drivers/usb/core/port.c

   1 /*
   2  * usb port device code
   3  *
   4  * Copyright (C) 2012 Intel Corp
   5  *
   6  * Author: Lan Tianyu <tianyu.lan@intel.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15  * for more details.
  16  *
  17  */
  18
  19 #include <linux/slab.h>
  20 #include <linux/pm_qos.h>
  21
  22 #include "hub.h"
  23
  24 static int usb_port_block_power_off;
  25
  26 static const struct attribute_group *port_dev_group[];
  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 struct attribute *port_dev_attrs[] = {
  54         &dev_attr_connect_type.attr,
  55         NULL,
  56 };
  57
  58 static struct attribute_group port_dev_attr_grp = {
  59         .attrs = port_dev_attrs,
  60 };
  61
  62 static const struct attribute_group *port_dev_group[] = {
  63         &port_dev_attr_grp,
  64         NULL,
  65 };
  66
  67 static void usb_port_device_release(struct device *dev)
  68 {
  69         struct usb_port *port_dev = to_usb_port(dev);
  70
  71         kfree(port_dev->req);
  72         kfree(port_dev);
  73 }
  74
  75 #ifdef CONFIG_PM
  76 static int usb_port_runtime_resume(struct device *dev)
  77 {
  78         struct usb_port *port_dev = to_usb_port(dev);
  79         struct usb_device *hdev = to_usb_device(dev->parent->parent);
  80         struct usb_interface *intf = to_usb_interface(dev->parent);
  81         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
  82         struct usb_device *udev = port_dev->child;
  83         struct usb_port *peer = port_dev->peer;
  84         int port1 = port_dev->portnum;
  85         int retval;
  86
  87         if (!hub)
  88                 return -EINVAL;
  89         if (hub->in_reset) {
  90                 set_bit(port1, hub->power_bits);
  91                 return 0;
  92         }
  93
  94         /*
  95          * Power on our usb3 peer before this usb2 port to prevent a usb3
  96          * device from degrading to its usb2 connection
  97          */
  98         if (!port_dev->is_superspeed && peer)
  99                 pm_runtime_get_sync(&peer->dev);
 100
 101         usb_autopm_get_interface(intf);
 102         retval = usb_hub_set_port_power(hdev, hub, port1, true);
 103         msleep(hub_power_on_good_delay(hub));
 104         if (udev && !retval) {
 105                 /*
 106                  * Our preference is to simply wait for the port to reconnect,
 107                  * as that is the lowest latency method to restart the port.
 108                  * However, there are cases where toggling port power results in
 109                  * the host port and the device port getting out of sync causing
 110                  * a link training live lock.  Upon timeout, flag the port as
 111                  * needing warm reset recovery (to be performed later by
 112                  * usb_port_resume() as requested via usb_wakeup_notification())
 113                  */
 114                 if (hub_port_debounce_be_connected(hub, port1) < 0) {
 115                         dev_dbg(&port_dev->dev, "reconnect timeout\n");
 116                         if (hub_is_superspeed(hdev))
 117                                 set_bit(port1, hub->warm_reset_bits);
 118                 }
 119
 120                 /* Force the child awake to revalidate after the power loss. */
 121                 if (!test_and_set_bit(port1, hub->child_usage_bits)) {
 122                         pm_runtime_get_noresume(&port_dev->dev);
 123                         pm_request_resume(&udev->dev);
 124                 }
 125         }
 126
 127         usb_autopm_put_interface(intf);
 128
 129         return retval;
 130 }
 131
 132 static int usb_port_runtime_suspend(struct device *dev)
 133 {
 134         struct usb_port *port_dev = to_usb_port(dev);
 135         struct usb_device *hdev = to_usb_device(dev->parent->parent);
 136         struct usb_interface *intf = to_usb_interface(dev->parent);
 137         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
 138         struct usb_port *peer = port_dev->peer;
 139         int port1 = port_dev->portnum;
 140         int retval;
 141
 142         if (!hub)
 143                 return -EINVAL;
 144         if (hub->in_reset)
 145                 return -EBUSY;
 146
 147         if (dev_pm_qos_flags(&port_dev->dev, PM_QOS_FLAG_NO_POWER_OFF)
 148                         == PM_QOS_FLAGS_ALL)
 149                 return -EAGAIN;
 150
 151         if (usb_port_block_power_off)
 152                 return -EBUSY;
 153
 154         usb_autopm_get_interface(intf);
 155         retval = usb_hub_set_port_power(hdev, hub, port1, false);
 156         usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
 157         if (!port_dev->is_superspeed)
 158                 usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
 159         usb_autopm_put_interface(intf);
 160
 161         /*
 162          * Our peer usb3 port may now be able to suspend, so
 163          * asynchronously queue a suspend request to observe that this
 164          * usb2 port is now off.
 165          */
 166         if (!port_dev->is_superspeed && peer)
 167                 pm_runtime_put(&peer->dev);
 168
 169         return retval;
 170 }
 171 #endif
 172
 173 static const struct dev_pm_ops usb_port_pm_ops = {
 174 #ifdef CONFIG_PM
 175         .runtime_suspend =      usb_port_runtime_suspend,
 176         .runtime_resume =       usb_port_runtime_resume,
 177 #endif
 178 };
 179
 180 struct device_type usb_port_device_type = {
 181         .name =         "usb_port",
 182         .release =      usb_port_device_release,
 183         .pm =           &usb_port_pm_ops,
 184 };
 185
 186 static struct device_driver usb_port_driver = {
 187         .name = "usb",
 188         .owner = THIS_MODULE,
 189 };
 190
 191 static int link_peers(struct usb_port *left, struct usb_port *right)
 192 {
 193         struct usb_port *ss_port, *hs_port;
 194         int rc;
 195
 196         if (left->peer == right && right->peer == left)
 197                 return 0;
 198
 199         if (left->peer || right->peer) {
 200                 struct usb_port *lpeer = left->peer;
 201                 struct usb_port *rpeer = right->peer;
 202                 char *method;
 203
 204                 if (left->location && left->location == right->location)
 205                         method = "location";
 206                 else
 207                         method = "default";
 208
 209                 pr_debug("usb: failed to peer %s and %s by %s (%s:%s) (%s:%s)\n",
 210                         dev_name(&left->dev), dev_name(&right->dev), method,
 211                         dev_name(&left->dev),
 212                         lpeer ? dev_name(&lpeer->dev) : "none",
 213                         dev_name(&right->dev),
 214                         rpeer ? dev_name(&rpeer->dev) : "none");
 215                 return -EBUSY;
 216         }
 217
 218         rc = sysfs_create_link(&left->dev.kobj, &right->dev.kobj, "peer");
 219         if (rc)
 220                 return rc;
 221         rc = sysfs_create_link(&right->dev.kobj, &left->dev.kobj, "peer");
 222         if (rc) {
 223                 sysfs_remove_link(&left->dev.kobj, "peer");
 224                 return rc;
 225         }
 226
 227         /*
 228          * We need to wake the HiSpeed port to make sure we don't race
 229          * setting ->peer with usb_port_runtime_suspend().  Otherwise we
 230          * may miss a suspend event for the SuperSpeed port.
 231          */
 232         if (left->is_superspeed) {
 233                 ss_port = left;
 234                 WARN_ON(right->is_superspeed);
 235                 hs_port = right;
 236         } else {
 237                 ss_port = right;
 238                 WARN_ON(!right->is_superspeed);
 239                 hs_port = left;
 240         }
 241         pm_runtime_get_sync(&hs_port->dev);
 242
 243         left->peer = right;
 244         right->peer = left;
 245
 246         /*
 247          * The SuperSpeed reference is dropped when the HiSpeed port in
 248          * this relationship suspends, i.e. when it is safe to allow a
 249          * SuperSpeed connection to drop since there is no risk of a
 250          * device degrading to its powered-off HiSpeed connection.
 251          *
 252          * Also, drop the HiSpeed ref taken above.
 253          */
 254         pm_runtime_get_sync(&ss_port->dev);
 255         pm_runtime_put(&hs_port->dev);
 256
 257         return 0;
 258 }
 259
 260 static void link_peers_report(struct usb_port *left, struct usb_port *right)
 261 {
 262         int rc;
 263
 264         rc = link_peers(left, right);
 265         if (rc == 0) {
 266                 dev_dbg(&left->dev, "peered to %s\n", dev_name(&right->dev));
 267         } else {
 268                 dev_dbg(&left->dev, "failed to peer to %s (%d)\n",
 269                                 dev_name(&right->dev), rc);
 270                 pr_warn_once("usb: port power management may be unreliable\n");
 271                 usb_port_block_power_off = 1;
 272         }
 273 }
 274
 275 static void unlink_peers(struct usb_port *left, struct usb_port *right)
 276 {
 277         struct usb_port *ss_port, *hs_port;
 278
 279         WARN(right->peer != left || left->peer != right,
 280                         "%s and %s are not peers?\n",
 281                         dev_name(&left->dev), dev_name(&right->dev));
 282
 283         /*
 284          * We wake the HiSpeed port to make sure we don't race its
 285          * usb_port_runtime_resume() event which takes a SuperSpeed ref
 286          * when ->peer is !NULL.
 287          */
 288         if (left->is_superspeed) {
 289                 ss_port = left;
 290                 hs_port = right;
 291         } else {
 292                 ss_port = right;
 293                 hs_port = left;
 294         }
 295
 296         pm_runtime_get_sync(&hs_port->dev);
 297
 298         sysfs_remove_link(&left->dev.kobj, "peer");
 299         right->peer = NULL;
 300         sysfs_remove_link(&right->dev.kobj, "peer");
 301         left->peer = NULL;
 302
 303         /* Drop the SuperSpeed ref held on behalf of the active HiSpeed port */
 304         pm_runtime_put(&ss_port->dev);
 305
 306         /* Drop the ref taken above */
 307         pm_runtime_put(&hs_port->dev);
 308 }
 309
 310 /*
 311  * For each usb hub device in the system check to see if it is in the
 312  * peer domain of the given port_dev, and if it is check to see if it
 313  * has a port that matches the given port by location
 314  */
 315 static int match_location(struct usb_device *peer_hdev, void *p)
 316 {
 317         int port1;
 318         struct usb_hcd *hcd, *peer_hcd;
 319         struct usb_port *port_dev = p, *peer;
 320         struct usb_hub *peer_hub = usb_hub_to_struct_hub(peer_hdev);
 321         struct usb_device *hdev = to_usb_device(port_dev->dev.parent->parent);
 322
 323         if (!peer_hub)
 324                 return 0;
 325
 326         hcd = bus_to_hcd(hdev->bus);
 327         peer_hcd = bus_to_hcd(peer_hdev->bus);
 328         /* peer_hcd is provisional until we verify it against the known peer */
 329         if (peer_hcd != hcd->shared_hcd)
 330                 return 0;
 331
 332         for (port1 = 1; port1 <= peer_hdev->maxchild; port1++) {
 333                 peer = peer_hub->ports[port1 - 1];
 334                 if (peer && peer->location == port_dev->location) {
 335                         link_peers_report(port_dev, peer);
 336                         return 1; /* done */
 337                 }
 338         }
 339
 340         return 0;
 341 }
 342
 343 /*
 344  * Find the peer port either via explicit platform firmware "location"
 345  * data, the peer hcd for root hubs, or the upstream peer relationship
 346  * for all other hubs.
 347  */
 348 static void find_and_link_peer(struct usb_hub *hub, int port1)
 349 {
 350         struct usb_port *port_dev = hub->ports[port1 - 1], *peer;
 351         struct usb_device *hdev = hub->hdev;
 352         struct usb_device *peer_hdev;
 353         struct usb_hub *peer_hub;
 354
 355         /*
 356          * If location data is available then we can only peer this port
 357          * by a location match, not the default peer (lest we create a
 358          * situation where we need to go back and undo a default peering
 359          * when the port is later peered by location data)
 360          */
 361         if (port_dev->location) {
 362                 /* we link the peer in match_location() if found */
 363                 usb_for_each_dev(port_dev, match_location);
 364                 return;
 365         } else if (!hdev->parent) {
 366                 struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
 367                 struct usb_hcd *peer_hcd = hcd->shared_hcd;
 368
 369                 if (!peer_hcd)
 370                         return;
 371
 372                 peer_hdev = peer_hcd->self.root_hub;
 373         } else {
 374                 struct usb_port *upstream;
 375                 struct usb_device *parent = hdev->parent;
 376                 struct usb_hub *parent_hub = usb_hub_to_struct_hub(parent);
 377
 378                 if (!parent_hub)
 379                         return;
 380
 381                 upstream = parent_hub->ports[hdev->portnum - 1];
 382                 if (!upstream || !upstream->peer)
 383                         return;
 384
 385                 peer_hdev = upstream->peer->child;
 386         }
 387
 388         peer_hub = usb_hub_to_struct_hub(peer_hdev);
 389         if (!peer_hub || port1 > peer_hdev->maxchild)
 390                 return;
 391
 392         /*
 393          * we found a valid default peer, last check is to make sure it
 394          * does not have location data
 395          */
 396         peer = peer_hub->ports[port1 - 1];
 397         if (peer && peer->location == 0)
 398                 link_peers_report(port_dev, peer);
 399 }
 400
 401 int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 402 {
 403         struct usb_port *port_dev;
 404         int retval;
 405
 406         port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
 407         if (!port_dev)
 408                 return -ENOMEM;
 409
 410         port_dev->req = kzalloc(sizeof(*(port_dev->req)), GFP_KERNEL);
 411         if (!port_dev->req) {
 412                 kfree(port_dev);
 413                 return -ENOMEM;
 414         }
 415
 416         hub->ports[port1 - 1] = port_dev;
 417         port_dev->portnum = port1;
 418         set_bit(port1, hub->power_bits);
 419         port_dev->dev.parent = hub->intfdev;
 420         port_dev->dev.groups = port_dev_group;
 421         port_dev->dev.type = &usb_port_device_type;
 422         port_dev->dev.driver = &usb_port_driver;
 423         if (hub_is_superspeed(hub->hdev))
 424                 port_dev->is_superspeed = 1;
 425         dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),
 426                         port1);
 427         mutex_init(&port_dev->status_lock);
 428         retval = device_register(&port_dev->dev);
 429         if (retval) {
 430                 put_device(&port_dev->dev);
 431                 return retval;
 432         }
 433
 434         /* Set default policy of port-poweroff disabled. */
 435         retval = dev_pm_qos_add_request(&port_dev->dev, port_dev->req,
 436                         DEV_PM_QOS_FLAGS, PM_QOS_FLAG_NO_POWER_OFF);
 437         if (retval < 0) {
 438                 device_unregister(&port_dev->dev);
 439                 return retval;
 440         }
 441
 442         find_and_link_peer(hub, port1);
 443
 444         /*
 445          * Enable runtime pm and hold a refernce that hub_configure()
 446          * will drop once the PM_QOS_NO_POWER_OFF flag state has been set
 447          * and the hub has been fully registered (hdev->maxchild set).
 448          */
 449         pm_runtime_set_active(&port_dev->dev);
 450         pm_runtime_get_noresume(&port_dev->dev);
 451         pm_runtime_enable(&port_dev->dev);
 452         device_enable_async_suspend(&port_dev->dev);
 453
 454         /*
 455          * Keep hidden the ability to enable port-poweroff if the hub
 456          * does not support power switching.
 457          */
 458         if (!hub_is_port_power_switchable(hub))
 459                 return 0;
 460
 461         /* Attempt to let userspace take over the policy. */
 462         retval = dev_pm_qos_expose_flags(&port_dev->dev,
 463                         PM_QOS_FLAG_NO_POWER_OFF);
 464         if (retval < 0) {
 465                 dev_warn(&port_dev->dev, "failed to expose pm_qos_no_poweroff\n");
 466                 return 0;
 467         }
 468
 469         /* Userspace owns the policy, drop the kernel 'no_poweroff' request. */
 470         retval = dev_pm_qos_remove_request(port_dev->req);
 471         if (retval >= 0) {
 472                 kfree(port_dev->req);
 473                 port_dev->req = NULL;
 474         }
 475         return 0;
 476 }
 477
 478 void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
 479 {
 480         struct usb_port *port_dev = hub->ports[port1 - 1];
 481         struct usb_port *peer;
 482
 483         peer = port_dev->peer;
 484         if (peer)
 485                 unlink_peers(port_dev, peer);
 486         device_unregister(&port_dev->dev);
 487 }