[U-Boot] [PATCH v3 09/14] tegra20: add u-boot.t2 target

[Simon Glass]

Hi Allen,

On Mon, Jun 11, 2012 at 12:22 PM, Allen Martin <amartin at nvidia.com> wrote:

> On Sat, Jun 09, 2012 at 12:12:09PM -0700, Simon Glass wrote:
> > Hi Allen,
> >
> > On Fri, Jun 8, 2012 at 2:16 PM, Allen Martin <amartin at nvidia.com<mailto:
> amartin at nvidia.com>> wrote:
> > Add target for tegra20 u-boot image.  This is a concatenation of tegra
> > spl and normal u-boot binaries.
> >
> > Signed-off-by: Allen Martin <amartin at nvidia.com<mailto:
> amartin at nvidia.com>>
> > ---
> >  .gitignore                      |    1 +
> >  Makefile                        |   11 +++++++++++
> >  board/nvidia/seaboard/config.mk<http://config.mk> |    1 +
> >  3 files changed, 13 insertions(+)
> >  create mode 100644 board/nvidia/seaboard/config.mk<http://config.mk>
> >
> > diff --git a/.gitignore b/.gitignore
> > index 0f32fd8..b9192bf 100644
> > --- a/.gitignore
> > +++ b/.gitignore
> > @@ -39,6 +39,7 @@
> >  /u-boot.ais
> >  /u-boot.dtb
> >  /u-boot.sb<http://u-boot.sb>
> > +/u-boot.t2
> >
> > What does t2 mean? If it is a binary file of some sort  perhaps
> u-boot-t2.bin would be better?
>
> It's just means "tegra2".  I was following the convention that other
> SPL builds use.  I don't have a strong opinion on the name though.
>

OK, still would prefer a .bin on the end, but up to you.


>
> > +ifeq ($(CONFIG_OF_SEPARATE),y)
> > +T2_UBOOT=$(obj)u-boot-dtb.bin
> > +else
> > +T2_UBOOT=$(obj)u-boot.bin
> > +endif
> >
> > What is this logic for? The dtb file is separate but that doesn't
> > necessarily mean that it must be immediately after the U-Boot
> > image. We provide other options for packaging it, like
> > getenv(). Maybe if you want to create this composite binary you
> > should change its name (u-boot-dtb-t2.bin or u-boot-t2.bin) to
> > indicate what it contains?
>
> This just picks up the name of the u-boot binary so it glues the SPL
> to the right thing depending if devicetree is in use or not.
>

OK, to avoid confusion I think you should change the name to include the
-dtb or not, rather than having a filename without the -dtb part which does
in fact include a dtb.

>
> >
> > +$(obj)u-boot.t2:       $(obj)spl/u-boot-spl.bin $(T2_UBOOT)
> > +               $(OBJCOPY) ${OBJCFLAGS} --pad-to=$(PAD_TO) -O binary
> $(obj)spl/u-boot-spl $(obj)spl/u-boot-spl-pad.bin
> > +               cat $(obj)spl/u-boot-spl-pad.bin $(T2_UBOOT) >
> $(obj)u-boot.t2
> > +               rm $(obj)spl/u-boot-spl-pad.bin
> > +
> >
> > I echo Stephen's comments. But also SPL is supposed to load U-Boot,
> > so shouldn't this t2 binary do that?
>
> The t2 binary is the SPL and u-boot concatenated together into one
> binary.  The whole thing will get loaded into memory by the tegra
> BootROM.  The SPL knows the address of the real u-boot at compile time
> and uses that as the address for the Cortex A9 to jump to when it
> comes out of reset.
>

OK I see, makes sense. I am interested in your comments as to whether we
might move to a 'true SPL' later, where U-Boot is actually loaded by SPL.


> -Allen
> --
> nvpublic
>

Regards,
Simon