drivers/base/power/qos.c

   1 /*
   2  * Devices PM QoS constraints management
   3  *
   4  * Copyright (C) 2011 Texas Instruments, Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  *
  11  * This module exposes the interface to kernel space for specifying
  12  * per-device PM QoS dependencies. It provides infrastructure for registration
  13  * of:
  14  *
  15  * Dependents on a QoS value : register requests
  16  * Watchers of QoS value : get notified when target QoS value changes
  17  *
  18  * This QoS design is best effort based. Dependents register their QoS needs.
  19  * Watchers register to keep track of the current QoS needs of the system.
  20  * Watchers can register different types of notification callbacks:
  21  *  . a per-device notification callback using the dev_pm_qos_*_notifier API.
  22  *    The notification chain data is stored in the per-device constraint
  23  *    data struct.
  24  *  . a system-wide notification callback using the dev_pm_qos_*_global_notifier
  25  *    API. The notification chain data is stored in a static variable.
  26  *
  27  * Note about the per-device constraint data struct allocation:
  28  * . The per-device constraints data struct ptr is tored into the device
  29  *    dev_pm_info.
  30  * . To minimize the data usage by the per-device constraints, the data struct
  31  *   is only allocated at the first call to dev_pm_qos_add_request.
  32  * . The data is later free'd when the device is removed from the system.
  33  *  . A global mutex protects the constraints users from the data being
  34  *     allocated and free'd.
  35  */
  36
  37 #include <linux/pm_qos.h>
  38 #include <linux/spinlock.h>
  39 #include <linux/slab.h>
  40 #include <linux/device.h>
  41 #include <linux/mutex.h>
  42 #include <linux/export.h>
  43 #include <linux/pm_runtime.h>
  44 #include <linux/err.h>
  45
  46 #include "power.h"
  47
  48 static DEFINE_MUTEX(dev_pm_qos_mtx);
  49 static DEFINE_MUTEX(dev_pm_qos_sysfs_mtx);
  50
  51 static BLOCKING_NOTIFIER_HEAD(dev_pm_notifiers);
  52
  53 /**
  54  * __dev_pm_qos_flags - Check PM QoS flags for a given device.
  55  * @dev: Device to check the PM QoS flags for.
  56  * @mask: Flags to check against.
  57  *
  58  * This routine must be called with dev->power.lock held.
  59  */
  60 enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask)
  61 {
  62         struct dev_pm_qos *qos = dev->power.qos;
  63         struct pm_qos_flags *pqf;
  64         s32 val;
  65
  66         if (IS_ERR_OR_NULL(qos))
  67                 return PM_QOS_FLAGS_UNDEFINED;
  68
  69         pqf = &qos->flags;
  70         if (list_empty(&pqf->list))
  71                 return PM_QOS_FLAGS_UNDEFINED;
  72
  73         val = pqf->effective_flags & mask;
  74         if (val)
  75                 return (val == mask) ? PM_QOS_FLAGS_ALL : PM_QOS_FLAGS_SOME;
  76
  77         return PM_QOS_FLAGS_NONE;
  78 }
  79
  80 /**
  81  * dev_pm_qos_flags - Check PM QoS flags for a given device (locked).
  82  * @dev: Device to check the PM QoS flags for.
  83  * @mask: Flags to check against.
  84  */
  85 enum pm_qos_flags_status dev_pm_qos_flags(struct device *dev, s32 mask)
  86 {
  87         unsigned long irqflags;
  88         enum pm_qos_flags_status ret;
  89
  90         spin_lock_irqsave(&dev->power.lock, irqflags);
  91         ret = __dev_pm_qos_flags(dev, mask);
  92         spin_unlock_irqrestore(&dev->power.lock, irqflags);
  93
  94         return ret;
  95 }
  96 EXPORT_SYMBOL_GPL(dev_pm_qos_flags);
  97
  98 /**
  99  * __dev_pm_qos_read_value - Get PM QoS constraint for a given device.
 100  * @dev: Device to get the PM QoS constraint value for.
 101  *
 102  * This routine must be called with dev->power.lock held.
 103  */
 104 s32 __dev_pm_qos_read_value(struct device *dev)
 105 {
 106         return IS_ERR_OR_NULL(dev->power.qos) ?
 107                 0 : pm_qos_read_value(&dev->power.qos->latency);
 108 }
 109
 110 /**
 111  * dev_pm_qos_read_value - Get PM QoS constraint for a given device (locked).
 112  * @dev: Device to get the PM QoS constraint value for.
 113  */
 114 s32 dev_pm_qos_read_value(struct device *dev)
 115 {
 116         unsigned long flags;
 117         s32 ret;
 118
 119         spin_lock_irqsave(&dev->power.lock, flags);
 120         ret = __dev_pm_qos_read_value(dev);
 121         spin_unlock_irqrestore(&dev->power.lock, flags);
 122
 123         return ret;
 124 }
 125
 126 /**
 127  * apply_constraint - Add/modify/remove device PM QoS request.
 128  * @req: Constraint request to apply
 129  * @action: Action to perform (add/update/remove).
 130  * @value: Value to assign to the QoS request.
 131  *
 132  * Internal function to update the constraints list using the PM QoS core
 133  * code and if needed call the per-device and the global notification
 134  * callbacks
 135  */
 136 static int apply_constraint(struct dev_pm_qos_request *req,
 137                             enum pm_qos_req_action action, s32 value)
 138 {
 139         struct dev_pm_qos *qos = req->dev->power.qos;
 140         int ret;
 141
 142         switch(req->type) {
 143         case DEV_PM_QOS_LATENCY:
 144                 ret = pm_qos_update_target(&qos->latency, &req->data.pnode,
 145                                            action, value);
 146                 if (ret) {
 147                         value = pm_qos_read_value(&qos->latency);
 148                         blocking_notifier_call_chain(&dev_pm_notifiers,
 149                                                      (unsigned long)value,
 150                                                      req);
 151                 }
 152                 break;
 153         case DEV_PM_QOS_FLAGS:
 154                 ret = pm_qos_update_flags(&qos->flags, &req->data.flr,
 155                                           action, value);
 156                 break;
 157         default:
 158                 ret = -EINVAL;
 159         }
 160
 161         return ret;
 162 }
 163
 164 /*
 165  * dev_pm_qos_constraints_allocate
 166  * @dev: device to allocate data for
 167  *
 168  * Called at the first call to add_request, for constraint data allocation
 169  * Must be called with the dev_pm_qos_mtx mutex held
 170  */
 171 static int dev_pm_qos_constraints_allocate(struct device *dev)
 172 {
 173         struct dev_pm_qos *qos;
 174         struct pm_qos_constraints *c;
 175         struct blocking_notifier_head *n;
 176
 177         qos = kzalloc(sizeof(*qos), GFP_KERNEL);
 178         if (!qos)
 179                 return -ENOMEM;
 180
 181         n = kzalloc(sizeof(*n), GFP_KERNEL);
 182         if (!n) {
 183                 kfree(qos);
 184                 return -ENOMEM;
 185         }
 186         BLOCKING_INIT_NOTIFIER_HEAD(n);
 187
 188         c = &qos->latency;
 189         plist_head_init(&c->list);
 190         c->target_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
 191         c->default_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
 192         c->type = PM_QOS_MIN;
 193         c->notifiers = n;
 194
 195         INIT_LIST_HEAD(&qos->flags.list);
 196
 197         spin_lock_irq(&dev->power.lock);
 198         dev->power.qos = qos;
 199         spin_unlock_irq(&dev->power.lock);
 200
 201         return 0;
 202 }
 203
 204 static void __dev_pm_qos_hide_latency_limit(struct device *dev);
 205 static void __dev_pm_qos_hide_flags(struct device *dev);
 206
 207 /**
 208  * dev_pm_qos_constraints_destroy
 209  * @dev: target device
 210  *
 211  * Called from the device PM subsystem on device removal under device_pm_lock().
 212  */
 213 void dev_pm_qos_constraints_destroy(struct device *dev)
 214 {
 215         struct dev_pm_qos *qos;
 216         struct dev_pm_qos_request *req, *tmp;
 217         struct pm_qos_constraints *c;
 218         struct pm_qos_flags *f;
 219
 220         mutex_lock(&dev_pm_qos_sysfs_mtx);
 221
 222         /*
 223          * If the device's PM QoS resume latency limit or PM QoS flags have been
 224          * exposed to user space, they have to be hidden at this point.
 225          */
 226         pm_qos_sysfs_remove_latency(dev);
 227         pm_qos_sysfs_remove_flags(dev);
 228
 229         mutex_lock(&dev_pm_qos_mtx);
 230
 231         __dev_pm_qos_hide_latency_limit(dev);
 232         __dev_pm_qos_hide_flags(dev);
 233
 234         qos = dev->power.qos;
 235         if (!qos)
 236                 goto out;
 237
 238         /* Flush the constraints lists for the device. */
 239         c = &qos->latency;
 240         plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
 241                 /*
 242                  * Update constraints list and call the notification
 243                  * callbacks if needed
 244                  */
 245                 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
 246                 memset(req, 0, sizeof(*req));
 247         }
 248         f = &qos->flags;
 249         list_for_each_entry_safe(req, tmp, &f->list, data.flr.node) {
 250                 apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
 251                 memset(req, 0, sizeof(*req));
 252         }
 253
 254         spin_lock_irq(&dev->power.lock);
 255         dev->power.qos = ERR_PTR(-ENODEV);
 256         spin_unlock_irq(&dev->power.lock);
 257
 258         kfree(c->notifiers);
 259         kfree(qos);
 260
 261  out:
 262         mutex_unlock(&dev_pm_qos_mtx);
 263
 264         mutex_unlock(&dev_pm_qos_sysfs_mtx);
 265 }
 266
 267 /**
 268  * dev_pm_qos_add_request - inserts new qos request into the list
 269  * @dev: target device for the constraint
 270  * @req: pointer to a preallocated handle
 271  * @type: type of the request
 272  * @value: defines the qos request
 273  *
 274  * This function inserts a new entry in the device constraints list of
 275  * requested qos performance characteristics. It recomputes the aggregate
 276  * QoS expectations of parameters and initializes the dev_pm_qos_request
 277  * handle.  Caller needs to save this handle for later use in updates and
 278  * removal.
 279  *
 280  * Returns 1 if the aggregated constraint value has changed,
 281  * 0 if the aggregated constraint value has not changed,
 282  * -EINVAL in case of wrong parameters, -ENOMEM if there's not enough memory
 283  * to allocate for data structures, -ENODEV if the device has just been removed
 284  * from the system.
 285  *
 286  * Callers should ensure that the target device is not RPM_SUSPENDED before
 287  * using this function for requests of type DEV_PM_QOS_FLAGS.
 288  */
 289 int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
 290                            enum dev_pm_qos_req_type type, s32 value)
 291 {
 292         int ret = 0;
 293
 294         if (!dev || !req) /*guard against callers passing in null */
 295                 return -EINVAL;
 296
 297         if (WARN(dev_pm_qos_request_active(req),
 298                  "%s() called for already added request\n", __func__))
 299                 return -EINVAL;
 300
 301         mutex_lock(&dev_pm_qos_mtx);
 302
 303         if (IS_ERR(dev->power.qos))
 304                 ret = -ENODEV;
 305         else if (!dev->power.qos)
 306                 ret = dev_pm_qos_constraints_allocate(dev);
 307
 308         if (!ret) {
 309                 req->dev = dev;
 310                 req->type = type;
 311                 ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
 312         }
 313
 314         mutex_unlock(&dev_pm_qos_mtx);
 315
 316         return ret;
 317 }
 318 EXPORT_SYMBOL_GPL(dev_pm_qos_add_request);
 319
 320 /**
 321  * __dev_pm_qos_update_request - Modify an existing device PM QoS request.
 322  * @req : PM QoS request to modify.
 323  * @new_value: New value to request.
 324  */
 325 static int __dev_pm_qos_update_request(struct dev_pm_qos_request *req,
 326                                        s32 new_value)
 327 {
 328         s32 curr_value;
 329         int ret = 0;
 330
 331         if (!req) /*guard against callers passing in null */
 332                 return -EINVAL;
 333
 334         if (WARN(!dev_pm_qos_request_active(req),
 335                  "%s() called for unknown object\n", __func__))
 336                 return -EINVAL;
 337
 338         if (IS_ERR_OR_NULL(req->dev->power.qos))
 339                 return -ENODEV;
 340
 341         switch(req->type) {
 342         case DEV_PM_QOS_LATENCY:
 343                 curr_value = req->data.pnode.prio;
 344                 break;
 345         case DEV_PM_QOS_FLAGS:
 346                 curr_value = req->data.flr.flags;
 347                 break;
 348         default:
 349                 return -EINVAL;
 350         }
 351
 352         if (curr_value != new_value)
 353                 ret = apply_constraint(req, PM_QOS_UPDATE_REQ, new_value);
 354
 355         return ret;
 356 }
 357
 358 /**
 359  * dev_pm_qos_update_request - modifies an existing qos request
 360  * @req : handle to list element holding a dev_pm_qos request to use
 361  * @new_value: defines the qos request
 362  *
 363  * Updates an existing dev PM qos request along with updating the
 364  * target value.
 365  *
 366  * Attempts are made to make this code callable on hot code paths.
 367  *
 368  * Returns 1 if the aggregated constraint value has changed,
 369  * 0 if the aggregated constraint value has not changed,
 370  * -EINVAL in case of wrong parameters, -ENODEV if the device has been
 371  * removed from the system
 372  *
 373  * Callers should ensure that the target device is not RPM_SUSPENDED before
 374  * using this function for requests of type DEV_PM_QOS_FLAGS.
 375  */
 376 int dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value)
 377 {
 378         int ret;
 379
 380         mutex_lock(&dev_pm_qos_mtx);
 381         ret = __dev_pm_qos_update_request(req, new_value);
 382         mutex_unlock(&dev_pm_qos_mtx);
 383         return ret;
 384 }
 385 EXPORT_SYMBOL_GPL(dev_pm_qos_update_request);
 386
 387 static int __dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
 388 {
 389         int ret;
 390
 391         if (!req) /*guard against callers passing in null */
 392                 return -EINVAL;
 393
 394         if (WARN(!dev_pm_qos_request_active(req),
 395                  "%s() called for unknown object\n", __func__))
 396                 return -EINVAL;
 397
 398         if (IS_ERR_OR_NULL(req->dev->power.qos))
 399                 return -ENODEV;
 400
 401         ret = apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
 402         memset(req, 0, sizeof(*req));
 403         return ret;
 404 }
 405
 406 /**
 407  * dev_pm_qos_remove_request - modifies an existing qos request
 408  * @req: handle to request list element
 409  *
 410  * Will remove pm qos request from the list of constraints and
 411  * recompute the current target value. Call this on slow code paths.
 412  *
 413  * Returns 1 if the aggregated constraint value has changed,
 414  * 0 if the aggregated constraint value has not changed,
 415  * -EINVAL in case of wrong parameters, -ENODEV if the device has been
 416  * removed from the system
 417  *
 418  * Callers should ensure that the target device is not RPM_SUSPENDED before
 419  * using this function for requests of type DEV_PM_QOS_FLAGS.
 420  */
 421 int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
 422 {
 423         int ret;
 424
 425         mutex_lock(&dev_pm_qos_mtx);
 426         ret = __dev_pm_qos_remove_request(req);
 427         mutex_unlock(&dev_pm_qos_mtx);
 428         return ret;
 429 }
 430 EXPORT_SYMBOL_GPL(dev_pm_qos_remove_request);
 431
 432 /**
 433  * dev_pm_qos_add_notifier - sets notification entry for changes to target value
 434  * of per-device PM QoS constraints
 435  *
 436  * @dev: target device for the constraint
 437  * @notifier: notifier block managed by caller.
 438  *
 439  * Will register the notifier into a notification chain that gets called
 440  * upon changes to the target value for the device.
 441  *
 442  * If the device's constraints object doesn't exist when this routine is called,
 443  * it will be created (or error code will be returned if that fails).
 444  */
 445 int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier)
 446 {
 447         int ret = 0;
 448
 449         mutex_lock(&dev_pm_qos_mtx);
 450
 451         if (IS_ERR(dev->power.qos))
 452                 ret = -ENODEV;
 453         else if (!dev->power.qos)
 454                 ret = dev_pm_qos_constraints_allocate(dev);
 455
 456         if (!ret)
 457                 ret = blocking_notifier_chain_register(
 458                                 dev->power.qos->latency.notifiers, notifier);
 459
 460         mutex_unlock(&dev_pm_qos_mtx);
 461         return ret;
 462 }
 463 EXPORT_SYMBOL_GPL(dev_pm_qos_add_notifier);
 464
 465 /**
 466  * dev_pm_qos_remove_notifier - deletes notification for changes to target value
 467  * of per-device PM QoS constraints
 468  *
 469  * @dev: target device for the constraint
 470  * @notifier: notifier block to be removed.
 471  *
 472  * Will remove the notifier from the notification chain that gets called
 473  * upon changes to the target value.
 474  */
 475 int dev_pm_qos_remove_notifier(struct device *dev,
 476                                struct notifier_block *notifier)
 477 {
 478         int retval = 0;
 479
 480         mutex_lock(&dev_pm_qos_mtx);
 481
 482         /* Silently return if the constraints object is not present. */
 483         if (!IS_ERR_OR_NULL(dev->power.qos))
 484                 retval = blocking_notifier_chain_unregister(
 485                                 dev->power.qos->latency.notifiers,
 486                                 notifier);
 487
 488         mutex_unlock(&dev_pm_qos_mtx);
 489         return retval;
 490 }
 491 EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier);
 492
 493 /**
 494  * dev_pm_qos_add_global_notifier - sets notification entry for changes to
 495  * target value of the PM QoS constraints for any device
 496  *
 497  * @notifier: notifier block managed by caller.
 498  *
 499  * Will register the notifier into a notification chain that gets called
 500  * upon changes to the target value for any device.
 501  */
 502 int dev_pm_qos_add_global_notifier(struct notifier_block *notifier)
 503 {
 504         return blocking_notifier_chain_register(&dev_pm_notifiers, notifier);
 505 }
 506 EXPORT_SYMBOL_GPL(dev_pm_qos_add_global_notifier);
 507
 508 /**
 509  * dev_pm_qos_remove_global_notifier - deletes notification for changes to
 510  * target value of PM QoS constraints for any device
 511  *
 512  * @notifier: notifier block to be removed.
 513  *
 514  * Will remove the notifier from the notification chain that gets called
 515  * upon changes to the target value for any device.
 516  */
 517 int dev_pm_qos_remove_global_notifier(struct notifier_block *notifier)
 518 {
 519         return blocking_notifier_chain_unregister(&dev_pm_notifiers, notifier);
 520 }
 521 EXPORT_SYMBOL_GPL(dev_pm_qos_remove_global_notifier);
 522
 523 /**
 524  * dev_pm_qos_add_ancestor_request - Add PM QoS request for device's ancestor.
 525  * @dev: Device whose ancestor to add the request for.
 526  * @req: Pointer to the preallocated handle.
 527  * @value: Constraint latency value.
 528  */
 529 int dev_pm_qos_add_ancestor_request(struct device *dev,
 530                                     struct dev_pm_qos_request *req, s32 value)
 531 {
 532         struct device *ancestor = dev->parent;
 533         int ret = -ENODEV;
 534
 535         while (ancestor && !ancestor->power.ignore_children)
 536                 ancestor = ancestor->parent;
 537
 538         if (ancestor)
 539                 ret = dev_pm_qos_add_request(ancestor, req,
 540                                              DEV_PM_QOS_LATENCY, value);
 541
 542         if (ret < 0)
 543                 req->dev = NULL;
 544
 545         return ret;
 546 }
 547 EXPORT_SYMBOL_GPL(dev_pm_qos_add_ancestor_request);
 548
 549 #ifdef CONFIG_PM_RUNTIME
 550 static void __dev_pm_qos_drop_user_request(struct device *dev,
 551                                            enum dev_pm_qos_req_type type)
 552 {
 553         struct dev_pm_qos_request *req = NULL;
 554
 555         switch(type) {
 556         case DEV_PM_QOS_LATENCY:
 557                 req = dev->power.qos->latency_req;
 558                 dev->power.qos->latency_req = NULL;
 559                 break;
 560         case DEV_PM_QOS_FLAGS:
 561                 req = dev->power.qos->flags_req;
 562                 dev->power.qos->flags_req = NULL;
 563                 break;
 564         }
 565         __dev_pm_qos_remove_request(req);
 566         kfree(req);
 567 }
 568
 569 static void dev_pm_qos_drop_user_request(struct device *dev,
 570                                          enum dev_pm_qos_req_type type)
 571 {
 572         mutex_lock(&dev_pm_qos_mtx);
 573         __dev_pm_qos_drop_user_request(dev, type);
 574         mutex_unlock(&dev_pm_qos_mtx);
 575 }
 576
 577 /**
 578  * dev_pm_qos_expose_latency_limit - Expose PM QoS latency limit to user space.
 579  * @dev: Device whose PM QoS latency limit is to be exposed to user space.
 580  * @value: Initial value of the latency limit.
 581  */
 582 int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value)
 583 {
 584         struct dev_pm_qos_request *req;
 585         int ret;
 586
 587         if (!device_is_registered(dev) || value < 0)
 588                 return -EINVAL;
 589
 590         req = kzalloc(sizeof(*req), GFP_KERNEL);
 591         if (!req)
 592                 return -ENOMEM;
 593
 594         ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY, value);
 595         if (ret < 0) {
 596                 kfree(req);
 597                 return ret;
 598         }
 599
 600         mutex_lock(&dev_pm_qos_sysfs_mtx);
 601
 602         mutex_lock(&dev_pm_qos_mtx);
 603
 604         if (IS_ERR_OR_NULL(dev->power.qos))
 605                 ret = -ENODEV;
 606         else if (dev->power.qos->latency_req)
 607                 ret = -EEXIST;
 608
 609         if (ret < 0) {
 610                 __dev_pm_qos_remove_request(req);
 611                 kfree(req);
 612                 mutex_unlock(&dev_pm_qos_mtx);
 613                 goto out;
 614         }
 615         dev->power.qos->latency_req = req;
 616
 617         mutex_unlock(&dev_pm_qos_mtx);
 618
 619         ret = pm_qos_sysfs_add_latency(dev);
 620         if (ret)
 621                 dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY);
 622
 623  out:
 624         mutex_unlock(&dev_pm_qos_sysfs_mtx);
 625         return ret;
 626 }
 627 EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_limit);
 628
 629 static void __dev_pm_qos_hide_latency_limit(struct device *dev)
 630 {
 631         if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->latency_req)
 632                 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY);
 633 }
 634
 635 /**
 636  * dev_pm_qos_hide_latency_limit - Hide PM QoS latency limit from user space.
 637  * @dev: Device whose PM QoS latency limit is to be hidden from user space.
 638  */
 639 void dev_pm_qos_hide_latency_limit(struct device *dev)
 640 {
 641         mutex_lock(&dev_pm_qos_sysfs_mtx);
 642
 643         pm_qos_sysfs_remove_latency(dev);
 644
 645         mutex_lock(&dev_pm_qos_mtx);
 646         __dev_pm_qos_hide_latency_limit(dev);
 647         mutex_unlock(&dev_pm_qos_mtx);
 648
 649         mutex_unlock(&dev_pm_qos_sysfs_mtx);
 650 }
 651 EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_limit);
 652
 653 /**
 654  * dev_pm_qos_expose_flags - Expose PM QoS flags of a device to user space.
 655  * @dev: Device whose PM QoS flags are to be exposed to user space.
 656  * @val: Initial values of the flags.
 657  */
 658 int dev_pm_qos_expose_flags(struct device *dev, s32 val)
 659 {
 660         struct dev_pm_qos_request *req;
 661         int ret;
 662
 663         if (!device_is_registered(dev))
 664                 return -EINVAL;
 665
 666         req = kzalloc(sizeof(*req), GFP_KERNEL);
 667         if (!req)
 668                 return -ENOMEM;
 669
 670         ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_FLAGS, val);
 671         if (ret < 0) {
 672                 kfree(req);
 673                 return ret;
 674         }
 675
 676         pm_runtime_get_sync(dev);
 677         mutex_lock(&dev_pm_qos_sysfs_mtx);
 678
 679         mutex_lock(&dev_pm_qos_mtx);
 680
 681         if (IS_ERR_OR_NULL(dev->power.qos))
 682                 ret = -ENODEV;
 683         else if (dev->power.qos->flags_req)
 684                 ret = -EEXIST;
 685
 686         if (ret < 0) {
 687                 __dev_pm_qos_remove_request(req);
 688                 kfree(req);
 689                 mutex_unlock(&dev_pm_qos_mtx);
 690                 goto out;
 691         }
 692         dev->power.qos->flags_req = req;
 693
 694         mutex_unlock(&dev_pm_qos_mtx);
 695
 696         ret = pm_qos_sysfs_add_flags(dev);
 697         if (ret)
 698                 dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS);
 699
 700  out:
 701         mutex_unlock(&dev_pm_qos_sysfs_mtx);
 702         pm_runtime_put(dev);
 703         return ret;
 704 }
 705 EXPORT_SYMBOL_GPL(dev_pm_qos_expose_flags);
 706
 707 static void __dev_pm_qos_hide_flags(struct device *dev)
 708 {
 709         if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->flags_req)
 710                 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_FLAGS);
 711 }
 712
 713 /**
 714  * dev_pm_qos_hide_flags - Hide PM QoS flags of a device from user space.
 715  * @dev: Device whose PM QoS flags are to be hidden from user space.
 716  */
 717 void dev_pm_qos_hide_flags(struct device *dev)
 718 {
 719         pm_runtime_get_sync(dev);
 720         mutex_lock(&dev_pm_qos_sysfs_mtx);
 721
 722         pm_qos_sysfs_remove_flags(dev);
 723
 724         mutex_lock(&dev_pm_qos_mtx);
 725         __dev_pm_qos_hide_flags(dev);
 726         mutex_unlock(&dev_pm_qos_mtx);
 727
 728         mutex_unlock(&dev_pm_qos_sysfs_mtx);
 729         pm_runtime_put(dev);
 730 }
 731 EXPORT_SYMBOL_GPL(dev_pm_qos_hide_flags);
 732
 733 /**
 734  * dev_pm_qos_update_flags - Update PM QoS flags request owned by user space.
 735  * @dev: Device to update the PM QoS flags request for.
 736  * @mask: Flags to set/clear.
 737  * @set: Whether to set or clear the flags (true means set).
 738  */
 739 int dev_pm_qos_update_flags(struct device *dev, s32 mask, bool set)
 740 {
 741         s32 value;
 742         int ret;
 743
 744         pm_runtime_get_sync(dev);
 745         mutex_lock(&dev_pm_qos_mtx);
 746
 747         if (IS_ERR_OR_NULL(dev->power.qos) || !dev->power.qos->flags_req) {
 748                 ret = -EINVAL;
 749                 goto out;
 750         }
 751
 752         value = dev_pm_qos_requested_flags(dev);
 753         if (set)
 754                 value |= mask;
 755         else
 756                 value &= ~mask;
 757
 758         ret = __dev_pm_qos_update_request(dev->power.qos->flags_req, value);
 759
 760  out:
 761         mutex_unlock(&dev_pm_qos_mtx);
 762         pm_runtime_put(dev);
 763         return ret;
 764 }
 765 #else /* !CONFIG_PM_RUNTIME */
 766 static void __dev_pm_qos_hide_latency_limit(struct device *dev) {}
 767 static void __dev_pm_qos_hide_flags(struct device *dev) {}
 768 #endif /* CONFIG_PM_RUNTIME */