1// SPDX-License-Identifier: GPL-2.0 2/* 3 * drivers/base/power/runtime.c - Helper functions for device runtime PM 4 * 5 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc. 6 * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu> 7 */ 8#include <linux/sched/mm.h> 9#include <linux/ktime.h> 10#include <linux/hrtimer.h> 11#include <linux/export.h> 12#include <linux/pm_runtime.h> 13#include <linux/pm_wakeirq.h> 14#include <linux/rculist.h> 15#include <trace/events/rpm.h> 16 17#include "../base.h" 18#include "power.h" 19 20typedef int (*pm_callback_t)(struct device *); 21 22static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset) 23{ 24 pm_callback_t cb; 25 const struct dev_pm_ops *ops; 26 27 if (dev->pm_domain) 28 ops = &dev->pm_domain->ops; 29 else if (dev->type && dev->type->pm) 30 ops = dev->type->pm; 31 else if (dev->class && dev->class->pm) 32 ops = dev->class->pm; 33 else if (dev->bus && dev->bus->pm) 34 ops = dev->bus->pm; 35 else 36 ops = NULL; 37 38 if (ops) 39 cb = *(pm_callback_t *)((void *)ops + cb_offset); 40 else 41 cb = NULL; 42 43 if (!cb && dev->driver && dev->driver->pm) 44 cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset); 45 46 return cb; 47} 48 49#define RPM_GET_CALLBACK(dev, callback) \ 50 __rpm_get_callback(dev, offsetof(struct dev_pm_ops, callback)) 51 52static int rpm_resume(struct device *dev, int rpmflags); 53static int rpm_suspend(struct device *dev, int rpmflags); 54 55/** 56 * update_pm_runtime_accounting - Update the time accounting of power states 57 * @dev: Device to update the accounting for 58 * 59 * In order to be able to have time accounting of the various power states 60 * (as used by programs such as PowerTOP to show the effectiveness of runtime 61 * PM), we need to track the time spent in each state. 62 * update_pm_runtime_accounting must be called each time before the 63 * runtime_status field is updated, to account the time in the old state 64 * correctly. 65 */ 66static void update_pm_runtime_accounting(struct device *dev) 67{ 68 u64 now, last, delta; 69 70 if (dev->power.disable_depth > 0) 71 return; 72 73 last = dev->power.accounting_timestamp; 74 75 now = ktime_get_mono_fast_ns(); 76 dev->power.accounting_timestamp = now; 77 78 /* 79 * Because ktime_get_mono_fast_ns() is not monotonic during 80 * timekeeping updates, ensure that 'now' is after the last saved 81 * timesptamp. 82 */ 83 if (now < last) 84 return; 85 86 delta = now - last; 87 88 if (dev->power.runtime_status == RPM_SUSPENDED) 89 dev->power.suspended_time += delta; 90 else 91 dev->power.active_time += delta; 92} 93 94static void __update_runtime_status(struct device *dev, enum rpm_status status) 95{ 96 update_pm_runtime_accounting(dev); 97 trace_rpm_status(dev, status); 98 dev->power.runtime_status = status; 99} 100 101static u64 rpm_get_accounted_time(struct device *dev, bool suspended) 102{ 103 u64 time; 104 unsigned long flags; 105 106 spin_lock_irqsave(&dev->power.lock, flags); 107 108 update_pm_runtime_accounting(dev); 109 time = suspended ? dev->power.suspended_time : dev->power.active_time; 110 111 spin_unlock_irqrestore(&dev->power.lock, flags); 112 113 return time; 114} 115 116u64 pm_runtime_active_time(struct device *dev) 117{ 118 return rpm_get_accounted_time(dev, false); 119} 120 121u64 pm_runtime_suspended_time(struct device *dev) 122{ 123 return rpm_get_accounted_time(dev, true); 124} 125EXPORT_SYMBOL_GPL(pm_runtime_suspended_time); 126 127/** 128 * pm_runtime_deactivate_timer - Deactivate given device's suspend timer. 129 * @dev: Device to handle. 130 */ 131static void pm_runtime_deactivate_timer(struct device *dev) 132{ 133 if (dev->power.timer_expires > 0) { 134 hrtimer_try_to_cancel(&dev->power.suspend_timer); 135 dev->power.timer_expires = 0; 136 } 137} 138 139/** 140 * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests. 141 * @dev: Device to handle. 142 */ 143static void pm_runtime_cancel_pending(struct device *dev) 144{ 145 pm_runtime_deactivate_timer(dev); 146 /* 147 * In case there's a request pending, make sure its work function will 148 * return without doing anything. 149 */ 150 dev->power.request = RPM_REQ_NONE; 151} 152 153/* 154 * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time. 155 * @dev: Device to handle. 156 * 157 * Compute the autosuspend-delay expiration time based on the device's 158 * power.last_busy time. If the delay has already expired or is disabled 159 * (negative) or the power.use_autosuspend flag isn't set, return 0. 160 * Otherwise return the expiration time in nanoseconds (adjusted to be nonzero). 161 * 162 * This function may be called either with or without dev->power.lock held. 163 * Either way it can be racy, since power.last_busy may be updated at any time. 164 */ 165u64 pm_runtime_autosuspend_expiration(struct device *dev) 166{ 167 int autosuspend_delay; 168 u64 expires; 169 170 if (!dev->power.use_autosuspend) 171 return 0; 172 173 autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay); 174 if (autosuspend_delay < 0) 175 return 0; 176 177 expires = READ_ONCE(dev->power.last_busy); 178 expires += (u64)autosuspend_delay * NSEC_PER_MSEC; 179 if (expires > ktime_get_mono_fast_ns()) 180 return expires; /* Expires in the future */ 181 182 return 0; 183} 184EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration); 185 186static int dev_memalloc_noio(struct device *dev, void *data) 187{ 188 return dev->power.memalloc_noio; 189} 190 191/* 192 * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag. 193 * @dev: Device to handle. 194 * @enable: True for setting the flag and False for clearing the flag. 195 * 196 * Set the flag for all devices in the path from the device to the 197 * root device in the device tree if @enable is true, otherwise clear 198 * the flag for devices in the path whose siblings don't set the flag. 199 * 200 * The function should only be called by block device, or network 201 * device driver for solving the deadlock problem during runtime 202 * resume/suspend: 203 * 204 * If memory allocation with GFP_KERNEL is called inside runtime 205 * resume/suspend callback of any one of its ancestors(or the 206 * block device itself), the deadlock may be triggered inside the 207 * memory allocation since it might not complete until the block 208 * device becomes active and the involed page I/O finishes. The 209 * situation is pointed out first by Alan Stern. Network device 210 * are involved in iSCSI kind of situation. 211 * 212 * The lock of dev_hotplug_mutex is held in the function for handling 213 * hotplug race because pm_runtime_set_memalloc_noio() may be called 214 * in async probe(). 215 * 216 * The function should be called between device_add() and device_del() 217 * on the affected device(block/network device). 218 */ 219void pm_runtime_set_memalloc_noio(struct device *dev, bool enable) 220{ 221 static DEFINE_MUTEX(dev_hotplug_mutex); 222 223 mutex_lock(&dev_hotplug_mutex); 224 for (;;) { 225 bool enabled; 226 227 /* hold power lock since bitfield is not SMP-safe. */ 228 spin_lock_irq(&dev->power.lock); 229 enabled = dev->power.memalloc_noio; 230 dev->power.memalloc_noio = enable; 231 spin_unlock_irq(&dev->power.lock); 232 233 /* 234 * not need to enable ancestors any more if the device 235 * has been enabled. 236 */ 237 if (enabled && enable) 238 break; 239 240 dev = dev->parent; 241 242 /* 243 * clear flag of the parent device only if all the 244 * children don't set the flag because ancestor's 245 * flag was set by any one of the descendants. 246 */ 247 if (!dev || (!enable && 248 device_for_each_child(dev, NULL, dev_memalloc_noio))) 249 break; 250 } 251 mutex_unlock(&dev_hotplug_mutex); 252} 253EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio); 254 255/** 256 * rpm_check_suspend_allowed - Test whether a device may be suspended. 257 * @dev: Device to test. 258 */ 259static int rpm_check_suspend_allowed(struct device *dev) 260{ 261 int retval = 0; 262 263 if (dev->power.runtime_error) 264 retval = -EINVAL; 265 else if (dev->power.disable_depth > 0) 266 retval = -EACCES; 267 else if (atomic_read(&dev->power.usage_count)) 268 retval = -EAGAIN; 269 else if (!dev->power.ignore_children && atomic_read(&dev->power.child_count)) 270 retval = -EBUSY; 271 272 /* Pending resume requests take precedence over suspends. */ 273 else if ((dev->power.deferred_resume && 274 dev->power.runtime_status == RPM_SUSPENDING) || 275 (dev->power.request_pending && dev->power.request == RPM_REQ_RESUME)) 276 retval = -EAGAIN; 277 else if (__dev_pm_qos_resume_latency(dev) == 0) 278 retval = -EPERM; 279 else if (dev->power.runtime_status == RPM_SUSPENDED) 280 retval = 1; 281 282 return retval; 283} 284 285static int rpm_get_suppliers(struct device *dev) 286{ 287 struct device_link *link; 288 289 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node, 290 device_links_read_lock_held()) { 291 int retval; 292 293 if (!(link->flags & DL_FLAG_PM_RUNTIME)) 294 continue; 295 296 retval = pm_runtime_get_sync(link->supplier); 297 /* Ignore suppliers with disabled runtime PM. */ 298 if (retval < 0 && retval != -EACCES) { 299 pm_runtime_put_noidle(link->supplier); 300 return retval; 301 } 302 refcount_inc(&link->rpm_active); 303 } 304 return 0; 305} 306 307/** 308 * pm_runtime_release_supplier - Drop references to device link's supplier. 309 * @link: Target device link. 310 * 311 * Drop all runtime PM references associated with @link to its supplier device. 312 */ 313void pm_runtime_release_supplier(struct device_link *link) 314{ 315 struct device *supplier = link->supplier; 316 317 /* 318 * The additional power.usage_count check is a safety net in case 319 * the rpm_active refcount becomes saturated, in which case 320 * refcount_dec_not_one() would return true forever, but it is not 321 * strictly necessary. 322 */ 323 while (refcount_dec_not_one(&link->rpm_active) && 324 atomic_read(&supplier->power.usage_count) > 0) 325 pm_runtime_put_noidle(supplier); 326} 327 328static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend) 329{ 330 struct device_link *link; 331 332 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node, 333 device_links_read_lock_held()) { 334 pm_runtime_release_supplier(link); 335 if (try_to_suspend) 336 pm_request_idle(link->supplier); 337 } 338} 339 340static void rpm_put_suppliers(struct device *dev) 341{ 342 __rpm_put_suppliers(dev, true); 343} 344 345static void rpm_suspend_suppliers(struct device *dev) 346{ 347 struct device_link *link; 348 int idx = device_links_read_lock(); 349 350 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node, 351 device_links_read_lock_held()) 352 pm_request_idle(link->supplier); 353 354 device_links_read_unlock(idx); 355} 356 357/** 358 * __rpm_callback - Run a given runtime PM callback for a given device. 359 * @cb: Runtime PM callback to run. 360 * @dev: Device to run the callback for. 361 */ 362static int __rpm_callback(int (*cb)(struct device *), struct device *dev) 363 __releases(&dev->power.lock) __acquires(&dev->power.lock) 364{ 365 int retval = 0, idx; 366 bool use_links = dev->power.links_count > 0; 367 368 if (dev->power.irq_safe) { 369 spin_unlock(&dev->power.lock); 370 } else { 371 spin_unlock_irq(&dev->power.lock); 372 373 /* 374 * Resume suppliers if necessary. 375 * 376 * The device's runtime PM status cannot change until this 377 * routine returns, so it is safe to read the status outside of 378 * the lock. 379 */ 380 if (use_links && dev->power.runtime_status == RPM_RESUMING) { 381 idx = device_links_read_lock(); 382 383 retval = rpm_get_suppliers(dev); 384 if (retval) { 385 rpm_put_suppliers(dev); 386 goto fail; 387 } 388 389 device_links_read_unlock(idx); 390 } 391 } 392 393 if (cb) 394 retval = cb(dev); 395 396 if (dev->power.irq_safe) { 397 spin_lock(&dev->power.lock); 398 } else { 399 /* 400 * If the device is suspending and the callback has returned 401 * success, drop the usage counters of the suppliers that have 402 * been reference counted on its resume. 403 * 404 * Do that if resume fails too. 405 */ 406 if (use_links && 407 ((dev->power.runtime_status == RPM_SUSPENDING && !retval) || 408 (dev->power.runtime_status == RPM_RESUMING && retval))) { 409 idx = device_links_read_lock(); 410 411 __rpm_put_suppliers(dev, false); 412 413fail: 414 device_links_read_unlock(idx); 415 } 416 417 spin_lock_irq(&dev->power.lock); 418 } 419 420 return retval; 421} 422 423/** 424 * rpm_callback - Run a given runtime PM callback for a given device. 425 * @cb: Runtime PM callback to run. 426 * @dev: Device to run the callback for. 427 */ 428static int rpm_callback(int (*cb)(struct device *), struct device *dev) 429{ 430 int retval; 431 432 if (dev->power.memalloc_noio) { 433 unsigned int noio_flag; 434 435 /* 436 * Deadlock might be caused if memory allocation with 437 * GFP_KERNEL happens inside runtime_suspend and 438 * runtime_resume callbacks of one block device's 439 * ancestor or the block device itself. Network 440 * device might be thought as part of iSCSI block 441 * device, so network device and its ancestor should 442 * be marked as memalloc_noio too. 443 */ 444 noio_flag = memalloc_noio_save(); 445 retval = __rpm_callback(cb, dev); 446 memalloc_noio_restore(noio_flag); 447 } else { 448 retval = __rpm_callback(cb, dev); 449 } 450 451 dev->power.runtime_error = retval; 452 return retval != -EACCES ? retval : -EIO; 453} 454 455/** 456 * rpm_idle - Notify device bus type if the device can be suspended. 457 * @dev: Device to notify the bus type about. 458 * @rpmflags: Flag bits. 459 * 460 * Check if the device's runtime PM status allows it to be suspended. If 461 * another idle notification has been started earlier, return immediately. If 462 * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise 463 * run the ->runtime_idle() callback directly. If the ->runtime_idle callback 464 * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag. 465 * 466 * This function must be called under dev->power.lock with interrupts disabled. 467 */ 468static int rpm_idle(struct device *dev, int rpmflags) 469{ 470 int (*callback)(struct device *); 471 int retval; 472 473 trace_rpm_idle(dev, rpmflags); 474 retval = rpm_check_suspend_allowed(dev); 475 if (retval < 0) 476 ; /* Conditions are wrong. */ 477 478 /* Idle notifications are allowed only in the RPM_ACTIVE state. */ 479 else if (dev->power.runtime_status != RPM_ACTIVE) 480 retval = -EAGAIN; 481 482 /* 483 * Any pending request other than an idle notification takes 484 * precedence over us, except that the timer may be running. 485 */ 486 else if (dev->power.request_pending && 487 dev->power.request > RPM_REQ_IDLE) 488 retval = -EAGAIN; 489 490 /* Act as though RPM_NOWAIT is always set. */ 491 else if (dev->power.idle_notification) 492 retval = -EINPROGRESS; 493 494 if (retval) 495 goto out; 496 497 /* Pending requests need to be canceled. */ 498 dev->power.request = RPM_REQ_NONE; 499 500 callback = RPM_GET_CALLBACK(dev, runtime_idle); 501 502 /* If no callback assume success. */ 503 if (!callback || dev->power.no_callbacks) 504 goto out; 505 506 /* Carry out an asynchronous or a synchronous idle notification. */ 507 if (rpmflags & RPM_ASYNC) { 508 dev->power.request = RPM_REQ_IDLE; 509 if (!dev->power.request_pending) { 510 dev->power.request_pending = true; 511 queue_work(pm_wq, &dev->power.work); 512 } 513 trace_rpm_return_int(dev, _THIS_IP_, 0); 514 return 0; 515 } 516 517 dev->power.idle_notification = true; 518 519 if (dev->power.irq_safe) 520 spin_unlock(&dev->power.lock); 521 else 522 spin_unlock_irq(&dev->power.lock); 523 524 retval = callback(dev); 525 526 if (dev->power.irq_safe) 527 spin_lock(&dev->power.lock); 528 else 529 spin_lock_irq(&dev->power.lock); 530 531 dev->power.idle_notification = false; 532 wake_up_all(&dev->power.wait_queue); 533 534 out: 535 trace_rpm_return_int(dev, _THIS_IP_, retval); 536 return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO); 537} 538 539/** 540 * rpm_suspend - Carry out runtime suspend of given device. 541 * @dev: Device to suspend. 542 * @rpmflags: Flag bits. 543 * 544 * Check if the device's runtime PM status allows it to be suspended. 545 * Cancel a pending idle notification, autosuspend or suspend. If 546 * another suspend has been started earlier, either return immediately 547 * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC 548 * flags. If the RPM_ASYNC flag is set then queue a suspend request; 549 * otherwise run the ->runtime_suspend() callback directly. When 550 * ->runtime_suspend succeeded, if a deferred resume was requested while 551 * the callback was running then carry it out, otherwise send an idle 552 * notification for its parent (if the suspend succeeded and both 553 * ignore_children of parent->power and irq_safe of dev->power are not set). 554 * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO 555 * flag is set and the next autosuspend-delay expiration time is in the 556 * future, schedule another autosuspend attempt. 557 * 558 * This function must be called under dev->power.lock with interrupts disabled. 559 */ 560static int rpm_suspend(struct device *dev, int rpmflags) 561 __releases(&dev->power.lock) __acquires(&dev->power.lock) 562{ 563 int (*callback)(struct device *); 564 struct device *parent = NULL; 565 int retval; 566 567 trace_rpm_suspend(dev, rpmflags); 568 569 repeat: 570 retval = rpm_check_suspend_allowed(dev); 571 if (retval < 0) 572 goto out; /* Conditions are wrong. */ 573 574 /* Synchronous suspends are not allowed in the RPM_RESUMING state. */ 575 if (dev->power.runtime_status == RPM_RESUMING && !(rpmflags & RPM_ASYNC)) 576 retval = -EAGAIN; 577 578 if (retval) 579 goto out; 580 581 /* If the autosuspend_delay time hasn't expired yet, reschedule. */ 582 if ((rpmflags & RPM_AUTO) && dev->power.runtime_status != RPM_SUSPENDING) { 583 u64 expires = pm_runtime_autosuspend_expiration(dev); 584 585 if (expires != 0) { 586 /* Pending requests need to be canceled. */ 587 dev->power.request = RPM_REQ_NONE; 588 589 /* 590 * Optimization: If the timer is already running and is 591 * set to expire at or before the autosuspend delay, 592 * avoid the overhead of resetting it. Just let it 593 * expire; pm_suspend_timer_fn() will take care of the 594 * rest. 595 */ 596 if (!(dev->power.timer_expires && 597 dev->power.timer_expires <= expires)) { 598 /* 599 * We add a slack of 25% to gather wakeups 600 * without sacrificing the granularity. 601 */ 602 u64 slack = (u64)READ_ONCE(dev->power.autosuspend_delay) * 603 (NSEC_PER_MSEC >> 2); 604 605 dev->power.timer_expires = expires; 606 hrtimer_start_range_ns(&dev->power.suspend_timer, 607 ns_to_ktime(expires), 608 slack, 609 HRTIMER_MODE_ABS); 610 } 611 dev->power.timer_autosuspends = 1; 612 goto out; 613 } 614 } 615 616 /* Other scheduled or pending requests need to be canceled. */ 617 pm_runtime_cancel_pending(dev); 618 619 if (dev->power.runtime_status == RPM_SUSPENDING) { 620 DEFINE_WAIT(wait); 621 622 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) { 623 retval = -EINPROGRESS; 624 goto out; 625 } 626 627 if (dev->power.irq_safe) { 628 spin_unlock(&dev->power.lock); 629 630 cpu_relax(); 631 632 spin_lock(&dev->power.lock); 633 goto repeat; 634 } 635 636 /* Wait for the other suspend running in parallel with us. */ 637 for (;;) { 638 prepare_to_wait(&dev->power.wait_queue, &wait, 639 TASK_UNINTERRUPTIBLE); 640 if (dev->power.runtime_status != RPM_SUSPENDING) 641 break; 642 643 spin_unlock_irq(&dev->power.lock); 644 645 schedule(); 646 647 spin_lock_irq(&dev->power.lock); 648 } 649 finish_wait(&dev->power.wait_queue, &wait); 650 goto repeat; 651 } 652 653 if (dev->power.no_callbacks) 654 goto no_callback; /* Assume success. */ 655 656 /* Carry out an asynchronous or a synchronous suspend. */ 657 if (rpmflags & RPM_ASYNC) { 658 dev->power.request = (rpmflags & RPM_AUTO) ? 659 RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND; 660 if (!dev->power.request_pending) { 661 dev->power.request_pending = true; 662 queue_work(pm_wq, &dev->power.work); 663 } 664 goto out; 665 } 666 667 __update_runtime_status(dev, RPM_SUSPENDING); 668 669 callback = RPM_GET_CALLBACK(dev, runtime_suspend); 670 671 dev_pm_enable_wake_irq_check(dev, true); 672 retval = rpm_callback(callback, dev); 673 if (retval) 674 goto fail; 675 676 dev_pm_enable_wake_irq_complete(dev); 677 678 no_callback: 679 __update_runtime_status(dev, RPM_SUSPENDED); 680 pm_runtime_deactivate_timer(dev); 681 682 if (dev->parent) { 683 parent = dev->parent; 684 atomic_add_unless(&parent->power.child_count, -1, 0); 685 } 686 wake_up_all(&dev->power.wait_queue); 687 688 if (dev->power.deferred_resume) { 689 dev->power.deferred_resume = false; 690 rpm_resume(dev, 0); 691 retval = -EAGAIN; 692 goto out; 693 } 694 695 if (dev->power.irq_safe) 696 goto out; 697 698 /* Maybe the parent is now able to suspend. */ 699 if (parent && !parent->power.ignore_children) { 700 spin_unlock(&dev->power.lock); 701 702 spin_lock(&parent->power.lock); 703 rpm_idle(parent, RPM_ASYNC); 704 spin_unlock(&parent->power.lock); 705 706 spin_lock(&dev->power.lock); 707 } 708 /* Maybe the suppliers are now able to suspend. */ 709 if (dev->power.links_count > 0) { 710 spin_unlock_irq(&dev->power.lock); 711 712 rpm_suspend_suppliers(dev); 713 714 spin_lock_irq(&dev->power.lock); 715 } 716 717 out: 718 trace_rpm_return_int(dev, _THIS_IP_, retval); 719 720 return retval; 721 722 fail: 723 dev_pm_disable_wake_irq_check(dev, true); 724 __update_runtime_status(dev, RPM_ACTIVE); 725 dev->power.deferred_resume = false; 726 wake_up_all(&dev->power.wait_queue); 727 728 if (retval == -EAGAIN || retval == -EBUSY) { 729 dev->power.runtime_error = 0; 730 731 /* 732 * If the callback routine failed an autosuspend, and 733 * if the last_busy time has been updated so that there 734 * is a new autosuspend expiration time, automatically 735 * reschedule another autosuspend. 736 */ 737 if ((rpmflags & RPM_AUTO) && 738 pm_runtime_autosuspend_expiration(dev) != 0) 739 goto repeat; 740 } else { 741 pm_runtime_cancel_pending(dev); 742 } 743 goto out; 744} 745 746/** 747 * rpm_resume - Carry out runtime resume of given device. 748 * @dev: Device to resume. 749 * @rpmflags: Flag bits. 750 * 751 * Check if the device's runtime PM status allows it to be resumed. Cancel 752 * any scheduled or pending requests. If another resume has been started 753 * earlier, either return immediately or wait for it to finish, depending on the 754 * RPM_NOWAIT and RPM_ASYNC flags. Similarly, if there's a suspend running in 755 * parallel with this function, either tell the other process to resume after 756 * suspending (deferred_resume) or wait for it to finish. If the RPM_ASYNC 757 * flag is set then queue a resume request; otherwise run the 758 * ->runtime_resume() callback directly. Queue an idle notification for the 759 * device if the resume succeeded. 760 * 761 * This function must be called under dev->power.lock with interrupts disabled. 762 */ 763static int rpm_resume(struct device *dev, int rpmflags) 764 __releases(&dev->power.lock) __acquires(&dev->power.lock) 765{ 766 int (*callback)(struct device *); 767 struct device *parent = NULL; 768 int retval = 0; 769 770 trace_rpm_resume(dev, rpmflags); 771 772 repeat: 773 if (dev->power.runtime_error) { 774 retval = -EINVAL; 775 } else if (dev->power.disable_depth > 0) { 776 if (dev->power.runtime_status == RPM_ACTIVE && 777 dev->power.last_status == RPM_ACTIVE) 778 retval = 1; 779 else 780 retval = -EACCES; 781 } 782 if (retval) 783 goto out; 784 785 /* 786 * Other scheduled or pending requests need to be canceled. Small 787 * optimization: If an autosuspend timer is running, leave it running 788 * rather than cancelling it now only to restart it again in the near 789 * future. 790 */ 791 dev->power.request = RPM_REQ_NONE; 792 if (!dev->power.timer_autosuspends) 793 pm_runtime_deactivate_timer(dev); 794 795 if (dev->power.runtime_status == RPM_ACTIVE) { 796 retval = 1; 797 goto out; 798 } 799 800 if (dev->power.runtime_status == RPM_RESUMING || 801 dev->power.runtime_status == RPM_SUSPENDING) { 802 DEFINE_WAIT(wait); 803 804 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) { 805 if (dev->power.runtime_status == RPM_SUSPENDING) { 806 dev->power.deferred_resume = true; 807 if (rpmflags & RPM_NOWAIT) 808 retval = -EINPROGRESS; 809 } else { 810 retval = -EINPROGRESS; 811 } 812 goto out; 813 } 814 815 if (dev->power.irq_safe) { 816 spin_unlock(&dev->power.lock); 817 818 cpu_relax(); 819 820 spin_lock(&dev->power.lock); 821 goto repeat; 822 } 823 824 /* Wait for the operation carried out in parallel with us. */ 825 for (;;) { 826 prepare_to_wait(&dev->power.wait_queue, &wait, 827 TASK_UNINTERRUPTIBLE); 828 if (dev->power.runtime_status != RPM_RESUMING && 829 dev->power.runtime_status != RPM_SUSPENDING) 830 break; 831 832 spin_unlock_irq(&dev->power.lock); 833 834 schedule(); 835 836 spin_lock_irq(&dev->power.lock); 837 } 838 finish_wait(&dev->power.wait_queue, &wait); 839 goto repeat; 840 } 841 842 /* 843 * See if we can skip waking up the parent. This is safe only if 844 * power.no_callbacks is set, because otherwise we don't know whether 845 * the resume will actually succeed. 846 */ 847 if (dev->power.no_callbacks && !parent && dev->parent) { 848 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING); 849 if (dev->parent->power.disable_depth > 0 || 850 dev->parent->power.ignore_children || 851 dev->parent->power.runtime_status == RPM_ACTIVE) { 852 atomic_inc(&dev->parent->power.child_count); 853 spin_unlock(&dev->parent->power.lock); 854 retval = 1; 855 goto no_callback; /* Assume success. */ 856 } 857 spin_unlock(&dev->parent->power.lock); 858 } 859 860 /* Carry out an asynchronous or a synchronous resume. */ 861 if (rpmflags & RPM_ASYNC) { 862 dev->power.request = RPM_REQ_RESUME; 863 if (!dev->power.request_pending) { 864 dev->power.request_pending = true; 865 queue_work(pm_wq, &dev->power.work); 866 } 867 retval = 0; 868 goto out; 869 } 870 871 if (!parent && dev->parent) { 872 /* 873 * Increment the parent's usage counter and resume it if 874 * necessary. Not needed if dev is irq-safe; then the 875 * parent is permanently resumed. 876 */ 877 parent = dev->parent; 878 if (dev->power.irq_safe) 879 goto skip_parent; 880 881 spin_unlock(&dev->power.lock); 882 883 pm_runtime_get_noresume(parent); 884 885 spin_lock(&parent->power.lock); 886 /* 887 * Resume the parent if it has runtime PM enabled and not been 888 * set to ignore its children. 889 */ 890 if (!parent->power.disable_depth && 891 !parent->power.ignore_children) { 892 rpm_resume(parent, 0); 893 if (parent->power.runtime_status != RPM_ACTIVE) 894 retval = -EBUSY; 895 } 896 spin_unlock(&parent->power.lock); 897 898 spin_lock(&dev->power.lock); 899 if (retval) 900 goto out; 901 902 goto repeat; 903 } 904 skip_parent: 905 906 if (dev->power.no_callbacks) 907 goto no_callback; /* Assume success. */ 908 909 __update_runtime_status(dev, RPM_RESUMING); 910 911 callback = RPM_GET_CALLBACK(dev, runtime_resume); 912 913 dev_pm_disable_wake_irq_check(dev, false); 914 retval = rpm_callback(callback, dev); 915 if (retval) { 916 __update_runtime_status(dev, RPM_SUSPENDED); 917 pm_runtime_cancel_pending(dev); 918 dev_pm_enable_wake_irq_check(dev, false); 919 } else { 920 no_callback: 921 __update_runtime_status(dev, RPM_ACTIVE); 922 pm_runtime_mark_last_busy(dev); 923 if (parent) 924 atomic_inc(&parent->power.child_count); 925 } 926 wake_up_all(&dev->power.wait_queue); 927 928 if (retval >= 0) 929 rpm_idle(dev, RPM_ASYNC); 930 931 out: 932 if (parent && !dev->power.irq_safe) { 933 spin_unlock_irq(&dev->power.lock); 934 935 pm_runtime_put(parent); 936 937 spin_lock_irq(&dev->power.lock); 938 } 939 940 trace_rpm_return_int(dev, _THIS_IP_, retval); 941 942 return retval; 943} 944 945/** 946 * pm_runtime_work - Universal runtime PM work function. 947 * @work: Work structure used for scheduling the execution of this function. 948 * 949 * Use @work to get the device object the work is to be done for, determine what 950 * is to be done and execute the appropriate runtime PM function. 951 */ 952static void pm_runtime_work(struct work_struct *work) 953{ 954 struct device *dev = container_of(work, struct device, power.work); 955 enum rpm_request req; 956 957 spin_lock_irq(&dev->power.lock); 958 959 if (!dev->power.request_pending) 960 goto out; 961 962 req = dev->power.request; 963 dev->power.request = RPM_REQ_NONE; 964 dev->power.request_pending = false; 965 966 switch (req) { 967 case RPM_REQ_NONE: 968 break; 969 case RPM_REQ_IDLE: 970 rpm_idle(dev, RPM_NOWAIT); 971 break; 972 case RPM_REQ_SUSPEND: 973 rpm_suspend(dev, RPM_NOWAIT); 974 break; 975 case RPM_REQ_AUTOSUSPEND: 976 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO); 977 break; 978 case RPM_REQ_RESUME: 979 rpm_resume(dev, RPM_NOWAIT); 980 break; 981 } 982 983 out: 984 spin_unlock_irq(&dev->power.lock); 985} 986 987/** 988 * pm_suspend_timer_fn - Timer function for pm_schedule_suspend(). 989 * @timer: hrtimer used by pm_schedule_suspend(). 990 * 991 * Check if the time is right and queue a suspend request. 992 */ 993static enum hrtimer_restart pm_suspend_timer_fn(struct hrtimer *timer) 994{ 995 struct device *dev = container_of(timer, struct device, power.suspend_timer); 996 unsigned long flags; 997 u64 expires; 998 999 spin_lock_irqsave(&dev->power.lock, flags); 1000 1001 expires = dev->power.timer_expires; 1002 /* 1003 * If 'expires' is after the current time, we've been called 1004 * too early. 1005 */ 1006 if (expires > 0 && expires < ktime_get_mono_fast_ns()) { 1007 dev->power.timer_expires = 0; 1008 rpm_suspend(dev, dev->power.timer_autosuspends ? 1009 (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC); 1010 } 1011 1012 spin_unlock_irqrestore(&dev->power.lock, flags); 1013 1014 return HRTIMER_NORESTART; 1015} 1016 1017/** 1018 * pm_schedule_suspend - Set up a timer to submit a suspend request in future. 1019 * @dev: Device to suspend. 1020 * @delay: Time to wait before submitting a suspend request, in milliseconds. 1021 */ 1022int pm_schedule_suspend(struct device *dev, unsigned int delay) 1023{ 1024 unsigned long flags; 1025 u64 expires; 1026 int retval; 1027 1028 spin_lock_irqsave(&dev->power.lock, flags); 1029 1030 if (!delay) { 1031 retval = rpm_suspend(dev, RPM_ASYNC); 1032 goto out; 1033 } 1034 1035 retval = rpm_check_suspend_allowed(dev); 1036 if (retval) 1037 goto out; 1038 1039 /* Other scheduled or pending requests need to be canceled. */ 1040 pm_runtime_cancel_pending(dev); 1041 1042 expires = ktime_get_mono_fast_ns() + (u64)delay * NSEC_PER_MSEC; 1043 dev->power.timer_expires = expires; 1044 dev->power.timer_autosuspends = 0; 1045 hrtimer_start(&dev->power.suspend_timer, expires, HRTIMER_MODE_ABS); 1046 1047 out: 1048 spin_unlock_irqrestore(&dev->power.lock, flags); 1049 1050 return retval; 1051} 1052EXPORT_SYMBOL_GPL(pm_schedule_suspend); 1053 1054static int rpm_drop_usage_count(struct device *dev) 1055{ 1056 int ret; 1057 1058 ret = atomic_sub_return(1, &dev->power.usage_count); 1059 if (ret >= 0) 1060 return ret; 1061 1062 /* 1063 * Because rpm_resume() does not check the usage counter, it will resume 1064 * the device even if the usage counter is 0 or negative, so it is 1065 * sufficient to increment the usage counter here to reverse the change 1066 * made above. 1067 */ 1068 atomic_inc(&dev->power.usage_count); 1069 dev_warn(dev, "Runtime PM usage count underflow!\n"); 1070 return -EINVAL; 1071} 1072 1073/** 1074 * __pm_runtime_idle - Entry point for runtime idle operations. 1075 * @dev: Device to send idle notification for. 1076 * @rpmflags: Flag bits. 1077 * 1078 * If the RPM_GET_PUT flag is set, decrement the device's usage count and 1079 * return immediately if it is larger than zero (if it becomes negative, log a 1080 * warning, increment it, and return an error). Then carry out an idle 1081 * notification, either synchronous or asynchronous. 1082 * 1083 * This routine may be called in atomic context if the RPM_ASYNC flag is set, 1084 * or if pm_runtime_irq_safe() has been called. 1085 */ 1086int __pm_runtime_idle(struct device *dev, int rpmflags) 1087{ 1088 unsigned long flags; 1089 int retval; 1090 1091 if (rpmflags & RPM_GET_PUT) { 1092 retval = rpm_drop_usage_count(dev); 1093 if (retval < 0) { 1094 return retval; 1095 } else if (retval > 0) { 1096 trace_rpm_usage(dev, rpmflags); 1097 return 0; 1098 } 1099 } 1100 1101 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe); 1102 1103 spin_lock_irqsave(&dev->power.lock, flags); 1104 retval = rpm_idle(dev, rpmflags); 1105 spin_unlock_irqrestore(&dev->power.lock, flags); 1106 1107 return retval; 1108} 1109EXPORT_SYMBOL_GPL(__pm_runtime_idle); 1110 1111/** 1112 * __pm_runtime_suspend - Entry point for runtime put/suspend operations. 1113 * @dev: Device to suspend. 1114 * @rpmflags: Flag bits. 1115 * 1116 * If the RPM_GET_PUT flag is set, decrement the device's usage count and 1117 * return immediately if it is larger than zero (if it becomes negative, log a 1118 * warning, increment it, and return an error). Then carry out a suspend, 1119 * either synchronous or asynchronous. 1120 * 1121 * This routine may be called in atomic context if the RPM_ASYNC flag is set, 1122 * or if pm_runtime_irq_safe() has been called. 1123 */ 1124int __pm_runtime_suspend(struct device *dev, int rpmflags) 1125{ 1126 unsigned long flags; 1127 int retval; 1128 1129 if (rpmflags & RPM_GET_PUT) { 1130 retval = rpm_drop_usage_count(dev); 1131 if (retval < 0) { 1132 return retval; 1133 } else if (retval > 0) { 1134 trace_rpm_usage(dev, rpmflags); 1135 return 0; 1136 } 1137 } 1138 1139 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe); 1140 1141 spin_lock_irqsave(&dev->power.lock, flags); 1142 retval = rpm_suspend(dev, rpmflags); 1143 spin_unlock_irqrestore(&dev->power.lock, flags); 1144 1145 return retval; 1146} 1147EXPORT_SYMBOL_GPL(__pm_runtime_suspend); 1148 1149/** 1150 * __pm_runtime_resume - Entry point for runtime resume operations. 1151 * @dev: Device to resume. 1152 * @rpmflags: Flag bits. 1153 * 1154 * If the RPM_GET_PUT flag is set, increment the device's usage count. Then 1155 * carry out a resume, either synchronous or asynchronous. 1156 * 1157 * This routine may be called in atomic context if the RPM_ASYNC flag is set, 1158 * or if pm_runtime_irq_safe() has been called. 1159 */ 1160int __pm_runtime_resume(struct device *dev, int rpmflags) 1161{ 1162 unsigned long flags; 1163 int retval; 1164 1165 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe && 1166 dev->power.runtime_status != RPM_ACTIVE); 1167 1168 if (rpmflags & RPM_GET_PUT) 1169 atomic_inc(&dev->power.usage_count); 1170 1171 spin_lock_irqsave(&dev->power.lock, flags); 1172 retval = rpm_resume(dev, rpmflags); 1173 spin_unlock_irqrestore(&dev->power.lock, flags); 1174 1175 return retval; 1176} 1177EXPORT_SYMBOL_GPL(__pm_runtime_resume); 1178 1179/** 1180 * pm_runtime_get_conditional - Conditionally bump up device usage counter. 1181 * @dev: Device to handle. 1182 * @ign_usage_count: Whether or not to look at the current usage counter value. 1183 * 1184 * Return -EINVAL if runtime PM is disabled for @dev. 1185 * 1186 * Otherwise, if the runtime PM status of @dev is %RPM_ACTIVE and either 1187 * @ign_usage_count is %true or the runtime PM usage counter of @dev is not 1188 * zero, increment the usage counter of @dev and return 1. Otherwise, return 0 1189 * without changing the usage counter. 1190 * 1191 * If @ign_usage_count is %true, this function can be used to prevent suspending 1192 * the device when its runtime PM status is %RPM_ACTIVE. 1193 * 1194 * If @ign_usage_count is %false, this function can be used to prevent 1195 * suspending the device when both its runtime PM status is %RPM_ACTIVE and its 1196 * runtime PM usage counter is not zero. 1197 * 1198 * The caller is responsible for decrementing the runtime PM usage counter of 1199 * @dev after this function has returned a positive value for it. 1200 */ 1201static int pm_runtime_get_conditional(struct device *dev, bool ign_usage_count) 1202{ 1203 unsigned long flags; 1204 int retval; 1205 1206 spin_lock_irqsave(&dev->power.lock, flags); 1207 if (dev->power.disable_depth > 0) { 1208 retval = -EINVAL; 1209 } else if (dev->power.runtime_status != RPM_ACTIVE) { 1210 retval = 0; 1211 } else if (ign_usage_count) { 1212 retval = 1; 1213 atomic_inc(&dev->power.usage_count); 1214 } else { 1215 retval = atomic_inc_not_zero(&dev->power.usage_count); 1216 } 1217 trace_rpm_usage(dev, 0); 1218 spin_unlock_irqrestore(&dev->power.lock, flags); 1219 1220 return retval; 1221} 1222 1223/** 1224 * pm_runtime_get_if_active - Bump up runtime PM usage counter if the device is 1225 * in active state 1226 * @dev: Target device. 1227 * 1228 * Increment the runtime PM usage counter of @dev if its runtime PM status is 1229 * %RPM_ACTIVE, in which case it returns 1. If the device is in a different 1230 * state, 0 is returned. -EINVAL is returned if runtime PM is disabled for the 1231 * device, in which case also the usage_count will remain unmodified. 1232 */ 1233int pm_runtime_get_if_active(struct device *dev) 1234{ 1235 return pm_runtime_get_conditional(dev, true); 1236} 1237EXPORT_SYMBOL_GPL(pm_runtime_get_if_active); 1238 1239/** 1240 * pm_runtime_get_if_in_use - Conditionally bump up runtime PM usage counter. 1241 * @dev: Target device. 1242 * 1243 * Increment the runtime PM usage counter of @dev if its runtime PM status is 1244 * %RPM_ACTIVE and its runtime PM usage counter is greater than 0, in which case 1245 * it returns 1. If the device is in a different state or its usage_count is 0, 1246 * 0 is returned. -EINVAL is returned if runtime PM is disabled for the device, 1247 * in which case also the usage_count will remain unmodified. 1248 */ 1249int pm_runtime_get_if_in_use(struct device *dev) 1250{ 1251 return pm_runtime_get_conditional(dev, false); 1252} 1253EXPORT_SYMBOL_GPL(pm_runtime_get_if_in_use); 1254 1255/** 1256 * __pm_runtime_set_status - Set runtime PM status of a device. 1257 * @dev: Device to handle. 1258 * @status: New runtime PM status of the device. 1259 * 1260 * If runtime PM of the device is disabled or its power.runtime_error field is 1261 * different from zero, the status may be changed either to RPM_ACTIVE, or to 1262 * RPM_SUSPENDED, as long as that reflects the actual state of the device. 1263 * However, if the device has a parent and the parent is not active, and the 1264 * parent's power.ignore_children flag is unset, the device's status cannot be 1265 * set to RPM_ACTIVE, so -EBUSY is returned in that case. 1266 * 1267 * If successful, __pm_runtime_set_status() clears the power.runtime_error field 1268 * and the device parent's counter of unsuspended children is modified to 1269 * reflect the new status. If the new status is RPM_SUSPENDED, an idle 1270 * notification request for the parent is submitted. 1271 * 1272 * If @dev has any suppliers (as reflected by device links to them), and @status 1273 * is RPM_ACTIVE, they will be activated upfront and if the activation of one 1274 * of them fails, the status of @dev will be changed to RPM_SUSPENDED (instead 1275 * of the @status value) and the suppliers will be deacticated on exit. The 1276 * error returned by the failing supplier activation will be returned in that 1277 * case. 1278 */ 1279int __pm_runtime_set_status(struct device *dev, unsigned int status) 1280{ 1281 struct device *parent = dev->parent; 1282 bool notify_parent = false; 1283 unsigned long flags; 1284 int error = 0; 1285 1286 if (status != RPM_ACTIVE && status != RPM_SUSPENDED) 1287 return -EINVAL; 1288 1289 spin_lock_irqsave(&dev->power.lock, flags); 1290 1291 /* 1292 * Prevent PM-runtime from being enabled for the device or return an 1293 * error if it is enabled already and working. 1294 */ 1295 if (dev->power.runtime_error || dev->power.disable_depth) 1296 dev->power.disable_depth++; 1297 else 1298 error = -EAGAIN; 1299 1300 spin_unlock_irqrestore(&dev->power.lock, flags); 1301 1302 if (error) 1303 return error; 1304 1305 /* 1306 * If the new status is RPM_ACTIVE, the suppliers can be activated 1307 * upfront regardless of the current status, because next time 1308 * rpm_put_suppliers() runs, the rpm_active refcounts of the links 1309 * involved will be dropped down to one anyway. 1310 */ 1311 if (status == RPM_ACTIVE) { 1312 int idx = device_links_read_lock(); 1313 1314 error = rpm_get_suppliers(dev); 1315 if (error) 1316 status = RPM_SUSPENDED; 1317 1318 device_links_read_unlock(idx); 1319 } 1320 1321 spin_lock_irqsave(&dev->power.lock, flags); 1322 1323 if (dev->power.runtime_status == status || !parent) 1324 goto out_set; 1325 1326 if (status == RPM_SUSPENDED) { 1327 atomic_add_unless(&parent->power.child_count, -1, 0); 1328 notify_parent = !parent->power.ignore_children; 1329 } else { 1330 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING); 1331 1332 /* 1333 * It is invalid to put an active child under a parent that is 1334 * not active, has runtime PM enabled and the 1335 * 'power.ignore_children' flag unset. 1336 */ 1337 if (!parent->power.disable_depth && 1338 !parent->power.ignore_children && 1339 parent->power.runtime_status != RPM_ACTIVE) { 1340 dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n", 1341 dev_name(dev), 1342 dev_name(parent)); 1343 error = -EBUSY; 1344 } else if (dev->power.runtime_status == RPM_SUSPENDED) { 1345 atomic_inc(&parent->power.child_count); 1346 } 1347 1348 spin_unlock(&parent->power.lock); 1349 1350 if (error) { 1351 status = RPM_SUSPENDED; 1352 goto out; 1353 } 1354 } 1355 1356 out_set: 1357 __update_runtime_status(dev, status); 1358 if (!error) 1359 dev->power.runtime_error = 0; 1360 1361 out: 1362 spin_unlock_irqrestore(&dev->power.lock, flags); 1363 1364 if (notify_parent) 1365 pm_request_idle(parent); 1366 1367 if (status == RPM_SUSPENDED) { 1368 int idx = device_links_read_lock(); 1369 1370 rpm_put_suppliers(dev); 1371 1372 device_links_read_unlock(idx); 1373 } 1374 1375 pm_runtime_enable(dev); 1376 1377 return error; 1378} 1379EXPORT_SYMBOL_GPL(__pm_runtime_set_status); 1380 1381/** 1382 * __pm_runtime_barrier - Cancel pending requests and wait for completions. 1383 * @dev: Device to handle. 1384 * 1385 * Flush all pending requests for the device from pm_wq and wait for all 1386 * runtime PM operations involving the device in progress to complete. 1387 * 1388 * Should be called under dev->power.lock with interrupts disabled. 1389 */ 1390static void __pm_runtime_barrier(struct device *dev) 1391{ 1392 pm_runtime_deactivate_timer(dev); 1393 1394 if (dev->power.request_pending) { 1395 dev->power.request = RPM_REQ_NONE; 1396 spin_unlock_irq(&dev->power.lock); 1397 1398 cancel_work_sync(&dev->power.work); 1399 1400 spin_lock_irq(&dev->power.lock); 1401 dev->power.request_pending = false; 1402 } 1403 1404 if (dev->power.runtime_status == RPM_SUSPENDING || 1405 dev->power.runtime_status == RPM_RESUMING || 1406 dev->power.idle_notification) { 1407 DEFINE_WAIT(wait); 1408 1409 /* Suspend, wake-up or idle notification in progress. */ 1410 for (;;) { 1411 prepare_to_wait(&dev->power.wait_queue, &wait, 1412 TASK_UNINTERRUPTIBLE); 1413 if (dev->power.runtime_status != RPM_SUSPENDING 1414 && dev->power.runtime_status != RPM_RESUMING 1415 && !dev->power.idle_notification) 1416 break; 1417 spin_unlock_irq(&dev->power.lock); 1418 1419 schedule(); 1420 1421 spin_lock_irq(&dev->power.lock); 1422 } 1423 finish_wait(&dev->power.wait_queue, &wait); 1424 } 1425} 1426 1427/** 1428 * pm_runtime_barrier - Flush pending requests and wait for completions. 1429 * @dev: Device to handle. 1430 * 1431 * Prevent the device from being suspended by incrementing its usage counter and 1432 * if there's a pending resume request for the device, wake the device up. 1433 * Next, make sure that all pending requests for the device have been flushed 1434 * from pm_wq and wait for all runtime PM operations involving the device in 1435 * progress to complete. 1436 * 1437 * Return value: 1438 * 1, if there was a resume request pending and the device had to be woken up, 1439 * 0, otherwise 1440 */ 1441int pm_runtime_barrier(struct device *dev) 1442{ 1443 int retval = 0; 1444 1445 pm_runtime_get_noresume(dev); 1446 spin_lock_irq(&dev->power.lock); 1447 1448 if (dev->power.request_pending 1449 && dev->power.request == RPM_REQ_RESUME) { 1450 rpm_resume(dev, 0); 1451 retval = 1; 1452 } 1453 1454 __pm_runtime_barrier(dev); 1455 1456 spin_unlock_irq(&dev->power.lock); 1457 pm_runtime_put_noidle(dev); 1458 1459 return retval; 1460} 1461EXPORT_SYMBOL_GPL(pm_runtime_barrier); 1462 1463/** 1464 * __pm_runtime_disable - Disable runtime PM of a device. 1465 * @dev: Device to handle. 1466 * @check_resume: If set, check if there's a resume request for the device. 1467 * 1468 * Increment power.disable_depth for the device and if it was zero previously, 1469 * cancel all pending runtime PM requests for the device and wait for all 1470 * operations in progress to complete. The device can be either active or 1471 * suspended after its runtime PM has been disabled. 1472 * 1473 * If @check_resume is set and there's a resume request pending when 1474 * __pm_runtime_disable() is called and power.disable_depth is zero, the 1475 * function will wake up the device before disabling its runtime PM. 1476 */ 1477void __pm_runtime_disable(struct device *dev, bool check_resume) 1478{ 1479 spin_lock_irq(&dev->power.lock); 1480 1481 if (dev->power.disable_depth > 0) { 1482 dev->power.disable_depth++; 1483 goto out; 1484 } 1485 1486 /* 1487 * Wake up the device if there's a resume request pending, because that 1488 * means there probably is some I/O to process and disabling runtime PM 1489 * shouldn't prevent the device from processing the I/O. 1490 */ 1491 if (check_resume && dev->power.request_pending && 1492 dev->power.request == RPM_REQ_RESUME) { 1493 /* 1494 * Prevent suspends and idle notifications from being carried 1495 * out after we have woken up the device. 1496 */ 1497 pm_runtime_get_noresume(dev); 1498 1499 rpm_resume(dev, 0); 1500 1501 pm_runtime_put_noidle(dev); 1502 } 1503 1504 /* Update time accounting before disabling PM-runtime. */ 1505 update_pm_runtime_accounting(dev); 1506 1507 if (!dev->power.disable_depth++) { 1508 __pm_runtime_barrier(dev); 1509 dev->power.last_status = dev->power.runtime_status; 1510 } 1511 1512 out: 1513 spin_unlock_irq(&dev->power.lock); 1514} 1515EXPORT_SYMBOL_GPL(__pm_runtime_disable); 1516 1517/** 1518 * pm_runtime_enable - Enable runtime PM of a device. 1519 * @dev: Device to handle. 1520 */ 1521void pm_runtime_enable(struct device *dev) 1522{ 1523 unsigned long flags; 1524 1525 spin_lock_irqsave(&dev->power.lock, flags); 1526 1527 if (!dev->power.disable_depth) { 1528 dev_warn(dev, "Unbalanced %s!\n", __func__); 1529 goto out; 1530 } 1531 1532 if (--dev->power.disable_depth > 0) 1533 goto out; 1534 1535 dev->power.last_status = RPM_INVALID; 1536 dev->power.accounting_timestamp = ktime_get_mono_fast_ns(); 1537 1538 if (dev->power.runtime_status == RPM_SUSPENDED && 1539 !dev->power.ignore_children && 1540 atomic_read(&dev->power.child_count) > 0) 1541 dev_warn(dev, "Enabling runtime PM for inactive device with active children\n"); 1542 1543out: 1544 spin_unlock_irqrestore(&dev->power.lock, flags); 1545} 1546EXPORT_SYMBOL_GPL(pm_runtime_enable); 1547 1548static void pm_runtime_disable_action(void *data) 1549{ 1550 pm_runtime_dont_use_autosuspend(data); 1551 pm_runtime_disable(data); 1552} 1553 1554/** 1555 * devm_pm_runtime_enable - devres-enabled version of pm_runtime_enable. 1556 * 1557 * NOTE: this will also handle calling pm_runtime_dont_use_autosuspend() for 1558 * you at driver exit time if needed. 1559 * 1560 * @dev: Device to handle. 1561 */ 1562int devm_pm_runtime_enable(struct device *dev) 1563{ 1564 pm_runtime_enable(dev); 1565 1566 return devm_add_action_or_reset(dev, pm_runtime_disable_action, dev); 1567} 1568EXPORT_SYMBOL_GPL(devm_pm_runtime_enable); 1569 1570/** 1571 * pm_runtime_forbid - Block runtime PM of a device. 1572 * @dev: Device to handle. 1573 * 1574 * Increase the device's usage count and clear its power.runtime_auto flag, 1575 * so that it cannot be suspended at run time until pm_runtime_allow() is called 1576 * for it. 1577 */ 1578void pm_runtime_forbid(struct device *dev) 1579{ 1580 spin_lock_irq(&dev->power.lock); 1581 if (!dev->power.runtime_auto) 1582 goto out; 1583 1584 dev->power.runtime_auto = false; 1585 atomic_inc(&dev->power.usage_count); 1586 rpm_resume(dev, 0); 1587 1588 out: 1589 spin_unlock_irq(&dev->power.lock); 1590} 1591EXPORT_SYMBOL_GPL(pm_runtime_forbid); 1592 1593/** 1594 * pm_runtime_allow - Unblock runtime PM of a device. 1595 * @dev: Device to handle. 1596 * 1597 * Decrease the device's usage count and set its power.runtime_auto flag. 1598 */ 1599void pm_runtime_allow(struct device *dev) 1600{ 1601 int ret; 1602 1603 spin_lock_irq(&dev->power.lock); 1604 if (dev->power.runtime_auto) 1605 goto out; 1606 1607 dev->power.runtime_auto = true; 1608 ret = rpm_drop_usage_count(dev); 1609 if (ret == 0) 1610 rpm_idle(dev, RPM_AUTO | RPM_ASYNC); 1611 else if (ret > 0) 1612 trace_rpm_usage(dev, RPM_AUTO | RPM_ASYNC); 1613 1614 out: 1615 spin_unlock_irq(&dev->power.lock); 1616} 1617EXPORT_SYMBOL_GPL(pm_runtime_allow); 1618 1619/** 1620 * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device. 1621 * @dev: Device to handle. 1622 * 1623 * Set the power.no_callbacks flag, which tells the PM core that this 1624 * device is power-managed through its parent and has no runtime PM 1625 * callbacks of its own. The runtime sysfs attributes will be removed. 1626 */ 1627void pm_runtime_no_callbacks(struct device *dev) 1628{ 1629 spin_lock_irq(&dev->power.lock); 1630 dev->power.no_callbacks = 1; 1631 spin_unlock_irq(&dev->power.lock); 1632 if (device_is_registered(dev)) 1633 rpm_sysfs_remove(dev); 1634} 1635EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks); 1636 1637/** 1638 * pm_runtime_irq_safe - Leave interrupts disabled during callbacks. 1639 * @dev: Device to handle 1640 * 1641 * Set the power.irq_safe flag, which tells the PM core that the 1642 * ->runtime_suspend() and ->runtime_resume() callbacks for this device should 1643 * always be invoked with the spinlock held and interrupts disabled. It also 1644 * causes the parent's usage counter to be permanently incremented, preventing 1645 * the parent from runtime suspending -- otherwise an irq-safe child might have 1646 * to wait for a non-irq-safe parent. 1647 */ 1648void pm_runtime_irq_safe(struct device *dev) 1649{ 1650 if (dev->parent) 1651 pm_runtime_get_sync(dev->parent); 1652 1653 spin_lock_irq(&dev->power.lock); 1654 dev->power.irq_safe = 1; 1655 spin_unlock_irq(&dev->power.lock); 1656} 1657EXPORT_SYMBOL_GPL(pm_runtime_irq_safe); 1658 1659/** 1660 * update_autosuspend - Handle a change to a device's autosuspend settings. 1661 * @dev: Device to handle. 1662 * @old_delay: The former autosuspend_delay value. 1663 * @old_use: The former use_autosuspend value. 1664 * 1665 * Prevent runtime suspend if the new delay is negative and use_autosuspend is 1666 * set; otherwise allow it. Send an idle notification if suspends are allowed. 1667 * 1668 * This function must be called under dev->power.lock with interrupts disabled. 1669 */ 1670static void update_autosuspend(struct device *dev, int old_delay, int old_use) 1671{ 1672 int delay = dev->power.autosuspend_delay; 1673 1674 /* Should runtime suspend be prevented now? */ 1675 if (dev->power.use_autosuspend && delay < 0) { 1676 1677 /* If it used to be allowed then prevent it. */ 1678 if (!old_use || old_delay >= 0) { 1679 atomic_inc(&dev->power.usage_count); 1680 rpm_resume(dev, 0); 1681 } else { 1682 trace_rpm_usage(dev, 0); 1683 } 1684 } 1685 1686 /* Runtime suspend should be allowed now. */ 1687 else { 1688 1689 /* If it used to be prevented then allow it. */ 1690 if (old_use && old_delay < 0) 1691 atomic_dec(&dev->power.usage_count); 1692 1693 /* Maybe we can autosuspend now. */ 1694 rpm_idle(dev, RPM_AUTO); 1695 } 1696} 1697 1698/** 1699 * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value. 1700 * @dev: Device to handle. 1701 * @delay: Value of the new delay in milliseconds. 1702 * 1703 * Set the device's power.autosuspend_delay value. If it changes to negative 1704 * and the power.use_autosuspend flag is set, prevent runtime suspends. If it 1705 * changes the other way, allow runtime suspends. 1706 */ 1707void pm_runtime_set_autosuspend_delay(struct device *dev, int delay) 1708{ 1709 int old_delay, old_use; 1710 1711 spin_lock_irq(&dev->power.lock); 1712 old_delay = dev->power.autosuspend_delay; 1713 old_use = dev->power.use_autosuspend; 1714 dev->power.autosuspend_delay = delay; 1715 update_autosuspend(dev, old_delay, old_use); 1716 spin_unlock_irq(&dev->power.lock); 1717} 1718EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay); 1719 1720/** 1721 * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag. 1722 * @dev: Device to handle. 1723 * @use: New value for use_autosuspend. 1724 * 1725 * Set the device's power.use_autosuspend flag, and allow or prevent runtime 1726 * suspends as needed. 1727 */ 1728void __pm_runtime_use_autosuspend(struct device *dev, bool use) 1729{ 1730 int old_delay, old_use; 1731 1732 spin_lock_irq(&dev->power.lock); 1733 old_delay = dev->power.autosuspend_delay; 1734 old_use = dev->power.use_autosuspend; 1735 dev->power.use_autosuspend = use; 1736 update_autosuspend(dev, old_delay, old_use); 1737 spin_unlock_irq(&dev->power.lock); 1738} 1739EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend); 1740 1741/** 1742 * pm_runtime_init - Initialize runtime PM fields in given device object. 1743 * @dev: Device object to initialize. 1744 */ 1745void pm_runtime_init(struct device *dev) 1746{ 1747 dev->power.runtime_status = RPM_SUSPENDED; 1748 dev->power.last_status = RPM_INVALID; 1749 dev->power.idle_notification = false; 1750 1751 dev->power.disable_depth = 1; 1752 atomic_set(&dev->power.usage_count, 0); 1753 1754 dev->power.runtime_error = 0; 1755 1756 atomic_set(&dev->power.child_count, 0); 1757 pm_suspend_ignore_children(dev, false); 1758 dev->power.runtime_auto = true; 1759 1760 dev->power.request_pending = false; 1761 dev->power.request = RPM_REQ_NONE; 1762 dev->power.deferred_resume = false; 1763 dev->power.needs_force_resume = 0; 1764 INIT_WORK(&dev->power.work, pm_runtime_work); 1765 1766 dev->power.timer_expires = 0; 1767 hrtimer_init(&dev->power.suspend_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); 1768 dev->power.suspend_timer.function = pm_suspend_timer_fn; 1769 1770 init_waitqueue_head(&dev->power.wait_queue); 1771} 1772 1773/** 1774 * pm_runtime_reinit - Re-initialize runtime PM fields in given device object. 1775 * @dev: Device object to re-initialize. 1776 */ 1777void pm_runtime_reinit(struct device *dev) 1778{ 1779 if (!pm_runtime_enabled(dev)) { 1780 if (dev->power.runtime_status == RPM_ACTIVE) 1781 pm_runtime_set_suspended(dev); 1782 if (dev->power.irq_safe) { 1783 spin_lock_irq(&dev->power.lock); 1784 dev->power.irq_safe = 0; 1785 spin_unlock_irq(&dev->power.lock); 1786 if (dev->parent) 1787 pm_runtime_put(dev->parent); 1788 } 1789 } 1790} 1791 1792/** 1793 * pm_runtime_remove - Prepare for removing a device from device hierarchy. 1794 * @dev: Device object being removed from device hierarchy. 1795 */ 1796void pm_runtime_remove(struct device *dev) 1797{ 1798 __pm_runtime_disable(dev, false); 1799 pm_runtime_reinit(dev); 1800} 1801 1802/** 1803 * pm_runtime_get_suppliers - Resume and reference-count supplier devices. 1804 * @dev: Consumer device. 1805 */ 1806void pm_runtime_get_suppliers(struct device *dev) 1807{ 1808 struct device_link *link; 1809 int idx; 1810 1811 idx = device_links_read_lock(); 1812 1813 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node, 1814 device_links_read_lock_held()) 1815 if (link->flags & DL_FLAG_PM_RUNTIME) { 1816 link->supplier_preactivated = true; 1817 pm_runtime_get_sync(link->supplier); 1818 } 1819 1820 device_links_read_unlock(idx); 1821} 1822 1823/** 1824 * pm_runtime_put_suppliers - Drop references to supplier devices. 1825 * @dev: Consumer device. 1826 */ 1827void pm_runtime_put_suppliers(struct device *dev) 1828{ 1829 struct device_link *link; 1830 int idx; 1831 1832 idx = device_links_read_lock(); 1833 1834 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node, 1835 device_links_read_lock_held()) 1836 if (link->supplier_preactivated) { 1837 link->supplier_preactivated = false; 1838 pm_runtime_put(link->supplier); 1839 } 1840 1841 device_links_read_unlock(idx); 1842} 1843 1844void pm_runtime_new_link(struct device *dev) 1845{ 1846 spin_lock_irq(&dev->power.lock); 1847 dev->power.links_count++; 1848 spin_unlock_irq(&dev->power.lock); 1849} 1850 1851static void pm_runtime_drop_link_count(struct device *dev) 1852{ 1853 spin_lock_irq(&dev->power.lock); 1854 WARN_ON(dev->power.links_count == 0); 1855 dev->power.links_count--; 1856 spin_unlock_irq(&dev->power.lock); 1857} 1858 1859/** 1860 * pm_runtime_drop_link - Prepare for device link removal. 1861 * @link: Device link going away. 1862 * 1863 * Drop the link count of the consumer end of @link and decrement the supplier 1864 * device's runtime PM usage counter as many times as needed to drop all of the 1865 * PM runtime reference to it from the consumer. 1866 */ 1867void pm_runtime_drop_link(struct device_link *link) 1868{ 1869 if (!(link->flags & DL_FLAG_PM_RUNTIME)) 1870 return; 1871 1872 pm_runtime_drop_link_count(link->consumer); 1873 pm_runtime_release_supplier(link); 1874 pm_request_idle(link->supplier); 1875} 1876 1877static bool pm_runtime_need_not_resume(struct device *dev) 1878{ 1879 return atomic_read(&dev->power.usage_count) <= 1 && 1880 (atomic_read(&dev->power.child_count) == 0 || 1881 dev->power.ignore_children); 1882} 1883 1884/** 1885 * pm_runtime_force_suspend - Force a device into suspend state if needed. 1886 * @dev: Device to suspend. 1887 * 1888 * Disable runtime PM so we safely can check the device's runtime PM status and 1889 * if it is active, invoke its ->runtime_suspend callback to suspend it and 1890 * change its runtime PM status field to RPM_SUSPENDED. Also, if the device's 1891 * usage and children counters don't indicate that the device was in use before 1892 * the system-wide transition under way, decrement its parent's children counter 1893 * (if there is a parent). Keep runtime PM disabled to preserve the state 1894 * unless we encounter errors. 1895 * 1896 * Typically this function may be invoked from a system suspend callback to make 1897 * sure the device is put into low power state and it should only be used during 1898 * system-wide PM transitions to sleep states. It assumes that the analogous 1899 * pm_runtime_force_resume() will be used to resume the device. 1900 * 1901 * Do not use with DPM_FLAG_SMART_SUSPEND as this can lead to an inconsistent 1902 * state where this function has called the ->runtime_suspend callback but the 1903 * PM core marks the driver as runtime active. 1904 */ 1905int pm_runtime_force_suspend(struct device *dev) 1906{ 1907 int (*callback)(struct device *); 1908 int ret; 1909 1910 pm_runtime_disable(dev); 1911 if (pm_runtime_status_suspended(dev)) 1912 return 0; 1913 1914 callback = RPM_GET_CALLBACK(dev, runtime_suspend); 1915 1916 dev_pm_enable_wake_irq_check(dev, true); 1917 ret = callback ? callback(dev) : 0; 1918 if (ret) 1919 goto err; 1920 1921 dev_pm_enable_wake_irq_complete(dev); 1922 1923 /* 1924 * If the device can stay in suspend after the system-wide transition 1925 * to the working state that will follow, drop the children counter of 1926 * its parent, but set its status to RPM_SUSPENDED anyway in case this 1927 * function will be called again for it in the meantime. 1928 */ 1929 if (pm_runtime_need_not_resume(dev)) { 1930 pm_runtime_set_suspended(dev); 1931 } else { 1932 __update_runtime_status(dev, RPM_SUSPENDED); 1933 dev->power.needs_force_resume = 1; 1934 } 1935 1936 return 0; 1937 1938err: 1939 dev_pm_disable_wake_irq_check(dev, true); 1940 pm_runtime_enable(dev); 1941 return ret; 1942} 1943EXPORT_SYMBOL_GPL(pm_runtime_force_suspend); 1944 1945/** 1946 * pm_runtime_force_resume - Force a device into resume state if needed. 1947 * @dev: Device to resume. 1948 * 1949 * Prior invoking this function we expect the user to have brought the device 1950 * into low power state by a call to pm_runtime_force_suspend(). Here we reverse 1951 * those actions and bring the device into full power, if it is expected to be 1952 * used on system resume. In the other case, we defer the resume to be managed 1953 * via runtime PM. 1954 * 1955 * Typically this function may be invoked from a system resume callback. 1956 */ 1957int pm_runtime_force_resume(struct device *dev) 1958{ 1959 int (*callback)(struct device *); 1960 int ret = 0; 1961 1962 if (!pm_runtime_status_suspended(dev) || !dev->power.needs_force_resume) 1963 goto out; 1964 1965 /* 1966 * The value of the parent's children counter is correct already, so 1967 * just update the status of the device. 1968 */ 1969 __update_runtime_status(dev, RPM_ACTIVE); 1970 1971 callback = RPM_GET_CALLBACK(dev, runtime_resume); 1972 1973 dev_pm_disable_wake_irq_check(dev, false); 1974 ret = callback ? callback(dev) : 0; 1975 if (ret) { 1976 pm_runtime_set_suspended(dev); 1977 dev_pm_enable_wake_irq_check(dev, false); 1978 goto out; 1979 } 1980 1981 pm_runtime_mark_last_busy(dev); 1982out: 1983 dev->power.needs_force_resume = 0; 1984 pm_runtime_enable(dev); 1985 return ret; 1986} 1987EXPORT_SYMBOL_GPL(pm_runtime_force_resume); 1988