qcom android GPS 启动流程

1 LocationManagerService启动及初始化过程

(1) 在SystemServer.java的startOtherServices中添加LocationManagerService的代码如下：

try {    location = new LocationManagerService(context);    ServiceManager.addService(Context.LOCATION_SERVICE, location);} catch (Throwable e) {    reportWtf("starting Location Manager", e);}

(2) 在systemReady中调用systemRunning, 启动LocationManagerService的代码如下：

try {    if (locationF != null) locationF.systemRunning();} catch (Throwable e) {    reportWtf("Notifying Location Service running", e);}

(3) 准备GnssLocationProvider，LocationManagerService的systemRunning函数中会调用 loadProvidersLocked， 其代码如下：

private void loadProvidersLocked() {        // create a passive location provider, which is always enabled    PassiveProvider passiveProvider = new PassiveProvider(this);    addProviderLocked(passiveProvider);    mEnabledProviders.add(passiveProvider.getName());    mPassiveProvider = passiveProvider;    if (GnssLocationProvider.isSupported()) {        // Create a gps location provider        GnssLocationProvider gnssProvider = new GnssLocationProvider(mContext, this,                mLocationHandler.getLooper());        mGnssSystemInfoProvider = gnssProvider.getGnssSystemInfoProvider();        ......    }    ......}

(4) GnssLocationProvider的class_init_native方法。

该方法是一个静态方法，会在isSupported方法之前被调用。最终会调用到native函数中：android_location_GnssLocationProvider_class_init_native。
在这个函数中实现对gps.default.so的加载。

static void android_location_GnssLocationProvider_class_init_native(JNIEnv* env, jclass clazz) {    int err;    hw_module_t* module;    .......    err = hw_get_module(GPS_HARDWARE_MODULE_ID, (hw_module_t const**)&module);    if (err == 0) {        hw_device_t* device;        err = module->methods->open(module, GPS_HARDWARE_MODULE_ID, &device);        if (err == 0) {            gps_device_t* gps_device = (gps_device_t *)device;            sGpsInterface = gps_device->get_gps_interface(gps_device);        }    }    if (sGpsInterface) {        ......    }}

(5) sGpsInterface 接口：

static const GpsInterface sLocEngInterface ={   sizeof(GpsInterface),   loc_init,   loc_start,   loc_stop,   loc_cleanup,   loc_inject_time,   loc_inject_location,   loc_delete_aiding_data,   loc_set_position_mode,   loc_get_extension};

(6) Others interface:

具体实现请参考：/LINUX/android/hardware/qcom/gps/loc_api/libloc_api_50001/loc.cpp

if (sGpsInterface) {    sGpsXtraInterface =        (const GpsXtraInterface*)sGpsInterface->get_extension(GPS_XTRA_INTERFACE);    sAGpsInterface =        (const AGpsInterface*)sGpsInterface->get_extension(AGPS_INTERFACE);    sGpsNiInterface =        (const GpsNiInterface*)sGpsInterface->get_extension(GPS_NI_INTERFACE);    sGpsDebugInterface =        (const GpsDebugInterface*)sGpsInterface->get_extension(GPS_DEBUG_INTERFACE);    sAGpsRilInterface =        (const AGpsRilInterface*)sGpsInterface->get_extension(AGPS_RIL_INTERFACE);    sGpsGeofencingInterface =        (const GpsGeofencingInterface*)sGpsInterface->get_extension(GPS_GEOFENCING_INTERFACE);    sGpsMeasurementInterface =        (const GpsMeasurementInterface*)sGpsInterface->get_extension(GPS_MEASUREMENT_INTERFACE);    sGpsNavigationMessageInterface =        (const GpsNavigationMessageInterface*)sGpsInterface->get_extension(                GPS_NAVIGATION_MESSAGE_INTERFACE);    sGnssConfigurationInterface =        (const GnssConfigurationInterface*)sGpsInterface->get_extension(                GNSS_CONFIGURATION_INTERFACE);}

(7) GPS framework 回调函数库：

 GpsCallbacks sGpsCallbacks = {    sizeof(GpsCallbacks),    location_callback,    status_callback,    sv_status_callback,    nmea_callback,    set_capabilities_callback,    acquire_wakelock_callback,    release_wakelock_callback,    create_thread_callback,    request_utc_time_callback,    set_system_info_callback,    gnss_sv_status_callback,};GpsXtraCallbacks sGpsXtraCallbacks = {    xtra_download_request_callback,    create_thread_callback,};AGpsCallbacks sAGpsCallbacks = {    agps_status_callback,    create_thread_callback,};GpsNiCallbacks sGpsNiCallbacks = {    gps_ni_notify_callback,    create_thread_callback,};AGpsRilCallbacks sAGpsRilCallbacks = {    agps_request_set_id,    agps_request_ref_location,    create_thread_callback,};......

2 GPS启动流程

(1) GnssLocationProvider.java里处理GPS启动，关闭请求

@Override    public void handleMessage(Message msg) {    int message = msg.what;    switch (message) {        case ENABLE:            if (msg.arg1 == 1) {                handleEnable();            } else {                handleDisable();            }            break;    ......    }}

(2) handleEnable里启动native层初始化动作

private void handleEnable() {    if (DEBUG) Log.d(TAG, "handleEnable");    synchronized (mLock) {        if (mEnabled) return;        mEnabled = true;    }    boolean enabled = native_init();    if (enabled) {        mSupportsXtra = true;    } else {        synchronized (mLock) {            mEnabled = false;        }        Log.w(TAG, "Failed to enable location provider");    }}

(3) GPS native初始化，即GnssLocationProvider初始化过程：

static jboolean android_location_GnssLocationProvider_init(JNIEnv* env, jobject obj){    // this must be set before calling into the HAL library    if (!mCallbacksObj)        mCallbacksObj = env->NewGlobalRef(obj);    // fail if the main interface fails to initialize    if (!sGpsInterface || sGpsInterface->init(&sGpsCallbacks) != 0)        return JNI_FALSE;    // if XTRA initialization fails we will disable it by sGpsXtraInterface to NULL,    // but continue to allow the rest of the GPS interface to work.    if (sGpsXtraInterface && sGpsXtraInterface->init(&sGpsXtraCallbacks) != 0)        sGpsXtraInterface = NULL;    ......    return JNI_TRUE;}

(4) Loc_init, 设置framework层回调函数，初始化loc eng，并通过modem接口上电：

static int loc_init(GpsCallbacks* callbacks){    int retVal = -1;    ENTRY_LOG();    LOC_API_ADAPTER_EVENT_MASK_T event;    ......    LocCallbacks clientCallbacks = {local_loc_cb, /* location_cb */                                    callbacks->status_cb, /* status_cb */                                    local_sv_cb, /* sv_status_cb */                                    callbacks->nmea_cb, /* nmea_cb */                                    callbacks->set_capabilities_cb, /* set_capabilities_cb */                                    callbacks->acquire_wakelock_cb, /* acquire_wakelock_cb */                                    callbacks->release_wakelock_cb, /* release_wakelock_cb */                                    callbacks->create_thread_cb, /* create_thread_cb */                                    NULL, /* location_ext_parser */                                    NULL, /* sv_ext_parser */                                    callbacks->request_utc_time_cb, /* request_utc_time_cb */                                    callbacks->set_system_info_cb, /* set_system_info_cb */                                    callbacks->gnss_sv_status_cb, /* gnss_sv_status_cb */                                    };    gps_loc_cb = callbacks->location_cb;    gps_sv_cb = callbacks->sv_status_cb;    retVal = loc_eng_init(loc_afw_data, &clientCallbacks, event, NULL);    ......    if(retVal) {        LOC_LOGE("loc_eng_init() fail!");        goto err;    }    loc_afw_data.adapter->setPowerVoteRight(loc_get_target() == TARGET_QCA1530);    loc_afw_data.adapter->setPowerVote(true);    LOC_LOGD("loc_eng_init() success!");err:    EXIT_LOG(%d, retVal);    return retVal;}

(5) LocEngInit及msgTask初始化流程：