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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 #include <linux/android_kabi.h>
14 
15 struct tty_struct;
16 struct tty_driver;
17 struct serial_icounter_struct;
18 struct serial_struct;
19 
20 /**
21  * struct tty_operations -- interface between driver and tty
22  *
23  * @lookup: ``struct tty_struct *()(struct tty_driver *self, struct file *,
24  *				    int idx)``
25  *
26  *	Return the tty device corresponding to @idx, %NULL if there is not
27  *	one currently in use and an %ERR_PTR value on error. Called under
28  *	%tty_mutex (for now!)
29  *
30  *	Optional method. Default behaviour is to use the @self->ttys array.
31  *
32  * @install: ``int ()(struct tty_driver *self, struct tty_struct *tty)``
33  *
34  *	Install a new @tty into the @self's internal tables. Used in
35  *	conjunction with @lookup and @remove methods.
36  *
37  *	Optional method. Default behaviour is to use the @self->ttys array.
38  *
39  * @remove: ``void ()(struct tty_driver *self, struct tty_struct *tty)``
40  *
41  *	Remove a closed @tty from the @self's internal tables. Used in
42  *	conjunction with @lookup and @remove methods.
43  *
44  *	Optional method. Default behaviour is to use the @self->ttys array.
45  *
46  * @open: ``int ()(struct tty_struct *tty, struct file *)``
47  *
48  *	This routine is called when a particular @tty device is opened. This
49  *	routine is mandatory; if this routine is not filled in, the attempted
50  *	open will fail with %ENODEV.
51  *
52  *	Required method. Called with tty lock held. May sleep.
53  *
54  * @close: ``void ()(struct tty_struct *tty, struct file *)``
55  *
56  *	This routine is called when a particular @tty device is closed. At the
57  *	point of return from this call the driver must make no further ldisc
58  *	calls of any kind.
59  *
60  *	Remark: called even if the corresponding @open() failed.
61  *
62  *	Required method. Called with tty lock held. May sleep.
63  *
64  * @shutdown: ``void ()(struct tty_struct *tty)``
65  *
66  *	This routine is called under the tty lock when a particular @tty device
67  *	is closed for the last time. It executes before the @tty resources
68  *	are freed so may execute while another function holds a @tty kref.
69  *
70  * @cleanup: ``void ()(struct tty_struct *tty)``
71  *
72  *	This routine is called asynchronously when a particular @tty device
73  *	is closed for the last time freeing up the resources. This is
74  *	actually the second part of shutdown for routines that might sleep.
75  *
76  * @write: ``int ()(struct tty_struct *tty, const unsigned char *buf,
77  *		    int count)``
78  *
79  *	This routine is called by the kernel to write a series (@count) of
80  *	characters (@buf) to the @tty device. The characters may come from
81  *	user space or kernel space.  This routine will return the
82  *	number of characters actually accepted for writing.
83  *
84  *	May occur in parallel in special cases. Because this includes panic
85  *	paths drivers generally shouldn't try and do clever locking here.
86  *
87  *	Optional: Required for writable devices. May not sleep.
88  *
89  * @put_char: ``int ()(struct tty_struct *tty, unsigned char ch)``
90  *
91  *	This routine is called by the kernel to write a single character @ch to
92  *	the @tty device. If the kernel uses this routine, it must call the
93  *	@flush_chars() routine (if defined) when it is done stuffing characters
94  *	into the driver. If there is no room in the queue, the character is
95  *	ignored.
96  *
97  *	Optional: Kernel will use the @write method if not provided. Do not
98  *	call this function directly, call tty_put_char().
99  *
100  * @flush_chars: ``void ()(struct tty_struct *tty)``
101  *
102  *	This routine is called by the kernel after it has written a
103  *	series of characters to the tty device using @put_char().
104  *
105  *	Optional. Do not call this function directly, call
106  *	tty_driver_flush_chars().
107  *
108  * @write_room: ``unsigned int ()(struct tty_struct *tty)``
109  *
110  *	This routine returns the numbers of characters the @tty driver
111  *	will accept for queuing to be written.  This number is subject
112  *	to change as output buffers get emptied, or if the output flow
113  *	control is acted.
114  *
115  *	The ldisc is responsible for being intelligent about multi-threading of
116  *	write_room/write calls
117  *
118  *	Required if @write method is provided else not needed. Do not call this
119  *	function directly, call tty_write_room()
120  *
121  * @chars_in_buffer: ``unsigned int ()(struct tty_struct *tty)``
122  *
123  *	This routine returns the number of characters in the device private
124  *	output queue. Used in tty_wait_until_sent() and for poll()
125  *	implementation.
126  *
127  *	Optional: if not provided, it is assumed there is no queue on the
128  *	device. Do not call this function directly, call tty_chars_in_buffer().
129  *
130  * @ioctl: ``int ()(struct tty_struct *tty, unsigned int cmd,
131  *		    unsigned long arg)``
132  *
133  *	This routine allows the @tty driver to implement device-specific
134  *	ioctls. If the ioctl number passed in @cmd is not recognized by the
135  *	driver, it should return %ENOIOCTLCMD.
136  *
137  *	Optional.
138  *
139  * @compat_ioctl: ``long ()(struct tty_struct *tty, unsigned int cmd,
140  *			  unsigned long arg)``
141  *
142  *	Implement ioctl processing for 32 bit process on 64 bit system.
143  *
144  *	Optional.
145  *
146  * @set_termios: ``void ()(struct tty_struct *tty, const struct ktermios *old)``
147  *
148  *	This routine allows the @tty driver to be notified when device's
149  *	termios settings have changed. New settings are in @tty->termios.
150  *	Previous settings are passed in the @old argument.
151  *
152  *	The API is defined such that the driver should return the actual modes
153  *	selected. This means that the driver is responsible for modifying any
154  *	bits in @tty->termios it cannot fulfill to indicate the actual modes
155  *	being used.
156  *
157  *	Optional. Called under the @tty->termios_rwsem. May sleep.
158  *
159  * @set_ldisc: ``void ()(struct tty_struct *tty)``
160  *
161  *	This routine allows the @tty driver to be notified when the device's
162  *	line discipline is being changed. At the point this is done the
163  *	discipline is not yet usable.
164  *
165  *	Optional. Called under the @tty->ldisc_sem and @tty->termios_rwsem.
166  *
167  * @throttle: ``void ()(struct tty_struct *tty)``
168  *
169  *	This routine notifies the @tty driver that input buffers for the line
170  *	discipline are close to full, and it should somehow signal that no more
171  *	characters should be sent to the @tty.
172  *
173  *	Serialization including with @unthrottle() is the job of the ldisc
174  *	layer.
175  *
176  *	Optional: Always invoke via tty_throttle_safe(). Called under the
177  *	@tty->termios_rwsem.
178  *
179  * @unthrottle: ``void ()(struct tty_struct *tty)``
180  *
181  *	This routine notifies the @tty driver that it should signal that
182  *	characters can now be sent to the @tty without fear of overrunning the
183  *	input buffers of the line disciplines.
184  *
185  *	Optional. Always invoke via tty_unthrottle(). Called under the
186  *	@tty->termios_rwsem.
187  *
188  * @stop: ``void ()(struct tty_struct *tty)``
189  *
190  *	This routine notifies the @tty driver that it should stop outputting
191  *	characters to the tty device.
192  *
193  *	Called with @tty->flow.lock held. Serialized with @start() method.
194  *
195  *	Optional. Always invoke via stop_tty().
196  *
197  * @start: ``void ()(struct tty_struct *tty)``
198  *
199  *	This routine notifies the @tty driver that it resumed sending
200  *	characters to the @tty device.
201  *
202  *	Called with @tty->flow.lock held. Serialized with stop() method.
203  *
204  *	Optional. Always invoke via start_tty().
205  *
206  * @hangup: ``void ()(struct tty_struct *tty)``
207  *
208  *	This routine notifies the @tty driver that it should hang up the @tty
209  *	device.
210  *
211  *	Optional. Called with tty lock held.
212  *
213  * @break_ctl: ``int ()(struct tty_struct *tty, int state)``
214  *
215  *	This optional routine requests the @tty driver to turn on or off BREAK
216  *	status on the RS-232 port. If @state is -1, then the BREAK status
217  *	should be turned on; if @state is 0, then BREAK should be turned off.
218  *
219  *	If this routine is implemented, the high-level tty driver will handle
220  *	the following ioctls: %TCSBRK, %TCSBRKP, %TIOCSBRK, %TIOCCBRK.
221  *
222  *	If the driver sets %TTY_DRIVER_HARDWARE_BREAK in tty_alloc_driver(),
223  *	then the interface will also be called with actual times and the
224  *	hardware is expected to do the delay work itself. 0 and -1 are still
225  *	used for on/off.
226  *
227  *	Optional: Required for %TCSBRK/%BRKP/etc. handling. May sleep.
228  *
229  * @flush_buffer: ``void ()(struct tty_struct *tty)``
230  *
231  *	This routine discards device private output buffer. Invoked on close,
232  *	hangup, to implement %TCOFLUSH ioctl and similar.
233  *
234  *	Optional: if not provided, it is assumed there is no queue on the
235  *	device. Do not call this function directly, call
236  *	tty_driver_flush_buffer().
237  *
238  * @wait_until_sent: ``void ()(struct tty_struct *tty, int timeout)``
239  *
240  *	This routine waits until the device has written out all of the
241  *	characters in its transmitter FIFO. Or until @timeout (in jiffies) is
242  *	reached.
243  *
244  *	Optional: If not provided, the device is assumed to have no FIFO.
245  *	Usually correct to invoke via tty_wait_until_sent(). May sleep.
246  *
247  * @send_xchar: ``void ()(struct tty_struct *tty, char ch)``
248  *
249  *	This routine is used to send a high-priority XON/XOFF character (@ch)
250  *	to the @tty device.
251  *
252  *	Optional: If not provided, then the @write method is called under
253  *	the @tty->atomic_write_lock to keep it serialized with the ldisc.
254  *
255  * @tiocmget: ``int ()(struct tty_struct *tty)``
256  *
257  *	This routine is used to obtain the modem status bits from the @tty
258  *	driver.
259  *
260  *	Optional: If not provided, then %ENOTTY is returned from the %TIOCMGET
261  *	ioctl. Do not call this function directly, call tty_tiocmget().
262  *
263  * @tiocmset: ``int ()(struct tty_struct *tty,
264  *		       unsigned int set, unsigned int clear)``
265  *
266  *	This routine is used to set the modem status bits to the @tty driver.
267  *	First, @clear bits should be cleared, then @set bits set.
268  *
269  *	Optional: If not provided, then %ENOTTY is returned from the %TIOCMSET
270  *	ioctl. Do not call this function directly, call tty_tiocmset().
271  *
272  * @resize: ``int ()(struct tty_struct *tty, struct winsize *ws)``
273  *
274  *	Called when a termios request is issued which changes the requested
275  *	terminal geometry to @ws.
276  *
277  *	Optional: the default action is to update the termios structure
278  *	without error. This is usually the correct behaviour. Drivers should
279  *	not force errors here if they are not resizable objects (e.g. a serial
280  *	line). See tty_do_resize() if you need to wrap the standard method
281  *	in your own logic -- the usual case.
282  *
283  * @get_icount: ``int ()(struct tty_struct *tty,
284  *			 struct serial_icounter *icount)``
285  *
286  *	Called when the @tty device receives a %TIOCGICOUNT ioctl. Passed a
287  *	kernel structure @icount to complete.
288  *
289  *	Optional: called only if provided, otherwise %ENOTTY will be returned.
290  *
291  * @get_serial: ``int ()(struct tty_struct *tty, struct serial_struct *p)``
292  *
293  *	Called when the @tty device receives a %TIOCGSERIAL ioctl. Passed a
294  *	kernel structure @p (&struct serial_struct) to complete.
295  *
296  *	Optional: called only if provided, otherwise %ENOTTY will be returned.
297  *	Do not call this function directly, call tty_tiocgserial().
298  *
299  * @set_serial: ``int ()(struct tty_struct *tty, struct serial_struct *p)``
300  *
301  *	Called when the @tty device receives a %TIOCSSERIAL ioctl. Passed a
302  *	kernel structure @p (&struct serial_struct) to set the values from.
303  *
304  *	Optional: called only if provided, otherwise %ENOTTY will be returned.
305  *	Do not call this function directly, call tty_tiocsserial().
306  *
307  * @show_fdinfo: ``void ()(struct tty_struct *tty, struct seq_file *m)``
308  *
309  *	Called when the @tty device file descriptor receives a fdinfo request
310  *	from VFS (to show in /proc/<pid>/fdinfo/). @m should be filled with
311  *	information.
312  *
313  *	Optional: called only if provided, otherwise nothing is written to @m.
314  *	Do not call this function directly, call tty_show_fdinfo().
315  *
316  * @poll_init: ``int ()(struct tty_driver *driver, int line, char *options)``
317  *
318  *	kgdboc support (Documentation/dev-tools/kgdb.rst). This routine is
319  *	called to initialize the HW for later use by calling @poll_get_char or
320  *	@poll_put_char.
321  *
322  *	Optional: called only if provided, otherwise skipped as a non-polling
323  *	driver.
324  *
325  * @poll_get_char: ``int ()(struct tty_driver *driver, int line)``
326  *
327  *	kgdboc support (see @poll_init). @driver should read a character from a
328  *	tty identified by @line and return it.
329  *
330  *	Optional: called only if @poll_init provided.
331  *
332  * @poll_put_char: ``void ()(struct tty_driver *driver, int line, char ch)``
333  *
334  *	kgdboc support (see @poll_init). @driver should write character @ch to
335  *	a tty identified by @line.
336  *
337  *	Optional: called only if @poll_init provided.
338  *
339  * @proc_show: ``int ()(struct seq_file *m, void *driver)``
340  *
341  *	Driver @driver (cast to &struct tty_driver) can show additional info in
342  *	/proc/tty/driver/<driver_name>. It is enough to fill in the information
343  *	into @m.
344  *
345  *	Optional: called only if provided, otherwise no /proc entry created.
346  *
347  * This structure defines the interface between the low-level tty driver and
348  * the tty routines. These routines can be defined. Unless noted otherwise,
349  * they are optional, and can be filled in with a %NULL pointer.
350  */
351 struct tty_operations {
352 	struct tty_struct * (*lookup)(struct tty_driver *driver,
353 			struct file *filp, int idx);
354 	int  (*install)(struct tty_driver *driver, struct tty_struct *tty);
355 	void (*remove)(struct tty_driver *driver, struct tty_struct *tty);
356 	int  (*open)(struct tty_struct * tty, struct file * filp);
357 	void (*close)(struct tty_struct * tty, struct file * filp);
358 	void (*shutdown)(struct tty_struct *tty);
359 	void (*cleanup)(struct tty_struct *tty);
360 	int  (*write)(struct tty_struct * tty,
361 		      const unsigned char *buf, int count);
362 	int  (*put_char)(struct tty_struct *tty, unsigned char ch);
363 	void (*flush_chars)(struct tty_struct *tty);
364 	unsigned int (*write_room)(struct tty_struct *tty);
365 	unsigned int (*chars_in_buffer)(struct tty_struct *tty);
366 	int  (*ioctl)(struct tty_struct *tty,
367 		    unsigned int cmd, unsigned long arg);
368 	long (*compat_ioctl)(struct tty_struct *tty,
369 			     unsigned int cmd, unsigned long arg);
370 	void (*set_termios)(struct tty_struct *tty, const struct ktermios *old);
371 	void (*throttle)(struct tty_struct * tty);
372 	void (*unthrottle)(struct tty_struct * tty);
373 	void (*stop)(struct tty_struct *tty);
374 	void (*start)(struct tty_struct *tty);
375 	void (*hangup)(struct tty_struct *tty);
376 	int (*break_ctl)(struct tty_struct *tty, int state);
377 	void (*flush_buffer)(struct tty_struct *tty);
378 	void (*set_ldisc)(struct tty_struct *tty);
379 	void (*wait_until_sent)(struct tty_struct *tty, int timeout);
380 	void (*send_xchar)(struct tty_struct *tty, char ch);
381 	int (*tiocmget)(struct tty_struct *tty);
382 	int (*tiocmset)(struct tty_struct *tty,
383 			unsigned int set, unsigned int clear);
384 	int (*resize)(struct tty_struct *tty, struct winsize *ws);
385 	int (*get_icount)(struct tty_struct *tty,
386 				struct serial_icounter_struct *icount);
387 	int  (*get_serial)(struct tty_struct *tty, struct serial_struct *p);
388 	int  (*set_serial)(struct tty_struct *tty, struct serial_struct *p);
389 	void (*show_fdinfo)(struct tty_struct *tty, struct seq_file *m);
390 #ifdef CONFIG_CONSOLE_POLL
391 	int (*poll_init)(struct tty_driver *driver, int line, char *options);
392 	int (*poll_get_char)(struct tty_driver *driver, int line);
393 	void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
394 #endif
395 	int (*proc_show)(struct seq_file *m, void *driver);
396 
397 	ANDROID_KABI_RESERVE(1);
398 	ANDROID_KABI_RESERVE(2);
399 } __randomize_layout;
400 
401 /**
402  * struct tty_driver -- driver for TTY devices
403  *
404  * @kref: reference counting. Reaching zero frees all the internals and the
405  *	  driver.
406  * @cdevs: allocated/registered character /dev devices
407  * @owner: modules owning this driver. Used drivers cannot be rmmod'ed.
408  *	   Automatically set by tty_alloc_driver().
409  * @driver_name: name of the driver used in /proc/tty
410  * @name: used for constructing /dev node name
411  * @name_base: used as a number base for constructing /dev node name
412  * @major: major /dev device number (zero for autoassignment)
413  * @minor_start: the first minor /dev device number
414  * @num: number of devices allocated
415  * @type: type of tty driver (%TTY_DRIVER_TYPE_)
416  * @subtype: subtype of tty driver (%SYSTEM_TYPE_, %PTY_TYPE_, %SERIAL_TYPE_)
417  * @init_termios: termios to set to each tty initially (e.g. %tty_std_termios)
418  * @flags: tty driver flags (%TTY_DRIVER_)
419  * @proc_entry: proc fs entry, used internally
420  * @other: driver of the linked tty; only used for the PTY driver
421  * @ttys: array of active &struct tty_struct, set by tty_standard_install()
422  * @ports: array of &struct tty_port; can be set during initialization by
423  *	   tty_port_link_device() and similar
424  * @termios: storage for termios at each TTY close for the next open
425  * @driver_state: pointer to driver's arbitrary data
426  * @ops: driver hooks for TTYs. Set them using tty_set_operations(). Use &struct
427  *	 tty_port helpers in them as much as possible.
428  * @tty_drivers: used internally to link tty_drivers together
429  *
430  * The usual handling of &struct tty_driver is to allocate it by
431  * tty_alloc_driver(), set up all the necessary members, and register it by
432  * tty_register_driver(). At last, the driver is torn down by calling
433  * tty_unregister_driver() followed by tty_driver_kref_put().
434  *
435  * The fields required to be set before calling tty_register_driver() include
436  * @driver_name, @name, @type, @subtype, @init_termios, and @ops.
437  */
438 struct tty_driver {
439 	struct kref kref;
440 	struct cdev **cdevs;
441 	struct module	*owner;
442 	const char	*driver_name;
443 	const char	*name;
444 	int	name_base;
445 	int	major;
446 	int	minor_start;
447 	unsigned int	num;
448 	short	type;
449 	short	subtype;
450 	struct ktermios init_termios;
451 	unsigned long	flags;
452 	struct proc_dir_entry *proc_entry;
453 	struct tty_driver *other;
454 
455 	/*
456 	 * Pointer to the tty data structures
457 	 */
458 	struct tty_struct **ttys;
459 	struct tty_port **ports;
460 	struct ktermios **termios;
461 	void *driver_state;
462 
463 	/*
464 	 * Driver methods
465 	 */
466 
467 	const struct tty_operations *ops;
468 	struct list_head tty_drivers;
469 
470 	ANDROID_KABI_RESERVE(1);
471 	ANDROID_KABI_RESERVE(2);
472 } __randomize_layout;
473 
474 extern struct list_head tty_drivers;
475 
476 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
477 		unsigned long flags);
478 struct tty_driver *tty_find_polling_driver(char *name, int *line);
479 
480 void tty_driver_kref_put(struct tty_driver *driver);
481 
482 /* Use TTY_DRIVER_* flags below */
483 #define tty_alloc_driver(lines, flags) \
484 		__tty_alloc_driver(lines, THIS_MODULE, flags)
485 
tty_driver_kref_get(struct tty_driver * d)486 static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
487 {
488 	kref_get(&d->kref);
489 	return d;
490 }
491 
tty_set_operations(struct tty_driver * driver,const struct tty_operations * op)492 static inline void tty_set_operations(struct tty_driver *driver,
493 		const struct tty_operations *op)
494 {
495 	driver->ops = op;
496 }
497 
498 /**
499  * DOC: TTY Driver Flags
500  *
501  * TTY_DRIVER_RESET_TERMIOS
502  *	Requests the tty layer to reset the termios setting when the last
503  *	process has closed the device. Used for PTYs, in particular.
504  *
505  * TTY_DRIVER_REAL_RAW
506  *	Indicates that the driver will guarantee not to set any special
507  *	character handling flags if this is set for the tty:
508  *
509  *	``(IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR || !INPCK)``
510  *
511  *	That is, if there is no reason for the driver to
512  *	send notifications of parity and break characters up to the line
513  *	driver, it won't do so.  This allows the line driver to optimize for
514  *	this case if this flag is set.  (Note that there is also a promise, if
515  *	the above case is true, not to signal overruns, either.)
516  *
517  * TTY_DRIVER_DYNAMIC_DEV
518  *	The individual tty devices need to be registered with a call to
519  *	tty_register_device() when the device is found in the system and
520  *	unregistered with a call to tty_unregister_device() so the devices will
521  *	be show up properly in sysfs.  If not set, all &tty_driver.num entries
522  *	will be created by the tty core in sysfs when tty_register_driver() is
523  *	called.  This is to be used by drivers that have tty devices that can
524  *	appear and disappear while the main tty driver is registered with the
525  *	tty core.
526  *
527  * TTY_DRIVER_DEVPTS_MEM
528  *	Don't use the standard arrays (&tty_driver.ttys and
529  *	&tty_driver.termios), instead use dynamic memory keyed through the
530  *	devpts filesystem. This is only applicable to the PTY driver.
531  *
532  * TTY_DRIVER_HARDWARE_BREAK
533  *	Hardware handles break signals. Pass the requested timeout to the
534  *	&tty_operations.break_ctl instead of using a simple on/off interface.
535  *
536  * TTY_DRIVER_DYNAMIC_ALLOC
537  *	Do not allocate structures which are needed per line for this driver
538  *	(&tty_driver.ports) as it would waste memory. The driver will take
539  *	care. This is only applicable to the PTY driver.
540  *
541  * TTY_DRIVER_UNNUMBERED_NODE
542  *	Do not create numbered ``/dev`` nodes. For example, create
543  *	``/dev/ttyprintk`` and not ``/dev/ttyprintk0``. Applicable only when a
544  *	driver for a single tty device is being allocated.
545  */
546 #define TTY_DRIVER_INSTALLED		0x0001
547 #define TTY_DRIVER_RESET_TERMIOS	0x0002
548 #define TTY_DRIVER_REAL_RAW		0x0004
549 #define TTY_DRIVER_DYNAMIC_DEV		0x0008
550 #define TTY_DRIVER_DEVPTS_MEM		0x0010
551 #define TTY_DRIVER_HARDWARE_BREAK	0x0020
552 #define TTY_DRIVER_DYNAMIC_ALLOC	0x0040
553 #define TTY_DRIVER_UNNUMBERED_NODE	0x0080
554 
555 /* tty driver types */
556 #define TTY_DRIVER_TYPE_SYSTEM		0x0001
557 #define TTY_DRIVER_TYPE_CONSOLE		0x0002
558 #define TTY_DRIVER_TYPE_SERIAL		0x0003
559 #define TTY_DRIVER_TYPE_PTY		0x0004
560 #define TTY_DRIVER_TYPE_SCC		0x0005	/* scc driver */
561 #define TTY_DRIVER_TYPE_SYSCONS		0x0006
562 
563 /* system subtypes (magic, used by tty_io.c) */
564 #define SYSTEM_TYPE_TTY			0x0001
565 #define SYSTEM_TYPE_CONSOLE		0x0002
566 #define SYSTEM_TYPE_SYSCONS		0x0003
567 #define SYSTEM_TYPE_SYSPTMX		0x0004
568 
569 /* pty subtypes (magic, used by tty_io.c) */
570 #define PTY_TYPE_MASTER			0x0001
571 #define PTY_TYPE_SLAVE			0x0002
572 
573 /* serial subtype definitions */
574 #define SERIAL_TYPE_NORMAL	1
575 
576 int tty_register_driver(struct tty_driver *driver);
577 void tty_unregister_driver(struct tty_driver *driver);
578 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
579 		struct device *dev);
580 struct device *tty_register_device_attr(struct tty_driver *driver,
581 		unsigned index, struct device *device, void *drvdata,
582 		const struct attribute_group **attr_grp);
583 void tty_unregister_device(struct tty_driver *driver, unsigned index);
584 
585 #ifdef CONFIG_PROC_FS
586 void proc_tty_register_driver(struct tty_driver *);
587 void proc_tty_unregister_driver(struct tty_driver *);
588 #else
proc_tty_register_driver(struct tty_driver * d)589 static inline void proc_tty_register_driver(struct tty_driver *d) {}
proc_tty_unregister_driver(struct tty_driver * d)590 static inline void proc_tty_unregister_driver(struct tty_driver *d) {}
591 #endif
592 
593 #endif /* #ifdef _LINUX_TTY_DRIVER_H */
594