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