[U-Boot] [linux-sunxi] Announcing easy Linux installation on Allwinner devices for non-geek users

[Maxime Ripard]

Hi,

Nice work overall, it's good to see something like that happening.

I'm a bit bothered by the use of the "universal" word, for something
that is so restricted, but it's just words.

On Thu, Jan 22, 2015 at 02:49:03PM +0200, Siarhei Siamashka wrote:
> =====================================================================
> == 5. Support more devices!
> =====================================================================
> 
> The number of supported Allwinner devices in u-boot v2015.01 is
> really small. A few more devices are being added for v2015.04
> While the progress is steady, I'm not convinced that the support
> for all the 100+ Allwinner devices can be added in a reasonable
> time frame.
> 
> The owners of some these devices are non-geeks and will not be able
> to submit patches to u-boot and the linux kernel on their own, even
> if provided with detailed instructions. This process just does not
> scale. Moreover, it is not very nice to force the users to master
> a useless skill, such as FEX knowledge.
> 
> So I see the automatic conversion as the only reasonable solution.
> 
> Yes, something like this already supposedly exits:
>     https://github.com/mripard/sunxi-babelfish

The point of babelfish has never been to be able to add support to
u-boot. The point was to be able to boot a mainline kernel on a legacy
bootloader, without having to change anything at the bootloader level
(be it the bootloader itself, or the environment), while not having to
really care about the state of the support of the device itself in
Linux.

> I don't know how much progress has the 'sunxi-babelfish' project
> made so far (and to be honest, even did not try it).

Not very far I must admit. AFAIK, no one ever ran it beside me, and
I'm not the target user. Patches are very welcome though.

> But in my opinion it has some fatal deficiencies in the design,
> based on just reading its README:
>   1. Implemented in the C language, while scripting languages are
>      orders of magnitude more suitable for such task and allow much
>      faster development.

Let me know how you can fake a zImage and run bare metal code in ruby,
I'm interested.

>   2. This approach does not look very testable/debuggable.

It's true that some debug output might be needed. Patches welcome,
again.

>   3. It apparently does not help mainlining. The output of the
>      conversion does not look like it is intended to be used as a
>      template for the DTS file submission to the mainline kernel.

It really is. DTC can output a DTS from a running kernel, by looking
at /proc/device-tree. That DTS can totaly be used as a base to submit
it.

> So the right solution in my opinion is a set of scripts for the
> sunxi-boards repository. The scripts need to parse the FEX files,
> which are conveniently already collected in sunxi-boards. They
> need to support different FEX dialects as input (this is really
> important!) and 3 types of output:
>   1. The defconfigs for u-boot
>   2. The DTS files for the linux kernel
>   3. The FEX file in a dialect, which is compatible with the sunxi-3.4
>      kernel

Just so you know, I will *not* merge any patch automatically generated
that will not have been run on its real board.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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