text: /*
   * composite.h -- framework for usb gadgets which are composite devices
   *
   * Copyright (C) 2006-2008 David Brownell
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   */
  
  #ifndef	__LINUX_USB_COMPOSITE_H
  #define	__LINUX_USB_COMPOSITE_H
  
  /*
   * This framework is an optional layer on top of the USB Gadget interface,
   * making it easier to build (a) Composite devices, supporting multiple
   * functions within any single configuration, and (b) Multi-configuration
   * devices, also supporting multiple functions but without necessarily
   * having more than one function per configuration.
   *
   * Example:  a device with a single configuration supporting both network
   * link and mass storage functions is a composite device.  Those functions
   * might alternatively be packaged in individual configurations, but in
   * the composite model the host can use both functions at the same time.
   */
  
  #include <linux/usb/ch9.h>
  #include <linux/usb/gadget.h>
  
  /*
   * USB function drivers should return USB_GADGET_DELAYED_STATUS if they
   * wish to delay the data/status stages of the control transfer till they
   * are ready. The control transfer will then be kept from completing till
   * all the function drivers that requested for USB_GADGET_DELAYED_STAUS
   * invoke usb_composite_setup_continue().
   */
  #define USB_GADGET_DELAYED_STATUS       0x7fff	/* Impossibly large value */
  
  struct usb_configuration;
  
  /**
   * struct usb_function - describes one function of a configuration
   * @name: For diagnostics, identifies the function.
   * @strings: tables of strings, keyed by identifiers assigned during bind()
   *	and by language IDs provided in control requests
   * @descriptors: Table of full (or low) speed descriptors, using interface and
   *	string identifiers assigned during @bind().  If this pointer is null,
   *	the function will not be available at full speed (or at low speed).
   * @hs_descriptors: Table of high speed descriptors, using interface and
   *	string identifiers assigned during @bind().  If this pointer is null,
   *	the function will not be available at high speed.
   * @config: assigned when @usb_add_function() is called; this is the
   *	configuration with which this function is associated.
   * @bind: Before the gadget can register, all of its functions bind() to the
   *	available resources including string and interface identifiers used
   *	in interface or class descriptors; endpoints; I/O buffers; and so on.
   * @unbind: Reverses @bind; called as a side effect of unregistering the
   *	driver which added this function.
   * @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may
   *	initialize usb_ep.driver data at this time (when it is used).
   *	Note that setting an interface to its current altsetting resets
   *	interface state, and that all interfaces have a disabled state.
   * @get_alt: Returns the active altsetting.  If this is not provided,
   *	then only altsetting zero is supported.
   * @disable: (REQUIRED) Indicates the function should be disabled.  Reasons
   *	include host resetting or reconfiguring the gadget, and disconnection.
   * @setup: Used for interface-specific control requests.
   * @suspend: Notifies functions when the host stops sending USB traffic.
   * @resume: Notifies functions when the host restarts USB traffic.
   *
   * A single USB function uses one or more interfaces, and should in most
   * cases support operation at both full and high speeds.  Each function is
   * associated by @usb_add_function() with a one configuration; that function
   * causes @bind() to be called so resources can be allocated as part of
   * setting up a gadget driver.  Those resources include endpoints, which
   * should be allocated using @usb_ep_autoconfig().
   *
   * To support dual speed operation, a function driver provides descriptors
   * for both high and full speed operation.  Except in rare cases that don't
   * involve bulk endpoints, each speed needs different endpoint descriptors.
   *
   * Function drivers choose their own strategies for managing instance data.
   * The simplest strategy just declares it "static', which means the function
   * can only be activated once.  If the function needs to be exposed in more
   * than one configuration at a given speed, it needs to support multiple
   * usb_function structures (one for each configuration).
   *
   * A more complex strategy might encapsulate a @usb_function structure inside
   * a driver-specific instance structure to allows multiple activations.  An
   * example of multiple activations might be a CDC ACM function that supports
   * two or more distinct instances within the same configuration, providing
   * several independent logical data links to a USB host.
   */
  struct usb_function {
  	const char			*name;
  	struct usb_gadget_strings	**strings;
  	struct usb_descriptor_header	**descriptors;
  	struct usb_descriptor_header	**hs_descriptors;
  
  	struct usb_configuration	*config;
  
  	/* REVISIT:  bind() functions can be marked __init, which
  	 * makes trouble for section mismatch analysis.  See if
  	 * we can't restructure things to avoid mismatching.
  	 * Related:  unbind() may kfree() but bind() won't...
  	 */
  
  	/* configuration management:  bind/unbind */
  	int			(*bind)(struct usb_configuration *,
  					struct usb_function *);
  	void			(*unbind)(struct usb_configuration *,
  					struct usb_function *);
  
  	/* runtime state management */
  	int			(*set_alt)(struct usb_function *,
  					unsigned interface, unsigned alt);
  	int			(*get_alt)(struct usb_function *,
  					unsigned interface);
  	void			(*disable)(struct usb_function *);
  	int			(*setup)(struct usb_function *,
  					const struct usb_ctrlrequest *);
  	void			(*suspend)(struct usb_function *);
  	void			(*resume)(struct usb_function *);
  
  	/* private: */
  	/* internals */
  	struct list_head		list;
  	DECLARE_BITMAP(endpoints, 32);
  };
  
  int usb_add_function(struct usb_configuration *, struct usb_function *);
  
  int usb_function_deactivate(struct usb_function *);
  int usb_function_activate(struct usb_function *);
  
  int usb_interface_id(struct usb_configuration *, struct usb_function *);
  
  /**
   * ep_choose - select descriptor endpoint at current device speed
   * @g: gadget, connected and running at some speed
   * @hs: descriptor to use for high speed operation
   * @fs: descriptor to use for full or low speed operation
   */
  static inline struct usb_endpoint_descriptor *
  ep_choose(struct usb_gadget *g, struct usb_endpoint_descriptor *hs,
  		struct usb_endpoint_descriptor *fs)
  {
  	if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
  		return hs;
  	return fs;
  }
  
  #define	MAX_CONFIG_INTERFACES		16	/* arbitrary; max 255 */
  
  /**
   * struct usb_configuration - represents one gadget configuration
   * @label: For diagnostics, describes the configuration.
   * @strings: Tables of strings, keyed by identifiers assigned during @bind()
   *	and by language IDs provided in control requests.
   * @descriptors: Table of descriptors preceding all function descriptors.
   *	Examples include OTG and vendor-specific descriptors.
   * @unbind: Reverses @bind; called as a side effect of unregistering the
   *	driver which added this configuration.
   * @setup: Used to delegate control requests that aren't handled by standard
   *	device infrastructure or directed at a specific interface.
   * @bConfigurationValue: Copied into configuration descriptor.
   * @iConfiguration: Copied into configuration descriptor.
   * @bmAttributes: Copied into configuration descriptor.
   * @bMaxPower: Copied into configuration descriptor.
   * @cdev: assigned by @usb_add_config() before calling @bind(); this is
   *	the device associated with this configuration.
   *
   * Configurations are building blocks for gadget drivers structured around
   * function drivers.  Simple USB gadgets require only one function and one
   * configuration, and handle dual-speed hardware by always providing the same
   * functionality.  Slightly more complex gadgets may have more than one
   * single-function configuration at a given speed; or have configurations
   * that only work at one speed.
   *
   * Composite devices are, by definition, ones with configurations which
   * include more than one function.
   *
   * The lifecycle of a usb_configuration includes allocation, initialization
   * of the fields described above, and calling @usb_add_config() to set up
   * internal data and bind it to a specific device.  The configuration's
   * @bind() method is then used to initialize all the functions and then
   * call @usb_add_function() for them.
   *
   * Those functions would normally be independent of each other, but that's
   * not mandatory.  CDC WMC devices are an example where functions often
   * depend on other functions, with some functions subsidiary to others.
   * Such interdependency may be managed in any way, so long as all of the
   * descriptors complete by the time the composite driver returns from
   * its bind() routine.
   */
  struct usb_configuration {
  	const char			*label;
  	struct usb_gadget_strings	**strings;
  	const struct usb_descriptor_header **descriptors;
  
  	/* REVISIT:  bind() functions can be marked __init, which
  	 * makes trouble for section mismatch analysis.  See if
  	 * we can't restructure things to avoid mismatching...
  	 */
  
  	/* configuration management: unbind/setup */
  	void			(*unbind)(struct usb_configuration *);
  	int			(*setup)(struct usb_configuration *,
  					const struct usb_ctrlrequest *);
  
  	/* fields in the config descriptor */
  	u8			bConfigurationValue;
  	u8			iConfiguration;
  	u8			bmAttributes;
  	u8			bMaxPower;
  
  	struct usb_composite_dev	*cdev;
  
  	/* private: */
  	/* internals */
  	struct list_head	list;
  	struct list_head	functions;
  	u8			next_interface_id;
  	unsigned		highspeed:1;
  	unsigned		fullspeed:1;
  	struct usb_function	*interface[MAX_CONFIG_INTERFACES];
  };
  
  int usb_add_config(struct usb_composite_dev *,
  		struct usb_configuration *,
  		int (*)(struct usb_configuration *));
  
  /**
   * struct usb_composite_driver - groups configurations into a gadget
   * @name: For diagnostics, identifies the driver.
   * @iProduct: Used as iProduct override if @dev->iProduct is not set.
   *	If NULL value of @name is taken.
   * @iManufacturer: Used as iManufacturer override if @dev->iManufacturer is
   *	not set. If NULL a default "<system> <release> with <udc>" value
   *	will be used.
   * @dev: Template descriptor for the device, including default device
   *	identifiers.
   * @strings: tables of strings, keyed by identifiers assigned during bind()
   *	and language IDs provided in control requests
   * @needs_serial: set to 1 if the gadget needs userspace to provide
   * 	a serial number.  If one is not provided, warning will be printed.
   * @unbind: Reverses bind; called as a side effect of unregistering
   *	this driver.
   * @disconnect: optional driver disconnect method
   * @suspend: Notifies when the host stops sending USB traffic,
   *	after function notifications
   * @resume: Notifies configuration when the host restarts USB traffic,
   *	before function notifications
   *
   * Devices default to reporting self powered operation.  Devices which rely
   * on bus powered operation should report this in their @bind() method.
   *
   * Before returning from bind, various fields in the template descriptor
   * may be overridden.  These include the idVendor/idProduct/bcdDevice values
   * normally to bind the appropriate host side driver, and the three strings
   * (iManufacturer, iProduct, iSerialNumber) normally used to provide user
   * meaningful device identifiers.  (The strings will not be defined unless
   * they are defined in @dev and @strings.)  The correct ep0 maxpacket size
   * is also reported, as defined by the underlying controller driver.
   */
  struct usb_composite_driver {
  	const char				*name;
  	const char				*iProduct;
  	const char				*iManufacturer;
  	const struct usb_device_descriptor	*dev;
  	struct usb_gadget_strings		**strings;
  	unsigned		needs_serial:1;
  
  	int			(*unbind)(struct usb_composite_dev *);
  
  	void			(*disconnect)(struct usb_composite_dev *);
  
  	/* global suspend hooks */
  	void			(*suspend)(struct usb_composite_dev *);
  	void			(*resume)(struct usb_composite_dev *);
  };
  
  extern int usb_composite_probe(struct usb_composite_driver *driver,
  			       int (*bind)(struct usb_composite_dev *cdev));
  extern void usb_composite_unregister(struct usb_composite_driver *driver);
  extern void usb_composite_setup_continue(struct usb_composite_dev *cdev);
  
  
  /**
   * struct usb_composite_device - represents one composite usb gadget
   * @gadget: read-only, abstracts the gadget's usb peripheral controller
   * @req: used for control responses; buffer is pre-allocated
   * @bufsiz: size of buffer pre-allocated in @req
   * @config: the currently active configuration
   *
   * One of these devices is allocated and initialized before the
   * associated device driver's bind() is called.
   *
   * OPEN ISSUE:  it appears that some WUSB devices will need to be
   * built by combining a normal (wired) gadget with a wireless one.
   * This revision of the gadget framework should probably try to make
   * sure doing that won't hurt too much.
   *
   * One notion for how to handle Wireless USB devices involves:
   * (a) a second gadget here, discovery mechanism TBD, but likely
   *     needing separate "register/unregister WUSB gadget" calls;
   * (b) updates to usb_gadget to include flags "is it wireless",
   *     "is it wired", plus (presumably in a wrapper structure)
   *     bandgroup and PHY info;
   * (c) presumably a wireless_ep wrapping a usb_ep, and reporting
   *     wireless-specific parameters like maxburst and maxsequence;
   * (d) configurations that are specific to wireless links;
   * (e) function drivers that understand wireless configs and will
   *     support wireless for (additional) function instances;
   * (f) a function to support association setup (like CBAF), not
   *     necessarily requiring a wireless adapter;
   * (g) composite device setup that can create one or more wireless
   *     configs, including appropriate association setup support;
   * (h) more, TBD.
   */
  struct usb_composite_dev {
  	struct usb_gadget		*gadget;
  	struct usb_request		*req;
  	unsigned			bufsiz;
  
  	struct usb_configuration	*config;
  
  	/* private: */
  	/* internals */
  	unsigned int			suspended:1;
  	struct usb_device_descriptor	desc;
  	struct list_head		configs;
  	struct usb_composite_driver	*driver;
  	u8				next_string_id;
  	u8				manufacturer_override;
  	u8				product_override;
  	u8				serial_override;
  
  	/* the gadget driver won't enable the data pullup
  	 * while the deactivation count is nonzero.
  	 */
  	unsigned			deactivations;
  
  	/* the composite driver won't complete the control transfer's
  	 * data/status stages till delayed_status is zero.
  	 */
  	int				delayed_status;
  
  	/* protects deactivations and delayed_status counts*/
  	spinlock_t			lock;
  };
  
  extern int usb_string_id(struct usb_composite_dev *c);
  extern int usb_string_ids_tab(struct usb_composite_dev *c,
  			      struct usb_string *str);
  extern int usb_string_ids_n(struct usb_composite_dev *c, unsigned n);
  
  
  /* messaging utils */
  #define DBG(d, fmt, args...) \
  	dev_dbg(&(d)->gadget->dev , fmt , ## args)
  #define VDBG(d, fmt, args...) \
  	dev_vdbg(&(d)->gadget->dev , fmt , ## args)
  #define ERROR(d, fmt, args...) \
  	dev_err(&(d)->gadget->dev , fmt , ## args)
  #define WARNING(d, fmt, args...) \
  	dev_warn(&(d)->gadget->dev , fmt , ## args)
  #define INFO(d, fmt, args...) \
  	dev_info(&(d)->gadget->dev , fmt , ## args)
  
  #endif	/* __LINUX_USB_COMPOSITE_H */
  