Re: Systemd-boot not properly loading device tree, when loaded by U-boot (ARM64, tested on RK3399)

[Lennart Poettering <lennart@xxxxxxxxxxxxxx>]

On Fr, 17.09.21 19:25, Qu Wenruo (wqu@xxxxxxxx) wrote:

> Hi,
>
> I'm recently testing booting my RK3399 boards with the following boot
> sequence:
>
> U-boot -> systemd-boot (EFI payload) -> kernel
>
> Which provides much more flex than plain extlinux conf from U-boot.
> (More choice, easier to write config, runtime kernel change).
>
> So far "kernel" and "initramfs" key work fine.
>
> But I notice that "devicetree" key is not working properly.
>
> The Uboot fdt search path doesn't include "/dtbs" which is used by my
> distro, and my entry config specify the device-tree file like this:
>
> title        ManjaroARM boot from nvme
> linux        /Image
> devicetree    /dtbs/rockchip/rk3399-rockpro64.dtb
> initrd        /initramfs-linux.img
> options        console=ttyS2,1500000 root=/dev/arm_nvme/root rw loglevel=7
>
> Thus if systemd-boot doesn't load the correct device-tree, kernel will
> use the default fdt passed from Uboot, which is already out-of-date and
> can cause problems for the upstream kernel I used.
>
> Unfortunately, with above config, after booting the kernel, the fdt is
> the fallback one from Uboot, not loading the proper one specified by
> systemd-boot config.
>
> The proof I went is checking the opp table.
> I have replaced the "/dtbs/rockchip/rk3399-rockpro64.dtb" with a custom
> dtb which uses op1 tables.
> But the kernel only sees a very out-of-dated fdt, which some opp is even
> invalid.
>
> How could I continue debugging the missing link?
> Like what systemd-boot needs to load the device-tree? Or U-boot EFI
> environment lacks certain facility to support systemd-boot?

Did you see this:

https://github.com/systemd/systemd/pull/19417

(and maybe this: https://github.com/systemd/systemd/pull/20601)

maybe that addresses your issues?

Lennart

--
Lennart Poettering, Berlin