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 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         ctl->prefer_pcm_subdevice = -1;
  83         ctl->prefer_rawmidi_subdevice = -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 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 145                     struct snd_ctl_elem_id *id)
 146 {
 147         unsigned long flags;
 148         struct snd_ctl_file *ctl;
 149         struct snd_kctl_event *ev;
 150
 151         if (snd_BUG_ON(!card || !id))
 152                 return;
 153         read_lock(&card->ctl_files_rwlock);
 154 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 155         card->mixer_oss_change_count++;
 156 #endif
 157         list_for_each_entry(ctl, &card->ctl_files, list) {
 158                 if (!ctl->subscribed)
 159                         continue;
 160                 spin_lock_irqsave(&ctl->read_lock, flags);
 161                 list_for_each_entry(ev, &ctl->events, list) {
 162                         if (ev->id.numid == id->numid) {
 163                                 ev->mask |= mask;
 164                                 goto _found;
 165                         }
 166                 }
 167                 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
 168                 if (ev) {
 169                         ev->id = *id;
 170                         ev->mask = mask;
 171                         list_add_tail(&ev->list, &ctl->events);
 172                 } else {
 173                         dev_err(card->dev, "No memory available to allocate event\n");
 174                 }
 175         _found:
 176                 wake_up(&ctl->change_sleep);
 177                 spin_unlock_irqrestore(&ctl->read_lock, flags);
 178                 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
 179         }
 180         read_unlock(&card->ctl_files_rwlock);
 181 }
 182
 183 EXPORT_SYMBOL(snd_ctl_notify);
 184
 185 /**
 186  * snd_ctl_new - create a control instance from the template
 187  * @control: the control template
 188  * @access: the default control access
 189  *
 190  * Allocates a new struct snd_kcontrol instance and copies the given template
 191  * to the new instance. It does not copy volatile data (access).
 192  *
 193  * Return: The pointer of the new instance, or %NULL on failure.
 194  */
 195 static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control,
 196                                         unsigned int access)
 197 {
 198         struct snd_kcontrol *kctl;
 199         unsigned int idx;
 200
 201         if (snd_BUG_ON(!control || !control->count))
 202                 return NULL;
 203
 204         if (control->count > MAX_CONTROL_COUNT)
 205                 return NULL;
 206
 207         kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL);
 208         if (kctl == NULL) {
 209                 pr_err("ALSA: Cannot allocate control instance\n");
 210                 return NULL;
 211         }
 212         *kctl = *control;
 213         for (idx = 0; idx < kctl->count; idx++)
 214                 kctl->vd[idx].access = access;
 215         return kctl;
 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 access;
 234
 235         if (snd_BUG_ON(!ncontrol || !ncontrol->info))
 236                 return NULL;
 237         memset(&kctl, 0, sizeof(kctl));
 238         kctl.id.iface = ncontrol->iface;
 239         kctl.id.device = ncontrol->device;
 240         kctl.id.subdevice = ncontrol->subdevice;
 241         if (ncontrol->name) {
 242                 strlcpy(kctl.id.name, ncontrol->name, sizeof(kctl.id.name));
 243                 if (strcmp(ncontrol->name, kctl.id.name) != 0)
 244                         pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
 245                                 ncontrol->name, kctl.id.name);
 246         }
 247         kctl.id.index = ncontrol->index;
 248         kctl.count = ncontrol->count ? ncontrol->count : 1;
 249         access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
 250                  (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
 251                                       SNDRV_CTL_ELEM_ACCESS_VOLATILE|
 252                                       SNDRV_CTL_ELEM_ACCESS_INACTIVE|
 253                                       SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE|
 254                                       SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND|
 255                                       SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK));
 256         kctl.info = ncontrol->info;
 257         kctl.get = ncontrol->get;
 258         kctl.put = ncontrol->put;
 259         kctl.tlv.p = ncontrol->tlv.p;
 260         kctl.private_value = ncontrol->private_value;
 261         kctl.private_data = private_data;
 262         return snd_ctl_new(&kctl, access);
 263 }
 264
 265 EXPORT_SYMBOL(snd_ctl_new1);
 266
 267 /**
 268  * snd_ctl_free_one - release the control instance
 269  * @kcontrol: the control instance
 270  *
 271  * Releases the control instance created via snd_ctl_new()
 272  * or snd_ctl_new1().
 273  * Don't call this after the control was added to the card.
 274  */
 275 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
 276 {
 277         if (kcontrol) {
 278                 if (kcontrol->private_free)
 279                         kcontrol->private_free(kcontrol);
 280                 kfree(kcontrol);
 281         }
 282 }
 283
 284 EXPORT_SYMBOL(snd_ctl_free_one);
 285
 286 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
 287                                           unsigned int count)
 288 {
 289         struct snd_kcontrol *kctl;
 290
 291         list_for_each_entry(kctl, &card->controls, list) {
 292                 if (kctl->id.numid < card->last_numid + 1 + count &&
 293                     kctl->id.numid + kctl->count > card->last_numid + 1) {
 294                         card->last_numid = kctl->id.numid + kctl->count - 1;
 295                         return true;
 296                 }
 297         }
 298         return false;
 299 }
 300
 301 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 302 {
 303         unsigned int iter = 100000;
 304
 305         while (snd_ctl_remove_numid_conflict(card, count)) {
 306                 if (--iter == 0) {
 307                         /* this situation is very unlikely */
 308                         dev_err(card->dev, "unable to allocate new control numid\n");
 309                         return -ENOMEM;
 310                 }
 311         }
 312         return 0;
 313 }
 314
 315 /**
 316  * snd_ctl_add - add the control instance to the card
 317  * @card: the card instance
 318  * @kcontrol: the control instance to add
 319  *
 320  * Adds the control instance created via snd_ctl_new() or
 321  * snd_ctl_new1() to the given card. Assigns also an unique
 322  * numid used for fast search.
 323  *
 324  * It frees automatically the control which cannot be added.
 325  *
 326  * Return: Zero if successful, or a negative error code on failure.
 327  *
 328  */
 329 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 330 {
 331         struct snd_ctl_elem_id id;
 332         unsigned int idx;
 333         int err = -EINVAL;
 334
 335         if (! kcontrol)
 336                 return err;
 337         if (snd_BUG_ON(!card || !kcontrol->info))
 338                 goto error;
 339         id = kcontrol->id;
 340         down_write(&card->controls_rwsem);
 341         if (snd_ctl_find_id(card, &id)) {
 342                 up_write(&card->controls_rwsem);
 343                 dev_err(card->dev, "control %i:%i:%i:%s:%i is already present\n",
 344                                         id.iface,
 345                                         id.device,
 346                                         id.subdevice,
 347                                         id.name,
 348                                         id.index);
 349                 err = -EBUSY;
 350                 goto error;
 351         }
 352         if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 353                 up_write(&card->controls_rwsem);
 354                 err = -ENOMEM;
 355                 goto error;
 356         }
 357         list_add_tail(&kcontrol->list, &card->controls);
 358         card->controls_count += kcontrol->count;
 359         kcontrol->id.numid = card->last_numid + 1;
 360         card->last_numid += kcontrol->count;
 361         up_write(&card->controls_rwsem);
 362         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 363                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 364         return 0;
 365
 366  error:
 367         snd_ctl_free_one(kcontrol);
 368         return err;
 369 }
 370
 371 EXPORT_SYMBOL(snd_ctl_add);
 372
 373 /**
 374  * snd_ctl_replace - replace the control instance of the card
 375  * @card: the card instance
 376  * @kcontrol: the control instance to replace
 377  * @add_on_replace: add the control if not already added
 378  *
 379  * Replaces the given control.  If the given control does not exist
 380  * and the add_on_replace flag is set, the control is added.  If the
 381  * control exists, it is destroyed first.
 382  *
 383  * It frees automatically the control which cannot be added or replaced.
 384  *
 385  * Return: Zero if successful, or a negative error code on failure.
 386  */
 387 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
 388                     bool add_on_replace)
 389 {
 390         struct snd_ctl_elem_id id;
 391         unsigned int idx;
 392         struct snd_kcontrol *old;
 393         int ret;
 394
 395         if (!kcontrol)
 396                 return -EINVAL;
 397         if (snd_BUG_ON(!card || !kcontrol->info)) {
 398                 ret = -EINVAL;
 399                 goto error;
 400         }
 401         id = kcontrol->id;
 402         down_write(&card->controls_rwsem);
 403         old = snd_ctl_find_id(card, &id);
 404         if (!old) {
 405                 if (add_on_replace)
 406                         goto add;
 407                 up_write(&card->controls_rwsem);
 408                 ret = -EINVAL;
 409                 goto error;
 410         }
 411         ret = snd_ctl_remove(card, old);
 412         if (ret < 0) {
 413                 up_write(&card->controls_rwsem);
 414                 goto error;
 415         }
 416 add:
 417         if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 418                 up_write(&card->controls_rwsem);
 419                 ret = -ENOMEM;
 420                 goto error;
 421         }
 422         list_add_tail(&kcontrol->list, &card->controls);
 423         card->controls_count += kcontrol->count;
 424         kcontrol->id.numid = card->last_numid + 1;
 425         card->last_numid += kcontrol->count;
 426         up_write(&card->controls_rwsem);
 427         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 428                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 429         return 0;
 430
 431 error:
 432         snd_ctl_free_one(kcontrol);
 433         return ret;
 434 }
 435 EXPORT_SYMBOL(snd_ctl_replace);
 436
 437 /**
 438  * snd_ctl_remove - remove the control from the card and release it
 439  * @card: the card instance
 440  * @kcontrol: the control instance to remove
 441  *
 442  * Removes the control from the card and then releases the instance.
 443  * You don't need to call snd_ctl_free_one(). You must be in
 444  * the write lock - down_write(&card->controls_rwsem).
 445  *
 446  * Return: 0 if successful, or a negative error code on failure.
 447  */
 448 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 449 {
 450         struct snd_ctl_elem_id id;
 451         unsigned int idx;
 452
 453         if (snd_BUG_ON(!card || !kcontrol))
 454                 return -EINVAL;
 455         list_del(&kcontrol->list);
 456         card->controls_count -= kcontrol->count;
 457         id = kcontrol->id;
 458         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 459                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
 460         snd_ctl_free_one(kcontrol);
 461         return 0;
 462 }
 463
 464 EXPORT_SYMBOL(snd_ctl_remove);
 465
 466 /**
 467  * snd_ctl_remove_id - remove the control of the given id and release it
 468  * @card: the card instance
 469  * @id: the control id to remove
 470  *
 471  * Finds the control instance with the given id, removes it from the
 472  * card list and releases it.
 473  *
 474  * Return: 0 if successful, or a negative error code on failure.
 475  */
 476 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 477 {
 478         struct snd_kcontrol *kctl;
 479         int ret;
 480
 481         down_write(&card->controls_rwsem);
 482         kctl = snd_ctl_find_id(card, id);
 483         if (kctl == NULL) {
 484                 up_write(&card->controls_rwsem);
 485                 return -ENOENT;
 486         }
 487         ret = snd_ctl_remove(card, kctl);
 488         up_write(&card->controls_rwsem);
 489         return ret;
 490 }
 491
 492 EXPORT_SYMBOL(snd_ctl_remove_id);
 493
 494 /**
 495  * snd_ctl_remove_user_ctl - remove and release the unlocked user control
 496  * @file: active control handle
 497  * @id: the control id to remove
 498  *
 499  * Finds the control instance with the given id, removes it from the
 500  * card list and releases it.
 501  *
 502  * Return: 0 if successful, or a negative error code on failure.
 503  */
 504 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
 505                                    struct snd_ctl_elem_id *id)
 506 {
 507         struct snd_card *card = file->card;
 508         struct snd_kcontrol *kctl;
 509         int idx, ret;
 510
 511         down_write(&card->controls_rwsem);
 512         kctl = snd_ctl_find_id(card, id);
 513         if (kctl == NULL) {
 514                 ret = -ENOENT;
 515                 goto error;
 516         }
 517         if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
 518                 ret = -EINVAL;
 519                 goto error;
 520         }
 521         for (idx = 0; idx < kctl->count; idx++)
 522                 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
 523                         ret = -EBUSY;
 524                         goto error;
 525                 }
 526         ret = snd_ctl_remove(card, kctl);
 527         if (ret < 0)
 528                 goto error;
 529         card->user_ctl_count--;
 530 error:
 531         up_write(&card->controls_rwsem);
 532         return ret;
 533 }
 534
 535 /**
 536  * snd_ctl_activate_id - activate/inactivate the control of the given id
 537  * @card: the card instance
 538  * @id: the control id to activate/inactivate
 539  * @active: non-zero to activate
 540  *
 541  * Finds the control instance with the given id, and activate or
 542  * inactivate the control together with notification, if changed.
 543  *
 544  * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
 545  */
 546 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
 547                         int active)
 548 {
 549         struct snd_kcontrol *kctl;
 550         struct snd_kcontrol_volatile *vd;
 551         unsigned int index_offset;
 552         int ret;
 553
 554         down_write(&card->controls_rwsem);
 555         kctl = snd_ctl_find_id(card, id);
 556         if (kctl == NULL) {
 557                 ret = -ENOENT;
 558                 goto unlock;
 559         }
 560         index_offset = snd_ctl_get_ioff(kctl, &kctl->id);
 561         vd = &kctl->vd[index_offset];
 562         ret = 0;
 563         if (active) {
 564                 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
 565                         goto unlock;
 566                 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 567         } else {
 568                 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
 569                         goto unlock;
 570                 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 571         }
 572         ret = 1;
 573  unlock:
 574         up_write(&card->controls_rwsem);
 575         if (ret > 0)
 576                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
 577         return ret;
 578 }
 579 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
 580
 581 /**
 582  * snd_ctl_rename_id - replace the id of a control on the card
 583  * @card: the card instance
 584  * @src_id: the old id
 585  * @dst_id: the new id
 586  *
 587  * Finds the control with the old id from the card, and replaces the
 588  * id with the new one.
 589  *
 590  * Return: Zero if successful, or a negative error code on failure.
 591  */
 592 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 593                       struct snd_ctl_elem_id *dst_id)
 594 {
 595         struct snd_kcontrol *kctl;
 596
 597         down_write(&card->controls_rwsem);
 598         kctl = snd_ctl_find_id(card, src_id);
 599         if (kctl == NULL) {
 600                 up_write(&card->controls_rwsem);
 601                 return -ENOENT;
 602         }
 603         kctl->id = *dst_id;
 604         kctl->id.numid = card->last_numid + 1;
 605         card->last_numid += kctl->count;
 606         up_write(&card->controls_rwsem);
 607         return 0;
 608 }
 609
 610 EXPORT_SYMBOL(snd_ctl_rename_id);
 611
 612 /**
 613  * snd_ctl_find_numid - find the control instance with the given number-id
 614  * @card: the card instance
 615  * @numid: the number-id to search
 616  *
 617  * Finds the control instance with the given number-id from the card.
 618  *
 619  * The caller must down card->controls_rwsem before calling this function
 620  * (if the race condition can happen).
 621  *
 622  * Return: The pointer of the instance if found, or %NULL if not.
 623  *
 624  */
 625 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 626 {
 627         struct snd_kcontrol *kctl;
 628
 629         if (snd_BUG_ON(!card || !numid))
 630                 return NULL;
 631         list_for_each_entry(kctl, &card->controls, list) {
 632                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 633                         return kctl;
 634         }
 635         return NULL;
 636 }
 637
 638 EXPORT_SYMBOL(snd_ctl_find_numid);
 639
 640 /**
 641  * snd_ctl_find_id - find the control instance with the given id
 642  * @card: the card instance
 643  * @id: the id to search
 644  *
 645  * Finds the control instance with the given id from the card.
 646  *
 647  * The caller must down card->controls_rwsem before calling this function
 648  * (if the race condition can happen).
 649  *
 650  * Return: The pointer of the instance if found, or %NULL if not.
 651  *
 652  */
 653 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 654                                      struct snd_ctl_elem_id *id)
 655 {
 656         struct snd_kcontrol *kctl;
 657
 658         if (snd_BUG_ON(!card || !id))
 659                 return NULL;
 660         if (id->numid != 0)
 661                 return snd_ctl_find_numid(card, id->numid);
 662         list_for_each_entry(kctl, &card->controls, list) {
 663                 if (kctl->id.iface != id->iface)
 664                         continue;
 665                 if (kctl->id.device != id->device)
 666                         continue;
 667                 if (kctl->id.subdevice != id->subdevice)
 668                         continue;
 669                 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
 670                         continue;
 671                 if (kctl->id.index > id->index)
 672                         continue;
 673                 if (kctl->id.index + kctl->count <= id->index)
 674                         continue;
 675                 return kctl;
 676         }
 677         return NULL;
 678 }
 679
 680 EXPORT_SYMBOL(snd_ctl_find_id);
 681
 682 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 683                              unsigned int cmd, void __user *arg)
 684 {
 685         struct snd_ctl_card_info *info;
 686
 687         info = kzalloc(sizeof(*info), GFP_KERNEL);
 688         if (! info)
 689                 return -ENOMEM;
 690         down_read(&snd_ioctl_rwsem);
 691         info->card = card->number;
 692         strlcpy(info->id, card->id, sizeof(info->id));
 693         strlcpy(info->driver, card->driver, sizeof(info->driver));
 694         strlcpy(info->name, card->shortname, sizeof(info->name));
 695         strlcpy(info->longname, card->longname, sizeof(info->longname));
 696         strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
 697         strlcpy(info->components, card->components, sizeof(info->components));
 698         up_read(&snd_ioctl_rwsem);
 699         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 700                 kfree(info);
 701                 return -EFAULT;
 702         }
 703         kfree(info);
 704         return 0;
 705 }
 706
 707 static int snd_ctl_elem_list(struct snd_card *card,
 708                              struct snd_ctl_elem_list __user *_list)
 709 {
 710         struct list_head *plist;
 711         struct snd_ctl_elem_list list;
 712         struct snd_kcontrol *kctl;
 713         struct snd_ctl_elem_id *dst, *id;
 714         unsigned int offset, space, jidx;
 715
 716         if (copy_from_user(&list, _list, sizeof(list)))
 717                 return -EFAULT;
 718         offset = list.offset;
 719         space = list.space;
 720         /* try limit maximum space */
 721         if (space > 16384)
 722                 return -ENOMEM;
 723         if (space > 0) {
 724                 /* allocate temporary buffer for atomic operation */
 725                 dst = vmalloc(space * sizeof(struct snd_ctl_elem_id));
 726                 if (dst == NULL)
 727                         return -ENOMEM;
 728                 down_read(&card->controls_rwsem);
 729                 list.count = card->controls_count;
 730                 plist = card->controls.next;
 731                 while (plist != &card->controls) {
 732                         if (offset == 0)
 733                                 break;
 734                         kctl = snd_kcontrol(plist);
 735                         if (offset < kctl->count)
 736                                 break;
 737                         offset -= kctl->count;
 738                         plist = plist->next;
 739                 }
 740                 list.used = 0;
 741                 id = dst;
 742                 while (space > 0 && plist != &card->controls) {
 743                         kctl = snd_kcontrol(plist);
 744                         for (jidx = offset; space > 0 && jidx < kctl->count; jidx++) {
 745                                 snd_ctl_build_ioff(id, kctl, jidx);
 746                                 id++;
 747                                 space--;
 748                                 list.used++;
 749                         }
 750                         plist = plist->next;
 751                         offset = 0;
 752                 }
 753                 up_read(&card->controls_rwsem);
 754                 if (list.used > 0 &&
 755                     copy_to_user(list.pids, dst,
 756                                  list.used * sizeof(struct snd_ctl_elem_id))) {
 757                         vfree(dst);
 758                         return -EFAULT;
 759                 }
 760                 vfree(dst);
 761         } else {
 762                 down_read(&card->controls_rwsem);
 763                 list.count = card->controls_count;
 764                 up_read(&card->controls_rwsem);
 765         }
 766         if (copy_to_user(_list, &list, sizeof(list)))
 767                 return -EFAULT;
 768         return 0;
 769 }
 770
 771 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 772                              struct snd_ctl_elem_info *info)
 773 {
 774         struct snd_card *card = ctl->card;
 775         struct snd_kcontrol *kctl;
 776         struct snd_kcontrol_volatile *vd;
 777         unsigned int index_offset;
 778         int result;
 779
 780         down_read(&card->controls_rwsem);
 781         kctl = snd_ctl_find_id(card, &info->id);
 782         if (kctl == NULL) {
 783                 up_read(&card->controls_rwsem);
 784                 return -ENOENT;
 785         }
 786 #ifdef CONFIG_SND_DEBUG
 787         info->access = 0;
 788 #endif
 789         result = kctl->info(kctl, info);
 790         if (result >= 0) {
 791                 snd_BUG_ON(info->access);
 792                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
 793                 vd = &kctl->vd[index_offset];
 794                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
 795                 info->access = vd->access;
 796                 if (vd->owner) {
 797                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
 798                         if (vd->owner == ctl)
 799                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
 800                         info->owner = pid_vnr(vd->owner->pid);
 801                 } else {
 802                         info->owner = -1;
 803                 }
 804         }
 805         up_read(&card->controls_rwsem);
 806         return result;
 807 }
 808
 809 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
 810                                   struct snd_ctl_elem_info __user *_info)
 811 {
 812         struct snd_ctl_elem_info info;
 813         int result;
 814
 815         if (copy_from_user(&info, _info, sizeof(info)))
 816                 return -EFAULT;
 817         snd_power_lock(ctl->card);
 818         result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
 819         if (result >= 0)
 820                 result = snd_ctl_elem_info(ctl, &info);
 821         snd_power_unlock(ctl->card);
 822         if (result >= 0)
 823                 if (copy_to_user(_info, &info, sizeof(info)))
 824                         return -EFAULT;
 825         return result;
 826 }
 827
 828 static int snd_ctl_elem_read(struct snd_card *card,
 829                              struct snd_ctl_elem_value *control)
 830 {
 831         struct snd_kcontrol *kctl;
 832         struct snd_kcontrol_volatile *vd;
 833         unsigned int index_offset;
 834         int result;
 835
 836         down_read(&card->controls_rwsem);
 837         kctl = snd_ctl_find_id(card, &control->id);
 838         if (kctl == NULL) {
 839                 result = -ENOENT;
 840         } else {
 841                 index_offset = snd_ctl_get_ioff(kctl, &control->id);
 842                 vd = &kctl->vd[index_offset];
 843                 if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) &&
 844                     kctl->get != NULL) {
 845                         snd_ctl_build_ioff(&control->id, kctl, index_offset);
 846                         result = kctl->get(kctl, control);
 847                 } else
 848                         result = -EPERM;
 849         }
 850         up_read(&card->controls_rwsem);
 851         return result;
 852 }
 853
 854 static int snd_ctl_elem_read_user(struct snd_card *card,
 855                                   struct snd_ctl_elem_value __user *_control)
 856 {
 857         struct snd_ctl_elem_value *control;
 858         int result;
 859
 860         control = memdup_user(_control, sizeof(*control));
 861         if (IS_ERR(control))
 862                 return PTR_ERR(control);
 863
 864         snd_power_lock(card);
 865         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 866         if (result >= 0)
 867                 result = snd_ctl_elem_read(card, control);
 868         snd_power_unlock(card);
 869         if (result >= 0)
 870                 if (copy_to_user(_control, control, sizeof(*control)))
 871                         result = -EFAULT;
 872         kfree(control);
 873         return result;
 874 }
 875
 876 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
 877                               struct snd_ctl_elem_value *control)
 878 {
 879         struct snd_kcontrol *kctl;
 880         struct snd_kcontrol_volatile *vd;
 881         unsigned int index_offset;
 882         int result;
 883
 884         down_read(&card->controls_rwsem);
 885         kctl = snd_ctl_find_id(card, &control->id);
 886         if (kctl == NULL) {
 887                 result = -ENOENT;
 888         } else {
 889                 index_offset = snd_ctl_get_ioff(kctl, &control->id);
 890                 vd = &kctl->vd[index_offset];
 891                 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
 892                     kctl->put == NULL ||
 893                     (file && vd->owner && vd->owner != file)) {
 894                         result = -EPERM;
 895                 } else {
 896                         snd_ctl_build_ioff(&control->id, kctl, index_offset);
 897                         result = kctl->put(kctl, control);
 898                 }
 899                 if (result > 0) {
 900                         up_read(&card->controls_rwsem);
 901                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 902                                        &control->id);
 903                         return 0;
 904                 }
 905         }
 906         up_read(&card->controls_rwsem);
 907         return result;
 908 }
 909
 910 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
 911                                    struct snd_ctl_elem_value __user *_control)
 912 {
 913         struct snd_ctl_elem_value *control;
 914         struct snd_card *card;
 915         int result;
 916
 917         control = memdup_user(_control, sizeof(*control));
 918         if (IS_ERR(control))
 919                 return PTR_ERR(control);
 920
 921         card = file->card;
 922         snd_power_lock(card);
 923         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 924         if (result >= 0)
 925                 result = snd_ctl_elem_write(card, file, control);
 926         snd_power_unlock(card);
 927         if (result >= 0)
 928                 if (copy_to_user(_control, control, sizeof(*control)))
 929                         result = -EFAULT;
 930         kfree(control);
 931         return result;
 932 }
 933
 934 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
 935                              struct snd_ctl_elem_id __user *_id)
 936 {
 937         struct snd_card *card = file->card;
 938         struct snd_ctl_elem_id id;
 939         struct snd_kcontrol *kctl;
 940         struct snd_kcontrol_volatile *vd;
 941         int result;
 942
 943         if (copy_from_user(&id, _id, sizeof(id)))
 944                 return -EFAULT;
 945         down_write(&card->controls_rwsem);
 946         kctl = snd_ctl_find_id(card, &id);
 947         if (kctl == NULL) {
 948                 result = -ENOENT;
 949         } else {
 950                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
 951                 if (vd->owner != NULL)
 952                         result = -EBUSY;
 953                 else {
 954                         vd->owner = file;
 955                         result = 0;
 956                 }
 957         }
 958         up_write(&card->controls_rwsem);
 959         return result;
 960 }
 961
 962 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
 963                                struct snd_ctl_elem_id __user *_id)
 964 {
 965         struct snd_card *card = file->card;
 966         struct snd_ctl_elem_id id;
 967         struct snd_kcontrol *kctl;
 968         struct snd_kcontrol_volatile *vd;
 969         int result;
 970
 971         if (copy_from_user(&id, _id, sizeof(id)))
 972                 return -EFAULT;
 973         down_write(&card->controls_rwsem);
 974         kctl = snd_ctl_find_id(card, &id);
 975         if (kctl == NULL) {
 976                 result = -ENOENT;
 977         } else {
 978                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
 979                 if (vd->owner == NULL)
 980                         result = -EINVAL;
 981                 else if (vd->owner != file)
 982                         result = -EPERM;
 983                 else {
 984                         vd->owner = NULL;
 985                         result = 0;
 986                 }
 987         }
 988         up_write(&card->controls_rwsem);
 989         return result;
 990 }
 991
 992 struct user_element {
 993         struct snd_ctl_elem_info info;
 994         void *elem_data;                /* element data */
 995         unsigned long elem_data_size;   /* size of element data in bytes */
 996         void *tlv_data;                 /* TLV data */
 997         unsigned long tlv_data_size;    /* TLV data size */
 998         void *priv_data;                /* private data (like strings for enumerated type) */
 999 };
1000
1001 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1002                                   struct snd_ctl_elem_info *uinfo)
1003 {
1004         struct user_element *ue = kcontrol->private_data;
1005
1006         *uinfo = ue->info;
1007         return 0;
1008 }
1009
1010 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1011                                        struct snd_ctl_elem_info *uinfo)
1012 {
1013         struct user_element *ue = kcontrol->private_data;
1014         const char *names;
1015         unsigned int item;
1016
1017         item = uinfo->value.enumerated.item;
1018
1019         *uinfo = ue->info;
1020
1021         item = min(item, uinfo->value.enumerated.items - 1);
1022         uinfo->value.enumerated.item = item;
1023
1024         names = ue->priv_data;
1025         for (; item > 0; --item)
1026                 names += strlen(names) + 1;
1027         strcpy(uinfo->value.enumerated.name, names);
1028
1029         return 0;
1030 }
1031
1032 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1033                                  struct snd_ctl_elem_value *ucontrol)
1034 {
1035         struct user_element *ue = kcontrol->private_data;
1036
1037         memcpy(&ucontrol->value, ue->elem_data, ue->elem_data_size);
1038         return 0;
1039 }
1040
1041 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1042                                  struct snd_ctl_elem_value *ucontrol)
1043 {
1044         int change;
1045         struct user_element *ue = kcontrol->private_data;
1046
1047         change = memcmp(&ucontrol->value, ue->elem_data, ue->elem_data_size) != 0;
1048         if (change)
1049                 memcpy(ue->elem_data, &ucontrol->value, ue->elem_data_size);
1050         return change;
1051 }
1052
1053 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol,
1054                                  int op_flag,
1055                                  unsigned int size,
1056                                  unsigned int __user *tlv)
1057 {
1058         struct user_element *ue = kcontrol->private_data;
1059         int change = 0;
1060         void *new_data;
1061
1062         if (op_flag > 0) {
1063                 if (size > 1024 * 128)  /* sane value */
1064                         return -EINVAL;
1065
1066                 new_data = memdup_user(tlv, size);
1067                 if (IS_ERR(new_data))
1068                         return PTR_ERR(new_data);
1069                 change = ue->tlv_data_size != size;
1070                 if (!change)
1071                         change = memcmp(ue->tlv_data, new_data, size);
1072                 kfree(ue->tlv_data);
1073                 ue->tlv_data = new_data;
1074                 ue->tlv_data_size = size;
1075         } else {
1076                 if (! ue->tlv_data_size || ! ue->tlv_data)
1077                         return -ENXIO;
1078                 if (size < ue->tlv_data_size)
1079                         return -ENOSPC;
1080                 if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size))
1081                         return -EFAULT;
1082         }
1083         return change;
1084 }
1085
1086 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1087 {
1088         char *names, *p;
1089         size_t buf_len, name_len;
1090         unsigned int i;
1091         const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1092
1093         if (ue->info.value.enumerated.names_length > 64 * 1024)
1094                 return -EINVAL;
1095
1096         names = memdup_user((const void __user *)user_ptrval,
1097                 ue->info.value.enumerated.names_length);
1098         if (IS_ERR(names))
1099                 return PTR_ERR(names);
1100
1101         /* check that there are enough valid names */
1102         buf_len = ue->info.value.enumerated.names_length;
1103         p = names;
1104         for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1105                 name_len = strnlen(p, buf_len);
1106                 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1107                         kfree(names);
1108                         return -EINVAL;
1109                 }
1110                 p += name_len + 1;
1111                 buf_len -= name_len + 1;
1112         }
1113
1114         ue->priv_data = names;
1115         ue->info.value.enumerated.names_ptr = 0;
1116
1117         return 0;
1118 }
1119
1120 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1121 {
1122         struct user_element *ue = kcontrol->private_data;
1123
1124         kfree(ue->tlv_data);
1125         kfree(ue->priv_data);
1126         kfree(ue);
1127 }
1128
1129 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1130                             struct snd_ctl_elem_info *info, int replace)
1131 {
1132         struct snd_card *card = file->card;
1133         struct snd_kcontrol kctl, *_kctl;
1134         unsigned int access;
1135         long private_size;
1136         struct user_element *ue;
1137         int idx, err;
1138
1139         if (!replace && card->user_ctl_count >= MAX_USER_CONTROLS)
1140                 return -ENOMEM;
1141         if (info->count < 1)
1142                 return -EINVAL;
1143         access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
1144                 (info->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
1145                                  SNDRV_CTL_ELEM_ACCESS_INACTIVE|
1146                                  SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE));
1147         info->id.numid = 0;
1148         memset(&kctl, 0, sizeof(kctl));
1149         down_write(&card->controls_rwsem);
1150         _kctl = snd_ctl_find_id(card, &info->id);
1151         err = 0;
1152         if (_kctl) {
1153                 if (replace)
1154                         err = snd_ctl_remove(card, _kctl);
1155                 else
1156                         err = -EBUSY;
1157         } else {
1158                 if (replace)
1159                         err = -ENOENT;
1160         }
1161         up_write(&card->controls_rwsem);
1162         if (err < 0)
1163                 return err;
1164         memcpy(&kctl.id, &info->id, sizeof(info->id));
1165         kctl.count = info->owner ? info->owner : 1;
1166         access |= SNDRV_CTL_ELEM_ACCESS_USER;
1167         if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1168                 kctl.info = snd_ctl_elem_user_enum_info;
1169         else
1170                 kctl.info = snd_ctl_elem_user_info;
1171         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1172                 kctl.get = snd_ctl_elem_user_get;
1173         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1174                 kctl.put = snd_ctl_elem_user_put;
1175         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE) {
1176                 kctl.tlv.c = snd_ctl_elem_user_tlv;
1177                 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1178         }
1179         switch (info->type) {
1180         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
1181         case SNDRV_CTL_ELEM_TYPE_INTEGER:
1182                 private_size = sizeof(long);
1183                 if (info->count > 128)
1184                         return -EINVAL;
1185                 break;
1186         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1187                 private_size = sizeof(long long);
1188                 if (info->count > 64)
1189                         return -EINVAL;
1190                 break;
1191         case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
1192                 private_size = sizeof(unsigned int);
1193                 if (info->count > 128 || info->value.enumerated.items == 0)
1194                         return -EINVAL;
1195                 break;
1196         case SNDRV_CTL_ELEM_TYPE_BYTES:
1197                 private_size = sizeof(unsigned char);
1198                 if (info->count > 512)
1199                         return -EINVAL;
1200                 break;
1201         case SNDRV_CTL_ELEM_TYPE_IEC958:
1202                 private_size = sizeof(struct snd_aes_iec958);
1203                 if (info->count != 1)
1204                         return -EINVAL;
1205                 break;
1206         default:
1207                 return -EINVAL;
1208         }
1209         private_size *= info->count;
1210         ue = kzalloc(sizeof(struct user_element) + private_size, GFP_KERNEL);
1211         if (ue == NULL)
1212                 return -ENOMEM;
1213         ue->info = *info;
1214         ue->info.access = 0;
1215         ue->elem_data = (char *)ue + sizeof(*ue);
1216         ue->elem_data_size = private_size;
1217         if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1218                 err = snd_ctl_elem_init_enum_names(ue);
1219                 if (err < 0) {
1220                         kfree(ue);
1221                         return err;
1222                 }
1223         }
1224         kctl.private_free = snd_ctl_elem_user_free;
1225         _kctl = snd_ctl_new(&kctl, access);
1226         if (_kctl == NULL) {
1227                 kfree(ue->priv_data);
1228                 kfree(ue);
1229                 return -ENOMEM;
1230         }
1231         _kctl->private_data = ue;
1232         for (idx = 0; idx < _kctl->count; idx++)
1233                 _kctl->vd[idx].owner = file;
1234         err = snd_ctl_add(card, _kctl);
1235         if (err < 0)
1236                 return err;
1237
1238         down_write(&card->controls_rwsem);
1239         card->user_ctl_count++;
1240         up_write(&card->controls_rwsem);
1241
1242         return 0;
1243 }
1244
1245 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1246                                  struct snd_ctl_elem_info __user *_info, int replace)
1247 {
1248         struct snd_ctl_elem_info info;
1249         if (copy_from_user(&info, _info, sizeof(info)))
1250                 return -EFAULT;
1251         return snd_ctl_elem_add(file, &info, replace);
1252 }
1253
1254 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1255                                struct snd_ctl_elem_id __user *_id)
1256 {
1257         struct snd_ctl_elem_id id;
1258
1259         if (copy_from_user(&id, _id, sizeof(id)))
1260                 return -EFAULT;
1261         return snd_ctl_remove_user_ctl(file, &id);
1262 }
1263
1264 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1265 {
1266         int subscribe;
1267         if (get_user(subscribe, ptr))
1268                 return -EFAULT;
1269         if (subscribe < 0) {
1270                 subscribe = file->subscribed;
1271                 if (put_user(subscribe, ptr))
1272                         return -EFAULT;
1273                 return 0;
1274         }
1275         if (subscribe) {
1276                 file->subscribed = 1;
1277                 return 0;
1278         } else if (file->subscribed) {
1279                 snd_ctl_empty_read_queue(file);
1280                 file->subscribed = 0;
1281         }
1282         return 0;
1283 }
1284
1285 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1286                              struct snd_ctl_tlv __user *_tlv,
1287                              int op_flag)
1288 {
1289         struct snd_card *card = file->card;
1290         struct snd_ctl_tlv tlv;
1291         struct snd_kcontrol *kctl;
1292         struct snd_kcontrol_volatile *vd;
1293         unsigned int len;
1294         int err = 0;
1295
1296         if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
1297                 return -EFAULT;
1298         if (tlv.length < sizeof(unsigned int) * 2)
1299                 return -EINVAL;
1300         down_read(&card->controls_rwsem);
1301         kctl = snd_ctl_find_numid(card, tlv.numid);
1302         if (kctl == NULL) {
1303                 err = -ENOENT;
1304                 goto __kctl_end;
1305         }
1306         if (kctl->tlv.p == NULL) {
1307                 err = -ENXIO;
1308                 goto __kctl_end;
1309         }
1310         vd = &kctl->vd[tlv.numid - kctl->id.numid];
1311         if ((op_flag == 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||
1312             (op_flag > 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||
1313             (op_flag < 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0)) {
1314                 err = -ENXIO;
1315                 goto __kctl_end;
1316         }
1317         if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1318                 if (vd->owner != NULL && vd->owner != file) {
1319                         err = -EPERM;
1320                         goto __kctl_end;
1321                 }
1322                 err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv);
1323                 if (err > 0) {
1324                         up_read(&card->controls_rwsem);
1325                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &kctl->id);
1326                         return 0;
1327                 }
1328         } else {
1329                 if (op_flag) {
1330                         err = -ENXIO;
1331                         goto __kctl_end;
1332                 }
1333                 len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);
1334                 if (tlv.length < len) {
1335                         err = -ENOMEM;
1336                         goto __kctl_end;
1337                 }
1338                 if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))
1339                         err = -EFAULT;
1340         }
1341       __kctl_end:
1342         up_read(&card->controls_rwsem);
1343         return err;
1344 }
1345
1346 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1347 {
1348         struct snd_ctl_file *ctl;
1349         struct snd_card *card;
1350         struct snd_kctl_ioctl *p;
1351         void __user *argp = (void __user *)arg;
1352         int __user *ip = argp;
1353         int err;
1354
1355         ctl = file->private_data;
1356         card = ctl->card;
1357         if (snd_BUG_ON(!card))
1358                 return -ENXIO;
1359         switch (cmd) {
1360         case SNDRV_CTL_IOCTL_PVERSION:
1361                 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1362         case SNDRV_CTL_IOCTL_CARD_INFO:
1363                 return snd_ctl_card_info(card, ctl, cmd, argp);
1364         case SNDRV_CTL_IOCTL_ELEM_LIST:
1365                 return snd_ctl_elem_list(card, argp);
1366         case SNDRV_CTL_IOCTL_ELEM_INFO:
1367                 return snd_ctl_elem_info_user(ctl, argp);
1368         case SNDRV_CTL_IOCTL_ELEM_READ:
1369                 return snd_ctl_elem_read_user(card, argp);
1370         case SNDRV_CTL_IOCTL_ELEM_WRITE:
1371                 return snd_ctl_elem_write_user(ctl, argp);
1372         case SNDRV_CTL_IOCTL_ELEM_LOCK:
1373                 return snd_ctl_elem_lock(ctl, argp);
1374         case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1375                 return snd_ctl_elem_unlock(ctl, argp);
1376         case SNDRV_CTL_IOCTL_ELEM_ADD:
1377                 return snd_ctl_elem_add_user(ctl, argp, 0);
1378         case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1379                 return snd_ctl_elem_add_user(ctl, argp, 1);
1380         case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1381                 return snd_ctl_elem_remove(ctl, argp);
1382         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1383                 return snd_ctl_subscribe_events(ctl, ip);
1384         case SNDRV_CTL_IOCTL_TLV_READ:
1385                 return snd_ctl_tlv_ioctl(ctl, argp, 0);
1386         case SNDRV_CTL_IOCTL_TLV_WRITE:
1387                 return snd_ctl_tlv_ioctl(ctl, argp, 1);
1388         case SNDRV_CTL_IOCTL_TLV_COMMAND:
1389                 return snd_ctl_tlv_ioctl(ctl, argp, -1);
1390         case SNDRV_CTL_IOCTL_POWER:
1391                 return -ENOPROTOOPT;
1392         case SNDRV_CTL_IOCTL_POWER_STATE:
1393 #ifdef CONFIG_PM
1394                 return put_user(card->power_state, ip) ? -EFAULT : 0;
1395 #else
1396                 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1397 #endif
1398         }
1399         down_read(&snd_ioctl_rwsem);
1400         list_for_each_entry(p, &snd_control_ioctls, list) {
1401                 err = p->fioctl(card, ctl, cmd, arg);
1402                 if (err != -ENOIOCTLCMD) {
1403                         up_read(&snd_ioctl_rwsem);
1404                         return err;
1405                 }
1406         }
1407         up_read(&snd_ioctl_rwsem);
1408         dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
1409         return -ENOTTY;
1410 }
1411
1412 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1413                             size_t count, loff_t * offset)
1414 {
1415         struct snd_ctl_file *ctl;
1416         int err = 0;
1417         ssize_t result = 0;
1418
1419         ctl = file->private_data;
1420         if (snd_BUG_ON(!ctl || !ctl->card))
1421                 return -ENXIO;
1422         if (!ctl->subscribed)
1423                 return -EBADFD;
1424         if (count < sizeof(struct snd_ctl_event))
1425                 return -EINVAL;
1426         spin_lock_irq(&ctl->read_lock);
1427         while (count >= sizeof(struct snd_ctl_event)) {
1428                 struct snd_ctl_event ev;
1429                 struct snd_kctl_event *kev;
1430                 while (list_empty(&ctl->events)) {
1431                         wait_queue_t wait;
1432                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1433                                 err = -EAGAIN;
1434                                 goto __end_lock;
1435                         }
1436                         init_waitqueue_entry(&wait, current);
1437                         add_wait_queue(&ctl->change_sleep, &wait);
1438                         set_current_state(TASK_INTERRUPTIBLE);
1439                         spin_unlock_irq(&ctl->read_lock);
1440                         schedule();
1441                         remove_wait_queue(&ctl->change_sleep, &wait);
1442                         if (ctl->card->shutdown)
1443                                 return -ENODEV;
1444                         if (signal_pending(current))
1445                                 return -ERESTARTSYS;
1446                         spin_lock_irq(&ctl->read_lock);
1447                 }
1448                 kev = snd_kctl_event(ctl->events.next);
1449                 ev.type = SNDRV_CTL_EVENT_ELEM;
1450                 ev.data.elem.mask = kev->mask;
1451                 ev.data.elem.id = kev->id;
1452                 list_del(&kev->list);
1453                 spin_unlock_irq(&ctl->read_lock);
1454                 kfree(kev);
1455                 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1456                         err = -EFAULT;
1457                         goto __end;
1458                 }
1459                 spin_lock_irq(&ctl->read_lock);
1460                 buffer += sizeof(struct snd_ctl_event);
1461                 count -= sizeof(struct snd_ctl_event);
1462                 result += sizeof(struct snd_ctl_event);
1463         }
1464       __end_lock:
1465         spin_unlock_irq(&ctl->read_lock);
1466       __end:
1467         return result > 0 ? result : err;
1468 }
1469
1470 static unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
1471 {
1472         unsigned int mask;
1473         struct snd_ctl_file *ctl;
1474
1475         ctl = file->private_data;
1476         if (!ctl->subscribed)
1477                 return 0;
1478         poll_wait(file, &ctl->change_sleep, wait);
1479
1480         mask = 0;
1481         if (!list_empty(&ctl->events))
1482                 mask |= POLLIN | POLLRDNORM;
1483
1484         return mask;
1485 }
1486
1487 /*
1488  * register the device-specific control-ioctls.
1489  * called from each device manager like pcm.c, hwdep.c, etc.
1490  */
1491 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1492 {
1493         struct snd_kctl_ioctl *pn;
1494
1495         pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1496         if (pn == NULL)
1497                 return -ENOMEM;
1498         pn->fioctl = fcn;
1499         down_write(&snd_ioctl_rwsem);
1500         list_add_tail(&pn->list, lists);
1501         up_write(&snd_ioctl_rwsem);
1502         return 0;
1503 }
1504
1505 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1506 {
1507         return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1508 }
1509
1510 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1511
1512 #ifdef CONFIG_COMPAT
1513 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1514 {
1515         return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1516 }
1517
1518 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1519 #endif
1520
1521 /*
1522  * de-register the device-specific control-ioctls.
1523  */
1524 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1525                                      struct list_head *lists)
1526 {
1527         struct snd_kctl_ioctl *p;
1528
1529         if (snd_BUG_ON(!fcn))
1530                 return -EINVAL;
1531         down_write(&snd_ioctl_rwsem);
1532         list_for_each_entry(p, lists, list) {
1533                 if (p->fioctl == fcn) {
1534                         list_del(&p->list);
1535                         up_write(&snd_ioctl_rwsem);
1536                         kfree(p);
1537                         return 0;
1538                 }
1539         }
1540         up_write(&snd_ioctl_rwsem);
1541         snd_BUG();
1542         return -EINVAL;
1543 }
1544
1545 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1546 {
1547         return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1548 }
1549
1550 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1551
1552 #ifdef CONFIG_COMPAT
1553 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1554 {
1555         return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1556 }
1557
1558 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1559 #endif
1560
1561 static int snd_ctl_fasync(int fd, struct file * file, int on)
1562 {
1563         struct snd_ctl_file *ctl;
1564
1565         ctl = file->private_data;
1566         return fasync_helper(fd, file, on, &ctl->fasync);
1567 }
1568
1569 /*
1570  * ioctl32 compat
1571  */
1572 #ifdef CONFIG_COMPAT
1573 #include "control_compat.c"
1574 #else
1575 #define snd_ctl_ioctl_compat    NULL
1576 #endif
1577
1578 /*
1579  *  INIT PART
1580  */
1581
1582 static const struct file_operations snd_ctl_f_ops =
1583 {
1584         .owner =        THIS_MODULE,
1585         .read =         snd_ctl_read,
1586         .open =         snd_ctl_open,
1587         .release =      snd_ctl_release,
1588         .llseek =       no_llseek,
1589         .poll =         snd_ctl_poll,
1590         .unlocked_ioctl =       snd_ctl_ioctl,
1591         .compat_ioctl = snd_ctl_ioctl_compat,
1592         .fasync =       snd_ctl_fasync,
1593 };
1594
1595 /*
1596  * registration of the control device
1597  */
1598 static int snd_ctl_dev_register(struct snd_device *device)
1599 {
1600         struct snd_card *card = device->device_data;
1601         int err, cardnum;
1602         char name[16];
1603
1604         if (snd_BUG_ON(!card))
1605                 return -ENXIO;
1606         cardnum = card->number;
1607         if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
1608                 return -ENXIO;
1609         sprintf(name, "controlC%i", cardnum);
1610         if ((err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
1611                                        &snd_ctl_f_ops, card, name)) < 0)
1612                 return err;
1613         return 0;
1614 }
1615
1616 /*
1617  * disconnection of the control device
1618  */
1619 static int snd_ctl_dev_disconnect(struct snd_device *device)
1620 {
1621         struct snd_card *card = device->device_data;
1622         struct snd_ctl_file *ctl;
1623         int err, cardnum;
1624
1625         if (snd_BUG_ON(!card))
1626                 return -ENXIO;
1627         cardnum = card->number;
1628         if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
1629                 return -ENXIO;
1630
1631         read_lock(&card->ctl_files_rwlock);
1632         list_for_each_entry(ctl, &card->ctl_files, list) {
1633                 wake_up(&ctl->change_sleep);
1634                 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1635         }
1636         read_unlock(&card->ctl_files_rwlock);
1637
1638         if ((err = snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL,
1639                                          card, -1)) < 0)
1640                 return err;
1641         return 0;
1642 }
1643
1644 /*
1645  * free all controls
1646  */
1647 static int snd_ctl_dev_free(struct snd_device *device)
1648 {
1649         struct snd_card *card = device->device_data;
1650         struct snd_kcontrol *control;
1651
1652         down_write(&card->controls_rwsem);
1653         while (!list_empty(&card->controls)) {
1654                 control = snd_kcontrol(card->controls.next);
1655                 snd_ctl_remove(card, control);
1656         }
1657         up_write(&card->controls_rwsem);
1658         return 0;
1659 }
1660
1661 /*
1662  * create control core:
1663  * called from init.c
1664  */
1665 int snd_ctl_create(struct snd_card *card)
1666 {
1667         static struct snd_device_ops ops = {
1668                 .dev_free = snd_ctl_dev_free,
1669                 .dev_register = snd_ctl_dev_register,
1670                 .dev_disconnect = snd_ctl_dev_disconnect,
1671         };
1672
1673         if (snd_BUG_ON(!card))
1674                 return -ENXIO;
1675         return snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1676 }
1677
1678 /*
1679  * Frequently used control callbacks/helpers
1680  */
1681 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
1682                               struct snd_ctl_elem_info *uinfo)
1683 {
1684         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1685         uinfo->count = 1;
1686         uinfo->value.integer.min = 0;
1687         uinfo->value.integer.max = 1;
1688         return 0;
1689 }
1690
1691 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
1692
1693 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
1694                                 struct snd_ctl_elem_info *uinfo)
1695 {
1696         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1697         uinfo->count = 2;
1698         uinfo->value.integer.min = 0;
1699         uinfo->value.integer.max = 1;
1700         return 0;
1701 }
1702
1703 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
1704
1705 /**
1706  * snd_ctl_enum_info - fills the info structure for an enumerated control
1707  * @info: the structure to be filled
1708  * @channels: the number of the control's channels; often one
1709  * @items: the number of control values; also the size of @names
1710  * @names: an array containing the names of all control values
1711  *
1712  * Sets all required fields in @info to their appropriate values.
1713  * If the control's accessibility is not the default (readable and writable),
1714  * the caller has to fill @info->access.
1715  *
1716  * Return: Zero.
1717  */
1718 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
1719                       unsigned int items, const char *const names[])
1720 {
1721         info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
1722         info->count = channels;
1723         info->value.enumerated.items = items;
1724         if (info->value.enumerated.item >= items)
1725                 info->value.enumerated.item = items - 1;
1726         strlcpy(info->value.enumerated.name,
1727                 names[info->value.enumerated.item],
1728                 sizeof(info->value.enumerated.name));
1729         return 0;
1730 }
1731 EXPORT_SYMBOL(snd_ctl_enum_info);