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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