gPTP Sample Application¶

Overview¶

The gPTP sample application for Zephyr will enable gPTP support, registers gPTP phase discontinuity callback, enable traffic class support (TX multi queues) and setup VLANs (if enabled). The net-shell is also enabled so that user can monitor gPTP functionality.

The source code for this sample application can be found at: samples/net/gptp.

Requirements¶

Networking with QEMU

Building and Running¶

A good way to run this sample is to run this gPTP application inside QEMU as described in Networking with QEMU or with embedded device like FRDM-K64F. Note that gPTP is only supported for boards that have ethernet port and which has support for collecting timestamps for sent and received ethernet frames.

Follow these steps to build the gPTP sample application:

# On Linux/macOS
cd $ZEPHYR_BASE/samples/net/gptp
mkdir build && cd build
# On Windows
cd %ZEPHYR_BASE%\samples\net\gptp
mkdir build & cd build
cmake -GNinja -DBOARD=<board to use> -DCONF_FILE=prj.conf ..
ninja

The net-shell command “net gptp” will print out general gPTP information. For port 1, the command “net gptp 1” will print detailed information about port 1 statistics etc. Note that executing the shell command could affect the timing of the sent or received gPTP packets and the grandmaster might mark the device as non AS capable and disable it.

Setting up Linux Host¶

If you need VLAN support in your network, then the samples/net/vlan/vlan-setup-linux.sh provides a script that can be executed on the Linux host. It creates two VLANs on the Linux host and creates routes to Zephyr.

The OpenAVNU repository at https://github.com/AVnu/OpenAvnu contains gPTP daemon that can be run in Linux host and which can act as a grandmaster for the IEEE 801.1AS network.

After downloading the source code, compile it like this in Linux:

mkdir build
cd build
cmake ..
make
cp daemons/gptp/gptp_cfg.ini build/daemons/gptp/
cd build/daemons/gptp

Edit the gptp_cfg.ini file and set the neighborPropDelayThresh to 10000 as the default value 800 is too low if you run the gPTP in FRDM-K64F.

Then execute the daemon with correct network interface and the configuration file.

sudo ./gptp enp0s25 -F gptp_cfg.ini

Note that here the example network interface enp0s25 is the name of the non-VLAN network interface that is connected to your Zephyr device.

If everything is configured correctly, you should see following kind of messages from gptp:

INFO     : GPTP [13:01:14:837] gPTP starting
INFO     : GPTP [13:01:14:838] priority1 = 248
INFO     : GPTP [13:01:14:838] announceReceiptTimeout: 3
INFO     : GPTP [13:01:14:838] syncReceiptTimeout: 3
INFO     : GPTP [13:01:14:838] LINKSPEED_100MB - PHY delay
                    TX: 1044 | RX: 2133
INFO     : GPTP [13:01:14:838] LINKSPEED_1G - PHY delay
                    TX: 184 | RX: 382
INFO     : GPTP [13:01:14:838] neighborPropDelayThresh: 10000
INFO     : GPTP [13:01:14:838] syncReceiptThreshold: 8
ERROR    : GPTP [13:01:14:838] Using clock device: /dev/ptp0
STATUS   : GPTP [13:01:14:838] Starting PDelay
STATUS   : GPTP [13:01:14:838] Link Speed: 1000000 kb/sec
STATUS   : GPTP [13:01:14:871] AsCapable: Enabled
STATUS   : GPTP [13:01:16:497] New Grandmaster "3C:97:0E:FF:FE:23:F2:32" (previous "00:00:00:00:00:00:00:00")
STATUS   : GPTP [13:01:16:497] Switching to Master

If Zephyr syncs properly with gptp daemon, then this is printed:

STATUS   : GPTP [13:01:25:965] AsCapable: Enabled

By default gPTP in Zephyr will not print any gPTP debug messages to console. One can enable debug prints by setting CONFIG_NET_DEBUG_GPTP in the config file.