[U-Boot] [PATCH] overo: add SPL support

Andreas Müller schnitzeltony at gmx.de
Tue Dec 20 13:39:39 CET 2011


On Tuesday, December 20, 2011 01:06:07 PM you wrote:
> Dear Andreas,
> 
> In message <201112201253.46991.schnitzeltony at gmx.de> you wrote:
> > I agree to your concerns but - as I understood Steve Sakoman - here the
> 
> > situation is slightly different:
> I think you misunderstand.
Yes I think too :-)
> 
> > At elder overo boards TWL4030 RTC irq is connected to gpio112.
> > Unfortunately this pin is also used for binary revision detection.
> > Therefore we need to send 'shut-up' to TWL4030 via i2c to avoid reading
> > wrong revision. In SPL this must be done *before* SDRAM (timing) is set
> > up, because the type of SDRAM is revision dependent.
> 
> My suggestion was to check if memory initialization can not rather be
> done _without_ reading (and without otherwise knowing) the board type
> or revision.  Usually this is possible, and I always prefer such
> auto-adjusting solutions over hard-wired approaches that break down
> when any of the expected inout data is not correct or not available.
> 
Dear Wolfgang,

I don't know if I want to jump also into these changes now - especially since 
I am quite new here..
But for my intererst - since it seems more error tolerant: How is SDRAM timing 
set up without exactly knowing what type is connected? Is there a good example 
implementation in u-boot(-spl)?

Best regards

Andreas


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