coreboot-kgpe-d16/src/soc/intel/apollolake/tsc_freq.c

/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2015 Intel Corp.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <cpu/x86/msr.h>
#include <cpu/x86/tsc.h>
#include <soc/cpu.h>

unsigned long tsc_freq_mhz(void)
{
    msr_t msr = rdmsr(MSR_PLATFORM_INFO);
    return (BASE_CLOCK_MHZ * ((msr.lo >> 8) & 0xff));
}