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