#include <linux/config.h>
#include <asm/io.h>
 
static void mach_led(int position, int value)
{
   /* Do something here to switch the LED on or off depending on value */ 
}
 
#ifdef CONFIG_HEARTBEAT
 
#include <linux/sched.h>
 
/* acts like an actual heart beat -- ie thump-thump-pause... */ 
void heartbeat_saruman(void) {
   static unsigned cnt = 0, period = 0, dist = 0;
 
   if (cnt == 0 || cnt == dist)
      mach_led( -1, 1);
   else if (cnt == 7 || cnt == dist+7)
      mach_led( -1, 0);
 
   if (++cnt > period) {
      cnt = 0;
      /* The hyperbolic function below modifies the heartbeat period
       * length in dependency of the current (5min) load. It goes
       * through the points f(0)=126, f(1)=86, f(5)=51,
       * f(inf)->30. */
      period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
      dist = period / 4;
   }
}
#endif