1 /*
2 * Sound core. This file is composed of two parts. sound_class
3 * which is common to both OSS and ALSA and OSS sound core which
4 * is used OSS or emulation of it.
5 */
6
7 /*
8 * First, the common part.
9 */
10 #include <linux/module.h>
11 #include <linux/device.h>
12 #include <linux/err.h>
13 #include <linux/kdev_t.h>
14 #include <linux/major.h>
15 #include <sound/core.h>
16
17 #ifdef CONFIG_SOUND_OSS_CORE
18 static int __init init_oss_soundcore(void);
19 static void cleanup_oss_soundcore(void);
20 #else
init_oss_soundcore(void)21 static inline int init_oss_soundcore(void) { return 0; }
cleanup_oss_soundcore(void)22 static inline void cleanup_oss_soundcore(void) { }
23 #endif
24
25 struct class *sound_class;
26 EXPORT_SYMBOL(sound_class);
27
28 MODULE_DESCRIPTION("Core sound module");
29 MODULE_AUTHOR("Alan Cox");
30 MODULE_LICENSE("GPL");
31
sound_devnode(struct device * dev,umode_t * mode)32 static char *sound_devnode(struct device *dev, umode_t *mode)
33 {
34 if (MAJOR(dev->devt) == SOUND_MAJOR)
35 return NULL;
36 return kasprintf(GFP_KERNEL, "snd/%s", dev_name(dev));
37 }
38
init_soundcore(void)39 static int __init init_soundcore(void)
40 {
41 int rc;
42
43 rc = init_oss_soundcore();
44 if (rc)
45 return rc;
46
47 sound_class = class_create(THIS_MODULE, "sound");
48 if (IS_ERR(sound_class)) {
49 cleanup_oss_soundcore();
50 return PTR_ERR(sound_class);
51 }
52
53 sound_class->devnode = sound_devnode;
54
55 return 0;
56 }
57
cleanup_soundcore(void)58 static void __exit cleanup_soundcore(void)
59 {
60 cleanup_oss_soundcore();
61 class_destroy(sound_class);
62 }
63
64 subsys_initcall(init_soundcore);
65 module_exit(cleanup_soundcore);
66
67
68 #ifdef CONFIG_SOUND_OSS_CORE
69 /*
70 * OSS sound core handling. Breaks out sound functions to submodules
71 *
72 * Author: Alan Cox <alan@lxorguk.ukuu.org.uk>
73 *
74 * Fixes:
75 *
76 *
77 * This program is free software; you can redistribute it and/or
78 * modify it under the terms of the GNU General Public License
79 * as published by the Free Software Foundation; either version
80 * 2 of the License, or (at your option) any later version.
81 *
82 * --------------------
83 *
84 * Top level handler for the sound subsystem. Various devices can
85 * plug into this. The fact they don't all go via OSS doesn't mean
86 * they don't have to implement the OSS API. There is a lot of logic
87 * to keeping much of the OSS weight out of the code in a compatibility
88 * module, but it's up to the driver to rember to load it...
89 *
90 * The code provides a set of functions for registration of devices
91 * by type. This is done rather than providing a single call so that
92 * we can hide any future changes in the internals (eg when we go to
93 * 32bit dev_t) from the modules and their interface.
94 *
95 * Secondly we need to allocate the dsp, dsp16 and audio devices as
96 * one. Thus we misuse the chains a bit to simplify this.
97 *
98 * Thirdly to make it more fun and for 2.3.x and above we do all
99 * of this using fine grained locking.
100 *
101 * FIXME: we have to resolve modules and fine grained load/unload
102 * locking at some point in 2.3.x.
103 */
104
105 #include <linux/init.h>
106 #include <linux/slab.h>
107 #include <linux/types.h>
108 #include <linux/kernel.h>
109 #include <linux/sound.h>
110 #include <linux/kmod.h>
111
112 #define SOUND_STEP 16
113
114 struct sound_unit
115 {
116 int unit_minor;
117 const struct file_operations *unit_fops;
118 struct sound_unit *next;
119 char name[32];
120 };
121
122 #ifdef CONFIG_SOUND_MSNDCLAS
123 extern int msnd_classic_init(void);
124 #endif
125 #ifdef CONFIG_SOUND_MSNDPIN
126 extern int msnd_pinnacle_init(void);
127 #endif
128
129 /*
130 * By default, OSS sound_core claims full legacy minor range (0-255)
131 * of SOUND_MAJOR to trap open attempts to any sound minor and
132 * requests modules using custom sound-slot/service-* module aliases.
133 * The only benefit of doing this is allowing use of custom module
134 * aliases instead of the standard char-major-* ones. This behavior
135 * prevents alternative OSS implementation and is scheduled to be
136 * removed.
137 *
138 * CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss kernel
139 * parameter are added to allow distros and developers to try and
140 * switch to alternative implementations without needing to rebuild
141 * the kernel in the meantime. If preclaim_oss is non-zero, the
142 * kernel will behave the same as before. All SOUND_MAJOR minors are
143 * preclaimed and the custom module aliases along with standard chrdev
144 * ones are emitted if a missing device is opened. If preclaim_oss is
145 * zero, sound_core only grabs what's actually in use and for missing
146 * devices only the standard chrdev aliases are requested.
147 *
148 * All these clutters are scheduled to be removed along with
149 * sound-slot/service-* module aliases.
150 */
151 #ifdef CONFIG_SOUND_OSS_CORE_PRECLAIM
152 static int preclaim_oss = 1;
153 #else
154 static int preclaim_oss = 0;
155 #endif
156
157 module_param(preclaim_oss, int, 0444);
158
159 static int soundcore_open(struct inode *, struct file *);
160
161 static const struct file_operations soundcore_fops =
162 {
163 /* We must have an owner or the module locking fails */
164 .owner = THIS_MODULE,
165 .open = soundcore_open,
166 .llseek = noop_llseek,
167 };
168
169 /*
170 * Low level list operator. Scan the ordered list, find a hole and
171 * join into it. Called with the lock asserted
172 */
173
__sound_insert_unit(struct sound_unit * s,struct sound_unit ** list,const struct file_operations * fops,int index,int low,int top)174 static int __sound_insert_unit(struct sound_unit * s, struct sound_unit **list, const struct file_operations *fops, int index, int low, int top)
175 {
176 int n=low;
177
178 if (index < 0) { /* first free */
179
180 while (*list && (*list)->unit_minor<n)
181 list=&((*list)->next);
182
183 while(n<top)
184 {
185 /* Found a hole ? */
186 if(*list==NULL || (*list)->unit_minor>n)
187 break;
188 list=&((*list)->next);
189 n+=SOUND_STEP;
190 }
191
192 if(n>=top)
193 return -ENOENT;
194 } else {
195 n = low+(index*16);
196 while (*list) {
197 if ((*list)->unit_minor==n)
198 return -EBUSY;
199 if ((*list)->unit_minor>n)
200 break;
201 list=&((*list)->next);
202 }
203 }
204
205 /*
206 * Fill it in
207 */
208
209 s->unit_minor=n;
210 s->unit_fops=fops;
211
212 /*
213 * Link it
214 */
215
216 s->next=*list;
217 *list=s;
218
219
220 return n;
221 }
222
223 /*
224 * Remove a node from the chain. Called with the lock asserted
225 */
226
__sound_remove_unit(struct sound_unit ** list,int unit)227 static struct sound_unit *__sound_remove_unit(struct sound_unit **list, int unit)
228 {
229 while(*list)
230 {
231 struct sound_unit *p=*list;
232 if(p->unit_minor==unit)
233 {
234 *list=p->next;
235 return p;
236 }
237 list=&(p->next);
238 }
239 printk(KERN_ERR "Sound device %d went missing!\n", unit);
240 return NULL;
241 }
242
243 /*
244 * This lock guards the sound loader list.
245 */
246
247 static DEFINE_SPINLOCK(sound_loader_lock);
248
249 /*
250 * Allocate the controlling structure and add it to the sound driver
251 * list. Acquires locks as needed
252 */
253
sound_insert_unit(struct sound_unit ** list,const struct file_operations * fops,int index,int low,int top,const char * name,umode_t mode,struct device * dev)254 static int sound_insert_unit(struct sound_unit **list, const struct file_operations *fops, int index, int low, int top, const char *name, umode_t mode, struct device *dev)
255 {
256 struct sound_unit *s = kmalloc(sizeof(*s), GFP_KERNEL);
257 int r;
258
259 if (!s)
260 return -ENOMEM;
261
262 spin_lock(&sound_loader_lock);
263 retry:
264 r = __sound_insert_unit(s, list, fops, index, low, top);
265 spin_unlock(&sound_loader_lock);
266
267 if (r < 0)
268 goto fail;
269 else if (r < SOUND_STEP)
270 sprintf(s->name, "sound/%s", name);
271 else
272 sprintf(s->name, "sound/%s%d", name, r / SOUND_STEP);
273
274 if (!preclaim_oss) {
275 /*
276 * Something else might have grabbed the minor. If
277 * first free slot is requested, rescan with @low set
278 * to the next unit; otherwise, -EBUSY.
279 */
280 r = __register_chrdev(SOUND_MAJOR, s->unit_minor, 1, s->name,
281 &soundcore_fops);
282 if (r < 0) {
283 spin_lock(&sound_loader_lock);
284 __sound_remove_unit(list, s->unit_minor);
285 if (index < 0) {
286 low = s->unit_minor + SOUND_STEP;
287 goto retry;
288 }
289 spin_unlock(&sound_loader_lock);
290 r = -EBUSY;
291 goto fail;
292 }
293 }
294
295 device_create(sound_class, dev, MKDEV(SOUND_MAJOR, s->unit_minor),
296 NULL, "%s", s->name+6);
297 return s->unit_minor;
298
299 fail:
300 kfree(s);
301 return r;
302 }
303
304 /*
305 * Remove a unit. Acquires locks as needed. The drivers MUST have
306 * completed the removal before their file operations become
307 * invalid.
308 */
309
sound_remove_unit(struct sound_unit ** list,int unit)310 static void sound_remove_unit(struct sound_unit **list, int unit)
311 {
312 struct sound_unit *p;
313
314 spin_lock(&sound_loader_lock);
315 p = __sound_remove_unit(list, unit);
316 spin_unlock(&sound_loader_lock);
317 if (p) {
318 if (!preclaim_oss)
319 __unregister_chrdev(SOUND_MAJOR, p->unit_minor, 1,
320 p->name);
321 device_destroy(sound_class, MKDEV(SOUND_MAJOR, p->unit_minor));
322 kfree(p);
323 }
324 }
325
326 /*
327 * Allocations
328 *
329 * 0 *16 Mixers
330 * 1 *8 Sequencers
331 * 2 *16 Midi
332 * 3 *16 DSP
333 * 4 *16 SunDSP
334 * 5 *16 DSP16
335 * 6 -- sndstat (obsolete)
336 * 7 *16 unused
337 * 8 -- alternate sequencer (see above)
338 * 9 *16 raw synthesizer access
339 * 10 *16 unused
340 * 11 *16 unused
341 * 12 *16 unused
342 * 13 *16 unused
343 * 14 *16 unused
344 * 15 *16 unused
345 */
346
347 static struct sound_unit *chains[SOUND_STEP];
348
349 /**
350 * register_sound_special_device - register a special sound node
351 * @fops: File operations for the driver
352 * @unit: Unit number to allocate
353 * @dev: device pointer
354 *
355 * Allocate a special sound device by minor number from the sound
356 * subsystem.
357 *
358 * Return: The allocated number is returned on success. On failure,
359 * a negative error code is returned.
360 */
361
register_sound_special_device(const struct file_operations * fops,int unit,struct device * dev)362 int register_sound_special_device(const struct file_operations *fops, int unit,
363 struct device *dev)
364 {
365 const int chain = unit % SOUND_STEP;
366 int max_unit = 256;
367 const char *name;
368 char _name[16];
369
370 switch (chain) {
371 case 0:
372 name = "mixer";
373 break;
374 case 1:
375 name = "sequencer";
376 if (unit >= SOUND_STEP)
377 goto __unknown;
378 max_unit = unit + 1;
379 break;
380 case 2:
381 name = "midi";
382 break;
383 case 3:
384 name = "dsp";
385 break;
386 case 4:
387 name = "audio";
388 break;
389 case 5:
390 name = "dspW";
391 break;
392 case 8:
393 name = "sequencer2";
394 if (unit >= SOUND_STEP)
395 goto __unknown;
396 max_unit = unit + 1;
397 break;
398 case 9:
399 name = "dmmidi";
400 break;
401 case 10:
402 name = "dmfm";
403 break;
404 case 12:
405 name = "adsp";
406 break;
407 case 13:
408 name = "amidi";
409 break;
410 case 14:
411 name = "admmidi";
412 break;
413 default:
414 {
415 __unknown:
416 sprintf(_name, "unknown%d", chain);
417 if (unit >= SOUND_STEP)
418 strcat(_name, "-");
419 name = _name;
420 }
421 break;
422 }
423 return sound_insert_unit(&chains[chain], fops, -1, unit, max_unit,
424 name, S_IRUSR | S_IWUSR, dev);
425 }
426
427 EXPORT_SYMBOL(register_sound_special_device);
428
register_sound_special(const struct file_operations * fops,int unit)429 int register_sound_special(const struct file_operations *fops, int unit)
430 {
431 return register_sound_special_device(fops, unit, NULL);
432 }
433
434 EXPORT_SYMBOL(register_sound_special);
435
436 /**
437 * register_sound_mixer - register a mixer device
438 * @fops: File operations for the driver
439 * @dev: Unit number to allocate
440 *
441 * Allocate a mixer device. Unit is the number of the mixer requested.
442 * Pass -1 to request the next free mixer unit.
443 *
444 * Return: On success, the allocated number is returned. On failure,
445 * a negative error code is returned.
446 */
447
register_sound_mixer(const struct file_operations * fops,int dev)448 int register_sound_mixer(const struct file_operations *fops, int dev)
449 {
450 return sound_insert_unit(&chains[0], fops, dev, 0, 128,
451 "mixer", S_IRUSR | S_IWUSR, NULL);
452 }
453
454 EXPORT_SYMBOL(register_sound_mixer);
455
456 /**
457 * register_sound_midi - register a midi device
458 * @fops: File operations for the driver
459 * @dev: Unit number to allocate
460 *
461 * Allocate a midi device. Unit is the number of the midi device requested.
462 * Pass -1 to request the next free midi unit.
463 *
464 * Return: On success, the allocated number is returned. On failure,
465 * a negative error code is returned.
466 */
467
register_sound_midi(const struct file_operations * fops,int dev)468 int register_sound_midi(const struct file_operations *fops, int dev)
469 {
470 return sound_insert_unit(&chains[2], fops, dev, 2, 130,
471 "midi", S_IRUSR | S_IWUSR, NULL);
472 }
473
474 EXPORT_SYMBOL(register_sound_midi);
475
476 /*
477 * DSP's are registered as a triple. Register only one and cheat
478 * in open - see below.
479 */
480
481 /**
482 * register_sound_dsp - register a DSP device
483 * @fops: File operations for the driver
484 * @dev: Unit number to allocate
485 *
486 * Allocate a DSP device. Unit is the number of the DSP requested.
487 * Pass -1 to request the next free DSP unit.
488 *
489 * This function allocates both the audio and dsp device entries together
490 * and will always allocate them as a matching pair - eg dsp3/audio3
491 *
492 * Return: On success, the allocated number is returned. On failure,
493 * a negative error code is returned.
494 */
495
register_sound_dsp(const struct file_operations * fops,int dev)496 int register_sound_dsp(const struct file_operations *fops, int dev)
497 {
498 return sound_insert_unit(&chains[3], fops, dev, 3, 131,
499 "dsp", S_IWUSR | S_IRUSR, NULL);
500 }
501
502 EXPORT_SYMBOL(register_sound_dsp);
503
504 /**
505 * unregister_sound_special - unregister a special sound device
506 * @unit: unit number to allocate
507 *
508 * Release a sound device that was allocated with
509 * register_sound_special(). The unit passed is the return value from
510 * the register function.
511 */
512
513
unregister_sound_special(int unit)514 void unregister_sound_special(int unit)
515 {
516 sound_remove_unit(&chains[unit % SOUND_STEP], unit);
517 }
518
519 EXPORT_SYMBOL(unregister_sound_special);
520
521 /**
522 * unregister_sound_mixer - unregister a mixer
523 * @unit: unit number to allocate
524 *
525 * Release a sound device that was allocated with register_sound_mixer().
526 * The unit passed is the return value from the register function.
527 */
528
unregister_sound_mixer(int unit)529 void unregister_sound_mixer(int unit)
530 {
531 sound_remove_unit(&chains[0], unit);
532 }
533
534 EXPORT_SYMBOL(unregister_sound_mixer);
535
536 /**
537 * unregister_sound_midi - unregister a midi device
538 * @unit: unit number to allocate
539 *
540 * Release a sound device that was allocated with register_sound_midi().
541 * The unit passed is the return value from the register function.
542 */
543
unregister_sound_midi(int unit)544 void unregister_sound_midi(int unit)
545 {
546 sound_remove_unit(&chains[2], unit);
547 }
548
549 EXPORT_SYMBOL(unregister_sound_midi);
550
551 /**
552 * unregister_sound_dsp - unregister a DSP device
553 * @unit: unit number to allocate
554 *
555 * Release a sound device that was allocated with register_sound_dsp().
556 * The unit passed is the return value from the register function.
557 *
558 * Both of the allocated units are released together automatically.
559 */
560
unregister_sound_dsp(int unit)561 void unregister_sound_dsp(int unit)
562 {
563 sound_remove_unit(&chains[3], unit);
564 }
565
566
567 EXPORT_SYMBOL(unregister_sound_dsp);
568
__look_for_unit(int chain,int unit)569 static struct sound_unit *__look_for_unit(int chain, int unit)
570 {
571 struct sound_unit *s;
572
573 s=chains[chain];
574 while(s && s->unit_minor <= unit)
575 {
576 if(s->unit_minor==unit)
577 return s;
578 s=s->next;
579 }
580 return NULL;
581 }
582
soundcore_open(struct inode * inode,struct file * file)583 static int soundcore_open(struct inode *inode, struct file *file)
584 {
585 int chain;
586 int unit = iminor(inode);
587 struct sound_unit *s;
588 const struct file_operations *new_fops = NULL;
589
590 chain=unit&0x0F;
591 if(chain==4 || chain==5) /* dsp/audio/dsp16 */
592 {
593 unit&=0xF0;
594 unit|=3;
595 chain=3;
596 }
597
598 spin_lock(&sound_loader_lock);
599 s = __look_for_unit(chain, unit);
600 if (s)
601 new_fops = fops_get(s->unit_fops);
602 if (preclaim_oss && !new_fops) {
603 spin_unlock(&sound_loader_lock);
604
605 /*
606 * Please, don't change this order or code.
607 * For ALSA slot means soundcard and OSS emulation code
608 * comes as add-on modules which aren't depend on
609 * ALSA toplevel modules for soundcards, thus we need
610 * load them at first. [Jaroslav Kysela <perex@jcu.cz>]
611 */
612 request_module("sound-slot-%i", unit>>4);
613 request_module("sound-service-%i-%i", unit>>4, chain);
614
615 /*
616 * sound-slot/service-* module aliases are scheduled
617 * for removal in favor of the standard char-major-*
618 * module aliases. For the time being, generate both
619 * the legacy and standard module aliases to ease
620 * transition.
621 */
622 if (request_module("char-major-%d-%d", SOUND_MAJOR, unit) > 0)
623 request_module("char-major-%d", SOUND_MAJOR);
624
625 spin_lock(&sound_loader_lock);
626 s = __look_for_unit(chain, unit);
627 if (s)
628 new_fops = fops_get(s->unit_fops);
629 }
630 spin_unlock(&sound_loader_lock);
631 if (new_fops) {
632 /*
633 * We rely upon the fact that we can't be unloaded while the
634 * subdriver is there.
635 */
636 int err = 0;
637 replace_fops(file, new_fops);
638
639 if (file->f_op->open)
640 err = file->f_op->open(inode,file);
641
642 return err;
643 }
644 return -ENODEV;
645 }
646
647 MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR);
648
cleanup_oss_soundcore(void)649 static void cleanup_oss_soundcore(void)
650 {
651 /* We have nothing to really do here - we know the lists must be
652 empty */
653 unregister_chrdev(SOUND_MAJOR, "sound");
654 }
655
init_oss_soundcore(void)656 static int __init init_oss_soundcore(void)
657 {
658 if (preclaim_oss &&
659 register_chrdev(SOUND_MAJOR, "sound", &soundcore_fops) < 0) {
660 printk(KERN_ERR "soundcore: sound device already in use.\n");
661 return -EBUSY;
662 }
663
664 return 0;
665 }
666
667 #endif /* CONFIG_SOUND_OSS_CORE */
668