OpenRAM/compiler/modules/capped_replica_bitcell_arra...

622 lines
29 KiB
Python

# See LICENSE for licensing information.
#
# Copyright (c) 2016-2024 Regents of the University of California, Santa Cruz
# All rights reserved.
#
from openram import debug
from openram.base import vector
from openram.base import contact
from openram.sram_factory import factory
from openram.tech import drc, spice
from openram.tech import cell_properties as props
from openram.tech import connect_ring_bottom, connect_ring_left, connect_ring_right, connect_ring_top
from openram.tech import power_ring_top, power_ring_bottom, power_ring_left, power_ring_right
from openram import OPTS
from .bitcell_base_array import bitcell_base_array
class capped_replica_bitcell_array(bitcell_base_array):
"""
Creates a replica bitcell array then adds the row and column caps to all
sides of a bitcell array.
"""
def __init__(self, rows, cols, rbl=None, left_rbl=None, right_rbl=None, name=""):
super().__init__(name, rows, cols, column_offset=0, row_offset=0)
debug.info(1, "Creating {0} {1} x {2} rbls: {3} left_rbl: {4} right_rbl: {5}".format(self.name,
rows,
cols,
rbl,
left_rbl,
right_rbl))
self.add_comment("rows: {0} cols: {1}".format(rows, cols))
self.add_comment("rbl: {0} left_rbl: {1} right_rbl: {2}".format(rbl, left_rbl, right_rbl))
self.column_size = cols
self.row_size = rows
# This is how many RBLs are in all the arrays
if rbl is not None:
self.rbl = rbl
else:
self.rbl = [0] * len(self.all_ports)
# This specifies which RBL to put on the left or right by port number
# This could be an empty list
if left_rbl is not None:
self.left_rbl = left_rbl
else:
self.left_rbl = []
# This could be an empty list
if right_rbl is not None:
self.right_rbl = right_rbl
else:
self.right_rbl=[]
self.rbls = self.left_rbl + self.right_rbl
# Two dummy rows plus replica even if we don't add the column
self.extra_rows = sum(self.rbl) + 2
# If we aren't using row/col caps, then we need to use the bitcell
#if not self.cell.end_caps:
# self.extra_rows += 2
self.create_netlist()
if not OPTS.netlist_only:
self.create_layout()
def create_netlist(self):
""" Create and connect the netlist """
self.add_modules()
self.add_pins()
self.create_instances()
def add_modules(self):
""" Array and cap rows/columns """
self.replica_bitcell_array = factory.create(module_type="replica_bitcell_array",
cols=self.column_size,
rows=self.row_size,
rbl=self.rbl,
column_offset=1,
row_offset=1,
left_rbl=self.left_rbl,
right_rbl=self.right_rbl)
# Dummy Row or Col Cap, depending on bitcell array properties
col_cap_module_type = ("col_cap_array" if self.cell.end_caps else "dummy_array")
# TODO: remove redundancy from arguments in pairs below (top/bottom, left/right)
# for example, cols takes the same value for top/bottom
self.col_cap_top = factory.create(module_type=col_cap_module_type,
cols=self.column_size + len(self.rbls),
rows=1,
# dummy column + left replica column(s)
column_offset=1,
row_offset=self.row_size+ self.extra_rows + 1, #add 1 to account for bottom col_cap
mirror=0,
location="top",
left_rbl=self.left_rbl,
right_rbl=self.right_rbl)
self.col_cap_bottom = factory.create(module_type=col_cap_module_type,
cols=self.column_size + len(self.rbls),
rows=1,
# dummy column + left replica column(s)
column_offset=1,
row_offset=0,
mirror=(1+self.row_size+self.extra_rows) % 2,
location="bottom",
left_rbl=self.left_rbl,
right_rbl=self.right_rbl)
# Dummy Col or Row Cap, depending on bitcell array properties
row_cap_module_type = ("row_cap_array" if self.cell.end_caps else "dummy_array")
self.row_cap_left = factory.create(module_type=row_cap_module_type,
cols=1,
rows=self.row_size + self.extra_rows,
column_offset=0,
row_offset=0,
location="left")
self.row_cap_right = factory.create(module_type=row_cap_module_type,
cols=1,
rows=self.row_size + self.extra_rows,
column_offset=1 + len(self.left_rbl) + self.column_size + len(self.right_rbl),
row_offset=0,
location="right")
def add_pins(self):
# Arrays are always:
# bitlines (column first then port order)
# word lines (row first then port order)
# dummy wordlines
# replica wordlines
# regular wordlines (bottom to top)
# # dummy bitlines
# replica bitlines (port order)
# regular bitlines (left to right port order)
#
# vdd
# gnd
self.add_bitline_pins()
self.add_wordline_pins()
self.add_pin("vdd", "POWER")
self.add_pin("gnd", "GROUND")
def add_bitline_pins(self):
# these four are only included for compatibility with other modules
self.bitline_names = self.replica_bitcell_array.bitline_names
self.all_bitline_names = self.replica_bitcell_array.all_bitline_names
self.rbl_bitline_names = self.replica_bitcell_array.rbl_bitline_names
self.all_rbl_bitline_names = self.replica_bitcell_array.all_rbl_bitline_names
# this one is actually used (obviously)
self.bitline_pin_list = self.replica_bitcell_array.bitline_pin_list
self.add_pin_list(self.bitline_pin_list, "INOUT")
def add_wordline_pins(self):
# some of these are just included for compatibility with modules instantiating this module
self.rbl_wordline_names = self.replica_bitcell_array.rbl_wordline_names
self.all_rbl_wordline_names = self.replica_bitcell_array.all_rbl_wordline_names
self.wordline_names = self.replica_bitcell_array.wordline_names
self.all_wordline_names = self.replica_bitcell_array.all_wordline_names
self.used_wordline_names = self.replica_bitcell_array.used_wordline_names
self.unused_wordline_names = self.replica_bitcell_array.unused_wordline_names
self.replica_array_wordline_names_with_grounded_wls = ["gnd" if x in self.unused_wordline_names else x for x in self.replica_bitcell_array.wordline_pin_list]
# Left/right row caps cover the full array height. Pad with gnd so the
# netlist list length matches the row cap (replica in the center); do
# not use col cap wordline heuristics.
n_rowcap_wl = len(self.row_cap_left.get_wordline_names())
n_rba_wl = len(self.replica_array_wordline_names_with_grounded_wls)
self.wordline_pin_list = []
if self.rbls:
self.wordline_pin_list.extend(["gnd"] * len(self.rbls))
self.wordline_pin_list.extend(self.replica_array_wordline_names_with_grounded_wls)
if self.rbls:
self.wordline_pin_list.extend(["gnd"] * len(self.rbls))
self.add_pin_list(self.used_wordline_names, "INPUT")
def create_instances(self):
""" Create the module instances used in this design """
self.supplies = ["vdd", "gnd"]
# Main array
self.replica_bitcell_array_inst=self.add_inst(name="replica_bitcell_array",
mod=self.replica_bitcell_array)
self.connect_inst(self.bitline_pin_list + self.replica_array_wordline_names_with_grounded_wls + self.supplies)
# Top/bottom dummy rows or col caps
self.dummy_row_insts = []
self.dummy_row_insts.append(self.add_inst(name="dummy_row_bot",
mod=self.col_cap_bottom,))
self.connect_inst(self.bitline_pin_list + ["gnd"] * len(self.col_cap_bottom.get_wordline_names()) + self.supplies)
self.dummy_row_insts.append(self.add_inst(name="dummy_row_top",
mod=self.col_cap_top))
self.connect_inst(self.bitline_pin_list + ["gnd"] * len(self.col_cap_top.get_wordline_names()) + self.supplies)
# Left/right Dummy columns
self.dummy_col_insts = []
self.dummy_col_insts.append(self.add_inst(name="dummy_col_left",
mod=self.row_cap_left))
self.connect_inst(["dummy_left_" + bl for bl in self.row_cap_left.all_bitline_names] + self.wordline_pin_list + self.supplies)
#print(self.dummy_col_insts[0].mod.pins)
#print(["dummy_left_" + bl for bl in self.row_cap_left.all_bitline_names] + self.wordline_pin_list + self.supplies)
self.dummy_col_insts.append(self.add_inst(name="dummy_col_right",
mod=self.row_cap_right))
self.connect_inst(["dummy_right_" + bl for bl in self.row_cap_right.all_bitline_names] + self.wordline_pin_list + self.supplies)
# bitcell array needed for some offset calculations
self.bitcell_array_inst = self.replica_bitcell_array.bitcell_array_inst
def create_layout(self):
# This creates space for the unused wordline connections as well as the
# row-based or column based power and ground lines.
self.vertical_pitch = 1.1 * getattr(self, "{}_pitch".format(self.supply_stack[0]))
self.horizontal_pitch = 1.1 * getattr(self, "{}_pitch".format(self.supply_stack[2]))
# Everything is computed with the replica array
self.replica_bitcell_array_inst.place(offset=0)
self.add_end_caps()
ll = vector(-1 * self.dummy_col_insts[0].width, -1 * self.dummy_row_insts[0].height)
self.translate_all(ll)
self.capped_rba_width = self.dummy_col_insts[0].width + self.dummy_row_insts[0].width + self.dummy_col_insts[1].width
self.capped_rba_height = self.dummy_col_insts[0].height
self.route_power_ring(self.supply_stack[2], self.supply_stack[0])
self.route_supplies()
self.route_unused_wordlines()
self.reset_coordinates()
self.add_layout_pins()
self.add_boundary()
self.DRC_LVS()
def route_power_ring(self, v_layer, h_layer):
self.bbox = (vector(0,0), vector(self.capped_rba_width, self.capped_rba_height))
# add_power_ring uses one shared ring width/pitch for both horizontal and
# vertical rails, so satisfy DRC requirements of both layers.
v_layer_width = drc("minwidth_{}".format(v_layer))
h_layer_width = drc("minwidth_{}".format(h_layer))
self.supply_rail_width = max(v_layer_width, h_layer_width)
v_layer_space = drc("{}_to_{}".format(v_layer, v_layer))
h_layer_space = drc("{}_to_{}".format(h_layer, h_layer))
# Pitch is centerline-to-centerline rail offset in add_power_ring.
# Prefer technology routing pitch so ring placement aligns with the
# routing/via grid, but never violate same-layer spacing.
drc_pitch = self.supply_rail_width + max(v_layer_space, h_layer_space)
tech_pitch = max(getattr(self, "{}_pitch".format(v_layer)),
getattr(self, "{}_pitch".format(h_layer)))
self.supply_rail_pitch = max(drc_pitch, tech_pitch)
self.add_power_ring(v_layer=v_layer, h_layer=h_layer, top=power_ring_top, bottom=power_ring_bottom, left=power_ring_left, right=power_ring_right)
def get_main_array_top(self):
return self.replica_bitcell_array_inst.by() + self.replica_bitcell_array.get_main_array_top()
def get_main_array_bottom(self):
return self.replica_bitcell_array_inst.by() + self.replica_bitcell_array.get_main_array_bottom()
def get_main_array_left(self):
return self.replica_bitcell_array_inst.lx() + self.replica_bitcell_array.get_main_array_left()
def get_main_array_right(self):
return self.replica_bitcell_array_inst.lx() + self.replica_bitcell_array.get_main_array_right()
#FIXME: these names need to be changed to reflect what they're actually returning
def get_replica_top(self):
return self.dummy_row_insts[1].by()
def get_replica_bottom(self):
return self.dummy_row_insts[0].uy()
def get_replica_left(self):
return self.dummy_col_insts[0].lx()
def get_replica_right(self):
return self.dummy_col_insts[1].rx()
def get_column_offsets(self):
"""
Return an array of the x offsets of all the regular bits
"""
# must add the offset of the instance
offsets = [self.replica_bitcell_array_inst.lx() + x for x in self.replica_bitcell_array.get_column_offsets()]
return offsets
def add_end_caps(self):
""" Add dummy cells or end caps around the array """
# Far top dummy row
offset = self.replica_bitcell_array_inst.ul()
self.dummy_row_insts[1].place(offset=offset)
# Far bottom dummy row
dummy_row_height = vector(0, self.dummy_row_insts[0].height)
offset = self.replica_bitcell_array_inst.ll() - dummy_row_height
self.dummy_row_insts[0].place(offset=offset)
# Far left dummy col
dummy_col_width = vector(self.dummy_col_insts[0].width, 0)
offset = self.dummy_row_insts[0].ll() - dummy_col_width
if self.dummy_col_insts[0].mod.cell.has_corners is False:
offset += vector(0, dummy_row_height.y)
self.dummy_col_insts[0].place(offset=offset)
# Far right dummy col
offset = self.dummy_row_insts[0].lr()
if self.dummy_col_insts[0].mod.cell.has_corners is False:
offset += vector(0, dummy_row_height.y)
self.dummy_col_insts[1].place(offset=offset)
def add_layout_pins(self):
for pin_name in self.used_wordline_names + self.bitline_pin_list:
pin = self.replica_bitcell_array_inst.get_pin(pin_name)
if "wl" in pin_name:
# wordlines
pin_offset = pin.ll().scale(0, 1)
pin_width = self.capped_rba_width
pin_height = pin.height()
else:
# bitlines
pin_offset = pin.ll().scale(1, 0)
pin_width = pin.width()
pin_height = self.capped_rba_height
self.add_layout_pin(text=pin_name,
layer=pin.layer,
offset=pin_offset,
width=pin_width,
height=pin_height)
def route_supplies(self):
if OPTS.bitcell == "pbitcell":
bitcell = factory.create(module_type="pbitcell")
else:
bitcell = getattr(props, "bitcell_{}port".format(OPTS.num_ports))
top = connect_ring_top
bottom = connect_ring_bottom
left = connect_ring_left
right = connect_ring_right
if 'vdd' in top:
inst = self.dummy_row_insts[1]
if 'vdd' in inst.mod.pins:
array_pins = inst.get_pins('vdd')
for array_pin in array_pins:
supply_pin = self.top_vdd_pin
self.add_path(array_pin.layer, [array_pin.center(), vector(array_pin.center()[0], supply_pin.center()[1])])
self.add_via_stack_center(from_layer = array_pin.layer,
to_layer = supply_pin.layer,
offset = vector(array_pin.center()[0], supply_pin.center()[1]),
directions=("V", "V"))
if 'gnd' in top:
inst = self.dummy_row_insts[1]
if 'gnd' in inst.mod.pins:
array_pins = inst.get_pins('gnd')
for array_pin in array_pins:
supply_pin = self.top_gnd_pin
self.add_path(array_pin.layer, [array_pin.center(), vector(array_pin.center()[0], supply_pin.center()[1])])
self.add_via_stack_center(from_layer = array_pin.layer,
to_layer = supply_pin.layer,
offset = vector(array_pin.center()[0], supply_pin.center()[1]),
directions=("V", "V"))
if 'vdd' in bottom:
inst = self.dummy_row_insts[0]
if 'vdd' in inst.mod.pins:
array_pins = inst.get_pins('vdd')
for array_pin in array_pins:
supply_pin = self.bottom_vdd_pin
self.add_path(array_pin.layer, [array_pin.center(), vector(array_pin.center()[0], supply_pin.center()[1])])
self.add_via_stack_center(from_layer = array_pin.layer,
to_layer = supply_pin.layer,
offset = vector(array_pin.center()[0], supply_pin.center()[1]),
directions=("V", "V"))
if 'gnd' in bottom:
inst = self.dummy_row_insts[0]
if 'gnd' in inst.mod.pins:
array_pins = inst.get_pins('gnd')
for array_pin in array_pins:
supply_pin = self.bottom_gnd_pin
self.add_path(array_pin.layer, [array_pin.center(), vector(array_pin.center()[0], supply_pin.center()[1])])
self.add_via_stack_center(from_layer = array_pin.layer,
to_layer = supply_pin.layer,
offset = vector(array_pin.center()[0], supply_pin.center()[1]),
directions=("V", "V"))
if 'vdd' in left:
inst = self.dummy_col_insts[0]
if 'vdd' in inst.mod.pins:
array_pins = inst.get_pins('vdd')
for array_pin in array_pins:
supply_pin = self.left_vdd_pin
self.add_path(array_pin.layer, [array_pin.center(), vector(supply_pin.center()[0], array_pin.center()[1])])
self.add_via_stack_center(from_layer = array_pin.layer,
to_layer = supply_pin.layer,
offset = vector(supply_pin.center()[0], array_pin.center()[1]),
directions=("H", "H"))
if 'gnd' in left:
inst = self.dummy_col_insts[0]
if 'gnd' in inst.mod.pins:
array_pins = inst.get_pins('gnd')
for array_pin in array_pins:
supply_pin = self.left_gnd_pin
self.add_path(array_pin.layer, [array_pin.center(), vector(supply_pin.center()[0], array_pin.center()[1])])
self.add_via_stack_center(from_layer = array_pin.layer,
to_layer = supply_pin.layer,
offset = vector(supply_pin.center()[0], array_pin.center()[1]),
directions=("H", "H"))
if 'vdd' in right:
inst = self.dummy_col_insts[1]
if 'vdd' in inst.mod.pins:
array_pins = inst.get_pins('vdd')
for array_pin in array_pins:
supply_pin = self.right_vdd_pin
self.add_path(array_pin.layer, [array_pin.center(), vector(supply_pin.center()[0], array_pin.center()[1])])
self.add_via_stack_center(from_layer = array_pin.layer,
to_layer = supply_pin.layer,
offset = vector(supply_pin.center()[0], array_pin.center()[1]),
directions=("H", "H"))
if 'gnd' in right:
inst = self.dummy_col_insts[1]
if 'gnd' in inst.mod.pins:
array_pins = inst.get_pins('gnd')
for array_pin in array_pins:
supply_pin = self.right_gnd_pin
self.add_path(array_pin.layer, [array_pin.center(), vector(supply_pin.center()[0], array_pin.center()[1])])
self.add_via_stack_center(from_layer = array_pin.layer,
to_layer = supply_pin.layer,
offset = vector(supply_pin.center()[0], array_pin.center()[1]),
directions=("H", "H"))
def route_unused_wordlines(self):
"""
Connect the unused RBL and dummy wordlines to gnd
"""
# This grounds all the dummy row word lines
for inst in self.dummy_row_insts:
for wl_name in inst.mod.get_wordline_names():
pin = inst.get_pin(wl_name)
self.connect_side_pin(pin, "left", self.left_gnd_pin.cx())
self.connect_side_pin(pin, "right", self.right_gnd_pin.cx())
# Ground the unused replica wordlines
for wl_name in self.unused_wordline_names:
pin = self.replica_bitcell_array_inst.get_pin(wl_name)
self.connect_side_pin(pin, "left", self.left_gnd_pin.cx())
self.connect_side_pin(pin, "right", self.right_gnd_pin.cx())
def route_side_pin(self, name, side, offset_multiple=1):
"""
Routes a vertical or horizontal pin on the side of the bbox.
The multiple specifies how many track offsets to be away from the side assuming
(0,0) (self.width, self.height)
"""
if side in ["left", "right"]:
return self.route_vertical_side_pin(name, side, offset_multiple)
elif side in ["top", "bottom", "bot"]:
return self.route_horizontal_side_pin(name, side, offset_multiple)
else:
debug.error("Invalid side {}".format(side), -1)
def route_vertical_side_pin(self, name, side, offset_multiple=1):
"""
Routes a vertical pin on the side of the bbox.
"""
if side == "left":
bot_loc = vector(-offset_multiple * self.vertical_pitch, 0)
top_loc = vector(-offset_multiple * self.vertical_pitch, self.height)
elif side == "right":
bot_loc = vector(self.width + offset_multiple * self.vertical_pitch, 0)
top_loc = vector(self.width + offset_multiple * self.vertical_pitch, self.height)
layer = self.supply_stack[2]
top_via = contact(layer_stack=self.supply_stack,
directions=("H", "H"))
self.add_layout_pin_segment_center(text=name,
layer=layer,
start=bot_loc,
end=top_loc,
width=top_via.second_layer_width)
return (bot_loc, top_loc)
def route_horizontal_side_pin(self, name, side, offset_multiple=1):
"""
Routes a horizontal pin on the side of the bbox.
"""
if side in ["bottom", "bot"]:
left_loc = vector(0, -offset_multiple * self.horizontal_pitch)
right_loc = vector(self.width, -offset_multiple * self.horizontal_pitch)
elif side == "top":
left_loc = vector(0, self.height + offset_multiple * self.horizontal_pitch)
right_loc = vector(self.width, self.height + offset_multiple * self.horizontal_pitch)
layer = self.supply_stack[0]
side_via = contact(layer_stack=self.supply_stack,
directions=("V", "V"))
self.add_layout_pin_segment_center(text=name,
layer=layer,
start=left_loc,
end=right_loc,
width=side_via.first_layer_height)
return (left_loc, right_loc)
def connect_side_pin(self, pin, side, offset):
"""
Used to connect a pin to the a horizontal or vertical strap
offset gives the location of the strap
"""
if side in ["left", "right"]:
self.connect_vertical_side_pin(pin, offset)
elif side in ["top", "bottom", "bot"]:
self.connect_horizontal_side_pin(pin, offset)
else:
debug.error("Invalid side {}".format(side), -1)
def connect_horizontal_side_pin(self, pin, yoffset):
"""
Used to connect a pin to the top/bottom horizontal straps
"""
cell_loc = pin.center()
pin_loc = vector(cell_loc.x, yoffset)
# Place the pins a track outside of the array
self.add_via_stack_center(offset=pin_loc,
from_layer=pin.layer,
to_layer=self.supply_stack[0],
directions=("V", "V"))
# Add a path to connect to the array
self.add_path(pin.layer, [cell_loc, pin_loc])
def connect_vertical_side_pin(self, pin, xoffset):
"""
Used to connect a pin to the left/right vertical straps
"""
cell_loc = pin.center()
pin_loc = vector(xoffset, cell_loc.y)
# Place the pins a track outside of the array
self.add_via_stack_center(offset=pin_loc,
from_layer=pin.layer,
to_layer=self.supply_stack[2],
directions=("H", "H"))
# Add a path to connect to the array
self.add_path(pin.layer, [cell_loc, pin_loc])
def analytical_power(self, corner, load):
"""Power of Bitcell array and bitline in nW."""
# Dynamic Power from Bitline
bl_wire = self.gen_bl_wire()
cell_load = 2 * bl_wire.return_input_cap()
bl_swing = OPTS.rbl_delay_percentage
freq = spice["default_event_frequency"]
bitline_dynamic = self.calc_dynamic_power(corner, cell_load, freq, swing=bl_swing)
# Calculate the bitcell power which currently only includes leakage
cell_power = self.cell.analytical_power(corner, load)
# Leakage power grows with entire array and bitlines.
total_power = self.return_power(cell_power.dynamic + bitline_dynamic * self.column_size,
cell_power.leakage * self.column_size * self.row_size)
return total_power
def gen_bl_wire(self):
if OPTS.netlist_only:
height = 0
else:
height = self.height
bl_pos = 0
bl_wire = self.generate_rc_net(int(self.row_size - bl_pos), height, drc("minwidth_m1"))
bl_wire.wire_c =spice["min_tx_drain_c"] + bl_wire.wire_c # 1 access tx d/s per cell
return bl_wire
def graph_exclude_bits(self, targ_row=None, targ_col=None):
"""
Excludes bits in column from being added to graph except target
"""
self.replica_bitcell_array.graph_exclude_bits(targ_row, targ_col)
def graph_exclude_replica_col_bits(self):
"""
Exclude all replica/dummy cells in the replica columns except the replica bit.
"""
self.replica_bitcell_array.graph_exclude_replica_col_bits()
def get_cell_name(self, inst_name, row, col):
"""
Gets the spice name of the target bitcell.
"""
return self.replica_bitcell_array.get_cell_name(inst_name + "{}x".format(OPTS.hier_seperator) + self.replica_bitcell_array_inst.name, row, col)
def clear_exclude_bits(self):
"""
Clears the bit exclusions
"""
self.replica_bitcell_array.clear_exclude_bits()