2 files changed, 38 insertions, 4 deletions
diff --git a/ArmPkg/Drivers/TimerDxe/TimerDxe.c b/ArmPkg/Drivers/TimerDxe/TimerDxe.c
index 37859e1..b7f5ecc 100644
--- a/ArmPkg/Drivers/TimerDxe/TimerDxe.c
+++ b/ArmPkg/Drivers/TimerDxe/TimerDxe.c
@@ -22,6 +22,8 @@
 #include <Protocol/Timer.h>
 #include <Protocol/HardwareInterrupt.h>
 
+#include "TimerDxe.h"
+
 // The notification function to call on every timer interrupt.
 EFI_TIMER_NOTIFY  mTimerNotifyFunction     = (EFI_TIMER_NOTIFY)NULL;
 EFI_EVENT         EfiExitBootServicesEvent = (EFI_EVENT)NULL;
@@ -359,6 +361,9 @@ TimerInitialize (
   EFI_STATUS  Status;
   UINTN       TimerCtrlReg;
   UINT32      TimerHypIntrNum;
+  UINT32      TimerVirtIntrNum;
+  UINT32      TimerSecIntrNum;
+  UINT32      TimerIntrNum;
 
   if (ArmIsArchTimerImplemented () == 0) {
     DEBUG ((DEBUG_ERROR, "ARM Architectural Timer is not available in the CPU, hence can't use this Driver \n"));
@@ -377,27 +382,38 @@ TimerInitialize (
   Status = TimerDriverSetTimerPeriod (&gTimer, 0);
   ASSERT_EFI_ERROR (Status);
 
+  if (ArmHasGicV5SystemRegisters ()) {
+    TimerSecIntrNum  = GICV5_ARCH_TIMER_SEC_INTID;
+    TimerIntrNum     = GICV5_ARCH_TIMER_INTID;
+    TimerHypIntrNum  = GICV5_ARCH_TIMER_HYP_INTID;
+    TimerVirtIntrNum = GICV5_ARCH_TIMER_VIRT_INTID;
+  } else {
+    TimerVirtIntrNum = PcdGet32 (PcdArmArchTimerVirtIntrNum);
+    TimerHypIntrNum  = PcdGet32 (PcdArmArchTimerHypIntrNum);
+    TimerSecIntrNum  = PcdGet32 (PcdArmArchTimerSecIntrNum);
+    TimerIntrNum     = PcdGet32 (PcdArmArchTimerIntrNum);
+  }
+
   // Install secure and Non-secure interrupt handlers
   // Note: Because it is not possible to determine the security state of the
   // CPU dynamically, we just install interrupt handler for both sec and non-sec
   // timer PPI
-  Status = gInterrupt->RegisterInterruptSource (gInterrupt, PcdGet32 (PcdArmArchTimerVirtIntrNum), TimerInterruptHandler);
+  Status = gInterrupt->RegisterInterruptSource (gInterrupt, TimerVirtIntrNum, TimerInterruptHandler);
   ASSERT_EFI_ERROR (Status);
 
   //
   // The hypervisor timer interrupt may be omitted by implementations that
   // execute under virtualization.
   //
-  TimerHypIntrNum = PcdGet32 (PcdArmArchTimerHypIntrNum);
   if (TimerHypIntrNum != 0) {
     Status = gInterrupt->RegisterInterruptSource (gInterrupt, TimerHypIntrNum, TimerInterruptHandler);
     ASSERT_EFI_ERROR (Status);
   }
 
-  Status = gInterrupt->RegisterInterruptSource (gInterrupt, PcdGet32 (PcdArmArchTimerSecIntrNum), TimerInterruptHandler);
+  Status = gInterrupt->RegisterInterruptSource (gInterrupt, TimerSecIntrNum, TimerInterruptHandler);
   ASSERT_EFI_ERROR (Status);
 
-  Status = gInterrupt->RegisterInterruptSource (gInterrupt, PcdGet32 (PcdArmArchTimerIntrNum), TimerInterruptHandler);
+  Status = gInterrupt->RegisterInterruptSource (gInterrupt, TimerIntrNum, TimerInterruptHandler);
   ASSERT_EFI_ERROR (Status);
 
   // Set up default timer
diff --git a/ArmPkg/Drivers/TimerDxe/TimerDxe.h b/ArmPkg/Drivers/TimerDxe/TimerDxe.h
new file mode 100644
index 0000000..98b2f9f
--- /dev/null
+++ b/ArmPkg/Drivers/TimerDxe/TimerDxe.h
@@ -0,0 +1,18 @@
+/** @file
+*
+*  Copyright (c) 2025, ARM Limited. All rights reserved.
+*
+*  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#ifndef TIMER_DXE_H_
+#define TIMER_DXE_H_
+
+// Timer IntIDs are architecturally defined for GICv5
+#define GICV5_ARCH_TIMER_HYP_INTID       0x2000001a
+#define GICV5_ARCH_TIMER_VIRT_INTID      0x2000001b
+#define GICV5_ARCH_TIMER_HYP_VIRT_INTID  0x2000001c
+#define GICV5_ARCH_TIMER_SEC_INTID       0x2000001d
+#define GICV5_ARCH_TIMER_INTID           0x2000001e
+
+#endif // TIMER_DXE_H_