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 /* internals */ 128 struct list_head list; 129 }; 130 131 int usb_add_function(struct usb_configuration *, struct usb_function *); 132 133 int usb_interface_id(struct usb_configuration *, struct usb_function *); 134 135 /** 136 * ep_choose - select descriptor endpoint at current device speed 137 * @g: gadget, connected and running at some speed 138 * @hs: descriptor to use for high speed operation 139 * @fs: descriptor to use for full or low speed operation 140 */ 141 static inline struct usb_endpoint_descriptor * 142 ep_choose(struct usb_gadget *g, struct usb_endpoint_descriptor *hs, 143 struct usb_endpoint_descriptor *fs) 144 { 145 if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH) 146 return hs; 147 return fs; 148 } 149 150 #define MAX_CONFIG_INTERFACES 16 /* arbitrary; max 255 */ 151 152 /** 153 * struct usb_configuration - represents one gadget configuration 154 * @label: For diagnostics, describes the configuration. 155 * @strings: Tables of strings, keyed by identifiers assigned during @bind() 156 * and by language IDs provided in control requests. 157 * @descriptors: Table of descriptors preceding all function descriptors. 158 * Examples include OTG and vendor-specific descriptors. 159 * @bind: Called from @usb_add_config() to allocate resources unique to this 160 * configuration and to call @usb_add_function() for each function used. 161 * @unbind: Reverses @bind; called as a side effect of unregistering the 162 * driver which added this configuration. 163 * @setup: Used to delegate control requests that aren't handled by standard 164 * device infrastructure or directed at a specific interface. 165 * @bConfigurationValue: Copied into configuration descriptor. 166 * @iConfiguration: Copied into configuration descriptor. 167 * @bmAttributes: Copied into configuration descriptor. 168 * @bMaxPower: Copied into configuration descriptor. 169 * @cdev: assigned by @usb_add_config() before calling @bind(); this is 170 * the device associated with this configuration. 171 * 172 * Configurations are building blocks for gadget drivers structured around 173 * function drivers. Simple USB gadgets require only one function and one 174 * configuration, and handle dual-speed hardware by always providing the same 175 * functionality. Slightly more complex gadgets may have more than one 176 * single-function configuration at a given speed; or have configurations 177 * that only work at one speed. 178 * 179 * Composite devices are, by definition, ones with configurations which 180 * include more than one function. 181 * 182 * The lifecycle of a usb_configuration includes allocation, initialization 183 * of the fields described above, and calling @usb_add_config() to set up 184 * internal data and bind it to a specific device. The configuration's 185 * @bind() method is then used to initialize all the functions and then 186 * call @usb_add_function() for them. 187 * 188 * Those functions would normally be independant of each other, but that's 189 * not mandatory. CDC WMC devices are an example where functions often 190 * depend on other functions, with some functions subsidiary to others. 191 * Such interdependency may be managed in any way, so long as all of the 192 * descriptors complete by the time the composite driver returns from 193 * its bind() routine. 194 */ 195 struct usb_configuration { 196 const char *label; 197 struct usb_gadget_strings **strings; 198 const struct usb_descriptor_header **descriptors; 199 200 /* REVISIT: bind() functions can be marked __init, which 201 * makes trouble for section mismatch analysis. See if 202 * we can't restructure things to avoid mismatching... 203 */ 204 205 /* configuration management: bind/unbind */ 206 int (*bind)(struct usb_configuration *); 207 void (*unbind)(struct usb_configuration *); 208 int (*setup)(struct usb_configuration *, 209 const struct usb_ctrlrequest *); 210 211 /* fields in the config descriptor */ 212 u8 bConfigurationValue; 213 u8 iConfiguration; 214 u8 bmAttributes; 215 u8 bMaxPower; 216 217 struct usb_composite_dev *cdev; 218 219 /* internals */ 220 struct list_head list; 221 struct list_head functions; 222 u8 next_interface_id; 223 unsigned highspeed:1; 224 unsigned fullspeed:1; 225 struct usb_function *interface[MAX_CONFIG_INTERFACES]; 226 }; 227 228 int usb_add_config(struct usb_composite_dev *, 229 struct usb_configuration *); 230 231 /** 232 * struct usb_composite_driver - groups configurations into a gadget 233 * @name: For diagnostics, identifies the driver. 234 * @dev: Template descriptor for the device, including default device 235 * identifiers. 236 * @strings: tables of strings, keyed by identifiers assigned during bind() 237 * and language IDs provided in control requests 238 * @bind: (REQUIRED) Used to allocate resources that are shared across the 239 * whole device, such as string IDs, and add its configurations using 240 * @usb_add_config(). This may fail by returning a negative errno 241 * value; it should return zero on successful initialization. 242 * @unbind: Reverses @bind(); called as a side effect of unregistering 243 * this driver. 244 * 245 * Devices default to reporting self powered operation. Devices which rely 246 * on bus powered operation should report this in their @bind() method. 247 * 248 * Before returning from @bind, various fields in the template descriptor 249 * may be overridden. These include the idVendor/idProduct/bcdDevice values 250 * normally to bind the appropriate host side driver, and the three strings 251 * (iManufacturer, iProduct, iSerialNumber) normally used to provide user 252 * meaningful device identifiers. (The strings will not be defined unless 253 * they are defined in @dev and @strings.) The correct ep0 maxpacket size 254 * is also reported, as defined by the underlying controller driver. 255 */ 256 struct usb_composite_driver { 257 const char *name; 258 const struct usb_device_descriptor *dev; 259 struct usb_gadget_strings **strings; 260 261 /* REVISIT: bind() functions can be marked __init, which 262 * makes trouble for section mismatch analysis. See if 263 * we can't restructure things to avoid mismatching... 264 */ 265 266 int (*bind)(struct usb_composite_dev *); 267 int (*unbind)(struct usb_composite_dev *); 268 }; 269 270 extern int usb_composite_register(struct usb_composite_driver *); 271 extern void usb_composite_unregister(struct usb_composite_driver *); 272 273 274 /** 275 * struct usb_composite_device - represents one composite usb gadget 276 * @gadget: read-only, abstracts the gadget's usb peripheral controller 277 * @req: used for control responses; buffer is pre-allocated 278 * @bufsiz: size of buffer pre-allocated in @req 279 * @config: the currently active configuration 280 * 281 * One of these devices is allocated and initialized before the 282 * associated device driver's bind() is called. 283 * 284 * OPEN ISSUE: it appears that some WUSB devices will need to be 285 * built by combining a normal (wired) gadget with a wireless one. 286 * This revision of the gadget framework should probably try to make 287 * sure doing that won't hurt too much. 288 * 289 * One notion for how to handle Wireless USB devices involves: 290 * (a) a second gadget here, discovery mechanism TBD, but likely 291 * needing separate "register/unregister WUSB gadget" calls; 292 * (b) updates to usb_gadget to include flags "is it wireless", 293 * "is it wired", plus (presumably in a wrapper structure) 294 * bandgroup and PHY info; 295 * (c) presumably a wireless_ep wrapping a usb_ep, and reporting 296 * wireless-specific parameters like maxburst and maxsequence; 297 * (d) configurations that are specific to wireless links; 298 * (e) function drivers that understand wireless configs and will 299 * support wireless for (additional) function instances; 300 * (f) a function to support association setup (like CBAF), not 301 * necessarily requiring a wireless adapter; 302 * (g) composite device setup that can create one or more wireless 303 * configs, including appropriate association setup support; 304 * (h) more, TBD. 305 */ 306 struct usb_composite_dev { 307 struct usb_gadget *gadget; 308 struct usb_request *req; 309 unsigned bufsiz; 310 311 struct usb_configuration *config; 312 313 /* internals */ 314 struct usb_device_descriptor desc; 315 struct list_head configs; 316 struct usb_composite_driver *driver; 317 u8 next_string_id; 318 319 spinlock_t lock; 320 321 /* REVISIT use and existence of lock ... */ 322 }; 323 324 extern int usb_string_id(struct usb_composite_dev *c); 325 326 /* messaging utils */ 327 #define DBG(d, fmt, args...) \ 328 dev_dbg(&(d)->gadget->dev , fmt , ## args) 329 #define VDBG(d, fmt, args...) \ 330 dev_vdbg(&(d)->gadget->dev , fmt , ## args) 331 #define ERROR(d, fmt, args...) \ 332 dev_err(&(d)->gadget->dev , fmt , ## args) 333 #define WARNING(d, fmt, args...) \ 334 dev_warn(&(d)->gadget->dev , fmt , ## args) 335 #define INFO(d, fmt, args...) \ 336 dev_info(&(d)->gadget->dev , fmt , ## args) 337 338 #endif /* __LINUX_USB_COMPOSITE_H */ 339