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/time.h>
  25 #include <linux/device.h>
  26 #include <linux/moduleparam.h>
  27 #include <sound/core.h>
  28 #include <sound/minors.h>
  29 #include <sound/info.h>
  30 #include <sound/version.h>
  31 #include <sound/control.h>
  32 #include <sound/initval.h>
  33 #include <linux/kmod.h>
  34 #include <linux/mutex.h>
  35
  36 #define SNDRV_OS_MINORS 256
  37
  38 static int major = CONFIG_SND_MAJOR;
  39 int snd_major;
  40 EXPORT_SYMBOL(snd_major);
  41
  42 static int cards_limit = 1;
  43
  44 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
  45 MODULE_DESCRIPTION("Advanced Linux Sound Architecture driver for soundcards.");
  46 MODULE_LICENSE("GPL");
  47 module_param(major, int, 0444);
  48 MODULE_PARM_DESC(major, "Major # for sound driver.");
  49 module_param(cards_limit, int, 0444);
  50 MODULE_PARM_DESC(cards_limit, "Count of auto-loadable soundcards.");
  51 MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR);
  52
  53 /* this one holds the actual max. card number currently available.
  54  * as default, it's identical with cards_limit option.  when more
  55  * modules are loaded manually, this limit number increases, too.
  56  */
  57 int snd_ecards_limit;
  58 EXPORT_SYMBOL(snd_ecards_limit);
  59
  60 static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
  61 static DEFINE_MUTEX(sound_mutex);
  62
  63 #ifdef CONFIG_KMOD
  64
  65 /**
  66  * snd_request_card - try to load the card module
  67  * @card: the card number
  68  *
  69  * Tries to load the module "snd-card-X" for the given card number
  70  * via KMOD.  Returns immediately if already loaded.
  71  */
  72 void snd_request_card(int card)
  73 {
  74         if (! current->fs->root)
  75                 return;
  76         if (snd_card_locked(card))
  77                 return;
  78         if (card < 0 || card >= cards_limit)
  79                 return;
  80         request_module("snd-card-%i", card);
  81 }
  82
  83 EXPORT_SYMBOL(snd_request_card);
  84
  85 static void snd_request_other(int minor)
  86 {
  87         char *str;
  88
  89         if (! current->fs->root)
  90                 return;
  91         switch (minor) {
  92         case SNDRV_MINOR_SEQUENCER:     str = "snd-seq";        break;
  93         case SNDRV_MINOR_TIMER:         str = "snd-timer";      break;
  94         default:                        return;
  95         }
  96         request_module(str);
  97 }
  98
  99 #endif                          /* request_module support */
 100
 101 /**
 102  * snd_lookup_minor_data - get user data of a registered device
 103  * @minor: the minor number
 104  * @type: device type (SNDRV_DEVICE_TYPE_XXX)
 105  *
 106  * Checks that a minor device with the specified type is registered, and returns
 107  * its user data pointer.
 108  */
 109 void *snd_lookup_minor_data(unsigned int minor, int type)
 110 {
 111         struct snd_minor *mreg;
 112         void *private_data;
 113
 114         if (minor >= ARRAY_SIZE(snd_minors))
 115                 return NULL;
 116         mutex_lock(&sound_mutex);
 117         mreg = snd_minors[minor];
 118         if (mreg && mreg->type == type)
 119                 private_data = mreg->private_data;
 120         else
 121                 private_data = NULL;
 122         mutex_unlock(&sound_mutex);
 123         return private_data;
 124 }
 125
 126 EXPORT_SYMBOL(snd_lookup_minor_data);
 127
 128 static int snd_open(struct inode *inode, struct file *file)
 129 {
 130         unsigned int minor = iminor(inode);
 131         struct snd_minor *mptr = NULL;
 132         const struct file_operations *old_fops;
 133         int err = 0;
 134
 135         if (minor >= ARRAY_SIZE(snd_minors))
 136                 return -ENODEV;
 137         mptr = snd_minors[minor];
 138         if (mptr == NULL) {
 139 #ifdef CONFIG_KMOD
 140                 int dev = SNDRV_MINOR_DEVICE(minor);
 141                 if (dev == SNDRV_MINOR_CONTROL) {
 142                         /* /dev/aloadC? */
 143                         int card = SNDRV_MINOR_CARD(minor);
 144                         if (snd_cards[card] == NULL)
 145                                 snd_request_card(card);
 146                 } else if (dev == SNDRV_MINOR_GLOBAL) {
 147                         /* /dev/aloadSEQ */
 148                         snd_request_other(minor);
 149                 }
 150 #ifndef CONFIG_SND_DYNAMIC_MINORS
 151                 /* /dev/snd/{controlC?,seq} */
 152                 mptr = snd_minors[minor];
 153                 if (mptr == NULL)
 154 #endif
 155 #endif
 156                         return -ENODEV;
 157         }
 158         old_fops = file->f_op;
 159         file->f_op = fops_get(mptr->f_ops);
 160         if (file->f_op->open)
 161                 err = file->f_op->open(inode, file);
 162         if (err) {
 163                 fops_put(file->f_op);
 164                 file->f_op = fops_get(old_fops);
 165         }
 166         fops_put(old_fops);
 167         return err;
 168 }
 169
 170 static const struct file_operations snd_fops =
 171 {
 172         .owner =        THIS_MODULE,
 173         .open =         snd_open
 174 };
 175
 176 #ifdef CONFIG_SND_DYNAMIC_MINORS
 177 static int snd_find_free_minor(void)
 178 {
 179         int minor;
 180
 181         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
 182                 /* skip minors still used statically for autoloading devices */
 183                 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL ||
 184                     minor == SNDRV_MINOR_SEQUENCER)
 185                         continue;
 186                 if (!snd_minors[minor])
 187                         return minor;
 188         }
 189         return -EBUSY;
 190 }
 191 #else
 192 static int snd_kernel_minor(int type, struct snd_card *card, int dev)
 193 {
 194         int minor;
 195
 196         switch (type) {
 197         case SNDRV_DEVICE_TYPE_SEQUENCER:
 198         case SNDRV_DEVICE_TYPE_TIMER:
 199                 minor = type;
 200                 break;
 201         case SNDRV_DEVICE_TYPE_CONTROL:
 202                 snd_assert(card != NULL, return -EINVAL);
 203                 minor = SNDRV_MINOR(card->number, type);
 204                 break;
 205         case SNDRV_DEVICE_TYPE_HWDEP:
 206         case SNDRV_DEVICE_TYPE_RAWMIDI:
 207         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 208         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 209                 snd_assert(card != NULL, return -EINVAL);
 210                 minor = SNDRV_MINOR(card->number, type + dev);
 211                 break;
 212         default:
 213                 return -EINVAL;
 214         }
 215         snd_assert(minor >= 0 && minor < SNDRV_OS_MINORS, return -EINVAL);
 216         return minor;
 217 }
 218 #endif
 219
 220 /**
 221  * snd_register_device_for_dev - Register the ALSA device file for the card
 222  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 223  * @card: the card instance
 224  * @dev: the device index
 225  * @f_ops: the file operations
 226  * @private_data: user pointer for f_ops->open()
 227  * @name: the device file name
 228  * @device: the &struct device to link this new device to
 229  *
 230  * Registers an ALSA device file for the given card.
 231  * The operators have to be set in reg parameter.
 232  *
 233  * Returns zero if successful, or a negative error code on failure.
 234  */
 235 int snd_register_device_for_dev(int type, struct snd_card *card, int dev,
 236                                 const struct file_operations *f_ops,
 237                                 void *private_data,
 238                                 const char *name, struct device *device)
 239 {
 240         int minor;
 241         struct snd_minor *preg;
 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         preg->dev = device_create(sound_class, device, MKDEV(major, minor),
 267                                   "%s", name);
 268         if (IS_ERR(preg->dev)) {
 269                 snd_minors[minor] = NULL;
 270                 mutex_unlock(&sound_mutex);
 271                 minor = PTR_ERR(preg->dev);
 272                 kfree(preg);
 273                 return minor;
 274         }
 275
 276         if (preg->dev)
 277                 dev_set_drvdata(preg->dev, private_data);
 278
 279         mutex_unlock(&sound_mutex);
 280         return 0;
 281 }
 282
 283 EXPORT_SYMBOL(snd_register_device_for_dev);
 284
 285 /* find the matching minor record
 286  * return the index of snd_minor, or -1 if not found
 287  */
 288 static int find_snd_minor(int type, struct snd_card *card, int dev)
 289 {
 290         int cardnum, minor;
 291         struct snd_minor *mptr;
 292
 293         cardnum = card ? card->number : -1;
 294         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
 295                 if ((mptr = snd_minors[minor]) != NULL &&
 296                     mptr->type == type &&
 297                     mptr->card == cardnum &&
 298                     mptr->device == dev)
 299                         return minor;
 300         return -1;
 301 }
 302
 303 /**
 304  * snd_unregister_device - unregister the device on the given card
 305  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 306  * @card: the card instance
 307  * @dev: the device index
 308  *
 309  * Unregisters the device file already registered via
 310  * snd_register_device().
 311  *
 312  * Returns zero if sucecessful, or a negative error code on failure
 313  */
 314 int snd_unregister_device(int type, struct snd_card *card, int dev)
 315 {
 316         int minor;
 317
 318         mutex_lock(&sound_mutex);
 319         minor = find_snd_minor(type, card, dev);
 320         if (minor < 0) {
 321                 mutex_unlock(&sound_mutex);
 322                 return -EINVAL;
 323         }
 324
 325         device_destroy(sound_class, MKDEV(major, minor));
 326
 327         kfree(snd_minors[minor]);
 328         snd_minors[minor] = NULL;
 329         mutex_unlock(&sound_mutex);
 330         return 0;
 331 }
 332
 333 EXPORT_SYMBOL(snd_unregister_device);
 334
 335 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
 336                               struct device_attribute *attr)
 337 {
 338         int minor, ret = -EINVAL;
 339         struct device *d;
 340
 341         mutex_lock(&sound_mutex);
 342         minor = find_snd_minor(type, card, dev);
 343         if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL)
 344                 ret = device_create_file(d, attr);
 345         mutex_unlock(&sound_mutex);
 346         return ret;
 347
 348 }
 349
 350 EXPORT_SYMBOL(snd_add_device_sysfs_file);
 351
 352 #ifdef CONFIG_PROC_FS
 353 /*
 354  *  INFO PART
 355  */
 356
 357 static struct snd_info_entry *snd_minor_info_entry;
 358
 359 static const char *snd_device_type_name(int type)
 360 {
 361         switch (type) {
 362         case SNDRV_DEVICE_TYPE_CONTROL:
 363                 return "control";
 364         case SNDRV_DEVICE_TYPE_HWDEP:
 365                 return "hardware dependent";
 366         case SNDRV_DEVICE_TYPE_RAWMIDI:
 367                 return "raw midi";
 368         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 369                 return "digital audio playback";
 370         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 371                 return "digital audio capture";
 372         case SNDRV_DEVICE_TYPE_SEQUENCER:
 373                 return "sequencer";
 374         case SNDRV_DEVICE_TYPE_TIMER:
 375                 return "timer";
 376         default:
 377                 return "?";
 378         }
 379 }
 380
 381 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 382 {
 383         int minor;
 384         struct snd_minor *mptr;
 385
 386         mutex_lock(&sound_mutex);
 387         for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
 388                 if (!(mptr = snd_minors[minor]))
 389                         continue;
 390                 if (mptr->card >= 0) {
 391                         if (mptr->device >= 0)
 392                                 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
 393                                             minor, mptr->card, mptr->device,
 394                                             snd_device_type_name(mptr->type));
 395                         else
 396                                 snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
 397                                             minor, mptr->card,
 398                                             snd_device_type_name(mptr->type));
 399                 } else
 400                         snd_iprintf(buffer, "%3i:        : %s\n", minor,
 401                                     snd_device_type_name(mptr->type));
 402         }
 403         mutex_unlock(&sound_mutex);
 404 }
 405
 406 int __init snd_minor_info_init(void)
 407 {
 408         struct snd_info_entry *entry;
 409
 410         entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
 411         if (entry) {
 412                 entry->c.text.read = snd_minor_info_read;
 413                 if (snd_info_register(entry) < 0) {
 414                         snd_info_free_entry(entry);
 415                         entry = NULL;
 416                 }
 417         }
 418         snd_minor_info_entry = entry;
 419         return 0;
 420 }
 421
 422 int __exit snd_minor_info_done(void)
 423 {
 424         snd_info_free_entry(snd_minor_info_entry);
 425         return 0;
 426 }
 427 #endif /* CONFIG_PROC_FS */
 428
 429 /*
 430  *  INIT PART
 431  */
 432
 433 static int __init alsa_sound_init(void)
 434 {
 435         snd_major = major;
 436         snd_ecards_limit = cards_limit;
 437         if (register_chrdev(major, "alsa", &snd_fops)) {
 438                 snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
 439                 return -EIO;
 440         }
 441         if (snd_info_init() < 0) {
 442                 unregister_chrdev(major, "alsa");
 443                 return -ENOMEM;
 444         }
 445         snd_info_minor_register();
 446 #ifndef MODULE
 447         printk(KERN_INFO "Advanced Linux Sound Architecture Driver Version " CONFIG_SND_VERSION CONFIG_SND_DATE ".\n");
 448 #endif
 449         return 0;
 450 }
 451
 452 static void __exit alsa_sound_exit(void)
 453 {
 454         snd_info_minor_unregister();
 455         snd_info_done();
 456         unregister_chrdev(major, "alsa");
 457 }
 458
 459 module_init(alsa_sound_init)
 460 module_exit(alsa_sound_exit)