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1/*
2 * composite.h -- framework for usb gadgets which are composite devices
3 *
4 * Copyright (C) 2006-2008 David Brownell
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#ifndef __LINUX_USB_COMPOSITE_H
22#define __LINUX_USB_COMPOSITE_H
23
24/*
25 * This framework is an optional layer on top of the USB Gadget interface,
26 * making it easier to build (a) Composite devices, supporting multiple
27 * functions within any single configuration, and (b) Multi-configuration
28 * devices, also supporting multiple functions but without necessarily
29 * having more than one function per configuration.
30 *
31 * Example: a device with a single configuration supporting both network
32 * link and mass storage functions is a composite device. Those functions
33 * might alternatively be packaged in individual configurations, but in
34 * the composite model the host can use both functions at the same time.
35 */
36
37#include <linux/usb/ch9.h>
38#include <linux/usb/gadget.h>
39
40
41struct usb_configuration;
42
43/**
44 * struct usb_function - describes one function of a configuration
45 * @name: For diagnostics, identifies the function.
46 * @strings: tables of strings, keyed by identifiers assigned during bind()
47 * and by language IDs provided in control requests
48 * @descriptors: Table of full (or low) speed descriptors, using interface and
49 * string identifiers assigned during @bind(). If this pointer is null,
50 * the function will not be available at full speed (or at low speed).
51 * @hs_descriptors: Table of high speed descriptors, using interface and
52 * string identifiers assigned during @bind(). If this pointer is null,
53 * the function will not be available at high speed.
54 * @config: assigned when @usb_add_function() is called; this is the
55 * configuration with which this function is associated.
56 * @bind: Before the gadget can register, all of its functions bind() to the
57 * available resources including string and interface identifiers used
58 * in interface or class descriptors; endpoints; I/O buffers; and so on.
59 * @unbind: Reverses @bind; called as a side effect of unregistering the
60 * driver which added this function.
61 * @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may
62 * initialize usb_ep.driver data at this time (when it is used).
63 * Note that setting an interface to its current altsetting resets
64 * interface state, and that all interfaces have a disabled state.
65 * @get_alt: Returns the active altsetting. If this is not provided,
66 * then only altsetting zero is supported.
67 * @disable: (REQUIRED) Indicates the function should be disabled. Reasons
68 * include host resetting or reconfiguring the gadget, and disconnection.
69 * @setup: Used for interface-specific control requests.
70 * @suspend: Notifies functions when the host stops sending USB traffic.
71 * @resume: Notifies functions when the host restarts USB traffic.
72 *
73 * A single USB function uses one or more interfaces, and should in most
74 * cases support operation at both full and high speeds. Each function is
75 * associated by @usb_add_function() with a one configuration; that function
76 * causes @bind() to be called so resources can be allocated as part of
77 * setting up a gadget driver. Those resources include endpoints, which
78 * should be allocated using @usb_ep_autoconfig().
79 *
80 * To support dual speed operation, a function driver provides descriptors
81 * for both high and full speed operation. Except in rare cases that don't
82 * involve bulk endpoints, each speed needs different endpoint descriptors.
83 *
84 * Function drivers choose their own strategies for managing instance data.
85 * The simplest strategy just declares it "static', which means the function
86 * can only be activated once. If the function needs to be exposed in more
87 * than one configuration at a given speed, it needs to support multiple
88 * usb_function structures (one for each configuration).
89 *
90 * A more complex strategy might encapsulate a @usb_function structure inside
91 * a driver-specific instance structure to allows multiple activations. An
92 * example of multiple activations might be a CDC ACM function that supports
93 * two or more distinct instances within the same configuration, providing
94 * several independent logical data links to a USB host.
95 */
96struct usb_function {
97 const char *name;
98 struct usb_gadget_strings **strings;
99 struct usb_descriptor_header **descriptors;
100 struct usb_descriptor_header **hs_descriptors;
101
102 struct usb_configuration *config;
103
104 /* REVISIT: bind() functions can be marked __init, which
105 * makes trouble for section mismatch analysis. See if
106 * we can't restructure things to avoid mismatching.
107 * Related: unbind() may kfree() but bind() won't...
108 */
109
110 /* configuration management: bind/unbind */
111 int (*bind)(struct usb_configuration *,
112 struct usb_function *);
113 void (*unbind)(struct usb_configuration *,
114 struct usb_function *);
115
116 /* runtime state management */
117 int (*set_alt)(struct usb_function *,
118 unsigned interface, unsigned alt);
119 int (*get_alt)(struct usb_function *,
120 unsigned interface);
121 void (*disable)(struct usb_function *);
122 int (*setup)(struct usb_function *,
123 const struct usb_ctrlrequest *);
124 void (*suspend)(struct usb_function *);
125 void (*resume)(struct usb_function *);
126
cac85a8b 127 /* private: */
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128 /* internals */
129 struct list_head list;
5242658d 130 DECLARE_BITMAP(endpoints, 32);
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131};
132
133int usb_add_function(struct usb_configuration *, struct usb_function *);
134
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135int usb_function_deactivate(struct usb_function *);
136int usb_function_activate(struct usb_function *);
137
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138int usb_interface_id(struct usb_configuration *, struct usb_function *);
139
140/**
141 * ep_choose - select descriptor endpoint at current device speed
142 * @g: gadget, connected and running at some speed
143 * @hs: descriptor to use for high speed operation
144 * @fs: descriptor to use for full or low speed operation
145 */
146static inline struct usb_endpoint_descriptor *
147ep_choose(struct usb_gadget *g, struct usb_endpoint_descriptor *hs,
148 struct usb_endpoint_descriptor *fs)
149{
150 if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
151 return hs;
152 return fs;
153}
154
155#define MAX_CONFIG_INTERFACES 16 /* arbitrary; max 255 */
156
157/**
158 * struct usb_configuration - represents one gadget configuration
159 * @label: For diagnostics, describes the configuration.
160 * @strings: Tables of strings, keyed by identifiers assigned during @bind()
161 * and by language IDs provided in control requests.
162 * @descriptors: Table of descriptors preceding all function descriptors.
163 * Examples include OTG and vendor-specific descriptors.
164 * @bind: Called from @usb_add_config() to allocate resources unique to this
165 * configuration and to call @usb_add_function() for each function used.
166 * @unbind: Reverses @bind; called as a side effect of unregistering the
167 * driver which added this configuration.
168 * @setup: Used to delegate control requests that aren't handled by standard
169 * device infrastructure or directed at a specific interface.
170 * @bConfigurationValue: Copied into configuration descriptor.
171 * @iConfiguration: Copied into configuration descriptor.
172 * @bmAttributes: Copied into configuration descriptor.
173 * @bMaxPower: Copied into configuration descriptor.
174 * @cdev: assigned by @usb_add_config() before calling @bind(); this is
175 * the device associated with this configuration.
176 *
177 * Configurations are building blocks for gadget drivers structured around
178 * function drivers. Simple USB gadgets require only one function and one
179 * configuration, and handle dual-speed hardware by always providing the same
180 * functionality. Slightly more complex gadgets may have more than one
181 * single-function configuration at a given speed; or have configurations
182 * that only work at one speed.
183 *
184 * Composite devices are, by definition, ones with configurations which
185 * include more than one function.
186 *
187 * The lifecycle of a usb_configuration includes allocation, initialization
188 * of the fields described above, and calling @usb_add_config() to set up
189 * internal data and bind it to a specific device. The configuration's
190 * @bind() method is then used to initialize all the functions and then
191 * call @usb_add_function() for them.
192 *
193 * Those functions would normally be independant of each other, but that's
194 * not mandatory. CDC WMC devices are an example where functions often
195 * depend on other functions, with some functions subsidiary to others.
196 * Such interdependency may be managed in any way, so long as all of the
197 * descriptors complete by the time the composite driver returns from
198 * its bind() routine.
199 */
200struct usb_configuration {
201 const char *label;
202 struct usb_gadget_strings **strings;
203 const struct usb_descriptor_header **descriptors;
204
205 /* REVISIT: bind() functions can be marked __init, which
206 * makes trouble for section mismatch analysis. See if
207 * we can't restructure things to avoid mismatching...
208 */
209
210 /* configuration management: bind/unbind */
211 int (*bind)(struct usb_configuration *);
212 void (*unbind)(struct usb_configuration *);
213 int (*setup)(struct usb_configuration *,
214 const struct usb_ctrlrequest *);
215
216 /* fields in the config descriptor */
217 u8 bConfigurationValue;
218 u8 iConfiguration;
219 u8 bmAttributes;
220 u8 bMaxPower;
221
222 struct usb_composite_dev *cdev;
223
cac85a8b 224 /* private: */
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225 /* internals */
226 struct list_head list;
227 struct list_head functions;
228 u8 next_interface_id;
229 unsigned highspeed:1;
230 unsigned fullspeed:1;
231 struct usb_function *interface[MAX_CONFIG_INTERFACES];
232};
233
234int usb_add_config(struct usb_composite_dev *,
235 struct usb_configuration *);
236
237/**
238 * struct usb_composite_driver - groups configurations into a gadget
239 * @name: For diagnostics, identifies the driver.
240 * @dev: Template descriptor for the device, including default device
241 * identifiers.
242 * @strings: tables of strings, keyed by identifiers assigned during bind()
243 * and language IDs provided in control requests
244 * @bind: (REQUIRED) Used to allocate resources that are shared across the
245 * whole device, such as string IDs, and add its configurations using
246 * @usb_add_config(). This may fail by returning a negative errno
247 * value; it should return zero on successful initialization.
248 * @unbind: Reverses @bind(); called as a side effect of unregistering
249 * this driver.
d187abb9 250 * @disconnect: optional driver disconnect method
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251 * @suspend: Notifies when the host stops sending USB traffic,
252 * after function notifications
253 * @resume: Notifies configuration when the host restarts USB traffic,
254 * before function notifications
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255 *
256 * Devices default to reporting self powered operation. Devices which rely
257 * on bus powered operation should report this in their @bind() method.
258 *
259 * Before returning from @bind, various fields in the template descriptor
260 * may be overridden. These include the idVendor/idProduct/bcdDevice values
261 * normally to bind the appropriate host side driver, and the three strings
262 * (iManufacturer, iProduct, iSerialNumber) normally used to provide user
263 * meaningful device identifiers. (The strings will not be defined unless
264 * they are defined in @dev and @strings.) The correct ep0 maxpacket size
265 * is also reported, as defined by the underlying controller driver.
266 */
267struct usb_composite_driver {
268 const char *name;
269 const struct usb_device_descriptor *dev;
270 struct usb_gadget_strings **strings;
271
272 /* REVISIT: bind() functions can be marked __init, which
273 * makes trouble for section mismatch analysis. See if
274 * we can't restructure things to avoid mismatching...
275 */
276
277 int (*bind)(struct usb_composite_dev *);
278 int (*unbind)(struct usb_composite_dev *);
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279
280 void (*disconnect)(struct usb_composite_dev *);
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281
282 /* global suspend hooks */
283 void (*suspend)(struct usb_composite_dev *);
284 void (*resume)(struct usb_composite_dev *);
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285};
286
287extern int usb_composite_register(struct usb_composite_driver *);
288extern void usb_composite_unregister(struct usb_composite_driver *);
289
290
291/**
292 * struct usb_composite_device - represents one composite usb gadget
293 * @gadget: read-only, abstracts the gadget's usb peripheral controller
294 * @req: used for control responses; buffer is pre-allocated
295 * @bufsiz: size of buffer pre-allocated in @req
296 * @config: the currently active configuration
297 *
298 * One of these devices is allocated and initialized before the
299 * associated device driver's bind() is called.
300 *
301 * OPEN ISSUE: it appears that some WUSB devices will need to be
302 * built by combining a normal (wired) gadget with a wireless one.
303 * This revision of the gadget framework should probably try to make
304 * sure doing that won't hurt too much.
305 *
306 * One notion for how to handle Wireless USB devices involves:
307 * (a) a second gadget here, discovery mechanism TBD, but likely
308 * needing separate "register/unregister WUSB gadget" calls;
309 * (b) updates to usb_gadget to include flags "is it wireless",
310 * "is it wired", plus (presumably in a wrapper structure)
311 * bandgroup and PHY info;
312 * (c) presumably a wireless_ep wrapping a usb_ep, and reporting
313 * wireless-specific parameters like maxburst and maxsequence;
314 * (d) configurations that are specific to wireless links;
315 * (e) function drivers that understand wireless configs and will
316 * support wireless for (additional) function instances;
317 * (f) a function to support association setup (like CBAF), not
318 * necessarily requiring a wireless adapter;
319 * (g) composite device setup that can create one or more wireless
320 * configs, including appropriate association setup support;
321 * (h) more, TBD.
322 */
323struct usb_composite_dev {
324 struct usb_gadget *gadget;
325 struct usb_request *req;
326 unsigned bufsiz;
327
328 struct usb_configuration *config;
329
cac85a8b 330 /* private: */
40982be5 331 /* internals */
f48cf80f 332 unsigned int suspended:1;
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333 struct usb_device_descriptor desc;
334 struct list_head configs;
335 struct usb_composite_driver *driver;
336 u8 next_string_id;
337
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338 /* the gadget driver won't enable the data pullup
339 * while the deactivation count is nonzero.
340 */
341 unsigned deactivations;
40982be5 342
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343 /* protects at least deactivation count */
344 spinlock_t lock;
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345};
346
347extern int usb_string_id(struct usb_composite_dev *c);
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348extern int usb_string_ids_tab(struct usb_composite_dev *c,
349 struct usb_string *str);
350extern int usb_string_ids_n(struct usb_composite_dev *c, unsigned n);
351
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352
353/* messaging utils */
354#define DBG(d, fmt, args...) \
355 dev_dbg(&(d)->gadget->dev , fmt , ## args)
356#define VDBG(d, fmt, args...) \
357 dev_vdbg(&(d)->gadget->dev , fmt , ## args)
358#define ERROR(d, fmt, args...) \
359 dev_err(&(d)->gadget->dev , fmt , ## args)
b6c63937 360#define WARNING(d, fmt, args...) \
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361 dev_warn(&(d)->gadget->dev , fmt , ## args)
362#define INFO(d, fmt, args...) \
363 dev_info(&(d)->gadget->dev , fmt , ## args)
364
365#endif /* __LINUX_USB_COMPOSITE_H */