litex/migen/flow/network.py

146 lines
4.3 KiB
Python

from networkx import MultiDiGraph
from migen.fhdl.structure import *
from migen.flow.actor import *
from migen.corelogic.misc import optree
# Graph nodes can be either:
# (1) a reference to an existing actor
# (2) an abstract (class, dictionary) pair meaning that the actor class should be
# instantiated with the parameters from the dictionary.
# This form is needed to enable actor duplication or sharing during elaboration.
class ActorNode:
def __init__(self, actor_class, parameters=None):
if isinstance(actor_class, type):
self.actor_class = actor_class
self.parameters = parameters
else:
self.actor = actor_class
self.name = None
def is_abstract(self):
return hasattr(self, "actor_class")
def instantiate(self):
if self.is_abstract():
self.actor = self.actor_class(**self.parameters)
del self.actor_class
del self.parameters
def get_dict(self):
if self.is_abstract():
return self.parameters
else:
return self.actor.__dict__
def __repr__(self):
if self.is_abstract():
r = "<abstract " + self.actor_class.__name__
if self.name is not None:
r += ": " + self.name
r += ">"
else:
r = repr(self.actor)
return r
class DataFlowGraph(MultiDiGraph):
def __init__(self):
self.elaborated = False
super().__init__()
def add_connection(self, source_node, sink_node,
source_ep=None, sink_ep=None, # default: assume nodes have 1 source/sink and use that one
source_subr=None, sink_subr=None): # default: use whole record
if not isinstance(source_node, ActorNode):
source_node = ActorNode(source_node)
if not isinstance(sink_node, ActorNode):
sink_node = ActorNode(sink_node)
self.add_edge(source_node, sink_node,
source=source_ep, sink=sink_ep,
source_subr=source_subr, sink_subr=sink_subr)
# Returns a dictionary
# source -> [sink1, ..., sinkn]
# each element being as a (node, endpoint) pair.
# NB: ignores subrecords.
def _source_to_sinks(self):
d = dict()
for u, v, data in self.edges_iter(data=True):
el_src = (u, data["source"])
el_dst = (v, data["sink"])
if el_src in d:
d[el_src].append(el_dst)
else:
d[el_src] = [el_dst]
return d
# List sources that feed more than one sink.
# NB: ignores subrecords.
def _list_divergences(self):
d = self._source_to_sinks()
return dict((k, v) for k, v in d.items() if len(v) > 1)
# A graph is abstract if any of these conditions is met:
# (1) A node is an abstract actor.
# (2) A subrecord is used.
# (3) A single source feeds more than one sink.
# NB: It is not allowed for a single sink to be fed by more than one source.
def is_abstract(self):
return any(x.is_abstract() for x in self) \
or any(d["source_subr"] is not None or d["sink_subr"] is not None
for u, v, d in self.edges_iter(data=True)) \
or self._list_divergences()
def _eliminate_subrecords(self):
pass # TODO
def _eliminate_divergences(self):
pass # TODO
def _instantiate_actors(self):
for actor in self:
actor.instantiate()
for u, v, d in self.edges_iter(data=True):
if d["source"] is None:
source_eps = u.actor.sources()
assert(len(source_eps) == 1)
d["source"] = source_eps[0]
if d["sink"] is None:
sink_eps = v.actor.sinks()
assert(len(sink_eps) == 1)
d["sink"] = sink_eps[0]
# Elaboration turns an abstract DFG into a concrete one.
# Pass 1: eliminate subrecords by inserting Combinator/Splitter actors
# Pass 2: eliminate divergences by inserting Distributor actors
# Pass 3: run optimizer (e.g. share and duplicate actors)
# Pass 4: instantiate all abstract actors and explicit "None" endpoints
def elaborate(self, optimizer=None):
if self.elaborated:
return
self.elaborated = True
self._eliminate_subrecords()
self._eliminate_divergences()
if optimizer is not None:
optimizer(self)
self._instantiate_actors()
class CompositeActor(Actor):
def __init__(self, dfg):
dfg.elaborate()
self.dfg = dfg
super().__init__()
def get_fragment(self):
comb = [self.busy.eq(optree("|", [node.actor.busy for node in self.dfg]))]
fragment = Fragment(comb)
for node in self.dfg:
fragment += node.actor.get_fragment()
for u, v, d in self.dfg.edges_iter(data=True):
ep_src = u.actor.endpoints[d["source"]]
ep_dst = v.actor.endpoints[d["sink"]]
fragment += get_conn_fragment(ep_src, ep_dst)
return fragment