1 // SPDX-License-Identifier: GPL-2.0
3 * drivers/usb/core/usb.c
5 * (C) Copyright Linus Torvalds 1999
6 * (C) Copyright Johannes Erdfelt 1999-2001
7 * (C) Copyright Andreas Gal 1999
8 * (C) Copyright Gregory P. Smith 1999
9 * (C) Copyright Deti Fliegl 1999 (new USB architecture)
10 * (C) Copyright Randy Dunlap 2000
11 * (C) Copyright David Brownell 2000-2004
12 * (C) Copyright Yggdrasil Computing, Inc. 2000
13 * (usb_device_id matching changes by Adam J. Richter)
14 * (C) Copyright Greg Kroah-Hartman 2002-2003
16 * Released under the GPLv2 only.
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_endpoint() - Given an endpoint address, search for the endpoint's
214 * usb_host_endpoint structure in an interface's current altsetting.
215 * @intf: the interface whose current altsetting should be searched
216 * @ep_addr: the endpoint address (number and direction) to find
218 * Search the altsetting's list of endpoints for one with the specified address.
220 * Return: Pointer to the usb_host_endpoint if found, %NULL otherwise.
222 static const struct usb_host_endpoint *usb_find_endpoint(
223 const struct usb_interface *intf, unsigned int ep_addr)
226 const struct usb_host_endpoint *ep;
228 n = intf->cur_altsetting->desc.bNumEndpoints;
229 ep = intf->cur_altsetting->endpoint;
230 for (; n > 0; (--n, ++ep)) {
231 if (ep->desc.bEndpointAddress == ep_addr)
238 * usb_check_bulk_endpoints - Check whether an interface's current altsetting
239 * contains a set of bulk endpoints with the given addresses.
240 * @intf: the interface whose current altsetting should be searched
241 * @ep_addrs: 0-terminated array of the endpoint addresses (number and
242 * direction) to look for
244 * Search for endpoints with the specified addresses and check their types.
246 * Return: %true if all the endpoints are found and are bulk, %false otherwise.
248 bool usb_check_bulk_endpoints(
249 const struct usb_interface *intf, const u8 *ep_addrs)
251 const struct usb_host_endpoint *ep;
253 for (; *ep_addrs; ++ep_addrs) {
254 ep = usb_find_endpoint(intf, *ep_addrs);
255 if (!ep || !usb_endpoint_xfer_bulk(&ep->desc))
260 EXPORT_SYMBOL_GPL(usb_check_bulk_endpoints);
263 * usb_check_int_endpoints - Check whether an interface's current altsetting
264 * contains a set of interrupt endpoints with the given addresses.
265 * @intf: the interface whose current altsetting should be searched
266 * @ep_addrs: 0-terminated array of the endpoint addresses (number and
267 * direction) to look for
269 * Search for endpoints with the specified addresses and check their types.
271 * Return: %true if all the endpoints are found and are interrupt,
274 bool usb_check_int_endpoints(
275 const struct usb_interface *intf, const u8 *ep_addrs)
277 const struct usb_host_endpoint *ep;
279 for (; *ep_addrs; ++ep_addrs) {
280 ep = usb_find_endpoint(intf, *ep_addrs);
281 if (!ep || !usb_endpoint_xfer_int(&ep->desc))
286 EXPORT_SYMBOL_GPL(usb_check_int_endpoints);
289 * usb_find_alt_setting() - Given a configuration, find the alternate setting
290 * for the given interface.
291 * @config: the configuration to search (not necessarily the current config).
292 * @iface_num: interface number to search in
293 * @alt_num: alternate interface setting number to search for.
295 * Search the configuration's interface cache for the given alt setting.
297 * Return: The alternate setting, if found. %NULL otherwise.
299 struct usb_host_interface *usb_find_alt_setting(
300 struct usb_host_config *config,
301 unsigned int iface_num,
302 unsigned int alt_num)
304 struct usb_interface_cache *intf_cache = NULL;
309 for (i = 0; i < config->desc.bNumInterfaces; i++) {
310 if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber
312 intf_cache = config->intf_cache[i];
318 for (i = 0; i < intf_cache->num_altsetting; i++)
319 if (intf_cache->altsetting[i].desc.bAlternateSetting == alt_num)
320 return &intf_cache->altsetting[i];
322 printk(KERN_DEBUG "Did not find alt setting %u for intf %u, "
323 "config %u\n", alt_num, iface_num,
324 config->desc.bConfigurationValue);
327 EXPORT_SYMBOL_GPL(usb_find_alt_setting);
330 * usb_ifnum_to_if - get the interface object with a given interface number
331 * @dev: the device whose current configuration is considered
332 * @ifnum: the desired interface
334 * This walks the device descriptor for the currently active configuration
335 * to find the interface object with the particular interface number.
337 * Note that configuration descriptors are not required to assign interface
338 * numbers sequentially, so that it would be incorrect to assume that
339 * the first interface in that descriptor corresponds to interface zero.
340 * This routine helps device drivers avoid such mistakes.
341 * However, you should make sure that you do the right thing with any
342 * alternate settings available for this interfaces.
344 * Don't call this function unless you are bound to one of the interfaces
345 * on this device or you have locked the device!
347 * Return: A pointer to the interface that has @ifnum as interface number,
348 * if found. %NULL otherwise.
350 struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
353 struct usb_host_config *config = dev->actconfig;
358 for (i = 0; i < config->desc.bNumInterfaces; i++)
359 if (config->interface[i]->altsetting[0]
360 .desc.bInterfaceNumber == ifnum)
361 return config->interface[i];
365 EXPORT_SYMBOL_GPL(usb_ifnum_to_if);
368 * usb_altnum_to_altsetting - get the altsetting structure with a given alternate setting number.
369 * @intf: the interface containing the altsetting in question
370 * @altnum: the desired alternate setting number
372 * This searches the altsetting array of the specified interface for
373 * an entry with the correct bAlternateSetting value.
375 * Note that altsettings need not be stored sequentially by number, so
376 * it would be incorrect to assume that the first altsetting entry in
377 * the array corresponds to altsetting zero. This routine helps device
378 * drivers avoid such mistakes.
380 * Don't call this function unless you are bound to the intf interface
381 * or you have locked the device!
383 * Return: A pointer to the entry of the altsetting array of @intf that
384 * has @altnum as the alternate setting number. %NULL if not found.
386 struct usb_host_interface *usb_altnum_to_altsetting(
387 const struct usb_interface *intf,
392 for (i = 0; i < intf->num_altsetting; i++) {
393 if (intf->altsetting[i].desc.bAlternateSetting == altnum)
394 return &intf->altsetting[i];
398 EXPORT_SYMBOL_GPL(usb_altnum_to_altsetting);
400 struct find_interface_arg {
402 struct device_driver *drv;
405 static int __find_interface(struct device *dev, void *data)
407 struct find_interface_arg *arg = data;
408 struct usb_interface *intf;
410 if (!is_usb_interface(dev))
413 if (dev->driver != arg->drv)
415 intf = to_usb_interface(dev);
416 return intf->minor == arg->minor;
420 * usb_find_interface - find usb_interface pointer for driver and device
421 * @drv: the driver whose current configuration is considered
422 * @minor: the minor number of the desired device
424 * This walks the bus device list and returns a pointer to the interface
425 * with the matching minor and driver. Note, this only works for devices
426 * that share the USB major number.
428 * Return: A pointer to the interface with the matching major and @minor.
430 struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
432 struct find_interface_arg argb;
436 argb.drv = &drv->drvwrap.driver;
438 dev = bus_find_device(&usb_bus_type, NULL, &argb, __find_interface);
440 /* Drop reference count from bus_find_device */
443 return dev ? to_usb_interface(dev) : NULL;
445 EXPORT_SYMBOL_GPL(usb_find_interface);
447 struct each_dev_arg {
449 int (*fn)(struct usb_device *, void *);
452 static int __each_dev(struct device *dev, void *data)
454 struct each_dev_arg *arg = (struct each_dev_arg *)data;
456 /* There are struct usb_interface on the same bus, filter them out */
457 if (!is_usb_device(dev))
460 return arg->fn(to_usb_device(dev), arg->data);
464 * usb_for_each_dev - iterate over all USB devices in the system
465 * @data: data pointer that will be handed to the callback function
466 * @fn: callback function to be called for each USB device
468 * Iterate over all USB devices and call @fn for each, passing it @data. If it
469 * returns anything other than 0, we break the iteration prematurely and return
472 int usb_for_each_dev(void *data, int (*fn)(struct usb_device *, void *))
474 struct each_dev_arg arg = {data, fn};
476 return bus_for_each_dev(&usb_bus_type, NULL, &arg, __each_dev);
478 EXPORT_SYMBOL_GPL(usb_for_each_dev);
481 * usb_release_dev - free a usb device structure when all users of it are finished.
482 * @dev: device that's been disconnected
484 * Will be called only by the device core when all users of this usb device are
487 static void usb_release_dev(struct device *dev)
489 struct usb_device *udev;
492 udev = to_usb_device(dev);
493 hcd = bus_to_hcd(udev->bus);
495 usb_destroy_configuration(udev);
496 usb_release_bos_descriptor(udev);
497 of_node_put(dev->of_node);
499 kfree(udev->product);
500 kfree(udev->manufacturer);
505 static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
507 struct usb_device *usb_dev;
509 usb_dev = to_usb_device(dev);
511 if (add_uevent_var(env, "BUSNUM=%03d", usb_dev->bus->busnum))
514 if (add_uevent_var(env, "DEVNUM=%03d", usb_dev->devnum))
522 /* USB device Power-Management thunks.
523 * There's no need to distinguish here between quiescing a USB device
524 * and powering it down; the generic_suspend() routine takes care of
525 * it by skipping the usb_port_suspend() call for a quiesce. And for
526 * USB interfaces there's no difference at all.
529 static int usb_dev_prepare(struct device *dev)
531 return 0; /* Implement eventually? */
534 static void usb_dev_complete(struct device *dev)
536 /* Currently used only for rebinding interfaces */
537 usb_resume_complete(dev);
540 static int usb_dev_suspend(struct device *dev)
542 return usb_suspend(dev, PMSG_SUSPEND);
545 static int usb_dev_resume(struct device *dev)
547 return usb_resume(dev, PMSG_RESUME);
550 static int usb_dev_freeze(struct device *dev)
552 return usb_suspend(dev, PMSG_FREEZE);
555 static int usb_dev_thaw(struct device *dev)
557 return usb_resume(dev, PMSG_THAW);
560 static int usb_dev_poweroff(struct device *dev)
562 return usb_suspend(dev, PMSG_HIBERNATE);
565 static int usb_dev_restore(struct device *dev)
567 return usb_resume(dev, PMSG_RESTORE);
570 static const struct dev_pm_ops usb_device_pm_ops = {
571 .prepare = usb_dev_prepare,
572 .complete = usb_dev_complete,
573 .suspend = usb_dev_suspend,
574 .resume = usb_dev_resume,
575 .freeze = usb_dev_freeze,
576 .thaw = usb_dev_thaw,
577 .poweroff = usb_dev_poweroff,
578 .restore = usb_dev_restore,
579 .runtime_suspend = usb_runtime_suspend,
580 .runtime_resume = usb_runtime_resume,
581 .runtime_idle = usb_runtime_idle,
584 #endif /* CONFIG_PM */
587 static char *usb_devnode(struct device *dev,
588 umode_t *mode, kuid_t *uid, kgid_t *gid)
590 struct usb_device *usb_dev;
592 usb_dev = to_usb_device(dev);
593 return kasprintf(GFP_KERNEL, "bus/usb/%03d/%03d",
594 usb_dev->bus->busnum, usb_dev->devnum);
597 struct device_type usb_device_type = {
598 .name = "usb_device",
599 .release = usb_release_dev,
600 .uevent = usb_dev_uevent,
601 .devnode = usb_devnode,
603 .pm = &usb_device_pm_ops,
608 /* Returns 1 if @usb_bus is WUSB, 0 otherwise */
609 static unsigned usb_bus_is_wusb(struct usb_bus *bus)
611 struct usb_hcd *hcd = bus_to_hcd(bus);
612 return hcd->wireless;
617 * usb_alloc_dev - usb device constructor (usbcore-internal)
618 * @parent: hub to which device is connected; null to allocate a root hub
619 * @bus: bus used to access the device
620 * @port1: one-based index of port; ignored for root hubs
621 * Context: !in_interrupt()
623 * Only hub drivers (including virtual root hub drivers for host
624 * controllers) should ever call this.
626 * This call may not be used in a non-sleeping context.
628 * Return: On success, a pointer to the allocated usb device. %NULL on
631 struct usb_device *usb_alloc_dev(struct usb_device *parent,
632 struct usb_bus *bus, unsigned port1)
634 struct usb_device *dev;
635 struct usb_hcd *usb_hcd = bus_to_hcd(bus);
636 unsigned root_hub = 0;
637 unsigned raw_port = port1;
639 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
643 if (!usb_get_hcd(usb_hcd)) {
647 /* Root hubs aren't true devices, so don't allocate HCD resources */
648 if (usb_hcd->driver->alloc_dev && parent &&
649 !usb_hcd->driver->alloc_dev(usb_hcd, dev)) {
650 usb_put_hcd(bus_to_hcd(bus));
655 device_initialize(&dev->dev);
656 dev->dev.bus = &usb_bus_type;
657 dev->dev.type = &usb_device_type;
658 dev->dev.groups = usb_device_groups;
660 * Fake a dma_mask/offset for the USB device:
661 * We cannot really use the dma-mapping API (dma_alloc_* and
662 * dma_map_*) for USB devices but instead need to use
663 * usb_alloc_coherent and pass data in 'urb's, but some subsystems
664 * manually look into the mask/offset pair to determine whether
665 * they need bounce buffers.
666 * Note: calling dma_set_mask() on a USB device would set the
667 * mask for the entire HCD, so don't do that.
669 dev->dev.dma_mask = bus->sysdev->dma_mask;
670 dev->dev.dma_pfn_offset = bus->sysdev->dma_pfn_offset;
671 set_dev_node(&dev->dev, dev_to_node(bus->sysdev));
672 dev->state = USB_STATE_ATTACHED;
673 dev->lpm_disable_count = 1;
674 atomic_set(&dev->urbnum, 0);
676 INIT_LIST_HEAD(&dev->ep0.urb_list);
677 dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
678 dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
679 /* ep0 maxpacket comes later, from device descriptor */
680 usb_enable_endpoint(dev, &dev->ep0, false);
683 /* Save readable and stable topology id, distinguishing devices
684 * by location for diagnostics, tools, driver model, etc. The
685 * string is a path along hub ports, from the root. Each device's
686 * dev->devpath will be stable until USB is re-cabled, and hubs
687 * are often labeled with these port numbers. The name isn't
688 * as stable: bus->busnum changes easily from modprobe order,
689 * cardbus or pci hotplugging, and so on.
691 if (unlikely(!parent)) {
692 dev->devpath[0] = '0';
695 dev->dev.parent = bus->controller;
696 device_set_of_node_from_dev(&dev->dev, bus->sysdev);
697 dev_set_name(&dev->dev, "usb%d", bus->busnum);
700 /* match any labeling on the hubs; it's one-based */
701 if (parent->devpath[0] == '0') {
702 snprintf(dev->devpath, sizeof dev->devpath,
704 /* Root ports are not counted in route string */
707 snprintf(dev->devpath, sizeof dev->devpath,
708 "%s.%d", parent->devpath, port1);
709 /* Route string assumes hubs have less than 16 ports */
711 dev->route = parent->route +
712 (port1 << ((parent->level - 1)*4));
714 dev->route = parent->route +
715 (15 << ((parent->level - 1)*4));
718 dev->dev.parent = &parent->dev;
719 dev_set_name(&dev->dev, "%d-%s", bus->busnum, dev->devpath);
721 if (!parent->parent) {
722 /* device under root hub's port */
723 raw_port = usb_hcd_find_raw_port_number(usb_hcd,
726 dev->dev.of_node = usb_of_get_device_node(parent, raw_port);
728 /* hub driver sets up TT records */
731 dev->portnum = port1;
733 dev->parent = parent;
734 INIT_LIST_HEAD(&dev->filelist);
737 pm_runtime_set_autosuspend_delay(&dev->dev,
738 usb_autosuspend_delay * 1000);
739 dev->connect_time = jiffies;
740 dev->active_duration = -jiffies;
742 if (root_hub) /* Root hub always ok [and always wired] */
745 dev->authorized = !!HCD_DEV_AUTHORIZED(usb_hcd);
746 dev->wusb = usb_bus_is_wusb(bus) ? 1 : 0;
750 EXPORT_SYMBOL_GPL(usb_alloc_dev);
753 * usb_get_dev - increments the reference count of the usb device structure
754 * @dev: the device being referenced
756 * Each live reference to a device should be refcounted.
758 * Drivers for USB interfaces should normally record such references in
759 * their probe() methods, when they bind to an interface, and release
760 * them by calling usb_put_dev(), in their disconnect() methods.
762 * Return: A pointer to the device with the incremented reference counter.
764 struct usb_device *usb_get_dev(struct usb_device *dev)
767 get_device(&dev->dev);
770 EXPORT_SYMBOL_GPL(usb_get_dev);
773 * usb_put_dev - release a use of the usb device structure
774 * @dev: device that's been disconnected
776 * Must be called when a user of a device is finished with it. When the last
777 * user of the device calls this function, the memory of the device is freed.
779 void usb_put_dev(struct usb_device *dev)
782 put_device(&dev->dev);
784 EXPORT_SYMBOL_GPL(usb_put_dev);
787 * usb_get_intf - increments the reference count of the usb interface structure
788 * @intf: the interface being referenced
790 * Each live reference to a interface must be refcounted.
792 * Drivers for USB interfaces should normally record such references in
793 * their probe() methods, when they bind to an interface, and release
794 * them by calling usb_put_intf(), in their disconnect() methods.
796 * Return: A pointer to the interface with the incremented reference counter.
798 struct usb_interface *usb_get_intf(struct usb_interface *intf)
801 get_device(&intf->dev);
804 EXPORT_SYMBOL_GPL(usb_get_intf);
807 * usb_put_intf - release a use of the usb interface structure
808 * @intf: interface that's been decremented
810 * Must be called when a user of an interface is finished with it. When the
811 * last user of the interface calls this function, the memory of the interface
814 void usb_put_intf(struct usb_interface *intf)
817 put_device(&intf->dev);
819 EXPORT_SYMBOL_GPL(usb_put_intf);
821 /* USB device locking
823 * USB devices and interfaces are locked using the semaphore in their
824 * embedded struct device. The hub driver guarantees that whenever a
825 * device is connected or disconnected, drivers are called with the
826 * USB device locked as well as their particular interface.
828 * Complications arise when several devices are to be locked at the same
829 * time. Only hub-aware drivers that are part of usbcore ever have to
830 * do this; nobody else needs to worry about it. The rule for locking
833 * When locking both a device and its parent, always lock the
838 * usb_lock_device_for_reset - cautiously acquire the lock for a usb device structure
839 * @udev: device that's being locked
840 * @iface: interface bound to the driver making the request (optional)
842 * Attempts to acquire the device lock, but fails if the device is
843 * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
844 * is neither BINDING nor BOUND. Rather than sleeping to wait for the
845 * lock, the routine polls repeatedly. This is to prevent deadlock with
846 * disconnect; in some drivers (such as usb-storage) the disconnect()
847 * or suspend() method will block waiting for a device reset to complete.
849 * Return: A negative error code for failure, otherwise 0.
851 int usb_lock_device_for_reset(struct usb_device *udev,
852 const struct usb_interface *iface)
854 unsigned long jiffies_expire = jiffies + HZ;
856 if (udev->state == USB_STATE_NOTATTACHED)
858 if (udev->state == USB_STATE_SUSPENDED)
859 return -EHOSTUNREACH;
860 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
861 iface->condition == USB_INTERFACE_UNBOUND))
864 while (!usb_trylock_device(udev)) {
866 /* If we can't acquire the lock after waiting one second,
867 * we're probably deadlocked */
868 if (time_after(jiffies, jiffies_expire))
872 if (udev->state == USB_STATE_NOTATTACHED)
874 if (udev->state == USB_STATE_SUSPENDED)
875 return -EHOSTUNREACH;
876 if (iface && (iface->condition == USB_INTERFACE_UNBINDING ||
877 iface->condition == USB_INTERFACE_UNBOUND))
882 EXPORT_SYMBOL_GPL(usb_lock_device_for_reset);
885 * usb_get_current_frame_number - return current bus frame number
886 * @dev: the device whose bus is being queried
888 * Return: The current frame number for the USB host controller used
889 * with the given USB device. This can be used when scheduling
890 * isochronous requests.
892 * Note: Different kinds of host controller have different "scheduling
893 * horizons". While one type might support scheduling only 32 frames
894 * into the future, others could support scheduling up to 1024 frames
898 int usb_get_current_frame_number(struct usb_device *dev)
900 return usb_hcd_get_frame_number(dev);
902 EXPORT_SYMBOL_GPL(usb_get_current_frame_number);
904 /*-------------------------------------------------------------------*/
906 * __usb_get_extra_descriptor() finds a descriptor of specific type in the
907 * extra field of the interface and endpoint descriptor structs.
910 int __usb_get_extra_descriptor(char *buffer, unsigned size,
911 unsigned char type, void **ptr, size_t minsize)
913 struct usb_descriptor_header *header;
915 while (size >= sizeof(struct usb_descriptor_header)) {
916 header = (struct usb_descriptor_header *)buffer;
918 if (header->bLength < 2 || header->bLength > size) {
920 "%s: bogus descriptor, type %d length %d\n",
922 header->bDescriptorType,
927 if (header->bDescriptorType == type && header->bLength >= minsize) {
932 buffer += header->bLength;
933 size -= header->bLength;
937 EXPORT_SYMBOL_GPL(__usb_get_extra_descriptor);
940 * usb_alloc_coherent - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
941 * @dev: device the buffer will be used with
942 * @size: requested buffer size
943 * @mem_flags: affect whether allocation may block
944 * @dma: used to return DMA address of buffer
946 * Return: Either null (indicating no buffer could be allocated), or the
947 * cpu-space pointer to a buffer that may be used to perform DMA to the
948 * specified device. Such cpu-space buffers are returned along with the DMA
949 * address (through the pointer provided).
952 * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
953 * to avoid behaviors like using "DMA bounce buffers", or thrashing IOMMU
954 * hardware during URB completion/resubmit. The implementation varies between
955 * platforms, depending on details of how DMA will work to this device.
956 * Using these buffers also eliminates cacheline sharing problems on
957 * architectures where CPU caches are not DMA-coherent. On systems without
958 * bus-snooping caches, these buffers are uncached.
960 * When the buffer is no longer used, free it with usb_free_coherent().
962 void *usb_alloc_coherent(struct usb_device *dev, size_t size, gfp_t mem_flags,
965 if (!dev || !dev->bus)
967 return hcd_buffer_alloc(dev->bus, size, mem_flags, dma);
969 EXPORT_SYMBOL_GPL(usb_alloc_coherent);
972 * usb_free_coherent - free memory allocated with usb_alloc_coherent()
973 * @dev: device the buffer was used with
974 * @size: requested buffer size
975 * @addr: CPU address of buffer
976 * @dma: DMA address of buffer
978 * This reclaims an I/O buffer, letting it be reused. The memory must have
979 * been allocated using usb_alloc_coherent(), and the parameters must match
980 * those provided in that allocation request.
982 void usb_free_coherent(struct usb_device *dev, size_t size, void *addr,
985 if (!dev || !dev->bus)
989 hcd_buffer_free(dev->bus, size, addr, dma);
991 EXPORT_SYMBOL_GPL(usb_free_coherent);
994 * usb_buffer_map - create DMA mapping(s) for an urb
995 * @urb: urb whose transfer_buffer/setup_packet will be mapped
997 * URB_NO_TRANSFER_DMA_MAP is added to urb->transfer_flags if the operation
998 * succeeds. If the device is connected to this system through a non-DMA
999 * controller, this operation always succeeds.
1001 * This call would normally be used for an urb which is reused, perhaps
1002 * as the target of a large periodic transfer, with usb_buffer_dmasync()
1003 * calls to synchronize memory and dma state.
1005 * Reverse the effect of this call with usb_buffer_unmap().
1007 * Return: Either %NULL (indicating no buffer could be mapped), or @urb.
1011 struct urb *usb_buffer_map(struct urb *urb)
1013 struct usb_bus *bus;
1014 struct device *controller;
1018 || !(bus = urb->dev->bus)
1019 || !(controller = bus->sysdev))
1022 if (controller->dma_mask) {
1023 urb->transfer_dma = dma_map_single(controller,
1024 urb->transfer_buffer, urb->transfer_buffer_length,
1025 usb_pipein(urb->pipe)
1026 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
1027 /* FIXME generic api broken like pci, can't report errors */
1028 /* if (urb->transfer_dma == DMA_ADDR_INVALID) return 0; */
1030 urb->transfer_dma = ~0;
1031 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
1034 EXPORT_SYMBOL_GPL(usb_buffer_map);
1037 /* XXX DISABLED, no users currently. If you wish to re-enable this
1038 * XXX please determine whether the sync is to transfer ownership of
1039 * XXX the buffer from device to cpu or vice verse, and thusly use the
1040 * XXX appropriate _for_{cpu,device}() method. -DaveM
1045 * usb_buffer_dmasync - synchronize DMA and CPU view of buffer(s)
1046 * @urb: urb whose transfer_buffer/setup_packet will be synchronized
1048 void usb_buffer_dmasync(struct urb *urb)
1050 struct usb_bus *bus;
1051 struct device *controller;
1054 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
1056 || !(bus = urb->dev->bus)
1057 || !(controller = bus->sysdev))
1060 if (controller->dma_mask) {
1061 dma_sync_single_for_cpu(controller,
1062 urb->transfer_dma, urb->transfer_buffer_length,
1063 usb_pipein(urb->pipe)
1064 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
1065 if (usb_pipecontrol(urb->pipe))
1066 dma_sync_single_for_cpu(controller,
1068 sizeof(struct usb_ctrlrequest),
1072 EXPORT_SYMBOL_GPL(usb_buffer_dmasync);
1076 * usb_buffer_unmap - free DMA mapping(s) for an urb
1077 * @urb: urb whose transfer_buffer will be unmapped
1079 * Reverses the effect of usb_buffer_map().
1082 void usb_buffer_unmap(struct urb *urb)
1084 struct usb_bus *bus;
1085 struct device *controller;
1088 || !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
1090 || !(bus = urb->dev->bus)
1091 || !(controller = bus->sysdev))
1094 if (controller->dma_mask) {
1095 dma_unmap_single(controller,
1096 urb->transfer_dma, urb->transfer_buffer_length,
1097 usb_pipein(urb->pipe)
1098 ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
1100 urb->transfer_flags &= ~URB_NO_TRANSFER_DMA_MAP;
1102 EXPORT_SYMBOL_GPL(usb_buffer_unmap);
1107 * usb_buffer_map_sg - create scatterlist DMA mapping(s) for an endpoint
1108 * @dev: device to which the scatterlist will be mapped
1109 * @is_in: mapping transfer direction
1110 * @sg: the scatterlist to map
1111 * @nents: the number of entries in the scatterlist
1113 * Return: Either < 0 (indicating no buffers could be mapped), or the
1114 * number of DMA mapping array entries in the scatterlist.
1117 * The caller is responsible for placing the resulting DMA addresses from
1118 * the scatterlist into URB transfer buffer pointers, and for setting the
1119 * URB_NO_TRANSFER_DMA_MAP transfer flag in each of those URBs.
1121 * Top I/O rates come from queuing URBs, instead of waiting for each one
1122 * to complete before starting the next I/O. This is particularly easy
1123 * to do with scatterlists. Just allocate and submit one URB for each DMA
1124 * mapping entry returned, stopping on the first error or when all succeed.
1125 * Better yet, use the usb_sg_*() calls, which do that (and more) for you.
1127 * This call would normally be used when translating scatterlist requests,
1128 * rather than usb_buffer_map(), since on some hardware (with IOMMUs) it
1129 * may be able to coalesce mappings for improved I/O efficiency.
1131 * Reverse the effect of this call with usb_buffer_unmap_sg().
1133 int usb_buffer_map_sg(const struct usb_device *dev, int is_in,
1134 struct scatterlist *sg, int nents)
1136 struct usb_bus *bus;
1137 struct device *controller;
1140 || !(bus = dev->bus)
1141 || !(controller = bus->sysdev)
1142 || !controller->dma_mask)
1145 /* FIXME generic api broken like pci, can't report errors */
1146 return dma_map_sg(controller, sg, nents,
1147 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE) ? : -ENOMEM;
1149 EXPORT_SYMBOL_GPL(usb_buffer_map_sg);
1152 /* XXX DISABLED, no users currently. If you wish to re-enable this
1153 * XXX please determine whether the sync is to transfer ownership of
1154 * XXX the buffer from device to cpu or vice verse, and thusly use the
1155 * XXX appropriate _for_{cpu,device}() method. -DaveM
1160 * usb_buffer_dmasync_sg - synchronize DMA and CPU view of scatterlist buffer(s)
1161 * @dev: device to which the scatterlist will be mapped
1162 * @is_in: mapping transfer direction
1163 * @sg: the scatterlist to synchronize
1164 * @n_hw_ents: the positive return value from usb_buffer_map_sg
1166 * Use this when you are re-using a scatterlist's data buffers for
1167 * another USB request.
1169 void usb_buffer_dmasync_sg(const struct usb_device *dev, int is_in,
1170 struct scatterlist *sg, int n_hw_ents)
1172 struct usb_bus *bus;
1173 struct device *controller;
1176 || !(bus = dev->bus)
1177 || !(controller = bus->sysdev)
1178 || !controller->dma_mask)
1181 dma_sync_sg_for_cpu(controller, sg, n_hw_ents,
1182 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
1184 EXPORT_SYMBOL_GPL(usb_buffer_dmasync_sg);
1189 * usb_buffer_unmap_sg - free DMA mapping(s) for a scatterlist
1190 * @dev: device to which the scatterlist will be mapped
1191 * @is_in: mapping transfer direction
1192 * @sg: the scatterlist to unmap
1193 * @n_hw_ents: the positive return value from usb_buffer_map_sg
1195 * Reverses the effect of usb_buffer_map_sg().
1197 void usb_buffer_unmap_sg(const struct usb_device *dev, int is_in,
1198 struct scatterlist *sg, int n_hw_ents)
1200 struct usb_bus *bus;
1201 struct device *controller;
1204 || !(bus = dev->bus)
1205 || !(controller = bus->sysdev)
1206 || !controller->dma_mask)
1209 dma_unmap_sg(controller, sg, n_hw_ents,
1210 is_in ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
1212 EXPORT_SYMBOL_GPL(usb_buffer_unmap_sg);
1216 * Notifications of device and interface registration
1218 static int usb_bus_notify(struct notifier_block *nb, unsigned long action,
1221 struct device *dev = data;
1224 case BUS_NOTIFY_ADD_DEVICE:
1225 if (dev->type == &usb_device_type)
1226 (void) usb_create_sysfs_dev_files(to_usb_device(dev));
1227 else if (dev->type == &usb_if_device_type)
1228 usb_create_sysfs_intf_files(to_usb_interface(dev));
1231 case BUS_NOTIFY_DEL_DEVICE:
1232 if (dev->type == &usb_device_type)
1233 usb_remove_sysfs_dev_files(to_usb_device(dev));
1234 else if (dev->type == &usb_if_device_type)
1235 usb_remove_sysfs_intf_files(to_usb_interface(dev));
1241 static struct notifier_block usb_bus_nb = {
1242 .notifier_call = usb_bus_notify,
1245 struct dentry *usb_debug_root;
1246 EXPORT_SYMBOL_GPL(usb_debug_root);
1248 static void usb_debugfs_init(void)
1250 usb_debug_root = debugfs_create_dir("usb", NULL);
1251 debugfs_create_file("devices", 0444, usb_debug_root, NULL,
1252 &usbfs_devices_fops);
1255 static void usb_debugfs_cleanup(void)
1257 debugfs_remove_recursive(usb_debug_root);
1263 static int __init usb_init(void)
1266 if (usb_disabled()) {
1267 pr_info("%s: USB support disabled\n", usbcore_name);
1270 usb_init_pool_max();
1274 usb_acpi_register();
1275 retval = bus_register(&usb_bus_type);
1277 goto bus_register_failed;
1278 retval = bus_register_notifier(&usb_bus_type, &usb_bus_nb);
1280 goto bus_notifier_failed;
1281 retval = usb_major_init();
1283 goto major_init_failed;
1284 retval = usb_register(&usbfs_driver);
1286 goto driver_register_failed;
1287 retval = usb_devio_init();
1289 goto usb_devio_init_failed;
1290 retval = usb_hub_init();
1292 goto hub_init_failed;
1293 retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
1299 usb_devio_cleanup();
1300 usb_devio_init_failed:
1301 usb_deregister(&usbfs_driver);
1302 driver_register_failed:
1303 usb_major_cleanup();
1305 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1306 bus_notifier_failed:
1307 bus_unregister(&usb_bus_type);
1308 bus_register_failed:
1309 usb_acpi_unregister();
1310 usb_debugfs_cleanup();
1318 static void __exit usb_exit(void)
1320 /* This will matter if shutdown/reboot does exitcalls. */
1324 usb_release_quirk_list();
1325 usb_deregister_device_driver(&usb_generic_driver);
1326 usb_major_cleanup();
1327 usb_deregister(&usbfs_driver);
1328 usb_devio_cleanup();
1330 bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
1331 bus_unregister(&usb_bus_type);
1332 usb_acpi_unregister();
1333 usb_debugfs_cleanup();
1334 idr_destroy(&usb_bus_idr);
1337 subsys_initcall(usb_init);
1338 module_exit(usb_exit);
1339 MODULE_LICENSE("GPL");