mem: Align rules for sinking inhibited packets at the slave

This patch aligns how the memory-system slaves, i.e. the various
memory controllers and the bridge, identify and deal with sinking of
inhibited packets that are only useful within the coherent part of the
memory system.

In the future we could shift the onus to the crossbar, and add a
parameter "is_point_of_coherence" that would allow it to sink the
aforementioned packets.

1 files changed, 7 insertions, 5 deletions

diff --git a/src/mem/dramsim2.cc b/src/mem/dramsim2.cc
index cd0f45b23..58227e06a 100644
--- a/src/mem/dramsim2.cc
+++ b/src/mem/dramsim2.cc
@@ -175,16 +175,18 @@ DRAMSim2::recvFunctional(PacketPtr pkt)
 bool
 DRAMSim2::recvTimingReq(PacketPtr pkt)
 {
-    // we should never see a new request while in retry
-    assert(!retryReq);
-
+    // sink inhibited packets without further action
     if (pkt->memInhibitAsserted()) {
-        // snooper will supply based on copy of packet
-        // still target's responsibility to delete packet
         pendingDelete.reset(pkt);
         return true;
     }
 
+    // we should not get a new request after committing to retry the
+    // current one, but unfortunately the CPU violates this rule, so
+    // simply ignore it for now
+    if (retryReq)
+        return false;
+
     // if we cannot accept we need to send a retry once progress can
     // be made
     bool can_accept = nbrOutstanding() < wrapper.queueSize();