Re: [PATCH v2 4/5] ARM: Add basic support for Airoha EN7523 SoC

On Tue, Sep 7, 2021 at 12:48 PM Daniel Palmer [off-list ref] wrote:

On Tue, 7 Sept 2021 at 19:30, Bert Vermeulen [off-list ref] wrote:

quoted

From: John Crispin <john@phrozen.org>

EN7523 is an armv7 based silicon used inside broadband access type devices
such as xPON and xDSL. It shares various silicon blocks with MediaTek
silicon such as the MT7622.

This is a Cortex A53 isn't it? So it's ARMv8. I thought the issue is
that it's actually a 64bit system but you only have a 32bit
bootloader, firmware etc?

Off-topic but related:  Another MediaTek spin off, SigmaStar, seems to
have done exactly the same thing. Cortex A53 chip running as a 32bit
system to avoid having to fix their software. I'm interested to see if
this makes it into arm or arm64. :)

Maybe it's best to just add them to both at the same time? The boot
loader situation might take a bit to work out, but in theory this should
be fixable.

You can generally include .dtsi files from one in the other, as you can
see from e.g. arch/arm64/boot/dts/broadcom/bcm2837-rpi-3-b.dts.

For new files, I think I would prefer having the .dts files in arm64 and
including them from arch/arm/ rather than the other way round, but
others may come up with a good reason to keep doing the reverse.
This would help encourage the thought that running a 64-bit
kernel is the better setup, rather than propagate the 32-bit kernel
nonsense on 64-bit machines.

       Arnd

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