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 */ 750