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 #include <linux/moduleparam.h>
  32
  33 #include "power.h"
  34
  35 const char *pm_labels[] = { "mem", "standby", "freeze", NULL };
  36 const char *pm_states[PM_SUSPEND_MAX];
  37
  38 unsigned int pm_suspend_global_flags;
  39 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
  40
  41 static const struct platform_suspend_ops *suspend_ops;
  42 static const struct platform_freeze_ops *freeze_ops;
  43 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
  44
  45 enum freeze_state __read_mostly suspend_freeze_state;
  46 static DEFINE_SPINLOCK(suspend_freeze_lock);
  47
  48 void freeze_set_ops(const struct platform_freeze_ops *ops)
  49 {
  50         lock_system_sleep();
  51         freeze_ops = ops;
  52         unlock_system_sleep();
  53 }
  54
  55 static void freeze_begin(void)
  56 {
  57         suspend_freeze_state = FREEZE_STATE_NONE;
  58 }
  59
  60 static void freeze_enter(void)
  61 {
  62         spin_lock_irq(&suspend_freeze_lock);
  63         if (pm_wakeup_pending())
  64                 goto out;
  65
  66         suspend_freeze_state = FREEZE_STATE_ENTER;
  67         spin_unlock_irq(&suspend_freeze_lock);
  68
  69         get_online_cpus();
  70         cpuidle_resume();
  71
  72         /* Push all the CPUs into the idle loop. */
  73         wake_up_all_idle_cpus();
  74         pr_debug("PM: suspend-to-idle\n");
  75         /* Make the current CPU wait so it can enter the idle loop too. */
  76         wait_event(suspend_freeze_wait_head,
  77                    suspend_freeze_state == FREEZE_STATE_WAKE);
  78         pr_debug("PM: resume from suspend-to-idle\n");
  79
  80         cpuidle_pause();
  81         put_online_cpus();
  82
  83         spin_lock_irq(&suspend_freeze_lock);
  84
  85  out:
  86         suspend_freeze_state = FREEZE_STATE_NONE;
  87         spin_unlock_irq(&suspend_freeze_lock);
  88 }
  89
  90 void freeze_wake(void)
  91 {
  92         unsigned long flags;
  93
  94         spin_lock_irqsave(&suspend_freeze_lock, flags);
  95         if (suspend_freeze_state > FREEZE_STATE_NONE) {
  96                 suspend_freeze_state = FREEZE_STATE_WAKE;
  97                 wake_up(&suspend_freeze_wait_head);
  98         }
  99         spin_unlock_irqrestore(&suspend_freeze_lock, flags);
 100 }
 101 EXPORT_SYMBOL_GPL(freeze_wake);
 102
 103 static bool valid_state(suspend_state_t state)
 104 {
 105         /*
 106          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
 107          * support and need to be valid to the low level
 108          * implementation, no valid callback implies that none are valid.
 109          */
 110         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
 111 }
 112
 113 /*
 114  * If this is set, the "mem" label always corresponds to the deepest sleep state
 115  * available, the "standby" label corresponds to the second deepest sleep state
 116  * available (if any), and the "freeze" label corresponds to the remaining
 117  * available sleep state (if there is one).
 118  */
 119 static bool relative_states;
 120
 121 static int __init sleep_states_setup(char *str)
 122 {
 123         relative_states = !strncmp(str, "1", 1);
 124         pm_states[PM_SUSPEND_FREEZE] = pm_labels[relative_states ? 0 : 2];
 125         return 1;
 126 }
 127
 128 __setup("relative_sleep_states=", sleep_states_setup);
 129
 130 /**
 131  * suspend_set_ops - Set the global suspend method table.
 132  * @ops: Suspend operations to use.
 133  */
 134 void suspend_set_ops(const struct platform_suspend_ops *ops)
 135 {
 136         suspend_state_t i;
 137         int j = 0;
 138
 139         lock_system_sleep();
 140
 141         suspend_ops = ops;
 142         for (i = PM_SUSPEND_MEM; i >= PM_SUSPEND_STANDBY; i--)
 143                 if (valid_state(i)) {
 144                         pm_states[i] = pm_labels[j++];
 145                 } else if (!relative_states) {
 146                         pm_states[i] = NULL;
 147                         j++;
 148                 }
 149
 150         pm_states[PM_SUSPEND_FREEZE] = pm_labels[j];
 151
 152         unlock_system_sleep();
 153 }
 154 EXPORT_SYMBOL_GPL(suspend_set_ops);
 155
 156 /**
 157  * suspend_valid_only_mem - Generic memory-only valid callback.
 158  *
 159  * Platform drivers that implement mem suspend only and only need to check for
 160  * that in their .valid() callback can use this instead of rolling their own
 161  * .valid() callback.
 162  */
 163 int suspend_valid_only_mem(suspend_state_t state)
 164 {
 165         return state == PM_SUSPEND_MEM;
 166 }
 167 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 168
 169 static bool sleep_state_supported(suspend_state_t state)
 170 {
 171         return state == PM_SUSPEND_FREEZE || (suspend_ops && suspend_ops->enter);
 172 }
 173
 174 static int platform_suspend_prepare(suspend_state_t state)
 175 {
 176         return state != PM_SUSPEND_FREEZE && suspend_ops->prepare ?
 177                 suspend_ops->prepare() : 0;
 178 }
 179
 180 static int platform_suspend_prepare_late(suspend_state_t state)
 181 {
 182         return state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->prepare ?
 183                 freeze_ops->prepare() : 0;
 184 }
 185
 186 static int platform_suspend_prepare_noirq(suspend_state_t state)
 187 {
 188         return state != PM_SUSPEND_FREEZE && suspend_ops->prepare_late ?
 189                 suspend_ops->prepare_late() : 0;
 190 }
 191
 192 static void platform_resume_noirq(suspend_state_t state)
 193 {
 194         if (state != PM_SUSPEND_FREEZE && suspend_ops->wake)
 195                 suspend_ops->wake();
 196 }
 197
 198 static void platform_resume_early(suspend_state_t state)
 199 {
 200         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->restore)
 201                 freeze_ops->restore();
 202 }
 203
 204 static void platform_resume_finish(suspend_state_t state)
 205 {
 206         if (state != PM_SUSPEND_FREEZE && suspend_ops->finish)
 207                 suspend_ops->finish();
 208 }
 209
 210 static int platform_suspend_begin(suspend_state_t state)
 211 {
 212         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->begin)
 213                 return freeze_ops->begin();
 214         else if (suspend_ops->begin)
 215                 return suspend_ops->begin(state);
 216         else
 217                 return 0;
 218 }
 219
 220 static void platform_resume_end(suspend_state_t state)
 221 {
 222         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->end)
 223                 freeze_ops->end();
 224         else if (suspend_ops->end)
 225                 suspend_ops->end();
 226 }
 227
 228 static void platform_recover(suspend_state_t state)
 229 {
 230         if (state != PM_SUSPEND_FREEZE && suspend_ops->recover)
 231                 suspend_ops->recover();
 232 }
 233
 234 static bool platform_suspend_again(suspend_state_t state)
 235 {
 236         return state != PM_SUSPEND_FREEZE && suspend_ops->suspend_again ?
 237                 suspend_ops->suspend_again() : false;
 238 }
 239
 240 #ifdef CONFIG_PM_DEBUG
 241 static unsigned int pm_test_delay = 5;
 242 module_param(pm_test_delay, uint, 0644);
 243 MODULE_PARM_DESC(pm_test_delay,
 244                  "Number of seconds to wait before resuming from suspend test");
 245 #endif
 246
 247 static int suspend_test(int level)
 248 {
 249 #ifdef CONFIG_PM_DEBUG
 250         if (pm_test_level == level) {
 251                 pr_info("suspend debug: Waiting for %d second(s).\n",
 252                                 pm_test_delay);
 253                 mdelay(pm_test_delay * 1000);
 254                 return 1;
 255         }
 256 #endif /* !CONFIG_PM_DEBUG */
 257         return 0;
 258 }
 259
 260 /**
 261  * suspend_prepare - Prepare for entering system sleep state.
 262  *
 263  * Common code run for every system sleep state that can be entered (except for
 264  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 265  * freeze processes.
 266  */
 267 static int suspend_prepare(suspend_state_t state)
 268 {
 269         int error, nr_calls = 0;
 270
 271         if (!sleep_state_supported(state))
 272                 return -EPERM;
 273
 274         pm_prepare_console();
 275
 276         error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls);
 277         if (error) {
 278                 nr_calls--;
 279                 goto Finish;
 280         }
 281
 282         trace_suspend_resume(TPS("freeze_processes"), 0, true);
 283         error = suspend_freeze_processes();
 284         trace_suspend_resume(TPS("freeze_processes"), 0, false);
 285         if (!error)
 286                 return 0;
 287
 288         suspend_stats.failed_freeze++;
 289         dpm_save_failed_step(SUSPEND_FREEZE);
 290  Finish:
 291         __pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL);
 292         pm_restore_console();
 293         return error;
 294 }
 295
 296 /* default implementation */
 297 void __weak arch_suspend_disable_irqs(void)
 298 {
 299         local_irq_disable();
 300 }
 301
 302 /* default implementation */
 303 void __weak arch_suspend_enable_irqs(void)
 304 {
 305         local_irq_enable();
 306 }
 307
 308 /**
 309  * suspend_enter - Make the system enter the given sleep state.
 310  * @state: System sleep state to enter.
 311  * @wakeup: Returns information that the sleep state should not be re-entered.
 312  *
 313  * This function should be called after devices have been suspended.
 314  */
 315 static int suspend_enter(suspend_state_t state, bool *wakeup)
 316 {
 317         int error;
 318
 319         error = platform_suspend_prepare(state);
 320         if (error)
 321                 goto Platform_finish;
 322
 323         error = dpm_suspend_late(PMSG_SUSPEND);
 324         if (error) {
 325                 pr_err("PM: late suspend of devices failed\n");
 326                 goto Platform_finish;
 327         }
 328         error = platform_suspend_prepare_late(state);
 329         if (error)
 330                 goto Devices_early_resume;
 331
 332         error = dpm_suspend_noirq(PMSG_SUSPEND);
 333         if (error) {
 334                 pr_err("PM: noirq suspend of devices failed\n");
 335                 goto Platform_early_resume;
 336         }
 337         error = platform_suspend_prepare_noirq(state);
 338         if (error)
 339                 goto Platform_wake;
 340
 341         if (suspend_test(TEST_PLATFORM))
 342                 goto Platform_wake;
 343
 344         /*
 345          * PM_SUSPEND_FREEZE equals
 346          * frozen processes + suspended devices + idle processors.
 347          * Thus we should invoke freeze_enter() soon after
 348          * all the devices are suspended.
 349          */
 350         if (state == PM_SUSPEND_FREEZE) {
 351                 trace_suspend_resume(TPS("machine_suspend"), state, true);
 352                 freeze_enter();
 353                 trace_suspend_resume(TPS("machine_suspend"), state, false);
 354                 goto Platform_wake;
 355         }
 356
 357         error = disable_nonboot_cpus();
 358         if (error || suspend_test(TEST_CPUS))
 359                 goto Enable_cpus;
 360
 361         arch_suspend_disable_irqs();
 362         BUG_ON(!irqs_disabled());
 363
 364         error = syscore_suspend();
 365         if (!error) {
 366                 *wakeup = pm_wakeup_pending();
 367                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 368                         trace_suspend_resume(TPS("machine_suspend"),
 369                                 state, true);
 370                         error = suspend_ops->enter(state);
 371                         trace_suspend_resume(TPS("machine_suspend"),
 372                                 state, false);
 373                         events_check_enabled = false;
 374                 } else if (*wakeup) {
 375                         error = -EBUSY;
 376                 }
 377                 syscore_resume();
 378         }
 379
 380         arch_suspend_enable_irqs();
 381         BUG_ON(irqs_disabled());
 382
 383  Enable_cpus:
 384         enable_nonboot_cpus();
 385
 386  Platform_wake:
 387         platform_resume_noirq(state);
 388         dpm_resume_noirq(PMSG_RESUME);
 389
 390  Platform_early_resume:
 391         platform_resume_early(state);
 392
 393  Devices_early_resume:
 394         dpm_resume_early(PMSG_RESUME);
 395
 396  Platform_finish:
 397         platform_resume_finish(state);
 398         return error;
 399 }
 400
 401 /**
 402  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 403  * @state: System sleep state to enter.
 404  */
 405 int suspend_devices_and_enter(suspend_state_t state)
 406 {
 407         int error;
 408         bool wakeup = false;
 409
 410         if (!sleep_state_supported(state))
 411                 return -ENOSYS;
 412
 413         error = platform_suspend_begin(state);
 414         if (error)
 415                 goto Close;
 416
 417         suspend_console();
 418         suspend_test_start();
 419         error = dpm_suspend_start(PMSG_SUSPEND);
 420         if (error) {
 421                 pr_err("PM: Some devices failed to suspend, or early wake event detected\n");
 422                 goto Recover_platform;
 423         }
 424         suspend_test_finish("suspend devices");
 425         if (suspend_test(TEST_DEVICES))
 426                 goto Recover_platform;
 427
 428         do {
 429                 error = suspend_enter(state, &wakeup);
 430         } while (!error && !wakeup && platform_suspend_again(state));
 431
 432  Resume_devices:
 433         suspend_test_start();
 434         dpm_resume_end(PMSG_RESUME);
 435         suspend_test_finish("resume devices");
 436         trace_suspend_resume(TPS("resume_console"), state, true);
 437         resume_console();
 438         trace_suspend_resume(TPS("resume_console"), state, false);
 439
 440  Close:
 441         platform_resume_end(state);
 442         return error;
 443
 444  Recover_platform:
 445         platform_recover(state);
 446         goto Resume_devices;
 447 }
 448
 449 /**
 450  * suspend_finish - Clean up before finishing the suspend sequence.
 451  *
 452  * Call platform code to clean up, restart processes, and free the console that
 453  * we've allocated. This routine is not called for hibernation.
 454  */
 455 static void suspend_finish(void)
 456 {
 457         suspend_thaw_processes();
 458         pm_notifier_call_chain(PM_POST_SUSPEND);
 459         pm_restore_console();
 460 }
 461
 462 /**
 463  * enter_state - Do common work needed to enter system sleep state.
 464  * @state: System sleep state to enter.
 465  *
 466  * Make sure that no one else is trying to put the system into a sleep state.
 467  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 468  * system enter the given sleep state and clean up after wakeup.
 469  */
 470 static int enter_state(suspend_state_t state)
 471 {
 472         int error;
 473
 474         trace_suspend_resume(TPS("suspend_enter"), state, true);
 475         if (state == PM_SUSPEND_FREEZE) {
 476 #ifdef CONFIG_PM_DEBUG
 477                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 478                         pr_warn("PM: Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
 479                         return -EAGAIN;
 480                 }
 481 #endif
 482         } else if (!valid_state(state)) {
 483                 return -EINVAL;
 484         }
 485         if (!mutex_trylock(&pm_mutex))
 486                 return -EBUSY;
 487
 488         if (state == PM_SUSPEND_FREEZE)
 489                 freeze_begin();
 490
 491 #ifndef CONFIG_SUSPEND_SKIP_SYNC
 492         trace_suspend_resume(TPS("sync_filesystems"), 0, true);
 493         printk(KERN_INFO "PM: Syncing filesystems ... ");
 494         sys_sync();
 495         printk("done.\n");
 496         trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 497 #endif
 498
 499         pr_debug("PM: Preparing system for sleep (%s)\n", pm_states[state]);
 500         pm_suspend_clear_flags();
 501         error = suspend_prepare(state);
 502         if (error)
 503                 goto Unlock;
 504
 505         if (suspend_test(TEST_FREEZER))
 506                 goto Finish;
 507
 508         trace_suspend_resume(TPS("suspend_enter"), state, false);
 509         pr_debug("PM: Suspending system (%s)\n", pm_states[state]);
 510         pm_restrict_gfp_mask();
 511         error = suspend_devices_and_enter(state);
 512         pm_restore_gfp_mask();
 513
 514  Finish:
 515         pr_debug("PM: Finishing wakeup.\n");
 516         suspend_finish();
 517  Unlock:
 518         mutex_unlock(&pm_mutex);
 519         return error;
 520 }
 521
 522 /**
 523  * pm_suspend - Externally visible function for suspending the system.
 524  * @state: System sleep state to enter.
 525  *
 526  * Check if the value of @state represents one of the supported states,
 527  * execute enter_state() and update system suspend statistics.
 528  */
 529 int pm_suspend(suspend_state_t state)
 530 {
 531         int error;
 532
 533         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 534                 return -EINVAL;
 535
 536         error = enter_state(state);
 537         if (error) {
 538                 suspend_stats.fail++;
 539                 dpm_save_failed_errno(error);
 540         } else {
 541                 suspend_stats.success++;
 542         }
 543         return error;
 544 }
 545 EXPORT_SYMBOL(pm_suspend);