diff mbox series

[edk2,edk2-platforms,07/12] Hisilicon: add PciHostBridgeLib

Message ID 1521594198-52523-8-git-send-email-heyi.guo@linaro.org
State New
Headers show
Series Hisilicon/D0x: Switch to generic PciHostBridge | expand

Commit Message

gary guo March 21, 2018, 1:03 a.m. UTC
This is to prepare for switching to generic PciHostBridge, and
PciHostBridgeLib is needed by PciHostBridge driver.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Heyi Guo <heyi.guo@linaro.org>

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
---
 Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.inf |  51 ++++
 Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.c   | 304 ++++++++++++++++++++
 2 files changed, 355 insertions(+)

-- 
2.7.4

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Comments

Ard Biesheuvel March 30, 2018, 3:28 p.m. UTC | #1
On 21 March 2018 at 01:03, Heyi Guo <heyi.guo@linaro.org> wrote:
> This is to prepare for switching to generic PciHostBridge, and

> PciHostBridgeLib is needed by PciHostBridge driver.

>

> Contributed-under: TianoCore Contribution Agreement 1.1

> Signed-off-by: Heyi Guo <heyi.guo@linaro.org>

> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>

> Cc: Leif Lindholm <leif.lindholm@linaro.org>

> Cc: Michael D Kinney <michael.d.kinney@intel.com>

> ---

>  Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.inf |  51 ++++

>  Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.c   | 304 ++++++++++++++++++++

>  2 files changed, 355 insertions(+)

>

> diff --git a/Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.inf b/Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.inf

> new file mode 100644

> index 000000000000..dd451cff332c

> --- /dev/null

> +++ b/Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.inf

> @@ -0,0 +1,51 @@

> +## @file

> +#  PCI Host Bridge Library instance for Hisilicon D0x

> +#

> +#  Copyright (c) 2018, Hisilicon Limited. All rights reserved.<BR>

> +#  Copyright (c) 2017 - 2018, Linaro 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.

> +#

> +#

> +##

> +

> +[Defines]

> +  INF_VERSION                    = 0x0001000A

> +  BASE_NAME                      = PciHostBridgeLib

> +  FILE_GUID                      = e5c91e8a-0b2b-11e8-9533-286ed489ee9b

> +  MODULE_TYPE                    = DXE_DRIVER

> +  VERSION_STRING                 = 1.0

> +  LIBRARY_CLASS                  = PciHostBridgeLib|DXE_DRIVER

> +

> +#

> +# The following information is for reference only and not required by the build

> +# tools.

> +#

> +#  VALID_ARCHITECTURES           = AARCH64 ARM

> +#

> +

> +[Sources]

> +  PciHostBridgeLib.c

> +

> +[Packages]

> +  MdeModulePkg/MdeModulePkg.dec

> +  MdePkg/MdePkg.dec

> +  Silicon/Hisilicon/HisiPkg.dec

> +

> +[LibraryClasses]

> +  BaseLib

> +  BaseMemoryLib

> +  DebugLib

> +  DevicePathLib

> +  MemoryAllocationLib

> +  OemMiscLib

> +

> +[Pcd]

> +  gHisiTokenSpaceGuid.PcdPcieRootBridgeMask

> +  gHisiTokenSpaceGuid.PcdPcieRootBridgeMask2P

> diff --git a/Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.c b/Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.c

> new file mode 100644

> index 000000000000..6aff5cdd3d76

> --- /dev/null

> +++ b/Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.c

> @@ -0,0 +1,304 @@

> +/** @file

> +  PCI Host Bridge Library instance for Hisilicon D0x

> +

> +  Copyright (c) 2018, Hisilicon Limited. All rights reserved.<BR>

> +  Copyright (c) 2017 - 2018, Linaro 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 <PiDxe.h>

> +#include <Library/BaseMemoryLib.h>

> +#include <Library/DebugLib.h>

> +#include <Library/DevicePathLib.h>

> +#include <Library/IoLib.h>

> +#include <Library/MemoryAllocationLib.h>

> +#include <Library/OemMiscLib.h>

> +#include <Library/PcdLib.h>

> +#include <Library/PciHostBridgeLib.h>

> +#include <Library/PlatformPciLib.h>

> +

> +#include <Protocol/PciHostBridgeResourceAllocation.h>

> +#include <Protocol/PciRootBridgeIo.h>

> +

> +

> +#pragma pack(1)

> +typedef struct {

> +  ACPI_HID_DEVICE_PATH     AcpiDevicePath;

> +  EFI_DEVICE_PATH_PROTOCOL EndDevicePath;

> +} EFI_PCI_ROOT_BRIDGE_DEVICE_PATH;

> +#pragma pack ()

> +

> +STATIC EFI_PCI_ROOT_BRIDGE_DEVICE_PATH mEfiPciRootBridgeDevicePath = {

> +  {

> +    {

> +      ACPI_DEVICE_PATH,

> +      ACPI_DP,

> +      {

> +        (UINT8) (sizeof(ACPI_HID_DEVICE_PATH)),

> +        (UINT8) ((sizeof(ACPI_HID_DEVICE_PATH)) >> 8)

> +      }

> +    },

> +    EISA_PNP_ID(0x0A03), // PCI

> +    0

> +  }, {

> +    END_DEVICE_PATH_TYPE,

> +    END_ENTIRE_DEVICE_PATH_SUBTYPE,

> +    {

> +      END_DEVICE_PATH_LENGTH,

> +      0

> +    }

> +  }

> +};

> +

> +STATIC PCI_ROOT_BRIDGE mRootBridgeTemplate = {

> +  0,                                              // Segment

> +  0,                                              // Supports

> +  0,                                              // Attributes

> +  TRUE,                                           // DmaAbove4G

> +  FALSE,                                          // NoExtendedConfigSpace

> +  FALSE,                                          // ResourceAssigned

> +  EFI_PCI_HOST_BRIDGE_COMBINE_MEM_PMEM |          // AllocationAttributes

> +  EFI_PCI_HOST_BRIDGE_MEM64_DECODE,

> +  {

> +    // Bus

> +    0,

> +    0

> +  }, {

> +    // Io

> +    0,

> +    0,

> +    0

> +  }, {

> +    // Mem

> +    MAX_UINT64,

> +    0,

> +    0

> +  }, {

> +    // MemAbove4G

> +    MAX_UINT64,

> +    0,

> +    0

> +  }, {

> +    // PMem

> +    MAX_UINT64,

> +    0,

> +    0

> +  }, {

> +    // PMemAbove4G

> +    MAX_UINT64,

> +    0,

> +    0

> +  },

> +  (EFI_DEVICE_PATH_PROTOCOL *)&mEfiPciRootBridgeDevicePath

> +};

> +

> +STATIC

> +EFI_STATUS

> +ConstructRootBridge (

> +    PCI_ROOT_BRIDGE                     *Bridge,

> +    PCI_ROOT_BRIDGE_RESOURCE_APPETURE   *Appeture

> +    )

> +{

> +  EFI_PCI_ROOT_BRIDGE_DEVICE_PATH *DevicePath;

> +  CopyMem (Bridge, &mRootBridgeTemplate, sizeof *Bridge);

> +  Bridge->Segment = Appeture->Segment;

> +  Bridge->Bus.Base = Appeture->BusBase;

> +  Bridge->Bus.Limit = Appeture->BusLimit;

> +  Bridge->Io.Base = Appeture->IoBase;

> +  // According to UEFI 2.7, device address = host address + translation

> +  Bridge->Io.Translation = Appeture->IoBase - Appeture->CpuIoRegionBase;

> +  // IoLimit is actually an address in CPU view

> +  // TODO: improve the definition of PCI_ROOT_BRIDGE_RESOURCE_APPETURE

> +  Bridge->Io.Limit = Appeture->IoLimit + Bridge->Io.Translation;


Does this mean we incorporate the type translation into the I/O
address translation? In other words, are the CPU memory addresses
equal to the CPU I/O addresses when using this translation?

If so, I think that is incorrect. The translated I/O windows should
make up a coherent I/O space in the CPU view, and the fact that we
access I/O regions via a CPU MMIO window that involves type
translation is an implementation detail.


> +  if (Appeture->PciRegionBase > MAX_UINT32) {

> +    Bridge->MemAbove4G.Base = Appeture->PciRegionBase;

> +    Bridge->MemAbove4G.Limit = Appeture->PciRegionLimit;

> +    Bridge->MemAbove4G.Translation = Appeture->PciRegionBase - Appeture->CpuMemRegionBase;

> +  } else {

> +    Bridge->Mem.Base = Appeture->PciRegionBase;

> +    Bridge->Mem.Limit = Appeture->PciRegionLimit;

> +    Bridge->Mem.Translation = Appeture->PciRegionBase - Appeture->CpuMemRegionBase;

> +  }

> +

> +  DevicePath = AllocateCopyPool(sizeof mEfiPciRootBridgeDevicePath, &mEfiPciRootBridgeDevicePath);

> +  if (DevicePath == NULL) {

> +    DEBUG ((DEBUG_ERROR, "[%a]:[%dL] AllocatePool failed!\n", __FUNCTION__, __LINE__));

> +    return EFI_OUT_OF_RESOURCES;

> +  }

> +

> +  DevicePath->AcpiDevicePath.UID = Bridge->Segment;

> +  Bridge->DevicePath = (EFI_DEVICE_PATH_PROTOCOL *)DevicePath;

> +  return EFI_SUCCESS;

> +}

> +

> +/**

> +  Return all the root bridge instances in an array.

> +

> +  @param Count  Return the count of root bridge instances.

> +

> +  @return All the root bridge instances in an array.

> +          The array should be passed into PciHostBridgeFreeRootBridges()

> +          when it's not used.

> +**/

> +PCI_ROOT_BRIDGE *

> +EFIAPI

> +PciHostBridgeGetRootBridges (

> +  UINTN *Count

> +  )

> +{

> +  EFI_STATUS                  Status;

> +  UINTN                       Loop1;

> +  UINTN                       Loop2;

> +  UINT32                      PcieRootBridgeMask;

> +  UINTN                       RootBridgeCount = 0;

> +  PCI_ROOT_BRIDGE             *Bridges;

> +

> +  // Set default value to 0 in case we got any error.

> +  *Count = 0;

> +

> +

> +  if (!OemIsMpBoot())

> +  {

> +    PcieRootBridgeMask = PcdGet32(PcdPcieRootBridgeMask);

> +  }

> +  else

> +  {

> +    PcieRootBridgeMask = PcdGet32(PcdPcieRootBridgeMask2P);

> +  }

> +

> +  for (Loop1 = 0; Loop1 < PCIE_MAX_HOSTBRIDGE; Loop1++) {

> +    if (((PcieRootBridgeMask >> (PCIE_MAX_ROOTBRIDGE * Loop1)) & 0xFF ) == 0) {

> +      continue;

> +    }

> +

> +    for (Loop2 = 0; Loop2 < PCIE_MAX_ROOTBRIDGE; Loop2++) {

> +      if (!(((PcieRootBridgeMask >> (PCIE_MAX_ROOTBRIDGE * Loop1)) >> Loop2 ) & 0x01)) {

> +        continue;

> +      }

> +      RootBridgeCount++;

> +    }

> +  }

> +

> +  Bridges = AllocatePool (RootBridgeCount * sizeof *Bridges);

> +  if (Bridges == NULL) {

> +    DEBUG ((DEBUG_ERROR, "[%a:%d] - AllocatePool failed!\n", __FUNCTION__, __LINE__));

> +    return NULL;

> +  }

> +

> +  for (Loop1 = 0; Loop1 < PCIE_MAX_HOSTBRIDGE; Loop1++) {

> +    if (((PcieRootBridgeMask >> (PCIE_MAX_ROOTBRIDGE * Loop1)) & 0xFF ) == 0) {

> +      continue;

> +    }

> +

> +    for (Loop2 = 0; Loop2 < PCIE_MAX_ROOTBRIDGE; Loop2++) {

> +      if (!(((PcieRootBridgeMask >> (PCIE_MAX_ROOTBRIDGE * Loop1)) >> Loop2 ) & 0x01)) {

> +        continue;

> +      }

> +      Status = ConstructRootBridge (&Bridges[*Count], &mResAppeture[Loop1][Loop2]);

> +      if (EFI_ERROR (Status)) {

> +        continue;

> +      }

> +      (*Count)++;

> +    }

> +  }

> +

> +  if (*Count == 0) {

> +    FreePool (Bridges);

> +    return NULL;

> +  }

> +  return Bridges;

> +}

> +

> +/**

> +  Free the root bridge instances array returned from PciHostBridgeGetRootBridges().

> +

> +  @param Bridges The root bridge instances array.

> +  @param Count   The count of the array.

> +**/

> +VOID

> +EFIAPI

> +PciHostBridgeFreeRootBridges (

> +  PCI_ROOT_BRIDGE *Bridges,

> +  UINTN           Count

> +  )

> +{

> +  UINTN Index;

> +

> +  for (Index = 0; Index < Count; Index++) {

> +    FreePool (Bridges[Index].DevicePath);

> +  }

> +

> +  if (Bridges != NULL) {

> +    FreePool (Bridges);

> +  }

> +}

> +

> +

> +#ifndef MDEPKG_NDEBUG

> +STATIC CONST CHAR16 mPciHostBridgeLibAcpiAddressSpaceTypeStr[][4] = {

> +  L"Mem", L"I/O", L"Bus"

> +};

> +#endif

> +

> +/**

> +  Inform the platform that the resource conflict happens.

> +

> +  @param HostBridgeHandle Handle of the Host Bridge.

> +  @param Configuration    Pointer to PCI I/O and PCI memory resource

> +                          descriptors. The Configuration contains the resources

> +                          for all the root bridges. The resource for each root

> +                          bridge is terminated with END descriptor and an

> +                          additional END is appended indicating the end of the

> +                          entire resources. The resource descriptor field

> +                          values follow the description in

> +                          EFI_PCI_HOST_BRIDGE_RESOURCE_ALLOCATION_PROTOCOL

> +                          .SubmitResources().

> +**/

> +VOID

> +EFIAPI

> +PciHostBridgeResourceConflict (

> +  EFI_HANDLE                        HostBridgeHandle,

> +  VOID                              *Configuration

> +  )

> +{

> +  EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *Descriptor;

> +  UINTN                             RootBridgeIndex;

> +  DEBUG ((DEBUG_ERROR, "PciHostBridge: Resource conflict happens!\n"));

> +

> +  RootBridgeIndex = 0;

> +  Descriptor = (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *) Configuration;

> +  while (Descriptor->Desc == ACPI_ADDRESS_SPACE_DESCRIPTOR) {

> +    DEBUG ((DEBUG_ERROR, "RootBridge[%d]:\n", RootBridgeIndex++));

> +    for (; Descriptor->Desc == ACPI_ADDRESS_SPACE_DESCRIPTOR; Descriptor++) {

> +      ASSERT (Descriptor->ResType <

> +              ARRAY_SIZE (mPciHostBridgeLibAcpiAddressSpaceTypeStr)

> +              );

> +      DEBUG ((DEBUG_ERROR, " %s: Length/Alignment = 0x%lx / 0x%lx\n",

> +              mPciHostBridgeLibAcpiAddressSpaceTypeStr[Descriptor->ResType],

> +              Descriptor->AddrLen, Descriptor->AddrRangeMax

> +              ));

> +      if (Descriptor->ResType == ACPI_ADDRESS_SPACE_TYPE_MEM) {

> +        DEBUG ((DEBUG_ERROR, "     Granularity/SpecificFlag = %ld / %02x%s\n",

> +                Descriptor->AddrSpaceGranularity, Descriptor->SpecificFlag,

> +                ((Descriptor->SpecificFlag &

> +                  EFI_ACPI_MEMORY_RESOURCE_SPECIFIC_FLAG_CACHEABLE_PREFETCHABLE

> +                  ) != 0) ? L" (Prefetchable)" : L""

> +                ));

> +      }

> +    }

> +    //

> +    // Skip the END descriptor for root bridge

> +    //

> +    ASSERT (Descriptor->Desc == ACPI_END_TAG_DESCRIPTOR);

> +    Descriptor = (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *)(

> +                   (EFI_ACPI_END_TAG_DESCRIPTOR *)Descriptor + 1

> +                   );

> +  }

> +}

> --

> 2.7.4

>

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diff mbox series

Patch

diff --git a/Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.inf b/Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.inf
new file mode 100644
index 000000000000..dd451cff332c
--- /dev/null
+++ b/Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.inf
@@ -0,0 +1,51 @@ 
+## @file
+#  PCI Host Bridge Library instance for Hisilicon D0x
+#
+#  Copyright (c) 2018, Hisilicon Limited. All rights reserved.<BR>
+#  Copyright (c) 2017 - 2018, Linaro 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.
+#
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x0001000A
+  BASE_NAME                      = PciHostBridgeLib
+  FILE_GUID                      = e5c91e8a-0b2b-11e8-9533-286ed489ee9b
+  MODULE_TYPE                    = DXE_DRIVER
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = PciHostBridgeLib|DXE_DRIVER
+
+#
+# The following information is for reference only and not required by the build
+# tools.
+#
+#  VALID_ARCHITECTURES           = AARCH64 ARM
+#
+
+[Sources]
+  PciHostBridgeLib.c
+
+[Packages]
+  MdeModulePkg/MdeModulePkg.dec
+  MdePkg/MdePkg.dec
+  Silicon/Hisilicon/HisiPkg.dec
+
+[LibraryClasses]
+  BaseLib
+  BaseMemoryLib
+  DebugLib
+  DevicePathLib
+  MemoryAllocationLib
+  OemMiscLib
+
+[Pcd]
+  gHisiTokenSpaceGuid.PcdPcieRootBridgeMask
+  gHisiTokenSpaceGuid.PcdPcieRootBridgeMask2P
diff --git a/Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.c b/Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.c
new file mode 100644
index 000000000000..6aff5cdd3d76
--- /dev/null
+++ b/Platform/Hisilicon/Library/PciHostBridgeLib/PciHostBridgeLib.c
@@ -0,0 +1,304 @@ 
+/** @file
+  PCI Host Bridge Library instance for Hisilicon D0x
+
+  Copyright (c) 2018, Hisilicon Limited. All rights reserved.<BR>
+  Copyright (c) 2017 - 2018, Linaro 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 <PiDxe.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/DebugLib.h>
+#include <Library/DevicePathLib.h>
+#include <Library/IoLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/OemMiscLib.h>
+#include <Library/PcdLib.h>
+#include <Library/PciHostBridgeLib.h>
+#include <Library/PlatformPciLib.h>
+
+#include <Protocol/PciHostBridgeResourceAllocation.h>
+#include <Protocol/PciRootBridgeIo.h>
+
+
+#pragma pack(1)
+typedef struct {
+  ACPI_HID_DEVICE_PATH     AcpiDevicePath;
+  EFI_DEVICE_PATH_PROTOCOL EndDevicePath;
+} EFI_PCI_ROOT_BRIDGE_DEVICE_PATH;
+#pragma pack ()
+
+STATIC EFI_PCI_ROOT_BRIDGE_DEVICE_PATH mEfiPciRootBridgeDevicePath = {
+  {
+    {
+      ACPI_DEVICE_PATH,
+      ACPI_DP,
+      {
+        (UINT8) (sizeof(ACPI_HID_DEVICE_PATH)),
+        (UINT8) ((sizeof(ACPI_HID_DEVICE_PATH)) >> 8)
+      }
+    },
+    EISA_PNP_ID(0x0A03), // PCI
+    0
+  }, {
+    END_DEVICE_PATH_TYPE,
+    END_ENTIRE_DEVICE_PATH_SUBTYPE,
+    {
+      END_DEVICE_PATH_LENGTH,
+      0
+    }
+  }
+};
+
+STATIC PCI_ROOT_BRIDGE mRootBridgeTemplate = {
+  0,                                              // Segment
+  0,                                              // Supports
+  0,                                              // Attributes
+  TRUE,                                           // DmaAbove4G
+  FALSE,                                          // NoExtendedConfigSpace
+  FALSE,                                          // ResourceAssigned
+  EFI_PCI_HOST_BRIDGE_COMBINE_MEM_PMEM |          // AllocationAttributes
+  EFI_PCI_HOST_BRIDGE_MEM64_DECODE,
+  {
+    // Bus
+    0,
+    0
+  }, {
+    // Io
+    0,
+    0,
+    0
+  }, {
+    // Mem
+    MAX_UINT64,
+    0,
+    0
+  }, {
+    // MemAbove4G
+    MAX_UINT64,
+    0,
+    0
+  }, {
+    // PMem
+    MAX_UINT64,
+    0,
+    0
+  }, {
+    // PMemAbove4G
+    MAX_UINT64,
+    0,
+    0
+  },
+  (EFI_DEVICE_PATH_PROTOCOL *)&mEfiPciRootBridgeDevicePath
+};
+
+STATIC
+EFI_STATUS
+ConstructRootBridge (
+    PCI_ROOT_BRIDGE                     *Bridge,
+    PCI_ROOT_BRIDGE_RESOURCE_APPETURE   *Appeture
+    )
+{
+  EFI_PCI_ROOT_BRIDGE_DEVICE_PATH *DevicePath;
+  CopyMem (Bridge, &mRootBridgeTemplate, sizeof *Bridge);
+  Bridge->Segment = Appeture->Segment;
+  Bridge->Bus.Base = Appeture->BusBase;
+  Bridge->Bus.Limit = Appeture->BusLimit;
+  Bridge->Io.Base = Appeture->IoBase;
+  // According to UEFI 2.7, device address = host address + translation
+  Bridge->Io.Translation = Appeture->IoBase - Appeture->CpuIoRegionBase;
+  // IoLimit is actually an address in CPU view
+  // TODO: improve the definition of PCI_ROOT_BRIDGE_RESOURCE_APPETURE
+  Bridge->Io.Limit = Appeture->IoLimit + Bridge->Io.Translation;
+  if (Appeture->PciRegionBase > MAX_UINT32) {
+    Bridge->MemAbove4G.Base = Appeture->PciRegionBase;
+    Bridge->MemAbove4G.Limit = Appeture->PciRegionLimit;
+    Bridge->MemAbove4G.Translation = Appeture->PciRegionBase - Appeture->CpuMemRegionBase;
+  } else {
+    Bridge->Mem.Base = Appeture->PciRegionBase;
+    Bridge->Mem.Limit = Appeture->PciRegionLimit;
+    Bridge->Mem.Translation = Appeture->PciRegionBase - Appeture->CpuMemRegionBase;
+  }
+
+  DevicePath = AllocateCopyPool(sizeof mEfiPciRootBridgeDevicePath, &mEfiPciRootBridgeDevicePath);
+  if (DevicePath == NULL) {
+    DEBUG ((DEBUG_ERROR, "[%a]:[%dL] AllocatePool failed!\n", __FUNCTION__, __LINE__));
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  DevicePath->AcpiDevicePath.UID = Bridge->Segment;
+  Bridge->DevicePath = (EFI_DEVICE_PATH_PROTOCOL *)DevicePath;
+  return EFI_SUCCESS;
+}
+
+/**
+  Return all the root bridge instances in an array.
+
+  @param Count  Return the count of root bridge instances.
+
+  @return All the root bridge instances in an array.
+          The array should be passed into PciHostBridgeFreeRootBridges()
+          when it's not used.
+**/
+PCI_ROOT_BRIDGE *
+EFIAPI
+PciHostBridgeGetRootBridges (
+  UINTN *Count
+  )
+{
+  EFI_STATUS                  Status;
+  UINTN                       Loop1;
+  UINTN                       Loop2;
+  UINT32                      PcieRootBridgeMask;
+  UINTN                       RootBridgeCount = 0;
+  PCI_ROOT_BRIDGE             *Bridges;
+
+  // Set default value to 0 in case we got any error.
+  *Count = 0;
+
+
+  if (!OemIsMpBoot())
+  {
+    PcieRootBridgeMask = PcdGet32(PcdPcieRootBridgeMask);
+  }
+  else
+  {
+    PcieRootBridgeMask = PcdGet32(PcdPcieRootBridgeMask2P);
+  }
+
+  for (Loop1 = 0; Loop1 < PCIE_MAX_HOSTBRIDGE; Loop1++) {
+    if (((PcieRootBridgeMask >> (PCIE_MAX_ROOTBRIDGE * Loop1)) & 0xFF ) == 0) {
+      continue;
+    }
+
+    for (Loop2 = 0; Loop2 < PCIE_MAX_ROOTBRIDGE; Loop2++) {
+      if (!(((PcieRootBridgeMask >> (PCIE_MAX_ROOTBRIDGE * Loop1)) >> Loop2 ) & 0x01)) {
+        continue;
+      }
+      RootBridgeCount++;
+    }
+  }
+
+  Bridges = AllocatePool (RootBridgeCount * sizeof *Bridges);
+  if (Bridges == NULL) {
+    DEBUG ((DEBUG_ERROR, "[%a:%d] - AllocatePool failed!\n", __FUNCTION__, __LINE__));
+    return NULL;
+  }
+
+  for (Loop1 = 0; Loop1 < PCIE_MAX_HOSTBRIDGE; Loop1++) {
+    if (((PcieRootBridgeMask >> (PCIE_MAX_ROOTBRIDGE * Loop1)) & 0xFF ) == 0) {
+      continue;
+    }
+
+    for (Loop2 = 0; Loop2 < PCIE_MAX_ROOTBRIDGE; Loop2++) {
+      if (!(((PcieRootBridgeMask >> (PCIE_MAX_ROOTBRIDGE * Loop1)) >> Loop2 ) & 0x01)) {
+        continue;
+      }
+      Status = ConstructRootBridge (&Bridges[*Count], &mResAppeture[Loop1][Loop2]);
+      if (EFI_ERROR (Status)) {
+        continue;
+      }
+      (*Count)++;
+    }
+  }
+
+  if (*Count == 0) {
+    FreePool (Bridges);
+    return NULL;
+  }
+  return Bridges;
+}
+
+/**
+  Free the root bridge instances array returned from PciHostBridgeGetRootBridges().
+
+  @param Bridges The root bridge instances array.
+  @param Count   The count of the array.
+**/
+VOID
+EFIAPI
+PciHostBridgeFreeRootBridges (
+  PCI_ROOT_BRIDGE *Bridges,
+  UINTN           Count
+  )
+{
+  UINTN Index;
+
+  for (Index = 0; Index < Count; Index++) {
+    FreePool (Bridges[Index].DevicePath);
+  }
+
+  if (Bridges != NULL) {
+    FreePool (Bridges);
+  }
+}
+
+
+#ifndef MDEPKG_NDEBUG
+STATIC CONST CHAR16 mPciHostBridgeLibAcpiAddressSpaceTypeStr[][4] = {
+  L"Mem", L"I/O", L"Bus"
+};
+#endif
+
+/**
+  Inform the platform that the resource conflict happens.
+
+  @param HostBridgeHandle Handle of the Host Bridge.
+  @param Configuration    Pointer to PCI I/O and PCI memory resource
+                          descriptors. The Configuration contains the resources
+                          for all the root bridges. The resource for each root
+                          bridge is terminated with END descriptor and an
+                          additional END is appended indicating the end of the
+                          entire resources. The resource descriptor field
+                          values follow the description in
+                          EFI_PCI_HOST_BRIDGE_RESOURCE_ALLOCATION_PROTOCOL
+                          .SubmitResources().
+**/
+VOID
+EFIAPI
+PciHostBridgeResourceConflict (
+  EFI_HANDLE                        HostBridgeHandle,
+  VOID                              *Configuration
+  )
+{
+  EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *Descriptor;
+  UINTN                             RootBridgeIndex;
+  DEBUG ((DEBUG_ERROR, "PciHostBridge: Resource conflict happens!\n"));
+
+  RootBridgeIndex = 0;
+  Descriptor = (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *) Configuration;
+  while (Descriptor->Desc == ACPI_ADDRESS_SPACE_DESCRIPTOR) {
+    DEBUG ((DEBUG_ERROR, "RootBridge[%d]:\n", RootBridgeIndex++));
+    for (; Descriptor->Desc == ACPI_ADDRESS_SPACE_DESCRIPTOR; Descriptor++) {
+      ASSERT (Descriptor->ResType <
+              ARRAY_SIZE (mPciHostBridgeLibAcpiAddressSpaceTypeStr)
+              );
+      DEBUG ((DEBUG_ERROR, " %s: Length/Alignment = 0x%lx / 0x%lx\n",
+              mPciHostBridgeLibAcpiAddressSpaceTypeStr[Descriptor->ResType],
+              Descriptor->AddrLen, Descriptor->AddrRangeMax
+              ));
+      if (Descriptor->ResType == ACPI_ADDRESS_SPACE_TYPE_MEM) {
+        DEBUG ((DEBUG_ERROR, "     Granularity/SpecificFlag = %ld / %02x%s\n",
+                Descriptor->AddrSpaceGranularity, Descriptor->SpecificFlag,
+                ((Descriptor->SpecificFlag &
+                  EFI_ACPI_MEMORY_RESOURCE_SPECIFIC_FLAG_CACHEABLE_PREFETCHABLE
+                  ) != 0) ? L" (Prefetchable)" : L""
+                ));
+      }
+    }
+    //
+    // Skip the END descriptor for root bridge
+    //
+    ASSERT (Descriptor->Desc == ACPI_END_TAG_DESCRIPTOR);
+    Descriptor = (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *)(
+                   (EFI_ACPI_END_TAG_DESCRIPTOR *)Descriptor + 1
+                   );
+  }
+}