zephyr/include/clock_vars.h

88 lines
3.1 KiB
C

/* Variables needed needed for system clock */
/*
* Copyright (c) 2014-2015 Wind River Systems, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1) Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2) Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3) Neither the name of Wind River Systems nor the names of its contributors
* may be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
DESCRIPTION
Declare variables used by both system timer device driver and kernel components
that use timer functionality.
*/
#ifndef _CLOCK_VARS__H_
#define _CLOCK_VARS__H_
#ifndef _ASMLANGUAGE
#include <stdint.h>
#define sys_clock_ticks_per_sec CONFIG_SYS_CLOCK_TICKS_PER_SEC
#define sys_clock_hw_cycles_per_sec CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC
/*
* 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
/* SYS_CLOCK_HW_CYCLES_TO_NS64 converts CPU clock cycles to nanoseconds */
#define SYS_CLOCK_HW_CYCLES_TO_NS64(X) \
(((uint64_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) \
(uint32_t)(SYS_CLOCK_HW_CYCLES_TO_NS64 (X) / NCYCLES)
#define SYS_CLOCK_HW_CYCLES_TO_NS(X) (uint32_t)(SYS_CLOCK_HW_CYCLES_TO_NS64 (X))
#ifdef CONFIG_NANOKERNEL
extern uint32_t _nano_ticks;
extern struct nano_timer *_nano_timer_list;
#endif /* CONFIG_NANOKERNEL */
#endif /* !_ASMLANGUAGE */
#endif /* _CLOCK_VARS__H_ */