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 <linux/bitmap.h> 29 30 /* 31 * USB function drivers should return USB_GADGET_DELAYED_STATUS if they 32 * wish to delay the data/status stages of the control transfer till they 33 * are ready. The control transfer will then be kept from completing till 34 * all the function drivers that requested for USB_GADGET_DELAYED_STAUS 35 * invoke usb_composite_setup_continue(). 36 */ 37 #define USB_GADGET_DELAYED_STATUS 0x7fff /* Impossibly large value */ 38 39 struct usb_configuration; 40 41 /** 42 * struct usb_function - describes one function of a configuration 43 * @name: For diagnostics, identifies the function. 44 * @strings: tables of strings, keyed by identifiers assigned during bind() 45 * and by language IDs provided in control requests 46 * @descriptors: Table of full (or low) speed descriptors, using interface and 47 * string identifiers assigned during @bind(). If this pointer is null, 48 * the function will not be available at full speed (or at low speed). 49 * @hs_descriptors: Table of high speed descriptors, using interface and 50 * string identifiers assigned during @bind(). If this pointer is null, 51 * the function will not be available at high speed. 52 * @ss_descriptors: Table of super speed descriptors, using interface and 53 * string identifiers assigned during @bind(). If this pointer is null, 54 * the function will not be available at super 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 struct usb_descriptor_header **ss_descriptors; 103 104 struct usb_configuration *config; 105 106 /* REVISIT: bind() functions can be marked __init, which 107 * makes trouble for section mismatch analysis. See if 108 * we can't restructure things to avoid mismatching. 109 * Related: unbind() may kfree() but bind() won't... 110 */ 111 112 /* configuration management: bind/unbind */ 113 int (*bind)(struct usb_configuration *, 114 struct usb_function *); 115 void (*unbind)(struct usb_configuration *, 116 struct usb_function *); 117 118 /* runtime state management */ 119 int (*set_alt)(struct usb_function *, 120 unsigned interface, unsigned alt); 121 int (*get_alt)(struct usb_function *, 122 unsigned interface); 123 void (*disable)(struct usb_function *); 124 int (*setup)(struct usb_function *, 125 const struct usb_ctrlrequest *); 126 void (*suspend)(struct usb_function *); 127 void (*resume)(struct usb_function *); 128 129 /* private: */ 130 /* internals */ 131 struct list_head list; 132 DECLARE_BITMAP(endpoints, 32); 133 }; 134 135 int usb_add_function(struct usb_configuration *, struct usb_function *); 136 137 int usb_function_deactivate(struct usb_function *); 138 int usb_function_activate(struct usb_function *); 139 140 int usb_interface_id(struct usb_configuration *, struct usb_function *); 141 142 /** 143 * ep_choose - select descriptor endpoint at current device speed 144 * @g: gadget, connected and running at some speed 145 * @hs: descriptor to use for high speed operation 146 * @fs: descriptor to use for full or low speed operation 147 */ 148 static inline struct usb_endpoint_descriptor * 149 ep_choose(struct usb_gadget *g, struct usb_endpoint_descriptor *hs, 150 struct usb_endpoint_descriptor *fs) 151 { 152 if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH) 153 return hs; 154 return fs; 155 } 156 157 #define MAX_CONFIG_INTERFACES 16 /* arbitrary; max 255 */ 158 159 /** 160 * struct usb_configuration - represents one gadget configuration 161 * @label: For diagnostics, describes the configuration. 162 * @strings: Tables of strings, keyed by identifiers assigned during @bind() 163 * and by language IDs provided in control requests. 164 * @descriptors: Table of descriptors preceding all function descriptors. 165 * Examples include OTG and vendor-specific descriptors. 166 * @bind: Called from @usb_add_config() to allocate resources unique to this 167 * configuration and to call @usb_add_function() for each function used. 168 * @unbind: Reverses @bind; called as a side effect of unregistering the 169 * driver which added this configuration. 170 * @setup: Used to delegate control requests that aren't handled by standard 171 * device infrastructure or directed at a specific interface. 172 * @bConfigurationValue: Copied into configuration descriptor. 173 * @iConfiguration: Copied into configuration descriptor. 174 * @bmAttributes: Copied into configuration descriptor. 175 * @bMaxPower: Copied into configuration descriptor. 176 * @cdev: assigned by @usb_add_config() before calling @bind(); this is 177 * the device associated with this configuration. 178 * 179 * Configurations are building blocks for gadget drivers structured around 180 * function drivers. Simple USB gadgets require only one function and one 181 * configuration, and handle dual-speed hardware by always providing the same 182 * functionality. Slightly more complex gadgets may have more than one 183 * single-function configuration at a given speed; or have configurations 184 * that only work at one speed. 185 * 186 * Composite devices are, by definition, ones with configurations which 187 * include more than one function. 188 * 189 * The lifecycle of a usb_configuration includes allocation, initialization 190 * of the fields described above, and calling @usb_add_config() to set up 191 * internal data and bind it to a specific device. The configuration's 192 * @bind() method is then used to initialize all the functions and then 193 * call @usb_add_function() for them. 194 * 195 * Those functions would normally be independant of each other, but that's 196 * not mandatory. CDC WMC devices are an example where functions often 197 * depend on other functions, with some functions subsidiary to others. 198 * Such interdependency may be managed in any way, so long as all of the 199 * descriptors complete by the time the composite driver returns from 200 * its bind() routine. 201 */ 202 struct usb_configuration { 203 const char *label; 204 struct usb_gadget_strings **strings; 205 const struct usb_descriptor_header **descriptors; 206 207 /* REVISIT: bind() functions can be marked __init, which 208 * makes trouble for section mismatch analysis. See if 209 * we can't restructure things to avoid mismatching... 210 */ 211 212 /* configuration management: bind/unbind */ 213 int (*bind)(struct usb_configuration *); 214 void (*unbind)(struct usb_configuration *); 215 int (*setup)(struct usb_configuration *, 216 const struct usb_ctrlrequest *); 217 218 /* fields in the config descriptor */ 219 u8 bConfigurationValue; 220 u8 iConfiguration; 221 u8 bmAttributes; 222 u8 bMaxPower; 223 224 struct usb_composite_dev *cdev; 225 226 /* private: */ 227 /* internals */ 228 struct list_head list; 229 struct list_head functions; 230 u8 next_interface_id; 231 unsigned superspeed:1; 232 unsigned highspeed:1; 233 unsigned fullspeed:1; 234 struct usb_function *interface[MAX_CONFIG_INTERFACES]; 235 }; 236 237 int usb_add_config(struct usb_composite_dev *, 238 struct usb_configuration *); 239 240 /** 241 * struct usb_composite_driver - groups configurations into a gadget 242 * @name: For diagnostics, identifies the driver. 243 * @dev: Template descriptor for the device, including default device 244 * identifiers. 245 * @strings: tables of strings, keyed by identifiers assigned during bind() 246 * and language IDs provided in control requests 247 * @bind: (REQUIRED) Used to allocate resources that are shared across the 248 * whole device, such as string IDs, and add its configurations using 249 * @usb_add_config(). This may fail by returning a negative errno 250 * value; it should return zero on successful initialization. 251 * @unbind: Reverses @bind(); called as a side effect of unregistering 252 * this driver. 253 * @disconnect: optional driver disconnect method 254 * @suspend: Notifies when the host stops sending USB traffic, 255 * after function notifications 256 * @resume: Notifies configuration when the host restarts USB traffic, 257 * before function notifications 258 * 259 * Devices default to reporting self powered operation. Devices which rely 260 * on bus powered operation should report this in their @bind() method. 261 * 262 * Before returning from @bind, various fields in the template descriptor 263 * may be overridden. These include the idVendor/idProduct/bcdDevice values 264 * normally to bind the appropriate host side driver, and the three strings 265 * (iManufacturer, iProduct, iSerialNumber) normally used to provide user 266 * meaningful device identifiers. (The strings will not be defined unless 267 * they are defined in @dev and @strings.) The correct ep0 maxpacket size 268 * is also reported, as defined by the underlying controller driver. 269 */ 270 struct usb_composite_driver { 271 const char *name; 272 const struct usb_device_descriptor *dev; 273 struct usb_gadget_strings **strings; 274 275 /* REVISIT: bind() functions can be marked __init, which 276 * makes trouble for section mismatch analysis. See if 277 * we can't restructure things to avoid mismatching... 278 */ 279 280 int (*bind)(struct usb_composite_dev *); 281 int (*unbind)(struct usb_composite_dev *); 282 283 void (*disconnect)(struct usb_composite_dev *); 284 285 /* global suspend hooks */ 286 void (*suspend)(struct usb_composite_dev *); 287 void (*resume)(struct usb_composite_dev *); 288 }; 289 290 extern int usb_composite_register(struct usb_composite_driver *); 291 extern void usb_composite_unregister(struct usb_composite_driver *); 292 293 294 /** 295 * struct usb_composite_device - represents one composite usb gadget 296 * @gadget: read-only, abstracts the gadget's usb peripheral controller 297 * @req: used for control responses; buffer is pre-allocated 298 * @bufsiz: size of buffer pre-allocated in @req 299 * @config: the currently active configuration 300 * 301 * One of these devices is allocated and initialized before the 302 * associated device driver's bind() is called. 303 * 304 * OPEN ISSUE: it appears that some WUSB devices will need to be 305 * built by combining a normal (wired) gadget with a wireless one. 306 * This revision of the gadget framework should probably try to make 307 * sure doing that won't hurt too much. 308 * 309 * One notion for how to handle Wireless USB devices involves: 310 * (a) a second gadget here, discovery mechanism TBD, but likely 311 * needing separate "register/unregister WUSB gadget" calls; 312 * (b) updates to usb_gadget to include flags "is it wireless", 313 * "is it wired", plus (presumably in a wrapper structure) 314 * bandgroup and PHY info; 315 * (c) presumably a wireless_ep wrapping a usb_ep, and reporting 316 * wireless-specific parameters like maxburst and maxsequence; 317 * (d) configurations that are specific to wireless links; 318 * (e) function drivers that understand wireless configs and will 319 * support wireless for (additional) function instances; 320 * (f) a function to support association setup (like CBAF), not 321 * necessarily requiring a wireless adapter; 322 * (g) composite device setup that can create one or more wireless 323 * configs, including appropriate association setup support; 324 * (h) more, TBD. 325 */ 326 struct usb_composite_dev { 327 struct usb_gadget *gadget; 328 struct usb_request *req; 329 unsigned bufsiz; 330 331 struct usb_configuration *config; 332 333 /* private: */ 334 /* internals */ 335 unsigned int suspended:1; 336 struct usb_device_descriptor __aligned(CONFIG_SYS_CACHELINE_SIZE) desc; 337 struct list_head configs; 338 struct usb_composite_driver *driver; 339 u8 next_string_id; 340 341 /* the gadget driver won't enable the data pullup 342 * while the deactivation count is nonzero. 343 */ 344 unsigned deactivations; 345 }; 346 347 extern int usb_string_id(struct usb_composite_dev *c); 348 extern int usb_string_ids_tab(struct usb_composite_dev *c, 349 struct usb_string *str); 350 extern int usb_string_ids_n(struct usb_composite_dev *c, unsigned n); 351 352 #endif /* __LINUX_USB_COMPOSITE_H */ 353