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incubator-nuttx/include/nuttx/clock.h

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/****************************************************************************
* include/nuttx/clock.h
*
* Copyright (C) 2007-2009, 2011-2012, 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 _INCLUDE_NUTTX_CLOCK_H
#define _INCLUDE_NUTTX_CLOCK_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <time.h>
#include <nuttx/compiler.h>
/****************************************************************************
* Pre-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. We are not running tick-less (in which case there is no global timer
* data),
* 2. This is an un-protected, non-kernel build,
* 3. This is a protected build, but this code is being built for execution
* within the kernel space.
* 4. It we are building with SYSCALLs enabled, but not in a kernel build,
* then we can't know a priori whether the code has access to the
* global variables or not. In that case we have to assume not.
*/
#undef __HAVE_KERNEL_GLOBALS
#if defined(CONFIG_SCHED_TICKLESS)
/* Case 1: There is no global timer data */
# define __HAVE_KERNEL_GLOBALS 0
#elif defined(CONFIG_NUTTX_KERNEL)
# if defined(__KERNEL__)
/* Case 3: Kernel mode of protected kernel build */
# define __HAVE_KERNEL_GLOBALS 1
# else
/* User mode of protected kernel build */
# define __HAVE_KERNEL_GLOBALS 0
# endif
#elif defined(CONFIG_LIB_SYSCALL)
/* Case 4: Building with SYSCALLs enabled, but not part of a kernel build */
# define __HAVE_KERNEL_GLOBALS 0
#else
/* Case 2: Un-protected, non-kernel build */
# define __HAVE_KERNEL_GLOBALS 1
#endif
/* If CONFIG_SYSTEM_TIME64 is selected and the CPU supports long long types,
* then a 64-bit system time will be used.
*/
#ifndef CONFIG_HAVE_LONG_LONG
# undef CONFIG_SYSTEM_TIME64
#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
/* If CONFIG_SCHED_TICKLESS is not defined, then the interrupt interval of
* the system timer is given by USEC_PER_TICK. This is the expected number
* of microseconds between calls from the processor-specific logic to
* sched_process_timer(). The default value of USEC_PER_TICK is 10000
* microseconds (100KHz). However, this default setting can be overridden
* by defining the interval in microseconds as CONFIG_USEC_PER_TICK in the
* NuttX 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 microseconds. If (2) is not true, you will probably want
* to redefine all of the following.
*/
#ifdef CONFIG_USEC_PER_TICK
# define USEC_PER_TICK (CONFIG_USEC_PER_TICK)
#else
# define USEC_PER_TICK (10000)
#endif
/* MSEC_PER_TICK can be very inaccurate if CONFIG_USEC_PER_TICK is not an
* even multiple of milliseconds. Calculations using USEC_PER_TICK are
* preferred for that reason (at the risk of overflow)
*/
#define TICK_PER_DSEC (USEC_PER_DSEC / USEC_PER_TICK) /* Truncates! */
#define TICK_PER_SEC (USEC_PER_SEC / USEC_PER_TICK) /* Truncates! */
#define TICK_PER_MSEC (USEC_PER_MSEC / USEC_PER_TICK) /* Truncates! */
#define MSEC_PER_TICK (USEC_PER_TICK / USEC_PER_MSEC) /* Truncates! */
#define NSEC_PER_TICK (USEC_PER_TICK * NSEC_PER_USEC) /* 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 */
#if (MSEC_PER_TICK * USEC_PER_MSEC) == USEC_PER_TICK
# define MSEC2TICK(msec) (((msec)+(MSEC_PER_TICK/2))/MSEC_PER_TICK) /* Rounds */
#else
# define MSEC2TICK(msec) USEC2TICK(msec * 1000) /* Rounds */
#endif
#define DSEC2TICK(dsec) MSEC2TICK((dsec) * MSEC_PER_DSEC) /* Rounds */
#define SEC2TICK(sec) MSEC2TICK((sec) * MSEC_PER_SEC) /* Rounds */
#define TICK2NSEC(tick) ((tick) * NSEC_PER_TICK) /* Exact */
#define TICK2USEC(tick) ((tick) * USEC_PER_TICK) /* Exact */
#if (MSEC_PER_TICK * USEC_PER_MSEC) == USEC_PER_TICK
# define TICK2MSEC(tick) ((tick)*MSEC_PER_TICK) /* Exact */
#else
# define TICK2MSEC(tick) (((tick)*USEC_PER_TICK)/USEC_PER_MSEC) /* Rounds */
#endif
#define TICK2DSEC(tick) (((tick)+(TICK_PER_DSEC/2))/TICK_PER_DSEC) /* Rounds */
#define TICK2SEC(tick) (((tick)+(TICK_PER_SEC/2))/TICK_PER_SEC) /* Rounds */
/****************************************************************************
* Public Types
****************************************************************************/
/* This structure is used to report CPU usage for a particular thread */
#ifdef CONFIG_SCHED_CPULOAD
struct cpuload_s
{
volatile uint32_t total; /* Total number of clock ticks */
volatile uint32_t active; /* Number of ticks while this thread was active */
};
#endif
/****************************************************************************
* Public Data
****************************************************************************/
/* 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
# ifdef CONFIG_SYSTEM_TIME64
extern volatile uint64_t g_system_timer;
#define clock_systimer() (uint32_t)(g_system_timer & 0x00000000ffffffff)
#define clock_systimer64() g_system_timer
# else
extern volatile uint32_t g_system_timer;
#define clock_systimer() g_system_timer
# endif
#endif
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
/****************************************************************************
* Function: clock_synchronize
*
* Description:
* Synchronize the system timer to a hardware RTC. This operation is
* normally performed automatically by the system during clock
* initialization. However, the user may also need to explicitly re-
* synchronize the system timer to the RTC under certain conditions where
* the system timer is known to be in error. For example, in certain low-
* power states, the system timer may be stopped but the RTC will continue
* keep correct time. After recovering from such low-power state, this
* function should be called to restore the correct system time.
*
* Calling this function could result in system time going "backward" in
* time, especially with certain lower resolution RTC implementations.
* Time going backward could have bad consequences if there are ongoing
* timers and delays. So use this interface with care.
*
* Parameters:
* None
*
* Return Value:
* None
*
* Assumptions:
*
****************************************************************************/
#ifdef CONFIG_RTC
void clock_synchronize(void);
#endif
/****************************************************************************
* Function: clock_systimer
*
* Description:
* Return the current value of the 32-bit system timer counter. Indirect
* access to the system timer counter is required through this function if
* 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 !__HAVE_KERNEL_GLOBALS
# ifdef CONFIG_SYSTEM_TIME64
# define clock_systimer() (uint32_t)(clock_systimer64() & 0x00000000ffffffff)
# else
uint32_t clock_systimer(void);
# endif
#endif
/****************************************************************************
* Function: clock_systimer64
*
* Description:
* Return the current value of the 64-bit system timer counter. Indirect
* access to the system timer counter is required through this function if
* 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 !__HAVE_KERNEL_GLOBALS && defined(CONFIG_SYSTEM_TIME64)
uint64_t clock_systimer64(void);
#endif
/****************************************************************************
* Name: clock_systimespec
*
* Description:
* Return the current value of the system timer counter as a struct
* timespec.
*
* Parameters:
* ts - Location to return the time
*
* Return Value:
* Current version always returns OK
*
* Assumptions:
*
****************************************************************************/
int clock_systimespec(FAR struct timespec *ts);
/****************************************************************************
* Function: clock_cpuload
*
* Description:
* Return load measurement data for the select PID.
*
* Parameters:
* pid - The task ID of the thread of interest. pid == 0 is the IDLE thread.
* cpuload - The location to return the CPU load
*
* Return Value:
* OK (0) on success; a negated errno value on failure. The only reason
* that this function can fail is if 'pid' no longer refers to a valid
* thread.
*
* Assumptions:
*
****************************************************************************/
#ifdef CONFIG_SCHED_CPULOAD
int clock_cpuload(int pid, FAR struct cpuload_s *cpuload);
#endif
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* _INCLUDE_NUTTX_CLOCK_H */
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