133 lines
3.5 KiB
C
133 lines
3.5 KiB
C
/*
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* Copyright (c) 2014-2015 Wind River Systems, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* @file
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* @brief Variables needed needed for system clock
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*
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*
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* Declare variables used by both system timer device driver and kernel
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* components that use timer functionality.
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*/
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#ifndef _SYS_CLOCK__H_
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#define _SYS_CLOCK__H_
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#ifdef __cplusplus
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extern "C" {
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#endif
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#ifndef _ASMLANGUAGE
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#include <stdint.h>
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#if defined(CONFIG_SYS_CLOCK_EXISTS) && \
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(CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC == 0)
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#error "SYS_CLOCK_HW_CYCLES_PER_SEC must be non-zero!"
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#endif
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#define sys_clock_ticks_per_sec CONFIG_SYS_CLOCK_TICKS_PER_SEC
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#if defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME)
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extern int sys_clock_hw_cycles_per_sec;
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#else
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#define sys_clock_hw_cycles_per_sec CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC
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#endif
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/*
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* sys_clock_us_per_tick global variable represents a number
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* of microseconds in one OS timer tick
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*/
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extern int sys_clock_us_per_tick;
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/*
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* sys_clock_hw_cycles_per_tick global variable represents a number
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* of platform clock ticks in one OS timer tick.
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* sys_clock_hw_cycles_per_tick often represents a value of divider
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* of the board clock frequency
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*/
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extern int sys_clock_hw_cycles_per_tick;
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/* number of nsec per usec */
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#define NSEC_PER_USEC 1000
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/* number of microseconds per millisecond */
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#define USEC_PER_MSEC 1000
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/* number of milliseconds per second */
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#define MSEC_PER_SEC 1000
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/* number of microseconds per second */
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#define USEC_PER_SEC ((USEC_PER_MSEC) * (MSEC_PER_SEC))
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/* number of nanoseconds per second */
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#define NSEC_PER_SEC ((NSEC_PER_USEC) * (USEC_PER_MSEC) * (MSEC_PER_SEC))
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/* SYS_CLOCK_HW_CYCLES_TO_NS64 converts CPU clock cycles to nanoseconds */
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#define SYS_CLOCK_HW_CYCLES_TO_NS64(X) \
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(((uint64_t)(X) * sys_clock_us_per_tick * NSEC_PER_USEC) / \
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sys_clock_hw_cycles_per_tick)
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/*
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* SYS_CLOCK_HW_CYCLES_TO_NS_AVG converts CPU clock cycles to nanoseconds
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* and calculates the average cycle time
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*/
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#define SYS_CLOCK_HW_CYCLES_TO_NS_AVG(X, NCYCLES) \
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(uint32_t)(SYS_CLOCK_HW_CYCLES_TO_NS64(X) / NCYCLES)
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/**
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* @defgroup clock_apis Kernel Clock APIs
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* @ingroup kernel_apis
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* @{
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*/
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/**
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* @brief Compute nanoseconds from hardware clock cycles.
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*
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* This macro converts a time duration expressed in hardware clock cycles
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* to the equivalent duration expressed in nanoseconds.
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*
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* @param X Duration in hardware clock cycles.
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*
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* @return Duration in nanoseconds.
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*/
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#define SYS_CLOCK_HW_CYCLES_TO_NS(X) (uint32_t)(SYS_CLOCK_HW_CYCLES_TO_NS64(X))
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/**
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* @} end defgroup clock_apis
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*/
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extern int64_t _sys_clock_tick_count;
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/*
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* Number of ticks for x seconds. NOTE: With MSEC() or USEC(),
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* since it does an integer division, x must be greater or equal to
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* 1000/sys_clock_ticks_per_sec to get a non-zero value.
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* You may want to raise CONFIG_SYS_CLOCK_TICKS_PER_SEC depending on
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* your requirements.
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*/
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#define SECONDS(x) ((x) * sys_clock_ticks_per_sec)
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#define MSEC(x) (SECONDS(x) / MSEC_PER_SEC)
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#define USEC(x) (MSEC(x) / USEC_PER_MSEC)
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#endif /* !_ASMLANGUAGE */
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#ifdef __cplusplus
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}
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#endif
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#endif /* _SYS_CLOCK__H_ */
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