sound/core/control.c

   1 /*
   2  *  Routines for driver control interface
   3  *  Copyright (c) by Jaroslav Kysela <[email protected]>
   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/threads.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/slab.h>
  25 #include <linux/vmalloc.h>
  26 #include <linux/time.h>
  27 #include <sound/core.h>
  28 #include <sound/minors.h>
  29 #include <sound/info.h>
  30 #include <sound/control.h>
  31
  32 /* max number of user-defined controls */
  33 #define MAX_USER_CONTROLS       32
  34 #define MAX_CONTROL_COUNT       1028
  35
  36 struct snd_kctl_ioctl {
  37         struct list_head list;          /* list of all ioctls */
  38         snd_kctl_ioctl_func_t fioctl;
  39 };
  40
  41 static DECLARE_RWSEM(snd_ioctl_rwsem);
  42 static LIST_HEAD(snd_control_ioctls);
  43 #ifdef CONFIG_COMPAT
  44 static LIST_HEAD(snd_control_compat_ioctls);
  45 #endif
  46
  47 static int snd_ctl_open(struct inode *inode, struct file *file)
  48 {
  49         unsigned long flags;
  50         struct snd_card *card;
  51         struct snd_ctl_file *ctl;
  52         int err;
  53
  54         err = nonseekable_open(inode, file);
  55         if (err < 0)
  56                 return err;
  57
  58         card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
  59         if (!card) {
  60                 err = -ENODEV;
  61                 goto __error1;
  62         }
  63         err = snd_card_file_add(card, file);
  64         if (err < 0) {
  65                 err = -ENODEV;
  66                 goto __error1;
  67         }
  68         if (!try_module_get(card->module)) {
  69                 err = -EFAULT;
  70                 goto __error2;
  71         }
  72         ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
  73         if (ctl == NULL) {
  74                 err = -ENOMEM;
  75                 goto __error;
  76         }
  77         INIT_LIST_HEAD(&ctl->events);
  78         init_waitqueue_head(&ctl->change_sleep);
  79         spin_lock_init(&ctl->read_lock);
  80         ctl->card = card;
  81         ctl->prefer_pcm_subdevice = -1;
  82         ctl->prefer_rawmidi_subdevice = -1;
  83         ctl->pid = get_pid(task_pid(current));
  84         file->private_data = ctl;
  85         write_lock_irqsave(&card->ctl_files_rwlock, flags);
  86         list_add_tail(&ctl->list, &card->ctl_files);
  87         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
  88         return 0;
  89
  90       __error:
  91         module_put(card->module);
  92       __error2:
  93         snd_card_file_remove(card, file);
  94       __error1:
  95         return err;
  96 }
  97
  98 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
  99 {
 100         unsigned long flags;
 101         struct snd_kctl_event *cread;
 102
 103         spin_lock_irqsave(&ctl->read_lock, flags);
 104         while (!list_empty(&ctl->events)) {
 105                 cread = snd_kctl_event(ctl->events.next);
 106                 list_del(&cread->list);
 107                 kfree(cread);
 108         }
 109         spin_unlock_irqrestore(&ctl->read_lock, flags);
 110 }
 111
 112 static int snd_ctl_release(struct inode *inode, struct file *file)
 113 {
 114         unsigned long flags;
 115         struct snd_card *card;
 116         struct snd_ctl_file *ctl;
 117         struct snd_kcontrol *control;
 118         unsigned int idx;
 119
 120         ctl = file->private_data;
 121         file->private_data = NULL;
 122         card = ctl->card;
 123         write_lock_irqsave(&card->ctl_files_rwlock, flags);
 124         list_del(&ctl->list);
 125         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 126         down_write(&card->controls_rwsem);
 127         list_for_each_entry(control, &card->controls, list)
 128                 for (idx = 0; idx < control->count; idx++)
 129                         if (control->vd[idx].owner == ctl)
 130                                 control->vd[idx].owner = NULL;
 131         up_write(&card->controls_rwsem);
 132         snd_ctl_empty_read_queue(ctl);
 133         put_pid(ctl->pid);
 134         kfree(ctl);
 135         module_put(card->module);
 136         snd_card_file_remove(card, file);
 137         return 0;
 138 }
 139
 140 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 141                     struct snd_ctl_elem_id *id)
 142 {
 143         unsigned long flags;
 144         struct snd_ctl_file *ctl;
 145         struct snd_kctl_event *ev;
 146
 147         if (snd_BUG_ON(!card || !id))
 148                 return;
 149         read_lock(&card->ctl_files_rwlock);
 150 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 151         card->mixer_oss_change_count++;
 152 #endif
 153         list_for_each_entry(ctl, &card->ctl_files, list) {
 154                 if (!ctl->subscribed)
 155                         continue;
 156                 spin_lock_irqsave(&ctl->read_lock, flags);
 157                 list_for_each_entry(ev, &ctl->events, list) {
 158                         if (ev->id.numid == id->numid) {
 159                                 ev->mask |= mask;
 160                                 goto _found;
 161                         }
 162                 }
 163                 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
 164                 if (ev) {
 165                         ev->id = *id;
 166                         ev->mask = mask;
 167                         list_add_tail(&ev->list, &ctl->events);
 168                 } else {
 169                         snd_printk(KERN_ERR "No memory available to allocate event\n");
 170                 }
 171         _found:
 172                 wake_up(&ctl->change_sleep);
 173                 spin_unlock_irqrestore(&ctl->read_lock, flags);
 174                 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
 175         }
 176         read_unlock(&card->ctl_files_rwlock);
 177 }
 178
 179 EXPORT_SYMBOL(snd_ctl_notify);
 180
 181 /**
 182  * snd_ctl_new - create a control instance from the template
 183  * @control: the control template
 184  * @access: the default control access
 185  *
 186  * Allocates a new struct snd_kcontrol instance and copies the given template
 187  * to the new instance. It does not copy volatile data (access).
 188  *
 189  * Returns the pointer of the new instance, or NULL on failure.
 190  */
 191 static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control,
 192                                         unsigned int access)
 193 {
 194         struct snd_kcontrol *kctl;
 195         unsigned int idx;
 196
 197         if (snd_BUG_ON(!control || !control->count))
 198                 return NULL;
 199
 200         if (control->count > MAX_CONTROL_COUNT)
 201                 return NULL;
 202
 203         kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL);
 204         if (kctl == NULL) {
 205                 snd_printk(KERN_ERR "Cannot allocate control instance\n");
 206                 return NULL;
 207         }
 208         *kctl = *control;
 209         for (idx = 0; idx < kctl->count; idx++)
 210                 kctl->vd[idx].access = access;
 211         return kctl;
 212 }
 213
 214 /**
 215  * snd_ctl_new1 - create a control instance from the template
 216  * @ncontrol: the initialization record
 217  * @private_data: the private data to set
 218  *
 219  * Allocates a new struct snd_kcontrol instance and initialize from the given
 220  * template.  When the access field of ncontrol is 0, it's assumed as
 221  * READWRITE access. When the count field is 0, it's assumes as one.
 222  *
 223  * Returns the pointer of the newly generated instance, or NULL on failure.
 224  */
 225 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
 226                                   void *private_data)
 227 {
 228         struct snd_kcontrol kctl;
 229         unsigned int access;
 230
 231         if (snd_BUG_ON(!ncontrol || !ncontrol->info))
 232                 return NULL;
 233         memset(&kctl, 0, sizeof(kctl));
 234         kctl.id.iface = ncontrol->iface;
 235         kctl.id.device = ncontrol->device;
 236         kctl.id.subdevice = ncontrol->subdevice;
 237         if (ncontrol->name) {
 238                 strlcpy(kctl.id.name, ncontrol->name, sizeof(kctl.id.name));
 239                 if (strcmp(ncontrol->name, kctl.id.name) != 0)
 240                         snd_printk(KERN_WARNING
 241                                    "Control name '%s' truncated to '%s'\n",
 242                                    ncontrol->name, kctl.id.name);
 243         }
 244         kctl.id.index = ncontrol->index;
 245         kctl.count = ncontrol->count ? ncontrol->count : 1;
 246         access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
 247                  (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
 248                                       SNDRV_CTL_ELEM_ACCESS_INACTIVE|
 249                                       SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE|
 250                                       SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND|
 251                                       SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK));
 252         kctl.info = ncontrol->info;
 253         kctl.get = ncontrol->get;
 254         kctl.put = ncontrol->put;
 255         kctl.tlv.p = ncontrol->tlv.p;
 256         kctl.private_value = ncontrol->private_value;
 257         kctl.private_data = private_data;
 258         return snd_ctl_new(&kctl, access);
 259 }
 260
 261 EXPORT_SYMBOL(snd_ctl_new1);
 262
 263 /**
 264  * snd_ctl_free_one - release the control instance
 265  * @kcontrol: the control instance
 266  *
 267  * Releases the control instance created via snd_ctl_new()
 268  * or snd_ctl_new1().
 269  * Don't call this after the control was added to the card.
 270  */
 271 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
 272 {
 273         if (kcontrol) {
 274                 if (kcontrol->private_free)
 275                         kcontrol->private_free(kcontrol);
 276                 kfree(kcontrol);
 277         }
 278 }
 279
 280 EXPORT_SYMBOL(snd_ctl_free_one);
 281
 282 static unsigned int snd_ctl_hole_check(struct snd_card *card,
 283                                        unsigned int count)
 284 {
 285         struct snd_kcontrol *kctl;
 286
 287         list_for_each_entry(kctl, &card->controls, list) {
 288                 if ((kctl->id.numid <= card->last_numid &&
 289                      kctl->id.numid + kctl->count > card->last_numid) ||
 290                     (kctl->id.numid <= card->last_numid + count - 1 &&
 291                      kctl->id.numid + kctl->count > card->last_numid + count - 1))
 292                         return card->last_numid = kctl->id.numid + kctl->count - 1;
 293         }
 294         return card->last_numid;
 295 }
 296
 297 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 298 {
 299         unsigned int last_numid, iter = 100000;
 300
 301         last_numid = card->last_numid;
 302         while (last_numid != snd_ctl_hole_check(card, count)) {
 303                 if (--iter == 0) {
 304                         /* this situation is very unlikely */
 305                         snd_printk(KERN_ERR "unable to allocate new control numid\n");
 306                         return -ENOMEM;
 307                 }
 308                 last_numid = card->last_numid;
 309         }
 310         return 0;
 311 }
 312
 313 /**
 314  * snd_ctl_add - add the control instance to the card
 315  * @card: the card instance
 316  * @kcontrol: the control instance to add
 317  *
 318  * Adds the control instance created via snd_ctl_new() or
 319  * snd_ctl_new1() to the given card. Assigns also an unique
 320  * numid used for fast search.
 321  *
 322  * Returns zero if successful, or a negative error code on failure.
 323  *
 324  * It frees automatically the control which cannot be added.
 325  */
 326 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 327 {
 328         struct snd_ctl_elem_id id;
 329         unsigned int idx;
 330         int err = -EINVAL;
 331
 332         if (! kcontrol)
 333                 return err;
 334         if (snd_BUG_ON(!card || !kcontrol->info))
 335                 goto error;
 336         id = kcontrol->id;
 337         down_write(&card->controls_rwsem);
 338         if (snd_ctl_find_id(card, &id)) {
 339                 up_write(&card->controls_rwsem);
 340                 snd_printd(KERN_ERR "control %i:%i:%i:%s:%i is already present\n",
 341                                         id.iface,
 342                                         id.device,
 343                                         id.subdevice,
 344                                         id.name,
 345                                         id.index);
 346                 err = -EBUSY;
 347                 goto error;
 348         }
 349         if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 350                 up_write(&card->controls_rwsem);
 351                 err = -ENOMEM;
 352                 goto error;
 353         }
 354         list_add_tail(&kcontrol->list, &card->controls);
 355         card->controls_count += kcontrol->count;
 356         kcontrol->id.numid = card->last_numid + 1;
 357         card->last_numid += kcontrol->count;
 358         up_write(&card->controls_rwsem);
 359         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 360                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 361         return 0;
 362
 363  error:
 364         snd_ctl_free_one(kcontrol);
 365         return err;
 366 }
 367
 368 EXPORT_SYMBOL(snd_ctl_add);
 369
 370 /**
 371  * snd_ctl_remove - remove the control from the card and release it
 372  * @card: the card instance
 373  * @kcontrol: the control instance to remove
 374  *
 375  * Removes the control from the card and then releases the instance.
 376  * You don't need to call snd_ctl_free_one(). You must be in
 377  * the write lock - down_write(&card->controls_rwsem).
 378  *
 379  * Returns 0 if successful, or a negative error code on failure.
 380  */
 381 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 382 {
 383         struct snd_ctl_elem_id id;
 384         unsigned int idx;
 385
 386         if (snd_BUG_ON(!card || !kcontrol))
 387                 return -EINVAL;
 388         list_del(&kcontrol->list);
 389         card->controls_count -= kcontrol->count;
 390         id = kcontrol->id;
 391         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 392                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
 393         snd_ctl_free_one(kcontrol);
 394         return 0;
 395 }
 396
 397 EXPORT_SYMBOL(snd_ctl_remove);
 398
 399 /**
 400  * snd_ctl_remove_id - remove the control of the given id and release it
 401  * @card: the card instance
 402  * @id: the control id to remove
 403  *
 404  * Finds the control instance with the given id, removes it from the
 405  * card list and releases it.
 406  *
 407  * Returns 0 if successful, or a negative error code on failure.
 408  */
 409 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 410 {
 411         struct snd_kcontrol *kctl;
 412         int ret;
 413
 414         down_write(&card->controls_rwsem);
 415         kctl = snd_ctl_find_id(card, id);
 416         if (kctl == NULL) {
 417                 up_write(&card->controls_rwsem);
 418                 return -ENOENT;
 419         }
 420         ret = snd_ctl_remove(card, kctl);
 421         up_write(&card->controls_rwsem);
 422         return ret;
 423 }
 424
 425 EXPORT_SYMBOL(snd_ctl_remove_id);
 426
 427 /**
 428  * snd_ctl_remove_user_ctl - remove and release the unlocked user control
 429  * @file: active control handle
 430  * @id: the control id to remove
 431  *
 432  * Finds the control instance with the given id, removes it from the
 433  * card list and releases it.
 434  *
 435  * Returns 0 if successful, or a negative error code on failure.
 436  */
 437 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
 438                                    struct snd_ctl_elem_id *id)
 439 {
 440         struct snd_card *card = file->card;
 441         struct snd_kcontrol *kctl;
 442         int idx, ret;
 443
 444         down_write(&card->controls_rwsem);
 445         kctl = snd_ctl_find_id(card, id);
 446         if (kctl == NULL) {
 447                 ret = -ENOENT;
 448                 goto error;
 449         }
 450         if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
 451                 ret = -EINVAL;
 452                 goto error;
 453         }
 454         for (idx = 0; idx < kctl->count; idx++)
 455                 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
 456                         ret = -EBUSY;
 457                         goto error;
 458                 }
 459         ret = snd_ctl_remove(card, kctl);
 460         if (ret < 0)
 461                 goto error;
 462         card->user_ctl_count--;
 463 error:
 464         up_write(&card->controls_rwsem);
 465         return ret;
 466 }
 467
 468 /**
 469  * snd_ctl_rename_id - replace the id of a control on the card
 470  * @card: the card instance
 471  * @src_id: the old id
 472  * @dst_id: the new id
 473  *
 474  * Finds the control with the old id from the card, and replaces the
 475  * id with the new one.
 476  *
 477  * Returns zero if successful, or a negative error code on failure.
 478  */
 479 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 480                       struct snd_ctl_elem_id *dst_id)
 481 {
 482         struct snd_kcontrol *kctl;
 483
 484         down_write(&card->controls_rwsem);
 485         kctl = snd_ctl_find_id(card, src_id);
 486         if (kctl == NULL) {
 487                 up_write(&card->controls_rwsem);
 488                 return -ENOENT;
 489         }
 490         kctl->id = *dst_id;
 491         kctl->id.numid = card->last_numid + 1;
 492         card->last_numid += kctl->count;
 493         up_write(&card->controls_rwsem);
 494         return 0;
 495 }
 496
 497 EXPORT_SYMBOL(snd_ctl_rename_id);
 498
 499 /**
 500  * snd_ctl_find_numid - find the control instance with the given number-id
 501  * @card: the card instance
 502  * @numid: the number-id to search
 503  *
 504  * Finds the control instance with the given number-id from the card.
 505  *
 506  * Returns the pointer of the instance if found, or NULL if not.
 507  *
 508  * The caller must down card->controls_rwsem before calling this function
 509  * (if the race condition can happen).
 510  */
 511 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 512 {
 513         struct snd_kcontrol *kctl;
 514
 515         if (snd_BUG_ON(!card || !numid))
 516                 return NULL;
 517         list_for_each_entry(kctl, &card->controls, list) {
 518                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 519                         return kctl;
 520         }
 521         return NULL;
 522 }
 523
 524 EXPORT_SYMBOL(snd_ctl_find_numid);
 525
 526 /**
 527  * snd_ctl_find_id - find the control instance with the given id
 528  * @card: the card instance
 529  * @id: the id to search
 530  *
 531  * Finds the control instance with the given id from the card.
 532  *
 533  * Returns the pointer of the instance if found, or NULL if not.
 534  *
 535  * The caller must down card->controls_rwsem before calling this function
 536  * (if the race condition can happen).
 537  */
 538 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 539                                      struct snd_ctl_elem_id *id)
 540 {
 541         struct snd_kcontrol *kctl;
 542
 543         if (snd_BUG_ON(!card || !id))
 544                 return NULL;
 545         if (id->numid != 0)
 546                 return snd_ctl_find_numid(card, id->numid);
 547         list_for_each_entry(kctl, &card->controls, list) {
 548                 if (kctl->id.iface != id->iface)
 549                         continue;
 550                 if (kctl->id.device != id->device)
 551                         continue;
 552                 if (kctl->id.subdevice != id->subdevice)
 553                         continue;
 554                 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
 555                         continue;
 556                 if (kctl->id.index > id->index)
 557                         continue;
 558                 if (kctl->id.index + kctl->count <= id->index)
 559                         continue;
 560                 return kctl;
 561         }
 562         return NULL;
 563 }
 564
 565 EXPORT_SYMBOL(snd_ctl_find_id);
 566
 567 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 568                              unsigned int cmd, void __user *arg)
 569 {
 570         struct snd_ctl_card_info *info;
 571
 572         info = kzalloc(sizeof(*info), GFP_KERNEL);
 573         if (! info)
 574                 return -ENOMEM;
 575         down_read(&snd_ioctl_rwsem);
 576         info->card = card->number;
 577         strlcpy(info->id, card->id, sizeof(info->id));
 578         strlcpy(info->driver, card->driver, sizeof(info->driver));
 579         strlcpy(info->name, card->shortname, sizeof(info->name));
 580         strlcpy(info->longname, card->longname, sizeof(info->longname));
 581         strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
 582         strlcpy(info->components, card->components, sizeof(info->components));
 583         up_read(&snd_ioctl_rwsem);
 584         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 585                 kfree(info);
 586                 return -EFAULT;
 587         }
 588         kfree(info);
 589         return 0;
 590 }
 591
 592 static int snd_ctl_elem_list(struct snd_card *card,
 593                              struct snd_ctl_elem_list __user *_list)
 594 {
 595         struct list_head *plist;
 596         struct snd_ctl_elem_list list;
 597         struct snd_kcontrol *kctl;
 598         struct snd_ctl_elem_id *dst, *id;
 599         unsigned int offset, space, first, jidx;
 600
 601         if (copy_from_user(&list, _list, sizeof(list)))
 602                 return -EFAULT;
 603         offset = list.offset;
 604         space = list.space;
 605         first = 0;
 606         /* try limit maximum space */
 607         if (space > 16384)
 608                 return -ENOMEM;
 609         if (space > 0) {
 610                 /* allocate temporary buffer for atomic operation */
 611                 dst = vmalloc(space * sizeof(struct snd_ctl_elem_id));
 612                 if (dst == NULL)
 613                         return -ENOMEM;
 614                 down_read(&card->controls_rwsem);
 615                 list.count = card->controls_count;
 616                 plist = card->controls.next;
 617                 while (plist != &card->controls) {
 618                         if (offset == 0)
 619                                 break;
 620                         kctl = snd_kcontrol(plist);
 621                         if (offset < kctl->count)
 622                                 break;
 623                         offset -= kctl->count;
 624                         plist = plist->next;
 625                 }
 626                 list.used = 0;
 627                 id = dst;
 628                 while (space > 0 && plist != &card->controls) {
 629                         kctl = snd_kcontrol(plist);
 630                         for (jidx = offset; space > 0 && jidx < kctl->count; jidx++) {
 631                                 snd_ctl_build_ioff(id, kctl, jidx);
 632                                 id++;
 633                                 space--;
 634                                 list.used++;
 635                         }
 636                         plist = plist->next;
 637                         offset = 0;
 638                 }
 639                 up_read(&card->controls_rwsem);
 640                 if (list.used > 0 &&
 641                     copy_to_user(list.pids, dst,
 642                                  list.used * sizeof(struct snd_ctl_elem_id))) {
 643                         vfree(dst);
 644                         return -EFAULT;
 645                 }
 646                 vfree(dst);
 647         } else {
 648                 down_read(&card->controls_rwsem);
 649                 list.count = card->controls_count;
 650                 up_read(&card->controls_rwsem);
 651         }
 652         if (copy_to_user(_list, &list, sizeof(list)))
 653                 return -EFAULT;
 654         return 0;
 655 }
 656
 657 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 658                              struct snd_ctl_elem_info *info)
 659 {
 660         struct snd_card *card = ctl->card;
 661         struct snd_kcontrol *kctl;
 662         struct snd_kcontrol_volatile *vd;
 663         unsigned int index_offset;
 664         int result;
 665
 666         down_read(&card->controls_rwsem);
 667         kctl = snd_ctl_find_id(card, &info->id);
 668         if (kctl == NULL) {
 669                 up_read(&card->controls_rwsem);
 670                 return -ENOENT;
 671         }
 672 #ifdef CONFIG_SND_DEBUG
 673         info->access = 0;
 674 #endif
 675         result = kctl->info(kctl, info);
 676         if (result >= 0) {
 677                 snd_BUG_ON(info->access);
 678                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
 679                 vd = &kctl->vd[index_offset];
 680                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
 681                 info->access = vd->access;
 682                 if (vd->owner) {
 683                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
 684                         if (vd->owner == ctl)
 685                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
 686                         info->owner = pid_vnr(vd->owner->pid);
 687                 } else {
 688                         info->owner = -1;
 689                 }
 690         }
 691         up_read(&card->controls_rwsem);
 692         return result;
 693 }
 694
 695 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
 696                                   struct snd_ctl_elem_info __user *_info)
 697 {
 698         struct snd_ctl_elem_info info;
 699         int result;
 700
 701         if (copy_from_user(&info, _info, sizeof(info)))
 702                 return -EFAULT;
 703         snd_power_lock(ctl->card);
 704         result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
 705         if (result >= 0)
 706                 result = snd_ctl_elem_info(ctl, &info);
 707         snd_power_unlock(ctl->card);
 708         if (result >= 0)
 709                 if (copy_to_user(_info, &info, sizeof(info)))
 710                         return -EFAULT;
 711         return result;
 712 }
 713
 714 static int snd_ctl_elem_read(struct snd_card *card,
 715                              struct snd_ctl_elem_value *control)
 716 {
 717         struct snd_kcontrol *kctl;
 718         struct snd_kcontrol_volatile *vd;
 719         unsigned int index_offset;
 720         int result;
 721
 722         down_read(&card->controls_rwsem);
 723         kctl = snd_ctl_find_id(card, &control->id);
 724         if (kctl == NULL) {
 725                 result = -ENOENT;
 726         } else {
 727                 index_offset = snd_ctl_get_ioff(kctl, &control->id);
 728                 vd = &kctl->vd[index_offset];
 729                 if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) &&
 730                     kctl->get != NULL) {
 731                         snd_ctl_build_ioff(&control->id, kctl, index_offset);
 732                         result = kctl->get(kctl, control);
 733                 } else
 734                         result = -EPERM;
 735         }
 736         up_read(&card->controls_rwsem);
 737         return result;
 738 }
 739
 740 static int snd_ctl_elem_read_user(struct snd_card *card,
 741                                   struct snd_ctl_elem_value __user *_control)
 742 {
 743         struct snd_ctl_elem_value *control;
 744         int result;
 745
 746         control = memdup_user(_control, sizeof(*control));
 747         if (IS_ERR(control))
 748                 return PTR_ERR(control);
 749
 750         snd_power_lock(card);
 751         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 752         if (result >= 0)
 753                 result = snd_ctl_elem_read(card, control);
 754         snd_power_unlock(card);
 755         if (result >= 0)
 756                 if (copy_to_user(_control, control, sizeof(*control)))
 757                         result = -EFAULT;
 758         kfree(control);
 759         return result;
 760 }
 761
 762 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
 763                               struct snd_ctl_elem_value *control)
 764 {
 765         struct snd_kcontrol *kctl;
 766         struct snd_kcontrol_volatile *vd;
 767         unsigned int index_offset;
 768         int result;
 769
 770         down_read(&card->controls_rwsem);
 771         kctl = snd_ctl_find_id(card, &control->id);
 772         if (kctl == NULL) {
 773                 result = -ENOENT;
 774         } else {
 775                 index_offset = snd_ctl_get_ioff(kctl, &control->id);
 776                 vd = &kctl->vd[index_offset];
 777                 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
 778                     kctl->put == NULL ||
 779                     (file && vd->owner && vd->owner != file)) {
 780                         result = -EPERM;
 781                 } else {
 782                         snd_ctl_build_ioff(&control->id, kctl, index_offset);
 783                         result = kctl->put(kctl, control);
 784                 }
 785                 if (result > 0) {
 786                         up_read(&card->controls_rwsem);
 787                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 788                                        &control->id);
 789                         return 0;
 790                 }
 791         }
 792         up_read(&card->controls_rwsem);
 793         return result;
 794 }
 795
 796 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
 797                                    struct snd_ctl_elem_value __user *_control)
 798 {
 799         struct snd_ctl_elem_value *control;
 800         struct snd_card *card;
 801         int result;
 802
 803         control = memdup_user(_control, sizeof(*control));
 804         if (IS_ERR(control))
 805                 return PTR_ERR(control);
 806
 807         card = file->card;
 808         snd_power_lock(card);
 809         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 810         if (result >= 0)
 811                 result = snd_ctl_elem_write(card, file, control);
 812         snd_power_unlock(card);
 813         if (result >= 0)
 814                 if (copy_to_user(_control, control, sizeof(*control)))
 815                         result = -EFAULT;
 816         kfree(control);
 817         return result;
 818 }
 819
 820 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
 821                              struct snd_ctl_elem_id __user *_id)
 822 {
 823         struct snd_card *card = file->card;
 824         struct snd_ctl_elem_id id;
 825         struct snd_kcontrol *kctl;
 826         struct snd_kcontrol_volatile *vd;
 827         int result;
 828
 829         if (copy_from_user(&id, _id, sizeof(id)))
 830                 return -EFAULT;
 831         down_write(&card->controls_rwsem);
 832         kctl = snd_ctl_find_id(card, &id);
 833         if (kctl == NULL) {
 834                 result = -ENOENT;
 835         } else {
 836                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
 837                 if (vd->owner != NULL)
 838                         result = -EBUSY;
 839                 else {
 840                         vd->owner = file;
 841                         result = 0;
 842                 }
 843         }
 844         up_write(&card->controls_rwsem);
 845         return result;
 846 }
 847
 848 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
 849                                struct snd_ctl_elem_id __user *_id)
 850 {
 851         struct snd_card *card = file->card;
 852         struct snd_ctl_elem_id id;
 853         struct snd_kcontrol *kctl;
 854         struct snd_kcontrol_volatile *vd;
 855         int result;
 856
 857         if (copy_from_user(&id, _id, sizeof(id)))
 858                 return -EFAULT;
 859         down_write(&card->controls_rwsem);
 860         kctl = snd_ctl_find_id(card, &id);
 861         if (kctl == NULL) {
 862                 result = -ENOENT;
 863         } else {
 864                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
 865                 if (vd->owner == NULL)
 866                         result = -EINVAL;
 867                 else if (vd->owner != file)
 868                         result = -EPERM;
 869                 else {
 870                         vd->owner = NULL;
 871                         result = 0;
 872                 }
 873         }
 874         up_write(&card->controls_rwsem);
 875         return result;
 876 }
 877
 878 struct user_element {
 879         struct snd_ctl_elem_info info;
 880         void *elem_data;                /* element data */
 881         unsigned long elem_data_size;   /* size of element data in bytes */
 882         void *tlv_data;                 /* TLV data */
 883         unsigned long tlv_data_size;    /* TLV data size */
 884         void *priv_data;                /* private data (like strings for enumerated type) */
 885         unsigned long priv_data_size;   /* size of private data in bytes */
 886 };
 887
 888 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
 889                                   struct snd_ctl_elem_info *uinfo)
 890 {
 891         struct user_element *ue = kcontrol->private_data;
 892
 893         *uinfo = ue->info;
 894         return 0;
 895 }
 896
 897 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
 898                                  struct snd_ctl_elem_value *ucontrol)
 899 {
 900         struct user_element *ue = kcontrol->private_data;
 901
 902         memcpy(&ucontrol->value, ue->elem_data, ue->elem_data_size);
 903         return 0;
 904 }
 905
 906 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
 907                                  struct snd_ctl_elem_value *ucontrol)
 908 {
 909         int change;
 910         struct user_element *ue = kcontrol->private_data;
 911
 912         change = memcmp(&ucontrol->value, ue->elem_data, ue->elem_data_size) != 0;
 913         if (change)
 914                 memcpy(ue->elem_data, &ucontrol->value, ue->elem_data_size);
 915         return change;
 916 }
 917
 918 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol,
 919                                  int op_flag,
 920                                  unsigned int size,
 921                                  unsigned int __user *tlv)
 922 {
 923         struct user_element *ue = kcontrol->private_data;
 924         int change = 0;
 925         void *new_data;
 926
 927         if (op_flag > 0) {
 928                 if (size > 1024 * 128)  /* sane value */
 929                         return -EINVAL;
 930
 931                 new_data = memdup_user(tlv, size);
 932                 if (IS_ERR(new_data))
 933                         return PTR_ERR(new_data);
 934                 change = ue->tlv_data_size != size;
 935                 if (!change)
 936                         change = memcmp(ue->tlv_data, new_data, size);
 937                 kfree(ue->tlv_data);
 938                 ue->tlv_data = new_data;
 939                 ue->tlv_data_size = size;
 940         } else {
 941                 if (! ue->tlv_data_size || ! ue->tlv_data)
 942                         return -ENXIO;
 943                 if (size < ue->tlv_data_size)
 944                         return -ENOSPC;
 945                 if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size))
 946                         return -EFAULT;
 947         }
 948         return change;
 949 }
 950
 951 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
 952 {
 953         struct user_element *ue = kcontrol->private_data;
 954         if (ue->tlv_data)
 955                 kfree(ue->tlv_data);
 956         kfree(ue);
 957 }
 958
 959 static int snd_ctl_elem_add(struct snd_ctl_file *file,
 960                             struct snd_ctl_elem_info *info, int replace)
 961 {
 962         struct snd_card *card = file->card;
 963         struct snd_kcontrol kctl, *_kctl;
 964         unsigned int access;
 965         long private_size;
 966         struct user_element *ue;
 967         int idx, err;
 968
 969         if (card->user_ctl_count >= MAX_USER_CONTROLS)
 970                 return -ENOMEM;
 971         if (info->count < 1)
 972                 return -EINVAL;
 973         access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
 974                 (info->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
 975                                  SNDRV_CTL_ELEM_ACCESS_INACTIVE|
 976                                  SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE));
 977         info->id.numid = 0;
 978         memset(&kctl, 0, sizeof(kctl));
 979         down_write(&card->controls_rwsem);
 980         _kctl = snd_ctl_find_id(card, &info->id);
 981         err = 0;
 982         if (_kctl) {
 983                 if (replace)
 984                         err = snd_ctl_remove(card, _kctl);
 985                 else
 986                         err = -EBUSY;
 987         } else {
 988                 if (replace)
 989                         err = -ENOENT;
 990         }
 991         up_write(&card->controls_rwsem);
 992         if (err < 0)
 993                 return err;
 994         memcpy(&kctl.id, &info->id, sizeof(info->id));
 995         kctl.count = info->owner ? info->owner : 1;
 996         access |= SNDRV_CTL_ELEM_ACCESS_USER;
 997         kctl.info = snd_ctl_elem_user_info;
 998         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
 999                 kctl.get = snd_ctl_elem_user_get;
1000         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1001                 kctl.put = snd_ctl_elem_user_put;
1002         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE) {
1003                 kctl.tlv.c = snd_ctl_elem_user_tlv;
1004                 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1005         }
1006         switch (info->type) {
1007         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
1008         case SNDRV_CTL_ELEM_TYPE_INTEGER:
1009                 private_size = sizeof(long);
1010                 if (info->count > 128)
1011                         return -EINVAL;
1012                 break;
1013         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1014                 private_size = sizeof(long long);
1015                 if (info->count > 64)
1016                         return -EINVAL;
1017                 break;
1018         case SNDRV_CTL_ELEM_TYPE_BYTES:
1019                 private_size = sizeof(unsigned char);
1020                 if (info->count > 512)
1021                         return -EINVAL;
1022                 break;
1023         case SNDRV_CTL_ELEM_TYPE_IEC958:
1024                 private_size = sizeof(struct snd_aes_iec958);
1025                 if (info->count != 1)
1026                         return -EINVAL;
1027                 break;
1028         default:
1029                 return -EINVAL;
1030         }
1031         private_size *= info->count;
1032         ue = kzalloc(sizeof(struct user_element) + private_size, GFP_KERNEL);
1033         if (ue == NULL)
1034                 return -ENOMEM;
1035         ue->info = *info;
1036         ue->info.access = 0;
1037         ue->elem_data = (char *)ue + sizeof(*ue);
1038         ue->elem_data_size = private_size;
1039         kctl.private_free = snd_ctl_elem_user_free;
1040         _kctl = snd_ctl_new(&kctl, access);
1041         if (_kctl == NULL) {
1042                 kfree(ue);
1043                 return -ENOMEM;
1044         }
1045         _kctl->private_data = ue;
1046         for (idx = 0; idx < _kctl->count; idx++)
1047                 _kctl->vd[idx].owner = file;
1048         err = snd_ctl_add(card, _kctl);
1049         if (err < 0)
1050                 return err;
1051
1052         down_write(&card->controls_rwsem);
1053         card->user_ctl_count++;
1054         up_write(&card->controls_rwsem);
1055
1056         return 0;
1057 }
1058
1059 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1060                                  struct snd_ctl_elem_info __user *_info, int replace)
1061 {
1062         struct snd_ctl_elem_info info;
1063         if (copy_from_user(&info, _info, sizeof(info)))
1064                 return -EFAULT;
1065         return snd_ctl_elem_add(file, &info, replace);
1066 }
1067
1068 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1069                                struct snd_ctl_elem_id __user *_id)
1070 {
1071         struct snd_ctl_elem_id id;
1072
1073         if (copy_from_user(&id, _id, sizeof(id)))
1074                 return -EFAULT;
1075         return snd_ctl_remove_user_ctl(file, &id);
1076 }
1077
1078 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1079 {
1080         int subscribe;
1081         if (get_user(subscribe, ptr))
1082                 return -EFAULT;
1083         if (subscribe < 0) {
1084                 subscribe = file->subscribed;
1085                 if (put_user(subscribe, ptr))
1086                         return -EFAULT;
1087                 return 0;
1088         }
1089         if (subscribe) {
1090                 file->subscribed = 1;
1091                 return 0;
1092         } else if (file->subscribed) {
1093                 snd_ctl_empty_read_queue(file);
1094                 file->subscribed = 0;
1095         }
1096         return 0;
1097 }
1098
1099 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1100                              struct snd_ctl_tlv __user *_tlv,
1101                              int op_flag)
1102 {
1103         struct snd_card *card = file->card;
1104         struct snd_ctl_tlv tlv;
1105         struct snd_kcontrol *kctl;
1106         struct snd_kcontrol_volatile *vd;
1107         unsigned int len;
1108         int err = 0;
1109
1110         if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
1111                 return -EFAULT;
1112         if (tlv.length < sizeof(unsigned int) * 2)
1113                 return -EINVAL;
1114         down_read(&card->controls_rwsem);
1115         kctl = snd_ctl_find_numid(card, tlv.numid);
1116         if (kctl == NULL) {
1117                 err = -ENOENT;
1118                 goto __kctl_end;
1119         }
1120         if (kctl->tlv.p == NULL) {
1121                 err = -ENXIO;
1122                 goto __kctl_end;
1123         }
1124         vd = &kctl->vd[tlv.numid - kctl->id.numid];
1125         if ((op_flag == 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||
1126             (op_flag > 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||
1127             (op_flag < 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0)) {
1128                 err = -ENXIO;
1129                 goto __kctl_end;
1130         }
1131         if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1132                 if (vd->owner != NULL && vd->owner != file) {
1133                         err = -EPERM;
1134                         goto __kctl_end;
1135                 }
1136                 err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv);
1137                 if (err > 0) {
1138                         up_read(&card->controls_rwsem);
1139                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &kctl->id);
1140                         return 0;
1141                 }
1142         } else {
1143                 if (op_flag) {
1144                         err = -ENXIO;
1145                         goto __kctl_end;
1146                 }
1147                 len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);
1148                 if (tlv.length < len) {
1149                         err = -ENOMEM;
1150                         goto __kctl_end;
1151                 }
1152                 if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))
1153                         err = -EFAULT;
1154         }
1155       __kctl_end:
1156         up_read(&card->controls_rwsem);
1157         return err;
1158 }
1159
1160 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1161 {
1162         struct snd_ctl_file *ctl;
1163         struct snd_card *card;
1164         struct snd_kctl_ioctl *p;
1165         void __user *argp = (void __user *)arg;
1166         int __user *ip = argp;
1167         int err;
1168
1169         ctl = file->private_data;
1170         card = ctl->card;
1171         if (snd_BUG_ON(!card))
1172                 return -ENXIO;
1173         switch (cmd) {
1174         case SNDRV_CTL_IOCTL_PVERSION:
1175                 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1176         case SNDRV_CTL_IOCTL_CARD_INFO:
1177                 return snd_ctl_card_info(card, ctl, cmd, argp);
1178         case SNDRV_CTL_IOCTL_ELEM_LIST:
1179                 return snd_ctl_elem_list(card, argp);
1180         case SNDRV_CTL_IOCTL_ELEM_INFO:
1181                 return snd_ctl_elem_info_user(ctl, argp);
1182         case SNDRV_CTL_IOCTL_ELEM_READ:
1183                 return snd_ctl_elem_read_user(card, argp);
1184         case SNDRV_CTL_IOCTL_ELEM_WRITE:
1185                 return snd_ctl_elem_write_user(ctl, argp);
1186         case SNDRV_CTL_IOCTL_ELEM_LOCK:
1187                 return snd_ctl_elem_lock(ctl, argp);
1188         case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1189                 return snd_ctl_elem_unlock(ctl, argp);
1190         case SNDRV_CTL_IOCTL_ELEM_ADD:
1191                 return snd_ctl_elem_add_user(ctl, argp, 0);
1192         case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1193                 return snd_ctl_elem_add_user(ctl, argp, 1);
1194         case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1195                 return snd_ctl_elem_remove(ctl, argp);
1196         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1197                 return snd_ctl_subscribe_events(ctl, ip);
1198         case SNDRV_CTL_IOCTL_TLV_READ:
1199                 return snd_ctl_tlv_ioctl(ctl, argp, 0);
1200         case SNDRV_CTL_IOCTL_TLV_WRITE:
1201                 return snd_ctl_tlv_ioctl(ctl, argp, 1);
1202         case SNDRV_CTL_IOCTL_TLV_COMMAND:
1203                 return snd_ctl_tlv_ioctl(ctl, argp, -1);
1204         case SNDRV_CTL_IOCTL_POWER:
1205                 return -ENOPROTOOPT;
1206         case SNDRV_CTL_IOCTL_POWER_STATE:
1207 #ifdef CONFIG_PM
1208                 return put_user(card->power_state, ip) ? -EFAULT : 0;
1209 #else
1210                 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1211 #endif
1212         }
1213         down_read(&snd_ioctl_rwsem);
1214         list_for_each_entry(p, &snd_control_ioctls, list) {
1215                 err = p->fioctl(card, ctl, cmd, arg);
1216                 if (err != -ENOIOCTLCMD) {
1217                         up_read(&snd_ioctl_rwsem);
1218                         return err;
1219                 }
1220         }
1221         up_read(&snd_ioctl_rwsem);
1222         snd_printdd("unknown ioctl = 0x%x\n", cmd);
1223         return -ENOTTY;
1224 }
1225
1226 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1227                             size_t count, loff_t * offset)
1228 {
1229         struct snd_ctl_file *ctl;
1230         int err = 0;
1231         ssize_t result = 0;
1232
1233         ctl = file->private_data;
1234         if (snd_BUG_ON(!ctl || !ctl->card))
1235                 return -ENXIO;
1236         if (!ctl->subscribed)
1237                 return -EBADFD;
1238         if (count < sizeof(struct snd_ctl_event))
1239                 return -EINVAL;
1240         spin_lock_irq(&ctl->read_lock);
1241         while (count >= sizeof(struct snd_ctl_event)) {
1242                 struct snd_ctl_event ev;
1243                 struct snd_kctl_event *kev;
1244                 while (list_empty(&ctl->events)) {
1245                         wait_queue_t wait;
1246                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1247                                 err = -EAGAIN;
1248                                 goto __end_lock;
1249                         }
1250                         init_waitqueue_entry(&wait, current);
1251                         add_wait_queue(&ctl->change_sleep, &wait);
1252                         set_current_state(TASK_INTERRUPTIBLE);
1253                         spin_unlock_irq(&ctl->read_lock);
1254                         schedule();
1255                         remove_wait_queue(&ctl->change_sleep, &wait);
1256                         if (signal_pending(current))
1257                                 return -ERESTARTSYS;
1258                         spin_lock_irq(&ctl->read_lock);
1259                 }
1260                 kev = snd_kctl_event(ctl->events.next);
1261                 ev.type = SNDRV_CTL_EVENT_ELEM;
1262                 ev.data.elem.mask = kev->mask;
1263                 ev.data.elem.id = kev->id;
1264                 list_del(&kev->list);
1265                 spin_unlock_irq(&ctl->read_lock);
1266                 kfree(kev);
1267                 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1268                         err = -EFAULT;
1269                         goto __end;
1270                 }
1271                 spin_lock_irq(&ctl->read_lock);
1272                 buffer += sizeof(struct snd_ctl_event);
1273                 count -= sizeof(struct snd_ctl_event);
1274                 result += sizeof(struct snd_ctl_event);
1275         }
1276       __end_lock:
1277         spin_unlock_irq(&ctl->read_lock);
1278       __end:
1279         return result > 0 ? result : err;
1280 }
1281
1282 static unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
1283 {
1284         unsigned int mask;
1285         struct snd_ctl_file *ctl;
1286
1287         ctl = file->private_data;
1288         if (!ctl->subscribed)
1289                 return 0;
1290         poll_wait(file, &ctl->change_sleep, wait);
1291
1292         mask = 0;
1293         if (!list_empty(&ctl->events))
1294                 mask |= POLLIN | POLLRDNORM;
1295
1296         return mask;
1297 }
1298
1299 /*
1300  * register the device-specific control-ioctls.
1301  * called from each device manager like pcm.c, hwdep.c, etc.
1302  */
1303 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1304 {
1305         struct snd_kctl_ioctl *pn;
1306
1307         pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1308         if (pn == NULL)
1309                 return -ENOMEM;
1310         pn->fioctl = fcn;
1311         down_write(&snd_ioctl_rwsem);
1312         list_add_tail(&pn->list, lists);
1313         up_write(&snd_ioctl_rwsem);
1314         return 0;
1315 }
1316
1317 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1318 {
1319         return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1320 }
1321
1322 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1323
1324 #ifdef CONFIG_COMPAT
1325 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1326 {
1327         return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1328 }
1329
1330 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1331 #endif
1332
1333 /*
1334  * de-register the device-specific control-ioctls.
1335  */
1336 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1337                                      struct list_head *lists)
1338 {
1339         struct snd_kctl_ioctl *p;
1340
1341         if (snd_BUG_ON(!fcn))
1342                 return -EINVAL;
1343         down_write(&snd_ioctl_rwsem);
1344         list_for_each_entry(p, lists, list) {
1345                 if (p->fioctl == fcn) {
1346                         list_del(&p->list);
1347                         up_write(&snd_ioctl_rwsem);
1348                         kfree(p);
1349                         return 0;
1350                 }
1351         }
1352         up_write(&snd_ioctl_rwsem);
1353         snd_BUG();
1354         return -EINVAL;
1355 }
1356
1357 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1358 {
1359         return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1360 }
1361
1362 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1363
1364 #ifdef CONFIG_COMPAT
1365 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1366 {
1367         return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1368 }
1369
1370 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1371 #endif
1372
1373 static int snd_ctl_fasync(int fd, struct file * file, int on)
1374 {
1375         struct snd_ctl_file *ctl;
1376
1377         ctl = file->private_data;
1378         return fasync_helper(fd, file, on, &ctl->fasync);
1379 }
1380
1381 /*
1382  * ioctl32 compat
1383  */
1384 #ifdef CONFIG_COMPAT
1385 #include "control_compat.c"
1386 #else
1387 #define snd_ctl_ioctl_compat    NULL
1388 #endif
1389
1390 /*
1391  *  INIT PART
1392  */
1393
1394 static const struct file_operations snd_ctl_f_ops =
1395 {
1396         .owner =        THIS_MODULE,
1397         .read =         snd_ctl_read,
1398         .open =         snd_ctl_open,
1399         .release =      snd_ctl_release,
1400         .llseek =       no_llseek,
1401         .poll =         snd_ctl_poll,
1402         .unlocked_ioctl =       snd_ctl_ioctl,
1403         .compat_ioctl = snd_ctl_ioctl_compat,
1404         .fasync =       snd_ctl_fasync,
1405 };
1406
1407 /*
1408  * registration of the control device
1409  */
1410 static int snd_ctl_dev_register(struct snd_device *device)
1411 {
1412         struct snd_card *card = device->device_data;
1413         int err, cardnum;
1414         char name[16];
1415
1416         if (snd_BUG_ON(!card))
1417                 return -ENXIO;
1418         cardnum = card->number;
1419         if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
1420                 return -ENXIO;
1421         sprintf(name, "controlC%i", cardnum);
1422         if ((err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
1423                                        &snd_ctl_f_ops, card, name)) < 0)
1424                 return err;
1425         return 0;
1426 }
1427
1428 /*
1429  * disconnection of the control device
1430  */
1431 static int snd_ctl_dev_disconnect(struct snd_device *device)
1432 {
1433         struct snd_card *card = device->device_data;
1434         struct snd_ctl_file *ctl;
1435         int err, cardnum;
1436
1437         if (snd_BUG_ON(!card))
1438                 return -ENXIO;
1439         cardnum = card->number;
1440         if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
1441                 return -ENXIO;
1442
1443         read_lock(&card->ctl_files_rwlock);
1444         list_for_each_entry(ctl, &card->ctl_files, list) {
1445                 wake_up(&ctl->change_sleep);
1446                 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1447         }
1448         read_unlock(&card->ctl_files_rwlock);
1449
1450         if ((err = snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL,
1451                                          card, -1)) < 0)
1452                 return err;
1453         return 0;
1454 }
1455
1456 /*
1457  * free all controls
1458  */
1459 static int snd_ctl_dev_free(struct snd_device *device)
1460 {
1461         struct snd_card *card = device->device_data;
1462         struct snd_kcontrol *control;
1463
1464         down_write(&card->controls_rwsem);
1465         while (!list_empty(&card->controls)) {
1466                 control = snd_kcontrol(card->controls.next);
1467                 snd_ctl_remove(card, control);
1468         }
1469         up_write(&card->controls_rwsem);
1470         return 0;
1471 }
1472
1473 /*
1474  * create control core:
1475  * called from init.c
1476  */
1477 int snd_ctl_create(struct snd_card *card)
1478 {
1479         static struct snd_device_ops ops = {
1480                 .dev_free = snd_ctl_dev_free,
1481                 .dev_register = snd_ctl_dev_register,
1482                 .dev_disconnect = snd_ctl_dev_disconnect,
1483         };
1484
1485         if (snd_BUG_ON(!card))
1486                 return -ENXIO;
1487         return snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1488 }
1489
1490 /*
1491  * Frequently used control callbacks/helpers
1492  */
1493 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
1494                               struct snd_ctl_elem_info *uinfo)
1495 {
1496         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1497         uinfo->count = 1;
1498         uinfo->value.integer.min = 0;
1499         uinfo->value.integer.max = 1;
1500         return 0;
1501 }
1502
1503 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
1504
1505 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
1506                                 struct snd_ctl_elem_info *uinfo)
1507 {
1508         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1509         uinfo->count = 2;
1510         uinfo->value.integer.min = 0;
1511         uinfo->value.integer.max = 1;
1512         return 0;
1513 }
1514
1515 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
1516
1517 /**
1518  * snd_ctl_enum_info - fills the info structure for an enumerated control
1519  * @info: the structure to be filled
1520  * @channels: the number of the control's channels; often one
1521  * @items: the number of control values; also the size of @names
1522  * @names: an array containing the names of all control values
1523  *
1524  * Sets all required fields in @info to their appropriate values.
1525  * If the control's accessibility is not the default (readable and writable),
1526  * the caller has to fill @info->access.
1527  */
1528 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
1529                       unsigned int items, const char *const names[])
1530 {
1531         info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
1532         info->count = channels;
1533         info->value.enumerated.items = items;
1534         if (info->value.enumerated.item >= items)
1535                 info->value.enumerated.item = items - 1;
1536         strlcpy(info->value.enumerated.name,
1537                 names[info->value.enumerated.item],
1538                 sizeof(info->value.enumerated.name));
1539         return 0;
1540 }
1541 EXPORT_SYMBOL(snd_ctl_enum_info);