Re: Issue found when porting to new device.

On Mon, Aug 3, 2026 at 8:52 PM Fabio Estevam <[email protected]> wrote:
>
> Hi Vicente,
>
> [Copying the U-Boot Odroid GO2 maintainers]
>
> On Sun, Aug 2, 2026 at 1:35 AM Vicente Bergas <[email protected]> wrote:
> >
> > Hi,
> > i am porting u-boot to a new device:
> > https://handhelds.wiki/R36S_Handheld_Wiki
> >
> > Given the similarity with ODROID_GO2, i've based my efforts on it and
> > all goes fine up to the very last step: jumping from u-boot to linux.
> >
> > In the file arch/arm/cpu/armv8/transition.S there is a call to
> > armv8_switch_to_el2_m which is supposed to jump into linux, but it
> > doesn't.
> >
> > I've added some debug prints around it (see patch below) and it prints
> > the first message:
> > "before switch from EL3 to EL2"
> > but it does not print either of the messages after.
> >
> > As another test, i've tried to replace
> > armv8_switch_to_el2_m x4, x5, x6
> > to
> > br x4
> > and then it indeed switches to linux, but then linux crashes, prints a
> > trace and reboots, that is, it doesn't like running from EL3.
> >
> > Please, can somebody help here?
>
> Are you using a recent ARM Trusted Firmware?

Hi Fabio,
the version of ATF is the latest one: 2.15.

Thanks for your attempt for helping, but i already found the issue.
A few configuration options were accidentally dropped : FIT,
SPL_LOAD_FIT and SPL_ATF.
Now it is booting linux correctly and i switched tasks to port linux.

There could still be an issue with the macro armv8_switch_to_el2_m.
The current configuration boots linux through another code path.

Regards,
  Vicente.