On Mon, Aug 16, 2021 at 06:03:52AM +0000, Hongbo Wang wrote: > > I was going to suggest as an alternative to define a device tree overlay file with > > the changes in the CPU port assignment, instead of defining a wholly new DTS > > for the LS1028A reference design board. But I am pretty sure that it is not > > possible to specify a /delete-property/ inside a device tree overlay file, so that > > won't actually work. > > hi Vladimir, > > if don't specify "/delete-property/" in this dts file, the corresponding dtb will not work well, > so I add it to delete 'ethernet' property from mscc_felix_port4 explicitly. Judging by the reply, I am not actually sure you've understood what has been said. I said: There is an option to create a device tree overlay: https://www.kernel.org/doc/html/latest/devicetree/overlay-notes.html We use these for the riser cards on the LS1028A-QDS boards. https://source.codeaurora.org/external/qoriq/qoriq-components/linux/tree/arch/arm64/boot/dts/freescale/fsl-ls1028a-qds-13bb.dts?h=LSDK-20.12-V5.4 They are included as usual in a U-Boot ITB file: / { images { /* Base DTB */ ls1028aqds-dtb { description = "ls1028aqds-dtb"; data = /incbin/("arch/arm64/boot/dts/freescale/fsl-ls1028a-qds.dtb"); type = "flat_dt"; arch = "arm64"; os = "linux"; compression = "none"; load = <0x90000000>; hash@1 { algo = "crc32"; }; }; /* Overlay */ fdt@ls1028aqds-13bb { description = "ls1028aqds-13bb"; data = /incbin/("arch/arm64/boot/dts/freescale/fsl-ls1028a-qds-13bb.dtb"); type = "flat_dt"; arch = "arm64"; load = <0x90010000>; }; }; }; In U-Boot, you apply the overlay as following: tftp $kernel_addr_r boot.itb && bootm $kernel_addr_r#ls1028aqds#ls1028aqds-13bb It would have been nice to have a similar device tree overlay that changes the DSA master from eno2 to eno3, and for that overlay to be able to be applied (or not) from U-Boot. But it's _not_ possible, because you cannot put the /delete-property/ (that you need to have) in the .dtbo file. Or if you put it, it will not delete the property from the base dtb. That's all I said.
