/*
   * <linux/usb/gadget.h>
   *
   * We call the USB code inside a Linux-based peripheral device a "gadget"
   * driver, except for the hardware-specific bus glue.  One USB host can
   * master many USB gadgets, but the gadgets are only slaved to one host.
   *
   *
   * (C) Copyright 2002-2004 by David Brownell
   * All Rights Reserved.
   *
   * This software is licensed under the GNU GPL version 2.
   */
  
  #ifndef __LINUX_USB_GADGET_H
  #define __LINUX_USB_GADGET_H
  
  #include <linux/device.h>
  #include <linux/errno.h>
  #include <linux/init.h>
  #include <linux/list.h>
  #include <linux/slab.h>
  #include <linux/scatterlist.h>
  #include <linux/types.h>
  #include <linux/workqueue.h>
  #include <linux/usb/ch9.h>
  
  struct usb_ep;
  
  /**
   * struct usb_request - describes one i/o request
   * @buf: Buffer used for data.  Always provide this; some controllers
   *	only use PIO, or don't use DMA for some endpoints.
   * @dma: DMA address corresponding to 'buf'.  If you don't set this
   *	field, and the usb controller needs one, it is responsible
   *	for mapping and unmapping the buffer.
   * @sg: a scatterlist for SG-capable controllers.
   * @num_sgs: number of SG entries
   * @num_mapped_sgs: number of SG entries mapped to DMA (internal)
   * @length: Length of that data
   * @stream_id: The stream id, when USB3.0 bulk streams are being used
   * @no_interrupt: If true, hints that no completion irq is needed.
   *	Helpful sometimes with deep request queues that are handled
   *	directly by DMA controllers.
   * @zero: If true, when writing data, makes the last packet be "short"
   *     by adding a zero length packet as needed;
   * @short_not_ok: When reading data, makes short packets be
   *     treated as errors (queue stops advancing till cleanup).
   * @complete: Function called when request completes, so this request and
   *	its buffer may be re-used.  The function will always be called with
   *	interrupts disabled, and it must not sleep.
   *	Reads terminate with a short packet, or when the buffer fills,
   *	whichever comes first.  When writes terminate, some data bytes
   *	will usually still be in flight (often in a hardware fifo).
   *	Errors (for reads or writes) stop the queue from advancing
   *	until the completion function returns, so that any transfers
   *	invalidated by the error may first be dequeued.
   * @context: For use by the completion callback
   * @list: For use by the gadget driver.
   * @status: Reports completion code, zero or a negative errno.
   *	Normally, faults block the transfer queue from advancing until
   *	the completion callback returns.
   *	Code "-ESHUTDOWN" indicates completion caused by device disconnect,
   *	or when the driver disabled the endpoint.
   * @actual: Reports bytes transferred to/from the buffer.  For reads (OUT
   *	transfers) this may be less than the requested length.  If the
   *	short_not_ok flag is set, short reads are treated as errors
   *	even when status otherwise indicates successful completion.
   *	Note that for writes (IN transfers) some data bytes may still
   *	reside in a device-side FIFO when the request is reported as
   *	complete.
   *
   * These are allocated/freed through the endpoint they're used with.  The
   * hardware's driver can add extra per-request data to the memory it returns,
   * which often avoids separate memory allocations (potential failures),
   * later when the request is queued.
   *
   * Request flags affect request handling, such as whether a zero length
   * packet is written (the "zero" flag), whether a short read should be
   * treated as an error (blocking request queue advance, the "short_not_ok"
   * flag), or hinting that an interrupt is not required (the "no_interrupt"
   * flag, for use with deep request queues).
   *
   * Bulk endpoints can use any size buffers, and can also be used for interrupt
   * transfers. interrupt-only endpoints can be much less functional.
   *
   * NOTE:  this is analogous to 'struct urb' on the host side, except that
   * it's thinner and promotes more pre-allocation.
   */
  
  struct usb_request {
  	void			*buf;
  	unsigned		length;
  	dma_addr_t		dma;
  
  	struct scatterlist	*sg;
  	unsigned		num_sgs;
  	unsigned		num_mapped_sgs;
  
  	unsigned		stream_id:16;
  	unsigned		no_interrupt:1;
  	unsigned		zero:1;
  	unsigned		short_not_ok:1;
  
  	void			(*complete)(struct usb_ep *ep,
  					struct usb_request *req);
  	void			*context;
  	struct list_head	list;
  
  	int			status;
  	unsigned		actual;
  };
  
  /*-------------------------------------------------------------------------*/
  
  /* endpoint-specific parts of the api to the usb controller hardware.
   * unlike the urb model, (de)multiplexing layers are not required.
   * (so this api could slash overhead if used on the host side...)
   *
   * note that device side usb controllers commonly differ in how many
   * endpoints they support, as well as their capabilities.
   */
  struct usb_ep_ops {
  	int (*enable) (struct usb_ep *ep,
  		const struct usb_endpoint_descriptor *desc);
  	int (*disable) (struct usb_ep *ep);
  
  	struct usb_request *(*alloc_request) (struct usb_ep *ep,
  		gfp_t gfp_flags);
  	void (*free_request) (struct usb_ep *ep, struct usb_request *req);
  
  	int (*queue) (struct usb_ep *ep, struct usb_request *req,
  		gfp_t gfp_flags);
  	int (*dequeue) (struct usb_ep *ep, struct usb_request *req);
  
  	int (*set_halt) (struct usb_ep *ep, int value);
  	int (*set_wedge) (struct usb_ep *ep);
  
  	int (*fifo_status) (struct usb_ep *ep);
  	void (*fifo_flush) (struct usb_ep *ep);
  };
  
  /**
   * struct usb_ep - device side representation of USB endpoint
   * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"
   * @ops: Function pointers used to access hardware-specific operations.
   * @ep_list:the gadget's ep_list holds all of its endpoints
   * @maxpacket:The maximum packet size used on this endpoint.  The initial
   *	value can sometimes be reduced (hardware allowing), according to
   *      the endpoint descriptor used to configure the endpoint.
   * @maxpacket_limit:The maximum packet size value which can be handled by this
   *	endpoint. It's set once by UDC driver when endpoint is initialized, and
   *	should not be changed. Should not be confused with maxpacket.
   * @max_streams: The maximum number of streams supported
   *	by this EP (0 - 16, actual number is 2^n)
   * @mult: multiplier, 'mult' value for SS Isoc EPs
   * @maxburst: the maximum number of bursts supported by this EP (for usb3)
   * @driver_data:for use by the gadget driver.
   * @address: used to identify the endpoint when finding descriptor that
   *	matches connection speed
   * @desc: endpoint descriptor.  This pointer is set before the endpoint is
   *	enabled and remains valid until the endpoint is disabled.
   * @comp_desc: In case of SuperSpeed support, this is the endpoint companion
   *	descriptor that is used to configure the endpoint
   *
   * the bus controller driver lists all the general purpose endpoints in
   * gadget->ep_list.  the control endpoint (gadget->ep0) is not in that list,
   * and is accessed only in response to a driver setup() callback.
   */
  struct usb_ep {
  	void			*driver_data;
  
  	const char		*name;
  	const struct usb_ep_ops	*ops;
  	struct list_head	ep_list;
  	unsigned		maxpacket:16;
  	unsigned		maxpacket_limit:16;
  	unsigned		max_streams:16;
  	unsigned		mult:2;
  	unsigned		maxburst:5;
  	u8			address;
  	const struct usb_endpoint_descriptor	*desc;
  	const struct usb_ss_ep_comp_descriptor	*comp_desc;
  };
  
  /*-------------------------------------------------------------------------*/
  
  /**
   * 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 shoud be used only in UDC drivers to initialize endpoint
   * (usually in probe function).
   */
  static inline void usb_ep_set_maxpacket_limit(struct usb_ep *ep,
  					      unsigned maxpacket_limit)
  {
  	ep->maxpacket_limit = maxpacket_limit;
  	ep->maxpacket = maxpacket_limit;
  }
  
  /**
   * 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 master".)
   *
   * returns zero, or a negative error code.
   */
  static inline int usb_ep_enable(struct usb_ep *ep)
  {
  	return ep->ops->enable(ep, ep->desc);
  }
  
  /**
   * 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.
   *
   * returns zero, or a negative error code.
   */
  static inline int usb_ep_disable(struct usb_ep *ep)
  {
  	return ep->ops->disable(ep);
  }
  
  /**
   * 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.
   */
  static inline struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,
  						       gfp_t gfp_flags)
  {
  	return ep->ops->alloc_request(ep, gfp_flags);
  }
  
  /**
   * 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).
   */
  static inline void usb_ep_free_request(struct usb_ep *ep,
  				       struct usb_request *req)
  {
  	ep->ops->free_request(ep, req);
  }
  
  /**
   * 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.
   *
   * 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.
   */
  static inline int usb_ep_queue(struct usb_ep *ep,
  			       struct usb_request *req, gfp_t gfp_flags)
  {
  	return ep->ops->queue(ep, req, gfp_flags);
  }
  
  /**
   * 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 its
   * completion routine is called (with status -ECONNRESET); else a negative
   * error code is returned.
   *
   * 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).
   */
  static inline int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
  {
  	return ep->ops->dequeue(ep, req);
  }
  
  /**
   * 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.
   *
   * 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.
   */
  static inline int usb_ep_set_halt(struct usb_ep *ep)
  {
  	return ep->ops->set_halt(ep, 1);
  }
  
  /**
   * 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.
   *
   * 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.
   */
  static inline int usb_ep_clear_halt(struct usb_ep *ep)
  {
  	return ep->ops->set_halt(ep, 0);
  }
  
  /**
   * 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.
   *
   * Returns zero on success, else negative errno.
   */
  static inline int
  usb_ep_set_wedge(struct usb_ep *ep)
  {
  	if (ep->ops->set_wedge)
  		return ep->ops->set_wedge(ep);
  	else
  		return ep->ops->set_halt(ep, 1);
  }
  
  /**
   * 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 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.
   */
  static inline int usb_ep_fifo_status(struct usb_ep *ep)
  {
  	if (ep->ops->fifo_status)
  		return ep->ops->fifo_status(ep);
  	else
  		return -EOPNOTSUPP;
  }
  
  /**
   * 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.
   */
  static inline void usb_ep_fifo_flush(struct usb_ep *ep)
  {
  	if (ep->ops->fifo_flush)
  		ep->ops->fifo_flush(ep);
  }
  
  
  /*-------------------------------------------------------------------------*/
  
  struct usb_dcd_config_params {
  	__u8  bU1devExitLat;	/* U1 Device exit Latency */
  #define USB_DEFAULT_U1_DEV_EXIT_LAT	0x01	/* Less then 1 microsec */
  	__le16 bU2DevExitLat;	/* U2 Device exit Latency */
  #define USB_DEFAULT_U2_DEV_EXIT_LAT	0x1F4	/* Less then 500 microsec */
  };
  
  
  struct usb_gadget;
  struct usb_gadget_driver;
  
  /* the rest of the api to the controller hardware: device operations,
   * which don't involve endpoints (or i/o).
   */
  struct usb_gadget_ops {
  	int	(*get_frame)(struct usb_gadget *);
  	int	(*wakeup)(struct usb_gadget *);
  	int	(*set_selfpowered) (struct usb_gadget *, int is_selfpowered);
  	int	(*vbus_session) (struct usb_gadget *, int is_active);
  	int	(*vbus_draw) (struct usb_gadget *, unsigned mA);
  	int	(*pullup) (struct usb_gadget *, int is_on);
  	int	(*ioctl)(struct usb_gadget *,
  				unsigned code, unsigned long param);
  	void	(*get_config_params)(struct usb_dcd_config_params *);
  	int	(*udc_start)(struct usb_gadget *,
  			struct usb_gadget_driver *);
  	int	(*udc_stop)(struct usb_gadget *,
  			struct usb_gadget_driver *);
  };
  
  /**
   * struct usb_gadget - represents a usb slave device
   * @work: (internal use) Workqueue to be used for sysfs_notify()
   * @ops: Function pointers used to access hardware-specific operations.
   * @ep0: Endpoint zero, used when reading or writing responses to
   *	driver setup() requests
   * @ep_list: List of other endpoints supported by the device.
   * @speed: Speed of current connection to USB host.
   * @max_speed: Maximal speed the UDC can handle.  UDC must support this
   *      and all slower speeds.
   * @state: the state we are now (attached, suspended, configured, etc)
   * @name: Identifies the controller hardware type.  Used in diagnostics
   *	and sometimes configuration.
   * @dev: Driver model state for this abstract device.
   * @out_epnum: last used out ep number
   * @in_epnum: last used in ep number
   * @sg_supported: true if we can handle scatter-gather
   * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
   *	gadget driver must provide a USB OTG descriptor.
   * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable
   *	is in the Mini-AB jack, and HNP has been used to switch roles
   *	so that the "A" device currently acts as A-Peripheral, not A-Host.
   * @a_hnp_support: OTG device feature flag, indicating that the A-Host
   *	supports HNP at this port.
   * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host
   *	only supports HNP on a different root port.
   * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
   *	enabled HNP support.
   * @quirk_ep_out_aligned_size: epout requires buffer size to be aligned to
   *	MaxPacketSize.
   *
   * Gadgets have a mostly-portable "gadget driver" implementing device
   * functions, handling all usb configurations and interfaces.  Gadget
   * drivers talk to hardware-specific code indirectly, through ops vectors.
   * That insulates the gadget driver from hardware details, and packages
   * the hardware endpoints through generic i/o queues.  The "usb_gadget"
   * and "usb_ep" interfaces provide that insulation from the hardware.
   *
   * Except for the driver data, all fields in this structure are
   * read-only to the gadget driver.  That driver data is part of the
   * "driver model" infrastructure in 2.6 (and later) kernels, and for
   * earlier systems is grouped in a similar structure that's not known
   * to the rest of the kernel.
   *
   * Values of the three OTG device feature flags are updated before the
   * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before
   * driver suspend() calls.  They are valid only when is_otg, and when the
   * device is acting as a B-Peripheral (so is_a_peripheral is false).
   */
  struct usb_gadget {
  	struct work_struct		work;
  	/* readonly to gadget driver */
  	const struct usb_gadget_ops	*ops;
  	struct usb_ep			*ep0;
  	struct list_head		ep_list;	/* of usb_ep */
  	enum usb_device_speed		speed;
  	enum usb_device_speed		max_speed;
  	enum usb_device_state		state;
  	const char			*name;
  	struct device			dev;
  	unsigned			out_epnum;
  	unsigned			in_epnum;
  
  	unsigned			sg_supported:1;
  	unsigned			is_otg:1;
  	unsigned			is_a_peripheral:1;
  	unsigned			b_hnp_enable:1;
  	unsigned			a_hnp_support:1;
  	unsigned			a_alt_hnp_support:1;
  	unsigned			host_request_flag:1;
  	unsigned			quirk_ep_out_aligned_size:1;
  };
  #define work_to_gadget(w)	(container_of((w), struct usb_gadget, work))
  
  static inline void set_gadget_data(struct usb_gadget *gadget, void *data)
  	{ dev_set_drvdata(&gadget->dev, data); }
  static inline void *get_gadget_data(struct usb_gadget *gadget)
  	{ return dev_get_drvdata(&gadget->dev); }
  static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
  {
  	return container_of(dev, struct usb_gadget, dev);
  }
  
  /* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */
  #define gadget_for_each_ep(tmp, gadget) \
  	list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
  
  
  /**
   * usb_ep_align_maybe - returns @len aligned to ep's maxpacketsize if gadget
   *	requires quirk_ep_out_aligned_size, otherwise reguens len.
   * @g: controller to check for quirk
   * @ep: the endpoint whose maxpacketsize is used to align @len
   * @len: buffer size's length to align to @ep's maxpacketsize
   *
   * This helper is used in case it's required for any reason to check and maybe
   * align buffer's size to an ep's maxpacketsize.
   */
  static inline size_t
  usb_ep_align_maybe(struct usb_gadget *g, struct usb_ep *ep, size_t len)
  {
  	return !g->quirk_ep_out_aligned_size ? len :
  			round_up(len, (size_t)ep->desc->wMaxPacketSize);
  }
  
  /**
   * gadget_is_dualspeed - return true iff the hardware handles high speed
   * @g: controller that might support both high and full speeds
   */
  static inline int gadget_is_dualspeed(struct usb_gadget *g)
  {
  	return g->max_speed >= USB_SPEED_HIGH;
  }
  
  /**
   * gadget_is_superspeed() - return true if the hardware handles superspeed
   * @g: controller that might support superspeed
   */
  static inline int gadget_is_superspeed(struct usb_gadget *g)
  {
  	return g->max_speed >= USB_SPEED_SUPER;
  }
  
  /**
   * gadget_is_otg - return true iff the hardware is OTG-ready
   * @g: controller that might have a Mini-AB connector
   *
   * This is a runtime test, since kernels with a USB-OTG stack sometimes
   * run on boards which only have a Mini-B (or Mini-A) connector.
   */
  static inline int gadget_is_otg(struct usb_gadget *g)
  {
  #ifdef CONFIG_USB_OTG
  	return g->is_otg;
  #else
  	return 0;
  #endif
  }
  
  /**
   * 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.
   */
  static inline int usb_gadget_frame_number(struct usb_gadget *gadget)
  {
  	return gadget->ops->get_frame(gadget);
  }
  
  /**
   * 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.
   */
  static inline int usb_gadget_wakeup(struct usb_gadget *gadget)
  {
  	if (!gadget->ops->wakeup)
  		return -EOPNOTSUPP;
  	return gadget->ops->wakeup(gadget);
  }
  
  /**
   * 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.
   */
  static inline int usb_gadget_set_selfpowered(struct usb_gadget *gadget)
  {
  	if (!gadget->ops->set_selfpowered)
  		return -EOPNOTSUPP;
  	return gadget->ops->set_selfpowered(gadget, 1);
  }
  
  /**
   * 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.
   */
  static inline int usb_gadget_clear_selfpowered(struct usb_gadget *gadget)
  {
  	if (!gadget->ops->set_selfpowered)
  		return -EOPNOTSUPP;
  	return gadget->ops->set_selfpowered(gadget, 0);
  }
  
  /**
   * 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.
   */
  static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget)
  {
  	if (!gadget->ops->vbus_session)
  		return -EOPNOTSUPP;
  	return gadget->ops->vbus_session(gadget, 1);
  }
  
  /**
   * 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.
   */
  static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
  {
  	if (!gadget->ops->vbus_draw)
  		return -EOPNOTSUPP;
  	return gadget->ops->vbus_draw(gadget, mA);
  }
  
  /**
   * 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.
   */
  static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
  {
  	if (!gadget->ops->vbus_session)
  		return -EOPNOTSUPP;
  	return gadget->ops->vbus_session(gadget, 0);
  }
  
  /**
   * 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).  This pullup is always enabled unless
   * usb_gadget_disconnect() has been used to disable it.
   *
   * Returns zero on success, else negative errno.
   */
  static inline int usb_gadget_connect(struct usb_gadget *gadget)
  {
  	if (!gadget->ops->pullup)
  		return -EOPNOTSUPP;
  	return gadget->ops->pullup(gadget, 1);
  }
  
  /**
   * 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.
   *
   * 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_connect() is called.  For example, user mode components may
   * need to be activated before the system can talk to hosts.
   *
   * Returns zero on success, else negative errno.
   */
  static inline int usb_gadget_disconnect(struct usb_gadget *gadget)
  {
  	if (!gadget->ops->pullup)
  		return -EOPNOTSUPP;
  	return gadget->ops->pullup(gadget, 0);
  }
  
  
  /*-------------------------------------------------------------------------*/
  
  /**
   * struct usb_gadget_driver - driver for usb 'slave' devices
   * @function: String describing the gadget's function
   * @max_speed: Highest speed the driver handles.
   * @setup: Invoked for ep0 control requests that aren't handled by
   *	the hardware level driver. Most calls must be handled by
   *	the gadget driver, including descriptor and configuration
   *	management.  The 16 bit members of the setup data are in
   *	USB byte order. Called in_interrupt; this may not sleep.  Driver
   *	queues a response to ep0, or returns negative to stall.
   * @disconnect: Invoked after all transfers have been stopped,
   *	when the host is disconnected.  May be called in_interrupt; this
   *	may not sleep.  Some devices can't detect disconnect, so this might
   *	not be called except as part of controller shutdown.
   * @bind: the driver's bind callback
   * @unbind: Invoked when the driver is unbound from a gadget,
   *	usually from rmmod (after a disconnect is reported).
   *	Called in a context that permits sleeping.
   * @suspend: Invoked on USB suspend.  May be called in_interrupt.
   * @resume: Invoked on USB resume.  May be called in_interrupt.
   * @driver: Driver model state for this driver.
   *
   * Devices are disabled till a gadget driver successfully bind()s, which
   * means the driver will handle setup() requests needed to enumerate (and
   * meet "chapter 9" requirements) then do some useful work.
   *
   * If gadget->is_otg is true, the gadget driver must provide an OTG
   * descriptor during enumeration, or else fail the bind() call.  In such
   * cases, no USB traffic may flow until both bind() returns without
   * having called usb_gadget_disconnect(), and the USB host stack has
   * initialized.
   *
   * Drivers use hardware-specific knowledge to configure the usb hardware.
   * endpoint addressing is only one of several hardware characteristics that
   * are in descriptors the ep0 implementation returns from setup() calls.
   *
   * Except for ep0 implementation, most driver code shouldn't need change to
   * run on top of different usb controllers.  It'll use endpoints set up by
   * that ep0 implementation.
   *
   * The usb controller driver handles a few standard usb requests.  Those
   * include set_address, and feature flags for devices, interfaces, and
   * endpoints (the get_status, set_feature, and clear_feature requests).
   *
   * Accordingly, the driver's setup() callback must always implement all
   * get_descriptor requests, returning at least a device descriptor and
   * a configuration descriptor.  Drivers must make sure the endpoint
   * descriptors match any hardware constraints. Some hardware also constrains
   * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
   *
   * The driver's setup() callback must also implement set_configuration,
   * and should also implement set_interface, get_configuration, and
   * get_interface.  Setting a configuration (or interface) is where
   * endpoints should be activated or (config 0) shut down.
   *
   * (Note that only the default control endpoint is supported.  Neither
   * hosts nor devices generally support control traffic except to ep0.)
   *
   * Most devices will ignore USB suspend/resume operations, and so will
   * not provide those callbacks.  However, some may need to change modes
   * when the host is not longer directing those activities.  For example,
   * local controls (buttons, dials, etc) may need to be re-enabled since
   * the (remote) host can't do that any longer; or an error state might
   * be cleared, to make the device behave identically whether or not
   * power is maintained.
   */
  struct usb_gadget_driver {
  	char			*function;
  	enum usb_device_speed	max_speed;
  	int			(*bind)(struct usb_gadget *gadget,
  					struct usb_gadget_driver *driver);
  	void			(*unbind)(struct usb_gadget *);
  	int			(*setup)(struct usb_gadget *,
  					const struct usb_ctrlrequest *);
  	void			(*disconnect)(struct usb_gadget *);
  	void			(*suspend)(struct usb_gadget *);
  	void			(*resume)(struct usb_gadget *);
  
  	/* FIXME support safe rmmod */
  	struct device_driver	driver;
  };
  
  
  
  /*-------------------------------------------------------------------------*/
  
  /* driver modules register and unregister, as usual.
   * these calls must be made in a context that can sleep.
   *
   * these will usually be implemented directly by the hardware-dependent
   * usb bus interface driver, which will only support a single driver.
   */
  
  /**
   * usb_gadget_probe_driver - probe a gadget driver
   * @driver: the driver being registered
   * Context: can sleep
   *
   * Call this in your gadget driver's module initialization function,
   * to tell the underlying usb controller driver about your driver.
   * The @bind() function will be called to bind it to a gadget before this
   * registration call returns.  It's expected that the @bind() function will
   * be in init sections.
   */
  int usb_gadget_probe_driver(struct usb_gadget_driver *driver);
  
  /**
   * usb_gadget_unregister_driver - unregister a gadget driver
   * @driver:the driver being unregistered
   * Context: can sleep
   *
   * Call this in your gadget driver's module cleanup function,
   * to tell the underlying usb controller that your driver is
   * going away.  If the controller is connected to a USB host,
   * it will first disconnect().  The driver is also requested
   * to unbind() and clean up any device state, before this procedure
   * finally returns.  It's expected that the unbind() functions
   * will in in exit sections, so may not be linked in some kernels.
   */
  int usb_gadget_unregister_driver(struct usb_gadget_driver *driver);
  
  extern int usb_add_gadget_udc_release(struct device *parent,
  		struct usb_gadget *gadget, void (*release)(struct device *dev));
  extern int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget);
  extern void usb_del_gadget_udc(struct usb_gadget *gadget);
  extern int udc_attach_driver(const char *name,
  		struct usb_gadget_driver *driver);
  
  /*-------------------------------------------------------------------------*/
  
  /* utility to simplify dealing with string descriptors */
  
  /**
   * struct usb_string - wraps a C string and its USB id
   * @id:the (nonzero) ID for this string
   * @s:the string, in UTF-8 encoding
   *
   * If you're using usb_gadget_get_string(), use this to wrap a string
   * together with its ID.
   */
  struct usb_string {
  	u8			id;
  	const char		*s;
  };
  
  /**
   * struct usb_gadget_strings - a set of USB strings in a given language
   * @language:identifies the strings' language (0x0409 for en-us)
   * @strings:array of strings with their ids
   *
   * If you're using usb_gadget_get_string(), use this to wrap all the
   * strings for a given language.
   */
  struct usb_gadget_strings {
  	u16			language;	/* 0x0409 for en-us */
  	struct usb_string	*strings;
  };
  
  struct usb_gadget_string_container {
  	struct list_head        list;
  	u8                      *stash[0];
  };
  
  /* put descriptor for string with that id into buf (buflen >= 256) */
  int usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf);
  
  /*-------------------------------------------------------------------------*/
  
  /* utility to simplify managing config descriptors */
  
  /* write vector of descriptors into buffer */
  int usb_descriptor_fillbuf(void *, unsigned,
  		const struct usb_descriptor_header **);
  
  /* build config descriptor from single descriptor vector */
  int usb_gadget_config_buf(const struct usb_config_descriptor *config,
  	void *buf, unsigned buflen, const struct usb_descriptor_header **desc);
  
  /* copy a NULL-terminated vector of descriptors */
  struct usb_descriptor_header **usb_copy_descriptors(
  		struct usb_descriptor_header **);
  
  /**
   * usb_free_descriptors - free descriptors returned by usb_copy_descriptors()
   * @v: vector of descriptors
   */
  static inline void usb_free_descriptors(struct usb_descriptor_header **v)
  {
  	kfree(v);
  }
  
  struct usb_function;
  int usb_assign_descriptors(struct usb_function *f,
  		struct usb_descriptor_header **fs,
  		struct usb_descriptor_header **hs,
  		struct usb_descriptor_header **ss);
  void usb_free_all_descriptors(struct usb_function *f);
  
  /*-------------------------------------------------------------------------*/
  
  /* utility to simplify map/unmap of usb_requests to/from DMA */
  
  extern int usb_gadget_map_request(struct usb_gadget *gadget,
  		struct usb_request *req, int is_in);
  
  extern void usb_gadget_unmap_request(struct usb_gadget *gadget,
  		struct usb_request *req, int is_in);
  
  /*-------------------------------------------------------------------------*/
  
  /* utility to set gadget state properly */
  
  extern void usb_gadget_set_state(struct usb_gadget *gadget,
  		enum usb_device_state state);
  
  /*-------------------------------------------------------------------------*/
  
  /* utility wrapping a simple endpoint selection policy */
  
  extern struct usb_ep *usb_ep_autoconfig(struct usb_gadget *,
  			struct usb_endpoint_descriptor *);
  
  
  extern struct usb_ep *usb_ep_autoconfig_ss(struct usb_gadget *,
  			struct usb_endpoint_descriptor *,
  			struct usb_ss_ep_comp_descriptor *);
  
  extern void usb_ep_autoconfig_reset(struct usb_gadget *);
  
  #endif /* __LINUX_USB_GADGET_H */