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