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cxp pipeline: packet handling pipeline 

tx pipeline: add CRC32 inserter
tx pipeline: add start & end of packet code inserter
tx pipeline: add packet wrapper for start & stop packet indication
tx pipeline: add code source for trigger & trigger ack packet
tx pipeline: add packet for trigger & trigger ack
tx pipeline: add test packet generator
tx pipeline: add tx_command_packet for firmware
tx command packet: add dma to store control packet
rx pipeline: add reciever path
rx pipeline: add duplicate char decoder
rx pipeline: add trig ack checker
rx pipeline: add packet decoder
decoder: add test packet checher
decoder: add packet DMA
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morgan 2024-08-29 17:39:07 +08:00
parent daaea5045d
commit 3de7f403eb
1 changed files with 527 additions and 0 deletions
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src/gateware/cxp_pipeline.py Normal file
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from migen import *
from migen.genlib.cdc import MultiReg
from misoc.interconnect.csr import *
from misoc.interconnect import stream
from functools import reduce
from itertools import combinations
from operator import or_, and_
char_width = 8
char_layout = [("data", char_width), ("k", char_width//8)]
word_dw = 32
word_layout = [("data", word_dw), ("k", word_dw//8)]
word_layout_dchar = [
("data", word_dw),
("k", word_dw//8),
("dchar", char_width),
("dchar_k", char_width//8)
]
buffer_count = 4
buffer_depth = 512
def K(x, y):
return ((y << 5) | x)
KCode = {
"pak_start" : C(K(27, 7), char_width),
"io_ack" : C(K(28, 6), char_width),
"trig_indic_28_2" : C(K(28, 2), char_width),
"stream_marker" : C(K(28, 3), char_width),
"trig_indic_28_4" : C(K(28, 4), char_width),
"pak_end" : C(K(29, 7), char_width),
"idle_comma" : C(K(28, 5), char_width),
"idle_alignment" : C(K(28, 1), char_width),
}
class Packet_Wrapper(Module):
def __init__(self):
self.sink = stream.Endpoint(word_layout)
self.source = stream.Endpoint(word_layout)
# # #
self.submodules.fsm = fsm = FSM(reset_state="IDLE")
fsm.act("IDLE",
self.sink.ack.eq(1),
If(self.sink.stb,
self.sink.ack.eq(0),
NextState("INSERT_HEADER"),
)
)
fsm.act("INSERT_HEADER",
self.sink.ack.eq(0),
self.source.stb.eq(1),
self.source.data.eq(Replicate(KCode["pak_start"], 4)),
self.source.k.eq(Replicate(1, 4)),
If(self.source.ack, NextState("COPY")),
)
fsm.act("COPY",
self.sink.connect(self.source),
self.source.eop.eq(0),
If(self.sink.stb & self.sink.eop & self.source.ack,
NextState("INSERT_FOOTER"),
),
)
fsm.act("INSERT_FOOTER",
self.sink.ack.eq(0),
self.source.stb.eq(1),
self.source.data.eq(Replicate(KCode["pak_end"], 4)),
self.source.k.eq(Replicate(1, 4)),
self.source.eop.eq(1),
If(self.source.ack, NextState("IDLE")),
)
class TX_Trigger(Module):
def __init__(self):
self.stb = Signal()
self.delay = Signal(char_width)
self.linktrig_mode = Signal()
# # #
self.sink = stream.Endpoint(char_layout)
self.source = stream.Endpoint(char_layout)
# Table 15 & 16 (CXP-001-2021)
# Send [K28.2, K28.4, K28.4] or [K28.4, K28.2, K28.2] and 3x delay as trigger packet
trig_packet = [Signal(char_width), Signal(char_width), Signal(char_width), self.delay, self.delay, self.delay]
trig_packet_k = [1, 1, 1, 0, 0, 0]
self.comb += [
If(self.linktrig_mode,
trig_packet[0].eq(KCode["trig_indic_28_4"]),
trig_packet[1].eq(KCode["trig_indic_28_2"]),
trig_packet[2].eq(KCode["trig_indic_28_2"]),
).Else(
trig_packet[0].eq(KCode["trig_indic_28_2"]),
trig_packet[1].eq(KCode["trig_indic_28_4"]),
trig_packet[2].eq(KCode["trig_indic_28_4"]),
),
]
self.submodules.fsm = fsm = FSM(reset_state="COPY")
cnt = Signal(max=6)
fsm.act("COPY",
NextValue(cnt, cnt.reset),
self.sink.connect(self.source),
If(self.stb, NextState("WRITE_TRIG"))
)
fsm.act("WRITE_TRIG",
self.sink.ack.eq(0),
self.source.stb.eq(1),
self.source.data.eq(Array(trig_packet)[cnt]),
self.source.k.eq(Array(trig_packet_k)[cnt]),
If(self.source.ack,
If(cnt == 5,
NextState("COPY"),
).Else(
NextValue(cnt, cnt + 1),
)
)
)
class Idle_Word_Inserter(Module):
def __init__(self):
self.stb = Signal()
# # #
# Section 9.2.5 (CXP-001-2021)
# Send K28.5, K28.1, K28.1, D21.5 as idle word
self.submodules.fsm = fsm = FSM(reset_state="COPY")
self.sink = stream.Endpoint(word_layout)
self.source = stream.Endpoint(word_layout)
fsm.act("COPY",
self.sink.connect(self.source),
If(self.stb, NextState("WRITE_IDLE"))
)
fsm.act("WRITE_IDLE",
self.sink.ack.eq(0),
self.source.stb.eq(1),
self.source.data.eq(Cat(KCode["idle_comma"], KCode["idle_alignment"], KCode["idle_alignment"], C(0xB5, char_width))),
self.source.k.eq(Cat(1, 1, 1, 0)),
If(self.source.ack, NextState("COPY")),
)
class Trigger_ACK_Inserter(Module):
def __init__(self):
self.stb = Signal()
# # #
# Section 9.3.2 (CXP-001-2021)
# Send 4x K28.6 and 4x 0x01 as trigger packet ack
self.submodules.fsm = fsm = FSM(reset_state="COPY")
self.sink = stream.Endpoint(word_layout)
self.source = stream.Endpoint(word_layout)
fsm.act("COPY",
self.sink.connect(self.source),
If(self.stb, NextState("WRITE_ACK0"))
)
fsm.act("WRITE_ACK0",
self.sink.ack.eq(0),
self.source.stb.eq(1),
self.source.data.eq(Replicate(KCode["io_ack"], 4)),
self.source.k.eq(Replicate(1, 4)),
If(self.source.ack, NextState("WRITE_ACK1")),
)
fsm.act("WRITE_ACK1",
self.sink.ack.eq(0),
self.source.stb.eq(1),
self.source.data.eq(Replicate(C(0x01, char_width), 4)),
self.source.k.eq(Replicate(0, 4)),
If(self.source.ack, NextState("COPY")),
)
@FullMemoryWE()
class TX_Bootstrap(Module, AutoCSR):
def __init__(self):
self.tx_word_len = CSRStorage(log2_int(buffer_depth))
self.tx = CSR()
self.tx_testseq = CSR()
self.tx_busy = CSRStatus()
# # #
self.specials.mem = mem = Memory(word_dw, buffer_depth)
self.specials.mem_port = mem_port = mem.get_port()
self.source = stream.Endpoint(word_layout)
# increment addr in the same cycle the moment addr_inc is high
# as memory takes one cycle to shift to the correct addr
addr_next = Signal(log2_int(buffer_depth))
addr = Signal.like(addr_next)
addr_rst = Signal()
addr_inc = Signal()
self.sync += addr.eq(addr_next),
self.comb += [
addr_next.eq(addr),
If(addr_rst,
addr_next.eq(addr_next.reset),
).Elif(addr_inc,
addr_next.eq(addr + 1),
),
mem_port.adr.eq(addr_next),
self.source.data.eq(mem_port.dat_r)
]
self.submodules.fsm = fsm = FSM(reset_state="IDLE")
self.sync += self.tx_busy.status.eq(~fsm.ongoing("IDLE"))
cnt = Signal(max=0xFFF)
fsm.act("IDLE",
addr_rst.eq(1),
If(self.tx.re, NextState("TRANSMIT")),
If(self.tx_testseq.re,
NextValue(cnt, cnt.reset),
NextState("WRITE_TEST_PACKET_TYPE"),
)
)
fsm.act("TRANSMIT",
self.source.stb.eq(1),
If(self.source.ack,
addr_inc.eq(1),
),
If(addr_next == self.tx_word_len.storage,
self.source.eop.eq(1),
NextState("IDLE")
)
)
fsm.act("WRITE_TEST_PACKET_TYPE",
self.source.stb.eq(1),
self.source.data.eq(Replicate(C(0x04, char_width), 4)),
self.source.k.eq(Replicate(0, 4)),
If(self.source.ack,NextState("WRITE_TEST_COUNTER"))
)
fsm.act("WRITE_TEST_COUNTER",
self.source.stb.eq(1),
self.source.data.eq(Cat(cnt[:8], cnt[:8]+1, cnt[:8]+2, cnt[:8]+3)),
self.source.k.eq(Cat(0, 0, 0, 0)),
If(self.source.ack,
If(cnt == 0xFFF-3,
self.source.eop.eq(1),
NextState("IDLE")
).Else(
NextValue(cnt, cnt + 4),
)
)
)
class RX_Debug_Buffer(Module,AutoCSR):
def __init__(self):
self.submodules.buf_out = buf_out = stream.SyncFIFO(word_layout_dchar, 128)
self.sink = buf_out.sink
self.inc = CSR()
self.dout_pak = CSRStatus(word_dw)
self.kout_pak = CSRStatus(word_dw//8)
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 Duplicated_Char_Decoder(Module):
def __init__(self):
self.sink = stream.Endpoint(word_layout)
self.source = stream.Endpoint(word_layout_dchar)
# # #
# For duplicated characters, an error correction method (e.g. majority voting) is required to meet the CXP spec:
# RX decoder should immune to single bit errors when handling duplicated characters - Section 9.2.2.1 (CXP-001-2021)
#
#
# 32
# +---> buffer -----/-----+
# 32 | | 32+8(dchar)
# sink ---/---+ ---> source -----/-----> downstream
# | 8(dchar) | decoders
# +---> majority -----/-----+
# voting
#
#
# Due to the tight setup/hold time requiremnt for 12.5Gbps CXP, the voting logic cannot be implemented as combinational logic
# Hence, a pipeline approach is needed to avoid any s/h violation, where the majority voting result are pre-calculate and injected into the bus immediate after the PHY.
# And any downstream modules can access the voting result without implementing the voting logic inside the decoder
# cycle 1 - buffer data & calculate intermediate result
buffer = stream.Endpoint(word_layout)
self.sync += [
If((~buffer.stb | buffer.ack),
buffer.stb.eq(self.sink.stb),
buffer.payload.eq(self.sink.payload),
)
]
self.comb += self.sink.ack.eq(~buffer.stb | buffer.ack)
# calculate ABC, ABD, ACD, BCD
char = [[self.sink.data[i*8:(i+1)*8], self.sink.k[i]] for i in range(4)]
voters = [Record([("data", 8), ("k", 1)]) for _ in range(4)]
for i, comb in enumerate(combinations(char, 3)):
self.sync += [
If((~buffer.stb | buffer.ack),
voters[i].data.eq(reduce(and_, [code[0] for code in comb])),
voters[i].k.eq(reduce(and_, [code[1] for code in comb])),
)
]
# cycle 2 - inject the voting result
self.sync += [
If((~self.source.stb | self.source.ack),
self.source.stb.eq(buffer.stb),
self.source.data.eq(buffer.data),
self.source.k.eq(buffer.k),
self.source.dchar.eq(Replicate(reduce(or_, [v.data for v in voters]), 4)),
self.source.dchar_k.eq(Replicate(reduce(or_, [v.k for v in voters]), 4)),
)
]
self.comb += buffer.ack.eq(~self.source.stb | self.source.ack)
@FullMemoryWE()
class RX_Bootstrap(Module):
def __init__(self):
self.packet_type = Signal(8)
self.decode_err = Signal()
self.test_err = Signal()
self.buffer_err = Signal()
# # #
# TODO: heartbeat
type = {
"data_stream": 0x01,
"control_ack_no_tag": 0x03,
"test_packet": 0x04,
"control_ack_with_tag": 0x06,
"event": 0x07,
"heartbeat": 0x09,
}
self.sink = stream.Endpoint(word_layout_dchar)
self.source = stream.Endpoint(word_layout_dchar)
self.submodules.fsm = fsm = FSM(reset_state="IDLE")
fsm.act("IDLE",
self.sink.ack.eq(1),
If((self.sink.stb & (self.sink.dchar == KCode["pak_start"]) & (self.sink.dchar_k == 1)),
NextState("DECODE"),
)
)
cnt = Signal(max=0x100)
addr_nbits = log2_int(buffer_depth)
addr = Signal(addr_nbits)
fsm.act("DECODE",
self.sink.ack.eq(1),
If(self.sink.stb,
Case(self.sink.dchar, {
type["data_stream"]: NextState("STREAMING"),
type["test_packet"]: [
NextValue(cnt, cnt.reset),
NextState("VERIFY_TEST_PATTERN"),
],
type["control_ack_no_tag"]:[
NextValue(self.packet_type, self.sink.dchar),
NextValue(addr, addr.reset),
NextState("LOAD_BUFFER"),
],
type["control_ack_with_tag"]:[
NextValue(self.packet_type, self.sink.dchar),
NextValue(addr, addr.reset),
NextState("LOAD_BUFFER"),
],
type["event"]: [
NextValue(self.packet_type, self.sink.dchar),
NextValue(addr, addr.reset),
NextState("LOAD_BUFFER"),
],
"default": [
self.decode_err.eq(1),
# wait till next valid packet
NextState("IDLE"),
],
}),
)
)
# For stream data packet
fsm.act("STREAMING",
If((self.sink.stb & (self.sink.dchar == KCode["pak_end"]) & (self.sink.dchar_k == 1)),
# discard K29,7
self.sink.ack.eq(1),
NextState("IDLE")
).Else(
self.sink.connect(self.source),
)
)
# Section 9.9.1 (CXP-001-2021)
# the received test data packet (0x00, 0x01 ... 0xFF)
# need to be compared against the local test sequence generator
fsm.act("VERIFY_TEST_PATTERN",
self.sink.ack.eq(1),
If(self.sink.stb,
If(((self.sink.dchar == KCode["pak_end"]) & (self.sink.dchar_k == 1)),
NextState("IDLE"),
).Else(
If(((self.sink.data != Cat(cnt, cnt+1, cnt+2, cnt+3))),
self.test_err.eq(1),
),
If(cnt == 0xFC,
NextValue(cnt, cnt.reset),
).Else(
NextValue(cnt, cnt + 4)
)
)
)
)
# A circular buffer for firmware to read packet from
self.specials.mem = mem = Memory(word_dw, buffer_count*buffer_depth)
self.specials.mem_port = mem_port = mem.get_port(write_capable=True)
write_ptr = Signal(log2_int(buffer_count))
self.write_ptr_sys = Signal.like(write_ptr)
self.specials += MultiReg(write_ptr, self.write_ptr_sys),
self.comb += [
mem_port.adr[:addr_nbits].eq(addr),
mem_port.adr[addr_nbits:].eq(write_ptr),
]
# For control ack, event packet
fsm.act("LOAD_BUFFER",
mem_port.we.eq(0),
self.sink.ack.eq(1),
If(self.sink.stb,
If(((self.sink.dchar == KCode["pak_end"]) & (self.sink.dchar_k == 1)),
NextState("MOVE_BUFFER_PTR"),
).Else(
mem_port.we.eq(1),
mem_port.dat_w.eq(self.sink.data),
NextValue(addr, addr + 1),
If(addr == buffer_depth - 1,
# discard the packet
self.buffer_err.eq(1),
NextState("IDLE"),
)
)
)
)
self.read_ptr_rx = Signal.like(write_ptr)
fsm.act("MOVE_BUFFER_PTR",
self.sink.ack.eq(0),
If(write_ptr + 1 == self.read_ptr_rx,
# if next one hasn't been read, overwrite the current buffer when new packet comes in
self.buffer_err.eq(1),
).Else(
NextValue(write_ptr, write_ptr + 1),
),
NextState("IDLE"),
)
class Trigger_Ack_Checker(Module, AutoCSR):
def __init__(self):
self.sink = stream.Endpoint(word_layout_dchar)
self.source = stream.Endpoint(word_layout_dchar)
self.ack = Signal()
# # #
self.submodules.fsm = fsm = FSM(reset_state="COPY")
fsm.act("COPY",
If((self.sink.stb & (self.sink.dchar == KCode["io_ack"]) & (self.sink.dchar_k == 1)),
# discard K28,6
self.sink.ack.eq(1),
NextState("CHECK_ACK")
).Else(
self.sink.connect(self.source),
)
)
fsm.act("CHECK_ACK",
If(self.sink.stb,
NextState("COPY"),
# discard the word after K28,6
self.sink.ack.eq(1),
If((self.sink.dchar == 0x01) & (self.sink.dchar_k == 0),
self.ack.eq(1),
)
)
)