/* $Id: power.c,v 1.4 1999/08/31 18:22:05 davem Exp $
 * power.c: Power management driver.
 *
 * Copyright (C) 1999 David S. Miller (davem@redhat.com)
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/delay.h>

#include <asm/ebus.h>

#define __KERNEL_SYSCALLS__
#include <linux/unistd.h>

#ifdef CONFIG_PCI
static unsigned long power_reg = 0UL;
#define POWER_SYSTEM_OFF (1 << 0)
#define POWER_COURTESY_OFF (1 << 1)

static DECLARE_WAIT_QUEUE_HEAD(powerd_wait);
static int button_pressed = 0;

static void power_handler(int irq, void *dev_id, struct pt_regs *regs)
{
	if (button_pressed == 0) {
		wake_up(&powerd_wait);
		button_pressed = 1;
	}
}
#endif /* CONFIG_PCI */

extern void machine_halt(void);

void machine_power_off(void)
{
#ifdef CONFIG_PCI
	if (power_reg != 0UL) {
		/* Both register bits seem to have the
		 * same effect, so until I figure out
		 * what the difference is...
		 */
		writel(POWER_COURTESY_OFF | POWER_SYSTEM_OFF, power_reg);
	}
#endif /* CONFIG_PCI */
	machine_halt();
}

#ifdef CONFIG_PCI
static int powerd(void *__unused)
{
	static char *envp[] = { "HOME=/", "TERM=linux", "PATH=/sbin:/usr/sbin:/bin:/usr/bin", NULL };
	char *argv[] = { "/usr/bin/shutdown", "-h", "now", NULL };

	current->session = 1;
	current->pgrp = 1;
	sprintf(current->comm, "powerd");

again:
	while(button_pressed == 0) {
		spin_lock_irq(&current->sigmask_lock);
		flush_signals(current);
		spin_unlock_irq(&current->sigmask_lock);
		interruptible_sleep_on(&powerd_wait);
	}

	/* Ok, down we go... */
	if (execve("/usr/bin/shutdown", argv, envp) < 0) {
		printk("powerd: shutdown execution failed\n");
		button_pressed = 0;
		goto again;
	}
	return 0;
}

void __init power_init(void)
{
	struct linux_ebus *ebus;
	struct linux_ebus_device *edev;

	for_each_ebus(ebus) {
		for_each_ebusdev(edev, ebus) {
			if (!strcmp(edev->prom_name, "power"))
				goto found;
		}
	}
	return;

found:
	power_reg = edev->resource[0].start;
	printk("power: Control reg at %016lx ... ", power_reg);
	if (kernel_thread(powerd, 0, CLONE_FS) < 0) {
		printk("Failed to start power daemon.\n");
		return;
	}
	printk("powerd running.\n");
	if (request_irq(edev->irqs[0],
			power_handler, SA_SHIRQ, "power",
			(void *) power_reg) < 0)
		printk("power: Error, cannot register IRQ handler.\n");
}
#endif /* CONFIG_PCI */