1 #ifndef _LINUX_TTY_DRIVER_H
2 #define _LINUX_TTY_DRIVER_H
3
4 /*
5 * This structure defines the interface between the low-level tty
6 * driver and the tty routines. The following routines can be
7 * defined; unless noted otherwise, they are optional, and can be
8 * filled in with a null pointer.
9 *
10 * struct tty_struct * (*lookup)(struct tty_driver *self, int idx)
11 *
12 * Return the tty device corresponding to idx, NULL if there is not
13 * one currently in use and an ERR_PTR value on error. Called under
14 * tty_mutex (for now!)
15 *
16 * Optional method. Default behaviour is to use the ttys array
17 *
18 * int (*install)(struct tty_driver *self, struct tty_struct *tty)
19 *
20 * Install a new tty into the tty driver internal tables. Used in
21 * conjunction with lookup and remove methods.
22 *
23 * Optional method. Default behaviour is to use the ttys array
24 *
25 * void (*remove)(struct tty_driver *self, struct tty_struct *tty)
26 *
27 * Remove a closed tty from the tty driver internal tables. Used in
28 * conjunction with lookup and remove methods.
29 *
30 * Optional method. Default behaviour is to use the ttys array
31 *
32 * int (*open)(struct tty_struct * tty, struct file * filp);
33 *
34 * This routine is called when a particular tty device is opened.
35 * This routine is mandatory; if this routine is not filled in,
36 * the attempted open will fail with ENODEV.
37 *
38 * Required method. Called with tty lock held.
39 *
40 * void (*close)(struct tty_struct * tty, struct file * filp);
41 *
42 * This routine is called when a particular tty device is closed.
43 * Note: called even if the corresponding open() failed.
44 *
45 * Required method. Called with tty lock held.
46 *
47 * void (*shutdown)(struct tty_struct * tty);
48 *
49 * This routine is called under the tty lock when a particular tty device
50 * is closed for the last time. It executes before the tty resources
51 * are freed so may execute while another function holds a tty kref.
52 *
53 * void (*cleanup)(struct tty_struct * tty);
54 *
55 * This routine is called asynchronously when a particular tty device
56 * is closed for the last time freeing up the resources. This is
57 * actually the second part of shutdown for routines that might sleep.
58 *
59 *
60 * int (*write)(struct tty_struct * tty,
61 * const unsigned char *buf, int count);
62 *
63 * This routine is called by the kernel to write a series of
64 * characters to the tty device. The characters may come from
65 * user space or kernel space. This routine will return the
66 * number of characters actually accepted for writing.
67 *
68 * Optional: Required for writable devices.
69 *
70 * int (*put_char)(struct tty_struct *tty, unsigned char ch);
71 *
72 * This routine is called by the kernel to write a single
73 * character to the tty device. If the kernel uses this routine,
74 * it must call the flush_chars() routine (if defined) when it is
75 * done stuffing characters into the driver. If there is no room
76 * in the queue, the character is ignored.
77 *
78 * Optional: Kernel will use the write method if not provided.
79 *
80 * Note: Do not call this function directly, call tty_put_char
81 *
82 * void (*flush_chars)(struct tty_struct *tty);
83 *
84 * This routine is called by the kernel after it has written a
85 * series of characters to the tty device using put_char().
86 *
87 * Optional:
88 *
89 * Note: Do not call this function directly, call tty_driver_flush_chars
90 *
91 * int (*write_room)(struct tty_struct *tty);
92 *
93 * This routine returns the numbers of characters the tty driver
94 * will accept for queuing to be written. This number is subject
95 * to change as output buffers get emptied, or if the output flow
96 * control is acted.
97 *
98 * Required if write method is provided else not needed.
99 *
100 * Note: Do not call this function directly, call tty_write_room
101 *
102 * int (*ioctl)(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
103 *
104 * This routine allows the tty driver to implement
105 * device-specific ioctls. If the ioctl number passed in cmd
106 * is not recognized by the driver, it should return ENOIOCTLCMD.
107 *
108 * Optional
109 *
110 * long (*compat_ioctl)(struct tty_struct *tty,,
111 * unsigned int cmd, unsigned long arg);
112 *
113 * implement ioctl processing for 32 bit process on 64 bit system
114 *
115 * Optional
116 *
117 * void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
118 *
119 * This routine allows the tty driver to be notified when
120 * device's termios settings have changed.
121 *
122 * Optional: Called under the termios lock
123 *
124 *
125 * void (*set_ldisc)(struct tty_struct *tty);
126 *
127 * This routine allows the tty driver to be notified when the
128 * device's termios settings have changed.
129 *
130 * Optional: Called under BKL (currently)
131 *
132 * void (*throttle)(struct tty_struct * tty);
133 *
134 * This routine notifies the tty driver that input buffers for
135 * the line discipline are close to full, and it should somehow
136 * signal that no more characters should be sent to the tty.
137 *
138 * Optional: Always invoke via tty_throttle(), called under the
139 * termios lock.
140 *
141 * void (*unthrottle)(struct tty_struct * tty);
142 *
143 * This routine notifies the tty drivers that it should signals
144 * that characters can now be sent to the tty without fear of
145 * overrunning the input buffers of the line disciplines.
146 *
147 * Optional: Always invoke via tty_unthrottle(), called under the
148 * termios lock.
149 *
150 * void (*stop)(struct tty_struct *tty);
151 *
152 * This routine notifies the tty driver that it should stop
153 * outputting characters to the tty device.
154 *
155 * Called with ->flow_lock held. Serialized with start() method.
156 *
157 * Optional:
158 *
159 * Note: Call stop_tty not this method.
160 *
161 * void (*start)(struct tty_struct *tty);
162 *
163 * This routine notifies the tty driver that it resume sending
164 * characters to the tty device.
165 *
166 * Called with ->flow_lock held. Serialized with stop() method.
167 *
168 * Optional:
169 *
170 * Note: Call start_tty not this method.
171 *
172 * void (*hangup)(struct tty_struct *tty);
173 *
174 * This routine notifies the tty driver that it should hang up the
175 * tty device.
176 *
177 * Optional:
178 *
179 * Called with tty lock held.
180 *
181 * int (*break_ctl)(struct tty_struct *tty, int state);
182 *
183 * This optional routine requests the tty driver to turn on or
184 * off BREAK status on the RS-232 port. If state is -1,
185 * then the BREAK status should be turned on; if state is 0, then
186 * BREAK should be turned off.
187 *
188 * If this routine is implemented, the high-level tty driver will
189 * handle the following ioctls: TCSBRK, TCSBRKP, TIOCSBRK,
190 * TIOCCBRK.
191 *
192 * If the driver sets TTY_DRIVER_HARDWARE_BREAK then the interface
193 * will also be called with actual times and the hardware is expected
194 * to do the delay work itself. 0 and -1 are still used for on/off.
195 *
196 * Optional: Required for TCSBRK/BRKP/etc handling.
197 *
198 * void (*wait_until_sent)(struct tty_struct *tty, int timeout);
199 *
200 * This routine waits until the device has written out all of the
201 * characters in its transmitter FIFO.
202 *
203 * Optional: If not provided the device is assumed to have no FIFO
204 *
205 * Note: Usually correct to call tty_wait_until_sent
206 *
207 * void (*send_xchar)(struct tty_struct *tty, char ch);
208 *
209 * This routine is used to send a high-priority XON/XOFF
210 * character to the device.
211 *
212 * Optional: If not provided then the write method is called under
213 * the atomic write lock to keep it serialized with the ldisc.
214 *
215 * int (*resize)(struct tty_struct *tty, struct winsize *ws)
216 *
217 * Called when a termios request is issued which changes the
218 * requested terminal geometry.
219 *
220 * Optional: the default action is to update the termios structure
221 * without error. This is usually the correct behaviour. Drivers should
222 * not force errors here if they are not resizable objects (eg a serial
223 * line). See tty_do_resize() if you need to wrap the standard method
224 * in your own logic - the usual case.
225 *
226 * void (*set_termiox)(struct tty_struct *tty, struct termiox *new);
227 *
228 * Called when the device receives a termiox based ioctl. Passes down
229 * the requested data from user space. This method will not be invoked
230 * unless the tty also has a valid tty->termiox pointer.
231 *
232 * Optional: Called under the termios lock
233 *
234 * int (*get_icount)(struct tty_struct *tty, struct serial_icounter *icount);
235 *
236 * Called when the device receives a TIOCGICOUNT ioctl. Passed a kernel
237 * structure to complete. This method is optional and will only be called
238 * if provided (otherwise EINVAL will be returned).
239 */
240
241 #include <linux/export.h>
242 #include <linux/fs.h>
243 #include <linux/list.h>
244 #include <linux/cdev.h>
245 #include <linux/termios.h>
246
247 struct tty_struct;
248 struct tty_driver;
249 struct serial_icounter_struct;
250
251 struct tty_operations {
252 struct tty_struct * (*lookup)(struct tty_driver *driver,
253 struct inode *inode, int idx);
254 int (*install)(struct tty_driver *driver, struct tty_struct *tty);
255 void (*remove)(struct tty_driver *driver, struct tty_struct *tty);
256 int (*open)(struct tty_struct * tty, struct file * filp);
257 void (*close)(struct tty_struct * tty, struct file * filp);
258 void (*shutdown)(struct tty_struct *tty);
259 void (*cleanup)(struct tty_struct *tty);
260 int (*write)(struct tty_struct * tty,
261 const unsigned char *buf, int count);
262 int (*put_char)(struct tty_struct *tty, unsigned char ch);
263 void (*flush_chars)(struct tty_struct *tty);
264 int (*write_room)(struct tty_struct *tty);
265 int (*chars_in_buffer)(struct tty_struct *tty);
266 int (*ioctl)(struct tty_struct *tty,
267 unsigned int cmd, unsigned long arg);
268 long (*compat_ioctl)(struct tty_struct *tty,
269 unsigned int cmd, unsigned long arg);
270 void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
271 void (*throttle)(struct tty_struct * tty);
272 void (*unthrottle)(struct tty_struct * tty);
273 void (*stop)(struct tty_struct *tty);
274 void (*start)(struct tty_struct *tty);
275 void (*hangup)(struct tty_struct *tty);
276 int (*break_ctl)(struct tty_struct *tty, int state);
277 void (*flush_buffer)(struct tty_struct *tty);
278 void (*set_ldisc)(struct tty_struct *tty);
279 void (*wait_until_sent)(struct tty_struct *tty, int timeout);
280 void (*send_xchar)(struct tty_struct *tty, char ch);
281 int (*tiocmget)(struct tty_struct *tty);
282 int (*tiocmset)(struct tty_struct *tty,
283 unsigned int set, unsigned int clear);
284 int (*resize)(struct tty_struct *tty, struct winsize *ws);
285 int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew);
286 int (*get_icount)(struct tty_struct *tty,
287 struct serial_icounter_struct *icount);
288 #ifdef CONFIG_CONSOLE_POLL
289 int (*poll_init)(struct tty_driver *driver, int line, char *options);
290 int (*poll_get_char)(struct tty_driver *driver, int line);
291 void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
292 #endif
293 const struct file_operations *proc_fops;
294 };
295
296 struct tty_driver {
297 int magic; /* magic number for this structure */
298 struct kref kref; /* Reference management */
299 struct cdev *cdevs;
300 struct module *owner;
301 const char *driver_name;
302 const char *name;
303 int name_base; /* offset of printed name */
304 int major; /* major device number */
305 int minor_start; /* start of minor device number */
306 unsigned int num; /* number of devices allocated */
307 short type; /* type of tty driver */
308 short subtype; /* subtype of tty driver */
309 struct ktermios init_termios; /* Initial termios */
310 unsigned long flags; /* tty driver flags */
311 struct proc_dir_entry *proc_entry; /* /proc fs entry */
312 struct tty_driver *other; /* only used for the PTY driver */
313
314 /*
315 * Pointer to the tty data structures
316 */
317 struct tty_struct **ttys;
318 struct tty_port **ports;
319 struct ktermios **termios;
320 void *driver_state;
321
322 /*
323 * Driver methods
324 */
325
326 const struct tty_operations *ops;
327 struct list_head tty_drivers;
328 };
329
330 extern struct list_head tty_drivers;
331
332 extern struct tty_driver *__tty_alloc_driver(unsigned int lines,
333 struct module *owner, unsigned long flags);
334 extern void put_tty_driver(struct tty_driver *driver);
335 extern void tty_set_operations(struct tty_driver *driver,
336 const struct tty_operations *op);
337 extern struct tty_driver *tty_find_polling_driver(char *name, int *line);
338
339 extern void tty_driver_kref_put(struct tty_driver *driver);
340
341 /* Use TTY_DRIVER_* flags below */
342 #define tty_alloc_driver(lines, flags) \
343 __tty_alloc_driver(lines, THIS_MODULE, flags)
344
345 /*
346 * DEPRECATED Do not use this in new code, use tty_alloc_driver instead.
347 * (And change the return value checks.)
348 */
alloc_tty_driver(unsigned int lines)349 static inline struct tty_driver *alloc_tty_driver(unsigned int lines)
350 {
351 struct tty_driver *ret = tty_alloc_driver(lines, 0);
352 if (IS_ERR(ret))
353 return NULL;
354 return ret;
355 }
356
tty_driver_kref_get(struct tty_driver * d)357 static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
358 {
359 kref_get(&d->kref);
360 return d;
361 }
362
363 /* tty driver magic number */
364 #define TTY_DRIVER_MAGIC 0x5402
365
366 /*
367 * tty driver flags
368 *
369 * TTY_DRIVER_RESET_TERMIOS --- requests the tty layer to reset the
370 * termios setting when the last process has closed the device.
371 * Used for PTY's, in particular.
372 *
373 * TTY_DRIVER_REAL_RAW --- if set, indicates that the driver will
374 * guarantee never not to set any special character handling
375 * flags if ((IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR ||
376 * !INPCK)). That is, if there is no reason for the driver to
377 * send notifications of parity and break characters up to the
378 * line driver, it won't do so. This allows the line driver to
379 * optimize for this case if this flag is set. (Note that there
380 * is also a promise, if the above case is true, not to signal
381 * overruns, either.)
382 *
383 * TTY_DRIVER_DYNAMIC_DEV --- if set, the individual tty devices need
384 * to be registered with a call to tty_register_device() when the
385 * device is found in the system and unregistered with a call to
386 * tty_unregister_device() so the devices will be show up
387 * properly in sysfs. If not set, driver->num entries will be
388 * created by the tty core in sysfs when tty_register_driver() is
389 * called. This is to be used by drivers that have tty devices
390 * that can appear and disappear while the main tty driver is
391 * registered with the tty core.
392 *
393 * TTY_DRIVER_DEVPTS_MEM -- don't use the standard arrays, instead
394 * use dynamic memory keyed through the devpts filesystem. This
395 * is only applicable to the pty driver.
396 *
397 * TTY_DRIVER_HARDWARE_BREAK -- hardware handles break signals. Pass
398 * the requested timeout to the caller instead of using a simple
399 * on/off interface.
400 *
401 * TTY_DRIVER_DYNAMIC_ALLOC -- do not allocate structures which are
402 * needed per line for this driver as it would waste memory.
403 * The driver will take care.
404 *
405 * TTY_DRIVER_UNNUMBERED_NODE -- do not create numbered /dev nodes. In
406 * other words create /dev/ttyprintk and not /dev/ttyprintk0.
407 * Applicable only when a driver for a single tty device is
408 * being allocated.
409 */
410 #define TTY_DRIVER_INSTALLED 0x0001
411 #define TTY_DRIVER_RESET_TERMIOS 0x0002
412 #define TTY_DRIVER_REAL_RAW 0x0004
413 #define TTY_DRIVER_DYNAMIC_DEV 0x0008
414 #define TTY_DRIVER_DEVPTS_MEM 0x0010
415 #define TTY_DRIVER_HARDWARE_BREAK 0x0020
416 #define TTY_DRIVER_DYNAMIC_ALLOC 0x0040
417 #define TTY_DRIVER_UNNUMBERED_NODE 0x0080
418
419 /* tty driver types */
420 #define TTY_DRIVER_TYPE_SYSTEM 0x0001
421 #define TTY_DRIVER_TYPE_CONSOLE 0x0002
422 #define TTY_DRIVER_TYPE_SERIAL 0x0003
423 #define TTY_DRIVER_TYPE_PTY 0x0004
424 #define TTY_DRIVER_TYPE_SCC 0x0005 /* scc driver */
425 #define TTY_DRIVER_TYPE_SYSCONS 0x0006
426
427 /* system subtypes (magic, used by tty_io.c) */
428 #define SYSTEM_TYPE_TTY 0x0001
429 #define SYSTEM_TYPE_CONSOLE 0x0002
430 #define SYSTEM_TYPE_SYSCONS 0x0003
431 #define SYSTEM_TYPE_SYSPTMX 0x0004
432
433 /* pty subtypes (magic, used by tty_io.c) */
434 #define PTY_TYPE_MASTER 0x0001
435 #define PTY_TYPE_SLAVE 0x0002
436
437 /* serial subtype definitions */
438 #define SERIAL_TYPE_NORMAL 1
439
440 #endif /* #ifdef _LINUX_TTY_DRIVER_H */
441