On 2023/5/2 21:24, Heinrich Schuchardt wrote:
On 5/2/23 15:11, Andreas Schwab wrote:
On Mai 02 2023, Matthias Brugger wrote:
I'm not sure I get your point. The devicetree will be passed to the kernel via a pointer in a register, the kernel does not need to load the devicetree into memory, it will use the one passed by U-Boot.
But U-Boot needs to load it, and the kernel is the authority in providing it.
To make it a bit clearer:
Several U-Boot boot methods use the value of environment variable $fdtfile to load a device-tree from file. The same holds true for the boot.scr file created by Debian's flash-kernel package.
A good solution would be to read the EEPROM to determine the exact board version, to set $fdtfile accordingly and update U-Boots control dtb as needed.
The patcheset have implemented the reading of PCB versions from EEPROM and the configuration of gmac device tree nodes according to different PCB versions, which can achieve a bin file compatible with both versions 1.2A and 1.3B.
The patcheset link: https://patchwork.ozlabs.org/project/uboot/cover/20230428022515.29393-1-yanh...
Best regards
Heinrich