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/devfs_fs_kernel.h>
  36 #include <linux/mutex.h>
  37
  38 #define SNDRV_OS_MINORS 256
  39
  40 static int major = CONFIG_SND_MAJOR;
  41 int snd_major;
  42 EXPORT_SYMBOL(snd_major);
  43
  44 static int cards_limit = 1;
  45 static int device_mode = S_IFCHR | S_IRUGO | S_IWUGO;
  46
  47 MODULE_AUTHOR("Jaroslav Kysela <perex@suse.cz>");
  48 MODULE_DESCRIPTION("Advanced Linux Sound Architecture driver for soundcards.");
  49 MODULE_LICENSE("GPL");
  50 module_param(major, int, 0444);
  51 MODULE_PARM_DESC(major, "Major # for sound driver.");
  52 module_param(cards_limit, int, 0444);
  53 MODULE_PARM_DESC(cards_limit, "Count of auto-loadable soundcards.");
  54 #ifdef CONFIG_DEVFS_FS
  55 module_param(device_mode, int, 0444);
  56 MODULE_PARM_DESC(device_mode, "Device file permission mask for devfs.");
  57 #endif
  58 MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR);
  59
  60 /* this one holds the actual max. card number currently available.
  61  * as default, it's identical with cards_limit option.  when more
  62  * modules are loaded manually, this limit number increases, too.
  63  */
  64 int snd_ecards_limit;
  65 EXPORT_SYMBOL(snd_ecards_limit);
  66
  67 static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
  68 static DEFINE_MUTEX(sound_mutex);
  69
  70 extern struct class *sound_class;
  71
  72
  73 #ifdef CONFIG_KMOD
  74
  75 /**
  76  * snd_request_card - try to load the card module
  77  * @card: the card number
  78  *
  79  * Tries to load the module "snd-card-X" for the given card number
  80  * via KMOD.  Returns immediately if already loaded.
  81  */
  82 void snd_request_card(int card)
  83 {
  84         int locked;
  85
  86         if (! current->fs->root)
  87                 return;
  88         read_lock(&snd_card_rwlock);
  89         locked = snd_cards_lock & (1 << card);
  90         read_unlock(&snd_card_rwlock);
  91         if (locked)
  92                 return;
  93         if (card < 0 || card >= cards_limit)
  94                 return;
  95         request_module("snd-card-%i", card);
  96 }
  97
  98 EXPORT_SYMBOL(snd_request_card);
  99
 100 static void snd_request_other(int minor)
 101 {
 102         char *str;
 103
 104         if (! current->fs->root)
 105                 return;
 106         switch (minor) {
 107         case SNDRV_MINOR_SEQUENCER:     str = "snd-seq";        break;
 108         case SNDRV_MINOR_TIMER:         str = "snd-timer";      break;
 109         default:                        return;
 110         }
 111         request_module(str);
 112 }
 113
 114 #endif                          /* request_module support */
 115
 116 /**
 117  * snd_lookup_minor_data - get user data of a registered device
 118  * @minor: the minor number
 119  * @type: device type (SNDRV_DEVICE_TYPE_XXX)
 120  *
 121  * Checks that a minor device with the specified type is registered, and returns
 122  * its user data pointer.
 123  */
 124 void *snd_lookup_minor_data(unsigned int minor, int type)
 125 {
 126         struct snd_minor *mreg;
 127         void *private_data;
 128
 129         if (minor >= ARRAY_SIZE(snd_minors))
 130                 return NULL;
 131         mutex_lock(&sound_mutex);
 132         mreg = snd_minors[minor];
 133         if (mreg && mreg->type == type)
 134                 private_data = mreg->private_data;
 135         else
 136                 private_data = NULL;
 137         mutex_unlock(&sound_mutex);
 138         return private_data;
 139 }
 140
 141 EXPORT_SYMBOL(snd_lookup_minor_data);
 142
 143 static int snd_open(struct inode *inode, struct file *file)
 144 {
 145         unsigned int minor = iminor(inode);
 146         struct snd_minor *mptr = NULL;
 147         const struct file_operations *old_fops;
 148         int err = 0;
 149
 150         if (minor >= ARRAY_SIZE(snd_minors))
 151                 return -ENODEV;
 152         mptr = snd_minors[minor];
 153         if (mptr == NULL) {
 154 #ifdef CONFIG_KMOD
 155                 int dev = SNDRV_MINOR_DEVICE(minor);
 156                 if (dev == SNDRV_MINOR_CONTROL) {
 157                         /* /dev/aloadC? */
 158                         int card = SNDRV_MINOR_CARD(minor);
 159                         if (snd_cards[card] == NULL)
 160                                 snd_request_card(card);
 161                 } else if (dev == SNDRV_MINOR_GLOBAL) {
 162                         /* /dev/aloadSEQ */
 163                         snd_request_other(minor);
 164                 }
 165 #ifndef CONFIG_SND_DYNAMIC_MINORS
 166                 /* /dev/snd/{controlC?,seq} */
 167                 mptr = snd_minors[minor];
 168                 if (mptr == NULL)
 169 #endif
 170 #endif
 171                         return -ENODEV;
 172         }
 173         old_fops = file->f_op;
 174         file->f_op = fops_get(mptr->f_ops);
 175         if (file->f_op->open)
 176                 err = file->f_op->open(inode, file);
 177         if (err) {
 178                 fops_put(file->f_op);
 179                 file->f_op = fops_get(old_fops);
 180         }
 181         fops_put(old_fops);
 182         return err;
 183 }
 184
 185 static struct file_operations snd_fops =
 186 {
 187         .owner =        THIS_MODULE,
 188         .open =         snd_open
 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                 snd_assert(card != NULL, return -EINVAL);
 218                 minor = SNDRV_MINOR(card->number, type);
 219                 break;
 220         case SNDRV_DEVICE_TYPE_HWDEP:
 221         case SNDRV_DEVICE_TYPE_RAWMIDI:
 222         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 223         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 224                 snd_assert(card != NULL, return -EINVAL);
 225                 minor = SNDRV_MINOR(card->number, type + dev);
 226                 break;
 227         default:
 228                 return -EINVAL;
 229         }
 230         snd_assert(minor >= 0 && minor < SNDRV_OS_MINORS, return -EINVAL);
 231         return minor;
 232 }
 233 #endif
 234
 235 /**
 236  * snd_register_device - Register the ALSA device file for the card
 237  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 238  * @card: the card instance
 239  * @dev: the device index
 240  * @f_ops: the file operations
 241  * @private_data: user pointer for f_ops->open()
 242  * @name: the device file name
 243  *
 244  * Registers an ALSA device file for the given card.
 245  * The operators have to be set in reg parameter.
 246  *
 247  * Retrurns zero if successful, or a negative error code on failure.
 248  */
 249 int snd_register_device(int type, struct snd_card *card, int dev,
 250                         const struct file_operations *f_ops, void *private_data,
 251                         const char *name)
 252 {
 253         int minor;
 254         struct snd_minor *preg;
 255         struct device *device = NULL;
 256
 257         snd_assert(name, return -EINVAL);
 258         preg = kmalloc(sizeof(struct snd_minor) + strlen(name) + 1, GFP_KERNEL);
 259         if (preg == NULL)
 260                 return -ENOMEM;
 261         preg->type = type;
 262         preg->card = card ? card->number : -1;
 263         preg->device = dev;
 264         preg->f_ops = f_ops;
 265         preg->private_data = private_data;
 266         strcpy(preg->name, name);
 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         if (type != SNDRV_DEVICE_TYPE_CONTROL || preg->card >= cards_limit)
 282                 devfs_mk_cdev(MKDEV(major, minor), S_IFCHR | device_mode, "snd/%s", name);
 283         if (card)
 284                 device = card->dev;
 285         class_device_create(sound_class, NULL, MKDEV(major, minor), device, "%s", name);
 286
 287         mutex_unlock(&sound_mutex);
 288         return 0;
 289 }
 290
 291 EXPORT_SYMBOL(snd_register_device);
 292
 293 /**
 294  * snd_unregister_device - unregister the device on the given card
 295  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
 296  * @card: the card instance
 297  * @dev: the device index
 298  *
 299  * Unregisters the device file already registered via
 300  * snd_register_device().
 301  *
 302  * Returns zero if sucecessful, or a negative error code on failure
 303  */
 304 int snd_unregister_device(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         mutex_lock(&sound_mutex);
 311         for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
 312                 if ((mptr = snd_minors[minor]) != NULL &&
 313                     mptr->type == type &&
 314                     mptr->card == cardnum &&
 315                     mptr->device == dev)
 316                         break;
 317         if (minor == ARRAY_SIZE(snd_minors)) {
 318                 mutex_unlock(&sound_mutex);
 319                 return -EINVAL;
 320         }
 321
 322         if (mptr->type != SNDRV_DEVICE_TYPE_CONTROL ||
 323             mptr->card >= cards_limit)                  /* created in sound.c */
 324                 devfs_remove("snd/%s", mptr->name);
 325         class_device_destroy(sound_class, MKDEV(major, minor));
 326
 327         snd_minors[minor] = NULL;
 328         mutex_unlock(&sound_mutex);
 329         kfree(mptr);
 330         return 0;
 331 }
 332
 333 EXPORT_SYMBOL(snd_unregister_device);
 334
 335 #ifdef CONFIG_PROC_FS
 336 /*
 337  *  INFO PART
 338  */
 339
 340 static struct snd_info_entry *snd_minor_info_entry = NULL;
 341
 342 static const char *snd_device_type_name(int type)
 343 {
 344         switch (type) {
 345         case SNDRV_DEVICE_TYPE_CONTROL:
 346                 return "control";
 347         case SNDRV_DEVICE_TYPE_HWDEP:
 348                 return "hardware dependent";
 349         case SNDRV_DEVICE_TYPE_RAWMIDI:
 350                 return "raw midi";
 351         case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
 352                 return "digital audio playback";
 353         case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
 354                 return "digital audio capture";
 355         case SNDRV_DEVICE_TYPE_SEQUENCER:
 356                 return "sequencer";
 357         case SNDRV_DEVICE_TYPE_TIMER:
 358                 return "timer";
 359         default:
 360                 return "?";
 361         }
 362 }
 363
 364 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 365 {
 366         int minor;
 367         struct snd_minor *mptr;
 368
 369         mutex_lock(&sound_mutex);
 370         for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
 371                 if (!(mptr = snd_minors[minor]))
 372                         continue;
 373                 if (mptr->card >= 0) {
 374                         if (mptr->device >= 0)
 375                                 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
 376                                             minor, mptr->card, mptr->device,
 377                                             snd_device_type_name(mptr->type));
 378                         else
 379                                 snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
 380                                             minor, mptr->card,
 381                                             snd_device_type_name(mptr->type));
 382                 } else
 383                         snd_iprintf(buffer, "%3i:        : %s\n", minor,
 384                                     snd_device_type_name(mptr->type));
 385         }
 386         mutex_unlock(&sound_mutex);
 387 }
 388
 389 int __init snd_minor_info_init(void)
 390 {
 391         struct snd_info_entry *entry;
 392
 393         entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
 394         if (entry) {
 395                 entry->c.text.read_size = PAGE_SIZE;
 396                 entry->c.text.read = snd_minor_info_read;
 397                 if (snd_info_register(entry) < 0) {
 398                         snd_info_free_entry(entry);
 399                         entry = NULL;
 400                 }
 401         }
 402         snd_minor_info_entry = entry;
 403         return 0;
 404 }
 405
 406 int __exit snd_minor_info_done(void)
 407 {
 408         if (snd_minor_info_entry)
 409                 snd_info_unregister(snd_minor_info_entry);
 410         return 0;
 411 }
 412 #endif /* CONFIG_PROC_FS */
 413
 414 /*
 415  *  INIT PART
 416  */
 417
 418 static int __init alsa_sound_init(void)
 419 {
 420         short controlnum;
 421
 422         snd_major = major;
 423         snd_ecards_limit = cards_limit;
 424         devfs_mk_dir("snd");
 425         if (register_chrdev(major, "alsa", &snd_fops)) {
 426                 snd_printk(KERN_ERR "unable to register native major device number %d\n", major);
 427                 devfs_remove("snd");
 428                 return -EIO;
 429         }
 430         if (snd_info_init() < 0) {
 431                 unregister_chrdev(major, "alsa");
 432                 devfs_remove("snd");
 433                 return -ENOMEM;
 434         }
 435         snd_info_minor_register();
 436         for (controlnum = 0; controlnum < cards_limit; controlnum++)
 437                 devfs_mk_cdev(MKDEV(major, controlnum<<5), S_IFCHR | device_mode, "snd/controlC%d", controlnum);
 438 #ifndef MODULE
 439         printk(KERN_INFO "Advanced Linux Sound Architecture Driver Version " CONFIG_SND_VERSION CONFIG_SND_DATE ".\n");
 440 #endif
 441         return 0;
 442 }
 443
 444 static void __exit alsa_sound_exit(void)
 445 {
 446         short controlnum;
 447
 448         for (controlnum = 0; controlnum < cards_limit; controlnum++)
 449                 devfs_remove("snd/controlC%d", controlnum);
 450
 451         snd_info_minor_unregister();
 452         snd_info_done();
 453         if (unregister_chrdev(major, "alsa") != 0)
 454                 snd_printk(KERN_ERR "unable to unregister major device number %d\n", major);
 455         devfs_remove("snd");
 456 }
 457
 458 module_init(alsa_sound_init)
 459 module_exit(alsa_sound_exit)