xref: /openbmc/linux/sound/core/sound.c (revision b6dcefde) 
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 == NULL) {
156 		file->f_op = old_fops;
157 		return -ENODEV;
158 	}
159 	if (file->f_op->open)
160 		err = file->f_op->open(inode, file);
161 	if (err) {
162 		fops_put(file->f_op);
163 		file->f_op = fops_get(old_fops);
164 	}
165 	fops_put(old_fops);
166 	return err;
167 }
168 
169 
170 /* BKL pushdown: nasty #ifdef avoidance wrapper */
171 static int snd_open(struct inode *inode, struct file *file)
172 {
173 	int ret;
174 
175 	lock_kernel();
176 	ret = __snd_open(inode, file);
177 	unlock_kernel();
178 	return ret;
179 }
180 
181 static const struct file_operations snd_fops =
182 {
183 	.owner =	THIS_MODULE,
184 	.open =		snd_open
185 };
186 
187 #ifdef CONFIG_SND_DYNAMIC_MINORS
188 static int snd_find_free_minor(void)
189 {
190 	int minor;
191 
192 	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
193 		/* skip minors still used statically for autoloading devices */
194 		if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL ||
195 		    minor == SNDRV_MINOR_SEQUENCER)
196 			continue;
197 		if (!snd_minors[minor])
198 			return minor;
199 	}
200 	return -EBUSY;
201 }
202 #else
203 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
204 {
205 	int minor;
206 
207 	switch (type) {
208 	case SNDRV_DEVICE_TYPE_SEQUENCER:
209 	case SNDRV_DEVICE_TYPE_TIMER:
210 		minor = type;
211 		break;
212 	case SNDRV_DEVICE_TYPE_CONTROL:
213 		if (snd_BUG_ON(!card))
214 			return -EINVAL;
215 		minor = SNDRV_MINOR(card->number, type);
216 		break;
217 	case SNDRV_DEVICE_TYPE_HWDEP:
218 	case SNDRV_DEVICE_TYPE_RAWMIDI:
219 	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
220 	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
221 		if (snd_BUG_ON(!card))
222 			return -EINVAL;
223 		minor = SNDRV_MINOR(card->number, type + dev);
224 		break;
225 	default:
226 		return -EINVAL;
227 	}
228 	if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
229 		return -EINVAL;
230 	return minor;
231 }
232 #endif
233 
234 /**
235  * snd_register_device_for_dev - Register the ALSA device file for the card
236  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
237  * @card: the card instance
238  * @dev: the device index
239  * @f_ops: the file operations
240  * @private_data: user pointer for f_ops->open()
241  * @name: the device file name
242  * @device: the &struct device to link this new device to
243  *
244  * Registers an ALSA device file for the given card.
245  * The operators have to be set in reg parameter.
246  *
247  * Returns zero if successful, or a negative error code on failure.
248  */
249 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
250 				const struct file_operations *f_ops,
251 				void *private_data,
252 				const char *name, struct device *device)
253 {
254 	int minor;
255 	struct snd_minor *preg;
256 
257 	if (snd_BUG_ON(!name))
258 		return -EINVAL;
259 	preg = kmalloc(sizeof *preg, GFP_KERNEL);
260 	if (preg == NULL)
261 		return -ENOMEM;
262 	preg->type = type;
263 	preg->card = card ? card->number : -1;
264 	preg->device = dev;
265 	preg->f_ops = f_ops;
266 	preg->private_data = private_data;
267 	mutex_lock(&sound_mutex);
268 #ifdef CONFIG_SND_DYNAMIC_MINORS
269 	minor = snd_find_free_minor();
270 #else
271 	minor = snd_kernel_minor(type, card, dev);
272 	if (minor >= 0 && snd_minors[minor])
273 		minor = -EBUSY;
274 #endif
275 	if (minor < 0) {
276 		mutex_unlock(&sound_mutex);
277 		kfree(preg);
278 		return minor;
279 	}
280 	snd_minors[minor] = preg;
281 	preg->dev = device_create(sound_class, device, MKDEV(major, minor),
282 				  private_data, "%s", name);
283 	if (IS_ERR(preg->dev)) {
284 		snd_minors[minor] = NULL;
285 		mutex_unlock(&sound_mutex);
286 		minor = PTR_ERR(preg->dev);
287 		kfree(preg);
288 		return minor;
289 	}
290 
291 	mutex_unlock(&sound_mutex);
292 	return 0;
293 }
294 
295 EXPORT_SYMBOL(snd_register_device_for_dev);
296 
297 /* find the matching minor record
298  * return the index of snd_minor, or -1 if not found
299  */
300 static int find_snd_minor(int type, struct snd_card *card, int dev)
301 {
302 	int cardnum, minor;
303 	struct snd_minor *mptr;
304 
305 	cardnum = card ? card->number : -1;
306 	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
307 		if ((mptr = snd_minors[minor]) != NULL &&
308 		    mptr->type == type &&
309 		    mptr->card == cardnum &&
310 		    mptr->device == dev)
311 			return minor;
312 	return -1;
313 }
314 
315 /**
316  * snd_unregister_device - unregister the device on the given card
317  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
318  * @card: the card instance
319  * @dev: the device index
320  *
321  * Unregisters the device file already registered via
322  * snd_register_device().
323  *
324  * Returns zero if sucecessful, or a negative error code on failure
325  */
326 int snd_unregister_device(int type, struct snd_card *card, int dev)
327 {
328 	int minor;
329 
330 	mutex_lock(&sound_mutex);
331 	minor = find_snd_minor(type, card, dev);
332 	if (minor < 0) {
333 		mutex_unlock(&sound_mutex);
334 		return -EINVAL;
335 	}
336 
337 	device_destroy(sound_class, MKDEV(major, minor));
338 
339 	kfree(snd_minors[minor]);
340 	snd_minors[minor] = NULL;
341 	mutex_unlock(&sound_mutex);
342 	return 0;
343 }
344 
345 EXPORT_SYMBOL(snd_unregister_device);
346 
347 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
348 			      struct device_attribute *attr)
349 {
350 	int minor, ret = -EINVAL;
351 	struct device *d;
352 
353 	mutex_lock(&sound_mutex);
354 	minor = find_snd_minor(type, card, dev);
355 	if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
356 		ret = device_create_file(d, attr);
357 	mutex_unlock(&sound_mutex);
358 	return ret;
359 
360 }
361 
362 EXPORT_SYMBOL(snd_add_device_sysfs_file);
363 
364 #ifdef CONFIG_PROC_FS
365 /*
366  *  INFO PART
367  */
368 
369 static struct snd_info_entry *snd_minor_info_entry;
370 
371 static const char *snd_device_type_name(int type)
372 {
373 	switch (type) {
374 	case SNDRV_DEVICE_TYPE_CONTROL:
375 		return "control";
376 	case SNDRV_DEVICE_TYPE_HWDEP:
377 		return "hardware dependent";
378 	case SNDRV_DEVICE_TYPE_RAWMIDI:
379 		return "raw midi";
380 	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
381 		return "digital audio playback";
382 	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
383 		return "digital audio capture";
384 	case SNDRV_DEVICE_TYPE_SEQUENCER:
385 		return "sequencer";
386 	case SNDRV_DEVICE_TYPE_TIMER:
387 		return "timer";
388 	default:
389 		return "?";
390 	}
391 }
392 
393 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
394 {
395 	int minor;
396 	struct snd_minor *mptr;
397 
398 	mutex_lock(&sound_mutex);
399 	for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
400 		if (!(mptr = snd_minors[minor]))
401 			continue;
402 		if (mptr->card >= 0) {
403 			if (mptr->device >= 0)
404 				snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
405 					    minor, mptr->card, mptr->device,
406 					    snd_device_type_name(mptr->type));
407 			else
408 				snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
409 					    minor, mptr->card,
410 					    snd_device_type_name(mptr->type));
411 		} else
412 			snd_iprintf(buffer, "%3i:        : %s\n", minor,
413 				    snd_device_type_name(mptr->type));
414 	}
415 	mutex_unlock(&sound_mutex);
416 }
417 
418 int __init snd_minor_info_init(void)
419 {
420 	struct snd_info_entry *entry;
421 
422 	entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
423 	if (entry) {
424 		entry->c.text.read = snd_minor_info_read;
425 		if (snd_info_register(entry) < 0) {
426 			snd_info_free_entry(entry);
427 			entry = NULL;
428 		}
429 	}
430 	snd_minor_info_entry = entry;
431 	return 0;
432 }
433 
434 int __exit snd_minor_info_done(void)
435 {
436 	snd_info_free_entry(snd_minor_info_entry);
437 	return 0;
438 }
439 #endif /* CONFIG_PROC_FS */
440 
441 /*
442  *  INIT PART
443  */
444 
445 static int __init alsa_sound_init(void)
446 {
447 	snd_major = major;
448 	snd_ecards_limit = cards_limit;
449 	if (register_chrdev(major, "alsa", &snd_fops)) {
450 		snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
451 		return -EIO;
452 	}
453 	if (snd_info_init() < 0) {
454 		unregister_chrdev(major, "alsa");
455 		return -ENOMEM;
456 	}
457 	snd_info_minor_register();
458 #ifndef MODULE
459 	printk(KERN_INFO "Advanced Linux Sound Architecture Driver Version " CONFIG_SND_VERSION CONFIG_SND_DATE ".\n");
460 #endif
461 	return 0;
462 }
463 
464 static void __exit alsa_sound_exit(void)
465 {
466 	snd_info_minor_unregister();
467 	snd_info_done();
468 	unregister_chrdev(major, "alsa");
469 }
470 
471 subsys_initcall(alsa_sound_init);
472 module_exit(alsa_sound_exit);
473