[U-Boot] [PATCH] Honor /memory/reg node in DTB files

Wolfgang Denk
2010-12-08T21:00:06Z

Dear Deepak Saxena,

In message <4CFFD57C.1010601@mentor.com> you wrote:
>
> > Please explain: you can use the DT to tell Linux (or other OS) how
> > much memory they shoulduse, but you cannot use the same mechanism to
> > pass the same information to U-Boot?
>
> I'm not against U-Boot using this information, I'm just not sure how to
> do this without adding quite a bit of complexity to the code base. We
> would have to have U-Boot parse the memory nodes, validate them, check
> for overlapping regions, check for holes, etc. I'm not arguing that it
> is not doable, but wondering if adding this complexity is worth if the
> scanning of memory and passing that information to the kernel works for
> the majority of use cases. What I'm trying to do is support a special
> use case, so what about wrapping support for simply passing the memory
> nodes from the DT to the kernel around a CONFIG option
> (CONFIG_OF_MEMORY_PASSTHROUGH?) that can be enabled by system
> implementers who need this and are running on fairly controlled
> environments while the larger issue of how to use the DT is hashed out?

See my previous message to Hollis. If you really want U-Boot to keep
it's fingers off the /memory nodes in the DT, then simply do that. But
then please be consequent, add it for all architectures, and if
enabled, then without magic where U-Boot will sometimes to this and
other times do that. And provide documentation to the end user.

Best regards,

Wolfgang Denk

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