nuttx/sched/wdog/wd_gettime.c

/****************************************************************************
 * sched/wdog/wd_gettime.c
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

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

#include <nuttx/config.h>

#include <nuttx/wdog.h>
#include <nuttx/irq.h>

#include "wdog/wdog.h"

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: wd_gettime
 *
 * Description:
 *   This function returns the time remaining before the specified watchdog
 *   timer expires.
 *
 * Input Parameters:
 *   wdog - watchdog ID
 *
 * Returned Value:
 *   The time in system ticks remaining until the watchdog time expires.
 *   Zero means either that wdog is not valid or that the wdog has already
 *   expired.
 *
 ****************************************************************************/

sclock_t wd_gettime(FAR struct wdog_s *wdog)
{
  irqstate_t flags;

  /* Verify the wdog */

  flags = enter_critical_section();
  if (wdog != NULL && WDOG_ISACTIVE(wdog))
    {
      /* Traverse the watchdog list accumulating lag times until we find the
       * wdog that we are looking for
       */

      FAR struct wdog_s *curr;
      sclock_t delay = 0;

      for (curr = (FAR struct wdog_s *)g_wdactivelist.head;
           curr != NULL;
           curr = curr->next)
        {
          delay += curr->lag;
          if (curr == wdog)
            {
              delay -= wd_elapse();
              leave_critical_section(flags);
              return delay;
            }
        }
    }

  leave_critical_section(flags);
  return 0;
}