Android wifi打开流程(Android O)

根据自己的理解整理了Android O的wifi启动流程，为便于理解，绘制了Android O wifi架构图。有理解不到之处和错误之处，请各位指出，一起学习。

一. Android O wifi 架构：

由于Android O的Treble化，Android O上Wifi架构变动也比较大，尤其是JNI层、Hal层、HIDL层。

下图是Android O Treble HIDL大致结构：

下图是Android O wifi架构：

二. 函数调用流程：

1. 在wifisettings activity的onStart函数中，创建一个WifiEnabler对象，用于实现wifi开关功能。

packages/apps/Settings/src/com/android/settings/wifi/WifiSettings.java

onStart()

mWifiEnabler = createWifiEnabler();

2. WifiEnabler开关SwitchToggled中会调用WifiManager.setWifiEnabled方法。

packages/apps/Settings/src/com/android/settings/wifi/WifiEnabler.java

onSwithToggled(boolean isCkecked)

mWifiManager.setWifiEnabled(isChecked)

3. WifiManager调用WifiService的方法。

frameworks/base/wifi/java/android/net/wifi/WifiManager.java

setWifiEnabled(boolean enabled)

mService.setWifiEnabled(mContext.getOpPackageName(), enabled)

4. WiFiManager使用aidl方式和WifiService进行通信。

frameworks/base/wifi/java/android/net/wifi/IWifiManager.aidl

boolean setWifiEnabled(String packageName, boolean enable);

5. WifiServiceImpl中实现WifiService的方法，像WifiController发消息：CMD_WIFI_TOGGLED.

frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiServiceImpl.java

public synchronized boolean setWifiEnabled(String packageName, boolean enable)

mWifiController.sendMessage(CMD_WIFI_TOGGLED);

6. WifiController状态机处理消息：CMD_WIFI_TOGGLED

frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiController.java

WifiController状态机的状态变化，这里我们只说softap关闭状态下打开sta的情况；有时间的话，可以跟一下softap打开状态下打开sta的流程。这里只需关注“Turn ON STA” .

  *                 ------------------     *                  ApStaDisabledState     *                   ------------------     *                     /      \     *   -> Turn ON STA   /        \ Turn on SAP <-     *                   /          \     *                  /            \     *         ---------------     --------------     *         StaEnabledState     ApEnabledState     *         ---------------     --------------     *                 \               /     *                  \             /     *    -> Turn ON SAP \           /  Turn on STA <-     *                    \         /     *                   ---------------     *                   QcApStaEnablingState     *                   ---------------     *                        |     |     *                        |     |     * -> CMD_AP_STARTED      |     |    CMD_STA_STARTED <-     *(SAP turn on completed) |     |    (STA turn on completed)     *                        |     |     *                  ---------------------     *                   QcApStaEnabledState     *                  ----------------------     *                         /  \                              /    \     * -> Turn on OFF STA    /      \     Turn OFF SAP     *                      /        \     *                 ------------------------     *                  QcApStaDisablingState     *                 ------------------------     *                           /\     *                          /  \     * -> CMD_WIFI_DISABLED    /    \    CMD_AP_STOPPED <-     *(STA turn OFF completed)/      \   (SAP turn OFF completed)     *                       /        \     *                      /          \     *      -------------------      -------------     *         ApEnabledState      StaEnabledState     *      -------------------      ---------------

6.1 ApStaDisabledState 状态下，不对CMD_WIFI_TOGGLED消息处理

6.2 转向StaEnabledState状态，在该状态的enter()函数中启动supplicant， processMessage中会根据扫描、sta/ap共存等条件做相应的状态处理。

class StaEnabledState extends State

enter()

mWifiStateMachine.setSupplicantRunning(true);

public boolean processMessage(Message msg)

case CMD_WIFI_TOGGLED:

7. frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiStateMachine.java

public void setSupplicantRunning(boolean enable)

sendMessage(CMD_START_SUPPLICANT);

8. frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiStateMachine.java

又是状态机，这里简单给出wifi状态机的各状态及结构。感觉有必要专门讲一下状态机。

WifiStateMachine state:

|- DefaultState

|-- InitialState

|-- SupplicantStartingState

|-- SupplicantStartedState

|--- ScanModeState

|--- ConnectModeState

|---- L2ConnectedState

|----- ObtainingIpState

|----- ConnectedState

|----- RoamingState

|---- DisconnectingState

|---- DisconnectedState

|---- WpsRunningState

|---- FilsState

|--- WaitForP2pDisableState

|-- SupplicantStoppingState

|-- SoftApstate

InitialState状态中处理消息：CMD_START_SUPPLICANT, 做加载驱动、启动supplicant操作，然后转向SupplicantStartingState状态。

class InitialState extends State

case CMD_START_SUPPLICANT:

mClientInterface = mWifiNative.setupForClientMode(); // loadDriver

mWifiNative.enableSupplicant() // start supplicant

transitionTo(mSupplicantStartingState);

9. frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiNative.java

public IClientInterface setupForClientMode()

startHalIfNecessary(true)) // start Hal

IClientInterface iClientInterface = mWificondControl.setupDriverForClientMode();

//启动Hal层。如果支持STA/AP共存，startConcurrentVendorHal；如果不支持共存：isStaMode=true启动sta模式，isStaMode=false启动ap模式。

private boolean startHalIfNecessary(boolean isStaMode)

if (mStaAndAPConcurrency)

// start ap & sta Concurrent Hal

return mWifiVendorHal.startConcurrentVendorHal(isStaMode);

return mWifiVendorHal.startVendorHal(isStaMode); // start Hal. Here

10. 不同于android N，wifinative会调用JNI层com_android_server_wifi_WifiNative.cpp. Android O在framework增加了调用Hal层的相关接口及hal设备管理接口。

frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiVendorHal.java

public boolean startVendorHal(boolean isStaMode)

mHalDeviceManager.start() //start wifi vendor hal

mIWifiStaIface = mHalDeviceManager.createStaIface(null, null); //loadDriver

11. 这个代码跟的有些凌乱

frameworks/opt/net/wifi/service/java/com/android/server/wifi/HalDeviceManager.java

public IWifiStaIface createStaIface(InterfaceDestroyedListener destroyedListener,

Looper looper) {

return (IWifiStaIface) createIface(IfaceType.STA, destroyedListener, looper);

}

private IWifiIface createIface(int ifaceType, InterfaceDestroyedListener destroyedListener, Looper looper)

IWifiIface iface = createIfaceIfPossible(chipInfos, ifaceType, destroyedListener, looper);

private IWifiIface createIfaceIfPossible(WifiChipInfo[] chipInfos, int ifaceType, InterfaceDestroyedListener destroyedListener, Looper looper)

IWifiIface iface = executeChipReconfiguration(bestIfaceCreationProposal, ifaceType);

private IWifiIface executeChipReconfiguration(IfaceCreationData ifaceCreationData, int ifaceType)

WifiStatus status = ifaceCreationData.chipInfo.chip.configureChip(ifaceCreationData.chipModeId);

12. Android O不在使用之前版本的JNI com_android_server_wifi_WifiNative.cpp。而是用HIDL，其实现在/hardware/interfaces/.

hardware/interfaces/wifi/1.1/default/wifi_chip.cpp

Return WifiChip::configureChip(ChipModeId mode_id, configureChip_cb hidl_status_cb)

return validateAndCall(this, WifiStatusCode::ERROR_WIFI_CHIP_INVALID, &WifiChip::configureChipInternal, hidl_status_cb, mode_id);

WifiStatus WifiChip::configureChipInternal(ChipModeId mode_id)

WifiStatus status = handleChipConfiguration(mode_id);

WifiStatus WifiChip::handleChipConfiguration(ChipModeId mode_id)

if (mode_id == kStaChipModeId) {

success = mode_controller_.lock()->changeFirmwareMode(IfaceType::STA);

} else {

success = mode_controller_.lock()->changeFirmwareMode(IfaceType::AP);

}

13. hardware/interfaces/wifi/1.0/default/wifi_mode_controller.cpp

bool WifiModeController::changeFirmwareMode(IfaceType type)

driver_tool_->LoadDriver()

driver_tool_->ChangeFirmwareMode(convertIfaceTypeToFirmwareMode(type))

14. 最后调到hal层，android O的hal层也进行了重写。位置也从之前的版本中的hardware/libhardware_legacy/wifi/移到了frameworks/opt/net/wifi/libwifi_hal/

frameworks/opt/net/wifi/libwifi_hal/driver_tool.cpp

bool DriverTool::LoadDriver()

return ::wifi_load_driver() == 0;

15 frameworks/opt/net/wifi/libwifi_hal/wifi_hal_common.cpp

int wifi_load_driver()

if (is_wifi_driver_loaded()) return 0;

insmod(DRIVER_MODULE_PATH, DRIVER_MODULE_ARG)

除了一些打开wifi时的消息通知、广播、状态变化，这里没有详细描述；至此，wifi打开的相关工作已经完成。

Qcom平台把加载wifi驱动的动作放在了开机时，在init.target.rc文件中：

insmod /vendor/lib/modules/qca_cld3_wlan.ko

根据实际情况，可能需要将开机加载驱动改为原来的动态加载。只需要做两处改动：

A. init脚本中删除加载wlan driver的行

B. 确认如下几个宏是打开和正确定义，在产品平台对应的makefile文件中加入即可：

WIFI_DRIVER_MODULE_PATH := "/vendor/lib/modules/wlan.ko"

WIFI_DRIVER_MODULE_NAME := "wlan"

WIFI_DRIVER_MODULE_ARG := ""

一. Android O wifi 架构：

二. 函数调用流程：

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