ac7304a758
to inject edge triggered legacy interrupts into the guest. Start using the new API in device models that use edge triggered interrupts: viz. the 8254 timer and the LPC/uart device emulation. Submitted by: Tycho Nightingale (tycho.nightingale@pluribusnetworks.com)
271 lines
6.2 KiB
C
271 lines
6.2 KiB
C
/*-
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* Copyright (c) 2011 NetApp, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <sys/time.h>
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#include <machine/vmm.h>
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#include <machine/clock.h>
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#include <assert.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <vmmapi.h>
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#include "bhyverun.h"
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#include "inout.h"
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#include "mevent.h"
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#include "pit_8254.h"
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#define TIMER_SEL_MASK 0xc0
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#define TIMER_RW_MASK 0x30
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#define TIMER_MODE_MASK 0x0f
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#define TIMER_SEL_READBACK 0xc0
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#define TIMER_DIV(freq, hz) (((freq) + (hz) / 2) / (hz))
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#define PIT_8254_FREQ 1193182
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static const int nsecs_per_tick = 1000000000 / PIT_8254_FREQ;
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struct counter {
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struct vmctx *ctx;
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struct mevent *tevp;
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struct timeval tv; /* uptime when counter was loaded */
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int mode;
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uint16_t initial; /* initial counter value */
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uint8_t cr[2];
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uint8_t ol[2];
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int crbyte;
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int olbyte;
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int frbyte;
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};
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static void
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timevalfix(struct timeval *t1)
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{
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if (t1->tv_usec < 0) {
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t1->tv_sec--;
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t1->tv_usec += 1000000;
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}
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if (t1->tv_usec >= 1000000) {
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t1->tv_sec++;
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t1->tv_usec -= 1000000;
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}
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}
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static void
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timevalsub(struct timeval *t1, const struct timeval *t2)
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{
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t1->tv_sec -= t2->tv_sec;
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t1->tv_usec -= t2->tv_usec;
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timevalfix(t1);
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}
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static uint64_t pit_mev_count;
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static void
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pit_mevent_cb(int fd, enum ev_type type, void *param)
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{
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struct counter *c;
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c = param;
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pit_mev_count++;
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vm_ioapic_pulse_irq(c->ctx, 2);
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/*
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* Delete the timer for one-shots
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*/
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if (c->mode != TIMER_RATEGEN) {
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mevent_delete(c->tevp);
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c->tevp = NULL;
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}
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}
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static void
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pit_timer_start(struct vmctx *ctx, struct counter *c)
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{
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int msecs;
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if (c->initial != 0) {
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msecs = c->initial * nsecs_per_tick / 1000000;
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if (msecs == 0)
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msecs = 1;
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if (c->tevp == NULL)
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c->tevp = mevent_add(msecs, EVF_TIMER, pit_mevent_cb,
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c);
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}
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}
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static uint16_t
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pit_update_counter(struct counter *c, int latch)
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{
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struct timeval tv2;
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uint16_t lval;
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uint64_t delta_nsecs, delta_ticks;
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/* cannot latch a new value until the old one has been consumed */
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if (latch && c->olbyte != 0)
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return (0);
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if (c->initial == 0 || c->initial == 1) {
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/*
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* XXX the program that runs the VM can be stopped and
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* restarted at any time. This means that state that was
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* created by the guest is destroyed between invocations
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* of the program.
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*
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* If the counter's initial value is not programmed we
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* assume a value that would be set to generate 100
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* interrupts per second.
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*/
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c->initial = TIMER_DIV(PIT_8254_FREQ, 100);
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gettimeofday(&c->tv, NULL);
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}
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(void)gettimeofday(&tv2, NULL);
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timevalsub(&tv2, &c->tv);
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delta_nsecs = tv2.tv_sec * 1000000000 + tv2.tv_usec * 1000;
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delta_ticks = delta_nsecs / nsecs_per_tick;
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lval = c->initial - delta_ticks % c->initial;
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if (latch) {
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c->olbyte = 2;
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c->ol[1] = lval; /* LSB */
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c->ol[0] = lval >> 8; /* MSB */
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}
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return (lval);
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}
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static int
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pit_8254_handler(struct vmctx *ctx, int vcpu, int in, int port, int bytes,
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uint32_t *eax, void *arg)
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{
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int sel, rw, mode;
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uint8_t val;
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struct counter *c;
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static struct counter counter[3];
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if (bytes != 1)
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return (-1);
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val = *eax;
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if (port == TIMER_MODE) {
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assert(in == 0);
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sel = val & TIMER_SEL_MASK;
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rw = val & TIMER_RW_MASK;
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mode = val & TIMER_MODE_MASK;
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if (sel == TIMER_SEL_READBACK)
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return (-1);
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if (rw != TIMER_LATCH && rw != TIMER_16BIT)
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return (-1);
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if (rw != TIMER_LATCH) {
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/*
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* Counter mode is not affected when issuing a
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* latch command.
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*/
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if (mode != TIMER_INTTC &&
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mode != TIMER_RATEGEN &&
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mode != TIMER_SQWAVE &&
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mode != TIMER_SWSTROBE)
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return (-1);
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}
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c = &counter[sel >> 6];
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c->ctx = ctx;
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c->mode = mode;
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if (rw == TIMER_LATCH)
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pit_update_counter(c, 1);
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else
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c->olbyte = 0; /* reset latch after reprogramming */
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return (0);
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}
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/* counter ports */
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assert(port >= TIMER_CNTR0 && port <= TIMER_CNTR2);
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c = &counter[port - TIMER_CNTR0];
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if (in) {
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/*
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* The spec says that once the output latch is completely
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* read it should revert to "following" the counter. Use
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* the free running counter for this case (i.e. Linux
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* TSC calibration). Assuming the access mode is 16-bit,
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* toggle the MSB/LSB bit on each read.
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*/
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if (c->olbyte == 0) {
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uint16_t tmp;
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tmp = pit_update_counter(c, 0);
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if (c->frbyte)
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tmp >>= 8;
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tmp &= 0xff;
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*eax = tmp;
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c->frbyte ^= 1;
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} else
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*eax = c->ol[--c->olbyte];
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} else {
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c->cr[c->crbyte++] = *eax;
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if (c->crbyte == 2) {
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c->frbyte = 0;
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c->crbyte = 0;
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c->initial = c->cr[0] | (uint16_t)c->cr[1] << 8;
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/* Start an interval timer for counter 0 */
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if (port == 0x40)
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pit_timer_start(ctx, c);
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if (c->initial == 0)
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c->initial = 0xffff;
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gettimeofday(&c->tv, NULL);
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}
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}
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return (0);
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}
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INOUT_PORT(8254, TIMER_MODE, IOPORT_F_OUT, pit_8254_handler);
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INOUT_PORT(8254, TIMER_CNTR0, IOPORT_F_INOUT, pit_8254_handler);
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INOUT_PORT(8254, TIMER_CNTR1, IOPORT_F_INOUT, pit_8254_handler);
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INOUT_PORT(8254, TIMER_CNTR2, IOPORT_F_INOUT, pit_8254_handler);
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