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, mode_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. Please take a look at 150 * feature-removal-schedule.txt for details. 151 */ 152 #ifdef CONFIG_SOUND_OSS_CORE_PRECLAIM 153 static int preclaim_oss = 1; 154 #else 155 static int preclaim_oss = 0; 156 #endif 157 158 module_param(preclaim_oss, int, 0444); 159 160 static int soundcore_open(struct inode *, struct file *); 161 162 static const struct file_operations soundcore_fops = 163 { 164 /* We must have an owner or the module locking fails */ 165 .owner = THIS_MODULE, 166 .open = soundcore_open, 167 .llseek = noop_llseek, 168 }; 169 170 /* 171 * Low level list operator. Scan the ordered list, find a hole and 172 * join into it. Called with the lock asserted 173 */ 174 175 static int __sound_insert_unit(struct sound_unit * s, struct sound_unit **list, const struct file_operations *fops, int index, int low, int top) 176 { 177 int n=low; 178 179 if (index < 0) { /* first free */ 180 181 while (*list && (*list)->unit_minor<n) 182 list=&((*list)->next); 183 184 while(n<top) 185 { 186 /* Found a hole ? */ 187 if(*list==NULL || (*list)->unit_minor>n) 188 break; 189 list=&((*list)->next); 190 n+=SOUND_STEP; 191 } 192 193 if(n>=top) 194 return -ENOENT; 195 } else { 196 n = low+(index*16); 197 while (*list) { 198 if ((*list)->unit_minor==n) 199 return -EBUSY; 200 if ((*list)->unit_minor>n) 201 break; 202 list=&((*list)->next); 203 } 204 } 205 206 /* 207 * Fill it in 208 */ 209 210 s->unit_minor=n; 211 s->unit_fops=fops; 212 213 /* 214 * Link it 215 */ 216 217 s->next=*list; 218 *list=s; 219 220 221 return n; 222 } 223 224 /* 225 * Remove a node from the chain. Called with the lock asserted 226 */ 227 228 static struct sound_unit *__sound_remove_unit(struct sound_unit **list, int unit) 229 { 230 while(*list) 231 { 232 struct sound_unit *p=*list; 233 if(p->unit_minor==unit) 234 { 235 *list=p->next; 236 return p; 237 } 238 list=&(p->next); 239 } 240 printk(KERN_ERR "Sound device %d went missing!\n", unit); 241 return NULL; 242 } 243 244 /* 245 * This lock guards the sound loader list. 246 */ 247 248 static DEFINE_SPINLOCK(sound_loader_lock); 249 250 /* 251 * Allocate the controlling structure and add it to the sound driver 252 * list. Acquires locks as needed 253 */ 254 255 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) 256 { 257 struct sound_unit *s = kmalloc(sizeof(*s), GFP_KERNEL); 258 int r; 259 260 if (!s) 261 return -ENOMEM; 262 263 spin_lock(&sound_loader_lock); 264 retry: 265 r = __sound_insert_unit(s, list, fops, index, low, top); 266 spin_unlock(&sound_loader_lock); 267 268 if (r < 0) 269 goto fail; 270 else if (r < SOUND_STEP) 271 sprintf(s->name, "sound/%s", name); 272 else 273 sprintf(s->name, "sound/%s%d", name, r / SOUND_STEP); 274 275 if (!preclaim_oss) { 276 /* 277 * Something else might have grabbed the minor. If 278 * first free slot is requested, rescan with @low set 279 * to the next unit; otherwise, -EBUSY. 280 */ 281 r = __register_chrdev(SOUND_MAJOR, s->unit_minor, 1, s->name, 282 &soundcore_fops); 283 if (r < 0) { 284 spin_lock(&sound_loader_lock); 285 __sound_remove_unit(list, s->unit_minor); 286 if (index < 0) { 287 low = s->unit_minor + SOUND_STEP; 288 goto retry; 289 } 290 spin_unlock(&sound_loader_lock); 291 return -EBUSY; 292 } 293 } 294 295 device_create(sound_class, dev, MKDEV(SOUND_MAJOR, s->unit_minor), 296 NULL, 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 */ 309 310 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. The allocated number is returned on success. On failure 357 * a negative error code is returned. 358 */ 359 360 int register_sound_special_device(const struct file_operations *fops, int unit, 361 struct device *dev) 362 { 363 const int chain = unit % SOUND_STEP; 364 int max_unit = 128 + chain; 365 const char *name; 366 char _name[16]; 367 368 switch (chain) { 369 case 0: 370 name = "mixer"; 371 break; 372 case 1: 373 name = "sequencer"; 374 if (unit >= SOUND_STEP) 375 goto __unknown; 376 max_unit = unit + 1; 377 break; 378 case 2: 379 name = "midi"; 380 break; 381 case 3: 382 name = "dsp"; 383 break; 384 case 4: 385 name = "audio"; 386 break; 387 case 5: 388 name = "dspW"; 389 break; 390 case 8: 391 name = "sequencer2"; 392 if (unit >= SOUND_STEP) 393 goto __unknown; 394 max_unit = unit + 1; 395 break; 396 case 9: 397 name = "dmmidi"; 398 break; 399 case 10: 400 name = "dmfm"; 401 break; 402 case 12: 403 name = "adsp"; 404 break; 405 case 13: 406 name = "amidi"; 407 break; 408 case 14: 409 name = "admmidi"; 410 break; 411 default: 412 { 413 __unknown: 414 sprintf(_name, "unknown%d", chain); 415 if (unit >= SOUND_STEP) 416 strcat(_name, "-"); 417 name = _name; 418 } 419 break; 420 } 421 return sound_insert_unit(&chains[chain], fops, -1, unit, max_unit, 422 name, S_IRUSR | S_IWUSR, dev); 423 } 424 425 EXPORT_SYMBOL(register_sound_special_device); 426 427 int register_sound_special(const struct file_operations *fops, int unit) 428 { 429 return register_sound_special_device(fops, unit, NULL); 430 } 431 432 EXPORT_SYMBOL(register_sound_special); 433 434 /** 435 * register_sound_mixer - register a mixer device 436 * @fops: File operations for the driver 437 * @dev: Unit number to allocate 438 * 439 * Allocate a mixer device. Unit is the number of the mixer requested. 440 * Pass -1 to request the next free mixer unit. On success the allocated 441 * number is returned, on failure a negative error code is returned. 442 */ 443 444 int register_sound_mixer(const struct file_operations *fops, int dev) 445 { 446 return sound_insert_unit(&chains[0], fops, dev, 0, 128, 447 "mixer", S_IRUSR | S_IWUSR, NULL); 448 } 449 450 EXPORT_SYMBOL(register_sound_mixer); 451 452 /** 453 * register_sound_midi - register a midi device 454 * @fops: File operations for the driver 455 * @dev: Unit number to allocate 456 * 457 * Allocate a midi device. Unit is the number of the midi device requested. 458 * Pass -1 to request the next free midi unit. On success the allocated 459 * number is returned, on failure a negative error code is returned. 460 */ 461 462 int register_sound_midi(const struct file_operations *fops, int dev) 463 { 464 return sound_insert_unit(&chains[2], fops, dev, 2, 130, 465 "midi", S_IRUSR | S_IWUSR, NULL); 466 } 467 468 EXPORT_SYMBOL(register_sound_midi); 469 470 /* 471 * DSP's are registered as a triple. Register only one and cheat 472 * in open - see below. 473 */ 474 475 /** 476 * register_sound_dsp - register a DSP device 477 * @fops: File operations for the driver 478 * @dev: Unit number to allocate 479 * 480 * Allocate a DSP device. Unit is the number of the DSP requested. 481 * Pass -1 to request the next free DSP unit. On success the allocated 482 * number is returned, on failure a negative error code is returned. 483 * 484 * This function allocates both the audio and dsp device entries together 485 * and will always allocate them as a matching pair - eg dsp3/audio3 486 */ 487 488 int register_sound_dsp(const struct file_operations *fops, int dev) 489 { 490 return sound_insert_unit(&chains[3], fops, dev, 3, 131, 491 "dsp", S_IWUSR | S_IRUSR, NULL); 492 } 493 494 EXPORT_SYMBOL(register_sound_dsp); 495 496 /** 497 * unregister_sound_special - unregister a special sound device 498 * @unit: unit number to allocate 499 * 500 * Release a sound device that was allocated with 501 * register_sound_special(). The unit passed is the return value from 502 * the register function. 503 */ 504 505 506 void unregister_sound_special(int unit) 507 { 508 sound_remove_unit(&chains[unit % SOUND_STEP], unit); 509 } 510 511 EXPORT_SYMBOL(unregister_sound_special); 512 513 /** 514 * unregister_sound_mixer - unregister a mixer 515 * @unit: unit number to allocate 516 * 517 * Release a sound device that was allocated with register_sound_mixer(). 518 * The unit passed is the return value from the register function. 519 */ 520 521 void unregister_sound_mixer(int unit) 522 { 523 sound_remove_unit(&chains[0], unit); 524 } 525 526 EXPORT_SYMBOL(unregister_sound_mixer); 527 528 /** 529 * unregister_sound_midi - unregister a midi device 530 * @unit: unit number to allocate 531 * 532 * Release a sound device that was allocated with register_sound_midi(). 533 * The unit passed is the return value from the register function. 534 */ 535 536 void unregister_sound_midi(int unit) 537 { 538 sound_remove_unit(&chains[2], unit); 539 } 540 541 EXPORT_SYMBOL(unregister_sound_midi); 542 543 /** 544 * unregister_sound_dsp - unregister a DSP device 545 * @unit: unit number to allocate 546 * 547 * Release a sound device that was allocated with register_sound_dsp(). 548 * The unit passed is the return value from the register function. 549 * 550 * Both of the allocated units are released together automatically. 551 */ 552 553 void unregister_sound_dsp(int unit) 554 { 555 sound_remove_unit(&chains[3], unit); 556 } 557 558 559 EXPORT_SYMBOL(unregister_sound_dsp); 560 561 static struct sound_unit *__look_for_unit(int chain, int unit) 562 { 563 struct sound_unit *s; 564 565 s=chains[chain]; 566 while(s && s->unit_minor <= unit) 567 { 568 if(s->unit_minor==unit) 569 return s; 570 s=s->next; 571 } 572 return NULL; 573 } 574 575 static int soundcore_open(struct inode *inode, struct file *file) 576 { 577 int chain; 578 int unit = iminor(inode); 579 struct sound_unit *s; 580 const struct file_operations *new_fops = NULL; 581 582 chain=unit&0x0F; 583 if(chain==4 || chain==5) /* dsp/audio/dsp16 */ 584 { 585 unit&=0xF0; 586 unit|=3; 587 chain=3; 588 } 589 590 spin_lock(&sound_loader_lock); 591 s = __look_for_unit(chain, unit); 592 if (s) 593 new_fops = fops_get(s->unit_fops); 594 if (preclaim_oss && !new_fops) { 595 spin_unlock(&sound_loader_lock); 596 597 /* 598 * Please, don't change this order or code. 599 * For ALSA slot means soundcard and OSS emulation code 600 * comes as add-on modules which aren't depend on 601 * ALSA toplevel modules for soundcards, thus we need 602 * load them at first. [Jaroslav Kysela <perex@jcu.cz>] 603 */ 604 request_module("sound-slot-%i", unit>>4); 605 request_module("sound-service-%i-%i", unit>>4, chain); 606 607 /* 608 * sound-slot/service-* module aliases are scheduled 609 * for removal in favor of the standard char-major-* 610 * module aliases. For the time being, generate both 611 * the legacy and standard module aliases to ease 612 * transition. 613 */ 614 if (request_module("char-major-%d-%d", SOUND_MAJOR, unit) > 0) 615 request_module("char-major-%d", SOUND_MAJOR); 616 617 spin_lock(&sound_loader_lock); 618 s = __look_for_unit(chain, unit); 619 if (s) 620 new_fops = fops_get(s->unit_fops); 621 } 622 if (new_fops) { 623 /* 624 * We rely upon the fact that we can't be unloaded while the 625 * subdriver is there, so if ->open() is successful we can 626 * safely drop the reference counter and if it is not we can 627 * revert to old ->f_op. Ugly, indeed, but that's the cost of 628 * switching ->f_op in the first place. 629 */ 630 int err = 0; 631 const struct file_operations *old_fops = file->f_op; 632 file->f_op = new_fops; 633 spin_unlock(&sound_loader_lock); 634 635 if (file->f_op->open) 636 err = file->f_op->open(inode,file); 637 638 if (err) { 639 fops_put(file->f_op); 640 file->f_op = fops_get(old_fops); 641 } 642 643 fops_put(old_fops); 644 return err; 645 } 646 spin_unlock(&sound_loader_lock); 647 return -ENODEV; 648 } 649 650 MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR); 651 652 static void cleanup_oss_soundcore(void) 653 { 654 /* We have nothing to really do here - we know the lists must be 655 empty */ 656 unregister_chrdev(SOUND_MAJOR, "sound"); 657 } 658 659 static int __init init_oss_soundcore(void) 660 { 661 if (preclaim_oss && 662 register_chrdev(SOUND_MAJOR, "sound", &soundcore_fops) == -1) { 663 printk(KERN_ERR "soundcore: sound device already in use.\n"); 664 return -EBUSY; 665 } 666 667 return 0; 668 } 669 670 #endif /* CONFIG_SOUND_OSS_CORE */ 671