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walnux/include/nuttx/clock.h
patacongo 9ecda2e9fa More timer changes from Uros 
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3572 42af7a65-404d-4744-a932-0658087f49c3
2011-05-06 21:10:00 +00:00

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/****************************************************************************
* include/nuttx/clock.h
*
* Copyright (C) 2007-2009, 2011 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>
#include <stdint.h>
#include <time.h>
/****************************************************************************
* Pro-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
/* Efficient, direct access to OS global timer variables will be supported
* if the execution environment has direct access to kernel global data.
* The code in this execution context can access the kernel global data
* directly if: (1) this is an un-protected, non-kernel build, or (2)
* this code is being built for execution within the kernel.
*/
#undef __HAVE_KERNEL_GLOBALS
#if !defined(CONFIG_NUTTX_KERNEL) || defined(__KERNEL__)
# define __HAVE_KERNEL_GLOBALS 1
#else
# define __HAVE_KERNEL_GLOBALS 0
#endif
/* 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
****************************************************************************/
#if !defined(CONFIG_DISABLE_CLOCK)
/* Access to raw system clock ***********************************************/
/* Direct access to the system timer/counter is supported only if (1) the
* system timer counter is available (i.e., we are not configured to use
* a hardware periodic timer), and (2) the execution environment has direct
* access to kernel global data
*/
#if __HAVE_KERNEL_GLOBALS
extern volatile uint32_t g_system_timer;
extern volatile uint32_t g_system_utc;
#if TICK_PER_SEC > 32767
extern volatile uint32_t g_tickcount;
#elif TICK_PER_SEC > 255
extern volatile uint16_t g_tickcount;
#else
extern volatile uint8_t g_tickcount;
#endif
#endif /* __HAVE_KERNEL_GLOBALS */
#if !defined(CONFIG_SYSTEM_UTC) && __HAVE_KERNEL_GLOBALS
#define clock_systimer() g_system_timer
#endif
/****************************************************************************
* Global Function Prototypes
****************************************************************************/
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C" {
#else
#define EXTERN extern
#endif
/****************************************************************************
* Function: clock_systimer
*
* Description:
* Return the current value of the system timer counter. Indirect access
* to the system timer counter is required through this function if (1) we
* are using a hardware periodic timer, OR (2) the execution environment
* does not have direct access to kernel global data
*
* Parameters:
* None
*
* Return Value:
* The current value of the system timer counter
*
* Assumptions:
*
****************************************************************************/
#if defined(CONFIG_RTC) || !__HAVE_KERNEL_GLOBALS
EXTERN uint32_t clock_systimer(void);
#endif
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* !CONFIG_DISABLE_CLOCK */
#endif /* __NUTTX_CLOCK_H */
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