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qemu/hw/misc/mos6522.c
Laurent Vivier 6cf80f90c4 mos6522: update counters when timer interrupts are off 
Even if the interrupts are off, counters must be updated because
they are running anyway and kernel can try to read them
(it's the case with g3beige kernel).

Reported-by: Andrew Randrianasulu <randrianasulu@gmail.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20191125141414.5015-1-laurent@vivier.eu>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2019-11-26 10:11:50 +11:00

533 lines
15 KiB
C
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/*
* QEMU MOS6522 VIA emulation
*
* Copyright (c) 2004-2007 Fabrice Bellard
* Copyright (c) 2007 Jocelyn Mayer
* Copyright (c) 2018 Mark Cave-Ayland
*
* 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 "qemu/osdep.h"
#include "hw/input/adb.h"
#include "hw/irq.h"
#include "hw/misc/mos6522.h"
#include "hw/qdev-properties.h"
#include "migration/vmstate.h"
#include "qemu/timer.h"
#include "qemu/cutils.h"
#include "qemu/log.h"
#include "qemu/module.h"
#include "trace.h"
/* XXX: implement all timer modes */
static void mos6522_timer1_update(MOS6522State *s, MOS6522Timer *ti,
int64_t current_time);
static void mos6522_timer2_update(MOS6522State *s, MOS6522Timer *ti,
int64_t current_time);
static void mos6522_update_irq(MOS6522State *s)
{
if (s->ifr & s->ier) {
qemu_irq_raise(s->irq);
} else {
qemu_irq_lower(s->irq);
}
}
static uint64_t get_counter_value(MOS6522State *s, MOS6522Timer *ti)
{
MOS6522DeviceClass *mdc = MOS6522_DEVICE_GET_CLASS(s);
if (ti->index == 0) {
return mdc->get_timer1_counter_value(s, ti);
} else {
return mdc->get_timer2_counter_value(s, ti);
}
}
static uint64_t get_load_time(MOS6522State *s, MOS6522Timer *ti)
{
MOS6522DeviceClass *mdc = MOS6522_DEVICE_GET_CLASS(s);
if (ti->index == 0) {
return mdc->get_timer1_load_time(s, ti);
} else {
return mdc->get_timer2_load_time(s, ti);
}
}
static unsigned int get_counter(MOS6522State *s, MOS6522Timer *ti)
{
int64_t d;
unsigned int counter;
d = get_counter_value(s, ti);
if (ti->index == 0) {
/* the timer goes down from latch to -1 (period of latch + 2) */
if (d <= (ti->counter_value + 1)) {
counter = (ti->counter_value - d) & 0xffff;
} else {
counter = (d - (ti->counter_value + 1)) % (ti->latch + 2);
counter = (ti->latch - counter) & 0xffff;
}
} else {
counter = (ti->counter_value - d) & 0xffff;
}
return counter;
}
static void set_counter(MOS6522State *s, MOS6522Timer *ti, unsigned int val)
{
trace_mos6522_set_counter(1 + ti->index, val);
ti->load_time = get_load_time(s, ti);
ti->counter_value = val;
if (ti->index == 0) {
mos6522_timer1_update(s, ti, ti->load_time);
} else {
mos6522_timer2_update(s, ti, ti->load_time);
}
}
static int64_t get_next_irq_time(MOS6522State *s, MOS6522Timer *ti,
int64_t current_time)
{
int64_t d, next_time;
unsigned int counter;
if (ti->frequency == 0) {
return INT64_MAX;
}
/* current counter value */
d = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - ti->load_time,
ti->frequency, NANOSECONDS_PER_SECOND);
/* the timer goes down from latch to -1 (period of latch + 2) */
if (d <= (ti->counter_value + 1)) {
counter = (ti->counter_value - d) & 0xffff;
} else {
counter = (d - (ti->counter_value + 1)) % (ti->latch + 2);
counter = (ti->latch - counter) & 0xffff;
}
/* Note: we consider the irq is raised on 0 */
if (counter == 0xffff) {
next_time = d + ti->latch + 1;
} else if (counter == 0) {
next_time = d + ti->latch + 2;
} else {
next_time = d + counter;
}
trace_mos6522_get_next_irq_time(ti->latch, d, next_time - d);
next_time = muldiv64(next_time, NANOSECONDS_PER_SECOND, ti->frequency) +
ti->load_time;
if (next_time <= current_time) {
next_time = current_time + 1;
}
return next_time;
}
static void mos6522_timer1_update(MOS6522State *s, MOS6522Timer *ti,
int64_t current_time)
{
if (!ti->timer) {
return;
}
ti->next_irq_time = get_next_irq_time(s, ti, current_time);
if ((s->ier & T1_INT) == 0 || (s->acr & T1MODE) != T1MODE_CONT) {
timer_del(ti->timer);
} else {
timer_mod(ti->timer, ti->next_irq_time);
}
}
static void mos6522_timer2_update(MOS6522State *s, MOS6522Timer *ti,
int64_t current_time)
{
if (!ti->timer) {
return;
}
ti->next_irq_time = get_next_irq_time(s, ti, current_time);
if ((s->ier & T2_INT) == 0) {
timer_del(ti->timer);
} else {
timer_mod(ti->timer, ti->next_irq_time);
}
}
static void mos6522_timer1(void *opaque)
{
MOS6522State *s = opaque;
MOS6522Timer *ti = &s->timers[0];
mos6522_timer1_update(s, ti, ti->next_irq_time);
s->ifr |= T1_INT;
mos6522_update_irq(s);
}
static void mos6522_timer2(void *opaque)
{
MOS6522State *s = opaque;
MOS6522Timer *ti = &s->timers[1];
mos6522_timer2_update(s, ti, ti->next_irq_time);
s->ifr |= T2_INT;
mos6522_update_irq(s);
}
static void mos6522_set_sr_int(MOS6522State *s)
{
trace_mos6522_set_sr_int();
s->ifr |= SR_INT;
mos6522_update_irq(s);
}
static uint64_t mos6522_get_counter_value(MOS6522State *s, MOS6522Timer *ti)
{
return muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - ti->load_time,
ti->frequency, NANOSECONDS_PER_SECOND);
}
static uint64_t mos6522_get_load_time(MOS6522State *s, MOS6522Timer *ti)
{
uint64_t load_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
return load_time;
}
static void mos6522_portA_write(MOS6522State *s)
{
qemu_log_mask(LOG_UNIMP, "portA_write unimplemented\n");
}
static void mos6522_portB_write(MOS6522State *s)
{
qemu_log_mask(LOG_UNIMP, "portB_write unimplemented\n");
}
uint64_t mos6522_read(void *opaque, hwaddr addr, unsigned size)
{
MOS6522State *s = opaque;
uint32_t val;
int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
if (now >= s->timers[0].next_irq_time) {
mos6522_timer1_update(s, &s->timers[0], now);
s->ifr |= T1_INT;
}
if (now >= s->timers[1].next_irq_time) {
mos6522_timer2_update(s, &s->timers[1], now);
s->ifr |= T2_INT;
}
switch (addr) {
case VIA_REG_B:
val = s->b;
break;
case VIA_REG_A:
val = s->a;
break;
case VIA_REG_DIRB:
val = s->dirb;
break;
case VIA_REG_DIRA:
val = s->dira;
break;
case VIA_REG_T1CL:
val = get_counter(s, &s->timers[0]) & 0xff;
s->ifr &= ~T1_INT;
mos6522_update_irq(s);
break;
case VIA_REG_T1CH:
val = get_counter(s, &s->timers[0]) >> 8;
mos6522_update_irq(s);
break;
case VIA_REG_T1LL:
val = s->timers[0].latch & 0xff;
break;
case VIA_REG_T1LH:
/* XXX: check this */
val = (s->timers[0].latch >> 8) & 0xff;
break;
case VIA_REG_T2CL:
val = get_counter(s, &s->timers[1]) & 0xff;
s->ifr &= ~T2_INT;
mos6522_update_irq(s);
break;
case VIA_REG_T2CH:
val = get_counter(s, &s->timers[1]) >> 8;
break;
case VIA_REG_SR:
val = s->sr;
s->ifr &= ~SR_INT;
mos6522_update_irq(s);
break;
case VIA_REG_ACR:
val = s->acr;
break;
case VIA_REG_PCR:
val = s->pcr;
break;
case VIA_REG_IFR:
val = s->ifr;
if (s->ifr & s->ier) {
val |= 0x80;
}
break;
case VIA_REG_IER:
val = s->ier | 0x80;
break;
default:
case VIA_REG_ANH:
val = s->anh;
break;
}
if (addr != VIA_REG_IFR || val != 0) {
trace_mos6522_read(addr, val);
}
return val;
}
void mos6522_write(void *opaque, hwaddr addr, uint64_t val, unsigned size)
{
MOS6522State *s = opaque;
MOS6522DeviceClass *mdc = MOS6522_DEVICE_GET_CLASS(s);
trace_mos6522_write(addr, val);
switch (addr) {
case VIA_REG_B:
s->b = (s->b & ~s->dirb) | (val & s->dirb);
mdc->portB_write(s);
break;
case VIA_REG_A:
s->a = (s->a & ~s->dira) | (val & s->dira);
mdc->portA_write(s);
break;
case VIA_REG_DIRB:
s->dirb = val;
break;
case VIA_REG_DIRA:
s->dira = val;
break;
case VIA_REG_T1CL:
s->timers[0].latch = (s->timers[0].latch & 0xff00) | val;
mos6522_timer1_update(s, &s->timers[0],
qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
break;
case VIA_REG_T1CH:
s->timers[0].latch = (s->timers[0].latch & 0xff) | (val << 8);
s->ifr &= ~T1_INT;
set_counter(s, &s->timers[0], s->timers[0].latch);
break;
case VIA_REG_T1LL:
s->timers[0].latch = (s->timers[0].latch & 0xff00) | val;
mos6522_timer1_update(s, &s->timers[0],
qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
break;
case VIA_REG_T1LH:
s->timers[0].latch = (s->timers[0].latch & 0xff) | (val << 8);
s->ifr &= ~T1_INT;
mos6522_timer1_update(s, &s->timers[0],
qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
break;
case VIA_REG_T2CL:
s->timers[1].latch = (s->timers[1].latch & 0xff00) | val;
break;
case VIA_REG_T2CH:
/* To ensure T2 generates an interrupt on zero crossing with the
common timer code, write the value directly from the latch to
the counter */
s->timers[1].latch = (s->timers[1].latch & 0xff) | (val << 8);
s->ifr &= ~T2_INT;
set_counter(s, &s->timers[1], s->timers[1].latch);
break;
case VIA_REG_SR:
s->sr = val;
break;
case VIA_REG_ACR:
s->acr = val;
mos6522_timer1_update(s, &s->timers[0],
qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
break;
case VIA_REG_PCR:
s->pcr = val;
break;
case VIA_REG_IFR:
/* reset bits */
s->ifr &= ~val;
mos6522_update_irq(s);
break;
case VIA_REG_IER:
if (val & IER_SET) {
/* set bits */
s->ier |= val & 0x7f;
} else {
/* reset bits */
s->ier &= ~val;
}
mos6522_update_irq(s);
/* if IER is modified starts needed timers */
mos6522_timer1_update(s, &s->timers[0],
qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
mos6522_timer2_update(s, &s->timers[1],
qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
break;
default:
case VIA_REG_ANH:
s->anh = val;
break;
}
}
static const MemoryRegionOps mos6522_ops = {
.read = mos6522_read,
.write = mos6522_write,
.endianness = DEVICE_NATIVE_ENDIAN,
.valid = {
.min_access_size = 1,
.max_access_size = 1,
},
};
static const VMStateDescription vmstate_mos6522_timer = {
.name = "mos6522_timer",
.version_id = 0,
.minimum_version_id = 0,
.fields = (VMStateField[]) {
VMSTATE_UINT16(latch, MOS6522Timer),
VMSTATE_UINT16(counter_value, MOS6522Timer),
VMSTATE_INT64(load_time, MOS6522Timer),
VMSTATE_INT64(next_irq_time, MOS6522Timer),
VMSTATE_TIMER_PTR(timer, MOS6522Timer),
VMSTATE_END_OF_LIST()
}
};
const VMStateDescription vmstate_mos6522 = {
.name = "mos6522",
.version_id = 0,
.minimum_version_id = 0,
.fields = (VMStateField[]) {
VMSTATE_UINT8(a, MOS6522State),
VMSTATE_UINT8(b, MOS6522State),
VMSTATE_UINT8(dira, MOS6522State),
VMSTATE_UINT8(dirb, MOS6522State),
VMSTATE_UINT8(sr, MOS6522State),
VMSTATE_UINT8(acr, MOS6522State),
VMSTATE_UINT8(pcr, MOS6522State),
VMSTATE_UINT8(ifr, MOS6522State),
VMSTATE_UINT8(ier, MOS6522State),
VMSTATE_UINT8(anh, MOS6522State),
VMSTATE_STRUCT_ARRAY(timers, MOS6522State, 2, 0,
vmstate_mos6522_timer, MOS6522Timer),
VMSTATE_END_OF_LIST()
}
};
static void mos6522_reset(DeviceState *dev)
{
MOS6522State *s = MOS6522(dev);
s->b = 0;
s->a = 0;
s->dirb = 0xff;
s->dira = 0;
s->sr = 0;
s->acr = 0;
s->pcr = 0;
s->ifr = 0;
s->ier = 0;
/* s->ier = T1_INT | SR_INT; */
s->anh = 0;
s->timers[0].frequency = s->frequency;
s->timers[0].latch = 0xffff;
set_counter(s, &s->timers[0], 0xffff);
timer_del(s->timers[0].timer);
s->timers[1].frequency = s->frequency;
s->timers[1].latch = 0xffff;
timer_del(s->timers[1].timer);
}
static void mos6522_init(Object *obj)
{
SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
MOS6522State *s = MOS6522(obj);
int i;
memory_region_init_io(&s->mem, obj, &mos6522_ops, s, "mos6522", 0x10);
sysbus_init_mmio(sbd, &s->mem);
sysbus_init_irq(sbd, &s->irq);
for (i = 0; i < ARRAY_SIZE(s->timers); i++) {
s->timers[i].index = i;
}
s->timers[0].timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, mos6522_timer1, s);
s->timers[1].timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, mos6522_timer2, s);
}
static Property mos6522_properties[] = {
DEFINE_PROP_UINT64("frequency", MOS6522State, frequency, 0),
DEFINE_PROP_END_OF_LIST()
};
static void mos6522_class_init(ObjectClass *oc, void *data)
{
DeviceClass *dc = DEVICE_CLASS(oc);
MOS6522DeviceClass *mdc = MOS6522_DEVICE_CLASS(oc);
dc->reset = mos6522_reset;
dc->vmsd = &vmstate_mos6522;
dc->props = mos6522_properties;
mdc->parent_reset = dc->reset;
mdc->set_sr_int = mos6522_set_sr_int;
mdc->portB_write = mos6522_portB_write;
mdc->portA_write = mos6522_portA_write;
mdc->update_irq = mos6522_update_irq;
mdc->get_timer1_counter_value = mos6522_get_counter_value;
mdc->get_timer2_counter_value = mos6522_get_counter_value;
mdc->get_timer1_load_time = mos6522_get_load_time;
mdc->get_timer2_load_time = mos6522_get_load_time;
}
static const TypeInfo mos6522_type_info = {
.name = TYPE_MOS6522,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(MOS6522State),
.instance_init = mos6522_init,
.abstract = true,
.class_size = sizeof(MOS6522DeviceClass),
.class_init = mos6522_class_init,
};
static void mos6522_register_types(void)
{
type_register_static(&mos6522_type_info);
}
type_init(mos6522_register_types)
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