drivers/usb/core/port.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * usb port device code
   4  *
   5  * Copyright (C) 2012 Intel Corp
   6  *
   7  * Author: Lan Tianyu <[email protected]>
   8  */
   9
  10 #include <linux/slab.h>
  11 #include <linux/pm_qos.h>
  12 #include <linux/component.h>
  13
  14 #include "hub.h"
  15
  16 static int usb_port_block_power_off;
  17
  18 static const struct attribute_group *port_dev_group[];
  19
  20 static ssize_t disable_show(struct device *dev,
  21                               struct device_attribute *attr, char *buf)
  22 {
  23         struct usb_port *port_dev = to_usb_port(dev);
  24         struct usb_device *hdev = to_usb_device(dev->parent->parent);
  25         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
  26         struct usb_interface *intf = to_usb_interface(hub->intfdev);
  27         int port1 = port_dev->portnum;
  28         u16 portstatus, unused;
  29         bool disabled;
  30         int rc;
  31
  32         rc = usb_autopm_get_interface(intf);
  33         if (rc < 0)
  34                 return rc;
  35
  36         usb_lock_device(hdev);
  37         if (hub->disconnected) {
  38                 rc = -ENODEV;
  39                 goto out_hdev_lock;
  40         }
  41
  42         usb_hub_port_status(hub, port1, &portstatus, &unused);
  43         disabled = !usb_port_is_power_on(hub, portstatus);
  44
  45 out_hdev_lock:
  46         usb_unlock_device(hdev);
  47         usb_autopm_put_interface(intf);
  48
  49         if (rc)
  50                 return rc;
  51
  52         return sysfs_emit(buf, "%s\n", disabled ? "1" : "0");
  53 }
  54
  55 static ssize_t disable_store(struct device *dev, struct device_attribute *attr,
  56                             const char *buf, size_t count)
  57 {
  58         struct usb_port *port_dev = to_usb_port(dev);
  59         struct usb_device *hdev = to_usb_device(dev->parent->parent);
  60         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
  61         struct usb_interface *intf = to_usb_interface(hub->intfdev);
  62         int port1 = port_dev->portnum;
  63         bool disabled;
  64         int rc;
  65
  66         rc = strtobool(buf, &disabled);
  67         if (rc)
  68                 return rc;
  69
  70         rc = usb_autopm_get_interface(intf);
  71         if (rc < 0)
  72                 return rc;
  73
  74         usb_lock_device(hdev);
  75         if (hub->disconnected) {
  76                 rc = -ENODEV;
  77                 goto out_hdev_lock;
  78         }
  79
  80         if (disabled && port_dev->child)
  81                 usb_disconnect(&port_dev->child);
  82
  83         rc = usb_hub_set_port_power(hdev, hub, port1, !disabled);
  84
  85         if (disabled) {
  86                 usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
  87                 if (!port_dev->is_superspeed)
  88                         usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
  89         }
  90
  91         if (!rc)
  92                 rc = count;
  93
  94 out_hdev_lock:
  95         usb_unlock_device(hdev);
  96         usb_autopm_put_interface(intf);
  97
  98         return rc;
  99 }
 100 static DEVICE_ATTR_RW(disable);
 101
 102 static ssize_t location_show(struct device *dev,
 103                              struct device_attribute *attr, char *buf)
 104 {
 105         struct usb_port *port_dev = to_usb_port(dev);
 106
 107         return sprintf(buf, "0x%08x\n", port_dev->location);
 108 }
 109 static DEVICE_ATTR_RO(location);
 110
 111 static ssize_t connect_type_show(struct device *dev,
 112                                  struct device_attribute *attr, char *buf)
 113 {
 114         struct usb_port *port_dev = to_usb_port(dev);
 115         char *result;
 116
 117         switch (port_dev->connect_type) {
 118         case USB_PORT_CONNECT_TYPE_HOT_PLUG:
 119                 result = "hotplug";
 120                 break;
 121         case USB_PORT_CONNECT_TYPE_HARD_WIRED:
 122                 result = "hardwired";
 123                 break;
 124         case USB_PORT_NOT_USED:
 125                 result = "not used";
 126                 break;
 127         default:
 128                 result = "unknown";
 129                 break;
 130         }
 131
 132         return sprintf(buf, "%s\n", result);
 133 }
 134 static DEVICE_ATTR_RO(connect_type);
 135
 136 static ssize_t over_current_count_show(struct device *dev,
 137                                        struct device_attribute *attr, char *buf)
 138 {
 139         struct usb_port *port_dev = to_usb_port(dev);
 140
 141         return sprintf(buf, "%u\n", port_dev->over_current_count);
 142 }
 143 static DEVICE_ATTR_RO(over_current_count);
 144
 145 static ssize_t quirks_show(struct device *dev,
 146                            struct device_attribute *attr, char *buf)
 147 {
 148         struct usb_port *port_dev = to_usb_port(dev);
 149
 150         return sprintf(buf, "%08x\n", port_dev->quirks);
 151 }
 152
 153 static ssize_t quirks_store(struct device *dev, struct device_attribute *attr,
 154                             const char *buf, size_t count)
 155 {
 156         struct usb_port *port_dev = to_usb_port(dev);
 157         u32 value;
 158
 159         if (kstrtou32(buf, 16, &value))
 160                 return -EINVAL;
 161
 162         port_dev->quirks = value;
 163         return count;
 164 }
 165 static DEVICE_ATTR_RW(quirks);
 166
 167 static ssize_t usb3_lpm_permit_show(struct device *dev,
 168                               struct device_attribute *attr, char *buf)
 169 {
 170         struct usb_port *port_dev = to_usb_port(dev);
 171         const char *p;
 172
 173         if (port_dev->usb3_lpm_u1_permit) {
 174                 if (port_dev->usb3_lpm_u2_permit)
 175                         p = "u1_u2";
 176                 else
 177                         p = "u1";
 178         } else {
 179                 if (port_dev->usb3_lpm_u2_permit)
 180                         p = "u2";
 181                 else
 182                         p = "0";
 183         }
 184
 185         return sprintf(buf, "%s\n", p);
 186 }
 187
 188 static ssize_t usb3_lpm_permit_store(struct device *dev,
 189                                struct device_attribute *attr,
 190                                const char *buf, size_t count)
 191 {
 192         struct usb_port *port_dev = to_usb_port(dev);
 193         struct usb_device *udev = port_dev->child;
 194         struct usb_hcd *hcd;
 195
 196         if (!strncmp(buf, "u1_u2", 5)) {
 197                 port_dev->usb3_lpm_u1_permit = 1;
 198                 port_dev->usb3_lpm_u2_permit = 1;
 199
 200         } else if (!strncmp(buf, "u1", 2)) {
 201                 port_dev->usb3_lpm_u1_permit = 1;
 202                 port_dev->usb3_lpm_u2_permit = 0;
 203
 204         } else if (!strncmp(buf, "u2", 2)) {
 205                 port_dev->usb3_lpm_u1_permit = 0;
 206                 port_dev->usb3_lpm_u2_permit = 1;
 207
 208         } else if (!strncmp(buf, "0", 1)) {
 209                 port_dev->usb3_lpm_u1_permit = 0;
 210                 port_dev->usb3_lpm_u2_permit = 0;
 211         } else
 212                 return -EINVAL;
 213
 214         /* If device is connected to the port, disable or enable lpm
 215          * to make new u1 u2 setting take effect immediately.
 216          */
 217         if (udev) {
 218                 hcd = bus_to_hcd(udev->bus);
 219                 if (!hcd)
 220                         return -EINVAL;
 221                 usb_lock_device(udev);
 222                 mutex_lock(hcd->bandwidth_mutex);
 223                 if (!usb_disable_lpm(udev))
 224                         usb_enable_lpm(udev);
 225                 mutex_unlock(hcd->bandwidth_mutex);
 226                 usb_unlock_device(udev);
 227         }
 228
 229         return count;
 230 }
 231 static DEVICE_ATTR_RW(usb3_lpm_permit);
 232
 233 static struct attribute *port_dev_attrs[] = {
 234         &dev_attr_connect_type.attr,
 235         &dev_attr_location.attr,
 236         &dev_attr_quirks.attr,
 237         &dev_attr_over_current_count.attr,
 238         &dev_attr_disable.attr,
 239         NULL,
 240 };
 241
 242 static const struct attribute_group port_dev_attr_grp = {
 243         .attrs = port_dev_attrs,
 244 };
 245
 246 static const struct attribute_group *port_dev_group[] = {
 247         &port_dev_attr_grp,
 248         NULL,
 249 };
 250
 251 static struct attribute *port_dev_usb3_attrs[] = {
 252         &dev_attr_usb3_lpm_permit.attr,
 253         NULL,
 254 };
 255
 256 static const struct attribute_group port_dev_usb3_attr_grp = {
 257         .attrs = port_dev_usb3_attrs,
 258 };
 259
 260 static const struct attribute_group *port_dev_usb3_group[] = {
 261         &port_dev_attr_grp,
 262         &port_dev_usb3_attr_grp,
 263         NULL,
 264 };
 265
 266 static void usb_port_device_release(struct device *dev)
 267 {
 268         struct usb_port *port_dev = to_usb_port(dev);
 269
 270         kfree(port_dev->req);
 271         kfree(port_dev);
 272 }
 273
 274 #ifdef CONFIG_PM
 275 static int usb_port_runtime_resume(struct device *dev)
 276 {
 277         struct usb_port *port_dev = to_usb_port(dev);
 278         struct usb_device *hdev = to_usb_device(dev->parent->parent);
 279         struct usb_interface *intf = to_usb_interface(dev->parent);
 280         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
 281         struct usb_device *udev = port_dev->child;
 282         struct usb_port *peer = port_dev->peer;
 283         int port1 = port_dev->portnum;
 284         int retval;
 285
 286         if (!hub)
 287                 return -EINVAL;
 288         if (hub->in_reset) {
 289                 set_bit(port1, hub->power_bits);
 290                 return 0;
 291         }
 292
 293         /*
 294          * Power on our usb3 peer before this usb2 port to prevent a usb3
 295          * device from degrading to its usb2 connection
 296          */
 297         if (!port_dev->is_superspeed && peer)
 298                 pm_runtime_get_sync(&peer->dev);
 299
 300         retval = usb_autopm_get_interface(intf);
 301         if (retval < 0)
 302                 return retval;
 303
 304         retval = usb_hub_set_port_power(hdev, hub, port1, true);
 305         msleep(hub_power_on_good_delay(hub));
 306         if (udev && !retval) {
 307                 /*
 308                  * Our preference is to simply wait for the port to reconnect,
 309                  * as that is the lowest latency method to restart the port.
 310                  * However, there are cases where toggling port power results in
 311                  * the host port and the device port getting out of sync causing
 312                  * a link training live lock.  Upon timeout, flag the port as
 313                  * needing warm reset recovery (to be performed later by
 314                  * usb_port_resume() as requested via usb_wakeup_notification())
 315                  */
 316                 if (hub_port_debounce_be_connected(hub, port1) < 0) {
 317                         dev_dbg(&port_dev->dev, "reconnect timeout\n");
 318                         if (hub_is_superspeed(hdev))
 319                                 set_bit(port1, hub->warm_reset_bits);
 320                 }
 321
 322                 /* Force the child awake to revalidate after the power loss. */
 323                 if (!test_and_set_bit(port1, hub->child_usage_bits)) {
 324                         pm_runtime_get_noresume(&port_dev->dev);
 325                         pm_request_resume(&udev->dev);
 326                 }
 327         }
 328
 329         usb_autopm_put_interface(intf);
 330
 331         return retval;
 332 }
 333
 334 static int usb_port_runtime_suspend(struct device *dev)
 335 {
 336         struct usb_port *port_dev = to_usb_port(dev);
 337         struct usb_device *hdev = to_usb_device(dev->parent->parent);
 338         struct usb_interface *intf = to_usb_interface(dev->parent);
 339         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
 340         struct usb_port *peer = port_dev->peer;
 341         int port1 = port_dev->portnum;
 342         int retval;
 343
 344         if (!hub)
 345                 return -EINVAL;
 346         if (hub->in_reset)
 347                 return -EBUSY;
 348
 349         if (dev_pm_qos_flags(&port_dev->dev, PM_QOS_FLAG_NO_POWER_OFF)
 350                         == PM_QOS_FLAGS_ALL)
 351                 return -EAGAIN;
 352
 353         if (usb_port_block_power_off)
 354                 return -EBUSY;
 355
 356         retval = usb_autopm_get_interface(intf);
 357         if (retval < 0)
 358                 return retval;
 359
 360         retval = usb_hub_set_port_power(hdev, hub, port1, false);
 361         usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
 362         if (!port_dev->is_superspeed)
 363                 usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
 364         usb_autopm_put_interface(intf);
 365
 366         /*
 367          * Our peer usb3 port may now be able to suspend, so
 368          * asynchronously queue a suspend request to observe that this
 369          * usb2 port is now off.
 370          */
 371         if (!port_dev->is_superspeed && peer)
 372                 pm_runtime_put(&peer->dev);
 373
 374         return retval;
 375 }
 376 #endif
 377
 378 static void usb_port_shutdown(struct device *dev)
 379 {
 380         struct usb_port *port_dev = to_usb_port(dev);
 381
 382         if (port_dev->child)
 383                 usb_disable_usb2_hardware_lpm(port_dev->child);
 384 }
 385
 386 static const struct dev_pm_ops usb_port_pm_ops = {
 387 #ifdef CONFIG_PM
 388         .runtime_suspend =      usb_port_runtime_suspend,
 389         .runtime_resume =       usb_port_runtime_resume,
 390 #endif
 391 };
 392
 393 struct device_type usb_port_device_type = {
 394         .name =         "usb_port",
 395         .release =      usb_port_device_release,
 396         .pm =           &usb_port_pm_ops,
 397 };
 398
 399 static struct device_driver usb_port_driver = {
 400         .name = "usb",
 401         .owner = THIS_MODULE,
 402         .shutdown = usb_port_shutdown,
 403 };
 404
 405 static int link_peers(struct usb_port *left, struct usb_port *right)
 406 {
 407         struct usb_port *ss_port, *hs_port;
 408         int rc;
 409
 410         if (left->peer == right && right->peer == left)
 411                 return 0;
 412
 413         if (left->peer || right->peer) {
 414                 struct usb_port *lpeer = left->peer;
 415                 struct usb_port *rpeer = right->peer;
 416                 char *method;
 417
 418                 if (left->location && left->location == right->location)
 419                         method = "location";
 420                 else
 421                         method = "default";
 422
 423                 pr_debug("usb: failed to peer %s and %s by %s (%s:%s) (%s:%s)\n",
 424                         dev_name(&left->dev), dev_name(&right->dev), method,
 425                         dev_name(&left->dev),
 426                         lpeer ? dev_name(&lpeer->dev) : "none",
 427                         dev_name(&right->dev),
 428                         rpeer ? dev_name(&rpeer->dev) : "none");
 429                 return -EBUSY;
 430         }
 431
 432         rc = sysfs_create_link(&left->dev.kobj, &right->dev.kobj, "peer");
 433         if (rc)
 434                 return rc;
 435         rc = sysfs_create_link(&right->dev.kobj, &left->dev.kobj, "peer");
 436         if (rc) {
 437                 sysfs_remove_link(&left->dev.kobj, "peer");
 438                 return rc;
 439         }
 440
 441         /*
 442          * We need to wake the HiSpeed port to make sure we don't race
 443          * setting ->peer with usb_port_runtime_suspend().  Otherwise we
 444          * may miss a suspend event for the SuperSpeed port.
 445          */
 446         if (left->is_superspeed) {
 447                 ss_port = left;
 448                 WARN_ON(right->is_superspeed);
 449                 hs_port = right;
 450         } else {
 451                 ss_port = right;
 452                 WARN_ON(!right->is_superspeed);
 453                 hs_port = left;
 454         }
 455         pm_runtime_get_sync(&hs_port->dev);
 456
 457         left->peer = right;
 458         right->peer = left;
 459
 460         /*
 461          * The SuperSpeed reference is dropped when the HiSpeed port in
 462          * this relationship suspends, i.e. when it is safe to allow a
 463          * SuperSpeed connection to drop since there is no risk of a
 464          * device degrading to its powered-off HiSpeed connection.
 465          *
 466          * Also, drop the HiSpeed ref taken above.
 467          */
 468         pm_runtime_get_sync(&ss_port->dev);
 469         pm_runtime_put(&hs_port->dev);
 470
 471         return 0;
 472 }
 473
 474 static void link_peers_report(struct usb_port *left, struct usb_port *right)
 475 {
 476         int rc;
 477
 478         rc = link_peers(left, right);
 479         if (rc == 0) {
 480                 dev_dbg(&left->dev, "peered to %s\n", dev_name(&right->dev));
 481         } else {
 482                 dev_dbg(&left->dev, "failed to peer to %s (%d)\n",
 483                                 dev_name(&right->dev), rc);
 484                 pr_warn_once("usb: port power management may be unreliable\n");
 485                 usb_port_block_power_off = 1;
 486         }
 487 }
 488
 489 static void unlink_peers(struct usb_port *left, struct usb_port *right)
 490 {
 491         struct usb_port *ss_port, *hs_port;
 492
 493         WARN(right->peer != left || left->peer != right,
 494                         "%s and %s are not peers?\n",
 495                         dev_name(&left->dev), dev_name(&right->dev));
 496
 497         /*
 498          * We wake the HiSpeed port to make sure we don't race its
 499          * usb_port_runtime_resume() event which takes a SuperSpeed ref
 500          * when ->peer is !NULL.
 501          */
 502         if (left->is_superspeed) {
 503                 ss_port = left;
 504                 hs_port = right;
 505         } else {
 506                 ss_port = right;
 507                 hs_port = left;
 508         }
 509
 510         pm_runtime_get_sync(&hs_port->dev);
 511
 512         sysfs_remove_link(&left->dev.kobj, "peer");
 513         right->peer = NULL;
 514         sysfs_remove_link(&right->dev.kobj, "peer");
 515         left->peer = NULL;
 516
 517         /* Drop the SuperSpeed ref held on behalf of the active HiSpeed port */
 518         pm_runtime_put(&ss_port->dev);
 519
 520         /* Drop the ref taken above */
 521         pm_runtime_put(&hs_port->dev);
 522 }
 523
 524 /*
 525  * For each usb hub device in the system check to see if it is in the
 526  * peer domain of the given port_dev, and if it is check to see if it
 527  * has a port that matches the given port by location
 528  */
 529 static int match_location(struct usb_device *peer_hdev, void *p)
 530 {
 531         int port1;
 532         struct usb_hcd *hcd, *peer_hcd;
 533         struct usb_port *port_dev = p, *peer;
 534         struct usb_hub *peer_hub = usb_hub_to_struct_hub(peer_hdev);
 535         struct usb_device *hdev = to_usb_device(port_dev->dev.parent->parent);
 536
 537         if (!peer_hub)
 538                 return 0;
 539
 540         hcd = bus_to_hcd(hdev->bus);
 541         peer_hcd = bus_to_hcd(peer_hdev->bus);
 542         /* peer_hcd is provisional until we verify it against the known peer */
 543         if (peer_hcd != hcd->shared_hcd)
 544                 return 0;
 545
 546         for (port1 = 1; port1 <= peer_hdev->maxchild; port1++) {
 547                 peer = peer_hub->ports[port1 - 1];
 548                 if (peer && peer->location == port_dev->location) {
 549                         link_peers_report(port_dev, peer);
 550                         return 1; /* done */
 551                 }
 552         }
 553
 554         return 0;
 555 }
 556
 557 /*
 558  * Find the peer port either via explicit platform firmware "location"
 559  * data, the peer hcd for root hubs, or the upstream peer relationship
 560  * for all other hubs.
 561  */
 562 static void find_and_link_peer(struct usb_hub *hub, int port1)
 563 {
 564         struct usb_port *port_dev = hub->ports[port1 - 1], *peer;
 565         struct usb_device *hdev = hub->hdev;
 566         struct usb_device *peer_hdev;
 567         struct usb_hub *peer_hub;
 568
 569         /*
 570          * If location data is available then we can only peer this port
 571          * by a location match, not the default peer (lest we create a
 572          * situation where we need to go back and undo a default peering
 573          * when the port is later peered by location data)
 574          */
 575         if (port_dev->location) {
 576                 /* we link the peer in match_location() if found */
 577                 usb_for_each_dev(port_dev, match_location);
 578                 return;
 579         } else if (!hdev->parent) {
 580                 struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
 581                 struct usb_hcd *peer_hcd = hcd->shared_hcd;
 582
 583                 if (!peer_hcd)
 584                         return;
 585
 586                 peer_hdev = peer_hcd->self.root_hub;
 587         } else {
 588                 struct usb_port *upstream;
 589                 struct usb_device *parent = hdev->parent;
 590                 struct usb_hub *parent_hub = usb_hub_to_struct_hub(parent);
 591
 592                 if (!parent_hub)
 593                         return;
 594
 595                 upstream = parent_hub->ports[hdev->portnum - 1];
 596                 if (!upstream || !upstream->peer)
 597                         return;
 598
 599                 peer_hdev = upstream->peer->child;
 600         }
 601
 602         peer_hub = usb_hub_to_struct_hub(peer_hdev);
 603         if (!peer_hub || port1 > peer_hdev->maxchild)
 604                 return;
 605
 606         /*
 607          * we found a valid default peer, last check is to make sure it
 608          * does not have location data
 609          */
 610         peer = peer_hub->ports[port1 - 1];
 611         if (peer && peer->location == 0)
 612                 link_peers_report(port_dev, peer);
 613 }
 614
 615 static int connector_bind(struct device *dev, struct device *connector, void *data)
 616 {
 617         int ret;
 618
 619         ret = sysfs_create_link(&dev->kobj, &connector->kobj, "connector");
 620         if (ret)
 621                 return ret;
 622
 623         ret = sysfs_create_link(&connector->kobj, &dev->kobj, dev_name(dev));
 624         if (ret)
 625                 sysfs_remove_link(&dev->kobj, "connector");
 626
 627         return ret;
 628 }
 629
 630 static void connector_unbind(struct device *dev, struct device *connector, void *data)
 631 {
 632         sysfs_remove_link(&connector->kobj, dev_name(dev));
 633         sysfs_remove_link(&dev->kobj, "connector");
 634 }
 635
 636 static const struct component_ops connector_ops = {
 637         .bind = connector_bind,
 638         .unbind = connector_unbind,
 639 };
 640
 641 int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 642 {
 643         struct usb_port *port_dev;
 644         struct usb_device *hdev = hub->hdev;
 645         int retval;
 646
 647         port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
 648         if (!port_dev)
 649                 return -ENOMEM;
 650
 651         port_dev->req = kzalloc(sizeof(*(port_dev->req)), GFP_KERNEL);
 652         if (!port_dev->req) {
 653                 kfree(port_dev);
 654                 return -ENOMEM;
 655         }
 656
 657         hub->ports[port1 - 1] = port_dev;
 658         port_dev->portnum = port1;
 659         set_bit(port1, hub->power_bits);
 660         port_dev->dev.parent = hub->intfdev;
 661         if (hub_is_superspeed(hdev)) {
 662                 port_dev->usb3_lpm_u1_permit = 1;
 663                 port_dev->usb3_lpm_u2_permit = 1;
 664                 port_dev->dev.groups = port_dev_usb3_group;
 665         } else
 666                 port_dev->dev.groups = port_dev_group;
 667         port_dev->dev.type = &usb_port_device_type;
 668         port_dev->dev.driver = &usb_port_driver;
 669         if (hub_is_superspeed(hub->hdev))
 670                 port_dev->is_superspeed = 1;
 671         dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),
 672                         port1);
 673         mutex_init(&port_dev->status_lock);
 674         retval = device_register(&port_dev->dev);
 675         if (retval) {
 676                 put_device(&port_dev->dev);
 677                 return retval;
 678         }
 679
 680         /* Set default policy of port-poweroff disabled. */
 681         retval = dev_pm_qos_add_request(&port_dev->dev, port_dev->req,
 682                         DEV_PM_QOS_FLAGS, PM_QOS_FLAG_NO_POWER_OFF);
 683         if (retval < 0) {
 684                 device_unregister(&port_dev->dev);
 685                 return retval;
 686         }
 687
 688         retval = component_add(&port_dev->dev, &connector_ops);
 689         if (retval) {
 690                 dev_warn(&port_dev->dev, "failed to add component\n");
 691                 device_unregister(&port_dev->dev);
 692                 return retval;
 693         }
 694
 695         find_and_link_peer(hub, port1);
 696
 697         /*
 698          * Enable runtime pm and hold a refernce that hub_configure()
 699          * will drop once the PM_QOS_NO_POWER_OFF flag state has been set
 700          * and the hub has been fully registered (hdev->maxchild set).
 701          */
 702         pm_runtime_set_active(&port_dev->dev);
 703         pm_runtime_get_noresume(&port_dev->dev);
 704         pm_runtime_enable(&port_dev->dev);
 705         device_enable_async_suspend(&port_dev->dev);
 706
 707         /*
 708          * Keep hidden the ability to enable port-poweroff if the hub
 709          * does not support power switching.
 710          */
 711         if (!hub_is_port_power_switchable(hub))
 712                 return 0;
 713
 714         /* Attempt to let userspace take over the policy. */
 715         retval = dev_pm_qos_expose_flags(&port_dev->dev,
 716                         PM_QOS_FLAG_NO_POWER_OFF);
 717         if (retval < 0) {
 718                 dev_warn(&port_dev->dev, "failed to expose pm_qos_no_poweroff\n");
 719                 return 0;
 720         }
 721
 722         /* Userspace owns the policy, drop the kernel 'no_poweroff' request. */
 723         retval = dev_pm_qos_remove_request(port_dev->req);
 724         if (retval >= 0) {
 725                 kfree(port_dev->req);
 726                 port_dev->req = NULL;
 727         }
 728         return 0;
 729 }
 730
 731 void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
 732 {
 733         struct usb_port *port_dev = hub->ports[port1 - 1];
 734         struct usb_port *peer;
 735
 736         peer = port_dev->peer;
 737         if (peer)
 738                 unlink_peers(port_dev, peer);
 739         component_del(&port_dev->dev, &connector_ops);
 740         device_unregister(&port_dev->dev);
 741 }