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