timer.c

来自「EFI BIOS是Intel提出的下一代的BIOS标准。这里上传的Edk源代码是」· C语言 代码 · 共 605 行 · 第 1/2 页

  if (NotifyFunction != NULL && mTimerNotifyFunction != NULL) {
    return EFI_ALREADY_STARTED;
  }

  //
  // Use Critical Section to update the notification function that is
  // used from the timer interrupt thread.
  //
  gWinNt->EnterCriticalSection (&mNtCriticalSection);

  mTimerNotifyFunction = NotifyFunction;

  gWinNt->LeaveCriticalSection (&mNtCriticalSection);

  return EFI_SUCCESS;
}

EFI_STATUS
EFIAPI
WinNtTimerDriverSetTimerPeriod (
  IN EFI_TIMER_ARCH_PROTOCOL  *This,
  IN UINT64                   TimerPeriod
  )
/*++

Routine Description:

  This function adjusts the period of timer interrupts to the value specified 
  by TimerPeriod.  If the timer period is updated, then the selected timer 
  period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If 
  the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.  
  If an error occurs while attempting to update the timer period, then the 
  timer hardware will be put back in its state prior to this call, and 
  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt 
  is disabled.  This is not the same as disabling the CPU's interrupts.  
  Instead, it must either turn off the timer hardware, or it must adjust the 
  interrupt controller so that a CPU interrupt is not generated when the timer 
  interrupt fires. 

Arguments:

  This        - The EFI_TIMER_ARCH_PROTOCOL instance.

  TimerPeriod - The rate to program the timer interrupt in 100 nS units.  If 
                the timer hardware is not programmable, then EFI_UNSUPPORTED is 
                returned.  If the timer is programmable, then the timer period 
                will be rounded up to the nearest timer period that is supported 
                by the timer hardware.  If TimerPeriod is set to 0, then the 
                timer interrupts will be disabled.

Returns: 

  EFI_SUCCESS      - The timer period was changed.

  EFI_UNSUPPORTED  - The platform cannot change the period of the timer interrupt.

  EFI_DEVICE_ERROR - The timer period could not be changed due to a device error.

--*/
{

  //
  // If TimerPeriod is 0, then the timer thread should be canceled
  //
  if (TimerPeriod == 0) {
    //
    // Cancel the timer thread
    //
    gWinNt->EnterCriticalSection (&mNtCriticalSection);

    mCancelTimerThread = TRUE;

    gWinNt->LeaveCriticalSection (&mNtCriticalSection);

    //
    // Wait for the timer thread to exit
    //

    if (mMMTimerThreadID) {
      gWinNt->timeKillEvent (mMMTimerThreadID);
    }

    mMMTimerThreadID = 0;

    //
    // Update the timer period
    //
    gWinNt->EnterCriticalSection (&mNtCriticalSection);

    mTimerPeriod = TimerPeriod;

    gWinNt->LeaveCriticalSection (&mNtCriticalSection);

    //
    // NULL out the thread handle so it will be re-created if the timer is enabled again
    //

  } else if ((TimerPeriod > TIMER_MINIMUM_VALUE) && (TimerPeriod < TIMER_MAXIMUM_VALUE)) {
    //
    // If the TimerPeriod is valid, then create and/or adjust the period of the timer thread
    //
    gWinNt->EnterCriticalSection (&mNtCriticalSection);

    mTimerPeriod        = TimerPeriod;

    mCancelTimerThread  = FALSE;

    gWinNt->LeaveCriticalSection (&mNtCriticalSection);

    //
    //  Get the starting tick location if we are just starting the timer thread
    //
    mNtLastTick = gWinNt->GetTickCount ();

    if (mMMTimerThreadID) {
      gWinNt->timeKillEvent (mMMTimerThreadID);
    }

    mMMTimerThreadID  = 0;

    mMMTimerThreadID  = CreateNtTimer ();

  }

  return EFI_SUCCESS;
}

EFI_STATUS
EFIAPI
WinNtTimerDriverGetTimerPeriod (
  IN EFI_TIMER_ARCH_PROTOCOL            *This,
  OUT UINT64                            *TimerPeriod
  )
/*++

Routine Description:

  This function retrieves the period of timer interrupts in 100 ns units, 
  returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod 
  is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is 
  returned, then the timer is currently disabled.

Arguments:

  This        - The EFI_TIMER_ARCH_PROTOCOL instance.

  TimerPeriod - A pointer to the timer period to retrieve in 100 ns units.  If 
                0 is returned, then the timer is currently disabled.

Returns: 

  EFI_SUCCESS           - The timer period was returned in TimerPeriod.

  EFI_INVALID_PARAMETER - TimerPeriod is NULL.

--*/
{
  if (TimerPeriod == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  *TimerPeriod = mTimerPeriod;

  return EFI_SUCCESS;
}

EFI_STATUS
EFIAPI
WinNtTimerDriverGenerateSoftInterrupt (
  IN EFI_TIMER_ARCH_PROTOCOL  *This
  )
/*++

Routine Description:

  This function generates a soft timer interrupt. If the platform does not support soft 
  timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned. 
  If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler() 
  service, then a soft timer interrupt will be generated. If the timer interrupt is 
  enabled when this service is called, then the registered handler will be invoked. The 
  registered handler should not be able to distinguish a hardware-generated timer 
  interrupt from a software-generated timer interrupt.

Arguments:

  This  -  The EFI_TIMER_ARCH_PROTOCOL instance.

Returns: 

  EFI_SUCCESS       - The soft timer interrupt was generated.

  EFI_UNSUPPORTEDT  - The platform does not support the generation of soft timer interrupts.

--*/
{
  return EFI_UNSUPPORTED;
}

EFI_DRIVER_ENTRY_POINT (WinNtTimerDriverInitialize)

EFI_STATUS
EFIAPI
WinNtTimerDriverInitialize (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
/*++

Routine Description:

  Initialize the Timer Architectural Protocol driver

Arguments:

  ImageHandle - ImageHandle of the loaded driver

  SystemTable - Pointer to the System Table

Returns:

  EFI_SUCCESS           - Timer Architectural Protocol created

  EFI_OUT_OF_RESOURCES  - Not enough resources available to initialize driver.
  
  EFI_DEVICE_ERROR      - A device error occured attempting to initialize the driver.

--*/
{
  EFI_STATUS  Status;
  UINTN       Result;
  EFI_HANDLE  Handle;

  //
  // Initialize the EFI Driver Library
  //
  EfiInitializeDriverLib (ImageHandle, SystemTable);
  EfiInitializeWinNtDriverLib (ImageHandle, SystemTable);

  //
  // Make sure the Timer Architectural Protocol is not already installed in the system
  //
  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);

  //
  // Get the CPU Architectural Protocol instance
  //
  Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, &mCpu);
  ASSERT_EFI_ERROR (Status);

  //
  //  Get our handle so the timer tick thread can suspend
  //
  Result = gWinNt->DuplicateHandle (
                    gWinNt->GetCurrentProcess (),
                    gWinNt->GetCurrentThread (),
                    gWinNt->GetCurrentProcess (),
                    &mNtMainThreadHandle,
                    0,
                    FALSE,
                    DUPLICATE_SAME_ACCESS
                    );
  if (Result == 0) {
    return EFI_DEVICE_ERROR;
  }

  //
  // Initialize Critical Section used to update variables shared between the main
  // thread and the timer interrupt thread.
  //
  gWinNt->InitializeCriticalSection (&mNtCriticalSection);

  //
  // Start the timer thread at the default timer period
  //
  Status = mTimer.SetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);
  if (EFI_ERROR (Status)) {
    gWinNt->DeleteCriticalSection (&mNtCriticalSection);
    return Status;
  }

  //
  // Install the Timer Architectural Protocol onto a new handle
  //
  Handle = NULL;
  Status = gBS->InstallProtocolInterface (
                  &Handle,
                  &gEfiTimerArchProtocolGuid,
                  EFI_NATIVE_INTERFACE,
                  &mTimer
                  );
  if (EFI_ERROR (Status)) {
    //
    // Cancel the timer
    //
    mTimer.SetTimerPeriod (&mTimer, 0);
    gWinNt->DeleteCriticalSection (&mNtCriticalSection);
    return Status;
  }

  return EFI_SUCCESS;
}