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