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

[Jon Smirl]

On 8/3/08, Wolfgang Denk <wd at denx.de> wrote:
> In message <9e4733910808021858i766307b1q45b5bace59996d03 at 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
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>


-- 
Jon Smirl
jonsmirl at gmail.com