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->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. The allocated number is returned on success. On failure 356 * a negative error code is returned. 357 */ 358 359 int register_sound_special_device(const struct file_operations *fops, int unit, 360 struct device *dev) 361 { 362 const int chain = unit % SOUND_STEP; 363 int max_unit = 256; 364 const char *name; 365 char _name[16]; 366 367 switch (chain) { 368 case 0: 369 name = "mixer"; 370 break; 371 case 1: 372 name = "sequencer"; 373 if (unit >= SOUND_STEP) 374 goto __unknown; 375 max_unit = unit + 1; 376 break; 377 case 2: 378 name = "midi"; 379 break; 380 case 3: 381 name = "dsp"; 382 break; 383 case 4: 384 name = "audio"; 385 break; 386 case 5: 387 name = "dspW"; 388 break; 389 case 8: 390 name = "sequencer2"; 391 if (unit >= SOUND_STEP) 392 goto __unknown; 393 max_unit = unit + 1; 394 break; 395 case 9: 396 name = "dmmidi"; 397 break; 398 case 10: 399 name = "dmfm"; 400 break; 401 case 12: 402 name = "adsp"; 403 break; 404 case 13: 405 name = "amidi"; 406 break; 407 case 14: 408 name = "admmidi"; 409 break; 410 default: 411 { 412 __unknown: 413 sprintf(_name, "unknown%d", chain); 414 if (unit >= SOUND_STEP) 415 strcat(_name, "-"); 416 name = _name; 417 } 418 break; 419 } 420 return sound_insert_unit(&chains[chain], fops, -1, unit, max_unit, 421 name, S_IRUSR | S_IWUSR, dev); 422 } 423 424 EXPORT_SYMBOL(register_sound_special_device); 425 426 int register_sound_special(const struct file_operations *fops, int unit) 427 { 428 return register_sound_special_device(fops, unit, NULL); 429 } 430 431 EXPORT_SYMBOL(register_sound_special); 432 433 /** 434 * register_sound_mixer - register a mixer device 435 * @fops: File operations for the driver 436 * @dev: Unit number to allocate 437 * 438 * Allocate a mixer device. Unit is the number of the mixer requested. 439 * Pass -1 to request the next free mixer unit. On success the allocated 440 * number is returned, on failure a negative error code is returned. 441 */ 442 443 int register_sound_mixer(const struct file_operations *fops, int dev) 444 { 445 return sound_insert_unit(&chains[0], fops, dev, 0, 128, 446 "mixer", S_IRUSR | S_IWUSR, NULL); 447 } 448 449 EXPORT_SYMBOL(register_sound_mixer); 450 451 /** 452 * register_sound_midi - register a midi device 453 * @fops: File operations for the driver 454 * @dev: Unit number to allocate 455 * 456 * Allocate a midi device. Unit is the number of the midi device requested. 457 * Pass -1 to request the next free midi unit. On success the allocated 458 * number is returned, on failure a negative error code is returned. 459 */ 460 461 int register_sound_midi(const struct file_operations *fops, int dev) 462 { 463 return sound_insert_unit(&chains[2], fops, dev, 2, 130, 464 "midi", S_IRUSR | S_IWUSR, NULL); 465 } 466 467 EXPORT_SYMBOL(register_sound_midi); 468 469 /* 470 * DSP's are registered as a triple. Register only one and cheat 471 * in open - see below. 472 */ 473 474 /** 475 * register_sound_dsp - register a DSP device 476 * @fops: File operations for the driver 477 * @dev: Unit number to allocate 478 * 479 * Allocate a DSP device. Unit is the number of the DSP requested. 480 * Pass -1 to request the next free DSP unit. On success the allocated 481 * number is returned, on failure a negative error code is returned. 482 * 483 * This function allocates both the audio and dsp device entries together 484 * and will always allocate them as a matching pair - eg dsp3/audio3 485 */ 486 487 int register_sound_dsp(const struct file_operations *fops, int dev) 488 { 489 return sound_insert_unit(&chains[3], fops, dev, 3, 131, 490 "dsp", S_IWUSR | S_IRUSR, NULL); 491 } 492 493 EXPORT_SYMBOL(register_sound_dsp); 494 495 /** 496 * unregister_sound_special - unregister a special sound device 497 * @unit: unit number to allocate 498 * 499 * Release a sound device that was allocated with 500 * register_sound_special(). The unit passed is the return value from 501 * the register function. 502 */ 503 504 505 void unregister_sound_special(int unit) 506 { 507 sound_remove_unit(&chains[unit % SOUND_STEP], unit); 508 } 509 510 EXPORT_SYMBOL(unregister_sound_special); 511 512 /** 513 * unregister_sound_mixer - unregister a mixer 514 * @unit: unit number to allocate 515 * 516 * Release a sound device that was allocated with register_sound_mixer(). 517 * The unit passed is the return value from the register function. 518 */ 519 520 void unregister_sound_mixer(int unit) 521 { 522 sound_remove_unit(&chains[0], unit); 523 } 524 525 EXPORT_SYMBOL(unregister_sound_mixer); 526 527 /** 528 * unregister_sound_midi - unregister a midi device 529 * @unit: unit number to allocate 530 * 531 * Release a sound device that was allocated with register_sound_midi(). 532 * The unit passed is the return value from the register function. 533 */ 534 535 void unregister_sound_midi(int unit) 536 { 537 sound_remove_unit(&chains[2], unit); 538 } 539 540 EXPORT_SYMBOL(unregister_sound_midi); 541 542 /** 543 * unregister_sound_dsp - unregister a DSP device 544 * @unit: unit number to allocate 545 * 546 * Release a sound device that was allocated with register_sound_dsp(). 547 * The unit passed is the return value from the register function. 548 * 549 * Both of the allocated units are released together automatically. 550 */ 551 552 void unregister_sound_dsp(int unit) 553 { 554 sound_remove_unit(&chains[3], unit); 555 } 556 557 558 EXPORT_SYMBOL(unregister_sound_dsp); 559 560 static struct sound_unit *__look_for_unit(int chain, int unit) 561 { 562 struct sound_unit *s; 563 564 s=chains[chain]; 565 while(s && s->unit_minor <= unit) 566 { 567 if(s->unit_minor==unit) 568 return s; 569 s=s->next; 570 } 571 return NULL; 572 } 573 574 static int soundcore_open(struct inode *inode, struct file *file) 575 { 576 int chain; 577 int unit = iminor(inode); 578 struct sound_unit *s; 579 const struct file_operations *new_fops = NULL; 580 581 chain=unit&0x0F; 582 if(chain==4 || chain==5) /* dsp/audio/dsp16 */ 583 { 584 unit&=0xF0; 585 unit|=3; 586 chain=3; 587 } 588 589 spin_lock(&sound_loader_lock); 590 s = __look_for_unit(chain, unit); 591 if (s) 592 new_fops = fops_get(s->unit_fops); 593 if (preclaim_oss && !new_fops) { 594 spin_unlock(&sound_loader_lock); 595 596 /* 597 * Please, don't change this order or code. 598 * For ALSA slot means soundcard and OSS emulation code 599 * comes as add-on modules which aren't depend on 600 * ALSA toplevel modules for soundcards, thus we need 601 * load them at first. [Jaroslav Kysela <perex@jcu.cz>] 602 */ 603 request_module("sound-slot-%i", unit>>4); 604 request_module("sound-service-%i-%i", unit>>4, chain); 605 606 /* 607 * sound-slot/service-* module aliases are scheduled 608 * for removal in favor of the standard char-major-* 609 * module aliases. For the time being, generate both 610 * the legacy and standard module aliases to ease 611 * transition. 612 */ 613 if (request_module("char-major-%d-%d", SOUND_MAJOR, unit) > 0) 614 request_module("char-major-%d", SOUND_MAJOR); 615 616 spin_lock(&sound_loader_lock); 617 s = __look_for_unit(chain, unit); 618 if (s) 619 new_fops = fops_get(s->unit_fops); 620 } 621 if (new_fops) { 622 /* 623 * We rely upon the fact that we can't be unloaded while the 624 * subdriver is there, so if ->open() is successful we can 625 * safely drop the reference counter and if it is not we can 626 * revert to old ->f_op. Ugly, indeed, but that's the cost of 627 * switching ->f_op in the first place. 628 */ 629 int err = 0; 630 const struct file_operations *old_fops = file->f_op; 631 file->f_op = new_fops; 632 spin_unlock(&sound_loader_lock); 633 634 if (file->f_op->open) 635 err = file->f_op->open(inode,file); 636 637 if (err) { 638 fops_put(file->f_op); 639 file->f_op = fops_get(old_fops); 640 } 641 642 fops_put(old_fops); 643 return err; 644 } 645 spin_unlock(&sound_loader_lock); 646 return -ENODEV; 647 } 648 649 MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR); 650 651 static void cleanup_oss_soundcore(void) 652 { 653 /* We have nothing to really do here - we know the lists must be 654 empty */ 655 unregister_chrdev(SOUND_MAJOR, "sound"); 656 } 657 658 static int __init init_oss_soundcore(void) 659 { 660 if (preclaim_oss && 661 register_chrdev(SOUND_MAJOR, "sound", &soundcore_fops) == -1) { 662 printk(KERN_ERR "soundcore: sound device already in use.\n"); 663 return -EBUSY; 664 } 665 666 return 0; 667 } 668 669 #endif /* CONFIG_SOUND_OSS_CORE */ 670