1 // SPDX-License-Identifier: GPL-2.0
3 * drivers/usb/core/usb.c
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
16 * Released under the GPLv2 only.
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..
22 * Think of this as a "USB library" rather than anything else,
23 * with no callbacks. Callbacks are evil.
26 #include <linux/module.h>
27 #include <linux/moduleparam.h>
28 #include <linux/string.h>
29 #include <linux/bitops.h>
30 #include <linux/slab.h>
31 #include <linux/kmod.h>
32 #include <linux/init.h>
33 #include <linux/spinlock.h>
34 #include <linux/errno.h>
35 #include <linux/usb.h>
36 #include <linux/usb/hcd.h>
37 #include <linux/mutex.h>
38 #include <linux/workqueue.h>
39 #include <linux/debugfs.h>
40 #include <linux/usb/of.h>
43 #include <linux/scatterlist.h>
45 #include <linux/dma-mapping.h>
49 const char *usbcore_name = "usbcore";
51 static bool nousb; /* Disable USB when built into kernel image */
53 module_param(nousb, bool, 0444);
56 * for external read access to <nousb>
58 int usb_disabled(void)
62 EXPORT_SYMBOL_GPL(usb_disabled);
65 /* Default delay value, in seconds */
66 static int usb_autosuspend_delay = CONFIG_USB_AUTOSUSPEND_DELAY;
67 module_param_named(autosuspend, usb_autosuspend_delay, int, 0644);
68 MODULE_PARM_DESC(autosuspend, "default autosuspend delay");
71 #define usb_autosuspend_delay 0
74 static bool match_endpoint(struct usb_endpoint_descriptor *epd,
75 struct usb_endpoint_descriptor **bulk_in,
76 struct usb_endpoint_descriptor **bulk_out,
77 struct usb_endpoint_descriptor **int_in,
78 struct usb_endpoint_descriptor **int_out)
80 switch (usb_endpoint_type(epd)) {
81 case USB_ENDPOINT_XFER_BULK:
82 if (usb_endpoint_dir_in(epd)) {
83 if (bulk_in && !*bulk_in) {
88 if (bulk_out && !*bulk_out) {
95 case USB_ENDPOINT_XFER_INT:
96 if (usb_endpoint_dir_in(epd)) {
97 if (int_in && !*int_in) {
102 if (int_out && !*int_out) {
113 return (!bulk_in || *bulk_in) && (!bulk_out || *bulk_out) &&
114 (!int_in || *int_in) && (!int_out || *int_out);
118 * usb_find_common_endpoints() -- look up common endpoint descriptors
119 * @alt: alternate setting to search
120 * @bulk_in: pointer to descriptor pointer, or NULL
121 * @bulk_out: pointer to descriptor pointer, or NULL
122 * @int_in: pointer to descriptor pointer, or NULL
123 * @int_out: pointer to descriptor pointer, or NULL
125 * Search the alternate setting's endpoint descriptors for the first bulk-in,
126 * bulk-out, interrupt-in and interrupt-out endpoints and return them in the
127 * provided pointers (unless they are NULL).
129 * If a requested endpoint is not found, the corresponding pointer is set to
132 * Return: Zero if all requested descriptors were found, or -ENXIO otherwise.
134 int usb_find_common_endpoints(struct usb_host_interface *alt,
135 struct usb_endpoint_descriptor **bulk_in,
136 struct usb_endpoint_descriptor **bulk_out,
137 struct usb_endpoint_descriptor **int_in,
138 struct usb_endpoint_descriptor **int_out)
140 struct usb_endpoint_descriptor *epd;
152 for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
153 epd = &alt->endpoint[i].desc;
155 if (match_endpoint(epd, bulk_in, bulk_out, int_in, int_out))
161 EXPORT_SYMBOL_GPL(usb_find_common_endpoints);
164 * usb_find_common_endpoints_reverse() -- look up common endpoint descriptors
165 * @alt: alternate setting to search
166 * @bulk_in: pointer to descriptor pointer, or NULL
167 * @bulk_out: pointer to descriptor pointer, or NULL
168 * @int_in: pointer to descriptor pointer, or NULL
169 * @int_out: pointer to descriptor pointer, or NULL
171 * Search the alternate setting's endpoint descriptors for the last bulk-in,
172 * bulk-out, interrupt-in and interrupt-out endpoints and return them in the
173 * provided pointers (unless they are NULL).
175 * If a requested endpoint is not found, the corresponding pointer is set to
178 * Return: Zero if all requested descriptors were found, or -ENXIO otherwise.
180 int usb_find_common_endpoints_reverse(struct usb_host_interface *alt,
181 struct usb_endpoint_descriptor **bulk_in,
182 struct usb_endpoint_descriptor **bulk_out,
183 struct usb_endpoint_descriptor **int_in,
184 struct usb_endpoint_descriptor **int_out)
186 struct usb_endpoint_descriptor *epd;
198 for (i = alt->desc.bNumEndpoints - 1; i >= 0; --i) {
199 epd = &alt->endpoint[i].desc;
201 if (match_endpoint(epd, bulk_in, bulk_out, int_in, int_out))
207 EXPORT_SYMBOL_GPL(usb_find_common_endpoints_reverse);
210 * usb_find_alt_setting() - Given a configuration, find the alternate setting
211 * for the given interface.
212 * @config: the configuration to search (not necessarily the current config).
213 * @iface_num: interface number to search in
214 * @alt_num: alternate interface setting number to search for.
216 * Search the configuration's interface cache for the given alt setting.
218 * Return: The alternate setting, if found. %NULL otherwise.
220 struct usb_host_interface *usb_find_alt_setting(
221 struct usb_host_config *config,
222 unsigned int iface_num,
223 unsigned int alt_num)
225 struct usb_interface_cache *intf_cache = NULL;
230 for (i = 0; i < config->desc.bNumInterfaces; i++) {
231 if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber
233 intf_cache = config->intf_cache[i];
239 for (i = 0; i < intf_cache->num_altsetting; i++)
240 if (intf_cache->altsetting[i].desc.bAlternateSetting == alt_num)
241 return &intf_cache->altsetting[i];
243 printk(KERN_DEBUG "Did not find alt setting %u for intf %u, "
244 "config %u\n", alt_num, iface_num,
245 config->desc.bConfigurationValue);
248 EXPORT_SYMBOL_GPL(usb_find_alt_setting);
251 * usb_ifnum_to_if - get the interface object with a given interface number
252 * @dev: the device whose current configuration is considered
253 * @ifnum: the desired interface
255 * This walks the device descriptor for the currently active configuration
256 * to find the interface object with the particular interface number.
258 * Note that configuration descriptors are not required to assign interface
259 * numbers sequentially, so that it would be incorrect to assume that
260 * the first interface in that descriptor corresponds to interface zero.
261 * This routine helps device drivers avoid such mistakes.
262 * However, you should make sure that you do the right thing with any
263 * alternate settings available for this interfaces.
265 * Don't call this function unless you are bound to one of the interfaces
266 * on this device or you have locked the device!
268 * Return: A pointer to the interface that has @ifnum as interface number,
269 * if found. %NULL otherwise.
271 struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
274 struct usb_host_config *config = dev->actconfig;
279 for (i = 0; i < config->desc.bNumInterfaces; i++)
280 if (config->interface[i]->altsetting[0]
281 .desc.bInterfaceNumber == ifnum)
282 return config->interface[i];
286 EXPORT_SYMBOL_GPL(usb_ifnum_to_if);
289 * usb_altnum_to_altsetting - get the altsetting structure with a given alternate setting number.
290 * @intf: the interface containing the altsetting in question
291 * @altnum: the desired alternate setting number
293 * This searches the altsetting array of the specified interface for
294 * an entry with the correct bAlternateSetting value.
296 * Note that altsettings need not be stored sequentially by number, so
297 * it would be incorrect to assume that the first altsetting entry in
298 * the array corresponds to altsetting zero. This routine helps device
299 * drivers avoid such mistakes.
301 * Don't call this function unless you are bound to the intf interface
302 * or you have locked the device!
304 * Return: A pointer to the entry of the altsetting array of @intf that
305 * has @altnum as the alternate setting number. %NULL if not found.
307 struct usb_host_interface *usb_altnum_to_altsetting(
308 const struct usb_interface *intf,
313 for (i = 0; i < intf->num_altsetting; i++) {
314 if (intf->altsetting[i].desc.bAlternateSetting == altnum)
315 return &intf->altsetting[i];
319 EXPORT_SYMBOL_GPL(usb_altnum_to_altsetting);
321 struct find_interface_arg {
323 struct device_driver *drv;
326 static int __find_interface(struct device *dev, const void *data)
328 const struct find_interface_arg *arg = data;
329 struct usb_interface *intf;
331 if (!is_usb_interface(dev))
334 if (dev->driver != arg->drv)
336 intf = to_usb_interface(dev);
337 return intf->minor == arg->minor;
341 * usb_find_interface - find usb_interface pointer for driver and device
342 * @drv: the driver whose current configuration is considered
343 * @minor: the minor number of the desired device
345 * This walks the bus device list and returns a pointer to the interface
346 * with the matching minor and driver. Note, this only works for devices
347 * that share the USB major number.
349 * Return: A pointer to the interface with the matching major and @minor.
351 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
353 struct find_interface_arg argb;
357 argb.drv = &drv->drvwrap.driver;
359 dev = bus_find_device(&usb_bus_type, NULL, &argb, __find_interface);
361 /* Drop reference count from bus_find_device */
364 return dev ? to_usb_interface(dev) : NULL;
366 EXPORT_SYMBOL_GPL(usb_find_interface);
368 struct each_dev_arg {
370 int (*fn)(struct usb_device *, void *);
373 static int __each_dev(struct device *dev, void *data)
375 struct each_dev_arg *arg = (struct each_dev_arg *)data;
377 /* There are struct usb_interface on the same bus, filter them out */
378 if (!is_usb_device(dev))
381 return arg->fn(to_usb_device(dev), arg->data);
385 * usb_for_each_dev - iterate over all USB devices in the system
386 * @data: data pointer that will be handed to the callback function
387 * @fn: callback function to be called for each USB device
389 * Iterate over all USB devices and call @fn for each, passing it @data. If it
390 * returns anything other than 0, we break the iteration prematurely and return
393 int usb_for_each_dev(void *data, int (*fn)(struct usb_device *, void *))
395 struct each_dev_arg arg = {data, fn};
397 return bus_for_each_dev(&usb_bus_type, NULL, &arg, __each_dev);
399 EXPORT_SYMBOL_GPL(usb_for_each_dev);
401 struct each_hub_arg {
403 int (*fn)(struct device *, void *);
406 static int __each_hub(struct usb_device *hdev, void *data)
408 struct each_hub_arg *arg = (struct each_hub_arg *)data;
413 hub = usb_hub_to_struct_hub(hdev);
417 mutex_lock(&usb_port_peer_mutex);
419 for (i = 0; i < hdev->maxchild; i++) {
420 ret = arg->fn(&hub->ports[i]->dev, arg->data);
425 mutex_unlock(&usb_port_peer_mutex);
431 * usb_for_each_port - interate over all USB ports in the system
432 * @data: data pointer that will be handed to the callback function
433 * @fn: callback function to be called for each USB port
435 * Iterate over all USB ports and call @fn for each, passing it @data. If it
436 * returns anything other than 0, we break the iteration prematurely and return
439 int usb_for_each_port(void *data, int (*fn)(struct device *, void *))
441 struct each_hub_arg arg = {data, fn};
443 return usb_for_each_dev(&arg, __each_hub);
445 EXPORT_SYMBOL_GPL(usb_for_each_port);
448 * usb_release_dev - free a usb device structure when all users of it are finished.
449 * @dev: device that's been disconnected
451 * Will be called only by the device core when all users of this usb device are
454 static void usb_release_dev(struct device *dev)
456 struct usb_device *udev;
459 udev = to_usb_device(dev);
460 hcd = bus_to_hcd(udev->bus);
462 usb_destroy_configuration(udev);
463 usb_release_bos_descriptor(udev);
464 of_node_put(dev->of_node);
466 kfree(udev->product);
467 kfree(udev->manufacturer);
472 static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
474 struct usb_device *usb_dev;
476 usb_dev = to_usb_device(dev);
478 if (add_uevent_var(env, "BUSNUM=%03d", usb_dev->bus->busnum))
481 if (add_uevent_var(env, "DEVNUM=%03d", usb_dev->devnum))
489 /* USB device Power-Management thunks.
490 * There's no need to distinguish here between quiescing a USB device
491 * and powering it down; the generic_suspend() routine takes care of
492 * it by skipping the usb_port_suspend() call for a quiesce. And for
493 * USB interfaces there's no difference at all.
496 static int usb_dev_prepare(struct device *dev)
498 return 0; /* Implement eventually? */
501 static void usb_dev_complete(struct device *dev)
503 /* Currently used only for rebinding interfaces */
504 usb_resume_complete(dev);
507 static int usb_dev_suspend(struct device *dev)
509 return usb_suspend(dev, PMSG_SUSPEND);
512 static int usb_dev_resume(struct device *dev)
514 return usb_resume(dev, PMSG_RESUME);
517 static int usb_dev_freeze(struct device *dev)
519 return usb_suspend(dev, PMSG_FREEZE);
522 static int usb_dev_thaw(struct device *dev)
524 return usb_resume(dev, PMSG_THAW);
527 static int usb_dev_poweroff(struct device *dev)
529 return usb_suspend(dev, PMSG_HIBERNATE);
532 static int usb_dev_restore(struct device *dev)
534 return usb_resume(dev, PMSG_RESTORE);
537 static const struct dev_pm_ops usb_device_pm_ops = {
538 .prepare = usb_dev_prepare,
539 .complete = usb_dev_complete,
540 .suspend = usb_dev_suspend,
541 .resume = usb_dev_resume,
542 .freeze = usb_dev_freeze,
543 .thaw = usb_dev_thaw,
544 .poweroff = usb_dev_poweroff,
545 .restore = usb_dev_restore,
546 .runtime_suspend = usb_runtime_suspend,
547 .runtime_resume = usb_runtime_resume,
548 .runtime_idle = usb_runtime_idle,
551 #endif /* CONFIG_PM */
554 static char *usb_devnode(struct device *dev,
555 umode_t *mode, kuid_t *uid, kgid_t *gid)
557 struct usb_device *usb_dev;
559 usb_dev = to_usb_device(dev);
560 return kasprintf(GFP_KERNEL, "bus/usb/%03d/%03d",
561 usb_dev->bus->busnum, usb_dev->devnum);
564 struct device_type usb_device_type = {
565 .name = "usb_device",
566 .release = usb_release_dev,
567 .uevent = usb_dev_uevent,
568 .devnode = usb_devnode,
570 .pm = &usb_device_pm_ops,
575 /* Returns 1 if @usb_bus is WUSB, 0 otherwise */
576 static unsigned usb_bus_is_wusb(struct usb_bus *bus)
578 struct usb_hcd *hcd = bus_to_hcd(bus);
579 return hcd->wireless;
582 static bool usb_dev_authorized(struct usb_device *dev, struct usb_hcd *hcd)
587 return true; /* Root hub always ok [and always wired] */
589 switch (hcd->dev_policy) {
590 case USB_DEVICE_AUTHORIZE_NONE:
594 case USB_DEVICE_AUTHORIZE_ALL:
597 case USB_DEVICE_AUTHORIZE_INTERNAL:
598 hub = usb_hub_to_struct_hub(dev->parent);
599 return hub->ports[dev->portnum - 1]->connect_type ==
600 USB_PORT_CONNECT_TYPE_HARD_WIRED;
605 * usb_alloc_dev - usb device constructor (usbcore-internal)
606 * @parent: hub to which device is connected; null to allocate a root hub
607 * @bus: bus used to access the device
608 * @port1: one-based index of port; ignored for root hubs
610 * Context: task context, might sleep.
612 * Only hub drivers (including virtual root hub drivers for host
613 * controllers) should ever call this.
615 * This call may not be used in a non-sleeping context.
617 * Return: On success, a pointer to the allocated usb device. %NULL on
620 struct usb_device *usb_alloc_dev(struct usb_device *parent,
621 struct usb_bus *bus, unsigned port1)
623 struct usb_device *dev;
624 struct usb_hcd *usb_hcd = bus_to_hcd(bus);
625 unsigned root_hub = 0;
626 unsigned raw_port = port1;
628 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
632 if (!usb_get_hcd(usb_hcd)) {
636 /* Root hubs aren't true devices, so don't allocate HCD resources */
637 if (usb_hcd->driver->alloc_dev && parent &&
638 !usb_hcd->driver->alloc_dev(usb_hcd, dev)) {
639 usb_put_hcd(bus_to_hcd(bus));
644 device_initialize(&dev->dev);
645 dev->dev.bus = &usb_bus_type;
646 dev->dev.type = &usb_device_type;
647 dev->dev.groups = usb_device_groups;
648 set_dev_node(&dev->dev, dev_to_node(bus->sysdev));
649 dev->state = USB_STATE_ATTACHED;
650 dev->lpm_disable_count = 1;
651 atomic_set(&dev->urbnum, 0);
653 INIT_LIST_HEAD(&dev->ep0.urb_list);
654 dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
655 dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
656 /* ep0 maxpacket comes later, from device descriptor */
657 usb_enable_endpoint(dev, &dev->ep0, false);
660 /* Save readable and stable topology id, distinguishing devices
661 * by location for diagnostics, tools, driver model, etc. The
662 * string is a path along hub ports, from the root. Each device's
663 * dev->devpath will be stable until USB is re-cabled, and hubs
664 * are often labeled with these port numbers. The name isn't
665 * as stable: bus->busnum changes easily from modprobe order,
666 * cardbus or pci hotplugging, and so on.
668 if (unlikely(!parent)) {
669 dev->devpath[0] = '0';
672 dev->dev.parent = bus->controller;
673 device_set_of_node_from_dev(&dev->dev, bus->sysdev);
674 dev_set_name(&dev->dev, "usb%d", bus->busnum);
677 /* match any labeling on the hubs; it's one-based */
678 if (parent->devpath[0] == '0') {
679 snprintf(dev->devpath, sizeof dev->devpath,
681 /* Root ports are not counted in route string */
684 snprintf(dev->devpath, sizeof dev->devpath,
685 "%s.%d", parent->devpath, port1);
686 /* Route string assumes hubs have less than 16 ports */
688 dev->route = parent->route +
689 (port1 << ((parent->level - 1)*4));
691 dev->route = parent->route +
692 (15 << ((parent->level - 1)*4));
695 dev->dev.parent = &parent->dev;
696 dev_set_name(&dev->dev, "%d-%s", bus->busnum, dev->devpath);
698 if (!parent->parent) {
699 /* device under root hub's port */
700 raw_port = usb_hcd_find_raw_port_number(usb_hcd,
703 dev->dev.of_node = usb_of_get_device_node(parent, raw_port);
705 /* hub driver sets up TT records */
708 dev->portnum = port1;
710 dev->parent = parent;
711 INIT_LIST_HEAD(&dev->filelist);
714 pm_runtime_set_autosuspend_delay(&dev->dev,
715 usb_autosuspend_delay * 1000);
716 dev->connect_time = jiffies;
717 dev->active_duration = -jiffies;
720 dev->authorized = usb_dev_authorized(dev, usb_hcd);
722 dev->wusb = usb_bus_is_wusb(bus) ? 1 : 0;
726 EXPORT_SYMBOL_GPL(usb_alloc_dev);
729 * usb_get_dev - increments the reference count of the usb device structure
730 * @dev: the device being referenced
732 * Each live reference to a device should be refcounted.
734 * Drivers for USB interfaces should normally record such references in
735 * their probe() methods, when they bind to an interface, and release
736 * them by calling usb_put_dev(), in their disconnect() methods.
738 * Return: A pointer to the device with the incremented reference counter.
740 struct usb_device *usb_get_dev(struct usb_device *dev)
743 get_device(&dev->dev);
746 EXPORT_SYMBOL_GPL(usb_get_dev);
749 * usb_put_dev - release a use of the usb device structure
750 * @dev: device that's been disconnected
752 * Must be called when a user of a device is finished with it. When the last
753 * user of the device calls this function, the memory of the device is freed.
755 void usb_put_dev(struct usb_device *dev)
758 put_device(&dev->dev);
760 EXPORT_SYMBOL_GPL(usb_put_dev);
763 * usb_get_intf - increments the reference count of the usb interface structure
764 * @intf: the interface being referenced
766 * Each live reference to a interface must be refcounted.
768 * Drivers for USB interfaces should normally record such references in
769 * their probe() methods, when they bind to an interface, and release
770 * them by calling usb_put_intf(), in their disconnect() methods.
772 * Return: A pointer to the interface with the incremented reference counter.
774 struct usb_interface *usb_get_intf(struct usb_interface *intf)
777 get_device(&intf->dev);
780 EXPORT_SYMBOL_GPL(usb_get_intf);
783 * usb_put_intf - release a use of the usb interface structure
784 * @intf: interface that's been decremented
786 * Must be called when a user of an interface is finished with it. When the
787 * last user of the interface calls this function, the memory of the interface
790 void usb_put_intf(struct usb_interface *intf)
793 put_device(&intf->dev);
795 EXPORT_SYMBOL_GPL(usb_put_intf);
798 * usb_intf_get_dma_device - acquire a reference on the usb interface's DMA endpoint
799 * @intf: the usb interface
801 * While a USB device cannot perform DMA operations by itself, many USB
802 * controllers can. A call to usb_intf_get_dma_device() returns the DMA endpoint
803 * for the given USB interface, if any. The returned device structure must be
804 * released with put_device().
806 * See also usb_get_dma_device().
808 * Returns: A reference to the usb interface's DMA endpoint; or NULL if none
811 struct device *usb_intf_get_dma_device(struct usb_interface *intf)
813 struct usb_device *udev = interface_to_usbdev(intf);
814 struct device *dmadev;
819 dmadev = get_device(udev->bus->sysdev);
820 if (!dmadev || !dmadev->dma_mask) {
827 EXPORT_SYMBOL_GPL(usb_intf_get_dma_device);
829 /* USB device locking
831 * USB devices and interfaces are locked using the semaphore in their
832 * embedded struct device. The hub driver guarantees that whenever a
833 * device is connected or disconnected, drivers are called with the
834 * USB device locked as well as their particular interface.
836 * Complications arise when several devices are to be locked at the same
837 * time. Only hub-aware drivers that are part of usbcore ever have to
838 * do this; nobody else needs to worry about it. The rule for locking
841 * When locking both a device and its parent, always lock the
846 * usb_lock_device_for_reset - cautiously acquire the lock for a usb device structure
847 * @udev: device that's being locked
848 * @iface: interface bound to the driver making the request (optional)
850 * Attempts to acquire the device lock, but fails if the device is
851 * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
852 * is neither BINDING nor BOUND. Rather than sleeping to wait for the
853 * lock, the routine polls repeatedly. This is to prevent deadlock with
854 * disconnect; in some drivers (such as usb-storage) the disconnect()
855 * or suspend() method will block waiting for a device reset to complete.
857 * Return: A negative error code for failure, otherwise 0.
859 int usb_lock_device_for_reset(struct usb_device *udev,
860 const struct usb_interface *iface)
862 unsigned long jiffies_expire = jiffies + HZ;
864 if (udev->state == USB_STATE_NOTATTACHED)
866 if (udev->state == USB_STATE_SUSPENDED)
867 return -EHOSTUNREACH;
868 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
869 iface->condition == USB_INTERFACE_UNBOUND))
872 while (!usb_trylock_device(udev)) {
874 /* If we can't acquire the lock after waiting one second,
875 * we're probably deadlocked */
876 if (time_after(jiffies, jiffies_expire))
880 if (udev->state == USB_STATE_NOTATTACHED)
882 if (udev->state == USB_STATE_SUSPENDED)
883 return -EHOSTUNREACH;
884 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
885 iface->condition == USB_INTERFACE_UNBOUND))
890 EXPORT_SYMBOL_GPL(usb_lock_device_for_reset);
893 * usb_get_current_frame_number - return current bus frame number
894 * @dev: the device whose bus is being queried
896 * Return: The current frame number for the USB host controller used
897 * with the given USB device. This can be used when scheduling
898 * isochronous requests.
900 * Note: Different kinds of host controller have different "scheduling
901 * horizons". While one type might support scheduling only 32 frames
902 * into the future, others could support scheduling up to 1024 frames
906 int usb_get_current_frame_number(struct usb_device *dev)
908 return usb_hcd_get_frame_number(dev);
910 EXPORT_SYMBOL_GPL(usb_get_current_frame_number);
912 /*-------------------------------------------------------------------*/
914 * __usb_get_extra_descriptor() finds a descriptor of specific type in the
915 * extra field of the interface and endpoint descriptor structs.
918 int __usb_get_extra_descriptor(char *buffer, unsigned size,
919 unsigned char type, void **ptr, size_t minsize)
921 struct usb_descriptor_header *header;
923 while (size >= sizeof(struct usb_descriptor_header)) {
924 header = (struct usb_descriptor_header *)buffer;
926 if (header->bLength < 2 || header->bLength > size) {
928 "%s: bogus descriptor, type %d length %d\n",
930 header->bDescriptorType,
935 if (header->bDescriptorType == type && header->bLength >= minsize) {
940 buffer += header->bLength;
941 size -= header->bLength;
945 EXPORT_SYMBOL_GPL(__usb_get_extra_descriptor);
948 * usb_alloc_coherent - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
949 * @dev: device the buffer will be used with
950 * @size: requested buffer size
951 * @mem_flags: affect whether allocation may block
952 * @dma: used to return DMA address of buffer
954 * Return: Either null (indicating no buffer could be allocated), or the
955 * cpu-space pointer to a buffer that may be used to perform DMA to the
956 * specified device. Such cpu-space buffers are returned along with the DMA
957 * address (through the pointer provided).
960 * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
961 * to avoid behaviors like using "DMA bounce buffers", or thrashing IOMMU
962 * hardware during URB completion/resubmit. The implementation varies between
963 * platforms, depending on details of how DMA will work to this device.
964 * Using these buffers also eliminates cacheline sharing problems on
965 * architectures where CPU caches are not DMA-coherent. On systems without
966 * bus-snooping caches, these buffers are uncached.
968 * When the buffer is no longer used, free it with usb_free_coherent().
970 void *usb_alloc_coherent(struct usb_device *dev, size_t size, gfp_t mem_flags,
973 if (!dev || !dev->bus)
975 return hcd_buffer_alloc(dev->bus, size, mem_flags, dma);
977 EXPORT_SYMBOL_GPL(usb_alloc_coherent);
980 * usb_free_coherent - free memory allocated with usb_alloc_coherent()
981 * @dev: device the buffer was used with
982 * @size: requested buffer size
983 * @addr: CPU address of buffer
984 * @dma: DMA address of buffer
986 * This reclaims an I/O buffer, letting it be reused. The memory must have
987 * been allocated using usb_alloc_coherent(), and the parameters must match
988 * those provided in that allocation request.
990 void usb_free_coherent(struct usb_device *dev, size_t size, void *addr,
993 if (!dev || !dev->bus)
997 hcd_buffer_free(dev->bus, size, addr, dma);
999 EXPORT_SYMBOL_GPL(usb_free_coherent);
1002 * Notifications of device and interface registration
1004 static int usb_bus_notify(struct notifier_block *nb, unsigned long action,
1007 struct device *dev = data;
1010 case BUS_NOTIFY_ADD_DEVICE:
1011 if (dev->type == &usb_device_type)
1012 (void) usb_create_sysfs_dev_files(to_usb_device(dev));
1013 else if (dev->type == &usb_if_device_type)
1014 usb_create_sysfs_intf_files(to_usb_interface(dev));
1017 case BUS_NOTIFY_DEL_DEVICE:
1018 if (dev->type == &usb_device_type)
1019 usb_remove_sysfs_dev_files(to_usb_device(dev));
1020 else if (dev->type == &usb_if_device_type)
1021 usb_remove_sysfs_intf_files(to_usb_interface(dev));
1027 static struct notifier_block usb_bus_nb = {
1028 .notifier_call = usb_bus_notify,
1031 static void usb_debugfs_init(void)
1033 debugfs_create_file("devices", 0444, usb_debug_root, NULL,
1034 &usbfs_devices_fops);
1037 static void usb_debugfs_cleanup(void)
1039 debugfs_remove(debugfs_lookup("devices", usb_debug_root));
1045 static int __init usb_init(void)
1048 if (usb_disabled()) {
1049 pr_info("%s: USB support disabled\n", usbcore_name);
1052 usb_init_pool_max();
1056 usb_acpi_register();
1057 retval = bus_register(&usb_bus_type);
1059 goto bus_register_failed;
1060 retval = bus_register_notifier(&usb_bus_type, &usb_bus_nb);
1062 goto bus_notifier_failed;
1063 retval = usb_major_init();
1065 goto major_init_failed;
1066 retval = usb_register(&usbfs_driver);
1068 goto driver_register_failed;
1069 retval = usb_devio_init();
1071 goto usb_devio_init_failed;
1072 retval = usb_hub_init();
1074 goto hub_init_failed;
1075 retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
1081 usb_devio_cleanup();
1082 usb_devio_init_failed:
1083 usb_deregister(&usbfs_driver);
1084 driver_register_failed:
1085 usb_major_cleanup();
1087 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1088 bus_notifier_failed:
1089 bus_unregister(&usb_bus_type);
1090 bus_register_failed:
1091 usb_acpi_unregister();
1092 usb_debugfs_cleanup();
1100 static void __exit usb_exit(void)
1102 /* This will matter if shutdown/reboot does exitcalls. */
1106 usb_release_quirk_list();
1107 usb_deregister_device_driver(&usb_generic_driver);
1108 usb_major_cleanup();
1109 usb_deregister(&usbfs_driver);
1110 usb_devio_cleanup();
1112 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1113 bus_unregister(&usb_bus_type);
1114 usb_acpi_unregister();
1115 usb_debugfs_cleanup();
1116 idr_destroy(&usb_bus_idr);
1119 subsys_initcall(usb_init);
1120 module_exit(usb_exit);
1121 MODULE_LICENSE("GPL");