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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2015 Intel Corp.
* Copyright (C) 2017 Advanced Micro Devices
*
* 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/amd/msr.h>
#include <cpu/x86/tsc.h>
#include <console/console.h>
static unsigned long mhz;
unsigned long tsc_freq_mhz(void)
{
msr_t msr;
uint8_t cpufid;
uint8_t cpudid;
uint8_t high_state;
if (mhz)
return mhz;
high_state = rdmsr(PS_LIM_REG).lo & 0x7;
msr = rdmsr(PSTATE_0_MSR + high_state);
if (!(msr.hi & 0x80000000))
die("Unknown error: cannot determine P-state 0\n");
cpufid = (msr.lo & 0x3f);
cpudid = (msr.lo & 0x1c0) >> 6;
mhz = (100 * (cpufid + 0x10)) / (0x01 << cpudid);
return mhz;
}
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