card = snd_cards[idx]) != NULL)
644                         snd_iprintf(buffer, "%2i %s\n",
645                                     idx, card->module->name);
646                 mutex_unlock(&snd_card_mutex);
647         }
648 }
649 #endif
650
651 int __init snd_card_info_init(void)
652 {
653         struct snd_info_entry *entry;
654
655         entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
656         if (! entry)
657                 return -ENOMEM;
658         entry->c.text.read = snd_card_info_read;
659         if (snd_info_register(entry) < 0) {
660                 snd_info_free_entry(entry);
661                 return -ENOMEM;
662         }
663         snd_card_info_entry = entry;
664
665 #ifdef MODULE
666         entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
667         if (entry) {
668                 entry->c.text.read = snd_card_module_info_read;
669                 if (snd_info_register(entry) < 0)
670                         snd_info_free_entry(entry);
671                 else
672                         snd_card_module_info_entry = entry;
673         }
674 #endif
675
676         return 0;
677 }
678
679 int __exit snd_card_info_done(void)
680 {
681         snd_info_free_entry(snd_card_info_entry);
682 #ifdef MODULE
683         snd_info_free_entry(snd_card_module_info_entry);
684 #endif
685         return 0;
686 }
687
688 #endif /* CONFIG_PROC_FS */
689
690 /**
691  *  snd_component_add - add a component string
692  *  @card: soundcard structure
693  *  @component: the component id string
694  *
695  *  This function adds the component id string to the supported list.
696  *  The component can be referred from the alsa-lib.
697  *
698  *  Returns zero otherwise a negative error code.
699  */
700   
701 int snd_component_add(struct snd_card *card, const char *component)
702 {
703         char *ptr;
704         int len = strlen(component);
705
706         ptr = strstr(card->components, component);
707         if (ptr != NULL) {
708                 if (ptr[len] == '\0' || ptr[len] == ' ')        /* already there */
709                         return 1;
710         }
711         if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
712                 snd_BUG();
713                 return -ENOMEM;
714         }
715         if (card->components[0] != '\0')
716                 strcat(card->components, " ");
717         strcat(card->components, component);
718         return 0;
719 }
720
721 EXPORT_SYMBOL(snd_component_add);
722
723 /**
724  *  snd_card_file_add - add the file to the file list of the card
725  *  @card: soundcard structure
726  *  @file: file pointer
727  *
728  *  This function adds the file to the file linked-list of the card.
729  *  This linked-list is used to keep tracking the connection state,
730  *  and to avoid the release of busy resources by hotplug.
731  *
732  *  Returns zero or a negative error code.
733  */
734 int snd_card_file_add(struct snd_card *card, struct file *file)
735 {
736         struct snd_monitor_file *mfile;
737
738         mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
739         if (mfile == NULL)
740                 return -ENOMEM;
741         mfile->file = file;
742         mfile->disconnected_f_op = NULL;
743         mfile->next = NULL;
744         spin_lock(&card->files_lock);
745         if (card->shutdown) {
746                 spin_unlock(&card->files_lock);
747                 kfree(mfile);
748                 return -ENODEV;
749         }
750         mfile->next = card->files;
751         card->files = mfile;
752         spin_unlock(&card->files_lock);
753         return 0;
754 }
755
756 EXPORT_SYMBOL(snd_card_file_add);
757
758 /**
759  *  snd_card_file_remove - remove the file from the file list
760  *  @card: soundcard structure
761  *  @file: file pointer
762  *
763  *  This function removes the file formerly added to the card via
764  *  snd_card_file_add() function.
765  *  If all files are removed and snd_card_free_when_closed() was
766  *  called beforehand, it processes the pending release of
767  *  resources.
768  *
769  *  Returns zero or a negative error code.
770  */
771 int snd_card_file_remove(struct snd_card *card, struct file *file)
772 {
773         struct snd_monitor_file *mfile, *pfile = NULL;
774         int last_close = 0;
775
776         spin_lock(&card->files_lock);
777         mfile = card->files;
778         while (mfile) {
779                 if (mfile->file == file) {
780                         if (pfile)
781                                 pfile->next = mfile->next;
782                         else
783                                 card->files = mfile->next;
784                         break;
785                 }
786                 pfile = mfile;
787                 mfile = mfile->next;
788         }
789         if (mfile && mfile->disconnected_f_op) {
790                 fops_put(mfile->disconnected_f_op);
791                 spin_lock(&shutdown_lock);
792                 list_del(&mfile->shutdown_list);
793                 spin_unlock(&shutdown_lock);
794         }
795         if (card->files == NULL)
796                 last_close = 1;
797         spin_unlock(&card->files_lock);
798         if (last_close) {
799                 wake_up(&card->shutdown_sleep);
800                 if (card->free_on_last_close)
801                         snd_card_do_free(card);
802         }
803         if (!mfile) {
804                 snd_printk(KERN_ERR "ALSA card file remove problem (%p)\n", file);
805                 return -ENOENT;
806         }
807         kfree(mfile);
808         return 0;
809 }
810
811 EXPORT_SYMBOL(snd_card_file_remove);
812
813 #ifdef CONFIG_PM
814 /**
815  *  snd_power_wait - wait until the power-state is changed.
816  *  @card: soundcard structure
817  *  @power_state: expected power state
818  *
819  *  Waits until the power-state is changed.
820  *
821  *  Note: the power lock must be active before call.
822  */
823 int snd_power_wait(struct snd_card *card, unsigned int power_state)
824 {
825         wait_queue_t wait;
826         int result = 0;
827
828         /* fastpath */
829         if (snd_power_get_state(card) == power_state)
830                 return 0;
831         init_waitqueue_entry(&wait, current);
832         add_wait_queue(&card->power_sleep, &wait);
833         while (1) {
834                 if (card->shutdown) {
835                         result = -ENODEV;
836                         break;
837                 }
838                 if (snd_power_get_state(card) == power_state)
839                         break;
840                 set_current_state(TASK_UNINTERRUPTIBLE);
841                 snd_power_unlock(card);
842                 schedule_timeout(30 * HZ);
843                 snd_power_lock(card);
844         }
845         remove_wait_queue(&card->power_sleep, &wait);
846         return result;
847 }
848
849 EXPORT_SYMBOL(snd_power_wait);
850 #endif /* CONFIG_PM */