[U-Boot-Users] using a flat device tree to drive u-boot config

Jon Smirl
2008-08-03T12:57:55Z

On 8/3/08, Wolfgang Denk <wd@denx.de> wrote:
> In message <9e4733910808021858i766307b1q45b5bace59996d03@mail.gmail.com> you wrote:
> >
> > > What about creating a tool that parses a device tree and creates (or
> > > updates) the board header file? This will retain compatibility with
> > > other platforms, clean up the existing header files (they won't need
> > > to contain as much information), and reduce the amount of changes to
> > > U-Boot itself.
> >
> > That's a good idea. I have used variation on this concept in the past
> > and they have worked out well.
>
>
> A much more powerful concept is to have U-Boot read and interpret the
> DT dynamically - only then can you use the same U-Boot binary image
> on different board configurations, which is an important feature for
> many board vendors.

I don't disagree with this but it is a lot more work.

>
> > A perfect tool would take a fully populated DTS file and use it to
> > dynamically generate all of the needed header files to build uboot.
> > More info would need to be added to the DTS file like DRAM timings,
> > etc. But a DTS file is good place to track all of that info. The
> > generated uboot image could contain a copy of the DTB and feed it to
> > Linux. Allow the user to override the embedded DTB if necessary.
>
>
> No, no, no. The DTB *must not* be included with the U-Boot image. It
> shall always be kept separate so we canupdate it independently -
> otherwise you lose a lot of advantages.

A DTB is only about 8K. I was thinking that a user supplied one would
override the one contained inside uboot.

>
> Best regards,
>
> Wolfgang Denk
>
>
> --
> DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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>

--
Jon Smirl
jonsmirl at gmail.com