#include <sys/clock.h>
#include <sys/cc.h>
#include <sys/etimer.h>
#include <debug-uart.h>

#include <libopencm3/cm3/systick.h>

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

void sys_tick_handler(void) __attribute__ ((interrupt));

void
sys_tick_handler(void)
{
  current_clock++;
  if(etimer_pending() && etimer_next_expiration_time() <= current_clock) {
    etimer_request_poll();
    /* printf("%d,%d\n", clock_time(),etimer_next_expiration_time       ()); */
  }

  if(--second_countdown == 0) {
    current_seconds++;
    second_countdown = CLOCK_SECOND;
  }
}


void
clock_init()
{
  systick_set_clocksource(STK_CTRL_CLKSOURCE_AHB_DIV8);

  /*72mhz / 8 / 1000 */
  systick_set_reload(MCK / 8 / CLOCK_SECOND);

  systick_interrupt_enable();
  systick_counter_enable();
}

clock_time_t
clock_time(void)
{
  return current_clock;
}

unsigned long
clock_seconds(void)
{
  return current_seconds;
}

/* TODO: This code needs to be evaluated for the stm32f107 and
 * implemented
 */
#if 0
/* The inner loop takes 4 cycles. The outer 5+SPIN_COUNT*4. */

#define SPIN_TIME 2             /* us */
#define SPIN_COUNT (((MCK*SPIN_TIME/1000000)-5)/4)

#ifndef __MAKING_DEPS__

void
clock_delay(unsigned int t)
{
#ifdef __THUMBEL__
  asm
    volatile
    ("1: mov r1,%2\n2:\tsub r1,#1\n\tbne 2b\n\tsub %0,#1\n\tbne 1b\n":"=l"
     (t):"0"(t), "l"(SPIN_COUNT));
#else
#error Must be compiled in thumb mode
#endif
}
#endif
#endif /* __MAKING_DEPS__ */