As defined in the specification, the `controls` field in the configuration
space is only valid/present if VIRTIO_SND_F_CTLS is negotiated.
From https://docs.oasis-open.org/virtio/virtio/v1.3/virtio-v1.3.html:
5.14.4 Device Configuration Layout
...
controls
(driver-read-only) indicates a total number of all available control
elements if VIRTIO_SND_F_CTLS has been negotiated.
Let's use the same style used in virtio_blk.h to clarify this and to avoid
confusion as happened in QEMU (see link).
Link: https://gitlab.com/qemu-project/qemu/-/issues/2805
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20250213161825.139952-1-sgarzare@redhat.com
Implementation of support for audio controls in accordance with the
extension of the virtio sound device specification [1] planned for
virtio-v1.3-cs01.
The device can announce the VIRTIO_SND_F_CTLS feature. If the feature is
negotiated, then an additional field appears in the configuration space:
struct virtio_snd_config {
...
/* number of available control elements */
__le32 controls;
};
The driver can send the following requests to manage audio controls:
enum {
...
/* 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,
...
};
And the device can send the following audio control event notification:
enum {
...
/* control element event types */
VIRTIO_SND_EVT_CTL_NOTIFY = 0x1200,
...
};
See additional details in [1].
[1] https://lists.oasis-open.org/archives/virtio-comment/202104/msg00013.html
Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com>
Signed-off-by: Aiswarya Cyriac <aiswarya.cyriac@opensynergy.com>
Link: https://lore.kernel.org/r/20240115133654.576068-2-aiswarya.cyriac@opensynergy.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Introduce skeleton of the virtio sound driver. The driver implements
the virtio sound device specification, which has become part of the
virtio standard.
Initial initialization of the device, virtqueues and creation of an
empty ALSA sound device.
Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com>
Link: https://lore.kernel.org/r/20210302164709.3142702-3-anton.yakovlev@opensynergy.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Stefano Garzarella
Anton Yakovlev