QCOM平台子系统通过AP处理异常

子系统发生异常时，是如何通过中断通知ＡＰ主系统？

AP主系统在kernel代码中subsystem_restart.c 提供子系统中断注册接口：subsys_register。

比如，为modem子系统注意异常中断注册：

static int pil_subsys_init(struct modem_data *drv,
struct platform_device *pdev)

{
int ret;

drv->subsys_desc.name = "modem";
drv->subsys_desc.dev = &pdev->dev;
drv->subsys_desc.owner = THIS_MODULE;
drv->subsys_desc.shutdown = modem_shutdown;
drv->subsys_desc.powerup = modem_powerup;
drv->subsys_desc.ramdump = modem_ramdump;
drv->subsys_desc.crash_shutdown = modem_crash_shutdown;
drv->subsys_desc.err_fatal_handler = modem_err_fatal_intr_handler;
drv->subsys_desc.stop_ack_handler = modem_stop_ack_intr_handler;
drv->subsys_desc.wdog_bite_handler = modem_wdog_bite_intr_handler;

drv->subsys = subsys_register(&drv->subsys_desc);

子系统异常中断发生时，AP主系统相应的irq handler被调用。

异常中断重启，分为两个级别：

static const char * const restart_levels[] = {             　　（subsystem_restart.c ）
[RESET_SOC] = "SYSTEM",
[RESET_SUBSYS_COUPLED] = "RELATED",

};

处理级别，可能过restart_level_store函数提供的sys接口修改，比如：

    write /sys/module/msm_poweroff/parameters/emergent_restart 1

    write /sys/module/msm_poweroff/parameters/download_mode 1

    write /sys/bus/msm_subsys/devices/subsys0/restart_level system

    write /sys/bus/msm_subsys/devices/subsys1/restart_level system

    write /sys/bus/msm_subsys/devices/subsys2/restart_level related

/proprietary/ss-restart/subsystem_ramdump/subsystem_ramdump.c

qcom/common/rootdir/etc/init.qcom.rc:service ss_ramdump /system/bin/subsystem_ramdump

这个service启动后会收集子系统的 ramdumps and logs .