sound/core/control.c

   1 /*
   2  *  Routines for driver control interface
   3  *  Copyright (c) by Jaroslav Kysela <perex@suse.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 <sound/driver.h>
  23 #include <linux/threads.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/slab.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/time.h>
  29 #include <sound/core.h>
  30 #include <sound/minors.h>
  31 #include <sound/info.h>
  32 #include <sound/control.h>
  33
  34 /* max number of user-defined controls */
  35 #define MAX_USER_CONTROLS       32
  36
  37 struct snd_kctl_ioctl {
  38         struct list_head list;          /* list of all ioctls */
  39         snd_kctl_ioctl_func_t fioctl;
  40 };
  41
  42 static DECLARE_RWSEM(snd_ioctl_rwsem);
  43 static LIST_HEAD(snd_control_ioctls);
  44 #ifdef CONFIG_COMPAT
  45 static LIST_HEAD(snd_control_compat_ioctls);
  46 #endif
  47
  48 static int snd_ctl_open(struct inode *inode, struct file *file)
  49 {
  50         int cardnum = SNDRV_MINOR_CARD(iminor(inode));
  51         unsigned long flags;
  52         struct snd_card *card;
  53         struct snd_ctl_file *ctl;
  54         int err;
  55
  56         card = snd_cards[cardnum];
  57         if (!card) {
  58                 err = -ENODEV;
  59                 goto __error1;
  60         }
  61         err = snd_card_file_add(card, file);
  62         if (err < 0) {
  63                 err = -ENODEV;
  64                 goto __error1;
  65         }
  66         if (!try_module_get(card->module)) {
  67                 err = -EFAULT;
  68                 goto __error2;
  69         }
  70         ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
  71         if (ctl == NULL) {
  72                 err = -ENOMEM;
  73                 goto __error;
  74         }
  75         INIT_LIST_HEAD(&ctl->events);
  76         init_waitqueue_head(&ctl->change_sleep);
  77         spin_lock_init(&ctl->read_lock);
  78         ctl->card = card;
  79         ctl->pid = current->pid;
  80         file->private_data = ctl;
  81         write_lock_irqsave(&card->ctl_files_rwlock, flags);
  82         list_add_tail(&ctl->list, &card->ctl_files);
  83         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
  84         return 0;
  85
  86       __error:
  87         module_put(card->module);
  88       __error2:
  89         snd_card_file_remove(card, file);
  90       __error1:
  91         return err;
  92 }
  93
  94 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
  95 {
  96         struct snd_kctl_event *cread;
  97
  98         spin_lock(&ctl->read_lock);
  99         while (!list_empty(&ctl->events)) {
 100                 cread = snd_kctl_event(ctl->events.next);
 101                 list_del(&cread->list);
 102                 kfree(cread);
 103         }
 104         spin_unlock(&ctl->read_lock);
 105 }
 106
 107 static int snd_ctl_release(struct inode *inode, struct file *file)
 108 {
 109         unsigned long flags;
 110         struct list_head *list;
 111         struct snd_card *card;
 112         struct snd_ctl_file *ctl;
 113         struct snd_kcontrol *control;
 114         unsigned int idx;
 115
 116         ctl = file->private_data;
 117         fasync_helper(-1, file, 0, &ctl->fasync);
 118         file->private_data = NULL;
 119         card = ctl->card;
 120         write_lock_irqsave(&card->ctl_files_rwlock, flags);
 121         list_del(&ctl->list);
 122         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 123         down_write(&card->controls_rwsem);
 124         list_for_each(list, &card->controls) {
 125                 control = snd_kcontrol(list);
 126                 for (idx = 0; idx < control->count; idx++)
 127                         if (control->vd[idx].owner == ctl)
 128                                 control->vd[idx].owner = NULL;
 129         }
 130         up_write(&card->controls_rwsem);
 131         snd_ctl_empty_read_queue(ctl);
 132         kfree(ctl);
 133         module_put(card->module);
 134         snd_card_file_remove(card, file);
 135         return 0;
 136 }
 137
 138 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 139                     struct snd_ctl_elem_id *id)
 140 {
 141         unsigned long flags;
 142         struct list_head *flist;
 143         struct snd_ctl_file *ctl;
 144         struct snd_kctl_event *ev;
 145
 146         snd_assert(card != NULL && id != NULL, return);
 147         read_lock(&card->ctl_files_rwlock);
 148 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 149         card->mixer_oss_change_count++;
 150 #endif
 151         list_for_each(flist, &card->ctl_files) {
 152                 struct list_head *elist;
 153                 ctl = snd_ctl_file(flist);
 154                 if (!ctl->subscribed)
 155                         continue;
 156                 spin_lock_irqsave(&ctl->read_lock, flags);
 157                 list_for_each(elist, &ctl->events) {
 158                         ev = snd_kctl_event(elist);
 159                         if (ev->id.numid == id->numid) {
 160                                 ev->mask |= mask;
 161                                 goto _found;
 162                         }
 163                 }
 164                 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
 165                 if (ev) {
 166                         ev->id = *id;
 167                         ev->mask = mask;
 168                         list_add_tail(&ev->list, &ctl->events);
 169                 } else {
 170                         snd_printk(KERN_ERR "No memory available to allocate event\n");
 171                 }
 172         _found:
 173                 wake_up(&ctl->change_sleep);
 174                 spin_unlock_irqrestore(&ctl->read_lock, flags);
 175                 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
 176         }
 177         read_unlock(&card->ctl_files_rwlock);
 178 }
 179
 180 /**
 181  * snd_ctl_new - create a control instance from the template
 182  * @control: the control template
 183  * @access: the default control access
 184  *
 185  * Allocates a new struct snd_kcontrol instance and copies the given template
 186  * to the new instance. It does not copy volatile data (access).
 187  *
 188  * Returns the pointer of the new instance, or NULL on failure.
 189  */
 190 struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control, unsigned int access)
 191 {
 192         struct snd_kcontrol *kctl;
 193         unsigned int idx;
 194
 195         snd_assert(control != NULL, return NULL);
 196         snd_assert(control->count > 0, return NULL);
 197         kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL);
 198         if (kctl == NULL) {
 199                 snd_printk(KERN_ERR "Cannot allocate control instance\n");
 200                 return NULL;
 201         }
 202         *kctl = *control;
 203         for (idx = 0; idx < kctl->count; idx++)
 204                 kctl->vd[idx].access = access;
 205         return kctl;
 206 }
 207
 208 /**
 209  * snd_ctl_new1 - create a control instance from the template
 210  * @ncontrol: the initialization record
 211  * @private_data: the private data to set
 212  *
 213  * Allocates a new struct snd_kcontrol instance and initialize from the given
 214  * template.  When the access field of ncontrol is 0, it's assumed as
 215  * READWRITE access. When the count field is 0, it's assumes as one.
 216  *
 217  * Returns the pointer of the newly generated instance, or NULL on failure.
 218  */
 219 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
 220                                   void *private_data)
 221 {
 222         struct snd_kcontrol kctl;
 223         unsigned int access;
 224
 225         snd_assert(ncontrol != NULL, return NULL);
 226         snd_assert(ncontrol->info != NULL, return NULL);
 227         memset(&kctl, 0, sizeof(kctl));
 228         kctl.id.iface = ncontrol->iface;
 229         kctl.id.device = ncontrol->device;
 230         kctl.id.subdevice = ncontrol->subdevice;
 231         if (ncontrol->name)
 232                 strlcpy(kctl.id.name, ncontrol->name, sizeof(kctl.id.name));
 233         kctl.id.index = ncontrol->index;
 234         kctl.count = ncontrol->count ? ncontrol->count : 1;
 235         access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
 236                  (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|SNDRV_CTL_ELEM_ACCESS_INACTIVE|
 237                                       SNDRV_CTL_ELEM_ACCESS_DINDIRECT|SNDRV_CTL_ELEM_ACCESS_INDIRECT));
 238         kctl.info = ncontrol->info;
 239         kctl.get = ncontrol->get;
 240         kctl.put = ncontrol->put;
 241         kctl.private_value = ncontrol->private_value;
 242         kctl.private_data = private_data;
 243         return snd_ctl_new(&kctl, access);
 244 }
 245
 246 /**
 247  * snd_ctl_free_one - release the control instance
 248  * @kcontrol: the control instance
 249  *
 250  * Releases the control instance created via snd_ctl_new()
 251  * or snd_ctl_new1().
 252  * Don't call this after the control was added to the card.
 253  */
 254 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
 255 {
 256         if (kcontrol) {
 257                 if (kcontrol->private_free)
 258                         kcontrol->private_free(kcontrol);
 259                 kfree(kcontrol);
 260         }
 261 }
 262
 263 static unsigned int snd_ctl_hole_check(struct snd_card *card,
 264                                        unsigned int count)
 265 {
 266         struct list_head *list;
 267         struct snd_kcontrol *kctl;
 268
 269         list_for_each(list, &card->controls) {
 270                 kctl = snd_kcontrol(list);
 271                 if ((kctl->id.numid <= card->last_numid &&
 272                      kctl->id.numid + kctl->count > card->last_numid) ||
 273                     (kctl->id.numid <= card->last_numid + count - 1 &&
 274                      kctl->id.numid + kctl->count > card->last_numid + count - 1))
 275                         return card->last_numid = kctl->id.numid + kctl->count - 1;
 276         }
 277         return card->last_numid;
 278 }
 279
 280 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 281 {
 282         unsigned int last_numid, iter = 100000;
 283
 284         last_numid = card->last_numid;
 285         while (last_numid != snd_ctl_hole_check(card, count)) {
 286                 if (--iter == 0) {
 287                         /* this situation is very unlikely */
 288                         snd_printk(KERN_ERR "unable to allocate new control numid\n");
 289                         return -ENOMEM;
 290                 }
 291                 last_numid = card->last_numid;
 292         }
 293         return 0;
 294 }
 295
 296 /**
 297  * snd_ctl_add - add the control instance to the card
 298  * @card: the card instance
 299  * @kcontrol: the control instance to add
 300  *
 301  * Adds the control instance created via snd_ctl_new() or
 302  * snd_ctl_new1() to the given card. Assigns also an unique
 303  * numid used for fast search.
 304  *
 305  * Returns zero if successful, or a negative error code on failure.
 306  *
 307  * It frees automatically the control which cannot be added.
 308  */
 309 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 310 {
 311         struct snd_ctl_elem_id id;
 312         unsigned int idx;
 313
 314         snd_assert(card != NULL, return -EINVAL);
 315         if (! kcontrol)
 316                 return -EINVAL;
 317         snd_assert(kcontrol->info != NULL, return -EINVAL);
 318         id = kcontrol->id;
 319         down_write(&card->controls_rwsem);
 320         if (snd_ctl_find_id(card, &id)) {
 321                 up_write(&card->controls_rwsem);
 322                 snd_ctl_free_one(kcontrol);
 323                 snd_printd(KERN_ERR "control %i:%i:%i:%s:%i is already present\n",
 324                                         id.iface,
 325                                         id.device,
 326                                         id.subdevice,
 327                                         id.name,
 328                                         id.index);
 329                 return -EBUSY;
 330         }
 331         if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 332                 up_write(&card->controls_rwsem);
 333                 snd_ctl_free_one(kcontrol);
 334                 return -ENOMEM;
 335         }
 336         list_add_tail(&kcontrol->list, &card->controls);
 337         card->controls_count += kcontrol->count;
 338         kcontrol->id.numid = card->last_numid + 1;
 339         card->last_numid += kcontrol->count;
 340         up_write(&card->controls_rwsem);
 341         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 342                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 343         return 0;
 344 }
 345
 346 /**
 347  * snd_ctl_remove - remove the control from the card and release it
 348  * @card: the card instance
 349  * @kcontrol: the control instance to remove
 350  *
 351  * Removes the control from the card and then releases the instance.
 352  * You don't need to call snd_ctl_free_one(). You must be in
 353  * the write lock - down_write(&card->controls_rwsem).
 354  *
 355  * Returns 0 if successful, or a negative error code on failure.
 356  */
 357 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 358 {
 359         struct snd_ctl_elem_id id;
 360         unsigned int idx;
 361
 362         snd_assert(card != NULL && kcontrol != NULL, return -EINVAL);
 363         list_del(&kcontrol->list);
 364         card->controls_count -= kcontrol->count;
 365         id = kcontrol->id;
 366         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 367                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
 368         snd_ctl_free_one(kcontrol);
 369         return 0;
 370 }
 371
 372 /**
 373  * snd_ctl_remove_id - remove the control of the given id and release it
 374  * @card: the card instance
 375  * @id: the control id to remove
 376  *
 377  * Finds the control instance with the given id, removes it from the
 378  * card list and releases it.
 379  *
 380  * Returns 0 if successful, or a negative error code on failure.
 381  */
 382 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 383 {
 384         struct snd_kcontrol *kctl;
 385         int ret;
 386
 387         down_write(&card->controls_rwsem);
 388         kctl = snd_ctl_find_id(card, id);
 389         if (kctl == NULL) {
 390                 up_write(&card->controls_rwsem);
 391                 return -ENOENT;
 392         }
 393         ret = snd_ctl_remove(card, kctl);
 394         up_write(&card->controls_rwsem);
 395         return ret;
 396 }
 397
 398 /**
 399  * snd_ctl_remove_unlocked_id - remove the unlocked control of the given id and release it
 400  * @file: active control handle
 401  * @id: the control id to remove
 402  *
 403  * Finds the control instance with the given id, removes it from the
 404  * card list and releases it.
 405  *
 406  * Returns 0 if successful, or a negative error code on failure.
 407  */
 408 static int snd_ctl_remove_unlocked_id(struct snd_ctl_file * file,
 409                                       struct snd_ctl_elem_id *id)
 410 {
 411         struct snd_card *card = file->card;
 412         struct snd_kcontrol *kctl;
 413         int idx, ret;
 414
 415         down_write(&card->controls_rwsem);
 416         kctl = snd_ctl_find_id(card, id);
 417         if (kctl == NULL) {
 418                 up_write(&card->controls_rwsem);
 419                 return -ENOENT;
 420         }
 421         for (idx = 0; idx < kctl->count; idx++)
 422                 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
 423                         up_write(&card->controls_rwsem);
 424                         return -EBUSY;
 425                 }
 426         ret = snd_ctl_remove(card, kctl);
 427         up_write(&card->controls_rwsem);
 428         return ret;
 429 }
 430
 431 /**
 432  * snd_ctl_rename_id - replace the id of a control on the card
 433  * @card: the card instance
 434  * @src_id: the old id
 435  * @dst_id: the new id
 436  *
 437  * Finds the control with the old id from the card, and replaces the
 438  * id with the new one.
 439  *
 440  * Returns zero if successful, or a negative error code on failure.
 441  */
 442 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 443                       struct snd_ctl_elem_id *dst_id)
 444 {
 445         struct snd_kcontrol *kctl;
 446
 447         down_write(&card->controls_rwsem);
 448         kctl = snd_ctl_find_id(card, src_id);
 449         if (kctl == NULL) {
 450                 up_write(&card->controls_rwsem);
 451                 return -ENOENT;
 452         }
 453         kctl->id = *dst_id;
 454         kctl->id.numid = card->last_numid + 1;
 455         card->last_numid += kctl->count;
 456         up_write(&card->controls_rwsem);
 457         return 0;
 458 }
 459
 460 /**
 461  * snd_ctl_find_numid - find the control instance with the given number-id
 462  * @card: the card instance
 463  * @numid: the number-id to search
 464  *
 465  * Finds the control instance with the given number-id from the card.
 466  *
 467  * Returns the pointer of the instance if found, or NULL if not.
 468  *
 469  * The caller must down card->controls_rwsem before calling this function
 470  * (if the race condition can happen).
 471  */
 472 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 473 {
 474         struct list_head *list;
 475         struct snd_kcontrol *kctl;
 476
 477         snd_assert(card != NULL && numid != 0, return NULL);
 478         list_for_each(list, &card->controls) {
 479                 kctl = snd_kcontrol(list);
 480                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 481                         return kctl;
 482         }
 483         return NULL;
 484 }
 485
 486 /**
 487  * snd_ctl_find_id - find the control instance with the given id
 488  * @card: the card instance
 489  * @id: the id to search
 490  *
 491  * Finds the control instance with the given id from the card.
 492  *
 493  * Returns the pointer of the instance if found, or NULL if not.
 494  *
 495  * The caller must down card->controls_rwsem before calling this function
 496  * (if the race condition can happen).
 497  */
 498 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 499                                      struct snd_ctl_elem_id *id)
 500 {
 501         struct list_head *list;
 502         struct snd_kcontrol *kctl;
 503
 504         snd_assert(card != NULL && id != NULL, return NULL);
 505         if (id->numid != 0)
 506                 return snd_ctl_find_numid(card, id->numid);
 507         list_for_each(list, &card->controls) {
 508                 kctl = snd_kcontrol(list);
 509                 if (kctl->id.iface != id->iface)
 510                         continue;
 511                 if (kctl->id.device != id->device)
 512                         continue;
 513                 if (kctl->id.subdevice != id->subdevice)
 514                         continue;
 515                 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
 516                         continue;
 517                 if (kctl->id.index > id->index)
 518                         continue;
 519                 if (kctl->id.index + kctl->count <= id->index)
 520                         continue;
 521                 return kctl;
 522         }
 523         return NULL;
 524 }
 525
 526 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 527                              unsigned int cmd, void __user *arg)
 528 {
 529         struct snd_ctl_card_info *info;
 530
 531         info = kzalloc(sizeof(*info), GFP_KERNEL);
 532         if (! info)
 533                 return -ENOMEM;
 534         down_read(&snd_ioctl_rwsem);
 535         info->card = card->number;
 536         strlcpy(info->id, card->id, sizeof(info->id));
 537         strlcpy(info->driver, card->driver, sizeof(info->driver));
 538         strlcpy(info->name, card->shortname, sizeof(info->name));
 539         strlcpy(info->longname, card->longname, sizeof(info->longname));
 540         strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
 541         strlcpy(info->components, card->components, sizeof(info->components));
 542         up_read(&snd_ioctl_rwsem);
 543         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 544                 kfree(info);
 545                 return -EFAULT;
 546         }
 547         kfree(info);
 548         return 0;
 549 }
 550
 551 static int snd_ctl_elem_list(struct snd_card *card,
 552                              struct snd_ctl_elem_list __user *_list)
 553 {
 554         struct list_head *plist;
 555         struct snd_ctl_elem_list list;
 556         struct snd_kcontrol *kctl;
 557         struct snd_ctl_elem_id *dst, *id;
 558         unsigned int offset, space, first, jidx;
 559
 560         if (copy_from_user(&list, _list, sizeof(list)))
 561                 return -EFAULT;
 562         offset = list.offset;
 563         space = list.space;
 564         first = 0;
 565         /* try limit maximum space */
 566         if (space > 16384)
 567                 return -ENOMEM;
 568         if (space > 0) {
 569                 /* allocate temporary buffer for atomic operation */
 570                 dst = vmalloc(space * sizeof(struct snd_ctl_elem_id));
 571                 if (dst == NULL)
 572                         return -ENOMEM;
 573                 down_read(&card->controls_rwsem);
 574                 list.count = card->controls_count;
 575                 plist = card->controls.next;
 576                 while (plist != &card->controls) {
 577                         if (offset == 0)
 578                                 break;
 579                         kctl = snd_kcontrol(plist);
 580                         if (offset < kctl->count)
 581                                 break;
 582                         offset -= kctl->count;
 583                         plist = plist->next;
 584                 }
 585                 list.used = 0;
 586                 id = dst;
 587                 while (space > 0 && plist != &card->controls) {
 588                         kctl = snd_kcontrol(plist);
 589                         for (jidx = offset; space > 0 && jidx < kctl->count; jidx++) {
 590                                 snd_ctl_build_ioff(id, kctl, jidx);
 591                                 id++;
 592                                 space--;
 593                                 list.used++;
 594                         }
 595                         plist = plist->next;
 596                         offset = 0;
 597                 }
 598                 up_read(&card->controls_rwsem);
 599                 if (list.used > 0 &&
 600                     copy_to_user(list.pids, dst,
 601                                  list.used * sizeof(struct snd_ctl_elem_id))) {
 602                         vfree(dst);
 603                         return -EFAULT;
 604                 }
 605                 vfree(dst);
 606         } else {
 607                 down_read(&card->controls_rwsem);
 608                 list.count = card->controls_count;
 609                 up_read(&card->controls_rwsem);
 610         }
 611         if (copy_to_user(_list, &list, sizeof(list)))
 612                 return -EFAULT;
 613         return 0;
 614 }
 615
 616 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 617                              struct snd_ctl_elem_info *info)
 618 {
 619         struct snd_card *card = ctl->card;
 620         struct snd_kcontrol *kctl;
 621         struct snd_kcontrol_volatile *vd;
 622         unsigned int index_offset;
 623         int result;
 624
 625         down_read(&card->controls_rwsem);
 626         kctl = snd_ctl_find_id(card, &info->id);
 627         if (kctl == NULL) {
 628                 up_read(&card->controls_rwsem);
 629                 return -ENOENT;
 630         }
 631 #ifdef CONFIG_SND_DEBUG
 632         info->access = 0;
 633 #endif
 634         result = kctl->info(kctl, info);
 635         if (result >= 0) {
 636                 snd_assert(info->access == 0, );
 637                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
 638                 vd = &kctl->vd[index_offset];
 639                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
 640                 info->access = vd->access;
 641                 if (vd->owner) {
 642                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
 643                         if (vd->owner == ctl)
 644                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
 645                         info->owner = vd->owner_pid;
 646                 } else {
 647                         info->owner = -1;
 648                 }
 649         }
 650         up_read(&card->controls_rwsem);
 651         return result;
 652 }
 653
 654 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
 655                                   struct snd_ctl_elem_info __user *_info)
 656 {
 657         struct snd_ctl_elem_info info;
 658         int result;
 659
 660         if (copy_from_user(&info, _info, sizeof(info)))
 661                 return -EFAULT;
 662         result = snd_ctl_elem_info(ctl, &info);
 663         if (result >= 0)
 664                 if (copy_to_user(_info, &info, sizeof(info)))
 665                         return -EFAULT;
 666         return result;
 667 }
 668
 669 int snd_ctl_elem_read(struct snd_card *card, struct snd_ctl_elem_value *control)
 670 {
 671         struct snd_kcontrol *kctl;
 672         struct snd_kcontrol_volatile *vd;
 673         unsigned int index_offset;
 674         int result, indirect;
 675
 676         down_read(&card->controls_rwsem);
 677         kctl = snd_ctl_find_id(card, &control->id);
 678         if (kctl == NULL) {
 679                 result = -ENOENT;
 680         } else {
 681                 index_offset = snd_ctl_get_ioff(kctl, &control->id);
 682                 vd = &kctl->vd[index_offset];
 683                 indirect = vd->access & SNDRV_CTL_ELEM_ACCESS_INDIRECT ? 1 : 0;
 684                 if (control->indirect != indirect) {
 685                         result = -EACCES;
 686                 } else {
 687                         if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) && kctl->get != NULL) {
 688                                 snd_ctl_build_ioff(&control->id, kctl, index_offset);
 689                                 result = kctl->get(kctl, control);
 690                         } else {
 691                                 result = -EPERM;
 692                         }
 693                 }
 694         }
 695         up_read(&card->controls_rwsem);
 696         return result;
 697 }
 698
 699 static int snd_ctl_elem_read_user(struct snd_card *card,
 700                                   struct snd_ctl_elem_value __user *_control)
 701 {
 702         struct snd_ctl_elem_value *control;
 703         int result;
 704
 705         control = kmalloc(sizeof(*control), GFP_KERNEL);
 706         if (control == NULL)
 707                 return -ENOMEM;
 708         if (copy_from_user(control, _control, sizeof(*control))) {
 709                 kfree(control);
 710                 return -EFAULT;
 711         }
 712         result = snd_ctl_elem_read(card, control);
 713         if (result >= 0)
 714                 if (copy_to_user(_control, control, sizeof(*control)))
 715                         result = -EFAULT;
 716         kfree(control);
 717         return result;
 718 }
 719
 720 int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
 721                        struct snd_ctl_elem_value *control)
 722 {
 723         struct snd_kcontrol *kctl;
 724         struct snd_kcontrol_volatile *vd;
 725         unsigned int index_offset;
 726         int result, indirect;
 727
 728         down_read(&card->controls_rwsem);
 729         kctl = snd_ctl_find_id(card, &control->id);
 730         if (kctl == NULL) {
 731                 result = -ENOENT;
 732         } else {
 733                 index_offset = snd_ctl_get_ioff(kctl, &control->id);
 734                 vd = &kctl->vd[index_offset];
 735                 indirect = vd->access & SNDRV_CTL_ELEM_ACCESS_INDIRECT ? 1 : 0;
 736                 if (control->indirect != indirect) {
 737                         result = -EACCES;
 738                 } else {
 739                         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
 740                             kctl->put == NULL ||
 741                             (file && vd->owner != NULL && vd->owner != file)) {
 742                                 result = -EPERM;
 743                         } else {
 744                                 snd_ctl_build_ioff(&control->id, kctl, index_offset);
 745                                 result = kctl->put(kctl, control);
 746                         }
 747                         if (result > 0) {
 748                                 up_read(&card->controls_rwsem);
 749                                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &control->id);
 750                                 return 0;
 751                         }
 752                 }
 753         }
 754         up_read(&card->controls_rwsem);
 755         return result;
 756 }
 757
 758 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
 759                                    struct snd_ctl_elem_value __user *_control)
 760 {
 761         struct snd_ctl_elem_value *control;
 762         int result;
 763
 764         control = kmalloc(sizeof(*control), GFP_KERNEL);
 765         if (control == NULL)
 766                 return -ENOMEM;
 767         if (copy_from_user(control, _control, sizeof(*control))) {
 768                 kfree(control);
 769                 return -EFAULT;
 770         }
 771         result = snd_ctl_elem_write(file->card, file, control);
 772         if (result >= 0)
 773                 if (copy_to_user(_control, control, sizeof(*control)))
 774                         result = -EFAULT;
 775         kfree(control);
 776         return result;
 777 }
 778
 779 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
 780                              struct snd_ctl_elem_id __user *_id)
 781 {
 782         struct snd_card *card = file->card;
 783         struct snd_ctl_elem_id id;
 784         struct snd_kcontrol *kctl;
 785         struct snd_kcontrol_volatile *vd;
 786         int result;
 787
 788         if (copy_from_user(&id, _id, sizeof(id)))
 789                 return -EFAULT;
 790         down_write(&card->controls_rwsem);
 791         kctl = snd_ctl_find_id(card, &id);
 792         if (kctl == NULL) {
 793                 result = -ENOENT;
 794         } else {
 795                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
 796                 if (vd->owner != NULL)
 797                         result = -EBUSY;
 798                 else {
 799                         vd->owner = file;
 800                         vd->owner_pid = current->pid;
 801                         result = 0;
 802                 }
 803         }
 804         up_write(&card->controls_rwsem);
 805         return result;
 806 }
 807
 808 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
 809                                struct snd_ctl_elem_id __user *_id)
 810 {
 811         struct snd_card *card = file->card;
 812         struct snd_ctl_elem_id id;
 813         struct snd_kcontrol *kctl;
 814         struct snd_kcontrol_volatile *vd;
 815         int result;
 816
 817         if (copy_from_user(&id, _id, sizeof(id)))
 818                 return -EFAULT;
 819         down_write(&card->controls_rwsem);
 820         kctl = snd_ctl_find_id(card, &id);
 821         if (kctl == NULL) {
 822                 result = -ENOENT;
 823         } else {
 824                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
 825                 if (vd->owner == NULL)
 826                         result = -EINVAL;
 827                 else if (vd->owner != file)
 828                         result = -EPERM;
 829                 else {
 830                         vd->owner = NULL;
 831                         vd->owner_pid = 0;
 832                         result = 0;
 833                 }
 834         }
 835         up_write(&card->controls_rwsem);
 836         return result;
 837 }
 838
 839 struct user_element {
 840         struct snd_ctl_elem_info info;
 841         void *elem_data;                /* element data */
 842         unsigned long elem_data_size;   /* size of element data in bytes */
 843         void *priv_data;                /* private data (like strings for enumerated type) */
 844         unsigned long priv_data_size;   /* size of private data in bytes */
 845 };
 846
 847 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
 848                                   struct snd_ctl_elem_info *uinfo)
 849 {
 850         struct user_element *ue = kcontrol->private_data;
 851
 852         *uinfo = ue->info;
 853         return 0;
 854 }
 855
 856 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
 857                                  struct snd_ctl_elem_value *ucontrol)
 858 {
 859         struct user_element *ue = kcontrol->private_data;
 860
 861         memcpy(&ucontrol->value, ue->elem_data, ue->elem_data_size);
 862         return 0;
 863 }
 864
 865 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
 866                                  struct snd_ctl_elem_value *ucontrol)
 867 {
 868         int change;
 869         struct user_element *ue = kcontrol->private_data;
 870
 871         change = memcmp(&ucontrol->value, ue->elem_data, ue->elem_data_size) != 0;
 872         if (change)
 873                 memcpy(ue->elem_data, &ucontrol->value, ue->elem_data_size);
 874         return change;
 875 }
 876
 877 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
 878 {
 879         kfree(kcontrol->private_data);
 880 }
 881
 882 static int snd_ctl_elem_add(struct snd_ctl_file *file,
 883                             struct snd_ctl_elem_info *info, int replace)
 884 {
 885         struct snd_card *card = file->card;
 886         struct snd_kcontrol kctl, *_kctl;
 887         unsigned int access;
 888         long private_size;
 889         struct user_element *ue;
 890         int idx, err;
 891
 892         if (card->user_ctl_count >= MAX_USER_CONTROLS)
 893                 return -ENOMEM;
 894         if (info->count > 1024)
 895                 return -EINVAL;
 896         access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
 897                 (info->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
 898                                  SNDRV_CTL_ELEM_ACCESS_INACTIVE));
 899         info->id.numid = 0;
 900         memset(&kctl, 0, sizeof(kctl));
 901         down_write(&card->controls_rwsem);
 902         _kctl = snd_ctl_find_id(card, &info->id);
 903         err = 0;
 904         if (_kctl) {
 905                 if (replace)
 906                         err = snd_ctl_remove(card, _kctl);
 907                 else
 908                         err = -EBUSY;
 909         } else {
 910                 if (replace)
 911                         err = -ENOENT;
 912         }
 913         up_write(&card->controls_rwsem);
 914         if (err < 0)
 915                 return err;
 916         memcpy(&kctl.id, &info->id, sizeof(info->id));
 917         kctl.count = info->owner ? info->owner : 1;
 918         access |= SNDRV_CTL_ELEM_ACCESS_USER;
 919         kctl.info = snd_ctl_elem_user_info;
 920         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
 921                 kctl.get = snd_ctl_elem_user_get;
 922         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
 923                 kctl.put = snd_ctl_elem_user_put;
 924         switch (info->type) {
 925         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
 926                 private_size = sizeof(char);
 927                 if (info->count > 128)
 928                         return -EINVAL;
 929                 break;
 930         case SNDRV_CTL_ELEM_TYPE_INTEGER:
 931                 private_size = sizeof(long);
 932                 if (info->count > 128)
 933                         return -EINVAL;
 934                 break;
 935         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
 936                 private_size = sizeof(long long);
 937                 if (info->count > 64)
 938                         return -EINVAL;
 939                 break;
 940         case SNDRV_CTL_ELEM_TYPE_BYTES:
 941                 private_size = sizeof(unsigned char);
 942                 if (info->count > 512)
 943                         return -EINVAL;
 944                 break;
 945         case SNDRV_CTL_ELEM_TYPE_IEC958:
 946                 private_size = sizeof(struct snd_aes_iec958);
 947                 if (info->count != 1)
 948                         return -EINVAL;
 949                 break;
 950         default:
 951                 return -EINVAL;
 952         }
 953         private_size *= info->count;
 954         ue = kzalloc(sizeof(struct user_element) + private_size, GFP_KERNEL);
 955         if (ue == NULL)
 956                 return -ENOMEM;
 957         ue->info = *info;
 958         ue->elem_data = (char *)ue + sizeof(*ue);
 959         ue->elem_data_size = private_size;
 960         kctl.private_free = snd_ctl_elem_user_free;
 961         _kctl = snd_ctl_new(&kctl, access);
 962         if (_kctl == NULL) {
 963                 kfree(_kctl->private_data);
 964                 return -ENOMEM;
 965         }
 966         _kctl->private_data = ue;
 967         for (idx = 0; idx < _kctl->count; idx++)
 968                 _kctl->vd[idx].owner = file;
 969         err = snd_ctl_add(card, _kctl);
 970         if (err < 0) {
 971                 snd_ctl_free_one(_kctl);
 972                 return err;
 973         }
 974
 975         down_write(&card->controls_rwsem);
 976         card->user_ctl_count++;
 977         up_write(&card->controls_rwsem);
 978
 979         return 0;
 980 }
 981
 982 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
 983                                  struct snd_ctl_elem_info __user *_info, int replace)
 984 {
 985         struct snd_ctl_elem_info info;
 986         if (copy_from_user(&info, _info, sizeof(info)))
 987                 return -EFAULT;
 988         return snd_ctl_elem_add(file, &info, replace);
 989 }
 990
 991 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
 992                                struct snd_ctl_elem_id __user *_id)
 993 {
 994         struct snd_ctl_elem_id id;
 995         int err;
 996
 997         if (copy_from_user(&id, _id, sizeof(id)))
 998                 return -EFAULT;
 999         err = snd_ctl_remove_unlocked_id(file, &id);
1000         if (! err) {
1001                 struct snd_card *card = file->card;
1002                 down_write(&card->controls_rwsem);
1003                 card->user_ctl_count--;
1004                 up_write(&card->controls_rwsem);
1005         }
1006         return err;
1007 }
1008
1009 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1010 {
1011         int subscribe;
1012         if (get_user(subscribe, ptr))
1013                 return -EFAULT;
1014         if (subscribe < 0) {
1015                 subscribe = file->subscribed;
1016                 if (put_user(subscribe, ptr))
1017                         return -EFAULT;
1018                 return 0;
1019         }
1020         if (subscribe) {
1021                 file->subscribed = 1;
1022                 return 0;
1023         } else if (file->subscribed) {
1024                 snd_ctl_empty_read_queue(file);
1025                 file->subscribed = 0;
1026         }
1027         return 0;
1028 }
1029
1030 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1031 {
1032         struct snd_ctl_file *ctl;
1033         struct snd_card *card;
1034         struct list_head *list;
1035         struct snd_kctl_ioctl *p;
1036         void __user *argp = (void __user *)arg;
1037         int __user *ip = argp;
1038         int err;
1039
1040         ctl = file->private_data;
1041         card = ctl->card;
1042         snd_assert(card != NULL, return -ENXIO);
1043         switch (cmd) {
1044         case SNDRV_CTL_IOCTL_PVERSION:
1045                 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1046         case SNDRV_CTL_IOCTL_CARD_INFO:
1047                 return snd_ctl_card_info(card, ctl, cmd, argp);
1048         case SNDRV_CTL_IOCTL_ELEM_LIST:
1049                 return snd_ctl_elem_list(ctl->card, argp);
1050         case SNDRV_CTL_IOCTL_ELEM_INFO:
1051                 return snd_ctl_elem_info_user(ctl, argp);
1052         case SNDRV_CTL_IOCTL_ELEM_READ:
1053                 return snd_ctl_elem_read_user(ctl->card, argp);
1054         case SNDRV_CTL_IOCTL_ELEM_WRITE:
1055                 return snd_ctl_elem_write_user(ctl, argp);
1056         case SNDRV_CTL_IOCTL_ELEM_LOCK:
1057                 return snd_ctl_elem_lock(ctl, argp);
1058         case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1059                 return snd_ctl_elem_unlock(ctl, argp);
1060         case SNDRV_CTL_IOCTL_ELEM_ADD:
1061                 return snd_ctl_elem_add_user(ctl, argp, 0);
1062         case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1063                 return snd_ctl_elem_add_user(ctl, argp, 1);
1064         case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1065                 return snd_ctl_elem_remove(ctl, argp);
1066         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1067                 return snd_ctl_subscribe_events(ctl, ip);
1068         case SNDRV_CTL_IOCTL_POWER:
1069                 return -ENOPROTOOPT;
1070         case SNDRV_CTL_IOCTL_POWER_STATE:
1071 #ifdef CONFIG_PM
1072                 return put_user(card->power_state, ip) ? -EFAULT : 0;
1073 #else
1074                 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1075 #endif
1076         }
1077         down_read(&snd_ioctl_rwsem);
1078         list_for_each(list, &snd_control_ioctls) {
1079                 p = list_entry(list, struct snd_kctl_ioctl, list);
1080                 err = p->fioctl(card, ctl, cmd, arg);
1081                 if (err != -ENOIOCTLCMD) {
1082                         up_read(&snd_ioctl_rwsem);
1083                         return err;
1084                 }
1085         }
1086         up_read(&snd_ioctl_rwsem);
1087         snd_printdd("unknown ioctl = 0x%x\n", cmd);
1088         return -ENOTTY;
1089 }
1090
1091 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1092                             size_t count, loff_t * offset)
1093 {
1094         struct snd_ctl_file *ctl;
1095         int err = 0;
1096         ssize_t result = 0;
1097
1098         ctl = file->private_data;
1099         snd_assert(ctl != NULL && ctl->card != NULL, return -ENXIO);
1100         if (!ctl->subscribed)
1101                 return -EBADFD;
1102         if (count < sizeof(struct snd_ctl_event))
1103                 return -EINVAL;
1104         spin_lock_irq(&ctl->read_lock);
1105         while (count >= sizeof(struct snd_ctl_event)) {
1106                 struct snd_ctl_event ev;
1107                 struct snd_kctl_event *kev;
1108                 while (list_empty(&ctl->events)) {
1109                         wait_queue_t wait;
1110                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1111                                 err = -EAGAIN;
1112                                 goto __end_lock;
1113                         }
1114                         init_waitqueue_entry(&wait, current);
1115                         add_wait_queue(&ctl->change_sleep, &wait);
1116                         set_current_state(TASK_INTERRUPTIBLE);
1117                         spin_unlock_irq(&ctl->read_lock);
1118                         schedule();
1119                         remove_wait_queue(&ctl->change_sleep, &wait);
1120                         if (signal_pending(current))
1121                                 return result > 0 ? result : -ERESTARTSYS;
1122                         spin_lock_irq(&ctl->read_lock);
1123                 }
1124                 kev = snd_kctl_event(ctl->events.next);
1125                 ev.type = SNDRV_CTL_EVENT_ELEM;
1126                 ev.data.elem.mask = kev->mask;
1127                 ev.data.elem.id = kev->id;
1128                 list_del(&kev->list);
1129                 spin_unlock_irq(&ctl->read_lock);
1130                 kfree(kev);
1131                 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1132                         err = -EFAULT;
1133                         goto __end;
1134                 }
1135                 spin_lock_irq(&ctl->read_lock);
1136                 buffer += sizeof(struct snd_ctl_event);
1137                 count -= sizeof(struct snd_ctl_event);
1138                 result += sizeof(struct snd_ctl_event);
1139         }
1140       __end_lock:
1141         spin_unlock_irq(&ctl->read_lock);
1142       __end:
1143         return result > 0 ? result : err;
1144 }
1145
1146 static unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
1147 {
1148         unsigned int mask;
1149         struct snd_ctl_file *ctl;
1150
1151         ctl = file->private_data;
1152         if (!ctl->subscribed)
1153                 return 0;
1154         poll_wait(file, &ctl->change_sleep, wait);
1155
1156         mask = 0;
1157         if (!list_empty(&ctl->events))
1158                 mask |= POLLIN | POLLRDNORM;
1159
1160         return mask;
1161 }
1162
1163 /*
1164  * register the device-specific control-ioctls.
1165  * called from each device manager like pcm.c, hwdep.c, etc.
1166  */
1167 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1168 {
1169         struct snd_kctl_ioctl *pn;
1170
1171         pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1172         if (pn == NULL)
1173                 return -ENOMEM;
1174         pn->fioctl = fcn;
1175         down_write(&snd_ioctl_rwsem);
1176         list_add_tail(&pn->list, lists);
1177         up_write(&snd_ioctl_rwsem);
1178         return 0;
1179 }
1180
1181 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1182 {
1183         return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1184 }
1185
1186 #ifdef CONFIG_COMPAT
1187 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1188 {
1189         return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1190 }
1191 #endif
1192
1193 /*
1194  * de-register the device-specific control-ioctls.
1195  */
1196 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1197                                      struct list_head *lists)
1198 {
1199         struct list_head *list;
1200         struct snd_kctl_ioctl *p;
1201
1202         snd_assert(fcn != NULL, return -EINVAL);
1203         down_write(&snd_ioctl_rwsem);
1204         list_for_each(list, lists) {
1205                 p = list_entry(list, struct snd_kctl_ioctl, list);
1206                 if (p->fioctl == fcn) {
1207                         list_del(&p->list);
1208                         up_write(&snd_ioctl_rwsem);
1209                         kfree(p);
1210                         return 0;
1211                 }
1212         }
1213         up_write(&snd_ioctl_rwsem);
1214         snd_BUG();
1215         return -EINVAL;
1216 }
1217
1218 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1219 {
1220         return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1221 }
1222
1223 #ifdef CONFIG_COMPAT
1224 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1225 {
1226         return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1227 }
1228
1229 #endif
1230
1231 static int snd_ctl_fasync(int fd, struct file * file, int on)
1232 {
1233         struct snd_ctl_file *ctl;
1234         int err;
1235         ctl = file->private_data;
1236         err = fasync_helper(fd, file, on, &ctl->fasync);
1237         if (err < 0)
1238                 return err;
1239         return 0;
1240 }
1241
1242 /*
1243  * ioctl32 compat
1244  */
1245 #ifdef CONFIG_COMPAT
1246 #include "control_compat.c"
1247 #else
1248 #define snd_ctl_ioctl_compat    NULL
1249 #endif
1250
1251 /*
1252  *  INIT PART
1253  */
1254
1255 static struct file_operations snd_ctl_f_ops =
1256 {
1257         .owner =        THIS_MODULE,
1258         .read =         snd_ctl_read,
1259         .open =         snd_ctl_open,
1260         .release =      snd_ctl_release,
1261         .poll =         snd_ctl_poll,
1262         .unlocked_ioctl =       snd_ctl_ioctl,
1263         .compat_ioctl = snd_ctl_ioctl_compat,
1264         .fasync =       snd_ctl_fasync,
1265 };
1266
1267 static struct snd_minor snd_ctl_reg =
1268 {
1269         .comment =      "ctl",
1270         .f_ops =        &snd_ctl_f_ops,
1271 };
1272
1273 /*
1274  * registration of the control device
1275  */
1276 static int snd_ctl_dev_register(struct snd_device *device)
1277 {
1278         struct snd_card *card = device->device_data;
1279         int err, cardnum;
1280         char name[16];
1281
1282         snd_assert(card != NULL, return -ENXIO);
1283         cardnum = card->number;
1284         snd_assert(cardnum >= 0 && cardnum < SNDRV_CARDS, return -ENXIO);
1285         sprintf(name, "controlC%i", cardnum);
1286         if ((err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL,
1287                                         card, 0, &snd_ctl_reg, name)) < 0)
1288                 return err;
1289         return 0;
1290 }
1291
1292 /*
1293  * disconnection of the control device
1294  */
1295 static int snd_ctl_dev_disconnect(struct snd_device *device)
1296 {
1297         struct snd_card *card = device->device_data;
1298         struct list_head *flist;
1299         struct snd_ctl_file *ctl;
1300
1301         down_read(&card->controls_rwsem);
1302         list_for_each(flist, &card->ctl_files) {
1303                 ctl = snd_ctl_file(flist);
1304                 wake_up(&ctl->change_sleep);
1305                 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1306         }
1307         up_read(&card->controls_rwsem);
1308         return 0;
1309 }
1310
1311 /*
1312  * free all controls
1313  */
1314 static int snd_ctl_dev_free(struct snd_device *device)
1315 {
1316         struct snd_card *card = device->device_data;
1317         struct snd_kcontrol *control;
1318
1319         down_write(&card->controls_rwsem);
1320         while (!list_empty(&card->controls)) {
1321                 control = snd_kcontrol(card->controls.next);
1322                 snd_ctl_remove(card, control);
1323         }
1324         up_write(&card->controls_rwsem);
1325         return 0;
1326 }
1327
1328 /*
1329  * de-registration of the control device
1330  */
1331 static int snd_ctl_dev_unregister(struct snd_device *device)
1332 {
1333         struct snd_card *card = device->device_data;
1334         int err, cardnum;
1335
1336         snd_assert(card != NULL, return -ENXIO);
1337         cardnum = card->number;
1338         snd_assert(cardnum >= 0 && cardnum < SNDRV_CARDS, return -ENXIO);
1339         if ((err = snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL, card, 0)) < 0)
1340                 return err;
1341         return snd_ctl_dev_free(device);
1342 }
1343
1344 /*
1345  * create control core:
1346  * called from init.c
1347  */
1348 int snd_ctl_create(struct snd_card *card)
1349 {
1350         static struct snd_device_ops ops = {
1351                 .dev_free = snd_ctl_dev_free,
1352                 .dev_register = snd_ctl_dev_register,
1353                 .dev_disconnect = snd_ctl_dev_disconnect,
1354                 .dev_unregister = snd_ctl_dev_unregister
1355         };
1356
1357         snd_assert(card != NULL, return -ENXIO);
1358         return snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1359 }