diff --git a/Makefile.master b/Makefile.master
new file mode 100644
index 0000000..f6b5af4
--- /dev/null
+++ b/Makefile.master
@@ -0,0 +1,305 @@
+# SPDX-FileCopyrightText: 2020 Efabless Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+# cannot commit files larger than 100 MB to GitHub
+FILE_SIZE_LIMIT_MB = 100
+
+# Commands to be used to compress/uncompress files
+# they must operate **in place** (otherwise, modify the target to delete the
+# intermediate file/archive)
+COMPRESS ?= gzip -n --best
+UNCOMPRESS ?= gzip -d
+ARCHIVE_EXT ?= gz
+
+# The following variables are to build static pattern rules
+
+# Needed to rebuild archives that were previously split
+SPLIT_FILES := $(shell find . -type f -name "*.$(ARCHIVE_EXT).00.split")
+SPLIT_FILES_SOURCES := $(basename $(basename $(basename $(SPLIT_FILES))))
+
+# Needed to uncompress the existing archives
+ARCHIVES := $(shell find . -type f -name "*.$(ARCHIVE_EXT)")
+ARCHIVE_SOURCES := $(basename $(ARCHIVES))
+
+# Needed to compress and split files/archives that are too large
+LARGE_FILES := $(shell find ./gds -type f -name "*.gds")
+LARGE_FILES += $(shell find . -type f -size +$(FILE_SIZE_LIMIT_MB)M -not -path "./.git/*" -not -path "./gds/*" -not -path "./openlane/*")
+LARGE_FILES_GZ := $(addsuffix .$(ARCHIVE_EXT), $(LARGE_FILES))
+LARGE_FILES_GZ_SPLIT := $(addsuffix .$(ARCHIVE_EXT).00.split, $(LARGE_FILES))
+# consider splitting existing archives
+LARGE_FILES_GZ_SPLIT += $(addsuffix .00.split, $(ARCHIVES))
+
+# PDK setup configs
+THREADS ?= $(shell nproc)
+STD_CELL_LIBRARY ?= sky130_fd_sc_hd
+SPECIAL_VOLTAGE_LIBRARY ?= sky130_fd_sc_hvl
+IO_LIBRARY ?= sky130_fd_io
+SKYWATER_COMMIT ?= 3d7617a1acb92ea883539bcf22a632d6361a5de4
+OPEN_PDKS_COMMIT ?= 49fc7125db927de199d1f69e002beadc0a29881b
+
+.DEFAULT_GOAL := ship
+# We need portable GDS_FILE pointers...
+.PHONY: ship
+ship: check-env uncompress
+	@echo "###############################################"
+	@echo "Generating Caravel GDS (sources are in the 'gds' directory)"
+	@sleep 1
+	@echo "\
+		gds readonly true; \
+		gds rescale false; \
+		gds read ../gds/user_project_wrapper.gds; \
+		load caravel -dereference;\
+		select top cell;\
+		gds write caravel.gds; \
+		exit;" > ./mag/mag2gds_caravel.tcl
+	@cd mag && PDKPATH=${PDK_ROOT}/sky130A magic -noc -dnull mag2gds_caravel.tcl < /dev/null
+	@rm ./mag/mag2gds_caravel.tcl
+	@mv -f ./gds/caravel.gds ./gds/caravel.old.gds
+	mv ./mag/caravel.gds ./gds
+
+
+
+.PHONY: clean
+clean:
+	cd ./verilog/dv/caravel/mgmt_soc/ && \
+		$(MAKE) -j$(THREADS) clean
+	cd ./verilog/dv/caravel/user_proj_example/ && \
+		$(MAKE) -j$(THREADS) clean
+
+
+.PHONY: verify
+verify:
+	cd ./verilog/dv/caravel/mgmt_soc/ && \
+		$(MAKE) -j$(THREADS) all
+	cd ./verilog/dv/caravel/user_proj_example/ && \
+		$(MAKE) -j$(THREADS) all
+
+
+
+#####
+$(LARGE_FILES_GZ): %.$(ARCHIVE_EXT): %
+	@if ! [ $(suffix $<) == ".$(ARCHIVE_EXT)" ]; then\
+		$(COMPRESS) $< > /dev/null &&\
+		echo "$< -> $@";\
+	fi
+
+$(LARGE_FILES_GZ_SPLIT): %.$(ARCHIVE_EXT).00.split: %.$(ARCHIVE_EXT)
+	@if [ -n "$$(find "$<" -prune -size +$(FILE_SIZE_LIMIT_MB)M)" ]; then\
+		split $< -b $(FILE_SIZE_LIMIT_MB)M $<. -d --additional-suffix=.split &&\
+		rm $< &&\
+		echo -n "$< -> $$(ls $<.*.split)" | tr '\n' ' ' && echo "";\
+	fi
+
+# This target compresses all files larger than $(FILE_SIZE_LIMIT_MB) MB
+.PHONY: compress
+compress: $(LARGE_FILES_GZ) $(LARGE_FILES_GZ_SPLIT)
+	@echo "Files larger than $(FILE_SIZE_LIMIT_MB) MBytes are compressed!"
+
+
+
+#####
+$(ARCHIVE_SOURCES): %: %.$(ARCHIVE_EXT)
+	@$(UNCOMPRESS) $<
+	@echo "$< -> $@"
+
+.SECONDEXPANSION:
+$(SPLIT_FILES_SOURCES): %: $$(sort $$(wildcard %.$(ARCHIVE_EXT).*.split))
+	@cat $? > $@.$(ARCHIVE_EXT)
+	@rm $?
+	@echo "$? -> $@.$(ARCHIVE_EXT)"
+	@$(UNCOMPRESS) $@.$(ARCHIVE_EXT)
+	@echo "$@.$(ARCHIVE_EXT) -> $@"
+
+
+.PHONY: uncompress
+uncompress: $(SPLIT_FILES_SOURCES) $(ARCHIVE_SOURCES)
+	@echo "All files are uncompressed!"
+
+
+# LVS
+BLOCKS = $(shell cd openlane && find * -maxdepth 0 -type d)
+LVS_BLOCKS = $(foreach block, $(BLOCKS), lvs-$(block))
+$(LVS_BLOCKS): lvs-% : ./mag/%.mag ./verilog/gl/%.v
+	echo "Extracting $*"
+	mkdir -p ./mag/tmp
+	echo "load $* -dereference;\
+		select top cell;\
+		foreach cell [cellname list children] {\
+			load \$$cell -dereference;\
+			property LEFview TRUE;\
+		};\
+		load $* -dereference;\
+		select top cell;\
+		extract no all;\
+		extract do local;\
+		extract unique;\
+		extract;\
+		ext2spice lvs;\
+		ext2spice $*.ext;\
+		feedback save extract_$*.log;\
+		exit;" > ./mag/extract_$*.tcl
+	cd mag && export MAGTYPE=maglef; magic -rcfile ${PDK_ROOT}/sky130A/libs.tech/magic/current/sky130A.magicrc -noc -dnull extract_$*.tcl < /dev/null
+	mv ./mag/$*.spice ./spi/lvs
+	rm ./mag/*.ext
+	mv -f ./mag/extract_$*.{tcl,log} ./mag/tmp
+	####
+	mkdir -p ./spi/lvs/tmp
+	sh ./spi/lvs/run_lvs.sh ./spi/lvs/$*.spice ./verilog/gl/$*.v $*
+	@echo ""
+	python3 ./scripts/count_lvs.py -f ./verilog/gl/$*.v_comp.json | tee ./spi/lvs/tmp/$*.lvs.summary.log
+	mv -f ./verilog/gl/*{.out,.json,.log} ./spi/lvs/tmp 2> /dev/null || true
+	@echo ""
+	@echo "LVS: ./spi/lvs/$*.spice vs. ./verilog/gl/$*.v"
+	@echo "Comparison result: ./spi/lvs/tmp/$*.v_comp.out"
+
+# connect-by-label is enabled here!
+LVS_MAGLEF_BLOCKS = $(foreach block, $(BLOCKS), lvs-maglef-$(block))
+$(LVS_MAGLEF_BLOCKS): lvs-maglef-% : ./mag/%.mag ./verilog/gl/%.v
+	echo "Extracting $*"
+	mkdir -p ./maglef/tmp
+	echo "load $* -dereference;\
+		select top cell;\
+		foreach cell [cellname list children] {\
+			load \$$cell -dereference;\
+			property LEFview TRUE;\
+		};\
+		load $* -dereference;\
+		select top cell;\
+		extract no all;\
+		extract do local;\
+		extract;\
+		ext2spice lvs;\
+		ext2spice $*.ext;\
+		feedback save extract_$*.log;\
+		exit;" > ./mag/extract_$*.tcl
+	cd mag && export MAGTYPE=maglef; magic -noc -dnull extract_$*.tcl < /dev/null
+	mv ./mag/$*.spice ./spi/lvs
+	rm ./maglef/*.ext
+	mv -f ./mag/extract_$*.{tcl,log} ./maglef/tmp
+	####
+	mkdir -p ./spi/lvs/tmp
+	sh ./spi/lvs/run_lvs.sh ./spi/lvs/$*.spice ./verilog/gl/$*.v $*
+	@echo ""
+	python3 ./scripts/count_lvs.py -f ./verilog/gl/$*.v_comp.json | tee ./spi/lvs/tmp/$*.maglef.lvs.summary.log
+	mv -f ./verilog/gl/*{.out,.json,.log} ./spi/lvs/tmp 2> /dev/null || true
+	@echo ""
+	@echo "LVS: ./spi/lvs/$*.spice vs. ./verilog/gl/$*.v"
+	@echo "Comparison result: ./spi/lvs/tmp/$*.v_comp.out"
+
+# DRC
+BLOCKS = $(shell cd openlane && find * -maxdepth 0 -type d)
+DRC_BLOCKS = $(foreach block, $(BLOCKS), drc-$(block))
+$(DRC_BLOCKS): drc-% : ./gds/%.gds
+	echo "Running DRC on $*"
+	mkdir -p ./gds/tmp
+	cd gds && export DESIGN_IN_DRC=$* && export MAGTYPE=mag; magic -rcfile ${PDK_ROOT}/sky130A/libs.tech/magic/current/sky130A.magicrc -noc -dnull drc_on_gds.tcl < /dev/null
+	@echo "DRC result: ./gds/tmp/$*.drc"
+
+# Antenna
+BLOCKS = $(shell cd openlane && find * -maxdepth 0 -type d)
+ANTENNA_BLOCKS = $(foreach block, $(BLOCKS), antenna-$(block))
+$(ANTENNA_BLOCKS): antenna-% : ./gds/%.gds
+	echo "Running Antenna Checks on $*"
+	mkdir -p ./gds/tmp
+	cd gds && export DESIGN_IN_ANTENNA=$* && export MAGTYPE=mag; magic -rcfile ${PDK_ROOT}/sky130A/libs.tech/magic/current/sky130A.magicrc -noc -dnull antenna_on_gds.tcl < /dev/null 2>&1 | tee ./tmp/$*.antenna
+	mv -f ./gds/*.ext ./gds/tmp/
+	@echo "Antenna result: ./gds/tmp/$*.antenna"
+
+.PHONY: help
+help:
+	@$(MAKE) -pRrq -f $(lastword $(MAKEFILE_LIST)) : 2>/dev/null | awk -v RS= -F: '/^# File/,/^# Finished Make data base/ {if ($$1 !~ "^[#.]") {print $$1}}' | sort | egrep -v -e '^[^[:alnum:]]' -e '^$@$$'
+
+
+###########################################################################
+.PHONY: pdk
+pdk: skywater-pdk skywater-library skywater-timing open_pdks build-pdk
+
+$(PDK_ROOT)/skywater-pdk:
+	git clone https://github.com/google/skywater-pdk.git $(PDK_ROOT)/skywater-pdk
+
+.PHONY: skywater-pdk
+skywater-pdk: check-env $(PDK_ROOT)/skywater-pdk
+	cd $(PDK_ROOT)/skywater-pdk && \
+		git checkout master && git pull && \
+		git checkout -qf $(SKYWATER_COMMIT)
+
+.PHONY: skywater-library
+skywater-library: check-env $(PDK_ROOT)/skywater-pdk
+	cd $(PDK_ROOT)/skywater-pdk && \
+		git submodule update --init libraries/$(STD_CELL_LIBRARY)/latest && \
+		git submodule update --init libraries/$(IO_LIBRARY)/latest && \
+		git submodule update --init libraries/$(SPECIAL_VOLTAGE_LIBRARY)/latest
+
+skywater-timing: check-env $(PDK_ROOT)/skywater-pdk
+	cd $(PDK_ROOT)/skywater-pdk && \
+		$(MAKE) -j$(THREADS) timing
+### OPEN_PDKS
+$(PDK_ROOT)/open_pdks:
+	git clone git://opencircuitdesign.com/open_pdks $(PDK_ROOT)/open_pdks
+
+.PHONY: open_pdks
+open_pdks: check-env $(PDK_ROOT)/open_pdks
+	cd $(PDK_ROOT)/open_pdks && \
+		git checkout master && git pull && \
+		git checkout -qf $(OPEN_PDKS_COMMIT)
+
+.PHONY: build-pdk
+build-pdk: check-env $(PDK_ROOT)/open_pdks $(PDK_ROOT)/skywater-pdk
+	[ -d $(PDK_ROOT)/sky130A ] && \
+		(echo "Warning: A sky130A build already exists under $(PDK_ROOT). It will be deleted first!" && \
+		sleep 5 && \
+		rm -rf $(PDK_ROOT)/sky130A) || \
+		true
+	cd $(PDK_ROOT)/open_pdks && \
+		./configure --enable-sky130-pdk=$(PDK_ROOT)/skywater-pdk/libraries --with-sky130-local-path=$(PDK_ROOT) && \
+		cd sky130 && \
+		$(MAKE) veryclean && \
+		$(MAKE) && \
+		$(MAKE) install-local
+
+.RECIPE: manifest
+manifest: mag/ maglef/ verilog/rtl/ scripts/ Makefile
+	touch manifest && \
+	find verilog/rtl/* -type f ! -name "user_*.v" ! -name "manifest" ! -name "README" ! -name "defines.v" -exec shasum {} \; > manifest && \
+	find maglef/*.mag -type f ! -name "user_project_wrapper.mag" -exec shasum {} \; >> manifest && \
+	shasum mag/caravel.mag mag/.magicrc >> manifest
+	shasum scripts/set_user_id.py scripts/generate_fill.py scripts/compositor.py >> manifest
+
+
+check-env:
+ifndef PDK_ROOT
+	$(error PDK_ROOT is undefined, please export it before running make)
+endif
+
+# Make README.rst
+README.rst: README.src.rst docs/source/getting-started.rst docs/source/tool-versioning.rst openlane/README.src.rst docs/source/caravel-with-openlane.rst Makefile
+	pip -q install rst_include && \
+	rm -f README.rst && \
+		rst_include include README.src.rst - | \
+			sed \
+				-e's@\.\/\_static@\/docs\/source\/\_static@g' \
+				-e's@:doc:`tool-versioning`@`tool-versioning.rst <./docs/source/tool-versioning.rst>`__@g' \
+				-e's@.. note::@**NOTE:**@g' \
+				-e's@.. warning::@**WARNING:**@g' \
+				> README.rst && \
+		rst_include include openlane/README.src.rst - | \
+			sed \
+				-e's@https://github.com/efabless/caravel/blob/master/verilog@../verilog@g' \
+				-e's@:ref:`getting-started`@`README.rst <../README.rst>`__@g' \
+				-e's@https://github.com/efabless/caravel/blob/master/openlane/@./@g' \
+				-e's@.. note::@**NOTE:**@g' \
+				-e's@.. warning::@**WARNING:**@g' \
+				> openlane/README.rst
diff --git a/scripts/check_density.py b/scripts/check_density.py
new file mode 100755
index 0000000..7dceb44
--- /dev/null
+++ b/scripts/check_density.py
@@ -0,0 +1,601 @@
+#!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2020 Efabless Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# SPDX-License-Identifier: Apache-2.0
+
+#
+# check_density.py ---
+#
+#    Run density checks on the final (filled) GDS.
+#
+
+import sys
+import os
+import re
+import select
+import subprocess
+
+def usage():
+    print("Usage:")
+    print("check_density.py [<path_to_project>] [-keep]")
+    print("")
+    print("where:")
+    print("   <path_to_project> is the path to the project top level directory.")
+    print("")
+    print("  If <path_to_project> is not given, then it is assumed to be the cwd.")
+    print("  If '-keep' is specified, then keep the check script.")
+    return 0
+
+
+if __name__ == '__main__':
+
+    optionlist = []
+    arguments = []
+
+    debugmode = False
+    keepmode = False
+
+    for option in sys.argv[1:]:
+        if option.find('-', 0) == 0:
+            optionlist.append(option)
+        else:
+            arguments.append(option)
+
+    if len(arguments) > 1:
+        print("Wrong number of arguments given to check_density.py.")
+        usage()
+        sys.exit(0)
+
+    if len(arguments) == 1:
+        user_project_path = arguments[0]
+    else:
+        user_project_path = os.getcwd()
+
+    # Check for valid user path
+
+    if not os.path.isdir(user_project_path):
+        print('Error:  Project path "' + user_project_path + '" does not exist or is not readable.')
+        sys.exit(1)
+
+    # Check for valid user ID
+    user_id_value = None
+    if os.path.isfile(user_project_path + '/info.yaml'):
+        with open(user_project_path + '/info.yaml', 'r') as ifile:
+            infolines = ifile.read().splitlines()
+            for line in infolines:
+                kvpair = line.split(':')
+                if len(kvpair) == 2:
+                    key = kvpair[0].strip()
+                    value = kvpair[1].strip()
+                    if key == 'project_id':
+                        user_id_value = value.strip('"\'')
+                        break
+
+    if user_id_value:
+        project = 'caravel'
+        project_with_id = 'caravel_' + user_id_value
+    else:
+        print('Error:  No project_id found in info.yaml file.')
+        sys.exit(1)
+
+    if '-debug' in optionlist:
+        debugmode = True
+    if '-keep' in optionlist:
+        keepmode = True
+
+    magpath = user_project_path + '/mag'
+    rcfile = magpath + '/.magicrc'
+
+    with open(magpath + '/check_density.tcl', 'w') as ofile:
+        print('#!/bin/env wish', file=ofile)
+        print('crashbackups stop', file=ofile)
+        print('drc off', file=ofile)
+        print('snap internal', file=ofile)
+
+        print('set starttime [orig_clock format [orig_clock seconds] -format "%D %T"]', file=ofile)
+        print('puts stdout "Started reading GDS: $starttime"', file=ofile)
+        print('', file=ofile)
+        print('flush stdout', file=ofile)
+        print('update idletasks', file=ofile)
+
+        # Read final project from .gds
+        print('gds readonly true', file=ofile)
+        print('gds rescale false', file=ofile)
+        print('gds read ../gds/' + project_with_id + '.gds', file=ofile)
+        print('', file=ofile)
+
+        print('set midtime [orig_clock format [orig_clock seconds] -format "%D %T"]', file=ofile)
+        print('puts stdout "Starting density checks: $midtime"', file=ofile)
+        print('', file=ofile)
+        print('flush stdout', file=ofile)
+        print('update idletasks', file=ofile)
+
+        # Get step box dimensions (700um for size and 70um for step)
+        print('box values 0 0 0 0', file=ofile)
+        # print('box size 700um 700um', file=ofile)
+        # print('set stepbox [box values]', file=ofile)
+        # print('set stepwidth [lindex $stepbox 2]', file=ofile)
+        # print('set stepheight [lindex $stepbox 3]', file=ofile)
+
+        print('box size 70um 70um', file=ofile)
+        print('set stepbox [box values]', file=ofile)
+        print('set stepsizex [lindex $stepbox 2]', file=ofile)
+        print('set stepsizey [lindex $stepbox 3]', file=ofile)
+
+        print('select top cell', file=ofile)
+        print('expand', file=ofile)
+        print('set fullbox [box values]', file=ofile)
+        print('set xmax [lindex $fullbox 2]', file=ofile)
+        print('set xmin [lindex $fullbox 0]', file=ofile)
+        print('set fullwidth [expr {$xmax - $xmin}]', file=ofile)
+        print('set xtiles [expr {int(ceil(($fullwidth + 0.0) / $stepsizex))}]', file=ofile)
+        print('set ymax [lindex $fullbox 3]', file=ofile)
+        print('set ymin [lindex $fullbox 1]', file=ofile)
+        print('set fullheight [expr {$ymax - $ymin}]', file=ofile)
+        print('set ytiles [expr {int(ceil(($fullheight + 0.0) / $stepsizey))}]', file=ofile)
+        print('box size $stepsizex $stepsizey', file=ofile)
+        print('set xbase [lindex $fullbox 0]', file=ofile)
+        print('set ybase [lindex $fullbox 1]', file=ofile)
+        print('', file=ofile)
+
+        print('puts stdout "XTILES: $xtiles"', file=ofile)
+        print('puts stdout "YTILES: $ytiles"', file=ofile)
+        print('', file=ofile)
+
+        # Need to know what fraction of a full tile is the last row and column
+        print('set xfrac [expr {($xtiles * $stepsizex - $fullwidth + 0.0) / $stepsizex}]', file=ofile)
+        print('set yfrac [expr {($ytiles * $stepsizey - $fullheight + 0.0) / $stepsizey}]', file=ofile)
+        print('puts stdout "XFRAC: $xfrac"', file=ofile)
+        print('puts stdout "YFRAC: $yfrac"', file=ofile)
+
+        print('cif ostyle density', file=ofile)
+
+        # Process density at steps.  For efficiency, this is done in 70x70 um
+        # areas, dumped to a file, and then aggregated into the 700x700 areas.
+
+        print('for {set y 0} {$y < $ytiles} {incr y} {', file=ofile)
+        print('    for {set x 0} {$x < $xtiles} {incr x} {', file=ofile)
+        print('        set xlo [expr $xbase + $x * $stepsizex]', file=ofile)
+        print('        set ylo [expr $ybase + $y * $stepsizey]', file=ofile)
+        print('        set xhi [expr $xlo + $stepsizex]', file=ofile)
+        print('        set yhi [expr $ylo + $stepsizey]', file=ofile)
+        print('        box values $xlo $ylo $xhi $yhi', file=ofile)
+
+        # Flatten this area
+        print('        flatten -dobbox -nolabels tile', file=ofile)
+        print('        load tile', file=ofile)
+        print('        select top cell', file=ofile)
+
+        # Run density check for each layer
+        print('        puts stdout "Density results for tile x=$x y=$y"', file=ofile)
+
+        print('        set fdens  [cif list cover fom_all]', file=ofile)
+        print('        set pdens  [cif list cover poly_all]', file=ofile)
+        print('        set ldens  [cif list cover li_all]', file=ofile)
+        print('        set m1dens [cif list cover m1_all]', file=ofile)
+        print('        set m2dens [cif list cover m2_all]', file=ofile)
+        print('        set m3dens [cif list cover m3_all]', file=ofile)
+        print('        set m4dens [cif list cover m4_all]', file=ofile)
+        print('        set m5dens [cif list cover m5_all]', file=ofile)
+        print('        puts stdout "FOM: $fdens"', file=ofile)
+        print('        puts stdout "POLY: $pdens"', file=ofile)
+        print('        puts stdout "LI1: $ldens"', file=ofile)
+        print('        puts stdout "MET1: $m1dens"', file=ofile)
+        print('        puts stdout "MET2: $m2dens"', file=ofile)
+        print('        puts stdout "MET3: $m3dens"', file=ofile)
+        print('        puts stdout "MET4: $m4dens"', file=ofile)
+        print('        puts stdout "MET5: $m5dens"', file=ofile)
+        print('        flush stdout', file=ofile)
+        print('        update idletasks', file=ofile)
+
+        print('        load ' + project_with_id, file=ofile)
+        print('        cellname delete tile', file=ofile)
+
+        print('    }', file=ofile)
+        print('}', file=ofile)
+
+        print('set endtime [orig_clock format [orig_clock seconds] -format "%D %T"]', file=ofile)
+        print('puts stdout "Ended: $endtime"', file=ofile)
+        print('', file=ofile)
+
+
+    myenv = os.environ.copy()
+    # Real views are necessary for the DRC checks
+    myenv['MAGTYPE'] = 'mag'
+
+    print('Running density checks on file ' + project_with_id + '.gds', flush=True)
+
+    mproc = subprocess.Popen(['magic', '-dnull', '-noconsole',
+		'-rcfile', rcfile, magpath + '/check_density.tcl'],
+		stdin = subprocess.DEVNULL,
+		stdout = subprocess.PIPE,
+		stderr = subprocess.PIPE,
+		cwd = magpath,
+		env = myenv,
+		universal_newlines = True)
+
+    # Use signal to poll the process and generate any output as it arrives
+
+    dlines = []
+
+    while mproc:
+        status = mproc.poll()
+        if status != None:
+            try:
+                output = mproc.communicate(timeout=1)
+            except ValueError:
+                print('Magic forced stop, status ' + str(status))
+                sys.exit(1)
+            else:
+                outlines = output[0]
+                errlines = output[1]
+                for line in outlines.splitlines():
+                    dlines.append(line)
+                    print(line)
+                for line in errlines.splitlines():
+                    print(line)
+                print('Magic exited with status ' + str(status))
+                if int(status) != 0:
+                    sys.exit(int(status))
+                else:
+                    break
+        else:
+            n = 0
+            while True:
+                n += 1
+                if n > 100:
+                    n = 0
+                    status = mproc.poll()
+                    if status != None:
+                        break
+                sresult = select.select([mproc.stdout, mproc.stderr], [], [], 0)[0]
+                if mproc.stdout in sresult:
+                    outstring = mproc.stdout.readline().strip()
+                    dlines.append(outstring)
+                    print(outstring)
+                elif mproc.stderr in sresult:
+                    outstring = mproc.stderr.readline().strip()
+                    print(outstring)
+                else:
+                    break
+
+    fomfill  = []
+    polyfill = []
+    lifill   = []
+    met1fill = []
+    met2fill = []
+    met3fill = []
+    met4fill = []
+    met5fill = []
+    xtiles = 0
+    ytiles = 0
+    xfrac = 0.0
+    yfrac = 0.0
+
+    for line in dlines:
+        dpair = line.split(':')
+        if len(dpair) == 2:
+            layer = dpair[0]
+            try:
+                density = float(dpair[1].strip())
+            except:
+                continue
+            if layer == 'FOM':
+                fomfill.append(density)
+            elif layer == 'POLY':
+                polyfill.append(density)
+            elif layer == 'LI1':
+                lifill.append(density)
+            elif layer == 'MET1':
+                met1fill.append(density)
+            elif layer == 'MET2':
+                met2fill.append(density)
+            elif layer == 'MET3':
+                met3fill.append(density)
+            elif layer == 'MET4':
+                met4fill.append(density)
+            elif layer == 'MET5':
+                met5fill.append(density)
+            elif layer == 'XTILES':
+                xtiles = int(dpair[1].strip())
+            elif layer == 'YTILES':
+                ytiles = int(dpair[1].strip())
+            elif layer == 'XFRAC':
+                xfrac = float(dpair[1].strip())
+            elif layer == 'YFRAC':
+                yfrac = float(dpair[1].strip())
+
+    if ytiles == 0 or xtiles == 0:
+        print('Failed to read XTILES or YTILES from output.')
+        sys.exit(1)
+
+    total_tiles = (ytiles - 9) * (xtiles - 9)
+
+    print('')
+    print('Density results (total tiles = ' + str(total_tiles) + '):')
+
+    # Full areas are 10 x 10 tiles = 100.  But the right and top sides are
+    # not full tiles, so the full area must be prorated.
+
+    sideadjust = 90.0 + (10.0 * xfrac)
+    topadjust = 90.0 + (10.0 * yfrac)
+    corneradjust = 81.0 + (9.0 * xfrac) + (9.0 * yfrac) + (xfrac * yfrac)
+
+    print('')
+    print('FOM Density:')
+    for y in range(0, ytiles - 9):
+        if y == ytiles - 10:
+            atotal = topadjust
+        else:
+            atotal = 100.0
+        for x in range(0, xtiles - 9):
+            if x == xtiles - 10:
+                if y == ytiles - 10:
+                    atotal = corneradjust
+                else:
+                    atotal = sideadjust
+            fomaccum = 0
+            for w in range(y, y + 10):
+                base = xtiles * w + x
+                fomaccum += sum(fomfill[base : base + 10])
+                    
+            fomaccum /= atotal
+            print('Tile (' + str(x) + ', ' + str(y) + '):   ' + str(fomaccum))
+            if fomaccum < 0.33:
+                print('***Error:  FOM Density < 33%')
+            elif fomaccum > 0.57:
+                print('***Error:  FOM Density > 57%')
+
+    print('')
+    print('POLY Density:')
+    for y in range(0, ytiles - 9):
+        if y == ytiles - 10:
+            atotal = topadjust
+        else:
+            atotal = 100.0
+        for x in range(0, xtiles - 9):
+            if x == xtiles - 10:
+                if y == ytiles - 10:
+                    atotal = corneradjust
+                else:
+                    atotal = sideadjust
+            polyaccum = 0
+            for w in range(y, y + 10):
+                base = xtiles * w + x
+                polyaccum += sum(polyfill[base : base + 10])
+                    
+            polyaccum /= atotal
+            print('Tile (' + str(x) + ', ' + str(y) + '):   ' + str(polyaccum))
+
+    print('')
+    print('LI Density:')
+    for y in range(0, ytiles - 9):
+        if y == ytiles - 10:
+            atotal = topadjust
+        else:
+            atotal = 100.0
+        for x in range(0, xtiles - 9):
+            if x == xtiles - 10:
+                if y == ytiles - 10:
+                    atotal = corneradjust
+                else:
+                    atotal = sideadjust
+            liaccum = 0
+            for w in range(y, y + 10):
+                base = xtiles * w + x
+                liaccum += sum(lifill[base : base + 10])
+                    
+            liaccum /= atotal
+            print('Tile (' + str(x) + ', ' + str(y) + '):   ' + str(liaccum))
+            if liaccum < 0.35:
+                print('***Error:  LI Density < 35%')
+            elif liaccum > 0.70:
+                print('***Error:  LI Density > 70%')
+
+    print('')
+    print('MET1 Density:')
+    for y in range(0, ytiles - 9):
+        if y == ytiles - 10:
+            atotal = topadjust
+        else:
+            atotal = 100.0
+        for x in range(0, xtiles - 9):
+            if x == xtiles - 10:
+                if y == ytiles - 10:
+                    atotal = corneradjust
+                else:
+                    atotal = sideadjust
+            met1accum = 0
+            for w in range(y, y + 10):
+                base = xtiles * w + x
+                met1accum += sum(met1fill[base : base + 10])
+                    
+            met1accum /= atotal
+            print('Tile (' + str(x) + ', ' + str(y) + '):   ' + str(met1accum))
+            if met1accum < 0.35:
+                print('***Error:  MET1 Density < 35%')
+            elif met1accum > 0.70:
+                print('***Error:  MET1 Density > 70%')
+
+    print('')
+    print('MET2 Density:')
+    for y in range(0, ytiles - 9):
+        if y == ytiles - 10:
+            atotal = topadjust
+        else:
+            atotal = 100.0
+        for x in range(0, xtiles - 9):
+            if x == xtiles - 10:
+                if y == ytiles - 10:
+                    atotal = corneradjust
+                else:
+                    atotal = sideadjust
+            met2accum = 0
+            for w in range(y, y + 10):
+                base = xtiles * w + x
+                met2accum += sum(met2fill[base : base + 10])
+                    
+            met2accum /= atotal
+            print('Tile (' + str(x) + ', ' + str(y) + '):   ' + str(met2accum))
+            if met2accum < 0.35:
+                print('***Error:  MET2 Density < 35%')
+            elif met2accum > 0.70:
+                print('***Error:  MET2 Density > 70%')
+
+    print('')
+    print('MET3 Density:')
+    for y in range(0, ytiles - 9):
+        if y == ytiles - 10:
+            atotal = topadjust
+        else:
+            atotal = 100.0
+        for x in range(0, xtiles - 9):
+            if x == xtiles - 10:
+                if y == ytiles - 10:
+                    atotal = corneradjust
+                else:
+                    atotal = sideadjust
+            met3accum = 0
+            for w in range(y, y + 10):
+                base = xtiles * w + x
+                met3accum += sum(met3fill[base : base + 10])
+                    
+            met3accum /= atotal
+            print('Tile (' + str(x) + ', ' + str(y) + '):   ' + str(met3accum))
+            if met3accum < 0.35:
+                print('***Error:  MET3 Density < 35%')
+            elif met3accum > 0.70:
+                print('***Error:  MET3 Density > 70%')
+
+    print('')
+    print('MET4 Density:')
+    for y in range(0, ytiles - 9):
+        if y == ytiles - 10:
+            atotal = topadjust
+        else:
+            atotal = 100.0
+        for x in range(0, xtiles - 9):
+            if x == xtiles - 10:
+                if y == ytiles - 10:
+                    atotal = corneradjust
+                else:
+                    atotal = sideadjust
+            met4accum = 0
+            for w in range(y, y + 10):
+                base = xtiles * w + x
+                met4accum += sum(met4fill[base : base + 10])
+                    
+            met4accum /= atotal
+            print('Tile (' + str(x) + ', ' + str(y) + '):   ' + str(met4accum))
+            if met4accum < 0.35:
+                print('***Error:  MET4 Density < 35%')
+            elif met4accum > 0.70:
+                print('***Error:  MET4 Density > 70%')
+
+    print('')
+    print('MET5 Density:')
+    for y in range(0, ytiles - 9):
+        if y == ytiles - 10:
+            atotal = topadjust
+        else:
+            atotal = 100.0
+        for x in range(0, xtiles - 9):
+            if x == xtiles - 10:
+                if y == ytiles - 10:
+                    atotal = corneradjust
+                else:
+                    atotal = sideadjust
+            met5accum = 0
+            for w in range(y, y + 10):
+                base = xtiles * w + x
+                met5accum += sum(met5fill[base : base + 10])
+                    
+            met5accum /= atotal
+            print('Tile (' + str(x) + ', ' + str(y) + '):   ' + str(met5accum))
+            if met5accum < 0.45:
+                print('***Error:  MET5 Density < 45%')
+            elif met5accum > 0.86:
+                print('***Error:  MET5 Density > 86%')
+
+    print('')
+    print('Whole-chip density results:')
+
+    atotal = ((xtiles - 1.0) * (ytiles - 1.0)) + ((ytiles - 1.0) * xfrac) + ((xtiles - 1.0) * yfrac) + (xfrac * yfrac)
+
+    fomaccum = sum(fomfill) / atotal
+    print('')
+    print('FOM Density: ' + str(fomaccum))
+    if fomaccum < 0.33:
+        print('***Error:  FOM Density < 33%')
+    elif fomaccum > 0.57:
+        print('***Error:  FOM Density > 57%')
+
+    polyaccum = sum(polyfill) / atotal
+    print('')
+    print('POLY Density: ' + str(polyaccum))
+
+    liaccum = sum(lifill) / atotal
+    print('')
+    print('LI Density: ' + str(liaccum))
+    if liaccum < 0.35:
+        print('***Error:  LI Density < 35%')
+    elif liaccum > 0.70:
+        print('***Error:  LI Density > 70%')
+
+    met1accum = sum(met1fill) / atotal
+    print('')
+    print('MET1 Density: ' + str(met1accum))
+    if met1accum < 0.35:
+        print('***Error:  MET1 Density < 35%')
+    elif met1accum > 0.70:
+        print('***Error:  MET1 Density > 70%')
+
+    met2accum = sum(met2fill) / atotal
+    print('')
+    print('MET2 Density: ' + str(met2accum))
+    if met2accum < 0.35:
+        print('***Error:  MET2 Density < 35%')
+    elif met2accum > 0.70:
+        print('***Error:  MET2 Density > 70%')
+
+    met3accum = sum(met3fill) / atotal
+    print('')
+    print('MET3 Density: ' + str(met3accum))
+    if met3accum < 0.35:
+        print('***Error:  MET3 Density < 35%')
+    elif met3accum > 0.70:
+        print('***Error:  MET3 Density > 70%')
+
+    met4accum = sum(met4fill) / atotal
+    print('')
+    print('MET4 Density: ' + str(met4accum))
+    if met4accum < 0.35:
+        print('***Error:  MET4 Density < 35%')
+    elif met4accum > 0.70:
+        print('***Error:  MET4 Density > 70%')
+
+    met5accum = sum(met5fill) / atotal
+    print('')
+    print('MET5 Density: ' + str(met5accum))
+    if met5accum < 0.45:
+        print('***Error:  MET5 Density < 45%')
+    elif met5accum > 0.86:
+        print('***Error:  MET5 Density > 86%')
+
+    if not keepmode:
+        os.remove(magpath + '/check_density.tcl')
+
+    print('')
+    print('Done!')
+    sys.exit(0)
diff --git a/scripts/count_lvs.py b/scripts/count_lvs.py
new file mode 100644
index 0000000..21b7771
--- /dev/null
+++ b/scripts/count_lvs.py
@@ -0,0 +1,132 @@
+#!/usr/bin/python3
+# SPDX-FileCopyrightText: 2020 Efabless Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# SPDX-License-Identifier: Apache-2.0
+
+#
+#---------------------------------------------------------
+# LVS failure check
+#
+# This is a Python script that parses the comp.json
+# output from netgen and reports on the number of
+# errors in the top-level netlist.
+#
+#---------------------------------------------------------
+# Written by Tim Edwards
+# efabless, inc.
+# Pulled from qflow GUI as standalone script Aug 20, 2018
+#---------------------------------------------------------
+
+import os
+import re
+import sys
+import json
+import argparse
+
+def count_LVS_failures(filename):
+    with open(filename, 'r') as cfile:
+        lvsdata = json.load(cfile)
+
+    # Count errors in the JSON file
+    failures = 0
+    devfail = 0
+    netfail = 0
+    pinfail = 0
+    propfail = 0
+    netdiff = 0
+    devdiff = 0
+    ncells = len(lvsdata)
+    for c in range(0, ncells):
+        cellrec = lvsdata[c]
+
+        if c == ncells - 1:
+            topcell = True
+        else:
+            topcell = False
+
+        # Most errors must only be counted for the top cell, because individual
+        # failing cells are flattened and the matching attempted again on the
+        # flattened netlist.
+
+        if topcell:
+            if 'devices' in cellrec:
+                devices = cellrec['devices']
+                devlist = [val for pair in zip(devices[0], devices[1]) for val in pair]
+                devpair = list(devlist[p:p + 2] for p in range(0, len(devlist), 2))
+                for dev in devpair:
+                    c1dev = dev[0]
+                    c2dev = dev[1]
+                    diffdevs = abs(c1dev[1] - c2dev[1])
+                    failures += diffdevs
+                    devdiff += diffdevs
+
+            if 'nets' in cellrec:
+                nets = cellrec['nets']
+                diffnets = abs(nets[0] - nets[1])
+                failures += diffnets
+                netdiff += diffnets
+
+            if 'badnets' in cellrec:
+                badnets = cellrec['badnets']
+                failures += len(badnets)
+                netfail += len(badnets)
+
+            if 'badelements' in cellrec:
+                badelements = cellrec['badelements']
+                failures += len(badelements)
+                devfail += len(badelements)
+
+            if 'pins' in cellrec:
+                pins = cellrec['pins']
+                pinlist = [val for pair in zip(pins[0], pins[1]) for val in pair]
+                pinpair = list(pinlist[p:p + 2] for p in range(0, len(pinlist), 2))
+                for pin in pinpair:
+                    # Avoid flagging global vs. local names, e.g., "gnd" vs. "gnd!,"
+                    # and ignore case when comparing pins.
+                    pin0 = re.sub('!$', '', pin[0].lower())
+                    pin1 = re.sub('!$', '', pin[1].lower())
+                    if pin0 != pin1:
+                        failures += 1
+                        pinfail += 1
+
+        # Property errors must be counted for every cell
+        if 'properties' in cellrec:
+            properties = cellrec['properties']
+            failures += len(properties)
+            propfail += len(properties)
+
+    return [failures, netfail, devfail, pinfail, propfail, netdiff, devdiff]
+
+if __name__ == '__main__':
+
+    parser = argparse.ArgumentParser(description='Parses netgen lvs')
+    parser.add_argument('--file', '-f', required=True)
+    args = parser.parse_args()
+    failures = count_LVS_failures(args.file)
+    total = failures[0]
+    if total > 0:
+        failed = True
+        print('LVS reports:')
+        print('    net count difference = ' + str(failures[5]))
+        print('    device count difference = ' + str(failures[6]))
+        print('    unmatched nets = ' + str(failures[1]))
+        print('    unmatched devices = ' + str(failures[2]))
+        print('    unmatched pins = ' + str(failures[3]))
+        print('    property failures = ' + str(failures[4]))
+    else:
+        print('LVS reports no net, device, pin, or property mismatches.')
+
+    print('')
+    print('Total errors = ' + str(total))
+ 
diff --git a/scripts/create-caravel-diagram.py b/scripts/create-caravel-diagram.py
new file mode 100644
index 0000000..18af64d
--- /dev/null
+++ b/scripts/create-caravel-diagram.py
@@ -0,0 +1,112 @@
+import sys
+import os
+import subprocess
+from pathlib import Path
+import argparse
+from tempfile import mkstemp
+import re
+
+
+def remove_inouts(jsonpath, replacewith='input'):
+    """Replaces inouts with either input or output statements.
+
+    Netlistsvg does not parse inout ports as for now, so they need to be
+    replaced with either input or output to produce a diagram.
+
+    Parameters
+    ----------
+    jsonpath : str
+        Path to JSON file to fix
+    replacewith : str
+        The string to replace 'inout', can be 'input' or 'output'
+    """
+    assert replacewith in ['input', 'output']
+    with open(jsonpath, 'r') as withinouts:
+        lines = withinouts.readlines()
+    with open(jsonpath, 'w') as withoutinouts:
+        for line in lines:
+            withoutinouts.write(re.sub('inout', replacewith, line))
+
+
+def main(argv):
+    parser = argparse.ArgumentParser(argv[0])
+    parser.add_argument(
+        'verilog_rtl_dir',
+        help="Path to the project's verilog/rtl directory",
+        type=Path)
+    parser.add_argument(
+        'output',
+        help="Path to the output SVG file",
+        type=Path)
+    parser.add_argument(
+        '--num-iopads',
+        help='Number of iopads to render',
+        type=int,
+        default=38)
+    parser.add_argument(
+        '--yosys-executable',
+        help='Path to yosys executable',
+        type=Path,
+        default='yosys')
+    parser.add_argument(
+        '--netlistsvg-executable',
+        help='Path to netlistsvg executable',
+        type=Path,
+        default='netlistsvg')
+    parser.add_argument(
+        '--inouts-as',
+        help='To what kind of IO should inout ports be replaced',
+        choices=['input', 'output'],
+        default='input'
+    )
+
+    args = parser.parse_args(argv[1:])
+
+    fd, jsonpath = mkstemp(suffix='-yosys.json')
+    os.close(fd)
+
+    yosyscommand = [
+        f'{str(args.yosys_executable)}',
+        '-p',
+        'read_verilog pads.v defines.v; ' +
+        'read_verilog -lib -overwrite *.v; ' +
+        f'verilog_defines -DMPRJ_IO_PADS={args.num_iopads}; ' +
+        'read_verilog -overwrite caravel.v; ' +
+        'hierarchy -top caravel; ' +
+        'proc; ' +
+        'opt; ' +
+        f'write_json {jsonpath}; '
+    ]
+
+    result = subprocess.run(
+        yosyscommand,
+        cwd=args.verilog_rtl_dir,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.STDOUT
+    )
+
+    exitcode = 0
+    if result.returncode != 0:
+        print(f'Failed to run: {" ".join(yosyscommand)}', file=sys.stderr)
+        print(result.stdout.decode())
+        exitcode = result.returncode
+    else:
+        # TODO once netlistsvg supports inout ports, this should be removed
+        remove_inouts(jsonpath, args.inouts_as)
+        command = f'{args.netlistsvg_executable} {jsonpath} -o {args.output}'
+        result = subprocess.run(
+            command.split(),
+            stdout=subprocess.PIPE,
+            stderr=subprocess.STDOUT
+        )
+        if result.returncode != 0:
+            print(f'Failed to run: {command}', file=sys.stderr)
+            print(result.stdout.decode())
+            exitcode = result.returncode
+
+    os.unlink(jsonpath)
+    sys.exit(exitcode)
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv))