linux-brain/sound/xen/xen_snd_front.h
Oleksandr Andrushchenko 1cee559351 ALSA: xen-front: Implement ALSA virtual sound driver
Implement essential initialization of the sound driver:
  - introduce required data structures
  - handle driver registration
  - handle sound card registration
  - register sound driver on backend connection
  - remove sound driver on backend disconnect

Initialize virtual sound card with streams according to the
Xen store configuration.

Implement ALSA driver operations including:
  - manage frontend/backend shared buffers
  - manage Xen bus event channel states

Implement requests from front to back for ALSA
PCM operations.
  - report ALSA period elapsed event: handle XENSND_EVT_CUR_POS
    notifications from the backend when stream position advances
    during playback/capture. The event carries a value of how
    many octets were played/captured at the time of the event.
  - implement explicit stream parameter negotiation between
    backend and frontend: handle XENSND_OP_HW_PARAM_QUERY request
    to read/update configuration space for the parameter given:
    request passes desired parameter interval and the response to
    this request returns min/max interval for the parameter to be used.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2018-05-16 12:59:57 +02:00

55 lines
1.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 OR MIT */
/*
* Xen para-virtual sound device
*
* Copyright (C) 2016-2018 EPAM Systems Inc.
*
* Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
*/
#ifndef __XEN_SND_FRONT_H
#define __XEN_SND_FRONT_H
#include "xen_snd_front_cfg.h"
struct xen_snd_front_card_info;
struct xen_snd_front_evtchnl;
struct xen_snd_front_evtchnl_pair;
struct xen_snd_front_shbuf;
struct xensnd_query_hw_param;
struct xen_snd_front_info {
struct xenbus_device *xb_dev;
struct xen_snd_front_card_info *card_info;
int num_evt_pairs;
struct xen_snd_front_evtchnl_pair *evt_pairs;
struct xen_front_cfg_card cfg;
};
int xen_snd_front_stream_query_hw_param(struct xen_snd_front_evtchnl *evtchnl,
struct xensnd_query_hw_param *hw_param_req,
struct xensnd_query_hw_param *hw_param_resp);
int xen_snd_front_stream_prepare(struct xen_snd_front_evtchnl *evtchnl,
struct xen_snd_front_shbuf *sh_buf,
u8 format, unsigned int channels,
unsigned int rate, u32 buffer_sz,
u32 period_sz);
int xen_snd_front_stream_close(struct xen_snd_front_evtchnl *evtchnl);
int xen_snd_front_stream_write(struct xen_snd_front_evtchnl *evtchnl,
unsigned long pos, unsigned long count);
int xen_snd_front_stream_read(struct xen_snd_front_evtchnl *evtchnl,
unsigned long pos, unsigned long count);
int xen_snd_front_stream_trigger(struct xen_snd_front_evtchnl *evtchnl,
int type);
#endif /* __XEN_SND_FRONT_H */