litex/lib/sata/link/cont.py

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from lib.sata.common import *
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from lib.sata.link.scrambler import Scrambler
from migen.genlib.misc import optree
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class SATACONTInserter(Module):
def __init__(self, description, disable=False):
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self.sink = sink = Sink(description)
self.source = source = Source(description)
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###
if disable:
self.comb += Record.connect(self.sink, self.source)
else:
self.counter = counter = Counter(max=4)
is_data = Signal()
was_data = Signal()
change = Signal()
self.comb += is_data.eq(sink.charisk == 0)
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last_data = Signal(32)
last_primitive = Signal(32)
last_charisk = Signal(4)
self.sync += [
If(sink.stb & source.ack,
last_data.eq(sink.data),
last_charisk.eq(sink.charisk),
If(~is_data,
last_primitive.eq(sink.data),
),
was_data.eq(is_data)
)
]
was_hold = last_primitive == primitives["HOLD"]
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self.comb += change.eq(
(sink.data != last_data) |
(sink.charisk != last_charisk) |
is_data
)
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# scrambler
self.scrambler = scrambler = InsertReset(Scrambler())
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# Datapath
self.comb += [
Record.connect(sink, source),
If(sink.stb,
If(~change,
counter.ce.eq(sink.ack & (counter.value !=2)),
# insert CONT
If(counter.value == 1,
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source.charisk.eq(0b0001),
source.data.eq(primitives["CONT"])
# insert scrambled data for EMI
).Elif(counter.value == 2,
scrambler.ce.eq(sink.ack),
source.charisk.eq(0b0000),
source.data.eq(scrambler.value)
)
).Else(
counter.reset.eq(source.ack),
If(counter.value == 2,
# Reinsert last primitive
If(is_data | (~is_data & was_hold),
source.stb.eq(1),
sink.ack.eq(0),
source.charisk.eq(0b0001),
source.data.eq(last_primitive)
)
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)
)
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)
]
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class SATACONTRemover(Module):
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def __init__(self, description):
self.sink = sink = Sink(description)
self.source = source = Source(description)
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###
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is_data = Signal()
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is_cont = Signal()
in_cont = Signal()
cont_ongoing = Signal()
self.comb += [
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is_data.eq(sink.charisk == 0),
is_cont.eq(~is_data & (sink.data == primitives["CONT"]))
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]
self.sync += \
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If(sink.stb & sink.ack,
If(is_cont,
in_cont.eq(1)
).Elif(~is_data,
in_cont.eq(0)
)
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)
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self.comb += cont_ongoing.eq(is_cont | (in_cont & is_data))
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# Datapath
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last_primitive = Signal(32)
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self.sync += [
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If(sink.stb & sink.ack,
If(~is_data & ~is_cont,
last_primitive.eq(sink.data)
)
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)
]
self.comb += [
Record.connect(sink, source),
If(cont_ongoing,
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source.charisk.eq(0b0001),
source.data.eq(last_primitive)
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)
]