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 static int __snd_open(struct inode *inode, struct file *file)
 124 {
 125         unsigned int minor = iminor(inode);
 126         struct snd_minor *mptr = NULL;
 127         const struct file_operations *old_fops;
 128         int err = 0;
 129
 130         if (minor >= ARRAY_SIZE(snd_minors))
 131                 return -ENODEV;
 132         mptr = snd_minors[minor];
 133         if (mptr == NULL) {
 134 #ifdef CONFIG_MODULES
 135                 int dev = SNDRV_MINOR_DEVICE(minor);
 136                 if (dev == SNDRV_MINOR_CONTROL) {
 137                         /* /dev/aloadC? */
 138                         int card = SNDRV_MINOR_CARD(minor);
 139                         if (snd_cards[card] == NULL)
 140                                 snd_request_card(card);
 141                 } else if (dev == SNDRV_MINOR_GLOBAL) {
 142                         /* /dev/aloadSEQ */
 143                         snd_request_other(minor);
 144                 }
 145 #ifndef CONFIG_SND_DYNAMIC_MINORS
 146                 /* /dev/snd/{controlC?,seq} */
 147                 mptr = snd_minors[minor];
 148                 if (mptr == NULL)
 149 #endif
 150 #endif
 151                         return -ENODEV;
 152         }
 153         old_fops = file->f_op;
 154         file->f_op = fops_get(mptr->f_ops);
 155         if (file->f_op == NULL) {
 156                 file->f_op = old_fops;
 157                 return -ENODEV;
 158         }
 159         if (file->f_op->open)
 160                 err = file->f_op->open(inode, file);
 161         if (err) {
 162                 fops_put(file->f_op);
 163                 file->f_op = fops_get(old_fops);
 164         }
 165         fops_put(old_fops);
 166         return err;
 167 }
 168
 169
 170 /* BKL pushdown: nasty #ifdef avoidance wrapper */
 171 static int snd_open(struct inode *inode, struct file *file)
 172 {
 173         int ret;
 174
 175         lock_kernel();
 176         ret = __snd_open(inode, file);
 177         unlock_kernel();
 178         return ret;
 179 }
 180
 181 static const struct file_operations snd_fops =
 182 {
 183         .owner =        THIS_MODULE,
 184         .open =         snd_open
 185 };
 186
 187 #ifdef CONFIG_SND_DYNAMIC_MINORS
 188 static int snd_find_free_minor(void)
 189 {
 190         int minor;
 191
 192         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
 193                 /* skip minors still used statically for autoloading devices */
 194                 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL ||
 195                     minor == SNDRV_MINOR_SEQUENCER)
 196                         continue;
 197                 if (!snd_minors[minor])
 198                         return minor;
 199         }
 200         return -EBUSY;
 201 }
 202 #else
 203 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
 204 {
 205         int minor;
 206
 207         switch (type) {
 208         case SNDRV_DEVICE_TYPE_SEQUENCER:
 209         case SNDRV_DEVICE_TYPE_TIMER:
 210                 minor = type;
 211                 break;
 212         case SNDRV_DEVICE_TYPE_CONTROL:
 213                 if (snd_BUG_ON(!card))
 214                         return -EINVAL;
 215                 minor = SNDRV_MINOR(card->number, type);
 216                 break;
 217         case SNDRV_DEVICE_TYPE_HWDEP:
 218         case SNDRV_DEVICE_TYPE_RAWMIDI:
 219         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 220         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 221                 if (snd_BUG_ON(!card))
 222                         return -EINVAL;
 223                 minor = SNDRV_MINOR(card->number, type + dev);
 224                 break;
 225         default:
 226                 return -EINVAL;
 227         }
 228         if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
 229                 return -EINVAL;
 230         return minor;
 231 }
 232 #endif
 233
 234 /**
 235  * snd_register_device_for_dev - Register the ALSA device file for the card
 236  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 237  * @card: the card instance
 238  * @dev: the device index
 239  * @f_ops: the file operations
 240  * @private_data: user pointer for f_ops->open()
 241  * @name: the device file name
 242  * @device: the &struct device to link this new device to
 243  *
 244  * Registers an ALSA device file for the given card.
 245  * The operators have to be set in reg parameter.
 246  *
 247  * Returns zero if successful, or a negative error code on failure.
 248  */
 249 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
 250                                 const struct file_operations *f_ops,
 251                                 void *private_data,
 252                                 const char *name, struct device *device)
 253 {
 254         int minor;
 255         struct snd_minor *preg;
 256
 257         if (snd_BUG_ON(!name))
 258                 return -EINVAL;
 259         preg = kmalloc(sizeof *preg, GFP_KERNEL);
 260         if (preg == NULL)
 261                 return -ENOMEM;
 262         preg->type = type;
 263         preg->card = card ? card->number : -1;
 264         preg->device = dev;
 265         preg->f_ops = f_ops;
 266         preg->private_data = private_data;
 267         mutex_lock(&sound_mutex);
 268 #ifdef CONFIG_SND_DYNAMIC_MINORS
 269         minor = snd_find_free_minor();
 270 #else
 271         minor = snd_kernel_minor(type, card, dev);
 272         if (minor >= 0 && snd_minors[minor])
 273                 minor = -EBUSY;
 274 #endif
 275         if (minor < 0) {
 276                 mutex_unlock(&sound_mutex);
 277                 kfree(preg);
 278                 return minor;
 279         }
 280         snd_minors[minor] = preg;
 281         preg->dev = device_create(sound_class, device, MKDEV(major, minor),
 282                                   private_data, "%s", name);
 283         if (IS_ERR(preg->dev)) {
 284                 snd_minors[minor] = NULL;
 285                 mutex_unlock(&sound_mutex);
 286                 minor = PTR_ERR(preg->dev);
 287                 kfree(preg);
 288                 return minor;
 289         }
 290
 291         mutex_unlock(&sound_mutex);
 292         return 0;
 293 }
 294
 295 EXPORT_SYMBOL(snd_register_device_for_dev);
 296
 297 /* find the matching minor record
 298  * return the index of snd_minor, or -1 if not found
 299  */
 300 static int find_snd_minor(int type, struct snd_card *card, int dev)
 301 {
 302         int cardnum, minor;
 303         struct snd_minor *mptr;
 304
 305         cardnum = card ? card->number : -1;
 306         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
 307                 if ((mptr = snd_minors[minor]) != NULL &&
 308                     mptr->type == type &&
 309                     mptr->card == cardnum &&
 310                     mptr->device == dev)
 311                         return minor;
 312         return -1;
 313 }
 314
 315 /**
 316  * snd_unregister_device - unregister the device on the given card
 317  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 318  * @card: the card instance
 319  * @dev: the device index
 320  *
 321  * Unregisters the device file already registered via
 322  * snd_register_device().
 323  *
 324  * Returns zero if sucecessful, or a negative error code on failure
 325  */
 326 int snd_unregister_device(int type, struct snd_card *card, int dev)
 327 {
 328         int minor;
 329
 330         mutex_lock(&sound_mutex);
 331         minor = find_snd_minor(type, card, dev);
 332         if (minor < 0) {
 333                 mutex_unlock(&sound_mutex);
 334                 return -EINVAL;
 335         }
 336
 337         device_destroy(sound_class, MKDEV(major, minor));
 338
 339         kfree(snd_minors[minor]);
 340         snd_minors[minor] = NULL;
 341         mutex_unlock(&sound_mutex);
 342         return 0;
 343 }
 344
 345 EXPORT_SYMBOL(snd_unregister_device);
 346
 347 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
 348                               struct device_attribute *attr)
 349 {
 350         int minor, ret = -EINVAL;
 351         struct device *d;
 352
 353         mutex_lock(&sound_mutex);
 354         minor = find_snd_minor(type, card, dev);
 355         if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
 356                 ret = device_create_file(d, attr);
 357         mutex_unlock(&sound_mutex);
 358         return ret;
 359
 360 }
 361
 362 EXPORT_SYMBOL(snd_add_device_sysfs_file);
 363
 364 #ifdef CONFIG_PROC_FS
 365 /*
 366  *  INFO PART
 367  */
 368
 369 static struct snd_info_entry *snd_minor_info_entry;
 370
 371 static const char *snd_device_type_name(int type)
 372 {
 373         switch (type) {
 374         case SNDRV_DEVICE_TYPE_CONTROL:
 375                 return "control";
 376         case SNDRV_DEVICE_TYPE_HWDEP:
 377                 return "hardware dependent";
 378         case SNDRV_DEVICE_TYPE_RAWMIDI:
 379                 return "raw midi";
 380         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 381                 return "digital audio playback";
 382         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 383                 return "digital audio capture";
 384         case SNDRV_DEVICE_TYPE_SEQUENCER:
 385                 return "sequencer";
 386         case SNDRV_DEVICE_TYPE_TIMER:
 387                 return "timer";
 388         default:
 389                 return "?";
 390         }
 391 }
 392
 393 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 394 {
 395         int minor;
 396         struct snd_minor *mptr;
 397
 398         mutex_lock(&sound_mutex);
 399         for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
 400                 if (!(mptr = snd_minors[minor]))
 401                         continue;
 402                 if (mptr->card >= 0) {
 403                         if (mptr->device >= 0)
 404                                 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
 405                                             minor, mptr->card, mptr->device,
 406                                             snd_device_type_name(mptr->type));
 407                         else
 408                                 snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
 409                                             minor, mptr->card,
 410                                             snd_device_type_name(mptr->type));
 411                 } else
 412                         snd_iprintf(buffer, "%3i:        : %s\n", minor,
 413                                     snd_device_type_name(mptr->type));
 414         }
 415         mutex_unlock(&sound_mutex);
 416 }
 417
 418 int __init snd_minor_info_init(void)
 419 {
 420         struct snd_info_entry *entry;
 421
 422         entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
 423         if (entry) {
 424                 entry->c.text.read = snd_minor_info_read;
 425                 if (snd_info_register(entry) < 0) {
 426                         snd_info_free_entry(entry);
 427                         entry = NULL;
 428                 }
 429         }
 430         snd_minor_info_entry = entry;
 431         return 0;
 432 }
 433
 434 int __exit snd_minor_info_done(void)
 435 {
 436         snd_info_free_entry(snd_minor_info_entry);
 437         return 0;
 438 }
 439 #endif /* CONFIG_PROC_FS */
 440
 441 /*
 442  *  INIT PART
 443  */
 444
 445 static int __init alsa_sound_init(void)
 446 {
 447         snd_major = major;
 448         snd_ecards_limit = cards_limit;
 449         if (register_chrdev(major, "alsa", &snd_fops)) {
 450                 snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
 451                 return -EIO;
 452         }
 453         if (snd_info_init() < 0) {
 454                 unregister_chrdev(major, "alsa");
 455                 return -ENOMEM;
 456         }
 457         snd_info_minor_register();
 458 #ifndef MODULE
 459         printk(KERN_INFO "Advanced Linux Sound Architecture Driver Version " CONFIG_SND_VERSION CONFIG_SND_DATE ".\n");
 460 #endif
 461         return 0;
 462 }
 463
 464 static void __exit alsa_sound_exit(void)
 465 {
 466         snd_info_minor_unregister();
 467         snd_info_done();
 468         unregister_chrdev(major, "alsa");
 469 }
 470
 471 module_init(alsa_sound_init)
 472 module_exit(alsa_sound_exit)