Android从上层到底层完整流程

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文档，从上层界面一直调用到内核的过程，最近同事跟我要，我看了下又在整理了下，纯属个人分析（不过都运行验证过），不对的请大牛指出。Alarm调用流程，alarm的流程实现了从上层应用一直到下面driver的调用流程，下面简单阐述：涉及代码;./packages/apps/DeskClock/src/com/android/deskclock/./frameworks/base/core/java/android/app/./frameworks/base/services/java/com/android/server/./frameworks/base/services/jni/./kernel/kernel/drivers/rtc/./kernel/kernel/include/linux/./kernel/kernel/drivers/rtc/./kernel/kernel/drivers/rtc/./kernel/kernel/drivers/rtc//packages/apps/DeskClock/src/com/android/deskclock/./kernel/arch/arm/configs/mmp2_android_defconfig./kernel/kernel/kernel/.config？点击Clock应用程序，然后设置新闹钟，会调到里面的publicstaticlongsetAlarm(Contextcontext,Alarmalarm){....setNextAlert(context);....}然后这里面也会调用到？publicstaticvoidsetNextAlert(finalContextcontext){if(!enableSnoozeAlert(context)){Alarmalarm=calculateNextAlert(context);.....,atTimeInMillis,sender);...}然后就调用到了里面方法publicvoidset(inttype,longtriggerAtTime,PendingIntentoperation){try{(type,triggerAtTime,operation);}catch(RemoteExceptionex){}}然后就调用到了里面方法publicvoidset(inttype,longtriggerAtTime,PendingIntentoperation){setRepeating(type,triggerAtTime,0,operation);}然后继续调用publicvoidsetRepeating(inttype,longtriggerAtTime,longinterval,PendingIntentoperation){.....synchronized(mLock){Alarmalarm=newAlarm();=type;=triggerAtTime;=interval;=operation;removeLocked(operation);if(localLOGV)(TAG,"set:"+alarm);intindex=addAlarmLocked(alarm);if(index==0){setLocked(alarm);}}}然后就调用到privatevoidsetLocked(Alarmalarm){.........}这里就调用到jni了privatenativevoidset(intfd,inttype,longseconds,longnanoseconds);这就调用到了里面staticJNINativeMethodsMethods[]={/*name,signature,funcPtr*/{"init","()I",(void*)android_server_AlarmManagerService_init},{"close","(I)V",(void*)android_server_AlarmManagerService_close},{"set","(IIJJ)V",(void*)android_server_AlarmManagerService_set},{"waitForAlarm","(I)I",(void*)android_server_AlarmManagerService_waitForAlarm},{"setKernelTimezone","(II)I",(void*)android_server_AlarmManagerService_setKernelTimezone},};set对应的是android_server_AlarmManagerService_set，具体是staticvoidandroid_server_AlarmManagerService_set(JNIEnv*env,jobjectobj,jintfd,jinttype,jlongseconds,jlongnanoseconds){#ifHAVE_ANDROID_OSstructtimespects;=seconds;=nanoseconds;？intresult=ioctl(fd,ANDROID_ALARM_SET(type),&ts);if(result<0){LOGE("Unabletosetalarmto%lld.%09lld:%s\n",seconds,nanoseconds,strerror(errno));}#endif}然后ioctl就调用到了staticlongalarm_ioctl(structfile*file,unsignedintcmd,unsignedlongarg){....caseANDROID_ALARM_SET(0):if(copy_from_user(&new_alarm_time,(void__user*)arg,sizeof(new_alarm_time))){rv=-EFAULT;gotoerr1;}from_old_alarm_set:spin_lock_irqsave(&alarm_slock,flags);pr_alarm(IO,"alarm%dset%ld.%09ld\n",alarm_type,,;alarm_enabled|=alarm_type_mask;alarm_start_range(&alarms[alarm_type],timespec_to_ktime(new_alarm_time),timespec_to_ktime(new_alarm_time));spin_unlock_irqrestore(&alarm_slock,flags);if(ANDROID_ALARM_BASE_CMD(cmd)!=ANDROID_ALARM_SET_AND_WAIT(0)&&cmd!=ANDROID_ALARM_SET_AND_WAIT_OLD)break;/*fallthough*/....caseANDROID_ALARM_SET_RTC:if(copy_from_user(&new_rtc_time,(void__user*)arg,sizeof(new_rtc_time))){rv=-EFAULT;gotoerr1;}rv=alarm_set_rtc(new_rtc_time);spin_lock_irqsave(&alarm_slock,flags);alarm_pending|=ANDROID_ALARM_TIME_CHANGE_MASK;wake_up(&alarm_wait_queue);spin_unlock_irqrestore(&alarm_slock,flags);if(rv<0)gotoerr1;break;....}然后这边就调用到了alarm_start_range设置闹钟，alarm_set_rtc设置RTC这两个函数在声明，在里实现。这是里面的声明voidalarm_start_range(structalarm*alarm,ktime_tstart,ktime_tend);intalarm_try_to_cancel(structalarm*alarm);intalarm_cancel(structalarm*alarm);ktime_talarm_get_elapsed_realtime(void);/*setrtcwhilepreservingelapsedrealtime*/intalarm_set_rtc(conststructtimespects);下面看里面实现：intalarm_set_rtc(structtimespecnew_time){....ret=rtc_set_time(alarm_rtc_dev,&rtc_new_rtc_time);....}里面实现了alarm_suspendalarm_resume函数，就是如果系统没有suspend的时候，设置闹钟并不会往rtc芯片的寄存器上写数据，因为不需要唤醒系统，所以闹钟数据时间什么的就通过上层写到设备文件/dev/alarm，里面就可以了，AlarmThread会不停的去轮寻下一个时间有没有闹钟，直接从设备文件/dev/alarm里面读取。第二种，系统要是进入susupend的话，alarm的alarm_suspend就会写到下层的rtc芯片的寄存器上去，然后即使系统suspend之后，闹钟通过rtc也能唤醒系统，这里就调用到了里面..err=rtc->ops->set_time(rtc->,tm);....}然后set_time就看到具体的是那个RTC芯片，这边我们是staticconststructrtc_class_opspcf8563_rtc_ops={.read_time=pcf8563_rtc_read_time,.set_time=pcf8563_rtc_set_time,.read_alarm=pcf8563_rtc_read_alarm,.set_alarm=pcf8563_rtc_set_alarm,};然后就到了staticintpcf8563_rtc_set_time(structdevice*dev,structrtc_time*tm){unsignedcharbuf[TIME_NUM];intret;ret=data_calc(buf,tm,TIME_NUM);if(ret<0)gotoout;ret=i2c_smbus_write_i2c_block_data(pcf8563_info->client,PCF8563_RTC_SEC,TIME_NUM,buf);kernel/kernel/kernel/.config查看，这边的pcf8563rtc是当前系统正在使用的芯片型号？#CONFIG_RTC_DRV_ISL1208isnotset#CONFIG_RTC_DRV_X1205isnotsetCONFIG_RTC_DRV_PCF8563=y#CONFIG_RTC_DRV_PCF8583isnotset#CONFIG_RTC_DRV_M41T80isnotset下面是系统唤醒之后，闹钟怎么工作的流程，简单阐述系统没有suspend的话直接走下面流程，如果suspend的话会被RTC唤醒，然后还是走下面的流程privateclassAlarmThreadextendsThread{publicAlarmThread(){super("AlarmManager");}？publicvoidrun(){while(true){intresult=waitForAlarm(mDescriptor);..Alarmalarm=();try{if(localLOGV)(TAG,"sendingalarm"+alarm);(,,mResultReceiver,mHandler);....}}}staticjintandroid_server_AlarmManagerService_waitForAlarm(JNIEnv*env,jobjectobj,jintfd){#ifHAVE_ANDROID_OSintresult=0;？do{result=ioctl(fd,ANDROID_ALARM_WAIT);}while(result<0&&errno==EINTR);？if(result<0){LOGE("Unabletowaitonalarm:%s\n",strerror(errno));return0;}？returnresult;#endif}AlarmManagerService里面有个AlarmThread会一直轮询/dev/alarm文件，如果打开失败就直接返回，成功就会做一些动作，比如查找时间最近的alarm，比如睡眠被闹钟唤醒的时候，这边就发一个intent出去，然后在里面弹出里面会收到就会调用下面的(alarmAlert);然后弹出alarm这个界面Classc=;其中publicclassAlarmAlertextendsAlarmAlertFullScreen所以系统睡眠之后被alarm唤醒弹出的alarm就是这边start的publicclassAlarmReceiverextendsBroadcastReceiver{/**IfthealarmisolderthanSTALE_WINDOW,ignore.Itisprobablytheresultofatimeortimezonechange*/privatefinalstaticintSTALE_WINDOW=30*60*1000;@OverridepublicvoidonReceive(Contextcontext,Intentintent){.........IntentalarmAlert=newIntent(context,c);,alarm);|;(alarmAlert);........}到这里alarm就显示出来了我个人添加的log，验证了流程，suspend和不suspend的时候alarm的区别跟上面说的一样