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   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 static struct platform_suspend_ops *suspend_ops;
 192
 193 /**
 194  *      suspend_set_ops - Set the global suspend method table.
 195  *      @ops:   Pointer to ops structure.
 196  */
 197
 198 void suspend_set_ops(struct platform_suspend_ops *ops)
 199 {
 200         mutex_lock(&pm_mutex);
 201         suspend_ops = ops;
 202         mutex_unlock(&pm_mutex);
 203 }
 204
 205 /**
 206  * suspend_valid_only_mem - generic memory-only valid callback
 207  *
 208  * Platform drivers that implement mem suspend only and only need
 209  * to check for that in their .valid callback can use this instead
 210  * of rolling their own .valid callback.
 211  */
 212 int suspend_valid_only_mem(suspend_state_t state)
 213 {
 214         return state == PM_SUSPEND_MEM;
 215 }
 216
 217 /**
 218  *      suspend_prepare - Do prep work before entering low-power state.
 219  *
 220  *      This is common code that is called for each state that we're entering.
 221  *      Run suspend notifiers, allocate a console and stop all processes.
 222  */
 223 static int suspend_prepare(void)
 224 {
 225         int error;
 226
 227         if (!suspend_ops || !suspend_ops->enter)
 228                 return -EPERM;
 229
 230         pm_prepare_console();
 231
 232         error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
 233         if (error)
 234                 goto Finish;
 235
 236         error = usermodehelper_disable();
 237         if (error)
 238                 goto Finish;
 239
 240         error = suspend_freeze_processes();
 241         if (!error)
 242                 return 0;
 243
 244         suspend_thaw_processes();
 245         usermodehelper_enable();
 246  Finish:
 247         pm_notifier_call_chain(PM_POST_SUSPEND);
 248         pm_restore_console();
 249         return error;
 250 }
 251
 252 /* default implementation */
 253 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
 254 {
 255         local_irq_disable();
 256 }
 257
 258 /* default implementation */
 259 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
 260 {
 261         local_irq_enable();
 262 }
 263
 264 /**
 265  *      suspend_enter - enter the desired system sleep state.
 266  *      @state:         state to enter
 267  *
 268  *      This function should be called after devices have been suspended.
 269  */
 270 static int suspend_enter(suspend_state_t state)
 271 {
 272         int error;
 273
 274         if (suspend_ops->prepare) {
 275                 error = suspend_ops->prepare();
 276                 if (error)
 277                         return error;
 278         }
 279
 280         error = dpm_suspend_noirq(PMSG_SUSPEND);
 281         if (error) {
 282                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 283                 goto Platfrom_finish;
 284         }
 285
 286         if (suspend_ops->prepare_late) {
 287                 error = suspend_ops->prepare_late();
 288                 if (error)
 289                         goto Power_up_devices;
 290         }
 291
 292         if (suspend_test(TEST_PLATFORM))
 293                 goto Platform_wake;
 294
 295         error = disable_nonboot_cpus();
 296         if (error || suspend_test(TEST_CPUS))
 297                 goto Enable_cpus;
 298
 299         arch_suspend_disable_irqs();
 300         BUG_ON(!irqs_disabled());
 301
 302         error = sysdev_suspend(PMSG_SUSPEND);
 303         if (!error) {
 304                 if (!suspend_test(TEST_CORE))
 305                         error = suspend_ops->enter(state);
 306                 sysdev_resume();
 307         }
 308
 309         arch_suspend_enable_irqs();
 310         BUG_ON(irqs_disabled());
 311
 312  Enable_cpus:
 313         enable_nonboot_cpus();
 314
 315  Platform_wake:
 316         if (suspend_ops->wake)
 317                 suspend_ops->wake();
 318
 319  Power_up_devices:
 320         dpm_resume_noirq(PMSG_RESUME);
 321
 322  Platfrom_finish:
 323         if (suspend_ops->finish)
 324                 suspend_ops->finish();
 325
 326         return error;
 327 }
 328
 329 /**
 330  *      suspend_devices_and_enter - suspend devices and enter the desired system
 331  *                                  sleep state.
 332  *      @state:           state to enter
 333  */
 334 int suspend_devices_and_enter(suspend_state_t state)
 335 {
 336         int error;
 337
 338         if (!suspend_ops)
 339                 return -ENOSYS;
 340
 341         if (suspend_ops->begin) {
 342                 error = suspend_ops->begin(state);
 343                 if (error)
 344                         goto Close;
 345         }
 346         suspend_console();
 347         suspend_test_start();
 348         error = dpm_suspend_start(PMSG_SUSPEND);
 349         if (error) {
 350                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 351                 goto Recover_platform;
 352         }
 353         suspend_test_finish("suspend devices");
 354         if (suspend_test(TEST_DEVICES))
 355                 goto Recover_platform;
 356
 357         suspend_enter(state);
 358
 359  Resume_devices:
 360         suspend_test_start();
 361         dpm_resume_end(PMSG_RESUME);
 362         suspend_test_finish("resume devices");
 363         resume_console();
 364  Close:
 365         if (suspend_ops->end)
 366                 suspend_ops->end();
 367         return error;
 368
 369  Recover_platform:
 370         if (suspend_ops->recover)
 371                 suspend_ops->recover();
 372         goto Resume_devices;
 373 }
 374
 375 /**
 376  *      suspend_finish - Do final work before exiting suspend sequence.
 377  *
 378  *      Call platform code to clean up, restart processes, and free the
 379  *      console that we've allocated. This is not called for suspend-to-disk.
 380  */
 381 static void suspend_finish(void)
 382 {
 383         suspend_thaw_processes();
 384         usermodehelper_enable();
 385         pm_notifier_call_chain(PM_POST_SUSPEND);
 386         pm_restore_console();
 387 }
 388
 389
 390
 391
 392 static const char * const pm_states[PM_SUSPEND_MAX] = {
 393         [PM_SUSPEND_STANDBY]    = "standby",
 394         [PM_SUSPEND_MEM]        = "mem",
 395 };
 396
 397 static inline int valid_state(suspend_state_t state)
 398 {
 399         /* All states need lowlevel support and need to be valid
 400          * to the lowlevel implementation, no valid callback
 401          * implies that none are valid. */
 402         if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
 403                 return 0;
 404         return 1;
 405 }
 406
 407
 408 /**
 409  *      enter_state - Do common work of entering low-power state.
 410  *      @state:         pm_state structure for state we're entering.
 411  *
 412  *      Make sure we're the only ones trying to enter a sleep state. Fail
 413  *      if someone has beat us to it, since we don't want anything weird to
 414  *      happen when we wake up.
 415  *      Then, do the setup for suspend, enter the state, and cleaup (after
 416  *      we've woken up).
 417  */
 418 static int enter_state(suspend_state_t state)
 419 {
 420         int error;
 421
 422         if (!valid_state(state))
 423                 return -ENODEV;
 424
 425         if (!mutex_trylock(&pm_mutex))
 426                 return -EBUSY;
 427
 428         printk(KERN_INFO "PM: Syncing filesystems ... ");
 429         sys_sync();
 430         printk("done.\n");
 431
 432         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 433         error = suspend_prepare();
 434         if (error)
 435                 goto Unlock;
 436
 437         if (suspend_test(TEST_FREEZER))
 438                 goto Finish;
 439
 440         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 441         error = suspend_devices_and_enter(state);
 442
 443  Finish:
 444         pr_debug("PM: Finishing wakeup.\n");
 445         suspend_finish();
 446  Unlock:
 447         mutex_unlock(&pm_mutex);
 448         return error;
 449 }
 450
 451
 452 /**
 453  *      pm_suspend - Externally visible function for suspending system.
 454  *      @state:         Enumerated value of state to enter.
 455  *
 456  *      Determine whether or not value is within range, get state
 457  *      structure, and enter (above).
 458  */
 459
 460 int pm_suspend(suspend_state_t state)
 461 {
 462         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 463                 return enter_state(state);
 464         return -EINVAL;
 465 }
 466
 467 EXPORT_SYMBOL(pm_suspend);
 468
 469 #endif /* CONFIG_SUSPEND */
 470
 471 struct kobject *power_kobj;
 472
 473 /**
 474  *      state - control system power state.
 475  *
 476  *      show() returns what states are supported, which is hard-coded to
 477  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 478  *      'disk' (Suspend-to-Disk).
 479  *
 480  *      store() accepts one of those strings, translates it into the
 481  *      proper enumerated value, and initiates a suspend transition.
 482  */
 483
 484 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
 485                           char *buf)
 486 {
 487         char *s = buf;
 488 #ifdef CONFIG_SUSPEND
 489         int i;
 490
 491         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 492                 if (pm_states[i] && valid_state(i))
 493                         s += sprintf(s,"%s ", pm_states[i]);
 494         }
 495 #endif
 496 #ifdef CONFIG_HIBERNATION
 497         s += sprintf(s, "%s\n", "disk");
 498 #else
 499         if (s != buf)
 500                 /* convert the last space to a newline */
 501                 *(s-1) = '\n';
 502 #endif
 503         return (s - buf);
 504 }
 505
 506 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
 507                            const char *buf, size_t n)
 508 {
 509 #ifdef CONFIG_SUSPEND
 510         suspend_state_t state = PM_SUSPEND_STANDBY;
 511         const char * const *s;
 512 #endif
 513         char *p;
 514         int len;
 515         int error = -EINVAL;
 516
 517         p = memchr(buf, '\n', n);
 518         len = p ? p - buf : n;
 519
 520         /* First, check if we are requested to hibernate */
 521         if (len == 4 && !strncmp(buf, "disk", len)) {
 522                 error = hibernate();
 523   goto Exit;
 524         }
 525
 526 #ifdef CONFIG_SUSPEND
 527         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 528                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
 529                         break;
 530         }
 531         if (state < PM_SUSPEND_MAX && *s)
 532                 error = enter_state(state);
 533 #endif
 534
 535  Exit:
 536         return error ? error : n;
 537 }
 538
 539 power_attr(state);
 540
 541 #ifdef CONFIG_PM_TRACE
 542 int pm_trace_enabled;
 543
 544 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
 545                              char *buf)
 546 {
 547         return sprintf(buf, "%d\n", pm_trace_enabled);
 548 }
 549
 550 static ssize_t
 551 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
 552                const char *buf, size_t n)
 553 {
 554         int val;
 555
 556         if (sscanf(buf, "%d", &val) == 1) {
 557                 pm_trace_enabled = !!val;
 558                 return n;
 559         }
 560         return -EINVAL;
 561 }
 562
 563 power_attr(pm_trace);
 564 #endif /* CONFIG_PM_TRACE */
 565
 566 static struct attribute * g[] = {
 567         &state_attr.attr,
 568 #ifdef CONFIG_PM_TRACE
 569         &pm_trace_attr.attr,
 570 #endif
 571 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)
 572         &pm_test_attr.attr,
 573 #endif
 574         NULL,
 575 };
 576
 577 static struct attribute_group attr_group = {
 578         .attrs = g,
 579 };
 580
 581
 582 static int __init pm_init(void)
 583 {
 584         power_kobj = kobject_create_and_add("power", NULL);
 585         if (!power_kobj)
 586                 return -ENOMEM;
 587         return sysfs_create_group(power_kobj, &attr_group);
 588 }
 589
 590 core_initcall(pm_init);
 591
 592
 593 #ifdef CONFIG_PM_TEST_SUSPEND
 594
 595 #include <linux/rtc.h>
 596
 597 /*
 598  * To test system suspend, we need a hands-off mechanism to resume the
 599  * system.  RTCs wake alarms are a common self-contained mechanism.
 600  */
 601
 602 static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state)
 603 {
 604         static char err_readtime[] __initdata =
 605                 KERN_ERR "PM: can't read %s time, err %d\n";
 606         static char err_wakealarm [] __initdata =
 607                 KERN_ERR "PM: can't set %s wakealarm, err %d\n";
 608         static char err_suspend[] __initdata =
 609                 KERN_ERR "PM: suspend test failed, error %d\n";
 610         static char info_test[] __initdata =
 611                 KERN_INFO "PM: test RTC wakeup from '%s' suspend\n";
 612
 613         unsigned long           now;
 614         struct rtc_wkalrm       alm;
 615         int                     status;
 616
 617         /* this may fail if the RTC hasn't been initialized */
 618         status = rtc_read_time(rtc, &alm.time);
 619         if (status < 0) {
 620                 printk(err_readtime, dev_name(&rtc->dev), status);
 621                 return;
 622         }
 623         rtc_tm_to_time(&alm.time, &now);
 624
 625         memset(&alm, 0, sizeof alm);
 626         rtc_time_to_tm(now + TEST_SUSPEND_SECONDS, &alm.time);
 627         alm.enabled = true;
 628
 629         status = rtc_set_alarm(rtc, &alm);
 630         if (status < 0) {
 631                 printk(err_wakealarm, dev_name(&rtc->dev), status);
 632                 return;
 633         }
 634
 635         if (state == PM_SUSPEND_MEM) {
 636                 printk(info_test, pm_states[state]);
 637                 status = pm_suspend(state);
 638                 if (status == -ENODEV)
 639                         state = PM_SUSPEND_STANDBY;
 640         }
 641         if (state == PM_SUSPEND_STANDBY) {
 642                 printk(info_test, pm_states[state]);
 643                 status = pm_suspend(state);
 644         }
 645         if (status < 0)
 646                 printk(err_suspend, status);
 647
 648         /* Some platforms can't detect that the alarm triggered the
 649          * wakeup, or (accordingly) disable it after it afterwards.
 650          * It's supposed to give oneshot behavior; cope.
 651          */
 652         alm.enabled = false;
 653         rtc_set_alarm(rtc, &alm);
 654 }
 655
 656 static int __init has_wakealarm(struct device *dev, void *name_ptr)
 657 {
 658         struct rtc_device *candidate = to_rtc_device(dev);
 659
 660         if (!candidate->ops->set_alarm)
 661                 return 0;
 662         if (!device_may_wakeup(candidate->dev.parent))
 663                 return 0;
 664
 665         *(const char **)name_ptr = dev_name(dev);
 666         return 1;
 667 }
 668
 669 /*
 670  * Kernel options like "test_suspend=mem" force suspend/resume sanity tests
 671  * at startup time.  They're normally disabled, for faster boot and because
 672  * we can't know which states really work on this particular system.
 673  */
 674 static suspend_state_t test_state __initdata = PM_SUSPEND_ON;
 675
 676 static char warn_bad_state[] __initdata =
 677         KERN_WARNING "PM: can't test '%s' suspend state\n";
 678
 679 static int __init setup_test_suspend(char *value)
 680 {
 681         unsigned i;
 682
 683         /* "=mem" ==> "mem" */
 684         value++;
 685         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 686                 if (!pm_states[i])
 687                         continue;
 688                 if (strcmp(pm_states[i], value) != 0)
 689                         continue;
 690                 test_state = (__force suspend_state_t) i;
 691                 return 0;
 692         }
 693         printk(warn_bad_state, value);
 694         return 0;
 695 }
 696 __setup("test_suspend", setup_test_suspend);
 697
 698 static int __init test_suspend(void)
 699 {
 700         static char             warn_no_rtc[] __initdata =
 701                 KERN_WARNING "PM: no wakealarm-capable RTC driver is ready\n";
 702
 703         char                    *pony = NULL;
 704         struct rtc_device       *rtc = NULL;
 705
 706         /* PM is initialized by now; is that state testable? */
 707         if (test_state == PM_SUSPEND_ON)
 708                 goto done;
 709         if (!valid_state(test_state)) {
 710                 printk(warn_bad_state, pm_states[test_state]);
 711                 goto done;
 712         }
 713
 714         /* RTCs have initialized by now too ... can we use one? */
 715         class_find_device(rtc_class, NULL, &pony, has_wakealarm);
 716         if (pony)
 717                 rtc = rtc_class_open(pony);
 718         if (!rtc) {
 719                 printk(warn_no_rtc);
 720                 goto done;
 721         }
 722
 723         /* go for it */
 724         test_wakealarm(rtc, test_state);
 725         rtc_class_close(rtc);
 726 done:
 727         return 0;
 728 }
 729 late_initcall(test_suspend);
 730
 731 #endif /* CONFIG_PM_TEST_SUSPEND */