/*-
 * Copyright (c) 2015,2016 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, 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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>
__FBSDID("$FreeBSD: head/sys/dev/hyperv/vmbus/hv_et.c 298449 2016-04-22 05:15:59Z sephe $");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/smp.h>
#include <sys/time.h>
#include <sys/timeet.h>

#include "hv_vmbus_priv.h"

#define HV_TIMER_FREQUENCY		(10 * 1000 * 1000LL) /* 100ns period */
#define HV_MAX_DELTA_TICKS		0xffffffffLL
#define HV_MIN_DELTA_TICKS		1LL

static struct eventtimer *et;

static inline uint64_t
sbintime2tick(sbintime_t time)
{
	struct timespec val;

	val = sbttots(time);
	return val.tv_sec * HV_TIMER_FREQUENCY + val.tv_nsec / 100;
}

static int
hv_et_start(struct eventtimer *et, sbintime_t firsttime, sbintime_t periodtime)
{
	union hv_timer_config timer_cfg;
	uint64_t current;

	timer_cfg.as_uint64 = 0;
	timer_cfg.auto_enable = 1;
	timer_cfg.sintx = HV_VMBUS_TIMER_SINT;

	current = rdmsr(HV_X64_MSR_TIME_REF_COUNT);
	current += sbintime2tick(firsttime);

	wrmsr(HV_X64_MSR_STIMER0_CONFIG, timer_cfg.as_uint64);
	wrmsr(HV_X64_MSR_STIMER0_COUNT, current);

	return (0);
}

static int
hv_et_stop(struct eventtimer *et)
{
	wrmsr(HV_X64_MSR_STIMER0_CONFIG, 0);
	wrmsr(HV_X64_MSR_STIMER0_COUNT, 0);

	return (0);
}

void
hv_et_intr(struct trapframe *frame)
{
	struct trapframe *oldframe;
	struct thread *td;

	if (et->et_active) {
		td = curthread;
		td->td_intr_nesting_level++;
		oldframe = td->td_intr_frame;
		td->td_intr_frame = frame;
		et->et_event_cb(et, et->et_arg);
		td->td_intr_frame = oldframe;
		td->td_intr_nesting_level--;
	}
}

static void
hv_et_identify (driver_t *driver, device_t parent)
{
	if (device_find_child(parent, "hv_et", -1) != NULL)
		return;

	device_add_child(parent, "hv_et", -1);
}

static int
hv_et_probe(device_t dev)
{
	device_set_desc(dev, "Hyper-V event timer");

	return (BUS_PROBE_NOWILDCARD);
}

static int
hv_et_attach(device_t dev)
{
	/* XXX: need allocate SINT and remove global et */
	et = device_get_softc(dev);

	et->et_name = "Hyper-V";
	et->et_flags = ET_FLAGS_ONESHOT | ET_FLAGS_PERCPU;
	et->et_quality = 1000;
	et->et_frequency = HV_TIMER_FREQUENCY;
	et->et_min_period = HV_MIN_DELTA_TICKS * ((1LL << 32) / HV_TIMER_FREQUENCY);
	et->et_max_period = HV_MAX_DELTA_TICKS * ((1LL << 32) / HV_TIMER_FREQUENCY);
	et->et_start = hv_et_start;
	et->et_stop = hv_et_stop;
	et->et_priv = dev;

	return (et_register(et));
}

static int
hv_et_detach(device_t dev)
{
	return (et_deregister(et));
}

static device_method_t hv_et_methods[] = {
	DEVMETHOD(device_identify,      hv_et_identify),
	DEVMETHOD(device_probe,         hv_et_probe),
	DEVMETHOD(device_attach,        hv_et_attach),
	DEVMETHOD(device_detach,        hv_et_detach),

	DEVMETHOD_END
};

static driver_t hv_et_driver = {
	"hv_et",
	hv_et_methods,
	sizeof(struct eventtimer)
};

static devclass_t hv_et_devclass;
DRIVER_MODULE(hv_et, vmbus, hv_et_driver, hv_et_devclass, NULL, 0);
MODULE_VERSION(hv_et, 1);