linux-kernel - Re: [RFC 2/7] ARM: dts: sun9i: Add CCI-400 device nodes for A80

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Date:	Sun, 17 May 2015 16:51:46 +0200
From:	Maxime Ripard <maxime.ripard@...e-electrons.com>
To:	Chen-Yu Tsai <wens@...e.org>
Cc:	Nicolas Pitre <nicolas.pitre@...aro.org>,
	Dave Martin <Dave.Martin@....com>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-sunxi@...glegroups.com
Subject: Re: [RFC 2/7] ARM: dts: sun9i: Add CCI-400 device nodes for A80

On Thu, May 14, 2015 at 02:10:06PM +0800, Chen-Yu Tsai wrote:
> The A80 includes an ARM CCI-400 interconnect to support multi-cluster
> CPU caches.
> 
> Also add the default clock frequency for the CPUs.
> 
> Signed-off-by: Chen-Yu Tsai <wens@...e.org>
> ---
>  arch/arm/boot/dts/sun9i-a80.dtsi | 46 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 46 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/sun9i-a80.dtsi b/arch/arm/boot/dts/sun9i-a80.dtsi
> index ca272e92b85d..200e712fbf0e 100644
> --- a/arch/arm/boot/dts/sun9i-a80.dtsi
> +++ b/arch/arm/boot/dts/sun9i-a80.dtsi
> @@ -58,48 +58,64 @@
>  		cpu0: cpu@0 {
>  			compatible = "arm,cortex-a7";
>  			device_type = "cpu";
> +			cci-control-port = <&cci_control0>;
> +			clock-frequency = <12000000>;
>  			reg = <0x0>;
>  		};
>  
>  		cpu1: cpu@1 {
>  			compatible = "arm,cortex-a7";
>  			device_type = "cpu";
> +			cci-control-port = <&cci_control0>;
> +			clock-frequency = <12000000>;
>  			reg = <0x1>;
>  		};
>  
>  		cpu2: cpu@2 {
>  			compatible = "arm,cortex-a7";
>  			device_type = "cpu";
> +			cci-control-port = <&cci_control0>;
> +			clock-frequency = <12000000>;
>  			reg = <0x2>;
>  		};
>  
>  		cpu3: cpu@3 {
>  			compatible = "arm,cortex-a7";
>  			device_type = "cpu";
> +			cci-control-port = <&cci_control0>;
> +			clock-frequency = <12000000>;
>  			reg = <0x3>;
>  		};
>  
>  		cpu4: cpu@100 {
>  			compatible = "arm,cortex-a15";
>  			device_type = "cpu";
> +			cci-control-port = <&cci_control1>;
> +			clock-frequency = <9000000>;

Isn't the clock frequency property is supposed to be the maximum
frequency of that CPU in Linux?

It looks odd that the A15 are clocked at a lower frequency than the
A7...

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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