Merge "GPS Signal Quality added to BatteryStats"

8 files changed, 395 insertions, 4 deletions

diff --git a/core/java/android/os/BatteryStats.java b/core/java/android/os/BatteryStats.java
index 4c35a5c75c47..49879a8a84a7 100644
--- a/core/java/android/os/BatteryStats.java
+++ b/core/java/android/os/BatteryStats.java
@@ -35,6 +35,7 @@ import android.util.proto.ProtoOutputStream;
 import android.view.Display;
 
 import com.android.internal.annotations.VisibleForTesting;
+import com.android.internal.location.gnssmetrics.GnssMetrics;
 import com.android.internal.os.BatterySipper;
 import com.android.internal.os.BatteryStatsHelper;
 
@@ -1508,6 +1509,10 @@ public abstract class BatteryStats implements Parcelable {
         public static final int STATE2_WIFI_SIGNAL_STRENGTH_SHIFT = 4;
         public static final int STATE2_WIFI_SIGNAL_STRENGTH_MASK =
                 0x7 << STATE2_WIFI_SIGNAL_STRENGTH_SHIFT;
+        // Values for NUM_GPS_SIGNAL_QUALITY_LEVELS
+        public static final int STATE2_GPS_SIGNAL_QUALITY_SHIFT = 7;
+        public static final int STATE2_GPS_SIGNAL_QUALITY_MASK =
+            0x1 << STATE2_GPS_SIGNAL_QUALITY_SHIFT;
 
         public static final int STATE2_POWER_SAVE_FLAG = 1<<31;
         public static final int STATE2_VIDEO_ON_FLAG = 1<<30;
@@ -2096,6 +2101,23 @@ public abstract class BatteryStats implements Parcelable {
      */
     public abstract int getNumConnectivityChange(int which);
 
+
+    /**
+     * Returns the time in microseconds that the phone has been running with
+     * the given GPS signal quality level
+     *
+     * {@hide}
+     */
+    public abstract long getGpsSignalQualityTime(int strengthBin,
+        long elapsedRealtimeUs, int which);
+
+    /**
+     * Returns the GPS battery drain in mA-ms
+     *
+     * {@hide}
+     */
+    public abstract long getGpsBatteryDrainMaMs();
+
     /**
      * Returns the time in microseconds that the phone has been on while the device was
      * running on battery.
@@ -2320,6 +2342,9 @@ public abstract class BatteryStats implements Parcelable {
                 WIFI_SUPPL_STATE_NAMES, WIFI_SUPPL_STATE_SHORT_NAMES),
         new BitDescription(HistoryItem.STATE2_CAMERA_FLAG, "camera", "ca"),
         new BitDescription(HistoryItem.STATE2_BLUETOOTH_SCAN_FLAG, "ble_scan", "bles"),
+        new BitDescription(HistoryItem.STATE2_GPS_SIGNAL_QUALITY_MASK,
+            HistoryItem.STATE2_GPS_SIGNAL_QUALITY_SHIFT, "gps_signal_quality", "Gss",
+            new String[] { "poor", "good"}, new String[] { "poor", "good"}),
     };
 
     public static final String[] HISTORY_EVENT_NAMES = new String[] {
@@ -4740,6 +4765,43 @@ public abstract class BatteryStats implements Parcelable {
         pw.print(prefix);
         sb.setLength(0);
         sb.append(prefix);
+        sb.append("  GPS Statistics:");
+        pw.println(sb.toString());
+
+        sb.setLength(0);
+        sb.append(prefix);
+        sb.append("     GPS signal quality (Top 4 Average CN0):");
+        final String[] gpsSignalQualityDescription = new String[]{
+            "poor (less than 20 dBHz): ",
+            "good (greater than 20 dBHz): "};
+        final int numGpsSignalQualityBins = Math.min(GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS,
+            gpsSignalQualityDescription.length);
+        for (int i=0; i<numGpsSignalQualityBins; i++) {
+            final long time = getGpsSignalQualityTime(i, rawRealtime, which);
+            sb.append("\n    ");
+            sb.append(prefix);
+            sb.append("  ");
+            sb.append(gpsSignalQualityDescription[i]);
+            formatTimeMs(sb, time/1000);
+            sb.append("(");
+            sb.append(formatRatioLocked(time, whichBatteryRealtime));
+            sb.append(") ");
+        }
+        pw.println(sb.toString());
+
+        final long gpsBatteryDrainMaMs = getGpsBatteryDrainMaMs();
+        if (gpsBatteryDrainMaMs > 0) {
+            pw.print(prefix);
+            sb.setLength(0);
+            sb.append(prefix);
+            sb.append("     Battery Drain (mAh): ");
+            sb.append(Double.toString(((double) gpsBatteryDrainMaMs)/(3600 * 1000)));
+            pw.println(sb.toString());
+        }
+
+        pw.print(prefix);
+        sb.setLength(0);
+        sb.append(prefix);
         sb.append("  CONNECTIVITY POWER SUMMARY END");
         pw.println(sb.toString());
         pw.println("");
diff --git a/core/java/android/os/connectivity/GpsBatteryStats.aidl b/core/java/android/os/connectivity/GpsBatteryStats.aidl
new file mode 100644
index 000000000000..7b96d1a8e062
--- /dev/null
+++ b/core/java/android/os/connectivity/GpsBatteryStats.aidl
@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.os.connectivity;
+
+/** {@hide} */
+parcelable GpsBatteryStats;
\ No newline at end of file
diff --git a/core/java/android/os/connectivity/GpsBatteryStats.java b/core/java/android/os/connectivity/GpsBatteryStats.java
new file mode 100644
index 000000000000..f2ac5ef6d40b
--- /dev/null
+++ b/core/java/android/os/connectivity/GpsBatteryStats.java
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.os.connectivity;
+
+import android.os.Parcel;
+import android.os.Parcelable;
+
+import com.android.internal.location.gnssmetrics.GnssMetrics;
+
+import java.util.Arrays;
+
+/**
+ * API for GPS power stats
+ *
+ * @hide
+ */
+public final class GpsBatteryStats implements Parcelable {
+
+  private long mLoggingDurationMs;
+  private long mEnergyConsumedMaMs;
+  private long[] mTimeInGpsSignalQualityLevel;
+
+  public static final Parcelable.Creator<GpsBatteryStats> CREATOR = new
+      Parcelable.Creator<GpsBatteryStats>() {
+        public GpsBatteryStats createFromParcel(Parcel in) {
+          return new GpsBatteryStats(in);
+        }
+
+        public GpsBatteryStats[] newArray(int size) {
+          return new GpsBatteryStats[size];
+        }
+      };
+
+  public GpsBatteryStats() {
+    initialize();
+  }
+
+  @Override
+  public void writeToParcel(Parcel out, int flags) {
+    out.writeLong(mLoggingDurationMs);
+    out.writeLong(mEnergyConsumedMaMs);
+    out.writeLongArray(mTimeInGpsSignalQualityLevel);
+  }
+
+  public void readFromParcel(Parcel in) {
+    mLoggingDurationMs = in.readLong();
+    mEnergyConsumedMaMs = in.readLong();
+    in.readLongArray(mTimeInGpsSignalQualityLevel);
+  }
+
+  public long getLoggingDurationMs() {
+    return mLoggingDurationMs;
+  }
+
+  public long getEnergyConsumedMaMs() {
+    return mEnergyConsumedMaMs;
+  }
+
+  public long[] getTimeInGpsSignalQualityLevel() {
+    return mTimeInGpsSignalQualityLevel;
+  }
+
+  public void setLoggingDurationMs(long t) {
+    mLoggingDurationMs = t;
+    return;
+  }
+
+  public void setEnergyConsumedMaMs(long e) {
+    mEnergyConsumedMaMs = e;
+    return;
+  }
+
+  public void setTimeInGpsSignalQualityLevel(long[] t) {
+    mTimeInGpsSignalQualityLevel = Arrays.copyOfRange(t, 0,
+        Math.min(t.length, GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS));
+    return;
+  }
+
+  @Override
+  public int describeContents() {
+    return 0;
+  }
+
+  private GpsBatteryStats(Parcel in) {
+    initialize();
+    readFromParcel(in);
+  }
+
+  private void initialize() {
+    mLoggingDurationMs = 0;
+    mEnergyConsumedMaMs = 0;
+    mTimeInGpsSignalQualityLevel = new long[GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS];
+    return;
+  }
+}
\ No newline at end of file
diff --git a/core/java/com/android/internal/app/IBatteryStats.aidl b/core/java/com/android/internal/app/IBatteryStats.aidl
index 388180dc61e0..e2d1ad59043e 100644
--- a/core/java/com/android/internal/app/IBatteryStats.aidl
+++ b/core/java/com/android/internal/app/IBatteryStats.aidl
@@ -23,6 +23,7 @@ import android.net.wifi.WifiActivityEnergyInfo;
 import android.os.ParcelFileDescriptor;
 import android.os.WorkSource;
 import android.os.connectivity.CellularBatteryStats;
+import android.os.connectivity.GpsBatteryStats;
 import android.os.health.HealthStatsParceler;
 import android.telephony.DataConnectionRealTimeInfo;
 import android.telephony.ModemActivityInfo;
@@ -91,6 +92,7 @@ interface IBatteryStats {
     void noteVibratorOff(int uid);
     void noteStartGps(int uid);
     void noteStopGps(int uid);
+    void noteGpsSignalQuality(int signalLevel);
     void noteScreenState(int state);
     void noteScreenBrightness(int brightness);
     void noteUserActivity(int uid, int event);
@@ -140,6 +142,9 @@ interface IBatteryStats {
     /** {@hide} */
     CellularBatteryStats getCellularBatteryStats();
 
+    /** {@hide} */
+    GpsBatteryStats getGpsBatteryStats();
+
     HealthStatsParceler takeUidSnapshot(int uid);
     HealthStatsParceler[] takeUidSnapshots(in int[] uid);
 
diff --git a/core/java/com/android/internal/os/BatteryStatsImpl.java b/core/java/com/android/internal/os/BatteryStatsImpl.java
index b4bfee5802ff..bd22b33f9507 100644
--- a/core/java/com/android/internal/os/BatteryStatsImpl.java
+++ b/core/java/com/android/internal/os/BatteryStatsImpl.java
@@ -34,6 +34,7 @@ import android.os.BatteryManager;
 import android.os.BatteryStats;
 import android.os.Build;
 import android.os.connectivity.CellularBatteryStats;
+import android.os.connectivity.GpsBatteryStats;
 import android.os.FileUtils;
 import android.os.Handler;
 import android.os.IBatteryPropertiesRegistrar;
@@ -78,6 +79,7 @@ import android.view.Display;
 
 import com.android.internal.annotations.GuardedBy;
 import com.android.internal.annotations.VisibleForTesting;
+import com.android.internal.location.gnssmetrics.GnssMetrics;
 import com.android.internal.net.NetworkStatsFactory;
 import com.android.internal.util.ArrayUtils;
 import com.android.internal.util.FastPrintWriter;
@@ -672,6 +674,10 @@ public class BatteryStatsImpl extends BatteryStats {
     int mCameraOnNesting;
     StopwatchTimer mCameraOnTimer;
 
+    int mGpsSignalQualityBin = -1;
+    final StopwatchTimer[] mGpsSignalQualityTimer =
+        new StopwatchTimer[GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS];
+
     int mPhoneSignalStrengthBin = -1;
     int mPhoneSignalStrengthBinRaw = -1;
     final StopwatchTimer[] mPhoneSignalStrengthsTimer =
@@ -4583,10 +4589,37 @@ public class BatteryStatsImpl extends BatteryStats {
             if (DEBUG_HISTORY) Slog.v(TAG, "Stop GPS to: "
                     + Integer.toHexString(mHistoryCur.states));
             addHistoryRecordLocked(elapsedRealtime, uptime);
+            stopAllGpsSignalQualityTimersLocked(-1);
+            mGpsSignalQualityBin = -1;
         }
         getUidStatsLocked(uid).noteStopGps(elapsedRealtime);
     }
 
+    public void noteGpsSignalQualityLocked(int signalLevel) {
+        if (mGpsNesting == 0) {
+            return;
+        }
+        if (signalLevel < 0 || signalLevel >= GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS) {
+            stopAllGpsSignalQualityTimersLocked(-1);
+            return;
+        }
+        final long elapsedRealtime = mClocks.elapsedRealtime();
+        final long uptime = mClocks.uptimeMillis();
+        if (mGpsSignalQualityBin != signalLevel) {
+            if (mGpsSignalQualityBin >= 0) {
+                mGpsSignalQualityTimer[mGpsSignalQualityBin].stopRunningLocked(elapsedRealtime);
+            }
+            if(!mGpsSignalQualityTimer[signalLevel].isRunningLocked()) {
+                mGpsSignalQualityTimer[signalLevel].startRunningLocked(elapsedRealtime);
+            }
+            mHistoryCur.states2 = (mHistoryCur.states2&~HistoryItem.STATE2_GPS_SIGNAL_QUALITY_MASK)
+                    | (signalLevel << HistoryItem.STATE2_GPS_SIGNAL_QUALITY_SHIFT);
+            addHistoryRecordLocked(elapsedRealtime, uptime);
+            mGpsSignalQualityBin = signalLevel;
+        }
+        return;
+    }
+
     public void noteScreenStateLocked(int state) {
         state = mPretendScreenOff ? Display.STATE_OFF : state;
 
@@ -4920,6 +4953,18 @@ public class BatteryStatsImpl extends BatteryStats {
         mDailyPackageChanges.add(pc);
     }
 
+    void stopAllGpsSignalQualityTimersLocked(int except) {
+        final long elapsedRealtime = mClocks.elapsedRealtime();
+        for (int i = 0; i < GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS; i++) {
+            if (i == except) {
+                continue;
+            }
+            while (mGpsSignalQualityTimer[i].isRunningLocked()) {
+                mGpsSignalQualityTimer[i].stopRunningLocked(elapsedRealtime);
+            }
+        }
+    }
+
     public void notePhoneOnLocked() {
         if (!mPhoneOn) {
             final long elapsedRealtime = mClocks.elapsedRealtime();
@@ -6131,6 +6176,20 @@ public class BatteryStatsImpl extends BatteryStats {
         return val;
     }
 
+    @Override public long getGpsSignalQualityTime(int strengthBin,
+        long elapsedRealtimeUs, int which) {
+        if (strengthBin < 0 || strengthBin >= GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS) {
+            return 0;
+        }
+        return mGpsSignalQualityTimer[strengthBin].getTotalTimeLocked(
+            elapsedRealtimeUs, which);
+    }
+
+    @Override public long getGpsBatteryDrainMaMs() {
+        //TODO: Add GPS power computation (b/67213967)
+        return 0;
+    }
+
     @Override public long getPhoneOnTime(long elapsedRealtimeUs, int which) {
         return mPhoneOnTimer.getTotalTimeLocked(elapsedRealtimeUs, which);
     }
@@ -9857,6 +9916,10 @@ public class BatteryStatsImpl extends BatteryStats {
             mWifiSignalStrengthsTimer[i] = new StopwatchTimer(mClocks, null, -800-i, null,
                     mOnBatteryTimeBase);
         }
+        for (int i=0; i< GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS; i++) {
+            mGpsSignalQualityTimer[i] = new StopwatchTimer(mClocks, null, -1000-i, null,
+                mOnBatteryTimeBase);
+        }
         mAudioOnTimer = new StopwatchTimer(mClocks, null, -7, null, mOnBatteryTimeBase);
         mVideoOnTimer = new StopwatchTimer(mClocks, null, -8, null, mOnBatteryTimeBase);
         mFlashlightOnTimer = new StopwatchTimer(mClocks, null, -9, null, mOnBatteryTimeBase);
@@ -10546,6 +10609,9 @@ public class BatteryStatsImpl extends BatteryStats {
             mWifiSignalStrengthsTimer[i].reset(false);
         }
         mWifiMulticastWakelockTimer.reset(false);
+        for (int i=0; i< GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS; i++) {
+            mGpsSignalQualityTimer[i].reset(false);
+        }
         mWifiActivity.reset(false);
         mBluetoothActivity.reset(false);
         mModemActivity.reset(false);
@@ -12464,6 +12530,21 @@ public class BatteryStatsImpl extends BatteryStats {
         return s;
     }
 
+    /*@hide */
+    public GpsBatteryStats getGpsBatteryStats() {
+        GpsBatteryStats s = new GpsBatteryStats();
+        final int which = STATS_SINCE_CHARGED;
+        final long rawRealTime = SystemClock.elapsedRealtime() * 1000;
+        s.setLoggingDurationMs(computeBatteryRealtime(rawRealTime, which) / 1000);
+        s.setEnergyConsumedMaMs(getGpsBatteryDrainMaMs());
+        long[] time = new long[GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS];
+        for (int i=0; i<time.length; i++) {
+            time[i] = getGpsSignalQualityTime(i, rawRealTime, which) / 1000;
+        }
+        s.setTimeInGpsSignalQualityLevel(time);
+        return s;
+    }
+
     @Override
     public LevelStepTracker getChargeLevelStepTracker() {
         return mChargeStepTracker;
@@ -13141,6 +13222,9 @@ public class BatteryStatsImpl extends BatteryStats {
         for (int i=0; i<NUM_WIFI_SIGNAL_STRENGTH_BINS; i++) {
             mWifiSignalStrengthsTimer[i].readSummaryFromParcelLocked(in);
         }
+        for (int i=0; i<GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS; i++) {
+            mGpsSignalQualityTimer[i].readSummaryFromParcelLocked(in);
+        }
         mWifiActivity.readSummaryFromParcel(in);
         mBluetoothActivity.readSummaryFromParcel(in);
         mModemActivity.readSummaryFromParcel(in);
@@ -13583,6 +13667,9 @@ public class BatteryStatsImpl extends BatteryStats {
         for (int i=0; i<NUM_WIFI_SIGNAL_STRENGTH_BINS; i++) {
             mWifiSignalStrengthsTimer[i].writeSummaryFromParcelLocked(out, NOWREAL_SYS);
         }
+        for (int i=0; i< GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS; i++) {
+            mGpsSignalQualityTimer[i].writeSummaryFromParcelLocked(out, NOWREAL_SYS);
+        }
         mWifiActivity.writeSummaryToParcel(out);
         mBluetoothActivity.writeSummaryToParcel(out);
         mModemActivity.writeSummaryToParcel(out);
@@ -14058,7 +14145,10 @@ public class BatteryStatsImpl extends BatteryStats {
             mWifiSignalStrengthsTimer[i] = new StopwatchTimer(mClocks, null, -800-i,
                     null, mOnBatteryTimeBase, in);
         }
-
+        for (int i=0; i<GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS; i++) {
+            mGpsSignalQualityTimer[i] = new StopwatchTimer(mClocks, null, -1000-i,
+                null, mOnBatteryTimeBase, in);
+        }
         mWifiActivity = new ControllerActivityCounterImpl(mOnBatteryTimeBase,
                 NUM_WIFI_TX_LEVELS, in);
         mBluetoothActivity = new ControllerActivityCounterImpl(mOnBatteryTimeBase,
@@ -14258,6 +14348,9 @@ public class BatteryStatsImpl extends BatteryStats {
         for (int i=0; i<NUM_WIFI_SIGNAL_STRENGTH_BINS; i++) {
             mWifiSignalStrengthsTimer[i].writeToParcel(out, uSecRealtime);
         }
+        for (int i=0; i< GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS; i++) {
+            mGpsSignalQualityTimer[i].writeToParcel(out, uSecRealtime);
+        }
         mWifiActivity.writeToParcel(out, 0);
         mBluetoothActivity.writeToParcel(out, 0);
         mModemActivity.writeToParcel(out, 0);
@@ -14452,6 +14545,10 @@ public class BatteryStatsImpl extends BatteryStats {
                 pr.println("*** Wifi signal strength #" + i + ":");
                 mWifiSignalStrengthsTimer[i].logState(pr, "  ");
             }
+            for (int i=0; i<GnssMetrics.NUM_GPS_SIGNAL_QUALITY_LEVELS; i++) {
+                pr.println("*** GPS signal quality #" + i + ":");
+                mGpsSignalQualityTimer[i].logState(pr, "  ");
+            }
             pr.println("*** Flashlight timer:");
             mFlashlightOnTimer.logState(pr, "  ");
             pr.println("*** Camera timer:");
diff --git a/location/java/com/android/internal/location/gnssmetrics/GnssMetrics.java b/location/java/com/android/internal/location/gnssmetrics/GnssMetrics.java
index 833376cfa057..603926f4fe4d 100644
--- a/location/java/com/android/internal/location/gnssmetrics/GnssMetrics.java
+++ b/location/java/com/android/internal/location/gnssmetrics/GnssMetrics.java
@@ -19,10 +19,12 @@ package com.android.internal.location.gnssmetrics;
 import android.os.SystemClock;
 
 import android.util.Base64;
+import android.util.Log;
 import android.util.TimeUtils;
 
 import java.util.Arrays;
 
+import com.android.internal.app.IBatteryStats;
 import com.android.internal.location.nano.GnssLogsProto.GnssLog;
 
 /**
@@ -31,14 +33,29 @@ import com.android.internal.location.nano.GnssLogsProto.GnssLog;
  */
 public class GnssMetrics {
 
+  private static final String TAG = GnssMetrics.class.getSimpleName();
+
+  /* Constant which indicates GPS signal quality is poor */
+  public static final int GPS_SIGNAL_QUALITY_POOR = 0;
+
+  /* Constant which indicates GPS signal quality is good */
+  public static final int GPS_SIGNAL_QUALITY_GOOD = 1;
+
+  /* Number of GPS signal quality levels */
+  public static final int NUM_GPS_SIGNAL_QUALITY_LEVELS = GPS_SIGNAL_QUALITY_GOOD + 1;
+
   /** Default time between location fixes (in millisecs) */
   private static final int DEFAULT_TIME_BETWEEN_FIXES_MILLISECS = 1000;
 
   /* The time since boot when logging started */
   private String logStartInElapsedRealTime;
 
+  /* GNSS power metrics */
+  private GnssPowerMetrics mGnssPowerMetrics;
+
   /** Constructor */
-  public GnssMetrics() {
+  public GnssMetrics(IBatteryStats stats) {
+    mGnssPowerMetrics = new GnssPowerMetrics(stats);
     locationFailureStatistics = new Statistics();
     timeToFirstFixSecStatistics = new Statistics();
     positionAccuracyMeterStatistics = new Statistics();
@@ -103,11 +120,18 @@ public class GnssMetrics {
   *
   */
   public void logCn0(float[] cn0s, int numSv) {
-    if (numSv < 4) {
+    if (numSv == 0 || cn0s == null || cn0s.length == 0 || cn0s.length < numSv) {
+      if (numSv == 0) {
+         mGnssPowerMetrics.reportSignalQuality(null, 0);
+      }
       return;
     }
     float[] cn0Array = Arrays.copyOf(cn0s, numSv);
     Arrays.sort(cn0Array);
+    mGnssPowerMetrics.reportSignalQuality(cn0Array, numSv);
+    if (numSv < 4) {
+      return;
+    }
     if (cn0Array[numSv - 4] > 0.0) {
       double top4AvgCn0 = 0.0;
       for (int i = numSv - 4; i < numSv; i++) {
@@ -265,4 +289,62 @@ public class GnssMetrics {
     topFourAverageCn0Statistics.reset();
     return;
   }
+
+  /* Class for handling GNSS power related metrics */
+  private class GnssPowerMetrics {
+
+    /* Threshold for Top Four Average CN0 below which GNSS signal quality is declared poor */
+    private static final double POOR_TOP_FOUR_AVG_CN0_THRESHOLD_DB_HZ = 20.0;
+
+    /* Minimum change in Top Four Average CN0 needed to trigger a report */
+    private static final double REPORTING_THRESHOLD_DB_HZ = 1.0;
+
+    /* BatteryStats API */
+    private final IBatteryStats mBatteryStats;
+
+    /* Last reported Top Four Average CN0 */
+    private double mLastAverageCn0;
+
+    public GnssPowerMetrics(IBatteryStats stats) {
+      mBatteryStats = stats;
+      // Used to initialize the variable to a very small value (unachievable in practice) so that
+      // the first CNO report will trigger an update to BatteryStats
+      mLastAverageCn0 = -100.0;
+    }
+
+    /**
+     * Reports signal quality to BatteryStats. Signal quality is based on Top four average CN0. If
+     * the number of SVs seen is less than 4, then signal quality is the average CN0.
+     * Changes are reported only if the average CN0 changes by more than REPORTING_THRESHOLD_DB_HZ.
+     */
+    public void reportSignalQuality(float[] ascendingCN0Array, int numSv) {
+      double avgCn0 = 0.0;
+      if (numSv > 0) {
+        for (int i = Math.max(0, numSv - 4); i < numSv; i++) {
+          avgCn0 += (double) ascendingCN0Array[i];
+        }
+        avgCn0 /= Math.min(numSv, 4);
+      }
+      if (Math.abs(avgCn0 - mLastAverageCn0) < REPORTING_THRESHOLD_DB_HZ) {
+        return;
+      }
+      try {
+        mBatteryStats.noteGpsSignalQuality(getSignalLevel(avgCn0));
+        mLastAverageCn0 = avgCn0;
+      } catch (Exception e) {
+        Log.w(TAG, "Exception", e);
+      }
+      return;
+    }
+
+    /**
+     * Obtains signal level based on CN0
+     */
+    private int getSignalLevel(double cn0) {
+      if (cn0 > POOR_TOP_FOUR_AVG_CN0_THRESHOLD_DB_HZ) {
+        return GnssMetrics.GPS_SIGNAL_QUALITY_GOOD;
+      }
+      return GnssMetrics.GPS_SIGNAL_QUALITY_POOR;
+    }
+  }
 }
\ No newline at end of file
diff --git a/services/core/java/com/android/server/am/BatteryStatsService.java b/services/core/java/com/android/server/am/BatteryStatsService.java
index 81e8eb0d4136..207aaa76e5b8 100644
--- a/services/core/java/com/android/server/am/BatteryStatsService.java
+++ b/services/core/java/com/android/server/am/BatteryStatsService.java
@@ -40,6 +40,7 @@ import android.os.UserManagerInternal;
 import android.os.WorkSource;
 import android.os.WorkSource.WorkChain;
 import android.os.connectivity.CellularBatteryStats;
+import android.os.connectivity.GpsBatteryStats;
 import android.os.health.HealthStatsParceler;
 import android.os.health.HealthStatsWriter;
 import android.os.health.UidHealthStats;
@@ -594,6 +595,12 @@ public final class BatteryStatsService extends IBatteryStats.Stub
         }
     }
 
+    public void noteGpsSignalQuality(int signalLevel) {
+        synchronized (mStats) {
+            mStats.noteGpsSignalQualityLocked(signalLevel);
+        }
+    }
+
     public void noteScreenState(int state) {
         enforceCallingPermission();
         if (DBG) Slog.d(TAG, "begin noteScreenState");
@@ -1448,6 +1455,16 @@ public final class BatteryStatsService extends IBatteryStats.Stub
     }
 
     /**
+     * Gets a snapshot of Gps stats
+     * @hide
+     */
+    public GpsBatteryStats getGpsBatteryStats() {
+        synchronized (mStats) {
+            return mStats.getGpsBatteryStats();
+        }
+    }
+
+    /**
      * Gets a snapshot of the system health for a particular uid.
      */
     @Override
diff --git a/services/core/java/com/android/server/location/GnssLocationProvider.java b/services/core/java/com/android/server/location/GnssLocationProvider.java
index 6dc5403acc99..48d275cc483f 100644
--- a/services/core/java/com/android/server/location/GnssLocationProvider.java
+++ b/services/core/java/com/android/server/location/GnssLocationProvider.java
@@ -827,7 +827,7 @@ public class GnssLocationProvider implements LocationProviderInterface {
                 return isEnabled();
             }
         };
-        mGnssMetrics = new GnssMetrics();
+        mGnssMetrics = new GnssMetrics(mBatteryStats);
     }
 
     /**