[PATCH v1 5/8] DynamicTablesPkg: IORT set reference to Id array only if present

["Sami Mujawar" <sami.mujawar@arm.com>]

The IORT table generator is setting up a reference to ID array for
nodes even when the ID Mapping count is zero. This is not an issue as an
OS would only access the ID Reference if the ID mapping count is not zero.

However, it would be good to set the reference to ID array to zero when
the ID Mapping count is zero rather than populating it with an incorrect
value.

Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
---
 DynamicTablesPkg/Library/Acpi/Arm/AcpiIortLibArm/IortGenerator.c | 29 +++++++++++---------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/DynamicTablesPkg/Library/Acpi/Arm/AcpiIortLibArm/IortGenerator.c b/DynamicTablesPkg/Library/Acpi/Arm/AcpiIortLibArm/IortGenerator.c
index 349caa8006bc34ca789cb3e321a0f87c0cd4ff0d..bdf839eab25e2b84b40c50da38f2bf961cdc5f42 100644
--- a/DynamicTablesPkg/Library/Acpi/Arm/AcpiIortLibArm/IortGenerator.c
+++ b/DynamicTablesPkg/Library/Acpi/Arm/AcpiIortLibArm/IortGenerator.c
@@ -1,7 +1,7 @@
 /** @file
   IORT Table Generator
 
-  Copyright (c) 2017 - 2020, ARM Limited. All rights reserved.
+  Copyright (c) 2017 - 2021, Arm Limited. All rights reserved.
   SPDX-License-Identifier: BSD-2-Clause-Patent
 
   @par Reference(s):
@@ -870,9 +870,9 @@ AddNamedComponentNodes (
     NcNode->Node.NumIdMappings = NodeList->IdMappingCount;
 
     ObjectNameLength = AsciiStrLen (NodeList->ObjectName) + 1;
-    NcNode->Node.IdReference =
-      (UINT32)(sizeof (EFI_ACPI_6_0_IO_REMAPPING_NAMED_COMP_NODE) +
-        (ALIGN_VALUE (ObjectNameLength, 4)));
+    NcNode->Node.IdReference = (NodeList->IdMappingCount == 0) ?
+      0 : ((UINT32)(sizeof (EFI_ACPI_6_0_IO_REMAPPING_NAMED_COMP_NODE) +
+           (ALIGN_VALUE (ObjectNameLength, 4))));
 
     // Named Component specific data
     NcNode->Flags = NodeList->Flags;
@@ -990,7 +990,8 @@ AddRootComplexNodes (
     RcNode->Node.Revision = 1;
     RcNode->Node.Reserved = EFI_ACPI_RESERVED_DWORD;
     RcNode->Node.NumIdMappings = NodeList->IdMappingCount;
-    RcNode->Node.IdReference = sizeof (EFI_ACPI_6_0_IO_REMAPPING_RC_NODE);
+    RcNode->Node.IdReference = (NodeList->IdMappingCount == 0) ?
+      0 : sizeof (EFI_ACPI_6_0_IO_REMAPPING_RC_NODE);
 
     // Root Complex specific data
     RcNode->CacheCoherent = NodeList->CacheCoherent;
@@ -1160,11 +1161,12 @@ AddSmmuV1V2Nodes (
     SmmuNode->Node.Revision = 0;
     SmmuNode->Node.Reserved = EFI_ACPI_RESERVED_DWORD;
     SmmuNode->Node.NumIdMappings = NodeList->IdMappingCount;
-    SmmuNode->Node.IdReference = sizeof (EFI_ACPI_6_0_IO_REMAPPING_SMMU_NODE) +
-      (NodeList->ContextInterruptCount *
-      sizeof (EFI_ACPI_6_0_IO_REMAPPING_SMMU_INT)) +
-      (NodeList->PmuInterruptCount *
-      sizeof (EFI_ACPI_6_0_IO_REMAPPING_SMMU_INT));
+    SmmuNode->Node.IdReference = (NodeList->IdMappingCount == 0) ?
+      0 : (sizeof (EFI_ACPI_6_0_IO_REMAPPING_SMMU_NODE) +
+           (NodeList->ContextInterruptCount *
+           sizeof (EFI_ACPI_6_0_IO_REMAPPING_SMMU_INT)) +
+           (NodeList->PmuInterruptCount *
+           sizeof (EFI_ACPI_6_0_IO_REMAPPING_SMMU_INT)));
 
     // SMMU v1/v2 specific data
     SmmuNode->Base = NodeList->BaseAddress;
@@ -1319,8 +1321,8 @@ AddSmmuV3Nodes (
     SmmuV3Node->Node.Revision = 2;
     SmmuV3Node->Node.Reserved = EFI_ACPI_RESERVED_DWORD;
     SmmuV3Node->Node.NumIdMappings = NodeList->IdMappingCount;
-    SmmuV3Node->Node.IdReference =
-      sizeof (EFI_ACPI_6_0_IO_REMAPPING_SMMU3_NODE);
+    SmmuV3Node->Node.IdReference = (NodeList->IdMappingCount == 0) ?
+      0 : sizeof (EFI_ACPI_6_0_IO_REMAPPING_SMMU3_NODE);
 
     // SMMUv3 specific data
     SmmuV3Node->Base = NodeList->BaseAddress;
@@ -1438,7 +1440,8 @@ AddPmcgNodes (
     PmcgNode->Node.Revision = 1;
     PmcgNode->Node.Reserved = EFI_ACPI_RESERVED_DWORD;
     PmcgNode->Node.NumIdMappings = NodeList->IdMappingCount;
-    PmcgNode->Node.IdReference = sizeof (EFI_ACPI_6_0_IO_REMAPPING_PMCG_NODE);
+    PmcgNode->Node.IdReference = (NodeList->IdMappingCount == 0) ?
+      0 : sizeof (EFI_ACPI_6_0_IO_REMAPPING_PMCG_NODE);
 
     // PMCG specific data
     PmcgNode->Base = NodeList->BaseAddress;
-- 
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'