1 /* SPDX-License-Identifier: GPL-2.0+ */ 2 /* 3 * composite.h -- framework for usb gadgets which are composite devices 4 * 5 * Copyright (C) 2006-2008 David Brownell 6 */ 7 8 #ifndef __LINUX_USB_COMPOSITE_H 9 #define __LINUX_USB_COMPOSITE_H 10 11 /* 12 * This framework is an optional layer on top of the USB Gadget interface, 13 * making it easier to build (a) Composite devices, supporting multiple 14 * functions within any single configuration, and (b) Multi-configuration 15 * devices, also supporting multiple functions but without necessarily 16 * having more than one function per configuration. 17 * 18 * Example: a device with a single configuration supporting both network 19 * link and mass storage functions is a composite device. Those functions 20 * might alternatively be packaged in individual configurations, but in 21 * the composite model the host can use both functions at the same time. 22 */ 23 24 #include <common.h> 25 #include <linux/usb/ch9.h> 26 #include <linux/usb/gadget.h> 27 #include <usb/lin_gadget_compat.h> 28 29 /* 30 * USB function drivers should return USB_GADGET_DELAYED_STATUS if they 31 * wish to delay the data/status stages of the control transfer till they 32 * are ready. The control transfer will then be kept from completing till 33 * all the function drivers that requested for USB_GADGET_DELAYED_STAUS 34 * invoke usb_composite_setup_continue(). 35 */ 36 #define USB_GADGET_DELAYED_STATUS 0x7fff /* Impossibly large value */ 37 38 struct usb_configuration; 39 40 /** 41 * struct usb_function - describes one function of a configuration 42 * @name: For diagnostics, identifies the function. 43 * @strings: tables of strings, keyed by identifiers assigned during bind() 44 * and by language IDs provided in control requests 45 * @descriptors: Table of full (or low) speed descriptors, using interface and 46 * string identifiers assigned during @bind(). If this pointer is null, 47 * the function will not be available at full speed (or at low speed). 48 * @hs_descriptors: Table of high speed descriptors, using interface and 49 * string identifiers assigned during @bind(). If this pointer is null, 50 * the function will not be available at high speed. 51 * @config: assigned when @usb_add_function() is called; this is the 52 * configuration with which this function is associated. 53 * @bind: Before the gadget can register, all of its functions bind() to the 54 * available resources including string and interface identifiers used 55 * in interface or class descriptors; endpoints; I/O buffers; and so on. 56 * @unbind: Reverses @bind; called as a side effect of unregistering the 57 * driver which added this function. 58 * @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may 59 * initialize usb_ep.driver data at this time (when it is used). 60 * Note that setting an interface to its current altsetting resets 61 * interface state, and that all interfaces have a disabled state. 62 * @get_alt: Returns the active altsetting. If this is not provided, 63 * then only altsetting zero is supported. 64 * @disable: (REQUIRED) Indicates the function should be disabled. Reasons 65 * include host resetting or reconfiguring the gadget, and disconnection. 66 * @setup: Used for interface-specific control requests. 67 * @suspend: Notifies functions when the host stops sending USB traffic. 68 * @resume: Notifies functions when the host restarts USB traffic. 69 * 70 * A single USB function uses one or more interfaces, and should in most 71 * cases support operation at both full and high speeds. Each function is 72 * associated by @usb_add_function() with a one configuration; that function 73 * causes @bind() to be called so resources can be allocated as part of 74 * setting up a gadget driver. Those resources include endpoints, which 75 * should be allocated using @usb_ep_autoconfig(). 76 * 77 * To support dual speed operation, a function driver provides descriptors 78 * for both high and full speed operation. Except in rare cases that don't 79 * involve bulk endpoints, each speed needs different endpoint descriptors. 80 * 81 * Function drivers choose their own strategies for managing instance data. 82 * The simplest strategy just declares it "static', which means the function 83 * can only be activated once. If the function needs to be exposed in more 84 * than one configuration at a given speed, it needs to support multiple 85 * usb_function structures (one for each configuration). 86 * 87 * A more complex strategy might encapsulate a @usb_function structure inside 88 * a driver-specific instance structure to allows multiple activations. An 89 * example of multiple activations might be a CDC ACM function that supports 90 * two or more distinct instances within the same configuration, providing 91 * several independent logical data links to a USB host. 92 */ 93 struct usb_function { 94 const char *name; 95 struct usb_gadget_strings **strings; 96 struct usb_descriptor_header **descriptors; 97 struct usb_descriptor_header **hs_descriptors; 98 99 struct usb_configuration *config; 100 101 /* REVISIT: bind() functions can be marked __init, which 102 * makes trouble for section mismatch analysis. See if 103 * we can't restructure things to avoid mismatching. 104 * Related: unbind() may kfree() but bind() won't... 105 */ 106 107 /* configuration management: bind/unbind */ 108 int (*bind)(struct usb_configuration *, 109 struct usb_function *); 110 void (*unbind)(struct usb_configuration *, 111 struct usb_function *); 112 113 /* runtime state management */ 114 int (*set_alt)(struct usb_function *, 115 unsigned interface, unsigned alt); 116 int (*get_alt)(struct usb_function *, 117 unsigned interface); 118 void (*disable)(struct usb_function *); 119 int (*setup)(struct usb_function *, 120 const struct usb_ctrlrequest *); 121 void (*suspend)(struct usb_function *); 122 void (*resume)(struct usb_function *); 123 124 /* private: */ 125 /* internals */ 126 struct list_head list; 127 DECLARE_BITMAP(endpoints, 32); 128 }; 129 130 int usb_add_function(struct usb_configuration *, struct usb_function *); 131 132 int usb_function_deactivate(struct usb_function *); 133 int usb_function_activate(struct usb_function *); 134 135 int usb_interface_id(struct usb_configuration *, struct usb_function *); 136 137 /** 138 * ep_choose - select descriptor endpoint at current device speed 139 * @g: gadget, connected and running at some speed 140 * @hs: descriptor to use for high speed operation 141 * @fs: descriptor to use for full or low speed operation 142 */ 143 static inline struct usb_endpoint_descriptor * 144 ep_choose(struct usb_gadget *g, struct usb_endpoint_descriptor *hs, 145 struct usb_endpoint_descriptor *fs) 146 { 147 if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH) 148 return hs; 149 return fs; 150 } 151 152 #define MAX_CONFIG_INTERFACES 16 /* arbitrary; max 255 */ 153 154 /** 155 * struct usb_configuration - represents one gadget configuration 156 * @label: For diagnostics, describes the configuration. 157 * @strings: Tables of strings, keyed by identifiers assigned during @bind() 158 * and by language IDs provided in control requests. 159 * @descriptors: Table of descriptors preceding all function descriptors. 160 * Examples include OTG and vendor-specific descriptors. 161 * @bind: Called from @usb_add_config() to allocate resources unique to this 162 * configuration and to call @usb_add_function() for each function used. 163 * @unbind: Reverses @bind; called as a side effect of unregistering the 164 * driver which added this configuration. 165 * @setup: Used to delegate control requests that aren't handled by standard 166 * device infrastructure or directed at a specific interface. 167 * @bConfigurationValue: Copied into configuration descriptor. 168 * @iConfiguration: Copied into configuration descriptor. 169 * @bmAttributes: Copied into configuration descriptor. 170 * @bMaxPower: Copied into configuration descriptor. 171 * @cdev: assigned by @usb_add_config() before calling @bind(); this is 172 * the device associated with this configuration. 173 * 174 * Configurations are building blocks for gadget drivers structured around 175 * function drivers. Simple USB gadgets require only one function and one 176 * configuration, and handle dual-speed hardware by always providing the same 177 * functionality. Slightly more complex gadgets may have more than one 178 * single-function configuration at a given speed; or have configurations 179 * that only work at one speed. 180 * 181 * Composite devices are, by definition, ones with configurations which 182 * include more than one function. 183 * 184 * The lifecycle of a usb_configuration includes allocation, initialization 185 * of the fields described above, and calling @usb_add_config() to set up 186 * internal data and bind it to a specific device. The configuration's 187 * @bind() method is then used to initialize all the functions and then 188 * call @usb_add_function() for them. 189 * 190 * Those functions would normally be independant of each other, but that's 191 * not mandatory. CDC WMC devices are an example where functions often 192 * depend on other functions, with some functions subsidiary to others. 193 * Such interdependency may be managed in any way, so long as all of the 194 * descriptors complete by the time the composite driver returns from 195 * its bind() routine. 196 */ 197 struct usb_configuration { 198 const char *label; 199 struct usb_gadget_strings **strings; 200 const struct usb_descriptor_header **descriptors; 201 202 /* REVISIT: bind() functions can be marked __init, which 203 * makes trouble for section mismatch analysis. See if 204 * we can't restructure things to avoid mismatching... 205 */ 206 207 /* configuration management: bind/unbind */ 208 int (*bind)(struct usb_configuration *); 209 void (*unbind)(struct usb_configuration *); 210 int (*setup)(struct usb_configuration *, 211 const struct usb_ctrlrequest *); 212 213 /* fields in the config descriptor */ 214 u8 bConfigurationValue; 215 u8 iConfiguration; 216 u8 bmAttributes; 217 u8 bMaxPower; 218 219 struct usb_composite_dev *cdev; 220 221 /* private: */ 222 /* internals */ 223 struct list_head list; 224 struct list_head functions; 225 u8 next_interface_id; 226 unsigned highspeed:1; 227 unsigned fullspeed:1; 228 struct usb_function *interface[MAX_CONFIG_INTERFACES]; 229 }; 230 231 int usb_add_config(struct usb_composite_dev *, 232 struct usb_configuration *); 233 234 /** 235 * struct usb_composite_driver - groups configurations into a gadget 236 * @name: For diagnostics, identifies the driver. 237 * @dev: Template descriptor for the device, including default device 238 * identifiers. 239 * @strings: tables of strings, keyed by identifiers assigned during bind() 240 * and language IDs provided in control requests 241 * @bind: (REQUIRED) Used to allocate resources that are shared across the 242 * whole device, such as string IDs, and add its configurations using 243 * @usb_add_config(). This may fail by returning a negative errno 244 * value; it should return zero on successful initialization. 245 * @unbind: Reverses @bind(); called as a side effect of unregistering 246 * this driver. 247 * @disconnect: optional driver disconnect method 248 * @suspend: Notifies when the host stops sending USB traffic, 249 * after function notifications 250 * @resume: Notifies configuration when the host restarts USB traffic, 251 * before function notifications 252 * 253 * Devices default to reporting self powered operation. Devices which rely 254 * on bus powered operation should report this in their @bind() method. 255 * 256 * Before returning from @bind, various fields in the template descriptor 257 * may be overridden. These include the idVendor/idProduct/bcdDevice values 258 * normally to bind the appropriate host side driver, and the three strings 259 * (iManufacturer, iProduct, iSerialNumber) normally used to provide user 260 * meaningful device identifiers. (The strings will not be defined unless 261 * they are defined in @dev and @strings.) The correct ep0 maxpacket size 262 * is also reported, as defined by the underlying controller driver. 263 */ 264 struct usb_composite_driver { 265 const char *name; 266 const struct usb_device_descriptor *dev; 267 struct usb_gadget_strings **strings; 268 269 /* REVISIT: bind() functions can be marked __init, which 270 * makes trouble for section mismatch analysis. See if 271 * we can't restructure things to avoid mismatching... 272 */ 273 274 int (*bind)(struct usb_composite_dev *); 275 int (*unbind)(struct usb_composite_dev *); 276 277 void (*disconnect)(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 unsigned int suspended:1; 330 struct usb_device_descriptor __aligned(CONFIG_SYS_CACHELINE_SIZE) desc; 331 struct list_head configs; 332 struct usb_composite_driver *driver; 333 u8 next_string_id; 334 335 /* the gadget driver won't enable the data pullup 336 * while the deactivation count is nonzero. 337 */ 338 unsigned deactivations; 339 }; 340 341 extern int usb_string_id(struct usb_composite_dev *c); 342 extern int usb_string_ids_tab(struct usb_composite_dev *c, 343 struct usb_string *str); 344 extern int usb_string_ids_n(struct usb_composite_dev *c, unsigned n); 345 346 #endif /* __LINUX_USB_COMPOSITE_H */ 347