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 EXPORT_SYMBOL(snd_request_card);
  78
  79 static void snd_request_other(int minor)
  80 {
  81         char *str;
  82
  83         switch (minor) {
  84         case SNDRV_MINOR_SEQUENCER:     str = "snd-seq";        break;
  85         case SNDRV_MINOR_TIMER:         str = "snd-timer";      break;
  86         default:                        return;
  87         }
  88         request_module(str);
  89 }
  90
  91 #endif  /* modular kernel */
  92
  93 /**
  94  * snd_lookup_minor_data - get user data of a registered device
  95  * @minor: the minor number
  96  * @type: device type (SNDRV_DEVICE_TYPE_XXX)
  97  *
  98  * Checks that a minor device with the specified type is registered, and returns
  99  * its user data pointer.
 100  *
 101  * This function increments the reference counter of the card instance
 102  * if an associated instance with the given minor number and type is found.
 103  * The caller must call snd_card_unref() appropriately later.
 104  *
 105  * Return: The user data pointer if the specified device is found. %NULL
 106  * otherwise.
 107  */
 108 void *snd_lookup_minor_data(unsigned int minor, int type)
 109 {
 110         struct snd_minor *mreg;
 111         void *private_data;
 112
 113         if (minor >= ARRAY_SIZE(snd_minors))
 114                 return NULL;
 115         mutex_lock(&sound_mutex);
 116         mreg = snd_minors[minor];
 117         if (mreg && mreg->type == type) {
 118                 private_data = mreg->private_data;
 119                 if (private_data && mreg->card_ptr)
 120                         get_device(&mreg->card_ptr->card_dev);
 121         } else
 122                 private_data = NULL;
 123         mutex_unlock(&sound_mutex);
 124         return private_data;
 125 }
 126 EXPORT_SYMBOL(snd_lookup_minor_data);
 127
 128 #ifdef CONFIG_MODULES
 129 static struct snd_minor *autoload_device(unsigned int minor)
 130 {
 131         int dev;
 132         mutex_unlock(&sound_mutex); /* release lock temporarily */
 133         dev = SNDRV_MINOR_DEVICE(minor);
 134         if (dev == SNDRV_MINOR_CONTROL) {
 135                 /* /dev/aloadC? */
 136                 int card = SNDRV_MINOR_CARD(minor);
 137                 if (snd_cards[card] == NULL)
 138                         snd_request_card(card);
 139         } else if (dev == SNDRV_MINOR_GLOBAL) {
 140                 /* /dev/aloadSEQ */
 141                 snd_request_other(minor);
 142         }
 143         mutex_lock(&sound_mutex); /* reacuire lock */
 144         return snd_minors[minor];
 145 }
 146 #else /* !CONFIG_MODULES */
 147 #define autoload_device(minor)  NULL
 148 #endif /* CONFIG_MODULES */
 149
 150 static int snd_open(struct inode *inode, struct file *file)
 151 {
 152         unsigned int minor = iminor(inode);
 153         struct snd_minor *mptr = NULL;
 154         const struct file_operations *new_fops;
 155         int err = 0;
 156
 157         if (minor >= ARRAY_SIZE(snd_minors))
 158                 return -ENODEV;
 159         mutex_lock(&sound_mutex);
 160         mptr = snd_minors[minor];
 161         if (mptr == NULL) {
 162                 mptr = autoload_device(minor);
 163                 if (!mptr) {
 164                         mutex_unlock(&sound_mutex);
 165                         return -ENODEV;
 166                 }
 167         }
 168         new_fops = fops_get(mptr->f_ops);
 169         mutex_unlock(&sound_mutex);
 170         if (!new_fops)
 171                 return -ENODEV;
 172         replace_fops(file, new_fops);
 173
 174         if (file->f_op->open)
 175                 err = file->f_op->open(inode, file);
 176         return err;
 177 }
 178
 179 static const struct file_operations snd_fops =
 180 {
 181         .owner =        THIS_MODULE,
 182         .open =         snd_open,
 183         .llseek =       noop_llseek,
 184 };
 185
 186 #ifdef CONFIG_SND_DYNAMIC_MINORS
 187 static int snd_find_free_minor(int type, struct snd_card *card, int dev)
 188 {
 189         int minor;
 190
 191         /* static minors for module auto loading */
 192         if (type == SNDRV_DEVICE_TYPE_SEQUENCER)
 193                 return SNDRV_MINOR_SEQUENCER;
 194         if (type == SNDRV_DEVICE_TYPE_TIMER)
 195                 return SNDRV_MINOR_TIMER;
 196
 197         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
 198                 /* skip static minors still used for module auto loading */
 199                 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL)
 200                         continue;
 201                 if (minor == SNDRV_MINOR_SEQUENCER ||
 202                     minor == SNDRV_MINOR_TIMER)
 203                         continue;
 204                 if (!snd_minors[minor])
 205                         return minor;
 206         }
 207         return -EBUSY;
 208 }
 209 #else
 210 static int snd_find_free_minor(int type, struct snd_card *card, int dev)
 211 {
 212         int minor;
 213
 214         switch (type) {
 215         case SNDRV_DEVICE_TYPE_SEQUENCER:
 216         case SNDRV_DEVICE_TYPE_TIMER:
 217                 minor = type;
 218                 break;
 219         case SNDRV_DEVICE_TYPE_CONTROL:
 220                 if (snd_BUG_ON(!card))
 221                         return -EINVAL;
 222                 minor = SNDRV_MINOR(card->number, type);
 223                 break;
 224         case SNDRV_DEVICE_TYPE_HWDEP:
 225         case SNDRV_DEVICE_TYPE_RAWMIDI:
 226         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 227         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 228         case SNDRV_DEVICE_TYPE_COMPRESS:
 229                 if (snd_BUG_ON(!card))
 230                         return -EINVAL;
 231                 minor = SNDRV_MINOR(card->number, type + dev);
 232                 break;
 233         default:
 234                 return -EINVAL;
 235         }
 236         if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
 237                 return -EINVAL;
 238         if (snd_minors[minor])
 239                 return -EBUSY;
 240         return minor;
 241 }
 242 #endif
 243
 244 /**
 245  * snd_register_device - 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
 252  *
 253  * Registers an ALSA device file for the given card.
 254  * The operators have to be set in reg parameter.
 255  *
 256  * Return: Zero if successful, or a negative error code on failure.
 257  */
 258 int snd_register_device(int type, struct snd_card *card, int dev,
 259                         const struct file_operations *f_ops,
 260                         void *private_data, struct device *device)
 261 {
 262         int minor;
 263         int err = 0;
 264         struct snd_minor *preg;
 265
 266         if (snd_BUG_ON(!device))
 267                 return -EINVAL;
 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         minor = snd_find_free_minor(type, card, dev);
 280         if (minor < 0) {
 281                 err = minor;
 282                 goto error;
 283         }
 284
 285         preg->dev = device;
 286         device->devt = MKDEV(major, minor);
 287         err = device_add(device);
 288         if (err < 0)
 289                 goto error;
 290
 291         snd_minors[minor] = preg;
 292  error:
 293         mutex_unlock(&sound_mutex);
 294         if (err < 0)
 295                 kfree(preg);
 296         return err;
 297 }
 298 EXPORT_SYMBOL(snd_register_device);
 299
 300 /**
 301  * snd_unregister_device - unregister the device on the given card
 302  * @dev: the device instance
 303  *
 304  * Unregisters the device file already registered via
 305  * snd_register_device().
 306  *
 307  * Return: Zero if successful, or a negative error code on failure.
 308  */
 309 int snd_unregister_device(struct device *dev)
 310 {
 311         int minor;
 312         struct snd_minor *preg;
 313
 314         mutex_lock(&sound_mutex);
 315         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
 316                 preg = snd_minors[minor];
 317                 if (preg && preg->dev == dev) {
 318                         snd_minors[minor] = NULL;
 319                         device_del(dev);
 320                         kfree(preg);
 321                         break;
 322                 }
 323         }
 324         mutex_unlock(&sound_mutex);
 325         if (minor >= ARRAY_SIZE(snd_minors))
 326                 return -ENOENT;
 327         return 0;
 328 }
 329 EXPORT_SYMBOL(snd_unregister_device);
 330
 331 #ifdef CONFIG_SND_PROC_FS
 332 /*
 333  *  INFO PART
 334  */
 335 static const char *snd_device_type_name(int type)
 336 {
 337         switch (type) {
 338         case SNDRV_DEVICE_TYPE_CONTROL:
 339                 return "control";
 340         case SNDRV_DEVICE_TYPE_HWDEP:
 341                 return "hardware dependent";
 342         case SNDRV_DEVICE_TYPE_RAWMIDI:
 343                 return "raw midi";
 344         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 345                 return "digital audio playback";
 346         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 347                 return "digital audio capture";
 348         case SNDRV_DEVICE_TYPE_SEQUENCER:
 349                 return "sequencer";
 350         case SNDRV_DEVICE_TYPE_TIMER:
 351                 return "timer";
 352         default:
 353                 return "?";
 354         }
 355 }
 356
 357 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 358 {
 359         int minor;
 360         struct snd_minor *mptr;
 361
 362         mutex_lock(&sound_mutex);
 363         for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
 364                 if (!(mptr = snd_minors[minor]))
 365                         continue;
 366                 if (mptr->card >= 0) {
 367                         if (mptr->device >= 0)
 368                                 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
 369                                             minor, mptr->card, mptr->device,
 370                                             snd_device_type_name(mptr->type));
 371                         else
 372                                 snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
 373                                             minor, mptr->card,
 374                                             snd_device_type_name(mptr->type));
 375                 } else
 376                         snd_iprintf(buffer, "%3i:        : %s\n", minor,
 377                                     snd_device_type_name(mptr->type));
 378         }
 379         mutex_unlock(&sound_mutex);
 380 }
 381
 382 int __init snd_minor_info_init(void)
 383 {
 384         struct snd_info_entry *entry;
 385
 386         entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
 387         if (!entry)
 388                 return -ENOMEM;
 389         entry->c.text.read = snd_minor_info_read;
 390         return snd_info_register(entry); /* freed in error path */
 391 }
 392 #endif /* CONFIG_SND_PROC_FS */
 393
 394 /*
 395  *  INIT PART
 396  */
 397
 398 static int __init alsa_sound_init(void)
 399 {
 400         snd_major = major;
 401         snd_ecards_limit = cards_limit;
 402         if (register_chrdev(major, "alsa", &snd_fops)) {
 403                 pr_err("ALSA core: unable to register native major device number %d\n", major);
 404                 return -EIO;
 405         }
 406         if (snd_info_init() < 0) {
 407                 unregister_chrdev(major, "alsa");
 408                 return -ENOMEM;
 409         }
 410 #ifndef MODULE
 411         pr_info("Advanced Linux Sound Architecture Driver Initialized.\n");
 412 #endif
 413         return 0;
 414 }
 415
 416 static void __exit alsa_sound_exit(void)
 417 {
 418         snd_info_done();
 419         unregister_chrdev(major, "alsa");
 420 }
 421
 422 subsys_initcall(alsa_sound_init);
 423 module_exit(alsa_sound_exit);