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];
99 EXPORT_SYMBOL_GPL(usb_ifnum_to_if);
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(
120 const struct usb_interface *intf,
125 for (i = 0; i < intf->num_altsetting; i++) {
126 if (intf->altsetting[i].desc.bAlternateSetting == altnum)
127 return &intf->altsetting[i];
131 EXPORT_SYMBOL_GPL(usb_altnum_to_altsetting);
133 struct find_interface_arg {
135 struct usb_interface *interface;
138 static int __find_interface(struct device *dev, void *data)
140 struct find_interface_arg *arg = data;
141 struct usb_interface *intf;
143 /* can't look at usb devices, only interfaces */
144 if (is_usb_device(dev))
147 intf = to_usb_interface(dev);
148 if (intf->minor != -1 && intf->minor == arg->minor) {
149 arg->interface = intf;
156 * usb_find_interface - find usb_interface pointer for driver and device
157 * @drv: the driver whose current configuration is considered
158 * @minor: the minor number of the desired device
160 * This walks the driver device list and returns a pointer to the interface
161 * with the matching minor. Note, this only works for devices that share the
164 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
166 struct find_interface_arg argb;
170 argb.interface = NULL;
171 /* eat the error, it will be in argb.interface */
172 retval = driver_for_each_device(&drv->drvwrap.driver, NULL, &argb,
174 return argb.interface;
176 EXPORT_SYMBOL_GPL(usb_find_interface);
179 * usb_release_dev - free a usb device structure when all users of it are finished.
180 * @dev: device that's been disconnected
182 * Will be called only by the device core when all users of this usb device are
185 static void usb_release_dev(struct device *dev)
187 struct usb_device *udev;
189 udev = to_usb_device(dev);
191 usb_destroy_configuration(udev);
192 usb_put_hcd(bus_to_hcd(udev->bus));
193 kfree(udev->product);
194 kfree(udev->manufacturer);
199 #ifdef CONFIG_HOTPLUG
200 static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
202 struct usb_device *usb_dev;
204 usb_dev = to_usb_device(dev);
206 if (add_uevent_var(env, "BUSNUM=%03d", usb_dev->bus->busnum))
209 if (add_uevent_var(env, "DEVNUM=%03d", usb_dev->devnum))
217 static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
221 #endif /* CONFIG_HOTPLUG */
223 struct device_type usb_device_type = {
224 .name = "usb_device",
225 .release = usb_release_dev,
226 .uevent = usb_dev_uevent,
231 static int ksuspend_usb_init(void)
233 /* This workqueue is supposed to be both freezable and
234 * singlethreaded. Its job doesn't justify running on more
237 ksuspend_usb_wq = create_singlethread_workqueue("ksuspend_usbd");
238 if (!ksuspend_usb_wq)
243 static void ksuspend_usb_cleanup(void)
245 destroy_workqueue(ksuspend_usb_wq);
250 #define ksuspend_usb_init() 0
251 #define ksuspend_usb_cleanup() do {} while (0)
253 #endif /* CONFIG_PM */
256 /* Returns 1 if @usb_bus is WUSB, 0 otherwise */
257 static unsigned usb_bus_is_wusb(struct usb_bus *bus)
259 struct usb_hcd *hcd = container_of(bus, struct usb_hcd, self);
260 return hcd->wireless;
265 * usb_alloc_dev - usb device constructor (usbcore-internal)
266 * @parent: hub to which device is connected; null to allocate a root hub
267 * @bus: bus used to access the device
268 * @port1: one-based index of port; ignored for root hubs
269 * Context: !in_interrupt()
271 * Only hub drivers (including virtual root hub drivers for host
272 * controllers) should ever call this.
274 * This call may not be used in a non-sleeping context.
276 struct usb_device *usb_alloc_dev(struct usb_device *parent,
277 struct usb_bus *bus, unsigned port1)
279 struct usb_device *dev;
280 struct usb_hcd *usb_hcd = container_of(bus, struct usb_hcd, self);
281 unsigned root_hub = 0;
283 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
287 if (!usb_get_hcd(bus_to_hcd(bus))) {
292 device_initialize(&dev->dev);
293 dev->dev.bus = &usb_bus_type;
294 dev->dev.type = &usb_device_type;
295 dev->dev.dma_mask = bus->controller->dma_mask;
296 set_dev_node(&dev->dev, dev_to_node(bus->controller));
297 dev->state = USB_STATE_ATTACHED;
298 atomic_set(&dev->urbnum, 0);
300 INIT_LIST_HEAD(&dev->ep0.urb_list);
301 dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
302 dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
303 /* ep0 maxpacket comes later, from device descriptor */
304 usb_enable_endpoint(dev, &dev->ep0);
307 /* Save readable and stable topology id, distinguishing devices
308 * by location for diagnostics, tools, driver model, etc. The
309 * string is a path along hub ports, from the root. Each device's
310 * dev->devpath will be stable until USB is re-cabled, and hubs
311 * are often labeled with these port numbers. The bus_id isn't
312 * as stable: bus->busnum changes easily from modprobe order,
313 * cardbus or pci hotplugging, and so on.
315 if (unlikely(!parent)) {
316 dev->devpath[0] = '0';
318 dev->dev.parent = bus->controller;
319 sprintf(&dev->dev.bus_id[0], "usb%d", bus->busnum);
322 /* match any labeling on the hubs; it's one-based */
323 if (parent->devpath[0] == '0')
324 snprintf(dev->devpath, sizeof dev->devpath,
327 snprintf(dev->devpath, sizeof dev->devpath,
328 "%s.%d", parent->devpath, port1);
330 dev->dev.parent = &parent->dev;
331 sprintf(&dev->dev.bus_id[0], "%d-%s",
332 bus->busnum, dev->devpath);
334 /* hub driver sets up TT records */
337 dev->portnum = port1;
339 dev->parent = parent;
340 INIT_LIST_HEAD(&dev->filelist);
343 mutex_init(&dev->pm_mutex);
344 INIT_DELAYED_WORK(&dev->autosuspend, usb_autosuspend_work);
345 dev->autosuspend_delay = usb_autosuspend_delay * HZ;
346 dev->connect_time = jiffies;
347 dev->active_duration = -jiffies;
349 if (root_hub) /* Root hub always ok [and always wired] */
352 dev->authorized = usb_hcd->authorized_default;
353 dev->wusb = usb_bus_is_wusb(bus)? 1 : 0;
359 * usb_get_dev - increments the reference count of the usb device structure
360 * @dev: the device being referenced
362 * Each live reference to a device should be refcounted.
364 * Drivers for USB interfaces should normally record such references in
365 * their probe() methods, when they bind to an interface, and release
366 * them by calling usb_put_dev(), in their disconnect() methods.
368 * A pointer to the device with the incremented reference counter is returned.
370 struct usb_device *usb_get_dev(struct usb_device *dev)
373 get_device(&dev->dev);
376 EXPORT_SYMBOL_GPL(usb_get_dev);
379 * usb_put_dev - release a use of the usb device structure
380 * @dev: device that's been disconnected
382 * Must be called when a user of a device is finished with it. When the last
383 * user of the device calls this function, the memory of the device is freed.
385 void usb_put_dev(struct usb_device *dev)
388 put_device(&dev->dev);
390 EXPORT_SYMBOL_GPL(usb_put_dev);
393 * usb_get_intf - increments the reference count of the usb interface structure
394 * @intf: the interface being referenced
396 * Each live reference to a interface must be refcounted.
398 * Drivers for USB interfaces should normally record such references in
399 * their probe() methods, when they bind to an interface, and release
400 * them by calling usb_put_intf(), in their disconnect() methods.
402 * A pointer to the interface with the incremented reference counter is
405 struct usb_interface *usb_get_intf(struct usb_interface *intf)
408 get_device(&intf->dev);
411 EXPORT_SYMBOL_GPL(usb_get_intf);
414 * usb_put_intf - release a use of the usb interface structure
415 * @intf: interface that's been decremented
417 * Must be called when a user of an interface is finished with it. When the
418 * last user of the interface calls this function, the memory of the interface
421 void usb_put_intf(struct usb_interface *intf)
424 put_device(&intf->dev);
426 EXPORT_SYMBOL_GPL(usb_put_intf);
428 /* USB device locking
430 * USB devices and interfaces are locked using the semaphore in their
431 * embedded struct device. The hub driver guarantees that whenever a
432 * device is connected or disconnected, drivers are called with the
433 * USB device locked as well as their particular interface.
435 * Complications arise when several devices are to be locked at the same
436 * time. Only hub-aware drivers that are part of usbcore ever have to
437 * do this; nobody else needs to worry about it. The rule for locking
440 * When locking both a device and its parent, always lock the
445 * usb_lock_device_for_reset - cautiously acquire the lock for a
446 * usb device structure
447 * @udev: device that's being locked
448 * @iface: interface bound to the driver making the request (optional)
450 * Attempts to acquire the device lock, but fails if the device is
451 * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
452 * is neither BINDING nor BOUND. Rather than sleeping to wait for the
453 * lock, the routine polls repeatedly. This is to prevent deadlock with
454 * disconnect; in some drivers (such as usb-storage) the disconnect()
455 * or suspend() method will block waiting for a device reset to complete.
457 * Returns a negative error code for failure, otherwise 1 or 0 to indicate
458 * that the device will or will not have to be unlocked. (0 can be
459 * returned when an interface is given and is BINDING, because in that
460 * case the driver already owns the device lock.)
462 int usb_lock_device_for_reset(struct usb_device *udev,
463 const struct usb_interface *iface)
465 unsigned long jiffies_expire = jiffies + HZ;
467 if (udev->state == USB_STATE_NOTATTACHED)
469 if (udev->state == USB_STATE_SUSPENDED)
470 return -EHOSTUNREACH;
472 switch (iface->condition) {
473 case USB_INTERFACE_BINDING:
475 case USB_INTERFACE_BOUND:
482 while (usb_trylock_device(udev) != 0) {
484 /* If we can't acquire the lock after waiting one second,
485 * we're probably deadlocked */
486 if (time_after(jiffies, jiffies_expire))
490 if (udev->state == USB_STATE_NOTATTACHED)
492 if (udev->state == USB_STATE_SUSPENDED)
493 return -EHOSTUNREACH;
494 if (iface && iface->condition != USB_INTERFACE_BOUND)
499 EXPORT_SYMBOL_GPL(usb_lock_device_for_reset);
501 static struct usb_device *match_device(struct usb_device *dev,
502 u16 vendor_id, u16 product_id)
504 struct usb_device *ret_dev = NULL;
507 dev_dbg(&dev->dev, "check for vendor %04x, product %04x ...\n",
508 le16_to_cpu(dev->descriptor.idVendor),
509 le16_to_cpu(dev->descriptor.idProduct));
511 /* see if this device matches */
512 if ((vendor_id == le16_to_cpu(dev->descriptor.idVendor)) &&
513 (product_id == le16_to_cpu(dev->descriptor.idProduct))) {
514 dev_dbg(&dev->dev, "matched this device!\n");
515 ret_dev = usb_get_dev(dev);
519 /* look through all of the children of this device */
520 for (child = 0; child < dev->maxchild; ++child) {
521 if (dev->children[child]) {
522 usb_lock_device(dev->children[child]);
523 ret_dev = match_device(dev->children[child],
524 vendor_id, product_id);
525 usb_unlock_device(dev->children[child]);
535 * usb_find_device - find a specific usb device in the system
536 * @vendor_id: the vendor id of the device to find
537 * @product_id: the product id of the device to find
539 * Returns a pointer to a struct usb_device if such a specified usb
540 * device is present in the system currently. The usage count of the
541 * device will be incremented if a device is found. Make sure to call
542 * usb_put_dev() when the caller is finished with the device.
544 * If a device with the specified vendor and product id is not found,
547 struct usb_device *usb_find_device(u16 vendor_id, u16 product_id)
549 struct list_head *buslist;
551 struct usb_device *dev = NULL;
553 mutex_lock(&usb_bus_list_lock);
554 for (buslist = usb_bus_list.next;
555 buslist != &usb_bus_list;
556 buslist = buslist->next) {
557 bus = container_of(buslist, struct usb_bus, bus_list);
560 usb_lock_device(bus->root_hub);
561 dev = match_device(bus->root_hub, vendor_id, product_id);
562 usb_unlock_device(bus->root_hub);
567 mutex_unlock(&usb_bus_list_lock);
572 * usb_get_current_frame_number - return current bus frame number
573 * @dev: the device whose bus is being queried
575 * Returns the current frame number for the USB host controller
576 * used with the given USB device. This can be used when scheduling
577 * isochronous requests.
579 * Note that different kinds of host controller have different
580 * "scheduling horizons". While one type might support scheduling only
581 * 32 frames into the future, others could support scheduling up to
582 * 1024 frames into the future.
584 int usb_get_current_frame_number(struct usb_device *dev)
586 return usb_hcd_get_frame_number(dev);
588 EXPORT_SYMBOL_GPL(usb_get_current_frame_number);
590 /*-------------------------------------------------------------------*/
592 * __usb_get_extra_descriptor() finds a descriptor of specific type in the
593 * extra field of the interface and endpoint descriptor structs.
596 int __usb_get_extra_descriptor(char *buffer, unsigned size,
597 unsigned char type, void **ptr)
599 struct usb_descriptor_header *header;
601 while (size >= sizeof(struct usb_descriptor_header)) {
602 header = (struct usb_descriptor_header *)buffer;
604 if (header->bLength < 2) {
606 "%s: bogus descriptor, type %d length %d\n",
608 header->bDescriptorType,
613 if (header->bDescriptorType == type) {
618 buffer += header->bLength;
619 size -= header->bLength;
623 EXPORT_SYMBOL_GPL(__usb_get_extra_descriptor);
626 * usb_buffer_alloc - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
627 * @dev: device the buffer will be used with
628 * @size: requested buffer size
629 * @mem_flags: affect whether allocation may block
630 * @dma: used to return DMA address of buffer
632 * Return value is either null (indicating no buffer could be allocated), or
633 * the cpu-space pointer to a buffer that may be used to perform DMA to the
634 * specified device. Such cpu-space buffers are returned along with the DMA
635 * address (through the pointer provided).
637 * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
638 * to avoid behaviors like using "DMA bounce buffers", or thrashing IOMMU
639 * hardware during URB completion/resubmit. The implementation varies between
640 * platforms, depending on details of how DMA will work to this device.
641 * Using these buffers also eliminates cacheline sharing problems on
642 * architectures where CPU caches are not DMA-coherent. On systems without
643 * bus-snooping caches, these buffers are uncached.
645 * When the buffer is no longer used, free it with usb_buffer_free().
647 void *usb_buffer_alloc(struct usb_device *dev, size_t size, gfp_t mem_flags,
650 if (!dev || !dev->bus)
652 return hcd_buffer_alloc(dev->bus, size, mem_flags, dma);
654 EXPORT_SYMBOL_GPL(usb_buffer_alloc);
657 * usb_buffer_free - free memory allocated with usb_buffer_alloc()
658 * @dev: device the buffer was used with
659 * @size: requested buffer size
660 * @addr: CPU address of buffer
661 * @dma: DMA address of buffer
663 * This reclaims an I/O buffer, letting it be reused. The memory must have
664 * been allocated using usb_buffer_alloc(), and the parameters must match
665 * those provided in that allocation request.
667 void usb_buffer_free(struct usb_device *dev, size_t size, void *addr,
670 if (!dev || !dev->bus)
674 hcd_buffer_free(dev->bus, size, addr, dma);
676 EXPORT_SYMBOL_GPL(usb_buffer_free);
679 * usb_buffer_map - create DMA mapping(s) for an urb
680 * @urb: urb whose transfer_buffer/setup_packet will be mapped
682 * Return value is either null (indicating no buffer could be mapped), or
683 * the parameter. URB_NO_TRANSFER_DMA_MAP and URB_NO_SETUP_DMA_MAP are
684 * added to urb->transfer_flags if the operation succeeds. If the device
685 * is connected to this system through a non-DMA controller, this operation
688 * This call would normally be used for an urb which is reused, perhaps
689 * as the target of a large periodic transfer, with usb_buffer_dmasync()
690 * calls to synchronize memory and dma state.
692 * Reverse the effect of this call with usb_buffer_unmap().
695 struct urb *usb_buffer_map(struct urb *urb)
698 struct device *controller;
702 || !(bus = urb->dev->bus)
703 || !(controller = bus->controller))
706 if (controller->dma_mask) {
707 urb->transfer_dma = dma_map_single(controller,
708 urb->transfer_buffer, urb->transfer_buffer_length,
709 usb_pipein(urb->pipe)
710 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
711 if (usb_pipecontrol(urb->pipe))
712 urb->setup_dma = dma_map_single(controller,
714 sizeof(struct usb_ctrlrequest),
716 /* FIXME generic api broken like pci, can't report errors */
717 /* if (urb->transfer_dma == DMA_ADDR_INVALID) return 0; */
719 urb->transfer_dma = ~0;
720 urb->transfer_flags |= (URB_NO_TRANSFER_DMA_MAP
721 | URB_NO_SETUP_DMA_MAP);
724 EXPORT_SYMBOL_GPL(usb_buffer_map);
727 /* XXX DISABLED, no users currently. If you wish to re-enable this
728 * XXX please determine whether the sync is to transfer ownership of
729 * XXX the buffer from device to cpu or vice verse, and thusly use the
730 * XXX appropriate _for_{cpu,device}() method. -DaveM
735 * usb_buffer_dmasync - synchronize DMA and CPU view of buffer(s)
736 * @urb: urb whose transfer_buffer/setup_packet will be synchronized
738 void usb_buffer_dmasync(struct urb *urb)
741 struct device *controller;
744 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
746 || !(bus = urb->dev->bus)
747 || !(controller = bus->controller))
750 if (controller->dma_mask) {
751 dma_sync_single(controller,
752 urb->transfer_dma, urb->transfer_buffer_length,
753 usb_pipein(urb->pipe)
754 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
755 if (usb_pipecontrol(urb->pipe))
756 dma_sync_single(controller,
758 sizeof(struct usb_ctrlrequest),
762 EXPORT_SYMBOL_GPL(usb_buffer_dmasync);
766 * usb_buffer_unmap - free DMA mapping(s) for an urb
767 * @urb: urb whose transfer_buffer will be unmapped
769 * Reverses the effect of usb_buffer_map().
772 void usb_buffer_unmap(struct urb *urb)
775 struct device *controller;
778 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
780 || !(bus = urb->dev->bus)
781 || !(controller = bus->controller))
784 if (controller->dma_mask) {
785 dma_unmap_single(controller,
786 urb->transfer_dma, urb->transfer_buffer_length,
787 usb_pipein(urb->pipe)
788 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
789 if (usb_pipecontrol(urb->pipe))
790 dma_unmap_single(controller,
792 sizeof(struct usb_ctrlrequest),
795 urb->transfer_flags &= ~(URB_NO_TRANSFER_DMA_MAP
796 | URB_NO_SETUP_DMA_MAP);
798 EXPORT_SYMBOL_GPL(usb_buffer_unmap);
802 * usb_buffer_map_sg - create scatterlist DMA mapping(s) for an endpoint
803 * @dev: device to which the scatterlist will be mapped
804 * @is_in: mapping transfer direction
805 * @sg: the scatterlist to map
806 * @nents: the number of entries in the scatterlist
808 * Return value is either < 0 (indicating no buffers could be mapped), or
809 * the number of DMA mapping array entries in the scatterlist.
811 * The caller is responsible for placing the resulting DMA addresses from
812 * the scatterlist into URB transfer buffer pointers, and for setting the
813 * URB_NO_TRANSFER_DMA_MAP transfer flag in each of those URBs.
815 * Top I/O rates come from queuing URBs, instead of waiting for each one
816 * to complete before starting the next I/O. This is particularly easy
817 * to do with scatterlists. Just allocate and submit one URB for each DMA
818 * mapping entry returned, stopping on the first error or when all succeed.
819 * Better yet, use the usb_sg_*() calls, which do that (and more) for you.
821 * This call would normally be used when translating scatterlist requests,
822 * rather than usb_buffer_map(), since on some hardware (with IOMMUs) it
823 * may be able to coalesce mappings for improved I/O efficiency.
825 * Reverse the effect of this call with usb_buffer_unmap_sg().
827 int usb_buffer_map_sg(const struct usb_device *dev, int is_in,
828 struct scatterlist *sg, int nents)
831 struct device *controller;
835 || !(controller = bus->controller)
836 || !controller->dma_mask)
839 /* FIXME generic api broken like pci, can't report errors */
840 return dma_map_sg(controller, sg, nents,
841 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
843 EXPORT_SYMBOL_GPL(usb_buffer_map_sg);
845 /* XXX DISABLED, no users currently. If you wish to re-enable this
846 * XXX please determine whether the sync is to transfer ownership of
847 * XXX the buffer from device to cpu or vice verse, and thusly use the
848 * XXX appropriate _for_{cpu,device}() method. -DaveM
853 * usb_buffer_dmasync_sg - synchronize DMA and CPU view of scatterlist buffer(s)
854 * @dev: device to which the scatterlist will be mapped
855 * @is_in: mapping transfer direction
856 * @sg: the scatterlist to synchronize
857 * @n_hw_ents: the positive return value from usb_buffer_map_sg
859 * Use this when you are re-using a scatterlist's data buffers for
860 * another USB request.
862 void usb_buffer_dmasync_sg(const struct usb_device *dev, int is_in,
863 struct scatterlist *sg, int n_hw_ents)
866 struct device *controller;
870 || !(controller = bus->controller)
871 || !controller->dma_mask)
874 dma_sync_sg(controller, sg, n_hw_ents,
875 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
877 EXPORT_SYMBOL_GPL(usb_buffer_dmasync_sg);
881 * usb_buffer_unmap_sg - free DMA mapping(s) for a scatterlist
882 * @dev: device to which the scatterlist will be mapped
883 * @is_in: mapping transfer direction
884 * @sg: the scatterlist to unmap
885 * @n_hw_ents: the positive return value from usb_buffer_map_sg
887 * Reverses the effect of usb_buffer_map_sg().
889 void usb_buffer_unmap_sg(const struct usb_device *dev, int is_in,
890 struct scatterlist *sg, int n_hw_ents)
893 struct device *controller;
897 || !(controller = bus->controller)
898 || !controller->dma_mask)
901 dma_unmap_sg(controller, sg, n_hw_ents,
902 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
904 EXPORT_SYMBOL_GPL(usb_buffer_unmap_sg);
906 /* format to disable USB on kernel command line is: nousb */
907 __module_param_call("", nousb, param_set_bool, param_get_bool, &nousb, 0444);
910 * for external read access to <nousb>
912 int usb_disabled(void)
916 EXPORT_SYMBOL_GPL(usb_disabled);
921 static int __init usb_init(void)
925 pr_info("%s: USB support disabled\n", usbcore_name);
929 retval = ksuspend_usb_init();
932 retval = bus_register(&usb_bus_type);
934 goto bus_register_failed;
935 retval = usb_host_init();
937 goto host_init_failed;
938 retval = usb_major_init();
940 goto major_init_failed;
941 retval = usb_register(&usbfs_driver);
943 goto driver_register_failed;
944 retval = usb_devio_init();
946 goto usb_devio_init_failed;
947 retval = usbfs_init();
950 retval = usb_hub_init();
952 goto hub_init_failed;
953 retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
962 usb_devio_init_failed:
963 usb_deregister(&usbfs_driver);
964 driver_register_failed:
969 bus_unregister(&usb_bus_type);
971 ksuspend_usb_cleanup();
979 static void __exit usb_exit(void)
981 /* This will matter if shutdown/reboot does exitcalls. */
985 usb_deregister_device_driver(&usb_generic_driver);
988 usb_deregister(&usbfs_driver);
992 bus_unregister(&usb_bus_type);
993 ksuspend_usb_cleanup();
996 subsys_initcall(usb_init);
997 module_exit(usb_exit);
998 MODULE_LICENSE("GPL");