1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Advanced Linux Sound Architecture |
4 | * Copyright (c) by Jaroslav Kysela <perex@perex.cz> |
5 | */ |
6 | |
7 | #include <linux/init.h> |
8 | #include <linux/slab.h> |
9 | #include <linux/time.h> |
10 | #include <linux/device.h> |
11 | #include <linux/module.h> |
12 | #include <linux/debugfs.h> |
13 | #include <sound/core.h> |
14 | #include <sound/minors.h> |
15 | #include <sound/info.h> |
16 | #include <sound/control.h> |
17 | #include <sound/initval.h> |
18 | #include <linux/kmod.h> |
19 | #include <linux/mutex.h> |
20 | |
21 | static int major = CONFIG_SND_MAJOR; |
22 | int snd_major; |
23 | EXPORT_SYMBOL(snd_major); |
24 | |
25 | static int cards_limit = 1; |
26 | |
27 | MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>" ); |
28 | MODULE_DESCRIPTION("Advanced Linux Sound Architecture driver for soundcards." ); |
29 | MODULE_LICENSE("GPL" ); |
30 | module_param(major, int, 0444); |
31 | MODULE_PARM_DESC(major, "Major # for sound driver." ); |
32 | module_param(cards_limit, int, 0444); |
33 | MODULE_PARM_DESC(cards_limit, "Count of auto-loadable soundcards." ); |
34 | MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR); |
35 | |
36 | /* this one holds the actual max. card number currently available. |
37 | * as default, it's identical with cards_limit option. when more |
38 | * modules are loaded manually, this limit number increases, too. |
39 | */ |
40 | int snd_ecards_limit; |
41 | EXPORT_SYMBOL(snd_ecards_limit); |
42 | |
43 | #ifdef CONFIG_SND_DEBUG |
44 | struct dentry *sound_debugfs_root; |
45 | EXPORT_SYMBOL_GPL(sound_debugfs_root); |
46 | #endif |
47 | |
48 | static struct snd_minor *snd_minors[SNDRV_OS_MINORS]; |
49 | static DEFINE_MUTEX(sound_mutex); |
50 | |
51 | #ifdef CONFIG_MODULES |
52 | |
53 | /** |
54 | * snd_request_card - try to load the card module |
55 | * @card: the card number |
56 | * |
57 | * Tries to load the module "snd-card-X" for the given card number |
58 | * via request_module. Returns immediately if already loaded. |
59 | */ |
60 | void snd_request_card(int card) |
61 | { |
62 | if (snd_card_locked(card)) |
63 | return; |
64 | if (card < 0 || card >= cards_limit) |
65 | return; |
66 | request_module("snd-card-%i" , card); |
67 | } |
68 | EXPORT_SYMBOL(snd_request_card); |
69 | |
70 | static void snd_request_other(int minor) |
71 | { |
72 | char *str; |
73 | |
74 | switch (minor) { |
75 | case SNDRV_MINOR_SEQUENCER: str = "snd-seq" ; break; |
76 | case SNDRV_MINOR_TIMER: str = "snd-timer" ; break; |
77 | default: return; |
78 | } |
79 | request_module(str); |
80 | } |
81 | |
82 | #endif /* modular kernel */ |
83 | |
84 | /** |
85 | * snd_lookup_minor_data - get user data of a registered device |
86 | * @minor: the minor number |
87 | * @type: device type (SNDRV_DEVICE_TYPE_XXX) |
88 | * |
89 | * Checks that a minor device with the specified type is registered, and returns |
90 | * its user data pointer. |
91 | * |
92 | * This function increments the reference counter of the card instance |
93 | * if an associated instance with the given minor number and type is found. |
94 | * The caller must call snd_card_unref() appropriately later. |
95 | * |
96 | * Return: The user data pointer if the specified device is found. %NULL |
97 | * otherwise. |
98 | */ |
99 | void *snd_lookup_minor_data(unsigned int minor, int type) |
100 | { |
101 | struct snd_minor *mreg; |
102 | void *private_data; |
103 | |
104 | if (minor >= ARRAY_SIZE(snd_minors)) |
105 | return NULL; |
106 | guard(mutex)(T: &sound_mutex); |
107 | mreg = snd_minors[minor]; |
108 | if (mreg && mreg->type == type) { |
109 | private_data = mreg->private_data; |
110 | if (private_data && mreg->card_ptr) |
111 | get_device(dev: &mreg->card_ptr->card_dev); |
112 | } else |
113 | private_data = NULL; |
114 | return private_data; |
115 | } |
116 | EXPORT_SYMBOL(snd_lookup_minor_data); |
117 | |
118 | #ifdef CONFIG_MODULES |
119 | static struct snd_minor *autoload_device(unsigned int minor) |
120 | { |
121 | int dev; |
122 | mutex_unlock(lock: &sound_mutex); /* release lock temporarily */ |
123 | dev = SNDRV_MINOR_DEVICE(minor); |
124 | if (dev == SNDRV_MINOR_CONTROL) { |
125 | /* /dev/aloadC? */ |
126 | int card = SNDRV_MINOR_CARD(minor); |
127 | struct snd_card *ref = snd_card_ref(card); |
128 | if (!ref) |
129 | snd_request_card(card); |
130 | else |
131 | snd_card_unref(card: ref); |
132 | } else if (dev == SNDRV_MINOR_GLOBAL) { |
133 | /* /dev/aloadSEQ */ |
134 | snd_request_other(minor); |
135 | } |
136 | mutex_lock(&sound_mutex); /* reacuire lock */ |
137 | return snd_minors[minor]; |
138 | } |
139 | #else /* !CONFIG_MODULES */ |
140 | #define autoload_device(minor) NULL |
141 | #endif /* CONFIG_MODULES */ |
142 | |
143 | static int snd_open(struct inode *inode, struct file *file) |
144 | { |
145 | unsigned int minor = iminor(inode); |
146 | struct snd_minor *mptr = NULL; |
147 | const struct file_operations *new_fops; |
148 | int err = 0; |
149 | |
150 | if (minor >= ARRAY_SIZE(snd_minors)) |
151 | return -ENODEV; |
152 | scoped_guard(mutex, &sound_mutex) { |
153 | mptr = snd_minors[minor]; |
154 | if (mptr == NULL) { |
155 | mptr = autoload_device(minor); |
156 | if (!mptr) |
157 | return -ENODEV; |
158 | } |
159 | new_fops = fops_get(mptr->f_ops); |
160 | } |
161 | if (!new_fops) |
162 | return -ENODEV; |
163 | replace_fops(file, new_fops); |
164 | |
165 | if (file->f_op->open) |
166 | err = file->f_op->open(inode, file); |
167 | return err; |
168 | } |
169 | |
170 | static const struct file_operations snd_fops = |
171 | { |
172 | .owner = THIS_MODULE, |
173 | .open = snd_open, |
174 | .llseek = noop_llseek, |
175 | }; |
176 | |
177 | #ifdef CONFIG_SND_DYNAMIC_MINORS |
178 | static int snd_find_free_minor(int type, struct snd_card *card, int dev) |
179 | { |
180 | int minor; |
181 | |
182 | /* static minors for module auto loading */ |
183 | if (type == SNDRV_DEVICE_TYPE_SEQUENCER) |
184 | return SNDRV_MINOR_SEQUENCER; |
185 | if (type == SNDRV_DEVICE_TYPE_TIMER) |
186 | return SNDRV_MINOR_TIMER; |
187 | |
188 | for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) { |
189 | /* skip static minors still used for module auto loading */ |
190 | if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL) |
191 | continue; |
192 | if (minor == SNDRV_MINOR_SEQUENCER || |
193 | minor == SNDRV_MINOR_TIMER) |
194 | continue; |
195 | if (!snd_minors[minor]) |
196 | return minor; |
197 | } |
198 | return -EBUSY; |
199 | } |
200 | #else |
201 | static int snd_find_free_minor(int type, struct snd_card *card, int dev) |
202 | { |
203 | int minor; |
204 | |
205 | switch (type) { |
206 | case SNDRV_DEVICE_TYPE_SEQUENCER: |
207 | case SNDRV_DEVICE_TYPE_TIMER: |
208 | minor = type; |
209 | break; |
210 | case SNDRV_DEVICE_TYPE_CONTROL: |
211 | if (snd_BUG_ON(!card)) |
212 | return -EINVAL; |
213 | minor = SNDRV_MINOR(card->number, type); |
214 | break; |
215 | case SNDRV_DEVICE_TYPE_HWDEP: |
216 | case SNDRV_DEVICE_TYPE_RAWMIDI: |
217 | case SNDRV_DEVICE_TYPE_PCM_PLAYBACK: |
218 | case SNDRV_DEVICE_TYPE_PCM_CAPTURE: |
219 | case SNDRV_DEVICE_TYPE_COMPRESS: |
220 | if (snd_BUG_ON(!card)) |
221 | return -EINVAL; |
222 | minor = SNDRV_MINOR(card->number, type + dev); |
223 | break; |
224 | default: |
225 | return -EINVAL; |
226 | } |
227 | if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS)) |
228 | return -EINVAL; |
229 | if (snd_minors[minor]) |
230 | return -EBUSY; |
231 | return minor; |
232 | } |
233 | #endif |
234 | |
235 | /** |
236 | * snd_register_device - Register the ALSA device file for the card |
237 | * @type: the device type, SNDRV_DEVICE_TYPE_XXX |
238 | * @card: the card instance |
239 | * @dev: the device index |
240 | * @f_ops: the file operations |
241 | * @private_data: user pointer for f_ops->open() |
242 | * @device: the device to register |
243 | * |
244 | * Registers an ALSA device file for the given card. |
245 | * The operators have to be set in reg parameter. |
246 | * |
247 | * Return: Zero if successful, or a negative error code on failure. |
248 | */ |
249 | int snd_register_device(int type, struct snd_card *card, int dev, |
250 | const struct file_operations *f_ops, |
251 | void *private_data, struct device *device) |
252 | { |
253 | int minor; |
254 | int err = 0; |
255 | struct snd_minor *preg; |
256 | |
257 | if (snd_BUG_ON(!device)) |
258 | return -EINVAL; |
259 | |
260 | preg = kmalloc(size: sizeof *preg, GFP_KERNEL); |
261 | if (preg == NULL) |
262 | return -ENOMEM; |
263 | preg->type = type; |
264 | preg->card = card ? card->number : -1; |
265 | preg->device = dev; |
266 | preg->f_ops = f_ops; |
267 | preg->private_data = private_data; |
268 | preg->card_ptr = card; |
269 | guard(mutex)(T: &sound_mutex); |
270 | minor = snd_find_free_minor(type, card, dev); |
271 | if (minor < 0) { |
272 | err = minor; |
273 | goto error; |
274 | } |
275 | |
276 | preg->dev = device; |
277 | device->devt = MKDEV(major, minor); |
278 | err = device_add(dev: device); |
279 | if (err < 0) |
280 | goto error; |
281 | |
282 | snd_minors[minor] = preg; |
283 | error: |
284 | if (err < 0) |
285 | kfree(objp: preg); |
286 | return err; |
287 | } |
288 | EXPORT_SYMBOL(snd_register_device); |
289 | |
290 | /** |
291 | * snd_unregister_device - unregister the device on the given card |
292 | * @dev: the device instance |
293 | * |
294 | * Unregisters the device file already registered via |
295 | * snd_register_device(). |
296 | * |
297 | * Return: Zero if successful, or a negative error code on failure. |
298 | */ |
299 | int snd_unregister_device(struct device *dev) |
300 | { |
301 | int minor; |
302 | struct snd_minor *preg; |
303 | |
304 | guard(mutex)(T: &sound_mutex); |
305 | for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) { |
306 | preg = snd_minors[minor]; |
307 | if (preg && preg->dev == dev) { |
308 | snd_minors[minor] = NULL; |
309 | device_del(dev); |
310 | kfree(objp: preg); |
311 | break; |
312 | } |
313 | } |
314 | if (minor >= ARRAY_SIZE(snd_minors)) |
315 | return -ENOENT; |
316 | return 0; |
317 | } |
318 | EXPORT_SYMBOL(snd_unregister_device); |
319 | |
320 | #ifdef CONFIG_SND_PROC_FS |
321 | /* |
322 | * INFO PART |
323 | */ |
324 | static const char *snd_device_type_name(int type) |
325 | { |
326 | switch (type) { |
327 | case SNDRV_DEVICE_TYPE_CONTROL: |
328 | return "control" ; |
329 | case SNDRV_DEVICE_TYPE_HWDEP: |
330 | return "hardware dependent" ; |
331 | case SNDRV_DEVICE_TYPE_RAWMIDI: |
332 | return "raw midi" ; |
333 | case SNDRV_DEVICE_TYPE_PCM_PLAYBACK: |
334 | return "digital audio playback" ; |
335 | case SNDRV_DEVICE_TYPE_PCM_CAPTURE: |
336 | return "digital audio capture" ; |
337 | case SNDRV_DEVICE_TYPE_SEQUENCER: |
338 | return "sequencer" ; |
339 | case SNDRV_DEVICE_TYPE_TIMER: |
340 | return "timer" ; |
341 | case SNDRV_DEVICE_TYPE_COMPRESS: |
342 | return "compress" ; |
343 | default: |
344 | return "?" ; |
345 | } |
346 | } |
347 | |
348 | static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer) |
349 | { |
350 | int minor; |
351 | struct snd_minor *mptr; |
352 | |
353 | guard(mutex)(T: &sound_mutex); |
354 | for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) { |
355 | mptr = snd_minors[minor]; |
356 | if (!mptr) |
357 | continue; |
358 | if (mptr->card >= 0) { |
359 | if (mptr->device >= 0) |
360 | snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n" , |
361 | minor, mptr->card, mptr->device, |
362 | snd_device_type_name(mptr->type)); |
363 | else |
364 | snd_iprintf(buffer, "%3i: [%2i] : %s\n" , |
365 | minor, mptr->card, |
366 | snd_device_type_name(mptr->type)); |
367 | } else |
368 | snd_iprintf(buffer, "%3i: : %s\n" , minor, |
369 | snd_device_type_name(mptr->type)); |
370 | } |
371 | } |
372 | |
373 | int __init snd_minor_info_init(void) |
374 | { |
375 | struct snd_info_entry *entry; |
376 | |
377 | entry = snd_info_create_module_entry(THIS_MODULE, name: "devices" , NULL); |
378 | if (!entry) |
379 | return -ENOMEM; |
380 | entry->c.text.read = snd_minor_info_read; |
381 | return snd_info_register(entry); /* freed in error path */ |
382 | } |
383 | #endif /* CONFIG_SND_PROC_FS */ |
384 | |
385 | /* |
386 | * INIT PART |
387 | */ |
388 | |
389 | static int __init alsa_sound_init(void) |
390 | { |
391 | snd_major = major; |
392 | snd_ecards_limit = cards_limit; |
393 | if (register_chrdev(major, name: "alsa" , fops: &snd_fops)) { |
394 | pr_err("ALSA core: unable to register native major device number %d\n" , major); |
395 | return -EIO; |
396 | } |
397 | if (snd_info_init() < 0) { |
398 | unregister_chrdev(major, name: "alsa" ); |
399 | return -ENOMEM; |
400 | } |
401 | |
402 | #ifdef CONFIG_SND_DEBUG |
403 | sound_debugfs_root = debugfs_create_dir(name: "sound" , NULL); |
404 | #endif |
405 | #ifndef MODULE |
406 | pr_info("Advanced Linux Sound Architecture Driver Initialized.\n" ); |
407 | #endif |
408 | return 0; |
409 | } |
410 | |
411 | static void __exit alsa_sound_exit(void) |
412 | { |
413 | #ifdef CONFIG_SND_DEBUG |
414 | debugfs_remove(dentry: sound_debugfs_root); |
415 | #endif |
416 | snd_info_done(); |
417 | unregister_chrdev(major, name: "alsa" ); |
418 | } |
419 | |
420 | subsys_initcall(alsa_sound_init); |
421 | module_exit(alsa_sound_exit); |
422 | |