/**
 * Copyright (c) 2014, Analog Devices, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted (subject to the limitations in the
 * disclaimer below) 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 Analog Devices, Inc. nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE
 * GRANTED BY THIS LICENSE.  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.
 */
/**
 * \author Jim Paris <jim.paris@rigado.com>
 */

#include <aducrf101-contiki.h>
#include <sys/clock.h>
#include <sys/etimer.h>

static volatile clock_time_t current_clock = 0;
static volatile unsigned long current_seconds = 0;
static unsigned int second_countdown = CLOCK_SECOND;

void
SysTick_handler(void) __attribute__ ((interrupt));

void
SysTick_Handler(void)
{
  current_clock++;
  if(etimer_pending()) {
    etimer_request_poll();
  }
  if(--second_countdown == 0) {
    current_seconds++;
    second_countdown = CLOCK_SECOND;
  }
}
/*---------------------------------------------------------------------------*/
void
clock_init()
{
  SysTick_Config(F_CPU / CLOCK_SECOND);
}
/*---------------------------------------------------------------------------*/
clock_time_t
clock_time(void)
{
  return current_clock;
}
/*---------------------------------------------------------------------------*/
unsigned long
clock_seconds(void)
{
  return current_seconds;
}
/*---------------------------------------------------------------------------*/
void
clock_delay_usec(uint16_t usec)
{
  /* Delay by watching the SysTick value change. */
  int32_t remaining = (int32_t)usec * F_CPU / 1000000;
  int32_t old = SysTick->VAL;
  while(remaining > 0) {
    int32_t new = SysTick->VAL;
    if(new > old) { /* wraparound */
      old += SysTick->LOAD;
    }
    remaining -= (old - new);
    old = new;
  }
}