alternate remedy for endless feedback loop

Author: majbthrd

src/dm_mem.sv

@@ -132,33 +132,6 @@ module dm_mem #(
   typedef enum logic [1:0] { Idle, Go, Resume, CmdExecuting } state_e;
   state_e state_d, state_q;
 
-  // hart state decode
-  always_comb begin : p_state_decode
-    go               = 1'b0;
-    resume           = 1'b0;
-    cmdbusy_o        = 1'b1;
-
-    unique case (state_q)
-      Idle: begin
-        cmdbusy_o = 1'b0;
-        end
-      Go: begin
-        // we are already busy here since we scheduled the execution of a program
-        cmdbusy_o = 1'b1;
-        go        = 1'b1;
-      end
-      Resume: begin
-        cmdbusy_o = 1'b1;
-        resume = 1'b1;
-      end
-      CmdExecuting: begin
-        cmdbusy_o = 1'b1;
-        go        = 1'b0;
-      end
-      default: ;
-    endcase
-  end
-  
   // hart ctrl queue
   always_comb begin : p_hart_ctrl_queue
     cmderror_valid_o = 1'b0;
@@ -167,6 +140,9 @@ module dm_mem #(
 
     unique case (state_q)
       Idle: begin
+        cmdbusy_o = 1'b0;
+        go        = 1'b0;
+        resume    = 1'b0;
         if (cmd_valid_i && halted_q_aligned[hartsel] && !unsupported_command) begin
           // give the go signal
           state_d = Go;
@@ -184,26 +160,40 @@ module dm_mem #(
       end
 
       Go: begin
+        // we are already busy here since we scheduled the execution of a program
+        cmdbusy_o = 1'b1;
+        go        = 1'b1;
+        resume    = 1'b0;
         // the thread is now executing the command, track its state
         if (going) begin
             state_d = CmdExecuting;
         end
       end
 
       Resume: begin
+        cmdbusy_o = 1'b1;
+        go        = 1'b0;
+        resume    = 1'b1;
         if (resuming_q_aligned[hartsel]) begin
           state_d = Idle;
         end
       end
 
       CmdExecuting: begin
+        cmdbusy_o = 1'b1;
+        go        = 1'b0;
+        resume    = 1'b0;
         // wait until the hart has halted again
         if (halted_aligned[hartsel]) begin
           state_d = Idle;
         end
       end
 
-      default: ;
+      default: begin
+        cmdbusy_o = 1'b1;
+        go        = 1'b0;
+        resume    = 1'b0;
+      end
     endcase
 
     // only signal once that cmd is unsupported so that we can clear cmderr