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