[RFC PATCH v2 1/7] ARM: zte: Add zx297520v3 platform support.

[Linus Walleij]

Hi Stefan,

thanks for your patch!

On Wed, Jan 28, 2026 at 9:35 PM Stefan Dösinger
<stefandoesinger at gmail.com> wrote:

> This SoC is used in low end LTE-to-WiFi routers, for example some D-Link
> DWR 932 revisions, ZTE K10, ZLT S10 4G, but also models that are branded
> and sold by ISPs themselves. They are widespread in Africa, China,
> Russia and Eastern Europe.
>
> This SoC is a relative of the zx296702 and zx296718 that had some
> upstream support until commit 89d4f98ae90d ("ARM: remove zte zx
> platform"). My eventual goal is to enable OpenWRT to run on these
> devices.

This is a noble goal.

> +Zx297520v3 SoCs use a 64 bit capable Cortex-A53 CPU and GICv3, although they
> +run in aarch32 mode only. The CPU has support EL3, but no hypervisor (EL2) and
> +it seems to lack VFP and NEON.

The practice to run 32bit kernels on 64bit capable hardware has been
pushed back in the past. When you say "they run aarch32 mode only" this
sounds like a choice, not a mandatory demand from the hardware, i.e.
it *could* run in 64bit mode.

We can see why the vendor does this because the board has only 64MB
of memory, and 64bit code is known to take up more memory.

What we recommend is usually to run a 64bit kernel with a 32bit userspace,
so the userspace still isn't too demanding in memory.

Have you been able to try this?

If it seems hard we might need to bring people in who can help with
enabling 64bit mode for the kernel.

I think Arnd might have pointers to previous conversations on the topic.

Yours,
Linus Walleij