Android Restart reason mechanism

Reprint: http://blog.csdn.net/linux_devices_driver/article/details/17928663

Reboot Pass Parameters , making the boot into the fixed mode of the parameter (usually with our familiar bootloader and recovery , etc.), essentially in kernel shutdown is called to restart,

Write the mode value to the share memory , then in the boot bootloader stage, then read the memory,boot into the specified mode, if the match does not get up the normal boot, The following is the posted code;

Restart 2 different ways:

A:android_reboot (android_rb_restart2, 0, "rtcalarm");//Enter RTC Alarm mode

B:ADB reboot bootloader,adb reboot recovery; into our familiar bootloader and recorevy patterns.

RESTAR.C:

void*Restart_reason;/*function will be assigned to machine restart pointer*/voidMsm_restart (CharModeConst Char*cmd) {#ifdef Config_msm_dload_mode/*This looks is a normal reboot at this point.*/Set_dload_mode (0); /*Write Download Mode flags If we ' re panic ' ing*/Set_dload_mode (in_panic);/*Write Download Mode flags if Restart_mode says so*/ if(Restart_mode = =restart_dload) {Set_dload_mode (1); #ifdef Config_lge_crash_handler Writel (0x6d63c421, Restart_reason); GotoReset;#endif } /*Kill Download mode if Master-kill switch is set*/ if(!download_mode) Set_dload_mode (0);#endifPRINTK (Kern_notice"going down for restart now\n"); Pm8xxx_reset_pwr_off (1); if(cmd! =NULL) {  if(!STRNCMP (CMD,"bootloader",Ten) {__raw_writel (0x77665500, Restart_reason); } Else if(!STRNCMP (CMD,"Recovery",8) {__raw_writel (0x77665502, Restart_reason); } Else if(!STRNCMP (CMD,"oem-",4) ) {unsignedLongCode; Code= Simple_strtoul (cmd +4Null -) &0xFF; __raw_writel (0x6f656d00|code, Restart_reason); } Else{__raw_writel (0x77665501, Restart_reason); } } Else{__raw_writel (0x77665501, Restart_reason); } #ifdef Config_lge_crash_handlerif(In_panic = =1) Set_kernel_crash_magic_number (); Reset:#endif/* Config_lge_crash_handler */__raw_writel (0, Msm_tmr0_base +wdt0_en); if(! (Machine_is_msm8x60_fusion () | |Machine_is_msm8x60_fusn_ffa ()))  {MB (); __raw_writel (0, PSHOLD_CTL_SU);/*actually reset the chip*/Mdelay ( the); Pr_notice ("Ps_hold didn ' t work, falling back to watchdog\n"); } __raw_writel (1, Msm_tmr0_base +Wdt0_rst); __raw_writel (5*0x31f3, Msm_tmr0_base +wdt0_bark_time); __raw_writel (0x31f3, Msm_tmr0_base +wdt0_bite_time); __raw_writel (1, Msm_tmr0_base +wdt0_en); Mdelay (10000); PRINTK (Kern_err"restarting has failed\n");}Static int__init Msm_restart_init (void) {#ifdef Config_msm_dload_mode atomic_notifier_chain_register (&panic_notifier_list, &panic_blk); Dload_mode_addr= Msm_imem_base +dload_mode_addr, #ifdef config_lge_crash_handler lge_error_handler_cookie_addr= Msm_imem_base +lge_error_handler_magic_addr;#endifSet_dload_mode (download_mode);#endifMsm_tmr0_base=msm_timer_get_timer0_base (); Restart_reason= Msm_imem_base + restart_reason_addr;//Restart_reason is assigned memory addressPm_power_off=Msm_power_off;return 0;}

Lk:init.c

/*LK reads the restart value written by kernel*/unsigned check_reboot_mode (void) {unsigned Restart_reason=0; void*RESTART_REASON_ADDR = (void*)0x2a05f65c; /*Read reboot reason and scrub it*/Restart_reason=Readl (RESTART_REASON_ADDR); Writel (0x00, RESTART_REASON_ADDR); returnRestart_reason;}#defineRecovery_mode 0x77665502#defineFastboot_mode 0x77665500#defineAdb_reboot_mode 0x77665501/*Check reboot mode*/Reboot_mode=Check_reboot_mode ();#ifConfig_charing_while_mechine_trun_off {  externUnsignedintCustom_power_on_charger (void); if(Custom_power_on_charger () && reboot_mode && (reboot_mode!=fastboot_mode) && (Reboot_mode! =Adb_reboot_mode)) Boot_into_recovery=1; dprintf (0,"[charger]%s () Custom_power_on_charger () =%x check_reboot_mode () =%0x\n", __func__, Custom_power_on_charger (), Reboot_mode); } #endif  if(Reboot_mode = =Recovery_mode) {Boot_into_recovery=1; } Else if(Reboot_mode = =Fastboot_mode) {  GotoFastBoot;}

so familiar with this mechanism, we can add their own mode, such as alarm mode, Factory mode and so on;

Android Restart reason mechanism