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 *pm_labels[] = { "mem", "standby", "freeze", NULL };
  35 const char *pm_states[PM_SUSPEND_MAX];
  36
  37 static const struct platform_suspend_ops *suspend_ops;
  38 static const struct platform_freeze_ops *freeze_ops;
  39 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
  40
  41 enum freeze_state __read_mostly suspend_freeze_state;
  42 static DEFINE_SPINLOCK(suspend_freeze_lock);
  43
  44 void freeze_set_ops(const struct platform_freeze_ops *ops)
  45 {
  46         lock_system_sleep();
  47         freeze_ops = ops;
  48         unlock_system_sleep();
  49 }
  50
  51 static void freeze_begin(void)
  52 {
  53         suspend_freeze_state = FREEZE_STATE_NONE;
  54 }
  55
  56 static void freeze_enter(void)
  57 {
  58         spin_lock_irq(&suspend_freeze_lock);
  59         if (pm_wakeup_pending())
  60                 goto out;
  61
  62         suspend_freeze_state = FREEZE_STATE_ENTER;
  63         spin_unlock_irq(&suspend_freeze_lock);
  64
  65         get_online_cpus();
  66         cpuidle_resume();
  67
  68         /* Push all the CPUs into the idle loop. */
  69         wake_up_all_idle_cpus();
  70         pr_debug("PM: suspend-to-idle\n");
  71         /* Make the current CPU wait so it can enter the idle loop too. */
  72         wait_event(suspend_freeze_wait_head,
  73                    suspend_freeze_state == FREEZE_STATE_WAKE);
  74         pr_debug("PM: resume from suspend-to-idle\n");
  75
  76         cpuidle_pause();
  77         put_online_cpus();
  78
  79         spin_lock_irq(&suspend_freeze_lock);
  80
  81  out:
  82         suspend_freeze_state = FREEZE_STATE_NONE;
  83         spin_unlock_irq(&suspend_freeze_lock);
  84 }
  85
  86 void freeze_wake(void)
  87 {
  88         unsigned long flags;
  89
  90         spin_lock_irqsave(&suspend_freeze_lock, flags);
  91         if (suspend_freeze_state > FREEZE_STATE_NONE) {
  92                 suspend_freeze_state = FREEZE_STATE_WAKE;
  93                 wake_up(&suspend_freeze_wait_head);
  94         }
  95         spin_unlock_irqrestore(&suspend_freeze_lock, flags);
  96 }
  97 EXPORT_SYMBOL_GPL(freeze_wake);
  98
  99 static bool valid_state(suspend_state_t state)
 100 {
 101         /*
 102          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
 103          * support and need to be valid to the low level
 104          * implementation, no valid callback implies that none are valid.
 105          */
 106         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
 107 }
 108
 109 /*
 110  * If this is set, the "mem" label always corresponds to the deepest sleep state
 111  * available, the "standby" label corresponds to the second deepest sleep state
 112  * available (if any), and the "freeze" label corresponds to the remaining
 113  * available sleep state (if there is one).
 114  */
 115 static bool relative_states;
 116
 117 static int __init sleep_states_setup(char *str)
 118 {
 119         relative_states = !strncmp(str, "1", 1);
 120         pm_states[PM_SUSPEND_FREEZE] = pm_labels[relative_states ? 0 : 2];
 121         return 1;
 122 }
 123
 124 __setup("relative_sleep_states=", sleep_states_setup);
 125
 126 /**
 127  * suspend_set_ops - Set the global suspend method table.
 128  * @ops: Suspend operations to use.
 129  */
 130 void suspend_set_ops(const struct platform_suspend_ops *ops)
 131 {
 132         suspend_state_t i;
 133         int j = 0;
 134
 135         lock_system_sleep();
 136
 137         suspend_ops = ops;
 138         for (i = PM_SUSPEND_MEM; i >= PM_SUSPEND_STANDBY; i--)
 139                 if (valid_state(i)) {
 140                         pm_states[i] = pm_labels[j++];
 141                 } else if (!relative_states) {
 142                         pm_states[i] = NULL;
 143                         j++;
 144                 }
 145
 146         pm_states[PM_SUSPEND_FREEZE] = pm_labels[j];
 147
 148         unlock_system_sleep();
 149 }
 150 EXPORT_SYMBOL_GPL(suspend_set_ops);
 151
 152 /**
 153  * suspend_valid_only_mem - Generic memory-only valid callback.
 154  *
 155  * Platform drivers that implement mem suspend only and only need to check for
 156  * that in their .valid() callback can use this instead of rolling their own
 157  * .valid() callback.
 158  */
 159 int suspend_valid_only_mem(suspend_state_t state)
 160 {
 161         return state == PM_SUSPEND_MEM;
 162 }
 163 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 164
 165 static bool sleep_state_supported(suspend_state_t state)
 166 {
 167         return state == PM_SUSPEND_FREEZE || (suspend_ops && suspend_ops->enter);
 168 }
 169
 170 static int platform_suspend_prepare(suspend_state_t state)
 171 {
 172         return state != PM_SUSPEND_FREEZE && suspend_ops->prepare ?
 173                 suspend_ops->prepare() : 0;
 174 }
 175
 176 static int platform_suspend_prepare_late(suspend_state_t state)
 177 {
 178         return state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->prepare ?
 179                 freeze_ops->prepare() : 0;
 180 }
 181
 182 static int platform_suspend_prepare_noirq(suspend_state_t state)
 183 {
 184         return state != PM_SUSPEND_FREEZE && suspend_ops->prepare_late ?
 185                 suspend_ops->prepare_late() : 0;
 186 }
 187
 188 static void platform_resume_noirq(suspend_state_t state)
 189 {
 190         if (state != PM_SUSPEND_FREEZE && suspend_ops->wake)
 191                 suspend_ops->wake();
 192 }
 193
 194 static void platform_resume_early(suspend_state_t state)
 195 {
 196         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->restore)
 197                 freeze_ops->restore();
 198 }
 199
 200 static void platform_resume_finish(suspend_state_t state)
 201 {
 202         if (state != PM_SUSPEND_FREEZE && suspend_ops->finish)
 203                 suspend_ops->finish();
 204 }
 205
 206 static int platform_suspend_begin(suspend_state_t state)
 207 {
 208         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->begin)
 209                 return freeze_ops->begin();
 210         else if (suspend_ops->begin)
 211                 return suspend_ops->begin(state);
 212         else
 213                 return 0;
 214 }
 215
 216 static void platform_resume_end(suspend_state_t state)
 217 {
 218         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->end)
 219                 freeze_ops->end();
 220         else if (suspend_ops->end)
 221                 suspend_ops->end();
 222 }
 223
 224 static void platform_recover(suspend_state_t state)
 225 {
 226         if (state != PM_SUSPEND_FREEZE && suspend_ops->recover)
 227                 suspend_ops->recover();
 228 }
 229
 230 static bool platform_suspend_again(suspend_state_t state)
 231 {
 232         return state != PM_SUSPEND_FREEZE && suspend_ops->suspend_again ?
 233                 suspend_ops->suspend_again() : false;
 234 }
 235
 236 static int suspend_test(int level)
 237 {
 238 #ifdef CONFIG_PM_DEBUG
 239         if (pm_test_level == level) {
 240                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
 241                 mdelay(5000);
 242                 return 1;
 243         }
 244 #endif /* !CONFIG_PM_DEBUG */
 245         return 0;
 246 }
 247
 248 /**
 249  * suspend_prepare - Prepare for entering system sleep state.
 250  *
 251  * Common code run for every system sleep state that can be entered (except for
 252  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 253  * freeze processes.
 254  */
 255 static int suspend_prepare(suspend_state_t state)
 256 {
 257         int error;
 258
 259         if (!sleep_state_supported(state))
 260                 return -EPERM;
 261
 262         pm_prepare_console();
 263
 264         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 265         if (error)
 266                 goto Finish;
 267
 268         trace_suspend_resume(TPS("freeze_processes"), 0, true);
 269         error = suspend_freeze_processes();
 270         trace_suspend_resume(TPS("freeze_processes"), 0, false);
 271         if (!error)
 272                 return 0;
 273
 274         suspend_stats.failed_freeze++;
 275         dpm_save_failed_step(SUSPEND_FREEZE);
 276  Finish:
 277         pm_notifier_call_chain(PM_POST_SUSPEND);
 278         pm_restore_console();
 279         return error;
 280 }
 281
 282 /* default implementation */
 283 void __weak arch_suspend_disable_irqs(void)
 284 {
 285         local_irq_disable();
 286 }
 287
 288 /* default implementation */
 289 void __weak arch_suspend_enable_irqs(void)
 290 {
 291         local_irq_enable();
 292 }
 293
 294 /**
 295  * suspend_enter - Make the system enter the given sleep state.
 296  * @state: System sleep state to enter.
 297  * @wakeup: Returns information that the sleep state should not be re-entered.
 298  *
 299  * This function should be called after devices have been suspended.
 300  */
 301 static int suspend_enter(suspend_state_t state, bool *wakeup)
 302 {
 303         int error;
 304
 305         error = platform_suspend_prepare(state);
 306         if (error)
 307                 goto Platform_finish;
 308
 309         error = dpm_suspend_late(PMSG_SUSPEND);
 310         if (error) {
 311                 printk(KERN_ERR "PM: late suspend of devices failed\n");
 312                 goto Platform_finish;
 313         }
 314         error = platform_suspend_prepare_late(state);
 315         if (error)
 316                 goto Devices_early_resume;
 317
 318         error = dpm_suspend_noirq(PMSG_SUSPEND);
 319         if (error) {
 320                 printk(KERN_ERR "PM: noirq suspend of devices failed\n");
 321                 goto Platform_early_resume;
 322         }
 323         error = platform_suspend_prepare_noirq(state);
 324         if (error)
 325                 goto Platform_wake;
 326
 327         if (suspend_test(TEST_PLATFORM))
 328                 goto Platform_wake;
 329
 330         /*
 331          * PM_SUSPEND_FREEZE equals
 332          * frozen processes + suspended devices + idle processors.
 333          * Thus we should invoke freeze_enter() soon after
 334          * all the devices are suspended.
 335          */
 336         if (state == PM_SUSPEND_FREEZE) {
 337                 trace_suspend_resume(TPS("machine_suspend"), state, true);
 338                 freeze_enter();
 339                 trace_suspend_resume(TPS("machine_suspend"), state, false);
 340                 goto Platform_wake;
 341         }
 342
 343         error = disable_nonboot_cpus();
 344         if (error || suspend_test(TEST_CPUS))
 345                 goto Enable_cpus;
 346
 347         arch_suspend_disable_irqs();
 348         BUG_ON(!irqs_disabled());
 349
 350         error = syscore_suspend();
 351         if (!error) {
 352                 *wakeup = pm_wakeup_pending();
 353                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 354                         trace_suspend_resume(TPS("machine_suspend"),
 355                                 state, true);
 356                         error = suspend_ops->enter(state);
 357                         trace_suspend_resume(TPS("machine_suspend"),
 358                                 state, false);
 359                         events_check_enabled = false;
 360                 }
 361                 syscore_resume();
 362         }
 363
 364         arch_suspend_enable_irqs();
 365         BUG_ON(irqs_disabled());
 366
 367  Enable_cpus:
 368         enable_nonboot_cpus();
 369
 370  Platform_wake:
 371         platform_resume_noirq(state);
 372         dpm_resume_noirq(PMSG_RESUME);
 373
 374  Platform_early_resume:
 375         platform_resume_early(state);
 376
 377  Devices_early_resume:
 378         dpm_resume_early(PMSG_RESUME);
 379
 380  Platform_finish:
 381         platform_resume_finish(state);
 382         return error;
 383 }
 384
 385 /**
 386  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 387  * @state: System sleep state to enter.
 388  */
 389 int suspend_devices_and_enter(suspend_state_t state)
 390 {
 391         int error;
 392         bool wakeup = false;
 393
 394         if (!sleep_state_supported(state))
 395                 return -ENOSYS;
 396
 397         error = platform_suspend_begin(state);
 398         if (error)
 399                 goto Close;
 400
 401         suspend_console();
 402         suspend_test_start();
 403         error = dpm_suspend_start(PMSG_SUSPEND);
 404         if (error) {
 405                 pr_err("PM: Some devices failed to suspend, or early wake event detected\n");
 406                 goto Recover_platform;
 407         }
 408         suspend_test_finish("suspend devices");
 409         if (suspend_test(TEST_DEVICES))
 410                 goto Recover_platform;
 411
 412         do {
 413                 error = suspend_enter(state, &wakeup);
 414         } while (!error && !wakeup && platform_suspend_again(state));
 415
 416  Resume_devices:
 417         suspend_test_start();
 418         dpm_resume_end(PMSG_RESUME);
 419         suspend_test_finish("resume devices");
 420         trace_suspend_resume(TPS("resume_console"), state, true);
 421         resume_console();
 422         trace_suspend_resume(TPS("resume_console"), state, false);
 423
 424  Close:
 425         platform_resume_end(state);
 426         return error;
 427
 428  Recover_platform:
 429         platform_recover(state);
 430         goto Resume_devices;
 431 }
 432
 433 /**
 434  * suspend_finish - Clean up before finishing the suspend sequence.
 435  *
 436  * Call platform code to clean up, restart processes, and free the console that
 437  * we've allocated. This routine is not called for hibernation.
 438  */
 439 static void suspend_finish(void)
 440 {
 441         suspend_thaw_processes();
 442         pm_notifier_call_chain(PM_POST_SUSPEND);
 443         pm_restore_console();
 444 }
 445
 446 /**
 447  * enter_state - Do common work needed to enter system sleep state.
 448  * @state: System sleep state to enter.
 449  *
 450  * Make sure that no one else is trying to put the system into a sleep state.
 451  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 452  * system enter the given sleep state and clean up after wakeup.
 453  */
 454 static int enter_state(suspend_state_t state)
 455 {
 456         int error;
 457
 458         trace_suspend_resume(TPS("suspend_enter"), state, true);
 459         if (state == PM_SUSPEND_FREEZE) {
 460 #ifdef CONFIG_PM_DEBUG
 461                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 462                         pr_warning("PM: Unsupported test mode for freeze state,"
 463                                    "please choose none/freezer/devices/platform.\n");
 464                         return -EAGAIN;
 465                 }
 466 #endif
 467         } else if (!valid_state(state)) {
 468                 return -EINVAL;
 469         }
 470         if (!mutex_trylock(&pm_mutex))
 471                 return -EBUSY;
 472
 473         if (state == PM_SUSPEND_FREEZE)
 474                 freeze_begin();
 475
 476         trace_suspend_resume(TPS("sync_filesystems"), 0, true);
 477         printk(KERN_INFO "PM: Syncing filesystems ... ");
 478         sys_sync();
 479         printk("done.\n");
 480         trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 481
 482         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 483         error = suspend_prepare(state);
 484         if (error)
 485                 goto Unlock;
 486
 487         if (suspend_test(TEST_FREEZER))
 488                 goto Finish;
 489
 490         trace_suspend_resume(TPS("suspend_enter"), state, false);
 491         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 492         pm_restrict_gfp_mask();
 493         error = suspend_devices_and_enter(state);
 494         pm_restore_gfp_mask();
 495
 496  Finish:
 497         pr_debug("PM: Finishing wakeup.\n");
 498         suspend_finish();
 499  Unlock:
 500         mutex_unlock(&pm_mutex);
 501         return error;
 502 }
 503
 504 /**
 505  * pm_suspend - Externally visible function for suspending the system.
 506  * @state: System sleep state to enter.
 507  *
 508  * Check if the value of @state represents one of the supported states,
 509  * execute enter_state() and update system suspend statistics.
 510  */
 511 int pm_suspend(suspend_state_t state)
 512 {
 513         int error;
 514
 515         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 516                 return -EINVAL;
 517
 518         error = enter_state(state);
 519         if (error) {
 520                 suspend_stats.fail++;
 521                 dpm_save_failed_errno(error);
 522         } else {
 523                 suspend_stats.success++;
 524         }
 525         return error;
 526 }
 527 EXPORT_SYMBOL(pm_suspend);