systemc: sync the response error between gem5 packet and tlm payload

For now we don't return the correct error status to the upstream of the
protocol conversion bridge. This prevents from the requestor to
distinguish if the response is good or not. This change fixes the issue.

Change-Id: Iec2a388b50fb1bd4fd97ece19e9061138b0b0a1f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/64591
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Earl Ou <shunhsingou@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/systemc/tlm_bridge/gem5_to_tlm.cc

@@ -194,6 +194,24 @@ packet2payload(PacketPtr packet)
     return trans;
 }
 
+void
+setPacketResponse(PacketPtr pkt, tlm::tlm_generic_payload &trans)
+{
+    pkt->makeResponse();
+
+    auto resp = trans.get_response_status();
+    switch (resp) {
+      case tlm::TLM_OK_RESPONSE:
+        break;
+      case tlm::TLM_COMMAND_ERROR_RESPONSE:
+        pkt->setBadCommand();
+        break;
+      default:
+        pkt->setBadAddress();
+        break;
+    }
+}
+
 template <unsigned int BITWIDTH>
 void
 Gem5ToTlmBridge<BITWIDTH>::pec(
@@ -225,7 +243,7 @@ Gem5ToTlmBridge<BITWIDTH>::pec(
         // we make a response packet before sending it back to the initiator
         // side gem5 module.
         if (packet->needsResponse()) {
-            packet->makeResponse();
+            setPacketResponse(packet, trans);
         }
         if (packet->isResponse()) {
             need_retry = !bridgeResponsePort.sendTimingResp(packet);
@@ -296,7 +314,7 @@ Gem5ToTlmBridge<BITWIDTH>::recvAtomic(PacketPtr packet)
     }
 
     if (packet->needsResponse())
-        packet->makeResponse();
+        setPacketResponse(packet, *trans);
 
     trans->release();
 
@@ -328,6 +346,7 @@ Gem5ToTlmBridge<BITWIDTH>::recvAtomicBackdoor(
         backdoor = getBackdoor(*trans);
     }
 
+    // Always set success response in Backdoor case.
     if (packet->needsResponse())
         packet->makeResponse();
 

src/systemc/tlm_bridge/tlm_to_gem5.cc

@@ -178,6 +178,18 @@ payload2packet(RequestorID _id, tlm::tlm_generic_payload &trans)
     return std::make_pair(pkt, true);
 }
 
+void
+setPayloadResponse(tlm::tlm_generic_payload &trans, PacketPtr pkt)
+{
+    if (!pkt->isError()) {
+        trans.set_response_status(tlm::TLM_OK_RESPONSE);
+    } else if (pkt->isRead() || pkt->isWrite()) {
+        trans.set_response_status(tlm::TLM_COMMAND_ERROR_RESPONSE);
+    } else {
+        trans.set_response_status(tlm::TLM_ADDRESS_ERROR_RESPONSE);
+    }
+}
+
 template <unsigned int BITWIDTH>
 void
 TlmToGem5Bridge<BITWIDTH>::sendEndReq(tlm::tlm_generic_payload &trans)
@@ -195,9 +207,15 @@ void
 TlmToGem5Bridge<BITWIDTH>::sendBeginResp(tlm::tlm_generic_payload &trans,
                                          sc_core::sc_time &delay)
 {
-    tlm::tlm_phase phase = tlm::BEGIN_RESP;
+    Gem5SystemC::Gem5Extension *extension = nullptr;
+    trans.get_extension(extension);
+    panic_if(extension == nullptr,
+             "Missing gem5 extension when sending BEGIN_RESP");
+    auto pkt = extension->getPacket();
 
-    trans.set_response_status(tlm::TLM_OK_RESPONSE);
+    setPayloadResponse(trans, pkt);
+
+    tlm::tlm_phase phase = tlm::BEGIN_RESP;
 
     auto status = socket->nb_transport_bw(trans, phase, delay);
 
@@ -252,8 +270,6 @@ TlmToGem5Bridge<BITWIDTH>::handleEndResp(tlm::tlm_generic_payload &trans)
 
     responseInProgress = false;
 
-    checkTransaction(trans);
-
     if (needToSendRetry) {
         bmp.sendRetryResp();
         needToSendRetry = false;
@@ -267,18 +283,6 @@ TlmToGem5Bridge<BITWIDTH>::destroyPacket(PacketPtr pkt)
     delete pkt;
 }
 
-template <unsigned int BITWIDTH>
-void
-TlmToGem5Bridge<BITWIDTH>::checkTransaction(tlm::tlm_generic_payload &trans)
-{
-    if (trans.is_response_error()) {
-        std::stringstream ss;
-        ss << "Transaction returned with error, response status = "
-           << trans.get_response_string();
-        SC_REPORT_ERROR("TLM-2", ss.str().c_str());
-    }
-}
-
 template <unsigned int BITWIDTH>
 void
 TlmToGem5Bridge<BITWIDTH>::invalidateDmi(const gem5::MemBackdoor &backdoor)
@@ -362,10 +366,10 @@ TlmToGem5Bridge<BITWIDTH>::b_transport(tlm::tlm_generic_payload &trans,
     // clean up
     delete senderState;
 
+    setPayloadResponse(trans, pkt);
+
     if (pkt_created)
         destroyPacket(pkt);
-
-    trans.set_response_status(tlm::TLM_OK_RESPONSE);
 }
 
 template <unsigned int BITWIDTH>
@@ -437,11 +441,11 @@ TlmToGem5Bridge<BITWIDTH>::get_direct_mem_ptr(tlm::tlm_generic_payload &trans,
     // clean up
     delete senderState;
 
+    setPayloadResponse(trans, pkt);
+
     if (pkt_created)
         destroyPacket(pkt);
 
-    trans.set_response_status(tlm::TLM_OK_RESPONSE);
-
     return backdoor != nullptr;
 }
 

src/systemc/tlm_bridge/tlm_to_gem5.hh

@@ -141,8 +141,6 @@ class TlmToGem5Bridge : public TlmToGem5BridgeBase
 
     void destroyPacket(gem5::PacketPtr pkt);
 
-    void checkTransaction(tlm::tlm_generic_payload &trans);
-
     void invalidateDmi(const gem5::MemBackdoor &backdoor);
 
   protected: