[ELDK] From which version does u-boot support Open Firmware?

[林志平]

Thanks for your reply!

2009/11/2 Wolfgang Denk <wd at denx.de>

> Dear =?GB2312?B?wdbWvsa9?=,
>
> please post U-Boot related questions on the U-Boot mailing list.
>
> In message <8148211e0911012034q72b3b9e2tec1b09cd98f7fa9f at mail.gmail.com>
> you wrote:
> >
> > I found that uboot which supports Open Frimware use R3 and R4 to pass dtb
> > and kernel address to the kernel.
>
> Please be careful with your terms. U-Boot does NOT support Open
> Firmware - what sort of support should that be, by the way?
>
Sorry, I am confused with these concepts. I suppose Open Firmware to be the
rule of passing parameters to linux kernel from bootloader. While it is not
that case maybe.
The new version of linux kernel has merged ppc into powerpc, along with the
different rule of passing parameters.
So the older versions of UBoot may not able to port linux kernel2.6 with
arch/powerpc.
And I meant that from which version on does UBoot support the arch/powerpc.

> What U-Boot does is to support flattened device trees as a  means  of
> passing  hardware  information to the Linux kernel. Note that this is
> an architecture dependent feature.
>
> > while the uboot which donot support Open Firmware use
> >  /*
> >   * Linux Kernel Parameters (passing board info data):
> >   *   r3: ptr to board info data
> >   *   r4: initrd_start or 0 if no initrd
> >   *   r5: initrd_end - unused if r4 is 0
> >   *   r6: Start of command line string
> >   *   r7: End   of command line string
>
> Current versions of U-Boot support both booting with (for recent
> kernels) or without (for older kernels) device tree image.
>
> > And I find the source code of uboot1.3.1 and uboot 2009.08 have great
> > difference.
>
> Indeed. This is to be expected - there  are  more  than  2  years  of
> development  between  these  two versions, so you can indeed expect a
> LOT of changes (to be precise: this period covers 5032  commits  from
> 284  developers;  a  total of 685862 lines were added, 306543 removed
> and 379319 changed).
>
>
> 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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> understand it.                    - Queen Juliana of the Netherlands.
>