[PATCH v2 1/2] AMD/AmdMinBoardPkg: Implements PCI hotplug init protocol

["Abdul Lateef Attar" <abdattar@amd.com>]

From: Abdul Lateef Attar <AbdulLateef.Attar@amd.com>

Implements PCI hotplug init protocol.
Adds resources padding based on PCD values.

Cc: Abner Chang <abner.chang@amd.com>

Signed-off-by: Abdul Lateef Attar <AbdulLateef.Attar@amd.com>
---
 .../AMD/AmdMinBoardPkg/AmdMinBoardPkg.dec     |  16 +
 .../AMD/AmdMinBoardPkg/AmdMinBoardPkg.dsc     |  14 +-
 .../PciHotPlug/PciHotPlugInit.inf             |  39 +++
 .../PciHotPlug/PciHotPlugInit.c               | 331 ++++++++++++++++++
 4 files changed, 399 insertions(+), 1 deletion(-)
 create mode 100755 Platform/AMD/AmdMinBoardPkg/PciHotPlug/PciHotPlugInit.inf
 create mode 100755 Platform/AMD/AmdMinBoardPkg/PciHotPlug/PciHotPlugInit.c

diff --git a/Platform/AMD/AmdMinBoardPkg/AmdMinBoardPkg.dec b/Platform/AMD/AmdMinBoardPkg/AmdMinBoardPkg.dec
index e37b02c4cf5a..65ba08545021 100644
--- a/Platform/AMD/AmdMinBoardPkg/AmdMinBoardPkg.dec
+++ b/Platform/AMD/AmdMinBoardPkg/AmdMinBoardPkg.dec
@@ -17,3 +17,19 @@ [Defines]
   PACKAGE_GUID                   = 44F9D761-9ECB-43DD-A5AC-177E5048701B
   PACKAGE_VERSION                = 0.1
 
+[Guids]
+  gAmdMinBoardPkgTokenSpaceGuid  = {0xd4d23d79, 0x73bf, 0x460a, {0xa1, 0xc7, 0x85, 0xa3, 0xca, 0x71, 0xb9, 0x4c}}
+
+[PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
+  #
+  # PCI HotPlug Resource Padding
+  #
+  # PCI bus padding, number of bus to reserve, default 2 bus
+  gAmdMinBoardPkgTokenSpaceGuid.PcdPciHotPlugResourcePadBus|2|UINT8|0x10000003
+  # IO Resource padding in bytes, default 4KB
+  gAmdMinBoardPkgTokenSpaceGuid.PcdPciHotPlugResourcePadIo|0x00001000|UINT32|0x10000000
+  # Non-PreFetch Memory padding in bytes, default 1MB
+  gAmdMinBoardPkgTokenSpaceGuid.PcdPciHotPlugResourcePadMem|0x00100000|UINT32|0x10000002
+  # PreFetch Memory padding in bytes, default 2MB
+  gAmdMinBoardPkgTokenSpaceGuid.PcdPciHotPlugResourcePadPMem|0x00200000|UINT32|0x10000001
+
diff --git a/Platform/AMD/AmdMinBoardPkg/AmdMinBoardPkg.dsc b/Platform/AMD/AmdMinBoardPkg/AmdMinBoardPkg.dsc
index 273cd74f7842..1a8407250c56 100644
--- a/Platform/AMD/AmdMinBoardPkg/AmdMinBoardPkg.dsc
+++ b/Platform/AMD/AmdMinBoardPkg/AmdMinBoardPkg.dsc
@@ -9,7 +9,7 @@
 
 [Defines]
   DSC_SPECIFICATION           = 1.30
-  PLATFORM_GUID               = 88F8A9AE-2FA0-4D58-A6F9-05F635C05F4E
+  PLATFORM_GUID               = 939B559B-269B-4B8F-9637-44DF6575C1E2
   PLATFORM_NAME               = AmdMinBoardPkg
   PLATFORM_VERSION            = 0.1
   OUTPUT_DIRECTORY            = Build/$(PLATFORM_NAME)
@@ -25,6 +25,16 @@ [Packages]
 [LibraryClasses]
   SpcrDeviceLib|AmdMinBoardPkg/Library/SpcrDeviceLib/SpcrDeviceLib.inf
 
+[LibraryClasses.common]
+  BaseLib|MdePkg/Library/BaseLib/BaseLib.inf
+  BaseMemoryLib|MdePkg/Library/BaseMemoryLibRepStr/BaseMemoryLibRepStr.inf
+  DebugLib|MdePkg/Library/BaseDebugLibNull/BaseDebugLibNull.inf
+  MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemoryAllocationLib.inf
+  PcdLib|MdePkg/Library/BasePcdLibNull/BasePcdLibNull.inf
+  RegisterFilterLib|MdePkg/Library/RegisterFilterLibNull/RegisterFilterLibNull.inf
+  UefiBootServicesTableLib|MdePkg/Library/UefiBootServicesTableLib/UefiBootServicesTableLib.inf
+  UefiDriverEntryPoint|MdePkg/Library/UefiDriverEntryPoint/UefiDriverEntryPoint.inf
+
 [LibraryClasses.common.PEIM]
   SetCacheMtrrLib|AmdMinBoardPkg/Library/SetCacheMtrrLib/SetCacheMtrrLib.inf
 
@@ -34,3 +44,5 @@ [Components]
 [Components.IA32]
   AmdMinBoardPkg/Library/SetCacheMtrrLib/SetCacheMtrrLib.inf
 
+[Components.X64]
+  AmdMinBoardPkg/PciHotPlug/PciHotPlugInit.inf
diff --git a/Platform/AMD/AmdMinBoardPkg/PciHotPlug/PciHotPlugInit.inf b/Platform/AMD/AmdMinBoardPkg/PciHotPlug/PciHotPlugInit.inf
new file mode 100755
index 000000000000..44564df38718
--- /dev/null
+++ b/Platform/AMD/AmdMinBoardPkg/PciHotPlug/PciHotPlugInit.inf
@@ -0,0 +1,39 @@
+## @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                      = 85F78A6D-6438-4BCC-B796-759A48D00C72
+  MODULE_TYPE                    = DXE_DRIVER
+  VERSION_STRING                 = 0.1
+  ENTRY_POINT                    = PciHotPlugInitialize
+
+[Sources]
+  PciHotPlugInit.c
+
+[Packages]
+  AmdMinBoardPkg/AmdMinBoardPkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  MemoryAllocationLib
+  UefiBootServicesTableLib
+  UefiDriverEntryPoint
+
+[Protocols]
+  gEfiPciHotPlugInitProtocolGuid
+
+[Pcd]
+  gAmdMinBoardPkgTokenSpaceGuid.PcdPciHotPlugResourcePadBus
+  gAmdMinBoardPkgTokenSpaceGuid.PcdPciHotPlugResourcePadIo
+  gAmdMinBoardPkgTokenSpaceGuid.PcdPciHotPlugResourcePadMem
+  gAmdMinBoardPkgTokenSpaceGuid.PcdPciHotPlugResourcePadPMem
+
+[Depex]
+  TRUE
diff --git a/Platform/AMD/AmdMinBoardPkg/PciHotPlug/PciHotPlugInit.c b/Platform/AMD/AmdMinBoardPkg/PciHotPlug/PciHotPlugInit.c
new file mode 100755
index 000000000000..a26ca16741b8
--- /dev/null
+++ b/Platform/AMD/AmdMinBoardPkg/PciHotPlug/PciHotPlugInit.c
@@ -0,0 +1,331 @@
+/** @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>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+  @par Revision Reference:
+  This Protocol is defined in UEFI Platform Initialization Specification 1.2
+  Volume 5: Standards
+
+**/
+
+#include <Uefi/UefiBaseType.h>
+#include <Uefi/UefiSpec.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/MemoryAllocationLib.h>
+#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_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_UNSUPPORTED         This instance of EFI_PCI_HOT_PLUG_INIT_PROTOCOL
+                                  does not support the specified HPC.
+  @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;
+  }
+
+  //
+  // HPC is initialized by respective platform PI modules.
+  // Hence no extra initialization required.
+  //
+  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_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;
+
+  if ((HpcState == NULL) || (Padding == NULL) || (Attributes == NULL)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  //
+  // 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              = (UINT64)PcdGet32 (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              = (UINT64)PcdGet32 (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      = (UINT64)PcdGet32 (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_SUCCESS      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