/* testpmt
 *
 * compares the current clock against the acpi_pm hardware timer,
 * and reports the error in ppm (parts in 1000000).
 * When clocksource=acpi_pm, and ntpd is not started, then
 * the output of this program should approach 0.000
 *
 *
 * compile with  gcc -O2 -o testpmt testpmt.c
 *
 * Kasper Pedersen <kkp2010@kasperkp.dk>
 *
 */

#include <stdio.h>
#include <sys/io.h>
#include <sys/time.h>
#define TPORT 0x808  FIXME: grep dmesg for PM-Timer and put the address here
int main(void)
{
	unsigned a,b;
	struct timeval tv;
	double t,t0,tik0;
	unsigned long long tik,basetik;

	basetik=b=tik0=0;
	ioperm(TPORT,4,1);
	for (;;) {
		a=inl(TPORT) & 0xffffff;
		gettimeofday(&tv,NULL);
		if (a<b) basetik+=0x1000000;
		b=a;
		tik=basetik+a;
		t=tv.tv_sec+0.000001*tv.tv_usec;
		if (!tik0) { 
			tik0=tik;
			t0=t;
		} else {
			t-=t0;
			tik-=tik0;
			printf("%f\n",((tik/t/3579545.0)-1.0)*1.0E6);
		}
		usleep(200000);
	}
}