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 *
ep_choose(struct usb_gadget * g,struct usb_endpoint_descriptor * hs,struct usb_endpoint_descriptor * fs)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