/* 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_EVTCHNL_H
#define __XEN_SND_FRONT_EVTCHNL_H

#include <xen/interface/io/sndif.h>

struct xen_snd_front_info;

/* Timeout in ms to wait for backend to respond. */
#define VSND_WAIT_BACK_MS       3000

enum xen_snd_front_evtchnl_state {
        EVTCHNL_STATE_DISCONNECTED,
        EVTCHNL_STATE_CONNECTED,
};

enum xen_snd_front_evtchnl_type {
        EVTCHNL_TYPE_REQ,
        EVTCHNL_TYPE_EVT,
};

struct xen_snd_front_evtchnl {
        struct xen_snd_front_info *front_info;
        int gref;
        int port;
        int irq;
        int index;
        /* State of the event channel. */
        enum xen_snd_front_evtchnl_state state;
        enum xen_snd_front_evtchnl_type type;
        /* Either response id or incoming event id. */
        u16 evt_id;
        /* Next request id or next expected event id. */
        u16 evt_next_id;
        /* Shared ring access lock. */
        struct mutex ring_io_lock;
        union {
                struct {
                        struct xen_sndif_front_ring ring;
                        struct completion completion;
                        /* Serializer for backend IO: request/response. */
                        struct mutex req_io_lock;

                        /* Latest response status. */
                        int resp_status;
                        union {
                                struct xensnd_query_hw_param hw_param;
                        } resp;
                } req;
                struct {
                        struct xensnd_event_page *page;
                        /* This is needed to handle XENSND_EVT_CUR_POS event. */
                        struct snd_pcm_substream *substream;
                } evt;
        } u;
};

struct xen_snd_front_evtchnl_pair {
        struct xen_snd_front_evtchnl req;
        struct xen_snd_front_evtchnl evt;
};

int xen_snd_front_evtchnl_create_all(struct xen_snd_front_info *front_info,
                                     int num_streams);

void xen_snd_front_evtchnl_free_all(struct xen_snd_front_info *front_info);

int xen_snd_front_evtchnl_publish_all(struct xen_snd_front_info *front_info);

void xen_snd_front_evtchnl_flush(struct xen_snd_front_evtchnl *evtchnl);

void xen_snd_front_evtchnl_pair_set_connected(struct xen_snd_front_evtchnl_pair *evt_pair,
                                              bool is_connected);

void xen_snd_front_evtchnl_pair_clear(struct xen_snd_front_evtchnl_pair *evt_pair);

#endif /* __XEN_SND_FRONT_EVTCHNL_H */