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