linux/sound/virtio/virtio_kctl.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * virtio-snd: Virtio sound device
 * Copyright (C) 2022 OpenSynergy GmbH
 */
#include <sound/control.h>
#include <linux/virtio_config.h>

#include "virtio_card.h"

/* Map for converting VirtIO types to ALSA types. */
static const snd_ctl_elem_type_t g_v2a_type_map[] = …;

/* Map for converting VirtIO access rights to ALSA access rights. */
static const unsigned int g_v2a_access_map[] = …;

/* Map for converting VirtIO event masks to ALSA event masks. */
static const unsigned int g_v2a_mask_map[] = …;

/**
 * virtsnd_kctl_info() - Returns information about the control.
 * @kcontrol: ALSA control element.
 * @uinfo: Element information.
 *
 * Context: Process context.
 * Return: 0 on success, -errno on failure.
 */
static int virtsnd_kctl_info(struct snd_kcontrol *kcontrol,
			     struct snd_ctl_elem_info *uinfo)
{ … }

/**
 * virtsnd_kctl_get() - Read the value from the control.
 * @kcontrol: ALSA control element.
 * @uvalue: Element value.
 *
 * Context: Process context.
 * Return: 0 on success, -errno on failure.
 */
static int virtsnd_kctl_get(struct snd_kcontrol *kcontrol,
			    struct snd_ctl_elem_value *uvalue)
{ … }

/**
 * virtsnd_kctl_put() - Write the value to the control.
 * @kcontrol: ALSA control element.
 * @uvalue: Element value.
 *
 * Context: Process context.
 * Return: 0 on success, -errno on failure.
 */
static int virtsnd_kctl_put(struct snd_kcontrol *kcontrol,
			    struct snd_ctl_elem_value *uvalue)
{ … }

/**
 * virtsnd_kctl_tlv_op() - Perform an operation on the control's metadata.
 * @kcontrol: ALSA control element.
 * @op_flag: Operation code (SNDRV_CTL_TLV_OP_XXX).
 * @size: Size of the TLV data in bytes.
 * @utlv: TLV data.
 *
 * Context: Process context.
 * Return: 0 on success, -errno on failure.
 */
static int virtsnd_kctl_tlv_op(struct snd_kcontrol *kcontrol, int op_flag,
			       unsigned int size, unsigned int __user *utlv)
{ … }

/**
 * virtsnd_kctl_get_enum_items() - Query items for the ENUMERATED element type.
 * @snd: VirtIO sound device.
 * @cid: Control element ID.
 *
 * This function is called during initial device initialization.
 *
 * Context: Any context that permits to sleep.
 * Return: 0 on success, -errno on failure.
 */
static int virtsnd_kctl_get_enum_items(struct virtio_snd *snd, unsigned int cid)
{ … }

/**
 * virtsnd_kctl_parse_cfg() - Parse the control element configuration.
 * @snd: VirtIO sound device.
 *
 * This function is called during initial device initialization.
 *
 * Context: Any context that permits to sleep.
 * Return: 0 on success, -errno on failure.
 */
int virtsnd_kctl_parse_cfg(struct virtio_snd *snd)
{ … }

/**
 * virtsnd_kctl_build_devs() - Build ALSA control elements.
 * @snd: VirtIO sound device.
 *
 * Context: Any context that permits to sleep.
 * Return: 0 on success, -errno on failure.
 */
int virtsnd_kctl_build_devs(struct virtio_snd *snd)
{ … }

/**
 * virtsnd_kctl_event() - Handle the control element event notification.
 * @snd: VirtIO sound device.
 * @event: VirtIO sound event.
 *
 * Context: Interrupt context.
 */
void virtsnd_kctl_event(struct virtio_snd *snd, struct virtio_snd_event *event)
{ … }