Potential forbidden axi write handshake dependency in debugging unit (#182)

axi_AW_allocator.sv

@@ -115,7 +115,25 @@ assign        awid_o[AXI_ID_OUT-1:AXI_ID_IN] = ID_o[LOG_N_TARG+N_TARG_PORT-1:N_T
 assign        awready_o = {N_TARG_PORT{grant_FIFO_ID_i}} & awready_int;
 assign        awvalid_o = awvalid_int & grant_FIFO_ID_i;
 
-assign        push_ID_o = awvalid_o & awready_i & grant_FIFO_ID_i;
+
+// Original code contains false dependency
+//   - AXI4 standard: 'the master must not wait for the slave to assert AWREADY or WREADY before asserting AWVALID or WVALID'
+//   - original code: assign push_ID_o = awvalid_o & awready_i & grant_FIFO_ID_i;
+
+// Therefore, push awvalid the first cycle that awvalid is asserted
+//   case 1: awvalid is asserted before awready is asserted
+//     - awvalid is pushed once. If awready goes high, r_busy is cleared for the next cycle.
+//   case 2: awvalid is asserted while awready is asserted (e.g. default accept)
+//     - awvalid is pushed, and r_busy is cleared for the next cycle.
+logic r_busy; 
+always @(posedge clk) begin
+    if(rst_n == 1'b0)
+        r_busy <= 0;
+    else
+        r_busy <= awvalid_o & ~|awready_o;
+end
+assign push_ID_o = (awvalid_o & (awvalid_o ^ r_busy)) & grant_FIFO_ID_i;
+
 
 generate
   for(i=0;i<N_TARG_PORT;i++)

axi_address_decoder_AW.sv

@@ -100,7 +100,26 @@ module axi_address_decoder_AW
 
 
   assign DEST_o      = match_region[N_INIT_PORT-1:0];
-  assign push_DEST_o = |(awvalid_i & awready_o) & ~error_detected;
+
+
+  // Original code contains false dependency
+  //   - AXI4 standard: 'the master must not wait for the slave to assert AWREADY or WREADY before asserting AWVALID or WVALID'
+  //   - original code: assign push_DEST_o = |(awvalid_i & awready_o) & ~error_detected;
+
+  // Therefore, push awvalid the first cycle that awvalid is asserted
+  //   case 1: awvalid is asserted before awready is asserted
+  //     - awvalid is pushed once. If awready goes high, r_busy is cleared for the next cycle.
+  //   case 2: awvalid is asserted while awready is asserted (e.g. default accept)
+  //     - awvalid is pushed, and r_busy is cleared for the next cycle.
+  logic r_busy; 
+  always @(posedge clk) begin
+      if(rst_n == 1'b0)
+          r_busy <= 0;
+      else
+          r_busy <= awvalid_i & ~awready_o;
+  end
+  assign push_DEST_o = (awvalid_i & (awvalid_i ^ r_busy)) & ~error_detected;
+
 
   enum logic [1:0]      { OPERATIVE, COMPLETE_PENDING, ACCEPT_WDATA , COMPLETE_ERROR_RESP } CS, NS;
 
@@ -188,7 +207,8 @@ module axi_address_decoder_AW
     end
   end
 
-  assign local_increm =  |(awvalid_o & awready_i);
+  assign local_increm = (awvalid_i & (awvalid_i ^ r_busy));
+
 
   always_comb
   begin