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