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