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TDA4VM: "echo: write error" when trying to change remoteproc state

Part Number: TDA4VM


Hi,

Looking at the forums, I've found a few people that use the following commands to reflash the remote cores:

echo stop > /sys/class/remoteproc/remoteproc0/state
echo start > /sys/class/remoteproc/remoteproc0/state

However, when I try, I get the following:

-sh: echo: write error: Invalid argument

And stdout on the serial port outputs this:

[51251.322886] remoteproc remoteproc0: stop not supported for this rproc, use detach

Is there a guide on how to properly use remoteproc in Arago, and what are the requirements?

Also, is there a list of what remoteprocX is what core? I can kind of deduce it with

cat /sys/class/remoteproc/remoteprocX/name

But it can also be cryptic (e.g. 4d80800000.dsp for C6_1, 4d81800000.dsp fpr C6_2)

Thank you,

Fred

  • echo stop > /sys/class/remoteproc/remoteproc0/state
    echo start > /sys/class/remoteproc/remoteproc0/state

    Dynamically. Switching on/off remoteproc is NOT supported. 

    But it can also be cryptic (e.g. 4d80800000.dsp for C6_1, 4d81800000.dsp fpr C6_2)

    This is the way naming is done in Device tree. You can refer Device tree to get the mapping.

    - Keerthy

  • Hi Fred,

    The 'stop' and 'start' commands are primarily to be used with 'remoteproc' mode (Linux kernel has booted the processors). The error you are getting is because the remote processors are booted early in U-Boot or SPL, and are in 'IPC-only' mode. The remote processors cannot be stopped and re-started when they are booted in IPC-only mode, and that is the error you are getting.

    The dynamic switching on/off in remoteproc mode will be supported in a future SDK release. 

    regards

    Suman

  • Thank you both for the replies, they answer perfectly.