core/host/timer.c

/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

/* Timer module */

#include <stdint.h>
#include <stdio.h>
#include <time.h>

#include "task.h"
#include "test_util.h"
#include "timer.h"
#include "util.h"

/*
 * For test that need to test for longer than the default time limit,
 * adjust its time scale in test/build.mk by specifying
 * <test_name>-scale=<new scale>.
 */
#ifndef TEST_TIME_SCALE
#define TEST_TIME_SCALE 1
#endif

/*
 * To increase the stability of timing sensitive unit tests, slow
 * down the time by 10x. This only affects active run time (including
 * udelay() calls). To an unit test, the only effect is increased code
 * execution speed. However, this comes at the cost of prolonged test
 * run time for tests that use udelay(). Fortunately, most of our tests
 * use usleep/msleep, and for tests that use udelay(), we can scale
 * the time as mentioned above.
 */
#define TEST_TIME_SLOW_DOWN 10

static timestamp_t boot_time;
static int time_set;

void usleep(unsigned us)
{
	if (!task_start_called()) {
		udelay(us);
		return;
	}

	ASSERT(!in_interrupt_context() &&
	       task_get_current() != TASK_ID_INT_GEN);

	task_wait_event(us);
}

timestamp_t _get_time(void)
{
	struct timespec ts;
	timestamp_t ret;
	clock_gettime(CLOCK_MONOTONIC, &ts);
	ret.val = (1000000000 * (uint64_t)ts.tv_sec + ts.tv_nsec) *
		  TEST_TIME_SCALE / 1000 / TEST_TIME_SLOW_DOWN;
	return ret;
}

timestamp_t get_time(void)
{
	timestamp_t ret = _get_time();
	ret.val -= boot_time.val;
	return ret;
}

void force_time(timestamp_t ts)
{
	timestamp_t now = _get_time();
	boot_time.val = now.val - ts.val;
	time_set = 1;
}

void udelay(unsigned us)
{
	timestamp_t deadline;

	if (!in_interrupt_context() && task_get_current() == TASK_ID_INT_GEN) {
		interrupt_generator_udelay(us);
		return;
	}

	deadline.val = get_time().val + us;
	while (get_time().val < deadline.val)
		;
}

int timestamp_expired(timestamp_t deadline, const timestamp_t *now)
{
	timestamp_t now_val;

	if (!now) {
		now_val = get_time();
		now = &now_val;
	}

	return ((int64_t)(now->val - deadline.val) >= 0);
}

void timer_init(void)
{
	if (!time_set)
		boot_time = _get_time();
}