[PATCH v2 08/11] binman: Support packaging U-Boot for scenarios like OF_PRIOR_STAGE

[Simon Glass]

Hi Bin,

On Sat, 8 May 2021 at 08:55, Bin Meng <bmeng.cn at gmail.com> wrote:
>
> Hi Simon,
>
> On Sat, May 8, 2021 at 11:47 PM Simon Glass <sjg at chromium.org> wrote:
> >
> > Hi Bin,
> >
> > On Sat, 8 May 2021 at 08:15, Bin Meng <bmeng.cn at gmail.com> wrote:
> > >
> > > For scenarios like OF_PRIOR_STAGE, no device tree blob is provided
> > > in the U-Boot build phase hence the binman node information is not
> > > available. In order to support such use case, a new Kconfig option
> > > BINMAN_DTB is introduced, to tell U-Boot build system that a device
> > > tree blob is explicitly required when using binman to package U-Boot.
> > >
> > > Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
> > >
> > > ---
> > >
> > > Changes in v2:
> > > - new patch: "binman: Support packaging U-Boot for scenarios like OF_PRIOR_STAGE"
> > >
> > >  Makefile    |  3 ++-
> > >  dts/Kconfig | 18 ++++++++++++++++++
> > >  lib/Kconfig |  2 +-
> > >  3 files changed, 21 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/Makefile b/Makefile
> > > index 3d88559b67..9043828675 100644
> > > --- a/Makefile
> > > +++ b/Makefile
> > > @@ -918,6 +918,7 @@ endif
> > >  endif
> > >  INPUTS-$(CONFIG_TPL) += tpl/u-boot-tpl.bin
> > >  INPUTS-$(CONFIG_OF_SEPARATE) += u-boot.dtb
> > > +INPUTS-$(CONFIG_BINMAN_DTB) += u-boot.dtb
> > >  ifeq ($(CONFIG_SPL_FRAMEWORK),y)
> > >  INPUTS-$(CONFIG_OF_SEPARATE) += u-boot-dtb.img
> > >  endif
> > > @@ -1161,7 +1162,7 @@ u-boot-dtb.bin: u-boot-nodtb.bin dts/dt.dtb FORCE
> > >  u-boot.bin: u-boot-dtb.bin FORCE
> > >         $(call if_changed,copy)
> > >  else
> > > -u-boot.bin: u-boot-nodtb.bin FORCE
> > > +u-boot.bin: u-boot-nodtb.bin $(if $(CONFIG_BINMAN_DTB),dts/dt.dtb) FORCE

What is this change for, specifically? Can you add a comment?

It seems to be overriding the qemu thing of not actually building a DT?

> > >         $(call if_changed,copy)
> > >  endif
> > >
> > > diff --git a/dts/Kconfig b/dts/Kconfig
> > > index 99ce75e1a2..84d43fc6a4 100644
> > > --- a/dts/Kconfig
> > > +++ b/dts/Kconfig
> > > @@ -19,6 +19,24 @@ config BINMAN
> > >         bool
> > >         select DTOC
> > >
> > > +config BINMAN_DTB
> > > +       bool
> > > +       depends on BINMAN
> > > +       default y if OF_PRIOR_STAGE
> > > +       help
> > > +         This option tells U-Boot build system that a device tree blob is
> > > +         explicitly required when using binman to package U-Boot.
> > > +
> > > +         This is not necessary in a common scenario where a device tree blob
> > > +         is provided in the arch/<arch>/dts directory for a specific board,
> > > +         where the binman node has been put in the board's device tree, aka
> > > +         an implicit way. However for a scenario like the board's device tree
> > > +         is not provided in the U-Boot source tree, but given to U-Boot in the
> > > +         runtime, e.g.: in the OF_PRIOR_STAGE case that the device tree blob
> > > +         is passed by a prior stage bootloader. For such scenario, we will
> > > +         need to provide a device tree blob containing binman node to describe
> > > +         how to package U-Boot.
> >
> > I don't fully understand the effect of this. Is binman (at build time)
> > using a binary DT provided by another build system? Or is it not
> > available at build time and binman cannot run?
>
> binman uses a DT provided by U-Boot, but that DT is only for binman if
> OF_PRIOR_STAGE. For OF_SEPARATE / EMBEDDED, we can include binman node
> there.
>
> You can check patch 10 for how it works.

OK I think I get it.

>
> >
> > The name is too vanilla I think. It should indicate that this is an
> > unusual situation.
>
> I cannot think of a good name :(

How about BINMAN_FAKE_FDT ?

Why do you need to turn off BINMAN_FDT?

Regards,
Simon