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/module.h> 27 #include <sound/core.h> 28 #include <sound/minors.h> 29 #include <sound/info.h> 30 #include <sound/control.h> 31 #include <sound/initval.h> 32 #include <linux/kmod.h> 33 #include <linux/mutex.h> 34 35 static int major = CONFIG_SND_MAJOR; 36 int snd_major; 37 EXPORT_SYMBOL(snd_major); 38 39 static int cards_limit = 1; 40 41 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>"); 42 MODULE_DESCRIPTION("Advanced Linux Sound Architecture driver for soundcards."); 43 MODULE_LICENSE("GPL"); 44 module_param(major, int, 0444); 45 MODULE_PARM_DESC(major, "Major # for sound driver."); 46 module_param(cards_limit, int, 0444); 47 MODULE_PARM_DESC(cards_limit, "Count of auto-loadable soundcards."); 48 MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR); 49 50 /* this one holds the actual max. card number currently available. 51 * as default, it's identical with cards_limit option. when more 52 * modules are loaded manually, this limit number increases, too. 53 */ 54 int snd_ecards_limit; 55 EXPORT_SYMBOL(snd_ecards_limit); 56 57 static struct snd_minor *snd_minors[SNDRV_OS_MINORS]; 58 static DEFINE_MUTEX(sound_mutex); 59 60 #ifdef CONFIG_MODULES 61 62 /** 63 * snd_request_card - try to load the card module 64 * @card: the card number 65 * 66 * Tries to load the module "snd-card-X" for the given card number 67 * via request_module. Returns immediately if already loaded. 68 */ 69 void snd_request_card(int card) 70 { 71 if (snd_card_locked(card)) 72 return; 73 if (card < 0 || card >= cards_limit) 74 return; 75 request_module("snd-card-%i", card); 76 } 77 78 EXPORT_SYMBOL(snd_request_card); 79 80 static void snd_request_other(int minor) 81 { 82 char *str; 83 84 switch (minor) { 85 case SNDRV_MINOR_SEQUENCER: str = "snd-seq"; break; 86 case SNDRV_MINOR_TIMER: str = "snd-timer"; break; 87 default: return; 88 } 89 request_module(str); 90 } 91 92 #endif /* modular kernel */ 93 94 /** 95 * snd_lookup_minor_data - get user data of a registered device 96 * @minor: the minor number 97 * @type: device type (SNDRV_DEVICE_TYPE_XXX) 98 * 99 * Checks that a minor device with the specified type is registered, and returns 100 * its user data pointer. 101 * 102 * This function increments the reference counter of the card instance 103 * if an associated instance with the given minor number and type is found. 104 * The caller must call snd_card_unref() appropriately later. 105 * 106 * Return: The user data pointer if the specified device is found. %NULL 107 * otherwise. 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 if (private_data && mreg->card_ptr) 121 atomic_inc(&mreg->card_ptr->refcount); 122 } else 123 private_data = NULL; 124 mutex_unlock(&sound_mutex); 125 return private_data; 126 } 127 128 EXPORT_SYMBOL(snd_lookup_minor_data); 129 130 #ifdef CONFIG_MODULES 131 static struct snd_minor *autoload_device(unsigned int minor) 132 { 133 int dev; 134 mutex_unlock(&sound_mutex); /* release lock temporarily */ 135 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 mutex_lock(&sound_mutex); /* reacuire lock */ 146 return snd_minors[minor]; 147 } 148 #else /* !CONFIG_MODULES */ 149 #define autoload_device(minor) NULL 150 #endif /* CONFIG_MODULES */ 151 152 static int snd_open(struct inode *inode, struct file *file) 153 { 154 unsigned int minor = iminor(inode); 155 struct snd_minor *mptr = NULL; 156 const struct file_operations *old_fops; 157 int err = 0; 158 159 if (minor >= ARRAY_SIZE(snd_minors)) 160 return -ENODEV; 161 mutex_lock(&sound_mutex); 162 mptr = snd_minors[minor]; 163 if (mptr == NULL) { 164 mptr = autoload_device(minor); 165 if (!mptr) { 166 mutex_unlock(&sound_mutex); 167 return -ENODEV; 168 } 169 } 170 old_fops = file->f_op; 171 file->f_op = fops_get(mptr->f_ops); 172 if (file->f_op == NULL) { 173 file->f_op = old_fops; 174 err = -ENODEV; 175 } 176 mutex_unlock(&sound_mutex); 177 if (err < 0) 178 return err; 179 180 if (file->f_op->open) { 181 err = file->f_op->open(inode, file); 182 if (err) { 183 fops_put(file->f_op); 184 file->f_op = fops_get(old_fops); 185 } 186 } 187 fops_put(old_fops); 188 return err; 189 } 190 191 static const struct file_operations snd_fops = 192 { 193 .owner = THIS_MODULE, 194 .open = snd_open, 195 .llseek = noop_llseek, 196 }; 197 198 #ifdef CONFIG_SND_DYNAMIC_MINORS 199 static int snd_find_free_minor(int type) 200 { 201 int minor; 202 203 /* static minors for module auto loading */ 204 if (type == SNDRV_DEVICE_TYPE_SEQUENCER) 205 return SNDRV_MINOR_SEQUENCER; 206 if (type == SNDRV_DEVICE_TYPE_TIMER) 207 return SNDRV_MINOR_TIMER; 208 209 for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) { 210 /* skip static minors still used for module auto loading */ 211 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL) 212 continue; 213 if (minor == SNDRV_MINOR_SEQUENCER || 214 minor == SNDRV_MINOR_TIMER) 215 continue; 216 if (!snd_minors[minor]) 217 return minor; 218 } 219 return -EBUSY; 220 } 221 #else 222 static int snd_kernel_minor(int type, struct snd_card *card, int dev) 223 { 224 int minor; 225 226 switch (type) { 227 case SNDRV_DEVICE_TYPE_SEQUENCER: 228 case SNDRV_DEVICE_TYPE_TIMER: 229 minor = type; 230 break; 231 case SNDRV_DEVICE_TYPE_CONTROL: 232 if (snd_BUG_ON(!card)) 233 return -EINVAL; 234 minor = SNDRV_MINOR(card->number, type); 235 break; 236 case SNDRV_DEVICE_TYPE_HWDEP: 237 case SNDRV_DEVICE_TYPE_RAWMIDI: 238 case SNDRV_DEVICE_TYPE_PCM_PLAYBACK: 239 case SNDRV_DEVICE_TYPE_PCM_CAPTURE: 240 case SNDRV_DEVICE_TYPE_COMPRESS: 241 if (snd_BUG_ON(!card)) 242 return -EINVAL; 243 minor = SNDRV_MINOR(card->number, type + dev); 244 break; 245 default: 246 return -EINVAL; 247 } 248 if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS)) 249 return -EINVAL; 250 return minor; 251 } 252 #endif 253 254 /** 255 * snd_register_device_for_dev - Register the ALSA device file for the card 256 * @type: the device type, SNDRV_DEVICE_TYPE_XXX 257 * @card: the card instance 258 * @dev: the device index 259 * @f_ops: the file operations 260 * @private_data: user pointer for f_ops->open() 261 * @name: the device file name 262 * @device: the &struct device to link this new device to 263 * 264 * Registers an ALSA device file for the given card. 265 * The operators have to be set in reg parameter. 266 * 267 * Return: Zero if successful, or a negative error code on failure. 268 */ 269 int snd_register_device_for_dev(int type, struct snd_card *card, int dev, 270 const struct file_operations *f_ops, 271 void *private_data, 272 const char *name, struct device *device) 273 { 274 int minor; 275 struct snd_minor *preg; 276 277 if (snd_BUG_ON(!name)) 278 return -EINVAL; 279 preg = kmalloc(sizeof *preg, GFP_KERNEL); 280 if (preg == NULL) 281 return -ENOMEM; 282 preg->type = type; 283 preg->card = card ? card->number : -1; 284 preg->device = dev; 285 preg->f_ops = f_ops; 286 preg->private_data = private_data; 287 preg->card_ptr = card; 288 mutex_lock(&sound_mutex); 289 #ifdef CONFIG_SND_DYNAMIC_MINORS 290 minor = snd_find_free_minor(type); 291 #else 292 minor = snd_kernel_minor(type, card, dev); 293 if (minor >= 0 && snd_minors[minor]) 294 minor = -EBUSY; 295 #endif 296 if (minor < 0) { 297 mutex_unlock(&sound_mutex); 298 kfree(preg); 299 return minor; 300 } 301 snd_minors[minor] = preg; 302 preg->dev = device_create(sound_class, device, MKDEV(major, minor), 303 private_data, "%s", name); 304 if (IS_ERR(preg->dev)) { 305 snd_minors[minor] = NULL; 306 mutex_unlock(&sound_mutex); 307 minor = PTR_ERR(preg->dev); 308 kfree(preg); 309 return minor; 310 } 311 312 mutex_unlock(&sound_mutex); 313 return 0; 314 } 315 316 EXPORT_SYMBOL(snd_register_device_for_dev); 317 318 /* find the matching minor record 319 * return the index of snd_minor, or -1 if not found 320 */ 321 static int find_snd_minor(int type, struct snd_card *card, int dev) 322 { 323 int cardnum, minor; 324 struct snd_minor *mptr; 325 326 cardnum = card ? card->number : -1; 327 for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) 328 if ((mptr = snd_minors[minor]) != NULL && 329 mptr->type == type && 330 mptr->card == cardnum && 331 mptr->device == dev) 332 return minor; 333 return -1; 334 } 335 336 /** 337 * snd_unregister_device - unregister the device on the given card 338 * @type: the device type, SNDRV_DEVICE_TYPE_XXX 339 * @card: the card instance 340 * @dev: the device index 341 * 342 * Unregisters the device file already registered via 343 * snd_register_device(). 344 * 345 * Return: Zero if successful, or a negative error code on failure. 346 */ 347 int snd_unregister_device(int type, struct snd_card *card, int dev) 348 { 349 int minor; 350 351 mutex_lock(&sound_mutex); 352 minor = find_snd_minor(type, card, dev); 353 if (minor < 0) { 354 mutex_unlock(&sound_mutex); 355 return -EINVAL; 356 } 357 358 device_destroy(sound_class, MKDEV(major, minor)); 359 360 kfree(snd_minors[minor]); 361 snd_minors[minor] = NULL; 362 mutex_unlock(&sound_mutex); 363 return 0; 364 } 365 366 EXPORT_SYMBOL(snd_unregister_device); 367 368 int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev, 369 struct device_attribute *attr) 370 { 371 int minor, ret = -EINVAL; 372 struct device *d; 373 374 mutex_lock(&sound_mutex); 375 minor = find_snd_minor(type, card, dev); 376 if (minor >= 0 && (d = snd_minors[minor]->dev) != NULL) 377 ret = device_create_file(d, attr); 378 mutex_unlock(&sound_mutex); 379 return ret; 380 381 } 382 383 EXPORT_SYMBOL(snd_add_device_sysfs_file); 384 385 #ifdef CONFIG_PROC_FS 386 /* 387 * INFO PART 388 */ 389 390 static struct snd_info_entry *snd_minor_info_entry; 391 392 static const char *snd_device_type_name(int type) 393 { 394 switch (type) { 395 case SNDRV_DEVICE_TYPE_CONTROL: 396 return "control"; 397 case SNDRV_DEVICE_TYPE_HWDEP: 398 return "hardware dependent"; 399 case SNDRV_DEVICE_TYPE_RAWMIDI: 400 return "raw midi"; 401 case SNDRV_DEVICE_TYPE_PCM_PLAYBACK: 402 return "digital audio playback"; 403 case SNDRV_DEVICE_TYPE_PCM_CAPTURE: 404 return "digital audio capture"; 405 case SNDRV_DEVICE_TYPE_SEQUENCER: 406 return "sequencer"; 407 case SNDRV_DEVICE_TYPE_TIMER: 408 return "timer"; 409 default: 410 return "?"; 411 } 412 } 413 414 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer) 415 { 416 int minor; 417 struct snd_minor *mptr; 418 419 mutex_lock(&sound_mutex); 420 for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) { 421 if (!(mptr = snd_minors[minor])) 422 continue; 423 if (mptr->card >= 0) { 424 if (mptr->device >= 0) 425 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n", 426 minor, mptr->card, mptr->device, 427 snd_device_type_name(mptr->type)); 428 else 429 snd_iprintf(buffer, "%3i: [%2i] : %s\n", 430 minor, mptr->card, 431 snd_device_type_name(mptr->type)); 432 } else 433 snd_iprintf(buffer, "%3i: : %s\n", minor, 434 snd_device_type_name(mptr->type)); 435 } 436 mutex_unlock(&sound_mutex); 437 } 438 439 int __init snd_minor_info_init(void) 440 { 441 struct snd_info_entry *entry; 442 443 entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL); 444 if (entry) { 445 entry->c.text.read = snd_minor_info_read; 446 if (snd_info_register(entry) < 0) { 447 snd_info_free_entry(entry); 448 entry = NULL; 449 } 450 } 451 snd_minor_info_entry = entry; 452 return 0; 453 } 454 455 int __exit snd_minor_info_done(void) 456 { 457 snd_info_free_entry(snd_minor_info_entry); 458 return 0; 459 } 460 #endif /* CONFIG_PROC_FS */ 461 462 /* 463 * INIT PART 464 */ 465 466 static int __init alsa_sound_init(void) 467 { 468 snd_major = major; 469 snd_ecards_limit = cards_limit; 470 if (register_chrdev(major, "alsa", &snd_fops)) { 471 snd_printk(KERN_ERR "unable to register native major device number %d\n", major); 472 return -EIO; 473 } 474 if (snd_info_init() < 0) { 475 unregister_chrdev(major, "alsa"); 476 return -ENOMEM; 477 } 478 snd_info_minor_register(); 479 #ifndef MODULE 480 printk(KERN_INFO "Advanced Linux Sound Architecture Driver Initialized.\n"); 481 #endif 482 return 0; 483 } 484 485 static void __exit alsa_sound_exit(void) 486 { 487 snd_info_minor_unregister(); 488 snd_info_done(); 489 unregister_chrdev(major, "alsa"); 490 } 491 492 subsys_initcall(alsa_sound_init); 493 module_exit(alsa_sound_exit); 494