xref: /openbmc/linux/sound/core/sound.c (revision 95e9fd10) 
1 /*
2  *  Advanced Linux Sound Architecture
3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4  *
5  *
6  *   This program is free software; you can redistribute it and/or modify
7  *   it under the terms of the GNU General Public License as published by
8  *   the Free Software Foundation; either version 2 of the License, or
9  *   (at your option) any later version.
10  *
11  *   This program is distributed in the hope that it will be useful,
12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *   GNU General Public License for more details.
15  *
16  *   You should have received a copy of the GNU General Public License
17  *   along with this program; if not, write to the Free Software
18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19  *
20  */
21 
22 #include <linux/init.h>
23 #include <linux/slab.h>
24 #include <linux/time.h>
25 #include <linux/device.h>
26 #include <linux/module.h>
27 #include <sound/core.h>
28 #include <sound/minors.h>
29 #include <sound/info.h>
30 #include <sound/version.h>
31 #include <sound/control.h>
32 #include <sound/initval.h>
33 #include <linux/kmod.h>
34 #include <linux/mutex.h>
35 
36 static int major = CONFIG_SND_MAJOR;
37 int snd_major;
38 EXPORT_SYMBOL(snd_major);
39 
40 static int cards_limit = 1;
41 
42 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
43 MODULE_DESCRIPTION("Advanced Linux Sound Architecture driver for soundcards.");
44 MODULE_LICENSE("GPL");
45 module_param(major, int, 0444);
46 MODULE_PARM_DESC(major, "Major # for sound driver.");
47 module_param(cards_limit, int, 0444);
48 MODULE_PARM_DESC(cards_limit, "Count of auto-loadable soundcards.");
49 MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR);
50 
51 /* this one holds the actual max. card number currently available.
52  * as default, it's identical with cards_limit option.  when more
53  * modules are loaded manually, this limit number increases, too.
54  */
55 int snd_ecards_limit;
56 EXPORT_SYMBOL(snd_ecards_limit);
57 
58 static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
59 static DEFINE_MUTEX(sound_mutex);
60 
61 #ifdef CONFIG_MODULES
62 
63 /**
64  * snd_request_card - try to load the card module
65  * @card: the card number
66  *
67  * Tries to load the module "snd-card-X" for the given card number
68  * via request_module.  Returns immediately if already loaded.
69  */
70 void snd_request_card(int card)
71 {
72 	if (snd_card_locked(card))
73 		return;
74 	if (card < 0 || card >= cards_limit)
75 		return;
76 	request_module("snd-card-%i", card);
77 }
78 
79 EXPORT_SYMBOL(snd_request_card);
80 
81 static void snd_request_other(int minor)
82 {
83 	char *str;
84 
85 	switch (minor) {
86 	case SNDRV_MINOR_SEQUENCER:	str = "snd-seq";	break;
87 	case SNDRV_MINOR_TIMER:		str = "snd-timer";	break;
88 	default:			return;
89 	}
90 	request_module(str);
91 }
92 
93 #endif	/* modular kernel */
94 
95 /**
96  * snd_lookup_minor_data - get user data of a registered device
97  * @minor: the minor number
98  * @type: device type (SNDRV_DEVICE_TYPE_XXX)
99  *
100  * Checks that a minor device with the specified type is registered, and returns
101  * its user data pointer.
102  */
103 void *snd_lookup_minor_data(unsigned int minor, int type)
104 {
105 	struct snd_minor *mreg;
106 	void *private_data;
107 
108 	if (minor >= ARRAY_SIZE(snd_minors))
109 		return NULL;
110 	mutex_lock(&sound_mutex);
111 	mreg = snd_minors[minor];
112 	if (mreg && mreg->type == type)
113 		private_data = mreg->private_data;
114 	else
115 		private_data = NULL;
116 	mutex_unlock(&sound_mutex);
117 	return private_data;
118 }
119 
120 EXPORT_SYMBOL(snd_lookup_minor_data);
121 
122 #ifdef CONFIG_MODULES
123 static struct snd_minor *autoload_device(unsigned int minor)
124 {
125 	int dev;
126 	mutex_unlock(&sound_mutex); /* release lock temporarily */
127 	dev = SNDRV_MINOR_DEVICE(minor);
128 	if (dev == SNDRV_MINOR_CONTROL) {
129 		/* /dev/aloadC? */
130 		int card = SNDRV_MINOR_CARD(minor);
131 		if (snd_cards[card] == NULL)
132 			snd_request_card(card);
133 	} else if (dev == SNDRV_MINOR_GLOBAL) {
134 		/* /dev/aloadSEQ */
135 		snd_request_other(minor);
136 	}
137 	mutex_lock(&sound_mutex); /* reacuire lock */
138 	return snd_minors[minor];
139 }
140 #else /* !CONFIG_MODULES */
141 #define autoload_device(minor)	NULL
142 #endif /* CONFIG_MODULES */
143 
144 static int snd_open(struct inode *inode, struct file *file)
145 {
146 	unsigned int minor = iminor(inode);
147 	struct snd_minor *mptr = NULL;
148 	const struct file_operations *old_fops;
149 	int err = 0;
150 
151 	if (minor >= ARRAY_SIZE(snd_minors))
152 		return -ENODEV;
153 	mutex_lock(&sound_mutex);
154 	mptr = snd_minors[minor];
155 	if (mptr == NULL) {
156 		mptr = autoload_device(minor);
157 		if (!mptr) {
158 			mutex_unlock(&sound_mutex);
159 			return -ENODEV;
160 		}
161 	}
162 	old_fops = file->f_op;
163 	file->f_op = fops_get(mptr->f_ops);
164 	if (file->f_op == NULL) {
165 		file->f_op = old_fops;
166 		err = -ENODEV;
167 	}
168 	mutex_unlock(&sound_mutex);
169 	if (err < 0)
170 		return err;
171 
172 	if (file->f_op->open) {
173 		err = file->f_op->open(inode, file);
174 		if (err) {
175 			fops_put(file->f_op);
176 			file->f_op = fops_get(old_fops);
177 		}
178 	}
179 	fops_put(old_fops);
180 	return err;
181 }
182 
183 static const struct file_operations snd_fops =
184 {
185 	.owner =	THIS_MODULE,
186 	.open =		snd_open,
187 	.llseek =	noop_llseek,
188 };
189 
190 #ifdef CONFIG_SND_DYNAMIC_MINORS
191 static int snd_find_free_minor(int type)
192 {
193 	int minor;
194 
195 	/* static minors for module auto loading */
196 	if (type == SNDRV_DEVICE_TYPE_SEQUENCER)
197 		return SNDRV_MINOR_SEQUENCER;
198 	if (type == SNDRV_DEVICE_TYPE_TIMER)
199 		return SNDRV_MINOR_TIMER;
200 
201 	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
202 		/* skip static minors still used for module auto loading */
203 		if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL)
204 			continue;
205 		if (minor == SNDRV_MINOR_SEQUENCER ||
206 		    minor == SNDRV_MINOR_TIMER)
207 			continue;
208 		if (!snd_minors[minor])
209 			return minor;
210 	}
211 	return -EBUSY;
212 }
213 #else
214 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
215 {
216 	int minor;
217 
218 	switch (type) {
219 	case SNDRV_DEVICE_TYPE_SEQUENCER:
220 	case SNDRV_DEVICE_TYPE_TIMER:
221 		minor = type;
222 		break;
223 	case SNDRV_DEVICE_TYPE_CONTROL:
224 		if (snd_BUG_ON(!card))
225 			return -EINVAL;
226 		minor = SNDRV_MINOR(card->number, type);
227 		break;
228 	case SNDRV_DEVICE_TYPE_HWDEP:
229 	case SNDRV_DEVICE_TYPE_RAWMIDI:
230 	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
231 	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
232 	case SNDRV_DEVICE_TYPE_COMPRESS:
233 		if (snd_BUG_ON(!card))
234 			return -EINVAL;
235 		minor = SNDRV_MINOR(card->number, type + dev);
236 		break;
237 	default:
238 		return -EINVAL;
239 	}
240 	if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
241 		return -EINVAL;
242 	return minor;
243 }
244 #endif
245 
246 /**
247  * snd_register_device_for_dev - Register the ALSA device file for the card
248  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
249  * @card: the card instance
250  * @dev: the device index
251  * @f_ops: the file operations
252  * @private_data: user pointer for f_ops->open()
253  * @name: the device file name
254  * @device: the &struct device to link this new device to
255  *
256  * Registers an ALSA device file for the given card.
257  * The operators have to be set in reg parameter.
258  *
259  * Returns zero if successful, or a negative error code on failure.
260  */
261 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
262 				const struct file_operations *f_ops,
263 				void *private_data,
264 				const char *name, struct device *device)
265 {
266 	int minor;
267 	struct snd_minor *preg;
268 
269 	if (snd_BUG_ON(!name))
270 		return -EINVAL;
271 	preg = kmalloc(sizeof *preg, GFP_KERNEL);
272 	if (preg == NULL)
273 		return -ENOMEM;
274 	preg->type = type;
275 	preg->card = card ? card->number : -1;
276 	preg->device = dev;
277 	preg->f_ops = f_ops;
278 	preg->private_data = private_data;
279 	mutex_lock(&sound_mutex);
280 #ifdef CONFIG_SND_DYNAMIC_MINORS
281 	minor = snd_find_free_minor(type);
282 #else
283 	minor = snd_kernel_minor(type, card, dev);
284 	if (minor >= 0 && snd_minors[minor])
285 		minor = -EBUSY;
286 #endif
287 	if (minor < 0) {
288 		mutex_unlock(&sound_mutex);
289 		kfree(preg);
290 		return minor;
291 	}
292 	snd_minors[minor] = preg;
293 	preg->dev = device_create(sound_class, device, MKDEV(major, minor),
294 				  private_data, "%s", name);
295 	if (IS_ERR(preg->dev)) {
296 		snd_minors[minor] = NULL;
297 		mutex_unlock(&sound_mutex);
298 		minor = PTR_ERR(preg->dev);
299 		kfree(preg);
300 		return minor;
301 	}
302 
303 	mutex_unlock(&sound_mutex);
304 	return 0;
305 }
306 
307 EXPORT_SYMBOL(snd_register_device_for_dev);
308 
309 /* find the matching minor record
310  * return the index of snd_minor, or -1 if not found
311  */
312 static int find_snd_minor(int type, struct snd_card *card, int dev)
313 {
314 	int cardnum, minor;
315 	struct snd_minor *mptr;
316 
317 	cardnum = card ? card->number : -1;
318 	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
319 		if ((mptr = snd_minors[minor]) != NULL &&
320 		    mptr->type == type &&
321 		    mptr->card == cardnum &&
322 		    mptr->device == dev)
323 			return minor;
324 	return -1;
325 }
326 
327 /**
328  * snd_unregister_device - unregister the device on the given card
329  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
330  * @card: the card instance
331  * @dev: the device index
332  *
333  * Unregisters the device file already registered via
334  * snd_register_device().
335  *
336  * Returns zero if sucecessful, or a negative error code on failure
337  */
338 int snd_unregister_device(int type, struct snd_card *card, int dev)
339 {
340 	int minor;
341 
342 	mutex_lock(&sound_mutex);
343 	minor = find_snd_minor(type, card, dev);
344 	if (minor < 0) {
345 		mutex_unlock(&sound_mutex);
346 		return -EINVAL;
347 	}
348 
349 	device_destroy(sound_class, MKDEV(major, minor));
350 
351 	kfree(snd_minors[minor]);
352 	snd_minors[minor] = NULL;
353 	mutex_unlock(&sound_mutex);
354 	return 0;
355 }
356 
357 EXPORT_SYMBOL(snd_unregister_device);
358 
359 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
360 			      struct device_attribute *attr)
361 {
362 	int minor, ret = -EINVAL;
363 	struct device *d;
364 
365 	mutex_lock(&sound_mutex);
366 	minor = find_snd_minor(type, card, dev);
367 	if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
368 		ret = device_create_file(d, attr);
369 	mutex_unlock(&sound_mutex);
370 	return ret;
371 
372 }
373 
374 EXPORT_SYMBOL(snd_add_device_sysfs_file);
375 
376 #ifdef CONFIG_PROC_FS
377 /*
378  *  INFO PART
379  */
380 
381 static struct snd_info_entry *snd_minor_info_entry;
382 
383 static const char *snd_device_type_name(int type)
384 {
385 	switch (type) {
386 	case SNDRV_DEVICE_TYPE_CONTROL:
387 		return "control";
388 	case SNDRV_DEVICE_TYPE_HWDEP:
389 		return "hardware dependent";
390 	case SNDRV_DEVICE_TYPE_RAWMIDI:
391 		return "raw midi";
392 	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
393 		return "digital audio playback";
394 	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
395 		return "digital audio capture";
396 	case SNDRV_DEVICE_TYPE_SEQUENCER:
397 		return "sequencer";
398 	case SNDRV_DEVICE_TYPE_TIMER:
399 		return "timer";
400 	default:
401 		return "?";
402 	}
403 }
404 
405 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
406 {
407 	int minor;
408 	struct snd_minor *mptr;
409 
410 	mutex_lock(&sound_mutex);
411 	for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
412 		if (!(mptr = snd_minors[minor]))
413 			continue;
414 		if (mptr->card >= 0) {
415 			if (mptr->device >= 0)
416 				snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
417 					    minor, mptr->card, mptr->device,
418 					    snd_device_type_name(mptr->type));
419 			else
420 				snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
421 					    minor, mptr->card,
422 					    snd_device_type_name(mptr->type));
423 		} else
424 			snd_iprintf(buffer, "%3i:        : %s\n", minor,
425 				    snd_device_type_name(mptr->type));
426 	}
427 	mutex_unlock(&sound_mutex);
428 }
429 
430 int __init snd_minor_info_init(void)
431 {
432 	struct snd_info_entry *entry;
433 
434 	entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
435 	if (entry) {
436 		entry->c.text.read = snd_minor_info_read;
437 		if (snd_info_register(entry) < 0) {
438 			snd_info_free_entry(entry);
439 			entry = NULL;
440 		}
441 	}
442 	snd_minor_info_entry = entry;
443 	return 0;
444 }
445 
446 int __exit snd_minor_info_done(void)
447 {
448 	snd_info_free_entry(snd_minor_info_entry);
449 	return 0;
450 }
451 #endif /* CONFIG_PROC_FS */
452 
453 /*
454  *  INIT PART
455  */
456 
457 static int __init alsa_sound_init(void)
458 {
459 	snd_major = major;
460 	snd_ecards_limit = cards_limit;
461 	if (register_chrdev(major, "alsa", &snd_fops)) {
462 		snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
463 		return -EIO;
464 	}
465 	if (snd_info_init() < 0) {
466 		unregister_chrdev(major, "alsa");
467 		return -ENOMEM;
468 	}
469 	snd_info_minor_register();
470 #ifndef MODULE
471 	printk(KERN_INFO "Advanced Linux Sound Architecture Driver Version " CONFIG_SND_VERSION CONFIG_SND_DATE ".\n");
472 #endif
473 	return 0;
474 }
475 
476 static void __exit alsa_sound_exit(void)
477 {
478 	snd_info_minor_unregister();
479 	snd_info_done();
480 	unregister_chrdev(major, "alsa");
481 }
482 
483 subsys_initcall(alsa_sound_init);
484 module_exit(alsa_sound_exit);
485