aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/tty_driver.h
blob: 59f1c0bd8f9c6f8734a1320185a3eb28a9b29990 (plain) (blame)
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
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
#ifndef _LINUX_TTY_DRIVER_H
#define _LINUX_TTY_DRIVER_H

/*
 * This structure defines the interface between the low-level tty
 * driver and the tty routines.  The following routines can be
 * defined; unless noted otherwise, they are optional, and can be
 * filled in with a null pointer.
 *
 * int  (*open)(struct tty_struct * tty, struct file * filp);
 *
 * 	This routine is called when a particular tty device is opened.
 * 	This routine is mandatory; if this routine is not filled in,
 * 	the attempted open will fail with ENODEV.
 *
 *	Required method.
 *     
 * void (*close)(struct tty_struct * tty, struct file * filp);
 *
 * 	This routine is called when a particular tty device is closed.
 *
 *	Required method.
 *
 * int (*write)(struct tty_struct * tty,
 * 		 const unsigned char *buf, int count);
 *
 * 	This routine is called by the kernel to write a series of
 * 	characters to the tty device.  The characters may come from
 * 	user space or kernel space.  This routine will return the
 *	number of characters actually accepted for writing.  This
 *	routine is mandatory.
 *
 *	Optional: Required for writable devices.
 *
 * int (*put_char)(struct tty_struct *tty, unsigned char ch);
 *
 * 	This routine is called by the kernel to write a single
 * 	character to the tty device.  If the kernel uses this routine,
 * 	it must call the flush_chars() routine (if defined) when it is
 * 	done stuffing characters into the driver.  If there is no room
 * 	in the queue, the character is ignored.
 *
 *	Optional: Kernel will use the write method if not provided.
 *
 *	Note: Do not call this function directly, call tty_put_char
 *
 * void (*flush_chars)(struct tty_struct *tty);
 *
 * 	This routine is called by the kernel after it has written a
 * 	series of characters to the tty device using put_char().  
 *
 *	Optional:
 *
 *	Note: Do not call this function directly, call tty_driver_flush_chars
 * 
 * int  (*write_room)(struct tty_struct *tty);
 *
 * 	This routine returns the numbers of characters the tty driver
 * 	will accept for queuing to be written.  This number is subject
 * 	to change as output buffers get emptied, or if the output flow
 *	control is acted.
 *
 *	Required if write method is provided else not needed.
 *
 *	Note: Do not call this function directly, call tty_write_room
 * 
 * int  (*ioctl)(struct tty_struct *tty, struct file * file,
 * 	    unsigned int cmd, unsigned long arg);
 *
 * 	This routine allows the tty driver to implement
 *	device-specific ioctl's.  If the ioctl number passed in cmd
 * 	is not recognized by the driver, it should return ENOIOCTLCMD.
 *
 *	Optional
 *
 * long (*compat_ioctl)(struct tty_struct *tty, struct file * file,
 * 	                unsigned int cmd, unsigned long arg);
 *
 * 	implement ioctl processing for 32 bit process on 64 bit system
 *
 *	Optional
 * 
 * void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
 *
 * 	This routine allows the tty driver to be notified when
 * 	device's termios settings have changed.
 *
 *	Optional: Called under the termios lock
 *
 *
 * void (*set_ldisc)(struct tty_struct *tty);
 *
 * 	This routine allows the tty driver to be notified when the
 * 	device's termios settings have changed.
 *
 *	Optional: Called under BKL (currently)
 * 
 * void (*throttle)(struct tty_struct * tty);
 *
 * 	This routine notifies the tty driver that input buffers for
 * 	the line discipline are close to full, and it should somehow
 * 	signal that no more characters should be sent to the tty.
 *
 *	Optional: Always invoke via tty_throttle();
 * 
 * void (*unthrottle)(struct tty_struct * tty);
 *
 * 	This routine notifies the tty drivers that it should signals
 * 	that characters can now be sent to the tty without fear of
 * 	overrunning the input buffers of the line disciplines.
 * 
 *	Optional: Always invoke via tty_unthrottle();
 *
 * void (*stop)(struct tty_struct *tty);
 *
 * 	This routine notifies the tty driver that it should stop
 * 	outputting characters to the tty device.  
 *
 *	Optional:
 *
 *	Note: Call stop_tty not this method.
 * 
 * void (*start)(struct tty_struct *tty);
 *
 * 	This routine notifies the tty driver that it resume sending
 *	characters to the tty device.
 *
 *	Optional:
 *
 *	Note: Call start_tty not this method.
 * 
 * void (*hangup)(struct tty_struct *tty);
 *
 * 	This routine notifies the tty driver that it should hangup the
 * 	tty device.
 *
 *	Required:
 *
 * void (*break_ctl)(struct tty_stuct *tty, int state);
 *
 * 	This optional routine requests the tty driver to turn on or
 * 	off BREAK status on the RS-232 port.  If state is -1,
 * 	then the BREAK status should be turned on; if state is 0, then
 * 	BREAK should be turned off.
 *
 * 	If this routine is implemented, the high-level tty driver will
 * 	handle the following ioctls: TCSBRK, TCSBRKP, TIOCSBRK,
 * 	TIOCCBRK.
 *
 *	Optional: Required for TCSBRK/BRKP/etc handling.
 *
 * void (*wait_until_sent)(struct tty_struct *tty, int timeout);
 * 
 * 	This routine waits until the device has written out all of the
 * 	characters in its transmitter FIFO.
 *
 *	Optional: If not provided the device is assumed to have no FIFO
 *
 *	Note: Usually correct to call tty_wait_until_sent
 *
 * void (*send_xchar)(struct tty_struct *tty, char ch);
 *
 * 	This routine is used to send a high-priority XON/XOFF
 * 	character to the device.
 *
 *	Optional: If not provided then the write method is called under
 *	the atomic write lock to keep it serialized with the ldisc.
 */

#include <linux/fs.h>
#include <linux/list.h>
#include <linux/cdev.h>

struct tty_struct;
struct tty_driver;

struct tty_operations {
	int  (*open)(struct tty_struct * tty, struct file * filp);
	void (*close)(struct tty_struct * tty, struct file * filp);
	int  (*write)(struct tty_struct * tty,
		      const unsigned char *buf, int count);
	int  (*put_char)(struct tty_struct *tty, unsigned char ch);
	void (*flush_chars)(struct tty_struct *tty);
	int  (*write_room)(struct tty_struct *tty);
	int  (*chars_in_buffer)(struct tty_struct *tty);
	int  (*ioctl)(struct tty_struct *tty, struct file * file,
		    unsigned int cmd, unsigned long arg);
	long (*compat_ioctl)(struct tty_struct *tty, struct file * file,
			     unsigned int cmd, unsigned long arg);
	void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
	void (*throttle)(struct tty_struct * tty);
	void (*unthrottle)(struct tty_struct * tty);
	void (*stop)(struct tty_struct *tty);
	void (*start)(struct tty_struct *tty);
	void (*hangup)(struct tty_struct *tty);
	void (*break_ctl)(struct tty_struct *tty, int state);
	void (*flush_buffer)(struct tty_struct *tty);
	void (*set_ldisc)(struct tty_struct *tty);
	void (*wait_until_sent)(struct tty_struct *tty, int timeout);
	void (*send_xchar)(struct tty_struct *tty, char ch);
	int (*read_proc)(char *page, char **start, off_t off,
			  int count, int *eof, void *data);
	int (*tiocmget)(struct tty_struct *tty, struct file *file);
	int (*tiocmset)(struct tty_struct *tty, struct file *file,
			unsigned int set, unsigned int clear);
#ifdef CONFIG_CONSOLE_POLL
	int (*poll_init)(struct tty_driver *driver, int line, char *options);
	int (*poll_get_char)(struct tty_driver *driver, int line);
	void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
#endif
};

struct tty_driver {
	int	magic;		/* magic number for this structure */
	struct cdev cdev;
	struct module	*owner;
	const char	*driver_name;
	const char	*name;
	int	name_base;	/* offset of printed name */
	int	major;		/* major device number */
	int	minor_start;	/* start of minor device number */
	int	minor_num;	/* number of *possible* devices */
	int	num;		/* number of devices allocated */
	short	type;		/* type of tty driver */
	short	subtype;	/* subtype of tty driver */
	struct ktermios init_termios; /* Initial termios */
	int	flags;		/* tty driver flags */
	int	refcount;	/* for loadable tty drivers */
	struct proc_dir_entry *proc_entry; /* /proc fs entry */
	struct tty_driver *other; /* only used for the PTY driver */

	/*
	 * Pointer to the tty data structures
	 */
	struct tty_struct **ttys;
	struct ktermios **termios;
	struct ktermios **termios_locked;
	void *driver_state;

	/*
	 * Driver methods
	 */

	const struct tty_operations *ops;
	struct list_head tty_drivers;
};

extern struct list_head tty_drivers;

struct tty_driver *alloc_tty_driver(int lines);
void put_tty_driver(struct tty_driver *driver);
void tty_set_operations(struct tty_driver *driver,
			const struct tty_operations *op);
extern struct tty_driver *tty_find_polling_driver(char *name, int *line);

/* tty driver magic number */
#define TTY_DRIVER_MAGIC		0x5402

/*
 * tty driver flags
 * 
 * TTY_DRIVER_RESET_TERMIOS --- requests the tty layer to reset the
 * 	termios setting when the last process has closed the device.
 * 	Used for PTY's, in particular.
 * 
 * TTY_DRIVER_REAL_RAW --- if set, indicates that the driver will
 * 	guarantee never not to set any special character handling
 * 	flags if ((IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR ||
 * 	!INPCK)).  That is, if there is no reason for the driver to
 * 	send notifications of parity and break characters up to the
 * 	line driver, it won't do so.  This allows the line driver to
 *	optimize for this case if this flag is set.  (Note that there
 * 	is also a promise, if the above case is true, not to signal
 * 	overruns, either.)
 *
 * TTY_DRIVER_DYNAMIC_DEV --- if set, the individual tty devices need
 *	to be registered with a call to tty_register_driver() when the
 *	device is found in the system and unregistered with a call to
 *	tty_unregister_device() so the devices will be show up
 *	properly in sysfs.  If not set, driver->num entries will be
 *	created by the tty core in sysfs when tty_register_driver() is
 *	called.  This is to be used by drivers that have tty devices
 *	that can appear and disappear while the main tty driver is
 *	registered with the tty core.
 *
 * TTY_DRIVER_DEVPTS_MEM -- don't use the standard arrays, instead
 *	use dynamic memory keyed through the devpts filesystem.  This
 *	is only applicable to the pty driver.
 */
#define TTY_DRIVER_INSTALLED		0x0001
#define TTY_DRIVER_RESET_TERMIOS	0x0002
#define TTY_DRIVER_REAL_RAW		0x0004
#define TTY_DRIVER_DYNAMIC_DEV		0x0008
#define TTY_DRIVER_DEVPTS_MEM		0x0010

/* tty driver types */
#define TTY_DRIVER_TYPE_SYSTEM		0x0001
#define TTY_DRIVER_TYPE_CONSOLE		0x0002
#define TTY_DRIVER_TYPE_SERIAL		0x0003
#define TTY_DRIVER_TYPE_PTY		0x0004
#define TTY_DRIVER_TYPE_SCC		0x0005	/* scc driver */
#define TTY_DRIVER_TYPE_SYSCONS		0x0006

/* system subtypes (magic, used by tty_io.c) */
#define SYSTEM_TYPE_TTY			0x0001
#define SYSTEM_TYPE_CONSOLE		0x0002
#define SYSTEM_TYPE_SYSCONS		0x0003
#define SYSTEM_TYPE_SYSPTMX		0x0004

/* pty subtypes (magic, used by tty_io.c) */
#define PTY_TYPE_MASTER			0x0001
#define PTY_TYPE_SLAVE			0x0002

/* serial subtype definitions */
#define SERIAL_TYPE_NORMAL	1

#endif /* #ifdef _LINUX_TTY_DRIVER_H */