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>
38 #include <asm/scatterlist.h>
40 #include <linux/dma-mapping.h>
46 const char *usbcore_name = "usbcore";
48 static int nousb; /* Disable USB when built into kernel image */
52 * usb_ifnum_to_if - get the interface object with a given interface number
53 * @dev: the device whose current configuration is considered
54 * @ifnum: the desired interface
56 * This walks the device descriptor for the currently active configuration
57 * and returns a pointer to the interface with that particular interface
60 * Note that configuration descriptors are not required to assign interface
61 * numbers sequentially, so that it would be incorrect to assume that
62 * the first interface in that descriptor corresponds to interface zero.
63 * This routine helps device drivers avoid such mistakes.
64 * However, you should make sure that you do the right thing with any
65 * alternate settings available for this interfaces.
67 * Don't call this function unless you are bound to one of the interfaces
68 * on this device or you have locked the device!
70 struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
73 struct usb_host_config *config = dev->actconfig;
78 for (i = 0; i < config->desc.bNumInterfaces; i++)
79 if (config->interface[i]->altsetting[0]
80 .desc.bInterfaceNumber == ifnum)
81 return config->interface[i];
87 * usb_altnum_to_altsetting - get the altsetting structure with a given
88 * alternate setting number.
89 * @intf: the interface containing the altsetting in question
90 * @altnum: the desired alternate setting number
92 * This searches the altsetting array of the specified interface for
93 * an entry with the correct bAlternateSetting value and returns a pointer
94 * to that entry, or null.
96 * Note that altsettings need not be stored sequentially by number, so
97 * it would be incorrect to assume that the first altsetting entry in
98 * the array corresponds to altsetting zero. This routine helps device
99 * drivers avoid such mistakes.
101 * Don't call this function unless you are bound to the intf interface
102 * or you have locked the device!
104 struct usb_host_interface *usb_altnum_to_altsetting(const struct usb_interface *intf,
109 for (i = 0; i < intf->num_altsetting; i++) {
110 if (intf->altsetting[i].desc.bAlternateSetting == altnum)
111 return &intf->altsetting[i];
116 struct find_interface_arg {
118 struct usb_interface *interface;
121 static int __find_interface(struct device * dev, void * data)
123 struct find_interface_arg *arg = data;
124 struct usb_interface *intf;
126 /* can't look at usb devices, only interfaces */
127 if (is_usb_device(dev))
130 intf = to_usb_interface(dev);
131 if (intf->minor != -1 && intf->minor == arg->minor) {
132 arg->interface = intf;
139 * usb_find_interface - find usb_interface pointer for driver and device
140 * @drv: the driver whose current configuration is considered
141 * @minor: the minor number of the desired device
143 * This walks the driver device list and returns a pointer to the interface
144 * with the matching minor. Note, this only works for devices that share the
147 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
149 struct find_interface_arg argb;
153 argb.interface = NULL;
154 /* eat the error, it will be in argb.interface */
155 retval = driver_for_each_device(&drv->drvwrap.driver, NULL, &argb,
157 return argb.interface;
161 * usb_release_dev - free a usb device structure when all users of it are finished.
162 * @dev: device that's been disconnected
164 * Will be called only by the device core when all users of this usb device are
167 static void usb_release_dev(struct device *dev)
169 struct usb_device *udev;
171 udev = to_usb_device(dev);
174 cancel_delayed_work(&udev->autosuspend);
175 flush_scheduled_work();
177 usb_destroy_configuration(udev);
178 usb_put_hcd(bus_to_hcd(udev->bus));
179 kfree(udev->product);
180 kfree(udev->manufacturer);
187 /* usb_autosuspend_work - callback routine to autosuspend a USB device */
188 static void usb_autosuspend_work(void *_udev)
190 struct usb_device *udev = _udev;
192 mutex_lock_nested(&udev->pm_mutex, udev->level);
194 usb_suspend_both(udev, PMSG_SUSPEND);
195 mutex_unlock(&udev->pm_mutex);
201 * usb_alloc_dev - usb device constructor (usbcore-internal)
202 * @parent: hub to which device is connected; null to allocate a root hub
203 * @bus: bus used to access the device
204 * @port1: one-based index of port; ignored for root hubs
205 * Context: !in_interrupt ()
207 * Only hub drivers (including virtual root hub drivers for host
208 * controllers) should ever call this.
210 * This call may not be used in a non-sleeping context.
213 usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port1)
215 struct usb_device *dev;
217 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
221 if (!usb_get_hcd(bus_to_hcd(bus))) {
226 device_initialize(&dev->dev);
227 dev->dev.bus = &usb_bus_type;
228 dev->dev.dma_mask = bus->controller->dma_mask;
229 dev->dev.release = usb_release_dev;
230 dev->state = USB_STATE_ATTACHED;
232 /* This magic assignment distinguishes devices from interfaces */
233 dev->dev.platform_data = &usb_generic_driver;
235 INIT_LIST_HEAD(&dev->ep0.urb_list);
236 dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
237 dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
238 /* ep0 maxpacket comes later, from device descriptor */
239 dev->ep_in[0] = dev->ep_out[0] = &dev->ep0;
241 /* Save readable and stable topology id, distinguishing devices
242 * by location for diagnostics, tools, driver model, etc. The
243 * string is a path along hub ports, from the root. Each device's
244 * dev->devpath will be stable until USB is re-cabled, and hubs
245 * are often labeled with these port numbers. The bus_id isn't
246 * as stable: bus->busnum changes easily from modprobe order,
247 * cardbus or pci hotplugging, and so on.
249 if (unlikely (!parent)) {
250 dev->devpath [0] = '0';
252 dev->dev.parent = bus->controller;
253 sprintf (&dev->dev.bus_id[0], "usb%d", bus->busnum);
255 /* match any labeling on the hubs; it's one-based */
256 if (parent->devpath [0] == '0')
257 snprintf (dev->devpath, sizeof dev->devpath,
260 snprintf (dev->devpath, sizeof dev->devpath,
261 "%s.%d", parent->devpath, port1);
263 dev->dev.parent = &parent->dev;
264 sprintf (&dev->dev.bus_id[0], "%d-%s",
265 bus->busnum, dev->devpath);
267 /* hub driver sets up TT records */
270 dev->portnum = port1;
272 dev->parent = parent;
273 INIT_LIST_HEAD(&dev->filelist);
276 mutex_init(&dev->pm_mutex);
277 INIT_WORK(&dev->autosuspend, usb_autosuspend_work, dev);
283 * usb_get_dev - increments the reference count of the usb device structure
284 * @dev: the device being referenced
286 * Each live reference to a device should be refcounted.
288 * Drivers for USB interfaces should normally record such references in
289 * their probe() methods, when they bind to an interface, and release
290 * them by calling usb_put_dev(), in their disconnect() methods.
292 * A pointer to the device with the incremented reference counter is returned.
294 struct usb_device *usb_get_dev(struct usb_device *dev)
297 get_device(&dev->dev);
302 * usb_put_dev - release a use of the usb device structure
303 * @dev: device that's been disconnected
305 * Must be called when a user of a device is finished with it. When the last
306 * user of the device calls this function, the memory of the device is freed.
308 void usb_put_dev(struct usb_device *dev)
311 put_device(&dev->dev);
315 * usb_get_intf - increments the reference count of the usb interface structure
316 * @intf: the interface being referenced
318 * Each live reference to a interface must be refcounted.
320 * Drivers for USB interfaces should normally record such references in
321 * their probe() methods, when they bind to an interface, and release
322 * them by calling usb_put_intf(), in their disconnect() methods.
324 * A pointer to the interface with the incremented reference counter is
327 struct usb_interface *usb_get_intf(struct usb_interface *intf)
330 get_device(&intf->dev);
335 * usb_put_intf - release a use of the usb interface structure
336 * @intf: interface that's been decremented
338 * Must be called when a user of an interface is finished with it. When the
339 * last user of the interface calls this function, the memory of the interface
342 void usb_put_intf(struct usb_interface *intf)
345 put_device(&intf->dev);
349 /* USB device locking
351 * USB devices and interfaces are locked using the semaphore in their
352 * embedded struct device. The hub driver guarantees that whenever a
353 * device is connected or disconnected, drivers are called with the
354 * USB device locked as well as their particular interface.
356 * Complications arise when several devices are to be locked at the same
357 * time. Only hub-aware drivers that are part of usbcore ever have to
358 * do this; nobody else needs to worry about it. The rule for locking
361 * When locking both a device and its parent, always lock the
366 * usb_lock_device_for_reset - cautiously acquire the lock for a
367 * usb device structure
368 * @udev: device that's being locked
369 * @iface: interface bound to the driver making the request (optional)
371 * Attempts to acquire the device lock, but fails if the device is
372 * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
373 * is neither BINDING nor BOUND. Rather than sleeping to wait for the
374 * lock, the routine polls repeatedly. This is to prevent deadlock with
375 * disconnect; in some drivers (such as usb-storage) the disconnect()
376 * or suspend() method will block waiting for a device reset to complete.
378 * Returns a negative error code for failure, otherwise 1 or 0 to indicate
379 * that the device will or will not have to be unlocked. (0 can be
380 * returned when an interface is given and is BINDING, because in that
381 * case the driver already owns the device lock.)
383 int usb_lock_device_for_reset(struct usb_device *udev,
384 const struct usb_interface *iface)
386 unsigned long jiffies_expire = jiffies + HZ;
388 if (udev->state == USB_STATE_NOTATTACHED)
390 if (udev->state == USB_STATE_SUSPENDED)
391 return -EHOSTUNREACH;
393 switch (iface->condition) {
394 case USB_INTERFACE_BINDING:
396 case USB_INTERFACE_BOUND:
403 while (usb_trylock_device(udev) != 0) {
405 /* If we can't acquire the lock after waiting one second,
406 * we're probably deadlocked */
407 if (time_after(jiffies, jiffies_expire))
411 if (udev->state == USB_STATE_NOTATTACHED)
413 if (udev->state == USB_STATE_SUSPENDED)
414 return -EHOSTUNREACH;
415 if (iface && iface->condition != USB_INTERFACE_BOUND)
422 static struct usb_device *match_device(struct usb_device *dev,
423 u16 vendor_id, u16 product_id)
425 struct usb_device *ret_dev = NULL;
428 dev_dbg(&dev->dev, "check for vendor %04x, product %04x ...\n",
429 le16_to_cpu(dev->descriptor.idVendor),
430 le16_to_cpu(dev->descriptor.idProduct));
432 /* see if this device matches */
433 if ((vendor_id == le16_to_cpu(dev->descriptor.idVendor)) &&
434 (product_id == le16_to_cpu(dev->descriptor.idProduct))) {
435 dev_dbg (&dev->dev, "matched this device!\n");
436 ret_dev = usb_get_dev(dev);
440 /* look through all of the children of this device */
441 for (child = 0; child < dev->maxchild; ++child) {
442 if (dev->children[child]) {
443 usb_lock_device(dev->children[child]);
444 ret_dev = match_device(dev->children[child],
445 vendor_id, product_id);
446 usb_unlock_device(dev->children[child]);
456 * usb_find_device - find a specific usb device in the system
457 * @vendor_id: the vendor id of the device to find
458 * @product_id: the product id of the device to find
460 * Returns a pointer to a struct usb_device if such a specified usb
461 * device is present in the system currently. The usage count of the
462 * device will be incremented if a device is found. Make sure to call
463 * usb_put_dev() when the caller is finished with the device.
465 * If a device with the specified vendor and product id is not found,
468 struct usb_device *usb_find_device(u16 vendor_id, u16 product_id)
470 struct list_head *buslist;
472 struct usb_device *dev = NULL;
474 mutex_lock(&usb_bus_list_lock);
475 for (buslist = usb_bus_list.next;
476 buslist != &usb_bus_list;
477 buslist = buslist->next) {
478 bus = container_of(buslist, struct usb_bus, bus_list);
481 usb_lock_device(bus->root_hub);
482 dev = match_device(bus->root_hub, vendor_id, product_id);
483 usb_unlock_device(bus->root_hub);
488 mutex_unlock(&usb_bus_list_lock);
493 * usb_get_current_frame_number - return current bus frame number
494 * @dev: the device whose bus is being queried
496 * Returns the current frame number for the USB host controller
497 * used with the given USB device. This can be used when scheduling
498 * isochronous requests.
500 * Note that different kinds of host controller have different
501 * "scheduling horizons". While one type might support scheduling only
502 * 32 frames into the future, others could support scheduling up to
503 * 1024 frames into the future.
505 int usb_get_current_frame_number(struct usb_device *dev)
507 return usb_hcd_get_frame_number (dev);
511 * usb_endpoint_dir_in - check if the endpoint has IN direction
512 * @epd: endpoint to be checked
514 * Returns true if the endpoint is of type IN, otherwise it returns false.
516 int usb_endpoint_dir_in(const struct usb_endpoint_descriptor *epd)
518 return ((epd->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_IN);
522 * usb_endpoint_dir_out - check if the endpoint has OUT direction
523 * @epd: endpoint to be checked
525 * Returns true if the endpoint is of type OUT, otherwise it returns false.
527 int usb_endpoint_dir_out(const struct usb_endpoint_descriptor *epd)
529 return ((epd->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT);
533 * usb_endpoint_xfer_bulk - check if the endpoint has bulk transfer type
534 * @epd: endpoint to be checked
536 * Returns true if the endpoint is of type bulk, otherwise it returns false.
538 int usb_endpoint_xfer_bulk(const struct usb_endpoint_descriptor *epd)
540 return ((epd->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
541 USB_ENDPOINT_XFER_BULK);
545 * usb_endpoint_xfer_int - check if the endpoint has interrupt transfer type
546 * @epd: endpoint to be checked
548 * Returns true if the endpoint is of type interrupt, otherwise it returns
551 int usb_endpoint_xfer_int(const struct usb_endpoint_descriptor *epd)
553 return ((epd->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
554 USB_ENDPOINT_XFER_INT);
558 * usb_endpoint_xfer_isoc - check if the endpoint has isochronous transfer type
559 * @epd: endpoint to be checked
561 * Returns true if the endpoint is of type isochronous, otherwise it returns
564 int usb_endpoint_xfer_isoc(const struct usb_endpoint_descriptor *epd)
566 return ((epd->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
567 USB_ENDPOINT_XFER_ISOC);
571 * usb_endpoint_is_bulk_in - check if the endpoint is bulk IN
572 * @epd: endpoint to be checked
574 * Returns true if the endpoint has bulk transfer type and IN direction,
575 * otherwise it returns false.
577 int usb_endpoint_is_bulk_in(const struct usb_endpoint_descriptor *epd)
579 return (usb_endpoint_xfer_bulk(epd) && usb_endpoint_dir_in(epd));
583 * usb_endpoint_is_bulk_out - check if the endpoint is bulk OUT
584 * @epd: endpoint to be checked
586 * Returns true if the endpoint has bulk transfer type and OUT direction,
587 * otherwise it returns false.
589 int usb_endpoint_is_bulk_out(const struct usb_endpoint_descriptor *epd)
591 return (usb_endpoint_xfer_bulk(epd) && usb_endpoint_dir_out(epd));
595 * usb_endpoint_is_int_in - check if the endpoint is interrupt IN
596 * @epd: endpoint to be checked
598 * Returns true if the endpoint has interrupt transfer type and IN direction,
599 * otherwise it returns false.
601 int usb_endpoint_is_int_in(const struct usb_endpoint_descriptor *epd)
603 return (usb_endpoint_xfer_int(epd) && usb_endpoint_dir_in(epd));
607 * usb_endpoint_is_int_out - check if the endpoint is interrupt OUT
608 * @epd: endpoint to be checked
610 * Returns true if the endpoint has interrupt transfer type and OUT direction,
611 * otherwise it returns false.
613 int usb_endpoint_is_int_out(const struct usb_endpoint_descriptor *epd)
615 return (usb_endpoint_xfer_int(epd) && usb_endpoint_dir_out(epd));
619 * usb_endpoint_is_isoc_in - check if the endpoint is isochronous IN
620 * @epd: endpoint to be checked
622 * Returns true if the endpoint has isochronous transfer type and IN direction,
623 * otherwise it returns false.
625 int usb_endpoint_is_isoc_in(const struct usb_endpoint_descriptor *epd)
627 return (usb_endpoint_xfer_isoc(epd) && usb_endpoint_dir_in(epd));
631 * usb_endpoint_is_isoc_out - check if the endpoint is isochronous OUT
632 * @epd: endpoint to be checked
634 * Returns true if the endpoint has isochronous transfer type and OUT direction,
635 * otherwise it returns false.
637 int usb_endpoint_is_isoc_out(const struct usb_endpoint_descriptor *epd)
639 return (usb_endpoint_xfer_isoc(epd) && usb_endpoint_dir_out(epd));
642 /*-------------------------------------------------------------------*/
644 * __usb_get_extra_descriptor() finds a descriptor of specific type in the
645 * extra field of the interface and endpoint descriptor structs.
648 int __usb_get_extra_descriptor(char *buffer, unsigned size,
649 unsigned char type, void **ptr)
651 struct usb_descriptor_header *header;
653 while (size >= sizeof(struct usb_descriptor_header)) {
654 header = (struct usb_descriptor_header *)buffer;
656 if (header->bLength < 2) {
658 "%s: bogus descriptor, type %d length %d\n",
660 header->bDescriptorType,
665 if (header->bDescriptorType == type) {
670 buffer += header->bLength;
671 size -= header->bLength;
677 * usb_buffer_alloc - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
678 * @dev: device the buffer will be used with
679 * @size: requested buffer size
680 * @mem_flags: affect whether allocation may block
681 * @dma: used to return DMA address of buffer
683 * Return value is either null (indicating no buffer could be allocated), or
684 * the cpu-space pointer to a buffer that may be used to perform DMA to the
685 * specified device. Such cpu-space buffers are returned along with the DMA
686 * address (through the pointer provided).
688 * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
689 * to avoid behaviors like using "DMA bounce buffers", or tying down I/O
690 * mapping hardware for long idle periods. The implementation varies between
691 * platforms, depending on details of how DMA will work to this device.
692 * Using these buffers also helps prevent cacheline sharing problems on
693 * architectures where CPU caches are not DMA-coherent.
695 * When the buffer is no longer used, free it with usb_buffer_free().
697 void *usb_buffer_alloc (
698 struct usb_device *dev,
704 if (!dev || !dev->bus)
706 return hcd_buffer_alloc (dev->bus, size, mem_flags, dma);
710 * usb_buffer_free - free memory allocated with usb_buffer_alloc()
711 * @dev: device the buffer was used with
712 * @size: requested buffer size
713 * @addr: CPU address of buffer
714 * @dma: DMA address of buffer
716 * This reclaims an I/O buffer, letting it be reused. The memory must have
717 * been allocated using usb_buffer_alloc(), and the parameters must match
718 * those provided in that allocation request.
720 void usb_buffer_free (
721 struct usb_device *dev,
727 if (!dev || !dev->bus)
731 hcd_buffer_free (dev->bus, size, addr, dma);
735 * usb_buffer_map - create DMA mapping(s) for an urb
736 * @urb: urb whose transfer_buffer/setup_packet will be mapped
738 * Return value is either null (indicating no buffer could be mapped), or
739 * the parameter. URB_NO_TRANSFER_DMA_MAP and URB_NO_SETUP_DMA_MAP are
740 * added to urb->transfer_flags if the operation succeeds. If the device
741 * is connected to this system through a non-DMA controller, this operation
744 * This call would normally be used for an urb which is reused, perhaps
745 * as the target of a large periodic transfer, with usb_buffer_dmasync()
746 * calls to synchronize memory and dma state.
748 * Reverse the effect of this call with usb_buffer_unmap().
751 struct urb *usb_buffer_map (struct urb *urb)
754 struct device *controller;
758 || !(bus = urb->dev->bus)
759 || !(controller = bus->controller))
762 if (controller->dma_mask) {
763 urb->transfer_dma = dma_map_single (controller,
764 urb->transfer_buffer, urb->transfer_buffer_length,
765 usb_pipein (urb->pipe)
766 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
767 if (usb_pipecontrol (urb->pipe))
768 urb->setup_dma = dma_map_single (controller,
770 sizeof (struct usb_ctrlrequest),
772 // FIXME generic api broken like pci, can't report errors
773 // if (urb->transfer_dma == DMA_ADDR_INVALID) return 0;
775 urb->transfer_dma = ~0;
776 urb->transfer_flags |= (URB_NO_TRANSFER_DMA_MAP
777 | URB_NO_SETUP_DMA_MAP);
782 /* XXX DISABLED, no users currently. If you wish to re-enable this
783 * XXX please determine whether the sync is to transfer ownership of
784 * XXX the buffer from device to cpu or vice verse, and thusly use the
785 * XXX appropriate _for_{cpu,device}() method. -DaveM
790 * usb_buffer_dmasync - synchronize DMA and CPU view of buffer(s)
791 * @urb: urb whose transfer_buffer/setup_packet will be synchronized
793 void usb_buffer_dmasync (struct urb *urb)
796 struct device *controller;
799 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
801 || !(bus = urb->dev->bus)
802 || !(controller = bus->controller))
805 if (controller->dma_mask) {
806 dma_sync_single (controller,
807 urb->transfer_dma, urb->transfer_buffer_length,
808 usb_pipein (urb->pipe)
809 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
810 if (usb_pipecontrol (urb->pipe))
811 dma_sync_single (controller,
813 sizeof (struct usb_ctrlrequest),
820 * usb_buffer_unmap - free DMA mapping(s) for an urb
821 * @urb: urb whose transfer_buffer will be unmapped
823 * Reverses the effect of usb_buffer_map().
826 void usb_buffer_unmap (struct urb *urb)
829 struct device *controller;
832 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
834 || !(bus = urb->dev->bus)
835 || !(controller = bus->controller))
838 if (controller->dma_mask) {
839 dma_unmap_single (controller,
840 urb->transfer_dma, urb->transfer_buffer_length,
841 usb_pipein (urb->pipe)
842 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
843 if (usb_pipecontrol (urb->pipe))
844 dma_unmap_single (controller,
846 sizeof (struct usb_ctrlrequest),
849 urb->transfer_flags &= ~(URB_NO_TRANSFER_DMA_MAP
850 | URB_NO_SETUP_DMA_MAP);
855 * usb_buffer_map_sg - create scatterlist DMA mapping(s) for an endpoint
856 * @dev: device to which the scatterlist will be mapped
857 * @pipe: endpoint defining the mapping direction
858 * @sg: the scatterlist to map
859 * @nents: the number of entries in the scatterlist
861 * Return value is either < 0 (indicating no buffers could be mapped), or
862 * the number of DMA mapping array entries in the scatterlist.
864 * The caller is responsible for placing the resulting DMA addresses from
865 * the scatterlist into URB transfer buffer pointers, and for setting the
866 * URB_NO_TRANSFER_DMA_MAP transfer flag in each of those URBs.
868 * Top I/O rates come from queuing URBs, instead of waiting for each one
869 * to complete before starting the next I/O. This is particularly easy
870 * to do with scatterlists. Just allocate and submit one URB for each DMA
871 * mapping entry returned, stopping on the first error or when all succeed.
872 * Better yet, use the usb_sg_*() calls, which do that (and more) for you.
874 * This call would normally be used when translating scatterlist requests,
875 * rather than usb_buffer_map(), since on some hardware (with IOMMUs) it
876 * may be able to coalesce mappings for improved I/O efficiency.
878 * Reverse the effect of this call with usb_buffer_unmap_sg().
880 int usb_buffer_map_sg(const struct usb_device *dev, unsigned pipe,
881 struct scatterlist *sg, int nents)
884 struct device *controller;
887 || usb_pipecontrol (pipe)
889 || !(controller = bus->controller)
890 || !controller->dma_mask)
893 // FIXME generic api broken like pci, can't report errors
894 return dma_map_sg (controller, sg, nents,
895 usb_pipein (pipe) ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
898 /* XXX DISABLED, no users currently. If you wish to re-enable this
899 * XXX please determine whether the sync is to transfer ownership of
900 * XXX the buffer from device to cpu or vice verse, and thusly use the
901 * XXX appropriate _for_{cpu,device}() method. -DaveM
906 * usb_buffer_dmasync_sg - synchronize DMA and CPU view of scatterlist buffer(s)
907 * @dev: device to which the scatterlist will be mapped
908 * @pipe: endpoint defining the mapping direction
909 * @sg: the scatterlist to synchronize
910 * @n_hw_ents: the positive return value from usb_buffer_map_sg
912 * Use this when you are re-using a scatterlist's data buffers for
913 * another USB request.
915 void usb_buffer_dmasync_sg(const struct usb_device *dev, unsigned pipe,
916 struct scatterlist *sg, int n_hw_ents)
919 struct device *controller;
923 || !(controller = bus->controller)
924 || !controller->dma_mask)
927 dma_sync_sg (controller, sg, n_hw_ents,
928 usb_pipein (pipe) ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
933 * usb_buffer_unmap_sg - free DMA mapping(s) for a scatterlist
934 * @dev: device to which the scatterlist will be mapped
935 * @pipe: endpoint defining the mapping direction
936 * @sg: the scatterlist to unmap
937 * @n_hw_ents: the positive return value from usb_buffer_map_sg
939 * Reverses the effect of usb_buffer_map_sg().
941 void usb_buffer_unmap_sg(const struct usb_device *dev, unsigned pipe,
942 struct scatterlist *sg, int n_hw_ents)
945 struct device *controller;
949 || !(controller = bus->controller)
950 || !controller->dma_mask)
953 dma_unmap_sg (controller, sg, n_hw_ents,
954 usb_pipein (pipe) ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
957 /* format to disable USB on kernel command line is: nousb */
958 __module_param_call("", nousb, param_set_bool, param_get_bool, &nousb, 0444);
961 * for external read access to <nousb>
963 int usb_disabled(void)
971 static int __init usb_init(void)
975 pr_info ("%s: USB support disabled\n", usbcore_name);
979 retval = bus_register(&usb_bus_type);
982 retval = usb_host_init();
984 goto host_init_failed;
985 retval = usb_major_init();
987 goto major_init_failed;
988 retval = usb_register(&usbfs_driver);
990 goto driver_register_failed;
991 retval = usbdev_init();
993 goto usbdevice_init_failed;
994 retval = usbfs_init();
997 retval = usb_hub_init();
999 goto hub_init_failed;
1000 retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
1009 usbdevice_init_failed:
1010 usb_deregister(&usbfs_driver);
1011 driver_register_failed:
1012 usb_major_cleanup();
1016 bus_unregister(&usb_bus_type);
1024 static void __exit usb_exit(void)
1026 /* This will matter if shutdown/reboot does exitcalls. */
1030 usb_deregister_device_driver(&usb_generic_driver);
1031 usb_major_cleanup();
1033 usb_deregister(&usbfs_driver);
1037 bus_unregister(&usb_bus_type);
1040 subsys_initcall(usb_init);
1041 module_exit(usb_exit);
1044 * USB may be built into the kernel or be built as modules.
1045 * These symbols are exported for device (or host controller)
1046 * driver modules to use.
1049 EXPORT_SYMBOL(usb_disabled);
1051 EXPORT_SYMBOL_GPL(usb_get_intf);
1052 EXPORT_SYMBOL_GPL(usb_put_intf);
1054 EXPORT_SYMBOL(usb_put_dev);
1055 EXPORT_SYMBOL(usb_get_dev);
1056 EXPORT_SYMBOL(usb_hub_tt_clear_buffer);
1058 EXPORT_SYMBOL(usb_lock_device_for_reset);
1060 EXPORT_SYMBOL(usb_find_interface);
1061 EXPORT_SYMBOL(usb_ifnum_to_if);
1062 EXPORT_SYMBOL(usb_altnum_to_altsetting);
1064 EXPORT_SYMBOL(__usb_get_extra_descriptor);
1066 EXPORT_SYMBOL(usb_find_device);
1067 EXPORT_SYMBOL(usb_get_current_frame_number);
1069 EXPORT_SYMBOL_GPL(usb_endpoint_dir_in);
1070 EXPORT_SYMBOL_GPL(usb_endpoint_dir_out);
1071 EXPORT_SYMBOL_GPL(usb_endpoint_xfer_bulk);
1072 EXPORT_SYMBOL_GPL(usb_endpoint_xfer_int);
1073 EXPORT_SYMBOL_GPL(usb_endpoint_xfer_isoc);
1074 EXPORT_SYMBOL_GPL(usb_endpoint_is_bulk_in);
1075 EXPORT_SYMBOL_GPL(usb_endpoint_is_bulk_out);
1076 EXPORT_SYMBOL_GPL(usb_endpoint_is_int_in);
1077 EXPORT_SYMBOL_GPL(usb_endpoint_is_int_out);
1078 EXPORT_SYMBOL_GPL(usb_endpoint_is_isoc_in);
1079 EXPORT_SYMBOL_GPL(usb_endpoint_is_isoc_out);
1081 EXPORT_SYMBOL (usb_buffer_alloc);
1082 EXPORT_SYMBOL (usb_buffer_free);
1085 EXPORT_SYMBOL (usb_buffer_map);
1086 EXPORT_SYMBOL (usb_buffer_dmasync);
1087 EXPORT_SYMBOL (usb_buffer_unmap);
1090 EXPORT_SYMBOL (usb_buffer_map_sg);
1092 EXPORT_SYMBOL (usb_buffer_dmasync_sg);
1094 EXPORT_SYMBOL (usb_buffer_unmap_sg);
1096 MODULE_LICENSE("GPL");