[U-Boot-Users] Warning for mpc8360emds users: fdt-cmd from u-boot-fdt.git

Jerry Van Baren
2007-04-04T16:17:35Z

Timur Tabi wrote:
> Jerry Van Baren wrote:
>
>> As a result, if you pull an update from the master u-boot repository,
>> you will get the new fdt command, libfdt support, *and modified bootm*
>> command. While this shouldn't be a bad thing, it *is not* backward
>> compatible with CONFIG_OF_FLAT_TREE.
>
> I'm a little confused. CONFIG_OF_FLAT_TREE is needed to boot any
> powerpc kernel. Are you saying that the two options are mutually
> exclusive? Shouldn't CONFIG_OF_LIBFDT be a subset (instead of an
> alternative) to CONFIG_OF_FLAT_TREE? That is, you need to define
> CONFIG_OF_FLAT_TREE in order for CONFIG_OF_LIBFDT to be recognized?
>
> Maybe I should have been paying more attention to your libfdt work, but
> I was assuming you were just going to alter the back-end handling of OF
> trees, not break existing code.

Hi Timur,

Using CONFIG_OF_FLAT_TREE results in an unchanged u-boot image, no
libfdt, no "fdt" command, backwards compatibility.

The incompatibility with CONFIG_OF_LIBFDT is that "bootm" does *not*
auto-generate nodes ("chosen", "u-boot-env", and "bd_t") when it runs.
With CONFIG_OF_LIBFDT, I expect the boot script or the user to use the
sequence:
* "fdt addr" command to set the blob address
* "fdt chosen" to generate/augment the chosen node
* "fdt env" to generate the u-boot-env node (optional)
* "fdt bd_t" to generate the bd_t node (optional)

I view autogenerating fdt entries inside "bootm" as being evil.
Obviously, if there are enough people on the Dark Side to overwhelm me,
that can be changed.

NOTE: I've probably screwed up the multi-image. Note to self, fix it -
need to find the fdt blob in a multi-image and implicitly set the "fdt
addr" to it.

Best regards,
gvb