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                         get_device(&mreg->card_ptr->card_dev);
 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 *new_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         new_fops = fops_get(mptr->f_ops);
 171         mutex_unlock(&sound_mutex);
 172         if (!new_fops)
 173                 return -ENODEV;
 174         replace_fops(file, new_fops);
 175
 176         if (file->f_op->open)
 177                 err = file->f_op->open(inode, file);
 178         return err;
 179 }
 180
 181 static const struct file_operations snd_fops =
 182 {
 183         .owner =        THIS_MODULE,
 184         .open =         snd_open,
 185         .llseek =       noop_llseek,
 186 };
 187
 188 #ifdef CONFIG_SND_DYNAMIC_MINORS
 189 static int snd_find_free_minor(int type)
 190 {
 191         int minor;
 192
 193         /* static minors for module auto loading */
 194         if (type == SNDRV_DEVICE_TYPE_SEQUENCER)
 195                 return SNDRV_MINOR_SEQUENCER;
 196         if (type == SNDRV_DEVICE_TYPE_TIMER)
 197                 return SNDRV_MINOR_TIMER;
 198
 199         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
 200                 /* skip static minors still used for module auto loading */
 201                 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL)
 202                         continue;
 203                 if (minor == SNDRV_MINOR_SEQUENCER ||
 204                     minor == SNDRV_MINOR_TIMER)
 205                         continue;
 206                 if (!snd_minors[minor])
 207                         return minor;
 208         }
 209         return -EBUSY;
 210 }
 211 #else
 212 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
 213 {
 214         int minor;
 215
 216         switch (type) {
 217         case SNDRV_DEVICE_TYPE_SEQUENCER:
 218         case SNDRV_DEVICE_TYPE_TIMER:
 219                 minor = type;
 220                 break;
 221         case SNDRV_DEVICE_TYPE_CONTROL:
 222                 if (snd_BUG_ON(!card))
 223                         return -EINVAL;
 224                 minor = SNDRV_MINOR(card->number, type);
 225                 break;
 226         case SNDRV_DEVICE_TYPE_HWDEP:
 227         case SNDRV_DEVICE_TYPE_RAWMIDI:
 228         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 229         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 230         case SNDRV_DEVICE_TYPE_COMPRESS:
 231                 if (snd_BUG_ON(!card))
 232                         return -EINVAL;
 233                 minor = SNDRV_MINOR(card->number, type + dev);
 234                 break;
 235         default:
 236                 return -EINVAL;
 237         }
 238         if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
 239                 return -EINVAL;
 240         return minor;
 241 }
 242 #endif
 243
 244 /**
 245  * snd_register_device_for_dev - Register the ALSA device file for the card
 246  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 247  * @card: the card instance
 248  * @dev: the device index
 249  * @f_ops: the file operations
 250  * @private_data: user pointer for f_ops->open()
 251  * @device: the device to register, NULL to create a new one
 252  * @parent: the &struct device to link this new device to (only for device=NULL)
 253  * @name: the device file name (only for device=NULL)
 254  *
 255  * Registers an ALSA device file for the given card.
 256  * The operators have to be set in reg parameter.
 257  *
 258  * Return: Zero if successful, or a negative error code on failure.
 259  */
 260 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
 261                                 const struct file_operations *f_ops,
 262                                 void *private_data, struct device *device,
 263                                 struct device *parent, const char *name)
 264 {
 265         int minor;
 266         int err = 0;
 267         struct snd_minor *preg;
 268
 269         preg = kmalloc(sizeof *preg, GFP_KERNEL);
 270         if (preg == NULL)
 271                 return -ENOMEM;
 272         preg->type = type;
 273         preg->card = card ? card->number : -1;
 274         preg->device = dev;
 275         preg->f_ops = f_ops;
 276         preg->private_data = private_data;
 277         preg->card_ptr = card;
 278         mutex_lock(&sound_mutex);
 279 #ifdef CONFIG_SND_DYNAMIC_MINORS
 280         minor = snd_find_free_minor(type);
 281 #else
 282         minor = snd_kernel_minor(type, card, dev);
 283         if (minor >= 0 && snd_minors[minor])
 284                 minor = -EBUSY;
 285 #endif
 286         if (minor < 0) {
 287                 err = minor;
 288                 goto error;
 289         }
 290
 291         if (device) {
 292                 preg->created = false;
 293                 preg->dev = device;
 294                 device->devt = MKDEV(major, minor);
 295                 err = device_add(device);
 296         } else {
 297                 preg->created = true;
 298                 preg->dev = device_create(sound_class, parent,
 299                                           MKDEV(major, minor), private_data,
 300                                           "%s", name);
 301                 if (IS_ERR(preg->dev))
 302                         err = PTR_ERR(preg->dev);
 303         }
 304         if (err < 0)
 305                 goto error;
 306
 307         snd_minors[minor] = preg;
 308  error:
 309         mutex_unlock(&sound_mutex);
 310         if (err < 0)
 311                 kfree(preg);
 312         return err;
 313 }
 314
 315 EXPORT_SYMBOL(snd_register_device_for_dev);
 316
 317 /* find the matching minor record
 318  * return the index of snd_minor, or -1 if not found
 319  */
 320 static int find_snd_minor(int type, struct snd_card *card, int dev)
 321 {
 322         int cardnum, minor;
 323         struct snd_minor *mptr;
 324
 325         cardnum = card ? card->number : -1;
 326         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
 327                 if ((mptr = snd_minors[minor]) != NULL &&
 328                     mptr->type == type &&
 329                     mptr->card == cardnum &&
 330                     mptr->device == dev)
 331                         return minor;
 332         return -1;
 333 }
 334
 335 /**
 336  * snd_unregister_device - unregister the device on the given card
 337  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 338  * @card: the card instance
 339  * @dev: the device index
 340  *
 341  * Unregisters the device file already registered via
 342  * snd_register_device().
 343  *
 344  * Return: Zero if successful, or a negative error code on failure.
 345  */
 346 int snd_unregister_device(int type, struct snd_card *card, int dev)
 347 {
 348         int minor;
 349         struct snd_minor *preg;
 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         preg = snd_minors[minor];
 359         if (preg && !preg->created)
 360                 device_del(preg->dev);
 361         else
 362                 device_destroy(sound_class, MKDEV(major, minor));
 363
 364         kfree(snd_minors[minor]);
 365         snd_minors[minor] = NULL;
 366         mutex_unlock(&sound_mutex);
 367         return 0;
 368 }
 369
 370 EXPORT_SYMBOL(snd_unregister_device);
 371
 372 /**
 373  * snd_get_device - get the assigned device to the given type and device number
 374  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 375  * @card:the card instance
 376  * @dev: the device index
 377  *
 378  * The caller needs to release it via put_device() after using it.
 379  */
 380 struct device *snd_get_device(int type, struct snd_card *card, int dev)
 381 {
 382         int minor;
 383         struct device *d = NULL;
 384
 385         mutex_lock(&sound_mutex);
 386         minor = find_snd_minor(type, card, dev);
 387         if (minor >= 0) {
 388                 d = snd_minors[minor]->dev;
 389                 if (d)
 390                         get_device(d);
 391         }
 392         mutex_unlock(&sound_mutex);
 393         return d;
 394 }
 395 EXPORT_SYMBOL(snd_get_device);
 396
 397 #ifdef CONFIG_PROC_FS
 398 /*
 399  *  INFO PART
 400  */
 401
 402 static struct snd_info_entry *snd_minor_info_entry;
 403
 404 static const char *snd_device_type_name(int type)
 405 {
 406         switch (type) {
 407         case SNDRV_DEVICE_TYPE_CONTROL:
 408                 return "control";
 409         case SNDRV_DEVICE_TYPE_HWDEP:
 410                 return "hardware dependent";
 411         case SNDRV_DEVICE_TYPE_RAWMIDI:
 412                 return "raw midi";
 413         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 414                 return "digital audio playback";
 415         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 416                 return "digital audio capture";
 417         case SNDRV_DEVICE_TYPE_SEQUENCER:
 418                 return "sequencer";
 419         case SNDRV_DEVICE_TYPE_TIMER:
 420                 return "timer";
 421         default:
 422                 return "?";
 423         }
 424 }
 425
 426 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 427 {
 428         int minor;
 429         struct snd_minor *mptr;
 430
 431         mutex_lock(&sound_mutex);
 432         for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
 433                 if (!(mptr = snd_minors[minor]))
 434                         continue;
 435                 if (mptr->card >= 0) {
 436                         if (mptr->device >= 0)
 437                                 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
 438                                             minor, mptr->card, mptr->device,
 439                                             snd_device_type_name(mptr->type));
 440                         else
 441                                 snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
 442                                             minor, mptr->card,
 443                                             snd_device_type_name(mptr->type));
 444                 } else
 445                         snd_iprintf(buffer, "%3i:        : %s\n", minor,
 446                                     snd_device_type_name(mptr->type));
 447         }
 448         mutex_unlock(&sound_mutex);
 449 }
 450
 451 int __init snd_minor_info_init(void)
 452 {
 453         struct snd_info_entry *entry;
 454
 455         entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
 456         if (entry) {
 457                 entry->c.text.read = snd_minor_info_read;
 458                 if (snd_info_register(entry) < 0) {
 459                         snd_info_free_entry(entry);
 460                         entry = NULL;
 461                 }
 462         }
 463         snd_minor_info_entry = entry;
 464         return 0;
 465 }
 466
 467 int __exit snd_minor_info_done(void)
 468 {
 469         snd_info_free_entry(snd_minor_info_entry);
 470         return 0;
 471 }
 472 #endif /* CONFIG_PROC_FS */
 473
 474 /*
 475  *  INIT PART
 476  */
 477
 478 static int __init alsa_sound_init(void)
 479 {
 480         snd_major = major;
 481         snd_ecards_limit = cards_limit;
 482         if (register_chrdev(major, "alsa", &snd_fops)) {
 483                 pr_err("ALSA core: unable to register native major device number %d\n", major);
 484                 return -EIO;
 485         }
 486         if (snd_info_init() < 0) {
 487                 unregister_chrdev(major, "alsa");
 488                 return -ENOMEM;
 489         }
 490         snd_info_minor_register();
 491 #ifndef MODULE
 492         pr_info("Advanced Linux Sound Architecture Driver Initialized.\n");
 493 #endif
 494         return 0;
 495 }
 496
 497 static void __exit alsa_sound_exit(void)
 498 {
 499         snd_info_minor_unregister();
 500         snd_info_done();
 501         unregister_chrdev(major, "alsa");
 502 }
 503
 504 subsys_initcall(alsa_sound_init);
 505 module_exit(alsa_sound_exit);