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/*
* VIRTIO Sound Device conforming to
*
* "Virtual I/O Device (VIRTIO) Version 1.2
* Committee Specification Draft 01
* 09 May 2022"
*
* Copyright (c) 2023 Emmanouil Pitsidianakis <manos.pitsidianakis@linaro.org>
* Copyright (C) 2019 OpenSynergy GmbH
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* (at your option) any later version. See the COPYING file in the
* top-level directory.
*/
#ifndef QEMU_VIRTIO_SOUND_H
#define QEMU_VIRTIO_SOUND_H
#include "hw/virtio/virtio.h"
#include "audio/audio.h"
#include "standard-headers/linux/virtio_ids.h"
#include "standard-headers/linux/virtio_snd.h"
#define TYPE_VIRTIO_SND "virtio-sound-device"
#define VIRTIO_SND(obj) \
OBJECT_CHECK(VirtIOSound, (obj), TYPE_VIRTIO_SND)
/* CONFIGURATION SPACE */
typedef struct virtio_snd_config virtio_snd_config;
/* COMMON DEFINITIONS */
/* common header for request/response*/
typedef struct virtio_snd_hdr virtio_snd_hdr;
/* event notification */
typedef struct virtio_snd_event virtio_snd_event;
/* common control request to query an item information */
typedef struct virtio_snd_query_info virtio_snd_query_info;
/* JACK CONTROL MESSAGES */
typedef struct virtio_snd_jack_hdr virtio_snd_jack_hdr;
/* jack information structure */
typedef struct virtio_snd_jack_info virtio_snd_jack_info;
/* jack remapping control request */
typedef struct virtio_snd_jack_remap virtio_snd_jack_remap;
/*
* PCM CONTROL MESSAGES
*/
typedef struct virtio_snd_pcm_hdr virtio_snd_pcm_hdr;
/* PCM stream info structure */
typedef struct virtio_snd_pcm_info virtio_snd_pcm_info;
/* set PCM stream params */
typedef struct virtio_snd_pcm_set_params virtio_snd_pcm_set_params;
/* I/O request header */
typedef struct virtio_snd_pcm_xfer virtio_snd_pcm_xfer;
/* I/O request status */
typedef struct virtio_snd_pcm_status virtio_snd_pcm_status;
/* device structs */
typedef struct VirtIOSound VirtIOSound;
typedef struct VirtIOSoundPCMStream VirtIOSoundPCMStream;
typedef struct virtio_snd_ctrl_command virtio_snd_ctrl_command;
typedef struct VirtIOSoundPCM VirtIOSoundPCM;
typedef struct VirtIOSoundPCMBuffer VirtIOSoundPCMBuffer;
/*
* The VirtIO sound spec reuses layouts and values from the High Definition
* Audio spec (virtio/v1.2: 5.14 Sound Device). This struct handles each I/O
* message's buffer (virtio/v1.2: 5.14.6.8 PCM I/O Messages).
*
* In the case of TX (i.e. playback) buffers, we defer reading the raw PCM data
* from the virtqueue until QEMU's sound backsystem calls the output callback.
* This is tracked by the `bool populated;` field, which is set to true when
* data has been read into our own buffer for consumption.
*
* VirtIOSoundPCMBuffer has a dynamic size since it includes the raw PCM data
* in its allocation. It must be initialized and destroyed as follows:
*
* size_t size = [[derived from owned VQ element descriptor sizes]];
* buffer = g_malloc0(sizeof(VirtIOSoundPCMBuffer) + size);
* buffer->elem = [[owned VQ element]];
*
* [..]
*
* g_free(buffer->elem);
* g_free(buffer);
*/
struct VirtIOSoundPCMBuffer {
QSIMPLEQ_ENTRY(VirtIOSoundPCMBuffer) entry;
VirtQueueElement *elem;
VirtQueue *vq;
size_t size;
/*
* In TX / Plaback, `offset` represents the first unused position inside
* `data`. If `offset == size` then there are no unused data left.
*/
uint64_t offset;
/* Used for the TX queue for lazy I/O copy from `elem` */
bool populated;
/*
* VirtIOSoundPCMBuffer is an unsized type because it ends with an array of
* bytes. The size of `data` is determined from the I/O message's read-only
* or write-only size when allocating VirtIOSoundPCMBuffer.
*/
uint8_t data[];
};
struct VirtIOSoundPCM {
VirtIOSound *snd;
/*
* PCM parameters are a separate field instead of a VirtIOSoundPCMStream
* field, because the operation of PCM control requests is first
* VIRTIO_SND_R_PCM_SET_PARAMS and then VIRTIO_SND_R_PCM_PREPARE; this
* means that some times we get parameters without having an allocated
* stream yet.
*/
virtio_snd_pcm_set_params *pcm_params;
VirtIOSoundPCMStream **streams;
};
struct VirtIOSoundPCMStream {
VirtIOSoundPCM *pcm;
virtio_snd_pcm_info info;
virtio_snd_pcm_set_params params;
uint32_t id;
/* channel position values (VIRTIO_SND_CHMAP_XXX) */
uint8_t positions[VIRTIO_SND_CHMAP_MAX_SIZE];
VirtIOSound *s;
bool flushing;
audsettings as;
union {
SWVoiceIn *in;
SWVoiceOut *out;
} voice;
QemuMutex queue_mutex;
bool active;
QSIMPLEQ_HEAD(, VirtIOSoundPCMBuffer) queue;
};
/*
* PCM stream state machine.
* -------------------------
*
* 5.14.6.6.1 PCM Command Lifecycle
* ================================
*
* A PCM stream has the following command lifecycle:
* - `SET PARAMETERS`
* The driver negotiates the stream parameters (format, transport, etc) with
* the device.
* Possible valid transitions: `SET PARAMETERS`, `PREPARE`.
* - `PREPARE`
* The device prepares the stream (allocates resources, etc).
* Possible valid transitions: `SET PARAMETERS`, `PREPARE`, `START`,
* `RELEASE`. Output only: the driver transfers data for pre-buffing.
* - `START`
* The device starts the stream (unmute, putting into running state, etc).
* Possible valid transitions: `STOP`.
* The driver transfers data to/from the stream.
* - `STOP`
* The device stops the stream (mute, putting into non-running state, etc).
* Possible valid transitions: `START`, `RELEASE`.
* - `RELEASE`
* The device releases the stream (frees resources, etc).
* Possible valid transitions: `SET PARAMETERS`, `PREPARE`.
*
* +---------------+ +---------+ +---------+ +-------+ +-------+
* | SetParameters | | Prepare | | Release | | Start | | Stop |
* +---------------+ +---------+ +---------+ +-------+ +-------+
* |- | | | |
* || | | | |
* |< | | | |
* |------------->| | | |
* |<-------------| | | |
* | |- | | |
* | || | | |
* | |< | | |
* | |--------------------->| |
* | |---------->| | |
* | | | |-------->|
* | | | |<--------|
* | | |<-------------------|
* |<-------------------------| | |
* | |<----------| | |
*
* CTRL in the VirtIOSound device
* ==============================
*
* The control messages that affect the state of a stream arrive in the
* `virtio_snd_handle_ctrl()` queue callback and are of type `struct
* virtio_snd_ctrl_command`. They are stored in a queue field in the device
* type, `VirtIOSound`. This allows deferring the CTRL request completion if
* it's not immediately possible due to locking/state reasons.
*
* The CTRL message is finally handled in `process_cmd()`.
*/
struct VirtIOSound {
VirtIODevice parent_obj;
VirtQueue *queues[VIRTIO_SND_VQ_MAX];
uint64_t features;
VirtIOSoundPCM *pcm;
QEMUSoundCard card;
VMChangeStateEntry *vmstate;
virtio_snd_config snd_conf;
QemuMutex cmdq_mutex;
QTAILQ_HEAD(, virtio_snd_ctrl_command) cmdq;
bool processing_cmdq;
/*
* Convenience queue to keep track of invalid tx/rx queue messages inside
* the tx/rx callbacks.
*
* In the callbacks as a first step we are emptying the virtqueue to handle
* each message and we cannot add an invalid message back to the queue: we
* would re-process it in subsequent loop iterations.
*
* Instead, we add them to this queue and after finishing examining every
* virtqueue element, we inform the guest for each invalid message.
*
* This queue must be empty at all times except for inside the tx/rx
* callbacks.
*/
QSIMPLEQ_HEAD(, VirtIOSoundPCMBuffer) invalid;
};
struct virtio_snd_ctrl_command {
VirtQueueElement *elem;
VirtQueue *vq;
virtio_snd_hdr ctrl;
virtio_snd_hdr resp;
size_t payload_size;
QTAILQ_ENTRY(virtio_snd_ctrl_command) next;
};
#endif
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