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* Copyright (c) 2014-2015 Wind River Systems, Inc.
*
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @file
* @brief Variables needed needed for system clock
*
*
* Declare variables used by both system timer device driver and kernel
* components that use timer functionality.
*/
#ifndef _SYS_CLOCK__H_
#define _SYS_CLOCK__H_
#ifdef __cplusplus
extern "C" {
#endif
#ifndef _ASMLANGUAGE
#include <zephyr/types.h>
#if defined(CONFIG_SYS_CLOCK_EXISTS) && \
(CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC == 0)
#error "SYS_CLOCK_HW_CYCLES_PER_SEC must be non-zero!"
#endif
#ifdef CONFIG_TICKLESS_KERNEL
#define sys_clock_ticks_per_sec \
(1000000 / (CONFIG_TICKLESS_KERNEL_TIME_UNIT_IN_MICRO_SECS))
extern int _sys_clock_always_on;
extern void _enable_sys_clock(void);
#else
#define sys_clock_ticks_per_sec CONFIG_SYS_CLOCK_TICKS_PER_SEC
#endif
#if defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME)
extern int sys_clock_hw_cycles_per_sec;
#else
#define sys_clock_hw_cycles_per_sec CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC
#endif
/*
* sys_clock_us_per_tick global variable represents a number
* of microseconds in one OS timer tick
*/
extern int sys_clock_us_per_tick;
/*
* sys_clock_hw_cycles_per_tick global variable represents a number
* of platform clock ticks in one OS timer tick.
* sys_clock_hw_cycles_per_tick often represents a value of divider
* of the board clock frequency
*/
extern int sys_clock_hw_cycles_per_tick;
/* number of nsec per usec */
#define NSEC_PER_USEC 1000
/* number of microseconds per millisecond */
#define USEC_PER_MSEC 1000
/* number of milliseconds per second */
#define MSEC_PER_SEC 1000
/* number of microseconds per second */
#define USEC_PER_SEC ((USEC_PER_MSEC) * (MSEC_PER_SEC))
/* number of nanoseconds per second */
#define NSEC_PER_SEC ((NSEC_PER_USEC) * (USEC_PER_MSEC) * (MSEC_PER_SEC))
/* SYS_CLOCK_HW_CYCLES_TO_NS64 converts CPU clock cycles to nanoseconds */
#define SYS_CLOCK_HW_CYCLES_TO_NS64(X) \
(((u64_t)(X) * sys_clock_us_per_tick * NSEC_PER_USEC) / \
sys_clock_hw_cycles_per_tick)
/*
* SYS_CLOCK_HW_CYCLES_TO_NS_AVG converts CPU clock cycles to nanoseconds
* and calculates the average cycle time
*/
#define SYS_CLOCK_HW_CYCLES_TO_NS_AVG(X, NCYCLES) \
(u32_t)(SYS_CLOCK_HW_CYCLES_TO_NS64(X) / NCYCLES)
/**
* @defgroup clock_apis Kernel Clock APIs
* @ingroup kernel_apis
* @{
*/
/**
* @brief Compute nanoseconds from hardware clock cycles.
*
* This macro converts a time duration expressed in hardware clock cycles
* to the equivalent duration expressed in nanoseconds.
*
* @param X Duration in hardware clock cycles.
*
* @return Duration in nanoseconds.
*/
#define SYS_CLOCK_HW_CYCLES_TO_NS(X) (u32_t)(SYS_CLOCK_HW_CYCLES_TO_NS64(X))
/**
* @} end defgroup clock_apis
*/
extern volatile u64_t _sys_clock_tick_count;
/*
* Number of ticks for x seconds. NOTE: With MSEC() or USEC(),
* since it does an integer division, x must be greater or equal to
* 1000/sys_clock_ticks_per_sec to get a non-zero value.
* You may want to raise CONFIG_SYS_CLOCK_TICKS_PER_SEC depending on
* your requirements.
*/
#define SECONDS(x) ((x) * sys_clock_ticks_per_sec)
#define MSEC(x) (SECONDS(x) / MSEC_PER_SEC)
#define USEC(x) (MSEC(x) / USEC_PER_MSEC)
#endif /* !_ASMLANGUAGE */
#ifdef __cplusplus
}
#endif
#endif /* _SYS_CLOCK__H_ */
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