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/export.h>
  25 #include <linux/suspend.h>
  26 #include <linux/syscore_ops.h>
  27 #include <trace/events/power.h>
  28
  29 #include "power.h"
  30
  31 const char *const pm_states[PM_SUSPEND_MAX] = {
  32         [PM_SUSPEND_STANDBY]    = "standby",
  33         [PM_SUSPEND_MEM]        = "mem",
  34 };
  35
  36 static const struct platform_suspend_ops *suspend_ops;
  37
  38 /**
  39  *      suspend_set_ops - Set the global suspend method table.
  40  *      @ops:   Pointer to ops structure.
  41  */
  42 void suspend_set_ops(const struct platform_suspend_ops *ops)
  43 {
  44         lock_system_sleep();
  45         suspend_ops = ops;
  46         unlock_system_sleep();
  47 }
  48 EXPORT_SYMBOL_GPL(suspend_set_ops);
  49
  50 bool valid_state(suspend_state_t state)
  51 {
  52         /*
  53          * All states need lowlevel support and need to be valid to the lowlevel
  54          * implementation, no valid callback implies that none are valid.
  55          */
  56         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  57 }
  58
  59 /**
  60  * suspend_valid_only_mem - generic memory-only valid callback
  61  *
  62  * Platform drivers that implement mem suspend only and only need
  63  * to check for that in their .valid callback can use this instead
  64  * of rolling their own .valid callback.
  65  */
  66 int suspend_valid_only_mem(suspend_state_t state)
  67 {
  68         return state == PM_SUSPEND_MEM;
  69 }
  70 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
  71
  72 static int suspend_test(int level)
  73 {
  74 #ifdef CONFIG_PM_DEBUG
  75         if (pm_test_level == level) {
  76                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  77                 mdelay(5000);
  78                 return 1;
  79         }
  80 #endif /* !CONFIG_PM_DEBUG */
  81         return 0;
  82 }
  83
  84 /**
  85  *      suspend_prepare - Do prep work before entering low-power state.
  86  *
  87  *      This is common code that is called for each state that we're entering.
  88  *      Run suspend notifiers, allocate a console and stop all processes.
  89  */
  90 static int suspend_prepare(void)
  91 {
  92         int error;
  93
  94         if (!suspend_ops || !suspend_ops->enter)
  95                 return -EPERM;
  96
  97         pm_prepare_console();
  98
  99         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 100         if (error)
 101                 goto Finish;
 102
 103         error = suspend_freeze_processes();
 104         if (!error)
 105                 return 0;
 106
 107         suspend_stats.failed_freeze++;
 108         dpm_save_failed_step(SUSPEND_FREEZE);
 109  Finish:
 110         pm_notifier_call_chain(PM_POST_SUSPEND);
 111         pm_restore_console();
 112         return error;
 113 }
 114
 115 /* default implementation */
 116 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 117 {
 118         local_irq_disable();
 119 }
 120
 121 /* default implementation */
 122 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 123 {
 124         local_irq_enable();
 125 }
 126
 127 /**
 128  * suspend_enter - enter the desired system sleep state.
 129  * @state: State to enter
 130  * @wakeup: Returns information that suspend should not be entered again.
 131  *
 132  * This function should be called after devices have been suspended.
 133  */
 134 static int suspend_enter(suspend_state_t state, bool *wakeup)
 135 {
 136         int error;
 137
 138         if (suspend_ops->prepare) {
 139                 error = suspend_ops->prepare();
 140                 if (error)
 141                         goto Platform_finish;
 142         }
 143
 144         error = dpm_suspend_noirq(PMSG_SUSPEND);
 145         if (error) {
 146                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 147                 goto Platform_finish;
 148         }
 149
 150         if (suspend_ops->prepare_late) {
 151                 error = suspend_ops->prepare_late();
 152                 if (error)
 153                         goto Platform_wake;
 154         }
 155
 156         if (suspend_test(TEST_PLATFORM))
 157                 goto Platform_wake;
 158
 159         error = disable_nonboot_cpus();
 160         if (error || suspend_test(TEST_CPUS))
 161                 goto Enable_cpus;
 162
 163         arch_suspend_disable_irqs();
 164         BUG_ON(!irqs_disabled());
 165
 166         error = syscore_suspend();
 167         if (!error) {
 168                 *wakeup = pm_wakeup_pending();
 169                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 170                         error = suspend_ops->enter(state);
 171                         events_check_enabled = false;
 172                 }
 173                 syscore_resume();
 174         }
 175
 176         arch_suspend_enable_irqs();
 177         BUG_ON(irqs_disabled());
 178
 179  Enable_cpus:
 180         enable_nonboot_cpus();
 181
 182  Platform_wake:
 183         if (suspend_ops->wake)
 184                 suspend_ops->wake();
 185
 186         dpm_resume_noirq(PMSG_RESUME);
 187
 188  Platform_finish:
 189         if (suspend_ops->finish)
 190                 suspend_ops->finish();
 191
 192         return error;
 193 }
 194
 195 /**
 196  *      suspend_devices_and_enter - suspend devices and enter the desired system
 197  *                                  sleep state.
 198  *      @state:           state to enter
 199  */
 200 int suspend_devices_and_enter(suspend_state_t state)
 201 {
 202         int error;
 203         bool wakeup = false;
 204
 205         if (!suspend_ops)
 206                 return -ENOSYS;
 207
 208         trace_machine_suspend(state);
 209         if (suspend_ops->begin) {
 210                 error = suspend_ops->begin(state);
 211                 if (error)
 212                         goto Close;
 213         }
 214         suspend_console();
 215         suspend_test_start();
 216         error = dpm_suspend_start(PMSG_SUSPEND);
 217         if (error) {
 218                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 219                 goto Recover_platform;
 220         }
 221         suspend_test_finish("suspend devices");
 222         if (suspend_test(TEST_DEVICES))
 223                 goto Recover_platform;
 224
 225         do {
 226                 error = suspend_enter(state, &wakeup);
 227         } while (!error && !wakeup
 228                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 229
 230  Resume_devices:
 231         suspend_test_start();
 232         dpm_resume_end(PMSG_RESUME);
 233         suspend_test_finish("resume devices");
 234         resume_console();
 235  Close:
 236         if (suspend_ops->end)
 237                 suspend_ops->end();
 238         trace_machine_suspend(PWR_EVENT_EXIT);
 239         return error;
 240
 241  Recover_platform:
 242         if (suspend_ops->recover)
 243                 suspend_ops->recover();
 244         goto Resume_devices;
 245 }
 246
 247 /**
 248  *      suspend_finish - Do final work before exiting suspend sequence.
 249  *
 250  *      Call platform code to clean up, restart processes, and free the
 251  *      console that we've allocated. This is not called for suspend-to-disk.
 252  */
 253 static void suspend_finish(void)
 254 {
 255         suspend_thaw_processes();
 256         pm_notifier_call_chain(PM_POST_SUSPEND);
 257         pm_restore_console();
 258 }
 259
 260 /**
 261  *      enter_state - Do common work of entering low-power state.
 262  *      @state:         pm_state structure for state we're entering.
 263  *
 264  *      Make sure we're the only ones trying to enter a sleep state. Fail
 265  *      if someone has beat us to it, since we don't want anything weird to
 266  *      happen when we wake up.
 267  *      Then, do the setup for suspend, enter the state, and cleaup (after
 268  *      we've woken up).
 269  */
 270 int enter_state(suspend_state_t state)
 271 {
 272         int error;
 273
 274         if (!valid_state(state))
 275                 return -ENODEV;
 276
 277         if (!mutex_trylock(&pm_mutex))
 278                 return -EBUSY;
 279
 280         printk(KERN_INFO "PM: Syncing filesystems ... ");
 281         sys_sync();
 282         printk("done.\n");
 283
 284         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 285         error = suspend_prepare();
 286         if (error)
 287                 goto Unlock;
 288
 289         if (suspend_test(TEST_FREEZER))
 290                 goto Finish;
 291
 292         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 293         pm_restrict_gfp_mask();
 294         error = suspend_devices_and_enter(state);
 295         pm_restore_gfp_mask();
 296
 297  Finish:
 298         pr_debug("PM: Finishing wakeup.\n");
 299         suspend_finish();
 300  Unlock:
 301         mutex_unlock(&pm_mutex);
 302         return error;
 303 }
 304
 305 /**
 306  *      pm_suspend - Externally visible function for suspending system.
 307  *      @state:         Enumerated value of state to enter.
 308  *
 309  *      Determine whether or not value is within range, get state
 310  *      structure, and enter (above).
 311  */
 312 int pm_suspend(suspend_state_t state)
 313 {
 314         int ret;
 315         if (state > PM_SUSPEND_ON && state < PM_SUSPEND_MAX) {
 316                 ret = enter_state(state);
 317                 if (ret) {
 318                         suspend_stats.fail++;
 319                         dpm_save_failed_errno(ret);
 320                 } else
 321                         suspend_stats.success++;
 322                 return ret;
 323         }
 324         return -EINVAL;
 325 }
 326 EXPORT_SYMBOL(pm_suspend);