/*
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   *
   * Copyright (C) 1997, 1998, 2001, 03, 05, 06 by Ralf Baechle
   */
  #include <linux/linkage.h>
  #include <linux/init.h>
  #include <linux/ds1286.h>
  #include <linux/module.h>
  #include <linux/interrupt.h>
  #include <linux/kernel.h>
  #include <linux/sched.h>
  #include <linux/notifier.h>
  #include <linux/pm.h>
  #include <linux/timer.h>
  
  #include <asm/io.h>
  #include <asm/irq.h>
  #include <asm/reboot.h>
  #include <asm/sgialib.h>
  #include <asm/sgi/ioc.h>
  #include <asm/sgi/hpc3.h>
  #include <asm/sgi/mc.h>
  #include <asm/sgi/ip22.h>
  
  /*
   * Just powerdown if init hasn't done after POWERDOWN_TIMEOUT seconds.
   * I'm not sure if this feature is a good idea, for now it's here just to
   * make the power button make behave just like under IRIX.
   */
  #define POWERDOWN_TIMEOUT	120
  
  /*
   * Blink frequency during reboot grace period and when panicked.
   */
  #define POWERDOWN_FREQ		(HZ / 4)
  #define PANIC_FREQ		(HZ / 8)
  
  static struct timer_list power_timer, blink_timer, debounce_timer;
  
  #define MACHINE_PANICED		1
  #define MACHINE_SHUTTING_DOWN	2
  
  static int machine_state;
  
  static void __noreturn sgi_machine_power_off(void)
  {
  	unsigned int tmp;
  
  	local_irq_disable();
  
  	/* Disable watchdog */
  	tmp = hpc3c0->rtcregs[RTC_CMD] & 0xff;
  	hpc3c0->rtcregs[RTC_CMD] = tmp | RTC_WAM;
  	hpc3c0->rtcregs[RTC_WSEC] = 0;
  	hpc3c0->rtcregs[RTC_WHSEC] = 0;
  
  	while (1) {
  		sgioc->panel = ~SGIOC_PANEL_POWERON;
  		/* Good bye cruel world ...  */
  
  		/* If we're still running, we probably got sent an alarm
  		   interrupt.  Read the flag to clear it.  */
  		tmp = hpc3c0->rtcregs[RTC_HOURS_ALARM];
  	}
  }
  
  static void __noreturn sgi_machine_restart(char *command)
  {
  	if (machine_state & MACHINE_SHUTTING_DOWN)
  		sgi_machine_power_off();
  	sgimc->cpuctrl0 |= SGIMC_CCTRL0_SYSINIT;
  	while (1);
  }
  
  static void __noreturn sgi_machine_halt(void)
  {
  	if (machine_state & MACHINE_SHUTTING_DOWN)
  		sgi_machine_power_off();
  	ArcEnterInteractiveMode();
  }
  
  static void power_timeout(unsigned long data)
  {
  	sgi_machine_power_off();
  }
  
  static void blink_timeout(unsigned long data)
  {
  	/* XXX fix this for fullhouse  */
  	sgi_ioc_reset ^= (SGIOC_RESET_LC0OFF|SGIOC_RESET_LC1OFF);
  	sgioc->reset = sgi_ioc_reset;
  
  	mod_timer(&blink_timer, jiffies + data);
  }
  
  static void debounce(unsigned long data)
  {
  	del_timer(&debounce_timer);
  	if (sgint->istat1 & SGINT_ISTAT1_PWR) {
  		/* Interrupt still being sent. */
  		debounce_timer.expires = jiffies + (HZ / 20); /* 0.05s	*/
  		add_timer(&debounce_timer);
  
  		sgioc->panel = SGIOC_PANEL_POWERON | SGIOC_PANEL_POWERINTR |
  			       SGIOC_PANEL_VOLDNINTR | SGIOC_PANEL_VOLDNHOLD |
  			       SGIOC_PANEL_VOLUPINTR | SGIOC_PANEL_VOLUPHOLD;
  
  		return;
  	}
  
  	if (machine_state & MACHINE_PANICED)
  		sgimc->cpuctrl0 |= SGIMC_CCTRL0_SYSINIT;
  
  	enable_irq(SGI_PANEL_IRQ);
  }
  
  static inline void power_button(void)
  {
  	if (machine_state & MACHINE_PANICED)
  		return;
  
  	if ((machine_state & MACHINE_SHUTTING_DOWN) ||
  			kill_cad_pid(SIGINT, 1)) {
  		/* No init process or button pressed twice.  */
  		sgi_machine_power_off();
  	}
  
  	machine_state |= MACHINE_SHUTTING_DOWN;
  	blink_timer.data = POWERDOWN_FREQ;
  	blink_timeout(POWERDOWN_FREQ);
  
  	init_timer(&power_timer);
  	power_timer.function = power_timeout;
  	power_timer.expires = jiffies + POWERDOWN_TIMEOUT * HZ;
  	add_timer(&power_timer);
  }
  
  static irqreturn_t panel_int(int irq, void *dev_id)
  {
  	unsigned int buttons;
  
  	buttons = sgioc->panel;
  	sgioc->panel = SGIOC_PANEL_POWERON | SGIOC_PANEL_POWERINTR;
  
  	if (sgint->istat1 & SGINT_ISTAT1_PWR) {
  		/* Wait until interrupt goes away */
  		disable_irq_nosync(SGI_PANEL_IRQ);
  		init_timer(&debounce_timer);
  		debounce_timer.function = debounce;
  		debounce_timer.expires = jiffies + 5;
  		add_timer(&debounce_timer);
  	}
  
  	/* Power button was pressed
  	 * ioc.ps page 22: "The Panel Register is called Power Control by Full
  	 * House. Only lowest 2 bits are used. Guiness uses upper four bits
  	 * for volume control". This is not true, all bits are pulled high
  	 * on fullhouse */
  	if (!(buttons & SGIOC_PANEL_POWERINTR))
  		power_button();
  
  	return IRQ_HANDLED;
  }
  
  static int panic_event(struct notifier_block *this, unsigned long event,
  		      void *ptr)
  {
  	if (machine_state & MACHINE_PANICED)
  		return NOTIFY_DONE;
  	machine_state |= MACHINE_PANICED;
  
  	blink_timer.data = PANIC_FREQ;
  	blink_timeout(PANIC_FREQ);
  
  	return NOTIFY_DONE;
  }
  
  static struct notifier_block panic_block = {
  	.notifier_call	= panic_event,
  };
  
  static int __init reboot_setup(void)
  {
  	int res;
  
  	_machine_restart = sgi_machine_restart;
  	_machine_halt = sgi_machine_halt;
  	pm_power_off = sgi_machine_power_off;
  
  	res = request_irq(SGI_PANEL_IRQ, panel_int, 0, "Front Panel", NULL);
  	if (res) {
  		printk(KERN_ERR "Allocation of front panel IRQ failed
  ");
  		return res;
  	}
  
  	init_timer(&blink_timer);
  	blink_timer.function = blink_timeout;
  	atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
  
  	return 0;
  }
  
  subsys_initcall(reboot_setup);