arch/sparc64/kernel/power.c

   1 /* $Id: power.c,v 1.4 1999/08/31 18:22:05 davem Exp $
   2  * power.c: Power management driver.
   3  *
   4  * Copyright (C) 1999 David S. Miller (davem@redhat.com)
   5  */
   6
   7 #include <linux/config.h>
   8 #include <linux/kernel.h>
   9 #include <linux/init.h>
  10 #include <linux/sched.h>
  11 #include <linux/signal.h>
  12 #include <linux/delay.h>
  13
  14 #include <asm/ebus.h>
  15
  16 #define __KERNEL_SYSCALLS__
  17 #include <linux/unistd.h>
  18
  19 #ifdef CONFIG_PCI
  20 static unsigned long power_reg = 0UL;
  21 #define POWER_SYSTEM_OFF (1 << 0)
  22 #define POWER_COURTESY_OFF (1 << 1)
  23
  24 static DECLARE_WAIT_QUEUE_HEAD(powerd_wait);
  25 static int button_pressed = 0;
  26
  27 static void power_handler(int irq, void *dev_id, struct pt_regs *regs)
  28 {
  29         if (button_pressed == 0) {
  30                 wake_up(&powerd_wait);
  31                 button_pressed = 1;
  32         }
  33 }
  34 #endif /* CONFIG_PCI */
  35
  36 extern void machine_halt(void);
  37
  38 void machine_power_off(void)
  39 {
  40 #ifdef CONFIG_PCI
  41         if (power_reg != 0UL) {
  42                 /* Both register bits seem to have the
  43                  * same effect, so until I figure out
  44                  * what the difference is...
  45                  */
  46                 writel(POWER_COURTESY_OFF | POWER_SYSTEM_OFF, power_reg);
  47         }
  48 #endif /* CONFIG_PCI */
  49         machine_halt();
  50 }
  51
  52 #ifdef CONFIG_PCI
  53 static int powerd(void *__unused)
  54 {
  55         static char *envp[] = { "HOME=/", "TERM=linux", "PATH=/sbin:/usr/sbin:/bin:/usr/bin", NULL };
  56         char *argv[] = { "/usr/bin/shutdown", "-h", "now", NULL };
  57
  58         current->session = 1;
  59         current->pgrp = 1;
  60         sprintf(current->comm, "powerd");
  61
  62 again:
  63         while(button_pressed == 0) {
  64                 spin_lock_irq(&current->sigmask_lock);
  65                 flush_signals(current);
  66                 spin_unlock_irq(&current->sigmask_lock);
  67                 interruptible_sleep_on(&powerd_wait);
  68         }
  69
  70         /* Ok, down we go... */
  71         if (execve("/usr/bin/shutdown", argv, envp) < 0) {
  72                 printk("powerd: shutdown execution failed\n");
  73                 button_pressed = 0;
  74                 goto again;
  75         }
  76         return 0;
  77 }
  78
  79 void __init power_init(void)
  80 {
  81         struct linux_ebus *ebus;
  82         struct linux_ebus_device *edev;
  83
  84         for_each_ebus(ebus) {
  85                 for_each_ebusdev(edev, ebus) {
  86                         if (!strcmp(edev->prom_name, "power"))
  87                                 goto found;
  88                 }
  89         }
  90         return;
  91
  92 found:
  93         power_reg = edev->resource[0].start;
  94         printk("power: Control reg at %016lx ... ", power_reg);
  95         if (kernel_thread(powerd, 0, CLONE_FS) < 0) {
  96                 printk("Failed to start power daemon.\n");
  97                 return;
  98         }
  99         printk("powerd running.\n");
 100         if (request_irq(edev->irqs[0],
 101                         power_handler, SA_SHIRQ, "power",
 102                         (void *) power_reg) < 0)
 103                 printk("power: Error, cannot register IRQ handler.\n");
 104 }
 105 #endif /* CONFIG_PCI */