xref: /openbmc/linux/sound/core/sound.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2  *  Advanced Linux Sound Architecture
3  *  Copyright (c) by Jaroslav Kysela <perex@suse.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 <sound/driver.h>
23 #include <linux/init.h>
24 #include <linux/slab.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 #define SNDRV_OS_MINORS 256
38 
39 static int major = CONFIG_SND_MAJOR;
40 int snd_major;
41 EXPORT_SYMBOL(snd_major);
42 
43 static int cards_limit = 1;
44 
45 MODULE_AUTHOR("Jaroslav Kysela <perex@suse.cz>");
46 MODULE_DESCRIPTION("Advanced Linux Sound Architecture driver for soundcards.");
47 MODULE_LICENSE("GPL");
48 module_param(major, int, 0444);
49 MODULE_PARM_DESC(major, "Major # for sound driver.");
50 module_param(cards_limit, int, 0444);
51 MODULE_PARM_DESC(cards_limit, "Count of auto-loadable soundcards.");
52 MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR);
53 
54 /* this one holds the actual max. card number currently available.
55  * as default, it's identical with cards_limit option.  when more
56  * modules are loaded manually, this limit number increases, too.
57  */
58 int snd_ecards_limit;
59 EXPORT_SYMBOL(snd_ecards_limit);
60 
61 static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
62 static DEFINE_MUTEX(sound_mutex);
63 
64 #ifdef CONFIG_KMOD
65 
66 /**
67  * snd_request_card - try to load the card module
68  * @card: the card number
69  *
70  * Tries to load the module "snd-card-X" for the given card number
71  * via KMOD.  Returns immediately if already loaded.
72  */
73 void snd_request_card(int card)
74 {
75 	if (! current->fs->root)
76 		return;
77 	if (snd_card_locked(card))
78 		return;
79 	if (card < 0 || card >= cards_limit)
80 		return;
81 	request_module("snd-card-%i", card);
82 }
83 
84 EXPORT_SYMBOL(snd_request_card);
85 
86 static void snd_request_other(int minor)
87 {
88 	char *str;
89 
90 	if (! current->fs->root)
91 		return;
92 	switch (minor) {
93 	case SNDRV_MINOR_SEQUENCER:	str = "snd-seq";	break;
94 	case SNDRV_MINOR_TIMER:		str = "snd-timer";	break;
95 	default:			return;
96 	}
97 	request_module(str);
98 }
99 
100 #endif				/* request_module support */
101 
102 /**
103  * snd_lookup_minor_data - get user data of a registered device
104  * @minor: the minor number
105  * @type: device type (SNDRV_DEVICE_TYPE_XXX)
106  *
107  * Checks that a minor device with the specified type is registered, and returns
108  * its user data pointer.
109  */
110 void *snd_lookup_minor_data(unsigned int minor, int type)
111 {
112 	struct snd_minor *mreg;
113 	void *private_data;
114 
115 	if (minor >= ARRAY_SIZE(snd_minors))
116 		return NULL;
117 	mutex_lock(&sound_mutex);
118 	mreg = snd_minors[minor];
119 	if (mreg && mreg->type == type)
120 		private_data = mreg->private_data;
121 	else
122 		private_data = NULL;
123 	mutex_unlock(&sound_mutex);
124 	return private_data;
125 }
126 
127 EXPORT_SYMBOL(snd_lookup_minor_data);
128 
129 static int snd_open(struct inode *inode, struct file *file)
130 {
131 	unsigned int minor = iminor(inode);
132 	struct snd_minor *mptr = NULL;
133 	const struct file_operations *old_fops;
134 	int err = 0;
135 
136 	if (minor >= ARRAY_SIZE(snd_minors))
137 		return -ENODEV;
138 	mptr = snd_minors[minor];
139 	if (mptr == NULL) {
140 #ifdef CONFIG_KMOD
141 		int dev = SNDRV_MINOR_DEVICE(minor);
142 		if (dev == SNDRV_MINOR_CONTROL) {
143 			/* /dev/aloadC? */
144 			int card = SNDRV_MINOR_CARD(minor);
145 			if (snd_cards[card] == NULL)
146 				snd_request_card(card);
147 		} else if (dev == SNDRV_MINOR_GLOBAL) {
148 			/* /dev/aloadSEQ */
149 			snd_request_other(minor);
150 		}
151 #ifndef CONFIG_SND_DYNAMIC_MINORS
152 		/* /dev/snd/{controlC?,seq} */
153 		mptr = snd_minors[minor];
154 		if (mptr == NULL)
155 #endif
156 #endif
157 			return -ENODEV;
158 	}
159 	old_fops = file->f_op;
160 	file->f_op = fops_get(mptr->f_ops);
161 	if (file->f_op->open)
162 		err = file->f_op->open(inode, file);
163 	if (err) {
164 		fops_put(file->f_op);
165 		file->f_op = fops_get(old_fops);
166 	}
167 	fops_put(old_fops);
168 	return err;
169 }
170 
171 static const struct file_operations snd_fops =
172 {
173 	.owner =	THIS_MODULE,
174 	.open =		snd_open
175 };
176 
177 #ifdef CONFIG_SND_DYNAMIC_MINORS
178 static int snd_find_free_minor(void)
179 {
180 	int minor;
181 
182 	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
183 		/* skip minors still used statically for autoloading devices */
184 		if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL ||
185 		    minor == SNDRV_MINOR_SEQUENCER)
186 			continue;
187 		if (!snd_minors[minor])
188 			return minor;
189 	}
190 	return -EBUSY;
191 }
192 #else
193 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
194 {
195 	int minor;
196 
197 	switch (type) {
198 	case SNDRV_DEVICE_TYPE_SEQUENCER:
199 	case SNDRV_DEVICE_TYPE_TIMER:
200 		minor = type;
201 		break;
202 	case SNDRV_DEVICE_TYPE_CONTROL:
203 		snd_assert(card != NULL, return -EINVAL);
204 		minor = SNDRV_MINOR(card->number, type);
205 		break;
206 	case SNDRV_DEVICE_TYPE_HWDEP:
207 	case SNDRV_DEVICE_TYPE_RAWMIDI:
208 	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
209 	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
210 		snd_assert(card != NULL, return -EINVAL);
211 		minor = SNDRV_MINOR(card->number, type + dev);
212 		break;
213 	default:
214 		return -EINVAL;
215 	}
216 	snd_assert(minor >= 0 && minor < SNDRV_OS_MINORS, return -EINVAL);
217 	return minor;
218 }
219 #endif
220 
221 /**
222  * snd_register_device_for_dev - Register the ALSA device file for the card
223  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
224  * @card: the card instance
225  * @dev: the device index
226  * @f_ops: the file operations
227  * @private_data: user pointer for f_ops->open()
228  * @name: the device file name
229  * @device: the &struct device to link this new device to
230  *
231  * Registers an ALSA device file for the given card.
232  * The operators have to be set in reg parameter.
233  *
234  * Returns zero if successful, or a negative error code on failure.
235  */
236 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
237 				const struct file_operations *f_ops,
238 				void *private_data,
239 				const char *name, struct device *device)
240 {
241 	int minor;
242 	struct snd_minor *preg;
243 
244 	snd_assert(name, return -EINVAL);
245 	preg = kmalloc(sizeof *preg, GFP_KERNEL);
246 	if (preg == NULL)
247 		return -ENOMEM;
248 	preg->type = type;
249 	preg->card = card ? card->number : -1;
250 	preg->device = dev;
251 	preg->f_ops = f_ops;
252 	preg->private_data = private_data;
253 	mutex_lock(&sound_mutex);
254 #ifdef CONFIG_SND_DYNAMIC_MINORS
255 	minor = snd_find_free_minor();
256 #else
257 	minor = snd_kernel_minor(type, card, dev);
258 	if (minor >= 0 && snd_minors[minor])
259 		minor = -EBUSY;
260 #endif
261 	if (minor < 0) {
262 		mutex_unlock(&sound_mutex);
263 		kfree(preg);
264 		return minor;
265 	}
266 	snd_minors[minor] = preg;
267 	preg->dev = device_create(sound_class, device, MKDEV(major, minor),
268 				  "%s", name);
269 	if (preg->dev)
270 		dev_set_drvdata(preg->dev, private_data);
271 
272 	mutex_unlock(&sound_mutex);
273 	return 0;
274 }
275 
276 EXPORT_SYMBOL(snd_register_device_for_dev);
277 
278 /* find the matching minor record
279  * return the index of snd_minor, or -1 if not found
280  */
281 static int find_snd_minor(int type, struct snd_card *card, int dev)
282 {
283 	int cardnum, minor;
284 	struct snd_minor *mptr;
285 
286 	cardnum = card ? card->number : -1;
287 	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
288 		if ((mptr = snd_minors[minor]) != NULL &&
289 		    mptr->type == type &&
290 		    mptr->card == cardnum &&
291 		    mptr->device == dev)
292 			return minor;
293 	return -1;
294 }
295 
296 /**
297  * snd_unregister_device - unregister the device on the given card
298  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
299  * @card: the card instance
300  * @dev: the device index
301  *
302  * Unregisters the device file already registered via
303  * snd_register_device().
304  *
305  * Returns zero if sucecessful, or a negative error code on failure
306  */
307 int snd_unregister_device(int type, struct snd_card *card, int dev)
308 {
309 	int minor;
310 
311 	mutex_lock(&sound_mutex);
312 	minor = find_snd_minor(type, card, dev);
313 	if (minor < 0) {
314 		mutex_unlock(&sound_mutex);
315 		return -EINVAL;
316 	}
317 
318 	device_destroy(sound_class, MKDEV(major, minor));
319 
320 	kfree(snd_minors[minor]);
321 	snd_minors[minor] = NULL;
322 	mutex_unlock(&sound_mutex);
323 	return 0;
324 }
325 
326 EXPORT_SYMBOL(snd_unregister_device);
327 
328 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
329 			      struct device_attribute *attr)
330 {
331 	int minor, ret = -EINVAL;
332 	struct device *d;
333 
334 	mutex_lock(&sound_mutex);
335 	minor = find_snd_minor(type, card, dev);
336 	if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
337 		ret = device_create_file(d, attr);
338 	mutex_unlock(&sound_mutex);
339 	return ret;
340 
341 }
342 
343 EXPORT_SYMBOL(snd_add_device_sysfs_file);
344 
345 #ifdef CONFIG_PROC_FS
346 /*
347  *  INFO PART
348  */
349 
350 static struct snd_info_entry *snd_minor_info_entry;
351 
352 static const char *snd_device_type_name(int type)
353 {
354 	switch (type) {
355 	case SNDRV_DEVICE_TYPE_CONTROL:
356 		return "control";
357 	case SNDRV_DEVICE_TYPE_HWDEP:
358 		return "hardware dependent";
359 	case SNDRV_DEVICE_TYPE_RAWMIDI:
360 		return "raw midi";
361 	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
362 		return "digital audio playback";
363 	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
364 		return "digital audio capture";
365 	case SNDRV_DEVICE_TYPE_SEQUENCER:
366 		return "sequencer";
367 	case SNDRV_DEVICE_TYPE_TIMER:
368 		return "timer";
369 	default:
370 		return "?";
371 	}
372 }
373 
374 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
375 {
376 	int minor;
377 	struct snd_minor *mptr;
378 
379 	mutex_lock(&sound_mutex);
380 	for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
381 		if (!(mptr = snd_minors[minor]))
382 			continue;
383 		if (mptr->card >= 0) {
384 			if (mptr->device >= 0)
385 				snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
386 					    minor, mptr->card, mptr->device,
387 					    snd_device_type_name(mptr->type));
388 			else
389 				snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
390 					    minor, mptr->card,
391 					    snd_device_type_name(mptr->type));
392 		} else
393 			snd_iprintf(buffer, "%3i:        : %s\n", minor,
394 				    snd_device_type_name(mptr->type));
395 	}
396 	mutex_unlock(&sound_mutex);
397 }
398 
399 int __init snd_minor_info_init(void)
400 {
401 	struct snd_info_entry *entry;
402 
403 	entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
404 	if (entry) {
405 		entry->c.text.read = snd_minor_info_read;
406 		if (snd_info_register(entry) < 0) {
407 			snd_info_free_entry(entry);
408 			entry = NULL;
409 		}
410 	}
411 	snd_minor_info_entry = entry;
412 	return 0;
413 }
414 
415 int __exit snd_minor_info_done(void)
416 {
417 	snd_info_free_entry(snd_minor_info_entry);
418 	return 0;
419 }
420 #endif /* CONFIG_PROC_FS */
421 
422 /*
423  *  INIT PART
424  */
425 
426 static int __init alsa_sound_init(void)
427 {
428 	snd_major = major;
429 	snd_ecards_limit = cards_limit;
430 	if (register_chrdev(major, "alsa", &snd_fops)) {
431 		snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
432 		return -EIO;
433 	}
434 	if (snd_info_init() < 0) {
435 		unregister_chrdev(major, "alsa");
436 		return -ENOMEM;
437 	}
438 	snd_info_minor_register();
439 #ifndef MODULE
440 	printk(KERN_INFO "Advanced Linux Sound Architecture Driver Version " CONFIG_SND_VERSION CONFIG_SND_DATE ".\n");
441 #endif
442 	return 0;
443 }
444 
445 static void __exit alsa_sound_exit(void)
446 {
447 	snd_info_minor_unregister();
448 	snd_info_done();
449 	if (unregister_chrdev(major, "alsa") != 0)
450 		snd_printk(KERN_ERR "unable to unregister major device number %d\n", major);
451 }
452 
453 module_init(alsa_sound_init)
454 module_exit(alsa_sound_exit)
455