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 EXPORT_SYMBOL(snd_request_card); 78 79 static void snd_request_other(int minor) 80 { 81 char *str; 82 83 switch (minor) { 84 case SNDRV_MINOR_SEQUENCER: str = "snd-seq"; break; 85 case SNDRV_MINOR_TIMER: str = "snd-timer"; break; 86 default: return; 87 } 88 request_module(str); 89 } 90 91 #endif /* modular kernel */ 92 93 /** 94 * snd_lookup_minor_data - get user data of a registered device 95 * @minor: the minor number 96 * @type: device type (SNDRV_DEVICE_TYPE_XXX) 97 * 98 * Checks that a minor device with the specified type is registered, and returns 99 * its user data pointer. 100 * 101 * This function increments the reference counter of the card instance 102 * if an associated instance with the given minor number and type is found. 103 * The caller must call snd_card_unref() appropriately later. 104 * 105 * Return: The user data pointer if the specified device is found. %NULL 106 * otherwise. 107 */ 108 void *snd_lookup_minor_data(unsigned int minor, int type) 109 { 110 struct snd_minor *mreg; 111 void *private_data; 112 113 if (minor >= ARRAY_SIZE(snd_minors)) 114 return NULL; 115 mutex_lock(&sound_mutex); 116 mreg = snd_minors[minor]; 117 if (mreg && mreg->type == type) { 118 private_data = mreg->private_data; 119 if (private_data && mreg->card_ptr) 120 get_device(&mreg->card_ptr->card_dev); 121 } else 122 private_data = NULL; 123 mutex_unlock(&sound_mutex); 124 return private_data; 125 } 126 EXPORT_SYMBOL(snd_lookup_minor_data); 127 128 #ifdef CONFIG_MODULES 129 static struct snd_minor *autoload_device(unsigned int minor) 130 { 131 int dev; 132 mutex_unlock(&sound_mutex); /* release lock temporarily */ 133 dev = SNDRV_MINOR_DEVICE(minor); 134 if (dev == SNDRV_MINOR_CONTROL) { 135 /* /dev/aloadC? */ 136 int card = SNDRV_MINOR_CARD(minor); 137 if (snd_cards[card] == NULL) 138 snd_request_card(card); 139 } else if (dev == SNDRV_MINOR_GLOBAL) { 140 /* /dev/aloadSEQ */ 141 snd_request_other(minor); 142 } 143 mutex_lock(&sound_mutex); /* reacuire lock */ 144 return snd_minors[minor]; 145 } 146 #else /* !CONFIG_MODULES */ 147 #define autoload_device(minor) NULL 148 #endif /* CONFIG_MODULES */ 149 150 static int snd_open(struct inode *inode, struct file *file) 151 { 152 unsigned int minor = iminor(inode); 153 struct snd_minor *mptr = NULL; 154 const struct file_operations *new_fops; 155 int err = 0; 156 157 if (minor >= ARRAY_SIZE(snd_minors)) 158 return -ENODEV; 159 mutex_lock(&sound_mutex); 160 mptr = snd_minors[minor]; 161 if (mptr == NULL) { 162 mptr = autoload_device(minor); 163 if (!mptr) { 164 mutex_unlock(&sound_mutex); 165 return -ENODEV; 166 } 167 } 168 new_fops = fops_get(mptr->f_ops); 169 mutex_unlock(&sound_mutex); 170 if (!new_fops) 171 return -ENODEV; 172 replace_fops(file, new_fops); 173 174 if (file->f_op->open) 175 err = file->f_op->open(inode, file); 176 return err; 177 } 178 179 static const struct file_operations snd_fops = 180 { 181 .owner = THIS_MODULE, 182 .open = snd_open, 183 .llseek = noop_llseek, 184 }; 185 186 #ifdef CONFIG_SND_DYNAMIC_MINORS 187 static int snd_find_free_minor(int type, struct snd_card *card, int dev) 188 { 189 int minor; 190 191 /* static minors for module auto loading */ 192 if (type == SNDRV_DEVICE_TYPE_SEQUENCER) 193 return SNDRV_MINOR_SEQUENCER; 194 if (type == SNDRV_DEVICE_TYPE_TIMER) 195 return SNDRV_MINOR_TIMER; 196 197 for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) { 198 /* skip static minors still used for module auto loading */ 199 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL) 200 continue; 201 if (minor == SNDRV_MINOR_SEQUENCER || 202 minor == SNDRV_MINOR_TIMER) 203 continue; 204 if (!snd_minors[minor]) 205 return minor; 206 } 207 return -EBUSY; 208 } 209 #else 210 static int snd_find_free_minor(int type, struct snd_card *card, int dev) 211 { 212 int minor; 213 214 switch (type) { 215 case SNDRV_DEVICE_TYPE_SEQUENCER: 216 case SNDRV_DEVICE_TYPE_TIMER: 217 minor = type; 218 break; 219 case SNDRV_DEVICE_TYPE_CONTROL: 220 if (snd_BUG_ON(!card)) 221 return -EINVAL; 222 minor = SNDRV_MINOR(card->number, type); 223 break; 224 case SNDRV_DEVICE_TYPE_HWDEP: 225 case SNDRV_DEVICE_TYPE_RAWMIDI: 226 case SNDRV_DEVICE_TYPE_PCM_PLAYBACK: 227 case SNDRV_DEVICE_TYPE_PCM_CAPTURE: 228 case SNDRV_DEVICE_TYPE_COMPRESS: 229 if (snd_BUG_ON(!card)) 230 return -EINVAL; 231 minor = SNDRV_MINOR(card->number, type + dev); 232 break; 233 default: 234 return -EINVAL; 235 } 236 if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS)) 237 return -EINVAL; 238 if (snd_minors[minor]) 239 return -EBUSY; 240 return minor; 241 } 242 #endif 243 244 /** 245 * snd_register_device - Register the ALSA device file for the card 246 * @type: the device type, SNDRV_DEVICE_TYPE_XXX 247 * @card: the card instance 248 * @dev: the device index 249 * @f_ops: the file operations 250 * @private_data: user pointer for f_ops->open() 251 * @device: the device to register 252 * 253 * Registers an ALSA device file for the given card. 254 * The operators have to be set in reg parameter. 255 * 256 * Return: Zero if successful, or a negative error code on failure. 257 */ 258 int snd_register_device(int type, struct snd_card *card, int dev, 259 const struct file_operations *f_ops, 260 void *private_data, struct device *device) 261 { 262 int minor; 263 int err = 0; 264 struct snd_minor *preg; 265 266 if (snd_BUG_ON(!device)) 267 return -EINVAL; 268 269 preg = kmalloc(sizeof *preg, GFP_KERNEL); 270 if (preg == NULL) 271 return -ENOMEM; 272 preg->type = type; 273 preg->card = card ? card->number : -1; 274 preg->device = dev; 275 preg->f_ops = f_ops; 276 preg->private_data = private_data; 277 preg->card_ptr = card; 278 mutex_lock(&sound_mutex); 279 minor = snd_find_free_minor(type, card, dev); 280 if (minor < 0) { 281 err = minor; 282 goto error; 283 } 284 285 preg->dev = device; 286 device->devt = MKDEV(major, minor); 287 err = device_add(device); 288 if (err < 0) 289 goto error; 290 291 snd_minors[minor] = preg; 292 error: 293 mutex_unlock(&sound_mutex); 294 if (err < 0) 295 kfree(preg); 296 return err; 297 } 298 EXPORT_SYMBOL(snd_register_device); 299 300 /** 301 * snd_unregister_device - unregister the device on the given card 302 * @dev: the device instance 303 * 304 * Unregisters the device file already registered via 305 * snd_register_device(). 306 * 307 * Return: Zero if successful, or a negative error code on failure. 308 */ 309 int snd_unregister_device(struct device *dev) 310 { 311 int minor; 312 struct snd_minor *preg; 313 314 mutex_lock(&sound_mutex); 315 for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) { 316 preg = snd_minors[minor]; 317 if (preg && preg->dev == dev) { 318 snd_minors[minor] = NULL; 319 device_del(dev); 320 kfree(preg); 321 break; 322 } 323 } 324 mutex_unlock(&sound_mutex); 325 if (minor >= ARRAY_SIZE(snd_minors)) 326 return -ENOENT; 327 return 0; 328 } 329 EXPORT_SYMBOL(snd_unregister_device); 330 331 #ifdef CONFIG_SND_PROC_FS 332 /* 333 * INFO PART 334 */ 335 static const char *snd_device_type_name(int type) 336 { 337 switch (type) { 338 case SNDRV_DEVICE_TYPE_CONTROL: 339 return "control"; 340 case SNDRV_DEVICE_TYPE_HWDEP: 341 return "hardware dependent"; 342 case SNDRV_DEVICE_TYPE_RAWMIDI: 343 return "raw midi"; 344 case SNDRV_DEVICE_TYPE_PCM_PLAYBACK: 345 return "digital audio playback"; 346 case SNDRV_DEVICE_TYPE_PCM_CAPTURE: 347 return "digital audio capture"; 348 case SNDRV_DEVICE_TYPE_SEQUENCER: 349 return "sequencer"; 350 case SNDRV_DEVICE_TYPE_TIMER: 351 return "timer"; 352 default: 353 return "?"; 354 } 355 } 356 357 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer) 358 { 359 int minor; 360 struct snd_minor *mptr; 361 362 mutex_lock(&sound_mutex); 363 for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) { 364 if (!(mptr = snd_minors[minor])) 365 continue; 366 if (mptr->card >= 0) { 367 if (mptr->device >= 0) 368 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n", 369 minor, mptr->card, mptr->device, 370 snd_device_type_name(mptr->type)); 371 else 372 snd_iprintf(buffer, "%3i: [%2i] : %s\n", 373 minor, mptr->card, 374 snd_device_type_name(mptr->type)); 375 } else 376 snd_iprintf(buffer, "%3i: : %s\n", minor, 377 snd_device_type_name(mptr->type)); 378 } 379 mutex_unlock(&sound_mutex); 380 } 381 382 int __init snd_minor_info_init(void) 383 { 384 struct snd_info_entry *entry; 385 386 entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL); 387 if (!entry) 388 return -ENOMEM; 389 entry->c.text.read = snd_minor_info_read; 390 return snd_info_register(entry); /* freed in error path */ 391 } 392 #endif /* CONFIG_SND_PROC_FS */ 393 394 /* 395 * INIT PART 396 */ 397 398 static int __init alsa_sound_init(void) 399 { 400 snd_major = major; 401 snd_ecards_limit = cards_limit; 402 if (register_chrdev(major, "alsa", &snd_fops)) { 403 pr_err("ALSA core: unable to register native major device number %d\n", major); 404 return -EIO; 405 } 406 if (snd_info_init() < 0) { 407 unregister_chrdev(major, "alsa"); 408 return -ENOMEM; 409 } 410 #ifndef MODULE 411 pr_info("Advanced Linux Sound Architecture Driver Initialized.\n"); 412 #endif 413 return 0; 414 } 415 416 static void __exit alsa_sound_exit(void) 417 { 418 snd_info_done(); 419 unregister_chrdev(major, "alsa"); 420 } 421 422 subsys_initcall(alsa_sound_init); 423 module_exit(alsa_sound_exit); 424