xref: /openbmc/linux/sound/core/sound.c (revision 1fa6ac37) 
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/smp_lock.h>
25 #include <linux/time.h>
26 #include <linux/device.h>
27 #include <linux/moduleparam.h>
28 #include <sound/core.h>
29 #include <sound/minors.h>
30 #include <sound/info.h>
31 #include <sound/version.h>
32 #include <sound/control.h>
33 #include <sound/initval.h>
34 #include <linux/kmod.h>
35 #include <linux/mutex.h>
36 
37 static int major = CONFIG_SND_MAJOR;
38 int snd_major;
39 EXPORT_SYMBOL(snd_major);
40 
41 static int cards_limit = 1;
42 
43 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
44 MODULE_DESCRIPTION("Advanced Linux Sound Architecture driver for soundcards.");
45 MODULE_LICENSE("GPL");
46 module_param(major, int, 0444);
47 MODULE_PARM_DESC(major, "Major # for sound driver.");
48 module_param(cards_limit, int, 0444);
49 MODULE_PARM_DESC(cards_limit, "Count of auto-loadable soundcards.");
50 MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR);
51 
52 /* this one holds the actual max. card number currently available.
53  * as default, it's identical with cards_limit option.  when more
54  * modules are loaded manually, this limit number increases, too.
55  */
56 int snd_ecards_limit;
57 EXPORT_SYMBOL(snd_ecards_limit);
58 
59 static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
60 static DEFINE_MUTEX(sound_mutex);
61 
62 #ifdef CONFIG_MODULES
63 
64 /**
65  * snd_request_card - try to load the card module
66  * @card: the card number
67  *
68  * Tries to load the module "snd-card-X" for the given card number
69  * via request_module.  Returns immediately if already loaded.
70  */
71 void snd_request_card(int card)
72 {
73 	if (snd_card_locked(card))
74 		return;
75 	if (card < 0 || card >= cards_limit)
76 		return;
77 	request_module("snd-card-%i", card);
78 }
79 
80 EXPORT_SYMBOL(snd_request_card);
81 
82 static void snd_request_other(int minor)
83 {
84 	char *str;
85 
86 	switch (minor) {
87 	case SNDRV_MINOR_SEQUENCER:	str = "snd-seq";	break;
88 	case SNDRV_MINOR_TIMER:		str = "snd-timer";	break;
89 	default:			return;
90 	}
91 	request_module(str);
92 }
93 
94 #endif	/* modular kernel */
95 
96 /**
97  * snd_lookup_minor_data - get user data of a registered device
98  * @minor: the minor number
99  * @type: device type (SNDRV_DEVICE_TYPE_XXX)
100  *
101  * Checks that a minor device with the specified type is registered, and returns
102  * its user data pointer.
103  */
104 void *snd_lookup_minor_data(unsigned int minor, int type)
105 {
106 	struct snd_minor *mreg;
107 	void *private_data;
108 
109 	if (minor >= ARRAY_SIZE(snd_minors))
110 		return NULL;
111 	mutex_lock(&sound_mutex);
112 	mreg = snd_minors[minor];
113 	if (mreg && mreg->type == type)
114 		private_data = mreg->private_data;
115 	else
116 		private_data = NULL;
117 	mutex_unlock(&sound_mutex);
118 	return private_data;
119 }
120 
121 EXPORT_SYMBOL(snd_lookup_minor_data);
122 
123 #ifdef CONFIG_MODULES
124 static struct snd_minor *autoload_device(unsigned int minor)
125 {
126 	int dev;
127 	mutex_unlock(&sound_mutex); /* release lock temporarily */
128 	dev = SNDRV_MINOR_DEVICE(minor);
129 	if (dev == SNDRV_MINOR_CONTROL) {
130 		/* /dev/aloadC? */
131 		int card = SNDRV_MINOR_CARD(minor);
132 		if (snd_cards[card] == NULL)
133 			snd_request_card(card);
134 	} else if (dev == SNDRV_MINOR_GLOBAL) {
135 		/* /dev/aloadSEQ */
136 		snd_request_other(minor);
137 	}
138 	mutex_lock(&sound_mutex); /* reacuire lock */
139 	return snd_minors[minor];
140 }
141 #else /* !CONFIG_MODULES */
142 #define autoload_device(minor)	NULL
143 #endif /* CONFIG_MODULES */
144 
145 static int snd_open(struct inode *inode, struct file *file)
146 {
147 	unsigned int minor = iminor(inode);
148 	struct snd_minor *mptr = NULL;
149 	const struct file_operations *old_fops;
150 	int err = 0;
151 
152 	if (minor >= ARRAY_SIZE(snd_minors))
153 		return -ENODEV;
154 	mutex_lock(&sound_mutex);
155 	mptr = snd_minors[minor];
156 	if (mptr == NULL) {
157 		mptr = autoload_device(minor);
158 		if (!mptr) {
159 			mutex_unlock(&sound_mutex);
160 			return -ENODEV;
161 		}
162 	}
163 	old_fops = file->f_op;
164 	file->f_op = fops_get(mptr->f_ops);
165 	if (file->f_op == NULL) {
166 		file->f_op = old_fops;
167 		err = -ENODEV;
168 	}
169 	mutex_unlock(&sound_mutex);
170 	if (err < 0)
171 		return err;
172 
173 	if (file->f_op->open) {
174 		err = file->f_op->open(inode, file);
175 		if (err) {
176 			fops_put(file->f_op);
177 			file->f_op = fops_get(old_fops);
178 		}
179 	}
180 	fops_put(old_fops);
181 	return err;
182 }
183 
184 static const struct file_operations snd_fops =
185 {
186 	.owner =	THIS_MODULE,
187 	.open =		snd_open
188 };
189 
190 #ifdef CONFIG_SND_DYNAMIC_MINORS
191 static int snd_find_free_minor(void)
192 {
193 	int minor;
194 
195 	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
196 		/* skip minors still used statically for autoloading devices */
197 		if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL ||
198 		    minor == SNDRV_MINOR_SEQUENCER)
199 			continue;
200 		if (!snd_minors[minor])
201 			return minor;
202 	}
203 	return -EBUSY;
204 }
205 #else
206 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
207 {
208 	int minor;
209 
210 	switch (type) {
211 	case SNDRV_DEVICE_TYPE_SEQUENCER:
212 	case SNDRV_DEVICE_TYPE_TIMER:
213 		minor = type;
214 		break;
215 	case SNDRV_DEVICE_TYPE_CONTROL:
216 		if (snd_BUG_ON(!card))
217 			return -EINVAL;
218 		minor = SNDRV_MINOR(card->number, type);
219 		break;
220 	case SNDRV_DEVICE_TYPE_HWDEP:
221 	case SNDRV_DEVICE_TYPE_RAWMIDI:
222 	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
223 	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
224 		if (snd_BUG_ON(!card))
225 			return -EINVAL;
226 		minor = SNDRV_MINOR(card->number, type + dev);
227 		break;
228 	default:
229 		return -EINVAL;
230 	}
231 	if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
232 		return -EINVAL;
233 	return minor;
234 }
235 #endif
236 
237 /**
238  * snd_register_device_for_dev - Register the ALSA device file for the card
239  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
240  * @card: the card instance
241  * @dev: the device index
242  * @f_ops: the file operations
243  * @private_data: user pointer for f_ops->open()
244  * @name: the device file name
245  * @device: the &struct device to link this new device to
246  *
247  * Registers an ALSA device file for the given card.
248  * The operators have to be set in reg parameter.
249  *
250  * Returns zero if successful, or a negative error code on failure.
251  */
252 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
253 				const struct file_operations *f_ops,
254 				void *private_data,
255 				const char *name, struct device *device)
256 {
257 	int minor;
258 	struct snd_minor *preg;
259 
260 	if (snd_BUG_ON(!name))
261 		return -EINVAL;
262 	preg = kmalloc(sizeof *preg, GFP_KERNEL);
263 	if (preg == NULL)
264 		return -ENOMEM;
265 	preg->type = type;
266 	preg->card = card ? card->number : -1;
267 	preg->device = dev;
268 	preg->f_ops = f_ops;
269 	preg->private_data = private_data;
270 	mutex_lock(&sound_mutex);
271 #ifdef CONFIG_SND_DYNAMIC_MINORS
272 	minor = snd_find_free_minor();
273 #else
274 	minor = snd_kernel_minor(type, card, dev);
275 	if (minor >= 0 && snd_minors[minor])
276 		minor = -EBUSY;
277 #endif
278 	if (minor < 0) {
279 		mutex_unlock(&sound_mutex);
280 		kfree(preg);
281 		return minor;
282 	}
283 	snd_minors[minor] = preg;
284 	preg->dev = device_create(sound_class, device, MKDEV(major, minor),
285 				  private_data, "%s", name);
286 	if (IS_ERR(preg->dev)) {
287 		snd_minors[minor] = NULL;
288 		mutex_unlock(&sound_mutex);
289 		minor = PTR_ERR(preg->dev);
290 		kfree(preg);
291 		return minor;
292 	}
293 
294 	mutex_unlock(&sound_mutex);
295 	return 0;
296 }
297 
298 EXPORT_SYMBOL(snd_register_device_for_dev);
299 
300 /* find the matching minor record
301  * return the index of snd_minor, or -1 if not found
302  */
303 static int find_snd_minor(int type, struct snd_card *card, int dev)
304 {
305 	int cardnum, minor;
306 	struct snd_minor *mptr;
307 
308 	cardnum = card ? card->number : -1;
309 	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
310 		if ((mptr = snd_minors[minor]) != NULL &&
311 		    mptr->type == type &&
312 		    mptr->card == cardnum &&
313 		    mptr->device == dev)
314 			return minor;
315 	return -1;
316 }
317 
318 /**
319  * snd_unregister_device - unregister the device on the given card
320  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
321  * @card: the card instance
322  * @dev: the device index
323  *
324  * Unregisters the device file already registered via
325  * snd_register_device().
326  *
327  * Returns zero if sucecessful, or a negative error code on failure
328  */
329 int snd_unregister_device(int type, struct snd_card *card, int dev)
330 {
331 	int minor;
332 
333 	mutex_lock(&sound_mutex);
334 	minor = find_snd_minor(type, card, dev);
335 	if (minor < 0) {
336 		mutex_unlock(&sound_mutex);
337 		return -EINVAL;
338 	}
339 
340 	device_destroy(sound_class, MKDEV(major, minor));
341 
342 	kfree(snd_minors[minor]);
343 	snd_minors[minor] = NULL;
344 	mutex_unlock(&sound_mutex);
345 	return 0;
346 }
347 
348 EXPORT_SYMBOL(snd_unregister_device);
349 
350 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
351 			      struct device_attribute *attr)
352 {
353 	int minor, ret = -EINVAL;
354 	struct device *d;
355 
356 	mutex_lock(&sound_mutex);
357 	minor = find_snd_minor(type, card, dev);
358 	if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
359 		ret = device_create_file(d, attr);
360 	mutex_unlock(&sound_mutex);
361 	return ret;
362 
363 }
364 
365 EXPORT_SYMBOL(snd_add_device_sysfs_file);
366 
367 #ifdef CONFIG_PROC_FS
368 /*
369  *  INFO PART
370  */
371 
372 static struct snd_info_entry *snd_minor_info_entry;
373 
374 static const char *snd_device_type_name(int type)
375 {
376 	switch (type) {
377 	case SNDRV_DEVICE_TYPE_CONTROL:
378 		return "control";
379 	case SNDRV_DEVICE_TYPE_HWDEP:
380 		return "hardware dependent";
381 	case SNDRV_DEVICE_TYPE_RAWMIDI:
382 		return "raw midi";
383 	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
384 		return "digital audio playback";
385 	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
386 		return "digital audio capture";
387 	case SNDRV_DEVICE_TYPE_SEQUENCER:
388 		return "sequencer";
389 	case SNDRV_DEVICE_TYPE_TIMER:
390 		return "timer";
391 	default:
392 		return "?";
393 	}
394 }
395 
396 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
397 {
398 	int minor;
399 	struct snd_minor *mptr;
400 
401 	mutex_lock(&sound_mutex);
402 	for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
403 		if (!(mptr = snd_minors[minor]))
404 			continue;
405 		if (mptr->card >= 0) {
406 			if (mptr->device >= 0)
407 				snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
408 					    minor, mptr->card, mptr->device,
409 					    snd_device_type_name(mptr->type));
410 			else
411 				snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
412 					    minor, mptr->card,
413 					    snd_device_type_name(mptr->type));
414 		} else
415 			snd_iprintf(buffer, "%3i:        : %s\n", minor,
416 				    snd_device_type_name(mptr->type));
417 	}
418 	mutex_unlock(&sound_mutex);
419 }
420 
421 int __init snd_minor_info_init(void)
422 {
423 	struct snd_info_entry *entry;
424 
425 	entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
426 	if (entry) {
427 		entry->c.text.read = snd_minor_info_read;
428 		if (snd_info_register(entry) < 0) {
429 			snd_info_free_entry(entry);
430 			entry = NULL;
431 		}
432 	}
433 	snd_minor_info_entry = entry;
434 	return 0;
435 }
436 
437 int __exit snd_minor_info_done(void)
438 {
439 	snd_info_free_entry(snd_minor_info_entry);
440 	return 0;
441 }
442 #endif /* CONFIG_PROC_FS */
443 
444 /*
445  *  INIT PART
446  */
447 
448 static int __init alsa_sound_init(void)
449 {
450 	snd_major = major;
451 	snd_ecards_limit = cards_limit;
452 	if (register_chrdev(major, "alsa", &snd_fops)) {
453 		snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
454 		return -EIO;
455 	}
456 	if (snd_info_init() < 0) {
457 		unregister_chrdev(major, "alsa");
458 		return -ENOMEM;
459 	}
460 	snd_info_minor_register();
461 #ifndef MODULE
462 	printk(KERN_INFO "Advanced Linux Sound Architecture Driver Version " CONFIG_SND_VERSION CONFIG_SND_DATE ".\n");
463 #endif
464 	return 0;
465 }
466 
467 static void __exit alsa_sound_exit(void)
468 {
469 	snd_info_minor_unregister();
470 	snd_info_done();
471 	unregister_chrdev(major, "alsa");
472 }
473 
474 subsys_initcall(alsa_sound_init);
475 module_exit(alsa_sound_exit);
476