[U-Boot] [PATCH] powerpc: do not fixup NULL ptrs

Joakim Tjernlund
2010-11-04T10:54:44Z

>
> Wolfgang Denk <wd@denx.de> wrote on 2010/11/04 10:57:42:
> >
> > Dear Joakim Tjernlund,
> >
> > In message <OF5324EC0A.37C044B2-ONC12577D1.0031F002-C12577D1.00326E3D@transmode.se> you wrote:
> > >
> > > > 4 nops after _start does the trick, i.e. the board is up and running fine.
> > ...
> > > How is this going? If nothing else I think you should send
> > > a patch for 83xx, adding the 4 nop's as your(and mine) board is
> > > broken otherwise. Freescale guys seems busy with other things so
> > > I think this is the best thing to do.
> >
> > I don't like the idea of adding such code without any understanding
> > why it would be needed for some boards, while it is not needed for
> > others.
>
> Sure, but until freescale or someone else with eq. and motivation
> researches it, we are stuck. I am not sure anyone else has tried
> 83xx based boards yet. If someone has please report. Also
> include weather booted from NAND or NOR, CPU type(e300cX) and
> what reset vector is used.
>
> >
> > Is it really needed at _start? Or can these NOPs be anywhere, and are
> > just needed to adjust some alignment?
>
> no, the nops has to be directly after _start:
> . = EXC_OFF_SYS_RESET
>
> .globl _start
> _start: /* time t 0 */
> nop
> nop
> nop
> nop
>
> My theory is that e300c2(no FPU) CPUs configured for low
> boot vector, 0x100, really uses 0x110 instead.

hmm, what if a board decides to do a soft reset anyway, perhaps by mistake.
Would it not be a good thing if u-boot could handle that too?