2 * drivers/usb/core/usb.c
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
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..
19 * Think of this as a "USB library" rather than anything else.
20 * It should be considered a slave, with no callbacks. Callbacks
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/smp_lock.h>
35 #include <linux/usb.h>
36 #include <linux/mutex.h>
37 #include <linux/workqueue.h>
40 #include <asm/scatterlist.h>
42 #include <linux/dma-mapping.h>
48 const char *usbcore_name = "usbcore";
50 static int nousb; /* Disable USB when built into kernel image */
52 /* Workqueue for autosuspend and for remote wakeup of root hubs */
53 struct workqueue_struct *ksuspend_usb_wq;
55 #ifdef CONFIG_USB_SUSPEND
56 static int usb_autosuspend_delay = 2; /* Default delay value,
58 module_param_named(autosuspend, usb_autosuspend_delay, uint, 0644);
59 MODULE_PARM_DESC(autosuspend, "default autosuspend delay");
62 #define usb_autosuspend_delay 0
67 * usb_ifnum_to_if - get the interface object with a given interface number
68 * @dev: the device whose current configuration is considered
69 * @ifnum: the desired interface
71 * This walks the device descriptor for the currently active configuration
72 * and returns a pointer to the interface with that particular interface
75 * Note that configuration descriptors are not required to assign interface
76 * numbers sequentially, so that it would be incorrect to assume that
77 * the first interface in that descriptor corresponds to interface zero.
78 * This routine helps device drivers avoid such mistakes.
79 * However, you should make sure that you do the right thing with any
80 * alternate settings available for this interfaces.
82 * Don't call this function unless you are bound to one of the interfaces
83 * on this device or you have locked the device!
85 struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
88 struct usb_host_config *config = dev->actconfig;
93 for (i = 0; i < config->desc.bNumInterfaces; i++)
94 if (config->interface[i]->altsetting[0]
95 .desc.bInterfaceNumber == ifnum)
96 return config->interface[i];
102 * usb_altnum_to_altsetting - get the altsetting structure with a given
103 * alternate setting number.
104 * @intf: the interface containing the altsetting in question
105 * @altnum: the desired alternate setting number
107 * This searches the altsetting array of the specified interface for
108 * an entry with the correct bAlternateSetting value and returns a pointer
109 * to that entry, or null.
111 * Note that altsettings need not be stored sequentially by number, so
112 * it would be incorrect to assume that the first altsetting entry in
113 * the array corresponds to altsetting zero. This routine helps device
114 * drivers avoid such mistakes.
116 * Don't call this function unless you are bound to the intf interface
117 * or you have locked the device!
119 struct usb_host_interface *usb_altnum_to_altsetting(const struct usb_interface *intf,
124 for (i = 0; i < intf->num_altsetting; i++) {
125 if (intf->altsetting[i].desc.bAlternateSetting == altnum)
126 return &intf->altsetting[i];
131 struct find_interface_arg {
133 struct usb_interface *interface;
136 static int __find_interface(struct device * dev, void * data)
138 struct find_interface_arg *arg = data;
139 struct usb_interface *intf;
141 /* can't look at usb devices, only interfaces */
142 if (is_usb_device(dev))
145 intf = to_usb_interface(dev);
146 if (intf->minor != -1 && intf->minor == arg->minor) {
147 arg->interface = intf;
154 * usb_find_interface - find usb_interface pointer for driver and device
155 * @drv: the driver whose current configuration is considered
156 * @minor: the minor number of the desired device
158 * This walks the driver device list and returns a pointer to the interface
159 * with the matching minor. Note, this only works for devices that share the
162 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
164 struct find_interface_arg argb;
168 argb.interface = NULL;
169 /* eat the error, it will be in argb.interface */
170 retval = driver_for_each_device(&drv->drvwrap.driver, NULL, &argb,
172 return argb.interface;
176 * usb_release_dev - free a usb device structure when all users of it are finished.
177 * @dev: device that's been disconnected
179 * Will be called only by the device core when all users of this usb device are
182 static void usb_release_dev(struct device *dev)
184 struct usb_device *udev;
186 udev = to_usb_device(dev);
188 #ifdef CONFIG_USB_SUSPEND
189 cancel_delayed_work(&udev->autosuspend);
190 flush_workqueue(ksuspend_usb_wq);
192 usb_destroy_configuration(udev);
193 usb_put_hcd(bus_to_hcd(udev->bus));
194 kfree(udev->product);
195 kfree(udev->manufacturer);
202 static int ksuspend_usb_init(void)
204 ksuspend_usb_wq = create_singlethread_workqueue("ksuspend_usbd");
205 if (!ksuspend_usb_wq)
210 static void ksuspend_usb_cleanup(void)
212 destroy_workqueue(ksuspend_usb_wq);
217 #define ksuspend_usb_init() 0
218 #define ksuspend_usb_cleanup() do {} while (0)
220 #endif /* CONFIG_PM */
223 * usb_alloc_dev - usb device constructor (usbcore-internal)
224 * @parent: hub to which device is connected; null to allocate a root hub
225 * @bus: bus used to access the device
226 * @port1: one-based index of port; ignored for root hubs
227 * Context: !in_interrupt()
229 * Only hub drivers (including virtual root hub drivers for host
230 * controllers) should ever call this.
232 * This call may not be used in a non-sleeping context.
235 usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port1)
237 struct usb_device *dev;
239 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
243 if (!usb_get_hcd(bus_to_hcd(bus))) {
248 device_initialize(&dev->dev);
249 dev->dev.bus = &usb_bus_type;
250 dev->dev.dma_mask = bus->controller->dma_mask;
251 dev->dev.release = usb_release_dev;
252 dev->state = USB_STATE_ATTACHED;
254 /* This magic assignment distinguishes devices from interfaces */
255 dev->dev.platform_data = &usb_generic_driver;
257 INIT_LIST_HEAD(&dev->ep0.urb_list);
258 dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
259 dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
260 /* ep0 maxpacket comes later, from device descriptor */
261 dev->ep_in[0] = dev->ep_out[0] = &dev->ep0;
263 /* Save readable and stable topology id, distinguishing devices
264 * by location for diagnostics, tools, driver model, etc. The
265 * string is a path along hub ports, from the root. Each device's
266 * dev->devpath will be stable until USB is re-cabled, and hubs
267 * are often labeled with these port numbers. The bus_id isn't
268 * as stable: bus->busnum changes easily from modprobe order,
269 * cardbus or pci hotplugging, and so on.
271 if (unlikely(!parent)) {
272 dev->devpath[0] = '0';
274 dev->dev.parent = bus->controller;
275 sprintf(&dev->dev.bus_id[0], "usb%d", bus->busnum);
277 /* match any labeling on the hubs; it's one-based */
278 if (parent->devpath[0] == '0')
279 snprintf(dev->devpath, sizeof dev->devpath,
282 snprintf(dev->devpath, sizeof dev->devpath,
283 "%s.%d", parent->devpath, port1);
285 dev->dev.parent = &parent->dev;
286 sprintf(&dev->dev.bus_id[0], "%d-%s",
287 bus->busnum, dev->devpath);
289 /* hub driver sets up TT records */
292 dev->portnum = port1;
294 dev->parent = parent;
295 INIT_LIST_HEAD(&dev->filelist);
298 mutex_init(&dev->pm_mutex);
299 INIT_DELAYED_WORK(&dev->autosuspend, usb_autosuspend_work);
300 dev->autosuspend_delay = usb_autosuspend_delay * HZ;
306 * usb_get_dev - increments the reference count of the usb device structure
307 * @dev: the device being referenced
309 * Each live reference to a device should be refcounted.
311 * Drivers for USB interfaces should normally record such references in
312 * their probe() methods, when they bind to an interface, and release
313 * them by calling usb_put_dev(), in their disconnect() methods.
315 * A pointer to the device with the incremented reference counter is returned.
317 struct usb_device *usb_get_dev(struct usb_device *dev)
320 get_device(&dev->dev);
325 * usb_put_dev - release a use of the usb device structure
326 * @dev: device that's been disconnected
328 * Must be called when a user of a device is finished with it. When the last
329 * user of the device calls this function, the memory of the device is freed.
331 void usb_put_dev(struct usb_device *dev)
334 put_device(&dev->dev);
338 * usb_get_intf - increments the reference count of the usb interface structure
339 * @intf: the interface being referenced
341 * Each live reference to a interface must be refcounted.
343 * Drivers for USB interfaces should normally record such references in
344 * their probe() methods, when they bind to an interface, and release
345 * them by calling usb_put_intf(), in their disconnect() methods.
347 * A pointer to the interface with the incremented reference counter is
350 struct usb_interface *usb_get_intf(struct usb_interface *intf)
353 get_device(&intf->dev);
358 * usb_put_intf - release a use of the usb interface structure
359 * @intf: interface that's been decremented
361 * Must be called when a user of an interface is finished with it. When the
362 * last user of the interface calls this function, the memory of the interface
365 void usb_put_intf(struct usb_interface *intf)
368 put_device(&intf->dev);
372 /* USB device locking
374 * USB devices and interfaces are locked using the semaphore in their
375 * embedded struct device. The hub driver guarantees that whenever a
376 * device is connected or disconnected, drivers are called with the
377 * USB device locked as well as their particular interface.
379 * Complications arise when several devices are to be locked at the same
380 * time. Only hub-aware drivers that are part of usbcore ever have to
381 * do this; nobody else needs to worry about it. The rule for locking
384 * When locking both a device and its parent, always lock the
389 * usb_lock_device_for_reset - cautiously acquire the lock for a
390 * usb device structure
391 * @udev: device that's being locked
392 * @iface: interface bound to the driver making the request (optional)
394 * Attempts to acquire the device lock, but fails if the device is
395 * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
396 * is neither BINDING nor BOUND. Rather than sleeping to wait for the
397 * lock, the routine polls repeatedly. This is to prevent deadlock with
398 * disconnect; in some drivers (such as usb-storage) the disconnect()
399 * or suspend() method will block waiting for a device reset to complete.
401 * Returns a negative error code for failure, otherwise 1 or 0 to indicate
402 * that the device will or will not have to be unlocked. (0 can be
403 * returned when an interface is given and is BINDING, because in that
404 * case the driver already owns the device lock.)
406 int usb_lock_device_for_reset(struct usb_device *udev,
407 const struct usb_interface *iface)
409 unsigned long jiffies_expire = jiffies + HZ;
411 if (udev->state == USB_STATE_NOTATTACHED)
413 if (udev->state == USB_STATE_SUSPENDED)
414 return -EHOSTUNREACH;
416 switch (iface->condition) {
417 case USB_INTERFACE_BINDING:
419 case USB_INTERFACE_BOUND:
426 while (usb_trylock_device(udev) != 0) {
428 /* If we can't acquire the lock after waiting one second,
429 * we're probably deadlocked */
430 if (time_after(jiffies, jiffies_expire))
434 if (udev->state == USB_STATE_NOTATTACHED)
436 if (udev->state == USB_STATE_SUSPENDED)
437 return -EHOSTUNREACH;
438 if (iface && iface->condition != USB_INTERFACE_BOUND)
445 static struct usb_device *match_device(struct usb_device *dev,
446 u16 vendor_id, u16 product_id)
448 struct usb_device *ret_dev = NULL;
451 dev_dbg(&dev->dev, "check for vendor %04x, product %04x ...\n",
452 le16_to_cpu(dev->descriptor.idVendor),
453 le16_to_cpu(dev->descriptor.idProduct));
455 /* see if this device matches */
456 if ((vendor_id == le16_to_cpu(dev->descriptor.idVendor)) &&
457 (product_id == le16_to_cpu(dev->descriptor.idProduct))) {
458 dev_dbg(&dev->dev, "matched this device!\n");
459 ret_dev = usb_get_dev(dev);
463 /* look through all of the children of this device */
464 for (child = 0; child < dev->maxchild; ++child) {
465 if (dev->children[child]) {
466 usb_lock_device(dev->children[child]);
467 ret_dev = match_device(dev->children[child],
468 vendor_id, product_id);
469 usb_unlock_device(dev->children[child]);
479 * usb_find_device - find a specific usb device in the system
480 * @vendor_id: the vendor id of the device to find
481 * @product_id: the product id of the device to find
483 * Returns a pointer to a struct usb_device if such a specified usb
484 * device is present in the system currently. The usage count of the
485 * device will be incremented if a device is found. Make sure to call
486 * usb_put_dev() when the caller is finished with the device.
488 * If a device with the specified vendor and product id is not found,
491 struct usb_device *usb_find_device(u16 vendor_id, u16 product_id)
493 struct list_head *buslist;
495 struct usb_device *dev = NULL;
497 mutex_lock(&usb_bus_list_lock);
498 for (buslist = usb_bus_list.next;
499 buslist != &usb_bus_list;
500 buslist = buslist->next) {
501 bus = container_of(buslist, struct usb_bus, bus_list);
504 usb_lock_device(bus->root_hub);
505 dev = match_device(bus->root_hub, vendor_id, product_id);
506 usb_unlock_device(bus->root_hub);
511 mutex_unlock(&usb_bus_list_lock);
516 * usb_get_current_frame_number - return current bus frame number
517 * @dev: the device whose bus is being queried
519 * Returns the current frame number for the USB host controller
520 * used with the given USB device. This can be used when scheduling
521 * isochronous requests.
523 * Note that different kinds of host controller have different
524 * "scheduling horizons". While one type might support scheduling only
525 * 32 frames into the future, others could support scheduling up to
526 * 1024 frames into the future.
528 int usb_get_current_frame_number(struct usb_device *dev)
530 return usb_hcd_get_frame_number(dev);
533 /*-------------------------------------------------------------------*/
535 * __usb_get_extra_descriptor() finds a descriptor of specific type in the
536 * extra field of the interface and endpoint descriptor structs.
539 int __usb_get_extra_descriptor(char *buffer, unsigned size,
540 unsigned char type, void **ptr)
542 struct usb_descriptor_header *header;
544 while (size >= sizeof(struct usb_descriptor_header)) {
545 header = (struct usb_descriptor_header *)buffer;
547 if (header->bLength < 2) {
549 "%s: bogus descriptor, type %d length %d\n",
551 header->bDescriptorType,
556 if (header->bDescriptorType == type) {
561 buffer += header->bLength;
562 size -= header->bLength;
568 * usb_buffer_alloc - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
569 * @dev: device the buffer will be used with
570 * @size: requested buffer size
571 * @mem_flags: affect whether allocation may block
572 * @dma: used to return DMA address of buffer
574 * Return value is either null (indicating no buffer could be allocated), or
575 * the cpu-space pointer to a buffer that may be used to perform DMA to the
576 * specified device. Such cpu-space buffers are returned along with the DMA
577 * address (through the pointer provided).
579 * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
580 * to avoid behaviors like using "DMA bounce buffers", or tying down I/O
581 * mapping hardware for long idle periods. The implementation varies between
582 * platforms, depending on details of how DMA will work to this device.
583 * Using these buffers also helps prevent cacheline sharing problems on
584 * architectures where CPU caches are not DMA-coherent.
586 * When the buffer is no longer used, free it with usb_buffer_free().
588 void *usb_buffer_alloc(
589 struct usb_device *dev,
595 if (!dev || !dev->bus)
597 return hcd_buffer_alloc(dev->bus, size, mem_flags, dma);
601 * usb_buffer_free - free memory allocated with usb_buffer_alloc()
602 * @dev: device the buffer was used with
603 * @size: requested buffer size
604 * @addr: CPU address of buffer
605 * @dma: DMA address of buffer
607 * This reclaims an I/O buffer, letting it be reused. The memory must have
608 * been allocated using usb_buffer_alloc(), and the parameters must match
609 * those provided in that allocation request.
611 void usb_buffer_free(
612 struct usb_device *dev,
618 if (!dev || !dev->bus)
622 hcd_buffer_free(dev->bus, size, addr, dma);
626 * usb_buffer_map - create DMA mapping(s) for an urb
627 * @urb: urb whose transfer_buffer/setup_packet will be mapped
629 * Return value is either null (indicating no buffer could be mapped), or
630 * the parameter. URB_NO_TRANSFER_DMA_MAP and URB_NO_SETUP_DMA_MAP are
631 * added to urb->transfer_flags if the operation succeeds. If the device
632 * is connected to this system through a non-DMA controller, this operation
635 * This call would normally be used for an urb which is reused, perhaps
636 * as the target of a large periodic transfer, with usb_buffer_dmasync()
637 * calls to synchronize memory and dma state.
639 * Reverse the effect of this call with usb_buffer_unmap().
642 struct urb *usb_buffer_map(struct urb *urb)
645 struct device *controller;
649 || !(bus = urb->dev->bus)
650 || !(controller = bus->controller))
653 if (controller->dma_mask) {
654 urb->transfer_dma = dma_map_single(controller,
655 urb->transfer_buffer, urb->transfer_buffer_length,
656 usb_pipein(urb->pipe)
657 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
658 if (usb_pipecontrol(urb->pipe))
659 urb->setup_dma = dma_map_single(controller,
661 sizeof(struct usb_ctrlrequest),
663 // FIXME generic api broken like pci, can't report errors
664 // if (urb->transfer_dma == DMA_ADDR_INVALID) return 0;
666 urb->transfer_dma = ~0;
667 urb->transfer_flags |= (URB_NO_TRANSFER_DMA_MAP
668 | URB_NO_SETUP_DMA_MAP);
673 /* XXX DISABLED, no users currently. If you wish to re-enable this
674 * XXX please determine whether the sync is to transfer ownership of
675 * XXX the buffer from device to cpu or vice verse, and thusly use the
676 * XXX appropriate _for_{cpu,device}() method. -DaveM
681 * usb_buffer_dmasync - synchronize DMA and CPU view of buffer(s)
682 * @urb: urb whose transfer_buffer/setup_packet will be synchronized
684 void usb_buffer_dmasync(struct urb *urb)
687 struct device *controller;
690 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
692 || !(bus = urb->dev->bus)
693 || !(controller = bus->controller))
696 if (controller->dma_mask) {
697 dma_sync_single(controller,
698 urb->transfer_dma, urb->transfer_buffer_length,
699 usb_pipein(urb->pipe)
700 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
701 if (usb_pipecontrol(urb->pipe))
702 dma_sync_single(controller,
704 sizeof(struct usb_ctrlrequest),
711 * usb_buffer_unmap - free DMA mapping(s) for an urb
712 * @urb: urb whose transfer_buffer will be unmapped
714 * Reverses the effect of usb_buffer_map().
717 void usb_buffer_unmap(struct urb *urb)
720 struct device *controller;
723 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
725 || !(bus = urb->dev->bus)
726 || !(controller = bus->controller))
729 if (controller->dma_mask) {
730 dma_unmap_single(controller,
731 urb->transfer_dma, urb->transfer_buffer_length,
732 usb_pipein(urb->pipe)
733 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
734 if (usb_pipecontrol(urb->pipe))
735 dma_unmap_single(controller,
737 sizeof(struct usb_ctrlrequest),
740 urb->transfer_flags &= ~(URB_NO_TRANSFER_DMA_MAP
741 | URB_NO_SETUP_DMA_MAP);
746 * usb_buffer_map_sg - create scatterlist DMA mapping(s) for an endpoint
747 * @dev: device to which the scatterlist will be mapped
748 * @pipe: endpoint defining the mapping direction
749 * @sg: the scatterlist to map
750 * @nents: the number of entries in the scatterlist
752 * Return value is either < 0 (indicating no buffers could be mapped), or
753 * the number of DMA mapping array entries in the scatterlist.
755 * The caller is responsible for placing the resulting DMA addresses from
756 * the scatterlist into URB transfer buffer pointers, and for setting the
757 * URB_NO_TRANSFER_DMA_MAP transfer flag in each of those URBs.
759 * Top I/O rates come from queuing URBs, instead of waiting for each one
760 * to complete before starting the next I/O. This is particularly easy
761 * to do with scatterlists. Just allocate and submit one URB for each DMA
762 * mapping entry returned, stopping on the first error or when all succeed.
763 * Better yet, use the usb_sg_*() calls, which do that (and more) for you.
765 * This call would normally be used when translating scatterlist requests,
766 * rather than usb_buffer_map(), since on some hardware (with IOMMUs) it
767 * may be able to coalesce mappings for improved I/O efficiency.
769 * Reverse the effect of this call with usb_buffer_unmap_sg().
771 int usb_buffer_map_sg(const struct usb_device *dev, unsigned pipe,
772 struct scatterlist *sg, int nents)
775 struct device *controller;
778 || usb_pipecontrol(pipe)
780 || !(controller = bus->controller)
781 || !controller->dma_mask)
784 // FIXME generic api broken like pci, can't report errors
785 return dma_map_sg(controller, sg, nents,
786 usb_pipein(pipe) ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
789 /* XXX DISABLED, no users currently. If you wish to re-enable this
790 * XXX please determine whether the sync is to transfer ownership of
791 * XXX the buffer from device to cpu or vice verse, and thusly use the
792 * XXX appropriate _for_{cpu,device}() method. -DaveM
797 * usb_buffer_dmasync_sg - synchronize DMA and CPU view of scatterlist buffer(s)
798 * @dev: device to which the scatterlist will be mapped
799 * @pipe: endpoint defining the mapping direction
800 * @sg: the scatterlist to synchronize
801 * @n_hw_ents: the positive return value from usb_buffer_map_sg
803 * Use this when you are re-using a scatterlist's data buffers for
804 * another USB request.
806 void usb_buffer_dmasync_sg(const struct usb_device *dev, unsigned pipe,
807 struct scatterlist *sg, int n_hw_ents)
810 struct device *controller;
814 || !(controller = bus->controller)
815 || !controller->dma_mask)
818 dma_sync_sg(controller, sg, n_hw_ents,
819 usb_pipein(pipe) ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
824 * usb_buffer_unmap_sg - free DMA mapping(s) for a scatterlist
825 * @dev: device to which the scatterlist will be mapped
826 * @pipe: endpoint defining the mapping direction
827 * @sg: the scatterlist to unmap
828 * @n_hw_ents: the positive return value from usb_buffer_map_sg
830 * Reverses the effect of usb_buffer_map_sg().
832 void usb_buffer_unmap_sg(const struct usb_device *dev, unsigned pipe,
833 struct scatterlist *sg, int n_hw_ents)
836 struct device *controller;
840 || !(controller = bus->controller)
841 || !controller->dma_mask)
844 dma_unmap_sg(controller, sg, n_hw_ents,
845 usb_pipein(pipe) ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
848 /* format to disable USB on kernel command line is: nousb */
849 __module_param_call("", nousb, param_set_bool, param_get_bool, &nousb, 0444);
852 * for external read access to <nousb>
854 int usb_disabled(void)
862 static int __init usb_init(void)
866 pr_info("%s: USB support disabled\n", usbcore_name);
870 retval = ksuspend_usb_init();
873 retval = bus_register(&usb_bus_type);
875 goto bus_register_failed;
876 retval = usb_host_init();
878 goto host_init_failed;
879 retval = usb_major_init();
881 goto major_init_failed;
882 retval = usb_register(&usbfs_driver);
884 goto driver_register_failed;
885 retval = usbdev_init();
887 goto usbdevice_init_failed;
888 retval = usbfs_init();
891 retval = usb_hub_init();
893 goto hub_init_failed;
894 retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
903 usbdevice_init_failed:
904 usb_deregister(&usbfs_driver);
905 driver_register_failed:
910 bus_unregister(&usb_bus_type);
912 ksuspend_usb_cleanup();
920 static void __exit usb_exit(void)
922 /* This will matter if shutdown/reboot does exitcalls. */
926 usb_deregister_device_driver(&usb_generic_driver);
929 usb_deregister(&usbfs_driver);
933 bus_unregister(&usb_bus_type);
934 ksuspend_usb_cleanup();
937 subsys_initcall(usb_init);
938 module_exit(usb_exit);
941 * USB may be built into the kernel or be built as modules.
942 * These symbols are exported for device (or host controller)
943 * driver modules to use.
946 EXPORT_SYMBOL(usb_disabled);
948 EXPORT_SYMBOL_GPL(usb_get_intf);
949 EXPORT_SYMBOL_GPL(usb_put_intf);
951 EXPORT_SYMBOL(usb_put_dev);
952 EXPORT_SYMBOL(usb_get_dev);
953 EXPORT_SYMBOL(usb_hub_tt_clear_buffer);
955 EXPORT_SYMBOL(usb_lock_device_for_reset);
957 EXPORT_SYMBOL(usb_find_interface);
958 EXPORT_SYMBOL(usb_ifnum_to_if);
959 EXPORT_SYMBOL(usb_altnum_to_altsetting);
961 EXPORT_SYMBOL(__usb_get_extra_descriptor);
963 EXPORT_SYMBOL(usb_find_device);
964 EXPORT_SYMBOL(usb_get_current_frame_number);
966 EXPORT_SYMBOL(usb_buffer_alloc);
967 EXPORT_SYMBOL(usb_buffer_free);
970 EXPORT_SYMBOL(usb_buffer_map);
971 EXPORT_SYMBOL(usb_buffer_dmasync);
972 EXPORT_SYMBOL(usb_buffer_unmap);
975 EXPORT_SYMBOL(usb_buffer_map_sg);
977 EXPORT_SYMBOL(usb_buffer_dmasync_sg);
979 EXPORT_SYMBOL(usb_buffer_unmap_sg);
981 MODULE_LICENSE("GPL");