/*
   * poweroff.c - sysrq handler to gracefully power down machine.
   *
   * This file is released under the GPL v2
   */
  
  #include <linux/kernel.h>
  #include <linux/sysrq.h>
  #include <linux/init.h>
  #include <linux/pm.h>
  #include <linux/workqueue.h>

  #include <linux/reboot.h>

  #include <linux/cpumask.h>

  
  /*
   * When the user hits Sys-Rq o to power down the machine this is the
   * callback we use.
   */

  static void do_poweroff(struct work_struct *dummy)

  {

  	kernel_power_off();

  }

  static DECLARE_WORK(poweroff_work, do_poweroff);

  static void handle_poweroff(int key)

  {

  	/* run sysrq poweroff on boot cpu */

  	schedule_work_on(cpumask_first(cpu_online_mask), &poweroff_work);

  }
  
  static struct sysrq_key_op	sysrq_poweroff_op = {
  	.handler        = handle_poweroff,
  	.help_msg       = "powerOff",
  	.action_msg     = "Power Off",

  	.enable_mask	= SYSRQ_ENABLE_BOOT,

  };
  
  static int pm_sysrq_init(void)
  {
  	register_sysrq_key('o', &sysrq_poweroff_op);
  	return 0;
  }
  
  subsys_initcall(pm_sysrq_init);