sound/core/sound.c

   1 /*
   2  *  Advanced Linux Sound Architecture
   3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   4  *
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19  *
  20  */
  21
  22 #include <linux/init.h>
  23 #include <linux/slab.h>
  24 #include <linux/time.h>
  25 #include <linux/device.h>
  26 #include <linux/module.h>
  27 #include <sound/core.h>
  28 #include <sound/minors.h>
  29 #include <sound/info.h>
  30 #include <sound/control.h>
  31 #include <sound/initval.h>
  32 #include <linux/kmod.h>
  33 #include <linux/mutex.h>
  34
  35 static int major = CONFIG_SND_MAJOR;
  36 int snd_major;
  37 EXPORT_SYMBOL(snd_major);
  38
  39 static int cards_limit = 1;
  40
  41 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
  42 MODULE_DESCRIPTION("Advanced Linux Sound Architecture driver for soundcards.");
  43 MODULE_LICENSE("GPL");
  44 module_param(major, int, 0444);
  45 MODULE_PARM_DESC(major, "Major # for sound driver.");
  46 module_param(cards_limit, int, 0444);
  47 MODULE_PARM_DESC(cards_limit, "Count of auto-loadable soundcards.");
  48 MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR);
  49
  50 /* this one holds the actual max. card number currently available.
  51  * as default, it's identical with cards_limit option.  when more
  52  * modules are loaded manually, this limit number increases, too.
  53  */
  54 int snd_ecards_limit;
  55 EXPORT_SYMBOL(snd_ecards_limit);
  56
  57 static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
  58 static DEFINE_MUTEX(sound_mutex);
  59
  60 #ifdef CONFIG_MODULES
  61
  62 /**
  63  * snd_request_card - try to load the card module
  64  * @card: the card number
  65  *
  66  * Tries to load the module "snd-card-X" for the given card number
  67  * via request_module.  Returns immediately if already loaded.
  68  */
  69 void snd_request_card(int card)
  70 {
  71         if (snd_card_locked(card))
  72                 return;
  73         if (card < 0 || card >= cards_limit)
  74                 return;
  75         request_module("snd-card-%i", card);
  76 }
  77
  78 EXPORT_SYMBOL(snd_request_card);
  79
  80 static void snd_request_other(int minor)
  81 {
  82         char *str;
  83
  84         switch (minor) {
  85         case SNDRV_MINOR_SEQUENCER:     str = "snd-seq";        break;
  86         case SNDRV_MINOR_TIMER:         str = "snd-timer";      break;
  87         default:                        return;
  88         }
  89         request_module(str);
  90 }
  91
  92 #endif  /* modular kernel */
  93
  94 /**
  95  * snd_lookup_minor_data - get user data of a registered device
  96  * @minor: the minor number
  97  * @type: device type (SNDRV_DEVICE_TYPE_XXX)
  98  *
  99  * Checks that a minor device with the specified type is registered, and returns
 100  * its user data pointer.
 101  *
 102  * This function increments the reference counter of the card instance
 103  * if an associated instance with the given minor number and type is found.
 104  * The caller must call snd_card_unref() appropriately later.
 105  */
 106 void *snd_lookup_minor_data(unsigned int minor, int type)
 107 {
 108         struct snd_minor *mreg;
 109         void *private_data;
 110
 111         if (minor >= ARRAY_SIZE(snd_minors))
 112                 return NULL;
 113         mutex_lock(&sound_mutex);
 114         mreg = snd_minors[minor];
 115         if (mreg && mreg->type == type) {
 116                 private_data = mreg->private_data;
 117                 if (mreg->card_ptr)
 118                         atomic_inc(&mreg->card_ptr->refcount);
 119         } else
 120                 private_data = NULL;
 121         mutex_unlock(&sound_mutex);
 122         return private_data;
 123 }
 124
 125 EXPORT_SYMBOL(snd_lookup_minor_data);
 126
 127 #ifdef CONFIG_MODULES
 128 static struct snd_minor *autoload_device(unsigned int minor)
 129 {
 130         int dev;
 131         mutex_unlock(&sound_mutex); /* release lock temporarily */
 132         dev = SNDRV_MINOR_DEVICE(minor);
 133         if (dev == SNDRV_MINOR_CONTROL) {
 134                 /* /dev/aloadC? */
 135                 int card = SNDRV_MINOR_CARD(minor);
 136                 if (snd_cards[card] == NULL)
 137                         snd_request_card(card);
 138         } else if (dev == SNDRV_MINOR_GLOBAL) {
 139                 /* /dev/aloadSEQ */
 140                 snd_request_other(minor);
 141         }
 142         mutex_lock(&sound_mutex); /* reacuire lock */
 143         return snd_minors[minor];
 144 }
 145 #else /* !CONFIG_MODULES */
 146 #define autoload_device(minor)  NULL
 147 #endif /* CONFIG_MODULES */
 148
 149 static int snd_open(struct inode *inode, struct file *file)
 150 {
 151         unsigned int minor = iminor(inode);
 152         struct snd_minor *mptr = NULL;
 153         const struct file_operations *old_fops;
 154         int err = 0;
 155
 156         if (minor >= ARRAY_SIZE(snd_minors))
 157                 return -ENODEV;
 158         mutex_lock(&sound_mutex);
 159         mptr = snd_minors[minor];
 160         if (mptr == NULL) {
 161                 mptr = autoload_device(minor);
 162                 if (!mptr) {
 163                         mutex_unlock(&sound_mutex);
 164                         return -ENODEV;
 165                 }
 166         }
 167         old_fops = file->f_op;
 168         file->f_op = fops_get(mptr->f_ops);
 169         if (file->f_op == NULL) {
 170                 file->f_op = old_fops;
 171                 err = -ENODEV;
 172         }
 173         mutex_unlock(&sound_mutex);
 174         if (err < 0)
 175                 return err;
 176
 177         if (file->f_op->open) {
 178                 err = file->f_op->open(inode, file);
 179                 if (err) {
 180                         fops_put(file->f_op);
 181                         file->f_op = fops_get(old_fops);
 182                 }
 183         }
 184         fops_put(old_fops);
 185         return err;
 186 }
 187
 188 static const struct file_operations snd_fops =
 189 {
 190         .owner =        THIS_MODULE,
 191         .open =         snd_open,
 192         .llseek =       noop_llseek,
 193 };
 194
 195 #ifdef CONFIG_SND_DYNAMIC_MINORS
 196 static int snd_find_free_minor(int type)
 197 {
 198         int minor;
 199
 200         /* static minors for module auto loading */
 201         if (type == SNDRV_DEVICE_TYPE_SEQUENCER)
 202                 return SNDRV_MINOR_SEQUENCER;
 203         if (type == SNDRV_DEVICE_TYPE_TIMER)
 204                 return SNDRV_MINOR_TIMER;
 205
 206         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
 207                 /* skip static minors still used for module auto loading */
 208                 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL)
 209                         continue;
 210                 if (minor == SNDRV_MINOR_SEQUENCER ||
 211                     minor == SNDRV_MINOR_TIMER)
 212                         continue;
 213                 if (!snd_minors[minor])
 214                         return minor;
 215         }
 216         return -EBUSY;
 217 }
 218 #else
 219 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
 220 {
 221         int minor;
 222
 223         switch (type) {
 224         case SNDRV_DEVICE_TYPE_SEQUENCER:
 225         case SNDRV_DEVICE_TYPE_TIMER:
 226                 minor = type;
 227                 break;
 228         case SNDRV_DEVICE_TYPE_CONTROL:
 229                 if (snd_BUG_ON(!card))
 230                         return -EINVAL;
 231                 minor = SNDRV_MINOR(card->number, type);
 232                 break;
 233         case SNDRV_DEVICE_TYPE_HWDEP:
 234         case SNDRV_DEVICE_TYPE_RAWMIDI:
 235         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 236         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 237         case SNDRV_DEVICE_TYPE_COMPRESS:
 238                 if (snd_BUG_ON(!card))
 239                         return -EINVAL;
 240                 minor = SNDRV_MINOR(card->number, type + dev);
 241                 break;
 242         default:
 243                 return -EINVAL;
 244         }
 245         if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
 246                 return -EINVAL;
 247         return minor;
 248 }
 249 #endif
 250
 251 /**
 252  * snd_register_device_for_dev - Register the ALSA device file for the card
 253  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 254  * @card: the card instance
 255  * @dev: the device index
 256  * @f_ops: the file operations
 257  * @private_data: user pointer for f_ops->open()
 258  * @name: the device file name
 259  * @device: the &struct device to link this new device to
 260  *
 261  * Registers an ALSA device file for the given card.
 262  * The operators have to be set in reg parameter.
 263  *
 264  * Returns zero if successful, or a negative error code on failure.
 265  */
 266 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
 267                                 const struct file_operations *f_ops,
 268                                 void *private_data,
 269                                 const char *name, struct device *device)
 270 {
 271         int minor;
 272         struct snd_minor *preg;
 273
 274         if (snd_BUG_ON(!name))
 275                 return -EINVAL;
 276         preg = kmalloc(sizeof *preg, GFP_KERNEL);
 277         if (preg == NULL)
 278                 return -ENOMEM;
 279         preg->type = type;
 280         preg->card = card ? card->number : -1;
 281         preg->device = dev;
 282         preg->f_ops = f_ops;
 283         preg->private_data = private_data;
 284         preg->card_ptr = card;
 285         mutex_lock(&sound_mutex);
 286 #ifdef CONFIG_SND_DYNAMIC_MINORS
 287         minor = snd_find_free_minor(type);
 288 #else
 289         minor = snd_kernel_minor(type, card, dev);
 290         if (minor >= 0 && snd_minors[minor])
 291                 minor = -EBUSY;
 292 #endif
 293         if (minor < 0) {
 294                 mutex_unlock(&sound_mutex);
 295                 kfree(preg);
 296                 return minor;
 297         }
 298         snd_minors[minor] = preg;
 299         preg->dev = device_create(sound_class, device, MKDEV(major, minor),
 300                                   private_data, "%s", name);
 301         if (IS_ERR(preg->dev)) {
 302                 snd_minors[minor] = NULL;
 303                 mutex_unlock(&sound_mutex);
 304                 minor = PTR_ERR(preg->dev);
 305                 kfree(preg);
 306                 return minor;
 307         }
 308
 309         mutex_unlock(&sound_mutex);
 310         return 0;
 311 }
 312
 313 EXPORT_SYMBOL(snd_register_device_for_dev);
 314
 315 /* find the matching minor record
 316  * return the index of snd_minor, or -1 if not found
 317  */
 318 static int find_snd_minor(int type, struct snd_card *card, int dev)
 319 {
 320         int cardnum, minor;
 321         struct snd_minor *mptr;
 322
 323         cardnum = card ? card->number : -1;
 324         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
 325                 if ((mptr = snd_minors[minor]) != NULL &&
 326                     mptr->type == type &&
 327                     mptr->card == cardnum &&
 328                     mptr->device == dev)
 329                         return minor;
 330         return -1;
 331 }
 332
 333 /**
 334  * snd_unregister_device - unregister the device on the given card
 335  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 336  * @card: the card instance
 337  * @dev: the device index
 338  *
 339  * Unregisters the device file already registered via
 340  * snd_register_device().
 341  *
 342  * Returns zero if sucecessful, or a negative error code on failure
 343  */
 344 int snd_unregister_device(int type, struct snd_card *card, int dev)
 345 {
 346         int minor;
 347
 348         mutex_lock(&sound_mutex);
 349         minor = find_snd_minor(type, card, dev);
 350         if (minor < 0) {
 351                 mutex_unlock(&sound_mutex);
 352                 return -EINVAL;
 353         }
 354
 355         device_destroy(sound_class, MKDEV(major, minor));
 356
 357         kfree(snd_minors[minor]);
 358         snd_minors[minor] = NULL;
 359         mutex_unlock(&sound_mutex);
 360         return 0;
 361 }
 362
 363 EXPORT_SYMBOL(snd_unregister_device);
 364
 365 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
 366                               struct device_attribute *attr)
 367 {
 368         int minor, ret = -EINVAL;
 369         struct device *d;
 370
 371         mutex_lock(&sound_mutex);
 372         minor = find_snd_minor(type, card, dev);
 373         if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
 374                 ret = device_create_file(d, attr);
 375         mutex_unlock(&sound_mutex);
 376         return ret;
 377
 378 }
 379
 380 EXPORT_SYMBOL(snd_add_device_sysfs_file);
 381
 382 #ifdef CONFIG_PROC_FS
 383 /*
 384  *  INFO PART
 385  */
 386
 387 static struct snd_info_entry *snd_minor_info_entry;
 388
 389 static const char *snd_device_type_name(int type)
 390 {
 391         switch (type) {
 392         case SNDRV_DEVICE_TYPE_CONTROL:
 393                 return "control";
 394         case SNDRV_DEVICE_TYPE_HWDEP:
 395                 return "hardware dependent";
 396         case SNDRV_DEVICE_TYPE_RAWMIDI:
 397                 return "raw midi";
 398         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 399                 return "digital audio playback";
 400         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 401                 return "digital audio capture";
 402         case SNDRV_DEVICE_TYPE_SEQUENCER:
 403                 return "sequencer";
 404         case SNDRV_DEVICE_TYPE_TIMER:
 405                 return "timer";
 406         default:
 407                 return "?";
 408         }
 409 }
 410
 411 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 412 {
 413         int minor;
 414         struct snd_minor *mptr;
 415
 416         mutex_lock(&sound_mutex);
 417         for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
 418                 if (!(mptr = snd_minors[minor]))
 419                         continue;
 420                 if (mptr->card >= 0) {
 421                         if (mptr->device >= 0)
 422                                 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
 423                                             minor, mptr->card, mptr->device,
 424                                             snd_device_type_name(mptr->type));
 425                         else
 426                                 snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
 427                                             minor, mptr->card,
 428                                             snd_device_type_name(mptr->type));
 429                 } else
 430                         snd_iprintf(buffer, "%3i:        : %s\n", minor,
 431                                     snd_device_type_name(mptr->type));
 432         }
 433         mutex_unlock(&sound_mutex);
 434 }
 435
 436 int __init snd_minor_info_init(void)
 437 {
 438         struct snd_info_entry *entry;
 439
 440         entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
 441         if (entry) {
 442                 entry->c.text.read = snd_minor_info_read;
 443                 if (snd_info_register(entry) < 0) {
 444                         snd_info_free_entry(entry);
 445                         entry = NULL;
 446                 }
 447         }
 448         snd_minor_info_entry = entry;
 449         return 0;
 450 }
 451
 452 int __exit snd_minor_info_done(void)
 453 {
 454         snd_info_free_entry(snd_minor_info_entry);
 455         return 0;
 456 }
 457 #endif /* CONFIG_PROC_FS */
 458
 459 /*
 460  *  INIT PART
 461  */
 462
 463 static int __init alsa_sound_init(void)
 464 {
 465         snd_major = major;
 466         snd_ecards_limit = cards_limit;
 467         if (register_chrdev(major, "alsa", &snd_fops)) {
 468                 snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
 469                 return -EIO;
 470         }
 471         if (snd_info_init() < 0) {
 472                 unregister_chrdev(major, "alsa");
 473                 return -ENOMEM;
 474         }
 475         snd_info_minor_register();
 476 #ifndef MODULE
 477         printk(KERN_INFO "Advanced Linux Sound Architecture Driver Initialized.\n");
 478 #endif
 479         return 0;
 480 }
 481
 482 static void __exit alsa_sound_exit(void)
 483 {
 484         snd_info_minor_unregister();
 485         snd_info_done();
 486         unregister_chrdev(major, "alsa");
 487 }
 488
 489 subsys_initcall(alsa_sound_init);
 490 module_exit(alsa_sound_exit);