1 /*
2 * ALSA sequencer device management
3 * Copyright (c) 1999 by Takashi Iwai <tiwai@suse.de>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 *
20 *----------------------------------------------------------------
21 *
22 * This device handler separates the card driver module from sequencer
23 * stuff (sequencer core, synth drivers, etc), so that user can avoid
24 * to spend unnecessary resources e.g. if he needs only listening to
25 * MP3s.
26 *
27 * The card (or lowlevel) driver creates a sequencer device entry
28 * via snd_seq_device_new(). This is an entry pointer to communicate
29 * with the sequencer device "driver", which is involved with the
30 * actual part to communicate with the sequencer core.
31 * Each sequencer device entry has an id string and the corresponding
32 * driver with the same id is loaded when required. For example,
33 * lowlevel codes to access emu8000 chip on sbawe card are included in
34 * emu8000-synth module. To activate this module, the hardware
35 * resources like i/o port are passed via snd_seq_device argument.
36 *
37 */
38
39 #include <linux/init.h>
40 #include <sound/core.h>
41 #include <sound/info.h>
42 #include <sound/seq_device.h>
43 #include <sound/seq_kernel.h>
44 #include <sound/initval.h>
45 #include <linux/kmod.h>
46 #include <linux/slab.h>
47 #include <linux/mutex.h>
48
49 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
50 MODULE_DESCRIPTION("ALSA sequencer device management");
51 MODULE_LICENSE("GPL");
52
53 /* driver state */
54 #define DRIVER_EMPTY 0
55 #define DRIVER_LOADED (1<<0)
56 #define DRIVER_REQUESTED (1<<1)
57 #define DRIVER_LOCKED (1<<2)
58
59 struct ops_list {
60 char id[ID_LEN]; /* driver id */
61 int driver; /* driver state */
62 int used; /* reference counter */
63 int argsize; /* argument size */
64
65 /* operators */
66 struct snd_seq_dev_ops ops;
67
68 /* registred devices */
69 struct list_head dev_list; /* list of devices */
70 int num_devices; /* number of associated devices */
71 int num_init_devices; /* number of initialized devices */
72 struct mutex reg_mutex;
73
74 struct list_head list; /* next driver */
75 };
76
77
78 static LIST_HEAD(opslist);
79 static int num_ops;
80 static DEFINE_MUTEX(ops_mutex);
81 #ifdef CONFIG_PROC_FS
82 static struct snd_info_entry *info_entry;
83 #endif
84
85 /*
86 * prototypes
87 */
88 static int snd_seq_device_free(struct snd_seq_device *dev);
89 static int snd_seq_device_dev_free(struct snd_device *device);
90 static int snd_seq_device_dev_register(struct snd_device *device);
91 static int snd_seq_device_dev_disconnect(struct snd_device *device);
92
93 static int init_device(struct snd_seq_device *dev, struct ops_list *ops);
94 static int free_device(struct snd_seq_device *dev, struct ops_list *ops);
95 static struct ops_list *find_driver(char *id, int create_if_empty);
96 static struct ops_list *create_driver(char *id);
97 static void unlock_driver(struct ops_list *ops);
98 static void remove_drivers(void);
99
100 /*
101 * show all drivers and their status
102 */
103
104 #ifdef CONFIG_PROC_FS
snd_seq_device_info(struct snd_info_entry * entry,struct snd_info_buffer * buffer)105 static void snd_seq_device_info(struct snd_info_entry *entry,
106 struct snd_info_buffer *buffer)
107 {
108 struct ops_list *ops;
109
110 mutex_lock(&ops_mutex);
111 list_for_each_entry(ops, &opslist, list) {
112 snd_iprintf(buffer, "snd-%s%s%s%s,%d\n",
113 ops->id,
114 ops->driver & DRIVER_LOADED ? ",loaded" : (ops->driver == DRIVER_EMPTY ? ",empty" : ""),
115 ops->driver & DRIVER_REQUESTED ? ",requested" : "",
116 ops->driver & DRIVER_LOCKED ? ",locked" : "",
117 ops->num_devices);
118 }
119 mutex_unlock(&ops_mutex);
120 }
121 #endif
122
123 /*
124 * load all registered drivers (called from seq_clientmgr.c)
125 */
126
127 #ifdef CONFIG_MODULES
128 /* avoid auto-loading during module_init() */
129 static int snd_seq_in_init;
snd_seq_autoload_lock(void)130 void snd_seq_autoload_lock(void)
131 {
132 snd_seq_in_init++;
133 }
134
snd_seq_autoload_unlock(void)135 void snd_seq_autoload_unlock(void)
136 {
137 snd_seq_in_init--;
138 }
139 #endif
140
snd_seq_device_load_drivers(void)141 void snd_seq_device_load_drivers(void)
142 {
143 #ifdef CONFIG_MODULES
144 struct ops_list *ops;
145
146 /* Calling request_module during module_init()
147 * may cause blocking.
148 */
149 if (snd_seq_in_init)
150 return;
151
152 mutex_lock(&ops_mutex);
153 list_for_each_entry(ops, &opslist, list) {
154 if (! (ops->driver & DRIVER_LOADED) &&
155 ! (ops->driver & DRIVER_REQUESTED)) {
156 ops->used++;
157 mutex_unlock(&ops_mutex);
158 ops->driver |= DRIVER_REQUESTED;
159 request_module("snd-%s", ops->id);
160 mutex_lock(&ops_mutex);
161 ops->used--;
162 }
163 }
164 mutex_unlock(&ops_mutex);
165 #endif
166 }
167
168 /*
169 * register a sequencer device
170 * card = card info (NULL allowed)
171 * device = device number (if any)
172 * id = id of driver
173 * result = return pointer (NULL allowed if unnecessary)
174 */
snd_seq_device_new(struct snd_card * card,int device,char * id,int argsize,struct snd_seq_device ** result)175 int snd_seq_device_new(struct snd_card *card, int device, char *id, int argsize,
176 struct snd_seq_device **result)
177 {
178 struct snd_seq_device *dev;
179 struct ops_list *ops;
180 int err;
181 static struct snd_device_ops dops = {
182 .dev_free = snd_seq_device_dev_free,
183 .dev_register = snd_seq_device_dev_register,
184 .dev_disconnect = snd_seq_device_dev_disconnect,
185 };
186
187 if (result)
188 *result = NULL;
189
190 if (snd_BUG_ON(!id))
191 return -EINVAL;
192
193 ops = find_driver(id, 1);
194 if (ops == NULL)
195 return -ENOMEM;
196
197 dev = kzalloc(sizeof(*dev)*2 + argsize, GFP_KERNEL);
198 if (dev == NULL) {
199 unlock_driver(ops);
200 return -ENOMEM;
201 }
202
203 /* set up device info */
204 dev->card = card;
205 dev->device = device;
206 strlcpy(dev->id, id, sizeof(dev->id));
207 dev->argsize = argsize;
208 dev->status = SNDRV_SEQ_DEVICE_FREE;
209
210 /* add this device to the list */
211 mutex_lock(&ops->reg_mutex);
212 list_add_tail(&dev->list, &ops->dev_list);
213 ops->num_devices++;
214 mutex_unlock(&ops->reg_mutex);
215
216 unlock_driver(ops);
217
218 if ((err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops)) < 0) {
219 snd_seq_device_free(dev);
220 return err;
221 }
222
223 if (result)
224 *result = dev;
225
226 return 0;
227 }
228
229 /*
230 * free the existing device
231 */
snd_seq_device_free(struct snd_seq_device * dev)232 static int snd_seq_device_free(struct snd_seq_device *dev)
233 {
234 struct ops_list *ops;
235
236 if (snd_BUG_ON(!dev))
237 return -EINVAL;
238
239 ops = find_driver(dev->id, 0);
240 if (ops == NULL)
241 return -ENXIO;
242
243 /* remove the device from the list */
244 mutex_lock(&ops->reg_mutex);
245 list_del(&dev->list);
246 ops->num_devices--;
247 mutex_unlock(&ops->reg_mutex);
248
249 free_device(dev, ops);
250 if (dev->private_free)
251 dev->private_free(dev);
252 kfree(dev);
253
254 unlock_driver(ops);
255
256 return 0;
257 }
258
snd_seq_device_dev_free(struct snd_device * device)259 static int snd_seq_device_dev_free(struct snd_device *device)
260 {
261 struct snd_seq_device *dev = device->device_data;
262 return snd_seq_device_free(dev);
263 }
264
265 /*
266 * register the device
267 */
snd_seq_device_dev_register(struct snd_device * device)268 static int snd_seq_device_dev_register(struct snd_device *device)
269 {
270 struct snd_seq_device *dev = device->device_data;
271 struct ops_list *ops;
272
273 ops = find_driver(dev->id, 0);
274 if (ops == NULL)
275 return -ENOENT;
276
277 /* initialize this device if the corresponding driver was
278 * already loaded
279 */
280 if (ops->driver & DRIVER_LOADED)
281 init_device(dev, ops);
282
283 unlock_driver(ops);
284 return 0;
285 }
286
287 /*
288 * disconnect the device
289 */
snd_seq_device_dev_disconnect(struct snd_device * device)290 static int snd_seq_device_dev_disconnect(struct snd_device *device)
291 {
292 struct snd_seq_device *dev = device->device_data;
293 struct ops_list *ops;
294
295 ops = find_driver(dev->id, 0);
296 if (ops == NULL)
297 return -ENOENT;
298
299 free_device(dev, ops);
300
301 unlock_driver(ops);
302 return 0;
303 }
304
305 /*
306 * register device driver
307 * id = driver id
308 * entry = driver operators - duplicated to each instance
309 */
snd_seq_device_register_driver(char * id,struct snd_seq_dev_ops * entry,int argsize)310 int snd_seq_device_register_driver(char *id, struct snd_seq_dev_ops *entry,
311 int argsize)
312 {
313 struct ops_list *ops;
314 struct snd_seq_device *dev;
315
316 if (id == NULL || entry == NULL ||
317 entry->init_device == NULL || entry->free_device == NULL)
318 return -EINVAL;
319
320 snd_seq_autoload_lock();
321 ops = find_driver(id, 1);
322 if (ops == NULL) {
323 snd_seq_autoload_unlock();
324 return -ENOMEM;
325 }
326 if (ops->driver & DRIVER_LOADED) {
327 snd_printk(KERN_WARNING "driver_register: driver '%s' already exists\n", id);
328 unlock_driver(ops);
329 snd_seq_autoload_unlock();
330 return -EBUSY;
331 }
332
333 mutex_lock(&ops->reg_mutex);
334 /* copy driver operators */
335 ops->ops = *entry;
336 ops->driver |= DRIVER_LOADED;
337 ops->argsize = argsize;
338
339 /* initialize existing devices if necessary */
340 list_for_each_entry(dev, &ops->dev_list, list) {
341 init_device(dev, ops);
342 }
343 mutex_unlock(&ops->reg_mutex);
344
345 unlock_driver(ops);
346 snd_seq_autoload_unlock();
347
348 return 0;
349 }
350
351
352 /*
353 * create driver record
354 */
create_driver(char * id)355 static struct ops_list * create_driver(char *id)
356 {
357 struct ops_list *ops;
358
359 ops = kzalloc(sizeof(*ops), GFP_KERNEL);
360 if (ops == NULL)
361 return ops;
362
363 /* set up driver entry */
364 strlcpy(ops->id, id, sizeof(ops->id));
365 mutex_init(&ops->reg_mutex);
366 /*
367 * The ->reg_mutex locking rules are per-driver, so we create
368 * separate per-driver lock classes:
369 */
370 lockdep_set_class(&ops->reg_mutex, (struct lock_class_key *)id);
371
372 ops->driver = DRIVER_EMPTY;
373 INIT_LIST_HEAD(&ops->dev_list);
374 /* lock this instance */
375 ops->used = 1;
376
377 /* register driver entry */
378 mutex_lock(&ops_mutex);
379 list_add_tail(&ops->list, &opslist);
380 num_ops++;
381 mutex_unlock(&ops_mutex);
382
383 return ops;
384 }
385
386
387 /*
388 * unregister the specified driver
389 */
snd_seq_device_unregister_driver(char * id)390 int snd_seq_device_unregister_driver(char *id)
391 {
392 struct ops_list *ops;
393 struct snd_seq_device *dev;
394
395 ops = find_driver(id, 0);
396 if (ops == NULL)
397 return -ENXIO;
398 if (! (ops->driver & DRIVER_LOADED) ||
399 (ops->driver & DRIVER_LOCKED)) {
400 snd_printk(KERN_ERR "driver_unregister: cannot unload driver '%s': status=%x\n",
401 id, ops->driver);
402 unlock_driver(ops);
403 return -EBUSY;
404 }
405
406 /* close and release all devices associated with this driver */
407 mutex_lock(&ops->reg_mutex);
408 ops->driver |= DRIVER_LOCKED; /* do not remove this driver recursively */
409 list_for_each_entry(dev, &ops->dev_list, list) {
410 free_device(dev, ops);
411 }
412
413 ops->driver = 0;
414 if (ops->num_init_devices > 0)
415 snd_printk(KERN_ERR "free_driver: init_devices > 0!! (%d)\n",
416 ops->num_init_devices);
417 mutex_unlock(&ops->reg_mutex);
418
419 unlock_driver(ops);
420
421 /* remove empty driver entries */
422 remove_drivers();
423
424 return 0;
425 }
426
427
428 /*
429 * remove empty driver entries
430 */
remove_drivers(void)431 static void remove_drivers(void)
432 {
433 struct list_head *head;
434
435 mutex_lock(&ops_mutex);
436 head = opslist.next;
437 while (head != &opslist) {
438 struct ops_list *ops = list_entry(head, struct ops_list, list);
439 if (! (ops->driver & DRIVER_LOADED) &&
440 ops->used == 0 && ops->num_devices == 0) {
441 head = head->next;
442 list_del(&ops->list);
443 kfree(ops);
444 num_ops--;
445 } else
446 head = head->next;
447 }
448 mutex_unlock(&ops_mutex);
449 }
450
451 /*
452 * initialize the device - call init_device operator
453 */
init_device(struct snd_seq_device * dev,struct ops_list * ops)454 static int init_device(struct snd_seq_device *dev, struct ops_list *ops)
455 {
456 if (! (ops->driver & DRIVER_LOADED))
457 return 0; /* driver is not loaded yet */
458 if (dev->status != SNDRV_SEQ_DEVICE_FREE)
459 return 0; /* already initialized */
460 if (ops->argsize != dev->argsize) {
461 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n",
462 dev->name, ops->id, ops->argsize, dev->argsize);
463 return -EINVAL;
464 }
465 if (ops->ops.init_device(dev) >= 0) {
466 dev->status = SNDRV_SEQ_DEVICE_REGISTERED;
467 ops->num_init_devices++;
468 } else {
469 snd_printk(KERN_ERR "init_device failed: %s: %s\n",
470 dev->name, dev->id);
471 }
472
473 return 0;
474 }
475
476 /*
477 * release the device - call free_device operator
478 */
free_device(struct snd_seq_device * dev,struct ops_list * ops)479 static int free_device(struct snd_seq_device *dev, struct ops_list *ops)
480 {
481 int result;
482
483 if (! (ops->driver & DRIVER_LOADED))
484 return 0; /* driver is not loaded yet */
485 if (dev->status != SNDRV_SEQ_DEVICE_REGISTERED)
486 return 0; /* not registered */
487 if (ops->argsize != dev->argsize) {
488 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n",
489 dev->name, ops->id, ops->argsize, dev->argsize);
490 return -EINVAL;
491 }
492 if ((result = ops->ops.free_device(dev)) >= 0 || result == -ENXIO) {
493 dev->status = SNDRV_SEQ_DEVICE_FREE;
494 dev->driver_data = NULL;
495 ops->num_init_devices--;
496 } else {
497 snd_printk(KERN_ERR "free_device failed: %s: %s\n",
498 dev->name, dev->id);
499 }
500
501 return 0;
502 }
503
504 /*
505 * find the matching driver with given id
506 */
find_driver(char * id,int create_if_empty)507 static struct ops_list * find_driver(char *id, int create_if_empty)
508 {
509 struct ops_list *ops;
510
511 mutex_lock(&ops_mutex);
512 list_for_each_entry(ops, &opslist, list) {
513 if (strcmp(ops->id, id) == 0) {
514 ops->used++;
515 mutex_unlock(&ops_mutex);
516 return ops;
517 }
518 }
519 mutex_unlock(&ops_mutex);
520 if (create_if_empty)
521 return create_driver(id);
522 return NULL;
523 }
524
unlock_driver(struct ops_list * ops)525 static void unlock_driver(struct ops_list *ops)
526 {
527 mutex_lock(&ops_mutex);
528 ops->used--;
529 mutex_unlock(&ops_mutex);
530 }
531
532
533 /*
534 * module part
535 */
536
alsa_seq_device_init(void)537 static int __init alsa_seq_device_init(void)
538 {
539 #ifdef CONFIG_PROC_FS
540 info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers",
541 snd_seq_root);
542 if (info_entry == NULL)
543 return -ENOMEM;
544 info_entry->content = SNDRV_INFO_CONTENT_TEXT;
545 info_entry->c.text.read = snd_seq_device_info;
546 if (snd_info_register(info_entry) < 0) {
547 snd_info_free_entry(info_entry);
548 return -ENOMEM;
549 }
550 #endif
551 return 0;
552 }
553
alsa_seq_device_exit(void)554 static void __exit alsa_seq_device_exit(void)
555 {
556 remove_drivers();
557 #ifdef CONFIG_PROC_FS
558 snd_info_free_entry(info_entry);
559 #endif
560 if (num_ops)
561 snd_printk(KERN_ERR "drivers not released (%d)\n", num_ops);
562 }
563
564 module_init(alsa_seq_device_init)
565 module_exit(alsa_seq_device_exit)
566
567 EXPORT_SYMBOL(snd_seq_device_load_drivers);
568 EXPORT_SYMBOL(snd_seq_device_new);
569 EXPORT_SYMBOL(snd_seq_device_register_driver);
570 EXPORT_SYMBOL(snd_seq_device_unregister_driver);
571 EXPORT_SYMBOL(snd_seq_autoload_lock);
572 EXPORT_SYMBOL(snd_seq_autoload_unlock);
573