root/drivers/usb/core/usb.c

DEFINITIONS

1. usb_disabled
2. match_endpoint
3. usb_find_common_endpoints
4. usb_find_common_endpoints_reverse
5. usb_find_alt_setting
6. usb_ifnum_to_if
7. usb_altnum_to_altsetting
8. __find_interface
9. usb_find_interface
10. __each_dev
11. usb_for_each_dev
12. usb_release_dev
13. usb_dev_uevent
14. usb_dev_prepare
15. usb_dev_complete
16. usb_dev_suspend
17. usb_dev_resume
18. usb_dev_freeze
19. usb_dev_thaw
20. usb_dev_poweroff
21. usb_dev_restore
22. usb_devnode
23. usb_bus_is_wusb
24. usb_dev_authorized
25. usb_alloc_dev
26. usb_get_dev
27. usb_put_dev
28. usb_get_intf
29. usb_put_intf
30. usb_lock_device_for_reset
31. usb_get_current_frame_number
32. __usb_get_extra_descriptor
33. usb_alloc_coherent
34. usb_free_coherent
35. usb_bus_notify
36. usb_debugfs_init
37. usb_debugfs_cleanup
38. usb_init
39. usb_exit

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * drivers/usb/core/usb.c
   4  *
   5  * (C) Copyright Linus Torvalds 1999
   6  * (C) Copyright Johannes Erdfelt 1999-2001
   7  * (C) Copyright Andreas Gal 1999
   8  * (C) Copyright Gregory P. Smith 1999
   9  * (C) Copyright Deti Fliegl 1999 (new USB architecture)
  10  * (C) Copyright Randy Dunlap 2000
  11  * (C) Copyright David Brownell 2000-2004
  12  * (C) Copyright Yggdrasil Computing, Inc. 2000
  13  *     (usb_device_id matching changes by Adam J. Richter)
  14  * (C) Copyright Greg Kroah-Hartman 2002-2003
  15  *
  16  * Released under the GPLv2 only.
  17  *
  18  * NOTE! This is not actually a driver at all, rather this is
  19  * just a collection of helper routines that implement the
  20  * generic USB things that the real drivers can use..
  21  *
  22  * Think of this as a "USB library" rather than anything else.
  23  * It should be considered a slave, with no callbacks. Callbacks
  24  * are evil.
  25  */
  26 
  27 #include <linux/module.h>
  28 #include <linux/moduleparam.h>
  29 #include <linux/string.h>
  30 #include <linux/bitops.h>
  31 #include <linux/slab.h>
  32 #include <linux/interrupt.h>  /* for in_interrupt() */
  33 #include <linux/kmod.h>
  34 #include <linux/init.h>
  35 #include <linux/spinlock.h>
  36 #include <linux/errno.h>
  37 #include <linux/usb.h>
  38 #include <linux/usb/hcd.h>
  39 #include <linux/mutex.h>
  40 #include <linux/workqueue.h>
  41 #include <linux/debugfs.h>
  42 #include <linux/usb/of.h>
  43 
  44 #include <asm/io.h>
  45 #include <linux/scatterlist.h>
  46 #include <linux/mm.h>
  47 #include <linux/dma-mapping.h>
  48 
  49 #include "hub.h"
  50 
  51 const char *usbcore_name = "usbcore";
  52 
  53 static bool nousb;      /* Disable USB when built into kernel image */
  54 
  55 module_param(nousb, bool, 0444);
  56 
  57 /*
  58  * for external read access to <nousb>
  59  */
  60 int usb_disabled(void)
  61 {
  62         return nousb;
  63 }
  64 EXPORT_SYMBOL_GPL(usb_disabled);
  65 
  66 #ifdef  CONFIG_PM
  67 /* Default delay value, in seconds */
  68 static int usb_autosuspend_delay = CONFIG_USB_AUTOSUSPEND_DELAY;
  69 module_param_named(autosuspend, usb_autosuspend_delay, int, 0644);
  70 MODULE_PARM_DESC(autosuspend, "default autosuspend delay");
  71 
  72 #else
  73 #define usb_autosuspend_delay           0
  74 #endif
  75 
  76 static bool match_endpoint(struct usb_endpoint_descriptor *epd,
  77                 struct usb_endpoint_descriptor **bulk_in,
  78                 struct usb_endpoint_descriptor **bulk_out,
  79                 struct usb_endpoint_descriptor **int_in,
  80                 struct usb_endpoint_descriptor **int_out)
  81 {
  82         switch (usb_endpoint_type(epd)) {
  83         case USB_ENDPOINT_XFER_BULK:
  84                 if (usb_endpoint_dir_in(epd)) {
  85                         if (bulk_in && !*bulk_in) {
  86                                 *bulk_in = epd;
  87                                 break;
  88                         }
  89                 } else {
  90                         if (bulk_out && !*bulk_out) {
  91                                 *bulk_out = epd;
  92                                 break;
  93                         }
  94                 }
  95 
  96                 return false;
  97         case USB_ENDPOINT_XFER_INT:
  98                 if (usb_endpoint_dir_in(epd)) {
  99                         if (int_in && !*int_in) {
 100                                 *int_in = epd;
 101                                 break;
 102                         }
 103                 } else {
 104                         if (int_out && !*int_out) {
 105                                 *int_out = epd;
 106                                 break;
 107                         }
 108                 }
 109 
 110                 return false;
 111         default:
 112                 return false;
 113         }
 114 
 115         return (!bulk_in || *bulk_in) && (!bulk_out || *bulk_out) &&
 116                         (!int_in || *int_in) && (!int_out || *int_out);
 117 }
 118 
 119 /**
 120  * usb_find_common_endpoints() -- look up common endpoint descriptors
 121  * @alt:        alternate setting to search
 122  * @bulk_in:    pointer to descriptor pointer, or NULL
 123  * @bulk_out:   pointer to descriptor pointer, or NULL
 124  * @int_in:     pointer to descriptor pointer, or NULL
 125  * @int_out:    pointer to descriptor pointer, or NULL
 126  *
 127  * Search the alternate setting's endpoint descriptors for the first bulk-in,
 128  * bulk-out, interrupt-in and interrupt-out endpoints and return them in the
 129  * provided pointers (unless they are NULL).
 130  *
 131  * If a requested endpoint is not found, the corresponding pointer is set to
 132  * NULL.
 133  *
 134  * Return: Zero if all requested descriptors were found, or -ENXIO otherwise.
 135  */
 136 int usb_find_common_endpoints(struct usb_host_interface *alt,
 137                 struct usb_endpoint_descriptor **bulk_in,
 138                 struct usb_endpoint_descriptor **bulk_out,
 139                 struct usb_endpoint_descriptor **int_in,
 140                 struct usb_endpoint_descriptor **int_out)
 141 {
 142         struct usb_endpoint_descriptor *epd;
 143         int i;
 144 
 145         if (bulk_in)
 146                 *bulk_in = NULL;
 147         if (bulk_out)
 148                 *bulk_out = NULL;
 149         if (int_in)
 150                 *int_in = NULL;
 151         if (int_out)
 152                 *int_out = NULL;
 153 
 154         for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
 155                 epd = &alt->endpoint[i].desc;
 156 
 157                 if (match_endpoint(epd, bulk_in, bulk_out, int_in, int_out))
 158                         return 0;
 159         }
 160 
 161         return -ENXIO;
 162 }
 163 EXPORT_SYMBOL_GPL(usb_find_common_endpoints);
 164 
 165 /**
 166  * usb_find_common_endpoints_reverse() -- look up common endpoint descriptors
 167  * @alt:        alternate setting to search
 168  * @bulk_in:    pointer to descriptor pointer, or NULL
 169  * @bulk_out:   pointer to descriptor pointer, or NULL
 170  * @int_in:     pointer to descriptor pointer, or NULL
 171  * @int_out:    pointer to descriptor pointer, or NULL
 172  *
 173  * Search the alternate setting's endpoint descriptors for the last bulk-in,
 174  * bulk-out, interrupt-in and interrupt-out endpoints and return them in the
 175  * provided pointers (unless they are NULL).
 176  *
 177  * If a requested endpoint is not found, the corresponding pointer is set to
 178  * NULL.
 179  *
 180  * Return: Zero if all requested descriptors were found, or -ENXIO otherwise.
 181  */
 182 int usb_find_common_endpoints_reverse(struct usb_host_interface *alt,
 183                 struct usb_endpoint_descriptor **bulk_in,
 184                 struct usb_endpoint_descriptor **bulk_out,
 185                 struct usb_endpoint_descriptor **int_in,
 186                 struct usb_endpoint_descriptor **int_out)
 187 {
 188         struct usb_endpoint_descriptor *epd;
 189         int i;
 190 
 191         if (bulk_in)
 192                 *bulk_in = NULL;
 193         if (bulk_out)
 194                 *bulk_out = NULL;
 195         if (int_in)
 196                 *int_in = NULL;
 197         if (int_out)
 198                 *int_out = NULL;
 199 
 200         for (i = alt->desc.bNumEndpoints - 1; i >= 0; --i) {
 201                 epd = &alt->endpoint[i].desc;
 202 
 203                 if (match_endpoint(epd, bulk_in, bulk_out, int_in, int_out))
 204                         return 0;
 205         }
 206 
 207         return -ENXIO;
 208 }
 209 EXPORT_SYMBOL_GPL(usb_find_common_endpoints_reverse);
 210 
 211 /**
 212  * usb_find_alt_setting() - Given a configuration, find the alternate setting
 213  * for the given interface.
 214  * @config: the configuration to search (not necessarily the current config).
 215  * @iface_num: interface number to search in
 216  * @alt_num: alternate interface setting number to search for.
 217  *
 218  * Search the configuration's interface cache for the given alt setting.
 219  *
 220  * Return: The alternate setting, if found. %NULL otherwise.
 221  */
 222 struct usb_host_interface *usb_find_alt_setting(
 223                 struct usb_host_config *config,
 224                 unsigned int iface_num,
 225                 unsigned int alt_num)
 226 {
 227         struct usb_interface_cache *intf_cache = NULL;
 228         int i;
 229 
 230         if (!config)
 231                 return NULL;
 232         for (i = 0; i < config->desc.bNumInterfaces; i++) {
 233                 if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber
 234                                 == iface_num) {
 235                         intf_cache = config->intf_cache[i];
 236                         break;
 237                 }
 238         }
 239         if (!intf_cache)
 240                 return NULL;
 241         for (i = 0; i < intf_cache->num_altsetting; i++)
 242                 if (intf_cache->altsetting[i].desc.bAlternateSetting == alt_num)
 243                         return &intf_cache->altsetting[i];
 244 
 245         printk(KERN_DEBUG "Did not find alt setting %u for intf %u, "
 246                         "config %u\n", alt_num, iface_num,
 247                         config->desc.bConfigurationValue);
 248         return NULL;
 249 }
 250 EXPORT_SYMBOL_GPL(usb_find_alt_setting);
 251 
 252 /**
 253  * usb_ifnum_to_if - get the interface object with a given interface number
 254  * @dev: the device whose current configuration is considered
 255  * @ifnum: the desired interface
 256  *
 257  * This walks the device descriptor for the currently active configuration
 258  * to find the interface object with the particular interface number.
 259  *
 260  * Note that configuration descriptors are not required to assign interface
 261  * numbers sequentially, so that it would be incorrect to assume that
 262  * the first interface in that descriptor corresponds to interface zero.
 263  * This routine helps device drivers avoid such mistakes.
 264  * However, you should make sure that you do the right thing with any
 265  * alternate settings available for this interfaces.
 266  *
 267  * Don't call this function unless you are bound to one of the interfaces
 268  * on this device or you have locked the device!
 269  *
 270  * Return: A pointer to the interface that has @ifnum as interface number,
 271  * if found. %NULL otherwise.
 272  */
 273 struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
 274                                       unsigned ifnum)
 275 {
 276         struct usb_host_config *config = dev->actconfig;
 277         int i;
 278 
 279         if (!config)
 280                 return NULL;
 281         for (i = 0; i < config->desc.bNumInterfaces; i++)
 282                 if (config->interface[i]->altsetting[0]
 283                                 .desc.bInterfaceNumber == ifnum)
 284                         return config->interface[i];
 285 
 286         return NULL;
 287 }
 288 EXPORT_SYMBOL_GPL(usb_ifnum_to_if);
 289 
 290 /**
 291  * usb_altnum_to_altsetting - get the altsetting structure with a given alternate setting number.
 292  * @intf: the interface containing the altsetting in question
 293  * @altnum: the desired alternate setting number
 294  *
 295  * This searches the altsetting array of the specified interface for
 296  * an entry with the correct bAlternateSetting value.
 297  *
 298  * Note that altsettings need not be stored sequentially by number, so
 299  * it would be incorrect to assume that the first altsetting entry in
 300  * the array corresponds to altsetting zero.  This routine helps device
 301  * drivers avoid such mistakes.
 302  *
 303  * Don't call this function unless you are bound to the intf interface
 304  * or you have locked the device!
 305  *
 306  * Return: A pointer to the entry of the altsetting array of @intf that
 307  * has @altnum as the alternate setting number. %NULL if not found.
 308  */
 309 struct usb_host_interface *usb_altnum_to_altsetting(
 310                                         const struct usb_interface *intf,
 311                                         unsigned int altnum)
 312 {
 313         int i;
 314 
 315         for (i = 0; i < intf->num_altsetting; i++) {
 316                 if (intf->altsetting[i].desc.bAlternateSetting == altnum)
 317                         return &intf->altsetting[i];
 318         }
 319         return NULL;
 320 }
 321 EXPORT_SYMBOL_GPL(usb_altnum_to_altsetting);
 322 
 323 struct find_interface_arg {
 324         int minor;
 325         struct device_driver *drv;
 326 };
 327 
 328 static int __find_interface(struct device *dev, const void *data)
 329 {
 330         const struct find_interface_arg *arg = data;
 331         struct usb_interface *intf;
 332 
 333         if (!is_usb_interface(dev))
 334                 return 0;
 335 
 336         if (dev->driver != arg->drv)
 337                 return 0;
 338         intf = to_usb_interface(dev);
 339         return intf->minor == arg->minor;
 340 }
 341 
 342 /**
 343  * usb_find_interface - find usb_interface pointer for driver and device
 344  * @drv: the driver whose current configuration is considered
 345  * @minor: the minor number of the desired device
 346  *
 347  * This walks the bus device list and returns a pointer to the interface
 348  * with the matching minor and driver.  Note, this only works for devices
 349  * that share the USB major number.
 350  *
 351  * Return: A pointer to the interface with the matching major and @minor.
 352  */
 353 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
 354 {
 355         struct find_interface_arg argb;
 356         struct device *dev;
 357 
 358         argb.minor = minor;
 359         argb.drv = &drv->drvwrap.driver;
 360 
 361         dev = bus_find_device(&usb_bus_type, NULL, &argb, __find_interface);
 362 
 363         /* Drop reference count from bus_find_device */
 364         put_device(dev);
 365 
 366         return dev ? to_usb_interface(dev) : NULL;
 367 }
 368 EXPORT_SYMBOL_GPL(usb_find_interface);
 369 
 370 struct each_dev_arg {
 371         void *data;
 372         int (*fn)(struct usb_device *, void *);
 373 };
 374 
 375 static int __each_dev(struct device *dev, void *data)
 376 {
 377         struct each_dev_arg *arg = (struct each_dev_arg *)data;
 378 
 379         /* There are struct usb_interface on the same bus, filter them out */
 380         if (!is_usb_device(dev))
 381                 return 0;
 382 
 383         return arg->fn(to_usb_device(dev), arg->data);
 384 }
 385 
 386 /**
 387  * usb_for_each_dev - iterate over all USB devices in the system
 388  * @data: data pointer that will be handed to the callback function
 389  * @fn: callback function to be called for each USB device
 390  *
 391  * Iterate over all USB devices and call @fn for each, passing it @data. If it
 392  * returns anything other than 0, we break the iteration prematurely and return
 393  * that value.
 394  */
 395 int usb_for_each_dev(void *data, int (*fn)(struct usb_device *, void *))
 396 {
 397         struct each_dev_arg arg = {data, fn};
 398 
 399         return bus_for_each_dev(&usb_bus_type, NULL, &arg, __each_dev);
 400 }
 401 EXPORT_SYMBOL_GPL(usb_for_each_dev);
 402 
 403 /**
 404  * usb_release_dev - free a usb device structure when all users of it are finished.
 405  * @dev: device that's been disconnected
 406  *
 407  * Will be called only by the device core when all users of this usb device are
 408  * done.
 409  */
 410 static void usb_release_dev(struct device *dev)
 411 {
 412         struct usb_device *udev;
 413         struct usb_hcd *hcd;
 414 
 415         udev = to_usb_device(dev);
 416         hcd = bus_to_hcd(udev->bus);
 417 
 418         usb_destroy_configuration(udev);
 419         usb_release_bos_descriptor(udev);
 420         of_node_put(dev->of_node);
 421         usb_put_hcd(hcd);
 422         kfree(udev->product);
 423         kfree(udev->manufacturer);
 424         kfree(udev->serial);
 425         kfree(udev);
 426 }
 427 
 428 static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
 429 {
 430         struct usb_device *usb_dev;
 431 
 432         usb_dev = to_usb_device(dev);
 433 
 434         if (add_uevent_var(env, "BUSNUM=%03d", usb_dev->bus->busnum))
 435                 return -ENOMEM;
 436 
 437         if (add_uevent_var(env, "DEVNUM=%03d", usb_dev->devnum))
 438                 return -ENOMEM;
 439 
 440         return 0;
 441 }
 442 
 443 #ifdef  CONFIG_PM
 444 
 445 /* USB device Power-Management thunks.
 446  * There's no need to distinguish here between quiescing a USB device
 447  * and powering it down; the generic_suspend() routine takes care of
 448  * it by skipping the usb_port_suspend() call for a quiesce.  And for
 449  * USB interfaces there's no difference at all.
 450  */
 451 
 452 static int usb_dev_prepare(struct device *dev)
 453 {
 454         return 0;               /* Implement eventually? */
 455 }
 456 
 457 static void usb_dev_complete(struct device *dev)
 458 {
 459         /* Currently used only for rebinding interfaces */
 460         usb_resume_complete(dev);
 461 }
 462 
 463 static int usb_dev_suspend(struct device *dev)
 464 {
 465         return usb_suspend(dev, PMSG_SUSPEND);
 466 }
 467 
 468 static int usb_dev_resume(struct device *dev)
 469 {
 470         return usb_resume(dev, PMSG_RESUME);
 471 }
 472 
 473 static int usb_dev_freeze(struct device *dev)
 474 {
 475         return usb_suspend(dev, PMSG_FREEZE);
 476 }
 477 
 478 static int usb_dev_thaw(struct device *dev)
 479 {
 480         return usb_resume(dev, PMSG_THAW);
 481 }
 482 
 483 static int usb_dev_poweroff(struct device *dev)
 484 {
 485         return usb_suspend(dev, PMSG_HIBERNATE);
 486 }
 487 
 488 static int usb_dev_restore(struct device *dev)
 489 {
 490         return usb_resume(dev, PMSG_RESTORE);
 491 }
 492 
 493 static const struct dev_pm_ops usb_device_pm_ops = {
 494         .prepare =      usb_dev_prepare,
 495         .complete =     usb_dev_complete,
 496         .suspend =      usb_dev_suspend,
 497         .resume =       usb_dev_resume,
 498         .freeze =       usb_dev_freeze,
 499         .thaw =         usb_dev_thaw,
 500         .poweroff =     usb_dev_poweroff,
 501         .restore =      usb_dev_restore,
 502         .runtime_suspend =      usb_runtime_suspend,
 503         .runtime_resume =       usb_runtime_resume,
 504         .runtime_idle =         usb_runtime_idle,
 505 };
 506 
 507 #endif  /* CONFIG_PM */
 508 
 509 
 510 static char *usb_devnode(struct device *dev,
 511                          umode_t *mode, kuid_t *uid, kgid_t *gid)
 512 {
 513         struct usb_device *usb_dev;
 514 
 515         usb_dev = to_usb_device(dev);
 516         return kasprintf(GFP_KERNEL, "bus/usb/%03d/%03d",
 517                          usb_dev->bus->busnum, usb_dev->devnum);
 518 }
 519 
 520 struct device_type usb_device_type = {
 521         .name =         "usb_device",
 522         .release =      usb_release_dev,
 523         .uevent =       usb_dev_uevent,
 524         .devnode =      usb_devnode,
 525 #ifdef CONFIG_PM
 526         .pm =           &usb_device_pm_ops,
 527 #endif
 528 };
 529 
 530 
 531 /* Returns 1 if @usb_bus is WUSB, 0 otherwise */
 532 static unsigned usb_bus_is_wusb(struct usb_bus *bus)
 533 {
 534         struct usb_hcd *hcd = bus_to_hcd(bus);
 535         return hcd->wireless;
 536 }
 537 
 538 static bool usb_dev_authorized(struct usb_device *dev, struct usb_hcd *hcd)
 539 {
 540         struct usb_hub *hub;
 541 
 542         if (!dev->parent)
 543                 return true; /* Root hub always ok [and always wired] */
 544 
 545         switch (hcd->dev_policy) {
 546         case USB_DEVICE_AUTHORIZE_NONE:
 547         default:
 548                 return false;
 549 
 550         case USB_DEVICE_AUTHORIZE_ALL:
 551                 return true;
 552 
 553         case USB_DEVICE_AUTHORIZE_INTERNAL:
 554                 hub = usb_hub_to_struct_hub(dev->parent);
 555                 return hub->ports[dev->portnum - 1]->connect_type ==
 556                                 USB_PORT_CONNECT_TYPE_HARD_WIRED;
 557         }
 558 }
 559 
 560 /**
 561  * usb_alloc_dev - usb device constructor (usbcore-internal)
 562  * @parent: hub to which device is connected; null to allocate a root hub
 563  * @bus: bus used to access the device
 564  * @port1: one-based index of port; ignored for root hubs
 565  * Context: !in_interrupt()
 566  *
 567  * Only hub drivers (including virtual root hub drivers for host
 568  * controllers) should ever call this.
 569  *
 570  * This call may not be used in a non-sleeping context.
 571  *
 572  * Return: On success, a pointer to the allocated usb device. %NULL on
 573  * failure.
 574  */
 575 struct usb_device *usb_alloc_dev(struct usb_device *parent,
 576                                  struct usb_bus *bus, unsigned port1)
 577 {
 578         struct usb_device *dev;
 579         struct usb_hcd *usb_hcd = bus_to_hcd(bus);
 580         unsigned root_hub = 0;
 581         unsigned raw_port = port1;
 582 
 583         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 584         if (!dev)
 585                 return NULL;
 586 
 587         if (!usb_get_hcd(usb_hcd)) {
 588                 kfree(dev);
 589                 return NULL;
 590         }
 591         /* Root hubs aren't true devices, so don't allocate HCD resources */
 592         if (usb_hcd->driver->alloc_dev && parent &&
 593                 !usb_hcd->driver->alloc_dev(usb_hcd, dev)) {
 594                 usb_put_hcd(bus_to_hcd(bus));
 595                 kfree(dev);
 596                 return NULL;
 597         }
 598 
 599         device_initialize(&dev->dev);
 600         dev->dev.bus = &usb_bus_type;
 601         dev->dev.type = &usb_device_type;
 602         dev->dev.groups = usb_device_groups;
 603         /*
 604          * Fake a dma_mask/offset for the USB device:
 605          * We cannot really use the dma-mapping API (dma_alloc_* and
 606          * dma_map_*) for USB devices but instead need to use
 607          * usb_alloc_coherent and pass data in 'urb's, but some subsystems
 608          * manually look into the mask/offset pair to determine whether
 609          * they need bounce buffers.
 610          * Note: calling dma_set_mask() on a USB device would set the
 611          * mask for the entire HCD, so don't do that.
 612          */
 613         dev->dev.dma_mask = bus->sysdev->dma_mask;
 614         dev->dev.dma_pfn_offset = bus->sysdev->dma_pfn_offset;
 615         set_dev_node(&dev->dev, dev_to_node(bus->sysdev));
 616         dev->state = USB_STATE_ATTACHED;
 617         dev->lpm_disable_count = 1;
 618         atomic_set(&dev->urbnum, 0);
 619 
 620         INIT_LIST_HEAD(&dev->ep0.urb_list);
 621         dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
 622         dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
 623         /* ep0 maxpacket comes later, from device descriptor */
 624         usb_enable_endpoint(dev, &dev->ep0, false);
 625         dev->can_submit = 1;
 626 
 627         /* Save readable and stable topology id, distinguishing devices
 628          * by location for diagnostics, tools, driver model, etc.  The
 629          * string is a path along hub ports, from the root.  Each device's
 630          * dev->devpath will be stable until USB is re-cabled, and hubs
 631          * are often labeled with these port numbers.  The name isn't
 632          * as stable:  bus->busnum changes easily from modprobe order,
 633          * cardbus or pci hotplugging, and so on.
 634          */
 635         if (unlikely(!parent)) {
 636                 dev->devpath[0] = '0';
 637                 dev->route = 0;
 638 
 639                 dev->dev.parent = bus->controller;
 640                 device_set_of_node_from_dev(&dev->dev, bus->sysdev);
 641                 dev_set_name(&dev->dev, "usb%d", bus->busnum);
 642                 root_hub = 1;
 643         } else {
 644                 /* match any labeling on the hubs; it's one-based */
 645                 if (parent->devpath[0] == '0') {
 646                         snprintf(dev->devpath, sizeof dev->devpath,
 647                                 "%d", port1);
 648                         /* Root ports are not counted in route string */
 649                         dev->route = 0;
 650                 } else {
 651                         snprintf(dev->devpath, sizeof dev->devpath,
 652                                 "%s.%d", parent->devpath, port1);
 653                         /* Route string assumes hubs have less than 16 ports */
 654                         if (port1 < 15)
 655                                 dev->route = parent->route +
 656                                         (port1 << ((parent->level - 1)*4));
 657                         else
 658                                 dev->route = parent->route +
 659                                         (15 << ((parent->level - 1)*4));
 660                 }
 661 
 662                 dev->dev.parent = &parent->dev;
 663                 dev_set_name(&dev->dev, "%d-%s", bus->busnum, dev->devpath);
 664 
 665                 if (!parent->parent) {
 666                         /* device under root hub's port */
 667                         raw_port = usb_hcd_find_raw_port_number(usb_hcd,
 668                                 port1);
 669                 }
 670                 dev->dev.of_node = usb_of_get_device_node(parent, raw_port);
 671 
 672                 /* hub driver sets up TT records */
 673         }
 674 
 675         dev->portnum = port1;
 676         dev->bus = bus;
 677         dev->parent = parent;
 678         INIT_LIST_HEAD(&dev->filelist);
 679 
 680 #ifdef  CONFIG_PM
 681         pm_runtime_set_autosuspend_delay(&dev->dev,
 682                         usb_autosuspend_delay * 1000);
 683         dev->connect_time = jiffies;
 684         dev->active_duration = -jiffies;
 685 #endif
 686 
 687         dev->authorized = usb_dev_authorized(dev, usb_hcd);
 688         if (!root_hub)
 689                 dev->wusb = usb_bus_is_wusb(bus) ? 1 : 0;
 690 
 691         return dev;
 692 }
 693 EXPORT_SYMBOL_GPL(usb_alloc_dev);
 694 
 695 /**
 696  * usb_get_dev - increments the reference count of the usb device structure
 697  * @dev: the device being referenced
 698  *
 699  * Each live reference to a device should be refcounted.
 700  *
 701  * Drivers for USB interfaces should normally record such references in
 702  * their probe() methods, when they bind to an interface, and release
 703  * them by calling usb_put_dev(), in their disconnect() methods.
 704  *
 705  * Return: A pointer to the device with the incremented reference counter.
 706  */
 707 struct usb_device *usb_get_dev(struct usb_device *dev)
 708 {
 709         if (dev)
 710                 get_device(&dev->dev);
 711         return dev;
 712 }
 713 EXPORT_SYMBOL_GPL(usb_get_dev);
 714 
 715 /**
 716  * usb_put_dev - release a use of the usb device structure
 717  * @dev: device that's been disconnected
 718  *
 719  * Must be called when a user of a device is finished with it.  When the last
 720  * user of the device calls this function, the memory of the device is freed.
 721  */
 722 void usb_put_dev(struct usb_device *dev)
 723 {
 724         if (dev)
 725                 put_device(&dev->dev);
 726 }
 727 EXPORT_SYMBOL_GPL(usb_put_dev);
 728 
 729 /**
 730  * usb_get_intf - increments the reference count of the usb interface structure
 731  * @intf: the interface being referenced
 732  *
 733  * Each live reference to a interface must be refcounted.
 734  *
 735  * Drivers for USB interfaces should normally record such references in
 736  * their probe() methods, when they bind to an interface, and release
 737  * them by calling usb_put_intf(), in their disconnect() methods.
 738  *
 739  * Return: A pointer to the interface with the incremented reference counter.
 740  */
 741 struct usb_interface *usb_get_intf(struct usb_interface *intf)
 742 {
 743         if (intf)
 744                 get_device(&intf->dev);
 745         return intf;
 746 }
 747 EXPORT_SYMBOL_GPL(usb_get_intf);
 748 
 749 /**
 750  * usb_put_intf - release a use of the usb interface structure
 751  * @intf: interface that's been decremented
 752  *
 753  * Must be called when a user of an interface is finished with it.  When the
 754  * last user of the interface calls this function, the memory of the interface
 755  * is freed.
 756  */
 757 void usb_put_intf(struct usb_interface *intf)
 758 {
 759         if (intf)
 760                 put_device(&intf->dev);
 761 }
 762 EXPORT_SYMBOL_GPL(usb_put_intf);
 763 
 764 /*                      USB device locking
 765  *
 766  * USB devices and interfaces are locked using the semaphore in their
 767  * embedded struct device.  The hub driver guarantees that whenever a
 768  * device is connected or disconnected, drivers are called with the
 769  * USB device locked as well as their particular interface.
 770  *
 771  * Complications arise when several devices are to be locked at the same
 772  * time.  Only hub-aware drivers that are part of usbcore ever have to
 773  * do this; nobody else needs to worry about it.  The rule for locking
 774  * is simple:
 775  *
 776  *      When locking both a device and its parent, always lock the
 777  *      the parent first.
 778  */
 779 
 780 /**
 781  * usb_lock_device_for_reset - cautiously acquire the lock for a usb device structure
 782  * @udev: device that's being locked
 783  * @iface: interface bound to the driver making the request (optional)
 784  *
 785  * Attempts to acquire the device lock, but fails if the device is
 786  * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
 787  * is neither BINDING nor BOUND.  Rather than sleeping to wait for the
 788  * lock, the routine polls repeatedly.  This is to prevent deadlock with
 789  * disconnect; in some drivers (such as usb-storage) the disconnect()
 790  * or suspend() method will block waiting for a device reset to complete.
 791  *
 792  * Return: A negative error code for failure, otherwise 0.
 793  */
 794 int usb_lock_device_for_reset(struct usb_device *udev,
 795                               const struct usb_interface *iface)
 796 {
 797         unsigned long jiffies_expire = jiffies + HZ;
 798 
 799         if (udev->state == USB_STATE_NOTATTACHED)
 800                 return -ENODEV;
 801         if (udev->state == USB_STATE_SUSPENDED)
 802                 return -EHOSTUNREACH;
 803         if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
 804                         iface->condition == USB_INTERFACE_UNBOUND))
 805                 return -EINTR;
 806 
 807         while (!usb_trylock_device(udev)) {
 808 
 809                 /* If we can't acquire the lock after waiting one second,
 810                  * we're probably deadlocked */
 811                 if (time_after(jiffies, jiffies_expire))
 812                         return -EBUSY;
 813 
 814                 msleep(15);
 815                 if (udev->state == USB_STATE_NOTATTACHED)
 816                         return -ENODEV;
 817                 if (udev->state == USB_STATE_SUSPENDED)
 818                         return -EHOSTUNREACH;
 819                 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
 820                                 iface->condition == USB_INTERFACE_UNBOUND))
 821                         return -EINTR;
 822         }
 823         return 0;
 824 }
 825 EXPORT_SYMBOL_GPL(usb_lock_device_for_reset);
 826 
 827 /**
 828  * usb_get_current_frame_number - return current bus frame number
 829  * @dev: the device whose bus is being queried
 830  *
 831  * Return: The current frame number for the USB host controller used
 832  * with the given USB device. This can be used when scheduling
 833  * isochronous requests.
 834  *
 835  * Note: Different kinds of host controller have different "scheduling
 836  * horizons". While one type might support scheduling only 32 frames
 837  * into the future, others could support scheduling up to 1024 frames
 838  * into the future.
 839  *
 840  */
 841 int usb_get_current_frame_number(struct usb_device *dev)
 842 {
 843         return usb_hcd_get_frame_number(dev);
 844 }
 845 EXPORT_SYMBOL_GPL(usb_get_current_frame_number);
 846 
 847 /*-------------------------------------------------------------------*/
 848 /*
 849  * __usb_get_extra_descriptor() finds a descriptor of specific type in the
 850  * extra field of the interface and endpoint descriptor structs.
 851  */
 852 
 853 int __usb_get_extra_descriptor(char *buffer, unsigned size,
 854                                unsigned char type, void **ptr, size_t minsize)
 855 {
 856         struct usb_descriptor_header *header;
 857 
 858         while (size >= sizeof(struct usb_descriptor_header)) {
 859                 header = (struct usb_descriptor_header *)buffer;
 860 
 861                 if (header->bLength < 2 || header->bLength > size) {
 862                         printk(KERN_ERR
 863                                 "%s: bogus descriptor, type %d length %d\n",
 864                                 usbcore_name,
 865                                 header->bDescriptorType,
 866                                 header->bLength);
 867                         return -1;
 868                 }
 869 
 870                 if (header->bDescriptorType == type && header->bLength >= minsize) {
 871                         *ptr = header;
 872                         return 0;
 873                 }
 874 
 875                 buffer += header->bLength;
 876                 size -= header->bLength;
 877         }
 878         return -1;
 879 }
 880 EXPORT_SYMBOL_GPL(__usb_get_extra_descriptor);
 881 
 882 /**
 883  * usb_alloc_coherent - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
 884  * @dev: device the buffer will be used with
 885  * @size: requested buffer size
 886  * @mem_flags: affect whether allocation may block
 887  * @dma: used to return DMA address of buffer
 888  *
 889  * Return: Either null (indicating no buffer could be allocated), or the
 890  * cpu-space pointer to a buffer that may be used to perform DMA to the
 891  * specified device.  Such cpu-space buffers are returned along with the DMA
 892  * address (through the pointer provided).
 893  *
 894  * Note:
 895  * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
 896  * to avoid behaviors like using "DMA bounce buffers", or thrashing IOMMU
 897  * hardware during URB completion/resubmit.  The implementation varies between
 898  * platforms, depending on details of how DMA will work to this device.
 899  * Using these buffers also eliminates cacheline sharing problems on
 900  * architectures where CPU caches are not DMA-coherent.  On systems without
 901  * bus-snooping caches, these buffers are uncached.
 902  *
 903  * When the buffer is no longer used, free it with usb_free_coherent().
 904  */
 905 void *usb_alloc_coherent(struct usb_device *dev, size_t size, gfp_t mem_flags,
 906                          dma_addr_t *dma)
 907 {
 908         if (!dev || !dev->bus)
 909                 return NULL;
 910         return hcd_buffer_alloc(dev->bus, size, mem_flags, dma);
 911 }
 912 EXPORT_SYMBOL_GPL(usb_alloc_coherent);
 913 
 914 /**
 915  * usb_free_coherent - free memory allocated with usb_alloc_coherent()
 916  * @dev: device the buffer was used with
 917  * @size: requested buffer size
 918  * @addr: CPU address of buffer
 919  * @dma: DMA address of buffer
 920  *
 921  * This reclaims an I/O buffer, letting it be reused.  The memory must have
 922  * been allocated using usb_alloc_coherent(), and the parameters must match
 923  * those provided in that allocation request.
 924  */
 925 void usb_free_coherent(struct usb_device *dev, size_t size, void *addr,
 926                        dma_addr_t dma)
 927 {
 928         if (!dev || !dev->bus)
 929                 return;
 930         if (!addr)
 931                 return;
 932         hcd_buffer_free(dev->bus, size, addr, dma);
 933 }
 934 EXPORT_SYMBOL_GPL(usb_free_coherent);
 935 
 936 /*
 937  * Notifications of device and interface registration
 938  */
 939 static int usb_bus_notify(struct notifier_block *nb, unsigned long action,
 940                 void *data)
 941 {
 942         struct device *dev = data;
 943 
 944         switch (action) {
 945         case BUS_NOTIFY_ADD_DEVICE:
 946                 if (dev->type == &usb_device_type)
 947                         (void) usb_create_sysfs_dev_files(to_usb_device(dev));
 948                 else if (dev->type == &usb_if_device_type)
 949                         usb_create_sysfs_intf_files(to_usb_interface(dev));
 950                 break;
 951 
 952         case BUS_NOTIFY_DEL_DEVICE:
 953                 if (dev->type == &usb_device_type)
 954                         usb_remove_sysfs_dev_files(to_usb_device(dev));
 955                 else if (dev->type == &usb_if_device_type)
 956                         usb_remove_sysfs_intf_files(to_usb_interface(dev));
 957                 break;
 958         }
 959         return 0;
 960 }
 961 
 962 static struct notifier_block usb_bus_nb = {
 963         .notifier_call = usb_bus_notify,
 964 };
 965 
 966 static struct dentry *usb_devices_root;
 967 
 968 static void usb_debugfs_init(void)
 969 {
 970         usb_devices_root = debugfs_create_file("devices", 0444, usb_debug_root,
 971                                                NULL, &usbfs_devices_fops);
 972 }
 973 
 974 static void usb_debugfs_cleanup(void)
 975 {
 976         debugfs_remove(usb_devices_root);
 977 }
 978 
 979 /*
 980  * Init
 981  */
 982 static int __init usb_init(void)
 983 {
 984         int retval;
 985         if (usb_disabled()) {
 986                 pr_info("%s: USB support disabled\n", usbcore_name);
 987                 return 0;
 988         }
 989         usb_init_pool_max();
 990 
 991         usb_debugfs_init();
 992 
 993         usb_acpi_register();
 994         retval = bus_register(&usb_bus_type);
 995         if (retval)
 996                 goto bus_register_failed;
 997         retval = bus_register_notifier(&usb_bus_type, &usb_bus_nb);
 998         if (retval)
 999                 goto bus_notifier_failed;
1000         retval = usb_major_init();
1001         if (retval)
1002                 goto major_init_failed;
1003         retval = usb_register(&usbfs_driver);
1004         if (retval)
1005                 goto driver_register_failed;
1006         retval = usb_devio_init();
1007         if (retval)
1008                 goto usb_devio_init_failed;
1009         retval = usb_hub_init();
1010         if (retval)
1011                 goto hub_init_failed;
1012         retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
1013         if (!retval)
1014                 goto out;
1015 
1016         usb_hub_cleanup();
1017 hub_init_failed:
1018         usb_devio_cleanup();
1019 usb_devio_init_failed:
1020         usb_deregister(&usbfs_driver);
1021 driver_register_failed:
1022         usb_major_cleanup();
1023 major_init_failed:
1024         bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1025 bus_notifier_failed:
1026         bus_unregister(&usb_bus_type);
1027 bus_register_failed:
1028         usb_acpi_unregister();
1029         usb_debugfs_cleanup();
1030 out:
1031         return retval;
1032 }
1033 
1034 /*
1035  * Cleanup
1036  */
1037 static void __exit usb_exit(void)
1038 {
1039         /* This will matter if shutdown/reboot does exitcalls. */
1040         if (usb_disabled())
1041                 return;
1042 
1043         usb_release_quirk_list();
1044         usb_deregister_device_driver(&usb_generic_driver);
1045         usb_major_cleanup();
1046         usb_deregister(&usbfs_driver);
1047         usb_devio_cleanup();
1048         usb_hub_cleanup();
1049         bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1050         bus_unregister(&usb_bus_type);
1051         usb_acpi_unregister();
1052         usb_debugfs_cleanup();
1053         idr_destroy(&usb_bus_idr);
1054 }
1055 
1056 subsys_initcall(usb_init);
1057 module_exit(usb_exit);
1058 MODULE_LICENSE("GPL");