#include "hv/arch.h"
#include "hv/config.h"
#include "hv/timer.h"
#include "hv/uart.h"
#include "hv/vcpu.h"

static uint64_t g_cntfrq;

void timer_init(void)
{
    g_cntfrq = arch_cntfrq_el0();
}

uint64_t timer_now(void)
{
    return arch_cntpct_el0();
}

void timer_dump(void)
{
    uart_puts("timer cntfrq=");
    uart_put_dec64(g_cntfrq);
    uart_puts(" cntpct=");
    uart_put_dec64(timer_now());
    uart_puts("\n");
}

void timer_vcpu_sync(struct vcpu *vcpu)
{
    uint64_t now;
    if (vcpu == (struct vcpu *)0) {
        return;
    }

    vcpu->stats.timer_syncs++;
    now = timer_now();
    uint64_t ctl = vcpu->sysregs.cntv_ctl_el0;
    bool enabled = (ctl & 1u) != 0u;
    bool masked = (ctl & 2u) != 0u;
    if (!enabled || masked) {
        vcpu_clear_pending_irq(vcpu, CONFIG_VTIMER_IRQ);
        return;
    }

    if (now >= vcpu->sysregs.cntv_cval_el0) {
        vcpu->stats.timer_last_delta = now - vcpu->sysregs.cntv_cval_el0;
        vcpu->sysregs.cntv_ctl_el0 |= 4u;
        vcpu_set_pending_irq(vcpu, CONFIG_VTIMER_IRQ);
    } else {
        vcpu->stats.timer_last_delta = vcpu->sysregs.cntv_cval_el0 - now;
        vcpu->sysregs.cntv_ctl_el0 &= ~4ull;
        vcpu_clear_pending_irq(vcpu, CONFIG_VTIMER_IRQ);
    }
}