[U-Boot] [PATCH v8 31/31] arm: Remove duplicated start.S code

[Benoît Thébaudeau]

On Friday, March 1, 2013 4:50:44 PM, Benoît Thébaudeau wrote:
> Hi Albert,
> 
> On Friday, March 1, 2013 4:46:07 PM, Albert ARIBAUD wrote:
> > Hi Benoît,
> > 
> > On Fri,  1 Mar 2013 13:10:40 +0100, Benoît Thébaudeau
> > <benoit.thebaudeau at advansee.com> wrote:
> > 
> > > Factorize start.S code as much as possible.
> > > 
> > > Functions that may need to be customized for some start.S are defined
> > > weak
> > > for
> > > that purpose.
> > > 
> > > relocate_code_prepare() and relocate_code_finish() are introduced as
> > > hooks
> > > to be
> > > executed at the beginning and at the end of relocate_code() if needed by
> > > some
> > > start.S, e.g. for special cache or MMU operations.
> > 
> > NAK.
> > 
> > 1. I don't like this idea of planting hooks inside relocate-code().
> > This function is about relocating code, not about MMU stuff. If there
> > are any MMU steps to be performed between calls to board_init_f(),
> > relocate_code() or board_init_r(), I want them laid out as calls of
> > their own right in crt0.S.
> 
> I also don't like it. The finish hook was used by SMDK6400 before it was
> removed, and the prepare hook is still used by pxa.
> 
> So is it OK for you if I just drop relocate_code_finish() and move and
> rename the call to relocate_code_prepare() to crt0.S?
> 
> > 2. If we're going to factorize out relocate_code() from the various
> > start.S files, I want it moved not in crt0.S but in its own file.
> 
> It is not in crt0.S, but in arch/arm/include/asm/start_marco.S, which is
> almost its own file apart from another macro.
> 
> > This
> > way, i) people can easily create binaries which use crt0.S but do not
> > relocate, ii) people who want to make relocate_code() a C function
> > will have it easier, and iii) crt0.S keeps being the ugly ASM glue
> > needed for flash inits, relocation and RAM inits to have a C proper
> > run-time environment.
> 
> Which is already the case with this implementation?

And in case you ask, with relocate_code() as a function in its own file instead
of a macro called from start.S, it does not work because of the _start-relative
word values that require relocate_code() to be in _start's section.

Best regards,
Benoît