[edk2-devel] [PATCH v1 2/2] DynamicTablesPkg: Add an override for 16550 HID in SSDT

[Joey Gouly]

Some platforms advertise support for a 16550 UART, but are not
compatible with the PNP0500 HID. Allow them to override the HID by
setting PcdNonSbsaCompliantSerialHid.

Signed-off-by: Joey Gouly <joey.go...@arm.com>
---
 DynamicTablesPkg/DynamicTablesPkg.dec                                          
   |  3 +++
 
DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.inf
 |  4 +++-
 
DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.c 
  | 14 +++++++++++---
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/DynamicTablesPkg/DynamicTablesPkg.dec 
b/DynamicTablesPkg/DynamicTablesPkg.dec
index 
291a45a69679ae82219ecd2f26dfabfbab1f7f65..3ec4fff116a8f538be331edf341867948c025116
 100644
--- a/DynamicTablesPkg/DynamicTablesPkg.dec
+++ b/DynamicTablesPkg/DynamicTablesPkg.dec
@@ -44,5 +44,8 @@ [PcdsFixedAtBuild]
   # Maximum number of Custom DT Generators
   
gEdkiiDynamicTablesPkgTokenSpaceGuid.PcdMaxCustomDTGenerators|1|UINT16|0xC0000003
 
+  # Non SBSA Compliant Serial HID
+  
gEdkiiDynamicTablesPkgTokenSpaceGuid.PcdNonSbsaCompliantSerialHid|""|VOID*|0x40000008
+
 [Guids]
   gEdkiiDynamicTablesPkgTokenSpaceGuid = { 0xab226e66, 0x31d8, 0x4613, { 0x87, 
0x9d, 0xd2, 0xfa, 0xb6, 0x10, 0x26, 0x3c } }
diff --git 
a/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.inf
 
b/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.inf
index 
af3d404393f5f1385ab2d40f45f7222ab66f9b3a..b64825982e8fb7aaf78f3fd68992e1c78d20c408
 100644
--- 
a/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.inf
+++ 
b/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.inf
@@ -1,7 +1,7 @@
 ## @file
 #  SSDT Serial Port fixup Library
 #
-#  Copyright (c) 2020, Arm Limited. All rights reserved.<BR>
+#  Copyright (c) 2020 - 2021, Arm Limited. All rights reserved.<BR>
 #
 #  SPDX-License-Identifier: BSD-2-Clause-Patent
 ##
@@ -28,3 +28,5 @@ [LibraryClasses]
   AmlLib
   BaseLib
 
+[Pcd]
+  gEdkiiDynamicTablesPkgTokenSpaceGuid.PcdNonSbsaCompliantSerialHid
diff --git 
a/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.c
 
b/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.c
index 
0ff071485ef25f4ca63de0eeab5120d1beece4db..73a8087ed8a8ff84b64531a3c73d319585dfb6cf
 100644
--- 
a/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.c
+++ 
b/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.c
@@ -1,7 +1,7 @@
 /** @file
   SSDT Serial Port Fixup Library.
 
-  Copyright (c) 2019 - 2020, Arm Limited. All rights reserved.<BR>
+  Copyright (c) 2019 - 2021, Arm Limited. All rights reserved.<BR>
 
   SPDX-License-Identifier: BSD-2-Clause-Patent
 
@@ -139,13 +139,21 @@ FixupIds (
   AML_OBJECT_NODE_HANDLE    NameOpIdNode;
   CONST CHAR8             * HidString;
   CONST CHAR8             * CidString;
+  CONST CHAR8             * NonSbsaHid;
 
   // Get the _CID and _HID value to write.
   switch (SerialPortInfo->PortSubtype) {
     case EFI_ACPI_DBG2_PORT_SUBTYPE_SERIAL_FULL_16550:
     {
-      HidString = "PNP0501";
-      CidString = "PNP0500";
+      // If there is a non-SBSA compliant HID, use that.
+      NonSbsaHid = (CONST CHAR8*)PcdGetPtr (PcdNonSbsaCompliantSerialHid);
+      if ((NonSbsaHid != NULL) && (AsciiStrLen (NonSbsaHid) != 0)) {
+        HidString = NonSbsaHid;
+        CidString = "";
+      } else {
+        HidString = "PNP0501";
+        CidString = "PNP0500";
+      }
       break;
     }
     case EFI_ACPI_DBG2_PORT_SUBTYPE_SERIAL_ARM_PL011_UART:
-- 
Guid("CE165669-3EF3-493F-B85D-6190EE5B9759")



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