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1 | // SPDX-License-Identifier: GPL-2.0-or-later | |
2 | /* | |
3 | * Sound core. This file is composed of two parts. sound_class | |
4 | * which is common to both OSS and ALSA and OSS sound core which | |
5 | * is used OSS or emulation of it. | |
6 | */ | |
7 | ||
8 | /* | |
9 | * First, the common part. | |
10 | */ | |
11 | #include <linux/module.h> | |
12 | #include <linux/device.h> | |
13 | #include <linux/err.h> | |
14 | #include <linux/kdev_t.h> | |
15 | #include <linux/major.h> | |
16 | #include <sound/core.h> | |
17 | ||
18 | #ifdef CONFIG_SOUND_OSS_CORE | |
19 | static int __init init_oss_soundcore(void); | |
20 | static void cleanup_oss_soundcore(void); | |
21 | #else | |
22 | static inline int init_oss_soundcore(void) { return 0; } | |
23 | static inline void cleanup_oss_soundcore(void) { } | |
24 | #endif | |
25 | ||
26 | struct class *sound_class; | |
27 | EXPORT_SYMBOL(sound_class); | |
28 | ||
29 | MODULE_DESCRIPTION("Core sound module"); | |
30 | MODULE_AUTHOR("Alan Cox"); | |
31 | MODULE_LICENSE("GPL"); | |
32 | ||
33 | static char *sound_devnode(struct device *dev, umode_t *mode) | |
34 | { | |
35 | if (MAJOR(dev->devt) == SOUND_MAJOR) | |
36 | return NULL; | |
37 | return kasprintf(GFP_KERNEL, "snd/%s", dev_name(dev)); | |
38 | } | |
39 | ||
40 | static int __init init_soundcore(void) | |
41 | { | |
42 | int rc; | |
43 | ||
44 | rc = init_oss_soundcore(); | |
45 | if (rc) | |
46 | return rc; | |
47 | ||
48 | sound_class = class_create(THIS_MODULE, "sound"); | |
49 | if (IS_ERR(sound_class)) { | |
50 | cleanup_oss_soundcore(); | |
51 | return PTR_ERR(sound_class); | |
52 | } | |
53 | ||
54 | sound_class->devnode = sound_devnode; | |
55 | ||
56 | return 0; | |
57 | } | |
58 | ||
59 | static void __exit cleanup_soundcore(void) | |
60 | { | |
61 | cleanup_oss_soundcore(); | |
62 | class_destroy(sound_class); | |
63 | } | |
64 | ||
65 | subsys_initcall(init_soundcore); | |
66 | module_exit(cleanup_soundcore); | |
67 | ||
68 | ||
69 | #ifdef CONFIG_SOUND_OSS_CORE | |
70 | /* | |
71 | * OSS sound core handling. Breaks out sound functions to submodules | |
72 | * | |
73 | * Author: Alan Cox <alan@lxorguk.ukuu.org.uk> | |
74 | * | |
75 | * Fixes: | |
76 | * | |
77 | * -------------------- | |
78 | * | |
79 | * Top level handler for the sound subsystem. Various devices can | |
80 | * plug into this. The fact they don't all go via OSS doesn't mean | |
81 | * they don't have to implement the OSS API. There is a lot of logic | |
82 | * to keeping much of the OSS weight out of the code in a compatibility | |
83 | * module, but it's up to the driver to rember to load it... | |
84 | * | |
85 | * The code provides a set of functions for registration of devices | |
86 | * by type. This is done rather than providing a single call so that | |
87 | * we can hide any future changes in the internals (eg when we go to | |
88 | * 32bit dev_t) from the modules and their interface. | |
89 | * | |
90 | * Secondly we need to allocate the dsp, dsp16 and audio devices as | |
91 | * one. Thus we misuse the chains a bit to simplify this. | |
92 | * | |
93 | * Thirdly to make it more fun and for 2.3.x and above we do all | |
94 | * of this using fine grained locking. | |
95 | * | |
96 | * FIXME: we have to resolve modules and fine grained load/unload | |
97 | * locking at some point in 2.3.x. | |
98 | */ | |
99 | ||
100 | #include <linux/init.h> | |
101 | #include <linux/slab.h> | |
102 | #include <linux/types.h> | |
103 | #include <linux/kernel.h> | |
104 | #include <linux/sound.h> | |
105 | #include <linux/kmod.h> | |
106 | ||
107 | #define SOUND_STEP 16 | |
108 | ||
109 | struct sound_unit | |
110 | { | |
111 | int unit_minor; | |
112 | const struct file_operations *unit_fops; | |
113 | struct sound_unit *next; | |
114 | char name[32]; | |
115 | }; | |
116 | ||
117 | /* | |
118 | * By default, OSS sound_core claims full legacy minor range (0-255) | |
119 | * of SOUND_MAJOR to trap open attempts to any sound minor and | |
120 | * requests modules using custom sound-slot/service-* module aliases. | |
121 | * The only benefit of doing this is allowing use of custom module | |
122 | * aliases instead of the standard char-major-* ones. This behavior | |
123 | * prevents alternative OSS implementation and is scheduled to be | |
124 | * removed. | |
125 | * | |
126 | * CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss kernel | |
127 | * parameter are added to allow distros and developers to try and | |
128 | * switch to alternative implementations without needing to rebuild | |
129 | * the kernel in the meantime. If preclaim_oss is non-zero, the | |
130 | * kernel will behave the same as before. All SOUND_MAJOR minors are | |
131 | * preclaimed and the custom module aliases along with standard chrdev | |
132 | * ones are emitted if a missing device is opened. If preclaim_oss is | |
133 | * zero, sound_core only grabs what's actually in use and for missing | |
134 | * devices only the standard chrdev aliases are requested. | |
135 | * | |
136 | * All these clutters are scheduled to be removed along with | |
137 | * sound-slot/service-* module aliases. | |
138 | */ | |
139 | #ifdef CONFIG_SOUND_OSS_CORE_PRECLAIM | |
140 | static int preclaim_oss = 1; | |
141 | #else | |
142 | static int preclaim_oss = 0; | |
143 | #endif | |
144 | ||
145 | module_param(preclaim_oss, int, 0444); | |
146 | ||
147 | static int soundcore_open(struct inode *, struct file *); | |
148 | ||
149 | static const struct file_operations soundcore_fops = | |
150 | { | |
151 | /* We must have an owner or the module locking fails */ | |
152 | .owner = THIS_MODULE, | |
153 | .open = soundcore_open, | |
154 | .llseek = noop_llseek, | |
155 | }; | |
156 | ||
157 | /* | |
158 | * Low level list operator. Scan the ordered list, find a hole and | |
159 | * join into it. Called with the lock asserted | |
160 | */ | |
161 | ||
162 | static int __sound_insert_unit(struct sound_unit * s, struct sound_unit **list, const struct file_operations *fops, int index, int low, int top) | |
163 | { | |
164 | int n=low; | |
165 | ||
166 | if (index < 0) { /* first free */ | |
167 | ||
168 | while (*list && (*list)->unit_minor<n) | |
169 | list=&((*list)->next); | |
170 | ||
171 | while(n<top) | |
172 | { | |
173 | /* Found a hole ? */ | |
174 | if(*list==NULL || (*list)->unit_minor>n) | |
175 | break; | |
176 | list=&((*list)->next); | |
177 | n+=SOUND_STEP; | |
178 | } | |
179 | ||
180 | if(n>=top) | |
181 | return -ENOENT; | |
182 | } else { | |
183 | n = low+(index*16); | |
184 | while (*list) { | |
185 | if ((*list)->unit_minor==n) | |
186 | return -EBUSY; | |
187 | if ((*list)->unit_minor>n) | |
188 | break; | |
189 | list=&((*list)->next); | |
190 | } | |
191 | } | |
192 | ||
193 | /* | |
194 | * Fill it in | |
195 | */ | |
196 | ||
197 | s->unit_minor=n; | |
198 | s->unit_fops=fops; | |
199 | ||
200 | /* | |
201 | * Link it | |
202 | */ | |
203 | ||
204 | s->next=*list; | |
205 | *list=s; | |
206 | ||
207 | ||
208 | return n; | |
209 | } | |
210 | ||
211 | /* | |
212 | * Remove a node from the chain. Called with the lock asserted | |
213 | */ | |
214 | ||
215 | static struct sound_unit *__sound_remove_unit(struct sound_unit **list, int unit) | |
216 | { | |
217 | while(*list) | |
218 | { | |
219 | struct sound_unit *p=*list; | |
220 | if(p->unit_minor==unit) | |
221 | { | |
222 | *list=p->next; | |
223 | return p; | |
224 | } | |
225 | list=&(p->next); | |
226 | } | |
227 | printk(KERN_ERR "Sound device %d went missing!\n", unit); | |
228 | return NULL; | |
229 | } | |
230 | ||
231 | /* | |
232 | * This lock guards the sound loader list. | |
233 | */ | |
234 | ||
235 | static DEFINE_SPINLOCK(sound_loader_lock); | |
236 | ||
237 | /* | |
238 | * Allocate the controlling structure and add it to the sound driver | |
239 | * list. Acquires locks as needed | |
240 | */ | |
241 | ||
242 | 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) | |
243 | { | |
244 | struct sound_unit *s = kmalloc(sizeof(*s), GFP_KERNEL); | |
245 | int r; | |
246 | ||
247 | if (!s) | |
248 | return -ENOMEM; | |
249 | ||
250 | spin_lock(&sound_loader_lock); | |
251 | retry: | |
252 | r = __sound_insert_unit(s, list, fops, index, low, top); | |
253 | spin_unlock(&sound_loader_lock); | |
254 | ||
255 | if (r < 0) | |
256 | goto fail; | |
257 | else if (r < SOUND_STEP) | |
258 | sprintf(s->name, "sound/%s", name); | |
259 | else | |
260 | sprintf(s->name, "sound/%s%d", name, r / SOUND_STEP); | |
261 | ||
262 | if (!preclaim_oss) { | |
263 | /* | |
264 | * Something else might have grabbed the minor. If | |
265 | * first free slot is requested, rescan with @low set | |
266 | * to the next unit; otherwise, -EBUSY. | |
267 | */ | |
268 | r = __register_chrdev(SOUND_MAJOR, s->unit_minor, 1, s->name, | |
269 | &soundcore_fops); | |
270 | if (r < 0) { | |
271 | spin_lock(&sound_loader_lock); | |
272 | __sound_remove_unit(list, s->unit_minor); | |
273 | if (index < 0) { | |
274 | low = s->unit_minor + SOUND_STEP; | |
275 | goto retry; | |
276 | } | |
277 | spin_unlock(&sound_loader_lock); | |
278 | r = -EBUSY; | |
279 | goto fail; | |
280 | } | |
281 | } | |
282 | ||
283 | device_create(sound_class, dev, MKDEV(SOUND_MAJOR, s->unit_minor), | |
284 | NULL, "%s", s->name+6); | |
285 | return s->unit_minor; | |
286 | ||
287 | fail: | |
288 | kfree(s); | |
289 | return r; | |
290 | } | |
291 | ||
292 | /* | |
293 | * Remove a unit. Acquires locks as needed. The drivers MUST have | |
294 | * completed the removal before their file operations become | |
295 | * invalid. | |
296 | */ | |
297 | ||
298 | static void sound_remove_unit(struct sound_unit **list, int unit) | |
299 | { | |
300 | struct sound_unit *p; | |
301 | ||
302 | spin_lock(&sound_loader_lock); | |
303 | p = __sound_remove_unit(list, unit); | |
304 | spin_unlock(&sound_loader_lock); | |
305 | if (p) { | |
306 | if (!preclaim_oss) | |
307 | __unregister_chrdev(SOUND_MAJOR, p->unit_minor, 1, | |
308 | p->name); | |
309 | device_destroy(sound_class, MKDEV(SOUND_MAJOR, p->unit_minor)); | |
310 | kfree(p); | |
311 | } | |
312 | } | |
313 | ||
314 | /* | |
315 | * Allocations | |
316 | * | |
317 | * 0 *16 Mixers | |
318 | * 1 *8 Sequencers | |
319 | * 2 *16 Midi | |
320 | * 3 *16 DSP | |
321 | * 4 *16 SunDSP | |
322 | * 5 *16 DSP16 | |
323 | * 6 -- sndstat (obsolete) | |
324 | * 7 *16 unused | |
325 | * 8 -- alternate sequencer (see above) | |
326 | * 9 *16 raw synthesizer access | |
327 | * 10 *16 unused | |
328 | * 11 *16 unused | |
329 | * 12 *16 unused | |
330 | * 13 *16 unused | |
331 | * 14 *16 unused | |
332 | * 15 *16 unused | |
333 | */ | |
334 | ||
335 | static struct sound_unit *chains[SOUND_STEP]; | |
336 | ||
337 | /** | |
338 | * register_sound_special_device - register a special sound node | |
339 | * @fops: File operations for the driver | |
340 | * @unit: Unit number to allocate | |
341 | * @dev: device pointer | |
342 | * | |
343 | * Allocate a special sound device by minor number from the sound | |
344 | * subsystem. | |
345 | * | |
346 | * Return: The allocated number is returned on success. On failure, | |
347 | * a negative error code is returned. | |
348 | */ | |
349 | ||
350 | int register_sound_special_device(const struct file_operations *fops, int unit, | |
351 | struct device *dev) | |
352 | { | |
353 | const int chain = unit % SOUND_STEP; | |
354 | int max_unit = 256; | |
355 | const char *name; | |
356 | char _name[16]; | |
357 | ||
358 | switch (chain) { | |
359 | case 0: | |
360 | name = "mixer"; | |
361 | break; | |
362 | case 1: | |
363 | name = "sequencer"; | |
364 | if (unit >= SOUND_STEP) | |
365 | goto __unknown; | |
366 | max_unit = unit + 1; | |
367 | break; | |
368 | case 2: | |
369 | name = "midi"; | |
370 | break; | |
371 | case 3: | |
372 | name = "dsp"; | |
373 | break; | |
374 | case 4: | |
375 | name = "audio"; | |
376 | break; | |
377 | case 5: | |
378 | name = "dspW"; | |
379 | break; | |
380 | case 8: | |
381 | name = "sequencer2"; | |
382 | if (unit >= SOUND_STEP) | |
383 | goto __unknown; | |
384 | max_unit = unit + 1; | |
385 | break; | |
386 | case 9: | |
387 | name = "dmmidi"; | |
388 | break; | |
389 | case 10: | |
390 | name = "dmfm"; | |
391 | break; | |
392 | case 12: | |
393 | name = "adsp"; | |
394 | break; | |
395 | case 13: | |
396 | name = "amidi"; | |
397 | break; | |
398 | case 14: | |
399 | name = "admmidi"; | |
400 | break; | |
401 | default: | |
402 | { | |
403 | __unknown: | |
404 | sprintf(_name, "unknown%d", chain); | |
405 | if (unit >= SOUND_STEP) | |
406 | strcat(_name, "-"); | |
407 | name = _name; | |
408 | } | |
409 | break; | |
410 | } | |
411 | return sound_insert_unit(&chains[chain], fops, -1, unit, max_unit, | |
412 | name, 0600, dev); | |
413 | } | |
414 | ||
415 | EXPORT_SYMBOL(register_sound_special_device); | |
416 | ||
417 | int register_sound_special(const struct file_operations *fops, int unit) | |
418 | { | |
419 | return register_sound_special_device(fops, unit, NULL); | |
420 | } | |
421 | ||
422 | EXPORT_SYMBOL(register_sound_special); | |
423 | ||
424 | /** | |
425 | * register_sound_mixer - register a mixer device | |
426 | * @fops: File operations for the driver | |
427 | * @dev: Unit number to allocate | |
428 | * | |
429 | * Allocate a mixer device. Unit is the number of the mixer requested. | |
430 | * Pass -1 to request the next free mixer unit. | |
431 | * | |
432 | * Return: On success, the allocated number is returned. On failure, | |
433 | * a negative error code is returned. | |
434 | */ | |
435 | ||
436 | int register_sound_mixer(const struct file_operations *fops, int dev) | |
437 | { | |
438 | return sound_insert_unit(&chains[0], fops, dev, 0, 128, | |
439 | "mixer", 0600, NULL); | |
440 | } | |
441 | ||
442 | EXPORT_SYMBOL(register_sound_mixer); | |
443 | ||
444 | /* | |
445 | * DSP's are registered as a triple. Register only one and cheat | |
446 | * in open - see below. | |
447 | */ | |
448 | ||
449 | /** | |
450 | * register_sound_dsp - register a DSP device | |
451 | * @fops: File operations for the driver | |
452 | * @dev: Unit number to allocate | |
453 | * | |
454 | * Allocate a DSP device. Unit is the number of the DSP requested. | |
455 | * Pass -1 to request the next free DSP unit. | |
456 | * | |
457 | * This function allocates both the audio and dsp device entries together | |
458 | * and will always allocate them as a matching pair - eg dsp3/audio3 | |
459 | * | |
460 | * Return: On success, the allocated number is returned. On failure, | |
461 | * a negative error code is returned. | |
462 | */ | |
463 | ||
464 | int register_sound_dsp(const struct file_operations *fops, int dev) | |
465 | { | |
466 | return sound_insert_unit(&chains[3], fops, dev, 3, 131, | |
467 | "dsp", 0600, NULL); | |
468 | } | |
469 | ||
470 | EXPORT_SYMBOL(register_sound_dsp); | |
471 | ||
472 | /** | |
473 | * unregister_sound_special - unregister a special sound device | |
474 | * @unit: unit number to allocate | |
475 | * | |
476 | * Release a sound device that was allocated with | |
477 | * register_sound_special(). The unit passed is the return value from | |
478 | * the register function. | |
479 | */ | |
480 | ||
481 | ||
482 | void unregister_sound_special(int unit) | |
483 | { | |
484 | sound_remove_unit(&chains[unit % SOUND_STEP], unit); | |
485 | } | |
486 | ||
487 | EXPORT_SYMBOL(unregister_sound_special); | |
488 | ||
489 | /** | |
490 | * unregister_sound_mixer - unregister a mixer | |
491 | * @unit: unit number to allocate | |
492 | * | |
493 | * Release a sound device that was allocated with register_sound_mixer(). | |
494 | * The unit passed is the return value from the register function. | |
495 | */ | |
496 | ||
497 | void unregister_sound_mixer(int unit) | |
498 | { | |
499 | sound_remove_unit(&chains[0], unit); | |
500 | } | |
501 | ||
502 | EXPORT_SYMBOL(unregister_sound_mixer); | |
503 | ||
504 | /** | |
505 | * unregister_sound_dsp - unregister a DSP device | |
506 | * @unit: unit number to allocate | |
507 | * | |
508 | * Release a sound device that was allocated with register_sound_dsp(). | |
509 | * The unit passed is the return value from the register function. | |
510 | * | |
511 | * Both of the allocated units are released together automatically. | |
512 | */ | |
513 | ||
514 | void unregister_sound_dsp(int unit) | |
515 | { | |
516 | sound_remove_unit(&chains[3], unit); | |
517 | } | |
518 | ||
519 | ||
520 | EXPORT_SYMBOL(unregister_sound_dsp); | |
521 | ||
522 | static struct sound_unit *__look_for_unit(int chain, int unit) | |
523 | { | |
524 | struct sound_unit *s; | |
525 | ||
526 | s=chains[chain]; | |
527 | while(s && s->unit_minor <= unit) | |
528 | { | |
529 | if(s->unit_minor==unit) | |
530 | return s; | |
531 | s=s->next; | |
532 | } | |
533 | return NULL; | |
534 | } | |
535 | ||
536 | static int soundcore_open(struct inode *inode, struct file *file) | |
537 | { | |
538 | int chain; | |
539 | int unit = iminor(inode); | |
540 | struct sound_unit *s; | |
541 | const struct file_operations *new_fops = NULL; | |
542 | ||
543 | chain=unit&0x0F; | |
544 | if(chain==4 || chain==5) /* dsp/audio/dsp16 */ | |
545 | { | |
546 | unit&=0xF0; | |
547 | unit|=3; | |
548 | chain=3; | |
549 | } | |
550 | ||
551 | spin_lock(&sound_loader_lock); | |
552 | s = __look_for_unit(chain, unit); | |
553 | if (s) | |
554 | new_fops = fops_get(s->unit_fops); | |
555 | if (preclaim_oss && !new_fops) { | |
556 | spin_unlock(&sound_loader_lock); | |
557 | ||
558 | /* | |
559 | * Please, don't change this order or code. | |
560 | * For ALSA slot means soundcard and OSS emulation code | |
561 | * comes as add-on modules which aren't depend on | |
562 | * ALSA toplevel modules for soundcards, thus we need | |
563 | * load them at first. [Jaroslav Kysela <perex@jcu.cz>] | |
564 | */ | |
565 | request_module("sound-slot-%i", unit>>4); | |
566 | request_module("sound-service-%i-%i", unit>>4, chain); | |
567 | ||
568 | /* | |
569 | * sound-slot/service-* module aliases are scheduled | |
570 | * for removal in favor of the standard char-major-* | |
571 | * module aliases. For the time being, generate both | |
572 | * the legacy and standard module aliases to ease | |
573 | * transition. | |
574 | */ | |
575 | if (request_module("char-major-%d-%d", SOUND_MAJOR, unit) > 0) | |
576 | request_module("char-major-%d", SOUND_MAJOR); | |
577 | ||
578 | spin_lock(&sound_loader_lock); | |
579 | s = __look_for_unit(chain, unit); | |
580 | if (s) | |
581 | new_fops = fops_get(s->unit_fops); | |
582 | } | |
583 | spin_unlock(&sound_loader_lock); | |
584 | if (new_fops) { | |
585 | /* | |
586 | * We rely upon the fact that we can't be unloaded while the | |
587 | * subdriver is there. | |
588 | */ | |
589 | int err = 0; | |
590 | replace_fops(file, new_fops); | |
591 | ||
592 | if (file->f_op->open) | |
593 | err = file->f_op->open(inode,file); | |
594 | ||
595 | return err; | |
596 | } | |
597 | return -ENODEV; | |
598 | } | |
599 | ||
600 | MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR); | |
601 | ||
602 | static void cleanup_oss_soundcore(void) | |
603 | { | |
604 | /* We have nothing to really do here - we know the lists must be | |
605 | empty */ | |
606 | unregister_chrdev(SOUND_MAJOR, "sound"); | |
607 | } | |
608 | ||
609 | static int __init init_oss_soundcore(void) | |
610 | { | |
611 | if (preclaim_oss && | |
612 | register_chrdev(SOUND_MAJOR, "sound", &soundcore_fops) < 0) { | |
613 | printk(KERN_ERR "soundcore: sound device already in use.\n"); | |
614 | return -EBUSY; | |
615 | } | |
616 | ||
617 | return 0; | |
618 | } | |
619 | ||
620 | #endif /* CONFIG_SOUND_OSS_CORE */ |