sound/sound_core.c

   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         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         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 static 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 */