代码路径：
frameworks/base/core/java/android/os/ILedService.aidl
out/target/common/obj/JAVA_LIBRARIES/framework_intermediates/core/java/android/os/ILedService.java
frameworks/base/services/core/java/com/android/server/LedService.java
frameworks/base/services/java/com/android/server/SystemServer.java
frameworks/base/services/core/jni/onload.cpp
frameworks/base/services/core/jni/com_android_server_LedService.cpp
frameworks/base/services/core/jni/Android.mk
hardware/libhardware/include/hardware/led_hal.h
hardware/libhardware/modules/led/led_hal.c
hardware/libhardware/modules/led/Android.mk
hardware/libhardware/modules/Android.mk
outtargetcommonobjJAVA_LIBRARIESframework_intermediatesclasses.jar
一、创建AIDL
1、创建一个ILedService.aidl文件，在该文件中写入如下内容。
package android.os;
interface ILedService
{
int ledCtrl(int which, int status);
}
2、将编写好的ILedService.aidl文件放到frameworks/base/core/java/android/os下面
3、将添加的ILedService.aidl文件在Android.mk文件中参与编译，在frameworks/base/Android.mk 添加一行
LOCAL_SRC_FILES += core/java/android/os/IVibratorService.aidl + core/java/android/os/ILedService.aidl
4、然后执行如下命令来编译frameworks模块
mmm frameworks/base 或者mma frameworks/base mmm frameworks/base/core/res
最终编译的目标模块是：framework.jar
编译生成的文件的路径
out/target/common/obj/JAVA_LIBRARIES/framework_intermediates/core/java/android/os/ILedService.java
ILedService.java内容如下所示
package android.os;
public interface ILedService extends android.os.IInterface
{
public static abstract class Stub extends android.os.Binder implements android.os.ILedService
{
private static final java.lang.String DEscriptOR = "android.os.ILedService";
public Stub()
{
this.attachInterface(this, DEscriptOR);
}
public static android.os.ILedService asInterface(android.os.IBinder obj)
{
if ((obj==null)) {
return null;
}
android.os.IInterface iin = obj.queryLocalInterface(DEscriptOR);
if (((iin!=null)&&(iin instanceof android.os.ILedService))) {
return ((android.os.ILedService)iin);
}
return new android.os.ILedService.Stub.Proxy(obj);
}
@Override public android.os.IBinder asBinder()
{
return this;
}
@Override public boolean onTransact(int code, android.os.Parcel data, android.os.Parcel reply, int flags) throws android.os.RemoteException
{
switch (code)
{
case INTERFACE_TRANSACTION:
{
reply.writeString(DEscriptOR);
return true;
}
case TRANSACTION_ledCtrl:
{
data.enforceInterface(DEscriptOR);
int _arg0;
_arg0 = data.readInt();
int _arg1;
_arg1 = data.readInt();
int _result = this.ledCtrl(_arg0, _arg1);
reply.writeNoException();
reply.writeInt(_result);
return true;
}
}
return super.onTransact(code, data, reply, flags);
}
private static class Proxy implements android.os.ILedService
{
private android.os.IBinder mRemote;
Proxy(android.os.IBinder remote)
{
mRemote = remote;
}
@Override public android.os.IBinder asBinder()
{
return mRemote;
}
public java.lang.String getInterfaceDescriptor()
{
return DEscriptOR;
}
@Override public int ledCtrl(int which, int status) throws android.os.RemoteException
{
android.os.Parcel _data = android.os.Parcel.obtain();
android.os.Parcel _reply = android.os.Parcel.obtain();
int _result;
try {
_data.writeInterfaceToken(DEscriptOR);
_data.writeInt(which);
_data.writeInt(status);
mRemote.transact(Stub.TRANSACTION_ledCtrl, _data, _reply, 0);
_reply.readException();
_result = _reply.readInt();
}
finally {
_reply.recycle();
_data.recycle();
}
return _result;
}
}
static final int TRANSACTION_ledCtrl = (android.os.IBinder.FIRST_CALL_TRANSACTION + 0);
}
public int ledCtrl(int which, int status) throws android.os.RemoteException;
}
备注：添加过程中使用mmm可能会编译报错，如果报错就执行mma，然后再执行mmm就可以编译通过了
二、创建Server
1、创建一个服务端LedService.java文件，内容如下所示
package com.android.server;
import android.os.ILedService;
public class LedService extends ILedService.Stub {
private static final String TAG = "LedService";
public int ledCtrl(int which, int status) throws android.os.RemoteException
{
return native_ledCtrl(which, status);
}
public LedService() {
native_ledOpen();
}
public static native int native_ledOpen();
public static native void native_ledClose();
public static native int native_ledCtrl(int which, int status);
}
2、将LedService.java文件添加到该目录下面frameworks/base/services/core/java/com/android/server/
在SystemServer.java文件中startOtherServices()方法中添加启动LedService服务
private void startOtherServices() {
final Context context = mSystemContext;
VibratorService vibrator = null;
IStorageManager storageManager = null;
NetworkManagementService networkManagement = null;
NetworkStatsService networkStats = null;
NetworkPolicyManagerService networkPolicy = null;
ConnectivityService connectivity = null;
NetworkScoreService networkScore = null;
NsdService serviceDiscovery= null;
WindowManagerService wm = null;
SerialService serial = null;
NetworkTimeUpdateService networkTimeUpdater = null;
CommonTimeManagementService commonTimeMgmtService = null;
InputManagerService inputManager = null;
TelephonyRegistry telephonyRegistry = null;
ConsumerIrService consumerIr = null;
MmsServiceBroker mmsService = null;
HardwarePropertiesManagerService hardwarePropertiesService = null;
ConnectivityServiceEx connectivityEx = null;
//Bug 692795 PowerGuruService powerguru --> BEG
AbsPowerGuruService powerguru = null;
//Bug 692795 PowerGuruService powerguru --> END
PowerController powerctl = null;
+ Slog.i(TAG, "Led Service");
+ ServiceManager.addService("led", new LedService());
}
添加启动服务代码后，就执行如下命令编译出services.jar
mmm frameworks/base/services
最终编译的目标模块是：services.jar
备注：在services目录下面不需要把LedService.java添加进去，因为它的内容里已经把该目录下所有JAVA文件自动包含进去了，如下所示
LOCAL_SRC_FILES := $(call all-java-files-under,java)
三、创建JNI
1、创建一个com_android_server_LedService.cpp文件，在该文件中编写如下内容
#define LOG_TAG "LedService" #include "jni.h" #include "JNIHelp.h" #include "android_runtime/AndroidRuntime.h" #include#include #include #include #include #include #include #include #include namespace android { static led_device_t* led_device; jint ledOpen(JNIEnv *env, jobject cls) { jint err; hw_module_t* module; hw_device_t* device; ALOGI("native ledOpen ..."); err = hw_get_module("led", (hw_module_t const**)&module); if (err == 0) { err = module->methods->open(module, NULL, &device); if (err == 0) { led_device = (led_device_t *)device; return led_device->led_open(led_device); } else { return -1; } } return -1; } void ledClose(JNIEnv *env, jobject cls) { //ALOGI("native ledClose ..."); //close(fd); } jint ledCtrl(JNIEnv *env, jobject cls, jint which, jint status) { ALOGI("native ledCtrl %d, %d", which, status); return led_device->led_ctrl(led_device, which, status); } static const JNINativeMethod methods[] = { {"native_ledOpen", "()I", (void *)ledOpen}, {"native_ledClose", "()V", (void *)ledClose}, {"native_ledCtrl", "(II)I", (void *)ledCtrl}, }; int register_android_server_LedService(JNIEnv *env) { return jniRegisterNativeMethods(env, "com/android/server/LedService", methods, NELEM(methods)); } }
2、在onload.cpp文件中注册register_android_server_LedService服务
namespace android {
int register_android_server_AlarmManagerService(JNIEnv* env);
int register_android_server_BatteryStatsService(JNIEnv* env);
int register_android_server_ConsumerIrService(JNIEnv *env);
int register_android_server_InputApplicationHandle(JNIEnv* env);
int register_android_server_InputWindowHandle(JNIEnv* env);
int register_android_server_InputManager(JNIEnv* env);
int register_android_server_LightsService(JNIEnv* env);
int register_android_server_PowerManagerService(JNIEnv* env);
int register_android_server_storage_AppFuse(JNIEnv* env);
int register_android_server_SerialService(JNIEnv* env);
int register_android_server_SystemServer(JNIEnv* env);
int register_android_server_UsbDeviceManager(JNIEnv* env);
int register_android_server_UsbMidiDevice(JNIEnv* env);
int register_android_server_UsbHostManager(JNIEnv* env);
int register_android_server_vr_VrManagerService(JNIEnv* env);
int register_android_server_VibratorService(JNIEnv* env);
int register_android_server_location_ContextHubService(JNIEnv* env);
int register_android_server_location_GnssLocationProvider(JNIEnv* env);
int register_android_server_connectivity_Vpn(JNIEnv* env);
int register_android_server_connectivity_tethering_OffloadHardwareInterface(JNIEnv*);
int register_android_server_hdmi_HdmiCecController(JNIEnv* env);
int register_android_server_tv_TvUinputBridge(JNIEnv* env);
int register_android_server_tv_TvInputHal(JNIEnv* env);
int register_android_server_PersistentDataBlockService(JNIEnv* env);
int register_android_server_Watchdog(JNIEnv* env);
int register_android_server_HardwarePropertiesManagerService(JNIEnv* env);
int register_android_server_SyntheticPasswordManager(JNIEnv* env);
int register_android_server_GraphicsStatsService(JNIEnv* env);
int register_android_hardware_display_DisplayViewport(JNIEnv* env);
int register_android_server_ShutdownThread(JNIEnv* env);
+int register_android_server_LedService(JNIEnv *env);
};
using namespace android;
extern "C" jint JNI_onLoad(JavaVM* vm, void* )
{
JNIEnv* env = NULL;
jint result = -1;
if (vm->GetEnv((void**) &env, JNI_VERSION_1_4) != JNI_OK) {
ALOGE("GetEnv failed!");
return result;
}
ALOG_ASSERT(env, "Could not retrieve the env!");
register_android_server_broadcastradio_BroadcastRadioService(env);
register_android_server_broadcastradio_Tuner(vm, env);
register_android_server_PowerManagerService(env);
register_android_server_SerialService(env);
register_android_server_InputApplicationHandle(env);
register_android_server_InputWindowHandle(env);
register_android_server_InputManager(env);
register_android_server_LightsService(env);
register_android_server_AlarmManagerService(env);
register_android_server_UsbDeviceManager(env);
register_android_server_UsbMidiDevice(env);
register_android_server_UsbHostManager(env);
register_android_server_vr_VrManagerService(env);
register_android_server_VibratorService(env);
register_android_server_SystemServer(env);
register_android_server_location_ContextHubService(env);
register_android_server_location_GnssLocationProvider(env);
register_android_server_connectivity_Vpn(env);
register_android_server_connectivity_tethering_OffloadHardwareInterface(env);
register_android_server_ConsumerIrService(env);
register_android_server_BatteryStatsService(env);
register_android_server_hdmi_HdmiCecController(env);
register_android_server_tv_TvUinputBridge(env);
register_android_server_tv_TvInputHal(env);
register_android_server_PersistentDataBlockService(env);
register_android_server_Watchdog(env);
register_android_server_HardwarePropertiesManagerService(env);
register_android_server_storage_AppFuse(env);
register_android_server_SyntheticPasswordManager(env);
register_android_server_GraphicsStatsService(env);
register_android_hardware_display_DisplayViewport(env);
register_android_server_ShutdownThread(env);
+ register_android_server_LedService(env);
return JNI_VERSION_1_4;
}
3、将刚编写的com_android_server_LedService.cpp文件，在Android.mk文件中添加该文件编译到libandroid_servers.so.toc中去
$(LOCAL_REL_DIR)/com_android_server_VibratorService.cpp + $(LOCAL_REL_DIR)/com_android_server_LedService.cpp
4、编译命令
mmm frameworks/base/services
编译生成的文件
out/target/product//obj/SHARED_LIBRARIES/libandroid_servers_intermediates/libandroid_servers.so.toc
四、创建HAL
1、创建led_hal.h文件，内容如下所示
#ifndef ANDROID_LED_INTERFACE_H #define ANDROID_LED_INTERFACE_H #include#include #include #include __BEGIN_DECLS struct led_device_t { struct hw_device_t common; int (*led_open)(struct led_device_t* dev); int (*led_ctrl)(struct led_device_t* dev, int which, int status); }; __END_DECLS #endif // ANDROID_LED_INTERFACE_H
2、将led_hal.h文件拷贝到该目录下面：hardwarelibhardwareincludehardware
3、hardware/libhardware/modules/在该目录下面创建led目录，在该目录下面创建led_hal.c文件
#define LOG_TAG "LedHal" #include#include #include #include #include #include #include #include #include #include #include #include #include #include static int fd; static int led_close(struct hw_device_t* device) { close(fd); return 0; } static int led_open(struct led_device_t* dev) { fd = open("/dev/leds", O_RDWR); ALOGI("led_open : %d", fd); if (fd >= 0) return 0; else return -1; } static int led_ctrl(struct led_device_t* dev, int which, int status) { int ret = ioctl(fd, status, which); ALOGI("led_ctrl : %d, %d, %d", which, status, ret); return ret; } static struct led_device_t led_dev = { .common = { .tag = HARDWARE_DEVICE_TAG, .close = led_close, }, .led_open = led_open, .led_ctrl = led_ctrl, }; static int led_device_open(const struct hw_module_t* module, const char* id, struct hw_device_t** device) { *device = &led_dev; return 0; } static struct hw_module_methods_t led_module_methods = { .open = led_device_open, }; struct hw_module_t HAL_MODULE_INFO_SYM = { .tag = HARDWARE_MODULE_TAG, .id = "led", .methods = &led_module_methods, };
4、hardware/libhardware/modules/在该目录下面创建led目录，在该目录下面创建Android.mk文件
LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := led.default # HAL module implementation stored in # hw/.default.so LOCAL_MODULE_RELATIVE_PATH := hw LOCAL_C_INCLUDES := hardware/libhardware LOCAL_SRC_FILES := led_hal.c LOCAL_SHARED_LIBRARIES := liblog include $(BUILD_SHARED_LIBRARY)
5、hardware/libhardware/modules/目录下面的Android.mk中添加led模块
hardware_modules :=
audio_remote_submix
camera
gralloc
hwcomposer
input
radio
sensors
thermal
usbaudio
usbcamera
vehicle
led
vr
include $(call all-named-subdir-makefiles,$(hardware_modules))
6、编译命令
mmm hardware/libhardware/modules/led
编译生成的的文件
目标文件：out/target/product/sl8541e_cus_go/system/lib/hw/led.default.so 中间文件：out/target/product/sl8541e_cus_go/obj/SHARED_LIBRARIES/led.default_intermediates/led.default.so.toc
日志打印：
12-28 14:46:00.576 2550 2550 I LedService: native ledOpen ... 12-28 14:46:00.577 2550 2550 I LedHal : led_open : -1
备注说明：参考韦东山老师写的
