On Sun, 28 Apr 2024 13:40:36 +0200
Dragan Simic <dsimic@xxxxxxxxxxx> wrote:
Add missing cache information to the Allwinner H6 SoC dtsi, to allow
the userspace, which includes lscpu(1) that uses the virtual files provided
by the kernel under the /sys/devices/system/cpu directory, to display the
proper H6 cache information.
Adding the cache information to the H6 SoC dtsi also makes the following
warning message in the kernel log go away:
cacheinfo: Unable to detect cache hierarchy for CPU 0
The cache parameters for the H6 dtsi were obtained and partially derived
by hand from the cache size and layout specifications found in the following
datasheets and technical reference manuals:
- Allwinner H6 V200 datasheet, version 1.1
- ARM Cortex-A53 revision r0p3 TRM, version E
For future reference, here's a brief summary of the documentation:
- All caches employ the 64-byte cache line length
- Each Cortex-A53 core has 32 KB of L1 2-way, set-associative instruction
cache and 32 KB of L1 4-way, set-associative data cache
- The entire SoC has 512 KB of unified L2 16-way, set-associative cache
Signed-off-by: Dragan Simic <dsimic@xxxxxxxxxxx>
I can confirm that the data below matches the manuals, but also the
decoding of the architectural cache type registers (CCSIDR_EL1):
L1D: 32 KB: 128 sets, 4 way associative, 64 bytes/line
L1I: 32 KB: 256 sets, 2 way associative, 64 bytes/line
L2: 512 KB: 512 sets, 16 way associative, 64 bytes/line
tinymembench results for the H6 are available here:
https://github.com/ThomasKaiser/sbc-bench/blob/master/results/26Ph.txt
and confirm the theory. Also ran it locally with similar results.
Reviewed-by: Andre Przywara <andre.przywara@xxxxxxx>
---
arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi | 37 ++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi
index d11e5041bae9..1a63066396e8 100644
--- a/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi
+++ b/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi
@@ -29,36 +29,73 @@ cpu0: cpu@0 {
clocks = <&ccu CLK_CPUX>;
clock-latency-ns = <244144>; /* 8 32k periods */
#cooling-cells = <2>;
+ i-cache-size = <0x8000>;
+ i-cache-line-size = <64>;
+ i-cache-sets = <256>;
+ d-cache-size = <0x8000>;
+ d-cache-line-size = <64>;
+ d-cache-sets = <128>;
+ next-level-cache = <&l2_cache>;
};
cpu1: cpu@1 {
compatible = "arm,cortex-a53";
device_type = "cpu";
reg = <1>;
enable-method = "psci";
clocks = <&ccu CLK_CPUX>;
clock-latency-ns = <244144>; /* 8 32k periods */
#cooling-cells = <2>;
+ i-cache-size = <0x8000>;
+ i-cache-line-size = <64>;
+ i-cache-sets = <256>;
+ d-cache-size = <0x8000>;
+ d-cache-line-size = <64>;
+ d-cache-sets = <128>;
+ next-level-cache = <&l2_cache>;
};
cpu2: cpu@2 {
compatible = "arm,cortex-a53";
device_type = "cpu";
reg = <2>;
enable-method = "psci";
clocks = <&ccu CLK_CPUX>;
clock-latency-ns = <244144>; /* 8 32k periods */
#cooling-cells = <2>;
+ i-cache-size = <0x8000>;
+ i-cache-line-size = <64>;
+ i-cache-sets = <256>;
+ d-cache-size = <0x8000>;
+ d-cache-line-size = <64>;
+ d-cache-sets = <128>;
+ next-level-cache = <&l2_cache>;
};
cpu3: cpu@3 {
compatible = "arm,cortex-a53";
device_type = "cpu";
reg = <3>;
enable-method = "psci";
clocks = <&ccu CLK_CPUX>;
clock-latency-ns = <244144>; /* 8 32k periods */
#cooling-cells = <2>;
+ i-cache-size = <0x8000>;
+ i-cache-line-size = <64>;
+ i-cache-sets = <256>;
+ d-cache-size = <0x8000>;
+ d-cache-line-size = <64>;
+ d-cache-sets = <128>;
+ next-level-cache = <&l2_cache>;
+ };
+
+ l2_cache: l2-cache {
+ compatible = "cache";
+ cache-level = <2>;
+ cache-unified;
+ cache-size = <0x80000>;
+ cache-line-size = <64>;
+ cache-sets = <512>;
};
};