inc/hf/arch/timer.h

/*
 * Copyright 2018 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <stdbool.h>
#include <stdint.h>

#include "hf/arch/types.h"

/**
 * Sets the bit to mask virtual timer interrupts.
 */
void arch_timer_mask(struct arch_regs *regs);

/**
 * Checks whether the virtual timer is enabled and its interrupt not masked.
 */
bool arch_timer_enabled(struct arch_regs *regs);

/**
 * Returns the number of ticks remaining on the virtual timer as stored in
 * the given `arch_regs`, or 0 if it has already expired. This is undefined if
 * the timer is not enabled.
 */
uint64_t arch_timer_remaining_ticks(struct arch_regs *regs);

/**
 * Returns the number of nanoseconds remaining on the virtual timer as stored in
 * the given `arch_regs`, or 0 if it has already expired. This is undefined if
 * the timer is not enabled.
 */
uint64_t arch_timer_remaining_ns(struct arch_regs *regs);

/**
 * Returns whether the timer is ready to fire: i.e. it is enabled, not masked,
 * and the condition is met.
 */
bool arch_timer_pending(struct arch_regs *regs);

/**
 * Checks whether the virtual timer is enabled and its interrupt not masked, for
 * the currently active vCPU.
 */
bool arch_timer_enabled_current(void);

/**
 * Returns the number of ticks remaining on the virtual timer of the currently
 * active vCPU, or 0 if it has already expired. This is undefined if the timer
 * is not enabled.
 */
uint64_t arch_timer_remaining_ticks_current(void);

/**
 * Returns the number of nanoseconds remaining on the virtual timer of the
 * currently active vCPU, or 0 if it has already expired. This is undefined if
 * the timer is not enabled.
 */
uint64_t arch_timer_remaining_ns_current(void);