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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/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>
34
35 static int major = CONFIG_SND_MAJOR;
36 int snd_major;
37 EXPORT_SYMBOL(snd_major);
38
39 static int cards_limit = 1;
40
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);
49
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.
53 */
54 int snd_ecards_limit;
55 EXPORT_SYMBOL(snd_ecards_limit);
56
57 static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
58 static DEFINE_MUTEX(sound_mutex);
59
60 #ifdef CONFIG_MODULES
61
62 /**
63 * snd_request_card - try to load the card module
64 * @card: the card number
65 *
66 * Tries to load the module "snd-card-X" for the given card number
67 * via request_module. Returns immediately if already loaded.
68 */
69 void snd_request_card(int card)
70 {
71 if (snd_card_locked(card))
72 return;
73 if (card < 0 || card >= cards_limit)
74 return;
75 request_module("snd-card-%i", card);
76 }
77
78 EXPORT_SYMBOL(snd_request_card);
79
80 static void snd_request_other(int minor)
81 {
82 char *str;
83
84 switch (minor) {
85 case SNDRV_MINOR_SEQUENCER: str = "snd-seq"; break;
86 case SNDRV_MINOR_TIMER: str = "snd-timer"; break;
87 default: return;
88 }
89 request_module(str);
90 }
91
92 #endif /* modular kernel */
93
94 /**
95 * snd_lookup_minor_data - get user data of a registered device
96 * @minor: the minor number
97 * @type: device type (SNDRV_DEVICE_TYPE_XXX)
98 *
99 * Checks that a minor device with the specified type is registered, and returns
100 * its user data pointer.
101 *
102 * This function increments the reference counter of the card instance
103 * if an associated instance with the given minor number and type is found.
104 * The caller must call snd_card_unref() appropriately later.
105 *
106 * Return: The user data pointer if the specified device is found. %NULL
107 * otherwise.
108 */
109 void *snd_lookup_minor_data(unsigned int minor, int type)
110 {
111 struct snd_minor *mreg;
112 void *private_data;
113
114 if (minor >= ARRAY_SIZE(snd_minors))
115 return NULL;
116 mutex_lock(&sound_mutex);
117 mreg = snd_minors[minor];
118 if (mreg && mreg->type == type) {
119 private_data = mreg->private_data;
120 if (private_data && mreg->card_ptr)
121 get_device(&mreg->card_ptr->card_dev);
122 } else
123 private_data = NULL;
124 mutex_unlock(&sound_mutex);
125 return private_data;
126 }
127
128 EXPORT_SYMBOL(snd_lookup_minor_data);
129
130 #ifdef CONFIG_MODULES
131 static struct snd_minor *autoload_device(unsigned int minor)
132 {
133 int dev;
134 mutex_unlock(&sound_mutex); /* release lock temporarily */
135 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 mutex_lock(&sound_mutex); /* reacuire lock */
146 return snd_minors[minor];
147 }
148 #else /* !CONFIG_MODULES */
149 #define autoload_device(minor) NULL
150 #endif /* CONFIG_MODULES */
151
152 static int snd_open(struct inode *inode, struct file *file)
153 {
154 unsigned int minor = iminor(inode);
155 struct snd_minor *mptr = NULL;
156 const struct file_operations *new_fops;
157 int err = 0;
158
159 if (minor >= ARRAY_SIZE(snd_minors))
160 return -ENODEV;
161 mutex_lock(&sound_mutex);
162 mptr = snd_minors[minor];
163 if (mptr == NULL) {
164 mptr = autoload_device(minor);
165 if (!mptr) {
166 mutex_unlock(&sound_mutex);
167 return -ENODEV;
168 }
169 }
170 new_fops = fops_get(mptr->f_ops);
171 mutex_unlock(&sound_mutex);
172 if (!new_fops)
173 return -ENODEV;
174 replace_fops(file, new_fops);
175
176 if (file->f_op->open)
177 err = file->f_op->open(inode, file);
178 return err;
179 }
180
181 static const struct file_operations snd_fops =
182 {
183 .owner = THIS_MODULE,
184 .open = snd_open,
185 .llseek = noop_llseek,
186 };
187
188 #ifdef CONFIG_SND_DYNAMIC_MINORS
189 static int snd_find_free_minor(int type, struct snd_card *card, int dev)
190 {
191 int minor;
192
193 /* static minors for module auto loading */
194 if (type == SNDRV_DEVICE_TYPE_SEQUENCER)
195 return SNDRV_MINOR_SEQUENCER;
196 if (type == SNDRV_DEVICE_TYPE_TIMER)
197 return SNDRV_MINOR_TIMER;
198
199 for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
200 /* skip static minors still used for module auto loading */
201 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL)
202 continue;
203 if (minor == SNDRV_MINOR_SEQUENCER ||
204 minor == SNDRV_MINOR_TIMER)
205 continue;
206 if (!snd_minors[minor])
207 return minor;
208 }
209 return -EBUSY;
210 }
211 #else
212 static int snd_find_free_minor(int type, struct snd_card *card, int dev)
213 {
214 int minor;
215
216 switch (type) {
217 case SNDRV_DEVICE_TYPE_SEQUENCER:
218 case SNDRV_DEVICE_TYPE_TIMER:
219 minor = type;
220 break;
221 case SNDRV_DEVICE_TYPE_CONTROL:
222 if (snd_BUG_ON(!card))
223 return -EINVAL;
224 minor = SNDRV_MINOR(card->number, type);
225 break;
226 case SNDRV_DEVICE_TYPE_HWDEP:
227 case SNDRV_DEVICE_TYPE_RAWMIDI:
228 case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
229 case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
230 case SNDRV_DEVICE_TYPE_COMPRESS:
231 if (snd_BUG_ON(!card))
232 return -EINVAL;
233 minor = SNDRV_MINOR(card->number, type + dev);
234 break;
235 default:
236 return -EINVAL;
237 }
238 if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
239 return -EINVAL;
240 if (snd_minors[minor])
241 return -EBUSY;
242 return minor;
243 }
244 #endif
245
246 /**
247 * snd_register_device - Register the ALSA device file for the card
248 * @type: the device type, SNDRV_DEVICE_TYPE_XXX
249 * @card: the card instance
250 * @dev: the device index
251 * @f_ops: the file operations
252 * @private_data: user pointer for f_ops->open()
253 * @device: the device to register
254 *
255 * Registers an ALSA device file for the given card.
256 * The operators have to be set in reg parameter.
257 *
258 * Return: Zero if successful, or a negative error code on failure.
259 */
260 int snd_register_device(int type, struct snd_card *card, int dev,
261 const struct file_operations *f_ops,
262 void *private_data, struct device *device)
263 {
264 int minor;
265 int err = 0;
266 struct snd_minor *preg;
267
268 if (snd_BUG_ON(!device))
269 return -EINVAL;
270
271 preg = kmalloc(sizeof *preg, GFP_KERNEL);
272 if (preg == NULL)
273 return -ENOMEM;
274 preg->type = type;
275 preg->card = card ? card->number : -1;
276 preg->device = dev;
277 preg->f_ops = f_ops;
278 preg->private_data = private_data;
279 preg->card_ptr = card;
280 mutex_lock(&sound_mutex);
281 minor = snd_find_free_minor(type, card, dev);
282 if (minor < 0) {
283 err = minor;
284 goto error;
285 }
286
287 preg->dev = device;
288 device->devt = MKDEV(major, minor);
289 err = device_add(device);
290 if (err < 0)
291 goto error;
292
293 snd_minors[minor] = preg;
294 error:
295 mutex_unlock(&sound_mutex);
296 if (err < 0)
297 kfree(preg);
298 return err;
299 }
300 EXPORT_SYMBOL(snd_register_device);
301
302 /**
303 * snd_unregister_device - unregister the device on the given card
304 * @dev: the device instance
305 *
306 * Unregisters the device file already registered via
307 * snd_register_device().
308 *
309 * Return: Zero if successful, or a negative error code on failure.
310 */
311 int snd_unregister_device(struct device *dev)
312 {
313 int minor;
314 struct snd_minor *preg;
315
316 mutex_lock(&sound_mutex);
317 for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
318 preg = snd_minors[minor];
319 if (preg && preg->dev == dev) {
320 snd_minors[minor] = NULL;
321 device_del(dev);
322 kfree(preg);
323 break;
324 }
325 }
326 mutex_unlock(&sound_mutex);
327 if (minor >= ARRAY_SIZE(snd_minors))
328 return -ENOENT;
329 return 0;
330 }
331 EXPORT_SYMBOL(snd_unregister_device);
332
333 #ifdef CONFIG_SND_PROC_FS
334 /*
335 * INFO PART
336 */
337 static const char *snd_device_type_name(int type)
338 {
339 switch (type) {
340 case SNDRV_DEVICE_TYPE_CONTROL:
341 return "control";
342 case SNDRV_DEVICE_TYPE_HWDEP:
343 return "hardware dependent";
344 case SNDRV_DEVICE_TYPE_RAWMIDI:
345 return "raw midi";
346 case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
347 return "digital audio playback";
348 case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
349 return "digital audio capture";
350 case SNDRV_DEVICE_TYPE_SEQUENCER:
351 return "sequencer";
352 case SNDRV_DEVICE_TYPE_TIMER:
353 return "timer";
354 default:
355 return "?";
356 }
357 }
358
359 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
360 {
361 int minor;
362 struct snd_minor *mptr;
363
364 mutex_lock(&sound_mutex);
365 for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
366 if (!(mptr = snd_minors[minor]))
367 continue;
368 if (mptr->card >= 0) {
369 if (mptr->device >= 0)
370 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
371 minor, mptr->card, mptr->device,
372 snd_device_type_name(mptr->type));
373 else
374 snd_iprintf(buffer, "%3i: [%2i] : %s\n",
375 minor, mptr->card,
376 snd_device_type_name(mptr->type));
377 } else
378 snd_iprintf(buffer, "%3i: : %s\n", minor,
379 snd_device_type_name(mptr->type));
380 }
381 mutex_unlock(&sound_mutex);
382 }
383
384 int __init snd_minor_info_init(void)
385 {
386 struct snd_info_entry *entry;
387
388 entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
389 if (!entry)
390 return -ENOMEM;
391 entry->c.text.read = snd_minor_info_read;
392 return snd_info_register(entry); /* freed in error path */
393 }
394 #endif /* CONFIG_SND_PROC_FS */
395
396 /*
397 * INIT PART
398 */
399
400 static int __init alsa_sound_init(void)
401 {
402 snd_major = major;
403 snd_ecards_limit = cards_limit;
404 if (register_chrdev(major, "alsa", &snd_fops)) {
405 pr_err("ALSA core: unable to register native major device number %d\n", major);
406 return -EIO;
407 }
408 if (snd_info_init() < 0) {
409 unregister_chrdev(major, "alsa");
410 return -ENOMEM;
411 }
412 #ifndef MODULE
413 pr_info("Advanced Linux Sound Architecture Driver Initialized.\n");
414 #endif
415 return 0;
416 }
417
418 static void __exit alsa_sound_exit(void)
419 {
420 snd_info_done();
421 unregister_chrdev(major, "alsa");
422 }
423
424 subsys_initcall(alsa_sound_init);
425 module_exit(alsa_sound_exit);