hpet.c

Go to the documentation of this file.

/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <arch/hpet.h>
#include <southbridge/intel/common/rcba.h>
#include <stdint.h>
 
#include "hpet.h"
 
#define HPTC            0x3404
 
#define HPET32(x) (*((volatile u32 *)(HPET_BASE_ADDRESS + (x))))
 
void enable_hpet(void)
{
        u32 reg32;
        reg32 = RCBA32(HPTC);
        reg32 &= ~0x03;
        reg32 |= (1 << 7);
        RCBA32(HPTC) = reg32;
        /* Read back for posted write to take effect */
        RCBA32(HPTC);
        HPET32(0x10) = HPET32(0x10) | 1;
}
 
void hpet_udelay(u32 delay)
{
        u32 start, finish, now;
 
        delay *= 15; /* now in usec */
 
        start = HPET32(0xf0);
        finish = start + delay;
        while (1) {
                now = HPET32(0xf0);
                if (finish > start) {
                        if (now >= finish)
                                break;
                } else {
                        if ((now < start) && (now >= finish))
                                break;
                }
        }
}