litex/lib/sata/link/cont.py

121 lines
2.8 KiB
Python

from migen.fhdl.std import *
from migen.genlib.misc import optree
from lib.sata.std import *
from lib.sata.link.scrambler import Scrambler
class SATACONTInserter(Module):
def __init__(self, layout):
self.sink = sink = Sink(layout)
self.source = source = Source(layout)
###
# Detect consecutive primitives
# tn insert CONT
cnt = Signal(2)
is_primitive = Signal()
last_was_primitive = Signal()
last_primitive = Signal(32)
change = Signal()
cont_insert = Signal()
scrambler_insert = Signal()
last_primitive_insert = Signal()
last_primitive_insert_d = Signal()
self.comb += [
is_primitive.eq(sink.charisk != 0),
change.eq((sink.data != last_primitive) | ~is_primitive),
cont_insert.eq(~change & (cnt==1)),
scrambler_insert.eq(~change & (cnt==2)),
last_primitive_insert.eq((cnt==2) & (
(~is_primitive & last_was_primitive) |
(is_primitive & (last_primitive == primitives["HOLD"]) & (last_primitive != sink.data))))
]
self.sync += \
If(sink.stb & source.ack,
last_primitive_insert_d.eq(last_primitive_insert),
If(is_primitive,
last_primitive.eq(sink.data),
last_was_primitive.eq(1)
).Else(
last_was_primitive.eq(0)
),
If(change | last_primitive_insert_d,
cnt.eq(0)
).Else(
If(~scrambler_insert,
cnt.eq(cnt+1)
)
)
)
# scrambler (between CONT and next primitive)
scrambler = InsertReset(Scrambler())
self.submodules += scrambler
self.comb += [
scrambler.reset.eq(ResetSignal()), #XXX: should be reseted on COMINIT / COMRESET
scrambler.ce.eq(scrambler_insert & source.stb & source.ack)
]
# Datapath
self.comb += [
Record.connect(sink, source),
If(sink.stb,
If(cont_insert,
source.charisk.eq(0b0001),
source.data.eq(primitives["CONT"])
).Elif(scrambler_insert,
source.charisk.eq(0b0000),
source.data.eq(scrambler.value)
).Elif(last_primitive_insert,
source.stb.eq(1),
sink.ack.eq(0),
source.charisk.eq(0b0001),
source.data.eq(last_primitive)
)
)
]
class SATACONTRemover(Module):
def __init__(self, layout):
self.sink = sink = Sink(layout)
self.source = source = Source(layout)
###
# Detect CONT
is_primitive = Signal()
is_cont = Signal()
in_cont = Signal()
cont_ongoing = Signal()
self.comb += [
is_primitive.eq(sink.charisk != 0),
is_cont.eq(is_primitive & (sink.data == primitives["CONT"]))
]
self.sync += \
If(is_cont,
in_cont.eq(1)
).Elif(is_primitive,
in_cont.eq(0)
)
self.comb += cont_ongoing.eq(is_cont | (in_cont & ~is_primitive))
# Datapath
last_primitive = Signal()
self.sync += [
If(is_primitive & ~is_cont,
last_primitive.eq(sink.data)
)
]
self.comb += [
Record.connect(sink, source),
If(cont_ongoing,
source.charisk.eq(0b0001),
source.data.eq(last_primitive)
)
]