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rtio/sed: latency compensation

This commit is contained in:
Sebastien Bourdeauducq 2017-09-26 15:09:07 +08:00
parent e430d04d3f
commit 4112e403de
3 changed files with 47 additions and 22 deletions
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4
artiq/gateware/rtio/sed/core.py
View File

@ -31,7 +31,9 @@ class SED(Module):
self.submodules.lane_dist = lane_dist_cdr(
LaneDistributor(lane_count, seqn_width,
layouts.fifo_payload(channels), glbl_fine_ts_width,
layouts.fifo_payload(channels),
[channel.interface.o.delay for channel in channels],
glbl_fine_ts_width,
enable_spread=enable_spread,
quash_channels=quash_channels,
interface=interface))

62
artiq/gateware/rtio/sed/lane_distributor.py
View File

@ -13,7 +13,8 @@ __all__ = ["LaneDistributor"]
# 3. check status
class LaneDistributor(Module):
def __init__(self, lane_count, seqn_width, layout_payload, glbl_fine_ts_width,
def __init__(self, lane_count, seqn_width, layout_payload,
compensation, glbl_fine_ts_width,
enable_spread=True, quash_channels=[], interface=None):
if lane_count & (lane_count - 1):
raise NotImplementedError("lane count must be a power of 2")
@ -53,27 +54,20 @@ class LaneDistributor(Module):
self.comb += lio.payload.data.eq(self.cri.o_data)
# when timestamp and channel arrive in cycle #1, prepare computations
coarse_timestamp = Signal(64-glbl_fine_ts_width)
us_timestamp_width = 64 - glbl_fine_ts_width
coarse_timestamp = Signal(us_timestamp_width)
self.comb += coarse_timestamp.eq(self.cri.timestamp[glbl_fine_ts_width:])
timestamp_above_min = Signal()
timestamp_above_laneA_min = Signal()
timestamp_above_laneB_min = Signal()
force_laneB = Signal()
use_laneB = Signal()
use_lanen = Signal(max=lane_count)
min_minus_timestamp = Signal((us_timestamp_width + 1, True))
laneAmin_minus_timestamp = Signal((us_timestamp_width + 1, True))
laneBmin_minus_timestamp = Signal((us_timestamp_width + 1, True))
last_minus_timestamp = Signal((us_timestamp_width + 1, True))
current_lane_plus_one = Signal(max=lane_count)
self.comb += current_lane_plus_one.eq(current_lane + 1)
self.sync += [
timestamp_above_min.eq(coarse_timestamp > self.minimum_coarse_timestamp),
timestamp_above_laneA_min.eq(coarse_timestamp > last_lane_coarse_timestamps[current_lane]),
timestamp_above_laneB_min.eq(coarse_timestamp > last_lane_coarse_timestamps[current_lane_plus_one]),
If(force_laneB | (coarse_timestamp <= last_coarse_timestamp),
use_lanen.eq(current_lane + 1),
use_laneB.eq(1)
).Else(
use_lanen.eq(current_lane),
use_laneB.eq(0)
)
min_minus_timestamp.eq(self.minimum_coarse_timestamp - coarse_timestamp),
laneAmin_minus_timestamp.eq(last_lane_coarse_timestamps[current_lane] - coarse_timestamp),
laneBmin_minus_timestamp.eq(last_lane_coarse_timestamps[current_lane_plus_one] - coarse_timestamp),
last_minus_timestamp.eq(last_coarse_timestamp - coarse_timestamp)
]
quash = Signal()
@ -81,12 +75,36 @@ class LaneDistributor(Module):
for channel in quash_channels:
self.sync += If(self.cri.chan_sel[:16] == channel, quash.eq(1))
latency_compensation = Memory(14, len(compensation), init=compensation)
latency_compensation_port = latency_compensation.get_port()
self.specials += latency_compensation, latency_compensation_port
self.comb += latency_compensation_port.adr.eq(self.cri.chan_sel[:16])
# cycle #2, write
compensation = latency_compensation_port.dat_r
timestamp_above_min = Signal()
timestamp_above_laneA_min = Signal()
timestamp_above_laneB_min = Signal()
timestamp_above_lane_min = Signal()
force_laneB = Signal()
use_laneB = Signal()
use_lanen = Signal(max=lane_count)
do_write = Signal()
do_underflow = Signal()
do_sequence_error = Signal()
self.comb += [
timestamp_above_min.eq(min_minus_timestamp - compensation < 0),
timestamp_above_laneA_min.eq(laneAmin_minus_timestamp - compensation < 0),
timestamp_above_laneB_min.eq(laneBmin_minus_timestamp - compensation < 0),
If(force_laneB | (last_minus_timestamp - compensation >= 0),
use_lanen.eq(current_lane + 1),
use_laneB.eq(1)
).Else(
use_lanen.eq(current_lane),
use_laneB.eq(0)
),
timestamp_above_lane_min.eq(Mux(use_laneB, timestamp_above_laneB_min, timestamp_above_laneA_min)),
If(~quash,
do_write.eq((self.cri.cmd == cri.commands["write"]) & timestamp_above_min & timestamp_above_lane_min),
@ -95,14 +113,18 @@ class LaneDistributor(Module):
),
Array(lio.we for lio in self.output)[use_lanen].eq(do_write)
]
compensated_timestamp = Signal(64)
self.comb += compensated_timestamp.eq(self.cri.timestamp + (compensation << glbl_fine_ts_width))
self.sync += [
If(do_write,
If(use_laneB, current_lane.eq(current_lane + 1)),
last_coarse_timestamp.eq(coarse_timestamp),
last_lane_coarse_timestamps[use_lanen].eq(coarse_timestamp),
last_coarse_timestamp.eq(compensated_timestamp[glbl_fine_ts_width:]),
last_lane_coarse_timestamps[use_lanen].eq(compensated_timestamp[glbl_fine_ts_width:]),
seqn.eq(seqn + 1),
)
]
for lio in self.output:
self.comb += lio.payload.timestamp.eq(compensated_timestamp)
# cycle #3, read status
current_lane_writable = Signal()

3
artiq/gateware/test/rtio/test_sed_lane_distributor.py
View File

@ -10,7 +10,8 @@ LANE_COUNT = 8
def simulate(input_events, wait=True):
dut = lane_distributor.LaneDistributor(LANE_COUNT, 8, [("channel", 8), ("timestamp", 32)], 3)
dut = lane_distributor.LaneDistributor(LANE_COUNT, 8, [("channel", 8), ("timestamp", 32)],
[0]*256, 3)
output = []
access_results = []