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 static int major = CONFIG_SND_MAJOR;
  38 int snd_major;
  39 EXPORT_SYMBOL(snd_major);
  40
  41 static int cards_limit = 1;
  42
  43 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
  44 MODULE_DESCRIPTION("Advanced Linux Sound Architecture driver for soundcards.");
  45 MODULE_LICENSE("GPL");
  46 module_param(major, int, 0444);
  47 MODULE_PARM_DESC(major, "Major # for sound driver.");
  48 module_param(cards_limit, int, 0444);
  49 MODULE_PARM_DESC(cards_limit, "Count of auto-loadable soundcards.");
  50 MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR);
  51
  52 /* this one holds the actual max. card number currently available.
  53  * as default, it's identical with cards_limit option.  when more
  54  * modules are loaded manually, this limit number increases, too.
  55  */
  56 int snd_ecards_limit;
  57 EXPORT_SYMBOL(snd_ecards_limit);
  58
  59 static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
  60 static DEFINE_MUTEX(sound_mutex);
  61
  62 #ifdef CONFIG_MODULES
  63
  64 /**
  65  * snd_request_card - try to load the card module
  66  * @card: the card number
  67  *
  68  * Tries to load the module "snd-card-X" for the given card number
  69  * via request_module.  Returns immediately if already loaded.
  70  */
  71 void snd_request_card(int card)
  72 {
  73         if (snd_card_locked(card))
  74                 return;
  75         if (card < 0 || card >= cards_limit)
  76                 return;
  77         request_module("snd-card-%i", card);
  78 }
  79
  80 EXPORT_SYMBOL(snd_request_card);
  81
  82 static void snd_request_other(int minor)
  83 {
  84         char *str;
  85
  86         switch (minor) {
  87         case SNDRV_MINOR_SEQUENCER:     str = "snd-seq";        break;
  88         case SNDRV_MINOR_TIMER:         str = "snd-timer";      break;
  89         default:                        return;
  90         }
  91         request_module(str);
  92 }
  93
  94 #endif  /* modular kernel */
  95
  96 /**
  97  * snd_lookup_minor_data - get user data of a registered device
  98  * @minor: the minor number
  99  * @type: device type (SNDRV_DEVICE_TYPE_XXX)
 100  *
 101  * Checks that a minor device with the specified type is registered, and returns
 102  * its user data pointer.
 103  */
 104 void *snd_lookup_minor_data(unsigned int minor, int type)
 105 {
 106         struct snd_minor *mreg;
 107         void *private_data;
 108
 109         if (minor >= ARRAY_SIZE(snd_minors))
 110                 return NULL;
 111         mutex_lock(&sound_mutex);
 112         mreg = snd_minors[minor];
 113         if (mreg && mreg->type == type)
 114                 private_data = mreg->private_data;
 115         else
 116                 private_data = NULL;
 117         mutex_unlock(&sound_mutex);
 118         return private_data;
 119 }
 120
 121 EXPORT_SYMBOL(snd_lookup_minor_data);
 122
 123 #ifdef CONFIG_MODULES
 124 static struct snd_minor *autoload_device(unsigned int minor)
 125 {
 126         int dev;
 127         mutex_unlock(&sound_mutex); /* release lock temporarily */
 128         dev = SNDRV_MINOR_DEVICE(minor);
 129         if (dev == SNDRV_MINOR_CONTROL) {
 130                 /* /dev/aloadC? */
 131                 int card = SNDRV_MINOR_CARD(minor);
 132                 if (snd_cards[card] == NULL)
 133                         snd_request_card(card);
 134         } else if (dev == SNDRV_MINOR_GLOBAL) {
 135                 /* /dev/aloadSEQ */
 136                 snd_request_other(minor);
 137         }
 138         mutex_lock(&sound_mutex); /* reacuire lock */
 139         return snd_minors[minor];
 140 }
 141 #else /* !CONFIG_MODULES */
 142 #define autoload_device(minor)  NULL
 143 #endif /* CONFIG_MODULES */
 144
 145 static int snd_open(struct inode *inode, struct file *file)
 146 {
 147         unsigned int minor = iminor(inode);
 148         struct snd_minor *mptr = NULL;
 149         const struct file_operations *old_fops;
 150         int err = 0;
 151
 152         if (minor >= ARRAY_SIZE(snd_minors))
 153                 return -ENODEV;
 154         mutex_lock(&sound_mutex);
 155         mptr = snd_minors[minor];
 156         if (mptr == NULL) {
 157                 mptr = autoload_device(minor);
 158                 if (!mptr) {
 159                         mutex_unlock(&sound_mutex);
 160                         return -ENODEV;
 161                 }
 162         }
 163         old_fops = file->f_op;
 164         file->f_op = fops_get(mptr->f_ops);
 165         if (file->f_op == NULL) {
 166                 file->f_op = old_fops;
 167                 err = -ENODEV;
 168         }
 169         mutex_unlock(&sound_mutex);
 170         if (err < 0)
 171                 return err;
 172
 173         if (file->f_op->open) {
 174                 err = file->f_op->open(inode, file);
 175                 if (err) {
 176                         fops_put(file->f_op);
 177                         file->f_op = fops_get(old_fops);
 178                 }
 179         }
 180         fops_put(old_fops);
 181         return err;
 182 }
 183
 184 static const struct file_operations snd_fops =
 185 {
 186         .owner =        THIS_MODULE,
 187         .open =         snd_open,
 188         .llseek =       noop_llseek,
 189 };
 190
 191 #ifdef CONFIG_SND_DYNAMIC_MINORS
 192 static int snd_find_free_minor(void)
 193 {
 194         int minor;
 195
 196         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
 197                 /* skip minors still used statically for autoloading devices */
 198                 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL ||
 199                     minor == SNDRV_MINOR_SEQUENCER)
 200                         continue;
 201                 if (!snd_minors[minor])
 202                         return minor;
 203         }
 204         return -EBUSY;
 205 }
 206 #else
 207 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
 208 {
 209         int minor;
 210
 211         switch (type) {
 212         case SNDRV_DEVICE_TYPE_SEQUENCER:
 213         case SNDRV_DEVICE_TYPE_TIMER:
 214                 minor = type;
 215                 break;
 216         case SNDRV_DEVICE_TYPE_CONTROL:
 217                 if (snd_BUG_ON(!card))
 218                         return -EINVAL;
 219                 minor = SNDRV_MINOR(card->number, type);
 220                 break;
 221         case SNDRV_DEVICE_TYPE_HWDEP:
 222         case SNDRV_DEVICE_TYPE_RAWMIDI:
 223         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 224         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 225                 if (snd_BUG_ON(!card))
 226                         return -EINVAL;
 227                 minor = SNDRV_MINOR(card->number, type + dev);
 228                 break;
 229         default:
 230                 return -EINVAL;
 231         }
 232         if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
 233                 return -EINVAL;
 234         return minor;
 235 }
 236 #endif
 237
 238 /**
 239  * snd_register_device_for_dev - Register the ALSA device file for the card
 240  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 241  * @card: the card instance
 242  * @dev: the device index
 243  * @f_ops: the file operations
 244  * @private_data: user pointer for f_ops->open()
 245  * @name: the device file name
 246  * @device: the &struct device to link this new device to
 247  *
 248  * Registers an ALSA device file for the given card.
 249  * The operators have to be set in reg parameter.
 250  *
 251  * Returns zero if successful, or a negative error code on failure.
 252  */
 253 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
 254                                 const struct file_operations *f_ops,
 255                                 void *private_data,
 256                                 const char *name, struct device *device)
 257 {
 258         int minor;
 259         struct snd_minor *preg;
 260
 261         if (snd_BUG_ON(!name))
 262                 return -EINVAL;
 263         preg = kmalloc(sizeof *preg, GFP_KERNEL);
 264         if (preg == NULL)
 265                 return -ENOMEM;
 266         preg->type = type;
 267         preg->card = card ? card->number : -1;
 268         preg->device = dev;
 269         preg->f_ops = f_ops;
 270         preg->private_data = private_data;
 271         mutex_lock(&sound_mutex);
 272 #ifdef CONFIG_SND_DYNAMIC_MINORS
 273         minor = snd_find_free_minor();
 274 #else
 275         minor = snd_kernel_minor(type, card, dev);
 276         if (minor >= 0 && snd_minors[minor])
 277                 minor = -EBUSY;
 278 #endif
 279         if (minor < 0) {
 280                 mutex_unlock(&sound_mutex);
 281                 kfree(preg);
 282                 return minor;
 283         }
 284         snd_minors[minor] = preg;
 285         preg->dev = device_create(sound_class, device, MKDEV(major, minor),
 286                                   private_data, "%s", name);
 287         if (IS_ERR(preg->dev)) {
 288                 snd_minors[minor] = NULL;
 289                 mutex_unlock(&sound_mutex);
 290                 minor = PTR_ERR(preg->dev);
 291                 kfree(preg);
 292                 return minor;
 293         }
 294
 295         mutex_unlock(&sound_mutex);
 296         return 0;
 297 }
 298
 299 EXPORT_SYMBOL(snd_register_device_for_dev);
 300
 301 /* find the matching minor record
 302  * return the index of snd_minor, or -1 if not found
 303  */
 304 static int find_snd_minor(int type, struct snd_card *card, int dev)
 305 {
 306         int cardnum, minor;
 307         struct snd_minor *mptr;
 308
 309         cardnum = card ? card->number : -1;
 310         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
 311                 if ((mptr = snd_minors[minor]) != NULL &&
 312                     mptr->type == type &&
 313                     mptr->card == cardnum &&
 314                     mptr->device == dev)
 315                         return minor;
 316         return -1;
 317 }
 318
 319 /**
 320  * snd_unregister_device - unregister the device on the given card
 321  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 322  * @card: the card instance
 323  * @dev: the device index
 324  *
 325  * Unregisters the device file already registered via
 326  * snd_register_device().
 327  *
 328  * Returns zero if sucecessful, or a negative error code on failure
 329  */
 330 int snd_unregister_device(int type, struct snd_card *card, int dev)
 331 {
 332         int minor;
 333
 334         mutex_lock(&sound_mutex);
 335         minor = find_snd_minor(type, card, dev);
 336         if (minor < 0) {
 337                 mutex_unlock(&sound_mutex);
 338                 return -EINVAL;
 339         }
 340
 341         device_destroy(sound_class, MKDEV(major, minor));
 342
 343         kfree(snd_minors[minor]);
 344         snd_minors[minor] = NULL;
 345         mutex_unlock(&sound_mutex);
 346         return 0;
 347 }
 348
 349 EXPORT_SYMBOL(snd_unregister_device);
 350
 351 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
 352                               struct device_attribute *attr)
 353 {
 354         int minor, ret = -EINVAL;
 355         struct device *d;
 356
 357         mutex_lock(&sound_mutex);
 358         minor = find_snd_minor(type, card, dev);
 359         if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
 360                 ret = device_create_file(d, attr);
 361         mutex_unlock(&sound_mutex);
 362         return ret;
 363
 364 }
 365
 366 EXPORT_SYMBOL(snd_add_device_sysfs_file);
 367
 368 #ifdef CONFIG_PROC_FS
 369 /*
 370  *  INFO PART
 371  */
 372
 373 static struct snd_info_entry *snd_minor_info_entry;
 374
 375 static const char *snd_device_type_name(int type)
 376 {
 377         switch (type) {
 378         case SNDRV_DEVICE_TYPE_CONTROL:
 379                 return "control";
 380         case SNDRV_DEVICE_TYPE_HWDEP:
 381                 return "hardware dependent";
 382         case SNDRV_DEVICE_TYPE_RAWMIDI:
 383                 return "raw midi";
 384         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 385                 return "digital audio playback";
 386         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 387                 return "digital audio capture";
 388         case SNDRV_DEVICE_TYPE_SEQUENCER:
 389                 return "sequencer";
 390         case SNDRV_DEVICE_TYPE_TIMER:
 391                 return "timer";
 392         default:
 393                 return "?";
 394         }
 395 }
 396
 397 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 398 {
 399         int minor;
 400         struct snd_minor *mptr;
 401
 402         mutex_lock(&sound_mutex);
 403         for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
 404                 if (!(mptr = snd_minors[minor]))
 405                         continue;
 406                 if (mptr->card >= 0) {
 407                         if (mptr->device >= 0)
 408                                 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
 409                                             minor, mptr->card, mptr->device,
 410                                             snd_device_type_name(mptr->type));
 411                         else
 412                                 snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
 413                                             minor, mptr->card,
 414                                             snd_device_type_name(mptr->type));
 415                 } else
 416                         snd_iprintf(buffer, "%3i:        : %s\n", minor,
 417                                     snd_device_type_name(mptr->type));
 418         }
 419         mutex_unlock(&sound_mutex);
 420 }
 421
 422 int __init snd_minor_info_init(void)
 423 {
 424         struct snd_info_entry *entry;
 425
 426         entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
 427         if (entry) {
 428                 entry->c.text.read = snd_minor_info_read;
 429                 if (snd_info_register(entry) < 0) {
 430                         snd_info_free_entry(entry);
 431                         entry = NULL;
 432                 }
 433         }
 434         snd_minor_info_entry = entry;
 435         return 0;
 436 }
 437
 438 int __exit snd_minor_info_done(void)
 439 {
 440         snd_info_free_entry(snd_minor_info_entry);
 441         return 0;
 442 }
 443 #endif /* CONFIG_PROC_FS */
 444
 445 /*
 446  *  INIT PART
 447  */
 448
 449 static int __init alsa_sound_init(void)
 450 {
 451         snd_major = major;
 452         snd_ecards_limit = cards_limit;
 453         if (register_chrdev(major, "alsa", &snd_fops)) {
 454                 snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
 455                 return -EIO;
 456         }
 457         if (snd_info_init() < 0) {
 458                 unregister_chrdev(major, "alsa");
 459                 return -ENOMEM;
 460         }
 461         snd_info_minor_register();
 462 #ifndef MODULE
 463         printk(KERN_INFO "Advanced Linux Sound Architecture Driver Version " CONFIG_SND_VERSION CONFIG_SND_DATE ".\n");
 464 #endif
 465         return 0;
 466 }
 467
 468 static void __exit alsa_sound_exit(void)
 469 {
 470         snd_info_minor_unregister();
 471         snd_info_done();
 472         unregister_chrdev(major, "alsa");
 473 }
 474
 475 subsys_initcall(alsa_sound_init);
 476 module_exit(alsa_sound_exit);