WiFi: SAR Support: Add SarInfo

Current implementation has limited support for SAR in Wifi.
It just includes the support of power backoff when an ongoing
voice call is happening while Wifi is transmitting.

This commit is the first stage to provide more support for SAR
for WiFi TX power backoff when the device is in close proximity
to head or body of user with or without the presence of a voice call.

This stage adds the SarInfo which is a data structure that is used
by SarManager to communicate SAR triggers towards the WifiVendorHal

Bug: 65174506
Test: Run Wifi unit test suite
Test: ./frameworks/opt/net/wifi/tests/wifitests/runtests.sh
Change-Id: Ic5f002430db1e92f656ae861e65934241a8590ef
Signed-off-by: Ahmed ElArabawy <arabawy@google.com>

1 files changed, 194 insertions, 0 deletions

diff --git a/service/java/com/android/server/wifi/SarInfo.java b/service/java/com/android/server/wifi/SarInfo.java
new file mode 100644
index 000000000..6eb777c65
--- /dev/null
+++ b/service/java/com/android/server/wifi/SarInfo.java
@@ -0,0 +1,194 @@
+/*
+ * Copyright (C) 2018 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 com.android.server.wifi;
+
+import java.io.FileDescriptor;
+import java.io.PrintWriter;
+
+/**
+ * This class represents the list of SAR inputs that will be used to select the proper
+ * power profile.
+ * This includes:
+ *  - SAR body sensor status
+ *  - Is there an ongoing voice call
+ *  - Is SoftAP active
+ * It also contains info about state of the other Wifi modes
+ *  - Client mode (Sta)
+ *  - ScanOnly mode
+ * It also keeps history for the reporting of SAR states/scenario to avoid unnecessary reporting
+ *  - keeps track of the last reported states
+ *  - keeps track of the last reported SAR scenario
+ *  - keeps track of if all wifi modes were disabled (no reporting should happen then)
+ */
+public class SarInfo {
+    /**
+     * This value is used as an initial value for the last reported scenario
+     * It is intended to be different than all valid SAR scenario values (including the
+     * reset value).
+     * Using this to initialize the lastReportedScenario results in that the first scenario
+     * (including reset) would be reported.
+     */
+    public static final int INITIAL_SAR_SCENARIO = -2;
+
+    /**
+     * This value is used for the reset scenario (no TX Power backoff)
+     * Valid scenario values only include scenarios with Tx Power backoff,
+     * so we need this one to represent the "No backoff" case.
+     */
+    public static final int RESET_SAR_SCENARIO = -1;
+
+    private static final String SAR_SENSOR_FREE_SPACE_STR = "SAR_SENSOR_FREE_SPACE";
+    private static final String SAR_SENSOR_NEAR_BODY_STR  = "SAR_SENSOR_NEAR_BODY";
+    private static final String SAR_SENSOR_NEAR_HAND_STR  = "SAR_SENSOR_NEAR_HAND";
+    private static final String SAR_SENSOR_NEAR_HEAD_STR  = "SAR_SENSOR_NEAR_HEAD";
+
+    public static final int SAR_SENSOR_FREE_SPACE = 1;
+    public static final int SAR_SENSOR_NEAR_HAND  = 2;
+    public static final int SAR_SENSOR_NEAR_HEAD  = 3;
+    public static final int SAR_SENSOR_NEAR_BODY  = 4;
+
+    /* For Logging */
+    private static final String TAG = "WifiSarInfo";
+
+    public boolean mSarSensorEnabled;
+
+    public int mSensorState = SAR_SENSOR_FREE_SPACE;
+    public boolean mIsWifiClientEnabled = false;
+    public boolean mIsWifiSapEnabled = false;
+    public boolean mIsWifiScanOnlyEnabled = false;
+    public boolean mIsVoiceCall = false;
+    public int mAttemptedSarScenario = RESET_SAR_SCENARIO;
+
+    private boolean mAllWifiDisabled = true;
+
+    /* Variables representing the last successfully reported values to hal */
+    private int mLastReportedSensorState = SAR_SENSOR_FREE_SPACE;
+    private boolean mLastReportedIsWifiSapEnabled = false;
+    private boolean mLastReportedIsVoiceCall = false;
+    private int mLastReportedScenario = INITIAL_SAR_SCENARIO;
+
+    SarInfo(boolean sarSensorEnabled) {
+        mSarSensorEnabled = sarSensorEnabled;
+    }
+
+    /**
+     * shouldReport()
+     * This method returns false in the following cases:
+     * 1. If all Wifi modes are disabled.
+     * 2. Values contributing to the SAR scenario selection have not changed
+     *    since last successful reporting.
+     *
+     * Special cases to allow for devices that require setting the SAR scenario value
+     * when the chip comes up (initial startup, or during operation)
+     * 1. This method would report true even with unchanged values from last reporting,
+     *    if any wifi mode is just enabled after all wifi modes were disabled.
+     * 2. This method would report true the first time it is called with any wifi mode enabled.
+     */
+    public boolean shouldReport() {
+        /* Check if all Wifi modes are disabled */
+        if (!mIsWifiClientEnabled && !mIsWifiSapEnabled && !mIsWifiScanOnlyEnabled) {
+            mAllWifiDisabled = true;
+            return false;
+        }
+
+        /* Check if Wifi was all disabled before this call */
+        if (mAllWifiDisabled) {
+            return true;
+        }
+
+        /* Check if some change happened since last successful reporting */
+        if ((mSensorState != mLastReportedSensorState)
+                || (mIsWifiSapEnabled != mLastReportedIsWifiSapEnabled)
+                || (mIsVoiceCall != mLastReportedIsVoiceCall)) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    /**
+     * reportingSuccessful()
+     * This method is called when reporting SAR scenario is fully successful
+     * This results in caching the last reported inputs for future comparison.
+     */
+    public void reportingSuccessful() {
+        mLastReportedSensorState = mSensorState;
+        mLastReportedIsWifiSapEnabled = mIsWifiSapEnabled;
+        mLastReportedIsVoiceCall = mIsVoiceCall;
+        mLastReportedScenario = mAttemptedSarScenario;
+
+        mAllWifiDisabled = false;
+    }
+
+    /**
+     *  resetSarScenarioNeeded()
+     *  Returns true if a call towards HAL to reset SAR scenario would be necessary.
+     *  Returns false if the last call to HAL was already a reset, and hence
+     *  another call to reset the SAR scenario would be redundant.
+     */
+    public boolean resetSarScenarioNeeded() {
+        return setSarScenarioNeeded(RESET_SAR_SCENARIO);
+    }
+
+    /**
+     * setSarScenarioNeeded()
+     * Returns true if a call towards HAL to set SAR scenario to that value would be
+     * necessary.
+     * Returns false if the last call to HAL was to set the scenario to that value, hence,
+     * another call to set the SAR scenario to the same value would be redundant.
+     */
+    public boolean setSarScenarioNeeded(int scenario) {
+        mAttemptedSarScenario = scenario;
+        return (mLastReportedScenario != scenario);
+    }
+
+    /**
+     * dump()
+     * Dumps the state of SarInfo
+     */
+    public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
+        pw.println("*** WiFi SAR Info Dump  ***");
+        pw.println("Current values:");
+        pw.println("    Sensor state is: " + sensorStateToString(mSensorState));
+        pw.println("    Voice Call state is: " + mIsVoiceCall);
+        pw.println("    Wifi Client state is: " + mIsWifiClientEnabled);
+        pw.println("    Wifi Soft AP state is: " + mIsWifiSapEnabled);
+        pw.println("    Wifi ScanOnly state is: " + mIsWifiScanOnlyEnabled);
+        pw.println("Last reported values:");
+        pw.println("    Sensor state is: " + sensorStateToString(mLastReportedSensorState));
+        pw.println("    Soft AP state is: " + mLastReportedIsWifiSapEnabled);
+        pw.println("    Voice Call state is: " + mLastReportedIsVoiceCall);
+    }
+
+    /**
+     * Convert SAR sensor state to string
+     */
+    public static String sensorStateToString(int sensorState) {
+        switch(sensorState) {
+            case SAR_SENSOR_FREE_SPACE:
+                return SAR_SENSOR_FREE_SPACE_STR;
+            case SAR_SENSOR_NEAR_BODY:
+                return SAR_SENSOR_NEAR_BODY_STR;
+            case SAR_SENSOR_NEAR_HAND:
+                return SAR_SENSOR_NEAR_HAND_STR;
+            case SAR_SENSOR_NEAR_HEAD:
+                return SAR_SENSOR_NEAR_HEAD_STR;
+            default:
+                return "Invalid SAR sensor state";
+        }
+    }
+}