2 files changed, 11 insertions, 9 deletions
diff --git a/ArmPkg/Drivers/ArmScmiDxe/ScmiDxe.c b/ArmPkg/Drivers/ArmScmiDxe/ScmiDxe.c
index d5890a7633..fb4e79aa36 100644
--- a/ArmPkg/Drivers/ArmScmiDxe/ScmiDxe.c
+++ b/ArmPkg/Drivers/ArmScmiDxe/ScmiDxe.c
@@ -4,9 +4,9 @@
 
   SPDX-License-Identifier: BSD-2-Clause-Patent
 
-  System Control and Management Interface V1.0
-    http://infocenter.arm.com/help/topic/com.arm.doc.den0056a/
-    DEN0056A_System_Control_and_Management_Interface.pdf
+  @par Specification Reference:
+  - Arm System Control and Management Interface - Platform Design Document
+    (https://developer.arm.com/documentation/den0056/)
 **/
 
 #include <Base.h>
@@ -86,7 +86,9 @@ ArmScmiDxeEntryPoint (
     return Status;
   }
 
-  if (Version != BASE_PROTOCOL_VERSION) {
+  // Accept any version between SCMI v1.0 and SCMI v2.0
+  if ((Version < BASE_PROTOCOL_VERSION_V1) ||
+    (Version > BASE_PROTOCOL_VERSION_V2)) {
     ASSERT (FALSE);
     return EFI_UNSUPPORTED;
   }
diff --git a/ArmPkg/Include/Protocol/ArmScmiBaseProtocol.h b/ArmPkg/Include/Protocol/ArmScmiBaseProtocol.h
index 73ad3e32a2..c4b81c0f56 100644
--- a/ArmPkg/Include/Protocol/ArmScmiBaseProtocol.h
+++ b/ArmPkg/Include/Protocol/ArmScmiBaseProtocol.h
@@ -4,9 +4,9 @@
 
   SPDX-License-Identifier: BSD-2-Clause-Patent
 
-  System Control and Management Interface V1.0
-    http://infocenter.arm.com/help/topic/com.arm.doc.den0056a/
-    DEN0056A_System_Control_and_Management_Interface.pdf
+  @par Specification Reference:
+  - Arm System Control and Management Interface - Platform Design Document
+    (https://developer.arm.com/documentation/den0056/)
 **/
 
 #ifndef ARM_SCMI_BASE_PROTOCOL_H_
@@ -14,7 +14,8 @@
 
 #include <Protocol/ArmScmi.h>
 
-#define BASE_PROTOCOL_VERSION  0x10000
+#define BASE_PROTOCOL_VERSION_V1  0x10000
+#define BASE_PROTOCOL_VERSION_V2  0x20000
 
 #define NUM_PROTOCOL_MASK      0xFFU
 #define NUM_AGENT_MASK         0xFFU
@@ -165,4 +166,3 @@ typedef enum {
 } SCMI_MESSAGE_ID_BASE;
 
 #endif /* ARM_SCMI_BASE_PROTOCOL_H_ */
-