/*++

Copyright (c) 2013-2017, ARM Ltd. All rights reserved.<BR>

This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution.  The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php

THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

--*/

#include "ArmGicDxe.h"

VOID
EFIAPI
IrqInterruptHandler (
  IN EFI_EXCEPTION_TYPE           InterruptType,
  IN EFI_SYSTEM_CONTEXT           SystemContext
  );

VOID
EFIAPI
ExitBootServicesEvent (
  IN EFI_EVENT  Event,
  IN VOID       *Context
  );

// Making this global saves a few bytes in image size
EFI_HANDLE  gHardwareInterruptHandle = NULL;

// Notifications
EFI_EVENT EfiExitBootServicesEvent      = (EFI_EVENT)NULL;

// Maximum Number of Interrupts
UINTN mGicNumInterrupts                 = 0;

HARDWARE_INTERRUPT_HANDLER  *gRegisteredInterruptHandlers = NULL;


/**
  Calculate GICD_ICFGRn base address and corresponding bit
  field Int_config[1] of the GIC distributor register.

  @param Source       Hardware source of the interrupt.
  @param RegAddress   Corresponding GICD_ICFGRn base address.
  @param Config1Bit   Bit number of F Int_config[1] bit in the register.

  @retval EFI_SUCCESS       Source interrupt supported.
  @retval EFI_UNSUPPORTED   Source interrupt is not supported.
**/
EFI_STATUS
GicGetDistributorIcfgBaseAndBit (
  IN HARDWARE_INTERRUPT_SOURCE             Source,
  OUT UINTN                               *RegAddress,
  OUT UINTN                               *Config1Bit
  )
{
  UINTN                  RegIndex;
  UINTN                  Field;

  if (Source >= mGicNumInterrupts) {
    ASSERT(Source < mGicNumInterrupts);
    return EFI_UNSUPPORTED;
  }

  RegIndex = Source / ARM_GIC_ICDICFR_F_STRIDE;  // NOTE: truncation is significant
  Field = Source % ARM_GIC_ICDICFR_F_STRIDE;
  *RegAddress = PcdGet64 (PcdGicDistributorBase)
                + ARM_GIC_ICDICFR
                + (ARM_GIC_ICDICFR_BYTES * RegIndex);
  *Config1Bit = ((Field * ARM_GIC_ICDICFR_F_WIDTH)
                 + ARM_GIC_ICDICFR_F_CONFIG1_BIT);

  return EFI_SUCCESS;
}



/**
  Register Handler for the specified interrupt source.

  @param This     Instance pointer for this protocol
  @param Source   Hardware source of the interrupt
  @param Handler  Callback for interrupt. NULL to unregister

  @retval EFI_SUCCESS Source was updated to support Handler.
  @retval EFI_DEVICE_ERROR  Hardware could not be programmed.

**/
EFI_STATUS
EFIAPI
RegisterInterruptSource (
  IN EFI_HARDWARE_INTERRUPT_PROTOCOL    *This,
  IN HARDWARE_INTERRUPT_SOURCE          Source,
  IN HARDWARE_INTERRUPT_HANDLER         Handler
  )
{
  if (Source >= mGicNumInterrupts) {
    ASSERT(FALSE);
    return EFI_UNSUPPORTED;
  }

  if ((Handler == NULL) && (gRegisteredInterruptHandlers[Source] == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  if ((Handler != NULL) && (gRegisteredInterruptHandlers[Source] != NULL)) {
    return EFI_ALREADY_STARTED;
  }

  gRegisteredInterruptHandlers[Source] = Handler;

  // If the interrupt handler is unregistered then disable the interrupt
  if (NULL == Handler){
    return This->DisableInterruptSource (This, Source);
  } else {
    return This->EnableInterruptSource (This, Source);
  }
}

STATIC VOID *mCpuArchProtocolNotifyEventRegistration;

STATIC
VOID
EFIAPI
CpuArchEventProtocolNotify (
  IN  EFI_EVENT       Event,
  IN  VOID            *Context
  )
{
  EFI_CPU_ARCH_PROTOCOL   *Cpu;
  EFI_STATUS              Status;

  // Get the CPU protocol that this driver requires.
  Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **)&Cpu);
  if (EFI_ERROR (Status)) {
    return;
  }

  // Unregister the default exception handler.
  Status = Cpu->RegisterInterruptHandler (Cpu, ARM_ARCH_EXCEPTION_IRQ, NULL);
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "%a: Cpu->RegisterInterruptHandler() - %r\n",
      __FUNCTION__, Status));
    return;
  }

  // Register to receive interrupts
  Status = Cpu->RegisterInterruptHandler (Cpu, ARM_ARCH_EXCEPTION_IRQ,
                  Context);
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "%a: Cpu->RegisterInterruptHandler() - %r\n",
      __FUNCTION__, Status));
  }

  gBS->CloseEvent (Event);
}

EFI_STATUS
InstallAndRegisterInterruptService (
  IN EFI_HARDWARE_INTERRUPT_PROTOCOL   *InterruptProtocol,
  IN EFI_HARDWARE_INTERRUPT2_PROTOCOL  *Interrupt2Protocol,
  IN EFI_CPU_INTERRUPT_HANDLER          InterruptHandler,
  IN EFI_EVENT_NOTIFY                   ExitBootServicesEvent
  )
{
  EFI_STATUS               Status;
  CONST UINTN              RihArraySize =
    (sizeof(HARDWARE_INTERRUPT_HANDLER) * mGicNumInterrupts);

  // Initialize the array for the Interrupt Handlers
  gRegisteredInterruptHandlers = AllocateZeroPool (RihArraySize);
  if (gRegisteredInterruptHandlers == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  Status = gBS->InstallMultipleProtocolInterfaces (
                  &gHardwareInterruptHandle,
                  &gHardwareInterruptProtocolGuid,
                  InterruptProtocol,
                  &gHardwareInterrupt2ProtocolGuid,
                  Interrupt2Protocol,
                  NULL
                  );
  if (EFI_ERROR (Status)) {
    return Status;
  }

  //
  // Install the interrupt handler as soon as the CPU arch protocol appears.
  //
  EfiCreateProtocolNotifyEvent (
    &gEfiCpuArchProtocolGuid,
    TPL_CALLBACK,
    CpuArchEventProtocolNotify,
    InterruptHandler,
    &mCpuArchProtocolNotifyEventRegistration);

  // Register for an ExitBootServicesEvent
  Status = gBS->CreateEvent (
                  EVT_SIGNAL_EXIT_BOOT_SERVICES,
                  TPL_NOTIFY,
                  ExitBootServicesEvent,
                  NULL,
                  &EfiExitBootServicesEvent
                  );

  return Status;
}