PcAtChipsetPkg: Add PeiAcpiTimerLib to save Frequency in HOB

[mirror_edk2.git] / PcAtChipsetPkg / Library / AcpiTimerLib / DxeAcpiTimerLib.c

diff --git a/PcAtChipsetPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.c b/PcAtChipsetPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.c
index 6f5c07a4f0b4d6d9a156e885a5aa6e1d0a216ed3..67e18a13607fbf82f55741d612e0eb844bab276d 100644 (file)
--- a/PcAtChipsetPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.c
+++ b/PcAtChipsetPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.c
@@ -1,7 +1,7 @@
 /** @file\r
   ACPI Timer implements one instance of Timer Library.\r
 \r
-  Copyright (c) 2013 - 2014, Intel Corporation. All rights reserved.<BR>\r
+  Copyright (c) 2013 - 2016, Intel Corporation. All rights reserved.<BR>\r
   This program and the accompanying materials\r
   are licensed and made available under the terms and conditions of the BSD License\r
   which accompanies this distribution.  The full text of the license may be found at\r
@@ -12,9 +12,47 @@
 \r
 **/\r
 \r
-#include <Base.h>\r
+#include <PiDxe.h>\r
 #include <Library/TimerLib.h>\r
 #include <Library/BaseLib.h>\r
+#include <Library/HobLib.h>\r
+\r
+extern GUID mFrequencyHobGuid;\r
+\r
+/**\r
+  The constructor function enables ACPI IO space.\r
+\r
+  If ACPI I/O space not enabled, this function will enable it.\r
+  It will always return RETURN_SUCCESS.\r
+\r
+  @retval EFI_SUCCESS   The constructor always returns RETURN_SUCCESS.\r
+\r
+**/\r
+RETURN_STATUS\r
+EFIAPI\r
+AcpiTimerLibConstructor (\r
+  VOID\r
+  );\r
+\r
+/**\r
+  Calculate TSC frequency.\r
+\r
+  The TSC counting frequency is determined by comparing how far it counts\r
+  during a 101.4 us period as determined by the ACPI timer.\r
+  The ACPI timer is used because it counts at a known frequency.\r
+  The TSC is sampled, followed by waiting 363 counts of the ACPI timer,\r
+  or 101.4 us. The TSC is then sampled again. The difference multiplied by\r
+  9861 is the TSC frequency. There will be a small error because of the\r
+  overhead of reading the ACPI timer. An attempt is made to determine and\r
+  compensate for this error.\r
+\r
+  @return The number of TSC counts per second.\r
+\r
+**/\r
+UINT64\r
+InternalCalculateTscFrequency (\r
+  VOID\r
+  );\r
 \r
 //\r
 // Cached performance counter frequency\r
@@ -34,15 +72,41 @@ InternalGetPerformanceCounterFrequency (
   VOID\r
   ) \r
 {\r
-  BOOLEAN  InterruptState;\r
-  UINT64   Count;\r
-\r
-  if (mPerformanceCounterFrequency == 0) {\r
-    InterruptState = SaveAndDisableInterrupts ();\r
-    Count = GetPerformanceCounter ();\r
-    MicroSecondDelay (100);\r
-    mPerformanceCounterFrequency = MultU64x32 (GetPerformanceCounter () - Count, 10000);\r
-    SetInterruptState (InterruptState);\r
-  }\r
   return  mPerformanceCounterFrequency;\r
 }\r
+\r
+/**\r
+  The constructor function enables ACPI IO space, and caches PerformanceCounterFrequency. \r
+\r
+  @param  ImageHandle   The firmware allocated handle for the EFI image.\r
+  @param  SystemTable   A pointer to the EFI System Table.\r
+\r
+  @retval EFI_SUCCESS   The constructor always returns RETURN_SUCCESS.\r
+\r
+**/\r
+EFI_STATUS\r
+EFIAPI\r
+DxeAcpiTimerLibConstructor (\r
+  IN EFI_HANDLE        ImageHandle,\r
+  IN EFI_SYSTEM_TABLE  *SystemTable\r
+  )\r
+{\r
+  EFI_HOB_GUID_TYPE   *GuidHob;\r
+\r
+  //\r
+  // Enable ACPI IO space.\r
+  //\r
+  AcpiTimerLibConstructor ();\r
+\r
+  //\r
+  // Initialize PerformanceCounterFrequency\r
+  //\r
+  GuidHob = GetFirstGuidHob (&mFrequencyHobGuid);\r
+  if (GuidHob != NULL) {\r
+    mPerformanceCounterFrequency = *(UINT64*)GET_GUID_HOB_DATA (GuidHob);\r
+  } else {\r
+    mPerformanceCounterFrequency = InternalCalculateTscFrequency ();\r
+  }\r
+\r
+  return EFI_SUCCESS;\r
+}\r