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cxp downconn: add manual alignment & rxrestart

This commit is contained in:
morgan 2024-08-02 12:33:27 +08:00
parent 452c3cee64
commit bf1fd2d79b
1 changed files with 106 additions and 17 deletions
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123
src/gateware/cxp_downconn.py
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@ -13,7 +13,7 @@ from functools import reduce
class CXP_DownConn(Module, AutoCSR):
def __init__(self, refclk, pads, sys_clk_freq, debug_sma, pmod_pads):
self.rx_start_init = CSRStorage()
self.rx_restart = CSRStorage()
self.rx_restart = CSR()
self.tx_start_init = CSRStorage()
self.tx_restart = CSR()
@ -54,7 +54,7 @@ class CXP_DownConn(Module, AutoCSR):
gtx.txenable.eq(self.txenable.storage[0]),
gtx.tx_restart.eq(self.tx_restart.re),
gtx.rx_restart.eq(self.rx_restart.storage),
gtx.rx_restart.eq(self.rx_restart.re),
gtx.tx_init.clk_path_ready.eq(self.tx_start_init.storage),
gtx.rx_init.clk_path_ready.eq(self.rx_start_init.storage),
# gtx.rx_alignment_en.eq(self.rx_data_alignment.storage),
@ -100,10 +100,10 @@ class CXP_DownConn(Module, AutoCSR):
Instance("OBUF", i_I=gtx.cd_cxp_gtx_tx.clk, o_O=debug_sma.n_rx),
# pmod 0-7 pin
Instance("OBUF", i_I=gtx.tx_init.gtXxreset, o_O=pmod_pads[0]),
Instance("OBUF", i_I=gtx.tx_init.Xxdlysreset, o_O=pmod_pads[1]),
Instance("OBUF", i_I=gtx.tx_init.Xxdlysresetdone , o_O=pmod_pads[2]),
Instance("OBUF", i_I=gtx.tx_init.Xxphaligndone , o_O=pmod_pads[3]),
Instance("OBUF", i_I=gtx.clk_aligner.rxslide, o_O=pmod_pads[0]),
Instance("OBUF", i_I=gtx.clk_aligner.ready, o_O=pmod_pads[1]),
# Instance("OBUF", i_I=gtx.tx_init.Xxdlysresetdone , o_O=pmod_pads[2]),
# Instance("OBUF", i_I=gtx.tx_init.Xxphaligndone , o_O=pmod_pads[3]),
# Instance("OBUF", i_I=, o_O=pmod_pads[4]),
# Instance("OBUF", i_I=, o_O=pmod_pads[5]),
# Instance("OBUF", i_I=, o_O=pmod_pads[6]),
@ -359,7 +359,76 @@ class CXP_BruteforceClockAligner(Module):
)
)
# Warning: Xilinx transceivers are LSB first, and comma needs to be flipped
# compared to the usual 8b10b binary representation.
class Manual_Aligner(Module):
def __init__(self, comma, check_cycles=20000):
self.rxslide = Signal()
self.rxdata = Signal(20)
self.ready = Signal()
# # #
checks_reset = Signal()
error_seen = Signal()
comma_seen = Signal()
rx1cnt = Signal(max=11)
comma_n = ~comma & 0b1111111111
self.sync.cxp_gtx_rx += [
rx1cnt.eq(reduce(add, [self.rxdata[i] for i in range(10)])),
If(checks_reset,
error_seen.eq(0)
).Elif((rx1cnt != 4) & (rx1cnt != 5) & (rx1cnt != 6),
error_seen.eq(1)
),
If(checks_reset,
comma_seen.eq(0)
).Elif((self.rxdata[:10] == comma) | (self.rxdata[:10] == comma_n),
comma_seen.eq(1)
)
]
# minimum of 32 RXUSRCLK2 cycles are required between two RXSLIDE pulses
slide_timer = ClockDomainsRenamer("cxp_gtx_rx")(WaitTimer(64))
self.submodules += slide_timer
counter = Signal(reset=check_cycles-1, max=check_cycles)
fsm = ClockDomainsRenamer("cxp_gtx_rx")(FSM(reset_state="IDLE"))
self.submodules += fsm
fsm.act("IDLE",
slide_timer.wait.eq(1),
If(slide_timer.done,
If(comma_seen,
NextState("READY"),
).Else(
NextState("SLIDING")
)
)
)
fsm.act("SLIDING",
self.rxslide.eq(1),
checks_reset.eq(1),
NextState("IDLE")
)
fsm.act("READY",
self.ready.eq(1),
If(counter == 0,
NextValue(counter, check_cycles - 1),
If(error_seen,
NextState("IDLE"),
)
).Else(
NextValue(counter, counter - 1),
)
)
class GTX(Module):
# Settings:
@ -399,10 +468,12 @@ class GTX(Module):
# # #
# TX generates cxp_tx clock, init must be in system domain
# DEBUG: 500e6 is used to fix tx reset by holding gtxtxreset for a couple cycle more
# FIXME: 500e6 is used to fix Xx reset by holding gtxXxreset for a couple cycle more
self.submodules.tx_init = tx_init = GTXInit(500e6, False, mode=tx_mode)
self.submodules.rx_init = rx_init = GTXInit(500e6, True, mode=rx_mode)
# RX receives restart commands from txusrclk domain
self.submodules.rx_init = rx_init = ClockDomainsRenamer("cxp_gtx_tx")(GTXInit(qpll.tx_usrclk_freq, True, mode=rx_mode))
# self.submodules.rx_init = rx_init = ClockDomainsRenamer("cxp_gtx_tx")(GTXInit(500e6, True, mode=rx_mode))
self.comb += [
tx_init.cplllock.eq(qpll.lock),
@ -411,6 +482,8 @@ class GTX(Module):
txdata = Signal(20)
rxdata = Signal(20)
rxslide = Signal()
# Note: the following parameters were set after consulting AR45360
self.specials += \
Instance("GTXE2_CHANNEL",
@ -540,16 +613,22 @@ class GTX(Module):
# RX Byte and Word Alignment Attributes
p_ALIGN_COMMA_DOUBLE="FALSE",
p_ALIGN_COMMA_ENABLE=0b1111111111,
p_ALIGN_COMMA_WORD=1,
p_ALIGN_MCOMMA_DET="TRUE",
p_ALIGN_COMMA_WORD=2,
p_ALIGN_MCOMMA_DET="FALSE",
p_ALIGN_MCOMMA_VALUE=0b1010000011,
p_ALIGN_PCOMMA_DET="TRUE",
p_ALIGN_PCOMMA_DET="FALSE",
p_ALIGN_PCOMMA_VALUE=0b0101111100,
p_SHOW_REALIGN_COMMA="FALSE",
p_RXSLIDE_AUTO_WAIT=7,
p_RXSLIDE_MODE="PCS",
p_RX_SIG_VALID_DLY=10,
# Manual Word Alignment
i_RXPCOMMAALIGNEN=0,
i_RXMCOMMAALIGNEN=0,
i_RXCOMMADETEN=1, # enable word alignment, but breaks rxrestart if gtxXxreset hold too short
i_RXSLIDE=rxslide,
# RX 8B/10B Decoder Attributes
p_RX_DISPERR_SEQ_MATCH="FALSE",
p_DEC_MCOMMA_DETECT="TRUE",
@ -678,11 +757,21 @@ class GTX(Module):
# 125MHz: align <1s
# 156.25MHz: align <15s
# 250MHz: cannot align
clock_aligner = CXP_BruteforceClockAligner(0b0101111100, 800_000)
self.submodules += clock_aligner
# clock_aligner = CXP_BruteforceClockAligner(0b0101111100, 1_000_000)
# self.submodules += clock_aligner
# self.comb += [
# clock_aligner.rxdata.eq(rxdata),
# rx_init.restart.eq(clock_aligner.restart),
# self.rx_ready.eq(clock_aligner.ready),
# ]
self.submodules.clk_aligner = clk_aligner = Manual_Aligner(0b0101111100)
self.comb += [
clock_aligner.rxdata.eq(rxdata),
rx_init.restart.eq(clock_aligner.restart),
self.rx_ready.eq(clock_aligner.ready),
tx_init.restart.eq(self.tx_restart)
clk_aligner.rxdata.eq(rxdata),
rxslide.eq(clk_aligner.rxslide),
self.rx_ready.eq(clk_aligner.ready),
rx_init.restart.eq(self.rx_restart),
tx_init.restart.eq(self.tx_restart),
]