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/*  watchdog.h

 *

 *  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) 1989-1999.

 *  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.OARcorp.com/rtems/license.html.

 *

 *  $Id: watchdog.h,v 1.2 2001-09-27 11:59:32 chris Exp $

 */

#ifndef __WATCHDOG_h

#define __WATCHDOG_h

#ifdef __cplusplus

extern "C" {

#endif

#include <rtems/score/object.h>

/*

 *  The following type defines the control block used to manage

 *  intervals.

 */

typedef unsigned32 Watchdog_Interval;

/*

 *  The following types define a pointer to a watchdog service routine.

 */

typedef void Watchdog_Service_routine;

typedef Watchdog_Service_routine ( *Watchdog_Service_routine_entry )(

                 Objects_Id,

                 void *

             );

/*

 *  Constant for indefinite wait.  (actually an illegal interval)

 */

#define WATCHDOG_NO_TIMEOUT  0

/*

 *  The following enumerated type lists the states in which a

 *  watchdog timer may be at any given time.

 */

typedef enum {

  WATCHDOG_INACTIVE,       /* off all chains */

  WATCHDOG_BEING_INSERTED, /* off all chains, searching for insertion point */

  WATCHDOG_ACTIVE,         /* on chain, allowed to fire */

  WATCHDOG_REMOVE_IT       /* on chain, remove without firing if expires */

} Watchdog_States;

/*

 *  The following enumerated type details the manner in which

 *  a watchdog chain may be adjusted by the Watchdog_Adjust

 *  routine.  The direction indicates a movement FORWARD

 *  or BACKWARD in time.

 */

typedef enum {

  WATCHDOG_FORWARD,      /* adjust delta value forward */

  WATCHDOG_BACKWARD      /* adjust delta value backward */

} Watchdog_Adjust_directions;

/*

 *  The following record defines the control block used

 *  to manage each watchdog timer.

 */

typedef struct {

  Chain_Node                      Node;

  Watchdog_States                 state;

  Watchdog_Interval               initial;

  Watchdog_Interval               delta_interval;

  Watchdog_Interval               start_time;

  Watchdog_Interval               stop_time;

  Watchdog_Service_routine_entry  routine;

  Objects_Id                      id;

  void                           *user_data;

}   Watchdog_Control;

/*

 *  The following are used for synchronization purposes

 *  during an insert on a watchdog delta chain.

 */

SCORE_EXTERN volatile unsigned32  _Watchdog_Sync_level;

SCORE_EXTERN volatile unsigned32  _Watchdog_Sync_count;

/*

 *  The following contains the number of ticks since the

 *  system was booted.

 */

SCORE_EXTERN Watchdog_Interval _Watchdog_Ticks_since_boot;

/*

 *  The following defines the watchdog chains which are managed

 *  on ticks and second boundaries.

 */

SCORE_EXTERN Chain_Control _Watchdog_Ticks_chain;

SCORE_EXTERN Chain_Control _Watchdog_Seconds_chain;

/*

 *  _Watchdog_Handler_initialization

 *

 *  DESCRIPTION:

 *

 *  This routine initializes the watchdog handler.  The watchdog

 *  synchronization flag is initialized and the watchdog chains are

 *  initialized and emptied.

 */

void _Watchdog_Handler_initialization( void );

/*

 *  _Watchdog_Remove

 *

 *  DESCRIPTION:

 *

 *  This routine removes THE_WATCHDOG from the watchdog chain on which

 *  it resides and returns the state THE_WATCHDOG timer was in.

 */

Watchdog_States _Watchdog_Remove (

  Watchdog_Control *the_watchdog

);

/*

 *  _Watchdog_Adjust

 *

 *  DESCRIPTION:

 *

 *  This routine adjusts the HEADER watchdog chain in the forward

 *  or backward DIRECTION for UNITS ticks.

 */

void _Watchdog_Adjust (

  Chain_Control              *header,

  Watchdog_Adjust_directions  direction,

  Watchdog_Interval           units

);

/*

 *  _Watchdog_Insert

 *

 *  DESCRIPTION:

 *

 *  This routine inserts THE_WATCHDOG into the HEADER watchdog chain

 *  for a time of UNITS.  The INSERT_MODE indicates whether

 *  THE_WATCHDOG is to be activated automatically or later, explicitly

 *  by the caller.

 *

 */

void _Watchdog_Insert (

  Chain_Control         *header,

  Watchdog_Control      *the_watchdog

);

/*

 *  _Watchdog_Tickle

 *

 *  DESCRIPTION:

 *

 *  This routine is invoked at appropriate intervals to update

 *  the HEADER watchdog chain.

 */

void _Watchdog_Tickle (

  Chain_Control *header

);

#ifndef __RTEMS_APPLICATION__

#include <rtems/score/watchdog.inl>

#endif

#ifdef __cplusplus

}

#endif

#endif

/* end of include file */