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Add PTP clock model that generates timestamps from sim time

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Alex Forencich
2021-03-30 21:18:36 -07:00
parent 4a23d8a69c
commit a54121b503
6 changed files with 352 additions and 1 deletions
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47
README.md
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@@ -506,3 +506,50 @@ Once the clock is instantiated, it will generate a continuous stream of monotoni
* `get_ts_64()`: return current 64-bit timestamp as an integer
* `get_ts_64_ns()`: return current 64-bit timestamp in ns (float)
* `get_ts_64_s()`: return current 64-bit timestamp in seconds (float)
### PTP clock (sim time)
The `PtpClockSimTime` class implements a PTP hardware clock that produces IEEE 1588 format 96 and 64 bit PTP timestamps, derived from the current simulation time. This module can be used in place of `PtpClock` so that captured PTP timestamps can be easily compared to captured simulation time.
To use this module, import it and connect it to the DUT:
from cocotbext.eth import PtpClockSimTime
ptp_clock = PtpClockSimTime(
ts_96=dut.ts_96,
ts_64=dut.ts_64,
pps=dut.pps,
clock=dut.clk
)
Once the clock is instantiated, it will generate a continuous stream of monotonically increasing PTP timestamps on every clock edge.
#### Signals
* `ts_96`: 96-bit timestamp (48 bit seconds, 32 bit ns, 16 bit fractional ns)
* `ts_64`: 64-bit timestamp (48 bit ns, 16 bit fractional ns)
* `pps`: pulse-per-second output, pulsed when ts_96 seconds field increments
#### Constructor parameters:
* _ts_96_: 96-bit timestamp signal (optional)
* _ts_64_: 64-bit timestamp signal (optional)
* _pps_: pulse-per-second signal (optional)
* _clock_: clock
#### Attributes:
* _ts_96_s_: current 96-bit timestamp seconds field
* _ts_96_ns_: current 96-bit timestamp ns field
* _ts_96_fns_: current 96-bit timestamp fractional ns field
* _ts_64_ns_: current 64-bit timestamp ns field
* _ts_64_fns_: current 64-bit timestamp fractional ns field
#### Methods
* `get_ts_96()`: return current 96-bit timestamp as an integer
* `get_ts_96_ns()`: return current 96-bit timestamp in ns (float)
* `get_ts_96_s()`: return current 96-bit timestamp in seconds (float)
* `get_ts_64()`: return current 64-bit timestamp as an integer
* `get_ts_64_ns()`: return current 64-bit timestamp in ns (float)
* `get_ts_64_s()`: return current 64-bit timestamp in seconds (float)

2
cocotbext/eth/__init__.py
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@@ -29,4 +29,4 @@ from .mii import MiiSource, MiiSink, MiiPhy
from .rgmii import RgmiiSource, RgmiiSink, RgmiiPhy
from .xgmii import XgmiiFrame, XgmiiSource, XgmiiSink
from .ptp import PtpClock
from .ptp import PtpClock, PtpClockSimTime

77
cocotbext/eth/ptp.py
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@@ -28,6 +28,7 @@ from fractions import Fraction
import cocotb
from cocotb.triggers import RisingEdge
from cocotb.utils import get_sim_time
from .version import __version__
from .reset import Reset
@@ -253,3 +254,79 @@ class PtpClock(Reset):
self.drift_cnt -= 1
else:
self.drift_cnt = self.drift_rate-1
class PtpClockSimTime:
def __init__(self, ts_96=None, ts_64=None, pps=None, clock=None, *args, **kwargs):
self.log = logging.getLogger(f"cocotb.eth.{type(self).__name__}")
self.ts_96 = ts_96
self.ts_64 = ts_64
self.pps = pps
self.clock = clock
self.log.info("PTP clock (sim time)")
self.log.info("cocotbext-eth version %s", __version__)
self.log.info("Copyright (c) 2020 Alex Forencich")
self.log.info("https://github.com/alexforencich/cocotbext-eth")
super().__init__(*args, **kwargs)
self.ts_96_s = 0
self.ts_96_ns = 0
self.ts_96_fns = 0
self.ts_64_ns = 0
self.ts_64_fns = 0
self.last_ts_96_s = 0
if self.ts_96 is not None:
self.ts_96.setimmediatevalue(0)
if self.ts_64 is not None:
self.ts_64.setimmediatevalue(0)
if self.pps is not None:
self.pps <= 0
self._run_cr = cocotb.fork(self._run())
def get_ts_96(self):
return (self.ts_96_s << 48) | (self.ts_96_ns << 16) | self.ts_96_fns
def get_ts_96_ns(self):
return self.ts_96_s*1e9+self.ts_96_ns+self.ts_96_fns/2**16
def get_ts_96_s(self):
return self.get_ts_96_ns()*1e-9
def get_ts_64(self):
return (self.ts_64_ns << 16) | self.ts_64_fns
def get_ts_64_ns(self):
return self.get_ts_64()/2**16
def get_ts_64_s(self):
return self.get_ts_64()*1e-9
async def _run(self):
while True:
await RisingEdge(self.clock)
self.ts_64_fns, self.ts_64_ns = math.modf(get_sim_time('ns'))
self.ts_64_ns = int(self.ts_64_ns)
self.ts_64_fns = int(self.ts_64_fns*0x10000)
self.ts_96_s, self.ts_96_ns = divmod(self.ts_64_ns, 1000000000)
self.ts_96_fns = self.ts_64_fns
if self.ts_96 is not None:
self.ts_96 <= (self.ts_96_s << 48) | (self.ts_96_ns << 16) | self.ts_96_fns
if self.ts_64 is not None:
self.ts_64 <= (self.ts_64_ns << 16) | self.ts_64_fns
if self.pps is not None:
self.pps <= int(self.last_ts_96_s != self.ts_96_s)
self.last_ts_96_s = self.ts_96_s

61
tests/ptp_clock_sim_time/Makefile Normal file
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@@ -0,0 +1,61 @@
# Copyright (c) 2020 Alex Forencich
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
TOPLEVEL_LANG = verilog
SIM ?= icarus
WAVES ?= 0
COCOTB_HDL_TIMEUNIT = 1ns
COCOTB_HDL_TIMEPRECISION = 1ps
DUT = test_ptp_clock_sim_time
TOPLEVEL = $(DUT)
MODULE = $(DUT)
VERILOG_SOURCES += $(DUT).v
ifeq ($(SIM), icarus)
PLUSARGS += -fst
ifeq ($(WAVES), 1)
VERILOG_SOURCES += iverilog_dump.v
COMPILE_ARGS += -s iverilog_dump
endif
else ifeq ($(SIM), verilator)
COMPILE_ARGS += -Wno-SELRANGE -Wno-WIDTH
ifeq ($(WAVES), 1)
COMPILE_ARGS += --trace-fst
endif
endif
include $(shell cocotb-config --makefiles)/Makefile.sim
iverilog_dump.v:
echo 'module iverilog_dump();' > $@
echo 'initial begin' >> $@
echo ' $$dumpfile("$(TOPLEVEL).fst");' >> $@
echo ' $$dumpvars(0, $(TOPLEVEL));' >> $@
echo 'end' >> $@
echo 'endmodule' >> $@
clean::
@rm -rf iverilog_dump.v
@rm -rf dump.fst $(TOPLEVEL).fst

125
tests/ptp_clock_sim_time/test_ptp_clock_sim_time.py Normal file
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@@ -0,0 +1,125 @@
#!/usr/bin/env python
"""
Copyright (c) 2021 Alex Forencich
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
"""
import logging
import os
import cocotb_test.simulator
import cocotb
from cocotb.clock import Clock
from cocotb.triggers import RisingEdge
from cocotb.utils import get_sim_time
from cocotbext.eth import PtpClockSimTime
class TB:
def __init__(self, dut):
self.dut = dut
self.log = logging.getLogger("cocotb.tb")
self.log.setLevel(logging.DEBUG)
cocotb.fork(Clock(dut.clk, 6.4, units="ns").start())
self.ptp_clock = PtpClockSimTime(
ts_96=dut.ts_96,
ts_64=dut.ts_64,
pps=dut.pps,
clock=dut.clk
)
@cocotb.test()
async def run_test(dut):
tb = TB(dut)
await RisingEdge(dut.clk)
await RisingEdge(dut.clk)
await RisingEdge(dut.clk)
start_time = get_sim_time('sec')
start_ts_96 = (dut.ts_96.value.integer >> 48) + ((dut.ts_96.value.integer & 0xffffffffffff)/2**16*1e-9)
start_ts_64 = dut.ts_64.value.integer/2**16*1e-9
for k in range(10000):
await RisingEdge(dut.clk)
stop_time = get_sim_time('sec')
stop_ts_96 = (dut.ts_96.value.integer >> 48) + ((dut.ts_96.value.integer & 0xffffffffffff)/2**16*1e-9)
stop_ts_64 = dut.ts_64.value.integer/2**16*1e-9
time_delta = stop_time-start_time
ts_96_delta = stop_ts_96-start_ts_96
ts_64_delta = stop_ts_64-start_ts_64
ts_96_diff = time_delta - ts_96_delta
ts_64_diff = time_delta - ts_64_delta
tb.log.info("sim time delta : %g s", time_delta)
tb.log.info("96 bit ts delta : %g s", ts_96_delta)
tb.log.info("64 bit ts delta : %g s", ts_64_delta)
tb.log.info("96 bit ts diff : %g s", ts_96_diff)
tb.log.info("64 bit ts diff : %g s", ts_64_diff)
assert abs(ts_96_diff) < 1e-12
assert abs(ts_64_diff) < 1e-12
await RisingEdge(dut.clk)
await RisingEdge(dut.clk)
# cocotb-test
tests_dir = os.path.dirname(__file__)
def test_ptp_clock(request):
dut = "test_ptp_clock_sim_time"
module = os.path.splitext(os.path.basename(__file__))[0]
toplevel = dut
verilog_sources = [
os.path.join(tests_dir, f"{dut}.v"),
]
parameters = {}
extra_env = {f'PARAM_{k}': str(v) for k, v in parameters.items()}
sim_build = os.path.join(tests_dir, "sim_build",
request.node.name.replace('[', '-').replace(']', ''))
cocotb_test.simulator.run(
python_search=[tests_dir],
verilog_sources=verilog_sources,
toplevel=toplevel,
module=module,
parameters=parameters,
sim_build=sim_build,
extra_env=extra_env,
)

41
tests/ptp_clock_sim_time/test_ptp_clock_sim_time.v Normal file
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@@ -0,0 +1,41 @@
/*
Copyright (c) 2021 Alex Forencich
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
// Language: Verilog 2001
`timescale 1ns / 1ps
/*
* PTP clock test
*/
module test_ptp_clock_sim_time
(
input wire clk,
inout wire [95:0] ts_96,
inout wire [63:0] ts_64,
inout wire pps
);
endmodule