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

Steve Sakoman steve at sakoman.com
Mon Sep 27 23:17:57 CEST 2010


On Mon, 2010-09-27 at 11:02 +0200, Wolfgang Denk wrote:
> Dear "V, Aneesh",
> 
> In message <FF55437E1F14DA4BAEB721A458B6701706FCA3B8E5 at dbde02.ent.ti.com> you wrote:
> > 
> > > SDRAM configuration must be done while still running from NOR, i. e.
> > > before relocation. Only then free reconfiguration, auto-sizing etc.
> > > is
> > > possible.
> >
> > We shall rework the patch to do SDRAM size calculation as part of 
> > 'lowlevel_init' that is called before relocation. I hope that should 
> > solve the problem. 
> 
> No. This is not where it belongs. RAM initialization is done by the
> dram_init() function, which is an entry in the init_sequence[] array;
> see arch/arm/lib/board.c
> 
> > Please note that we are always running from SDRAM because none of 
> > the OMAP4 boards so far have any XIP device.
> 
> I see.

I fear that all this discussion of what might happen someday with a XIP
NOR implementation on OMAP4 may have distracted from the consideration
of this patch for a real problem on today's hardware!  The current Panda
implementation returns an incorrect value for system ram size.

The subject patch does indeed set the ram size properly in the OMAP4
specific dram_init() function.  As Wolfgang says above, this is the
proper place.  If there are no other objections we should try to get
this integrated.

Regards,

Steve



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