[PATCH] Revert "fdtdec: drop needlessly convoluted CONFIG_PHANDLE_CHECK_SEQ"

[Simon Glass]

Hi Tom,

On Sun, 3 Jul 2022 at 06:43, Tom Rini <trini at konsulko.com> wrote:
>
> On Sun, Jul 03, 2022 at 02:32:42AM -0600, Simon Glass wrote:
> > Hi,
> >
> > On Sun, 3 Jul 2022 at 02:25, Simon Glass <sjg at chromium.org> wrote:
> > >
> > > The fdt_path_offset() function is slow since it must scan the tree.
> > > This substantial overhead now applies to all boards.
> > >
> > > The original code may not be ideal but it is fit for purpose and is only
> > > needed on a few boards.
> > >
> > > We should revert this in time for the release.
> > >
> > > This reverts commit 26f981f295d00351b6f0c69b5317b254b2361cc0.
> > >
> > > Signed-off-by: Simon Glass <sjg at chromium.org>
> > > ---
> > >
> > >  configs/am65x_evm_a53_defconfig  | 1 +
> > >  configs/evb-ast2600_defconfig    | 1 +
> > >  configs/sama7g5ek_mmc1_defconfig | 1 +
> > >  configs/sama7g5ek_mmc_defconfig  | 1 +
> > >  lib/Kconfig                      | 7 +++++++
> > >  lib/fdtdec.c                     | 7 +++++--
> > >  6 files changed, 16 insertions(+), 2 deletions(-)
> >
> > Please also see the context here:
> >
> > https://patchwork.ozlabs.org/project/uboot/patch/20201111142605.17034-1-a-govindraju@ti.com/
>
> Previously when we've had issues of making the fast path slow, people
> have posted measurements of before/after in order to demonstrate the
> problem.  Can we please get some logs of before/after and various
> possible solutions?  Thanks.

Well this code is not needed at all for all but four boards. It does a
very expensive check of the DT and this can happen before relocation,
or is SPL. I don't have a board to test with at present, but I expect
it would cost 10s of milliseconds on AT91, for example. Also, it just
isn't needed, which is why I suggest a revert.

Regards,
Simon