0.主要流程
usb插入通过传递cmdline给init解析从而启动充电进程
1. LK
lk\app\aboot\aboot.c
update_cmdline
----------
if (boot_into_ffbm) // 工厂测试模式
{
cmdline_len += strlen(androidboot_mode);
cmdline_len += strlen(ffbm_mode_string);
/* reduce kernel console messages to speed-up boot */
cmdline_len += strlen(loglevel);
}
else if (target_pause_for_battery_charge()) // 判断是否关机充电
{
pause_at_bootup = 1; // charger flag
cmdline_len += strlen(battchg_pause); //更新 cmd line 长度
}
----------
else if (pause_at_bootup) // charger flag
{
src = battchg_pause; // static const char *battchg_pause = " androidboot.mode=charger";
if (have_cmdline) --dst;
while ((*dst++ = *src++));
}
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2.init
#init.c
if (!is_ffbm)
is_charger = !strcmp(bootmode, "charger");
----------
if (is_charger)
action_for_each_trigger("charger", action_add_queue_tail);
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# init.rc
on charger
class_start charger
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# init.qcom.rc
service charger /charger
class charger
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#system/core/healthd/Android.mk
LOCAL_MODULE := healthd
...
# Symlink /charger to /sbin/healthd
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