arm: Add a 'clear PPI' method to gic_pl390

The underlying assumption that all PPIs must be edge-triggered is
strained when the architected timers and VGIC interfaces make
level-behaviour observable. For example, a virtual timer interrupt
'goes away' when the hypervisor is entered and the vtimer is disabled;
this requires a PPI to be de-activated.

The new method simply clears the interrupt pending state.

3 files changed, 16 insertions, 3 deletions

diff --git a/src/dev/arm/base_gic.hh b/src/dev/arm/base_gic.hh
index d177487ed..facc99084 100644
--- a/src/dev/arm/base_gic.hh
+++ b/src/dev/arm/base_gic.hh
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012 ARM Limited
+ * Copyright (c) 2012-2013 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -75,6 +75,7 @@ class BaseGic :  public PioDevice
      * @param cpu CPU to forward interrupt to
      */
     virtual void sendPPInt(uint32_t num, uint32_t cpu) = 0;
+    virtual void clearPPInt(uint32_t num, uint32_t cpu) = 0;
 
     /**
      * Clear an interrupt from a device that is connected to the GIC.
diff --git a/src/dev/arm/gic_pl390.cc b/src/dev/arm/gic_pl390.cc
index 1acfdc707..fc49aa63e 100644
--- a/src/dev/arm/gic_pl390.cc
+++ b/src/dev/arm/gic_pl390.cc
@@ -692,7 +692,7 @@ Pl390::sendInt(uint32_t num)
 void
 Pl390::sendPPInt(uint32_t num, uint32_t cpu)
 {
-    DPRINTF(Interrupt, "Received Interrupt number %d, cpuTarget %#x: \n",
+    DPRINTF(Interrupt, "Received PPI %d, cpuTarget %#x: \n",
             num, cpu);
     cpuPpiPending[cpu] |= 1 << (num - SGI_MAX);
     updateIntState(intNumToWord(num));
@@ -705,6 +705,15 @@ Pl390::clearInt(uint32_t number)
 }
 
 void
+Pl390::clearPPInt(uint32_t num, uint32_t cpu)
+{
+    DPRINTF(Interrupt, "Clearing PPI %d, cpuTarget %#x: \n",
+            num, cpu);
+    cpuPpiPending[cpu] &= ~(1 << (num - SGI_MAX));
+    updateIntState(intNumToWord(num));
+}
+
+void
 Pl390::postInt(uint32_t cpu, Tick when)
 {
     if (!(postIntEvent[cpu]->scheduled()))
diff --git a/src/dev/arm/gic_pl390.hh b/src/dev/arm/gic_pl390.hh
index c2b0988f8..2621e1a27 100644
--- a/src/dev/arm/gic_pl390.hh
+++ b/src/dev/arm/gic_pl390.hh
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010 ARM Limited
+ * Copyright (c) 2010, 2013 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -287,6 +287,9 @@ class Pl390 : public BaseGic
      * Depending on the configuration, the gic may de-assert it's cpu line
      * @param number number of interrupt to send */
     void clearInt(uint32_t number);
+
+    /** Clear a (level-sensitive) PPI */
+    void clearPPInt(uint32_t num, uint32_t cpu);
     /** @} */
 
     /** @{ */