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linux/sound/core/control.c
Takashi Iwai d351cf4603 Merge branch 'topic/misc' into for-linus
2011-03-18 07:39:08 +01:00

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/*
* Routines for driver control interface
* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/threads.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/time.h>
#include <sound/core.h>
#include <sound/minors.h>
#include <sound/info.h>
#include <sound/control.h>
/* max number of user-defined controls */
#define MAX_USER_CONTROLS 32
#define MAX_CONTROL_COUNT 1028
struct snd_kctl_ioctl {
struct list_head list; /* list of all ioctls */
snd_kctl_ioctl_func_t fioctl;
};
static DECLARE_RWSEM(snd_ioctl_rwsem);
static LIST_HEAD(snd_control_ioctls);
#ifdef CONFIG_COMPAT
static LIST_HEAD(snd_control_compat_ioctls);
#endif
static int snd_ctl_open(struct inode *inode, struct file *file)
{
unsigned long flags;
struct snd_card *card;
struct snd_ctl_file *ctl;
int err;
err = nonseekable_open(inode, file);
if (err < 0)
return err;
card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
if (!card) {
err = -ENODEV;
goto __error1;
}
err = snd_card_file_add(card, file);
if (err < 0) {
err = -ENODEV;
goto __error1;
}
if (!try_module_get(card->module)) {
err = -EFAULT;
goto __error2;
}
ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
if (ctl == NULL) {
err = -ENOMEM;
goto __error;
}
INIT_LIST_HEAD(&ctl->events);
init_waitqueue_head(&ctl->change_sleep);
spin_lock_init(&ctl->read_lock);
ctl->card = card;
ctl->prefer_pcm_subdevice = -1;
ctl->prefer_rawmidi_subdevice = -1;
ctl->pid = get_pid(task_pid(current));
file->private_data = ctl;
write_lock_irqsave(&card->ctl_files_rwlock, flags);
list_add_tail(&ctl->list, &card->ctl_files);
write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
return 0;
__error:
module_put(card->module);
__error2:
snd_card_file_remove(card, file);
__error1:
return err;
}
static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
{
unsigned long flags;
struct snd_kctl_event *cread;
spin_lock_irqsave(&ctl->read_lock, flags);
while (!list_empty(&ctl->events)) {
cread = snd_kctl_event(ctl->events.next);
list_del(&cread->list);
kfree(cread);
}
spin_unlock_irqrestore(&ctl->read_lock, flags);
}
static int snd_ctl_release(struct inode *inode, struct file *file)
{
unsigned long flags;
struct snd_card *card;
struct snd_ctl_file *ctl;
struct snd_kcontrol *control;
unsigned int idx;
ctl = file->private_data;
file->private_data = NULL;
card = ctl->card;
write_lock_irqsave(&card->ctl_files_rwlock, flags);
list_del(&ctl->list);
write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
down_write(&card->controls_rwsem);
list_for_each_entry(control, &card->controls, list)
for (idx = 0; idx < control->count; idx++)
if (control->vd[idx].owner == ctl)
control->vd[idx].owner = NULL;
up_write(&card->controls_rwsem);
snd_ctl_empty_read_queue(ctl);
put_pid(ctl->pid);
kfree(ctl);
module_put(card->module);
snd_card_file_remove(card, file);
return 0;
}
void snd_ctl_notify(struct snd_card *card, unsigned int mask,
struct snd_ctl_elem_id *id)
{
unsigned long flags;
struct snd_ctl_file *ctl;
struct snd_kctl_event *ev;
if (snd_BUG_ON(!card || !id))
return;
read_lock(&card->ctl_files_rwlock);
#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
card->mixer_oss_change_count++;
#endif
list_for_each_entry(ctl, &card->ctl_files, list) {
if (!ctl->subscribed)
continue;
spin_lock_irqsave(&ctl->read_lock, flags);
list_for_each_entry(ev, &ctl->events, list) {
if (ev->id.numid == id->numid) {
ev->mask |= mask;
goto _found;
}
}
ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
if (ev) {
ev->id = *id;
ev->mask = mask;
list_add_tail(&ev->list, &ctl->events);
} else {
snd_printk(KERN_ERR "No memory available to allocate event\n");
}
_found:
wake_up(&ctl->change_sleep);
spin_unlock_irqrestore(&ctl->read_lock, flags);
kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
}
read_unlock(&card->ctl_files_rwlock);
}
EXPORT_SYMBOL(snd_ctl_notify);
/**
* snd_ctl_new - create a control instance from the template
* @control: the control template
* @access: the default control access
*
* Allocates a new struct snd_kcontrol instance and copies the given template
* to the new instance. It does not copy volatile data (access).
*
* Returns the pointer of the new instance, or NULL on failure.
*/
static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control,
unsigned int access)
{
struct snd_kcontrol *kctl;
unsigned int idx;
if (snd_BUG_ON(!control || !control->count))
return NULL;
if (control->count > MAX_CONTROL_COUNT)
return NULL;
kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL);
if (kctl == NULL) {
snd_printk(KERN_ERR "Cannot allocate control instance\n");
return NULL;
}
*kctl = *control;
for (idx = 0; idx < kctl->count; idx++)
kctl->vd[idx].access = access;
return kctl;
}
/**
* snd_ctl_new1 - create a control instance from the template
* @ncontrol: the initialization record
* @private_data: the private data to set
*
* Allocates a new struct snd_kcontrol instance and initialize from the given
* template. When the access field of ncontrol is 0, it's assumed as
* READWRITE access. When the count field is 0, it's assumes as one.
*
* Returns the pointer of the newly generated instance, or NULL on failure.
*/
struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
void *private_data)
{
struct snd_kcontrol kctl;
unsigned int access;
if (snd_BUG_ON(!ncontrol || !ncontrol->info))
return NULL;
memset(&kctl, 0, sizeof(kctl));
kctl.id.iface = ncontrol->iface;
kctl.id.device = ncontrol->device;
kctl.id.subdevice = ncontrol->subdevice;
if (ncontrol->name) {
strlcpy(kctl.id.name, ncontrol->name, sizeof(kctl.id.name));
if (strcmp(ncontrol->name, kctl.id.name) != 0)
snd_printk(KERN_WARNING
"Control name '%s' truncated to '%s'\n",
ncontrol->name, kctl.id.name);
}
kctl.id.index = ncontrol->index;
kctl.count = ncontrol->count ? ncontrol->count : 1;
access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
(ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
SNDRV_CTL_ELEM_ACCESS_INACTIVE|
SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE|
SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND|
SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK));
kctl.info = ncontrol->info;
kctl.get = ncontrol->get;
kctl.put = ncontrol->put;
kctl.tlv.p = ncontrol->tlv.p;
kctl.private_value = ncontrol->private_value;
kctl.private_data = private_data;
return snd_ctl_new(&kctl, access);
}
EXPORT_SYMBOL(snd_ctl_new1);
/**
* snd_ctl_free_one - release the control instance
* @kcontrol: the control instance
*
* Releases the control instance created via snd_ctl_new()
* or snd_ctl_new1().
* Don't call this after the control was added to the card.
*/
void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
{
if (kcontrol) {
if (kcontrol->private_free)
kcontrol->private_free(kcontrol);
kfree(kcontrol);
}
}
EXPORT_SYMBOL(snd_ctl_free_one);
static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
unsigned int count)
{
struct snd_kcontrol *kctl;
list_for_each_entry(kctl, &card->controls, list) {
if (kctl->id.numid < card->last_numid + 1 + count &&
kctl->id.numid + kctl->count > card->last_numid + 1) {
card->last_numid = kctl->id.numid + kctl->count - 1;
return true;
}
}
return false;
}
static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
{
unsigned int iter = 100000;
while (snd_ctl_remove_numid_conflict(card, count)) {
if (--iter == 0) {
/* this situation is very unlikely */
snd_printk(KERN_ERR "unable to allocate new control numid\n");
return -ENOMEM;
}
}
return 0;
}
/**
* snd_ctl_add - add the control instance to the card
* @card: the card instance
* @kcontrol: the control instance to add
*
* Adds the control instance created via snd_ctl_new() or
* snd_ctl_new1() to the given card. Assigns also an unique
* numid used for fast search.
*
* Returns zero if successful, or a negative error code on failure.
*
* It frees automatically the control which cannot be added.
*/
int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
{
struct snd_ctl_elem_id id;
unsigned int idx;
int err = -EINVAL;
if (! kcontrol)
return err;
if (snd_BUG_ON(!card || !kcontrol->info))
goto error;
id = kcontrol->id;
down_write(&card->controls_rwsem);
if (snd_ctl_find_id(card, &id)) {
up_write(&card->controls_rwsem);
snd_printd(KERN_ERR "control %i:%i:%i:%s:%i is already present\n",
id.iface,
id.device,
id.subdevice,
id.name,
id.index);
err = -EBUSY;
goto error;
}
if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
up_write(&card->controls_rwsem);
err = -ENOMEM;
goto error;
}
list_add_tail(&kcontrol->list, &card->controls);
card->controls_count += kcontrol->count;
kcontrol->id.numid = card->last_numid + 1;
card->last_numid += kcontrol->count;
up_write(&card->controls_rwsem);
for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
return 0;
error:
snd_ctl_free_one(kcontrol);
return err;
}
EXPORT_SYMBOL(snd_ctl_add);
/**
* snd_ctl_remove - remove the control from the card and release it
* @card: the card instance
* @kcontrol: the control instance to remove
*
* Removes the control from the card and then releases the instance.
* You don't need to call snd_ctl_free_one(). You must be in
* the write lock - down_write(&card->controls_rwsem).
*
* Returns 0 if successful, or a negative error code on failure.
*/
int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
{
struct snd_ctl_elem_id id;
unsigned int idx;
if (snd_BUG_ON(!card || !kcontrol))
return -EINVAL;
list_del(&kcontrol->list);
card->controls_count -= kcontrol->count;
id = kcontrol->id;
for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
snd_ctl_free_one(kcontrol);
return 0;
}
EXPORT_SYMBOL(snd_ctl_remove);
/**
* snd_ctl_remove_id - remove the control of the given id and release it
* @card: the card instance
* @id: the control id to remove
*
* Finds the control instance with the given id, removes it from the
* card list and releases it.
*
* Returns 0 if successful, or a negative error code on failure.
*/
int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
{
struct snd_kcontrol *kctl;
int ret;
down_write(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, id);
if (kctl == NULL) {
up_write(&card->controls_rwsem);
return -ENOENT;
}
ret = snd_ctl_remove(card, kctl);
up_write(&card->controls_rwsem);
return ret;
}
EXPORT_SYMBOL(snd_ctl_remove_id);
/**
* snd_ctl_remove_user_ctl - remove and release the unlocked user control
* @file: active control handle
* @id: the control id to remove
*
* Finds the control instance with the given id, removes it from the
* card list and releases it.
*
* Returns 0 if successful, or a negative error code on failure.
*/
static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
struct snd_ctl_elem_id *id)
{
struct snd_card *card = file->card;
struct snd_kcontrol *kctl;
int idx, ret;
down_write(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, id);
if (kctl == NULL) {
ret = -ENOENT;
goto error;
}
if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
ret = -EINVAL;
goto error;
}
for (idx = 0; idx < kctl->count; idx++)
if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
ret = -EBUSY;
goto error;
}
ret = snd_ctl_remove(card, kctl);
if (ret < 0)
goto error;
card->user_ctl_count--;
error:
up_write(&card->controls_rwsem);
return ret;
}
/**
* snd_ctl_activate_id - activate/inactivate the control of the given id
* @card: the card instance
* @id: the control id to activate/inactivate
* @active: non-zero to activate
*
* Finds the control instance with the given id, and activate or
* inactivate the control together with notification, if changed.
*
* Returns 0 if unchanged, 1 if changed, or a negative error code on failure.
*/
int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
int active)
{
struct snd_kcontrol *kctl;
struct snd_kcontrol_volatile *vd;
unsigned int index_offset;
int ret;
down_write(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, id);
if (kctl == NULL) {
ret = -ENOENT;
goto unlock;
}
index_offset = snd_ctl_get_ioff(kctl, &kctl->id);
vd = &kctl->vd[index_offset];
ret = 0;
if (active) {
if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
goto unlock;
vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
} else {
if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
goto unlock;
vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
}
ret = 1;
unlock:
up_write(&card->controls_rwsem);
if (ret > 0)
snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
return ret;
}
EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
/**
* snd_ctl_rename_id - replace the id of a control on the card
* @card: the card instance
* @src_id: the old id
* @dst_id: the new id
*
* Finds the control with the old id from the card, and replaces the
* id with the new one.
*
* Returns zero if successful, or a negative error code on failure.
*/
int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
struct snd_ctl_elem_id *dst_id)
{
struct snd_kcontrol *kctl;
down_write(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, src_id);
if (kctl == NULL) {
up_write(&card->controls_rwsem);
return -ENOENT;
}
kctl->id = *dst_id;
kctl->id.numid = card->last_numid + 1;
card->last_numid += kctl->count;
up_write(&card->controls_rwsem);
return 0;
}
EXPORT_SYMBOL(snd_ctl_rename_id);
/**
* snd_ctl_find_numid - find the control instance with the given number-id
* @card: the card instance
* @numid: the number-id to search
*
* Finds the control instance with the given number-id from the card.
*
* Returns the pointer of the instance if found, or NULL if not.
*
* The caller must down card->controls_rwsem before calling this function
* (if the race condition can happen).
*/
struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
{
struct snd_kcontrol *kctl;
if (snd_BUG_ON(!card || !numid))
return NULL;
list_for_each_entry(kctl, &card->controls, list) {
if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
return kctl;
}
return NULL;
}
EXPORT_SYMBOL(snd_ctl_find_numid);
/**
* snd_ctl_find_id - find the control instance with the given id
* @card: the card instance
* @id: the id to search
*
* Finds the control instance with the given id from the card.
*
* Returns the pointer of the instance if found, or NULL if not.
*
* The caller must down card->controls_rwsem before calling this function
* (if the race condition can happen).
*/
struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
struct snd_ctl_elem_id *id)
{
struct snd_kcontrol *kctl;
if (snd_BUG_ON(!card || !id))
return NULL;
if (id->numid != 0)
return snd_ctl_find_numid(card, id->numid);
list_for_each_entry(kctl, &card->controls, list) {
if (kctl->id.iface != id->iface)
continue;
if (kctl->id.device != id->device)
continue;
if (kctl->id.subdevice != id->subdevice)
continue;
if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
continue;
if (kctl->id.index > id->index)
continue;
if (kctl->id.index + kctl->count <= id->index)
continue;
return kctl;
}
return NULL;
}
EXPORT_SYMBOL(snd_ctl_find_id);
static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
unsigned int cmd, void __user *arg)
{
struct snd_ctl_card_info *info;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (! info)
return -ENOMEM;
down_read(&snd_ioctl_rwsem);
info->card = card->number;
strlcpy(info->id, card->id, sizeof(info->id));
strlcpy(info->driver, card->driver, sizeof(info->driver));
strlcpy(info->name, card->shortname, sizeof(info->name));
strlcpy(info->longname, card->longname, sizeof(info->longname));
strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
strlcpy(info->components, card->components, sizeof(info->components));
up_read(&snd_ioctl_rwsem);
if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
kfree(info);
return -EFAULT;
}
kfree(info);
return 0;
}
static int snd_ctl_elem_list(struct snd_card *card,
struct snd_ctl_elem_list __user *_list)
{
struct list_head *plist;
struct snd_ctl_elem_list list;
struct snd_kcontrol *kctl;
struct snd_ctl_elem_id *dst, *id;
unsigned int offset, space, first, jidx;
if (copy_from_user(&list, _list, sizeof(list)))
return -EFAULT;
offset = list.offset;
space = list.space;
first = 0;
/* try limit maximum space */
if (space > 16384)
return -ENOMEM;
if (space > 0) {
/* allocate temporary buffer for atomic operation */
dst = vmalloc(space * sizeof(struct snd_ctl_elem_id));
if (dst == NULL)
return -ENOMEM;
down_read(&card->controls_rwsem);
list.count = card->controls_count;
plist = card->controls.next;
while (plist != &card->controls) {
if (offset == 0)
break;
kctl = snd_kcontrol(plist);
if (offset < kctl->count)
break;
offset -= kctl->count;
plist = plist->next;
}
list.used = 0;
id = dst;
while (space > 0 && plist != &card->controls) {
kctl = snd_kcontrol(plist);
for (jidx = offset; space > 0 && jidx < kctl->count; jidx++) {
snd_ctl_build_ioff(id, kctl, jidx);
id++;
space--;
list.used++;
}
plist = plist->next;
offset = 0;
}
up_read(&card->controls_rwsem);
if (list.used > 0 &&
copy_to_user(list.pids, dst,
list.used * sizeof(struct snd_ctl_elem_id))) {
vfree(dst);
return -EFAULT;
}
vfree(dst);
} else {
down_read(&card->controls_rwsem);
list.count = card->controls_count;
up_read(&card->controls_rwsem);
}
if (copy_to_user(_list, &list, sizeof(list)))
return -EFAULT;
return 0;
}
static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
struct snd_ctl_elem_info *info)
{
struct snd_card *card = ctl->card;
struct snd_kcontrol *kctl;
struct snd_kcontrol_volatile *vd;
unsigned int index_offset;
int result;
down_read(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, &info->id);
if (kctl == NULL) {
up_read(&card->controls_rwsem);
return -ENOENT;
}
#ifdef CONFIG_SND_DEBUG
info->access = 0;
#endif
result = kctl->info(kctl, info);
if (result >= 0) {
snd_BUG_ON(info->access);
index_offset = snd_ctl_get_ioff(kctl, &info->id);
vd = &kctl->vd[index_offset];
snd_ctl_build_ioff(&info->id, kctl, index_offset);
info->access = vd->access;
if (vd->owner) {
info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
if (vd->owner == ctl)
info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
info->owner = pid_vnr(vd->owner->pid);
} else {
info->owner = -1;
}
}
up_read(&card->controls_rwsem);
return result;
}
static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
struct snd_ctl_elem_info __user *_info)
{
struct snd_ctl_elem_info info;
int result;
if (copy_from_user(&info, _info, sizeof(info)))
return -EFAULT;
snd_power_lock(ctl->card);
result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
if (result >= 0)
result = snd_ctl_elem_info(ctl, &info);
snd_power_unlock(ctl->card);
if (result >= 0)
if (copy_to_user(_info, &info, sizeof(info)))
return -EFAULT;
return result;
}
static int snd_ctl_elem_read(struct snd_card *card,
struct snd_ctl_elem_value *control)
{
struct snd_kcontrol *kctl;
struct snd_kcontrol_volatile *vd;
unsigned int index_offset;
int result;
down_read(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, &control->id);
if (kctl == NULL) {
result = -ENOENT;
} else {
index_offset = snd_ctl_get_ioff(kctl, &control->id);
vd = &kctl->vd[index_offset];
if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) &&
kctl->get != NULL) {
snd_ctl_build_ioff(&control->id, kctl, index_offset);
result = kctl->get(kctl, control);
} else
result = -EPERM;
}
up_read(&card->controls_rwsem);
return result;
}
static int snd_ctl_elem_read_user(struct snd_card *card,
struct snd_ctl_elem_value __user *_control)
{
struct snd_ctl_elem_value *control;
int result;
control = memdup_user(_control, sizeof(*control));
if (IS_ERR(control))
return PTR_ERR(control);
snd_power_lock(card);
result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
if (result >= 0)
result = snd_ctl_elem_read(card, control);
snd_power_unlock(card);
if (result >= 0)
if (copy_to_user(_control, control, sizeof(*control)))
result = -EFAULT;
kfree(control);
return result;
}
static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
struct snd_ctl_elem_value *control)
{
struct snd_kcontrol *kctl;
struct snd_kcontrol_volatile *vd;
unsigned int index_offset;
int result;
down_read(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, &control->id);
if (kctl == NULL) {
result = -ENOENT;
} else {
index_offset = snd_ctl_get_ioff(kctl, &control->id);
vd = &kctl->vd[index_offset];
if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
kctl->put == NULL ||
(file && vd->owner && vd->owner != file)) {
result = -EPERM;
} else {
snd_ctl_build_ioff(&control->id, kctl, index_offset);
result = kctl->put(kctl, control);
}
if (result > 0) {
up_read(&card->controls_rwsem);
snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
&control->id);
return 0;
}
}
up_read(&card->controls_rwsem);
return result;
}
static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
struct snd_ctl_elem_value __user *_control)
{
struct snd_ctl_elem_value *control;
struct snd_card *card;
int result;
control = memdup_user(_control, sizeof(*control));
if (IS_ERR(control))
return PTR_ERR(control);
card = file->card;
snd_power_lock(card);
result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
if (result >= 0)
result = snd_ctl_elem_write(card, file, control);
snd_power_unlock(card);
if (result >= 0)
if (copy_to_user(_control, control, sizeof(*control)))
result = -EFAULT;
kfree(control);
return result;
}
static int snd_ctl_elem_lock(struct snd_ctl_file *file,
struct snd_ctl_elem_id __user *_id)
{
struct snd_card *card = file->card;
struct snd_ctl_elem_id id;
struct snd_kcontrol *kctl;
struct snd_kcontrol_volatile *vd;
int result;
if (copy_from_user(&id, _id, sizeof(id)))
return -EFAULT;
down_write(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, &id);
if (kctl == NULL) {
result = -ENOENT;
} else {
vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
if (vd->owner != NULL)
result = -EBUSY;
else {
vd->owner = file;
result = 0;
}
}
up_write(&card->controls_rwsem);
return result;
}
static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
struct snd_ctl_elem_id __user *_id)
{
struct snd_card *card = file->card;
struct snd_ctl_elem_id id;
struct snd_kcontrol *kctl;
struct snd_kcontrol_volatile *vd;
int result;
if (copy_from_user(&id, _id, sizeof(id)))
return -EFAULT;
down_write(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, &id);
if (kctl == NULL) {
result = -ENOENT;
} else {
vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
if (vd->owner == NULL)
result = -EINVAL;
else if (vd->owner != file)
result = -EPERM;
else {
vd->owner = NULL;
result = 0;
}
}
up_write(&card->controls_rwsem);
return result;
}
struct user_element {
struct snd_ctl_elem_info info;
void *elem_data; /* element data */
unsigned long elem_data_size; /* size of element data in bytes */
void *tlv_data; /* TLV data */
unsigned long tlv_data_size; /* TLV data size */
void *priv_data; /* private data (like strings for enumerated type) */
unsigned long priv_data_size; /* size of private data in bytes */
};
static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_info *uinfo)
{
struct user_element *ue = kcontrol->private_data;
*uinfo = ue->info;
return 0;
}
static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct user_element *ue = kcontrol->private_data;
memcpy(&ucontrol->value, ue->elem_data, ue->elem_data_size);
return 0;
}
static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
int change;
struct user_element *ue = kcontrol->private_data;
change = memcmp(&ucontrol->value, ue->elem_data, ue->elem_data_size) != 0;
if (change)
memcpy(ue->elem_data, &ucontrol->value, ue->elem_data_size);
return change;
}
static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol,
int op_flag,
unsigned int size,
unsigned int __user *tlv)
{
struct user_element *ue = kcontrol->private_data;
int change = 0;
void *new_data;
if (op_flag > 0) {
if (size > 1024 * 128) /* sane value */
return -EINVAL;
new_data = memdup_user(tlv, size);
if (IS_ERR(new_data))
return PTR_ERR(new_data);
change = ue->tlv_data_size != size;
if (!change)
change = memcmp(ue->tlv_data, new_data, size);
kfree(ue->tlv_data);
ue->tlv_data = new_data;
ue->tlv_data_size = size;
} else {
if (! ue->tlv_data_size || ! ue->tlv_data)
return -ENXIO;
if (size < ue->tlv_data_size)
return -ENOSPC;
if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size))
return -EFAULT;
}
return change;
}
static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
{
struct user_element *ue = kcontrol->private_data;
if (ue->tlv_data)
kfree(ue->tlv_data);
kfree(ue);
}
static int snd_ctl_elem_add(struct snd_ctl_file *file,
struct snd_ctl_elem_info *info, int replace)
{
struct snd_card *card = file->card;
struct snd_kcontrol kctl, *_kctl;
unsigned int access;
long private_size;
struct user_element *ue;
int idx, err;
if (card->user_ctl_count >= MAX_USER_CONTROLS)
return -ENOMEM;
if (info->count < 1)
return -EINVAL;
access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
(info->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
SNDRV_CTL_ELEM_ACCESS_INACTIVE|
SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE));
info->id.numid = 0;
memset(&kctl, 0, sizeof(kctl));
down_write(&card->controls_rwsem);
_kctl = snd_ctl_find_id(card, &info->id);
err = 0;
if (_kctl) {
if (replace)
err = snd_ctl_remove(card, _kctl);
else
err = -EBUSY;
} else {
if (replace)
err = -ENOENT;
}
up_write(&card->controls_rwsem);
if (err < 0)
return err;
memcpy(&kctl.id, &info->id, sizeof(info->id));
kctl.count = info->owner ? info->owner : 1;
access |= SNDRV_CTL_ELEM_ACCESS_USER;
kctl.info = snd_ctl_elem_user_info;
if (access & SNDRV_CTL_ELEM_ACCESS_READ)
kctl.get = snd_ctl_elem_user_get;
if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
kctl.put = snd_ctl_elem_user_put;
if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE) {
kctl.tlv.c = snd_ctl_elem_user_tlv;
access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
}
switch (info->type) {
case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
case SNDRV_CTL_ELEM_TYPE_INTEGER:
private_size = sizeof(long);
if (info->count > 128)
return -EINVAL;
break;
case SNDRV_CTL_ELEM_TYPE_INTEGER64:
private_size = sizeof(long long);
if (info->count > 64)
return -EINVAL;
break;
case SNDRV_CTL_ELEM_TYPE_BYTES:
private_size = sizeof(unsigned char);
if (info->count > 512)
return -EINVAL;
break;
case SNDRV_CTL_ELEM_TYPE_IEC958:
private_size = sizeof(struct snd_aes_iec958);
if (info->count != 1)
return -EINVAL;
break;
default:
return -EINVAL;
}
private_size *= info->count;
ue = kzalloc(sizeof(struct user_element) + private_size, GFP_KERNEL);
if (ue == NULL)
return -ENOMEM;
ue->info = *info;
ue->info.access = 0;
ue->elem_data = (char *)ue + sizeof(*ue);
ue->elem_data_size = private_size;
kctl.private_free = snd_ctl_elem_user_free;
_kctl = snd_ctl_new(&kctl, access);
if (_kctl == NULL) {
kfree(ue);
return -ENOMEM;
}
_kctl->private_data = ue;
for (idx = 0; idx < _kctl->count; idx++)
_kctl->vd[idx].owner = file;
err = snd_ctl_add(card, _kctl);
if (err < 0)
return err;
down_write(&card->controls_rwsem);
card->user_ctl_count++;
up_write(&card->controls_rwsem);
return 0;
}
static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
struct snd_ctl_elem_info __user *_info, int replace)
{
struct snd_ctl_elem_info info;
if (copy_from_user(&info, _info, sizeof(info)))
return -EFAULT;
return snd_ctl_elem_add(file, &info, replace);
}
static int snd_ctl_elem_remove(struct snd_ctl_file *file,
struct snd_ctl_elem_id __user *_id)
{
struct snd_ctl_elem_id id;
if (copy_from_user(&id, _id, sizeof(id)))
return -EFAULT;
return snd_ctl_remove_user_ctl(file, &id);
}
static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
{
int subscribe;
if (get_user(subscribe, ptr))
return -EFAULT;
if (subscribe < 0) {
subscribe = file->subscribed;
if (put_user(subscribe, ptr))
return -EFAULT;
return 0;
}
if (subscribe) {
file->subscribed = 1;
return 0;
} else if (file->subscribed) {
snd_ctl_empty_read_queue(file);
file->subscribed = 0;
}
return 0;
}
static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
struct snd_ctl_tlv __user *_tlv,
int op_flag)
{
struct snd_card *card = file->card;
struct snd_ctl_tlv tlv;
struct snd_kcontrol *kctl;
struct snd_kcontrol_volatile *vd;
unsigned int len;
int err = 0;
if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
return -EFAULT;
if (tlv.length < sizeof(unsigned int) * 2)
return -EINVAL;
down_read(&card->controls_rwsem);
kctl = snd_ctl_find_numid(card, tlv.numid);
if (kctl == NULL) {
err = -ENOENT;
goto __kctl_end;
}
if (kctl->tlv.p == NULL) {
err = -ENXIO;
goto __kctl_end;
}
vd = &kctl->vd[tlv.numid - kctl->id.numid];
if ((op_flag == 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||
(op_flag > 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||
(op_flag < 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0)) {
err = -ENXIO;
goto __kctl_end;
}
if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
if (vd->owner != NULL && vd->owner != file) {
err = -EPERM;
goto __kctl_end;
}
err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv);
if (err > 0) {
up_read(&card->controls_rwsem);
snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &kctl->id);
return 0;
}
} else {
if (op_flag) {
err = -ENXIO;
goto __kctl_end;
}
len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);
if (tlv.length < len) {
err = -ENOMEM;
goto __kctl_end;
}
if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))
err = -EFAULT;
}
__kctl_end:
up_read(&card->controls_rwsem);
return err;
}
static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct snd_ctl_file *ctl;
struct snd_card *card;
struct snd_kctl_ioctl *p;
void __user *argp = (void __user *)arg;
int __user *ip = argp;
int err;
ctl = file->private_data;
card = ctl->card;
if (snd_BUG_ON(!card))
return -ENXIO;
switch (cmd) {
case SNDRV_CTL_IOCTL_PVERSION:
return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
case SNDRV_CTL_IOCTL_CARD_INFO:
return snd_ctl_card_info(card, ctl, cmd, argp);
case SNDRV_CTL_IOCTL_ELEM_LIST:
return snd_ctl_elem_list(card, argp);
case SNDRV_CTL_IOCTL_ELEM_INFO:
return snd_ctl_elem_info_user(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_READ:
return snd_ctl_elem_read_user(card, argp);
case SNDRV_CTL_IOCTL_ELEM_WRITE:
return snd_ctl_elem_write_user(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_LOCK:
return snd_ctl_elem_lock(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
return snd_ctl_elem_unlock(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_ADD:
return snd_ctl_elem_add_user(ctl, argp, 0);
case SNDRV_CTL_IOCTL_ELEM_REPLACE:
return snd_ctl_elem_add_user(ctl, argp, 1);
case SNDRV_CTL_IOCTL_ELEM_REMOVE:
return snd_ctl_elem_remove(ctl, argp);
case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
return snd_ctl_subscribe_events(ctl, ip);
case SNDRV_CTL_IOCTL_TLV_READ:
return snd_ctl_tlv_ioctl(ctl, argp, 0);
case SNDRV_CTL_IOCTL_TLV_WRITE:
return snd_ctl_tlv_ioctl(ctl, argp, 1);
case SNDRV_CTL_IOCTL_TLV_COMMAND:
return snd_ctl_tlv_ioctl(ctl, argp, -1);
case SNDRV_CTL_IOCTL_POWER:
return -ENOPROTOOPT;
case SNDRV_CTL_IOCTL_POWER_STATE:
#ifdef CONFIG_PM
return put_user(card->power_state, ip) ? -EFAULT : 0;
#else
return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
#endif
}
down_read(&snd_ioctl_rwsem);
list_for_each_entry(p, &snd_control_ioctls, list) {
err = p->fioctl(card, ctl, cmd, arg);
if (err != -ENOIOCTLCMD) {
up_read(&snd_ioctl_rwsem);
return err;
}
}
up_read(&snd_ioctl_rwsem);
snd_printdd("unknown ioctl = 0x%x\n", cmd);
return -ENOTTY;
}
static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
size_t count, loff_t * offset)
{
struct snd_ctl_file *ctl;
int err = 0;
ssize_t result = 0;
ctl = file->private_data;
if (snd_BUG_ON(!ctl || !ctl->card))
return -ENXIO;
if (!ctl->subscribed)
return -EBADFD;
if (count < sizeof(struct snd_ctl_event))
return -EINVAL;
spin_lock_irq(&ctl->read_lock);
while (count >= sizeof(struct snd_ctl_event)) {
struct snd_ctl_event ev;
struct snd_kctl_event *kev;
while (list_empty(&ctl->events)) {
wait_queue_t wait;
if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
err = -EAGAIN;
goto __end_lock;
}
init_waitqueue_entry(&wait, current);
add_wait_queue(&ctl->change_sleep, &wait);
set_current_state(TASK_INTERRUPTIBLE);
spin_unlock_irq(&ctl->read_lock);
schedule();
remove_wait_queue(&ctl->change_sleep, &wait);
if (signal_pending(current))
return -ERESTARTSYS;
spin_lock_irq(&ctl->read_lock);
}
kev = snd_kctl_event(ctl->events.next);
ev.type = SNDRV_CTL_EVENT_ELEM;
ev.data.elem.mask = kev->mask;
ev.data.elem.id = kev->id;
list_del(&kev->list);
spin_unlock_irq(&ctl->read_lock);
kfree(kev);
if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
err = -EFAULT;
goto __end;
}
spin_lock_irq(&ctl->read_lock);
buffer += sizeof(struct snd_ctl_event);
count -= sizeof(struct snd_ctl_event);
result += sizeof(struct snd_ctl_event);
}
__end_lock:
spin_unlock_irq(&ctl->read_lock);
__end:
return result > 0 ? result : err;
}
static unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
{
unsigned int mask;
struct snd_ctl_file *ctl;
ctl = file->private_data;
if (!ctl->subscribed)
return 0;
poll_wait(file, &ctl->change_sleep, wait);
mask = 0;
if (!list_empty(&ctl->events))
mask |= POLLIN | POLLRDNORM;
return mask;
}
/*
* register the device-specific control-ioctls.
* called from each device manager like pcm.c, hwdep.c, etc.
*/
static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
{
struct snd_kctl_ioctl *pn;
pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
if (pn == NULL)
return -ENOMEM;
pn->fioctl = fcn;
down_write(&snd_ioctl_rwsem);
list_add_tail(&pn->list, lists);
up_write(&snd_ioctl_rwsem);
return 0;
}
int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
{
return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
}
EXPORT_SYMBOL(snd_ctl_register_ioctl);
#ifdef CONFIG_COMPAT
int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
{
return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
}
EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
#endif
/*
* de-register the device-specific control-ioctls.
*/
static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
struct list_head *lists)
{
struct snd_kctl_ioctl *p;
if (snd_BUG_ON(!fcn))
return -EINVAL;
down_write(&snd_ioctl_rwsem);
list_for_each_entry(p, lists, list) {
if (p->fioctl == fcn) {
list_del(&p->list);
up_write(&snd_ioctl_rwsem);
kfree(p);
return 0;
}
}
up_write(&snd_ioctl_rwsem);
snd_BUG();
return -EINVAL;
}
int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
{
return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
}
EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
#ifdef CONFIG_COMPAT
int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
{
return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
}
EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
#endif
static int snd_ctl_fasync(int fd, struct file * file, int on)
{
struct snd_ctl_file *ctl;
ctl = file->private_data;
return fasync_helper(fd, file, on, &ctl->fasync);
}
/*
* ioctl32 compat
*/
#ifdef CONFIG_COMPAT
#include "control_compat.c"
#else
#define snd_ctl_ioctl_compat NULL
#endif
/*
* INIT PART
*/
static const struct file_operations snd_ctl_f_ops =
{
.owner = THIS_MODULE,
.read = snd_ctl_read,
.open = snd_ctl_open,
.release = snd_ctl_release,
.llseek = no_llseek,
.poll = snd_ctl_poll,
.unlocked_ioctl = snd_ctl_ioctl,
.compat_ioctl = snd_ctl_ioctl_compat,
.fasync = snd_ctl_fasync,
};
/*
* registration of the control device
*/
static int snd_ctl_dev_register(struct snd_device *device)
{
struct snd_card *card = device->device_data;
int err, cardnum;
char name[16];
if (snd_BUG_ON(!card))
return -ENXIO;
cardnum = card->number;
if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
return -ENXIO;
sprintf(name, "controlC%i", cardnum);
if ((err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
&snd_ctl_f_ops, card, name)) < 0)
return err;
return 0;
}
/*
* disconnection of the control device
*/
static int snd_ctl_dev_disconnect(struct snd_device *device)
{
struct snd_card *card = device->device_data;
struct snd_ctl_file *ctl;
int err, cardnum;
if (snd_BUG_ON(!card))
return -ENXIO;
cardnum = card->number;
if (snd_BUG_ON(cardnum < 0 || cardnum >= SNDRV_CARDS))
return -ENXIO;
read_lock(&card->ctl_files_rwlock);
list_for_each_entry(ctl, &card->ctl_files, list) {
wake_up(&ctl->change_sleep);
kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
}
read_unlock(&card->ctl_files_rwlock);
if ((err = snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL,
card, -1)) < 0)
return err;
return 0;
}
/*
* free all controls
*/
static int snd_ctl_dev_free(struct snd_device *device)
{
struct snd_card *card = device->device_data;
struct snd_kcontrol *control;
down_write(&card->controls_rwsem);
while (!list_empty(&card->controls)) {
control = snd_kcontrol(card->controls.next);
snd_ctl_remove(card, control);
}
up_write(&card->controls_rwsem);
return 0;
}
/*
* create control core:
* called from init.c
*/
int snd_ctl_create(struct snd_card *card)
{
static struct snd_device_ops ops = {
.dev_free = snd_ctl_dev_free,
.dev_register = snd_ctl_dev_register,
.dev_disconnect = snd_ctl_dev_disconnect,
};
if (snd_BUG_ON(!card))
return -ENXIO;
return snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
}
/*
* Frequently used control callbacks/helpers
*/
int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_info *uinfo)
{
uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
uinfo->count = 1;
uinfo->value.integer.min = 0;
uinfo->value.integer.max = 1;
return 0;
}
EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_info *uinfo)
{
uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
uinfo->count = 2;
uinfo->value.integer.min = 0;
uinfo->value.integer.max = 1;
return 0;
}
EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
/**
* snd_ctl_enum_info - fills the info structure for an enumerated control
* @info: the structure to be filled
* @channels: the number of the control's channels; often one
* @items: the number of control values; also the size of @names
* @names: an array containing the names of all control values
*
* Sets all required fields in @info to their appropriate values.
* If the control's accessibility is not the default (readable and writable),
* the caller has to fill @info->access.
*/
int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
unsigned int items, const char *const names[])
{
info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
info->count = channels;
info->value.enumerated.items = items;
if (info->value.enumerated.item >= items)
info->value.enumerated.item = items - 1;
strlcpy(info->value.enumerated.name,
names[info->value.enumerated.item],
sizeof(info->value.enumerated.name));
return 0;
}
EXPORT_SYMBOL(snd_ctl_enum_info);
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