SPE: aon_echo : Permission Denied

Hello.
I followed the Jetson Sensor Processing Engine (SPE) Developer Guide (r36.3 Release) and flashed the SPE firmware successfully. Then to test the IVC App, I made the necessary changes/additions to the Linux_for_Tegra/source/hardware/nvidia/t23x/nv-public/nv-platform/tegra234-p3737-0000+p3701-xxxx-nv-common.dtsi file and recompiled it and flashed the whole device as instructed.


When i run $ sudo su -c ‘echo tegra > /sys/devices/platform/bus@0/bus@0:aon_echo/data_channel’, i am getting Permission denied .
Please guide me on this.

Thanks in advance!

Hello, arun.kumar.belamge:
Default BSP does not enable AON echo channel.
You can do the following:

  1. Re-build the OOT (Kernel Customization — NVIDIA Jetson Linux Developer Guide 1 documentation)
  2. In device side, install two modules.
    tegra234-aon.ko
    tegra-aon-ivc-echo.ko
  3. Update the kernel DTB as you’ve done.
  4. Re-build the SPE firmware in spe-freertos-bsp.tbz2
  5. Re-flash the device with above changes.

Then you can test AON IVC.
root@tegra-ubuntu:/sys/devices/platform/bus@0/bus@0:aon_echo# echo test >data_channel
root@tegra-ubuntu:/sys/devices/platform/bus@0/bus@0:aon_echo# cat data_channel
test
root@tegra-ubuntu:/sys/devices/platform/bus@0/bus@0:aon_echo# echo tegra >data_channel
root@tegra-ubuntu:/sys/devices/platform/bus@0/bus@0:aon_echo# cat data_channel
tegra

br
ChenJian

Hi ChenJian.

Thank you for the prompt reply.
I will test this and let you know.

Best Regards

Can you please elaborate the Step 2?
Where and how to install the two modules?

I have already re-built the kernel and got the two modules at : Linux_for_Tegra/source/kernel_out/nvidia-oot/drivers/platform/tegra/aon/

Hello, abelamge:
I don’t get your point.
Those two modules are in kernel_oot_modules_src.tbz2. Just follow the instructions in (Kernel Customization — NVIDIA Jetson Linux Developer Guide 1 documentation ) for OOT building.
It should be located at
kernel-source/nvidia-oot/drivers/platform/tegra/aon/tegra234-aon.ko
kernel-source/nvidia-oot/drivers/platform/tegra/aon/tegra-aon-ivc-echo.ko

br
ChenJian

Hello ChenJian.
This works, thank you for the support!
It would be good if installing the tegra234-aon.ko and tegra-aon-ivc-echo.ko modules is given as a step in the Jetson Sensor Processing Engine (SPE) Developer Guide.

BR

Hello, abelamge:
Thanks for pointing out that.
We have checked internally and module installation issue is fixed. And the two modules involved will be included in future release.

Just for your information.

br
ChenJian

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