kernel/power/main.c

   1 /*
   2  * kernel/power/main.c - PM subsystem core functionality.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  *
   7  * This file is released under the GPLv2
   8  *
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/suspend.h>
  13 #include <linux/kobject.h>
  14 #include <linux/string.h>
  15 #include <linux/delay.h>
  16 #include <linux/errno.h>
  17 #include <linux/kmod.h>
  18 #include <linux/init.h>
  19 #include <linux/console.h>
  20 #include <linux/cpu.h>
  21 #include <linux/resume-trace.h>
  22 #include <linux/freezer.h>
  23 #include <linux/vmstat.h>
  24 #include <linux/syscalls.h>
  25
  26 #include "power.h"
  27
  28 DEFINE_MUTEX(pm_mutex);
  29
  30 unsigned int pm_flags;
  31 EXPORT_SYMBOL(pm_flags);
  32
  33 #ifdef CONFIG_PM_SLEEP
  34
  35 /* Routines for PM-transition notifications */
  36
  37 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
  38
  39 int register_pm_notifier(struct notifier_block *nb)
  40 {
  41         return blocking_notifier_chain_register(&pm_chain_head, nb);
  42 }
  43 EXPORT_SYMBOL_GPL(register_pm_notifier);
  44
  45 int unregister_pm_notifier(struct notifier_block *nb)
  46 {
  47         return blocking_notifier_chain_unregister(&pm_chain_head, nb);
  48 }
  49 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
  50
  51 int pm_notifier_call_chain(unsigned long val)
  52 {
  53         return (blocking_notifier_call_chain(&pm_chain_head, val, NULL)
  54                         == NOTIFY_BAD) ? -EINVAL : 0;
  55 }
  56
  57 #ifdef CONFIG_PM_DEBUG
  58 int pm_test_level = TEST_NONE;
  59
  60 static const char * const pm_tests[__TEST_AFTER_LAST] = {
  61         [TEST_NONE] = "none",
  62         [TEST_CORE] = "core",
  63         [TEST_CPUS] = "processors",
  64         [TEST_PLATFORM] = "platform",
  65         [TEST_DEVICES] = "devices",
  66         [TEST_FREEZER] = "freezer",
  67 };
  68
  69 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
  70                                 char *buf)
  71 {
  72         char *s = buf;
  73         int level;
  74
  75         for (level = TEST_FIRST; level <= TEST_MAX; level++)
  76                 if (pm_tests[level]) {
  77                         if (level == pm_test_level)
  78                                 s += sprintf(s, "[%s] ", pm_tests[level]);
  79                         else
  80                                 s += sprintf(s, "%s ", pm_tests[level]);
  81                 }
  82
  83         if (s != buf)
  84                 /* convert the last space to a newline */
  85                 *(s-1) = '\n';
  86
  87         return (s - buf);
  88 }
  89
  90 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
  91                                 const char *buf, size_t n)
  92 {
  93         const char * const *s;
  94         int level;
  95         char *p;
  96         int len;
  97         int error = -EINVAL;
  98
  99         p = memchr(buf, '\n', n);
 100         len = p ? p - buf : n;
 101
 102         mutex_lock(&pm_mutex);
 103
 104         level = TEST_FIRST;
 105         for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
 106                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
 107                         pm_test_level = level;
 108                         error = 0;
 109                         break;
 110                 }
 111
 112         mutex_unlock(&pm_mutex);
 113
 114         return error ? error : n;
 115 }
 116
 117 power_attr(pm_test);
 118 #endif /* CONFIG_PM_DEBUG */
 119
 120 #endif /* CONFIG_PM_SLEEP */
 121
 122 #ifdef CONFIG_SUSPEND
 123
 124 static int suspend_test(int level)
 125 {
 126 #ifdef CONFIG_PM_DEBUG
 127         if (pm_test_level == level) {
 128                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
 129                 mdelay(5000);
 130                 return 1;
 131         }
 132 #endif /* !CONFIG_PM_DEBUG */
 133         return 0;
 134 }
 135
 136 #ifdef CONFIG_PM_TEST_SUSPEND
 137
 138 /*
 139  * We test the system suspend code by setting an RTC wakealarm a short
 140  * time in the future, then suspending.  Suspending the devices won't
 141  * normally take long ... some systems only need a few milliseconds.
 142  *
 143  * The time it takes is system-specific though, so when we test this
 144  * during system bootup we allow a LOT of time.
 145  */
 146 #define TEST_SUSPEND_SECONDS    5
 147
 148 static unsigned long suspend_test_start_time;
 149
 150 static void suspend_test_start(void)
 151 {
 152         /* FIXME Use better timebase than "jiffies", ideally a clocksource.
 153          * What we want is a hardware counter that will work correctly even
 154          * during the irqs-are-off stages of the suspend/resume cycle...
 155          */
 156         suspend_test_start_time = jiffies;
 157 }
 158
 159 static void suspend_test_finish(const char *label)
 160 {
 161         long nj = jiffies - suspend_test_start_time;
 162         unsigned msec;
 163
 164         msec = jiffies_to_msecs(abs(nj));
 165         pr_info("PM: %s took %d.%03d seconds\n", label,
 166                         msec / 1000, msec % 1000);
 167
 168         /* Warning on suspend means the RTC alarm period needs to be
 169          * larger -- the system was sooo slooowwww to suspend that the
 170          * alarm (should have) fired before the system went to sleep!
 171          *
 172          * Warning on either suspend or resume also means the system
 173          * has some performance issues.  The stack dump of a WARN_ON
 174          * is more likely to get the right attention than a printk...
 175          */
 176         WARN(msec > (TEST_SUSPEND_SECONDS * 1000), "Component: %s\n", label);
 177 }
 178
 179 #else
 180
 181 static void suspend_test_start(void)
 182 {
 183 }
 184
 185 static void suspend_test_finish(const char *label)
 186 {
 187 }
 188
 189 #endif
 190
 191 /* This is just an arbitrary number */
 192 #define FREE_PAGE_NUMBER (100)
 193
 194 static struct platform_suspend_ops *suspend_ops;
 195
 196 /**
 197  *      suspend_set_ops - Set the global suspend method table.
 198  *      @ops:   Pointer to ops structure.
 199  */
 200
 201 void suspend_set_ops(struct platform_suspend_ops *ops)
 202 {
 203         mutex_lock(&pm_mutex);
 204         suspend_ops = ops;
 205         mutex_unlock(&pm_mutex);
 206 }
 207
 208 /**
 209  * suspend_valid_only_mem - generic memory-only valid callback
 210  *
 211  * Platform drivers that implement mem suspend only and only need
 212  * to check for that in their .valid callback can use this instead
 213  * of rolling their own .valid callback.
 214  */
 215 int suspend_valid_only_mem(suspend_state_t state)
 216 {
 217         return state == PM_SUSPEND_MEM;
 218 }
 219
 220 /**
 221  *      suspend_prepare - Do prep work before entering low-power state.
 222  *
 223  *      This is common code that is called for each state that we're entering.
 224  *      Run suspend notifiers, allocate a console and stop all processes.
 225  */
 226 static int suspend_prepare(void)
 227 {
 228         int error;
 229         unsigned int free_pages;
 230
 231         if (!suspend_ops || !suspend_ops->enter)
 232                 return -EPERM;
 233
 234         pm_prepare_console();
 235
 236         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 237         if (error)
 238                 goto Finish;
 239
 240         error = usermodehelper_disable();
 241         if (error)
 242                 goto Finish;
 243
 244         if (suspend_freeze_processes()) {
 245                 error = -EAGAIN;
 246                 goto Thaw;
 247         }
 248
 249         free_pages = global_page_state(NR_FREE_PAGES);
 250         if (free_pages < FREE_PAGE_NUMBER) {
 251                 pr_debug("PM: free some memory\n");
 252                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
 253                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
 254                         error = -ENOMEM;
 255                         printk(KERN_ERR "PM: No enough memory\n");
 256                 }
 257         }
 258         if (!error)
 259                 return 0;
 260
 261  Thaw:
 262         suspend_thaw_processes();
 263         usermodehelper_enable();
 264  Finish:
 265         pm_notifier_call_chain(PM_POST_SUSPEND);
 266         pm_restore_console();
 267         return error;
 268 }
 269
 270 /* default implementation */
 271 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 272 {
 273         local_irq_disable();
 274 }
 275
 276 /* default implementation */
 277 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 278 {
 279         local_irq_enable();
 280 }
 281
 282 /**
 283  *      suspend_enter - enter the desired system sleep state.
 284  *      @state:         state to enter
 285  *
 286  *      This function should be called after devices have been suspended.
 287  */
 288 static int suspend_enter(suspend_state_t state)
 289 {
 290         int error;
 291
 292         if (suspend_ops->prepare) {
 293                 error = suspend_ops->prepare();
 294                 if (error)
 295                         return error;
 296         }
 297
 298         error = device_power_down(PMSG_SUSPEND);
 299         if (error) {
 300                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 301                 goto Platfrom_finish;
 302         }
 303
 304         if (suspend_ops->prepare_late) {
 305                 error = suspend_ops->prepare_late();
 306                 if (error)
 307                         goto Power_up_devices;
 308         }
 309
 310         if (suspend_test(TEST_PLATFORM))
 311                 goto Platform_wake;
 312
 313         error = disable_nonboot_cpus();
 314         if (error || suspend_test(TEST_CPUS))
 315                 goto Enable_cpus;
 316
 317         arch_suspend_disable_irqs();
 318         BUG_ON(!irqs_disabled());
 319
 320         error = sysdev_suspend(PMSG_SUSPEND);
 321         if (!error) {
 322                 if (!suspend_test(TEST_CORE))
 323                         error = suspend_ops->enter(state);
 324                 sysdev_resume();
 325         }
 326
 327         arch_suspend_enable_irqs();
 328         BUG_ON(irqs_disabled());
 329
 330  Enable_cpus:
 331         enable_nonboot_cpus();
 332
 333  Platform_wake:
 334         if (suspend_ops->wake)
 335                 suspend_ops->wake();
 336
 337  Power_up_devices:
 338         device_power_up(PMSG_RESUME);
 339
 340  Platfrom_finish:
 341         if (suspend_ops->finish)
 342                 suspend_ops->finish();
 343
 344         return error;
 345 }
 346
 347 /**
 348  *      suspend_devices_and_enter - suspend devices and enter the desired system
 349  *                                  sleep state.
 350  *      @state:           state to enter
 351  */
 352 int suspend_devices_and_enter(suspend_state_t state)
 353 {
 354         int error;
 355
 356         if (!suspend_ops)
 357                 return -ENOSYS;
 358
 359         if (suspend_ops->begin) {
 360                 error = suspend_ops->begin(state);
 361                 if (error)
 362                         goto Close;
 363         }
 364         suspend_console();
 365         suspend_test_start();
 366         error = device_suspend(PMSG_SUSPEND);
 367         if (error) {
 368                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 369                 goto Recover_platform;
 370         }
 371         suspend_test_finish("suspend devices");
 372         if (suspend_test(TEST_DEVICES))
 373                 goto Recover_platform;
 374
 375         suspend_enter(state);
 376
 377  Resume_devices:
 378         suspend_test_start();
 379         device_resume(PMSG_RESUME);
 380         suspend_test_finish("resume devices");
 381         resume_console();
 382  Close:
 383         if (suspend_ops->end)
 384                 suspend_ops->end();
 385         return error;
 386
 387  Recover_platform:
 388         if (suspend_ops->recover)
 389                 suspend_ops->recover();
 390         goto Resume_devices;
 391 }
 392
 393 /**
 394  *      suspend_finish - Do final work before exiting suspend sequence.
 395  *
 396  *      Call platform code to clean up, restart processes, and free the
 397  *      console that we've allocated. This is not called for suspend-to-disk.
 398  */
 399 static void suspend_finish(void)
 400 {
 401         suspend_thaw_processes();
 402         usermodehelper_enable();
 403         pm_notifier_call_chain(PM_POST_SUSPEND);
 404         pm_restore_console();
 405 }
 406
 407
 408
 409
 410 static const char * const pm_states[PM_SUSPEND_MAX] = {
 411         [PM_SUSPEND_STANDBY]    = "standby",
 412         [PM_SUSPEND_MEM]        = "mem",
 413 };
 414
 415 static inline int valid_state(suspend_state_t state)
 416 {
 417         /* All states need lowlevel support and need to be valid
 418          * to the lowlevel implementation, no valid callback
 419          * implies that none are valid. */
 420         if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
 421                 return 0;
 422         return 1;
 423 }
 424
 425
 426 /**
 427  *      enter_state - Do common work of entering low-power state.
 428  *      @state:         pm_state structure for state we're entering.
 429  *
 430  *      Make sure we're the only ones trying to enter a sleep state. Fail
 431  *      if someone has beat us to it, since we don't want anything weird to
 432  *      happen when we wake up.
 433  *      Then, do the setup for suspend, enter the state, and cleaup (after
 434  *      we've woken up).
 435  */
 436 static int enter_state(suspend_state_t state)
 437 {
 438         int error;
 439
 440         if (!valid_state(state))
 441                 return -ENODEV;
 442
 443         if (!mutex_trylock(&pm_mutex))
 444                 return -EBUSY;
 445
 446         printk(KERN_INFO "PM: Syncing filesystems ... ");
 447         sys_sync();
 448         printk("done.\n");
 449
 450         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 451         error = suspend_prepare();
 452         if (error)
 453                 goto Unlock;
 454
 455         if (suspend_test(TEST_FREEZER))
 456                 goto Finish;
 457
 458         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 459         error = suspend_devices_and_enter(state);
 460
 461  Finish:
 462         pr_debug("PM: Finishing wakeup.\n");
 463         suspend_finish();
 464  Unlock:
 465         mutex_unlock(&pm_mutex);
 466         return error;
 467 }
 468
 469
 470 /**
 471  *      pm_suspend - Externally visible function for suspending system.
 472  *      @state:         Enumerated value of state to enter.
 473  *
 474  *      Determine whether or not value is within range, get state
 475  *      structure, and enter (above).
 476  */
 477
 478 int pm_suspend(suspend_state_t state)
 479 {
 480         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 481                 return enter_state(state);
 482         return -EINVAL;
 483 }
 484
 485 EXPORT_SYMBOL(pm_suspend);
 486
 487 #endif /* CONFIG_SUSPEND */
 488
 489 struct kobject *power_kobj;
 490
 491 /**
 492  *      state - control system power state.
 493  *
 494  *      show() returns what states are supported, which is hard-coded to
 495  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 496  *      'disk' (Suspend-to-Disk).
 497  *
 498  *      store() accepts one of those strings, translates it into the
 499  *      proper enumerated value, and initiates a suspend transition.
 500  */
 501
 502 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
 503                           char *buf)
 504 {
 505         char *s = buf;
 506 #ifdef CONFIG_SUSPEND
 507         int i;
 508
 509         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 510                 if (pm_states[i] && valid_state(i))
 511                         s += sprintf(s,"%s ", pm_states[i]);
 512         }
 513 #endif
 514 #ifdef CONFIG_HIBERNATION
 515         s += sprintf(s, "%s\n", "disk");
 516 #else
 517         if (s != buf)
 518                 /* convert the last space to a newline */
 519                 *(s-1) = '\n';
 520 #endif
 521         return (s - buf);
 522 }
 523
 524 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
 525                            const char *buf, size_t n)
 526 {
 527 #ifdef CONFIG_SUSPEND
 528         suspend_state_t state = PM_SUSPEND_STANDBY;
 529         const char * const *s;
 530 #endif
 531         char *p;
 532         int len;
 533         int error = -EINVAL;
 534
 535         p = memchr(buf, '\n', n);
 536         len = p ? p - buf : n;
 537
 538         /* First, check if we are requested to hibernate */
 539         if (len == 4 && !strncmp(buf, "disk", len)) {
 540                 error = hibernate();
 541   goto Exit;
 542         }
 543
 544 #ifdef CONFIG_SUSPEND
 545         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 546                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
 547                         break;
 548         }
 549         if (state < PM_SUSPEND_MAX && *s)
 550                 error = enter_state(state);
 551 #endif
 552
 553  Exit:
 554         return error ? error : n;
 555 }
 556
 557 power_attr(state);
 558
 559 #ifdef CONFIG_PM_TRACE
 560 int pm_trace_enabled;
 561
 562 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
 563                              char *buf)
 564 {
 565         return sprintf(buf, "%d\n", pm_trace_enabled);
 566 }
 567
 568 static ssize_t
 569 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
 570                const char *buf, size_t n)
 571 {
 572         int val;
 573
 574         if (sscanf(buf, "%d", &val) == 1) {
 575                 pm_trace_enabled = !!val;
 576                 return n;
 577         }
 578         return -EINVAL;
 579 }
 580
 581 power_attr(pm_trace);
 582 #endif /* CONFIG_PM_TRACE */
 583
 584 static struct attribute * g[] = {
 585         &state_attr.attr,
 586 #ifdef CONFIG_PM_TRACE
 587         &pm_trace_attr.attr,
 588 #endif
 589 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)
 590         &pm_test_attr.attr,
 591 #endif
 592         NULL,
 593 };
 594
 595 static struct attribute_group attr_group = {
 596         .attrs = g,
 597 };
 598
 599
 600 static int __init pm_init(void)
 601 {
 602         power_kobj = kobject_create_and_add("power", NULL);
 603         if (!power_kobj)
 604                 return -ENOMEM;
 605         return sysfs_create_group(power_kobj, &attr_group);
 606 }
 607
 608 core_initcall(pm_init);
 609
 610
 611 #ifdef CONFIG_PM_TEST_SUSPEND
 612
 613 #include <linux/rtc.h>
 614
 615 /*
 616  * To test system suspend, we need a hands-off mechanism to resume the
 617  * system.  RTCs wake alarms are a common self-contained mechanism.
 618  */
 619
 620 static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state)
 621 {
 622         static char err_readtime[] __initdata =
 623                 KERN_ERR "PM: can't read %s time, err %d\n";
 624         static char err_wakealarm [] __initdata =
 625                 KERN_ERR "PM: can't set %s wakealarm, err %d\n";
 626         static char err_suspend[] __initdata =
 627                 KERN_ERR "PM: suspend test failed, error %d\n";
 628         static char info_test[] __initdata =
 629                 KERN_INFO "PM: test RTC wakeup from '%s' suspend\n";
 630
 631         unsigned long           now;
 632         struct rtc_wkalrm       alm;
 633         int                     status;
 634
 635         /* this may fail if the RTC hasn't been initialized */
 636         status = rtc_read_time(rtc, &alm.time);
 637         if (status < 0) {
 638                 printk(err_readtime, dev_name(&rtc->dev), status);
 639                 return;
 640         }
 641         rtc_tm_to_time(&alm.time, &now);
 642
 643         memset(&alm, 0, sizeof alm);
 644         rtc_time_to_tm(now + TEST_SUSPEND_SECONDS, &alm.time);
 645         alm.enabled = true;
 646
 647         status = rtc_set_alarm(rtc, &alm);
 648         if (status < 0) {
 649                 printk(err_wakealarm, dev_name(&rtc->dev), status);
 650                 return;
 651         }
 652
 653         if (state == PM_SUSPEND_MEM) {
 654                 printk(info_test, pm_states[state]);
 655                 status = pm_suspend(state);
 656                 if (status == -ENODEV)
 657                         state = PM_SUSPEND_STANDBY;
 658         }
 659         if (state == PM_SUSPEND_STANDBY) {
 660                 printk(info_test, pm_states[state]);
 661                 status = pm_suspend(state);
 662         }
 663         if (status < 0)
 664                 printk(err_suspend, status);
 665
 666         /* Some platforms can't detect that the alarm triggered the
 667          * wakeup, or (accordingly) disable it after it afterwards.
 668          * It's supposed to give oneshot behavior; cope.
 669          */
 670         alm.enabled = false;
 671         rtc_set_alarm(rtc, &alm);
 672 }
 673
 674 static int __init has_wakealarm(struct device *dev, void *name_ptr)
 675 {
 676         struct rtc_device *candidate = to_rtc_device(dev);
 677
 678         if (!candidate->ops->set_alarm)
 679                 return 0;
 680         if (!device_may_wakeup(candidate->dev.parent))
 681                 return 0;
 682
 683         *(const char **)name_ptr = dev_name(dev);
 684         return 1;
 685 }
 686
 687 /*
 688  * Kernel options like "test_suspend=mem" force suspend/resume sanity tests
 689  * at startup time.  They're normally disabled, for faster boot and because
 690  * we can't know which states really work on this particular system.
 691  */
 692 static suspend_state_t test_state __initdata = PM_SUSPEND_ON;
 693
 694 static char warn_bad_state[] __initdata =
 695         KERN_WARNING "PM: can't test '%s' suspend state\n";
 696
 697 static int __init setup_test_suspend(char *value)
 698 {
 699         unsigned i;
 700
 701         /* "=mem" ==> "mem" */
 702         value++;
 703         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 704                 if (!pm_states[i])
 705                         continue;
 706                 if (strcmp(pm_states[i], value) != 0)
 707                         continue;
 708                 test_state = (__force suspend_state_t) i;
 709                 return 0;
 710         }
 711         printk(warn_bad_state, value);
 712         return 0;
 713 }
 714 __setup("test_suspend", setup_test_suspend);
 715
 716 static int __init test_suspend(void)
 717 {
 718         static char             warn_no_rtc[] __initdata =
 719                 KERN_WARNING "PM: no wakealarm-capable RTC driver is ready\n";
 720
 721         char                    *pony = NULL;
 722         struct rtc_device       *rtc = NULL;
 723
 724         /* PM is initialized by now; is that state testable? */
 725         if (test_state == PM_SUSPEND_ON)
 726                 goto done;
 727         if (!valid_state(test_state)) {
 728                 printk(warn_bad_state, pm_states[test_state]);
 729                 goto done;
 730         }
 731
 732         /* RTCs have initialized by now too ... can we use one? */
 733         class_find_device(rtc_class, NULL, &pony, has_wakealarm);
 734         if (pony)
 735                 rtc = rtc_class_open(pony);
 736         if (!rtc) {
 737                 printk(warn_no_rtc);
 738                 goto done;
 739         }
 740
 741         /* go for it */
 742         test_wakealarm(rtc, test_state);
 743         rtc_class_close(rtc);
 744 done:
 745         return 0;
 746 }
 747 late_initcall(test_suspend);
 748
 749 #endif /* CONFIG_PM_TEST_SUSPEND */