/** @file
  Xen ARM ACPI Platform Driver using Xen ARM multiboot protocol

  Copyright (C) 2016, Linaro Ltd. All rights reserved.

  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 <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiDriverEntryPoint.h>

#include <Protocol/AcpiTable.h>
#include <Protocol/FdtClient.h>

#include <IndustryStandard/Acpi.h>

/**
  Get the address of Xen ACPI Root System Description Pointer (RSDP)
  structure.

  @param  RsdpStructurePtr   Return pointer to RSDP structure

  @return EFI_SUCCESS        Find Xen RSDP structure successfully.
  @return EFI_NOT_FOUND      Don't find Xen RSDP structure.
  @return EFI_ABORTED        Find Xen RSDP structure, but it's not integrated.

**/
STATIC
EFI_STATUS
EFIAPI
GetXenArmAcpiRsdp (
  OUT   EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER   **RsdpPtr
  )
{
  EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER   *RsdpStructurePtr;
  EFI_STATUS                                     Status;
  FDT_CLIENT_PROTOCOL                            *FdtClient;
  CONST UINT64                                   *Reg;
  UINT32                                         RegElemSize, RegSize;
  UINT64                                         RegBase;
  UINT8                                          Sum;

  RsdpStructurePtr = NULL;
  FdtClient = NULL;
  //
  // Get the RSDP structure address from DeviceTree
  //
  Status = gBS->LocateProtocol (&gFdtClientProtocolGuid, NULL,
                  (VOID **)&FdtClient);
  ASSERT_EFI_ERROR (Status);

  Status = FdtClient->FindCompatibleNodeReg (FdtClient, "xen,guest-acpi",
                        (CONST VOID **)&Reg, &RegElemSize, &RegSize);
  if (EFI_ERROR (Status)) {
    DEBUG ((EFI_D_WARN, "%a: No 'xen,guest-acpi' compatible DT node found\n",
      __FUNCTION__));
    return EFI_NOT_FOUND;
  }

  ASSERT (RegSize == 2 * sizeof (UINT64));

  RegBase = SwapBytes64(Reg[0]);
  RsdpStructurePtr = (EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER *)RegBase;

  if (RsdpStructurePtr && RsdpStructurePtr->Revision >= 2) {
    Sum = CalculateSum8 ((CONST UINT8 *)RsdpStructurePtr,
            sizeof (EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER));
    if (Sum != 0) {
      return EFI_ABORTED;
    }
  }

  *RsdpPtr = RsdpStructurePtr;
  return EFI_SUCCESS;
}

/**
  Get Xen Acpi tables from the RSDP structure. And installs Xen ACPI tables
  into the RSDT/XSDT using InstallAcpiTable. Some signature of the installed
  ACPI tables are: FACP, APIC, GTDT, DSDT.

  @param  AcpiProtocol           Protocol instance pointer.

  @return EFI_SUCCESS            The table was successfully inserted.
  @return EFI_INVALID_PARAMETER  Either AcpiTableBuffer is NULL, TableHandle is
                                 NULL, or AcpiTableBufferSize and the size
                                 field embedded in the ACPI table pointed to
                                 by AcpiTableBuffer are not in sync.
  @return EFI_OUT_OF_RESOURCES   Insufficient resources exist to complete the request.

**/
STATIC
EFI_STATUS
EFIAPI
InstallXenArmTables (
  IN   EFI_ACPI_TABLE_PROTOCOL       *AcpiProtocol
  )
{
  EFI_STATUS                                       Status;
  UINTN                                            TableHandle;
  VOID                                             *CurrentTableEntry;
  UINTN                                            CurrentTablePointer;
  EFI_ACPI_DESCRIPTION_HEADER                      *CurrentTable;
  UINTN                                            Index;
  UINTN                                            NumberOfTableEntries;
  EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER     *XenAcpiRsdpStructurePtr;
  EFI_ACPI_DESCRIPTION_HEADER                      *Xsdt;
  EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE        *FadtTable;
  EFI_ACPI_DESCRIPTION_HEADER                      *DsdtTable;

  XenAcpiRsdpStructurePtr = NULL;
  FadtTable   = NULL;
  DsdtTable   = NULL;
  TableHandle = 0;
  NumberOfTableEntries = 0;

  //
  // Try to find Xen ARM ACPI tables
  //
  Status = GetXenArmAcpiRsdp (&XenAcpiRsdpStructurePtr);
  if (EFI_ERROR (Status)) {
    DEBUG ((EFI_D_INFO, "%a: No RSDP table found\n", __FUNCTION__));
    return Status;
  }

  //
  // If XSDT table is find, just install its tables.
  //
  if (XenAcpiRsdpStructurePtr->XsdtAddress) {
    //
    // Retrieve the addresses of XSDT and
    // calculate the number of its table entries.
    //
    Xsdt = (EFI_ACPI_DESCRIPTION_HEADER *) (UINTN)
             XenAcpiRsdpStructurePtr->XsdtAddress;
    NumberOfTableEntries = (Xsdt->Length -
                             sizeof (EFI_ACPI_DESCRIPTION_HEADER)) /
                             sizeof (UINT64);
    //
    // Install ACPI tables found in XSDT.
    //
    for (Index = 0; Index < NumberOfTableEntries; Index++) {
      //
      // Get the table entry from XSDT
      //
      CurrentTableEntry = (VOID *) ((UINT8 *) Xsdt +
                            sizeof (EFI_ACPI_DESCRIPTION_HEADER) +
                            Index * sizeof (UINT64));
      CurrentTablePointer = (UINTN) *(UINT64 *)CurrentTableEntry;
      CurrentTable = (EFI_ACPI_DESCRIPTION_HEADER *) CurrentTablePointer;

      //
      // Install the XSDT tables
      //
      Status = AcpiProtocol->InstallAcpiTable (
                 AcpiProtocol,
                 CurrentTable,
                 CurrentTable->Length,
                 &TableHandle
                 );

      if (EFI_ERROR (Status)) {
        return Status;
      }

      //
      // Get the FACS and DSDT table address from the table FADT
      //
      if (!AsciiStrnCmp ((CHAR8 *) &CurrentTable->Signature, "FACP", 4)) {
        FadtTable = (EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE *)
                      (UINTN) CurrentTablePointer;
        DsdtTable  = (EFI_ACPI_DESCRIPTION_HEADER *) (UINTN) FadtTable->Dsdt;
      }
    }
  }

  //
  // Install DSDT table.
  //
  Status = AcpiProtocol->InstallAcpiTable (
             AcpiProtocol,
             DsdtTable,
             DsdtTable->Length,
             &TableHandle
             );
  if (EFI_ERROR (Status)) {
    return Status;
  }

  return EFI_SUCCESS;
}

STATIC
EFI_ACPI_TABLE_PROTOCOL *
FindAcpiTableProtocol (
  VOID
  )
{
  EFI_STATUS              Status;
  EFI_ACPI_TABLE_PROTOCOL *AcpiTable;

  AcpiTable = NULL;
  Status = gBS->LocateProtocol (
                  &gEfiAcpiTableProtocolGuid,
                  NULL,
                  (VOID**)&AcpiTable
                  );
  ASSERT_EFI_ERROR (Status);
  return AcpiTable;
}

/**
  Entrypoint of Xen ARM Acpi Platform driver.

  @param  ImageHandle
  @param  SystemTable

  @return EFI_SUCCESS
  @return EFI_LOAD_ERROR
  @return EFI_OUT_OF_RESOURCES

**/

EFI_STATUS
EFIAPI
XenAcpiPlatformEntryPoint (
  IN EFI_HANDLE         ImageHandle,
  IN EFI_SYSTEM_TABLE   *SystemTable
  )
{
  EFI_STATUS                         Status;

  Status = InstallXenArmTables (FindAcpiTableProtocol ());
  return Status;
}