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 usb3_lpm_permit_show(struct device *dev,
  45                               struct device_attribute *attr, char *buf)
  46 {
  47         struct usb_port *port_dev = to_usb_port(dev);
  48         const char *p;
  49
  50         if (port_dev->usb3_lpm_u1_permit) {
  51                 if (port_dev->usb3_lpm_u2_permit)
  52                         p = "u1_u2";
  53                 else
  54                         p = "u1";
  55         } else {
  56                 if (port_dev->usb3_lpm_u2_permit)
  57                         p = "u2";
  58                 else
  59                         p = "0";
  60         }
  61
  62         return sprintf(buf, "%s\n", p);
  63 }
  64
  65 static ssize_t usb3_lpm_permit_store(struct device *dev,
  66                                struct device_attribute *attr,
  67                                const char *buf, size_t count)
  68 {
  69         struct usb_port *port_dev = to_usb_port(dev);
  70         struct usb_device *udev = port_dev->child;
  71         struct usb_hcd *hcd;
  72
  73         if (!strncmp(buf, "u1_u2", 5)) {
  74                 port_dev->usb3_lpm_u1_permit = 1;
  75                 port_dev->usb3_lpm_u2_permit = 1;
  76
  77         } else if (!strncmp(buf, "u1", 2)) {
  78                 port_dev->usb3_lpm_u1_permit = 1;
  79                 port_dev->usb3_lpm_u2_permit = 0;
  80
  81         } else if (!strncmp(buf, "u2", 2)) {
  82                 port_dev->usb3_lpm_u1_permit = 0;
  83                 port_dev->usb3_lpm_u2_permit = 1;
  84
  85         } else if (!strncmp(buf, "0", 1)) {
  86                 port_dev->usb3_lpm_u1_permit = 0;
  87                 port_dev->usb3_lpm_u2_permit = 0;
  88         } else
  89                 return -EINVAL;
  90
  91         /* If device is connected to the port, disable or enable lpm
  92          * to make new u1 u2 setting take effect immediately.
  93          */
  94         if (udev) {
  95                 hcd = bus_to_hcd(udev->bus);
  96                 if (!hcd)
  97                         return -EINVAL;
  98                 usb_lock_device(udev);
  99                 mutex_lock(hcd->bandwidth_mutex);
 100                 if (!usb_disable_lpm(udev))
 101                         usb_enable_lpm(udev);
 102                 mutex_unlock(hcd->bandwidth_mutex);
 103                 usb_unlock_device(udev);
 104         }
 105
 106         return count;
 107 }
 108 static DEVICE_ATTR_RW(usb3_lpm_permit);
 109
 110 static struct attribute *port_dev_attrs[] = {
 111         &dev_attr_connect_type.attr,
 112         NULL,
 113 };
 114
 115 static struct attribute_group port_dev_attr_grp = {
 116         .attrs = port_dev_attrs,
 117 };
 118
 119 static const struct attribute_group *port_dev_group[] = {
 120         &port_dev_attr_grp,
 121         NULL,
 122 };
 123
 124 static struct attribute *port_dev_usb3_attrs[] = {
 125         &dev_attr_usb3_lpm_permit.attr,
 126         NULL,
 127 };
 128
 129 static struct attribute_group port_dev_usb3_attr_grp = {
 130         .attrs = port_dev_usb3_attrs,
 131 };
 132
 133 static const struct attribute_group *port_dev_usb3_group[] = {
 134         &port_dev_attr_grp,
 135         &port_dev_usb3_attr_grp,
 136         NULL,
 137 };
 138
 139 static void usb_port_device_release(struct device *dev)
 140 {
 141         struct usb_port *port_dev = to_usb_port(dev);
 142
 143         kfree(port_dev->req);
 144         kfree(port_dev);
 145 }
 146
 147 #ifdef CONFIG_PM
 148 static int usb_port_runtime_resume(struct device *dev)
 149 {
 150         struct usb_port *port_dev = to_usb_port(dev);
 151         struct usb_device *hdev = to_usb_device(dev->parent->parent);
 152         struct usb_interface *intf = to_usb_interface(dev->parent);
 153         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
 154         struct usb_device *udev = port_dev->child;
 155         struct usb_port *peer = port_dev->peer;
 156         int port1 = port_dev->portnum;
 157         int retval;
 158
 159         if (!hub)
 160                 return -EINVAL;
 161         if (hub->in_reset) {
 162                 set_bit(port1, hub->power_bits);
 163                 return 0;
 164         }
 165
 166         /*
 167          * Power on our usb3 peer before this usb2 port to prevent a usb3
 168          * device from degrading to its usb2 connection
 169          */
 170         if (!port_dev->is_superspeed && peer)
 171                 pm_runtime_get_sync(&peer->dev);
 172
 173         usb_autopm_get_interface(intf);
 174         retval = usb_hub_set_port_power(hdev, hub, port1, true);
 175         msleep(hub_power_on_good_delay(hub));
 176         if (udev && !retval) {
 177                 /*
 178                  * Our preference is to simply wait for the port to reconnect,
 179                  * as that is the lowest latency method to restart the port.
 180                  * However, there are cases where toggling port power results in
 181                  * the host port and the device port getting out of sync causing
 182                  * a link training live lock.  Upon timeout, flag the port as
 183                  * needing warm reset recovery (to be performed later by
 184                  * usb_port_resume() as requested via usb_wakeup_notification())
 185                  */
 186                 if (hub_port_debounce_be_connected(hub, port1) < 0) {
 187                         dev_dbg(&port_dev->dev, "reconnect timeout\n");
 188                         if (hub_is_superspeed(hdev))
 189                                 set_bit(port1, hub->warm_reset_bits);
 190                 }
 191
 192                 /* Force the child awake to revalidate after the power loss. */
 193                 if (!test_and_set_bit(port1, hub->child_usage_bits)) {
 194                         pm_runtime_get_noresume(&port_dev->dev);
 195                         pm_request_resume(&udev->dev);
 196                 }
 197         }
 198
 199         usb_autopm_put_interface(intf);
 200
 201         return retval;
 202 }
 203
 204 static int usb_port_runtime_suspend(struct device *dev)
 205 {
 206         struct usb_port *port_dev = to_usb_port(dev);
 207         struct usb_device *hdev = to_usb_device(dev->parent->parent);
 208         struct usb_interface *intf = to_usb_interface(dev->parent);
 209         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
 210         struct usb_port *peer = port_dev->peer;
 211         int port1 = port_dev->portnum;
 212         int retval;
 213
 214         if (!hub)
 215                 return -EINVAL;
 216         if (hub->in_reset)
 217                 return -EBUSY;
 218
 219         if (dev_pm_qos_flags(&port_dev->dev, PM_QOS_FLAG_NO_POWER_OFF)
 220                         == PM_QOS_FLAGS_ALL)
 221                 return -EAGAIN;
 222
 223         if (usb_port_block_power_off)
 224                 return -EBUSY;
 225
 226         usb_autopm_get_interface(intf);
 227         retval = usb_hub_set_port_power(hdev, hub, port1, false);
 228         usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
 229         if (!port_dev->is_superspeed)
 230                 usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
 231         usb_autopm_put_interface(intf);
 232
 233         /*
 234          * Our peer usb3 port may now be able to suspend, so
 235          * asynchronously queue a suspend request to observe that this
 236          * usb2 port is now off.
 237          */
 238         if (!port_dev->is_superspeed && peer)
 239                 pm_runtime_put(&peer->dev);
 240
 241         return retval;
 242 }
 243 #endif
 244
 245 static void usb_port_shutdown(struct device *dev)
 246 {
 247         struct usb_port *port_dev = to_usb_port(dev);
 248
 249         if (port_dev->child)
 250                 usb_disable_usb2_hardware_lpm(port_dev->child);
 251 }
 252
 253 static const struct dev_pm_ops usb_port_pm_ops = {
 254 #ifdef CONFIG_PM
 255         .runtime_suspend =      usb_port_runtime_suspend,
 256         .runtime_resume =       usb_port_runtime_resume,
 257 #endif
 258 };
 259
 260 struct device_type usb_port_device_type = {
 261         .name =         "usb_port",
 262         .release =      usb_port_device_release,
 263         .pm =           &usb_port_pm_ops,
 264 };
 265
 266 static struct device_driver usb_port_driver = {
 267         .name = "usb",
 268         .owner = THIS_MODULE,
 269         .shutdown = usb_port_shutdown,
 270 };
 271
 272 static int link_peers(struct usb_port *left, struct usb_port *right)
 273 {
 274         struct usb_port *ss_port, *hs_port;
 275         int rc;
 276
 277         if (left->peer == right && right->peer == left)
 278                 return 0;
 279
 280         if (left->peer || right->peer) {
 281                 struct usb_port *lpeer = left->peer;
 282                 struct usb_port *rpeer = right->peer;
 283                 char *method;
 284
 285                 if (left->location && left->location == right->location)
 286                         method = "location";
 287                 else
 288                         method = "default";
 289
 290                 pr_debug("usb: failed to peer %s and %s by %s (%s:%s) (%s:%s)\n",
 291                         dev_name(&left->dev), dev_name(&right->dev), method,
 292                         dev_name(&left->dev),
 293                         lpeer ? dev_name(&lpeer->dev) : "none",
 294                         dev_name(&right->dev),
 295                         rpeer ? dev_name(&rpeer->dev) : "none");
 296                 return -EBUSY;
 297         }
 298
 299         rc = sysfs_create_link(&left->dev.kobj, &right->dev.kobj, "peer");
 300         if (rc)
 301                 return rc;
 302         rc = sysfs_create_link(&right->dev.kobj, &left->dev.kobj, "peer");
 303         if (rc) {
 304                 sysfs_remove_link(&left->dev.kobj, "peer");
 305                 return rc;
 306         }
 307
 308         /*
 309          * We need to wake the HiSpeed port to make sure we don't race
 310          * setting ->peer with usb_port_runtime_suspend().  Otherwise we
 311          * may miss a suspend event for the SuperSpeed port.
 312          */
 313         if (left->is_superspeed) {
 314                 ss_port = left;
 315                 WARN_ON(right->is_superspeed);
 316                 hs_port = right;
 317         } else {
 318                 ss_port = right;
 319                 WARN_ON(!right->is_superspeed);
 320                 hs_port = left;
 321         }
 322         pm_runtime_get_sync(&hs_port->dev);
 323
 324         left->peer = right;
 325         right->peer = left;
 326
 327         /*
 328          * The SuperSpeed reference is dropped when the HiSpeed port in
 329          * this relationship suspends, i.e. when it is safe to allow a
 330          * SuperSpeed connection to drop since there is no risk of a
 331          * device degrading to its powered-off HiSpeed connection.
 332          *
 333          * Also, drop the HiSpeed ref taken above.
 334          */
 335         pm_runtime_get_sync(&ss_port->dev);
 336         pm_runtime_put(&hs_port->dev);
 337
 338         return 0;
 339 }
 340
 341 static void link_peers_report(struct usb_port *left, struct usb_port *right)
 342 {
 343         int rc;
 344
 345         rc = link_peers(left, right);
 346         if (rc == 0) {
 347                 dev_dbg(&left->dev, "peered to %s\n", dev_name(&right->dev));
 348         } else {
 349                 dev_dbg(&left->dev, "failed to peer to %s (%d)\n",
 350                                 dev_name(&right->dev), rc);
 351                 pr_warn_once("usb: port power management may be unreliable\n");
 352                 usb_port_block_power_off = 1;
 353         }
 354 }
 355
 356 static void unlink_peers(struct usb_port *left, struct usb_port *right)
 357 {
 358         struct usb_port *ss_port, *hs_port;
 359
 360         WARN(right->peer != left || left->peer != right,
 361                         "%s and %s are not peers?\n",
 362                         dev_name(&left->dev), dev_name(&right->dev));
 363
 364         /*
 365          * We wake the HiSpeed port to make sure we don't race its
 366          * usb_port_runtime_resume() event which takes a SuperSpeed ref
 367          * when ->peer is !NULL.
 368          */
 369         if (left->is_superspeed) {
 370                 ss_port = left;
 371                 hs_port = right;
 372         } else {
 373                 ss_port = right;
 374                 hs_port = left;
 375         }
 376
 377         pm_runtime_get_sync(&hs_port->dev);
 378
 379         sysfs_remove_link(&left->dev.kobj, "peer");
 380         right->peer = NULL;
 381         sysfs_remove_link(&right->dev.kobj, "peer");
 382         left->peer = NULL;
 383
 384         /* Drop the SuperSpeed ref held on behalf of the active HiSpeed port */
 385         pm_runtime_put(&ss_port->dev);
 386
 387         /* Drop the ref taken above */
 388         pm_runtime_put(&hs_port->dev);
 389 }
 390
 391 /*
 392  * For each usb hub device in the system check to see if it is in the
 393  * peer domain of the given port_dev, and if it is check to see if it
 394  * has a port that matches the given port by location
 395  */
 396 static int match_location(struct usb_device *peer_hdev, void *p)
 397 {
 398         int port1;
 399         struct usb_hcd *hcd, *peer_hcd;
 400         struct usb_port *port_dev = p, *peer;
 401         struct usb_hub *peer_hub = usb_hub_to_struct_hub(peer_hdev);
 402         struct usb_device *hdev = to_usb_device(port_dev->dev.parent->parent);
 403
 404         if (!peer_hub)
 405                 return 0;
 406
 407         hcd = bus_to_hcd(hdev->bus);
 408         peer_hcd = bus_to_hcd(peer_hdev->bus);
 409         /* peer_hcd is provisional until we verify it against the known peer */
 410         if (peer_hcd != hcd->shared_hcd)
 411                 return 0;
 412
 413         for (port1 = 1; port1 <= peer_hdev->maxchild; port1++) {
 414                 peer = peer_hub->ports[port1 - 1];
 415                 if (peer && peer->location == port_dev->location) {
 416                         link_peers_report(port_dev, peer);
 417                         return 1; /* done */
 418                 }
 419         }
 420
 421         return 0;
 422 }
 423
 424 /*
 425  * Find the peer port either via explicit platform firmware "location"
 426  * data, the peer hcd for root hubs, or the upstream peer relationship
 427  * for all other hubs.
 428  */
 429 static void find_and_link_peer(struct usb_hub *hub, int port1)
 430 {
 431         struct usb_port *port_dev = hub->ports[port1 - 1], *peer;
 432         struct usb_device *hdev = hub->hdev;
 433         struct usb_device *peer_hdev;
 434         struct usb_hub *peer_hub;
 435
 436         /*
 437          * If location data is available then we can only peer this port
 438          * by a location match, not the default peer (lest we create a
 439          * situation where we need to go back and undo a default peering
 440          * when the port is later peered by location data)
 441          */
 442         if (port_dev->location) {
 443                 /* we link the peer in match_location() if found */
 444                 usb_for_each_dev(port_dev, match_location);
 445                 return;
 446         } else if (!hdev->parent) {
 447                 struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
 448                 struct usb_hcd *peer_hcd = hcd->shared_hcd;
 449
 450                 if (!peer_hcd)
 451                         return;
 452
 453                 peer_hdev = peer_hcd->self.root_hub;
 454         } else {
 455                 struct usb_port *upstream;
 456                 struct usb_device *parent = hdev->parent;
 457                 struct usb_hub *parent_hub = usb_hub_to_struct_hub(parent);
 458
 459                 if (!parent_hub)
 460                         return;
 461
 462                 upstream = parent_hub->ports[hdev->portnum - 1];
 463                 if (!upstream || !upstream->peer)
 464                         return;
 465
 466                 peer_hdev = upstream->peer->child;
 467         }
 468
 469         peer_hub = usb_hub_to_struct_hub(peer_hdev);
 470         if (!peer_hub || port1 > peer_hdev->maxchild)
 471                 return;
 472
 473         /*
 474          * we found a valid default peer, last check is to make sure it
 475          * does not have location data
 476          */
 477         peer = peer_hub->ports[port1 - 1];
 478         if (peer && peer->location == 0)
 479                 link_peers_report(port_dev, peer);
 480 }
 481
 482 int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 483 {
 484         struct usb_port *port_dev;
 485         struct usb_device *hdev = hub->hdev;
 486         int retval;
 487
 488         port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
 489         if (!port_dev)
 490                 return -ENOMEM;
 491
 492         port_dev->req = kzalloc(sizeof(*(port_dev->req)), GFP_KERNEL);
 493         if (!port_dev->req) {
 494                 kfree(port_dev);
 495                 return -ENOMEM;
 496         }
 497
 498         hub->ports[port1 - 1] = port_dev;
 499         port_dev->portnum = port1;
 500         set_bit(port1, hub->power_bits);
 501         port_dev->dev.parent = hub->intfdev;
 502         if (hub_is_superspeed(hdev)) {
 503                 port_dev->usb3_lpm_u1_permit = 1;
 504                 port_dev->usb3_lpm_u2_permit = 1;
 505                 port_dev->dev.groups = port_dev_usb3_group;
 506         } else
 507                 port_dev->dev.groups = port_dev_group;
 508         port_dev->dev.type = &usb_port_device_type;
 509         port_dev->dev.driver = &usb_port_driver;
 510         if (hub_is_superspeed(hub->hdev))
 511                 port_dev->is_superspeed = 1;
 512         dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),
 513                         port1);
 514         mutex_init(&port_dev->status_lock);
 515         retval = device_register(&port_dev->dev);
 516         if (retval) {
 517                 put_device(&port_dev->dev);
 518                 return retval;
 519         }
 520
 521         /* Set default policy of port-poweroff disabled. */
 522         retval = dev_pm_qos_add_request(&port_dev->dev, port_dev->req,
 523                         DEV_PM_QOS_FLAGS, PM_QOS_FLAG_NO_POWER_OFF);
 524         if (retval < 0) {
 525                 device_unregister(&port_dev->dev);
 526                 return retval;
 527         }
 528
 529         find_and_link_peer(hub, port1);
 530
 531         /*
 532          * Enable runtime pm and hold a refernce that hub_configure()
 533          * will drop once the PM_QOS_NO_POWER_OFF flag state has been set
 534          * and the hub has been fully registered (hdev->maxchild set).
 535          */
 536         pm_runtime_set_active(&port_dev->dev);
 537         pm_runtime_get_noresume(&port_dev->dev);
 538         pm_runtime_enable(&port_dev->dev);
 539         device_enable_async_suspend(&port_dev->dev);
 540
 541         /*
 542          * Keep hidden the ability to enable port-poweroff if the hub
 543          * does not support power switching.
 544          */
 545         if (!hub_is_port_power_switchable(hub))
 546                 return 0;
 547
 548         /* Attempt to let userspace take over the policy. */
 549         retval = dev_pm_qos_expose_flags(&port_dev->dev,
 550                         PM_QOS_FLAG_NO_POWER_OFF);
 551         if (retval < 0) {
 552                 dev_warn(&port_dev->dev, "failed to expose pm_qos_no_poweroff\n");
 553                 return 0;
 554         }
 555
 556         /* Userspace owns the policy, drop the kernel 'no_poweroff' request. */
 557         retval = dev_pm_qos_remove_request(port_dev->req);
 558         if (retval >= 0) {
 559                 kfree(port_dev->req);
 560                 port_dev->req = NULL;
 561         }
 562         return 0;
 563 }
 564
 565 void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
 566 {
 567         struct usb_port *port_dev = hub->ports[port1 - 1];
 568         struct usb_port *peer;
 569
 570         peer = port_dev->peer;
 571         if (peer)
 572                 unlink_peers(port_dev, peer);
 573         device_unregister(&port_dev->dev);
 574 }