sound/core/sound.c

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