1 /* 2 * composite.h -- framework for usb gadgets which are composite devices 3 * 4 * Copyright (C) 2006-2008 David Brownell 5 * 6 * SPDX-License-Identifier: GPL-2.0+ 7 */ 8 9 #ifndef __LINUX_USB_COMPOSITE_H 10 #define __LINUX_USB_COMPOSITE_H 11 12 /* 13 * This framework is an optional layer on top of the USB Gadget interface, 14 * making it easier to build (a) Composite devices, supporting multiple 15 * functions within any single configuration, and (b) Multi-configuration 16 * devices, also supporting multiple functions but without necessarily 17 * having more than one function per configuration. 18 * 19 * Example: a device with a single configuration supporting both network 20 * link and mass storage functions is a composite device. Those functions 21 * might alternatively be packaged in individual configurations, but in 22 * the composite model the host can use both functions at the same time. 23 */ 24 25 #include <common.h> 26 #include <linux/usb/ch9.h> 27 #include <linux/usb/gadget.h> 28 #include <usb/lin_gadget_compat.h> 29 30 struct usb_configuration; 31 32 /** 33 * struct usb_function - describes one function of a configuration 34 * @name: For diagnostics, identifies the function. 35 * @strings: tables of strings, keyed by identifiers assigned during bind() 36 * and by language IDs provided in control requests 37 * @descriptors: Table of full (or low) speed descriptors, using interface and 38 * string identifiers assigned during @bind(). If this pointer is null, 39 * the function will not be available at full speed (or at low speed). 40 * @hs_descriptors: Table of high speed descriptors, using interface and 41 * string identifiers assigned during @bind(). If this pointer is null, 42 * the function will not be available at high speed. 43 * @config: assigned when @usb_add_function() is called; this is the 44 * configuration with which this function is associated. 45 * @bind: Before the gadget can register, all of its functions bind() to the 46 * available resources including string and interface identifiers used 47 * in interface or class descriptors; endpoints; I/O buffers; and so on. 48 * @unbind: Reverses @bind; called as a side effect of unregistering the 49 * driver which added this function. 50 * @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may 51 * initialize usb_ep.driver data at this time (when it is used). 52 * Note that setting an interface to its current altsetting resets 53 * interface state, and that all interfaces have a disabled state. 54 * @get_alt: Returns the active altsetting. If this is not provided, 55 * then only altsetting zero is supported. 56 * @disable: (REQUIRED) Indicates the function should be disabled. Reasons 57 * include host resetting or reconfiguring the gadget, and disconnection. 58 * @setup: Used for interface-specific control requests. 59 * @suspend: Notifies functions when the host stops sending USB traffic. 60 * @resume: Notifies functions when the host restarts USB traffic. 61 * 62 * A single USB function uses one or more interfaces, and should in most 63 * cases support operation at both full and high speeds. Each function is 64 * associated by @usb_add_function() with a one configuration; that function 65 * causes @bind() to be called so resources can be allocated as part of 66 * setting up a gadget driver. Those resources include endpoints, which 67 * should be allocated using @usb_ep_autoconfig(). 68 * 69 * To support dual speed operation, a function driver provides descriptors 70 * for both high and full speed operation. Except in rare cases that don't 71 * involve bulk endpoints, each speed needs different endpoint descriptors. 72 * 73 * Function drivers choose their own strategies for managing instance data. 74 * The simplest strategy just declares it "static', which means the function 75 * can only be activated once. If the function needs to be exposed in more 76 * than one configuration at a given speed, it needs to support multiple 77 * usb_function structures (one for each configuration). 78 * 79 * A more complex strategy might encapsulate a @usb_function structure inside 80 * a driver-specific instance structure to allows multiple activations. An 81 * example of multiple activations might be a CDC ACM function that supports 82 * two or more distinct instances within the same configuration, providing 83 * several independent logical data links to a USB host. 84 */ 85 struct usb_function { 86 const char *name; 87 struct usb_gadget_strings **strings; 88 struct usb_descriptor_header **descriptors; 89 struct usb_descriptor_header **hs_descriptors; 90 91 struct usb_configuration *config; 92 93 /* REVISIT: bind() functions can be marked __init, which 94 * makes trouble for section mismatch analysis. See if 95 * we can't restructure things to avoid mismatching. 96 * Related: unbind() may kfree() but bind() won't... 97 */ 98 99 /* configuration management: bind/unbind */ 100 int (*bind)(struct usb_configuration *, 101 struct usb_function *); 102 void (*unbind)(struct usb_configuration *, 103 struct usb_function *); 104 105 /* runtime state management */ 106 int (*set_alt)(struct usb_function *, 107 unsigned interface, unsigned alt); 108 int (*get_alt)(struct usb_function *, 109 unsigned interface); 110 void (*disable)(struct usb_function *); 111 int (*setup)(struct usb_function *, 112 const struct usb_ctrlrequest *); 113 void (*suspend)(struct usb_function *); 114 void (*resume)(struct usb_function *); 115 116 /* private: */ 117 /* internals */ 118 struct list_head list; 119 DECLARE_BITMAP(endpoints, 32); 120 }; 121 122 int usb_add_function(struct usb_configuration *, struct usb_function *); 123 124 int usb_function_deactivate(struct usb_function *); 125 int usb_function_activate(struct usb_function *); 126 127 int usb_interface_id(struct usb_configuration *, struct usb_function *); 128 129 /** 130 * ep_choose - select descriptor endpoint at current device speed 131 * @g: gadget, connected and running at some speed 132 * @hs: descriptor to use for high speed operation 133 * @fs: descriptor to use for full or low speed operation 134 */ 135 static inline struct usb_endpoint_descriptor * 136 ep_choose(struct usb_gadget *g, struct usb_endpoint_descriptor *hs, 137 struct usb_endpoint_descriptor *fs) 138 { 139 if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH) 140 return hs; 141 return fs; 142 } 143 144 #define MAX_CONFIG_INTERFACES 16 /* arbitrary; max 255 */ 145 146 /** 147 * struct usb_configuration - represents one gadget configuration 148 * @label: For diagnostics, describes the configuration. 149 * @strings: Tables of strings, keyed by identifiers assigned during @bind() 150 * and by language IDs provided in control requests. 151 * @descriptors: Table of descriptors preceding all function descriptors. 152 * Examples include OTG and vendor-specific descriptors. 153 * @bind: Called from @usb_add_config() to allocate resources unique to this 154 * configuration and to call @usb_add_function() for each function used. 155 * @unbind: Reverses @bind; called as a side effect of unregistering the 156 * driver which added this configuration. 157 * @setup: Used to delegate control requests that aren't handled by standard 158 * device infrastructure or directed at a specific interface. 159 * @bConfigurationValue: Copied into configuration descriptor. 160 * @iConfiguration: Copied into configuration descriptor. 161 * @bmAttributes: Copied into configuration descriptor. 162 * @bMaxPower: Copied into configuration descriptor. 163 * @cdev: assigned by @usb_add_config() before calling @bind(); this is 164 * the device associated with this configuration. 165 * 166 * Configurations are building blocks for gadget drivers structured around 167 * function drivers. Simple USB gadgets require only one function and one 168 * configuration, and handle dual-speed hardware by always providing the same 169 * functionality. Slightly more complex gadgets may have more than one 170 * single-function configuration at a given speed; or have configurations 171 * that only work at one speed. 172 * 173 * Composite devices are, by definition, ones with configurations which 174 * include more than one function. 175 * 176 * The lifecycle of a usb_configuration includes allocation, initialization 177 * of the fields described above, and calling @usb_add_config() to set up 178 * internal data and bind it to a specific device. The configuration's 179 * @bind() method is then used to initialize all the functions and then 180 * call @usb_add_function() for them. 181 * 182 * Those functions would normally be independant of each other, but that's 183 * not mandatory. CDC WMC devices are an example where functions often 184 * depend on other functions, with some functions subsidiary to others. 185 * Such interdependency may be managed in any way, so long as all of the 186 * descriptors complete by the time the composite driver returns from 187 * its bind() routine. 188 */ 189 struct usb_configuration { 190 const char *label; 191 struct usb_gadget_strings **strings; 192 const struct usb_descriptor_header **descriptors; 193 194 /* REVISIT: bind() functions can be marked __init, which 195 * makes trouble for section mismatch analysis. See if 196 * we can't restructure things to avoid mismatching... 197 */ 198 199 /* configuration management: bind/unbind */ 200 int (*bind)(struct usb_configuration *); 201 void (*unbind)(struct usb_configuration *); 202 int (*setup)(struct usb_configuration *, 203 const struct usb_ctrlrequest *); 204 205 /* fields in the config descriptor */ 206 u8 bConfigurationValue; 207 u8 iConfiguration; 208 u8 bmAttributes; 209 u8 bMaxPower; 210 211 struct usb_composite_dev *cdev; 212 213 /* private: */ 214 /* internals */ 215 struct list_head list; 216 struct list_head functions; 217 u8 next_interface_id; 218 unsigned highspeed:1; 219 unsigned fullspeed:1; 220 struct usb_function *interface[MAX_CONFIG_INTERFACES]; 221 }; 222 223 int usb_add_config(struct usb_composite_dev *, 224 struct usb_configuration *); 225 226 /** 227 * struct usb_composite_driver - groups configurations into a gadget 228 * @name: For diagnostics, identifies the driver. 229 * @dev: Template descriptor for the device, including default device 230 * identifiers. 231 * @strings: tables of strings, keyed by identifiers assigned during bind() 232 * and language IDs provided in control requests 233 * @bind: (REQUIRED) Used to allocate resources that are shared across the 234 * whole device, such as string IDs, and add its configurations using 235 * @usb_add_config(). This may fail by returning a negative errno 236 * value; it should return zero on successful initialization. 237 * @unbind: Reverses @bind(); called as a side effect of unregistering 238 * this driver. 239 * @disconnect: optional driver disconnect method 240 * @suspend: Notifies when the host stops sending USB traffic, 241 * after function notifications 242 * @resume: Notifies configuration when the host restarts USB traffic, 243 * before function notifications 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 void (*disconnect)(struct usb_composite_dev *); 270 271 /* global suspend hooks */ 272 void (*suspend)(struct usb_composite_dev *); 273 void (*resume)(struct usb_composite_dev *); 274 }; 275 276 extern int usb_composite_register(struct usb_composite_driver *); 277 extern void usb_composite_unregister(struct usb_composite_driver *); 278 279 280 /** 281 * struct usb_composite_device - represents one composite usb gadget 282 * @gadget: read-only, abstracts the gadget's usb peripheral controller 283 * @req: used for control responses; buffer is pre-allocated 284 * @bufsiz: size of buffer pre-allocated in @req 285 * @config: the currently active configuration 286 * 287 * One of these devices is allocated and initialized before the 288 * associated device driver's bind() is called. 289 * 290 * OPEN ISSUE: it appears that some WUSB devices will need to be 291 * built by combining a normal (wired) gadget with a wireless one. 292 * This revision of the gadget framework should probably try to make 293 * sure doing that won't hurt too much. 294 * 295 * One notion for how to handle Wireless USB devices involves: 296 * (a) a second gadget here, discovery mechanism TBD, but likely 297 * needing separate "register/unregister WUSB gadget" calls; 298 * (b) updates to usb_gadget to include flags "is it wireless", 299 * "is it wired", plus (presumably in a wrapper structure) 300 * bandgroup and PHY info; 301 * (c) presumably a wireless_ep wrapping a usb_ep, and reporting 302 * wireless-specific parameters like maxburst and maxsequence; 303 * (d) configurations that are specific to wireless links; 304 * (e) function drivers that understand wireless configs and will 305 * support wireless for (additional) function instances; 306 * (f) a function to support association setup (like CBAF), not 307 * necessarily requiring a wireless adapter; 308 * (g) composite device setup that can create one or more wireless 309 * configs, including appropriate association setup support; 310 * (h) more, TBD. 311 */ 312 struct usb_composite_dev { 313 struct usb_gadget *gadget; 314 struct usb_request *req; 315 unsigned bufsiz; 316 317 struct usb_configuration *config; 318 319 /* private: */ 320 /* internals */ 321 unsigned int suspended:1; 322 struct usb_device_descriptor __aligned(CONFIG_SYS_CACHELINE_SIZE) desc; 323 struct list_head configs; 324 struct usb_composite_driver *driver; 325 u8 next_string_id; 326 327 /* the gadget driver won't enable the data pullup 328 * while the deactivation count is nonzero. 329 */ 330 unsigned deactivations; 331 }; 332 333 extern int usb_string_id(struct usb_composite_dev *c); 334 extern int usb_string_ids_tab(struct usb_composite_dev *c, 335 struct usb_string *str); 336 extern int usb_string_ids_n(struct usb_composite_dev *c, unsigned n); 337 338 #endif /* __LINUX_USB_COMPOSITE_H */ 339