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 * Released under the GPLv2 only.
16 * SPDX-License-Identifier: GPL-2.0
18 * NOTE! This is not actually a driver at all, rather this is
19 * just a collection of helper routines that implement the
20 * generic USB things that the real drivers can use..
22 * Think of this as a "USB library" rather than anything else.
23 * It should be considered a slave, with no callbacks. Callbacks
27 #include <linux/module.h>
28 #include <linux/moduleparam.h>
29 #include <linux/string.h>
30 #include <linux/bitops.h>
31 #include <linux/slab.h>
32 #include <linux/interrupt.h> /* for in_interrupt() */
33 #include <linux/kmod.h>
34 #include <linux/init.h>
35 #include <linux/spinlock.h>
36 #include <linux/errno.h>
37 #include <linux/usb.h>
38 #include <linux/usb/hcd.h>
39 #include <linux/mutex.h>
40 #include <linux/workqueue.h>
41 #include <linux/debugfs.h>
42 #include <linux/usb/of.h>
45 #include <linux/scatterlist.h>
47 #include <linux/dma-mapping.h>
52 const char *usbcore_name = "usbcore";
54 static bool nousb; /* Disable USB when built into kernel image */
56 module_param(nousb, bool, 0444);
59 * for external read access to <nousb>
61 int usb_disabled(void)
65 EXPORT_SYMBOL_GPL(usb_disabled);
68 static int usb_autosuspend_delay = 2; /* Default delay value,
70 module_param_named(autosuspend, usb_autosuspend_delay, int, 0644);
71 MODULE_PARM_DESC(autosuspend, "default autosuspend delay");
74 #define usb_autosuspend_delay 0
77 static bool match_endpoint(struct usb_endpoint_descriptor *epd,
78 struct usb_endpoint_descriptor **bulk_in,
79 struct usb_endpoint_descriptor **bulk_out,
80 struct usb_endpoint_descriptor **int_in,
81 struct usb_endpoint_descriptor **int_out)
83 switch (usb_endpoint_type(epd)) {
84 case USB_ENDPOINT_XFER_BULK:
85 if (usb_endpoint_dir_in(epd)) {
86 if (bulk_in && !*bulk_in) {
91 if (bulk_out && !*bulk_out) {
98 case USB_ENDPOINT_XFER_INT:
99 if (usb_endpoint_dir_in(epd)) {
100 if (int_in && !*int_in) {
105 if (int_out && !*int_out) {
116 return (!bulk_in || *bulk_in) && (!bulk_out || *bulk_out) &&
117 (!int_in || *int_in) && (!int_out || *int_out);
121 * usb_find_common_endpoints() -- look up common endpoint descriptors
122 * @alt: alternate setting to search
123 * @bulk_in: pointer to descriptor pointer, or NULL
124 * @bulk_out: pointer to descriptor pointer, or NULL
125 * @int_in: pointer to descriptor pointer, or NULL
126 * @int_out: pointer to descriptor pointer, or NULL
128 * Search the alternate setting's endpoint descriptors for the first bulk-in,
129 * bulk-out, interrupt-in and interrupt-out endpoints and return them in the
130 * provided pointers (unless they are NULL).
132 * If a requested endpoint is not found, the corresponding pointer is set to
135 * Return: Zero if all requested descriptors were found, or -ENXIO otherwise.
137 int usb_find_common_endpoints(struct usb_host_interface *alt,
138 struct usb_endpoint_descriptor **bulk_in,
139 struct usb_endpoint_descriptor **bulk_out,
140 struct usb_endpoint_descriptor **int_in,
141 struct usb_endpoint_descriptor **int_out)
143 struct usb_endpoint_descriptor *epd;
155 for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
156 epd = &alt->endpoint[i].desc;
158 if (match_endpoint(epd, bulk_in, bulk_out, int_in, int_out))
164 EXPORT_SYMBOL_GPL(usb_find_common_endpoints);
167 * usb_find_common_endpoints_reverse() -- look up common endpoint descriptors
168 * @alt: alternate setting to search
169 * @bulk_in: pointer to descriptor pointer, or NULL
170 * @bulk_out: pointer to descriptor pointer, or NULL
171 * @int_in: pointer to descriptor pointer, or NULL
172 * @int_out: pointer to descriptor pointer, or NULL
174 * Search the alternate setting's endpoint descriptors for the last bulk-in,
175 * bulk-out, interrupt-in and interrupt-out endpoints and return them in the
176 * provided pointers (unless they are NULL).
178 * If a requested endpoint is not found, the corresponding pointer is set to
181 * Return: Zero if all requested descriptors were found, or -ENXIO otherwise.
183 int usb_find_common_endpoints_reverse(struct usb_host_interface *alt,
184 struct usb_endpoint_descriptor **bulk_in,
185 struct usb_endpoint_descriptor **bulk_out,
186 struct usb_endpoint_descriptor **int_in,
187 struct usb_endpoint_descriptor **int_out)
189 struct usb_endpoint_descriptor *epd;
201 for (i = alt->desc.bNumEndpoints - 1; i >= 0; --i) {
202 epd = &alt->endpoint[i].desc;
204 if (match_endpoint(epd, bulk_in, bulk_out, int_in, int_out))
210 EXPORT_SYMBOL_GPL(usb_find_common_endpoints_reverse);
213 * usb_find_alt_setting() - Given a configuration, find the alternate setting
214 * for the given interface.
215 * @config: the configuration to search (not necessarily the current config).
216 * @iface_num: interface number to search in
217 * @alt_num: alternate interface setting number to search for.
219 * Search the configuration's interface cache for the given alt setting.
221 * Return: The alternate setting, if found. %NULL otherwise.
223 struct usb_host_interface *usb_find_alt_setting(
224 struct usb_host_config *config,
225 unsigned int iface_num,
226 unsigned int alt_num)
228 struct usb_interface_cache *intf_cache = NULL;
231 for (i = 0; i < config->desc.bNumInterfaces; i++) {
232 if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber
234 intf_cache = config->intf_cache[i];
240 for (i = 0; i < intf_cache->num_altsetting; i++)
241 if (intf_cache->altsetting[i].desc.bAlternateSetting == alt_num)
242 return &intf_cache->altsetting[i];
244 printk(KERN_DEBUG "Did not find alt setting %u for intf %u, "
245 "config %u\n", alt_num, iface_num,
246 config->desc.bConfigurationValue);
249 EXPORT_SYMBOL_GPL(usb_find_alt_setting);
252 * usb_ifnum_to_if - get the interface object with a given interface number
253 * @dev: the device whose current configuration is considered
254 * @ifnum: the desired interface
256 * This walks the device descriptor for the currently active configuration
257 * to find the interface object with the particular interface number.
259 * Note that configuration descriptors are not required to assign interface
260 * numbers sequentially, so that it would be incorrect to assume that
261 * the first interface in that descriptor corresponds to interface zero.
262 * This routine helps device drivers avoid such mistakes.
263 * However, you should make sure that you do the right thing with any
264 * alternate settings available for this interfaces.
266 * Don't call this function unless you are bound to one of the interfaces
267 * on this device or you have locked the device!
269 * Return: A pointer to the interface that has @ifnum as interface number,
270 * if found. %NULL otherwise.
272 struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
275 struct usb_host_config *config = dev->actconfig;
280 for (i = 0; i < config->desc.bNumInterfaces; i++)
281 if (config->interface[i]->altsetting[0]
282 .desc.bInterfaceNumber == ifnum)
283 return config->interface[i];
287 EXPORT_SYMBOL_GPL(usb_ifnum_to_if);
290 * usb_altnum_to_altsetting - get the altsetting structure with a given alternate setting number.
291 * @intf: the interface containing the altsetting in question
292 * @altnum: the desired alternate setting number
294 * This searches the altsetting array of the specified interface for
295 * an entry with the correct bAlternateSetting value.
297 * Note that altsettings need not be stored sequentially by number, so
298 * it would be incorrect to assume that the first altsetting entry in
299 * the array corresponds to altsetting zero. This routine helps device
300 * drivers avoid such mistakes.
302 * Don't call this function unless you are bound to the intf interface
303 * or you have locked the device!
305 * Return: A pointer to the entry of the altsetting array of @intf that
306 * has @altnum as the alternate setting number. %NULL if not found.
308 struct usb_host_interface *usb_altnum_to_altsetting(
309 const struct usb_interface *intf,
314 for (i = 0; i < intf->num_altsetting; i++) {
315 if (intf->altsetting[i].desc.bAlternateSetting == altnum)
316 return &intf->altsetting[i];
320 EXPORT_SYMBOL_GPL(usb_altnum_to_altsetting);
322 struct find_interface_arg {
324 struct device_driver *drv;
327 static int __find_interface(struct device *dev, void *data)
329 struct find_interface_arg *arg = data;
330 struct usb_interface *intf;
332 if (!is_usb_interface(dev))
335 if (dev->driver != arg->drv)
337 intf = to_usb_interface(dev);
338 return intf->minor == arg->minor;
342 * usb_find_interface - find usb_interface pointer for driver and device
343 * @drv: the driver whose current configuration is considered
344 * @minor: the minor number of the desired device
346 * This walks the bus device list and returns a pointer to the interface
347 * with the matching minor and driver. Note, this only works for devices
348 * that share the USB major number.
350 * Return: A pointer to the interface with the matching major and @minor.
352 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
354 struct find_interface_arg argb;
358 argb.drv = &drv->drvwrap.driver;
360 dev = bus_find_device(&usb_bus_type, NULL, &argb, __find_interface);
362 /* Drop reference count from bus_find_device */
365 return dev ? to_usb_interface(dev) : NULL;
367 EXPORT_SYMBOL_GPL(usb_find_interface);
369 struct each_dev_arg {
371 int (*fn)(struct usb_device *, void *);
374 static int __each_dev(struct device *dev, void *data)
376 struct each_dev_arg *arg = (struct each_dev_arg *)data;
378 /* There are struct usb_interface on the same bus, filter them out */
379 if (!is_usb_device(dev))
382 return arg->fn(to_usb_device(dev), arg->data);
386 * usb_for_each_dev - iterate over all USB devices in the system
387 * @data: data pointer that will be handed to the callback function
388 * @fn: callback function to be called for each USB device
390 * Iterate over all USB devices and call @fn for each, passing it @data. If it
391 * returns anything other than 0, we break the iteration prematurely and return
394 int usb_for_each_dev(void *data, int (*fn)(struct usb_device *, void *))
396 struct each_dev_arg arg = {data, fn};
398 return bus_for_each_dev(&usb_bus_type, NULL, &arg, __each_dev);
400 EXPORT_SYMBOL_GPL(usb_for_each_dev);
403 * usb_release_dev - free a usb device structure when all users of it are finished.
404 * @dev: device that's been disconnected
406 * Will be called only by the device core when all users of this usb device are
409 static void usb_release_dev(struct device *dev)
411 struct usb_device *udev;
414 udev = to_usb_device(dev);
415 hcd = bus_to_hcd(udev->bus);
417 usb_destroy_configuration(udev);
418 usb_release_bos_descriptor(udev);
420 kfree(udev->product);
421 kfree(udev->manufacturer);
426 static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
428 struct usb_device *usb_dev;
430 usb_dev = to_usb_device(dev);
432 if (add_uevent_var(env, "BUSNUM=%03d", usb_dev->bus->busnum))
435 if (add_uevent_var(env, "DEVNUM=%03d", usb_dev->devnum))
443 /* USB device Power-Management thunks.
444 * There's no need to distinguish here between quiescing a USB device
445 * and powering it down; the generic_suspend() routine takes care of
446 * it by skipping the usb_port_suspend() call for a quiesce. And for
447 * USB interfaces there's no difference at all.
450 static int usb_dev_prepare(struct device *dev)
452 return 0; /* Implement eventually? */
455 static void usb_dev_complete(struct device *dev)
457 /* Currently used only for rebinding interfaces */
458 usb_resume_complete(dev);
461 static int usb_dev_suspend(struct device *dev)
463 return usb_suspend(dev, PMSG_SUSPEND);
466 static int usb_dev_resume(struct device *dev)
468 return usb_resume(dev, PMSG_RESUME);
471 static int usb_dev_freeze(struct device *dev)
473 return usb_suspend(dev, PMSG_FREEZE);
476 static int usb_dev_thaw(struct device *dev)
478 return usb_resume(dev, PMSG_THAW);
481 static int usb_dev_poweroff(struct device *dev)
483 return usb_suspend(dev, PMSG_HIBERNATE);
486 static int usb_dev_restore(struct device *dev)
488 return usb_resume(dev, PMSG_RESTORE);
491 static const struct dev_pm_ops usb_device_pm_ops = {
492 .prepare = usb_dev_prepare,
493 .complete = usb_dev_complete,
494 .suspend = usb_dev_suspend,
495 .resume = usb_dev_resume,
496 .freeze = usb_dev_freeze,
497 .thaw = usb_dev_thaw,
498 .poweroff = usb_dev_poweroff,
499 .restore = usb_dev_restore,
500 .runtime_suspend = usb_runtime_suspend,
501 .runtime_resume = usb_runtime_resume,
502 .runtime_idle = usb_runtime_idle,
505 #endif /* CONFIG_PM */
508 static char *usb_devnode(struct device *dev,
509 umode_t *mode, kuid_t *uid, kgid_t *gid)
511 struct usb_device *usb_dev;
513 usb_dev = to_usb_device(dev);
514 return kasprintf(GFP_KERNEL, "bus/usb/%03d/%03d",
515 usb_dev->bus->busnum, usb_dev->devnum);
518 struct device_type usb_device_type = {
519 .name = "usb_device",
520 .release = usb_release_dev,
521 .uevent = usb_dev_uevent,
522 .devnode = usb_devnode,
524 .pm = &usb_device_pm_ops,
529 /* Returns 1 if @usb_bus is WUSB, 0 otherwise */
530 static unsigned usb_bus_is_wusb(struct usb_bus *bus)
532 struct usb_hcd *hcd = bus_to_hcd(bus);
533 return hcd->wireless;
538 * usb_alloc_dev - usb device constructor (usbcore-internal)
539 * @parent: hub to which device is connected; null to allocate a root hub
540 * @bus: bus used to access the device
541 * @port1: one-based index of port; ignored for root hubs
542 * Context: !in_interrupt()
544 * Only hub drivers (including virtual root hub drivers for host
545 * controllers) should ever call this.
547 * This call may not be used in a non-sleeping context.
549 * Return: On success, a pointer to the allocated usb device. %NULL on
552 struct usb_device *usb_alloc_dev(struct usb_device *parent,
553 struct usb_bus *bus, unsigned port1)
555 struct usb_device *dev;
556 struct usb_hcd *usb_hcd = bus_to_hcd(bus);
557 unsigned root_hub = 0;
558 unsigned raw_port = port1;
560 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
564 if (!usb_get_hcd(usb_hcd)) {
568 /* Root hubs aren't true devices, so don't allocate HCD resources */
569 if (usb_hcd->driver->alloc_dev && parent &&
570 !usb_hcd->driver->alloc_dev(usb_hcd, dev)) {
571 usb_put_hcd(bus_to_hcd(bus));
576 device_initialize(&dev->dev);
577 dev->dev.bus = &usb_bus_type;
578 dev->dev.type = &usb_device_type;
579 dev->dev.groups = usb_device_groups;
581 * Fake a dma_mask/offset for the USB device:
582 * We cannot really use the dma-mapping API (dma_alloc_* and
583 * dma_map_*) for USB devices but instead need to use
584 * usb_alloc_coherent and pass data in 'urb's, but some subsystems
585 * manually look into the mask/offset pair to determine whether
586 * they need bounce buffers.
587 * Note: calling dma_set_mask() on a USB device would set the
588 * mask for the entire HCD, so don't do that.
590 dev->dev.dma_mask = bus->sysdev->dma_mask;
591 dev->dev.dma_pfn_offset = bus->sysdev->dma_pfn_offset;
592 set_dev_node(&dev->dev, dev_to_node(bus->sysdev));
593 dev->state = USB_STATE_ATTACHED;
594 dev->lpm_disable_count = 1;
595 atomic_set(&dev->urbnum, 0);
597 INIT_LIST_HEAD(&dev->ep0.urb_list);
598 dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
599 dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
600 /* ep0 maxpacket comes later, from device descriptor */
601 usb_enable_endpoint(dev, &dev->ep0, false);
604 /* Save readable and stable topology id, distinguishing devices
605 * by location for diagnostics, tools, driver model, etc. The
606 * string is a path along hub ports, from the root. Each device's
607 * dev->devpath will be stable until USB is re-cabled, and hubs
608 * are often labeled with these port numbers. The name isn't
609 * as stable: bus->busnum changes easily from modprobe order,
610 * cardbus or pci hotplugging, and so on.
612 if (unlikely(!parent)) {
613 dev->devpath[0] = '0';
616 dev->dev.parent = bus->controller;
617 dev_set_name(&dev->dev, "usb%d", bus->busnum);
620 /* match any labeling on the hubs; it's one-based */
621 if (parent->devpath[0] == '0') {
622 snprintf(dev->devpath, sizeof dev->devpath,
624 /* Root ports are not counted in route string */
627 snprintf(dev->devpath, sizeof dev->devpath,
628 "%s.%d", parent->devpath, port1);
629 /* Route string assumes hubs have less than 16 ports */
631 dev->route = parent->route +
632 (port1 << ((parent->level - 1)*4));
634 dev->route = parent->route +
635 (15 << ((parent->level - 1)*4));
638 dev->dev.parent = &parent->dev;
639 dev_set_name(&dev->dev, "%d-%s", bus->busnum, dev->devpath);
641 if (!parent->parent) {
642 /* device under root hub's port */
643 raw_port = usb_hcd_find_raw_port_number(usb_hcd,
646 dev->dev.of_node = usb_of_get_child_node(parent->dev.of_node,
649 /* hub driver sets up TT records */
652 dev->portnum = port1;
654 dev->parent = parent;
655 INIT_LIST_HEAD(&dev->filelist);
658 pm_runtime_set_autosuspend_delay(&dev->dev,
659 usb_autosuspend_delay * 1000);
660 dev->connect_time = jiffies;
661 dev->active_duration = -jiffies;
663 if (root_hub) /* Root hub always ok [and always wired] */
666 dev->authorized = !!HCD_DEV_AUTHORIZED(usb_hcd);
667 dev->wusb = usb_bus_is_wusb(bus) ? 1 : 0;
671 EXPORT_SYMBOL_GPL(usb_alloc_dev);
674 * usb_get_dev - increments the reference count of the usb device structure
675 * @dev: the device being referenced
677 * Each live reference to a device should be refcounted.
679 * Drivers for USB interfaces should normally record such references in
680 * their probe() methods, when they bind to an interface, and release
681 * them by calling usb_put_dev(), in their disconnect() methods.
683 * Return: A pointer to the device with the incremented reference counter.
685 struct usb_device *usb_get_dev(struct usb_device *dev)
688 get_device(&dev->dev);
691 EXPORT_SYMBOL_GPL(usb_get_dev);
694 * usb_put_dev - release a use of the usb device structure
695 * @dev: device that's been disconnected
697 * Must be called when a user of a device is finished with it. When the last
698 * user of the device calls this function, the memory of the device is freed.
700 void usb_put_dev(struct usb_device *dev)
703 put_device(&dev->dev);
705 EXPORT_SYMBOL_GPL(usb_put_dev);
708 * usb_get_intf - increments the reference count of the usb interface structure
709 * @intf: the interface being referenced
711 * Each live reference to a interface must be refcounted.
713 * Drivers for USB interfaces should normally record such references in
714 * their probe() methods, when they bind to an interface, and release
715 * them by calling usb_put_intf(), in their disconnect() methods.
717 * Return: A pointer to the interface with the incremented reference counter.
719 struct usb_interface *usb_get_intf(struct usb_interface *intf)
722 get_device(&intf->dev);
725 EXPORT_SYMBOL_GPL(usb_get_intf);
728 * usb_put_intf - release a use of the usb interface structure
729 * @intf: interface that's been decremented
731 * Must be called when a user of an interface is finished with it. When the
732 * last user of the interface calls this function, the memory of the interface
735 void usb_put_intf(struct usb_interface *intf)
738 put_device(&intf->dev);
740 EXPORT_SYMBOL_GPL(usb_put_intf);
742 /* USB device locking
744 * USB devices and interfaces are locked using the semaphore in their
745 * embedded struct device. The hub driver guarantees that whenever a
746 * device is connected or disconnected, drivers are called with the
747 * USB device locked as well as their particular interface.
749 * Complications arise when several devices are to be locked at the same
750 * time. Only hub-aware drivers that are part of usbcore ever have to
751 * do this; nobody else needs to worry about it. The rule for locking
754 * When locking both a device and its parent, always lock the
759 * usb_lock_device_for_reset - cautiously acquire the lock for a usb device structure
760 * @udev: device that's being locked
761 * @iface: interface bound to the driver making the request (optional)
763 * Attempts to acquire the device lock, but fails if the device is
764 * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
765 * is neither BINDING nor BOUND. Rather than sleeping to wait for the
766 * lock, the routine polls repeatedly. This is to prevent deadlock with
767 * disconnect; in some drivers (such as usb-storage) the disconnect()
768 * or suspend() method will block waiting for a device reset to complete.
770 * Return: A negative error code for failure, otherwise 0.
772 int usb_lock_device_for_reset(struct usb_device *udev,
773 const struct usb_interface *iface)
775 unsigned long jiffies_expire = jiffies + HZ;
777 if (udev->state == USB_STATE_NOTATTACHED)
779 if (udev->state == USB_STATE_SUSPENDED)
780 return -EHOSTUNREACH;
781 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
782 iface->condition == USB_INTERFACE_UNBOUND))
785 while (!usb_trylock_device(udev)) {
787 /* If we can't acquire the lock after waiting one second,
788 * we're probably deadlocked */
789 if (time_after(jiffies, jiffies_expire))
793 if (udev->state == USB_STATE_NOTATTACHED)
795 if (udev->state == USB_STATE_SUSPENDED)
796 return -EHOSTUNREACH;
797 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
798 iface->condition == USB_INTERFACE_UNBOUND))
803 EXPORT_SYMBOL_GPL(usb_lock_device_for_reset);
806 * usb_get_current_frame_number - return current bus frame number
807 * @dev: the device whose bus is being queried
809 * Return: The current frame number for the USB host controller used
810 * with the given USB device. This can be used when scheduling
811 * isochronous requests.
813 * Note: Different kinds of host controller have different "scheduling
814 * horizons". While one type might support scheduling only 32 frames
815 * into the future, others could support scheduling up to 1024 frames
819 int usb_get_current_frame_number(struct usb_device *dev)
821 return usb_hcd_get_frame_number(dev);
823 EXPORT_SYMBOL_GPL(usb_get_current_frame_number);
825 /*-------------------------------------------------------------------*/
827 * __usb_get_extra_descriptor() finds a descriptor of specific type in the
828 * extra field of the interface and endpoint descriptor structs.
831 int __usb_get_extra_descriptor(char *buffer, unsigned size,
832 unsigned char type, void **ptr)
834 struct usb_descriptor_header *header;
836 while (size >= sizeof(struct usb_descriptor_header)) {
837 header = (struct usb_descriptor_header *)buffer;
839 if (header->bLength < 2) {
841 "%s: bogus descriptor, type %d length %d\n",
843 header->bDescriptorType,
848 if (header->bDescriptorType == type) {
853 buffer += header->bLength;
854 size -= header->bLength;
858 EXPORT_SYMBOL_GPL(__usb_get_extra_descriptor);
861 * usb_alloc_coherent - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
862 * @dev: device the buffer will be used with
863 * @size: requested buffer size
864 * @mem_flags: affect whether allocation may block
865 * @dma: used to return DMA address of buffer
867 * Return: Either null (indicating no buffer could be allocated), or the
868 * cpu-space pointer to a buffer that may be used to perform DMA to the
869 * specified device. Such cpu-space buffers are returned along with the DMA
870 * address (through the pointer provided).
873 * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
874 * to avoid behaviors like using "DMA bounce buffers", or thrashing IOMMU
875 * hardware during URB completion/resubmit. The implementation varies between
876 * platforms, depending on details of how DMA will work to this device.
877 * Using these buffers also eliminates cacheline sharing problems on
878 * architectures where CPU caches are not DMA-coherent. On systems without
879 * bus-snooping caches, these buffers are uncached.
881 * When the buffer is no longer used, free it with usb_free_coherent().
883 void *usb_alloc_coherent(struct usb_device *dev, size_t size, gfp_t mem_flags,
886 if (!dev || !dev->bus)
888 return hcd_buffer_alloc(dev->bus, size, mem_flags, dma);
890 EXPORT_SYMBOL_GPL(usb_alloc_coherent);
893 * usb_free_coherent - free memory allocated with usb_alloc_coherent()
894 * @dev: device the buffer was used with
895 * @size: requested buffer size
896 * @addr: CPU address of buffer
897 * @dma: DMA address of buffer
899 * This reclaims an I/O buffer, letting it be reused. The memory must have
900 * been allocated using usb_alloc_coherent(), and the parameters must match
901 * those provided in that allocation request.
903 void usb_free_coherent(struct usb_device *dev, size_t size, void *addr,
906 if (!dev || !dev->bus)
910 hcd_buffer_free(dev->bus, size, addr, dma);
912 EXPORT_SYMBOL_GPL(usb_free_coherent);
915 * usb_buffer_map - create DMA mapping(s) for an urb
916 * @urb: urb whose transfer_buffer/setup_packet will be mapped
918 * URB_NO_TRANSFER_DMA_MAP is added to urb->transfer_flags if the operation
919 * succeeds. If the device is connected to this system through a non-DMA
920 * controller, this operation always succeeds.
922 * This call would normally be used for an urb which is reused, perhaps
923 * as the target of a large periodic transfer, with usb_buffer_dmasync()
924 * calls to synchronize memory and dma state.
926 * Reverse the effect of this call with usb_buffer_unmap().
928 * Return: Either %NULL (indicating no buffer could be mapped), or @urb.
932 struct urb *usb_buffer_map(struct urb *urb)
935 struct device *controller;
939 || !(bus = urb->dev->bus)
940 || !(controller = bus->sysdev))
943 if (controller->dma_mask) {
944 urb->transfer_dma = dma_map_single(controller,
945 urb->transfer_buffer, urb->transfer_buffer_length,
946 usb_pipein(urb->pipe)
947 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
948 /* FIXME generic api broken like pci, can't report errors */
949 /* if (urb->transfer_dma == DMA_ADDR_INVALID) return 0; */
951 urb->transfer_dma = ~0;
952 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
955 EXPORT_SYMBOL_GPL(usb_buffer_map);
958 /* XXX DISABLED, no users currently. If you wish to re-enable this
959 * XXX please determine whether the sync is to transfer ownership of
960 * XXX the buffer from device to cpu or vice verse, and thusly use the
961 * XXX appropriate _for_{cpu,device}() method. -DaveM
966 * usb_buffer_dmasync - synchronize DMA and CPU view of buffer(s)
967 * @urb: urb whose transfer_buffer/setup_packet will be synchronized
969 void usb_buffer_dmasync(struct urb *urb)
972 struct device *controller;
975 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
977 || !(bus = urb->dev->bus)
978 || !(controller = bus->sysdev))
981 if (controller->dma_mask) {
982 dma_sync_single_for_cpu(controller,
983 urb->transfer_dma, urb->transfer_buffer_length,
984 usb_pipein(urb->pipe)
985 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
986 if (usb_pipecontrol(urb->pipe))
987 dma_sync_single_for_cpu(controller,
989 sizeof(struct usb_ctrlrequest),
993 EXPORT_SYMBOL_GPL(usb_buffer_dmasync);
997 * usb_buffer_unmap - free DMA mapping(s) for an urb
998 * @urb: urb whose transfer_buffer will be unmapped
1000 * Reverses the effect of usb_buffer_map().
1003 void usb_buffer_unmap(struct urb *urb)
1005 struct usb_bus *bus;
1006 struct device *controller;
1009 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
1011 || !(bus = urb->dev->bus)
1012 || !(controller = bus->sysdev))
1015 if (controller->dma_mask) {
1016 dma_unmap_single(controller,
1017 urb->transfer_dma, urb->transfer_buffer_length,
1018 usb_pipein(urb->pipe)
1019 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
1021 urb->transfer_flags &= ~URB_NO_TRANSFER_DMA_MAP;
1023 EXPORT_SYMBOL_GPL(usb_buffer_unmap);
1028 * usb_buffer_map_sg - create scatterlist DMA mapping(s) for an endpoint
1029 * @dev: device to which the scatterlist will be mapped
1030 * @is_in: mapping transfer direction
1031 * @sg: the scatterlist to map
1032 * @nents: the number of entries in the scatterlist
1034 * Return: Either < 0 (indicating no buffers could be mapped), or the
1035 * number of DMA mapping array entries in the scatterlist.
1038 * The caller is responsible for placing the resulting DMA addresses from
1039 * the scatterlist into URB transfer buffer pointers, and for setting the
1040 * URB_NO_TRANSFER_DMA_MAP transfer flag in each of those URBs.
1042 * Top I/O rates come from queuing URBs, instead of waiting for each one
1043 * to complete before starting the next I/O. This is particularly easy
1044 * to do with scatterlists. Just allocate and submit one URB for each DMA
1045 * mapping entry returned, stopping on the first error or when all succeed.
1046 * Better yet, use the usb_sg_*() calls, which do that (and more) for you.
1048 * This call would normally be used when translating scatterlist requests,
1049 * rather than usb_buffer_map(), since on some hardware (with IOMMUs) it
1050 * may be able to coalesce mappings for improved I/O efficiency.
1052 * Reverse the effect of this call with usb_buffer_unmap_sg().
1054 int usb_buffer_map_sg(const struct usb_device *dev, int is_in,
1055 struct scatterlist *sg, int nents)
1057 struct usb_bus *bus;
1058 struct device *controller;
1061 || !(bus = dev->bus)
1062 || !(controller = bus->sysdev)
1063 || !controller->dma_mask)
1066 /* FIXME generic api broken like pci, can't report errors */
1067 return dma_map_sg(controller, sg, nents,
1068 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE) ? : -ENOMEM;
1070 EXPORT_SYMBOL_GPL(usb_buffer_map_sg);
1073 /* XXX DISABLED, no users currently. If you wish to re-enable this
1074 * XXX please determine whether the sync is to transfer ownership of
1075 * XXX the buffer from device to cpu or vice verse, and thusly use the
1076 * XXX appropriate _for_{cpu,device}() method. -DaveM
1081 * usb_buffer_dmasync_sg - synchronize DMA and CPU view of scatterlist buffer(s)
1082 * @dev: device to which the scatterlist will be mapped
1083 * @is_in: mapping transfer direction
1084 * @sg: the scatterlist to synchronize
1085 * @n_hw_ents: the positive return value from usb_buffer_map_sg
1087 * Use this when you are re-using a scatterlist's data buffers for
1088 * another USB request.
1090 void usb_buffer_dmasync_sg(const struct usb_device *dev, int is_in,
1091 struct scatterlist *sg, int n_hw_ents)
1093 struct usb_bus *bus;
1094 struct device *controller;
1097 || !(bus = dev->bus)
1098 || !(controller = bus->sysdev)
1099 || !controller->dma_mask)
1102 dma_sync_sg_for_cpu(controller, sg, n_hw_ents,
1103 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
1105 EXPORT_SYMBOL_GPL(usb_buffer_dmasync_sg);
1110 * usb_buffer_unmap_sg - free DMA mapping(s) for a scatterlist
1111 * @dev: device to which the scatterlist will be mapped
1112 * @is_in: mapping transfer direction
1113 * @sg: the scatterlist to unmap
1114 * @n_hw_ents: the positive return value from usb_buffer_map_sg
1116 * Reverses the effect of usb_buffer_map_sg().
1118 void usb_buffer_unmap_sg(const struct usb_device *dev, int is_in,
1119 struct scatterlist *sg, int n_hw_ents)
1121 struct usb_bus *bus;
1122 struct device *controller;
1125 || !(bus = dev->bus)
1126 || !(controller = bus->sysdev)
1127 || !controller->dma_mask)
1130 dma_unmap_sg(controller, sg, n_hw_ents,
1131 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
1133 EXPORT_SYMBOL_GPL(usb_buffer_unmap_sg);
1137 * Notifications of device and interface registration
1139 static int usb_bus_notify(struct notifier_block *nb, unsigned long action,
1142 struct device *dev = data;
1145 case BUS_NOTIFY_ADD_DEVICE:
1146 if (dev->type == &usb_device_type)
1147 (void) usb_create_sysfs_dev_files(to_usb_device(dev));
1148 else if (dev->type == &usb_if_device_type)
1149 usb_create_sysfs_intf_files(to_usb_interface(dev));
1152 case BUS_NOTIFY_DEL_DEVICE:
1153 if (dev->type == &usb_device_type)
1154 usb_remove_sysfs_dev_files(to_usb_device(dev));
1155 else if (dev->type == &usb_if_device_type)
1156 usb_remove_sysfs_intf_files(to_usb_interface(dev));
1162 static struct notifier_block usb_bus_nb = {
1163 .notifier_call = usb_bus_notify,
1166 struct dentry *usb_debug_root;
1167 EXPORT_SYMBOL_GPL(usb_debug_root);
1169 static struct dentry *usb_debug_devices;
1171 static int usb_debugfs_init(void)
1173 usb_debug_root = debugfs_create_dir("usb", NULL);
1174 if (!usb_debug_root)
1177 usb_debug_devices = debugfs_create_file("devices", 0444,
1178 usb_debug_root, NULL,
1179 &usbfs_devices_fops);
1180 if (!usb_debug_devices) {
1181 debugfs_remove(usb_debug_root);
1182 usb_debug_root = NULL;
1189 static void usb_debugfs_cleanup(void)
1191 debugfs_remove(usb_debug_devices);
1192 debugfs_remove(usb_debug_root);
1198 static int __init usb_init(void)
1201 if (usb_disabled()) {
1202 pr_info("%s: USB support disabled\n", usbcore_name);
1205 usb_init_pool_max();
1207 retval = usb_debugfs_init();
1211 usb_acpi_register();
1212 retval = bus_register(&usb_bus_type);
1214 goto bus_register_failed;
1215 retval = bus_register_notifier(&usb_bus_type, &usb_bus_nb);
1217 goto bus_notifier_failed;
1218 retval = usb_major_init();
1220 goto major_init_failed;
1221 retval = usb_register(&usbfs_driver);
1223 goto driver_register_failed;
1224 retval = usb_devio_init();
1226 goto usb_devio_init_failed;
1227 retval = usb_hub_init();
1229 goto hub_init_failed;
1230 retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
1236 usb_devio_cleanup();
1237 usb_devio_init_failed:
1238 usb_deregister(&usbfs_driver);
1239 driver_register_failed:
1240 usb_major_cleanup();
1242 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1243 bus_notifier_failed:
1244 bus_unregister(&usb_bus_type);
1245 bus_register_failed:
1246 usb_acpi_unregister();
1247 usb_debugfs_cleanup();
1255 static void __exit usb_exit(void)
1257 /* This will matter if shutdown/reboot does exitcalls. */
1261 usb_deregister_device_driver(&usb_generic_driver);
1262 usb_major_cleanup();
1263 usb_deregister(&usbfs_driver);
1264 usb_devio_cleanup();
1266 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1267 bus_unregister(&usb_bus_type);
1268 usb_acpi_unregister();
1269 usb_debugfs_cleanup();
1270 idr_destroy(&usb_bus_idr);
1273 subsys_initcall(usb_init);
1274 module_exit(usb_exit);
1275 MODULE_LICENSE("GPL");