From 9eb8590858d4acde6e1c3e86c4f20fb590cb2f71 Mon Sep 17 00:00:00 2001
From: Luke Wren <wren6991@gmail.com>
Date: Mon, 5 Sep 2022 00:36:41 +0100
Subject: [PATCH] Add generate to avoid elaborating internals of PMP/triggers
 with 0 PMP regions or triggers.

---
 hdl/hazard3_pmp.v      | 16 ++++++++++++++++
 hdl/hazard3_triggers.v | 16 ++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/hdl/hazard3_pmp.v b/hdl/hazard3_pmp.v
index 8803188..1f01df9 100644
--- a/hdl/hazard3_pmp.v
+++ b/hdl/hazard3_pmp.v
@@ -39,6 +39,19 @@ localparam PMP_A_NAPOT = 2'b11;
 
 `include "hazard3_csr_addr.vh"
 
+generate
+if (PMP_REGIONS == 0) begin: no_pmp
+
+// This should already be stubbed out in core.v, but use a generate here too
+// so that we don't get a warning for elaborating this module with a region
+// count of 0.
+
+always @ (*) cfg_rdata = {W_DATA{1'b0}};
+assign i_kill = 1'b0;
+assign d_kill = 1'b0;
+
+end else begin: have_pmp
+
 // ----------------------------------------------------------------------------
 // Config registers and read/write interface
 
@@ -279,6 +292,9 @@ assign i_kill = i_partial_match || (
 	(!i_m_mode || i_l || i_m) && !i_x
 );
 
+end
+endgenerate
+
 endmodule
 
 `ifndef YOSYS
diff --git a/hdl/hazard3_triggers.v b/hdl/hazard3_triggers.v
index 0ee98a9..fcff709 100644
--- a/hdl/hazard3_triggers.v
+++ b/hdl/hazard3_triggers.v
@@ -36,6 +36,19 @@ module hazard3_triggers #(
 
 `include "hazard3_csr_addr.vh"
 
+generate
+if (BREAKPOINT_TRIGGERS == 0) begin: no_triggers
+
+// The instantiation of this block should already be stubbed out in core.v if
+// there are no triggers, but we still get warnings for elaborating this
+// module with zero triggers, so add a generate block here too.
+
+always @ (*) cfg_rdata = {W_DATA{1'b0}};
+assign break_any = 1'b0;
+assign break_d_mode = 1'b0;
+
+end else begin: have_triggers
+
 // ----------------------------------------------------------------------------
 // Configuration state
 
@@ -156,6 +169,9 @@ end
 assign break_any    = |want_m_mode_break || |want_d_mode_break;
 assign break_d_mode = |want_d_mode_break;
 
+end
+endgenerate
+
 endmodule
 
 `ifndef YOSYS