Signed-off-by: Shumin Qiu <shumin.qiu@intel.com> Reviewed-by: Liming Gao <liming.gao@intel.com> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14739 6f19259b-4bc3-4df7-8a09-765794883524
		
			
				
	
	
		
			167 lines
		
	
	
		
			4.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			167 lines
		
	
	
		
			4.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/** @file
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  Implementation of Timestamp Protocol using UEFI APIs.
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Copyright (c) 2013, Intel Corporation. All rights reserved.<BR>
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This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution.  The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include <Uefi.h>
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#include <Library/DebugLib.h>
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#include <Library/UefiDriverEntryPoint.h>
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#include <Library/UefiBootServicesTableLib.h>
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#include <Library/TimerLib.h>
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#include <Library/BaseMemoryLib.h>
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#include <Protocol/Timestamp.h>
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//
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// The StartValue in TimerLib
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//
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UINT64 mTimerLibStartValue = 0;
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//
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// The EndValue in TimerLib
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//
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UINT64 mTimerLibEndValue = 0;
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//
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// The properties of timestamp
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//
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EFI_TIMESTAMP_PROPERTIES mTimestampProperties = {
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  0,
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  0
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};
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/**
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  Retrieves the current value of a 64-bit free running timestamp counter.
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  The counter shall count up in proportion to the amount of time that has passed. The counter value
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  will always roll over to zero. The properties of the counter can be retrieved from GetProperties().
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  The caller should be prepared for the function to return the same value twice across successive calls.
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  The counter value will not go backwards other than when wrapping, as defined by EndValue in GetProperties().
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  The frequency of the returned timestamp counter value must remain constant. Power management operations that 
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  affect clocking must not change the returned counter frequency. The quantization of counter value updates may 
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  vary as long as the value reflecting time passed remains consistent.           
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  @retval The current value of the free running timestamp counter.
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**/
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UINT64
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EFIAPI
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TimestampDriverGetTimestamp (
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  VOID
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  )
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{
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  //
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  // The timestamp of Timestamp Protocol
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  //
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  UINT64  TimestampValue;
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  TimestampValue = 0;
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  //
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  // Get the timestamp
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  //
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  if (mTimerLibStartValue > mTimerLibEndValue) {
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    TimestampValue = mTimerLibStartValue - GetPerformanceCounter();
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  } else {
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    TimestampValue = GetPerformanceCounter() - mTimerLibStartValue;
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  }
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  return TimestampValue;
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}
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/**
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  Obtains timestamp counter properties including frequency and value limits.
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  @param[out]  Properties              The properties of the timestamp counter.
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  @retval      EFI_SUCCESS             The properties were successfully retrieved. 
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  @retval      EFI_DEVICE_ERROR        An error occurred trying to retrieve the properties of the timestamp 
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                                       counter subsystem. Properties is not pedated.                                
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  @retval      EFI_INVALID_PARAMETER   Properties is NULL.
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**/
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EFI_STATUS
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EFIAPI
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TimestampDriverGetProperties(
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  OUT   EFI_TIMESTAMP_PROPERTIES       *Properties
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  )
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{
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  if (Properties == NULL) {
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    return EFI_INVALID_PARAMETER;
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  }
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  //
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  // Get timestamp properties
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  //
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  CopyMem((VOID *) Properties, (VOID *) &mTimestampProperties, sizeof (mTimestampProperties));
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  return EFI_SUCCESS;
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}
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//
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// The Timestamp Protocol instance produced by this driver
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//
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EFI_TIMESTAMP_PROTOCOL  mTimestamp = {
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  TimestampDriverGetTimestamp,
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  TimestampDriverGetProperties
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};
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/**
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  Entry point of the Timestamp Protocol driver.
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  @param  ImageHandle   The image handle of this driver.
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  @param  SystemTable   The pointer of EFI_SYSTEM_TABLE.
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  @retval EFI_SUCCESS   Watchdog Timer Architectural Protocol successfully installed.
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**/
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EFI_STATUS
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EFIAPI
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TimestampDriverInitialize (
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  IN EFI_HANDLE        ImageHandle,
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  IN EFI_SYSTEM_TABLE  *SystemTable
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  )
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{
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  EFI_STATUS  Status;
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  EFI_HANDLE  TimestampHandle;
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  TimestampHandle = NULL;
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  //
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  // Get the start value, end value and frequency in Timerlib
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  //
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  mTimestampProperties.Frequency = GetPerformanceCounterProperties(&mTimerLibStartValue, &mTimerLibEndValue);
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  //
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  // Set the EndValue 
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  //
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  if (mTimerLibEndValue > mTimerLibStartValue) {
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    mTimestampProperties.EndValue = mTimerLibEndValue - mTimerLibStartValue;
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  } else {
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    mTimestampProperties.EndValue = mTimerLibStartValue - mTimerLibEndValue;
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  }
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  DEBUG ((EFI_D_INFO, "TimerFrequency:0x%lx, TimerLibStartTime:0x%lx, TimerLibEndtime:0x%lx\n", mTimestampProperties.Frequency, mTimerLibStartValue, mTimerLibEndValue));
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  //
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  // Install the Timestamp Protocol onto a new handle
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  //
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  Status = gBS->InstallMultipleProtocolInterfaces (
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                  &TimestampHandle,
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                  &gEfiTimestampProtocolGuid,
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                  &mTimestamp,
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                  NULL
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                  );
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  ASSERT_EFI_ERROR (Status);
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  return EFI_SUCCESS;
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}
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