Am 13.10.2017 um 14:02 schrieb Frank Kunz: > Am Freitag, 13. Oktober 2017, 12:10:47 CEST schrieb Andreas Färber: >> Am 13.10.2017 um 11:22 schrieb Alexander Graf: >>> On 13.10.17 11:17, Frank Kunz wrote: >>>> I'm doing some test with EFI boot on an olinuxino board here: https:// >>>> build.opensuse.org/package/show/home:frank_kunz:branches:openSUSE:Factory >>>> :ARM/ JeOS-olinuxinolime >>>> >>>> The image works and the kernel has a device-tree visible under >>>> /proc/device- tree. With non EFI configurations the device-tree is >>>> loaded by uboot from the boot partition dtb directory and is then passed >>>> to the kernel by boot command. For EFI there is no dtb directory. Also I >>>> haven't found a *.dtb file on the filesystem anywhere. >>>> >>>> How does the kernel get the device-tree in EFI boot mode? >>> >>> It gets it from either a device tree that gets loaded from /boot/dtb or >>> if none is found from the built-in device tree that U-Boot contains. > > I successfully tried that by compiling a dtb file out of the upstream kernel > tree and copied it to the target board. U-boot then u-boot tries to load the > file from the first partition, which is the EFI partition. So then the > correct > path on Linux is then /boot/efi/dtb. > >>> >>>> The background is that some hardware specific configurations need to be >>>> done per use case in the device-tree. E.g. adding a battery or a touch >>>> screen. Without the device-tree settings the kernel will not probe the >>>> devices. Enabling that on u-boot boot mode can be done by either >>>> modifying the device-tree file or create overlays and load them by >>>> u-boot script with "fdt apply" command. How can this be configured in >>>> EFI mode? >>> >>> There are a couple of approaches. I think by now you can add dt overlays >>> on demand even after the kernel is loaded, so you could just have a >>> systemd service adding them for you. >> >> Please provide proof of such a feature - I don't believe it's in 4.13, >> and I haven't noticed it in 4.14-rc yet. Patchsets have been around for >> a long time... >> >> Depending on what overlay operation is desired, fdt apply could just >> operate on $fdtcontroladdr for the internal tree today. > > So far the only some u-boot configurations have the OF_LIBFDT_OVERLAY > configuration set. Without that the "fdt apply" command is not supported. > Also the distroboot environment is not supporting "fdt apply" yet. I think > with that, for the moment, supporting fdt overlays would be then a opensuse > specific configuration in boot.scr. That is then similar as raspibian and > armbian are doing it. They read a *Env.txt file which contains a list of > overlay file names.
Both issues - dtb on the wrong partition and lack of fdt apply - indicate that you're not using an openSUSE-built U-Boot. Please re-test. Regards, Andreas -- SUSE Linux GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg) -- To unsubscribe, e-mail: [email protected] To contact the owner, e-mail: [email protected]
