CpuFrequencies.java revision ce643a309e8d414395ec36188523d10eb64d6618 
1/*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16package com.android.server.power.batterysaver;
17
18import android.util.ArrayMap;
19import android.util.Slog;
20
21import com.android.internal.annotations.GuardedBy;
22
23import java.util.Map;
24
25
26/**
27 * Helper to parse a list of "core-number:frequency" pairs concatenated with / as a separator,
28 * and convert them into a map of "filename -> value" that should be written to
29 * /sys/.../scaling_max_freq.
30 *
31 * Example input: "0:1900800/4:2500000", which will be converted into:
32 *   "/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq" "1900800"
33 *   "/sys/devices/system/cpu/cpu4/cpufreq/scaling_max_freq" "2500000"
34 *
35 * Test:
36 atest $ANDROID_BUILD_TOP/frameworks/base/services/tests/servicestests/src/com/android/server/power/batterysaver/CpuFrequenciesTest.java
37 */
38public class CpuFrequencies {
39    private static final String TAG = "CpuFrequencies";
40
41    private final Object mLock = new Object();
42
43    @GuardedBy("mLock")
44    private final ArrayMap<Integer, Long> mCoreAndFrequencies = new ArrayMap<>();
45
46    public CpuFrequencies() {
47    }
48
49    /**
50     * Parse a string.
51     */
52    public CpuFrequencies parseString(String cpuNumberAndFrequencies) {
53        synchronized (mLock) {
54            mCoreAndFrequencies.clear();
55            try {
56                for (String pair : cpuNumberAndFrequencies.split("/")) {
57                    final String[] coreAndFreq = pair.split(":", 2);
58
59                    if (coreAndFreq.length != 2) {
60                        throw new IllegalArgumentException("Wrong format");
61                    }
62                    final int core = Integer.parseInt(coreAndFreq[0]);
63                    final long freq = Long.parseLong(coreAndFreq[1]);
64
65                    mCoreAndFrequencies.put(core, freq);
66                }
67            } catch (IllegalArgumentException e) {
68                Slog.wtf(TAG, "Invalid configuration: " + cpuNumberAndFrequencies, e);
69            }
70        }
71        return this;
72    }
73
74    /**
75     * Return a new map containing the filename-value pairs.
76     */
77    public ArrayMap<String, String> toSysFileMap() {
78        final ArrayMap<String, String> map = new ArrayMap<>();
79        addToSysFileMap(map);
80        return map;
81    }
82
83    /**
84     * Add the filename-value pairs to an existing map.
85     */
86    public void addToSysFileMap(Map<String, String> map) {
87        synchronized (mLock) {
88            final int size = mCoreAndFrequencies.size();
89
90            for (int i = 0; i < size; i++) {
91                final int core = mCoreAndFrequencies.keyAt(i);
92                final long freq = mCoreAndFrequencies.valueAt(i);
93
94                final String file = "/sys/devices/system/cpu/cpu" + Integer.toString(core) +
95                        "/cpufreq/scaling_max_freq";
96
97                map.put(file, Long.toString(freq));
98            }
99        }
100    }
101}
102