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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 int suspend_test(int level)
  61 {
  62         if (pm_test_level == level) {
  63                 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
  64                 mdelay(5000);
  65                 return 1;
  66         }
  67         return 0;
  68 }
  69
  70 static const char * const pm_tests[__TEST_AFTER_LAST] = {
  71         [TEST_NONE] = "none",
  72         [TEST_CORE] = "core",
  73         [TEST_CPUS] = "processors",
  74         [TEST_PLATFORM] = "platform",
  75         [TEST_DEVICES] = "devices",
  76         [TEST_FREEZER] = "freezer",
  77 };
  78
  79 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
  80                                 char *buf)
  81 {
  82         char *s = buf;
  83         int level;
  84
  85         for (level = TEST_FIRST; level <= TEST_MAX; level++)
  86                 if (pm_tests[level]) {
  87                         if (level == pm_test_level)
  88                                 s += sprintf(s, "[%s] ", pm_tests[level]);
  89                         else
  90                                 s += sprintf(s, "%s ", pm_tests[level]);
  91                 }
  92
  93         if (s != buf)
  94                 /* convert the last space to a newline */
  95                 *(s-1) = '\n';
  96
  97         return (s - buf);
  98 }
  99
 100 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
 101                                 const char *buf, size_t n)
 102 {
 103         const char * const *s;
 104         int level;
 105         char *p;
 106         int len;
 107         int error = -EINVAL;
 108
 109         p = memchr(buf, '\n', n);
 110         len = p ? p - buf : n;
 111
 112         mutex_lock(&pm_mutex);
 113
 114         level = TEST_FIRST;
 115         for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
 116                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
 117                         pm_test_level = level;
 118                         error = 0;
 119                         break;
 120                 }
 121
 122         mutex_unlock(&pm_mutex);
 123
 124         return error ? error : n;
 125 }
 126
 127 power_attr(pm_test);
 128 #else /* !CONFIG_PM_DEBUG */
 129 static inline int suspend_test(int level) { return 0; }
 130 #endif /* !CONFIG_PM_DEBUG */
 131
 132 #endif /* CONFIG_PM_SLEEP */
 133
 134 #ifdef CONFIG_SUSPEND
 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 = 0;
 291
 292         device_pm_lock();
 293         arch_suspend_disable_irqs();
 294         BUG_ON(!irqs_disabled());
 295
 296         if ((error = device_power_down(PMSG_SUSPEND))) {
 297                 printk(KERN_ERR "PM: Some devices failed to power down\n");
 298                 goto Done;
 299         }
 300
 301         if (!suspend_test(TEST_CORE))
 302                 error = suspend_ops->enter(state);
 303
 304         device_power_up(PMSG_RESUME);
 305  Done:
 306         arch_suspend_enable_irqs();
 307         BUG_ON(irqs_disabled());
 308         device_pm_unlock();
 309         return error;
 310 }
 311
 312 /**
 313  *      suspend_devices_and_enter - suspend devices and enter the desired system
 314  *                                  sleep state.
 315  *      @state:           state to enter
 316  */
 317 int suspend_devices_and_enter(suspend_state_t state)
 318 {
 319         int error;
 320
 321         if (!suspend_ops)
 322                 return -ENOSYS;
 323
 324         if (suspend_ops->begin) {
 325                 error = suspend_ops->begin(state);
 326                 if (error)
 327                         goto Close;
 328         }
 329         suspend_console();
 330         suspend_test_start();
 331         error = device_suspend(PMSG_SUSPEND);
 332         if (error) {
 333                 printk(KERN_ERR "PM: Some devices failed to suspend\n");
 334                 goto Recover_platform;
 335         }
 336         suspend_test_finish("suspend devices");
 337         if (suspend_test(TEST_DEVICES))
 338                 goto Recover_platform;
 339
 340         if (suspend_ops->prepare) {
 341                 error = suspend_ops->prepare();
 342                 if (error)
 343                         goto Resume_devices;
 344         }
 345
 346         if (suspend_test(TEST_PLATFORM))
 347                 goto Finish;
 348
 349         error = disable_nonboot_cpus();
 350         if (!error && !suspend_test(TEST_CPUS))
 351                 suspend_enter(state);
 352
 353         enable_nonboot_cpus();
 354  Finish:
 355         if (suspend_ops->finish)
 356                 suspend_ops->finish();
 357  Resume_devices:
 358         suspend_test_start();
 359         device_resume(PMSG_RESUME);
 360         suspend_test_finish("resume devices");
 361         resume_console();
 362  Close:
 363         if (suspend_ops->end)
 364                 suspend_ops->end();
 365         return error;
 366
 367  Recover_platform:
 368         if (suspend_ops->recover)
 369                 suspend_ops->recover();
 370         goto Resume_devices;
 371 }
 372
 373 /**
 374  *      suspend_finish - Do final work before exiting suspend sequence.
 375  *
 376  *      Call platform code to clean up, restart processes, and free the
 377  *      console that we've allocated. This is not called for suspend-to-disk.
 378  */
 379 static void suspend_finish(void)
 380 {
 381         suspend_thaw_processes();
 382         usermodehelper_enable();
 383         pm_notifier_call_chain(PM_POST_SUSPEND);
 384         pm_restore_console();
 385 }
 386
 387
 388
 389
 390 static const char * const pm_states[PM_SUSPEND_MAX] = {
 391         [PM_SUSPEND_STANDBY]    = "standby",
 392         [PM_SUSPEND_MEM]        = "mem",
 393 };
 394
 395 static inline int valid_state(suspend_state_t state)
 396 {
 397         /* All states need lowlevel support and need to be valid
 398          * to the lowlevel implementation, no valid callback
 399          * implies that none are valid. */
 400         if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
 401                 return 0;
 402         return 1;
 403 }
 404
 405
 406 /**
 407  *      enter_state - Do common work of entering low-power state.
 408  *      @state:         pm_state structure for state we're entering.
 409  *
 410  *      Make sure we're the only ones trying to enter a sleep state. Fail
 411  *      if someone has beat us to it, since we don't want anything weird to
 412  *      happen when we wake up.
 413  *      Then, do the setup for suspend, enter the state, and cleaup (after
 414  *      we've woken up).
 415  */
 416 static int enter_state(suspend_state_t state)
 417 {
 418         int error;
 419
 420         if (!valid_state(state))
 421                 return -ENODEV;
 422
 423         if (!mutex_trylock(&pm_mutex))
 424                 return -EBUSY;
 425
 426         printk(KERN_INFO "PM: Syncing filesystems ... ");
 427         sys_sync();
 428         printk("done.\n");
 429
 430         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 431         error = suspend_prepare();
 432         if (error)
 433                 goto Unlock;
 434
 435         if (suspend_test(TEST_FREEZER))
 436                 goto Finish;
 437
 438         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
 439         error = suspend_devices_and_enter(state);
 440
 441  Finish:
 442         pr_debug("PM: Finishing wakeup.\n");
 443         suspend_finish();
 444  Unlock:
 445         mutex_unlock(&pm_mutex);
 446         return error;
 447 }
 448
 449
 450 /**
 451  *      pm_suspend - Externally visible function for suspending system.
 452  *      @state:         Enumerated value of state to enter.
 453  *
 454  *      Determine whether or not value is within range, get state
 455  *      structure, and enter (above).
 456  */
 457
 458 int pm_suspend(suspend_state_t state)
 459 {
 460         if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
 461                 return enter_state(state);
 462         return -EINVAL;
 463 }
 464
 465 EXPORT_SYMBOL(pm_suspend);
 466
 467 #endif /* CONFIG_SUSPEND */
 468
 469 struct kobject *power_kobj;
 470
 471 /**
 472  *      state - control system power state.
 473  *
 474  *      show() returns what states are supported, which is hard-coded to
 475  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 476  *      'disk' (Suspend-to-Disk).
 477  *
 478  *      store() accepts one of those strings, translates it into the
 479  *      proper enumerated value, and initiates a suspend transition.
 480  */
 481
 482 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
 483                           char *buf)
 484 {
 485         char *s = buf;
 486 #ifdef CONFIG_SUSPEND
 487         int i;
 488
 489         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 490                 if (pm_states[i] && valid_state(i))
 491                         s += sprintf(s,"%s ", pm_states[i]);
 492         }
 493 #endif
 494 #ifdef CONFIG_HIBERNATION
 495         s += sprintf(s, "%s\n", "disk");
 496 #else
 497         if (s != buf)
 498                 /* convert the last space to a newline */
 499                 *(s-1) = '\n';
 500 #endif
 501         return (s - buf);
 502 }
 503
 504 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
 505                            const char *buf, size_t n)
 506 {
 507 #ifdef CONFIG_SUSPEND
 508         suspend_state_t state = PM_SUSPEND_STANDBY;
 509         const char * const *s;
 510 #endif
 511         char *p;
 512         int len;
 513         int error = -EINVAL;
 514
 515         p = memchr(buf, '\n', n);
 516         len = p ? p - buf : n;
 517
 518         /* First, check if we are requested to hibernate */
 519         if (len == 4 && !strncmp(buf, "disk", len)) {
 520                 error = hibernate();
 521   goto Exit;
 522         }
 523
 524 #ifdef CONFIG_SUSPEND
 525         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 526                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
 527                         break;
 528         }
 529         if (state < PM_SUSPEND_MAX && *s)
 530                 error = enter_state(state);
 531 #endif
 532
 533  Exit:
 534         return error ? error : n;
 535 }
 536
 537 power_attr(state);
 538
 539 #ifdef CONFIG_PM_TRACE
 540 int pm_trace_enabled;
 541
 542 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
 543                              char *buf)
 544 {
 545         return sprintf(buf, "%d\n", pm_trace_enabled);
 546 }
 547
 548 static ssize_t
 549 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
 550                const char *buf, size_t n)
 551 {
 552         int val;
 553
 554         if (sscanf(buf, "%d", &val) == 1) {
 555                 pm_trace_enabled = !!val;
 556                 return n;
 557         }
 558         return -EINVAL;
 559 }
 560
 561 power_attr(pm_trace);
 562 #endif /* CONFIG_PM_TRACE */
 563
 564 static struct attribute * g[] = {
 565         &state_attr.attr,
 566 #ifdef CONFIG_PM_TRACE
 567         &pm_trace_attr.attr,
 568 #endif
 569 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)
 570         &pm_test_attr.attr,
 571 #endif
 572         NULL,
 573 };
 574
 575 static struct attribute_group attr_group = {
 576         .attrs = g,
 577 };
 578
 579
 580 static int __init pm_init(void)
 581 {
 582         power_kobj = kobject_create_and_add("power", NULL);
 583         if (!power_kobj)
 584                 return -ENOMEM;
 585         return sysfs_create_group(power_kobj, &attr_group);
 586 }
 587
 588 core_initcall(pm_init);
 589
 590
 591 #ifdef CONFIG_PM_TEST_SUSPEND
 592
 593 #include <linux/rtc.h>
 594
 595 /*
 596  * To test system suspend, we need a hands-off mechanism to resume the
 597  * system.  RTCs wake alarms are a common self-contained mechanism.
 598  */
 599
 600 static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state)
 601 {
 602         static char err_readtime[] __initdata =
 603                 KERN_ERR "PM: can't read %s time, err %d\n";
 604         static char err_wakealarm [] __initdata =
 605                 KERN_ERR "PM: can't set %s wakealarm, err %d\n";
 606         static char err_suspend[] __initdata =
 607                 KERN_ERR "PM: suspend test failed, error %d\n";
 608         static char info_test[] __initdata =
 609                 KERN_INFO "PM: test RTC wakeup from '%s' suspend\n";
 610
 611         unsigned long           now;
 612         struct rtc_wkalrm       alm;
 613         int                     status;
 614
 615         /* this may fail if the RTC hasn't been initialized */
 616         status = rtc_read_time(rtc, &alm.time);
 617         if (status < 0) {
 618                 printk(err_readtime, rtc->dev.bus_id, status);
 619                 return;
 620         }
 621         rtc_tm_to_time(&alm.time, &now);
 622
 623         memset(&alm, 0, sizeof alm);
 624         rtc_time_to_tm(now + TEST_SUSPEND_SECONDS, &alm.time);
 625         alm.enabled = true;
 626
 627         status = rtc_set_alarm(rtc, &alm);
 628         if (status < 0) {
 629                 printk(err_wakealarm, rtc->dev.bus_id, status);
 630                 return;
 631         }
 632
 633         if (state == PM_SUSPEND_MEM) {
 634                 printk(info_test, pm_states[state]);
 635                 status = pm_suspend(state);
 636                 if (status == -ENODEV)
 637                         state = PM_SUSPEND_STANDBY;
 638         }
 639         if (state == PM_SUSPEND_STANDBY) {
 640                 printk(info_test, pm_states[state]);
 641                 status = pm_suspend(state);
 642         }
 643         if (status < 0)
 644                 printk(err_suspend, status);
 645
 646         /* Some platforms can't detect that the alarm triggered the
 647          * wakeup, or (accordingly) disable it after it afterwards.
 648          * It's supposed to give oneshot behavior; cope.
 649          */
 650         alm.enabled = false;
 651         rtc_set_alarm(rtc, &alm);
 652 }
 653
 654 static int __init has_wakealarm(struct device *dev, void *name_ptr)
 655 {
 656         struct rtc_device *candidate = to_rtc_device(dev);
 657
 658         if (!candidate->ops->set_alarm)
 659                 return 0;
 660         if (!device_may_wakeup(candidate->dev.parent))
 661                 return 0;
 662
 663         *(char **)name_ptr = dev->bus_id;
 664         return 1;
 665 }
 666
 667 /*
 668  * Kernel options like "test_suspend=mem" force suspend/resume sanity tests
 669  * at startup time.  They're normally disabled, for faster boot and because
 670  * we can't know which states really work on this particular system.
 671  */
 672 static suspend_state_t test_state __initdata = PM_SUSPEND_ON;
 673
 674 static char warn_bad_state[] __initdata =
 675         KERN_WARNING "PM: can't test '%s' suspend state\n";
 676
 677 static int __init setup_test_suspend(char *value)
 678 {
 679         unsigned i;
 680
 681         /* "=mem" ==> "mem" */
 682         value++;
 683         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 684                 if (!pm_states[i])
 685                         continue;
 686                 if (strcmp(pm_states[i], value) != 0)
 687                         continue;
 688                 test_state = (__force suspend_state_t) i;
 689                 return 0;
 690         }
 691         printk(warn_bad_state, value);
 692         return 0;
 693 }
 694 __setup("test_suspend", setup_test_suspend);
 695
 696 static int __init test_suspend(void)
 697 {
 698         static char             warn_no_rtc[] __initdata =
 699                 KERN_WARNING "PM: no wakealarm-capable RTC driver is ready\n";
 700
 701         char                    *pony = NULL;
 702         struct rtc_device       *rtc = NULL;
 703
 704         /* PM is initialized by now; is that state testable? */
 705         if (test_state == PM_SUSPEND_ON)
 706                 goto done;
 707         if (!valid_state(test_state)) {
 708                 printk(warn_bad_state, pm_states[test_state]);
 709                 goto done;
 710         }
 711
 712         /* RTCs have initialized by now too ... can we use one? */
 713         class_find_device(rtc_class, NULL, &pony, has_wakealarm);
 714         if (pony)
 715                 rtc = rtc_class_open(pony);
 716         if (!rtc) {
 717                 printk(warn_no_rtc);
 718                 goto done;
 719         }
 720
 721         /* go for it */
 722         test_wakealarm(rtc, test_state);
 723         rtc_class_close(rtc);
 724 done:
 725         return 0;
 726 }
 727 late_initcall(test_suspend);
 728
 729 #endif /* CONFIG_PM_TEST_SUSPEND */