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, struct snd_card *card, int dev)
 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_find_free_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         if (snd_minors[minor])
 241                 return -EBUSY;
 242         return minor;
 243 }
 244 #endif
 245
 246 /**
 247  * snd_register_device - 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  * @device: the device to register
 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(int type, struct snd_card *card, int dev,
 261                         const struct file_operations *f_ops,
 262                         void *private_data, struct device *device)
 263 {
 264         int minor;
 265         int err = 0;
 266         struct snd_minor *preg;
 267
 268         if (snd_BUG_ON(!device))
 269                 return -EINVAL;
 270
 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         preg->card_ptr = card;
 280         mutex_lock(&sound_mutex);
 281         minor = snd_find_free_minor(type, card, dev);
 282         if (minor < 0) {
 283                 err = minor;
 284                 goto error;
 285         }
 286
 287         preg->dev = device;
 288         device->devt = MKDEV(major, minor);
 289         err = device_add(device);
 290         if (err < 0)
 291                 goto error;
 292
 293         snd_minors[minor] = preg;
 294  error:
 295         mutex_unlock(&sound_mutex);
 296         if (err < 0)
 297                 kfree(preg);
 298         return err;
 299 }
 300 EXPORT_SYMBOL(snd_register_device);
 301
 302 /**
 303  * snd_unregister_device - unregister the device on the given card
 304  * @dev: the device instance
 305  *
 306  * Unregisters the device file already registered via
 307  * snd_register_device().
 308  *
 309  * Return: Zero if successful, or a negative error code on failure.
 310  */
 311 int snd_unregister_device(struct device *dev)
 312 {
 313         int minor;
 314         struct snd_minor *preg;
 315
 316         mutex_lock(&sound_mutex);
 317         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
 318                 preg = snd_minors[minor];
 319                 if (preg && preg->dev == dev) {
 320                         snd_minors[minor] = NULL;
 321                         device_del(dev);
 322                         kfree(preg);
 323                         break;
 324                 }
 325         }
 326         mutex_unlock(&sound_mutex);
 327         if (minor >= ARRAY_SIZE(snd_minors))
 328                 return -ENOENT;
 329         return 0;
 330 }
 331 EXPORT_SYMBOL(snd_unregister_device);
 332
 333 #ifdef CONFIG_SND_PROC_FS
 334 /*
 335  *  INFO PART
 336  */
 337 static const char *snd_device_type_name(int type)
 338 {
 339         switch (type) {
 340         case SNDRV_DEVICE_TYPE_CONTROL:
 341                 return "control";
 342         case SNDRV_DEVICE_TYPE_HWDEP:
 343                 return "hardware dependent";
 344         case SNDRV_DEVICE_TYPE_RAWMIDI:
 345                 return "raw midi";
 346         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 347                 return "digital audio playback";
 348         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 349                 return "digital audio capture";
 350         case SNDRV_DEVICE_TYPE_SEQUENCER:
 351                 return "sequencer";
 352         case SNDRV_DEVICE_TYPE_TIMER:
 353                 return "timer";
 354         default:
 355                 return "?";
 356         }
 357 }
 358
 359 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 360 {
 361         int minor;
 362         struct snd_minor *mptr;
 363
 364         mutex_lock(&sound_mutex);
 365         for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
 366                 if (!(mptr = snd_minors[minor]))
 367                         continue;
 368                 if (mptr->card >= 0) {
 369                         if (mptr->device >= 0)
 370                                 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
 371                                             minor, mptr->card, mptr->device,
 372                                             snd_device_type_name(mptr->type));
 373                         else
 374                                 snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
 375                                             minor, mptr->card,
 376                                             snd_device_type_name(mptr->type));
 377                 } else
 378                         snd_iprintf(buffer, "%3i:        : %s\n", minor,
 379                                     snd_device_type_name(mptr->type));
 380         }
 381         mutex_unlock(&sound_mutex);
 382 }
 383
 384 int __init snd_minor_info_init(void)
 385 {
 386         struct snd_info_entry *entry;
 387
 388         entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
 389         if (!entry)
 390                 return -ENOMEM;
 391         entry->c.text.read = snd_minor_info_read;
 392         return snd_info_register(entry); /* freed in error path */
 393 }
 394 #endif /* CONFIG_SND_PROC_FS */
 395
 396 /*
 397  *  INIT PART
 398  */
 399
 400 static int __init alsa_sound_init(void)
 401 {
 402         snd_major = major;
 403         snd_ecards_limit = cards_limit;
 404         if (register_chrdev(major, "alsa", &snd_fops)) {
 405                 pr_err("ALSA core: unable to register native major device number %d\n", major);
 406                 return -EIO;
 407         }
 408         if (snd_info_init() < 0) {
 409                 unregister_chrdev(major, "alsa");
 410                 return -ENOMEM;
 411         }
 412 #ifndef MODULE
 413         pr_info("Advanced Linux Sound Architecture Driver Initialized.\n");
 414 #endif
 415         return 0;
 416 }
 417
 418 static void __exit alsa_sound_exit(void)
 419 {
 420         snd_info_done();
 421         unregister_chrdev(major, "alsa");
 422 }
 423
 424 subsys_initcall(alsa_sound_init);
 425 module_exit(alsa_sound_exit);