[ACPI] merge acpi-2.6.12 branch into latest Linux 2.6.13-rc...
[linux-2.6] / sound / core / seq / seq_device.c
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 <sound/driver.h>
40 #include <linux/init.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
49 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
50 MODULE_DESCRIPTION("ALSA sequencer device management");
51 MODULE_LICENSE("GPL");
52
53 /*
54  * driver list
55  */
56 typedef struct ops_list ops_list_t;
57
58 /* driver state */
59 #define DRIVER_EMPTY            0
60 #define DRIVER_LOADED           (1<<0)
61 #define DRIVER_REQUESTED        (1<<1)
62 #define DRIVER_LOCKED           (1<<2)
63
64 struct ops_list {
65         char id[ID_LEN];        /* driver id */
66         int driver;             /* driver state */
67         int used;               /* reference counter */
68         int argsize;            /* argument size */
69
70         /* operators */
71         snd_seq_dev_ops_t ops;
72
73         /* registred devices */
74         struct list_head dev_list;      /* list of devices */
75         int num_devices;        /* number of associated devices */
76         int num_init_devices;   /* number of initialized devices */
77         struct semaphore reg_mutex;
78
79         struct list_head list;  /* next driver */
80 };
81
82
83 static LIST_HEAD(opslist);
84 static int num_ops;
85 static DECLARE_MUTEX(ops_mutex);
86 static snd_info_entry_t *info_entry = NULL;
87
88 /*
89  * prototypes
90  */
91 static int snd_seq_device_free(snd_seq_device_t *dev);
92 static int snd_seq_device_dev_free(snd_device_t *device);
93 static int snd_seq_device_dev_register(snd_device_t *device);
94 static int snd_seq_device_dev_disconnect(snd_device_t *device);
95 static int snd_seq_device_dev_unregister(snd_device_t *device);
96
97 static int init_device(snd_seq_device_t *dev, ops_list_t *ops);
98 static int free_device(snd_seq_device_t *dev, ops_list_t *ops);
99 static ops_list_t *find_driver(char *id, int create_if_empty);
100 static ops_list_t *create_driver(char *id);
101 static void unlock_driver(ops_list_t *ops);
102 static void remove_drivers(void);
103
104 /*
105  * show all drivers and their status
106  */
107
108 static void snd_seq_device_info(snd_info_entry_t *entry, snd_info_buffer_t * buffer)
109 {
110         struct list_head *head;
111
112         down(&ops_mutex);
113         list_for_each(head, &opslist) {
114                 ops_list_t *ops = list_entry(head, ops_list_t, list);
115                 snd_iprintf(buffer, "snd-%s%s%s%s,%d\n",
116                                 ops->id,
117                                 ops->driver & DRIVER_LOADED ? ",loaded" : (ops->driver == DRIVER_EMPTY ? ",empty" : ""),
118                                 ops->driver & DRIVER_REQUESTED ? ",requested" : "",
119                                 ops->driver & DRIVER_LOCKED ? ",locked" : "",
120                                 ops->num_devices);
121         }
122         up(&ops_mutex); 
123 }
124  
125 /*
126  * load all registered drivers (called from seq_clientmgr.c)
127  */
128
129 #ifdef CONFIG_KMOD
130 /* avoid auto-loading during module_init() */
131 static int snd_seq_in_init;
132 void snd_seq_autoload_lock(void)
133 {
134         snd_seq_in_init++;
135 }
136
137 void snd_seq_autoload_unlock(void)
138 {
139         snd_seq_in_init--;
140 }
141 #endif
142
143 void snd_seq_device_load_drivers(void)
144 {
145 #ifdef CONFIG_KMOD
146         struct list_head *head;
147
148         /* Calling request_module during module_init()
149          * may cause blocking.
150          */
151         if (snd_seq_in_init)
152                 return;
153
154         if (! current->fs->root)
155                 return;
156
157         down(&ops_mutex);
158         list_for_each(head, &opslist) {
159                 ops_list_t *ops = list_entry(head, ops_list_t, list);
160                 if (! (ops->driver & DRIVER_LOADED) &&
161                     ! (ops->driver & DRIVER_REQUESTED)) {
162                         ops->used++;
163                         up(&ops_mutex);
164                         ops->driver |= DRIVER_REQUESTED;
165                         request_module("snd-%s", ops->id);
166                         down(&ops_mutex);
167                         ops->used--;
168                 }
169         }
170         up(&ops_mutex);
171 #endif
172 }
173
174 /*
175  * register a sequencer device
176  * card = card info (NULL allowed)
177  * device = device number (if any)
178  * id = id of driver
179  * result = return pointer (NULL allowed if unnecessary)
180  */
181 int snd_seq_device_new(snd_card_t *card, int device, char *id, int argsize,
182                        snd_seq_device_t **result)
183 {
184         snd_seq_device_t *dev;
185         ops_list_t *ops;
186         int err;
187         static snd_device_ops_t dops = {
188                 .dev_free = snd_seq_device_dev_free,
189                 .dev_register = snd_seq_device_dev_register,
190                 .dev_disconnect = snd_seq_device_dev_disconnect,
191                 .dev_unregister = snd_seq_device_dev_unregister
192         };
193
194         if (result)
195                 *result = NULL;
196
197         snd_assert(id != NULL, return -EINVAL);
198
199         ops = find_driver(id, 1);
200         if (ops == NULL)
201                 return -ENOMEM;
202
203         dev = kcalloc(1, sizeof(*dev)*2 + argsize, GFP_KERNEL);
204         if (dev == NULL) {
205                 unlock_driver(ops);
206                 return -ENOMEM;
207         }
208
209         /* set up device info */
210         dev->card = card;
211         dev->device = device;
212         strlcpy(dev->id, id, sizeof(dev->id));
213         dev->argsize = argsize;
214         dev->status = SNDRV_SEQ_DEVICE_FREE;
215
216         /* add this device to the list */
217         down(&ops->reg_mutex);
218         list_add_tail(&dev->list, &ops->dev_list);
219         ops->num_devices++;
220         up(&ops->reg_mutex);
221
222         unlock_driver(ops);
223         
224         if ((err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops)) < 0) {
225                 snd_seq_device_free(dev);
226                 return err;
227         }
228         
229         if (result)
230                 *result = dev;
231
232         return 0;
233 }
234
235 /*
236  * free the existing device
237  */
238 static int snd_seq_device_free(snd_seq_device_t *dev)
239 {
240         ops_list_t *ops;
241
242         snd_assert(dev != NULL, return -EINVAL);
243
244         ops = find_driver(dev->id, 0);
245         if (ops == NULL)
246                 return -ENXIO;
247
248         /* remove the device from the list */
249         down(&ops->reg_mutex);
250         list_del(&dev->list);
251         ops->num_devices--;
252         up(&ops->reg_mutex);
253
254         free_device(dev, ops);
255         if (dev->private_free)
256                 dev->private_free(dev);
257         kfree(dev);
258
259         unlock_driver(ops);
260
261         return 0;
262 }
263
264 static int snd_seq_device_dev_free(snd_device_t *device)
265 {
266         snd_seq_device_t *dev = device->device_data;
267         return snd_seq_device_free(dev);
268 }
269
270 /*
271  * register the device
272  */
273 static int snd_seq_device_dev_register(snd_device_t *device)
274 {
275         snd_seq_device_t *dev = device->device_data;
276         ops_list_t *ops;
277
278         ops = find_driver(dev->id, 0);
279         if (ops == NULL)
280                 return -ENOENT;
281
282         /* initialize this device if the corresponding driver was
283          * already loaded
284          */
285         if (ops->driver & DRIVER_LOADED)
286                 init_device(dev, ops);
287
288         unlock_driver(ops);
289         return 0;
290 }
291
292 /*
293  * disconnect the device
294  */
295 static int snd_seq_device_dev_disconnect(snd_device_t *device)
296 {
297         snd_seq_device_t *dev = device->device_data;
298         ops_list_t *ops;
299
300         ops = find_driver(dev->id, 0);
301         if (ops == NULL)
302                 return -ENOENT;
303
304         free_device(dev, ops);
305
306         unlock_driver(ops);
307         return 0;
308 }
309
310 /*
311  * unregister the existing device
312  */
313 static int snd_seq_device_dev_unregister(snd_device_t *device)
314 {
315         snd_seq_device_t *dev = device->device_data;
316         return snd_seq_device_free(dev);
317 }
318
319 /*
320  * register device driver
321  * id = driver id
322  * entry = driver operators - duplicated to each instance
323  */
324 int snd_seq_device_register_driver(char *id, snd_seq_dev_ops_t *entry, int argsize)
325 {
326         struct list_head *head;
327         ops_list_t *ops;
328
329         if (id == NULL || entry == NULL ||
330             entry->init_device == NULL || entry->free_device == NULL)
331                 return -EINVAL;
332
333         snd_seq_autoload_lock();
334         ops = find_driver(id, 1);
335         if (ops == NULL) {
336                 snd_seq_autoload_unlock();
337                 return -ENOMEM;
338         }
339         if (ops->driver & DRIVER_LOADED) {
340                 snd_printk(KERN_WARNING "driver_register: driver '%s' already exists\n", id);
341                 unlock_driver(ops);
342                 snd_seq_autoload_unlock();
343                 return -EBUSY;
344         }
345
346         down(&ops->reg_mutex);
347         /* copy driver operators */
348         ops->ops = *entry;
349         ops->driver |= DRIVER_LOADED;
350         ops->argsize = argsize;
351
352         /* initialize existing devices if necessary */
353         list_for_each(head, &ops->dev_list) {
354                 snd_seq_device_t *dev = list_entry(head, snd_seq_device_t, list);
355                 init_device(dev, ops);
356         }
357         up(&ops->reg_mutex);
358
359         unlock_driver(ops);
360         snd_seq_autoload_unlock();
361
362         return 0;
363 }
364
365
366 /*
367  * create driver record
368  */
369 static ops_list_t * create_driver(char *id)
370 {
371         ops_list_t *ops;
372
373         ops = kmalloc(sizeof(*ops), GFP_KERNEL);
374         if (ops == NULL)
375                 return ops;
376         memset(ops, 0, sizeof(*ops));
377
378         /* set up driver entry */
379         strlcpy(ops->id, id, sizeof(ops->id));
380         init_MUTEX(&ops->reg_mutex);
381         ops->driver = DRIVER_EMPTY;
382         INIT_LIST_HEAD(&ops->dev_list);
383         /* lock this instance */
384         ops->used = 1;
385
386         /* register driver entry */
387         down(&ops_mutex);
388         list_add_tail(&ops->list, &opslist);
389         num_ops++;
390         up(&ops_mutex);
391
392         return ops;
393 }
394
395
396 /*
397  * unregister the specified driver
398  */
399 int snd_seq_device_unregister_driver(char *id)
400 {
401         struct list_head *head;
402         ops_list_t *ops;
403
404         ops = find_driver(id, 0);
405         if (ops == NULL)
406                 return -ENXIO;
407         if (! (ops->driver & DRIVER_LOADED) ||
408             (ops->driver & DRIVER_LOCKED)) {
409                 snd_printk(KERN_ERR "driver_unregister: cannot unload driver '%s': status=%x\n", id, ops->driver);
410                 unlock_driver(ops);
411                 return -EBUSY;
412         }
413
414         /* close and release all devices associated with this driver */
415         down(&ops->reg_mutex);
416         ops->driver |= DRIVER_LOCKED; /* do not remove this driver recursively */
417         list_for_each(head, &ops->dev_list) {
418                 snd_seq_device_t *dev = list_entry(head, snd_seq_device_t, list);
419                 free_device(dev, ops);
420         }
421
422         ops->driver = 0;
423         if (ops->num_init_devices > 0)
424                 snd_printk(KERN_ERR "free_driver: init_devices > 0!! (%d)\n", ops->num_init_devices);
425         up(&ops->reg_mutex);
426
427         unlock_driver(ops);
428
429         /* remove empty driver entries */
430         remove_drivers();
431
432         return 0;
433 }
434
435
436 /*
437  * remove empty driver entries
438  */
439 static void remove_drivers(void)
440 {
441         struct list_head *head;
442
443         down(&ops_mutex);
444         head = opslist.next;
445         while (head != &opslist) {
446                 ops_list_t *ops = list_entry(head, ops_list_t, list);
447                 if (! (ops->driver & DRIVER_LOADED) &&
448                     ops->used == 0 && ops->num_devices == 0) {
449                         head = head->next;
450                         list_del(&ops->list);
451                         kfree(ops);
452                         num_ops--;
453                 } else
454                         head = head->next;
455         }
456         up(&ops_mutex);
457 }
458
459 /*
460  * initialize the device - call init_device operator
461  */
462 static int init_device(snd_seq_device_t *dev, ops_list_t *ops)
463 {
464         if (! (ops->driver & DRIVER_LOADED))
465                 return 0; /* driver is not loaded yet */
466         if (dev->status != SNDRV_SEQ_DEVICE_FREE)
467                 return 0; /* already initialized */
468         if (ops->argsize != dev->argsize) {
469                 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n", dev->name, ops->id, ops->argsize, dev->argsize);
470                 return -EINVAL;
471         }
472         if (ops->ops.init_device(dev) >= 0) {
473                 dev->status = SNDRV_SEQ_DEVICE_REGISTERED;
474                 ops->num_init_devices++;
475         } else {
476                 snd_printk(KERN_ERR "init_device failed: %s: %s\n", dev->name, dev->id);
477         }
478
479         return 0;
480 }
481
482 /*
483  * release the device - call free_device operator
484  */
485 static int free_device(snd_seq_device_t *dev, ops_list_t *ops)
486 {
487         int result;
488
489         if (! (ops->driver & DRIVER_LOADED))
490                 return 0; /* driver is not loaded yet */
491         if (dev->status != SNDRV_SEQ_DEVICE_REGISTERED)
492                 return 0; /* not registered */
493         if (ops->argsize != dev->argsize) {
494                 snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n", dev->name, ops->id, ops->argsize, dev->argsize);
495                 return -EINVAL;
496         }
497         if ((result = ops->ops.free_device(dev)) >= 0 || result == -ENXIO) {
498                 dev->status = SNDRV_SEQ_DEVICE_FREE;
499                 dev->driver_data = NULL;
500                 ops->num_init_devices--;
501         } else {
502                 snd_printk(KERN_ERR "free_device failed: %s: %s\n", dev->name, dev->id);
503         }
504
505         return 0;
506 }
507
508 /*
509  * find the matching driver with given id
510  */
511 static ops_list_t * find_driver(char *id, int create_if_empty)
512 {
513         struct list_head *head;
514
515         down(&ops_mutex);
516         list_for_each(head, &opslist) {
517                 ops_list_t *ops = list_entry(head, ops_list_t, list);
518                 if (strcmp(ops->id, id) == 0) {
519                         ops->used++;
520                         up(&ops_mutex);
521                         return ops;
522                 }
523         }
524         up(&ops_mutex);
525         if (create_if_empty)
526                 return create_driver(id);
527         return NULL;
528 }
529
530 static void unlock_driver(ops_list_t *ops)
531 {
532         down(&ops_mutex);
533         ops->used--;
534         up(&ops_mutex);
535 }
536
537
538 /*
539  * module part
540  */
541
542 static int __init alsa_seq_device_init(void)
543 {
544         info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers", snd_seq_root);
545         if (info_entry == NULL)
546                 return -ENOMEM;
547         info_entry->content = SNDRV_INFO_CONTENT_TEXT;
548         info_entry->c.text.read_size = 2048;
549         info_entry->c.text.read = snd_seq_device_info;
550         if (snd_info_register(info_entry) < 0) {
551                 snd_info_free_entry(info_entry);
552                 return -ENOMEM;
553         }
554         return 0;
555 }
556
557 static void __exit alsa_seq_device_exit(void)
558 {
559         remove_drivers();
560         snd_info_unregister(info_entry);
561         if (num_ops)
562                 snd_printk(KERN_ERR "drivers not released (%d)\n", num_ops);
563 }
564
565 module_init(alsa_seq_device_init)
566 module_exit(alsa_seq_device_exit)
567
568 EXPORT_SYMBOL(snd_seq_device_load_drivers);
569 EXPORT_SYMBOL(snd_seq_device_new);
570 EXPORT_SYMBOL(snd_seq_device_register_driver);
571 EXPORT_SYMBOL(snd_seq_device_unregister_driver);
572 #ifdef CONFIG_KMOD
573 EXPORT_SYMBOL(snd_seq_autoload_lock);
574 EXPORT_SYMBOL(snd_seq_autoload_unlock);
575 #endif