sky130hd/uW:

    1. Use a custom blockage halo to make channels between macros
       inaccessible for GPL in order to avoid congestion problems.
    2. Use a higher placement density for GPL to run with the new
       blockages.

Signed-off-by: Arthur Koucher <[email protected]>

Author: AcKoucher

flow/designs/sky130hd/microwatt/config.mk

@@ -25,6 +25,16 @@ export SYNTH_HIERARCHICAL = 1
 
 export MACRO_PLACE_HALO = 100 100
 
+# We use large placement blockages to try eliminating the channels between
+# RAMs in order to make that space inaccessible for GPL. Experiments have
+# showed that connections crossing the RAMs vertically can be painful to
+# route.
+export MACRO_BLOCKAGE_HALO = 151
+
+# There's less space due to the adapted blockage halos, so GPL requires a
+# higher density in order to run.
+export PLACE_DENSITY = 0.21
+
 # CTS tuning
 export CTS_BUF_DISTANCE = 600
 export SKIP_GATE_CLONING = 1