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
41 struct 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 */
96 struct 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
127 /* internals */
128 struct list_head list;
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 *
ep_choose(struct usb_gadget * g,struct usb_endpoint_descriptor * hs,struct usb_endpoint_descriptor * fs)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 /* 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 *
248 * Devices default to reporting self powered operation. Devices which rely
249 * on bus powered operation should report this in their @bind() method.
250 *
251 * Before returning from @bind, various fields in the template descriptor
252 * may be overridden. These include the idVendor/idProduct/bcdDevice values
253 * normally to bind the appropriate host side driver, and the three strings
254 * (iManufacturer, iProduct, iSerialNumber) normally used to provide user
255 * meaningful device identifiers. (The strings will not be defined unless
256 * they are defined in @dev and @strings.) The correct ep0 maxpacket size
257 * is also reported, as defined by the underlying controller driver.
258 */
259 struct usb_composite_driver {
260 const char *name;
261 const struct usb_device_descriptor *dev;
262 struct usb_gadget_strings **strings;
263
264 /* REVISIT: bind() functions can be marked __init, which
265 * makes trouble for section mismatch analysis. See if
266 * we can't restructure things to avoid mismatching...
267 */
268
269 int (*bind)(struct usb_composite_dev *);
270 int (*unbind)(struct usb_composite_dev *);
271 };
272
273 extern int usb_composite_register(struct usb_composite_driver *);
274 extern void usb_composite_unregister(struct usb_composite_driver *);
275
276
277 /**
278 * struct usb_composite_device - represents one composite usb gadget
279 * @gadget: read-only, abstracts the gadget's usb peripheral controller
280 * @req: used for control responses; buffer is pre-allocated
281 * @bufsiz: size of buffer pre-allocated in @req
282 * @config: the currently active configuration
283 *
284 * One of these devices is allocated and initialized before the
285 * associated device driver's bind() is called.
286 *
287 * OPEN ISSUE: it appears that some WUSB devices will need to be
288 * built by combining a normal (wired) gadget with a wireless one.
289 * This revision of the gadget framework should probably try to make
290 * sure doing that won't hurt too much.
291 *
292 * One notion for how to handle Wireless USB devices involves:
293 * (a) a second gadget here, discovery mechanism TBD, but likely
294 * needing separate "register/unregister WUSB gadget" calls;
295 * (b) updates to usb_gadget to include flags "is it wireless",
296 * "is it wired", plus (presumably in a wrapper structure)
297 * bandgroup and PHY info;
298 * (c) presumably a wireless_ep wrapping a usb_ep, and reporting
299 * wireless-specific parameters like maxburst and maxsequence;
300 * (d) configurations that are specific to wireless links;
301 * (e) function drivers that understand wireless configs and will
302 * support wireless for (additional) function instances;
303 * (f) a function to support association setup (like CBAF), not
304 * necessarily requiring a wireless adapter;
305 * (g) composite device setup that can create one or more wireless
306 * configs, including appropriate association setup support;
307 * (h) more, TBD.
308 */
309 struct usb_composite_dev {
310 struct usb_gadget *gadget;
311 struct usb_request *req;
312 unsigned bufsiz;
313
314 struct usb_configuration *config;
315
316 /* internals */
317 struct usb_device_descriptor desc;
318 struct list_head configs;
319 struct usb_composite_driver *driver;
320 u8 next_string_id;
321
322 /* the gadget driver won't enable the data pullup
323 * while the deactivation count is nonzero.
324 */
325 unsigned deactivations;
326
327 /* protects at least deactivation count */
328 spinlock_t lock;
329 };
330
331 extern int usb_string_id(struct usb_composite_dev *c);
332
333 /* messaging utils */
334 #define DBG(d, fmt, args...) \
335 dev_dbg(&(d)->gadget->dev , fmt , ## args)
336 #define VDBG(d, fmt, args...) \
337 dev_vdbg(&(d)->gadget->dev , fmt , ## args)
338 #define ERROR(d, fmt, args...) \
339 dev_err(&(d)->gadget->dev , fmt , ## args)
340 #define WARNING(d, fmt, args...) \
341 dev_warn(&(d)->gadget->dev , fmt , ## args)
342 #define INFO(d, fmt, args...) \
343 dev_info(&(d)->gadget->dev , fmt , ## args)
344
345 #endif /* __LINUX_USB_COMPOSITE_H */
346