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/usb.h>
35 #include <linux/mutex.h>
36 #include <linux/workqueue.h>
39 #include <linux/scatterlist.h>
41 #include <linux/dma-mapping.h>
47 const char *usbcore_name = "usbcore";
49 static int nousb; /* Disable USB when built into kernel image */
51 /* Workqueue for autosuspend and for remote wakeup of root hubs */
52 struct workqueue_struct *ksuspend_usb_wq;
54 #ifdef CONFIG_USB_SUSPEND
55 static int usb_autosuspend_delay = 2; /* Default delay value,
57 module_param_named(autosuspend, usb_autosuspend_delay, int, 0644);
58 MODULE_PARM_DESC(autosuspend, "default autosuspend delay");
61 #define usb_autosuspend_delay 0
66 * usb_ifnum_to_if - get the interface object with a given interface number
67 * @dev: the device whose current configuration is considered
68 * @ifnum: the desired interface
70 * This walks the device descriptor for the currently active configuration
71 * and returns a pointer to the interface with that particular interface
74 * Note that configuration descriptors are not required to assign interface
75 * numbers sequentially, so that it would be incorrect to assume that
76 * the first interface in that descriptor corresponds to interface zero.
77 * This routine helps device drivers avoid such mistakes.
78 * However, you should make sure that you do the right thing with any
79 * alternate settings available for this interfaces.
81 * Don't call this function unless you are bound to one of the interfaces
82 * on this device or you have locked the device!
84 struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
87 struct usb_host_config *config = dev->actconfig;
92 for (i = 0; i < config->desc.bNumInterfaces; i++)
93 if (config->interface[i]->altsetting[0]
94 .desc.bInterfaceNumber == ifnum)
95 return config->interface[i];
101 * usb_altnum_to_altsetting - get the altsetting structure with a given
102 * alternate setting number.
103 * @intf: the interface containing the altsetting in question
104 * @altnum: the desired alternate setting number
106 * This searches the altsetting array of the specified interface for
107 * an entry with the correct bAlternateSetting value and returns a pointer
108 * to that entry, or null.
110 * Note that altsettings need not be stored sequentially by number, so
111 * it would be incorrect to assume that the first altsetting entry in
112 * the array corresponds to altsetting zero. This routine helps device
113 * drivers avoid such mistakes.
115 * Don't call this function unless you are bound to the intf interface
116 * or you have locked the device!
118 struct usb_host_interface *usb_altnum_to_altsetting(const struct usb_interface *intf,
123 for (i = 0; i < intf->num_altsetting; i++) {
124 if (intf->altsetting[i].desc.bAlternateSetting == altnum)
125 return &intf->altsetting[i];
130 struct find_interface_arg {
132 struct usb_interface *interface;
135 static int __find_interface(struct device * dev, void * data)
137 struct find_interface_arg *arg = data;
138 struct usb_interface *intf;
140 /* can't look at usb devices, only interfaces */
141 if (is_usb_device(dev))
144 intf = to_usb_interface(dev);
145 if (intf->minor != -1 && intf->minor == arg->minor) {
146 arg->interface = intf;
153 * usb_find_interface - find usb_interface pointer for driver and device
154 * @drv: the driver whose current configuration is considered
155 * @minor: the minor number of the desired device
157 * This walks the driver device list and returns a pointer to the interface
158 * with the matching minor. Note, this only works for devices that share the
161 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
163 struct find_interface_arg argb;
167 argb.interface = NULL;
168 /* eat the error, it will be in argb.interface */
169 retval = driver_for_each_device(&drv->drvwrap.driver, NULL, &argb,
171 return argb.interface;
175 * usb_release_dev - free a usb device structure when all users of it are finished.
176 * @dev: device that's been disconnected
178 * Will be called only by the device core when all users of this usb device are
181 static void usb_release_dev(struct device *dev)
183 struct usb_device *udev;
185 udev = to_usb_device(dev);
187 usb_destroy_configuration(udev);
188 usb_put_hcd(bus_to_hcd(udev->bus));
189 kfree(udev->product);
190 kfree(udev->manufacturer);
195 #ifdef CONFIG_HOTPLUG
196 static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
198 struct usb_device *usb_dev;
200 usb_dev = to_usb_device(dev);
202 if (add_uevent_var(env, "BUSNUM=%03d", usb_dev->bus->busnum))
205 if (add_uevent_var(env, "DEVNUM=%03d", usb_dev->devnum))
213 static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
217 #endif /* CONFIG_HOTPLUG */
219 struct device_type usb_device_type = {
220 .name = "usb_device",
221 .release = usb_release_dev,
222 .uevent = usb_dev_uevent,
227 static int ksuspend_usb_init(void)
229 /* This workqueue is supposed to be both freezable and
230 * singlethreaded. Its job doesn't justify running on more
233 ksuspend_usb_wq = create_singlethread_workqueue("ksuspend_usbd");
234 if (!ksuspend_usb_wq)
239 static void ksuspend_usb_cleanup(void)
241 destroy_workqueue(ksuspend_usb_wq);
246 #define ksuspend_usb_init() 0
247 #define ksuspend_usb_cleanup() do {} while (0)
249 #endif /* CONFIG_PM */
252 /* Returns 1 if @usb_bus is WUSB, 0 otherwise */
253 static unsigned usb_bus_is_wusb(struct usb_bus *bus)
255 struct usb_hcd *hcd = container_of(bus, struct usb_hcd, self);
256 return hcd->wireless;
261 * usb_alloc_dev - usb device constructor (usbcore-internal)
262 * @parent: hub to which device is connected; null to allocate a root hub
263 * @bus: bus used to access the device
264 * @port1: one-based index of port; ignored for root hubs
265 * Context: !in_interrupt()
267 * Only hub drivers (including virtual root hub drivers for host
268 * controllers) should ever call this.
270 * This call may not be used in a non-sleeping context.
273 usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port1)
275 struct usb_device *dev;
276 struct usb_hcd *usb_hcd = container_of(bus, struct usb_hcd, self);
277 unsigned root_hub = 0;
279 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
283 if (!usb_get_hcd(bus_to_hcd(bus))) {
288 device_initialize(&dev->dev);
289 dev->dev.bus = &usb_bus_type;
290 dev->dev.type = &usb_device_type;
291 dev->dev.dma_mask = bus->controller->dma_mask;
292 set_dev_node(&dev->dev, dev_to_node(bus->controller));
293 dev->state = USB_STATE_ATTACHED;
294 atomic_set(&dev->urbnum, 0);
296 INIT_LIST_HEAD(&dev->ep0.urb_list);
297 dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
298 dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
299 /* ep0 maxpacket comes later, from device descriptor */
300 usb_enable_endpoint(dev, &dev->ep0);
303 /* Save readable and stable topology id, distinguishing devices
304 * by location for diagnostics, tools, driver model, etc. The
305 * string is a path along hub ports, from the root. Each device's
306 * dev->devpath will be stable until USB is re-cabled, and hubs
307 * are often labeled with these port numbers. The bus_id isn't
308 * as stable: bus->busnum changes easily from modprobe order,
309 * cardbus or pci hotplugging, and so on.
311 if (unlikely(!parent)) {
312 dev->devpath[0] = '0';
314 dev->dev.parent = bus->controller;
315 sprintf(&dev->dev.bus_id[0], "usb%d", bus->busnum);
318 /* match any labeling on the hubs; it's one-based */
319 if (parent->devpath[0] == '0')
320 snprintf(dev->devpath, sizeof dev->devpath,
323 snprintf(dev->devpath, sizeof dev->devpath,
324 "%s.%d", parent->devpath, port1);
326 dev->dev.parent = &parent->dev;
327 sprintf(&dev->dev.bus_id[0], "%d-%s",
328 bus->busnum, dev->devpath);
330 /* hub driver sets up TT records */
333 dev->portnum = port1;
335 dev->parent = parent;
336 INIT_LIST_HEAD(&dev->filelist);
339 mutex_init(&dev->pm_mutex);
340 INIT_DELAYED_WORK(&dev->autosuspend, usb_autosuspend_work);
341 dev->autosuspend_delay = usb_autosuspend_delay * HZ;
342 dev->connect_time = jiffies;
343 dev->active_duration = -jiffies;
345 if (root_hub) /* Root hub always ok [and always wired] */
348 dev->authorized = usb_hcd->authorized_default;
349 dev->wusb = usb_bus_is_wusb(bus)? 1 : 0;
355 * usb_get_dev - increments the reference count of the usb device structure
356 * @dev: the device being referenced
358 * Each live reference to a device should be refcounted.
360 * Drivers for USB interfaces should normally record such references in
361 * their probe() methods, when they bind to an interface, and release
362 * them by calling usb_put_dev(), in their disconnect() methods.
364 * A pointer to the device with the incremented reference counter is returned.
366 struct usb_device *usb_get_dev(struct usb_device *dev)
369 get_device(&dev->dev);
374 * usb_put_dev - release a use of the usb device structure
375 * @dev: device that's been disconnected
377 * Must be called when a user of a device is finished with it. When the last
378 * user of the device calls this function, the memory of the device is freed.
380 void usb_put_dev(struct usb_device *dev)
383 put_device(&dev->dev);
387 * usb_get_intf - increments the reference count of the usb interface structure
388 * @intf: the interface being referenced
390 * Each live reference to a interface must be refcounted.
392 * Drivers for USB interfaces should normally record such references in
393 * their probe() methods, when they bind to an interface, and release
394 * them by calling usb_put_intf(), in their disconnect() methods.
396 * A pointer to the interface with the incremented reference counter is
399 struct usb_interface *usb_get_intf(struct usb_interface *intf)
402 get_device(&intf->dev);
407 * usb_put_intf - release a use of the usb interface structure
408 * @intf: interface that's been decremented
410 * Must be called when a user of an interface is finished with it. When the
411 * last user of the interface calls this function, the memory of the interface
414 void usb_put_intf(struct usb_interface *intf)
417 put_device(&intf->dev);
421 /* USB device locking
423 * USB devices and interfaces are locked using the semaphore in their
424 * embedded struct device. The hub driver guarantees that whenever a
425 * device is connected or disconnected, drivers are called with the
426 * USB device locked as well as their particular interface.
428 * Complications arise when several devices are to be locked at the same
429 * time. Only hub-aware drivers that are part of usbcore ever have to
430 * do this; nobody else needs to worry about it. The rule for locking
433 * When locking both a device and its parent, always lock the
438 * usb_lock_device_for_reset - cautiously acquire the lock for a
439 * usb device structure
440 * @udev: device that's being locked
441 * @iface: interface bound to the driver making the request (optional)
443 * Attempts to acquire the device lock, but fails if the device is
444 * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
445 * is neither BINDING nor BOUND. Rather than sleeping to wait for the
446 * lock, the routine polls repeatedly. This is to prevent deadlock with
447 * disconnect; in some drivers (such as usb-storage) the disconnect()
448 * or suspend() method will block waiting for a device reset to complete.
450 * Returns a negative error code for failure, otherwise 1 or 0 to indicate
451 * that the device will or will not have to be unlocked. (0 can be
452 * returned when an interface is given and is BINDING, because in that
453 * case the driver already owns the device lock.)
455 int usb_lock_device_for_reset(struct usb_device *udev,
456 const struct usb_interface *iface)
458 unsigned long jiffies_expire = jiffies + HZ;
460 if (udev->state == USB_STATE_NOTATTACHED)
462 if (udev->state == USB_STATE_SUSPENDED)
463 return -EHOSTUNREACH;
465 switch (iface->condition) {
466 case USB_INTERFACE_BINDING:
468 case USB_INTERFACE_BOUND:
475 while (usb_trylock_device(udev) != 0) {
477 /* If we can't acquire the lock after waiting one second,
478 * we're probably deadlocked */
479 if (time_after(jiffies, jiffies_expire))
483 if (udev->state == USB_STATE_NOTATTACHED)
485 if (udev->state == USB_STATE_SUSPENDED)
486 return -EHOSTUNREACH;
487 if (iface && iface->condition != USB_INTERFACE_BOUND)
494 static struct usb_device *match_device(struct usb_device *dev,
495 u16 vendor_id, u16 product_id)
497 struct usb_device *ret_dev = NULL;
500 dev_dbg(&dev->dev, "check for vendor %04x, product %04x ...\n",
501 le16_to_cpu(dev->descriptor.idVendor),
502 le16_to_cpu(dev->descriptor.idProduct));
504 /* see if this device matches */
505 if ((vendor_id == le16_to_cpu(dev->descriptor.idVendor)) &&
506 (product_id == le16_to_cpu(dev->descriptor.idProduct))) {
507 dev_dbg(&dev->dev, "matched this device!\n");
508 ret_dev = usb_get_dev(dev);
512 /* look through all of the children of this device */
513 for (child = 0; child < dev->maxchild; ++child) {
514 if (dev->children[child]) {
515 usb_lock_device(dev->children[child]);
516 ret_dev = match_device(dev->children[child],
517 vendor_id, product_id);
518 usb_unlock_device(dev->children[child]);
528 * usb_find_device - find a specific usb device in the system
529 * @vendor_id: the vendor id of the device to find
530 * @product_id: the product id of the device to find
532 * Returns a pointer to a struct usb_device if such a specified usb
533 * device is present in the system currently. The usage count of the
534 * device will be incremented if a device is found. Make sure to call
535 * usb_put_dev() when the caller is finished with the device.
537 * If a device with the specified vendor and product id is not found,
540 struct usb_device *usb_find_device(u16 vendor_id, u16 product_id)
542 struct list_head *buslist;
544 struct usb_device *dev = NULL;
546 mutex_lock(&usb_bus_list_lock);
547 for (buslist = usb_bus_list.next;
548 buslist != &usb_bus_list;
549 buslist = buslist->next) {
550 bus = container_of(buslist, struct usb_bus, bus_list);
553 usb_lock_device(bus->root_hub);
554 dev = match_device(bus->root_hub, vendor_id, product_id);
555 usb_unlock_device(bus->root_hub);
560 mutex_unlock(&usb_bus_list_lock);
565 * usb_get_current_frame_number - return current bus frame number
566 * @dev: the device whose bus is being queried
568 * Returns the current frame number for the USB host controller
569 * used with the given USB device. This can be used when scheduling
570 * isochronous requests.
572 * Note that different kinds of host controller have different
573 * "scheduling horizons". While one type might support scheduling only
574 * 32 frames into the future, others could support scheduling up to
575 * 1024 frames into the future.
577 int usb_get_current_frame_number(struct usb_device *dev)
579 return usb_hcd_get_frame_number(dev);
582 /*-------------------------------------------------------------------*/
584 * __usb_get_extra_descriptor() finds a descriptor of specific type in the
585 * extra field of the interface and endpoint descriptor structs.
588 int __usb_get_extra_descriptor(char *buffer, unsigned size,
589 unsigned char type, void **ptr)
591 struct usb_descriptor_header *header;
593 while (size >= sizeof(struct usb_descriptor_header)) {
594 header = (struct usb_descriptor_header *)buffer;
596 if (header->bLength < 2) {
598 "%s: bogus descriptor, type %d length %d\n",
600 header->bDescriptorType,
605 if (header->bDescriptorType == type) {
610 buffer += header->bLength;
611 size -= header->bLength;
617 * usb_buffer_alloc - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
618 * @dev: device the buffer will be used with
619 * @size: requested buffer size
620 * @mem_flags: affect whether allocation may block
621 * @dma: used to return DMA address of buffer
623 * Return value is either null (indicating no buffer could be allocated), or
624 * the cpu-space pointer to a buffer that may be used to perform DMA to the
625 * specified device. Such cpu-space buffers are returned along with the DMA
626 * address (through the pointer provided).
628 * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
629 * to avoid behaviors like using "DMA bounce buffers", or thrashing IOMMU
630 * hardware during URB completion/resubmit. The implementation varies between
631 * platforms, depending on details of how DMA will work to this device.
632 * Using these buffers also eliminates cacheline sharing problems on
633 * architectures where CPU caches are not DMA-coherent. On systems without
634 * bus-snooping caches, these buffers are uncached.
636 * When the buffer is no longer used, free it with usb_buffer_free().
638 void *usb_buffer_alloc(
639 struct usb_device *dev,
645 if (!dev || !dev->bus)
647 return hcd_buffer_alloc(dev->bus, size, mem_flags, dma);
651 * usb_buffer_free - free memory allocated with usb_buffer_alloc()
652 * @dev: device the buffer was used with
653 * @size: requested buffer size
654 * @addr: CPU address of buffer
655 * @dma: DMA address of buffer
657 * This reclaims an I/O buffer, letting it be reused. The memory must have
658 * been allocated using usb_buffer_alloc(), and the parameters must match
659 * those provided in that allocation request.
661 void usb_buffer_free(
662 struct usb_device *dev,
668 if (!dev || !dev->bus)
672 hcd_buffer_free(dev->bus, size, addr, dma);
676 * usb_buffer_map - create DMA mapping(s) for an urb
677 * @urb: urb whose transfer_buffer/setup_packet will be mapped
679 * Return value is either null (indicating no buffer could be mapped), or
680 * the parameter. URB_NO_TRANSFER_DMA_MAP and URB_NO_SETUP_DMA_MAP are
681 * added to urb->transfer_flags if the operation succeeds. If the device
682 * is connected to this system through a non-DMA controller, this operation
685 * This call would normally be used for an urb which is reused, perhaps
686 * as the target of a large periodic transfer, with usb_buffer_dmasync()
687 * calls to synchronize memory and dma state.
689 * Reverse the effect of this call with usb_buffer_unmap().
692 struct urb *usb_buffer_map(struct urb *urb)
695 struct device *controller;
699 || !(bus = urb->dev->bus)
700 || !(controller = bus->controller))
703 if (controller->dma_mask) {
704 urb->transfer_dma = dma_map_single(controller,
705 urb->transfer_buffer, urb->transfer_buffer_length,
706 usb_pipein(urb->pipe)
707 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
708 if (usb_pipecontrol(urb->pipe))
709 urb->setup_dma = dma_map_single(controller,
711 sizeof(struct usb_ctrlrequest),
713 // FIXME generic api broken like pci, can't report errors
714 // if (urb->transfer_dma == DMA_ADDR_INVALID) return 0;
716 urb->transfer_dma = ~0;
717 urb->transfer_flags |= (URB_NO_TRANSFER_DMA_MAP
718 | URB_NO_SETUP_DMA_MAP);
723 /* XXX DISABLED, no users currently. If you wish to re-enable this
724 * XXX please determine whether the sync is to transfer ownership of
725 * XXX the buffer from device to cpu or vice verse, and thusly use the
726 * XXX appropriate _for_{cpu,device}() method. -DaveM
731 * usb_buffer_dmasync - synchronize DMA and CPU view of buffer(s)
732 * @urb: urb whose transfer_buffer/setup_packet will be synchronized
734 void usb_buffer_dmasync(struct urb *urb)
737 struct device *controller;
740 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
742 || !(bus = urb->dev->bus)
743 || !(controller = bus->controller))
746 if (controller->dma_mask) {
747 dma_sync_single(controller,
748 urb->transfer_dma, urb->transfer_buffer_length,
749 usb_pipein(urb->pipe)
750 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
751 if (usb_pipecontrol(urb->pipe))
752 dma_sync_single(controller,
754 sizeof(struct usb_ctrlrequest),
761 * usb_buffer_unmap - free DMA mapping(s) for an urb
762 * @urb: urb whose transfer_buffer will be unmapped
764 * Reverses the effect of usb_buffer_map().
767 void usb_buffer_unmap(struct urb *urb)
770 struct device *controller;
773 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
775 || !(bus = urb->dev->bus)
776 || !(controller = bus->controller))
779 if (controller->dma_mask) {
780 dma_unmap_single(controller,
781 urb->transfer_dma, urb->transfer_buffer_length,
782 usb_pipein(urb->pipe)
783 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
784 if (usb_pipecontrol(urb->pipe))
785 dma_unmap_single(controller,
787 sizeof(struct usb_ctrlrequest),
790 urb->transfer_flags &= ~(URB_NO_TRANSFER_DMA_MAP
791 | URB_NO_SETUP_DMA_MAP);
796 * usb_buffer_map_sg - create scatterlist DMA mapping(s) for an endpoint
797 * @dev: device to which the scatterlist will be mapped
798 * @is_in: mapping transfer direction
799 * @sg: the scatterlist to map
800 * @nents: the number of entries in the scatterlist
802 * Return value is either < 0 (indicating no buffers could be mapped), or
803 * the number of DMA mapping array entries in the scatterlist.
805 * The caller is responsible for placing the resulting DMA addresses from
806 * the scatterlist into URB transfer buffer pointers, and for setting the
807 * URB_NO_TRANSFER_DMA_MAP transfer flag in each of those URBs.
809 * Top I/O rates come from queuing URBs, instead of waiting for each one
810 * to complete before starting the next I/O. This is particularly easy
811 * to do with scatterlists. Just allocate and submit one URB for each DMA
812 * mapping entry returned, stopping on the first error or when all succeed.
813 * Better yet, use the usb_sg_*() calls, which do that (and more) for you.
815 * This call would normally be used when translating scatterlist requests,
816 * rather than usb_buffer_map(), since on some hardware (with IOMMUs) it
817 * may be able to coalesce mappings for improved I/O efficiency.
819 * Reverse the effect of this call with usb_buffer_unmap_sg().
821 int usb_buffer_map_sg(const struct usb_device *dev, int is_in,
822 struct scatterlist *sg, int nents)
825 struct device *controller;
829 || !(controller = bus->controller)
830 || !controller->dma_mask)
833 // FIXME generic api broken like pci, can't report errors
834 return dma_map_sg(controller, sg, nents,
835 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
838 /* XXX DISABLED, no users currently. If you wish to re-enable this
839 * XXX please determine whether the sync is to transfer ownership of
840 * XXX the buffer from device to cpu or vice verse, and thusly use the
841 * XXX appropriate _for_{cpu,device}() method. -DaveM
846 * usb_buffer_dmasync_sg - synchronize DMA and CPU view of scatterlist buffer(s)
847 * @dev: device to which the scatterlist will be mapped
848 * @is_in: mapping transfer direction
849 * @sg: the scatterlist to synchronize
850 * @n_hw_ents: the positive return value from usb_buffer_map_sg
852 * Use this when you are re-using a scatterlist's data buffers for
853 * another USB request.
855 void usb_buffer_dmasync_sg(const struct usb_device *dev, int is_in,
856 struct scatterlist *sg, int n_hw_ents)
859 struct device *controller;
863 || !(controller = bus->controller)
864 || !controller->dma_mask)
867 dma_sync_sg(controller, sg, n_hw_ents,
868 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
873 * usb_buffer_unmap_sg - free DMA mapping(s) for a scatterlist
874 * @dev: device to which the scatterlist will be mapped
875 * @is_in: mapping transfer direction
876 * @sg: the scatterlist to unmap
877 * @n_hw_ents: the positive return value from usb_buffer_map_sg
879 * Reverses the effect of usb_buffer_map_sg().
881 void usb_buffer_unmap_sg(const struct usb_device *dev, int is_in,
882 struct scatterlist *sg, int n_hw_ents)
885 struct device *controller;
889 || !(controller = bus->controller)
890 || !controller->dma_mask)
893 dma_unmap_sg(controller, sg, n_hw_ents,
894 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
897 /* format to disable USB on kernel command line is: nousb */
898 __module_param_call("", nousb, param_set_bool, param_get_bool, &nousb, 0444);
901 * for external read access to <nousb>
903 int usb_disabled(void)
911 static int __init usb_init(void)
915 pr_info("%s: USB support disabled\n", usbcore_name);
919 retval = ksuspend_usb_init();
922 retval = bus_register(&usb_bus_type);
924 goto bus_register_failed;
925 retval = usb_host_init();
927 goto host_init_failed;
928 retval = usb_major_init();
930 goto major_init_failed;
931 retval = usb_register(&usbfs_driver);
933 goto driver_register_failed;
934 retval = usb_devio_init();
936 goto usb_devio_init_failed;
937 retval = usbfs_init();
940 retval = usb_hub_init();
942 goto hub_init_failed;
943 retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
952 usb_devio_init_failed:
953 usb_deregister(&usbfs_driver);
954 driver_register_failed:
959 bus_unregister(&usb_bus_type);
961 ksuspend_usb_cleanup();
969 static void __exit usb_exit(void)
971 /* This will matter if shutdown/reboot does exitcalls. */
975 usb_deregister_device_driver(&usb_generic_driver);
978 usb_deregister(&usbfs_driver);
982 bus_unregister(&usb_bus_type);
983 ksuspend_usb_cleanup();
986 subsys_initcall(usb_init);
987 module_exit(usb_exit);
990 * USB may be built into the kernel or be built as modules.
991 * These symbols are exported for device (or host controller)
992 * driver modules to use.
995 EXPORT_SYMBOL(usb_disabled);
997 EXPORT_SYMBOL_GPL(usb_get_intf);
998 EXPORT_SYMBOL_GPL(usb_put_intf);
1000 EXPORT_SYMBOL(usb_put_dev);
1001 EXPORT_SYMBOL(usb_get_dev);
1002 EXPORT_SYMBOL(usb_hub_tt_clear_buffer);
1004 EXPORT_SYMBOL(usb_lock_device_for_reset);
1006 EXPORT_SYMBOL(usb_find_interface);
1007 EXPORT_SYMBOL(usb_ifnum_to_if);
1008 EXPORT_SYMBOL(usb_altnum_to_altsetting);
1010 EXPORT_SYMBOL(__usb_get_extra_descriptor);
1012 EXPORT_SYMBOL(usb_get_current_frame_number);
1014 EXPORT_SYMBOL(usb_buffer_alloc);
1015 EXPORT_SYMBOL(usb_buffer_free);
1018 EXPORT_SYMBOL(usb_buffer_map);
1019 EXPORT_SYMBOL(usb_buffer_dmasync);
1020 EXPORT_SYMBOL(usb_buffer_unmap);
1023 EXPORT_SYMBOL(usb_buffer_map_sg);
1025 EXPORT_SYMBOL(usb_buffer_dmasync_sg);
1027 EXPORT_SYMBOL(usb_buffer_unmap_sg);
1029 MODULE_LICENSE("GPL");