iic-pex.sh

#!/bin/bash
# ========================================================================
# PEX (Parasitic Extraction) using Magic VLSI
#
# SPDX-FileCopyrightText: 2021-2024 Harald Pretl
# Johannes Kepler University, Institute for Integrated Circuits
#
# 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
#
# Usage: iic-pex.sh [-d] [-m mode] [-s mode] [-n <subcktname>] [-w <workdir>] <cellname>
#
# Supported PEX modes:
#   1 = C-decoupled
#   2 = C-coupled (default)
#   3 = full-RC
# ========================================================================

ERR_GENERAL=1
ERR_FILE_NOT_FOUND=2
ERR_NO_PARAM=3
ERR_WRONG_MODE=4
ERR_CMD_NOT_FOUND=5
ERR_PDK_NOT_SUPPORTED=6

if [ $# -eq 0 ]; then
	echo
	echo "PEX script using Magic-VLSI (IIC@JKU)"
	echo
	echo "Usage: $0 [-d] [-m mode] [-s mode] [-n <subcktname>] [-w <workdir>] <cellname>"
	echo
	echo "       -m Select PEX mode (1 = C-decoupled, 2 = C-coupled [default], 3 = full-RC)"
	echo "       -s Subcircuit definition in PEX netlist (1 = include subcircuit definition [default], 0 = no subcircuit)"
	echo "       -n name of PEX subcircuit (default is <cellname>)"
	echo "       -w Set <workdir> working directory"
	echo "       -d Enable debug information"
	echo
	exit $ERR_NO_PARAM
fi

# Set the default behavior
# ------------------------

DEBUG=0
GDS_MODE=0
EXT_MODE=2
SUBCIRCUIT=1
RESDIR=$PWD
CELL_NAME_SET=0

# Check flags
# -----------

while getopts "m:s:w:n:d" flag; do
	case $flag in
		m)
			[ $DEBUG -eq 1 ] && echo "[INFO] Flag -m is set to <$OPTARG>."
			EXT_MODE=${OPTARG}
			;;
		s)
			[ $DEBUG -eq 1 ] && echo "[INFO] Flag -s is set to <$OPTARG>."
			SUBCIRCUIT=${OPTARG}
			;;
		w)
			[ $DEBUG -eq 1 ] && echo "[INFO] Flag -w is set to <$OPTARG>."
			RESDIR=$(realpath "$OPTARG")
			;;
		n)
			[ $DEBUG -eq 1 ] && echo "[INFO] Flag -n is set to <$OPTARG>."
			CELL_NAME_SET=1
			CELL_NAME_PEX=${OPTARG}
			;;	
		d)
			echo "[INFO] DEBUG is enabled."
			DEBUG=1
			;;
		*)
			;;
    esac
done
shift $((OPTIND-1))

# Check that the mode is an integer and in a valid range
# ------------------------------------------------------

if [ -n "$EXT_MODE" ] && [ "$EXT_MODE" -eq "$EXT_MODE" ] 2>/dev/null; then
	if [ "$EXT_MODE" -lt 1 ] || [ "$EXT_MODE" -gt 3 ]; then
        echo "[ERROR] Unknown extraction mode!"
        exit $ERR_WRONG_MODE
	fi
else
        echo "[ERROR] Extraction mode must be an integer!"
        exit $ERR_WRONG_MODE
fi

if [ -n "$SUBCIRCUIT" ] && [ "$SUBCIRCUIT" -eq "$SUBCIRCUIT" ] 2>/dev/null; then
	if [ "$SUBCIRCUIT" -lt 0 ] || [ "$SUBCIRCUIT" -gt 1 ]; then
        echo "[ERROR] Illegal subcircuit mode!"
        exit $ERR_WRONG_MODE
	fi
else
        echo "[ERROR] Subcircuit mode must be an integer!"
        exit $ERR_WRONG_MODE
fi

# Check if the PDK is already supported by this script
# ----------------------------------------------------

if echo "$PDK" | grep -q -i "sky130"; then
	[ $DEBUG -eq 1 ] && echo "[INFO] sky130 PDK selected"
elif echo "$PDK" | grep -q -i "gf180mcuC"; then
	[ $DEBUG -eq 1 ] && echo "[INFO] gf180mcuC PDK selected"
else
	echo "[ERROR] The PDK $PDK is not yet supported!"
	exit $ERR_PDK_NOT_SUPPORTED
fi

# check if the input file exists
# ------------------------------

if [ -z "$1" ]; then
	echo "[ERROR] No cellname provided!"
	exit $ERR_FILE_NOT_FOUND
elif [ -f "$1" ]; then
	CELL_LAY="$1"
elif [ -f "$1.mag" ]; then
	CELL_LAY="$1.mag"
elif [ -f "$1.mag.gz" ]; then
	CELL_LAY="$1.mag.gz"
elif [ -f "$1.gds" ]; then
	CELL_LAY="$1.gds"
	GDS_MODE=1
elif [ -f "$1.gds.gz" ]; then
	CELL_LAY="$1.gds.gz"
	GDS_MODE=1
else
	echo "[ERROR] Layout $CELL_LAY not found!"
    exit $ERR_FILE_NOT_FOUND
fi

[ $DEBUG -eq 1 ] && echo "[INFO] CELL_LAY=$CELL_LAY"

# Define useful variables
# -----------------------

CELL_NAME=$(basename "$CELL_LAY" | cut -f 1 -d '.')
EXT_SCRIPT="$RESDIR/pex_$CELL_NAME.tcl"
NETLIST_PEX="$RESDIR/$CELL_NAME.pex.spice"
if [ $CELL_NAME_SET -eq 0 ]; then
	CELL_NAME_PEX=${CELL_NAME}
fi

# check if GDS file
# -----------------

if [[ "$CELL_LAY" == *"gds.gz" ]]; then
	cp "$CELL_LAY" tmp.gds.gz
	[ -f tmp.gds ] && rm -f tmp.gds
	gunzip tmp.gds.gz > /dev/null
	CELL_LAY="tmp.gds"
fi
if [[ "$CELL_LAY" == *"gds" ]]; then
	GDS_MODE=1
	[ $DEBUG = 1 ] && echo "[INFO] GDS mode is selected."	
fi

# Generate extract script for magic
# ---------------------------------

{
	echo "crashbackups stop"
	echo "drc off"
} > "$EXT_SCRIPT"

if [ "$GDS_MODE" -eq 0 ]; then
	# we read a .mag/.mag.gz view
	{
		echo "load ${CELL_LAY}"
	} >> "$EXT_SCRIPT"
else
	# we read a .gds/.gds.gz view
	{
		echo "gds read ${CELL_LAY}"
		echo "load ${CELL_NAME}"
	} >> "$EXT_SCRIPT"
fi

{
	echo "select top cell"
	echo "flatten ${CELL_NAME}_flat"
	echo "load ${CELL_NAME}_flat"
	echo "cellname delete ${CELL_NAME}"
	echo "cellname rename ${CELL_NAME}_flat ${CELL_NAME_PEX}"
	echo "select top cell"
	echo "extract path $RESDIR"
	echo "ext2spice lvs"
} >> "$EXT_SCRIPT"

if [ "$EXT_MODE" -eq 1 ] || [ "$EXT_MODE" -eq 2 ]; then
	if [ "$EXT_MODE" -eq 1 ]; then
		EXT_MODE_TEXT="C-decoupled"
	elif [ "$EXT_MODE" -eq 2 ]; then
		EXT_MODE_TEXT="C-coupled"
	else
		echo "[ERROR] Illegal branch!"
		exit $ERR_GENERAL
	fi
	
	{
		[ "$EXT_MODE" -eq 1 ] && echo "extract no coupling"
		echo "extract all"
	} >> "$EXT_SCRIPT"
fi

if [ "$EXT_MODE" -eq 3 ]; then
	# Extraction mode RC
	EXT_MODE_TEXT="full-RC"
	{
		echo "extract do resistance"
		echo "extract all"
		echo "ext2sim labels on"
		echo "ext2sim"
		echo "extresist tolerance 10"
		echo "extresist all"
		echo "ext2spice extresist on"
		# FIXME acc. Tim Edwards the "tee on" option might produce wrong netlists by placing resistors twice.
		# Need to experiment with it!
		# echo "ext2spice resistor tee on"
	} >> "$EXT_SCRIPT"
fi

{
	echo "ext2spice cthresh 0.01"	
	[ "$SUBCIRCUIT" -eq 0 ] && echo "ext2spice subcircuit top off"
	echo "ext2spice -p $RESDIR -o $NETLIST_PEX.tmp"
	echo "quit -noprompt"
} >> "$EXT_SCRIPT"

# check if commands exist in the path
# -----------------------------------

if [ ! -x "$(command -v magic)" ]; then
   	echo "[ERROR] magic could not be found!"
   	exit $ERR_CMD_NOT_FOUND
fi

# Extract SPICE netlist from layout with magic
# --------------------------------------------
echo "[INFO] Running PEX using magic..."

if [ $DEBUG -eq 0 ]; then
	magic -dnull -noconsole \
		-rcfile "$PDKPATH/libs.tech/magic/$PDK.magicrc" \
		"$EXT_SCRIPT" "$NO_MESSAGE" \
		> /dev/null 2> /dev/null
else
	magic -dnull -noconsole \
		-rcfile "$PDKPATH/libs.tech/magic/$PDK.magicrc" \
		"$EXT_SCRIPT" "$NO_MESSAGE"
fi

if [ ! -f "$NETLIST_PEX.tmp" ]; then
	echo "[ERROR] No PEX file produced, something went wrong!"
	exit $ERR_GENERAL
else
	DATE=$(date)
	HEADER="* PEX produced on $DATE using $0 with m=$EXT_MODE and s=$SUBCIRCUIT"
	{
		echo "$HEADER"
		cat "$NETLIST_PEX.tmp"	
	} > "$NETLIST_PEX"
	rm -f "$NETLIST_PEX.tmp"

	sed -i 's/_flat//g' "$NETLIST_PEX"
fi 

# Cleanup
# -------
rm -f ./*.ext
[ -f tmp.gds ] && rm -f tmp.gds
if [ "$EXT_MODE" -eq 3 ]; then
	rm -f ./*.nodes
	rm -f ./*.ext
	rm -f ./*.sim
	rm -f ./*.res.ext
fi
[ $DEBUG -eq 0 ] && rm -f "$EXT_SCRIPT"

# Finished
# --------
echo "[DONE] PEX ($EXT_MODE_TEXT) done, extracted SPICE netlist is <$NETLIST_PEX>."