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vatpit.c
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/*-
* Copyright (c) 2014 Tycho Nightingale <tycho.nightingale@pluribusnetworks.com>
* Copyright (c) 2011 NetApp, Inc.
* Copyright (c) 2015 xhyve developers
* 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.
*/
#include <stdint.h>
#include <stdbool.h>
#include <assert.h>
#include <libkern/OSAtomic.h>
#include <xhyve/support/timerreg.h>
#include <xhyve/vmm/vmm_callout.h>
#include <xhyve/vmm/vmm_ktr.h>
#include <xhyve/vmm/io/vatpic.h>
#include <xhyve/vmm/io/vatpit.h>
#include <xhyve/vmm/io/vioapic.h>
#define VATPIT_LOCK_INIT(v) (v)->lock = OS_SPINLOCK_INIT;
#define VATPIT_LOCK(v) OSSpinLockLock(&(v)->lock)
#define VATPIT_UNLOCK(v) OSSpinLockUnlock(&(v)->lock)
#define TIMER_SEL_MASK 0xc0
#define TIMER_RW_MASK 0x30
#define TIMER_MODE_MASK 0x0f
#define TIMER_SEL_READBACK 0xc0
#define TIMER_STS_OUT 0x80
#define TIMER_STS_NULLCNT 0x40
#define TIMER_RB_LCTR 0x20
#define TIMER_RB_LSTATUS 0x10
#define TIMER_RB_CTR_2 0x08
#define TIMER_RB_CTR_1 0x04
#define TIMER_RB_CTR_0 0x02
#define TMR2_OUT_STS 0x20
#define PIT_8254_FREQ 1193182
#define TIMER_DIV(freq, hz) (((freq) + (hz) / 2) / (hz))
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wpadded"
struct vatpit_callout_arg {
struct vatpit *vatpit;
int channel_num;
};
struct channel {
int mode;
uint16_t initial; /* initial counter value */
sbintime_t now_sbt; /* uptime when counter was loaded */
uint8_t cr[2];
uint8_t ol[2];
bool slatched; /* status latched */
uint8_t status;
int crbyte;
int olbyte;
int frbyte;
struct callout callout;
sbintime_t callout_sbt; /* target time */
struct vatpit_callout_arg callout_arg;
};
struct vatpit {
struct vm *vm;
OSSpinLock lock;
sbintime_t freq_sbt;
struct channel channel[3];
};
#pragma clang diagnostic pop
static void pit_timer_start_cntr0(struct vatpit *vatpit);
static int
vatpit_get_out(struct vatpit *vatpit, int channel)
{
struct channel *c;
sbintime_t delta_ticks;
int out;
c = &vatpit->channel[channel];
switch (c->mode) {
case TIMER_INTTC:
delta_ticks = (sbinuptime() - c->now_sbt) / vatpit->freq_sbt;
out = ((c->initial - delta_ticks) <= 0);
break;
default:
out = 0;
break;
}
return (out);
}
static void
vatpit_callout_handler(void *a)
{
struct vatpit_callout_arg *arg = a;
struct vatpit *vatpit;
struct callout *callout;
struct channel *c;
vatpit = arg->vatpit;
c = &vatpit->channel[arg->channel_num];
callout = &c->callout;
VM_CTR1(vatpit->vm, "atpit t%d fired", arg->channel_num);
VATPIT_LOCK(vatpit);
if (callout_pending(callout)) /* callout was reset */
goto done;
if (!callout_active(callout)) /* callout was stopped */
goto done;
callout_deactivate(callout);
if (c->mode == TIMER_RATEGEN) {
pit_timer_start_cntr0(vatpit);
}
vatpic_pulse_irq(vatpit->vm, 0);
vioapic_pulse_irq(vatpit->vm, 2);
done:
VATPIT_UNLOCK(vatpit);
return;
}
static void
pit_timer_start_cntr0(struct vatpit *vatpit)
{
struct channel *c;
sbintime_t now, delta;
c = &vatpit->channel[0];
if (c->initial != 0) {
delta = c->initial * vatpit->freq_sbt;
c->callout_sbt = c->callout_sbt + delta;
/*
* Reset 'callout_sbt' if the time that the callout
* was supposed to fire is more than 'c->initial'
* ticks in the past.
*/
now = sbinuptime();
if (c->callout_sbt < now)
c->callout_sbt = now + delta;
callout_reset_sbt(&c->callout, c->callout_sbt,
0, vatpit_callout_handler, &c->callout_arg,
C_ABSOLUTE);
}
}
static uint16_t
pit_update_counter(struct vatpit *vatpit, struct channel *c, bool latch)
{
uint16_t lval;
sbintime_t delta_ticks;
/* cannot latch a new value until the old one has been consumed */
if (latch && c->olbyte != 0)
return (0);
if (c->initial == 0) {
/*
* This is possibly an o/s bug - reading the value of
* the timer without having set up the initial value.
*
* The original user-space version of this code set
* the timer to 100hz in this condition; do the same
* here.
*/
c->initial = TIMER_DIV(PIT_8254_FREQ, 100);
c->now_sbt = sbinuptime();
c->status &= ~TIMER_STS_NULLCNT;
}
delta_ticks = (sbinuptime() - c->now_sbt) / vatpit->freq_sbt;
lval = c->initial - delta_ticks % c->initial;
if (latch) {
c->olbyte = 2;
c->ol[1] = (uint8_t) lval; /* LSB */
c->ol[0] = (uint8_t) (lval >> 8); /* MSB */
}
return (lval);
}
static int
pit_readback1(struct vatpit *vatpit, int channel, uint8_t cmd)
{
struct channel *c;
c = &vatpit->channel[channel];
/*
* Latch the count/status of the timer if not already latched.
* N.B. that the count/status latch-select bits are active-low.
*/
if (!(cmd & TIMER_RB_LCTR) && !c->olbyte) {
(void) pit_update_counter(vatpit, c, true);
}
if (!(cmd & TIMER_RB_LSTATUS) && !c->slatched) {
c->slatched = true;
/*
* For mode 0, see if the elapsed time is greater
* than the initial value - this results in the
* output pin being set to 1 in the status byte.
*/
if (c->mode == TIMER_INTTC && vatpit_get_out(vatpit, channel))
c->status |= TIMER_STS_OUT;
else
c->status &= ~TIMER_STS_OUT;
}
return (0);
}
static int
pit_readback(struct vatpit *vatpit, uint8_t cmd)
{
int error;
/*
* The readback command can apply to all timers.
*/
error = 0;
if (cmd & TIMER_RB_CTR_0)
error = pit_readback1(vatpit, 0, cmd);
if (!error && cmd & TIMER_RB_CTR_1)
error = pit_readback1(vatpit, 1, cmd);
if (!error && cmd & TIMER_RB_CTR_2)
error = pit_readback1(vatpit, 2, cmd);
return (error);
}
static int
vatpit_update_mode(struct vatpit *vatpit, uint8_t val)
{
struct channel *c;
int sel, rw, mode;
sel = val & TIMER_SEL_MASK;
rw = val & TIMER_RW_MASK;
mode = val & TIMER_MODE_MASK;
if (sel == TIMER_SEL_READBACK)
return (pit_readback(vatpit, val));
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_INTTC &&
mode != TIMER_RATEGEN &&
mode != TIMER_SQWAVE &&
mode != TIMER_SWSTROBE)
return (-1);
}
c = &vatpit->channel[sel >> 6];
if (rw == TIMER_LATCH)
pit_update_counter(vatpit, c, true);
else {
c->mode = mode;
c->olbyte = 0; /* reset latch after reprogramming */
c->status |= TIMER_STS_NULLCNT;
}
return (0);
}
int
vatpit_handler(struct vm *vm, UNUSED int vcpuid, bool in, int port, int bytes,
uint32_t *eax)
{
struct vatpit *vatpit;
struct channel *c;
uint8_t val;
int error;
vatpit = vm_atpit(vm);
if (bytes != 1)
return (-1);
val = (uint8_t) *eax;
if (port == TIMER_MODE) {
if (in) {
VM_CTR0(vatpit->vm, "vatpit attempt to read mode");
return (-1);
}
VATPIT_LOCK(vatpit);
error = vatpit_update_mode(vatpit, val);
VATPIT_UNLOCK(vatpit);
return (error);
}
/* counter ports */
KASSERT(port >= TIMER_CNTR0 && port <= TIMER_CNTR2,
("invalid port 0x%x\n", port));
c = &vatpit->channel[port - TIMER_CNTR0];
VATPIT_LOCK(vatpit);
if (in && c->slatched) {
/*
* Return the status byte if latched
*/
*eax = c->status;
c->slatched = false;
c->status = 0;
} else if (in) {
/*
* The spec says that once the output latch is completely
* read it should revert to "following" the counter. Use
* the free running counter for this case (i.e. Linux
* TSC calibration). Assuming the access mode is 16-bit,
* toggle the MSB/LSB bit on each read.
*/
if (c->olbyte == 0) {
uint16_t tmp;
tmp = pit_update_counter(vatpit, c, false);
if (c->frbyte)
tmp >>= 8;
tmp &= 0xff;
*eax = tmp;
c->frbyte ^= 1;
} else
*eax = c->ol[--c->olbyte];
} else {
c->cr[c->crbyte++] = (uint8_t) *eax;
if (c->crbyte == 2) {
c->status &= ~TIMER_STS_NULLCNT;
c->frbyte = 0;
c->crbyte = 0;
c->initial = (uint16_t) c->cr[0];
c->initial |= (((uint16_t) c->cr[1]) << 8);
c->now_sbt = sbinuptime();
/* Start an interval timer for channel 0 */
if (port == TIMER_CNTR0) {
c->callout_sbt = c->now_sbt;
pit_timer_start_cntr0(vatpit);
}
if (c->initial == 0)
c->initial = 0xffff;
}
}
VATPIT_UNLOCK(vatpit);
return (0);
}
int
vatpit_nmisc_handler(struct vm *vm, UNUSED int vcpuid, bool in, UNUSED int port,
UNUSED int bytes, uint32_t *eax)
{
struct vatpit *vatpit;
vatpit = vm_atpit(vm);
if (in) {
VATPIT_LOCK(vatpit);
if (vatpit_get_out(vatpit, 2))
*eax = TMR2_OUT_STS;
else
*eax = 0;
VATPIT_UNLOCK(vatpit);
}
return (0);
}
struct vatpit *
vatpit_init(struct vm *vm)
{
struct vatpit *vatpit;
struct bintime bt;
struct vatpit_callout_arg *arg;
int i;
vatpit = malloc(sizeof(struct vatpit));
assert(vatpit);
bzero(vatpit, sizeof(struct vatpit));
vatpit->vm = vm;
VATPIT_LOCK_INIT(vatpit)
FREQ2BT(PIT_8254_FREQ, &bt);
vatpit->freq_sbt = bttosbt(bt);
for (i = 0; i < 3; i++) {
callout_init(&vatpit->channel[i].callout, true);
arg = &vatpit->channel[i].callout_arg;
arg->vatpit = vatpit;
arg->channel_num = i;
}
return (vatpit);
}
void
vatpit_cleanup(struct vatpit *vatpit)
{
int i;
for (i = 0; i < 3; i++)
callout_drain(&vatpit->channel[i].callout);
free(vatpit);
}