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 CONFIG_MODULES
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 /* CONFIG_MODULES */
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_alloc() */
115 static void default_release_alloc(struct device *dev)
116 {
117 kfree(dev);
118 }
119
120 /**
121 * snd_device_alloc - Allocate and initialize struct device for sound devices
122 * @dev_p: pointer to store the allocated device
123 * @card: card to assign, optional
124 *
125 * For releasing the allocated device, call put_device().
126 */
127 int snd_device_alloc(struct device **dev_p, struct snd_card *card)
128 {
129 struct device *dev;
130
131 *dev_p = NULL;
132 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
133 if (!dev)
134 return -ENOMEM;
135 device_initialize(dev);
136 if (card)
137 dev->parent = &card->card_dev;
138 dev->class = &sound_class;
139 dev->release = default_release_alloc;
140 *dev_p = dev;
141 return 0;
142 }
143 EXPORT_SYMBOL_GPL(snd_device_alloc);
144
145 static int snd_card_init(struct snd_card *card, struct device *parent,
146 int idx, const char *xid, struct module *module,
147 size_t extra_size);
148 static int snd_card_do_free(struct snd_card *card);
149 static const struct attribute_group card_dev_attr_group;
150
151 static void release_card_device(struct device *dev)
152 {
153 snd_card_do_free(dev_to_snd_card(dev));
154 }
155
156 /**
157 * snd_card_new - create and initialize a soundcard structure
158 * @parent: the parent device object
159 * @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
160 * @xid: card identification (ASCII string)
161 * @module: top level module for locking
162 * @extra_size: allocate this extra size after the main soundcard structure
163 * @card_ret: the pointer to store the created card instance
164 *
165 * The function allocates snd_card instance via kzalloc with the given
166 * space for the driver to use freely. The allocated struct is stored
167 * in the given card_ret pointer.
168 *
169 * Return: Zero if successful or a negative error code.
170 */
171 int snd_card_new(struct device *parent, int idx, const char *xid,
172 struct module *module, int extra_size,
173 struct snd_card **card_ret)
174 {
175 struct snd_card *card;
176 int err;
177
178 if (snd_BUG_ON(!card_ret))
179 return -EINVAL;
180 *card_ret = NULL;
181
182 if (extra_size < 0)
183 extra_size = 0;
184 card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
185 if (!card)
186 return -ENOMEM;
187
188 err = snd_card_init(card, parent, idx, xid, module, extra_size);
189 if (err < 0)
190 return err; /* card is freed by error handler */
191
192 *card_ret = card;
193 return 0;
194 }
195 EXPORT_SYMBOL(snd_card_new);
196
197 static void __snd_card_release(struct device *dev, void *data)
198 {
199 snd_card_free(data);
200 }
201
202 /**
203 * snd_devm_card_new - managed snd_card object creation
204 * @parent: the parent device object
205 * @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
206 * @xid: card identification (ASCII string)
207 * @module: top level module for locking
208 * @extra_size: allocate this extra size after the main soundcard structure
209 * @card_ret: the pointer to store the created card instance
210 *
211 * This function works like snd_card_new() but manages the allocated resource
212 * via devres, i.e. you don't need to free explicitly.
213 *
214 * When a snd_card object is created with this function and registered via
215 * snd_card_register(), the very first devres action to call snd_card_free()
216 * is added automatically. In that way, the resource disconnection is assured
217 * at first, then released in the expected order.
218 *
219 * If an error happens at the probe before snd_card_register() is called and
220 * there have been other devres resources, you'd need to free the card manually
221 * via snd_card_free() call in the error; otherwise it may lead to UAF due to
222 * devres call orders. You can use snd_card_free_on_error() helper for
223 * handling it more easily.
224 *
225 * Return: zero if successful, or a negative error code
226 */
227 int snd_devm_card_new(struct device *parent, int idx, const char *xid,
228 struct module *module, size_t extra_size,
229 struct snd_card **card_ret)
230 {
231 struct snd_card *card;
232 int err;
233
234 *card_ret = NULL;
235 card = devres_alloc(__snd_card_release, sizeof(*card) + extra_size,
236 GFP_KERNEL);
237 if (!card)
238 return -ENOMEM;
239 card->managed = true;
240 err = snd_card_init(card, parent, idx, xid, module, extra_size);
241 if (err < 0) {
242 devres_free(card); /* in managed mode, we need to free manually */
243 return err;
244 }
245
246 devres_add(parent, card);
247 *card_ret = card;
248 return 0;
249 }
250 EXPORT_SYMBOL_GPL(snd_devm_card_new);
251
252 /**
253 * snd_card_free_on_error - a small helper for handling devm probe errors
254 * @dev: the managed device object
255 * @ret: the return code from the probe callback
256 *
257 * This function handles the explicit snd_card_free() call at the error from
258 * the probe callback. It's just a small helper for simplifying the error
259 * handling with the managed devices.
260 *
261 * Return: zero if successful, or a negative error code
262 */
263 int snd_card_free_on_error(struct device *dev, int ret)
264 {
265 struct snd_card *card;
266
267 if (!ret)
268 return 0;
269 card = devres_find(dev, __snd_card_release, NULL, NULL);
270 if (card)
271 snd_card_free(card);
272 return ret;
273 }
274 EXPORT_SYMBOL_GPL(snd_card_free_on_error);
275
276 static int snd_card_init(struct snd_card *card, struct device *parent,
277 int idx, const char *xid, struct module *module,
278 size_t extra_size)
279 {
280 int err;
281
282 if (extra_size > 0)
283 card->private_data = (char *)card + sizeof(struct snd_card);
284 if (xid)
285 strscpy(card->id, xid, sizeof(card->id));
286 err = 0;
287 scoped_guard(mutex, &snd_card_mutex) {
288 if (idx < 0) /* first check the matching module-name slot */
289 idx = get_slot_from_bitmask(idx, module_slot_match, module);
290 if (idx < 0) /* if not matched, assign an empty slot */
291 idx = get_slot_from_bitmask(idx, check_empty_slot, module);
292 if (idx < 0)
293 err = -ENODEV;
294 else if (idx < snd_ecards_limit) {
295 if (test_bit(idx, snd_cards_lock))
296 err = -EBUSY; /* invalid */
297 } else if (idx >= SNDRV_CARDS)
298 err = -ENODEV;
299 if (!err) {
300 set_bit(idx, snd_cards_lock); /* lock it */
301 if (idx >= snd_ecards_limit)
302 snd_ecards_limit = idx + 1; /* increase the limit */
303 }
304 }
305 if (err < 0) {
306 dev_err(parent, "cannot find the slot for index %d (range 0-%i), error: %d\n",
307 idx, snd_ecards_limit - 1, err);
308 if (!card->managed)
309 kfree(card); /* manually free here, as no destructor called */
310 return err;
311 }
312 card->dev = parent;
313 card->number = idx;
314 WARN_ON(IS_MODULE(CONFIG_SND) && !module);
315 card->module = module;
316 INIT_LIST_HEAD(&card->devices);
317 init_rwsem(&card->controls_rwsem);
318 rwlock_init(&card->ctl_files_rwlock);
319 INIT_LIST_HEAD(&card->controls);
320 INIT_LIST_HEAD(&card->ctl_files);
321 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
322 xa_init(&card->ctl_numids);
323 xa_init(&card->ctl_hash);
324 #endif
325 spin_lock_init(&card->files_lock);
326 INIT_LIST_HEAD(&card->files_list);
327 mutex_init(&card->memory_mutex);
328 #ifdef CONFIG_PM
329 init_waitqueue_head(&card->power_sleep);
330 init_waitqueue_head(&card->power_ref_sleep);
331 atomic_set(&card->power_ref, 0);
332 #endif
333 init_waitqueue_head(&card->remove_sleep);
334 card->sync_irq = -1;
335
336 device_initialize(&card->card_dev);
337 card->card_dev.parent = parent;
338 card->card_dev.class = &sound_class;
339 card->card_dev.release = release_card_device;
340 card->card_dev.groups = card->dev_groups;
341 card->dev_groups[0] = &card_dev_attr_group;
342 err = kobject_set_name(&card->card_dev.kobj, "card%d", idx);
343 if (err < 0)
344 goto __error;
345
346 snprintf(card->irq_descr, sizeof(card->irq_descr), "%s:%s",
347 dev_driver_string(card->dev), dev_name(&card->card_dev));
348
349 /* the control interface cannot be accessed from the user space until */
350 /* snd_cards_bitmask and snd_cards are set with snd_card_register */
351 err = snd_ctl_create(card);
352 if (err < 0) {
353 dev_err(parent, "unable to register control minors\n");
354 goto __error;
355 }
356 err = snd_info_card_create(card);
357 if (err < 0) {
358 dev_err(parent, "unable to create card info\n");
359 goto __error_ctl;
360 }
361
362 #ifdef CONFIG_SND_DEBUG
363 card->debugfs_root = debugfs_create_dir(dev_name(&card->card_dev),
364 sound_debugfs_root);
365 #endif
366 return 0;
367
368 __error_ctl:
369 snd_device_free_all(card);
370 __error:
371 put_device(&card->card_dev);
372 return err;
373 }
374
375 /**
376 * snd_card_ref - Get the card object from the index
377 * @idx: the card index
378 *
379 * Returns a card object corresponding to the given index or NULL if not found.
380 * Release the object via snd_card_unref().
381 *
382 * Return: a card object or NULL
383 */
384 struct snd_card *snd_card_ref(int idx)
385 {
386 struct snd_card *card;
387
388 guard(mutex)(&snd_card_mutex);
389 card = snd_cards[idx];
390 if (card)
391 get_device(&card->card_dev);
392 return card;
393 }
394 EXPORT_SYMBOL_GPL(snd_card_ref);
395
396 /* return non-zero if a card is already locked */
397 int snd_card_locked(int card)
398 {
399 guard(mutex)(&snd_card_mutex);
400 return test_bit(card, snd_cards_lock);
401 }
402
403 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
404 {
405 return -ENODEV;
406 }
407
408 static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
409 size_t count, loff_t *offset)
410 {
411 return -ENODEV;
412 }
413
414 static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
415 size_t count, loff_t *offset)
416 {
417 return -ENODEV;
418 }
419
420 static int snd_disconnect_release(struct inode *inode, struct file *file)
421 {
422 struct snd_monitor_file *df = NULL, *_df;
423
424 scoped_guard(spinlock, &shutdown_lock) {
425 list_for_each_entry(_df, &shutdown_files, shutdown_list) {
426 if (_df->file == file) {
427 df = _df;
428 list_del_init(&df->shutdown_list);
429 break;
430 }
431 }
432 }
433
434 if (likely(df)) {
435 if ((file->f_flags & FASYNC) && df->disconnected_f_op->fasync)
436 df->disconnected_f_op->fasync(-1, file, 0);
437 return df->disconnected_f_op->release(inode, file);
438 }
439
440 panic("%s(%p, %p) failed!", __func__, inode, file);
441 }
442
443 static __poll_t snd_disconnect_poll(struct file * file, poll_table * wait)
444 {
445 return EPOLLERR | EPOLLNVAL;
446 }
447
448 static long snd_disconnect_ioctl(struct file *file,
449 unsigned int cmd, unsigned long arg)
450 {
451 return -ENODEV;
452 }
453
454 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
455 {
456 return -ENODEV;
457 }
458
459 static int snd_disconnect_fasync(int fd, struct file *file, int on)
460 {
461 return -ENODEV;
462 }
463
464 static const struct file_operations snd_shutdown_f_ops =
465 {
466 .owner = THIS_MODULE,
467 .llseek = snd_disconnect_llseek,
468 .read = snd_disconnect_read,
469 .write = snd_disconnect_write,
470 .release = snd_disconnect_release,
471 .poll = snd_disconnect_poll,
472 .unlocked_ioctl = snd_disconnect_ioctl,
473 #ifdef CONFIG_COMPAT
474 .compat_ioctl = snd_disconnect_ioctl,
475 #endif
476 .mmap = snd_disconnect_mmap,
477 .fasync = snd_disconnect_fasync
478 };
479
480 /**
481 * snd_card_disconnect - disconnect all APIs from the file-operations (user space)
482 * @card: soundcard structure
483 *
484 * Disconnects all APIs from the file-operations (user space).
485 *
486 * Return: Zero, otherwise a negative error code.
487 *
488 * Note: The current implementation replaces all active file->f_op with special
489 * dummy file operations (they do nothing except release).
490 */
491 void snd_card_disconnect(struct snd_card *card)
492 {
493 struct snd_monitor_file *mfile;
494
495 if (!card)
496 return;
497
498 scoped_guard(spinlock, &card->files_lock) {
499 if (card->shutdown)
500 return;
501 card->shutdown = 1;
502
503 /* replace file->f_op with special dummy operations */
504 list_for_each_entry(mfile, &card->files_list, list) {
505 /* it's critical part, use endless loop */
506 /* we have no room to fail */
507 mfile->disconnected_f_op = mfile->file->f_op;
508
509 scoped_guard(spinlock, &shutdown_lock)
510 list_add(&mfile->shutdown_list, &shutdown_files);
511
512 mfile->file->f_op = &snd_shutdown_f_ops;
513 fops_get(mfile->file->f_op);
514 }
515 }
516
517 #ifdef CONFIG_PM
518 /* wake up sleepers here before other callbacks for avoiding potential
519 * deadlocks with other locks (e.g. in kctls);
520 * then this notifies the shutdown and sleepers would abort immediately
521 */
522 wake_up_all(&card->power_sleep);
523 #endif
524
525 /* notify all connected devices about disconnection */
526 /* at this point, they cannot respond to any calls except release() */
527
528 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
529 if (snd_mixer_oss_notify_callback)
530 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
531 #endif
532
533 /* notify all devices that we are disconnected */
534 snd_device_disconnect_all(card);
535
536 if (card->sync_irq > 0)
537 synchronize_irq(card->sync_irq);
538
539 snd_info_card_disconnect(card);
540 #ifdef CONFIG_SND_DEBUG
541 debugfs_remove(card->debugfs_root);
542 card->debugfs_root = NULL;
543 #endif
544
545 if (card->registered) {
546 device_del(&card->card_dev);
547 card->registered = false;
548 }
549
550 /* disable fops (user space) operations for ALSA API */
551 scoped_guard(mutex, &snd_card_mutex) {
552 snd_cards[card->number] = NULL;
553 clear_bit(card->number, snd_cards_lock);
554 }
555
556 snd_power_sync_ref(card);
557 }
558 EXPORT_SYMBOL(snd_card_disconnect);
559
560 /**
561 * snd_card_disconnect_sync - disconnect card and wait until files get closed
562 * @card: card object to disconnect
563 *
564 * This calls snd_card_disconnect() for disconnecting all belonging components
565 * and waits until all pending files get closed.
566 * It assures that all accesses from user-space finished so that the driver
567 * can release its resources gracefully.
568 */
569 void snd_card_disconnect_sync(struct snd_card *card)
570 {
571 snd_card_disconnect(card);
572
573 guard(spinlock_irq)(&card->files_lock);
574 wait_event_lock_irq(card->remove_sleep,
575 list_empty(&card->files_list),
576 card->files_lock);
577 }
578 EXPORT_SYMBOL_GPL(snd_card_disconnect_sync);
579
580 static int snd_card_do_free(struct snd_card *card)
581 {
582 card->releasing = true;
583 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
584 if (snd_mixer_oss_notify_callback)
585 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
586 #endif
587 snd_device_free_all(card);
588 if (card->private_free)
589 card->private_free(card);
590 if (snd_info_card_free(card) < 0) {
591 dev_warn(card->dev, "unable to free card info\n");
592 /* Not fatal error */
593 }
594 if (card->release_completion)
595 complete(card->release_completion);
596 if (!card->managed)
597 kfree(card);
598 return 0;
599 }
600
601 /**
602 * snd_card_free_when_closed - Disconnect the card, free it later eventually
603 * @card: soundcard structure
604 *
605 * Unlike snd_card_free(), this function doesn't try to release the card
606 * resource immediately, but tries to disconnect at first. When the card
607 * is still in use, the function returns before freeing the resources.
608 * The card resources will be freed when the refcount gets to zero.
609 *
610 * Return: zero if successful, or a negative error code
611 */
612 void snd_card_free_when_closed(struct snd_card *card)
613 {
614 if (!card)
615 return;
616
617 snd_card_disconnect(card);
618 put_device(&card->card_dev);
619 return;
620 }
621 EXPORT_SYMBOL(snd_card_free_when_closed);
622
623 /**
624 * snd_card_free - frees given soundcard structure
625 * @card: soundcard structure
626 *
627 * This function releases the soundcard structure and the all assigned
628 * devices automatically. That is, you don't have to release the devices
629 * by yourself.
630 *
631 * This function waits until the all resources are properly released.
632 *
633 * Return: Zero. Frees all associated devices and frees the control
634 * interface associated to given soundcard.
635 */
636 void snd_card_free(struct snd_card *card)
637 {
638 DECLARE_COMPLETION_ONSTACK(released);
639
640 /* The call of snd_card_free() is allowed from various code paths;
641 * a manual call from the driver and the call via devres_free, and
642 * we need to avoid double-free. Moreover, the release via devres
643 * may call snd_card_free() twice due to its nature, we need to have
644 * the check here at the beginning.
645 */
646 if (card->releasing)
647 return;
648
649 card->release_completion = &released;
650 snd_card_free_when_closed(card);
651
652 /* wait, until all devices are ready for the free operation */
653 wait_for_completion(&released);
654 }
655 EXPORT_SYMBOL(snd_card_free);
656
657 /* check, if the character is in the valid ASCII range */
658 static inline bool safe_ascii_char(char c)
659 {
660 return isascii(c) && isalnum(c);
661 }
662
663 /* retrieve the last word of shortname or longname */
664 static const char *retrieve_id_from_card_name(const char *name)
665 {
666 const char *spos = name;
667
668 while (*name) {
669 if (isspace(*name) && safe_ascii_char(name[1]))
670 spos = name + 1;
671 name++;
672 }
673 return spos;
674 }
675
676 /* return true if the given id string doesn't conflict any other card ids */
677 static bool card_id_ok(struct snd_card *card, const char *id)
678 {
679 int i;
680 if (!snd_info_check_reserved_words(id))
681 return false;
682 for (i = 0; i < snd_ecards_limit; i++) {
683 if (snd_cards[i] && snd_cards[i] != card &&
684 !strcmp(snd_cards[i]->id, id))
685 return false;
686 }
687 return true;
688 }
689
690 /* copy to card->id only with valid letters from nid */
691 static void copy_valid_id_string(struct snd_card *card, const char *src,
692 const char *nid)
693 {
694 char *id = card->id;
695
696 while (*nid && !safe_ascii_char(*nid))
697 nid++;
698 if (isdigit(*nid))
699 *id++ = isalpha(*src) ? *src : 'D';
700 while (*nid && (size_t)(id - card->id) < sizeof(card->id) - 1) {
701 if (safe_ascii_char(*nid))
702 *id++ = *nid;
703 nid++;
704 }
705 *id = 0;
706 }
707
708 /* Set card->id from the given string
709 * If the string conflicts with other ids, add a suffix to make it unique.
710 */
711 static void snd_card_set_id_no_lock(struct snd_card *card, const char *src,
712 const char *nid)
713 {
714 int len, loops;
715 bool is_default = false;
716 char *id;
717
718 copy_valid_id_string(card, src, nid);
719 id = card->id;
720
721 again:
722 /* use "Default" for obviously invalid strings
723 * ("card" conflicts with proc directories)
724 */
725 if (!*id || !strncmp(id, "card", 4)) {
726 strcpy(id, "Default");
727 is_default = true;
728 }
729
730 len = strlen(id);
731 for (loops = 0; loops < SNDRV_CARDS; loops++) {
732 char *spos;
733 char sfxstr[5]; /* "_012" */
734 int sfxlen;
735
736 if (card_id_ok(card, id))
737 return; /* OK */
738
739 /* Add _XYZ suffix */
740 sprintf(sfxstr, "_%X", loops + 1);
741 sfxlen = strlen(sfxstr);
742 if (len + sfxlen >= sizeof(card->id))
743 spos = id + sizeof(card->id) - sfxlen - 1;
744 else
745 spos = id + len;
746 strcpy(spos, sfxstr);
747 }
748 /* fallback to the default id */
749 if (!is_default) {
750 *id = 0;
751 goto again;
752 }
753 /* last resort... */
754 dev_err(card->dev, "unable to set card id (%s)\n", id);
755 if (card->proc_root->name)
756 strscpy(card->id, card->proc_root->name, sizeof(card->id));
757 }
758
759 /**
760 * snd_card_set_id - set card identification name
761 * @card: soundcard structure
762 * @nid: new identification string
763 *
764 * This function sets the card identification and checks for name
765 * collisions.
766 */
767 void snd_card_set_id(struct snd_card *card, const char *nid)
768 {
769 /* check if user specified own card->id */
770 if (card->id[0] != '\0')
771 return;
772 guard(mutex)(&snd_card_mutex);
773 snd_card_set_id_no_lock(card, nid, nid);
774 }
775 EXPORT_SYMBOL(snd_card_set_id);
776
777 static ssize_t id_show(struct device *dev,
778 struct device_attribute *attr, char *buf)
779 {
780 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
781 return sysfs_emit(buf, "%s\n", card->id);
782 }
783
784 static ssize_t id_store(struct device *dev, struct device_attribute *attr,
785 const char *buf, size_t count)
786 {
787 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
788 char buf1[sizeof(card->id)];
789 size_t copy = count > sizeof(card->id) - 1 ?
790 sizeof(card->id) - 1 : count;
791 size_t idx;
792 int c;
793
794 for (idx = 0; idx < copy; idx++) {
795 c = buf[idx];
796 if (!safe_ascii_char(c) && c != '_' && c != '-')
797 return -EINVAL;
798 }
799 memcpy(buf1, buf, copy);
800 buf1[copy] = '\0';
801 guard(mutex)(&snd_card_mutex);
802 if (!card_id_ok(NULL, buf1))
803 return -EEXIST;
804 strcpy(card->id, buf1);
805 snd_info_card_id_change(card);
806
807 return count;
808 }
809
810 static DEVICE_ATTR_RW(id);
811
812 static ssize_t number_show(struct device *dev,
813 struct device_attribute *attr, char *buf)
814 {
815 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
816 return sysfs_emit(buf, "%i\n", card->number);
817 }
818
819 static DEVICE_ATTR_RO(number);
820
821 static struct attribute *card_dev_attrs[] = {
822 &dev_attr_id.attr,
823 &dev_attr_number.attr,
824 NULL
825 };
826
827 static const struct attribute_group card_dev_attr_group = {
828 .attrs = card_dev_attrs,
829 };
830
831 /**
832 * snd_card_add_dev_attr - Append a new sysfs attribute group to card
833 * @card: card instance
834 * @group: attribute group to append
835 *
836 * Return: zero if successful, or a negative error code
837 */
838 int snd_card_add_dev_attr(struct snd_card *card,
839 const struct attribute_group *group)
840 {
841 int i;
842
843 /* loop for (arraysize-1) here to keep NULL at the last entry */
844 for (i = 0; i < ARRAY_SIZE(card->dev_groups) - 1; i++) {
845 if (!card->dev_groups[i]) {
846 card->dev_groups[i] = group;
847 return 0;
848 }
849 }
850
851 dev_err(card->dev, "Too many groups assigned\n");
852 return -ENOSPC;
853 }
854 EXPORT_SYMBOL_GPL(snd_card_add_dev_attr);
855
856 static void trigger_card_free(void *data)
857 {
858 snd_card_free(data);
859 }
860
861 /**
862 * snd_card_register - register the soundcard
863 * @card: soundcard structure
864 *
865 * This function registers all the devices assigned to the soundcard.
866 * Until calling this, the ALSA control interface is blocked from the
867 * external accesses. Thus, you should call this function at the end
868 * of the initialization of the card.
869 *
870 * Return: Zero otherwise a negative error code if the registration failed.
871 */
872 int snd_card_register(struct snd_card *card)
873 {
874 int err;
875
876 if (snd_BUG_ON(!card))
877 return -EINVAL;
878
879 if (!card->registered) {
880 err = device_add(&card->card_dev);
881 if (err < 0)
882 return err;
883 card->registered = true;
884 } else {
885 if (card->managed)
886 devm_remove_action(card->dev, trigger_card_free, card);
887 }
888
889 if (card->managed) {
890 err = devm_add_action(card->dev, trigger_card_free, card);
891 if (err < 0)
892 return err;
893 }
894
895 err = snd_device_register_all(card);
896 if (err < 0)
897 return err;
898 scoped_guard(mutex, &snd_card_mutex) {
899 if (snd_cards[card->number]) {
900 /* already registered */
901 return snd_info_card_register(card); /* register pending info */
902 }
903 if (*card->id) {
904 /* make a unique id name from the given string */
905 char tmpid[sizeof(card->id)];
906
907 memcpy(tmpid, card->id, sizeof(card->id));
908 snd_card_set_id_no_lock(card, tmpid, tmpid);
909 } else {
910 /* create an id from either shortname or longname */
911 const char *src;
912
913 src = *card->shortname ? card->shortname : card->longname;
914 snd_card_set_id_no_lock(card, src,
915 retrieve_id_from_card_name(src));
916 }
917 snd_cards[card->number] = card;
918 }
919 err = snd_info_card_register(card);
920 if (err < 0)
921 return err;
922
923 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
924 if (snd_mixer_oss_notify_callback)
925 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
926 #endif
927 return 0;
928 }
929 EXPORT_SYMBOL(snd_card_register);
930
931 #ifdef CONFIG_SND_PROC_FS
932 static void snd_card_info_read(struct snd_info_entry *entry,
933 struct snd_info_buffer *buffer)
934 {
935 int idx, count;
936 struct snd_card *card;
937
938 for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
939 guard(mutex)(&snd_card_mutex);
940 card = snd_cards[idx];
941 if (card) {
942 count++;
943 snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
944 idx,
945 card->id,
946 card->driver,
947 card->shortname);
948 snd_iprintf(buffer, " %s\n",
949 card->longname);
950 }
951 }
952 if (!count)
953 snd_iprintf(buffer, "--- no soundcards ---\n");
954 }
955
956 #ifdef CONFIG_SND_OSSEMUL
957 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
958 {
959 int idx, count;
960 struct snd_card *card;
961
962 for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
963 guard(mutex)(&snd_card_mutex);
964 card = snd_cards[idx];
965 if (card) {
966 count++;
967 snd_iprintf(buffer, "%s\n", card->longname);
968 }
969 }
970 if (!count) {
971 snd_iprintf(buffer, "--- no soundcards ---\n");
972 }
973 }
974
975 #endif
976
977 #ifdef CONFIG_MODULES
978 static void snd_card_module_info_read(struct snd_info_entry *entry,
979 struct snd_info_buffer *buffer)
980 {
981 int idx;
982 struct snd_card *card;
983
984 for (idx = 0; idx < SNDRV_CARDS; idx++) {
985 guard(mutex)(&snd_card_mutex);
986 card = snd_cards[idx];
987 if (card)
988 snd_iprintf(buffer, "%2i %s\n",
989 idx, card->module->name);
990 }
991 }
992 #endif
993
994 int __init snd_card_info_init(void)
995 {
996 struct snd_info_entry *entry;
997
998 entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
999 if (! entry)
1000 return -ENOMEM;
1001 entry->c.text.read = snd_card_info_read;
1002 if (snd_info_register(entry) < 0)
1003 return -ENOMEM; /* freed in error path */
1004
1005 #ifdef CONFIG_MODULES
1006 entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
1007 if (!entry)
1008 return -ENOMEM;
1009 entry->c.text.read = snd_card_module_info_read;
1010 if (snd_info_register(entry) < 0)
1011 return -ENOMEM; /* freed in error path */
1012 #endif
1013
1014 return 0;
1015 }
1016 #endif /* CONFIG_SND_PROC_FS */
1017
1018 /**
1019 * snd_component_add - add a component string
1020 * @card: soundcard structure
1021 * @component: the component id string
1022 *
1023 * This function adds the component id string to the supported list.
1024 * The component can be referred from the alsa-lib.
1025 *
1026 * Return: Zero otherwise a negative error code.
1027 */
1028
1029 int snd_component_add(struct snd_card *card, const char *component)
1030 {
1031 char *ptr;
1032 int len = strlen(component);
1033
1034 ptr = strstr(card->components, component);
1035 if (ptr != NULL) {
1036 if (ptr[len] == '\0' || ptr[len] == ' ') /* already there */
1037 return 1;
1038 }
1039 if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
1040 snd_BUG();
1041 return -ENOMEM;
1042 }
1043 if (card->components[0] != '\0')
1044 strcat(card->components, " ");
1045 strcat(card->components, component);
1046 return 0;
1047 }
1048 EXPORT_SYMBOL(snd_component_add);
1049
1050 /**
1051 * snd_card_file_add - add the file to the file list of the card
1052 * @card: soundcard structure
1053 * @file: file pointer
1054 *
1055 * This function adds the file to the file linked-list of the card.
1056 * This linked-list is used to keep tracking the connection state,
1057 * and to avoid the release of busy resources by hotplug.
1058 *
1059 * Return: zero or a negative error code.
1060 */
1061 int snd_card_file_add(struct snd_card *card, struct file *file)
1062 {
1063 struct snd_monitor_file *mfile;
1064
1065 mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
1066 if (mfile == NULL)
1067 return -ENOMEM;
1068 mfile->file = file;
1069 mfile->disconnected_f_op = NULL;
1070 INIT_LIST_HEAD(&mfile->shutdown_list);
1071 guard(spinlock)(&card->files_lock);
1072 if (card->shutdown) {
1073 kfree(mfile);
1074 return -ENODEV;
1075 }
1076 list_add(&mfile->list, &card->files_list);
1077 get_device(&card->card_dev);
1078 return 0;
1079 }
1080 EXPORT_SYMBOL(snd_card_file_add);
1081
1082 /**
1083 * snd_card_file_remove - remove the file from the file list
1084 * @card: soundcard structure
1085 * @file: file pointer
1086 *
1087 * This function removes the file formerly added to the card via
1088 * snd_card_file_add() function.
1089 * If all files are removed and snd_card_free_when_closed() was
1090 * called beforehand, it processes the pending release of
1091 * resources.
1092 *
1093 * Return: Zero or a negative error code.
1094 */
1095 int snd_card_file_remove(struct snd_card *card, struct file *file)
1096 {
1097 struct snd_monitor_file *mfile, *found = NULL;
1098
1099 scoped_guard(spinlock, &card->files_lock) {
1100 list_for_each_entry(mfile, &card->files_list, list) {
1101 if (mfile->file == file) {
1102 list_del(&mfile->list);
1103 scoped_guard(spinlock, &shutdown_lock)
1104 list_del(&mfile->shutdown_list);
1105 if (mfile->disconnected_f_op)
1106 fops_put(mfile->disconnected_f_op);
1107 found = mfile;
1108 break;
1109 }
1110 }
1111 if (list_empty(&card->files_list))
1112 wake_up_all(&card->remove_sleep);
1113 }
1114 if (!found) {
1115 dev_err(card->dev, "card file remove problem (%p)\n", file);
1116 return -ENOENT;
1117 }
1118 kfree(found);
1119 put_device(&card->card_dev);
1120 return 0;
1121 }
1122 EXPORT_SYMBOL(snd_card_file_remove);
1123
1124 #ifdef CONFIG_PM
1125 /**
1126 * snd_power_ref_and_wait - wait until the card gets powered up
1127 * @card: soundcard structure
1128 *
1129 * Take the power_ref reference count of the given card, and
1130 * wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
1131 * The refcount is down again while sleeping until power-up, hence this
1132 * function can be used for syncing the floating control ops accesses,
1133 * typically around calling control ops.
1134 *
1135 * The caller needs to pull down the refcount via snd_power_unref() later
1136 * no matter whether the error is returned from this function or not.
1137 *
1138 * Return: Zero if successful, or a negative error code.
1139 */
1140 int snd_power_ref_and_wait(struct snd_card *card)
1141 {
1142 snd_power_ref(card);
1143 if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
1144 return 0;
1145 wait_event_cmd(card->power_sleep,
1146 card->shutdown ||
1147 snd_power_get_state(card) == SNDRV_CTL_POWER_D0,
1148 snd_power_unref(card), snd_power_ref(card));
1149 return card->shutdown ? -ENODEV : 0;
1150 }
1151 EXPORT_SYMBOL_GPL(snd_power_ref_and_wait);
1152
1153 /**
1154 * snd_power_wait - wait until the card gets powered up (old form)
1155 * @card: soundcard structure
1156 *
1157 * Wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
1158 *
1159 * Return: Zero if successful, or a negative error code.
1160 */
1161 int snd_power_wait(struct snd_card *card)
1162 {
1163 int ret;
1164
1165 ret = snd_power_ref_and_wait(card);
1166 snd_power_unref(card);
1167 return ret;
1168 }
1169 EXPORT_SYMBOL(snd_power_wait);
1170 #endif /* CONFIG_PM */
1171
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