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