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