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 struct pm_sleep_state pm_states[PM_SUSPEND_MAX] = {
  35         [PM_SUSPEND_FREEZE] = { .label = "freeze", .state = PM_SUSPEND_FREEZE },
  36         [PM_SUSPEND_STANDBY] = { .label = "standby", },
  37         [PM_SUSPEND_MEM] = { .label = "mem", },
  38 };
  39
  40 static const struct platform_suspend_ops *suspend_ops;
  41 static const struct platform_freeze_ops *freeze_ops;
  42
  43 static bool need_suspend_ops(suspend_state_t state)
  44 {
  45         return state > PM_SUSPEND_FREEZE;
  46 }
  47
  48 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
  49 static bool suspend_freeze_wake;
  50
  51 void freeze_set_ops(const struct platform_freeze_ops *ops)
  52 {
  53         lock_system_sleep();
  54         freeze_ops = ops;
  55         unlock_system_sleep();
  56 }
  57
  58 static void freeze_begin(void)
  59 {
  60         suspend_freeze_wake = false;
  61 }
  62
  63 static void freeze_enter(void)
  64 {
  65         cpuidle_use_deepest_state(true);
  66         cpuidle_resume();
  67         wait_event(suspend_freeze_wait_head, suspend_freeze_wake);
  68         cpuidle_pause();
  69         cpuidle_use_deepest_state(false);
  70 }
  71
  72 void freeze_wake(void)
  73 {
  74         suspend_freeze_wake = true;
  75         wake_up(&suspend_freeze_wait_head);
  76 }
  77 EXPORT_SYMBOL_GPL(freeze_wake);
  78
  79 static bool valid_state(suspend_state_t state)
  80 {
  81         /*
  82          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
  83          * support and need to be valid to the low level
  84          * implementation, no valid callback implies that none are valid.
  85          */
  86         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
  87 }
  88
  89 /*
  90  * If this is set, the "mem" label always corresponds to the deepest sleep state
  91  * available, the "standby" label corresponds to the second deepest sleep state
  92  * available (if any), and the "freeze" label corresponds to the remaining
  93  * available sleep state (if there is one).
  94  */
  95 static bool relative_states;
  96
  97 static int __init sleep_states_setup(char *str)
  98 {
  99         relative_states = !strncmp(str, "1", 1);
 100         if (relative_states) {
 101                 pm_states[PM_SUSPEND_MEM].state = PM_SUSPEND_FREEZE;
 102                 pm_states[PM_SUSPEND_FREEZE].state = 0;
 103         }
 104         return 1;
 105 }
 106
 107 __setup("relative_sleep_states=", sleep_states_setup);
 108
 109 /**
 110  * suspend_set_ops - Set the global suspend method table.
 111  * @ops: Suspend operations to use.
 112  */
 113 void suspend_set_ops(const struct platform_suspend_ops *ops)
 114 {
 115         suspend_state_t i;
 116         int j = PM_SUSPEND_MAX - 1;
 117
 118         lock_system_sleep();
 119
 120         suspend_ops = ops;
 121         for (i = PM_SUSPEND_MEM; i >= PM_SUSPEND_STANDBY; i--)
 122                 if (valid_state(i))
 123                         pm_states[j--].state = i;
 124                 else if (!relative_states)
 125                         pm_states[j--].state = 0;
 126
 127         pm_states[j--].state = PM_SUSPEND_FREEZE;
 128         while (j >= PM_SUSPEND_MIN)
 129                 pm_states[j--].state = 0;
 130
 131         unlock_system_sleep();
 132 }
 133 EXPORT_SYMBOL_GPL(suspend_set_ops);
 134
 135 /**
 136  * suspend_valid_only_mem - Generic memory-only valid callback.
 137  *
 138  * Platform drivers that implement mem suspend only and only need to check for
 139  * that in their .valid() callback can use this instead of rolling their own
 140  * .valid() callback.
 141  */
 142 int suspend_valid_only_mem(suspend_state_t state)
 143 {
 144         return state == PM_SUSPEND_MEM;
 145 }
 146 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 147
 148 static int suspend_test(int level)
 149 {
 150 #ifdef CONFIG_PM_DEBUG
 151         if (pm_test_level == level) {
 152                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
 153                 mdelay(5000);
 154                 return 1;
 155         }
 156 #endif /* !CONFIG_PM_DEBUG */
 157         return 0;
 158 }
 159
 160 /**
 161  * suspend_prepare - Prepare for entering system sleep state.
 162  *
 163  * Common code run for every system sleep state that can be entered (except for
 164  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 165  * freeze processes.
 166  */
 167 static int suspend_prepare(suspend_state_t state)
 168 {
 169         int error;
 170
 171         if (need_suspend_ops(state) && (!suspend_ops || !suspend_ops->enter))
 172                 return -EPERM;
 173
 174         pm_prepare_console();
 175
 176         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 177         if (error)
 178                 goto Finish;
 179
 180         error = suspend_freeze_processes();
 181         if (!error)
 182                 return 0;
 183
 184         suspend_stats.failed_freeze++;
 185         dpm_save_failed_step(SUSPEND_FREEZE);
 186  Finish:
 187         pm_notifier_call_chain(PM_POST_SUSPEND);
 188         pm_restore_console();
 189         return error;
 190 }
 191
 192 /* default implementation */
 193 void __weak arch_suspend_disable_irqs(void)
 194 {
 195         local_irq_disable();
 196 }
 197
 198 /* default implementation */
 199 void __weak arch_suspend_enable_irqs(void)
 200 {
 201         local_irq_enable();
 202 }
 203
 204 /**
 205  * suspend_enter - Make the system enter the given sleep state.
 206  * @state: System sleep state to enter.
 207  * @wakeup: Returns information that the sleep state should not be re-entered.
 208  *
 209  * This function should be called after devices have been suspended.
 210  */
 211 static int suspend_enter(suspend_state_t state, bool *wakeup)
 212 {
 213         int error;
 214
 215         if (need_suspend_ops(state) && suspend_ops->prepare) {
 216                 error = suspend_ops->prepare();
 217                 if (error)
 218                         goto Platform_finish;
 219         }
 220
 221         error = dpm_suspend_end(PMSG_SUSPEND);
 222         if (error) {
 223                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 224                 goto Platform_finish;
 225         }
 226
 227         if (need_suspend_ops(state) && suspend_ops->prepare_late) {
 228                 error = suspend_ops->prepare_late();
 229                 if (error)
 230                         goto Platform_wake;
 231         }
 232
 233         if (suspend_test(TEST_PLATFORM))
 234                 goto Platform_wake;
 235
 236         /*
 237          * PM_SUSPEND_FREEZE equals
 238          * frozen processes + suspended devices + idle processors.
 239          * Thus we should invoke freeze_enter() soon after
 240          * all the devices are suspended.
 241          */
 242         if (state == PM_SUSPEND_FREEZE) {
 243                 freeze_enter();
 244                 goto Platform_wake;
 245         }
 246
 247         ftrace_stop();
 248         error = disable_nonboot_cpus();
 249         if (error || suspend_test(TEST_CPUS))
 250                 goto Enable_cpus;
 251
 252         arch_suspend_disable_irqs();
 253         BUG_ON(!irqs_disabled());
 254
 255         error = syscore_suspend();
 256         if (!error) {
 257                 *wakeup = pm_wakeup_pending();
 258                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 259                         error = suspend_ops->enter(state);
 260                         events_check_enabled = false;
 261                 }
 262                 syscore_resume();
 263         }
 264
 265         arch_suspend_enable_irqs();
 266         BUG_ON(irqs_disabled());
 267
 268  Enable_cpus:
 269         enable_nonboot_cpus();
 270         ftrace_start();
 271
 272  Platform_wake:
 273         if (need_suspend_ops(state) && suspend_ops->wake)
 274                 suspend_ops->wake();
 275
 276         dpm_resume_start(PMSG_RESUME);
 277
 278  Platform_finish:
 279         if (need_suspend_ops(state) && suspend_ops->finish)
 280                 suspend_ops->finish();
 281
 282         return error;
 283 }
 284
 285 /**
 286  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 287  * @state: System sleep state to enter.
 288  */
 289 int suspend_devices_and_enter(suspend_state_t state)
 290 {
 291         int error;
 292         bool wakeup = false;
 293
 294         if (need_suspend_ops(state) && !suspend_ops)
 295                 return -ENOSYS;
 296
 297         trace_machine_suspend(state);
 298         if (need_suspend_ops(state) && suspend_ops->begin) {
 299                 error = suspend_ops->begin(state);
 300                 if (error)
 301                         goto Close;
 302         } else if (state == PM_SUSPEND_FREEZE && freeze_ops->begin) {
 303                 error = freeze_ops->begin();
 304                 if (error)
 305                         goto Close;
 306         }
 307         suspend_console();
 308         suspend_test_start();
 309         error = dpm_suspend_start(PMSG_SUSPEND);
 310         if (error) {
 311                 pr_err("PM: Some devices failed to suspend, or early wake event detected\n");
 312                 goto Recover_platform;
 313         }
 314         suspend_test_finish("suspend devices");
 315         if (suspend_test(TEST_DEVICES))
 316                 goto Recover_platform;
 317
 318         do {
 319                 error = suspend_enter(state, &wakeup);
 320         } while (!error && !wakeup && need_suspend_ops(state)
 321                 && suspend_ops->suspend_again && suspend_ops->suspend_again());
 322
 323  Resume_devices:
 324         suspend_test_start();
 325         dpm_resume_end(PMSG_RESUME);
 326         suspend_test_finish("resume devices");
 327         resume_console();
 328  Close:
 329         if (need_suspend_ops(state) && suspend_ops->end)
 330                 suspend_ops->end();
 331         else if (state == PM_SUSPEND_FREEZE && freeze_ops->end)
 332                 freeze_ops->end();
 333
 334         trace_machine_suspend(PWR_EVENT_EXIT);
 335         return error;
 336
 337  Recover_platform:
 338         if (need_suspend_ops(state) && suspend_ops->recover)
 339                 suspend_ops->recover();
 340         goto Resume_devices;
 341 }
 342
 343 /**
 344  * suspend_finish - Clean up before finishing the suspend sequence.
 345  *
 346  * Call platform code to clean up, restart processes, and free the console that
 347  * we've allocated. This routine is not called for hibernation.
 348  */
 349 static void suspend_finish(void)
 350 {
 351         suspend_thaw_processes();
 352         pm_notifier_call_chain(PM_POST_SUSPEND);
 353         pm_restore_console();
 354 }
 355
 356 /**
 357  * enter_state - Do common work needed to enter system sleep state.
 358  * @state: System sleep state to enter.
 359  *
 360  * Make sure that no one else is trying to put the system into a sleep state.
 361  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 362  * system enter the given sleep state and clean up after wakeup.
 363  */
 364 static int enter_state(suspend_state_t state)
 365 {
 366         int error;
 367
 368         if (state == PM_SUSPEND_FREEZE) {
 369 #ifdef CONFIG_PM_DEBUG
 370                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 371                         pr_warning("PM: Unsupported test mode for freeze state,"
 372                                    "please choose none/freezer/devices/platform.\n");
 373                         return -EAGAIN;
 374                 }
 375 #endif
 376         } else if (!valid_state(state)) {
 377                 return -EINVAL;
 378         }
 379         if (!mutex_trylock(&pm_mutex))
 380                 return -EBUSY;
 381
 382         if (state == PM_SUSPEND_FREEZE)
 383                 freeze_begin();
 384
 385         printk(KERN_INFO "PM: Syncing filesystems ... ");
 386         sys_sync();
 387         printk("done.\n");
 388
 389         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state].label);
 390         error = suspend_prepare(state);
 391         if (error)
 392                 goto Unlock;
 393
 394         if (suspend_test(TEST_FREEZER))
 395                 goto Finish;
 396
 397         pr_debug("PM: Entering %s sleep\n", pm_states[state].label);
 398         pm_restrict_gfp_mask();
 399         error = suspend_devices_and_enter(state);
 400         pm_restore_gfp_mask();
 401
 402  Finish:
 403         pr_debug("PM: Finishing wakeup.\n");
 404         suspend_finish();
 405  Unlock:
 406         mutex_unlock(&pm_mutex);
 407         return error;
 408 }
 409
 410 /**
 411  * pm_suspend - Externally visible function for suspending the system.
 412  * @state: System sleep state to enter.
 413  *
 414  * Check if the value of @state represents one of the supported states,
 415  * execute enter_state() and update system suspend statistics.
 416  */
 417 int pm_suspend(suspend_state_t state)
 418 {
 419         int error;
 420
 421         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 422                 return -EINVAL;
 423
 424         error = enter_state(state);
 425         if (error) {
 426                 suspend_stats.fail++;
 427                 dpm_save_failed_errno(error);
 428         } else {
 429                 suspend_stats.success++;
 430         }
 431         return error;
 432 }
 433 EXPORT_SYMBOL(pm_suspend);