sound/core/control.c

   1 /*
   2  *  Routines for driver control interface
   3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   4  *
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19  *
  20  */
  21
  22 #include <linux/threads.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/module.h>
  25 #include <linux/slab.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/time.h>
  28 #include <linux/mm.h>
  29 #include <linux/sched/signal.h>
  30 #include <sound/core.h>
  31 #include <sound/minors.h>
  32 #include <sound/info.h>
  33 #include <sound/control.h>
  34
  35 /* max number of user-defined controls */
  36 #define MAX_USER_CONTROLS       32
  37 #define MAX_CONTROL_COUNT       1028
  38
  39 struct snd_kctl_ioctl {
  40         struct list_head list;          /* list of all ioctls */
  41         snd_kctl_ioctl_func_t fioctl;
  42 };
  43
  44 static DECLARE_RWSEM(snd_ioctl_rwsem);
  45 static LIST_HEAD(snd_control_ioctls);
  46 #ifdef CONFIG_COMPAT
  47 static LIST_HEAD(snd_control_compat_ioctls);
  48 #endif
  49
  50 static int snd_ctl_open(struct inode *inode, struct file *file)
  51 {
  52         unsigned long flags;
  53         struct snd_card *card;
  54         struct snd_ctl_file *ctl;
  55         int i, err;
  56
  57         err = nonseekable_open(inode, file);
  58         if (err < 0)
  59                 return err;
  60
  61         card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
  62         if (!card) {
  63                 err = -ENODEV;
  64                 goto __error1;
  65         }
  66         err = snd_card_file_add(card, file);
  67         if (err < 0) {
  68                 err = -ENODEV;
  69                 goto __error1;
  70         }
  71         if (!try_module_get(card->module)) {
  72                 err = -EFAULT;
  73                 goto __error2;
  74         }
  75         ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
  76         if (ctl == NULL) {
  77                 err = -ENOMEM;
  78                 goto __error;
  79         }
  80         INIT_LIST_HEAD(&ctl->events);
  81         init_waitqueue_head(&ctl->change_sleep);
  82         spin_lock_init(&ctl->read_lock);
  83         ctl->card = card;
  84         for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
  85                 ctl->preferred_subdevice[i] = -1;
  86         ctl->pid = get_pid(task_pid(current));
  87         file->private_data = ctl;
  88         write_lock_irqsave(&card->ctl_files_rwlock, flags);
  89         list_add_tail(&ctl->list, &card->ctl_files);
  90         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
  91         snd_card_unref(card);
  92         return 0;
  93
  94       __error:
  95         module_put(card->module);
  96       __error2:
  97         snd_card_file_remove(card, file);
  98       __error1:
  99         if (card)
 100                 snd_card_unref(card);
 101         return err;
 102 }
 103
 104 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
 105 {
 106         unsigned long flags;
 107         struct snd_kctl_event *cread;
 108
 109         spin_lock_irqsave(&ctl->read_lock, flags);
 110         while (!list_empty(&ctl->events)) {
 111                 cread = snd_kctl_event(ctl->events.next);
 112                 list_del(&cread->list);
 113                 kfree(cread);
 114         }
 115         spin_unlock_irqrestore(&ctl->read_lock, flags);
 116 }
 117
 118 static int snd_ctl_release(struct inode *inode, struct file *file)
 119 {
 120         unsigned long flags;
 121         struct snd_card *card;
 122         struct snd_ctl_file *ctl;
 123         struct snd_kcontrol *control;
 124         unsigned int idx;
 125
 126         ctl = file->private_data;
 127         file->private_data = NULL;
 128         card = ctl->card;
 129         write_lock_irqsave(&card->ctl_files_rwlock, flags);
 130         list_del(&ctl->list);
 131         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 132         down_write(&card->controls_rwsem);
 133         list_for_each_entry(control, &card->controls, list)
 134                 for (idx = 0; idx < control->count; idx++)
 135                         if (control->vd[idx].owner == ctl)
 136                                 control->vd[idx].owner = NULL;
 137         up_write(&card->controls_rwsem);
 138         snd_ctl_empty_read_queue(ctl);
 139         put_pid(ctl->pid);
 140         kfree(ctl);
 141         module_put(card->module);
 142         snd_card_file_remove(card, file);
 143         return 0;
 144 }
 145
 146 /**
 147  * snd_ctl_notify - Send notification to user-space for a control change
 148  * @card: the card to send notification
 149  * @mask: the event mask, SNDRV_CTL_EVENT_*
 150  * @id: the ctl element id to send notification
 151  *
 152  * This function adds an event record with the given id and mask, appends
 153  * to the list and wakes up the user-space for notification.  This can be
 154  * called in the atomic context.
 155  */
 156 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 157                     struct snd_ctl_elem_id *id)
 158 {
 159         unsigned long flags;
 160         struct snd_ctl_file *ctl;
 161         struct snd_kctl_event *ev;
 162
 163         if (snd_BUG_ON(!card || !id))
 164                 return;
 165         if (card->shutdown)
 166                 return;
 167         read_lock(&card->ctl_files_rwlock);
 168 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 169         card->mixer_oss_change_count++;
 170 #endif
 171         list_for_each_entry(ctl, &card->ctl_files, list) {
 172                 if (!ctl->subscribed)
 173                         continue;
 174                 spin_lock_irqsave(&ctl->read_lock, flags);
 175                 list_for_each_entry(ev, &ctl->events, list) {
 176                         if (ev->id.numid == id->numid) {
 177                                 ev->mask |= mask;
 178                                 goto _found;
 179                         }
 180                 }
 181                 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
 182                 if (ev) {
 183                         ev->id = *id;
 184                         ev->mask = mask;
 185                         list_add_tail(&ev->list, &ctl->events);
 186                 } else {
 187                         dev_err(card->dev, "No memory available to allocate event\n");
 188                 }
 189         _found:
 190                 wake_up(&ctl->change_sleep);
 191                 spin_unlock_irqrestore(&ctl->read_lock, flags);
 192                 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
 193         }
 194         read_unlock(&card->ctl_files_rwlock);
 195 }
 196 EXPORT_SYMBOL(snd_ctl_notify);
 197
 198 /**
 199  * snd_ctl_new - create a new control instance with some elements
 200  * @kctl: the pointer to store new control instance
 201  * @count: the number of elements in this control
 202  * @access: the default access flags for elements in this control
 203  * @file: given when locking these elements
 204  *
 205  * Allocates a memory object for a new control instance. The instance has
 206  * elements as many as the given number (@count). Each element has given
 207  * access permissions (@access). Each element is locked when @file is given.
 208  *
 209  * Return: 0 on success, error code on failure
 210  */
 211 static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,
 212                        unsigned int access, struct snd_ctl_file *file)
 213 {
 214         unsigned int size;
 215         unsigned int idx;
 216
 217         if (count == 0 || count > MAX_CONTROL_COUNT)
 218                 return -EINVAL;
 219
 220         size  = sizeof(struct snd_kcontrol);
 221         size += sizeof(struct snd_kcontrol_volatile) * count;
 222
 223         *kctl = kzalloc(size, GFP_KERNEL);
 224         if (!*kctl)
 225                 return -ENOMEM;
 226
 227         for (idx = 0; idx < count; idx++) {
 228                 (*kctl)->vd[idx].access = access;
 229                 (*kctl)->vd[idx].owner = file;
 230         }
 231         (*kctl)->count = count;
 232
 233         return 0;
 234 }
 235
 236 /**
 237  * snd_ctl_new1 - create a control instance from the template
 238  * @ncontrol: the initialization record
 239  * @private_data: the private data to set
 240  *
 241  * Allocates a new struct snd_kcontrol instance and initialize from the given
 242  * template.  When the access field of ncontrol is 0, it's assumed as
 243  * READWRITE access. When the count field is 0, it's assumes as one.
 244  *
 245  * Return: The pointer of the newly generated instance, or %NULL on failure.
 246  */
 247 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
 248                                   void *private_data)
 249 {
 250         struct snd_kcontrol *kctl;
 251         unsigned int count;
 252         unsigned int access;
 253         int err;
 254
 255         if (snd_BUG_ON(!ncontrol || !ncontrol->info))
 256                 return NULL;
 257
 258         count = ncontrol->count;
 259         if (count == 0)
 260                 count = 1;
 261
 262         access = ncontrol->access;
 263         if (access == 0)
 264                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
 265         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
 266                    SNDRV_CTL_ELEM_ACCESS_VOLATILE |
 267                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
 268                    SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
 269                    SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND |
 270                    SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK);
 271
 272         err = snd_ctl_new(&kctl, count, access, NULL);
 273         if (err < 0)
 274                 return NULL;
 275
 276         /* The 'numid' member is decided when calling snd_ctl_add(). */
 277         kctl->id.iface = ncontrol->iface;
 278         kctl->id.device = ncontrol->device;
 279         kctl->id.subdevice = ncontrol->subdevice;
 280         if (ncontrol->name) {
 281                 strlcpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name));
 282                 if (strcmp(ncontrol->name, kctl->id.name) != 0)
 283                         pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
 284                                 ncontrol->name, kctl->id.name);
 285         }
 286         kctl->id.index = ncontrol->index;
 287
 288         kctl->info = ncontrol->info;
 289         kctl->get = ncontrol->get;
 290         kctl->put = ncontrol->put;
 291         kctl->tlv.p = ncontrol->tlv.p;
 292
 293         kctl->private_value = ncontrol->private_value;
 294         kctl->private_data = private_data;
 295
 296         return kctl;
 297 }
 298 EXPORT_SYMBOL(snd_ctl_new1);
 299
 300 /**
 301  * snd_ctl_free_one - release the control instance
 302  * @kcontrol: the control instance
 303  *
 304  * Releases the control instance created via snd_ctl_new()
 305  * or snd_ctl_new1().
 306  * Don't call this after the control was added to the card.
 307  */
 308 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
 309 {
 310         if (kcontrol) {
 311                 if (kcontrol->private_free)
 312                         kcontrol->private_free(kcontrol);
 313                 kfree(kcontrol);
 314         }
 315 }
 316 EXPORT_SYMBOL(snd_ctl_free_one);
 317
 318 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
 319                                           unsigned int count)
 320 {
 321         struct snd_kcontrol *kctl;
 322
 323         /* Make sure that the ids assigned to the control do not wrap around */
 324         if (card->last_numid >= UINT_MAX - count)
 325                 card->last_numid = 0;
 326
 327         list_for_each_entry(kctl, &card->controls, list) {
 328                 if (kctl->id.numid < card->last_numid + 1 + count &&
 329                     kctl->id.numid + kctl->count > card->last_numid + 1) {
 330                         card->last_numid = kctl->id.numid + kctl->count - 1;
 331                         return true;
 332                 }
 333         }
 334         return false;
 335 }
 336
 337 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 338 {
 339         unsigned int iter = 100000;
 340
 341         while (snd_ctl_remove_numid_conflict(card, count)) {
 342                 if (--iter == 0) {
 343                         /* this situation is very unlikely */
 344                         dev_err(card->dev, "unable to allocate new control numid\n");
 345                         return -ENOMEM;
 346                 }
 347         }
 348         return 0;
 349 }
 350
 351 /**
 352  * snd_ctl_add - add the control instance to the card
 353  * @card: the card instance
 354  * @kcontrol: the control instance to add
 355  *
 356  * Adds the control instance created via snd_ctl_new() or
 357  * snd_ctl_new1() to the given card. Assigns also an unique
 358  * numid used for fast search.
 359  *
 360  * It frees automatically the control which cannot be added.
 361  *
 362  * Return: Zero if successful, or a negative error code on failure.
 363  *
 364  */
 365 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 366 {
 367         struct snd_ctl_elem_id id;
 368         unsigned int idx;
 369         unsigned int count;
 370         int err = -EINVAL;
 371
 372         if (! kcontrol)
 373                 return err;
 374         if (snd_BUG_ON(!card || !kcontrol->info))
 375                 goto error;
 376         id = kcontrol->id;
 377         if (id.index > UINT_MAX - kcontrol->count)
 378                 goto error;
 379
 380         down_write(&card->controls_rwsem);
 381         if (snd_ctl_find_id(card, &id)) {
 382                 up_write(&card->controls_rwsem);
 383                 dev_err(card->dev, "control %i:%i:%i:%s:%i is already present\n",
 384                                         id.iface,
 385                                         id.device,
 386                                         id.subdevice,
 387                                         id.name,
 388                                         id.index);
 389                 err = -EBUSY;
 390                 goto error;
 391         }
 392         if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 393                 up_write(&card->controls_rwsem);
 394                 err = -ENOMEM;
 395                 goto error;
 396         }
 397         list_add_tail(&kcontrol->list, &card->controls);
 398         card->controls_count += kcontrol->count;
 399         kcontrol->id.numid = card->last_numid + 1;
 400         card->last_numid += kcontrol->count;
 401         id = kcontrol->id;
 402         count = kcontrol->count;
 403         up_write(&card->controls_rwsem);
 404         for (idx = 0; idx < count; idx++, id.index++, id.numid++)
 405                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 406         return 0;
 407
 408  error:
 409         snd_ctl_free_one(kcontrol);
 410         return err;
 411 }
 412 EXPORT_SYMBOL(snd_ctl_add);
 413
 414 /**
 415  * snd_ctl_replace - replace the control instance of the card
 416  * @card: the card instance
 417  * @kcontrol: the control instance to replace
 418  * @add_on_replace: add the control if not already added
 419  *
 420  * Replaces the given control.  If the given control does not exist
 421  * and the add_on_replace flag is set, the control is added.  If the
 422  * control exists, it is destroyed first.
 423  *
 424  * It frees automatically the control which cannot be added or replaced.
 425  *
 426  * Return: Zero if successful, or a negative error code on failure.
 427  */
 428 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
 429                     bool add_on_replace)
 430 {
 431         struct snd_ctl_elem_id id;
 432         unsigned int count;
 433         unsigned int idx;
 434         struct snd_kcontrol *old;
 435         int ret;
 436
 437         if (!kcontrol)
 438                 return -EINVAL;
 439         if (snd_BUG_ON(!card || !kcontrol->info)) {
 440                 ret = -EINVAL;
 441                 goto error;
 442         }
 443         id = kcontrol->id;
 444         down_write(&card->controls_rwsem);
 445         old = snd_ctl_find_id(card, &id);
 446         if (!old) {
 447                 if (add_on_replace)
 448                         goto add;
 449                 up_write(&card->controls_rwsem);
 450                 ret = -EINVAL;
 451                 goto error;
 452         }
 453         ret = snd_ctl_remove(card, old);
 454         if (ret < 0) {
 455                 up_write(&card->controls_rwsem);
 456                 goto error;
 457         }
 458 add:
 459         if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 460                 up_write(&card->controls_rwsem);
 461                 ret = -ENOMEM;
 462                 goto error;
 463         }
 464         list_add_tail(&kcontrol->list, &card->controls);
 465         card->controls_count += kcontrol->count;
 466         kcontrol->id.numid = card->last_numid + 1;
 467         card->last_numid += kcontrol->count;
 468         id = kcontrol->id;
 469         count = kcontrol->count;
 470         up_write(&card->controls_rwsem);
 471         for (idx = 0; idx < count; idx++, id.index++, id.numid++)
 472                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 473         return 0;
 474
 475 error:
 476         snd_ctl_free_one(kcontrol);
 477         return ret;
 478 }
 479 EXPORT_SYMBOL(snd_ctl_replace);
 480
 481 /**
 482  * snd_ctl_remove - remove the control from the card and release it
 483  * @card: the card instance
 484  * @kcontrol: the control instance to remove
 485  *
 486  * Removes the control from the card and then releases the instance.
 487  * You don't need to call snd_ctl_free_one(). You must be in
 488  * the write lock - down_write(&card->controls_rwsem).
 489  *
 490  * Return: 0 if successful, or a negative error code on failure.
 491  */
 492 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 493 {
 494         struct snd_ctl_elem_id id;
 495         unsigned int idx;
 496
 497         if (snd_BUG_ON(!card || !kcontrol))
 498                 return -EINVAL;
 499         list_del(&kcontrol->list);
 500         card->controls_count -= kcontrol->count;
 501         id = kcontrol->id;
 502         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 503                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
 504         snd_ctl_free_one(kcontrol);
 505         return 0;
 506 }
 507 EXPORT_SYMBOL(snd_ctl_remove);
 508
 509 /**
 510  * snd_ctl_remove_id - remove the control of the given id and release it
 511  * @card: the card instance
 512  * @id: the control id to remove
 513  *
 514  * Finds the control instance with the given id, removes it from the
 515  * card list and releases it.
 516  *
 517  * Return: 0 if successful, or a negative error code on failure.
 518  */
 519 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 520 {
 521         struct snd_kcontrol *kctl;
 522         int ret;
 523
 524         down_write(&card->controls_rwsem);
 525         kctl = snd_ctl_find_id(card, id);
 526         if (kctl == NULL) {
 527                 up_write(&card->controls_rwsem);
 528                 return -ENOENT;
 529         }
 530         ret = snd_ctl_remove(card, kctl);
 531         up_write(&card->controls_rwsem);
 532         return ret;
 533 }
 534 EXPORT_SYMBOL(snd_ctl_remove_id);
 535
 536 /**
 537  * snd_ctl_remove_user_ctl - remove and release the unlocked user control
 538  * @file: active control handle
 539  * @id: the control id to remove
 540  *
 541  * Finds the control instance with the given id, removes it from the
 542  * card list and releases it.
 543  *
 544  * Return: 0 if successful, or a negative error code on failure.
 545  */
 546 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
 547                                    struct snd_ctl_elem_id *id)
 548 {
 549         struct snd_card *card = file->card;
 550         struct snd_kcontrol *kctl;
 551         int idx, ret;
 552
 553         down_write(&card->controls_rwsem);
 554         kctl = snd_ctl_find_id(card, id);
 555         if (kctl == NULL) {
 556                 ret = -ENOENT;
 557                 goto error;
 558         }
 559         if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
 560                 ret = -EINVAL;
 561                 goto error;
 562         }
 563         for (idx = 0; idx < kctl->count; idx++)
 564                 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
 565                         ret = -EBUSY;
 566                         goto error;
 567                 }
 568         ret = snd_ctl_remove(card, kctl);
 569         if (ret < 0)
 570                 goto error;
 571         card->user_ctl_count--;
 572 error:
 573         up_write(&card->controls_rwsem);
 574         return ret;
 575 }
 576
 577 /**
 578  * snd_ctl_activate_id - activate/inactivate the control of the given id
 579  * @card: the card instance
 580  * @id: the control id to activate/inactivate
 581  * @active: non-zero to activate
 582  *
 583  * Finds the control instance with the given id, and activate or
 584  * inactivate the control together with notification, if changed.
 585  * The given ID data is filled with full information.
 586  *
 587  * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
 588  */
 589 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
 590                         int active)
 591 {
 592         struct snd_kcontrol *kctl;
 593         struct snd_kcontrol_volatile *vd;
 594         unsigned int index_offset;
 595         int ret;
 596
 597         down_write(&card->controls_rwsem);
 598         kctl = snd_ctl_find_id(card, id);
 599         if (kctl == NULL) {
 600                 ret = -ENOENT;
 601                 goto unlock;
 602         }
 603         index_offset = snd_ctl_get_ioff(kctl, id);
 604         vd = &kctl->vd[index_offset];
 605         ret = 0;
 606         if (active) {
 607                 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
 608                         goto unlock;
 609                 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 610         } else {
 611                 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
 612                         goto unlock;
 613                 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 614         }
 615         snd_ctl_build_ioff(id, kctl, index_offset);
 616         ret = 1;
 617  unlock:
 618         up_write(&card->controls_rwsem);
 619         if (ret > 0)
 620                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
 621         return ret;
 622 }
 623 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
 624
 625 /**
 626  * snd_ctl_rename_id - replace the id of a control on the card
 627  * @card: the card instance
 628  * @src_id: the old id
 629  * @dst_id: the new id
 630  *
 631  * Finds the control with the old id from the card, and replaces the
 632  * id with the new one.
 633  *
 634  * Return: Zero if successful, or a negative error code on failure.
 635  */
 636 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 637                       struct snd_ctl_elem_id *dst_id)
 638 {
 639         struct snd_kcontrol *kctl;
 640
 641         down_write(&card->controls_rwsem);
 642         kctl = snd_ctl_find_id(card, src_id);
 643         if (kctl == NULL) {
 644                 up_write(&card->controls_rwsem);
 645                 return -ENOENT;
 646         }
 647         kctl->id = *dst_id;
 648         kctl->id.numid = card->last_numid + 1;
 649         card->last_numid += kctl->count;
 650         up_write(&card->controls_rwsem);
 651         return 0;
 652 }
 653 EXPORT_SYMBOL(snd_ctl_rename_id);
 654
 655 /**
 656  * snd_ctl_find_numid - find the control instance with the given number-id
 657  * @card: the card instance
 658  * @numid: the number-id to search
 659  *
 660  * Finds the control instance with the given number-id from the card.
 661  *
 662  * The caller must down card->controls_rwsem before calling this function
 663  * (if the race condition can happen).
 664  *
 665  * Return: The pointer of the instance if found, or %NULL if not.
 666  *
 667  */
 668 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 669 {
 670         struct snd_kcontrol *kctl;
 671
 672         if (snd_BUG_ON(!card || !numid))
 673                 return NULL;
 674         list_for_each_entry(kctl, &card->controls, list) {
 675                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 676                         return kctl;
 677         }
 678         return NULL;
 679 }
 680 EXPORT_SYMBOL(snd_ctl_find_numid);
 681
 682 /**
 683  * snd_ctl_find_id - find the control instance with the given id
 684  * @card: the card instance
 685  * @id: the id to search
 686  *
 687  * Finds the control instance with the given id from the card.
 688  *
 689  * The caller must down card->controls_rwsem before calling this function
 690  * (if the race condition can happen).
 691  *
 692  * Return: The pointer of the instance if found, or %NULL if not.
 693  *
 694  */
 695 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 696                                      struct snd_ctl_elem_id *id)
 697 {
 698         struct snd_kcontrol *kctl;
 699
 700         if (snd_BUG_ON(!card || !id))
 701                 return NULL;
 702         if (id->numid != 0)
 703                 return snd_ctl_find_numid(card, id->numid);
 704         list_for_each_entry(kctl, &card->controls, list) {
 705                 if (kctl->id.iface != id->iface)
 706                         continue;
 707                 if (kctl->id.device != id->device)
 708                         continue;
 709                 if (kctl->id.subdevice != id->subdevice)
 710                         continue;
 711                 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
 712                         continue;
 713                 if (kctl->id.index > id->index)
 714                         continue;
 715                 if (kctl->id.index + kctl->count <= id->index)
 716                         continue;
 717                 return kctl;
 718         }
 719         return NULL;
 720 }
 721 EXPORT_SYMBOL(snd_ctl_find_id);
 722
 723 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 724                              unsigned int cmd, void __user *arg)
 725 {
 726         struct snd_ctl_card_info *info;
 727
 728         info = kzalloc(sizeof(*info), GFP_KERNEL);
 729         if (! info)
 730                 return -ENOMEM;
 731         down_read(&snd_ioctl_rwsem);
 732         info->card = card->number;
 733         strlcpy(info->id, card->id, sizeof(info->id));
 734         strlcpy(info->driver, card->driver, sizeof(info->driver));
 735         strlcpy(info->name, card->shortname, sizeof(info->name));
 736         strlcpy(info->longname, card->longname, sizeof(info->longname));
 737         strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
 738         strlcpy(info->components, card->components, sizeof(info->components));
 739         up_read(&snd_ioctl_rwsem);
 740         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 741                 kfree(info);
 742                 return -EFAULT;
 743         }
 744         kfree(info);
 745         return 0;
 746 }
 747
 748 static int snd_ctl_elem_list(struct snd_card *card,
 749                              struct snd_ctl_elem_list __user *_list)
 750 {
 751         struct snd_ctl_elem_list list;
 752         struct snd_kcontrol *kctl;
 753         struct snd_ctl_elem_id id;
 754         unsigned int offset, space, jidx;
 755         int err = 0;
 756
 757         if (copy_from_user(&list, _list, sizeof(list)))
 758                 return -EFAULT;
 759         offset = list.offset;
 760         space = list.space;
 761
 762         down_read(&card->controls_rwsem);
 763         list.count = card->controls_count;
 764         list.used = 0;
 765         if (space > 0) {
 766                 list_for_each_entry(kctl, &card->controls, list) {
 767                         if (offset >= kctl->count) {
 768                                 offset -= kctl->count;
 769                                 continue;
 770                         }
 771                         for (jidx = offset; jidx < kctl->count; jidx++) {
 772                                 snd_ctl_build_ioff(&id, kctl, jidx);
 773                                 if (copy_to_user(list.pids + list.used, &id,
 774                                                  sizeof(id))) {
 775                                         err = -EFAULT;
 776                                         goto out;
 777                                 }
 778                                 list.used++;
 779                                 if (!--space)
 780                                         goto out;
 781                         }
 782                         offset = 0;
 783                 }
 784         }
 785  out:
 786         up_read(&card->controls_rwsem);
 787         if (!err && copy_to_user(_list, &list, sizeof(list)))
 788                 err = -EFAULT;
 789         return err;
 790 }
 791
 792 static bool validate_element_member_dimension(struct snd_ctl_elem_info *info)
 793 {
 794         unsigned int members;
 795         unsigned int i;
 796
 797         if (info->dimen.d[0] == 0)
 798                 return true;
 799
 800         members = 1;
 801         for (i = 0; i < ARRAY_SIZE(info->dimen.d); ++i) {
 802                 if (info->dimen.d[i] == 0)
 803                         break;
 804                 members *= info->dimen.d[i];
 805
 806                 /*
 807                  * info->count should be validated in advance, to guarantee
 808                  * calculation soundness.
 809                  */
 810                 if (members > info->count)
 811                         return false;
 812         }
 813
 814         for (++i; i < ARRAY_SIZE(info->dimen.d); ++i) {
 815                 if (info->dimen.d[i] > 0)
 816                         return false;
 817         }
 818
 819         return members == info->count;
 820 }
 821
 822 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 823                              struct snd_ctl_elem_info *info)
 824 {
 825         struct snd_card *card = ctl->card;
 826         struct snd_kcontrol *kctl;
 827         struct snd_kcontrol_volatile *vd;
 828         unsigned int index_offset;
 829         int result;
 830
 831         down_read(&card->controls_rwsem);
 832         kctl = snd_ctl_find_id(card, &info->id);
 833         if (kctl == NULL) {
 834                 up_read(&card->controls_rwsem);
 835                 return -ENOENT;
 836         }
 837 #ifdef CONFIG_SND_DEBUG
 838         info->access = 0;
 839 #endif
 840         result = kctl->info(kctl, info);
 841         if (result >= 0) {
 842                 snd_BUG_ON(info->access);
 843                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
 844                 vd = &kctl->vd[index_offset];
 845                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
 846                 info->access = vd->access;
 847                 if (vd->owner) {
 848                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
 849                         if (vd->owner == ctl)
 850                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
 851                         info->owner = pid_vnr(vd->owner->pid);
 852                 } else {
 853                         info->owner = -1;
 854                 }
 855         }
 856         up_read(&card->controls_rwsem);
 857         return result;
 858 }
 859
 860 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
 861                                   struct snd_ctl_elem_info __user *_info)
 862 {
 863         struct snd_ctl_elem_info info;
 864         int result;
 865
 866         if (copy_from_user(&info, _info, sizeof(info)))
 867                 return -EFAULT;
 868         result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
 869         if (result < 0)
 870                 return result;
 871         result = snd_ctl_elem_info(ctl, &info);
 872         if (result < 0)
 873                 return result;
 874         if (copy_to_user(_info, &info, sizeof(info)))
 875                 return -EFAULT;
 876         return result;
 877 }
 878
 879 static int snd_ctl_elem_read(struct snd_card *card,
 880                              struct snd_ctl_elem_value *control)
 881 {
 882         struct snd_kcontrol *kctl;
 883         struct snd_kcontrol_volatile *vd;
 884         unsigned int index_offset;
 885
 886         kctl = snd_ctl_find_id(card, &control->id);
 887         if (kctl == NULL)
 888                 return -ENOENT;
 889
 890         index_offset = snd_ctl_get_ioff(kctl, &control->id);
 891         vd = &kctl->vd[index_offset];
 892         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) && kctl->get == NULL)
 893                 return -EPERM;
 894
 895         snd_ctl_build_ioff(&control->id, kctl, index_offset);
 896         return kctl->get(kctl, control);
 897 }
 898
 899 static int snd_ctl_elem_read_user(struct snd_card *card,
 900                                   struct snd_ctl_elem_value __user *_control)
 901 {
 902         struct snd_ctl_elem_value *control;
 903         int result;
 904
 905         control = memdup_user(_control, sizeof(*control));
 906         if (IS_ERR(control))
 907                 return PTR_ERR(control);
 908
 909         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 910         if (result < 0)
 911                 goto error;
 912
 913         down_read(&card->controls_rwsem);
 914         result = snd_ctl_elem_read(card, control);
 915         up_read(&card->controls_rwsem);
 916         if (result < 0)
 917                 goto error;
 918
 919         if (copy_to_user(_control, control, sizeof(*control)))
 920                 result = -EFAULT;
 921  error:
 922         kfree(control);
 923         return result;
 924 }
 925
 926 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
 927                               struct snd_ctl_elem_value *control)
 928 {
 929         struct snd_kcontrol *kctl;
 930         struct snd_kcontrol_volatile *vd;
 931         unsigned int index_offset;
 932         int result;
 933
 934         kctl = snd_ctl_find_id(card, &control->id);
 935         if (kctl == NULL)
 936                 return -ENOENT;
 937
 938         index_offset = snd_ctl_get_ioff(kctl, &control->id);
 939         vd = &kctl->vd[index_offset];
 940         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) || kctl->put == NULL ||
 941             (file && vd->owner && vd->owner != file)) {
 942                 return -EPERM;
 943         }
 944
 945         snd_ctl_build_ioff(&control->id, kctl, index_offset);
 946         result = kctl->put(kctl, control);
 947         if (result < 0)
 948                 return result;
 949
 950         if (result > 0) {
 951                 struct snd_ctl_elem_id id = control->id;
 952                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &id);
 953         }
 954
 955         return 0;
 956 }
 957
 958 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
 959                                    struct snd_ctl_elem_value __user *_control)
 960 {
 961         struct snd_ctl_elem_value *control;
 962         struct snd_card *card;
 963         int result;
 964
 965         control = memdup_user(_control, sizeof(*control));
 966         if (IS_ERR(control))
 967                 return PTR_ERR(control);
 968
 969         card = file->card;
 970         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 971         if (result < 0)
 972                 goto error;
 973
 974         down_write(&card->controls_rwsem);
 975         result = snd_ctl_elem_write(card, file, control);
 976         up_write(&card->controls_rwsem);
 977         if (result < 0)
 978                 goto error;
 979
 980         if (copy_to_user(_control, control, sizeof(*control)))
 981                 result = -EFAULT;
 982  error:
 983         kfree(control);
 984         return result;
 985 }
 986
 987 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
 988                              struct snd_ctl_elem_id __user *_id)
 989 {
 990         struct snd_card *card = file->card;
 991         struct snd_ctl_elem_id id;
 992         struct snd_kcontrol *kctl;
 993         struct snd_kcontrol_volatile *vd;
 994         int result;
 995
 996         if (copy_from_user(&id, _id, sizeof(id)))
 997                 return -EFAULT;
 998         down_write(&card->controls_rwsem);
 999         kctl = snd_ctl_find_id(card, &id);
1000         if (kctl == NULL) {
1001                 result = -ENOENT;
1002         } else {
1003                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1004                 if (vd->owner != NULL)
1005                         result = -EBUSY;
1006                 else {
1007                         vd->owner = file;
1008                         result = 0;
1009                 }
1010         }
1011         up_write(&card->controls_rwsem);
1012         return result;
1013 }
1014
1015 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
1016                                struct snd_ctl_elem_id __user *_id)
1017 {
1018         struct snd_card *card = file->card;
1019         struct snd_ctl_elem_id id;
1020         struct snd_kcontrol *kctl;
1021         struct snd_kcontrol_volatile *vd;
1022         int result;
1023
1024         if (copy_from_user(&id, _id, sizeof(id)))
1025                 return -EFAULT;
1026         down_write(&card->controls_rwsem);
1027         kctl = snd_ctl_find_id(card, &id);
1028         if (kctl == NULL) {
1029                 result = -ENOENT;
1030         } else {
1031                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1032                 if (vd->owner == NULL)
1033                         result = -EINVAL;
1034                 else if (vd->owner != file)
1035                         result = -EPERM;
1036                 else {
1037                         vd->owner = NULL;
1038                         result = 0;
1039                 }
1040         }
1041         up_write(&card->controls_rwsem);
1042         return result;
1043 }
1044
1045 struct user_element {
1046         struct snd_ctl_elem_info info;
1047         struct snd_card *card;
1048         char *elem_data;                /* element data */
1049         unsigned long elem_data_size;   /* size of element data in bytes */
1050         void *tlv_data;                 /* TLV data */
1051         unsigned long tlv_data_size;    /* TLV data size */
1052         void *priv_data;                /* private data (like strings for enumerated type) */
1053 };
1054
1055 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1056                                   struct snd_ctl_elem_info *uinfo)
1057 {
1058         struct user_element *ue = kcontrol->private_data;
1059         unsigned int offset;
1060
1061         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1062         *uinfo = ue->info;
1063         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1064
1065         return 0;
1066 }
1067
1068 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1069                                        struct snd_ctl_elem_info *uinfo)
1070 {
1071         struct user_element *ue = kcontrol->private_data;
1072         const char *names;
1073         unsigned int item;
1074         unsigned int offset;
1075
1076         item = uinfo->value.enumerated.item;
1077
1078         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1079         *uinfo = ue->info;
1080         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1081
1082         item = min(item, uinfo->value.enumerated.items - 1);
1083         uinfo->value.enumerated.item = item;
1084
1085         names = ue->priv_data;
1086         for (; item > 0; --item)
1087                 names += strlen(names) + 1;
1088         strcpy(uinfo->value.enumerated.name, names);
1089
1090         return 0;
1091 }
1092
1093 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1094                                  struct snd_ctl_elem_value *ucontrol)
1095 {
1096         struct user_element *ue = kcontrol->private_data;
1097         unsigned int size = ue->elem_data_size;
1098         char *src = ue->elem_data +
1099                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1100
1101         memcpy(&ucontrol->value, src, size);
1102         return 0;
1103 }
1104
1105 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1106                                  struct snd_ctl_elem_value *ucontrol)
1107 {
1108         int change;
1109         struct user_element *ue = kcontrol->private_data;
1110         unsigned int size = ue->elem_data_size;
1111         char *dst = ue->elem_data +
1112                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1113
1114         change = memcmp(&ucontrol->value, dst, size) != 0;
1115         if (change)
1116                 memcpy(dst, &ucontrol->value, size);
1117         return change;
1118 }
1119
1120 static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1121                             unsigned int size)
1122 {
1123         struct user_element *ue = kctl->private_data;
1124         unsigned int *container;
1125         struct snd_ctl_elem_id id;
1126         unsigned int mask = 0;
1127         int i;
1128         int change;
1129
1130         if (size > 1024 * 128)  /* sane value */
1131                 return -EINVAL;
1132
1133         container = vmemdup_user(buf, size);
1134         if (IS_ERR(container))
1135                 return PTR_ERR(container);
1136
1137         change = ue->tlv_data_size != size;
1138         if (!change)
1139                 change = memcmp(ue->tlv_data, container, size) != 0;
1140         if (!change) {
1141                 kvfree(container);
1142                 return 0;
1143         }
1144
1145         if (ue->tlv_data == NULL) {
1146                 /* Now TLV data is available. */
1147                 for (i = 0; i < kctl->count; ++i)
1148                         kctl->vd[i].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
1149                 mask = SNDRV_CTL_EVENT_MASK_INFO;
1150         }
1151
1152         kvfree(ue->tlv_data);
1153         ue->tlv_data = container;
1154         ue->tlv_data_size = size;
1155
1156         mask |= SNDRV_CTL_EVENT_MASK_TLV;
1157         for (i = 0; i < kctl->count; ++i) {
1158                 snd_ctl_build_ioff(&id, kctl, i);
1159                 snd_ctl_notify(ue->card, mask, &id);
1160         }
1161
1162         return change;
1163 }
1164
1165 static int read_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1166                          unsigned int size)
1167 {
1168         struct user_element *ue = kctl->private_data;
1169
1170         if (ue->tlv_data_size == 0 || ue->tlv_data == NULL)
1171                 return -ENXIO;
1172
1173         if (size < ue->tlv_data_size)
1174                 return -ENOSPC;
1175
1176         if (copy_to_user(buf, ue->tlv_data, ue->tlv_data_size))
1177                 return -EFAULT;
1178
1179         return 0;
1180 }
1181
1182 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kctl, int op_flag,
1183                                  unsigned int size, unsigned int __user *buf)
1184 {
1185         if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
1186                 return replace_user_tlv(kctl, buf, size);
1187         else
1188                 return read_user_tlv(kctl, buf, size);
1189 }
1190
1191 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1192 {
1193         char *names, *p;
1194         size_t buf_len, name_len;
1195         unsigned int i;
1196         const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1197
1198         if (ue->info.value.enumerated.names_length > 64 * 1024)
1199                 return -EINVAL;
1200
1201         names = vmemdup_user((const void __user *)user_ptrval,
1202                 ue->info.value.enumerated.names_length);
1203         if (IS_ERR(names))
1204                 return PTR_ERR(names);
1205
1206         /* check that there are enough valid names */
1207         buf_len = ue->info.value.enumerated.names_length;
1208         p = names;
1209         for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1210                 name_len = strnlen(p, buf_len);
1211                 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1212                         kvfree(names);
1213                         return -EINVAL;
1214                 }
1215                 p += name_len + 1;
1216                 buf_len -= name_len + 1;
1217         }
1218
1219         ue->priv_data = names;
1220         ue->info.value.enumerated.names_ptr = 0;
1221
1222         return 0;
1223 }
1224
1225 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1226 {
1227         struct user_element *ue = kcontrol->private_data;
1228
1229         kvfree(ue->tlv_data);
1230         kvfree(ue->priv_data);
1231         kfree(ue);
1232 }
1233
1234 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1235                             struct snd_ctl_elem_info *info, int replace)
1236 {
1237         /* The capacity of struct snd_ctl_elem_value.value.*/
1238         static const unsigned int value_sizes[] = {
1239                 [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = sizeof(long),
1240                 [SNDRV_CTL_ELEM_TYPE_INTEGER]   = sizeof(long),
1241                 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),
1242                 [SNDRV_CTL_ELEM_TYPE_BYTES]     = sizeof(unsigned char),
1243                 [SNDRV_CTL_ELEM_TYPE_IEC958]    = sizeof(struct snd_aes_iec958),
1244                 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),
1245         };
1246         static const unsigned int max_value_counts[] = {
1247                 [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = 128,
1248                 [SNDRV_CTL_ELEM_TYPE_INTEGER]   = 128,
1249                 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
1250                 [SNDRV_CTL_ELEM_TYPE_BYTES]     = 512,
1251                 [SNDRV_CTL_ELEM_TYPE_IEC958]    = 1,
1252                 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
1253         };
1254         struct snd_card *card = file->card;
1255         struct snd_kcontrol *kctl;
1256         unsigned int count;
1257         unsigned int access;
1258         long private_size;
1259         struct user_element *ue;
1260         unsigned int offset;
1261         int err;
1262
1263         if (!*info->id.name)
1264                 return -EINVAL;
1265         if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
1266                 return -EINVAL;
1267
1268         /* Delete a control to replace them if needed. */
1269         if (replace) {
1270                 info->id.numid = 0;
1271                 err = snd_ctl_remove_user_ctl(file, &info->id);
1272                 if (err)
1273                         return err;
1274         }
1275
1276         /*
1277          * The number of userspace controls are counted control by control,
1278          * not element by element.
1279          */
1280         if (card->user_ctl_count + 1 > MAX_USER_CONTROLS)
1281                 return -ENOMEM;
1282
1283         /* Check the number of elements for this userspace control. */
1284         count = info->owner;
1285         if (count == 0)
1286                 count = 1;
1287
1288         /* Arrange access permissions if needed. */
1289         access = info->access;
1290         if (access == 0)
1291                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
1292         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
1293                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
1294                    SNDRV_CTL_ELEM_ACCESS_TLV_WRITE);
1295
1296         /* In initial state, nothing is available as TLV container. */
1297         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1298                 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1299         access |= SNDRV_CTL_ELEM_ACCESS_USER;
1300
1301         /*
1302          * Check information and calculate the size of data specific to
1303          * this userspace control.
1304          */
1305         if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
1306             info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64)
1307                 return -EINVAL;
1308         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
1309             info->value.enumerated.items == 0)
1310                 return -EINVAL;
1311         if (info->count < 1 ||
1312             info->count > max_value_counts[info->type])
1313                 return -EINVAL;
1314         if (!validate_element_member_dimension(info))
1315                 return -EINVAL;
1316         private_size = value_sizes[info->type] * info->count;
1317
1318         /*
1319          * Keep memory object for this userspace control. After passing this
1320          * code block, the instance should be freed by snd_ctl_free_one().
1321          *
1322          * Note that these elements in this control are locked.
1323          */
1324         err = snd_ctl_new(&kctl, count, access, file);
1325         if (err < 0)
1326                 return err;
1327         memcpy(&kctl->id, &info->id, sizeof(kctl->id));
1328         kctl->private_data = kzalloc(sizeof(struct user_element) + private_size * count,
1329                                      GFP_KERNEL);
1330         if (kctl->private_data == NULL) {
1331                 kfree(kctl);
1332                 return -ENOMEM;
1333         }
1334         kctl->private_free = snd_ctl_elem_user_free;
1335
1336         /* Set private data for this userspace control. */
1337         ue = (struct user_element *)kctl->private_data;
1338         ue->card = card;
1339         ue->info = *info;
1340         ue->info.access = 0;
1341         ue->elem_data = (char *)ue + sizeof(*ue);
1342         ue->elem_data_size = private_size;
1343         if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1344                 err = snd_ctl_elem_init_enum_names(ue);
1345                 if (err < 0) {
1346                         snd_ctl_free_one(kctl);
1347                         return err;
1348                 }
1349         }
1350
1351         /* Set callback functions. */
1352         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1353                 kctl->info = snd_ctl_elem_user_enum_info;
1354         else
1355                 kctl->info = snd_ctl_elem_user_info;
1356         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1357                 kctl->get = snd_ctl_elem_user_get;
1358         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1359                 kctl->put = snd_ctl_elem_user_put;
1360         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1361                 kctl->tlv.c = snd_ctl_elem_user_tlv;
1362
1363         /* This function manage to free the instance on failure. */
1364         err = snd_ctl_add(card, kctl);
1365         if (err < 0)
1366                 return err;
1367         offset = snd_ctl_get_ioff(kctl, &info->id);
1368         snd_ctl_build_ioff(&info->id, kctl, offset);
1369         /*
1370          * Here we cannot fill any field for the number of elements added by
1371          * this operation because there're no specific fields. The usage of
1372          * 'owner' field for this purpose may cause any bugs to userspace
1373          * applications because the field originally means PID of a process
1374          * which locks the element.
1375          */
1376
1377         down_write(&card->controls_rwsem);
1378         card->user_ctl_count++;
1379         up_write(&card->controls_rwsem);
1380
1381         return 0;
1382 }
1383
1384 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1385                                  struct snd_ctl_elem_info __user *_info, int replace)
1386 {
1387         struct snd_ctl_elem_info info;
1388         int err;
1389
1390         if (copy_from_user(&info, _info, sizeof(info)))
1391                 return -EFAULT;
1392         err = snd_ctl_elem_add(file, &info, replace);
1393         if (err < 0)
1394                 return err;
1395         if (copy_to_user(_info, &info, sizeof(info))) {
1396                 snd_ctl_remove_user_ctl(file, &info.id);
1397                 return -EFAULT;
1398         }
1399
1400         return 0;
1401 }
1402
1403 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1404                                struct snd_ctl_elem_id __user *_id)
1405 {
1406         struct snd_ctl_elem_id id;
1407
1408         if (copy_from_user(&id, _id, sizeof(id)))
1409                 return -EFAULT;
1410         return snd_ctl_remove_user_ctl(file, &id);
1411 }
1412
1413 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1414 {
1415         int subscribe;
1416         if (get_user(subscribe, ptr))
1417                 return -EFAULT;
1418         if (subscribe < 0) {
1419                 subscribe = file->subscribed;
1420                 if (put_user(subscribe, ptr))
1421                         return -EFAULT;
1422                 return 0;
1423         }
1424         if (subscribe) {
1425                 file->subscribed = 1;
1426                 return 0;
1427         } else if (file->subscribed) {
1428                 snd_ctl_empty_read_queue(file);
1429                 file->subscribed = 0;
1430         }
1431         return 0;
1432 }
1433
1434 static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,
1435                             struct snd_kcontrol *kctl,
1436                             struct snd_ctl_elem_id *id,
1437                             unsigned int __user *buf, unsigned int size)
1438 {
1439         static const struct {
1440                 int op;
1441                 int perm;
1442         } pairs[] = {
1443                 {SNDRV_CTL_TLV_OP_READ,  SNDRV_CTL_ELEM_ACCESS_TLV_READ},
1444                 {SNDRV_CTL_TLV_OP_WRITE, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE},
1445                 {SNDRV_CTL_TLV_OP_CMD,   SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},
1446         };
1447         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1448         int i;
1449
1450         /* Check support of the request for this element. */
1451         for (i = 0; i < ARRAY_SIZE(pairs); ++i) {
1452                 if (op_flag == pairs[i].op && (vd->access & pairs[i].perm))
1453                         break;
1454         }
1455         if (i == ARRAY_SIZE(pairs))
1456                 return -ENXIO;
1457
1458         if (kctl->tlv.c == NULL)
1459                 return -ENXIO;
1460
1461         /* When locked, this is unavailable. */
1462         if (vd->owner != NULL && vd->owner != file)
1463                 return -EPERM;
1464
1465         return kctl->tlv.c(kctl, op_flag, size, buf);
1466 }
1467
1468 static int read_tlv_buf(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id,
1469                         unsigned int __user *buf, unsigned int size)
1470 {
1471         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1472         unsigned int len;
1473
1474         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ))
1475                 return -ENXIO;
1476
1477         if (kctl->tlv.p == NULL)
1478                 return -ENXIO;
1479
1480         len = sizeof(unsigned int) * 2 + kctl->tlv.p[1];
1481         if (size < len)
1482                 return -ENOMEM;
1483
1484         if (copy_to_user(buf, kctl->tlv.p, len))
1485                 return -EFAULT;
1486
1487         return 0;
1488 }
1489
1490 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1491                              struct snd_ctl_tlv __user *buf,
1492                              int op_flag)
1493 {
1494         struct snd_ctl_tlv header;
1495         unsigned int *container;
1496         unsigned int container_size;
1497         struct snd_kcontrol *kctl;
1498         struct snd_ctl_elem_id id;
1499         struct snd_kcontrol_volatile *vd;
1500
1501         if (copy_from_user(&header, buf, sizeof(header)))
1502                 return -EFAULT;
1503
1504         /* In design of control core, numerical ID starts at 1. */
1505         if (header.numid == 0)
1506                 return -EINVAL;
1507
1508         /* At least, container should include type and length fields.  */
1509         if (header.length < sizeof(unsigned int) * 2)
1510                 return -EINVAL;
1511         container_size = header.length;
1512         container = buf->tlv;
1513
1514         kctl = snd_ctl_find_numid(file->card, header.numid);
1515         if (kctl == NULL)
1516                 return -ENOENT;
1517
1518         /* Calculate index of the element in this set. */
1519         id = kctl->id;
1520         snd_ctl_build_ioff(&id, kctl, header.numid - id.numid);
1521         vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1522
1523         if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1524                 return call_tlv_handler(file, op_flag, kctl, &id, container,
1525                                         container_size);
1526         } else {
1527                 if (op_flag == SNDRV_CTL_TLV_OP_READ) {
1528                         return read_tlv_buf(kctl, &id, container,
1529                                             container_size);
1530                 }
1531         }
1532
1533         /* Not supported. */
1534         return -ENXIO;
1535 }
1536
1537 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1538 {
1539         struct snd_ctl_file *ctl;
1540         struct snd_card *card;
1541         struct snd_kctl_ioctl *p;
1542         void __user *argp = (void __user *)arg;
1543         int __user *ip = argp;
1544         int err;
1545
1546         ctl = file->private_data;
1547         card = ctl->card;
1548         if (snd_BUG_ON(!card))
1549                 return -ENXIO;
1550         switch (cmd) {
1551         case SNDRV_CTL_IOCTL_PVERSION:
1552                 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1553         case SNDRV_CTL_IOCTL_CARD_INFO:
1554                 return snd_ctl_card_info(card, ctl, cmd, argp);
1555         case SNDRV_CTL_IOCTL_ELEM_LIST:
1556                 return snd_ctl_elem_list(card, argp);
1557         case SNDRV_CTL_IOCTL_ELEM_INFO:
1558                 return snd_ctl_elem_info_user(ctl, argp);
1559         case SNDRV_CTL_IOCTL_ELEM_READ:
1560                 return snd_ctl_elem_read_user(card, argp);
1561         case SNDRV_CTL_IOCTL_ELEM_WRITE:
1562                 return snd_ctl_elem_write_user(ctl, argp);
1563         case SNDRV_CTL_IOCTL_ELEM_LOCK:
1564                 return snd_ctl_elem_lock(ctl, argp);
1565         case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1566                 return snd_ctl_elem_unlock(ctl, argp);
1567         case SNDRV_CTL_IOCTL_ELEM_ADD:
1568                 return snd_ctl_elem_add_user(ctl, argp, 0);
1569         case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1570                 return snd_ctl_elem_add_user(ctl, argp, 1);
1571         case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1572                 return snd_ctl_elem_remove(ctl, argp);
1573         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1574                 return snd_ctl_subscribe_events(ctl, ip);
1575         case SNDRV_CTL_IOCTL_TLV_READ:
1576                 down_read(&ctl->card->controls_rwsem);
1577                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
1578                 up_read(&ctl->card->controls_rwsem);
1579                 return err;
1580         case SNDRV_CTL_IOCTL_TLV_WRITE:
1581                 down_write(&ctl->card->controls_rwsem);
1582                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
1583                 up_write(&ctl->card->controls_rwsem);
1584                 return err;
1585         case SNDRV_CTL_IOCTL_TLV_COMMAND:
1586                 down_write(&ctl->card->controls_rwsem);
1587                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
1588                 up_write(&ctl->card->controls_rwsem);
1589                 return err;
1590         case SNDRV_CTL_IOCTL_POWER:
1591                 return -ENOPROTOOPT;
1592         case SNDRV_CTL_IOCTL_POWER_STATE:
1593 #ifdef CONFIG_PM
1594                 return put_user(card->power_state, ip) ? -EFAULT : 0;
1595 #else
1596                 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1597 #endif
1598         }
1599         down_read(&snd_ioctl_rwsem);
1600         list_for_each_entry(p, &snd_control_ioctls, list) {
1601                 err = p->fioctl(card, ctl, cmd, arg);
1602                 if (err != -ENOIOCTLCMD) {
1603                         up_read(&snd_ioctl_rwsem);
1604                         return err;
1605                 }
1606         }
1607         up_read(&snd_ioctl_rwsem);
1608         dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
1609         return -ENOTTY;
1610 }
1611
1612 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1613                             size_t count, loff_t * offset)
1614 {
1615         struct snd_ctl_file *ctl;
1616         int err = 0;
1617         ssize_t result = 0;
1618
1619         ctl = file->private_data;
1620         if (snd_BUG_ON(!ctl || !ctl->card))
1621                 return -ENXIO;
1622         if (!ctl->subscribed)
1623                 return -EBADFD;
1624         if (count < sizeof(struct snd_ctl_event))
1625                 return -EINVAL;
1626         spin_lock_irq(&ctl->read_lock);
1627         while (count >= sizeof(struct snd_ctl_event)) {
1628                 struct snd_ctl_event ev;
1629                 struct snd_kctl_event *kev;
1630                 while (list_empty(&ctl->events)) {
1631                         wait_queue_entry_t wait;
1632                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1633                                 err = -EAGAIN;
1634                                 goto __end_lock;
1635                         }
1636                         init_waitqueue_entry(&wait, current);
1637                         add_wait_queue(&ctl->change_sleep, &wait);
1638                         set_current_state(TASK_INTERRUPTIBLE);
1639                         spin_unlock_irq(&ctl->read_lock);
1640                         schedule();
1641                         remove_wait_queue(&ctl->change_sleep, &wait);
1642                         if (ctl->card->shutdown)
1643                                 return -ENODEV;
1644                         if (signal_pending(current))
1645                                 return -ERESTARTSYS;
1646                         spin_lock_irq(&ctl->read_lock);
1647                 }
1648                 kev = snd_kctl_event(ctl->events.next);
1649                 ev.type = SNDRV_CTL_EVENT_ELEM;
1650                 ev.data.elem.mask = kev->mask;
1651                 ev.data.elem.id = kev->id;
1652                 list_del(&kev->list);
1653                 spin_unlock_irq(&ctl->read_lock);
1654                 kfree(kev);
1655                 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1656                         err = -EFAULT;
1657                         goto __end;
1658                 }
1659                 spin_lock_irq(&ctl->read_lock);
1660                 buffer += sizeof(struct snd_ctl_event);
1661                 count -= sizeof(struct snd_ctl_event);
1662                 result += sizeof(struct snd_ctl_event);
1663         }
1664       __end_lock:
1665         spin_unlock_irq(&ctl->read_lock);
1666       __end:
1667         return result > 0 ? result : err;
1668 }
1669
1670 static __poll_t snd_ctl_poll(struct file *file, poll_table * wait)
1671 {
1672         __poll_t mask;
1673         struct snd_ctl_file *ctl;
1674
1675         ctl = file->private_data;
1676         if (!ctl->subscribed)
1677                 return 0;
1678         poll_wait(file, &ctl->change_sleep, wait);
1679
1680         mask = 0;
1681         if (!list_empty(&ctl->events))
1682                 mask |= POLLIN | POLLRDNORM;
1683
1684         return mask;
1685 }
1686
1687 /*
1688  * register the device-specific control-ioctls.
1689  * called from each device manager like pcm.c, hwdep.c, etc.
1690  */
1691 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1692 {
1693         struct snd_kctl_ioctl *pn;
1694
1695         pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1696         if (pn == NULL)
1697                 return -ENOMEM;
1698         pn->fioctl = fcn;
1699         down_write(&snd_ioctl_rwsem);
1700         list_add_tail(&pn->list, lists);
1701         up_write(&snd_ioctl_rwsem);
1702         return 0;
1703 }
1704
1705 /**
1706  * snd_ctl_register_ioctl - register the device-specific control-ioctls
1707  * @fcn: ioctl callback function
1708  *
1709  * called from each device manager like pcm.c, hwdep.c, etc.
1710  */
1711 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1712 {
1713         return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1714 }
1715 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1716
1717 #ifdef CONFIG_COMPAT
1718 /**
1719  * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
1720  * control-ioctls
1721  * @fcn: ioctl callback function
1722  */
1723 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1724 {
1725         return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1726 }
1727 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1728 #endif
1729
1730 /*
1731  * de-register the device-specific control-ioctls.
1732  */
1733 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1734                                      struct list_head *lists)
1735 {
1736         struct snd_kctl_ioctl *p;
1737
1738         if (snd_BUG_ON(!fcn))
1739                 return -EINVAL;
1740         down_write(&snd_ioctl_rwsem);
1741         list_for_each_entry(p, lists, list) {
1742                 if (p->fioctl == fcn) {
1743                         list_del(&p->list);
1744                         up_write(&snd_ioctl_rwsem);
1745                         kfree(p);
1746                         return 0;
1747                 }
1748         }
1749         up_write(&snd_ioctl_rwsem);
1750         snd_BUG();
1751         return -EINVAL;
1752 }
1753
1754 /**
1755  * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
1756  * @fcn: ioctl callback function to unregister
1757  */
1758 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1759 {
1760         return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1761 }
1762 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1763
1764 #ifdef CONFIG_COMPAT
1765 /**
1766  * snd_ctl_unregister_ioctl - de-register the device-specific compat 32bit
1767  * control-ioctls
1768  * @fcn: ioctl callback function to unregister
1769  */
1770 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1771 {
1772         return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1773 }
1774 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1775 #endif
1776
1777 static int snd_ctl_fasync(int fd, struct file * file, int on)
1778 {
1779         struct snd_ctl_file *ctl;
1780
1781         ctl = file->private_data;
1782         return fasync_helper(fd, file, on, &ctl->fasync);
1783 }
1784
1785 /* return the preferred subdevice number if already assigned;
1786  * otherwise return -1
1787  */
1788 int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
1789 {
1790         struct snd_ctl_file *kctl;
1791         int subdevice = -1;
1792
1793         read_lock(&card->ctl_files_rwlock);
1794         list_for_each_entry(kctl, &card->ctl_files, list) {
1795                 if (kctl->pid == task_pid(current)) {
1796                         subdevice = kctl->preferred_subdevice[type];
1797                         if (subdevice != -1)
1798                                 break;
1799                 }
1800         }
1801         read_unlock(&card->ctl_files_rwlock);
1802         return subdevice;
1803 }
1804 EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
1805
1806 /*
1807  * ioctl32 compat
1808  */
1809 #ifdef CONFIG_COMPAT
1810 #include "control_compat.c"
1811 #else
1812 #define snd_ctl_ioctl_compat    NULL
1813 #endif
1814
1815 /*
1816  *  INIT PART
1817  */
1818
1819 static const struct file_operations snd_ctl_f_ops =
1820 {
1821         .owner =        THIS_MODULE,
1822         .read =         snd_ctl_read,
1823         .open =         snd_ctl_open,
1824         .release =      snd_ctl_release,
1825         .llseek =       no_llseek,
1826         .poll =         snd_ctl_poll,
1827         .unlocked_ioctl =       snd_ctl_ioctl,
1828         .compat_ioctl = snd_ctl_ioctl_compat,
1829         .fasync =       snd_ctl_fasync,
1830 };
1831
1832 /*
1833  * registration of the control device
1834  */
1835 static int snd_ctl_dev_register(struct snd_device *device)
1836 {
1837         struct snd_card *card = device->device_data;
1838
1839         return snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
1840                                    &snd_ctl_f_ops, card, &card->ctl_dev);
1841 }
1842
1843 /*
1844  * disconnection of the control device
1845  */
1846 static int snd_ctl_dev_disconnect(struct snd_device *device)
1847 {
1848         struct snd_card *card = device->device_data;
1849         struct snd_ctl_file *ctl;
1850
1851         read_lock(&card->ctl_files_rwlock);
1852         list_for_each_entry(ctl, &card->ctl_files, list) {
1853                 wake_up(&ctl->change_sleep);
1854                 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1855         }
1856         read_unlock(&card->ctl_files_rwlock);
1857
1858         return snd_unregister_device(&card->ctl_dev);
1859 }
1860
1861 /*
1862  * free all controls
1863  */
1864 static int snd_ctl_dev_free(struct snd_device *device)
1865 {
1866         struct snd_card *card = device->device_data;
1867         struct snd_kcontrol *control;
1868
1869         down_write(&card->controls_rwsem);
1870         while (!list_empty(&card->controls)) {
1871                 control = snd_kcontrol(card->controls.next);
1872                 snd_ctl_remove(card, control);
1873         }
1874         up_write(&card->controls_rwsem);
1875         put_device(&card->ctl_dev);
1876         return 0;
1877 }
1878
1879 /*
1880  * create control core:
1881  * called from init.c
1882  */
1883 int snd_ctl_create(struct snd_card *card)
1884 {
1885         static struct snd_device_ops ops = {
1886                 .dev_free = snd_ctl_dev_free,
1887                 .dev_register = snd_ctl_dev_register,
1888                 .dev_disconnect = snd_ctl_dev_disconnect,
1889         };
1890         int err;
1891
1892         if (snd_BUG_ON(!card))
1893                 return -ENXIO;
1894         if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))
1895                 return -ENXIO;
1896
1897         snd_device_initialize(&card->ctl_dev, card);
1898         dev_set_name(&card->ctl_dev, "controlC%d", card->number);
1899
1900         err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1901         if (err < 0)
1902                 put_device(&card->ctl_dev);
1903         return err;
1904 }
1905
1906 /*
1907  * Frequently used control callbacks/helpers
1908  */
1909
1910 /**
1911  * snd_ctl_boolean_mono_info - Helper function for a standard boolean info
1912  * callback with a mono channel
1913  * @kcontrol: the kcontrol instance
1914  * @uinfo: info to store
1915  *
1916  * This is a function that can be used as info callback for a standard
1917  * boolean control with a single mono channel.
1918  */
1919 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
1920                               struct snd_ctl_elem_info *uinfo)
1921 {
1922         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1923         uinfo->count = 1;
1924         uinfo->value.integer.min = 0;
1925         uinfo->value.integer.max = 1;
1926         return 0;
1927 }
1928 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
1929
1930 /**
1931  * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
1932  * callback with stereo two channels
1933  * @kcontrol: the kcontrol instance
1934  * @uinfo: info to store
1935  *
1936  * This is a function that can be used as info callback for a standard
1937  * boolean control with stereo two channels.
1938  */
1939 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
1940                                 struct snd_ctl_elem_info *uinfo)
1941 {
1942         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1943         uinfo->count = 2;
1944         uinfo->value.integer.min = 0;
1945         uinfo->value.integer.max = 1;
1946         return 0;
1947 }
1948 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
1949
1950 /**
1951  * snd_ctl_enum_info - fills the info structure for an enumerated control
1952  * @info: the structure to be filled
1953  * @channels: the number of the control's channels; often one
1954  * @items: the number of control values; also the size of @names
1955  * @names: an array containing the names of all control values
1956  *
1957  * Sets all required fields in @info to their appropriate values.
1958  * If the control's accessibility is not the default (readable and writable),
1959  * the caller has to fill @info->access.
1960  *
1961  * Return: Zero.
1962  */
1963 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
1964                       unsigned int items, const char *const names[])
1965 {
1966         info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
1967         info->count = channels;
1968         info->value.enumerated.items = items;
1969         if (!items)
1970                 return 0;
1971         if (info->value.enumerated.item >= items)
1972                 info->value.enumerated.item = items - 1;
1973         WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),
1974              "ALSA: too long item name '%s'\n",
1975              names[info->value.enumerated.item]);
1976         strlcpy(info->value.enumerated.name,
1977                 names[info->value.enumerated.item],
1978                 sizeof(info->value.enumerated.name));
1979         return 0;
1980 }
1981 EXPORT_SYMBOL(snd_ctl_enum_info);