sound/core/control.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Routines for driver control interface
   4  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   5  */
   6
   7 #include <linux/threads.h>
   8 #include <linux/interrupt.h>
   9 #include <linux/module.h>
  10 #include <linux/slab.h>
  11 #include <linux/vmalloc.h>
  12 #include <linux/time.h>
  13 #include <linux/mm.h>
  14 #include <linux/math64.h>
  15 #include <linux/sched/signal.h>
  16 #include <sound/core.h>
  17 #include <sound/minors.h>
  18 #include <sound/info.h>
  19 #include <sound/control.h>
  20
  21 /* max number of user-defined controls */
  22 #define MAX_USER_CONTROLS       32
  23 #define MAX_CONTROL_COUNT       1028
  24
  25 struct snd_kctl_ioctl {
  26         struct list_head list;          /* list of all ioctls */
  27         snd_kctl_ioctl_func_t fioctl;
  28 };
  29
  30 static DECLARE_RWSEM(snd_ioctl_rwsem);
  31 static LIST_HEAD(snd_control_ioctls);
  32 #ifdef CONFIG_COMPAT
  33 static LIST_HEAD(snd_control_compat_ioctls);
  34 #endif
  35
  36 static int snd_ctl_open(struct inode *inode, struct file *file)
  37 {
  38         unsigned long flags;
  39         struct snd_card *card;
  40         struct snd_ctl_file *ctl;
  41         int i, err;
  42
  43         err = stream_open(inode, file);
  44         if (err < 0)
  45                 return err;
  46
  47         card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
  48         if (!card) {
  49                 err = -ENODEV;
  50                 goto __error1;
  51         }
  52         err = snd_card_file_add(card, file);
  53         if (err < 0) {
  54                 err = -ENODEV;
  55                 goto __error1;
  56         }
  57         if (!try_module_get(card->module)) {
  58                 err = -EFAULT;
  59                 goto __error2;
  60         }
  61         ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
  62         if (ctl == NULL) {
  63                 err = -ENOMEM;
  64                 goto __error;
  65         }
  66         INIT_LIST_HEAD(&ctl->events);
  67         init_waitqueue_head(&ctl->change_sleep);
  68         spin_lock_init(&ctl->read_lock);
  69         ctl->card = card;
  70         for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
  71                 ctl->preferred_subdevice[i] = -1;
  72         ctl->pid = get_pid(task_pid(current));
  73         file->private_data = ctl;
  74         write_lock_irqsave(&card->ctl_files_rwlock, flags);
  75         list_add_tail(&ctl->list, &card->ctl_files);
  76         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
  77         snd_card_unref(card);
  78         return 0;
  79
  80       __error:
  81         module_put(card->module);
  82       __error2:
  83         snd_card_file_remove(card, file);
  84       __error1:
  85         if (card)
  86                 snd_card_unref(card);
  87         return err;
  88 }
  89
  90 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
  91 {
  92         unsigned long flags;
  93         struct snd_kctl_event *cread;
  94
  95         spin_lock_irqsave(&ctl->read_lock, flags);
  96         while (!list_empty(&ctl->events)) {
  97                 cread = snd_kctl_event(ctl->events.next);
  98                 list_del(&cread->list);
  99                 kfree(cread);
 100         }
 101         spin_unlock_irqrestore(&ctl->read_lock, flags);
 102 }
 103
 104 static int snd_ctl_release(struct inode *inode, struct file *file)
 105 {
 106         unsigned long flags;
 107         struct snd_card *card;
 108         struct snd_ctl_file *ctl;
 109         struct snd_kcontrol *control;
 110         unsigned int idx;
 111
 112         ctl = file->private_data;
 113         file->private_data = NULL;
 114         card = ctl->card;
 115         write_lock_irqsave(&card->ctl_files_rwlock, flags);
 116         list_del(&ctl->list);
 117         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 118         down_write(&card->controls_rwsem);
 119         list_for_each_entry(control, &card->controls, list)
 120                 for (idx = 0; idx < control->count; idx++)
 121                         if (control->vd[idx].owner == ctl)
 122                                 control->vd[idx].owner = NULL;
 123         up_write(&card->controls_rwsem);
 124         snd_ctl_empty_read_queue(ctl);
 125         put_pid(ctl->pid);
 126         kfree(ctl);
 127         module_put(card->module);
 128         snd_card_file_remove(card, file);
 129         return 0;
 130 }
 131
 132 /**
 133  * snd_ctl_notify - Send notification to user-space for a control change
 134  * @card: the card to send notification
 135  * @mask: the event mask, SNDRV_CTL_EVENT_*
 136  * @id: the ctl element id to send notification
 137  *
 138  * This function adds an event record with the given id and mask, appends
 139  * to the list and wakes up the user-space for notification.  This can be
 140  * called in the atomic context.
 141  */
 142 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 143                     struct snd_ctl_elem_id *id)
 144 {
 145         unsigned long flags;
 146         struct snd_ctl_file *ctl;
 147         struct snd_kctl_event *ev;
 148
 149         if (snd_BUG_ON(!card || !id))
 150                 return;
 151         if (card->shutdown)
 152                 return;
 153         read_lock(&card->ctl_files_rwlock);
 154 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 155         card->mixer_oss_change_count++;
 156 #endif
 157         list_for_each_entry(ctl, &card->ctl_files, list) {
 158                 if (!ctl->subscribed)
 159                         continue;
 160                 spin_lock_irqsave(&ctl->read_lock, flags);
 161                 list_for_each_entry(ev, &ctl->events, list) {
 162                         if (ev->id.numid == id->numid) {
 163                                 ev->mask |= mask;
 164                                 goto _found;
 165                         }
 166                 }
 167                 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
 168                 if (ev) {
 169                         ev->id = *id;
 170                         ev->mask = mask;
 171                         list_add_tail(&ev->list, &ctl->events);
 172                 } else {
 173                         dev_err(card->dev, "No memory available to allocate event\n");
 174                 }
 175         _found:
 176                 wake_up(&ctl->change_sleep);
 177                 spin_unlock_irqrestore(&ctl->read_lock, flags);
 178                 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
 179         }
 180         read_unlock(&card->ctl_files_rwlock);
 181 }
 182 EXPORT_SYMBOL(snd_ctl_notify);
 183
 184 /**
 185  * snd_ctl_new - create a new control instance with some elements
 186  * @kctl: the pointer to store new control instance
 187  * @count: the number of elements in this control
 188  * @access: the default access flags for elements in this control
 189  * @file: given when locking these elements
 190  *
 191  * Allocates a memory object for a new control instance. The instance has
 192  * elements as many as the given number (@count). Each element has given
 193  * access permissions (@access). Each element is locked when @file is given.
 194  *
 195  * Return: 0 on success, error code on failure
 196  */
 197 static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,
 198                        unsigned int access, struct snd_ctl_file *file)
 199 {
 200         unsigned int idx;
 201
 202         if (count == 0 || count > MAX_CONTROL_COUNT)
 203                 return -EINVAL;
 204
 205         *kctl = kzalloc(struct_size(*kctl, vd, count), GFP_KERNEL);
 206         if (!*kctl)
 207                 return -ENOMEM;
 208
 209         for (idx = 0; idx < count; idx++) {
 210                 (*kctl)->vd[idx].access = access;
 211                 (*kctl)->vd[idx].owner = file;
 212         }
 213         (*kctl)->count = count;
 214
 215         return 0;
 216 }
 217
 218 /**
 219  * snd_ctl_new1 - create a control instance from the template
 220  * @ncontrol: the initialization record
 221  * @private_data: the private data to set
 222  *
 223  * Allocates a new struct snd_kcontrol instance and initialize from the given
 224  * template.  When the access field of ncontrol is 0, it's assumed as
 225  * READWRITE access. When the count field is 0, it's assumes as one.
 226  *
 227  * Return: The pointer of the newly generated instance, or %NULL on failure.
 228  */
 229 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
 230                                   void *private_data)
 231 {
 232         struct snd_kcontrol *kctl;
 233         unsigned int count;
 234         unsigned int access;
 235         int err;
 236
 237         if (snd_BUG_ON(!ncontrol || !ncontrol->info))
 238                 return NULL;
 239
 240         count = ncontrol->count;
 241         if (count == 0)
 242                 count = 1;
 243
 244         access = ncontrol->access;
 245         if (access == 0)
 246                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
 247         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
 248                    SNDRV_CTL_ELEM_ACCESS_VOLATILE |
 249                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
 250                    SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
 251                    SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND |
 252                    SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK |
 253                    SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK);
 254
 255         err = snd_ctl_new(&kctl, count, access, NULL);
 256         if (err < 0)
 257                 return NULL;
 258
 259         /* The 'numid' member is decided when calling snd_ctl_add(). */
 260         kctl->id.iface = ncontrol->iface;
 261         kctl->id.device = ncontrol->device;
 262         kctl->id.subdevice = ncontrol->subdevice;
 263         if (ncontrol->name) {
 264                 strlcpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name));
 265                 if (strcmp(ncontrol->name, kctl->id.name) != 0)
 266                         pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
 267                                 ncontrol->name, kctl->id.name);
 268         }
 269         kctl->id.index = ncontrol->index;
 270
 271         kctl->info = ncontrol->info;
 272         kctl->get = ncontrol->get;
 273         kctl->put = ncontrol->put;
 274         kctl->tlv.p = ncontrol->tlv.p;
 275
 276         kctl->private_value = ncontrol->private_value;
 277         kctl->private_data = private_data;
 278
 279         return kctl;
 280 }
 281 EXPORT_SYMBOL(snd_ctl_new1);
 282
 283 /**
 284  * snd_ctl_free_one - release the control instance
 285  * @kcontrol: the control instance
 286  *
 287  * Releases the control instance created via snd_ctl_new()
 288  * or snd_ctl_new1().
 289  * Don't call this after the control was added to the card.
 290  */
 291 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
 292 {
 293         if (kcontrol) {
 294                 if (kcontrol->private_free)
 295                         kcontrol->private_free(kcontrol);
 296                 kfree(kcontrol);
 297         }
 298 }
 299 EXPORT_SYMBOL(snd_ctl_free_one);
 300
 301 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
 302                                           unsigned int count)
 303 {
 304         struct snd_kcontrol *kctl;
 305
 306         /* Make sure that the ids assigned to the control do not wrap around */
 307         if (card->last_numid >= UINT_MAX - count)
 308                 card->last_numid = 0;
 309
 310         list_for_each_entry(kctl, &card->controls, list) {
 311                 if (kctl->id.numid < card->last_numid + 1 + count &&
 312                     kctl->id.numid + kctl->count > card->last_numid + 1) {
 313                         card->last_numid = kctl->id.numid + kctl->count - 1;
 314                         return true;
 315                 }
 316         }
 317         return false;
 318 }
 319
 320 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 321 {
 322         unsigned int iter = 100000;
 323
 324         while (snd_ctl_remove_numid_conflict(card, count)) {
 325                 if (--iter == 0) {
 326                         /* this situation is very unlikely */
 327                         dev_err(card->dev, "unable to allocate new control numid\n");
 328                         return -ENOMEM;
 329                 }
 330         }
 331         return 0;
 332 }
 333
 334 enum snd_ctl_add_mode {
 335         CTL_ADD_EXCLUSIVE, CTL_REPLACE, CTL_ADD_ON_REPLACE,
 336 };
 337
 338 /* add/replace a new kcontrol object; call with card->controls_rwsem locked */
 339 static int __snd_ctl_add_replace(struct snd_card *card,
 340                                  struct snd_kcontrol *kcontrol,
 341                                  enum snd_ctl_add_mode mode)
 342 {
 343         struct snd_ctl_elem_id id;
 344         unsigned int idx;
 345         unsigned int count;
 346         struct snd_kcontrol *old;
 347         int err;
 348
 349         id = kcontrol->id;
 350         if (id.index > UINT_MAX - kcontrol->count)
 351                 return -EINVAL;
 352
 353         old = snd_ctl_find_id(card, &id);
 354         if (!old) {
 355                 if (mode == CTL_REPLACE)
 356                         return -EINVAL;
 357         } else {
 358                 if (mode == CTL_ADD_EXCLUSIVE) {
 359                         dev_err(card->dev,
 360                                 "control %i:%i:%i:%s:%i is already present\n",
 361                                 id.iface, id.device, id.subdevice, id.name,
 362                                 id.index);
 363                         return -EBUSY;
 364                 }
 365
 366                 err = snd_ctl_remove(card, old);
 367                 if (err < 0)
 368                         return err;
 369         }
 370
 371         if (snd_ctl_find_hole(card, kcontrol->count) < 0)
 372                 return -ENOMEM;
 373
 374         list_add_tail(&kcontrol->list, &card->controls);
 375         card->controls_count += kcontrol->count;
 376         kcontrol->id.numid = card->last_numid + 1;
 377         card->last_numid += kcontrol->count;
 378
 379         id = kcontrol->id;
 380         count = kcontrol->count;
 381         for (idx = 0; idx < count; idx++, id.index++, id.numid++)
 382                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 383
 384         return 0;
 385 }
 386
 387 static int snd_ctl_add_replace(struct snd_card *card,
 388                                struct snd_kcontrol *kcontrol,
 389                                enum snd_ctl_add_mode mode)
 390 {
 391         int err = -EINVAL;
 392
 393         if (! kcontrol)
 394                 return err;
 395         if (snd_BUG_ON(!card || !kcontrol->info))
 396                 goto error;
 397
 398         down_write(&card->controls_rwsem);
 399         err = __snd_ctl_add_replace(card, kcontrol, mode);
 400         up_write(&card->controls_rwsem);
 401         if (err < 0)
 402                 goto error;
 403         return 0;
 404
 405  error:
 406         snd_ctl_free_one(kcontrol);
 407         return err;
 408 }
 409
 410 /**
 411  * snd_ctl_add - add the control instance to the card
 412  * @card: the card instance
 413  * @kcontrol: the control instance to add
 414  *
 415  * Adds the control instance created via snd_ctl_new() or
 416  * snd_ctl_new1() to the given card. Assigns also an unique
 417  * numid used for fast search.
 418  *
 419  * It frees automatically the control which cannot be added.
 420  *
 421  * Return: Zero if successful, or a negative error code on failure.
 422  *
 423  */
 424 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 425 {
 426         return snd_ctl_add_replace(card, kcontrol, CTL_ADD_EXCLUSIVE);
 427 }
 428 EXPORT_SYMBOL(snd_ctl_add);
 429
 430 /**
 431  * snd_ctl_replace - replace the control instance of the card
 432  * @card: the card instance
 433  * @kcontrol: the control instance to replace
 434  * @add_on_replace: add the control if not already added
 435  *
 436  * Replaces the given control.  If the given control does not exist
 437  * and the add_on_replace flag is set, the control is added.  If the
 438  * control exists, it is destroyed first.
 439  *
 440  * It frees automatically the control which cannot be added or replaced.
 441  *
 442  * Return: Zero if successful, or a negative error code on failure.
 443  */
 444 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
 445                     bool add_on_replace)
 446 {
 447         return snd_ctl_add_replace(card, kcontrol,
 448                                    add_on_replace ? CTL_ADD_ON_REPLACE : CTL_REPLACE);
 449 }
 450 EXPORT_SYMBOL(snd_ctl_replace);
 451
 452 /**
 453  * snd_ctl_remove - remove the control from the card and release it
 454  * @card: the card instance
 455  * @kcontrol: the control instance to remove
 456  *
 457  * Removes the control from the card and then releases the instance.
 458  * You don't need to call snd_ctl_free_one(). You must be in
 459  * the write lock - down_write(&card->controls_rwsem).
 460  *
 461  * Return: 0 if successful, or a negative error code on failure.
 462  */
 463 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 464 {
 465         struct snd_ctl_elem_id id;
 466         unsigned int idx;
 467
 468         if (snd_BUG_ON(!card || !kcontrol))
 469                 return -EINVAL;
 470         list_del(&kcontrol->list);
 471         card->controls_count -= kcontrol->count;
 472         id = kcontrol->id;
 473         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 474                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
 475         snd_ctl_free_one(kcontrol);
 476         return 0;
 477 }
 478 EXPORT_SYMBOL(snd_ctl_remove);
 479
 480 /**
 481  * snd_ctl_remove_id - remove the control of the given id and release it
 482  * @card: the card instance
 483  * @id: the control id to remove
 484  *
 485  * Finds the control instance with the given id, removes it from the
 486  * card list and releases it.
 487  *
 488  * Return: 0 if successful, or a negative error code on failure.
 489  */
 490 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 491 {
 492         struct snd_kcontrol *kctl;
 493         int ret;
 494
 495         down_write(&card->controls_rwsem);
 496         kctl = snd_ctl_find_id(card, id);
 497         if (kctl == NULL) {
 498                 up_write(&card->controls_rwsem);
 499                 return -ENOENT;
 500         }
 501         ret = snd_ctl_remove(card, kctl);
 502         up_write(&card->controls_rwsem);
 503         return ret;
 504 }
 505 EXPORT_SYMBOL(snd_ctl_remove_id);
 506
 507 /**
 508  * snd_ctl_remove_user_ctl - remove and release the unlocked user control
 509  * @file: active control handle
 510  * @id: the control id to remove
 511  *
 512  * Finds the control instance with the given id, removes it from the
 513  * card list and releases it.
 514  *
 515  * Return: 0 if successful, or a negative error code on failure.
 516  */
 517 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
 518                                    struct snd_ctl_elem_id *id)
 519 {
 520         struct snd_card *card = file->card;
 521         struct snd_kcontrol *kctl;
 522         int idx, ret;
 523
 524         down_write(&card->controls_rwsem);
 525         kctl = snd_ctl_find_id(card, id);
 526         if (kctl == NULL) {
 527                 ret = -ENOENT;
 528                 goto error;
 529         }
 530         if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
 531                 ret = -EINVAL;
 532                 goto error;
 533         }
 534         for (idx = 0; idx < kctl->count; idx++)
 535                 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
 536                         ret = -EBUSY;
 537                         goto error;
 538                 }
 539         ret = snd_ctl_remove(card, kctl);
 540         if (ret < 0)
 541                 goto error;
 542         card->user_ctl_count--;
 543 error:
 544         up_write(&card->controls_rwsem);
 545         return ret;
 546 }
 547
 548 /**
 549  * snd_ctl_activate_id - activate/inactivate the control of the given id
 550  * @card: the card instance
 551  * @id: the control id to activate/inactivate
 552  * @active: non-zero to activate
 553  *
 554  * Finds the control instance with the given id, and activate or
 555  * inactivate the control together with notification, if changed.
 556  * The given ID data is filled with full information.
 557  *
 558  * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
 559  */
 560 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
 561                         int active)
 562 {
 563         struct snd_kcontrol *kctl;
 564         struct snd_kcontrol_volatile *vd;
 565         unsigned int index_offset;
 566         int ret;
 567
 568         down_write(&card->controls_rwsem);
 569         kctl = snd_ctl_find_id(card, id);
 570         if (kctl == NULL) {
 571                 ret = -ENOENT;
 572                 goto unlock;
 573         }
 574         index_offset = snd_ctl_get_ioff(kctl, id);
 575         vd = &kctl->vd[index_offset];
 576         ret = 0;
 577         if (active) {
 578                 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
 579                         goto unlock;
 580                 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 581         } else {
 582                 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
 583                         goto unlock;
 584                 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 585         }
 586         snd_ctl_build_ioff(id, kctl, index_offset);
 587         ret = 1;
 588  unlock:
 589         up_write(&card->controls_rwsem);
 590         if (ret > 0)
 591                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
 592         return ret;
 593 }
 594 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
 595
 596 /**
 597  * snd_ctl_rename_id - replace the id of a control on the card
 598  * @card: the card instance
 599  * @src_id: the old id
 600  * @dst_id: the new id
 601  *
 602  * Finds the control with the old id from the card, and replaces the
 603  * id with the new one.
 604  *
 605  * Return: Zero if successful, or a negative error code on failure.
 606  */
 607 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 608                       struct snd_ctl_elem_id *dst_id)
 609 {
 610         struct snd_kcontrol *kctl;
 611
 612         down_write(&card->controls_rwsem);
 613         kctl = snd_ctl_find_id(card, src_id);
 614         if (kctl == NULL) {
 615                 up_write(&card->controls_rwsem);
 616                 return -ENOENT;
 617         }
 618         kctl->id = *dst_id;
 619         kctl->id.numid = card->last_numid + 1;
 620         card->last_numid += kctl->count;
 621         up_write(&card->controls_rwsem);
 622         return 0;
 623 }
 624 EXPORT_SYMBOL(snd_ctl_rename_id);
 625
 626 /**
 627  * snd_ctl_find_numid - find the control instance with the given number-id
 628  * @card: the card instance
 629  * @numid: the number-id to search
 630  *
 631  * Finds the control instance with the given number-id from the card.
 632  *
 633  * The caller must down card->controls_rwsem before calling this function
 634  * (if the race condition can happen).
 635  *
 636  * Return: The pointer of the instance if found, or %NULL if not.
 637  *
 638  */
 639 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 640 {
 641         struct snd_kcontrol *kctl;
 642
 643         if (snd_BUG_ON(!card || !numid))
 644                 return NULL;
 645         list_for_each_entry(kctl, &card->controls, list) {
 646                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 647                         return kctl;
 648         }
 649         return NULL;
 650 }
 651 EXPORT_SYMBOL(snd_ctl_find_numid);
 652
 653 /**
 654  * snd_ctl_find_id - find the control instance with the given id
 655  * @card: the card instance
 656  * @id: the id to search
 657  *
 658  * Finds the control instance with the given id from the card.
 659  *
 660  * The caller must down card->controls_rwsem before calling this function
 661  * (if the race condition can happen).
 662  *
 663  * Return: The pointer of the instance if found, or %NULL if not.
 664  *
 665  */
 666 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 667                                      struct snd_ctl_elem_id *id)
 668 {
 669         struct snd_kcontrol *kctl;
 670
 671         if (snd_BUG_ON(!card || !id))
 672                 return NULL;
 673         if (id->numid != 0)
 674                 return snd_ctl_find_numid(card, id->numid);
 675         list_for_each_entry(kctl, &card->controls, list) {
 676                 if (kctl->id.iface != id->iface)
 677                         continue;
 678                 if (kctl->id.device != id->device)
 679                         continue;
 680                 if (kctl->id.subdevice != id->subdevice)
 681                         continue;
 682                 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
 683                         continue;
 684                 if (kctl->id.index > id->index)
 685                         continue;
 686                 if (kctl->id.index + kctl->count <= id->index)
 687                         continue;
 688                 return kctl;
 689         }
 690         return NULL;
 691 }
 692 EXPORT_SYMBOL(snd_ctl_find_id);
 693
 694 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 695                              unsigned int cmd, void __user *arg)
 696 {
 697         struct snd_ctl_card_info *info;
 698
 699         info = kzalloc(sizeof(*info), GFP_KERNEL);
 700         if (! info)
 701                 return -ENOMEM;
 702         down_read(&snd_ioctl_rwsem);
 703         info->card = card->number;
 704         strlcpy(info->id, card->id, sizeof(info->id));
 705         strlcpy(info->driver, card->driver, sizeof(info->driver));
 706         strlcpy(info->name, card->shortname, sizeof(info->name));
 707         strlcpy(info->longname, card->longname, sizeof(info->longname));
 708         strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
 709         strlcpy(info->components, card->components, sizeof(info->components));
 710         up_read(&snd_ioctl_rwsem);
 711         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 712                 kfree(info);
 713                 return -EFAULT;
 714         }
 715         kfree(info);
 716         return 0;
 717 }
 718
 719 static int snd_ctl_elem_list(struct snd_card *card,
 720                              struct snd_ctl_elem_list __user *_list)
 721 {
 722         struct snd_ctl_elem_list list;
 723         struct snd_kcontrol *kctl;
 724         struct snd_ctl_elem_id id;
 725         unsigned int offset, space, jidx;
 726         int err = 0;
 727
 728         if (copy_from_user(&list, _list, sizeof(list)))
 729                 return -EFAULT;
 730         offset = list.offset;
 731         space = list.space;
 732
 733         down_read(&card->controls_rwsem);
 734         list.count = card->controls_count;
 735         list.used = 0;
 736         if (space > 0) {
 737                 list_for_each_entry(kctl, &card->controls, list) {
 738                         if (offset >= kctl->count) {
 739                                 offset -= kctl->count;
 740                                 continue;
 741                         }
 742                         for (jidx = offset; jidx < kctl->count; jidx++) {
 743                                 snd_ctl_build_ioff(&id, kctl, jidx);
 744                                 if (copy_to_user(list.pids + list.used, &id,
 745                                                  sizeof(id))) {
 746                                         err = -EFAULT;
 747                                         goto out;
 748                                 }
 749                                 list.used++;
 750                                 if (!--space)
 751                                         goto out;
 752                         }
 753                         offset = 0;
 754                 }
 755         }
 756  out:
 757         up_read(&card->controls_rwsem);
 758         if (!err && copy_to_user(_list, &list, sizeof(list)))
 759                 err = -EFAULT;
 760         return err;
 761 }
 762
 763 /* Check whether the given kctl info is valid */
 764 static int snd_ctl_check_elem_info(struct snd_card *card,
 765                                    const struct snd_ctl_elem_info *info)
 766 {
 767         static const unsigned int max_value_counts[] = {
 768                 [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = 128,
 769                 [SNDRV_CTL_ELEM_TYPE_INTEGER]   = 128,
 770                 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
 771                 [SNDRV_CTL_ELEM_TYPE_BYTES]     = 512,
 772                 [SNDRV_CTL_ELEM_TYPE_IEC958]    = 1,
 773                 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
 774         };
 775
 776         if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
 777             info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64) {
 778                 if (card)
 779                         dev_err(card->dev,
 780                                 "control %i:%i:%i:%s:%i: invalid type %d\n",
 781                                 info->id.iface, info->id.device,
 782                                 info->id.subdevice, info->id.name,
 783                                 info->id.index, info->type);
 784                 return -EINVAL;
 785         }
 786         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
 787             info->value.enumerated.items == 0) {
 788                 if (card)
 789                         dev_err(card->dev,
 790                                 "control %i:%i:%i:%s:%i: zero enum items\n",
 791                                 info->id.iface, info->id.device,
 792                                 info->id.subdevice, info->id.name,
 793                                 info->id.index);
 794                 return -EINVAL;
 795         }
 796         if (info->count > max_value_counts[info->type]) {
 797                 if (card)
 798                         dev_err(card->dev,
 799                                 "control %i:%i:%i:%s:%i: invalid count %d\n",
 800                                 info->id.iface, info->id.device,
 801                                 info->id.subdevice, info->id.name,
 802                                 info->id.index, info->count);
 803                 return -EINVAL;
 804         }
 805
 806         return 0;
 807 }
 808
 809 /* The capacity of struct snd_ctl_elem_value.value.*/
 810 static const unsigned int value_sizes[] = {
 811         [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = sizeof(long),
 812         [SNDRV_CTL_ELEM_TYPE_INTEGER]   = sizeof(long),
 813         [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),
 814         [SNDRV_CTL_ELEM_TYPE_BYTES]     = sizeof(unsigned char),
 815         [SNDRV_CTL_ELEM_TYPE_IEC958]    = sizeof(struct snd_aes_iec958),
 816         [SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),
 817 };
 818
 819 #ifdef CONFIG_SND_CTL_VALIDATION
 820 /* fill the remaining snd_ctl_elem_value data with the given pattern */
 821 static void fill_remaining_elem_value(struct snd_ctl_elem_value *control,
 822                                       struct snd_ctl_elem_info *info,
 823                                       u32 pattern)
 824 {
 825         size_t offset = value_sizes[info->type] * info->count;
 826
 827         offset = (offset + sizeof(u32) - 1) / sizeof(u32);
 828         memset32((u32 *)control->value.bytes.data + offset, pattern,
 829                  sizeof(control->value) / sizeof(u32) - offset);
 830 }
 831
 832 /* check whether the given integer ctl value is valid */
 833 static int sanity_check_int_value(struct snd_card *card,
 834                                   const struct snd_ctl_elem_value *control,
 835                                   const struct snd_ctl_elem_info *info,
 836                                   int i)
 837 {
 838         long long lval, lmin, lmax, lstep;
 839         u64 rem;
 840
 841         switch (info->type) {
 842         default:
 843         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
 844                 lval = control->value.integer.value[i];
 845                 lmin = 0;
 846                 lmax = 1;
 847                 lstep = 0;
 848                 break;
 849         case SNDRV_CTL_ELEM_TYPE_INTEGER:
 850                 lval = control->value.integer.value[i];
 851                 lmin = info->value.integer.min;
 852                 lmax = info->value.integer.max;
 853                 lstep = info->value.integer.step;
 854                 break;
 855         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
 856                 lval = control->value.integer64.value[i];
 857                 lmin = info->value.integer64.min;
 858                 lmax = info->value.integer64.max;
 859                 lstep = info->value.integer64.step;
 860                 break;
 861         case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
 862                 lval = control->value.enumerated.item[i];
 863                 lmin = 0;
 864                 lmax = info->value.enumerated.items - 1;
 865                 lstep = 0;
 866                 break;
 867         }
 868
 869         if (lval < lmin || lval > lmax) {
 870                 dev_err(card->dev,
 871                         "control %i:%i:%i:%s:%i: value out of range %lld (%lld/%lld) at count %i\n",
 872                         control->id.iface, control->id.device,
 873                         control->id.subdevice, control->id.name,
 874                         control->id.index, lval, lmin, lmax, i);
 875                 return -EINVAL;
 876         }
 877         if (lstep) {
 878                 div64_u64_rem(lval, lstep, &rem);
 879                 if (rem) {
 880                         dev_err(card->dev,
 881                                 "control %i:%i:%i:%s:%i: unaligned value %lld (step %lld) at count %i\n",
 882                                 control->id.iface, control->id.device,
 883                                 control->id.subdevice, control->id.name,
 884                                 control->id.index, lval, lstep, i);
 885                         return -EINVAL;
 886                 }
 887         }
 888
 889         return 0;
 890 }
 891
 892 /* perform sanity checks to the given snd_ctl_elem_value object */
 893 static int sanity_check_elem_value(struct snd_card *card,
 894                                    const struct snd_ctl_elem_value *control,
 895                                    const struct snd_ctl_elem_info *info,
 896                                    u32 pattern)
 897 {
 898         size_t offset;
 899         int i, ret = 0;
 900         u32 *p;
 901
 902         switch (info->type) {
 903         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
 904         case SNDRV_CTL_ELEM_TYPE_INTEGER:
 905         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
 906         case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
 907                 for (i = 0; i < info->count; i++) {
 908                         ret = sanity_check_int_value(card, control, info, i);
 909                         if (ret < 0)
 910                                 return ret;
 911                 }
 912                 break;
 913         default:
 914                 break;
 915         }
 916
 917         /* check whether the remaining area kept untouched */
 918         offset = value_sizes[info->type] * info->count;
 919         offset = (offset + sizeof(u32) - 1) / sizeof(u32);
 920         p = (u32 *)control->value.bytes.data + offset;
 921         for (; offset < sizeof(control->value) / sizeof(u32); offset++, p++) {
 922                 if (*p != pattern) {
 923                         ret = -EINVAL;
 924                         break;
 925                 }
 926                 *p = 0; /* clear the checked area */
 927         }
 928
 929         return ret;
 930 }
 931 #else
 932 static inline void fill_remaining_elem_value(struct snd_ctl_elem_value *control,
 933                                              struct snd_ctl_elem_info *info,
 934                                              u32 pattern)
 935 {
 936 }
 937
 938 static inline int sanity_check_elem_value(struct snd_card *card,
 939                                           struct snd_ctl_elem_value *control,
 940                                           struct snd_ctl_elem_info *info,
 941                                           u32 pattern)
 942 {
 943         return 0;
 944 }
 945 #endif
 946
 947 static int __snd_ctl_elem_info(struct snd_card *card,
 948                                struct snd_kcontrol *kctl,
 949                                struct snd_ctl_elem_info *info,
 950                                struct snd_ctl_file *ctl)
 951 {
 952         struct snd_kcontrol_volatile *vd;
 953         unsigned int index_offset;
 954         int result;
 955
 956 #ifdef CONFIG_SND_DEBUG
 957         info->access = 0;
 958 #endif
 959         result = kctl->info(kctl, info);
 960         if (result >= 0) {
 961                 snd_BUG_ON(info->access);
 962                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
 963                 vd = &kctl->vd[index_offset];
 964                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
 965                 info->access = vd->access;
 966                 if (vd->owner) {
 967                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
 968                         if (vd->owner == ctl)
 969                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
 970                         info->owner = pid_vnr(vd->owner->pid);
 971                 } else {
 972                         info->owner = -1;
 973                 }
 974                 if (!snd_ctl_skip_validation(info) &&
 975                     snd_ctl_check_elem_info(card, info) < 0)
 976                         result = -EINVAL;
 977         }
 978         return result;
 979 }
 980
 981 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 982                              struct snd_ctl_elem_info *info)
 983 {
 984         struct snd_card *card = ctl->card;
 985         struct snd_kcontrol *kctl;
 986         int result;
 987
 988         down_read(&card->controls_rwsem);
 989         kctl = snd_ctl_find_id(card, &info->id);
 990         if (kctl == NULL)
 991                 result = -ENOENT;
 992         else
 993                 result = __snd_ctl_elem_info(card, kctl, info, ctl);
 994         up_read(&card->controls_rwsem);
 995         return result;
 996 }
 997
 998 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
 999                                   struct snd_ctl_elem_info __user *_info)
1000 {
1001         struct snd_ctl_elem_info info;
1002         int result;
1003
1004         if (copy_from_user(&info, _info, sizeof(info)))
1005                 return -EFAULT;
1006         result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
1007         if (result < 0)
1008                 return result;
1009         result = snd_ctl_elem_info(ctl, &info);
1010         if (result < 0)
1011                 return result;
1012         /* drop internal access flags */
1013         info.access &= ~SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK;
1014         if (copy_to_user(_info, &info, sizeof(info)))
1015                 return -EFAULT;
1016         return result;
1017 }
1018
1019 static int snd_ctl_elem_read(struct snd_card *card,
1020                              struct snd_ctl_elem_value *control)
1021 {
1022         struct snd_kcontrol *kctl;
1023         struct snd_kcontrol_volatile *vd;
1024         unsigned int index_offset;
1025         struct snd_ctl_elem_info info;
1026         const u32 pattern = 0xdeadbeef;
1027         int ret;
1028
1029         kctl = snd_ctl_find_id(card, &control->id);
1030         if (kctl == NULL)
1031                 return -ENOENT;
1032
1033         index_offset = snd_ctl_get_ioff(kctl, &control->id);
1034         vd = &kctl->vd[index_offset];
1035         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) || kctl->get == NULL)
1036                 return -EPERM;
1037
1038         snd_ctl_build_ioff(&control->id, kctl, index_offset);
1039
1040 #ifdef CONFIG_SND_CTL_VALIDATION
1041         /* info is needed only for validation */
1042         memset(&info, 0, sizeof(info));
1043         info.id = control->id;
1044         ret = __snd_ctl_elem_info(card, kctl, &info, NULL);
1045         if (ret < 0)
1046                 return ret;
1047 #endif
1048
1049         if (!snd_ctl_skip_validation(&info))
1050                 fill_remaining_elem_value(control, &info, pattern);
1051         ret = kctl->get(kctl, control);
1052         if (ret < 0)
1053                 return ret;
1054         if (!snd_ctl_skip_validation(&info) &&
1055             sanity_check_elem_value(card, control, &info, pattern) < 0) {
1056                 dev_err(card->dev,
1057                         "control %i:%i:%i:%s:%i: access overflow\n",
1058                         control->id.iface, control->id.device,
1059                         control->id.subdevice, control->id.name,
1060                         control->id.index);
1061                 return -EINVAL;
1062         }
1063         return ret;
1064 }
1065
1066 static int snd_ctl_elem_read_user(struct snd_card *card,
1067                                   struct snd_ctl_elem_value __user *_control)
1068 {
1069         struct snd_ctl_elem_value *control;
1070         int result;
1071
1072         control = memdup_user(_control, sizeof(*control));
1073         if (IS_ERR(control))
1074                 return PTR_ERR(control);
1075
1076         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
1077         if (result < 0)
1078                 goto error;
1079
1080         down_read(&card->controls_rwsem);
1081         result = snd_ctl_elem_read(card, control);
1082         up_read(&card->controls_rwsem);
1083         if (result < 0)
1084                 goto error;
1085
1086         if (copy_to_user(_control, control, sizeof(*control)))
1087                 result = -EFAULT;
1088  error:
1089         kfree(control);
1090         return result;
1091 }
1092
1093 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
1094                               struct snd_ctl_elem_value *control)
1095 {
1096         struct snd_kcontrol *kctl;
1097         struct snd_kcontrol_volatile *vd;
1098         unsigned int index_offset;
1099         int result;
1100
1101         kctl = snd_ctl_find_id(card, &control->id);
1102         if (kctl == NULL)
1103                 return -ENOENT;
1104
1105         index_offset = snd_ctl_get_ioff(kctl, &control->id);
1106         vd = &kctl->vd[index_offset];
1107         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) || kctl->put == NULL ||
1108             (file && vd->owner && vd->owner != file)) {
1109                 return -EPERM;
1110         }
1111
1112         snd_ctl_build_ioff(&control->id, kctl, index_offset);
1113         result = kctl->put(kctl, control);
1114         if (result < 0)
1115                 return result;
1116
1117         if (result > 0) {
1118                 struct snd_ctl_elem_id id = control->id;
1119                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &id);
1120         }
1121
1122         return 0;
1123 }
1124
1125 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
1126                                    struct snd_ctl_elem_value __user *_control)
1127 {
1128         struct snd_ctl_elem_value *control;
1129         struct snd_card *card;
1130         int result;
1131
1132         control = memdup_user(_control, sizeof(*control));
1133         if (IS_ERR(control))
1134                 return PTR_ERR(control);
1135
1136         card = file->card;
1137         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
1138         if (result < 0)
1139                 goto error;
1140
1141         down_write(&card->controls_rwsem);
1142         result = snd_ctl_elem_write(card, file, control);
1143         up_write(&card->controls_rwsem);
1144         if (result < 0)
1145                 goto error;
1146
1147         if (copy_to_user(_control, control, sizeof(*control)))
1148                 result = -EFAULT;
1149  error:
1150         kfree(control);
1151         return result;
1152 }
1153
1154 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
1155                              struct snd_ctl_elem_id __user *_id)
1156 {
1157         struct snd_card *card = file->card;
1158         struct snd_ctl_elem_id id;
1159         struct snd_kcontrol *kctl;
1160         struct snd_kcontrol_volatile *vd;
1161         int result;
1162
1163         if (copy_from_user(&id, _id, sizeof(id)))
1164                 return -EFAULT;
1165         down_write(&card->controls_rwsem);
1166         kctl = snd_ctl_find_id(card, &id);
1167         if (kctl == NULL) {
1168                 result = -ENOENT;
1169         } else {
1170                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1171                 if (vd->owner != NULL)
1172                         result = -EBUSY;
1173                 else {
1174                         vd->owner = file;
1175                         result = 0;
1176                 }
1177         }
1178         up_write(&card->controls_rwsem);
1179         return result;
1180 }
1181
1182 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
1183                                struct snd_ctl_elem_id __user *_id)
1184 {
1185         struct snd_card *card = file->card;
1186         struct snd_ctl_elem_id id;
1187         struct snd_kcontrol *kctl;
1188         struct snd_kcontrol_volatile *vd;
1189         int result;
1190
1191         if (copy_from_user(&id, _id, sizeof(id)))
1192                 return -EFAULT;
1193         down_write(&card->controls_rwsem);
1194         kctl = snd_ctl_find_id(card, &id);
1195         if (kctl == NULL) {
1196                 result = -ENOENT;
1197         } else {
1198                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1199                 if (vd->owner == NULL)
1200                         result = -EINVAL;
1201                 else if (vd->owner != file)
1202                         result = -EPERM;
1203                 else {
1204                         vd->owner = NULL;
1205                         result = 0;
1206                 }
1207         }
1208         up_write(&card->controls_rwsem);
1209         return result;
1210 }
1211
1212 struct user_element {
1213         struct snd_ctl_elem_info info;
1214         struct snd_card *card;
1215         char *elem_data;                /* element data */
1216         unsigned long elem_data_size;   /* size of element data in bytes */
1217         void *tlv_data;                 /* TLV data */
1218         unsigned long tlv_data_size;    /* TLV data size */
1219         void *priv_data;                /* private data (like strings for enumerated type) */
1220 };
1221
1222 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1223                                   struct snd_ctl_elem_info *uinfo)
1224 {
1225         struct user_element *ue = kcontrol->private_data;
1226         unsigned int offset;
1227
1228         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1229         *uinfo = ue->info;
1230         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1231
1232         return 0;
1233 }
1234
1235 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1236                                        struct snd_ctl_elem_info *uinfo)
1237 {
1238         struct user_element *ue = kcontrol->private_data;
1239         const char *names;
1240         unsigned int item;
1241         unsigned int offset;
1242
1243         item = uinfo->value.enumerated.item;
1244
1245         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1246         *uinfo = ue->info;
1247         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1248
1249         item = min(item, uinfo->value.enumerated.items - 1);
1250         uinfo->value.enumerated.item = item;
1251
1252         names = ue->priv_data;
1253         for (; item > 0; --item)
1254                 names += strlen(names) + 1;
1255         strcpy(uinfo->value.enumerated.name, names);
1256
1257         return 0;
1258 }
1259
1260 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1261                                  struct snd_ctl_elem_value *ucontrol)
1262 {
1263         struct user_element *ue = kcontrol->private_data;
1264         unsigned int size = ue->elem_data_size;
1265         char *src = ue->elem_data +
1266                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1267
1268         memcpy(&ucontrol->value, src, size);
1269         return 0;
1270 }
1271
1272 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1273                                  struct snd_ctl_elem_value *ucontrol)
1274 {
1275         int change;
1276         struct user_element *ue = kcontrol->private_data;
1277         unsigned int size = ue->elem_data_size;
1278         char *dst = ue->elem_data +
1279                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1280
1281         change = memcmp(&ucontrol->value, dst, size) != 0;
1282         if (change)
1283                 memcpy(dst, &ucontrol->value, size);
1284         return change;
1285 }
1286
1287 static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1288                             unsigned int size)
1289 {
1290         struct user_element *ue = kctl->private_data;
1291         unsigned int *container;
1292         struct snd_ctl_elem_id id;
1293         unsigned int mask = 0;
1294         int i;
1295         int change;
1296
1297         if (size > 1024 * 128)  /* sane value */
1298                 return -EINVAL;
1299
1300         container = vmemdup_user(buf, size);
1301         if (IS_ERR(container))
1302                 return PTR_ERR(container);
1303
1304         change = ue->tlv_data_size != size;
1305         if (!change)
1306                 change = memcmp(ue->tlv_data, container, size) != 0;
1307         if (!change) {
1308                 kvfree(container);
1309                 return 0;
1310         }
1311
1312         if (ue->tlv_data == NULL) {
1313                 /* Now TLV data is available. */
1314                 for (i = 0; i < kctl->count; ++i)
1315                         kctl->vd[i].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
1316                 mask = SNDRV_CTL_EVENT_MASK_INFO;
1317         }
1318
1319         kvfree(ue->tlv_data);
1320         ue->tlv_data = container;
1321         ue->tlv_data_size = size;
1322
1323         mask |= SNDRV_CTL_EVENT_MASK_TLV;
1324         for (i = 0; i < kctl->count; ++i) {
1325                 snd_ctl_build_ioff(&id, kctl, i);
1326                 snd_ctl_notify(ue->card, mask, &id);
1327         }
1328
1329         return change;
1330 }
1331
1332 static int read_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1333                          unsigned int size)
1334 {
1335         struct user_element *ue = kctl->private_data;
1336
1337         if (ue->tlv_data_size == 0 || ue->tlv_data == NULL)
1338                 return -ENXIO;
1339
1340         if (size < ue->tlv_data_size)
1341                 return -ENOSPC;
1342
1343         if (copy_to_user(buf, ue->tlv_data, ue->tlv_data_size))
1344                 return -EFAULT;
1345
1346         return 0;
1347 }
1348
1349 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kctl, int op_flag,
1350                                  unsigned int size, unsigned int __user *buf)
1351 {
1352         if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
1353                 return replace_user_tlv(kctl, buf, size);
1354         else
1355                 return read_user_tlv(kctl, buf, size);
1356 }
1357
1358 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1359 {
1360         char *names, *p;
1361         size_t buf_len, name_len;
1362         unsigned int i;
1363         const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1364
1365         if (ue->info.value.enumerated.names_length > 64 * 1024)
1366                 return -EINVAL;
1367
1368         names = vmemdup_user((const void __user *)user_ptrval,
1369                 ue->info.value.enumerated.names_length);
1370         if (IS_ERR(names))
1371                 return PTR_ERR(names);
1372
1373         /* check that there are enough valid names */
1374         buf_len = ue->info.value.enumerated.names_length;
1375         p = names;
1376         for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1377                 name_len = strnlen(p, buf_len);
1378                 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1379                         kvfree(names);
1380                         return -EINVAL;
1381                 }
1382                 p += name_len + 1;
1383                 buf_len -= name_len + 1;
1384         }
1385
1386         ue->priv_data = names;
1387         ue->info.value.enumerated.names_ptr = 0;
1388
1389         return 0;
1390 }
1391
1392 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1393 {
1394         struct user_element *ue = kcontrol->private_data;
1395
1396         kvfree(ue->tlv_data);
1397         kvfree(ue->priv_data);
1398         kfree(ue);
1399 }
1400
1401 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1402                             struct snd_ctl_elem_info *info, int replace)
1403 {
1404         struct snd_card *card = file->card;
1405         struct snd_kcontrol *kctl;
1406         unsigned int count;
1407         unsigned int access;
1408         long private_size;
1409         struct user_element *ue;
1410         unsigned int offset;
1411         int err;
1412
1413         if (!*info->id.name)
1414                 return -EINVAL;
1415         if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
1416                 return -EINVAL;
1417
1418         /* Delete a control to replace them if needed. */
1419         if (replace) {
1420                 info->id.numid = 0;
1421                 err = snd_ctl_remove_user_ctl(file, &info->id);
1422                 if (err)
1423                         return err;
1424         }
1425
1426         /*
1427          * The number of userspace controls are counted control by control,
1428          * not element by element.
1429          */
1430         if (card->user_ctl_count + 1 > MAX_USER_CONTROLS)
1431                 return -ENOMEM;
1432
1433         /* Check the number of elements for this userspace control. */
1434         count = info->owner;
1435         if (count == 0)
1436                 count = 1;
1437
1438         /* Arrange access permissions if needed. */
1439         access = info->access;
1440         if (access == 0)
1441                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
1442         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
1443                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
1444                    SNDRV_CTL_ELEM_ACCESS_TLV_WRITE);
1445
1446         /* In initial state, nothing is available as TLV container. */
1447         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1448                 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1449         access |= SNDRV_CTL_ELEM_ACCESS_USER;
1450
1451         /*
1452          * Check information and calculate the size of data specific to
1453          * this userspace control.
1454          */
1455         /* pass NULL to card for suppressing error messages */
1456         err = snd_ctl_check_elem_info(NULL, info);
1457         if (err < 0)
1458                 return err;
1459         /* user-space control doesn't allow zero-size data */
1460         if (info->count < 1)
1461                 return -EINVAL;
1462         private_size = value_sizes[info->type] * info->count;
1463
1464         /*
1465          * Keep memory object for this userspace control. After passing this
1466          * code block, the instance should be freed by snd_ctl_free_one().
1467          *
1468          * Note that these elements in this control are locked.
1469          */
1470         err = snd_ctl_new(&kctl, count, access, file);
1471         if (err < 0)
1472                 return err;
1473         memcpy(&kctl->id, &info->id, sizeof(kctl->id));
1474         kctl->private_data = kzalloc(sizeof(struct user_element) + private_size * count,
1475                                      GFP_KERNEL);
1476         if (kctl->private_data == NULL) {
1477                 kfree(kctl);
1478                 return -ENOMEM;
1479         }
1480         kctl->private_free = snd_ctl_elem_user_free;
1481
1482         /* Set private data for this userspace control. */
1483         ue = (struct user_element *)kctl->private_data;
1484         ue->card = card;
1485         ue->info = *info;
1486         ue->info.access = 0;
1487         ue->elem_data = (char *)ue + sizeof(*ue);
1488         ue->elem_data_size = private_size;
1489         if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1490                 err = snd_ctl_elem_init_enum_names(ue);
1491                 if (err < 0) {
1492                         snd_ctl_free_one(kctl);
1493                         return err;
1494                 }
1495         }
1496
1497         /* Set callback functions. */
1498         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1499                 kctl->info = snd_ctl_elem_user_enum_info;
1500         else
1501                 kctl->info = snd_ctl_elem_user_info;
1502         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1503                 kctl->get = snd_ctl_elem_user_get;
1504         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1505                 kctl->put = snd_ctl_elem_user_put;
1506         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1507                 kctl->tlv.c = snd_ctl_elem_user_tlv;
1508
1509         /* This function manage to free the instance on failure. */
1510         down_write(&card->controls_rwsem);
1511         err = __snd_ctl_add_replace(card, kctl, CTL_ADD_EXCLUSIVE);
1512         if (err < 0) {
1513                 snd_ctl_free_one(kctl);
1514                 goto unlock;
1515         }
1516         offset = snd_ctl_get_ioff(kctl, &info->id);
1517         snd_ctl_build_ioff(&info->id, kctl, offset);
1518         /*
1519          * Here we cannot fill any field for the number of elements added by
1520          * this operation because there're no specific fields. The usage of
1521          * 'owner' field for this purpose may cause any bugs to userspace
1522          * applications because the field originally means PID of a process
1523          * which locks the element.
1524          */
1525
1526         card->user_ctl_count++;
1527
1528  unlock:
1529         up_write(&card->controls_rwsem);
1530         return 0;
1531 }
1532
1533 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1534                                  struct snd_ctl_elem_info __user *_info, int replace)
1535 {
1536         struct snd_ctl_elem_info info;
1537         int err;
1538
1539         if (copy_from_user(&info, _info, sizeof(info)))
1540                 return -EFAULT;
1541         err = snd_ctl_elem_add(file, &info, replace);
1542         if (err < 0)
1543                 return err;
1544         if (copy_to_user(_info, &info, sizeof(info))) {
1545                 snd_ctl_remove_user_ctl(file, &info.id);
1546                 return -EFAULT;
1547         }
1548
1549         return 0;
1550 }
1551
1552 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1553                                struct snd_ctl_elem_id __user *_id)
1554 {
1555         struct snd_ctl_elem_id id;
1556
1557         if (copy_from_user(&id, _id, sizeof(id)))
1558                 return -EFAULT;
1559         return snd_ctl_remove_user_ctl(file, &id);
1560 }
1561
1562 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1563 {
1564         int subscribe;
1565         if (get_user(subscribe, ptr))
1566                 return -EFAULT;
1567         if (subscribe < 0) {
1568                 subscribe = file->subscribed;
1569                 if (put_user(subscribe, ptr))
1570                         return -EFAULT;
1571                 return 0;
1572         }
1573         if (subscribe) {
1574                 file->subscribed = 1;
1575                 return 0;
1576         } else if (file->subscribed) {
1577                 snd_ctl_empty_read_queue(file);
1578                 file->subscribed = 0;
1579         }
1580         return 0;
1581 }
1582
1583 static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,
1584                             struct snd_kcontrol *kctl,
1585                             struct snd_ctl_elem_id *id,
1586                             unsigned int __user *buf, unsigned int size)
1587 {
1588         static const struct {
1589                 int op;
1590                 int perm;
1591         } pairs[] = {
1592                 {SNDRV_CTL_TLV_OP_READ,  SNDRV_CTL_ELEM_ACCESS_TLV_READ},
1593                 {SNDRV_CTL_TLV_OP_WRITE, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE},
1594                 {SNDRV_CTL_TLV_OP_CMD,   SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},
1595         };
1596         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1597         int i;
1598
1599         /* Check support of the request for this element. */
1600         for (i = 0; i < ARRAY_SIZE(pairs); ++i) {
1601                 if (op_flag == pairs[i].op && (vd->access & pairs[i].perm))
1602                         break;
1603         }
1604         if (i == ARRAY_SIZE(pairs))
1605                 return -ENXIO;
1606
1607         if (kctl->tlv.c == NULL)
1608                 return -ENXIO;
1609
1610         /* Write and command operations are not allowed for locked element. */
1611         if (op_flag != SNDRV_CTL_TLV_OP_READ &&
1612             vd->owner != NULL && vd->owner != file)
1613                 return -EPERM;
1614
1615         return kctl->tlv.c(kctl, op_flag, size, buf);
1616 }
1617
1618 static int read_tlv_buf(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id,
1619                         unsigned int __user *buf, unsigned int size)
1620 {
1621         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1622         unsigned int len;
1623
1624         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ))
1625                 return -ENXIO;
1626
1627         if (kctl->tlv.p == NULL)
1628                 return -ENXIO;
1629
1630         len = sizeof(unsigned int) * 2 + kctl->tlv.p[1];
1631         if (size < len)
1632                 return -ENOMEM;
1633
1634         if (copy_to_user(buf, kctl->tlv.p, len))
1635                 return -EFAULT;
1636
1637         return 0;
1638 }
1639
1640 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1641                              struct snd_ctl_tlv __user *buf,
1642                              int op_flag)
1643 {
1644         struct snd_ctl_tlv header;
1645         unsigned int __user *container;
1646         unsigned int container_size;
1647         struct snd_kcontrol *kctl;
1648         struct snd_ctl_elem_id id;
1649         struct snd_kcontrol_volatile *vd;
1650
1651         if (copy_from_user(&header, buf, sizeof(header)))
1652                 return -EFAULT;
1653
1654         /* In design of control core, numerical ID starts at 1. */
1655         if (header.numid == 0)
1656                 return -EINVAL;
1657
1658         /* At least, container should include type and length fields.  */
1659         if (header.length < sizeof(unsigned int) * 2)
1660                 return -EINVAL;
1661         container_size = header.length;
1662         container = buf->tlv;
1663
1664         kctl = snd_ctl_find_numid(file->card, header.numid);
1665         if (kctl == NULL)
1666                 return -ENOENT;
1667
1668         /* Calculate index of the element in this set. */
1669         id = kctl->id;
1670         snd_ctl_build_ioff(&id, kctl, header.numid - id.numid);
1671         vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1672
1673         if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1674                 return call_tlv_handler(file, op_flag, kctl, &id, container,
1675                                         container_size);
1676         } else {
1677                 if (op_flag == SNDRV_CTL_TLV_OP_READ) {
1678                         return read_tlv_buf(kctl, &id, container,
1679                                             container_size);
1680                 }
1681         }
1682
1683         /* Not supported. */
1684         return -ENXIO;
1685 }
1686
1687 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1688 {
1689         struct snd_ctl_file *ctl;
1690         struct snd_card *card;
1691         struct snd_kctl_ioctl *p;
1692         void __user *argp = (void __user *)arg;
1693         int __user *ip = argp;
1694         int err;
1695
1696         ctl = file->private_data;
1697         card = ctl->card;
1698         if (snd_BUG_ON(!card))
1699                 return -ENXIO;
1700         switch (cmd) {
1701         case SNDRV_CTL_IOCTL_PVERSION:
1702                 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1703         case SNDRV_CTL_IOCTL_CARD_INFO:
1704                 return snd_ctl_card_info(card, ctl, cmd, argp);
1705         case SNDRV_CTL_IOCTL_ELEM_LIST:
1706                 return snd_ctl_elem_list(card, argp);
1707         case SNDRV_CTL_IOCTL_ELEM_INFO:
1708                 return snd_ctl_elem_info_user(ctl, argp);
1709         case SNDRV_CTL_IOCTL_ELEM_READ:
1710                 return snd_ctl_elem_read_user(card, argp);
1711         case SNDRV_CTL_IOCTL_ELEM_WRITE:
1712                 return snd_ctl_elem_write_user(ctl, argp);
1713         case SNDRV_CTL_IOCTL_ELEM_LOCK:
1714                 return snd_ctl_elem_lock(ctl, argp);
1715         case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1716                 return snd_ctl_elem_unlock(ctl, argp);
1717         case SNDRV_CTL_IOCTL_ELEM_ADD:
1718                 return snd_ctl_elem_add_user(ctl, argp, 0);
1719         case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1720                 return snd_ctl_elem_add_user(ctl, argp, 1);
1721         case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1722                 return snd_ctl_elem_remove(ctl, argp);
1723         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1724                 return snd_ctl_subscribe_events(ctl, ip);
1725         case SNDRV_CTL_IOCTL_TLV_READ:
1726                 down_read(&ctl->card->controls_rwsem);
1727                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
1728                 up_read(&ctl->card->controls_rwsem);
1729                 return err;
1730         case SNDRV_CTL_IOCTL_TLV_WRITE:
1731                 down_write(&ctl->card->controls_rwsem);
1732                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
1733                 up_write(&ctl->card->controls_rwsem);
1734                 return err;
1735         case SNDRV_CTL_IOCTL_TLV_COMMAND:
1736                 down_write(&ctl->card->controls_rwsem);
1737                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
1738                 up_write(&ctl->card->controls_rwsem);
1739                 return err;
1740         case SNDRV_CTL_IOCTL_POWER:
1741                 return -ENOPROTOOPT;
1742         case SNDRV_CTL_IOCTL_POWER_STATE:
1743 #ifdef CONFIG_PM
1744                 return put_user(card->power_state, ip) ? -EFAULT : 0;
1745 #else
1746                 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1747 #endif
1748         }
1749         down_read(&snd_ioctl_rwsem);
1750         list_for_each_entry(p, &snd_control_ioctls, list) {
1751                 err = p->fioctl(card, ctl, cmd, arg);
1752                 if (err != -ENOIOCTLCMD) {
1753                         up_read(&snd_ioctl_rwsem);
1754                         return err;
1755                 }
1756         }
1757         up_read(&snd_ioctl_rwsem);
1758         dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
1759         return -ENOTTY;
1760 }
1761
1762 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1763                             size_t count, loff_t * offset)
1764 {
1765         struct snd_ctl_file *ctl;
1766         int err = 0;
1767         ssize_t result = 0;
1768
1769         ctl = file->private_data;
1770         if (snd_BUG_ON(!ctl || !ctl->card))
1771                 return -ENXIO;
1772         if (!ctl->subscribed)
1773                 return -EBADFD;
1774         if (count < sizeof(struct snd_ctl_event))
1775                 return -EINVAL;
1776         spin_lock_irq(&ctl->read_lock);
1777         while (count >= sizeof(struct snd_ctl_event)) {
1778                 struct snd_ctl_event ev;
1779                 struct snd_kctl_event *kev;
1780                 while (list_empty(&ctl->events)) {
1781                         wait_queue_entry_t wait;
1782                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1783                                 err = -EAGAIN;
1784                                 goto __end_lock;
1785                         }
1786                         init_waitqueue_entry(&wait, current);
1787                         add_wait_queue(&ctl->change_sleep, &wait);
1788                         set_current_state(TASK_INTERRUPTIBLE);
1789                         spin_unlock_irq(&ctl->read_lock);
1790                         schedule();
1791                         remove_wait_queue(&ctl->change_sleep, &wait);
1792                         if (ctl->card->shutdown)
1793                                 return -ENODEV;
1794                         if (signal_pending(current))
1795                                 return -ERESTARTSYS;
1796                         spin_lock_irq(&ctl->read_lock);
1797                 }
1798                 kev = snd_kctl_event(ctl->events.next);
1799                 ev.type = SNDRV_CTL_EVENT_ELEM;
1800                 ev.data.elem.mask = kev->mask;
1801                 ev.data.elem.id = kev->id;
1802                 list_del(&kev->list);
1803                 spin_unlock_irq(&ctl->read_lock);
1804                 kfree(kev);
1805                 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1806                         err = -EFAULT;
1807                         goto __end;
1808                 }
1809                 spin_lock_irq(&ctl->read_lock);
1810                 buffer += sizeof(struct snd_ctl_event);
1811                 count -= sizeof(struct snd_ctl_event);
1812                 result += sizeof(struct snd_ctl_event);
1813         }
1814       __end_lock:
1815         spin_unlock_irq(&ctl->read_lock);
1816       __end:
1817         return result > 0 ? result : err;
1818 }
1819
1820 static __poll_t snd_ctl_poll(struct file *file, poll_table * wait)
1821 {
1822         __poll_t mask;
1823         struct snd_ctl_file *ctl;
1824
1825         ctl = file->private_data;
1826         if (!ctl->subscribed)
1827                 return 0;
1828         poll_wait(file, &ctl->change_sleep, wait);
1829
1830         mask = 0;
1831         if (!list_empty(&ctl->events))
1832                 mask |= EPOLLIN | EPOLLRDNORM;
1833
1834         return mask;
1835 }
1836
1837 /*
1838  * register the device-specific control-ioctls.
1839  * called from each device manager like pcm.c, hwdep.c, etc.
1840  */
1841 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1842 {
1843         struct snd_kctl_ioctl *pn;
1844
1845         pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1846         if (pn == NULL)
1847                 return -ENOMEM;
1848         pn->fioctl = fcn;
1849         down_write(&snd_ioctl_rwsem);
1850         list_add_tail(&pn->list, lists);
1851         up_write(&snd_ioctl_rwsem);
1852         return 0;
1853 }
1854
1855 /**
1856  * snd_ctl_register_ioctl - register the device-specific control-ioctls
1857  * @fcn: ioctl callback function
1858  *
1859  * called from each device manager like pcm.c, hwdep.c, etc.
1860  */
1861 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1862 {
1863         return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1864 }
1865 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1866
1867 #ifdef CONFIG_COMPAT
1868 /**
1869  * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
1870  * control-ioctls
1871  * @fcn: ioctl callback function
1872  */
1873 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1874 {
1875         return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1876 }
1877 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1878 #endif
1879
1880 /*
1881  * de-register the device-specific control-ioctls.
1882  */
1883 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1884                                      struct list_head *lists)
1885 {
1886         struct snd_kctl_ioctl *p;
1887
1888         if (snd_BUG_ON(!fcn))
1889                 return -EINVAL;
1890         down_write(&snd_ioctl_rwsem);
1891         list_for_each_entry(p, lists, list) {
1892                 if (p->fioctl == fcn) {
1893                         list_del(&p->list);
1894                         up_write(&snd_ioctl_rwsem);
1895                         kfree(p);
1896                         return 0;
1897                 }
1898         }
1899         up_write(&snd_ioctl_rwsem);
1900         snd_BUG();
1901         return -EINVAL;
1902 }
1903
1904 /**
1905  * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
1906  * @fcn: ioctl callback function to unregister
1907  */
1908 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1909 {
1910         return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1911 }
1912 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1913
1914 #ifdef CONFIG_COMPAT
1915 /**
1916  * snd_ctl_unregister_ioctl - de-register the device-specific compat 32bit
1917  * control-ioctls
1918  * @fcn: ioctl callback function to unregister
1919  */
1920 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1921 {
1922         return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1923 }
1924 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1925 #endif
1926
1927 static int snd_ctl_fasync(int fd, struct file * file, int on)
1928 {
1929         struct snd_ctl_file *ctl;
1930
1931         ctl = file->private_data;
1932         return fasync_helper(fd, file, on, &ctl->fasync);
1933 }
1934
1935 /* return the preferred subdevice number if already assigned;
1936  * otherwise return -1
1937  */
1938 int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
1939 {
1940         struct snd_ctl_file *kctl;
1941         int subdevice = -1;
1942
1943         read_lock(&card->ctl_files_rwlock);
1944         list_for_each_entry(kctl, &card->ctl_files, list) {
1945                 if (kctl->pid == task_pid(current)) {
1946                         subdevice = kctl->preferred_subdevice[type];
1947                         if (subdevice != -1)
1948                                 break;
1949                 }
1950         }
1951         read_unlock(&card->ctl_files_rwlock);
1952         return subdevice;
1953 }
1954 EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
1955
1956 /*
1957  * ioctl32 compat
1958  */
1959 #ifdef CONFIG_COMPAT
1960 #include "control_compat.c"
1961 #else
1962 #define snd_ctl_ioctl_compat    NULL
1963 #endif
1964
1965 /*
1966  *  INIT PART
1967  */
1968
1969 static const struct file_operations snd_ctl_f_ops =
1970 {
1971         .owner =        THIS_MODULE,
1972         .read =         snd_ctl_read,
1973         .open =         snd_ctl_open,
1974         .release =      snd_ctl_release,
1975         .llseek =       no_llseek,
1976         .poll =         snd_ctl_poll,
1977         .unlocked_ioctl =       snd_ctl_ioctl,
1978         .compat_ioctl = snd_ctl_ioctl_compat,
1979         .fasync =       snd_ctl_fasync,
1980 };
1981
1982 /*
1983  * registration of the control device
1984  */
1985 static int snd_ctl_dev_register(struct snd_device *device)
1986 {
1987         struct snd_card *card = device->device_data;
1988
1989         return snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
1990                                    &snd_ctl_f_ops, card, &card->ctl_dev);
1991 }
1992
1993 /*
1994  * disconnection of the control device
1995  */
1996 static int snd_ctl_dev_disconnect(struct snd_device *device)
1997 {
1998         struct snd_card *card = device->device_data;
1999         struct snd_ctl_file *ctl;
2000
2001         read_lock(&card->ctl_files_rwlock);
2002         list_for_each_entry(ctl, &card->ctl_files, list) {
2003                 wake_up(&ctl->change_sleep);
2004                 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
2005         }
2006         read_unlock(&card->ctl_files_rwlock);
2007
2008         return snd_unregister_device(&card->ctl_dev);
2009 }
2010
2011 /*
2012  * free all controls
2013  */
2014 static int snd_ctl_dev_free(struct snd_device *device)
2015 {
2016         struct snd_card *card = device->device_data;
2017         struct snd_kcontrol *control;
2018
2019         down_write(&card->controls_rwsem);
2020         while (!list_empty(&card->controls)) {
2021                 control = snd_kcontrol(card->controls.next);
2022                 snd_ctl_remove(card, control);
2023         }
2024         up_write(&card->controls_rwsem);
2025         put_device(&card->ctl_dev);
2026         return 0;
2027 }
2028
2029 /*
2030  * create control core:
2031  * called from init.c
2032  */
2033 int snd_ctl_create(struct snd_card *card)
2034 {
2035         static const struct snd_device_ops ops = {
2036                 .dev_free = snd_ctl_dev_free,
2037                 .dev_register = snd_ctl_dev_register,
2038                 .dev_disconnect = snd_ctl_dev_disconnect,
2039         };
2040         int err;
2041
2042         if (snd_BUG_ON(!card))
2043                 return -ENXIO;
2044         if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))
2045                 return -ENXIO;
2046
2047         snd_device_initialize(&card->ctl_dev, card);
2048         dev_set_name(&card->ctl_dev, "controlC%d", card->number);
2049
2050         err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
2051         if (err < 0)
2052                 put_device(&card->ctl_dev);
2053         return err;
2054 }
2055
2056 /*
2057  * Frequently used control callbacks/helpers
2058  */
2059
2060 /**
2061  * snd_ctl_boolean_mono_info - Helper function for a standard boolean info
2062  * callback with a mono channel
2063  * @kcontrol: the kcontrol instance
2064  * @uinfo: info to store
2065  *
2066  * This is a function that can be used as info callback for a standard
2067  * boolean control with a single mono channel.
2068  */
2069 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
2070                               struct snd_ctl_elem_info *uinfo)
2071 {
2072         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
2073         uinfo->count = 1;
2074         uinfo->value.integer.min = 0;
2075         uinfo->value.integer.max = 1;
2076         return 0;
2077 }
2078 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
2079
2080 /**
2081  * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
2082  * callback with stereo two channels
2083  * @kcontrol: the kcontrol instance
2084  * @uinfo: info to store
2085  *
2086  * This is a function that can be used as info callback for a standard
2087  * boolean control with stereo two channels.
2088  */
2089 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
2090                                 struct snd_ctl_elem_info *uinfo)
2091 {
2092         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
2093         uinfo->count = 2;
2094         uinfo->value.integer.min = 0;
2095         uinfo->value.integer.max = 1;
2096         return 0;
2097 }
2098 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
2099
2100 /**
2101  * snd_ctl_enum_info - fills the info structure for an enumerated control
2102  * @info: the structure to be filled
2103  * @channels: the number of the control's channels; often one
2104  * @items: the number of control values; also the size of @names
2105  * @names: an array containing the names of all control values
2106  *
2107  * Sets all required fields in @info to their appropriate values.
2108  * If the control's accessibility is not the default (readable and writable),
2109  * the caller has to fill @info->access.
2110  *
2111  * Return: Zero.
2112  */
2113 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
2114                       unsigned int items, const char *const names[])
2115 {
2116         info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
2117         info->count = channels;
2118         info->value.enumerated.items = items;
2119         if (!items)
2120                 return 0;
2121         if (info->value.enumerated.item >= items)
2122                 info->value.enumerated.item = items - 1;
2123         WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),
2124              "ALSA: too long item name '%s'\n",
2125              names[info->value.enumerated.item]);
2126         strlcpy(info->value.enumerated.name,
2127                 names[info->value.enumerated.item],
2128                 sizeof(info->value.enumerated.name));
2129         return 0;
2130 }
2131 EXPORT_SYMBOL(snd_ctl_enum_info);