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/smp_lock.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 device_create_drvdata(sound_class, dev, 175 MKDEV(SOUND_MAJOR, s->unit_minor), 176 NULL, s->name+6); 177 return r; 178 179 fail: 180 kfree(s); 181 return r; 182 } 183 184 /* 185 * Remove a unit. Acquires locks as needed. The drivers MUST have 186 * completed the removal before their file operations become 187 * invalid. 188 */ 189 190 static void sound_remove_unit(struct sound_unit **list, int unit) 191 { 192 struct sound_unit *p; 193 194 spin_lock(&sound_loader_lock); 195 p = __sound_remove_unit(list, unit); 196 spin_unlock(&sound_loader_lock); 197 if (p) { 198 device_destroy(sound_class, MKDEV(SOUND_MAJOR, p->unit_minor)); 199 kfree(p); 200 } 201 } 202 203 /* 204 * Allocations 205 * 206 * 0 *16 Mixers 207 * 1 *8 Sequencers 208 * 2 *16 Midi 209 * 3 *16 DSP 210 * 4 *16 SunDSP 211 * 5 *16 DSP16 212 * 6 -- sndstat (obsolete) 213 * 7 *16 unused 214 * 8 -- alternate sequencer (see above) 215 * 9 *16 raw synthesizer access 216 * 10 *16 unused 217 * 11 *16 unused 218 * 12 *16 unused 219 * 13 *16 unused 220 * 14 *16 unused 221 * 15 *16 unused 222 */ 223 224 static struct sound_unit *chains[SOUND_STEP]; 225 226 /** 227 * register_sound_special_device - register a special sound node 228 * @fops: File operations for the driver 229 * @unit: Unit number to allocate 230 * @dev: device pointer 231 * 232 * Allocate a special sound device by minor number from the sound 233 * subsystem. The allocated number is returned on succes. On failure 234 * a negative error code is returned. 235 */ 236 237 int register_sound_special_device(const struct file_operations *fops, int unit, 238 struct device *dev) 239 { 240 const int chain = unit % SOUND_STEP; 241 int max_unit = 128 + chain; 242 const char *name; 243 char _name[16]; 244 245 switch (chain) { 246 case 0: 247 name = "mixer"; 248 break; 249 case 1: 250 name = "sequencer"; 251 if (unit >= SOUND_STEP) 252 goto __unknown; 253 max_unit = unit + 1; 254 break; 255 case 2: 256 name = "midi"; 257 break; 258 case 3: 259 name = "dsp"; 260 break; 261 case 4: 262 name = "audio"; 263 break; 264 case 8: 265 name = "sequencer2"; 266 if (unit >= SOUND_STEP) 267 goto __unknown; 268 max_unit = unit + 1; 269 break; 270 case 9: 271 name = "dmmidi"; 272 break; 273 case 10: 274 name = "dmfm"; 275 break; 276 case 12: 277 name = "adsp"; 278 break; 279 case 13: 280 name = "amidi"; 281 break; 282 case 14: 283 name = "admmidi"; 284 break; 285 default: 286 { 287 __unknown: 288 sprintf(_name, "unknown%d", chain); 289 if (unit >= SOUND_STEP) 290 strcat(_name, "-"); 291 name = _name; 292 } 293 break; 294 } 295 return sound_insert_unit(&chains[chain], fops, -1, unit, max_unit, 296 name, S_IRUSR | S_IWUSR, dev); 297 } 298 299 EXPORT_SYMBOL(register_sound_special_device); 300 301 int register_sound_special(const struct file_operations *fops, int unit) 302 { 303 return register_sound_special_device(fops, unit, NULL); 304 } 305 306 EXPORT_SYMBOL(register_sound_special); 307 308 /** 309 * register_sound_mixer - register a mixer device 310 * @fops: File operations for the driver 311 * @dev: Unit number to allocate 312 * 313 * Allocate a mixer device. Unit is the number of the mixer requested. 314 * Pass -1 to request the next free mixer unit. On success the allocated 315 * number is returned, on failure a negative error code is returned. 316 */ 317 318 int register_sound_mixer(const struct file_operations *fops, int dev) 319 { 320 return sound_insert_unit(&chains[0], fops, dev, 0, 128, 321 "mixer", S_IRUSR | S_IWUSR, NULL); 322 } 323 324 EXPORT_SYMBOL(register_sound_mixer); 325 326 /** 327 * register_sound_midi - register a midi device 328 * @fops: File operations for the driver 329 * @dev: Unit number to allocate 330 * 331 * Allocate a midi device. Unit is the number of the midi device requested. 332 * Pass -1 to request the next free midi unit. On success the allocated 333 * number is returned, on failure a negative error code is returned. 334 */ 335 336 int register_sound_midi(const struct file_operations *fops, int dev) 337 { 338 return sound_insert_unit(&chains[2], fops, dev, 2, 130, 339 "midi", S_IRUSR | S_IWUSR, NULL); 340 } 341 342 EXPORT_SYMBOL(register_sound_midi); 343 344 /* 345 * DSP's are registered as a triple. Register only one and cheat 346 * in open - see below. 347 */ 348 349 /** 350 * register_sound_dsp - register a DSP device 351 * @fops: File operations for the driver 352 * @dev: Unit number to allocate 353 * 354 * Allocate a DSP device. Unit is the number of the DSP requested. 355 * Pass -1 to request the next free DSP unit. On success the allocated 356 * number is returned, on failure a negative error code is returned. 357 * 358 * This function allocates both the audio and dsp device entries together 359 * and will always allocate them as a matching pair - eg dsp3/audio3 360 */ 361 362 int register_sound_dsp(const struct file_operations *fops, int dev) 363 { 364 return sound_insert_unit(&chains[3], fops, dev, 3, 131, 365 "dsp", S_IWUSR | S_IRUSR, NULL); 366 } 367 368 EXPORT_SYMBOL(register_sound_dsp); 369 370 /** 371 * unregister_sound_special - unregister a special sound device 372 * @unit: unit number to allocate 373 * 374 * Release a sound device that was allocated with 375 * register_sound_special(). The unit passed is the return value from 376 * the register function. 377 */ 378 379 380 void unregister_sound_special(int unit) 381 { 382 sound_remove_unit(&chains[unit % SOUND_STEP], unit); 383 } 384 385 EXPORT_SYMBOL(unregister_sound_special); 386 387 /** 388 * unregister_sound_mixer - unregister a mixer 389 * @unit: unit number to allocate 390 * 391 * Release a sound device that was allocated with register_sound_mixer(). 392 * The unit passed is the return value from the register function. 393 */ 394 395 void unregister_sound_mixer(int unit) 396 { 397 sound_remove_unit(&chains[0], unit); 398 } 399 400 EXPORT_SYMBOL(unregister_sound_mixer); 401 402 /** 403 * unregister_sound_midi - unregister a midi device 404 * @unit: unit number to allocate 405 * 406 * Release a sound device that was allocated with register_sound_midi(). 407 * The unit passed is the return value from the register function. 408 */ 409 410 void unregister_sound_midi(int unit) 411 { 412 return sound_remove_unit(&chains[2], unit); 413 } 414 415 EXPORT_SYMBOL(unregister_sound_midi); 416 417 /** 418 * unregister_sound_dsp - unregister a DSP device 419 * @unit: unit number to allocate 420 * 421 * Release a sound device that was allocated with register_sound_dsp(). 422 * The unit passed is the return value from the register function. 423 * 424 * Both of the allocated units are released together automatically. 425 */ 426 427 void unregister_sound_dsp(int unit) 428 { 429 return sound_remove_unit(&chains[3], unit); 430 } 431 432 433 EXPORT_SYMBOL(unregister_sound_dsp); 434 435 /* 436 * Now our file operations 437 */ 438 439 static int soundcore_open(struct inode *, struct file *); 440 441 static const struct file_operations soundcore_fops= 442 { 443 /* We must have an owner or the module locking fails */ 444 .owner = THIS_MODULE, 445 .open = soundcore_open, 446 }; 447 448 static struct sound_unit *__look_for_unit(int chain, int unit) 449 { 450 struct sound_unit *s; 451 452 s=chains[chain]; 453 while(s && s->unit_minor <= unit) 454 { 455 if(s->unit_minor==unit) 456 return s; 457 s=s->next; 458 } 459 return NULL; 460 } 461 462 int soundcore_open(struct inode *inode, struct file *file) 463 { 464 int chain; 465 int unit = iminor(inode); 466 struct sound_unit *s; 467 const struct file_operations *new_fops = NULL; 468 469 lock_kernel (); 470 471 chain=unit&0x0F; 472 if(chain==4 || chain==5) /* dsp/audio/dsp16 */ 473 { 474 unit&=0xF0; 475 unit|=3; 476 chain=3; 477 } 478 479 spin_lock(&sound_loader_lock); 480 s = __look_for_unit(chain, unit); 481 if (s) 482 new_fops = fops_get(s->unit_fops); 483 if (!new_fops) { 484 spin_unlock(&sound_loader_lock); 485 /* 486 * Please, don't change this order or code. 487 * For ALSA slot means soundcard and OSS emulation code 488 * comes as add-on modules which aren't depend on 489 * ALSA toplevel modules for soundcards, thus we need 490 * load them at first. [Jaroslav Kysela <perex@jcu.cz>] 491 */ 492 request_module("sound-slot-%i", unit>>4); 493 request_module("sound-service-%i-%i", unit>>4, chain); 494 spin_lock(&sound_loader_lock); 495 s = __look_for_unit(chain, unit); 496 if (s) 497 new_fops = fops_get(s->unit_fops); 498 } 499 if (new_fops) { 500 /* 501 * We rely upon the fact that we can't be unloaded while the 502 * subdriver is there, so if ->open() is successful we can 503 * safely drop the reference counter and if it is not we can 504 * revert to old ->f_op. Ugly, indeed, but that's the cost of 505 * switching ->f_op in the first place. 506 */ 507 int err = 0; 508 const struct file_operations *old_fops = file->f_op; 509 file->f_op = new_fops; 510 spin_unlock(&sound_loader_lock); 511 if(file->f_op->open) 512 err = file->f_op->open(inode,file); 513 if (err) { 514 fops_put(file->f_op); 515 file->f_op = fops_get(old_fops); 516 } 517 fops_put(old_fops); 518 unlock_kernel(); 519 return err; 520 } 521 spin_unlock(&sound_loader_lock); 522 unlock_kernel(); 523 return -ENODEV; 524 } 525 526 MODULE_DESCRIPTION("Core sound module"); 527 MODULE_AUTHOR("Alan Cox"); 528 MODULE_LICENSE("GPL"); 529 MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR); 530 531 static void __exit cleanup_soundcore(void) 532 { 533 /* We have nothing to really do here - we know the lists must be 534 empty */ 535 unregister_chrdev(SOUND_MAJOR, "sound"); 536 class_destroy(sound_class); 537 } 538 539 static int __init init_soundcore(void) 540 { 541 if (register_chrdev(SOUND_MAJOR, "sound", &soundcore_fops)==-1) { 542 printk(KERN_ERR "soundcore: sound device already in use.\n"); 543 return -EBUSY; 544 } 545 sound_class = class_create(THIS_MODULE, "sound"); 546 if (IS_ERR(sound_class)) 547 return PTR_ERR(sound_class); 548 549 return 0; 550 } 551 552 module_init(init_soundcore); 553 module_exit(cleanup_soundcore); 554