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 /* 123 * By default, OSS sound_core claims full legacy minor range (0-255) 124 * of SOUND_MAJOR to trap open attempts to any sound minor and 125 * requests modules using custom sound-slot/service-* module aliases. 126 * The only benefit of doing this is allowing use of custom module 127 * aliases instead of the standard char-major-* ones. This behavior 128 * prevents alternative OSS implementation and is scheduled to be 129 * removed. 130 * 131 * CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss kernel 132 * parameter are added to allow distros and developers to try and 133 * switch to alternative implementations without needing to rebuild 134 * the kernel in the meantime. If preclaim_oss is non-zero, the 135 * kernel will behave the same as before. All SOUND_MAJOR minors are 136 * preclaimed and the custom module aliases along with standard chrdev 137 * ones are emitted if a missing device is opened. If preclaim_oss is 138 * zero, sound_core only grabs what's actually in use and for missing 139 * devices only the standard chrdev aliases are requested. 140 * 141 * All these clutters are scheduled to be removed along with 142 * sound-slot/service-* module aliases. 143 */ 144 #ifdef CONFIG_SOUND_OSS_CORE_PRECLAIM 145 static int preclaim_oss = 1; 146 #else 147 static int preclaim_oss = 0; 148 #endif 149 150 module_param(preclaim_oss, int, 0444); 151 152 static int soundcore_open(struct inode *, struct file *); 153 154 static const struct file_operations soundcore_fops = 155 { 156 /* We must have an owner or the module locking fails */ 157 .owner = THIS_MODULE, 158 .open = soundcore_open, 159 .llseek = noop_llseek, 160 }; 161 162 /* 163 * Low level list operator. Scan the ordered list, find a hole and 164 * join into it. Called with the lock asserted 165 */ 166 167 static int __sound_insert_unit(struct sound_unit * s, struct sound_unit **list, const struct file_operations *fops, int index, int low, int top) 168 { 169 int n=low; 170 171 if (index < 0) { /* first free */ 172 173 while (*list && (*list)->unit_minor<n) 174 list=&((*list)->next); 175 176 while(n<top) 177 { 178 /* Found a hole ? */ 179 if(*list==NULL || (*list)->unit_minor>n) 180 break; 181 list=&((*list)->next); 182 n+=SOUND_STEP; 183 } 184 185 if(n>=top) 186 return -ENOENT; 187 } else { 188 n = low+(index*16); 189 while (*list) { 190 if ((*list)->unit_minor==n) 191 return -EBUSY; 192 if ((*list)->unit_minor>n) 193 break; 194 list=&((*list)->next); 195 } 196 } 197 198 /* 199 * Fill it in 200 */ 201 202 s->unit_minor=n; 203 s->unit_fops=fops; 204 205 /* 206 * Link it 207 */ 208 209 s->next=*list; 210 *list=s; 211 212 213 return n; 214 } 215 216 /* 217 * Remove a node from the chain. Called with the lock asserted 218 */ 219 220 static struct sound_unit *__sound_remove_unit(struct sound_unit **list, int unit) 221 { 222 while(*list) 223 { 224 struct sound_unit *p=*list; 225 if(p->unit_minor==unit) 226 { 227 *list=p->next; 228 return p; 229 } 230 list=&(p->next); 231 } 232 printk(KERN_ERR "Sound device %d went missing!\n", unit); 233 return NULL; 234 } 235 236 /* 237 * This lock guards the sound loader list. 238 */ 239 240 static DEFINE_SPINLOCK(sound_loader_lock); 241 242 /* 243 * Allocate the controlling structure and add it to the sound driver 244 * list. Acquires locks as needed 245 */ 246 247 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) 248 { 249 struct sound_unit *s = kmalloc(sizeof(*s), GFP_KERNEL); 250 int r; 251 252 if (!s) 253 return -ENOMEM; 254 255 spin_lock(&sound_loader_lock); 256 retry: 257 r = __sound_insert_unit(s, list, fops, index, low, top); 258 spin_unlock(&sound_loader_lock); 259 260 if (r < 0) 261 goto fail; 262 else if (r < SOUND_STEP) 263 sprintf(s->name, "sound/%s", name); 264 else 265 sprintf(s->name, "sound/%s%d", name, r / SOUND_STEP); 266 267 if (!preclaim_oss) { 268 /* 269 * Something else might have grabbed the minor. If 270 * first free slot is requested, rescan with @low set 271 * to the next unit; otherwise, -EBUSY. 272 */ 273 r = __register_chrdev(SOUND_MAJOR, s->unit_minor, 1, s->name, 274 &soundcore_fops); 275 if (r < 0) { 276 spin_lock(&sound_loader_lock); 277 __sound_remove_unit(list, s->unit_minor); 278 if (index < 0) { 279 low = s->unit_minor + SOUND_STEP; 280 goto retry; 281 } 282 spin_unlock(&sound_loader_lock); 283 return -EBUSY; 284 } 285 } 286 287 device_create(sound_class, dev, MKDEV(SOUND_MAJOR, s->unit_minor), 288 NULL, "%s", s->name+6); 289 return s->unit_minor; 290 291 fail: 292 kfree(s); 293 return r; 294 } 295 296 /* 297 * Remove a unit. Acquires locks as needed. The drivers MUST have 298 * completed the removal before their file operations become 299 * invalid. 300 */ 301 302 static void sound_remove_unit(struct sound_unit **list, int unit) 303 { 304 struct sound_unit *p; 305 306 spin_lock(&sound_loader_lock); 307 p = __sound_remove_unit(list, unit); 308 spin_unlock(&sound_loader_lock); 309 if (p) { 310 if (!preclaim_oss) 311 __unregister_chrdev(SOUND_MAJOR, p->unit_minor, 1, 312 p->name); 313 device_destroy(sound_class, MKDEV(SOUND_MAJOR, p->unit_minor)); 314 kfree(p); 315 } 316 } 317 318 /* 319 * Allocations 320 * 321 * 0 *16 Mixers 322 * 1 *8 Sequencers 323 * 2 *16 Midi 324 * 3 *16 DSP 325 * 4 *16 SunDSP 326 * 5 *16 DSP16 327 * 6 -- sndstat (obsolete) 328 * 7 *16 unused 329 * 8 -- alternate sequencer (see above) 330 * 9 *16 raw synthesizer access 331 * 10 *16 unused 332 * 11 *16 unused 333 * 12 *16 unused 334 * 13 *16 unused 335 * 14 *16 unused 336 * 15 *16 unused 337 */ 338 339 static struct sound_unit *chains[SOUND_STEP]; 340 341 /** 342 * register_sound_special_device - register a special sound node 343 * @fops: File operations for the driver 344 * @unit: Unit number to allocate 345 * @dev: device pointer 346 * 347 * Allocate a special sound device by minor number from the sound 348 * subsystem. 349 * 350 * Return: The allocated number is returned on success. On failure, 351 * a negative error code is returned. 352 */ 353 354 int register_sound_special_device(const struct file_operations *fops, int unit, 355 struct device *dev) 356 { 357 const int chain = unit % SOUND_STEP; 358 int max_unit = 256; 359 const char *name; 360 char _name[16]; 361 362 switch (chain) { 363 case 0: 364 name = "mixer"; 365 break; 366 case 1: 367 name = "sequencer"; 368 if (unit >= SOUND_STEP) 369 goto __unknown; 370 max_unit = unit + 1; 371 break; 372 case 2: 373 name = "midi"; 374 break; 375 case 3: 376 name = "dsp"; 377 break; 378 case 4: 379 name = "audio"; 380 break; 381 case 5: 382 name = "dspW"; 383 break; 384 case 8: 385 name = "sequencer2"; 386 if (unit >= SOUND_STEP) 387 goto __unknown; 388 max_unit = unit + 1; 389 break; 390 case 9: 391 name = "dmmidi"; 392 break; 393 case 10: 394 name = "dmfm"; 395 break; 396 case 12: 397 name = "adsp"; 398 break; 399 case 13: 400 name = "amidi"; 401 break; 402 case 14: 403 name = "admmidi"; 404 break; 405 default: 406 { 407 __unknown: 408 sprintf(_name, "unknown%d", chain); 409 if (unit >= SOUND_STEP) 410 strcat(_name, "-"); 411 name = _name; 412 } 413 break; 414 } 415 return sound_insert_unit(&chains[chain], fops, -1, unit, max_unit, 416 name, 0600, dev); 417 } 418 419 EXPORT_SYMBOL(register_sound_special_device); 420 421 int register_sound_special(const struct file_operations *fops, int unit) 422 { 423 return register_sound_special_device(fops, unit, NULL); 424 } 425 426 EXPORT_SYMBOL(register_sound_special); 427 428 /** 429 * register_sound_mixer - register a mixer device 430 * @fops: File operations for the driver 431 * @dev: Unit number to allocate 432 * 433 * Allocate a mixer device. Unit is the number of the mixer requested. 434 * Pass -1 to request the next free mixer unit. 435 * 436 * Return: On success, the allocated number is returned. On failure, 437 * a negative error code is returned. 438 */ 439 440 int register_sound_mixer(const struct file_operations *fops, int dev) 441 { 442 return sound_insert_unit(&chains[0], fops, dev, 0, 128, 443 "mixer", 0600, NULL); 444 } 445 446 EXPORT_SYMBOL(register_sound_mixer); 447 448 /* 449 * DSP's are registered as a triple. Register only one and cheat 450 * in open - see below. 451 */ 452 453 /** 454 * register_sound_dsp - register a DSP device 455 * @fops: File operations for the driver 456 * @dev: Unit number to allocate 457 * 458 * Allocate a DSP device. Unit is the number of the DSP requested. 459 * Pass -1 to request the next free DSP unit. 460 * 461 * This function allocates both the audio and dsp device entries together 462 * and will always allocate them as a matching pair - eg dsp3/audio3 463 * 464 * Return: On success, the allocated number is returned. On failure, 465 * a negative error code is returned. 466 */ 467 468 int register_sound_dsp(const struct file_operations *fops, int dev) 469 { 470 return sound_insert_unit(&chains[3], fops, dev, 3, 131, 471 "dsp", 0600, NULL); 472 } 473 474 EXPORT_SYMBOL(register_sound_dsp); 475 476 /** 477 * unregister_sound_special - unregister a special sound device 478 * @unit: unit number to allocate 479 * 480 * Release a sound device that was allocated with 481 * register_sound_special(). The unit passed is the return value from 482 * the register function. 483 */ 484 485 486 void unregister_sound_special(int unit) 487 { 488 sound_remove_unit(&chains[unit % SOUND_STEP], unit); 489 } 490 491 EXPORT_SYMBOL(unregister_sound_special); 492 493 /** 494 * unregister_sound_mixer - unregister a mixer 495 * @unit: unit number to allocate 496 * 497 * Release a sound device that was allocated with register_sound_mixer(). 498 * The unit passed is the return value from the register function. 499 */ 500 501 void unregister_sound_mixer(int unit) 502 { 503 sound_remove_unit(&chains[0], unit); 504 } 505 506 EXPORT_SYMBOL(unregister_sound_mixer); 507 508 /** 509 * unregister_sound_dsp - unregister a DSP device 510 * @unit: unit number to allocate 511 * 512 * Release a sound device that was allocated with register_sound_dsp(). 513 * The unit passed is the return value from the register function. 514 * 515 * Both of the allocated units are released together automatically. 516 */ 517 518 void unregister_sound_dsp(int unit) 519 { 520 sound_remove_unit(&chains[3], unit); 521 } 522 523 524 EXPORT_SYMBOL(unregister_sound_dsp); 525 526 static struct sound_unit *__look_for_unit(int chain, int unit) 527 { 528 struct sound_unit *s; 529 530 s=chains[chain]; 531 while(s && s->unit_minor <= unit) 532 { 533 if(s->unit_minor==unit) 534 return s; 535 s=s->next; 536 } 537 return NULL; 538 } 539 540 static int soundcore_open(struct inode *inode, struct file *file) 541 { 542 int chain; 543 int unit = iminor(inode); 544 struct sound_unit *s; 545 const struct file_operations *new_fops = NULL; 546 547 chain=unit&0x0F; 548 if(chain==4 || chain==5) /* dsp/audio/dsp16 */ 549 { 550 unit&=0xF0; 551 unit|=3; 552 chain=3; 553 } 554 555 spin_lock(&sound_loader_lock); 556 s = __look_for_unit(chain, unit); 557 if (s) 558 new_fops = fops_get(s->unit_fops); 559 if (preclaim_oss && !new_fops) { 560 spin_unlock(&sound_loader_lock); 561 562 /* 563 * Please, don't change this order or code. 564 * For ALSA slot means soundcard and OSS emulation code 565 * comes as add-on modules which aren't depend on 566 * ALSA toplevel modules for soundcards, thus we need 567 * load them at first. [Jaroslav Kysela <perex@jcu.cz>] 568 */ 569 request_module("sound-slot-%i", unit>>4); 570 request_module("sound-service-%i-%i", unit>>4, chain); 571 572 /* 573 * sound-slot/service-* module aliases are scheduled 574 * for removal in favor of the standard char-major-* 575 * module aliases. For the time being, generate both 576 * the legacy and standard module aliases to ease 577 * transition. 578 */ 579 if (request_module("char-major-%d-%d", SOUND_MAJOR, unit) > 0) 580 request_module("char-major-%d", SOUND_MAJOR); 581 582 spin_lock(&sound_loader_lock); 583 s = __look_for_unit(chain, unit); 584 if (s) 585 new_fops = fops_get(s->unit_fops); 586 } 587 spin_unlock(&sound_loader_lock); 588 if (new_fops) { 589 /* 590 * We rely upon the fact that we can't be unloaded while the 591 * subdriver is there. 592 */ 593 int err = 0; 594 replace_fops(file, new_fops); 595 596 if (file->f_op->open) 597 err = file->f_op->open(inode,file); 598 599 return err; 600 } 601 return -ENODEV; 602 } 603 604 MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR); 605 606 static void cleanup_oss_soundcore(void) 607 { 608 /* We have nothing to really do here - we know the lists must be 609 empty */ 610 unregister_chrdev(SOUND_MAJOR, "sound"); 611 } 612 613 static int __init init_oss_soundcore(void) 614 { 615 if (preclaim_oss && 616 register_chrdev(SOUND_MAJOR, "sound", &soundcore_fops) < 0) { 617 printk(KERN_ERR "soundcore: sound device already in use.\n"); 618 return -EBUSY; 619 } 620 621 return 0; 622 } 623 624 #endif /* CONFIG_SOUND_OSS_CORE */ 625