[U-Boot-Users] RFA & Update: Using libfdt in u-boot for fdt command

Jerry Van Baren
2007-03-02T01:17:15Z

Mark A. Greer wrote:
> On Thu, Mar 01, 2007 at 09:01:24AM -0500, Jerry Van Baren wrote:
>> Hi all,
>>
>> This is a Request for Advice.
>
> Hi Jerry.
>
> One minor thing. I'd just want to remind you that we shouldn't stray
> too far from the OF interface. The bootwrapper code sits on top of
> either the FDT access interface or the true OF DT access interface.
> The closer we keep the two, the cleaner & easier the we can keep
> the bootwrapper code.
>
> Mark

Hi Mark,

Understood, but that isn't really my battle. David Gibson created the
libfdt interface so any linux/bootwrapper changes are really his battle.
I'm working in u-boot land so linux/bootwrapper aren't in my problem
domain - using libfdt in u-boot doesn't affect the bootwrapper code.
Having said that, I'm hoping for shared code synergy, which would
require the linux kernel to adopt libfdt as a replacement for
flatdevtree.[ch]. David has also talked about using libfdt in the dtc
suite, so there is potentially a three way synergy.

The flattened device tree which is passed from u-boot to linux is
unchanged*, so the interface is the same at that level (to state the
obvious).

David's libfdt is a potential replacement for flatdevtree.c. I have
pursued using libfdt rather than flatdevtree (in u-boot) because the
interface is much cleaner (IMHO, and, I'm sure, IDHO). Of course "much
cleaner" is the fancy way of saying "not compatible." :-/ On the other
hand, I looked at arch/powerpc/boot/of.c, ops.h, and flatdevtree_misc.c.
It looks like it would be relatively easy to redo flatdevtree_misc.c
to glue to libfdt instead of flatdevtree.c (he says blithely).

* ...other than a backwards compatible version 16 -> 17 upgrade.

Best regards,
gvb