[U-Boot] [PATCH] ARMV7: OMAP4: Calculate SDRAM size

Steve Sakoman steve at sakoman.com
Sun Sep 26 16:57:24 CEST 2010


On Sun, 2010-09-26 at 16:37 +0200, Wolfgang Denk wrote:
> Dear Nishanth Menon,
> 
> In message <4C9F3E4F.3040403 at gmail.com> you wrote:
> >
> > > I think you are referring to SDRAM initialization. Yes, it is assumed
> > > that SDRAM initialization(at least the DMM part of it) is done before
> > > the call to sdram_size(). The right location for this seems
> > > to be the initial part of sdram_init().
> > 
> > thanks for the clarification.. NOR boot is usually going to have initial 
> > part in XIP -> we'd traditionally relocate to SDRAM before the call to 
> > sdram_size() happens.
> 
> Yes, this was the way how many ARM boards id, and this is what I'm
> trying to explain: this is WRONG.
> 
> SDRAM configuration must be done while still running from NOR, i. e.
> before relocation. Only then free reconfiguration, auto-sizing etc. is
> possible.

I'll make sure that this is done properly when(if?) a patch series for
an OMAP4 board with NOR boot is prepared.

Getting back to the subject patch, though :-)

This patch fixes a bug in the current Panda board support in rc2.
Without this patch U-boot will return an erroneous size for available
RAM.  We should consider it for inclusion as soon as practical.

Regards,

Steve




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