kernel/power/suspend.c

   1 /*
   2  * kernel/power/suspend.c - Suspend to RAM and standby functionality.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   7  *
   8  * This file is released under the GPLv2.
   9  */
  10
  11 #include <linux/string.h>
  12 #include <linux/delay.h>
  13 #include <linux/errno.h>
  14 #include <linux/init.h>
  15 #include <linux/console.h>
  16 #include <linux/cpu.h>
  17 #include <linux/syscalls.h>
  18 #include <linux/gfp.h>
  19
  20 #include "power.h"
  21
  22 const char *const pm_states[PM_SUSPEND_MAX] = {
  23         [PM_SUSPEND_STANDBY]    = "standby",
  24         [PM_SUSPEND_MEM]        = "mem",
  25 };
  26
  27 static struct platform_suspend_ops *suspend_ops;
  28
  29 /**
  30  *      suspend_set_ops - Set the global suspend method table.
  31  *      @ops:   Pointer to ops structure.
  32  */
  33 void suspend_set_ops(struct platform_suspend_ops *ops)
  34 {
  35         mutex_lock(&pm_mutex);
  36         suspend_ops = ops;
  37         mutex_unlock(&pm_mutex);
  38 }
  39
  40 bool valid_state(suspend_state_t state)
  41 {
  42         /*
  43          * All states need lowlevel support and need to be valid to the lowlevel
  44          * implementation, no valid callback implies that none are valid.
  45          */
  46         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  47 }
  48
  49 /**
  50  * suspend_valid_only_mem - generic memory-only valid callback
  51  *
  52  * Platform drivers that implement mem suspend only and only need
  53  * to check for that in their .valid callback can use this instead
  54  * of rolling their own .valid callback.
  55  */
  56 int suspend_valid_only_mem(suspend_state_t state)
  57 {
  58         return state == PM_SUSPEND_MEM;
  59 }
  60
  61 static int suspend_test(int level)
  62 {
  63 #ifdef CONFIG_PM_DEBUG
  64         if (pm_test_level == level) {
  65                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  66                 mdelay(5000);
  67                 return 1;
  68         }
  69 #endif /* !CONFIG_PM_DEBUG */
  70         return 0;
  71 }
  72
  73 /**
  74  *      suspend_prepare - Do prep work before entering low-power state.
  75  *
  76  *      This is common code that is called for each state that we're entering.
  77  *      Run suspend notifiers, allocate a console and stop all processes.
  78  */
  79 static int suspend_prepare(void)
  80 {
  81         int error;
  82
  83         if (!suspend_ops || !suspend_ops->enter)
  84                 return -EPERM;
  85
  86         pm_prepare_console();
  87
  88         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
  89         if (error)
  90                 goto Finish;
  91
  92         error = usermodehelper_disable();
  93         if (error)
  94                 goto Finish;
  95
  96         error = suspend_freeze_processes();
  97         if (!error)
  98                 return 0;
  99
 100         suspend_thaw_processes();
 101         usermodehelper_enable();
 102  Finish:
 103         pm_notifier_call_chain(PM_POST_SUSPEND);
 104         pm_restore_console();
 105         return error;
 106 }
 107
 108 /* default implementation */
 109 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 110 {
 111         local_irq_disable();
 112 }
 113
 114 /* default implementation */
 115 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 116 {
 117         local_irq_enable();
 118 }
 119
 120 /**
 121  *      suspend_enter - enter the desired system sleep state.
 122  *      @state:         state to enter
 123  *
 124  *      This function should be called after devices have been suspended.
 125  */
 126 static int suspend_enter(suspend_state_t state)
 127 {
 128         int error;
 129
 130         if (suspend_ops->prepare) {
 131                 error = suspend_ops->prepare();
 132                 if (error)
 133                         return error;
 134         }
 135
 136         error = dpm_suspend_noirq(PMSG_SUSPEND);
 137         if (error) {
 138                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 139                 goto Platfrom_finish;
 140         }
 141
 142         if (suspend_ops->prepare_late) {
 143                 error = suspend_ops->prepare_late();
 144                 if (error)
 145                         goto Power_up_devices;
 146         }
 147
 148         if (suspend_test(TEST_PLATFORM))
 149                 goto Platform_wake;
 150
 151         error = disable_nonboot_cpus();
 152         if (error || suspend_test(TEST_CPUS))
 153                 goto Enable_cpus;
 154
 155         arch_suspend_disable_irqs();
 156         BUG_ON(!irqs_disabled());
 157
 158         error = sysdev_suspend(PMSG_SUSPEND);
 159         if (!error) {
 160                 if (!suspend_test(TEST_CORE))
 161                         error = suspend_ops->enter(state);
 162                 sysdev_resume();
 163         }
 164
 165         arch_suspend_enable_irqs();
 166         BUG_ON(irqs_disabled());
 167
 168  Enable_cpus:
 169         enable_nonboot_cpus();
 170
 171  Platform_wake:
 172         if (suspend_ops->wake)
 173                 suspend_ops->wake();
 174
 175  Power_up_devices:
 176         dpm_resume_noirq(PMSG_RESUME);
 177
 178  Platfrom_finish:
 179         if (suspend_ops->finish)
 180                 suspend_ops->finish();
 181
 182         return error;
 183 }
 184
 185 /**
 186  *      suspend_devices_and_enter - suspend devices and enter the desired system
 187  *                                  sleep state.
 188  *      @state:           state to enter
 189  */
 190 int suspend_devices_and_enter(suspend_state_t state)
 191 {
 192         int error;
 193         gfp_t saved_mask;
 194
 195         if (!suspend_ops)
 196                 return -ENOSYS;
 197
 198         if (suspend_ops->begin) {
 199                 error = suspend_ops->begin(state);
 200                 if (error)
 201                         goto Close;
 202         }
 203         suspend_console();
 204         saved_mask = clear_gfp_allowed_mask(GFP_IOFS);
 205         suspend_test_start();
 206         error = dpm_suspend_start(PMSG_SUSPEND);
 207         if (error) {
 208                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 209                 goto Recover_platform;
 210         }
 211         suspend_test_finish("suspend devices");
 212         if (suspend_test(TEST_DEVICES))
 213                 goto Recover_platform;
 214
 215         suspend_enter(state);
 216
 217  Resume_devices:
 218         suspend_test_start();
 219         dpm_resume_end(PMSG_RESUME);
 220         suspend_test_finish("resume devices");
 221         set_gfp_allowed_mask(saved_mask);
 222         resume_console();
 223  Close:
 224         if (suspend_ops->end)
 225                 suspend_ops->end();
 226         return error;
 227
 228  Recover_platform:
 229         if (suspend_ops->recover)
 230                 suspend_ops->recover();
 231         goto Resume_devices;
 232 }
 233
 234 /**
 235  *      suspend_finish - Do final work before exiting suspend sequence.
 236  *
 237  *      Call platform code to clean up, restart processes, and free the
 238  *      console that we've allocated. This is not called for suspend-to-disk.
 239  */
 240 static void suspend_finish(void)
 241 {
 242         suspend_thaw_processes();
 243         usermodehelper_enable();
 244         pm_notifier_call_chain(PM_POST_SUSPEND);
 245         pm_restore_console();
 246 }
 247
 248 /**
 249  *      enter_state - Do common work of entering low-power state.
 250  *      @state:         pm_state structure for state we're entering.
 251  *
 252  *      Make sure we're the only ones trying to enter a sleep state. Fail
 253  *      if someone has beat us to it, since we don't want anything weird to
 254  *      happen when we wake up.
 255  *      Then, do the setup for suspend, enter the state, and cleaup (after
 256  *      we've woken up).
 257  */
 258 int enter_state(suspend_state_t state)
 259 {
 260         int error;
 261
 262         if (!valid_state(state))
 263                 return -ENODEV;
 264
 265         if (!mutex_trylock(&pm_mutex))
 266                 return -EBUSY;
 267
 268         printk(KERN_INFO "PM: Syncing filesystems ... ");
 269         sys_sync();
 270         printk("done.\n");
 271
 272         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 273         error = suspend_prepare();
 274         if (error)
 275                 goto Unlock;
 276
 277         if (suspend_test(TEST_FREEZER))
 278                 goto Finish;
 279
 280         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 281         error = suspend_devices_and_enter(state);
 282
 283  Finish:
 284         pr_debug("PM: Finishing wakeup.\n");
 285         suspend_finish();
 286  Unlock:
 287         mutex_unlock(&pm_mutex);
 288         return error;
 289 }
 290
 291 /**
 292  *      pm_suspend - Externally visible function for suspending system.
 293  *      @state:         Enumerated value of state to enter.
 294  *
 295  *      Determine whether or not value is within range, get state
 296  *      structure, and enter (above).
 297  */
 298 int pm_suspend(suspend_state_t state)
 299 {
 300         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 301                 return enter_state(state);
 302         return -EINVAL;
 303 }
 304 EXPORT_SYMBOL(pm_suspend);