OpenRAM/compiler/router/supply_tree_router.py

209 lines
8.6 KiB
Python

# See LICENSE for licensing information.
#
# Copyright (c) 2016-2023 Regents of the University of California and The Board
# of Regents for the Oklahoma Agricultural and Mechanical College
# (acting for and on behalf of Oklahoma State University)
# All rights reserved.
#
from datetime import datetime
from scipy.sparse import csr_matrix
from scipy.sparse.csgraph import minimum_spanning_tree
from openram import debug
from openram import print_time
from .router import router
from . import grid_utils
from .signal_grid import signal_grid
class supply_tree_router(router):
"""
A router class to read an obstruction map from a gds and
routes a grid to connect the supply on the two layers.
"""
def __init__(self, layers, design, bbox=None, pin_type=None):
"""
This will route on layers in design. It will get the blockages from
either the gds file name or the design itself (by saving to a gds file).
"""
# Power rail width in minimum wire widths
# This is set to match the signal router so that the grids are aligned
# for prettier routes.
self.route_track_width = 1
# The pin escape router already made the bounding box big enough,
# so we can use the regular bbox here.
if pin_type:
debug.check(pin_type in ["left", "right", "top", "bottom", "single", "ring"],
"Invalid pin type {}".format(pin_type))
self.pin_type = pin_type
router.__init__(self,
layers,
design,
bbox=bbox,
route_track_width=self.route_track_width)
def route(self, vdd_name="vdd", gnd_name="gnd"):
"""
Route the two nets in a single layer.
Setting pin stripe will make a power rail on the left side.
"""
debug.info(1, "Running supply router on {0} and {1}...".format(vdd_name, gnd_name))
self.vdd_name = vdd_name
self.gnd_name = gnd_name
# Clear the pins if we have previously routed
if (hasattr(self, 'rg')):
self.clear_pins()
else:
# Creat a routing grid over the entire area
# FIXME: This could be created only over the routing region,
# but this is simplest for now.
self.create_routing_grid(signal_grid)
start_time = datetime.now()
# Get the pin shapes
self.find_pins_and_blockages([self.vdd_name, self.gnd_name])
print_time("Finding pins and blockages", datetime.now(), start_time, 3)
# Add side pins if enabled
if self.pin_type in ["left", "right", "top", "bottom"]:
self.add_side_supply_pin(self.vdd_name, side=self.pin_type)
self.add_side_supply_pin(self.gnd_name, side=self.pin_type)
elif self.pin_type == "ring":
self.add_ring_supply_pin(self.vdd_name)
self.add_ring_supply_pin(self.gnd_name)
#self.write_debug_gds("initial_tree_router.gds",False)
#breakpoint()
# Route the supply pins to the supply rails
# Route vdd first since we want it to be shorter
start_time = datetime.now()
self.route_pins(vdd_name)
self.route_pins(gnd_name)
print_time("Maze routing supplies", datetime.now(), start_time, 3)
# Did we route everything??
if not self.check_all_routed(vdd_name):
return False
if not self.check_all_routed(gnd_name):
return False
return True
def route_pins(self, pin_name):
"""
This will route each of the remaining pin components to the other pins.
After it is done, the cells are added to the pin blockage list.
"""
remaining_components = sum(not x.is_routed() for x in self.pin_groups[pin_name])
debug.info(1, "Routing {0} with {1} pins.".format(pin_name,
remaining_components))
# Save pin center locations
if False:
debug.info(2, "Creating location file {0}_{1}.csv".format(self.cell.name, pin_name))
f = open("{0}_{1}.csv".format(self.cell.name, pin_name), "w")
pin_size = len(self.pin_groups[pin_name])
for index1, pg1 in enumerate(self.pin_groups[pin_name]):
location = list(pg1.grids)[0]
f.write("{0},{1},{2}\n".format(location.x, location.y, location.z))
f.close()
# Create full graph
debug.info(2, "Creating adjacency matrix")
pin_size = len(self.pin_groups[pin_name])
adj_matrix = [[0] * pin_size for i in range(pin_size)]
for index1, pg1 in enumerate(self.pin_groups[pin_name]):
for index2, pg2 in enumerate(self.pin_groups[pin_name]):
if index1>=index2:
continue
dist = int(grid_utils.distance_set(list(pg1.grids)[0], pg2.grids))
adj_matrix[index1][index2] = dist
# Find MST
debug.info(2, "Finding Minimum Spanning Tree")
X = csr_matrix(adj_matrix)
from scipy.sparse import save_npz
#print("Saving {}.npz".format(self.cell.name))
#save_npz("{}.npz".format(self.cell.name), X)
#exit(1)
Tcsr = minimum_spanning_tree(X)
mst = Tcsr.toarray().astype(int)
connections = []
for x in range(pin_size):
for y in range(pin_size):
if x >= y:
continue
if mst[x][y]>0:
connections.append((x, y))
# Route MST components
level=99
for index, (src, dest) in enumerate(connections):
if not (index % 25):
debug.info(1, "{0} supply segments routed, {1} remaining.".format(index, len(connections) - index))
self.route_signal(pin_name, src, dest)
if False and pin_name == "gnd":
debug.info(level, "\nSRC {}: ".format(src) + str(self.pin_groups[pin_name][src].grids) + str(self.pin_groups[pin_name][src].blockages))
debug.info(level, ("DST {}: ".format(dest) + str(self.pin_groups[pin_name][dest].grids) + str(self.pin_groups[pin_name][dest].blockages)))
self.write_debug_gds("post_{0}_{1}.gds".format(src, dest), False)
#self.write_debug_gds("final_tree_router_{}.gds".format(pin_name), False)
#return
def route_signal(self, pin_name, src_idx, dest_idx):
# First pass, try to route normally
# Second pass, clear prior pin blockages so that you can route over other metal
# of the same supply. Otherwise, this can create a lot of circular routes due to accidental overlaps.
for unblock_routes in [False, True]:
for detour_scale in [2 * pow(2, x) for x in range(5)]:
debug.info(2, "Routing {0} to {1} with scale {2}".format(src_idx, dest_idx, detour_scale))
# Clear everything in the routing grid.
self.rg.reinit()
# This is inefficient since it is non-incremental, but it was
# easier to debug.
self.prepare_blockages(src=(pin_name, src_idx), dest=(pin_name, dest_idx))
if unblock_routes:
msg = "Unblocking supply self blockages to improve access (may cause DRC errors):\n{0}\n{1})"
debug.warning(msg.format(pin_name,
self.pin_groups[pin_name][src_idx].pins))
self.set_blockages(self.path_blockages, False)
# Add the single component of the pin as the source
# which unmarks it as a blockage too
self.set_pin_component_source(pin_name, src_idx)
# Marks all pin components except index as target
# which unmarks it as a blockage too
self.set_pin_component_target(pin_name, dest_idx)
# Actually run the A* router
if self.run_router(detour_scale=detour_scale):
return
#if detour_scale > 2:
# self.write_debug_gds("route_{0}_{1}_d{2}.gds".format(src_idx, dest_idx, detour_scale), False)
self.write_debug_gds("debug_route.gds", True)
def add_io_pin(self, instance, pin_name, new_name=""):
"""
Add a signle input or output pin up to metal 3.
"""
pin = instance.get_pins(pin_name)
if new_name == "":
new_name = pin_name
# Just use the power pin function for now to save code
self.add_power_pin(name=new_name, loc=pin.center(), start_layer=pin.layer)