err.no Git - linux-2.6/blob - drivers/base/power/suspend.c

   1 /*
   2  * suspend.c - Functions for putting devices to sleep.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Labs
   6  *
   7  * This file is released under the GPLv2
   8  *
   9  */
  10
  11 #include <linux/device.h>
  12 #include <linux/kallsyms.h>
  13 #include <linux/pm.h>
  14 #include "../base.h"
  15 #include "power.h"
  16
  17 /*
  18  * The entries in the dpm_active list are in a depth first order, simply
  19  * because children are guaranteed to be discovered after parents, and
  20  * are inserted at the back of the list on discovery.
  21  *
  22  * All list on the suspend path are done in reverse order, so we operate
  23  * on the leaves of the device tree (or forests, depending on how you want
  24  * to look at it ;) first. As nodes are removed from the back of the list,
  25  * they are inserted into the front of their destintation lists.
  26  *
  27  * Things are the reverse on the resume path - iterations are done in
  28  * forward order, and nodes are inserted at the back of their destination
  29  * lists. This way, the ancestors will be accessed before their descendents.
  30  */
  31
  32 static inline char *suspend_verb(u32 event)
  33 {
  34         switch (event) {
  35         case PM_EVENT_SUSPEND:  return "suspend";
  36         case PM_EVENT_FREEZE:   return "freeze";
  37         case PM_EVENT_PRETHAW:  return "prethaw";
  38         default:                return "(unknown suspend event)";
  39         }
  40 }
  41
  42
  43 /**
  44  *      suspend_device - Save state of one device.
  45  *      @dev:   Device.
  46  *      @state: Power state device is entering.
  47  */
  48
  49 int suspend_device(struct device * dev, pm_message_t state)
  50 {
  51         int error = 0;
  52
  53         down(&dev->sem);
  54         if (dev->power.power_state.event) {
  55                 dev_dbg(dev, "PM: suspend %d-->%d\n",
  56                         dev->power.power_state.event, state.event);
  57         }
  58         if (dev->parent && dev->parent->power.power_state.event) {
  59                 dev_err(dev,
  60                         "PM: suspend %d->%d, parent %s already %d\n",
  61                         dev->power.power_state.event, state.event,
  62                         dev->parent->bus_id,
  63                         dev->parent->power.power_state.event);
  64         }
  65
  66         dev->power.prev_state = dev->power.power_state;
  67
  68         if (dev->class && dev->class->suspend && !dev->power.power_state.event) {
  69                 dev_dbg(dev, "class %s%s\n",
  70                         suspend_verb(state.event),
  71                         ((state.event == PM_EVENT_SUSPEND)
  72                                         && device_may_wakeup(dev))
  73                                 ? ", may wakeup"
  74                                 : ""
  75                         );
  76                 error = dev->class->suspend(dev, state);
  77                 suspend_report_result(dev->class->suspend, error);
  78         }
  79
  80         if (!error && dev->type && dev->type->suspend && !dev->power.power_state.event) {
  81                 dev_dbg(dev, "%s%s\n",
  82                         suspend_verb(state.event),
  83                         ((state.event == PM_EVENT_SUSPEND)
  84                                         && device_may_wakeup(dev))
  85                                 ? ", may wakeup"
  86                                 : ""
  87                         );
  88                 error = dev->type->suspend(dev, state);
  89                 suspend_report_result(dev->type->suspend, error);
  90         }
  91
  92         if (!error && dev->bus && dev->bus->suspend && !dev->power.power_state.event) {
  93                 dev_dbg(dev, "%s%s\n",
  94                         suspend_verb(state.event),
  95                         ((state.event == PM_EVENT_SUSPEND)
  96                                         && device_may_wakeup(dev))
  97                                 ? ", may wakeup"
  98                                 : ""
  99                         );
 100                 error = dev->bus->suspend(dev, state);
 101                 suspend_report_result(dev->bus->suspend, error);
 102         }
 103         up(&dev->sem);
 104         return error;
 105 }
 106
 107
 108 /*
 109  * This is called with interrupts off, only a single CPU
 110  * running. We can't acquire a mutex or semaphore (and we don't
 111  * need the protection)
 112  */
 113 static int suspend_device_late(struct device *dev, pm_message_t state)
 114 {
 115         int error = 0;
 116
 117         if (dev->bus && dev->bus->suspend_late && !dev->power.power_state.event) {
 118                 dev_dbg(dev, "LATE %s%s\n",
 119                         suspend_verb(state.event),
 120                         ((state.event == PM_EVENT_SUSPEND)
 121                                         && device_may_wakeup(dev))
 122                                 ? ", may wakeup"
 123                                 : ""
 124                         );
 125                 error = dev->bus->suspend_late(dev, state);
 126                 suspend_report_result(dev->bus->suspend_late, error);
 127         }
 128         return error;
 129 }
 130
 131 /**
 132  *      device_suspend - Save state and stop all devices in system.
 133  *      @state:         Power state to put each device in.
 134  *
 135  *      Walk the dpm_active list, call ->suspend() for each device, and move
 136  *      it to the dpm_off list.
 137  *
 138  *      (For historical reasons, if it returns -EAGAIN, that used to mean
 139  *      that the device would be called again with interrupts disabled.
 140  *      These days, we use the "suspend_late()" callback for that, so we
 141  *      print a warning and consider it an error).
 142  *
 143  *      If we get a different error, try and back out.
 144  *
 145  *      If we hit a failure with any of the devices, call device_resume()
 146  *      above to bring the suspended devices back to life.
 147  *
 148  */
 149
 150 int device_suspend(pm_message_t state)
 151 {
 152         int error = 0;
 153
 154         might_sleep();
 155         mutex_lock(&dpm_mtx);
 156         mutex_lock(&dpm_list_mtx);
 157         while (!list_empty(&dpm_active) && error == 0) {
 158                 struct list_head * entry = dpm_active.prev;
 159                 struct device * dev = to_device(entry);
 160
 161                 get_device(dev);
 162                 mutex_unlock(&dpm_list_mtx);
 163
 164                 error = suspend_device(dev, state);
 165
 166                 mutex_lock(&dpm_list_mtx);
 167
 168                 /* Check if the device got removed */
 169                 if (!list_empty(&dev->power.entry)) {
 170                         /* Move it to the dpm_off list */
 171                         if (!error)
 172                                 list_move(&dev->power.entry, &dpm_off);
 173                 }
 174                 if (error)
 175                         printk(KERN_ERR "Could not suspend device %s: "
 176                                 "error %d%s\n",
 177                                 kobject_name(&dev->kobj), error,
 178                                 error == -EAGAIN ? " (please convert to suspend_late)" : "");
 179                 put_device(dev);
 180         }
 181         mutex_unlock(&dpm_list_mtx);
 182         if (error)
 183                 dpm_resume();
 184
 185         mutex_unlock(&dpm_mtx);
 186         return error;
 187 }
 188
 189 EXPORT_SYMBOL_GPL(device_suspend);
 190
 191 /**
 192  *      device_power_down - Shut down special devices.
 193  *      @state:         Power state to enter.
 194  *
 195  *      Walk the dpm_off_irq list, calling ->power_down() for each device that
 196  *      couldn't power down the device with interrupts enabled. When we're
 197  *      done, power down system devices.
 198  */
 199
 200 int device_power_down(pm_message_t state)
 201 {
 202         int error = 0;
 203         struct device * dev;
 204
 205         while (!list_empty(&dpm_off)) {
 206                 struct list_head * entry = dpm_off.prev;
 207
 208                 dev = to_device(entry);
 209                 error = suspend_device_late(dev, state);
 210                 if (error)
 211                         goto Error;
 212                 list_move(&dev->power.entry, &dpm_off_irq);
 213         }
 214
 215         error = sysdev_suspend(state);
 216  Done:
 217         return error;
 218  Error:
 219         printk(KERN_ERR "Could not power down device %s: "
 220                 "error %d\n", kobject_name(&dev->kobj), error);
 221         dpm_power_up();
 222         goto Done;
 223 }
 224
 225 EXPORT_SYMBOL_GPL(device_power_down);
 226
 227 void __suspend_report_result(const char *function, void *fn, int ret)
 228 {
 229         if (ret) {
 230                 printk(KERN_ERR "%s(): ", function);
 231                 print_fn_descriptor_symbol("%s() returns ", (unsigned long)fn);
 232                 printk("%d\n", ret);
 233         }
 234 }
 235 EXPORT_SYMBOL_GPL(__suspend_report_result);