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  */
16 package com.android.server.power.batterysaver;
17 
18 import android.util.ArrayMap;
19 import android.util.Slog;
20 
21 import com.android.internal.annotations.GuardedBy;
22 
23 import 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  */
38 public 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 
CpuFrequencies()46     public CpuFrequencies() {
47     }
48 
49     /**
50      * Parse a string.
51      */
parseString(String cpuNumberAndFrequencies)52     public CpuFrequencies parseString(String cpuNumberAndFrequencies) {
53         synchronized (mLock) {
54             mCoreAndFrequencies.clear();
55             try {
56                 for (String pair : cpuNumberAndFrequencies.split("/")) {
57                     pair = pair.trim();
58                     if (pair.length() == 0) {
59                         continue;
60                     }
61                     final String[] coreAndFreq = pair.split(":", 2);
62 
63                     if (coreAndFreq.length != 2) {
64                         throw new IllegalArgumentException("Wrong format");
65                     }
66                     final int core = Integer.parseInt(coreAndFreq[0]);
67                     final long freq = Long.parseLong(coreAndFreq[1]);
68 
69                     mCoreAndFrequencies.put(core, freq);
70                 }
71             } catch (IllegalArgumentException e) {
72                 Slog.wtf(TAG, "Invalid configuration: '" + cpuNumberAndFrequencies + "'");
73             }
74         }
75         return this;
76     }
77 
78     /**
79      * Return a new map containing the filename-value pairs.
80      */
toSysFileMap()81     public ArrayMap<String, String> toSysFileMap() {
82         final ArrayMap<String, String> map = new ArrayMap<>();
83         addToSysFileMap(map);
84         return map;
85     }
86 
87     /**
88      * Add the filename-value pairs to an existing map.
89      */
addToSysFileMap(Map<String, String> map)90     public void addToSysFileMap(Map<String, String> map) {
91         synchronized (mLock) {
92             final int size = mCoreAndFrequencies.size();
93 
94             for (int i = 0; i < size; i++) {
95                 final int core = mCoreAndFrequencies.keyAt(i);
96                 final long freq = mCoreAndFrequencies.valueAt(i);
97 
98                 final String file = "/sys/devices/system/cpu/cpu" + Integer.toString(core) +
99                         "/cpufreq/scaling_max_freq";
100 
101                 map.put(file, Long.toString(freq));
102             }
103         }
104     }
105 }
106