Split graph router class to use it for signal escaping later

This commit is contained in:
Eren Dogan 2023-07-31 19:43:09 -07:00
parent 7be6f2783b
commit db2a276077
4 changed files with 302 additions and 282 deletions

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@ -260,7 +260,7 @@ class sram_1bank(design, verilog, lef):
elif OPTS.route_supplies == "tree": elif OPTS.route_supplies == "tree":
from openram.router import supply_tree_router as router from openram.router import supply_tree_router as router
else: else:
from openram.router import graph_router as router from openram.router import supply_graph_router as router
rtr=router(layers=self.supply_stack, rtr=router(layers=self.supply_stack,
design=self, design=self,
bbox=bbox, bbox=bbox,

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@ -8,4 +8,4 @@ from .signal_escape_router import *
from .signal_router import * from .signal_router import *
from .supply_grid_router import * from .supply_grid_router import *
from .supply_tree_router import * from .supply_tree_router import *
from .graph_router import * from .supply_graph_router import *

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@ -5,25 +5,22 @@
# #
from openram import debug from openram import debug
from openram.base.vector import vector from openram.base.vector import vector
from openram.base.vector3d import vector3d
from openram.gdsMill import gdsMill from openram.gdsMill import gdsMill
from openram.tech import GDS from openram.tech import GDS
from openram.tech import drc from openram.tech import drc
from openram.tech import layer as tech_layer from openram.tech import layer as tech_layer
from openram import OPTS from openram import OPTS
from .router_tech import router_tech from .router_tech import router_tech
from .graph import graph
from .graph_shape import graph_shape from .graph_shape import graph_shape
from .graph_utils import snap from .graph_utils import snap
class graph_router(router_tech): class graph_router(router_tech):
""" """
This is the router class that uses the Hanan grid method to route pins using This is the base class for routers that use the Hanan grid graph method.
a graph.
""" """
def __init__(self, layers, design, bbox=None, pin_type=None): def __init__(self, layers, design, bbox=None):
# `router_tech` contains tech constants for the router # `router_tech` contains tech constants for the router
router_tech.__init__(self, layers, route_track_width=1) router_tech.__init__(self, layers, route_track_width=1)
@ -32,9 +29,6 @@ class graph_router(router_tech):
self.layers = layers self.layers = layers
# This is the `hierarchy_layout` object # This is the `hierarchy_layout` object
self.design = design self.design = design
# Side supply pin type
# (can be "top", "bottom", "right", "left", and "ring")
self.pin_type = pin_type
# Temporary GDSII file name to find pins and blockages # Temporary GDSII file name to find pins and blockages
self.gds_filename = OPTS.openram_temp + "temp.gds" self.gds_filename = OPTS.openram_temp + "temp.gds"
# Dictionary for vdd and gnd pins # Dictionary for vdd and gnd pins
@ -46,8 +40,6 @@ class graph_router(router_tech):
self.blockages = [] self.blockages = []
# This is all the vias between routing layers # This is all the vias between routing layers
self.vias = [] self.vias = []
# New pins are the side supply pins
self.new_pins = {}
# Fake pins are imaginary pins on the side supply pins to route other # Fake pins are imaginary pins on the side supply pins to route other
# pins to them # pins to them
self.fake_pins = [] self.fake_pins = []
@ -56,81 +48,6 @@ class graph_router(router_tech):
self.offset = snap(self.track_wire / 2) self.offset = snap(self.track_wire / 2)
def route(self, vdd_name="vdd", gnd_name="gnd"):
""" Route the given pins in the given order. """
debug.info(1, "Running router for {} and {}...".format(vdd_name, gnd_name))
# Save pin names
self.vdd_name = vdd_name
self.gnd_name = gnd_name
# Prepare gdsMill to find pins and blockages
self.prepare_gds_reader()
# Find pins to be routed
self.find_pins(vdd_name)
self.find_pins(gnd_name)
# Find blockages and vias
self.find_blockages()
self.find_vias()
# Convert blockages and vias if they overlap a pin
self.convert_vias()
self.convert_blockages()
# Add side pins
self.calculate_ring_bbox()
if self.pin_type in ["top", "bottom", "right", "left"]:
self.add_side_pin(vdd_name)
self.add_side_pin(gnd_name)
elif self.pin_type == "ring":
self.add_ring_pin(vdd_name)
self.add_ring_pin(gnd_name)
else:
debug.warning("Side supply pins aren't created.")
# Add vdd and gnd pins as blockages as well
# NOTE: This is done to make vdd and gnd pins DRC-safe
for pin in self.all_pins:
self.blockages.append(self.inflate_shape(pin, is_pin=True))
# Route vdd and gnd
for pin_name in [vdd_name, gnd_name]:
pins = self.pins[pin_name]
# Route closest pins according to the minimum spanning tree
for source, target in self.get_mst_pairs(list(pins)):
# This is the routing region scale
scale = 1
while True:
# Create the graph
g = graph(self)
region = g.create_graph(source, target, scale)
# Find the shortest path from source to target
path = g.find_shortest_path()
# If there is no path found, exponentially try again with a
# larger routing region
if path is None:
rll, rur = region
bll, bur = self.ring_bbox
# Stop scaling the region and throw an error
if rll.x < bll.x and rll.y < bll.y and \
rur.x > bur.x and rur.y > bur.y:
self.write_debug_gds(gds_name="{}error.gds".format(OPTS.openram_temp), g=g, source=source, target=target)
debug.error("Couldn't route from {} to {}.".format(source, target), -1)
# Exponentially scale the region
scale *= 2
debug.info(0, "Retry routing in larger routing region with scale {}".format(scale))
continue
# Create the path shapes on layout
self.add_path(path)
# Find the recently added shapes
self.prepare_gds_reader()
self.find_blockages(pin_name)
self.find_vias()
break
def prepare_gds_reader(self): def prepare_gds_reader(self):
""" Write the current layout to a temporary file to read the layout. """ """ Write the current layout to a temporary file to read the layout. """
@ -299,195 +216,6 @@ class graph_router(router_tech):
extra_spacing=self.offset) extra_spacing=self.offset)
def calculate_ring_bbox(self, num_vias=3):
""" Calculate the ring-safe bounding box of the layout. """
ll, ur = self.design.get_bbox()
# Calculate the "wideness" of a side supply pin
wideness = self.track_wire * num_vias + self.track_space * (num_vias - 1)
# Total wideness is used to find it any pin overlaps in this region. If
# so, the bbox is shifted to prevent this overlap.
total_wideness = wideness * 4
for blockage in self.blockages:
bll, bur = blockage.rect
if self.get_zindex(blockage.lpp) == 1: # Vertical
diff = ll.x + total_wideness - bll.x
if diff > 0:
ll = vector(ll.x - diff, ll.y)
diff = ur.x - total_wideness - bur.x
if diff < 0:
ur = vector(ur.x - diff, ur.y)
else: # Horizontal
diff = ll.y + total_wideness - bll.y
if diff > 0:
ll = vector(ll.x, ll.y - diff)
diff = ur.y - total_wideness - bur.y
if diff < 0:
ur = vector(ur.x, ur.y - diff)
self.ring_bbox = [ll, ur]
def add_side_pin(self, pin_name, side, num_vias=3, num_fake_pins=4):
""" Add supply pin to one side of the layout. """
ll, ur = self.ring_bbox
vertical = side in ["left", "right"]
inner = pin_name == self.gnd_name
# Calculate wires' wideness
wideness = self.track_wire * num_vias + self.track_space * (num_vias - 1)
# Calculate the offset for the inner ring
if inner:
margin = wideness * 2
else:
margin = 0
# Calculate the lower left coordinate
if side == "top":
offset = vector(ll.x + margin, ur.y - wideness - margin)
elif side == "bottom":
offset = vector(ll.x + margin, ll.y + margin)
elif side == "left":
offset = vector(ll.x + margin, ll.y + margin)
elif side == "right":
offset = vector(ur.x - wideness - margin, ll.y + margin)
# Calculate width and height
shape = ur - ll
if vertical:
shape_width = wideness
shape_height = shape.y
else:
shape_width = shape.x
shape_height = wideness
if inner:
if vertical:
shape_height -= margin * 2
else:
shape_width -= margin * 2
# Add this new pin
layer = self.get_layer(int(vertical))
pin = self.design.add_layout_pin(text=pin_name,
layer=layer,
offset=offset,
width=shape_width,
height=shape_height)
# Add fake pins on this new pin evenly
fake_pins = []
if vertical:
space = (shape_height - (2 * wideness) - num_fake_pins * self.track_wire) / (num_fake_pins + 1)
start_offset = vector(offset.x, offset.y + wideness)
else:
space = (shape_width - (2 * wideness) - num_fake_pins * self.track_wire) / (num_fake_pins + 1)
start_offset = vector(offset.x + wideness, offset.y)
for i in range(1, num_fake_pins + 1):
if vertical:
offset = vector(start_offset.x, start_offset.y + i * (space + self.track_wire))
ll = vector(offset.x, offset.y - self.track_wire)
ur = vector(offset.x + wideness, offset.y)
else:
offset = vector(start_offset.x + i * (space + self.track_wire), start_offset.y)
ll = vector(offset.x - self.track_wire, offset.y)
ur = vector(offset.x, offset.y + wideness)
rect = [ll, ur]
fake_pin = graph_shape(name=pin_name,
rect=rect,
layer_name_pp=layer)
fake_pins.append(fake_pin)
return pin, fake_pins
def add_ring_pin(self, pin_name, num_vias=3, num_fake_pins=4):
""" Add the supply ring to the layout. """
# Add side pins
new_pins = []
for side in ["top", "bottom", "right", "left"]:
new_shape, fake_pins = self.add_side_pin(pin_name, side, num_vias, num_fake_pins)
ll, ur = new_shape.rect
rect = [ll, ur]
layer = self.get_layer(side in ["left", "right"])
new_pin = graph_shape(name=pin_name,
rect=rect,
layer_name_pp=layer)
new_pins.append(new_pin)
self.pins[pin_name].update(fake_pins)
self.fake_pins.extend(fake_pins)
# Add vias to the corners
shift = self.track_wire + self.track_space
half_wide = self.track_wire / 2
for i in range(4):
ll, ur = new_pins[i].rect
if i % 2:
top_left = vector(ur.x - (num_vias - 1) * shift - half_wide, ll.y + (num_vias - 1) * shift + half_wide)
else:
top_left = vector(ll.x + half_wide, ur.y - half_wide)
for j in range(num_vias):
for k in range(num_vias):
offset = vector(top_left.x + j * shift, top_left.y - k * shift)
self.design.add_via_center(layers=self.layers,
offset=offset)
# Save side pins for routing
self.new_pins[pin_name] = new_pins
for pin in new_pins:
self.blockages.append(self.inflate_shape(pin, is_pin=True))
def get_mst_pairs(self, pins):
"""
Return the pin pairs from the minimum spanning tree in a graph that
connects all pins together.
"""
pin_count = len(pins)
# Create an adjacency matrix that connects all pins
edges = [[0] * pin_count for i in range(pin_count)]
for i in range(pin_count):
for j in range(pin_count):
# Skip if they're the same pin
if i == j:
continue
# Skip if both pins are fake
if pins[i] in self.fake_pins and pins[j] in self.fake_pins:
continue
edges[i][j] = pins[i].distance(pins[j])
pin_connected = [False] * pin_count
pin_connected[0] = True
# Add the minimum cost edge in each iteration (Prim's)
mst_pairs = []
for i in range(pin_count - 1):
min_cost = float("inf")
s = 0
t = 0
# Iterate over already connected pins
for m in range(pin_count):
# Skip if not connected
if not pin_connected[m]:
continue
# Iterate over this pin's neighbors
for n in range(pin_count):
# Skip if already connected or isn't a neighbor
if pin_connected[n] or edges[m][n] == 0:
continue
# Choose this edge if it's better the the current one
if edges[m][n] < min_cost:
min_cost = edges[m][n]
s = m
t = n
pin_connected[t] = True
mst_pairs.append((pins[s], pins[t]))
return mst_pairs
def add_path(self, path): def add_path(self, path):
""" Add the route path to the layout. """ """ Add the route path to the layout. """
@ -546,12 +274,6 @@ class graph_router(router_tech):
height=abs(diff.y) + self.track_wire) height=abs(diff.y) + self.track_wire)
def get_new_pins(self, name):
""" Return the new supply pins added by this router. """
return self.new_pins[name]
def write_debug_gds(self, gds_name="debug_route.gds", g=None, source=None, target=None): def write_debug_gds(self, gds_name="debug_route.gds", g=None, source=None, target=None):
""" Write the debug GDSII file for the router. """ """ Write the debug GDSII file for the router. """

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@ -0,0 +1,298 @@
# See LICENSE for licensing information.
#
# Copyright (c) 2016-2023 Regents of the University of California, Santa Cruz
# All rights reserved.
#
from openram import debug
from openram.base.vector import vector
from openram import OPTS
from .graph import graph
from .graph_router import graph_router
from .graph_shape import graph_shape
class supply_graph_router(graph_router):
"""
This is the supply router that uses the Hanan grid graph method.
"""
def __init__(self, layers, design, bbox=None, pin_type=None):
# `router_tech` contains tech constants for the router
graph_router.__init__(self, layers, design, bbox)
# Side supply pin type
# (can be "top", "bottom", "right", "left", and "ring")
self.pin_type = pin_type
# New pins are the side supply pins
self.new_pins = {}
def route(self, vdd_name="vdd", gnd_name="gnd"):
""" Route the given pins in the given order. """
debug.info(1, "Running router for {} and {}...".format(vdd_name, gnd_name))
# Save pin names
self.vdd_name = vdd_name
self.gnd_name = gnd_name
# Prepare gdsMill to find pins and blockages
self.prepare_gds_reader()
# Find pins to be routed
self.find_pins(vdd_name)
self.find_pins(gnd_name)
# Find blockages and vias
self.find_blockages()
self.find_vias()
# Convert blockages and vias if they overlap a pin
self.convert_vias()
self.convert_blockages()
# Add side pins
self.calculate_ring_bbox()
if self.pin_type in ["top", "bottom", "right", "left"]:
self.add_side_pin(vdd_name)
self.add_side_pin(gnd_name)
elif self.pin_type == "ring":
self.add_ring_pin(vdd_name)
self.add_ring_pin(gnd_name)
else:
debug.warning("Side supply pins aren't created.")
# Add vdd and gnd pins as blockages as well
# NOTE: This is done to make vdd and gnd pins DRC-safe
for pin in self.all_pins:
self.blockages.append(self.inflate_shape(pin, is_pin=True))
# Route vdd and gnd
for pin_name in [vdd_name, gnd_name]:
pins = self.pins[pin_name]
# Route closest pins according to the minimum spanning tree
for source, target in self.get_mst_pairs(list(pins)):
# This is the routing region scale
scale = 1
while True:
# Create the graph
g = graph(self)
region = g.create_graph(source, target, scale)
# Find the shortest path from source to target
path = g.find_shortest_path()
# If there is no path found, exponentially try again with a
# larger routing region
if path is None:
rll, rur = region
bll, bur = self.ring_bbox
# Stop scaling the region and throw an error
if rll.x < bll.x and rll.y < bll.y and \
rur.x > bur.x and rur.y > bur.y:
self.write_debug_gds(gds_name="{}error.gds".format(OPTS.openram_temp), g=g, source=source, target=target)
debug.error("Couldn't route from {} to {}.".format(source, target), -1)
# Exponentially scale the region
scale *= 2
debug.info(0, "Retry routing in larger routing region with scale {}".format(scale))
continue
# Create the path shapes on layout
self.add_path(path)
# Find the recently added shapes
self.prepare_gds_reader()
self.find_blockages(pin_name)
self.find_vias()
break
def calculate_ring_bbox(self, num_vias=3):
""" Calculate the ring-safe bounding box of the layout. """
ll, ur = self.design.get_bbox()
# Calculate the "wideness" of a side supply pin
wideness = self.track_wire * num_vias + self.track_space * (num_vias - 1)
# Total wideness is used to find it any pin overlaps in this region. If
# so, the bbox is shifted to prevent this overlap.
total_wideness = wideness * 4
for blockage in self.blockages:
bll, bur = blockage.rect
if self.get_zindex(blockage.lpp) == 1: # Vertical
diff = ll.x + total_wideness - bll.x
if diff > 0:
ll = vector(ll.x - diff, ll.y)
diff = ur.x - total_wideness - bur.x
if diff < 0:
ur = vector(ur.x - diff, ur.y)
else: # Horizontal
diff = ll.y + total_wideness - bll.y
if diff > 0:
ll = vector(ll.x, ll.y - diff)
diff = ur.y - total_wideness - bur.y
if diff < 0:
ur = vector(ur.x, ur.y - diff)
self.ring_bbox = [ll, ur]
def add_side_pin(self, pin_name, side, num_vias=3, num_fake_pins=4):
""" Add supply pin to one side of the layout. """
ll, ur = self.ring_bbox
vertical = side in ["left", "right"]
inner = pin_name == self.gnd_name
# Calculate wires' wideness
wideness = self.track_wire * num_vias + self.track_space * (num_vias - 1)
# Calculate the offset for the inner ring
if inner:
margin = wideness * 2
else:
margin = 0
# Calculate the lower left coordinate
if side == "top":
offset = vector(ll.x + margin, ur.y - wideness - margin)
elif side == "bottom":
offset = vector(ll.x + margin, ll.y + margin)
elif side == "left":
offset = vector(ll.x + margin, ll.y + margin)
elif side == "right":
offset = vector(ur.x - wideness - margin, ll.y + margin)
# Calculate width and height
shape = ur - ll
if vertical:
shape_width = wideness
shape_height = shape.y
else:
shape_width = shape.x
shape_height = wideness
if inner:
if vertical:
shape_height -= margin * 2
else:
shape_width -= margin * 2
# Add this new pin
layer = self.get_layer(int(vertical))
pin = self.design.add_layout_pin(text=pin_name,
layer=layer,
offset=offset,
width=shape_width,
height=shape_height)
# Add fake pins on this new pin evenly
fake_pins = []
if vertical:
space = (shape_height - (2 * wideness) - num_fake_pins * self.track_wire) / (num_fake_pins + 1)
start_offset = vector(offset.x, offset.y + wideness)
else:
space = (shape_width - (2 * wideness) - num_fake_pins * self.track_wire) / (num_fake_pins + 1)
start_offset = vector(offset.x + wideness, offset.y)
for i in range(1, num_fake_pins + 1):
if vertical:
offset = vector(start_offset.x, start_offset.y + i * (space + self.track_wire))
ll = vector(offset.x, offset.y - self.track_wire)
ur = vector(offset.x + wideness, offset.y)
else:
offset = vector(start_offset.x + i * (space + self.track_wire), start_offset.y)
ll = vector(offset.x - self.track_wire, offset.y)
ur = vector(offset.x, offset.y + wideness)
rect = [ll, ur]
fake_pin = graph_shape(name=pin_name,
rect=rect,
layer_name_pp=layer)
fake_pins.append(fake_pin)
return pin, fake_pins
def add_ring_pin(self, pin_name, num_vias=3, num_fake_pins=4):
""" Add the supply ring to the layout. """
# Add side pins
new_pins = []
for side in ["top", "bottom", "right", "left"]:
new_shape, fake_pins = self.add_side_pin(pin_name, side, num_vias, num_fake_pins)
ll, ur = new_shape.rect
rect = [ll, ur]
layer = self.get_layer(side in ["left", "right"])
new_pin = graph_shape(name=pin_name,
rect=rect,
layer_name_pp=layer)
new_pins.append(new_pin)
self.pins[pin_name].update(fake_pins)
self.fake_pins.extend(fake_pins)
# Add vias to the corners
shift = self.track_wire + self.track_space
half_wide = self.track_wire / 2
for i in range(4):
ll, ur = new_pins[i].rect
if i % 2:
top_left = vector(ur.x - (num_vias - 1) * shift - half_wide, ll.y + (num_vias - 1) * shift + half_wide)
else:
top_left = vector(ll.x + half_wide, ur.y - half_wide)
for j in range(num_vias):
for k in range(num_vias):
offset = vector(top_left.x + j * shift, top_left.y - k * shift)
self.design.add_via_center(layers=self.layers,
offset=offset)
# Save side pins for routing
self.new_pins[pin_name] = new_pins
for pin in new_pins:
self.blockages.append(self.inflate_shape(pin, is_pin=True))
def get_mst_pairs(self, pins):
"""
Return the pin pairs from the minimum spanning tree in a graph that
connects all pins together.
"""
pin_count = len(pins)
# Create an adjacency matrix that connects all pins
edges = [[0] * pin_count for i in range(pin_count)]
for i in range(pin_count):
for j in range(pin_count):
# Skip if they're the same pin
if i == j:
continue
# Skip if both pins are fake
if pins[i] in self.fake_pins and pins[j] in self.fake_pins:
continue
edges[i][j] = pins[i].distance(pins[j])
pin_connected = [False] * pin_count
pin_connected[0] = True
# Add the minimum cost edge in each iteration (Prim's)
mst_pairs = []
for i in range(pin_count - 1):
min_cost = float("inf")
s = 0
t = 0
# Iterate over already connected pins
for m in range(pin_count):
# Skip if not connected
if not pin_connected[m]:
continue
# Iterate over this pin's neighbors
for n in range(pin_count):
# Skip if already connected or isn't a neighbor
if pin_connected[n] or edges[m][n] == 0:
continue
# Choose this edge if it's better the the current one
if edges[m][n] < min_cost:
min_cost = edges[m][n]
s = m
t = n
pin_connected[t] = True
mst_pairs.append((pins[s], pins[t]))
return mst_pairs
def get_new_pins(self, name):
""" Return the new supply pins added by this router. """
return self.new_pins[name]