/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2014, Neel Natu (neel@freebsd.org)
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions, and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#include "opt_bhyve_snapshot.h"

#include <sys/param.h>
#include <sys/queue.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/systm.h>

#include <machine/vmm.h>
#include <machine/vmm_snapshot.h>

#include "vpmtmr.h"

/*
 * The ACPI Power Management timer is a free-running 24- or 32-bit
 * timer with a frequency of 3.579545MHz
 *
 * This implementation will be 32-bits
 */

#define PMTMR_FREQ      3579545  /* 3.579545MHz */

struct vpmtmr {
        sbintime_t      freq_sbt;
        sbintime_t      baseuptime;
        uint32_t        baseval;
};

static MALLOC_DEFINE(M_VPMTMR, "vpmtmr", "bhyve virtual acpi timer");

struct vpmtmr *
vpmtmr_init(struct vm *vm)
{
        struct vpmtmr *vpmtmr;
        struct bintime bt;

        vpmtmr = malloc(sizeof(struct vpmtmr), M_VPMTMR, M_WAITOK | M_ZERO);
        vpmtmr->baseuptime = sbinuptime();
        vpmtmr->baseval = 0;

        FREQ2BT(PMTMR_FREQ, &bt);
        vpmtmr->freq_sbt = bttosbt(bt);

        return (vpmtmr);
}

void
vpmtmr_cleanup(struct vpmtmr *vpmtmr)
{

        free(vpmtmr, M_VPMTMR);
}

int
vpmtmr_handler(struct vm *vm, bool in, int port, int bytes, uint32_t *val)
{
        struct vpmtmr *vpmtmr;
        sbintime_t now, delta;

        if (!in || bytes != 4)
                return (-1);

        vpmtmr = vm_pmtmr(vm);

        /*
         * No locking needed because 'baseuptime' and 'baseval' are
         * written only during initialization.
         */
        now = sbinuptime();
        delta = now - vpmtmr->baseuptime;
        KASSERT(delta >= 0, ("vpmtmr_handler: uptime went backwards: "
            "%#lx to %#lx", vpmtmr->baseuptime, now));
        *val = vpmtmr->baseval + delta / vpmtmr->freq_sbt;

        return (0);
}

#ifdef BHYVE_SNAPSHOT
int
vpmtmr_snapshot(struct vpmtmr *vpmtmr, struct vm_snapshot_meta *meta)
{
        int ret;

        SNAPSHOT_VAR_OR_LEAVE(vpmtmr->baseval, meta, ret, done);

done:
        return (ret);
}
#endif