Allow writes to NVRAM partition in lockdown mode

NVRAM should be considered mutable in the same way as the VPD
caches are considered mutable.  If NVRAM is to be locked, a different
define to lock out NVRAM should also be set.

main.v

@@ -16,10 +16,13 @@
 // should be automatically retried on the next IPL
 `define BLOCK_GUARD_PARTITION_WRITES
 
-// Block writes to everything except DJVPD / MVPD / CVPD
+// Block writes to everything except DJVPD / MVPD / CVPD / NVRAM
 // This implicitly blocks GUARD partition writes
 `define BLOCK_NONESSENTIAL_WRITES
 
+// Block writes to NVRAM partition
+// `define BLOCK_NVRAM_PARTITION_WRITES
+
 `ifdef BLOCK_NONESSENTIAL_WRITES
 `undef BLOCK_GUARD_PARTITION_WRITES
 `endif
@@ -132,6 +135,8 @@ module lpc_bridge_top(
 `ifdef BLOCK_NONESSENTIAL_WRITES
 	parameter VPD_PARTITION_START_ADDRESS =   28'h0e5000;
 	parameter VPD_PARTITION_END_ADDRESS =     28'h204fff;
+	parameter NVRAM_PARTITION_START_ADDRESS = 28'h031000;
+	parameter NVRAM_PARTITION_END_ADDRESS =   28'h0c0fff;
 `endif
 
 	// Fully isolate / power down host interfaces on external request
@@ -1045,8 +1050,13 @@ module lpc_bridge_top(
 								|| (ipmi_bt_hiomap_active_window_start_address > GUARD_PARTITION_END_ADDRESS))
 `endif
 `ifdef BLOCK_NONESSENTIAL_WRITES
-								&& (((ipmi_bt_hiomap_active_window_start_address + ipmi_bt_hiomap_active_window_size_bytes) >= VPD_PARTITION_START_ADDRESS)
-								&& ((ipmi_bt_hiomap_active_window_start_address + ipmi_bt_hiomap_active_window_size_bytes) <= VPD_PARTITION_END_ADDRESS))
+								&& ((((ipmi_bt_hiomap_active_window_start_address + ipmi_bt_hiomap_active_window_size_bytes) >= VPD_PARTITION_START_ADDRESS)
+									&& ((ipmi_bt_hiomap_active_window_start_address + ipmi_bt_hiomap_active_window_size_bytes) <= VPD_PARTITION_END_ADDRESS))
+`ifndef BLOCK_NVRAM_PARTITION_WRITES
+								|| (((ipmi_bt_hiomap_active_window_start_address + ipmi_bt_hiomap_active_window_size_bytes) >= NVRAM_PARTITION_START_ADDRESS)
+									&& ((ipmi_bt_hiomap_active_window_start_address + ipmi_bt_hiomap_active_window_size_bytes) <= NVRAM_PARTITION_END_ADDRESS))
+`endif
+									)
 `endif
 								) begin