AM6442: IPC communication between Linux and SBL booted R5 application

Alexander Wahl

Prodigy 30 points

Part Number: AM6442

Tool/software:

Hallo TI,

I have a dual boot of linux on the A53 cores and a bare metal application on an R5 core running.

Both, Linux and the bare metal app are booted from the sbl.

Now i want to set up IPC communication. As far as i understood the documentation of the remoteproc and rpmsg linux drivers, these can only be used when booting the R5 from remoteproc in the linux kernel. I came to that conclusion because of the following sentence in the docs found at https://software-dl.ti.com/processor-sdk-linux/esd/docs/08_00_00_21/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/RemoteProc.html :

"The pru_rproc module also parses the firmware binaries looking for a section named .resource_table
This .resource_table section of the firmware specifies the system resources that the PRUs will need during their program execution"

The problem that i am facing right now is that i don't want the remoteproc driver to load any binaries in the r5 cores because my application is allready running.

So my question is, how can i use the rpmsg driver without the binary load of the remoteproc driver?

Best regards

Alex

10 months ago

0 Nick Saulnier 10 months ago

TI__Guru** 103890 points

Hello Alex,

Fixing issues before you run into them:

I am going to point you to one specific page that answers your current question, but please keep in mind that the AM64x academy's Multicore module has a bunch of additional information that you should also read through (e.g., how to ensure that you aren't creating any resource conflicts around memory allocations, or peripheral allocation? How to do certain kinds of IPC?). I would suggest reading through the other pages in the Multicore academy module as well.

I'm the guy who wrote the multicore academy, so feel free to reply back with questions or feedback.

onto your actual question: Can you use RPMsg IPC with a remote core that was NOT booted by Linux?

Yes you can. Just keep in mind that if Linux didn't boot the core, Linux will not be allowed to shut the core down during runtime (if that is a feature you care about). As long as you have that resource table, Linux will "attach" to the currently running core, and set up the RPMsg infrastructure when it attaches.

For more information, refer to:

Supported core initialization methods:
https://dev.ti.com/tirex/explore/node?node=A__Ab5AogqjWTRWB1yUfHHjTw__AM64-ACADEMY__WI1KRXP__LATEST

How to make sure your R5F application can be run alongside Linux:
https://dev.ti.com/tirex/explore/node?node=A__AfSHr0vWbFdGCnmoPeMXzg__AM64-ACADEMY__WI1KRXP__LATEST

(even if Linux is not the one initializing the remote core, you still need that resource table, and you still need to keep all those factors in mind)

Information about IPC:
https://dev.ti.com/tirex/explore/node?node=A__ASn.0Gvx.CK7j7a0EWKc.w__AM64-ACADEMY__WI1KRXP__LATEST

Regards,

Nick

Processors

Processors forum

AM6442: IPC communication between Linux and SBL booted R5 application