Ethernet Sample Application to send and receive packet with loopback

[keykur111]

#zephyr #S32K148EVB #ethernet #Enet_ip

I would like to use net_if ,ethernet APIs and create a application where i can send and receive net package in loopback manner.

I can see the driver apis in zephyr but cannot see much use of it in any sample application or not doing in loopback manner. I would like to design any of below sample application. the major gap for me is configuring loopback and receiving the package.

-enet

-net_if

i have tried using ETH_NET_DEVICE_INIT, ethernet_init(),net_context_sendto(),etc.

[jukkar]

Just use the socket API to send and receive the data, there is no Ethernet specific API for this. If you want to control the Ethernet header information, you can create a packet socket which allows you to construct L2 and L3 headers by yourself. There is a network sample https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/net/sockets/packet that shows how to use the packet socket. Not sure what you mean by loopback manner. If you want to use the loopback interface, then that does not have L2 so it is not an Ethernet based interface.

[keykur111]

Thank you for your suggestion

• I have tried to use https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/net/sockets/packet, but for my board s32k148_evb it is not building with below error.

/01_zephyrproject/zephyr/include/zephyr/device.h:96:41: error: '__device_dts_ord_DT_N_S_soc_S_ethernet_40079000_S_ethernet_P_phy_handle_IDX_0_PH_ORD' undeclared here (not in a function) 96 | #define DEVICE_NAME_GET(dev_id) _CONCAT(__device_, dev_id)

• terminal output:

build_err_pkt.txt

• i would like to know what is wrong with my build

1. devicetree config -i tried to play around with dts,dtsi,etc..
2. drivers are not available
3. prj.conf - any Kconfig to be enabled. - tried many things related to ethernet, ipv4 etc...
4. any code need to be updated.

[jukkar]

Just guessing here, but perhaps phy driver is not compiled in properly

[manuargue]

Hi @keykur111 . The S32K148EVB-Q176 needs to be used in combination with the daughter board ADTJA1101-RMII to access the Ethernet PHY. Please try adding --shield nxp_adtja1101 to west build to build with the Zephyr shield for the daughter board: https://docs.zephyrproject.org/latest/boards/shields/nxp_adtja1101/doc/index.html#programming

[manuargue]

You need to plug the ethernet cable to the board and to the partner (e.g. your host) so that the Ethernet PHY can detect the link.

That said, it's not very clear to me what you're trying to achieve. Loopback can happen in multiple places. Currently, neither the generic Ethernet PHY driver or the nxp,enet-mac driver support loopback in the PHY or the MAC, respectively. So unless you want to bypass the L2 Ethernet as it was mentioned above, that's not supported out of the box with these drivers.

[manuargue]

hi @keykur111 , did the information provided help? else please provide more details on your use-case and what you're trying to achieve to be able to help you better. Thanks

[keykur111]

hi @keykur111 , did the information provided help? else please provide more details on your use-case and what you're trying to achieve to be able to help you better. Thanks

thank you @manuargue . It really helped me to build the sample applications.
on the same hardware i have tried PHY loopback with other BareMetal software it works fine. but the similar PHY loopback i want to achieve using zephyr. it is fine if L2 lopback also possible.

[manuargue]

but the similar PHY loopback i want to achieve using zephyr

To enable the PHY loopback (internal, external or remote) you can use the phy Zephyr API from your application to write to the TJA1101 registers directly.

[keykur111]

Thank you @manuargue . i am able to bulid with all the help. I will be trying with actual host connected to ethernet and later i will check for loopback application.