ALSA: virtio: add support for audio controls

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>

ALSA: virtio: introduce PCM channel map support

Enumerate all available PCM channel maps and create ALSA controls.

Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com>
Link: https://lore.kernel.org/r/20210302164709.3142702-9-anton.yakovlev@opensynergy.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: virtio: introduce jack support

Enumerate all available jacks and create ALSA controls.

At the moment jacks have a simple implementation and can only be used
to receive notifications about a plugged in/out device.

Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com>
Link: https://lore.kernel.org/r/20210302164709.3142702-8-anton.yakovlev@opensynergy.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: virtio: handling control and I/O messages for the PCM device

The driver implements a message-based transport for I/O substream
operations. Before the start of the substream, the hardware buffer is
sliced into I/O messages, the number of which is equal to the current
number of periods. The size of each message is equal to the current
size of one period.

I/O messages are organized in an ordered queue. The completion of the
I/O message indicates an elapsed period (the only exception is the end
of the stream for the capture substream). Upon completion, the message
is automatically re-added to the end of the queue.

Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com>
Link: https://lore.kernel.org/r/20210302164709.3142702-6-anton.yakovlev@opensynergy.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: virtio: build PCM devices and substream hardware descriptors

Like the HDA specification, the virtio sound device specification links
PCM substreams, jacks and PCM channel maps into functional groups. For
each discovered group, a PCM device is created, the number of which
coincides with the group number.

Introduce the module parameters for setting the hardware buffer
parameters:
pcm_buffer_ms [=160]
pcm_periods_min [=2]
pcm_periods_max [=16]
pcm_period_ms_min [=10]
pcm_period_ms_max [=80]

Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com>
Link: https://lore.kernel.org/r/20210302164709.3142702-5-anton.yakovlev@opensynergy.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: virtio: handling control messages

The control queue can be used by different parts of the driver to send
commands to the device. Control messages can be either synchronous or
asynchronous. The lifetime of a message is controlled by a reference
count.

Introduce a module parameter to set the message completion timeout:
msg_timeout_ms [=1000]

Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com>
Link: https://lore.kernel.org/r/20210302164709.3142702-4-anton.yakovlev@opensynergy.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: virtio: add virtio sound driver

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>