/****************************************************************************
 * sched/wdog/wdog.h
 *
 *   Copyright (C) 2007, 2009, 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 __SCHED_WDOG_WDOG_H
#define __SCHED_WDOG_WDOG_H

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <stdint.h>
#include <stdbool.h>

#include <nuttx/compiler.h>
#include <nuttx/clock.h>
#include <nuttx/wdog.h>

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Name: wd_elapse
 *
 * Description:
 *   This function is used to get time-elapse from last time wd_timer() be
 *   called. In case of CONFIG_SCHED_TICKLESS configured, wd_timer() may
 *   take lots of ticks, during this time, wd_start()/wd_cancel() may
 *   called, so we need wd_elapse() to correct the delay/lag.
 *
 ****************************************************************************/

#ifdef CONFIG_SCHED_TICKLESS
#  define wd_elapse() (clock_systimer() - g_wdtickbase)
#else
#  define wd_elapse() (0)
#endif

/****************************************************************************
 * Public Data
 ****************************************************************************/

#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif

/* The g_wdfreelist data structure is a singly linked list of watchdogs
 * available to the system for delayed function use.
 */

extern sq_queue_t g_wdfreelist;

/* The g_wdactivelist data structure is a singly linked list ordered by
 * watchdog expiration time. When watchdog timers expire,the functions on
 * this linked list are removed and the function is called.
 */

extern sq_queue_t g_wdactivelist;

/* This is the number of free, pre-allocated watchdog structures in the
 * g_wdfreelist.  This value is used to enforce a reserve for interrupt
 * handlers.
 */

extern uint16_t g_wdnfree;

/* This is wdog tickbase, for wd_gettime() may called many times
 * between 2 times of wd_timer(), we use it to update wd_gettime().
 */

#ifdef CONFIG_SCHED_TICKLESS
extern clock_t g_wdtickbase;
#endif

/****************************************************************************
 * Public Function Prototypes
 ****************************************************************************/

/****************************************************************************
 * Name: wd_initialize
 *
 * Description:
 * This function initializes the watchdog data structures
 *
 * Input Parameters:
 *   None
 *
 * Returned Value:
 *   None
 *
 * Assumptions:
 *   This function must be called early in the initialization sequence
 *   before the timer interrupt is attached and before any watchdog
 *   services are used.
 *
 ****************************************************************************/

void weak_function wd_initialize(void);

/****************************************************************************
 * Name: wd_timer
 *
 * Description:
 *   This function is called from the timer interrupt handler to determine
 *   if it is time to execute a watchdog function.  If so, the watchdog
 *   function will be executed in the context of the timer interrupt
 *   handler.
 *
 * Input Parameters:
 *   ticks - If CONFIG_SCHED_TICKLESS is defined then the number of ticks
 *     in the interval that just expired is provided.  Otherwise,
 *     this function is called on each timer interrupt and a value of one
 *     is implicit.
 *
 * Returned Value:
 *   If CONFIG_SCHED_TICKLESS is defined then the number of ticks for the
 *   next delay is provided (zero if no delay).  Otherwise, this function
 *   has no returned value.
 *
 * Assumptions:
 *   Called from interrupt handler logic with interrupts disabled.
 *
 ****************************************************************************/

#ifdef CONFIG_SCHED_TICKLESS
unsigned int wd_timer(int ticks);
#else
void wd_timer(void);
#endif

/****************************************************************************
 * Name: wd_recover
 *
 * Description:
 *   This function is called from nxtask_recover() when a task is deleted via
 *   task_delete() or via pthread_cancel(). It checks if the deleted task
 *   is waiting for a timed event and if so cancels the timeout
 *
 * Input Parameters:
 *   tcb - The TCB of the terminated task or thread
 *
 * Returned Value:
 *   None.
 *
 * Assumptions:
 *   This function is called from task deletion logic in a safe context.
 *
 ****************************************************************************/

struct tcb_s;
void wd_recover(FAR struct tcb_s *tcb);

#undef EXTERN
#ifdef __cplusplus
}
#endif

#endif /* __SCHED_WDOG_WDOG_H */