Re: [PATCH 4/4] DynamicTablesPkg: AcpiSsdtPcieLibArm: Add support for override protocol

["PierreGondois" <pierre.gondois@arm.com>]

Hello Jeff,
Is it possible to know what the UpdateTable() function would do ?
Maybe it would be possible to integrate the alternative
implementation without adding a new protocol.

Regards,
Pierre

On 6/30/22 17:48, Jeff Brasen wrote:
> Some platfoms may want to modify the ACPI table created.
> Add support for protocol that can provide an alternative implementation.
> 
> Signed-off-by: Jeff Brasen <jbrasen@nvidia.com>
> ---
>   DynamicTablesPkg/DynamicTablesPkg.dec         |  3 +
>   .../Protocol/SsdtPcieOverrideProtocol.h       | 63 +++++++++++++++++++
>   .../AcpiSsdtPcieLibArm/SsdtPcieGenerator.c    | 31 ++++++++-
>   .../Arm/AcpiSsdtPcieLibArm/SsdtPcieLibArm.inf |  4 ++
>   4 files changed, 98 insertions(+), 3 deletions(-)
>   create mode 100644 DynamicTablesPkg/Include/Protocol/SsdtPcieOverrideProtocol.h
> 
> diff --git a/DynamicTablesPkg/DynamicTablesPkg.dec b/DynamicTablesPkg/DynamicTablesPkg.dec
> index a890a048be..bb66bdaf14 100644
> --- a/DynamicTablesPkg/DynamicTablesPkg.dec
> +++ b/DynamicTablesPkg/DynamicTablesPkg.dec
> @@ -43,6 +43,9 @@
>     # Dynamic Table Factory Protocol GUID
>     gEdkiiDynamicTableFactoryProtocolGuid = { 0x91d1e327, 0xfe5a, 0x49b8, { 0xab, 0x65, 0xe, 0xce, 0x2d, 0xdb, 0x45, 0xec } }
>   
> +  # Protocol to override PCI SSDT table generation
> +  gEdkiiDynamicTableSsdtPcieOverrideProtocolGuid = { 0x962e8b44, 0x23b3, 0x41da, { 0x9f, 0x36, 0xca, 0xde, 0x68, 0x49, 0xfb, 0xf6 } }
> +
>   [PcdsFixedAtBuild]
>   
>     # Maximum number of Custom ACPI Generators
> diff --git a/DynamicTablesPkg/Include/Protocol/SsdtPcieOverrideProtocol.h b/DynamicTablesPkg/Include/Protocol/SsdtPcieOverrideProtocol.h
> new file mode 100644
> index 0000000000..29568a0159
> --- /dev/null
> +++ b/DynamicTablesPkg/Include/Protocol/SsdtPcieOverrideProtocol.h
> @@ -0,0 +1,63 @@
> +/** @file
> +
> +  Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#ifndef SSDT_PCIE_OVERRIDE_PROTOCOL_H_
> +#define SSDT_PCIE_OVERRIDE_PROTOCOL_H_
> +
> +#include <ArmNameSpaceObjects.h>
> +#include <Library/AmlLib/AmlLib.h>
> +
> +/** This macro defines the SSDT PCI Override Protocol GUID.
> +
> +  GUID: {D85A4835-5A82-4894-AC02-706F43D5978E}
> +*/
> +#define EDKII_SSDT_PCI_OVERRIDE_PROTOCOL_GUID           \
> +  { 0x962e8b44, 0x23b3, 0x41da,                         \
> +    { 0x9f, 0x36, 0xca, 0xde, 0x68, 0x49, 0xfb, 0xf6 }  \
> +  };
> +
> +/**
> +  Forward declarations:
> +*/
> +typedef struct SsdtOverridePciProtocol EDKII_SSDT_PCI_OVERRIDE_PROTOCOL;
> +
> +/** The UpdateTable function allows the override protocol to update the
> + *   PCIe SSDT table prior to being created.
> +
> +  @param [in]      This    Pointer to the SSDT PCI Override Protocol.
> +  @param [in]      PciInfo The PCIe configuration info for this node.
> +  @param [in]      Uid     UID that was selected for this PCIe node.
> +  @param [in, out] PciNode Pointer to the PCI node of this ACPI table.
> +
> +  @retval EFI_SUCCESS           Success.
> +  @retval EFI_INVALID_PARAMETER A parameter is invalid.
> +  @retval EFI_DEVICE_ERROR      Failed to update the table.
> +**/
> +typedef
> +EFI_STATUS
> +(EFIAPI *EDKII_SSDT_PCI_OVERRIDE_PROTOCOL_UPDATE_TABLE)(
> +  IN      CONST EDKII_SSDT_PCI_OVERRIDE_PROTOCOL  *CONST  This,
> +  IN      CONST CM_ARM_PCI_CONFIG_SPACE_INFO              *PciInfo,
> +  IN            UINT32                                    Uid,
> +  IN  OUT       AML_ROOT_NODE_HANDLE                      *PciNode
> +  );
> +
> +/** The EDKII_CONFIGURATION_MANAGER_PROTOCOL structure describes the
> +    Configuration Manager Protocol interface.
> +*/
> +typedef struct SsdtOverridePciProtocol {
> +  /** The interface used to update the ACPI table for PCI.
> +  */
> +  EDKII_SSDT_PCI_OVERRIDE_PROTOCOL_UPDATE_TABLE    UpdateTable;
> +} EDKII_SSDT_PCI_OVERRIDE_PROTOCOL;
> +
> +/** The SSDT PCI Override Protocol GUID.
> +*/
> +extern EFI_GUID  gEdkiiDynamicTableSsdtPcieOverrideProtocolGuid;
> +
> +#endif // SSDT_PCIE_OVERRIDE_PROTOCOL_H_
> diff --git a/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieGenerator.c b/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieGenerator.c
> index c5b23d91d0..d5982c24ff 100644
> --- a/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieGenerator.c
> +++ b/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieGenerator.c
> @@ -20,6 +20,7 @@
>   #include <Library/BaseMemoryLib.h>
>   #include <Library/DebugLib.h>
>   #include <Library/MemoryAllocationLib.h>
> +#include <Library/UefiBootServicesTableLib.h>
>   #include <Protocol/AcpiTable.h>
>   
>   // Module specific include files.
> @@ -30,6 +31,7 @@
>   #include <Library/TableHelperLib.h>
>   #include <Library/AmlLib/AmlLib.h>
>   #include <Protocol/ConfigurationManagerProtocol.h>
> +#include <Protocol/SsdtPcieOverrideProtocol.h>
>   
>   #include "SsdtPcieGenerator.h"
>   
> @@ -798,9 +800,10 @@ GeneratePciDevice (
>   {
>     EFI_STATUS  Status;
>   
> -  CHAR8                   AslName[AML_NAME_SEG_SIZE + 1];
> -  AML_OBJECT_NODE_HANDLE  ScopeNode;
> -  AML_OBJECT_NODE_HANDLE  PciNode;
> +  CHAR8                             AslName[AML_NAME_SEG_SIZE + 1];
> +  AML_OBJECT_NODE_HANDLE            ScopeNode;
> +  AML_OBJECT_NODE_HANDLE            PciNode;
> +  EDKII_SSDT_PCI_OVERRIDE_PROTOCOL  *OverrideProtocol;
>   
>     ASSERT (Generator != NULL);
>     ASSERT (CfgMgrProtocol != NULL);
> @@ -860,6 +863,28 @@ GeneratePciDevice (
>   
>     // Add the template _OSC method.
>     Status = AddOscMethod (PciNode);
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    return Status;
> +  }
> +
> +  Status = gBS->LocateProtocol (
> +                  &gEdkiiDynamicTableSsdtPcieOverrideProtocolGuid,
> +                  NULL,
> +                  (VOID **)&OverrideProtocol
> +                  );
> +  if (!EFI_ERROR (Status)) {
> +    Status = OverrideProtocol->UpdateTable (
> +                                 OverrideProtocol,
> +                                 PciInfo,
> +                                 Uid,
> +                                 PciNode
> +                                 );
> +  } else {
> +    // Not an error if override protocol is not found
> +    Status = EFI_SUCCESS;
> +  }
> +
>     ASSERT_EFI_ERROR (Status);
>     return Status;
>   }
> diff --git a/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieLibArm.inf b/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieLibArm.inf
> index 431e32a777..8e916f15e9 100644
> --- a/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieLibArm.inf
> +++ b/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieLibArm.inf
> @@ -30,6 +30,10 @@
>     AcpiHelperLib
>     AmlLib
>     BaseLib
> +  UefiBootServicesTableLib
>   
>   [Pcd]
>     gEdkiiDynamicTablesPkgTokenSpaceGuid.PcdPciUseSegmentAsUid
> +
> +[Protocols]
> +  gEdkiiDynamicTableSsdtPcieOverrideProtocolGuid