src/soc/intel/baytrail/tsc_freq.c

/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2013 Google Inc.
 *
 * 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; version 2 of the License.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <stdint.h>
#include <cpu/x86/msr.h>
#include <cpu/x86/tsc.h>
#include <baytrail/msr.h>

#define BCLK 100 /* 100 MHz */
unsigned long tsc_freq_mhz(void)
{
	msr_t platform_info;

	platform_info = rdmsr(MSR_PLATFORM_INFO);
	return BCLK * ((platform_info.lo >> 8) & 0xff);
}