[PATCH v5 26/26] fdt: Don't call board_fdt_blob_setup() without OF_BOARD

[Simon Glass]

Hi Ilias,

On Tue, 26 Oct 2021 at 07:56, Ilias Apalodimas
<ilias.apalodimas at linaro.org> wrote:
>
> Hi Simon,
>
> As I said here [1], this is moving on an entirely different direction I had
> in mind. I'd much prefer starting the discussions for a solution that
> allows us to scale.

I am missing the point here. Is there something in the plans that I
don't know about?

> FWIW I think the current code is still not clean for my taste.  Commit
> 3b595da441cf ("fdtdec: allow board to provide fdt for CONFIG_OF_SEPARATE")
> allowed this function to be used regardless of the config options.  IMHO we
> should have 2 clear options:
> - U-Boot provides the DTB

Supported with: OF_SEPARATE

> - It's somehow passed over to U-Boot

Supported with: OF_SEPARATE + OF_BOARD

I actually hit this problem with my qemu testing, in that it is
actually not possible to use U-Boot's devicetree without hacking the
code. We need to be able to select this feature explicitly, or turn it
off, at least for development.

Regards,
Simon


>
> On Mon, Oct 25, 2021 at 06:23:44PM -0600, Simon Glass wrote:
> > At present this override function is called even when OF_BOARD Is not
> > enabled. This makes it impossible to disable this feature and in fact
> > makes the OF_BOARD option useless.
> >
> > Reinstate its intended purpose, so that it is possible to switch between
> > the appended devicetree and one provided by the board's custom function.
> >
> > Signed-off-by: Simon Glass <sjg at chromium.org>
> > ---
> >
> > Changes in v5:
> > - Add new patches to clean up fdtdec_setup() and surrounds
> >
> >  include/fdtdec.h |  7 +++++--
> >  lib/fdtdec.c     | 17 +++++++++++------
> >  2 files changed, 16 insertions(+), 8 deletions(-)
> >
> > diff --git a/include/fdtdec.h b/include/fdtdec.h
> > index 386f6611294..b2faa84008e 100644
> > --- a/include/fdtdec.h
> > +++ b/include/fdtdec.h
> > @@ -1170,8 +1170,11 @@ int fdtdec_resetup(int *rescan);
> >
> >  /**
> >   * Board-specific FDT initialization. Returns the address to a device tree blob.
> > - * Called when CONFIG_OF_BOARD is defined, or if CONFIG_OF_SEPARATE is defined
> > - * and the board implements it.
> > + * Called when CONFIG_OF_BOARD is defined.
> > + *
> > + * The existing devicetree is available at gd->fdt_blob
> > + *
> > + * @returns new devicetree blob pointer
> >   */
> >  void *board_fdt_blob_setup(void);
> >
> > diff --git a/lib/fdtdec.c b/lib/fdtdec.c
> > index 067c27d0aa3..da36dffec62 100644
> > --- a/lib/fdtdec.c
> > +++ b/lib/fdtdec.c
> > @@ -1203,11 +1203,12 @@ static int uncompress_blob(const void *src, ulong sz_src, void **dstp)
> >       return 0;
> >  }
> >
> > -/*
> > - * For CONFIG_OF_SEPARATE, the board may optionally implement this to
> > - * provide and/or fixup the fdt.
> > +/**
> > + * fdt_find_separate() - Find a devicetree at the end of the image
> > + *
> > + * @return pointer to FDT blob
> >   */
> > -__weak void *board_fdt_blob_setup(void)
> > +static void *fdt_find_separate(void)
> >  {
> >       void *fdt_blob = NULL;
> >  #ifdef CONFIG_SPL_BUILD
> > @@ -1623,11 +1624,15 @@ int fdtdec_setup(void)
> >       int ret;
> >
> >       /* The devicetree is typically appended to U-Boot */
> > -     if (IS_ENABLED(CONFIG_OF_SEPARATE) || IS_ENABLED(CONFIG_OF_BOARD))
> > -             gd->fdt_blob = board_fdt_blob_setup();
> > +     if (IS_ENABLED(CONFIG_OF_SEPARATE))
> > +             gd->fdt_blob = fdt_find_separate();
> >       else /* embed dtb in ELF file for testing / development */
> >               gd->fdt_blob = dtb_dt_embedded();
> >
> > +     /* Allow the board to override the fdt address. */
> > +     if (IS_ENABLED(CONFIG_OF_BOARD))
> > +             gd->fdt_blob = board_fdt_blob_setup();
> > +
> >       if (!IS_ENABLED(CONFIG_SPL_BUILD)) {
> >               /* Allow the early environment to override the fdt address */
> >               gd->fdt_blob = map_sysmem(env_get_ulong("fdtcontroladdr", 16,
> > --
> > 2.33.0.1079.g6e70778dc9-goog
> >
>
> [1] https://lore.kernel.org/u-boot/YXekTkeL73NM0UOU@apalos.home/
>
> Regards
> /Ilias