Re: [PATCH 2/4] DynamicTablesPkg: AcpiSsdtPcieLibArm: Allow use of segment number as UID

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

Hello Jeff,

 From "PCI Firmware Specification Revision 3.3", s4.1.2.
"MCFG Table Description", the "PCI Segment Group Number" field of the
MCFG table must match the value returned by the _SEG object in the
corresponding object.

I didn't find any constraint about the _UID value. Would it be possible
to know why this is required ?

Regards,
Pierre

On 6/30/22 17:48, Jeff Brasen wrote:
> Add support for selecting to use index or segment number as UID and name.
> This allows the path of the nodes to be well known.
> 
> Signed-off-by: Jeff Brasen <jbrasen@nvidia.com>
> ---
>   DynamicTablesPkg/DynamicTablesPkg.dec         |  3 +++
>   .../AcpiSsdtPcieLibArm/SsdtPcieGenerator.c    | 19 ++++++++++++++++++-
>   .../Arm/AcpiSsdtPcieLibArm/SsdtPcieLibArm.inf |  3 +++
>   3 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/DynamicTablesPkg/DynamicTablesPkg.dec b/DynamicTablesPkg/DynamicTablesPkg.dec
> index 9b74c5a671..a890a048be 100644
> --- a/DynamicTablesPkg/DynamicTablesPkg.dec
> +++ b/DynamicTablesPkg/DynamicTablesPkg.dec
> @@ -57,5 +57,8 @@
>     # Non BSA Compliant 16550 Serial HID
>     gEdkiiDynamicTablesPkgTokenSpaceGuid.PcdNonBsaCompliant16550SerialHid|""|VOID*|0x40000008
>   
> +  # Use PCI segment numbers as UID
> +  gEdkiiDynamicTablesPkgTokenSpaceGuid.PcdPciUseSegmentAsUid|FALSE|BOOLEAN|0x40000009
> +
>   [Guids]
>     gEdkiiDynamicTablesPkgTokenSpaceGuid = { 0xab226e66, 0x31d8, 0x4613, { 0x87, 0x9d, 0xd2, 0xfa, 0xb6, 0x10, 0x26, 0x3c } }
> diff --git a/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieGenerator.c b/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieGenerator.c
> index f0d15f69a4..85782af380 100644
> --- a/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieGenerator.c
> +++ b/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieGenerator.c
> @@ -996,6 +996,7 @@ BuildSsdtPciTableEx (
>     UINTN                         Index;
>     EFI_ACPI_DESCRIPTION_HEADER   **TableList;
>     ACPI_PCI_GENERATOR            *Generator;
> +  UINT32                        Uid;
>   
>     ASSERT (This != NULL);
>     ASSERT (AcpiTableInfo != NULL);
> @@ -1051,13 +1052,29 @@ BuildSsdtPciTableEx (
>     *Table = TableList;
>   
>     for (Index = 0; Index < PciCount; Index++) {
> +    if (PcdGetBool (PcdPciUseSegmentAsUid)) {
> +      Uid = PciInfo[Index].PciSegmentGroupNumber;
> +      if (Uid > MAX_PCI_ROOT_COMPLEXES_SUPPORTED) {
> +        DEBUG ((
> +          DEBUG_ERROR,
> +          "ERROR: SSDT-PCI: Pci root complexes segment number: %d."
> +          " Greater than maximum number of Pci root complexes supported = %d.\n",
> +          Uid,
> +          MAX_PCI_ROOT_COMPLEXES_SUPPORTED
> +          ));
> +        return EFI_INVALID_PARAMETER;
> +      }
> +    } else {
> +      Uid = Index;
> +    }
> +
>       // Build a SSDT table describing the Pci devices.
>       Status = BuildSsdtPciTable (
>                  Generator,
>                  CfgMgrProtocol,
>                  AcpiTableInfo,
>                  &PciInfo[Index],
> -               Index,
> +               Uid,
>                  &TableList[Index]
>                  );
>       if (EFI_ERROR (Status)) {
> diff --git a/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieLibArm.inf b/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieLibArm.inf
> index 283b564801..431e32a777 100644
> --- a/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieLibArm.inf
> +++ b/DynamicTablesPkg/Library/Acpi/Arm/AcpiSsdtPcieLibArm/SsdtPcieLibArm.inf
> @@ -30,3 +30,6 @@
>     AcpiHelperLib
>     AmlLib
>     BaseLib
> +
> +[Pcd]
> +  gEdkiiDynamicTablesPkgTokenSpaceGuid.PcdPciUseSegmentAsUid