2 * Copyright (c) 2015,2016 Microsoft Corp.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/param.h>
32 #include <sys/kernel.h>
33 #include <sys/module.h>
36 #include <sys/systm.h>
37 #include <sys/timeet.h>
39 #include <machine/cpu.h>
41 #include <dev/hyperv/vmbus/hyperv_reg.h>
42 #include <dev/hyperv/vmbus/hyperv_var.h>
43 #include <dev/hyperv/vmbus/vmbus_var.h>
45 #define VMBUS_ET_NAME "hvet"
47 #define MSR_HV_STIMER0_CFG_SINT \
48 ((((uint64_t)VMBUS_SINT_TIMER) << MSR_HV_STIMER_CFG_SINT_SHIFT) & \
49 MSR_HV_STIMER_CFG_SINT_MASK)
52 * Two additionally required features:
53 * - SynIC is needed for interrupt generation.
54 * - Time reference counter is needed to set ABS reference count to
57 #define CPUID_HV_ET_MASK (CPUID_HV_MSR_TIME_REFCNT | \
58 CPUID_HV_MSR_SYNIC | \
59 CPUID_HV_MSR_SYNTIMER)
61 static void vmbus_et_identify(driver_t *, device_t);
62 static int vmbus_et_probe(device_t);
63 static int vmbus_et_attach(device_t);
64 static int vmbus_et_detach(device_t);
65 static int vmbus_et_start(struct eventtimer *, sbintime_t,
68 static struct eventtimer vmbus_et;
70 static device_method_t vmbus_et_methods[] = {
71 DEVMETHOD(device_identify, vmbus_et_identify),
72 DEVMETHOD(device_probe, vmbus_et_probe),
73 DEVMETHOD(device_attach, vmbus_et_attach),
74 DEVMETHOD(device_detach, vmbus_et_detach),
79 static driver_t vmbus_et_driver = {
85 static devclass_t vmbus_et_devclass;
87 DRIVER_MODULE(hv_et, vmbus, vmbus_et_driver, vmbus_et_devclass, NULL, NULL);
88 MODULE_VERSION(hv_et, 1);
90 static __inline uint64_t
91 hyperv_sbintime2count(sbintime_t time)
96 return (val.tv_sec * HYPERV_TIMER_FREQ) +
97 (val.tv_nsec / HYPERV_TIMER_NS_FACTOR);
101 vmbus_et_start(struct eventtimer *et __unused, sbintime_t first,
102 sbintime_t period __unused)
106 current = rdmsr(MSR_HV_TIME_REF_COUNT);
107 current += hyperv_sbintime2count(first);
108 wrmsr(MSR_HV_STIMER0_COUNT, current);
114 vmbus_et_intr(struct trapframe *frame)
116 struct trapframe *oldframe;
119 if (vmbus_et.et_active) {
121 td->td_intr_nesting_level++;
122 oldframe = td->td_intr_frame;
123 td->td_intr_frame = frame;
124 vmbus_et.et_event_cb(&vmbus_et, vmbus_et.et_arg);
125 td->td_intr_frame = oldframe;
126 td->td_intr_nesting_level--;
131 vmbus_et_identify(driver_t *driver, device_t parent)
133 if (device_get_unit(parent) != 0 ||
134 device_find_child(parent, VMBUS_ET_NAME, -1) != NULL ||
135 (hyperv_features & CPUID_HV_ET_MASK) != CPUID_HV_ET_MASK)
138 device_add_child(parent, VMBUS_ET_NAME, -1);
142 vmbus_et_probe(device_t dev)
144 if (resource_disabled(VMBUS_ET_NAME, 0))
147 device_set_desc(dev, "Hyper-V event timer");
149 return (BUS_PROBE_NOWILDCARD);
153 vmbus_et_config(void *arg __unused)
156 * Make sure that STIMER0 is really disabled before writing
159 * "Writing to the configuration register of a timer that
160 * is already enabled may result in undefined behaviour."
165 /* Stop counting, and this also implies disabling STIMER0 */
166 wrmsr(MSR_HV_STIMER0_COUNT, 0);
168 val = rdmsr(MSR_HV_STIMER0_CONFIG);
169 if ((val & MSR_HV_STIMER_CFG_ENABLE) == 0)
173 wrmsr(MSR_HV_STIMER0_CONFIG,
174 MSR_HV_STIMER_CFG_AUTOEN | MSR_HV_STIMER0_CFG_SINT);
178 vmbus_et_attach(device_t dev)
180 /* TODO: use independent IDT vector */
182 vmbus_et.et_name = "Hyper-V";
183 vmbus_et.et_flags = ET_FLAGS_ONESHOT | ET_FLAGS_PERCPU;
184 vmbus_et.et_quality = 1000;
185 vmbus_et.et_frequency = HYPERV_TIMER_FREQ;
186 vmbus_et.et_min_period = (0x00000001ULL << 32) / HYPERV_TIMER_FREQ;
187 vmbus_et.et_max_period = (0xfffffffeULL << 32) / HYPERV_TIMER_FREQ;
188 vmbus_et.et_start = vmbus_et_start;
191 * Delay a bit to make sure that MSR_HV_TIME_REF_COUNT will
192 * not return 0, since writing 0 to STIMER0_COUNT will disable
196 smp_rendezvous(NULL, vmbus_et_config, NULL, NULL);
198 return (et_register(&vmbus_et));
202 vmbus_et_detach(device_t dev)
204 return (et_deregister(&vmbus_et));