From 42c0019f27516c4927a2729a0086833cf5425fff Mon Sep 17 00:00:00 2001
From: Joey Gouly <joey.gouly@arm.com>
Date: Fri, 22 Jan 2021 12:51:12 +0000
Subject: [PATCH] DynamicTablesPkg: Add an override for 16550 HID in SSDT

Some platforms advertise support for a 16550 UART, but are not
compatible with the PNP0500 HID. Allow them to override the HID by
setting PcdNonBsaCompliant16550SerialHid.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
---
 DynamicTablesPkg/DynamicTablesPkg.dec              |  3 +++
 .../SsdtSerialPortFixupLib.c                       | 14 +++++++++++---
 .../SsdtSerialPortFixupLib.inf                     |  4 +++-
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/DynamicTablesPkg/DynamicTablesPkg.dec b/DynamicTablesPkg/DynamicTablesPkg.dec
index 291a45a696..b242df0105 100644
--- a/DynamicTablesPkg/DynamicTablesPkg.dec
+++ b/DynamicTablesPkg/DynamicTablesPkg.dec
@@ -44,5 +44,8 @@
   # Maximum number of Custom DT Generators
   gEdkiiDynamicTablesPkgTokenSpaceGuid.PcdMaxCustomDTGenerators|1|UINT16|0xC0000003
 
+  # Non BSA Compliant 16550 Serial HID
+  gEdkiiDynamicTablesPkgTokenSpaceGuid.PcdNonBsaCompliant16550SerialHid|""|VOID*|0x40000008
+
 [Guids]
   gEdkiiDynamicTablesPkgTokenSpaceGuid = { 0xab226e66, 0x31d8, 0x4613, { 0x87, 0x9d, 0xd2, 0xfa, 0xb6, 0x10, 0x26, 0x3c } }
diff --git a/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.c b/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.c
index 0ff071485e..3c4356097c 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             * NonBsaHid;
 
   // 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-BSA compliant HID, use that.
+      NonBsaHid = (CONST CHAR8*)PcdGetPtr (PcdNonBsaCompliant16550SerialHid);
+      if ((NonBsaHid != NULL) && (AsciiStrLen (NonBsaHid) != 0)) {
+        HidString = NonBsaHid;
+        CidString = "";
+      } else {
+        HidString = "PNP0501";
+        CidString = "PNP0500";
+      }
       break;
     }
     case EFI_ACPI_DBG2_PORT_SUBTYPE_SERIAL_ARM_PL011_UART:
diff --git a/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.inf b/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.inf
index af3d404393..54bf71a3b7 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 @@
   AmlLib
   BaseLib
 
+[Pcd]
+  gEdkiiDynamicTablesPkgTokenSpaceGuid.PcdNonBsaCompliant16550SerialHid