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

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  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /*
  3  *  Initialization routines
  4  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
  5  */
  6 
  7 #include <linux/init.h>
  8 #include <linux/sched.h>
  9 #include <linux/module.h>
 10 #include <linux/device.h>
 11 #include <linux/file.h>
 12 #include <linux/slab.h>
 13 #include <linux/time.h>
 14 #include <linux/ctype.h>
 15 #include <linux/pm.h>
 16 #include <linux/completion.h>
 17 
 18 #include <sound/core.h>
 19 #include <sound/control.h>
 20 #include <sound/info.h>
 21 
 22 /* monitor files for graceful shutdown (hotplug) */
 23 struct snd_monitor_file {
 24         struct file *file;
 25         const struct file_operations *disconnected_f_op;
 26         struct list_head shutdown_list; /* still need to shutdown */
 27         struct list_head list;  /* link of monitor files */
 28 };
 29 
 30 static DEFINE_SPINLOCK(shutdown_lock);
 31 static LIST_HEAD(shutdown_files);
 32 
 33 static const struct file_operations snd_shutdown_f_ops;
 34 
 35 /* locked for registering/using */
 36 static DECLARE_BITMAP(snd_cards_lock, SNDRV_CARDS);
 37 static struct snd_card *snd_cards[SNDRV_CARDS];
 38 
 39 static DEFINE_MUTEX(snd_card_mutex);
 40 
 41 static char *slots[SNDRV_CARDS];
 42 module_param_array(slots, charp, NULL, 0444);
 43 MODULE_PARM_DESC(slots, "Module names assigned to the slots.");
 44 
 45 /* return non-zero if the given index is reserved for the given
 46  * module via slots option
 47  */
 48 static int module_slot_match(struct module *module, int idx)
 49 {
 50         int match = 1;
 51 #ifdef MODULE
 52         const char *s1, *s2;
 53 
 54         if (!module || !*module->name || !slots[idx])
 55                 return 0;
 56 
 57         s1 = module->name;
 58         s2 = slots[idx];
 59         if (*s2 == '!') {
 60                 match = 0; /* negative match */
 61                 s2++;
 62         }
 63         /* compare module name strings
 64          * hyphens are handled as equivalent with underscore
 65          */
 66         for (;;) {
 67                 char c1 = *s1++;
 68                 char c2 = *s2++;
 69                 if (c1 == '-')
 70                         c1 = '_';
 71                 if (c2 == '-')
 72                         c2 = '_';
 73                 if (c1 != c2)
 74                         return !match;
 75                 if (!c1)
 76                         break;
 77         }
 78 #endif /* MODULE */
 79         return match;
 80 }
 81 
 82 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 83 int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
 84 EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
 85 #endif
 86 
 87 static int check_empty_slot(struct module *module, int slot)
 88 {
 89         return !slots[slot] || !*slots[slot];
 90 }
 91 
 92 /* return an empty slot number (>= 0) found in the given bitmask @mask.
 93  * @mask == -1 == 0xffffffff means: take any free slot up to 32
 94  * when no slot is available, return the original @mask as is.
 95  */
 96 static int get_slot_from_bitmask(int mask, int (*check)(struct module *, int),
 97                                  struct module *module)
 98 {
 99         int slot;
100 
101         for (slot = 0; slot < SNDRV_CARDS; slot++) {
102                 if (slot < 32 && !(mask & (1U << slot)))
103                         continue;
104                 if (!test_bit(slot, snd_cards_lock)) {
105                         if (check(module, slot))
106                                 return slot; /* found */
107                 }
108         }
109         return mask; /* unchanged */
110 }
111 
112 /* the default release callback set in snd_device_initialize() below;
113  * this is just NOP for now, as almost all jobs are already done in
114  * dev_free callback of snd_device chain instead.
115  */
116 static void default_release(struct device *dev)
117 {
118 }
119 
120 /**
121  * snd_device_initialize - Initialize struct device for sound devices
122  * @dev: device to initialize
123  * @card: card to assign, optional
124  */
125 void snd_device_initialize(struct device *dev, struct snd_card *card)
126 {
127         device_initialize(dev);
128         if (card)
129                 dev->parent = &card->card_dev;
130         dev->class = sound_class;
131         dev->release = default_release;
132 }
133 EXPORT_SYMBOL_GPL(snd_device_initialize);
134 
135 static int snd_card_do_free(struct snd_card *card);
136 static const struct attribute_group card_dev_attr_group;
137 
138 static void release_card_device(struct device *dev)
139 {
140         snd_card_do_free(dev_to_snd_card(dev));
141 }
142 
143 /**
144  *  snd_card_new - create and initialize a soundcard structure
145  *  @parent: the parent device object
146  *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
147  *  @xid: card identification (ASCII string)
148  *  @module: top level module for locking
149  *  @extra_size: allocate this extra size after the main soundcard structure
150  *  @card_ret: the pointer to store the created card instance
151  *
152  *  Creates and initializes a soundcard structure.
153  *
154  *  The function allocates snd_card instance via kzalloc with the given
155  *  space for the driver to use freely.  The allocated struct is stored
156  *  in the given card_ret pointer.
157  *
158  *  Return: Zero if successful or a negative error code.
159  */
160 int snd_card_new(struct device *parent, int idx, const char *xid,
161                     struct module *module, int extra_size,
162                     struct snd_card **card_ret)
163 {
164         struct snd_card *card;
165         int err;
166 
167         if (snd_BUG_ON(!card_ret))
168                 return -EINVAL;
169         *card_ret = NULL;
170 
171         if (extra_size < 0)
172                 extra_size = 0;
173         card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
174         if (!card)
175                 return -ENOMEM;
176         if (extra_size > 0)
177                 card->private_data = (char *)card + sizeof(struct snd_card);
178         if (xid)
179                 strlcpy(card->id, xid, sizeof(card->id));
180         err = 0;
181         mutex_lock(&snd_card_mutex);
182         if (idx < 0) /* first check the matching module-name slot */
183                 idx = get_slot_from_bitmask(idx, module_slot_match, module);
184         if (idx < 0) /* if not matched, assign an empty slot */
185                 idx = get_slot_from_bitmask(idx, check_empty_slot, module);
186         if (idx < 0)
187                 err = -ENODEV;
188         else if (idx < snd_ecards_limit) {
189                 if (test_bit(idx, snd_cards_lock))
190                         err = -EBUSY;   /* invalid */
191         } else if (idx >= SNDRV_CARDS)
192                 err = -ENODEV;
193         if (err < 0) {
194                 mutex_unlock(&snd_card_mutex);
195                 dev_err(parent, "cannot find the slot for index %d (range 0-%i), error: %d\n",
196                          idx, snd_ecards_limit - 1, err);
197                 kfree(card);
198                 return err;
199         }
200         set_bit(idx, snd_cards_lock);           /* lock it */
201         if (idx >= snd_ecards_limit)
202                 snd_ecards_limit = idx + 1; /* increase the limit */
203         mutex_unlock(&snd_card_mutex);
204         card->dev = parent;
205         card->number = idx;
206         card->module = module;
207         INIT_LIST_HEAD(&card->devices);
208         init_rwsem(&card->controls_rwsem);
209         rwlock_init(&card->ctl_files_rwlock);
210         INIT_LIST_HEAD(&card->controls);
211         INIT_LIST_HEAD(&card->ctl_files);
212         spin_lock_init(&card->files_lock);
213         INIT_LIST_HEAD(&card->files_list);
214 #ifdef CONFIG_PM
215         init_waitqueue_head(&card->power_sleep);
216 #endif
217         init_waitqueue_head(&card->remove_sleep);
218 
219         device_initialize(&card->card_dev);
220         card->card_dev.parent = parent;
221         card->card_dev.class = sound_class;
222         card->card_dev.release = release_card_device;
223         card->card_dev.groups = card->dev_groups;
224         card->dev_groups[0] = &card_dev_attr_group;
225         err = kobject_set_name(&card->card_dev.kobj, "card%d", idx);
226         if (err < 0)
227                 goto __error;
228 
229         snprintf(card->irq_descr, sizeof(card->irq_descr), "%s:%s",
230                  dev_driver_string(card->dev), dev_name(&card->card_dev));
231 
232         /* the control interface cannot be accessed from the user space until */
233         /* snd_cards_bitmask and snd_cards are set with snd_card_register */
234         err = snd_ctl_create(card);
235         if (err < 0) {
236                 dev_err(parent, "unable to register control minors\n");
237                 goto __error;
238         }
239         err = snd_info_card_create(card);
240         if (err < 0) {
241                 dev_err(parent, "unable to create card info\n");
242                 goto __error_ctl;
243         }
244         *card_ret = card;
245         return 0;
246 
247       __error_ctl:
248         snd_device_free_all(card);
249       __error:
250         put_device(&card->card_dev);
251         return err;
252 }
253 EXPORT_SYMBOL(snd_card_new);
254 
255 /**
256  * snd_card_ref - Get the card object from the index
257  * @idx: the card index
258  *
259  * Returns a card object corresponding to the given index or NULL if not found.
260  * Release the object via snd_card_unref().
261  */
262 struct snd_card *snd_card_ref(int idx)
263 {
264         struct snd_card *card;
265 
266         mutex_lock(&snd_card_mutex);
267         card = snd_cards[idx];
268         if (card)
269                 get_device(&card->card_dev);
270         mutex_unlock(&snd_card_mutex);
271         return card;
272 }
273 EXPORT_SYMBOL_GPL(snd_card_ref);
274 
275 /* return non-zero if a card is already locked */
276 int snd_card_locked(int card)
277 {
278         int locked;
279 
280         mutex_lock(&snd_card_mutex);
281         locked = test_bit(card, snd_cards_lock);
282         mutex_unlock(&snd_card_mutex);
283         return locked;
284 }
285 
286 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
287 {
288         return -ENODEV;
289 }
290 
291 static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
292                                    size_t count, loff_t *offset)
293 {
294         return -ENODEV;
295 }
296 
297 static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
298                                     size_t count, loff_t *offset)
299 {
300         return -ENODEV;
301 }
302 
303 static int snd_disconnect_release(struct inode *inode, struct file *file)
304 {
305         struct snd_monitor_file *df = NULL, *_df;
306 
307         spin_lock(&shutdown_lock);
308         list_for_each_entry(_df, &shutdown_files, shutdown_list) {
309                 if (_df->file == file) {
310                         df = _df;
311                         list_del_init(&df->shutdown_list);
312                         break;
313                 }
314         }
315         spin_unlock(&shutdown_lock);
316 
317         if (likely(df)) {
318                 if ((file->f_flags & FASYNC) && df->disconnected_f_op->fasync)
319                         df->disconnected_f_op->fasync(-1, file, 0);
320                 return df->disconnected_f_op->release(inode, file);
321         }
322 
323         panic("%s(%p, %p) failed!", __func__, inode, file);
324 }
325 
326 static __poll_t snd_disconnect_poll(struct file * file, poll_table * wait)
327 {
328         return EPOLLERR | EPOLLNVAL;
329 }
330 
331 static long snd_disconnect_ioctl(struct file *file,
332                                  unsigned int cmd, unsigned long arg)
333 {
334         return -ENODEV;
335 }
336 
337 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
338 {
339         return -ENODEV;
340 }
341 
342 static int snd_disconnect_fasync(int fd, struct file *file, int on)
343 {
344         return -ENODEV;
345 }
346 
347 static const struct file_operations snd_shutdown_f_ops =
348 {
349         .owner =        THIS_MODULE,
350         .llseek =       snd_disconnect_llseek,
351         .read =         snd_disconnect_read,
352         .write =        snd_disconnect_write,
353         .release =      snd_disconnect_release,
354         .poll =         snd_disconnect_poll,
355         .unlocked_ioctl = snd_disconnect_ioctl,
356 #ifdef CONFIG_COMPAT
357         .compat_ioctl = snd_disconnect_ioctl,
358 #endif
359         .mmap =         snd_disconnect_mmap,
360         .fasync =       snd_disconnect_fasync
361 };
362 
363 /**
364  *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
365  *  @card: soundcard structure
366  *
367  *  Disconnects all APIs from the file-operations (user space).
368  *
369  *  Return: Zero, otherwise a negative error code.
370  *
371  *  Note: The current implementation replaces all active file->f_op with special
372  *        dummy file operations (they do nothing except release).
373  */
374 int snd_card_disconnect(struct snd_card *card)
375 {
376         struct snd_monitor_file *mfile;
377 
378         if (!card)
379                 return -EINVAL;
380 
381         spin_lock(&card->files_lock);
382         if (card->shutdown) {
383                 spin_unlock(&card->files_lock);
384                 return 0;
385         }
386         card->shutdown = 1;
387         spin_unlock(&card->files_lock);
388 
389         /* replace file->f_op with special dummy operations */
390         spin_lock(&card->files_lock);
391         list_for_each_entry(mfile, &card->files_list, list) {
392                 /* it's critical part, use endless loop */
393                 /* we have no room to fail */
394                 mfile->disconnected_f_op = mfile->file->f_op;
395 
396                 spin_lock(&shutdown_lock);
397                 list_add(&mfile->shutdown_list, &shutdown_files);
398                 spin_unlock(&shutdown_lock);
399 
400                 mfile->file->f_op = &snd_shutdown_f_ops;
401                 fops_get(mfile->file->f_op);
402         }
403         spin_unlock(&card->files_lock); 
404 
405         /* notify all connected devices about disconnection */
406         /* at this point, they cannot respond to any calls except release() */
407 
408 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
409         if (snd_mixer_oss_notify_callback)
410                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
411 #endif
412 
413         /* notify all devices that we are disconnected */
414         snd_device_disconnect_all(card);
415 
416         snd_info_card_disconnect(card);
417         if (card->registered) {
418                 device_del(&card->card_dev);
419                 card->registered = false;
420         }
421 
422         /* disable fops (user space) operations for ALSA API */
423         mutex_lock(&snd_card_mutex);
424         snd_cards[card->number] = NULL;
425         clear_bit(card->number, snd_cards_lock);
426         mutex_unlock(&snd_card_mutex);
427 
428 #ifdef CONFIG_PM
429         wake_up(&card->power_sleep);
430 #endif
431         return 0;       
432 }
433 EXPORT_SYMBOL(snd_card_disconnect);
434 
435 /**
436  * snd_card_disconnect_sync - disconnect card and wait until files get closed
437  * @card: card object to disconnect
438  *
439  * This calls snd_card_disconnect() for disconnecting all belonging components
440  * and waits until all pending files get closed.
441  * It assures that all accesses from user-space finished so that the driver
442  * can release its resources gracefully.
443  */
444 void snd_card_disconnect_sync(struct snd_card *card)
445 {
446         int err;
447 
448         err = snd_card_disconnect(card);
449         if (err < 0) {
450                 dev_err(card->dev,
451                         "snd_card_disconnect error (%d), skipping sync\n",
452                         err);
453                 return;
454         }
455 
456         spin_lock_irq(&card->files_lock);
457         wait_event_lock_irq(card->remove_sleep,
458                             list_empty(&card->files_list),
459                             card->files_lock);
460         spin_unlock_irq(&card->files_lock);
461 }
462 EXPORT_SYMBOL_GPL(snd_card_disconnect_sync);
463 
464 static int snd_card_do_free(struct snd_card *card)
465 {
466 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
467         if (snd_mixer_oss_notify_callback)
468                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
469 #endif
470         snd_device_free_all(card);
471         if (card->private_free)
472                 card->private_free(card);
473         if (snd_info_card_free(card) < 0) {
474                 dev_warn(card->dev, "unable to free card info\n");
475                 /* Not fatal error */
476         }
477         if (card->release_completion)
478                 complete(card->release_completion);
479         kfree(card);
480         return 0;
481 }
482 
483 /**
484  * snd_card_free_when_closed - Disconnect the card, free it later eventually
485  * @card: soundcard structure
486  *
487  * Unlike snd_card_free(), this function doesn't try to release the card
488  * resource immediately, but tries to disconnect at first.  When the card
489  * is still in use, the function returns before freeing the resources.
490  * The card resources will be freed when the refcount gets to zero.
491  */
492 int snd_card_free_when_closed(struct snd_card *card)
493 {
494         int ret = snd_card_disconnect(card);
495         if (ret)
496                 return ret;
497         put_device(&card->card_dev);
498         return 0;
499 }
500 EXPORT_SYMBOL(snd_card_free_when_closed);
501 
502 /**
503  * snd_card_free - frees given soundcard structure
504  * @card: soundcard structure
505  *
506  * This function releases the soundcard structure and the all assigned
507  * devices automatically.  That is, you don't have to release the devices
508  * by yourself.
509  *
510  * This function waits until the all resources are properly released.
511  *
512  * Return: Zero. Frees all associated devices and frees the control
513  * interface associated to given soundcard.
514  */
515 int snd_card_free(struct snd_card *card)
516 {
517         struct completion released;
518         int ret;
519 
520         init_completion(&released);
521         card->release_completion = &released;
522         ret = snd_card_free_when_closed(card);
523         if (ret)
524                 return ret;
525         /* wait, until all devices are ready for the free operation */
526         wait_for_completion(&released);
527         return 0;
528 }
529 EXPORT_SYMBOL(snd_card_free);
530 
531 /* retrieve the last word of shortname or longname */
532 static const char *retrieve_id_from_card_name(const char *name)
533 {
534         const char *spos = name;
535 
536         while (*name) {
537                 if (isspace(*name) && isalnum(name[1]))
538                         spos = name + 1;
539                 name++;
540         }
541         return spos;
542 }
543 
544 /* return true if the given id string doesn't conflict any other card ids */
545 static bool card_id_ok(struct snd_card *card, const char *id)
546 {
547         int i;
548         if (!snd_info_check_reserved_words(id))
549                 return false;
550         for (i = 0; i < snd_ecards_limit; i++) {
551                 if (snd_cards[i] && snd_cards[i] != card &&
552                     !strcmp(snd_cards[i]->id, id))
553                         return false;
554         }
555         return true;
556 }
557 
558 /* copy to card->id only with valid letters from nid */
559 static void copy_valid_id_string(struct snd_card *card, const char *src,
560                                  const char *nid)
561 {
562         char *id = card->id;
563 
564         while (*nid && !isalnum(*nid))
565                 nid++;
566         if (isdigit(*nid))
567                 *id++ = isalpha(*src) ? *src : 'D';
568         while (*nid && (size_t)(id - card->id) < sizeof(card->id) - 1) {
569                 if (isalnum(*nid))
570                         *id++ = *nid;
571                 nid++;
572         }
573         *id = 0;
574 }
575 
576 /* Set card->id from the given string
577  * If the string conflicts with other ids, add a suffix to make it unique.
578  */
579 static void snd_card_set_id_no_lock(struct snd_card *card, const char *src,
580                                     const char *nid)
581 {
582         int len, loops;
583         bool is_default = false;
584         char *id;
585         
586         copy_valid_id_string(card, src, nid);
587         id = card->id;
588 
589  again:
590         /* use "Default" for obviously invalid strings
591          * ("card" conflicts with proc directories)
592          */
593         if (!*id || !strncmp(id, "card", 4)) {
594                 strcpy(id, "Default");
595                 is_default = true;
596         }
597 
598         len = strlen(id);
599         for (loops = 0; loops < SNDRV_CARDS; loops++) {
600                 char *spos;
601                 char sfxstr[5]; /* "_012" */
602                 int sfxlen;
603 
604                 if (card_id_ok(card, id))
605                         return; /* OK */
606 
607                 /* Add _XYZ suffix */
608                 sprintf(sfxstr, "_%X", loops + 1);
609                 sfxlen = strlen(sfxstr);
610                 if (len + sfxlen >= sizeof(card->id))
611                         spos = id + sizeof(card->id) - sfxlen - 1;
612                 else
613                         spos = id + len;
614                 strcpy(spos, sfxstr);
615         }
616         /* fallback to the default id */
617         if (!is_default) {
618                 *id = 0;
619                 goto again;
620         }
621         /* last resort... */
622         dev_err(card->dev, "unable to set card id (%s)\n", id);
623         if (card->proc_root->name)
624                 strlcpy(card->id, card->proc_root->name, sizeof(card->id));
625 }
626 
627 /**
628  *  snd_card_set_id - set card identification name
629  *  @card: soundcard structure
630  *  @nid: new identification string
631  *
632  *  This function sets the card identification and checks for name
633  *  collisions.
634  */
635 void snd_card_set_id(struct snd_card *card, const char *nid)
636 {
637         /* check if user specified own card->id */
638         if (card->id[0] != '\0')
639                 return;
640         mutex_lock(&snd_card_mutex);
641         snd_card_set_id_no_lock(card, nid, nid);
642         mutex_unlock(&snd_card_mutex);
643 }
644 EXPORT_SYMBOL(snd_card_set_id);
645 
646 static ssize_t
647 card_id_show_attr(struct device *dev,
648                   struct device_attribute *attr, char *buf)
649 {
650         struct snd_card *card = container_of(dev, struct snd_card, card_dev);
651         return scnprintf(buf, PAGE_SIZE, "%s\n", card->id);
652 }
653 
654 static ssize_t
655 card_id_store_attr(struct device *dev, struct device_attribute *attr,
656                    const char *buf, size_t count)
657 {
658         struct snd_card *card = container_of(dev, struct snd_card, card_dev);
659         char buf1[sizeof(card->id)];
660         size_t copy = count > sizeof(card->id) - 1 ?
661                                         sizeof(card->id) - 1 : count;
662         size_t idx;
663         int c;
664 
665         for (idx = 0; idx < copy; idx++) {
666                 c = buf[idx];
667                 if (!isalnum(c) && c != '_' && c != '-')
668                         return -EINVAL;
669         }
670         memcpy(buf1, buf, copy);
671         buf1[copy] = '\0';
672         mutex_lock(&snd_card_mutex);
673         if (!card_id_ok(NULL, buf1)) {
674                 mutex_unlock(&snd_card_mutex);
675                 return -EEXIST;
676         }
677         strcpy(card->id, buf1);
678         snd_info_card_id_change(card);
679         mutex_unlock(&snd_card_mutex);
680 
681         return count;
682 }
683 
684 static DEVICE_ATTR(id, 0644, card_id_show_attr, card_id_store_attr);
685 
686 static ssize_t
687 card_number_show_attr(struct device *dev,
688                      struct device_attribute *attr, char *buf)
689 {
690         struct snd_card *card = container_of(dev, struct snd_card, card_dev);
691         return scnprintf(buf, PAGE_SIZE, "%i\n", card->number);
692 }
693 
694 static DEVICE_ATTR(number, 0444, card_number_show_attr, NULL);
695 
696 static struct attribute *card_dev_attrs[] = {
697         &dev_attr_id.attr,
698         &dev_attr_number.attr,
699         NULL
700 };
701 
702 static const struct attribute_group card_dev_attr_group = {
703         .attrs  = card_dev_attrs,
704 };
705 
706 /**
707  * snd_card_add_dev_attr - Append a new sysfs attribute group to card
708  * @card: card instance
709  * @group: attribute group to append
710  */
711 int snd_card_add_dev_attr(struct snd_card *card,
712                           const struct attribute_group *group)
713 {
714         int i;
715 
716         /* loop for (arraysize-1) here to keep NULL at the last entry */
717         for (i = 0; i < ARRAY_SIZE(card->dev_groups) - 1; i++) {
718                 if (!card->dev_groups[i]) {
719                         card->dev_groups[i] = group;
720                         return 0;
721                 }
722         }
723 
724         dev_err(card->dev, "Too many groups assigned\n");
725         return -ENOSPC;
726 }
727 EXPORT_SYMBOL_GPL(snd_card_add_dev_attr);
728 
729 /**
730  *  snd_card_register - register the soundcard
731  *  @card: soundcard structure
732  *
733  *  This function registers all the devices assigned to the soundcard.
734  *  Until calling this, the ALSA control interface is blocked from the
735  *  external accesses.  Thus, you should call this function at the end
736  *  of the initialization of the card.
737  *
738  *  Return: Zero otherwise a negative error code if the registration failed.
739  */
740 int snd_card_register(struct snd_card *card)
741 {
742         int err;
743 
744         if (snd_BUG_ON(!card))
745                 return -EINVAL;
746 
747         if (!card->registered) {
748                 err = device_add(&card->card_dev);
749                 if (err < 0)
750                         return err;
751                 card->registered = true;
752         }
753 
754         if ((err = snd_device_register_all(card)) < 0)
755                 return err;
756         mutex_lock(&snd_card_mutex);
757         if (snd_cards[card->number]) {
758                 /* already registered */
759                 mutex_unlock(&snd_card_mutex);
760                 return snd_info_card_register(card); /* register pending info */
761         }
762         if (*card->id) {
763                 /* make a unique id name from the given string */
764                 char tmpid[sizeof(card->id)];
765                 memcpy(tmpid, card->id, sizeof(card->id));
766                 snd_card_set_id_no_lock(card, tmpid, tmpid);
767         } else {
768                 /* create an id from either shortname or longname */
769                 const char *src;
770                 src = *card->shortname ? card->shortname : card->longname;
771                 snd_card_set_id_no_lock(card, src,
772                                         retrieve_id_from_card_name(src));
773         }
774         snd_cards[card->number] = card;
775         mutex_unlock(&snd_card_mutex);
776         err = snd_info_card_register(card);
777         if (err < 0)
778                 return err;
779 
780 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
781         if (snd_mixer_oss_notify_callback)
782                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
783 #endif
784         return 0;
785 }
786 EXPORT_SYMBOL(snd_card_register);
787 
788 #ifdef CONFIG_SND_PROC_FS
789 static void snd_card_info_read(struct snd_info_entry *entry,
790                                struct snd_info_buffer *buffer)
791 {
792         int idx, count;
793         struct snd_card *card;
794 
795         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
796                 mutex_lock(&snd_card_mutex);
797                 if ((card = snd_cards[idx]) != NULL) {
798                         count++;
799                         snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
800                                         idx,
801                                         card->id,
802                                         card->driver,
803                                         card->shortname);
804                         snd_iprintf(buffer, "                      %s\n",
805                                         card->longname);
806                 }
807                 mutex_unlock(&snd_card_mutex);
808         }
809         if (!count)
810                 snd_iprintf(buffer, "--- no soundcards ---\n");
811 }
812 
813 #ifdef CONFIG_SND_OSSEMUL
814 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
815 {
816         int idx, count;
817         struct snd_card *card;
818 
819         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
820                 mutex_lock(&snd_card_mutex);
821                 if ((card = snd_cards[idx]) != NULL) {
822                         count++;
823                         snd_iprintf(buffer, "%s\n", card->longname);
824                 }
825                 mutex_unlock(&snd_card_mutex);
826         }
827         if (!count) {
828                 snd_iprintf(buffer, "--- no soundcards ---\n");
829         }
830 }
831 
832 #endif
833 
834 #ifdef MODULE
835 static void snd_card_module_info_read(struct snd_info_entry *entry,
836                                       struct snd_info_buffer *buffer)
837 {
838         int idx;
839         struct snd_card *card;
840 
841         for (idx = 0; idx < SNDRV_CARDS; idx++) {
842                 mutex_lock(&snd_card_mutex);
843                 if ((card = snd_cards[idx]) != NULL)
844                         snd_iprintf(buffer, "%2i %s\n",
845                                     idx, card->module->name);
846                 mutex_unlock(&snd_card_mutex);
847         }
848 }
849 #endif
850 
851 int __init snd_card_info_init(void)
852 {
853         struct snd_info_entry *entry;
854 
855         entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
856         if (! entry)
857                 return -ENOMEM;
858         entry->c.text.read = snd_card_info_read;
859         if (snd_info_register(entry) < 0)
860                 return -ENOMEM; /* freed in error path */
861 
862 #ifdef MODULE
863         entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
864         if (!entry)
865                 return -ENOMEM;
866         entry->c.text.read = snd_card_module_info_read;
867         if (snd_info_register(entry) < 0)
868                 return -ENOMEM; /* freed in error path */
869 #endif
870 
871         return 0;
872 }
873 #endif /* CONFIG_SND_PROC_FS */
874 
875 /**
876  *  snd_component_add - add a component string
877  *  @card: soundcard structure
878  *  @component: the component id string
879  *
880  *  This function adds the component id string to the supported list.
881  *  The component can be referred from the alsa-lib.
882  *
883  *  Return: Zero otherwise a negative error code.
884  */
885   
886 int snd_component_add(struct snd_card *card, const char *component)
887 {
888         char *ptr;
889         int len = strlen(component);
890 
891         ptr = strstr(card->components, component);
892         if (ptr != NULL) {
893                 if (ptr[len] == '\0' || ptr[len] == ' ')        /* already there */
894                         return 1;
895         }
896         if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
897                 snd_BUG();
898                 return -ENOMEM;
899         }
900         if (card->components[0] != '\0')
901                 strcat(card->components, " ");
902         strcat(card->components, component);
903         return 0;
904 }
905 EXPORT_SYMBOL(snd_component_add);
906 
907 /**
908  *  snd_card_file_add - add the file to the file list of the card
909  *  @card: soundcard structure
910  *  @file: file pointer
911  *
912  *  This function adds the file to the file linked-list of the card.
913  *  This linked-list is used to keep tracking the connection state,
914  *  and to avoid the release of busy resources by hotplug.
915  *
916  *  Return: zero or a negative error code.
917  */
918 int snd_card_file_add(struct snd_card *card, struct file *file)
919 {
920         struct snd_monitor_file *mfile;
921 
922         mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
923         if (mfile == NULL)
924                 return -ENOMEM;
925         mfile->file = file;
926         mfile->disconnected_f_op = NULL;
927         INIT_LIST_HEAD(&mfile->shutdown_list);
928         spin_lock(&card->files_lock);
929         if (card->shutdown) {
930                 spin_unlock(&card->files_lock);
931                 kfree(mfile);
932                 return -ENODEV;
933         }
934         list_add(&mfile->list, &card->files_list);
935         get_device(&card->card_dev);
936         spin_unlock(&card->files_lock);
937         return 0;
938 }
939 EXPORT_SYMBOL(snd_card_file_add);
940 
941 /**
942  *  snd_card_file_remove - remove the file from the file list
943  *  @card: soundcard structure
944  *  @file: file pointer
945  *
946  *  This function removes the file formerly added to the card via
947  *  snd_card_file_add() function.
948  *  If all files are removed and snd_card_free_when_closed() was
949  *  called beforehand, it processes the pending release of
950  *  resources.
951  *
952  *  Return: Zero or a negative error code.
953  */
954 int snd_card_file_remove(struct snd_card *card, struct file *file)
955 {
956         struct snd_monitor_file *mfile, *found = NULL;
957 
958         spin_lock(&card->files_lock);
959         list_for_each_entry(mfile, &card->files_list, list) {
960                 if (mfile->file == file) {
961                         list_del(&mfile->list);
962                         spin_lock(&shutdown_lock);
963                         list_del(&mfile->shutdown_list);
964                         spin_unlock(&shutdown_lock);
965                         if (mfile->disconnected_f_op)
966                                 fops_put(mfile->disconnected_f_op);
967                         found = mfile;
968                         break;
969                 }
970         }
971         if (list_empty(&card->files_list))
972                 wake_up_all(&card->remove_sleep);
973         spin_unlock(&card->files_lock);
974         if (!found) {
975                 dev_err(card->dev, "card file remove problem (%p)\n", file);
976                 return -ENOENT;
977         }
978         kfree(found);
979         put_device(&card->card_dev);
980         return 0;
981 }
982 EXPORT_SYMBOL(snd_card_file_remove);
983 
984 #ifdef CONFIG_PM
985 /**
986  *  snd_power_wait - wait until the power-state is changed.
987  *  @card: soundcard structure
988  *  @power_state: expected power state
989  *
990  *  Waits until the power-state is changed.
991  *
992  *  Return: Zero if successful, or a negative error code.
993  */
994 int snd_power_wait(struct snd_card *card, unsigned int power_state)
995 {
996         wait_queue_entry_t wait;
997         int result = 0;
998 
999         /* fastpath */
1000         if (snd_power_get_state(card) == power_state)
1001                 return 0;
1002         init_waitqueue_entry(&wait, current);
1003         add_wait_queue(&card->power_sleep, &wait);
1004         while (1) {
1005                 if (card->shutdown) {
1006                         result = -ENODEV;
1007                         break;
1008                 }
1009                 if (snd_power_get_state(card) == power_state)
1010                         break;
1011                 set_current_state(TASK_UNINTERRUPTIBLE);
1012                 schedule_timeout(30 * HZ);
1013         }
1014         remove_wait_queue(&card->power_sleep, &wait);
1015         return result;
1016 }
1017 EXPORT_SYMBOL(snd_power_wait);
1018 #endif /* CONFIG_PM */
1019 

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