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gateware/serwb: add scrambling, reduce cdc fifo depth

This commit is contained in:
Florent Kermarrec 2018-01-03 17:32:18 +01:00
parent 7f4756a869
commit 907af25a69
5 changed files with 163 additions and 33 deletions
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54
artiq/gateware/serwb/core.py
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@ -2,38 +2,54 @@ from migen import *
from misoc.interconnect import stream
from artiq.gateware.serwb.packet import Depacketizer, Packetizer
from artiq.gateware.serwb.scrambler import Scrambler, Descrambler
from artiq.gateware.serwb.packet import Packetizer, Depacketizer
from artiq.gateware.serwb.etherbone import Etherbone
class SERWBCore(Module):
def __init__(self, phy, clk_freq, mode):
def __init__(self, phy, clk_freq, mode, with_scrambling=False):
# etherbone
self.submodules.etherbone = etherbone = Etherbone(mode)
# packetizer / depacketizer
depacketizer = Depacketizer(clk_freq)
packetizer = Packetizer()
self.submodules += depacketizer, packetizer
tx_cdc = stream.AsyncFIFO([("data", 32)], 32)
tx_cdc = ClockDomainsRenamer({"write": "sys", "read": "serwb_serdes"})(tx_cdc)
self.submodules += tx_cdc
rx_cdc = stream.AsyncFIFO([("data", 32)], 32)
rx_cdc = ClockDomainsRenamer({"write": "serwb_serdes", "read": "sys"})(rx_cdc)
self.submodules += rx_cdc
# clock domain crossing
tx_cdc = stream.AsyncFIFO([("data", 32)], 16)
tx_cdc = ClockDomainsRenamer({"write": "sys", "read": phy.cd})(tx_cdc)
rx_cdc = stream.AsyncFIFO([("data", 32)], 16)
rx_cdc = ClockDomainsRenamer({"write": phy.cd, "read": "sys"})(rx_cdc)
self.submodules += tx_cdc, rx_cdc
# scrambling
scrambler = ClockDomainsRenamer(phy.cd)(Scrambler(enable=with_scrambling))
descrambler = ClockDomainsRenamer(phy.cd)(Descrambler(enable=with_scrambling))
self.submodules += scrambler, descrambler
# modules connection
self.comb += [
# core <--> etherbone
depacketizer.source.connect(etherbone.sink),
etherbone.source.connect(packetizer.sink),
# core --> serdes
# core --> phy
packetizer.source.connect(tx_cdc.sink),
tx_cdc.source.connect(scrambler.sink),
If(phy.init.ready,
If(tx_cdc.source.stb,
phy.serdes.tx_data.eq(tx_cdc.source.data)
If(scrambler.source.stb,
phy.serdes.tx_k.eq(scrambler.source.k),
phy.serdes.tx_d.eq(scrambler.source.d)
),
tx_cdc.source.ack.eq(1)
scrambler.source.ack.eq(1)
),
# serdes --> core
rx_cdc.sink.stb.eq(phy.init.ready),
rx_cdc.sink.data.eq(phy.serdes.rx_data),
# phy --> core
descrambler.sink.stb.eq(phy.init.ready),
descrambler.sink.k.eq(phy.serdes.rx_k),
descrambler.sink.d.eq(phy.serdes.rx_d),
descrambler.source.connect(rx_cdc.sink),
rx_cdc.source.connect(depacketizer.sink),
# etherbone <--> core
depacketizer.source.connect(etherbone.sink),
etherbone.source.connect(packetizer.sink)
]

21
artiq/gateware/serwb/kusphy.py
View File

@ -8,8 +8,10 @@ from misoc.cores.code_8b10b import Encoder, Decoder
class KUSSerdes(Module):
def __init__(self, pll, pads, mode="master"):
self.tx_data = Signal(32)
self.rx_data = Signal(32)
self.tx_k = Signal(4)
self.tx_d = Signal(32)
self.rx_k = Signal(4)
self.rx_d = Signal(32)
self.tx_idle = Signal()
self.tx_comma = Signal()
@ -111,10 +113,14 @@ class KUSSerdes(Module):
self.encoder.k[0].eq(1),
self.encoder.d[0].eq(0xbc)
).Else(
self.encoder.d[0].eq(self.tx_data[0:8]),
self.encoder.d[1].eq(self.tx_data[8:16]),
self.encoder.d[2].eq(self.tx_data[16:24]),
self.encoder.d[3].eq(self.tx_data[24:32])
self.encoder.k[0].eq(self.tx_k[0]),
self.encoder.k[1].eq(self.tx_k[1]),
self.encoder.k[2].eq(self.tx_k[2]),
self.encoder.k[3].eq(self.tx_k[3]),
self.encoder.d[0].eq(self.tx_d[0:8]),
self.encoder.d[1].eq(self.tx_d[8:16]),
self.encoder.d[2].eq(self.tx_d[16:24]),
self.encoder.d[3].eq(self.tx_d[24:32])
)
]
self.sync.serwb_serdes += \
@ -217,7 +223,8 @@ class KUSSerdes(Module):
self.decoders[1].input.eq(self.rx_bitslip.o[10:20]),
self.decoders[2].input.eq(self.rx_bitslip.o[20:30]),
self.decoders[3].input.eq(self.rx_bitslip.o[30:40]),
self.rx_data.eq(Cat(*[self.decoders[i].d for i in range(4)])),
self.rx_k.eq(Cat(*[self.decoders[i].k for i in range(4)])),
self.rx_d.eq(Cat(*[self.decoders[i].d for i in range(4)])),
rx_idle.eq(self.rx_bitslip.o == 0),
rx_comma.eq(((self.decoders[0].d == 0xbc) & (self.decoders[0].k == 1)) &
((self.decoders[1].d == 0x00) & (self.decoders[1].k == 0)) &

1
artiq/gateware/serwb/phy.py
View File

@ -376,6 +376,7 @@ class SERWBPLL(Module):
class SERWBPHY(Module, AutoCSR):
cd = "serwb_serdes"
def __init__(self, device, pll, pads, mode="master"):
assert mode in ["master", "slave"]
if device[:4] == "xcku":

21
artiq/gateware/serwb/s7phy.py
View File

@ -8,8 +8,10 @@ from misoc.cores.code_8b10b import Encoder, Decoder
class S7Serdes(Module):
def __init__(self, pll, pads, mode="master"):
self.tx_data = Signal(32)
self.rx_data = Signal(32)
self.tx_k = Signal(4)
self.tx_d = Signal(32)
self.rx_k = Signal(4)
self.rx_d = Signal(32)
self.tx_idle = Signal()
self.tx_comma = Signal()
@ -99,10 +101,14 @@ class S7Serdes(Module):
self.encoder.k[0].eq(1),
self.encoder.d[0].eq(0xbc)
).Else(
self.encoder.d[0].eq(self.tx_data[0:8]),
self.encoder.d[1].eq(self.tx_data[8:16]),
self.encoder.d[2].eq(self.tx_data[16:24]),
self.encoder.d[3].eq(self.tx_data[24:32])
self.encoder.k[0].eq(self.tx_k[0]),
self.encoder.k[1].eq(self.tx_k[1]),
self.encoder.k[2].eq(self.tx_k[2]),
self.encoder.k[3].eq(self.tx_k[3]),
self.encoder.d[0].eq(self.tx_d[0:8]),
self.encoder.d[1].eq(self.tx_d[8:16]),
self.encoder.d[2].eq(self.tx_d[16:24]),
self.encoder.d[3].eq(self.tx_d[24:32])
)
]
self.sync.serwb_serdes += \
@ -213,7 +219,8 @@ class S7Serdes(Module):
self.decoders[1].input.eq(self.rx_bitslip.o[10:20]),
self.decoders[2].input.eq(self.rx_bitslip.o[20:30]),
self.decoders[3].input.eq(self.rx_bitslip.o[30:40]),
self.rx_data.eq(Cat(*[self.decoders[i].d for i in range(4)])),
self.rx_k.eq(Cat(*[self.decoders[i].k for i in range(4)])),
self.rx_d.eq(Cat(*[self.decoders[i].d for i in range(4)])),
rx_idle.eq(self.rx_bitslip.o == 0),
rx_comma.eq(((self.decoders[0].d == 0xbc) & (self.decoders[0].k == 1)) &
((self.decoders[1].d == 0x00) & (self.decoders[1].k == 0)) &

99
artiq/gateware/serwb/scrambler.py Normal file
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@ -0,0 +1,99 @@
from functools import reduce
from operator import xor
from migen import *
from misoc.interconnect import stream
def K(x, y):
return (y << 5) | x
@ResetInserter()
class _Scrambler(Module):
def __init__(self, n_io, n_state=23, taps=[17, 22]):
self.i = Signal(n_io)
self.o = Signal(n_io)
# # #
state = Signal(n_state, reset=1)
curval = [state[i] for i in range(n_state)]
for i in reversed(range(n_io)):
flip = reduce(xor, [curval[tap] for tap in taps])
self.comb += self.o[i].eq(flip ^ self.i[i])
curval.insert(0, flip)
curval.pop()
self.sync += state.eq(Cat(*curval[:n_state]))
class Scrambler(Module):
def __init__(self, sync_interval=1024, enable=True):
self.sink = sink = stream.Endpoint([("data", 32)])
self.source = source = stream.Endpoint([("d", 32), ("k", 4)])
# # #
if enable:
# scrambler
scrambler = _Scrambler(32)
self.submodules += scrambler
self.comb += scrambler.i.eq(sink.data)
# insert K.29.7 as sync character
# every sync_interval cycles
count = Signal(max=sync_interval)
self.sync += count.eq(count + 1)
self.comb += [
If(count == 0,
scrambler.reset.eq(1),
source.stb.eq(1),
source.k[0].eq(1),
source.d[:8].eq(K(29, 7))
).Else(
sink.ack.eq(source.ack),
source.stb.eq(sink.stb),
source.d.eq(scrambler.o)
)
]
else:
self.comb += [
sink.connect(source, omit={"data"}),
source.k.eq(0b0000),
source.d.eq(sink.data)
]
class Descrambler(Module):
def __init__(self, enable=True):
self.sink = sink = stream.Endpoint([("d", 32), ("k", 4)])
self.source = source = stream.Endpoint([("data", 32)])
# # #
if enable:
# descrambler
descrambler = _Scrambler(32)
self.submodules += descrambler
self.comb += descrambler.i.eq(sink.d)
# detect K29.7 and synchronize descrambler
self.comb += [
descrambler.reset.eq(0),
If((sink.k[0] == 1) &
(sink.d[:8] == K(29,7)),
sink.ack.eq(1),
descrambler.reset.eq(1)
).Else(
sink.ack.eq(source.ack),
source.stb.eq(sink.stb),
source.data.eq(descrambler.o)
)
]
else:
self.comb += [
sink.connect(source, omit={"d", "k"}),
source.data.eq(sink.d)
]