xref: /linux/sound/core/sound.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5) 
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  * This function increments the reference counter of the card instance
103  * if an associated instance with the given minor number and type is found.
104  * The caller must call snd_card_unref() appropriately later.
105  */
106 void *snd_lookup_minor_data(unsigned int minor, int type)
107 {
108 	struct snd_minor *mreg;
109 	void *private_data;
110 
111 	if (minor >= ARRAY_SIZE(snd_minors))
112 		return NULL;
113 	mutex_lock(&sound_mutex);
114 	mreg = snd_minors[minor];
115 	if (mreg && mreg->type == type) {
116 		private_data = mreg->private_data;
117 		if (private_data && mreg->card_ptr)
118 			atomic_inc(&mreg->card_ptr->refcount);
119 	} else
120 		private_data = NULL;
121 	mutex_unlock(&sound_mutex);
122 	return private_data;
123 }
124 
125 EXPORT_SYMBOL(snd_lookup_minor_data);
126 
127 #ifdef CONFIG_MODULES
128 static struct snd_minor *autoload_device(unsigned int minor)
129 {
130 	int dev;
131 	mutex_unlock(&sound_mutex); /* release lock temporarily */
132 	dev = SNDRV_MINOR_DEVICE(minor);
133 	if (dev == SNDRV_MINOR_CONTROL) {
134 		/* /dev/aloadC? */
135 		int card = SNDRV_MINOR_CARD(minor);
136 		if (snd_cards[card] == NULL)
137 			snd_request_card(card);
138 	} else if (dev == SNDRV_MINOR_GLOBAL) {
139 		/* /dev/aloadSEQ */
140 		snd_request_other(minor);
141 	}
142 	mutex_lock(&sound_mutex); /* reacuire lock */
143 	return snd_minors[minor];
144 }
145 #else /* !CONFIG_MODULES */
146 #define autoload_device(minor)	NULL
147 #endif /* CONFIG_MODULES */
148 
149 static int snd_open(struct inode *inode, struct file *file)
150 {
151 	unsigned int minor = iminor(inode);
152 	struct snd_minor *mptr = NULL;
153 	const struct file_operations *old_fops;
154 	int err = 0;
155 
156 	if (minor >= ARRAY_SIZE(snd_minors))
157 		return -ENODEV;
158 	mutex_lock(&sound_mutex);
159 	mptr = snd_minors[minor];
160 	if (mptr == NULL) {
161 		mptr = autoload_device(minor);
162 		if (!mptr) {
163 			mutex_unlock(&sound_mutex);
164 			return -ENODEV;
165 		}
166 	}
167 	old_fops = file->f_op;
168 	file->f_op = fops_get(mptr->f_ops);
169 	if (file->f_op == NULL) {
170 		file->f_op = old_fops;
171 		err = -ENODEV;
172 	}
173 	mutex_unlock(&sound_mutex);
174 	if (err < 0)
175 		return err;
176 
177 	if (file->f_op->open) {
178 		err = file->f_op->open(inode, file);
179 		if (err) {
180 			fops_put(file->f_op);
181 			file->f_op = fops_get(old_fops);
182 		}
183 	}
184 	fops_put(old_fops);
185 	return err;
186 }
187 
188 static const struct file_operations snd_fops =
189 {
190 	.owner =	THIS_MODULE,
191 	.open =		snd_open,
192 	.llseek =	noop_llseek,
193 };
194 
195 #ifdef CONFIG_SND_DYNAMIC_MINORS
196 static int snd_find_free_minor(int type)
197 {
198 	int minor;
199 
200 	/* static minors for module auto loading */
201 	if (type == SNDRV_DEVICE_TYPE_SEQUENCER)
202 		return SNDRV_MINOR_SEQUENCER;
203 	if (type == SNDRV_DEVICE_TYPE_TIMER)
204 		return SNDRV_MINOR_TIMER;
205 
206 	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
207 		/* skip static minors still used for module auto loading */
208 		if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL)
209 			continue;
210 		if (minor == SNDRV_MINOR_SEQUENCER ||
211 		    minor == SNDRV_MINOR_TIMER)
212 			continue;
213 		if (!snd_minors[minor])
214 			return minor;
215 	}
216 	return -EBUSY;
217 }
218 #else
219 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
220 {
221 	int minor;
222 
223 	switch (type) {
224 	case SNDRV_DEVICE_TYPE_SEQUENCER:
225 	case SNDRV_DEVICE_TYPE_TIMER:
226 		minor = type;
227 		break;
228 	case SNDRV_DEVICE_TYPE_CONTROL:
229 		if (snd_BUG_ON(!card))
230 			return -EINVAL;
231 		minor = SNDRV_MINOR(card->number, type);
232 		break;
233 	case SNDRV_DEVICE_TYPE_HWDEP:
234 	case SNDRV_DEVICE_TYPE_RAWMIDI:
235 	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
236 	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
237 	case SNDRV_DEVICE_TYPE_COMPRESS:
238 		if (snd_BUG_ON(!card))
239 			return -EINVAL;
240 		minor = SNDRV_MINOR(card->number, type + dev);
241 		break;
242 	default:
243 		return -EINVAL;
244 	}
245 	if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
246 		return -EINVAL;
247 	return minor;
248 }
249 #endif
250 
251 /**
252  * snd_register_device_for_dev - Register the ALSA device file for the card
253  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
254  * @card: the card instance
255  * @dev: the device index
256  * @f_ops: the file operations
257  * @private_data: user pointer for f_ops->open()
258  * @name: the device file name
259  * @device: the &struct device to link this new device to
260  *
261  * Registers an ALSA device file for the given card.
262  * The operators have to be set in reg parameter.
263  *
264  * Returns zero if successful, or a negative error code on failure.
265  */
266 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
267 				const struct file_operations *f_ops,
268 				void *private_data,
269 				const char *name, struct device *device)
270 {
271 	int minor;
272 	struct snd_minor *preg;
273 
274 	if (snd_BUG_ON(!name))
275 		return -EINVAL;
276 	preg = kmalloc(sizeof *preg, GFP_KERNEL);
277 	if (preg == NULL)
278 		return -ENOMEM;
279 	preg->type = type;
280 	preg->card = card ? card->number : -1;
281 	preg->device = dev;
282 	preg->f_ops = f_ops;
283 	preg->private_data = private_data;
284 	preg->card_ptr = card;
285 	mutex_lock(&sound_mutex);
286 #ifdef CONFIG_SND_DYNAMIC_MINORS
287 	minor = snd_find_free_minor(type);
288 #else
289 	minor = snd_kernel_minor(type, card, dev);
290 	if (minor >= 0 && snd_minors[minor])
291 		minor = -EBUSY;
292 #endif
293 	if (minor < 0) {
294 		mutex_unlock(&sound_mutex);
295 		kfree(preg);
296 		return minor;
297 	}
298 	snd_minors[minor] = preg;
299 	preg->dev = device_create(sound_class, device, MKDEV(major, minor),
300 				  private_data, "%s", name);
301 	if (IS_ERR(preg->dev)) {
302 		snd_minors[minor] = NULL;
303 		mutex_unlock(&sound_mutex);
304 		minor = PTR_ERR(preg->dev);
305 		kfree(preg);
306 		return minor;
307 	}
308 
309 	mutex_unlock(&sound_mutex);
310 	return 0;
311 }
312 
313 EXPORT_SYMBOL(snd_register_device_for_dev);
314 
315 /* find the matching minor record
316  * return the index of snd_minor, or -1 if not found
317  */
318 static int find_snd_minor(int type, struct snd_card *card, int dev)
319 {
320 	int cardnum, minor;
321 	struct snd_minor *mptr;
322 
323 	cardnum = card ? card->number : -1;
324 	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
325 		if ((mptr = snd_minors[minor]) != NULL &&
326 		    mptr->type == type &&
327 		    mptr->card == cardnum &&
328 		    mptr->device == dev)
329 			return minor;
330 	return -1;
331 }
332 
333 /**
334  * snd_unregister_device - unregister the device on the given card
335  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
336  * @card: the card instance
337  * @dev: the device index
338  *
339  * Unregisters the device file already registered via
340  * snd_register_device().
341  *
342  * Returns zero if sucecessful, or a negative error code on failure
343  */
344 int snd_unregister_device(int type, struct snd_card *card, int dev)
345 {
346 	int minor;
347 
348 	mutex_lock(&sound_mutex);
349 	minor = find_snd_minor(type, card, dev);
350 	if (minor < 0) {
351 		mutex_unlock(&sound_mutex);
352 		return -EINVAL;
353 	}
354 
355 	device_destroy(sound_class, MKDEV(major, minor));
356 
357 	kfree(snd_minors[minor]);
358 	snd_minors[minor] = NULL;
359 	mutex_unlock(&sound_mutex);
360 	return 0;
361 }
362 
363 EXPORT_SYMBOL(snd_unregister_device);
364 
365 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
366 			      struct device_attribute *attr)
367 {
368 	int minor, ret = -EINVAL;
369 	struct device *d;
370 
371 	mutex_lock(&sound_mutex);
372 	minor = find_snd_minor(type, card, dev);
373 	if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
374 		ret = device_create_file(d, attr);
375 	mutex_unlock(&sound_mutex);
376 	return ret;
377 
378 }
379 
380 EXPORT_SYMBOL(snd_add_device_sysfs_file);
381 
382 #ifdef CONFIG_PROC_FS
383 /*
384  *  INFO PART
385  */
386 
387 static struct snd_info_entry *snd_minor_info_entry;
388 
389 static const char *snd_device_type_name(int type)
390 {
391 	switch (type) {
392 	case SNDRV_DEVICE_TYPE_CONTROL:
393 		return "control";
394 	case SNDRV_DEVICE_TYPE_HWDEP:
395 		return "hardware dependent";
396 	case SNDRV_DEVICE_TYPE_RAWMIDI:
397 		return "raw midi";
398 	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
399 		return "digital audio playback";
400 	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
401 		return "digital audio capture";
402 	case SNDRV_DEVICE_TYPE_SEQUENCER:
403 		return "sequencer";
404 	case SNDRV_DEVICE_TYPE_TIMER:
405 		return "timer";
406 	default:
407 		return "?";
408 	}
409 }
410 
411 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
412 {
413 	int minor;
414 	struct snd_minor *mptr;
415 
416 	mutex_lock(&sound_mutex);
417 	for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
418 		if (!(mptr = snd_minors[minor]))
419 			continue;
420 		if (mptr->card >= 0) {
421 			if (mptr->device >= 0)
422 				snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
423 					    minor, mptr->card, mptr->device,
424 					    snd_device_type_name(mptr->type));
425 			else
426 				snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
427 					    minor, mptr->card,
428 					    snd_device_type_name(mptr->type));
429 		} else
430 			snd_iprintf(buffer, "%3i:        : %s\n", minor,
431 				    snd_device_type_name(mptr->type));
432 	}
433 	mutex_unlock(&sound_mutex);
434 }
435 
436 int __init snd_minor_info_init(void)
437 {
438 	struct snd_info_entry *entry;
439 
440 	entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
441 	if (entry) {
442 		entry->c.text.read = snd_minor_info_read;
443 		if (snd_info_register(entry) < 0) {
444 			snd_info_free_entry(entry);
445 			entry = NULL;
446 		}
447 	}
448 	snd_minor_info_entry = entry;
449 	return 0;
450 }
451 
452 int __exit snd_minor_info_done(void)
453 {
454 	snd_info_free_entry(snd_minor_info_entry);
455 	return 0;
456 }
457 #endif /* CONFIG_PROC_FS */
458 
459 /*
460  *  INIT PART
461  */
462 
463 static int __init alsa_sound_init(void)
464 {
465 	snd_major = major;
466 	snd_ecards_limit = cards_limit;
467 	if (register_chrdev(major, "alsa", &snd_fops)) {
468 		snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
469 		return -EIO;
470 	}
471 	if (snd_info_init() < 0) {
472 		unregister_chrdev(major, "alsa");
473 		return -ENOMEM;
474 	}
475 	snd_info_minor_register();
476 #ifndef MODULE
477 	printk(KERN_INFO "Advanced Linux Sound Architecture Driver Initialized.\n");
478 #endif
479 	return 0;
480 }
481 
482 static void __exit alsa_sound_exit(void)
483 {
484 	snd_info_minor_unregister();
485 	snd_info_done();
486 	unregister_chrdev(major, "alsa");
487 }
488 
489 subsys_initcall(alsa_sound_init);
490 module_exit(alsa_sound_exit);
491