30781febe2
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1909 Cc: Ray Ni <ray.ni@intel.com> Cc: Star Zeng <star.zeng@intel.com> Cc: Eric Dong <eric.dong@intel.com> Cc: Amy Chan <amy.chan@intel.com> Cc: Rangasai V Chaganty <rangasai.v.chaganty@intel.com> Signed-off-by: Donald Kuo <donald.kuo@intel.com> Reviewed-by: Eric Dong <eric.dong@intel.com>
42 lines
987 B
C
42 lines
987 B
C
/** @file
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CPUID Leaf 0x15 for Core Crystal Clock frequency instance as Base Timer Library.
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Copyright (c) 2019 Intel Corporation. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include <Base.h>
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#include <Library/TimerLib.h>
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#include <Library/BaseLib.h>
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/**
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CPUID Leaf 0x15 for Core Crystal Clock Frequency.
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The TSC counting frequency is determined by using CPUID leaf 0x15. Frequency in MHz = Core XTAL frequency * EBX/EAX.
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In newer flavors of the CPU, core xtal frequency is returned in ECX or 0 if not supported.
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@return The number of TSC counts per second.
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**/
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UINT64
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CpuidCoreClockCalculateTscFrequency (
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VOID
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);
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/**
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Internal function to retrieves the 64-bit frequency in Hz.
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Internal function to retrieves the 64-bit frequency in Hz.
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@return The frequency in Hz.
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**/
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UINT64
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InternalGetPerformanceCounterFrequency (
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VOID
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)
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{
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return CpuidCoreClockCalculateTscFrequency ();
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}
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