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/* SPDX-License-Identifier: GPL-2.0-or-later */
/* This file is part of the coreboot project. */
#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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