sdk/fidl/fuchsia.hardware.cpu.ctrl/ctrl.fidl

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
library fuchsia.hardware.cpu.ctrl;

using zx;

/// CpuPerformanceStateInfo::frequency_hz and CpuPerformanceStateInfo::voltage_uv
/// are set to this if the frequency and voltage for the given performance state
/// are unknown respectively.
const FREQUENCY_UNKNOWN int64 = -1;
const VOLTAGE_UNKNOWN int64 = -1;

const DEVICE_PERFORMANCE_STATE_P0 uint32 = 0;
const MAX_DEVICE_PERFORMANCE_STATES uint32 = 20;

/// A collection of some basic information for a given performance state.
type CpuPerformanceStateInfo = struct {
    /// Frequency the core is operating at in hertz.
    frequency_hz int64;

    // Voltage the core is operating at in microvolts.
    voltage_uv int64;
};

closed protocol Device {
    /// Returns information about a given performance state for this performance
    /// domain.
    strict GetPerformanceStateInfo(struct {
        state uint32;
    }) -> (struct {
        info CpuPerformanceStateInfo;
    }) error zx.Status;

    /// Gets the current performance state of the device.
    strict GetCurrentPerformanceState() -> (struct {
        out_state uint32;
    });

    /// Set the performance state of this device to the requested performance state.
    /// Returns ZX_OK, if the device is in a working state and the performance state is changed to
    /// requested_state successfully. out_state will be same as requested_state.
    /// Returns error status, if switching to the requested_state was unsuccessful. out_state
    /// is the state that the device is currently in.
    strict SetPerformanceState(struct {
        requested_state uint32;
    }) -> (struct {
        out_state uint32;
    }) error zx.Status;

    /// Returns the number of logical cores contained within this performance
    /// domain.
    strict GetNumLogicalCores() -> (struct {
        count uint64;
    });

    /// Returns a global system-wide core ID for the nth core in this
    /// performance domain. `index` must be a value in the range [0, n) where
    /// n is the value returned by GetNumLogicalCores().
    strict GetLogicalCoreId(struct {
        index uint64;
    }) -> (struct {
        id uint64;
    });
};