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 <common.h> 38 #include <linux/usb/ch9.h> 39 #include <linux/usb/gadget.h> 40 #include <usb/lin_gadget_compat.h> 41 42 struct usb_configuration; 43 44 /** 45 * struct usb_function - describes one function of a configuration 46 * @name: For diagnostics, identifies the function. 47 * @strings: tables of strings, keyed by identifiers assigned during bind() 48 * and by language IDs provided in control requests 49 * @descriptors: Table of full (or low) speed descriptors, using interface and 50 * string identifiers assigned during @bind(). If this pointer is null, 51 * the function will not be available at full speed (or at low speed). 52 * @hs_descriptors: Table of high speed descriptors, using interface and 53 * string identifiers assigned during @bind(). If this pointer is null, 54 * the function will not be available at high speed. 55 * @config: assigned when @usb_add_function() is called; this is the 56 * configuration with which this function is associated. 57 * @bind: Before the gadget can register, all of its functions bind() to the 58 * available resources including string and interface identifiers used 59 * in interface or class descriptors; endpoints; I/O buffers; and so on. 60 * @unbind: Reverses @bind; called as a side effect of unregistering the 61 * driver which added this function. 62 * @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may 63 * initialize usb_ep.driver data at this time (when it is used). 64 * Note that setting an interface to its current altsetting resets 65 * interface state, and that all interfaces have a disabled state. 66 * @get_alt: Returns the active altsetting. If this is not provided, 67 * then only altsetting zero is supported. 68 * @disable: (REQUIRED) Indicates the function should be disabled. Reasons 69 * include host resetting or reconfiguring the gadget, and disconnection. 70 * @setup: Used for interface-specific control requests. 71 * @suspend: Notifies functions when the host stops sending USB traffic. 72 * @resume: Notifies functions when the host restarts USB traffic. 73 * 74 * A single USB function uses one or more interfaces, and should in most 75 * cases support operation at both full and high speeds. Each function is 76 * associated by @usb_add_function() with a one configuration; that function 77 * causes @bind() to be called so resources can be allocated as part of 78 * setting up a gadget driver. Those resources include endpoints, which 79 * should be allocated using @usb_ep_autoconfig(). 80 * 81 * To support dual speed operation, a function driver provides descriptors 82 * for both high and full speed operation. Except in rare cases that don't 83 * involve bulk endpoints, each speed needs different endpoint descriptors. 84 * 85 * Function drivers choose their own strategies for managing instance data. 86 * The simplest strategy just declares it "static', which means the function 87 * can only be activated once. If the function needs to be exposed in more 88 * than one configuration at a given speed, it needs to support multiple 89 * usb_function structures (one for each configuration). 90 * 91 * A more complex strategy might encapsulate a @usb_function structure inside 92 * a driver-specific instance structure to allows multiple activations. An 93 * example of multiple activations might be a CDC ACM function that supports 94 * two or more distinct instances within the same configuration, providing 95 * several independent logical data links to a USB host. 96 */ 97 struct usb_function { 98 const char *name; 99 struct usb_gadget_strings **strings; 100 struct usb_descriptor_header **descriptors; 101 struct usb_descriptor_header **hs_descriptors; 102 103 struct usb_configuration *config; 104 105 /* REVISIT: bind() functions can be marked __init, which 106 * makes trouble for section mismatch analysis. See if 107 * we can't restructure things to avoid mismatching. 108 * Related: unbind() may kfree() but bind() won't... 109 */ 110 111 /* configuration management: bind/unbind */ 112 int (*bind)(struct usb_configuration *, 113 struct usb_function *); 114 void (*unbind)(struct usb_configuration *, 115 struct usb_function *); 116 117 /* runtime state management */ 118 int (*set_alt)(struct usb_function *, 119 unsigned interface, unsigned alt); 120 int (*get_alt)(struct usb_function *, 121 unsigned interface); 122 void (*disable)(struct usb_function *); 123 int (*setup)(struct usb_function *, 124 const struct usb_ctrlrequest *); 125 void (*suspend)(struct usb_function *); 126 void (*resume)(struct usb_function *); 127 128 /* private: */ 129 /* internals */ 130 struct list_head list; 131 DECLARE_BITMAP(endpoints, 32); 132 }; 133 134 int usb_add_function(struct usb_configuration *, struct usb_function *); 135 136 int usb_function_deactivate(struct usb_function *); 137 int usb_function_activate(struct usb_function *); 138 139 int usb_interface_id(struct usb_configuration *, struct usb_function *); 140 141 /** 142 * ep_choose - select descriptor endpoint at current device speed 143 * @g: gadget, connected and running at some speed 144 * @hs: descriptor to use for high speed operation 145 * @fs: descriptor to use for full or low speed operation 146 */ 147 static inline struct usb_endpoint_descriptor * 148 ep_choose(struct usb_gadget *g, struct usb_endpoint_descriptor *hs, 149 struct usb_endpoint_descriptor *fs) 150 { 151 if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH) 152 return hs; 153 return fs; 154 } 155 156 #define MAX_CONFIG_INTERFACES 16 /* arbitrary; max 255 */ 157 158 /** 159 * struct usb_configuration - represents one gadget configuration 160 * @label: For diagnostics, describes the configuration. 161 * @strings: Tables of strings, keyed by identifiers assigned during @bind() 162 * and by language IDs provided in control requests. 163 * @descriptors: Table of descriptors preceding all function descriptors. 164 * Examples include OTG and vendor-specific descriptors. 165 * @bind: Called from @usb_add_config() to allocate resources unique to this 166 * configuration and to call @usb_add_function() for each function used. 167 * @unbind: Reverses @bind; called as a side effect of unregistering the 168 * driver which added this configuration. 169 * @setup: Used to delegate control requests that aren't handled by standard 170 * device infrastructure or directed at a specific interface. 171 * @bConfigurationValue: Copied into configuration descriptor. 172 * @iConfiguration: Copied into configuration descriptor. 173 * @bmAttributes: Copied into configuration descriptor. 174 * @bMaxPower: Copied into configuration descriptor. 175 * @cdev: assigned by @usb_add_config() before calling @bind(); this is 176 * the device associated with this configuration. 177 * 178 * Configurations are building blocks for gadget drivers structured around 179 * function drivers. Simple USB gadgets require only one function and one 180 * configuration, and handle dual-speed hardware by always providing the same 181 * functionality. Slightly more complex gadgets may have more than one 182 * single-function configuration at a given speed; or have configurations 183 * that only work at one speed. 184 * 185 * Composite devices are, by definition, ones with configurations which 186 * include more than one function. 187 * 188 * The lifecycle of a usb_configuration includes allocation, initialization 189 * of the fields described above, and calling @usb_add_config() to set up 190 * internal data and bind it to a specific device. The configuration's 191 * @bind() method is then used to initialize all the functions and then 192 * call @usb_add_function() for them. 193 * 194 * Those functions would normally be independant of each other, but that's 195 * not mandatory. CDC WMC devices are an example where functions often 196 * depend on other functions, with some functions subsidiary to others. 197 * Such interdependency may be managed in any way, so long as all of the 198 * descriptors complete by the time the composite driver returns from 199 * its bind() routine. 200 */ 201 struct usb_configuration { 202 const char *label; 203 struct usb_gadget_strings **strings; 204 const struct usb_descriptor_header **descriptors; 205 206 /* REVISIT: bind() functions can be marked __init, which 207 * makes trouble for section mismatch analysis. See if 208 * we can't restructure things to avoid mismatching... 209 */ 210 211 /* configuration management: bind/unbind */ 212 int (*bind)(struct usb_configuration *); 213 void (*unbind)(struct usb_configuration *); 214 int (*setup)(struct usb_configuration *, 215 const struct usb_ctrlrequest *); 216 217 /* fields in the config descriptor */ 218 u8 bConfigurationValue; 219 u8 iConfiguration; 220 u8 bmAttributes; 221 u8 bMaxPower; 222 223 struct usb_composite_dev *cdev; 224 225 /* private: */ 226 /* internals */ 227 struct list_head list; 228 struct list_head functions; 229 u8 next_interface_id; 230 unsigned highspeed:1; 231 unsigned fullspeed:1; 232 struct usb_function *interface[MAX_CONFIG_INTERFACES]; 233 }; 234 235 int usb_add_config(struct usb_composite_dev *, 236 struct usb_configuration *); 237 238 /** 239 * struct usb_composite_driver - groups configurations into a gadget 240 * @name: For diagnostics, identifies the driver. 241 * @dev: Template descriptor for the device, including default device 242 * identifiers. 243 * @strings: tables of strings, keyed by identifiers assigned during bind() 244 * and language IDs provided in control requests 245 * @bind: (REQUIRED) Used to allocate resources that are shared across the 246 * whole device, such as string IDs, and add its configurations using 247 * @usb_add_config(). This may fail by returning a negative errno 248 * value; it should return zero on successful initialization. 249 * @unbind: Reverses @bind(); called as a side effect of unregistering 250 * this driver. 251 * @disconnect: optional driver disconnect method 252 * @suspend: Notifies when the host stops sending USB traffic, 253 * after function notifications 254 * @resume: Notifies configuration when the host restarts USB traffic, 255 * before function notifications 256 * 257 * Devices default to reporting self powered operation. Devices which rely 258 * on bus powered operation should report this in their @bind() method. 259 * 260 * Before returning from @bind, various fields in the template descriptor 261 * may be overridden. These include the idVendor/idProduct/bcdDevice values 262 * normally to bind the appropriate host side driver, and the three strings 263 * (iManufacturer, iProduct, iSerialNumber) normally used to provide user 264 * meaningful device identifiers. (The strings will not be defined unless 265 * they are defined in @dev and @strings.) The correct ep0 maxpacket size 266 * is also reported, as defined by the underlying controller driver. 267 */ 268 struct usb_composite_driver { 269 const char *name; 270 const struct usb_device_descriptor *dev; 271 struct usb_gadget_strings **strings; 272 273 /* REVISIT: bind() functions can be marked __init, which 274 * makes trouble for section mismatch analysis. See if 275 * we can't restructure things to avoid mismatching... 276 */ 277 278 int (*bind)(struct usb_composite_dev *); 279 int (*unbind)(struct usb_composite_dev *); 280 281 void (*disconnect)(struct usb_composite_dev *); 282 283 /* global suspend hooks */ 284 void (*suspend)(struct usb_composite_dev *); 285 void (*resume)(struct usb_composite_dev *); 286 }; 287 288 extern int usb_composite_register(struct usb_composite_driver *); 289 extern void usb_composite_unregister(struct usb_composite_driver *); 290 291 292 /** 293 * struct usb_composite_device - represents one composite usb gadget 294 * @gadget: read-only, abstracts the gadget's usb peripheral controller 295 * @req: used for control responses; buffer is pre-allocated 296 * @bufsiz: size of buffer pre-allocated in @req 297 * @config: the currently active configuration 298 * 299 * One of these devices is allocated and initialized before the 300 * associated device driver's bind() is called. 301 * 302 * OPEN ISSUE: it appears that some WUSB devices will need to be 303 * built by combining a normal (wired) gadget with a wireless one. 304 * This revision of the gadget framework should probably try to make 305 * sure doing that won't hurt too much. 306 * 307 * One notion for how to handle Wireless USB devices involves: 308 * (a) a second gadget here, discovery mechanism TBD, but likely 309 * needing separate "register/unregister WUSB gadget" calls; 310 * (b) updates to usb_gadget to include flags "is it wireless", 311 * "is it wired", plus (presumably in a wrapper structure) 312 * bandgroup and PHY info; 313 * (c) presumably a wireless_ep wrapping a usb_ep, and reporting 314 * wireless-specific parameters like maxburst and maxsequence; 315 * (d) configurations that are specific to wireless links; 316 * (e) function drivers that understand wireless configs and will 317 * support wireless for (additional) function instances; 318 * (f) a function to support association setup (like CBAF), not 319 * necessarily requiring a wireless adapter; 320 * (g) composite device setup that can create one or more wireless 321 * configs, including appropriate association setup support; 322 * (h) more, TBD. 323 */ 324 struct usb_composite_dev { 325 struct usb_gadget *gadget; 326 struct usb_request *req; 327 unsigned bufsiz; 328 329 struct usb_configuration *config; 330 331 /* private: */ 332 /* internals */ 333 unsigned int suspended:1; 334 struct usb_device_descriptor desc; 335 struct list_head configs; 336 struct usb_composite_driver *driver; 337 u8 next_string_id; 338 339 /* the gadget driver won't enable the data pullup 340 * while the deactivation count is nonzero. 341 */ 342 unsigned deactivations; 343 }; 344 345 extern int usb_string_id(struct usb_composite_dev *c); 346 extern int usb_string_ids_tab(struct usb_composite_dev *c, 347 struct usb_string *str); 348 extern int usb_string_ids_n(struct usb_composite_dev *c, unsigned n); 349 350 #endif /* __LINUX_USB_COMPOSITE_H */ 351