1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_TTY_DRIVER_H
3 #define _LINUX_TTY_DRIVER_H
4 
5 #include <linux/export.h>
6 #include <linux/fs.h>
7 #include <linux/kref.h>
8 #include <linux/list.h>
9 #include <linux/cdev.h>
10 #include <linux/uaccess.h>
11 #include <linux/termios.h>
12 #include <linux/seq_file.h>
13 
14 struct tty_struct;
15 struct tty_driver;
16 struct serial_icounter_struct;
17 struct serial_struct;
18 
19 /**
20  * struct tty_operations -- interface between driver and tty
21  *
22  * @lookup: ``struct tty_struct *()(struct tty_driver *self, struct file *,
23  *				    int idx)``
24  *
25  *	Return the tty device corresponding to @idx, %NULL if there is not
26  *	one currently in use and an %ERR_PTR value on error. Called under
27  *	%tty_mutex (for now!)
28  *
29  *	Optional method. Default behaviour is to use the @self->ttys array.
30  *
31  * @install: ``int ()(struct tty_driver *self, struct tty_struct *tty)``
32  *
33  *	Install a new @tty into the @self's internal tables. Used in
34  *	conjunction with @lookup and @remove methods.
35  *
36  *	Optional method. Default behaviour is to use the @self->ttys array.
37  *
38  * @remove: ``void ()(struct tty_driver *self, struct tty_struct *tty)``
39  *
40  *	Remove a closed @tty from the @self's internal tables. Used in
41  *	conjunction with @lookup and @remove methods.
42  *
43  *	Optional method. Default behaviour is to use the @self->ttys array.
44  *
45  * @open: ``int ()(struct tty_struct *tty, struct file *)``
46  *
47  *	This routine is called when a particular @tty device is opened. This
48  *	routine is mandatory; if this routine is not filled in, the attempted
49  *	open will fail with %ENODEV.
50  *
51  *	Required method. Called with tty lock held. May sleep.
52  *
53  * @close: ``void ()(struct tty_struct *tty, struct file *)``
54  *
55  *	This routine is called when a particular @tty device is closed. At the
56  *	point of return from this call the driver must make no further ldisc
57  *	calls of any kind.
58  *
59  *	Remark: called even if the corresponding @open() failed.
60  *
61  *	Required method. Called with tty lock held. May sleep.
62  *
63  * @shutdown: ``void ()(struct tty_struct *tty)``
64  *
65  *	This routine is called under the tty lock when a particular @tty device
66  *	is closed for the last time. It executes before the @tty resources
67  *	are freed so may execute while another function holds a @tty kref.
68  *
69  * @cleanup: ``void ()(struct tty_struct *tty)``
70  *
71  *	This routine is called asynchronously when a particular @tty device
72  *	is closed for the last time freeing up the resources. This is
73  *	actually the second part of shutdown for routines that might sleep.
74  *
75  * @write: ``int ()(struct tty_struct *tty, const unsigned char *buf,
76  *		    int count)``
77  *
78  *	This routine is called by the kernel to write a series (@count) of
79  *	characters (@buf) to the @tty device. The characters may come from
80  *	user space or kernel space.  This routine will return the
81  *	number of characters actually accepted for writing.
82  *
83  *	May occur in parallel in special cases. Because this includes panic
84  *	paths drivers generally shouldn't try and do clever locking here.
85  *
86  *	Optional: Required for writable devices. May not sleep.
87  *
88  * @put_char: ``int ()(struct tty_struct *tty, unsigned char ch)``
89  *
90  *	This routine is called by the kernel to write a single character @ch to
91  *	the @tty device. If the kernel uses this routine, it must call the
92  *	@flush_chars() routine (if defined) when it is done stuffing characters
93  *	into the driver. If there is no room in the queue, the character is
94  *	ignored.
95  *
96  *	Optional: Kernel will use the @write method if not provided. Do not
97  *	call this function directly, call tty_put_char().
98  *
99  * @flush_chars: ``void ()(struct tty_struct *tty)``
100  *
101  *	This routine is called by the kernel after it has written a
102  *	series of characters to the tty device using @put_char().
103  *
104  *	Optional. Do not call this function directly, call
105  *	tty_driver_flush_chars().
106  *
107  * @write_room: ``unsigned int ()(struct tty_struct *tty)``
108  *
109  *	This routine returns the numbers of characters the @tty driver
110  *	will accept for queuing to be written.  This number is subject
111  *	to change as output buffers get emptied, or if the output flow
112  *	control is acted.
113  *
114  *	The ldisc is responsible for being intelligent about multi-threading of
115  *	write_room/write calls
116  *
117  *	Required if @write method is provided else not needed. Do not call this
118  *	function directly, call tty_write_room()
119  *
120  * @chars_in_buffer: ``unsigned int ()(struct tty_struct *tty)``
121  *
122  *	This routine returns the number of characters in the device private
123  *	output queue. Used in tty_wait_until_sent() and for poll()
124  *	implementation.
125  *
126  *	Optional: if not provided, it is assumed there is no queue on the
127  *	device. Do not call this function directly, call tty_chars_in_buffer().
128  *
129  * @ioctl: ``int ()(struct tty_struct *tty, unsigned int cmd,
130  *		    unsigned long arg)``
131  *
132  *	This routine allows the @tty driver to implement device-specific
133  *	ioctls. If the ioctl number passed in @cmd is not recognized by the
134  *	driver, it should return %ENOIOCTLCMD.
135  *
136  *	Optional.
137  *
138  * @compat_ioctl: ``long ()(struct tty_struct *tty, unsigned int cmd,
139  *			  unsigned long arg)``
140  *
141  *	Implement ioctl processing for 32 bit process on 64 bit system.
142  *
143  *	Optional.
144  *
145  * @set_termios: ``void ()(struct tty_struct *tty, const struct ktermios *old)``
146  *
147  *	This routine allows the @tty driver to be notified when device's
148  *	termios settings have changed. New settings are in @tty->termios.
149  *	Previous settings are passed in the @old argument.
150  *
151  *	The API is defined such that the driver should return the actual modes
152  *	selected. This means that the driver is responsible for modifying any
153  *	bits in @tty->termios it cannot fulfill to indicate the actual modes
154  *	being used.
155  *
156  *	Optional. Called under the @tty->termios_rwsem. May sleep.
157  *
158  * @set_ldisc: ``void ()(struct tty_struct *tty)``
159  *
160  *	This routine allows the @tty driver to be notified when the device's
161  *	line discipline is being changed. At the point this is done the
162  *	discipline is not yet usable.
163  *
164  *	Optional. Called under the @tty->ldisc_sem and @tty->termios_rwsem.
165  *
166  * @throttle: ``void ()(struct tty_struct *tty)``
167  *
168  *	This routine notifies the @tty driver that input buffers for the line
169  *	discipline are close to full, and it should somehow signal that no more
170  *	characters should be sent to the @tty.
171  *
172  *	Serialization including with @unthrottle() is the job of the ldisc
173  *	layer.
174  *
175  *	Optional: Always invoke via tty_throttle_safe(). Called under the
176  *	@tty->termios_rwsem.
177  *
178  * @unthrottle: ``void ()(struct tty_struct *tty)``
179  *
180  *	This routine notifies the @tty driver that it should signal that
181  *	characters can now be sent to the @tty without fear of overrunning the
182  *	input buffers of the line disciplines.
183  *
184  *	Optional. Always invoke via tty_unthrottle(). Called under the
185  *	@tty->termios_rwsem.
186  *
187  * @stop: ``void ()(struct tty_struct *tty)``
188  *
189  *	This routine notifies the @tty driver that it should stop outputting
190  *	characters to the tty device.
191  *
192  *	Called with @tty->flow.lock held. Serialized with @start() method.
193  *
194  *	Optional. Always invoke via stop_tty().
195  *
196  * @start: ``void ()(struct tty_struct *tty)``
197  *
198  *	This routine notifies the @tty driver that it resumed sending
199  *	characters to the @tty device.
200  *
201  *	Called with @tty->flow.lock held. Serialized with stop() method.
202  *
203  *	Optional. Always invoke via start_tty().
204  *
205  * @hangup: ``void ()(struct tty_struct *tty)``
206  *
207  *	This routine notifies the @tty driver that it should hang up the @tty
208  *	device.
209  *
210  *	Optional. Called with tty lock held.
211  *
212  * @break_ctl: ``int ()(struct tty_struct *tty, int state)``
213  *
214  *	This optional routine requests the @tty driver to turn on or off BREAK
215  *	status on the RS-232 port. If @state is -1, then the BREAK status
216  *	should be turned on; if @state is 0, then BREAK should be turned off.
217  *
218  *	If this routine is implemented, the high-level tty driver will handle
219  *	the following ioctls: %TCSBRK, %TCSBRKP, %TIOCSBRK, %TIOCCBRK.
220  *
221  *	If the driver sets %TTY_DRIVER_HARDWARE_BREAK in tty_alloc_driver(),
222  *	then the interface will also be called with actual times and the
223  *	hardware is expected to do the delay work itself. 0 and -1 are still
224  *	used for on/off.
225  *
226  *	Optional: Required for %TCSBRK/%BRKP/etc. handling. May sleep.
227  *
228  * @flush_buffer: ``void ()(struct tty_struct *tty)``
229  *
230  *	This routine discards device private output buffer. Invoked on close,
231  *	hangup, to implement %TCOFLUSH ioctl and similar.
232  *
233  *	Optional: if not provided, it is assumed there is no queue on the
234  *	device. Do not call this function directly, call
235  *	tty_driver_flush_buffer().
236  *
237  * @wait_until_sent: ``void ()(struct tty_struct *tty, int timeout)``
238  *
239  *	This routine waits until the device has written out all of the
240  *	characters in its transmitter FIFO. Or until @timeout (in jiffies) is
241  *	reached.
242  *
243  *	Optional: If not provided, the device is assumed to have no FIFO.
244  *	Usually correct to invoke via tty_wait_until_sent(). May sleep.
245  *
246  * @send_xchar: ``void ()(struct tty_struct *tty, char ch)``
247  *
248  *	This routine is used to send a high-priority XON/XOFF character (@ch)
249  *	to the @tty device.
250  *
251  *	Optional: If not provided, then the @write method is called under
252  *	the @tty->atomic_write_lock to keep it serialized with the ldisc.
253  *
254  * @tiocmget: ``int ()(struct tty_struct *tty)``
255  *
256  *	This routine is used to obtain the modem status bits from the @tty
257  *	driver.
258  *
259  *	Optional: If not provided, then %ENOTTY is returned from the %TIOCMGET
260  *	ioctl. Do not call this function directly, call tty_tiocmget().
261  *
262  * @tiocmset: ``int ()(struct tty_struct *tty,
263  *		       unsigned int set, unsigned int clear)``
264  *
265  *	This routine is used to set the modem status bits to the @tty driver.
266  *	First, @clear bits should be cleared, then @set bits set.
267  *
268  *	Optional: If not provided, then %ENOTTY is returned from the %TIOCMSET
269  *	ioctl. Do not call this function directly, call tty_tiocmset().
270  *
271  * @resize: ``int ()(struct tty_struct *tty, struct winsize *ws)``
272  *
273  *	Called when a termios request is issued which changes the requested
274  *	terminal geometry to @ws.
275  *
276  *	Optional: the default action is to update the termios structure
277  *	without error. This is usually the correct behaviour. Drivers should
278  *	not force errors here if they are not resizable objects (e.g. a serial
279  *	line). See tty_do_resize() if you need to wrap the standard method
280  *	in your own logic -- the usual case.
281  *
282  * @get_icount: ``int ()(struct tty_struct *tty,
283  *			 struct serial_icounter *icount)``
284  *
285  *	Called when the @tty device receives a %TIOCGICOUNT ioctl. Passed a
286  *	kernel structure @icount to complete.
287  *
288  *	Optional: called only if provided, otherwise %ENOTTY will be returned.
289  *
290  * @get_serial: ``int ()(struct tty_struct *tty, struct serial_struct *p)``
291  *
292  *	Called when the @tty device receives a %TIOCGSERIAL ioctl. Passed a
293  *	kernel structure @p (&struct serial_struct) to complete.
294  *
295  *	Optional: called only if provided, otherwise %ENOTTY will be returned.
296  *	Do not call this function directly, call tty_tiocgserial().
297  *
298  * @set_serial: ``int ()(struct tty_struct *tty, struct serial_struct *p)``
299  *
300  *	Called when the @tty device receives a %TIOCSSERIAL ioctl. Passed a
301  *	kernel structure @p (&struct serial_struct) to set the values from.
302  *
303  *	Optional: called only if provided, otherwise %ENOTTY will be returned.
304  *	Do not call this function directly, call tty_tiocsserial().
305  *
306  * @show_fdinfo: ``void ()(struct tty_struct *tty, struct seq_file *m)``
307  *
308  *	Called when the @tty device file descriptor receives a fdinfo request
309  *	from VFS (to show in /proc/<pid>/fdinfo/). @m should be filled with
310  *	information.
311  *
312  *	Optional: called only if provided, otherwise nothing is written to @m.
313  *	Do not call this function directly, call tty_show_fdinfo().
314  *
315  * @poll_init: ``int ()(struct tty_driver *driver, int line, char *options)``
316  *
317  *	kgdboc support (Documentation/dev-tools/kgdb.rst). This routine is
318  *	called to initialize the HW for later use by calling @poll_get_char or
319  *	@poll_put_char.
320  *
321  *	Optional: called only if provided, otherwise skipped as a non-polling
322  *	driver.
323  *
324  * @poll_get_char: ``int ()(struct tty_driver *driver, int line)``
325  *
326  *	kgdboc support (see @poll_init). @driver should read a character from a
327  *	tty identified by @line and return it.
328  *
329  *	Optional: called only if @poll_init provided.
330  *
331  * @poll_put_char: ``void ()(struct tty_driver *driver, int line, char ch)``
332  *
333  *	kgdboc support (see @poll_init). @driver should write character @ch to
334  *	a tty identified by @line.
335  *
336  *	Optional: called only if @poll_init provided.
337  *
338  * @proc_show: ``int ()(struct seq_file *m, void *driver)``
339  *
340  *	Driver @driver (cast to &struct tty_driver) can show additional info in
341  *	/proc/tty/driver/<driver_name>. It is enough to fill in the information
342  *	into @m.
343  *
344  *	Optional: called only if provided, otherwise no /proc entry created.
345  *
346  * This structure defines the interface between the low-level tty driver and
347  * the tty routines. These routines can be defined. Unless noted otherwise,
348  * they are optional, and can be filled in with a %NULL pointer.
349  */
350 struct tty_operations {
351 	struct tty_struct * (*lookup)(struct tty_driver *driver,
352 			struct file *filp, int idx);
353 	int  (*install)(struct tty_driver *driver, struct tty_struct *tty);
354 	void (*remove)(struct tty_driver *driver, struct tty_struct *tty);
355 	int  (*open)(struct tty_struct * tty, struct file * filp);
356 	void (*close)(struct tty_struct * tty, struct file * filp);
357 	void (*shutdown)(struct tty_struct *tty);
358 	void (*cleanup)(struct tty_struct *tty);
359 	int  (*write)(struct tty_struct * tty,
360 		      const unsigned char *buf, int count);
361 	int  (*put_char)(struct tty_struct *tty, unsigned char ch);
362 	void (*flush_chars)(struct tty_struct *tty);
363 	unsigned int (*write_room)(struct tty_struct *tty);
364 	unsigned int (*chars_in_buffer)(struct tty_struct *tty);
365 	int  (*ioctl)(struct tty_struct *tty,
366 		    unsigned int cmd, unsigned long arg);
367 	long (*compat_ioctl)(struct tty_struct *tty,
368 			     unsigned int cmd, unsigned long arg);
369 	void (*set_termios)(struct tty_struct *tty, const struct ktermios *old);
370 	void (*throttle)(struct tty_struct * tty);
371 	void (*unthrottle)(struct tty_struct * tty);
372 	void (*stop)(struct tty_struct *tty);
373 	void (*start)(struct tty_struct *tty);
374 	void (*hangup)(struct tty_struct *tty);
375 	int (*break_ctl)(struct tty_struct *tty, int state);
376 	void (*flush_buffer)(struct tty_struct *tty);
377 	void (*set_ldisc)(struct tty_struct *tty);
378 	void (*wait_until_sent)(struct tty_struct *tty, int timeout);
379 	void (*send_xchar)(struct tty_struct *tty, char ch);
380 	int (*tiocmget)(struct tty_struct *tty);
381 	int (*tiocmset)(struct tty_struct *tty,
382 			unsigned int set, unsigned int clear);
383 	int (*resize)(struct tty_struct *tty, struct winsize *ws);
384 	int (*get_icount)(struct tty_struct *tty,
385 				struct serial_icounter_struct *icount);
386 	int  (*get_serial)(struct tty_struct *tty, struct serial_struct *p);
387 	int  (*set_serial)(struct tty_struct *tty, struct serial_struct *p);
388 	void (*show_fdinfo)(struct tty_struct *tty, struct seq_file *m);
389 #ifdef CONFIG_CONSOLE_POLL
390 	int (*poll_init)(struct tty_driver *driver, int line, char *options);
391 	int (*poll_get_char)(struct tty_driver *driver, int line);
392 	void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
393 #endif
394 	int (*proc_show)(struct seq_file *m, void *driver);
395 } __randomize_layout;
396 
397 /**
398  * struct tty_driver -- driver for TTY devices
399  *
400  * @kref: reference counting. Reaching zero frees all the internals and the
401  *	  driver.
402  * @cdevs: allocated/registered character /dev devices
403  * @owner: modules owning this driver. Used drivers cannot be rmmod'ed.
404  *	   Automatically set by tty_alloc_driver().
405  * @driver_name: name of the driver used in /proc/tty
406  * @name: used for constructing /dev node name
407  * @name_base: used as a number base for constructing /dev node name
408  * @major: major /dev device number (zero for autoassignment)
409  * @minor_start: the first minor /dev device number
410  * @num: number of devices allocated
411  * @type: type of tty driver (%TTY_DRIVER_TYPE_)
412  * @subtype: subtype of tty driver (%SYSTEM_TYPE_, %PTY_TYPE_, %SERIAL_TYPE_)
413  * @init_termios: termios to set to each tty initially (e.g. %tty_std_termios)
414  * @flags: tty driver flags (%TTY_DRIVER_)
415  * @proc_entry: proc fs entry, used internally
416  * @other: driver of the linked tty; only used for the PTY driver
417  * @ttys: array of active &struct tty_struct, set by tty_standard_install()
418  * @ports: array of &struct tty_port; can be set during initialization by
419  *	   tty_port_link_device() and similar
420  * @termios: storage for termios at each TTY close for the next open
421  * @driver_state: pointer to driver's arbitrary data
422  * @ops: driver hooks for TTYs. Set them using tty_set_operations(). Use &struct
423  *	 tty_port helpers in them as much as possible.
424  * @tty_drivers: used internally to link tty_drivers together
425  *
426  * The usual handling of &struct tty_driver is to allocate it by
427  * tty_alloc_driver(), set up all the necessary members, and register it by
428  * tty_register_driver(). At last, the driver is torn down by calling
429  * tty_unregister_driver() followed by tty_driver_kref_put().
430  *
431  * The fields required to be set before calling tty_register_driver() include
432  * @driver_name, @name, @type, @subtype, @init_termios, and @ops.
433  */
434 struct tty_driver {
435 	struct kref kref;
436 	struct cdev **cdevs;
437 	struct module	*owner;
438 	const char	*driver_name;
439 	const char	*name;
440 	int	name_base;
441 	int	major;
442 	int	minor_start;
443 	unsigned int	num;
444 	short	type;
445 	short	subtype;
446 	struct ktermios init_termios;
447 	unsigned long	flags;
448 	struct proc_dir_entry *proc_entry;
449 	struct tty_driver *other;
450 
451 	/*
452 	 * Pointer to the tty data structures
453 	 */
454 	struct tty_struct **ttys;
455 	struct tty_port **ports;
456 	struct ktermios **termios;
457 	void *driver_state;
458 
459 	/*
460 	 * Driver methods
461 	 */
462 
463 	const struct tty_operations *ops;
464 	struct list_head tty_drivers;
465 } __randomize_layout;
466 
467 extern struct list_head tty_drivers;
468 
469 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
470 		unsigned long flags);
471 struct tty_driver *tty_find_polling_driver(char *name, int *line);
472 
473 void tty_driver_kref_put(struct tty_driver *driver);
474 
475 /* Use TTY_DRIVER_* flags below */
476 #define tty_alloc_driver(lines, flags) \
477 		__tty_alloc_driver(lines, THIS_MODULE, flags)
478 
tty_driver_kref_get(struct tty_driver * d)479 static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
480 {
481 	kref_get(&d->kref);
482 	return d;
483 }
484 
tty_set_operations(struct tty_driver * driver,const struct tty_operations * op)485 static inline void tty_set_operations(struct tty_driver *driver,
486 		const struct tty_operations *op)
487 {
488 	driver->ops = op;
489 }
490 
491 /**
492  * DOC: TTY Driver Flags
493  *
494  * TTY_DRIVER_RESET_TERMIOS
495  *	Requests the tty layer to reset the termios setting when the last
496  *	process has closed the device. Used for PTYs, in particular.
497  *
498  * TTY_DRIVER_REAL_RAW
499  *	Indicates that the driver will guarantee not to set any special
500  *	character handling flags if this is set for the tty:
501  *
502  *	``(IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR || !INPCK)``
503  *
504  *	That is, if there is no reason for the driver to
505  *	send notifications of parity and break characters up to the line
506  *	driver, it won't do so.  This allows the line driver to optimize for
507  *	this case if this flag is set.  (Note that there is also a promise, if
508  *	the above case is true, not to signal overruns, either.)
509  *
510  * TTY_DRIVER_DYNAMIC_DEV
511  *	The individual tty devices need to be registered with a call to
512  *	tty_register_device() when the device is found in the system and
513  *	unregistered with a call to tty_unregister_device() so the devices will
514  *	be show up properly in sysfs.  If not set, all &tty_driver.num entries
515  *	will be created by the tty core in sysfs when tty_register_driver() is
516  *	called.  This is to be used by drivers that have tty devices that can
517  *	appear and disappear while the main tty driver is registered with the
518  *	tty core.
519  *
520  * TTY_DRIVER_DEVPTS_MEM
521  *	Don't use the standard arrays (&tty_driver.ttys and
522  *	&tty_driver.termios), instead use dynamic memory keyed through the
523  *	devpts filesystem. This is only applicable to the PTY driver.
524  *
525  * TTY_DRIVER_HARDWARE_BREAK
526  *	Hardware handles break signals. Pass the requested timeout to the
527  *	&tty_operations.break_ctl instead of using a simple on/off interface.
528  *
529  * TTY_DRIVER_DYNAMIC_ALLOC
530  *	Do not allocate structures which are needed per line for this driver
531  *	(&tty_driver.ports) as it would waste memory. The driver will take
532  *	care. This is only applicable to the PTY driver.
533  *
534  * TTY_DRIVER_UNNUMBERED_NODE
535  *	Do not create numbered ``/dev`` nodes. For example, create
536  *	``/dev/ttyprintk`` and not ``/dev/ttyprintk0``. Applicable only when a
537  *	driver for a single tty device is being allocated.
538  */
539 #define TTY_DRIVER_INSTALLED		0x0001
540 #define TTY_DRIVER_RESET_TERMIOS	0x0002
541 #define TTY_DRIVER_REAL_RAW		0x0004
542 #define TTY_DRIVER_DYNAMIC_DEV		0x0008
543 #define TTY_DRIVER_DEVPTS_MEM		0x0010
544 #define TTY_DRIVER_HARDWARE_BREAK	0x0020
545 #define TTY_DRIVER_DYNAMIC_ALLOC	0x0040
546 #define TTY_DRIVER_UNNUMBERED_NODE	0x0080
547 
548 /* tty driver types */
549 #define TTY_DRIVER_TYPE_SYSTEM		0x0001
550 #define TTY_DRIVER_TYPE_CONSOLE		0x0002
551 #define TTY_DRIVER_TYPE_SERIAL		0x0003
552 #define TTY_DRIVER_TYPE_PTY		0x0004
553 #define TTY_DRIVER_TYPE_SCC		0x0005	/* scc driver */
554 #define TTY_DRIVER_TYPE_SYSCONS		0x0006
555 
556 /* system subtypes (magic, used by tty_io.c) */
557 #define SYSTEM_TYPE_TTY			0x0001
558 #define SYSTEM_TYPE_CONSOLE		0x0002
559 #define SYSTEM_TYPE_SYSCONS		0x0003
560 #define SYSTEM_TYPE_SYSPTMX		0x0004
561 
562 /* pty subtypes (magic, used by tty_io.c) */
563 #define PTY_TYPE_MASTER			0x0001
564 #define PTY_TYPE_SLAVE			0x0002
565 
566 /* serial subtype definitions */
567 #define SERIAL_TYPE_NORMAL	1
568 
569 int tty_register_driver(struct tty_driver *driver);
570 void tty_unregister_driver(struct tty_driver *driver);
571 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
572 		struct device *dev);
573 struct device *tty_register_device_attr(struct tty_driver *driver,
574 		unsigned index, struct device *device, void *drvdata,
575 		const struct attribute_group **attr_grp);
576 void tty_unregister_device(struct tty_driver *driver, unsigned index);
577 
578 #ifdef CONFIG_PROC_FS
579 void proc_tty_register_driver(struct tty_driver *);
580 void proc_tty_unregister_driver(struct tty_driver *);
581 #else
proc_tty_register_driver(struct tty_driver * d)582 static inline void proc_tty_register_driver(struct tty_driver *d) {}
proc_tty_unregister_driver(struct tty_driver * d)583 static inline void proc_tty_unregister_driver(struct tty_driver *d) {}
584 #endif
585 
586 #endif /* #ifdef _LINUX_TTY_DRIVER_H */
587