cpu: Stream/SubstreamID support in TrafficGen

This patch is adding support for generating memory requests which set
the StreamID/SubstreamID field, so that is possible to emulate devices
attached to an external IOMMU/SMMU with a Traffic generator.

Change-Id: Iea068de581ae7125a9d49314124a08c045c75b49
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/12188

1 files changed, 20 insertions, 1 deletions

diff --git a/src/cpu/testers/traffic_gen/base.cc b/src/cpu/testers/traffic_gen/base.cc
index 6778e417b..ad4f67d9d 100644
--- a/src/cpu/testers/traffic_gen/base.cc
+++ b/src/cpu/testers/traffic_gen/base.cc
@@ -52,6 +52,7 @@
 #include "cpu/testers/traffic_gen/idle_gen.hh"
 #include "cpu/testers/traffic_gen/linear_gen.hh"
 #include "cpu/testers/traffic_gen/random_gen.hh"
+#include "cpu/testers/traffic_gen/stream_gen.hh"
 #include "debug/Checkpoint.hh"
 #include "debug/TrafficGen.hh"
 #include "params/BaseTrafficGen.hh"
@@ -78,7 +79,12 @@ BaseTrafficGen::BaseTrafficGen(const BaseTrafficGenParams* p)
       retryPkt(NULL),
       retryPktTick(0),
       updateEvent([this]{ update(); }, name()),
-      masterID(system->getMasterId(this))
+      masterID(system->getMasterId(this)),
+      streamGenerator(StreamGen::create(p))
+{
+}
+
+BaseTrafficGen::~BaseTrafficGen()
 {
 }
 
@@ -172,6 +178,19 @@ BaseTrafficGen::update()
         // get the next packet and try to send it
         PacketPtr pkt = activeGenerator->getNextPacket();
 
+        // If generating stream/substream IDs are enabled,
+        // try to pick and assign them to the new packet
+        if (streamGenerator) {
+            auto sid = streamGenerator->pickStreamID();
+            auto ssid = streamGenerator->pickSubStreamID();
+
+            pkt->req->setStreamId(sid);
+
+            if (streamGenerator->ssidValid()) {
+                pkt->req->setSubStreamId(ssid);
+            }
+        }
+
         // suppress packets that are not destined for a memory, such as
         // device accesses that could be part of a trace
         if (pkt && system->isMemAddr(pkt->getAddr())) {