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         retval = usb_autopm_get_interface(intf);
 217         if (retval < 0)
 218                 return retval;
 219
 220         retval = usb_hub_set_port_power(hdev, hub, port1, true);
 221         msleep(hub_power_on_good_delay(hub));
 222         if (udev && !retval) {
 223                 /*
 224                  * Our preference is to simply wait for the port to reconnect,
 225                  * as that is the lowest latency method to restart the port.
 226                  * However, there are cases where toggling port power results in
 227                  * the host port and the device port getting out of sync causing
 228                  * a link training live lock.  Upon timeout, flag the port as
 229                  * needing warm reset recovery (to be performed later by
 230                  * usb_port_resume() as requested via usb_wakeup_notification())
 231                  */
 232                 if (hub_port_debounce_be_connected(hub, port1) < 0) {
 233                         dev_dbg(&port_dev->dev, "reconnect timeout\n");
 234                         if (hub_is_superspeed(hdev))
 235                                 set_bit(port1, hub->warm_reset_bits);
 236                 }
 237
 238                 /* Force the child awake to revalidate after the power loss. */
 239                 if (!test_and_set_bit(port1, hub->child_usage_bits)) {
 240                         pm_runtime_get_noresume(&port_dev->dev);
 241                         pm_request_resume(&udev->dev);
 242                 }
 243         }
 244
 245         usb_autopm_put_interface(intf);
 246
 247         return retval;
 248 }
 249
 250 static int usb_port_runtime_suspend(struct device *dev)
 251 {
 252         struct usb_port *port_dev = to_usb_port(dev);
 253         struct usb_device *hdev = to_usb_device(dev->parent->parent);
 254         struct usb_interface *intf = to_usb_interface(dev->parent);
 255         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
 256         struct usb_port *peer = port_dev->peer;
 257         int port1 = port_dev->portnum;
 258         int retval;
 259
 260         if (!hub)
 261                 return -EINVAL;
 262         if (hub->in_reset)
 263                 return -EBUSY;
 264
 265         if (dev_pm_qos_flags(&port_dev->dev, PM_QOS_FLAG_NO_POWER_OFF)
 266                         == PM_QOS_FLAGS_ALL)
 267                 return -EAGAIN;
 268
 269         if (usb_port_block_power_off)
 270                 return -EBUSY;
 271
 272         retval = usb_autopm_get_interface(intf);
 273         if (retval < 0)
 274                 return retval;
 275
 276         retval = usb_hub_set_port_power(hdev, hub, port1, false);
 277         usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
 278         if (!port_dev->is_superspeed)
 279                 usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
 280         usb_autopm_put_interface(intf);
 281
 282         /*
 283          * Our peer usb3 port may now be able to suspend, so
 284          * asynchronously queue a suspend request to observe that this
 285          * usb2 port is now off.
 286          */
 287         if (!port_dev->is_superspeed && peer)
 288                 pm_runtime_put(&peer->dev);
 289
 290         return retval;
 291 }
 292 #endif
 293
 294 static void usb_port_shutdown(struct device *dev)
 295 {
 296         struct usb_port *port_dev = to_usb_port(dev);
 297
 298         if (port_dev->child) {
 299                 usb_disable_usb2_hardware_lpm(port_dev->child);
 300                 usb_unlocked_disable_lpm(port_dev->child);
 301         }
 302 }
 303
 304 static const struct dev_pm_ops usb_port_pm_ops = {
 305 #ifdef CONFIG_PM
 306         .runtime_suspend =      usb_port_runtime_suspend,
 307         .runtime_resume =       usb_port_runtime_resume,
 308 #endif
 309 };
 310
 311 struct device_type usb_port_device_type = {
 312         .name =         "usb_port",
 313         .release =      usb_port_device_release,
 314         .pm =           &usb_port_pm_ops,
 315 };
 316
 317 static struct device_driver usb_port_driver = {
 318         .name = "usb",
 319         .owner = THIS_MODULE,
 320         .shutdown = usb_port_shutdown,
 321 };
 322
 323 static int link_peers(struct usb_port *left, struct usb_port *right)
 324 {
 325         struct usb_port *ss_port, *hs_port;
 326         int rc;
 327
 328         if (left->peer == right && right->peer == left)
 329                 return 0;
 330
 331         if (left->peer || right->peer) {
 332                 struct usb_port *lpeer = left->peer;
 333                 struct usb_port *rpeer = right->peer;
 334                 char *method;
 335
 336                 if (left->location && left->location == right->location)
 337                         method = "location";
 338                 else
 339                         method = "default";
 340
 341                 pr_debug("usb: failed to peer %s and %s by %s (%s:%s) (%s:%s)\n",
 342                         dev_name(&left->dev), dev_name(&right->dev), method,
 343                         dev_name(&left->dev),
 344                         lpeer ? dev_name(&lpeer->dev) : "none",
 345                         dev_name(&right->dev),
 346                         rpeer ? dev_name(&rpeer->dev) : "none");
 347                 return -EBUSY;
 348         }
 349
 350         rc = sysfs_create_link(&left->dev.kobj, &right->dev.kobj, "peer");
 351         if (rc)
 352                 return rc;
 353         rc = sysfs_create_link(&right->dev.kobj, &left->dev.kobj, "peer");
 354         if (rc) {
 355                 sysfs_remove_link(&left->dev.kobj, "peer");
 356                 return rc;
 357         }
 358
 359         /*
 360          * We need to wake the HiSpeed port to make sure we don't race
 361          * setting ->peer with usb_port_runtime_suspend().  Otherwise we
 362          * may miss a suspend event for the SuperSpeed port.
 363          */
 364         if (left->is_superspeed) {
 365                 ss_port = left;
 366                 WARN_ON(right->is_superspeed);
 367                 hs_port = right;
 368         } else {
 369                 ss_port = right;
 370                 WARN_ON(!right->is_superspeed);
 371                 hs_port = left;
 372         }
 373         pm_runtime_get_sync(&hs_port->dev);
 374
 375         left->peer = right;
 376         right->peer = left;
 377
 378         /*
 379          * The SuperSpeed reference is dropped when the HiSpeed port in
 380          * this relationship suspends, i.e. when it is safe to allow a
 381          * SuperSpeed connection to drop since there is no risk of a
 382          * device degrading to its powered-off HiSpeed connection.
 383          *
 384          * Also, drop the HiSpeed ref taken above.
 385          */
 386         pm_runtime_get_sync(&ss_port->dev);
 387         pm_runtime_put(&hs_port->dev);
 388
 389         return 0;
 390 }
 391
 392 static void link_peers_report(struct usb_port *left, struct usb_port *right)
 393 {
 394         int rc;
 395
 396         rc = link_peers(left, right);
 397         if (rc == 0) {
 398                 dev_dbg(&left->dev, "peered to %s\n", dev_name(&right->dev));
 399         } else {
 400                 dev_dbg(&left->dev, "failed to peer to %s (%d)\n",
 401                                 dev_name(&right->dev), rc);
 402                 pr_warn_once("usb: port power management may be unreliable\n");
 403                 usb_port_block_power_off = 1;
 404         }
 405 }
 406
 407 static void unlink_peers(struct usb_port *left, struct usb_port *right)
 408 {
 409         struct usb_port *ss_port, *hs_port;
 410
 411         WARN(right->peer != left || left->peer != right,
 412                         "%s and %s are not peers?\n",
 413                         dev_name(&left->dev), dev_name(&right->dev));
 414
 415         /*
 416          * We wake the HiSpeed port to make sure we don't race its
 417          * usb_port_runtime_resume() event which takes a SuperSpeed ref
 418          * when ->peer is !NULL.
 419          */
 420         if (left->is_superspeed) {
 421                 ss_port = left;
 422                 hs_port = right;
 423         } else {
 424                 ss_port = right;
 425                 hs_port = left;
 426         }
 427
 428         pm_runtime_get_sync(&hs_port->dev);
 429
 430         sysfs_remove_link(&left->dev.kobj, "peer");
 431         right->peer = NULL;
 432         sysfs_remove_link(&right->dev.kobj, "peer");
 433         left->peer = NULL;
 434
 435         /* Drop the SuperSpeed ref held on behalf of the active HiSpeed port */
 436         pm_runtime_put(&ss_port->dev);
 437
 438         /* Drop the ref taken above */
 439         pm_runtime_put(&hs_port->dev);
 440 }
 441
 442 /*
 443  * For each usb hub device in the system check to see if it is in the
 444  * peer domain of the given port_dev, and if it is check to see if it
 445  * has a port that matches the given port by location
 446  */
 447 static int match_location(struct usb_device *peer_hdev, void *p)
 448 {
 449         int port1;
 450         struct usb_hcd *hcd, *peer_hcd;
 451         struct usb_port *port_dev = p, *peer;
 452         struct usb_hub *peer_hub = usb_hub_to_struct_hub(peer_hdev);
 453         struct usb_device *hdev = to_usb_device(port_dev->dev.parent->parent);
 454
 455         if (!peer_hub || port_dev->connect_type == USB_PORT_NOT_USED)
 456                 return 0;
 457
 458         hcd = bus_to_hcd(hdev->bus);
 459         peer_hcd = bus_to_hcd(peer_hdev->bus);
 460         /* peer_hcd is provisional until we verify it against the known peer */
 461         if (peer_hcd != hcd->shared_hcd)
 462                 return 0;
 463
 464         for (port1 = 1; port1 <= peer_hdev->maxchild; port1++) {
 465                 peer = peer_hub->ports[port1 - 1];
 466                 if (peer && peer->connect_type != USB_PORT_NOT_USED &&
 467                     peer->location == port_dev->location) {
 468                         link_peers_report(port_dev, peer);
 469                         return 1; /* done */
 470                 }
 471         }
 472
 473         return 0;
 474 }
 475
 476 /*
 477  * Find the peer port either via explicit platform firmware "location"
 478  * data, the peer hcd for root hubs, or the upstream peer relationship
 479  * for all other hubs.
 480  */
 481 static void find_and_link_peer(struct usb_hub *hub, int port1)
 482 {
 483         struct usb_port *port_dev = hub->ports[port1 - 1], *peer;
 484         struct usb_device *hdev = hub->hdev;
 485         struct usb_device *peer_hdev;
 486         struct usb_hub *peer_hub;
 487
 488         /*
 489          * If location data is available then we can only peer this port
 490          * by a location match, not the default peer (lest we create a
 491          * situation where we need to go back and undo a default peering
 492          * when the port is later peered by location data)
 493          */
 494         if (port_dev->location) {
 495                 /* we link the peer in match_location() if found */
 496                 usb_for_each_dev(port_dev, match_location);
 497                 return;
 498         } else if (!hdev->parent) {
 499                 struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
 500                 struct usb_hcd *peer_hcd = hcd->shared_hcd;
 501
 502                 if (!peer_hcd)
 503                         return;
 504
 505                 peer_hdev = peer_hcd->self.root_hub;
 506         } else {
 507                 struct usb_port *upstream;
 508                 struct usb_device *parent = hdev->parent;
 509                 struct usb_hub *parent_hub = usb_hub_to_struct_hub(parent);
 510
 511                 if (!parent_hub)
 512                         return;
 513
 514                 upstream = parent_hub->ports[hdev->portnum - 1];
 515                 if (!upstream || !upstream->peer)
 516                         return;
 517
 518                 peer_hdev = upstream->peer->child;
 519         }
 520
 521         peer_hub = usb_hub_to_struct_hub(peer_hdev);
 522         if (!peer_hub || port1 > peer_hdev->maxchild)
 523                 return;
 524
 525         /*
 526          * we found a valid default peer, last check is to make sure it
 527          * does not have location data
 528          */
 529         peer = peer_hub->ports[port1 - 1];
 530         if (peer && peer->location == 0)
 531                 link_peers_report(port_dev, peer);
 532 }
 533
 534 int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 535 {
 536         struct usb_port *port_dev;
 537         struct usb_device *hdev = hub->hdev;
 538         int retval;
 539
 540         port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
 541         if (!port_dev)
 542                 return -ENOMEM;
 543
 544         port_dev->req = kzalloc(sizeof(*(port_dev->req)), GFP_KERNEL);
 545         if (!port_dev->req) {
 546                 kfree(port_dev);
 547                 return -ENOMEM;
 548         }
 549
 550         hub->ports[port1 - 1] = port_dev;
 551         port_dev->portnum = port1;
 552         set_bit(port1, hub->power_bits);
 553         port_dev->dev.parent = hub->intfdev;
 554         if (hub_is_superspeed(hdev)) {
 555                 port_dev->usb3_lpm_u1_permit = 1;
 556                 port_dev->usb3_lpm_u2_permit = 1;
 557                 port_dev->dev.groups = port_dev_usb3_group;
 558         } else
 559                 port_dev->dev.groups = port_dev_group;
 560         port_dev->dev.type = &usb_port_device_type;
 561         port_dev->dev.driver = &usb_port_driver;
 562         if (hub_is_superspeed(hub->hdev))
 563                 port_dev->is_superspeed = 1;
 564         dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),
 565                         port1);
 566         mutex_init(&port_dev->status_lock);
 567         retval = device_register(&port_dev->dev);
 568         if (retval) {
 569                 put_device(&port_dev->dev);
 570                 return retval;
 571         }
 572
 573         /* Set default policy of port-poweroff disabled. */
 574         retval = dev_pm_qos_add_request(&port_dev->dev, port_dev->req,
 575                         DEV_PM_QOS_FLAGS, PM_QOS_FLAG_NO_POWER_OFF);
 576         if (retval < 0) {
 577                 device_unregister(&port_dev->dev);
 578                 return retval;
 579         }
 580
 581         find_and_link_peer(hub, port1);
 582
 583         /*
 584          * Enable runtime pm and hold a refernce that hub_configure()
 585          * will drop once the PM_QOS_NO_POWER_OFF flag state has been set
 586          * and the hub has been fully registered (hdev->maxchild set).
 587          */
 588         pm_runtime_set_active(&port_dev->dev);
 589         pm_runtime_get_noresume(&port_dev->dev);
 590         pm_runtime_enable(&port_dev->dev);
 591         device_enable_async_suspend(&port_dev->dev);
 592
 593         /*
 594          * Keep hidden the ability to enable port-poweroff if the hub
 595          * does not support power switching.
 596          */
 597         if (!hub_is_port_power_switchable(hub))
 598                 return 0;
 599
 600         /* Attempt to let userspace take over the policy. */
 601         retval = dev_pm_qos_expose_flags(&port_dev->dev,
 602                         PM_QOS_FLAG_NO_POWER_OFF);
 603         if (retval < 0) {
 604                 dev_warn(&port_dev->dev, "failed to expose pm_qos_no_poweroff\n");
 605                 return 0;
 606         }
 607
 608         /* Userspace owns the policy, drop the kernel 'no_poweroff' request. */
 609         retval = dev_pm_qos_remove_request(port_dev->req);
 610         if (retval >= 0) {
 611                 kfree(port_dev->req);
 612                 port_dev->req = NULL;
 613         }
 614         return 0;
 615 }
 616
 617 void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
 618 {
 619         struct usb_port *port_dev = hub->ports[port1 - 1];
 620         struct usb_port *peer;
 621
 622         peer = port_dev->peer;
 623         if (peer)
 624                 unlink_peers(port_dev, peer);
 625         device_unregister(&port_dev->dev);
 626 }