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 const struct attribute_group *port_dev_group[];
  25
  26 static ssize_t connect_type_show(struct device *dev,
  27                                  struct device_attribute *attr, char *buf)
  28 {
  29         struct usb_port *port_dev = to_usb_port(dev);
  30         char *result;
  31
  32         switch (port_dev->connect_type) {
  33         case USB_PORT_CONNECT_TYPE_HOT_PLUG:
  34                 result = "hotplug";
  35                 break;
  36         case USB_PORT_CONNECT_TYPE_HARD_WIRED:
  37                 result = "hardwired";
  38                 break;
  39         case USB_PORT_NOT_USED:
  40                 result = "not used";
  41                 break;
  42         default:
  43                 result = "unknown";
  44                 break;
  45         }
  46
  47         return sprintf(buf, "%s\n", result);
  48 }
  49 static DEVICE_ATTR_RO(connect_type);
  50
  51 static struct attribute *port_dev_attrs[] = {
  52         &dev_attr_connect_type.attr,
  53         NULL,
  54 };
  55
  56 static struct attribute_group port_dev_attr_grp = {
  57         .attrs = port_dev_attrs,
  58 };
  59
  60 static const struct attribute_group *port_dev_group[] = {
  61         &port_dev_attr_grp,
  62         NULL,
  63 };
  64
  65 static void usb_port_device_release(struct device *dev)
  66 {
  67         struct usb_port *port_dev = to_usb_port(dev);
  68
  69         kfree(port_dev);
  70 }
  71
  72 #ifdef CONFIG_PM_RUNTIME
  73 static int usb_port_runtime_resume(struct device *dev)
  74 {
  75         struct usb_port *port_dev = to_usb_port(dev);
  76         struct usb_device *hdev = to_usb_device(dev->parent->parent);
  77         struct usb_interface *intf = to_usb_interface(dev->parent);
  78         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
  79         struct usb_device *udev = port_dev->child;
  80         struct usb_port *peer = port_dev->peer;
  81         int port1 = port_dev->portnum;
  82         int retval;
  83
  84         if (!hub)
  85                 return -EINVAL;
  86         if (hub->in_reset) {
  87                 set_bit(port1, hub->power_bits);
  88                 return 0;
  89         }
  90
  91         /*
  92          * Power on our usb3 peer before this usb2 port to prevent a usb3
  93          * device from degrading to its usb2 connection
  94          */
  95         if (!port_dev->is_superspeed && peer)
  96                 pm_runtime_get_sync(&peer->dev);
  97
  98         usb_autopm_get_interface(intf);
  99         retval = usb_hub_set_port_power(hdev, hub, port1, true);
 100         msleep(hub_power_on_good_delay(hub));
 101         if (udev && !retval) {
 102                 /*
 103                  * Attempt to wait for usb hub port to be reconnected in order
 104                  * to make the resume procedure successful.  The device may have
 105                  * disconnected while the port was powered off, so ignore the
 106                  * return status.
 107                  */
 108                 retval = hub_port_debounce_be_connected(hub, port1);
 109                 if (retval < 0)
 110                         dev_dbg(&port_dev->dev, "can't get reconnection after setting port  power on, status %d\n",
 111                                         retval);
 112                 retval = 0;
 113
 114                 /* Force the child awake to revalidate after the power loss. */
 115                 if (!test_and_set_bit(port1, hub->child_usage_bits)) {
 116                         pm_runtime_get_noresume(&port_dev->dev);
 117                         pm_request_resume(&udev->dev);
 118                 }
 119         }
 120
 121         usb_autopm_put_interface(intf);
 122
 123         return retval;
 124 }
 125
 126 static int usb_port_runtime_suspend(struct device *dev)
 127 {
 128         struct usb_port *port_dev = to_usb_port(dev);
 129         struct usb_device *hdev = to_usb_device(dev->parent->parent);
 130         struct usb_interface *intf = to_usb_interface(dev->parent);
 131         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
 132         struct usb_port *peer = port_dev->peer;
 133         int port1 = port_dev->portnum;
 134         int retval;
 135
 136         if (!hub)
 137                 return -EINVAL;
 138         if (hub->in_reset)
 139                 return -EBUSY;
 140
 141         if (dev_pm_qos_flags(&port_dev->dev, PM_QOS_FLAG_NO_POWER_OFF)
 142                         == PM_QOS_FLAGS_ALL)
 143                 return -EAGAIN;
 144
 145         usb_autopm_get_interface(intf);
 146         retval = usb_hub_set_port_power(hdev, hub, port1, false);
 147         usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
 148         if (!port_dev->is_superspeed)
 149                 usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
 150         usb_autopm_put_interface(intf);
 151
 152         /*
 153          * Our peer usb3 port may now be able to suspend, so
 154          * asynchronously queue a suspend request to observe that this
 155          * usb2 port is now off.
 156          */
 157         if (!port_dev->is_superspeed && peer)
 158                 pm_runtime_put(&peer->dev);
 159
 160         return retval;
 161 }
 162 #endif
 163
 164 static const struct dev_pm_ops usb_port_pm_ops = {
 165 #ifdef CONFIG_PM_RUNTIME
 166         .runtime_suspend =      usb_port_runtime_suspend,
 167         .runtime_resume =       usb_port_runtime_resume,
 168 #endif
 169 };
 170
 171 struct device_type usb_port_device_type = {
 172         .name =         "usb_port",
 173         .release =      usb_port_device_release,
 174         .pm =           &usb_port_pm_ops,
 175 };
 176
 177 static struct device_driver usb_port_driver = {
 178         .name = "usb",
 179         .owner = THIS_MODULE,
 180 };
 181
 182 static int link_peers(struct usb_port *left, struct usb_port *right)
 183 {
 184         struct usb_port *ss_port, *hs_port;
 185         int rc;
 186
 187         if (left->peer == right && right->peer == left)
 188                 return 0;
 189
 190         if (left->peer || right->peer) {
 191                 struct usb_port *lpeer = left->peer;
 192                 struct usb_port *rpeer = right->peer;
 193
 194                 WARN(1, "failed to peer %s and %s (%s -> %p) (%s -> %p)\n",
 195                         dev_name(&left->dev), dev_name(&right->dev),
 196                         dev_name(&left->dev), lpeer,
 197                         dev_name(&right->dev), rpeer);
 198                 return -EBUSY;
 199         }
 200
 201         rc = sysfs_create_link(&left->dev.kobj, &right->dev.kobj, "peer");
 202         if (rc)
 203                 return rc;
 204         rc = sysfs_create_link(&right->dev.kobj, &left->dev.kobj, "peer");
 205         if (rc) {
 206                 sysfs_remove_link(&left->dev.kobj, "peer");
 207                 return rc;
 208         }
 209
 210         /*
 211          * We need to wake the HiSpeed port to make sure we don't race
 212          * setting ->peer with usb_port_runtime_suspend().  Otherwise we
 213          * may miss a suspend event for the SuperSpeed port.
 214          */
 215         if (left->is_superspeed) {
 216                 ss_port = left;
 217                 WARN_ON(right->is_superspeed);
 218                 hs_port = right;
 219         } else {
 220                 ss_port = right;
 221                 WARN_ON(!right->is_superspeed);
 222                 hs_port = left;
 223         }
 224         pm_runtime_get_sync(&hs_port->dev);
 225
 226         left->peer = right;
 227         right->peer = left;
 228
 229         /*
 230          * The SuperSpeed reference is dropped when the HiSpeed port in
 231          * this relationship suspends, i.e. when it is safe to allow a
 232          * SuperSpeed connection to drop since there is no risk of a
 233          * device degrading to its powered-off HiSpeed connection.
 234          *
 235          * Also, drop the HiSpeed ref taken above.
 236          */
 237         pm_runtime_get_sync(&ss_port->dev);
 238         pm_runtime_put(&hs_port->dev);
 239
 240         return 0;
 241 }
 242
 243 static void link_peers_report(struct usb_port *left, struct usb_port *right)
 244 {
 245         int rc;
 246
 247         rc = link_peers(left, right);
 248         if (rc == 0) {
 249                 dev_dbg(&left->dev, "peered to %s\n", dev_name(&right->dev));
 250         } else {
 251                 dev_warn(&left->dev, "failed to peer to %s (%d)\n",
 252                                 dev_name(&right->dev), rc);
 253                 pr_warn_once("usb: port power management may be unreliable\n");
 254         }
 255 }
 256
 257 static void unlink_peers(struct usb_port *left, struct usb_port *right)
 258 {
 259         struct usb_port *ss_port, *hs_port;
 260
 261         WARN(right->peer != left || left->peer != right,
 262                         "%s and %s are not peers?\n",
 263                         dev_name(&left->dev), dev_name(&right->dev));
 264
 265         /*
 266          * We wake the HiSpeed port to make sure we don't race its
 267          * usb_port_runtime_resume() event which takes a SuperSpeed ref
 268          * when ->peer is !NULL.
 269          */
 270         if (left->is_superspeed) {
 271                 ss_port = left;
 272                 hs_port = right;
 273         } else {
 274                 ss_port = right;
 275                 hs_port = left;
 276         }
 277
 278         pm_runtime_get_sync(&hs_port->dev);
 279
 280         sysfs_remove_link(&left->dev.kobj, "peer");
 281         right->peer = NULL;
 282         sysfs_remove_link(&right->dev.kobj, "peer");
 283         left->peer = NULL;
 284
 285         /* Drop the SuperSpeed ref held on behalf of the active HiSpeed port */
 286         pm_runtime_put(&ss_port->dev);
 287
 288         /* Drop the ref taken above */
 289         pm_runtime_put(&hs_port->dev);
 290 }
 291
 292 /*
 293  * For each usb hub device in the system check to see if it is in the
 294  * peer domain of the given port_dev, and if it is check to see if it
 295  * has a port that matches the given port by location
 296  */
 297 static int match_location(struct usb_device *peer_hdev, void *p)
 298 {
 299         int port1;
 300         struct usb_hcd *hcd, *peer_hcd;
 301         struct usb_port *port_dev = p, *peer;
 302         struct usb_hub *peer_hub = usb_hub_to_struct_hub(peer_hdev);
 303         struct usb_device *hdev = to_usb_device(port_dev->dev.parent->parent);
 304
 305         if (!peer_hub)
 306                 return 0;
 307
 308         hcd = bus_to_hcd(hdev->bus);
 309         peer_hcd = bus_to_hcd(peer_hdev->bus);
 310         /* peer_hcd is provisional until we verify it against the known peer */
 311         if (peer_hcd != hcd->shared_hcd)
 312                 return 0;
 313
 314         for (port1 = 1; port1 <= peer_hdev->maxchild; port1++) {
 315                 peer = peer_hub->ports[port1 - 1];
 316                 if (peer && peer->location == port_dev->location) {
 317                         link_peers_report(port_dev, peer);
 318                         return 1; /* done */
 319                 }
 320         }
 321
 322         return 0;
 323 }
 324
 325 /*
 326  * Find the peer port either via explicit platform firmware "location"
 327  * data, the peer hcd for root hubs, or the upstream peer relationship
 328  * for all other hubs.
 329  */
 330 static void find_and_link_peer(struct usb_hub *hub, int port1)
 331 {
 332         struct usb_port *port_dev = hub->ports[port1 - 1], *peer;
 333         struct usb_device *hdev = hub->hdev;
 334         struct usb_device *peer_hdev;
 335         struct usb_hub *peer_hub;
 336
 337         /*
 338          * If location data is available then we can only peer this port
 339          * by a location match, not the default peer (lest we create a
 340          * situation where we need to go back and undo a default peering
 341          * when the port is later peered by location data)
 342          */
 343         if (port_dev->location) {
 344                 /* we link the peer in match_location() if found */
 345                 usb_for_each_dev(port_dev, match_location);
 346                 return;
 347         } else if (!hdev->parent) {
 348                 struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
 349                 struct usb_hcd *peer_hcd = hcd->shared_hcd;
 350
 351                 if (!peer_hcd)
 352                         return;
 353
 354                 peer_hdev = peer_hcd->self.root_hub;
 355         } else {
 356                 struct usb_port *upstream;
 357                 struct usb_device *parent = hdev->parent;
 358                 struct usb_hub *parent_hub = usb_hub_to_struct_hub(parent);
 359
 360                 if (!parent_hub)
 361                         return;
 362
 363                 upstream = parent_hub->ports[hdev->portnum - 1];
 364                 if (!upstream || !upstream->peer)
 365                         return;
 366
 367                 peer_hdev = upstream->peer->child;
 368         }
 369
 370         peer_hub = usb_hub_to_struct_hub(peer_hdev);
 371         if (!peer_hub || port1 > peer_hdev->maxchild)
 372                 return;
 373
 374         /*
 375          * we found a valid default peer, last check is to make sure it
 376          * does not have location data
 377          */
 378         peer = peer_hub->ports[port1 - 1];
 379         if (peer && peer->location == 0)
 380                 link_peers_report(port_dev, peer);
 381 }
 382
 383 int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 384 {
 385         struct usb_port *port_dev;
 386         int retval;
 387
 388         port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
 389         if (!port_dev) {
 390                 retval = -ENOMEM;
 391                 goto exit;
 392         }
 393
 394         hub->ports[port1 - 1] = port_dev;
 395         port_dev->portnum = port1;
 396         set_bit(port1, hub->power_bits);
 397         port_dev->dev.parent = hub->intfdev;
 398         port_dev->dev.groups = port_dev_group;
 399         port_dev->dev.type = &usb_port_device_type;
 400         port_dev->dev.driver = &usb_port_driver;
 401         if (hub_is_superspeed(hub->hdev))
 402                 port_dev->is_superspeed = 1;
 403         dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),
 404                         port1);
 405         mutex_init(&port_dev->status_lock);
 406         retval = device_register(&port_dev->dev);
 407         if (retval)
 408                 goto error_register;
 409
 410         find_and_link_peer(hub, port1);
 411
 412         pm_runtime_set_active(&port_dev->dev);
 413
 414         /*
 415          * Do not enable port runtime pm if the hub does not support
 416          * power switching.  Also, userspace must have final say of
 417          * whether a port is permitted to power-off.  Do not enable
 418          * runtime pm if we fail to expose pm_qos_no_power_off.
 419          */
 420         if (hub_is_port_power_switchable(hub)
 421                         && dev_pm_qos_expose_flags(&port_dev->dev,
 422                         PM_QOS_FLAG_NO_POWER_OFF) == 0)
 423                 pm_runtime_enable(&port_dev->dev);
 424
 425         device_enable_async_suspend(&port_dev->dev);
 426         return 0;
 427
 428 error_register:
 429         put_device(&port_dev->dev);
 430 exit:
 431         return retval;
 432 }
 433
 434 void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
 435 {
 436         struct usb_port *port_dev = hub->ports[port1 - 1];
 437         struct usb_port *peer;
 438
 439         peer = port_dev->peer;
 440         if (peer)
 441                 unlink_peers(port_dev, peer);
 442         device_unregister(&port_dev->dev);
 443 }