[Question] TI's u-boot.img is built twice

[Masahiro Yamada]

On Fri, Sep 22, 2023 at 2:27 PM Neha Malcom Francis <n-francis at ti.com> wrote:
>
> Hi Masahiro
>
> On 21/09/23 21:06, Masahiro Yamada wrote:
> > Hi.
> >
> > Since the TI platform migrated to binman,
> > u-boot.img is built twice.
> >
> > It is created by "mkimage -E",
> > then overwritten by binman.
> >
> >
> > So, the data are embedded in the FIT structure
> > instead of being appended.
> >
> > Is this intentional?
> >
> > To me, it looks weird.
> >
> >
>
> I haven't added the fit,external-offset property in the binman.dtsi so it was
> not appended as external data and I did not find reason to. Is there any benefit
> in having the data appended than embedded?



Placing payload data outside the FIT structure is a U-Boot hack.


The motivation was explained in the commit log of
722ebc8f84d5bccd2e70fad1079a0dd40cceddec



Before TI migrated to binman,
u-boot.img was the "payload outside" structure
but it is not any more.

I do not mind the implementation details as long as
U-Boot is able to boot the Linux kernel.


I was just suffering from the AM64-SK boot failure
(as I asked in another thread) and just noticed
something odd when I was poking the SPL code.


At least, .u-boot.img.cmd is not telling the truth.

Usually, the build command is saved in a *.cmd file
but this does not reflect the reality, because
it is binman that created the final u-boot.img


$ cat .u-boot.img.cmd
cmd_u-boot.img := ./tools/mkimage -f auto -A arm -T firmware -C none
-O u-boot -a 0x80800000 -e 0x80800000 -p 0x0 -n "U-Boot
2023.10-rc4-00047-gb9b83a86f0-dirty for am64x board" -E  -b
arch/arm/dts/k3-am642-evm.dtb -b arch/arm/dts/k3-am642-sk.dtb  -d
u-boot-nodtb.bin u-boot.img >/dev/null


I will not track it down any further, though.
It is too complicated.






> >
> >
> > To confirm it, apply the following hack.
> >
> > Since u-boot.img is overwritten by binman,
> > copy it to u-boot.img.backup.
> >
> >
> >
> >
> > diff --git a/Makefile b/Makefile
> > index 87f9fc786e..4cffa8a061 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -1112,6 +1112,7 @@ endef
> >   # Timestamp file to make sure that binman always runs
> >   .binman_stamp: $(INPUTS-y) FORCE
> >   ifeq ($(CONFIG_BINMAN),y)
> > +       cp u-boot.img u-boot.img.backup
> >          $(call if_changed,binman)
> >   endif
> >          @touch $@
> >
> >
> >
> > Then, build it for the main core.
> >
> >
> > make -j$(nproc) CROSS_COMPILE=aarch64-linux-gnu-
> >     am64x_evm_a53_defconfig all
> >     TEE=~/ref/OP-TEE/optee_os/out/arm-plat-k3/core/tee-raw.bin
> >     BL31=~/ref/trusted-firmware-a/build/k3/lite/release/bl31.bin
> >     BINMAN_INDIRS=~/ref/ti-linux-firmware
> >
> >
> >
> >
> > Compare the two files.
> > Run fdtdump to see what happened to them.
> >
> >
> > $ diff -u u-boot.img  u-boot.img.backup
> > Binary files u-boot.img and u-boot.img.backup differ
> >
> >
> > $ fdtdump u-boot.img
> >      => u-boot and dt are embedded.
> >
> > $ fdtdump u-boot.img.backup
> >      => u-boot and dt are appended after the
> >         FIT structure
> >
> >
> >
>
> --
> Thanking You
> Neha Malcom Francis



-- 
Best Regards
Masahiro Yamada