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);
  72 }
  73
  74 #ifdef CONFIG_PM_RUNTIME
  75 static int usb_port_runtime_resume(struct device *dev)
  76 {
  77         struct usb_port *port_dev = to_usb_port(dev);
  78         struct usb_device *hdev = to_usb_device(dev->parent->parent);
  79         struct usb_interface *intf = to_usb_interface(dev->parent);
  80         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
  81         struct usb_device *udev = port_dev->child;
  82         struct usb_port *peer = port_dev->peer;
  83         int port1 = port_dev->portnum;
  84         int retval;
  85
  86         if (!hub)
  87                 return -EINVAL;
  88         if (hub->in_reset) {
  89                 set_bit(port1, hub->power_bits);
  90                 return 0;
  91         }
  92
  93         /*
  94          * Power on our usb3 peer before this usb2 port to prevent a usb3
  95          * device from degrading to its usb2 connection
  96          */
  97         if (!port_dev->is_superspeed && peer)
  98                 pm_runtime_get_sync(&peer->dev);
  99
 100         usb_autopm_get_interface(intf);
 101         retval = usb_hub_set_port_power(hdev, hub, port1, true);
 102         msleep(hub_power_on_good_delay(hub));
 103         if (udev && !retval) {
 104                 /*
 105                  * Attempt to wait for usb hub port to be reconnected in order
 106                  * to make the resume procedure successful.  The device may have
 107                  * disconnected while the port was powered off, so ignore the
 108                  * return status.
 109                  */
 110                 retval = hub_port_debounce_be_connected(hub, port1);
 111                 if (retval < 0)
 112                         dev_dbg(&port_dev->dev, "can't get reconnection after setting port  power on, status %d\n",
 113                                         retval);
 114                 retval = 0;
 115
 116                 /* Force the child awake to revalidate after the power loss. */
 117                 if (!test_and_set_bit(port1, hub->child_usage_bits)) {
 118                         pm_runtime_get_noresume(&port_dev->dev);
 119                         pm_request_resume(&udev->dev);
 120                 }
 121         }
 122
 123         usb_autopm_put_interface(intf);
 124
 125         return retval;
 126 }
 127
 128 static int usb_port_runtime_suspend(struct device *dev)
 129 {
 130         struct usb_port *port_dev = to_usb_port(dev);
 131         struct usb_device *hdev = to_usb_device(dev->parent->parent);
 132         struct usb_interface *intf = to_usb_interface(dev->parent);
 133         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
 134         struct usb_port *peer = port_dev->peer;
 135         int port1 = port_dev->portnum;
 136         int retval;
 137
 138         if (!hub)
 139                 return -EINVAL;
 140         if (hub->in_reset)
 141                 return -EBUSY;
 142
 143         if (dev_pm_qos_flags(&port_dev->dev, PM_QOS_FLAG_NO_POWER_OFF)
 144                         == PM_QOS_FLAGS_ALL)
 145                 return -EAGAIN;
 146
 147         if (usb_port_block_power_off)
 148                 return -EBUSY;
 149
 150         usb_autopm_get_interface(intf);
 151         retval = usb_hub_set_port_power(hdev, hub, port1, false);
 152         usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
 153         if (!port_dev->is_superspeed)
 154                 usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
 155         usb_autopm_put_interface(intf);
 156
 157         /*
 158          * Our peer usb3 port may now be able to suspend, so
 159          * asynchronously queue a suspend request to observe that this
 160          * usb2 port is now off.
 161          */
 162         if (!port_dev->is_superspeed && peer)
 163                 pm_runtime_put(&peer->dev);
 164
 165         return retval;
 166 }
 167 #endif
 168
 169 static const struct dev_pm_ops usb_port_pm_ops = {
 170 #ifdef CONFIG_PM_RUNTIME
 171         .runtime_suspend =      usb_port_runtime_suspend,
 172         .runtime_resume =       usb_port_runtime_resume,
 173 #endif
 174 };
 175
 176 struct device_type usb_port_device_type = {
 177         .name =         "usb_port",
 178         .release =      usb_port_device_release,
 179         .pm =           &usb_port_pm_ops,
 180 };
 181
 182 static struct device_driver usb_port_driver = {
 183         .name = "usb",
 184         .owner = THIS_MODULE,
 185 };
 186
 187 static int link_peers(struct usb_port *left, struct usb_port *right)
 188 {
 189         struct usb_port *ss_port, *hs_port;
 190         int rc;
 191
 192         if (left->peer == right && right->peer == left)
 193                 return 0;
 194
 195         if (left->peer || right->peer) {
 196                 struct usb_port *lpeer = left->peer;
 197                 struct usb_port *rpeer = right->peer;
 198                 char *method;
 199
 200                 if (left->location && left->location == right->location)
 201                         method = "location";
 202                 else
 203                         method = "default";
 204
 205                 pr_warn("usb: failed to peer %s and %s by %s (%s:%s) (%s:%s)\n",
 206                         dev_name(&left->dev), dev_name(&right->dev), method,
 207                         dev_name(&left->dev),
 208                         lpeer ? dev_name(&lpeer->dev) : "none",
 209                         dev_name(&right->dev),
 210                         rpeer ? dev_name(&rpeer->dev) : "none");
 211                 return -EBUSY;
 212         }
 213
 214         rc = sysfs_create_link(&left->dev.kobj, &right->dev.kobj, "peer");
 215         if (rc)
 216                 return rc;
 217         rc = sysfs_create_link(&right->dev.kobj, &left->dev.kobj, "peer");
 218         if (rc) {
 219                 sysfs_remove_link(&left->dev.kobj, "peer");
 220                 return rc;
 221         }
 222
 223         /*
 224          * We need to wake the HiSpeed port to make sure we don't race
 225          * setting ->peer with usb_port_runtime_suspend().  Otherwise we
 226          * may miss a suspend event for the SuperSpeed port.
 227          */
 228         if (left->is_superspeed) {
 229                 ss_port = left;
 230                 WARN_ON(right->is_superspeed);
 231                 hs_port = right;
 232         } else {
 233                 ss_port = right;
 234                 WARN_ON(!right->is_superspeed);
 235                 hs_port = left;
 236         }
 237         pm_runtime_get_sync(&hs_port->dev);
 238
 239         left->peer = right;
 240         right->peer = left;
 241
 242         /*
 243          * The SuperSpeed reference is dropped when the HiSpeed port in
 244          * this relationship suspends, i.e. when it is safe to allow a
 245          * SuperSpeed connection to drop since there is no risk of a
 246          * device degrading to its powered-off HiSpeed connection.
 247          *
 248          * Also, drop the HiSpeed ref taken above.
 249          */
 250         pm_runtime_get_sync(&ss_port->dev);
 251         pm_runtime_put(&hs_port->dev);
 252
 253         return 0;
 254 }
 255
 256 static void link_peers_report(struct usb_port *left, struct usb_port *right)
 257 {
 258         int rc;
 259
 260         rc = link_peers(left, right);
 261         if (rc == 0) {
 262                 dev_dbg(&left->dev, "peered to %s\n", dev_name(&right->dev));
 263         } else {
 264                 dev_warn(&left->dev, "failed to peer to %s (%d)\n",
 265                                 dev_name(&right->dev), rc);
 266                 pr_warn_once("usb: port power management may be unreliable\n");
 267                 usb_port_block_power_off = 1;
 268         }
 269 }
 270
 271 static void unlink_peers(struct usb_port *left, struct usb_port *right)
 272 {
 273         struct usb_port *ss_port, *hs_port;
 274
 275         WARN(right->peer != left || left->peer != right,
 276                         "%s and %s are not peers?\n",
 277                         dev_name(&left->dev), dev_name(&right->dev));
 278
 279         /*
 280          * We wake the HiSpeed port to make sure we don't race its
 281          * usb_port_runtime_resume() event which takes a SuperSpeed ref
 282          * when ->peer is !NULL.
 283          */
 284         if (left->is_superspeed) {
 285                 ss_port = left;
 286                 hs_port = right;
 287         } else {
 288                 ss_port = right;
 289                 hs_port = left;
 290         }
 291
 292         pm_runtime_get_sync(&hs_port->dev);
 293
 294         sysfs_remove_link(&left->dev.kobj, "peer");
 295         right->peer = NULL;
 296         sysfs_remove_link(&right->dev.kobj, "peer");
 297         left->peer = NULL;
 298
 299         /* Drop the SuperSpeed ref held on behalf of the active HiSpeed port */
 300         pm_runtime_put(&ss_port->dev);
 301
 302         /* Drop the ref taken above */
 303         pm_runtime_put(&hs_port->dev);
 304 }
 305
 306 /*
 307  * For each usb hub device in the system check to see if it is in the
 308  * peer domain of the given port_dev, and if it is check to see if it
 309  * has a port that matches the given port by location
 310  */
 311 static int match_location(struct usb_device *peer_hdev, void *p)
 312 {
 313         int port1;
 314         struct usb_hcd *hcd, *peer_hcd;
 315         struct usb_port *port_dev = p, *peer;
 316         struct usb_hub *peer_hub = usb_hub_to_struct_hub(peer_hdev);
 317         struct usb_device *hdev = to_usb_device(port_dev->dev.parent->parent);
 318
 319         if (!peer_hub)
 320                 return 0;
 321
 322         hcd = bus_to_hcd(hdev->bus);
 323         peer_hcd = bus_to_hcd(peer_hdev->bus);
 324         /* peer_hcd is provisional until we verify it against the known peer */
 325         if (peer_hcd != hcd->shared_hcd)
 326                 return 0;
 327
 328         for (port1 = 1; port1 <= peer_hdev->maxchild; port1++) {
 329                 peer = peer_hub->ports[port1 - 1];
 330                 if (peer && peer->location == port_dev->location) {
 331                         link_peers_report(port_dev, peer);
 332                         return 1; /* done */
 333                 }
 334         }
 335
 336         return 0;
 337 }
 338
 339 /*
 340  * Find the peer port either via explicit platform firmware "location"
 341  * data, the peer hcd for root hubs, or the upstream peer relationship
 342  * for all other hubs.
 343  */
 344 static void find_and_link_peer(struct usb_hub *hub, int port1)
 345 {
 346         struct usb_port *port_dev = hub->ports[port1 - 1], *peer;
 347         struct usb_device *hdev = hub->hdev;
 348         struct usb_device *peer_hdev;
 349         struct usb_hub *peer_hub;
 350
 351         /*
 352          * If location data is available then we can only peer this port
 353          * by a location match, not the default peer (lest we create a
 354          * situation where we need to go back and undo a default peering
 355          * when the port is later peered by location data)
 356          */
 357         if (port_dev->location) {
 358                 /* we link the peer in match_location() if found */
 359                 usb_for_each_dev(port_dev, match_location);
 360                 return;
 361         } else if (!hdev->parent) {
 362                 struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
 363                 struct usb_hcd *peer_hcd = hcd->shared_hcd;
 364
 365                 if (!peer_hcd)
 366                         return;
 367
 368                 peer_hdev = peer_hcd->self.root_hub;
 369         } else {
 370                 struct usb_port *upstream;
 371                 struct usb_device *parent = hdev->parent;
 372                 struct usb_hub *parent_hub = usb_hub_to_struct_hub(parent);
 373
 374                 if (!parent_hub)
 375                         return;
 376
 377                 upstream = parent_hub->ports[hdev->portnum - 1];
 378                 if (!upstream || !upstream->peer)
 379                         return;
 380
 381                 peer_hdev = upstream->peer->child;
 382         }
 383
 384         peer_hub = usb_hub_to_struct_hub(peer_hdev);
 385         if (!peer_hub || port1 > peer_hdev->maxchild)
 386                 return;
 387
 388         /*
 389          * we found a valid default peer, last check is to make sure it
 390          * does not have location data
 391          */
 392         peer = peer_hub->ports[port1 - 1];
 393         if (peer && peer->location == 0)
 394                 link_peers_report(port_dev, peer);
 395 }
 396
 397 int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 398 {
 399         struct usb_port *port_dev;
 400         int retval;
 401
 402         port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
 403         if (!port_dev) {
 404                 retval = -ENOMEM;
 405                 goto exit;
 406         }
 407
 408         hub->ports[port1 - 1] = port_dev;
 409         port_dev->portnum = port1;
 410         set_bit(port1, hub->power_bits);
 411         port_dev->dev.parent = hub->intfdev;
 412         port_dev->dev.groups = port_dev_group;
 413         port_dev->dev.type = &usb_port_device_type;
 414         port_dev->dev.driver = &usb_port_driver;
 415         if (hub_is_superspeed(hub->hdev))
 416                 port_dev->is_superspeed = 1;
 417         dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),
 418                         port1);
 419         mutex_init(&port_dev->status_lock);
 420         retval = device_register(&port_dev->dev);
 421         if (retval)
 422                 goto error_register;
 423
 424         find_and_link_peer(hub, port1);
 425
 426         pm_runtime_set_active(&port_dev->dev);
 427
 428         /*
 429          * Do not enable port runtime pm if the hub does not support
 430          * power switching.  Also, userspace must have final say of
 431          * whether a port is permitted to power-off.  Do not enable
 432          * runtime pm if we fail to expose pm_qos_no_power_off.
 433          */
 434         if (hub_is_port_power_switchable(hub)
 435                         && dev_pm_qos_expose_flags(&port_dev->dev,
 436                         PM_QOS_FLAG_NO_POWER_OFF) == 0)
 437                 pm_runtime_enable(&port_dev->dev);
 438
 439         device_enable_async_suspend(&port_dev->dev);
 440         return 0;
 441
 442 error_register:
 443         put_device(&port_dev->dev);
 444 exit:
 445         return retval;
 446 }
 447
 448 void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
 449 {
 450         struct usb_port *port_dev = hub->ports[port1 - 1];
 451         struct usb_port *peer;
 452
 453         peer = port_dev->peer;
 454         if (peer)
 455                 unlink_peers(port_dev, peer);
 456         device_unregister(&port_dev->dev);
 457 }