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/version.h>
31 #include <sound/control.h>
32 #include <sound/initval.h>
33 #include <linux/kmod.h>
34 #include <linux/mutex.h>
35
36 static int major = CONFIG_SND_MAJOR;
37 int snd_major;
38 EXPORT_SYMBOL(snd_major);
39
40 static int cards_limit = 1;
41
42 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
43 MODULE_DESCRIPTION("Advanced Linux Sound Architecture driver for soundcards.");
44 MODULE_LICENSE("GPL");
45 module_param(major, int, 0444);
46 MODULE_PARM_DESC(major, "Major # for sound driver.");
47 module_param(cards_limit, int, 0444);
48 MODULE_PARM_DESC(cards_limit, "Count of auto-loadable soundcards.");
49 MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR);
50
51 /* this one holds the actual max. card number currently available.
52 * as default, it's identical with cards_limit option. when more
53 * modules are loaded manually, this limit number increases, too.
54 */
55 int snd_ecards_limit;
56 EXPORT_SYMBOL(snd_ecards_limit);
57
58 static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
59 static DEFINE_MUTEX(sound_mutex);
60
61 #ifdef CONFIG_MODULES
62
63 /**
64 * snd_request_card - try to load the card module
65 * @card: the card number
66 *
67 * Tries to load the module "snd-card-X" for the given card number
68 * via request_module. Returns immediately if already loaded.
69 */
snd_request_card(int card)70 void snd_request_card(int card)
71 {
72 if (snd_card_locked(card))
73 return;
74 if (card < 0 || card >= cards_limit)
75 return;
76 request_module("snd-card-%i", card);
77 }
78
79 EXPORT_SYMBOL(snd_request_card);
80
snd_request_other(int minor)81 static void snd_request_other(int minor)
82 {
83 char *str;
84
85 switch (minor) {
86 case SNDRV_MINOR_SEQUENCER: str = "snd-seq"; break;
87 case SNDRV_MINOR_TIMER: str = "snd-timer"; break;
88 default: return;
89 }
90 request_module(str);
91 }
92
93 #endif /* modular kernel */
94
95 /**
96 * snd_lookup_minor_data - get user data of a registered device
97 * @minor: the minor number
98 * @type: device type (SNDRV_DEVICE_TYPE_XXX)
99 *
100 * Checks that a minor device with the specified type is registered, and returns
101 * its user data pointer.
102 *
103 * This function increments the reference counter of the card instance
104 * if an associated instance with the given minor number and type is found.
105 * The caller must call snd_card_unref() appropriately later.
106 */
snd_lookup_minor_data(unsigned int minor,int type)107 void *snd_lookup_minor_data(unsigned int minor, int type)
108 {
109 struct snd_minor *mreg;
110 void *private_data;
111
112 if (minor >= ARRAY_SIZE(snd_minors))
113 return NULL;
114 mutex_lock(&sound_mutex);
115 mreg = snd_minors[minor];
116 if (mreg && mreg->type == type) {
117 private_data = mreg->private_data;
118 if (private_data && mreg->card_ptr)
119 atomic_inc(&mreg->card_ptr->refcount);
120 } else
121 private_data = NULL;
122 mutex_unlock(&sound_mutex);
123 return private_data;
124 }
125
126 EXPORT_SYMBOL(snd_lookup_minor_data);
127
128 #ifdef CONFIG_MODULES
autoload_device(unsigned int minor)129 static struct snd_minor *autoload_device(unsigned int minor)
130 {
131 int dev;
132 mutex_unlock(&sound_mutex); /* release lock temporarily */
133 dev = SNDRV_MINOR_DEVICE(minor);
134 if (dev == SNDRV_MINOR_CONTROL) {
135 /* /dev/aloadC? */
136 int card = SNDRV_MINOR_CARD(minor);
137 if (snd_cards[card] == NULL)
138 snd_request_card(card);
139 } else if (dev == SNDRV_MINOR_GLOBAL) {
140 /* /dev/aloadSEQ */
141 snd_request_other(minor);
142 }
143 mutex_lock(&sound_mutex); /* reacuire lock */
144 return snd_minors[minor];
145 }
146 #else /* !CONFIG_MODULES */
147 #define autoload_device(minor) NULL
148 #endif /* CONFIG_MODULES */
149
snd_open(struct inode * inode,struct file * file)150 static int snd_open(struct inode *inode, struct file *file)
151 {
152 unsigned int minor = iminor(inode);
153 struct snd_minor *mptr = NULL;
154 const struct file_operations *old_fops;
155 int err = 0;
156
157 if (minor >= ARRAY_SIZE(snd_minors))
158 return -ENODEV;
159 mutex_lock(&sound_mutex);
160 mptr = snd_minors[minor];
161 if (mptr == NULL) {
162 mptr = autoload_device(minor);
163 if (!mptr) {
164 mutex_unlock(&sound_mutex);
165 return -ENODEV;
166 }
167 }
168 old_fops = file->f_op;
169 file->f_op = fops_get(mptr->f_ops);
170 if (file->f_op == NULL) {
171 file->f_op = old_fops;
172 err = -ENODEV;
173 }
174 mutex_unlock(&sound_mutex);
175 if (err < 0)
176 return err;
177
178 if (file->f_op->open) {
179 err = file->f_op->open(inode, file);
180 if (err) {
181 fops_put(file->f_op);
182 file->f_op = fops_get(old_fops);
183 }
184 }
185 fops_put(old_fops);
186 return err;
187 }
188
189 static const struct file_operations snd_fops =
190 {
191 .owner = THIS_MODULE,
192 .open = snd_open,
193 .llseek = noop_llseek,
194 };
195
196 #ifdef CONFIG_SND_DYNAMIC_MINORS
snd_find_free_minor(int type)197 static int snd_find_free_minor(int type)
198 {
199 int minor;
200
201 /* static minors for module auto loading */
202 if (type == SNDRV_DEVICE_TYPE_SEQUENCER)
203 return SNDRV_MINOR_SEQUENCER;
204 if (type == SNDRV_DEVICE_TYPE_TIMER)
205 return SNDRV_MINOR_TIMER;
206
207 for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
208 /* skip static minors still used for module auto loading */
209 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL)
210 continue;
211 if (minor == SNDRV_MINOR_SEQUENCER ||
212 minor == SNDRV_MINOR_TIMER)
213 continue;
214 if (!snd_minors[minor])
215 return minor;
216 }
217 return -EBUSY;
218 }
219 #else
snd_kernel_minor(int type,struct snd_card * card,int dev)220 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
221 {
222 int minor;
223
224 switch (type) {
225 case SNDRV_DEVICE_TYPE_SEQUENCER:
226 case SNDRV_DEVICE_TYPE_TIMER:
227 minor = type;
228 break;
229 case SNDRV_DEVICE_TYPE_CONTROL:
230 if (snd_BUG_ON(!card))
231 return -EINVAL;
232 minor = SNDRV_MINOR(card->number, type);
233 break;
234 case SNDRV_DEVICE_TYPE_HWDEP:
235 case SNDRV_DEVICE_TYPE_RAWMIDI:
236 case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
237 case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
238 case SNDRV_DEVICE_TYPE_COMPRESS:
239 if (snd_BUG_ON(!card))
240 return -EINVAL;
241 minor = SNDRV_MINOR(card->number, type + dev);
242 break;
243 default:
244 return -EINVAL;
245 }
246 if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
247 return -EINVAL;
248 return minor;
249 }
250 #endif
251
252 /**
253 * snd_register_device_for_dev - Register the ALSA device file for the card
254 * @type: the device type, SNDRV_DEVICE_TYPE_XXX
255 * @card: the card instance
256 * @dev: the device index
257 * @f_ops: the file operations
258 * @private_data: user pointer for f_ops->open()
259 * @name: the device file name
260 * @device: the &struct device to link this new device to
261 *
262 * Registers an ALSA device file for the given card.
263 * The operators have to be set in reg parameter.
264 *
265 * Returns zero if successful, or a negative error code on failure.
266 */
snd_register_device_for_dev(int type,struct snd_card * card,int dev,const struct file_operations * f_ops,void * private_data,const char * name,struct device * device)267 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
268 const struct file_operations *f_ops,
269 void *private_data,
270 const char *name, struct device *device)
271 {
272 int minor;
273 struct snd_minor *preg;
274
275 if (snd_BUG_ON(!name))
276 return -EINVAL;
277 preg = kmalloc(sizeof *preg, GFP_KERNEL);
278 if (preg == NULL)
279 return -ENOMEM;
280 preg->type = type;
281 preg->card = card ? card->number : -1;
282 preg->device = dev;
283 preg->f_ops = f_ops;
284 preg->private_data = private_data;
285 preg->card_ptr = card;
286 mutex_lock(&sound_mutex);
287 #ifdef CONFIG_SND_DYNAMIC_MINORS
288 minor = snd_find_free_minor(type);
289 #else
290 minor = snd_kernel_minor(type, card, dev);
291 if (minor >= 0 && snd_minors[minor])
292 minor = -EBUSY;
293 #endif
294 if (minor < 0) {
295 mutex_unlock(&sound_mutex);
296 kfree(preg);
297 return minor;
298 }
299 snd_minors[minor] = preg;
300 preg->dev = device_create(sound_class, device, MKDEV(major, minor),
301 private_data, "%s", name);
302 if (IS_ERR(preg->dev)) {
303 snd_minors[minor] = NULL;
304 mutex_unlock(&sound_mutex);
305 minor = PTR_ERR(preg->dev);
306 kfree(preg);
307 return minor;
308 }
309
310 mutex_unlock(&sound_mutex);
311 return 0;
312 }
313
314 EXPORT_SYMBOL(snd_register_device_for_dev);
315
316 /* find the matching minor record
317 * return the index of snd_minor, or -1 if not found
318 */
find_snd_minor(int type,struct snd_card * card,int dev)319 static int find_snd_minor(int type, struct snd_card *card, int dev)
320 {
321 int cardnum, minor;
322 struct snd_minor *mptr;
323
324 cardnum = card ? card->number : -1;
325 for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
326 if ((mptr = snd_minors[minor]) != NULL &&
327 mptr->type == type &&
328 mptr->card == cardnum &&
329 mptr->device == dev)
330 return minor;
331 return -1;
332 }
333
334 /**
335 * snd_unregister_device - unregister the device on the given card
336 * @type: the device type, SNDRV_DEVICE_TYPE_XXX
337 * @card: the card instance
338 * @dev: the device index
339 *
340 * Unregisters the device file already registered via
341 * snd_register_device().
342 *
343 * Returns zero if sucecessful, or a negative error code on failure
344 */
snd_unregister_device(int type,struct snd_card * card,int dev)345 int snd_unregister_device(int type, struct snd_card *card, int dev)
346 {
347 int minor;
348
349 mutex_lock(&sound_mutex);
350 minor = find_snd_minor(type, card, dev);
351 if (minor < 0) {
352 mutex_unlock(&sound_mutex);
353 return -EINVAL;
354 }
355
356 device_destroy(sound_class, MKDEV(major, minor));
357
358 kfree(snd_minors[minor]);
359 snd_minors[minor] = NULL;
360 mutex_unlock(&sound_mutex);
361 return 0;
362 }
363
364 EXPORT_SYMBOL(snd_unregister_device);
365
snd_add_device_sysfs_file(int type,struct snd_card * card,int dev,struct device_attribute * attr)366 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
367 struct device_attribute *attr)
368 {
369 int minor, ret = -EINVAL;
370 struct device *d;
371
372 mutex_lock(&sound_mutex);
373 minor = find_snd_minor(type, card, dev);
374 if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
375 ret = device_create_file(d, attr);
376 mutex_unlock(&sound_mutex);
377 return ret;
378
379 }
380
381 EXPORT_SYMBOL(snd_add_device_sysfs_file);
382
383 #ifdef CONFIG_PROC_FS
384 /*
385 * INFO PART
386 */
387
388 static struct snd_info_entry *snd_minor_info_entry;
389
snd_device_type_name(int type)390 static const char *snd_device_type_name(int type)
391 {
392 switch (type) {
393 case SNDRV_DEVICE_TYPE_CONTROL:
394 return "control";
395 case SNDRV_DEVICE_TYPE_HWDEP:
396 return "hardware dependent";
397 case SNDRV_DEVICE_TYPE_RAWMIDI:
398 return "raw midi";
399 case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
400 return "digital audio playback";
401 case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
402 return "digital audio capture";
403 case SNDRV_DEVICE_TYPE_SEQUENCER:
404 return "sequencer";
405 case SNDRV_DEVICE_TYPE_TIMER:
406 return "timer";
407 default:
408 return "?";
409 }
410 }
411
snd_minor_info_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)412 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
413 {
414 int minor;
415 struct snd_minor *mptr;
416
417 mutex_lock(&sound_mutex);
418 for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
419 if (!(mptr = snd_minors[minor]))
420 continue;
421 if (mptr->card >= 0) {
422 if (mptr->device >= 0)
423 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
424 minor, mptr->card, mptr->device,
425 snd_device_type_name(mptr->type));
426 else
427 snd_iprintf(buffer, "%3i: [%2i] : %s\n",
428 minor, mptr->card,
429 snd_device_type_name(mptr->type));
430 } else
431 snd_iprintf(buffer, "%3i: : %s\n", minor,
432 snd_device_type_name(mptr->type));
433 }
434 mutex_unlock(&sound_mutex);
435 }
436
snd_minor_info_init(void)437 int __init snd_minor_info_init(void)
438 {
439 struct snd_info_entry *entry;
440
441 entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
442 if (entry) {
443 entry->c.text.read = snd_minor_info_read;
444 if (snd_info_register(entry) < 0) {
445 snd_info_free_entry(entry);
446 entry = NULL;
447 }
448 }
449 snd_minor_info_entry = entry;
450 return 0;
451 }
452
snd_minor_info_done(void)453 int __exit snd_minor_info_done(void)
454 {
455 snd_info_free_entry(snd_minor_info_entry);
456 return 0;
457 }
458 #endif /* CONFIG_PROC_FS */
459
460 /*
461 * INIT PART
462 */
463
alsa_sound_init(void)464 static int __init alsa_sound_init(void)
465 {
466 snd_major = major;
467 snd_ecards_limit = cards_limit;
468 if (register_chrdev(major, "alsa", &snd_fops)) {
469 snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
470 return -EIO;
471 }
472 if (snd_info_init() < 0) {
473 unregister_chrdev(major, "alsa");
474 return -ENOMEM;
475 }
476 snd_info_minor_register();
477 #ifndef MODULE
478 printk(KERN_INFO "Advanced Linux Sound Architecture Driver Version " CONFIG_SND_VERSION CONFIG_SND_DATE ".\n");
479 #endif
480 return 0;
481 }
482
alsa_sound_exit(void)483 static void __exit alsa_sound_exit(void)
484 {
485 snd_info_minor_unregister();
486 snd_info_done();
487 unregister_chrdev(major, "alsa");
488 }
489
490 subsys_initcall(alsa_sound_init);
491 module_exit(alsa_sound_exit);
492