global route: default to 20 iterations

this is enough for all projects in the test suite, except
sky130hd microwatt, so add exception for that design only

Signed-off-by: Øyvind Harboe <[email protected]>

Author: oharboe

flow/designs/sky130hd/microwatt/config.mk

@@ -30,3 +30,5 @@ export CTS_CLUSTER_DIAMETER = 100
 export CTS_CLUSTER_SIZE = 30
 
 export export SETUP_SLACK_MARGIN = 0.2
+
+export GLOBAL_ROUTE_ARGS=-congestion_iterations 100 -verbose

flow/scripts/global_route.tcl

@@ -18,7 +18,7 @@ if {[info exist env(FASTROUTE_TCL)]} {
 
 global_route -guide_file $env(RESULTS_DIR)/route.guide \
                -congestion_report_file $env(REPORTS_DIR)/congestion.rpt \
-               {*}[expr {[info exists ::env(GLOBAL_ROUTE_ARGS)] ? $::env(GLOBAL_ROUTE_ARGS) : {-congestion_iterations 40 -verbose}}]
+               {*}[expr {[info exists ::env(GLOBAL_ROUTE_ARGS)] ? $::env(GLOBAL_ROUTE_ARGS) : {-congestion_iterations 20 -verbose}}]
 
 set_propagated_clock [all_clocks]
 estimate_parasitics -global_routing