[U-Boot] CONFIG_SYS_XIP_BOOT for when it's a choice?

[Tom Rini <trini@ti.com>]

On Mon, Apr 07, 2014 at 07:05:36PM +0200, Wolfgang Denk wrote:
> Dear Tom,
> 
> In message <20140305172806.GY16805@bill-the-cat> you wrote:
> > 
> > I'm looking over some patches for am43xx to enable the case of non-SPL
> > XIP booting and this means we start getting code that's shared with
> > am335x that looks like:
> 
> What exactly do you mean by "non-SPL XIP booting"?  Is this not the
> standard boot mode which has actually been the first (and only one)
> that U-Boot has ever been designed for, like booting from a ROM (like
> parallel NOR flash)?  Because the we do exactly that: we execute the
> code as is from the boot device...

Exactly.  But most modern platforms are not XIP booting by default, if
ever.  When it is, it's a special case and needs the code we usually
only call in SPL (say memory controller init) linked in.  Today this is
done with say:
#if defined(CONFIG_SPL_BUILD) || defined(CONFIG_NOR_BOOT)
...
#endif
on am335x.  Looking at am43xx we have both traditional NOR and QSPI NOR
as boot options, along with SD/NAND/various-peripheral-boots.

-- 
Tom
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