linux/drivers/usb/core/usb.c
<<
>>
Prefs
   1/*
   2 * drivers/usb/core/usb.c
   3 *
   4 * (C) Copyright Linus Torvalds 1999
   5 * (C) Copyright Johannes Erdfelt 1999-2001
   6 * (C) Copyright Andreas Gal 1999
   7 * (C) Copyright Gregory P. Smith 1999
   8 * (C) Copyright Deti Fliegl 1999 (new USB architecture)
   9 * (C) Copyright Randy Dunlap 2000
  10 * (C) Copyright David Brownell 2000-2004
  11 * (C) Copyright Yggdrasil Computing, Inc. 2000
  12 *     (usb_device_id matching changes by Adam J. Richter)
  13 * (C) Copyright Greg Kroah-Hartman 2002-2003
  14 *
  15 * NOTE! This is not actually a driver at all, rather this is
  16 * just a collection of helper routines that implement the
  17 * generic USB things that the real drivers can use..
  18 *
  19 * Think of this as a "USB library" rather than anything else.
  20 * It should be considered a slave, with no callbacks. Callbacks
  21 * are evil.
  22 */
  23
  24#include <linux/module.h>
  25#include <linux/moduleparam.h>
  26#include <linux/string.h>
  27#include <linux/bitops.h>
  28#include <linux/slab.h>
  29#include <linux/interrupt.h>  /* for in_interrupt() */
  30#include <linux/kmod.h>
  31#include <linux/init.h>
  32#include <linux/spinlock.h>
  33#include <linux/errno.h>
  34#include <linux/usb.h>
  35#include <linux/usb/hcd.h>
  36#include <linux/mutex.h>
  37#include <linux/workqueue.h>
  38#include <linux/debugfs.h>
  39
  40#include <asm/io.h>
  41#include <linux/scatterlist.h>
  42#include <linux/mm.h>
  43#include <linux/dma-mapping.h>
  44
  45#include "usb.h"
  46
  47
  48const char *usbcore_name = "usbcore";
  49
  50static bool nousb;      /* Disable USB when built into kernel image */
  51
  52#ifdef  CONFIG_PM_RUNTIME
  53static int usb_autosuspend_delay = 2;           /* Default delay value,
  54                                                 * in seconds */
  55module_param_named(autosuspend, usb_autosuspend_delay, int, 0644);
  56MODULE_PARM_DESC(autosuspend, "default autosuspend delay");
  57
  58#else
  59#define usb_autosuspend_delay           0
  60#endif
  61
  62
  63/**
  64 * usb_find_alt_setting() - Given a configuration, find the alternate setting
  65 * for the given interface.
  66 * @config: the configuration to search (not necessarily the current config).
  67 * @iface_num: interface number to search in
  68 * @alt_num: alternate interface setting number to search for.
  69 *
  70 * Search the configuration's interface cache for the given alt setting.
  71 *
  72 * Return: The alternate setting, if found. %NULL otherwise.
  73 */
  74struct usb_host_interface *usb_find_alt_setting(
  75                struct usb_host_config *config,
  76                unsigned int iface_num,
  77                unsigned int alt_num)
  78{
  79        struct usb_interface_cache *intf_cache = NULL;
  80        int i;
  81
  82        for (i = 0; i < config->desc.bNumInterfaces; i++) {
  83                if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber
  84                                == iface_num) {
  85                        intf_cache = config->intf_cache[i];
  86                        break;
  87                }
  88        }
  89        if (!intf_cache)
  90                return NULL;
  91        for (i = 0; i < intf_cache->num_altsetting; i++)
  92                if (intf_cache->altsetting[i].desc.bAlternateSetting == alt_num)
  93                        return &intf_cache->altsetting[i];
  94
  95        printk(KERN_DEBUG "Did not find alt setting %u for intf %u, "
  96                        "config %u\n", alt_num, iface_num,
  97                        config->desc.bConfigurationValue);
  98        return NULL;
  99}
 100EXPORT_SYMBOL_GPL(usb_find_alt_setting);
 101
 102/**
 103 * usb_ifnum_to_if - get the interface object with a given interface number
 104 * @dev: the device whose current configuration is considered
 105 * @ifnum: the desired interface
 106 *
 107 * This walks the device descriptor for the currently active configuration
 108 * to find the interface object with the particular interface number.
 109 *
 110 * Note that configuration descriptors are not required to assign interface
 111 * numbers sequentially, so that it would be incorrect to assume that
 112 * the first interface in that descriptor corresponds to interface zero.
 113 * This routine helps device drivers avoid such mistakes.
 114 * However, you should make sure that you do the right thing with any
 115 * alternate settings available for this interfaces.
 116 *
 117 * Don't call this function unless you are bound to one of the interfaces
 118 * on this device or you have locked the device!
 119 *
 120 * Return: A pointer to the interface that has @ifnum as interface number,
 121 * if found. %NULL otherwise.
 122 */
 123struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
 124                                      unsigned ifnum)
 125{
 126        struct usb_host_config *config = dev->actconfig;
 127        int i;
 128
 129        if (!config)
 130                return NULL;
 131        for (i = 0; i < config->desc.bNumInterfaces; i++)
 132                if (config->interface[i]->altsetting[0]
 133                                .desc.bInterfaceNumber == ifnum)
 134                        return config->interface[i];
 135
 136        return NULL;
 137}
 138EXPORT_SYMBOL_GPL(usb_ifnum_to_if);
 139
 140/**
 141 * usb_altnum_to_altsetting - get the altsetting structure with a given alternate setting number.
 142 * @intf: the interface containing the altsetting in question
 143 * @altnum: the desired alternate setting number
 144 *
 145 * This searches the altsetting array of the specified interface for
 146 * an entry with the correct bAlternateSetting value.
 147 *
 148 * Note that altsettings need not be stored sequentially by number, so
 149 * it would be incorrect to assume that the first altsetting entry in
 150 * the array corresponds to altsetting zero.  This routine helps device
 151 * drivers avoid such mistakes.
 152 *
 153 * Don't call this function unless you are bound to the intf interface
 154 * or you have locked the device!
 155 *
 156 * Return: A pointer to the entry of the altsetting array of @intf that
 157 * has @altnum as the alternate setting number. %NULL if not found.
 158 */
 159struct usb_host_interface *usb_altnum_to_altsetting(
 160                                        const struct usb_interface *intf,
 161                                        unsigned int altnum)
 162{
 163        int i;
 164
 165        for (i = 0; i < intf->num_altsetting; i++) {
 166                if (intf->altsetting[i].desc.bAlternateSetting == altnum)
 167                        return &intf->altsetting[i];
 168        }
 169        return NULL;
 170}
 171EXPORT_SYMBOL_GPL(usb_altnum_to_altsetting);
 172
 173struct find_interface_arg {
 174        int minor;
 175        struct device_driver *drv;
 176};
 177
 178static int __find_interface(struct device *dev, void *data)
 179{
 180        struct find_interface_arg *arg = data;
 181        struct usb_interface *intf;
 182
 183        if (!is_usb_interface(dev))
 184                return 0;
 185
 186        if (dev->driver != arg->drv)
 187                return 0;
 188        intf = to_usb_interface(dev);
 189        return intf->minor == arg->minor;
 190}
 191
 192/**
 193 * usb_find_interface - find usb_interface pointer for driver and device
 194 * @drv: the driver whose current configuration is considered
 195 * @minor: the minor number of the desired device
 196 *
 197 * This walks the bus device list and returns a pointer to the interface
 198 * with the matching minor and driver.  Note, this only works for devices
 199 * that share the USB major number.
 200 *
 201 * Return: A pointer to the interface with the matching major and @minor.
 202 */
 203struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
 204{
 205        struct find_interface_arg argb;
 206        struct device *dev;
 207
 208        argb.minor = minor;
 209        argb.drv = &drv->drvwrap.driver;
 210
 211        dev = bus_find_device(&usb_bus_type, NULL, &argb, __find_interface);
 212
 213        /* Drop reference count from bus_find_device */
 214        put_device(dev);
 215
 216        return dev ? to_usb_interface(dev) : NULL;
 217}
 218EXPORT_SYMBOL_GPL(usb_find_interface);
 219
 220struct each_dev_arg {
 221        void *data;
 222        int (*fn)(struct usb_device *, void *);
 223};
 224
 225static int __each_dev(struct device *dev, void *data)
 226{
 227        struct each_dev_arg *arg = (struct each_dev_arg *)data;
 228
 229        /* There are struct usb_interface on the same bus, filter them out */
 230        if (!is_usb_device(dev))
 231                return 0;
 232
 233        return arg->fn(container_of(dev, struct usb_device, dev), arg->data);
 234}
 235
 236/**
 237 * usb_for_each_dev - iterate over all USB devices in the system
 238 * @data: data pointer that will be handed to the callback function
 239 * @fn: callback function to be called for each USB device
 240 *
 241 * Iterate over all USB devices and call @fn for each, passing it @data. If it
 242 * returns anything other than 0, we break the iteration prematurely and return
 243 * that value.
 244 */
 245int usb_for_each_dev(void *data, int (*fn)(struct usb_device *, void *))
 246{
 247        struct each_dev_arg arg = {data, fn};
 248
 249        return bus_for_each_dev(&usb_bus_type, NULL, &arg, __each_dev);
 250}
 251EXPORT_SYMBOL_GPL(usb_for_each_dev);
 252
 253/**
 254 * usb_release_dev - free a usb device structure when all users of it are finished.
 255 * @dev: device that's been disconnected
 256 *
 257 * Will be called only by the device core when all users of this usb device are
 258 * done.
 259 */
 260static void usb_release_dev(struct device *dev)
 261{
 262        struct usb_device *udev;
 263        struct usb_hcd *hcd;
 264
 265        udev = to_usb_device(dev);
 266        hcd = bus_to_hcd(udev->bus);
 267
 268        usb_destroy_configuration(udev);
 269        usb_release_bos_descriptor(udev);
 270        usb_put_hcd(hcd);
 271        kfree(udev->product);
 272        kfree(udev->manufacturer);
 273        kfree(udev->serial);
 274        kfree(udev);
 275}
 276
 277static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
 278{
 279        struct usb_device *usb_dev;
 280
 281        usb_dev = to_usb_device(dev);
 282
 283        if (add_uevent_var(env, "BUSNUM=%03d", usb_dev->bus->busnum))
 284                return -ENOMEM;
 285
 286        if (add_uevent_var(env, "DEVNUM=%03d", usb_dev->devnum))
 287                return -ENOMEM;
 288
 289        return 0;
 290}
 291
 292#ifdef  CONFIG_PM
 293
 294/* USB device Power-Management thunks.
 295 * There's no need to distinguish here between quiescing a USB device
 296 * and powering it down; the generic_suspend() routine takes care of
 297 * it by skipping the usb_port_suspend() call for a quiesce.  And for
 298 * USB interfaces there's no difference at all.
 299 */
 300
 301static int usb_dev_prepare(struct device *dev)
 302{
 303        return 0;               /* Implement eventually? */
 304}
 305
 306static void usb_dev_complete(struct device *dev)
 307{
 308        /* Currently used only for rebinding interfaces */
 309        usb_resume_complete(dev);
 310}
 311
 312static int usb_dev_suspend(struct device *dev)
 313{
 314        return usb_suspend(dev, PMSG_SUSPEND);
 315}
 316
 317static int usb_dev_resume(struct device *dev)
 318{
 319        return usb_resume(dev, PMSG_RESUME);
 320}
 321
 322static int usb_dev_freeze(struct device *dev)
 323{
 324        return usb_suspend(dev, PMSG_FREEZE);
 325}
 326
 327static int usb_dev_thaw(struct device *dev)
 328{
 329        return usb_resume(dev, PMSG_THAW);
 330}
 331
 332static int usb_dev_poweroff(struct device *dev)
 333{
 334        return usb_suspend(dev, PMSG_HIBERNATE);
 335}
 336
 337static int usb_dev_restore(struct device *dev)
 338{
 339        return usb_resume(dev, PMSG_RESTORE);
 340}
 341
 342static const struct dev_pm_ops usb_device_pm_ops = {
 343        .prepare =      usb_dev_prepare,
 344        .complete =     usb_dev_complete,
 345        .suspend =      usb_dev_suspend,
 346        .resume =       usb_dev_resume,
 347        .freeze =       usb_dev_freeze,
 348        .thaw =         usb_dev_thaw,
 349        .poweroff =     usb_dev_poweroff,
 350        .restore =      usb_dev_restore,
 351#ifdef CONFIG_PM_RUNTIME
 352        .runtime_suspend =      usb_runtime_suspend,
 353        .runtime_resume =       usb_runtime_resume,
 354        .runtime_idle =         usb_runtime_idle,
 355#endif
 356};
 357
 358#endif  /* CONFIG_PM */
 359
 360
 361static char *usb_devnode(struct device *dev,
 362                         umode_t *mode, kuid_t *uid, kgid_t *gid)
 363{
 364        struct usb_device *usb_dev;
 365
 366        usb_dev = to_usb_device(dev);
 367        return kasprintf(GFP_KERNEL, "bus/usb/%03d/%03d",
 368                         usb_dev->bus->busnum, usb_dev->devnum);
 369}
 370
 371struct device_type usb_device_type = {
 372        .name =         "usb_device",
 373        .release =      usb_release_dev,
 374        .uevent =       usb_dev_uevent,
 375        .devnode =      usb_devnode,
 376#ifdef CONFIG_PM
 377        .pm =           &usb_device_pm_ops,
 378#endif
 379};
 380
 381
 382/* Returns 1 if @usb_bus is WUSB, 0 otherwise */
 383static unsigned usb_bus_is_wusb(struct usb_bus *bus)
 384{
 385        struct usb_hcd *hcd = container_of(bus, struct usb_hcd, self);
 386        return hcd->wireless;
 387}
 388
 389
 390/**
 391 * usb_alloc_dev - usb device constructor (usbcore-internal)
 392 * @parent: hub to which device is connected; null to allocate a root hub
 393 * @bus: bus used to access the device
 394 * @port1: one-based index of port; ignored for root hubs
 395 * Context: !in_interrupt()
 396 *
 397 * Only hub drivers (including virtual root hub drivers for host
 398 * controllers) should ever call this.
 399 *
 400 * This call may not be used in a non-sleeping context.
 401 *
 402 * Return: On success, a pointer to the allocated usb device. %NULL on
 403 * failure.
 404 */
 405struct usb_device *usb_alloc_dev(struct usb_device *parent,
 406                                 struct usb_bus *bus, unsigned port1)
 407{
 408        struct usb_device *dev;
 409        struct usb_hcd *usb_hcd = bus_to_hcd(bus);
 410        unsigned root_hub = 0;
 411
 412        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 413        if (!dev)
 414                return NULL;
 415
 416        if (!usb_get_hcd(usb_hcd)) {
 417                kfree(dev);
 418                return NULL;
 419        }
 420        /* Root hubs aren't true devices, so don't allocate HCD resources */
 421        if (usb_hcd->driver->alloc_dev && parent &&
 422                !usb_hcd->driver->alloc_dev(usb_hcd, dev)) {
 423                usb_put_hcd(bus_to_hcd(bus));
 424                kfree(dev);
 425                return NULL;
 426        }
 427
 428        device_initialize(&dev->dev);
 429        dev->dev.bus = &usb_bus_type;
 430        dev->dev.type = &usb_device_type;
 431        dev->dev.groups = usb_device_groups;
 432        dev->dev.dma_mask = bus->controller->dma_mask;
 433        set_dev_node(&dev->dev, dev_to_node(bus->controller));
 434        dev->state = USB_STATE_ATTACHED;
 435        dev->lpm_disable_count = 1;
 436        atomic_set(&dev->urbnum, 0);
 437
 438        INIT_LIST_HEAD(&dev->ep0.urb_list);
 439        dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
 440        dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
 441        /* ep0 maxpacket comes later, from device descriptor */
 442        usb_enable_endpoint(dev, &dev->ep0, false);
 443        dev->can_submit = 1;
 444
 445        /* Save readable and stable topology id, distinguishing devices
 446         * by location for diagnostics, tools, driver model, etc.  The
 447         * string is a path along hub ports, from the root.  Each device's
 448         * dev->devpath will be stable until USB is re-cabled, and hubs
 449         * are often labeled with these port numbers.  The name isn't
 450         * as stable:  bus->busnum changes easily from modprobe order,
 451         * cardbus or pci hotplugging, and so on.
 452         */
 453        if (unlikely(!parent)) {
 454                dev->devpath[0] = '0';
 455                dev->route = 0;
 456
 457                dev->dev.parent = bus->controller;
 458                dev_set_name(&dev->dev, "usb%d", bus->busnum);
 459                root_hub = 1;
 460        } else {
 461                /* match any labeling on the hubs; it's one-based */
 462                if (parent->devpath[0] == '0') {
 463                        snprintf(dev->devpath, sizeof dev->devpath,
 464                                "%d", port1);
 465                        /* Root ports are not counted in route string */
 466                        dev->route = 0;
 467                } else {
 468                        snprintf(dev->devpath, sizeof dev->devpath,
 469                                "%s.%d", parent->devpath, port1);
 470                        /* Route string assumes hubs have less than 16 ports */
 471                        if (port1 < 15)
 472                                dev->route = parent->route +
 473                                        (port1 << ((parent->level - 1)*4));
 474                        else
 475                                dev->route = parent->route +
 476                                        (15 << ((parent->level - 1)*4));
 477                }
 478
 479                dev->dev.parent = &parent->dev;
 480                dev_set_name(&dev->dev, "%d-%s", bus->busnum, dev->devpath);
 481
 482                /* hub driver sets up TT records */
 483        }
 484
 485        dev->portnum = port1;
 486        dev->bus = bus;
 487        dev->parent = parent;
 488        INIT_LIST_HEAD(&dev->filelist);
 489
 490#ifdef  CONFIG_PM
 491        pm_runtime_set_autosuspend_delay(&dev->dev,
 492                        usb_autosuspend_delay * 1000);
 493        dev->connect_time = jiffies;
 494        dev->active_duration = -jiffies;
 495#endif
 496        if (root_hub)   /* Root hub always ok [and always wired] */
 497                dev->authorized = 1;
 498        else {
 499                dev->authorized = usb_hcd->authorized_default;
 500                dev->wusb = usb_bus_is_wusb(bus) ? 1 : 0;
 501        }
 502        return dev;
 503}
 504EXPORT_SYMBOL_GPL(usb_alloc_dev);
 505
 506/**
 507 * usb_get_dev - increments the reference count of the usb device structure
 508 * @dev: the device being referenced
 509 *
 510 * Each live reference to a device should be refcounted.
 511 *
 512 * Drivers for USB interfaces should normally record such references in
 513 * their probe() methods, when they bind to an interface, and release
 514 * them by calling usb_put_dev(), in their disconnect() methods.
 515 *
 516 * Return: A pointer to the device with the incremented reference counter.
 517 */
 518struct usb_device *usb_get_dev(struct usb_device *dev)
 519{
 520        if (dev)
 521                get_device(&dev->dev);
 522        return dev;
 523}
 524EXPORT_SYMBOL_GPL(usb_get_dev);
 525
 526/**
 527 * usb_put_dev - release a use of the usb device structure
 528 * @dev: device that's been disconnected
 529 *
 530 * Must be called when a user of a device is finished with it.  When the last
 531 * user of the device calls this function, the memory of the device is freed.
 532 */
 533void usb_put_dev(struct usb_device *dev)
 534{
 535        if (dev)
 536                put_device(&dev->dev);
 537}
 538EXPORT_SYMBOL_GPL(usb_put_dev);
 539
 540/**
 541 * usb_get_intf - increments the reference count of the usb interface structure
 542 * @intf: the interface being referenced
 543 *
 544 * Each live reference to a interface must be refcounted.
 545 *
 546 * Drivers for USB interfaces should normally record such references in
 547 * their probe() methods, when they bind to an interface, and release
 548 * them by calling usb_put_intf(), in their disconnect() methods.
 549 *
 550 * Return: A pointer to the interface with the incremented reference counter.
 551 */
 552struct usb_interface *usb_get_intf(struct usb_interface *intf)
 553{
 554        if (intf)
 555                get_device(&intf->dev);
 556        return intf;
 557}
 558EXPORT_SYMBOL_GPL(usb_get_intf);
 559
 560/**
 561 * usb_put_intf - release a use of the usb interface structure
 562 * @intf: interface that's been decremented
 563 *
 564 * Must be called when a user of an interface is finished with it.  When the
 565 * last user of the interface calls this function, the memory of the interface
 566 * is freed.
 567 */
 568void usb_put_intf(struct usb_interface *intf)
 569{
 570        if (intf)
 571                put_device(&intf->dev);
 572}
 573EXPORT_SYMBOL_GPL(usb_put_intf);
 574
 575/*                      USB device locking
 576 *
 577 * USB devices and interfaces are locked using the semaphore in their
 578 * embedded struct device.  The hub driver guarantees that whenever a
 579 * device is connected or disconnected, drivers are called with the
 580 * USB device locked as well as their particular interface.
 581 *
 582 * Complications arise when several devices are to be locked at the same
 583 * time.  Only hub-aware drivers that are part of usbcore ever have to
 584 * do this; nobody else needs to worry about it.  The rule for locking
 585 * is simple:
 586 *
 587 *      When locking both a device and its parent, always lock the
 588 *      the parent first.
 589 */
 590
 591/**
 592 * usb_lock_device_for_reset - cautiously acquire the lock for a usb device structure
 593 * @udev: device that's being locked
 594 * @iface: interface bound to the driver making the request (optional)
 595 *
 596 * Attempts to acquire the device lock, but fails if the device is
 597 * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
 598 * is neither BINDING nor BOUND.  Rather than sleeping to wait for the
 599 * lock, the routine polls repeatedly.  This is to prevent deadlock with
 600 * disconnect; in some drivers (such as usb-storage) the disconnect()
 601 * or suspend() method will block waiting for a device reset to complete.
 602 *
 603 * Return: A negative error code for failure, otherwise 0.
 604 */
 605int usb_lock_device_for_reset(struct usb_device *udev,
 606                              const struct usb_interface *iface)
 607{
 608        unsigned long jiffies_expire = jiffies + HZ;
 609
 610        if (udev->state == USB_STATE_NOTATTACHED)
 611                return -ENODEV;
 612        if (udev->state == USB_STATE_SUSPENDED)
 613                return -EHOSTUNREACH;
 614        if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
 615                        iface->condition == USB_INTERFACE_UNBOUND))
 616                return -EINTR;
 617
 618        while (!usb_trylock_device(udev)) {
 619
 620                /* If we can't acquire the lock after waiting one second,
 621                 * we're probably deadlocked */
 622                if (time_after(jiffies, jiffies_expire))
 623                        return -EBUSY;
 624
 625                msleep(15);
 626                if (udev->state == USB_STATE_NOTATTACHED)
 627                        return -ENODEV;
 628                if (udev->state == USB_STATE_SUSPENDED)
 629                        return -EHOSTUNREACH;
 630                if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
 631                                iface->condition == USB_INTERFACE_UNBOUND))
 632                        return -EINTR;
 633        }
 634        return 0;
 635}
 636EXPORT_SYMBOL_GPL(usb_lock_device_for_reset);
 637
 638/**
 639 * usb_get_current_frame_number - return current bus frame number
 640 * @dev: the device whose bus is being queried
 641 *
 642 * Return: The current frame number for the USB host controller used
 643 * with the given USB device. This can be used when scheduling
 644 * isochronous requests.
 645 *
 646 * Note: Different kinds of host controller have different "scheduling
 647 * horizons". While one type might support scheduling only 32 frames
 648 * into the future, others could support scheduling up to 1024 frames
 649 * into the future.
 650 *
 651 */
 652int usb_get_current_frame_number(struct usb_device *dev)
 653{
 654        return usb_hcd_get_frame_number(dev);
 655}
 656EXPORT_SYMBOL_GPL(usb_get_current_frame_number);
 657
 658/*-------------------------------------------------------------------*/
 659/*
 660 * __usb_get_extra_descriptor() finds a descriptor of specific type in the
 661 * extra field of the interface and endpoint descriptor structs.
 662 */
 663
 664int __usb_get_extra_descriptor(char *buffer, unsigned size,
 665                               unsigned char type, void **ptr)
 666{
 667        struct usb_descriptor_header *header;
 668
 669        while (size >= sizeof(struct usb_descriptor_header)) {
 670                header = (struct usb_descriptor_header *)buffer;
 671
 672                if (header->bLength < 2) {
 673                        printk(KERN_ERR
 674                                "%s: bogus descriptor, type %d length %d\n",
 675                                usbcore_name,
 676                                header->bDescriptorType,
 677                                header->bLength);
 678                        return -1;
 679                }
 680
 681                if (header->bDescriptorType == type) {
 682                        *ptr = header;
 683                        return 0;
 684                }
 685
 686                buffer += header->bLength;
 687                size -= header->bLength;
 688        }
 689        return -1;
 690}
 691EXPORT_SYMBOL_GPL(__usb_get_extra_descriptor);
 692
 693/**
 694 * usb_alloc_coherent - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
 695 * @dev: device the buffer will be used with
 696 * @size: requested buffer size
 697 * @mem_flags: affect whether allocation may block
 698 * @dma: used to return DMA address of buffer
 699 *
 700 * Return: Either null (indicating no buffer could be allocated), or the
 701 * cpu-space pointer to a buffer that may be used to perform DMA to the
 702 * specified device.  Such cpu-space buffers are returned along with the DMA
 703 * address (through the pointer provided).
 704 *
 705 * Note:
 706 * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
 707 * to avoid behaviors like using "DMA bounce buffers", or thrashing IOMMU
 708 * hardware during URB completion/resubmit.  The implementation varies between
 709 * platforms, depending on details of how DMA will work to this device.
 710 * Using these buffers also eliminates cacheline sharing problems on
 711 * architectures where CPU caches are not DMA-coherent.  On systems without
 712 * bus-snooping caches, these buffers are uncached.
 713 *
 714 * When the buffer is no longer used, free it with usb_free_coherent().
 715 */
 716void *usb_alloc_coherent(struct usb_device *dev, size_t size, gfp_t mem_flags,
 717                         dma_addr_t *dma)
 718{
 719        if (!dev || !dev->bus)
 720                return NULL;
 721        return hcd_buffer_alloc(dev->bus, size, mem_flags, dma);
 722}
 723EXPORT_SYMBOL_GPL(usb_alloc_coherent);
 724
 725/**
 726 * usb_free_coherent - free memory allocated with usb_alloc_coherent()
 727 * @dev: device the buffer was used with
 728 * @size: requested buffer size
 729 * @addr: CPU address of buffer
 730 * @dma: DMA address of buffer
 731 *
 732 * This reclaims an I/O buffer, letting it be reused.  The memory must have
 733 * been allocated using usb_alloc_coherent(), and the parameters must match
 734 * those provided in that allocation request.
 735 */
 736void usb_free_coherent(struct usb_device *dev, size_t size, void *addr,
 737                       dma_addr_t dma)
 738{
 739        if (!dev || !dev->bus)
 740                return;
 741        if (!addr)
 742                return;
 743        hcd_buffer_free(dev->bus, size, addr, dma);
 744}
 745EXPORT_SYMBOL_GPL(usb_free_coherent);
 746
 747/**
 748 * usb_buffer_map - create DMA mapping(s) for an urb
 749 * @urb: urb whose transfer_buffer/setup_packet will be mapped
 750 *
 751 * URB_NO_TRANSFER_DMA_MAP is added to urb->transfer_flags if the operation
 752 * succeeds. If the device is connected to this system through a non-DMA
 753 * controller, this operation always succeeds.
 754 *
 755 * This call would normally be used for an urb which is reused, perhaps
 756 * as the target of a large periodic transfer, with usb_buffer_dmasync()
 757 * calls to synchronize memory and dma state.
 758 *
 759 * Reverse the effect of this call with usb_buffer_unmap().
 760 *
 761 * Return: Either %NULL (indicating no buffer could be mapped), or @urb.
 762 *
 763 */
 764#if 0
 765struct urb *usb_buffer_map(struct urb *urb)
 766{
 767        struct usb_bus          *bus;
 768        struct device           *controller;
 769
 770        if (!urb
 771                        || !urb->dev
 772                        || !(bus = urb->dev->bus)
 773                        || !(controller = bus->controller))
 774                return NULL;
 775
 776        if (controller->dma_mask) {
 777                urb->transfer_dma = dma_map_single(controller,
 778                        urb->transfer_buffer, urb->transfer_buffer_length,
 779                        usb_pipein(urb->pipe)
 780                                ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
 781        /* FIXME generic api broken like pci, can't report errors */
 782        /* if (urb->transfer_dma == DMA_ADDR_INVALID) return 0; */
 783        } else
 784                urb->transfer_dma = ~0;
 785        urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 786        return urb;
 787}
 788EXPORT_SYMBOL_GPL(usb_buffer_map);
 789#endif  /*  0  */
 790
 791/* XXX DISABLED, no users currently.  If you wish to re-enable this
 792 * XXX please determine whether the sync is to transfer ownership of
 793 * XXX the buffer from device to cpu or vice verse, and thusly use the
 794 * XXX appropriate _for_{cpu,device}() method.  -DaveM
 795 */
 796#if 0
 797
 798/**
 799 * usb_buffer_dmasync - synchronize DMA and CPU view of buffer(s)
 800 * @urb: urb whose transfer_buffer/setup_packet will be synchronized
 801 */
 802void usb_buffer_dmasync(struct urb *urb)
 803{
 804        struct usb_bus          *bus;
 805        struct device           *controller;
 806
 807        if (!urb
 808                        || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
 809                        || !urb->dev
 810                        || !(bus = urb->dev->bus)
 811                        || !(controller = bus->controller))
 812                return;
 813
 814        if (controller->dma_mask) {
 815                dma_sync_single_for_cpu(controller,
 816                        urb->transfer_dma, urb->transfer_buffer_length,
 817                        usb_pipein(urb->pipe)
 818                                ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
 819                if (usb_pipecontrol(urb->pipe))
 820                        dma_sync_single_for_cpu(controller,
 821                                        urb->setup_dma,
 822                                        sizeof(struct usb_ctrlrequest),
 823                                        DMA_TO_DEVICE);
 824        }
 825}
 826EXPORT_SYMBOL_GPL(usb_buffer_dmasync);
 827#endif
 828
 829/**
 830 * usb_buffer_unmap - free DMA mapping(s) for an urb
 831 * @urb: urb whose transfer_buffer will be unmapped
 832 *
 833 * Reverses the effect of usb_buffer_map().
 834 */
 835#if 0
 836void usb_buffer_unmap(struct urb *urb)
 837{
 838        struct usb_bus          *bus;
 839        struct device           *controller;
 840
 841        if (!urb
 842                        || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
 843                        || !urb->dev
 844                        || !(bus = urb->dev->bus)
 845                        || !(controller = bus->controller))
 846                return;
 847
 848        if (controller->dma_mask) {
 849                dma_unmap_single(controller,
 850                        urb->transfer_dma, urb->transfer_buffer_length,
 851                        usb_pipein(urb->pipe)
 852                                ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
 853        }
 854        urb->transfer_flags &= ~URB_NO_TRANSFER_DMA_MAP;
 855}
 856EXPORT_SYMBOL_GPL(usb_buffer_unmap);
 857#endif  /*  0  */
 858
 859#if 0
 860/**
 861 * usb_buffer_map_sg - create scatterlist DMA mapping(s) for an endpoint
 862 * @dev: device to which the scatterlist will be mapped
 863 * @is_in: mapping transfer direction
 864 * @sg: the scatterlist to map
 865 * @nents: the number of entries in the scatterlist
 866 *
 867 * Return: Either < 0 (indicating no buffers could be mapped), or the
 868 * number of DMA mapping array entries in the scatterlist.
 869 *
 870 * Note:
 871 * The caller is responsible for placing the resulting DMA addresses from
 872 * the scatterlist into URB transfer buffer pointers, and for setting the
 873 * URB_NO_TRANSFER_DMA_MAP transfer flag in each of those URBs.
 874 *
 875 * Top I/O rates come from queuing URBs, instead of waiting for each one
 876 * to complete before starting the next I/O.   This is particularly easy
 877 * to do with scatterlists.  Just allocate and submit one URB for each DMA
 878 * mapping entry returned, stopping on the first error or when all succeed.
 879 * Better yet, use the usb_sg_*() calls, which do that (and more) for you.
 880 *
 881 * This call would normally be used when translating scatterlist requests,
 882 * rather than usb_buffer_map(), since on some hardware (with IOMMUs) it
 883 * may be able to coalesce mappings for improved I/O efficiency.
 884 *
 885 * Reverse the effect of this call with usb_buffer_unmap_sg().
 886 */
 887int usb_buffer_map_sg(const struct usb_device *dev, int is_in,
 888                      struct scatterlist *sg, int nents)
 889{
 890        struct usb_bus          *bus;
 891        struct device           *controller;
 892
 893        if (!dev
 894                        || !(bus = dev->bus)
 895                        || !(controller = bus->controller)
 896                        || !controller->dma_mask)
 897                return -EINVAL;
 898
 899        /* FIXME generic api broken like pci, can't report errors */
 900        return dma_map_sg(controller, sg, nents,
 901                        is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE) ? : -ENOMEM;
 902}
 903EXPORT_SYMBOL_GPL(usb_buffer_map_sg);
 904#endif
 905
 906/* XXX DISABLED, no users currently.  If you wish to re-enable this
 907 * XXX please determine whether the sync is to transfer ownership of
 908 * XXX the buffer from device to cpu or vice verse, and thusly use the
 909 * XXX appropriate _for_{cpu,device}() method.  -DaveM
 910 */
 911#if 0
 912
 913/**
 914 * usb_buffer_dmasync_sg - synchronize DMA and CPU view of scatterlist buffer(s)
 915 * @dev: device to which the scatterlist will be mapped
 916 * @is_in: mapping transfer direction
 917 * @sg: the scatterlist to synchronize
 918 * @n_hw_ents: the positive return value from usb_buffer_map_sg
 919 *
 920 * Use this when you are re-using a scatterlist's data buffers for
 921 * another USB request.
 922 */
 923void usb_buffer_dmasync_sg(const struct usb_device *dev, int is_in,
 924                           struct scatterlist *sg, int n_hw_ents)
 925{
 926        struct usb_bus          *bus;
 927        struct device           *controller;
 928
 929        if (!dev
 930                        || !(bus = dev->bus)
 931                        || !(controller = bus->controller)
 932                        || !controller->dma_mask)
 933                return;
 934
 935        dma_sync_sg_for_cpu(controller, sg, n_hw_ents,
 936                            is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
 937}
 938EXPORT_SYMBOL_GPL(usb_buffer_dmasync_sg);
 939#endif
 940
 941#if 0
 942/**
 943 * usb_buffer_unmap_sg - free DMA mapping(s) for a scatterlist
 944 * @dev: device to which the scatterlist will be mapped
 945 * @is_in: mapping transfer direction
 946 * @sg: the scatterlist to unmap
 947 * @n_hw_ents: the positive return value from usb_buffer_map_sg
 948 *
 949 * Reverses the effect of usb_buffer_map_sg().
 950 */
 951void usb_buffer_unmap_sg(const struct usb_device *dev, int is_in,
 952                         struct scatterlist *sg, int n_hw_ents)
 953{
 954        struct usb_bus          *bus;
 955        struct device           *controller;
 956
 957        if (!dev
 958                        || !(bus = dev->bus)
 959                        || !(controller = bus->controller)
 960                        || !controller->dma_mask)
 961                return;
 962
 963        dma_unmap_sg(controller, sg, n_hw_ents,
 964                        is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
 965}
 966EXPORT_SYMBOL_GPL(usb_buffer_unmap_sg);
 967#endif
 968
 969/* To disable USB, kernel command line is 'nousb' not 'usbcore.nousb' */
 970#ifdef MODULE
 971module_param(nousb, bool, 0444);
 972#else
 973core_param(nousb, nousb, bool, 0444);
 974#endif
 975
 976/*
 977 * for external read access to <nousb>
 978 */
 979int usb_disabled(void)
 980{
 981        return nousb;
 982}
 983EXPORT_SYMBOL_GPL(usb_disabled);
 984
 985/*
 986 * Notifications of device and interface registration
 987 */
 988static int usb_bus_notify(struct notifier_block *nb, unsigned long action,
 989                void *data)
 990{
 991        struct device *dev = data;
 992
 993        switch (action) {
 994        case BUS_NOTIFY_ADD_DEVICE:
 995                if (dev->type == &usb_device_type)
 996                        (void) usb_create_sysfs_dev_files(to_usb_device(dev));
 997                else if (dev->type == &usb_if_device_type)
 998                        usb_create_sysfs_intf_files(to_usb_interface(dev));
 999                break;
1000
1001        case BUS_NOTIFY_DEL_DEVICE:
1002                if (dev->type == &usb_device_type)
1003                        usb_remove_sysfs_dev_files(to_usb_device(dev));
1004                else if (dev->type == &usb_if_device_type)
1005                        usb_remove_sysfs_intf_files(to_usb_interface(dev));
1006                break;
1007        }
1008        return 0;
1009}
1010
1011static struct notifier_block usb_bus_nb = {
1012        .notifier_call = usb_bus_notify,
1013};
1014
1015struct dentry *usb_debug_root;
1016EXPORT_SYMBOL_GPL(usb_debug_root);
1017
1018static struct dentry *usb_debug_devices;
1019
1020static int usb_debugfs_init(void)
1021{
1022        usb_debug_root = debugfs_create_dir("usb", NULL);
1023        if (!usb_debug_root)
1024                return -ENOENT;
1025
1026        usb_debug_devices = debugfs_create_file("devices", 0444,
1027                                                usb_debug_root, NULL,
1028                                                &usbfs_devices_fops);
1029        if (!usb_debug_devices) {
1030                debugfs_remove(usb_debug_root);
1031                usb_debug_root = NULL;
1032                return -ENOENT;
1033        }
1034
1035        return 0;
1036}
1037
1038static void usb_debugfs_cleanup(void)
1039{
1040        debugfs_remove(usb_debug_devices);
1041        debugfs_remove(usb_debug_root);
1042}
1043
1044/*
1045 * Init
1046 */
1047static int __init usb_init(void)
1048{
1049        int retval;
1050        if (nousb) {
1051                pr_info("%s: USB support disabled\n", usbcore_name);
1052                return 0;
1053        }
1054
1055        retval = usb_debugfs_init();
1056        if (retval)
1057                goto out;
1058
1059        usb_acpi_register();
1060        retval = bus_register(&usb_bus_type);
1061        if (retval)
1062                goto bus_register_failed;
1063        retval = bus_register_notifier(&usb_bus_type, &usb_bus_nb);
1064        if (retval)
1065                goto bus_notifier_failed;
1066        retval = usb_major_init();
1067        if (retval)
1068                goto major_init_failed;
1069        retval = usb_register(&usbfs_driver);
1070        if (retval)
1071                goto driver_register_failed;
1072        retval = usb_devio_init();
1073        if (retval)
1074                goto usb_devio_init_failed;
1075        retval = usb_hub_init();
1076        if (retval)
1077                goto hub_init_failed;
1078        retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
1079        if (!retval)
1080                goto out;
1081
1082        usb_hub_cleanup();
1083hub_init_failed:
1084        usb_devio_cleanup();
1085usb_devio_init_failed:
1086        usb_deregister(&usbfs_driver);
1087driver_register_failed:
1088        usb_major_cleanup();
1089major_init_failed:
1090        bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1091bus_notifier_failed:
1092        bus_unregister(&usb_bus_type);
1093bus_register_failed:
1094        usb_acpi_unregister();
1095        usb_debugfs_cleanup();
1096out:
1097        return retval;
1098}
1099
1100/*
1101 * Cleanup
1102 */
1103static void __exit usb_exit(void)
1104{
1105        /* This will matter if shutdown/reboot does exitcalls. */
1106        if (nousb)
1107                return;
1108
1109        usb_deregister_device_driver(&usb_generic_driver);
1110        usb_major_cleanup();
1111        usb_deregister(&usbfs_driver);
1112        usb_devio_cleanup();
1113        usb_hub_cleanup();
1114        bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1115        bus_unregister(&usb_bus_type);
1116        usb_acpi_unregister();
1117        usb_debugfs_cleanup();
1118}
1119
1120subsys_initcall(usb_init);
1121module_exit(usb_exit);
1122MODULE_LICENSE("GPL");
1123
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.