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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Tue, 7 Sep 2021 16:11:50 +0200
Message-ID: <CAK8P3a0y0PhmOdMPnx10zG6s6RfiuC9Ju9s5SMnOk8oZ+cAFMw@mail.gmail.com>
Subject: Re: [PATCH v2 4/5] ARM: Add basic support for Airoha EN7523 SoC
To:     Daniel Palmer <daniel@0x0f.com>
Cc:     Arnd Bergmann <arnd@arndb.de>, Bert Vermeulen <bert@biot.com>,
        Russell King <linux@armlinux.org.uk>,
        Linus Walleij <linus.walleij@linaro.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Anshuman Khandual <anshuman.khandual@arm.com>,
        Marc Zyngier <maz@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        John Crispin <john@phrozen.org>,
        Ard Biesheuvel <ardb@kernel.org>,
        YiFei Zhu <yifeifz2@illinois.edu>,
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        <u.kleine-koenig@pengutronix.de>, Mike Rapoport <rppt@kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
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On Tue, Sep 7, 2021 at 2:27 PM Daniel Palmer <daniel@0x0f.com> wrote:
> On Tue, 7 Sept 2021 at 20:52, Arnd Bergmann <arnd@arndb.de> wrote:
> > > 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.
>
> I wonder how fixable it would be..
>
> I haven't gotten a board with the chip in question (SSD268G) yet but
> from looking at some firmware binaries I can see that even u-boot is a
> 6 year old 32bit version.
> As far as I can tell there's no PSCI, ATF etc that I think would be
> expected for an arm64 machine.

If the source code is available, creating a minimal PSCI implementation
in u-boot should be possible, and it would make it work well for both
32-bit and 64-bit kernels. There is no need for ATF here.

> I think the broken memory controller is still there so somehow I'd
> need to get the heavy barrier to work in arm64. I haven't yet worked
> out if that's even possible.

I think I missed that part of the discussion, or I forgot about it already.
What is the issue you are referring to here?

       Arnd