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