/*      $NetBSD: hvtimesync.c,v 1.3 2022/11/02 18:18:44 andvar Exp $    */

/*-
 * Copyright (c) 2014,2016-2017 Microsoft Corp.
 * 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>
#ifdef __KERNEL_RCSID
__KERNEL_RCSID(0, "$NetBSD: hvtimesync.c,v 1.3 2022/11/02 18:18:44 andvar Exp $");
#endif
#ifdef __FBSDID
__FBSDID("$FreeBSD: head/sys/dev/hyperv/utilities/vmbus_timesync.c 322488 2017-08-14 06:00:50Z sephe $");
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/module.h>
#include <sys/pmf.h>
#include <sys/sysctl.h>
#include <sys/timetc.h>

#include <dev/hyperv/vmbusvar.h>
#include <dev/hyperv/vmbusicreg.h>
#include <dev/hyperv/vmbusicvar.h>

#define VMBUS_TIMESYNC_FWVER_MAJOR      3
#define VMBUS_TIMESYNC_FWVER            \
            VMBUS_IC_VERSION(VMBUS_TIMESYNC_FWVER_MAJOR, 0)

#define VMBUS_TIMESYNC_MSGVER_MAJOR     4
#define VMBUS_TIMESYNC_MSGVER           \
            VMBUS_IC_VERSION(VMBUS_TIMESYNC_MSGVER_MAJOR, 0)

#define VMBUS_TIMESYNC_MSGVER4(sc)      \
            VMBUS_ICVER_LE(VMBUS_IC_VERSION(4, 0), (sc)->sc_vmbusic.sc_msgver)

#define VMBUS_TIMESYNC_DORTT(sc)        \
            (VMBUS_TIMESYNC_MSGVER4((sc)) && (hyperv_tc64 != NULL))

static int      hvtimesync_match(device_t, cfdata_t, void *);
static void     hvtimesync_attach(device_t, device_t, void *);
static int      hvtimesync_detach(device_t, int);

static void     hvtimesync_channel_cb(void *);
static int      hvtimesync_sysctl_setup(device_t);

struct hvtimesync_softc {
        struct vmbusic_softc    sc_vmbusic;
};

CFATTACH_DECL_NEW(hvtimesync, sizeof(struct hvtimesync_softc),
    hvtimesync_match, hvtimesync_attach, hvtimesync_detach, NULL);

static int hvtimesync_ignore_sync;
static int hvtimesync_sample_verbose;
static int hvtimesync_sample_thresh = -1;

static int
hvtimesync_match(device_t parent, cfdata_t cf, void *aux)
{
        struct vmbus_attach_args *aa = aux;

        return vmbusic_probe(aa, &hyperv_guid_timesync);
}

static void
hvtimesync_attach(device_t parent, device_t self, void *aux)
{
        struct vmbus_attach_args *aa = aux;
        int error;

        aprint_naive("\n");
        aprint_normal(": Hyper-V Time Synchronization Service\n");

        error = vmbusic_attach(self, aa, hvtimesync_channel_cb);
        if (error)
                return;

        (void) pmf_device_register(self, NULL, NULL);

        (void) hvtimesync_sysctl_setup(self);
}

static int
hvtimesync_detach(device_t self, int flags)
{
        int error;

        error = vmbusic_detach(self, flags);
        if (error)
                return error;

        pmf_device_deregister(self);

        return 0;
}

static void
do_timesync(struct hvtimesync_softc *sc, uint64_t hvtime, uint64_t sent_tc,
    uint8_t tsflags)
{
        struct vmbusic_softc *vsc = &sc->sc_vmbusic;
        struct timespec vm_ts, hv_ts;
        uint64_t hv_ns, vm_ns, rtt = 0;
        int64_t diff;

        if (VMBUS_TIMESYNC_DORTT(sc))
                rtt = hyperv_tc64() - sent_tc;

        hv_ns = (hvtime - VMBUS_ICMSG_TS_BASE + rtt) * HYPERV_TIMER_NS_FACTOR;
        nanotime(&vm_ts);
        vm_ns = (vm_ts.tv_sec * NANOSECOND) + vm_ts.tv_nsec;

        if ((tsflags & VMBUS_ICMSG_TS_FLAG_SYNC) && !hvtimesync_ignore_sync) {
#if 0
                device_printf(vsc->sc_dev,
                    "apply sync request, hv: %ju, vm: %ju\n",
                    (uintmax_t)hv_ns, (uintmax_t)vm_ns);
#endif
                hv_ts.tv_sec = hv_ns / NANOSECOND;
                hv_ts.tv_nsec = hv_ns % NANOSECOND;
                tc_setclock(&hv_ts);
                /* Done! */
                return;
        }

        if ((tsflags & VMBUS_ICMSG_TS_FLAG_SAMPLE) &&
            hvtimesync_sample_thresh >= 0) {
                if (hvtimesync_sample_verbose) {
                        device_printf(vsc->sc_dev,
                            "sample request, hv: %ju, vm: %ju\n",
                            (uintmax_t)hv_ns, (uintmax_t)vm_ns);
                }

                if (hv_ns > vm_ns)
                        diff = hv_ns - vm_ns;
                else
                        diff = vm_ns - hv_ns;
                /* nanosec -> millisec */
                diff /= 1000000;

                if (diff > hvtimesync_sample_thresh) {
                        device_printf(vsc->sc_dev,
                            "apply sample request, hv: %ju, vm: %ju\n",
                            (uintmax_t)hv_ns, (uintmax_t)vm_ns);
                        hv_ts.tv_sec = hv_ns / NANOSECOND;
                        hv_ts.tv_nsec = hv_ns % NANOSECOND;
                        tc_setclock(&hv_ts);
                }
                /* Done */
                return;
        }
}

static void
hvtimesync_channel_cb(void *arg)
{
        struct hvtimesync_softc *sc = arg;
        struct vmbusic_softc *vsc = &sc->sc_vmbusic;
        struct vmbus_channel *ch = vsc->sc_chan;
        struct vmbus_icmsg_hdr *hdr;
        uint64_t rid;
        uint32_t rlen;
        int error;

        error = vmbus_channel_recv(ch, vsc->sc_buf, vsc->sc_buflen,
            &rlen, &rid, 0);
        if (error || rlen == 0) {
                if (error != EAGAIN) {
                        DPRINTF("%s: timesync error=%d len=%u\n",
                            device_xname(vsc->sc_dev), error, rlen);
                }
                return;
        }
        if (rlen < sizeof(*hdr)) {
                DPRINTF("%s: hvtimesync short read len=%u\n",
                    device_xname(vsc->sc_dev), rlen);
                return;
        }

        hdr = (struct vmbus_icmsg_hdr *)vsc->sc_buf;
        switch (hdr->ic_type) {
        case VMBUS_ICMSG_TYPE_NEGOTIATE:
                error = vmbusic_negotiate(vsc, hdr, &rlen, VMBUS_TIMESYNC_FWVER,
                    VMBUS_TIMESYNC_MSGVER);
                if (error)
                        return;
                if (VMBUS_TIMESYNC_DORTT(sc)) {
                        DPRINTF("%s: RTT\n", device_xname(vsc->sc_dev));
                }
                break;

        case VMBUS_ICMSG_TYPE_TIMESYNC:
                if (VMBUS_TIMESYNC_MSGVER4(sc)) {
                        struct vmbus_icmsg_timesync4 *msg4;

                        if (rlen < sizeof(*msg4)) {
                                DPRINTF("%s: invalid timesync4 len=%u\n",
                                    device_xname(vsc->sc_dev), rlen);
                                return;
                        }

                        msg4 = (struct vmbus_icmsg_timesync4 *)hdr;
                        do_timesync(sc, msg4->ic_hvtime, msg4->ic_sent_tc,
                            msg4->ic_tsflags);
                } else {
                        struct vmbus_icmsg_timesync *msg;

                        if (rlen < sizeof(*msg)) {
                                DPRINTF("%s: invalid timesync len=%u\n",
                                    device_xname(vsc->sc_dev), rlen);
                                return;
                        }

                        msg = (struct vmbus_icmsg_timesync *)hdr;
                        do_timesync(sc, msg->ic_hvtime, 0, msg->ic_tsflags);
                }
                break;

        default:
                device_printf(vsc->sc_dev,
                    "unhandled _timesync message type %u\n", hdr->ic_type);
                return;
        }

        (void) vmbusic_sendresp(vsc, ch, vsc->sc_buf, rlen, rid);
}

static int
hvtimesync_sysctl_setup(device_t self)
{
        struct hvtimesync_softc *sc = device_private(self);
        struct vmbusic_softc *vsc = &sc->sc_vmbusic;
        const struct sysctlnode *node;
        int error;

        error = sysctl_createv(NULL, 0, NULL, &node,
            CTLFLAG_PERMANENT, CTLTYPE_NODE, "machdep", NULL,
            NULL, 0, NULL, 0, CTL_MACHDEP, CTL_EOL);
        if (error)
                return error;
        error = sysctl_createv(NULL, 0, &node, &node,
            CTLFLAG_PERMANENT, CTLTYPE_NODE, "hyperv", NULL,
            NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL);
        if (error)
                return error;

        error = sysctl_createv(&vsc->sc_log, 0, &node, &node,
            0, CTLTYPE_NODE, "timesync", NULL,
            NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL);
        if (error)
                return error;

        error = sysctl_createv(&vsc->sc_log, 0, &node, NULL,
            CTLFLAG_READWRITE,
            CTLTYPE_INT, "ignore_sync", NULL,
            NULL, 0, &hvtimesync_ignore_sync, 0,
            CTL_CREATE, CTL_EOL);
        if (error)
                return error;
        error = sysctl_createv(&vsc->sc_log, 0, &node, NULL,
            CTLFLAG_READWRITE,
            CTLTYPE_INT, "sample_verbose", NULL,
            NULL, 0, &hvtimesync_sample_verbose, 0,
            CTL_CREATE, CTL_EOL);
        if (error)
                return error;
        error = sysctl_createv(&vsc->sc_log, 0, &node, NULL,
            CTLFLAG_READWRITE,
            CTLTYPE_INT, "sample_thresh", NULL,
            NULL, 0, &hvtimesync_sample_thresh, 0,
            CTL_CREATE, CTL_EOL);
        if (error)
                return error;

        return 0;
}

MODULE(MODULE_CLASS_DRIVER, hvtimesync, "vmbus");

#ifdef _MODULE
#include "ioconf.c"
#endif

static int
hvtimesync_modcmd(modcmd_t cmd, void *aux)
{
        int error = 0;

        switch (cmd) {
        case MODULE_CMD_INIT:
#ifdef _MODULE
                error = config_init_component(cfdriver_ioconf_hvtimesync,
                    cfattach_ioconf_hvtimesync, cfdata_ioconf_hvtimesync);
#endif
                break;

        case MODULE_CMD_FINI:
#ifdef _MODULE
                error = config_fini_component(cfdriver_ioconf_hvtimesync,
                    cfattach_ioconf_hvtimesync, cfdata_ioconf_hvtimesync);
#endif
                break;

        case MODULE_CMD_AUTOUNLOAD:
                error = EBUSY;
                break;

        default:
                error = ENOTTY;
                break;
        }

        return error;
}