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