[U-Boot] [PATCH 6/8] ARM: bootm: allow skipping fdt memory node fixup

[Andre Przywara]

On Fri, 5 Jun 2015 08:12:25 -0600
Simon Glass <sjg at chromium.org> wrote:

Hi Simon,

thanks for taking a look.

> On 4 June 2015 at 17:58, Andre Przywara <osp at andrep.de> wrote:
> > From: Rob Herring <robh at kernel.org>
> >
> > Currently, u-boot will always fixup the DT memory node on ARM. If
> > the dtb has correct memory information, then we don't want or need
> > u-boot to touch the memory node. Allow platforms to skip this by
> > not filling in dram bank information.
> >
> > Signed-off-by: Rob Herring <robh at kernel.org>
> > Signed-off-by: Andre Przywara <osp at andrep.de>
> > ---
> >  arch/arm/lib/board.c     | 2 ++
> >  arch/arm/lib/bootm-fdt.c | 5 ++++-
> >  2 files changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c
> > index 37ea6e9..a3c7315 100644
> > --- a/arch/arm/lib/board.c
> > +++ b/arch/arm/lib/board.c
> 
> I don't think we should be patching this file now - everything should
> be on generic board.

Right, looking closer at this patch much of it is actually not
necessary. Having CONFIG_NR_DRAM_BANKS set to 0 automatically skips a
lot of the code already, so we don't need any extra gating.
Hope that there are no compilers which complain about zero-sized arrays.
The only thing that harms us is the final fdt_setprop(), which will
_clear_ the reg property in the memory node in this case.
So I replaced this patch by just skipping the reg property setting if
the number of banks is 0 in common/fdt_support.c.
From looking at all callers of fdt_fixup_memory_banks() this looks like
a safe approach. Any objections?
I will send the replaced patch with the next revision.

Cheers,
Andre.

> 
> > @@ -191,8 +191,10 @@ typedef int (init_fnc_t) (void);
> >
> >  __weak void dram_init_banksize(void)
> >  {
> > +#if  
> >         gd->bd->bi_dram[0].start = CONFIG_SYS_SDRAM_BASE;
> >         gd->bd->bi_dram[0].size =  gd->ram_size;
> > +#endif
> >  }
> >
> >  __weak int arch_cpu_init(void)
> 
> [snip]
> 
> Regards,
> Simon