Re: [PATCH v2 1/2] dt-bindings: arm,gic: Fix binding example for a virt-capable GIC

From: Rob Herring <robh@kernel.org>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Jason Cooper" <jason@lakedaemon.net>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Tsahee Zidenberg" <tsahee@annapurnalabs.com>,
	"Antoine Tenart" <antoine.tenart@free-electrons.com>,
	"Russell King" <linux@armlinux.org.uk>,
	"Benoît Cousson" <bcousson@baylibre.com>,
	"Tony Lindgren" <tony@atomide.com>,
	"Kukjin Kim" <kgene@kernel.org>,
	"Krzysztof Kozlowski" <krzk@kernel.org>,
	"Javier Martinez Canillas" <javier@osg.samsung.com>,
	"Shawn Guo" <shawnguo@kernel.org>,
	"Sascha Hauer" <kernel@pengutronix.de>,
	"Fabio Estevam" <fabio.estevam@nxp.com>,
	"Santosh Shilimkar" <ssantosh@kernel.org>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"Simon Horman" <horms@verge.net.au>,
	"Magnus Damm" <magnus.damm@gmail.com>,
	"Heiko Stuebner" <heiko@sntech.de>,
	"Maxime Ripard" <maxime.ripard@free-electrons.com>,
	"Chen-Yu Tsai" <wens@csie.org>,
	arm@kernel.org
Subject: Re: [PATCH v2 1/2] dt-bindings: arm,gic: Fix binding example for a virt-capable GIC
Date: Fri, 27 Jan 2017 14:30:01 -0600	[thread overview]
Message-ID: <20170127203001.qvlgzzrh5hx2pykf@rob-hp-laptop> (raw)
In-Reply-To: <1485186974-13678-2-git-send-email-marc.zyngier@arm.com>

On Mon, Jan 23, 2017 at 03:56:13PM +0000, Marc Zyngier wrote:
> The joys of copy/paste: the example of a virtualization capable GIC
> in the DT binding was wrong, and propagated to dozens of platforms.
> By having a GICC region that is only 4kB (instead of 8kB), we
> end-up not being able to access the GICC_DIR register which is on
> the second page.
> 
> Oh well. Let's fix the source of the crap before tackling individual
> offenders. While we're at it, also fix the compatibility string to
> mention "arm,gic-400", which is the name of the actual implementation
> of the GICv2 spec.

"While we're at it", code for should be in a separate patch. :) I 
wouldn't really care here, but you are not fixing anything...

> 
> Acked-by: Tony Lindgren <tony@atomide.com>
> Acked-by: Mark Rutland <mark.rutland@arm.com>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  Documentation/devicetree/bindings/interrupt-controller/arm,gic.txt | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/interrupt-controller/arm,gic.txt b/Documentation/devicetree/bindings/interrupt-controller/arm,gic.txt
> index 5393e2a..a3d51ed 100644
> --- a/Documentation/devicetree/bindings/interrupt-controller/arm,gic.txt
> +++ b/Documentation/devicetree/bindings/interrupt-controller/arm,gic.txt
> @@ -107,11 +107,11 @@ Required properties:
>  Example:
>  
>  	interrupt-controller@2c001000 {
> -		compatible = "arm,cortex-a15-gic";
> +		compatible = "arm,gic-400";

Which one is correct really depends on the platform. The A15 can have an 
internal or external (gic-400) GIC. The former string is correct for an 
A15 with an internal GIC. One such platform is Calxeda midway.

Arguably, we should not have arm,gic-400 by itself, but have an SoC 
specific compatible in case it was integrated in interesting ways.

Rob