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/interrupt.h> /* for in_interrupt() */
32 #include <linux/kmod.h>
33 #include <linux/init.h>
34 #include <linux/spinlock.h>
35 #include <linux/errno.h>
36 #include <linux/usb.h>
37 #include <linux/usb/hcd.h>
38 #include <linux/mutex.h>
39 #include <linux/workqueue.h>
40 #include <linux/debugfs.h>
41 #include <linux/usb/of.h>
44 #include <linux/scatterlist.h>
46 #include <linux/dma-mapping.h>
50 const char *usbcore_name = "usbcore";
52 static bool nousb; /* Disable USB when built into kernel image */
54 module_param(nousb, bool, 0444);
57 * for external read access to <nousb>
59 int usb_disabled(void)
63 EXPORT_SYMBOL_GPL(usb_disabled);
66 /* Default delay value, in seconds */
67 static int usb_autosuspend_delay = CONFIG_USB_AUTOSUSPEND_DELAY;
68 module_param_named(autosuspend, usb_autosuspend_delay, int, 0644);
69 MODULE_PARM_DESC(autosuspend, "default autosuspend delay");
72 #define usb_autosuspend_delay 0
75 static bool match_endpoint(struct usb_endpoint_descriptor *epd,
76 struct usb_endpoint_descriptor **bulk_in,
77 struct usb_endpoint_descriptor **bulk_out,
78 struct usb_endpoint_descriptor **int_in,
79 struct usb_endpoint_descriptor **int_out)
81 switch (usb_endpoint_type(epd)) {
82 case USB_ENDPOINT_XFER_BULK:
83 if (usb_endpoint_dir_in(epd)) {
84 if (bulk_in && !*bulk_in) {
89 if (bulk_out && !*bulk_out) {
96 case USB_ENDPOINT_XFER_INT:
97 if (usb_endpoint_dir_in(epd)) {
98 if (int_in && !*int_in) {
103 if (int_out && !*int_out) {
114 return (!bulk_in || *bulk_in) && (!bulk_out || *bulk_out) &&
115 (!int_in || *int_in) && (!int_out || *int_out);
119 * usb_find_common_endpoints() -- look up common endpoint descriptors
120 * @alt: alternate setting to search
121 * @bulk_in: pointer to descriptor pointer, or NULL
122 * @bulk_out: pointer to descriptor pointer, or NULL
123 * @int_in: pointer to descriptor pointer, or NULL
124 * @int_out: pointer to descriptor pointer, or NULL
126 * Search the alternate setting's endpoint descriptors for the first bulk-in,
127 * bulk-out, interrupt-in and interrupt-out endpoints and return them in the
128 * provided pointers (unless they are NULL).
130 * If a requested endpoint is not found, the corresponding pointer is set to
133 * Return: Zero if all requested descriptors were found, or -ENXIO otherwise.
135 int usb_find_common_endpoints(struct usb_host_interface *alt,
136 struct usb_endpoint_descriptor **bulk_in,
137 struct usb_endpoint_descriptor **bulk_out,
138 struct usb_endpoint_descriptor **int_in,
139 struct usb_endpoint_descriptor **int_out)
141 struct usb_endpoint_descriptor *epd;
153 for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
154 epd = &alt->endpoint[i].desc;
156 if (match_endpoint(epd, bulk_in, bulk_out, int_in, int_out))
162 EXPORT_SYMBOL_GPL(usb_find_common_endpoints);
165 * usb_find_common_endpoints_reverse() -- look up common endpoint descriptors
166 * @alt: alternate setting to search
167 * @bulk_in: pointer to descriptor pointer, or NULL
168 * @bulk_out: pointer to descriptor pointer, or NULL
169 * @int_in: pointer to descriptor pointer, or NULL
170 * @int_out: pointer to descriptor pointer, or NULL
172 * Search the alternate setting's endpoint descriptors for the last bulk-in,
173 * bulk-out, interrupt-in and interrupt-out endpoints and return them in the
174 * provided pointers (unless they are NULL).
176 * If a requested endpoint is not found, the corresponding pointer is set to
179 * Return: Zero if all requested descriptors were found, or -ENXIO otherwise.
181 int usb_find_common_endpoints_reverse(struct usb_host_interface *alt,
182 struct usb_endpoint_descriptor **bulk_in,
183 struct usb_endpoint_descriptor **bulk_out,
184 struct usb_endpoint_descriptor **int_in,
185 struct usb_endpoint_descriptor **int_out)
187 struct usb_endpoint_descriptor *epd;
199 for (i = alt->desc.bNumEndpoints - 1; i >= 0; --i) {
200 epd = &alt->endpoint[i].desc;
202 if (match_endpoint(epd, bulk_in, bulk_out, int_in, int_out))
208 EXPORT_SYMBOL_GPL(usb_find_common_endpoints_reverse);
211 * usb_find_alt_setting() - Given a configuration, find the alternate setting
212 * for the given interface.
213 * @config: the configuration to search (not necessarily the current config).
214 * @iface_num: interface number to search in
215 * @alt_num: alternate interface setting number to search for.
217 * Search the configuration's interface cache for the given alt setting.
219 * Return: The alternate setting, if found. %NULL otherwise.
221 struct usb_host_interface *usb_find_alt_setting(
222 struct usb_host_config *config,
223 unsigned int iface_num,
224 unsigned int alt_num)
226 struct usb_interface_cache *intf_cache = NULL;
231 for (i = 0; i < config->desc.bNumInterfaces; i++) {
232 if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber
234 intf_cache = config->intf_cache[i];
240 for (i = 0; i < intf_cache->num_altsetting; i++)
241 if (intf_cache->altsetting[i].desc.bAlternateSetting == alt_num)
242 return &intf_cache->altsetting[i];
244 printk(KERN_DEBUG "Did not find alt setting %u for intf %u, "
245 "config %u\n", alt_num, iface_num,
246 config->desc.bConfigurationValue);
249 EXPORT_SYMBOL_GPL(usb_find_alt_setting);
252 * usb_ifnum_to_if - get the interface object with a given interface number
253 * @dev: the device whose current configuration is considered
254 * @ifnum: the desired interface
256 * This walks the device descriptor for the currently active configuration
257 * to find the interface object with the particular interface number.
259 * Note that configuration descriptors are not required to assign interface
260 * numbers sequentially, so that it would be incorrect to assume that
261 * the first interface in that descriptor corresponds to interface zero.
262 * This routine helps device drivers avoid such mistakes.
263 * However, you should make sure that you do the right thing with any
264 * alternate settings available for this interfaces.
266 * Don't call this function unless you are bound to one of the interfaces
267 * on this device or you have locked the device!
269 * Return: A pointer to the interface that has @ifnum as interface number,
270 * if found. %NULL otherwise.
272 struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
275 struct usb_host_config *config = dev->actconfig;
280 for (i = 0; i < config->desc.bNumInterfaces; i++)
281 if (config->interface[i]->altsetting[0]
282 .desc.bInterfaceNumber == ifnum)
283 return config->interface[i];
287 EXPORT_SYMBOL_GPL(usb_ifnum_to_if);
290 * usb_altnum_to_altsetting - get the altsetting structure with a given alternate setting number.
291 * @intf: the interface containing the altsetting in question
292 * @altnum: the desired alternate setting number
294 * This searches the altsetting array of the specified interface for
295 * an entry with the correct bAlternateSetting value.
297 * Note that altsettings need not be stored sequentially by number, so
298 * it would be incorrect to assume that the first altsetting entry in
299 * the array corresponds to altsetting zero. This routine helps device
300 * drivers avoid such mistakes.
302 * Don't call this function unless you are bound to the intf interface
303 * or you have locked the device!
305 * Return: A pointer to the entry of the altsetting array of @intf that
306 * has @altnum as the alternate setting number. %NULL if not found.
308 struct usb_host_interface *usb_altnum_to_altsetting(
309 const struct usb_interface *intf,
314 for (i = 0; i < intf->num_altsetting; i++) {
315 if (intf->altsetting[i].desc.bAlternateSetting == altnum)
316 return &intf->altsetting[i];
320 EXPORT_SYMBOL_GPL(usb_altnum_to_altsetting);
322 struct find_interface_arg {
324 struct device_driver *drv;
327 static int __find_interface(struct device *dev, const void *data)
329 const struct find_interface_arg *arg = data;
330 struct usb_interface *intf;
332 if (!is_usb_interface(dev))
335 if (dev->driver != arg->drv)
337 intf = to_usb_interface(dev);
338 return intf->minor == arg->minor;
342 * usb_find_interface - find usb_interface pointer for driver and device
343 * @drv: the driver whose current configuration is considered
344 * @minor: the minor number of the desired device
346 * This walks the bus device list and returns a pointer to the interface
347 * with the matching minor and driver. Note, this only works for devices
348 * that share the USB major number.
350 * Return: A pointer to the interface with the matching major and @minor.
352 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
354 struct find_interface_arg argb;
358 argb.drv = &drv->drvwrap.driver;
360 dev = bus_find_device(&usb_bus_type, NULL, &argb, __find_interface);
362 /* Drop reference count from bus_find_device */
365 return dev ? to_usb_interface(dev) : NULL;
367 EXPORT_SYMBOL_GPL(usb_find_interface);
369 struct each_dev_arg {
371 int (*fn)(struct usb_device *, void *);
374 static int __each_dev(struct device *dev, void *data)
376 struct each_dev_arg *arg = (struct each_dev_arg *)data;
378 /* There are struct usb_interface on the same bus, filter them out */
379 if (!is_usb_device(dev))
382 return arg->fn(to_usb_device(dev), arg->data);
386 * usb_for_each_dev - iterate over all USB devices in the system
387 * @data: data pointer that will be handed to the callback function
388 * @fn: callback function to be called for each USB device
390 * Iterate over all USB devices and call @fn for each, passing it @data. If it
391 * returns anything other than 0, we break the iteration prematurely and return
394 int usb_for_each_dev(void *data, int (*fn)(struct usb_device *, void *))
396 struct each_dev_arg arg = {data, fn};
398 return bus_for_each_dev(&usb_bus_type, NULL, &arg, __each_dev);
400 EXPORT_SYMBOL_GPL(usb_for_each_dev);
403 * usb_release_dev - free a usb device structure when all users of it are finished.
404 * @dev: device that's been disconnected
406 * Will be called only by the device core when all users of this usb device are
409 static void usb_release_dev(struct device *dev)
411 struct usb_device *udev;
414 udev = to_usb_device(dev);
415 hcd = bus_to_hcd(udev->bus);
417 usb_destroy_configuration(udev);
418 usb_release_bos_descriptor(udev);
419 of_node_put(dev->of_node);
421 kfree(udev->product);
422 kfree(udev->manufacturer);
427 static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
429 struct usb_device *usb_dev;
431 usb_dev = to_usb_device(dev);
433 if (add_uevent_var(env, "BUSNUM=%03d", usb_dev->bus->busnum))
436 if (add_uevent_var(env, "DEVNUM=%03d", usb_dev->devnum))
444 /* USB device Power-Management thunks.
445 * There's no need to distinguish here between quiescing a USB device
446 * and powering it down; the generic_suspend() routine takes care of
447 * it by skipping the usb_port_suspend() call for a quiesce. And for
448 * USB interfaces there's no difference at all.
451 static int usb_dev_prepare(struct device *dev)
453 return 0; /* Implement eventually? */
456 static void usb_dev_complete(struct device *dev)
458 /* Currently used only for rebinding interfaces */
459 usb_resume_complete(dev);
462 static int usb_dev_suspend(struct device *dev)
464 return usb_suspend(dev, PMSG_SUSPEND);
467 static int usb_dev_resume(struct device *dev)
469 return usb_resume(dev, PMSG_RESUME);
472 static int usb_dev_freeze(struct device *dev)
474 return usb_suspend(dev, PMSG_FREEZE);
477 static int usb_dev_thaw(struct device *dev)
479 return usb_resume(dev, PMSG_THAW);
482 static int usb_dev_poweroff(struct device *dev)
484 return usb_suspend(dev, PMSG_HIBERNATE);
487 static int usb_dev_restore(struct device *dev)
489 return usb_resume(dev, PMSG_RESTORE);
492 static const struct dev_pm_ops usb_device_pm_ops = {
493 .prepare = usb_dev_prepare,
494 .complete = usb_dev_complete,
495 .suspend = usb_dev_suspend,
496 .resume = usb_dev_resume,
497 .freeze = usb_dev_freeze,
498 .thaw = usb_dev_thaw,
499 .poweroff = usb_dev_poweroff,
500 .restore = usb_dev_restore,
501 .runtime_suspend = usb_runtime_suspend,
502 .runtime_resume = usb_runtime_resume,
503 .runtime_idle = usb_runtime_idle,
506 #endif /* CONFIG_PM */
509 static char *usb_devnode(struct device *dev,
510 umode_t *mode, kuid_t *uid, kgid_t *gid)
512 struct usb_device *usb_dev;
514 usb_dev = to_usb_device(dev);
515 return kasprintf(GFP_KERNEL, "bus/usb/%03d/%03d",
516 usb_dev->bus->busnum, usb_dev->devnum);
519 struct device_type usb_device_type = {
520 .name = "usb_device",
521 .release = usb_release_dev,
522 .uevent = usb_dev_uevent,
523 .devnode = usb_devnode,
525 .pm = &usb_device_pm_ops,
530 /* Returns 1 if @usb_bus is WUSB, 0 otherwise */
531 static unsigned usb_bus_is_wusb(struct usb_bus *bus)
533 struct usb_hcd *hcd = bus_to_hcd(bus);
534 return hcd->wireless;
537 static bool usb_dev_authorized(struct usb_device *dev, struct usb_hcd *hcd)
542 return true; /* Root hub always ok [and always wired] */
544 switch (hcd->dev_policy) {
545 case USB_DEVICE_AUTHORIZE_NONE:
549 case USB_DEVICE_AUTHORIZE_ALL:
552 case USB_DEVICE_AUTHORIZE_INTERNAL:
553 hub = usb_hub_to_struct_hub(dev->parent);
554 return hub->ports[dev->portnum - 1]->connect_type ==
555 USB_PORT_CONNECT_TYPE_HARD_WIRED;
560 * usb_alloc_dev - usb device constructor (usbcore-internal)
561 * @parent: hub to which device is connected; null to allocate a root hub
562 * @bus: bus used to access the device
563 * @port1: one-based index of port; ignored for root hubs
564 * Context: !in_interrupt()
566 * Only hub drivers (including virtual root hub drivers for host
567 * controllers) should ever call this.
569 * This call may not be used in a non-sleeping context.
571 * Return: On success, a pointer to the allocated usb device. %NULL on
574 struct usb_device *usb_alloc_dev(struct usb_device *parent,
575 struct usb_bus *bus, unsigned port1)
577 struct usb_device *dev;
578 struct usb_hcd *usb_hcd = bus_to_hcd(bus);
579 unsigned root_hub = 0;
580 unsigned raw_port = port1;
582 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
586 if (!usb_get_hcd(usb_hcd)) {
590 /* Root hubs aren't true devices, so don't allocate HCD resources */
591 if (usb_hcd->driver->alloc_dev && parent &&
592 !usb_hcd->driver->alloc_dev(usb_hcd, dev)) {
593 usb_put_hcd(bus_to_hcd(bus));
598 device_initialize(&dev->dev);
599 dev->dev.bus = &usb_bus_type;
600 dev->dev.type = &usb_device_type;
601 dev->dev.groups = usb_device_groups;
602 set_dev_node(&dev->dev, dev_to_node(bus->sysdev));
603 dev->state = USB_STATE_ATTACHED;
604 dev->lpm_disable_count = 1;
605 atomic_set(&dev->urbnum, 0);
607 INIT_LIST_HEAD(&dev->ep0.urb_list);
608 dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
609 dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
610 /* ep0 maxpacket comes later, from device descriptor */
611 usb_enable_endpoint(dev, &dev->ep0, false);
614 /* Save readable and stable topology id, distinguishing devices
615 * by location for diagnostics, tools, driver model, etc. The
616 * string is a path along hub ports, from the root. Each device's
617 * dev->devpath will be stable until USB is re-cabled, and hubs
618 * are often labeled with these port numbers. The name isn't
619 * as stable: bus->busnum changes easily from modprobe order,
620 * cardbus or pci hotplugging, and so on.
622 if (unlikely(!parent)) {
623 dev->devpath[0] = '0';
626 dev->dev.parent = bus->controller;
627 device_set_of_node_from_dev(&dev->dev, bus->sysdev);
628 dev_set_name(&dev->dev, "usb%d", bus->busnum);
631 /* match any labeling on the hubs; it's one-based */
632 if (parent->devpath[0] == '0') {
633 snprintf(dev->devpath, sizeof dev->devpath,
635 /* Root ports are not counted in route string */
638 snprintf(dev->devpath, sizeof dev->devpath,
639 "%s.%d", parent->devpath, port1);
640 /* Route string assumes hubs have less than 16 ports */
642 dev->route = parent->route +
643 (port1 << ((parent->level - 1)*4));
645 dev->route = parent->route +
646 (15 << ((parent->level - 1)*4));
649 dev->dev.parent = &parent->dev;
650 dev_set_name(&dev->dev, "%d-%s", bus->busnum, dev->devpath);
652 if (!parent->parent) {
653 /* device under root hub's port */
654 raw_port = usb_hcd_find_raw_port_number(usb_hcd,
657 dev->dev.of_node = usb_of_get_device_node(parent, raw_port);
659 /* hub driver sets up TT records */
662 dev->portnum = port1;
664 dev->parent = parent;
665 INIT_LIST_HEAD(&dev->filelist);
668 pm_runtime_set_autosuspend_delay(&dev->dev,
669 usb_autosuspend_delay * 1000);
670 dev->connect_time = jiffies;
671 dev->active_duration = -jiffies;
674 dev->authorized = usb_dev_authorized(dev, usb_hcd);
676 dev->wusb = usb_bus_is_wusb(bus) ? 1 : 0;
680 EXPORT_SYMBOL_GPL(usb_alloc_dev);
683 * usb_get_dev - increments the reference count of the usb device structure
684 * @dev: the device being referenced
686 * Each live reference to a device should be refcounted.
688 * Drivers for USB interfaces should normally record such references in
689 * their probe() methods, when they bind to an interface, and release
690 * them by calling usb_put_dev(), in their disconnect() methods.
692 * Return: A pointer to the device with the incremented reference counter.
694 struct usb_device *usb_get_dev(struct usb_device *dev)
697 get_device(&dev->dev);
700 EXPORT_SYMBOL_GPL(usb_get_dev);
703 * usb_put_dev - release a use of the usb device structure
704 * @dev: device that's been disconnected
706 * Must be called when a user of a device is finished with it. When the last
707 * user of the device calls this function, the memory of the device is freed.
709 void usb_put_dev(struct usb_device *dev)
712 put_device(&dev->dev);
714 EXPORT_SYMBOL_GPL(usb_put_dev);
717 * usb_get_intf - increments the reference count of the usb interface structure
718 * @intf: the interface being referenced
720 * Each live reference to a interface must be refcounted.
722 * Drivers for USB interfaces should normally record such references in
723 * their probe() methods, when they bind to an interface, and release
724 * them by calling usb_put_intf(), in their disconnect() methods.
726 * Return: A pointer to the interface with the incremented reference counter.
728 struct usb_interface *usb_get_intf(struct usb_interface *intf)
731 get_device(&intf->dev);
734 EXPORT_SYMBOL_GPL(usb_get_intf);
737 * usb_put_intf - release a use of the usb interface structure
738 * @intf: interface that's been decremented
740 * Must be called when a user of an interface is finished with it. When the
741 * last user of the interface calls this function, the memory of the interface
744 void usb_put_intf(struct usb_interface *intf)
747 put_device(&intf->dev);
749 EXPORT_SYMBOL_GPL(usb_put_intf);
752 * usb_intf_get_dma_device - acquire a reference on the usb interface's DMA endpoint
753 * @intf: the usb interface
755 * While a USB device cannot perform DMA operations by itself, many USB
756 * controllers can. A call to usb_intf_get_dma_device() returns the DMA endpoint
757 * for the given USB interface, if any. The returned device structure must be
758 * released with put_device().
760 * See also usb_get_dma_device().
762 * Returns: A reference to the usb interface's DMA endpoint; or NULL if none
765 struct device *usb_intf_get_dma_device(struct usb_interface *intf)
767 struct usb_device *udev = interface_to_usbdev(intf);
768 struct device *dmadev;
773 dmadev = get_device(udev->bus->sysdev);
774 if (!dmadev || !dmadev->dma_mask) {
781 EXPORT_SYMBOL_GPL(usb_intf_get_dma_device);
783 /* USB device locking
785 * USB devices and interfaces are locked using the semaphore in their
786 * embedded struct device. The hub driver guarantees that whenever a
787 * device is connected or disconnected, drivers are called with the
788 * USB device locked as well as their particular interface.
790 * Complications arise when several devices are to be locked at the same
791 * time. Only hub-aware drivers that are part of usbcore ever have to
792 * do this; nobody else needs to worry about it. The rule for locking
795 * When locking both a device and its parent, always lock the
800 * usb_lock_device_for_reset - cautiously acquire the lock for a usb device structure
801 * @udev: device that's being locked
802 * @iface: interface bound to the driver making the request (optional)
804 * Attempts to acquire the device lock, but fails if the device is
805 * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
806 * is neither BINDING nor BOUND. Rather than sleeping to wait for the
807 * lock, the routine polls repeatedly. This is to prevent deadlock with
808 * disconnect; in some drivers (such as usb-storage) the disconnect()
809 * or suspend() method will block waiting for a device reset to complete.
811 * Return: A negative error code for failure, otherwise 0.
813 int usb_lock_device_for_reset(struct usb_device *udev,
814 const struct usb_interface *iface)
816 unsigned long jiffies_expire = jiffies + HZ;
818 if (udev->state == USB_STATE_NOTATTACHED)
820 if (udev->state == USB_STATE_SUSPENDED)
821 return -EHOSTUNREACH;
822 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
823 iface->condition == USB_INTERFACE_UNBOUND))
826 while (!usb_trylock_device(udev)) {
828 /* If we can't acquire the lock after waiting one second,
829 * we're probably deadlocked */
830 if (time_after(jiffies, jiffies_expire))
834 if (udev->state == USB_STATE_NOTATTACHED)
836 if (udev->state == USB_STATE_SUSPENDED)
837 return -EHOSTUNREACH;
838 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
839 iface->condition == USB_INTERFACE_UNBOUND))
844 EXPORT_SYMBOL_GPL(usb_lock_device_for_reset);
847 * usb_get_current_frame_number - return current bus frame number
848 * @dev: the device whose bus is being queried
850 * Return: The current frame number for the USB host controller used
851 * with the given USB device. This can be used when scheduling
852 * isochronous requests.
854 * Note: Different kinds of host controller have different "scheduling
855 * horizons". While one type might support scheduling only 32 frames
856 * into the future, others could support scheduling up to 1024 frames
860 int usb_get_current_frame_number(struct usb_device *dev)
862 return usb_hcd_get_frame_number(dev);
864 EXPORT_SYMBOL_GPL(usb_get_current_frame_number);
866 /*-------------------------------------------------------------------*/
868 * __usb_get_extra_descriptor() finds a descriptor of specific type in the
869 * extra field of the interface and endpoint descriptor structs.
872 int __usb_get_extra_descriptor(char *buffer, unsigned size,
873 unsigned char type, void **ptr, size_t minsize)
875 struct usb_descriptor_header *header;
877 while (size >= sizeof(struct usb_descriptor_header)) {
878 header = (struct usb_descriptor_header *)buffer;
880 if (header->bLength < 2 || header->bLength > size) {
882 "%s: bogus descriptor, type %d length %d\n",
884 header->bDescriptorType,
889 if (header->bDescriptorType == type && header->bLength >= minsize) {
894 buffer += header->bLength;
895 size -= header->bLength;
899 EXPORT_SYMBOL_GPL(__usb_get_extra_descriptor);
902 * usb_alloc_coherent - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
903 * @dev: device the buffer will be used with
904 * @size: requested buffer size
905 * @mem_flags: affect whether allocation may block
906 * @dma: used to return DMA address of buffer
908 * Return: Either null (indicating no buffer could be allocated), or the
909 * cpu-space pointer to a buffer that may be used to perform DMA to the
910 * specified device. Such cpu-space buffers are returned along with the DMA
911 * address (through the pointer provided).
914 * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
915 * to avoid behaviors like using "DMA bounce buffers", or thrashing IOMMU
916 * hardware during URB completion/resubmit. The implementation varies between
917 * platforms, depending on details of how DMA will work to this device.
918 * Using these buffers also eliminates cacheline sharing problems on
919 * architectures where CPU caches are not DMA-coherent. On systems without
920 * bus-snooping caches, these buffers are uncached.
922 * When the buffer is no longer used, free it with usb_free_coherent().
924 void *usb_alloc_coherent(struct usb_device *dev, size_t size, gfp_t mem_flags,
927 if (!dev || !dev->bus)
929 return hcd_buffer_alloc(dev->bus, size, mem_flags, dma);
931 EXPORT_SYMBOL_GPL(usb_alloc_coherent);
934 * usb_free_coherent - free memory allocated with usb_alloc_coherent()
935 * @dev: device the buffer was used with
936 * @size: requested buffer size
937 * @addr: CPU address of buffer
938 * @dma: DMA address of buffer
940 * This reclaims an I/O buffer, letting it be reused. The memory must have
941 * been allocated using usb_alloc_coherent(), and the parameters must match
942 * those provided in that allocation request.
944 void usb_free_coherent(struct usb_device *dev, size_t size, void *addr,
947 if (!dev || !dev->bus)
951 hcd_buffer_free(dev->bus, size, addr, dma);
953 EXPORT_SYMBOL_GPL(usb_free_coherent);
956 * Notifications of device and interface registration
958 static int usb_bus_notify(struct notifier_block *nb, unsigned long action,
961 struct device *dev = data;
964 case BUS_NOTIFY_ADD_DEVICE:
965 if (dev->type == &usb_device_type)
966 (void) usb_create_sysfs_dev_files(to_usb_device(dev));
967 else if (dev->type == &usb_if_device_type)
968 usb_create_sysfs_intf_files(to_usb_interface(dev));
971 case BUS_NOTIFY_DEL_DEVICE:
972 if (dev->type == &usb_device_type)
973 usb_remove_sysfs_dev_files(to_usb_device(dev));
974 else if (dev->type == &usb_if_device_type)
975 usb_remove_sysfs_intf_files(to_usb_interface(dev));
981 static struct notifier_block usb_bus_nb = {
982 .notifier_call = usb_bus_notify,
985 static struct dentry *usb_devices_root;
987 static void usb_debugfs_init(void)
989 usb_devices_root = debugfs_create_file("devices", 0444, usb_debug_root,
990 NULL, &usbfs_devices_fops);
993 static void usb_debugfs_cleanup(void)
995 debugfs_remove(usb_devices_root);
1001 static int __init usb_init(void)
1004 if (usb_disabled()) {
1005 pr_info("%s: USB support disabled\n", usbcore_name);
1008 usb_init_pool_max();
1012 usb_acpi_register();
1013 retval = bus_register(&usb_bus_type);
1015 goto bus_register_failed;
1016 retval = bus_register_notifier(&usb_bus_type, &usb_bus_nb);
1018 goto bus_notifier_failed;
1019 retval = usb_major_init();
1021 goto major_init_failed;
1022 retval = usb_register(&usbfs_driver);
1024 goto driver_register_failed;
1025 retval = usb_devio_init();
1027 goto usb_devio_init_failed;
1028 retval = usb_hub_init();
1030 goto hub_init_failed;
1031 retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
1037 usb_devio_cleanup();
1038 usb_devio_init_failed:
1039 usb_deregister(&usbfs_driver);
1040 driver_register_failed:
1041 usb_major_cleanup();
1043 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1044 bus_notifier_failed:
1045 bus_unregister(&usb_bus_type);
1046 bus_register_failed:
1047 usb_acpi_unregister();
1048 usb_debugfs_cleanup();
1056 static void __exit usb_exit(void)
1058 /* This will matter if shutdown/reboot does exitcalls. */
1062 usb_release_quirk_list();
1063 usb_deregister_device_driver(&usb_generic_driver);
1064 usb_major_cleanup();
1065 usb_deregister(&usbfs_driver);
1066 usb_devio_cleanup();
1068 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1069 bus_unregister(&usb_bus_type);
1070 usb_acpi_unregister();
1071 usb_debugfs_cleanup();
1072 idr_destroy(&usb_bus_idr);
1075 subsys_initcall(usb_init);
1076 module_exit(usb_exit);
1077 MODULE_LICENSE("GPL");