freebsd-skq/sys/dev/hyperv/vmbus/vmbus_et.c

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/*-
* 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("$FreeBSD$");
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <sys/smp.h>
#include <sys/systm.h>
#include <sys/timeet.h>
#include <dev/hyperv/vmbus/hyperv_reg.h>
#include <dev/hyperv/vmbus/hyperv_var.h>
#include <dev/hyperv/vmbus/vmbus_var.h>
#define VMBUS_ET_NAME "hvet"
#define MSR_HV_STIMER0_CFG_SINT \
((((uint64_t)VMBUS_SINT_TIMER) << MSR_HV_STIMER_CFG_SINT_SHIFT) & \
MSR_HV_STIMER_CFG_SINT_MASK)
/*
* Two additionally required features:
* - SynIC is needed for interrupt generation.
* - Time reference counter is needed to set ABS reference count to
* STIMER0_COUNT.
*/
#define CPUID_HV_ET_MASK (CPUID_HV_MSR_TIME_REFCNT | \
CPUID_HV_MSR_SYNIC | \
CPUID_HV_MSR_SYNTIMER)
static void vmbus_et_identify(driver_t *, device_t);
static int vmbus_et_probe(device_t);
static int vmbus_et_attach(device_t);
static int vmbus_et_detach(device_t);
static int vmbus_et_start(struct eventtimer *, sbintime_t,
sbintime_t);
static struct eventtimer vmbus_et;
static device_method_t vmbus_et_methods[] = {
DEVMETHOD(device_identify, vmbus_et_identify),
DEVMETHOD(device_probe, vmbus_et_probe),
DEVMETHOD(device_attach, vmbus_et_attach),
DEVMETHOD(device_detach, vmbus_et_detach),
DEVMETHOD_END
};
static driver_t vmbus_et_driver = {
VMBUS_ET_NAME,
vmbus_et_methods,
0
};
static devclass_t vmbus_et_devclass;
DRIVER_MODULE(hv_et, vmbus, vmbus_et_driver, vmbus_et_devclass, NULL, NULL);
MODULE_VERSION(hv_et, 1);
static __inline uint64_t
hyperv_sbintime2count(sbintime_t time)
{
struct timespec val;
val = sbttots(time);
return (val.tv_sec * HYPERV_TIMER_FREQ) +
(val.tv_nsec / HYPERV_TIMER_NS_FACTOR);
}
static int
vmbus_et_start(struct eventtimer *et __unused, sbintime_t first,
sbintime_t period __unused)
{
uint64_t current;
current = rdmsr(MSR_HV_TIME_REF_COUNT);
current += hyperv_sbintime2count(first);
wrmsr(MSR_HV_STIMER0_COUNT, current);
return (0);
}
void
vmbus_et_intr(struct trapframe *frame)
{
struct trapframe *oldframe;
struct thread *td;
if (vmbus_et.et_active) {
td = curthread;
td->td_intr_nesting_level++;
oldframe = td->td_intr_frame;
td->td_intr_frame = frame;
vmbus_et.et_event_cb(&vmbus_et, vmbus_et.et_arg);
td->td_intr_frame = oldframe;
td->td_intr_nesting_level--;
}
}
static void
vmbus_et_identify(driver_t *driver, device_t parent)
{
if (device_get_unit(parent) != 0 ||
device_find_child(parent, VMBUS_ET_NAME, -1) != NULL ||
(hyperv_features & CPUID_HV_ET_MASK) != CPUID_HV_ET_MASK)
return;
device_add_child(parent, VMBUS_ET_NAME, -1);
}
static int
vmbus_et_probe(device_t dev)
{
if (resource_disabled(VMBUS_ET_NAME, 0))
return (ENXIO);
device_set_desc(dev, "Hyper-V event timer");
return (BUS_PROBE_NOWILDCARD);
}
static void
vmbus_et_config(void *arg __unused)
{
/*
* Make sure that STIMER0 is really disabled before writing
* to STIMER0_CONFIG.
*
* "Writing to the configuration register of a timer that
* is already enabled may result in undefined behaviour."
*/
for (;;) {
uint64_t val;
/* Stop counting, and this also implies disabling STIMER0 */
wrmsr(MSR_HV_STIMER0_COUNT, 0);
val = rdmsr(MSR_HV_STIMER0_CONFIG);
if ((val & MSR_HV_STIMER_CFG_ENABLE) == 0)
break;
cpu_spinwait();
}
wrmsr(MSR_HV_STIMER0_CONFIG,
MSR_HV_STIMER_CFG_AUTOEN | MSR_HV_STIMER0_CFG_SINT);
}
static int
vmbus_et_attach(device_t dev)
{
/* TODO: use independent IDT vector */
vmbus_et.et_name = "Hyper-V";
vmbus_et.et_flags = ET_FLAGS_ONESHOT | ET_FLAGS_PERCPU;
vmbus_et.et_quality = 1000;
vmbus_et.et_frequency = HYPERV_TIMER_FREQ;
vmbus_et.et_min_period = (0x00000001ULL << 32) / HYPERV_TIMER_FREQ;
vmbus_et.et_max_period = (0xfffffffeULL << 32) / HYPERV_TIMER_FREQ;
vmbus_et.et_start = vmbus_et_start;
/*
* Delay a bit to make sure that MSR_HV_TIME_REF_COUNT will
* not return 0, since writing 0 to STIMER0_COUNT will disable
* STIMER0.
*/
DELAY(100);
smp_rendezvous(NULL, vmbus_et_config, NULL, NULL);
return (et_register(&vmbus_et));
}
static int
vmbus_et_detach(device_t dev)
{
return (et_deregister(&vmbus_et));
}