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/string.h>
26 #include <linux/bitops.h>
27 #include <linux/slab.h>
28 #include <linux/interrupt.h> /* for in_interrupt() */
29 #include <linux/kmod.h>
30 #include <linux/init.h>
31 #include <linux/spinlock.h>
32 #include <linux/errno.h>
33 #include <linux/smp_lock.h>
34 #include <linux/usb.h>
35 #include <linux/mutex.h>
36 #include <linux/workqueue.h>
39 #include <asm/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 struct workqueue_struct *ksuspend_usb_wq; /* For autosuspend */
55 * usb_ifnum_to_if - get the interface object with a given interface number
56 * @dev: the device whose current configuration is considered
57 * @ifnum: the desired interface
59 * This walks the device descriptor for the currently active configuration
60 * and returns a pointer to the interface with that particular interface
63 * Note that configuration descriptors are not required to assign interface
64 * numbers sequentially, so that it would be incorrect to assume that
65 * the first interface in that descriptor corresponds to interface zero.
66 * This routine helps device drivers avoid such mistakes.
67 * However, you should make sure that you do the right thing with any
68 * alternate settings available for this interfaces.
70 * Don't call this function unless you are bound to one of the interfaces
71 * on this device or you have locked the device!
73 struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
76 struct usb_host_config *config = dev->actconfig;
81 for (i = 0; i < config->desc.bNumInterfaces; i++)
82 if (config->interface[i]->altsetting[0]
83 .desc.bInterfaceNumber == ifnum)
84 return config->interface[i];
90 * usb_altnum_to_altsetting - get the altsetting structure with a given
91 * alternate setting number.
92 * @intf: the interface containing the altsetting in question
93 * @altnum: the desired alternate setting number
95 * This searches the altsetting array of the specified interface for
96 * an entry with the correct bAlternateSetting value and returns a pointer
97 * to that entry, or null.
99 * Note that altsettings need not be stored sequentially by number, so
100 * it would be incorrect to assume that the first altsetting entry in
101 * the array corresponds to altsetting zero. This routine helps device
102 * drivers avoid such mistakes.
104 * Don't call this function unless you are bound to the intf interface
105 * or you have locked the device!
107 struct usb_host_interface *usb_altnum_to_altsetting(const struct usb_interface *intf,
112 for (i = 0; i < intf->num_altsetting; i++) {
113 if (intf->altsetting[i].desc.bAlternateSetting == altnum)
114 return &intf->altsetting[i];
119 struct find_interface_arg {
121 struct usb_interface *interface;
124 static int __find_interface(struct device * dev, void * data)
126 struct find_interface_arg *arg = data;
127 struct usb_interface *intf;
129 /* can't look at usb devices, only interfaces */
130 if (is_usb_device(dev))
133 intf = to_usb_interface(dev);
134 if (intf->minor != -1 && intf->minor == arg->minor) {
135 arg->interface = intf;
142 * usb_find_interface - find usb_interface pointer for driver and device
143 * @drv: the driver whose current configuration is considered
144 * @minor: the minor number of the desired device
146 * This walks the driver device list and returns a pointer to the interface
147 * with the matching minor. Note, this only works for devices that share the
150 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
152 struct find_interface_arg argb;
156 argb.interface = NULL;
157 /* eat the error, it will be in argb.interface */
158 retval = driver_for_each_device(&drv->drvwrap.driver, NULL, &argb,
160 return argb.interface;
164 * usb_release_dev - free a usb device structure when all users of it are finished.
165 * @dev: device that's been disconnected
167 * Will be called only by the device core when all users of this usb device are
170 static void usb_release_dev(struct device *dev)
172 struct usb_device *udev;
174 udev = to_usb_device(dev);
176 #ifdef CONFIG_USB_SUSPEND
177 cancel_delayed_work(&udev->autosuspend);
178 flush_workqueue(ksuspend_usb_wq);
180 usb_destroy_configuration(udev);
181 usb_put_hcd(bus_to_hcd(udev->bus));
182 kfree(udev->product);
183 kfree(udev->manufacturer);
190 static int ksuspend_usb_init(void)
192 ksuspend_usb_wq = create_singlethread_workqueue("ksuspend_usbd");
193 if (!ksuspend_usb_wq)
198 static void ksuspend_usb_cleanup(void)
200 destroy_workqueue(ksuspend_usb_wq);
205 #define ksuspend_usb_init() 0
206 #define ksuspend_usb_cleanup() do {} while (0)
210 #ifdef CONFIG_USB_SUSPEND
212 /* usb_autosuspend_work - callback routine to autosuspend a USB device */
213 static void usb_autosuspend_work(struct work_struct *work)
215 struct usb_device *udev =
216 container_of(work, struct usb_device, autosuspend.work);
220 usb_suspend_both(udev, PMSG_SUSPEND);
226 static void usb_autosuspend_work(struct work_struct *work)
232 * usb_alloc_dev - usb device constructor (usbcore-internal)
233 * @parent: hub to which device is connected; null to allocate a root hub
234 * @bus: bus used to access the device
235 * @port1: one-based index of port; ignored for root hubs
236 * Context: !in_interrupt ()
238 * Only hub drivers (including virtual root hub drivers for host
239 * controllers) should ever call this.
241 * This call may not be used in a non-sleeping context.
244 usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port1)
246 struct usb_device *dev;
248 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
252 if (!usb_get_hcd(bus_to_hcd(bus))) {
257 device_initialize(&dev->dev);
258 dev->dev.bus = &usb_bus_type;
259 dev->dev.dma_mask = bus->controller->dma_mask;
260 dev->dev.release = usb_release_dev;
261 dev->state = USB_STATE_ATTACHED;
263 /* This magic assignment distinguishes devices from interfaces */
264 dev->dev.platform_data = &usb_generic_driver;
266 INIT_LIST_HEAD(&dev->ep0.urb_list);
267 dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
268 dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
269 /* ep0 maxpacket comes later, from device descriptor */
270 dev->ep_in[0] = dev->ep_out[0] = &dev->ep0;
272 /* Save readable and stable topology id, distinguishing devices
273 * by location for diagnostics, tools, driver model, etc. The
274 * string is a path along hub ports, from the root. Each device's
275 * dev->devpath will be stable until USB is re-cabled, and hubs
276 * are often labeled with these port numbers. The bus_id isn't
277 * as stable: bus->busnum changes easily from modprobe order,
278 * cardbus or pci hotplugging, and so on.
280 if (unlikely (!parent)) {
281 dev->devpath [0] = '0';
283 dev->dev.parent = bus->controller;
284 sprintf (&dev->dev.bus_id[0], "usb%d", bus->busnum);
286 /* match any labeling on the hubs; it's one-based */
287 if (parent->devpath [0] == '0')
288 snprintf (dev->devpath, sizeof dev->devpath,
291 snprintf (dev->devpath, sizeof dev->devpath,
292 "%s.%d", parent->devpath, port1);
294 dev->dev.parent = &parent->dev;
295 sprintf (&dev->dev.bus_id[0], "%d-%s",
296 bus->busnum, dev->devpath);
298 /* hub driver sets up TT records */
301 dev->portnum = port1;
303 dev->parent = parent;
304 INIT_LIST_HEAD(&dev->filelist);
307 mutex_init(&dev->pm_mutex);
308 INIT_DELAYED_WORK(&dev->autosuspend, usb_autosuspend_work);
314 * usb_get_dev - increments the reference count of the usb device structure
315 * @dev: the device being referenced
317 * Each live reference to a device should be refcounted.
319 * Drivers for USB interfaces should normally record such references in
320 * their probe() methods, when they bind to an interface, and release
321 * them by calling usb_put_dev(), in their disconnect() methods.
323 * A pointer to the device with the incremented reference counter is returned.
325 struct usb_device *usb_get_dev(struct usb_device *dev)
328 get_device(&dev->dev);
333 * usb_put_dev - release a use of the usb device structure
334 * @dev: device that's been disconnected
336 * Must be called when a user of a device is finished with it. When the last
337 * user of the device calls this function, the memory of the device is freed.
339 void usb_put_dev(struct usb_device *dev)
342 put_device(&dev->dev);
346 * usb_get_intf - increments the reference count of the usb interface structure
347 * @intf: the interface being referenced
349 * Each live reference to a interface must be refcounted.
351 * Drivers for USB interfaces should normally record such references in
352 * their probe() methods, when they bind to an interface, and release
353 * them by calling usb_put_intf(), in their disconnect() methods.
355 * A pointer to the interface with the incremented reference counter is
358 struct usb_interface *usb_get_intf(struct usb_interface *intf)
361 get_device(&intf->dev);
366 * usb_put_intf - release a use of the usb interface structure
367 * @intf: interface that's been decremented
369 * Must be called when a user of an interface is finished with it. When the
370 * last user of the interface calls this function, the memory of the interface
373 void usb_put_intf(struct usb_interface *intf)
376 put_device(&intf->dev);
380 /* USB device locking
382 * USB devices and interfaces are locked using the semaphore in their
383 * embedded struct device. The hub driver guarantees that whenever a
384 * device is connected or disconnected, drivers are called with the
385 * USB device locked as well as their particular interface.
387 * Complications arise when several devices are to be locked at the same
388 * time. Only hub-aware drivers that are part of usbcore ever have to
389 * do this; nobody else needs to worry about it. The rule for locking
392 * When locking both a device and its parent, always lock the
397 * usb_lock_device_for_reset - cautiously acquire the lock for a
398 * usb device structure
399 * @udev: device that's being locked
400 * @iface: interface bound to the driver making the request (optional)
402 * Attempts to acquire the device lock, but fails if the device is
403 * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
404 * is neither BINDING nor BOUND. Rather than sleeping to wait for the
405 * lock, the routine polls repeatedly. This is to prevent deadlock with
406 * disconnect; in some drivers (such as usb-storage) the disconnect()
407 * or suspend() method will block waiting for a device reset to complete.
409 * Returns a negative error code for failure, otherwise 1 or 0 to indicate
410 * that the device will or will not have to be unlocked. (0 can be
411 * returned when an interface is given and is BINDING, because in that
412 * case the driver already owns the device lock.)
414 int usb_lock_device_for_reset(struct usb_device *udev,
415 const struct usb_interface *iface)
417 unsigned long jiffies_expire = jiffies + HZ;
419 if (udev->state == USB_STATE_NOTATTACHED)
421 if (udev->state == USB_STATE_SUSPENDED)
422 return -EHOSTUNREACH;
424 switch (iface->condition) {
425 case USB_INTERFACE_BINDING:
427 case USB_INTERFACE_BOUND:
434 while (usb_trylock_device(udev) != 0) {
436 /* If we can't acquire the lock after waiting one second,
437 * we're probably deadlocked */
438 if (time_after(jiffies, jiffies_expire))
442 if (udev->state == USB_STATE_NOTATTACHED)
444 if (udev->state == USB_STATE_SUSPENDED)
445 return -EHOSTUNREACH;
446 if (iface && iface->condition != USB_INTERFACE_BOUND)
453 static struct usb_device *match_device(struct usb_device *dev,
454 u16 vendor_id, u16 product_id)
456 struct usb_device *ret_dev = NULL;
459 dev_dbg(&dev->dev, "check for vendor %04x, product %04x ...\n",
460 le16_to_cpu(dev->descriptor.idVendor),
461 le16_to_cpu(dev->descriptor.idProduct));
463 /* see if this device matches */
464 if ((vendor_id == le16_to_cpu(dev->descriptor.idVendor)) &&
465 (product_id == le16_to_cpu(dev->descriptor.idProduct))) {
466 dev_dbg (&dev->dev, "matched this device!\n");
467 ret_dev = usb_get_dev(dev);
471 /* look through all of the children of this device */
472 for (child = 0; child < dev->maxchild; ++child) {
473 if (dev->children[child]) {
474 usb_lock_device(dev->children[child]);
475 ret_dev = match_device(dev->children[child],
476 vendor_id, product_id);
477 usb_unlock_device(dev->children[child]);
487 * usb_find_device - find a specific usb device in the system
488 * @vendor_id: the vendor id of the device to find
489 * @product_id: the product id of the device to find
491 * Returns a pointer to a struct usb_device if such a specified usb
492 * device is present in the system currently. The usage count of the
493 * device will be incremented if a device is found. Make sure to call
494 * usb_put_dev() when the caller is finished with the device.
496 * If a device with the specified vendor and product id is not found,
499 struct usb_device *usb_find_device(u16 vendor_id, u16 product_id)
501 struct list_head *buslist;
503 struct usb_device *dev = NULL;
505 mutex_lock(&usb_bus_list_lock);
506 for (buslist = usb_bus_list.next;
507 buslist != &usb_bus_list;
508 buslist = buslist->next) {
509 bus = container_of(buslist, struct usb_bus, bus_list);
512 usb_lock_device(bus->root_hub);
513 dev = match_device(bus->root_hub, vendor_id, product_id);
514 usb_unlock_device(bus->root_hub);
519 mutex_unlock(&usb_bus_list_lock);
524 * usb_get_current_frame_number - return current bus frame number
525 * @dev: the device whose bus is being queried
527 * Returns the current frame number for the USB host controller
528 * used with the given USB device. This can be used when scheduling
529 * isochronous requests.
531 * Note that different kinds of host controller have different
532 * "scheduling horizons". While one type might support scheduling only
533 * 32 frames into the future, others could support scheduling up to
534 * 1024 frames into the future.
536 int usb_get_current_frame_number(struct usb_device *dev)
538 return usb_hcd_get_frame_number (dev);
542 * usb_endpoint_dir_in - check if the endpoint has IN direction
543 * @epd: endpoint to be checked
545 * Returns true if the endpoint is of type IN, otherwise it returns false.
547 int usb_endpoint_dir_in(const struct usb_endpoint_descriptor *epd)
549 return ((epd->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_IN);
553 * usb_endpoint_dir_out - check if the endpoint has OUT direction
554 * @epd: endpoint to be checked
556 * Returns true if the endpoint is of type OUT, otherwise it returns false.
558 int usb_endpoint_dir_out(const struct usb_endpoint_descriptor *epd)
560 return ((epd->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT);
564 * usb_endpoint_xfer_bulk - check if the endpoint has bulk transfer type
565 * @epd: endpoint to be checked
567 * Returns true if the endpoint is of type bulk, otherwise it returns false.
569 int usb_endpoint_xfer_bulk(const struct usb_endpoint_descriptor *epd)
571 return ((epd->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
572 USB_ENDPOINT_XFER_BULK);
576 * usb_endpoint_xfer_int - check if the endpoint has interrupt transfer type
577 * @epd: endpoint to be checked
579 * Returns true if the endpoint is of type interrupt, otherwise it returns
582 int usb_endpoint_xfer_int(const struct usb_endpoint_descriptor *epd)
584 return ((epd->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
585 USB_ENDPOINT_XFER_INT);
589 * usb_endpoint_xfer_isoc - check if the endpoint has isochronous transfer type
590 * @epd: endpoint to be checked
592 * Returns true if the endpoint is of type isochronous, otherwise it returns
595 int usb_endpoint_xfer_isoc(const struct usb_endpoint_descriptor *epd)
597 return ((epd->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
598 USB_ENDPOINT_XFER_ISOC);
602 * usb_endpoint_is_bulk_in - check if the endpoint is bulk IN
603 * @epd: endpoint to be checked
605 * Returns true if the endpoint has bulk transfer type and IN direction,
606 * otherwise it returns false.
608 int usb_endpoint_is_bulk_in(const struct usb_endpoint_descriptor *epd)
610 return (usb_endpoint_xfer_bulk(epd) && usb_endpoint_dir_in(epd));
614 * usb_endpoint_is_bulk_out - check if the endpoint is bulk OUT
615 * @epd: endpoint to be checked
617 * Returns true if the endpoint has bulk transfer type and OUT direction,
618 * otherwise it returns false.
620 int usb_endpoint_is_bulk_out(const struct usb_endpoint_descriptor *epd)
622 return (usb_endpoint_xfer_bulk(epd) && usb_endpoint_dir_out(epd));
626 * usb_endpoint_is_int_in - check if the endpoint is interrupt IN
627 * @epd: endpoint to be checked
629 * Returns true if the endpoint has interrupt transfer type and IN direction,
630 * otherwise it returns false.
632 int usb_endpoint_is_int_in(const struct usb_endpoint_descriptor *epd)
634 return (usb_endpoint_xfer_int(epd) && usb_endpoint_dir_in(epd));
638 * usb_endpoint_is_int_out - check if the endpoint is interrupt OUT
639 * @epd: endpoint to be checked
641 * Returns true if the endpoint has interrupt transfer type and OUT direction,
642 * otherwise it returns false.
644 int usb_endpoint_is_int_out(const struct usb_endpoint_descriptor *epd)
646 return (usb_endpoint_xfer_int(epd) && usb_endpoint_dir_out(epd));
650 * usb_endpoint_is_isoc_in - check if the endpoint is isochronous IN
651 * @epd: endpoint to be checked
653 * Returns true if the endpoint has isochronous transfer type and IN direction,
654 * otherwise it returns false.
656 int usb_endpoint_is_isoc_in(const struct usb_endpoint_descriptor *epd)
658 return (usb_endpoint_xfer_isoc(epd) && usb_endpoint_dir_in(epd));
662 * usb_endpoint_is_isoc_out - check if the endpoint is isochronous OUT
663 * @epd: endpoint to be checked
665 * Returns true if the endpoint has isochronous transfer type and OUT direction,
666 * otherwise it returns false.
668 int usb_endpoint_is_isoc_out(const struct usb_endpoint_descriptor *epd)
670 return (usb_endpoint_xfer_isoc(epd) && usb_endpoint_dir_out(epd));
673 /*-------------------------------------------------------------------*/
675 * __usb_get_extra_descriptor() finds a descriptor of specific type in the
676 * extra field of the interface and endpoint descriptor structs.
679 int __usb_get_extra_descriptor(char *buffer, unsigned size,
680 unsigned char type, void **ptr)
682 struct usb_descriptor_header *header;
684 while (size >= sizeof(struct usb_descriptor_header)) {
685 header = (struct usb_descriptor_header *)buffer;
687 if (header->bLength < 2) {
689 "%s: bogus descriptor, type %d length %d\n",
691 header->bDescriptorType,
696 if (header->bDescriptorType == type) {
701 buffer += header->bLength;
702 size -= header->bLength;
708 * usb_buffer_alloc - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
709 * @dev: device the buffer will be used with
710 * @size: requested buffer size
711 * @mem_flags: affect whether allocation may block
712 * @dma: used to return DMA address of buffer
714 * Return value is either null (indicating no buffer could be allocated), or
715 * the cpu-space pointer to a buffer that may be used to perform DMA to the
716 * specified device. Such cpu-space buffers are returned along with the DMA
717 * address (through the pointer provided).
719 * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
720 * to avoid behaviors like using "DMA bounce buffers", or tying down I/O
721 * mapping hardware for long idle periods. The implementation varies between
722 * platforms, depending on details of how DMA will work to this device.
723 * Using these buffers also helps prevent cacheline sharing problems on
724 * architectures where CPU caches are not DMA-coherent.
726 * When the buffer is no longer used, free it with usb_buffer_free().
728 void *usb_buffer_alloc (
729 struct usb_device *dev,
735 if (!dev || !dev->bus)
737 return hcd_buffer_alloc (dev->bus, size, mem_flags, dma);
741 * usb_buffer_free - free memory allocated with usb_buffer_alloc()
742 * @dev: device the buffer was used with
743 * @size: requested buffer size
744 * @addr: CPU address of buffer
745 * @dma: DMA address of buffer
747 * This reclaims an I/O buffer, letting it be reused. The memory must have
748 * been allocated using usb_buffer_alloc(), and the parameters must match
749 * those provided in that allocation request.
751 void usb_buffer_free (
752 struct usb_device *dev,
758 if (!dev || !dev->bus)
762 hcd_buffer_free (dev->bus, size, addr, dma);
766 * usb_buffer_map - create DMA mapping(s) for an urb
767 * @urb: urb whose transfer_buffer/setup_packet will be mapped
769 * Return value is either null (indicating no buffer could be mapped), or
770 * the parameter. URB_NO_TRANSFER_DMA_MAP and URB_NO_SETUP_DMA_MAP are
771 * added to urb->transfer_flags if the operation succeeds. If the device
772 * is connected to this system through a non-DMA controller, this operation
775 * This call would normally be used for an urb which is reused, perhaps
776 * as the target of a large periodic transfer, with usb_buffer_dmasync()
777 * calls to synchronize memory and dma state.
779 * Reverse the effect of this call with usb_buffer_unmap().
782 struct urb *usb_buffer_map (struct urb *urb)
785 struct device *controller;
789 || !(bus = urb->dev->bus)
790 || !(controller = bus->controller))
793 if (controller->dma_mask) {
794 urb->transfer_dma = dma_map_single (controller,
795 urb->transfer_buffer, urb->transfer_buffer_length,
796 usb_pipein (urb->pipe)
797 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
798 if (usb_pipecontrol (urb->pipe))
799 urb->setup_dma = dma_map_single (controller,
801 sizeof (struct usb_ctrlrequest),
803 // FIXME generic api broken like pci, can't report errors
804 // if (urb->transfer_dma == DMA_ADDR_INVALID) return 0;
806 urb->transfer_dma = ~0;
807 urb->transfer_flags |= (URB_NO_TRANSFER_DMA_MAP
808 | URB_NO_SETUP_DMA_MAP);
813 /* XXX DISABLED, no users currently. If you wish to re-enable this
814 * XXX please determine whether the sync is to transfer ownership of
815 * XXX the buffer from device to cpu or vice verse, and thusly use the
816 * XXX appropriate _for_{cpu,device}() method. -DaveM
821 * usb_buffer_dmasync - synchronize DMA and CPU view of buffer(s)
822 * @urb: urb whose transfer_buffer/setup_packet will be synchronized
824 void usb_buffer_dmasync (struct urb *urb)
827 struct device *controller;
830 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
832 || !(bus = urb->dev->bus)
833 || !(controller = bus->controller))
836 if (controller->dma_mask) {
837 dma_sync_single (controller,
838 urb->transfer_dma, urb->transfer_buffer_length,
839 usb_pipein (urb->pipe)
840 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
841 if (usb_pipecontrol (urb->pipe))
842 dma_sync_single (controller,
844 sizeof (struct usb_ctrlrequest),
851 * usb_buffer_unmap - free DMA mapping(s) for an urb
852 * @urb: urb whose transfer_buffer will be unmapped
854 * Reverses the effect of usb_buffer_map().
857 void usb_buffer_unmap (struct urb *urb)
860 struct device *controller;
863 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
865 || !(bus = urb->dev->bus)
866 || !(controller = bus->controller))
869 if (controller->dma_mask) {
870 dma_unmap_single (controller,
871 urb->transfer_dma, urb->transfer_buffer_length,
872 usb_pipein (urb->pipe)
873 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
874 if (usb_pipecontrol (urb->pipe))
875 dma_unmap_single (controller,
877 sizeof (struct usb_ctrlrequest),
880 urb->transfer_flags &= ~(URB_NO_TRANSFER_DMA_MAP
881 | URB_NO_SETUP_DMA_MAP);
886 * usb_buffer_map_sg - create scatterlist DMA mapping(s) for an endpoint
887 * @dev: device to which the scatterlist will be mapped
888 * @pipe: endpoint defining the mapping direction
889 * @sg: the scatterlist to map
890 * @nents: the number of entries in the scatterlist
892 * Return value is either < 0 (indicating no buffers could be mapped), or
893 * the number of DMA mapping array entries in the scatterlist.
895 * The caller is responsible for placing the resulting DMA addresses from
896 * the scatterlist into URB transfer buffer pointers, and for setting the
897 * URB_NO_TRANSFER_DMA_MAP transfer flag in each of those URBs.
899 * Top I/O rates come from queuing URBs, instead of waiting for each one
900 * to complete before starting the next I/O. This is particularly easy
901 * to do with scatterlists. Just allocate and submit one URB for each DMA
902 * mapping entry returned, stopping on the first error or when all succeed.
903 * Better yet, use the usb_sg_*() calls, which do that (and more) for you.
905 * This call would normally be used when translating scatterlist requests,
906 * rather than usb_buffer_map(), since on some hardware (with IOMMUs) it
907 * may be able to coalesce mappings for improved I/O efficiency.
909 * Reverse the effect of this call with usb_buffer_unmap_sg().
911 int usb_buffer_map_sg(const struct usb_device *dev, unsigned pipe,
912 struct scatterlist *sg, int nents)
915 struct device *controller;
918 || usb_pipecontrol (pipe)
920 || !(controller = bus->controller)
921 || !controller->dma_mask)
924 // FIXME generic api broken like pci, can't report errors
925 return dma_map_sg (controller, sg, nents,
926 usb_pipein (pipe) ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
929 /* XXX DISABLED, no users currently. If you wish to re-enable this
930 * XXX please determine whether the sync is to transfer ownership of
931 * XXX the buffer from device to cpu or vice verse, and thusly use the
932 * XXX appropriate _for_{cpu,device}() method. -DaveM
937 * usb_buffer_dmasync_sg - synchronize DMA and CPU view of scatterlist buffer(s)
938 * @dev: device to which the scatterlist will be mapped
939 * @pipe: endpoint defining the mapping direction
940 * @sg: the scatterlist to synchronize
941 * @n_hw_ents: the positive return value from usb_buffer_map_sg
943 * Use this when you are re-using a scatterlist's data buffers for
944 * another USB request.
946 void usb_buffer_dmasync_sg(const struct usb_device *dev, unsigned pipe,
947 struct scatterlist *sg, int n_hw_ents)
950 struct device *controller;
954 || !(controller = bus->controller)
955 || !controller->dma_mask)
958 dma_sync_sg (controller, sg, n_hw_ents,
959 usb_pipein (pipe) ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
964 * usb_buffer_unmap_sg - free DMA mapping(s) for a scatterlist
965 * @dev: device to which the scatterlist will be mapped
966 * @pipe: endpoint defining the mapping direction
967 * @sg: the scatterlist to unmap
968 * @n_hw_ents: the positive return value from usb_buffer_map_sg
970 * Reverses the effect of usb_buffer_map_sg().
972 void usb_buffer_unmap_sg(const struct usb_device *dev, unsigned pipe,
973 struct scatterlist *sg, int n_hw_ents)
976 struct device *controller;
980 || !(controller = bus->controller)
981 || !controller->dma_mask)
984 dma_unmap_sg (controller, sg, n_hw_ents,
985 usb_pipein (pipe) ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
988 /* format to disable USB on kernel command line is: nousb */
989 __module_param_call("", nousb, param_set_bool, param_get_bool, &nousb, 0444);
992 * for external read access to <nousb>
994 int usb_disabled(void)
1002 static int __init usb_init(void)
1006 pr_info ("%s: USB support disabled\n", usbcore_name);
1010 retval = ksuspend_usb_init();
1013 retval = bus_register(&usb_bus_type);
1015 goto bus_register_failed;
1016 retval = usb_host_init();
1018 goto host_init_failed;
1019 retval = usb_major_init();
1021 goto major_init_failed;
1022 retval = usb_register(&usbfs_driver);
1024 goto driver_register_failed;
1025 retval = usbdev_init();
1027 goto usbdevice_init_failed;
1028 retval = usbfs_init();
1030 goto fs_init_failed;
1031 retval = usb_hub_init();
1033 goto hub_init_failed;
1034 retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
1043 usbdevice_init_failed:
1044 usb_deregister(&usbfs_driver);
1045 driver_register_failed:
1046 usb_major_cleanup();
1050 bus_unregister(&usb_bus_type);
1051 bus_register_failed:
1052 ksuspend_usb_cleanup();
1060 static void __exit usb_exit(void)
1062 /* This will matter if shutdown/reboot does exitcalls. */
1066 usb_deregister_device_driver(&usb_generic_driver);
1067 usb_major_cleanup();
1069 usb_deregister(&usbfs_driver);
1073 bus_unregister(&usb_bus_type);
1074 ksuspend_usb_cleanup();
1077 subsys_initcall(usb_init);
1078 module_exit(usb_exit);
1081 * USB may be built into the kernel or be built as modules.
1082 * These symbols are exported for device (or host controller)
1083 * driver modules to use.
1086 EXPORT_SYMBOL(usb_disabled);
1088 EXPORT_SYMBOL_GPL(usb_get_intf);
1089 EXPORT_SYMBOL_GPL(usb_put_intf);
1091 EXPORT_SYMBOL(usb_put_dev);
1092 EXPORT_SYMBOL(usb_get_dev);
1093 EXPORT_SYMBOL(usb_hub_tt_clear_buffer);
1095 EXPORT_SYMBOL(usb_lock_device_for_reset);
1097 EXPORT_SYMBOL(usb_find_interface);
1098 EXPORT_SYMBOL(usb_ifnum_to_if);
1099 EXPORT_SYMBOL(usb_altnum_to_altsetting);
1101 EXPORT_SYMBOL(__usb_get_extra_descriptor);
1103 EXPORT_SYMBOL(usb_find_device);
1104 EXPORT_SYMBOL(usb_get_current_frame_number);
1106 EXPORT_SYMBOL_GPL(usb_endpoint_dir_in);
1107 EXPORT_SYMBOL_GPL(usb_endpoint_dir_out);
1108 EXPORT_SYMBOL_GPL(usb_endpoint_xfer_bulk);
1109 EXPORT_SYMBOL_GPL(usb_endpoint_xfer_int);
1110 EXPORT_SYMBOL_GPL(usb_endpoint_xfer_isoc);
1111 EXPORT_SYMBOL_GPL(usb_endpoint_is_bulk_in);
1112 EXPORT_SYMBOL_GPL(usb_endpoint_is_bulk_out);
1113 EXPORT_SYMBOL_GPL(usb_endpoint_is_int_in);
1114 EXPORT_SYMBOL_GPL(usb_endpoint_is_int_out);
1115 EXPORT_SYMBOL_GPL(usb_endpoint_is_isoc_in);
1116 EXPORT_SYMBOL_GPL(usb_endpoint_is_isoc_out);
1118 EXPORT_SYMBOL (usb_buffer_alloc);
1119 EXPORT_SYMBOL (usb_buffer_free);
1122 EXPORT_SYMBOL (usb_buffer_map);
1123 EXPORT_SYMBOL (usb_buffer_dmasync);
1124 EXPORT_SYMBOL (usb_buffer_unmap);
1127 EXPORT_SYMBOL (usb_buffer_map_sg);
1129 EXPORT_SYMBOL (usb_buffer_dmasync_sg);
1131 EXPORT_SYMBOL (usb_buffer_unmap_sg);
1133 MODULE_LICENSE("GPL");