I am using the Apalis-IMX8 with torizonOS kernel 6.6.94-7.3.0-g5a62539de8f9 to develop a measurement system. I am trying to use the M4 cores and ideally I would like to use them via remoteproc (I have done this successfully on the verdin-imx8mm and on the var-som-mx8 from variscite). When I try to access the cores on the apalis, I see no available cores via remoteproc
ls /sys/class/remoteproc/
returns empty. I also cannot find an available devicetree overlay to potentially activate and when looking at this page:
It seems like it is not yet supported? Is this page up-to-date?
What steps should I take to use the M4 cores and the remoteproc driver?
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Hello! Thank you for your detailed question.
You are correct in your observation. According to the latest RemoteProc documentation for Toradex devices, RemoteProc support for the Apalis iMX8 (including device tree overlays to enable the M4 cores via remoteproc) is currently not available. The documentation states that the Apalis iMX8 HMP overlay (required to expose the M4 cores to the remoteproc framework) is marked as “Coming soon” and has not yet been released for the current kernel/BSP versions you are using (Reference).
What does this mean?
At this time, neither the /sys/class/remoteproc/ entries nor a pre-built overlay to enable them exist for the Apalis iMX8 on Torizon OS 6.
The page you referenced is up-to-date and reflects the current status for Apalis iMX8: no official remoteproc support is available as of now.
Alternatives you can consider:
Cortex-M4 Firmware Loading via U-Boot
You can load and run M4 firmware by using U-Boot shell commands, as described in the Toradex Cortex-M documentation: How to use Cortex-M on Apalis iMX8
This approach does not provide runtime control via remoteproc but does allow you to run your code on the M4 cores.
Custom Device Tree Overlay
If you are experienced with device tree development, you could attempt to develop your own overlays for M4 remoteproc support. This approach requires significant effort and validation, and at this point, reference overlays or documentation for the exact required changes are not publicly available.
Summary
RemoteProc is not yet supported for Apalis iMX8.
Please use the U-Boot loading method for now for M4 firmware.
Unfortunately, we don’t have an overlay to enable HMP on Apalis iMX8 ready for now, but R&D is working on this as we speak, so in the next few weeks, it should be available.
Would there be any possibility to have maybe some kind of 1-on-1 meeting with someone that could help us get started with implementing it ourselves or to look at temporary alternatives? It’s in the context of a spin-off where we will be needing multiple modules (specifically ones with two real-time cores like the Apalis IMX8).
I did ask on the NXP forums, but there they cannot offer support since it’s not one of their modules.
