[U-Boot] [PATCH 12/26] ARM: add relocation support

Wolfgang Wegner
2010-09-16T10:18:10Z

On Thu, Sep 16, 2010 at 07:54:03PM +1000, Graeme Russ wrote:
[...]
> I have a 'cold-boot' parameter which is set by the reset vector code. I can
> use this to selectively skip 'once-only' initialisation
[...]
> I don't doubt that you are entirely correct. But there are many ways to
> skin a cat. My problem was to reduce the build->burn->boot development time
> where the burn phase was the longest. The low level boot and device
> initialisation all works and hasn't changed in quite a while, so I can rely
> on what is on my (nearly a year) old image.

I see this feature not only nice to speed up development, sometimes
it also comes in really handy for production, too - if you have to
struggle with debugging tools that are either plain too stupid to
program some flash devices or are much slower than U-Boot, you
can simply run a specially built version from RAM and/or provide it
with an environment in RAM to do all the actual flashing for the board
production.

> A common framework (within the bounds of cross-architecture limitations)
> would be nice

For some targets, there may be fragments present in the code
when searching for CONFIG_MONITOR_IS_IN_RAM, which statically
disables all the low-level initialization to allow U-Boot being
loaded from a first-stage loader or debugger. But beware, it is
not always functional out-of-the-box.

Regards,
Wolfgang