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 21 static inline int init_oss_soundcore(void) { return 0; } 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 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 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 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 */ 173 174 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 */ 226 227 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 */ 253 254 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 return -EBUSY; 291 } 292 } 293 294 device_create(sound_class, dev, MKDEV(SOUND_MAJOR, s->unit_minor), 295 NULL, "%s", s->name+6); 296 return s->unit_minor; 297 298 fail: 299 kfree(s); 300 return r; 301 } 302 303 /* 304 * Remove a unit. Acquires locks as needed. The drivers MUST have 305 * completed the removal before their file operations become 306 * invalid. 307 */ 308 309 static void sound_remove_unit(struct sound_unit **list, int unit) 310 { 311 struct sound_unit *p; 312 313 spin_lock(&sound_loader_lock); 314 p = __sound_remove_unit(list, unit); 315 spin_unlock(&sound_loader_lock); 316 if (p) { 317 if (!preclaim_oss) 318 __unregister_chrdev(SOUND_MAJOR, p->unit_minor, 1, 319 p->name); 320 device_destroy(sound_class, MKDEV(SOUND_MAJOR, p->unit_minor)); 321 kfree(p); 322 } 323 } 324 325 /* 326 * Allocations 327 * 328 * 0 *16 Mixers 329 * 1 *8 Sequencers 330 * 2 *16 Midi 331 * 3 *16 DSP 332 * 4 *16 SunDSP 333 * 5 *16 DSP16 334 * 6 -- sndstat (obsolete) 335 * 7 *16 unused 336 * 8 -- alternate sequencer (see above) 337 * 9 *16 raw synthesizer access 338 * 10 *16 unused 339 * 11 *16 unused 340 * 12 *16 unused 341 * 13 *16 unused 342 * 14 *16 unused 343 * 15 *16 unused 344 */ 345 346 static struct sound_unit *chains[SOUND_STEP]; 347 348 /** 349 * register_sound_special_device - register a special sound node 350 * @fops: File operations for the driver 351 * @unit: Unit number to allocate 352 * @dev: device pointer 353 * 354 * Allocate a special sound device by minor number from the sound 355 * subsystem. 356 * 357 * Return: The allocated number is returned on success. On failure, 358 * a negative error code is returned. 359 */ 360 361 int register_sound_special_device(const struct file_operations *fops, int unit, 362 struct device *dev) 363 { 364 const int chain = unit % SOUND_STEP; 365 int max_unit = 256; 366 const char *name; 367 char _name[16]; 368 369 switch (chain) { 370 case 0: 371 name = "mixer"; 372 break; 373 case 1: 374 name = "sequencer"; 375 if (unit >= SOUND_STEP) 376 goto __unknown; 377 max_unit = unit + 1; 378 break; 379 case 2: 380 name = "midi"; 381 break; 382 case 3: 383 name = "dsp"; 384 break; 385 case 4: 386 name = "audio"; 387 break; 388 case 5: 389 name = "dspW"; 390 break; 391 case 8: 392 name = "sequencer2"; 393 if (unit >= SOUND_STEP) 394 goto __unknown; 395 max_unit = unit + 1; 396 break; 397 case 9: 398 name = "dmmidi"; 399 break; 400 case 10: 401 name = "dmfm"; 402 break; 403 case 12: 404 name = "adsp"; 405 break; 406 case 13: 407 name = "amidi"; 408 break; 409 case 14: 410 name = "admmidi"; 411 break; 412 default: 413 { 414 __unknown: 415 sprintf(_name, "unknown%d", chain); 416 if (unit >= SOUND_STEP) 417 strcat(_name, "-"); 418 name = _name; 419 } 420 break; 421 } 422 return sound_insert_unit(&chains[chain], fops, -1, unit, max_unit, 423 name, S_IRUSR | S_IWUSR, dev); 424 } 425 426 EXPORT_SYMBOL(register_sound_special_device); 427 428 int register_sound_special(const struct file_operations *fops, int unit) 429 { 430 return register_sound_special_device(fops, unit, NULL); 431 } 432 433 EXPORT_SYMBOL(register_sound_special); 434 435 /** 436 * register_sound_mixer - register a mixer device 437 * @fops: File operations for the driver 438 * @dev: Unit number to allocate 439 * 440 * Allocate a mixer device. Unit is the number of the mixer requested. 441 * Pass -1 to request the next free mixer unit. 442 * 443 * Return: On success, the allocated number is returned. On failure, 444 * a negative error code is returned. 445 */ 446 447 int register_sound_mixer(const struct file_operations *fops, int dev) 448 { 449 return sound_insert_unit(&chains[0], fops, dev, 0, 128, 450 "mixer", S_IRUSR | S_IWUSR, NULL); 451 } 452 453 EXPORT_SYMBOL(register_sound_mixer); 454 455 /** 456 * register_sound_midi - register a midi device 457 * @fops: File operations for the driver 458 * @dev: Unit number to allocate 459 * 460 * Allocate a midi device. Unit is the number of the midi device requested. 461 * Pass -1 to request the next free midi unit. 462 * 463 * Return: On success, the allocated number is returned. On failure, 464 * a negative error code is returned. 465 */ 466 467 int register_sound_midi(const struct file_operations *fops, int dev) 468 { 469 return sound_insert_unit(&chains[2], fops, dev, 2, 130, 470 "midi", S_IRUSR | S_IWUSR, NULL); 471 } 472 473 EXPORT_SYMBOL(register_sound_midi); 474 475 /* 476 * DSP's are registered as a triple. Register only one and cheat 477 * in open - see below. 478 */ 479 480 /** 481 * register_sound_dsp - register a DSP device 482 * @fops: File operations for the driver 483 * @dev: Unit number to allocate 484 * 485 * Allocate a DSP device. Unit is the number of the DSP requested. 486 * Pass -1 to request the next free DSP unit. 487 * 488 * This function allocates both the audio and dsp device entries together 489 * and will always allocate them as a matching pair - eg dsp3/audio3 490 * 491 * Return: On success, the allocated number is returned. On failure, 492 * a negative error code is returned. 493 */ 494 495 int register_sound_dsp(const struct file_operations *fops, int dev) 496 { 497 return sound_insert_unit(&chains[3], fops, dev, 3, 131, 498 "dsp", S_IWUSR | S_IRUSR, NULL); 499 } 500 501 EXPORT_SYMBOL(register_sound_dsp); 502 503 /** 504 * unregister_sound_special - unregister a special sound device 505 * @unit: unit number to allocate 506 * 507 * Release a sound device that was allocated with 508 * register_sound_special(). The unit passed is the return value from 509 * the register function. 510 */ 511 512 513 void unregister_sound_special(int unit) 514 { 515 sound_remove_unit(&chains[unit % SOUND_STEP], unit); 516 } 517 518 EXPORT_SYMBOL(unregister_sound_special); 519 520 /** 521 * unregister_sound_mixer - unregister a mixer 522 * @unit: unit number to allocate 523 * 524 * Release a sound device that was allocated with register_sound_mixer(). 525 * The unit passed is the return value from the register function. 526 */ 527 528 void unregister_sound_mixer(int unit) 529 { 530 sound_remove_unit(&chains[0], unit); 531 } 532 533 EXPORT_SYMBOL(unregister_sound_mixer); 534 535 /** 536 * unregister_sound_midi - unregister a midi device 537 * @unit: unit number to allocate 538 * 539 * Release a sound device that was allocated with register_sound_midi(). 540 * The unit passed is the return value from the register function. 541 */ 542 543 void unregister_sound_midi(int unit) 544 { 545 sound_remove_unit(&chains[2], unit); 546 } 547 548 EXPORT_SYMBOL(unregister_sound_midi); 549 550 /** 551 * unregister_sound_dsp - unregister a DSP device 552 * @unit: unit number to allocate 553 * 554 * Release a sound device that was allocated with register_sound_dsp(). 555 * The unit passed is the return value from the register function. 556 * 557 * Both of the allocated units are released together automatically. 558 */ 559 560 void unregister_sound_dsp(int unit) 561 { 562 sound_remove_unit(&chains[3], unit); 563 } 564 565 566 EXPORT_SYMBOL(unregister_sound_dsp); 567 568 static struct sound_unit *__look_for_unit(int chain, int unit) 569 { 570 struct sound_unit *s; 571 572 s=chains[chain]; 573 while(s && s->unit_minor <= unit) 574 { 575 if(s->unit_minor==unit) 576 return s; 577 s=s->next; 578 } 579 return NULL; 580 } 581 582 static int soundcore_open(struct inode *inode, struct file *file) 583 { 584 int chain; 585 int unit = iminor(inode); 586 struct sound_unit *s; 587 const struct file_operations *new_fops = NULL; 588 589 chain=unit&0x0F; 590 if(chain==4 || chain==5) /* dsp/audio/dsp16 */ 591 { 592 unit&=0xF0; 593 unit|=3; 594 chain=3; 595 } 596 597 spin_lock(&sound_loader_lock); 598 s = __look_for_unit(chain, unit); 599 if (s) 600 new_fops = fops_get(s->unit_fops); 601 if (preclaim_oss && !new_fops) { 602 spin_unlock(&sound_loader_lock); 603 604 /* 605 * Please, don't change this order or code. 606 * For ALSA slot means soundcard and OSS emulation code 607 * comes as add-on modules which aren't depend on 608 * ALSA toplevel modules for soundcards, thus we need 609 * load them at first. [Jaroslav Kysela <perex@jcu.cz>] 610 */ 611 request_module("sound-slot-%i", unit>>4); 612 request_module("sound-service-%i-%i", unit>>4, chain); 613 614 /* 615 * sound-slot/service-* module aliases are scheduled 616 * for removal in favor of the standard char-major-* 617 * module aliases. For the time being, generate both 618 * the legacy and standard module aliases to ease 619 * transition. 620 */ 621 if (request_module("char-major-%d-%d", SOUND_MAJOR, unit) > 0) 622 request_module("char-major-%d", SOUND_MAJOR); 623 624 spin_lock(&sound_loader_lock); 625 s = __look_for_unit(chain, unit); 626 if (s) 627 new_fops = fops_get(s->unit_fops); 628 } 629 spin_unlock(&sound_loader_lock); 630 if (new_fops) { 631 /* 632 * We rely upon the fact that we can't be unloaded while the 633 * subdriver is there. 634 */ 635 int err = 0; 636 replace_fops(file, new_fops); 637 638 if (file->f_op->open) 639 err = file->f_op->open(inode,file); 640 641 return err; 642 } 643 return -ENODEV; 644 } 645 646 MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR); 647 648 static void cleanup_oss_soundcore(void) 649 { 650 /* We have nothing to really do here - we know the lists must be 651 empty */ 652 unregister_chrdev(SOUND_MAJOR, "sound"); 653 } 654 655 static int __init init_oss_soundcore(void) 656 { 657 if (preclaim_oss && 658 register_chrdev(SOUND_MAJOR, "sound", &soundcore_fops) == -1) { 659 printk(KERN_ERR "soundcore: sound device already in use.\n"); 660 return -EBUSY; 661 } 662 663 return 0; 664 } 665 666 #endif /* CONFIG_SOUND_OSS_CORE */ 667