Document dedicated L2 Krait CPU Cache devfreq scaling driver. Signed-off-by: Ansuel Smith <ansuelsmth@xxxxxxxxx> --- v2: * Fix problems reported by Rob * Update example to use opp v2 * Drop unused voltage-tollerance * Better describe scaling thresholds * Add bindings to describe Krait L2-Cache .../bindings/arm/qcom,krait-cache.yaml | 116 ++++++++++++++++++ 1 file changed, 116 insertions(+) create mode 100644 Documentation/devicetree/bindings/arm/qcom,krait-cache.yaml diff --git a/Documentation/devicetree/bindings/arm/qcom,krait-cache.yaml b/Documentation/devicetree/bindings/arm/qcom,krait-cache.yaml new file mode 100644 index 000000000000..4143a758dc28 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/qcom,krait-cache.yaml @@ -0,0 +1,116 @@ +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/qcom,krait-cache.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Krait L2 CPU Cache + +maintainers: + - Ansuel Smith <ansuelsmth@xxxxxxxxx> + +description: | + This describe all the needed bindings required by the Krait L2 CPU Cache. + + Describe what level is available for the shared cache connected to the + Krait Cpus, the qcom saw used for qcom spm and how the cache should be + scaled using operating-points and cpufreq thresholds. + The Krait L2 CPU Cache Scaling Driver scale the frequency and optionally + voltage when the Cpu Frequency is changed (using the cpufreq notifier). + + Cache is scaled with the max frequency across all CPU core and the Cache + frequency will scale based on the configured CpuFreq threshold in the dts. + (example: CPU 600000 kHz, L2 Cache will be scaled to 1000000000 Hz. + CPU 1100000 kHz, L2 Cache will be scaled to 1000000000 Hz. + CPU 1200000 KHz, L2 Cache will be scaled to 1200000000 Hz.) + + The CpuFreq thresholds can be set from a minimum of 3 bin (idle, nominal + and high) and upper but the Krait Cache supports only 3 operating points. + +properties: + compatible: + const: qcom,krait-cache + + cache-level: + const: 2 + + qcom,saw: + $ref: "/schemas/types.yaml#/definitions/phandle" + description: | + Specifies the SAW* node associated with this L2 Cache. + + Required for systems that have an "enable-method" property + value of "qcom,kpss-acc-v1" or "qcom,kpss-acc-v2" defined in + CPUs node. + + * arm/msm/qcom,saw2.txt + + clocks: + maxItems: 1 + + clock-names: + items: + - const: l2 + + qcom,l2-cpufreq: + description: | + Threshold used by the driver to scale the L2 cache. + If the max CPU Frequency is more than the set frequency, + the driver will transition to the next frequency bin. + Value is in kHz + $ref: /schemas/types.yaml#/definitions/uint32-array + minItems: 3 + items: + - description: idle + - description: nominal + - description: high + + l2-supply: + $ref: "/schemas/types.yaml#/definitions/phandle" + description: Phandle to the L2 regulator supply. + + operating-points-v2: true + +required: + - compatible + - cache-level + - qcom,saw + - clocks + - clock-names + - qcom,l2-cpufreq + +examples: + - | + L2: l2-cache { + compatible = "qcom,krait-cache"; + cache-level = <2>; + qcom,saw = <&saw_l2>; + + clocks = <&kraitcc 4>; + clock-names = "l2"; + l2-supply = <&smb208_s1a>; + qcom,l2-cpufreq = <384000 600000 1200000>; + operating-points-v2 = <&opp_table_l2>; + }; + + opp_table_l2: opp_table_l2 { + compatible = "operating-points-v2"; + + opp-384000000 { + opp-hz = /bits/ 64 <384000000>; + opp-microvolt = <1100000>; + clock-latency-ns = <100000>; + }; + + opp-1000000000 { + opp-hz = /bits/ 64 <1000000000>; + opp-microvolt = <1100000>; + clock-latency-ns = <100000>; + }; + + opp-1200000000 { + opp-hz = /bits/ 64 <1200000000>; + opp-microvolt = <1150000>; + clock-latency-ns = <100000>; + }; + }; -- 2.27.0
