WatchdogTimer.c

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#include "WatchdogTimer.h"
 
//
// Handle for the Watchdog Timer Architectural Protocol instance produced by this driver
//
EFI_HANDLE  mWatchdogTimerHandle = NULL;
 
//
// The Watchdog Timer Architectural Protocol instance produced by this driver
//
EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  mWatchdogTimer = {
  WatchdogTimerDriverRegisterHandler,
  WatchdogTimerDriverSetTimerPeriod,
  WatchdogTimerDriverGetTimerPeriod
};
 
//
// The watchdog timer period in 100 ns units
//
UINT64  mWatchdogTimerPeriod = 0;
 
//
// The notification function to call if the watchdig timer fires
//
EFI_WATCHDOG_TIMER_NOTIFY  mWatchdogTimerNotifyFunction = NULL;
 
//
// The one-shot timer event that is armed when the watchdog timer is enabled
//
EFI_EVENT  mWatchdogTimerEvent;
 
VOID
EFIAPI
WatchdogTimerDriverExpires (
  IN EFI_EVENT  Timer,
  IN VOID       *Context
  )
{
  REPORT_STATUS_CODE (EFI_ERROR_CODE | EFI_ERROR_MINOR, (EFI_COMPUTING_UNIT_HOST_PROCESSOR | EFI_CU_HP_EC_TIMER_EXPIRED));
 
  //
  // If a notification function has been registered, then call it
  //
  if (mWatchdogTimerNotifyFunction != NULL) {
    mWatchdogTimerNotifyFunction (mWatchdogTimerPeriod);
  }
 
  DEBUG ((DEBUG_ERROR, "Watchdog Timer resetting system\n"));
 
  //
  // Reset the platform
  //
  gRT->ResetSystem (EfiResetCold, EFI_TIMEOUT, 0, NULL);
}
 
EFI_STATUS
EFIAPI
WatchdogTimerDriverRegisterHandler (
  IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
  IN EFI_WATCHDOG_TIMER_NOTIFY         NotifyFunction
  )
{
  //
  // If NotifyFunction is NULL, and a handler was not previously registered,
  // return EFI_INVALID_PARAMETER.
  //
  if ((NotifyFunction == NULL) && (mWatchdogTimerNotifyFunction == NULL)) {
    return EFI_INVALID_PARAMETER;
  }
 
  //
  // If NotifyFunction is not NULL, and a handler is already registered,
  // return EFI_ALREADY_STARTED.
  //
  if ((NotifyFunction != NULL) && (mWatchdogTimerNotifyFunction != NULL)) {
    return EFI_ALREADY_STARTED;
  }
 
  mWatchdogTimerNotifyFunction = NotifyFunction;
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
EFIAPI
WatchdogTimerDriverSetTimerPeriod (
  IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
  IN UINT64                            TimerPeriod
  )
{
  mWatchdogTimerPeriod = TimerPeriod;
 
  return gBS->SetTimer (
                mWatchdogTimerEvent,
                (mWatchdogTimerPeriod == 0) ? TimerCancel : TimerRelative,
                mWatchdogTimerPeriod
                );
}
 
EFI_STATUS
EFIAPI
WatchdogTimerDriverGetTimerPeriod (
  IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
  IN UINT64                            *TimerPeriod
  )
{
  if (TimerPeriod == NULL) {
    return EFI_INVALID_PARAMETER;
  }
 
  *TimerPeriod = mWatchdogTimerPeriod;
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
EFIAPI
WatchdogTimerDriverInitialize (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS  Status;
 
  //
  // Make sure the Watchdog Timer Architectural Protocol has not been installed in the system yet.
  //
  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiWatchdogTimerArchProtocolGuid);
 
  //
  // Create the timer event to implement a simple watchdog timer
  //
  Status = gBS->CreateEvent (
                  EVT_TIMER | EVT_NOTIFY_SIGNAL,
                  TPL_NOTIFY,
                  WatchdogTimerDriverExpires,
                  NULL,
                  &mWatchdogTimerEvent
                  );
  ASSERT_EFI_ERROR (Status);
 
  //
  // Install the Watchdog Timer Arch Protocol onto a new handle
  //
  Status = gBS->InstallMultipleProtocolInterfaces (
                  &mWatchdogTimerHandle,
                  &gEfiWatchdogTimerArchProtocolGuid,
                  &mWatchdogTimer,
                  NULL
                  );
  ASSERT_EFI_ERROR (Status);
 
  return EFI_SUCCESS;
}