Hi Ilias, On Tue, 26 Oct 2021 at 08:06, Ilias Apalodimas <ilias.apalodi...@linaro.org> wrote: > > Hi Simon, > > > + > > [...] > > > +This is why `CONFIG_OF_SEPARATE` should always be used when building > > U-Boot. > > +The `CONFIG_OF_EMBED` option embeds the devicetree somewhere in the U-Boot > > ELF > > +image as rodata, meaning that it is hard to find it and it cannot increase > > in > > +size. > > + > > +When modifying the devicetree, the different cases to consider are as > > follows: > > + > > +- CONFIG_OF_SEPARATE > > + This is easy, described above. Just change, replace or rebuild the > > + devicetree so it suits your needs, then rerun binman or redo the `cat` > > + operation to join `u-boot-nodtb.bin` and the new `u-boot.dtb` > > + > > +- CONFIG_OF_EMBED > > + This is tricky, since the devicetree cannot easily be located. If the > > EFL > > + file is available, then the _dtb_dt_begin and __dtb_dt_end symbols can > > be > > + examined to find it. While it is possible to contract the file, it is > > not > > + possible to expand the file since that would involve re-linking > > + > > +- CONFIG_OF_BOARD > > + This is a board-specific situation, so needs to be considered on a > > + case-by-case base. The devicetree must be modified so that the correct > > + one is provided to U-Boot. How this is done depends entirely on the > > + implementation of this option for the board. It might require > > injecting the > > + changes into a different project somehow using tooling available > > there, or > > + it might involve merging an overlay file at runtime to obtain the > > desired > > + result. > > I thought this document was trying to describe the current situation in > U-Boot. If so, the current CONFIG_OF_BOARD usage is far from what we have > here.
Can you be more specific? What is the difference here? Also see the doc update later in the series, after OF_BOARD becomes a bool option. Regards, SImon
