Documentation/devicetree/bindings/cpufreq/virtual,android-v-only-cpufreq.yaml

# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
%YAML 1.2
---
$id: http://devicetree.org/schemas/cpufreq/virtual,android-v-only-cpufreq.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Android-V-Only Virtual CPUFreq

maintainers:
  - David Dai <davidai@google.com>
  - Saravana Kannan <saravanak@google.com>

description:
  Android-V-Only Virtual CPUFreq is a virtualized driver in guest kernels that
  sends frequency selection of its vCPUs as a hint to the host through MMIO
  regions.  Each vCPU is associated with a frequency domain which can be shared
  with other vCPUs.  Each frequency domain has its own set of registers for
  frequency controls.

properties:
  compatible:
    const: virtual,android-v-only-cpufreq

  reg:
    maxItems: 1
    description:
      Address and size of region containing frequency controls for each of the
      frequency domains. Regions for each frequency domain is placed
      contiguously and contain registers for controlling DVFS(Dynamic Frequency
      and Voltage) characteristics. The size of the region is proportional to
      total number of frequency domains. This device also needs the CPUs to
      list their OPPs using operating-points-v2 tables. The OPP tables for the
      CPUs should use normalized "frequency" values where the OPP with the
      highest performance among all the vCPUs is listed as 1024 KHz. The rest
      of the frequencies of all the vCPUs should be normalized based on their
      performance relative to that 1024 KHz OPP. This makes it much easier to
      migrate the VM across systems which might have different physical CPU
      OPPs.

required:
  - compatible
  - reg

additionalProperties: false

examples:
  - |
    // This example shows a two CPU configuration with a frequency domain
    // for each CPU showing normalized performance points.
    cpus {
      #address-cells = <1>;
      #size-cells = <0>;

      cpu@0 {
        compatible = "arm,armv8";
        device_type = "cpu";
        reg = <0x0>;
        operating-points-v2 = <&opp_table0>;
      };

      cpu@1 {
        compatible = "arm,armv8";
        device_type = "cpu";
        reg = <0x0>;
        operating-points-v2 = <&opp_table1>;
      };
    };

    opp_table0: opp-table-0 {
      compatible = "operating-points-v2";

      opp64000 { opp-hz = /bits/ 64 <64000>; };
      opp128000 { opp-hz = /bits/ 64 <128000>; };
      opp192000 { opp-hz = /bits/ 64 <192000>; };
      opp256000 { opp-hz = /bits/ 64 <256000>; };
      opp320000 { opp-hz = /bits/ 64 <320000>; };
      opp384000 { opp-hz = /bits/ 64 <384000>; };
      opp425000 { opp-hz = /bits/ 64 <425000>; };
    };

    opp_table1: opp-table-1 {
      compatible = "operating-points-v2";

      opp64000 { opp-hz = /bits/ 64 <64000>; };
      opp128000 { opp-hz = /bits/ 64 <128000>; };
      opp192000 { opp-hz = /bits/ 64 <192000>; };
      opp256000 { opp-hz = /bits/ 64 <256000>; };
      opp320000 { opp-hz = /bits/ 64 <320000>; };
      opp384000 { opp-hz = /bits/ 64 <384000>; };
      opp448000 { opp-hz = /bits/ 64 <448000>; };
      opp512000 { opp-hz = /bits/ 64 <512000>; };
      opp576000 { opp-hz = /bits/ 64 <576000>; };
      opp640000 { opp-hz = /bits/ 64 <640000>; };
      opp704000 { opp-hz = /bits/ 64 <704000>; };
      opp768000 { opp-hz = /bits/ 64 <768000>; };
      opp832000 { opp-hz = /bits/ 64 <832000>; };
      opp896000 { opp-hz = /bits/ 64 <896000>; };
      opp960000 { opp-hz = /bits/ 64 <960000>; };
      opp1024000 { opp-hz = /bits/ 64 <1024000>; };

    };

    soc {
      #address-cells = <1>;
      #size-cells = <1>;

      cpufreq@1040000 {
        compatible = "virtual,android-v-only-cpufreq";
        reg = <0x1040000 0x10>;
      };
    };