xref: /linux/sound/core/sound.c (revision f49f4ab95c301dbccad0efe85296d908b8ae7ad4) 
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/control.h>
31 #include <sound/initval.h>
32 #include <linux/kmod.h>
33 #include <linux/mutex.h>
34 
35 static int major = CONFIG_SND_MAJOR;
36 int snd_major;
37 EXPORT_SYMBOL(snd_major);
38 
39 static int cards_limit = 1;
40 
41 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
42 MODULE_DESCRIPTION("Advanced Linux Sound Architecture driver for soundcards.");
43 MODULE_LICENSE("GPL");
44 module_param(major, int, 0444);
45 MODULE_PARM_DESC(major, "Major # for sound driver.");
46 module_param(cards_limit, int, 0444);
47 MODULE_PARM_DESC(cards_limit, "Count of auto-loadable soundcards.");
48 MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR);
49 
50 /* this one holds the actual max. card number currently available.
51  * as default, it's identical with cards_limit option.  when more
52  * modules are loaded manually, this limit number increases, too.
53  */
54 int snd_ecards_limit;
55 EXPORT_SYMBOL(snd_ecards_limit);
56 
57 static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
58 static DEFINE_MUTEX(sound_mutex);
59 
60 #ifdef CONFIG_MODULES
61 
62 /**
63  * snd_request_card - try to load the card module
64  * @card: the card number
65  *
66  * Tries to load the module "snd-card-X" for the given card number
67  * via request_module.  Returns immediately if already loaded.
68  */
69 void snd_request_card(int card)
70 {
71 	if (snd_card_locked(card))
72 		return;
73 	if (card < 0 || card >= cards_limit)
74 		return;
75 	request_module("snd-card-%i", card);
76 }
77 
78 EXPORT_SYMBOL(snd_request_card);
79 
80 static void snd_request_other(int minor)
81 {
82 	char *str;
83 
84 	switch (minor) {
85 	case SNDRV_MINOR_SEQUENCER:	str = "snd-seq";	break;
86 	case SNDRV_MINOR_TIMER:		str = "snd-timer";	break;
87 	default:			return;
88 	}
89 	request_module(str);
90 }
91 
92 #endif	/* modular kernel */
93 
94 /**
95  * snd_lookup_minor_data - get user data of a registered device
96  * @minor: the minor number
97  * @type: device type (SNDRV_DEVICE_TYPE_XXX)
98  *
99  * Checks that a minor device with the specified type is registered, and returns
100  * its user data pointer.
101  */
102 void *snd_lookup_minor_data(unsigned int minor, int type)
103 {
104 	struct snd_minor *mreg;
105 	void *private_data;
106 
107 	if (minor >= ARRAY_SIZE(snd_minors))
108 		return NULL;
109 	mutex_lock(&sound_mutex);
110 	mreg = snd_minors[minor];
111 	if (mreg && mreg->type == type)
112 		private_data = mreg->private_data;
113 	else
114 		private_data = NULL;
115 	mutex_unlock(&sound_mutex);
116 	return private_data;
117 }
118 
119 EXPORT_SYMBOL(snd_lookup_minor_data);
120 
121 #ifdef CONFIG_MODULES
122 static struct snd_minor *autoload_device(unsigned int minor)
123 {
124 	int dev;
125 	mutex_unlock(&sound_mutex); /* release lock temporarily */
126 	dev = SNDRV_MINOR_DEVICE(minor);
127 	if (dev == SNDRV_MINOR_CONTROL) {
128 		/* /dev/aloadC? */
129 		int card = SNDRV_MINOR_CARD(minor);
130 		if (snd_cards[card] == NULL)
131 			snd_request_card(card);
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 *old_fops;
148 	int err = 0;
149 
150 	if (minor >= ARRAY_SIZE(snd_minors))
151 		return -ENODEV;
152 	mutex_lock(&sound_mutex);
153 	mptr = snd_minors[minor];
154 	if (mptr == NULL) {
155 		mptr = autoload_device(minor);
156 		if (!mptr) {
157 			mutex_unlock(&sound_mutex);
158 			return -ENODEV;
159 		}
160 	}
161 	old_fops = file->f_op;
162 	file->f_op = fops_get(mptr->f_ops);
163 	if (file->f_op == NULL) {
164 		file->f_op = old_fops;
165 		err = -ENODEV;
166 	}
167 	mutex_unlock(&sound_mutex);
168 	if (err < 0)
169 		return err;
170 
171 	if (file->f_op->open) {
172 		err = file->f_op->open(inode, file);
173 		if (err) {
174 			fops_put(file->f_op);
175 			file->f_op = fops_get(old_fops);
176 		}
177 	}
178 	fops_put(old_fops);
179 	return err;
180 }
181 
182 static const struct file_operations snd_fops =
183 {
184 	.owner =	THIS_MODULE,
185 	.open =		snd_open,
186 	.llseek =	noop_llseek,
187 };
188 
189 #ifdef CONFIG_SND_DYNAMIC_MINORS
190 static int snd_find_free_minor(int type)
191 {
192 	int minor;
193 
194 	/* static minors for module auto loading */
195 	if (type == SNDRV_DEVICE_TYPE_SEQUENCER)
196 		return SNDRV_MINOR_SEQUENCER;
197 	if (type == SNDRV_DEVICE_TYPE_TIMER)
198 		return SNDRV_MINOR_TIMER;
199 
200 	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
201 		/* skip static minors still used for module auto loading */
202 		if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL)
203 			continue;
204 		if (minor == SNDRV_MINOR_SEQUENCER ||
205 		    minor == SNDRV_MINOR_TIMER)
206 			continue;
207 		if (!snd_minors[minor])
208 			return minor;
209 	}
210 	return -EBUSY;
211 }
212 #else
213 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
214 {
215 	int minor;
216 
217 	switch (type) {
218 	case SNDRV_DEVICE_TYPE_SEQUENCER:
219 	case SNDRV_DEVICE_TYPE_TIMER:
220 		minor = type;
221 		break;
222 	case SNDRV_DEVICE_TYPE_CONTROL:
223 		if (snd_BUG_ON(!card))
224 			return -EINVAL;
225 		minor = SNDRV_MINOR(card->number, type);
226 		break;
227 	case SNDRV_DEVICE_TYPE_HWDEP:
228 	case SNDRV_DEVICE_TYPE_RAWMIDI:
229 	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
230 	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
231 	case SNDRV_DEVICE_TYPE_COMPRESS:
232 		if (snd_BUG_ON(!card))
233 			return -EINVAL;
234 		minor = SNDRV_MINOR(card->number, type + dev);
235 		break;
236 	default:
237 		return -EINVAL;
238 	}
239 	if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
240 		return -EINVAL;
241 	return minor;
242 }
243 #endif
244 
245 /**
246  * snd_register_device_for_dev - Register the ALSA device file for the card
247  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
248  * @card: the card instance
249  * @dev: the device index
250  * @f_ops: the file operations
251  * @private_data: user pointer for f_ops->open()
252  * @name: the device file name
253  * @device: the &struct device to link this new device to
254  *
255  * Registers an ALSA device file for the given card.
256  * The operators have to be set in reg parameter.
257  *
258  * Returns zero if successful, or a negative error code on failure.
259  */
260 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
261 				const struct file_operations *f_ops,
262 				void *private_data,
263 				const char *name, struct device *device)
264 {
265 	int minor;
266 	struct snd_minor *preg;
267 
268 	if (snd_BUG_ON(!name))
269 		return -EINVAL;
270 	preg = kmalloc(sizeof *preg, GFP_KERNEL);
271 	if (preg == NULL)
272 		return -ENOMEM;
273 	preg->type = type;
274 	preg->card = card ? card->number : -1;
275 	preg->device = dev;
276 	preg->f_ops = f_ops;
277 	preg->private_data = private_data;
278 	mutex_lock(&sound_mutex);
279 #ifdef CONFIG_SND_DYNAMIC_MINORS
280 	minor = snd_find_free_minor(type);
281 #else
282 	minor = snd_kernel_minor(type, card, dev);
283 	if (minor >= 0 && snd_minors[minor])
284 		minor = -EBUSY;
285 #endif
286 	if (minor < 0) {
287 		mutex_unlock(&sound_mutex);
288 		kfree(preg);
289 		return minor;
290 	}
291 	snd_minors[minor] = preg;
292 	preg->dev = device_create(sound_class, device, MKDEV(major, minor),
293 				  private_data, "%s", name);
294 	if (IS_ERR(preg->dev)) {
295 		snd_minors[minor] = NULL;
296 		mutex_unlock(&sound_mutex);
297 		minor = PTR_ERR(preg->dev);
298 		kfree(preg);
299 		return minor;
300 	}
301 
302 	mutex_unlock(&sound_mutex);
303 	return 0;
304 }
305 
306 EXPORT_SYMBOL(snd_register_device_for_dev);
307 
308 /* find the matching minor record
309  * return the index of snd_minor, or -1 if not found
310  */
311 static int find_snd_minor(int type, struct snd_card *card, int dev)
312 {
313 	int cardnum, minor;
314 	struct snd_minor *mptr;
315 
316 	cardnum = card ? card->number : -1;
317 	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
318 		if ((mptr = snd_minors[minor]) != NULL &&
319 		    mptr->type == type &&
320 		    mptr->card == cardnum &&
321 		    mptr->device == dev)
322 			return minor;
323 	return -1;
324 }
325 
326 /**
327  * snd_unregister_device - unregister the device on the given card
328  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
329  * @card: the card instance
330  * @dev: the device index
331  *
332  * Unregisters the device file already registered via
333  * snd_register_device().
334  *
335  * Returns zero if sucecessful, or a negative error code on failure
336  */
337 int snd_unregister_device(int type, struct snd_card *card, int dev)
338 {
339 	int minor;
340 
341 	mutex_lock(&sound_mutex);
342 	minor = find_snd_minor(type, card, dev);
343 	if (minor < 0) {
344 		mutex_unlock(&sound_mutex);
345 		return -EINVAL;
346 	}
347 
348 	device_destroy(sound_class, MKDEV(major, minor));
349 
350 	kfree(snd_minors[minor]);
351 	snd_minors[minor] = NULL;
352 	mutex_unlock(&sound_mutex);
353 	return 0;
354 }
355 
356 EXPORT_SYMBOL(snd_unregister_device);
357 
358 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
359 			      struct device_attribute *attr)
360 {
361 	int minor, ret = -EINVAL;
362 	struct device *d;
363 
364 	mutex_lock(&sound_mutex);
365 	minor = find_snd_minor(type, card, dev);
366 	if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
367 		ret = device_create_file(d, attr);
368 	mutex_unlock(&sound_mutex);
369 	return ret;
370 
371 }
372 
373 EXPORT_SYMBOL(snd_add_device_sysfs_file);
374 
375 #ifdef CONFIG_PROC_FS
376 /*
377  *  INFO PART
378  */
379 
380 static struct snd_info_entry *snd_minor_info_entry;
381 
382 static const char *snd_device_type_name(int type)
383 {
384 	switch (type) {
385 	case SNDRV_DEVICE_TYPE_CONTROL:
386 		return "control";
387 	case SNDRV_DEVICE_TYPE_HWDEP:
388 		return "hardware dependent";
389 	case SNDRV_DEVICE_TYPE_RAWMIDI:
390 		return "raw midi";
391 	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
392 		return "digital audio playback";
393 	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
394 		return "digital audio capture";
395 	case SNDRV_DEVICE_TYPE_SEQUENCER:
396 		return "sequencer";
397 	case SNDRV_DEVICE_TYPE_TIMER:
398 		return "timer";
399 	default:
400 		return "?";
401 	}
402 }
403 
404 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
405 {
406 	int minor;
407 	struct snd_minor *mptr;
408 
409 	mutex_lock(&sound_mutex);
410 	for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
411 		if (!(mptr = snd_minors[minor]))
412 			continue;
413 		if (mptr->card >= 0) {
414 			if (mptr->device >= 0)
415 				snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
416 					    minor, mptr->card, mptr->device,
417 					    snd_device_type_name(mptr->type));
418 			else
419 				snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
420 					    minor, mptr->card,
421 					    snd_device_type_name(mptr->type));
422 		} else
423 			snd_iprintf(buffer, "%3i:        : %s\n", minor,
424 				    snd_device_type_name(mptr->type));
425 	}
426 	mutex_unlock(&sound_mutex);
427 }
428 
429 int __init snd_minor_info_init(void)
430 {
431 	struct snd_info_entry *entry;
432 
433 	entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
434 	if (entry) {
435 		entry->c.text.read = snd_minor_info_read;
436 		if (snd_info_register(entry) < 0) {
437 			snd_info_free_entry(entry);
438 			entry = NULL;
439 		}
440 	}
441 	snd_minor_info_entry = entry;
442 	return 0;
443 }
444 
445 int __exit snd_minor_info_done(void)
446 {
447 	snd_info_free_entry(snd_minor_info_entry);
448 	return 0;
449 }
450 #endif /* CONFIG_PROC_FS */
451 
452 /*
453  *  INIT PART
454  */
455 
456 static int __init alsa_sound_init(void)
457 {
458 	snd_major = major;
459 	snd_ecards_limit = cards_limit;
460 	if (register_chrdev(major, "alsa", &snd_fops)) {
461 		snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
462 		return -EIO;
463 	}
464 	if (snd_info_init() < 0) {
465 		unregister_chrdev(major, "alsa");
466 		return -ENOMEM;
467 	}
468 	snd_info_minor_register();
469 #ifndef MODULE
470 	printk(KERN_INFO "Advanced Linux Sound Architecture Driver Initialized.\n");
471 #endif
472 	return 0;
473 }
474 
475 static void __exit alsa_sound_exit(void)
476 {
477 	snd_info_minor_unregister();
478 	snd_info_done();
479 	unregister_chrdev(major, "alsa");
480 }
481 
482 subsys_initcall(alsa_sound_init);
483 module_exit(alsa_sound_exit);
484