ice40: Introduce the concept of forPadIn SB_GB

Those are cells that are created mainly to handle the various sources a
global network can be driven from other than a user net.

When the flag is set, this means the global network usually driven by
this BEL is in fact driven by something else and so that SB_GB BEL and
matching global network can't be used.

This is also what gets used to set the extra bits during bitstream
generation.

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/ice40/archdefs.h b/ice40/archdefs.h
index b9614c07..8dcf0365 100644
--- a/ice40/archdefs.h
+++ b/ice40/archdefs.h
@@ -152,6 +152,10 @@ struct ArchCellInfo
             bool lvds;
             // TODO: clk packing checks...
         } ioInfo;
+        struct
+        {
+            bool forPadIn;
+        } gbInfo;
     };
 };