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 <linux/ftrace.h>
  28 #include <linux/rtc.h>
  29 #include <trace/events/power.h>
  30
  31 #include "power.h"
  32
  33 struct pm_sleep_state pm_states[PM_SUSPEND_MAX] = {
  34         [PM_SUSPEND_FREEZE] = { .label = "freeze", .state = PM_SUSPEND_FREEZE },
  35         [PM_SUSPEND_STANDBY] = { .label = "standby", },
  36         [PM_SUSPEND_MEM] = { .label = "mem", },
  37 };
  38
  39 static const struct platform_suspend_ops *suspend_ops;
  40
  41 static bool need_suspend_ops(suspend_state_t state)
  42 {
  43         return !!(state > PM_SUSPEND_FREEZE);
  44 }
  45
  46 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
  47 static bool suspend_freeze_wake;
  48
  49 static void freeze_begin(void)
  50 {
  51         suspend_freeze_wake = false;
  52 }
  53
  54 static void freeze_enter(void)
  55 {
  56         wait_event(suspend_freeze_wait_head, suspend_freeze_wake);
  57 }
  58
  59 void freeze_wake(void)
  60 {
  61         suspend_freeze_wake = true;
  62         wake_up(&suspend_freeze_wait_head);
  63 }
  64 EXPORT_SYMBOL_GPL(freeze_wake);
  65
  66 static bool valid_state(suspend_state_t state)
  67 {
  68         /*
  69          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
  70          * support and need to be valid to the low level
  71          * implementation, no valid callback implies that none are valid.
  72          */
  73         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  74 }
  75
  76 /**
  77  * suspend_set_ops - Set the global suspend method table.
  78  * @ops: Suspend operations to use.
  79  */
  80 void suspend_set_ops(const struct platform_suspend_ops *ops)
  81 {
  82         suspend_state_t i;
  83
  84         lock_system_sleep();
  85
  86         suspend_ops = ops;
  87         for (i = PM_SUSPEND_STANDBY; i <= PM_SUSPEND_MEM; i++)
  88                 pm_states[i].state = valid_state(i) ? i : 0;
  89
  90         unlock_system_sleep();
  91 }
  92 EXPORT_SYMBOL_GPL(suspend_set_ops);
  93
  94 /**
  95  * suspend_valid_only_mem - Generic memory-only valid callback.
  96  *
  97  * Platform drivers that implement mem suspend only and only need to check for
  98  * that in their .valid() callback can use this instead of rolling their own
  99  * .valid() callback.
 100  */
 101 int suspend_valid_only_mem(suspend_state_t state)
 102 {
 103         return state == PM_SUSPEND_MEM;
 104 }
 105 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 106
 107 static int suspend_test(int level)
 108 {
 109 #ifdef CONFIG_PM_DEBUG
 110         if (pm_test_level == level) {
 111                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
 112                 mdelay(5000);
 113                 return 1;
 114         }
 115 #endif /* !CONFIG_PM_DEBUG */
 116         return 0;
 117 }
 118
 119 /**
 120  * suspend_prepare - Prepare for entering system sleep state.
 121  *
 122  * Common code run for every system sleep state that can be entered (except for
 123  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 124  * freeze processes.
 125  */
 126 static int suspend_prepare(suspend_state_t state)
 127 {
 128         int error;
 129
 130         if (need_suspend_ops(state) && (!suspend_ops || !suspend_ops->enter))
 131                 return -EPERM;
 132
 133         pm_prepare_console();
 134
 135         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 136         if (error)
 137                 goto Finish;
 138
 139         error = suspend_freeze_processes();
 140         if (!error)
 141                 return 0;
 142
 143         suspend_stats.failed_freeze++;
 144         dpm_save_failed_step(SUSPEND_FREEZE);
 145  Finish:
 146         pm_notifier_call_chain(PM_POST_SUSPEND);
 147         pm_restore_console();
 148         return error;
 149 }
 150
 151 /* default implementation */
 152 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 153 {
 154         local_irq_disable();
 155 }
 156
 157 /* default implementation */
 158 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 159 {
 160         local_irq_enable();
 161 }
 162
 163 /**
 164  * suspend_enter - Make the system enter the given sleep state.
 165  * @state: System sleep state to enter.
 166  * @wakeup: Returns information that the sleep state should not be re-entered.
 167  *
 168  * This function should be called after devices have been suspended.
 169  */
 170 static int suspend_enter(suspend_state_t state, bool *wakeup)
 171 {
 172         int error;
 173
 174         if (need_suspend_ops(state) && suspend_ops->prepare) {
 175                 error = suspend_ops->prepare();
 176                 if (error)
 177                         goto Platform_finish;
 178         }
 179
 180         error = dpm_suspend_end(PMSG_SUSPEND);
 181         if (error) {
 182                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 183                 goto Platform_finish;
 184         }
 185
 186         if (need_suspend_ops(state) && suspend_ops->prepare_late) {
 187                 error = suspend_ops->prepare_late();
 188                 if (error)
 189                         goto Platform_wake;
 190         }
 191
 192         if (suspend_test(TEST_PLATFORM))
 193                 goto Platform_wake;
 194
 195         /*
 196          * PM_SUSPEND_FREEZE equals
 197          * frozen processes + suspended devices + idle processors.
 198          * Thus we should invoke freeze_enter() soon after
 199          * all the devices are suspended.
 200          */
 201         if (state == PM_SUSPEND_FREEZE) {
 202                 freeze_enter();
 203                 goto Platform_wake;
 204         }
 205
 206         error = disable_nonboot_cpus();
 207         if (error || suspend_test(TEST_CPUS))
 208                 goto Enable_cpus;
 209
 210         arch_suspend_disable_irqs();
 211         BUG_ON(!irqs_disabled());
 212
 213         error = syscore_suspend();
 214         if (!error) {
 215                 *wakeup = pm_wakeup_pending();
 216                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 217                         error = suspend_ops->enter(state);
 218                         events_check_enabled = false;
 219                 }
 220                 syscore_resume();
 221         }
 222
 223         arch_suspend_enable_irqs();
 224         BUG_ON(irqs_disabled());
 225
 226  Enable_cpus:
 227         enable_nonboot_cpus();
 228
 229  Platform_wake:
 230         if (need_suspend_ops(state) && suspend_ops->wake)
 231                 suspend_ops->wake();
 232
 233         dpm_resume_start(PMSG_RESUME);
 234
 235  Platform_finish:
 236         if (need_suspend_ops(state) && suspend_ops->finish)
 237                 suspend_ops->finish();
 238
 239         return error;
 240 }
 241
 242 /**
 243  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 244  * @state: System sleep state to enter.
 245  */
 246 int suspend_devices_and_enter(suspend_state_t state)
 247 {
 248         int error;
 249         bool wakeup = false;
 250
 251         if (need_suspend_ops(state) && !suspend_ops)
 252                 return -ENOSYS;
 253
 254         trace_machine_suspend(state);
 255         if (need_suspend_ops(state) && suspend_ops->begin) {
 256                 error = suspend_ops->begin(state);
 257                 if (error)
 258                         goto Close;
 259         }
 260         suspend_console();
 261         ftrace_stop();
 262         suspend_test_start();
 263         error = dpm_suspend_start(PMSG_SUSPEND);
 264         if (error) {
 265                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 266                 goto Recover_platform;
 267         }
 268         suspend_test_finish("suspend devices");
 269         if (suspend_test(TEST_DEVICES))
 270                 goto Recover_platform;
 271
 272         do {
 273                 error = suspend_enter(state, &wakeup);
 274         } while (!error && !wakeup && need_suspend_ops(state)
 275                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 276
 277  Resume_devices:
 278         suspend_test_start();
 279         dpm_resume_end(PMSG_RESUME);
 280         suspend_test_finish("resume devices");
 281         ftrace_start();
 282         resume_console();
 283  Close:
 284         if (need_suspend_ops(state) && suspend_ops->end)
 285                 suspend_ops->end();
 286         trace_machine_suspend(PWR_EVENT_EXIT);
 287         return error;
 288
 289  Recover_platform:
 290         if (need_suspend_ops(state) && suspend_ops->recover)
 291                 suspend_ops->recover();
 292         goto Resume_devices;
 293 }
 294
 295 /**
 296  * suspend_finish - Clean up before finishing the suspend sequence.
 297  *
 298  * Call platform code to clean up, restart processes, and free the console that
 299  * we've allocated. This routine is not called for hibernation.
 300  */
 301 static void suspend_finish(void)
 302 {
 303         suspend_thaw_processes();
 304         pm_notifier_call_chain(PM_POST_SUSPEND);
 305         pm_restore_console();
 306 }
 307
 308 /**
 309  * enter_state - Do common work needed to enter system sleep state.
 310  * @state: System sleep state to enter.
 311  *
 312  * Make sure that no one else is trying to put the system into a sleep state.
 313  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 314  * system enter the given sleep state and clean up after wakeup.
 315  */
 316 static int enter_state(suspend_state_t state)
 317 {
 318         int error;
 319
 320         if (state == PM_SUSPEND_FREEZE) {
 321 #ifdef CONFIG_PM_DEBUG
 322                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 323                         pr_warning("PM: Unsupported test mode for freeze state,"
 324                                    "please choose none/freezer/devices/platform.\n");
 325                         return -EAGAIN;
 326                 }
 327 #endif
 328         } else if (!valid_state(state)) {
 329                 return -EINVAL;
 330         }
 331         if (!mutex_trylock(&pm_mutex))
 332                 return -EBUSY;
 333
 334         if (state == PM_SUSPEND_FREEZE)
 335                 freeze_begin();
 336
 337         printk(KERN_INFO "PM: Syncing filesystems ... ");
 338         sys_sync();
 339         printk("done.\n");
 340
 341         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state].label);
 342         error = suspend_prepare(state);
 343         if (error)
 344                 goto Unlock;
 345
 346         if (suspend_test(TEST_FREEZER))
 347                 goto Finish;
 348
 349         pr_debug("PM: Entering %s sleep\n", pm_states[state].label);
 350         pm_restrict_gfp_mask();
 351         error = suspend_devices_and_enter(state);
 352         pm_restore_gfp_mask();
 353
 354  Finish:
 355         pr_debug("PM: Finishing wakeup.\n");
 356         suspend_finish();
 357  Unlock:
 358         mutex_unlock(&pm_mutex);
 359         return error;
 360 }
 361
 362 static void pm_suspend_marker(char *annotation)
 363 {
 364         struct timespec ts;
 365         struct rtc_time tm;
 366
 367         getnstimeofday(&ts);
 368         rtc_time_to_tm(ts.tv_sec, &tm);
 369         pr_info("PM: suspend %s %d-%02d-%02d %02d:%02d:%02d.%09lu UTC\n",
 370                 annotation, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 371                 tm.tm_hour, tm.tm_min, tm.tm_sec, ts.tv_nsec);
 372 }
 373
 374 /**
 375  * pm_suspend - Externally visible function for suspending the system.
 376  * @state: System sleep state to enter.
 377  *
 378  * Check if the value of @state represents one of the supported states,
 379  * execute enter_state() and update system suspend statistics.
 380  */
 381 int pm_suspend(suspend_state_t state)
 382 {
 383         int error;
 384
 385         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 386                 return -EINVAL;
 387
 388         pm_suspend_marker("entry");
 389         error = enter_state(state);
 390         if (error) {
 391                 suspend_stats.fail++;
 392                 dpm_save_failed_errno(error);
 393         } else {
 394                 suspend_stats.success++;
 395         }
 396         pm_suspend_marker("exit");
 397         return error;
 398 }
 399 EXPORT_SYMBOL(pm_suspend);