MdeModulePkg/Universal/TimestampDxe/TimestampDxe.c

   1 /** @file
   2   Implementation of Timestamp Protocol using UEFI APIs.
   3
   4 Copyright (c) 2013, Intel Corporation. All rights reserved.<BR>
   5 This program and the accompanying materials
   6 are licensed and made available under the terms and conditions of the BSD License
   7 which accompanies this distribution.  The full text of the license may be found at
   8 http://opensource.org/licenses/bsd-license.php
   9
  10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include <Uefi.h>
  16 #include <Library/DebugLib.h>
  17 #include <Library/UefiDriverEntryPoint.h>
  18 #include <Library/UefiBootServicesTableLib.h>
  19 #include <Library/TimerLib.h>
  20 #include <Library/BaseMemoryLib.h>
  21 #include <Protocol/Timestamp.h>
  22
  23 //
  24 // The StartValue in TimerLib
  25 //
  26 UINT64 mTimerLibStartValue = 0;
  27
  28 //
  29 // The EndValue in TimerLib
  30 //
  31 UINT64 mTimerLibEndValue = 0;
  32
  33 //
  34 // The properties of timestamp
  35 //
  36 EFI_TIMESTAMP_PROPERTIES mTimestampProperties = {
  37   0,
  38   0
  39 };
  40
  41 /**
  42   Retrieves the current value of a 64-bit free running timestamp counter.
  43
  44   The counter shall count up in proportion to the amount of time that has passed. The counter value
  45   will always roll over to zero. The properties of the counter can be retrieved from GetProperties().
  46   The caller should be prepared for the function to return the same value twice across successive calls.
  47   The counter value will not go backwards other than when wrapping, as defined by EndValue in GetProperties().
  48   The frequency of the returned timestamp counter value must remain constant. Power management operations that
  49   affect clocking must not change the returned counter frequency. The quantization of counter value updates may
  50   vary as long as the value reflecting time passed remains consistent.
  51
  52   @retval The current value of the free running timestamp counter.
  53
  54 **/
  55 UINT64
  56 EFIAPI
  57 TimestampDriverGetTimestamp (
  58   VOID
  59   )
  60 {
  61   //
  62   // The timestamp of Timestamp Protocol
  63   //
  64   UINT64  TimestampValue;
  65   TimestampValue = 0;
  66
  67   //
  68   // Get the timestamp
  69   //
  70   if (mTimerLibStartValue > mTimerLibEndValue) {
  71     TimestampValue = mTimerLibStartValue - GetPerformanceCounter();
  72   } else {
  73     TimestampValue = GetPerformanceCounter() - mTimerLibStartValue;
  74   }
  75
  76   return TimestampValue;
  77 }
  78
  79 /**
  80   Obtains timestamp counter properties including frequency and value limits.
  81
  82   @param[out]  Properties              The properties of the timestamp counter.
  83
  84   @retval      EFI_SUCCESS             The properties were successfully retrieved.
  85   @retval      EFI_DEVICE_ERROR        An error occurred trying to retrieve the properties of the timestamp
  86                                        counter subsystem. Properties is not pedated.
  87   @retval      EFI_INVALID_PARAMETER   Properties is NULL.
  88
  89 **/
  90 EFI_STATUS
  91 EFIAPI
  92 TimestampDriverGetProperties(
  93   OUT   EFI_TIMESTAMP_PROPERTIES       *Properties
  94   )
  95 {
  96   if (Properties == NULL) {
  97     return EFI_INVALID_PARAMETER;
  98   }
  99
 100   //
 101   // Get timestamp properties
 102   //
 103   CopyMem((VOID *) Properties, (VOID *) &mTimestampProperties, sizeof (mTimestampProperties));
 104
 105   return EFI_SUCCESS;
 106 }
 107
 108 //
 109 // The Timestamp Protocol instance produced by this driver
 110 //
 111 EFI_TIMESTAMP_PROTOCOL  mTimestamp = {
 112   TimestampDriverGetTimestamp,
 113   TimestampDriverGetProperties
 114 };
 115
 116 /**
 117   Entry point of the Timestamp Protocol driver.
 118
 119   @param  ImageHandle   The image handle of this driver.
 120   @param  SystemTable   The pointer of EFI_SYSTEM_TABLE.
 121
 122   @retval EFI_SUCCESS   Watchdog Timer Architectural Protocol successfully installed.
 123
 124 **/
 125 EFI_STATUS
 126 EFIAPI
 127 TimestampDriverInitialize (
 128   IN EFI_HANDLE        ImageHandle,
 129   IN EFI_SYSTEM_TABLE  *SystemTable
 130   )
 131 {
 132   EFI_STATUS  Status;
 133
 134   EFI_HANDLE  TimestampHandle;
 135   TimestampHandle = NULL;
 136
 137   //
 138   // Get the start value, end value and frequency in Timerlib
 139   //
 140   mTimestampProperties.Frequency = GetPerformanceCounterProperties(&mTimerLibStartValue, &mTimerLibEndValue);
 141
 142   //
 143   // Set the EndValue
 144   //
 145   if (mTimerLibEndValue > mTimerLibStartValue) {
 146     mTimestampProperties.EndValue = mTimerLibEndValue - mTimerLibStartValue;
 147   } else {
 148     mTimestampProperties.EndValue = mTimerLibStartValue - mTimerLibEndValue;
 149   }
 150
 151   DEBUG ((EFI_D_INFO, "TimerFrequency:0x%lx, TimerLibStartTime:0x%lx, TimerLibEndtime:0x%lx\n", mTimestampProperties.Frequency, mTimerLibStartValue, mTimerLibEndValue));
 152
 153   //
 154   // Install the Timestamp Protocol onto a new handle
 155   //
 156   Status = gBS->InstallMultipleProtocolInterfaces (
 157                   &TimestampHandle,
 158                   &gEfiTimestampProtocolGuid,
 159                   &mTimestamp,
 160                   NULL
 161                   );
 162
 163   ASSERT_EFI_ERROR (Status);
 164
 165   return EFI_SUCCESS;
 166 }