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         usb_autopm_get_interface(intf);
 207         retval = usb_hub_set_port_power(hdev, hub, port1, true);
 208         msleep(hub_power_on_good_delay(hub));
 209         if (udev && !retval) {
 210                 /*
 211                  * Our preference is to simply wait for the port to reconnect,
 212                  * as that is the lowest latency method to restart the port.
 213                  * However, there are cases where toggling port power results in
 214                  * the host port and the device port getting out of sync causing
 215                  * a link training live lock.  Upon timeout, flag the port as
 216                  * needing warm reset recovery (to be performed later by
 217                  * usb_port_resume() as requested via usb_wakeup_notification())
 218                  */
 219                 if (hub_port_debounce_be_connected(hub, port1) < 0) {
 220                         dev_dbg(&port_dev->dev, "reconnect timeout\n");
 221                         if (hub_is_superspeed(hdev))
 222                                 set_bit(port1, hub->warm_reset_bits);
 223                 }
 224
 225                 /* Force the child awake to revalidate after the power loss. */
 226                 if (!test_and_set_bit(port1, hub->child_usage_bits)) {
 227                         pm_runtime_get_noresume(&port_dev->dev);
 228                         pm_request_resume(&udev->dev);
 229                 }
 230         }
 231
 232         usb_autopm_put_interface(intf);
 233
 234         return retval;
 235 }
 236
 237 static int usb_port_runtime_suspend(struct device *dev)
 238 {
 239         struct usb_port *port_dev = to_usb_port(dev);
 240         struct usb_device *hdev = to_usb_device(dev->parent->parent);
 241         struct usb_interface *intf = to_usb_interface(dev->parent);
 242         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
 243         struct usb_port *peer = port_dev->peer;
 244         int port1 = port_dev->portnum;
 245         int retval;
 246
 247         if (!hub)
 248                 return -EINVAL;
 249         if (hub->in_reset)
 250                 return -EBUSY;
 251
 252         if (dev_pm_qos_flags(&port_dev->dev, PM_QOS_FLAG_NO_POWER_OFF)
 253                         == PM_QOS_FLAGS_ALL)
 254                 return -EAGAIN;
 255
 256         if (usb_port_block_power_off)
 257                 return -EBUSY;
 258
 259         usb_autopm_get_interface(intf);
 260         retval = usb_hub_set_port_power(hdev, hub, port1, false);
 261         usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
 262         if (!port_dev->is_superspeed)
 263                 usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
 264         usb_autopm_put_interface(intf);
 265
 266         /*
 267          * Our peer usb3 port may now be able to suspend, so
 268          * asynchronously queue a suspend request to observe that this
 269          * usb2 port is now off.
 270          */
 271         if (!port_dev->is_superspeed && peer)
 272                 pm_runtime_put(&peer->dev);
 273
 274         return retval;
 275 }
 276 #endif
 277
 278 static const struct dev_pm_ops usb_port_pm_ops = {
 279 #ifdef CONFIG_PM
 280         .runtime_suspend =      usb_port_runtime_suspend,
 281         .runtime_resume =       usb_port_runtime_resume,
 282 #endif
 283 };
 284
 285 struct device_type usb_port_device_type = {
 286         .name =         "usb_port",
 287         .release =      usb_port_device_release,
 288         .pm =           &usb_port_pm_ops,
 289 };
 290
 291 static struct device_driver usb_port_driver = {
 292         .name = "usb",
 293         .owner = THIS_MODULE,
 294 };
 295
 296 static int link_peers(struct usb_port *left, struct usb_port *right)
 297 {
 298         struct usb_port *ss_port, *hs_port;
 299         int rc;
 300
 301         if (left->peer == right && right->peer == left)
 302                 return 0;
 303
 304         if (left->peer || right->peer) {
 305                 struct usb_port *lpeer = left->peer;
 306                 struct usb_port *rpeer = right->peer;
 307                 char *method;
 308
 309                 if (left->location && left->location == right->location)
 310                         method = "location";
 311                 else
 312                         method = "default";
 313
 314                 pr_debug("usb: failed to peer %s and %s by %s (%s:%s) (%s:%s)\n",
 315                         dev_name(&left->dev), dev_name(&right->dev), method,
 316                         dev_name(&left->dev),
 317                         lpeer ? dev_name(&lpeer->dev) : "none",
 318                         dev_name(&right->dev),
 319                         rpeer ? dev_name(&rpeer->dev) : "none");
 320                 return -EBUSY;
 321         }
 322
 323         rc = sysfs_create_link(&left->dev.kobj, &right->dev.kobj, "peer");
 324         if (rc)
 325                 return rc;
 326         rc = sysfs_create_link(&right->dev.kobj, &left->dev.kobj, "peer");
 327         if (rc) {
 328                 sysfs_remove_link(&left->dev.kobj, "peer");
 329                 return rc;
 330         }
 331
 332         /*
 333          * We need to wake the HiSpeed port to make sure we don't race
 334          * setting ->peer with usb_port_runtime_suspend().  Otherwise we
 335          * may miss a suspend event for the SuperSpeed port.
 336          */
 337         if (left->is_superspeed) {
 338                 ss_port = left;
 339                 WARN_ON(right->is_superspeed);
 340                 hs_port = right;
 341         } else {
 342                 ss_port = right;
 343                 WARN_ON(!right->is_superspeed);
 344                 hs_port = left;
 345         }
 346         pm_runtime_get_sync(&hs_port->dev);
 347
 348         left->peer = right;
 349         right->peer = left;
 350
 351         /*
 352          * The SuperSpeed reference is dropped when the HiSpeed port in
 353          * this relationship suspends, i.e. when it is safe to allow a
 354          * SuperSpeed connection to drop since there is no risk of a
 355          * device degrading to its powered-off HiSpeed connection.
 356          *
 357          * Also, drop the HiSpeed ref taken above.
 358          */
 359         pm_runtime_get_sync(&ss_port->dev);
 360         pm_runtime_put(&hs_port->dev);
 361
 362         return 0;
 363 }
 364
 365 static void link_peers_report(struct usb_port *left, struct usb_port *right)
 366 {
 367         int rc;
 368
 369         rc = link_peers(left, right);
 370         if (rc == 0) {
 371                 dev_dbg(&left->dev, "peered to %s\n", dev_name(&right->dev));
 372         } else {
 373                 dev_dbg(&left->dev, "failed to peer to %s (%d)\n",
 374                                 dev_name(&right->dev), rc);
 375                 pr_warn_once("usb: port power management may be unreliable\n");
 376                 usb_port_block_power_off = 1;
 377         }
 378 }
 379
 380 static void unlink_peers(struct usb_port *left, struct usb_port *right)
 381 {
 382         struct usb_port *ss_port, *hs_port;
 383
 384         WARN(right->peer != left || left->peer != right,
 385                         "%s and %s are not peers?\n",
 386                         dev_name(&left->dev), dev_name(&right->dev));
 387
 388         /*
 389          * We wake the HiSpeed port to make sure we don't race its
 390          * usb_port_runtime_resume() event which takes a SuperSpeed ref
 391          * when ->peer is !NULL.
 392          */
 393         if (left->is_superspeed) {
 394                 ss_port = left;
 395                 hs_port = right;
 396         } else {
 397                 ss_port = right;
 398                 hs_port = left;
 399         }
 400
 401         pm_runtime_get_sync(&hs_port->dev);
 402
 403         sysfs_remove_link(&left->dev.kobj, "peer");
 404         right->peer = NULL;
 405         sysfs_remove_link(&right->dev.kobj, "peer");
 406         left->peer = NULL;
 407
 408         /* Drop the SuperSpeed ref held on behalf of the active HiSpeed port */
 409         pm_runtime_put(&ss_port->dev);
 410
 411         /* Drop the ref taken above */
 412         pm_runtime_put(&hs_port->dev);
 413 }
 414
 415 /*
 416  * For each usb hub device in the system check to see if it is in the
 417  * peer domain of the given port_dev, and if it is check to see if it
 418  * has a port that matches the given port by location
 419  */
 420 static int match_location(struct usb_device *peer_hdev, void *p)
 421 {
 422         int port1;
 423         struct usb_hcd *hcd, *peer_hcd;
 424         struct usb_port *port_dev = p, *peer;
 425         struct usb_hub *peer_hub = usb_hub_to_struct_hub(peer_hdev);
 426         struct usb_device *hdev = to_usb_device(port_dev->dev.parent->parent);
 427
 428         if (!peer_hub)
 429                 return 0;
 430
 431         hcd = bus_to_hcd(hdev->bus);
 432         peer_hcd = bus_to_hcd(peer_hdev->bus);
 433         /* peer_hcd is provisional until we verify it against the known peer */
 434         if (peer_hcd != hcd->shared_hcd)
 435                 return 0;
 436
 437         for (port1 = 1; port1 <= peer_hdev->maxchild; port1++) {
 438                 peer = peer_hub->ports[port1 - 1];
 439                 if (peer && peer->location == port_dev->location) {
 440                         link_peers_report(port_dev, peer);
 441                         return 1; /* done */
 442                 }
 443         }
 444
 445         return 0;
 446 }
 447
 448 /*
 449  * Find the peer port either via explicit platform firmware "location"
 450  * data, the peer hcd for root hubs, or the upstream peer relationship
 451  * for all other hubs.
 452  */
 453 static void find_and_link_peer(struct usb_hub *hub, int port1)
 454 {
 455         struct usb_port *port_dev = hub->ports[port1 - 1], *peer;
 456         struct usb_device *hdev = hub->hdev;
 457         struct usb_device *peer_hdev;
 458         struct usb_hub *peer_hub;
 459
 460         /*
 461          * If location data is available then we can only peer this port
 462          * by a location match, not the default peer (lest we create a
 463          * situation where we need to go back and undo a default peering
 464          * when the port is later peered by location data)
 465          */
 466         if (port_dev->location) {
 467                 /* we link the peer in match_location() if found */
 468                 usb_for_each_dev(port_dev, match_location);
 469                 return;
 470         } else if (!hdev->parent) {
 471                 struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
 472                 struct usb_hcd *peer_hcd = hcd->shared_hcd;
 473
 474                 if (!peer_hcd)
 475                         return;
 476
 477                 peer_hdev = peer_hcd->self.root_hub;
 478         } else {
 479                 struct usb_port *upstream;
 480                 struct usb_device *parent = hdev->parent;
 481                 struct usb_hub *parent_hub = usb_hub_to_struct_hub(parent);
 482
 483                 if (!parent_hub)
 484                         return;
 485
 486                 upstream = parent_hub->ports[hdev->portnum - 1];
 487                 if (!upstream || !upstream->peer)
 488                         return;
 489
 490                 peer_hdev = upstream->peer->child;
 491         }
 492
 493         peer_hub = usb_hub_to_struct_hub(peer_hdev);
 494         if (!peer_hub || port1 > peer_hdev->maxchild)
 495                 return;
 496
 497         /*
 498          * we found a valid default peer, last check is to make sure it
 499          * does not have location data
 500          */
 501         peer = peer_hub->ports[port1 - 1];
 502         if (peer && peer->location == 0)
 503                 link_peers_report(port_dev, peer);
 504 }
 505
 506 int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 507 {
 508         struct usb_port *port_dev;
 509         struct usb_device *hdev = hub->hdev;
 510         int retval;
 511
 512         port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
 513         if (!port_dev)
 514                 return -ENOMEM;
 515
 516         port_dev->req = kzalloc(sizeof(*(port_dev->req)), GFP_KERNEL);
 517         if (!port_dev->req) {
 518                 kfree(port_dev);
 519                 return -ENOMEM;
 520         }
 521
 522         hub->ports[port1 - 1] = port_dev;
 523         port_dev->portnum = port1;
 524         set_bit(port1, hub->power_bits);
 525         port_dev->dev.parent = hub->intfdev;
 526         if (hub_is_superspeed(hdev)) {
 527                 port_dev->usb3_lpm_u1_permit = 1;
 528                 port_dev->usb3_lpm_u2_permit = 1;
 529                 port_dev->dev.groups = port_dev_usb3_group;
 530         } else
 531                 port_dev->dev.groups = port_dev_group;
 532         port_dev->dev.type = &usb_port_device_type;
 533         port_dev->dev.driver = &usb_port_driver;
 534         if (hub_is_superspeed(hub->hdev))
 535                 port_dev->is_superspeed = 1;
 536         dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),
 537                         port1);
 538         mutex_init(&port_dev->status_lock);
 539         retval = device_register(&port_dev->dev);
 540         if (retval) {
 541                 put_device(&port_dev->dev);
 542                 return retval;
 543         }
 544
 545         /* Set default policy of port-poweroff disabled. */
 546         retval = dev_pm_qos_add_request(&port_dev->dev, port_dev->req,
 547                         DEV_PM_QOS_FLAGS, PM_QOS_FLAG_NO_POWER_OFF);
 548         if (retval < 0) {
 549                 device_unregister(&port_dev->dev);
 550                 return retval;
 551         }
 552
 553         find_and_link_peer(hub, port1);
 554
 555         /*
 556          * Enable runtime pm and hold a refernce that hub_configure()
 557          * will drop once the PM_QOS_NO_POWER_OFF flag state has been set
 558          * and the hub has been fully registered (hdev->maxchild set).
 559          */
 560         pm_runtime_set_active(&port_dev->dev);
 561         pm_runtime_get_noresume(&port_dev->dev);
 562         pm_runtime_enable(&port_dev->dev);
 563         device_enable_async_suspend(&port_dev->dev);
 564
 565         /*
 566          * Keep hidden the ability to enable port-poweroff if the hub
 567          * does not support power switching.
 568          */
 569         if (!hub_is_port_power_switchable(hub))
 570                 return 0;
 571
 572         /* Attempt to let userspace take over the policy. */
 573         retval = dev_pm_qos_expose_flags(&port_dev->dev,
 574                         PM_QOS_FLAG_NO_POWER_OFF);
 575         if (retval < 0) {
 576                 dev_warn(&port_dev->dev, "failed to expose pm_qos_no_poweroff\n");
 577                 return 0;
 578         }
 579
 580         /* Userspace owns the policy, drop the kernel 'no_poweroff' request. */
 581         retval = dev_pm_qos_remove_request(port_dev->req);
 582         if (retval >= 0) {
 583                 kfree(port_dev->req);
 584                 port_dev->req = NULL;
 585         }
 586         return 0;
 587 }
 588
 589 void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
 590 {
 591         struct usb_port *port_dev = hub->ports[port1 - 1];
 592         struct usb_port *peer;
 593
 594         peer = port_dev->peer;
 595         if (peer)
 596                 unlink_peers(port_dev, peer);
 597         device_unregister(&port_dev->dev);
 598 }