66 lines
1.5 KiB
Python
66 lines
1.5 KiB
Python
from liteeth.common import *
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def _decode_header(h_dict, h_signal, obj):
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r = []
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for k, v in sorted(h_dict.items()):
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start = v.byte*8+v.offset
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end = start+v.width
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r.append(getattr(obj, k).eq(reverse_bytes(h_signal[start:end])))
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return r
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class LiteEthDepacketizer(Module):
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def __init__(self, sink_description, source_description, header_type, header_length):
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self.sink = sink = Sink(sink_description)
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self.source = source = Source(source_description)
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###
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shift = Signal()
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header = Signal(header_length*8)
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counter = Counter(max=header_length)
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self.submodules += counter
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self.sync += \
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If(shift,
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header.eq(Cat(header[8:], sink.data))
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)
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fsm = FSM(reset_state="IDLE")
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self.submodules += fsm
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fsm.act("IDLE",
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sink.ack.eq(1),
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counter.reset.eq(1),
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If(sink.stb,
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shift.eq(1),
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NextState("RECEIVE_HEADER")
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)
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)
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fsm.act("RECEIVE_HEADER",
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sink.ack.eq(1),
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If(sink.stb,
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counter.ce.eq(1),
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shift.eq(1),
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If(counter.value == header_length-2,
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NextState("COPY")
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)
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)
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)
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self.sync += \
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If(fsm.before_entering("COPY"),
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source.sop.eq(1)
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).Elif(source.stb & source.ack,
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source.sop.eq(0)
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)
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self.comb += [
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source.eop.eq(sink.eop),
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source.data.eq(sink.data),
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source.error.eq(sink.error),
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_decode_header(header_type, header, source)
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]
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fsm.act("COPY",
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sink.ack.eq(source.ack),
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source.stb.eq(sink.stb),
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If(source.stb & source.ack & source.eop,
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NextState("IDLE")
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)
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)
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