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