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/** @file
CPUID Leaf 0x15 for Core Crystal Clock frequency instance as PEI Timer Library.
Copyright (c) 2019 Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <PiPei.h>
#include <Library/TimerLib.h>
#include <Library/BaseLib.h>
#include <Library/HobLib.h>
#include <Library/DebugLib.h>
extern GUID mCpuCrystalFrequencyHobGuid;
/**
CPUID Leaf 0x15 for Core Crystal Clock Frequency.
The TSC counting frequency is determined by using CPUID leaf 0x15. Frequency in MHz = Core XTAL frequency * EBX/EAX.
In newer flavors of the CPU, core xtal frequency is returned in ECX or 0 if not supported.
@return The number of TSC counts per second.
**/
UINT64
CpuidCoreClockCalculateTscFrequency (
VOID
);
/**
Internal function to retrieves the 64-bit frequency in Hz.
Internal function to retrieves the 64-bit frequency in Hz.
@return The frequency in Hz.
**/
UINT64
InternalGetPerformanceCounterFrequency (
VOID
)
{
UINT64 *CpuCrystalCounterFrequency;
EFI_HOB_GUID_TYPE *GuidHob;
CpuCrystalCounterFrequency = NULL;
GuidHob = GetFirstGuidHob (&mCpuCrystalFrequencyHobGuid);
if (GuidHob == NULL) {
CpuCrystalCounterFrequency = (UINT64*)BuildGuidHob(&mCpuCrystalFrequencyHobGuid, sizeof (*CpuCrystalCounterFrequency));
ASSERT (CpuCrystalCounterFrequency != NULL);
*CpuCrystalCounterFrequency = CpuidCoreClockCalculateTscFrequency ();
} else {
CpuCrystalCounterFrequency = (UINT64*)GET_GUID_HOB_DATA (GuidHob);
}
return *CpuCrystalCounterFrequency;
}
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