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/**
* @file rtems/score/watchdog.h
*
* @brief Constants and Structures Associated with Watchdog Timers
*
* This include file contains all the constants and structures associated
* with watchdog timers. This Handler provides mechanisms which can be
* used to initialize and manipulate watchdog timers.
*/
/*
* COPYRIGHT (c) 1989-2009.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#ifndef _RTEMS_SCORE_WATCHDOG_H
#define _RTEMS_SCORE_WATCHDOG_H
#include <rtems/score/basedefs.h>
#include <rtems/score/chain.h>
#include <rtems/score/rbtree.h>
struct Per_CPU_Control;
#ifdef __cplusplus
extern "C" {
#endif
/**
* @defgroup ScoreWatchdog Watchdog Handler
*
* @ingroup Score
*
* This handler encapsulates functionality related to the scheduling of
* watchdog functions to be called at specific times in the future.
*
* @note This handler does not have anything to do with hardware watchdog
* timers.
*/
/**@{*/
typedef struct Watchdog_Control Watchdog_Control;
/**
* @brief Type is used to specify the length of intervals.
*
* This type is used to specify the length of intervals.
*/
typedef uint32_t Watchdog_Interval;
/**
* @brief The clock discipline to use for the Watchdog timeout interval.
*/
typedef enum {
/**
* @brief Indefinite wait.
*
* This is to indicate there is no timeout and not to use a watchdog. It
* must be equal to 0, which is an illegal relative clock interval, so that
* it may be used as a Watchdog_Interval value with WATCHDOG_RELATIVE to
* express an indefinite wait.
*/
WATCHDOG_NO_TIMEOUT = 0,
/**
* @brief Relative clock.
*
* The reference time point for the watchdog is current ticks value
* during insert. Time is measured in clock ticks.
*/
WATCHDOG_RELATIVE,
/**
* @brief Absolute clock.
*
* The reference time point for this header is the POSIX Epoch. Time is
* measured in nanoseconds since POSIX Epoch.
*/
WATCHDOG_ABSOLUTE
} Watchdog_Discipline;
/**
* @brief Return type from a Watchdog Service Routine.
*
* This type defines the return type from a Watchdog Service Routine.
*/
typedef void Watchdog_Service_routine;
/**
* @brief Pointer to a watchdog service routine.
*
* This type define a pointer to a watchdog service routine.
*/
typedef Watchdog_Service_routine
( *Watchdog_Service_routine_entry )( Watchdog_Control * );
/**
* @brief The watchdog header to manage scheduled watchdogs.
*/
typedef struct {
/**
* @brief Red-black tree of scheduled watchdogs sorted by expiration time.
*/
RBTree_Control Watchdogs;
/**
* @brief The scheduled watchdog with the earliest expiration time or NULL in
* case no watchdog is scheduled.
*/
RBTree_Node *first;
} Watchdog_Header;
/**
* @brief The control block used to manage each watchdog timer.
*
* The following record defines the control block used
* to manage each watchdog timer.
*/
struct Watchdog_Control {
/**
* @brief Nodes for the watchdog.
*/
union {
/**
* @brief this field is a red-black tree node structure and allows this to
* be placed on a red-black tree used to manage the scheduled watchdogs.
*/
RBTree_Node RBTree;
/**
* @brief this field is a chain node structure and allows this to be placed
* on a chain used to manage pending watchdogs by the timer server.
*/
Chain_Node Chain;
} Node;
#if defined(RTEMS_SMP)
/** @brief This field references the processor of this watchdog control. */
struct Per_CPU_Control *cpu;
#endif
/** @brief This field is the function to invoke. */
Watchdog_Service_routine_entry routine;
/** @brief This field is the expiration time point. */
uint64_t expire;
};
/**
* @brief The watchdog ticks counter.
*
* With a 1ms watchdog tick, this counter overflows after 50 days since boot.
*/
extern volatile Watchdog_Interval _Watchdog_Ticks_since_boot;
/**@}*/
#ifdef __cplusplus
}
#endif
#endif
/* end of include file */
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