1
0
Fork 0

cxp upconn gw: add low speed serial PHY

testing: add debug fifo output b4 encoder
cxp upconn: add low speed serial
cxp upconn: add reset, tx_busy, tx_enable
cxp upconn: add clockgen module for 20.83Mbps & 41.66Mbps using counters
cxp upconn: add oserdes using CEInserter
cxp upconn: add packet scheduler with CEInserter
scheduler: send priority packet during word/char boundary
scheduler: send IDLE every 10000 words
scheduler: encode packet before sending to oserdes
This commit is contained in:
morgan 2024-06-17 13:19:37 +08:00
parent 223c32a4dc
commit 030c4c13b9
1 changed files with 381 additions and 0 deletions

381
src/gateware/cxp_upconn.py Normal file
View File

@ -0,0 +1,381 @@
from math import ceil
from migen import *
from migen.genlib.coding import PriorityEncoder
from misoc.cores.code_8b10b import SingleEncoder
from misoc.interconnect import stream
from misoc.interconnect.csr import *
IDLE_CHARS = Array([
#[char, k]
[0xBC, 1], #K28.5
[0x3C, 1], #K28.1
[0x3C, 1], #K28.1
[0xB5, 0], #D21.5
])
@ResetInserter()
class UpConn_ClockGen(Module):
def __init__(self, sys_clk_freq):
self.clk = Signal()
self.clk_10x = Signal() # 20.83MHz 48ns or 41.66MHz 24ns
self.freq2x_enable = Signal()
# # #
period = 1e9/sys_clk_freq
max_count = ceil(48/period)
counter = Signal(max=max_count, reset=max_count-1)
clk_div = Signal(max=10, reset=9)
self.sync += [
self.clk.eq(0),
self.clk_10x.eq(0),
If(counter == 0,
self.clk_10x.eq(1),
If(self.freq2x_enable,
counter.eq(int(max_count/2)-1),
).Else(
counter.eq(counter.reset),
),
).Else(
counter.eq(counter-1),
),
If(counter == 0,
If(clk_div == 0,
self.clk.eq(1),
clk_div.eq(clk_div.reset),
).Else(
clk_div.eq(clk_div-1),
)
)
]
@ResetInserter()
@CEInserter()
class SERDES_10bits(Module):
def __init__(self, pad):
self.oe = Signal()
self.d = Signal(10)
# # #
o = Signal()
tx_bitcount = Signal(max=10)
tx_reg = Signal(10)
# DEBUG:
self.o = Signal()
self.comb += self.o.eq(o)
self.specials += Instance("OBUF", i_I=o, o_O=pad),
self.sync += [
If(self.oe,
# send LSB first
o.eq(tx_reg[0]),
tx_reg.eq(Cat(tx_reg[1:], 0)),
tx_bitcount.eq(tx_bitcount + 1),
If(tx_bitcount == 9,
tx_bitcount.eq(0),
tx_reg.eq(self.d),
),
).Else(
o.eq(0),
tx_bitcount.eq(0),
)
]
@ResetInserter()
@CEInserter()
class Packets_Scheduler(Module):
def __init__(self, tx_fifos, debug_buf):
self.tx_enable = Signal()
self.oe = Signal()
# # #
self.submodules.startup_fsm = startup_fsm = FSM(reset_state="WAIT_TX_ENABLE")
self.submodules.encoder = encoder = SingleEncoder(True)
tx_charcount = Signal(max=4)
tx_wordcount = Signal(max=10000)
idling = Signal()
priorities = Signal.like(tx_fifos.pe.o)
# DEBUG:
self.idling = Signal()
self.tx_charcount = Signal(max=4)
self.comb += [
self.idling.eq(idling),
self.tx_charcount.eq(tx_charcount),
]
startup_fsm.act("WAIT_TX_ENABLE",
If(self.tx_enable,
NextValue(idling, 1),
NextValue(tx_charcount, 0),
NextValue(encoder.d, IDLE_CHARS[0][0]),
NextValue(encoder.k, IDLE_CHARS[0][1]),
NextState("START_TX"),
# DEBUG:
If(debug_buf.sink_ack,
NextValue(debug_buf.sink_stb, 1),
NextValue(debug_buf.sink_data, IDLE_CHARS[0][0]),
NextValue(debug_buf.sink_k, IDLE_CHARS[0][1]),
)
)
)
startup_fsm.act("START_TX",
self.oe.eq(1),
If((~self.tx_enable) & (tx_charcount == 3),
NextState("WAIT_TX_ENABLE")
)
)
self.sync += [
If(self.oe,
encoder.disp_in.eq(encoder.disp_out),
If((~tx_fifos.pe.n) & (tx_fifos.pe.o == 0),
# trigger packets are inserted at char boundary and don't contribute to word count
tx_fifos.source_ack[0].eq(1),
encoder.d.eq(tx_fifos.source_data[0]),
encoder.k.eq(tx_fifos.source_k[0]),
# DEBUG:
If(debug_buf.sink_ack,
debug_buf.sink_stb.eq(1),
debug_buf.sink_data.eq(tx_fifos.source_data[0]),
debug_buf.sink_k.eq(tx_fifos.source_k[0]),
)
).Else(
If(tx_charcount == 3,
tx_charcount.eq(0),
# Section 9.2.4 (CXP-001-2021)
# other priorities packets are inserted at word boundary
If((~tx_fifos.pe.n) & (tx_wordcount != 9999),
idling.eq(0),
priorities.eq(tx_fifos.pe.o),
tx_wordcount.eq(tx_wordcount + 1),
tx_fifos.source_ack[tx_fifos.pe.o].eq(1),
encoder.d.eq(tx_fifos.source_data[tx_fifos.pe.o]),
encoder.k.eq(tx_fifos.source_k[tx_fifos.pe.o]),
# DEBUG:
If(debug_buf.sink_ack,
debug_buf.sink_stb.eq(1),
debug_buf.sink_data.eq(tx_fifos.source_data[tx_fifos.pe.o]),
debug_buf.sink_k.eq(tx_fifos.source_k[tx_fifos.pe.o]),
)
).Else(
# Section 9.2.5.1 (CXP-001-2021)
# IDLE word shall be transmitted at least once every 10,000 words, but should not be inserted into trigger packet
idling.eq(1),
tx_wordcount.eq(0),
encoder.d.eq(IDLE_CHARS[0][0]),
encoder.k.eq(IDLE_CHARS[0][1]),
# DEBUG:
If(debug_buf.sink_ack,
debug_buf.sink_stb.eq(1),
debug_buf.sink_data.eq(IDLE_CHARS[0][0]),
debug_buf.sink_k.eq(IDLE_CHARS[0][1]),
)
)
).Else(
tx_charcount.eq(tx_charcount + 1),
If(~idling,
tx_fifos.source_ack[priorities].eq(1),
encoder.d.eq(tx_fifos.source_data[priorities]),
encoder.k.eq(tx_fifos.source_k[priorities]),
# DEBUG:
If(debug_buf.sink_ack,
debug_buf.sink_stb.eq(1),
debug_buf.sink_data.eq(tx_fifos.source_data[priorities]),
debug_buf.sink_k.eq(tx_fifos.source_k[priorities]),
)
).Else(
encoder.d.eq(IDLE_CHARS[tx_charcount + 1][0]),
encoder.k.eq(IDLE_CHARS[tx_charcount + 1][1]),
# DEBUG:
If(debug_buf.sink_ack,
debug_buf.sink_stb.eq(1),
debug_buf.sink_data.eq(IDLE_CHARS[tx_charcount + 1][0]),
debug_buf.sink_k.eq(IDLE_CHARS[tx_charcount + 1][1]),
)
)
),
),
)
]
class PHY_Interface(Module):
def __init__(self, layout, nsink):
self.source_stb = Signal(nsink)
self.source_ack = Array(Signal() for _ in range(nsink))
self.source_data = Array(Signal(8) for _ in range(nsink))
self.source_k = Array(Signal() for _ in range(nsink))
# # #
self.sinks = []
for i in range(nsink):
sink = stream.Endpoint(layout)
self.sinks += [sink]
self.sync += [
If(self.source_ack[i],
# reset ack after asserted
# since upconn clk run much slower, the ack will be high for longer than expected which will result in data loss
self.source_ack[i].eq(0),
sink.ack.eq(1),
).Else(
sink.ack.eq(0),
),
self.source_stb[i].eq(sink.stb),
self.source_data[i].eq(sink.data),
self.source_k[i].eq(sink.k),
]
# FIFOs transmission priority
self.submodules.pe = PriorityEncoder(nsink)
self.comb += self.pe.i.eq(self.source_stb)
class Debug_buffer(Module,AutoCSR):
def __init__(self, layout):
self.sink_stb = Signal()
self.sink_ack = Signal()
self.sink_data = Signal(8)
self.sink_k = Signal()
# # #
self.submodules.buf_out = buf_out = stream.SyncFIFO(layout, 128)
self.sync += [
If(self.sink_stb,
# reset ack after asserted
# since upconn clk run much slower, the stb will be high for longer than expected which will result in multiple data entry
self.sink_stb.eq(0),
buf_out.sink.stb.eq(1),
).Else(
buf_out.sink.stb.eq(0),
),
self.sink_ack.eq(buf_out.sink.ack),
buf_out.sink.data.eq(self.sink_data),
buf_out.sink.k.eq(self.sink_k),
]
self.inc = CSR()
self.dout_pak = CSRStatus(8)
self.kout_pak = CSRStatus()
self.dout_valid = CSRStatus()
self.sync += [
# output
buf_out.source.ack.eq(self.inc.re),
self.dout_pak.status.eq(buf_out.source.data),
self.kout_pak.status.eq(buf_out.source.k),
self.dout_valid.status.eq(buf_out.source.stb),
]
class CXP_UpConn_PHY(Module, AutoCSR):
def __init__(self, pad, sys_clk_freq, debug_sma, pmod_pads, layout, nsink=3):
self.bitrate2x_enable = Signal()
self.clk_reset = Signal()
self.tx_enable = Signal()
self.tx_busy = Signal()
# # #
self.submodules.cg = cg = UpConn_ClockGen(sys_clk_freq)
self.submodules.interface = interface = PHY_Interface(layout, nsink)
self.sinks = interface.sinks
# DEBUG:
self.submodules.debug_buf = debug_buf = Debug_buffer(layout)
self.submodules.scheduler = scheduler = Packets_Scheduler(interface, debug_buf)
self.submodules.serdes = serdes = SERDES_10bits(pad)
self.comb += [
self.tx_busy.eq(interface.source_stb != 0),
cg.reset.eq(self.clk_reset),
cg.freq2x_enable.eq(self.bitrate2x_enable),
scheduler.reset.eq(self.clk_reset),
scheduler.ce.eq(cg.clk),
scheduler.tx_enable.eq(self.tx_enable),
serdes.reset.eq(self.clk_reset),
serdes.ce.eq(cg.clk_10x),
serdes.d.eq(scheduler.encoder.output),
serdes.oe.eq(scheduler.oe),
]
# DEBUG: remove pads
prioity_0 = Signal()
word_bound = Signal()
p0 = Signal()
p3 = Signal()
self.comb += [
prioity_0.eq((~interface.pe.n) & (interface.pe.o == 0)),
word_bound.eq(scheduler.tx_charcount == 3),
# because of clk delay
p0.eq(scheduler.tx_charcount == 2),
p3.eq(scheduler.tx_charcount == 1),
]
self.specials += [
# # debug sma
# Instance("OBUF", i_I=cg.clk, o_O=debug_sma.p_tx),
# Instance("OBUF", i_I=cg.clk_10x, o_O=debug_sma.n_rx),
# # pmod 0-7 pin
# Instance("OBUF", i_I=serdes.o, o_O=pmod_pads[0]),
# Instance("OBUF", i_I=cg.clk_10x, o_O=pmod_pads[1]),
# Instance("OBUF", i_I=~tx_fifos.pe.n, o_O=pmod_pads[2]),
# Instance("OBUF", i_I=prioity_0, o_O=pmod_pads[3]),
# Instance("OBUF", i_I=word_bound, o_O=pmod_pads[4]),
# Instance("OBUF", i_I=debug_buf.buf_out.sink.stb, o_O=pmod_pads[4]),
# Instance("OBUF", i_I=debug_buf.buf_out.sink.ack, o_O=pmod_pads[5]),
# Instance("OBUF", i_I=debug_buf.buf_out.source.stb, o_O=pmod_pads[6]),
# Instance("OBUF", i_I=debug_buf.buf_out.source.ack, o_O=pmod_pads[7]),
# Instance("OBUF", i_I=scheduler.idling, o_O=pmod_pads[5]),
# # Instance("OBUF", i_I=tx_fifos.source_ack[0], o_O=pmod[6]),
# # Instance("OBUF", i_I=tx_fifos.source_ack[2], o_O=pmod[6]),
# # Instance("OBUF", i_I=tx_fifos.source_ack[1], o_O=pmod[7]),
# Instance("OBUF", i_I=p0, o_O=pmod_pads[6]),
# Instance("OBUF", i_I=p3, o_O=pmod_pads[7]),
]