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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/debugfs.h>
 17 #include <linux/completion.h>
 18 #include <linux/interrupt.h>
 19 
 20 #include <sound/core.h>
 21 #include <sound/control.h>
 22 #include <sound/info.h>
 23 
 24 /* monitor files for graceful shutdown (hotplug) */
 25 struct snd_monitor_file {
 26         struct file *file;
 27         const struct file_operations *disconnected_f_op;
 28         struct list_head shutdown_list; /* still need to shutdown */
 29         struct list_head list;  /* link of monitor files */
 30 };
 31 
 32 static DEFINE_SPINLOCK(shutdown_lock);
 33 static LIST_HEAD(shutdown_files);
 34 
 35 static const struct file_operations snd_shutdown_f_ops;
 36 
 37 /* locked for registering/using */
 38 static DECLARE_BITMAP(snd_cards_lock, SNDRV_CARDS);
 39 static struct snd_card *snd_cards[SNDRV_CARDS];
 40 
 41 static DEFINE_MUTEX(snd_card_mutex);
 42 
 43 static char *slots[SNDRV_CARDS];
 44 module_param_array(slots, charp, NULL, 0444);
 45 MODULE_PARM_DESC(slots, "Module names assigned to the slots.");
 46 
 47 /* return non-zero if the given index is reserved for the given
 48  * module via slots option
 49  */
 50 static int module_slot_match(struct module *module, int idx)
 51 {
 52         int match = 1;
 53 #ifdef MODULE
 54         const char *s1, *s2;
 55 
 56         if (!module || !*module->name || !slots[idx])
 57                 return 0;
 58 
 59         s1 = module->name;
 60         s2 = slots[idx];
 61         if (*s2 == '!') {
 62                 match = 0; /* negative match */
 63                 s2++;
 64         }
 65         /* compare module name strings
 66          * hyphens are handled as equivalent with underscore
 67          */
 68         for (;;) {
 69                 char c1 = *s1++;
 70                 char c2 = *s2++;
 71                 if (c1 == '-')
 72                         c1 = '_';
 73                 if (c2 == '-')
 74                         c2 = '_';
 75                 if (c1 != c2)
 76                         return !match;
 77                 if (!c1)
 78                         break;
 79         }
 80 #endif /* MODULE */
 81         return match;
 82 }
 83 
 84 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 85 int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
 86 EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
 87 #endif
 88 
 89 static int check_empty_slot(struct module *module, int slot)
 90 {
 91         return !slots[slot] || !*slots[slot];
 92 }
 93 
 94 /* return an empty slot number (>= 0) found in the given bitmask @mask.
 95  * @mask == -1 == 0xffffffff means: take any free slot up to 32
 96  * when no slot is available, return the original @mask as is.
 97  */
 98 static int get_slot_from_bitmask(int mask, int (*check)(struct module *, int),
 99                                  struct module *module)
100 {
101         int slot;
102 
103         for (slot = 0; slot < SNDRV_CARDS; slot++) {
104                 if (slot < 32 && !(mask & (1U << slot)))
105                         continue;
106                 if (!test_bit(slot, snd_cards_lock)) {
107                         if (check(module, slot))
108                                 return slot; /* found */
109                 }
110         }
111         return mask; /* unchanged */
112 }
113 
114 /* the default release callback set in snd_device_initialize() below;
115  * this is just NOP for now, as almost all jobs are already done in
116  * dev_free callback of snd_device chain instead.
117  */
118 static void default_release(struct device *dev)
119 {
120 }
121 
122 /**
123  * snd_device_initialize - Initialize struct device for sound devices
124  * @dev: device to initialize
125  * @card: card to assign, optional
126  */
127 void snd_device_initialize(struct device *dev, struct snd_card *card)
128 {
129         device_initialize(dev);
130         if (card)
131                 dev->parent = &card->card_dev;
132         dev->class = sound_class;
133         dev->release = default_release;
134 }
135 EXPORT_SYMBOL_GPL(snd_device_initialize);
136 
137 static int snd_card_init(struct snd_card *card, struct device *parent,
138                          int idx, const char *xid, struct module *module,
139                          size_t extra_size);
140 static int snd_card_do_free(struct snd_card *card);
141 static const struct attribute_group card_dev_attr_group;
142 
143 static void release_card_device(struct device *dev)
144 {
145         snd_card_do_free(dev_to_snd_card(dev));
146 }
147 
148 /**
149  *  snd_card_new - create and initialize a soundcard structure
150  *  @parent: the parent device object
151  *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
152  *  @xid: card identification (ASCII string)
153  *  @module: top level module for locking
154  *  @extra_size: allocate this extra size after the main soundcard structure
155  *  @card_ret: the pointer to store the created card instance
156  *
157  *  The function allocates snd_card instance via kzalloc with the given
158  *  space for the driver to use freely.  The allocated struct is stored
159  *  in the given card_ret pointer.
160  *
161  *  Return: Zero if successful or a negative error code.
162  */
163 int snd_card_new(struct device *parent, int idx, const char *xid,
164                     struct module *module, int extra_size,
165                     struct snd_card **card_ret)
166 {
167         struct snd_card *card;
168         int err;
169 
170         if (snd_BUG_ON(!card_ret))
171                 return -EINVAL;
172         *card_ret = NULL;
173 
174         if (extra_size < 0)
175                 extra_size = 0;
176         card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
177         if (!card)
178                 return -ENOMEM;
179 
180         err = snd_card_init(card, parent, idx, xid, module, extra_size);
181         if (err < 0) {
182                 kfree(card);
183                 return err;
184         }
185 
186         *card_ret = card;
187         return 0;
188 }
189 EXPORT_SYMBOL(snd_card_new);
190 
191 static void __snd_card_release(struct device *dev, void *data)
192 {
193         snd_card_free(data);
194 }
195 
196 /**
197  * snd_devm_card_new - managed snd_card object creation
198  * @parent: the parent device object
199  * @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
200  * @xid: card identification (ASCII string)
201  * @module: top level module for locking
202  * @extra_size: allocate this extra size after the main soundcard structure
203  * @card_ret: the pointer to store the created card instance
204  *
205  * This function works like snd_card_new() but manages the allocated resource
206  * via devres, i.e. you don't need to free explicitly.
207  *
208  * When a snd_card object is created with this function and registered via
209  * snd_card_register(), the very first devres action to call snd_card_free()
210  * is added automatically.  In that way, the resource disconnection is assured
211  * at first, then released in the expected order.
212  */
213 int snd_devm_card_new(struct device *parent, int idx, const char *xid,
214                       struct module *module, size_t extra_size,
215                       struct snd_card **card_ret)
216 {
217         struct snd_card *card;
218         int err;
219 
220         *card_ret = NULL;
221         card = devres_alloc(__snd_card_release, sizeof(*card) + extra_size,
222                             GFP_KERNEL);
223         if (!card)
224                 return -ENOMEM;
225         card->managed = true;
226         err = snd_card_init(card, parent, idx, xid, module, extra_size);
227         if (err < 0) {
228                 devres_free(card);
229                 return err;
230         }
231 
232         devres_add(parent, card);
233         *card_ret = card;
234         return 0;
235 }
236 EXPORT_SYMBOL_GPL(snd_devm_card_new);
237 
238 static int snd_card_init(struct snd_card *card, struct device *parent,
239                          int idx, const char *xid, struct module *module,
240                          size_t extra_size)
241 {
242         int err;
243 #ifdef CONFIG_SND_DEBUG
244         char name[8];
245 #endif
246 
247         if (extra_size > 0)
248                 card->private_data = (char *)card + sizeof(struct snd_card);
249         if (xid)
250                 strscpy(card->id, xid, sizeof(card->id));
251         err = 0;
252         mutex_lock(&snd_card_mutex);
253         if (idx < 0) /* first check the matching module-name slot */
254                 idx = get_slot_from_bitmask(idx, module_slot_match, module);
255         if (idx < 0) /* if not matched, assign an empty slot */
256                 idx = get_slot_from_bitmask(idx, check_empty_slot, module);
257         if (idx < 0)
258                 err = -ENODEV;
259         else if (idx < snd_ecards_limit) {
260                 if (test_bit(idx, snd_cards_lock))
261                         err = -EBUSY;   /* invalid */
262         } else if (idx >= SNDRV_CARDS)
263                 err = -ENODEV;
264         if (err < 0) {
265                 mutex_unlock(&snd_card_mutex);
266                 dev_err(parent, "cannot find the slot for index %d (range 0-%i), error: %d\n",
267                          idx, snd_ecards_limit - 1, err);
268                 return err;
269         }
270         set_bit(idx, snd_cards_lock);           /* lock it */
271         if (idx >= snd_ecards_limit)
272                 snd_ecards_limit = idx + 1; /* increase the limit */
273         mutex_unlock(&snd_card_mutex);
274         card->dev = parent;
275         card->number = idx;
276 #ifdef MODULE
277         WARN_ON(!module);
278         card->module = module;
279 #endif
280         INIT_LIST_HEAD(&card->devices);
281         init_rwsem(&card->controls_rwsem);
282         rwlock_init(&card->ctl_files_rwlock);
283         INIT_LIST_HEAD(&card->controls);
284         INIT_LIST_HEAD(&card->ctl_files);
285         spin_lock_init(&card->files_lock);
286         INIT_LIST_HEAD(&card->files_list);
287         mutex_init(&card->memory_mutex);
288 #ifdef CONFIG_PM
289         init_waitqueue_head(&card->power_sleep);
290         init_waitqueue_head(&card->power_ref_sleep);
291         atomic_set(&card->power_ref, 0);
292 #endif
293         init_waitqueue_head(&card->remove_sleep);
294         card->sync_irq = -1;
295 
296         device_initialize(&card->card_dev);
297         card->card_dev.parent = parent;
298         card->card_dev.class = sound_class;
299         card->card_dev.release = release_card_device;
300         card->card_dev.groups = card->dev_groups;
301         card->dev_groups[0] = &card_dev_attr_group;
302         err = kobject_set_name(&card->card_dev.kobj, "card%d", idx);
303         if (err < 0)
304                 goto __error;
305 
306         snprintf(card->irq_descr, sizeof(card->irq_descr), "%s:%s",
307                  dev_driver_string(card->dev), dev_name(&card->card_dev));
308 
309         /* the control interface cannot be accessed from the user space until */
310         /* snd_cards_bitmask and snd_cards are set with snd_card_register */
311         err = snd_ctl_create(card);
312         if (err < 0) {
313                 dev_err(parent, "unable to register control minors\n");
314                 goto __error;
315         }
316         err = snd_info_card_create(card);
317         if (err < 0) {
318                 dev_err(parent, "unable to create card info\n");
319                 goto __error_ctl;
320         }
321 
322 #ifdef CONFIG_SND_DEBUG
323         sprintf(name, "card%d", idx);
324         card->debugfs_root = debugfs_create_dir(name, sound_debugfs_root);
325 #endif
326         return 0;
327 
328       __error_ctl:
329         snd_device_free_all(card);
330       __error:
331         put_device(&card->card_dev);
332         return err;
333 }
334 
335 /**
336  * snd_card_ref - Get the card object from the index
337  * @idx: the card index
338  *
339  * Returns a card object corresponding to the given index or NULL if not found.
340  * Release the object via snd_card_unref().
341  */
342 struct snd_card *snd_card_ref(int idx)
343 {
344         struct snd_card *card;
345 
346         mutex_lock(&snd_card_mutex);
347         card = snd_cards[idx];
348         if (card)
349                 get_device(&card->card_dev);
350         mutex_unlock(&snd_card_mutex);
351         return card;
352 }
353 EXPORT_SYMBOL_GPL(snd_card_ref);
354 
355 /* return non-zero if a card is already locked */
356 int snd_card_locked(int card)
357 {
358         int locked;
359 
360         mutex_lock(&snd_card_mutex);
361         locked = test_bit(card, snd_cards_lock);
362         mutex_unlock(&snd_card_mutex);
363         return locked;
364 }
365 
366 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
367 {
368         return -ENODEV;
369 }
370 
371 static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
372                                    size_t count, loff_t *offset)
373 {
374         return -ENODEV;
375 }
376 
377 static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
378                                     size_t count, loff_t *offset)
379 {
380         return -ENODEV;
381 }
382 
383 static int snd_disconnect_release(struct inode *inode, struct file *file)
384 {
385         struct snd_monitor_file *df = NULL, *_df;
386 
387         spin_lock(&shutdown_lock);
388         list_for_each_entry(_df, &shutdown_files, shutdown_list) {
389                 if (_df->file == file) {
390                         df = _df;
391                         list_del_init(&df->shutdown_list);
392                         break;
393                 }
394         }
395         spin_unlock(&shutdown_lock);
396 
397         if (likely(df)) {
398                 if ((file->f_flags & FASYNC) && df->disconnected_f_op->fasync)
399                         df->disconnected_f_op->fasync(-1, file, 0);
400                 return df->disconnected_f_op->release(inode, file);
401         }
402 
403         panic("%s(%p, %p) failed!", __func__, inode, file);
404 }
405 
406 static __poll_t snd_disconnect_poll(struct file * file, poll_table * wait)
407 {
408         return EPOLLERR | EPOLLNVAL;
409 }
410 
411 static long snd_disconnect_ioctl(struct file *file,
412                                  unsigned int cmd, unsigned long arg)
413 {
414         return -ENODEV;
415 }
416 
417 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
418 {
419         return -ENODEV;
420 }
421 
422 static int snd_disconnect_fasync(int fd, struct file *file, int on)
423 {
424         return -ENODEV;
425 }
426 
427 static const struct file_operations snd_shutdown_f_ops =
428 {
429         .owner =        THIS_MODULE,
430         .llseek =       snd_disconnect_llseek,
431         .read =         snd_disconnect_read,
432         .write =        snd_disconnect_write,
433         .release =      snd_disconnect_release,
434         .poll =         snd_disconnect_poll,
435         .unlocked_ioctl = snd_disconnect_ioctl,
436 #ifdef CONFIG_COMPAT
437         .compat_ioctl = snd_disconnect_ioctl,
438 #endif
439         .mmap =         snd_disconnect_mmap,
440         .fasync =       snd_disconnect_fasync
441 };
442 
443 /**
444  *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
445  *  @card: soundcard structure
446  *
447  *  Disconnects all APIs from the file-operations (user space).
448  *
449  *  Return: Zero, otherwise a negative error code.
450  *
451  *  Note: The current implementation replaces all active file->f_op with special
452  *        dummy file operations (they do nothing except release).
453  */
454 int snd_card_disconnect(struct snd_card *card)
455 {
456         struct snd_monitor_file *mfile;
457 
458         if (!card)
459                 return -EINVAL;
460 
461         spin_lock(&card->files_lock);
462         if (card->shutdown) {
463                 spin_unlock(&card->files_lock);
464                 return 0;
465         }
466         card->shutdown = 1;
467 
468         /* replace file->f_op with special dummy operations */
469         list_for_each_entry(mfile, &card->files_list, list) {
470                 /* it's critical part, use endless loop */
471                 /* we have no room to fail */
472                 mfile->disconnected_f_op = mfile->file->f_op;
473 
474                 spin_lock(&shutdown_lock);
475                 list_add(&mfile->shutdown_list, &shutdown_files);
476                 spin_unlock(&shutdown_lock);
477 
478                 mfile->file->f_op = &snd_shutdown_f_ops;
479                 fops_get(mfile->file->f_op);
480         }
481         spin_unlock(&card->files_lock); 
482 
483         /* notify all connected devices about disconnection */
484         /* at this point, they cannot respond to any calls except release() */
485 
486 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
487         if (snd_mixer_oss_notify_callback)
488                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
489 #endif
490 
491         /* notify all devices that we are disconnected */
492         snd_device_disconnect_all(card);
493 
494         if (card->sync_irq > 0)
495                 synchronize_irq(card->sync_irq);
496 
497         snd_info_card_disconnect(card);
498         if (card->registered) {
499                 device_del(&card->card_dev);
500                 card->registered = false;
501         }
502 
503         /* disable fops (user space) operations for ALSA API */
504         mutex_lock(&snd_card_mutex);
505         snd_cards[card->number] = NULL;
506         clear_bit(card->number, snd_cards_lock);
507         mutex_unlock(&snd_card_mutex);
508 
509 #ifdef CONFIG_PM
510         wake_up(&card->power_sleep);
511         snd_power_sync_ref(card);
512 #endif
513         return 0;       
514 }
515 EXPORT_SYMBOL(snd_card_disconnect);
516 
517 /**
518  * snd_card_disconnect_sync - disconnect card and wait until files get closed
519  * @card: card object to disconnect
520  *
521  * This calls snd_card_disconnect() for disconnecting all belonging components
522  * and waits until all pending files get closed.
523  * It assures that all accesses from user-space finished so that the driver
524  * can release its resources gracefully.
525  */
526 void snd_card_disconnect_sync(struct snd_card *card)
527 {
528         int err;
529 
530         err = snd_card_disconnect(card);
531         if (err < 0) {
532                 dev_err(card->dev,
533                         "snd_card_disconnect error (%d), skipping sync\n",
534                         err);
535                 return;
536         }
537 
538         spin_lock_irq(&card->files_lock);
539         wait_event_lock_irq(card->remove_sleep,
540                             list_empty(&card->files_list),
541                             card->files_lock);
542         spin_unlock_irq(&card->files_lock);
543 }
544 EXPORT_SYMBOL_GPL(snd_card_disconnect_sync);
545 
546 static int snd_card_do_free(struct snd_card *card)
547 {
548         card->releasing = true;
549 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
550         if (snd_mixer_oss_notify_callback)
551                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
552 #endif
553         snd_device_free_all(card);
554         if (card->private_free)
555                 card->private_free(card);
556         if (snd_info_card_free(card) < 0) {
557                 dev_warn(card->dev, "unable to free card info\n");
558                 /* Not fatal error */
559         }
560 #ifdef CONFIG_SND_DEBUG
561         debugfs_remove(card->debugfs_root);
562         card->debugfs_root = NULL;
563 #endif
564         if (card->release_completion)
565                 complete(card->release_completion);
566         if (!card->managed)
567                 kfree(card);
568         return 0;
569 }
570 
571 /**
572  * snd_card_free_when_closed - Disconnect the card, free it later eventually
573  * @card: soundcard structure
574  *
575  * Unlike snd_card_free(), this function doesn't try to release the card
576  * resource immediately, but tries to disconnect at first.  When the card
577  * is still in use, the function returns before freeing the resources.
578  * The card resources will be freed when the refcount gets to zero.
579  */
580 int snd_card_free_when_closed(struct snd_card *card)
581 {
582         int ret = snd_card_disconnect(card);
583         if (ret)
584                 return ret;
585         put_device(&card->card_dev);
586         return 0;
587 }
588 EXPORT_SYMBOL(snd_card_free_when_closed);
589 
590 /**
591  * snd_card_free - frees given soundcard structure
592  * @card: soundcard structure
593  *
594  * This function releases the soundcard structure and the all assigned
595  * devices automatically.  That is, you don't have to release the devices
596  * by yourself.
597  *
598  * This function waits until the all resources are properly released.
599  *
600  * Return: Zero. Frees all associated devices and frees the control
601  * interface associated to given soundcard.
602  */
603 int snd_card_free(struct snd_card *card)
604 {
605         DECLARE_COMPLETION_ONSTACK(released);
606         int ret;
607 
608         /* The call of snd_card_free() is allowed from various code paths;
609          * a manual call from the driver and the call via devres_free, and
610          * we need to avoid double-free. Moreover, the release via devres
611          * may call snd_card_free() twice due to its nature, we need to have
612          * the check here at the beginning.
613          */
614         if (card->releasing)
615                 return 0;
616 
617         card->release_completion = &released;
618         ret = snd_card_free_when_closed(card);
619         if (ret)
620                 return ret;
621         /* wait, until all devices are ready for the free operation */
622         wait_for_completion(&released);
623 
624         return 0;
625 }
626 EXPORT_SYMBOL(snd_card_free);
627 
628 /* retrieve the last word of shortname or longname */
629 static const char *retrieve_id_from_card_name(const char *name)
630 {
631         const char *spos = name;
632 
633         while (*name) {
634                 if (isspace(*name) && isalnum(name[1]))
635                         spos = name + 1;
636                 name++;
637         }
638         return spos;
639 }
640 
641 /* return true if the given id string doesn't conflict any other card ids */
642 static bool card_id_ok(struct snd_card *card, const char *id)
643 {
644         int i;
645         if (!snd_info_check_reserved_words(id))
646                 return false;
647         for (i = 0; i < snd_ecards_limit; i++) {
648                 if (snd_cards[i] && snd_cards[i] != card &&
649                     !strcmp(snd_cards[i]->id, id))
650                         return false;
651         }
652         return true;
653 }
654 
655 /* copy to card->id only with valid letters from nid */
656 static void copy_valid_id_string(struct snd_card *card, const char *src,
657                                  const char *nid)
658 {
659         char *id = card->id;
660 
661         while (*nid && !isalnum(*nid))
662                 nid++;
663         if (isdigit(*nid))
664                 *id++ = isalpha(*src) ? *src : 'D';
665         while (*nid && (size_t)(id - card->id) < sizeof(card->id) - 1) {
666                 if (isalnum(*nid))
667                         *id++ = *nid;
668                 nid++;
669         }
670         *id = 0;
671 }
672 
673 /* Set card->id from the given string
674  * If the string conflicts with other ids, add a suffix to make it unique.
675  */
676 static void snd_card_set_id_no_lock(struct snd_card *card, const char *src,
677                                     const char *nid)
678 {
679         int len, loops;
680         bool is_default = false;
681         char *id;
682         
683         copy_valid_id_string(card, src, nid);
684         id = card->id;
685 
686  again:
687         /* use "Default" for obviously invalid strings
688          * ("card" conflicts with proc directories)
689          */
690         if (!*id || !strncmp(id, "card", 4)) {
691                 strcpy(id, "Default");
692                 is_default = true;
693         }
694 
695         len = strlen(id);
696         for (loops = 0; loops < SNDRV_CARDS; loops++) {
697                 char *spos;
698                 char sfxstr[5]; /* "_012" */
699                 int sfxlen;
700 
701                 if (card_id_ok(card, id))
702                         return; /* OK */
703 
704                 /* Add _XYZ suffix */
705                 sprintf(sfxstr, "_%X", loops + 1);
706                 sfxlen = strlen(sfxstr);
707                 if (len + sfxlen >= sizeof(card->id))
708                         spos = id + sizeof(card->id) - sfxlen - 1;
709                 else
710                         spos = id + len;
711                 strcpy(spos, sfxstr);
712         }
713         /* fallback to the default id */
714         if (!is_default) {
715                 *id = 0;
716                 goto again;
717         }
718         /* last resort... */
719         dev_err(card->dev, "unable to set card id (%s)\n", id);
720         if (card->proc_root->name)
721                 strscpy(card->id, card->proc_root->name, sizeof(card->id));
722 }
723 
724 /**
725  *  snd_card_set_id - set card identification name
726  *  @card: soundcard structure
727  *  @nid: new identification string
728  *
729  *  This function sets the card identification and checks for name
730  *  collisions.
731  */
732 void snd_card_set_id(struct snd_card *card, const char *nid)
733 {
734         /* check if user specified own card->id */
735         if (card->id[0] != '\0')
736                 return;
737         mutex_lock(&snd_card_mutex);
738         snd_card_set_id_no_lock(card, nid, nid);
739         mutex_unlock(&snd_card_mutex);
740 }
741 EXPORT_SYMBOL(snd_card_set_id);
742 
743 static ssize_t id_show(struct device *dev,
744                        struct device_attribute *attr, char *buf)
745 {
746         struct snd_card *card = container_of(dev, struct snd_card, card_dev);
747         return scnprintf(buf, PAGE_SIZE, "%s\n", card->id);
748 }
749 
750 static ssize_t id_store(struct device *dev, struct device_attribute *attr,
751                         const char *buf, size_t count)
752 {
753         struct snd_card *card = container_of(dev, struct snd_card, card_dev);
754         char buf1[sizeof(card->id)];
755         size_t copy = count > sizeof(card->id) - 1 ?
756                                         sizeof(card->id) - 1 : count;
757         size_t idx;
758         int c;
759 
760         for (idx = 0; idx < copy; idx++) {
761                 c = buf[idx];
762                 if (!isalnum(c) && c != '_' && c != '-')
763                         return -EINVAL;
764         }
765         memcpy(buf1, buf, copy);
766         buf1[copy] = '\0';
767         mutex_lock(&snd_card_mutex);
768         if (!card_id_ok(NULL, buf1)) {
769                 mutex_unlock(&snd_card_mutex);
770                 return -EEXIST;
771         }
772         strcpy(card->id, buf1);
773         snd_info_card_id_change(card);
774         mutex_unlock(&snd_card_mutex);
775 
776         return count;
777 }
778 
779 static DEVICE_ATTR_RW(id);
780 
781 static ssize_t number_show(struct device *dev,
782                            struct device_attribute *attr, char *buf)
783 {
784         struct snd_card *card = container_of(dev, struct snd_card, card_dev);
785         return scnprintf(buf, PAGE_SIZE, "%i\n", card->number);
786 }
787 
788 static DEVICE_ATTR_RO(number);
789 
790 static struct attribute *card_dev_attrs[] = {
791         &dev_attr_id.attr,
792         &dev_attr_number.attr,
793         NULL
794 };
795 
796 static const struct attribute_group card_dev_attr_group = {
797         .attrs  = card_dev_attrs,
798 };
799 
800 /**
801  * snd_card_add_dev_attr - Append a new sysfs attribute group to card
802  * @card: card instance
803  * @group: attribute group to append
804  */
805 int snd_card_add_dev_attr(struct snd_card *card,
806                           const struct attribute_group *group)
807 {
808         int i;
809 
810         /* loop for (arraysize-1) here to keep NULL at the last entry */
811         for (i = 0; i < ARRAY_SIZE(card->dev_groups) - 1; i++) {
812                 if (!card->dev_groups[i]) {
813                         card->dev_groups[i] = group;
814                         return 0;
815                 }
816         }
817 
818         dev_err(card->dev, "Too many groups assigned\n");
819         return -ENOSPC;
820 }
821 EXPORT_SYMBOL_GPL(snd_card_add_dev_attr);
822 
823 static void trigger_card_free(void *data)
824 {
825         snd_card_free(data);
826 }
827 
828 /**
829  *  snd_card_register - register the soundcard
830  *  @card: soundcard structure
831  *
832  *  This function registers all the devices assigned to the soundcard.
833  *  Until calling this, the ALSA control interface is blocked from the
834  *  external accesses.  Thus, you should call this function at the end
835  *  of the initialization of the card.
836  *
837  *  Return: Zero otherwise a negative error code if the registration failed.
838  */
839 int snd_card_register(struct snd_card *card)
840 {
841         int err;
842 
843         if (snd_BUG_ON(!card))
844                 return -EINVAL;
845 
846         if (!card->registered) {
847                 err = device_add(&card->card_dev);
848                 if (err < 0)
849                         return err;
850                 card->registered = true;
851         } else {
852                 if (card->managed)
853                         devm_remove_action(card->dev, trigger_card_free, card);
854         }
855 
856         if (card->managed) {
857                 err = devm_add_action(card->dev, trigger_card_free, card);
858                 if (err < 0)
859                         return err;
860         }
861 
862         err = snd_device_register_all(card);
863         if (err < 0)
864                 return err;
865         mutex_lock(&snd_card_mutex);
866         if (snd_cards[card->number]) {
867                 /* already registered */
868                 mutex_unlock(&snd_card_mutex);
869                 return snd_info_card_register(card); /* register pending info */
870         }
871         if (*card->id) {
872                 /* make a unique id name from the given string */
873                 char tmpid[sizeof(card->id)];
874                 memcpy(tmpid, card->id, sizeof(card->id));
875                 snd_card_set_id_no_lock(card, tmpid, tmpid);
876         } else {
877                 /* create an id from either shortname or longname */
878                 const char *src;
879                 src = *card->shortname ? card->shortname : card->longname;
880                 snd_card_set_id_no_lock(card, src,
881                                         retrieve_id_from_card_name(src));
882         }
883         snd_cards[card->number] = card;
884         mutex_unlock(&snd_card_mutex);
885         err = snd_info_card_register(card);
886         if (err < 0)
887                 return err;
888 
889 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
890         if (snd_mixer_oss_notify_callback)
891                 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
892 #endif
893         return 0;
894 }
895 EXPORT_SYMBOL(snd_card_register);
896 
897 #ifdef CONFIG_SND_PROC_FS
898 static void snd_card_info_read(struct snd_info_entry *entry,
899                                struct snd_info_buffer *buffer)
900 {
901         int idx, count;
902         struct snd_card *card;
903 
904         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
905                 mutex_lock(&snd_card_mutex);
906                 card = snd_cards[idx];
907                 if (card) {
908                         count++;
909                         snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
910                                         idx,
911                                         card->id,
912                                         card->driver,
913                                         card->shortname);
914                         snd_iprintf(buffer, "                      %s\n",
915                                         card->longname);
916                 }
917                 mutex_unlock(&snd_card_mutex);
918         }
919         if (!count)
920                 snd_iprintf(buffer, "--- no soundcards ---\n");
921 }
922 
923 #ifdef CONFIG_SND_OSSEMUL
924 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
925 {
926         int idx, count;
927         struct snd_card *card;
928 
929         for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
930                 mutex_lock(&snd_card_mutex);
931                 card = snd_cards[idx];
932                 if (card) {
933                         count++;
934                         snd_iprintf(buffer, "%s\n", card->longname);
935                 }
936                 mutex_unlock(&snd_card_mutex);
937         }
938         if (!count) {
939                 snd_iprintf(buffer, "--- no soundcards ---\n");
940         }
941 }
942 
943 #endif
944 
945 #ifdef MODULE
946 static void snd_card_module_info_read(struct snd_info_entry *entry,
947                                       struct snd_info_buffer *buffer)
948 {
949         int idx;
950         struct snd_card *card;
951 
952         for (idx = 0; idx < SNDRV_CARDS; idx++) {
953                 mutex_lock(&snd_card_mutex);
954                 card = snd_cards[idx];
955                 if (card)
956                         snd_iprintf(buffer, "%2i %s\n",
957                                     idx, card->module->name);
958                 mutex_unlock(&snd_card_mutex);
959         }
960 }
961 #endif
962 
963 int __init snd_card_info_init(void)
964 {
965         struct snd_info_entry *entry;
966 
967         entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
968         if (! entry)
969                 return -ENOMEM;
970         entry->c.text.read = snd_card_info_read;
971         if (snd_info_register(entry) < 0)
972                 return -ENOMEM; /* freed in error path */
973 
974 #ifdef MODULE
975         entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
976         if (!entry)
977                 return -ENOMEM;
978         entry->c.text.read = snd_card_module_info_read;
979         if (snd_info_register(entry) < 0)
980                 return -ENOMEM; /* freed in error path */
981 #endif
982 
983         return 0;
984 }
985 #endif /* CONFIG_SND_PROC_FS */
986 
987 /**
988  *  snd_component_add - add a component string
989  *  @card: soundcard structure
990  *  @component: the component id string
991  *
992  *  This function adds the component id string to the supported list.
993  *  The component can be referred from the alsa-lib.
994  *
995  *  Return: Zero otherwise a negative error code.
996  */
997   
998 int snd_component_add(struct snd_card *card, const char *component)
999 {
1000         char *ptr;
1001         int len = strlen(component);
1002 
1003         ptr = strstr(card->components, component);
1004         if (ptr != NULL) {
1005                 if (ptr[len] == '\0' || ptr[len] == ' ')        /* already there */
1006                         return 1;
1007         }
1008         if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
1009                 snd_BUG();
1010                 return -ENOMEM;
1011         }
1012         if (card->components[0] != '\0')
1013                 strcat(card->components, " ");
1014         strcat(card->components, component);
1015         return 0;
1016 }
1017 EXPORT_SYMBOL(snd_component_add);
1018 
1019 /**
1020  *  snd_card_file_add - add the file to the file list of the card
1021  *  @card: soundcard structure
1022  *  @file: file pointer
1023  *
1024  *  This function adds the file to the file linked-list of the card.
1025  *  This linked-list is used to keep tracking the connection state,
1026  *  and to avoid the release of busy resources by hotplug.
1027  *
1028  *  Return: zero or a negative error code.
1029  */
1030 int snd_card_file_add(struct snd_card *card, struct file *file)
1031 {
1032         struct snd_monitor_file *mfile;
1033 
1034         mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
1035         if (mfile == NULL)
1036                 return -ENOMEM;
1037         mfile->file = file;
1038         mfile->disconnected_f_op = NULL;
1039         INIT_LIST_HEAD(&mfile->shutdown_list);
1040         spin_lock(&card->files_lock);
1041         if (card->shutdown) {
1042                 spin_unlock(&card->files_lock);
1043                 kfree(mfile);
1044                 return -ENODEV;
1045         }
1046         list_add(&mfile->list, &card->files_list);
1047         get_device(&card->card_dev);
1048         spin_unlock(&card->files_lock);
1049         return 0;
1050 }
1051 EXPORT_SYMBOL(snd_card_file_add);
1052 
1053 /**
1054  *  snd_card_file_remove - remove the file from the file list
1055  *  @card: soundcard structure
1056  *  @file: file pointer
1057  *
1058  *  This function removes the file formerly added to the card via
1059  *  snd_card_file_add() function.
1060  *  If all files are removed and snd_card_free_when_closed() was
1061  *  called beforehand, it processes the pending release of
1062  *  resources.
1063  *
1064  *  Return: Zero or a negative error code.
1065  */
1066 int snd_card_file_remove(struct snd_card *card, struct file *file)
1067 {
1068         struct snd_monitor_file *mfile, *found = NULL;
1069 
1070         spin_lock(&card->files_lock);
1071         list_for_each_entry(mfile, &card->files_list, list) {
1072                 if (mfile->file == file) {
1073                         list_del(&mfile->list);
1074                         spin_lock(&shutdown_lock);
1075                         list_del(&mfile->shutdown_list);
1076                         spin_unlock(&shutdown_lock);
1077                         if (mfile->disconnected_f_op)
1078                                 fops_put(mfile->disconnected_f_op);
1079                         found = mfile;
1080                         break;
1081                 }
1082         }
1083         if (list_empty(&card->files_list))
1084                 wake_up_all(&card->remove_sleep);
1085         spin_unlock(&card->files_lock);
1086         if (!found) {
1087                 dev_err(card->dev, "card file remove problem (%p)\n", file);
1088                 return -ENOENT;
1089         }
1090         kfree(found);
1091         put_device(&card->card_dev);
1092         return 0;
1093 }
1094 EXPORT_SYMBOL(snd_card_file_remove);
1095 
1096 #ifdef CONFIG_PM
1097 /**
1098  * snd_power_ref_and_wait - wait until the card gets powered up
1099  * @card: soundcard structure
1100  *
1101  * Take the power_ref reference count of the given card, and
1102  * wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
1103  * The refcount is down again while sleeping until power-up, hence this
1104  * function can be used for syncing the floating control ops accesses,
1105  * typically around calling control ops.
1106  *
1107  * The caller needs to pull down the refcount via snd_power_unref() later
1108  * no matter whether the error is returned from this function or not.
1109  *
1110  * Return: Zero if successful, or a negative error code.
1111  */
1112 int snd_power_ref_and_wait(struct snd_card *card)
1113 {
1114         wait_queue_entry_t wait;
1115         int result = 0;
1116 
1117         snd_power_ref(card);
1118         /* fastpath */
1119         if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
1120                 return 0;
1121         init_waitqueue_entry(&wait, current);
1122         add_wait_queue(&card->power_sleep, &wait);
1123         while (1) {
1124                 if (card->shutdown) {
1125                         result = -ENODEV;
1126                         break;
1127                 }
1128                 if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
1129                         break;
1130                 snd_power_unref(card);
1131                 set_current_state(TASK_UNINTERRUPTIBLE);
1132                 schedule_timeout(30 * HZ);
1133                 snd_power_ref(card);
1134         }
1135         remove_wait_queue(&card->power_sleep, &wait);
1136         return result;
1137 }
1138 EXPORT_SYMBOL_GPL(snd_power_ref_and_wait);
1139 
1140 /**
1141  * snd_power_wait - wait until the card gets powered up (old form)
1142  * @card: soundcard structure
1143  *
1144  * Wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
1145  *
1146  * Return: Zero if successful, or a negative error code.
1147  */
1148 int snd_power_wait(struct snd_card *card)
1149 {
1150         int ret;
1151 
1152         ret = snd_power_ref_and_wait(card);
1153         snd_power_unref(card);
1154         return ret;
1155 }
1156 EXPORT_SYMBOL(snd_power_wait);
1157 #endif /* CONFIG_PM */
1158 

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