time.c

Intel PXA270的bootloader程序,在linux环境下运行的.

#include <hardware.h>
#include <time.h>

static unsigned long msecond_boundary;
static int udelay_init(void);

bool time_init(void){
	udelay_init();
	RCNR = 0;
	OSCR = 0;
	return true;
}

time_t time(time_t *t){
	*t = RCNR;		// 1 Hz
	return *t;
}

clock_t clock(void){
	return OSCR;	// 3.6864 MHz
}

/*
 * 100000 : a / 3686400 s = x : 1 / 1000 s
 * x = 3686400 * 100000 / (1000 * a)
 * x = 368640000 / a
 */
static int udelay_init(void){
	unsigned long i, diff;

	OSCR = 0;
	for (i=0; i < 100000; i++);
	diff = OSCR;
	msecond_boundary = 368640000 / diff;
	//printf("udelay : msecond_boundary : %d [0x%08lx]\n", msecond_boundary, msecond_boundary);
	return 0;
}

void udelay(unsigned long usecs){
	unsigned long i;
	for (i=0; i < msecond_boundary * usecs / 1000; i++);
	return;
}

void mdelay(unsigned long msecs){
	while (msecs-- > 0)
		udelay(1000);
	return;
}