[Letux-kernel] X1600 / LX16 support - here: compile issue

[Andreas Kemnade]

On Wed, 7 Feb 2024 15:05:40 +0100
"H. Nikolaus Schaller" <hns at goldelico.com> wrote:

> Hi Andreas,
> 
> > Am 07.02.2024 um 09:42 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
> > 
> > Ah,
> >   
> >> Am 07.02.2024 um 09:07 schrieb Andreas Kemnade <andreas at kemnade.info>:
> >> 
> >> Hi,
> >> 
> >> On Wed, 7 Feb 2024 08:36:58 +0100
> >> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
> >>   
> >>> make V=2 CONFIG_DEBUG_SECTION_MISMATCH=y letux_lx16_defconfig savedefconfig uImage dtbs LOADADDR=0x80008000  
> >> 
> >> and I did a make all (after make zImage not working), I did not try uImage (which works).
> >> 
> >> Lets hope the kernel ci bots do the same... But ci120_defconfig works also with "all".  
> > 
> > as usual the solution is simple - as soon as you know it...
> > 
> > So I can try to reproduce with "all" and compare with other gcc versions.  
> 
> Yes, I can now reproduce with "all" and gcc 6.3.0. And even with letux_ci20_defconfig.
> 
> So likely we have disabled/deconfigured something which is needed for "all" to build "its"/"itb".
> 
Then there are dependencies missing in Kconfig that should such a Kconfig from existing.
Well, we have "make randconfig" and any config generated should at least compile as it is
used by bots.

We have
CONFIG_BUILTIN_DTB=y
CONFIG_MIPS_NO_APPENDED_DTB=y
# CONFIG_MIPS_ELF_APPENDED_DTB is not set
# CONFIG_MIPS_RAW_APPENDED_DTB is not set

So if DTB is somehow builtin and not appended, I guess it is a strong indication that we
want to use the FIT stuff and by calling make uImage we are gaming the system a bit?
Not sure yet, if I really understand it now.

But just to not stumble about a subtle thing again: Where does the dtb end
up now and how it goes to the kernel?

> arch/mips//boot/compressed/Makefile tells that this is Flattened Image Tree (.itb) image.
> 
> Here I found a good description what it is:
> 
> https://www.thegoodpenguin.co.uk/blog/u-boot-fit-image-overview/
> 
> But to be honest, I do not see any benefits for the Letux projects...
> 
> Except for the fw_getenv() issue, the U-Boot can be stable for years.
> So there is no need to pack it together with kernel images which change
> every week.

Hmm, FIT does not necessarily package u-boot. I think we were talking
about FIT earlier because of falcon boot mode in uboot skipping most
stuff there.
> 
> And for ARM we have a single uImage for all. Multiplying this with the
> number of boards (each having a different U-Boot setup) we support, would
> just add a lot of bytes to the download server.

Yes, I doubt FIT will be useful unless accompanied by a proper process.
I personally use raw zImage /vmlinuz everywhere. bootz was invented. And
modern u-boot can even use some extlinux files, so no uboot-specific
kernel installation care on distro side needed.
> 

Regards,
Andreas