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 <sound/core.h>
  29 #include <sound/minors.h>
  30 #include <sound/info.h>
  31 #include <sound/control.h>
  32
  33 /* max number of user-defined controls */
  34 #define MAX_USER_CONTROLS       32
  35 #define MAX_CONTROL_COUNT       1028
  36
  37 struct snd_kctl_ioctl {
  38         struct list_head list;          /* list of all ioctls */
  39         snd_kctl_ioctl_func_t fioctl;
  40 };
  41
  42 static DECLARE_RWSEM(snd_ioctl_rwsem);
  43 static LIST_HEAD(snd_control_ioctls);
  44 #ifdef CONFIG_COMPAT
  45 static LIST_HEAD(snd_control_compat_ioctls);
  46 #endif
  47
  48 static int snd_ctl_open(struct inode *inode, struct file *file)
  49 {
  50         unsigned long flags;
  51         struct snd_card *card;
  52         struct snd_ctl_file *ctl;
  53         int i, err;
  54
  55         err = nonseekable_open(inode, file);
  56         if (err < 0)
  57                 return err;
  58
  59         card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
  60         if (!card) {
  61                 err = -ENODEV;
  62                 goto __error1;
  63         }
  64         err = snd_card_file_add(card, file);
  65         if (err < 0) {
  66                 err = -ENODEV;
  67                 goto __error1;
  68         }
  69         if (!try_module_get(card->module)) {
  70                 err = -EFAULT;
  71                 goto __error2;
  72         }
  73         ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
  74         if (ctl == NULL) {
  75                 err = -ENOMEM;
  76                 goto __error;
  77         }
  78         INIT_LIST_HEAD(&ctl->events);
  79         init_waitqueue_head(&ctl->change_sleep);
  80         spin_lock_init(&ctl->read_lock);
  81         ctl->card = card;
  82         for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
  83                 ctl->preferred_subdevice[i] = -1;
  84         ctl->pid = get_pid(task_pid(current));
  85         file->private_data = ctl;
  86         write_lock_irqsave(&card->ctl_files_rwlock, flags);
  87         list_add_tail(&ctl->list, &card->ctl_files);
  88         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
  89         snd_card_unref(card);
  90         return 0;
  91
  92       __error:
  93         module_put(card->module);
  94       __error2:
  95         snd_card_file_remove(card, file);
  96       __error1:
  97         if (card)
  98                 snd_card_unref(card);
  99         return err;
 100 }
 101
 102 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
 103 {
 104         unsigned long flags;
 105         struct snd_kctl_event *cread;
 106
 107         spin_lock_irqsave(&ctl->read_lock, flags);
 108         while (!list_empty(&ctl->events)) {
 109                 cread = snd_kctl_event(ctl->events.next);
 110                 list_del(&cread->list);
 111                 kfree(cread);
 112         }
 113         spin_unlock_irqrestore(&ctl->read_lock, flags);
 114 }
 115
 116 static int snd_ctl_release(struct inode *inode, struct file *file)
 117 {
 118         unsigned long flags;
 119         struct snd_card *card;
 120         struct snd_ctl_file *ctl;
 121         struct snd_kcontrol *control;
 122         unsigned int idx;
 123
 124         ctl = file->private_data;
 125         file->private_data = NULL;
 126         card = ctl->card;
 127         write_lock_irqsave(&card->ctl_files_rwlock, flags);
 128         list_del(&ctl->list);
 129         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 130         down_write(&card->controls_rwsem);
 131         list_for_each_entry(control, &card->controls, list)
 132                 for (idx = 0; idx < control->count; idx++)
 133                         if (control->vd[idx].owner == ctl)
 134                                 control->vd[idx].owner = NULL;
 135         up_write(&card->controls_rwsem);
 136         snd_ctl_empty_read_queue(ctl);
 137         put_pid(ctl->pid);
 138         kfree(ctl);
 139         module_put(card->module);
 140         snd_card_file_remove(card, file);
 141         return 0;
 142 }
 143
 144 /**
 145  * snd_ctl_notify - Send notification to user-space for a control change
 146  * @card: the card to send notification
 147  * @mask: the event mask, SNDRV_CTL_EVENT_*
 148  * @id: the ctl element id to send notification
 149  *
 150  * This function adds an event record with the given id and mask, appends
 151  * to the list and wakes up the user-space for notification.  This can be
 152  * called in the atomic context.
 153  */
 154 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 155                     struct snd_ctl_elem_id *id)
 156 {
 157         unsigned long flags;
 158         struct snd_ctl_file *ctl;
 159         struct snd_kctl_event *ev;
 160
 161         if (snd_BUG_ON(!card || !id))
 162                 return;
 163         read_lock(&card->ctl_files_rwlock);
 164 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 165         card->mixer_oss_change_count++;
 166 #endif
 167         list_for_each_entry(ctl, &card->ctl_files, list) {
 168                 if (!ctl->subscribed)
 169                         continue;
 170                 spin_lock_irqsave(&ctl->read_lock, flags);
 171                 list_for_each_entry(ev, &ctl->events, list) {
 172                         if (ev->id.numid == id->numid) {
 173                                 ev->mask |= mask;
 174                                 goto _found;
 175                         }
 176                 }
 177                 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
 178                 if (ev) {
 179                         ev->id = *id;
 180                         ev->mask = mask;
 181                         list_add_tail(&ev->list, &ctl->events);
 182                 } else {
 183                         dev_err(card->dev, "No memory available to allocate event\n");
 184                 }
 185         _found:
 186                 wake_up(&ctl->change_sleep);
 187                 spin_unlock_irqrestore(&ctl->read_lock, flags);
 188                 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
 189         }
 190         read_unlock(&card->ctl_files_rwlock);
 191 }
 192 EXPORT_SYMBOL(snd_ctl_notify);
 193
 194 /**
 195  * snd_ctl_new - create a control instance from the template
 196  * @control: the control template
 197  * @access: the default control access
 198  *
 199  * Allocates a new struct snd_kcontrol instance and copies the given template
 200  * to the new instance. It does not copy volatile data (access).
 201  *
 202  * Return: The pointer of the new instance, or %NULL on failure.
 203  */
 204 static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control,
 205                                         unsigned int access)
 206 {
 207         struct snd_kcontrol *kctl;
 208         unsigned int idx;
 209
 210         if (snd_BUG_ON(!control || !control->count))
 211                 return NULL;
 212
 213         if (control->count > MAX_CONTROL_COUNT)
 214                 return NULL;
 215
 216         kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL);
 217         if (kctl == NULL) {
 218                 pr_err("ALSA: Cannot allocate control instance\n");
 219                 return NULL;
 220         }
 221         *kctl = *control;
 222         for (idx = 0; idx < kctl->count; idx++)
 223                 kctl->vd[idx].access = access;
 224         return kctl;
 225 }
 226
 227 /**
 228  * snd_ctl_new1 - create a control instance from the template
 229  * @ncontrol: the initialization record
 230  * @private_data: the private data to set
 231  *
 232  * Allocates a new struct snd_kcontrol instance and initialize from the given
 233  * template.  When the access field of ncontrol is 0, it's assumed as
 234  * READWRITE access. When the count field is 0, it's assumes as one.
 235  *
 236  * Return: The pointer of the newly generated instance, or %NULL on failure.
 237  */
 238 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
 239                                   void *private_data)
 240 {
 241         struct snd_kcontrol kctl;
 242         unsigned int access;
 243
 244         if (snd_BUG_ON(!ncontrol || !ncontrol->info))
 245                 return NULL;
 246         memset(&kctl, 0, sizeof(kctl));
 247         kctl.id.iface = ncontrol->iface;
 248         kctl.id.device = ncontrol->device;
 249         kctl.id.subdevice = ncontrol->subdevice;
 250         if (ncontrol->name) {
 251                 strlcpy(kctl.id.name, ncontrol->name, sizeof(kctl.id.name));
 252                 if (strcmp(ncontrol->name, kctl.id.name) != 0)
 253                         pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
 254                                 ncontrol->name, kctl.id.name);
 255         }
 256         kctl.id.index = ncontrol->index;
 257         kctl.count = ncontrol->count ? ncontrol->count : 1;
 258         access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
 259                  (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
 260                                       SNDRV_CTL_ELEM_ACCESS_VOLATILE|
 261                                       SNDRV_CTL_ELEM_ACCESS_INACTIVE|
 262                                       SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE|
 263                                       SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND|
 264                                       SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK));
 265         kctl.info = ncontrol->info;
 266         kctl.get = ncontrol->get;
 267         kctl.put = ncontrol->put;
 268         kctl.tlv.p = ncontrol->tlv.p;
 269         kctl.private_value = ncontrol->private_value;
 270         kctl.private_data = private_data;
 271         return snd_ctl_new(&kctl, access);
 272 }
 273 EXPORT_SYMBOL(snd_ctl_new1);
 274
 275 /**
 276  * snd_ctl_free_one - release the control instance
 277  * @kcontrol: the control instance
 278  *
 279  * Releases the control instance created via snd_ctl_new()
 280  * or snd_ctl_new1().
 281  * Don't call this after the control was added to the card.
 282  */
 283 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
 284 {
 285         if (kcontrol) {
 286                 if (kcontrol->private_free)
 287                         kcontrol->private_free(kcontrol);
 288                 kfree(kcontrol);
 289         }
 290 }
 291 EXPORT_SYMBOL(snd_ctl_free_one);
 292
 293 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
 294                                           unsigned int count)
 295 {
 296         struct snd_kcontrol *kctl;
 297
 298         /* Make sure that the ids assigned to the control do not wrap around */
 299         if (card->last_numid >= UINT_MAX - count)
 300                 card->last_numid = 0;
 301
 302         list_for_each_entry(kctl, &card->controls, list) {
 303                 if (kctl->id.numid < card->last_numid + 1 + count &&
 304                     kctl->id.numid + kctl->count > card->last_numid + 1) {
 305                         card->last_numid = kctl->id.numid + kctl->count - 1;
 306                         return true;
 307                 }
 308         }
 309         return false;
 310 }
 311
 312 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 313 {
 314         unsigned int iter = 100000;
 315
 316         while (snd_ctl_remove_numid_conflict(card, count)) {
 317                 if (--iter == 0) {
 318                         /* this situation is very unlikely */
 319                         dev_err(card->dev, "unable to allocate new control numid\n");
 320                         return -ENOMEM;
 321                 }
 322         }
 323         return 0;
 324 }
 325
 326 /**
 327  * snd_ctl_add - add the control instance to the card
 328  * @card: the card instance
 329  * @kcontrol: the control instance to add
 330  *
 331  * Adds the control instance created via snd_ctl_new() or
 332  * snd_ctl_new1() to the given card. Assigns also an unique
 333  * numid used for fast search.
 334  *
 335  * It frees automatically the control which cannot be added.
 336  *
 337  * Return: Zero if successful, or a negative error code on failure.
 338  *
 339  */
 340 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 341 {
 342         struct snd_ctl_elem_id id;
 343         unsigned int idx;
 344         unsigned int count;
 345         int err = -EINVAL;
 346
 347         if (! kcontrol)
 348                 return err;
 349         if (snd_BUG_ON(!card || !kcontrol->info))
 350                 goto error;
 351         id = kcontrol->id;
 352         if (id.index > UINT_MAX - kcontrol->count)
 353                 goto error;
 354
 355         down_write(&card->controls_rwsem);
 356         if (snd_ctl_find_id(card, &id)) {
 357                 up_write(&card->controls_rwsem);
 358                 dev_err(card->dev, "control %i:%i:%i:%s:%i is already present\n",
 359                                         id.iface,
 360                                         id.device,
 361                                         id.subdevice,
 362                                         id.name,
 363                                         id.index);
 364                 err = -EBUSY;
 365                 goto error;
 366         }
 367         if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 368                 up_write(&card->controls_rwsem);
 369                 err = -ENOMEM;
 370                 goto error;
 371         }
 372         list_add_tail(&kcontrol->list, &card->controls);
 373         card->controls_count += kcontrol->count;
 374         kcontrol->id.numid = card->last_numid + 1;
 375         card->last_numid += kcontrol->count;
 376         id = kcontrol->id;
 377         count = kcontrol->count;
 378         up_write(&card->controls_rwsem);
 379         for (idx = 0; idx < count; idx++, id.index++, id.numid++)
 380                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 381         return 0;
 382
 383  error:
 384         snd_ctl_free_one(kcontrol);
 385         return err;
 386 }
 387 EXPORT_SYMBOL(snd_ctl_add);
 388
 389 /**
 390  * snd_ctl_replace - replace the control instance of the card
 391  * @card: the card instance
 392  * @kcontrol: the control instance to replace
 393  * @add_on_replace: add the control if not already added
 394  *
 395  * Replaces the given control.  If the given control does not exist
 396  * and the add_on_replace flag is set, the control is added.  If the
 397  * control exists, it is destroyed first.
 398  *
 399  * It frees automatically the control which cannot be added or replaced.
 400  *
 401  * Return: Zero if successful, or a negative error code on failure.
 402  */
 403 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
 404                     bool add_on_replace)
 405 {
 406         struct snd_ctl_elem_id id;
 407         unsigned int count;
 408         unsigned int idx;
 409         struct snd_kcontrol *old;
 410         int ret;
 411
 412         if (!kcontrol)
 413                 return -EINVAL;
 414         if (snd_BUG_ON(!card || !kcontrol->info)) {
 415                 ret = -EINVAL;
 416                 goto error;
 417         }
 418         id = kcontrol->id;
 419         down_write(&card->controls_rwsem);
 420         old = snd_ctl_find_id(card, &id);
 421         if (!old) {
 422                 if (add_on_replace)
 423                         goto add;
 424                 up_write(&card->controls_rwsem);
 425                 ret = -EINVAL;
 426                 goto error;
 427         }
 428         ret = snd_ctl_remove(card, old);
 429         if (ret < 0) {
 430                 up_write(&card->controls_rwsem);
 431                 goto error;
 432         }
 433 add:
 434         if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 435                 up_write(&card->controls_rwsem);
 436                 ret = -ENOMEM;
 437                 goto error;
 438         }
 439         list_add_tail(&kcontrol->list, &card->controls);
 440         card->controls_count += kcontrol->count;
 441         kcontrol->id.numid = card->last_numid + 1;
 442         card->last_numid += kcontrol->count;
 443         id = kcontrol->id;
 444         count = kcontrol->count;
 445         up_write(&card->controls_rwsem);
 446         for (idx = 0; idx < count; idx++, id.index++, id.numid++)
 447                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 448         return 0;
 449
 450 error:
 451         snd_ctl_free_one(kcontrol);
 452         return ret;
 453 }
 454 EXPORT_SYMBOL(snd_ctl_replace);
 455
 456 /**
 457  * snd_ctl_remove - remove the control from the card and release it
 458  * @card: the card instance
 459  * @kcontrol: the control instance to remove
 460  *
 461  * Removes the control from the card and then releases the instance.
 462  * You don't need to call snd_ctl_free_one(). You must be in
 463  * the write lock - down_write(&card->controls_rwsem).
 464  *
 465  * Return: 0 if successful, or a negative error code on failure.
 466  */
 467 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 468 {
 469         struct snd_ctl_elem_id id;
 470         unsigned int idx;
 471
 472         if (snd_BUG_ON(!card || !kcontrol))
 473                 return -EINVAL;
 474         list_del(&kcontrol->list);
 475         card->controls_count -= kcontrol->count;
 476         id = kcontrol->id;
 477         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 478                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
 479         snd_ctl_free_one(kcontrol);
 480         return 0;
 481 }
 482 EXPORT_SYMBOL(snd_ctl_remove);
 483
 484 /**
 485  * snd_ctl_remove_id - remove the control of the given id and release it
 486  * @card: the card instance
 487  * @id: the control id to remove
 488  *
 489  * Finds the control instance with the given id, removes it from the
 490  * card list and releases it.
 491  *
 492  * Return: 0 if successful, or a negative error code on failure.
 493  */
 494 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 495 {
 496         struct snd_kcontrol *kctl;
 497         int ret;
 498
 499         down_write(&card->controls_rwsem);
 500         kctl = snd_ctl_find_id(card, id);
 501         if (kctl == NULL) {
 502                 up_write(&card->controls_rwsem);
 503                 return -ENOENT;
 504         }
 505         ret = snd_ctl_remove(card, kctl);
 506         up_write(&card->controls_rwsem);
 507         return ret;
 508 }
 509 EXPORT_SYMBOL(snd_ctl_remove_id);
 510
 511 /**
 512  * snd_ctl_remove_user_ctl - remove and release the unlocked user control
 513  * @file: active control handle
 514  * @id: the control id to remove
 515  *
 516  * Finds the control instance with the given id, removes it from the
 517  * card list and releases it.
 518  *
 519  * Return: 0 if successful, or a negative error code on failure.
 520  */
 521 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
 522                                    struct snd_ctl_elem_id *id)
 523 {
 524         struct snd_card *card = file->card;
 525         struct snd_kcontrol *kctl;
 526         int idx, ret;
 527
 528         down_write(&card->controls_rwsem);
 529         kctl = snd_ctl_find_id(card, id);
 530         if (kctl == NULL) {
 531                 ret = -ENOENT;
 532                 goto error;
 533         }
 534         if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
 535                 ret = -EINVAL;
 536                 goto error;
 537         }
 538         for (idx = 0; idx < kctl->count; idx++)
 539                 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
 540                         ret = -EBUSY;
 541                         goto error;
 542                 }
 543         ret = snd_ctl_remove(card, kctl);
 544         if (ret < 0)
 545                 goto error;
 546         card->user_ctl_count--;
 547 error:
 548         up_write(&card->controls_rwsem);
 549         return ret;
 550 }
 551
 552 /**
 553  * snd_ctl_activate_id - activate/inactivate the control of the given id
 554  * @card: the card instance
 555  * @id: the control id to activate/inactivate
 556  * @active: non-zero to activate
 557  *
 558  * Finds the control instance with the given id, and activate or
 559  * inactivate the control together with notification, if changed.
 560  *
 561  * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
 562  */
 563 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
 564                         int active)
 565 {
 566         struct snd_kcontrol *kctl;
 567         struct snd_kcontrol_volatile *vd;
 568         unsigned int index_offset;
 569         int ret;
 570
 571         down_write(&card->controls_rwsem);
 572         kctl = snd_ctl_find_id(card, id);
 573         if (kctl == NULL) {
 574                 ret = -ENOENT;
 575                 goto unlock;
 576         }
 577         index_offset = snd_ctl_get_ioff(kctl, id);
 578         vd = &kctl->vd[index_offset];
 579         ret = 0;
 580         if (active) {
 581                 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
 582                         goto unlock;
 583                 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 584         } else {
 585                 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
 586                         goto unlock;
 587                 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 588         }
 589         ret = 1;
 590  unlock:
 591         up_write(&card->controls_rwsem);
 592         if (ret > 0)
 593                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
 594         return ret;
 595 }
 596 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
 597
 598 /**
 599  * snd_ctl_rename_id - replace the id of a control on the card
 600  * @card: the card instance
 601  * @src_id: the old id
 602  * @dst_id: the new id
 603  *
 604  * Finds the control with the old id from the card, and replaces the
 605  * id with the new one.
 606  *
 607  * Return: Zero if successful, or a negative error code on failure.
 608  */
 609 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 610                       struct snd_ctl_elem_id *dst_id)
 611 {
 612         struct snd_kcontrol *kctl;
 613
 614         down_write(&card->controls_rwsem);
 615         kctl = snd_ctl_find_id(card, src_id);
 616         if (kctl == NULL) {
 617                 up_write(&card->controls_rwsem);
 618                 return -ENOENT;
 619         }
 620         kctl->id = *dst_id;
 621         kctl->id.numid = card->last_numid + 1;
 622         card->last_numid += kctl->count;
 623         up_write(&card->controls_rwsem);
 624         return 0;
 625 }
 626 EXPORT_SYMBOL(snd_ctl_rename_id);
 627
 628 /**
 629  * snd_ctl_find_numid - find the control instance with the given number-id
 630  * @card: the card instance
 631  * @numid: the number-id to search
 632  *
 633  * Finds the control instance with the given number-id from the card.
 634  *
 635  * The caller must down card->controls_rwsem before calling this function
 636  * (if the race condition can happen).
 637  *
 638  * Return: The pointer of the instance if found, or %NULL if not.
 639  *
 640  */
 641 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 642 {
 643         struct snd_kcontrol *kctl;
 644
 645         if (snd_BUG_ON(!card || !numid))
 646                 return NULL;
 647         list_for_each_entry(kctl, &card->controls, list) {
 648                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 649                         return kctl;
 650         }
 651         return NULL;
 652 }
 653 EXPORT_SYMBOL(snd_ctl_find_numid);
 654
 655 /**
 656  * snd_ctl_find_id - find the control instance with the given id
 657  * @card: the card instance
 658  * @id: the id to search
 659  *
 660  * Finds the control instance with the given id from the card.
 661  *
 662  * The caller must down card->controls_rwsem before calling this function
 663  * (if the race condition can happen).
 664  *
 665  * Return: The pointer of the instance if found, or %NULL if not.
 666  *
 667  */
 668 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 669                                      struct snd_ctl_elem_id *id)
 670 {
 671         struct snd_kcontrol *kctl;
 672
 673         if (snd_BUG_ON(!card || !id))
 674                 return NULL;
 675         if (id->numid != 0)
 676                 return snd_ctl_find_numid(card, id->numid);
 677         list_for_each_entry(kctl, &card->controls, list) {
 678                 if (kctl->id.iface != id->iface)
 679                         continue;
 680                 if (kctl->id.device != id->device)
 681                         continue;
 682                 if (kctl->id.subdevice != id->subdevice)
 683                         continue;
 684                 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
 685                         continue;
 686                 if (kctl->id.index > id->index)
 687                         continue;
 688                 if (kctl->id.index + kctl->count <= id->index)
 689                         continue;
 690                 return kctl;
 691         }
 692         return NULL;
 693 }
 694 EXPORT_SYMBOL(snd_ctl_find_id);
 695
 696 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 697                              unsigned int cmd, void __user *arg)
 698 {
 699         struct snd_ctl_card_info *info;
 700
 701         info = kzalloc(sizeof(*info), GFP_KERNEL);
 702         if (! info)
 703                 return -ENOMEM;
 704         down_read(&snd_ioctl_rwsem);
 705         info->card = card->number;
 706         strlcpy(info->id, card->id, sizeof(info->id));
 707         strlcpy(info->driver, card->driver, sizeof(info->driver));
 708         strlcpy(info->name, card->shortname, sizeof(info->name));
 709         strlcpy(info->longname, card->longname, sizeof(info->longname));
 710         strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
 711         strlcpy(info->components, card->components, sizeof(info->components));
 712         up_read(&snd_ioctl_rwsem);
 713         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 714                 kfree(info);
 715                 return -EFAULT;
 716         }
 717         kfree(info);
 718         return 0;
 719 }
 720
 721 static int snd_ctl_elem_list(struct snd_card *card,
 722                              struct snd_ctl_elem_list __user *_list)
 723 {
 724         struct list_head *plist;
 725         struct snd_ctl_elem_list list;
 726         struct snd_kcontrol *kctl;
 727         struct snd_ctl_elem_id *dst, *id;
 728         unsigned int offset, space, jidx;
 729
 730         if (copy_from_user(&list, _list, sizeof(list)))
 731                 return -EFAULT;
 732         offset = list.offset;
 733         space = list.space;
 734         /* try limit maximum space */
 735         if (space > 16384)
 736                 return -ENOMEM;
 737         if (space > 0) {
 738                 /* allocate temporary buffer for atomic operation */
 739                 dst = vmalloc(space * sizeof(struct snd_ctl_elem_id));
 740                 if (dst == NULL)
 741                         return -ENOMEM;
 742                 down_read(&card->controls_rwsem);
 743                 list.count = card->controls_count;
 744                 plist = card->controls.next;
 745                 while (plist != &card->controls) {
 746                         if (offset == 0)
 747                                 break;
 748                         kctl = snd_kcontrol(plist);
 749                         if (offset < kctl->count)
 750                                 break;
 751                         offset -= kctl->count;
 752                         plist = plist->next;
 753                 }
 754                 list.used = 0;
 755                 id = dst;
 756                 while (space > 0 && plist != &card->controls) {
 757                         kctl = snd_kcontrol(plist);
 758                         for (jidx = offset; space > 0 && jidx < kctl->count; jidx++) {
 759                                 snd_ctl_build_ioff(id, kctl, jidx);
 760                                 id++;
 761                                 space--;
 762                                 list.used++;
 763                         }
 764                         plist = plist->next;
 765                         offset = 0;
 766                 }
 767                 up_read(&card->controls_rwsem);
 768                 if (list.used > 0 &&
 769                     copy_to_user(list.pids, dst,
 770                                  list.used * sizeof(struct snd_ctl_elem_id))) {
 771                         vfree(dst);
 772                         return -EFAULT;
 773                 }
 774                 vfree(dst);
 775         } else {
 776                 down_read(&card->controls_rwsem);
 777                 list.count = card->controls_count;
 778                 up_read(&card->controls_rwsem);
 779         }
 780         if (copy_to_user(_list, &list, sizeof(list)))
 781                 return -EFAULT;
 782         return 0;
 783 }
 784
 785 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 786                              struct snd_ctl_elem_info *info)
 787 {
 788         struct snd_card *card = ctl->card;
 789         struct snd_kcontrol *kctl;
 790         struct snd_kcontrol_volatile *vd;
 791         unsigned int index_offset;
 792         int result;
 793
 794         down_read(&card->controls_rwsem);
 795         kctl = snd_ctl_find_id(card, &info->id);
 796         if (kctl == NULL) {
 797                 up_read(&card->controls_rwsem);
 798                 return -ENOENT;
 799         }
 800 #ifdef CONFIG_SND_DEBUG
 801         info->access = 0;
 802 #endif
 803         result = kctl->info(kctl, info);
 804         if (result >= 0) {
 805                 snd_BUG_ON(info->access);
 806                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
 807                 vd = &kctl->vd[index_offset];
 808                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
 809                 info->access = vd->access;
 810                 if (vd->owner) {
 811                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
 812                         if (vd->owner == ctl)
 813                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
 814                         info->owner = pid_vnr(vd->owner->pid);
 815                 } else {
 816                         info->owner = -1;
 817                 }
 818         }
 819         up_read(&card->controls_rwsem);
 820         return result;
 821 }
 822
 823 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
 824                                   struct snd_ctl_elem_info __user *_info)
 825 {
 826         struct snd_ctl_elem_info info;
 827         int result;
 828
 829         if (copy_from_user(&info, _info, sizeof(info)))
 830                 return -EFAULT;
 831         snd_power_lock(ctl->card);
 832         result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
 833         if (result >= 0)
 834                 result = snd_ctl_elem_info(ctl, &info);
 835         snd_power_unlock(ctl->card);
 836         if (result >= 0)
 837                 if (copy_to_user(_info, &info, sizeof(info)))
 838                         return -EFAULT;
 839         return result;
 840 }
 841
 842 static int snd_ctl_elem_read(struct snd_card *card,
 843                              struct snd_ctl_elem_value *control)
 844 {
 845         struct snd_kcontrol *kctl;
 846         struct snd_kcontrol_volatile *vd;
 847         unsigned int index_offset;
 848         int result;
 849
 850         down_read(&card->controls_rwsem);
 851         kctl = snd_ctl_find_id(card, &control->id);
 852         if (kctl == NULL) {
 853                 result = -ENOENT;
 854         } else {
 855                 index_offset = snd_ctl_get_ioff(kctl, &control->id);
 856                 vd = &kctl->vd[index_offset];
 857                 if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) &&
 858                     kctl->get != NULL) {
 859                         snd_ctl_build_ioff(&control->id, kctl, index_offset);
 860                         result = kctl->get(kctl, control);
 861                 } else
 862                         result = -EPERM;
 863         }
 864         up_read(&card->controls_rwsem);
 865         return result;
 866 }
 867
 868 static int snd_ctl_elem_read_user(struct snd_card *card,
 869                                   struct snd_ctl_elem_value __user *_control)
 870 {
 871         struct snd_ctl_elem_value *control;
 872         int result;
 873
 874         control = memdup_user(_control, sizeof(*control));
 875         if (IS_ERR(control))
 876                 return PTR_ERR(control);
 877
 878         snd_power_lock(card);
 879         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 880         if (result >= 0)
 881                 result = snd_ctl_elem_read(card, control);
 882         snd_power_unlock(card);
 883         if (result >= 0)
 884                 if (copy_to_user(_control, control, sizeof(*control)))
 885                         result = -EFAULT;
 886         kfree(control);
 887         return result;
 888 }
 889
 890 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
 891                               struct snd_ctl_elem_value *control)
 892 {
 893         struct snd_kcontrol *kctl;
 894         struct snd_kcontrol_volatile *vd;
 895         unsigned int index_offset;
 896         int result;
 897
 898         down_read(&card->controls_rwsem);
 899         kctl = snd_ctl_find_id(card, &control->id);
 900         if (kctl == NULL) {
 901                 result = -ENOENT;
 902         } else {
 903                 index_offset = snd_ctl_get_ioff(kctl, &control->id);
 904                 vd = &kctl->vd[index_offset];
 905                 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
 906                     kctl->put == NULL ||
 907                     (file && vd->owner && vd->owner != file)) {
 908                         result = -EPERM;
 909                 } else {
 910                         snd_ctl_build_ioff(&control->id, kctl, index_offset);
 911                         result = kctl->put(kctl, control);
 912                 }
 913                 if (result > 0) {
 914                         struct snd_ctl_elem_id id = control->id;
 915                         up_read(&card->controls_rwsem);
 916                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &id);
 917                         return 0;
 918                 }
 919         }
 920         up_read(&card->controls_rwsem);
 921         return result;
 922 }
 923
 924 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
 925                                    struct snd_ctl_elem_value __user *_control)
 926 {
 927         struct snd_ctl_elem_value *control;
 928         struct snd_card *card;
 929         int result;
 930
 931         control = memdup_user(_control, sizeof(*control));
 932         if (IS_ERR(control))
 933                 return PTR_ERR(control);
 934
 935         card = file->card;
 936         snd_power_lock(card);
 937         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 938         if (result >= 0)
 939                 result = snd_ctl_elem_write(card, file, control);
 940         snd_power_unlock(card);
 941         if (result >= 0)
 942                 if (copy_to_user(_control, control, sizeof(*control)))
 943                         result = -EFAULT;
 944         kfree(control);
 945         return result;
 946 }
 947
 948 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
 949                              struct snd_ctl_elem_id __user *_id)
 950 {
 951         struct snd_card *card = file->card;
 952         struct snd_ctl_elem_id id;
 953         struct snd_kcontrol *kctl;
 954         struct snd_kcontrol_volatile *vd;
 955         int result;
 956
 957         if (copy_from_user(&id, _id, sizeof(id)))
 958                 return -EFAULT;
 959         down_write(&card->controls_rwsem);
 960         kctl = snd_ctl_find_id(card, &id);
 961         if (kctl == NULL) {
 962                 result = -ENOENT;
 963         } else {
 964                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
 965                 if (vd->owner != NULL)
 966                         result = -EBUSY;
 967                 else {
 968                         vd->owner = file;
 969                         result = 0;
 970                 }
 971         }
 972         up_write(&card->controls_rwsem);
 973         return result;
 974 }
 975
 976 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
 977                                struct snd_ctl_elem_id __user *_id)
 978 {
 979         struct snd_card *card = file->card;
 980         struct snd_ctl_elem_id id;
 981         struct snd_kcontrol *kctl;
 982         struct snd_kcontrol_volatile *vd;
 983         int result;
 984
 985         if (copy_from_user(&id, _id, sizeof(id)))
 986                 return -EFAULT;
 987         down_write(&card->controls_rwsem);
 988         kctl = snd_ctl_find_id(card, &id);
 989         if (kctl == NULL) {
 990                 result = -ENOENT;
 991         } else {
 992                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
 993                 if (vd->owner == NULL)
 994                         result = -EINVAL;
 995                 else if (vd->owner != file)
 996                         result = -EPERM;
 997                 else {
 998                         vd->owner = NULL;
 999                         result = 0;
1000                 }
1001         }
1002         up_write(&card->controls_rwsem);
1003         return result;
1004 }
1005
1006 struct user_element {
1007         struct snd_ctl_elem_info info;
1008         struct snd_card *card;
1009         void *elem_data;                /* element data */
1010         unsigned long elem_data_size;   /* size of element data in bytes */
1011         void *tlv_data;                 /* TLV data */
1012         unsigned long tlv_data_size;    /* TLV data size */
1013         void *priv_data;                /* private data (like strings for enumerated type) */
1014 };
1015
1016 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1017                                   struct snd_ctl_elem_info *uinfo)
1018 {
1019         struct user_element *ue = kcontrol->private_data;
1020
1021         *uinfo = ue->info;
1022         return 0;
1023 }
1024
1025 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1026                                        struct snd_ctl_elem_info *uinfo)
1027 {
1028         struct user_element *ue = kcontrol->private_data;
1029         const char *names;
1030         unsigned int item;
1031
1032         item = uinfo->value.enumerated.item;
1033
1034         *uinfo = ue->info;
1035
1036         item = min(item, uinfo->value.enumerated.items - 1);
1037         uinfo->value.enumerated.item = item;
1038
1039         names = ue->priv_data;
1040         for (; item > 0; --item)
1041                 names += strlen(names) + 1;
1042         strcpy(uinfo->value.enumerated.name, names);
1043
1044         return 0;
1045 }
1046
1047 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1048                                  struct snd_ctl_elem_value *ucontrol)
1049 {
1050         struct user_element *ue = kcontrol->private_data;
1051
1052         mutex_lock(&ue->card->user_ctl_lock);
1053         memcpy(&ucontrol->value, ue->elem_data, ue->elem_data_size);
1054         mutex_unlock(&ue->card->user_ctl_lock);
1055         return 0;
1056 }
1057
1058 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1059                                  struct snd_ctl_elem_value *ucontrol)
1060 {
1061         int change;
1062         struct user_element *ue = kcontrol->private_data;
1063
1064         mutex_lock(&ue->card->user_ctl_lock);
1065         change = memcmp(&ucontrol->value, ue->elem_data, ue->elem_data_size) != 0;
1066         if (change)
1067                 memcpy(ue->elem_data, &ucontrol->value, ue->elem_data_size);
1068         mutex_unlock(&ue->card->user_ctl_lock);
1069         return change;
1070 }
1071
1072 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol,
1073                                  int op_flag,
1074                                  unsigned int size,
1075                                  unsigned int __user *tlv)
1076 {
1077         struct user_element *ue = kcontrol->private_data;
1078         int change = 0;
1079         void *new_data;
1080
1081         if (op_flag > 0) {
1082                 if (size > 1024 * 128)  /* sane value */
1083                         return -EINVAL;
1084
1085                 new_data = memdup_user(tlv, size);
1086                 if (IS_ERR(new_data))
1087                         return PTR_ERR(new_data);
1088                 mutex_lock(&ue->card->user_ctl_lock);
1089                 change = ue->tlv_data_size != size;
1090                 if (!change)
1091                         change = memcmp(ue->tlv_data, new_data, size);
1092                 kfree(ue->tlv_data);
1093                 ue->tlv_data = new_data;
1094                 ue->tlv_data_size = size;
1095                 mutex_unlock(&ue->card->user_ctl_lock);
1096         } else {
1097                 int ret = 0;
1098
1099                 mutex_lock(&ue->card->user_ctl_lock);
1100                 if (!ue->tlv_data_size || !ue->tlv_data) {
1101                         ret = -ENXIO;
1102                         goto err_unlock;
1103                 }
1104                 if (size < ue->tlv_data_size) {
1105                         ret = -ENOSPC;
1106                         goto err_unlock;
1107                 }
1108                 if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size))
1109                         ret = -EFAULT;
1110 err_unlock:
1111                 mutex_unlock(&ue->card->user_ctl_lock);
1112                 if (ret)
1113                         return ret;
1114         }
1115         return change;
1116 }
1117
1118 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1119 {
1120         char *names, *p;
1121         size_t buf_len, name_len;
1122         unsigned int i;
1123         const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1124
1125         if (ue->info.value.enumerated.names_length > 64 * 1024)
1126                 return -EINVAL;
1127
1128         names = memdup_user((const void __user *)user_ptrval,
1129                 ue->info.value.enumerated.names_length);
1130         if (IS_ERR(names))
1131                 return PTR_ERR(names);
1132
1133         /* check that there are enough valid names */
1134         buf_len = ue->info.value.enumerated.names_length;
1135         p = names;
1136         for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1137                 name_len = strnlen(p, buf_len);
1138                 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1139                         kfree(names);
1140                         return -EINVAL;
1141                 }
1142                 p += name_len + 1;
1143                 buf_len -= name_len + 1;
1144         }
1145
1146         ue->priv_data = names;
1147         ue->info.value.enumerated.names_ptr = 0;
1148
1149         return 0;
1150 }
1151
1152 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1153 {
1154         struct user_element *ue = kcontrol->private_data;
1155
1156         kfree(ue->tlv_data);
1157         kfree(ue->priv_data);
1158         kfree(ue);
1159 }
1160
1161 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1162                             struct snd_ctl_elem_info *info, int replace)
1163 {
1164         struct snd_card *card = file->card;
1165         struct snd_kcontrol kctl, *_kctl;
1166         unsigned int access;
1167         long private_size;
1168         struct user_element *ue;
1169         int idx, err;
1170
1171         if (info->count < 1)
1172                 return -EINVAL;
1173         if (!*info->id.name)
1174                 return -EINVAL;
1175         if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
1176                 return -EINVAL;
1177         access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
1178                 (info->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
1179                                  SNDRV_CTL_ELEM_ACCESS_INACTIVE|
1180                                  SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE));
1181         info->id.numid = 0;
1182         memset(&kctl, 0, sizeof(kctl));
1183
1184         if (replace) {
1185                 err = snd_ctl_remove_user_ctl(file, &info->id);
1186                 if (err)
1187                         return err;
1188         }
1189
1190         if (card->user_ctl_count >= MAX_USER_CONTROLS)
1191                 return -ENOMEM;
1192
1193         memcpy(&kctl.id, &info->id, sizeof(info->id));
1194         kctl.count = info->owner ? info->owner : 1;
1195         access |= SNDRV_CTL_ELEM_ACCESS_USER;
1196         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1197                 kctl.info = snd_ctl_elem_user_enum_info;
1198         else
1199                 kctl.info = snd_ctl_elem_user_info;
1200         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1201                 kctl.get = snd_ctl_elem_user_get;
1202         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1203                 kctl.put = snd_ctl_elem_user_put;
1204         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE) {
1205                 kctl.tlv.c = snd_ctl_elem_user_tlv;
1206                 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1207         }
1208         switch (info->type) {
1209         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
1210         case SNDRV_CTL_ELEM_TYPE_INTEGER:
1211                 private_size = sizeof(long);
1212                 if (info->count > 128)
1213                         return -EINVAL;
1214                 break;
1215         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1216                 private_size = sizeof(long long);
1217                 if (info->count > 64)
1218                         return -EINVAL;
1219                 break;
1220         case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
1221                 private_size = sizeof(unsigned int);
1222                 if (info->count > 128 || info->value.enumerated.items == 0)
1223                         return -EINVAL;
1224                 break;
1225         case SNDRV_CTL_ELEM_TYPE_BYTES:
1226                 private_size = sizeof(unsigned char);
1227                 if (info->count > 512)
1228                         return -EINVAL;
1229                 break;
1230         case SNDRV_CTL_ELEM_TYPE_IEC958:
1231                 private_size = sizeof(struct snd_aes_iec958);
1232                 if (info->count != 1)
1233                         return -EINVAL;
1234                 break;
1235         default:
1236                 return -EINVAL;
1237         }
1238         private_size *= info->count;
1239         ue = kzalloc(sizeof(struct user_element) + private_size, GFP_KERNEL);
1240         if (ue == NULL)
1241                 return -ENOMEM;
1242         ue->card = card;
1243         ue->info = *info;
1244         ue->info.access = 0;
1245         ue->elem_data = (char *)ue + sizeof(*ue);
1246         ue->elem_data_size = private_size;
1247         if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1248                 err = snd_ctl_elem_init_enum_names(ue);
1249                 if (err < 0) {
1250                         kfree(ue);
1251                         return err;
1252                 }
1253         }
1254         kctl.private_free = snd_ctl_elem_user_free;
1255         _kctl = snd_ctl_new(&kctl, access);
1256         if (_kctl == NULL) {
1257                 kfree(ue->priv_data);
1258                 kfree(ue);
1259                 return -ENOMEM;
1260         }
1261         _kctl->private_data = ue;
1262         for (idx = 0; idx < _kctl->count; idx++)
1263                 _kctl->vd[idx].owner = file;
1264         err = snd_ctl_add(card, _kctl);
1265         if (err < 0)
1266                 return err;
1267
1268         down_write(&card->controls_rwsem);
1269         card->user_ctl_count++;
1270         up_write(&card->controls_rwsem);
1271
1272         return 0;
1273 }
1274
1275 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1276                                  struct snd_ctl_elem_info __user *_info, int replace)
1277 {
1278         struct snd_ctl_elem_info info;
1279         if (copy_from_user(&info, _info, sizeof(info)))
1280                 return -EFAULT;
1281         return snd_ctl_elem_add(file, &info, replace);
1282 }
1283
1284 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1285                                struct snd_ctl_elem_id __user *_id)
1286 {
1287         struct snd_ctl_elem_id id;
1288
1289         if (copy_from_user(&id, _id, sizeof(id)))
1290                 return -EFAULT;
1291         return snd_ctl_remove_user_ctl(file, &id);
1292 }
1293
1294 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1295 {
1296         int subscribe;
1297         if (get_user(subscribe, ptr))
1298                 return -EFAULT;
1299         if (subscribe < 0) {
1300                 subscribe = file->subscribed;
1301                 if (put_user(subscribe, ptr))
1302                         return -EFAULT;
1303                 return 0;
1304         }
1305         if (subscribe) {
1306                 file->subscribed = 1;
1307                 return 0;
1308         } else if (file->subscribed) {
1309                 snd_ctl_empty_read_queue(file);
1310                 file->subscribed = 0;
1311         }
1312         return 0;
1313 }
1314
1315 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1316                              struct snd_ctl_tlv __user *_tlv,
1317                              int op_flag)
1318 {
1319         struct snd_card *card = file->card;
1320         struct snd_ctl_tlv tlv;
1321         struct snd_kcontrol *kctl;
1322         struct snd_kcontrol_volatile *vd;
1323         unsigned int len;
1324         int err = 0;
1325
1326         if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
1327                 return -EFAULT;
1328         if (tlv.length < sizeof(unsigned int) * 2)
1329                 return -EINVAL;
1330         down_read(&card->controls_rwsem);
1331         kctl = snd_ctl_find_numid(card, tlv.numid);
1332         if (kctl == NULL) {
1333                 err = -ENOENT;
1334                 goto __kctl_end;
1335         }
1336         if (kctl->tlv.p == NULL) {
1337                 err = -ENXIO;
1338                 goto __kctl_end;
1339         }
1340         vd = &kctl->vd[tlv.numid - kctl->id.numid];
1341         if ((op_flag == 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||
1342             (op_flag > 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||
1343             (op_flag < 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0)) {
1344                 err = -ENXIO;
1345                 goto __kctl_end;
1346         }
1347         if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1348                 if (vd->owner != NULL && vd->owner != file) {
1349                         err = -EPERM;
1350                         goto __kctl_end;
1351                 }
1352                 err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv);
1353                 if (err > 0) {
1354                         struct snd_ctl_elem_id id = kctl->id;
1355                         up_read(&card->controls_rwsem);
1356                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &id);
1357                         return 0;
1358                 }
1359         } else {
1360                 if (op_flag) {
1361                         err = -ENXIO;
1362                         goto __kctl_end;
1363                 }
1364                 len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);
1365                 if (tlv.length < len) {
1366                         err = -ENOMEM;
1367                         goto __kctl_end;
1368                 }
1369                 if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))
1370                         err = -EFAULT;
1371         }
1372       __kctl_end:
1373         up_read(&card->controls_rwsem);
1374         return err;
1375 }
1376
1377 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1378 {
1379         struct snd_ctl_file *ctl;
1380         struct snd_card *card;
1381         struct snd_kctl_ioctl *p;
1382         void __user *argp = (void __user *)arg;
1383         int __user *ip = argp;
1384         int err;
1385
1386         ctl = file->private_data;
1387         card = ctl->card;
1388         if (snd_BUG_ON(!card))
1389                 return -ENXIO;
1390         switch (cmd) {
1391         case SNDRV_CTL_IOCTL_PVERSION:
1392                 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1393         case SNDRV_CTL_IOCTL_CARD_INFO:
1394                 return snd_ctl_card_info(card, ctl, cmd, argp);
1395         case SNDRV_CTL_IOCTL_ELEM_LIST:
1396                 return snd_ctl_elem_list(card, argp);
1397         case SNDRV_CTL_IOCTL_ELEM_INFO:
1398                 return snd_ctl_elem_info_user(ctl, argp);
1399         case SNDRV_CTL_IOCTL_ELEM_READ:
1400                 return snd_ctl_elem_read_user(card, argp);
1401         case SNDRV_CTL_IOCTL_ELEM_WRITE:
1402                 return snd_ctl_elem_write_user(ctl, argp);
1403         case SNDRV_CTL_IOCTL_ELEM_LOCK:
1404                 return snd_ctl_elem_lock(ctl, argp);
1405         case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1406                 return snd_ctl_elem_unlock(ctl, argp);
1407         case SNDRV_CTL_IOCTL_ELEM_ADD:
1408                 return snd_ctl_elem_add_user(ctl, argp, 0);
1409         case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1410                 return snd_ctl_elem_add_user(ctl, argp, 1);
1411         case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1412                 return snd_ctl_elem_remove(ctl, argp);
1413         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1414                 return snd_ctl_subscribe_events(ctl, ip);
1415         case SNDRV_CTL_IOCTL_TLV_READ:
1416                 return snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
1417         case SNDRV_CTL_IOCTL_TLV_WRITE:
1418                 return snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
1419         case SNDRV_CTL_IOCTL_TLV_COMMAND:
1420                 return snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
1421         case SNDRV_CTL_IOCTL_POWER:
1422                 return -ENOPROTOOPT;
1423         case SNDRV_CTL_IOCTL_POWER_STATE:
1424 #ifdef CONFIG_PM
1425                 return put_user(card->power_state, ip) ? -EFAULT : 0;
1426 #else
1427                 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1428 #endif
1429         }
1430         down_read(&snd_ioctl_rwsem);
1431         list_for_each_entry(p, &snd_control_ioctls, list) {
1432                 err = p->fioctl(card, ctl, cmd, arg);
1433                 if (err != -ENOIOCTLCMD) {
1434                         up_read(&snd_ioctl_rwsem);
1435                         return err;
1436                 }
1437         }
1438         up_read(&snd_ioctl_rwsem);
1439         dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
1440         return -ENOTTY;
1441 }
1442
1443 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1444                             size_t count, loff_t * offset)
1445 {
1446         struct snd_ctl_file *ctl;
1447         int err = 0;
1448         ssize_t result = 0;
1449
1450         ctl = file->private_data;
1451         if (snd_BUG_ON(!ctl || !ctl->card))
1452                 return -ENXIO;
1453         if (!ctl->subscribed)
1454                 return -EBADFD;
1455         if (count < sizeof(struct snd_ctl_event))
1456                 return -EINVAL;
1457         spin_lock_irq(&ctl->read_lock);
1458         while (count >= sizeof(struct snd_ctl_event)) {
1459                 struct snd_ctl_event ev;
1460                 struct snd_kctl_event *kev;
1461                 while (list_empty(&ctl->events)) {
1462                         wait_queue_t wait;
1463                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1464                                 err = -EAGAIN;
1465                                 goto __end_lock;
1466                         }
1467                         init_waitqueue_entry(&wait, current);
1468                         add_wait_queue(&ctl->change_sleep, &wait);
1469                         set_current_state(TASK_INTERRUPTIBLE);
1470                         spin_unlock_irq(&ctl->read_lock);
1471                         schedule();
1472                         remove_wait_queue(&ctl->change_sleep, &wait);
1473                         if (ctl->card->shutdown)
1474                                 return -ENODEV;
1475                         if (signal_pending(current))
1476                                 return -ERESTARTSYS;
1477                         spin_lock_irq(&ctl->read_lock);
1478                 }
1479                 kev = snd_kctl_event(ctl->events.next);
1480                 ev.type = SNDRV_CTL_EVENT_ELEM;
1481                 ev.data.elem.mask = kev->mask;
1482                 ev.data.elem.id = kev->id;
1483                 list_del(&kev->list);
1484                 spin_unlock_irq(&ctl->read_lock);
1485                 kfree(kev);
1486                 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1487                         err = -EFAULT;
1488                         goto __end;
1489                 }
1490                 spin_lock_irq(&ctl->read_lock);
1491                 buffer += sizeof(struct snd_ctl_event);
1492                 count -= sizeof(struct snd_ctl_event);
1493                 result += sizeof(struct snd_ctl_event);
1494         }
1495       __end_lock:
1496         spin_unlock_irq(&ctl->read_lock);
1497       __end:
1498         return result > 0 ? result : err;
1499 }
1500
1501 static unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
1502 {
1503         unsigned int mask;
1504         struct snd_ctl_file *ctl;
1505
1506         ctl = file->private_data;
1507         if (!ctl->subscribed)
1508                 return 0;
1509         poll_wait(file, &ctl->change_sleep, wait);
1510
1511         mask = 0;
1512         if (!list_empty(&ctl->events))
1513                 mask |= POLLIN | POLLRDNORM;
1514
1515         return mask;
1516 }
1517
1518 /*
1519  * register the device-specific control-ioctls.
1520  * called from each device manager like pcm.c, hwdep.c, etc.
1521  */
1522 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1523 {
1524         struct snd_kctl_ioctl *pn;
1525
1526         pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1527         if (pn == NULL)
1528                 return -ENOMEM;
1529         pn->fioctl = fcn;
1530         down_write(&snd_ioctl_rwsem);
1531         list_add_tail(&pn->list, lists);
1532         up_write(&snd_ioctl_rwsem);
1533         return 0;
1534 }
1535
1536 /**
1537  * snd_ctl_register_ioctl - register the device-specific control-ioctls
1538  * @fcn: ioctl callback function
1539  *
1540  * called from each device manager like pcm.c, hwdep.c, etc.
1541  */
1542 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1543 {
1544         return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1545 }
1546 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1547
1548 #ifdef CONFIG_COMPAT
1549 /**
1550  * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
1551  * control-ioctls
1552  * @fcn: ioctl callback function
1553  */
1554 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1555 {
1556         return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1557 }
1558 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1559 #endif
1560
1561 /*
1562  * de-register the device-specific control-ioctls.
1563  */
1564 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1565                                      struct list_head *lists)
1566 {
1567         struct snd_kctl_ioctl *p;
1568
1569         if (snd_BUG_ON(!fcn))
1570                 return -EINVAL;
1571         down_write(&snd_ioctl_rwsem);
1572         list_for_each_entry(p, lists, list) {
1573                 if (p->fioctl == fcn) {
1574                         list_del(&p->list);
1575                         up_write(&snd_ioctl_rwsem);
1576                         kfree(p);
1577                         return 0;
1578                 }
1579         }
1580         up_write(&snd_ioctl_rwsem);
1581         snd_BUG();
1582         return -EINVAL;
1583 }
1584
1585 /**
1586  * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
1587  * @fcn: ioctl callback function to unregister
1588  */
1589 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1590 {
1591         return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1592 }
1593 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1594
1595 #ifdef CONFIG_COMPAT
1596 /**
1597  * snd_ctl_unregister_ioctl - de-register the device-specific compat 32bit
1598  * control-ioctls
1599  * @fcn: ioctl callback function to unregister
1600  */
1601 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1602 {
1603         return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1604 }
1605 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1606 #endif
1607
1608 static int snd_ctl_fasync(int fd, struct file * file, int on)
1609 {
1610         struct snd_ctl_file *ctl;
1611
1612         ctl = file->private_data;
1613         return fasync_helper(fd, file, on, &ctl->fasync);
1614 }
1615
1616 /* return the preferred subdevice number if already assigned;
1617  * otherwise return -1
1618  */
1619 int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
1620 {
1621         struct snd_ctl_file *kctl;
1622         int subdevice = -1;
1623
1624         read_lock(&card->ctl_files_rwlock);
1625         list_for_each_entry(kctl, &card->ctl_files, list) {
1626                 if (kctl->pid == task_pid(current)) {
1627                         subdevice = kctl->preferred_subdevice[type];
1628                         if (subdevice != -1)
1629                                 break;
1630                 }
1631         }
1632         read_unlock(&card->ctl_files_rwlock);
1633         return subdevice;
1634 }
1635 EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
1636
1637 /*
1638  * ioctl32 compat
1639  */
1640 #ifdef CONFIG_COMPAT
1641 #include "control_compat.c"
1642 #else
1643 #define snd_ctl_ioctl_compat    NULL
1644 #endif
1645
1646 /*
1647  *  INIT PART
1648  */
1649
1650 static const struct file_operations snd_ctl_f_ops =
1651 {
1652         .owner =        THIS_MODULE,
1653         .read =         snd_ctl_read,
1654         .open =         snd_ctl_open,
1655         .release =      snd_ctl_release,
1656         .llseek =       no_llseek,
1657         .poll =         snd_ctl_poll,
1658         .unlocked_ioctl =       snd_ctl_ioctl,
1659         .compat_ioctl = snd_ctl_ioctl_compat,
1660         .fasync =       snd_ctl_fasync,
1661 };
1662
1663 /*
1664  * registration of the control device
1665  */
1666 static int snd_ctl_dev_register(struct snd_device *device)
1667 {
1668         struct snd_card *card = device->device_data;
1669
1670         return snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
1671                                    &snd_ctl_f_ops, card, &card->ctl_dev);
1672 }
1673
1674 /*
1675  * disconnection of the control device
1676  */
1677 static int snd_ctl_dev_disconnect(struct snd_device *device)
1678 {
1679         struct snd_card *card = device->device_data;
1680         struct snd_ctl_file *ctl;
1681
1682         read_lock(&card->ctl_files_rwlock);
1683         list_for_each_entry(ctl, &card->ctl_files, list) {
1684                 wake_up(&ctl->change_sleep);
1685                 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1686         }
1687         read_unlock(&card->ctl_files_rwlock);
1688
1689         return snd_unregister_device(&card->ctl_dev);
1690 }
1691
1692 /*
1693  * free all controls
1694  */
1695 static int snd_ctl_dev_free(struct snd_device *device)
1696 {
1697         struct snd_card *card = device->device_data;
1698         struct snd_kcontrol *control;
1699
1700         down_write(&card->controls_rwsem);
1701         while (!list_empty(&card->controls)) {
1702                 control = snd_kcontrol(card->controls.next);
1703                 snd_ctl_remove(card, control);
1704         }
1705         up_write(&card->controls_rwsem);
1706         put_device(&card->ctl_dev);
1707         return 0;
1708 }
1709
1710 /*
1711  * create control core:
1712  * called from init.c
1713  */
1714 int snd_ctl_create(struct snd_card *card)
1715 {
1716         static struct snd_device_ops ops = {
1717                 .dev_free = snd_ctl_dev_free,
1718                 .dev_register = snd_ctl_dev_register,
1719                 .dev_disconnect = snd_ctl_dev_disconnect,
1720         };
1721         int err;
1722
1723         if (snd_BUG_ON(!card))
1724                 return -ENXIO;
1725         if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))
1726                 return -ENXIO;
1727
1728         snd_device_initialize(&card->ctl_dev, card);
1729         dev_set_name(&card->ctl_dev, "controlC%d", card->number);
1730
1731         err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1732         if (err < 0)
1733                 put_device(&card->ctl_dev);
1734         return err;
1735 }
1736
1737 /*
1738  * Frequently used control callbacks/helpers
1739  */
1740
1741 /**
1742  * snd_ctl_boolean_mono_info - Helper function for a standard boolean info
1743  * callback with a mono channel
1744  * @kcontrol: the kcontrol instance
1745  * @uinfo: info to store
1746  *
1747  * This is a function that can be used as info callback for a standard
1748  * boolean control with a single mono channel.
1749  */
1750 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
1751                               struct snd_ctl_elem_info *uinfo)
1752 {
1753         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1754         uinfo->count = 1;
1755         uinfo->value.integer.min = 0;
1756         uinfo->value.integer.max = 1;
1757         return 0;
1758 }
1759 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
1760
1761 /**
1762  * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
1763  * callback with stereo two channels
1764  * @kcontrol: the kcontrol instance
1765  * @uinfo: info to store
1766  *
1767  * This is a function that can be used as info callback for a standard
1768  * boolean control with stereo two channels.
1769  */
1770 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
1771                                 struct snd_ctl_elem_info *uinfo)
1772 {
1773         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1774         uinfo->count = 2;
1775         uinfo->value.integer.min = 0;
1776         uinfo->value.integer.max = 1;
1777         return 0;
1778 }
1779 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
1780
1781 /**
1782  * snd_ctl_enum_info - fills the info structure for an enumerated control
1783  * @info: the structure to be filled
1784  * @channels: the number of the control's channels; often one
1785  * @items: the number of control values; also the size of @names
1786  * @names: an array containing the names of all control values
1787  *
1788  * Sets all required fields in @info to their appropriate values.
1789  * If the control's accessibility is not the default (readable and writable),
1790  * the caller has to fill @info->access.
1791  *
1792  * Return: Zero.
1793  */
1794 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
1795                       unsigned int items, const char *const names[])
1796 {
1797         info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
1798         info->count = channels;
1799         info->value.enumerated.items = items;
1800         if (!items)
1801                 return 0;
1802         if (info->value.enumerated.item >= items)
1803                 info->value.enumerated.item = items - 1;
1804         WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),
1805              "ALSA: too long item name '%s'\n",
1806              names[info->value.enumerated.item]);
1807         strlcpy(info->value.enumerated.name,
1808                 names[info->value.enumerated.item],
1809                 sizeof(info->value.enumerated.name));
1810         return 0;
1811 }
1812 EXPORT_SYMBOL(snd_ctl_enum_info);