Re: [staging/edk2-redfish-client RedfishFeatureCore PATCH 2/3] RedfishClientPkg/RedfishFeatureCoreDxe: Redfish Feature Core DXE driver

["Abner Chang" <abner.chang@hpe.com>]

Thanks
All issues were addressed before merged to edk2-staging edk2-redfish-clinet branch.
Abner

> -----Original Message-----
> From: Wang, Nickle (HPS SW)
> Sent: Sunday, August 8, 2021 8:55 PM
> To: Chang, Abner (HPS SW/FW Technologist) <abner.chang@hpe.com>;
> devel@edk2.groups.io
> Cc: Liming Gao <gaoliming@byosoft.com.cn>
> Subject: RE: [staging/edk2-redfish-client RedfishFeatureCore PATCH 2/3]
> RedfishClientPkg/RedfishFeatureCoreDxe: Redfish Feature Core DXE driver
> 
> Minor issue as inline below.
> 
> Thanks,
> Nickle
> 
> -----Original Message-----
> From: Chang, Abner (HPS SW/FW Technologist) <abner.chang@hpe.com>
> Sent: Tuesday, July 27, 2021 10:55 PM
> To: devel@edk2.groups.io
> Cc: Wang, Nickle (HPS SW) <nickle.wang@hpe.com>; Liming Gao
> <gaoliming@byosoft.com.cn>
> Subject: [staging/edk2-redfish-client RedfishFeatureCore PATCH 2/3]
> RedfishClientPkg/RedfishFeatureCoreDxe: Redfish Feature Core DXE driver
> 
> EDKII Redfish Feature Core DXE driver provides the protocol interface to
> the auto-generated Redfish feature driver to register itself for the
> Redfish resource URI it manages. Refer to the Readme.md for the details.
> 
> Signed-off-by: Abner Chang <abner.chang@hpe.com>
> Cc: Nickle Wang <nickle.wang@hpe.com>
> Cc: Liming Gao <gaoliming@byosoft.com.cn>
> ---
>  RedfishClientPkg/RedfishClientPkg.dec         |  13 +-
>  .../RedfishClientComponents.dsc.inc           |   2 +
>  RedfishClientPkg/RedfishClient.fdf.inc        |   1 +
>  .../RedfishFeatureCoreDxe.inf                 |  49 +++
>  .../Include/Protocol/EdkIIRedfishFeature.h    | 116 ++++++
>  .../RedfishFeatureCoreDxe.h                   |  43 ++
>  .../RedfishFeatureCoreDxe.c                   | 382 ++++++++++++++++++
>  RedfishClientPkg/Readme.md                    |  36 ++
>  8 files changed, 641 insertions(+), 1 deletion(-)
>  create mode 100644
> RedfishClientPkg/RedfishFeatureCoreDxe/RedfishFeatureCoreDxe.inf
>  create mode 100644
> RedfishClientPkg/Include/Protocol/EdkIIRedfishFeature.h
>  create mode 100644
> RedfishClientPkg/RedfishFeatureCoreDxe/RedfishFeatureCoreDxe.h
>  create mode 100644
> RedfishClientPkg/RedfishFeatureCoreDxe/RedfishFeatureCoreDxe.c
> 
> diff --git a/RedfishClientPkg/RedfishClientPkg.dec
> b/RedfishClientPkg/RedfishClientPkg.dec
> index 4038a47bd5..6da0468e65 100644
> --- a/RedfishClientPkg/RedfishClientPkg.dec
> +++ b/RedfishClientPkg/RedfishClientPkg.dec
> @@ -15,10 +15,21 @@
>  [Includes]
>    Include
> 
> -
>  [LibraryClasses]
> 
>  [Protocols]
> +  ## Include/Protocol/EdkIIRedfishFeature.h
> +  gEdkIIRedfishFeatureProtocolGuid = { 0x785CC694, 0x4930, 0xEFBF, { 0x2A,
> 0xCB, 0xA4, 0xB6, 0xA1, 0xCC, 0xAA, 0x34 } }
> 
>  [Guids]
>    gEfiRedfishClientPkgTokenSpaceGuid    = { 0x8c444dae, 0x728b, 0x48ee,
> { 0x9e, 0x19, 0x8f, 0x0a, 0x3d, 0x4e, 0x9c, 0xc8 } }
> +
> +[PcdsFixedAtBuild]
> +
> gEfiRedfishClientPkgTokenSpaceGuid.PcdMaxRedfishSchemaStringSize|32|
> UINT32|0x10000001
> +
> gEfiRedfishClientPkgTokenSpaceGuid.PcdMaxRedfishSchemaVersionSize|8|
> UINT32|0x10000002
> +  #
> +  # gEfiEventReadyToBootGuid is the default event to startup Redfish
> feature drivers.
> +  # { 0x7CE88FB3, 0x4BD7, 0x4679, { 0x87, 0xA8, 0xA8, 0xD8, 0xDE, 0xE5, 0x0D,
> 0x2B }}
> +  #
> +
> gEfiRedfishClientPkgTokenSpaceGuid.PcdEdkIIRedfishFeatureDriverStartupE
> ventGuid|{0xB3, 0x8F, 0xE8, 0x7C, 0xD7, 0x4B, 0x79, 0x46, 0x87, 0xA8, 0xA8,
> 0xD8, 0xDE, 0xE5, 0x0D, 0x2B}|VOID*|0x10000003
> +
> diff --git a/RedfishClientPkg/RedfishClientComponents.dsc.inc
> b/RedfishClientPkg/RedfishClientComponents.dsc.inc
> index 0648fa9d54..e4e2619bfb 100644
> --- a/RedfishClientPkg/RedfishClientComponents.dsc.inc
> +++ b/RedfishClientPkg/RedfishClientComponents.dsc.inc
> @@ -13,4 +13,6 @@
>  ##
> 
>  !if $(REDFISH_CLIENT) == TRUE
> +  RedfishClientPkg/RedfishFeatureCoreDxe/RedfishFeatureCoreDxe.inf
>  !endif
> +
> diff --git a/RedfishClientPkg/RedfishClient.fdf.inc
> b/RedfishClientPkg/RedfishClient.fdf.inc
> index 4f0714004e..d4c5874787 100644
> --- a/RedfishClientPkg/RedfishClient.fdf.inc
> +++ b/RedfishClientPkg/RedfishClient.fdf.inc
> @@ -11,4 +11,5 @@
>  #
>  ##
>  !if $(REDFISH_CLIENT) == TRUE
> +  INF RedfishClientPkg/RedfishFeatureCoreDxe/RedfishFeatureCoreDxe.inf
>  !endif
> diff --git
> a/RedfishClientPkg/RedfishFeatureCoreDxe/RedfishFeatureCoreDxe.inf
> b/RedfishClientPkg/RedfishFeatureCoreDxe/RedfishFeatureCoreDxe.inf
> new file mode 100644
> index 0000000000..5a2cd7fecc
> --- /dev/null
> +++ b/RedfishClientPkg/RedfishFeatureCoreDxe/RedfishFeatureCoreDxe.inf
> @@ -0,0 +1,49 @@
> +## @file
> +#  RedfishFeatureCoreDxe is the DXE driver which provides
> +#  EdkIIRedfishFeatureCoreProtocol to EDK2 Redfish Feature
> +#  drivers for the registration.
> +#
> +#  (C) Copyright 2021 Hewlett Packard Enterprise Development LP<BR>
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 0x0001000b
> +  BASE_NAME                      = RedfishFeatureCoreDxe
> +  FILE_GUID                      = 1E01A624-4161-F1F1-25BC-D28E77420D8E
> +  MODULE_TYPE                    = DXE_DRIVER
> +  VERSION_STRING                 = 1.0
> +  ENTRY_POINT                    = RedfishFeatureCoreEntryPoint
> +
> +#
> +#  VALID_ARCHITECTURES           = IA32 X64 ARM AARCH64 RISCV64
> +#
> +
> +[Sources]
> +  RedfishFeatureCoreDxe.c
> +  RedfishFeatureCoreDxe.h
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +  RedfishClientPkg/RedfishClientPkg.dec
> +
> +[LibraryClasses]
> +  BaseLib
> +  BaseMemoryLib
> +  DebugLib
> +  MemoryAllocationLib
> +  PrintLib
> +  UefiBootServicesTableLib
> +  UefiDriverEntryPoint
> +  UefiLib
> +
> +[Protocols]
> +  gEdkIIRedfishFeatureProtocolGuid    ## BY_START
> +
> +[Pcd]
> +
> gEfiRedfishClientPkgTokenSpaceGuid.PcdEdkIIRedfishFeatureDriverStartupE
> ventGuid
> +
> +[Depex]
> +  TRUE
> diff --git a/RedfishClientPkg/Include/Protocol/EdkIIRedfishFeature.h
> b/RedfishClientPkg/Include/Protocol/EdkIIRedfishFeature.h
> new file mode 100644
> index 0000000000..036622128d
> --- /dev/null
> +++ b/RedfishClientPkg/Include/Protocol/EdkIIRedfishFeature.h
> @@ -0,0 +1,116 @@
> +/** @file
> +  This file defines the EDKII_REDFISH_FEATURE_PROTOCOL interface.
> +
> +  (C) Copyright 2021 Hewlett Packard Enterprise Development LP<BR>
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#ifndef EDKII_REDFISH_FEATURE_H_
> +#define EDKII_REDFISH_FEATURE_H_
> +
> +typedef struct _EDKII_REDFISH_FEATURE_PROTOCOL
> EDKII_REDFISH_FEATURE_PROTOCOL;
> +
> +#define EDKII_REDFISH_FEATURE_PROTOCOL_GUID \
> +    {  \
> +      0x785CC694, 0x4930, 0xEFBF, { 0x2A, 0xCB, 0xA4, 0xB6, 0xA1, 0xCC, 0xAA,
> 0x34 }  \
> +    }
> +
> +typedef enum {
> +  CallbackActionNone = 0,       ///< Invalid action
> +  CallbackActionStartOperation, ///< Start the operations on Redfish
> resource
> +  CallbackActionMax
> +} FEATURE_CALLBACK_ACTION;
> +
> +typedef enum {
> +  InformationTypeNone = 0,            ///< Invalid information.
> +  InformationTypeCollectionMemberUri, ///< URI to the new created
> collection member.
> +  InformationTypeMax
> +} FEATURE_RETURNED_INFORMATION_TYPE;
> +
> +typedef struct {
> +  FEATURE_RETURNED_INFORMATION_TYPE Type;
> +} FEATURE_RETURNED_INFORMATION;
> +
> +/**
> +  The callback function provided by Redfish Feature driver.
> +
> +  @param[in]     This                Pointer to EDKII_REDFISH_FEATURE_PROTOCOL
> instance.
> +  @param[in]     FeatureAction       The action Redfish feature driver should
> take.
> +  @param[in]     Context             The context of Redfish feature driver.
> +  @param[in,out] InformationReturned The pointer to retrive the pointer to
> +                                     FEATURE_RETURNED_INFOMATION. The memory block
> of this
> +                                     information should be freed by caller.
> +
> +  @retval EFI_SUCCESS              Redfish feature driver callback is executed
> successfully.
> +  @retval Others                   Some errors happened.
> +
> +**/
> +typedef
> +EFI_STATUS
> +(EFIAPI *REDFISH_FEATURE_CALLBACK) (
> +  IN     EDKII_REDFISH_FEATURE_PROTOCOL *This,
> +  IN     FEATURE_CALLBACK_ACTION        FeatureAction,
> +  IN     VOID                           *Context,
> +  IN OUT FEATURE_RETURNED_INFORMATION   **InformationReturned
> +);
> +/**
> +  The registration function for the Redfish Feature driver.
> +
> +  @param[in]   This                Pointer to EDKII_REDFISH_FEATURE_PROTOCOL
> instance.
> +  @param[in]   FeatureManagedUri   The URI represents the hierarchy path
> of the Redfish
> +                                   resource in the entire Redfish data model that managed
> +                                   by Redfish feature driver . Each node in the hierarchy
> +                                   path is the property name defined in the schema of the
> +                                   resource.
> +  @param[in]   Callback            Callback routine associated with this
> registration that
> +                                   provided by Redfish feature driver to execute the action
> +                                   on Redfish resource which is managed by this Redfish
> +                                   feature driver.
> +  @param[in]   Context             The context of the registering feature driver.
> The pointer
> +                                   to the conext is delivered through callback function.
> +  @retval EFI_SUCCESS              Redfish feature driver is registered
> successfully.
> +  @retval Others                   Some error happened.
> +
> +**/
> +typedef
> +EFI_STATUS
> +(EFIAPI *REDFISH_FEATURE_REGISTER) (
> +  IN     EDKII_REDFISH_FEATURE_PROTOCOL  *This,
> +  IN     EFI_STRING                      FeatureManagedUri,
> +  IN     REDFISH_FEATURE_CALLBACK        Callback,
> +  IN     VOID                            *Context
> +);
> +
> +/**
> +  The unregistration function for the Redfish Feature driver.
> +
> +  @param[in]   This                Pointer to EDKII_REDFISH_FEATURE_PROTOCOL
> instance.
> +  @param[in]   FeatureManagedUri   The URI represents the hierarchy path
> of the Redfish
> +                                   resource in the entire Redfish data model that managed
> +                                   by Redfish feature driver . Each node in the hierarchy
> +                                   path is the property name defined in the schema of the
> +                                   resource.
> +  @param[in]   Context             The context used for the previous feature
> driver
> +                                   registration.
> +  @retval EFI_SUCCESS              Redfish feature driver is registered
> successfully.
> +  @retval Others                   Some error happened.
> +
> +**/
> +typedef
> +EFI_STATUS
> +(EFIAPI *REDFISH_FEATURE_UNREGISTER) (
> +  IN     EDKII_REDFISH_FEATURE_PROTOCOL  *This,
> +  IN     EFI_STRING                      FeatureManagedUri,
> +  IN     VOID                            *Context
> +);
> +
> +struct _EDKII_REDFISH_FEATURE_PROTOCOL {
> +  REDFISH_FEATURE_REGISTER      Register;
> +  REDFISH_FEATURE_UNREGISTER    Unregister;
> +};
> +
> +extern EFI_GUID gEdkIIRedfishFeatureProtocolGuid;
> +
> +#endif
> diff --git
> a/RedfishClientPkg/RedfishFeatureCoreDxe/RedfishFeatureCoreDxe.h
> b/RedfishClientPkg/RedfishFeatureCoreDxe/RedfishFeatureCoreDxe.h
> new file mode 100644
> index 0000000000..7b1778b038
> --- /dev/null
> +++ b/RedfishClientPkg/RedfishFeatureCoreDxe/RedfishFeatureCoreDxe.h
> @@ -0,0 +1,43 @@
> +/** @file
> +  Definitions of RedfishFeatureCoreDxe
> +
> +  (C) Copyright 2021 Hewlett Packard Enterprise Development LP<BR>
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +#ifndef EDKII_REDFISH_FEATURE_CORE_DXE_H_
> +#define EDKII_REDFISH_FEATURE_CORE_DXE_H_
> +
> +#include <Protocol/EdkIIRedfishFeature.h>
> +
> +#include <Base.h>
> +#include <Library/BaseLib.h>
> +#include <Library/BaseMemoryLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/MemoryAllocationLib.h>
> +#include <Library/PrintLib.h>
> +#include <Library/UefiBootServicesTableLib.h>
> +
> +#define MaxNodeNameLength 64
> +#define NodeSeperator L'/'
> +#define NodeIsCollectionLeftBracket '{'
> +#define NodeIsCollectionRightBracket '}'
> +
> +typedef struct _REDFISH_FEATURE_INTERNAL_DATA
> REDFISH_FEATURE_INTERNAL_DATA;
> +struct _REDFISH_FEATURE_INTERNAL_DATA {
> +  REDFISH_FEATURE_INTERNAL_DATA *SiblingList; ///< Next same level in
> hierarchy of resource URI.
> +  REDFISH_FEATURE_INTERNAL_DATA *ChildList;   ///< Next level in
> hierarchy of resource URI.
> +  EFI_STRING               NodeName;    ///< Name of the node in hierarchy of
> resource URI.
> +  REDFISH_FEATURE_CALLBACK Callback;    ///< Callback function of Redfish
> feature driver.
> +  VOID                     *Context;    ///< Context of feature driver.
> +  FEATURE_RETURNED_INFORMATION *ReturnedInformation; ///<
> Information returned from Redfish feature driver.
> +  UINT32         Flags;
> +};
> +#define REDFISH_FEATURE_INTERNAL_DATA_IS_COLLECTION 0x00000001
> +
> +typedef struct {
> +  EDKII_REDFISH_FEATURE_PROTOCOL *This;
> +  FEATURE_CALLBACK_ACTION Action;
> +} REDFISH_FEATURE_STARTUP_CONTEXT;
> +#endif
> diff --git
> a/RedfishClientPkg/RedfishFeatureCoreDxe/RedfishFeatureCoreDxe.c
> b/RedfishClientPkg/RedfishFeatureCoreDxe/RedfishFeatureCoreDxe.c
> new file mode 100644
> index 0000000000..e5dcc3de8e
> --- /dev/null
> +++ b/RedfishClientPkg/RedfishFeatureCoreDxe/RedfishFeatureCoreDxe.c
> @@ -0,0 +1,382 @@
> +/** @file
> +  RedfishFeatureCoreDxe produces EdkIIRedfishFeatureCoreProtocol
> +  for EDK2 Redfish Feature driver registration.
> +
> +  (C) Copyright 2021 Hewlett Packard Enterprise Development LP<BR>
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <RedfishFeatureCoreDxe.h>
> +
> +EFI_EVENT mEdkIIRedfishFeatureDriverStartupEvent;
> +REDFISH_FEATURE_STARTUP_CONTEXT mFeatureDriverStartupContext;
> +REDFISH_FEATURE_INTERNAL_DATA *ResourceUriNodeList;
> +
> +/**
> +  Startup child feature drivers and it's sibing feature drivers.
> +
> +  @param[in]  HeadList              Head list of this feature driver
> +  @param[in]  ThisFeatureDriverList This feature driver list.
> +  @param[in]  StartupContext        Start up information
> +
> +**/
> 
> Function header mismatch here. HeadList is not a function parameter as
> below.
> 
> +VOID
> +StartUpFeatureDriver (
> +  IN REDFISH_FEATURE_INTERNAL_DATA *ThisFeatureDriverList,
> +  IN REDFISH_FEATURE_STARTUP_CONTEXT *StartupContext
> +)
> +{
> +  EFI_STATUS Status;
> +  REDFISH_FEATURE_INTERNAL_DATA *ThisList;
> +
> +  ThisList = ThisFeatureDriverList;
> +  while (TRUE) {
> +    if (ThisList->Callback != NULL) {
> +      Status = ThisList->Callback(
> +                           StartupContext->This,
> +                           StartupContext->Action,
> +                           ThisList->Context,
> +                           &ThisList->ReturnedInformation
> +                           );
> +      if (EFI_ERROR (Status)) {
> +        DEBUG((DEBUG_ERROR, "%a: Callback to EDK2 Redfish feature driver
> fail.", __FUNCTION__));
> +      }
> +    }
> +    if (ThisList->ChildList != NULL) {
> +      StartUpFeatureDriver (ThisList->ChildList, StartupContext);
> +    }
> +    //
> +    // Check sibling Redfish feature driver.
> +    //
> +    if (ThisList->SiblingList == NULL) {
> +      break;
> +    }
> +    //
> +    // Go next sibling Redfish feature driver.
> +    //
> +    ThisList = ThisList->SiblingList;
> +  };
> +}
> +
> +/**
> +  Callback routine when mEdkIIRedfishFeatureDriverStartupEvent
> +  is signaled.
> +
> +  @param[in]  Event                 Event whose notification function is being
> invoked.
> +  @param[in]  Context               The pointer to the notification function's
> context,
> +                                    which is implementation-dependent.
> +
> +**/
> +VOID
> +RedfishFeatureDriverStartup(
> +  IN  EFI_EVENT                Event,
> +  IN  VOID                     *Context
> +  )
> +{
> +  REDFISH_FEATURE_STARTUP_CONTEXT *StartupContext;
> +
> +  StartupContext = (REDFISH_FEATURE_STARTUP_CONTEXT *)Context;
> +  //
> +  // Invoke EDK2 Redfish feature driver callback to start up
> +  // the Redfish operations.
> +  //
> +  if (ResourceUriNodeList == NULL) {
> +    return;
> +  }
> +  //
> +  // Invoke the callback by the hierarchy level
> +  //
> +  StartUpFeatureDriver (ResourceUriNodeList, StartupContext);
> +}
> +
> +/**
> +  Create new internal data instance.
> +
> +  @param[in,out] PtrToNewInternalData  Pointer to receive new instance of
> +                                       REDFISH_FEATURE_INTERNAL_DATA.
> +  @param[in]     NodeName              Name of URI node.
> +
> +  @retval EFI_SUCCESS              New entry is inserted successfully.
> +  @retval EFI_INVALID_PARAMETER    Improper given parameters.
> +  @retval EFI_OUT_OF_RESOURCES     Lack of memory for the internal data
> structure.
> +
> +**/
> +EFI_STATUS
> +NewInternalInstance (
> +  IN OUT REDFISH_FEATURE_INTERNAL_DATA **PtrToNewInternalData,
> +  IN EFI_STRING NodeName
> +  )
> +{
> +  REDFISH_FEATURE_INTERNAL_DATA *NewInternalData;
> +
> +  if (PtrToNewInternalData == NULL || NodeName == NULL) {
> +    DEBUG((DEBUG_ERROR, "%a: Inproper given parameters\n",
> __FUNCTION__));
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  *PtrToNewInternalData = NULL;
> +  NewInternalData = AllocateZeroPool (sizeof
> (REDFISH_FEATURE_INTERNAL_DATA));
> +  if (NewInternalData == NULL) {
> +    DEBUG((DEBUG_ERROR, "%a: No memory for
> REDFISH_FEATURE_INTERNAL_DATA\n", __FUNCTION__));
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +  NewInternalData->NodeName = AllocateZeroPool (StrSize (NodeName));
> +  StrnCpyS (NewInternalData->NodeName, StrSize (NodeName), (CONST
> CHAR16 *)NodeName, StrLen (NodeName));
> +  NewInternalData->SiblingList = NULL;
> +  NewInternalData->ChildList = NULL;
> +  if (NodeName[0] == (UINT16)NodeIsCollectionLeftBracket &&
> +      NodeName [StrLen (NodeName) - 1] ==
> (UINT16)NodeIsCollectionRightBracket) {
> +    NewInternalData->Flags |=
> REDFISH_FEATURE_INTERNAL_DATA_IS_COLLECTION;
> +  }
> +  *PtrToNewInternalData = NewInternalData;
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Insert the URI node into internal data structure
> +
> +  @param[in]   HeadEntryToInsert  The head entry to start the searching.
> +  @param[in]   NodeName           Name of URI node.
> +  @param[in]   NextNodeEntry      Pointer to receive the pointer of next
> head
> +                                  entry for inserting the follow up nodes.
> +                                  The returned LIST_ENTRY is the address of
> +                                  ChildList link list.
> 
> This is [in, out] according to below function header.
> 
> +  @retval EFI_SUCCESS              New entry is inserted successfully.
> +  @retval EFI_INVALID_PARAMETER    Improper given parameters.
> +  @retval EFI_OUT_OF_RESOURCES     Lack of memory for the internal data
> structure.
> +
> +**/
> +EFI_STATUS
> +InsertRedfishFeatureUriNode (
> +  IN REDFISH_FEATURE_INTERNAL_DATA      *HeadEntryToInsert,
> +  IN EFI_STRING                         NodeName,
> +  IN OUT REDFISH_FEATURE_INTERNAL_DATA  **NextNodeEntry
> +  )
> +{
> +  EFI_STATUS Status;
> +  REDFISH_FEATURE_INTERNAL_DATA *NewInternalData;
> +  REDFISH_FEATURE_INTERNAL_DATA *ThisInternalData;
> +  REDFISH_FEATURE_INTERNAL_DATA *SiblingList;
> +
> +  if (NodeName == NULL) {
> +    DEBUG((DEBUG_ERROR, "%a: Node name is NULL.\n", __FUNCTION__));
> +    return EFI_INVALID_PARAMETER;
> +  }
> +  if (NextNodeEntry == NULL) {
> +    DEBUG((DEBUG_ERROR, "%a: NextNodeEntry can't be NULL.\n",
> __FUNCTION__));
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (HeadEntryToInsert == NULL || HeadEntryToInsert->ChildList == NULL) {
> +    Status = NewInternalInstance (&NewInternalData, NodeName);
> +    if (EFI_ERROR (Status)) {
> +      return Status;
> +    }
> +    if (HeadEntryToInsert == NULL) {
> +      ResourceUriNodeList = NewInternalData;
> +    } else {
> +      HeadEntryToInsert->ChildList = NewInternalData;
> +    }
> +    *NextNodeEntry = NewInternalData;
> +    return EFI_SUCCESS;
> +  }
> +  //
> +  // Go through sibling list to find the entry.
> +  //
> +  ThisInternalData = HeadEntryToInsert;
> +  SiblingList = ThisInternalData->SiblingList;
> +  while (TRUE) {
> +    if (StrCmp((CONST CHAR16 *)ThisInternalData->NodeName, (CONST
> CHAR16 *)NodeName) == 0) {
> +      *NextNodeEntry = ThisInternalData->ChildList;
> +      return EFI_SUCCESS;
> +    }
> +    //
> +    // If sibing exist?
> +    //
> +    if (SiblingList == NULL) {
> +      Status = NewInternalInstance (&NewInternalData, NodeName);
> +      if (EFI_ERROR (Status)) {
> +        return Status;
> +      }
> +      ThisInternalData->SiblingList = NewInternalData;
> +      *NextNodeEntry = NewInternalData->ChildList;
> +      return EFI_SUCCESS;
> +    }
> +    SiblingList = SiblingList->SiblingList;
> +  };
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  The registration function for the Redfish Feature driver.
> +
> +  @param[in]   This                Pointer to EDKII_REDFISH_FEATURE_PROTOCOL
> instance.
> +  @param[in]   FeatureManagedUri   The URI represents the hierarchy path
> of the Redfish
> +                                   resource in the entire Redfish data model that managed
> +                                   by Redfish feature driver . Each node in the hierarchy
> +                                   path is the property name defined in the schema of the
> +                                   resource.
> +                                   e.g. "ServiceRoot/" - Managed by ServiceRoot feature
> driver
> +                                        "ServiceRoot/Systems[]/" - Managed by
> ComputerSystemCollection feature driver
> +                                        "ServiceRoot/Systems[1]/" - Managed by
> ComputerSystem feature driver
> +                                        "ServiceRoot/Systems[2]/Bios/" - Managed by Bios
> feature driver
> +  @param[in]   Callback            Callback routine associated with this
> registration that
> +                                   provided by Redfish feature driver to execute the action
> +                                   on Redfish resource which is managed by this Redfish
> +                                   feature driver.
> +  @param[in]   Context             The context of the registering feature driver.
> The pointer
> +                                   to the conext is delivered through callback function.
> +  @retval EFI_SUCCESS              Redfish feature driver is registered
> successfully.
> +  @retval EFI_SUCCESS              Redfish feature driver is registered
> successfully.
> +  @retval EFI_INVALID_PARAMETER    Improper given parameters or fail to
> register
> +                                   feature driver.
> +  @retval EFI_OUT_OF_RESOURCES     Lack of memory for the internal data
> structure.
> +  @retval Others                   Some error happened.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +RedfishFeatureRegister (
> +  IN EDKII_REDFISH_FEATURE_PROTOCOL  *This,
> +  IN EFI_STRING                      FeatureManagedUri,
> +  IN REDFISH_FEATURE_CALLBACK        Callback,
> +  IN VOID                            *Context
> +)
> +{
> +  CHAR16 NodeName [MaxNodeNameLength];
> +  EFI_STATUS Status;
> +  UINTN Index;
> +  UINTN AnchorIndex;
> +  UINTN UriLength;
> +  REDFISH_FEATURE_INTERNAL_DATA *ThisUriNode;
> +
> +  if (FeatureManagedUri == NULL || Callback == NULL) {
> +    DEBUG((DEBUG_ERROR, "%a: The given parameter is invalid\n",
> __FUNCTION__));
> +    return EFI_INVALID_PARAMETER;
> +  }
> +  //
> +  // Walk through URI which managed by this EDK2 Redfish feature driver.
> +  //
> +  UriLength = StrLen (FeatureManagedUri) + 1; // Add one NULL for the last
> node.
> +  Index = 0;
> +  AnchorIndex = 0;
> +  ThisUriNode = ResourceUriNodeList;
> +  do {
> +    if ((Index - AnchorIndex + 1) >= MaxNodeNameLength) { // Increase one
> for the NULL terminator
> +      DEBUG((DEBUG_ERROR, "%a: the length of node name is >=
> MaxNodeNameLength\n", __FUNCTION__));
> +      ASSERT (FALSE);
> +    }
> +    NodeName[Index - AnchorIndex] = *(FeatureManagedUri + Index);
> +    if (NodeName [Index - AnchorIndex] == NodeSeperator || NodeName
> [Index - AnchorIndex] == (CHAR16)0) {
> +      NodeName [Index - AnchorIndex] = 0;
> +      AnchorIndex = Index + 1;
> +      //
> +      // Insert node
> +      //
> +      if (StrLen(NodeName) != 0) {
> +        Status = InsertRedfishFeatureUriNode(ThisUriNode, NodeName,
> &ThisUriNode);
> +        if (EFI_ERROR (Status)) {
> +          return Status;
> +        }
> +      }
> +    }
> +    Index ++;
> +  } while ((Index < UriLength));
> +
> +  if (ThisUriNode == NULL) {
> +    //
> +    // No URI node was created
> +    //
> +    DEBUG((DEBUG_ERROR, "%a: No URI node is added\n",
> __FUNCTION__));
> +    return EFI_INVALID_PARAMETER;
> +  }
> +  //
> +  // Add feature driver info to internal data instance.
> +  //
> +  ThisUriNode->Callback = Callback;
> +  ThisUriNode->Context = Context;
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  The unregistration function for the Redfish Feature driver.
> +
> +  @param[in]   This                Pointer to EDKII_REDFISH_FEATURE_PROTOCOL
> instance.
> +  @param[in]   FeatureManagedUri   The URI represents the hierarchy path
> of the Redfish
> +                                   resource in the entire Redfish data model that managed
> +                                   by Redfish feature driver . Each node in the hierarchy
> +                                   path is the property name defined in the schema of the
> +                                   resource.
> +  @param[in]   Context             The context used for the previous feature
> driver
> +                                   registration.
> +  @retval EFI_SUCCESS              Redfish feature driver is registered
> successfully.
> +  @retval Others                   Some error happened.
> +
> +**/
> +EFI_STATUS
> +RedfishFeatureUnregister (
> +  IN     EDKII_REDFISH_FEATURE_PROTOCOL  *This,
> +  IN     EFI_STRING                      FeatureManagedUri,
> +  IN     VOID                            *Context
> +)
> +{
> +  return EFI_UNSUPPORTED;
> +}
> +
> +EDKII_REDFISH_FEATURE_PROTOCOL mRedfishFeatureProtocol = {
> +  RedfishFeatureRegister,
> +  RedfishFeatureUnregister
> +};
> +
> +/**
> +  Main entry for this driver.
> +
> +  @param ImageHandle     Image handle this driver.
> +  @param SystemTable     Pointer to SystemTable.
> +
> 
> @param[in] for above two paramters
> 
> +  @retval EFI_SUCESS     This function always complete successfully.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +RedfishFeatureCoreEntryPoint (
> +  IN EFI_HANDLE         ImageHandle,
> +  IN EFI_SYSTEM_TABLE   *SystemTable
> +  )
> +{
> +  EFI_STATUS  Status;
> +  EFI_HANDLE  Handle;
> +  EFI_GUID *EventGuid;
> +
> +  Handle = NULL;
> +  ResourceUriNodeList = NULL;
> +  EventGuid = (EFI_GUID *)PcdGetPtr
> (PcdEdkIIRedfishFeatureDriverStartupEventGuid);
> +
> +  ZeroMem ((VOID *)&mFeatureDriverStartupContext, sizeof
> (REDFISH_FEATURE_STARTUP_CONTEXT));
> +  mFeatureDriverStartupContext.This = &mRedfishFeatureProtocol;
> +
> +  Status = gBS->CreateEventEx (
> +                EVT_NOTIFY_SIGNAL,
> +                TPL_CALLBACK,
> +                RedfishFeatureDriverStartup,
> +                (CONST VOID *)&mFeatureDriverStartupContext,
> +                EventGuid,
> +                &mEdkIIRedfishFeatureDriverStartupEvent
> +                );
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  //
> +  // Install the RedfishCredentialProtocol onto Handle.
> +  //
> +  Status = gBS->InstallMultipleProtocolInterfaces (
> +                  &Handle,
> +                  &gEdkIIRedfishFeatureProtocolGuid,
> +                  &mRedfishFeatureProtocol,
> +                  NULL
> +                  );
> +  return Status;
> +}
> diff --git a/RedfishClientPkg/Readme.md b/RedfishClientPkg/Readme.md
> index 9e56fb9039..18a27633cf 100644
> --- a/RedfishClientPkg/Readme.md
> +++ b/RedfishClientPkg/Readme.md
> @@ -119,6 +119,42 @@ struct
> _EDKII_REDFISH_PLATFORM_CONFIG_PROTOCOL {
>  For those Non-EDK2 HII-based platform configuration formats, the driver
> instance
>  can provide its own implementation to get or set the platform configurations.
> 
> +### EDKII Redfish Feature Core DXE Driver ***[[12]](#[0])***
> +EDKII Redfish Feature Core DXE driver provides the protocol interface to
> +the auto-generated Redfish feature driver to register itself for the
> +Redfish resource URI it manages.
> +
> +```C
> +struct _EDKII_REDFISH_FEATURE_PROTOCOL {
> +  REDFISH_FEATURE_REGISTER      Register;
> +  REDFISH_FEATURE_UNREGISTER    Unregister;
> +};
> +```
> +
> +Redfish Feature Core DXE driver records the
> +URI according to the URI hierarchy, and then it starts up the Redfish
> +feature drivers based on the hierarchy when the particular event
> +***[[11]](#[0])*** is triggered. This makes sure the upper-level Redfish
> +resource is built up before the lower-level resource. For example,
> +ComputerSystem resource must be ready before the Memory resource
> managed
> +by MemoryCollection because the Memory resource is part of
> ComputerSystem
> +resource.
> +
> +### Start-Up Event to Trigger EDKII Redfish Feature Core
> ***[[11]](#[0])***
> +This is an EFI event for triggering EDKII Redfish Feature Core to travel
> +URIs in the database and execute the callback that registered by Redfish
> feature
> +drivers. The event GUID is defined in below PCD and is default set to
> +**gEfiEventReadyToBootGuid**.
> +
> +```C
> +PcdEdkIIRedfishFeatureDriverStartupEventGuid
> +```
> +
> +This PCD can be overridden to any events based on the platform
> +implementation. EDKII Redfish Feature Core can be triggered earlier,
> +for example before the BDS or in the early DXE phase if the platform
> provides
> +the EFI REST EX protocol which is available before the BDS phase.
> +
>  ### EDK2 HII VFR Form ***[[8]](#[0])***
>  According to **UEFI spec 2.9 section 35.6 Form Browser Protocol**,
>  **EFI_HII_REST_STYLE_FORMSET_GUID** is used on HII form to indicate
> that HII
> --
> 2.17.1