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/smp_lock.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@perex.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 #ifdef CONFIG_MODULES
  65
  66 /**
  67  * snd_request_card - try to load the card module
  68  * @card: the card number
  69  *
  70  * Tries to load the module "snd-card-X" for the given card number
  71  * via request_module.  Returns immediately if already loaded.
  72  */
  73 void snd_request_card(int card)
  74 {
  75         if (snd_card_locked(card))
  76                 return;
  77         if (card < 0 || card >= cards_limit)
  78                 return;
  79         request_module("snd-card-%i", card);
  80 }
  81
  82 EXPORT_SYMBOL(snd_request_card);
  83
  84 static void snd_request_other(int minor)
  85 {
  86         char *str;
  87
  88         switch (minor) {
  89         case SNDRV_MINOR_SEQUENCER:     str = "snd-seq";        break;
  90         case SNDRV_MINOR_TIMER:         str = "snd-timer";      break;
  91         default:                        return;
  92         }
  93         request_module(str);
  94 }
  95
  96 #endif  /* modular kernel */
  97
  98 /**
  99  * snd_lookup_minor_data - get user data of a registered device
 100  * @minor: the minor number
 101  * @type: device type (SNDRV_DEVICE_TYPE_XXX)
 102  *
 103  * Checks that a minor device with the specified type is registered, and returns
 104  * its user data pointer.
 105  */
 106 void *snd_lookup_minor_data(unsigned int minor, int type)
 107 {
 108         struct snd_minor *mreg;
 109         void *private_data;
 110
 111         if (minor >= ARRAY_SIZE(snd_minors))
 112                 return NULL;
 113         mutex_lock(&sound_mutex);
 114         mreg = snd_minors[minor];
 115         if (mreg && mreg->type == type)
 116                 private_data = mreg->private_data;
 117         else
 118                 private_data = NULL;
 119         mutex_unlock(&sound_mutex);
 120         return private_data;
 121 }
 122
 123 EXPORT_SYMBOL(snd_lookup_minor_data);
 124
 125 static int __snd_open(struct inode *inode, struct file *file)
 126 {
 127         unsigned int minor = iminor(inode);
 128         struct snd_minor *mptr = NULL;
 129         const struct file_operations *old_fops;
 130         int err = 0;
 131
 132         if (minor >= ARRAY_SIZE(snd_minors))
 133                 return -ENODEV;
 134         mptr = snd_minors[minor];
 135         if (mptr == NULL) {
 136 #ifdef CONFIG_MODULES
 137                 int dev = SNDRV_MINOR_DEVICE(minor);
 138                 if (dev == SNDRV_MINOR_CONTROL) {
 139                         /* /dev/aloadC? */
 140                         int card = SNDRV_MINOR_CARD(minor);
 141                         if (snd_cards[card] == NULL)
 142                                 snd_request_card(card);
 143                 } else if (dev == SNDRV_MINOR_GLOBAL) {
 144                         /* /dev/aloadSEQ */
 145                         snd_request_other(minor);
 146                 }
 147 #ifndef CONFIG_SND_DYNAMIC_MINORS
 148                 /* /dev/snd/{controlC?,seq} */
 149                 mptr = snd_minors[minor];
 150                 if (mptr == NULL)
 151 #endif
 152 #endif
 153                         return -ENODEV;
 154         }
 155         old_fops = file->f_op;
 156         file->f_op = fops_get(mptr->f_ops);
 157         if (file->f_op->open)
 158                 err = file->f_op->open(inode, file);
 159         if (err) {
 160                 fops_put(file->f_op);
 161                 file->f_op = fops_get(old_fops);
 162         }
 163         fops_put(old_fops);
 164         return err;
 165 }
 166
 167
 168 /* BKL pushdown: nasty #ifdef avoidance wrapper */
 169 static int snd_open(struct inode *inode, struct file *file)
 170 {
 171         int ret;
 172
 173         lock_kernel();
 174         ret = __snd_open(inode, file);
 175         unlock_kernel();
 176         return ret;
 177 }
 178
 179 static const struct file_operations snd_fops =
 180 {
 181         .owner =        THIS_MODULE,
 182         .open =         snd_open
 183 };
 184
 185 #ifdef CONFIG_SND_DYNAMIC_MINORS
 186 static int snd_find_free_minor(void)
 187 {
 188         int minor;
 189
 190         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
 191                 /* skip minors still used statically for autoloading devices */
 192                 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL ||
 193                     minor == SNDRV_MINOR_SEQUENCER)
 194                         continue;
 195                 if (!snd_minors[minor])
 196                         return minor;
 197         }
 198         return -EBUSY;
 199 }
 200 #else
 201 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
 202 {
 203         int minor;
 204
 205         switch (type) {
 206         case SNDRV_DEVICE_TYPE_SEQUENCER:
 207         case SNDRV_DEVICE_TYPE_TIMER:
 208                 minor = type;
 209                 break;
 210         case SNDRV_DEVICE_TYPE_CONTROL:
 211                 snd_assert(card != NULL, return -EINVAL);
 212                 minor = SNDRV_MINOR(card->number, type);
 213                 break;
 214         case SNDRV_DEVICE_TYPE_HWDEP:
 215         case SNDRV_DEVICE_TYPE_RAWMIDI:
 216         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 217         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 218                 snd_assert(card != NULL, return -EINVAL);
 219                 minor = SNDRV_MINOR(card->number, type + dev);
 220                 break;
 221         default:
 222                 return -EINVAL;
 223         }
 224         snd_assert(minor >= 0 && minor < SNDRV_OS_MINORS, return -EINVAL);
 225         return minor;
 226 }
 227 #endif
 228
 229 /**
 230  * snd_register_device_for_dev - Register the ALSA device file for the card
 231  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 232  * @card: the card instance
 233  * @dev: the device index
 234  * @f_ops: the file operations
 235  * @private_data: user pointer for f_ops->open()
 236  * @name: the device file name
 237  * @device: the &struct device to link this new device to
 238  *
 239  * Registers an ALSA device file for the given card.
 240  * The operators have to be set in reg parameter.
 241  *
 242  * Returns zero if successful, or a negative error code on failure.
 243  */
 244 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
 245                                 const struct file_operations *f_ops,
 246                                 void *private_data,
 247                                 const char *name, struct device *device)
 248 {
 249         int minor;
 250         struct snd_minor *preg;
 251
 252         snd_assert(name, return -EINVAL);
 253         preg = kmalloc(sizeof *preg, GFP_KERNEL);
 254         if (preg == NULL)
 255                 return -ENOMEM;
 256         preg->type = type;
 257         preg->card = card ? card->number : -1;
 258         preg->device = dev;
 259         preg->f_ops = f_ops;
 260         preg->private_data = private_data;
 261         mutex_lock(&sound_mutex);
 262 #ifdef CONFIG_SND_DYNAMIC_MINORS
 263         minor = snd_find_free_minor();
 264 #else
 265         minor = snd_kernel_minor(type, card, dev);
 266         if (minor >= 0 && snd_minors[minor])
 267                 minor = -EBUSY;
 268 #endif
 269         if (minor < 0) {
 270                 mutex_unlock(&sound_mutex);
 271                 kfree(preg);
 272                 return minor;
 273         }
 274         snd_minors[minor] = preg;
 275         preg->dev = device_create_drvdata(sound_class, device,
 276                                           MKDEV(major, minor),
 277                                           private_data, "%s", name);
 278         if (IS_ERR(preg->dev)) {
 279                 snd_minors[minor] = NULL;
 280                 mutex_unlock(&sound_mutex);
 281                 minor = PTR_ERR(preg->dev);
 282                 kfree(preg);
 283                 return minor;
 284         }
 285
 286         mutex_unlock(&sound_mutex);
 287         return 0;
 288 }
 289
 290 EXPORT_SYMBOL(snd_register_device_for_dev);
 291
 292 /* find the matching minor record
 293  * return the index of snd_minor, or -1 if not found
 294  */
 295 static int find_snd_minor(int type, struct snd_card *card, int dev)
 296 {
 297         int cardnum, minor;
 298         struct snd_minor *mptr;
 299
 300         cardnum = card ? card->number : -1;
 301         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
 302                 if ((mptr = snd_minors[minor]) != NULL &&
 303                     mptr->type == type &&
 304                     mptr->card == cardnum &&
 305                     mptr->device == dev)
 306                         return minor;
 307         return -1;
 308 }
 309
 310 /**
 311  * snd_unregister_device - unregister the device on the given card
 312  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 313  * @card: the card instance
 314  * @dev: the device index
 315  *
 316  * Unregisters the device file already registered via
 317  * snd_register_device().
 318  *
 319  * Returns zero if sucecessful, or a negative error code on failure
 320  */
 321 int snd_unregister_device(int type, struct snd_card *card, int dev)
 322 {
 323         int minor;
 324
 325         mutex_lock(&sound_mutex);
 326         minor = find_snd_minor(type, card, dev);
 327         if (minor < 0) {
 328                 mutex_unlock(&sound_mutex);
 329                 return -EINVAL;
 330         }
 331
 332         device_destroy(sound_class, MKDEV(major, minor));
 333
 334         kfree(snd_minors[minor]);
 335         snd_minors[minor] = NULL;
 336         mutex_unlock(&sound_mutex);
 337         return 0;
 338 }
 339
 340 EXPORT_SYMBOL(snd_unregister_device);
 341
 342 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
 343                               struct device_attribute *attr)
 344 {
 345         int minor, ret = -EINVAL;
 346         struct device *d;
 347
 348         mutex_lock(&sound_mutex);
 349         minor = find_snd_minor(type, card, dev);
 350         if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
 351                 ret = device_create_file(d, attr);
 352         mutex_unlock(&sound_mutex);
 353         return ret;
 354
 355 }
 356
 357 EXPORT_SYMBOL(snd_add_device_sysfs_file);
 358
 359 #ifdef CONFIG_PROC_FS
 360 /*
 361  *  INFO PART
 362  */
 363
 364 static struct snd_info_entry *snd_minor_info_entry;
 365
 366 static const char *snd_device_type_name(int type)
 367 {
 368         switch (type) {
 369         case SNDRV_DEVICE_TYPE_CONTROL:
 370                 return "control";
 371         case SNDRV_DEVICE_TYPE_HWDEP:
 372                 return "hardware dependent";
 373         case SNDRV_DEVICE_TYPE_RAWMIDI:
 374                 return "raw midi";
 375         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 376                 return "digital audio playback";
 377         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 378                 return "digital audio capture";
 379         case SNDRV_DEVICE_TYPE_SEQUENCER:
 380                 return "sequencer";
 381         case SNDRV_DEVICE_TYPE_TIMER:
 382                 return "timer";
 383         default:
 384                 return "?";
 385         }
 386 }
 387
 388 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 389 {
 390         int minor;
 391         struct snd_minor *mptr;
 392
 393         mutex_lock(&sound_mutex);
 394         for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
 395                 if (!(mptr = snd_minors[minor]))
 396                         continue;
 397                 if (mptr->card >= 0) {
 398                         if (mptr->device >= 0)
 399                                 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
 400                                             minor, mptr->card, mptr->device,
 401                                             snd_device_type_name(mptr->type));
 402                         else
 403                                 snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
 404                                             minor, mptr->card,
 405                                             snd_device_type_name(mptr->type));
 406                 } else
 407                         snd_iprintf(buffer, "%3i:        : %s\n", minor,
 408                                     snd_device_type_name(mptr->type));
 409         }
 410         mutex_unlock(&sound_mutex);
 411 }
 412
 413 int __init snd_minor_info_init(void)
 414 {
 415         struct snd_info_entry *entry;
 416
 417         entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
 418         if (entry) {
 419                 entry->c.text.read = snd_minor_info_read;
 420                 if (snd_info_register(entry) < 0) {
 421                         snd_info_free_entry(entry);
 422                         entry = NULL;
 423                 }
 424         }
 425         snd_minor_info_entry = entry;
 426         return 0;
 427 }
 428
 429 int __exit snd_minor_info_done(void)
 430 {
 431         snd_info_free_entry(snd_minor_info_entry);
 432         return 0;
 433 }
 434 #endif /* CONFIG_PROC_FS */
 435
 436 /*
 437  *  INIT PART
 438  */
 439
 440 static int __init alsa_sound_init(void)
 441 {
 442         snd_major = major;
 443         snd_ecards_limit = cards_limit;
 444         if (register_chrdev(major, "alsa", &snd_fops)) {
 445                 snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
 446                 return -EIO;
 447         }
 448         if (snd_info_init() < 0) {
 449                 unregister_chrdev(major, "alsa");
 450                 return -ENOMEM;
 451         }
 452         snd_info_minor_register();
 453 #ifndef MODULE
 454         printk(KERN_INFO "Advanced Linux Sound Architecture Driver Version " CONFIG_SND_VERSION CONFIG_SND_DATE ".\n");
 455 #endif
 456         return 0;
 457 }
 458
 459 static void __exit alsa_sound_exit(void)
 460 {
 461         snd_info_minor_unregister();
 462         snd_info_done();
 463         unregister_chrdev(major, "alsa");
 464 }
 465
 466 module_init(alsa_sound_init)
 467 module_exit(alsa_sound_exit)