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