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  * Return: The user data pointer if the specified device is found. %NULL
 107  * otherwise.
 108  */
 109 void *snd_lookup_minor_data(unsigned int minor, int type)
 110 {
 111         struct snd_minor *mreg;
 112         void *private_data;
 113
 114         if (minor >= ARRAY_SIZE(snd_minors))
 115                 return NULL;
 116         mutex_lock(&sound_mutex);
 117         mreg = snd_minors[minor];
 118         if (mreg && mreg->type == type) {
 119                 private_data = mreg->private_data;
 120                 if (private_data && mreg->card_ptr)
 121                         atomic_inc(&mreg->card_ptr->refcount);
 122         } else
 123                 private_data = NULL;
 124         mutex_unlock(&sound_mutex);
 125         return private_data;
 126 }
 127
 128 EXPORT_SYMBOL(snd_lookup_minor_data);
 129
 130 #ifdef CONFIG_MODULES
 131 static struct snd_minor *autoload_device(unsigned int minor)
 132 {
 133         int dev;
 134         mutex_unlock(&sound_mutex); /* release lock temporarily */
 135         dev = SNDRV_MINOR_DEVICE(minor);
 136         if (dev == SNDRV_MINOR_CONTROL) {
 137                 /* /dev/aloadC? */
 138                 int card = SNDRV_MINOR_CARD(minor);
 139                 if (snd_cards[card] == NULL)
 140                         snd_request_card(card);
 141         } else if (dev == SNDRV_MINOR_GLOBAL) {
 142                 /* /dev/aloadSEQ */
 143                 snd_request_other(minor);
 144         }
 145         mutex_lock(&sound_mutex); /* reacuire lock */
 146         return snd_minors[minor];
 147 }
 148 #else /* !CONFIG_MODULES */
 149 #define autoload_device(minor)  NULL
 150 #endif /* CONFIG_MODULES */
 151
 152 static int snd_open(struct inode *inode, struct file *file)
 153 {
 154         unsigned int minor = iminor(inode);
 155         struct snd_minor *mptr = NULL;
 156         const struct file_operations *old_fops;
 157         int err = 0;
 158
 159         if (minor >= ARRAY_SIZE(snd_minors))
 160                 return -ENODEV;
 161         mutex_lock(&sound_mutex);
 162         mptr = snd_minors[minor];
 163         if (mptr == NULL) {
 164                 mptr = autoload_device(minor);
 165                 if (!mptr) {
 166                         mutex_unlock(&sound_mutex);
 167                         return -ENODEV;
 168                 }
 169         }
 170         old_fops = file->f_op;
 171         file->f_op = fops_get(mptr->f_ops);
 172         if (file->f_op == NULL) {
 173                 file->f_op = old_fops;
 174                 err = -ENODEV;
 175         }
 176         mutex_unlock(&sound_mutex);
 177         if (err < 0)
 178                 return err;
 179
 180         if (file->f_op->open) {
 181                 err = file->f_op->open(inode, file);
 182                 if (err) {
 183                         fops_put(file->f_op);
 184                         file->f_op = fops_get(old_fops);
 185                 }
 186         }
 187         fops_put(old_fops);
 188         return err;
 189 }
 190
 191 static const struct file_operations snd_fops =
 192 {
 193         .owner =        THIS_MODULE,
 194         .open =         snd_open,
 195         .llseek =       noop_llseek,
 196 };
 197
 198 #ifdef CONFIG_SND_DYNAMIC_MINORS
 199 static int snd_find_free_minor(int type)
 200 {
 201         int minor;
 202
 203         /* static minors for module auto loading */
 204         if (type == SNDRV_DEVICE_TYPE_SEQUENCER)
 205                 return SNDRV_MINOR_SEQUENCER;
 206         if (type == SNDRV_DEVICE_TYPE_TIMER)
 207                 return SNDRV_MINOR_TIMER;
 208
 209         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
 210                 /* skip static minors still used for module auto loading */
 211                 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL)
 212                         continue;
 213                 if (minor == SNDRV_MINOR_SEQUENCER ||
 214                     minor == SNDRV_MINOR_TIMER)
 215                         continue;
 216                 if (!snd_minors[minor])
 217                         return minor;
 218         }
 219         return -EBUSY;
 220 }
 221 #else
 222 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
 223 {
 224         int minor;
 225
 226         switch (type) {
 227         case SNDRV_DEVICE_TYPE_SEQUENCER:
 228         case SNDRV_DEVICE_TYPE_TIMER:
 229                 minor = type;
 230                 break;
 231         case SNDRV_DEVICE_TYPE_CONTROL:
 232                 if (snd_BUG_ON(!card))
 233                         return -EINVAL;
 234                 minor = SNDRV_MINOR(card->number, type);
 235                 break;
 236         case SNDRV_DEVICE_TYPE_HWDEP:
 237         case SNDRV_DEVICE_TYPE_RAWMIDI:
 238         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 239         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 240         case SNDRV_DEVICE_TYPE_COMPRESS:
 241                 if (snd_BUG_ON(!card))
 242                         return -EINVAL;
 243                 minor = SNDRV_MINOR(card->number, type + dev);
 244                 break;
 245         default:
 246                 return -EINVAL;
 247         }
 248         if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
 249                 return -EINVAL;
 250         return minor;
 251 }
 252 #endif
 253
 254 /**
 255  * snd_register_device_for_dev - Register the ALSA device file for the card
 256  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 257  * @card: the card instance
 258  * @dev: the device index
 259  * @f_ops: the file operations
 260  * @private_data: user pointer for f_ops->open()
 261  * @name: the device file name
 262  * @device: the &struct device to link this new device to
 263  *
 264  * Registers an ALSA device file for the given card.
 265  * The operators have to be set in reg parameter.
 266  *
 267  * Return: Zero if successful, or a negative error code on failure.
 268  */
 269 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
 270                                 const struct file_operations *f_ops,
 271                                 void *private_data,
 272                                 const char *name, struct device *device)
 273 {
 274         int minor;
 275         struct snd_minor *preg;
 276
 277         if (snd_BUG_ON(!name))
 278                 return -EINVAL;
 279         preg = kmalloc(sizeof *preg, GFP_KERNEL);
 280         if (preg == NULL)
 281                 return -ENOMEM;
 282         preg->type = type;
 283         preg->card = card ? card->number : -1;
 284         preg->device = dev;
 285         preg->f_ops = f_ops;
 286         preg->private_data = private_data;
 287         preg->card_ptr = card;
 288         mutex_lock(&sound_mutex);
 289 #ifdef CONFIG_SND_DYNAMIC_MINORS
 290         minor = snd_find_free_minor(type);
 291 #else
 292         minor = snd_kernel_minor(type, card, dev);
 293         if (minor >= 0 && snd_minors[minor])
 294                 minor = -EBUSY;
 295 #endif
 296         if (minor < 0) {
 297                 mutex_unlock(&sound_mutex);
 298                 kfree(preg);
 299                 return minor;
 300         }
 301         snd_minors[minor] = preg;
 302         preg->dev = device_create(sound_class, device, MKDEV(major, minor),
 303                                   private_data, "%s", name);
 304         if (IS_ERR(preg->dev)) {
 305                 snd_minors[minor] = NULL;
 306                 mutex_unlock(&sound_mutex);
 307                 minor = PTR_ERR(preg->dev);
 308                 kfree(preg);
 309                 return minor;
 310         }
 311
 312         mutex_unlock(&sound_mutex);
 313         return 0;
 314 }
 315
 316 EXPORT_SYMBOL(snd_register_device_for_dev);
 317
 318 /* find the matching minor record
 319  * return the index of snd_minor, or -1 if not found
 320  */
 321 static int find_snd_minor(int type, struct snd_card *card, int dev)
 322 {
 323         int cardnum, minor;
 324         struct snd_minor *mptr;
 325
 326         cardnum = card ? card->number : -1;
 327         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
 328                 if ((mptr = snd_minors[minor]) != NULL &&
 329                     mptr->type == type &&
 330                     mptr->card == cardnum &&
 331                     mptr->device == dev)
 332                         return minor;
 333         return -1;
 334 }
 335
 336 /**
 337  * snd_unregister_device - unregister the device on the given card
 338  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 339  * @card: the card instance
 340  * @dev: the device index
 341  *
 342  * Unregisters the device file already registered via
 343  * snd_register_device().
 344  *
 345  * Return: Zero if successful, or a negative error code on failure.
 346  */
 347 int snd_unregister_device(int type, struct snd_card *card, int dev)
 348 {
 349         int minor;
 350
 351         mutex_lock(&sound_mutex);
 352         minor = find_snd_minor(type, card, dev);
 353         if (minor < 0) {
 354                 mutex_unlock(&sound_mutex);
 355                 return -EINVAL;
 356         }
 357
 358         device_destroy(sound_class, MKDEV(major, minor));
 359
 360         kfree(snd_minors[minor]);
 361         snd_minors[minor] = NULL;
 362         mutex_unlock(&sound_mutex);
 363         return 0;
 364 }
 365
 366 EXPORT_SYMBOL(snd_unregister_device);
 367
 368 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
 369                               struct device_attribute *attr)
 370 {
 371         int minor, ret = -EINVAL;
 372         struct device *d;
 373
 374         mutex_lock(&sound_mutex);
 375         minor = find_snd_minor(type, card, dev);
 376         if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
 377                 ret = device_create_file(d, attr);
 378         mutex_unlock(&sound_mutex);
 379         return ret;
 380
 381 }
 382
 383 EXPORT_SYMBOL(snd_add_device_sysfs_file);
 384
 385 #ifdef CONFIG_PROC_FS
 386 /*
 387  *  INFO PART
 388  */
 389
 390 static struct snd_info_entry *snd_minor_info_entry;
 391
 392 static const char *snd_device_type_name(int type)
 393 {
 394         switch (type) {
 395         case SNDRV_DEVICE_TYPE_CONTROL:
 396                 return "control";
 397         case SNDRV_DEVICE_TYPE_HWDEP:
 398                 return "hardware dependent";
 399         case SNDRV_DEVICE_TYPE_RAWMIDI:
 400                 return "raw midi";
 401         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 402                 return "digital audio playback";
 403         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 404                 return "digital audio capture";
 405         case SNDRV_DEVICE_TYPE_SEQUENCER:
 406                 return "sequencer";
 407         case SNDRV_DEVICE_TYPE_TIMER:
 408                 return "timer";
 409         default:
 410                 return "?";
 411         }
 412 }
 413
 414 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 415 {
 416         int minor;
 417         struct snd_minor *mptr;
 418
 419         mutex_lock(&sound_mutex);
 420         for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
 421                 if (!(mptr = snd_minors[minor]))
 422                         continue;
 423                 if (mptr->card >= 0) {
 424                         if (mptr->device >= 0)
 425                                 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
 426                                             minor, mptr->card, mptr->device,
 427                                             snd_device_type_name(mptr->type));
 428                         else
 429                                 snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
 430                                             minor, mptr->card,
 431                                             snd_device_type_name(mptr->type));
 432                 } else
 433                         snd_iprintf(buffer, "%3i:        : %s\n", minor,
 434                                     snd_device_type_name(mptr->type));
 435         }
 436         mutex_unlock(&sound_mutex);
 437 }
 438
 439 int __init snd_minor_info_init(void)
 440 {
 441         struct snd_info_entry *entry;
 442
 443         entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
 444         if (entry) {
 445                 entry->c.text.read = snd_minor_info_read;
 446                 if (snd_info_register(entry) < 0) {
 447                         snd_info_free_entry(entry);
 448                         entry = NULL;
 449                 }
 450         }
 451         snd_minor_info_entry = entry;
 452         return 0;
 453 }
 454
 455 int __exit snd_minor_info_done(void)
 456 {
 457         snd_info_free_entry(snd_minor_info_entry);
 458         return 0;
 459 }
 460 #endif /* CONFIG_PROC_FS */
 461
 462 /*
 463  *  INIT PART
 464  */
 465
 466 static int __init alsa_sound_init(void)
 467 {
 468         snd_major = major;
 469         snd_ecards_limit = cards_limit;
 470         if (register_chrdev(major, "alsa", &snd_fops)) {
 471                 snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
 472                 return -EIO;
 473         }
 474         if (snd_info_init() < 0) {
 475                 unregister_chrdev(major, "alsa");
 476                 return -ENOMEM;
 477         }
 478         snd_info_minor_register();
 479 #ifndef MODULE
 480         printk(KERN_INFO "Advanced Linux Sound Architecture Driver Initialized.\n");
 481 #endif
 482         return 0;
 483 }
 484
 485 static void __exit alsa_sound_exit(void)
 486 {
 487         snd_info_minor_unregister();
 488         snd_info_done();
 489         unregister_chrdev(major, "alsa");
 490 }
 491
 492 subsys_initcall(alsa_sound_init);
 493 module_exit(alsa_sound_exit);