From e72c8b8e09f35f42edf16e1364077e32fa4ce625 Mon Sep 17 00:00:00 2001
From: David Harris <David_Harris@hmc.edu>
Date: Tue, 2 Jul 2024 14:22:51 -0700
Subject: [PATCH] Watchdog timeout on buildroot boot is a halting criteria

---
 testbench/common/watchdog.sv | 14 ++++++++++----
 testbench/testbench.sv       |  5 ++---
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/testbench/common/watchdog.sv b/testbench/common/watchdog.sv
index 296900b20..69b185c40 100644
--- a/testbench/common/watchdog.sv
+++ b/testbench/common/watchdog.sv
@@ -26,7 +26,8 @@
 
 module watchdog #(parameter XLEN, WatchDogTimerThreshold) 
   (input clk,
-   input reset
+   input reset,
+   string TEST
    );
   
   // check for hang up.
@@ -46,9 +47,14 @@ module watchdog #(parameter XLEN, WatchDogTimerThreshold)
   always_comb begin
     WatchDogTimeOut = WatchDogTimerCount >= WatchDogTimerThreshold;
     if(WatchDogTimeOut) begin
-      $display("FAILURE: Watch Dog Time Out triggered. PCW stuck at %x for more than %d cycles", PCW, WatchDogTimerCount);
-      $stop;
-	end
+      if (TEST == "buildroot") $display("Watch Dog Time Out triggered.  This is a normal termination for a full buildroot boot.  Check sim/<simulator>/logs/buildroot_uart.log to check if the boot printed the login prompt.");
+      else $display("FAILURE: Watch Dog Time Out triggered. PCW stuck at %x for more than %d cycles", PCW, WatchDogTimerCount);
+      `ifdef QUESTA
+        $stop;  // if this is changed to $finish for Questa, wally-batch.do does not go to the next step to run coverage, and wally.do terminates without allowing GUI debug
+      `else
+        $finish;
+      `endif
+    end
   end
 
 endmodule
diff --git a/testbench/testbench.sv b/testbench/testbench.sv
index be0422550..f6087da1b 100644
--- a/testbench/testbench.sv
+++ b/testbench/testbench.sv
@@ -118,10 +118,9 @@ module testbench;
       TEST = "none";
     if (!$value$plusargs("ElfFile=%s", ElfFile))
       ElfFile = "none";
-    else begin
-    end
     if (!$value$plusargs("INSTR_LIMIT=%d", INSTR_LIMIT))
       INSTR_LIMIT = 0;
+    //$display("TEST = %s ElfFile = %s", TEST, ElfFile);
     
     // pick tests based on modes supported
     //tests = '{};
@@ -613,7 +612,7 @@ module testbench;
                 InstrFName, InstrDName, InstrEName, InstrMName, InstrWName);
 
   // watch for problems such as lockup, reading unitialized memory, bad configs
-  watchdog #(P.XLEN, 1000000) watchdog(.clk, .reset);  // check if PCW is stuck
+  watchdog #(P.XLEN, 1000000) watchdog(.clk, .reset, .TEST);  // check if PCW is stuck
   ramxdetector #(P.XLEN, P.LLEN) ramxdetector(clk, dut.core.lsu.MemRWM[1], dut.core.lsu.LSULoadAccessFaultM, dut.core.lsu.ReadDataM, 
                                       dut.core.ifu.PCM, InstrM, dut.core.lsu.IEUAdrM, InstrMName);
   riscvassertions #(P) riscvassertions();  // check assertions for a legal configuration