122 lines
4.9 KiB
C
122 lines
4.9 KiB
C
/****************************************************************************
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* nuttx/clock.h
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*
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* Copyright (C) 2007 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name Gregory Nutt nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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#ifndef __NUTTX_CLOCK_H
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#define __NUTTX_CLOCK_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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/****************************************************************************
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* Definitions
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****************************************************************************/
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/* Timing constants */
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#define NSEC_PER_SEC 1000000000
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#define USEC_PER_SEC 1000000
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#define MSEC_PER_SEC 1000
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#define DSEC_PER_SEC 10
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#define NSEC_PER_DSEC 100000000
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#define USEC_PER_DSEC 100000
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#define MSEC_PER_DSEC 100
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#define NSEC_PER_MSEC 1000000
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#define USEC_PER_MSEC 1000
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#define NSEC_PER_USEC 1000
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/* The interrupt interval of the system timer is given by MSEC_PER_TICK.
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* This is the expected number of milliseconds between calls from the
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* processor-specific logic to sched_process_timer(). The default value
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* of MSEC_PER_TICK is 10 milliseconds (100KHz). However, this default
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* setting can be overridden by defining the interval in milliseconds as
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* CONFIG_MSEC_PER_TICK in the board configuration file.
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*
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* The following calculations are only accurate when (1) there is no
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* truncation involved and (2) the underlying system timer is an even
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* multiple of milliseconds. If (2) is not true, you will probably want
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* to redefine all of the following.
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*/
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#ifdef CONFIG_MSEC_PER_TICK
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# define MSEC_PER_TICK (CONFIG_MSEC_PER_TICK)
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#else
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# define MSEC_PER_TICK (10)
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#endif
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#define TICK_PER_SEC (MSEC_PER_SEC / MSEC_PER_TICK) /* Truncates! */
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#define NSEC_PER_TICK (MSEC_PER_TICK * NSEC_PER_MSEC) /* Exact */
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#define USEC_PER_TICK (MSEC_PER_TICK * USEC_PER_MSEC) /* Exact */
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#define NSEC2TICK(nsec) (((nsec)+(NSEC_PER_TICK/2))/NSEC_PER_TICK) /* Rounds */
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#define USEC2TICK(usec) (((usec)+(USEC_PER_TICK/2))/USEC_PER_TICK) /* Rounds */
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#define MSEC2TICK(msec) (((msec)+(MSEC_PER_TICK/2))/MSEC_PER_TICK) /* Rounds */
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#define DSEC2TICK(dsec) MSEC2TICK((dsec)*MSEC_PER_DSEC)
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#define SEC2TICK(sec) MSEC2TICK((sec)*MSEC_PER_SEC)
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/****************************************************************************
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* Global Data
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****************************************************************************/
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/* Access to raw system clock ***********************************************/
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#ifndef CONFIG_DISABLE_CLOCK
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extern volatile uint32 g_system_timer;
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#endif
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/****************************************************************************
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* Global Function Prototypes
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****************************************************************************/
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/****************************************************************************
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* Global Function Prototypes
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****************************************************************************/
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#ifdef __cplusplus
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#define EXTERN extern "C"
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extern "C" {
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#else
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#define EXTERN extern
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#endif
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#undef EXTERN
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#ifdef __cplusplus
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}
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#endif
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#endif /* __NUTTX_CLOCK_H */
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