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 struct snd_card *ref = snd_card_ref(card); 138 if (!ref) 139 snd_request_card(card); 140 else 141 snd_card_unref(ref); 142 } else if (dev == SNDRV_MINOR_GLOBAL) { 143 /* /dev/aloadSEQ */ 144 snd_request_other(minor); 145 } 146 mutex_lock(&sound_mutex); /* reacuire lock */ 147 return snd_minors[minor]; 148 } 149 #else /* !CONFIG_MODULES */ 150 #define autoload_device(minor) NULL 151 #endif /* CONFIG_MODULES */ 152 153 static int snd_open(struct inode *inode, struct file *file) 154 { 155 unsigned int minor = iminor(inode); 156 struct snd_minor *mptr = NULL; 157 const struct file_operations *new_fops; 158 int err = 0; 159 160 if (minor >= ARRAY_SIZE(snd_minors)) 161 return -ENODEV; 162 mutex_lock(&sound_mutex); 163 mptr = snd_minors[minor]; 164 if (mptr == NULL) { 165 mptr = autoload_device(minor); 166 if (!mptr) { 167 mutex_unlock(&sound_mutex); 168 return -ENODEV; 169 } 170 } 171 new_fops = fops_get(mptr->f_ops); 172 mutex_unlock(&sound_mutex); 173 if (!new_fops) 174 return -ENODEV; 175 replace_fops(file, new_fops); 176 177 if (file->f_op->open) 178 err = file->f_op->open(inode, file); 179 return err; 180 } 181 182 static const struct file_operations snd_fops = 183 { 184 .owner = THIS_MODULE, 185 .open = snd_open, 186 .llseek = noop_llseek, 187 }; 188 189 #ifdef CONFIG_SND_DYNAMIC_MINORS 190 static int snd_find_free_minor(int type, struct snd_card *card, int dev) 191 { 192 int minor; 193 194 /* static minors for module auto loading */ 195 if (type == SNDRV_DEVICE_TYPE_SEQUENCER) 196 return SNDRV_MINOR_SEQUENCER; 197 if (type == SNDRV_DEVICE_TYPE_TIMER) 198 return SNDRV_MINOR_TIMER; 199 200 for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) { 201 /* skip static minors still used for module auto loading */ 202 if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL) 203 continue; 204 if (minor == SNDRV_MINOR_SEQUENCER || 205 minor == SNDRV_MINOR_TIMER) 206 continue; 207 if (!snd_minors[minor]) 208 return minor; 209 } 210 return -EBUSY; 211 } 212 #else 213 static int snd_find_free_minor(int type, struct snd_card *card, int dev) 214 { 215 int minor; 216 217 switch (type) { 218 case SNDRV_DEVICE_TYPE_SEQUENCER: 219 case SNDRV_DEVICE_TYPE_TIMER: 220 minor = type; 221 break; 222 case SNDRV_DEVICE_TYPE_CONTROL: 223 if (snd_BUG_ON(!card)) 224 return -EINVAL; 225 minor = SNDRV_MINOR(card->number, type); 226 break; 227 case SNDRV_DEVICE_TYPE_HWDEP: 228 case SNDRV_DEVICE_TYPE_RAWMIDI: 229 case SNDRV_DEVICE_TYPE_PCM_PLAYBACK: 230 case SNDRV_DEVICE_TYPE_PCM_CAPTURE: 231 case SNDRV_DEVICE_TYPE_COMPRESS: 232 if (snd_BUG_ON(!card)) 233 return -EINVAL; 234 minor = SNDRV_MINOR(card->number, type + dev); 235 break; 236 default: 237 return -EINVAL; 238 } 239 if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS)) 240 return -EINVAL; 241 if (snd_minors[minor]) 242 return -EBUSY; 243 return minor; 244 } 245 #endif 246 247 /** 248 * snd_register_device - Register the ALSA device file for the card 249 * @type: the device type, SNDRV_DEVICE_TYPE_XXX 250 * @card: the card instance 251 * @dev: the device index 252 * @f_ops: the file operations 253 * @private_data: user pointer for f_ops->open() 254 * @device: the device to register 255 * 256 * Registers an ALSA device file for the given card. 257 * The operators have to be set in reg parameter. 258 * 259 * Return: Zero if successful, or a negative error code on failure. 260 */ 261 int snd_register_device(int type, struct snd_card *card, int dev, 262 const struct file_operations *f_ops, 263 void *private_data, struct device *device) 264 { 265 int minor; 266 int err = 0; 267 struct snd_minor *preg; 268 269 if (snd_BUG_ON(!device)) 270 return -EINVAL; 271 272 preg = kmalloc(sizeof *preg, GFP_KERNEL); 273 if (preg == NULL) 274 return -ENOMEM; 275 preg->type = type; 276 preg->card = card ? card->number : -1; 277 preg->device = dev; 278 preg->f_ops = f_ops; 279 preg->private_data = private_data; 280 preg->card_ptr = card; 281 mutex_lock(&sound_mutex); 282 minor = snd_find_free_minor(type, card, dev); 283 if (minor < 0) { 284 err = minor; 285 goto error; 286 } 287 288 preg->dev = device; 289 device->devt = MKDEV(major, minor); 290 err = device_add(device); 291 if (err < 0) 292 goto error; 293 294 snd_minors[minor] = preg; 295 error: 296 mutex_unlock(&sound_mutex); 297 if (err < 0) 298 kfree(preg); 299 return err; 300 } 301 EXPORT_SYMBOL(snd_register_device); 302 303 /** 304 * snd_unregister_device - unregister the device on the given card 305 * @dev: the device instance 306 * 307 * Unregisters the device file already registered via 308 * snd_register_device(). 309 * 310 * Return: Zero if successful, or a negative error code on failure. 311 */ 312 int snd_unregister_device(struct device *dev) 313 { 314 int minor; 315 struct snd_minor *preg; 316 317 mutex_lock(&sound_mutex); 318 for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) { 319 preg = snd_minors[minor]; 320 if (preg && preg->dev == dev) { 321 snd_minors[minor] = NULL; 322 device_del(dev); 323 kfree(preg); 324 break; 325 } 326 } 327 mutex_unlock(&sound_mutex); 328 if (minor >= ARRAY_SIZE(snd_minors)) 329 return -ENOENT; 330 return 0; 331 } 332 EXPORT_SYMBOL(snd_unregister_device); 333 334 #ifdef CONFIG_SND_PROC_FS 335 /* 336 * INFO PART 337 */ 338 static const char *snd_device_type_name(int type) 339 { 340 switch (type) { 341 case SNDRV_DEVICE_TYPE_CONTROL: 342 return "control"; 343 case SNDRV_DEVICE_TYPE_HWDEP: 344 return "hardware dependent"; 345 case SNDRV_DEVICE_TYPE_RAWMIDI: 346 return "raw midi"; 347 case SNDRV_DEVICE_TYPE_PCM_PLAYBACK: 348 return "digital audio playback"; 349 case SNDRV_DEVICE_TYPE_PCM_CAPTURE: 350 return "digital audio capture"; 351 case SNDRV_DEVICE_TYPE_SEQUENCER: 352 return "sequencer"; 353 case SNDRV_DEVICE_TYPE_TIMER: 354 return "timer"; 355 default: 356 return "?"; 357 } 358 } 359 360 static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer) 361 { 362 int minor; 363 struct snd_minor *mptr; 364 365 mutex_lock(&sound_mutex); 366 for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) { 367 if (!(mptr = snd_minors[minor])) 368 continue; 369 if (mptr->card >= 0) { 370 if (mptr->device >= 0) 371 snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n", 372 minor, mptr->card, mptr->device, 373 snd_device_type_name(mptr->type)); 374 else 375 snd_iprintf(buffer, "%3i: [%2i] : %s\n", 376 minor, mptr->card, 377 snd_device_type_name(mptr->type)); 378 } else 379 snd_iprintf(buffer, "%3i: : %s\n", minor, 380 snd_device_type_name(mptr->type)); 381 } 382 mutex_unlock(&sound_mutex); 383 } 384 385 int __init snd_minor_info_init(void) 386 { 387 struct snd_info_entry *entry; 388 389 entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL); 390 if (!entry) 391 return -ENOMEM; 392 entry->c.text.read = snd_minor_info_read; 393 return snd_info_register(entry); /* freed in error path */ 394 } 395 #endif /* CONFIG_SND_PROC_FS */ 396 397 /* 398 * INIT PART 399 */ 400 401 static int __init alsa_sound_init(void) 402 { 403 snd_major = major; 404 snd_ecards_limit = cards_limit; 405 if (register_chrdev(major, "alsa", &snd_fops)) { 406 pr_err("ALSA core: unable to register native major device number %d\n", major); 407 return -EIO; 408 } 409 if (snd_info_init() < 0) { 410 unregister_chrdev(major, "alsa"); 411 return -ENOMEM; 412 } 413 #ifndef MODULE 414 pr_info("Advanced Linux Sound Architecture Driver Initialized.\n"); 415 #endif 416 return 0; 417 } 418 419 static void __exit alsa_sound_exit(void) 420 { 421 snd_info_done(); 422 unregister_chrdev(major, "alsa"); 423 } 424 425 subsys_initcall(alsa_sound_init); 426 module_exit(alsa_sound_exit); 427