Re: agl-minimal-image not booting with uboot if dtoverlay=pwm is added to config.txt

["Paulo Sherring" <pauloasherring@xxxxxxxxx>]

Hello Carles,

I was working with AGL + RPi4 for a while, so, maybe I can try to help
you out here.
RPi4 uses a GPU based bootloader that runs before u-boot.
So, the loading of the device tree is handled outside (and before) uboot.
As matter of fact, you could ditch uboot altogether

I am not sure how you created your dtb file, if it is only an overlay
or if it is a full-blown dtb (base bcm2711-rpi + your changes).

If you have an overlay, it would be a matter of editing config.txt
file with some
dtoverlay=<asd.dtb>
dtparam=<your params, if required>

if otherwise, you may want to copy to the boot partition and rename
your full-blown dtb to bcm2835-rpi-b.dtb, which gets picked by default
by the first stage loader.

You may want also to take a better look at the rpi4 documentation [1],
and maybe special attention to [2], [3].
[1] https://www.raspberrypi.com/documentation/
[2] https://www.raspberrypi.com/documentation/computers/configuration.html#part3.1
[3] https://www.raspberrypi.com/documentation/computers/config_txt.html

kind regards, Paulo.

On Thu, Jul 28, 2022 at 4:42 PM Carles Sole via
lists.automotivelinux.org
<Carles.SoleMendi=de.bosch.com@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello Jan-Simon,
>
> I was reviewing your reply once more and I managed to create a custom dtb called bcm2711-rpi-4-b+pwm.dtb. However I do not quite understand how do you tell u-boot to load your custom dtb instead of the original  bcm2711-rpi-4-b.dtb. Can this be done a "permanent" way or do I need to go into the u-boot environment and load the dtb there?
>
> Any hints on this would be very much appreciated.
>
> I also did not understand what did you mean by "app bits". I have managed to enable logging in u-boot itself as mentioned in my reply to Hiroyuki below. I am not sure it that helps.
>
> Thanks,
>
> Carles
>
> 


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