Re: [edk2-devel] [PATCH v2 RESEND 2/4] Platform/AMD/PlatformPkg: Adds PciHotPlug init protocol implementation

["Attar, AbdulLateef (Abdul Lateef)" <AbdulLateef.Attar@amd.com>]

[AMD Official Use Only - General]

Hi Leif,
        Please see inline my reply [Abdul]
I'll address the remaining review comments and submit V3 version.
Thanks
AbduL
-----Original Message-----
From: Leif Lindholm <quic_llindhol@quicinc.com>
Sent: 17 March 2023 21:25
To: devel@edk2.groups.io; Attar, AbdulLateef (Abdul Lateef) <AbdulLateef.Attar@amd.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>; Chang, Abner <Abner.Chang@amd.com>; Michael D Kinney <michael.d.kinney@intel.com>
Subject: Re: [edk2-devel] [PATCH v2 RESEND 2/4] Platform/AMD/PlatformPkg: Adds PciHotPlug init protocol implementation

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On Fri, Mar 17, 2023 at 12:20:05 +0530, Abdul Lateef Attar via groups.io wrote:
> Adds PCI hotplug init protocol implementation.

What are some notable aspects of this initial implementation?
[Abdul]         AMD/BoardPkg and AMD/PlatformPkg will contains module/drivers to support MinPlatformPkg framework.
In initial implementation we will be adding modules which need different implementation from Intel based platforms
to adapt MinPlatformPkg, e.g. SetCacheMtrrLib library etc., as we progress more we will add more modules.

What groups of platforms is it intended to cover?
[Abdul] Its generic for all AMD processor based platforms based on latest(as of 2023) MinPlatformPkg framework.

> Signed-off-by: Abdul Lateef Attar <abdattar@amd.com>
> Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
> Cc: Leif Lindholm <quic_llindhol@quicinc.com>
> Cc: Abner Chang <abner.chang@amd.com>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> ---
>  Platform/AMD/PlatformPkg/PlatformPkg.dec      |  16 +
>  Platform/AMD/PlatformPkg/PlatformPkg.dsc      |  23 ++
>  .../PlatformPkg/PciHotPlug/PciHotPlugInit.inf |  41 +++
>  .../PlatformPkg/PciHotPlug/PciHotPlugInit.c   | 340 ++++++++++++++++++
>  4 files changed, 420 insertions(+)
>  create mode 100644
> Platform/AMD/PlatformPkg/PciHotPlug/PciHotPlugInit.inf
>  create mode 100644
> Platform/AMD/PlatformPkg/PciHotPlug/PciHotPlugInit.c
>
> diff --git a/Platform/AMD/PlatformPkg/PlatformPkg.dec
> b/Platform/AMD/PlatformPkg/PlatformPkg.dec
> index 6155860979cb..1bc38d6025c3 100644
> --- a/Platform/AMD/PlatformPkg/PlatformPkg.dec
> +++ b/Platform/AMD/PlatformPkg/PlatformPkg.dec
> @@ -13,3 +13,19 @@ [Defines]
>    PACKAGE_NAME                   = PlatformPkg
>    PACKAGE_GUID                   = 38FBA311-E2AA-4620-9A90-9A23753D1878
>    PACKAGE_VERSION                = 0.1
> +
> +[Guids]
> +  gPlatformPkgTokenSpaceGuid     = { 0x95ECA58D, 0x09B6, 0x4420, { 0xB4, 0xE7, 0x01, 0x7F, 0x6A, 0x5B, 0x26, 0x0F }}
> +
> +[PcdsDynamic, PcdsDynamicEx]
> +  #
> +  # PCI HotPlug Resource Padding
> +  #
> +  # IO Resource padding in bytes, default 4KB
> +
> +gPlatformPkgTokenSpaceGuid.PcdPciHotPlugResourcePadIO|0x00001000|UINT
> +64|0x10000000
> +  # PreFetch Memory padding in bytes, default 2MB
> +
> +gPlatformPkgTokenSpaceGuid.PcdPciHotPlugResourcePadPMem|0x00200000|UI
> +NT64|0x10000001
> +  # Non-PreFetch Memory padding in bytes, default 1MB
> +
> +gPlatformPkgTokenSpaceGuid.PcdPciHotPlugResourcePadMem|0x00100000|UIN
> +T64|0x10000002
> +  # PCI bus padding, number of bus to reserve, default 2 bus
> +
> +gPlatformPkgTokenSpaceGuid.PcdPciHotPlugResourcePadBus|2|UINT8|0x1000
> +0003
> diff --git a/Platform/AMD/PlatformPkg/PlatformPkg.dsc
> b/Platform/AMD/PlatformPkg/PlatformPkg.dsc
> index 704566b9ea73..9a693070ab3f 100644
> --- a/Platform/AMD/PlatformPkg/PlatformPkg.dsc
> +++ b/Platform/AMD/PlatformPkg/PlatformPkg.dsc
> @@ -16,5 +16,28 @@ [Defines]
>    BUILD_TARGETS               = DEBUG | RELEASE | NOOPT
>    SUPPORTED_ARCHITECTURES     = IA32 | X64
>
> +

Please don't add spurious whitespaces.

>  [Packages]
>    PlatformPkg/PlatformPkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +  MdePkg/MdePkg.dec

I won't be maintaining this code, but I generally advocate sorting these types of enumerations alphabetically in order to speed up reading.

(That's not really possible for the block below.)

> +
> +[LibraryClasses.Common]
> +
> +UefiDriverEntryPoint|MdePkg/Library/UefiDriverEntryPoint/UefiDriverEn
> +tryPoint.inf
> +
> +UefiBootServicesTableLib|MdePkg/Library/UefiBootServicesTableLib/Uefi
> +BootServicesTableLib.inf
> +
> +DebugLib|MdePkg/Library/BaseDebugLibSerialPort/BaseDebugLibSerialPort
> +.inf
> +
> +MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemory
> +AllocationLib.inf
> +  BaseMemoryLib|MdePkg/Library/BaseMemoryLib/BaseMemoryLib.inf
> +  BaseLib|MdePkg/Library/BaseLib/BaseLib.inf
> +  PcdLib|MdePkg/Library/DxePcdLib/DxePcdLib.inf
> +
> +RegisterFilterLib|MdePkg/Library/RegisterFilterLibNull/RegisterFilter
> +LibNull.inf
> +
> +SerialPortLib|MdeModulePkg/Library/BaseSerialPortLib16550/BaseSerialP
> +ortLib16550.inf
> +  PrintLib|MdePkg/Library/BasePrintLib/BasePrintLib.inf
> +
> +DebugPrintErrorLevelLib|MdePkg/Library/BaseDebugPrintErrorLevelLib/Ba
> +seDebugPrintErrorLevelLib.inf
> +  IoLib|MdePkg/Library/BaseIoLibIntrinsic/BaseIoLibIntrinsic.inf
> +
> +PlatformHookLib|MdeModulePkg/Library/BasePlatformHookLibNull/BasePlat
> +formHookLibNull.inf
> +  PciLib|MdePkg/Library/BasePciLibPciExpress/BasePciLibPciExpress.inf
> +
> +PciExpressLib|MdePkg/Library/BasePciExpressLib/BasePciExpressLib.inf
> +
> +[Components.X64]
> +  PlatformPkg/PciHotPlug/PciHotPlugInit.inf
> diff --git a/Platform/AMD/PlatformPkg/PciHotPlug/PciHotPlugInit.inf
> b/Platform/AMD/PlatformPkg/PciHotPlug/PciHotPlugInit.inf
> new file mode 100644
> index 000000000000..0079c4acf14e
> --- /dev/null
> +++ b/Platform/AMD/PlatformPkg/PciHotPlug/PciHotPlugInit.inf
> @@ -0,0 +1,41 @@
> +## @file
> +# This driver implements EFI_PCI_HOT_PLUG_INIT_PROTOCOL.
> +# Adds resource padding information, for PCIe hotplug purposes.
> +#
> +# Copyright (C) 2023 Advanced Micro Devices, Inc. All rights reserved
> +# SPDX-License-Identifier: BSD-2-Clause-Patent ##
> +
> +[Defines]
> +  INF_VERSION                    = 1.29
> +  BASE_NAME                      = PciHotPlugInit
> +  FILE_GUID                      = 8B67D95F-78B7-484F-8F16-5F22AB388B0C
> +  MODULE_TYPE                    = DXE_DRIVER
> +  VERSION_STRING                 = 0.1
> +  ENTRY_POINT                    = PciHotPlugInitialize
> +
> +[Sources]
> +  PciHotPlugInit.c
> +
> +[Packages]
> +  MdeModulePkg/MdeModulePkg.dec
> +  MdePkg/MdePkg.dec
> +  PlatformPkg/PlatformPkg.dec

But these would benefit from sorting

> +
> +[LibraryClasses]
> +  UefiDriverEntryPoint
> +  UefiBootServicesTableLib
> +  DebugLib
> +  MemoryAllocationLib

And these

> +
> +[Protocols]
> +  gEfiPciHotPlugInitProtocolGuid
> +
> +[Pcd]
> +  gPlatformPkgTokenSpaceGuid.PcdPciHotPlugResourcePadIO
> +  gPlatformPkgTokenSpaceGuid.PcdPciHotPlugResourcePadPMem
> +  gPlatformPkgTokenSpaceGuid.PcdPciHotPlugResourcePadMem
> +  gPlatformPkgTokenSpaceGuid.PcdPciHotPlugResourcePadBus
> +
> +[Depex]
> +  TRUE
> diff --git a/Platform/AMD/PlatformPkg/PciHotPlug/PciHotPlugInit.c
> b/Platform/AMD/PlatformPkg/PciHotPlug/PciHotPlugInit.c
> new file mode 100644
> index 000000000000..b977406bbcae
> --- /dev/null
> +++ b/Platform/AMD/PlatformPkg/PciHotPlug/PciHotPlugInit.c
> @@ -0,0 +1,340 @@
> +/** @file
> +  This file declares EFI PCI Hot Plug Init Protocol.
> +
> +  This protocol provides the necessary functionality to initialize
> + the Hot Plug  Controllers (HPCs) and the buses that they control.
> + This protocol also provides  information regarding resource padding.
> +
> +  @par Note:
> +    This source has the reference of OVMF PciHotPluginit.c and Intel platform PciHotPlug.c.
> +
> +    This protocol is required only on platforms that support one or more PCI Hot
> +    Plug* slots or CardBus sockets.
> +
> +  The EFI_PCI_HOT_PLUG_INIT_PROTOCOL provides a mechanism for the PCI
> + bus enumerator  to properly initialize the HPCs and CardBus sockets that require initialization.
> +  The HPC initialization takes place before the PCI enumeration process is complete.
> +  There cannot be more than one instance of this protocol in a
> + system. This protocol  is installed on its own separate handle.
> +
> +  Because the system may include multiple HPCs, one instance of this
> + protocol  should represent all of them. The protocol functions use
> + the device path of  the HPC to identify the HPC. When the PCI bus
> + enumerator finds a root HPC, it  will call
> + EFI_PCI_HOT_PLUG_INIT_PROTOCOL.InitializeRootHpc(). If
> + InitializeRootHpc()  is unable to initialize a root HPC, the PCI
> + enumerator will ignore that root HPC  and continue the enumeration process. If the HPC is not initialized, the devices  that it controls may not be initialized, and no resource padding will be provided.
> +
> +  From the standpoint of the PCI bus enumerator, HPCs are divided
> + into the following  two classes:
> +
> +    - Root HPC:
> +        These HPCs must be initialized by calling InitializeRootHpc() during the
> +        enumeration process. These HPCs will also require resource padding. The
> +        platform code must have a priori knowledge of these devices and must know
> +        how to initialize them. There may not be any way to access their PCI
> +        configuration space before the PCI enumerator programs all the upstream
> +        bridges and thus enables the path to these devices. The PCI bus enumerator
> +        is responsible for determining the PCI bus address of the HPC before it
> +        calls InitializeRootHpc().
> +    - Nonroot HPC:
> +        These HPCs will not need explicit initialization during enumeration process.
> +        These HPCs will require resource padding. The platform code does not have
> +        to have a priori knowledge of these devices.
> +
> +  Copyright (c) 2007 - 2018, Intel Corporation. All rights
> + reserved.<BR>  Copyright (C) 2016, Red Hat, Inc.<BR>  Copyright (C)
> + 2023 Advanced Micro Devices, Inc. All rights reserved.<BR>
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +  @par Revision Reference:
> +  This Protocol is defined in UEFI Platform Initialization
> + Specification 1.2

I know you say above that this is based on existing code, but 1.2 is ancient. Latest version is 1.7 - is there anything missing from being compliant with that version?

> +  Volume 5: Standards
> +
> +**/
> +
> +#include <Uefi/UefiBaseType.h>
> +#include <Uefi/UefiSpec.h>
> +#include <Library/UefiBootServicesTableLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/MemoryAllocationLib.h>

I (personally) also like to sort include files within each Uefi/Library/Protocol group alphabetically.

/
    Leif

> +#include <Protocol/PciHotPlugInit.h>
> +
> +//
> +// The protocol interface this driver produces.
> +//
> +STATIC EFI_PCI_HOT_PLUG_INIT_PROTOCOL  mPciHotPlugInit;
> +
> +/**
> +  Returns a list of root Hot Plug Controllers (HPCs) that require
> +initialization
> +  during the boot process.
> +
> +  This procedure returns a list of root HPCs. The PCI bus driver must
> + initialize  these controllers during the boot process. The PCI bus
> + driver may or may not be  able to detect these HPCs. If the platform
> + includes a PCI-to-CardBus bridge, it  can be included in this list
> + if it requires initialization.  The HpcList must be  self
> + consistent. An HPC cannot control any of its parent buses. Only one
> + HPC can  control a PCI bus. Because this list includes only root HPCs, no HPC in the list  can be a child of another HPC. This policy must be enforced by the
> +  EFI_PCI_HOT_PLUG_INIT_PROTOCOL.   The PCI bus driver may not check for such
> +  invalid conditions.  The callee allocates the buffer HpcList
> +
> +  @param[in]  This       Pointer to the EFI_PCI_HOT_PLUG_INIT_PROTOCOL instance.
> +  @param[out] HpcCount   The number of root HPCs that were returned.
> +  @param[out] HpcList    The list of root HPCs. HpcCount defines the number of
> +                         elements in this list.
> +
> +  @retval EFI_SUCCESS             HpcList was returned.
> +  @retval EFI_OUT_OF_RESOURCES    HpcList was not returned due to insufficient
> +                                  resources.
> +  @retval EFI_INVALID_PARAMETER   HpcCount is NULL or HpcList is NULL.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +GetRootHpcList (
> +  IN  EFI_PCI_HOT_PLUG_INIT_PROTOCOL  *This,
> +  OUT UINTN                           *HpcCount,
> +  OUT EFI_HPC_LOCATION                **HpcList
> +  )
> +{
> +  if ((HpcCount == NULL) || (HpcList == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  // Platform BIOS not doing any extra/special HPC initialization  //
> + Hence returning the HpcCount as zero and HpcList as NULL  //
> + *HpcCount = 0;  *HpcList  = NULL;
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Initializes one root Hot Plug Controller (HPC). This process may
> +causes
> +  initialization of its subordinate buses.
> +
> +  This function initializes the specified HPC. At the end of
> + initialization,  the hot-plug slots or sockets (controlled by this
> + HPC) are powered and are  connected to the bus. All the necessary
> + registers in the HPC are set up. For  a Standard (PCI) Hot Plug
> + Controller (SHPC), the registers that must be set  up are defined in
> + the PCI Standard Hot Plug Controller and Subsystem  Specification.
> +
> +  @param[in]  This            Pointer to the EFI_PCI_HOT_PLUG_INIT_PROTOCOL instance.
> +  @param[in]  HpcDevicePath   The device path to the HPC that is being initialized.
> +  @param[in]  HpcPciAddress   The address of the HPC function on the PCI bus.
> +  @param[in]  Event           The event that should be signaled when the HPC
> +                              initialization is complete.  Set to NULL if the
> +                              caller wants to wait until the entire initialization
> +                              process is complete.
> +  @param[out] HpcState        The state of the HPC hardware. The state is
> +                              EFI_HPC_STATE_INITIALIZED or EFI_HPC_STATE_ENABLED.
> +
> +  @retval EFI_SUCCESS             If Event is NULL, the specific HPC was successfully
> +                                  initialized. If Event is not NULL, Event will be
> +                                  signaled at a later time when initialization is complete.
> +  @retval EFI_UNSUPPORTED         This instance of EFI_PCI_HOT_PLUG_INIT_PROTOCOL
> +                                  does not support the specified HPC.
> +  @retval EFI_OUT_OF_RESOURCES    Initialization failed due to insufficient
> +                                  resources.
> +  @retval EFI_INVALID_PARAMETER   HpcState is NULL.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +InitializeRootHpc (
> +  IN  EFI_PCI_HOT_PLUG_INIT_PROTOCOL *This,
> +  IN  EFI_DEVICE_PATH_PROTOCOL *HpcDevicePath,
> +  IN  UINT64 HpcPciAddress,
> +  IN  EFI_EVENT Event, OPTIONAL
> +  OUT EFI_HPC_STATE                   *HpcState
> +  )
> +{
> +  if (HpcState == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  // This Platform doesnt have any non-enumerated HPC.
> +  // Hence no extra initialization required from Platform BIOS.
> +  //
> +  return EFI_UNSUPPORTED;
> +}
> +
> +/**
> +  Returns the resource padding that is required by the PCI bus that
> +is controlled
> +  by the specified Hot Plug Controller (HPC).
> +
> +  This function returns the resource padding that is required by the
> + PCI bus that  is controlled by the specified HPC. This member
> + function is called for all the  root HPCs and nonroot HPCs that are
> + detected by the PCI bus enumerator. This  function will be called
> + before PCI resource allocation is completed. This function  must be
> + called after all the root HPCs, with the possible exception of a  PCI-to-CardBus bridge, have completed initialization.
> +
> +  @param[in]  This            Pointer to the EFI_PCI_HOT_PLUG_INIT_PROTOCOL instance.
> +  @param[in]  HpcDevicePath   The device path to the HPC.
> +  @param[in]  HpcPciAddress   The address of the HPC function on the PCI bus.
> +  @param[out] HpcState        The state of the HPC hardware.
> +  @param[out] Padding         The amount of resource padding that is required by the
> +                              PCI bus under the control of the specified HPC.
> +  @param[out] Attributes      Describes how padding is accounted for. The padding
> +                              is returned in the form of ACPI 2.0 resource descriptors.
> +
> +  @retval EFI_SUCCESS             The resource padding was successfully returned.
> +  @retval EFI_UNSUPPORTED         This instance of the EFI_PCI_HOT_PLUG_INIT_PROTOCOL
> +                                  does not support the specified HPC.
> +  @retval EFI_NOT_READY           This function was called before HPC initialization
> +                                  is complete.
> +  @retval EFI_INVALID_PARAMETER   HpcState or Padding or Attributes is NULL.
> +  @retval EFI_OUT_OF_RESOURCES    ACPI 2.0 resource descriptors for Padding
> +                                  cannot be allocated due to insufficient resources.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +GetResourcePadding (
> +  IN  EFI_PCI_HOT_PLUG_INIT_PROTOCOL  *This,
> +  IN  EFI_DEVICE_PATH_PROTOCOL        *HpcDevicePath,
> +  IN  UINT64                          HpcPciAddress,
> +  OUT EFI_HPC_STATE                   *HpcState,
> +  OUT VOID                            **Padding,
> +  OUT EFI_HPC_PADDING_ATTRIBUTES      *Attributes
> +  )
> +{
> +  EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR  *PaddingResource;
> +
> +  //
> +  // Need total 5 resources
> +  // 1 - IO resource
> +  // 2 - Mem resource
> +  // 3 - PMem resource
> +  // 4 - Bus resource
> +  // 5 - end tag resource
> +  PaddingResource = AllocateZeroPool (4 * sizeof
> + (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) + sizeof (EFI_ACPI_END_TAG_DESCRIPTOR));  if (PaddingResource == NULL) {
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  *Padding = (VOID *)PaddingResource;
> +
> +  //
> +  // Padding for bus
> +  //
> +  *Attributes = EfiPaddingPciBus;
> +
> +  PaddingResource->Desc = ACPI_ADDRESS_SPACE_DESCRIPTOR;
> + PaddingResource->Len  = (UINT16)(
> +                                   sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) -
> +                                   OFFSET_OF (
> +                                     EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR,
> +                                     ResType
> +                                     )
> +                                   );
> +  PaddingResource->ResType      = ACPI_ADDRESS_SPACE_TYPE_BUS;
> +  PaddingResource->GenFlag      = 0x0;
> +  PaddingResource->SpecificFlag = 0;
> +  PaddingResource->AddrRangeMin = 0;
> +  PaddingResource->AddrRangeMax = 0;
> +  PaddingResource->AddrLen      = PcdGet8 (PcdPciHotPlugResourcePadBus);
> +
> +  //
> +  // Padding for non-prefetchable memory  //  PaddingResource++;
> + PaddingResource->Desc = ACPI_ADDRESS_SPACE_DESCRIPTOR;
> + PaddingResource->Len  = (UINT16)(
> +                                   sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) -
> +                                   OFFSET_OF (
> +                                     EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR,
> +                                     ResType
> +                                     )
> +                                   );
> +  PaddingResource->ResType              = ACPI_ADDRESS_SPACE_TYPE_MEM;
> +  PaddingResource->GenFlag              = 0x0;
> +  PaddingResource->AddrSpaceGranularity = 32;
> +  PaddingResource->SpecificFlag         = EFI_ACPI_MEMORY_RESOURCE_SPECIFIC_FLAG_NON_CACHEABLE;
> +  PaddingResource->AddrRangeMin         = 0;
> +  PaddingResource->AddrLen              = PcdGet64 (PcdPciHotPlugResourcePadMem);
> +  PaddingResource->AddrRangeMax         = PaddingResource->AddrLen - 1;
> +
> +  //
> +  // Padding for prefetchable memory
> +  //
> +  PaddingResource++;
> +  PaddingResource->Desc = ACPI_ADDRESS_SPACE_DESCRIPTOR;
> + PaddingResource->Len  = (UINT16)(
> +                                   sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) -
> +                                   OFFSET_OF (
> +                                     EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR,
> +                                     ResType
> +                                     )
> +                                   );
> +  PaddingResource->ResType              = ACPI_ADDRESS_SPACE_TYPE_MEM;
> +  PaddingResource->GenFlag              = 0x0;
> +  PaddingResource->AddrSpaceGranularity = 32;
> +  PaddingResource->SpecificFlag         = EFI_ACPI_MEMORY_RESOURCE_SPECIFIC_FLAG_CACHEABLE_PREFETCHABLE;
> +  PaddingResource->AddrLen              = PcdGet64 (PcdPciHotPlugResourcePadPMem);
> +  PaddingResource->AddrRangeMax         = PaddingResource->AddrLen - 1;
> +
> +  //
> +  // Padding for I/O
> +  //
> +  PaddingResource++;
> +  PaddingResource->Desc = ACPI_ADDRESS_SPACE_DESCRIPTOR;
> + PaddingResource->Len  = (UINT16)(
> +                                   sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) -
> +                                   OFFSET_OF (
> +                                     EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR,
> +                                     ResType
> +                                     )
> +                                   );
> +  PaddingResource->ResType      = ACPI_ADDRESS_SPACE_TYPE_IO;
> +  PaddingResource->GenFlag      = 0x0;
> +  PaddingResource->SpecificFlag = 0;
> +  PaddingResource->AddrRangeMin = 0;
> +  PaddingResource->AddrLen      = PcdGet64 (PcdPciHotPlugResourcePadIO);
> +  PaddingResource->AddrRangeMax = PaddingResource->AddrLen - 1;
> +
> +  //
> +  // Terminate the entries.
> +  //
> +  PaddingResource++;
> +  ((EFI_ACPI_END_TAG_DESCRIPTOR *)PaddingResource)->Desc     = ACPI_END_TAG_DESCRIPTOR;
> +  ((EFI_ACPI_END_TAG_DESCRIPTOR *)PaddingResource)->Checksum = 0x0;
> +
> +  *HpcState = EFI_HPC_STATE_INITIALIZED | EFI_HPC_STATE_ENABLED;
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Entry point for this driver.
> +
> +  @param[in] ImageHandle  Image handle of this driver.
> +  @param[in] SystemTable  Pointer to SystemTable.
> +
> +  @retval EFI_SUCESS       Driver has loaded successfully.
> +  @return                  Error codes from lower level functions.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +PciHotPlugInitialize (
> +  IN EFI_HANDLE        ImageHandle,
> +  IN EFI_SYSTEM_TABLE  *SystemTable
> +  )
> +{
> +  mPciHotPlugInit.GetRootHpcList     = GetRootHpcList;
> +  mPciHotPlugInit.InitializeRootHpc  = InitializeRootHpc;
> +  mPciHotPlugInit.GetResourcePadding = GetResourcePadding;
> +  return gBS->InstallMultipleProtocolInterfaces (
> +                &ImageHandle,
> +                &gEfiPciHotPlugInitProtocolGuid,
> +                &mPciHotPlugInit,
> +                NULL
> +                );
> +}
> --
> 2.25.1
>
>
>
> 
>
>