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