/*
 * 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;
        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 */