litex/misoc/interconnect/lasmi_bus.py

209 lines
9.0 KiB
Python

from functools import reduce
from operator import or_
from migen import *
from migen.genlib import roundrobin
from migen.genlib.record import *
class Interface(Record):
def __init__(self, aw, dw, nbanks, req_queue_size, read_latency, write_latency):
self.aw = aw
self.dw = dw
self.nbanks = nbanks
self.req_queue_size = req_queue_size
self.read_latency = read_latency
self.write_latency = write_latency
bank_layout = [
("adr", aw, DIR_M_TO_S),
("we", 1, DIR_M_TO_S),
("stb", 1, DIR_M_TO_S),
("req_ack", 1, DIR_S_TO_M),
("dat_w_ack", 1, DIR_S_TO_M),
("dat_r_ack", 1, DIR_S_TO_M),
("lock", 1, DIR_S_TO_M)
]
if nbanks > 1:
layout = [("bank"+str(i), bank_layout) for i in range(nbanks)]
else:
layout = bank_layout
layout += [
("dat_w", dw, DIR_M_TO_S),
("dat_we", dw//8, DIR_M_TO_S),
("dat_r", dw, DIR_S_TO_M)
]
Record.__init__(self, layout)
def _getattr_all(l, attr):
it = iter(l)
r = getattr(next(it), attr)
for e in it:
if getattr(e, attr) != r:
raise ValueError
return r
class LASMIxbar(Module):
def __init__(self, controllers, cba_shift):
self._controllers = controllers
self._cba_shift = cba_shift
self._rca_bits = _getattr_all(controllers, "aw")
self._dw = _getattr_all(controllers, "dw")
self._nbanks = _getattr_all(controllers, "nbanks")
self._req_queue_size = _getattr_all(controllers, "req_queue_size")
self._read_latency = _getattr_all(controllers, "read_latency")
self._write_latency = _getattr_all(controllers, "write_latency")
self._bank_bits = log2_int(self._nbanks, False)
self._controller_bits = log2_int(len(self._controllers), False)
self._masters = []
def get_master(self):
if self.finalized:
raise FinalizeError
lasmi_master = Interface(self._rca_bits + self._bank_bits + self._controller_bits,
self._dw, 1, self._req_queue_size, self._read_latency, self._write_latency)
self._masters.append(lasmi_master)
return lasmi_master
def do_finalize(self):
nmasters = len(self._masters)
m_ca, m_ba, m_rca = self._split_master_addresses(self._controller_bits,
self._bank_bits, self._rca_bits, self._cba_shift)
for nc, controller in enumerate(self._controllers):
if self._controller_bits:
controller_selected = [ca == nc for ca in m_ca]
else:
controller_selected = [1]*nmasters
master_req_acks = [0]*nmasters
master_dat_w_acks = [0]*nmasters
master_dat_r_acks = [0]*nmasters
rrs = [roundrobin.RoundRobin(nmasters, roundrobin.SP_CE) for n in range(self._nbanks)]
self.submodules += rrs
for nb, rr in enumerate(rrs):
bank = getattr(controller, "bank"+str(nb))
# for each master, determine if another bank locks it
master_locked = []
for nm, master in enumerate(self._masters):
locked = 0
for other_nb, other_rr in enumerate(rrs):
if other_nb != nb:
other_bank = getattr(controller, "bank"+str(other_nb))
locked = locked | (other_bank.lock & (other_rr.grant == nm))
master_locked.append(locked)
# arbitrate
bank_selected = [cs & (ba == nb) & ~locked for cs, ba, locked in zip(controller_selected, m_ba, master_locked)]
bank_requested = [bs & master.stb for bs, master in zip(bank_selected, self._masters)]
self.comb += [
rr.request.eq(Cat(*bank_requested)),
rr.ce.eq(~bank.stb & ~bank.lock)
]
# route requests
self.comb += [
bank.adr.eq(Array(m_rca)[rr.grant]),
bank.we.eq(Array(self._masters)[rr.grant].we),
bank.stb.eq(Array(bank_requested)[rr.grant])
]
master_req_acks = [master_req_ack | ((rr.grant == nm) & bank_selected[nm] & bank.req_ack)
for nm, master_req_ack in enumerate(master_req_acks)]
master_dat_w_acks = [master_dat_w_ack | ((rr.grant == nm) & bank.dat_w_ack)
for nm, master_dat_w_ack in enumerate(master_dat_w_acks)]
master_dat_r_acks = [master_dat_r_ack | ((rr.grant == nm) & bank.dat_r_ack)
for nm, master_dat_r_ack in enumerate(master_dat_r_acks)]
for nm, master_dat_w_ack in enumerate(master_dat_w_acks):
for i in range(self._write_latency):
new_master_dat_w_ack = Signal()
self.sync += new_master_dat_w_ack.eq(master_dat_w_ack)
master_dat_w_ack = new_master_dat_w_ack
master_dat_w_acks[nm] = master_dat_w_ack
for nm, master_dat_r_ack in enumerate(master_dat_r_acks):
for i in range(self._read_latency):
new_master_dat_r_ack = Signal()
self.sync += new_master_dat_r_ack.eq(master_dat_r_ack)
master_dat_r_ack = new_master_dat_r_ack
master_dat_r_acks[nm] = master_dat_r_ack
self.comb += [master.req_ack.eq(master_req_ack) for master, master_req_ack in zip(self._masters, master_req_acks)]
self.comb += [master.dat_w_ack.eq(master_dat_w_ack) for master, master_dat_w_ack in zip(self._masters, master_dat_w_acks)]
self.comb += [master.dat_r_ack.eq(master_dat_r_ack) for master, master_dat_r_ack in zip(self._masters, master_dat_r_acks)]
# route data writes
controller_selected_wl = controller_selected
for i in range(self._write_latency):
n_controller_selected_wl = [Signal() for i in range(nmasters)]
self.sync += [n.eq(o) for n, o in zip(n_controller_selected_wl, controller_selected_wl)]
controller_selected_wl = n_controller_selected_wl
dat_w_maskselect = []
dat_we_maskselect = []
for master, selected in zip(self._masters, controller_selected_wl):
o_dat_w = Signal(self._dw)
o_dat_we = Signal(self._dw//8)
self.comb += If(selected,
o_dat_w.eq(master.dat_w),
o_dat_we.eq(master.dat_we)
)
dat_w_maskselect.append(o_dat_w)
dat_we_maskselect.append(o_dat_we)
self.comb += [
controller.dat_w.eq(reduce(or_, dat_w_maskselect)),
controller.dat_we.eq(reduce(or_, dat_we_maskselect))
]
# route data reads
if self._controller_bits:
for master in self._masters:
controller_sel = Signal(self._controller_bits)
for nc, controller in enumerate(self._controllers):
for nb in range(nbanks):
bank = getattr(controller, "bank"+str(nb))
self.comb += If(bank.stb & bank.ack, controller_sel.eq(nc))
for i in range(self._read_latency):
n_controller_sel = Signal(self._controller_bits)
self.sync += n_controller_sel.eq(controller_sel)
controller_sel = n_controller_sel
self.comb += master.dat_r.eq(Array(self._controllers)[controller_sel].dat_r)
else:
self.comb += [master.dat_r.eq(self._controllers[0].dat_r) for master in self._masters]
def _split_master_addresses(self, controller_bits, bank_bits, rca_bits, cba_shift):
m_ca = [] # controller address
m_ba = [] # bank address
m_rca = [] # row and column address
for master in self._masters:
cba = Signal(self._controller_bits + self._bank_bits)
rca = Signal(self._rca_bits)
cba_upper = cba_shift + controller_bits + bank_bits
self.comb += cba.eq(master.adr[cba_shift:cba_upper])
if cba_shift < self._rca_bits:
if cba_shift:
self.comb += rca.eq(Cat(master.adr[:cba_shift], master.adr[cba_upper:]))
else:
self.comb += rca.eq(master.adr[cba_upper:])
else:
self.comb += rca.eq(master.adr[:cba_shift])
if self._controller_bits:
ca = Signal(self._controller_bits)
ba = Signal(self._bank_bits)
self.comb += Cat(ba, ca).eq(cba)
else:
ca = None
ba = cba
m_ca.append(ca)
m_ba.append(ba)
m_rca.append(rca)
return m_ca, m_ba, m_rca