incubator-nuttx/include/nuttx/clock.h

130 lines
5.4 KiB
C

/****************************************************************************
* include/nuttx/clock.h
*
* Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 NuttX 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 OWNER 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.
*
****************************************************************************/
#ifndef __NUTTX_CLOCK_H
#define __NUTTX_CLOCK_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
/****************************************************************************
* Definitions
****************************************************************************/
/* Timing constants */
#define NSEC_PER_SEC 1000000000
#define USEC_PER_SEC 1000000
#define MSEC_PER_SEC 1000
#define DSEC_PER_SEC 10
#define NSEC_PER_DSEC 100000000
#define USEC_PER_DSEC 100000
#define MSEC_PER_DSEC 100
#define NSEC_PER_MSEC 1000000
#define USEC_PER_MSEC 1000
#define NSEC_PER_USEC 1000
/* The interrupt interval of the system timer is given by MSEC_PER_TICK.
* This is the expected number of milliseconds between calls from the
* processor-specific logic to sched_process_timer(). The default value
* of MSEC_PER_TICK is 10 milliseconds (100KHz). However, this default
* setting can be overridden by defining the interval in milliseconds as
* CONFIG_MSEC_PER_TICK in the board configuration file.
*
* The following calculations are only accurate when (1) there is no
* truncation involved and (2) the underlying system timer is an even
* multiple of milliseconds. If (2) is not true, you will probably want
* to redefine all of the following.
*/
#ifdef CONFIG_MSEC_PER_TICK
# define MSEC_PER_TICK (CONFIG_MSEC_PER_TICK)
#else
# define MSEC_PER_TICK (10)
#endif
#define TICK_PER_DSEC (MSEC_PER_DSEC / MSEC_PER_TICK) /* Truncates! */
#define TICK_PER_SEC (MSEC_PER_SEC / MSEC_PER_TICK) /* Truncates! */
#define NSEC_PER_TICK (MSEC_PER_TICK * NSEC_PER_MSEC) /* Exact */
#define USEC_PER_TICK (MSEC_PER_TICK * USEC_PER_MSEC) /* Exact */
#define NSEC2TICK(nsec) (((nsec)+(NSEC_PER_TICK/2))/NSEC_PER_TICK) /* Rounds */
#define USEC2TICK(usec) (((usec)+(USEC_PER_TICK/2))/USEC_PER_TICK) /* Rounds */
#define MSEC2TICK(msec) (((msec)+(MSEC_PER_TICK/2))/MSEC_PER_TICK) /* Rounds */
#define DSEC2TICK(dsec) MSEC2TICK((dsec)*MSEC_PER_DSEC)
#define SEC2TICK(sec) MSEC2TICK((sec)*MSEC_PER_SEC)
#define TICK2NSEC(tick) ((tick)*NSEC_PER_TICK) /* Exact */
#define TICK2USEC(tick) ((tick)*USEC_PER_TICK) /* Exact */
#define TICK2MSEC(tick) ((tick)*MSEC_PER_TICK) /* Exact */
#define TICK2DSEC(tick) (((tick)+(TICK_PER_DSEC/2))/TICK_PER_DSEC) /* Rounds */
#define TICK2SEC(tick) (((tick)+(TICK_PER_SEC/2))/TICK_PER_SEC) /* Rounds */
/****************************************************************************
* Global Data
****************************************************************************/
/* Access to raw system clock ***********************************************/
#ifndef CONFIG_DISABLE_CLOCK
extern volatile uint32 g_system_timer;
#endif
/****************************************************************************
* Global Function Prototypes
****************************************************************************/
/****************************************************************************
* Global Function Prototypes
****************************************************************************/
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C" {
#else
#define EXTERN extern
#endif
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* __NUTTX_CLOCK_H */