Re: [PATCH 4/4] use builtin DT for nanopi-neo target

["MOESSBAUER, Felix" <felix.moessbauer@siemens.com>]

On Tue, 2023-08-08 at 10:48 +0200, Jan Kiszka wrote:
> On 01.08.23 11:37, Felix Moessbauer wrote:
> > The upstream kernel still misses the __symbol__ information in the
> > device tree. By that, overlays cannot be applied (DT was compiled
> > without -@). However, all u-boot internal device trees are compiled
> > with
> > symbol information. By that, just use the one from u-boot.
> > Note, that the mmclbk entry changed in this device tree (mmclbk2
> > instead of mmclbk0). This change is reflected in the wks file. An
> > alternative option would be to use --use-uuid.
> > 
> 
> I assume you actually booted with that modification, right? Did you
> check if there are no other differences between the two DTs? They can
> be
> subtle as U-Boot is not yet consistently syncing in the kernel DTs
> for
> all boards.

I booted the board with an MTDA image [1] which uses a lot of the
peripherals of that board. However, I did not do a 1:1 comparison of
the device tree from u-boot and the kernel.

The idea to use the DT from u-boot is based on

1. A kernel developer proposed this in [2]
2. It showcases the added (but now reverted) builtin_dt=yes support

In addition, the kernel DT from the stock debian kernel currently
cannot be used, as this does not support overlays (not compiled with
symbol information). Back then, it was unclear if the corresponding
kernel patch to compile with -@ will be accepted and by that this was
the only feasible solution. Now, the patch from [2] got accepted, but
there is still no release of the bookworm-backports kernel that
includes it.

[1] https://github.com/siemens/mtda
[2] https://www.spinics.net/lists/devicetree/msg622846.html

Best regards,
Felix

> 
> Jan
> 
> > Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
> > ---
> >  meta-isar/scripts/lib/wic/canned-wks/nanopi-neo.wks.in | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/meta-isar/scripts/lib/wic/canned-wks/nanopi-neo.wks.in
> > b/meta-isar/scripts/lib/wic/canned-wks/nanopi-neo.wks.in
> > index de1c92c4..af5b6f08 100644
> > --- a/meta-isar/scripts/lib/wic/canned-wks/nanopi-neo.wks.in
> > +++ b/meta-isar/scripts/lib/wic/canned-wks/nanopi-neo.wks.in
> > @@ -1,10 +1,10 @@
> >  #
> > -# Copyright (c) Siemens AG, 2018
> > +# Copyright (c) Siemens AG, 2018-2023
> >  #
> >  # SPDX-License-Identifier: MIT
> >  
> >  part u-boot --source rawcopy --sourceparams "file=/usr/lib/u-
> > boot/nanopi_neo/u-boot-sunxi-with-spl.bin" --no-table --align 8
> >  
> > -part / --source rootfs-u-boot --ondisk mmcblk0 --fstype ext4 --
> > mkfs-extraopts "-T default" --label platform --align 1024 --active
> > +part / --source rootfs-u-boot --ondisk mmcblk2 --fstype ext4 --
> > mkfs-extraopts "-T default" --sourceparams "builtin_dt=yes" --label
> > platform --align 1024 --active
> >  
> >  bootloader --append "rw rootwait"
>