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/*
* QEMU OpenRISC timer support
*
* Copyright (c) 2011-2012 Jia Liu <proljc@gmail.com>
* Zhizhou Zhang <etouzh@gmail.com>
*
* 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 2.1 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/>.
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "migration/vmstate.h"
#include "qemu/timer.h"
#include "system/reset.h"
#define TIMER_PERIOD 50 /* 50 ns period for 20 MHz timer */
/* Tick Timer global state to allow all cores to be in sync */
typedef struct OR1KTimerState {
uint32_t ttcr;
uint32_t ttcr_offset;
uint64_t clk_offset;
} OR1KTimerState;
static OR1KTimerState *or1k_timer;
void cpu_openrisc_count_set(OpenRISCCPU *cpu, uint32_t val)
{
or1k_timer->ttcr = val;
or1k_timer->ttcr_offset = val;
or1k_timer->clk_offset = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
}
uint32_t cpu_openrisc_count_get(OpenRISCCPU *cpu)
{
return or1k_timer->ttcr;
}
/* Add elapsed ticks to ttcr */
void cpu_openrisc_count_update(OpenRISCCPU *cpu)
{
uint64_t now;
if (!cpu->env.is_counting) {
return;
}
now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
or1k_timer->ttcr = or1k_timer->ttcr_offset +
DIV_ROUND_UP(now - or1k_timer->clk_offset, TIMER_PERIOD);
}
/* Update the next timeout time as difference between ttmr and ttcr */
void cpu_openrisc_timer_update(OpenRISCCPU *cpu)
{
uint32_t wait;
uint64_t now, next;
if (!cpu->env.is_counting) {
return;
}
cpu_openrisc_count_update(cpu);
now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
if ((cpu->env.ttmr & TTMR_TP) <= (or1k_timer->ttcr & TTMR_TP)) {
wait = TTMR_TP - (or1k_timer->ttcr & TTMR_TP) + 1;
wait += cpu->env.ttmr & TTMR_TP;
} else {
wait = (cpu->env.ttmr & TTMR_TP) - (or1k_timer->ttcr & TTMR_TP);
}
next = now + (uint64_t)wait * TIMER_PERIOD;
timer_mod(cpu->env.timer, next);
}
void cpu_openrisc_count_start(OpenRISCCPU *cpu)
{
cpu->env.is_counting = 1;
cpu_openrisc_count_update(cpu);
}
void cpu_openrisc_count_stop(OpenRISCCPU *cpu)
{
timer_del(cpu->env.timer);
cpu_openrisc_count_update(cpu);
cpu->env.is_counting = 0;
}
static void openrisc_timer_cb(void *opaque)
{
OpenRISCCPU *cpu = opaque;
if ((cpu->env.ttmr & TTMR_IE) &&
timer_expired(cpu->env.timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL))) {
CPUState *cs = CPU(cpu);
cpu->env.ttmr |= TTMR_IP;
cs->interrupt_request |= CPU_INTERRUPT_TIMER;
}
switch (cpu->env.ttmr & TTMR_M) {
case TIMER_NONE:
break;
case TIMER_INTR:
/* Zero the count by applying a negative offset to the counter */
or1k_timer->ttcr_offset -= (cpu->env.ttmr & TTMR_TP);
break;
case TIMER_SHOT:
cpu_openrisc_count_stop(cpu);
break;
case TIMER_CONT:
break;
}
cpu_openrisc_timer_update(cpu);
qemu_cpu_kick(CPU(cpu));
}
/* Reset the per CPU counter state. */
static void openrisc_count_reset(void *opaque)
{
OpenRISCCPU *cpu = opaque;
if (cpu->env.is_counting) {
cpu_openrisc_count_stop(cpu);
}
cpu->env.ttmr = 0x00000000;
}
/* Reset the global timer state. */
static void openrisc_timer_reset(void *opaque)
{
OpenRISCCPU *cpu = opaque;
cpu_openrisc_count_set(cpu, 0);
}
static const VMStateDescription vmstate_or1k_timer = {
.name = "or1k_timer",
.version_id = 2,
.minimum_version_id = 2,
.fields = (const VMStateField[]) {
VMSTATE_UINT32(ttcr, OR1KTimerState),
VMSTATE_UINT32(ttcr_offset, OR1KTimerState),
VMSTATE_UINT64(clk_offset, OR1KTimerState),
VMSTATE_END_OF_LIST()
}
};
void cpu_openrisc_clock_init(OpenRISCCPU *cpu)
{
cpu->env.timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &openrisc_timer_cb, cpu);
qemu_register_reset(openrisc_count_reset, cpu);
if (or1k_timer == NULL) {
or1k_timer = g_new0(OR1KTimerState, 1);
qemu_register_reset(openrisc_timer_reset, cpu);
vmstate_register(NULL, 0, &vmstate_or1k_timer, or1k_timer);
}
}
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