[Letux-kernel] Raspi3B+ support

H. Nikolaus Schaller hns at goldelico.com
Sat Jan 5 20:56:25 CET 2019


Hi,

> Am 05.01.2019 um 19:48 schrieb Andreas Kemnade <andreas at kemnade.info>:
> 
> Hi,
> 
> On Sat, 5 Jan 2019 08:21:40 +0100
> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
> 
>> Hi Andreas,
>> 
>>> Am 04.01.2019 um 20:27 schrieb Andreas Kemnade <andreas at kemnade.info>:
>>> 
>>> Hi,
>>> 
>>> On Fri, 4 Jan 2019 14:45:47 +0100
>>> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
>>> 
>>>> Hi,
>>>> with help and suggestions from Mark, I finally managed
>>>> to get our Letux kernel compile and boot on the Raspi3B+.
>>>> 
>>> Do you add -@ to DTC_FLAGS to make handling dtb overlays easier?  
>> 
>> You mean something like:
>> 
>> https://github.com/beagleboard/meta-beagleboard/blob/master/common-bsp/recipes-kernel/linux/linux-mainline-3.8/not-capebus/0021-OF-Compile-Device-Tree-sources-with-resolve-option.patch
>> 
> yes.
> 
>> No, since mainline kernel seems not to build or need any overlays
>> for RasPi and I am not (yet) aiming at shield/hat/capes. Just a "PC"
>> like setup (monitor, keyboard, LAN).
>> 
> Hmm, for a PC-like setup I would choose a standard debian.

Well, for me LetuxOS is the standard Debian for everything :)

The main goal is that I know what is in the kernel and how to install
special things.

For default Debian every board has its own installer...

> For a
> RasPi with e.g. touchscreen hat I would be happy to just use a letux
> system. And remember, someone presented a raspi phone at Fosdem in that
> restaurant.

Yes, that was Arsenijs: https://zerophone.github.io/newsletter/

Maybe we can add something for a touchscreen or the zerophone later.
At the moment it is enough trouble to get it working at all without any
extensions...

> The bottom line of the discussion about that on LKML is that enabling
> symbols for all dtb files is not wanted but to enable it on request for
> individual files. You can set flags per file.
> 
> The usually used bootloader configs for these shield/hat capable boards
> look in directories for overlays. So maybe it would be a good idea to
> enable it so that people simply can copy in their overlays from other
> sources into a letux system without touching the kernel. Well
> to some extent, overlays are also working without symbols.

I have also found that the github tree has an arch/arm/boot/dts/overlays
subdirectory with a Makefile that depends on CONFIG_ARCH_BCM2835.

This does not exist at all in mainline (v4.20). Which means an upstream
kernel should work well without overlays. If it works...

Generally I expect that this discussion will continue on LKML and
maybe with v4.25 they have a solution that covers all hats/capes/shields etc.
for all SBCs since BeagleBoard/Bone have the same needs... So it will
come without us having to do too much.

BR,
Nikolaus



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