@@ -7,6 +7,14 @@
#include <linux/virtio_types.h>
+/*******************************************************************************
+ * FEATURE BITS
+ */
+enum {
+ /* device supports control elements */
+ VIRTIO_SND_F_CTLS = 0
+};
+
/*******************************************************************************
* CONFIGURATION SPACE
*/
@@ -17,6 +25,8 @@ struct virtio_snd_config {
__le32 streams;
/* # of available channel maps */
__le32 chmaps;
+ /* # of available control elements */
+ __le32 controls;
};
enum {
@@ -55,6 +65,15 @@ enum {
/* channel map control request types */
VIRTIO_SND_R_CHMAP_INFO = 0x0200,
+ /* control element request types */
+ VIRTIO_SND_R_CTL_INFO = 0x0300,
+ VIRTIO_SND_R_CTL_ENUM_ITEMS,
+ VIRTIO_SND_R_CTL_READ,
+ VIRTIO_SND_R_CTL_WRITE,
+ VIRTIO_SND_R_CTL_TLV_READ,
+ VIRTIO_SND_R_CTL_TLV_WRITE,
+ VIRTIO_SND_R_CTL_TLV_COMMAND,
+
/* jack event types */
VIRTIO_SND_EVT_JACK_CONNECTED = 0x1000,
VIRTIO_SND_EVT_JACK_DISCONNECTED,
@@ -63,6 +82,9 @@ enum {
VIRTIO_SND_EVT_PCM_PERIOD_ELAPSED = 0x1100,
VIRTIO_SND_EVT_PCM_XRUN,
+ /* control element event types */
+ VIRTIO_SND_EVT_CTL_NOTIFY = 0x1200,
+
/* common status codes */
VIRTIO_SND_S_OK = 0x8000,
VIRTIO_SND_S_BAD_MSG,
@@ -331,4 +353,136 @@ struct virtio_snd_chmap_info {
__u8 positions[VIRTIO_SND_CHMAP_MAX_SIZE];
};
+/*******************************************************************************
+ * CONTROL ELEMENTS MESSAGES
+ */
+struct virtio_snd_ctl_hdr {
+ /* VIRTIO_SND_R_CTL_XXX */
+ struct virtio_snd_hdr hdr;
+ /* 0 ... virtio_snd_config::controls - 1 */
+ __le32 control_id;
+};
+
+/* supported roles for control elements */
+enum {
+ VIRTIO_SND_CTL_ROLE_UNDEFINED = 0,
+ VIRTIO_SND_CTL_ROLE_VOLUME,
+ VIRTIO_SND_CTL_ROLE_MUTE,
+ VIRTIO_SND_CTL_ROLE_GAIN
+};
+
+/* supported value types for control elements */
+enum {
+ VIRTIO_SND_CTL_TYPE_BOOLEAN = 0,
+ VIRTIO_SND_CTL_TYPE_INTEGER,
+ VIRTIO_SND_CTL_TYPE_INTEGER64,
+ VIRTIO_SND_CTL_TYPE_ENUMERATED,
+ VIRTIO_SND_CTL_TYPE_BYTES,
+ VIRTIO_SND_CTL_TYPE_IEC958
+};
+
+/* supported access rights for control elements */
+enum {
+ VIRTIO_SND_CTL_ACCESS_READ = 0,
+ VIRTIO_SND_CTL_ACCESS_WRITE,
+ VIRTIO_SND_CTL_ACCESS_VOLATILE,
+ VIRTIO_SND_CTL_ACCESS_INACTIVE,
+ VIRTIO_SND_CTL_ACCESS_TLV_READ,
+ VIRTIO_SND_CTL_ACCESS_TLV_WRITE,
+ VIRTIO_SND_CTL_ACCESS_TLV_COMMAND
+};
+
+struct virtio_snd_ctl_info {
+ /* common header */
+ struct virtio_snd_info hdr;
+ /* element role (VIRTIO_SND_CTL_ROLE_XXX) */
+ __le32 role;
+ /* element value type (VIRTIO_SND_CTL_TYPE_XXX) */
+ __le32 type;
+ /* element access right bit map (1 << VIRTIO_SND_CTL_ACCESS_XXX) */
+ __le32 access;
+ /* # of members in the element value */
+ __le32 count;
+ /* index for an element with a non-unique name */
+ __le32 index;
+ /* name identifier string for the element */
+ __u8 name[44];
+ /* additional information about the element's value */
+ union {
+ /* VIRTIO_SND_CTL_TYPE_INTEGER */
+ struct {
+ /* minimum supported value */
+ __le32 min;
+ /* maximum supported value */
+ __le32 max;
+ /* fixed step size for value (0 = variable size) */
+ __le32 step;
+ } integer;
+ /* VIRTIO_SND_CTL_TYPE_INTEGER64 */
+ struct {
+ /* minimum supported value */
+ __le64 min;
+ /* maximum supported value */
+ __le64 max;
+ /* fixed step size for value (0 = variable size) */
+ __le64 step;
+ } integer64;
+ /* VIRTIO_SND_CTL_TYPE_ENUMERATED */
+ struct {
+ /* # of options supported for value */
+ __le32 items;
+ } enumerated;
+ } value;
+};
+
+struct virtio_snd_ctl_enum_item {
+ /* option name */
+ __u8 item[64];
+};
+
+struct virtio_snd_ctl_iec958 {
+ /* AES/IEC958 channel status bits */
+ __u8 status[24];
+ /* AES/IEC958 subcode bits */
+ __u8 subcode[147];
+ /* nothing */
+ __u8 pad;
+ /* AES/IEC958 subframe bits */
+ __u8 dig_subframe[4];
+};
+
+struct virtio_snd_ctl_value {
+ union {
+ /* VIRTIO_SND_CTL_TYPE_BOOLEAN|INTEGER value */
+ __le32 integer[128];
+ /* VIRTIO_SND_CTL_TYPE_INTEGER64 value */
+ __le64 integer64[64];
+ /* VIRTIO_SND_CTL_TYPE_ENUMERATED value (option indexes) */
+ __le32 enumerated[128];
+ /* VIRTIO_SND_CTL_TYPE_BYTES value */
+ __u8 bytes[512];
+ /* VIRTIO_SND_CTL_TYPE_IEC958 value */
+ struct virtio_snd_ctl_iec958 iec958;
+ } value;
+};
+
+/* supported event reason types */
+enum {
+ /* element's value has changed */
+ VIRTIO_SND_CTL_EVT_MASK_VALUE = 0,
+ /* element's information has changed */
+ VIRTIO_SND_CTL_EVT_MASK_INFO,
+ /* element's metadata has changed */
+ VIRTIO_SND_CTL_EVT_MASK_TLV
+};
+
+struct virtio_snd_ctl_event {
+ /* VIRTIO_SND_EVT_CTL_NOTIFY */
+ struct virtio_snd_hdr hdr;
+ /* 0 ... virtio_snd_config::controls - 1 */
+ __le16 control_id;
+ /* event reason bit map (1 << VIRTIO_SND_CTL_EVT_MASK_XXX) */
+ __le16 mask;
+};
+
#endif /* VIRTIO_SND_IF_H */
@@ -7,6 +7,7 @@ virtio_snd-objs := \
virtio_chmap.o \
virtio_ctl_msg.o \
virtio_jack.o \
+ virtio_kctl.o \
virtio_pcm.o \
virtio_pcm_msg.o \
virtio_pcm_ops.o
@@ -64,6 +64,9 @@ static void virtsnd_event_dispatch(struct virtio_snd *snd,
case VIRTIO_SND_EVT_PCM_XRUN:
virtsnd_pcm_event(snd, event);
break;
+ case VIRTIO_SND_EVT_CTL_NOTIFY:
+ virtsnd_kctl_event(snd, event);
+ break;
}
}
@@ -235,6 +238,12 @@ static int virtsnd_build_devs(struct virtio_snd *snd)
if (rc)
return rc;
+ if (virtio_has_feature(vdev, VIRTIO_SND_F_CTLS)) {
+ rc = virtsnd_kctl_parse_cfg(snd);
+ if (rc)
+ return rc;
+ }
+
if (snd->njacks) {
rc = virtsnd_jack_build_devs(snd);
if (rc)
@@ -253,6 +262,12 @@ static int virtsnd_build_devs(struct virtio_snd *snd)
return rc;
}
+ if (snd->nkctls) {
+ rc = virtsnd_kctl_build_devs(snd);
+ if (rc)
+ return rc;
+ }
+
return snd_card_register(snd->card);
}
@@ -419,10 +434,16 @@ static const struct virtio_device_id id_table[] = {
{ 0 },
};
+static unsigned int features[] = {
+ VIRTIO_SND_F_CTLS
+};
+
static struct virtio_driver virtsnd_driver = {
.driver.name = KBUILD_MODNAME,
.driver.owner = THIS_MODULE,
.id_table = id_table,
+ .feature_table = features,
+ .feature_table_size = ARRAY_SIZE(features),
.validate = virtsnd_validate,
.probe = virtsnd_probe,
.remove = virtsnd_remove,
@@ -31,6 +31,16 @@ struct virtio_snd_queue {
struct virtqueue *vqueue;
};
+/**
+ * struct virtio_kctl - VirtIO control element.
+ * @kctl: ALSA control element.
+ * @items: Items for the ENUMERATED element type.
+ */
+struct virtio_kctl {
+ struct snd_kcontrol *kctl;
+ struct virtio_snd_ctl_enum_item *items;
+};
+
/**
* struct virtio_snd - VirtIO sound card device.
* @vdev: Underlying virtio device.
@@ -45,6 +55,9 @@ struct virtio_snd_queue {
* @nsubstreams: Number of PCM substreams.
* @chmaps: VirtIO channel maps.
* @nchmaps: Number of channel maps.
+ * @kctl_infos: VirtIO control element information.
+ * @kctls: VirtIO control elements.
+ * @nkctls: Number of control elements.
*/
struct virtio_snd {
struct virtio_device *vdev;
@@ -59,6 +72,9 @@ struct virtio_snd {
u32 nsubstreams;
struct virtio_snd_chmap_info *chmaps;
u32 nchmaps;
+ struct virtio_snd_ctl_info *kctl_infos;
+ struct virtio_kctl *kctls;
+ u32 nkctls;
};
/* Message completion timeout in milliseconds (module parameter). */
@@ -108,4 +124,10 @@ int virtsnd_chmap_parse_cfg(struct virtio_snd *snd);
int virtsnd_chmap_build_devs(struct virtio_snd *snd);
+int virtsnd_kctl_parse_cfg(struct virtio_snd *snd);
+
+int virtsnd_kctl_build_devs(struct virtio_snd *snd);
+
+void virtsnd_kctl_event(struct virtio_snd *snd, struct virtio_snd_event *event);
+
#endif /* VIRTIO_SND_CARD_H */
new file mode 100644
@@ -0,0 +1,466 @@
+// 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) {
+ virtsnd_ctl_msg_unref(msg);
+ return -ENOMEM;
+ }
+
+ 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;
+ else
+ rc = virtsnd_ctl_msg_send(snd, msg, &sg, NULL, false);
+
+ break;
+ }
+
+ 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);
+}