// SPDX-License-Identifier: GPL-2.0 /* * drivers/usb/core/usb.c * * (C) Copyright Linus Torvalds 1999 * (C) Copyright Johannes Erdfelt 1999-2001 * (C) Copyright Andreas Gal 1999 * (C) Copyright Gregory P. Smith 1999 * (C) Copyright Deti Fliegl 1999 (new USB architecture) * (C) Copyright Randy Dunlap 2000 * (C) Copyright David Brownell 2000-2004 * (C) Copyright Yggdrasil Computing, Inc. 2000 * (usb_device_id matching changes by Adam J. Richter) * (C) Copyright Greg Kroah-Hartman 2002-2003 * * Released under the GPLv2 only. * * NOTE! This is not actually a driver at all, rather this is * just a collection of helper routines that implement the * generic USB things that the real drivers can use.. * * Think of this as a "USB library" rather than anything else, * with no callbacks. Callbacks are evil. */ #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/of.h> #include <linux/string.h> #include <linux/bitops.h> #include <linux/slab.h> #include <linux/kmod.h> #include <linux/init.h> #include <linux/spinlock.h> #include <linux/errno.h> #include <linux/usb.h> #include <linux/usb/hcd.h> #include <linux/mutex.h> #include <linux/workqueue.h> #include <linux/debugfs.h> #include <linux/usb/of.h> #include <asm/io.h> #include <linux/scatterlist.h> #include <linux/mm.h> #include <linux/dma-mapping.h> #include "hub.h" const char *usbcore_name = …; static bool nousb; /* Disable USB when built into kernel image */ module_param(nousb, bool, 0444); /* * for external read access to <nousb> */ int usb_disabled(void) { … } EXPORT_SYMBOL_GPL(…); #ifdef CONFIG_PM /* Default delay value, in seconds */ static int usb_autosuspend_delay = …; module_param_named(autosuspend, usb_autosuspend_delay, int, 0644); MODULE_PARM_DESC(…) …; #else #define usb_autosuspend_delay … #endif static bool match_endpoint(struct usb_endpoint_descriptor *epd, struct usb_endpoint_descriptor **bulk_in, struct usb_endpoint_descriptor **bulk_out, struct usb_endpoint_descriptor **int_in, struct usb_endpoint_descriptor **int_out) { … } /** * usb_find_common_endpoints() -- look up common endpoint descriptors * @alt: alternate setting to search * @bulk_in: pointer to descriptor pointer, or NULL * @bulk_out: pointer to descriptor pointer, or NULL * @int_in: pointer to descriptor pointer, or NULL * @int_out: pointer to descriptor pointer, or NULL * * Search the alternate setting's endpoint descriptors for the first bulk-in, * bulk-out, interrupt-in and interrupt-out endpoints and return them in the * provided pointers (unless they are NULL). * * If a requested endpoint is not found, the corresponding pointer is set to * NULL. * * Return: Zero if all requested descriptors were found, or -ENXIO otherwise. */ int usb_find_common_endpoints(struct usb_host_interface *alt, struct usb_endpoint_descriptor **bulk_in, struct usb_endpoint_descriptor **bulk_out, struct usb_endpoint_descriptor **int_in, struct usb_endpoint_descriptor **int_out) { … } EXPORT_SYMBOL_GPL(…); /** * usb_find_common_endpoints_reverse() -- look up common endpoint descriptors * @alt: alternate setting to search * @bulk_in: pointer to descriptor pointer, or NULL * @bulk_out: pointer to descriptor pointer, or NULL * @int_in: pointer to descriptor pointer, or NULL * @int_out: pointer to descriptor pointer, or NULL * * Search the alternate setting's endpoint descriptors for the last bulk-in, * bulk-out, interrupt-in and interrupt-out endpoints and return them in the * provided pointers (unless they are NULL). * * If a requested endpoint is not found, the corresponding pointer is set to * NULL. * * Return: Zero if all requested descriptors were found, or -ENXIO otherwise. */ int usb_find_common_endpoints_reverse(struct usb_host_interface *alt, struct usb_endpoint_descriptor **bulk_in, struct usb_endpoint_descriptor **bulk_out, struct usb_endpoint_descriptor **int_in, struct usb_endpoint_descriptor **int_out) { … } EXPORT_SYMBOL_GPL(…); /** * usb_find_endpoint() - Given an endpoint address, search for the endpoint's * usb_host_endpoint structure in an interface's current altsetting. * @intf: the interface whose current altsetting should be searched * @ep_addr: the endpoint address (number and direction) to find * * Search the altsetting's list of endpoints for one with the specified address. * * Return: Pointer to the usb_host_endpoint if found, %NULL otherwise. */ static const struct usb_host_endpoint *usb_find_endpoint( const struct usb_interface *intf, unsigned int ep_addr) { … } /** * usb_check_bulk_endpoints - Check whether an interface's current altsetting * contains a set of bulk endpoints with the given addresses. * @intf: the interface whose current altsetting should be searched * @ep_addrs: 0-terminated array of the endpoint addresses (number and * direction) to look for * * Search for endpoints with the specified addresses and check their types. * * Return: %true if all the endpoints are found and are bulk, %false otherwise. */ bool usb_check_bulk_endpoints( const struct usb_interface *intf, const u8 *ep_addrs) { … } EXPORT_SYMBOL_GPL(…); /** * usb_check_int_endpoints - Check whether an interface's current altsetting * contains a set of interrupt endpoints with the given addresses. * @intf: the interface whose current altsetting should be searched * @ep_addrs: 0-terminated array of the endpoint addresses (number and * direction) to look for * * Search for endpoints with the specified addresses and check their types. * * Return: %true if all the endpoints are found and are interrupt, * %false otherwise. */ bool usb_check_int_endpoints( const struct usb_interface *intf, const u8 *ep_addrs) { … } EXPORT_SYMBOL_GPL(…); /** * usb_find_alt_setting() - Given a configuration, find the alternate setting * for the given interface. * @config: the configuration to search (not necessarily the current config). * @iface_num: interface number to search in * @alt_num: alternate interface setting number to search for. * * Search the configuration's interface cache for the given alt setting. * * Return: The alternate setting, if found. %NULL otherwise. */ struct usb_host_interface *usb_find_alt_setting( struct usb_host_config *config, unsigned int iface_num, unsigned int alt_num) { … } EXPORT_SYMBOL_GPL(…); /** * usb_ifnum_to_if - get the interface object with a given interface number * @dev: the device whose current configuration is considered * @ifnum: the desired interface * * This walks the device descriptor for the currently active configuration * to find the interface object with the particular interface number. * * Note that configuration descriptors are not required to assign interface * numbers sequentially, so that it would be incorrect to assume that * the first interface in that descriptor corresponds to interface zero. * This routine helps device drivers avoid such mistakes. * However, you should make sure that you do the right thing with any * alternate settings available for this interfaces. * * Don't call this function unless you are bound to one of the interfaces * on this device or you have locked the device! * * Return: A pointer to the interface that has @ifnum as interface number, * if found. %NULL otherwise. */ struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev, unsigned ifnum) { … } EXPORT_SYMBOL_GPL(…); /** * usb_altnum_to_altsetting - get the altsetting structure with a given alternate setting number. * @intf: the interface containing the altsetting in question * @altnum: the desired alternate setting number * * This searches the altsetting array of the specified interface for * an entry with the correct bAlternateSetting value. * * Note that altsettings need not be stored sequentially by number, so * it would be incorrect to assume that the first altsetting entry in * the array corresponds to altsetting zero. This routine helps device * drivers avoid such mistakes. * * Don't call this function unless you are bound to the intf interface * or you have locked the device! * * Return: A pointer to the entry of the altsetting array of @intf that * has @altnum as the alternate setting number. %NULL if not found. */ struct usb_host_interface *usb_altnum_to_altsetting( const struct usb_interface *intf, unsigned int altnum) { … } EXPORT_SYMBOL_GPL(…); struct find_interface_arg { … }; static int __find_interface(struct device *dev, const void *data) { … } /** * usb_find_interface - find usb_interface pointer for driver and device * @drv: the driver whose current configuration is considered * @minor: the minor number of the desired device * * This walks the bus device list and returns a pointer to the interface * with the matching minor and driver. Note, this only works for devices * that share the USB major number. * * Return: A pointer to the interface with the matching major and @minor. */ struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor) { … } EXPORT_SYMBOL_GPL(…); struct each_dev_arg { … }; static int __each_dev(struct device *dev, void *data) { … } /** * usb_for_each_dev - iterate over all USB devices in the system * @data: data pointer that will be handed to the callback function * @fn: callback function to be called for each USB device * * Iterate over all USB devices and call @fn for each, passing it @data. If it * returns anything other than 0, we break the iteration prematurely and return * that value. */ int usb_for_each_dev(void *data, int (*fn)(struct usb_device *, void *)) { … } EXPORT_SYMBOL_GPL(…); /** * usb_release_dev - free a usb device structure when all users of it are finished. * @dev: device that's been disconnected * * Will be called only by the device core when all users of this usb device are * done. */ static void usb_release_dev(struct device *dev) { … } static int usb_dev_uevent(const struct device *dev, struct kobj_uevent_env *env) { … } #ifdef CONFIG_PM /* USB device Power-Management thunks. * There's no need to distinguish here between quiescing a USB device * and powering it down; the generic_suspend() routine takes care of * it by skipping the usb_port_suspend() call for a quiesce. And for * USB interfaces there's no difference at all. */ static int usb_dev_prepare(struct device *dev) { … } static void usb_dev_complete(struct device *dev) { … } static int usb_dev_suspend(struct device *dev) { … } static int usb_dev_resume(struct device *dev) { … } static int usb_dev_freeze(struct device *dev) { … } static int usb_dev_thaw(struct device *dev) { … } static int usb_dev_poweroff(struct device *dev) { … } static int usb_dev_restore(struct device *dev) { … } static const struct dev_pm_ops usb_device_pm_ops = …; #endif /* CONFIG_PM */ static char *usb_devnode(const struct device *dev, umode_t *mode, kuid_t *uid, kgid_t *gid) { … } const struct device_type usb_device_type = …; static bool usb_dev_authorized(struct usb_device *dev, struct usb_hcd *hcd) { … } /** * usb_alloc_dev - usb device constructor (usbcore-internal) * @parent: hub to which device is connected; null to allocate a root hub * @bus: bus used to access the device * @port1: one-based index of port; ignored for root hubs * * Context: task context, might sleep. * * Only hub drivers (including virtual root hub drivers for host * controllers) should ever call this. * * This call may not be used in a non-sleeping context. * * Return: On success, a pointer to the allocated usb device. %NULL on * failure. */ struct usb_device *usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port1) { … } EXPORT_SYMBOL_GPL(…); /** * usb_get_dev - increments the reference count of the usb device structure * @dev: the device being referenced * * Each live reference to a device should be refcounted. * * Drivers for USB interfaces should normally record such references in * their probe() methods, when they bind to an interface, and release * them by calling usb_put_dev(), in their disconnect() methods. * However, if a driver does not access the usb_device structure after * its disconnect() method returns then refcounting is not necessary, * because the USB core guarantees that a usb_device will not be * deallocated until after all of its interface drivers have been unbound. * * Return: A pointer to the device with the incremented reference counter. */ struct usb_device *usb_get_dev(struct usb_device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * usb_put_dev - release a use of the usb device structure * @dev: device that's been disconnected * * Must be called when a user of a device is finished with it. When the last * user of the device calls this function, the memory of the device is freed. */ void usb_put_dev(struct usb_device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * usb_get_intf - increments the reference count of the usb interface structure * @intf: the interface being referenced * * Each live reference to a interface must be refcounted. * * Drivers for USB interfaces should normally record such references in * their probe() methods, when they bind to an interface, and release * them by calling usb_put_intf(), in their disconnect() methods. * However, if a driver does not access the usb_interface structure after * its disconnect() method returns then refcounting is not necessary, * because the USB core guarantees that a usb_interface will not be * deallocated until after its driver has been unbound. * * Return: A pointer to the interface with the incremented reference counter. */ struct usb_interface *usb_get_intf(struct usb_interface *intf) { … } EXPORT_SYMBOL_GPL(…); /** * usb_put_intf - release a use of the usb interface structure * @intf: interface that's been decremented * * Must be called when a user of an interface is finished with it. When the * last user of the interface calls this function, the memory of the interface * is freed. */ void usb_put_intf(struct usb_interface *intf) { … } EXPORT_SYMBOL_GPL(…); /** * usb_intf_get_dma_device - acquire a reference on the usb interface's DMA endpoint * @intf: the usb interface * * While a USB device cannot perform DMA operations by itself, many USB * controllers can. A call to usb_intf_get_dma_device() returns the DMA endpoint * for the given USB interface, if any. The returned device structure must be * released with put_device(). * * See also usb_get_dma_device(). * * Returns: A reference to the usb interface's DMA endpoint; or NULL if none * exists. */ struct device *usb_intf_get_dma_device(struct usb_interface *intf) { … } EXPORT_SYMBOL_GPL(…); /* USB device locking * * USB devices and interfaces are locked using the semaphore in their * embedded struct device. The hub driver guarantees that whenever a * device is connected or disconnected, drivers are called with the * USB device locked as well as their particular interface. * * Complications arise when several devices are to be locked at the same * time. Only hub-aware drivers that are part of usbcore ever have to * do this; nobody else needs to worry about it. The rule for locking * is simple: * * When locking both a device and its parent, always lock the * parent first. */ /** * usb_lock_device_for_reset - cautiously acquire the lock for a usb device structure * @udev: device that's being locked * @iface: interface bound to the driver making the request (optional) * * Attempts to acquire the device lock, but fails if the device is * NOTATTACHED or SUSPENDED, or if iface is specified and the interface * is neither BINDING nor BOUND. Rather than sleeping to wait for the * lock, the routine polls repeatedly. This is to prevent deadlock with * disconnect; in some drivers (such as usb-storage) the disconnect() * or suspend() method will block waiting for a device reset to complete. * * Return: A negative error code for failure, otherwise 0. */ int usb_lock_device_for_reset(struct usb_device *udev, const struct usb_interface *iface) { … } EXPORT_SYMBOL_GPL(…); /** * usb_get_current_frame_number - return current bus frame number * @dev: the device whose bus is being queried * * Return: The current frame number for the USB host controller used * with the given USB device. This can be used when scheduling * isochronous requests. * * Note: Different kinds of host controller have different "scheduling * horizons". While one type might support scheduling only 32 frames * into the future, others could support scheduling up to 1024 frames * into the future. * */ int usb_get_current_frame_number(struct usb_device *dev) { … } EXPORT_SYMBOL_GPL(…); /*-------------------------------------------------------------------*/ /* * __usb_get_extra_descriptor() finds a descriptor of specific type in the * extra field of the interface and endpoint descriptor structs. */ int __usb_get_extra_descriptor(char *buffer, unsigned size, unsigned char type, void **ptr, size_t minsize) { … } EXPORT_SYMBOL_GPL(…); /** * usb_alloc_coherent - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP * @dev: device the buffer will be used with * @size: requested buffer size * @mem_flags: affect whether allocation may block * @dma: used to return DMA address of buffer * * Return: Either null (indicating no buffer could be allocated), or the * cpu-space pointer to a buffer that may be used to perform DMA to the * specified device. Such cpu-space buffers are returned along with the DMA * address (through the pointer provided). * * Note: * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags * to avoid behaviors like using "DMA bounce buffers", or thrashing IOMMU * hardware during URB completion/resubmit. The implementation varies between * platforms, depending on details of how DMA will work to this device. * Using these buffers also eliminates cacheline sharing problems on * architectures where CPU caches are not DMA-coherent. On systems without * bus-snooping caches, these buffers are uncached. * * When the buffer is no longer used, free it with usb_free_coherent(). */ void *usb_alloc_coherent(struct usb_device *dev, size_t size, gfp_t mem_flags, dma_addr_t *dma) { … } EXPORT_SYMBOL_GPL(…); /** * usb_free_coherent - free memory allocated with usb_alloc_coherent() * @dev: device the buffer was used with * @size: requested buffer size * @addr: CPU address of buffer * @dma: DMA address of buffer * * This reclaims an I/O buffer, letting it be reused. The memory must have * been allocated using usb_alloc_coherent(), and the parameters must match * those provided in that allocation request. */ void usb_free_coherent(struct usb_device *dev, size_t size, void *addr, dma_addr_t dma) { … } EXPORT_SYMBOL_GPL(…); /* * Notifications of device and interface registration */ static int usb_bus_notify(struct notifier_block *nb, unsigned long action, void *data) { … } static struct notifier_block usb_bus_nb = …; static void usb_debugfs_init(void) { … } static void usb_debugfs_cleanup(void) { … } /* * Init */ static int __init usb_init(void) { … } /* * Cleanup */ static void __exit usb_exit(void) { … } subsys_initcall(usb_init); module_exit(usb_exit); MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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