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/cpuidle.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 <linux/ftrace.h>
  29 #include <trace/events/power.h>
  30 #include <linux/compiler.h>
  31
  32 #include "power.h"
  33
  34 const char *const pm_states[PM_SUSPEND_MAX] = {
  35         [PM_SUSPEND_FREEZE]     = "freeze",
  36         [PM_SUSPEND_STANDBY]    = "standby",
  37         [PM_SUSPEND_MEM]        = "mem",
  38 };
  39
  40 static const struct platform_suspend_ops *suspend_ops;
  41
  42 static bool need_suspend_ops(suspend_state_t state)
  43 {
  44         return state > PM_SUSPEND_FREEZE;
  45 }
  46
  47 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
  48 static bool suspend_freeze_wake;
  49
  50 static void freeze_begin(void)
  51 {
  52         suspend_freeze_wake = false;
  53 }
  54
  55 static void freeze_enter(void)
  56 {
  57         cpuidle_resume();
  58         wait_event(suspend_freeze_wait_head, suspend_freeze_wake);
  59         cpuidle_pause();
  60 }
  61
  62 void freeze_wake(void)
  63 {
  64         suspend_freeze_wake = true;
  65         wake_up(&suspend_freeze_wait_head);
  66 }
  67 EXPORT_SYMBOL_GPL(freeze_wake);
  68
  69 /**
  70  * suspend_set_ops - Set the global suspend method table.
  71  * @ops: Suspend operations to use.
  72  */
  73 void suspend_set_ops(const struct platform_suspend_ops *ops)
  74 {
  75         lock_system_sleep();
  76         suspend_ops = ops;
  77         unlock_system_sleep();
  78 }
  79 EXPORT_SYMBOL_GPL(suspend_set_ops);
  80
  81 bool valid_state(suspend_state_t state)
  82 {
  83         if (state == PM_SUSPEND_FREEZE) {
  84 #ifdef CONFIG_PM_DEBUG
  85                 if (pm_test_level != TEST_NONE &&
  86                     pm_test_level != TEST_FREEZER &&
  87                     pm_test_level != TEST_DEVICES &&
  88                     pm_test_level != TEST_PLATFORM) {
  89                         printk(KERN_WARNING "Unsupported pm_test mode for "
  90                                         "freeze state, please choose "
  91                                         "none/freezer/devices/platform.\n");
  92                         return false;
  93                 }
  94 #endif
  95                         return true;
  96         }
  97         /*
  98          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEMORY states need lowlevel
  99          * support and need to be valid to the lowlevel
 100          * implementation, no valid callback implies that none are valid.
 101          */
 102         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
 103 }
 104
 105 /**
 106  * suspend_valid_only_mem - Generic memory-only valid callback.
 107  *
 108  * Platform drivers that implement mem suspend only and only need to check for
 109  * that in their .valid() callback can use this instead of rolling their own
 110  * .valid() callback.
 111  */
 112 int suspend_valid_only_mem(suspend_state_t state)
 113 {
 114         return state == PM_SUSPEND_MEM;
 115 }
 116 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 117
 118 static int suspend_test(int level)
 119 {
 120 #ifdef CONFIG_PM_DEBUG
 121         if (pm_test_level == level) {
 122                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
 123                 mdelay(5000);
 124                 return 1;
 125         }
 126 #endif /* !CONFIG_PM_DEBUG */
 127         return 0;
 128 }
 129
 130 /**
 131  * suspend_prepare - Prepare for entering system sleep state.
 132  *
 133  * Common code run for every system sleep state that can be entered (except for
 134  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 135  * freeze processes.
 136  */
 137 static int suspend_prepare(suspend_state_t state)
 138 {
 139         int error;
 140
 141         if (need_suspend_ops(state) && (!suspend_ops || !suspend_ops->enter))
 142                 return -EPERM;
 143
 144         pm_prepare_console();
 145
 146         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 147         if (error)
 148                 goto Finish;
 149
 150         error = suspend_freeze_processes();
 151         if (!error)
 152                 return 0;
 153
 154         suspend_stats.failed_freeze++;
 155         dpm_save_failed_step(SUSPEND_FREEZE);
 156  Finish:
 157         pm_notifier_call_chain(PM_POST_SUSPEND);
 158         pm_restore_console();
 159         return error;
 160 }
 161
 162 /* default implementation */
 163 void __weak arch_suspend_disable_irqs(void)
 164 {
 165         local_irq_disable();
 166 }
 167
 168 /* default implementation */
 169 void __weak arch_suspend_enable_irqs(void)
 170 {
 171         local_irq_enable();
 172 }
 173
 174 /**
 175  * suspend_enter - Make the system enter the given sleep state.
 176  * @state: System sleep state to enter.
 177  * @wakeup: Returns information that the sleep state should not be re-entered.
 178  *
 179  * This function should be called after devices have been suspended.
 180  */
 181 static int suspend_enter(suspend_state_t state, bool *wakeup)
 182 {
 183         int error;
 184
 185         if (need_suspend_ops(state) && suspend_ops->prepare) {
 186                 error = suspend_ops->prepare();
 187                 if (error)
 188                         goto Platform_finish;
 189         }
 190
 191         error = dpm_suspend_end(PMSG_SUSPEND);
 192         if (error) {
 193                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 194                 goto Platform_finish;
 195         }
 196
 197         if (need_suspend_ops(state) && suspend_ops->prepare_late) {
 198                 error = suspend_ops->prepare_late();
 199                 if (error)
 200                         goto Platform_wake;
 201         }
 202
 203         if (suspend_test(TEST_PLATFORM))
 204                 goto Platform_wake;
 205
 206         /*
 207          * PM_SUSPEND_FREEZE equals
 208          * frozen processes + suspended devices + idle processors.
 209          * Thus we should invoke freeze_enter() soon after
 210          * all the devices are suspended.
 211          */
 212         if (state == PM_SUSPEND_FREEZE) {
 213                 freeze_enter();
 214                 goto Platform_wake;
 215         }
 216
 217         ftrace_stop();
 218         error = disable_nonboot_cpus();
 219         if (error || suspend_test(TEST_CPUS))
 220                 goto Enable_cpus;
 221
 222         arch_suspend_disable_irqs();
 223         BUG_ON(!irqs_disabled());
 224
 225         error = syscore_suspend();
 226         if (!error) {
 227                 *wakeup = pm_wakeup_pending();
 228                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 229                         error = suspend_ops->enter(state);
 230                         events_check_enabled = false;
 231                 }
 232                 syscore_resume();
 233         }
 234
 235         arch_suspend_enable_irqs();
 236         BUG_ON(irqs_disabled());
 237
 238  Enable_cpus:
 239         enable_nonboot_cpus();
 240         ftrace_start();
 241
 242  Platform_wake:
 243         if (need_suspend_ops(state) && suspend_ops->wake)
 244                 suspend_ops->wake();
 245
 246         dpm_resume_start(PMSG_RESUME);
 247
 248  Platform_finish:
 249         if (need_suspend_ops(state) && suspend_ops->finish)
 250                 suspend_ops->finish();
 251
 252         return error;
 253 }
 254
 255 /**
 256  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 257  * @state: System sleep state to enter.
 258  */
 259 int suspend_devices_and_enter(suspend_state_t state)
 260 {
 261         int error;
 262         bool wakeup = false;
 263
 264         if (need_suspend_ops(state) && !suspend_ops)
 265                 return -ENOSYS;
 266
 267         trace_machine_suspend(state);
 268         if (need_suspend_ops(state) && suspend_ops->begin) {
 269                 error = suspend_ops->begin(state);
 270                 if (error)
 271                         goto Close;
 272         }
 273         suspend_console();
 274         suspend_test_start();
 275         error = dpm_suspend_start(PMSG_SUSPEND);
 276         if (error) {
 277                 pr_err("PM: Some devices failed to suspend, or early wake event detected\n");
 278                 goto Recover_platform;
 279         }
 280         suspend_test_finish("suspend devices");
 281         if (suspend_test(TEST_DEVICES))
 282                 goto Recover_platform;
 283
 284         do {
 285                 error = suspend_enter(state, &wakeup);
 286         } while (!error && !wakeup && need_suspend_ops(state)
 287                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 288
 289  Resume_devices:
 290         suspend_test_start();
 291         dpm_resume_end(PMSG_RESUME);
 292         suspend_test_finish("resume devices");
 293         resume_console();
 294  Close:
 295         if (need_suspend_ops(state) && suspend_ops->end)
 296                 suspend_ops->end();
 297         trace_machine_suspend(PWR_EVENT_EXIT);
 298         return error;
 299
 300  Recover_platform:
 301         if (need_suspend_ops(state) && suspend_ops->recover)
 302                 suspend_ops->recover();
 303         goto Resume_devices;
 304 }
 305
 306 /**
 307  * suspend_finish - Clean up before finishing the suspend sequence.
 308  *
 309  * Call platform code to clean up, restart processes, and free the console that
 310  * we've allocated. This routine is not called for hibernation.
 311  */
 312 static void suspend_finish(void)
 313 {
 314         suspend_thaw_processes();
 315         pm_notifier_call_chain(PM_POST_SUSPEND);
 316         pm_restore_console();
 317 }
 318
 319 /**
 320  * enter_state - Do common work needed to enter system sleep state.
 321  * @state: System sleep state to enter.
 322  *
 323  * Make sure that no one else is trying to put the system into a sleep state.
 324  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 325  * system enter the given sleep state and clean up after wakeup.
 326  */
 327 static int enter_state(suspend_state_t state)
 328 {
 329         int error;
 330
 331         if (!valid_state(state))
 332                 return -ENODEV;
 333
 334         if (!mutex_trylock(&pm_mutex))
 335                 return -EBUSY;
 336
 337         if (state == PM_SUSPEND_FREEZE)
 338                 freeze_begin();
 339
 340         printk(KERN_INFO "PM: Syncing filesystems ... ");
 341         sys_sync();
 342         printk("done.\n");
 343
 344         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 345         error = suspend_prepare(state);
 346         if (error)
 347                 goto Unlock;
 348
 349         if (suspend_test(TEST_FREEZER))
 350                 goto Finish;
 351
 352         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 353         pm_restrict_gfp_mask();
 354         error = suspend_devices_and_enter(state);
 355         pm_restore_gfp_mask();
 356
 357  Finish:
 358         pr_debug("PM: Finishing wakeup.\n");
 359         suspend_finish();
 360  Unlock:
 361         mutex_unlock(&pm_mutex);
 362         return error;
 363 }
 364
 365 /**
 366  * pm_suspend - Externally visible function for suspending the system.
 367  * @state: System sleep state to enter.
 368  *
 369  * Check if the value of @state represents one of the supported states,
 370  * execute enter_state() and update system suspend statistics.
 371  */
 372 int pm_suspend(suspend_state_t state)
 373 {
 374         int error;
 375
 376         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 377                 return -EINVAL;
 378
 379         error = enter_state(state);
 380         if (error) {
 381                 suspend_stats.fail++;
 382                 dpm_save_failed_errno(error);
 383         } else {
 384                 suspend_stats.success++;
 385         }
 386         return error;
 387 }
 388 EXPORT_SYMBOL(pm_suspend);