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/usb/hcd.h>
36 #include <linux/mutex.h>
37 #include <linux/workqueue.h>
38 #include <linux/debugfs.h>
41 #include <linux/scatterlist.h>
43 #include <linux/dma-mapping.h>
48 const char *usbcore_name = "usbcore";
50 static int nousb; /* Disable USB when built into kernel image */
52 #ifdef CONFIG_USB_SUSPEND
53 static int usb_autosuspend_delay = 2; /* Default delay value,
55 module_param_named(autosuspend, usb_autosuspend_delay, int, 0644);
56 MODULE_PARM_DESC(autosuspend, "default autosuspend delay");
59 #define usb_autosuspend_delay 0
64 * usb_find_alt_setting() - Given a configuration, find the alternate setting
65 * for the given interface.
66 * @config: the configuration to search (not necessarily the current config).
67 * @iface_num: interface number to search in
68 * @alt_num: alternate interface setting number to search for.
70 * Search the configuration's interface cache for the given alt setting.
72 struct usb_host_interface *usb_find_alt_setting(
73 struct usb_host_config *config,
74 unsigned int iface_num,
77 struct usb_interface_cache *intf_cache = NULL;
80 for (i = 0; i < config->desc.bNumInterfaces; i++) {
81 if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber
83 intf_cache = config->intf_cache[i];
89 for (i = 0; i < intf_cache->num_altsetting; i++)
90 if (intf_cache->altsetting[i].desc.bAlternateSetting == alt_num)
91 return &intf_cache->altsetting[i];
93 printk(KERN_DEBUG "Did not find alt setting %u for intf %u, "
94 "config %u\n", alt_num, iface_num,
95 config->desc.bConfigurationValue);
98 EXPORT_SYMBOL_GPL(usb_find_alt_setting);
101 * usb_ifnum_to_if - get the interface object with a given interface number
102 * @dev: the device whose current configuration is considered
103 * @ifnum: the desired interface
105 * This walks the device descriptor for the currently active configuration
106 * and returns a pointer to the interface with that particular interface
109 * Note that configuration descriptors are not required to assign interface
110 * numbers sequentially, so that it would be incorrect to assume that
111 * the first interface in that descriptor corresponds to interface zero.
112 * This routine helps device drivers avoid such mistakes.
113 * However, you should make sure that you do the right thing with any
114 * alternate settings available for this interfaces.
116 * Don't call this function unless you are bound to one of the interfaces
117 * on this device or you have locked the device!
119 struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
122 struct usb_host_config *config = dev->actconfig;
127 for (i = 0; i < config->desc.bNumInterfaces; i++)
128 if (config->interface[i]->altsetting[0]
129 .desc.bInterfaceNumber == ifnum)
130 return config->interface[i];
134 EXPORT_SYMBOL_GPL(usb_ifnum_to_if);
137 * usb_altnum_to_altsetting - get the altsetting structure with a given alternate setting number.
138 * @intf: the interface containing the altsetting in question
139 * @altnum: the desired alternate setting number
141 * This searches the altsetting array of the specified interface for
142 * an entry with the correct bAlternateSetting value and returns a pointer
143 * to that entry, or null.
145 * Note that altsettings need not be stored sequentially by number, so
146 * it would be incorrect to assume that the first altsetting entry in
147 * the array corresponds to altsetting zero. This routine helps device
148 * drivers avoid such mistakes.
150 * Don't call this function unless you are bound to the intf interface
151 * or you have locked the device!
153 struct usb_host_interface *usb_altnum_to_altsetting(
154 const struct usb_interface *intf,
159 for (i = 0; i < intf->num_altsetting; i++) {
160 if (intf->altsetting[i].desc.bAlternateSetting == altnum)
161 return &intf->altsetting[i];
165 EXPORT_SYMBOL_GPL(usb_altnum_to_altsetting);
167 struct find_interface_arg {
169 struct device_driver *drv;
172 static int __find_interface(struct device *dev, void *data)
174 struct find_interface_arg *arg = data;
175 struct usb_interface *intf;
177 if (!is_usb_interface(dev))
180 if (dev->driver != arg->drv)
182 intf = to_usb_interface(dev);
183 return intf->minor == arg->minor;
187 * usb_find_interface - find usb_interface pointer for driver and device
188 * @drv: the driver whose current configuration is considered
189 * @minor: the minor number of the desired device
191 * This walks the bus device list and returns a pointer to the interface
192 * with the matching minor and driver. Note, this only works for devices
193 * that share the USB major number.
195 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
197 struct find_interface_arg argb;
201 argb.drv = &drv->drvwrap.driver;
203 dev = bus_find_device(&usb_bus_type, NULL, &argb, __find_interface);
205 /* Drop reference count from bus_find_device */
208 return dev ? to_usb_interface(dev) : NULL;
210 EXPORT_SYMBOL_GPL(usb_find_interface);
213 * usb_release_dev - free a usb device structure when all users of it are finished.
214 * @dev: device that's been disconnected
216 * Will be called only by the device core when all users of this usb device are
219 static void usb_release_dev(struct device *dev)
221 struct usb_device *udev;
224 udev = to_usb_device(dev);
225 hcd = bus_to_hcd(udev->bus);
227 usb_destroy_configuration(udev);
229 kfree(udev->product);
230 kfree(udev->manufacturer);
235 #ifdef CONFIG_HOTPLUG
236 static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
238 struct usb_device *usb_dev;
240 usb_dev = to_usb_device(dev);
242 if (add_uevent_var(env, "BUSNUM=%03d", usb_dev->bus->busnum))
245 if (add_uevent_var(env, "DEVNUM=%03d", usb_dev->devnum))
253 static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
257 #endif /* CONFIG_HOTPLUG */
261 /* USB device Power-Management thunks.
262 * There's no need to distinguish here between quiescing a USB device
263 * and powering it down; the generic_suspend() routine takes care of
264 * it by skipping the usb_port_suspend() call for a quiesce. And for
265 * USB interfaces there's no difference at all.
268 static int usb_dev_prepare(struct device *dev)
270 return 0; /* Implement eventually? */
273 static void usb_dev_complete(struct device *dev)
275 /* Currently used only for rebinding interfaces */
276 usb_resume(dev, PMSG_ON); /* FIXME: change to PMSG_COMPLETE */
279 static int usb_dev_suspend(struct device *dev)
281 return usb_suspend(dev, PMSG_SUSPEND);
284 static int usb_dev_resume(struct device *dev)
286 return usb_resume(dev, PMSG_RESUME);
289 static int usb_dev_freeze(struct device *dev)
291 return usb_suspend(dev, PMSG_FREEZE);
294 static int usb_dev_thaw(struct device *dev)
296 return usb_resume(dev, PMSG_THAW);
299 static int usb_dev_poweroff(struct device *dev)
301 return usb_suspend(dev, PMSG_HIBERNATE);
304 static int usb_dev_restore(struct device *dev)
306 return usb_resume(dev, PMSG_RESTORE);
309 static const struct dev_pm_ops usb_device_pm_ops = {
310 .prepare = usb_dev_prepare,
311 .complete = usb_dev_complete,
312 .suspend = usb_dev_suspend,
313 .resume = usb_dev_resume,
314 .freeze = usb_dev_freeze,
315 .thaw = usb_dev_thaw,
316 .poweroff = usb_dev_poweroff,
317 .restore = usb_dev_restore,
322 #define usb_device_pm_ops (*(struct dev_pm_ops *) NULL)
324 #endif /* CONFIG_PM */
327 static char *usb_devnode(struct device *dev, mode_t *mode)
329 struct usb_device *usb_dev;
331 usb_dev = to_usb_device(dev);
332 return kasprintf(GFP_KERNEL, "bus/usb/%03d/%03d",
333 usb_dev->bus->busnum, usb_dev->devnum);
336 struct device_type usb_device_type = {
337 .name = "usb_device",
338 .release = usb_release_dev,
339 .uevent = usb_dev_uevent,
340 .devnode = usb_devnode,
341 .pm = &usb_device_pm_ops,
345 /* Returns 1 if @usb_bus is WUSB, 0 otherwise */
346 static unsigned usb_bus_is_wusb(struct usb_bus *bus)
348 struct usb_hcd *hcd = container_of(bus, struct usb_hcd, self);
349 return hcd->wireless;
354 * usb_alloc_dev - usb device constructor (usbcore-internal)
355 * @parent: hub to which device is connected; null to allocate a root hub
356 * @bus: bus used to access the device
357 * @port1: one-based index of port; ignored for root hubs
358 * Context: !in_interrupt()
360 * Only hub drivers (including virtual root hub drivers for host
361 * controllers) should ever call this.
363 * This call may not be used in a non-sleeping context.
365 struct usb_device *usb_alloc_dev(struct usb_device *parent,
366 struct usb_bus *bus, unsigned port1)
368 struct usb_device *dev;
369 struct usb_hcd *usb_hcd = container_of(bus, struct usb_hcd, self);
370 unsigned root_hub = 0;
372 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
376 if (!usb_get_hcd(bus_to_hcd(bus))) {
380 /* Root hubs aren't true devices, so don't allocate HCD resources */
381 if (usb_hcd->driver->alloc_dev && parent &&
382 !usb_hcd->driver->alloc_dev(usb_hcd, dev)) {
383 usb_put_hcd(bus_to_hcd(bus));
388 device_initialize(&dev->dev);
389 dev->dev.bus = &usb_bus_type;
390 dev->dev.type = &usb_device_type;
391 dev->dev.groups = usb_device_groups;
392 dev->dev.dma_mask = bus->controller->dma_mask;
393 set_dev_node(&dev->dev, dev_to_node(bus->controller));
394 dev->state = USB_STATE_ATTACHED;
395 atomic_set(&dev->urbnum, 0);
397 INIT_LIST_HEAD(&dev->ep0.urb_list);
398 dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
399 dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
400 /* ep0 maxpacket comes later, from device descriptor */
401 usb_enable_endpoint(dev, &dev->ep0, false);
404 /* Save readable and stable topology id, distinguishing devices
405 * by location for diagnostics, tools, driver model, etc. The
406 * string is a path along hub ports, from the root. Each device's
407 * dev->devpath will be stable until USB is re-cabled, and hubs
408 * are often labeled with these port numbers. The name isn't
409 * as stable: bus->busnum changes easily from modprobe order,
410 * cardbus or pci hotplugging, and so on.
412 if (unlikely(!parent)) {
413 dev->devpath[0] = '0';
416 dev->dev.parent = bus->controller;
417 dev_set_name(&dev->dev, "usb%d", bus->busnum);
420 /* match any labeling on the hubs; it's one-based */
421 if (parent->devpath[0] == '0') {
422 snprintf(dev->devpath, sizeof dev->devpath,
424 /* Root ports are not counted in route string */
427 snprintf(dev->devpath, sizeof dev->devpath,
428 "%s.%d", parent->devpath, port1);
429 /* Route string assumes hubs have less than 16 ports */
431 dev->route = parent->route +
432 (port1 << ((parent->level - 1)*4));
434 dev->route = parent->route +
435 (15 << ((parent->level - 1)*4));
438 dev->dev.parent = &parent->dev;
439 dev_set_name(&dev->dev, "%d-%s", bus->busnum, dev->devpath);
441 /* hub driver sets up TT records */
444 dev->portnum = port1;
446 dev->parent = parent;
447 INIT_LIST_HEAD(&dev->filelist);
450 dev->autosuspend_delay = usb_autosuspend_delay * HZ;
451 dev->connect_time = jiffies;
452 dev->active_duration = -jiffies;
454 if (root_hub) /* Root hub always ok [and always wired] */
457 dev->authorized = usb_hcd->authorized_default;
458 dev->wusb = usb_bus_is_wusb(bus)? 1 : 0;
464 * usb_get_dev - increments the reference count of the usb device structure
465 * @dev: the device being referenced
467 * Each live reference to a device should be refcounted.
469 * Drivers for USB interfaces should normally record such references in
470 * their probe() methods, when they bind to an interface, and release
471 * them by calling usb_put_dev(), in their disconnect() methods.
473 * A pointer to the device with the incremented reference counter is returned.
475 struct usb_device *usb_get_dev(struct usb_device *dev)
478 get_device(&dev->dev);
481 EXPORT_SYMBOL_GPL(usb_get_dev);
484 * usb_put_dev - release a use of the usb device structure
485 * @dev: device that's been disconnected
487 * Must be called when a user of a device is finished with it. When the last
488 * user of the device calls this function, the memory of the device is freed.
490 void usb_put_dev(struct usb_device *dev)
493 put_device(&dev->dev);
495 EXPORT_SYMBOL_GPL(usb_put_dev);
498 * usb_get_intf - increments the reference count of the usb interface structure
499 * @intf: the interface being referenced
501 * Each live reference to a interface must be refcounted.
503 * Drivers for USB interfaces should normally record such references in
504 * their probe() methods, when they bind to an interface, and release
505 * them by calling usb_put_intf(), in their disconnect() methods.
507 * A pointer to the interface with the incremented reference counter is
510 struct usb_interface *usb_get_intf(struct usb_interface *intf)
513 get_device(&intf->dev);
516 EXPORT_SYMBOL_GPL(usb_get_intf);
519 * usb_put_intf - release a use of the usb interface structure
520 * @intf: interface that's been decremented
522 * Must be called when a user of an interface is finished with it. When the
523 * last user of the interface calls this function, the memory of the interface
526 void usb_put_intf(struct usb_interface *intf)
529 put_device(&intf->dev);
531 EXPORT_SYMBOL_GPL(usb_put_intf);
533 /* USB device locking
535 * USB devices and interfaces are locked using the semaphore in their
536 * embedded struct device. The hub driver guarantees that whenever a
537 * device is connected or disconnected, drivers are called with the
538 * USB device locked as well as their particular interface.
540 * Complications arise when several devices are to be locked at the same
541 * time. Only hub-aware drivers that are part of usbcore ever have to
542 * do this; nobody else needs to worry about it. The rule for locking
545 * When locking both a device and its parent, always lock the
550 * usb_lock_device_for_reset - cautiously acquire the lock for a usb device structure
551 * @udev: device that's being locked
552 * @iface: interface bound to the driver making the request (optional)
554 * Attempts to acquire the device lock, but fails if the device is
555 * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
556 * is neither BINDING nor BOUND. Rather than sleeping to wait for the
557 * lock, the routine polls repeatedly. This is to prevent deadlock with
558 * disconnect; in some drivers (such as usb-storage) the disconnect()
559 * or suspend() method will block waiting for a device reset to complete.
561 * Returns a negative error code for failure, otherwise 0.
563 int usb_lock_device_for_reset(struct usb_device *udev,
564 const struct usb_interface *iface)
566 unsigned long jiffies_expire = jiffies + HZ;
568 if (udev->state == USB_STATE_NOTATTACHED)
570 if (udev->state == USB_STATE_SUSPENDED)
571 return -EHOSTUNREACH;
572 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
573 iface->condition == USB_INTERFACE_UNBOUND))
576 while (usb_trylock_device(udev) != 0) {
578 /* If we can't acquire the lock after waiting one second,
579 * we're probably deadlocked */
580 if (time_after(jiffies, jiffies_expire))
584 if (udev->state == USB_STATE_NOTATTACHED)
586 if (udev->state == USB_STATE_SUSPENDED)
587 return -EHOSTUNREACH;
588 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
589 iface->condition == USB_INTERFACE_UNBOUND))
594 EXPORT_SYMBOL_GPL(usb_lock_device_for_reset);
596 static struct usb_device *match_device(struct usb_device *dev,
597 u16 vendor_id, u16 product_id)
599 struct usb_device *ret_dev = NULL;
602 dev_dbg(&dev->dev, "check for vendor %04x, product %04x ...\n",
603 le16_to_cpu(dev->descriptor.idVendor),
604 le16_to_cpu(dev->descriptor.idProduct));
606 /* see if this device matches */
607 if ((vendor_id == le16_to_cpu(dev->descriptor.idVendor)) &&
608 (product_id == le16_to_cpu(dev->descriptor.idProduct))) {
609 dev_dbg(&dev->dev, "matched this device!\n");
610 ret_dev = usb_get_dev(dev);
614 /* look through all of the children of this device */
615 for (child = 0; child < dev->maxchild; ++child) {
616 if (dev->children[child]) {
617 usb_lock_device(dev->children[child]);
618 ret_dev = match_device(dev->children[child],
619 vendor_id, product_id);
620 usb_unlock_device(dev->children[child]);
630 * usb_get_current_frame_number - return current bus frame number
631 * @dev: the device whose bus is being queried
633 * Returns the current frame number for the USB host controller
634 * used with the given USB device. This can be used when scheduling
635 * isochronous requests.
637 * Note that different kinds of host controller have different
638 * "scheduling horizons". While one type might support scheduling only
639 * 32 frames into the future, others could support scheduling up to
640 * 1024 frames into the future.
642 int usb_get_current_frame_number(struct usb_device *dev)
644 return usb_hcd_get_frame_number(dev);
646 EXPORT_SYMBOL_GPL(usb_get_current_frame_number);
648 /*-------------------------------------------------------------------*/
650 * __usb_get_extra_descriptor() finds a descriptor of specific type in the
651 * extra field of the interface and endpoint descriptor structs.
654 int __usb_get_extra_descriptor(char *buffer, unsigned size,
655 unsigned char type, void **ptr)
657 struct usb_descriptor_header *header;
659 while (size >= sizeof(struct usb_descriptor_header)) {
660 header = (struct usb_descriptor_header *)buffer;
662 if (header->bLength < 2) {
664 "%s: bogus descriptor, type %d length %d\n",
666 header->bDescriptorType,
671 if (header->bDescriptorType == type) {
676 buffer += header->bLength;
677 size -= header->bLength;
681 EXPORT_SYMBOL_GPL(__usb_get_extra_descriptor);
684 * usb_alloc_coherent - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
685 * @dev: device the buffer will be used with
686 * @size: requested buffer size
687 * @mem_flags: affect whether allocation may block
688 * @dma: used to return DMA address of buffer
690 * Return value is either null (indicating no buffer could be allocated), or
691 * the cpu-space pointer to a buffer that may be used to perform DMA to the
692 * specified device. Such cpu-space buffers are returned along with the DMA
693 * address (through the pointer provided).
695 * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
696 * to avoid behaviors like using "DMA bounce buffers", or thrashing IOMMU
697 * hardware during URB completion/resubmit. The implementation varies between
698 * platforms, depending on details of how DMA will work to this device.
699 * Using these buffers also eliminates cacheline sharing problems on
700 * architectures where CPU caches are not DMA-coherent. On systems without
701 * bus-snooping caches, these buffers are uncached.
703 * When the buffer is no longer used, free it with usb_free_coherent().
705 void *usb_alloc_coherent(struct usb_device *dev, size_t size, gfp_t mem_flags,
708 if (!dev || !dev->bus)
710 return hcd_buffer_alloc(dev->bus, size, mem_flags, dma);
712 EXPORT_SYMBOL_GPL(usb_alloc_coherent);
715 * usb_free_coherent - free memory allocated with usb_alloc_coherent()
716 * @dev: device the buffer was used with
717 * @size: requested buffer size
718 * @addr: CPU address of buffer
719 * @dma: DMA address of buffer
721 * This reclaims an I/O buffer, letting it be reused. The memory must have
722 * been allocated using usb_alloc_coherent(), and the parameters must match
723 * those provided in that allocation request.
725 void usb_free_coherent(struct usb_device *dev, size_t size, void *addr,
728 if (!dev || !dev->bus)
732 hcd_buffer_free(dev->bus, size, addr, dma);
734 EXPORT_SYMBOL_GPL(usb_free_coherent);
737 * usb_buffer_map - create DMA mapping(s) for an urb
738 * @urb: urb whose transfer_buffer/setup_packet will be mapped
740 * Return value is either null (indicating no buffer could be mapped), or
741 * the parameter. URB_NO_TRANSFER_DMA_MAP is
742 * added to urb->transfer_flags if the operation succeeds. If the device
743 * is connected to this system through a non-DMA controller, this operation
746 * This call would normally be used for an urb which is reused, perhaps
747 * as the target of a large periodic transfer, with usb_buffer_dmasync()
748 * calls to synchronize memory and dma state.
750 * Reverse the effect of this call with usb_buffer_unmap().
753 struct urb *usb_buffer_map(struct urb *urb)
756 struct device *controller;
760 || !(bus = urb->dev->bus)
761 || !(controller = bus->controller))
764 if (controller->dma_mask) {
765 urb->transfer_dma = dma_map_single(controller,
766 urb->transfer_buffer, urb->transfer_buffer_length,
767 usb_pipein(urb->pipe)
768 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
769 /* FIXME generic api broken like pci, can't report errors */
770 /* if (urb->transfer_dma == DMA_ADDR_INVALID) return 0; */
772 urb->transfer_dma = ~0;
773 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
776 EXPORT_SYMBOL_GPL(usb_buffer_map);
779 /* XXX DISABLED, no users currently. If you wish to re-enable this
780 * XXX please determine whether the sync is to transfer ownership of
781 * XXX the buffer from device to cpu or vice verse, and thusly use the
782 * XXX appropriate _for_{cpu,device}() method. -DaveM
787 * usb_buffer_dmasync - synchronize DMA and CPU view of buffer(s)
788 * @urb: urb whose transfer_buffer/setup_packet will be synchronized
790 void usb_buffer_dmasync(struct urb *urb)
793 struct device *controller;
796 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
798 || !(bus = urb->dev->bus)
799 || !(controller = bus->controller))
802 if (controller->dma_mask) {
803 dma_sync_single_for_cpu(controller,
804 urb->transfer_dma, urb->transfer_buffer_length,
805 usb_pipein(urb->pipe)
806 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
807 if (usb_pipecontrol(urb->pipe))
808 dma_sync_single_for_cpu(controller,
810 sizeof(struct usb_ctrlrequest),
814 EXPORT_SYMBOL_GPL(usb_buffer_dmasync);
818 * usb_buffer_unmap - free DMA mapping(s) for an urb
819 * @urb: urb whose transfer_buffer will be unmapped
821 * Reverses the effect of usb_buffer_map().
824 void usb_buffer_unmap(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_unmap_single(controller,
838 urb->transfer_dma, urb->transfer_buffer_length,
839 usb_pipein(urb->pipe)
840 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
842 urb->transfer_flags &= ~URB_NO_TRANSFER_DMA_MAP;
844 EXPORT_SYMBOL_GPL(usb_buffer_unmap);
849 * usb_buffer_map_sg - create scatterlist DMA mapping(s) for an endpoint
850 * @dev: device to which the scatterlist will be mapped
851 * @is_in: mapping transfer direction
852 * @sg: the scatterlist to map
853 * @nents: the number of entries in the scatterlist
855 * Return value is either < 0 (indicating no buffers could be mapped), or
856 * the number of DMA mapping array entries in the scatterlist.
858 * The caller is responsible for placing the resulting DMA addresses from
859 * the scatterlist into URB transfer buffer pointers, and for setting the
860 * URB_NO_TRANSFER_DMA_MAP transfer flag in each of those URBs.
862 * Top I/O rates come from queuing URBs, instead of waiting for each one
863 * to complete before starting the next I/O. This is particularly easy
864 * to do with scatterlists. Just allocate and submit one URB for each DMA
865 * mapping entry returned, stopping on the first error or when all succeed.
866 * Better yet, use the usb_sg_*() calls, which do that (and more) for you.
868 * This call would normally be used when translating scatterlist requests,
869 * rather than usb_buffer_map(), since on some hardware (with IOMMUs) it
870 * may be able to coalesce mappings for improved I/O efficiency.
872 * Reverse the effect of this call with usb_buffer_unmap_sg().
874 int usb_buffer_map_sg(const struct usb_device *dev, int is_in,
875 struct scatterlist *sg, int nents)
878 struct device *controller;
882 || !(controller = bus->controller)
883 || !controller->dma_mask)
886 /* FIXME generic api broken like pci, can't report errors */
887 return dma_map_sg(controller, sg, nents,
888 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE) ? : -ENOMEM;
890 EXPORT_SYMBOL_GPL(usb_buffer_map_sg);
893 /* XXX DISABLED, no users currently. If you wish to re-enable this
894 * XXX please determine whether the sync is to transfer ownership of
895 * XXX the buffer from device to cpu or vice verse, and thusly use the
896 * XXX appropriate _for_{cpu,device}() method. -DaveM
901 * usb_buffer_dmasync_sg - synchronize DMA and CPU view of scatterlist buffer(s)
902 * @dev: device to which the scatterlist will be mapped
903 * @is_in: mapping transfer direction
904 * @sg: the scatterlist to synchronize
905 * @n_hw_ents: the positive return value from usb_buffer_map_sg
907 * Use this when you are re-using a scatterlist's data buffers for
908 * another USB request.
910 void usb_buffer_dmasync_sg(const struct usb_device *dev, int is_in,
911 struct scatterlist *sg, int n_hw_ents)
914 struct device *controller;
918 || !(controller = bus->controller)
919 || !controller->dma_mask)
922 dma_sync_sg_for_cpu(controller, sg, n_hw_ents,
923 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
925 EXPORT_SYMBOL_GPL(usb_buffer_dmasync_sg);
930 * usb_buffer_unmap_sg - free DMA mapping(s) for a scatterlist
931 * @dev: device to which the scatterlist will be mapped
932 * @is_in: mapping transfer direction
933 * @sg: the scatterlist to unmap
934 * @n_hw_ents: the positive return value from usb_buffer_map_sg
936 * Reverses the effect of usb_buffer_map_sg().
938 void usb_buffer_unmap_sg(const struct usb_device *dev, int is_in,
939 struct scatterlist *sg, int n_hw_ents)
942 struct device *controller;
946 || !(controller = bus->controller)
947 || !controller->dma_mask)
950 dma_unmap_sg(controller, sg, n_hw_ents,
951 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
953 EXPORT_SYMBOL_GPL(usb_buffer_unmap_sg);
956 /* To disable USB, kernel command line is 'nousb' not 'usbcore.nousb' */
958 module_param(nousb, bool, 0444);
960 core_param(nousb, nousb, bool, 0444);
964 * for external read access to <nousb>
966 int usb_disabled(void)
970 EXPORT_SYMBOL_GPL(usb_disabled);
973 * Notifications of device and interface registration
975 static int usb_bus_notify(struct notifier_block *nb, unsigned long action,
978 struct device *dev = data;
981 case BUS_NOTIFY_ADD_DEVICE:
982 if (dev->type == &usb_device_type)
983 (void) usb_create_sysfs_dev_files(to_usb_device(dev));
984 else if (dev->type == &usb_if_device_type)
985 (void) usb_create_sysfs_intf_files(
986 to_usb_interface(dev));
989 case BUS_NOTIFY_DEL_DEVICE:
990 if (dev->type == &usb_device_type)
991 usb_remove_sysfs_dev_files(to_usb_device(dev));
992 else if (dev->type == &usb_if_device_type)
993 usb_remove_sysfs_intf_files(to_usb_interface(dev));
999 static struct notifier_block usb_bus_nb = {
1000 .notifier_call = usb_bus_notify,
1003 struct dentry *usb_debug_root;
1004 EXPORT_SYMBOL_GPL(usb_debug_root);
1006 static struct dentry *usb_debug_devices;
1008 static int usb_debugfs_init(void)
1010 usb_debug_root = debugfs_create_dir("usb", NULL);
1011 if (!usb_debug_root)
1014 usb_debug_devices = debugfs_create_file("devices", 0444,
1015 usb_debug_root, NULL,
1016 &usbfs_devices_fops);
1017 if (!usb_debug_devices) {
1018 debugfs_remove(usb_debug_root);
1019 usb_debug_root = NULL;
1026 static void usb_debugfs_cleanup(void)
1028 debugfs_remove(usb_debug_devices);
1029 debugfs_remove(usb_debug_root);
1035 static int __init usb_init(void)
1039 pr_info("%s: USB support disabled\n", usbcore_name);
1043 retval = usb_debugfs_init();
1047 retval = bus_register(&usb_bus_type);
1049 goto bus_register_failed;
1050 retval = bus_register_notifier(&usb_bus_type, &usb_bus_nb);
1052 goto bus_notifier_failed;
1053 retval = usb_major_init();
1055 goto major_init_failed;
1056 retval = usb_register(&usbfs_driver);
1058 goto driver_register_failed;
1059 retval = usb_devio_init();
1061 goto usb_devio_init_failed;
1062 retval = usbfs_init();
1064 goto fs_init_failed;
1065 retval = usb_hub_init();
1067 goto hub_init_failed;
1068 retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
1076 usb_devio_cleanup();
1077 usb_devio_init_failed:
1078 usb_deregister(&usbfs_driver);
1079 driver_register_failed:
1080 usb_major_cleanup();
1082 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1083 bus_notifier_failed:
1084 bus_unregister(&usb_bus_type);
1085 bus_register_failed:
1086 usb_debugfs_cleanup();
1094 static void __exit usb_exit(void)
1096 /* This will matter if shutdown/reboot does exitcalls. */
1100 usb_deregister_device_driver(&usb_generic_driver);
1101 usb_major_cleanup();
1103 usb_deregister(&usbfs_driver);
1104 usb_devio_cleanup();
1106 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1107 bus_unregister(&usb_bus_type);
1108 usb_debugfs_cleanup();
1111 subsys_initcall(usb_init);
1112 module_exit(usb_exit);
1113 MODULE_LICENSE("GPL");