/************************************************************
 * wd_create.c
 *
 *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
 *
 * 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 Gregory Nutt 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.
 *
 ************************************************************/

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

#include <sys/types.h>
#include <wdog.h>
#include <queue.h>
#include <nuttx/arch.h>
#include "wd_internal.h"

/************************************************************
 * Definitions
 ************************************************************/

/************************************************************
 * Private Type Declarations
 ************************************************************/

/************************************************************
 * Global Variables
 ************************************************************/

/************************************************************
 * Private Variables
 ************************************************************/

/************************************************************
 * Private Functions
 ************************************************************/

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

/************************************************************
 * Function:  wd_create
 *
 * Description:  
 *   The wd_create function will create a watchdog by
 *   allocating it from the free list.
 *
 * Parameters:
 *   None
 *
 * Return Value:
 *   Pointer to watchdog (i.e., the watchdog ID), or NULL
 *   if insufficient watchdogs are available.
 *
 * Assumptions:
 *
 ************************************************************/

WDOG_ID wd_create (void)
{
  wdog_t    *wdog;
  irqstate_t saved_state;

  saved_state = irqsave();
  wdog = (wdog_t*)sq_remfirst(&g_wdfreelist);
  irqrestore(saved_state);

  /* Indicate that the watchdog is not actively timing */

  if (wdog)
    {
      wdog->next = NULL;
      wdog->active = FALSE;
    }
  return (WDOG_ID)wdog;
}