Add a specification for the pb_type.xml generator
Signed-off-by: David Shah <davey1576@gmail.com>
diff --git a/vlog_to_pbtype.py b/vlog_to_pbtype.py
new file mode 100644
index 0000000..225ff62
--- /dev/null
+++ b/vlog_to_pbtype.py
@@ -0,0 +1,46 @@
+#!/usr/bin/python3
+import yosys_exec
+import lxml.etree as ET
+import argparse, re
+import os, tempfile
+from yosys_json import YosysJson
+
+"""
+Convert a Verilog simulation model to a VPR `pb_type.xml`
+
+The following Verilog attributes are allowed on instances:
+ - (* PB_PATH="../path/to/pb_type.xml" *) : import the pb_type for a given instance
+ from an external XML file instead of including it inline.
+
+ - (* GENERATE_PB *) : generate (and overwrite if applicable) the above file, as well as including it
+
+The following are allowed on both instances (except where PB_PATH is set but GENERATE_PB isn't), and
+the top level module.
+
+ - (* BLIF_MODEL=".latch" *) : specify the corresponding blif_model for a given instance
+
+ - (* CLASS="flipflop" *) : specify the corresponding class for a given instance
+
+ - (* PB_NAME="name" *) : override the name of the pb_type (default: cell type)
+
+The following are allowed on nets within modules:
+
+ - (* SETUP="clk 10e-12" *) : specify setup time for a given clock
+
+ - (* HOLD="clk 10e-12" *) : specify hold time for a given clock
+
+ - (* CLK_TO_Q="clk 10e-12" *) : specify clock-to-output time for a given clock
+
+ - (* PB_MUX=1 *) : if the signal is driven by a $mux cell, generate a pb_type <mux> element for it
+"""
+
+parser = argparse.ArgumentParser(description='Convert a Verilog simulation model into a VPR pb_type.xml file')
+parser.add_argument('infiles', metavar='input.v', type=str, nargs='+',
+ help='one or more Verilog input files')
+parser.add_argument('--top', help='top level module, not needed if only one module across all files')
+parser.add_argument('-o', help='output filename, default model.xml')
+
+args = parser.parse_args()
+
+vjson = yosys_exec.vlog_to_json(args.infiles, False, False)
+yj = YosysJson(vjson)
