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_endpoint() - Given an endpoint address, search for the endpoint's
211 * usb_host_endpoint structure in an interface's current altsetting.
212 * @intf: the interface whose current altsetting should be searched
213 * @ep_addr: the endpoint address (number and direction) to find
215 * Search the altsetting's list of endpoints for one with the specified address.
217 * Return: Pointer to the usb_host_endpoint if found, %NULL otherwise.
219 static const struct usb_host_endpoint *usb_find_endpoint(
220 const struct usb_interface *intf, unsigned int ep_addr)
223 const struct usb_host_endpoint *ep;
225 n = intf->cur_altsetting->desc.bNumEndpoints;
226 ep = intf->cur_altsetting->endpoint;
227 for (; n > 0; (--n, ++ep)) {
228 if (ep->desc.bEndpointAddress == ep_addr)
235 * usb_check_bulk_endpoints - Check whether an interface's current altsetting
236 * contains a set of bulk endpoints with the given addresses.
237 * @intf: the interface whose current altsetting should be searched
238 * @ep_addrs: 0-terminated array of the endpoint addresses (number and
239 * direction) to look for
241 * Search for endpoints with the specified addresses and check their types.
243 * Return: %true if all the endpoints are found and are bulk, %false otherwise.
245 bool usb_check_bulk_endpoints(
246 const struct usb_interface *intf, const u8 *ep_addrs)
248 const struct usb_host_endpoint *ep;
250 for (; *ep_addrs; ++ep_addrs) {
251 ep = usb_find_endpoint(intf, *ep_addrs);
252 if (!ep || !usb_endpoint_xfer_bulk(&ep->desc))
257 EXPORT_SYMBOL_GPL(usb_check_bulk_endpoints);
260 * usb_check_int_endpoints - Check whether an interface's current altsetting
261 * contains a set of interrupt endpoints with the given addresses.
262 * @intf: the interface whose current altsetting should be searched
263 * @ep_addrs: 0-terminated array of the endpoint addresses (number and
264 * direction) to look for
266 * Search for endpoints with the specified addresses and check their types.
268 * Return: %true if all the endpoints are found and are interrupt,
271 bool usb_check_int_endpoints(
272 const struct usb_interface *intf, const u8 *ep_addrs)
274 const struct usb_host_endpoint *ep;
276 for (; *ep_addrs; ++ep_addrs) {
277 ep = usb_find_endpoint(intf, *ep_addrs);
278 if (!ep || !usb_endpoint_xfer_int(&ep->desc))
283 EXPORT_SYMBOL_GPL(usb_check_int_endpoints);
286 * usb_find_alt_setting() - Given a configuration, find the alternate setting
287 * for the given interface.
288 * @config: the configuration to search (not necessarily the current config).
289 * @iface_num: interface number to search in
290 * @alt_num: alternate interface setting number to search for.
292 * Search the configuration's interface cache for the given alt setting.
294 * Return: The alternate setting, if found. %NULL otherwise.
296 struct usb_host_interface *usb_find_alt_setting(
297 struct usb_host_config *config,
298 unsigned int iface_num,
299 unsigned int alt_num)
301 struct usb_interface_cache *intf_cache = NULL;
306 for (i = 0; i < config->desc.bNumInterfaces; i++) {
307 if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber
309 intf_cache = config->intf_cache[i];
315 for (i = 0; i < intf_cache->num_altsetting; i++)
316 if (intf_cache->altsetting[i].desc.bAlternateSetting == alt_num)
317 return &intf_cache->altsetting[i];
319 printk(KERN_DEBUG "Did not find alt setting %u for intf %u, "
320 "config %u\n", alt_num, iface_num,
321 config->desc.bConfigurationValue);
324 EXPORT_SYMBOL_GPL(usb_find_alt_setting);
327 * usb_ifnum_to_if - get the interface object with a given interface number
328 * @dev: the device whose current configuration is considered
329 * @ifnum: the desired interface
331 * This walks the device descriptor for the currently active configuration
332 * to find the interface object with the particular interface number.
334 * Note that configuration descriptors are not required to assign interface
335 * numbers sequentially, so that it would be incorrect to assume that
336 * the first interface in that descriptor corresponds to interface zero.
337 * This routine helps device drivers avoid such mistakes.
338 * However, you should make sure that you do the right thing with any
339 * alternate settings available for this interfaces.
341 * Don't call this function unless you are bound to one of the interfaces
342 * on this device or you have locked the device!
344 * Return: A pointer to the interface that has @ifnum as interface number,
345 * if found. %NULL otherwise.
347 struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
350 struct usb_host_config *config = dev->actconfig;
355 for (i = 0; i < config->desc.bNumInterfaces; i++)
356 if (config->interface[i]->altsetting[0]
357 .desc.bInterfaceNumber == ifnum)
358 return config->interface[i];
362 EXPORT_SYMBOL_GPL(usb_ifnum_to_if);
365 * usb_altnum_to_altsetting - get the altsetting structure with a given alternate setting number.
366 * @intf: the interface containing the altsetting in question
367 * @altnum: the desired alternate setting number
369 * This searches the altsetting array of the specified interface for
370 * an entry with the correct bAlternateSetting value.
372 * Note that altsettings need not be stored sequentially by number, so
373 * it would be incorrect to assume that the first altsetting entry in
374 * the array corresponds to altsetting zero. This routine helps device
375 * drivers avoid such mistakes.
377 * Don't call this function unless you are bound to the intf interface
378 * or you have locked the device!
380 * Return: A pointer to the entry of the altsetting array of @intf that
381 * has @altnum as the alternate setting number. %NULL if not found.
383 struct usb_host_interface *usb_altnum_to_altsetting(
384 const struct usb_interface *intf,
389 for (i = 0; i < intf->num_altsetting; i++) {
390 if (intf->altsetting[i].desc.bAlternateSetting == altnum)
391 return &intf->altsetting[i];
395 EXPORT_SYMBOL_GPL(usb_altnum_to_altsetting);
397 struct find_interface_arg {
399 struct device_driver *drv;
402 static int __find_interface(struct device *dev, const void *data)
404 const struct find_interface_arg *arg = data;
405 struct usb_interface *intf;
407 if (!is_usb_interface(dev))
410 if (dev->driver != arg->drv)
412 intf = to_usb_interface(dev);
413 return intf->minor == arg->minor;
417 * usb_find_interface - find usb_interface pointer for driver and device
418 * @drv: the driver whose current configuration is considered
419 * @minor: the minor number of the desired device
421 * This walks the bus device list and returns a pointer to the interface
422 * with the matching minor and driver. Note, this only works for devices
423 * that share the USB major number.
425 * Return: A pointer to the interface with the matching major and @minor.
427 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
429 struct find_interface_arg argb;
433 argb.drv = &drv->drvwrap.driver;
435 dev = bus_find_device(&usb_bus_type, NULL, &argb, __find_interface);
437 /* Drop reference count from bus_find_device */
440 return dev ? to_usb_interface(dev) : NULL;
442 EXPORT_SYMBOL_GPL(usb_find_interface);
444 struct each_dev_arg {
446 int (*fn)(struct usb_device *, void *);
449 static int __each_dev(struct device *dev, void *data)
451 struct each_dev_arg *arg = (struct each_dev_arg *)data;
453 /* There are struct usb_interface on the same bus, filter them out */
454 if (!is_usb_device(dev))
457 return arg->fn(to_usb_device(dev), arg->data);
461 * usb_for_each_dev - iterate over all USB devices in the system
462 * @data: data pointer that will be handed to the callback function
463 * @fn: callback function to be called for each USB device
465 * Iterate over all USB devices and call @fn for each, passing it @data. If it
466 * returns anything other than 0, we break the iteration prematurely and return
469 int usb_for_each_dev(void *data, int (*fn)(struct usb_device *, void *))
471 struct each_dev_arg arg = {data, fn};
473 return bus_for_each_dev(&usb_bus_type, NULL, &arg, __each_dev);
475 EXPORT_SYMBOL_GPL(usb_for_each_dev);
478 * usb_release_dev - free a usb device structure when all users of it are finished.
479 * @dev: device that's been disconnected
481 * Will be called only by the device core when all users of this usb device are
484 static void usb_release_dev(struct device *dev)
486 struct usb_device *udev;
489 udev = to_usb_device(dev);
490 hcd = bus_to_hcd(udev->bus);
492 usb_destroy_configuration(udev);
493 usb_release_bos_descriptor(udev);
494 of_node_put(dev->of_node);
496 kfree(udev->product);
497 kfree(udev->manufacturer);
502 static int usb_dev_uevent(const struct device *dev, struct kobj_uevent_env *env)
504 const struct usb_device *usb_dev;
506 usb_dev = to_usb_device(dev);
508 if (add_uevent_var(env, "BUSNUM=%03d", usb_dev->bus->busnum))
511 if (add_uevent_var(env, "DEVNUM=%03d", usb_dev->devnum))
519 /* USB device Power-Management thunks.
520 * There's no need to distinguish here between quiescing a USB device
521 * and powering it down; the generic_suspend() routine takes care of
522 * it by skipping the usb_port_suspend() call for a quiesce. And for
523 * USB interfaces there's no difference at all.
526 static int usb_dev_prepare(struct device *dev)
528 return 0; /* Implement eventually? */
531 static void usb_dev_complete(struct device *dev)
533 /* Currently used only for rebinding interfaces */
534 usb_resume_complete(dev);
537 static int usb_dev_suspend(struct device *dev)
539 return usb_suspend(dev, PMSG_SUSPEND);
542 static int usb_dev_resume(struct device *dev)
544 return usb_resume(dev, PMSG_RESUME);
547 static int usb_dev_freeze(struct device *dev)
549 return usb_suspend(dev, PMSG_FREEZE);
552 static int usb_dev_thaw(struct device *dev)
554 return usb_resume(dev, PMSG_THAW);
557 static int usb_dev_poweroff(struct device *dev)
559 return usb_suspend(dev, PMSG_HIBERNATE);
562 static int usb_dev_restore(struct device *dev)
564 return usb_resume(dev, PMSG_RESTORE);
567 static const struct dev_pm_ops usb_device_pm_ops = {
568 .prepare = usb_dev_prepare,
569 .complete = usb_dev_complete,
570 .suspend = usb_dev_suspend,
571 .resume = usb_dev_resume,
572 .freeze = usb_dev_freeze,
573 .thaw = usb_dev_thaw,
574 .poweroff = usb_dev_poweroff,
575 .restore = usb_dev_restore,
576 .runtime_suspend = usb_runtime_suspend,
577 .runtime_resume = usb_runtime_resume,
578 .runtime_idle = usb_runtime_idle,
581 #endif /* CONFIG_PM */
584 static char *usb_devnode(const struct device *dev,
585 umode_t *mode, kuid_t *uid, kgid_t *gid)
587 const struct usb_device *usb_dev;
589 usb_dev = to_usb_device(dev);
590 return kasprintf(GFP_KERNEL, "bus/usb/%03d/%03d",
591 usb_dev->bus->busnum, usb_dev->devnum);
594 struct device_type usb_device_type = {
595 .name = "usb_device",
596 .release = usb_release_dev,
597 .uevent = usb_dev_uevent,
598 .devnode = usb_devnode,
600 .pm = &usb_device_pm_ops,
605 /* Returns 1 if @usb_bus is WUSB, 0 otherwise */
606 static unsigned usb_bus_is_wusb(struct usb_bus *bus)
608 struct usb_hcd *hcd = bus_to_hcd(bus);
609 return hcd->wireless;
612 static bool usb_dev_authorized(struct usb_device *dev, struct usb_hcd *hcd)
617 return true; /* Root hub always ok [and always wired] */
619 switch (hcd->dev_policy) {
620 case USB_DEVICE_AUTHORIZE_NONE:
624 case USB_DEVICE_AUTHORIZE_ALL:
627 case USB_DEVICE_AUTHORIZE_INTERNAL:
628 hub = usb_hub_to_struct_hub(dev->parent);
629 return hub->ports[dev->portnum - 1]->connect_type ==
630 USB_PORT_CONNECT_TYPE_HARD_WIRED;
635 * usb_alloc_dev - usb device constructor (usbcore-internal)
636 * @parent: hub to which device is connected; null to allocate a root hub
637 * @bus: bus used to access the device
638 * @port1: one-based index of port; ignored for root hubs
640 * Context: task context, might sleep.
642 * Only hub drivers (including virtual root hub drivers for host
643 * controllers) should ever call this.
645 * This call may not be used in a non-sleeping context.
647 * Return: On success, a pointer to the allocated usb device. %NULL on
650 struct usb_device *usb_alloc_dev(struct usb_device *parent,
651 struct usb_bus *bus, unsigned port1)
653 struct usb_device *dev;
654 struct usb_hcd *usb_hcd = bus_to_hcd(bus);
655 unsigned root_hub = 0;
656 unsigned raw_port = port1;
658 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
662 if (!usb_get_hcd(usb_hcd)) {
666 /* Root hubs aren't true devices, so don't allocate HCD resources */
667 if (usb_hcd->driver->alloc_dev && parent &&
668 !usb_hcd->driver->alloc_dev(usb_hcd, dev)) {
669 usb_put_hcd(bus_to_hcd(bus));
674 device_initialize(&dev->dev);
675 dev->dev.bus = &usb_bus_type;
676 dev->dev.type = &usb_device_type;
677 dev->dev.groups = usb_device_groups;
678 set_dev_node(&dev->dev, dev_to_node(bus->sysdev));
679 dev->state = USB_STATE_ATTACHED;
680 dev->lpm_disable_count = 1;
681 atomic_set(&dev->urbnum, 0);
683 INIT_LIST_HEAD(&dev->ep0.urb_list);
684 dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
685 dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
686 /* ep0 maxpacket comes later, from device descriptor */
687 usb_enable_endpoint(dev, &dev->ep0, false);
690 /* Save readable and stable topology id, distinguishing devices
691 * by location for diagnostics, tools, driver model, etc. The
692 * string is a path along hub ports, from the root. Each device's
693 * dev->devpath will be stable until USB is re-cabled, and hubs
694 * are often labeled with these port numbers. The name isn't
695 * as stable: bus->busnum changes easily from modprobe order,
696 * cardbus or pci hotplugging, and so on.
698 if (unlikely(!parent)) {
699 dev->devpath[0] = '0';
702 dev->dev.parent = bus->controller;
703 device_set_of_node_from_dev(&dev->dev, bus->sysdev);
704 dev_set_name(&dev->dev, "usb%d", bus->busnum);
707 /* match any labeling on the hubs; it's one-based */
708 if (parent->devpath[0] == '0') {
709 snprintf(dev->devpath, sizeof dev->devpath,
711 /* Root ports are not counted in route string */
714 snprintf(dev->devpath, sizeof dev->devpath,
715 "%s.%d", parent->devpath, port1);
716 /* Route string assumes hubs have less than 16 ports */
718 dev->route = parent->route +
719 (port1 << ((parent->level - 1)*4));
721 dev->route = parent->route +
722 (15 << ((parent->level - 1)*4));
725 dev->dev.parent = &parent->dev;
726 dev_set_name(&dev->dev, "%d-%s", bus->busnum, dev->devpath);
728 if (!parent->parent) {
729 /* device under root hub's port */
730 raw_port = usb_hcd_find_raw_port_number(usb_hcd,
733 dev->dev.of_node = usb_of_get_device_node(parent, raw_port);
735 /* hub driver sets up TT records */
738 dev->portnum = port1;
740 dev->parent = parent;
741 INIT_LIST_HEAD(&dev->filelist);
744 pm_runtime_set_autosuspend_delay(&dev->dev,
745 usb_autosuspend_delay * 1000);
746 dev->connect_time = jiffies;
747 dev->active_duration = -jiffies;
750 dev->authorized = usb_dev_authorized(dev, usb_hcd);
752 dev->wusb = usb_bus_is_wusb(bus) ? 1 : 0;
756 EXPORT_SYMBOL_GPL(usb_alloc_dev);
759 * usb_get_dev - increments the reference count of the usb device structure
760 * @dev: the device being referenced
762 * Each live reference to a device should be refcounted.
764 * Drivers for USB interfaces should normally record such references in
765 * their probe() methods, when they bind to an interface, and release
766 * them by calling usb_put_dev(), in their disconnect() methods.
767 * However, if a driver does not access the usb_device structure after
768 * its disconnect() method returns then refcounting is not necessary,
769 * because the USB core guarantees that a usb_device will not be
770 * deallocated until after all of its interface drivers have been unbound.
772 * Return: A pointer to the device with the incremented reference counter.
774 struct usb_device *usb_get_dev(struct usb_device *dev)
777 get_device(&dev->dev);
780 EXPORT_SYMBOL_GPL(usb_get_dev);
783 * usb_put_dev - release a use of the usb device structure
784 * @dev: device that's been disconnected
786 * Must be called when a user of a device is finished with it. When the last
787 * user of the device calls this function, the memory of the device is freed.
789 void usb_put_dev(struct usb_device *dev)
792 put_device(&dev->dev);
794 EXPORT_SYMBOL_GPL(usb_put_dev);
797 * usb_get_intf - increments the reference count of the usb interface structure
798 * @intf: the interface being referenced
800 * Each live reference to a interface must be refcounted.
802 * Drivers for USB interfaces should normally record such references in
803 * their probe() methods, when they bind to an interface, and release
804 * them by calling usb_put_intf(), in their disconnect() methods.
805 * However, if a driver does not access the usb_interface structure after
806 * its disconnect() method returns then refcounting is not necessary,
807 * because the USB core guarantees that a usb_interface will not be
808 * deallocated until after its driver has been unbound.
810 * Return: A pointer to the interface with the incremented reference counter.
812 struct usb_interface *usb_get_intf(struct usb_interface *intf)
815 get_device(&intf->dev);
818 EXPORT_SYMBOL_GPL(usb_get_intf);
821 * usb_put_intf - release a use of the usb interface structure
822 * @intf: interface that's been decremented
824 * Must be called when a user of an interface is finished with it. When the
825 * last user of the interface calls this function, the memory of the interface
828 void usb_put_intf(struct usb_interface *intf)
831 put_device(&intf->dev);
833 EXPORT_SYMBOL_GPL(usb_put_intf);
836 * usb_intf_get_dma_device - acquire a reference on the usb interface's DMA endpoint
837 * @intf: the usb interface
839 * While a USB device cannot perform DMA operations by itself, many USB
840 * controllers can. A call to usb_intf_get_dma_device() returns the DMA endpoint
841 * for the given USB interface, if any. The returned device structure must be
842 * released with put_device().
844 * See also usb_get_dma_device().
846 * Returns: A reference to the usb interface's DMA endpoint; or NULL if none
849 struct device *usb_intf_get_dma_device(struct usb_interface *intf)
851 struct usb_device *udev = interface_to_usbdev(intf);
852 struct device *dmadev;
857 dmadev = get_device(udev->bus->sysdev);
858 if (!dmadev || !dmadev->dma_mask) {
865 EXPORT_SYMBOL_GPL(usb_intf_get_dma_device);
867 /* USB device locking
869 * USB devices and interfaces are locked using the semaphore in their
870 * embedded struct device. The hub driver guarantees that whenever a
871 * device is connected or disconnected, drivers are called with the
872 * USB device locked as well as their particular interface.
874 * Complications arise when several devices are to be locked at the same
875 * time. Only hub-aware drivers that are part of usbcore ever have to
876 * do this; nobody else needs to worry about it. The rule for locking
879 * When locking both a device and its parent, always lock the
884 * usb_lock_device_for_reset - cautiously acquire the lock for a usb device structure
885 * @udev: device that's being locked
886 * @iface: interface bound to the driver making the request (optional)
888 * Attempts to acquire the device lock, but fails if the device is
889 * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
890 * is neither BINDING nor BOUND. Rather than sleeping to wait for the
891 * lock, the routine polls repeatedly. This is to prevent deadlock with
892 * disconnect; in some drivers (such as usb-storage) the disconnect()
893 * or suspend() method will block waiting for a device reset to complete.
895 * Return: A negative error code for failure, otherwise 0.
897 int usb_lock_device_for_reset(struct usb_device *udev,
898 const struct usb_interface *iface)
900 unsigned long jiffies_expire = jiffies + HZ;
902 if (udev->state == USB_STATE_NOTATTACHED)
904 if (udev->state == USB_STATE_SUSPENDED)
905 return -EHOSTUNREACH;
906 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
907 iface->condition == USB_INTERFACE_UNBOUND))
910 while (!usb_trylock_device(udev)) {
912 /* If we can't acquire the lock after waiting one second,
913 * we're probably deadlocked */
914 if (time_after(jiffies, jiffies_expire))
918 if (udev->state == USB_STATE_NOTATTACHED)
920 if (udev->state == USB_STATE_SUSPENDED)
921 return -EHOSTUNREACH;
922 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
923 iface->condition == USB_INTERFACE_UNBOUND))
928 EXPORT_SYMBOL_GPL(usb_lock_device_for_reset);
931 * usb_get_current_frame_number - return current bus frame number
932 * @dev: the device whose bus is being queried
934 * Return: The current frame number for the USB host controller used
935 * with the given USB device. This can be used when scheduling
936 * isochronous requests.
938 * Note: Different kinds of host controller have different "scheduling
939 * horizons". While one type might support scheduling only 32 frames
940 * into the future, others could support scheduling up to 1024 frames
944 int usb_get_current_frame_number(struct usb_device *dev)
946 return usb_hcd_get_frame_number(dev);
948 EXPORT_SYMBOL_GPL(usb_get_current_frame_number);
950 /*-------------------------------------------------------------------*/
952 * __usb_get_extra_descriptor() finds a descriptor of specific type in the
953 * extra field of the interface and endpoint descriptor structs.
956 int __usb_get_extra_descriptor(char *buffer, unsigned size,
957 unsigned char type, void **ptr, size_t minsize)
959 struct usb_descriptor_header *header;
961 while (size >= sizeof(struct usb_descriptor_header)) {
962 header = (struct usb_descriptor_header *)buffer;
964 if (header->bLength < 2 || header->bLength > size) {
966 "%s: bogus descriptor, type %d length %d\n",
968 header->bDescriptorType,
973 if (header->bDescriptorType == type && header->bLength >= minsize) {
978 buffer += header->bLength;
979 size -= header->bLength;
983 EXPORT_SYMBOL_GPL(__usb_get_extra_descriptor);
986 * usb_alloc_coherent - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
987 * @dev: device the buffer will be used with
988 * @size: requested buffer size
989 * @mem_flags: affect whether allocation may block
990 * @dma: used to return DMA address of buffer
992 * Return: Either null (indicating no buffer could be allocated), or the
993 * cpu-space pointer to a buffer that may be used to perform DMA to the
994 * specified device. Such cpu-space buffers are returned along with the DMA
995 * address (through the pointer provided).
998 * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
999 * to avoid behaviors like using "DMA bounce buffers", or thrashing IOMMU
1000 * hardware during URB completion/resubmit. The implementation varies between
1001 * platforms, depending on details of how DMA will work to this device.
1002 * Using these buffers also eliminates cacheline sharing problems on
1003 * architectures where CPU caches are not DMA-coherent. On systems without
1004 * bus-snooping caches, these buffers are uncached.
1006 * When the buffer is no longer used, free it with usb_free_coherent().
1008 void *usb_alloc_coherent(struct usb_device *dev, size_t size, gfp_t mem_flags,
1011 if (!dev || !dev->bus)
1013 return hcd_buffer_alloc(dev->bus, size, mem_flags, dma);
1015 EXPORT_SYMBOL_GPL(usb_alloc_coherent);
1018 * usb_free_coherent - free memory allocated with usb_alloc_coherent()
1019 * @dev: device the buffer was used with
1020 * @size: requested buffer size
1021 * @addr: CPU address of buffer
1022 * @dma: DMA address of buffer
1024 * This reclaims an I/O buffer, letting it be reused. The memory must have
1025 * been allocated using usb_alloc_coherent(), and the parameters must match
1026 * those provided in that allocation request.
1028 void usb_free_coherent(struct usb_device *dev, size_t size, void *addr,
1031 if (!dev || !dev->bus)
1035 hcd_buffer_free(dev->bus, size, addr, dma);
1037 EXPORT_SYMBOL_GPL(usb_free_coherent);
1040 * Notifications of device and interface registration
1042 static int usb_bus_notify(struct notifier_block *nb, unsigned long action,
1045 struct device *dev = data;
1048 case BUS_NOTIFY_ADD_DEVICE:
1049 if (dev->type == &usb_device_type)
1050 (void) usb_create_sysfs_dev_files(to_usb_device(dev));
1051 else if (dev->type == &usb_if_device_type)
1052 usb_create_sysfs_intf_files(to_usb_interface(dev));
1055 case BUS_NOTIFY_DEL_DEVICE:
1056 if (dev->type == &usb_device_type)
1057 usb_remove_sysfs_dev_files(to_usb_device(dev));
1058 else if (dev->type == &usb_if_device_type)
1059 usb_remove_sysfs_intf_files(to_usb_interface(dev));
1065 static struct notifier_block usb_bus_nb = {
1066 .notifier_call = usb_bus_notify,
1069 static void usb_debugfs_init(void)
1071 debugfs_create_file("devices", 0444, usb_debug_root, NULL,
1072 &usbfs_devices_fops);
1075 static void usb_debugfs_cleanup(void)
1077 debugfs_lookup_and_remove("devices", usb_debug_root);
1083 static int __init usb_init(void)
1086 if (usb_disabled()) {
1087 pr_info("%s: USB support disabled\n", usbcore_name);
1090 usb_init_pool_max();
1094 usb_acpi_register();
1095 retval = bus_register(&usb_bus_type);
1097 goto bus_register_failed;
1098 retval = bus_register_notifier(&usb_bus_type, &usb_bus_nb);
1100 goto bus_notifier_failed;
1101 retval = usb_major_init();
1103 goto major_init_failed;
1104 retval = usb_register(&usbfs_driver);
1106 goto driver_register_failed;
1107 retval = usb_devio_init();
1109 goto usb_devio_init_failed;
1110 retval = usb_hub_init();
1112 goto hub_init_failed;
1113 retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
1119 usb_devio_cleanup();
1120 usb_devio_init_failed:
1121 usb_deregister(&usbfs_driver);
1122 driver_register_failed:
1123 usb_major_cleanup();
1125 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1126 bus_notifier_failed:
1127 bus_unregister(&usb_bus_type);
1128 bus_register_failed:
1129 usb_acpi_unregister();
1130 usb_debugfs_cleanup();
1138 static void __exit usb_exit(void)
1140 /* This will matter if shutdown/reboot does exitcalls. */
1144 usb_release_quirk_list();
1145 usb_deregister_device_driver(&usb_generic_driver);
1146 usb_major_cleanup();
1147 usb_deregister(&usbfs_driver);
1148 usb_devio_cleanup();
1150 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1151 bus_unregister(&usb_bus_type);
1152 usb_acpi_unregister();
1153 usb_debugfs_cleanup();
1154 idr_destroy(&usb_bus_idr);
1157 subsys_initcall(usb_init);
1158 module_exit(usb_exit);
1159 MODULE_LICENSE("GPL");