subsys/timing/timing.c

/*
 * Copyright (c) 2020 Intel Corporation.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <stdbool.h>
#include <zephyr/kernel.h>
#include <zephyr/sys/atomic.h>
#include <zephyr/timing/timing.h>

static bool has_inited;
static atomic_val_t started_ref;

void timing_init(void)
{
	if (has_inited) {
		return;
	}

#if defined(CONFIG_BOARD_HAS_TIMING_FUNCTIONS)
	board_timing_init();
#elif defined(CONFIG_SOC_HAS_TIMING_FUNCTIONS)
	soc_timing_init();
#else
	arch_timing_init();
#endif

	has_inited = true;
}

void timing_start(void)
{
	if (atomic_inc(&started_ref) != 0) {
		return;
	}

#if defined(CONFIG_BOARD_HAS_TIMING_FUNCTIONS)
	board_timing_start();
#elif defined(CONFIG_SOC_HAS_TIMING_FUNCTIONS)
	soc_timing_start();
#else
	arch_timing_start();
#endif
}

void timing_stop(void)
{
	atomic_t old_value, new_value;

	/* Make sure this does decrement past zero. */
	do {
		old_value = atomic_get(&started_ref);
		if (old_value <= 0) {
			break;
		}

		new_value = old_value - 1;
	} while (atomic_cas(&started_ref, old_value, new_value) == 0);

	/*
	 * new_value may be uninitialized, so use old_value here.
	 */
	if (old_value > 1) {
		return;
	}

#if defined(CONFIG_BOARD_HAS_TIMING_FUNCTIONS)
	board_timing_stop();
#elif defined(CONFIG_SOC_HAS_TIMING_FUNCTIONS)
	soc_timing_stop();
#else
	arch_timing_stop();
#endif
}