/*
   * 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/bcd.h>
  #include <linux/version.h>
  #include <linux/usb/ch9.h>
  #include <linux/usb/gadget.h>
  #include <linux/log2.h>
  #include <linux/configfs.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 */
  
  /* big enough to hold our biggest descriptor */
  #define USB_COMP_EP0_BUFSIZ	1024
  
  #define USB_MS_TO_HS_INTERVAL(x)	(ilog2((x * 1000 / 125)) + 1)
  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
   * @fs_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.
   * @ss_descriptors: Table of super speed descriptors, using interface and
   *	string identifiers assigned during @bind(). If this
   *	pointer is null after initiation, the function will not
   *	be available at super 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.
   * @free_func: free the struct usb_function.
   * @mod: (internal) points to the module that created this structure.
   * @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.
   * @get_status: Returns function status as a reply to
   *	GetStatus() request when the recepient is Interface.
   * @func_suspend: callback to be called when
   *	SetFeature(FUNCTION_SUSPEND) is reseived
   *
   * 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	**fs_descriptors;
  	struct usb_descriptor_header	**hs_descriptors;
  	struct usb_descriptor_header	**ss_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 *);
  	void			(*free_func)(struct usb_function *f);
  	struct module		*mod;
  
  	/* 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 *);
  
  	/* USB 3.0 additions */
  	int			(*get_status)(struct usb_function *);
  	int			(*func_suspend)(struct usb_function *,
  						u8 suspend_opt);
  	/* private: */
  	/* internals */
  	struct list_head		list;
  	DECLARE_BITMAP(endpoints, 32);
  	const struct usb_function_instance *fi;
  };
  
  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 *);
  
  int config_ep_by_speed(struct usb_gadget *g, struct usb_function *f,
  			struct usb_ep *_ep);
  
  #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.
   * @MaxPower: Power consumtion in mA. Used to compute bMaxPower in the
   *	configuration descriptor after considering the bus speed.
   * @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;
  	u16			MaxPower;
  
  	struct usb_composite_dev	*cdev;
  
  	/* private: */
  	/* internals */
  	struct list_head	list;
  	struct list_head	functions;
  	u8			next_interface_id;
  	unsigned		superspeed:1;
  	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 *));
  
  void usb_remove_config(struct usb_composite_dev *,
  		struct usb_configuration *);
  
  /* predefined index for usb_composite_driver */
  enum {
  	USB_GADGET_MANUFACTURER_IDX	= 0,
  	USB_GADGET_PRODUCT_IDX,
  	USB_GADGET_SERIAL_IDX,
  	USB_GADGET_FIRST_AVAIL_IDX,
  };
  
  /**
   * struct usb_composite_driver - groups configurations into a gadget
   * @name: For diagnostics, identifies the driver.
   * @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. Note: The first entries
   *	are predefined. The first entry that may be used is
   *	USB_GADGET_FIRST_AVAIL_IDX
   * @max_speed: Highest speed the driver supports.
   * @needs_serial: set to 1 if the gadget needs userspace to provide
   * 	a serial number.  If one is not provided, warning will be printed.
   * @bind: (REQUIRED) Used to allocate resources that are shared across the
   *	whole device, such as string IDs, and add its configurations using
   *	@usb_add_config(). This may fail by returning a negative errno
   *	value; it should return zero on successful initialization.
   * @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
   * @gadget_driver: Gadget driver controlling this driver
   *
   * 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 struct usb_device_descriptor	*dev;
  	struct usb_gadget_strings		**strings;
  	enum usb_device_speed			max_speed;
  	unsigned		needs_serial:1;
  
  	int			(*bind)(struct usb_composite_dev *cdev);
  	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 *);
  	struct usb_gadget_driver		gadget_driver;
  };
  
  extern int usb_composite_probe(struct usb_composite_driver *driver);
  extern void usb_composite_unregister(struct usb_composite_driver *driver);
  extern void usb_composite_setup_continue(struct usb_composite_dev *cdev);
  extern int composite_dev_prepare(struct usb_composite_driver *composite,
  		struct usb_composite_dev *cdev);
  void composite_dev_cleanup(struct usb_composite_dev *cdev);
  
  static inline struct usb_composite_driver *to_cdriver(
  		struct usb_gadget_driver *gdrv)
  {
  	return container_of(gdrv, struct usb_composite_driver, gadget_driver);
  }
  
  /**
   * 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
   * @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;
  
  	struct usb_configuration	*config;
  
  	/* private: */
  	/* internals */
  	unsigned int			suspended:1;
  	struct usb_device_descriptor	desc;
  	struct list_head		configs;
  	struct list_head		gstrings;
  	struct usb_composite_driver	*driver;
  	u8				next_string_id;
  	char				*def_manufacturer;
  
  	/* 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 struct usb_string *usb_gstrings_attach(struct usb_composite_dev *cdev,
  		struct usb_gadget_strings **sp, unsigned n_strings);
  
  extern int usb_string_ids_n(struct usb_composite_dev *c, unsigned n);
  
  extern void composite_disconnect(struct usb_gadget *gadget);
  extern int composite_setup(struct usb_gadget *gadget,
  		const struct usb_ctrlrequest *ctrl);
  
  /*
   * Some systems will need runtime overrides for the  product identifiers
   * published in the device descriptor, either numbers or strings or both.
   * String parameters are in UTF-8 (superset of ASCII's 7 bit characters).
   */
  struct usb_composite_overwrite {
  	u16	idVendor;
  	u16	idProduct;
  	u16	bcdDevice;
  	char	*serial_number;
  	char	*manufacturer;
  	char	*product;
  };
  #define USB_GADGET_COMPOSITE_OPTIONS()					\
  	static struct usb_composite_overwrite coverwrite;		\
  									\
  	module_param_named(idVendor, coverwrite.idVendor, ushort, S_IRUGO); \
  	MODULE_PARM_DESC(idVendor, "USB Vendor ID");			\
  									\
  	module_param_named(idProduct, coverwrite.idProduct, ushort, S_IRUGO); \
  	MODULE_PARM_DESC(idProduct, "USB Product ID");			\
  									\
  	module_param_named(bcdDevice, coverwrite.bcdDevice, ushort, S_IRUGO); \
  	MODULE_PARM_DESC(bcdDevice, "USB Device version (BCD)");	\
  									\
  	module_param_named(iSerialNumber, coverwrite.serial_number, charp, \
  			S_IRUGO); \
  	MODULE_PARM_DESC(iSerialNumber, "SerialNumber string");		\
  									\
  	module_param_named(iManufacturer, coverwrite.manufacturer, charp, \
  			S_IRUGO); \
  	MODULE_PARM_DESC(iManufacturer, "USB Manufacturer string");	\
  									\
  	module_param_named(iProduct, coverwrite.product, charp, S_IRUGO); \
  	MODULE_PARM_DESC(iProduct, "USB Product string")
  
  void usb_composite_overwrite_options(struct usb_composite_dev *cdev,
  		struct usb_composite_overwrite *covr);
  
  static inline u16 get_default_bcdDevice(void)
  {
  	u16 bcdDevice;
  
  	bcdDevice = bin2bcd((LINUX_VERSION_CODE >> 16 & 0xff)) << 8;
  	bcdDevice |= bin2bcd((LINUX_VERSION_CODE >> 8 & 0xff));
  	return bcdDevice;
  }
  
  struct usb_function_driver {
  	const char *name;
  	struct module *mod;
  	struct list_head list;
  	struct usb_function_instance *(*alloc_inst)(void);
  	struct usb_function *(*alloc_func)(struct usb_function_instance *inst);
  };
  
  struct usb_function_instance {
  	struct config_group group;
  	struct list_head cfs_list;
  	struct usb_function_driver *fd;
  	int (*set_inst_name)(struct usb_function_instance *inst,
  			      const char *name);
  	void (*free_func_inst)(struct usb_function_instance *inst);
  };
  
  void usb_function_unregister(struct usb_function_driver *f);
  int usb_function_register(struct usb_function_driver *newf);
  void usb_put_function_instance(struct usb_function_instance *fi);
  void usb_put_function(struct usb_function *f);
  struct usb_function_instance *usb_get_function_instance(const char *name);
  struct usb_function *usb_get_function(struct usb_function_instance *fi);
  
  struct usb_configuration *usb_get_config(struct usb_composite_dev *cdev,
  		int val);
  int usb_add_config_only(struct usb_composite_dev *cdev,
  		struct usb_configuration *config);
  void usb_remove_function(struct usb_configuration *c, struct usb_function *f);
  
  #define DECLARE_USB_FUNCTION(_name, _inst_alloc, _func_alloc)		\
  	static struct usb_function_driver _name ## usb_func = {		\
  		.name = __stringify(_name),				\
  		.mod  = THIS_MODULE,					\
  		.alloc_inst = _inst_alloc,				\
  		.alloc_func = _func_alloc,				\
  	};								\
  	MODULE_ALIAS("usbfunc:"__stringify(_name));
  
  #define DECLARE_USB_FUNCTION_INIT(_name, _inst_alloc, _func_alloc)	\
  	DECLARE_USB_FUNCTION(_name, _inst_alloc, _func_alloc)		\
  	static int __init _name ## mod_init(void)			\
  	{								\
  		return usb_function_register(&_name ## usb_func);	\
  	}								\
  	static void __exit _name ## mod_exit(void)			\
  	{								\
  		usb_function_unregister(&_name ## usb_func);		\
  	}								\
  	module_init(_name ## mod_init);					\
  	module_exit(_name ## mod_exit)
  
  /* 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 */