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from migen.fhdl.structure import *
from migen.corelogic.misc import optree
class SchedulingModel:
COMBINATORIAL, SEQUENTIAL, PIPELINE, DYNAMIC = range(4)
def __init__(self, model, latency=1):
self.model = model
self.latency = latency
def __repr__(self):
if self.model == SchedulingModel.COMBINATORIAL:
return "<SchedulingModel: COMBINATORIAL>"
elif self.model == SchedulingModel.SEQUENTIAL:
return "<SchedulingModel: SEQUENTIAL({0})>".format(self.latency)
elif self.model == SchedulingModel.PIPELINE:
return "<SchedulingModel: PIPELINE({0})>".format(self.latency)
elif self.model == SchedulingModel.DYNAMIC:
return "<SchedulingModel: DYNAMIC>"
else:
raise AttributeError
class Endpoint:
def __init__(self, token):
self.token = token
if isinstance(self, Sink):
self.stb = Signal(namer="stb_i")
self.ack = Signal(namer="ack_o")
else:
self.stb = Signal(namer="stb_o")
self.ack = Signal(namer="ack_i")
def token_signal(self):
sigs = self.token.flatten()
assert(len(sigs) == 1)
return sigs[0]
def __hash__(self):
return id(self)
def __repr__(self):
return "<Endpoint " + str(self.token) + ">"
class Sink(Endpoint):
def __repr__(self):
return "<Sink " + str(self.token) + ">"
class Source(Endpoint):
def __repr__(self):
return "<Source " + str(self.token) + ">"
def _control_fragment_comb(stb_i, ack_o, stb_o, ack_i, busy):
return Fragment([stb_o.eq(stb_i), ack_o.eq(ack_i), busy.eq(0)])
def _control_fragment_seq(latency, stb_i, ack_o, stb_o, ack_i, busy, trigger):
ready = Signal()
timer = Signal(BV(bits_for(latency)))
comb = [ready.eq(timer == 0)]
sync = [
If(trigger,
timer.eq(latency)
).Elif(~ready,
timer.eq(timer - 1)
)
]
mask = Signal()
comb += [
stb_o.eq(ready & mask),
trigger.eq(stb_i & (ack_i | ~mask) & ready),
ack_o.eq(trigger),
busy.eq(~ready)
]
sync += [
If(trigger, mask.eq(1)),
If(stb_o & ack_i, mask.eq(0))
]
return Fragment(comb, sync)
def _control_fragment_pipe(latency, stb_i, ack_o, stb_o, ack_i, busy, pipe_ce):
valid = Signal(BV(latency))
if latency > 1:
sync = [If(pipe_ce, valid.eq(Cat(stb_i, valid[:latency-1])))]
else:
sync = [If(pipe_ce, valid.eq(stb_i))]
last_valid = valid[latency-1]
comb = [
pipe_ce.eq(ack_i | ~last_valid),
ack_o.eq(pipe_ce),
stb_o.eq(last_valid),
busy.eq(optree('|', [valid[i] for i in range(latency)]))
]
return Fragment(comb, sync)
class Actor:
def __init__(self, scheduling_model, sinks=None, sources=None, endpoints=None):
self.scheduling_model = scheduling_model
if endpoints is None:
if isinstance(sinks, list):
self.endpoints = [Sink(sink) for sink in sinks]
else:
self.endpoints = [Sink(sinks)]
if isinstance(sources, list):
self.endpoints += [Source(source) for source in sources]
else:
self.endpoints.append(Source(sources))
else:
self.endpoints = endpoints
self.busy = Signal()
if self.scheduling_model.model == SchedulingModel.SEQUENTIAL:
self.trigger = Signal()
elif self.scheduling_model.model == SchedulingModel.PIPELINE:
self.pipe_ce = Signal()
def sinks(self):
return [x for x in self.endpoints if isinstance(x, Sink)]
def sources(self):
return [x for x in self.endpoints if isinstance(x, Source)]
def get_control_fragment(self):
if len(self.endpoints) != 2:
raise ValueError("Actors with automatic control fragment must have exactly two endpoints.")
if isinstance(self.endpoints[0], Sink):
assert(isinstance(self.endpoints[1], Source))
sink = self.endpoints[0]
source = self.endpoints[1]
elif isinstance(self.endpoints[0], Source):
assert(isinstance(self.endpoints[1], Sink))
sink = self.endpoints[1]
source = self.endpoints[0]
else:
raise ValueError("Actors with automatic control fragment must have one sink and one source. Consider using plumbing actors.")
stb_i = sink.stb
ack_o = sink.ack
stb_o = source.stb
ack_i = source.ack
if self.scheduling_model.model == SchedulingModel.COMBINATORIAL:
return _control_fragment_comb(stb_i, ack_o, stb_o, ack_i, self.busy)
elif self.scheduling_model.model == SchedulingModel.SEQUENTIAL:
return _control_fragment_seq(self.scheduling_model.latency, stb_i, ack_o, stb_o, ack_i, self.busy, self.trigger)
elif self.scheduling_model.model == SchedulingModel.PIPELINE:
return _control_fragment_pipe(self.scheduling_model.latency, stb_i, ack_o, stb_o, ack_i, self.busy, self.pipe_ce)
elif self.scheduling_model.model == SchedulingModel.DYNAMIC:
raise NotImplementedError("Actor classes with dynamic scheduling must overload get_control_fragment or get_fragment")
def get_process_fragment(self):
raise NotImplementedError("Actor classes must overload get_process_fragment")
def get_fragment(self):
return self.get_control_fragment() + self.get_process_fragment()
def __repr__(self):
return "<" + self.__class__.__name__ + " " + repr(self.scheduling_model) + " " + repr(self.sinks()) + " " + repr(self.sources()) + ">"
def get_conn_fragment(source, sink):
assert isinstance(source, Source)
assert isinstance(sink, Sink)
assert sink.token.compatible(source.token)
sigs_source = source.token.flatten()
sigs_sink = sink.token.flatten()
comb = [
source.ack.eq(sink.ack),
sink.stb.eq(source.stb),
Cat(*sigs_sink).eq(Cat(*sigs_source))
]
return Fragment(comb)
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