[systemd-devel] Systemd-boot not properly loading device tree, when loaded by U-boot (ARM64, tested on RK3399)

[Qu Wenruo]

On 2021/9/17 19:45, Lennart Poettering wrote:
> On Fr, 17.09.21 19:25, Qu Wenruo (wqu at suse.com) 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 use the default fdt passed from Uboot, which is already out-of-date and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)

Awesome! Let me try these PRs and report back!

Thanks for the super-fast mention!
Qu

> 
> maybe that addresses your issues?
> 
> Lennart
> 
> --
> Lennart Poettering, Berlin
>