TMDSIDK437X: PRU-eth support

Felix Debus

Part Number: TMDSIDK437X
Other Parts Discussed in Thread: TMDSEVM437X

Tool/software:

Hi team,

I want to test the PRU-ETH connection with linux on the AM437x processor.

To do that I ordered a TMDSIDK437x board because I saw that there are 2 PRUETH ports available. I also flashed the newest version of the Linux SDK onto the SDK card.

Now I wanted to check the connection but I noticed that the PRU-ETH drivers are not loaded.

Are the PRU ETH drivers for linux loaded by default in the SDK or do I need to make some adaptions in the device tree for this board?

Best regards

Felix

9 months ago

0 Felix Debus 9 months ago

TI__Intellectual 1360 points

Hi team,

do you have any news for me?

Best regards

Felix

0 Daolin Qiu 9 months ago in reply to Felix Debus

TI__Mastermind 18615 points

Hi Felix,

Our PRU-ETH subject matter expert is out of office this week. Please kindly ping this thread if you don't hear any response by next week.

-Daolin

0 Nick Saulnier 9 months ago

TI__Guru** 108210 points

Hello Felix,

Apologies for the delayed responses here. What SDK are you using? SDK 8.2 was the last SDK where we supported PRU Ethernet for AM335x & AM437x, and then it was descoped on SDK 9.1 & SDK 9.3 (kernel 6.1).

We are bringing support for PRU Ethernet back on the upcoming SDK 11.x (currently scheduled for October). I can also point you to the CICD release now if you need it sooner, I would just need to work with the team to get you the latest version of the PRU Ethernet firmware that gets loaded into the PRU cores.

Regards,

Nick

0 Felix Debus 9 months ago in reply to Nick Saulnier

TI__Intellectual 1360 points

Hi Nick,

thank you for your answer.

I use the newest one and I have a SDK which was deliverd with the IDK Board.

Does the SDK 8.2 support then PRU-ETH on the IDK on port 0 or 1? Does the TMDSEVM437x also support PRU ETH on one of its ethernet ports?

Best regards

Felix

0 Felix Debus 9 months ago in reply to Felix Debus

TI__Intellectual 1360 points

Hi Nick,

I flashed today the version 8.2 and it works with the ICSS thanks!

During my tests with iperf/iperf3 I noticed that the max throughput was 29Mbit/s. Do you know how can I optimize this?

Best regards

Felix

0 Felix Debus 9 months ago in reply to Felix Debus

TI__Intellectual 1360 points

Hi Nick,

do you have an update for me?

I also want to add that the CPSW can send with 95Mbis/s by just 40% CPU load.

Do you know why both implementations are so different in its performance?

Best regards

Felix

0 Nick Saulnier 8 months ago in reply to Felix Debus

TI__Guru** 108210 points

Hello Felix,

Thank you for your patience here.

Summary from our verbal discussion

1) PRU Ethernet throughput dropped in SDK releases 7.3 and 8.2 (where the best performance was in SDK 6.3). This is a known issue: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1083609/am4378-pru-eth-performance

2) We were able to root cause the issue as per that previous thread. PRU Ethernet throughput should be back at SDK 6.3 levels in the upcoming AM437x SDK 11.1.

Updates since our discussion

The latest version of the Linux kernel drivers are here (version 8). There will be at least one more version (v9), not sure if there is a set timeframe for merging these commits into mainline: https://lore.kernel.org/all/20250610105721.3063503-1-parvathi@couthit.com/

I am still talking with the team to understand exactly what kind of throughput performance we can expect.

You can find some limited throughput tests attached to v8 of the Linux kernel patches (for convenience, linking here as well: https://gist.github.com/ParvathiPudi/5d84ad41bb8b6109504248598478e586 ). But that does not cover cases like different packet sizes.

Still working on finding PRU firmware binaries for you to play around with, but hopefully this is a good start.

Regards,

Nick

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TMDSIDK437X: PRU-eth support