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 <sound/driver.h>
  23 #include <linux/threads.h>
  24 #include <linux/interrupt.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
  36 struct snd_kctl_ioctl {
  37         struct list_head list;          /* list of all ioctls */
  38         snd_kctl_ioctl_func_t fioctl;
  39 };
  40
  41 static DECLARE_RWSEM(snd_ioctl_rwsem);
  42 static LIST_HEAD(snd_control_ioctls);
  43 #ifdef CONFIG_COMPAT
  44 static LIST_HEAD(snd_control_compat_ioctls);
  45 #endif
  46
  47 static int snd_ctl_open(struct inode *inode, struct file *file)
  48 {
  49         unsigned long flags;
  50         struct snd_card *card;
  51         struct snd_ctl_file *ctl;
  52         int err;
  53
  54         card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
  55         if (!card) {
  56                 err = -ENODEV;
  57                 goto __error1;
  58         }
  59         err = snd_card_file_add(card, file);
  60         if (err < 0) {
  61                 err = -ENODEV;
  62                 goto __error1;
  63         }
  64         if (!try_module_get(card->module)) {
  65                 err = -EFAULT;
  66                 goto __error2;
  67         }
  68         ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
  69         if (ctl == NULL) {
  70                 err = -ENOMEM;
  71                 goto __error;
  72         }
  73         INIT_LIST_HEAD(&ctl->events);
  74         init_waitqueue_head(&ctl->change_sleep);
  75         spin_lock_init(&ctl->read_lock);
  76         ctl->card = card;
  77         ctl->prefer_pcm_subdevice = -1;
  78         ctl->prefer_rawmidi_subdevice = -1;
  79         ctl->pid = current->pid;
  80         file->private_data = ctl;
  81         write_lock_irqsave(&card->ctl_files_rwlock, flags);
  82         list_add_tail(&ctl->list, &card->ctl_files);
  83         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
  84         return 0;
  85
  86       __error:
  87         module_put(card->module);
  88       __error2:
  89         snd_card_file_remove(card, file);
  90       __error1:
  91         return err;
  92 }
  93
  94 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
  95 {
  96         struct snd_kctl_event *cread;
  97
  98         spin_lock(&ctl->read_lock);
  99         while (!list_empty(&ctl->events)) {
 100                 cread = snd_kctl_event(ctl->events.next);
 101                 list_del(&cread->list);
 102                 kfree(cread);
 103         }
 104         spin_unlock(&ctl->read_lock);
 105 }
 106
 107 static int snd_ctl_release(struct inode *inode, struct file *file)
 108 {
 109         unsigned long flags;
 110         struct snd_card *card;
 111         struct snd_ctl_file *ctl;
 112         struct snd_kcontrol *control;
 113         unsigned int idx;
 114
 115         ctl = file->private_data;
 116         fasync_helper(-1, file, 0, &ctl->fasync);
 117         file->private_data = NULL;
 118         card = ctl->card;
 119         write_lock_irqsave(&card->ctl_files_rwlock, flags);
 120         list_del(&ctl->list);
 121         write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 122         down_write(&card->controls_rwsem);
 123         list_for_each_entry(control, &card->controls, list)
 124                 for (idx = 0; idx < control->count; idx++)
 125                         if (control->vd[idx].owner == ctl)
 126                                 control->vd[idx].owner = NULL;
 127         up_write(&card->controls_rwsem);
 128         snd_ctl_empty_read_queue(ctl);
 129         kfree(ctl);
 130         module_put(card->module);
 131         snd_card_file_remove(card, file);
 132         return 0;
 133 }
 134
 135 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 136                     struct snd_ctl_elem_id *id)
 137 {
 138         unsigned long flags;
 139         struct snd_ctl_file *ctl;
 140         struct snd_kctl_event *ev;
 141
 142         snd_assert(card != NULL && id != NULL, return);
 143         read_lock(&card->ctl_files_rwlock);
 144 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
 145         card->mixer_oss_change_count++;
 146 #endif
 147         list_for_each_entry(ctl, &card->ctl_files, list) {
 148                 if (!ctl->subscribed)
 149                         continue;
 150                 spin_lock_irqsave(&ctl->read_lock, flags);
 151                 list_for_each_entry(ev, &ctl->events, list) {
 152                         if (ev->id.numid == id->numid) {
 153                                 ev->mask |= mask;
 154                                 goto _found;
 155                         }
 156                 }
 157                 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
 158                 if (ev) {
 159                         ev->id = *id;
 160                         ev->mask = mask;
 161                         list_add_tail(&ev->list, &ctl->events);
 162                 } else {
 163                         snd_printk(KERN_ERR "No memory available to allocate event\n");
 164                 }
 165         _found:
 166                 wake_up(&ctl->change_sleep);
 167                 spin_unlock_irqrestore(&ctl->read_lock, flags);
 168                 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
 169         }
 170         read_unlock(&card->ctl_files_rwlock);
 171 }
 172
 173 EXPORT_SYMBOL(snd_ctl_notify);
 174
 175 /**
 176  * snd_ctl_new - create a control instance from the template
 177  * @control: the control template
 178  * @access: the default control access
 179  *
 180  * Allocates a new struct snd_kcontrol instance and copies the given template
 181  * to the new instance. It does not copy volatile data (access).
 182  *
 183  * Returns the pointer of the new instance, or NULL on failure.
 184  */
 185 static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control,
 186                                         unsigned int access)
 187 {
 188         struct snd_kcontrol *kctl;
 189         unsigned int idx;
 190
 191         snd_assert(control != NULL, return NULL);
 192         snd_assert(control->count > 0, return NULL);
 193         kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL);
 194         if (kctl == NULL) {
 195                 snd_printk(KERN_ERR "Cannot allocate control instance\n");
 196                 return NULL;
 197         }
 198         *kctl = *control;
 199         for (idx = 0; idx < kctl->count; idx++)
 200                 kctl->vd[idx].access = access;
 201         return kctl;
 202 }
 203
 204 /**
 205  * snd_ctl_new1 - create a control instance from the template
 206  * @ncontrol: the initialization record
 207  * @private_data: the private data to set
 208  *
 209  * Allocates a new struct snd_kcontrol instance and initialize from the given
 210  * template.  When the access field of ncontrol is 0, it's assumed as
 211  * READWRITE access. When the count field is 0, it's assumes as one.
 212  *
 213  * Returns the pointer of the newly generated instance, or NULL on failure.
 214  */
 215 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
 216                                   void *private_data)
 217 {
 218         struct snd_kcontrol kctl;
 219         unsigned int access;
 220
 221         snd_assert(ncontrol != NULL, return NULL);
 222         snd_assert(ncontrol->info != NULL, return NULL);
 223         memset(&kctl, 0, sizeof(kctl));
 224         kctl.id.iface = ncontrol->iface;
 225         kctl.id.device = ncontrol->device;
 226         kctl.id.subdevice = ncontrol->subdevice;
 227         if (ncontrol->name)
 228                 strlcpy(kctl.id.name, ncontrol->name, sizeof(kctl.id.name));
 229         kctl.id.index = ncontrol->index;
 230         kctl.count = ncontrol->count ? ncontrol->count : 1;
 231         access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
 232                  (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
 233                                       SNDRV_CTL_ELEM_ACCESS_INACTIVE|
 234                                       SNDRV_CTL_ELEM_ACCESS_DINDIRECT|
 235                                       SNDRV_CTL_ELEM_ACCESS_INDIRECT|
 236                                       SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE|
 237                                       SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK));
 238         kctl.info = ncontrol->info;
 239         kctl.get = ncontrol->get;
 240         kctl.put = ncontrol->put;
 241         kctl.tlv.p = ncontrol->tlv.p;
 242         kctl.private_value = ncontrol->private_value;
 243         kctl.private_data = private_data;
 244         return snd_ctl_new(&kctl, access);
 245 }
 246
 247 EXPORT_SYMBOL(snd_ctl_new1);
 248
 249 /**
 250  * snd_ctl_free_one - release the control instance
 251  * @kcontrol: the control instance
 252  *
 253  * Releases the control instance created via snd_ctl_new()
 254  * or snd_ctl_new1().
 255  * Don't call this after the control was added to the card.
 256  */
 257 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
 258 {
 259         if (kcontrol) {
 260                 if (kcontrol->private_free)
 261                         kcontrol->private_free(kcontrol);
 262                 kfree(kcontrol);
 263         }
 264 }
 265
 266 EXPORT_SYMBOL(snd_ctl_free_one);
 267
 268 static unsigned int snd_ctl_hole_check(struct snd_card *card,
 269                                        unsigned int count)
 270 {
 271         struct snd_kcontrol *kctl;
 272
 273         list_for_each_entry(kctl, &card->controls, list) {
 274                 if ((kctl->id.numid <= card->last_numid &&
 275                      kctl->id.numid + kctl->count > card->last_numid) ||
 276                     (kctl->id.numid <= card->last_numid + count - 1 &&
 277                      kctl->id.numid + kctl->count > card->last_numid + count - 1))
 278                         return card->last_numid = kctl->id.numid + kctl->count - 1;
 279         }
 280         return card->last_numid;
 281 }
 282
 283 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 284 {
 285         unsigned int last_numid, iter = 100000;
 286
 287         last_numid = card->last_numid;
 288         while (last_numid != snd_ctl_hole_check(card, count)) {
 289                 if (--iter == 0) {
 290                         /* this situation is very unlikely */
 291                         snd_printk(KERN_ERR "unable to allocate new control numid\n");
 292                         return -ENOMEM;
 293                 }
 294                 last_numid = card->last_numid;
 295         }
 296         return 0;
 297 }
 298
 299 /**
 300  * snd_ctl_add - add the control instance to the card
 301  * @card: the card instance
 302  * @kcontrol: the control instance to add
 303  *
 304  * Adds the control instance created via snd_ctl_new() or
 305  * snd_ctl_new1() to the given card. Assigns also an unique
 306  * numid used for fast search.
 307  *
 308  * Returns zero if successful, or a negative error code on failure.
 309  *
 310  * It frees automatically the control which cannot be added.
 311  */
 312 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 313 {
 314         struct snd_ctl_elem_id id;
 315         unsigned int idx;
 316         int err = -EINVAL;
 317
 318         if (! kcontrol)
 319                 return err;
 320         snd_assert(card != NULL, goto error);
 321         snd_assert(kcontrol->info != NULL, goto error);
 322         id = kcontrol->id;
 323         down_write(&card->controls_rwsem);
 324         if (snd_ctl_find_id(card, &id)) {
 325                 up_write(&card->controls_rwsem);
 326                 snd_printd(KERN_ERR "control %i:%i:%i:%s:%i is already present\n",
 327                                         id.iface,
 328                                         id.device,
 329                                         id.subdevice,
 330                                         id.name,
 331                                         id.index);
 332                 err = -EBUSY;
 333                 goto error;
 334         }
 335         if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 336                 up_write(&card->controls_rwsem);
 337                 err = -ENOMEM;
 338                 goto error;
 339         }
 340         list_add_tail(&kcontrol->list, &card->controls);
 341         card->controls_count += kcontrol->count;
 342         kcontrol->id.numid = card->last_numid + 1;
 343         card->last_numid += kcontrol->count;
 344         up_write(&card->controls_rwsem);
 345         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 346                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 347         return 0;
 348
 349  error:
 350         snd_ctl_free_one(kcontrol);
 351         return err;
 352 }
 353
 354 EXPORT_SYMBOL(snd_ctl_add);
 355
 356 /**
 357  * snd_ctl_remove - remove the control from the card and release it
 358  * @card: the card instance
 359  * @kcontrol: the control instance to remove
 360  *
 361  * Removes the control from the card and then releases the instance.
 362  * You don't need to call snd_ctl_free_one(). You must be in
 363  * the write lock - down_write(&card->controls_rwsem).
 364  *
 365  * Returns 0 if successful, or a negative error code on failure.
 366  */
 367 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 368 {
 369         struct snd_ctl_elem_id id;
 370         unsigned int idx;
 371
 372         snd_assert(card != NULL && kcontrol != NULL, return -EINVAL);
 373         list_del(&kcontrol->list);
 374         card->controls_count -= kcontrol->count;
 375         id = kcontrol->id;
 376         for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 377                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
 378         snd_ctl_free_one(kcontrol);
 379         return 0;
 380 }
 381
 382 EXPORT_SYMBOL(snd_ctl_remove);
 383
 384 /**
 385  * snd_ctl_remove_id - remove the control of the given id and release it
 386  * @card: the card instance
 387  * @id: the control id to remove
 388  *
 389  * Finds the control instance with the given id, removes it from the
 390  * card list and releases it.
 391  *
 392  * Returns 0 if successful, or a negative error code on failure.
 393  */
 394 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 395 {
 396         struct snd_kcontrol *kctl;
 397         int ret;
 398
 399         down_write(&card->controls_rwsem);
 400         kctl = snd_ctl_find_id(card, id);
 401         if (kctl == NULL) {
 402                 up_write(&card->controls_rwsem);
 403                 return -ENOENT;
 404         }
 405         ret = snd_ctl_remove(card, kctl);
 406         up_write(&card->controls_rwsem);
 407         return ret;
 408 }
 409
 410 EXPORT_SYMBOL(snd_ctl_remove_id);
 411
 412 /**
 413  * snd_ctl_remove_unlocked_id - remove the unlocked control of the given id and release it
 414  * @file: active control handle
 415  * @id: the control id to remove
 416  *
 417  * Finds the control instance with the given id, removes it from the
 418  * card list and releases it.
 419  *
 420  * Returns 0 if successful, or a negative error code on failure.
 421  */
 422 static int snd_ctl_remove_unlocked_id(struct snd_ctl_file * file,
 423                                       struct snd_ctl_elem_id *id)
 424 {
 425         struct snd_card *card = file->card;
 426         struct snd_kcontrol *kctl;
 427         int idx, ret;
 428
 429         down_write(&card->controls_rwsem);
 430         kctl = snd_ctl_find_id(card, id);
 431         if (kctl == NULL) {
 432                 up_write(&card->controls_rwsem);
 433                 return -ENOENT;
 434         }
 435         for (idx = 0; idx < kctl->count; idx++)
 436                 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
 437                         up_write(&card->controls_rwsem);
 438                         return -EBUSY;
 439                 }
 440         ret = snd_ctl_remove(card, kctl);
 441         up_write(&card->controls_rwsem);
 442         return ret;
 443 }
 444
 445 /**
 446  * snd_ctl_rename_id - replace the id of a control on the card
 447  * @card: the card instance
 448  * @src_id: the old id
 449  * @dst_id: the new id
 450  *
 451  * Finds the control with the old id from the card, and replaces the
 452  * id with the new one.
 453  *
 454  * Returns zero if successful, or a negative error code on failure.
 455  */
 456 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 457                       struct snd_ctl_elem_id *dst_id)
 458 {
 459         struct snd_kcontrol *kctl;
 460
 461         down_write(&card->controls_rwsem);
 462         kctl = snd_ctl_find_id(card, src_id);
 463         if (kctl == NULL) {
 464                 up_write(&card->controls_rwsem);
 465                 return -ENOENT;
 466         }
 467         kctl->id = *dst_id;
 468         kctl->id.numid = card->last_numid + 1;
 469         card->last_numid += kctl->count;
 470         up_write(&card->controls_rwsem);
 471         return 0;
 472 }
 473
 474 EXPORT_SYMBOL(snd_ctl_rename_id);
 475
 476 /**
 477  * snd_ctl_find_numid - find the control instance with the given number-id
 478  * @card: the card instance
 479  * @numid: the number-id to search
 480  *
 481  * Finds the control instance with the given number-id from the card.
 482  *
 483  * Returns the pointer of the instance if found, or NULL if not.
 484  *
 485  * The caller must down card->controls_rwsem before calling this function
 486  * (if the race condition can happen).
 487  */
 488 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 489 {
 490         struct snd_kcontrol *kctl;
 491
 492         snd_assert(card != NULL && numid != 0, return NULL);
 493         list_for_each_entry(kctl, &card->controls, list) {
 494                 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 495                         return kctl;
 496         }
 497         return NULL;
 498 }
 499
 500 EXPORT_SYMBOL(snd_ctl_find_numid);
 501
 502 /**
 503  * snd_ctl_find_id - find the control instance with the given id
 504  * @card: the card instance
 505  * @id: the id to search
 506  *
 507  * Finds the control instance with the given id from the card.
 508  *
 509  * Returns the pointer of the instance if found, or NULL if not.
 510  *
 511  * The caller must down card->controls_rwsem before calling this function
 512  * (if the race condition can happen).
 513  */
 514 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 515                                      struct snd_ctl_elem_id *id)
 516 {
 517         struct snd_kcontrol *kctl;
 518
 519         snd_assert(card != NULL && id != NULL, return NULL);
 520         if (id->numid != 0)
 521                 return snd_ctl_find_numid(card, id->numid);
 522         list_for_each_entry(kctl, &card->controls, list) {
 523                 if (kctl->id.iface != id->iface)
 524                         continue;
 525                 if (kctl->id.device != id->device)
 526                         continue;
 527                 if (kctl->id.subdevice != id->subdevice)
 528                         continue;
 529                 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
 530                         continue;
 531                 if (kctl->id.index > id->index)
 532                         continue;
 533                 if (kctl->id.index + kctl->count <= id->index)
 534                         continue;
 535                 return kctl;
 536         }
 537         return NULL;
 538 }
 539
 540 EXPORT_SYMBOL(snd_ctl_find_id);
 541
 542 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 543                              unsigned int cmd, void __user *arg)
 544 {
 545         struct snd_ctl_card_info *info;
 546
 547         info = kzalloc(sizeof(*info), GFP_KERNEL);
 548         if (! info)
 549                 return -ENOMEM;
 550         down_read(&snd_ioctl_rwsem);
 551         info->card = card->number;
 552         strlcpy(info->id, card->id, sizeof(info->id));
 553         strlcpy(info->driver, card->driver, sizeof(info->driver));
 554         strlcpy(info->name, card->shortname, sizeof(info->name));
 555         strlcpy(info->longname, card->longname, sizeof(info->longname));
 556         strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
 557         strlcpy(info->components, card->components, sizeof(info->components));
 558         up_read(&snd_ioctl_rwsem);
 559         if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 560                 kfree(info);
 561                 return -EFAULT;
 562         }
 563         kfree(info);
 564         return 0;
 565 }
 566
 567 static int snd_ctl_elem_list(struct snd_card *card,
 568                              struct snd_ctl_elem_list __user *_list)
 569 {
 570         struct list_head *plist;
 571         struct snd_ctl_elem_list list;
 572         struct snd_kcontrol *kctl;
 573         struct snd_ctl_elem_id *dst, *id;
 574         unsigned int offset, space, first, jidx;
 575
 576         if (copy_from_user(&list, _list, sizeof(list)))
 577                 return -EFAULT;
 578         offset = list.offset;
 579         space = list.space;
 580         first = 0;
 581         /* try limit maximum space */
 582         if (space > 16384)
 583                 return -ENOMEM;
 584         if (space > 0) {
 585                 /* allocate temporary buffer for atomic operation */
 586                 dst = vmalloc(space * sizeof(struct snd_ctl_elem_id));
 587                 if (dst == NULL)
 588                         return -ENOMEM;
 589                 down_read(&card->controls_rwsem);
 590                 list.count = card->controls_count;
 591                 plist = card->controls.next;
 592                 while (plist != &card->controls) {
 593                         if (offset == 0)
 594                                 break;
 595                         kctl = snd_kcontrol(plist);
 596                         if (offset < kctl->count)
 597                                 break;
 598                         offset -= kctl->count;
 599                         plist = plist->next;
 600                 }
 601                 list.used = 0;
 602                 id = dst;
 603                 while (space > 0 && plist != &card->controls) {
 604                         kctl = snd_kcontrol(plist);
 605                         for (jidx = offset; space > 0 && jidx < kctl->count; jidx++) {
 606                                 snd_ctl_build_ioff(id, kctl, jidx);
 607                                 id++;
 608                                 space--;
 609                                 list.used++;
 610                         }
 611                         plist = plist->next;
 612                         offset = 0;
 613                 }
 614                 up_read(&card->controls_rwsem);
 615                 if (list.used > 0 &&
 616                     copy_to_user(list.pids, dst,
 617                                  list.used * sizeof(struct snd_ctl_elem_id))) {
 618                         vfree(dst);
 619                         return -EFAULT;
 620                 }
 621                 vfree(dst);
 622         } else {
 623                 down_read(&card->controls_rwsem);
 624                 list.count = card->controls_count;
 625                 up_read(&card->controls_rwsem);
 626         }
 627         if (copy_to_user(_list, &list, sizeof(list)))
 628                 return -EFAULT;
 629         return 0;
 630 }
 631
 632 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 633                              struct snd_ctl_elem_info *info)
 634 {
 635         struct snd_card *card = ctl->card;
 636         struct snd_kcontrol *kctl;
 637         struct snd_kcontrol_volatile *vd;
 638         unsigned int index_offset;
 639         int result;
 640
 641         down_read(&card->controls_rwsem);
 642         kctl = snd_ctl_find_id(card, &info->id);
 643         if (kctl == NULL) {
 644                 up_read(&card->controls_rwsem);
 645                 return -ENOENT;
 646         }
 647 #ifdef CONFIG_SND_DEBUG
 648         info->access = 0;
 649 #endif
 650         result = kctl->info(kctl, info);
 651         if (result >= 0) {
 652                 snd_assert(info->access == 0, );
 653                 index_offset = snd_ctl_get_ioff(kctl, &info->id);
 654                 vd = &kctl->vd[index_offset];
 655                 snd_ctl_build_ioff(&info->id, kctl, index_offset);
 656                 info->access = vd->access;
 657                 if (vd->owner) {
 658                         info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
 659                         if (vd->owner == ctl)
 660                                 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
 661                         info->owner = vd->owner_pid;
 662                 } else {
 663                         info->owner = -1;
 664                 }
 665         }
 666         up_read(&card->controls_rwsem);
 667         return result;
 668 }
 669
 670 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
 671                                   struct snd_ctl_elem_info __user *_info)
 672 {
 673         struct snd_ctl_elem_info info;
 674         int result;
 675
 676         if (copy_from_user(&info, _info, sizeof(info)))
 677                 return -EFAULT;
 678         snd_power_lock(ctl->card);
 679         result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
 680         if (result >= 0)
 681                 result = snd_ctl_elem_info(ctl, &info);
 682         snd_power_unlock(ctl->card);
 683         if (result >= 0)
 684                 if (copy_to_user(_info, &info, sizeof(info)))
 685                         return -EFAULT;
 686         return result;
 687 }
 688
 689 int snd_ctl_elem_read(struct snd_card *card, struct snd_ctl_elem_value *control)
 690 {
 691         struct snd_kcontrol *kctl;
 692         struct snd_kcontrol_volatile *vd;
 693         unsigned int index_offset;
 694         int result, indirect;
 695
 696         down_read(&card->controls_rwsem);
 697         kctl = snd_ctl_find_id(card, &control->id);
 698         if (kctl == NULL) {
 699                 result = -ENOENT;
 700         } else {
 701                 index_offset = snd_ctl_get_ioff(kctl, &control->id);
 702                 vd = &kctl->vd[index_offset];
 703                 indirect = vd->access & SNDRV_CTL_ELEM_ACCESS_INDIRECT ? 1 : 0;
 704                 if (control->indirect != indirect) {
 705                         result = -EACCES;
 706                 } else {
 707                         if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) && kctl->get != NULL) {
 708                                 snd_ctl_build_ioff(&control->id, kctl, index_offset);
 709                                 result = kctl->get(kctl, control);
 710                         } else {
 711                                 result = -EPERM;
 712                         }
 713                 }
 714         }
 715         up_read(&card->controls_rwsem);
 716         return result;
 717 }
 718
 719 static int snd_ctl_elem_read_user(struct snd_card *card,
 720                                   struct snd_ctl_elem_value __user *_control)
 721 {
 722         struct snd_ctl_elem_value *control;
 723         int result;
 724
 725         control = kmalloc(sizeof(*control), GFP_KERNEL);
 726         if (control == NULL)
 727                 return -ENOMEM;
 728         if (copy_from_user(control, _control, sizeof(*control))) {
 729                 kfree(control);
 730                 return -EFAULT;
 731         }
 732         snd_power_lock(card);
 733         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 734         if (result >= 0)
 735                 result = snd_ctl_elem_read(card, control);
 736         snd_power_unlock(card);
 737         if (result >= 0)
 738                 if (copy_to_user(_control, control, sizeof(*control)))
 739                         result = -EFAULT;
 740         kfree(control);
 741         return result;
 742 }
 743
 744 int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
 745                        struct snd_ctl_elem_value *control)
 746 {
 747         struct snd_kcontrol *kctl;
 748         struct snd_kcontrol_volatile *vd;
 749         unsigned int index_offset;
 750         int result, indirect;
 751
 752         down_read(&card->controls_rwsem);
 753         kctl = snd_ctl_find_id(card, &control->id);
 754         if (kctl == NULL) {
 755                 result = -ENOENT;
 756         } else {
 757                 index_offset = snd_ctl_get_ioff(kctl, &control->id);
 758                 vd = &kctl->vd[index_offset];
 759                 indirect = vd->access & SNDRV_CTL_ELEM_ACCESS_INDIRECT ? 1 : 0;
 760                 if (control->indirect != indirect) {
 761                         result = -EACCES;
 762                 } else {
 763                         if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
 764                             kctl->put == NULL ||
 765                             (file && vd->owner != NULL && vd->owner != file)) {
 766                                 result = -EPERM;
 767                         } else {
 768                                 snd_ctl_build_ioff(&control->id, kctl, index_offset);
 769                                 result = kctl->put(kctl, control);
 770                         }
 771                         if (result > 0) {
 772                                 up_read(&card->controls_rwsem);
 773                                 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &control->id);
 774                                 return 0;
 775                         }
 776                 }
 777         }
 778         up_read(&card->controls_rwsem);
 779         return result;
 780 }
 781
 782 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
 783                                    struct snd_ctl_elem_value __user *_control)
 784 {
 785         struct snd_ctl_elem_value *control;
 786         struct snd_card *card;
 787         int result;
 788
 789         control = kmalloc(sizeof(*control), GFP_KERNEL);
 790         if (control == NULL)
 791                 return -ENOMEM;
 792         if (copy_from_user(control, _control, sizeof(*control))) {
 793                 kfree(control);
 794                 return -EFAULT;
 795         }
 796         card = file->card;
 797         snd_power_lock(card);
 798         result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 799         if (result >= 0)
 800                 result = snd_ctl_elem_write(card, file, control);
 801         snd_power_unlock(card);
 802         if (result >= 0)
 803                 if (copy_to_user(_control, control, sizeof(*control)))
 804                         result = -EFAULT;
 805         kfree(control);
 806         return result;
 807 }
 808
 809 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
 810                              struct snd_ctl_elem_id __user *_id)
 811 {
 812         struct snd_card *card = file->card;
 813         struct snd_ctl_elem_id id;
 814         struct snd_kcontrol *kctl;
 815         struct snd_kcontrol_volatile *vd;
 816         int result;
 817
 818         if (copy_from_user(&id, _id, sizeof(id)))
 819                 return -EFAULT;
 820         down_write(&card->controls_rwsem);
 821         kctl = snd_ctl_find_id(card, &id);
 822         if (kctl == NULL) {
 823                 result = -ENOENT;
 824         } else {
 825                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
 826                 if (vd->owner != NULL)
 827                         result = -EBUSY;
 828                 else {
 829                         vd->owner = file;
 830                         vd->owner_pid = current->pid;
 831                         result = 0;
 832                 }
 833         }
 834         up_write(&card->controls_rwsem);
 835         return result;
 836 }
 837
 838 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
 839                                struct snd_ctl_elem_id __user *_id)
 840 {
 841         struct snd_card *card = file->card;
 842         struct snd_ctl_elem_id id;
 843         struct snd_kcontrol *kctl;
 844         struct snd_kcontrol_volatile *vd;
 845         int result;
 846
 847         if (copy_from_user(&id, _id, sizeof(id)))
 848                 return -EFAULT;
 849         down_write(&card->controls_rwsem);
 850         kctl = snd_ctl_find_id(card, &id);
 851         if (kctl == NULL) {
 852                 result = -ENOENT;
 853         } else {
 854                 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
 855                 if (vd->owner == NULL)
 856                         result = -EINVAL;
 857                 else if (vd->owner != file)
 858                         result = -EPERM;
 859                 else {
 860                         vd->owner = NULL;
 861                         vd->owner_pid = 0;
 862                         result = 0;
 863                 }
 864         }
 865         up_write(&card->controls_rwsem);
 866         return result;
 867 }
 868
 869 struct user_element {
 870         struct snd_ctl_elem_info info;
 871         void *elem_data;                /* element data */
 872         unsigned long elem_data_size;   /* size of element data in bytes */
 873         void *tlv_data;                 /* TLV data */
 874         unsigned long tlv_data_size;    /* TLV data size */
 875         void *priv_data;                /* private data (like strings for enumerated type) */
 876         unsigned long priv_data_size;   /* size of private data in bytes */
 877 };
 878
 879 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
 880                                   struct snd_ctl_elem_info *uinfo)
 881 {
 882         struct user_element *ue = kcontrol->private_data;
 883
 884         *uinfo = ue->info;
 885         return 0;
 886 }
 887
 888 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
 889                                  struct snd_ctl_elem_value *ucontrol)
 890 {
 891         struct user_element *ue = kcontrol->private_data;
 892
 893         memcpy(&ucontrol->value, ue->elem_data, ue->elem_data_size);
 894         return 0;
 895 }
 896
 897 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
 898                                  struct snd_ctl_elem_value *ucontrol)
 899 {
 900         int change;
 901         struct user_element *ue = kcontrol->private_data;
 902
 903         change = memcmp(&ucontrol->value, ue->elem_data, ue->elem_data_size) != 0;
 904         if (change)
 905                 memcpy(ue->elem_data, &ucontrol->value, ue->elem_data_size);
 906         return change;
 907 }
 908
 909 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol,
 910                                  int op_flag,
 911                                  unsigned int size,
 912                                  unsigned int __user *tlv)
 913 {
 914         struct user_element *ue = kcontrol->private_data;
 915         int change = 0;
 916         void *new_data;
 917
 918         if (op_flag > 0) {
 919                 if (size > 1024 * 128)  /* sane value */
 920                         return -EINVAL;
 921                 new_data = kmalloc(size, GFP_KERNEL);
 922                 if (new_data == NULL)
 923                         return -ENOMEM;
 924                 if (copy_from_user(new_data, tlv, size)) {
 925                         kfree(new_data);
 926                         return -EFAULT;
 927                 }
 928                 change = ue->tlv_data_size != size;
 929                 if (!change)
 930                         change = memcmp(ue->tlv_data, new_data, size);
 931                 kfree(ue->tlv_data);
 932                 ue->tlv_data = new_data;
 933                 ue->tlv_data_size = size;
 934         } else {
 935                 if (! ue->tlv_data_size || ! ue->tlv_data)
 936                         return -ENXIO;
 937                 if (size < ue->tlv_data_size)
 938                         return -ENOSPC;
 939                 if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size))
 940                         return -EFAULT;
 941         }
 942         return change;
 943 }
 944
 945 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
 946 {
 947         struct user_element *ue = kcontrol->private_data;
 948         if (ue->tlv_data)
 949                 kfree(ue->tlv_data);
 950         kfree(ue);
 951 }
 952
 953 static int snd_ctl_elem_add(struct snd_ctl_file *file,
 954                             struct snd_ctl_elem_info *info, int replace)
 955 {
 956         struct snd_card *card = file->card;
 957         struct snd_kcontrol kctl, *_kctl;
 958         unsigned int access;
 959         long private_size;
 960         struct user_element *ue;
 961         int idx, err;
 962
 963         if (card->user_ctl_count >= MAX_USER_CONTROLS)
 964                 return -ENOMEM;
 965         if (info->count > 1024)
 966                 return -EINVAL;
 967         access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
 968                 (info->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
 969                                  SNDRV_CTL_ELEM_ACCESS_INACTIVE|
 970                                  SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE));
 971         info->id.numid = 0;
 972         memset(&kctl, 0, sizeof(kctl));
 973         down_write(&card->controls_rwsem);
 974         _kctl = snd_ctl_find_id(card, &info->id);
 975         err = 0;
 976         if (_kctl) {
 977                 if (replace)
 978                         err = snd_ctl_remove(card, _kctl);
 979                 else
 980                         err = -EBUSY;
 981         } else {
 982                 if (replace)
 983                         err = -ENOENT;
 984         }
 985         up_write(&card->controls_rwsem);
 986         if (err < 0)
 987                 return err;
 988         memcpy(&kctl.id, &info->id, sizeof(info->id));
 989         kctl.count = info->owner ? info->owner : 1;
 990         access |= SNDRV_CTL_ELEM_ACCESS_USER;
 991         kctl.info = snd_ctl_elem_user_info;
 992         if (access & SNDRV_CTL_ELEM_ACCESS_READ)
 993                 kctl.get = snd_ctl_elem_user_get;
 994         if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
 995                 kctl.put = snd_ctl_elem_user_put;
 996         if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE) {
 997                 kctl.tlv.c = snd_ctl_elem_user_tlv;
 998                 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
 999         }
1000         switch (info->type) {
1001         case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
1002         case SNDRV_CTL_ELEM_TYPE_INTEGER:
1003                 private_size = sizeof(long);
1004                 if (info->count > 128)
1005                         return -EINVAL;
1006                 break;
1007         case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1008                 private_size = sizeof(long long);
1009                 if (info->count > 64)
1010                         return -EINVAL;
1011                 break;
1012         case SNDRV_CTL_ELEM_TYPE_BYTES:
1013                 private_size = sizeof(unsigned char);
1014                 if (info->count > 512)
1015                         return -EINVAL;
1016                 break;
1017         case SNDRV_CTL_ELEM_TYPE_IEC958:
1018                 private_size = sizeof(struct snd_aes_iec958);
1019                 if (info->count != 1)
1020                         return -EINVAL;
1021                 break;
1022         default:
1023                 return -EINVAL;
1024         }
1025         private_size *= info->count;
1026         ue = kzalloc(sizeof(struct user_element) + private_size, GFP_KERNEL);
1027         if (ue == NULL)
1028                 return -ENOMEM;
1029         ue->info = *info;
1030         ue->info.access = 0;
1031         ue->elem_data = (char *)ue + sizeof(*ue);
1032         ue->elem_data_size = private_size;
1033         kctl.private_free = snd_ctl_elem_user_free;
1034         _kctl = snd_ctl_new(&kctl, access);
1035         if (_kctl == NULL) {
1036                 kfree(ue);
1037                 return -ENOMEM;
1038         }
1039         _kctl->private_data = ue;
1040         for (idx = 0; idx < _kctl->count; idx++)
1041                 _kctl->vd[idx].owner = file;
1042         err = snd_ctl_add(card, _kctl);
1043         if (err < 0)
1044                 return err;
1045
1046         down_write(&card->controls_rwsem);
1047         card->user_ctl_count++;
1048         up_write(&card->controls_rwsem);
1049
1050         return 0;
1051 }
1052
1053 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1054                                  struct snd_ctl_elem_info __user *_info, int replace)
1055 {
1056         struct snd_ctl_elem_info info;
1057         if (copy_from_user(&info, _info, sizeof(info)))
1058                 return -EFAULT;
1059         return snd_ctl_elem_add(file, &info, replace);
1060 }
1061
1062 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1063                                struct snd_ctl_elem_id __user *_id)
1064 {
1065         struct snd_ctl_elem_id id;
1066         int err;
1067
1068         if (copy_from_user(&id, _id, sizeof(id)))
1069                 return -EFAULT;
1070         err = snd_ctl_remove_unlocked_id(file, &id);
1071         if (! err) {
1072                 struct snd_card *card = file->card;
1073                 down_write(&card->controls_rwsem);
1074                 card->user_ctl_count--;
1075                 up_write(&card->controls_rwsem);
1076         }
1077         return err;
1078 }
1079
1080 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1081 {
1082         int subscribe;
1083         if (get_user(subscribe, ptr))
1084                 return -EFAULT;
1085         if (subscribe < 0) {
1086                 subscribe = file->subscribed;
1087                 if (put_user(subscribe, ptr))
1088                         return -EFAULT;
1089                 return 0;
1090         }
1091         if (subscribe) {
1092                 file->subscribed = 1;
1093                 return 0;
1094         } else if (file->subscribed) {
1095                 snd_ctl_empty_read_queue(file);
1096                 file->subscribed = 0;
1097         }
1098         return 0;
1099 }
1100
1101 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1102                              struct snd_ctl_tlv __user *_tlv,
1103                              int op_flag)
1104 {
1105         struct snd_card *card = file->card;
1106         struct snd_ctl_tlv tlv;
1107         struct snd_kcontrol *kctl;
1108         struct snd_kcontrol_volatile *vd;
1109         unsigned int len;
1110         int err = 0;
1111
1112         if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
1113                 return -EFAULT;
1114         if (tlv.length < sizeof(unsigned int) * 3)
1115                 return -EINVAL;
1116         down_read(&card->controls_rwsem);
1117         kctl = snd_ctl_find_numid(card, tlv.numid);
1118         if (kctl == NULL) {
1119                 err = -ENOENT;
1120                 goto __kctl_end;
1121         }
1122         if (kctl->tlv.p == NULL) {
1123                 err = -ENXIO;
1124                 goto __kctl_end;
1125         }
1126         vd = &kctl->vd[tlv.numid - kctl->id.numid];
1127         if ((op_flag == 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||
1128             (op_flag > 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||
1129             (op_flag < 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0)) {
1130                 err = -ENXIO;
1131                 goto __kctl_end;
1132         }
1133         if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1134                 if (file && vd->owner != NULL && vd->owner != file) {
1135                         err = -EPERM;
1136                         goto __kctl_end;
1137                 }
1138                 err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv);
1139                 if (err > 0) {
1140                         up_read(&card->controls_rwsem);
1141                         snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &kctl->id);
1142                         return 0;
1143                 }
1144         } else {
1145                 if (op_flag) {
1146                         err = -ENXIO;
1147                         goto __kctl_end;
1148                 }
1149                 len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);
1150                 if (tlv.length < len) {
1151                         err = -ENOMEM;
1152                         goto __kctl_end;
1153                 }
1154                 if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))
1155                         err = -EFAULT;
1156         }
1157       __kctl_end:
1158         up_read(&card->controls_rwsem);
1159         return err;
1160 }
1161
1162 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1163 {
1164         struct snd_ctl_file *ctl;
1165         struct snd_card *card;
1166         struct snd_kctl_ioctl *p;
1167         void __user *argp = (void __user *)arg;
1168         int __user *ip = argp;
1169         int err;
1170
1171         ctl = file->private_data;
1172         card = ctl->card;
1173         snd_assert(card != NULL, return -ENXIO);
1174         switch (cmd) {
1175         case SNDRV_CTL_IOCTL_PVERSION:
1176                 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1177         case SNDRV_CTL_IOCTL_CARD_INFO:
1178                 return snd_ctl_card_info(card, ctl, cmd, argp);
1179         case SNDRV_CTL_IOCTL_ELEM_LIST:
1180                 return snd_ctl_elem_list(card, argp);
1181         case SNDRV_CTL_IOCTL_ELEM_INFO:
1182                 return snd_ctl_elem_info_user(ctl, argp);
1183         case SNDRV_CTL_IOCTL_ELEM_READ:
1184                 return snd_ctl_elem_read_user(card, argp);
1185         case SNDRV_CTL_IOCTL_ELEM_WRITE:
1186                 return snd_ctl_elem_write_user(ctl, argp);
1187         case SNDRV_CTL_IOCTL_ELEM_LOCK:
1188                 return snd_ctl_elem_lock(ctl, argp);
1189         case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1190                 return snd_ctl_elem_unlock(ctl, argp);
1191         case SNDRV_CTL_IOCTL_ELEM_ADD:
1192                 return snd_ctl_elem_add_user(ctl, argp, 0);
1193         case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1194                 return snd_ctl_elem_add_user(ctl, argp, 1);
1195         case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1196                 return snd_ctl_elem_remove(ctl, argp);
1197         case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1198                 return snd_ctl_subscribe_events(ctl, ip);
1199         case SNDRV_CTL_IOCTL_TLV_READ:
1200                 return snd_ctl_tlv_ioctl(ctl, argp, 0);
1201         case SNDRV_CTL_IOCTL_TLV_WRITE:
1202                 return snd_ctl_tlv_ioctl(ctl, argp, 1);
1203         case SNDRV_CTL_IOCTL_TLV_COMMAND:
1204                 return snd_ctl_tlv_ioctl(ctl, argp, -1);
1205         case SNDRV_CTL_IOCTL_POWER:
1206                 return -ENOPROTOOPT;
1207         case SNDRV_CTL_IOCTL_POWER_STATE:
1208 #ifdef CONFIG_PM
1209                 return put_user(card->power_state, ip) ? -EFAULT : 0;
1210 #else
1211                 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1212 #endif
1213         }
1214         down_read(&snd_ioctl_rwsem);
1215         list_for_each_entry(p, &snd_control_ioctls, list) {
1216                 err = p->fioctl(card, ctl, cmd, arg);
1217                 if (err != -ENOIOCTLCMD) {
1218                         up_read(&snd_ioctl_rwsem);
1219                         return err;
1220                 }
1221         }
1222         up_read(&snd_ioctl_rwsem);
1223         snd_printdd("unknown ioctl = 0x%x\n", cmd);
1224         return -ENOTTY;
1225 }
1226
1227 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1228                             size_t count, loff_t * offset)
1229 {
1230         struct snd_ctl_file *ctl;
1231         int err = 0;
1232         ssize_t result = 0;
1233
1234         ctl = file->private_data;
1235         snd_assert(ctl != NULL && ctl->card != NULL, return -ENXIO);
1236         if (!ctl->subscribed)
1237                 return -EBADFD;
1238         if (count < sizeof(struct snd_ctl_event))
1239                 return -EINVAL;
1240         spin_lock_irq(&ctl->read_lock);
1241         while (count >= sizeof(struct snd_ctl_event)) {
1242                 struct snd_ctl_event ev;
1243                 struct snd_kctl_event *kev;
1244                 while (list_empty(&ctl->events)) {
1245                         wait_queue_t wait;
1246                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1247                                 err = -EAGAIN;
1248                                 goto __end_lock;
1249                         }
1250                         init_waitqueue_entry(&wait, current);
1251                         add_wait_queue(&ctl->change_sleep, &wait);
1252                         set_current_state(TASK_INTERRUPTIBLE);
1253                         spin_unlock_irq(&ctl->read_lock);
1254                         schedule();
1255                         remove_wait_queue(&ctl->change_sleep, &wait);
1256                         if (signal_pending(current))
1257                                 return -ERESTARTSYS;
1258                         spin_lock_irq(&ctl->read_lock);
1259                 }
1260                 kev = snd_kctl_event(ctl->events.next);
1261                 ev.type = SNDRV_CTL_EVENT_ELEM;
1262                 ev.data.elem.mask = kev->mask;
1263                 ev.data.elem.id = kev->id;
1264                 list_del(&kev->list);
1265                 spin_unlock_irq(&ctl->read_lock);
1266                 kfree(kev);
1267                 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1268                         err = -EFAULT;
1269                         goto __end;
1270                 }
1271                 spin_lock_irq(&ctl->read_lock);
1272                 buffer += sizeof(struct snd_ctl_event);
1273                 count -= sizeof(struct snd_ctl_event);
1274                 result += sizeof(struct snd_ctl_event);
1275         }
1276       __end_lock:
1277         spin_unlock_irq(&ctl->read_lock);
1278       __end:
1279         return result > 0 ? result : err;
1280 }
1281
1282 static unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
1283 {
1284         unsigned int mask;
1285         struct snd_ctl_file *ctl;
1286
1287         ctl = file->private_data;
1288         if (!ctl->subscribed)
1289                 return 0;
1290         poll_wait(file, &ctl->change_sleep, wait);
1291
1292         mask = 0;
1293         if (!list_empty(&ctl->events))
1294                 mask |= POLLIN | POLLRDNORM;
1295
1296         return mask;
1297 }
1298
1299 /*
1300  * register the device-specific control-ioctls.
1301  * called from each device manager like pcm.c, hwdep.c, etc.
1302  */
1303 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1304 {
1305         struct snd_kctl_ioctl *pn;
1306
1307         pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1308         if (pn == NULL)
1309                 return -ENOMEM;
1310         pn->fioctl = fcn;
1311         down_write(&snd_ioctl_rwsem);
1312         list_add_tail(&pn->list, lists);
1313         up_write(&snd_ioctl_rwsem);
1314         return 0;
1315 }
1316
1317 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1318 {
1319         return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1320 }
1321
1322 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1323
1324 #ifdef CONFIG_COMPAT
1325 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1326 {
1327         return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1328 }
1329
1330 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1331 #endif
1332
1333 /*
1334  * de-register the device-specific control-ioctls.
1335  */
1336 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1337                                      struct list_head *lists)
1338 {
1339         struct snd_kctl_ioctl *p;
1340
1341         snd_assert(fcn != NULL, return -EINVAL);
1342         down_write(&snd_ioctl_rwsem);
1343         list_for_each_entry(p, lists, list) {
1344                 if (p->fioctl == fcn) {
1345                         list_del(&p->list);
1346                         up_write(&snd_ioctl_rwsem);
1347                         kfree(p);
1348                         return 0;
1349                 }
1350         }
1351         up_write(&snd_ioctl_rwsem);
1352         snd_BUG();
1353         return -EINVAL;
1354 }
1355
1356 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1357 {
1358         return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1359 }
1360
1361 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1362
1363 #ifdef CONFIG_COMPAT
1364 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1365 {
1366         return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1367 }
1368
1369 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1370 #endif
1371
1372 static int snd_ctl_fasync(int fd, struct file * file, int on)
1373 {
1374         struct snd_ctl_file *ctl;
1375         int err;
1376         ctl = file->private_data;
1377         err = fasync_helper(fd, file, on, &ctl->fasync);
1378         if (err < 0)
1379                 return err;
1380         return 0;
1381 }
1382
1383 /*
1384  * ioctl32 compat
1385  */
1386 #ifdef CONFIG_COMPAT
1387 #include "control_compat.c"
1388 #else
1389 #define snd_ctl_ioctl_compat    NULL
1390 #endif
1391
1392 /*
1393  *  INIT PART
1394  */
1395
1396 static const struct file_operations snd_ctl_f_ops =
1397 {
1398         .owner =        THIS_MODULE,
1399         .read =         snd_ctl_read,
1400         .open =         snd_ctl_open,
1401         .release =      snd_ctl_release,
1402         .poll =         snd_ctl_poll,
1403         .unlocked_ioctl =       snd_ctl_ioctl,
1404         .compat_ioctl = snd_ctl_ioctl_compat,
1405         .fasync =       snd_ctl_fasync,
1406 };
1407
1408 /*
1409  * registration of the control device
1410  */
1411 static int snd_ctl_dev_register(struct snd_device *device)
1412 {
1413         struct snd_card *card = device->device_data;
1414         int err, cardnum;
1415         char name[16];
1416
1417         snd_assert(card != NULL, return -ENXIO);
1418         cardnum = card->number;
1419         snd_assert(cardnum >= 0 && cardnum < SNDRV_CARDS, return -ENXIO);
1420         sprintf(name, "controlC%i", cardnum);
1421         if ((err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
1422                                        &snd_ctl_f_ops, card, name)) < 0)
1423                 return err;
1424         return 0;
1425 }
1426
1427 /*
1428  * disconnection of the control device
1429  */
1430 static int snd_ctl_dev_disconnect(struct snd_device *device)
1431 {
1432         struct snd_card *card = device->device_data;
1433         struct snd_ctl_file *ctl;
1434         int err, cardnum;
1435
1436         snd_assert(card != NULL, return -ENXIO);
1437         cardnum = card->number;
1438         snd_assert(cardnum >= 0 && cardnum < SNDRV_CARDS, return -ENXIO);
1439
1440         down_read(&card->controls_rwsem);
1441         list_for_each_entry(ctl, &card->ctl_files, list) {
1442                 wake_up(&ctl->change_sleep);
1443                 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1444         }
1445         up_read(&card->controls_rwsem);
1446
1447         if ((err = snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL,
1448                                          card, -1)) < 0)
1449                 return err;
1450         return 0;
1451 }
1452
1453 /*
1454  * free all controls
1455  */
1456 static int snd_ctl_dev_free(struct snd_device *device)
1457 {
1458         struct snd_card *card = device->device_data;
1459         struct snd_kcontrol *control;
1460
1461         down_write(&card->controls_rwsem);
1462         while (!list_empty(&card->controls)) {
1463                 control = snd_kcontrol(card->controls.next);
1464                 snd_ctl_remove(card, control);
1465         }
1466         up_write(&card->controls_rwsem);
1467         return 0;
1468 }
1469
1470 /*
1471  * create control core:
1472  * called from init.c
1473  */
1474 int snd_ctl_create(struct snd_card *card)
1475 {
1476         static struct snd_device_ops ops = {
1477                 .dev_free = snd_ctl_dev_free,
1478                 .dev_register = snd_ctl_dev_register,
1479                 .dev_disconnect = snd_ctl_dev_disconnect,
1480         };
1481
1482         snd_assert(card != NULL, return -ENXIO);
1483         return snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1484 }
1485
1486 /*
1487  * Frequently used control callbacks
1488  */
1489 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
1490                               struct snd_ctl_elem_info *uinfo)
1491 {
1492         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1493         uinfo->count = 1;
1494         uinfo->value.integer.min = 0;
1495         uinfo->value.integer.max = 1;
1496         return 0;
1497 }
1498
1499 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
1500
1501 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
1502                                 struct snd_ctl_elem_info *uinfo)
1503 {
1504         uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1505         uinfo->count = 2;
1506         uinfo->value.integer.min = 0;
1507         uinfo->value.integer.max = 1;
1508         return 0;
1509 }
1510
1511 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);