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 <linux/kdev_t.h>
  14 #include <linux/major.h>
  15 #include <sound/core.h>
  16
  17 #ifdef CONFIG_SOUND_OSS_CORE
  18 static int __init init_oss_soundcore(void);
  19 static void cleanup_oss_soundcore(void);
  20 #else
  21 static inline int init_oss_soundcore(void)      { return 0; }
  22 static inline void cleanup_oss_soundcore(void)  { }
  23 #endif
  24
  25 struct class *sound_class;
  26 EXPORT_SYMBOL(sound_class);
  27
  28 MODULE_DESCRIPTION("Core sound module");
  29 MODULE_AUTHOR("Alan Cox");
  30 MODULE_LICENSE("GPL");
  31
  32 static char *sound_nodename(struct device *dev)
  33 {
  34         if (MAJOR(dev->devt) == SOUND_MAJOR)
  35                 return NULL;
  36         return kasprintf(GFP_KERNEL, "snd/%s", dev_name(dev));
  37 }
  38
  39 static int __init init_soundcore(void)
  40 {
  41         int rc;
  42
  43         rc = init_oss_soundcore();
  44         if (rc)
  45                 return rc;
  46
  47         sound_class = class_create(THIS_MODULE, "sound");
  48         if (IS_ERR(sound_class)) {
  49                 cleanup_oss_soundcore();
  50                 return PTR_ERR(sound_class);
  51         }
  52
  53         sound_class->nodename = sound_nodename;
  54
  55         return 0;
  56 }
  57
  58 static void __exit cleanup_soundcore(void)
  59 {
  60         cleanup_oss_soundcore();
  61         class_destroy(sound_class);
  62 }
  63
  64 module_init(init_soundcore);
  65 module_exit(cleanup_soundcore);
  66
  67
  68 #ifdef CONFIG_SOUND_OSS_CORE
  69 /*
  70  *      OSS sound core handling. Breaks out sound functions to submodules
  71  *
  72  *      Author:         Alan Cox <alan@lxorguk.ukuu.org.uk>
  73  *
  74  *      Fixes:
  75  *
  76  *
  77  *      This program is free software; you can redistribute it and/or
  78  *      modify it under the terms of the GNU General Public License
  79  *      as published by the Free Software Foundation; either version
  80  *      2 of the License, or (at your option) any later version.
  81  *
  82  *                         --------------------
  83  *
  84  *      Top level handler for the sound subsystem. Various devices can
  85  *      plug into this. The fact they don't all go via OSS doesn't mean
  86  *      they don't have to implement the OSS API. There is a lot of logic
  87  *      to keeping much of the OSS weight out of the code in a compatibility
  88  *      module, but it's up to the driver to rember to load it...
  89  *
  90  *      The code provides a set of functions for registration of devices
  91  *      by type. This is done rather than providing a single call so that
  92  *      we can hide any future changes in the internals (eg when we go to
  93  *      32bit dev_t) from the modules and their interface.
  94  *
  95  *      Secondly we need to allocate the dsp, dsp16 and audio devices as
  96  *      one. Thus we misuse the chains a bit to simplify this.
  97  *
  98  *      Thirdly to make it more fun and for 2.3.x and above we do all
  99  *      of this using fine grained locking.
 100  *
 101  *      FIXME: we have to resolve modules and fine grained load/unload
 102  *      locking at some point in 2.3.x.
 103  */
 104
 105 #include <linux/init.h>
 106 #include <linux/slab.h>
 107 #include <linux/smp_lock.h>
 108 #include <linux/types.h>
 109 #include <linux/kernel.h>
 110 #include <linux/sound.h>
 111 #include <linux/kmod.h>
 112
 113 #define SOUND_STEP 16
 114
 115 struct sound_unit
 116 {
 117         int unit_minor;
 118         const struct file_operations *unit_fops;
 119         struct sound_unit *next;
 120         char name[32];
 121 };
 122
 123 #ifdef CONFIG_SOUND_MSNDCLAS
 124 extern int msnd_classic_init(void);
 125 #endif
 126 #ifdef CONFIG_SOUND_MSNDPIN
 127 extern int msnd_pinnacle_init(void);
 128 #endif
 129
 130 /*
 131  *      Low level list operator. Scan the ordered list, find a hole and
 132  *      join into it. Called with the lock asserted
 133  */
 134
 135 static int __sound_insert_unit(struct sound_unit * s, struct sound_unit **list, const struct file_operations *fops, int index, int low, int top)
 136 {
 137         int n=low;
 138
 139         if (index < 0) {        /* first free */
 140
 141                 while (*list && (*list)->unit_minor<n)
 142                         list=&((*list)->next);
 143
 144                 while(n<top)
 145                 {
 146                         /* Found a hole ? */
 147                         if(*list==NULL || (*list)->unit_minor>n)
 148                                 break;
 149                         list=&((*list)->next);
 150                         n+=SOUND_STEP;
 151                 }
 152
 153                 if(n>=top)
 154                         return -ENOENT;
 155         } else {
 156                 n = low+(index*16);
 157                 while (*list) {
 158                         if ((*list)->unit_minor==n)
 159                                 return -EBUSY;
 160                         if ((*list)->unit_minor>n)
 161                                 break;
 162                         list=&((*list)->next);
 163                 }
 164         }
 165
 166         /*
 167          *      Fill it in
 168          */
 169
 170         s->unit_minor=n;
 171         s->unit_fops=fops;
 172
 173         /*
 174          *      Link it
 175          */
 176
 177         s->next=*list;
 178         *list=s;
 179
 180
 181         return n;
 182 }
 183
 184 /*
 185  *      Remove a node from the chain. Called with the lock asserted
 186  */
 187
 188 static struct sound_unit *__sound_remove_unit(struct sound_unit **list, int unit)
 189 {
 190         while(*list)
 191         {
 192                 struct sound_unit *p=*list;
 193                 if(p->unit_minor==unit)
 194                 {
 195                         *list=p->next;
 196                         return p;
 197                 }
 198                 list=&(p->next);
 199         }
 200         printk(KERN_ERR "Sound device %d went missing!\n", unit);
 201         return NULL;
 202 }
 203
 204 /*
 205  *      This lock guards the sound loader list.
 206  */
 207
 208 static DEFINE_SPINLOCK(sound_loader_lock);
 209
 210 /*
 211  *      Allocate the controlling structure and add it to the sound driver
 212  *      list. Acquires locks as needed
 213  */
 214
 215 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)
 216 {
 217         struct sound_unit *s = kmalloc(sizeof(*s), GFP_KERNEL);
 218         int r;
 219
 220         if (!s)
 221                 return -ENOMEM;
 222
 223         spin_lock(&sound_loader_lock);
 224         r = __sound_insert_unit(s, list, fops, index, low, top);
 225         spin_unlock(&sound_loader_lock);
 226
 227         if (r < 0)
 228                 goto fail;
 229         else if (r < SOUND_STEP)
 230                 sprintf(s->name, "sound/%s", name);
 231         else
 232                 sprintf(s->name, "sound/%s%d", name, r / SOUND_STEP);
 233
 234         device_create(sound_class, dev, MKDEV(SOUND_MAJOR, s->unit_minor),
 235                       NULL, s->name+6);
 236         return r;
 237
 238  fail:
 239         kfree(s);
 240         return r;
 241 }
 242
 243 /*
 244  *      Remove a unit. Acquires locks as needed. The drivers MUST have
 245  *      completed the removal before their file operations become
 246  *      invalid.
 247  */
 248
 249 static void sound_remove_unit(struct sound_unit **list, int unit)
 250 {
 251         struct sound_unit *p;
 252
 253         spin_lock(&sound_loader_lock);
 254         p = __sound_remove_unit(list, unit);
 255         spin_unlock(&sound_loader_lock);
 256         if (p) {
 257                 device_destroy(sound_class, MKDEV(SOUND_MAJOR, p->unit_minor));
 258                 kfree(p);
 259         }
 260 }
 261
 262 /*
 263  *      Allocations
 264  *
 265  *      0       *16             Mixers
 266  *      1       *8              Sequencers
 267  *      2       *16             Midi
 268  *      3       *16             DSP
 269  *      4       *16             SunDSP
 270  *      5       *16             DSP16
 271  *      6       --              sndstat (obsolete)
 272  *      7       *16             unused
 273  *      8       --              alternate sequencer (see above)
 274  *      9       *16             raw synthesizer access
 275  *      10      *16             unused
 276  *      11      *16             unused
 277  *      12      *16             unused
 278  *      13      *16             unused
 279  *      14      *16             unused
 280  *      15      *16             unused
 281  */
 282
 283 static struct sound_unit *chains[SOUND_STEP];
 284
 285 /**
 286  *      register_sound_special_device - register a special sound node
 287  *      @fops: File operations for the driver
 288  *      @unit: Unit number to allocate
 289  *      @dev: device pointer
 290  *
 291  *      Allocate a special sound device by minor number from the sound
 292  *      subsystem. The allocated number is returned on succes. On failure
 293  *      a negative error code is returned.
 294  */
 295
 296 int register_sound_special_device(const struct file_operations *fops, int unit,
 297                                   struct device *dev)
 298 {
 299         const int chain = unit % SOUND_STEP;
 300         int max_unit = 128 + chain;
 301         const char *name;
 302         char _name[16];
 303
 304         switch (chain) {
 305             case 0:
 306                 name = "mixer";
 307                 break;
 308             case 1:
 309                 name = "sequencer";
 310                 if (unit >= SOUND_STEP)
 311                         goto __unknown;
 312                 max_unit = unit + 1;
 313                 break;
 314             case 2:
 315                 name = "midi";
 316                 break;
 317             case 3:
 318                 name = "dsp";
 319                 break;
 320             case 4:
 321                 name = "audio";
 322                 break;
 323             case 8:
 324                 name = "sequencer2";
 325                 if (unit >= SOUND_STEP)
 326                         goto __unknown;
 327                 max_unit = unit + 1;
 328                 break;
 329             case 9:
 330                 name = "dmmidi";
 331                 break;
 332             case 10:
 333                 name = "dmfm";
 334                 break;
 335             case 12:
 336                 name = "adsp";
 337                 break;
 338             case 13:
 339                 name = "amidi";
 340                 break;
 341             case 14:
 342                 name = "admmidi";
 343                 break;
 344             default:
 345                 {
 346                     __unknown:
 347                         sprintf(_name, "unknown%d", chain);
 348                         if (unit >= SOUND_STEP)
 349                                 strcat(_name, "-");
 350                         name = _name;
 351                 }
 352                 break;
 353         }
 354         return sound_insert_unit(&chains[chain], fops, -1, unit, max_unit,
 355                                  name, S_IRUSR | S_IWUSR, dev);
 356 }
 357
 358 EXPORT_SYMBOL(register_sound_special_device);
 359
 360 int register_sound_special(const struct file_operations *fops, int unit)
 361 {
 362         return register_sound_special_device(fops, unit, NULL);
 363 }
 364
 365 EXPORT_SYMBOL(register_sound_special);
 366
 367 /**
 368  *      register_sound_mixer - register a mixer device
 369  *      @fops: File operations for the driver
 370  *      @dev: Unit number to allocate
 371  *
 372  *      Allocate a mixer device. Unit is the number of the mixer requested.
 373  *      Pass -1 to request the next free mixer unit. On success the allocated
 374  *      number is returned, on failure a negative error code is returned.
 375  */
 376
 377 int register_sound_mixer(const struct file_operations *fops, int dev)
 378 {
 379         return sound_insert_unit(&chains[0], fops, dev, 0, 128,
 380                                  "mixer", S_IRUSR | S_IWUSR, NULL);
 381 }
 382
 383 EXPORT_SYMBOL(register_sound_mixer);
 384
 385 /**
 386  *      register_sound_midi - register a midi device
 387  *      @fops: File operations for the driver
 388  *      @dev: Unit number to allocate
 389  *
 390  *      Allocate a midi device. Unit is the number of the midi device requested.
 391  *      Pass -1 to request the next free midi unit. On success the allocated
 392  *      number is returned, on failure a negative error code is returned.
 393  */
 394
 395 int register_sound_midi(const struct file_operations *fops, int dev)
 396 {
 397         return sound_insert_unit(&chains[2], fops, dev, 2, 130,
 398                                  "midi", S_IRUSR | S_IWUSR, NULL);
 399 }
 400
 401 EXPORT_SYMBOL(register_sound_midi);
 402
 403 /*
 404  *      DSP's are registered as a triple. Register only one and cheat
 405  *      in open - see below.
 406  */
 407
 408 /**
 409  *      register_sound_dsp - register a DSP device
 410  *      @fops: File operations for the driver
 411  *      @dev: Unit number to allocate
 412  *
 413  *      Allocate a DSP device. Unit is the number of the DSP requested.
 414  *      Pass -1 to request the next free DSP unit. On success the allocated
 415  *      number is returned, on failure a negative error code is returned.
 416  *
 417  *      This function allocates both the audio and dsp device entries together
 418  *      and will always allocate them as a matching pair - eg dsp3/audio3
 419  */
 420
 421 int register_sound_dsp(const struct file_operations *fops, int dev)
 422 {
 423         return sound_insert_unit(&chains[3], fops, dev, 3, 131,
 424                                  "dsp", S_IWUSR | S_IRUSR, NULL);
 425 }
 426
 427 EXPORT_SYMBOL(register_sound_dsp);
 428
 429 /**
 430  *      unregister_sound_special - unregister a special sound device
 431  *      @unit: unit number to allocate
 432  *
 433  *      Release a sound device that was allocated with
 434  *      register_sound_special(). The unit passed is the return value from
 435  *      the register function.
 436  */
 437
 438
 439 void unregister_sound_special(int unit)
 440 {
 441         sound_remove_unit(&chains[unit % SOUND_STEP], unit);
 442 }
 443
 444 EXPORT_SYMBOL(unregister_sound_special);
 445
 446 /**
 447  *      unregister_sound_mixer - unregister a mixer
 448  *      @unit: unit number to allocate
 449  *
 450  *      Release a sound device that was allocated with register_sound_mixer().
 451  *      The unit passed is the return value from the register function.
 452  */
 453
 454 void unregister_sound_mixer(int unit)
 455 {
 456         sound_remove_unit(&chains[0], unit);
 457 }
 458
 459 EXPORT_SYMBOL(unregister_sound_mixer);
 460
 461 /**
 462  *      unregister_sound_midi - unregister a midi device
 463  *      @unit: unit number to allocate
 464  *
 465  *      Release a sound device that was allocated with register_sound_midi().
 466  *      The unit passed is the return value from the register function.
 467  */
 468
 469 void unregister_sound_midi(int unit)
 470 {
 471         sound_remove_unit(&chains[2], unit);
 472 }
 473
 474 EXPORT_SYMBOL(unregister_sound_midi);
 475
 476 /**
 477  *      unregister_sound_dsp - unregister a DSP device
 478  *      @unit: unit number to allocate
 479  *
 480  *      Release a sound device that was allocated with register_sound_dsp().
 481  *      The unit passed is the return value from the register function.
 482  *
 483  *      Both of the allocated units are released together automatically.
 484  */
 485
 486 void unregister_sound_dsp(int unit)
 487 {
 488         sound_remove_unit(&chains[3], unit);
 489 }
 490
 491
 492 EXPORT_SYMBOL(unregister_sound_dsp);
 493
 494 /*
 495  *      Now our file operations
 496  */
 497
 498 static int soundcore_open(struct inode *, struct file *);
 499
 500 static const struct file_operations soundcore_fops=
 501 {
 502         /* We must have an owner or the module locking fails */
 503         .owner  = THIS_MODULE,
 504         .open   = soundcore_open,
 505 };
 506
 507 static struct sound_unit *__look_for_unit(int chain, int unit)
 508 {
 509         struct sound_unit *s;
 510
 511         s=chains[chain];
 512         while(s && s->unit_minor <= unit)
 513         {
 514                 if(s->unit_minor==unit)
 515                         return s;
 516                 s=s->next;
 517         }
 518         return NULL;
 519 }
 520
 521 static int soundcore_open(struct inode *inode, struct file *file)
 522 {
 523         int chain;
 524         int unit = iminor(inode);
 525         struct sound_unit *s;
 526         const struct file_operations *new_fops = NULL;
 527
 528         lock_kernel ();
 529
 530         chain=unit&0x0F;
 531         if(chain==4 || chain==5)        /* dsp/audio/dsp16 */
 532         {
 533                 unit&=0xF0;
 534                 unit|=3;
 535                 chain=3;
 536         }
 537
 538         spin_lock(&sound_loader_lock);
 539         s = __look_for_unit(chain, unit);
 540         if (s)
 541                 new_fops = fops_get(s->unit_fops);
 542         if (!new_fops) {
 543                 spin_unlock(&sound_loader_lock);
 544                 /*
 545                  *  Please, don't change this order or code.
 546                  *  For ALSA slot means soundcard and OSS emulation code
 547                  *  comes as add-on modules which aren't depend on
 548                  *  ALSA toplevel modules for soundcards, thus we need
 549                  *  load them at first.   [Jaroslav Kysela <perex@jcu.cz>]
 550                  */
 551                 request_module("sound-slot-%i", unit>>4);
 552                 request_module("sound-service-%i-%i", unit>>4, chain);
 553                 spin_lock(&sound_loader_lock);
 554                 s = __look_for_unit(chain, unit);
 555                 if (s)
 556                         new_fops = fops_get(s->unit_fops);
 557         }
 558         if (new_fops) {
 559                 /*
 560                  * We rely upon the fact that we can't be unloaded while the
 561                  * subdriver is there, so if ->open() is successful we can
 562                  * safely drop the reference counter and if it is not we can
 563                  * revert to old ->f_op. Ugly, indeed, but that's the cost of
 564                  * switching ->f_op in the first place.
 565                  */
 566                 int err = 0;
 567                 const struct file_operations *old_fops = file->f_op;
 568                 file->f_op = new_fops;
 569                 spin_unlock(&sound_loader_lock);
 570                 if(file->f_op->open)
 571                         err = file->f_op->open(inode,file);
 572                 if (err) {
 573                         fops_put(file->f_op);
 574                         file->f_op = fops_get(old_fops);
 575                 }
 576                 fops_put(old_fops);
 577                 unlock_kernel();
 578                 return err;
 579         }
 580         spin_unlock(&sound_loader_lock);
 581         unlock_kernel();
 582         return -ENODEV;
 583 }
 584
 585 MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR);
 586
 587 static void cleanup_oss_soundcore(void)
 588 {
 589         /* We have nothing to really do here - we know the lists must be
 590            empty */
 591         unregister_chrdev(SOUND_MAJOR, "sound");
 592 }
 593
 594 static int __init init_oss_soundcore(void)
 595 {
 596         if (register_chrdev(SOUND_MAJOR, "sound", &soundcore_fops)==-1) {
 597                 printk(KERN_ERR "soundcore: sound device already in use.\n");
 598                 return -EBUSY;
 599         }
 600
 601         return 0;
 602 }
 603
 604 #endif /* CONFIG_SOUND_OSS_CORE */