linux/drivers/usb/gadget/udc/core.c

// SPDX-License-Identifier: GPL-2.0
/*
 * udc.c - Core UDC Framework
 *
 * Copyright (C) 2010 Texas Instruments
 * Author: Felipe Balbi <[email protected]>
 */

#define pr_fmt(fmt)

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/idr.h>
#include <linux/err.h>
#include <linux/dma-mapping.h>
#include <linux/sched/task_stack.h>
#include <linux/workqueue.h>

#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
#include <linux/usb.h>

#include "trace.h"

static DEFINE_IDA(gadget_id_numbers);

static const struct bus_type gadget_bus_type;

/**
 * struct usb_udc - describes one usb device controller
 * @driver: the gadget driver pointer. For use by the class code
 * @dev: the child device to the actual controller
 * @gadget: the gadget. For use by the class code
 * @list: for use by the udc class driver
 * @vbus: for udcs who care about vbus status, this value is real vbus status;
 * for udcs who do not care about vbus status, this value is always true
 * @started: the UDC's started state. True if the UDC had started.
 * @allow_connect: Indicates whether UDC is allowed to be pulled up.
 * Set/cleared by gadget_(un)bind_driver() after gadget driver is bound or
 * unbound.
 * @vbus_work: work routine to handle VBUS status change notifications.
 * @connect_lock: protects udc->started, gadget->connect,
 * gadget->allow_connect and gadget->deactivate. The routines
 * usb_gadget_connect_locked(), usb_gadget_disconnect_locked(),
 * usb_udc_connect_control_locked(), usb_gadget_udc_start_locked() and
 * usb_gadget_udc_stop_locked() are called with this lock held.
 *
 * This represents the internal data structure which is used by the UDC-class
 * to hold information about udc driver and gadget together.
 */
struct usb_udc {};

static const struct class udc_class;
static LIST_HEAD(udc_list);

/* Protects udc_list, udc->driver, driver->is_bound, and related calls */
static DEFINE_MUTEX(udc_lock);

/* ------------------------------------------------------------------------- */

/**
 * usb_ep_set_maxpacket_limit - set maximum packet size limit for endpoint
 * @ep:the endpoint being configured
 * @maxpacket_limit:value of maximum packet size limit
 *
 * This function should be used only in UDC drivers to initialize endpoint
 * (usually in probe function).
 */
void usb_ep_set_maxpacket_limit(struct usb_ep *ep,
					      unsigned maxpacket_limit)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_ep_enable - configure endpoint, making it usable
 * @ep:the endpoint being configured.  may not be the endpoint named "ep0".
 *	drivers discover endpoints through the ep_list of a usb_gadget.
 *
 * When configurations are set, or when interface settings change, the driver
 * will enable or disable the relevant endpoints.  while it is enabled, an
 * endpoint may be used for i/o until the driver receives a disconnect() from
 * the host or until the endpoint is disabled.
 *
 * the ep0 implementation (which calls this routine) must ensure that the
 * hardware capabilities of each endpoint match the descriptor provided
 * for it.  for example, an endpoint named "ep2in-bulk" would be usable
 * for interrupt transfers as well as bulk, but it likely couldn't be used
 * for iso transfers or for endpoint 14.  some endpoints are fully
 * configurable, with more generic names like "ep-a".  (remember that for
 * USB, "in" means "towards the USB host".)
 *
 * This routine may be called in an atomic (interrupt) context.
 *
 * returns zero, or a negative error code.
 */
int usb_ep_enable(struct usb_ep *ep)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_ep_disable - endpoint is no longer usable
 * @ep:the endpoint being unconfigured.  may not be the endpoint named "ep0".
 *
 * no other task may be using this endpoint when this is called.
 * any pending and uncompleted requests will complete with status
 * indicating disconnect (-ESHUTDOWN) before this call returns.
 * gadget drivers must call usb_ep_enable() again before queueing
 * requests to the endpoint.
 *
 * This routine may be called in an atomic (interrupt) context.
 *
 * returns zero, or a negative error code.
 */
int usb_ep_disable(struct usb_ep *ep)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_ep_alloc_request - allocate a request object to use with this endpoint
 * @ep:the endpoint to be used with with the request
 * @gfp_flags:GFP_* flags to use
 *
 * Request objects must be allocated with this call, since they normally
 * need controller-specific setup and may even need endpoint-specific
 * resources such as allocation of DMA descriptors.
 * Requests may be submitted with usb_ep_queue(), and receive a single
 * completion callback.  Free requests with usb_ep_free_request(), when
 * they are no longer needed.
 *
 * Returns the request, or null if one could not be allocated.
 */
struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,
						       gfp_t gfp_flags)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_ep_free_request - frees a request object
 * @ep:the endpoint associated with the request
 * @req:the request being freed
 *
 * Reverses the effect of usb_ep_alloc_request().
 * Caller guarantees the request is not queued, and that it will
 * no longer be requeued (or otherwise used).
 */
void usb_ep_free_request(struct usb_ep *ep,
				       struct usb_request *req)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_ep_queue - queues (submits) an I/O request to an endpoint.
 * @ep:the endpoint associated with the request
 * @req:the request being submitted
 * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
 *	pre-allocate all necessary memory with the request.
 *
 * This tells the device controller to perform the specified request through
 * that endpoint (reading or writing a buffer).  When the request completes,
 * including being canceled by usb_ep_dequeue(), the request's completion
 * routine is called to return the request to the driver.  Any endpoint
 * (except control endpoints like ep0) may have more than one transfer
 * request queued; they complete in FIFO order.  Once a gadget driver
 * submits a request, that request may not be examined or modified until it
 * is given back to that driver through the completion callback.
 *
 * Each request is turned into one or more packets.  The controller driver
 * never merges adjacent requests into the same packet.  OUT transfers
 * will sometimes use data that's already buffered in the hardware.
 * Drivers can rely on the fact that the first byte of the request's buffer
 * always corresponds to the first byte of some USB packet, for both
 * IN and OUT transfers.
 *
 * Bulk endpoints can queue any amount of data; the transfer is packetized
 * automatically.  The last packet will be short if the request doesn't fill it
 * out completely.  Zero length packets (ZLPs) should be avoided in portable
 * protocols since not all usb hardware can successfully handle zero length
 * packets.  (ZLPs may be explicitly written, and may be implicitly written if
 * the request 'zero' flag is set.)  Bulk endpoints may also be used
 * for interrupt transfers; but the reverse is not true, and some endpoints
 * won't support every interrupt transfer.  (Such as 768 byte packets.)
 *
 * Interrupt-only endpoints are less functional than bulk endpoints, for
 * example by not supporting queueing or not handling buffers that are
 * larger than the endpoint's maxpacket size.  They may also treat data
 * toggle differently.
 *
 * Control endpoints ... after getting a setup() callback, the driver queues
 * one response (even if it would be zero length).  That enables the
 * status ack, after transferring data as specified in the response.  Setup
 * functions may return negative error codes to generate protocol stalls.
 * (Note that some USB device controllers disallow protocol stall responses
 * in some cases.)  When control responses are deferred (the response is
 * written after the setup callback returns), then usb_ep_set_halt() may be
 * used on ep0 to trigger protocol stalls.  Depending on the controller,
 * it may not be possible to trigger a status-stage protocol stall when the
 * data stage is over, that is, from within the response's completion
 * routine.
 *
 * For periodic endpoints, like interrupt or isochronous ones, the usb host
 * arranges to poll once per interval, and the gadget driver usually will
 * have queued some data to transfer at that time.
 *
 * Note that @req's ->complete() callback must never be called from
 * within usb_ep_queue() as that can create deadlock situations.
 *
 * This routine may be called in interrupt context.
 *
 * Returns zero, or a negative error code.  Endpoints that are not enabled
 * report errors; errors will also be
 * reported when the usb peripheral is disconnected.
 *
 * If and only if @req is successfully queued (the return value is zero),
 * @req->complete() will be called exactly once, when the Gadget core and
 * UDC are finished with the request.  When the completion function is called,
 * control of the request is returned to the device driver which submitted it.
 * The completion handler may then immediately free or reuse @req.
 */
int usb_ep_queue(struct usb_ep *ep,
			       struct usb_request *req, gfp_t gfp_flags)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
 * @ep:the endpoint associated with the request
 * @req:the request being canceled
 *
 * If the request is still active on the endpoint, it is dequeued and
 * eventually its completion routine is called (with status -ECONNRESET);
 * else a negative error code is returned.  This routine is asynchronous,
 * that is, it may return before the completion routine runs.
 *
 * Note that some hardware can't clear out write fifos (to unlink the request
 * at the head of the queue) except as part of disconnecting from usb. Such
 * restrictions prevent drivers from supporting configuration changes,
 * even to configuration zero (a "chapter 9" requirement).
 *
 * This routine may be called in interrupt context.
 */
int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_ep_set_halt - sets the endpoint halt feature.
 * @ep: the non-isochronous endpoint being stalled
 *
 * Use this to stall an endpoint, perhaps as an error report.
 * Except for control endpoints,
 * the endpoint stays halted (will not stream any data) until the host
 * clears this feature; drivers may need to empty the endpoint's request
 * queue first, to make sure no inappropriate transfers happen.
 *
 * Note that while an endpoint CLEAR_FEATURE will be invisible to the
 * gadget driver, a SET_INTERFACE will not be.  To reset endpoints for the
 * current altsetting, see usb_ep_clear_halt().  When switching altsettings,
 * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.
 *
 * This routine may be called in interrupt context.
 *
 * Returns zero, or a negative error code.  On success, this call sets
 * underlying hardware state that blocks data transfers.
 * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
 * transfer requests are still queued, or if the controller hardware
 * (usually a FIFO) still holds bytes that the host hasn't collected.
 */
int usb_ep_set_halt(struct usb_ep *ep)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_ep_clear_halt - clears endpoint halt, and resets toggle
 * @ep:the bulk or interrupt endpoint being reset
 *
 * Use this when responding to the standard usb "set interface" request,
 * for endpoints that aren't reconfigured, after clearing any other state
 * in the endpoint's i/o queue.
 *
 * This routine may be called in interrupt context.
 *
 * Returns zero, or a negative error code.  On success, this call clears
 * the underlying hardware state reflecting endpoint halt and data toggle.
 * Note that some hardware can't support this request (like pxa2xx_udc),
 * and accordingly can't correctly implement interface altsettings.
 */
int usb_ep_clear_halt(struct usb_ep *ep)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_ep_set_wedge - sets the halt feature and ignores clear requests
 * @ep: the endpoint being wedged
 *
 * Use this to stall an endpoint and ignore CLEAR_FEATURE(HALT_ENDPOINT)
 * requests. If the gadget driver clears the halt status, it will
 * automatically unwedge the endpoint.
 *
 * This routine may be called in interrupt context.
 *
 * Returns zero on success, else negative errno.
 */
int usb_ep_set_wedge(struct usb_ep *ep)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_ep_fifo_status - returns number of bytes in fifo, or error
 * @ep: the endpoint whose fifo status is being checked.
 *
 * FIFO endpoints may have "unclaimed data" in them in certain cases,
 * such as after aborted transfers.  Hosts may not have collected all
 * the IN data written by the gadget driver (and reported by a request
 * completion).  The gadget driver may not have collected all the data
 * written OUT to it by the host.  Drivers that need precise handling for
 * fault reporting or recovery may need to use this call.
 *
 * This routine may be called in interrupt context.
 *
 * This returns the number of such bytes in the fifo, or a negative
 * errno if the endpoint doesn't use a FIFO or doesn't support such
 * precise handling.
 */
int usb_ep_fifo_status(struct usb_ep *ep)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_ep_fifo_flush - flushes contents of a fifo
 * @ep: the endpoint whose fifo is being flushed.
 *
 * This call may be used to flush the "unclaimed data" that may exist in
 * an endpoint fifo after abnormal transaction terminations.  The call
 * must never be used except when endpoint is not being used for any
 * protocol translation.
 *
 * This routine may be called in interrupt context.
 */
void usb_ep_fifo_flush(struct usb_ep *ep)
{}
EXPORT_SYMBOL_GPL();

/* ------------------------------------------------------------------------- */

/**
 * usb_gadget_frame_number - returns the current frame number
 * @gadget: controller that reports the frame number
 *
 * Returns the usb frame number, normally eleven bits from a SOF packet,
 * or negative errno if this device doesn't support this capability.
 */
int usb_gadget_frame_number(struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_gadget_wakeup - tries to wake up the host connected to this gadget
 * @gadget: controller used to wake up the host
 *
 * Returns zero on success, else negative error code if the hardware
 * doesn't support such attempts, or its support has not been enabled
 * by the usb host.  Drivers must return device descriptors that report
 * their ability to support this, or hosts won't enable it.
 *
 * This may also try to use SRP to wake the host and start enumeration,
 * even if OTG isn't otherwise in use.  OTG devices may also start
 * remote wakeup even when hosts don't explicitly enable it.
 */
int usb_gadget_wakeup(struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_gadget_set_remote_wakeup - configures the device remote wakeup feature.
 * @gadget:the device being configured for remote wakeup
 * @set:value to be configured.
 *
 * set to one to enable remote wakeup feature and zero to disable it.
 *
 * returns zero on success, else negative errno.
 */
int usb_gadget_set_remote_wakeup(struct usb_gadget *gadget, int set)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_gadget_set_selfpowered - sets the device selfpowered feature.
 * @gadget:the device being declared as self-powered
 *
 * this affects the device status reported by the hardware driver
 * to reflect that it now has a local power supply.
 *
 * returns zero on success, else negative errno.
 */
int usb_gadget_set_selfpowered(struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
 * @gadget:the device being declared as bus-powered
 *
 * this affects the device status reported by the hardware driver.
 * some hardware may not support bus-powered operation, in which
 * case this feature's value can never change.
 *
 * returns zero on success, else negative errno.
 */
int usb_gadget_clear_selfpowered(struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_gadget_vbus_connect - Notify controller that VBUS is powered
 * @gadget:The device which now has VBUS power.
 * Context: can sleep
 *
 * This call is used by a driver for an external transceiver (or GPIO)
 * that detects a VBUS power session starting.  Common responses include
 * resuming the controller, activating the D+ (or D-) pullup to let the
 * host detect that a USB device is attached, and starting to draw power
 * (8mA or possibly more, especially after SET_CONFIGURATION).
 *
 * Returns zero on success, else negative errno.
 */
int usb_gadget_vbus_connect(struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_gadget_vbus_draw - constrain controller's VBUS power usage
 * @gadget:The device whose VBUS usage is being described
 * @mA:How much current to draw, in milliAmperes.  This should be twice
 *	the value listed in the configuration descriptor bMaxPower field.
 *
 * This call is used by gadget drivers during SET_CONFIGURATION calls,
 * reporting how much power the device may consume.  For example, this
 * could affect how quickly batteries are recharged.
 *
 * Returns zero on success, else negative errno.
 */
int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_gadget_vbus_disconnect - notify controller about VBUS session end
 * @gadget:the device whose VBUS supply is being described
 * Context: can sleep
 *
 * This call is used by a driver for an external transceiver (or GPIO)
 * that detects a VBUS power session ending.  Common responses include
 * reversing everything done in usb_gadget_vbus_connect().
 *
 * Returns zero on success, else negative errno.
 */
int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

static int usb_gadget_connect_locked(struct usb_gadget *gadget)
	__must_hold(&gadget->udc->connect_lock)
{}

/**
 * usb_gadget_connect - software-controlled connect to USB host
 * @gadget:the peripheral being connected
 *
 * Enables the D+ (or potentially D-) pullup.  The host will start
 * enumerating this gadget when the pullup is active and a VBUS session
 * is active (the link is powered).
 *
 * Returns zero on success, else negative errno.
 */
int usb_gadget_connect(struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

static int usb_gadget_disconnect_locked(struct usb_gadget *gadget)
	__must_hold(&gadget->udc->connect_lock)
{}

/**
 * usb_gadget_disconnect - software-controlled disconnect from USB host
 * @gadget:the peripheral being disconnected
 *
 * Disables the D+ (or potentially D-) pullup, which the host may see
 * as a disconnect (when a VBUS session is active).  Not all systems
 * support software pullup controls.
 *
 * Following a successful disconnect, invoke the ->disconnect() callback
 * for the current gadget driver so that UDC drivers don't need to.
 *
 * Returns zero on success, else negative errno.
 */
int usb_gadget_disconnect(struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_gadget_deactivate - deactivate function which is not ready to work
 * @gadget: the peripheral being deactivated
 *
 * This routine may be used during the gadget driver bind() call to prevent
 * the peripheral from ever being visible to the USB host, unless later
 * usb_gadget_activate() is called.  For example, user mode components may
 * need to be activated before the system can talk to hosts.
 *
 * This routine may sleep; it must not be called in interrupt context
 * (such as from within a gadget driver's disconnect() callback).
 *
 * Returns zero on success, else negative errno.
 */
int usb_gadget_deactivate(struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_gadget_activate - activate function which is not ready to work
 * @gadget: the peripheral being activated
 *
 * This routine activates gadget which was previously deactivated with
 * usb_gadget_deactivate() call. It calls usb_gadget_connect() if needed.
 *
 * This routine may sleep; it must not be called in interrupt context.
 *
 * Returns zero on success, else negative errno.
 */
int usb_gadget_activate(struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

/* ------------------------------------------------------------------------- */

#ifdef	CONFIG_HAS_DMA

int usb_gadget_map_request_by_dev(struct device *dev,
		struct usb_request *req, int is_in)
{}
EXPORT_SYMBOL_GPL();

int usb_gadget_map_request(struct usb_gadget *gadget,
		struct usb_request *req, int is_in)
{}
EXPORT_SYMBOL_GPL();

void usb_gadget_unmap_request_by_dev(struct device *dev,
		struct usb_request *req, int is_in)
{}
EXPORT_SYMBOL_GPL();

void usb_gadget_unmap_request(struct usb_gadget *gadget,
		struct usb_request *req, int is_in)
{}
EXPORT_SYMBOL_GPL();

#endif	/* CONFIG_HAS_DMA */

/* ------------------------------------------------------------------------- */

/**
 * usb_gadget_giveback_request - give the request back to the gadget layer
 * @ep: the endpoint to be used with with the request
 * @req: the request being given back
 *
 * This is called by device controller drivers in order to return the
 * completed request back to the gadget layer.
 */
void usb_gadget_giveback_request(struct usb_ep *ep,
		struct usb_request *req)
{}
EXPORT_SYMBOL_GPL();

/* ------------------------------------------------------------------------- */

/**
 * gadget_find_ep_by_name - returns ep whose name is the same as sting passed
 *	in second parameter or NULL if searched endpoint not found
 * @g: controller to check for quirk
 * @name: name of searched endpoint
 */
struct usb_ep *gadget_find_ep_by_name(struct usb_gadget *g, const char *name)
{}
EXPORT_SYMBOL_GPL();

/* ------------------------------------------------------------------------- */

int usb_gadget_ep_match_desc(struct usb_gadget *gadget,
		struct usb_ep *ep, struct usb_endpoint_descriptor *desc,
		struct usb_ss_ep_comp_descriptor *ep_comp)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_gadget_check_config - checks if the UDC can support the binded
 *	configuration
 * @gadget: controller to check the USB configuration
 *
 * Ensure that a UDC is able to support the requested resources by a
 * configuration, and that there are no resource limitations, such as
 * internal memory allocated to all requested endpoints.
 *
 * Returns zero on success, else a negative errno.
 */
int usb_gadget_check_config(struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

/* ------------------------------------------------------------------------- */

static void usb_gadget_state_work(struct work_struct *work)
{}

void usb_gadget_set_state(struct usb_gadget *gadget,
		enum usb_device_state state)
{}
EXPORT_SYMBOL_GPL();

/* ------------------------------------------------------------------------- */

/* Acquire connect_lock before calling this function. */
static int usb_udc_connect_control_locked(struct usb_udc *udc) __must_hold(&udc->connect_lock)
{}

static void vbus_event_work(struct work_struct *work)
{}

/**
 * usb_udc_vbus_handler - updates the udc core vbus status, and try to
 * connect or disconnect gadget
 * @gadget: The gadget which vbus change occurs
 * @status: The vbus status
 *
 * The udc driver calls it when it wants to connect or disconnect gadget
 * according to vbus status.
 *
 * This function can be invoked from interrupt context by irq handlers of
 * the gadget drivers, however, usb_udc_connect_control() has to run in
 * non-atomic context due to the following:
 * a. Some of the gadget driver implementations expect the ->pullup
 * callback to be invoked in non-atomic context.
 * b. usb_gadget_disconnect() acquires udc_lock which is a mutex.
 * Hence offload invocation of usb_udc_connect_control() to workqueue.
 */
void usb_udc_vbus_handler(struct usb_gadget *gadget, bool status)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_gadget_udc_reset - notifies the udc core that bus reset occurs
 * @gadget: The gadget which bus reset occurs
 * @driver: The gadget driver we want to notify
 *
 * If the udc driver has bus reset handler, it needs to call this when the bus
 * reset occurs, it notifies the gadget driver that the bus reset occurs as
 * well as updates gadget state.
 */
void usb_gadget_udc_reset(struct usb_gadget *gadget,
		struct usb_gadget_driver *driver)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_gadget_udc_start_locked - tells usb device controller to start up
 * @udc: The UDC to be started
 *
 * This call is issued by the UDC Class driver when it's about
 * to register a gadget driver to the device controller, before
 * calling gadget driver's bind() method.
 *
 * It allows the controller to be powered off until strictly
 * necessary to have it powered on.
 *
 * Returns zero on success, else negative errno.
 *
 * Caller should acquire connect_lock before invoking this function.
 */
static inline int usb_gadget_udc_start_locked(struct usb_udc *udc)
	__must_hold(&udc->connect_lock)
{}

/**
 * usb_gadget_udc_stop_locked - tells usb device controller we don't need it anymore
 * @udc: The UDC to be stopped
 *
 * This call is issued by the UDC Class driver after calling
 * gadget driver's unbind() method.
 *
 * The details are implementation specific, but it can go as
 * far as powering off UDC completely and disable its data
 * line pullups.
 *
 * Caller should acquire connect lock before invoking this function.
 */
static inline void usb_gadget_udc_stop_locked(struct usb_udc *udc)
	__must_hold(&udc->connect_lock)
{}

/**
 * usb_gadget_udc_set_speed - tells usb device controller speed supported by
 *    current driver
 * @udc: The device we want to set maximum speed
 * @speed: The maximum speed to allowed to run
 *
 * This call is issued by the UDC Class driver before calling
 * usb_gadget_udc_start() in order to make sure that we don't try to
 * connect on speeds the gadget driver doesn't support.
 */
static inline void usb_gadget_udc_set_speed(struct usb_udc *udc,
					    enum usb_device_speed speed)
{}

/**
 * usb_gadget_enable_async_callbacks - tell usb device controller to enable asynchronous callbacks
 * @udc: The UDC which should enable async callbacks
 *
 * This routine is used when binding gadget drivers.  It undoes the effect
 * of usb_gadget_disable_async_callbacks(); the UDC driver should enable IRQs
 * (if necessary) and resume issuing callbacks.
 *
 * This routine will always be called in process context.
 */
static inline void usb_gadget_enable_async_callbacks(struct usb_udc *udc)
{}

/**
 * usb_gadget_disable_async_callbacks - tell usb device controller to disable asynchronous callbacks
 * @udc: The UDC which should disable async callbacks
 *
 * This routine is used when unbinding gadget drivers.  It prevents a race:
 * The UDC driver doesn't know when the gadget driver's ->unbind callback
 * runs, so unless it is told to disable asynchronous callbacks, it might
 * issue a callback (such as ->disconnect) after the unbind has completed.
 *
 * After this function runs, the UDC driver must suppress all ->suspend,
 * ->resume, ->disconnect, ->reset, and ->setup callbacks to the gadget driver
 * until async callbacks are again enabled.  A simple-minded but effective
 * way to accomplish this is to tell the UDC hardware not to generate any
 * more IRQs.
 *
 * Request completion callbacks must still be issued.  However, it's okay
 * to defer them until the request is cancelled, since the pull-up will be
 * turned off during the time period when async callbacks are disabled.
 *
 * This routine will always be called in process context.
 */
static inline void usb_gadget_disable_async_callbacks(struct usb_udc *udc)
{}

/**
 * usb_udc_release - release the usb_udc struct
 * @dev: the dev member within usb_udc
 *
 * This is called by driver's core in order to free memory once the last
 * reference is released.
 */
static void usb_udc_release(struct device *dev)
{}

static const struct attribute_group *usb_udc_attr_groups[];

static void usb_udc_nop_release(struct device *dev)
{}

/**
 * usb_initialize_gadget - initialize a gadget and its embedded struct device
 * @parent: the parent device to this udc. Usually the controller driver's
 * device.
 * @gadget: the gadget to be initialized.
 * @release: a gadget release function.
 */
void usb_initialize_gadget(struct device *parent, struct usb_gadget *gadget,
		void (*release)(struct device *dev))
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_add_gadget - adds a new gadget to the udc class driver list
 * @gadget: the gadget to be added to the list.
 *
 * Returns zero on success, negative errno otherwise.
 * Does not do a final usb_put_gadget() if an error occurs.
 */
int usb_add_gadget(struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_add_gadget_udc_release - adds a new gadget to the udc class driver list
 * @parent: the parent device to this udc. Usually the controller driver's
 * device.
 * @gadget: the gadget to be added to the list.
 * @release: a gadget release function.
 *
 * Returns zero on success, negative errno otherwise.
 * Calls the gadget release function in the latter case.
 */
int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
		void (*release)(struct device *dev))
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_get_gadget_udc_name - get the name of the first UDC controller
 * This functions returns the name of the first UDC controller in the system.
 * Please note that this interface is usefull only for legacy drivers which
 * assume that there is only one UDC controller in the system and they need to
 * get its name before initialization. There is no guarantee that the UDC
 * of the returned name will be still available, when gadget driver registers
 * itself.
 *
 * Returns pointer to string with UDC controller name on success, NULL
 * otherwise. Caller should kfree() returned string.
 */
char *usb_get_gadget_udc_name(void)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_add_gadget_udc - adds a new gadget to the udc class driver list
 * @parent: the parent device to this udc. Usually the controller
 * driver's device.
 * @gadget: the gadget to be added to the list
 *
 * Returns zero on success, negative errno otherwise.
 */
int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_del_gadget - deletes a gadget and unregisters its udc
 * @gadget: the gadget to be deleted.
 *
 * This will unbind @gadget, if it is bound.
 * It will not do a final usb_put_gadget().
 */
void usb_del_gadget(struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

/**
 * usb_del_gadget_udc - unregisters a gadget
 * @gadget: the gadget to be unregistered.
 *
 * Calls usb_del_gadget() and does a final usb_put_gadget().
 */
void usb_del_gadget_udc(struct usb_gadget *gadget)
{}
EXPORT_SYMBOL_GPL();

/* ------------------------------------------------------------------------- */

static int gadget_match_driver(struct device *dev, const struct device_driver *drv)
{}

static int gadget_bind_driver(struct device *dev)
{}

static void gadget_unbind_driver(struct device *dev)
{}

/* ------------------------------------------------------------------------- */

int usb_gadget_register_driver_owner(struct usb_gadget_driver *driver,
		struct module *owner, const char *mod_name)
{}
EXPORT_SYMBOL_GPL();

int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
{}
EXPORT_SYMBOL_GPL();

/* ------------------------------------------------------------------------- */

static ssize_t srp_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t n)
{}
static DEVICE_ATTR_WO(srp);

static ssize_t soft_connect_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t n)
{}
static DEVICE_ATTR_WO(soft_connect);

static ssize_t state_show(struct device *dev, struct device_attribute *attr,
			  char *buf)
{}
static DEVICE_ATTR_RO(state);

static ssize_t function_show(struct device *dev, struct device_attribute *attr,
			     char *buf)
{}
static DEVICE_ATTR_RO(function);

#define USB_UDC_SPEED_ATTR(name, param)

static USB_UDC_SPEED_ATTR(current_speed, speed);
static USB_UDC_SPEED_ATTR(maximum_speed, max_speed);

#define USB_UDC_ATTR(name)

static USB_UDC_ATTR(is_otg);
static USB_UDC_ATTR(is_a_peripheral);
static USB_UDC_ATTR(b_hnp_enable);
static USB_UDC_ATTR(a_hnp_support);
static USB_UDC_ATTR(a_alt_hnp_support);
static USB_UDC_ATTR(is_selfpowered);

static struct attribute *usb_udc_attrs[] =;

static const struct attribute_group usb_udc_attr_group =;

static const struct attribute_group *usb_udc_attr_groups[] =;

static int usb_udc_uevent(const struct device *dev, struct kobj_uevent_env *env)
{}

static const struct class udc_class =;

static const struct bus_type gadget_bus_type =;

static int __init usb_udc_init(void)
{}
subsys_initcall(usb_udc_init);

static void __exit usb_udc_exit(void)
{}
module_exit(usb_udc_exit);

MODULE_DESCRIPTION();
MODULE_AUTHOR();
MODULE_LICENSE();