include/linux/usb/composite.h

   1 /*
   2  * composite.h -- framework for usb gadgets which are composite devices
   3  *
   4  * Copyright (C) 2006-2008 David Brownell
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  */
  20
  21 #ifndef __LINUX_USB_COMPOSITE_H
  22 #define __LINUX_USB_COMPOSITE_H
  23
  24 /*
  25  * This framework is an optional layer on top of the USB Gadget interface,
  26  * making it easier to build (a) Composite devices, supporting multiple
  27  * functions within any single configuration, and (b) Multi-configuration
  28  * devices, also supporting multiple functions but without necessarily
  29  * having more than one function per configuration.
  30  *
  31  * Example:  a device with a single configuration supporting both network
  32  * link and mass storage functions is a composite device.  Those functions
  33  * might alternatively be packaged in individual configurations, but in
  34  * the composite model the host can use both functions at the same time.
  35  */
  36
  37 #include <linux/usb/ch9.h>
  38 #include <linux/usb/gadget.h>
  39
  40 /*
  41  * USB function drivers should return USB_GADGET_DELAYED_STATUS if they
  42  * wish to delay the data/status stages of the control transfer till they
  43  * are ready. The control transfer will then be kept from completing till
  44  * all the function drivers that requested for USB_GADGET_DELAYED_STAUS
  45  * invoke usb_composite_setup_continue().
  46  */
  47 #define USB_GADGET_DELAYED_STATUS       0x7fff  /* Impossibly large value */
  48
  49 struct usb_configuration;
  50
  51 /**
  52  * struct usb_function - describes one function of a configuration
  53  * @name: For diagnostics, identifies the function.
  54  * @strings: tables of strings, keyed by identifiers assigned during bind()
  55  *      and by language IDs provided in control requests
  56  * @descriptors: Table of full (or low) speed descriptors, using interface and
  57  *      string identifiers assigned during @bind().  If this pointer is null,
  58  *      the function will not be available at full speed (or at low speed).
  59  * @hs_descriptors: Table of high speed descriptors, using interface and
  60  *      string identifiers assigned during @bind().  If this pointer is null,
  61  *      the function will not be available at high speed.
  62  * @config: assigned when @usb_add_function() is called; this is the
  63  *      configuration with which this function is associated.
  64  * @bind: Before the gadget can register, all of its functions bind() to the
  65  *      available resources including string and interface identifiers used
  66  *      in interface or class descriptors; endpoints; I/O buffers; and so on.
  67  * @unbind: Reverses @bind; called as a side effect of unregistering the
  68  *      driver which added this function.
  69  * @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may
  70  *      initialize usb_ep.driver data at this time (when it is used).
  71  *      Note that setting an interface to its current altsetting resets
  72  *      interface state, and that all interfaces have a disabled state.
  73  * @get_alt: Returns the active altsetting.  If this is not provided,
  74  *      then only altsetting zero is supported.
  75  * @disable: (REQUIRED) Indicates the function should be disabled.  Reasons
  76  *      include host resetting or reconfiguring the gadget, and disconnection.
  77  * @setup: Used for interface-specific control requests.
  78  * @suspend: Notifies functions when the host stops sending USB traffic.
  79  * @resume: Notifies functions when the host restarts USB traffic.
  80  *
  81  * A single USB function uses one or more interfaces, and should in most
  82  * cases support operation at both full and high speeds.  Each function is
  83  * associated by @usb_add_function() with a one configuration; that function
  84  * causes @bind() to be called so resources can be allocated as part of
  85  * setting up a gadget driver.  Those resources include endpoints, which
  86  * should be allocated using @usb_ep_autoconfig().
  87  *
  88  * To support dual speed operation, a function driver provides descriptors
  89  * for both high and full speed operation.  Except in rare cases that don't
  90  * involve bulk endpoints, each speed needs different endpoint descriptors.
  91  *
  92  * Function drivers choose their own strategies for managing instance data.
  93  * The simplest strategy just declares it "static', which means the function
  94  * can only be activated once.  If the function needs to be exposed in more
  95  * than one configuration at a given speed, it needs to support multiple
  96  * usb_function structures (one for each configuration).
  97  *
  98  * A more complex strategy might encapsulate a @usb_function structure inside
  99  * a driver-specific instance structure to allows multiple activations.  An
 100  * example of multiple activations might be a CDC ACM function that supports
 101  * two or more distinct instances within the same configuration, providing
 102  * several independent logical data links to a USB host.
 103  */
 104 struct usb_function {
 105         const char                      *name;
 106         struct usb_gadget_strings       **strings;
 107         struct usb_descriptor_header    **descriptors;
 108         struct usb_descriptor_header    **hs_descriptors;
 109
 110         struct usb_configuration        *config;
 111
 112         /* REVISIT:  bind() functions can be marked __init, which
 113          * makes trouble for section mismatch analysis.  See if
 114          * we can't restructure things to avoid mismatching.
 115          * Related:  unbind() may kfree() but bind() won't...
 116          */
 117
 118         /* configuration management:  bind/unbind */
 119         int                     (*bind)(struct usb_configuration *,
 120                                         struct usb_function *);
 121         void                    (*unbind)(struct usb_configuration *,
 122                                         struct usb_function *);
 123
 124         /* runtime state management */
 125         int                     (*set_alt)(struct usb_function *,
 126                                         unsigned interface, unsigned alt);
 127         int                     (*get_alt)(struct usb_function *,
 128                                         unsigned interface);
 129         void                    (*disable)(struct usb_function *);
 130         int                     (*setup)(struct usb_function *,
 131                                         const struct usb_ctrlrequest *);
 132         void                    (*suspend)(struct usb_function *);
 133         void                    (*resume)(struct usb_function *);
 134
 135         /* private: */
 136         /* internals */
 137         struct list_head                list;
 138         DECLARE_BITMAP(endpoints, 32);
 139 };
 140
 141 int usb_add_function(struct usb_configuration *, struct usb_function *);
 142
 143 int usb_function_deactivate(struct usb_function *);
 144 int usb_function_activate(struct usb_function *);
 145
 146 int usb_interface_id(struct usb_configuration *, struct usb_function *);
 147
 148 /**
 149  * ep_choose - select descriptor endpoint at current device speed
 150  * @g: gadget, connected and running at some speed
 151  * @hs: descriptor to use for high speed operation
 152  * @fs: descriptor to use for full or low speed operation
 153  */
 154 static inline struct usb_endpoint_descriptor *
 155 ep_choose(struct usb_gadget *g, struct usb_endpoint_descriptor *hs,
 156                 struct usb_endpoint_descriptor *fs)
 157 {
 158         if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
 159                 return hs;
 160         return fs;
 161 }
 162
 163 #define MAX_CONFIG_INTERFACES           16      /* arbitrary; max 255 */
 164
 165 /**
 166  * struct usb_configuration - represents one gadget configuration
 167  * @label: For diagnostics, describes the configuration.
 168  * @strings: Tables of strings, keyed by identifiers assigned during @bind()
 169  *      and by language IDs provided in control requests.
 170  * @descriptors: Table of descriptors preceding all function descriptors.
 171  *      Examples include OTG and vendor-specific descriptors.
 172  * @unbind: Reverses @bind; called as a side effect of unregistering the
 173  *      driver which added this configuration.
 174  * @setup: Used to delegate control requests that aren't handled by standard
 175  *      device infrastructure or directed at a specific interface.
 176  * @bConfigurationValue: Copied into configuration descriptor.
 177  * @iConfiguration: Copied into configuration descriptor.
 178  * @bmAttributes: Copied into configuration descriptor.
 179  * @bMaxPower: Copied into configuration descriptor.
 180  * @cdev: assigned by @usb_add_config() before calling @bind(); this is
 181  *      the device associated with this configuration.
 182  *
 183  * Configurations are building blocks for gadget drivers structured around
 184  * function drivers.  Simple USB gadgets require only one function and one
 185  * configuration, and handle dual-speed hardware by always providing the same
 186  * functionality.  Slightly more complex gadgets may have more than one
 187  * single-function configuration at a given speed; or have configurations
 188  * that only work at one speed.
 189  *
 190  * Composite devices are, by definition, ones with configurations which
 191  * include more than one function.
 192  *
 193  * The lifecycle of a usb_configuration includes allocation, initialization
 194  * of the fields described above, and calling @usb_add_config() to set up
 195  * internal data and bind it to a specific device.  The configuration's
 196  * @bind() method is then used to initialize all the functions and then
 197  * call @usb_add_function() for them.
 198  *
 199  * Those functions would normally be independent of each other, but that's
 200  * not mandatory.  CDC WMC devices are an example where functions often
 201  * depend on other functions, with some functions subsidiary to others.
 202  * Such interdependency may be managed in any way, so long as all of the
 203  * descriptors complete by the time the composite driver returns from
 204  * its bind() routine.
 205  */
 206 struct usb_configuration {
 207         const char                      *label;
 208         struct usb_gadget_strings       **strings;
 209         const struct usb_descriptor_header **descriptors;
 210
 211         /* REVISIT:  bind() functions can be marked __init, which
 212          * makes trouble for section mismatch analysis.  See if
 213          * we can't restructure things to avoid mismatching...
 214          */
 215
 216         /* configuration management: unbind/setup */
 217         void                    (*unbind)(struct usb_configuration *);
 218         int                     (*setup)(struct usb_configuration *,
 219                                         const struct usb_ctrlrequest *);
 220
 221         /* fields in the config descriptor */
 222         u8                      bConfigurationValue;
 223         u8                      iConfiguration;
 224         u8                      bmAttributes;
 225         u8                      bMaxPower;
 226
 227         struct usb_composite_dev        *cdev;
 228
 229         /* private: */
 230         /* internals */
 231         struct list_head        list;
 232         struct list_head        functions;
 233         u8                      next_interface_id;
 234         unsigned                highspeed:1;
 235         unsigned                fullspeed:1;
 236         struct usb_function     *interface[MAX_CONFIG_INTERFACES];
 237 };
 238
 239 int usb_add_config(struct usb_composite_dev *,
 240                 struct usb_configuration *,
 241                 int (*)(struct usb_configuration *));
 242
 243 /**
 244  * struct usb_composite_driver - groups configurations into a gadget
 245  * @name: For diagnostics, identifies the driver.
 246  * @iProduct: Used as iProduct override if @dev->iProduct is not set.
 247  *      If NULL value of @name is taken.
 248  * @iManufacturer: Used as iManufacturer override if @dev->iManufacturer is
 249  *      not set. If NULL a default "<system> <release> with <udc>" value
 250  *      will be used.
 251  * @dev: Template descriptor for the device, including default device
 252  *      identifiers.
 253  * @strings: tables of strings, keyed by identifiers assigned during bind()
 254  *      and language IDs provided in control requests
 255  * @needs_serial: set to 1 if the gadget needs userspace to provide
 256  *      a serial number.  If one is not provided, warning will be printed.
 257  * @unbind: Reverses bind; called as a side effect of unregistering
 258  *      this driver.
 259  * @disconnect: optional driver disconnect method
 260  * @suspend: Notifies when the host stops sending USB traffic,
 261  *      after function notifications
 262  * @resume: Notifies configuration when the host restarts USB traffic,
 263  *      before function notifications
 264  *
 265  * Devices default to reporting self powered operation.  Devices which rely
 266  * on bus powered operation should report this in their @bind() method.
 267  *
 268  * Before returning from bind, various fields in the template descriptor
 269  * may be overridden.  These include the idVendor/idProduct/bcdDevice values
 270  * normally to bind the appropriate host side driver, and the three strings
 271  * (iManufacturer, iProduct, iSerialNumber) normally used to provide user
 272  * meaningful device identifiers.  (The strings will not be defined unless
 273  * they are defined in @dev and @strings.)  The correct ep0 maxpacket size
 274  * is also reported, as defined by the underlying controller driver.
 275  */
 276 struct usb_composite_driver {
 277         const char                              *name;
 278         const char                              *iProduct;
 279         const char                              *iManufacturer;
 280         const struct usb_device_descriptor      *dev;
 281         struct usb_gadget_strings               **strings;
 282         unsigned                needs_serial:1;
 283
 284         int                     (*unbind)(struct usb_composite_dev *);
 285
 286         void                    (*disconnect)(struct usb_composite_dev *);
 287
 288         /* global suspend hooks */
 289         void                    (*suspend)(struct usb_composite_dev *);
 290         void                    (*resume)(struct usb_composite_dev *);
 291 };
 292
 293 extern int usb_composite_probe(struct usb_composite_driver *driver,
 294                                int (*bind)(struct usb_composite_dev *cdev));
 295 extern void usb_composite_unregister(struct usb_composite_driver *driver);
 296 extern void usb_composite_setup_continue(struct usb_composite_dev *cdev);
 297
 298
 299 /**
 300  * struct usb_composite_device - represents one composite usb gadget
 301  * @gadget: read-only, abstracts the gadget's usb peripheral controller
 302  * @req: used for control responses; buffer is pre-allocated
 303  * @bufsiz: size of buffer pre-allocated in @req
 304  * @config: the currently active configuration
 305  *
 306  * One of these devices is allocated and initialized before the
 307  * associated device driver's bind() is called.
 308  *
 309  * OPEN ISSUE:  it appears that some WUSB devices will need to be
 310  * built by combining a normal (wired) gadget with a wireless one.
 311  * This revision of the gadget framework should probably try to make
 312  * sure doing that won't hurt too much.
 313  *
 314  * One notion for how to handle Wireless USB devices involves:
 315  * (a) a second gadget here, discovery mechanism TBD, but likely
 316  *     needing separate "register/unregister WUSB gadget" calls;
 317  * (b) updates to usb_gadget to include flags "is it wireless",
 318  *     "is it wired", plus (presumably in a wrapper structure)
 319  *     bandgroup and PHY info;
 320  * (c) presumably a wireless_ep wrapping a usb_ep, and reporting
 321  *     wireless-specific parameters like maxburst and maxsequence;
 322  * (d) configurations that are specific to wireless links;
 323  * (e) function drivers that understand wireless configs and will
 324  *     support wireless for (additional) function instances;
 325  * (f) a function to support association setup (like CBAF), not
 326  *     necessarily requiring a wireless adapter;
 327  * (g) composite device setup that can create one or more wireless
 328  *     configs, including appropriate association setup support;
 329  * (h) more, TBD.
 330  */
 331 struct usb_composite_dev {
 332         struct usb_gadget               *gadget;
 333         struct usb_request              *req;
 334         unsigned                        bufsiz;
 335
 336         struct usb_configuration        *config;
 337
 338         /* private: */
 339         /* internals */
 340         unsigned int                    suspended:1;
 341         struct usb_device_descriptor    desc;
 342         struct list_head                configs;
 343         struct usb_composite_driver     *driver;
 344         u8                              next_string_id;
 345         u8                              manufacturer_override;
 346         u8                              product_override;
 347         u8                              serial_override;
 348
 349         /* the gadget driver won't enable the data pullup
 350          * while the deactivation count is nonzero.
 351          */
 352         unsigned                        deactivations;
 353
 354         /* the composite driver won't complete the control transfer's
 355          * data/status stages till delayed_status is zero.
 356          */
 357         int                             delayed_status;
 358
 359         /* protects deactivations and delayed_status counts*/
 360         spinlock_t                      lock;
 361 };
 362
 363 extern int usb_string_id(struct usb_composite_dev *c);
 364 extern int usb_string_ids_tab(struct usb_composite_dev *c,
 365                               struct usb_string *str);
 366 extern int usb_string_ids_n(struct usb_composite_dev *c, unsigned n);
 367
 368
 369 /* messaging utils */
 370 #define DBG(d, fmt, args...) \
 371         dev_dbg(&(d)->gadget->dev , fmt , ## args)
 372 #define VDBG(d, fmt, args...) \
 373         dev_vdbg(&(d)->gadget->dev , fmt , ## args)
 374 #define ERROR(d, fmt, args...) \
 375         dev_err(&(d)->gadget->dev , fmt , ## args)
 376 #define WARNING(d, fmt, args...) \
 377         dev_warn(&(d)->gadget->dev , fmt , ## args)
 378 #define INFO(d, fmt, args...) \
 379         dev_info(&(d)->gadget->dev , fmt , ## args)
 380
 381 #endif  /* __LINUX_USB_COMPOSITE_H */