2010年10月12日星期二

[Android] Startup

1. Boot Code (in Chip)
  *Configure Chip: CPU, UART, Memory, (SD), Interrupt controller, watchdog, ...
  *Download Boot Loader into Memory (Internal SRAM or external DRAM)
2. Boot Loader (e.g., U-boot)
  *Initialize Source Sevice: NAND, SD, NOR, USB, Ethernet, ...
  *Initialize Target memory: DRAM, ...
  *Setup file system, network support, memory protections and security options, ...
  *Download kernel & application images from source storage to target memory
3. Linux Kernel
  *Set up interrupt controllers, MMU memory protections, caches and scheduling.
4. Android Init
 
  4.1 Entry Point main() in ~/android/system/core/init/init.c
  4.1.1 Clear the umask
  4.1.2 Setup the basic filesystem (/dev, /proc, /sys)
  4.1.3 Creates device nodes for kmsg and null (not /)
  4.1.4 Initialize Log
  4.1.5 Parse init.rc
  4.1.6 Pull the kernel commandline and ramdisk properties file in
  4.1.7 Parse hardware platform init.xxx.rc

  4.1.8 Trigger "early-init"
  4.1.9 device_init();
  4.1.10 property_init();
  4.1.11 Listen for keychords
  4.1.12 Open console
  4.1.13 Show "Android" by load_565rle_image(INIT_IMAGE_FILE)
  4.1.14 property_set("ro.xxx", ...);
  4.1.15 Trigger "init" (refer to init.rc)
  4.1.16 start_property_service();
  4.1.17 Create a signalling mechanism for the sigchld handler
  4.1.18 Trigger "early-boot"
  4.1.19 Trigger "boot" (refer to init.rc)
  4.1.20 Run all property triggers
  4.1.21 Register file descriptors with polling events

  4.1.22 Infinite Loop
  4.1.22.1  restart_processes() if needed
  4.1.22 .2 Poll registered file descriptors
  4.1.22 .3 Handle revents

  4.2 Start Services in ~/android/system/core/rootdir/init.rc
    *Services: console, adbd, servicemanager,  vold, netd, debuggerd, ril-daemon, zygote,  media, bootanim, dbus, bluetoothd, hfag, opush, pbap, installd, flash_recovery, racoon, mtpd, keystore, dumpstate
    *See the following 
root@android:/ # ps
USER     PID   PPID  VSIZE  RSS     WCHAN    PC         NAME
root      1     0     296    204   c009b74c 0000caac S /init
root      2     0     0      0     c004e72c 00000000 S kthreadd
root      3     2     0      0     c003fdc8 00000000 S ksoftirqd/0
root      4     2     0      0     c004b2c4 00000000 S events/0
root      5     2     0      0     c004b2c4 00000000 S khelper
root      6     2     0      0     c004b2c4 00000000 S suspend
root      7     2     0      0     c004b2c4 00000000 S kblockd/0
root      8     2     0      0     c004b2c4 00000000 S cqueue
root      9     2     0      0     c018179c 00000000 S kseriod
root      10    2     0      0     c004b2c4 00000000 S kmmcd
root      11    2     0      0     c006fc74 00000000 S pdflush
root      12    2     0      0     c006fc74 00000000 S pdflush
root      13    2     0      0     c00744e4 00000000 S kswapd0
root      14    2     0      0     c004b2c4 00000000 S aio/0
root      22    2     0      0     c017ef48 00000000 S mtdblockd
root      23    2     0      0     c004b2c4 00000000 S kstriped
root      24    2     0      0     c004b2c4 00000000 S hid_compat
root      25    2     0      0     c004b2c4 00000000 S rpciod/0
root      26    1     728    404   c0025d68 afd0e56c S /system/bin/sh
system    27    1     836    264   c01a94a4 afd0dd3c S /system/bin/servicemanager
root      28    1     3760   528   ffffffff afd0e3ac S /system/bin/vold
root      29    1     3736   516   ffffffff afd0e3ac S /system/bin/netd
root      30    1     700    268   c01b52b4 afd0e6cc S /system/bin/debuggerd
radio     31    1     3356   656   ffffffff afd0e3ac S /system/bin/rild
nobody    32    1     63140  22560 00000000 8021c5f8 R zygote
media     33        19852  3724  ffffffff afd0dd3c S /system/bin/mediaserver
bluetooth 34    1     1288   600   c009b74c afd0eb7c S /system/bin/dbus-daemon
root      35        832    276   c01b52b4 afd0e6cc S /system/bin/installd
keystore  36    1     1644   404   c01b52b4 afd0e6cc S /system/bin/keystore
root      37    1     724    372   c0025d68 afd0e56c S /system/bin/sh
root      38        852    336   c00b8fec afd0eafc S /system/bin/qemud
root      40    1     1320   152   ffffffff 0000ee04 S /sbin/adbd
root      56    37    820    272   c02181f4 afd0da9c S /system/bin/qemu-props
root      64    26    924    348   00000000 afd0da9c R ps


  *kthreadd: Linex kernel thread daemon
  4.3 Zygote: Start a Dalvik VM instance and System Server.
            In ~/android/frameworks/base/cmds/app_process/app_main.cpp:
            runtime.start("com.android.internal.os.ZygoteInit",
                startSystemServer); 

            In  ~/android/frameworks/base/core/jni/AndroidRuntime.cpp:
           void AndroidRuntime::start(const char* className, const bool startSystemServer)
           if (startVm(&mJavaVM, &env) != 0)
            In ~/android/frameworks/base/services/java/com/android/server/SystemServer.java:
            startSystemServer();  4.3.1 Dalvik VM
  4.3.2 System Server: Add Critical System Services
          In ~/android/frameworks/base/services/java/com/android/server/SystemServer.java
        // Critical services...
        try {
            Slog.i(TAG, "Entropy Service");
            ServiceManager.addService("entropy", new EntropyService());

            Slog.i(TAG, "Power Manager");
            power = new PowerManagerService();
            ServiceManager.addService(Context.POWER_SERVICE, power);

            Slog.i(TAG, "Activity Manager");
            context = ActivityManagerService.main(factoryTest);

            Slog.i(TAG, "Telephony Registry");
            ServiceManager.addService("telephony.registry", new TelephonyRegistry(context));

            AttributeCache.init(context);
            Slog.i(TAG, "Package Manager");
            pm = PackageManagerService.main(context,
                    factoryTest != SystemServer.FACTORY_TEST_OFF);

            ActivityManagerService.setSystemProcess();
            mContentResolver = context.getContentResolver();
            // The AccountManager must come before the ContentService
            try {
                Slog.i(TAG, "Account Manager");
                ServiceManager.addService(Context.ACCOUNT_SERVICE,
                        new AccountManagerService(context));
            } catch (Throwable e) {
                Slog.e(TAG, "Failure starting Account Manager", e);
            }

            Slog.i(TAG, "Content Manager");
            ContentService.main(context,
                    factoryTest == SystemServer.FACTORY_TEST_LOW_LEVEL);
            Slog.i(TAG, "System Content Providers");
            ActivityManagerService.installSystemProviders();
            Slog.i(TAG, "Battery Service");
            battery = new BatteryService(context);
            ServiceManager.addService("battery", battery);
            Slog.i(TAG, "Lights Service");
            lights = new LightsService(context);
            Slog.i(TAG, "Vibrator Service");
            ServiceManager.addService("vibrator", new VibratorService(context));
            // only initialize the power service after we have started the
            // lights service, content providers and the battery service.
            power.init(context, lights, ActivityManagerService.getDefault(), battery);
            Slog.i(TAG, "Alarm Manager");
            AlarmManagerService alarm = new AlarmManagerService(context);
            ServiceManager.addService(Context.ALARM_SERVICE, alarm);
            Slog.i(TAG, "Init Watchdog");
            Watchdog.getInstance().init(context, battery, power, alarm,
                    ActivityManagerService.self());
            // Sensor Service is needed by Window Manager, so this goes first
            Slog.i(TAG, "Sensor Service");
            ServiceManager.addService(Context.SENSOR_SERVICE, new SensorService(context));
            Slog.i(TAG, "Window Manager");
            wm = WindowManagerService.main(context, power,
                    factoryTest != SystemServer.FACTORY_TEST_LOW_LEVEL);
            ServiceManager.addService(Context.WINDOW_SERVICE, wm);
            ((ActivityManagerService)ServiceManager.getService("activity"))
                    .setWindowManager(wm);

5. Start-up Complete
  *Broadcast ACTION_BOOT_COMPLETED



[] http://hi.baidu.com/j_fo/blog/item/c782b11bbb16f1178618bf82.html
[]The Android boot process from power on
[] 如何去寫Android init.rc (Android init language)
[] http://source.android.com/porting/bring_up.html
[] http://blog.chinaunix.net/u2/87328/showart_1678365.html
[] Android Zygote Startup

沒有留言:

張貼留言