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