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/*-
* Copyright (c) 2011 NetApp, Inc.
* 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 NETAPP, INC ``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 NETAPP, INC 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.
*
* $FreeBSD$
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/time.h>
#include <machine/clock.h>
#include <stdio.h>
#include <assert.h>
#include "bhyverun.h"
#include "inout.h"
#include "pit_8254.h"
#define TIMER_SEL_MASK 0xc0
#define TIMER_RW_MASK 0x30
#define TIMER_MODE_MASK 0x0f
#define TIMER_SEL_READBACK 0xc0
#define TIMER_DIV(freq, hz) (((freq) + (hz) / 2) / (hz))
#define PIT_8254_FREQ 1193182
static const int nsecs_per_tick = 1000000000 / PIT_8254_FREQ;
struct counter {
struct timeval tv; /* uptime when counter was loaded */
uint16_t initial; /* initial counter value */
uint8_t cr[2];
uint8_t ol[2];
int crbyte;
int olbyte;
};
static void
timevalfix(struct timeval *t1)
{
if (t1->tv_usec < 0) {
t1->tv_sec--;
t1->tv_usec += 1000000;
}
if (t1->tv_usec >= 1000000) {
t1->tv_sec++;
t1->tv_usec -= 1000000;
}
}
static void
timevalsub(struct timeval *t1, const struct timeval *t2)
{
t1->tv_sec -= t2->tv_sec;
t1->tv_usec -= t2->tv_usec;
timevalfix(t1);
}
static void
latch(struct counter *c)
{
struct timeval tv2;
uint16_t lval;
uint64_t delta_nsecs, delta_ticks;
/* cannot latch a new value until the old one has been consumed */
if (c->olbyte != 0)
return;
if (c->initial == 0 || c->initial == 1) {
/*
* XXX the program that runs the VM can be stopped and
* restarted at any time. This means that state that was
* created by the guest is destroyed between invocations
* of the program.
*
* If the counter's initial value is not programmed we
* assume a value that would be set to generate 'guest_hz'
* interrupts per second.
*/
c->initial = TIMER_DIV(PIT_8254_FREQ, guest_hz);
gettimeofday(&c->tv, NULL);
}
(void)gettimeofday(&tv2, NULL);
timevalsub(&tv2, &c->tv);
delta_nsecs = tv2.tv_sec * 1000000000 + tv2.tv_usec * 1000;
delta_ticks = delta_nsecs / nsecs_per_tick;
lval = c->initial - delta_ticks % c->initial;
c->olbyte = 2;
c->ol[1] = lval; /* LSB */
c->ol[0] = lval >> 8; /* MSB */
}
static int
pit_8254_handler(struct vmctx *ctx, int vcpu, int in, int port, int bytes,
uint32_t *eax, void *arg)
{
int sel, rw, mode;
uint8_t val;
struct counter *c;
static struct counter counter[3];
if (bytes != 1)
return (-1);
val = *eax;
if (port == TIMER_MODE) {
assert(in == 0);
sel = val & TIMER_SEL_MASK;
rw = val & TIMER_RW_MASK;
mode = val & TIMER_MODE_MASK;
if (sel == TIMER_SEL_READBACK)
return (-1);
if (rw != TIMER_LATCH && rw != TIMER_16BIT)
return (-1);
if (rw != TIMER_LATCH) {
/*
* Counter mode is not affected when issuing a
* latch command.
*/
if (mode != TIMER_RATEGEN && mode != TIMER_SQWAVE)
return (-1);
}
c = &counter[sel >> 6];
if (rw == TIMER_LATCH)
latch(c);
else
c->olbyte = 0; /* reset latch after reprogramming */
return (0);
}
/* counter ports */
assert(port >= TIMER_CNTR0 && port <= TIMER_CNTR2);
c = &counter[port - TIMER_CNTR0];
if (in) {
/*
* XXX
* The spec says that once the output latch is completely
* read it should revert to "following" the counter. We don't
* do this because it is hard and any reasonable OS should
* always latch the counter before trying to read it.
*/
if (c->olbyte == 0)
c->olbyte = 2;
*eax = c->ol[--c->olbyte];
} else {
c->cr[c->crbyte++] = *eax;
if (c->crbyte == 2) {
c->crbyte = 0;
c->initial = c->cr[0] | (uint16_t)c->cr[1] << 8;
if (c->initial == 0)
c->initial = 0xffff;
gettimeofday(&c->tv, NULL);
}
}
return (0);
}
INOUT_PORT(8254, TIMER_MODE, IOPORT_F_OUT, pit_8254_handler);
INOUT_PORT(8254, TIMER_CNTR0, IOPORT_F_INOUT, pit_8254_handler);
INOUT_PORT(8254, TIMER_CNTR1, IOPORT_F_INOUT, pit_8254_handler);
INOUT_PORT(8254, TIMER_CNTR2, IOPORT_F_INOUT, pit_8254_handler);
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