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/kmod.h>
  16 #include <linux/console.h>
  17 #include <linux/cpu.h>
  18 #include <linux/syscalls.h>
  19 #include <linux/gfp.h>
  20 #include <linux/io.h>
  21 #include <linux/kernel.h>
  22 #include <linux/list.h>
  23 #include <linux/mm.h>
  24 #include <linux/slab.h>
  25 #include <linux/export.h>
  26 #include <linux/suspend.h>
  27 #include <linux/syscore_ops.h>
  28 #include <trace/events/power.h>
  29
  30 #include "power.h"
  31
  32 const char *const pm_states[PM_SUSPEND_MAX] = {
  33         [PM_SUSPEND_STANDBY]    = "standby",
  34         [PM_SUSPEND_MEM]        = "mem",
  35 };
  36
  37 static const struct platform_suspend_ops *suspend_ops;
  38
  39 /**
  40  *      suspend_set_ops - Set the global suspend method table.
  41  *      @ops:   Pointer to ops structure.
  42  */
  43 void suspend_set_ops(const struct platform_suspend_ops *ops)
  44 {
  45         mutex_lock(&pm_mutex);
  46         suspend_ops = ops;
  47         mutex_unlock(&pm_mutex);
  48 }
  49 EXPORT_SYMBOL_GPL(suspend_set_ops);
  50
  51 bool valid_state(suspend_state_t state)
  52 {
  53         /*
  54          * All states need lowlevel support and need to be valid to the lowlevel
  55          * implementation, no valid callback implies that none are valid.
  56          */
  57         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  58 }
  59
  60 /**
  61  * suspend_valid_only_mem - generic memory-only valid callback
  62  *
  63  * Platform drivers that implement mem suspend only and only need
  64  * to check for that in their .valid callback can use this instead
  65  * of rolling their own .valid callback.
  66  */
  67 int suspend_valid_only_mem(suspend_state_t state)
  68 {
  69         return state == PM_SUSPEND_MEM;
  70 }
  71 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
  72
  73 static int suspend_test(int level)
  74 {
  75 #ifdef CONFIG_PM_DEBUG
  76         if (pm_test_level == level) {
  77                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  78                 mdelay(5000);
  79                 return 1;
  80         }
  81 #endif /* !CONFIG_PM_DEBUG */
  82         return 0;
  83 }
  84
  85 /**
  86  *      suspend_prepare - Do prep work before entering low-power state.
  87  *
  88  *      This is common code that is called for each state that we're entering.
  89  *      Run suspend notifiers, allocate a console and stop all processes.
  90  */
  91 static int suspend_prepare(void)
  92 {
  93         int error;
  94
  95         if (!suspend_ops || !suspend_ops->enter)
  96                 return -EPERM;
  97
  98         pm_prepare_console();
  99
 100         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 101         if (error)
 102                 goto Finish;
 103
 104         error = usermodehelper_disable();
 105         if (error)
 106                 goto Finish;
 107
 108         error = suspend_freeze_processes();
 109         if (!error)
 110                 return 0;
 111
 112         suspend_thaw_processes();
 113         usermodehelper_enable();
 114  Finish:
 115         pm_notifier_call_chain(PM_POST_SUSPEND);
 116         pm_restore_console();
 117         return error;
 118 }
 119
 120 /* default implementation */
 121 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 122 {
 123         local_irq_disable();
 124 }
 125
 126 /* default implementation */
 127 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 128 {
 129         local_irq_enable();
 130 }
 131
 132 /**
 133  * suspend_enter - enter the desired system sleep state.
 134  * @state: State to enter
 135  * @wakeup: Returns information that suspend should not be entered again.
 136  *
 137  * This function should be called after devices have been suspended.
 138  */
 139 static int suspend_enter(suspend_state_t state, bool *wakeup)
 140 {
 141         int error;
 142
 143         if (suspend_ops->prepare) {
 144                 error = suspend_ops->prepare();
 145                 if (error)
 146                         goto Platform_finish;
 147         }
 148
 149         error = dpm_suspend_noirq(PMSG_SUSPEND);
 150         if (error) {
 151                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 152                 goto Platform_finish;
 153         }
 154
 155         if (suspend_ops->prepare_late) {
 156                 error = suspend_ops->prepare_late();
 157                 if (error)
 158                         goto Platform_wake;
 159         }
 160
 161         if (suspend_test(TEST_PLATFORM))
 162                 goto Platform_wake;
 163
 164         error = disable_nonboot_cpus();
 165         if (error || suspend_test(TEST_CPUS))
 166                 goto Enable_cpus;
 167
 168         arch_suspend_disable_irqs();
 169         BUG_ON(!irqs_disabled());
 170
 171         error = syscore_suspend();
 172         if (!error) {
 173                 *wakeup = pm_wakeup_pending();
 174                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 175                         error = suspend_ops->enter(state);
 176                         events_check_enabled = false;
 177                 }
 178                 syscore_resume();
 179         }
 180
 181         arch_suspend_enable_irqs();
 182         BUG_ON(irqs_disabled());
 183
 184  Enable_cpus:
 185         enable_nonboot_cpus();
 186
 187  Platform_wake:
 188         if (suspend_ops->wake)
 189                 suspend_ops->wake();
 190
 191         dpm_resume_noirq(PMSG_RESUME);
 192
 193  Platform_finish:
 194         if (suspend_ops->finish)
 195                 suspend_ops->finish();
 196
 197         return error;
 198 }
 199
 200 /**
 201  *      suspend_devices_and_enter - suspend devices and enter the desired system
 202  *                                  sleep state.
 203  *      @state:           state to enter
 204  */
 205 int suspend_devices_and_enter(suspend_state_t state)
 206 {
 207         int error;
 208         bool wakeup = false;
 209
 210         if (!suspend_ops)
 211                 return -ENOSYS;
 212
 213         trace_machine_suspend(state);
 214         if (suspend_ops->begin) {
 215                 error = suspend_ops->begin(state);
 216                 if (error)
 217                         goto Close;
 218         }
 219         suspend_console();
 220         suspend_test_start();
 221         error = dpm_suspend_start(PMSG_SUSPEND);
 222         if (error) {
 223                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 224                 goto Recover_platform;
 225         }
 226         suspend_test_finish("suspend devices");
 227         if (suspend_test(TEST_DEVICES))
 228                 goto Recover_platform;
 229
 230         do {
 231                 error = suspend_enter(state, &wakeup);
 232         } while (!error && !wakeup
 233                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 234
 235  Resume_devices:
 236         suspend_test_start();
 237         dpm_resume_end(PMSG_RESUME);
 238         suspend_test_finish("resume devices");
 239         resume_console();
 240  Close:
 241         if (suspend_ops->end)
 242                 suspend_ops->end();
 243         trace_machine_suspend(PWR_EVENT_EXIT);
 244         return error;
 245
 246  Recover_platform:
 247         if (suspend_ops->recover)
 248                 suspend_ops->recover();
 249         goto Resume_devices;
 250 }
 251
 252 /**
 253  *      suspend_finish - Do final work before exiting suspend sequence.
 254  *
 255  *      Call platform code to clean up, restart processes, and free the
 256  *      console that we've allocated. This is not called for suspend-to-disk.
 257  */
 258 static void suspend_finish(void)
 259 {
 260         suspend_thaw_processes();
 261         usermodehelper_enable();
 262         pm_notifier_call_chain(PM_POST_SUSPEND);
 263         pm_restore_console();
 264 }
 265
 266 /**
 267  *      enter_state - Do common work of entering low-power state.
 268  *      @state:         pm_state structure for state we're entering.
 269  *
 270  *      Make sure we're the only ones trying to enter a sleep state. Fail
 271  *      if someone has beat us to it, since we don't want anything weird to
 272  *      happen when we wake up.
 273  *      Then, do the setup for suspend, enter the state, and cleaup (after
 274  *      we've woken up).
 275  */
 276 int enter_state(suspend_state_t state)
 277 {
 278         int error;
 279
 280         if (!valid_state(state))
 281                 return -ENODEV;
 282
 283         if (!mutex_trylock(&pm_mutex))
 284                 return -EBUSY;
 285
 286         printk(KERN_INFO "PM: Syncing filesystems ... ");
 287         sys_sync();
 288         printk("done.\n");
 289
 290         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 291         error = suspend_prepare();
 292         if (error)
 293                 goto Unlock;
 294
 295         if (suspend_test(TEST_FREEZER))
 296                 goto Finish;
 297
 298         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 299         pm_restrict_gfp_mask();
 300         error = suspend_devices_and_enter(state);
 301         pm_restore_gfp_mask();
 302
 303  Finish:
 304         pr_debug("PM: Finishing wakeup.\n");
 305         suspend_finish();
 306  Unlock:
 307         mutex_unlock(&pm_mutex);
 308         return error;
 309 }
 310
 311 /**
 312  *      pm_suspend - Externally visible function for suspending system.
 313  *      @state:         Enumerated value of state to enter.
 314  *
 315  *      Determine whether or not value is within range, get state
 316  *      structure, and enter (above).
 317  */
 318 int pm_suspend(suspend_state_t state)
 319 {
 320         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 321                 return enter_state(state);
 322         return -EINVAL;
 323 }
 324 EXPORT_SYMBOL(pm_suspend);