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: ``ssize_t ()(struct tty_struct *tty, const u8 *buf, size_t count)``
76   *
77   *	This routine is called by the kernel to write a series (@count) of
78   *	characters (@buf) to the @tty device. The characters may come from
79   *	user space or kernel space.  This routine will return the
80   *	number of characters actually accepted for writing.
81   *
82   *	May occur in parallel in special cases. Because this includes panic
83   *	paths drivers generally shouldn't try and do clever locking here.
84   *
85   *	Optional: Required for writable devices. May not sleep.
86   *
87   * @put_char: ``int ()(struct tty_struct *tty, u8 ch)``
88   *
89   *	This routine is called by the kernel to write a single character @ch to
90   *	the @tty device. If the kernel uses this routine, it must call the
91   *	@flush_chars() routine (if defined) when it is done stuffing characters
92   *	into the driver. If there is no room in the queue, the character is
93   *	ignored.
94   *
95   *	Optional: Kernel will use the @write method if not provided. Do not
96   *	call this function directly, call tty_put_char().
97   *
98   * @flush_chars: ``void ()(struct tty_struct *tty)``
99   *
100   *	This routine is called by the kernel after it has written a
101   *	series of characters to the tty device using @put_char().
102   *
103   *	Optional. Do not call this function directly, call
104   *	tty_driver_flush_chars().
105   *
106   * @write_room: ``unsigned int ()(struct tty_struct *tty)``
107   *
108   *	This routine returns the numbers of characters the @tty driver
109   *	will accept for queuing to be written.  This number is subject
110   *	to change as output buffers get emptied, or if the output flow
111   *	control is acted.
112   *
113   *	The ldisc is responsible for being intelligent about multi-threading of
114   *	write_room/write calls
115   *
116   *	Required if @write method is provided else not needed. Do not call this
117   *	function directly, call tty_write_room()
118   *
119   * @chars_in_buffer: ``unsigned int ()(struct tty_struct *tty)``
120   *
121   *	This routine returns the number of characters in the device private
122   *	output queue. Used in tty_wait_until_sent() and for poll()
123   *	implementation.
124   *
125   *	Optional: if not provided, it is assumed there is no queue on the
126   *	device. Do not call this function directly, call tty_chars_in_buffer().
127   *
128   * @ioctl: ``int ()(struct tty_struct *tty, unsigned int cmd,
129   *		    unsigned long arg)``
130   *
131   *	This routine allows the @tty driver to implement device-specific
132   *	ioctls. If the ioctl number passed in @cmd is not recognized by the
133   *	driver, it should return %ENOIOCTLCMD.
134   *
135   *	Optional.
136   *
137   * @compat_ioctl: ``long ()(struct tty_struct *tty, unsigned int cmd,
138   *			  unsigned long arg)``
139   *
140   *	Implement ioctl processing for 32 bit process on 64 bit system.
141   *
142   *	Optional.
143   *
144   * @set_termios: ``void ()(struct tty_struct *tty, const struct ktermios *old)``
145   *
146   *	This routine allows the @tty driver to be notified when device's
147   *	termios settings have changed. New settings are in @tty->termios.
148   *	Previous settings are passed in the @old argument.
149   *
150   *	The API is defined such that the driver should return the actual modes
151   *	selected. This means that the driver is responsible for modifying any
152   *	bits in @tty->termios it cannot fulfill to indicate the actual modes
153   *	being used.
154   *
155   *	Optional. Called under the @tty->termios_rwsem. May sleep.
156   *
157   * @ldisc_ok: ``int ()(struct tty_struct *tty, int ldisc)``
158   *
159   *	This routine allows the @tty driver to decide if it can deal
160   *	with a particular @ldisc.
161   *
162   *	Optional. Called under the @tty->ldisc_sem and @tty->termios_rwsem.
163   *
164   * @set_ldisc: ``void ()(struct tty_struct *tty)``
165   *
166   *	This routine allows the @tty driver to be notified when the device's
167   *	line discipline is being changed. At the point this is done the
168   *	discipline is not yet usable.
169   *
170   *	Optional. Called under the @tty->ldisc_sem and @tty->termios_rwsem.
171   *
172   * @throttle: ``void ()(struct tty_struct *tty)``
173   *
174   *	This routine notifies the @tty driver that input buffers for the line
175   *	discipline are close to full, and it should somehow signal that no more
176   *	characters should be sent to the @tty.
177   *
178   *	Serialization including with @unthrottle() is the job of the ldisc
179   *	layer.
180   *
181   *	Optional: Always invoke via tty_throttle_safe(). Called under the
182   *	@tty->termios_rwsem.
183   *
184   * @unthrottle: ``void ()(struct tty_struct *tty)``
185   *
186   *	This routine notifies the @tty driver that it should signal that
187   *	characters can now be sent to the @tty without fear of overrunning the
188   *	input buffers of the line disciplines.
189   *
190   *	Optional. Always invoke via tty_unthrottle(). Called under the
191   *	@tty->termios_rwsem.
192   *
193   * @stop: ``void ()(struct tty_struct *tty)``
194   *
195   *	This routine notifies the @tty driver that it should stop outputting
196   *	characters to the tty device.
197   *
198   *	Called with @tty->flow.lock held. Serialized with @start() method.
199   *
200   *	Optional. Always invoke via stop_tty().
201   *
202   * @start: ``void ()(struct tty_struct *tty)``
203   *
204   *	This routine notifies the @tty driver that it resumed sending
205   *	characters to the @tty device.
206   *
207   *	Called with @tty->flow.lock held. Serialized with stop() method.
208   *
209   *	Optional. Always invoke via start_tty().
210   *
211   * @hangup: ``void ()(struct tty_struct *tty)``
212   *
213   *	This routine notifies the @tty driver that it should hang up the @tty
214   *	device.
215   *
216   *	Optional. Called with tty lock held.
217   *
218   * @break_ctl: ``int ()(struct tty_struct *tty, int state)``
219   *
220   *	This optional routine requests the @tty driver to turn on or off BREAK
221   *	status on the RS-232 port. If @state is -1, then the BREAK status
222   *	should be turned on; if @state is 0, then BREAK should be turned off.
223   *
224   *	If this routine is implemented, the high-level tty driver will handle
225   *	the following ioctls: %TCSBRK, %TCSBRKP, %TIOCSBRK, %TIOCCBRK.
226   *
227   *	If the driver sets %TTY_DRIVER_HARDWARE_BREAK in tty_alloc_driver(),
228   *	then the interface will also be called with actual times and the
229   *	hardware is expected to do the delay work itself. 0 and -1 are still
230   *	used for on/off.
231   *
232   *	Optional: Required for %TCSBRK/%BRKP/etc. handling. May sleep.
233   *
234   * @flush_buffer: ``void ()(struct tty_struct *tty)``
235   *
236   *	This routine discards device private output buffer. Invoked on close,
237   *	hangup, to implement %TCOFLUSH ioctl and similar.
238   *
239   *	Optional: if not provided, it is assumed there is no queue on the
240   *	device. Do not call this function directly, call
241   *	tty_driver_flush_buffer().
242   *
243   * @wait_until_sent: ``void ()(struct tty_struct *tty, int timeout)``
244   *
245   *	This routine waits until the device has written out all of the
246   *	characters in its transmitter FIFO. Or until @timeout (in jiffies) is
247   *	reached.
248   *
249   *	Optional: If not provided, the device is assumed to have no FIFO.
250   *	Usually correct to invoke via tty_wait_until_sent(). May sleep.
251   *
252   * @send_xchar: ``void ()(struct tty_struct *tty, u8 ch)``
253   *
254   *	This routine is used to send a high-priority XON/XOFF character (@ch)
255   *	to the @tty device.
256   *
257   *	Optional: If not provided, then the @write method is called under
258   *	the @tty->atomic_write_lock to keep it serialized with the ldisc.
259   *
260   * @tiocmget: ``int ()(struct tty_struct *tty)``
261   *
262   *	This routine is used to obtain the modem status bits from the @tty
263   *	driver.
264   *
265   *	Optional: If not provided, then %ENOTTY is returned from the %TIOCMGET
266   *	ioctl. Do not call this function directly, call tty_tiocmget().
267   *
268   * @tiocmset: ``int ()(struct tty_struct *tty,
269   *		       unsigned int set, unsigned int clear)``
270   *
271   *	This routine is used to set the modem status bits to the @tty driver.
272   *	First, @clear bits should be cleared, then @set bits set.
273   *
274   *	Optional: If not provided, then %ENOTTY is returned from the %TIOCMSET
275   *	ioctl. Do not call this function directly, call tty_tiocmset().
276   *
277   * @resize: ``int ()(struct tty_struct *tty, struct winsize *ws)``
278   *
279   *	Called when a termios request is issued which changes the requested
280   *	terminal geometry to @ws.
281   *
282   *	Optional: the default action is to update the termios structure
283   *	without error. This is usually the correct behaviour. Drivers should
284   *	not force errors here if they are not resizable objects (e.g. a serial
285   *	line). See tty_do_resize() if you need to wrap the standard method
286   *	in your own logic -- the usual case.
287   *
288   * @get_icount: ``int ()(struct tty_struct *tty,
289   *			 struct serial_icounter *icount)``
290   *
291   *	Called when the @tty device receives a %TIOCGICOUNT ioctl. Passed a
292   *	kernel structure @icount to complete.
293   *
294   *	Optional: called only if provided, otherwise %ENOTTY will be returned.
295   *
296   * @get_serial: ``int ()(struct tty_struct *tty, struct serial_struct *p)``
297   *
298   *	Called when the @tty device receives a %TIOCGSERIAL ioctl. Passed a
299   *	kernel structure @p (&struct serial_struct) to complete.
300   *
301   *	Optional: called only if provided, otherwise %ENOTTY will be returned.
302   *	Do not call this function directly, call tty_tiocgserial().
303   *
304   * @set_serial: ``int ()(struct tty_struct *tty, struct serial_struct *p)``
305   *
306   *	Called when the @tty device receives a %TIOCSSERIAL ioctl. Passed a
307   *	kernel structure @p (&struct serial_struct) to set the values from.
308   *
309   *	Optional: called only if provided, otherwise %ENOTTY will be returned.
310   *	Do not call this function directly, call tty_tiocsserial().
311   *
312   * @show_fdinfo: ``void ()(struct tty_struct *tty, struct seq_file *m)``
313   *
314   *	Called when the @tty device file descriptor receives a fdinfo request
315   *	from VFS (to show in /proc/<pid>/fdinfo/). @m should be filled with
316   *	information.
317   *
318   *	Optional: called only if provided, otherwise nothing is written to @m.
319   *	Do not call this function directly, call tty_show_fdinfo().
320   *
321   * @poll_init: ``int ()(struct tty_driver *driver, int line, char *options)``
322   *
323   *	kgdboc support (Documentation/dev-tools/kgdb.rst). This routine is
324   *	called to initialize the HW for later use by calling @poll_get_char or
325   *	@poll_put_char.
326   *
327   *	Optional: called only if provided, otherwise skipped as a non-polling
328   *	driver.
329   *
330   * @poll_get_char: ``int ()(struct tty_driver *driver, int line)``
331   *
332   *	kgdboc support (see @poll_init). @driver should read a character from a
333   *	tty identified by @line and return it.
334   *
335   *	Optional: called only if @poll_init provided.
336   *
337   * @poll_put_char: ``void ()(struct tty_driver *driver, int line, char ch)``
338   *
339   *	kgdboc support (see @poll_init). @driver should write character @ch to
340   *	a tty identified by @line.
341   *
342   *	Optional: called only if @poll_init provided.
343   *
344   * @proc_show: ``int ()(struct seq_file *m, void *driver)``
345   *
346   *	Driver @driver (cast to &struct tty_driver) can show additional info in
347   *	/proc/tty/driver/<driver_name>. It is enough to fill in the information
348   *	into @m.
349   *
350   *	Optional: called only if provided, otherwise no /proc entry created.
351   *
352   * This structure defines the interface between the low-level tty driver and
353   * the tty routines. These routines can be defined. Unless noted otherwise,
354   * they are optional, and can be filled in with a %NULL pointer.
355   */
356  struct tty_operations {
357  	struct tty_struct * (*lookup)(struct tty_driver *driver,
358  			struct file *filp, int idx);
359  	int  (*install)(struct tty_driver *driver, struct tty_struct *tty);
360  	void (*remove)(struct tty_driver *driver, struct tty_struct *tty);
361  	int  (*open)(struct tty_struct * tty, struct file * filp);
362  	void (*close)(struct tty_struct * tty, struct file * filp);
363  	void (*shutdown)(struct tty_struct *tty);
364  	void (*cleanup)(struct tty_struct *tty);
365  	ssize_t (*write)(struct tty_struct *tty, const u8 *buf, size_t count);
366  	int  (*put_char)(struct tty_struct *tty, u8 ch);
367  	void (*flush_chars)(struct tty_struct *tty);
368  	unsigned int (*write_room)(struct tty_struct *tty);
369  	unsigned int (*chars_in_buffer)(struct tty_struct *tty);
370  	int  (*ioctl)(struct tty_struct *tty,
371  		    unsigned int cmd, unsigned long arg);
372  	long (*compat_ioctl)(struct tty_struct *tty,
373  			     unsigned int cmd, unsigned long arg);
374  	void (*set_termios)(struct tty_struct *tty, const struct ktermios *old);
375  	void (*throttle)(struct tty_struct * tty);
376  	void (*unthrottle)(struct tty_struct * tty);
377  	void (*stop)(struct tty_struct *tty);
378  	void (*start)(struct tty_struct *tty);
379  	void (*hangup)(struct tty_struct *tty);
380  	int (*break_ctl)(struct tty_struct *tty, int state);
381  	void (*flush_buffer)(struct tty_struct *tty);
382  	int (*ldisc_ok)(struct tty_struct *tty, int ldisc);
383  	void (*set_ldisc)(struct tty_struct *tty);
384  	void (*wait_until_sent)(struct tty_struct *tty, int timeout);
385  	void (*send_xchar)(struct tty_struct *tty, u8 ch);
386  	int (*tiocmget)(struct tty_struct *tty);
387  	int (*tiocmset)(struct tty_struct *tty,
388  			unsigned int set, unsigned int clear);
389  	int (*resize)(struct tty_struct *tty, struct winsize *ws);
390  	int (*get_icount)(struct tty_struct *tty,
391  				struct serial_icounter_struct *icount);
392  	int  (*get_serial)(struct tty_struct *tty, struct serial_struct *p);
393  	int  (*set_serial)(struct tty_struct *tty, struct serial_struct *p);
394  	void (*show_fdinfo)(struct tty_struct *tty, struct seq_file *m);
395  #ifdef CONFIG_CONSOLE_POLL
396  	int (*poll_init)(struct tty_driver *driver, int line, char *options);
397  	int (*poll_get_char)(struct tty_driver *driver, int line);
398  	void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
399  #endif
400  	int (*proc_show)(struct seq_file *m, void *driver);
401  } __randomize_layout;
402  
403  /**
404   * struct tty_driver -- driver for TTY devices
405   *
406   * @kref: reference counting. Reaching zero frees all the internals and the
407   *	  driver.
408   * @cdevs: allocated/registered character /dev devices
409   * @owner: modules owning this driver. Used drivers cannot be rmmod'ed.
410   *	   Automatically set by tty_alloc_driver().
411   * @driver_name: name of the driver used in /proc/tty
412   * @name: used for constructing /dev node name
413   * @name_base: used as a number base for constructing /dev node name
414   * @major: major /dev device number (zero for autoassignment)
415   * @minor_start: the first minor /dev device number
416   * @num: number of devices allocated
417   * @type: type of tty driver (%TTY_DRIVER_TYPE_)
418   * @subtype: subtype of tty driver (%SYSTEM_TYPE_, %PTY_TYPE_, %SERIAL_TYPE_)
419   * @init_termios: termios to set to each tty initially (e.g. %tty_std_termios)
420   * @flags: tty driver flags (%TTY_DRIVER_)
421   * @proc_entry: proc fs entry, used internally
422   * @other: driver of the linked tty; only used for the PTY driver
423   * @ttys: array of active &struct tty_struct, set by tty_standard_install()
424   * @ports: array of &struct tty_port; can be set during initialization by
425   *	   tty_port_link_device() and similar
426   * @termios: storage for termios at each TTY close for the next open
427   * @driver_state: pointer to driver's arbitrary data
428   * @ops: driver hooks for TTYs. Set them using tty_set_operations(). Use &struct
429   *	 tty_port helpers in them as much as possible.
430   * @tty_drivers: used internally to link tty_drivers together
431   *
432   * The usual handling of &struct tty_driver is to allocate it by
433   * tty_alloc_driver(), set up all the necessary members, and register it by
434   * tty_register_driver(). At last, the driver is torn down by calling
435   * tty_unregister_driver() followed by tty_driver_kref_put().
436   *
437   * The fields required to be set before calling tty_register_driver() include
438   * @driver_name, @name, @type, @subtype, @init_termios, and @ops.
439   */
440  struct tty_driver {
441  	struct kref kref;
442  	struct cdev **cdevs;
443  	struct module	*owner;
444  	const char	*driver_name;
445  	const char	*name;
446  	int	name_base;
447  	int	major;
448  	int	minor_start;
449  	unsigned int	num;
450  	short	type;
451  	short	subtype;
452  	struct ktermios init_termios;
453  	unsigned long	flags;
454  	struct proc_dir_entry *proc_entry;
455  	struct tty_driver *other;
456  
457  	/*
458  	 * Pointer to the tty data structures
459  	 */
460  	struct tty_struct **ttys;
461  	struct tty_port **ports;
462  	struct ktermios **termios;
463  	void *driver_state;
464  
465  	/*
466  	 * Driver methods
467  	 */
468  
469  	const struct tty_operations *ops;
470  	struct list_head tty_drivers;
471  } __randomize_layout;
472  
473  extern struct list_head tty_drivers;
474  
475  struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
476  		unsigned long flags);
477  struct tty_driver *tty_find_polling_driver(char *name, int *line);
478  
479  void tty_driver_kref_put(struct tty_driver *driver);
480  
481  /* Use TTY_DRIVER_* flags below */
482  #define tty_alloc_driver(lines, flags) \
483  		__tty_alloc_driver(lines, THIS_MODULE, flags)
484  
tty_driver_kref_get(struct tty_driver * d)485  static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
486  {
487  	kref_get(&d->kref);
488  	return d;
489  }
490  
tty_set_operations(struct tty_driver * driver,const struct tty_operations * op)491  static inline void tty_set_operations(struct tty_driver *driver,
492  		const struct tty_operations *op)
493  {
494  	driver->ops = op;
495  }
496  
497  /**
498   * DOC: TTY Driver Flags
499   *
500   * TTY_DRIVER_RESET_TERMIOS
501   *	Requests the tty layer to reset the termios setting when the last
502   *	process has closed the device. Used for PTYs, in particular.
503   *
504   * TTY_DRIVER_REAL_RAW
505   *	Indicates that the driver will guarantee not to set any special
506   *	character handling flags if this is set for the tty:
507   *
508   *	``(IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR || !INPCK)``
509   *
510   *	That is, if there is no reason for the driver to
511   *	send notifications of parity and break characters up to the line
512   *	driver, it won't do so.  This allows the line driver to optimize for
513   *	this case if this flag is set.  (Note that there is also a promise, if
514   *	the above case is true, not to signal overruns, either.)
515   *
516   * TTY_DRIVER_DYNAMIC_DEV
517   *	The individual tty devices need to be registered with a call to
518   *	tty_register_device() when the device is found in the system and
519   *	unregistered with a call to tty_unregister_device() so the devices will
520   *	be show up properly in sysfs.  If not set, all &tty_driver.num entries
521   *	will be created by the tty core in sysfs when tty_register_driver() is
522   *	called.  This is to be used by drivers that have tty devices that can
523   *	appear and disappear while the main tty driver is registered with the
524   *	tty core.
525   *
526   * TTY_DRIVER_DEVPTS_MEM
527   *	Don't use the standard arrays (&tty_driver.ttys and
528   *	&tty_driver.termios), instead use dynamic memory keyed through the
529   *	devpts filesystem. This is only applicable to the PTY driver.
530   *
531   * TTY_DRIVER_HARDWARE_BREAK
532   *	Hardware handles break signals. Pass the requested timeout to the
533   *	&tty_operations.break_ctl instead of using a simple on/off interface.
534   *
535   * TTY_DRIVER_DYNAMIC_ALLOC
536   *	Do not allocate structures which are needed per line for this driver
537   *	(&tty_driver.ports) as it would waste memory. The driver will take
538   *	care. This is only applicable to the PTY driver.
539   *
540   * TTY_DRIVER_UNNUMBERED_NODE
541   *	Do not create numbered ``/dev`` nodes. For example, create
542   *	``/dev/ttyprintk`` and not ``/dev/ttyprintk0``. Applicable only when a
543   *	driver for a single tty device is being allocated.
544   */
545  #define TTY_DRIVER_INSTALLED		0x0001
546  #define TTY_DRIVER_RESET_TERMIOS	0x0002
547  #define TTY_DRIVER_REAL_RAW		0x0004
548  #define TTY_DRIVER_DYNAMIC_DEV		0x0008
549  #define TTY_DRIVER_DEVPTS_MEM		0x0010
550  #define TTY_DRIVER_HARDWARE_BREAK	0x0020
551  #define TTY_DRIVER_DYNAMIC_ALLOC	0x0040
552  #define TTY_DRIVER_UNNUMBERED_NODE	0x0080
553  
554  /* tty driver types */
555  #define TTY_DRIVER_TYPE_SYSTEM		0x0001
556  #define TTY_DRIVER_TYPE_CONSOLE		0x0002
557  #define TTY_DRIVER_TYPE_SERIAL		0x0003
558  #define TTY_DRIVER_TYPE_PTY		0x0004
559  #define TTY_DRIVER_TYPE_SCC		0x0005	/* scc driver */
560  #define TTY_DRIVER_TYPE_SYSCONS		0x0006
561  
562  /* system subtypes (magic, used by tty_io.c) */
563  #define SYSTEM_TYPE_TTY			0x0001
564  #define SYSTEM_TYPE_CONSOLE		0x0002
565  #define SYSTEM_TYPE_SYSCONS		0x0003
566  #define SYSTEM_TYPE_SYSPTMX		0x0004
567  
568  /* pty subtypes (magic, used by tty_io.c) */
569  #define PTY_TYPE_MASTER			0x0001
570  #define PTY_TYPE_SLAVE			0x0002
571  
572  /* serial subtype definitions */
573  #define SERIAL_TYPE_NORMAL	1
574  
575  int tty_register_driver(struct tty_driver *driver);
576  void tty_unregister_driver(struct tty_driver *driver);
577  struct device *tty_register_device(struct tty_driver *driver, unsigned index,
578  		struct device *dev);
579  struct device *tty_register_device_attr(struct tty_driver *driver,
580  		unsigned index, struct device *device, void *drvdata,
581  		const struct attribute_group **attr_grp);
582  void tty_unregister_device(struct tty_driver *driver, unsigned index);
583  
584  #ifdef CONFIG_PROC_FS
585  void proc_tty_register_driver(struct tty_driver *);
586  void proc_tty_unregister_driver(struct tty_driver *);
587  #else
proc_tty_register_driver(struct tty_driver * d)588  static inline void proc_tty_register_driver(struct tty_driver *d) {}
proc_tty_unregister_driver(struct tty_driver * d)589  static inline void proc_tty_unregister_driver(struct tty_driver *d) {}
590  #endif
591  
592  #endif /* #ifdef _LINUX_TTY_DRIVER_H */
593