android reboot process

1. frameworks/base/core/java/android/os/Power.java  android_os_Power_reboot()
2. frameworks/base/core/jni/android_os_Power.cpp 
   reboot()
3. bionic/libc/unistd/reboot.c
   reboot(__reboot)
4. bionic/libc/arch-arm/syscalls/__reboot.S
5. kernel/arch/sh/kernel/reboot.c
   struct machine_ops machine_ops = {
       .power_off  = native_machine_power_off,
       .shutdown   = native_machine_shutdown,
       .restart    = native_machine_restart,
       .halt       = native_machine_halt,
   }
6. bionic/libc/include/sys/linux-syscalls.h
   #define __NR_reboot                       (__NR_SYSCALL_BASE + 88)
7. ./arch/arm/kernel/calls.S
   __NR_reboot 就是系统函数sys_reboot
8. ./kernel/sys.c
   
   kernel_restart
   {
         kernel_restart_prepare(cmd);  
       if (!cmd)
           printk(KERN_EMERG "Restarting system.\n");
       else
           printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
       kmsg_dump(KMSG_DUMP_RESTART); 
       machine_restart(cmd);
   
   }
   
   void kernel_restart_prepare(char *cmd)
   {
       blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
       system_state = SYSTEM_RESTART;
       usermodehelper_disable();
       device_shutdown();
       syscore_shutdown();
   }
   
   void kernel_power_off(void)
   {
       kernel_shutdown_prepare(SYSTEM_POWER_OFF);
       if (pm_power_off_prepare)
           pm_power_off_prepare();
       disable_nonboot_cpus();
       syscore_shutdown();
       printk(KERN_EMERG "Power down.\n");
       kmsg_dump(KMSG_DUMP_POWEROFF);
       machine_power_off();
   }
   
   
   
9. kernel/arch/arm/kernel/process.c
   void machine_shutdown(void)
   {
   #ifdef CONFIG_SMP
       smp_send_stop();
   #endif
   }
   
   void machine_halt(void)
   {
       machine_shutdown();
       while (1);
   }
   
   void machine_power_off(void)
   {
       machine_shutdown();
       if (pm_power_off)
           pm_power_off();
   }
   
   void machine_restart(char *cmd)
   {
       machine_shutdown();
       arm_pm_restart(reboot_mode, cmd);
   }
10. If you would like to trace power_off
    kernel/driver/mfd/xxxx_poweroff.c
    You will see:
    pm_power_off=xxxx_poweroff
11.