1 files changed, 85 insertions, 0 deletions
diff --git a/roms/edk2/UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.c b/roms/edk2/UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.c
new file mode 100644
index 000000000..269e5a3e8
--- /dev/null
+++ b/roms/edk2/UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.c
@@ -0,0 +1,85 @@
+/** @file
+  CPUID Leaf 0x15 for Core Crystal Clock frequency instance of Timer Library.
+
+  Copyright (c) 2019 Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <PiDxe.h>
+#include <Library/TimerLib.h>
+#include <Library/BaseLib.h>
+#include <Library/HobLib.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
+  );
+
+//
+// Cached CPU Crystal counter frequency
+//
+UINT64  mCpuCrystalCounterFrequency = 0;
+
+
+/**
+  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
+  )
+{
+  return mCpuCrystalCounterFrequency;
+}
+
+/**
+  The constructor function is to initialize CpuCrystalCounterFrequency.
+
+  @param  ImageHandle   The firmware allocated handle for the EFI image.
+  @param  SystemTable   A pointer to the EFI System Table.
+
+  @retval EFI_SUCCESS   The constructor always returns RETURN_SUCCESS.
+
+**/
+EFI_STATUS
+EFIAPI
+DxeCpuTimerLibConstructor (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  EFI_HOB_GUID_TYPE   *GuidHob;
+
+  //
+  // Initialize CpuCrystalCounterFrequency
+  //
+  GuidHob = GetFirstGuidHob (&mCpuCrystalFrequencyHobGuid);
+  if (GuidHob != NULL) {
+    mCpuCrystalCounterFrequency = *(UINT64*)GET_GUID_HOB_DATA (GuidHob);
+  } else {
+    mCpuCrystalCounterFrequency = CpuidCoreClockCalculateTscFrequency ();
+  }
+
+  if (mCpuCrystalCounterFrequency == 0) {
+    return EFI_UNSUPPORTED;
+  }
+
+  return EFI_SUCCESS;
+}
+