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 bool nousb; /* Disable USB when built into kernel image */
52 #ifdef CONFIG_PM_RUNTIME
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);
212 struct each_dev_arg {
214 int (*fn)(struct usb_device *, void *);
217 static int __each_dev(struct device *dev, void *data)
219 struct each_dev_arg *arg = (struct each_dev_arg *)data;
221 /* There are struct usb_interface on the same bus, filter them out */
222 if (!is_usb_device(dev))
225 return arg->fn(container_of(dev, struct usb_device, dev), arg->data);
229 * usb_for_each_dev - iterate over all USB devices in the system
230 * @data: data pointer that will be handed to the callback function
231 * @fn: callback function to be called for each USB device
233 * Iterate over all USB devices and call @fn for each, passing it @data. If it
234 * returns anything other than 0, we break the iteration prematurely and return
237 int usb_for_each_dev(void *data, int (*fn)(struct usb_device *, void *))
239 struct each_dev_arg arg = {data, fn};
241 return bus_for_each_dev(&usb_bus_type, NULL, &arg, __each_dev);
243 EXPORT_SYMBOL_GPL(usb_for_each_dev);
246 * usb_release_dev - free a usb device structure when all users of it are finished.
247 * @dev: device that's been disconnected
249 * Will be called only by the device core when all users of this usb device are
252 static void usb_release_dev(struct device *dev)
254 struct usb_device *udev;
257 udev = to_usb_device(dev);
258 hcd = bus_to_hcd(udev->bus);
260 usb_destroy_configuration(udev);
261 usb_release_bos_descriptor(udev);
263 kfree(udev->product);
264 kfree(udev->manufacturer);
269 static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
271 struct usb_device *usb_dev;
273 usb_dev = to_usb_device(dev);
275 if (add_uevent_var(env, "BUSNUM=%03d", usb_dev->bus->busnum))
278 if (add_uevent_var(env, "DEVNUM=%03d", usb_dev->devnum))
286 /* USB device Power-Management thunks.
287 * There's no need to distinguish here between quiescing a USB device
288 * and powering it down; the generic_suspend() routine takes care of
289 * it by skipping the usb_port_suspend() call for a quiesce. And for
290 * USB interfaces there's no difference at all.
293 static int usb_dev_prepare(struct device *dev)
295 return 0; /* Implement eventually? */
298 static void usb_dev_complete(struct device *dev)
300 /* Currently used only for rebinding interfaces */
301 usb_resume_complete(dev);
304 static int usb_dev_suspend(struct device *dev)
306 return usb_suspend(dev, PMSG_SUSPEND);
309 static int usb_dev_resume(struct device *dev)
311 return usb_resume(dev, PMSG_RESUME);
314 static int usb_dev_freeze(struct device *dev)
316 return usb_suspend(dev, PMSG_FREEZE);
319 static int usb_dev_thaw(struct device *dev)
321 return usb_resume(dev, PMSG_THAW);
324 static int usb_dev_poweroff(struct device *dev)
326 return usb_suspend(dev, PMSG_HIBERNATE);
329 static int usb_dev_restore(struct device *dev)
331 return usb_resume(dev, PMSG_RESTORE);
334 static const struct dev_pm_ops usb_device_pm_ops = {
335 .prepare = usb_dev_prepare,
336 .complete = usb_dev_complete,
337 .suspend = usb_dev_suspend,
338 .resume = usb_dev_resume,
339 .freeze = usb_dev_freeze,
340 .thaw = usb_dev_thaw,
341 .poweroff = usb_dev_poweroff,
342 .restore = usb_dev_restore,
343 #ifdef CONFIG_PM_RUNTIME
344 .runtime_suspend = usb_runtime_suspend,
345 .runtime_resume = usb_runtime_resume,
346 .runtime_idle = usb_runtime_idle,
350 #endif /* CONFIG_PM */
353 static char *usb_devnode(struct device *dev,
354 umode_t *mode, kuid_t *uid, kgid_t *gid)
356 struct usb_device *usb_dev;
358 usb_dev = to_usb_device(dev);
359 return kasprintf(GFP_KERNEL, "bus/usb/%03d/%03d",
360 usb_dev->bus->busnum, usb_dev->devnum);
363 struct device_type usb_device_type = {
364 .name = "usb_device",
365 .release = usb_release_dev,
366 .uevent = usb_dev_uevent,
367 .devnode = usb_devnode,
369 .pm = &usb_device_pm_ops,
374 /* Returns 1 if @usb_bus is WUSB, 0 otherwise */
375 static unsigned usb_bus_is_wusb(struct usb_bus *bus)
377 struct usb_hcd *hcd = container_of(bus, struct usb_hcd, self);
378 return hcd->wireless;
383 * usb_alloc_dev - usb device constructor (usbcore-internal)
384 * @parent: hub to which device is connected; null to allocate a root hub
385 * @bus: bus used to access the device
386 * @port1: one-based index of port; ignored for root hubs
387 * Context: !in_interrupt()
389 * Only hub drivers (including virtual root hub drivers for host
390 * controllers) should ever call this.
392 * This call may not be used in a non-sleeping context.
394 struct usb_device *usb_alloc_dev(struct usb_device *parent,
395 struct usb_bus *bus, unsigned port1)
397 struct usb_device *dev;
398 struct usb_hcd *usb_hcd = bus_to_hcd(bus);
399 unsigned root_hub = 0;
401 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
405 if (!usb_get_hcd(usb_hcd)) {
409 /* Root hubs aren't true devices, so don't allocate HCD resources */
410 if (usb_hcd->driver->alloc_dev && parent &&
411 !usb_hcd->driver->alloc_dev(usb_hcd, dev)) {
412 usb_put_hcd(bus_to_hcd(bus));
417 device_initialize(&dev->dev);
418 dev->dev.bus = &usb_bus_type;
419 dev->dev.type = &usb_device_type;
420 dev->dev.groups = usb_device_groups;
421 dev->dev.dma_mask = bus->controller->dma_mask;
422 set_dev_node(&dev->dev, dev_to_node(bus->controller));
423 dev->state = USB_STATE_ATTACHED;
424 dev->lpm_disable_count = 1;
425 atomic_set(&dev->urbnum, 0);
427 INIT_LIST_HEAD(&dev->ep0.urb_list);
428 dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
429 dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
430 /* ep0 maxpacket comes later, from device descriptor */
431 usb_enable_endpoint(dev, &dev->ep0, false);
434 /* Save readable and stable topology id, distinguishing devices
435 * by location for diagnostics, tools, driver model, etc. The
436 * string is a path along hub ports, from the root. Each device's
437 * dev->devpath will be stable until USB is re-cabled, and hubs
438 * are often labeled with these port numbers. The name isn't
439 * as stable: bus->busnum changes easily from modprobe order,
440 * cardbus or pci hotplugging, and so on.
442 if (unlikely(!parent)) {
443 dev->devpath[0] = '0';
446 dev->dev.parent = bus->controller;
447 dev_set_name(&dev->dev, "usb%d", bus->busnum);
450 /* match any labeling on the hubs; it's one-based */
451 if (parent->devpath[0] == '0') {
452 snprintf(dev->devpath, sizeof dev->devpath,
454 /* Root ports are not counted in route string */
457 snprintf(dev->devpath, sizeof dev->devpath,
458 "%s.%d", parent->devpath, port1);
459 /* Route string assumes hubs have less than 16 ports */
461 dev->route = parent->route +
462 (port1 << ((parent->level - 1)*4));
464 dev->route = parent->route +
465 (15 << ((parent->level - 1)*4));
468 dev->dev.parent = &parent->dev;
469 dev_set_name(&dev->dev, "%d-%s", bus->busnum, dev->devpath);
471 /* hub driver sets up TT records */
474 dev->portnum = port1;
476 dev->parent = parent;
477 INIT_LIST_HEAD(&dev->filelist);
480 pm_runtime_set_autosuspend_delay(&dev->dev,
481 usb_autosuspend_delay * 1000);
482 dev->connect_time = jiffies;
483 dev->active_duration = -jiffies;
485 if (root_hub) /* Root hub always ok [and always wired] */
488 dev->authorized = usb_hcd->authorized_default;
489 dev->wusb = usb_bus_is_wusb(bus)? 1 : 0;
495 * usb_get_dev - increments the reference count of the usb device structure
496 * @dev: the device being referenced
498 * Each live reference to a device should be refcounted.
500 * Drivers for USB interfaces should normally record such references in
501 * their probe() methods, when they bind to an interface, and release
502 * them by calling usb_put_dev(), in their disconnect() methods.
504 * A pointer to the device with the incremented reference counter is returned.
506 struct usb_device *usb_get_dev(struct usb_device *dev)
509 get_device(&dev->dev);
512 EXPORT_SYMBOL_GPL(usb_get_dev);
515 * usb_put_dev - release a use of the usb device structure
516 * @dev: device that's been disconnected
518 * Must be called when a user of a device is finished with it. When the last
519 * user of the device calls this function, the memory of the device is freed.
521 void usb_put_dev(struct usb_device *dev)
524 put_device(&dev->dev);
526 EXPORT_SYMBOL_GPL(usb_put_dev);
529 * usb_get_intf - increments the reference count of the usb interface structure
530 * @intf: the interface being referenced
532 * Each live reference to a interface must be refcounted.
534 * Drivers for USB interfaces should normally record such references in
535 * their probe() methods, when they bind to an interface, and release
536 * them by calling usb_put_intf(), in their disconnect() methods.
538 * A pointer to the interface with the incremented reference counter is
541 struct usb_interface *usb_get_intf(struct usb_interface *intf)
544 get_device(&intf->dev);
547 EXPORT_SYMBOL_GPL(usb_get_intf);
550 * usb_put_intf - release a use of the usb interface structure
551 * @intf: interface that's been decremented
553 * Must be called when a user of an interface is finished with it. When the
554 * last user of the interface calls this function, the memory of the interface
557 void usb_put_intf(struct usb_interface *intf)
560 put_device(&intf->dev);
562 EXPORT_SYMBOL_GPL(usb_put_intf);
564 /* USB device locking
566 * USB devices and interfaces are locked using the semaphore in their
567 * embedded struct device. The hub driver guarantees that whenever a
568 * device is connected or disconnected, drivers are called with the
569 * USB device locked as well as their particular interface.
571 * Complications arise when several devices are to be locked at the same
572 * time. Only hub-aware drivers that are part of usbcore ever have to
573 * do this; nobody else needs to worry about it. The rule for locking
576 * When locking both a device and its parent, always lock the
581 * usb_lock_device_for_reset - cautiously acquire the lock for a usb device structure
582 * @udev: device that's being locked
583 * @iface: interface bound to the driver making the request (optional)
585 * Attempts to acquire the device lock, but fails if the device is
586 * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
587 * is neither BINDING nor BOUND. Rather than sleeping to wait for the
588 * lock, the routine polls repeatedly. This is to prevent deadlock with
589 * disconnect; in some drivers (such as usb-storage) the disconnect()
590 * or suspend() method will block waiting for a device reset to complete.
592 * Returns a negative error code for failure, otherwise 0.
594 int usb_lock_device_for_reset(struct usb_device *udev,
595 const struct usb_interface *iface)
597 unsigned long jiffies_expire = jiffies + HZ;
599 if (udev->state == USB_STATE_NOTATTACHED)
601 if (udev->state == USB_STATE_SUSPENDED)
602 return -EHOSTUNREACH;
603 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
604 iface->condition == USB_INTERFACE_UNBOUND))
607 while (!usb_trylock_device(udev)) {
609 /* If we can't acquire the lock after waiting one second,
610 * we're probably deadlocked */
611 if (time_after(jiffies, jiffies_expire))
615 if (udev->state == USB_STATE_NOTATTACHED)
617 if (udev->state == USB_STATE_SUSPENDED)
618 return -EHOSTUNREACH;
619 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
620 iface->condition == USB_INTERFACE_UNBOUND))
625 EXPORT_SYMBOL_GPL(usb_lock_device_for_reset);
628 * usb_get_current_frame_number - return current bus frame number
629 * @dev: the device whose bus is being queried
631 * Returns the current frame number for the USB host controller
632 * used with the given USB device. This can be used when scheduling
633 * isochronous requests.
635 * Note that different kinds of host controller have different
636 * "scheduling horizons". While one type might support scheduling only
637 * 32 frames into the future, others could support scheduling up to
638 * 1024 frames into the future.
640 int usb_get_current_frame_number(struct usb_device *dev)
642 return usb_hcd_get_frame_number(dev);
644 EXPORT_SYMBOL_GPL(usb_get_current_frame_number);
646 /*-------------------------------------------------------------------*/
648 * __usb_get_extra_descriptor() finds a descriptor of specific type in the
649 * extra field of the interface and endpoint descriptor structs.
652 int __usb_get_extra_descriptor(char *buffer, unsigned size,
653 unsigned char type, void **ptr)
655 struct usb_descriptor_header *header;
657 while (size >= sizeof(struct usb_descriptor_header)) {
658 header = (struct usb_descriptor_header *)buffer;
660 if (header->bLength < 2) {
662 "%s: bogus descriptor, type %d length %d\n",
664 header->bDescriptorType,
669 if (header->bDescriptorType == type) {
674 buffer += header->bLength;
675 size -= header->bLength;
679 EXPORT_SYMBOL_GPL(__usb_get_extra_descriptor);
682 * usb_alloc_coherent - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
683 * @dev: device the buffer will be used with
684 * @size: requested buffer size
685 * @mem_flags: affect whether allocation may block
686 * @dma: used to return DMA address of buffer
688 * Return value is either null (indicating no buffer could be allocated), or
689 * the cpu-space pointer to a buffer that may be used to perform DMA to the
690 * specified device. Such cpu-space buffers are returned along with the DMA
691 * address (through the pointer provided).
693 * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
694 * to avoid behaviors like using "DMA bounce buffers", or thrashing IOMMU
695 * hardware during URB completion/resubmit. The implementation varies between
696 * platforms, depending on details of how DMA will work to this device.
697 * Using these buffers also eliminates cacheline sharing problems on
698 * architectures where CPU caches are not DMA-coherent. On systems without
699 * bus-snooping caches, these buffers are uncached.
701 * When the buffer is no longer used, free it with usb_free_coherent().
703 void *usb_alloc_coherent(struct usb_device *dev, size_t size, gfp_t mem_flags,
706 if (!dev || !dev->bus)
708 return hcd_buffer_alloc(dev->bus, size, mem_flags, dma);
710 EXPORT_SYMBOL_GPL(usb_alloc_coherent);
713 * usb_free_coherent - free memory allocated with usb_alloc_coherent()
714 * @dev: device the buffer was used with
715 * @size: requested buffer size
716 * @addr: CPU address of buffer
717 * @dma: DMA address of buffer
719 * This reclaims an I/O buffer, letting it be reused. The memory must have
720 * been allocated using usb_alloc_coherent(), and the parameters must match
721 * those provided in that allocation request.
723 void usb_free_coherent(struct usb_device *dev, size_t size, void *addr,
726 if (!dev || !dev->bus)
730 hcd_buffer_free(dev->bus, size, addr, dma);
732 EXPORT_SYMBOL_GPL(usb_free_coherent);
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 is
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 /* FIXME generic api broken like pci, can't report errors */
768 /* if (urb->transfer_dma == DMA_ADDR_INVALID) return 0; */
770 urb->transfer_dma = ~0;
771 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
774 EXPORT_SYMBOL_GPL(usb_buffer_map);
777 /* XXX DISABLED, no users currently. If you wish to re-enable this
778 * XXX please determine whether the sync is to transfer ownership of
779 * XXX the buffer from device to cpu or vice verse, and thusly use the
780 * XXX appropriate _for_{cpu,device}() method. -DaveM
785 * usb_buffer_dmasync - synchronize DMA and CPU view of buffer(s)
786 * @urb: urb whose transfer_buffer/setup_packet will be synchronized
788 void usb_buffer_dmasync(struct urb *urb)
791 struct device *controller;
794 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
796 || !(bus = urb->dev->bus)
797 || !(controller = bus->controller))
800 if (controller->dma_mask) {
801 dma_sync_single_for_cpu(controller,
802 urb->transfer_dma, urb->transfer_buffer_length,
803 usb_pipein(urb->pipe)
804 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
805 if (usb_pipecontrol(urb->pipe))
806 dma_sync_single_for_cpu(controller,
808 sizeof(struct usb_ctrlrequest),
812 EXPORT_SYMBOL_GPL(usb_buffer_dmasync);
816 * usb_buffer_unmap - free DMA mapping(s) for an urb
817 * @urb: urb whose transfer_buffer will be unmapped
819 * Reverses the effect of usb_buffer_map().
822 void usb_buffer_unmap(struct urb *urb)
825 struct device *controller;
828 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
830 || !(bus = urb->dev->bus)
831 || !(controller = bus->controller))
834 if (controller->dma_mask) {
835 dma_unmap_single(controller,
836 urb->transfer_dma, urb->transfer_buffer_length,
837 usb_pipein(urb->pipe)
838 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
840 urb->transfer_flags &= ~URB_NO_TRANSFER_DMA_MAP;
842 EXPORT_SYMBOL_GPL(usb_buffer_unmap);
847 * usb_buffer_map_sg - create scatterlist DMA mapping(s) for an endpoint
848 * @dev: device to which the scatterlist will be mapped
849 * @is_in: mapping transfer direction
850 * @sg: the scatterlist to map
851 * @nents: the number of entries in the scatterlist
853 * Return value is either < 0 (indicating no buffers could be mapped), or
854 * the number of DMA mapping array entries in the scatterlist.
856 * The caller is responsible for placing the resulting DMA addresses from
857 * the scatterlist into URB transfer buffer pointers, and for setting the
858 * URB_NO_TRANSFER_DMA_MAP transfer flag in each of those URBs.
860 * Top I/O rates come from queuing URBs, instead of waiting for each one
861 * to complete before starting the next I/O. This is particularly easy
862 * to do with scatterlists. Just allocate and submit one URB for each DMA
863 * mapping entry returned, stopping on the first error or when all succeed.
864 * Better yet, use the usb_sg_*() calls, which do that (and more) for you.
866 * This call would normally be used when translating scatterlist requests,
867 * rather than usb_buffer_map(), since on some hardware (with IOMMUs) it
868 * may be able to coalesce mappings for improved I/O efficiency.
870 * Reverse the effect of this call with usb_buffer_unmap_sg().
872 int usb_buffer_map_sg(const struct usb_device *dev, int is_in,
873 struct scatterlist *sg, int nents)
876 struct device *controller;
880 || !(controller = bus->controller)
881 || !controller->dma_mask)
884 /* FIXME generic api broken like pci, can't report errors */
885 return dma_map_sg(controller, sg, nents,
886 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE) ? : -ENOMEM;
888 EXPORT_SYMBOL_GPL(usb_buffer_map_sg);
891 /* XXX DISABLED, no users currently. If you wish to re-enable this
892 * XXX please determine whether the sync is to transfer ownership of
893 * XXX the buffer from device to cpu or vice verse, and thusly use the
894 * XXX appropriate _for_{cpu,device}() method. -DaveM
899 * usb_buffer_dmasync_sg - synchronize DMA and CPU view of scatterlist buffer(s)
900 * @dev: device to which the scatterlist will be mapped
901 * @is_in: mapping transfer direction
902 * @sg: the scatterlist to synchronize
903 * @n_hw_ents: the positive return value from usb_buffer_map_sg
905 * Use this when you are re-using a scatterlist's data buffers for
906 * another USB request.
908 void usb_buffer_dmasync_sg(const struct usb_device *dev, int is_in,
909 struct scatterlist *sg, int n_hw_ents)
912 struct device *controller;
916 || !(controller = bus->controller)
917 || !controller->dma_mask)
920 dma_sync_sg_for_cpu(controller, sg, n_hw_ents,
921 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
923 EXPORT_SYMBOL_GPL(usb_buffer_dmasync_sg);
928 * usb_buffer_unmap_sg - free DMA mapping(s) for a scatterlist
929 * @dev: device to which the scatterlist will be mapped
930 * @is_in: mapping transfer direction
931 * @sg: the scatterlist to unmap
932 * @n_hw_ents: the positive return value from usb_buffer_map_sg
934 * Reverses the effect of usb_buffer_map_sg().
936 void usb_buffer_unmap_sg(const struct usb_device *dev, int is_in,
937 struct scatterlist *sg, int n_hw_ents)
940 struct device *controller;
944 || !(controller = bus->controller)
945 || !controller->dma_mask)
948 dma_unmap_sg(controller, sg, n_hw_ents,
949 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
951 EXPORT_SYMBOL_GPL(usb_buffer_unmap_sg);
954 /* To disable USB, kernel command line is 'nousb' not 'usbcore.nousb' */
956 module_param(nousb, bool, 0444);
958 core_param(nousb, nousb, bool, 0444);
962 * for external read access to <nousb>
964 int usb_disabled(void)
968 EXPORT_SYMBOL_GPL(usb_disabled);
971 * Notifications of device and interface registration
973 static int usb_bus_notify(struct notifier_block *nb, unsigned long action,
976 struct device *dev = data;
979 case BUS_NOTIFY_ADD_DEVICE:
980 if (dev->type == &usb_device_type)
981 (void) usb_create_sysfs_dev_files(to_usb_device(dev));
982 else if (dev->type == &usb_if_device_type)
983 usb_create_sysfs_intf_files(to_usb_interface(dev));
986 case BUS_NOTIFY_DEL_DEVICE:
987 if (dev->type == &usb_device_type)
988 usb_remove_sysfs_dev_files(to_usb_device(dev));
989 else if (dev->type == &usb_if_device_type)
990 usb_remove_sysfs_intf_files(to_usb_interface(dev));
996 static struct notifier_block usb_bus_nb = {
997 .notifier_call = usb_bus_notify,
1000 struct dentry *usb_debug_root;
1001 EXPORT_SYMBOL_GPL(usb_debug_root);
1003 static struct dentry *usb_debug_devices;
1005 static int usb_debugfs_init(void)
1007 usb_debug_root = debugfs_create_dir("usb", NULL);
1008 if (!usb_debug_root)
1011 usb_debug_devices = debugfs_create_file("devices", 0444,
1012 usb_debug_root, NULL,
1013 &usbfs_devices_fops);
1014 if (!usb_debug_devices) {
1015 debugfs_remove(usb_debug_root);
1016 usb_debug_root = NULL;
1023 static void usb_debugfs_cleanup(void)
1025 debugfs_remove(usb_debug_devices);
1026 debugfs_remove(usb_debug_root);
1032 static int __init usb_init(void)
1036 pr_info("%s: USB support disabled\n", usbcore_name);
1040 retval = usb_debugfs_init();
1044 usb_acpi_register();
1045 retval = bus_register(&usb_bus_type);
1047 goto bus_register_failed;
1048 retval = bus_register_notifier(&usb_bus_type, &usb_bus_nb);
1050 goto bus_notifier_failed;
1051 retval = usb_major_init();
1053 goto major_init_failed;
1054 retval = usb_register(&usbfs_driver);
1056 goto driver_register_failed;
1057 retval = usb_devio_init();
1059 goto usb_devio_init_failed;
1060 retval = usb_hub_init();
1062 goto hub_init_failed;
1063 retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
1069 usb_devio_cleanup();
1070 usb_devio_init_failed:
1071 usb_deregister(&usbfs_driver);
1072 driver_register_failed:
1073 usb_major_cleanup();
1075 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1076 bus_notifier_failed:
1077 bus_unregister(&usb_bus_type);
1078 bus_register_failed:
1079 usb_acpi_unregister();
1080 usb_debugfs_cleanup();
1088 static void __exit usb_exit(void)
1090 /* This will matter if shutdown/reboot does exitcalls. */
1094 usb_deregister_device_driver(&usb_generic_driver);
1095 usb_major_cleanup();
1096 usb_deregister(&usbfs_driver);
1097 usb_devio_cleanup();
1099 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1100 bus_unregister(&usb_bus_type);
1101 usb_acpi_unregister();
1102 usb_debugfs_cleanup();
1105 subsys_initcall(usb_init);
1106 module_exit(usb_exit);
1107 MODULE_LICENSE("GPL");