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