AM4378: Support Status of AM4378 SoC

I have an additional question. In the release notes for the latest release [2], it is noted that
  Generic PRU-ICSS Ethernet is descoped in 09.03.xx release.
What does this actually mean?

Kind regards, Daniel

[2] software-dl.ti.com/.../Release_Specific_Release_Notes.html

Hello Daniel,

You are asking at the right time! We are almost ready to release AM437x SDK 11.1/11.2 (not sure if we have decided on which name to give it). The official SDK release is coming out in mid to late November. You can see the current kernel 6.12 code on ti-linux-kernel. I see ti-rt-linux-6.12.y-arm32-cicd, and I suspect that the non-RT Linux kernel uses the same branch as "regular" Linux, ti-linux-6.12.y-cicd
https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/refs/heads

100Mbit PRU Ethernet on AM437x was supported until SDK 8.2, and then we had to drop support on SDK 9.1 & SDK 9.3 (i.e., the kernel drivers were not ported to kernel 6.1, and nothing was tested with kernel 6.1). However, we are bringing back support for PRU Ethernet on AM437x in SDK 11.x.

Regards,

Nick

One thing to note about RT Linux on 32 bit processors: support for RT Linux on 64 bit processors has been upstreamed, but the wider Linux community seems to be deprecating support for RT Linux on 32 bit processors. TI is not able to shoulder RT Linux support on 32 bit processors without the rest of the community also contributing. Speaking as an individual (and NOT as a representative of TI), I suspect that we will probably follow the community lead and deprecate RT Linux support on AM437x at some point. I am not sure if that will be this release, or a future release. I can ask around for more information if needed.

Regards,

Nick

Hello Nick,
Thanks for your answers. It would indeed be useful to know if the next release does support RT Linux because we depend on it and cannot use non-RT.
If the (official) decision is made to drop support for RT Linux, we would like to know as soon as possible so that we can plan accordingly.
Kind regards, Daniel

Hello Daniel,

I will ask around and get back to you. If I have not replied by Thursday or Friday, please ping the thread.

Regards,

Nick

Hello Nick Saulnier 

Gentle ping.

Kind regards, Daniel

Hello Daniel,

Before I type anything else: This is a nuanced discussion, and a lot of people have a lot of strong opinions. I am going to summarize some conversations that I was not a part of. I might get something wrong (or say something that was correct at some point in time, but is incorrect now, or in the future). So future readers, please be patient with me :P 

What is the current status of 32 bit RT Linux in general? 

RT Linux for 64 bit processors got merged into mainline Linux for Linux kernel 6.12. After that, at least earlier in 2025, it sounded like a lot of Linux community resources pivoted away from maintaining RT Linux patches for 32 bit Linux separate from mainline Linux, and towards addressing other parts of the kernel.

My understanding is that people who maintain 32 bit RT Linux were looking for information on whether a lot of people actually still need RT Linux support on 32 bit devices or not. As far as I am aware, there was not a clear community decision on "yes, this is something that many groups will continue investing in", or "no, it looks like not enough people care about this to keep maintaining it".

There was a development branch for 32 bit RT kernel 6.12 on git.kernel.org in summer 2025, but no stable repository. There is now both a development and stable branch. Further reading at https://wiki.linuxfoundation.org/realtime/preempt_rt_versions . I am not familiar with whether testing and validation on linux-rt-devel branches is different from testing & validation on linux-stable-rt branches, or whether testing & validation for kernel 6.12 was any different than earlier kernel versions.

Because of uncertainties earlier this year around whether the RT patches would even exist in the future, whether enough people would contribute to keep the project going, and how rigorously the patches would be tested compared to older releases, the TI software team is NOT planning to release an official RT Linux SDK release for AM335x & AM437x on Linux kernel 6.12.

What is the ti-rt-linux-6.12.y-arm32 branch? 

ti-rt-linux-6.12.y-arm32 is the RT patches from the RT Linux development branch applied on top of the ti-linux-6.12.y branch. I do not know if the RT patches on the arm32 branch have been updated from when the branch was created over the summertime. I do not think we have done a diff between the RT patches in the TI arm32 branch and the latest RT Linux stable branch.

The arm32 branch was created to help support mainline development on the 32 bit RT Linux kernel. But because of the above uncertainties, we cannot guarantee that it is as well tested as previous RT Linux SDKs. We can tell you that our TI processor tests run fine, but I do not believe that branch has been truly stressed with a bunch of edge case scenarios. If something goes wrong with the RT patches, the TI apps team will be unable to support questions to debug and fix.

What about future software releases? 

We are not making any decisions about 2026's software releases until we see where the community goes. If Linux as a whole does decide to invest in 32 bit RT Linux on kernel 6.18 or whatever the next LTS kernel release is, then I imagine we would release another official RT Linux release. But I cannot make any promises right now.

Regards,

Nick