arm64: dts: rockchip: Move L3 cache under CPUs in RK356x SoC dtsi

[PATCH] arm64: dts: rockchip: Move L3 cache under CPUs in RK356x SoC dtsi

Posted by Dragan Simic 1 year, 4 months ago

Move the "l3_cache" node under the "cpus" node in the dtsi file for Rockchip
RK356x SoCs.  There's no need for this cache node to be at the higher level.

Fixes: 8612169a05c5 ("arm64: dts: rockchip: Add cache information to the SoC dtsi for RK356x")
Cc: stable@vger.kernel.org
Signed-off-by: Dragan Simic <dsimic@manjaro.org>
---
 arch/arm64/boot/dts/rockchip/rk356x.dtsi | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/boot/dts/rockchip/rk356x.dtsi b/arch/arm64/boot/dts/rockchip/rk356x.dtsi
index 4690be841a1c..9f7136e5d553 100644
--- a/arch/arm64/boot/dts/rockchip/rk356x.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk356x.dtsi
@@ -113,19 +113,19 @@ cpu3: cpu@300 {
 			d-cache-sets = <128>;
 			next-level-cache = <&l3_cache>;
 		};
-	};
 
-	/*
-	 * There are no private per-core L2 caches, but only the
-	 * L3 cache that appears to the CPU cores as L2 caches
-	 */
-	l3_cache: l3-cache {
-		compatible = "cache";
-		cache-level = <2>;
-		cache-unified;
-		cache-size = <0x80000>;
-		cache-line-size = <64>;
-		cache-sets = <512>;
+		/*
+		 * There are no private per-core L2 caches, but only the
+		 * L3 cache that appears to the CPU cores as L2 caches
+		 */
+		l3_cache: l3-cache {
+			compatible = "cache";
+			cache-level = <2>;
+			cache-unified;
+			cache-size = <0x80000>;
+			cache-line-size = <64>;
+			cache-sets = <512>;
+		};
 	};
 
 	cpu0_opp_table: opp-table-0 {

Re: [PATCH] arm64: dts: rockchip: Move L3 cache under CPUs in RK356x SoC dtsi

Posted by Robin Murphy 1 year, 4 months ago

On 2024-09-26 8:49 am, Dragan Simic wrote:
> Move the "l3_cache" node under the "cpus" node in the dtsi file for Rockchip
> RK356x SoCs.  There's no need for this cache node to be at the higher level.

Except it does arguably represent the physical topology - the L3 cache 
doesn't belong to the CPUs, it belongs to the DSU, which very much is 
"outside" the CPUs.

Thanks,
Robin.

> 
> Fixes: 8612169a05c5 ("arm64: dts: rockchip: Add cache information to the SoC dtsi for RK356x")
> Cc: stable@vger.kernel.org
> Signed-off-by: Dragan Simic <dsimic@manjaro.org>
> ---
>   arch/arm64/boot/dts/rockchip/rk356x.dtsi | 24 ++++++++++++------------
>   1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/rockchip/rk356x.dtsi b/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> index 4690be841a1c..9f7136e5d553 100644
> --- a/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> @@ -113,19 +113,19 @@ cpu3: cpu@300 {
>   			d-cache-sets = <128>;
>   			next-level-cache = <&l3_cache>;
>   		};
> -	};
>   
> -	/*
> -	 * There are no private per-core L2 caches, but only the
> -	 * L3 cache that appears to the CPU cores as L2 caches
> -	 */
> -	l3_cache: l3-cache {
> -		compatible = "cache";
> -		cache-level = <2>;
> -		cache-unified;
> -		cache-size = <0x80000>;
> -		cache-line-size = <64>;
> -		cache-sets = <512>;
> +		/*
> +		 * There are no private per-core L2 caches, but only the
> +		 * L3 cache that appears to the CPU cores as L2 caches
> +		 */
> +		l3_cache: l3-cache {
> +			compatible = "cache";
> +			cache-level = <2>;
> +			cache-unified;
> +			cache-size = <0x80000>;
> +			cache-line-size = <64>;
> +			cache-sets = <512>;
> +		};
>   	};
>   
>   	cpu0_opp_table: opp-table-0 {
> 
> _______________________________________________
> Linux-rockchip mailing list
> Linux-rockchip@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-rockchip

Re: [PATCH] arm64: dts: rockchip: Move L3 cache under CPUs in RK356x SoC dtsi

Posted by Dragan Simic 1 year, 4 months ago

Hello Robin,

On 2024-09-26 11:24, Robin Murphy wrote:
> On 2024-09-26 8:49 am, Dragan Simic wrote:
>> Move the "l3_cache" node under the "cpus" node in the dtsi file for 
>> Rockchip
>> RK356x SoCs.  There's no need for this cache node to be at the higher 
>> level.
> 
> Except it does arguably represent the physical topology - the L3 cache
> doesn't belong to the CPUs, it belongs to the DSU, which very much is
> "outside" the CPUs.

That's a very good point, thanks!  I knew there must have been
a very good reason why I placed the L3 cache outside the CPUs
originally, in the commit 8612169a05c5 referenced below, but I
also somehow managed to forget that reason for a moment. :)

Let's drop this patch, and I'll submit another patch for the
RK3588 SoC dtsi files that moves the L3 cache outside the CPUs,
to reflect the physical topology better.

>> Fixes: 8612169a05c5 ("arm64: dts: rockchip: Add cache information to 
>> the SoC dtsi for RK356x")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Dragan Simic <dsimic@manjaro.org>
>> ---
>>   arch/arm64/boot/dts/rockchip/rk356x.dtsi | 24 
>> ++++++++++++------------
>>   1 file changed, 12 insertions(+), 12 deletions(-)
>> 
>> diff --git a/arch/arm64/boot/dts/rockchip/rk356x.dtsi 
>> b/arch/arm64/boot/dts/rockchip/rk356x.dtsi
>> index 4690be841a1c..9f7136e5d553 100644
>> --- a/arch/arm64/boot/dts/rockchip/rk356x.dtsi
>> +++ b/arch/arm64/boot/dts/rockchip/rk356x.dtsi
>> @@ -113,19 +113,19 @@ cpu3: cpu@300 {
>>   			d-cache-sets = <128>;
>>   			next-level-cache = <&l3_cache>;
>>   		};
>> -	};
>>   -	/*
>> -	 * There are no private per-core L2 caches, but only the
>> -	 * L3 cache that appears to the CPU cores as L2 caches
>> -	 */
>> -	l3_cache: l3-cache {
>> -		compatible = "cache";
>> -		cache-level = <2>;
>> -		cache-unified;
>> -		cache-size = <0x80000>;
>> -		cache-line-size = <64>;
>> -		cache-sets = <512>;
>> +		/*
>> +		 * There are no private per-core L2 caches, but only the
>> +		 * L3 cache that appears to the CPU cores as L2 caches
>> +		 */
>> +		l3_cache: l3-cache {
>> +			compatible = "cache";
>> +			cache-level = <2>;
>> +			cache-unified;
>> +			cache-size = <0x80000>;
>> +			cache-line-size = <64>;
>> +			cache-sets = <512>;
>> +		};
>>   	};
>>     	cpu0_opp_table: opp-table-0 {
>> 
>> _______________________________________________
>> Linux-rockchip mailing list
>> Linux-rockchip@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-rockchip
> 
> _______________________________________________
> Linux-rockchip mailing list
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> http://lists.infradead.org/mailman/listinfo/linux-rockchip