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