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.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/dev/intel_8254_timer.hh b/src/dev/intel_8254_timer.hh
index 30ddc7bca..26ea0687e 100644
--- a/src/dev/intel_8254_timer.hh
+++ b/src/dev/intel_8254_timer.hh
@@ -137,6 +137,10 @@ class Intel8254Timer : public EventManager
         /** Pointer to container */
         Intel8254Timer *parent;
 
+        /** if non-zero, the scheduled tick of an event used for drain
+            serialization coordination */
+        Tick event_tick;
+
       public:
         Counter(Intel8254Timer *p, const std::string &name, unsigned int num);
 
@@ -165,6 +169,12 @@ class Intel8254Timer : public EventManager
         bool outputHigh();
 
         /**
+         * Drain all associated events.
+         * @param drainEvent
+         */
+        unsigned int drain(Event *de);
+
+        /**
          * Serialize this object to the given output stream.
          * @param base The base name of the counter object.
          * @param os   The stream to serialize to.
@@ -229,6 +239,8 @@ class Intel8254Timer : public EventManager
         return counter[num]->outputHigh();
     }
 
+    unsigned int drain(Event *de);
+
     /**
      * Serialize this object to the given output stream.
      * @param base The base name of the counter object.