Re: [PATCH 1/1 RFC] treewide: Deprecate OF_PRIOR_STAGE

Ilias Apalodimas
2021-09-24T16:46:17Z

On Fri, Sep 24, 2021 at 04:46:58PM +0200, Heinrich Schuchardt wrote:
>
>
> On 9/24/21 3:10 PM, Ilias Apalodimas wrote:
> > At some point back in 2018 prior_stage_fdt_address and OF_PRIOR_STAGE got
> > introduced, in order to support a DTB handed over by an earlier stage boot
> > loader. However we have another option in the Kconfig (OF_BOARD) which has
> > identical semantics.
> >
> > A good example of this is RISC-V boards which during their startup,
> > pick up the DTB from a1 and copy it in their private gd_t. Apart from that
> > they also copy it to prior_stage_fdt_address, if the Kconfig option is
> > selected, which seems unnecessary(??).
> >
> > This is mostly an RFC, trying to figure out if I am missing some subtle
> > functionality, which would justify having 2 Kconfig options doing similar
> > things present.
> >
> > - Should we do this?
> > - Doesn't OF_BOARD and OF_PRIOR_STAGE practically mean "Someone else is
> > going to pass me my DTB". Why should we care if that someone is a prior
> > bootloader or runtime memory generated on the fly by U-Boot? It all
> > boils down to having a *board* specific callback for that.
> > - RISC-V binman should get rid of the option as well if we decide to go
> > though with this (but I have no idea what RISC-V expects there).
>
> Just replace CONFIG_OF_PRIOR_STAGE by CONFIG_OF_BOARD.

Ah thanks!

>
> > - return (ulong *)gd->arch.firmware_fdt_addr;

[...]

> > - else
> > - return (ulong *)&_end;
> > - }
> > + if (gd->arch.firmware_fdt_addr)
> > + return (ulong *)gd->arch.firmware_fdt_addr;
>
> (ulong *) makes no sense here. (void *) would be more adequate.
>

Yea I preserved what was already in there, since I thought that was gonna
require a different patch to fix. But Since I'll be moving these lines
away I might as well fix it.

> > # elif defined(CONFIG_OF_PRIOR_STAGE)
[...]
> > + /*
> > + * obsolete don't use this on newer boards. Prefer CONFIG_OF_BOARD
> > + * instead
> > + */
>
> This comment should be in Kconfig.

I'll add it on both. The point is prevent people from doing a similar
thing again, even if I miss the mail on the list!

Cheers
/Ilias
>
> Best regards
>
> Heinrich
>
> > gd->fdt_blob = (void *)(uintptr_t)prior_stage_fdt_address;
> > # endif
> > # ifndef CONFIG_SPL_BUILD
> >