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 */
module_slot_match(struct module * module,int idx)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
check_empty_slot(struct module * module,int slot)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 */
get_slot_from_bitmask(int mask,int (* check)(struct module *,int),struct module * module)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() */
default_release_alloc(struct device * dev)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 */
snd_device_alloc(struct device ** dev_p,struct snd_card * card)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
release_card_device(struct device * dev)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 */
snd_card_new(struct device * parent,int idx,const char * xid,struct module * module,int extra_size,struct snd_card ** card_ret)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
__snd_card_release(struct device * dev,void * data)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 */
snd_devm_card_new(struct device * parent,int idx,const char * xid,struct module * module,size_t extra_size,struct snd_card ** card_ret)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 */
snd_card_free_on_error(struct device * dev,int ret)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
snd_card_init(struct snd_card * card,struct device * parent,int idx,const char * xid,struct module * module,size_t extra_size)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 */
snd_card_ref(int idx)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 */
snd_card_locked(int card)397 int snd_card_locked(int card)
398 {
399 guard(mutex)(&snd_card_mutex);
400 return test_bit(card, snd_cards_lock);
401 }
402
snd_disconnect_llseek(struct file * file,loff_t offset,int orig)403 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
404 {
405 return -ENODEV;
406 }
407
snd_disconnect_read(struct file * file,char __user * buf,size_t count,loff_t * offset)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
snd_disconnect_write(struct file * file,const char __user * buf,size_t count,loff_t * offset)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
snd_disconnect_release(struct inode * inode,struct file * file)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
snd_disconnect_poll(struct file * file,poll_table * wait)443 static __poll_t snd_disconnect_poll(struct file * file, poll_table * wait)
444 {
445 return EPOLLERR | EPOLLNVAL;
446 }
447
snd_disconnect_ioctl(struct file * file,unsigned int cmd,unsigned long arg)448 static long snd_disconnect_ioctl(struct file *file,
449 unsigned int cmd, unsigned long arg)
450 {
451 return -ENODEV;
452 }
453
snd_disconnect_mmap(struct file * file,struct vm_area_struct * vma)454 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
455 {
456 return -ENODEV;
457 }
458
snd_disconnect_fasync(int fd,struct file * file,int on)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 */
snd_card_disconnect(struct snd_card * card)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 */
snd_card_disconnect_sync(struct snd_card * card)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
snd_card_do_free(struct snd_card * card)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 */
snd_card_free_when_closed(struct snd_card * card)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 */
snd_card_free(struct snd_card * card)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 /* retrieve the last word of shortname or longname */
retrieve_id_from_card_name(const char * name)658 static const char *retrieve_id_from_card_name(const char *name)
659 {
660 const char *spos = name;
661
662 while (*name) {
663 if (isspace(*name) && isalnum(name[1]))
664 spos = name + 1;
665 name++;
666 }
667 return spos;
668 }
669
670 /* return true if the given id string doesn't conflict any other card ids */
card_id_ok(struct snd_card * card,const char * id)671 static bool card_id_ok(struct snd_card *card, const char *id)
672 {
673 int i;
674 if (!snd_info_check_reserved_words(id))
675 return false;
676 for (i = 0; i < snd_ecards_limit; i++) {
677 if (snd_cards[i] && snd_cards[i] != card &&
678 !strcmp(snd_cards[i]->id, id))
679 return false;
680 }
681 return true;
682 }
683
684 /* copy to card->id only with valid letters from nid */
copy_valid_id_string(struct snd_card * card,const char * src,const char * nid)685 static void copy_valid_id_string(struct snd_card *card, const char *src,
686 const char *nid)
687 {
688 char *id = card->id;
689
690 while (*nid && !isalnum(*nid))
691 nid++;
692 if (isdigit(*nid))
693 *id++ = isalpha(*src) ? *src : 'D';
694 while (*nid && (size_t)(id - card->id) < sizeof(card->id) - 1) {
695 if (isalnum(*nid))
696 *id++ = *nid;
697 nid++;
698 }
699 *id = 0;
700 }
701
702 /* Set card->id from the given string
703 * If the string conflicts with other ids, add a suffix to make it unique.
704 */
snd_card_set_id_no_lock(struct snd_card * card,const char * src,const char * nid)705 static void snd_card_set_id_no_lock(struct snd_card *card, const char *src,
706 const char *nid)
707 {
708 int len, loops;
709 bool is_default = false;
710 char *id;
711
712 copy_valid_id_string(card, src, nid);
713 id = card->id;
714
715 again:
716 /* use "Default" for obviously invalid strings
717 * ("card" conflicts with proc directories)
718 */
719 if (!*id || !strncmp(id, "card", 4)) {
720 strcpy(id, "Default");
721 is_default = true;
722 }
723
724 len = strlen(id);
725 for (loops = 0; loops < SNDRV_CARDS; loops++) {
726 char *spos;
727 char sfxstr[5]; /* "_012" */
728 int sfxlen;
729
730 if (card_id_ok(card, id))
731 return; /* OK */
732
733 /* Add _XYZ suffix */
734 sprintf(sfxstr, "_%X", loops + 1);
735 sfxlen = strlen(sfxstr);
736 if (len + sfxlen >= sizeof(card->id))
737 spos = id + sizeof(card->id) - sfxlen - 1;
738 else
739 spos = id + len;
740 strcpy(spos, sfxstr);
741 }
742 /* fallback to the default id */
743 if (!is_default) {
744 *id = 0;
745 goto again;
746 }
747 /* last resort... */
748 dev_err(card->dev, "unable to set card id (%s)\n", id);
749 if (card->proc_root->name)
750 strscpy(card->id, card->proc_root->name, sizeof(card->id));
751 }
752
753 /**
754 * snd_card_set_id - set card identification name
755 * @card: soundcard structure
756 * @nid: new identification string
757 *
758 * This function sets the card identification and checks for name
759 * collisions.
760 */
snd_card_set_id(struct snd_card * card,const char * nid)761 void snd_card_set_id(struct snd_card *card, const char *nid)
762 {
763 /* check if user specified own card->id */
764 if (card->id[0] != '\0')
765 return;
766 guard(mutex)(&snd_card_mutex);
767 snd_card_set_id_no_lock(card, nid, nid);
768 }
769 EXPORT_SYMBOL(snd_card_set_id);
770
id_show(struct device * dev,struct device_attribute * attr,char * buf)771 static ssize_t id_show(struct device *dev,
772 struct device_attribute *attr, char *buf)
773 {
774 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
775 return sysfs_emit(buf, "%s\n", card->id);
776 }
777
id_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)778 static ssize_t id_store(struct device *dev, struct device_attribute *attr,
779 const char *buf, size_t count)
780 {
781 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
782 char buf1[sizeof(card->id)];
783 size_t copy = count > sizeof(card->id) - 1 ?
784 sizeof(card->id) - 1 : count;
785 size_t idx;
786 int c;
787
788 for (idx = 0; idx < copy; idx++) {
789 c = buf[idx];
790 if (!isalnum(c) && c != '_' && c != '-')
791 return -EINVAL;
792 }
793 memcpy(buf1, buf, copy);
794 buf1[copy] = '\0';
795 guard(mutex)(&snd_card_mutex);
796 if (!card_id_ok(NULL, buf1))
797 return -EEXIST;
798 strcpy(card->id, buf1);
799 snd_info_card_id_change(card);
800
801 return count;
802 }
803
804 static DEVICE_ATTR_RW(id);
805
number_show(struct device * dev,struct device_attribute * attr,char * buf)806 static ssize_t number_show(struct device *dev,
807 struct device_attribute *attr, char *buf)
808 {
809 struct snd_card *card = container_of(dev, struct snd_card, card_dev);
810 return sysfs_emit(buf, "%i\n", card->number);
811 }
812
813 static DEVICE_ATTR_RO(number);
814
815 static struct attribute *card_dev_attrs[] = {
816 &dev_attr_id.attr,
817 &dev_attr_number.attr,
818 NULL
819 };
820
821 static const struct attribute_group card_dev_attr_group = {
822 .attrs = card_dev_attrs,
823 };
824
825 /**
826 * snd_card_add_dev_attr - Append a new sysfs attribute group to card
827 * @card: card instance
828 * @group: attribute group to append
829 *
830 * Return: zero if successful, or a negative error code
831 */
snd_card_add_dev_attr(struct snd_card * card,const struct attribute_group * group)832 int snd_card_add_dev_attr(struct snd_card *card,
833 const struct attribute_group *group)
834 {
835 int i;
836
837 /* loop for (arraysize-1) here to keep NULL at the last entry */
838 for (i = 0; i < ARRAY_SIZE(card->dev_groups) - 1; i++) {
839 if (!card->dev_groups[i]) {
840 card->dev_groups[i] = group;
841 return 0;
842 }
843 }
844
845 dev_err(card->dev, "Too many groups assigned\n");
846 return -ENOSPC;
847 }
848 EXPORT_SYMBOL_GPL(snd_card_add_dev_attr);
849
trigger_card_free(void * data)850 static void trigger_card_free(void *data)
851 {
852 snd_card_free(data);
853 }
854
855 /**
856 * snd_card_register - register the soundcard
857 * @card: soundcard structure
858 *
859 * This function registers all the devices assigned to the soundcard.
860 * Until calling this, the ALSA control interface is blocked from the
861 * external accesses. Thus, you should call this function at the end
862 * of the initialization of the card.
863 *
864 * Return: Zero otherwise a negative error code if the registration failed.
865 */
snd_card_register(struct snd_card * card)866 int snd_card_register(struct snd_card *card)
867 {
868 int err;
869
870 if (snd_BUG_ON(!card))
871 return -EINVAL;
872
873 if (!card->registered) {
874 err = device_add(&card->card_dev);
875 if (err < 0)
876 return err;
877 card->registered = true;
878 } else {
879 if (card->managed)
880 devm_remove_action(card->dev, trigger_card_free, card);
881 }
882
883 if (card->managed) {
884 err = devm_add_action(card->dev, trigger_card_free, card);
885 if (err < 0)
886 return err;
887 }
888
889 err = snd_device_register_all(card);
890 if (err < 0)
891 return err;
892 scoped_guard(mutex, &snd_card_mutex) {
893 if (snd_cards[card->number]) {
894 /* already registered */
895 return snd_info_card_register(card); /* register pending info */
896 }
897 if (*card->id) {
898 /* make a unique id name from the given string */
899 char tmpid[sizeof(card->id)];
900
901 memcpy(tmpid, card->id, sizeof(card->id));
902 snd_card_set_id_no_lock(card, tmpid, tmpid);
903 } else {
904 /* create an id from either shortname or longname */
905 const char *src;
906
907 src = *card->shortname ? card->shortname : card->longname;
908 snd_card_set_id_no_lock(card, src,
909 retrieve_id_from_card_name(src));
910 }
911 snd_cards[card->number] = card;
912 }
913 err = snd_info_card_register(card);
914 if (err < 0)
915 return err;
916
917 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
918 if (snd_mixer_oss_notify_callback)
919 snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
920 #endif
921 return 0;
922 }
923 EXPORT_SYMBOL(snd_card_register);
924
925 #ifdef CONFIG_SND_PROC_FS
snd_card_info_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)926 static void snd_card_info_read(struct snd_info_entry *entry,
927 struct snd_info_buffer *buffer)
928 {
929 int idx, count;
930 struct snd_card *card;
931
932 for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
933 guard(mutex)(&snd_card_mutex);
934 card = snd_cards[idx];
935 if (card) {
936 count++;
937 snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
938 idx,
939 card->id,
940 card->driver,
941 card->shortname);
942 snd_iprintf(buffer, " %s\n",
943 card->longname);
944 }
945 }
946 if (!count)
947 snd_iprintf(buffer, "--- no soundcards ---\n");
948 }
949
950 #ifdef CONFIG_SND_OSSEMUL
snd_card_info_read_oss(struct snd_info_buffer * buffer)951 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
952 {
953 int idx, count;
954 struct snd_card *card;
955
956 for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
957 guard(mutex)(&snd_card_mutex);
958 card = snd_cards[idx];
959 if (card) {
960 count++;
961 snd_iprintf(buffer, "%s\n", card->longname);
962 }
963 }
964 if (!count) {
965 snd_iprintf(buffer, "--- no soundcards ---\n");
966 }
967 }
968
969 #endif
970
971 #ifdef CONFIG_MODULES
snd_card_module_info_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)972 static void snd_card_module_info_read(struct snd_info_entry *entry,
973 struct snd_info_buffer *buffer)
974 {
975 int idx;
976 struct snd_card *card;
977
978 for (idx = 0; idx < SNDRV_CARDS; idx++) {
979 guard(mutex)(&snd_card_mutex);
980 card = snd_cards[idx];
981 if (card)
982 snd_iprintf(buffer, "%2i %s\n",
983 idx, card->module->name);
984 }
985 }
986 #endif
987
snd_card_info_init(void)988 int __init snd_card_info_init(void)
989 {
990 struct snd_info_entry *entry;
991
992 entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
993 if (! entry)
994 return -ENOMEM;
995 entry->c.text.read = snd_card_info_read;
996 if (snd_info_register(entry) < 0)
997 return -ENOMEM; /* freed in error path */
998
999 #ifdef CONFIG_MODULES
1000 entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
1001 if (!entry)
1002 return -ENOMEM;
1003 entry->c.text.read = snd_card_module_info_read;
1004 if (snd_info_register(entry) < 0)
1005 return -ENOMEM; /* freed in error path */
1006 #endif
1007
1008 return 0;
1009 }
1010 #endif /* CONFIG_SND_PROC_FS */
1011
1012 /**
1013 * snd_component_add - add a component string
1014 * @card: soundcard structure
1015 * @component: the component id string
1016 *
1017 * This function adds the component id string to the supported list.
1018 * The component can be referred from the alsa-lib.
1019 *
1020 * Return: Zero otherwise a negative error code.
1021 */
1022
snd_component_add(struct snd_card * card,const char * component)1023 int snd_component_add(struct snd_card *card, const char *component)
1024 {
1025 char *ptr;
1026 int len = strlen(component);
1027
1028 ptr = strstr(card->components, component);
1029 if (ptr != NULL) {
1030 if (ptr[len] == '\0' || ptr[len] == ' ') /* already there */
1031 return 1;
1032 }
1033 if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
1034 snd_BUG();
1035 return -ENOMEM;
1036 }
1037 if (card->components[0] != '\0')
1038 strcat(card->components, " ");
1039 strcat(card->components, component);
1040 return 0;
1041 }
1042 EXPORT_SYMBOL(snd_component_add);
1043
1044 /**
1045 * snd_card_file_add - add the file to the file list of the card
1046 * @card: soundcard structure
1047 * @file: file pointer
1048 *
1049 * This function adds the file to the file linked-list of the card.
1050 * This linked-list is used to keep tracking the connection state,
1051 * and to avoid the release of busy resources by hotplug.
1052 *
1053 * Return: zero or a negative error code.
1054 */
snd_card_file_add(struct snd_card * card,struct file * file)1055 int snd_card_file_add(struct snd_card *card, struct file *file)
1056 {
1057 struct snd_monitor_file *mfile;
1058
1059 mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
1060 if (mfile == NULL)
1061 return -ENOMEM;
1062 mfile->file = file;
1063 mfile->disconnected_f_op = NULL;
1064 INIT_LIST_HEAD(&mfile->shutdown_list);
1065 guard(spinlock)(&card->files_lock);
1066 if (card->shutdown) {
1067 kfree(mfile);
1068 return -ENODEV;
1069 }
1070 list_add(&mfile->list, &card->files_list);
1071 get_device(&card->card_dev);
1072 return 0;
1073 }
1074 EXPORT_SYMBOL(snd_card_file_add);
1075
1076 /**
1077 * snd_card_file_remove - remove the file from the file list
1078 * @card: soundcard structure
1079 * @file: file pointer
1080 *
1081 * This function removes the file formerly added to the card via
1082 * snd_card_file_add() function.
1083 * If all files are removed and snd_card_free_when_closed() was
1084 * called beforehand, it processes the pending release of
1085 * resources.
1086 *
1087 * Return: Zero or a negative error code.
1088 */
snd_card_file_remove(struct snd_card * card,struct file * file)1089 int snd_card_file_remove(struct snd_card *card, struct file *file)
1090 {
1091 struct snd_monitor_file *mfile, *found = NULL;
1092
1093 scoped_guard(spinlock, &card->files_lock) {
1094 list_for_each_entry(mfile, &card->files_list, list) {
1095 if (mfile->file == file) {
1096 list_del(&mfile->list);
1097 scoped_guard(spinlock, &shutdown_lock)
1098 list_del(&mfile->shutdown_list);
1099 if (mfile->disconnected_f_op)
1100 fops_put(mfile->disconnected_f_op);
1101 found = mfile;
1102 break;
1103 }
1104 }
1105 if (list_empty(&card->files_list))
1106 wake_up_all(&card->remove_sleep);
1107 }
1108 if (!found) {
1109 dev_err(card->dev, "card file remove problem (%p)\n", file);
1110 return -ENOENT;
1111 }
1112 kfree(found);
1113 put_device(&card->card_dev);
1114 return 0;
1115 }
1116 EXPORT_SYMBOL(snd_card_file_remove);
1117
1118 #ifdef CONFIG_PM
1119 /**
1120 * snd_power_ref_and_wait - wait until the card gets powered up
1121 * @card: soundcard structure
1122 *
1123 * Take the power_ref reference count of the given card, and
1124 * wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
1125 * The refcount is down again while sleeping until power-up, hence this
1126 * function can be used for syncing the floating control ops accesses,
1127 * typically around calling control ops.
1128 *
1129 * The caller needs to pull down the refcount via snd_power_unref() later
1130 * no matter whether the error is returned from this function or not.
1131 *
1132 * Return: Zero if successful, or a negative error code.
1133 */
snd_power_ref_and_wait(struct snd_card * card)1134 int snd_power_ref_and_wait(struct snd_card *card)
1135 {
1136 snd_power_ref(card);
1137 if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
1138 return 0;
1139 wait_event_cmd(card->power_sleep,
1140 card->shutdown ||
1141 snd_power_get_state(card) == SNDRV_CTL_POWER_D0,
1142 snd_power_unref(card), snd_power_ref(card));
1143 return card->shutdown ? -ENODEV : 0;
1144 }
1145 EXPORT_SYMBOL_GPL(snd_power_ref_and_wait);
1146
1147 /**
1148 * snd_power_wait - wait until the card gets powered up (old form)
1149 * @card: soundcard structure
1150 *
1151 * Wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
1152 *
1153 * Return: Zero if successful, or a negative error code.
1154 */
snd_power_wait(struct snd_card * card)1155 int snd_power_wait(struct snd_card *card)
1156 {
1157 int ret;
1158
1159 ret = snd_power_ref_and_wait(card);
1160 snd_power_unref(card);
1161 return ret;
1162 }
1163 EXPORT_SYMBOL(snd_power_wait);
1164 #endif /* CONFIG_PM */
1165