/*
   Copyright (c) 2002, 2004 Marek Michalkiewicz
   Copyright (c) 2005, 2006, 2007 Eric B. Weddington
   Copyright (c) 2015 Matthijs Kooijman
   All rights reserved.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions are met:

   * Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.

   * 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.

   * Neither the name of the copyright holders nor the names of
     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.

  This file provides a variant on the wdt_enable() macro (taken from
  avr/wdt.h) that can enable the watchdog timer interrupt, but not the
  timer itself.

  This file only provides the Atmega version, ideally avr-libc would
  provide a version for all supported devices. A request for this was filed at
  https://savannah.nongnu.org/bugs/?45420

  The name of the macro below is intentionally not wdt_enable_interrupt,
  to prevent conflicts later if avr-libc adds this macro as well.

  This macro uses inline assembly, since this is the only way to really
  guarantee the correct timed sequence needed to change the watchdog
  register. Using plain C with things in the right order will _usually_
  work, but sometimes the compiler gets smart and reorders some
  instructions or control flow, breaking things.
  */

#ifndef _AVR_WDT_INTERRUPT_H_
#define _AVR_WDT_INTERRUPT_H_

#include <avr/io.h>
#include <stdint.h>

#define enable_wdt_interrupt(value)   \
__asm__ __volatile__ (  \
    "in __tmp_reg__,__SREG__" "\n\t"    \
    "cli" "\n\t"    \
    "wdr" "\n\t"    \
    "sts %0,%1" "\n\t"  \
    "out __SREG__,__tmp_reg__" "\n\t"   \
    "sts %0,%2" "\n\t" \
    : /* no outputs */  \
    : "M" (_SFR_MEM_ADDR(_WD_CONTROL_REG)), \
    "r" (_BV(_WD_CHANGE_BIT) | _BV(WDE)), \
    "r" ((uint8_t) ((value & 0x08 ? _WD_PS3_MASK : 0x00) | \
        _BV(WDIE) | (value & 0x07)) ) \
    : "r0"  \
)

#endif // _AVR_WDT_INTERRUPT_H_