root/drivers/usb/core/port.c

DEFINITIONS

1. location_show
2. connect_type_show
3. over_current_count_show
4. quirks_show
5. quirks_store
6. usb3_lpm_permit_show
7. usb3_lpm_permit_store
8. usb_port_device_release
9. usb_port_runtime_resume
10. usb_port_runtime_suspend
11. usb_port_shutdown
12. link_peers
13. link_peers_report
14. unlink_peers
15. match_location
16. find_and_link_peer
17. usb_hub_create_port_device
18. usb_hub_remove_port_device

   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 }
 301 
 302 static const struct dev_pm_ops usb_port_pm_ops = {
 303 #ifdef CONFIG_PM
 304         .runtime_suspend =      usb_port_runtime_suspend,
 305         .runtime_resume =       usb_port_runtime_resume,
 306 #endif
 307 };
 308 
 309 struct device_type usb_port_device_type = {
 310         .name =         "usb_port",
 311         .release =      usb_port_device_release,
 312         .pm =           &usb_port_pm_ops,
 313 };
 314 
 315 static struct device_driver usb_port_driver = {
 316         .name = "usb",
 317         .owner = THIS_MODULE,
 318         .shutdown = usb_port_shutdown,
 319 };
 320 
 321 static int link_peers(struct usb_port *left, struct usb_port *right)
 322 {
 323         struct usb_port *ss_port, *hs_port;
 324         int rc;
 325 
 326         if (left->peer == right && right->peer == left)
 327                 return 0;
 328 
 329         if (left->peer || right->peer) {
 330                 struct usb_port *lpeer = left->peer;
 331                 struct usb_port *rpeer = right->peer;
 332                 char *method;
 333 
 334                 if (left->location && left->location == right->location)
 335                         method = "location";
 336                 else
 337                         method = "default";
 338 
 339                 pr_debug("usb: failed to peer %s and %s by %s (%s:%s) (%s:%s)\n",
 340                         dev_name(&left->dev), dev_name(&right->dev), method,
 341                         dev_name(&left->dev),
 342                         lpeer ? dev_name(&lpeer->dev) : "none",
 343                         dev_name(&right->dev),
 344                         rpeer ? dev_name(&rpeer->dev) : "none");
 345                 return -EBUSY;
 346         }
 347 
 348         rc = sysfs_create_link(&left->dev.kobj, &right->dev.kobj, "peer");
 349         if (rc)
 350                 return rc;
 351         rc = sysfs_create_link(&right->dev.kobj, &left->dev.kobj, "peer");
 352         if (rc) {
 353                 sysfs_remove_link(&left->dev.kobj, "peer");
 354                 return rc;
 355         }
 356 
 357         /*
 358          * We need to wake the HiSpeed port to make sure we don't race
 359          * setting ->peer with usb_port_runtime_suspend().  Otherwise we
 360          * may miss a suspend event for the SuperSpeed port.
 361          */
 362         if (left->is_superspeed) {
 363                 ss_port = left;
 364                 WARN_ON(right->is_superspeed);
 365                 hs_port = right;
 366         } else {
 367                 ss_port = right;
 368                 WARN_ON(!right->is_superspeed);
 369                 hs_port = left;
 370         }
 371         pm_runtime_get_sync(&hs_port->dev);
 372 
 373         left->peer = right;
 374         right->peer = left;
 375 
 376         /*
 377          * The SuperSpeed reference is dropped when the HiSpeed port in
 378          * this relationship suspends, i.e. when it is safe to allow a
 379          * SuperSpeed connection to drop since there is no risk of a
 380          * device degrading to its powered-off HiSpeed connection.
 381          *
 382          * Also, drop the HiSpeed ref taken above.
 383          */
 384         pm_runtime_get_sync(&ss_port->dev);
 385         pm_runtime_put(&hs_port->dev);
 386 
 387         return 0;
 388 }
 389 
 390 static void link_peers_report(struct usb_port *left, struct usb_port *right)
 391 {
 392         int rc;
 393 
 394         rc = link_peers(left, right);
 395         if (rc == 0) {
 396                 dev_dbg(&left->dev, "peered to %s\n", dev_name(&right->dev));
 397         } else {
 398                 dev_dbg(&left->dev, "failed to peer to %s (%d)\n",
 399                                 dev_name(&right->dev), rc);
 400                 pr_warn_once("usb: port power management may be unreliable\n");
 401                 usb_port_block_power_off = 1;
 402         }
 403 }
 404 
 405 static void unlink_peers(struct usb_port *left, struct usb_port *right)
 406 {
 407         struct usb_port *ss_port, *hs_port;
 408 
 409         WARN(right->peer != left || left->peer != right,
 410                         "%s and %s are not peers?\n",
 411                         dev_name(&left->dev), dev_name(&right->dev));
 412 
 413         /*
 414          * We wake the HiSpeed port to make sure we don't race its
 415          * usb_port_runtime_resume() event which takes a SuperSpeed ref
 416          * when ->peer is !NULL.
 417          */
 418         if (left->is_superspeed) {
 419                 ss_port = left;
 420                 hs_port = right;
 421         } else {
 422                 ss_port = right;
 423                 hs_port = left;
 424         }
 425 
 426         pm_runtime_get_sync(&hs_port->dev);
 427 
 428         sysfs_remove_link(&left->dev.kobj, "peer");
 429         right->peer = NULL;
 430         sysfs_remove_link(&right->dev.kobj, "peer");
 431         left->peer = NULL;
 432 
 433         /* Drop the SuperSpeed ref held on behalf of the active HiSpeed port */
 434         pm_runtime_put(&ss_port->dev);
 435 
 436         /* Drop the ref taken above */
 437         pm_runtime_put(&hs_port->dev);
 438 }
 439 
 440 /*
 441  * For each usb hub device in the system check to see if it is in the
 442  * peer domain of the given port_dev, and if it is check to see if it
 443  * has a port that matches the given port by location
 444  */
 445 static int match_location(struct usb_device *peer_hdev, void *p)
 446 {
 447         int port1;
 448         struct usb_hcd *hcd, *peer_hcd;
 449         struct usb_port *port_dev = p, *peer;
 450         struct usb_hub *peer_hub = usb_hub_to_struct_hub(peer_hdev);
 451         struct usb_device *hdev = to_usb_device(port_dev->dev.parent->parent);
 452 
 453         if (!peer_hub)
 454                 return 0;
 455 
 456         hcd = bus_to_hcd(hdev->bus);
 457         peer_hcd = bus_to_hcd(peer_hdev->bus);
 458         /* peer_hcd is provisional until we verify it against the known peer */
 459         if (peer_hcd != hcd->shared_hcd)
 460                 return 0;
 461 
 462         for (port1 = 1; port1 <= peer_hdev->maxchild; port1++) {
 463                 peer = peer_hub->ports[port1 - 1];
 464                 if (peer && peer->location == port_dev->location) {
 465                         link_peers_report(port_dev, peer);
 466                         return 1; /* done */
 467                 }
 468         }
 469 
 470         return 0;
 471 }
 472 
 473 /*
 474  * Find the peer port either via explicit platform firmware "location"
 475  * data, the peer hcd for root hubs, or the upstream peer relationship
 476  * for all other hubs.
 477  */
 478 static void find_and_link_peer(struct usb_hub *hub, int port1)
 479 {
 480         struct usb_port *port_dev = hub->ports[port1 - 1], *peer;
 481         struct usb_device *hdev = hub->hdev;
 482         struct usb_device *peer_hdev;
 483         struct usb_hub *peer_hub;
 484 
 485         /*
 486          * If location data is available then we can only peer this port
 487          * by a location match, not the default peer (lest we create a
 488          * situation where we need to go back and undo a default peering
 489          * when the port is later peered by location data)
 490          */
 491         if (port_dev->location) {
 492                 /* we link the peer in match_location() if found */
 493                 usb_for_each_dev(port_dev, match_location);
 494                 return;
 495         } else if (!hdev->parent) {
 496                 struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
 497                 struct usb_hcd *peer_hcd = hcd->shared_hcd;
 498 
 499                 if (!peer_hcd)
 500                         return;
 501 
 502                 peer_hdev = peer_hcd->self.root_hub;
 503         } else {
 504                 struct usb_port *upstream;
 505                 struct usb_device *parent = hdev->parent;
 506                 struct usb_hub *parent_hub = usb_hub_to_struct_hub(parent);
 507 
 508                 if (!parent_hub)
 509                         return;
 510 
 511                 upstream = parent_hub->ports[hdev->portnum - 1];
 512                 if (!upstream || !upstream->peer)
 513                         return;
 514 
 515                 peer_hdev = upstream->peer->child;
 516         }
 517 
 518         peer_hub = usb_hub_to_struct_hub(peer_hdev);
 519         if (!peer_hub || port1 > peer_hdev->maxchild)
 520                 return;
 521 
 522         /*
 523          * we found a valid default peer, last check is to make sure it
 524          * does not have location data
 525          */
 526         peer = peer_hub->ports[port1 - 1];
 527         if (peer && peer->location == 0)
 528                 link_peers_report(port_dev, peer);
 529 }
 530 
 531 int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 532 {
 533         struct usb_port *port_dev;
 534         struct usb_device *hdev = hub->hdev;
 535         int retval;
 536 
 537         port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
 538         if (!port_dev)
 539                 return -ENOMEM;
 540 
 541         port_dev->req = kzalloc(sizeof(*(port_dev->req)), GFP_KERNEL);
 542         if (!port_dev->req) {
 543                 kfree(port_dev);
 544                 return -ENOMEM;
 545         }
 546 
 547         hub->ports[port1 - 1] = port_dev;
 548         port_dev->portnum = port1;
 549         set_bit(port1, hub->power_bits);
 550         port_dev->dev.parent = hub->intfdev;
 551         if (hub_is_superspeed(hdev)) {
 552                 port_dev->usb3_lpm_u1_permit = 1;
 553                 port_dev->usb3_lpm_u2_permit = 1;
 554                 port_dev->dev.groups = port_dev_usb3_group;
 555         } else
 556                 port_dev->dev.groups = port_dev_group;
 557         port_dev->dev.type = &usb_port_device_type;
 558         port_dev->dev.driver = &usb_port_driver;
 559         if (hub_is_superspeed(hub->hdev))
 560                 port_dev->is_superspeed = 1;
 561         dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),
 562                         port1);
 563         mutex_init(&port_dev->status_lock);
 564         retval = device_register(&port_dev->dev);
 565         if (retval) {
 566                 put_device(&port_dev->dev);
 567                 return retval;
 568         }
 569 
 570         /* Set default policy of port-poweroff disabled. */
 571         retval = dev_pm_qos_add_request(&port_dev->dev, port_dev->req,
 572                         DEV_PM_QOS_FLAGS, PM_QOS_FLAG_NO_POWER_OFF);
 573         if (retval < 0) {
 574                 device_unregister(&port_dev->dev);
 575                 return retval;
 576         }
 577 
 578         find_and_link_peer(hub, port1);
 579 
 580         /*
 581          * Enable runtime pm and hold a refernce that hub_configure()
 582          * will drop once the PM_QOS_NO_POWER_OFF flag state has been set
 583          * and the hub has been fully registered (hdev->maxchild set).
 584          */
 585         pm_runtime_set_active(&port_dev->dev);
 586         pm_runtime_get_noresume(&port_dev->dev);
 587         pm_runtime_enable(&port_dev->dev);
 588         device_enable_async_suspend(&port_dev->dev);
 589 
 590         /*
 591          * Keep hidden the ability to enable port-poweroff if the hub
 592          * does not support power switching.
 593          */
 594         if (!hub_is_port_power_switchable(hub))
 595                 return 0;
 596 
 597         /* Attempt to let userspace take over the policy. */
 598         retval = dev_pm_qos_expose_flags(&port_dev->dev,
 599                         PM_QOS_FLAG_NO_POWER_OFF);
 600         if (retval < 0) {
 601                 dev_warn(&port_dev->dev, "failed to expose pm_qos_no_poweroff\n");
 602                 return 0;
 603         }
 604 
 605         /* Userspace owns the policy, drop the kernel 'no_poweroff' request. */
 606         retval = dev_pm_qos_remove_request(port_dev->req);
 607         if (retval >= 0) {
 608                 kfree(port_dev->req);
 609                 port_dev->req = NULL;
 610         }
 611         return 0;
 612 }
 613 
 614 void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
 615 {
 616         struct usb_port *port_dev = hub->ports[port1 - 1];
 617         struct usb_port *peer;
 618 
 619         peer = port_dev->peer;
 620         if (peer)
 621                 unlink_peers(port_dev, peer);
 622         device_unregister(&port_dev->dev);
 623 }