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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 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/sched.h>
  11 #include <linux/signal.h>
  12 #include <linux/delay.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/pm.h>
  15 #include <linux/syscalls.h>
  16
  17 #include <asm/system.h>
  18 #include <asm/auxio.h>
  19 #include <asm/prom.h>
  20 #include <asm/of_device.h>
  21 #include <asm/io.h>
  22
  23 #include <linux/unistd.h>
  24
  25 /*
  26  * sysctl - toggle power-off restriction for serial console
  27  * systems in machine_power_off()
  28  */
  29 int scons_pwroff = 1;
  30
  31 #ifdef CONFIG_PCI
  32 #include <linux/pci.h>
  33 static void __iomem *power_reg;
  34
  35 static DECLARE_WAIT_QUEUE_HEAD(powerd_wait);
  36 static int button_pressed;
  37
  38 static irqreturn_t power_handler(int irq, void *dev_id)
  39 {
  40         if (button_pressed == 0) {
  41                 button_pressed = 1;
  42                 wake_up(&powerd_wait);
  43         }
  44
  45         /* FIXME: Check registers for status... */
  46         return IRQ_HANDLED;
  47 }
  48 #endif /* CONFIG_PCI */
  49
  50 extern void machine_halt(void);
  51 extern void machine_alt_power_off(void);
  52 static void (*poweroff_method)(void) = machine_alt_power_off;
  53
  54 void machine_power_off(void)
  55 {
  56         if (!serial_console || scons_pwroff) {
  57 #ifdef CONFIG_PCI
  58                 if (power_reg) {
  59                         /* Both register bits seem to have the
  60                          * same effect, so until I figure out
  61                          * what the difference is...
  62                          */
  63                         writel(AUXIO_PCIO_CPWR_OFF | AUXIO_PCIO_SPWR_OFF, power_reg);
  64                 } else
  65 #endif /* CONFIG_PCI */
  66                         if (poweroff_method != NULL) {
  67                                 poweroff_method();
  68                                 /* not reached */
  69                         }
  70         }
  71         machine_halt();
  72 }
  73
  74 void (*pm_power_off)(void) = machine_power_off;
  75 EXPORT_SYMBOL(pm_power_off);
  76
  77 #ifdef CONFIG_PCI
  78 static int powerd(void *__unused)
  79 {
  80         static char *envp[] = { "HOME=/", "TERM=linux", "PATH=/sbin:/usr/sbin:/bin:/usr/bin", NULL };
  81         char *argv[] = { "/sbin/shutdown", "-h", "now", NULL };
  82         DECLARE_WAITQUEUE(wait, current);
  83
  84         daemonize("powerd");
  85
  86         add_wait_queue(&powerd_wait, &wait);
  87 again:
  88         for (;;) {
  89                 set_task_state(current, TASK_INTERRUPTIBLE);
  90                 if (button_pressed)
  91                         break;
  92                 flush_signals(current);
  93                 schedule();
  94         }
  95         __set_current_state(TASK_RUNNING);
  96         remove_wait_queue(&powerd_wait, &wait);
  97
  98         /* Ok, down we go... */
  99         button_pressed = 0;
 100         if (kernel_execve("/sbin/shutdown", argv, envp) < 0) {
 101                 printk("powerd: shutdown execution failed\n");
 102                 add_wait_queue(&powerd_wait, &wait);
 103                 goto again;
 104         }
 105         return 0;
 106 }
 107
 108 static int __init has_button_interrupt(unsigned int irq, struct device_node *dp)
 109 {
 110         if (irq == PCI_IRQ_NONE)
 111                 return 0;
 112         if (!of_find_property(dp, "button", NULL))
 113                 return 0;
 114
 115         return 1;
 116 }
 117
 118 static int __devinit power_probe(struct of_device *op, const struct of_device_id *match)
 119 {
 120         struct resource *res = &op->resource[0];
 121         unsigned int irq= op->irqs[0];
 122
 123         power_reg = of_ioremap(res, 0, 0x4, "power");
 124
 125         printk("%s: Control reg at %lx ... ",
 126                op->node->name, res->start);
 127
 128         poweroff_method = machine_halt;  /* able to use the standard halt */
 129
 130         if (has_button_interrupt(irq, op->node)) {
 131                 if (kernel_thread(powerd, NULL, CLONE_FS) < 0) {
 132                         printk("Failed to start power daemon.\n");
 133                         return 0;
 134                 }
 135                 printk("powerd running.\n");
 136
 137                 if (request_irq(irq,
 138                                 power_handler, 0, "power", NULL) < 0)
 139                         printk("power: Error, cannot register IRQ handler.\n");
 140         } else {
 141                 printk("not using powerd.\n");
 142         }
 143
 144         return 0;
 145 }
 146
 147 static struct of_device_id power_match[] = {
 148         {
 149                 .name = "power",
 150         },
 151         {},
 152 };
 153
 154 static struct of_platform_driver power_driver = {
 155         .name           = "power",
 156         .match_table    = power_match,
 157         .probe          = power_probe,
 158 };
 159
 160 void __init power_init(void)
 161 {
 162         of_register_driver(&power_driver, &of_bus_type);
 163         return;
 164 }
 165 #endif /* CONFIG_PCI */