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 get_device(&mreg->card_ptr->card_dev); 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 *new_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 new_fops = fops_get(mptr->f_ops); 171 mutex_unlock(&sound_mutex); 172 if (!new_fops) 173 return -ENODEV; 174 replace_fops(file, new_fops); 175 176 if (file->f_op->open) 177 err = file->f_op->open(inode, file); 178 return err; 179 } 180 181 static const struct file_operations snd_fops = 182 { 183 .owner = THIS_MODULE, 184 .open = snd_open, 185 .llseek = noop_llseek, 186 }; 187 188 #ifdef CONFIG_SND_DYNAMIC_MINORS 189 static int snd_find_free_minor(int type, struct snd_card *card, int dev) 190 { 191 int minor; 192 193 /* static minors for module auto loading */ 194 if (type == SNDRV_DEVICE_TYPE_SEQUENCER) 195 return SNDRV_MINOR_SEQUENCER; 196 if (type == SNDRV_DEVICE_TYPE_TIMER) 197 return SNDRV_MINOR_TIMER; 198 199 for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) { 200 /* skip static minors still used for module auto loading */ 201 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL) 202 continue; 203 if (minor == SNDRV_MINOR_SEQUENCER || 204 minor == SNDRV_MINOR_TIMER) 205 continue; 206 if (!snd_minors[minor]) 207 return minor; 208 } 209 return -EBUSY; 210 } 211 #else 212 static int snd_find_free_minor(int type, struct snd_card *card, int dev) 213 { 214 int minor; 215 216 switch (type) { 217 case SNDRV_DEVICE_TYPE_SEQUENCER: 218 case SNDRV_DEVICE_TYPE_TIMER: 219 minor = type; 220 break; 221 case SNDRV_DEVICE_TYPE_CONTROL: 222 if (snd_BUG_ON(!card)) 223 return -EINVAL; 224 minor = SNDRV_MINOR(card->number, type); 225 break; 226 case SNDRV_DEVICE_TYPE_HWDEP: 227 case SNDRV_DEVICE_TYPE_RAWMIDI: 228 case SNDRV_DEVICE_TYPE_PCM_PLAYBACK: 229 case SNDRV_DEVICE_TYPE_PCM_CAPTURE: 230 case SNDRV_DEVICE_TYPE_COMPRESS: 231 if (snd_BUG_ON(!card)) 232 return -EINVAL; 233 minor = SNDRV_MINOR(card->number, type + dev); 234 break; 235 default: 236 return -EINVAL; 237 } 238 if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS)) 239 return -EINVAL; 240 if (snd_minors[minor]) 241 return -EBUSY; 242 return minor; 243 } 244 #endif 245 246 /** 247 * snd_register_device - Register the ALSA device file for the card 248 * @type: the device type, SNDRV_DEVICE_TYPE_XXX 249 * @card: the card instance 250 * @dev: the device index 251 * @f_ops: the file operations 252 * @private_data: user pointer for f_ops->open() 253 * @device: the device to register 254 * 255 * Registers an ALSA device file for the given card. 256 * The operators have to be set in reg parameter. 257 * 258 * Return: Zero if successful, or a negative error code on failure. 259 */ 260 int snd_register_device(int type, struct snd_card *card, int dev, 261 const struct file_operations *f_ops, 262 void *private_data, struct device *device) 263 { 264 int minor; 265 int err = 0; 266 struct snd_minor *preg; 267 268 if (snd_BUG_ON(!device)) 269 return -EINVAL; 270 271 preg = kmalloc(sizeof *preg, GFP_KERNEL); 272 if (preg == NULL) 273 return -ENOMEM; 274 preg->type = type; 275 preg->card = card ? card->number : -1; 276 preg->device = dev; 277 preg->f_ops = f_ops; 278 preg->private_data = private_data; 279 preg->card_ptr = card; 280 mutex_lock(&sound_mutex); 281 minor = snd_find_free_minor(type, card, dev); 282 if (minor < 0) { 283 err = minor; 284 goto error; 285 } 286 287 preg->dev = device; 288 device->devt = MKDEV(major, minor); 289 err = device_add(device); 290 if (err < 0) 291 goto error; 292 293 snd_minors[minor] = preg; 294 error: 295 mutex_unlock(&sound_mutex); 296 if (err < 0) 297 kfree(preg); 298 return err; 299 } 300 EXPORT_SYMBOL(snd_register_device); 301 302 /** 303 * snd_unregister_device - unregister the device on the given card 304 * @dev: the device instance 305 * 306 * Unregisters the device file already registered via 307 * snd_register_device(). 308 * 309 * Return: Zero if successful, or a negative error code on failure. 310 */ 311 int snd_unregister_device(struct device *dev) 312 { 313 int minor; 314 struct snd_minor *preg; 315 316 mutex_lock(&sound_mutex); 317 for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) { 318 preg = snd_minors[minor]; 319 if (preg && preg->dev == dev) { 320 snd_minors[minor] = NULL; 321 device_del(dev); 322 kfree(preg); 323 break; 324 } 325 } 326 mutex_unlock(&sound_mutex); 327 if (minor >= ARRAY_SIZE(snd_minors)) 328 return -ENOENT; 329 return 0; 330 } 331 EXPORT_SYMBOL(snd_unregister_device); 332 333 #ifdef CONFIG_SND_PROC_FS 334 /* 335 * INFO PART 336 */ 337 static const char *snd_device_type_name(int type) 338 { 339 switch (type) { 340 case SNDRV_DEVICE_TYPE_CONTROL: 341 return "control"; 342 case SNDRV_DEVICE_TYPE_HWDEP: 343 return "hardware dependent"; 344 case SNDRV_DEVICE_TYPE_RAWMIDI: 345 return "raw midi"; 346 case SNDRV_DEVICE_TYPE_PCM_PLAYBACK: 347 return "digital audio playback"; 348 case SNDRV_DEVICE_TYPE_PCM_CAPTURE: 349 return "digital audio capture"; 350 case SNDRV_DEVICE_TYPE_SEQUENCER: 351 return "sequencer"; 352 case SNDRV_DEVICE_TYPE_TIMER: 353 return "timer"; 354 default: 355 return "?"; 356 } 357 } 358 359 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer) 360 { 361 int minor; 362 struct snd_minor *mptr; 363 364 mutex_lock(&sound_mutex); 365 for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) { 366 if (!(mptr = snd_minors[minor])) 367 continue; 368 if (mptr->card >= 0) { 369 if (mptr->device >= 0) 370 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n", 371 minor, mptr->card, mptr->device, 372 snd_device_type_name(mptr->type)); 373 else 374 snd_iprintf(buffer, "%3i: [%2i] : %s\n", 375 minor, mptr->card, 376 snd_device_type_name(mptr->type)); 377 } else 378 snd_iprintf(buffer, "%3i: : %s\n", minor, 379 snd_device_type_name(mptr->type)); 380 } 381 mutex_unlock(&sound_mutex); 382 } 383 384 int __init snd_minor_info_init(void) 385 { 386 struct snd_info_entry *entry; 387 388 entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL); 389 if (!entry) 390 return -ENOMEM; 391 entry->c.text.read = snd_minor_info_read; 392 return snd_info_register(entry); /* freed in error path */ 393 } 394 #endif /* CONFIG_SND_PROC_FS */ 395 396 /* 397 * INIT PART 398 */ 399 400 static int __init alsa_sound_init(void) 401 { 402 snd_major = major; 403 snd_ecards_limit = cards_limit; 404 if (register_chrdev(major, "alsa", &snd_fops)) { 405 pr_err("ALSA core: unable to register native major device number %d\n", major); 406 return -EIO; 407 } 408 if (snd_info_init() < 0) { 409 unregister_chrdev(major, "alsa"); 410 return -ENOMEM; 411 } 412 #ifndef MODULE 413 pr_info("Advanced Linux Sound Architecture Driver Initialized.\n"); 414 #endif 415 return 0; 416 } 417 418 static void __exit alsa_sound_exit(void) 419 { 420 snd_info_done(); 421 unregister_chrdev(major, "alsa"); 422 } 423 424 subsys_initcall(alsa_sound_init); 425 module_exit(alsa_sound_exit); 426