From mboxrd@z Thu Jan  1 00:00:00 1970
From: mark.rutland@arm.com (Mark Rutland)
Date: Wed, 12 Feb 2014 11:29:46 +0000
Subject: [PATCH 1/3] arm64: dts: add initial dts for Samsung GH7 SoC
 and SSDK-GH7 board
In-Reply-To: <52FB575F.3070104@arm.com>
References: <1392100183-30930-1-git-send-email-kgene.kim@samsung.com>
 <1392100183-30930-2-git-send-email-kgene.kim@samsung.com>
 <CAOesGMjE=zOStKoZQhYLhYtL_aWD73DcF4w6STboZPMfHkLtxA@mail.gmail.com>
 <52FB575F.3070104@arm.com>
Message-ID: <20140212112946.GD21992@e106331-lin.cambridge.arm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

> >> +       gic: interrupt-controller at 1C000000 {
> >> +               compatible = "arm,cortex-a15-gic", "arm,cortex-a9-gic";
> > 
> > This looks incorrect -- you should at the very least have a more
> > specific one than a15-gic? Marc?
> 
> "arm,cortex-a9-gic" is definitely wrong (the A9 GIC doesn't have the
> virt extensions). This binding matches what the A15 GIC has, so
> "arm,cortex-a15-gic" is probably fine. Main issue here is that the GICv2
> driver has no compatible string for anything else.
> 
> Should we define something more generic (like "arm,gic-v2")? Or carry on
> adding more compatible strings?

It's been proposed repeatedly, and it probably makes sense to add the
generic versions to the driver, and allow for more specific ones in the
binding which DTs can use. That way we don't get an explosion of strings
in the driver, but if we need to handle any particular GIC specially in
future we can do so.

I guess for Linux we'd want to add "arm,gic-v1" and "arm,gic-v2" to the
driver. We could just add "arm,gic-v1" and expect it later in the
compatible list if v2 is a strict superset of v1; I think it is but I'm
not a GIC expert.

Thanks,
Mark.