arm64: dts: mediatek: mt8192: Fix CPUs capacity-dmips-mhz

The capacity-dmips-mhz parameter was miscalculated: this SoC runs
the first (Cortex-A55) cluster at a maximum of 2000MHz and the
second (Cortex-A76) cluster at a maximum of 2200MHz.

In order to calculate the right capacity-dmips-mhz, the following
test was performed:
1. CPUFREQ governor was set to 'performance' on both clusters
2. Ran dhrystone with 500000000 iterations for 10 times on each cluster
3. Calculated the mean result for each cluster
4. Calculated DMIPS/MHz: dmips_mhz = dmips_per_second / cpu_mhz
5. Scaled results to 1024:
   result_c0 = dmips_mhz_c0 / dmips_mhz_c1 * 1024

The mean results for this SoC are:
Cluster 0 (LITTLE): 12016411 Dhry/s
Cluster 1 (BIG): 31702034 Dhry/s

The calculated scaled results are:
Cluster 0: 426.953226899238 (rounded to 427)
Cluster 1: 1024

Fixes: 48489980e27e ("arm64: dts: Add Mediatek SoC MT8192 and evaluation board dts and Makefile")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20230602183515.3778780-1-nfraprado@collabora.com
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

diff --git a/arch/arm64/boot/dts/mediatek/mt8192.dtsi b/arch/arm64/boot/dts/mediatek/mt8192.dtsi
index bab403a43c4d81b66225439f5c29adb565058e6f..69f4cded5dbbf2112c082378b9018b5e7dbec1d2 100644 (file)
--- a/arch/arm64/boot/dts/mediatek/mt8192.dtsi
+++ b/arch/arm64/boot/dts/mediatek/mt8192.dtsi
@@ -71,7 +71,7 @@ cpu0: cpu@0 {
                        d-cache-sets = <128>;
                        next-level-cache = <&l2_0>;
                        performance-domains = <&performance 0>;
-                       capacity-dmips-mhz = <530>;
+                       capacity-dmips-mhz = <427>;
                };
 
                cpu1: cpu@100 {
@@ -89,7 +89,7 @@ cpu1: cpu@100 {
                        d-cache-sets = <128>;
                        next-level-cache = <&l2_0>;
                        performance-domains = <&performance 0>;
-                       capacity-dmips-mhz = <530>;
+                       capacity-dmips-mhz = <427>;
                };
 
                cpu2: cpu@200 {
@@ -107,7 +107,7 @@ cpu2: cpu@200 {
                        d-cache-sets = <128>;
                        next-level-cache = <&l2_0>;
                        performance-domains = <&performance 0>;
-                       capacity-dmips-mhz = <530>;
+                       capacity-dmips-mhz = <427>;
                };
 
                cpu3: cpu@300 {
@@ -125,7 +125,7 @@ cpu3: cpu@300 {
                        d-cache-sets = <128>;
                        next-level-cache = <&l2_0>;
                        performance-domains = <&performance 0>;
-                       capacity-dmips-mhz = <530>;
+                       capacity-dmips-mhz = <427>;
                };
 
                cpu4: cpu@400 {