[U-Boot] [PATCH 2/2 RESEND] SPL: Allow user to disable CPU support library

[Marek Vasut <marek.vasut@gmail.com>]

On Monday, September 19, 2011 08:13:45 PM Scott Wood wrote:
> On 09/16/2011 05:48 PM, Marek Vasut wrote:
> > On Saturday, September 17, 2011 12:07:52 AM Scott Wood wrote:
> >> You have no idea why I'd like to be extremely selective with what I
> >> include in a 4K binary?
> > 
> > That I do understand -- but that kind of selection is there.
> > 
> >> It's not about avoiding particular files.  It's about including
> >> *nothing* but what is explicitly asked for through some SPL-specific
> >> CONFIG symbol.  Maybe that includes everything in arch/$(ARCH)/cpu.
> >> Maybe it includes nothing in there.  More likely, it includes just a
> >> fraction of it.
> > 
> > The stuff in arch/arm/cpu should be exactly what you need, nothing more !
> 
> This is "spl/", not "arch/arm/spl/", so let's not reason from one
> architecture, much less the subset of that architecture that has already
> been made to work with spl/ -- there are 14 different instances of
> arch/arm/cpu/$(CPU).

I don't think I follow you on this one really -- are we still discussing the 
inclusion/non-inclusion of the cpu-specific library in the SPL, right ?
> 
> We will not want everything we normally pull from
> arch/powerpc/cpu/mpc85xx to go into an 85xx NAND SPL, for example.  But
> we will want some small portion of it.

Then you adjust the makefile there by ifdef CONFIG_SPL_BUILD
> 
> My understanding of how spl/ is meant to work is that each directory's
> makefiles will use special SPL config symbols to decide what individual
> objects (if any) to include.  It's not clear to me why we need a
> directory-level control.  Maybe it would be the most convenient way to
> implement it for something that is well-encapsulated and arch-neutral
> (thus only one instance to worry about), where the odds of a subset
> being useful are slim, but it doesn't seem appropriate here.

See above, you use CONFIG_SPL_BUILD to select that in the makefile.
> 
> Whether it's file or directory based, everything should be off by
> default.  Boards should ask for what they want, not what they want to
> exclude.

Actually, this being a rare case where you want it excluded, it's better the way 
it is.

> 
> -Scott

Cheers