DART-6UL Eth IEEE.1588
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DART-6UL - IEEE 1588 Hardware Timestamp
Overview of IEEE 1588 Hardware Timestamping
We recommend getting the basic overview of the IEE1588 and timestamping and basic terminologies.
Refer to https://elinux.org/images/f/f9/Introduction_to_IEEE_1588_Precision_Time_Protocol_%28PTP%29_Using_Embedded_Linux_Systems.pdf
At the very top level, it can be described as below
NXP Supports IEE1588 PTP implemented in the Ethernet SOC MAC layer.
File:IEEE Block Diagram IMX6.png
Above diagram depicts the implementation of hardware timestamping at the SOC level.
The programmable Ethernet MAC with IEEE 1588 integrates a standard IEEE 802.3. controller
Ethernet MAC with a time-stamping module, with IEEE 1588 standard provides accurate.
clock synchronization for distributed control nodes for industrial automation applications.
NXP IEE1588 PTP and timer implementation have below features:
- Allows reference clock to be chosen independently of network speed.
- Software-programmable precise time-stamping of ingress and egress frames.
- Timer monitoring capabilities for system calibration and timing accuracy management.
- Precise time-stamping of external events with programmable interrupt generation.
- Programmable event and interrupt generation for external system control.
- Supports hardware and software-controllable timer synchronization.
- Provides a 4-channel IEEE 1588 timer. Each channel supports input capture and output compare using the 1588 counter.
- Distribution of precise time information over the packet-based network.
- Offers high accuracy (in the sub-microsecond range) over the net
Hardware Setup
- Network Setup: Connect the PC/Grand Master Clock Source and the target to the same Ethernet network (and use ping to verify the connection between the PC and the target).
Software
In the current setup, we will have
- PC - Grand Master which acts as the clock source which has the GPS clock synchronized
Note: You may choose Device (i.MX6UL) as grandmaster clock as a device as well.
- Device - i.MX8 with IEE1588 HW timestamp support - of which local clock to be synchronized with grandmaster
On PC (Master)
Software utilities required for PTP
$ ptp4l $ phc2sys
For Ubuntu 16.04
$ sudo apt-get install linuxptp
Start the software base timestamping on PC or to become grandmaster clock source which you want to synchronize.
Make sure you have following device tree change present on your kernel.
Note that in this example, ENET2_EVENT0_OUT is supported so only hardware event is feasible.
For more details, see https://www.variscite.com/wp-content/uploads/2018/01/DART-6UL_DART-6UL-5G_Datasheet.pdf
for all combination of IEE1588 events and pinmuxing.
diff --git a/arch/arm/boot/dts/imx6ul-imx6ull-var-dart-common.dtsi b/arch/arm/boot/dts/imx6ul-imx6ull-var-dart-common.dtsi
index f9170af..7182f97 100644
--- a/arch/arm/boot/dts/imx6ul-imx6ull-var-dart-common.dtsi
+++ b/arch/arm/boot/dts/imx6ul-imx6ull-var-dart-common.dtsi
@@ -487,6 +487,7 @@
MX6UL_PAD_ENET2_TX_DATA1__ENET2_TDATA01 0x1b0b0
MX6UL_PAD_ENET2_TX_CLK__ENET2_REF_CLK2 0x4001b031
MX6UL_PAD_JTAG_MOD__GPIO1_IO10 0x1b0b0
+ MX6UL_PAD_GPIO1_IO05__ENET2_1588_EVENT0_OUT 0x1b0b0
>;
};
$ sudo ptp4l -i enp5s0 -m -S
- Here, in this case, the PC sends the timestamp using software timer.
- The timestamp packets are sent over networking infrastructure via switch/router (IEEE 1588 packets)
and then once received on the target, it is used to synchronize the clock with 1μs accuracy.
- Hardware has the test and compares logic to see the drift and jitter.
Testing on device side
ptp4l works as a daemon service. It must be started first before any system level PTP client can work.
Yocto build already contains the ptp4l required resoureces on the target.
Run following commands on target
root@imx6ul-var-dart:~# ptp4l -H -A -l 7 -q -i eth1 -m -s ptp4l[151.372]: config item (null).assume_two_step is 0 ptp4l[151.373]: config item (null).check_fup_sync is 0 ptp4l[151.374]: config item (null).tx_timestamp_timeout is 1 ptp4l[151.375]: config item (null).clock_servo is 0 ptp4l[151.376]: config item (null).time_stamping is 1 ptp4l[151.378]: config item (null).clock_servo is 0 ptp4l[151.379]: config item (null).clockClass is 248 ptp4l[151.380]: config item (null).clockAccuracy is 254 ptp4l[151.381]: config item (null).offsetScaledLogVariance is 65535 ptp4l[151.382]: config item (null).productDescription is ';;' ptp4l[151.383]: config item (null).revisionData is ';;' ptp4l[151.383]: config item (null).userDescription is '' ptp4l[151.383]: config item (null).manufacturerIdentity is '00:00:00' ptp4l[151.384]: config item (null).domainNumber is 0 ptp4l[151.385]: config item (null).slaveOnly is 1 ptp4l[151.385]: config item (null).twoStepFlag is 1 ptp4l[151.385]: config item (null).priority1 is 128 ptp4l[151.385]: config item (null).priority2 is 128 ptp4l[151.385]: config item (null).gmCapable is 1 ptp4l[151.386]: config item (null).gmCapable is 1 ptp4l[151.387]: config item (null).free_running is 0 ptp4l[151.387]: selected /dev/ptp1 as PTP clock ptp4l[151.387]: config item (null).uds_address is '/var/run/ptp4l' ptp4l[151.389]: section item /var/run/ptp4l.announceReceiptTimeout now 0 ptp4l[151.389]: section item /var/run/ptp4l.delay_mechanism now 0 ptp4l[151.389]: section item /var/run/ptp4l.network_transport now 0 ptp4l[151.389]: section item /var/run/ptp4l.delay_filter_length now 1 ptp4l[151.390]: config item (null).free_running is 0 ptp4l[151.390]: config item (null).freq_est_interval is 1 ptp4l[151.391]: config item (null).gmCapable is 1 ptp4l[151.392]: config item (null).kernel_leap is 1 ptp4l[151.392]: config item (null).timeSource is 160 ptp4l[151.392]: config item (null).pi_proportional_const is 0.000000 ptp4l[151.393]: config item (null).pi_integral_const is 0.000000 ptp4l[151.393]: config item (null).pi_proportional_scale is 0.000000 ptp4l[151.393]: config item (null).pi_proportional_exponent is -0.300000 ptp4l[151.393]: config item (null).pi_proportional_norm_max is 0.700000 ptp4l[151.393]: config item (null).pi_integral_scale is 0.000000 ptp4l[151.394]: config item (null).pi_integral_exponent is 0.400000 ptp4l[151.394]: config item (null).pi_integral_norm_max is 0.300000 ptp4l[151.394]: config item (null).step_threshold is 0.000000 ptp4l[151.394]: config item (null).first_step_threshold is 0.000020 ptp4l[151.394]: config item (null).max_frequency is 900000000 ptp4l[151.395]: config item (null).tsproc_mode is 0 ptp4l[151.395]: config item (null).delay_filter is 1 ptp4l[151.395]: config item (null).delay_filter_length is 10 ptp4l[151.395]: config item (null).summary_interval is 0 ptp4l[151.395]: config item (null).sanity_freq_limit is 200000000 ptp4l[151.396]: PI servo: sync interval 1.000 kp 0.700 ki 0.300000 ptp4l[151.396]: config item /var/run/ptp4l.boundary_clock_jbod is 0 ptp4l[151.397]: config item /var/run/ptp4l.network_transport is 0 ptp4l[151.397]: config item /var/run/ptp4l.delayAsymmetry is 0 ptp4l[151.397]: config item /var/run/ptp4l.follow_up_info is 0 ptp4l[151.397]: config item /var/run/ptp4l.freq_est_interval is 1 ptp4l[151.398]: config item /var/run/ptp4l.hybrid_e2e is 0 ptp4l[151.398]: config item /var/run/ptp4l.path_trace_enabled is 0 ptp4l[151.398]: config item /var/run/ptp4l.ingressLatency is 0 ptp4l[151.398]: config item /var/run/ptp4l.egressLatency is 0 ptp4l[151.398]: config item /var/run/ptp4l.delay_mechanism is 0 ptp4l[151.399]: config item /var/run/ptp4l.fault_badpeernet_interval is 16 ptp4l[151.399]: config item /var/run/ptp4l.fault_reset_interval is 4 ptp4l[151.399]: config item /var/run/ptp4l.tsproc_mode is 0 ptp4l[151.399]: config item /var/run/ptp4l.delay_filter is 1 ptp4l[151.399]: config item /var/run/ptp4l.delay_filter_length is 1 ptp4l[151.400]: config item eth1.boundary_clock_jbod is 0 ptp4l[151.400]: config item eth1.network_transport is 1 ptp4l[151.401]: config item eth1.delayAsymmetry is 0 ptp4l[151.401]: config item eth1.follow_up_info is 0 ptp4l[151.401]: config item eth1.freq_est_interval is 1 ptp4l[151.401]: config item eth1.hybrid_e2e is 0 ptp4l[151.401]: config item eth1.path_trace_enabled is 0 ptp4l[151.401]: config item eth1.ingressLatency is 0 ptp4l[151.401]: config item eth1.egressLatency is 0 ptp4l[151.401]: config item eth1.delay_mechanism is 0 ptp4l[151.402]: config item eth1.fault_badpeernet_interval is 16 ptp4l[151.403]: config item eth1.fault_reset_interval is 4 ptp4l[151.403]: config item eth1.tsproc_mode is 0 ptp4l[151.403]: config item eth1.delay_filter is 1 ptp4l[151.403]: config item eth1.delay_filter_length is 10 ptp4l[151.404]: config item eth1.logMinDelayReqInterval is 0 ptp4l[151.405]: config item eth1.logAnnounceInterval is 1 ptp4l[151.405]: config item eth1.announceReceiptTimeout is 3 ptp4l[151.405]: config item eth1.syncReceiptTimeout is 0 ptp4l[151.405]: config item eth1.transportSpecific is 0 ptp4l[151.405]: config item eth1.logSyncInterval is 0 ptp4l[151.406]: config item eth1.logMinPdelayReqInterval is 0 ptp4l[151.406]: config item eth1.neighborPropDelayThresh is 20000000 ptp4l[151.406]: config item eth1.min_neighbor_prop_delay is -20000000 ptp4l[151.406]: config item eth1.udp_ttl is 1 ptp4l[151.409]: driver changed our HWTSTAMP options ptp4l[151.410]: tx_type 1 not 1 ptp4l[151.411]: rx_filter 1 not 12 ptp4l[151.411]: config item (null).dscp_event is 0 ptp4l[151.412]: config item (null).dscp_general is 0 ptp4l[151.412]: port 1: INITIALIZING to LISTENING on INITIALIZE ptp4l[151.413]: config item /var/run/ptp4l.logMinDelayReqInterval is 0 ptp4l[151.413]: config item /var/run/ptp4l.logAnnounceInterval is 1 ptp4l[151.414]: config item /var/run/ptp4l.announceReceiptTimeout is 0 ptp4l[151.414]: config item /var/run/ptp4l.syncReceiptTimeout is 0 ptp4l[151.414]: config item /var/run/ptp4l.transportSpecific is 0 ptp4l[151.414]: config item /var/run/ptp4l.logSyncInterval is 0 ptp4l[151.414]: config item /var/run/ptp4l.logMinPdelayReqInterval is 0 ptp4l[151.415]: config item /var/run/ptp4l.neighborPropDelayThresh is 20000000 ptp4l[151.415]: config item /var/run/ptp4l.min_neighbor_prop_delay is -20000000 ptp4l[151.416]: config item (null).uds_address is '/var/run/ptp4l' ptp4l[151.416]: port 0: INITIALIZING to LISTENING on INITIALIZE ptp4l[151.418]: interface index 1 is up ptp4l[151.419]: interface index 2 is down ptp4l[151.419]: interface index 3 is down ptp4l[151.420]: interface index 4 is up ptp4l[151.420]: port 1: link up ptp4l[151.421]: interface index 5 is down ptp4l[152.319]: port 1: setting asCapable ptp4l[153.319]: port 1: new foreign master 1831bf.fffe.e0ee96-1 ptp4l[154.621]: port 0: setting asCapable ptp4l[157.320]: selected best master clock 1831bf.fffe.e0ee96 ptp4l[157.321]: foreign master not using PTP timescale ptp4l[157.322]: port 1: LISTENING to UNCALIBRATED on RS_SLAVE ptp4l[158.404]: port 1: delay timeout ptp4l[158.408]: delay filtered 236138 raw 236138 ptp4l[159.321]: master offset -317886227951 s0 freq +0 path delay 236138 ptp4l[160.101]: port 1: delay timeout ptp4l[160.104]: delay filtered 234415 raw 232693 ptp4l[160.321]: master offset -317886232397 s1 freq -4444 path delay 234415 ptp4l[160.884]: port 1: delay timeout ptp4l[161.321]: master offset -3311 s2 freq -7755 path delay 234415 ptp4l[161.322]: port 1: UNCALIBRATED to SLAVE on MASTER_CLOCK_SELECTED ptp4l[162.322]: master offset -1548 s2 freq -6985 path delay 234415 ptp4l[163.120]: port 1: delay timeout ptp4l[163.124]: delay filtered 232693 raw 231386 ptp4l[163.322]: master offset 38 s2 freq -5864 path delay 232693 ptp4l[163.936]: port 1: delay timeout ptp4l[163.939]: delay filtered 232039 raw 58862 ptp4l[164.322]: master offset -114 s2 freq -6004 path delay 232039 ptp4l[164.446]: port 1: delay timeout ptp4l[164.449]: delay filtered 231386 raw 230110 ptp4l[165.322]: master offset -681 s2 freq -6606 path delay 231386 ptp4l[166.322]: master offset -374 s2 freq -6503 path delay 231386 ptp4l[166.348]: port 1: delay timeout ptp4l[166.351]: delay filtered 231908 raw 232430 ptp4l[166.878]: port 1: delay timeout ptp4l[166.882]: delay filtered 232430 raw 233931 ptp4l[167.322]: master offset -2300 s2 freq -8541 path delay 232430 ptp4l[167.740]: port 1: delay timeout ptp4l[167.743]: delay filtered 232561 raw 232969 ptp4l[168.323]: master offset -260 s2 freq -7191 path delay 232561 ptp4l[168.480]: port 1: delay timeout ptp4l[168.484]: delay filtered 232693 raw 236010 ptp4l[169.323]: master offset -725 s2 freq -7734 path delay 232693 ptp4l[169.374]: port 1: delay timeout ptp4l[169.377]: delay filtered 232831 raw 233908 ptp4l[170.167]: port 1: delay timeout ptp4l[170.170]: delay filtered 232561 raw 228615 ptp4l[170.323]: master offset 958 s2 freq -6269 path delay 232561 ptp4l[171.323]: master offset 284 s2 freq -6655 path delay 232561 ptp4l[172.038]: port 1: delay timeout ptp4l[172.042]: delay filtered 232699 raw 233889 ptp4l[172.324]: master offset -768 s2 freq -7622 path delay 232699 ptp4l[172.358]: port 1: delay timeout ptp4l[172.361]: delay filtered 233429 raw 235046 ptp4l[173.324]: master offset -366 s2 freq -7450 path delay 233429 ptp4l[174.236]: port 1: delay timeout ptp4l[174.239]: delay filtered 233429 raw 229687 ptp4l[174.324]: master offset 830 s2 freq -6364 path delay 233429 ptp4l[174.780]: port 1: delay timeout ptp4l[174.783]: delay filtered 233550 raw 233211 ptp4l[175.324]: master offset -472 s2 freq -7417 path delay 233550 ptp4l[175.842]: port 1: delay timeout ptp4l[175.845]: delay filtered 233550 raw 231953 ptp4l[176.088]: port 1: delay timeout ptp4l[176.092]: delay filtered 233550 raw 234050 ptp4l[176.238]: port 1: delay timeout ptp4l[176.241]: delay filtered 233550 raw 231870
Testing on device side - (Local clock Synchronization)
The previous step allows the device to receive and make the HW timestamp available to the local clock source or application.
phyc2sys utility works in conjunction with the ptp4l utility to synchronize the local
system clock with the grand master clock source.
root@imx6ul-var-dart:~# phc2sys -s /dev/ptp0 -w -l 6 -q -m phc2sys[155.624]: Waiting for ptp4l... phc2sys[156.626]: Waiting for ptp4l... phc2sys[157.629]: Waiting for ptp4l... phc2sys[158.631]: Waiting for ptp4l... phc2sys[159.634]: Waiting for ptp4l... phc2sys[160.636]: Waiting for ptp4l... phc2sys[161.638]: Waiting for ptp4l... phc2sys[162.640]: phc offset 145614395359 s0 freq +0 delay 6000 phc2sys[163.641]: phc offset 145614395519 s1 freq +160 delay 6666 phc2sys[164.642]: phc offset -317 s2 freq -157 delay 6000 phc2sys[165.643]: phc offset -180 s2 freq -115 delay 6000 phc2sys[166.643]: phc offset -77 s2 freq -66 delay 6000 phc2sys[167.644]: phc offset -11 s2 freq -23 delay 6000 phc2sys[168.644]: phc offset 380 s2 freq +364 delay 6333 phc2sys[169.645]: phc offset -384 s2 freq -286 delay 6000 phc2sys[170.646]: phc offset 199 s2 freq +182 delay 6333 phc2sys[171.646]: phc offset -275 s2 freq -232 delay 6000 phc2sys[172.647]: phc offset -20 s2 freq -60 delay 6000 phc2sys[173.648]: phc offset 61 s2 freq +15 delay 6000 phc2sys[174.648]: phc offset 188 s2 freq +161 delay 6333 phc2sys[175.649]: phc offset 133 s2 freq +162 delay 6333 phc2sys[176.650]: phc offset -222 s2 freq -153 delay 6000 phc2sys[177.650]: phc offset -153 s2 freq -151 delay 6000 phc2sys[178.651]: phc offset 324 s2 freq +280 delay 6333 phc2sys[179.652]: phc offset -22 s2 freq +32 delay 6333 phc2sys[180.652]: phc offset 20 s2 freq +67 delay 6333 phc2sys[181.653]: phc offset -46 s2 freq +7 delay 6333 phc2sys[182.654]: phc offset -27 s2 freq +12 delay 6333 phc2sys[183.654]: phc offset -392 s2 freq -361 delay 6000 phc2sys[184.655]: phc offset 16 s2 freq -70 delay 6000 phc2sys[185.656]: phc offset 103 s2 freq +21 delay 6000 phc2sys[186.656]: phc offset 55 s2 freq +4 delay 6000 phc2sys[187.657]: phc offset 38 s2 freq +4 delay 6000 phc2sys[188.657]: phc offset 88 s2 freq +65 delay 6000 phc2sys[189.658]: phc offset -56 s2 freq -52 delay 6000 phc2sys[190.659]: phc offset 37 s2 freq +24 delay 6000 phc2sys[191.659]: phc offset 326 s2 freq +324 delay 6333 phc2sys[192.660]: phc offset -335 s2 freq -239 delay 6000 phc2sys[193.661]: phc offset 71 s2 freq +66 delay 6333 phc2sys[194.661]: phc offset 117 s2 freq +133 delay 6333 phc2sys[195.662]: phc offset -220 s2 freq -168 delay 6000 phc2sys[196.662]: phc offset -136 s2 freq -150 delay 6000 phc2sys[197.663]: phc offset 181 s2 freq +126 delay 6333 phc2sys[198.664]: phc offset 199 s2 freq +198 delay 6333 phc2sys[199.664]: phc offset -308 s2 freq -249 delay 6000 phc2sys[200.665]: phc offset 5 s2 freq -29 delay 6000 phc2sys[201.666]: phc offset 258 s2 freq +226 delay 6333 phc2sys[202.666]: phc offset 83 s2 freq +128 delay 6333 phc2sys[203.667]: phc offset 8 s2 freq +78 delay 6333 phc2sys[204.667]: phc offset -489 s2 freq -416 delay 6000 phc2sys[205.668]: phc offset 328 s2 freq +254 delay 6333 phc2sys[206.669]: phc offset -1 s2 freq +23 delay 6334 phc2sys[207.669]: phc offset -307 s2 freq -283 delay 6000 phc2sys[208.670]: phc offset -27 s2 freq -95 delay 6000 phc2sys[209.671]: phc offset 67 s2 freq -9 delay 6000 phc2sys[210.671]: phc offset 459 s2 freq +403 delay 6333 phc2sys[211.672]: phc offset -326 s2 freq -244 delay 6000 phc2sys[212.672]: phc offset -110 s2 freq -126 delay 6000 phc2sys[213.673]: phc offset 224 s2 freq +175 delay 6333 phc2sys[214.674]: phc offset -117 s2 freq -99 delay 6000 phc2sys[215.674]: phc offset -58 s2 freq -75 delay 6000 phc2sys[216.675]: phc offset 450 s2 freq +415 delay 6333 phc2sys[217.676]: phc offset 40 s2 freq +140 delay 6333 phc2sys[218.676]: phc offset -182 s2 freq -70 delay 6333 phc2sys[219.677]: phc offset -164 s2 freq -106 delay 6333 root@imx6ul-var-dart:~#
HW Events
After kernel up, run commands:
$ ptp4l -A -4 -H -m -i eth1 & $ echo 1 > /sys/class/ptp/ptp0/pps_enable