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From:   Daniel Palmer <daniel@0x0f.com>
Date:   Wed, 2 Dec 2020 18:10:43 +0900
Message-ID: <CAFr9PXnME5UCyOdkRGFO2+=gv27grcq35Adrtio3ex4hq0CWEQ@mail.gmail.com>
Subject: Re: [PATCH v2 10/10] ARM: mstar: SMP support
To:     Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc:     DTML <devicetree@vger.kernel.org>, SoC Team <soc@kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        olof@lixom.net, Arnd Bergmann <arnd@arndb.de>,
        Rob Herring <robh@kernel.org>, Willy Tarreau <w@1wt.eu>
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Hi Russell,

On Wed, 2 Dec 2020 at 00:04, Russell King - ARM Linux admin
<linux@armlinux.org.uk> wrote:
>
> On Tue, Dec 01, 2020 at 10:43:30PM +0900, Daniel Palmer wrote:
> > +     np = of_find_compatible_node(NULL, NULL, "mstar,smpctrl");
> > +     smpctrl = of_iomap(np, 0);
> > +
> > +     if (!smpctrl)
> > +             return -ENODEV;
>
> Wouldn't -ENOMEM be more appropriate here?

There seems to be examples of both -ENOMEM and -ENODEV in other ARM platforms.
arch/arm/mach-aspeed/platsmp.c uses -ENODEV for example.

I went with -ENODEV there as the source of the error is most likely
the node not being in the device tree.
I didn't check the result of of_find_compatible_node() because for the
memory barrier code in the same file I was told it wasn't necessary.

Thanks,

Daniel