PROCESSOR-SDK-AM64X: Log from R5 to Linux on A53

Hello Philip,

When you say "logs", are you looking for a text file where diagnostic output can be saved? Or are you looking specifically for output that is routed to a UART port?

Accessing the trace log from Linux

You can access the trace log for a remote core (i.e., non-Linux core) from /sys/kernel/debug/remoteproc/remoteprocX/trace0. Like this:

// let's see which remoteprocX is associated with which core
// this can change each boot, so make sure to check "name" each time
root@am64xx-evm:~# head /sys/class/remoteproc/remoteproc*/name
==> /sys/class/remoteproc/remoteproc0/name <==
78000000.r5f

==> /sys/class/remoteproc/remoteproc1/name <==
78200000.r5f

==> /sys/class/remoteproc/remoteproc10/name <==
...
==> /sys/class/remoteproc/remoteproc9/name <==
30034000.pru

// let's check the trace logs for R5F0_0
// I expect to see the IPC RPMsg Echo demo
root@am64xx-evm:~# cat /sys/kernel/debug/remoteproc/remoteproc0/trace0
[r5f0-0]     0.000431s : [IPC RPMSG ECHO] Jul  8 2024 10:25:09
[r5f0-0]     0.105724s : [IPC RPMSG ECHO] Remote Core waiting for messages at end point 13 ... !!!
[r5f0-0]     0.105746s : [IPC RPMSG ECHO] Remote Core waiting for messages at end point 14 ... !!!
[r5f0-0]     0.296727s : [IPC RPMSG ECHO] Message exchange started with RTOS cores !!!
[r5f0-0]     5.045893s : [IPC RPMSG ECHO] All echoed messages received by main core from 4 remote cores !!!
[r5f0-0]     5.045908s : [IPC RPMSG ECHO] Messages sent to each core = 100000
[r5f0-0]     5.045919s : [IPC RPMSG ECHO] Number of remote cores = 4
[r5f0-0]     5.045930s : [IPC RPMSG ECHO] Total execution time = 4749153 usecs
[r5f0-0]     5.045945s : [IPC RPMSG ECHO] One way message latency = 5936 nsec

You can find more information about enabling the memory log in the AM64x Academy:
Multicore > Application Development on Remote Cores > Add Linux IPC to the remote core project
https://dev.ti.com/tirex/explore/node?node=A__Ac4gvmV7H7iX5x.qB.hWZw__AM64-ACADEMY__WI1KRXP__LATEST

You can find more information about changing the size of the trace log in the AM64x Academy:
Multicore > Application Development on Remote Cores > Adding an empty resource table
https://dev.ti.com/tirex/explore/node?node=A__AbHsVQIi8pUVEQOLKmXydQ__AM64-ACADEMY__WI1KRXP__LATEST

Regards,

Nick

Hi Nick, 

sorry for my late response, we had some other issues that needed attention. I looked into the remoteproc trace log and it does look good to check if there were any issue during the initialization of the core. For this use case it will definetly help debugging.

For the case where I want to continously want to log something it does not work since there seems to be no good way to handle the ringbuffer nature of the trace0 file. On the AM64X EVM we write those to a UART, but this is no option for debugging production devices

We will propably look into writing logs via RpMsg from the R5 to Linux side, since we already use this in our application and could be implemented with not much effort.

Thank you and kind regards
Philip