From 475ed476ac6bbdb775acdd7c15b3dea1b98f76f8 Mon Sep 17 00:00:00 2001
From: Pierre Gondois <pierre.gondois@arm.com>
Date: Mon, 27 Jul 2026 15:55:24 +0200
Subject: [PATCH] DynamicTablesPkg: Add support for _STA in SSDT topology
 tables

Make use of the previously introduced StaToken field to
generate a _STA method describing the status of a processor
or processor container.
staSupp

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
---
 .../SsdtCpuTopologyGenerator.c                | 98 +++++++++++++++++++
 1 file changed, 98 insertions(+)

diff --git a/DynamicTablesPkg/Library/Acpi/Common/AcpiSsdtCpuTopologyLib/SsdtCpuTopologyGenerator.c b/DynamicTablesPkg/Library/Acpi/Common/AcpiSsdtCpuTopologyLib/SsdtCpuTopologyGenerator.c
index 311010b977..14b593586e 100644
--- a/DynamicTablesPkg/Library/Acpi/Common/AcpiSsdtCpuTopologyLib/SsdtCpuTopologyGenerator.c
+++ b/DynamicTablesPkg/Library/Acpi/Common/AcpiSsdtCpuTopologyLib/SsdtCpuTopologyGenerator.c
@@ -45,6 +45,7 @@ Requirements:
   - EArchCommonObjCmRef (OPTIONAL)
   - EArchCommonObjLpiInfo (OPTIONAL)
   - EArchCommonObjPsdInfo (OPTIONAL)
+  - EArchCommonObjStaInfo (OPTIONAL)
 */
 
 /**
@@ -97,6 +98,15 @@ GET_OBJECT_LIST (
   CM_ARCH_COMMON_PSD_INFO
   );
 
+/** This macro expands to a function that retrieves the
+    _STA (Device Status) information from the Configuration Manager.
+*/
+GET_OBJECT_LIST (
+  EObjNameSpaceArchCommon,
+  EArchCommonObjStaInfo,
+  CM_ARCH_COMMON_STA_INFO
+  );
+
 /** Initialize the TokenTable.
 
   One entry should be allocated for each CM_ARCH_COMMON_PROC_HIERARCHY_INFO
@@ -696,6 +706,68 @@ CreateAmlCpu (
   return Status;
 }
 
+/** Create a "_STA" method and attach it to the parent node.
+
+  The function generate the following ASL code:
+  Method (_STA, 0, NotSerialized)  // _STA: Status
+  {
+      Return (0xXX)
+  }
+
+  @param [in]  Generator              The SSDT Cpu Topology generator.
+  @param [in]  CfgMgrProtocol         Pointer to the Configuration Manager
+                                      Protocol Interface.
+  @param [in]  StaToken               Token referencing a CM_ARCH_COMMON_STA_INFO obj.
+  @param [in]  ParentNode             Parent node to attach the "_STA" method to.
+
+  @retval EFI_SUCCESS             Success.
+  @retval EFI_INVALID_PARAMETER   Invalid parameter.
+  @retval EFI_OUT_OF_RESOURCES    Failed to allocate memory.
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+CreateAmlStatus (
+  IN        ACPI_CPU_TOPOLOGY_GENERATOR                   *Generator,
+  IN  CONST EDKII_CONFIGURATION_MANAGER_PROTOCOL  *CONST  CfgMgrProtocol,
+  IN        CM_OBJECT_TOKEN                               StaToken,
+  IN        AML_NODE_HANDLE                               ParentNode
+  )
+{
+  EFI_STATUS               Status;
+  CM_ARCH_COMMON_STA_INFO  *StaInfo;
+
+  ASSERT (Generator != NULL);
+  ASSERT (CfgMgrProtocol != NULL);
+  ASSERT (ParentNode != NULL);
+  ASSERT (StaToken != CM_NULL_TOKEN);
+
+  Status = GetEArchCommonObjStaInfo (
+             CfgMgrProtocol,
+             StaToken,
+             &StaInfo,
+             NULL
+             );
+  if (EFI_ERROR (Status)) {
+    ASSERT_EFI_ERROR (Status);
+    return Status;
+  }
+
+  /// check STA bits
+  if ((StaInfo->DeviceStatus & ~(ACPI_AML_STA_BASE_SUPPORTED)) != 0) {
+    ASSERT (FALSE);
+    return EFI_UNSUPPORTED;
+  }
+
+  Status = AmlCodeGenMethodRetInteger ("_STA", StaInfo->DeviceStatus, 0, FALSE, 0, ParentNode, NULL);
+  if (EFI_ERROR (Status)) {
+    ASSERT_EFI_ERROR (Status);
+    return Status;
+  }
+
+  return Status;
+}
+
 /** Create a Cpu in the AML namespace from a CM_ARCH_COMMON_PROC_HIERARCHY_INFO
     CM object.
 
@@ -793,6 +865,19 @@ CreateAmlCpuFromProcHierarchy (
     return Status;
   }
 
+  if (ProcHierarchyNodeInfo->StaToken != CM_NULL_TOKEN) {
+    Status = CreateAmlStatus (
+               Generator,
+               CfgMgrProtocol,
+               ProcHierarchyNodeInfo->StaToken,
+               CpuNode
+               );
+    if (EFI_ERROR (Status)) {
+      ASSERT_EFI_ERROR (Status);
+      return Status;
+    }
+  }
+
   return Status;
 }
 
@@ -900,6 +985,19 @@ CreateAmlProcessorContainer (
     }
   }
 
+  if (ProcHierarchyNodeInfo->StaToken != CM_NULL_TOKEN) {
+    Status = CreateAmlStatus (
+               Generator,
+               CfgMgrProtocol,
+               ProcHierarchyNodeInfo->StaToken,
+               ProcContainerNode
+               );
+    if (EFI_ERROR (Status)) {
+      ASSERT_EFI_ERROR (Status);
+      return Status;
+    }
+  }
+
   *ProcContainerNodePtr = ProcContainerNode;
 
   return Status;