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