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qemu/hw/i8254.c
Jan Kiszka 8217606e6e Introduce reset notifier order 
Add the parameter 'order' to qemu_register_reset and sort callbacks on
registration. On system reset, callbacks with lower order will be
invoked before those with higher order. Update all existing users to the
standard order 0.

Note: At least for x86, the existing users seem to assume that handlers
are called in their registration order. Therefore, the patch preserves
this property. If someone feels bored, (s)he could try to identify this
dependency and express it properly on callback registration.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-05-22 10:50:34 -05:00

508 lines
13 KiB
C
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/*
* QEMU 8253/8254 interval timer emulation
*
* Copyright (c) 2003-2004 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "hw.h"
#include "pc.h"
#include "isa.h"
#include "qemu-timer.h"
//#define DEBUG_PIT
#define RW_STATE_LSB 1
#define RW_STATE_MSB 2
#define RW_STATE_WORD0 3
#define RW_STATE_WORD1 4
typedef struct PITChannelState {
int count; /* can be 65536 */
uint16_t latched_count;
uint8_t count_latched;
uint8_t status_latched;
uint8_t status;
uint8_t read_state;
uint8_t write_state;
uint8_t write_latch;
uint8_t rw_mode;
uint8_t mode;
uint8_t bcd; /* not supported */
uint8_t gate; /* timer start */
int64_t count_load_time;
/* irq handling */
int64_t next_transition_time;
QEMUTimer *irq_timer;
qemu_irq irq;
} PITChannelState;
struct PITState {
PITChannelState channels[3];
};
static PITState pit_state;
static void pit_irq_timer_update(PITChannelState *s, int64_t current_time);
static int pit_get_count(PITChannelState *s)
{
uint64_t d;
int counter;
d = muldiv64(qemu_get_clock(vm_clock) - s->count_load_time, PIT_FREQ, ticks_per_sec);
switch(s->mode) {
case 0:
case 1:
case 4:
case 5:
counter = (s->count - d) & 0xffff;
break;
case 3:
/* XXX: may be incorrect for odd counts */
counter = s->count - ((2 * d) % s->count);
break;
default:
counter = s->count - (d % s->count);
break;
}
return counter;
}
/* get pit output bit */
static int pit_get_out1(PITChannelState *s, int64_t current_time)
{
uint64_t d;
int out;
d = muldiv64(current_time - s->count_load_time, PIT_FREQ, ticks_per_sec);
switch(s->mode) {
default:
case 0:
out = (d >= s->count);
break;
case 1:
out = (d < s->count);
break;
case 2:
if ((d % s->count) == 0 && d != 0)
out = 1;
else
out = 0;
break;
case 3:
out = (d % s->count) < ((s->count + 1) >> 1);
break;
case 4:
case 5:
out = (d == s->count);
break;
}
return out;
}
int pit_get_out(PITState *pit, int channel, int64_t current_time)
{
PITChannelState *s = &pit->channels[channel];
return pit_get_out1(s, current_time);
}
/* return -1 if no transition will occur. */
static int64_t pit_get_next_transition_time(PITChannelState *s,
int64_t current_time)
{
uint64_t d, next_time, base;
int period2;
d = muldiv64(current_time - s->count_load_time, PIT_FREQ, ticks_per_sec);
switch(s->mode) {
default:
case 0:
case 1:
if (d < s->count)
next_time = s->count;
else
return -1;
break;
case 2:
base = (d / s->count) * s->count;
if ((d - base) == 0 && d != 0)
next_time = base + s->count;
else
next_time = base + s->count + 1;
break;
case 3:
base = (d / s->count) * s->count;
period2 = ((s->count + 1) >> 1);
if ((d - base) < period2)
next_time = base + period2;
else
next_time = base + s->count;
break;
case 4:
case 5:
if (d < s->count)
next_time = s->count;
else if (d == s->count)
next_time = s->count + 1;
else
return -1;
break;
}
/* convert to timer units */
next_time = s->count_load_time + muldiv64(next_time, ticks_per_sec, PIT_FREQ);
/* fix potential rounding problems */
/* XXX: better solution: use a clock at PIT_FREQ Hz */
if (next_time <= current_time)
next_time = current_time + 1;
return next_time;
}
/* val must be 0 or 1 */
void pit_set_gate(PITState *pit, int channel, int val)
{
PITChannelState *s = &pit->channels[channel];
switch(s->mode) {
default:
case 0:
case 4:
/* XXX: just disable/enable counting */
break;
case 1:
case 5:
if (s->gate < val) {
/* restart counting on rising edge */
s->count_load_time = qemu_get_clock(vm_clock);
pit_irq_timer_update(s, s->count_load_time);
}
break;
case 2:
case 3:
if (s->gate < val) {
/* restart counting on rising edge */
s->count_load_time = qemu_get_clock(vm_clock);
pit_irq_timer_update(s, s->count_load_time);
}
/* XXX: disable/enable counting */
break;
}
s->gate = val;
}
int pit_get_gate(PITState *pit, int channel)
{
PITChannelState *s = &pit->channels[channel];
return s->gate;
}
int pit_get_initial_count(PITState *pit, int channel)
{
PITChannelState *s = &pit->channels[channel];
return s->count;
}
int pit_get_mode(PITState *pit, int channel)
{
PITChannelState *s = &pit->channels[channel];
return s->mode;
}
static inline void pit_load_count(PITChannelState *s, int val)
{
if (val == 0)
val = 0x10000;
s->count_load_time = qemu_get_clock(vm_clock);
s->count = val;
pit_irq_timer_update(s, s->count_load_time);
}
/* if already latched, do not latch again */
static void pit_latch_count(PITChannelState *s)
{
if (!s->count_latched) {
s->latched_count = pit_get_count(s);
s->count_latched = s->rw_mode;
}
}
static void pit_ioport_write(void *opaque, uint32_t addr, uint32_t val)
{
PITState *pit = opaque;
int channel, access;
PITChannelState *s;
addr &= 3;
if (addr == 3) {
channel = val >> 6;
if (channel == 3) {
/* read back command */
for(channel = 0; channel < 3; channel++) {
s = &pit->channels[channel];
if (val & (2 << channel)) {
if (!(val & 0x20)) {
pit_latch_count(s);
}
if (!(val & 0x10) && !s->status_latched) {
/* status latch */
/* XXX: add BCD and null count */
s->status = (pit_get_out1(s, qemu_get_clock(vm_clock)) << 7) |
(s->rw_mode << 4) |
(s->mode << 1) |
s->bcd;
s->status_latched = 1;
}
}
}
} else {
s = &pit->channels[channel];
access = (val >> 4) & 3;
if (access == 0) {
pit_latch_count(s);
} else {
s->rw_mode = access;
s->read_state = access;
s->write_state = access;
s->mode = (val >> 1) & 7;
s->bcd = val & 1;
/* XXX: update irq timer ? */
}
}
} else {
s = &pit->channels[addr];
switch(s->write_state) {
default:
case RW_STATE_LSB:
pit_load_count(s, val);
break;
case RW_STATE_MSB:
pit_load_count(s, val << 8);
break;
case RW_STATE_WORD0:
s->write_latch = val;
s->write_state = RW_STATE_WORD1;
break;
case RW_STATE_WORD1:
pit_load_count(s, s->write_latch | (val << 8));
s->write_state = RW_STATE_WORD0;
break;
}
}
}
static uint32_t pit_ioport_read(void *opaque, uint32_t addr)
{
PITState *pit = opaque;
int ret, count;
PITChannelState *s;
addr &= 3;
s = &pit->channels[addr];
if (s->status_latched) {
s->status_latched = 0;
ret = s->status;
} else if (s->count_latched) {
switch(s->count_latched) {
default:
case RW_STATE_LSB:
ret = s->latched_count & 0xff;
s->count_latched = 0;
break;
case RW_STATE_MSB:
ret = s->latched_count >> 8;
s->count_latched = 0;
break;
case RW_STATE_WORD0:
ret = s->latched_count & 0xff;
s->count_latched = RW_STATE_MSB;
break;
}
} else {
switch(s->read_state) {
default:
case RW_STATE_LSB:
count = pit_get_count(s);
ret = count & 0xff;
break;
case RW_STATE_MSB:
count = pit_get_count(s);
ret = (count >> 8) & 0xff;
break;
case RW_STATE_WORD0:
count = pit_get_count(s);
ret = count & 0xff;
s->read_state = RW_STATE_WORD1;
break;
case RW_STATE_WORD1:
count = pit_get_count(s);
ret = (count >> 8) & 0xff;
s->read_state = RW_STATE_WORD0;
break;
}
}
return ret;
}
static void pit_irq_timer_update(PITChannelState *s, int64_t current_time)
{
int64_t expire_time;
int irq_level;
if (!s->irq_timer)
return;
expire_time = pit_get_next_transition_time(s, current_time);
irq_level = pit_get_out1(s, current_time);
qemu_set_irq(s->irq, irq_level);
#ifdef DEBUG_PIT
printf("irq_level=%d next_delay=%f\n",
irq_level,
(double)(expire_time - current_time) / ticks_per_sec);
#endif
s->next_transition_time = expire_time;
if (expire_time != -1)
qemu_mod_timer(s->irq_timer, expire_time);
else
qemu_del_timer(s->irq_timer);
}
static void pit_irq_timer(void *opaque)
{
PITChannelState *s = opaque;
pit_irq_timer_update(s, s->next_transition_time);
}
static void pit_save(QEMUFile *f, void *opaque)
{
PITState *pit = opaque;
PITChannelState *s;
int i;
for(i = 0; i < 3; i++) {
s = &pit->channels[i];
qemu_put_be32(f, s->count);
qemu_put_be16s(f, &s->latched_count);
qemu_put_8s(f, &s->count_latched);
qemu_put_8s(f, &s->status_latched);
qemu_put_8s(f, &s->status);
qemu_put_8s(f, &s->read_state);
qemu_put_8s(f, &s->write_state);
qemu_put_8s(f, &s->write_latch);
qemu_put_8s(f, &s->rw_mode);
qemu_put_8s(f, &s->mode);
qemu_put_8s(f, &s->bcd);
qemu_put_8s(f, &s->gate);
qemu_put_be64(f, s->count_load_time);
if (s->irq_timer) {
qemu_put_be64(f, s->next_transition_time);
qemu_put_timer(f, s->irq_timer);
}
}
}
static int pit_load(QEMUFile *f, void *opaque, int version_id)
{
PITState *pit = opaque;
PITChannelState *s;
int i;
if (version_id != 1)
return -EINVAL;
for(i = 0; i < 3; i++) {
s = &pit->channels[i];
s->count=qemu_get_be32(f);
qemu_get_be16s(f, &s->latched_count);
qemu_get_8s(f, &s->count_latched);
qemu_get_8s(f, &s->status_latched);
qemu_get_8s(f, &s->status);
qemu_get_8s(f, &s->read_state);
qemu_get_8s(f, &s->write_state);
qemu_get_8s(f, &s->write_latch);
qemu_get_8s(f, &s->rw_mode);
qemu_get_8s(f, &s->mode);
qemu_get_8s(f, &s->bcd);
qemu_get_8s(f, &s->gate);
s->count_load_time=qemu_get_be64(f);
if (s->irq_timer) {
s->next_transition_time=qemu_get_be64(f);
qemu_get_timer(f, s->irq_timer);
}
}
return 0;
}
static void pit_reset(void *opaque)
{
PITState *pit = opaque;
PITChannelState *s;
int i;
for(i = 0;i < 3; i++) {
s = &pit->channels[i];
s->mode = 3;
s->gate = (i != 2);
pit_load_count(s, 0);
}
}
/* When HPET is operating in legacy mode, i8254 timer0 is disabled */
void hpet_pit_disable(void) {
PITChannelState *s;
s = &pit_state.channels[0];
if (s->irq_timer)
qemu_del_timer(s->irq_timer);
}
/* When HPET is reset or leaving legacy mode, it must reenable i8254
* timer 0
*/
void hpet_pit_enable(void)
{
PITState *pit = &pit_state;
PITChannelState *s;
s = &pit->channels[0];
s->mode = 3;
s->gate = 1;
pit_load_count(s, 0);
}
PITState *pit_init(int base, qemu_irq irq)
{
PITState *pit = &pit_state;
PITChannelState *s;
s = &pit->channels[0];
/* the timer 0 is connected to an IRQ */
s->irq_timer = qemu_new_timer(vm_clock, pit_irq_timer, s);
s->irq = irq;
register_savevm("i8254", base, 1, pit_save, pit_load, pit);
qemu_register_reset(pit_reset, 0, pit);
register_ioport_write(base, 4, 1, pit_ioport_write, pit);
register_ioport_read(base, 3, 1, pit_ioport_read, pit);
pit_reset(pit);
return pit;
}
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