[U-Boot-Users] builtin OF tree dtb gone

Grant Likely grant.likely at secretlab.ca
Sun Dec 17 16:10:42 CET 2006

On 12/17/06, Joakim Tjernlund <joakim.tjernlund at transmode.se> wrote:
> "in some setups", that's the point. Our setup works fine with
> an embedded OF tree in u-boot. If I am to adapt to this new
> method of supplying the OF tree, not only will I have to repartion
> the flash to fit the tree in there, I also need to make sure
> that some 15-20 people learns this new concept for no real gain.
> It is nothing wrong with having the ability provide a OF tree
> at boot time, but forcing everyone to do so is. The
> most flexible way is to have both.

This shouldn't be too big a deal.  Add the code back for linking the
.dtb into the image.  Look in common/boot.c and add a check for if the
third bootm parameter is '-'.  If it is, then use the builtin section
for the .dtb address.  Then you can either use the builtin version, or
pass a new one.  We're not talking a lot of code here.

Alternately; your u-boot image does not totally fill the sectors you
have allocated for it.  Since your plan is to update u-boot and the
.dtb at the same time; modify your u-boot build procedure (I think by
using objcopy) to link your .dtb to a known address within the unused
part of the u-boot sectors (so that u-boot+dtb are in a single file)
and make sure the update procedure also changes the default bootm
command to include the known dtb address.

There are lots of options here; and the default code in u-boot is not
forcing you to do it in a particular way.


Grant Likely, B.Sc. P.Eng.
Secret Lab Technologies Ltd.
grant.likely at secretlab.ca
(403) 399-0195

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