qemu/hw/lm32_timer.c

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/*
* QEMU model of the LatticeMico32 timer block.
*
* Copyright (c) 2010 Michael Walle <michael@walle.cc>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
*
* Specification available at:
* http://www.latticesemi.com/documents/mico32timer.pdf
*/
#include "hw.h"
#include "sysbus.h"
#include "trace.h"
#include "qemu-timer.h"
#include "qemu-error.h"
#define DEFAULT_FREQUENCY (50*1000000)
enum {
R_SR = 0,
R_CR,
R_PERIOD,
R_SNAPSHOT,
R_MAX
};
enum {
SR_TO = (1 << 0),
SR_RUN = (1 << 1),
};
enum {
CR_ITO = (1 << 0),
CR_CONT = (1 << 1),
CR_START = (1 << 2),
CR_STOP = (1 << 3),
};
struct LM32TimerState {
SysBusDevice busdev;
QEMUBH *bh;
ptimer_state *ptimer;
qemu_irq irq;
uint32_t freq_hz;
uint32_t regs[R_MAX];
};
typedef struct LM32TimerState LM32TimerState;
static void timer_update_irq(LM32TimerState *s)
{
int state = (s->regs[R_SR] & SR_TO) && (s->regs[R_CR] & CR_ITO);
trace_lm32_timer_irq_state(state);
qemu_set_irq(s->irq, state);
}
static uint32_t timer_read(void *opaque, target_phys_addr_t addr)
{
LM32TimerState *s = opaque;
uint32_t r = 0;
addr >>= 2;
switch (addr) {
case R_SR:
case R_CR:
case R_PERIOD:
r = s->regs[addr];
break;
case R_SNAPSHOT:
r = (uint32_t)ptimer_get_count(s->ptimer);
break;
default:
error_report("lm32_timer: read access to unknown register 0x"
TARGET_FMT_plx, addr << 2);
break;
}
trace_lm32_timer_memory_read(addr << 2, r);
return r;
}
static void timer_write(void *opaque, target_phys_addr_t addr, uint32_t value)
{
LM32TimerState *s = opaque;
trace_lm32_timer_memory_write(addr, value);
addr >>= 2;
switch (addr) {
case R_SR:
s->regs[R_SR] &= ~SR_TO;
break;
case R_CR:
s->regs[R_CR] = value;
if (s->regs[R_CR] & CR_START) {
ptimer_run(s->ptimer, 1);
}
if (s->regs[R_CR] & CR_STOP) {
ptimer_stop(s->ptimer);
}
break;
case R_PERIOD:
s->regs[R_PERIOD] = value;
ptimer_set_count(s->ptimer, value);
break;
case R_SNAPSHOT:
error_report("lm32_timer: write access to read only register 0x"
TARGET_FMT_plx, addr << 2);
break;
default:
error_report("lm32_timer: write access to unknown register 0x"
TARGET_FMT_plx, addr << 2);
break;
}
timer_update_irq(s);
}
static CPUReadMemoryFunc * const timer_read_fn[] = {
NULL,
NULL,
&timer_read,
};
static CPUWriteMemoryFunc * const timer_write_fn[] = {
NULL,
NULL,
&timer_write,
};
static void timer_hit(void *opaque)
{
LM32TimerState *s = opaque;
trace_lm32_timer_hit();
s->regs[R_SR] |= SR_TO;
if (s->regs[R_CR] & CR_CONT) {
ptimer_set_count(s->ptimer, s->regs[R_PERIOD]);
ptimer_run(s->ptimer, 1);
}
timer_update_irq(s);
}
static void timer_reset(DeviceState *d)
{
LM32TimerState *s = container_of(d, LM32TimerState, busdev.qdev);
int i;
for (i = 0; i < R_MAX; i++) {
s->regs[i] = 0;
}
ptimer_stop(s->ptimer);
}
static int lm32_timer_init(SysBusDevice *dev)
{
LM32TimerState *s = FROM_SYSBUS(typeof(*s), dev);
int timer_regs;
sysbus_init_irq(dev, &s->irq);
s->bh = qemu_bh_new(timer_hit, s);
s->ptimer = ptimer_init(s->bh);
ptimer_set_freq(s->ptimer, s->freq_hz);
timer_regs = cpu_register_io_memory(timer_read_fn, timer_write_fn, s,
DEVICE_NATIVE_ENDIAN);
sysbus_init_mmio(dev, R_MAX * 4, timer_regs);
return 0;
}
static const VMStateDescription vmstate_lm32_timer = {
.name = "lm32-timer",
.version_id = 1,
.minimum_version_id = 1,
.minimum_version_id_old = 1,
.fields = (VMStateField[]) {
VMSTATE_PTIMER(ptimer, LM32TimerState),
VMSTATE_UINT32(freq_hz, LM32TimerState),
VMSTATE_UINT32_ARRAY(regs, LM32TimerState, R_MAX),
VMSTATE_END_OF_LIST()
}
};
static SysBusDeviceInfo lm32_timer_info = {
.init = lm32_timer_init,
.qdev.name = "lm32-timer",
.qdev.size = sizeof(LM32TimerState),
.qdev.vmsd = &vmstate_lm32_timer,
.qdev.reset = timer_reset,
.qdev.props = (Property[]) {
DEFINE_PROP_UINT32(
"frequency", LM32TimerState, freq_hz, DEFAULT_FREQUENCY
),
DEFINE_PROP_END_OF_LIST(),
}
};
static void lm32_timer_register(void)
{
sysbus_register_withprop(&lm32_timer_info);
}
device_init(lm32_timer_register)