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/moduleparam.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(void)
 192 {
 193         int minor;
 194
 195         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
 196                 /* skip minors still used statically for autoloading devices */
 197                 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL ||
 198                     minor == SNDRV_MINOR_SEQUENCER)
 199                         continue;
 200                 if (!snd_minors[minor])
 201                         return minor;
 202         }
 203         return -EBUSY;
 204 }
 205 #else
 206 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
 207 {
 208         int minor;
 209
 210         switch (type) {
 211         case SNDRV_DEVICE_TYPE_SEQUENCER:
 212         case SNDRV_DEVICE_TYPE_TIMER:
 213                 minor = type;
 214                 break;
 215         case SNDRV_DEVICE_TYPE_CONTROL:
 216                 if (snd_BUG_ON(!card))
 217                         return -EINVAL;
 218                 minor = SNDRV_MINOR(card->number, type);
 219                 break;
 220         case SNDRV_DEVICE_TYPE_HWDEP:
 221         case SNDRV_DEVICE_TYPE_RAWMIDI:
 222         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 223         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 224                 if (snd_BUG_ON(!card))
 225                         return -EINVAL;
 226                 minor = SNDRV_MINOR(card->number, type + dev);
 227                 break;
 228         default:
 229                 return -EINVAL;
 230         }
 231         if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
 232                 return -EINVAL;
 233         return minor;
 234 }
 235 #endif
 236
 237 /**
 238  * snd_register_device_for_dev - Register the ALSA device file for the card
 239  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 240  * @card: the card instance
 241  * @dev: the device index
 242  * @f_ops: the file operations
 243  * @private_data: user pointer for f_ops->open()
 244  * @name: the device file name
 245  * @device: the &struct device to link this new device to
 246  *
 247  * Registers an ALSA device file for the given card.
 248  * The operators have to be set in reg parameter.
 249  *
 250  * Returns zero if successful, or a negative error code on failure.
 251  */
 252 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
 253                                 const struct file_operations *f_ops,
 254                                 void *private_data,
 255                                 const char *name, struct device *device)
 256 {
 257         int minor;
 258         struct snd_minor *preg;
 259
 260         if (snd_BUG_ON(!name))
 261                 return -EINVAL;
 262         preg = kmalloc(sizeof *preg, GFP_KERNEL);
 263         if (preg == NULL)
 264                 return -ENOMEM;
 265         preg->type = type;
 266         preg->card = card ? card->number : -1;
 267         preg->device = dev;
 268         preg->f_ops = f_ops;
 269         preg->private_data = private_data;
 270         mutex_lock(&sound_mutex);
 271 #ifdef CONFIG_SND_DYNAMIC_MINORS
 272         minor = snd_find_free_minor();
 273 #else
 274         minor = snd_kernel_minor(type, card, dev);
 275         if (minor >= 0 && snd_minors[minor])
 276                 minor = -EBUSY;
 277 #endif
 278         if (minor < 0) {
 279                 mutex_unlock(&sound_mutex);
 280                 kfree(preg);
 281                 return minor;
 282         }
 283         snd_minors[minor] = preg;
 284         preg->dev = device_create(sound_class, device, MKDEV(major, minor),
 285                                   private_data, "%s", name);
 286         if (IS_ERR(preg->dev)) {
 287                 snd_minors[minor] = NULL;
 288                 mutex_unlock(&sound_mutex);
 289                 minor = PTR_ERR(preg->dev);
 290                 kfree(preg);
 291                 return minor;
 292         }
 293
 294         mutex_unlock(&sound_mutex);
 295         return 0;
 296 }
 297
 298 EXPORT_SYMBOL(snd_register_device_for_dev);
 299
 300 /* find the matching minor record
 301  * return the index of snd_minor, or -1 if not found
 302  */
 303 static int find_snd_minor(int type, struct snd_card *card, int dev)
 304 {
 305         int cardnum, minor;
 306         struct snd_minor *mptr;
 307
 308         cardnum = card ? card->number : -1;
 309         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
 310                 if ((mptr = snd_minors[minor]) != NULL &&
 311                     mptr->type == type &&
 312                     mptr->card == cardnum &&
 313                     mptr->device == dev)
 314                         return minor;
 315         return -1;
 316 }
 317
 318 /**
 319  * snd_unregister_device - unregister the device on the given card
 320  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 321  * @card: the card instance
 322  * @dev: the device index
 323  *
 324  * Unregisters the device file already registered via
 325  * snd_register_device().
 326  *
 327  * Returns zero if sucecessful, or a negative error code on failure
 328  */
 329 int snd_unregister_device(int type, struct snd_card *card, int dev)
 330 {
 331         int minor;
 332
 333         mutex_lock(&sound_mutex);
 334         minor = find_snd_minor(type, card, dev);
 335         if (minor < 0) {
 336                 mutex_unlock(&sound_mutex);
 337                 return -EINVAL;
 338         }
 339
 340         device_destroy(sound_class, MKDEV(major, minor));
 341
 342         kfree(snd_minors[minor]);
 343         snd_minors[minor] = NULL;
 344         mutex_unlock(&sound_mutex);
 345         return 0;
 346 }
 347
 348 EXPORT_SYMBOL(snd_unregister_device);
 349
 350 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
 351                               struct device_attribute *attr)
 352 {
 353         int minor, ret = -EINVAL;
 354         struct device *d;
 355
 356         mutex_lock(&sound_mutex);
 357         minor = find_snd_minor(type, card, dev);
 358         if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
 359                 ret = device_create_file(d, attr);
 360         mutex_unlock(&sound_mutex);
 361         return ret;
 362
 363 }
 364
 365 EXPORT_SYMBOL(snd_add_device_sysfs_file);
 366
 367 #ifdef CONFIG_PROC_FS
 368 /*
 369  *  INFO PART
 370  */
 371
 372 static struct snd_info_entry *snd_minor_info_entry;
 373
 374 static const char *snd_device_type_name(int type)
 375 {
 376         switch (type) {
 377         case SNDRV_DEVICE_TYPE_CONTROL:
 378                 return "control";
 379         case SNDRV_DEVICE_TYPE_HWDEP:
 380                 return "hardware dependent";
 381         case SNDRV_DEVICE_TYPE_RAWMIDI:
 382                 return "raw midi";
 383         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 384                 return "digital audio playback";
 385         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 386                 return "digital audio capture";
 387         case SNDRV_DEVICE_TYPE_SEQUENCER:
 388                 return "sequencer";
 389         case SNDRV_DEVICE_TYPE_TIMER:
 390                 return "timer";
 391         default:
 392                 return "?";
 393         }
 394 }
 395
 396 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 397 {
 398         int minor;
 399         struct snd_minor *mptr;
 400
 401         mutex_lock(&sound_mutex);
 402         for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
 403                 if (!(mptr = snd_minors[minor]))
 404                         continue;
 405                 if (mptr->card >= 0) {
 406                         if (mptr->device >= 0)
 407                                 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
 408                                             minor, mptr->card, mptr->device,
 409                                             snd_device_type_name(mptr->type));
 410                         else
 411                                 snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
 412                                             minor, mptr->card,
 413                                             snd_device_type_name(mptr->type));
 414                 } else
 415                         snd_iprintf(buffer, "%3i:        : %s\n", minor,
 416                                     snd_device_type_name(mptr->type));
 417         }
 418         mutex_unlock(&sound_mutex);
 419 }
 420
 421 int __init snd_minor_info_init(void)
 422 {
 423         struct snd_info_entry *entry;
 424
 425         entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
 426         if (entry) {
 427                 entry->c.text.read = snd_minor_info_read;
 428                 if (snd_info_register(entry) < 0) {
 429                         snd_info_free_entry(entry);
 430                         entry = NULL;
 431                 }
 432         }
 433         snd_minor_info_entry = entry;
 434         return 0;
 435 }
 436
 437 int __exit snd_minor_info_done(void)
 438 {
 439         snd_info_free_entry(snd_minor_info_entry);
 440         return 0;
 441 }
 442 #endif /* CONFIG_PROC_FS */
 443
 444 /*
 445  *  INIT PART
 446  */
 447
 448 static int __init alsa_sound_init(void)
 449 {
 450         snd_major = major;
 451         snd_ecards_limit = cards_limit;
 452         if (register_chrdev(major, "alsa", &snd_fops)) {
 453                 snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
 454                 return -EIO;
 455         }
 456         if (snd_info_init() < 0) {
 457                 unregister_chrdev(major, "alsa");
 458                 return -ENOMEM;
 459         }
 460         snd_info_minor_register();
 461 #ifndef MODULE
 462         printk(KERN_INFO "Advanced Linux Sound Architecture Driver Version " CONFIG_SND_VERSION CONFIG_SND_DATE ".\n");
 463 #endif
 464         return 0;
 465 }
 466
 467 static void __exit alsa_sound_exit(void)
 468 {
 469         snd_info_minor_unregister();
 470         snd_info_done();
 471         unregister_chrdev(major, "alsa");
 472 }
 473
 474 subsys_initcall(alsa_sound_init);
 475 module_exit(alsa_sound_exit);