xref: /openbmc/linux/sound/core/sound.c (revision 367b8112) 
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 static int __snd_open(struct inode *inode, struct file *file)
124 {
125 	unsigned int minor = iminor(inode);
126 	struct snd_minor *mptr = NULL;
127 	const struct file_operations *old_fops;
128 	int err = 0;
129 
130 	if (minor >= ARRAY_SIZE(snd_minors))
131 		return -ENODEV;
132 	mptr = snd_minors[minor];
133 	if (mptr == NULL) {
134 #ifdef CONFIG_MODULES
135 		int dev = SNDRV_MINOR_DEVICE(minor);
136 		if (dev == SNDRV_MINOR_CONTROL) {
137 			/* /dev/aloadC? */
138 			int card = SNDRV_MINOR_CARD(minor);
139 			if (snd_cards[card] == NULL)
140 				snd_request_card(card);
141 		} else if (dev == SNDRV_MINOR_GLOBAL) {
142 			/* /dev/aloadSEQ */
143 			snd_request_other(minor);
144 		}
145 #ifndef CONFIG_SND_DYNAMIC_MINORS
146 		/* /dev/snd/{controlC?,seq} */
147 		mptr = snd_minors[minor];
148 		if (mptr == NULL)
149 #endif
150 #endif
151 			return -ENODEV;
152 	}
153 	old_fops = file->f_op;
154 	file->f_op = fops_get(mptr->f_ops);
155 	if (file->f_op->open)
156 		err = file->f_op->open(inode, file);
157 	if (err) {
158 		fops_put(file->f_op);
159 		file->f_op = fops_get(old_fops);
160 	}
161 	fops_put(old_fops);
162 	return err;
163 }
164 
165 
166 /* BKL pushdown: nasty #ifdef avoidance wrapper */
167 static int snd_open(struct inode *inode, struct file *file)
168 {
169 	int ret;
170 
171 	lock_kernel();
172 	ret = __snd_open(inode, file);
173 	unlock_kernel();
174 	return ret;
175 }
176 
177 static const struct file_operations snd_fops =
178 {
179 	.owner =	THIS_MODULE,
180 	.open =		snd_open
181 };
182 
183 #ifdef CONFIG_SND_DYNAMIC_MINORS
184 static int snd_find_free_minor(void)
185 {
186 	int minor;
187 
188 	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
189 		/* skip minors still used statically for autoloading devices */
190 		if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL ||
191 		    minor == SNDRV_MINOR_SEQUENCER)
192 			continue;
193 		if (!snd_minors[minor])
194 			return minor;
195 	}
196 	return -EBUSY;
197 }
198 #else
199 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
200 {
201 	int minor;
202 
203 	switch (type) {
204 	case SNDRV_DEVICE_TYPE_SEQUENCER:
205 	case SNDRV_DEVICE_TYPE_TIMER:
206 		minor = type;
207 		break;
208 	case SNDRV_DEVICE_TYPE_CONTROL:
209 		if (snd_BUG_ON(!card))
210 			return -EINVAL;
211 		minor = SNDRV_MINOR(card->number, type);
212 		break;
213 	case SNDRV_DEVICE_TYPE_HWDEP:
214 	case SNDRV_DEVICE_TYPE_RAWMIDI:
215 	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
216 	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
217 		if (snd_BUG_ON(!card))
218 			return -EINVAL;
219 		minor = SNDRV_MINOR(card->number, type + dev);
220 		break;
221 	default:
222 		return -EINVAL;
223 	}
224 	if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
225 		return -EINVAL;
226 	return minor;
227 }
228 #endif
229 
230 /**
231  * snd_register_device_for_dev - Register the ALSA device file for the card
232  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
233  * @card: the card instance
234  * @dev: the device index
235  * @f_ops: the file operations
236  * @private_data: user pointer for f_ops->open()
237  * @name: the device file name
238  * @device: the &struct device to link this new device to
239  *
240  * Registers an ALSA device file for the given card.
241  * The operators have to be set in reg parameter.
242  *
243  * Returns zero if successful, or a negative error code on failure.
244  */
245 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
246 				const struct file_operations *f_ops,
247 				void *private_data,
248 				const char *name, struct device *device)
249 {
250 	int minor;
251 	struct snd_minor *preg;
252 
253 	if (snd_BUG_ON(!name))
254 		return -EINVAL;
255 	preg = kmalloc(sizeof *preg, GFP_KERNEL);
256 	if (preg == NULL)
257 		return -ENOMEM;
258 	preg->type = type;
259 	preg->card = card ? card->number : -1;
260 	preg->device = dev;
261 	preg->f_ops = f_ops;
262 	preg->private_data = private_data;
263 	mutex_lock(&sound_mutex);
264 #ifdef CONFIG_SND_DYNAMIC_MINORS
265 	minor = snd_find_free_minor();
266 #else
267 	minor = snd_kernel_minor(type, card, dev);
268 	if (minor >= 0 && snd_minors[minor])
269 		minor = -EBUSY;
270 #endif
271 	if (minor < 0) {
272 		mutex_unlock(&sound_mutex);
273 		kfree(preg);
274 		return minor;
275 	}
276 	snd_minors[minor] = preg;
277 	preg->dev = device_create(sound_class, device, MKDEV(major, minor),
278 				  private_data, "%s", name);
279 	if (IS_ERR(preg->dev)) {
280 		snd_minors[minor] = NULL;
281 		mutex_unlock(&sound_mutex);
282 		minor = PTR_ERR(preg->dev);
283 		kfree(preg);
284 		return minor;
285 	}
286 
287 	mutex_unlock(&sound_mutex);
288 	return 0;
289 }
290 
291 EXPORT_SYMBOL(snd_register_device_for_dev);
292 
293 /* find the matching minor record
294  * return the index of snd_minor, or -1 if not found
295  */
296 static int find_snd_minor(int type, struct snd_card *card, int dev)
297 {
298 	int cardnum, minor;
299 	struct snd_minor *mptr;
300 
301 	cardnum = card ? card->number : -1;
302 	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
303 		if ((mptr = snd_minors[minor]) != NULL &&
304 		    mptr->type == type &&
305 		    mptr->card == cardnum &&
306 		    mptr->device == dev)
307 			return minor;
308 	return -1;
309 }
310 
311 /**
312  * snd_unregister_device - unregister the device on the given card
313  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
314  * @card: the card instance
315  * @dev: the device index
316  *
317  * Unregisters the device file already registered via
318  * snd_register_device().
319  *
320  * Returns zero if sucecessful, or a negative error code on failure
321  */
322 int snd_unregister_device(int type, struct snd_card *card, int dev)
323 {
324 	int minor;
325 
326 	mutex_lock(&sound_mutex);
327 	minor = find_snd_minor(type, card, dev);
328 	if (minor < 0) {
329 		mutex_unlock(&sound_mutex);
330 		return -EINVAL;
331 	}
332 
333 	device_destroy(sound_class, MKDEV(major, minor));
334 
335 	kfree(snd_minors[minor]);
336 	snd_minors[minor] = NULL;
337 	mutex_unlock(&sound_mutex);
338 	return 0;
339 }
340 
341 EXPORT_SYMBOL(snd_unregister_device);
342 
343 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
344 			      struct device_attribute *attr)
345 {
346 	int minor, ret = -EINVAL;
347 	struct device *d;
348 
349 	mutex_lock(&sound_mutex);
350 	minor = find_snd_minor(type, card, dev);
351 	if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
352 		ret = device_create_file(d, attr);
353 	mutex_unlock(&sound_mutex);
354 	return ret;
355 
356 }
357 
358 EXPORT_SYMBOL(snd_add_device_sysfs_file);
359 
360 #ifdef CONFIG_PROC_FS
361 /*
362  *  INFO PART
363  */
364 
365 static struct snd_info_entry *snd_minor_info_entry;
366 
367 static const char *snd_device_type_name(int type)
368 {
369 	switch (type) {
370 	case SNDRV_DEVICE_TYPE_CONTROL:
371 		return "control";
372 	case SNDRV_DEVICE_TYPE_HWDEP:
373 		return "hardware dependent";
374 	case SNDRV_DEVICE_TYPE_RAWMIDI:
375 		return "raw midi";
376 	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
377 		return "digital audio playback";
378 	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
379 		return "digital audio capture";
380 	case SNDRV_DEVICE_TYPE_SEQUENCER:
381 		return "sequencer";
382 	case SNDRV_DEVICE_TYPE_TIMER:
383 		return "timer";
384 	default:
385 		return "?";
386 	}
387 }
388 
389 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
390 {
391 	int minor;
392 	struct snd_minor *mptr;
393 
394 	mutex_lock(&sound_mutex);
395 	for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
396 		if (!(mptr = snd_minors[minor]))
397 			continue;
398 		if (mptr->card >= 0) {
399 			if (mptr->device >= 0)
400 				snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
401 					    minor, mptr->card, mptr->device,
402 					    snd_device_type_name(mptr->type));
403 			else
404 				snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
405 					    minor, mptr->card,
406 					    snd_device_type_name(mptr->type));
407 		} else
408 			snd_iprintf(buffer, "%3i:        : %s\n", minor,
409 				    snd_device_type_name(mptr->type));
410 	}
411 	mutex_unlock(&sound_mutex);
412 }
413 
414 int __init snd_minor_info_init(void)
415 {
416 	struct snd_info_entry *entry;
417 
418 	entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
419 	if (entry) {
420 		entry->c.text.read = snd_minor_info_read;
421 		if (snd_info_register(entry) < 0) {
422 			snd_info_free_entry(entry);
423 			entry = NULL;
424 		}
425 	}
426 	snd_minor_info_entry = entry;
427 	return 0;
428 }
429 
430 int __exit snd_minor_info_done(void)
431 {
432 	snd_info_free_entry(snd_minor_info_entry);
433 	return 0;
434 }
435 #endif /* CONFIG_PROC_FS */
436 
437 /*
438  *  INIT PART
439  */
440 
441 static int __init alsa_sound_init(void)
442 {
443 	snd_major = major;
444 	snd_ecards_limit = cards_limit;
445 	if (register_chrdev(major, "alsa", &snd_fops)) {
446 		snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
447 		return -EIO;
448 	}
449 	if (snd_info_init() < 0) {
450 		unregister_chrdev(major, "alsa");
451 		return -ENOMEM;
452 	}
453 	snd_info_minor_register();
454 #ifndef MODULE
455 	printk(KERN_INFO "Advanced Linux Sound Architecture Driver Version " CONFIG_SND_VERSION CONFIG_SND_DATE ".\n");
456 #endif
457 	return 0;
458 }
459 
460 static void __exit alsa_sound_exit(void)
461 {
462 	snd_info_minor_unregister();
463 	snd_info_done();
464 	unregister_chrdev(major, "alsa");
465 }
466 
467 module_init(alsa_sound_init)
468 module_exit(alsa_sound_exit)
469