[U-Boot-Users] Can U-boot Autodetect arch/ppc versus arch/powerpc from info in the uImage?
wd at denx.de
Mon Dec 3 22:36:14 CET 2007
In message <D61182AC8012EA4EBC531B3AF23BE109480232 at tranzeo-mail2.12stewart.tranzeo.com> you wrote:
> I have looked at some of the u-boot code for booting up a linux kernel.
> It appears that the determination of whether or not to make use of
> flattened device tree (fdt) in the boot is a compile time selection.
No, this is not the case. You can use a FDT-enabled U-Boot to boot
kernel images which use a FDT, and of course such that don't, too.
> Can we determine during runtime from info in the uImage whether the
> linux kernel was built as arch/ppc or as arch/powerpc and then select
> the fdt support accordingly?
No. There is no such information available in the current image
> It will soon be possible to build a U-Boot for one or the other (for
> ppc4xx family). I think I will need to implement a U-Boot that will
This is not correct. You can build U-Boot without FDT-support, and
this will only work with old (arch/ppc) kernels, or with arch/powerpc
kernels using the bootwrapper (cuImage). Or you can build U-Boot
*with* FDT-support, which can do exactly the same, *plus* directly
boot FDT enabled Linux kernels.
> I think we need the U-Boot to be able to support both but detect which
> one the uImage was built under.
The first part of the sentence is true, and describes the current
state of things, and the second part is IMO not needed.
> In the image.h file, there appears to only be one selection for powerpc
> so there will likely be need for some other "magic" to make this work.
> Has anyone checked into this before, or come up with a workable
I see no need for any such changes.
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
Disc space - the final frontier!
More information about the U-Boot