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      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 
     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                     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      */
     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      */
     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