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