Re: [PATCH 1/3] treewide: Remove OF_PRIOR_STAGE from RISC-V boards

[Ilias Apalodimas <ilias.apalodimas@linaro.org>]

Hi Zong, 

[...]

> > diff --git a/board/sifive/unleashed/unleashed.c b/board/sifive/unleashed/unleashed.c
> > index 8cd514df3005..7e89c3f740a7 100644
> > --- a/board/sifive/unleashed/unleashed.c
> > +++ b/board/sifive/unleashed/unleashed.c
> > @@ -116,12 +116,10 @@ int misc_init_r(void)
> >
> >  void *board_fdt_blob_setup(void)
> >  {
> > -       if (IS_ENABLED(CONFIG_OF_SEPARATE)) {
> > -               if (gd->arch.firmware_fdt_addr)
> > -                       return (ulong *)gd->arch.firmware_fdt_addr;
> > -               else
> > -                       return (ulong *)&_end;
> > -       }
> > +       if (gd->arch.firmware_fdt_addr)
> > +               return (void *)gd->arch.firmware_fdt_addr;
> > +       else
> > +               return (void *)&_end;
> >  }
> 
> I was wondering if we need to check CONFIG_OF_BOARD here? I'm not sure
> whether we should distinguish the value of a1 register which is
> meaningless. It means that if we don't expect the device tree to be
> passed by prior stage, then the a1 register might be a trash value at
> the beginning, so it would still return the arch.firmware_fdt_addr
> here, rather than _end. 

I thought about it as well.  Those boards were configured up to now with
'CONFIG_OF_SEPARATE'.  Which means we are looking at an existing issue?
IOW the device tree was passed as part of U-Boot,  which would mean a1 would
have had thrash as well.  Maybe a1 always has a valid DT on those boards
so we never noticed?


> And do you think that we should enable the
> CONFIG_OF_BOARD for unmatched and unleashed? Because it seems to me
> that we actually pass the device tree by prior stage (i.e. OpenSBI).

Yes in that case what you request makes sense for unmatched/unleashed.
Return gd->arch.firmware_fdt_addr in OF_BOARD is selected otherwise return
_end (instead of the current check).
If that sounds good to you I'll send a v2

[...]

Regards
/Ilias