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   1 /* $Id: power.c,v 1.10 2001/12/11 01:57:16 davem Exp $
   2  * power.c: Power management driver.
   3  *
   4  * Copyright (C) 1999 David S. Miller (davem@redhat.com)
   5  */
   6
   7 #define __KERNEL_SYSCALLS__
   8
   9 #include <linux/config.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/sched.h>
  14 #include <linux/signal.h>
  15 #include <linux/delay.h>
  16 #include <linux/interrupt.h>
  17
  18 #include <asm/system.h>
  19 #include <asm/ebus.h>
  20 #include <asm/auxio.h>
  21
  22 #include <linux/unistd.h>
  23
  24 /*
  25  * sysctl - toggle power-off restriction for serial console
  26  * systems in machine_power_off()
  27  */
  28 int scons_pwroff = 1;
  29
  30 #ifdef CONFIG_PCI
  31 static void __iomem *power_reg;
  32
  33 static DECLARE_WAIT_QUEUE_HEAD(powerd_wait);
  34 static int button_pressed;
  35
  36 static irqreturn_t power_handler(int irq, void *dev_id, struct pt_regs *regs)
  37 {
  38         if (button_pressed == 0) {
  39                 button_pressed = 1;
  40                 wake_up(&powerd_wait);
  41         }
  42
  43         /* FIXME: Check registers for status... */
  44         return IRQ_HANDLED;
  45 }
  46 #endif /* CONFIG_PCI */
  47
  48 extern void machine_halt(void);
  49 extern void machine_alt_power_off(void);
  50 static void (*poweroff_method)(void) = machine_alt_power_off;
  51
  52 void machine_power_off(void)
  53 {
  54         if (!serial_console || scons_pwroff) {
  55 #ifdef CONFIG_PCI
  56                 if (power_reg) {
  57                         /* Both register bits seem to have the
  58                          * same effect, so until I figure out
  59                          * what the difference is...
  60                          */
  61                         writel(AUXIO_PCIO_CPWR_OFF | AUXIO_PCIO_SPWR_OFF, power_reg);
  62                 } else
  63 #endif /* CONFIG_PCI */
  64                         if (poweroff_method != NULL) {
  65                                 poweroff_method();
  66                                 /* not reached */
  67                         }
  68         }
  69         machine_halt();
  70 }
  71
  72 EXPORT_SYMBOL(machine_power_off);
  73
  74 #ifdef CONFIG_PCI
  75 static int powerd(void *__unused)
  76 {
  77         static char *envp[] = { "HOME=/", "TERM=linux", "PATH=/sbin:/usr/sbin:/bin:/usr/bin", NULL };
  78         char *argv[] = { "/sbin/shutdown", "-h", "now", NULL };
  79         DECLARE_WAITQUEUE(wait, current);
  80
  81         daemonize("powerd");
  82
  83         add_wait_queue(&powerd_wait, &wait);
  84 again:
  85         for (;;) {
  86                 set_task_state(current, TASK_INTERRUPTIBLE);
  87                 if (button_pressed)
  88                         break;
  89                 flush_signals(current);
  90                 schedule();
  91         }
  92         __set_current_state(TASK_RUNNING);
  93         remove_wait_queue(&powerd_wait, &wait);
  94
  95         /* Ok, down we go... */
  96         button_pressed = 0;
  97         if (execve("/sbin/shutdown", argv, envp) < 0) {
  98                 printk("powerd: shutdown execution failed\n");
  99                 add_wait_queue(&powerd_wait, &wait);
 100                 goto again;
 101         }
 102         return 0;
 103 }
 104
 105 static int __init has_button_interrupt(struct linux_ebus_device *edev)
 106 {
 107         if (edev->irqs[0] == PCI_IRQ_NONE)
 108                 return 0;
 109         if (!prom_node_has_property(edev->prom_node, "button"))
 110                 return 0;
 111
 112         return 1;
 113 }
 114
 115 void __init power_init(void)
 116 {
 117         struct linux_ebus *ebus;
 118         struct linux_ebus_device *edev;
 119         static int invoked;
 120
 121         if (invoked)
 122                 return;
 123         invoked = 1;
 124
 125         for_each_ebus(ebus) {
 126                 for_each_ebusdev(edev, ebus) {
 127                         if (!strcmp(edev->prom_name, "power"))
 128                                 goto found;
 129                 }
 130         }
 131         return;
 132
 133 found:
 134         power_reg = ioremap(edev->resource[0].start, 0x4);
 135         printk("power: Control reg at %p ... ", power_reg);
 136         poweroff_method = machine_halt;  /* able to use the standard halt */
 137         if (has_button_interrupt(edev)) {
 138                 if (kernel_thread(powerd, NULL, CLONE_FS) < 0) {
 139                         printk("Failed to start power daemon.\n");
 140                         return;
 141                 }
 142                 printk("powerd running.\n");
 143
 144                 if (request_irq(edev->irqs[0],
 145                                 power_handler, SA_SHIRQ, "power", NULL) < 0)
 146                         printk("power: Error, cannot register IRQ handler.\n");
 147         } else {
 148                 printk("not using powerd.\n");
 149         }
 150 }
 151 #endif /* CONFIG_PCI */