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