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 unsigned char *buf,
76 * size_t 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 ssize_t (*write)(struct tty_struct *tty, const u8 *buf, size_t count);
360 int (*put_char)(struct tty_struct *tty, u8 ch);
361 void (*flush_chars)(struct tty_struct *tty);
362 unsigned int (*write_room)(struct tty_struct *tty);
363 unsigned int (*chars_in_buffer)(struct tty_struct *tty);
364 int (*ioctl)(struct tty_struct *tty,
365 unsigned int cmd, unsigned long arg);
366 long (*compat_ioctl)(struct tty_struct *tty,
367 unsigned int cmd, unsigned long arg);
368 void (*set_termios)(struct tty_struct *tty, const struct ktermios *old);
369 void (*throttle)(struct tty_struct * tty);
370 void (*unthrottle)(struct tty_struct * tty);
371 void (*stop)(struct tty_struct *tty);
372 void (*start)(struct tty_struct *tty);
373 void (*hangup)(struct tty_struct *tty);
374 int (*break_ctl)(struct tty_struct *tty, int state);
375 void (*flush_buffer)(struct tty_struct *tty);
376 void (*set_ldisc)(struct tty_struct *tty);
377 void (*wait_until_sent)(struct tty_struct *tty, int timeout);
378 void (*send_xchar)(struct tty_struct *tty, char ch);
379 int (*tiocmget)(struct tty_struct *tty);
380 int (*tiocmset)(struct tty_struct *tty,
381 unsigned int set, unsigned int clear);
382 int (*resize)(struct tty_struct *tty, struct winsize *ws);
383 int (*get_icount)(struct tty_struct *tty,
384 struct serial_icounter_struct *icount);
385 int (*get_serial)(struct tty_struct *tty, struct serial_struct *p);
386 int (*set_serial)(struct tty_struct *tty, struct serial_struct *p);
387 void (*show_fdinfo)(struct tty_struct *tty, struct seq_file *m);
388 #ifdef CONFIG_CONSOLE_POLL
389 int (*poll_init)(struct tty_driver *driver, int line, char *options);
390 int (*poll_get_char)(struct tty_driver *driver, int line);
391 void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
392 #endif
393 int (*proc_show)(struct seq_file *m, void *driver);
394 } __randomize_layout;
395
396 /**
397 * struct tty_driver -- driver for TTY devices
398 *
399 * @kref: reference counting. Reaching zero frees all the internals and the
400 * driver.
401 * @cdevs: allocated/registered character /dev devices
402 * @owner: modules owning this driver. Used drivers cannot be rmmod'ed.
403 * Automatically set by tty_alloc_driver().
404 * @driver_name: name of the driver used in /proc/tty
405 * @name: used for constructing /dev node name
406 * @name_base: used as a number base for constructing /dev node name
407 * @major: major /dev device number (zero for autoassignment)
408 * @minor_start: the first minor /dev device number
409 * @num: number of devices allocated
410 * @type: type of tty driver (%TTY_DRIVER_TYPE_)
411 * @subtype: subtype of tty driver (%SYSTEM_TYPE_, %PTY_TYPE_, %SERIAL_TYPE_)
412 * @init_termios: termios to set to each tty initially (e.g. %tty_std_termios)
413 * @flags: tty driver flags (%TTY_DRIVER_)
414 * @proc_entry: proc fs entry, used internally
415 * @other: driver of the linked tty; only used for the PTY driver
416 * @ttys: array of active &struct tty_struct, set by tty_standard_install()
417 * @ports: array of &struct tty_port; can be set during initialization by
418 * tty_port_link_device() and similar
419 * @termios: storage for termios at each TTY close for the next open
420 * @driver_state: pointer to driver's arbitrary data
421 * @ops: driver hooks for TTYs. Set them using tty_set_operations(). Use &struct
422 * tty_port helpers in them as much as possible.
423 * @tty_drivers: used internally to link tty_drivers together
424 *
425 * The usual handling of &struct tty_driver is to allocate it by
426 * tty_alloc_driver(), set up all the necessary members, and register it by
427 * tty_register_driver(). At last, the driver is torn down by calling
428 * tty_unregister_driver() followed by tty_driver_kref_put().
429 *
430 * The fields required to be set before calling tty_register_driver() include
431 * @driver_name, @name, @type, @subtype, @init_termios, and @ops.
432 */
433 struct tty_driver {
434 struct kref kref;
435 struct cdev **cdevs;
436 struct module *owner;
437 const char *driver_name;
438 const char *name;
439 int name_base;
440 int major;
441 int minor_start;
442 unsigned int num;
443 short type;
444 short subtype;
445 struct ktermios init_termios;
446 unsigned long flags;
447 struct proc_dir_entry *proc_entry;
448 struct tty_driver *other;
449
450 /*
451 * Pointer to the tty data structures
452 */
453 struct tty_struct **ttys;
454 struct tty_port **ports;
455 struct ktermios **termios;
456 void *driver_state;
457
458 /*
459 * Driver methods
460 */
461
462 const struct tty_operations *ops;
463 struct list_head tty_drivers;
464 } __randomize_layout;
465
466 extern struct list_head tty_drivers;
467
468 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
469 unsigned long flags);
470 struct tty_driver *tty_find_polling_driver(char *name, int *line);
471
472 void tty_driver_kref_put(struct tty_driver *driver);
473
474 /* Use TTY_DRIVER_* flags below */
475 #define tty_alloc_driver(lines, flags) \
476 __tty_alloc_driver(lines, THIS_MODULE, flags)
477
tty_driver_kref_get(struct tty_driver * d)478 static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
479 {
480 kref_get(&d->kref);
481 return d;
482 }
483
tty_set_operations(struct tty_driver * driver,const struct tty_operations * op)484 static inline void tty_set_operations(struct tty_driver *driver,
485 const struct tty_operations *op)
486 {
487 driver->ops = op;
488 }
489
490 /**
491 * DOC: TTY Driver Flags
492 *
493 * TTY_DRIVER_RESET_TERMIOS
494 * Requests the tty layer to reset the termios setting when the last
495 * process has closed the device. Used for PTYs, in particular.
496 *
497 * TTY_DRIVER_REAL_RAW
498 * Indicates that the driver will guarantee not to set any special
499 * character handling flags if this is set for the tty:
500 *
501 * ``(IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR || !INPCK)``
502 *
503 * That is, if there is no reason for the driver to
504 * send notifications of parity and break characters up to the line
505 * driver, it won't do so. This allows the line driver to optimize for
506 * this case if this flag is set. (Note that there is also a promise, if
507 * the above case is true, not to signal overruns, either.)
508 *
509 * TTY_DRIVER_DYNAMIC_DEV
510 * The individual tty devices need to be registered with a call to
511 * tty_register_device() when the device is found in the system and
512 * unregistered with a call to tty_unregister_device() so the devices will
513 * be show up properly in sysfs. If not set, all &tty_driver.num entries
514 * will be created by the tty core in sysfs when tty_register_driver() is
515 * called. This is to be used by drivers that have tty devices that can
516 * appear and disappear while the main tty driver is registered with the
517 * tty core.
518 *
519 * TTY_DRIVER_DEVPTS_MEM
520 * Don't use the standard arrays (&tty_driver.ttys and
521 * &tty_driver.termios), instead use dynamic memory keyed through the
522 * devpts filesystem. This is only applicable to the PTY driver.
523 *
524 * TTY_DRIVER_HARDWARE_BREAK
525 * Hardware handles break signals. Pass the requested timeout to the
526 * &tty_operations.break_ctl instead of using a simple on/off interface.
527 *
528 * TTY_DRIVER_DYNAMIC_ALLOC
529 * Do not allocate structures which are needed per line for this driver
530 * (&tty_driver.ports) as it would waste memory. The driver will take
531 * care. This is only applicable to the PTY driver.
532 *
533 * TTY_DRIVER_UNNUMBERED_NODE
534 * Do not create numbered ``/dev`` nodes. For example, create
535 * ``/dev/ttyprintk`` and not ``/dev/ttyprintk0``. Applicable only when a
536 * driver for a single tty device is being allocated.
537 */
538 #define TTY_DRIVER_INSTALLED 0x0001
539 #define TTY_DRIVER_RESET_TERMIOS 0x0002
540 #define TTY_DRIVER_REAL_RAW 0x0004
541 #define TTY_DRIVER_DYNAMIC_DEV 0x0008
542 #define TTY_DRIVER_DEVPTS_MEM 0x0010
543 #define TTY_DRIVER_HARDWARE_BREAK 0x0020
544 #define TTY_DRIVER_DYNAMIC_ALLOC 0x0040
545 #define TTY_DRIVER_UNNUMBERED_NODE 0x0080
546
547 /* tty driver types */
548 #define TTY_DRIVER_TYPE_SYSTEM 0x0001
549 #define TTY_DRIVER_TYPE_CONSOLE 0x0002
550 #define TTY_DRIVER_TYPE_SERIAL 0x0003
551 #define TTY_DRIVER_TYPE_PTY 0x0004
552 #define TTY_DRIVER_TYPE_SCC 0x0005 /* scc driver */
553 #define TTY_DRIVER_TYPE_SYSCONS 0x0006
554
555 /* system subtypes (magic, used by tty_io.c) */
556 #define SYSTEM_TYPE_TTY 0x0001
557 #define SYSTEM_TYPE_CONSOLE 0x0002
558 #define SYSTEM_TYPE_SYSCONS 0x0003
559 #define SYSTEM_TYPE_SYSPTMX 0x0004
560
561 /* pty subtypes (magic, used by tty_io.c) */
562 #define PTY_TYPE_MASTER 0x0001
563 #define PTY_TYPE_SLAVE 0x0002
564
565 /* serial subtype definitions */
566 #define SERIAL_TYPE_NORMAL 1
567
568 int tty_register_driver(struct tty_driver *driver);
569 void tty_unregister_driver(struct tty_driver *driver);
570 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
571 struct device *dev);
572 struct device *tty_register_device_attr(struct tty_driver *driver,
573 unsigned index, struct device *device, void *drvdata,
574 const struct attribute_group **attr_grp);
575 void tty_unregister_device(struct tty_driver *driver, unsigned index);
576
577 #ifdef CONFIG_PROC_FS
578 void proc_tty_register_driver(struct tty_driver *);
579 void proc_tty_unregister_driver(struct tty_driver *);
580 #else
proc_tty_register_driver(struct tty_driver * d)581 static inline void proc_tty_register_driver(struct tty_driver *d) {}
proc_tty_unregister_driver(struct tty_driver * d)582 static inline void proc_tty_unregister_driver(struct tty_driver *d) {}
583 #endif
584
585 #endif /* #ifdef _LINUX_TTY_DRIVER_H */
586