sound/core/control.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Routines for driver control interface
   4  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   5  */
   6
   7 #include <linux/threads.h>
   8 #include <linux/interrupt.h>
   9 #include <linux/module.h>
  10 #include <linux/slab.h>
  11 #include <linux/vmalloc.h>
  12 #include <linux/time.h>
  13 #include <linux/mm.h>
  14 #include <linux/math64.h>
  15 #include <linux/sched/signal.h>
  16 #include <sound/core.h>
  17 #include <sound/minors.h>
  18 #include <sound/info.h>
  19 #include <sound/control.h>
  20
  21 /* max number of user-defined controls */
  22 #define MAX_USER_CONTROLS       32
  23 #define MAX_CONTROL_COUNT       1028
  24
  25 struct snd_kctl_ioctl {
  26         struct list_head list;          /* list of all ioctls */
  27         snd_kctl_ioctl_func_t fioctl;
  28 };
  29
  30 static DECLARE_RWSEM(snd_ioctl_rwsem);
  31 static LIST_HEAD(snd_control_ioctls);
  32 #ifdef CONFIG_COMPAT
  33 static LIST_HEAD(snd_control_compat_ioctls);
  34 #endif
  35
  36 static int snd_ctl_open(struct inode *inode, struct file *file)
  37 {
  38         unsigned long flags;
  39         struct snd_card *card;
  40         struct snd_ctl_file *ctl;
  41         int i, err;
  42
  43         err = stream_open(inode, file);
  44         if (err < 0)
  45                 return err;
  46
  47         card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
  48         if (!card) {
  49                 err = -ENODEV;
  50                 goto __error1;
  51         }
  52         err = snd_card_file_add(card, file);
  53         if (err < 0) {
  54                 err = -ENODEV;
  55                 goto __error1;
  56         }
  57         if (!try_module_get(card->module)) {
  58                 err = -EFAULT;
  59                 goto __error2;
  60         }
  61         ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
  62         if (ctl == NULL) {
  63                 err = -ENOMEM;
  64                 goto __error;
  65         }
  66         INIT_LIST_HEAD(&ctl->events);
  67         init_waitqueue_head(&ctl->change_sleep);
  68         spin_lock_init(&ctl->read_lock);
  69         ctl->card = card;
  70         for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
  71                 ctl->preferred_subdevice[i] = -1;
  72         ctl->pid = get_pid(task_pid(current));
  73         file->private_data = ctl;
  74         write_lock_irqsave(&card->ctl_files_rwlock, flags);
  75         list_add_tail(&ctl->list, &card->ctl_files);
  76         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
  77         snd_card_unref(card);
  78         return 0;
  79
  80       __error:
  81         module_put(card->module);
  82       __error2:
  83         snd_card_file_remove(card, file);
  84       __error1:
  85         if (card)
  86                 snd_card_unref(card);
  87         return err;
  88 }
  89
  90 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
  91 {
  92         unsigned long flags;
  93         struct snd_kctl_event *cread;
  94
  95         spin_lock_irqsave(&ctl->read_lock, flags);
  96         while (!list_empty(&ctl->events)) {
  97                 cread = snd_kctl_event(ctl->events.next);
  98                 list_del(&cread->list);
  99                 kfree(cread);
 100         }
 101         spin_unlock_irqrestore(&ctl->read_lock, flags);
 102 }
 103
 104 static int snd_ctl_release(struct inode *inode, struct file *file)
 105 {
 106         unsigned long flags;
 107         struct snd_card *card;
 108         struct snd_ctl_file *ctl;
 109         struct snd_kcontrol *control;
 110         unsigned int idx;
 111
 112         ctl = file->private_data;
 113         file->private_data = NULL;
 114         card = ctl->card;
 115         write_lock_irqsave(&card->ctl_files_rwlock, flags);
 116         list_del(&ctl->list);
 117         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 118         down_write(&card->controls_rwsem);
 119         list_for_each_entry(control, &card->controls, list)
 120                 for (idx = 0; idx < control->count; idx++)
 121                         if (control->vd[idx].owner == ctl)
 122                                 control->vd[idx].owner = NULL;
 123         up_write(&card->controls_rwsem);
 124         snd_ctl_empty_read_queue(ctl);
 125         put_pid(ctl->pid);
 126         kfree(ctl);
 127         module_put(card->module);
 128         snd_card_file_remove(card, file);
 129         return 0;
 130 }
 131
 132 /**
 133  * snd_ctl_notify - Send notification to user-space for a control change
 134  * @card: the card to send notification
 135  * @mask: the event mask, SNDRV_CTL_EVENT_*
 136  * @id: the ctl element id to send notification
 137  *
 138  * This function adds an event record with the given id and mask, appends
 139  * to the list and wakes up the user-space for notification.  This can be
 140  * called in the atomic context.
 141  */
 142 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 143                     struct snd_ctl_elem_id *id)
 144 {
 145         unsigned long flags;
 146         struct snd_ctl_file *ctl;
 147         struct snd_kctl_event *ev;
 148
 149         if (snd_BUG_ON(!card || !id))
 150                 return;
 151         if (card->shutdown)
 152                 return;
 153         read_lock_irqsave(&card->ctl_files_rwlock, flags);
 154 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 155         card->mixer_oss_change_count++;
 156 #endif
 157         list_for_each_entry(ctl, &card->ctl_files, list) {
 158                 if (!ctl->subscribed)
 159                         continue;
 160                 spin_lock(&ctl->read_lock);
 161                 list_for_each_entry(ev, &ctl->events, list) {
 162                         if (ev->id.numid == id->numid) {
 163                                 ev->mask |= mask;
 164                                 goto _found;
 165                         }
 166                 }
 167                 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
 168                 if (ev) {
 169                         ev->id = *id;
 170                         ev->mask = mask;
 171                         list_add_tail(&ev->list, &ctl->events);
 172                 } else {
 173                         dev_err(card->dev, "No memory available to allocate event\n");
 174                 }
 175         _found:
 176                 wake_up(&ctl->change_sleep);
 177                 spin_unlock(&ctl->read_lock);
 178                 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
 179         }
 180         read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 181 }
 182 EXPORT_SYMBOL(snd_ctl_notify);
 183
 184 /**
 185  * snd_ctl_new - create a new control instance with some elements
 186  * @kctl: the pointer to store new control instance
 187  * @count: the number of elements in this control
 188  * @access: the default access flags for elements in this control
 189  * @file: given when locking these elements
 190  *
 191  * Allocates a memory object for a new control instance. The instance has
 192  * elements as many as the given number (@count). Each element has given
 193  * access permissions (@access). Each element is locked when @file is given.
 194  *
 195  * Return: 0 on success, error code on failure
 196  */
 197 static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,
 198                        unsigned int access, struct snd_ctl_file *file)
 199 {
 200         unsigned int idx;
 201
 202         if (count == 0 || count > MAX_CONTROL_COUNT)
 203                 return -EINVAL;
 204
 205         *kctl = kzalloc(struct_size(*kctl, vd, count), GFP_KERNEL);
 206         if (!*kctl)
 207                 return -ENOMEM;
 208
 209         for (idx = 0; idx < count; idx++) {
 210                 (*kctl)->vd[idx].access = access;
 211                 (*kctl)->vd[idx].owner = file;
 212         }
 213         (*kctl)->count = count;
 214
 215         return 0;
 216 }
 217
 218 /**
 219  * snd_ctl_new1 - create a control instance from the template
 220  * @ncontrol: the initialization record
 221  * @private_data: the private data to set
 222  *
 223  * Allocates a new struct snd_kcontrol instance and initialize from the given
 224  * template.  When the access field of ncontrol is 0, it's assumed as
 225  * READWRITE access. When the count field is 0, it's assumes as one.
 226  *
 227  * Return: The pointer of the newly generated instance, or %NULL on failure.
 228  */
 229 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
 230                                   void *private_data)
 231 {
 232         struct snd_kcontrol *kctl;
 233         unsigned int count;
 234         unsigned int access;
 235         int err;
 236
 237         if (snd_BUG_ON(!ncontrol || !ncontrol->info))
 238                 return NULL;
 239
 240         count = ncontrol->count;
 241         if (count == 0)
 242                 count = 1;
 243
 244         access = ncontrol->access;
 245         if (access == 0)
 246                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
 247         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
 248                    SNDRV_CTL_ELEM_ACCESS_VOLATILE |
 249                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
 250                    SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
 251                    SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND |
 252                    SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK |
 253                    SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK);
 254
 255         err = snd_ctl_new(&kctl, count, access, NULL);
 256         if (err < 0)
 257                 return NULL;
 258
 259         /* The 'numid' member is decided when calling snd_ctl_add(). */
 260         kctl->id.iface = ncontrol->iface;
 261         kctl->id.device = ncontrol->device;
 262         kctl->id.subdevice = ncontrol->subdevice;
 263         if (ncontrol->name) {
 264                 strlcpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name));
 265                 if (strcmp(ncontrol->name, kctl->id.name) != 0)
 266                         pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
 267                                 ncontrol->name, kctl->id.name);
 268         }
 269         kctl->id.index = ncontrol->index;
 270
 271         kctl->info = ncontrol->info;
 272         kctl->get = ncontrol->get;
 273         kctl->put = ncontrol->put;
 274         kctl->tlv.p = ncontrol->tlv.p;
 275
 276         kctl->private_value = ncontrol->private_value;
 277         kctl->private_data = private_data;
 278
 279         return kctl;
 280 }
 281 EXPORT_SYMBOL(snd_ctl_new1);
 282
 283 /**
 284  * snd_ctl_free_one - release the control instance
 285  * @kcontrol: the control instance
 286  *
 287  * Releases the control instance created via snd_ctl_new()
 288  * or snd_ctl_new1().
 289  * Don't call this after the control was added to the card.
 290  */
 291 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
 292 {
 293         if (kcontrol) {
 294                 if (kcontrol->private_free)
 295                         kcontrol->private_free(kcontrol);
 296                 kfree(kcontrol);
 297         }
 298 }
 299 EXPORT_SYMBOL(snd_ctl_free_one);
 300
 301 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
 302                                           unsigned int count)
 303 {
 304         struct snd_kcontrol *kctl;
 305
 306         /* Make sure that the ids assigned to the control do not wrap around */
 307         if (card->last_numid >= UINT_MAX - count)
 308                 card->last_numid = 0;
 309
 310         list_for_each_entry(kctl, &card->controls, list) {
 311                 if (kctl->id.numid < card->last_numid + 1 + count &&
 312                     kctl->id.numid + kctl->count > card->last_numid + 1) {
 313                         card->last_numid = kctl->id.numid + kctl->count - 1;
 314                         return true;
 315                 }
 316         }
 317         return false;
 318 }
 319
 320 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 321 {
 322         unsigned int iter = 100000;
 323
 324         while (snd_ctl_remove_numid_conflict(card, count)) {
 325                 if (--iter == 0) {
 326                         /* this situation is very unlikely */
 327                         dev_err(card->dev, "unable to allocate new control numid\n");
 328                         return -ENOMEM;
 329                 }
 330         }
 331         return 0;
 332 }
 333
 334 enum snd_ctl_add_mode {
 335         CTL_ADD_EXCLUSIVE, CTL_REPLACE, CTL_ADD_ON_REPLACE,
 336 };
 337
 338 /* add/replace a new kcontrol object; call with card->controls_rwsem locked */
 339 static int __snd_ctl_add_replace(struct snd_card *card,
 340                                  struct snd_kcontrol *kcontrol,
 341                                  enum snd_ctl_add_mode mode)
 342 {
 343         struct snd_ctl_elem_id id;
 344         unsigned int idx;
 345         unsigned int count;
 346         struct snd_kcontrol *old;
 347         int err;
 348
 349         id = kcontrol->id;
 350         if (id.index > UINT_MAX - kcontrol->count)
 351                 return -EINVAL;
 352
 353         old = snd_ctl_find_id(card, &id);
 354         if (!old) {
 355                 if (mode == CTL_REPLACE)
 356                         return -EINVAL;
 357         } else {
 358                 if (mode == CTL_ADD_EXCLUSIVE) {
 359                         dev_err(card->dev,
 360                                 "control %i:%i:%i:%s:%i is already present\n",
 361                                 id.iface, id.device, id.subdevice, id.name,
 362                                 id.index);
 363                         return -EBUSY;
 364                 }
 365
 366                 err = snd_ctl_remove(card, old);
 367                 if (err < 0)
 368                         return err;
 369         }
 370
 371         if (snd_ctl_find_hole(card, kcontrol->count) < 0)
 372                 return -ENOMEM;
 373
 374         list_add_tail(&kcontrol->list, &card->controls);
 375         card->controls_count += kcontrol->count;
 376         kcontrol->id.numid = card->last_numid + 1;
 377         card->last_numid += kcontrol->count;
 378
 379         id = kcontrol->id;
 380         count = kcontrol->count;
 381         for (idx = 0; idx < count; idx++, id.index++, id.numid++)
 382                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 383
 384         return 0;
 385 }
 386
 387 static int snd_ctl_add_replace(struct snd_card *card,
 388                                struct snd_kcontrol *kcontrol,
 389                                enum snd_ctl_add_mode mode)
 390 {
 391         int err = -EINVAL;
 392
 393         if (! kcontrol)
 394                 return err;
 395         if (snd_BUG_ON(!card || !kcontrol->info))
 396                 goto error;
 397
 398         down_write(&card->controls_rwsem);
 399         err = __snd_ctl_add_replace(card, kcontrol, mode);
 400         up_write(&card->controls_rwsem);
 401         if (err < 0)
 402                 goto error;
 403         return 0;
 404
 405  error:
 406         snd_ctl_free_one(kcontrol);
 407         return err;
 408 }
 409
 410 /**
 411  * snd_ctl_add - add the control instance to the card
 412  * @card: the card instance
 413  * @kcontrol: the control instance to add
 414  *
 415  * Adds the control instance created via snd_ctl_new() or
 416  * snd_ctl_new1() to the given card. Assigns also an unique
 417  * numid used for fast search.
 418  *
 419  * It frees automatically the control which cannot be added.
 420  *
 421  * Return: Zero if successful, or a negative error code on failure.
 422  *
 423  */
 424 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 425 {
 426         return snd_ctl_add_replace(card, kcontrol, CTL_ADD_EXCLUSIVE);
 427 }
 428 EXPORT_SYMBOL(snd_ctl_add);
 429
 430 /**
 431  * snd_ctl_replace - replace the control instance of the card
 432  * @card: the card instance
 433  * @kcontrol: the control instance to replace
 434  * @add_on_replace: add the control if not already added
 435  *
 436  * Replaces the given control.  If the given control does not exist
 437  * and the add_on_replace flag is set, the control is added.  If the
 438  * control exists, it is destroyed first.
 439  *
 440  * It frees automatically the control which cannot be added or replaced.
 441  *
 442  * Return: Zero if successful, or a negative error code on failure.
 443  */
 444 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
 445                     bool add_on_replace)
 446 {
 447         return snd_ctl_add_replace(card, kcontrol,
 448                                    add_on_replace ? CTL_ADD_ON_REPLACE : CTL_REPLACE);
 449 }
 450 EXPORT_SYMBOL(snd_ctl_replace);
 451
 452 /**
 453  * snd_ctl_remove - remove the control from the card and release it
 454  * @card: the card instance
 455  * @kcontrol: the control instance to remove
 456  *
 457  * Removes the control from the card and then releases the instance.
 458  * You don't need to call snd_ctl_free_one(). You must be in
 459  * the write lock - down_write(&card->controls_rwsem).
 460  *
 461  * Return: 0 if successful, or a negative error code on failure.
 462  */
 463 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 464 {
 465         struct snd_ctl_elem_id id;
 466         unsigned int idx;
 467
 468         if (snd_BUG_ON(!card || !kcontrol))
 469                 return -EINVAL;
 470         list_del(&kcontrol->list);
 471         card->controls_count -= kcontrol->count;
 472         id = kcontrol->id;
 473         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 474                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
 475         snd_ctl_free_one(kcontrol);
 476         return 0;
 477 }
 478 EXPORT_SYMBOL(snd_ctl_remove);
 479
 480 /**
 481  * snd_ctl_remove_id - remove the control of the given id and release it
 482  * @card: the card instance
 483  * @id: the control id to remove
 484  *
 485  * Finds the control instance with the given id, removes it from the
 486  * card list and releases it.
 487  *
 488  * Return: 0 if successful, or a negative error code on failure.
 489  */
 490 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 491 {
 492         struct snd_kcontrol *kctl;
 493         int ret;
 494
 495         down_write(&card->controls_rwsem);
 496         kctl = snd_ctl_find_id(card, id);
 497         if (kctl == NULL) {
 498                 up_write(&card->controls_rwsem);
 499                 return -ENOENT;
 500         }
 501         ret = snd_ctl_remove(card, kctl);
 502         up_write(&card->controls_rwsem);
 503         return ret;
 504 }
 505 EXPORT_SYMBOL(snd_ctl_remove_id);
 506
 507 /**
 508  * snd_ctl_remove_user_ctl - remove and release the unlocked user control
 509  * @file: active control handle
 510  * @id: the control id to remove
 511  *
 512  * Finds the control instance with the given id, removes it from the
 513  * card list and releases it.
 514  *
 515  * Return: 0 if successful, or a negative error code on failure.
 516  */
 517 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
 518                                    struct snd_ctl_elem_id *id)
 519 {
 520         struct snd_card *card = file->card;
 521         struct snd_kcontrol *kctl;
 522         int idx, ret;
 523
 524         down_write(&card->controls_rwsem);
 525         kctl = snd_ctl_find_id(card, id);
 526         if (kctl == NULL) {
 527                 ret = -ENOENT;
 528                 goto error;
 529         }
 530         if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
 531                 ret = -EINVAL;
 532                 goto error;
 533         }
 534         for (idx = 0; idx < kctl->count; idx++)
 535                 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
 536                         ret = -EBUSY;
 537                         goto error;
 538                 }
 539         ret = snd_ctl_remove(card, kctl);
 540         if (ret < 0)
 541                 goto error;
 542         card->user_ctl_count--;
 543 error:
 544         up_write(&card->controls_rwsem);
 545         return ret;
 546 }
 547
 548 /**
 549  * snd_ctl_activate_id - activate/inactivate the control of the given id
 550  * @card: the card instance
 551  * @id: the control id to activate/inactivate
 552  * @active: non-zero to activate
 553  *
 554  * Finds the control instance with the given id, and activate or
 555  * inactivate the control together with notification, if changed.
 556  * The given ID data is filled with full information.
 557  *
 558  * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
 559  */
 560 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
 561                         int active)
 562 {
 563         struct snd_kcontrol *kctl;
 564         struct snd_kcontrol_volatile *vd;
 565         unsigned int index_offset;
 566         int ret;
 567
 568         down_write(&card->controls_rwsem);
 569         kctl = snd_ctl_find_id(card, id);
 570         if (kctl == NULL) {
 571                 ret = -ENOENT;
 572                 goto unlock;
 573         }
 574         index_offset = snd_ctl_get_ioff(kctl, id);
 575         vd = &kctl->vd[index_offset];
 576         ret = 0;
 577         if (active) {
 578                 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
 579                         goto unlock;
 580                 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 581         } else {
 582                 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
 583                         goto unlock;
 584                 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 585         }
 586         snd_ctl_build_ioff(id, kctl, index_offset);
 587         ret = 1;
 588  unlock:
 589         up_write(&card->controls_rwsem);
 590         if (ret > 0)
 591                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
 592         return ret;
 593 }
 594 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
 595
 596 /**
 597  * snd_ctl_rename_id - replace the id of a control on the card
 598  * @card: the card instance
 599  * @src_id: the old id
 600  * @dst_id: the new id
 601  *
 602  * Finds the control with the old id from the card, and replaces the
 603  * id with the new one.
 604  *
 605  * Return: Zero if successful, or a negative error code on failure.
 606  */
 607 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 608                       struct snd_ctl_elem_id *dst_id)
 609 {
 610         struct snd_kcontrol *kctl;
 611
 612         down_write(&card->controls_rwsem);
 613         kctl = snd_ctl_find_id(card, src_id);
 614         if (kctl == NULL) {
 615                 up_write(&card->controls_rwsem);
 616                 return -ENOENT;
 617         }
 618         kctl->id = *dst_id;
 619         kctl->id.numid = card->last_numid + 1;
 620         card->last_numid += kctl->count;
 621         up_write(&card->controls_rwsem);
 622         return 0;
 623 }
 624 EXPORT_SYMBOL(snd_ctl_rename_id);
 625
 626 /**
 627  * snd_ctl_find_numid - find the control instance with the given number-id
 628  * @card: the card instance
 629  * @numid: the number-id to search
 630  *
 631  * Finds the control instance with the given number-id from the card.
 632  *
 633  * The caller must down card->controls_rwsem before calling this function
 634  * (if the race condition can happen).
 635  *
 636  * Return: The pointer of the instance if found, or %NULL if not.
 637  *
 638  */
 639 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 640 {
 641         struct snd_kcontrol *kctl;
 642
 643         if (snd_BUG_ON(!card || !numid))
 644                 return NULL;
 645         list_for_each_entry(kctl, &card->controls, list) {
 646                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 647                         return kctl;
 648         }
 649         return NULL;
 650 }
 651 EXPORT_SYMBOL(snd_ctl_find_numid);
 652
 653 /**
 654  * snd_ctl_find_id - find the control instance with the given id
 655  * @card: the card instance
 656  * @id: the id to search
 657  *
 658  * Finds the control instance with the given id from the card.
 659  *
 660  * The caller must down card->controls_rwsem before calling this function
 661  * (if the race condition can happen).
 662  *
 663  * Return: The pointer of the instance if found, or %NULL if not.
 664  *
 665  */
 666 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 667                                      struct snd_ctl_elem_id *id)
 668 {
 669         struct snd_kcontrol *kctl;
 670
 671         if (snd_BUG_ON(!card || !id))
 672                 return NULL;
 673         if (id->numid != 0)
 674                 return snd_ctl_find_numid(card, id->numid);
 675         list_for_each_entry(kctl, &card->controls, list) {
 676                 if (kctl->id.iface != id->iface)
 677                         continue;
 678                 if (kctl->id.device != id->device)
 679                         continue;
 680                 if (kctl->id.subdevice != id->subdevice)
 681                         continue;
 682                 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
 683                         continue;
 684                 if (kctl->id.index > id->index)
 685                         continue;
 686                 if (kctl->id.index + kctl->count <= id->index)
 687                         continue;
 688                 return kctl;
 689         }
 690         return NULL;
 691 }
 692 EXPORT_SYMBOL(snd_ctl_find_id);
 693
 694 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 695                              unsigned int cmd, void __user *arg)
 696 {
 697         struct snd_ctl_card_info *info;
 698
 699         info = kzalloc(sizeof(*info), GFP_KERNEL);
 700         if (! info)
 701                 return -ENOMEM;
 702         down_read(&snd_ioctl_rwsem);
 703         info->card = card->number;
 704         strlcpy(info->id, card->id, sizeof(info->id));
 705         strlcpy(info->driver, card->driver, sizeof(info->driver));
 706         strlcpy(info->name, card->shortname, sizeof(info->name));
 707         strlcpy(info->longname, card->longname, sizeof(info->longname));
 708         strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
 709         strlcpy(info->components, card->components, sizeof(info->components));
 710         up_read(&snd_ioctl_rwsem);
 711         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 712                 kfree(info);
 713                 return -EFAULT;
 714         }
 715         kfree(info);
 716         return 0;
 717 }
 718
 719 static int snd_ctl_elem_list(struct snd_card *card,
 720                              struct snd_ctl_elem_list *list)
 721 {
 722         struct snd_kcontrol *kctl;
 723         struct snd_ctl_elem_id id;
 724         unsigned int offset, space, jidx;
 725         int err = 0;
 726
 727         offset = list->offset;
 728         space = list->space;
 729
 730         down_read(&card->controls_rwsem);
 731         list->count = card->controls_count;
 732         list->used = 0;
 733         if (space > 0) {
 734                 list_for_each_entry(kctl, &card->controls, list) {
 735                         if (offset >= kctl->count) {
 736                                 offset -= kctl->count;
 737                                 continue;
 738                         }
 739                         for (jidx = offset; jidx < kctl->count; jidx++) {
 740                                 snd_ctl_build_ioff(&id, kctl, jidx);
 741                                 if (copy_to_user(list->pids + list->used, &id,
 742                                                  sizeof(id))) {
 743                                         err = -EFAULT;
 744                                         goto out;
 745                                 }
 746                                 list->used++;
 747                                 if (!--space)
 748                                         goto out;
 749                         }
 750                         offset = 0;
 751                 }
 752         }
 753  out:
 754         up_read(&card->controls_rwsem);
 755         return err;
 756 }
 757
 758 static int snd_ctl_elem_list_user(struct snd_card *card,
 759                                   struct snd_ctl_elem_list __user *_list)
 760 {
 761         struct snd_ctl_elem_list list;
 762         int err;
 763
 764         if (copy_from_user(&list, _list, sizeof(list)))
 765                 return -EFAULT;
 766         err = snd_ctl_elem_list(card, &list);
 767         if (err)
 768                 return err;
 769         if (copy_to_user(_list, &list, sizeof(list)))
 770                 return -EFAULT;
 771
 772         return 0;
 773 }
 774
 775 /* Check whether the given kctl info is valid */
 776 static int snd_ctl_check_elem_info(struct snd_card *card,
 777                                    const struct snd_ctl_elem_info *info)
 778 {
 779         static const unsigned int max_value_counts[] = {
 780                 [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = 128,
 781                 [SNDRV_CTL_ELEM_TYPE_INTEGER]   = 128,
 782                 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
 783                 [SNDRV_CTL_ELEM_TYPE_BYTES]     = 512,
 784                 [SNDRV_CTL_ELEM_TYPE_IEC958]    = 1,
 785                 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
 786         };
 787
 788         if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
 789             info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64) {
 790                 if (card)
 791                         dev_err(card->dev,
 792                                 "control %i:%i:%i:%s:%i: invalid type %d\n",
 793                                 info->id.iface, info->id.device,
 794                                 info->id.subdevice, info->id.name,
 795                                 info->id.index, info->type);
 796                 return -EINVAL;
 797         }
 798         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
 799             info->value.enumerated.items == 0) {
 800                 if (card)
 801                         dev_err(card->dev,
 802                                 "control %i:%i:%i:%s:%i: zero enum items\n",
 803                                 info->id.iface, info->id.device,
 804                                 info->id.subdevice, info->id.name,
 805                                 info->id.index);
 806                 return -EINVAL;
 807         }
 808         if (info->count > max_value_counts[info->type]) {
 809                 if (card)
 810                         dev_err(card->dev,
 811                                 "control %i:%i:%i:%s:%i: invalid count %d\n",
 812                                 info->id.iface, info->id.device,
 813                                 info->id.subdevice, info->id.name,
 814                                 info->id.index, info->count);
 815                 return -EINVAL;
 816         }
 817
 818         return 0;
 819 }
 820
 821 /* The capacity of struct snd_ctl_elem_value.value.*/
 822 static const unsigned int value_sizes[] = {
 823         [SNDRV_CTL_ELEM_TYPE_BOOLEAN]   = sizeof(long),
 824         [SNDRV_CTL_ELEM_TYPE_INTEGER]   = sizeof(long),
 825         [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),
 826         [SNDRV_CTL_ELEM_TYPE_BYTES]     = sizeof(unsigned char),
 827         [SNDRV_CTL_ELEM_TYPE_IEC958]    = sizeof(struct snd_aes_iec958),
 828         [SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),
 829 };
 830
 831 #ifdef CONFIG_SND_CTL_VALIDATION
 832 /* fill the remaining snd_ctl_elem_value data with the given pattern */
 833 static void fill_remaining_elem_value(struct snd_ctl_elem_value *control,
 834                                       struct snd_ctl_elem_info *info,
 835                                       u32 pattern)
 836 {
 837         size_t offset = value_sizes[info->type] * info->count;
 838
 839         offset = (offset + sizeof(u32) - 1) / sizeof(u32);
 840         memset32((u32 *)control->value.bytes.data + offset, pattern,
 841                  sizeof(control->value) / sizeof(u32) - offset);
 842 }
 843
 844 /* check whether the given integer ctl value is valid */
 845 static int sanity_check_int_value(struct snd_card *card,
 846                                   const struct snd_ctl_elem_value *control,
 847                                   const struct snd_ctl_elem_info *info,
 848                                   int i)
 849 {
 850         long long lval, lmin, lmax, lstep;
 851         u64 rem;
 852
 853         switch (info->type) {
 854         default:
 855         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
 856                 lval = control->value.integer.value[i];
 857                 lmin = 0;
 858                 lmax = 1;
 859                 lstep = 0;
 860                 break;
 861         case SNDRV_CTL_ELEM_TYPE_INTEGER:
 862                 lval = control->value.integer.value[i];
 863                 lmin = info->value.integer.min;
 864                 lmax = info->value.integer.max;
 865                 lstep = info->value.integer.step;
 866                 break;
 867         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
 868                 lval = control->value.integer64.value[i];
 869                 lmin = info->value.integer64.min;
 870                 lmax = info->value.integer64.max;
 871                 lstep = info->value.integer64.step;
 872                 break;
 873         case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
 874                 lval = control->value.enumerated.item[i];
 875                 lmin = 0;
 876                 lmax = info->value.enumerated.items - 1;
 877                 lstep = 0;
 878                 break;
 879         }
 880
 881         if (lval < lmin || lval > lmax) {
 882                 dev_err(card->dev,
 883                         "control %i:%i:%i:%s:%i: value out of range %lld (%lld/%lld) at count %i\n",
 884                         control->id.iface, control->id.device,
 885                         control->id.subdevice, control->id.name,
 886                         control->id.index, lval, lmin, lmax, i);
 887                 return -EINVAL;
 888         }
 889         if (lstep) {
 890                 div64_u64_rem(lval, lstep, &rem);
 891                 if (rem) {
 892                         dev_err(card->dev,
 893                                 "control %i:%i:%i:%s:%i: unaligned value %lld (step %lld) at count %i\n",
 894                                 control->id.iface, control->id.device,
 895                                 control->id.subdevice, control->id.name,
 896                                 control->id.index, lval, lstep, i);
 897                         return -EINVAL;
 898                 }
 899         }
 900
 901         return 0;
 902 }
 903
 904 /* perform sanity checks to the given snd_ctl_elem_value object */
 905 static int sanity_check_elem_value(struct snd_card *card,
 906                                    const struct snd_ctl_elem_value *control,
 907                                    const struct snd_ctl_elem_info *info,
 908                                    u32 pattern)
 909 {
 910         size_t offset;
 911         int i, ret = 0;
 912         u32 *p;
 913
 914         switch (info->type) {
 915         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
 916         case SNDRV_CTL_ELEM_TYPE_INTEGER:
 917         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
 918         case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
 919                 for (i = 0; i < info->count; i++) {
 920                         ret = sanity_check_int_value(card, control, info, i);
 921                         if (ret < 0)
 922                                 return ret;
 923                 }
 924                 break;
 925         default:
 926                 break;
 927         }
 928
 929         /* check whether the remaining area kept untouched */
 930         offset = value_sizes[info->type] * info->count;
 931         offset = (offset + sizeof(u32) - 1) / sizeof(u32);
 932         p = (u32 *)control->value.bytes.data + offset;
 933         for (; offset < sizeof(control->value) / sizeof(u32); offset++, p++) {
 934                 if (*p != pattern) {
 935                         ret = -EINVAL;
 936                         break;
 937                 }
 938                 *p = 0; /* clear the checked area */
 939         }
 940
 941         return ret;
 942 }
 943 #else
 944 static inline void fill_remaining_elem_value(struct snd_ctl_elem_value *control,
 945                                              struct snd_ctl_elem_info *info,
 946                                              u32 pattern)
 947 {
 948 }
 949
 950 static inline int sanity_check_elem_value(struct snd_card *card,
 951                                           struct snd_ctl_elem_value *control,
 952                                           struct snd_ctl_elem_info *info,
 953                                           u32 pattern)
 954 {
 955         return 0;
 956 }
 957 #endif
 958
 959 static int __snd_ctl_elem_info(struct snd_card *card,
 960                                struct snd_kcontrol *kctl,
 961                                struct snd_ctl_elem_info *info,
 962                                struct snd_ctl_file *ctl)
 963 {
 964         struct snd_kcontrol_volatile *vd;
 965         unsigned int index_offset;
 966         int result;
 967
 968 #ifdef CONFIG_SND_DEBUG
 969         info->access = 0;
 970 #endif
 971         result = kctl->info(kctl, info);
 972         if (result >= 0) {
 973                 snd_BUG_ON(info->access);
 974                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
 975                 vd = &kctl->vd[index_offset];
 976                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
 977                 info->access = vd->access;
 978                 if (vd->owner) {
 979                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
 980                         if (vd->owner == ctl)
 981                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
 982                         info->owner = pid_vnr(vd->owner->pid);
 983                 } else {
 984                         info->owner = -1;
 985                 }
 986                 if (!snd_ctl_skip_validation(info) &&
 987                     snd_ctl_check_elem_info(card, info) < 0)
 988                         result = -EINVAL;
 989         }
 990         return result;
 991 }
 992
 993 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 994                              struct snd_ctl_elem_info *info)
 995 {
 996         struct snd_card *card = ctl->card;
 997         struct snd_kcontrol *kctl;
 998         int result;
 999
1000         down_read(&card->controls_rwsem);
1001         kctl = snd_ctl_find_id(card, &info->id);
1002         if (kctl == NULL)
1003                 result = -ENOENT;
1004         else
1005                 result = __snd_ctl_elem_info(card, kctl, info, ctl);
1006         up_read(&card->controls_rwsem);
1007         return result;
1008 }
1009
1010 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
1011                                   struct snd_ctl_elem_info __user *_info)
1012 {
1013         struct snd_ctl_elem_info info;
1014         int result;
1015
1016         if (copy_from_user(&info, _info, sizeof(info)))
1017                 return -EFAULT;
1018         result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
1019         if (result < 0)
1020                 return result;
1021         result = snd_ctl_elem_info(ctl, &info);
1022         if (result < 0)
1023                 return result;
1024         /* drop internal access flags */
1025         info.access &= ~SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK;
1026         if (copy_to_user(_info, &info, sizeof(info)))
1027                 return -EFAULT;
1028         return result;
1029 }
1030
1031 static int snd_ctl_elem_read(struct snd_card *card,
1032                              struct snd_ctl_elem_value *control)
1033 {
1034         struct snd_kcontrol *kctl;
1035         struct snd_kcontrol_volatile *vd;
1036         unsigned int index_offset;
1037         struct snd_ctl_elem_info info;
1038         const u32 pattern = 0xdeadbeef;
1039         int ret;
1040
1041         kctl = snd_ctl_find_id(card, &control->id);
1042         if (kctl == NULL)
1043                 return -ENOENT;
1044
1045         index_offset = snd_ctl_get_ioff(kctl, &control->id);
1046         vd = &kctl->vd[index_offset];
1047         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) || kctl->get == NULL)
1048                 return -EPERM;
1049
1050         snd_ctl_build_ioff(&control->id, kctl, index_offset);
1051
1052 #ifdef CONFIG_SND_CTL_VALIDATION
1053         /* info is needed only for validation */
1054         memset(&info, 0, sizeof(info));
1055         info.id = control->id;
1056         ret = __snd_ctl_elem_info(card, kctl, &info, NULL);
1057         if (ret < 0)
1058                 return ret;
1059 #endif
1060
1061         if (!snd_ctl_skip_validation(&info))
1062                 fill_remaining_elem_value(control, &info, pattern);
1063         ret = kctl->get(kctl, control);
1064         if (ret < 0)
1065                 return ret;
1066         if (!snd_ctl_skip_validation(&info) &&
1067             sanity_check_elem_value(card, control, &info, pattern) < 0) {
1068                 dev_err(card->dev,
1069                         "control %i:%i:%i:%s:%i: access overflow\n",
1070                         control->id.iface, control->id.device,
1071                         control->id.subdevice, control->id.name,
1072                         control->id.index);
1073                 return -EINVAL;
1074         }
1075         return ret;
1076 }
1077
1078 static int snd_ctl_elem_read_user(struct snd_card *card,
1079                                   struct snd_ctl_elem_value __user *_control)
1080 {
1081         struct snd_ctl_elem_value *control;
1082         int result;
1083
1084         control = memdup_user(_control, sizeof(*control));
1085         if (IS_ERR(control))
1086                 return PTR_ERR(control);
1087
1088         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
1089         if (result < 0)
1090                 goto error;
1091
1092         down_read(&card->controls_rwsem);
1093         result = snd_ctl_elem_read(card, control);
1094         up_read(&card->controls_rwsem);
1095         if (result < 0)
1096                 goto error;
1097
1098         if (copy_to_user(_control, control, sizeof(*control)))
1099                 result = -EFAULT;
1100  error:
1101         kfree(control);
1102         return result;
1103 }
1104
1105 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
1106                               struct snd_ctl_elem_value *control)
1107 {
1108         struct snd_kcontrol *kctl;
1109         struct snd_kcontrol_volatile *vd;
1110         unsigned int index_offset;
1111         int result;
1112
1113         kctl = snd_ctl_find_id(card, &control->id);
1114         if (kctl == NULL)
1115                 return -ENOENT;
1116
1117         index_offset = snd_ctl_get_ioff(kctl, &control->id);
1118         vd = &kctl->vd[index_offset];
1119         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) || kctl->put == NULL ||
1120             (file && vd->owner && vd->owner != file)) {
1121                 return -EPERM;
1122         }
1123
1124         snd_ctl_build_ioff(&control->id, kctl, index_offset);
1125         result = kctl->put(kctl, control);
1126         if (result < 0)
1127                 return result;
1128
1129         if (result > 0) {
1130                 struct snd_ctl_elem_id id = control->id;
1131                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &id);
1132         }
1133
1134         return 0;
1135 }
1136
1137 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
1138                                    struct snd_ctl_elem_value __user *_control)
1139 {
1140         struct snd_ctl_elem_value *control;
1141         struct snd_card *card;
1142         int result;
1143
1144         control = memdup_user(_control, sizeof(*control));
1145         if (IS_ERR(control))
1146                 return PTR_ERR(control);
1147
1148         card = file->card;
1149         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
1150         if (result < 0)
1151                 goto error;
1152
1153         down_write(&card->controls_rwsem);
1154         result = snd_ctl_elem_write(card, file, control);
1155         up_write(&card->controls_rwsem);
1156         if (result < 0)
1157                 goto error;
1158
1159         if (copy_to_user(_control, control, sizeof(*control)))
1160                 result = -EFAULT;
1161  error:
1162         kfree(control);
1163         return result;
1164 }
1165
1166 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
1167                              struct snd_ctl_elem_id __user *_id)
1168 {
1169         struct snd_card *card = file->card;
1170         struct snd_ctl_elem_id id;
1171         struct snd_kcontrol *kctl;
1172         struct snd_kcontrol_volatile *vd;
1173         int result;
1174
1175         if (copy_from_user(&id, _id, sizeof(id)))
1176                 return -EFAULT;
1177         down_write(&card->controls_rwsem);
1178         kctl = snd_ctl_find_id(card, &id);
1179         if (kctl == NULL) {
1180                 result = -ENOENT;
1181         } else {
1182                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1183                 if (vd->owner != NULL)
1184                         result = -EBUSY;
1185                 else {
1186                         vd->owner = file;
1187                         result = 0;
1188                 }
1189         }
1190         up_write(&card->controls_rwsem);
1191         return result;
1192 }
1193
1194 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
1195                                struct snd_ctl_elem_id __user *_id)
1196 {
1197         struct snd_card *card = file->card;
1198         struct snd_ctl_elem_id id;
1199         struct snd_kcontrol *kctl;
1200         struct snd_kcontrol_volatile *vd;
1201         int result;
1202
1203         if (copy_from_user(&id, _id, sizeof(id)))
1204                 return -EFAULT;
1205         down_write(&card->controls_rwsem);
1206         kctl = snd_ctl_find_id(card, &id);
1207         if (kctl == NULL) {
1208                 result = -ENOENT;
1209         } else {
1210                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1211                 if (vd->owner == NULL)
1212                         result = -EINVAL;
1213                 else if (vd->owner != file)
1214                         result = -EPERM;
1215                 else {
1216                         vd->owner = NULL;
1217                         result = 0;
1218                 }
1219         }
1220         up_write(&card->controls_rwsem);
1221         return result;
1222 }
1223
1224 struct user_element {
1225         struct snd_ctl_elem_info info;
1226         struct snd_card *card;
1227         char *elem_data;                /* element data */
1228         unsigned long elem_data_size;   /* size of element data in bytes */
1229         void *tlv_data;                 /* TLV data */
1230         unsigned long tlv_data_size;    /* TLV data size */
1231         void *priv_data;                /* private data (like strings for enumerated type) */
1232 };
1233
1234 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1235                                   struct snd_ctl_elem_info *uinfo)
1236 {
1237         struct user_element *ue = kcontrol->private_data;
1238         unsigned int offset;
1239
1240         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1241         *uinfo = ue->info;
1242         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1243
1244         return 0;
1245 }
1246
1247 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1248                                        struct snd_ctl_elem_info *uinfo)
1249 {
1250         struct user_element *ue = kcontrol->private_data;
1251         const char *names;
1252         unsigned int item;
1253         unsigned int offset;
1254
1255         item = uinfo->value.enumerated.item;
1256
1257         offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1258         *uinfo = ue->info;
1259         snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1260
1261         item = min(item, uinfo->value.enumerated.items - 1);
1262         uinfo->value.enumerated.item = item;
1263
1264         names = ue->priv_data;
1265         for (; item > 0; --item)
1266                 names += strlen(names) + 1;
1267         strcpy(uinfo->value.enumerated.name, names);
1268
1269         return 0;
1270 }
1271
1272 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1273                                  struct snd_ctl_elem_value *ucontrol)
1274 {
1275         struct user_element *ue = kcontrol->private_data;
1276         unsigned int size = ue->elem_data_size;
1277         char *src = ue->elem_data +
1278                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1279
1280         memcpy(&ucontrol->value, src, size);
1281         return 0;
1282 }
1283
1284 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1285                                  struct snd_ctl_elem_value *ucontrol)
1286 {
1287         int change;
1288         struct user_element *ue = kcontrol->private_data;
1289         unsigned int size = ue->elem_data_size;
1290         char *dst = ue->elem_data +
1291                         snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1292
1293         change = memcmp(&ucontrol->value, dst, size) != 0;
1294         if (change)
1295                 memcpy(dst, &ucontrol->value, size);
1296         return change;
1297 }
1298
1299 static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1300                             unsigned int size)
1301 {
1302         struct user_element *ue = kctl->private_data;
1303         unsigned int *container;
1304         struct snd_ctl_elem_id id;
1305         unsigned int mask = 0;
1306         int i;
1307         int change;
1308
1309         if (size > 1024 * 128)  /* sane value */
1310                 return -EINVAL;
1311
1312         container = vmemdup_user(buf, size);
1313         if (IS_ERR(container))
1314                 return PTR_ERR(container);
1315
1316         change = ue->tlv_data_size != size;
1317         if (!change)
1318                 change = memcmp(ue->tlv_data, container, size) != 0;
1319         if (!change) {
1320                 kvfree(container);
1321                 return 0;
1322         }
1323
1324         if (ue->tlv_data == NULL) {
1325                 /* Now TLV data is available. */
1326                 for (i = 0; i < kctl->count; ++i)
1327                         kctl->vd[i].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
1328                 mask = SNDRV_CTL_EVENT_MASK_INFO;
1329         }
1330
1331         kvfree(ue->tlv_data);
1332         ue->tlv_data = container;
1333         ue->tlv_data_size = size;
1334
1335         mask |= SNDRV_CTL_EVENT_MASK_TLV;
1336         for (i = 0; i < kctl->count; ++i) {
1337                 snd_ctl_build_ioff(&id, kctl, i);
1338                 snd_ctl_notify(ue->card, mask, &id);
1339         }
1340
1341         return change;
1342 }
1343
1344 static int read_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1345                          unsigned int size)
1346 {
1347         struct user_element *ue = kctl->private_data;
1348
1349         if (ue->tlv_data_size == 0 || ue->tlv_data == NULL)
1350                 return -ENXIO;
1351
1352         if (size < ue->tlv_data_size)
1353                 return -ENOSPC;
1354
1355         if (copy_to_user(buf, ue->tlv_data, ue->tlv_data_size))
1356                 return -EFAULT;
1357
1358         return 0;
1359 }
1360
1361 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kctl, int op_flag,
1362                                  unsigned int size, unsigned int __user *buf)
1363 {
1364         if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
1365                 return replace_user_tlv(kctl, buf, size);
1366         else
1367                 return read_user_tlv(kctl, buf, size);
1368 }
1369
1370 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1371 {
1372         char *names, *p;
1373         size_t buf_len, name_len;
1374         unsigned int i;
1375         const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1376
1377         if (ue->info.value.enumerated.names_length > 64 * 1024)
1378                 return -EINVAL;
1379
1380         names = vmemdup_user((const void __user *)user_ptrval,
1381                 ue->info.value.enumerated.names_length);
1382         if (IS_ERR(names))
1383                 return PTR_ERR(names);
1384
1385         /* check that there are enough valid names */
1386         buf_len = ue->info.value.enumerated.names_length;
1387         p = names;
1388         for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1389                 name_len = strnlen(p, buf_len);
1390                 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1391                         kvfree(names);
1392                         return -EINVAL;
1393                 }
1394                 p += name_len + 1;
1395                 buf_len -= name_len + 1;
1396         }
1397
1398         ue->priv_data = names;
1399         ue->info.value.enumerated.names_ptr = 0;
1400
1401         return 0;
1402 }
1403
1404 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1405 {
1406         struct user_element *ue = kcontrol->private_data;
1407
1408         kvfree(ue->tlv_data);
1409         kvfree(ue->priv_data);
1410         kfree(ue);
1411 }
1412
1413 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1414                             struct snd_ctl_elem_info *info, int replace)
1415 {
1416         struct snd_card *card = file->card;
1417         struct snd_kcontrol *kctl;
1418         unsigned int count;
1419         unsigned int access;
1420         long private_size;
1421         struct user_element *ue;
1422         unsigned int offset;
1423         int err;
1424
1425         if (!*info->id.name)
1426                 return -EINVAL;
1427         if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
1428                 return -EINVAL;
1429
1430         /* Delete a control to replace them if needed. */
1431         if (replace) {
1432                 info->id.numid = 0;
1433                 err = snd_ctl_remove_user_ctl(file, &info->id);
1434                 if (err)
1435                         return err;
1436         }
1437
1438         /*
1439          * The number of userspace controls are counted control by control,
1440          * not element by element.
1441          */
1442         if (card->user_ctl_count + 1 > MAX_USER_CONTROLS)
1443                 return -ENOMEM;
1444
1445         /* Check the number of elements for this userspace control. */
1446         count = info->owner;
1447         if (count == 0)
1448                 count = 1;
1449
1450         /* Arrange access permissions if needed. */
1451         access = info->access;
1452         if (access == 0)
1453                 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
1454         access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
1455                    SNDRV_CTL_ELEM_ACCESS_INACTIVE |
1456                    SNDRV_CTL_ELEM_ACCESS_TLV_WRITE);
1457
1458         /* In initial state, nothing is available as TLV container. */
1459         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1460                 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1461         access |= SNDRV_CTL_ELEM_ACCESS_USER;
1462
1463         /*
1464          * Check information and calculate the size of data specific to
1465          * this userspace control.
1466          */
1467         /* pass NULL to card for suppressing error messages */
1468         err = snd_ctl_check_elem_info(NULL, info);
1469         if (err < 0)
1470                 return err;
1471         /* user-space control doesn't allow zero-size data */
1472         if (info->count < 1)
1473                 return -EINVAL;
1474         private_size = value_sizes[info->type] * info->count;
1475
1476         /*
1477          * Keep memory object for this userspace control. After passing this
1478          * code block, the instance should be freed by snd_ctl_free_one().
1479          *
1480          * Note that these elements in this control are locked.
1481          */
1482         err = snd_ctl_new(&kctl, count, access, file);
1483         if (err < 0)
1484                 return err;
1485         memcpy(&kctl->id, &info->id, sizeof(kctl->id));
1486         kctl->private_data = kzalloc(sizeof(struct user_element) + private_size * count,
1487                                      GFP_KERNEL);
1488         if (kctl->private_data == NULL) {
1489                 kfree(kctl);
1490                 return -ENOMEM;
1491         }
1492         kctl->private_free = snd_ctl_elem_user_free;
1493
1494         /* Set private data for this userspace control. */
1495         ue = (struct user_element *)kctl->private_data;
1496         ue->card = card;
1497         ue->info = *info;
1498         ue->info.access = 0;
1499         ue->elem_data = (char *)ue + sizeof(*ue);
1500         ue->elem_data_size = private_size;
1501         if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1502                 err = snd_ctl_elem_init_enum_names(ue);
1503                 if (err < 0) {
1504                         snd_ctl_free_one(kctl);
1505                         return err;
1506                 }
1507         }
1508
1509         /* Set callback functions. */
1510         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1511                 kctl->info = snd_ctl_elem_user_enum_info;
1512         else
1513                 kctl->info = snd_ctl_elem_user_info;
1514         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1515                 kctl->get = snd_ctl_elem_user_get;
1516         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1517                 kctl->put = snd_ctl_elem_user_put;
1518         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1519                 kctl->tlv.c = snd_ctl_elem_user_tlv;
1520
1521         /* This function manage to free the instance on failure. */
1522         down_write(&card->controls_rwsem);
1523         err = __snd_ctl_add_replace(card, kctl, CTL_ADD_EXCLUSIVE);
1524         if (err < 0) {
1525                 snd_ctl_free_one(kctl);
1526                 goto unlock;
1527         }
1528         offset = snd_ctl_get_ioff(kctl, &info->id);
1529         snd_ctl_build_ioff(&info->id, kctl, offset);
1530         /*
1531          * Here we cannot fill any field for the number of elements added by
1532          * this operation because there're no specific fields. The usage of
1533          * 'owner' field for this purpose may cause any bugs to userspace
1534          * applications because the field originally means PID of a process
1535          * which locks the element.
1536          */
1537
1538         card->user_ctl_count++;
1539
1540  unlock:
1541         up_write(&card->controls_rwsem);
1542         return 0;
1543 }
1544
1545 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1546                                  struct snd_ctl_elem_info __user *_info, int replace)
1547 {
1548         struct snd_ctl_elem_info info;
1549         int err;
1550
1551         if (copy_from_user(&info, _info, sizeof(info)))
1552                 return -EFAULT;
1553         err = snd_ctl_elem_add(file, &info, replace);
1554         if (err < 0)
1555                 return err;
1556         if (copy_to_user(_info, &info, sizeof(info))) {
1557                 snd_ctl_remove_user_ctl(file, &info.id);
1558                 return -EFAULT;
1559         }
1560
1561         return 0;
1562 }
1563
1564 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1565                                struct snd_ctl_elem_id __user *_id)
1566 {
1567         struct snd_ctl_elem_id id;
1568
1569         if (copy_from_user(&id, _id, sizeof(id)))
1570                 return -EFAULT;
1571         return snd_ctl_remove_user_ctl(file, &id);
1572 }
1573
1574 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1575 {
1576         int subscribe;
1577         if (get_user(subscribe, ptr))
1578                 return -EFAULT;
1579         if (subscribe < 0) {
1580                 subscribe = file->subscribed;
1581                 if (put_user(subscribe, ptr))
1582                         return -EFAULT;
1583                 return 0;
1584         }
1585         if (subscribe) {
1586                 file->subscribed = 1;
1587                 return 0;
1588         } else if (file->subscribed) {
1589                 snd_ctl_empty_read_queue(file);
1590                 file->subscribed = 0;
1591         }
1592         return 0;
1593 }
1594
1595 static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,
1596                             struct snd_kcontrol *kctl,
1597                             struct snd_ctl_elem_id *id,
1598                             unsigned int __user *buf, unsigned int size)
1599 {
1600         static const struct {
1601                 int op;
1602                 int perm;
1603         } pairs[] = {
1604                 {SNDRV_CTL_TLV_OP_READ,  SNDRV_CTL_ELEM_ACCESS_TLV_READ},
1605                 {SNDRV_CTL_TLV_OP_WRITE, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE},
1606                 {SNDRV_CTL_TLV_OP_CMD,   SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},
1607         };
1608         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1609         int i;
1610
1611         /* Check support of the request for this element. */
1612         for (i = 0; i < ARRAY_SIZE(pairs); ++i) {
1613                 if (op_flag == pairs[i].op && (vd->access & pairs[i].perm))
1614                         break;
1615         }
1616         if (i == ARRAY_SIZE(pairs))
1617                 return -ENXIO;
1618
1619         if (kctl->tlv.c == NULL)
1620                 return -ENXIO;
1621
1622         /* Write and command operations are not allowed for locked element. */
1623         if (op_flag != SNDRV_CTL_TLV_OP_READ &&
1624             vd->owner != NULL && vd->owner != file)
1625                 return -EPERM;
1626
1627         return kctl->tlv.c(kctl, op_flag, size, buf);
1628 }
1629
1630 static int read_tlv_buf(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id,
1631                         unsigned int __user *buf, unsigned int size)
1632 {
1633         struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1634         unsigned int len;
1635
1636         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ))
1637                 return -ENXIO;
1638
1639         if (kctl->tlv.p == NULL)
1640                 return -ENXIO;
1641
1642         len = sizeof(unsigned int) * 2 + kctl->tlv.p[1];
1643         if (size < len)
1644                 return -ENOMEM;
1645
1646         if (copy_to_user(buf, kctl->tlv.p, len))
1647                 return -EFAULT;
1648
1649         return 0;
1650 }
1651
1652 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1653                              struct snd_ctl_tlv __user *buf,
1654                              int op_flag)
1655 {
1656         struct snd_ctl_tlv header;
1657         unsigned int __user *container;
1658         unsigned int container_size;
1659         struct snd_kcontrol *kctl;
1660         struct snd_ctl_elem_id id;
1661         struct snd_kcontrol_volatile *vd;
1662
1663         if (copy_from_user(&header, buf, sizeof(header)))
1664                 return -EFAULT;
1665
1666         /* In design of control core, numerical ID starts at 1. */
1667         if (header.numid == 0)
1668                 return -EINVAL;
1669
1670         /* At least, container should include type and length fields.  */
1671         if (header.length < sizeof(unsigned int) * 2)
1672                 return -EINVAL;
1673         container_size = header.length;
1674         container = buf->tlv;
1675
1676         kctl = snd_ctl_find_numid(file->card, header.numid);
1677         if (kctl == NULL)
1678                 return -ENOENT;
1679
1680         /* Calculate index of the element in this set. */
1681         id = kctl->id;
1682         snd_ctl_build_ioff(&id, kctl, header.numid - id.numid);
1683         vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1684
1685         if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1686                 return call_tlv_handler(file, op_flag, kctl, &id, container,
1687                                         container_size);
1688         } else {
1689                 if (op_flag == SNDRV_CTL_TLV_OP_READ) {
1690                         return read_tlv_buf(kctl, &id, container,
1691                                             container_size);
1692                 }
1693         }
1694
1695         /* Not supported. */
1696         return -ENXIO;
1697 }
1698
1699 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1700 {
1701         struct snd_ctl_file *ctl;
1702         struct snd_card *card;
1703         struct snd_kctl_ioctl *p;
1704         void __user *argp = (void __user *)arg;
1705         int __user *ip = argp;
1706         int err;
1707
1708         ctl = file->private_data;
1709         card = ctl->card;
1710         if (snd_BUG_ON(!card))
1711                 return -ENXIO;
1712         switch (cmd) {
1713         case SNDRV_CTL_IOCTL_PVERSION:
1714                 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1715         case SNDRV_CTL_IOCTL_CARD_INFO:
1716                 return snd_ctl_card_info(card, ctl, cmd, argp);
1717         case SNDRV_CTL_IOCTL_ELEM_LIST:
1718                 return snd_ctl_elem_list_user(card, argp);
1719         case SNDRV_CTL_IOCTL_ELEM_INFO:
1720                 return snd_ctl_elem_info_user(ctl, argp);
1721         case SNDRV_CTL_IOCTL_ELEM_READ:
1722                 return snd_ctl_elem_read_user(card, argp);
1723         case SNDRV_CTL_IOCTL_ELEM_WRITE:
1724                 return snd_ctl_elem_write_user(ctl, argp);
1725         case SNDRV_CTL_IOCTL_ELEM_LOCK:
1726                 return snd_ctl_elem_lock(ctl, argp);
1727         case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1728                 return snd_ctl_elem_unlock(ctl, argp);
1729         case SNDRV_CTL_IOCTL_ELEM_ADD:
1730                 return snd_ctl_elem_add_user(ctl, argp, 0);
1731         case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1732                 return snd_ctl_elem_add_user(ctl, argp, 1);
1733         case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1734                 return snd_ctl_elem_remove(ctl, argp);
1735         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1736                 return snd_ctl_subscribe_events(ctl, ip);
1737         case SNDRV_CTL_IOCTL_TLV_READ:
1738                 down_read(&ctl->card->controls_rwsem);
1739                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
1740                 up_read(&ctl->card->controls_rwsem);
1741                 return err;
1742         case SNDRV_CTL_IOCTL_TLV_WRITE:
1743                 down_write(&ctl->card->controls_rwsem);
1744                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
1745                 up_write(&ctl->card->controls_rwsem);
1746                 return err;
1747         case SNDRV_CTL_IOCTL_TLV_COMMAND:
1748                 down_write(&ctl->card->controls_rwsem);
1749                 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
1750                 up_write(&ctl->card->controls_rwsem);
1751                 return err;
1752         case SNDRV_CTL_IOCTL_POWER:
1753                 return -ENOPROTOOPT;
1754         case SNDRV_CTL_IOCTL_POWER_STATE:
1755 #ifdef CONFIG_PM
1756                 return put_user(card->power_state, ip) ? -EFAULT : 0;
1757 #else
1758                 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1759 #endif
1760         }
1761         down_read(&snd_ioctl_rwsem);
1762         list_for_each_entry(p, &snd_control_ioctls, list) {
1763                 err = p->fioctl(card, ctl, cmd, arg);
1764                 if (err != -ENOIOCTLCMD) {
1765                         up_read(&snd_ioctl_rwsem);
1766                         return err;
1767                 }
1768         }
1769         up_read(&snd_ioctl_rwsem);
1770         dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
1771         return -ENOTTY;
1772 }
1773
1774 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1775                             size_t count, loff_t * offset)
1776 {
1777         struct snd_ctl_file *ctl;
1778         int err = 0;
1779         ssize_t result = 0;
1780
1781         ctl = file->private_data;
1782         if (snd_BUG_ON(!ctl || !ctl->card))
1783                 return -ENXIO;
1784         if (!ctl->subscribed)
1785                 return -EBADFD;
1786         if (count < sizeof(struct snd_ctl_event))
1787                 return -EINVAL;
1788         spin_lock_irq(&ctl->read_lock);
1789         while (count >= sizeof(struct snd_ctl_event)) {
1790                 struct snd_ctl_event ev;
1791                 struct snd_kctl_event *kev;
1792                 while (list_empty(&ctl->events)) {
1793                         wait_queue_entry_t wait;
1794                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1795                                 err = -EAGAIN;
1796                                 goto __end_lock;
1797                         }
1798                         init_waitqueue_entry(&wait, current);
1799                         add_wait_queue(&ctl->change_sleep, &wait);
1800                         set_current_state(TASK_INTERRUPTIBLE);
1801                         spin_unlock_irq(&ctl->read_lock);
1802                         schedule();
1803                         remove_wait_queue(&ctl->change_sleep, &wait);
1804                         if (ctl->card->shutdown)
1805                                 return -ENODEV;
1806                         if (signal_pending(current))
1807                                 return -ERESTARTSYS;
1808                         spin_lock_irq(&ctl->read_lock);
1809                 }
1810                 kev = snd_kctl_event(ctl->events.next);
1811                 ev.type = SNDRV_CTL_EVENT_ELEM;
1812                 ev.data.elem.mask = kev->mask;
1813                 ev.data.elem.id = kev->id;
1814                 list_del(&kev->list);
1815                 spin_unlock_irq(&ctl->read_lock);
1816                 kfree(kev);
1817                 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1818                         err = -EFAULT;
1819                         goto __end;
1820                 }
1821                 spin_lock_irq(&ctl->read_lock);
1822                 buffer += sizeof(struct snd_ctl_event);
1823                 count -= sizeof(struct snd_ctl_event);
1824                 result += sizeof(struct snd_ctl_event);
1825         }
1826       __end_lock:
1827         spin_unlock_irq(&ctl->read_lock);
1828       __end:
1829         return result > 0 ? result : err;
1830 }
1831
1832 static __poll_t snd_ctl_poll(struct file *file, poll_table * wait)
1833 {
1834         __poll_t mask;
1835         struct snd_ctl_file *ctl;
1836
1837         ctl = file->private_data;
1838         if (!ctl->subscribed)
1839                 return 0;
1840         poll_wait(file, &ctl->change_sleep, wait);
1841
1842         mask = 0;
1843         if (!list_empty(&ctl->events))
1844                 mask |= EPOLLIN | EPOLLRDNORM;
1845
1846         return mask;
1847 }
1848
1849 /*
1850  * register the device-specific control-ioctls.
1851  * called from each device manager like pcm.c, hwdep.c, etc.
1852  */
1853 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1854 {
1855         struct snd_kctl_ioctl *pn;
1856
1857         pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1858         if (pn == NULL)
1859                 return -ENOMEM;
1860         pn->fioctl = fcn;
1861         down_write(&snd_ioctl_rwsem);
1862         list_add_tail(&pn->list, lists);
1863         up_write(&snd_ioctl_rwsem);
1864         return 0;
1865 }
1866
1867 /**
1868  * snd_ctl_register_ioctl - register the device-specific control-ioctls
1869  * @fcn: ioctl callback function
1870  *
1871  * called from each device manager like pcm.c, hwdep.c, etc.
1872  */
1873 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1874 {
1875         return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1876 }
1877 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1878
1879 #ifdef CONFIG_COMPAT
1880 /**
1881  * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
1882  * control-ioctls
1883  * @fcn: ioctl callback function
1884  */
1885 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1886 {
1887         return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1888 }
1889 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1890 #endif
1891
1892 /*
1893  * de-register the device-specific control-ioctls.
1894  */
1895 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1896                                      struct list_head *lists)
1897 {
1898         struct snd_kctl_ioctl *p;
1899
1900         if (snd_BUG_ON(!fcn))
1901                 return -EINVAL;
1902         down_write(&snd_ioctl_rwsem);
1903         list_for_each_entry(p, lists, list) {
1904                 if (p->fioctl == fcn) {
1905                         list_del(&p->list);
1906                         up_write(&snd_ioctl_rwsem);
1907                         kfree(p);
1908                         return 0;
1909                 }
1910         }
1911         up_write(&snd_ioctl_rwsem);
1912         snd_BUG();
1913         return -EINVAL;
1914 }
1915
1916 /**
1917  * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
1918  * @fcn: ioctl callback function to unregister
1919  */
1920 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1921 {
1922         return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1923 }
1924 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1925
1926 #ifdef CONFIG_COMPAT
1927 /**
1928  * snd_ctl_unregister_ioctl - de-register the device-specific compat 32bit
1929  * control-ioctls
1930  * @fcn: ioctl callback function to unregister
1931  */
1932 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1933 {
1934         return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1935 }
1936 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1937 #endif
1938
1939 static int snd_ctl_fasync(int fd, struct file * file, int on)
1940 {
1941         struct snd_ctl_file *ctl;
1942
1943         ctl = file->private_data;
1944         return fasync_helper(fd, file, on, &ctl->fasync);
1945 }
1946
1947 /* return the preferred subdevice number if already assigned;
1948  * otherwise return -1
1949  */
1950 int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
1951 {
1952         struct snd_ctl_file *kctl;
1953         int subdevice = -1;
1954         unsigned long flags;
1955
1956         read_lock_irqsave(&card->ctl_files_rwlock, flags);
1957         list_for_each_entry(kctl, &card->ctl_files, list) {
1958                 if (kctl->pid == task_pid(current)) {
1959                         subdevice = kctl->preferred_subdevice[type];
1960                         if (subdevice != -1)
1961                                 break;
1962                 }
1963         }
1964         read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
1965         return subdevice;
1966 }
1967 EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
1968
1969 /*
1970  * ioctl32 compat
1971  */
1972 #ifdef CONFIG_COMPAT
1973 #include "control_compat.c"
1974 #else
1975 #define snd_ctl_ioctl_compat    NULL
1976 #endif
1977
1978 /*
1979  *  INIT PART
1980  */
1981
1982 static const struct file_operations snd_ctl_f_ops =
1983 {
1984         .owner =        THIS_MODULE,
1985         .read =         snd_ctl_read,
1986         .open =         snd_ctl_open,
1987         .release =      snd_ctl_release,
1988         .llseek =       no_llseek,
1989         .poll =         snd_ctl_poll,
1990         .unlocked_ioctl =       snd_ctl_ioctl,
1991         .compat_ioctl = snd_ctl_ioctl_compat,
1992         .fasync =       snd_ctl_fasync,
1993 };
1994
1995 /*
1996  * registration of the control device
1997  */
1998 static int snd_ctl_dev_register(struct snd_device *device)
1999 {
2000         struct snd_card *card = device->device_data;
2001
2002         return snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
2003                                    &snd_ctl_f_ops, card, &card->ctl_dev);
2004 }
2005
2006 /*
2007  * disconnection of the control device
2008  */
2009 static int snd_ctl_dev_disconnect(struct snd_device *device)
2010 {
2011         struct snd_card *card = device->device_data;
2012         struct snd_ctl_file *ctl;
2013         unsigned long flags;
2014
2015         read_lock_irqsave(&card->ctl_files_rwlock, flags);
2016         list_for_each_entry(ctl, &card->ctl_files, list) {
2017                 wake_up(&ctl->change_sleep);
2018                 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
2019         }
2020         read_unlock_irqrestore(&card->ctl_files_rwlock, flags);
2021
2022         return snd_unregister_device(&card->ctl_dev);
2023 }
2024
2025 /*
2026  * free all controls
2027  */
2028 static int snd_ctl_dev_free(struct snd_device *device)
2029 {
2030         struct snd_card *card = device->device_data;
2031         struct snd_kcontrol *control;
2032
2033         down_write(&card->controls_rwsem);
2034         while (!list_empty(&card->controls)) {
2035                 control = snd_kcontrol(card->controls.next);
2036                 snd_ctl_remove(card, control);
2037         }
2038         up_write(&card->controls_rwsem);
2039         put_device(&card->ctl_dev);
2040         return 0;
2041 }
2042
2043 /*
2044  * create control core:
2045  * called from init.c
2046  */
2047 int snd_ctl_create(struct snd_card *card)
2048 {
2049         static const struct snd_device_ops ops = {
2050                 .dev_free = snd_ctl_dev_free,
2051                 .dev_register = snd_ctl_dev_register,
2052                 .dev_disconnect = snd_ctl_dev_disconnect,
2053         };
2054         int err;
2055
2056         if (snd_BUG_ON(!card))
2057                 return -ENXIO;
2058         if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))
2059                 return -ENXIO;
2060
2061         snd_device_initialize(&card->ctl_dev, card);
2062         dev_set_name(&card->ctl_dev, "controlC%d", card->number);
2063
2064         err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
2065         if (err < 0)
2066                 put_device(&card->ctl_dev);
2067         return err;
2068 }
2069
2070 /*
2071  * Frequently used control callbacks/helpers
2072  */
2073
2074 /**
2075  * snd_ctl_boolean_mono_info - Helper function for a standard boolean info
2076  * callback with a mono channel
2077  * @kcontrol: the kcontrol instance
2078  * @uinfo: info to store
2079  *
2080  * This is a function that can be used as info callback for a standard
2081  * boolean control with a single mono channel.
2082  */
2083 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
2084                               struct snd_ctl_elem_info *uinfo)
2085 {
2086         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
2087         uinfo->count = 1;
2088         uinfo->value.integer.min = 0;
2089         uinfo->value.integer.max = 1;
2090         return 0;
2091 }
2092 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
2093
2094 /**
2095  * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
2096  * callback with stereo two channels
2097  * @kcontrol: the kcontrol instance
2098  * @uinfo: info to store
2099  *
2100  * This is a function that can be used as info callback for a standard
2101  * boolean control with stereo two channels.
2102  */
2103 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
2104                                 struct snd_ctl_elem_info *uinfo)
2105 {
2106         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
2107         uinfo->count = 2;
2108         uinfo->value.integer.min = 0;
2109         uinfo->value.integer.max = 1;
2110         return 0;
2111 }
2112 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
2113
2114 /**
2115  * snd_ctl_enum_info - fills the info structure for an enumerated control
2116  * @info: the structure to be filled
2117  * @channels: the number of the control's channels; often one
2118  * @items: the number of control values; also the size of @names
2119  * @names: an array containing the names of all control values
2120  *
2121  * Sets all required fields in @info to their appropriate values.
2122  * If the control's accessibility is not the default (readable and writable),
2123  * the caller has to fill @info->access.
2124  *
2125  * Return: Zero.
2126  */
2127 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
2128                       unsigned int items, const char *const names[])
2129 {
2130         info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
2131         info->count = channels;
2132         info->value.enumerated.items = items;
2133         if (!items)
2134                 return 0;
2135         if (info->value.enumerated.item >= items)
2136                 info->value.enumerated.item = items - 1;
2137         WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),
2138              "ALSA: too long item name '%s'\n",
2139              names[info->value.enumerated.item]);
2140         strlcpy(info->value.enumerated.name,
2141                 names[info->value.enumerated.item],
2142                 sizeof(info->value.enumerated.name));
2143         return 0;
2144 }
2145 EXPORT_SYMBOL(snd_ctl_enum_info);