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