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