ptp: Add PTP TD PHC module and testbench

Signed-off-by: Alex Forencich <alex@alexforencich.com>

tb/ptp/taxi_ptp_td_phc/Makefile

@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: CERN-OHL-S-2.0
+#
+# Copyright (c) 2023-2025 FPGA Ninja, LLC
+#
+# Authors:
+# - Alex Forencich
+
+TOPLEVEL_LANG = verilog
+
+SIM ?= verilator
+WAVES ?= 0
+
+COCOTB_HDL_TIMEUNIT = 1ns
+COCOTB_HDL_TIMEPRECISION = 1ps
+
+DUT      = taxi_ptp_td_phc
+COCOTB_TEST_MODULES = test_$(DUT)
+COCOTB_TOPLEVEL     = $(DUT)
+MODULE   = $(COCOTB_TEST_MODULES)
+TOPLEVEL = $(COCOTB_TOPLEVEL)
+VERILOG_SOURCES += ../../../rtl/ptp/$(DUT).sv
+
+# handle file list files
+process_f_file = $(call process_f_files,$(addprefix $(dir $1),$(shell cat $1)))
+process_f_files = $(foreach f,$1,$(if $(filter %.f,$f),$(call process_f_file,$f),$f))
+uniq_base = $(if $1,$(call uniq_base,$(foreach f,$1,$(if $(filter-out $(notdir $(lastword $1)),$(notdir $f)),$f,))) $(lastword $1))
+VERILOG_SOURCES := $(call uniq_base,$(call process_f_files,$(VERILOG_SOURCES)))
+
+# module parameters
+export PARAM_PERIOD_NS_NUM := 32
+export PARAM_PERIOD_NS_DENOM := 5
+
+ifeq ($(SIM), icarus)
+	PLUSARGS += -fst
+
+	COMPILE_ARGS += $(foreach v,$(filter PARAM_%,$(.VARIABLES)),-P $(COCOTB_TOPLEVEL).$(subst PARAM_,,$(v))=$($(v)))
+else ifeq ($(SIM), verilator)
+	COMPILE_ARGS += $(foreach v,$(filter PARAM_%,$(.VARIABLES)),-G$(subst PARAM_,,$(v))=$($(v)))
+
+	ifeq ($(WAVES), 1)
+		COMPILE_ARGS += --trace-fst
+		VERILATOR_TRACE = 1
+	endif
+endif
+
+include $(shell cocotb-config --makefiles)/Makefile.sim

tb/ptp/taxi_ptp_td_phc/ptp_td.py

@@ -0,0 +1 @@
+../ptp_td.py

tb/ptp/taxi_ptp_td_phc/test_taxi_ptp_td_phc.py

@@ -0,0 +1,550 @@
+#!/usr/bin/env python
+# SPDX-License-Identifier: CERN-OHL-S-2.0
+"""
+
+Copyright (c) 2023-2025 FPGA Ninja, LLC
+
+Authors:
+- Alex Forencich
+
+"""
+
+import logging
+import os
+import sys
+from decimal import Decimal
+
+import cocotb_test.simulator
+
+import cocotb
+from cocotb.clock import Clock
+from cocotb.triggers import RisingEdge
+from cocotb.utils import get_sim_time
+
+try:
+    from ptp_td import PtpTdSink
+except ImportError:
+    # attempt import from current directory
+    sys.path.insert(0, os.path.join(os.path.dirname(__file__)))
+    try:
+        from ptp_td import PtpTdSink
+    finally:
+        del sys.path[0]
+
+
+class TB:
+    def __init__(self, dut):
+        self.dut = dut
+
+        self.log = logging.getLogger("cocotb.tb")
+        self.log.setLevel(logging.DEBUG)
+
+        cocotb.start_soon(Clock(dut.clk, 6.4, units="ns").start())
+
+        self.ptp_td_sink = PtpTdSink(
+            data=dut.ptp_td_sdo,
+            clock=dut.clk,
+            reset=dut.rst,
+            period_ns=6.4
+        )
+
+        dut.input_ts_rel_ns.setimmediatevalue(0)
+        dut.input_ts_rel_valid.setimmediatevalue(0)
+        dut.input_ts_rel_offset_ns.setimmediatevalue(0)
+        dut.input_ts_rel_offset_valid.setimmediatevalue(0)
+
+        dut.input_ts_tod_s.setimmediatevalue(0)
+        dut.input_ts_tod_ns.setimmediatevalue(0)
+        dut.input_ts_tod_valid.setimmediatevalue(0)
+        dut.input_ts_tod_offset_ns.setimmediatevalue(0)
+        dut.input_ts_tod_offset_valid.setimmediatevalue(0)
+
+        dut.input_ts_offset_fns.setimmediatevalue(0)
+        dut.input_ts_offset_valid.setimmediatevalue(0)
+
+        dut.input_period_ns.setimmediatevalue(0)
+        dut.input_period_fns.setimmediatevalue(0)
+        dut.input_period_valid.setimmediatevalue(0)
+        dut.input_drift_num.setimmediatevalue(0)
+        dut.input_drift_denom.setimmediatevalue(0)
+        dut.input_drift_valid.setimmediatevalue(0)
+
+    async def reset(self):
+        self.dut.rst.setimmediatevalue(0)
+        await RisingEdge(self.dut.clk)
+        await RisingEdge(self.dut.clk)
+        self.dut.rst.value = 1
+        await RisingEdge(self.dut.clk)
+        await RisingEdge(self.dut.clk)
+        self.dut.rst.value = 0
+        await RisingEdge(self.dut.clk)
+        await RisingEdge(self.dut.clk)
+
+
+@cocotb.test()
+async def run_default_rate(dut):
+
+    tb = TB(dut)
+
+    await tb.reset()
+
+    for k in range(256*6):
+        await RisingEdge(dut.clk)
+
+    await RisingEdge(dut.clk)
+    start_time = Decimal(get_sim_time('fs')).scaleb(-6)
+    start_ts_tod = tb.ptp_td_sink.get_ts_tod_ns()
+    start_ts_rel = tb.ptp_td_sink.get_ts_rel_ns()
+
+    for k in range(10000):
+        await RisingEdge(dut.clk)
+
+    stop_time = Decimal(get_sim_time('fs')).scaleb(-6)
+    stop_ts_tod = tb.ptp_td_sink.get_ts_tod_ns()
+    stop_ts_rel = tb.ptp_td_sink.get_ts_rel_ns()
+
+    time_delta = stop_time-start_time
+    ts_tod_delta = stop_ts_tod-start_ts_tod
+    ts_rel_delta = stop_ts_rel-start_ts_rel
+
+    tb.log.info("sim time delta : %s ns", time_delta)
+    tb.log.info("ToD ts delta   : %s ns", ts_tod_delta)
+    tb.log.info("Rel ts delta   : %s ns", ts_rel_delta)
+
+    ts_tod_diff = time_delta - ts_tod_delta
+    ts_rel_diff = time_delta - ts_rel_delta
+
+    tb.log.info("ToD ts diff    : %s ns", ts_tod_diff)
+    tb.log.info("Rel ts diff    : %s ns", ts_rel_diff)
+
+    assert abs(ts_tod_diff) < 1e-3
+    assert abs(ts_rel_diff) < 1e-3
+
+    await RisingEdge(dut.clk)
+    await RisingEdge(dut.clk)
+
+
+@cocotb.test()
+async def run_load_timestamps(dut):
+
+    tb = TB(dut)
+
+    await tb.reset()
+
+    await RisingEdge(dut.clk)
+
+    dut.input_ts_tod_s.value = 12
+    dut.input_ts_tod_ns.value = 123456789
+    dut.input_ts_tod_valid.value = 1
+
+    await RisingEdge(dut.clk)
+    while not dut.input_ts_tod_ready.value:
+        await RisingEdge(dut.clk)
+
+    dut.input_ts_tod_valid.value = 0
+
+    dut.input_ts_rel_ns.value = 123456789
+    dut.input_ts_rel_valid.value = 1
+
+    await RisingEdge(dut.clk)
+    while not dut.input_ts_rel_ready.value:
+        await RisingEdge(dut.clk)
+
+    dut.input_ts_rel_valid.value = 0
+
+    for k in range(256*6):
+        await RisingEdge(dut.clk)
+
+    # assert tb.ptp_td_sink.get_ts_tod_s() - (12.123456789 + (256*6-(14*17+32)-2)*6.4e-9) < 6.4e-9
+    # assert tb.ptp_td_sink.get_ts_rel_ns() - (123456789 + (256*6-(14*17+32)-1)*6.4) < 6.4
+
+    await RisingEdge(dut.clk)
+    start_time = Decimal(get_sim_time('fs')).scaleb(-6)
+    start_ts_tod = tb.ptp_td_sink.get_ts_tod_ns()
+    start_ts_rel = tb.ptp_td_sink.get_ts_rel_ns()
+
+    for k in range(10000):
+        await RisingEdge(dut.clk)
+
+    stop_time = Decimal(get_sim_time('fs')).scaleb(-6)
+    stop_ts_tod = tb.ptp_td_sink.get_ts_tod_ns()
+    stop_ts_rel = tb.ptp_td_sink.get_ts_rel_ns()
+
+    time_delta = stop_time-start_time
+    ts_tod_delta = stop_ts_tod-start_ts_tod
+    ts_rel_delta = stop_ts_rel-start_ts_rel
+
+    tb.log.info("sim time delta : %s ns", time_delta)
+    tb.log.info("ToD ts delta   : %s ns", ts_tod_delta)
+    tb.log.info("Rel ts delta   : %s ns", ts_rel_delta)
+
+    ts_tod_diff = time_delta - ts_tod_delta
+    ts_rel_diff = time_delta - ts_rel_delta
+
+    tb.log.info("ToD ts diff    : %s ns", ts_tod_diff)
+    tb.log.info("Rel ts diff    : %s ns", ts_rel_diff)
+
+    assert abs(ts_tod_diff) < 1e-3
+    assert abs(ts_rel_diff) < 1e-3
+
+    await RisingEdge(dut.clk)
+    await RisingEdge(dut.clk)
+
+
+@cocotb.test()
+async def run_offsets(dut):
+
+    tb = TB(dut)
+
+    await tb.reset()
+
+    for k in range(256*6):
+        await RisingEdge(dut.clk)
+
+    await RisingEdge(dut.clk)
+    start_time = Decimal(get_sim_time('fs')).scaleb(-6)
+    start_ts_tod = tb.ptp_td_sink.get_ts_tod_ns()
+    start_ts_rel = tb.ptp_td_sink.get_ts_rel_ns()
+
+    for k in range(2000):
+        await RisingEdge(dut.clk)
+
+    tb.log.info("Offset FNS (positive)")
+
+    await RisingEdge(dut.clk)
+
+    dut.input_ts_offset_fns.value = 0x78000000 & 0xffffffff
+    dut.input_ts_offset_valid.value = 1
+
+    await RisingEdge(dut.clk)
+    while not dut.input_ts_offset_ready.value:
+        await RisingEdge(dut.clk)
+
+    dut.input_ts_offset_valid.value = 0
+
+    for k in range(2000):
+        await RisingEdge(dut.clk)
+
+    tb.log.info("Offset FNS (negative)")
+
+    await RisingEdge(dut.clk)
+
+    dut.input_ts_offset_fns.value = -0x70000000 & 0xffffffff
+    dut.input_ts_offset_valid.value = 1
+
+    await RisingEdge(dut.clk)
+    while not dut.input_ts_offset_ready.value:
+        await RisingEdge(dut.clk)
+
+    dut.input_ts_offset_valid.value = 0
+
+    for k in range(2000):
+        await RisingEdge(dut.clk)
+
+    tb.log.info("Offset relative TS (positive)")
+
+    dut.input_ts_rel_offset_ns.value = 30000 & 0xffffffff
+    dut.input_ts_rel_offset_valid.value = 1
+
+    await RisingEdge(dut.clk)
+    while not dut.input_ts_rel_offset_ready.value:
+        await RisingEdge(dut.clk)
+
+    dut.input_ts_rel_offset_valid.value = 0
+
+    for k in range(2000):
+        await RisingEdge(dut.clk)
+
+    tb.log.info("Offset relative TS (negative)")
+
+    dut.input_ts_rel_offset_ns.value = -10000 & 0xffffffff
+    dut.input_ts_rel_offset_valid.value = 1
+
+    await RisingEdge(dut.clk)
+    while not dut.input_ts_rel_offset_ready.value:
+        await RisingEdge(dut.clk)
+
+    dut.input_ts_rel_offset_valid.value = 0
+
+    for k in range(2000):
+        await RisingEdge(dut.clk)
+
+    tb.log.info("Offset ToD TS (positive)")
+
+    dut.input_ts_tod_offset_ns.value = 510000000 & 0x3fffffff
+    dut.input_ts_tod_offset_valid.value = 1
+
+    await RisingEdge(dut.clk)
+    while not dut.input_ts_tod_offset_ready.value:
+        await RisingEdge(dut.clk)
+
+    await RisingEdge(dut.clk)
+    while not dut.input_ts_tod_offset_ready.value:
+        await RisingEdge(dut.clk)
+
+    dut.input_ts_tod_offset_valid.value = 0
+
+    for k in range(2000):
+        await RisingEdge(dut.clk)
+
+    tb.log.info("Offset ToD TS (negative)")
+
+    dut.input_ts_tod_offset_ns.value = -500000000 & 0x3fffffff
+    dut.input_ts_tod_offset_valid.value = 1
+
+    await RisingEdge(dut.clk)
+    while not dut.input_ts_tod_offset_ready.value:
+        await RisingEdge(dut.clk)
+
+    await RisingEdge(dut.clk)
+    while not dut.input_ts_tod_offset_ready.value:
+        await RisingEdge(dut.clk)
+
+    dut.input_ts_tod_offset_valid.value = 0
+
+    for k in range(10000):
+        await RisingEdge(dut.clk)
+
+    stop_time = Decimal(get_sim_time('fs')).scaleb(-6)
+    stop_ts_tod = tb.ptp_td_sink.get_ts_tod_ns()
+    stop_ts_rel = tb.ptp_td_sink.get_ts_rel_ns()
+
+    time_delta = stop_time-start_time
+    ts_tod_delta = stop_ts_tod-start_ts_tod
+    ts_rel_delta = stop_ts_rel-start_ts_rel
+
+    tb.log.info("sim time delta : %s ns", time_delta)
+    tb.log.info("ToD ts delta   : %s ns", ts_tod_delta)
+    tb.log.info("Rel ts delta   : %s ns", ts_rel_delta)
+
+    ts_tod_diff = time_delta - ts_tod_delta + Decimal(0.03125) + Decimal(20000000)
+    ts_rel_diff = time_delta - ts_rel_delta + Decimal(0.03125) + Decimal(20000)
+
+    tb.log.info("ToD ts diff    : %s ns", ts_tod_diff)
+    tb.log.info("Rel ts diff    : %s ns", ts_rel_diff)
+
+    assert abs(ts_tod_diff) < 1e-3
+    assert abs(ts_rel_diff) < 1e-3
+
+    await RisingEdge(dut.clk)
+    await RisingEdge(dut.clk)
+
+
+@cocotb.test()
+async def run_seconds_increment(dut):
+
+    tb = TB(dut)
+
+    await tb.reset()
+
+    await RisingEdge(dut.clk)
+
+    dut.input_ts_tod_s.value = 0
+    dut.input_ts_tod_ns.value = 999990000
+    dut.input_ts_tod_valid.value = 1
+
+    await RisingEdge(dut.clk)
+    while not dut.input_ts_tod_ready.value:
+        await RisingEdge(dut.clk)
+
+    dut.input_ts_tod_valid.value = 0
+
+    for k in range(256*6):
+        await RisingEdge(dut.clk)
+
+    await RisingEdge(dut.clk)
+    start_time = Decimal(get_sim_time('fs')).scaleb(-6)
+    start_ts_tod = tb.ptp_td_sink.get_ts_tod_ns()
+    start_ts_rel = tb.ptp_td_sink.get_ts_rel_ns()
+
+    saw_pps = False
+
+    for k in range(3000):
+        await RisingEdge(dut.clk)
+
+        if dut.output_pps.value.integer:
+            saw_pps = True
+            tb.log.info("Got PPS with sink ToD TS %s", tb.ptp_td_sink.get_ts_tod_ns())
+            assert (tb.ptp_td_sink.get_ts_tod_s() - 1) < 6.4e-9
+
+    assert saw_pps
+
+    stop_time = Decimal(get_sim_time('fs')).scaleb(-6)
+    stop_ts_tod = tb.ptp_td_sink.get_ts_tod_ns()
+    stop_ts_rel = tb.ptp_td_sink.get_ts_rel_ns()
+
+    time_delta = stop_time-start_time
+    ts_tod_delta = stop_ts_tod-start_ts_tod
+    ts_rel_delta = stop_ts_rel-start_ts_rel
+
+    tb.log.info("sim time delta : %s ns", time_delta)
+    tb.log.info("ToD ts delta   : %s ns", ts_tod_delta)
+    tb.log.info("Rel ts delta   : %s ns", ts_rel_delta)
+
+    ts_tod_diff = time_delta - ts_tod_delta
+    ts_rel_diff = time_delta - ts_rel_delta
+
+    tb.log.info("ToD ts diff    : %s ns", ts_tod_diff)
+    tb.log.info("Rel ts diff    : %s ns", ts_rel_diff)
+
+    assert abs(ts_tod_diff) < 1e-3
+    assert abs(ts_rel_diff) < 1e-3
+
+    await RisingEdge(dut.clk)
+    await RisingEdge(dut.clk)
+
+
+@cocotb.test()
+async def run_frequency_adjustment(dut):
+
+    tb = TB(dut)
+
+    await tb.reset()
+
+    await RisingEdge(dut.clk)
+
+    dut.input_period_ns.value = 0x6
+    dut.input_period_fns.value = 0x66240000
+    dut.input_period_valid.value = 1
+
+    await RisingEdge(dut.clk)
+
+    dut.input_period_valid.value = 0
+
+    for k in range(256*6):
+        await RisingEdge(dut.clk)
+
+    await RisingEdge(dut.clk)
+    start_time = Decimal(get_sim_time('fs')).scaleb(-6)
+    start_ts_tod = tb.ptp_td_sink.get_ts_tod_ns()
+    start_ts_rel = tb.ptp_td_sink.get_ts_rel_ns()
+
+    for k in range(10000):
+        await RisingEdge(dut.clk)
+
+    stop_time = Decimal(get_sim_time('fs')).scaleb(-6)
+    stop_ts_tod = tb.ptp_td_sink.get_ts_tod_ns()
+    stop_ts_rel = tb.ptp_td_sink.get_ts_rel_ns()
+
+    time_delta = stop_time-start_time
+    ts_tod_delta = stop_ts_tod-start_ts_tod
+    ts_rel_delta = stop_ts_rel-start_ts_rel
+
+    tb.log.info("sim time delta : %s ns", time_delta)
+    tb.log.info("ToD ts delta   : %s ns", ts_tod_delta)
+    tb.log.info("Rel ts delta   : %s ns", ts_rel_delta)
+
+    ts_tod_diff = time_delta - ts_tod_delta * Decimal(6.4/(6+(0x66240000+2/5)/2**32))
+    ts_rel_diff = time_delta - ts_rel_delta * Decimal(6.4/(6+(0x66240000+2/5)/2**32))
+
+    tb.log.info("ToD ts diff    : %s ns", ts_tod_diff)
+    tb.log.info("Rel ts diff    : %s ns", ts_rel_diff)
+
+    assert abs(ts_tod_diff) < 1e-3
+    assert abs(ts_rel_diff) < 1e-3
+
+    await RisingEdge(dut.clk)
+    await RisingEdge(dut.clk)
+
+
+@cocotb.test()
+async def run_drift_adjustment(dut):
+
+    tb = TB(dut)
+
+    await tb.reset()
+
+    dut.input_drift_num.value = 20000
+    dut.input_drift_denom.value = 5
+    dut.input_drift_valid.value = 1
+
+    await RisingEdge(dut.clk)
+
+    dut.input_drift_valid.value = 0
+
+    for k in range(256*6):
+        await RisingEdge(dut.clk)
+
+    await RisingEdge(dut.clk)
+    start_time = Decimal(get_sim_time('fs')).scaleb(-6)
+    start_ts_tod = tb.ptp_td_sink.get_ts_tod_ns()
+    start_ts_rel = tb.ptp_td_sink.get_ts_rel_ns()
+
+    for k in range(10000):
+        await RisingEdge(dut.clk)
+
+    stop_time = Decimal(get_sim_time('fs')).scaleb(-6)
+    stop_ts_tod = tb.ptp_td_sink.get_ts_tod_ns()
+    stop_ts_rel = tb.ptp_td_sink.get_ts_rel_ns()
+
+    time_delta = stop_time-start_time
+    ts_tod_delta = stop_ts_tod-start_ts_tod
+    ts_rel_delta = stop_ts_rel-start_ts_rel
+
+    tb.log.info("sim time delta : %s ns", time_delta)
+    tb.log.info("ToD ts delta   : %s ns", ts_tod_delta)
+    tb.log.info("Rel ts delta   : %s ns", ts_rel_delta)
+
+    ts_tod_diff = time_delta - ts_tod_delta * Decimal(6.4/(6+(0x66666666+20000/5)/2**32))
+    ts_rel_diff = time_delta - ts_rel_delta * Decimal(6.4/(6+(0x66666666+20000/5)/2**32))
+
+    tb.log.info("ToD ts diff    : %s ns", ts_tod_diff)
+    tb.log.info("Rel ts diff    : %s ns", ts_rel_diff)
+
+    assert abs(ts_tod_diff) < 1e-3
+    assert abs(ts_rel_diff) < 1e-3
+
+    await RisingEdge(dut.clk)
+    await RisingEdge(dut.clk)
+
+
+# cocotb-test
+
+tests_dir = os.path.abspath(os.path.dirname(__file__))
+rtl_dir = os.path.abspath(os.path.join(tests_dir, '..', '..', '..', 'rtl'))
+
+
+def process_f_files(files):
+    lst = {}
+    for f in files:
+        if f[-2:].lower() == '.f':
+            with open(f, 'r') as fp:
+                l = fp.read().split()
+            for f in process_f_files([os.path.join(os.path.dirname(f), x) for x in l]):
+                lst[os.path.basename(f)] = f
+        else:
+            lst[os.path.basename(f)] = f
+    return list(lst.values())
+
+
+def test_taxi_ptp_td_phc(request):
+    dut = "taxi_ptp_td_phc"
+    module = os.path.splitext(os.path.basename(__file__))[0]
+    toplevel = dut
+
+    verilog_sources = [
+        os.path.join(rtl_dir, "ptp", f"{dut}.sv"),
+    ]
+
+    verilog_sources = process_f_files(verilog_sources)
+
+    parameters = {}
+
+    parameters['PERIOD_NS_NUM'] = 32
+    parameters['PERIOD_NS_DENOM'] = 5
+
+    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(
+        simulator="verilator",
+        python_search=[tests_dir],
+        verilog_sources=verilog_sources,
+        toplevel=toplevel,
+        module=module,
+        parameters=parameters,
+        sim_build=sim_build,
+        extra_env=extra_env,
+    )