PROCESSOR-SDK-AM64X: R5F start and stop

Prashant Mhetar

Part Number: PROCESSOR-SDK-AM64X
Other Parts Discussed in Thread: PROCESSOR-SDK-AM65X

Hi Team,

To start and stop R5F we use below sysfs interface

echo stop > /sys/class/remoteproc/remoteproc18/state
echo start > /sys/class/remoteproc/remoteproc18/state

The communication between A53 and R5F cores is through RPMessage. Due to graceful stop we observed multiple rpmessage specific errors like:

_rpmsg_char_destroy_eptdev: could not destroy endpt 3
FAILED: Can't read from rpmsg endpt device.

How to start/stop R5F so that all RPmessage IPCs are removed?

Is there way at R5F side (Ti RTOS) to know start/stop signal received from A53?

Thanks,

Prashant

over 3 years ago

0 Kallikuppa Sreenivasa over 3 years ago

TI__Guru**** 188699 points

Hello Prashanth,

Thank you for the query.

Please expect a delay in response due to the upcoming US holiday.

Regards,

Sreenivasa

0 Nick Saulnier over 3 years ago

TI__Guru** 100660 points

Hello Prashant,

Please note that AM64x does NOT yet support graceful shutdown of remote cores from Linux as of Processor SDK 8.2. Reference the note at

https://software-dl.ti.com/processor-sdk-linux/esd/AM64X/08_02_00_17/exports/docs/linux/Foundational_Components_IPC64x.html#booting-remote-cores-from-linux-console-user-space

For now, we suggest rebooting the board if you want to load a new firmware into an R5F core.

Regards,

Nick

0 Prashant Mhetar over 3 years ago in reply to Nick Saulnier

Prodigy 40 points

Thank you Nick for quick reply.

We are using start/stop using sysfs interface for R5F cores. I would like to know:

Is there way at R5F side (Ti RTOS) to know start/stop signal received from A53?

Regards,

Prashant

0 Nick Saulnier over 3 years ago in reply to Prashant Mhetar

TI__Guru** 100660 points

Prashant,

To clarify: sending "stop" to an R5F from the Linux core is NOT supported as of Processor SDK 8.2. Sometimes the core will stop, but it will be in an unknown state. Sometimes the core will stop, but lock up the processor.

For more information on viewing the R5F output log from Linux, see my response here: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1100396/tmds64gpevm-how-to-debug-an-r5f-application-with-ipc-to-linux/4086425#4086425

Regards,

Nick

0 Prashant Mhetar over 3 years ago in reply to Nick Saulnier

Prodigy 40 points

Thank you Nick.

Do PROCESSOR-SDK-AM65X supports the start/stop to an R5F from the Linux core?

Also for PROCESSOR-SDK-AM65X , Is there way at R5F side (Ti RTOS) to know start/stop signal received from A53?

Thanks,

Prashant

0 Nick Saulnier over 3 years ago in reply to Prashant Mhetar

TI__Guru** 100660 points

Hello Prashant,

I believe that recent AM65x SDKs do support graceful shutdown of remote cores. However, I have not run tests myself at this point in time.

Note that AM64x and AM65x are different processors, running different software. For example, TI supports FreeRTOS on AM64x R5F cores, while we support TI RTOS on AM65x R5F cores.

Please tell us a bit more about what you are trying to do. Is there a particular reason you want the R5F firmware to be aware of whether if it has received a shutdown command?

From the remote core side, you would know that the the "start" command occurred because your code is running from the software entry point (i.e., because your code started running from the beginning).

Regards,

Nick

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PROCESSOR-SDK-AM64X: R5F start and stop