[PATCH] bmips: Add Inteno XG6846 board

[Daniel Schwierzeck]

On 9/20/23 20:55, Tom Rini wrote:
> On Wed, Sep 20, 2023 at 08:51:07PM +0200, Linus Walleij wrote:
>> On Wed, Sep 20, 2023 at 4:22 PM Tom Rini <trini at konsulko.com> wrote:
>>
>>>> + * This is a diet version of the device tree from Linux,
>>>> + * suitable for U-Boot.
>>>> + */
>>>
>>> We shouldn't need a diet version of the tree.  If it's reasonably done
>>> and stable in the kernel, we can even move towards just passing the
>>> U-Boot tree along to Linux.
>>
>> The device tree is not stable in the kernel.
>> It exists in OpenWrt and the creators of the bmips target are
>> kind of absent for the moment. The reason it is not in Linux
>> is that the "switch ethernet" driver and bindings need to be
>> upstreamed before the device trees can be upstreamed.
>>
>> But I can try to bring in more of it for sure :)
> 
> Just like ARM the goal is just to drop in the kernel dts here.

I guess this approach works well for ARM but not for MIPS. Most MIPS consumer boards
are just maintained in OpenWRT but not in mainline Linux. And there are a few boards
which have been just mainlined in U-Boot but not Linux so them also don't have a
stable Linux DT.

As MIPS is a dead architecture I suggest to just go with the minimal DT suited for U-Boot ;)

> 
>>>> +++ b/board/inteno/xg6846/xg6846.c
>>>> @@ -0,0 +1,6 @@
>>>> +// SPDX-License-Identifier: GPL-2.0+
>>>> +/*
>>>> + * Copyright (C) 2023 Linus Walleij <linusw at kernel.org>
>>>> + */
>>>> +
>>>> +#include <common.h>
>>>
>>> So basically just an empty object file.  Can we just _not_ have
>>> something here, if we perhaps don't set SYS_BOARD?  I assume if there's
>>> just nothing here the link rules fail.
>>
>> Admittedly my knowledge of U-Boot internals are not the
>> best and this is a bit of a copy and paste job from
>> board/comtrend/ar5387un/ar-5387un.c which looks like
>> this and sets a bad example I suppose.
> 
> Yeah, I didn't know we had someone doing that already here, whoops.
> 
>> I guess you are asking me to modify U-Boots build system to
>> make the whole .c and Makefile inside a board subdir optional
>> so we can delete all such empty boardfiles?
> 
> Well, it'd sure be nice if we could avoid having a dummy C file.  If
> it looks like a nightmare once you take a peek, we can just live with
> it.
> 

I just tested it, you can simply add an empty board/inteno/xg6846/Makefile and
remove board/inteno/xg6846/xg6846.c. But you can also remove the Makefile.
Just the Kconfig and MAINTAINERS file are needed.

-- 
- Daniel