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TOMOYO Linux Cross Reference
Linux/sound/core/init.c

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  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/module.h>
 25 #include <linux/device.h>
 26 #include <linux/file.h>
 27 #include <linux/slab.h>
 28 #include <linux/time.h>
 29 #include <linux/ctype.h>
 30 #include <linux/pm.h>
 31 #include <linux/completion.h>
 32 
 33 #include <sound/core.h>
 34 #include <sound/control.h>
 35 #include <sound/info.h>
 36 
 37 /* monitor files for graceful shutdown (hotplug) */
 38 struct snd_monitor_file {
 39         struct file *file;
 40         const struct file_operations *disconnected_f_op;
 41         struct list_head shutdown_list; /* still need to shutdown */
 42         struct list_head list;  /* link of monitor files */
 43 };
 44 
 45 static DEFINE_SPINLOCK(shutdown_lock);
 46 static LIST_HEAD(shutdown_files);
 47 
 48 static const struct file_operations snd_shutdown_f_ops;
 49 
 50 /* locked for registering/using */
 51 static DECLARE_BITMAP(snd_cards_lock, SNDRV_CARDS);
 52 struct snd_card *snd_cards[SNDRV_CARDS];
 53 EXPORT_SYMBOL(snd_cards);
 54 
 55 static DEFINE_MUTEX(snd_card_mutex);
 56 
 57 static char *slots[SNDRV_CARDS];
 58 module_param_array(slots, charp, NULL, 0444);
 59 MODULE_PARM_DESC(slots, "Module names assigned to the slots.");
 60 
 61 /* return non-zero if the given index is reserved for the given
 62  * module via slots option
 63  */
 64 static int module_slot_match(struct module *module, int idx)
 65 {
 66         int match = 1;
 67 #ifdef MODULE
 68         const char *s1, *s2;
 69 
 70         if (!module || !*module->name || !slots[idx])
 71                 return 0;
 72 
 73         s1 = module->name;
 74         s2 = slots[idx];
 75         if (*s2 == '!') {
 76                 match = 0; /* negative match */
 77                 s2++;
 78         }
 79         /* compare module name strings
 80          * hyphens are handled as equivalent with underscore
 81          */
 82         for (;;) {
 83                 char c1 = *s1++;
 84                 char c2 = *s2++;
 85                 if (c1 == '-')
 86                         c1 = '_';
 87                 if (c2 == '-')
 88                         c2 = '_';
 89                 if (c1 != c2)
 90                         return !match;
 91                 if (!c1)
 92                         break;
 93         }
 94 #endif /* MODULE */
 95         return match;
 96 }
 97 
 98 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 99 int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
100 EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
101 #endif
102 
103 #ifdef CONFIG_SND_PROC_FS
104 static void snd_card_id_read(struct snd_info_entry *entry,
105                              struct snd_info_buffer *buffer)
106 {
107         snd_iprintf(buffer, "%s\n", entry->card->id);
108 }
109 
110 static int init_info_for_card(struct snd_card *card)
111 {
112         struct snd_info_entry *entry;
113 
114         entry = snd_info_create_card_entry(card, "id", card->proc_root);
115         if (!entry) {
116                 dev_dbg(card->dev, "unable to create card entry\n");
117                 return -ENOMEM;
118         }
119         entry->c.text.read = snd_card_id_read;
120         card->proc_id = entry;
121 
122         return snd_info_card_register(card);
123 }
124 #else /* !CONFIG_SND_PROC_FS */
125 #define init_info_for_card(card)
126 #endif
127 
128 static int check_empty_slot(struct module *module, int slot)
129 {
130         return !slots[slot] || !*slots[slot];
131 }
132 
133 /* return an empty slot number (>= 0) found in the given bitmask @mask.
134  * @mask == -1 == 0xffffffff means: take any free slot up to 32
135  * when no slot is available, return the original @mask as is.
136  */
137 static int get_slot_from_bitmask(int mask, int (*check)(struct module *, int),
138                                  struct module *module)
139 {
140         int slot;
141 
142         for (slot = 0; slot < SNDRV_CARDS; slot++) {
143                 if (slot < 32 && !(mask & (1U << slot)))
144                         continue;
145                 if (!test_bit(slot, snd_cards_lock)) {
146                         if (check(module, slot))
147                                 return slot; /* found */
148                 }
149         }
150         return mask; /* unchanged */
151 }
152 
153 /* the default release callback set in snd_device_initialize() below;
154  * this is just NOP for now, as almost all jobs are already done in
155  * dev_free callback of snd_device chain instead.
156  */
157 static void default_release(struct device *dev)
158 {
159 }
160 
161 /**
162  * snd_device_initialize - Initialize struct device for sound devices
163  * @dev: device to initialize
164  * @card: card to assign, optional
165  */
166 void snd_device_initialize(struct device *dev, struct snd_card *card)
167 {
168         device_initialize(dev);
169         if (card)
170                 dev->parent = &card->card_dev;
171         dev->class = sound_class;
172         dev->release = default_release;
173 }
174 EXPORT_SYMBOL_GPL(snd_device_initialize);
175 
176 static int snd_card_do_free(struct snd_card *card);
177 static const struct attribute_group card_dev_attr_group;
178 
179 static void release_card_device(struct device *dev)
180 {
181         snd_card_do_free(dev_to_snd_card(dev));
182 }
183 
184 /**
185  *  snd_card_new - create and initialize a soundcard structure
186  *  @parent: the parent device object
187  *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
188  *  @xid: card identification (ASCII string)
189  *  @module: top level module for locking
190  *  @extra_size: allocate this extra size after the main soundcard structure
191  *  @card_ret: the pointer to store the created card instance
192  *
193  *  Creates and initializes a soundcard structure.
194  *
195  *  The function allocates snd_card instance via kzalloc with the given
196  *  space for the driver to use freely.  The allocated struct is stored
197  *  in the given card_ret pointer.
198  *
199  *  Return: Zero if successful or a negative error code.
200  */
201 int snd_card_new(struct device *parent, int idx, const char *xid,
202                     struct module *module, int extra_size,
203                     struct snd_card **card_ret)
204 {
205         struct snd_card *card;
206         int err;
207 
208         if (snd_BUG_ON(!card_ret))
209                 return -EINVAL;
210         *card_ret = NULL;
211 
212         if (extra_size < 0)
213                 extra_size = 0;
214         card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
215         if (!card)
216                 return -ENOMEM;
217         if (extra_size > 0)
218                 card->private_data = (char *)card + sizeof(struct snd_card);
219         if (xid)
220                 strlcpy(card->id, xid, sizeof(card->id));
221         err = 0;
222         mutex_lock(&snd_card_mutex);
223         if (idx < 0) /* first check the matching module-name slot */
224                 idx = get_slot_from_bitmask(idx, module_slot_match, module);
225         if (idx < 0) /* if not matched, assign an empty slot */
226                 idx = get_slot_from_bitmask(idx, check_empty_slot, module);
227         if (idx < 0)
228                 err = -ENODEV;
229         else if (idx < snd_ecards_limit) {
230                 if (test_bit(idx, snd_cards_lock))
231                         err = -EBUSY;   /* invalid */
232         } else if (idx >= SNDRV_CARDS)
233                 err = -ENODEV;
234         if (err < 0) {
235                 mutex_unlock(&snd_card_mutex);
236                 dev_err(parent, "cannot find the slot for index %d (range 0-%i), error: %d\n",
237                          idx, snd_ecards_limit - 1, err);
238                 kfree(card);
239                 return err;
240         }
241         set_bit(idx, snd_cards_lock);           /* lock it */
242         if (idx >= snd_ecards_limit)
243                 snd_ecards_limit = idx + 1; /* increase the limit */
244         mutex_unlock(&snd_card_mutex);
245         card->dev = parent;
246         card->number = idx;
247         card->module = module;
248         INIT_LIST_HEAD(&card->devices);
249         init_rwsem(&card->controls_rwsem);
250         rwlock_init(&card->ctl_files_rwlock);
251         mutex_init(&card->user_ctl_lock);
252         INIT_LIST_HEAD(&card->controls);
253         INIT_LIST_HEAD(&card->ctl_files);
254         spin_lock_init(&card->files_lock);
255         INIT_LIST_HEAD(&card->files_list);
256 #ifdef CONFIG_PM
257         mutex_init(&card->power_lock);
258         init_waitqueue_head(&card->power_sleep);
259 #endif
260 
261         device_initialize(&card->card_dev);
262         card->card_dev.parent = parent;
263         card->card_dev.class = sound_class;
264         card->card_dev.release = release_card_device;
265         card->card_dev.groups = card->dev_groups;
266         card->dev_groups[0] = &card_dev_attr_group;
267         err = kobject_set_name(&card->card_dev.kobj, "card%d", idx);
268         if (err < 0)
269                 goto __error;
270 
271         snprintf(card->irq_descr, sizeof(card->irq_descr), "%s:%s",
272                  dev_driver_string(card->dev), dev_name(&card->card_dev));
273 
274         /* the control interface cannot be accessed from the user space until */
275         /* snd_cards_bitmask and snd_cards are set with snd_card_register */
276         err = snd_ctl_create(card);
277         if (err < 0) {
278                 dev_err(parent, "unable to register control minors\n");
279                 goto __error;
280         }
281         err = snd_info_card_create(card);
282         if (err < 0) {
283                 dev_err(parent, "unable to create card info\n");
284                 goto __error_ctl;
285         }
286         *card_ret = card;
287         return 0;
288 
289       __error_ctl:
290         snd_device_free_all(card);
291       __error:
292         put_device(&card->card_dev);
293         return err;
294 }
295 EXPORT_SYMBOL(snd_card_new);
296 
297 /* return non-zero if a card is already locked */
298 int snd_card_locked(int card)
299 {
300         int locked;
301 
302         mutex_lock(&snd_card_mutex);
303         locked = test_bit(card, snd_cards_lock);
304         mutex_unlock(&snd_card_mutex);
305         return locked;
306 }
307 
308 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
309 {
310         return -ENODEV;
311 }
312 
313 static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
314                                    size_t count, loff_t *offset)
315 {
316         return -ENODEV;
317 }
318 
319 static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
320                                     size_t count, loff_t *offset)
321 {
322         return -ENODEV;
323 }
324 
325 static int snd_disconnect_release(struct inode *inode, struct file *file)
326 {
327         struct snd_monitor_file *df = NULL, *_df;
328 
329         spin_lock(&shutdown_lock);
330         list_for_each_entry(_df, &shutdown_files, shutdown_list) {
331                 if (_df->file == file) {
332                         df = _df;
333                         list_del_init(&df->shutdown_list);
334                         break;
335                 }
336         }
337         spin_unlock(&shutdown_lock);
338 
339         if (likely(df)) {
340                 if ((file->f_flags & FASYNC) && df->disconnected_f_op->fasync)
341                         df->disconnected_f_op->fasync(-1, file, 0);
342                 return df->disconnected_f_op->release(inode, file);
343         }
344 
345         panic("%s(%p, %p) failed!", __func__, inode, file);
346 }
347 
348 static unsigned int snd_disconnect_poll(struct file * file, poll_table * wait)
349 {
350         return POLLERR | POLLNVAL;
351 }
352 
353 static long snd_disconnect_ioctl(struct file *file,
354                                  unsigned int cmd, unsigned long arg)
355 {
356         return -ENODEV;
357 }
358 
359 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
360 {
361         return -ENODEV;
362 }
363 
364 static int snd_disconnect_fasync(int fd, struct file *file, int on)
365 {
366         return -ENODEV;
367 }
368 
369 static const struct file_operations snd_shutdown_f_ops =
370 {
371         .owner =        THIS_MODULE,
372         .llseek =       snd_disconnect_llseek,
373         .read =         snd_disconnect_read,
374         .write =        snd_disconnect_write,
375         .release =      snd_disconnect_release,
376         .poll =         snd_disconnect_poll,
377         .unlocked_ioctl = snd_disconnect_ioctl,
378 #ifdef CONFIG_COMPAT
379         .compat_ioctl = snd_disconnect_ioctl,
380 #endif
381         .mmap =         snd_disconnect_mmap,
382         .fasync =       snd_disconnect_fasync
383 };
384 
385 /**
386  *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
387  *  @card: soundcard structure
388  *
389  *  Disconnects all APIs from the file-operations (user space).
390  *
391  *  Return: Zero, otherwise a negative error code.
392  *
393  *  Note: The current implementation replaces all active file->f_op with special
394  *        dummy file operations (they do nothing except release).
395  */
396 int snd_card_disconnect(struct snd_card *card)
397 {
398         struct snd_monitor_file *mfile;
399 
400         if (!card)
401                 return -EINVAL;
402 
403         spin_lock(&card->files_lock);
404         if (card->shutdown) {
405                 spin_unlock(&card->files_lock);
406                 return 0;
407         }
408         card->shutdown = 1;
409         spin_unlock(&card->files_lock);
410 
411         /* phase 1: disable fops (user space) operations for ALSA API */
412         mutex_lock(&snd_card_mutex);
413         snd_cards[card->number] = NULL;
414         clear_bit(card->number, snd_cards_lock);
415         mutex_unlock(&snd_card_mutex);
416         
417         /* phase 2: replace file->f_op with special dummy operations */
418         
419         spin_lock(&card->files_lock);
420         list_for_each_entry(mfile, &card->files_list, list) {
421                 /* it's critical part, use endless loop */
422                 /* we have no room to fail */
423                 mfile->disconnected_f_op = mfile->file->f_op;
424 
425                 spin_lock(&shutdown_lock);
426                 list_add(&mfile->shutdown_list, &shutdown_files);
427                 spin_unlock(&shutdown_lock);
428 
429                 mfile->file->f_op = &snd_shutdown_f_ops;
430                 fops_get(mfile->file->f_op);
431         }
432         spin_unlock(&card->files_lock); 
433 
434         /* phase 3: notify all connected devices about disconnection */
435         /* at this point, they cannot respond to any calls except release() */
436 
437 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
438         if (snd_mixer_oss_notify_callback)
439                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
440 #endif
441 
442         /* notify all devices that we are disconnected */
443         snd_device_disconnect_all(card);
444 
445         snd_info_card_disconnect(card);
446         if (card->registered) {
447                 device_del(&card->card_dev);
448                 card->registered = false;
449         }
450 #ifdef CONFIG_PM
451         wake_up(&card->power_sleep);
452 #endif
453         return 0;       
454 }
455 
456 EXPORT_SYMBOL(snd_card_disconnect);
457 
458 static int snd_card_do_free(struct snd_card *card)
459 {
460 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
461         if (snd_mixer_oss_notify_callback)
462                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
463 #endif
464         snd_device_free_all(card);
465         if (card->private_free)
466                 card->private_free(card);
467         snd_info_free_entry(card->proc_id);
468         if (snd_info_card_free(card) < 0) {
469                 dev_warn(card->dev, "unable to free card info\n");
470                 /* Not fatal error */
471         }
472         if (card->release_completion)
473                 complete(card->release_completion);
474         kfree(card);
475         return 0;
476 }
477 
478 /**
479  * snd_card_free_when_closed - Disconnect the card, free it later eventually
480  * @card: soundcard structure
481  *
482  * Unlike snd_card_free(), this function doesn't try to release the card
483  * resource immediately, but tries to disconnect at first.  When the card
484  * is still in use, the function returns before freeing the resources.
485  * The card resources will be freed when the refcount gets to zero.
486  */
487 int snd_card_free_when_closed(struct snd_card *card)
488 {
489         int ret = snd_card_disconnect(card);
490         if (ret)
491                 return ret;
492         put_device(&card->card_dev);
493         return 0;
494 }
495 EXPORT_SYMBOL(snd_card_free_when_closed);
496 
497 /**
498  * snd_card_free - frees given soundcard structure
499  * @card: soundcard structure
500  *
501  * This function releases the soundcard structure and the all assigned
502  * devices automatically.  That is, you don't have to release the devices
503  * by yourself.
504  *
505  * This function waits until the all resources are properly released.
506  *
507  * Return: Zero. Frees all associated devices and frees the control
508  * interface associated to given soundcard.
509  */
510 int snd_card_free(struct snd_card *card)
511 {
512         struct completion released;
513         int ret;
514 
515         init_completion(&released);
516         card->release_completion = &released;
517         ret = snd_card_free_when_closed(card);
518         if (ret)
519                 return ret;
520         /* wait, until all devices are ready for the free operation */
521         wait_for_completion(&released);
522         return 0;
523 }
524 EXPORT_SYMBOL(snd_card_free);
525 
526 /* retrieve the last word of shortname or longname */
527 static const char *retrieve_id_from_card_name(const char *name)
528 {
529         const char *spos = name;
530 
531         while (*name) {
532                 if (isspace(*name) && isalnum(name[1]))
533                         spos = name + 1;
534                 name++;
535         }
536         return spos;
537 }
538 
539 /* return true if the given id string doesn't conflict any other card ids */
540 static bool card_id_ok(struct snd_card *card, const char *id)
541 {
542         int i;
543         if (!snd_info_check_reserved_words(id))
544                 return false;
545         for (i = 0; i < snd_ecards_limit; i++) {
546                 if (snd_cards[i] && snd_cards[i] != card &&
547                     !strcmp(snd_cards[i]->id, id))
548                         return false;
549         }
550         return true;
551 }
552 
553 /* copy to card->id only with valid letters from nid */
554 static void copy_valid_id_string(struct snd_card *card, const char *src,
555                                  const char *nid)
556 {
557         char *id = card->id;
558 
559         while (*nid && !isalnum(*nid))
560                 nid++;
561         if (isdigit(*nid))
562                 *id++ = isalpha(*src) ? *src : 'D';
563         while (*nid && (size_t)(id - card->id) < sizeof(card->id) - 1) {
564                 if (isalnum(*nid))
565                         *id++ = *nid;
566                 nid++;
567         }
568         *id = 0;
569 }
570 
571 /* Set card->id from the given string
572  * If the string conflicts with other ids, add a suffix to make it unique.
573  */
574 static void snd_card_set_id_no_lock(struct snd_card *card, const char *src,
575                                     const char *nid)
576 {
577         int len, loops;
578         bool is_default = false;
579         char *id;
580         
581         copy_valid_id_string(card, src, nid);
582         id = card->id;
583 
584  again:
585         /* use "Default" for obviously invalid strings
586          * ("card" conflicts with proc directories)
587          */
588         if (!*id || !strncmp(id, "card", 4)) {
589                 strcpy(id, "Default");
590                 is_default = true;
591         }
592 
593         len = strlen(id);
594         for (loops = 0; loops < SNDRV_CARDS; loops++) {
595                 char *spos;
596                 char sfxstr[5]; /* "_012" */
597                 int sfxlen;
598 
599                 if (card_id_ok(card, id))
600                         return; /* OK */
601 
602                 /* Add _XYZ suffix */
603                 sprintf(sfxstr, "_%X", loops + 1);
604                 sfxlen = strlen(sfxstr);
605                 if (len + sfxlen >= sizeof(card->id))
606                         spos = id + sizeof(card->id) - sfxlen - 1;
607                 else
608                         spos = id + len;
609                 strcpy(spos, sfxstr);
610         }
611         /* fallback to the default id */
612         if (!is_default) {
613                 *id = 0;
614                 goto again;
615         }
616         /* last resort... */
617         dev_err(card->dev, "unable to set card id (%s)\n", id);
618         if (card->proc_root->name)
619                 strlcpy(card->id, card->proc_root->name, sizeof(card->id));
620 }
621 
622 /**
623  *  snd_card_set_id - set card identification name
624  *  @card: soundcard structure
625  *  @nid: new identification string
626  *
627  *  This function sets the card identification and checks for name
628  *  collisions.
629  */
630 void snd_card_set_id(struct snd_card *card, const char *nid)
631 {
632         /* check if user specified own card->id */
633         if (card->id[0] != '\0')
634                 return;
635         mutex_lock(&snd_card_mutex);
636         snd_card_set_id_no_lock(card, nid, nid);
637         mutex_unlock(&snd_card_mutex);
638 }
639 EXPORT_SYMBOL(snd_card_set_id);
640 
641 static ssize_t
642 card_id_show_attr(struct device *dev,
643                   struct device_attribute *attr, char *buf)
644 {
645         struct snd_card *card = container_of(dev, struct snd_card, card_dev);
646         return snprintf(buf, PAGE_SIZE, "%s\n", card->id);
647 }
648 
649 static ssize_t
650 card_id_store_attr(struct device *dev, struct device_attribute *attr,
651                    const char *buf, size_t count)
652 {
653         struct snd_card *card = container_of(dev, struct snd_card, card_dev);
654         char buf1[sizeof(card->id)];
655         size_t copy = count > sizeof(card->id) - 1 ?
656                                         sizeof(card->id) - 1 : count;
657         size_t idx;
658         int c;
659 
660         for (idx = 0; idx < copy; idx++) {
661                 c = buf[idx];
662                 if (!isalnum(c) && c != '_' && c != '-')
663                         return -EINVAL;
664         }
665         memcpy(buf1, buf, copy);
666         buf1[copy] = '\0';
667         mutex_lock(&snd_card_mutex);
668         if (!card_id_ok(NULL, buf1)) {
669                 mutex_unlock(&snd_card_mutex);
670                 return -EEXIST;
671         }
672         strcpy(card->id, buf1);
673         snd_info_card_id_change(card);
674         mutex_unlock(&snd_card_mutex);
675 
676         return count;
677 }
678 
679 static DEVICE_ATTR(id, S_IRUGO | S_IWUSR, card_id_show_attr, card_id_store_attr);
680 
681 static ssize_t
682 card_number_show_attr(struct device *dev,
683                      struct device_attribute *attr, char *buf)
684 {
685         struct snd_card *card = container_of(dev, struct snd_card, card_dev);
686         return snprintf(buf, PAGE_SIZE, "%i\n", card->number);
687 }
688 
689 static DEVICE_ATTR(number, S_IRUGO, card_number_show_attr, NULL);
690 
691 static struct attribute *card_dev_attrs[] = {
692         &dev_attr_id.attr,
693         &dev_attr_number.attr,
694         NULL
695 };
696 
697 static const struct attribute_group card_dev_attr_group = {
698         .attrs  = card_dev_attrs,
699 };
700 
701 /**
702  * snd_card_add_dev_attr - Append a new sysfs attribute group to card
703  * @card: card instance
704  * @group: attribute group to append
705  */
706 int snd_card_add_dev_attr(struct snd_card *card,
707                           const struct attribute_group *group)
708 {
709         int i;
710 
711         /* loop for (arraysize-1) here to keep NULL at the last entry */
712         for (i = 0; i < ARRAY_SIZE(card->dev_groups) - 1; i++) {
713                 if (!card->dev_groups[i]) {
714                         card->dev_groups[i] = group;
715                         return 0;
716                 }
717         }
718 
719         dev_err(card->dev, "Too many groups assigned\n");
720         return -ENOSPC;
721 };
722 EXPORT_SYMBOL_GPL(snd_card_add_dev_attr);
723 
724 /**
725  *  snd_card_register - register the soundcard
726  *  @card: soundcard structure
727  *
728  *  This function registers all the devices assigned to the soundcard.
729  *  Until calling this, the ALSA control interface is blocked from the
730  *  external accesses.  Thus, you should call this function at the end
731  *  of the initialization of the card.
732  *
733  *  Return: Zero otherwise a negative error code if the registration failed.
734  */
735 int snd_card_register(struct snd_card *card)
736 {
737         int err;
738 
739         if (snd_BUG_ON(!card))
740                 return -EINVAL;
741 
742         if (!card->registered) {
743                 err = device_add(&card->card_dev);
744                 if (err < 0)
745                         return err;
746                 card->registered = true;
747         }
748 
749         if ((err = snd_device_register_all(card)) < 0)
750                 return err;
751         mutex_lock(&snd_card_mutex);
752         if (snd_cards[card->number]) {
753                 /* already registered */
754                 mutex_unlock(&snd_card_mutex);
755                 return snd_info_card_register(card); /* register pending info */
756         }
757         if (*card->id) {
758                 /* make a unique id name from the given string */
759                 char tmpid[sizeof(card->id)];
760                 memcpy(tmpid, card->id, sizeof(card->id));
761                 snd_card_set_id_no_lock(card, tmpid, tmpid);
762         } else {
763                 /* create an id from either shortname or longname */
764                 const char *src;
765                 src = *card->shortname ? card->shortname : card->longname;
766                 snd_card_set_id_no_lock(card, src,
767                                         retrieve_id_from_card_name(src));
768         }
769         snd_cards[card->number] = card;
770         mutex_unlock(&snd_card_mutex);
771         init_info_for_card(card);
772 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
773         if (snd_mixer_oss_notify_callback)
774                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
775 #endif
776         return 0;
777 }
778 
779 EXPORT_SYMBOL(snd_card_register);
780 
781 #ifdef CONFIG_SND_PROC_FS
782 static void snd_card_info_read(struct snd_info_entry *entry,
783                                struct snd_info_buffer *buffer)
784 {
785         int idx, count;
786         struct snd_card *card;
787 
788         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
789                 mutex_lock(&snd_card_mutex);
790                 if ((card = snd_cards[idx]) != NULL) {
791                         count++;
792                         snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
793                                         idx,
794                                         card->id,
795                                         card->driver,
796                                         card->shortname);
797                         snd_iprintf(buffer, "                      %s\n",
798                                         card->longname);
799                 }
800                 mutex_unlock(&snd_card_mutex);
801         }
802         if (!count)
803                 snd_iprintf(buffer, "--- no soundcards ---\n");
804 }
805 
806 #ifdef CONFIG_SND_OSSEMUL
807 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
808 {
809         int idx, count;
810         struct snd_card *card;
811 
812         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
813                 mutex_lock(&snd_card_mutex);
814                 if ((card = snd_cards[idx]) != NULL) {
815                         count++;
816                         snd_iprintf(buffer, "%s\n", card->longname);
817                 }
818                 mutex_unlock(&snd_card_mutex);
819         }
820         if (!count) {
821                 snd_iprintf(buffer, "--- no soundcards ---\n");
822         }
823 }
824 
825 #endif
826 
827 #ifdef MODULE
828 static void snd_card_module_info_read(struct snd_info_entry *entry,
829                                       struct snd_info_buffer *buffer)
830 {
831         int idx;
832         struct snd_card *card;
833 
834         for (idx = 0; idx < SNDRV_CARDS; idx++) {
835                 mutex_lock(&snd_card_mutex);
836                 if ((card = snd_cards[idx]) != NULL)
837                         snd_iprintf(buffer, "%2i %s\n",
838                                     idx, card->module->name);
839                 mutex_unlock(&snd_card_mutex);
840         }
841 }
842 #endif
843 
844 int __init snd_card_info_init(void)
845 {
846         struct snd_info_entry *entry;
847 
848         entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
849         if (! entry)
850                 return -ENOMEM;
851         entry->c.text.read = snd_card_info_read;
852         if (snd_info_register(entry) < 0)
853                 return -ENOMEM; /* freed in error path */
854 
855 #ifdef MODULE
856         entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
857         if (!entry)
858                 return -ENOMEM;
859         entry->c.text.read = snd_card_module_info_read;
860         if (snd_info_register(entry) < 0)
861                 return -ENOMEM; /* freed in error path */
862 #endif
863 
864         return 0;
865 }
866 #endif /* CONFIG_SND_PROC_FS */
867 
868 /**
869  *  snd_component_add - add a component string
870  *  @card: soundcard structure
871  *  @component: the component id string
872  *
873  *  This function adds the component id string to the supported list.
874  *  The component can be referred from the alsa-lib.
875  *
876  *  Return: Zero otherwise a negative error code.
877  */
878   
879 int snd_component_add(struct snd_card *card, const char *component)
880 {
881         char *ptr;
882         int len = strlen(component);
883 
884         ptr = strstr(card->components, component);
885         if (ptr != NULL) {
886                 if (ptr[len] == '\0' || ptr[len] == ' ')        /* already there */
887                         return 1;
888         }
889         if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
890                 snd_BUG();
891                 return -ENOMEM;
892         }
893         if (card->components[0] != '\0')
894                 strcat(card->components, " ");
895         strcat(card->components, component);
896         return 0;
897 }
898 
899 EXPORT_SYMBOL(snd_component_add);
900 
901 /**
902  *  snd_card_file_add - add the file to the file list of the card
903  *  @card: soundcard structure
904  *  @file: file pointer
905  *
906  *  This function adds the file to the file linked-list of the card.
907  *  This linked-list is used to keep tracking the connection state,
908  *  and to avoid the release of busy resources by hotplug.
909  *
910  *  Return: zero or a negative error code.
911  */
912 int snd_card_file_add(struct snd_card *card, struct file *file)
913 {
914         struct snd_monitor_file *mfile;
915 
916         mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
917         if (mfile == NULL)
918                 return -ENOMEM;
919         mfile->file = file;
920         mfile->disconnected_f_op = NULL;
921         INIT_LIST_HEAD(&mfile->shutdown_list);
922         spin_lock(&card->files_lock);
923         if (card->shutdown) {
924                 spin_unlock(&card->files_lock);
925                 kfree(mfile);
926                 return -ENODEV;
927         }
928         list_add(&mfile->list, &card->files_list);
929         get_device(&card->card_dev);
930         spin_unlock(&card->files_lock);
931         return 0;
932 }
933 
934 EXPORT_SYMBOL(snd_card_file_add);
935 
936 /**
937  *  snd_card_file_remove - remove the file from the file list
938  *  @card: soundcard structure
939  *  @file: file pointer
940  *
941  *  This function removes the file formerly added to the card via
942  *  snd_card_file_add() function.
943  *  If all files are removed and snd_card_free_when_closed() was
944  *  called beforehand, it processes the pending release of
945  *  resources.
946  *
947  *  Return: Zero or a negative error code.
948  */
949 int snd_card_file_remove(struct snd_card *card, struct file *file)
950 {
951         struct snd_monitor_file *mfile, *found = NULL;
952 
953         spin_lock(&card->files_lock);
954         list_for_each_entry(mfile, &card->files_list, list) {
955                 if (mfile->file == file) {
956                         list_del(&mfile->list);
957                         spin_lock(&shutdown_lock);
958                         list_del(&mfile->shutdown_list);
959                         spin_unlock(&shutdown_lock);
960                         if (mfile->disconnected_f_op)
961                                 fops_put(mfile->disconnected_f_op);
962                         found = mfile;
963                         break;
964                 }
965         }
966         spin_unlock(&card->files_lock);
967         if (!found) {
968                 dev_err(card->dev, "card file remove problem (%p)\n", file);
969                 return -ENOENT;
970         }
971         kfree(found);
972         put_device(&card->card_dev);
973         return 0;
974 }
975 
976 EXPORT_SYMBOL(snd_card_file_remove);
977 
978 #ifdef CONFIG_PM
979 /**
980  *  snd_power_wait - wait until the power-state is changed.
981  *  @card: soundcard structure
982  *  @power_state: expected power state
983  *
984  *  Waits until the power-state is changed.
985  *
986  *  Return: Zero if successful, or a negative error code.
987  *
988  *  Note: the power lock must be active before call.
989  */
990 int snd_power_wait(struct snd_card *card, unsigned int power_state)
991 {
992         wait_queue_t wait;
993         int result = 0;
994 
995         /* fastpath */
996         if (snd_power_get_state(card) == power_state)
997                 return 0;
998         init_waitqueue_entry(&wait, current);
999         add_wait_queue(&card->power_sleep, &wait);
1000         while (1) {
1001                 if (card->shutdown) {
1002                         result = -ENODEV;
1003                         break;
1004                 }
1005                 if (snd_power_get_state(card) == power_state)
1006                         break;
1007                 set_current_state(TASK_UNINTERRUPTIBLE);
1008                 snd_power_unlock(card);
1009                 schedule_timeout(30 * HZ);
1010                 snd_power_lock(card);
1011         }
1012         remove_wait_queue(&card->power_sleep, &wait);
1013         return result;
1014 }
1015 
1016 EXPORT_SYMBOL(snd_power_wait);
1017 #endif /* CONFIG_PM */
1018 

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