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