ruby: Simplify RubyPort flow control and routing

This patch simplfies the retry logic in the RubyPort, avoiding
redundant attributes, and enforcing more stringent checks on the
interactions with the normal ports. The patch also simplifies the
routing done by the RubyPort, using the port identifiers instead of a
heavy-weight sender state.

The patch also fixes a bug in the sending of responses from PIO
ports. Previously these responses bypassed the queue in the queued
port, and ignored the return value, potentially leading to response
packets being lost.

Committed by: Nilay Vaish <nilay@cs.wisc.edu>

1 files changed, 2 insertions, 7 deletions

diff --git a/src/mem/ruby/system/Sequencer.cc b/src/mem/ruby/system/Sequencer.cc
index be554d5cf..8d9640a04 100644
--- a/src/mem/ruby/system/Sequencer.cc
+++ b/src/mem/ruby/system/Sequencer.cc
@@ -553,15 +553,10 @@ Sequencer::hitCallback(SequencerRequest* srequest, DataBlock& data,
     // If using the RubyTester, update the RubyTester sender state's
     // subBlock with the recieved data.  The tester will later access
     // this state.
-    // Note: RubyPort will access it's sender state before the
-    // RubyTester.
     if (m_usingRubyTester) {
-        RubyPort::SenderState *reqSenderState =
-            safe_cast<RubyPort::SenderState*>(pkt->senderState);
-        // @todo This is a dangerous assumption on nothing else
-        // modifying the senderState
         RubyTester::SenderState* testerSenderState =
-            safe_cast<RubyTester::SenderState*>(reqSenderState->predecessor);
+            pkt->findNextSenderState<RubyTester::SenderState>();
+        assert(testerSenderState);
         testerSenderState->subBlock.mergeFrom(data);
     }