summaryrefslogtreecommitdiff
path: root/drivers/usb/gadget/function/u_fs.h
blob: 4b6969451cdc28dcfabb4db8806a403df1199e0d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
/*
 * u_fs.h
 *
 * Utility definitions for the FunctionFS
 *
 * Copyright (c) 2013 Samsung Electronics Co., Ltd.
 *		http://www.samsung.com
 *
 * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#ifndef U_FFS_H
#define U_FFS_H

#include <linux/usb/composite.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/workqueue.h>

#ifdef VERBOSE_DEBUG
#ifndef pr_vdebug
#  define pr_vdebug pr_debug
#endif /* pr_vdebug */
#  define ffs_dump_mem(prefix, ptr, len) \
	print_hex_dump_bytes(pr_fmt(prefix ": "), DUMP_PREFIX_NONE, ptr, len)
#else
#ifndef pr_vdebug
#  define pr_vdebug(...)                 do { } while (0)
#endif /* pr_vdebug */
#  define ffs_dump_mem(prefix, ptr, len) do { } while (0)
#endif /* VERBOSE_DEBUG */

#define ENTER()    pr_vdebug("%s()\n", __func__)

struct f_fs_opts;

struct ffs_dev {
	const char *name;
	bool name_allocated;
	bool mounted;
	bool desc_ready;
	bool single;
	struct ffs_data *ffs_data;
	struct f_fs_opts *opts;
	struct list_head entry;

	int (*ffs_ready_callback)(struct ffs_data *ffs);
	void (*ffs_closed_callback)(struct ffs_data *ffs);
	void *(*ffs_acquire_dev_callback)(struct ffs_dev *dev);
	void (*ffs_release_dev_callback)(struct ffs_dev *dev);
};

extern struct mutex ffs_lock;

static inline void ffs_dev_lock(void)
{
	mutex_lock(&ffs_lock);
}

static inline void ffs_dev_unlock(void)
{
	mutex_unlock(&ffs_lock);
}

int ffs_name_dev(struct ffs_dev *dev, const char *name);
int ffs_single_dev(struct ffs_dev *dev);

struct ffs_epfile;
struct ffs_function;

enum ffs_state {
	/*
	 * Waiting for descriptors and strings.
	 *
	 * In this state no open(2), read(2) or write(2) on epfiles
	 * may succeed (which should not be the problem as there
	 * should be no such files opened in the first place).
	 */
	FFS_READ_DESCRIPTORS,
	FFS_READ_STRINGS,

	/*
	 * We've got descriptors and strings.  We are or have called
	 * functionfs_ready_callback().  functionfs_bind() may have
	 * been called but we don't know.
	 *
	 * This is the only state in which operations on epfiles may
	 * succeed.
	 */
	FFS_ACTIVE,

	/*
	 * Function is visible to host, but it's not functional. All
	 * setup requests are stalled and transfers on another endpoints
	 * are refused. All epfiles, except ep0, are deleted so there
	 * is no way to perform any operations on them.
	 *
	 * This state is set after closing all functionfs files, when
	 * mount parameter "no_disconnect=1" has been set. Function will
	 * remain in deactivated state until filesystem is umounted or
	 * ep0 is opened again. In the second case functionfs state will
	 * be reset, and it will be ready for descriptors and strings
	 * writing.
	 *
	 * This is useful only when functionfs is composed to gadget
	 * with another function which can perform some critical
	 * operations, and it's strongly desired to have this operations
	 * completed, even after functionfs files closure.
	 */
	FFS_DEACTIVATED,

	/*
	 * All endpoints have been closed.  This state is also set if
	 * we encounter an unrecoverable error.  The only
	 * unrecoverable error is situation when after reading strings
	 * from user space we fail to initialise epfiles or
	 * functionfs_ready_callback() returns with error (<0).
	 *
	 * In this state no open(2), read(2) or write(2) (both on ep0
	 * as well as epfile) may succeed (at this point epfiles are
	 * unlinked and all closed so this is not a problem; ep0 is
	 * also closed but ep0 file exists and so open(2) on ep0 must
	 * fail).
	 */
	FFS_CLOSING
};

enum ffs_setup_state {
	/* There is no setup request pending. */
	FFS_NO_SETUP,
	/*
	 * User has read events and there was a setup request event
	 * there.  The next read/write on ep0 will handle the
	 * request.
	 */
	FFS_SETUP_PENDING,
	/*
	 * There was event pending but before user space handled it
	 * some other event was introduced which canceled existing
	 * setup.  If this state is set read/write on ep0 return
	 * -EIDRM.  This state is only set when adding event.
	 */
	FFS_SETUP_CANCELLED
};

struct ffs_data {
	struct usb_gadget		*gadget;

	/*
	 * Protect access read/write operations, only one read/write
	 * at a time.  As a consequence protects ep0req and company.
	 * While setup request is being processed (queued) this is
	 * held.
	 */
	struct mutex			mutex;

	/*
	 * Protect access to endpoint related structures (basically
	 * usb_ep_queue(), usb_ep_dequeue(), etc. calls) except for
	 * endpoint zero.
	 */
	spinlock_t			eps_lock;

	/*
	 * XXX REVISIT do we need our own request? Since we are not
	 * handling setup requests immediately user space may be so
	 * slow that another setup will be sent to the gadget but this
	 * time not to us but another function and then there could be
	 * a race.  Is that the case? Or maybe we can use cdev->req
	 * after all, maybe we just need some spinlock for that?
	 */
	struct usb_request		*ep0req;		/* P: mutex */
	struct completion		ep0req_completion;	/* P: mutex */

	/* reference counter */
	atomic_t			ref;
	/* how many files are opened (EP0 and others) */
	atomic_t			opened;

	/* EP0 state */
	enum ffs_state			state;

	/*
	 * Possible transitions:
	 * + FFS_NO_SETUP        -> FFS_SETUP_PENDING  -- P: ev.waitq.lock
	 *               happens only in ep0 read which is P: mutex
	 * + FFS_SETUP_PENDING   -> FFS_NO_SETUP       -- P: ev.waitq.lock
	 *               happens only in ep0 i/o  which is P: mutex
	 * + FFS_SETUP_PENDING   -> FFS_SETUP_CANCELLED -- P: ev.waitq.lock
	 * + FFS_SETUP_CANCELLED -> FFS_NO_SETUP        -- cmpxchg
	 *
	 * This field should never be accessed directly and instead
	 * ffs_setup_state_clear_cancelled function should be used.
	 */
	enum ffs_setup_state		setup_state;

	/* Events & such. */
	struct {
		u8				types[4];
		unsigned short			count;
		/* XXX REVISIT need to update it in some places, or do we? */
		unsigned short			can_stall;
		struct usb_ctrlrequest		setup;

		wait_queue_head_t		waitq;
	} ev; /* the whole structure, P: ev.waitq.lock */

	/* Flags */
	unsigned long			flags;
#define FFS_FL_CALL_CLOSED_CALLBACK 0
#define FFS_FL_BOUND                1

	/* Active function */
	struct ffs_function		*func;

	/*
	 * Device name, write once when file system is mounted.
	 * Intended for user to read if she wants.
	 */
	const char			*dev_name;
	/* Private data for our user (ie. gadget).  Managed by user. */
	void				*private_data;

	/* filled by __ffs_data_got_descs() */
	/*
	 * raw_descs is what you kfree, real_descs points inside of raw_descs,
	 * where full speed, high speed and super speed descriptors start.
	 * real_descs_length is the length of all those descriptors.
	 */
	const void			*raw_descs_data;
	const void			*raw_descs;
	unsigned			raw_descs_length;
	unsigned			fs_descs_count;
	unsigned			hs_descs_count;
	unsigned			ss_descs_count;
	unsigned			ms_os_descs_count;
	unsigned			ms_os_descs_ext_prop_count;
	unsigned			ms_os_descs_ext_prop_name_len;
	unsigned			ms_os_descs_ext_prop_data_len;
	void				*ms_os_descs_ext_prop_avail;
	void				*ms_os_descs_ext_prop_name_avail;
	void				*ms_os_descs_ext_prop_data_avail;

	unsigned			user_flags;

#define FFS_MAX_EPS_COUNT 31
	u8				eps_addrmap[FFS_MAX_EPS_COUNT];

	unsigned short			strings_count;
	unsigned short			interfaces_count;
	unsigned short			eps_count;
	unsigned short			_pad1;

	/* filled by __ffs_data_got_strings() */
	/* ids in stringtabs are set in functionfs_bind() */
	const void			*raw_strings;
	struct usb_gadget_strings	**stringtabs;

	/*
	 * File system's super block, write once when file system is
	 * mounted.
	 */
	struct super_block		*sb;

	/* File permissions, written once when fs is mounted */
	struct ffs_file_perms {
		umode_t				mode;
		kuid_t				uid;
		kgid_t				gid;
	}				file_perms;

	struct eventfd_ctx *ffs_eventfd;
	bool no_disconnect;
	struct work_struct reset_work;

	/*
	 * The endpoint files, filled by ffs_epfiles_create(),
	 * destroyed by ffs_epfiles_destroy().
	 */
	struct ffs_epfile		*epfiles;
};


struct f_fs_opts {
	struct usb_function_instance	func_inst;
	struct ffs_dev			*dev;
	unsigned			refcnt;
	bool				no_configfs;
};

static inline struct f_fs_opts *to_f_fs_opts(struct usb_function_instance *fi)
{
	return container_of(fi, struct f_fs_opts, func_inst);
}

#endif /* U_FFS_H */