mem-ruby: Add a DBID field to the CHIResponseMsg data type

This will hold the CHI Data Buffer Identifier (DBID) field.
The DBID allows a Completer of a transaction to provide its own
identifier for a transaction ID.
This new ID will be used as a TxnId field by a following
WriteData/CompData/CompAck response.

For now we only set it to the original txnId (identity mapping)

Change-Id: If30c5e1cafbe5a30073c7cd01d60bf41eb586cee
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>

src/mem/ruby/protocol/chi/CHI-cache-actions.sm

@@ -2135,6 +2135,16 @@ action(Receive_ReqResp_WUComp, desc="") {
   }
 }
 
+action(Receive_ReqResp_CopyDBID, desc="Copy the rsp DBID into the TBE") {
+  if (tbe.expected_req_resp.receivedRespType(CHIResponseType:DBIDResp) == false &&
+      tbe.expected_req_resp.receivedRespType(CHIResponseType:CompDBIDResp) == false) {
+    error("Received unexpected message");
+  }
+  peek(rspInPort, CHIResponseMsg) {
+    tbe.txnId := in_msg.dbid;
+  }
+}
+
 action(Receive_SnpResp, desc="") {
   assert(tbe.expected_snp_resp.hasExpected());
   peek(rspInPort, CHIResponseMsg) {
@@ -2557,6 +2567,7 @@ action(Send_CompI, desc="") {
     out_msg.type := CHIResponseType:Comp_I;
     out_msg.responder := machineID;
     out_msg.Destination.add(tbe.requestor);
+    out_msg.dbid := tbe.txnId;
   }
 }
 
@@ -2568,6 +2579,7 @@ action(Send_CompUC, desc="") {
     out_msg.responder := machineID;
     out_msg.Destination.add(tbe.requestor);
     out_msg.txnId := tbe.txnId;
+    out_msg.dbid := tbe.txnId;
   }
 }
 
@@ -2579,6 +2591,7 @@ action(Send_CompUC_Stale, desc="") {
     out_msg.responder := machineID;
     out_msg.Destination.add(tbe.requestor);
     out_msg.txnId := tbe.txnId;
+    out_msg.dbid := tbe.txnId;
     // We don't know if this is a stale clean unique or a bug, so flag the
     // reponse so the requestor can make further checks
     out_msg.stale := true;
@@ -2603,6 +2616,7 @@ action(Send_CompI_Stale, desc="") {
     out_msg.type := CHIResponseType:Comp_I;
     out_msg.responder := machineID;
     out_msg.Destination.add(tbe.requestor);
+    out_msg.dbid := tbe.txnId;
     // We don't know if this is a stale writeback or a bug, so flag the
     // reponse so the requestor can make further checks
     out_msg.stale := true;
@@ -2617,6 +2631,7 @@ action(Send_CompDBIDResp, desc="") {
     out_msg.responder := machineID;
     out_msg.Destination.add(tbe.requestor);
     out_msg.txnId := tbe.txnId;
+    out_msg.dbid := tbe.txnId;
   }
 }
 
@@ -2627,6 +2642,7 @@ action(Send_CompDBIDResp_Stale, desc="") {
     out_msg.type := CHIResponseType:CompDBIDResp;
     out_msg.responder := machineID;
     out_msg.Destination.add(tbe.requestor);
+    out_msg.dbid := tbe.txnId;
     // We don't know if this is a stale writeback or a bug, so flag the
     // reponse so the requestor can make further checks
     out_msg.stale := true;
@@ -2640,6 +2656,7 @@ action(Send_DBIDResp, desc="") {
     out_msg.type := CHIResponseType:DBIDResp;
     out_msg.responder := machineID;
     out_msg.Destination.add(tbe.requestor);
+    out_msg.dbid := tbe.txnId;
   }
 }
 

src/mem/ruby/protocol/chi/CHI-cache-transitions.sm

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2022 ARM Limited
+ * Copyright (c) 2021-2023 Arm Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -1212,8 +1212,7 @@ transition(BUSY_BLKD,
 }
 
 // waiting for WB or evict ack
-transition(BUSY_INTR,
-           {CompDBIDResp,Comp_I}, BUSY_BLKD) {
+transition(BUSY_INTR, Comp_I, BUSY_BLKD) {
   Receive_ReqResp;
   Profile_OutgoingEnd_DatalessResp;
   Pop_RespInQueue;
@@ -1229,9 +1228,19 @@ transition(BUSY_INTR, Comp_UC, BUSY_BLKD) {
   ProcessNextState;
 }
 
+// waiting for WB or evict ack
+transition(BUSY_INTR, CompDBIDResp, BUSY_BLKD) {
+  Receive_ReqResp;
+  Receive_ReqResp_CopyDBID;
+  Profile_OutgoingEnd_DatalessResp;
+  Pop_RespInQueue;
+  ProcessNextState;
+}
+
 // alternative flow for WU with separate Comp
 transition(BUSY_INTR, DBIDResp, BUSY_BLKD) {
   Receive_ReqResp;
+  Receive_ReqResp_CopyDBID;
   Receive_ReqResp_WUNeedComp;
   Pop_RespInQueue;
   ProcessNextState;

src/mem/ruby/protocol/chi/CHI-msg.sm

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021 ARM Limited
+ * Copyright (c) 2021, 2023 Arm Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -156,6 +156,7 @@ structure(CHIResponseMsg, desc="", interface="Message") {
   bool stale,           desc="Response to a stale request";
   bool usesTxnId,       desc="True if using a Transaction ID", default="false";
   Addr txnId,           desc="Transaction ID", default="0";
+  Addr dbid,            desc="Data Buffer ID", default="0";
   //NOTE: not in CHI and for debuging only
 
   MessageSizeType MessageSize, default="MessageSizeType_Control";