[U-Boot] [PATCH 3/6] SPL: Port SPL framework to powerpc

Stefan Roese
2012-08-24T07:01:36Z

Hi Tom,

On 08/23/2012 11:39 PM, Tom Rini wrote:
> On 08/23/2012 01:12 AM, Stefan Roese wrote:
>
>> This patch enables the SPL framework to be used on powerpc platforms
>> and not only ARM.
> [snip]
>> +#ifdef CONFIG_ARM
>> gd = &gdata;
>> +#endif
>
> So, here's what I don't understand. On ARM, in general, we can't rely
> on the global data pointer register (r8) to be set to a useful value, so
> we do the above to ensure it points to something useful. Are you always
> able to rely on r2 it looks like pointing to something useful? Or do
> you take care of this much earlier on in powerpc? Thanks!

You are correct, I missed something here. r2 was still configured to the
value written to it from the "real" U-Boot (pointing to internal SRAM).

I can't use the code in preloader_console_init() though to setup the gd
pointer. As I need to write some values in gd *before* calling
preloader_console_init() (mainly clocks for serial driver). And since
this "gd stuff" is quite platform specific, we should probably move this
into an platform/arch spl file instead. As you also mentioned in another
reply to create an arch/${ARCH}/lib/spl.c file.

What do you think? Can you move this gd init stuff into such a common
ARM spl file in the next patchset version?

Thanks,
Stefan