LXR qemu/target/loongarch/constant

   1/* SPDX-License-Identifier: GPL-2.0-or-later */
   2/*
   3 * QEMU LoongArch constant timer support
   4 *
   5 * Copyright (c) 2021 Loongson Technology Corporation Limited
   6 */
   7
   8#include "qemu/osdep.h"
   9#include "qemu/timer.h"
  10#include "cpu.h"
  11#include "internals.h"
  12#include "cpu-csr.h"
  13
  14#define TIMER_PERIOD                10 /* 10 ns period for 100 MHz frequency */
  15#define CONSTANT_TIMER_TICK_MASK    0xfffffffffffcUL
  16#define CONSTANT_TIMER_ENABLE       0x1UL
  17
  18uint64_t cpu_loongarch_get_constant_timer_counter(LoongArchCPU *cpu)
  19{
  20    return qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) / TIMER_PERIOD;
  21}
  22
  23uint64_t cpu_loongarch_get_constant_timer_ticks(LoongArchCPU *cpu)
  24{
  25    uint64_t now, expire;
  26
  27    now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
  28    expire = timer_expire_time_ns(&cpu->timer);
  29
  30    return (expire - now) / TIMER_PERIOD;
  31}
  32
  33void cpu_loongarch_store_constant_timer_config(LoongArchCPU *cpu,
  34                                               uint64_t value)
  35{
  36    CPULoongArchState *env = &cpu->env;
  37    uint64_t now, next;
  38
  39    env->CSR_TCFG = value;
  40    if (value & CONSTANT_TIMER_ENABLE) {
  41        now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
  42        next = now + (value & CONSTANT_TIMER_TICK_MASK) * TIMER_PERIOD;
  43        timer_mod(&cpu->timer, next);
  44    } else {
  45        timer_del(&cpu->timer);
  46    }
  47}
  48
  49void loongarch_constant_timer_cb(void *opaque)
  50{
  51    LoongArchCPU *cpu  = opaque;
  52    CPULoongArchState *env = &cpu->env;
  53    uint64_t now, next;
  54
  55    if (FIELD_EX64(env->CSR_TCFG, CSR_TCFG, PERIODIC)) {
  56        now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
  57        next = now + (env->CSR_TCFG & CONSTANT_TIMER_TICK_MASK) * TIMER_PERIOD;
  58        timer_mod(&cpu->timer, next);
  59    } else {
  60        env->CSR_TCFG = FIELD_DP64(env->CSR_TCFG, CSR_TCFG, EN, 0);
  61    }
  62
  63    loongarch_cpu_set_irq(opaque, IRQ_TIMER, 1);
  64}
  65