sound/virtio/virtio_kctl.c - linux - Git at Google

 // 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[] = {
 	[VIRTIO_SND_CTL_TYPE_BOOLEAN] = SNDRV_CTL_ELEM_TYPE_BOOLEAN,
 	[VIRTIO_SND_CTL_TYPE_INTEGER] = SNDRV_CTL_ELEM_TYPE_INTEGER,
 	[VIRTIO_SND_CTL_TYPE_INTEGER64] = SNDRV_CTL_ELEM_TYPE_INTEGER64,
 	[VIRTIO_SND_CTL_TYPE_ENUMERATED] = SNDRV_CTL_ELEM_TYPE_ENUMERATED,
 	[VIRTIO_SND_CTL_TYPE_BYTES] = SNDRV_CTL_ELEM_TYPE_BYTES,
 	[VIRTIO_SND_CTL_TYPE_IEC958] = SNDRV_CTL_ELEM_TYPE_IEC958
 };

 /* Map for converting VirtIO access rights to ALSA access rights. */
 static const unsigned int g_v2a_access_map[] = {
 	[VIRTIO_SND_CTL_ACCESS_READ] = SNDRV_CTL_ELEM_ACCESS_READ,
 	[VIRTIO_SND_CTL_ACCESS_WRITE] = SNDRV_CTL_ELEM_ACCESS_WRITE,
 	[VIRTIO_SND_CTL_ACCESS_VOLATILE] = SNDRV_CTL_ELEM_ACCESS_VOLATILE,
 	[VIRTIO_SND_CTL_ACCESS_INACTIVE] = SNDRV_CTL_ELEM_ACCESS_INACTIVE,
 	[VIRTIO_SND_CTL_ACCESS_TLV_READ] = SNDRV_CTL_ELEM_ACCESS_TLV_READ,
 	[VIRTIO_SND_CTL_ACCESS_TLV_WRITE] = SNDRV_CTL_ELEM_ACCESS_TLV_WRITE,
 	[VIRTIO_SND_CTL_ACCESS_TLV_COMMAND] = SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND
 };

 /* Map for converting VirtIO event masks to ALSA event masks. */
 static const unsigned int g_v2a_mask_map[] = {
 	[VIRTIO_SND_CTL_EVT_MASK_VALUE] = SNDRV_CTL_EVENT_MASK_VALUE,
 	[VIRTIO_SND_CTL_EVT_MASK_INFO] = SNDRV_CTL_EVENT_MASK_INFO,
 	[VIRTIO_SND_CTL_EVT_MASK_TLV] = SNDRV_CTL_EVENT_MASK_TLV
 };

 /**
  * 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)
 {
 	struct virtio_snd *snd = kcontrol->private_data;
 	struct virtio_kctl *kctl = &snd->kctls[kcontrol->private_value];
 	struct virtio_snd_ctl_info *kinfo =
 		&snd->kctl_infos[kcontrol->private_value];
 	unsigned int i;

 	uinfo->type = g_v2a_type_map[le32_to_cpu(kinfo->type)];
 	uinfo->count = le32_to_cpu(kinfo->count);

 	switch (uinfo->type) {
 	case SNDRV_CTL_ELEM_TYPE_INTEGER:
 		uinfo->value.integer.min =
 			le32_to_cpu(kinfo->value.integer.min);
 		uinfo->value.integer.max =
 			le32_to_cpu(kinfo->value.integer.max);
 		uinfo->value.integer.step =
 			le32_to_cpu(kinfo->value.integer.step);

 		break;
 	case SNDRV_CTL_ELEM_TYPE_INTEGER64:
 		uinfo->value.integer64.min =
 			le64_to_cpu(kinfo->value.integer64.min);
 		uinfo->value.integer64.max =
 			le64_to_cpu(kinfo->value.integer64.max);
 		uinfo->value.integer64.step =
 			le64_to_cpu(kinfo->value.integer64.step);

 		break;
 	case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
 		uinfo->value.enumerated.items =
 			le32_to_cpu(kinfo->value.enumerated.items);
 		i = uinfo->value.enumerated.item;
 		if (i >= uinfo->value.enumerated.items)
 			return -EINVAL;

 		strscpy(uinfo->value.enumerated.name, kctl->items[i].item,
 			sizeof(uinfo->value.enumerated.name));

 		break;
 	}

 	return 0;
 }

 /**
  * 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)
 {
 	struct virtio_snd *snd = kcontrol->private_data;
 	struct virtio_snd_ctl_info *kinfo =
 		&snd->kctl_infos[kcontrol->private_value];
 	unsigned int type = le32_to_cpu(kinfo->type);
 	unsigned int count = le32_to_cpu(kinfo->count);
 	struct virtio_snd_msg *msg;
 	struct virtio_snd_ctl_hdr *hdr;
 	struct virtio_snd_ctl_value *kvalue;
 	size_t request_size = sizeof(*hdr);
 	size_t response_size = sizeof(struct virtio_snd_hdr) + sizeof(*kvalue);
 	unsigned int i;
 	int rc;

 	msg = virtsnd_ctl_msg_alloc(request_size, response_size, GFP_KERNEL);
 	if (!msg)
 		return -ENOMEM;

 	virtsnd_ctl_msg_ref(msg);

 	hdr = virtsnd_ctl_msg_request(msg);
 	hdr->hdr.code = cpu_to_le32(VIRTIO_SND_R_CTL_READ);
 	hdr->control_id = cpu_to_le32(kcontrol->private_value);

 	rc = virtsnd_ctl_msg_send_sync(snd, msg);
 	if (rc)
 		goto on_failure;

 	kvalue = (void *)((u8 *)virtsnd_ctl_msg_response(msg) +
 			  sizeof(struct virtio_snd_hdr));

 	switch (type) {
 	case VIRTIO_SND_CTL_TYPE_BOOLEAN:
 	case VIRTIO_SND_CTL_TYPE_INTEGER:
 		for (i = 0; i < count; ++i)
 			uvalue->value.integer.value[i] =
 				le32_to_cpu(kvalue->value.integer[i]);
 		break;
 	case VIRTIO_SND_CTL_TYPE_INTEGER64:
 		for (i = 0; i < count; ++i)
 			uvalue->value.integer64.value[i] =
 				le64_to_cpu(kvalue->value.integer64[i]);
 		break;
 	case VIRTIO_SND_CTL_TYPE_ENUMERATED:
 		for (i = 0; i < count; ++i)
 			uvalue->value.enumerated.item[i] =
 				le32_to_cpu(kvalue->value.enumerated[i]);
 		break;
 	case VIRTIO_SND_CTL_TYPE_BYTES:
 		memcpy(uvalue->value.bytes.data, kvalue->value.bytes, count);
 		break;
 	case VIRTIO_SND_CTL_TYPE_IEC958:
 		memcpy(&uvalue->value.iec958, &kvalue->value.iec958,
 		       sizeof(uvalue->value.iec958));
 		break;
 	}

 on_failure:
 	virtsnd_ctl_msg_unref(msg);

 	return rc;
 }

 /**
  * 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)
 {
 	struct virtio_snd *snd = kcontrol->private_data;
 	struct virtio_snd_ctl_info *kinfo =
 		&snd->kctl_infos[kcontrol->private_value];
 	unsigned int type = le32_to_cpu(kinfo->type);
 	unsigned int count = le32_to_cpu(kinfo->count);
 	struct virtio_snd_msg *msg;
 	struct virtio_snd_ctl_hdr *hdr;
 	struct virtio_snd_ctl_value *kvalue;
 	size_t request_size = sizeof(*hdr) + sizeof(*kvalue);
 	size_t response_size = sizeof(struct virtio_snd_hdr);
 	unsigned int i;

 	msg = virtsnd_ctl_msg_alloc(request_size, response_size, GFP_KERNEL);
 	if (!msg)
 		return -ENOMEM;

 	hdr = virtsnd_ctl_msg_request(msg);
 	hdr->hdr.code = cpu_to_le32(VIRTIO_SND_R_CTL_WRITE);
 	hdr->control_id = cpu_to_le32(kcontrol->private_value);

 	kvalue = (void *)((u8 *)hdr + sizeof(*hdr));

 	switch (type) {
 	case VIRTIO_SND_CTL_TYPE_BOOLEAN:
 	case VIRTIO_SND_CTL_TYPE_INTEGER:
 		for (i = 0; i < count; ++i)
 			kvalue->value.integer[i] =
 				cpu_to_le32(uvalue->value.integer.value[i]);
 		break;
 	case VIRTIO_SND_CTL_TYPE_INTEGER64:
 		for (i = 0; i < count; ++i)
 			kvalue->value.integer64[i] =
 				cpu_to_le64(uvalue->value.integer64.value[i]);
 		break;
 	case VIRTIO_SND_CTL_TYPE_ENUMERATED:
 		for (i = 0; i < count; ++i)
 			kvalue->value.enumerated[i] =
 				cpu_to_le32(uvalue->value.enumerated.item[i]);
 		break;
 	case VIRTIO_SND_CTL_TYPE_BYTES:
 		memcpy(kvalue->value.bytes, uvalue->value.bytes.data, count);
 		break;
 	case VIRTIO_SND_CTL_TYPE_IEC958:
 		memcpy(&kvalue->value.iec958, &uvalue->value.iec958,
 		       sizeof(kvalue->value.iec958));
 		break;
 	}

 	return virtsnd_ctl_msg_send_sync(snd, msg);
 }

 /**
  * 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)
 {
 	struct virtio_snd *snd = kcontrol->private_data;
 	struct virtio_snd_msg *msg;
 	struct virtio_snd_ctl_hdr *hdr;
 	unsigned int *tlv;
 	struct scatterlist sg;
 	int rc;

 	msg = virtsnd_ctl_msg_alloc(sizeof(*hdr), sizeof(struct virtio_snd_hdr),
 				    GFP_KERNEL);
 	if (!msg)
 		return -ENOMEM;

 	tlv = kzalloc(size, GFP_KERNEL);
 	if (!tlv) {
 		rc = -ENOMEM;
 		goto on_msg_unref;
 	}

 	sg_init_one(&sg, tlv, size);

 	hdr = virtsnd_ctl_msg_request(msg);
 	hdr->control_id = cpu_to_le32(kcontrol->private_value);

 	switch (op_flag) {
 	case SNDRV_CTL_TLV_OP_READ:
 		hdr->hdr.code = cpu_to_le32(VIRTIO_SND_R_CTL_TLV_READ);

 		rc = virtsnd_ctl_msg_send(snd, msg, NULL, &sg, false);
 		if (!rc) {
 			if (copy_to_user(utlv, tlv, size))
 				rc = -EFAULT;
 		}

 		break;
 	case SNDRV_CTL_TLV_OP_WRITE:
 	case SNDRV_CTL_TLV_OP_CMD:
 		if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
 			hdr->hdr.code = cpu_to_le32(VIRTIO_SND_R_CTL_TLV_WRITE);
 		else
 			hdr->hdr.code =
 				cpu_to_le32(VIRTIO_SND_R_CTL_TLV_COMMAND);

 		if (copy_from_user(tlv, utlv, size)) {
 			rc = -EFAULT;
 			goto on_msg_unref;
 		} else {
 			rc = virtsnd_ctl_msg_send(snd, msg, &sg, NULL, false);
 		}

 		break;
 	default:
 		rc = -EINVAL;
 		/* We never get here - we listed all values for op_flag */
 		WARN_ON(1);
 		goto on_msg_unref;
 	}
 	kfree(tlv);
 	return rc;

 on_msg_unref:
 	virtsnd_ctl_msg_unref(msg);
 	kfree(tlv);

 	return rc;
 }

 /**
  * 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)
 {
 	struct virtio_device *vdev = snd->vdev;
 	struct virtio_snd_ctl_info *kinfo = &snd->kctl_infos[cid];
 	struct virtio_kctl *kctl = &snd->kctls[cid];
 	struct virtio_snd_msg *msg;
 	struct virtio_snd_ctl_hdr *hdr;
 	unsigned int n = le32_to_cpu(kinfo->value.enumerated.items);
 	struct scatterlist sg;

 	msg = virtsnd_ctl_msg_alloc(sizeof(*hdr),
 				    sizeof(struct virtio_snd_hdr), GFP_KERNEL);
 	if (!msg)
 		return -ENOMEM;

 	kctl->items = devm_kcalloc(&vdev->dev, n, sizeof(*kctl->items),
 				   GFP_KERNEL);
 	if (!kctl->items) {
 		virtsnd_ctl_msg_unref(msg);
 		return -ENOMEM;
 	}

 	sg_init_one(&sg, kctl->items, n * sizeof(*kctl->items));

 	hdr = virtsnd_ctl_msg_request(msg);
 	hdr->hdr.code = cpu_to_le32(VIRTIO_SND_R_CTL_ENUM_ITEMS);
 	hdr->control_id = cpu_to_le32(cid);

 	return virtsnd_ctl_msg_send(snd, msg, NULL, &sg, false);
 }

 /**
  * 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)
 {
 	struct virtio_device *vdev = snd->vdev;
 	u32 i;
 	int rc;

 	virtio_cread_le(vdev, struct virtio_snd_config, controls,
 			&snd->nkctls);
 	if (!snd->nkctls)
 		return 0;

 	snd->kctl_infos = devm_kcalloc(&vdev->dev, snd->nkctls,
 				       sizeof(*snd->kctl_infos), GFP_KERNEL);
 	if (!snd->kctl_infos)
 		return -ENOMEM;

 	snd->kctls = devm_kcalloc(&vdev->dev, snd->nkctls, sizeof(*snd->kctls),
 				  GFP_KERNEL);
 	if (!snd->kctls)
 		return -ENOMEM;

 	rc = virtsnd_ctl_query_info(snd, VIRTIO_SND_R_CTL_INFO, 0, snd->nkctls,
 				    sizeof(*snd->kctl_infos), snd->kctl_infos);
 	if (rc)
 		return rc;

 	for (i = 0; i < snd->nkctls; ++i) {
 		struct virtio_snd_ctl_info *kinfo = &snd->kctl_infos[i];
 		unsigned int type = le32_to_cpu(kinfo->type);

 		if (type == VIRTIO_SND_CTL_TYPE_ENUMERATED) {
 			rc = virtsnd_kctl_get_enum_items(snd, i);
 			if (rc)
 				return rc;
 		}
 	}

 	return 0;
 }

 /**
  * 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)
 {
 	unsigned int cid;

 	for (cid = 0; cid < snd->nkctls; ++cid) {
 		struct virtio_snd_ctl_info *kinfo = &snd->kctl_infos[cid];
 		struct virtio_kctl *kctl = &snd->kctls[cid];
 		struct snd_kcontrol_new kctl_new;
 		unsigned int i;
 		int rc;

 		memset(&kctl_new, 0, sizeof(kctl_new));

 		kctl_new.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
 		kctl_new.name = kinfo->name;
 		kctl_new.index = le32_to_cpu(kinfo->index);

 		for (i = 0; i < ARRAY_SIZE(g_v2a_access_map); ++i)
 			if (le32_to_cpu(kinfo->access) & (1 << i))
 				kctl_new.access |= g_v2a_access_map[i];

 		if (kctl_new.access & (SNDRV_CTL_ELEM_ACCESS_TLV_READ |
 				       SNDRV_CTL_ELEM_ACCESS_TLV_WRITE |
 				       SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND)) {
 			kctl_new.access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
 			kctl_new.tlv.c = virtsnd_kctl_tlv_op;
 		}

 		kctl_new.info = virtsnd_kctl_info;
 		kctl_new.get = virtsnd_kctl_get;
 		kctl_new.put = virtsnd_kctl_put;
 		kctl_new.private_value = cid;

 		kctl->kctl = snd_ctl_new1(&kctl_new, snd);
 		if (!kctl->kctl)
 			return -ENOMEM;

 		rc = snd_ctl_add(snd->card, kctl->kctl);
 		if (rc)
 			return rc;
 	}

 	return 0;
 }

 /**
  * 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)
 {
 	struct virtio_snd_ctl_event *kevent =
 		(struct virtio_snd_ctl_event *)event;
 	struct virtio_kctl *kctl;
 	unsigned int cid = le16_to_cpu(kevent->control_id);
 	unsigned int mask = 0;
 	unsigned int i;

 	if (cid >= snd->nkctls)
 		return;

 	for (i = 0; i < ARRAY_SIZE(g_v2a_mask_map); ++i)
 		if (le16_to_cpu(kevent->mask) & (1 << i))
 			mask |= g_v2a_mask_map[i];


 	kctl = &snd->kctls[cid];

 	snd_ctl_notify(snd->card, mask, &kctl->kctl->id);
 }
	// 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[] = {
	[VIRTIO_SND_CTL_TYPE_BOOLEAN] = SNDRV_CTL_ELEM_TYPE_BOOLEAN,
	[VIRTIO_SND_CTL_TYPE_INTEGER] = SNDRV_CTL_ELEM_TYPE_INTEGER,
	[VIRTIO_SND_CTL_TYPE_INTEGER64] = SNDRV_CTL_ELEM_TYPE_INTEGER64,
	[VIRTIO_SND_CTL_TYPE_ENUMERATED] = SNDRV_CTL_ELEM_TYPE_ENUMERATED,
	[VIRTIO_SND_CTL_TYPE_BYTES] = SNDRV_CTL_ELEM_TYPE_BYTES,
	[VIRTIO_SND_CTL_TYPE_IEC958] = SNDRV_CTL_ELEM_TYPE_IEC958
	};

	/* Map for converting VirtIO access rights to ALSA access rights. */
	static const unsigned int g_v2a_access_map[] = {
	[VIRTIO_SND_CTL_ACCESS_READ] = SNDRV_CTL_ELEM_ACCESS_READ,
	[VIRTIO_SND_CTL_ACCESS_WRITE] = SNDRV_CTL_ELEM_ACCESS_WRITE,
	[VIRTIO_SND_CTL_ACCESS_VOLATILE] = SNDRV_CTL_ELEM_ACCESS_VOLATILE,
	[VIRTIO_SND_CTL_ACCESS_INACTIVE] = SNDRV_CTL_ELEM_ACCESS_INACTIVE,
	[VIRTIO_SND_CTL_ACCESS_TLV_READ] = SNDRV_CTL_ELEM_ACCESS_TLV_READ,
	[VIRTIO_SND_CTL_ACCESS_TLV_WRITE] = SNDRV_CTL_ELEM_ACCESS_TLV_WRITE,
	[VIRTIO_SND_CTL_ACCESS_TLV_COMMAND] = SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND
	};

	/* Map for converting VirtIO event masks to ALSA event masks. */
	static const unsigned int g_v2a_mask_map[] = {
	[VIRTIO_SND_CTL_EVT_MASK_VALUE] = SNDRV_CTL_EVENT_MASK_VALUE,
	[VIRTIO_SND_CTL_EVT_MASK_INFO] = SNDRV_CTL_EVENT_MASK_INFO,
	[VIRTIO_SND_CTL_EVT_MASK_TLV] = SNDRV_CTL_EVENT_MASK_TLV
	};

	/**
	* 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)
	{
	struct virtio_snd *snd = kcontrol->private_data;
	struct virtio_kctl *kctl = &snd->kctls[kcontrol->private_value];
	struct virtio_snd_ctl_info *kinfo =
	&snd->kctl_infos[kcontrol->private_value];
	unsigned int i;

	uinfo->type = g_v2a_type_map[le32_to_cpu(kinfo->type)];
	uinfo->count = le32_to_cpu(kinfo->count);

	switch (uinfo->type) {
	case SNDRV_CTL_ELEM_TYPE_INTEGER:
	uinfo->value.integer.min =
	le32_to_cpu(kinfo->value.integer.min);
	uinfo->value.integer.max =
	le32_to_cpu(kinfo->value.integer.max);
	uinfo->value.integer.step =
	le32_to_cpu(kinfo->value.integer.step);

	break;
	case SNDRV_CTL_ELEM_TYPE_INTEGER64:
	uinfo->value.integer64.min =
	le64_to_cpu(kinfo->value.integer64.min);
	uinfo->value.integer64.max =
	le64_to_cpu(kinfo->value.integer64.max);
	uinfo->value.integer64.step =
	le64_to_cpu(kinfo->value.integer64.step);

	break;
	case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
	uinfo->value.enumerated.items =
	le32_to_cpu(kinfo->value.enumerated.items);
	i = uinfo->value.enumerated.item;
	if (i >= uinfo->value.enumerated.items)
	return -EINVAL;

	strscpy(uinfo->value.enumerated.name, kctl->items[i].item,
	sizeof(uinfo->value.enumerated.name));

	break;
	}

	return 0;
	}

	/**
	* 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)
	{
	struct virtio_snd *snd = kcontrol->private_data;
	struct virtio_snd_ctl_info *kinfo =
	&snd->kctl_infos[kcontrol->private_value];
	unsigned int type = le32_to_cpu(kinfo->type);
	unsigned int count = le32_to_cpu(kinfo->count);
	struct virtio_snd_msg *msg;
	struct virtio_snd_ctl_hdr *hdr;
	struct virtio_snd_ctl_value *kvalue;
	size_t request_size = sizeof(*hdr);
	size_t response_size = sizeof(struct virtio_snd_hdr) + sizeof(*kvalue);
	unsigned int i;
	int rc;

	msg = virtsnd_ctl_msg_alloc(request_size, response_size, GFP_KERNEL);
	if (!msg)
	return -ENOMEM;

	virtsnd_ctl_msg_ref(msg);

	hdr = virtsnd_ctl_msg_request(msg);
	hdr->hdr.code = cpu_to_le32(VIRTIO_SND_R_CTL_READ);
	hdr->control_id = cpu_to_le32(kcontrol->private_value);

	rc = virtsnd_ctl_msg_send_sync(snd, msg);
	if (rc)
	goto on_failure;

	kvalue = (void )((u8 )virtsnd_ctl_msg_response(msg) +
	sizeof(struct virtio_snd_hdr));

	switch (type) {
	case VIRTIO_SND_CTL_TYPE_BOOLEAN:
	case VIRTIO_SND_CTL_TYPE_INTEGER:
	for (i = 0; i < count; ++i)
	uvalue->value.integer.value[i] =
	le32_to_cpu(kvalue->value.integer[i]);
	break;
	case VIRTIO_SND_CTL_TYPE_INTEGER64:
	for (i = 0; i < count; ++i)
	uvalue->value.integer64.value[i] =
	le64_to_cpu(kvalue->value.integer64[i]);
	break;
	case VIRTIO_SND_CTL_TYPE_ENUMERATED:
	for (i = 0; i < count; ++i)
	uvalue->value.enumerated.item[i] =
	le32_to_cpu(kvalue->value.enumerated[i]);
	break;
	case VIRTIO_SND_CTL_TYPE_BYTES:
	memcpy(uvalue->value.bytes.data, kvalue->value.bytes, count);
	break;
	case VIRTIO_SND_CTL_TYPE_IEC958:
	memcpy(&uvalue->value.iec958, &kvalue->value.iec958,
	sizeof(uvalue->value.iec958));
	break;
	}

	on_failure:
	virtsnd_ctl_msg_unref(msg);

	return rc;
	}

	/**
	* 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)
	{
	struct virtio_snd *snd = kcontrol->private_data;
	struct virtio_snd_ctl_info *kinfo =
	&snd->kctl_infos[kcontrol->private_value];
	unsigned int type = le32_to_cpu(kinfo->type);
	unsigned int count = le32_to_cpu(kinfo->count);
	struct virtio_snd_msg *msg;
	struct virtio_snd_ctl_hdr *hdr;
	struct virtio_snd_ctl_value *kvalue;
	size_t request_size = sizeof(hdr) + sizeof(kvalue);
	size_t response_size = sizeof(struct virtio_snd_hdr);
	unsigned int i;

	msg = virtsnd_ctl_msg_alloc(request_size, response_size, GFP_KERNEL);
	if (!msg)
	return -ENOMEM;

	hdr = virtsnd_ctl_msg_request(msg);
	hdr->hdr.code = cpu_to_le32(VIRTIO_SND_R_CTL_WRITE);
	hdr->control_id = cpu_to_le32(kcontrol->private_value);

	kvalue = (void )((u8 )hdr + sizeof(*hdr));

	switch (type) {
	case VIRTIO_SND_CTL_TYPE_BOOLEAN:
	case VIRTIO_SND_CTL_TYPE_INTEGER:
	for (i = 0; i < count; ++i)
	kvalue->value.integer[i] =
	cpu_to_le32(uvalue->value.integer.value[i]);
	break;
	case VIRTIO_SND_CTL_TYPE_INTEGER64:
	for (i = 0; i < count; ++i)
	kvalue->value.integer64[i] =
	cpu_to_le64(uvalue->value.integer64.value[i]);
	break;
	case VIRTIO_SND_CTL_TYPE_ENUMERATED:
	for (i = 0; i < count; ++i)
	kvalue->value.enumerated[i] =
	cpu_to_le32(uvalue->value.enumerated.item[i]);
	break;
	case VIRTIO_SND_CTL_TYPE_BYTES:
	memcpy(kvalue->value.bytes, uvalue->value.bytes.data, count);
	break;
	case VIRTIO_SND_CTL_TYPE_IEC958:
	memcpy(&kvalue->value.iec958, &uvalue->value.iec958,
	sizeof(kvalue->value.iec958));
	break;
	}

	return virtsnd_ctl_msg_send_sync(snd, msg);
	}

	/**
	* 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)
	{
	struct virtio_snd *snd = kcontrol->private_data;
	struct virtio_snd_msg *msg;
	struct virtio_snd_ctl_hdr *hdr;
	unsigned int *tlv;
	struct scatterlist sg;
	int rc;

	msg = virtsnd_ctl_msg_alloc(sizeof(*hdr), sizeof(struct virtio_snd_hdr),
	GFP_KERNEL);
	if (!msg)
	return -ENOMEM;

	tlv = kzalloc(size, GFP_KERNEL);
	if (!tlv) {
	rc = -ENOMEM;
	goto on_msg_unref;
	}

	sg_init_one(&sg, tlv, size);

	hdr = virtsnd_ctl_msg_request(msg);
	hdr->control_id = cpu_to_le32(kcontrol->private_value);

	switch (op_flag) {
	case SNDRV_CTL_TLV_OP_READ:
	hdr->hdr.code = cpu_to_le32(VIRTIO_SND_R_CTL_TLV_READ);

	rc = virtsnd_ctl_msg_send(snd, msg, NULL, &sg, false);
	if (!rc) {
	if (copy_to_user(utlv, tlv, size))
	rc = -EFAULT;
	}

	break;
	case SNDRV_CTL_TLV_OP_WRITE:
	case SNDRV_CTL_TLV_OP_CMD:
	if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
	hdr->hdr.code = cpu_to_le32(VIRTIO_SND_R_CTL_TLV_WRITE);
	else
	hdr->hdr.code =
	cpu_to_le32(VIRTIO_SND_R_CTL_TLV_COMMAND);

	if (copy_from_user(tlv, utlv, size)) {
	rc = -EFAULT;
	goto on_msg_unref;
	} else {
	rc = virtsnd_ctl_msg_send(snd, msg, &sg, NULL, false);
	}

	break;
	default:
	rc = -EINVAL;
	/* We never get here - we listed all values for op_flag */
	WARN_ON(1);
	goto on_msg_unref;
	}
	kfree(tlv);
	return rc;

	on_msg_unref:
	virtsnd_ctl_msg_unref(msg);
	kfree(tlv);

	return rc;
	}

	/**
	* 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)
	{
	struct virtio_device *vdev = snd->vdev;
	struct virtio_snd_ctl_info *kinfo = &snd->kctl_infos[cid];
	struct virtio_kctl *kctl = &snd->kctls[cid];
	struct virtio_snd_msg *msg;
	struct virtio_snd_ctl_hdr *hdr;
	unsigned int n = le32_to_cpu(kinfo->value.enumerated.items);
	struct scatterlist sg;

	msg = virtsnd_ctl_msg_alloc(sizeof(*hdr),
	sizeof(struct virtio_snd_hdr), GFP_KERNEL);
	if (!msg)
	return -ENOMEM;

	kctl->items = devm_kcalloc(&vdev->dev, n, sizeof(*kctl->items),
	GFP_KERNEL);
	if (!kctl->items) {
	virtsnd_ctl_msg_unref(msg);
	return -ENOMEM;
	}

	sg_init_one(&sg, kctl->items, n * sizeof(*kctl->items));

	hdr = virtsnd_ctl_msg_request(msg);
	hdr->hdr.code = cpu_to_le32(VIRTIO_SND_R_CTL_ENUM_ITEMS);
	hdr->control_id = cpu_to_le32(cid);

	return virtsnd_ctl_msg_send(snd, msg, NULL, &sg, false);
	}

	/**
	* 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)
	{
	struct virtio_device *vdev = snd->vdev;
	u32 i;
	int rc;

	virtio_cread_le(vdev, struct virtio_snd_config, controls,
	&snd->nkctls);
	if (!snd->nkctls)
	return 0;

	snd->kctl_infos = devm_kcalloc(&vdev->dev, snd->nkctls,
	sizeof(*snd->kctl_infos), GFP_KERNEL);
	if (!snd->kctl_infos)
	return -ENOMEM;

	snd->kctls = devm_kcalloc(&vdev->dev, snd->nkctls, sizeof(*snd->kctls),
	GFP_KERNEL);
	if (!snd->kctls)
	return -ENOMEM;

	rc = virtsnd_ctl_query_info(snd, VIRTIO_SND_R_CTL_INFO, 0, snd->nkctls,
	sizeof(*snd->kctl_infos), snd->kctl_infos);
	if (rc)
	return rc;

	for (i = 0; i < snd->nkctls; ++i) {
	struct virtio_snd_ctl_info *kinfo = &snd->kctl_infos[i];
	unsigned int type = le32_to_cpu(kinfo->type);

	if (type == VIRTIO_SND_CTL_TYPE_ENUMERATED) {
	rc = virtsnd_kctl_get_enum_items(snd, i);
	if (rc)
	return rc;
	}
	}

	return 0;
	}

	/**
	* 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)
	{
	unsigned int cid;

	for (cid = 0; cid < snd->nkctls; ++cid) {
	struct virtio_snd_ctl_info *kinfo = &snd->kctl_infos[cid];
	struct virtio_kctl *kctl = &snd->kctls[cid];
	struct snd_kcontrol_new kctl_new;
	unsigned int i;
	int rc;

	memset(&kctl_new, 0, sizeof(kctl_new));

	kctl_new.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
	kctl_new.name = kinfo->name;
	kctl_new.index = le32_to_cpu(kinfo->index);

	for (i = 0; i < ARRAY_SIZE(g_v2a_access_map); ++i)
	if (le32_to_cpu(kinfo->access) & (1 << i))
	kctl_new.access \|= g_v2a_access_map[i];

	if (kctl_new.access & (SNDRV_CTL_ELEM_ACCESS_TLV_READ \|
	SNDRV_CTL_ELEM_ACCESS_TLV_WRITE \|
	SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND)) {
	kctl_new.access \|= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
	kctl_new.tlv.c = virtsnd_kctl_tlv_op;
	}

	kctl_new.info = virtsnd_kctl_info;
	kctl_new.get = virtsnd_kctl_get;
	kctl_new.put = virtsnd_kctl_put;
	kctl_new.private_value = cid;

	kctl->kctl = snd_ctl_new1(&kctl_new, snd);
	if (!kctl->kctl)
	return -ENOMEM;

	rc = snd_ctl_add(snd->card, kctl->kctl);
	if (rc)
	return rc;
	}

	return 0;
	}

	/**
	* 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)
	{
	struct virtio_snd_ctl_event *kevent =
	(struct virtio_snd_ctl_event *)event;
	struct virtio_kctl *kctl;
	unsigned int cid = le16_to_cpu(kevent->control_id);
	unsigned int mask = 0;
	unsigned int i;

	if (cid >= snd->nkctls)
	return;

	for (i = 0; i < ARRAY_SIZE(g_v2a_mask_map); ++i)
	if (le16_to_cpu(kevent->mask) & (1 << i))
	mask \|= g_v2a_mask_map[i];


	kctl = &snd->kctls[cid];

	snd_ctl_notify(snd->card, mask, &kctl->kctl->id);
	}