/**
C Interrupt Handler called in the interrupt context when Source interrupt is active.
@param Source Source of the interrupt. Hardware routing off a specific platform defines
what source means.
@param SystemContext Pointer to system register context. Mostly used by debuggers and will
update the system context after the return from the interrupt if
modified. Don't change these values unless you know what you are doing
**/
VOID
EFIAPI
TimerInterruptHandler (
IN HARDWARE_INTERRUPT_SOURCE Source,
IN EFI_SYSTEM_CONTEXT SystemContext
)
{
EFI_TPL OriginalTPL;
//
// DXE core uses this callback for the EFI timer tick. The DXE core uses locks
// that raise to TPL_HIGH and then restore back to current level. Thus we need
// to make sure TPL level is set to TPL_HIGH while we are handling the timer tick.
//
OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
// Check if the timer interrupt is active
if ((ArmArchTimerGetTimerCtrlReg () ) & ARM_ARCH_TIMER_ISTATUS) {
// Signal end of interrupt early to help avoid losing subsequent ticks from long duration handlers
gInterrupt->EndOfInterrupt (gInterrupt, Source);
if (mTimerNotifyFunction) {
mTimerNotifyFunction (mTimerPeriod);
}
// Reload the Timer
TimerDriverSetTimerPeriod (&gTimer, FixedPcdGet32(PcdTimerPeriod));
}
// Enable timer interrupts
gInterrupt->EnableInterruptSource (gInterrupt, Source);
gBS->RestoreTPL (OriginalTPL);
}
/**
Initialize the state information for the Timer Architectural Protocol and
the Timer Debug support protocol that allows the debugger to break into a
running program.
@param ImageHandle of the loaded driver
@param SystemTable Pointer to the System Table
@retval EFI_SUCCESS Protocol registered
@retval EFI_OUT_OF_RESOURCES Cannot allocate protocol data structure
@retval EFI_DEVICE_ERROR Hardware problems
**/
EFI_STATUS
EFIAPI
TimerInitialize (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
EFI_HANDLE Handle = NULL;
EFI_STATUS Status;
UINTN TimerCtrlReg;
if (ArmIsArchTimerImplemented () == 0) {
DEBUG ((EFI_D_ERROR, "ARM Architectural Timer is not available in the CPU, hence cann't use this Driver \n"));
ASSERT (0);
}
// Find the interrupt controller protocol. ASSERT if not found.
Status = gBS->LocateProtocol (&gHardwareInterruptProtocolGuid, NULL, (VOID **)&gInterrupt);
ASSERT_EFI_ERROR (Status);
// Disable the timer
TimerCtrlReg = ArmArchTimerGetTimerCtrlReg ();
TimerCtrlReg |= ARM_ARCH_TIMER_IMASK;
TimerCtrlReg &= ~ARM_ARCH_TIMER_ENABLE;
ArmArchTimerSetTimerCtrlReg (TimerCtrlReg);
Status = TimerDriverSetTimerPeriod (&gTimer, 0);
ASSERT_EFI_ERROR (Status);
// Install secure and Non-secure interrupt handlers
// Note: Because it is not possible to determine the security state of the
// CPU dynamically, we just install interrupt handler for both sec and non-sec
// timer PPI
Status = gInterrupt->RegisterInterruptSource (gInterrupt, PcdGet32 (PcdArmArchTimerSecIntrNum), TimerInterruptHandler);
ASSERT_EFI_ERROR (Status);
Status = gInterrupt->RegisterInterruptSource (gInterrupt, PcdGet32 (PcdArmArchTimerIntrNum), TimerInterruptHandler);
ASSERT_EFI_ERROR (Status);
// Set up default timer
Status = TimerDriverSetTimerPeriod (&gTimer, FixedPcdGet32(PcdTimerPeriod)); // TIMER_DEFAULT_PERIOD
ASSERT_EFI_ERROR (Status);
// Install the Timer Architectural Protocol onto a new handle
Status = gBS->InstallMultipleProtocolInterfaces(
&Handle,
&gEfiTimerArchProtocolGuid, &gTimer,
NULL
);
ASSERT_EFI_ERROR(Status);
// Everything is ready, unmask and enable timer interrupts
TimerCtrlReg = ARM_ARCH_TIMER_ENABLE;
ArmArchTimerSetTimerCtrlReg (TimerCtrlReg);
// Register for an ExitBootServicesEvent
Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_NOTIFY, ExitBootServicesEvent, NULL, &EfiExitBootServicesEvent);
ASSERT_EFI_ERROR (Status);
return Status;
}