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