2 * Advanced Linux Sound Architecture
3 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
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.
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.
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
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>
35 static int major = CONFIG_SND_MAJOR;
37 EXPORT_SYMBOL(snd_major);
39 static int cards_limit = 1;
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);
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.
55 EXPORT_SYMBOL(snd_ecards_limit);
57 static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
58 static DEFINE_MUTEX(sound_mutex);
63 * snd_request_card - try to load the card module
64 * @card: the card number
66 * Tries to load the module "snd-card-X" for the given card number
67 * via request_module. Returns immediately if already loaded.
69 void snd_request_card(int card)
71 if (snd_card_locked(card))
73 if (card < 0 || card >= cards_limit)
75 request_module("snd-card-%i", card);
77 EXPORT_SYMBOL(snd_request_card);
79 static void snd_request_other(int minor)
84 case SNDRV_MINOR_SEQUENCER: str = "snd-seq"; break;
85 case SNDRV_MINOR_TIMER: str = "snd-timer"; break;
91 #endif /* modular kernel */
94 * snd_lookup_minor_data - get user data of a registered device
95 * @minor: the minor number
96 * @type: device type (SNDRV_DEVICE_TYPE_XXX)
98 * Checks that a minor device with the specified type is registered, and returns
99 * its user data pointer.
101 * This function increments the reference counter of the card instance
102 * if an associated instance with the given minor number and type is found.
103 * The caller must call snd_card_unref() appropriately later.
105 * Return: The user data pointer if the specified device is found. %NULL
108 void *snd_lookup_minor_data(unsigned int minor, int type)
110 struct snd_minor *mreg;
113 if (minor >= ARRAY_SIZE(snd_minors))
115 mutex_lock(&sound_mutex);
116 mreg = snd_minors[minor];
117 if (mreg && mreg->type == type) {
118 private_data = mreg->private_data;
119 if (private_data && mreg->card_ptr)
120 get_device(&mreg->card_ptr->card_dev);
123 mutex_unlock(&sound_mutex);
126 EXPORT_SYMBOL(snd_lookup_minor_data);
128 #ifdef CONFIG_MODULES
129 static struct snd_minor *autoload_device(unsigned int minor)
132 mutex_unlock(&sound_mutex); /* release lock temporarily */
133 dev = SNDRV_MINOR_DEVICE(minor);
134 if (dev == SNDRV_MINOR_CONTROL) {
136 int card = SNDRV_MINOR_CARD(minor);
137 struct snd_card *ref = snd_card_ref(card);
139 snd_request_card(card);
142 } else if (dev == SNDRV_MINOR_GLOBAL) {
144 snd_request_other(minor);
146 mutex_lock(&sound_mutex); /* reacuire lock */
147 return snd_minors[minor];
149 #else /* !CONFIG_MODULES */
150 #define autoload_device(minor) NULL
151 #endif /* CONFIG_MODULES */
153 static int snd_open(struct inode *inode, struct file *file)
155 unsigned int minor = iminor(inode);
156 struct snd_minor *mptr = NULL;
157 const struct file_operations *new_fops;
160 if (minor >= ARRAY_SIZE(snd_minors))
162 mutex_lock(&sound_mutex);
163 mptr = snd_minors[minor];
165 mptr = autoload_device(minor);
167 mutex_unlock(&sound_mutex);
171 new_fops = fops_get(mptr->f_ops);
172 mutex_unlock(&sound_mutex);
175 replace_fops(file, new_fops);
177 if (file->f_op->open)
178 err = file->f_op->open(inode, file);
182 static const struct file_operations snd_fops =
184 .owner = THIS_MODULE,
186 .llseek = noop_llseek,
189 #ifdef CONFIG_SND_DYNAMIC_MINORS
190 static int snd_find_free_minor(int type, struct snd_card *card, int dev)
194 /* static minors for module auto loading */
195 if (type == SNDRV_DEVICE_TYPE_SEQUENCER)
196 return SNDRV_MINOR_SEQUENCER;
197 if (type == SNDRV_DEVICE_TYPE_TIMER)
198 return SNDRV_MINOR_TIMER;
200 for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
201 /* skip static minors still used for module auto loading */
202 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL)
204 if (minor == SNDRV_MINOR_SEQUENCER ||
205 minor == SNDRV_MINOR_TIMER)
207 if (!snd_minors[minor])
213 static int snd_find_free_minor(int type, struct snd_card *card, int dev)
218 case SNDRV_DEVICE_TYPE_SEQUENCER:
219 case SNDRV_DEVICE_TYPE_TIMER:
222 case SNDRV_DEVICE_TYPE_CONTROL:
223 if (snd_BUG_ON(!card))
225 minor = SNDRV_MINOR(card->number, type);
227 case SNDRV_DEVICE_TYPE_HWDEP:
228 case SNDRV_DEVICE_TYPE_RAWMIDI:
229 case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
230 case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
231 case SNDRV_DEVICE_TYPE_COMPRESS:
232 if (snd_BUG_ON(!card))
234 minor = SNDRV_MINOR(card->number, type + dev);
239 if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
241 if (snd_minors[minor])
248 * snd_register_device - Register the ALSA device file for the card
249 * @type: the device type, SNDRV_DEVICE_TYPE_XXX
250 * @card: the card instance
251 * @dev: the device index
252 * @f_ops: the file operations
253 * @private_data: user pointer for f_ops->open()
254 * @device: the device to register
256 * Registers an ALSA device file for the given card.
257 * The operators have to be set in reg parameter.
259 * Return: Zero if successful, or a negative error code on failure.
261 int snd_register_device(int type, struct snd_card *card, int dev,
262 const struct file_operations *f_ops,
263 void *private_data, struct device *device)
267 struct snd_minor *preg;
269 if (snd_BUG_ON(!device))
272 preg = kmalloc(sizeof *preg, GFP_KERNEL);
276 preg->card = card ? card->number : -1;
279 preg->private_data = private_data;
280 preg->card_ptr = card;
281 mutex_lock(&sound_mutex);
282 minor = snd_find_free_minor(type, card, dev);
289 device->devt = MKDEV(major, minor);
290 err = device_add(device);
294 snd_minors[minor] = preg;
296 mutex_unlock(&sound_mutex);
301 EXPORT_SYMBOL(snd_register_device);
304 * snd_unregister_device - unregister the device on the given card
305 * @dev: the device instance
307 * Unregisters the device file already registered via
308 * snd_register_device().
310 * Return: Zero if successful, or a negative error code on failure.
312 int snd_unregister_device(struct device *dev)
315 struct snd_minor *preg;
317 mutex_lock(&sound_mutex);
318 for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
319 preg = snd_minors[minor];
320 if (preg && preg->dev == dev) {
321 snd_minors[minor] = NULL;
327 mutex_unlock(&sound_mutex);
328 if (minor >= ARRAY_SIZE(snd_minors))
332 EXPORT_SYMBOL(snd_unregister_device);
334 #ifdef CONFIG_SND_PROC_FS
338 static const char *snd_device_type_name(int type)
341 case SNDRV_DEVICE_TYPE_CONTROL:
343 case SNDRV_DEVICE_TYPE_HWDEP:
344 return "hardware dependent";
345 case SNDRV_DEVICE_TYPE_RAWMIDI:
347 case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
348 return "digital audio playback";
349 case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
350 return "digital audio capture";
351 case SNDRV_DEVICE_TYPE_SEQUENCER:
353 case SNDRV_DEVICE_TYPE_TIMER:
360 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
363 struct snd_minor *mptr;
365 mutex_lock(&sound_mutex);
366 for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
367 if (!(mptr = snd_minors[minor]))
369 if (mptr->card >= 0) {
370 if (mptr->device >= 0)
371 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
372 minor, mptr->card, mptr->device,
373 snd_device_type_name(mptr->type));
375 snd_iprintf(buffer, "%3i: [%2i] : %s\n",
377 snd_device_type_name(mptr->type));
379 snd_iprintf(buffer, "%3i: : %s\n", minor,
380 snd_device_type_name(mptr->type));
382 mutex_unlock(&sound_mutex);
385 int __init snd_minor_info_init(void)
387 struct snd_info_entry *entry;
389 entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
392 entry->c.text.read = snd_minor_info_read;
393 return snd_info_register(entry); /* freed in error path */
395 #endif /* CONFIG_SND_PROC_FS */
401 static int __init alsa_sound_init(void)
404 snd_ecards_limit = cards_limit;
405 if (register_chrdev(major, "alsa", &snd_fops)) {
406 pr_err("ALSA core: unable to register native major device number %d\n", major);
409 if (snd_info_init() < 0) {
410 unregister_chrdev(major, "alsa");
414 pr_info("Advanced Linux Sound Architecture Driver Initialized.\n");
419 static void __exit alsa_sound_exit(void)
422 unregister_chrdev(major, "alsa");
425 subsys_initcall(alsa_sound_init);
426 module_exit(alsa_sound_exit);