[U-Boot-Users] U-Boot-NG ?

Carsten Schlote
2007-07-03T15:35:27Z

Hi Sascha,

> No, the scripts work here, but I did not find where
> MAXPAGESIZE and COMMONPAGESIZE are defined, they must come
> from the linker.

That was, what I meant. It's somewhere hacked into LD.

> Do you need to define MAXPAGESIZE and COMMONPAGESIZE aswell
> or only CONSTANT? I would prefer hardcoding the values
> directly in the linker script. They are needed only for the
> sandbox target, but u-boot.lds.h is included for all architectures.

So it is better to use the hard-coded values in the linker script. At
least as long as it takes for main-stream LD to support this fine
extension.

> btw I just read your wiki and 'sandbox' really is the better
> name for this target ;)

A simulation sandbox with a real GDB and host OS is really some kind of
'must have' :-) Most high-level stuff can be developed with it, and just
the final tests need to be done on the target. And with some tweaking
the 'sanbox' target should compile and run on all POSIX platforms, not
just Linux. So calling it 'arch=linux' would be somehow limiting.

The relocation issue:

For the real targets U-Boot should be relocateable. Why? Simply because
I might want to run something else than Linux on a target. U-Boot
shouldn't occupy IRQ Vectors in RAM, nor should it be located in the
middle of available RAM - simply because my 'OS' might want to use it as
a single large block.

On most CPU architectures the IRQ/Except vectors can be placed into RAM
- most times at address 0 and up. Most operating systems also link and
load to the bootom of memory. The only place, which is rarely used by
other code, is the top of memory. That's why U-Boot should relocate to
this location whenever possible.

Regards
Carsten

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