OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.c - third_party/edk2 - Git at Google

 /** @file
   This driver implements EFI_PCI_HOT_PLUG_INIT_PROTOCOL, providing the PCI bus
   driver with resource padding information, for PCIe hotplug purposes.

   Copyright (C) 2016, Red Hat, Inc.

   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 <IndustryStandard/Acpi10.h>

 #include <Library/DebugLib.h>
 #include <Library/DevicePathLib.h>
 #include <Library/MemoryAllocationLib.h>
 #include <Library/UefiBootServicesTableLib.h>

 #include <Protocol/PciHotPlugInit.h>
 #include <Protocol/PciRootBridgeIo.h>

 //
 // The protocol interface this driver produces.
 //
 // Refer to 12.6 "PCI Hot Plug PCI Initialization Protocol" in the Platform
 // Init 1.4a Spec, Volume 5.
 //
 STATIC EFI_PCI_HOT_PLUG_INIT_PROTOCOL mPciHotPlugInit;


 //
 // Resource padding template for the GetResourcePadding() protocol member
 // function.
 //
 // Refer to Table 8 "ACPI 2.0 & 3.0 QWORD Address Space Descriptor Usage" in
 // the Platform Init 1.4a Spec, Volume 5.
 //
 // This structure is interpreted by the ApplyResourcePadding() function in the
 // edk2 PCI Bus UEFI_DRIVER.
 //
 #pragma pack (1)
 typedef struct {
   EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR MmioPadding;
   EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR IoPadding;
   EFI_ACPI_END_TAG_DESCRIPTOR       EndDesc;
 } RESOURCE_PADDING;
 #pragma pack ()

 STATIC CONST RESOURCE_PADDING mPadding = {
   //
   // MmioPadding
   //
   {
     ACPI_ADDRESS_SPACE_DESCRIPTOR,                 // Desc
     (UINT16)(                                      // Len
       sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) -
       OFFSET_OF (
         EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR,
         ResType
         )
       ),
     ACPI_ADDRESS_SPACE_TYPE_MEM, // ResType
     0,                           // GenFlag:
                                  //   ignored
     0,                           // SpecificFlag:
                                  //   non-prefetchable
     64,                          // AddrSpaceGranularity:
                                  //   reserve 64-bit aperture
     0,                           // AddrRangeMin:
                                  //   ignored
     SIZE_2MB - 1,                // AddrRangeMax:
                                  //   align at 2MB
     0,                           // AddrTranslationOffset:
                                  //   ignored
     SIZE_2MB                     // AddrLen:
                                  //   2MB padding
   },

   //
   // IoPadding
   //
   {
     ACPI_ADDRESS_SPACE_DESCRIPTOR,                 // Desc
     (UINT16)(                                      // Len
       sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) -
       OFFSET_OF (
         EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR,
         ResType
         )
       ),
     ACPI_ADDRESS_SPACE_TYPE_IO,// ResType
     0,                          // GenFlag:
                                 //   ignored
     0,                          // SpecificFlag:
                                 //   ignored
     0,                          // AddrSpaceGranularity:
                                 //   ignored
     0,                          // AddrRangeMin:
                                 //   ignored
     512 - 1,                    // AddrRangeMax:
                                 //   align at 512 IO ports
     0,                          // AddrTranslationOffset:
                                 //   ignored
     512                         // AddrLen:
                                 //   512 IO ports
   },

   //
   // EndDesc
   //
   {
     ACPI_END_TAG_DESCRIPTOR, // Desc
     0                        // Checksum: to be ignored
   }
 };


 /**
   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.
 **/
 STATIC
 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;
   }

   //
   // There are no top-level (i.e., un-enumerable) hot-plug controllers in QEMU
   // that would require special initialization.
   //
   *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.
 **/
 STATIC
 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
   )
 {
   //
   // This function should never be called, due to the information returned by
   // GetRootHpcList().
   //
   ASSERT (FALSE);

   if (HpcState == NULL) {
     return EFI_INVALID_PARAMETER;
   }
   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[in]  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.
 **/
 STATIC
 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
   )
 {
   DEBUG_CODE (
     EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL_PCI_ADDRESS *Address;
     CHAR16                                      *DevicePathString;

     Address = (EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL_PCI_ADDRESS *)&HpcPciAddress;
     DevicePathString = ConvertDevicePathToText (HpcDevicePath, FALSE, FALSE);

     DEBUG ((EFI_D_VERBOSE, "%a: Address=%02x:%02x.%x DevicePath=%s\n",
       __FUNCTION__, Address->Bus, Address->Device, Address->Function,
       (DevicePathString == NULL) ? L"<unavailable>" : DevicePathString));

     if (DevicePathString != NULL) {
       FreePool (DevicePathString);
     }
     );

   if (HpcState == NULL || Padding == NULL || Attributes == NULL) {
     return EFI_INVALID_PARAMETER;
   }

   *Padding = AllocateCopyPool (sizeof mPadding, &mPadding);
   if (*Padding == NULL) {
     return EFI_OUT_OF_RESOURCES;
   }

   //
   // Resource padding is required.
   //
   *HpcState = EFI_HPC_STATE_INITIALIZED | EFI_HPC_STATE_ENABLED;

   //
   // The padding should be applied at PCI bus level, and considered by upstream
   // bridges, recursively.
   //
   *Attributes = EfiPaddingPciBus;
   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
 DriverInitialize (
   IN EFI_HANDLE       ImageHandle,
   IN EFI_SYSTEM_TABLE *SystemTable
   )
 {
   EFI_STATUS Status;

   mPciHotPlugInit.GetRootHpcList = GetRootHpcList;
   mPciHotPlugInit.InitializeRootHpc = InitializeRootHpc;
   mPciHotPlugInit.GetResourcePadding = GetResourcePadding;
   Status = gBS->InstallMultipleProtocolInterfaces (&ImageHandle,
                   &gEfiPciHotPlugInitProtocolGuid, &mPciHotPlugInit, NULL);
   return Status;
 }
	/** @file
	This driver implements EFI_PCI_HOT_PLUG_INIT_PROTOCOL, providing the PCI bus
	driver with resource padding information, for PCIe hotplug purposes.

	Copyright (C) 2016, Red Hat, Inc.

	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 <IndustryStandard/Acpi10.h>

	#include <Library/DebugLib.h>
	#include <Library/DevicePathLib.h>
	#include <Library/MemoryAllocationLib.h>
	#include <Library/UefiBootServicesTableLib.h>

	#include <Protocol/PciHotPlugInit.h>
	#include <Protocol/PciRootBridgeIo.h>

	//
	// The protocol interface this driver produces.
	//
	// Refer to 12.6 "PCI Hot Plug PCI Initialization Protocol" in the Platform
	// Init 1.4a Spec, Volume 5.
	//
	STATIC EFI_PCI_HOT_PLUG_INIT_PROTOCOL mPciHotPlugInit;


	//
	// Resource padding template for the GetResourcePadding() protocol member
	// function.
	//
	// Refer to Table 8 "ACPI 2.0 & 3.0 QWORD Address Space Descriptor Usage" in
	// the Platform Init 1.4a Spec, Volume 5.
	//
	// This structure is interpreted by the ApplyResourcePadding() function in the
	// edk2 PCI Bus UEFI_DRIVER.
	//
	#pragma pack (1)
	typedef struct {
	EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR MmioPadding;
	EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR IoPadding;
	EFI_ACPI_END_TAG_DESCRIPTOR EndDesc;
	} RESOURCE_PADDING;
	#pragma pack ()

	STATIC CONST RESOURCE_PADDING mPadding = {
	//
	// MmioPadding
	//
	{
	ACPI_ADDRESS_SPACE_DESCRIPTOR, // Desc
	(UINT16)( // Len
	sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) -
	OFFSET_OF (
	EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR,
	ResType
	)
	),
	ACPI_ADDRESS_SPACE_TYPE_MEM, // ResType
	0, // GenFlag:
	// ignored
	0, // SpecificFlag:
	// non-prefetchable
	64, // AddrSpaceGranularity:
	// reserve 64-bit aperture
	0, // AddrRangeMin:
	// ignored
	SIZE_2MB - 1, // AddrRangeMax:
	// align at 2MB
	0, // AddrTranslationOffset:
	// ignored
	SIZE_2MB // AddrLen:
	// 2MB padding
	},

	//
	// IoPadding
	//
	{
	ACPI_ADDRESS_SPACE_DESCRIPTOR, // Desc
	(UINT16)( // Len
	sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) -
	OFFSET_OF (
	EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR,
	ResType
	)
	),
	ACPI_ADDRESS_SPACE_TYPE_IO,// ResType
	0, // GenFlag:
	// ignored
	0, // SpecificFlag:
	// ignored
	0, // AddrSpaceGranularity:
	// ignored
	0, // AddrRangeMin:
	// ignored
	512 - 1, // AddrRangeMax:
	// align at 512 IO ports
	0, // AddrTranslationOffset:
	// ignored
	512 // AddrLen:
	// 512 IO ports
	},

	//
	// EndDesc
	//
	{
	ACPI_END_TAG_DESCRIPTOR, // Desc
	0 // Checksum: to be ignored
	}
	};


	/**
	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.
	**/
	STATIC
	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;
	}

	//
	// There are no top-level (i.e., un-enumerable) hot-plug controllers in QEMU
	// that would require special initialization.
	//
	*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.
	**/
	STATIC
	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
	)
	{
	//
	// This function should never be called, due to the information returned by
	// GetRootHpcList().
	//
	ASSERT (FALSE);

	if (HpcState == NULL) {
	return EFI_INVALID_PARAMETER;
	}
	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[in] 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.
	**/
	STATIC
	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
	)
	{
	DEBUG_CODE (
	EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL_PCI_ADDRESS *Address;
	CHAR16 *DevicePathString;

	Address = (EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL_PCI_ADDRESS *)&HpcPciAddress;
	DevicePathString = ConvertDevicePathToText (HpcDevicePath, FALSE, FALSE);

	DEBUG ((EFI_D_VERBOSE, "%a: Address=%02x:%02x.%x DevicePath=%s\n",
	__FUNCTION__, Address->Bus, Address->Device, Address->Function,
	(DevicePathString == NULL) ? L"<unavailable>" : DevicePathString));

	if (DevicePathString != NULL) {
	FreePool (DevicePathString);
	}
	);

	if (HpcState == NULL \|\| Padding == NULL \|\| Attributes == NULL) {
	return EFI_INVALID_PARAMETER;
	}

	*Padding = AllocateCopyPool (sizeof mPadding, &mPadding);
	if (*Padding == NULL) {
	return EFI_OUT_OF_RESOURCES;
	}

	//
	// Resource padding is required.
	//
	*HpcState = EFI_HPC_STATE_INITIALIZED \| EFI_HPC_STATE_ENABLED;

	//
	// The padding should be applied at PCI bus level, and considered by upstream
	// bridges, recursively.
	//
	*Attributes = EfiPaddingPciBus;
	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
	DriverInitialize (
	IN EFI_HANDLE ImageHandle,
	IN EFI_SYSTEM_TABLE *SystemTable
	)
	{
	EFI_STATUS Status;

	mPciHotPlugInit.GetRootHpcList = GetRootHpcList;
	mPciHotPlugInit.InitializeRootHpc = InitializeRootHpc;
	mPciHotPlugInit.GetResourcePadding = GetResourcePadding;
	Status = gBS->InstallMultipleProtocolInterfaces (&ImageHandle,
	&gEfiPciHotPlugInitProtocolGuid, &mPciHotPlugInit, NULL);
	return Status;
	}