devices: Fixed periodic interrupts to work with draining

Added drain functions to the RTC and 8254 timer so that periodic interrupts
stop when the system is draining.  This patch is needed to checkpoint in
timing mode.  Otherwise under certain situations, the event queue will never
be completely empty.

2 files changed, 17 insertions, 0 deletions

diff --git a/src/dev/alpha/tsunami_io.cc b/src/dev/alpha/tsunami_io.cc
index c90f06b5a..1a76c2c32 100644
--- a/src/dev/alpha/tsunami_io.cc
+++ b/src/dev/alpha/tsunami_io.cc
@@ -249,6 +249,17 @@ TsunamiIO::clearPIC(uint8_t bitvector)
     }
 }
 
+unsigned int 
+TsunamiIO::drain(Event *de)
+{
+    unsigned int count = 0;
+    count += pitimer.drain(de);
+    count += rtc.drain(de);
+    assert(count == 0);
+    changeState(SimObject::Drained);
+    return count;
+}
+
 void
 TsunamiIO::serialize(ostream &os)
 {
diff --git a/src/dev/alpha/tsunami_io.hh b/src/dev/alpha/tsunami_io.hh
index b6d63322b..f649247e2 100644
--- a/src/dev/alpha/tsunami_io.hh
+++ b/src/dev/alpha/tsunami_io.hh
@@ -141,6 +141,12 @@ class TsunamiIO : public BasicPioDevice
     void clearPIC(uint8_t bitvector);
 
     /**
+     * Drain the io state including all associated events.
+     * @param drainEvent
+     */
+    unsigned int drain(Event *de);
+
+    /**
      * Serialize this object to the given output stream.
      * @param os The stream to serialize to.
      */