[Buildroot] Nitrogen8M stuck at boot with master branch

[Gary Bisson <gary.bisson@boundarydevices.com>]

Hi,

On Thu, Dec 17, 2020 at 01:03:26AM +0000, Emil Velikov wrote:
> On Wed, 16 Dec 2020 at 13:11, Emil Velikov <emil.l.velikov@gmail.com> wrote:
> >
> > On Wed, 16 Dec 2020 at 13:10, Emil Velikov <emil.l.velikov@gmail.com> wrote:
> > >
> > > Greetings everyone,
> > >
> > > Recently I've started thinkering with a Nitrogen8M SBC - the regular
> > > one, not the Mini, Nano or SOM ones.
> > >
> > > Since this was my first experience with the board, initially I tried
> > > the vendor provided Ubuntu image [1], which was working OOTB.
> > >
> > > Booting a minimal buildroot (make nitrogen8m_defconfig && make) seems
> > > to be getting stuck as below. The full boot log attached.
> > >
> > Forgot the boot.log :-)
> >
> Upon a closer look, it appears that boot locks up during the first
> arm_smccc_smc().
> The one in busfreq_probe() for the vendor kernel or imx8m_ddrc_probe()
> for the upstream ones.
> 
> Wild guess is that the built lpddr4_pmu_train firmware has regressed
> or we're not using it properly.
> 
> As always, any hints will be appreciated.

We've seen people having issues with 5.4 kernels when their bootloader
was old. Please make sure to upgrade to latest U-Boot [1].

This is due to ATF changes NXP made which seemed to be needed for 5.4.

Regards,
Gary

[1] https://boundarydevices.com/how-to-upgrade-u-boot/