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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _LINUX_TTY_LDISC_H
2#define _LINUX_TTY_LDISC_H
3
4/*
5 * This structure defines the interface between the tty line discipline
6 * implementation 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 * int (*open)(struct tty_struct *);
11 *
12 * This function is called when the line discipline is associated
13 * with the tty. The line discipline can use this as an
14 * opportunity to initialize any state needed by the ldisc routines.
15 *
16 * void (*close)(struct tty_struct *);
17 *
18 * This function is called when the line discipline is being
19 * shutdown, either because the tty is being closed or because
20 * the tty is being changed to use a new line discipline
21 *
22 * void (*flush_buffer)(struct tty_struct *tty);
23 *
24 * This function instructs the line discipline to clear its
25 * buffers of any input characters it may have queued to be
26 * delivered to the user mode process.
27 *
28 * ssize_t (*chars_in_buffer)(struct tty_struct *tty);
29 *
30 * This function returns the number of input characters the line
31 * discipline may have queued up to be delivered to the user mode
32 * process.
33 *
34 * ssize_t (*read)(struct tty_struct * tty, struct file * file,
35 * unsigned char * buf, size_t nr);
36 *
37 * This function is called when the user requests to read from
38 * the tty. The line discipline will return whatever characters
39 * it has buffered up for the user. If this function is not
40 * defined, the user will receive an EIO error.
41 *
42 * ssize_t (*write)(struct tty_struct * tty, struct file * file,
43 * const unsigned char * buf, size_t nr);
44 *
45 * This function is called when the user requests to write to the
46 * tty. The line discipline will deliver the characters to the
47 * low-level tty device for transmission, optionally performing
48 * some processing on the characters first. If this function is
49 * not defined, the user will receive an EIO error.
50 *
51 * int (*ioctl)(struct tty_struct * tty, struct file * file,
52 * unsigned int cmd, unsigned long arg);
53 *
54 * This function is called when the user requests an ioctl which
55 * is not handled by the tty layer or the low-level tty driver.
56 * It is intended for ioctls which affect line discpline
57 * operation. Note that the search order for ioctls is (1) tty
58 * layer, (2) tty low-level driver, (3) line discpline. So a
59 * low-level driver can "grab" an ioctl request before the line
60 * discpline has a chance to see it.
61 *
Paul Fulghume10cc1d2007-05-10 22:22:50 -070062 * long (*compat_ioctl)(struct tty_struct * tty, struct file * file,
63 * unsigned int cmd, unsigned long arg);
64 *
65 * Process ioctl calls from 32-bit process on 64-bit system
66 *
Alan Coxedc6afc2006-12-08 02:38:44 -080067 * void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
Linus Torvalds1da177e2005-04-16 15:20:36 -070068 *
69 * This function notifies the line discpline that a change has
70 * been made to the termios structure.
71 *
72 * int (*poll)(struct tty_struct * tty, struct file * file,
73 * poll_table *wait);
74 *
75 * This function is called when a user attempts to select/poll on a
76 * tty device. It is solely the responsibility of the line
77 * discipline to handle poll requests.
78 *
79 * void (*receive_buf)(struct tty_struct *, const unsigned char *cp,
80 * char *fp, int count);
81 *
82 * This function is called by the low-level tty driver to send
83 * characters received by the hardware to the line discpline for
84 * processing. <cp> is a pointer to the buffer of input
85 * character received by the device. <fp> is a pointer to a
86 * pointer of flag bytes which indicate whether a character was
87 * received with a parity error, etc.
88 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 * void (*write_wakeup)(struct tty_struct *);
90 *
91 * This function is called by the low-level tty driver to signal
92 * that line discpline should try to send more characters to the
93 * low-level driver for transmission. If the line discpline does
94 * not have any more data to send, it can just return.
95 *
96 * int (*hangup)(struct tty_struct *)
97 *
98 * Called on a hangup. Tells the discipline that it should
99 * cease I/O to the tty driver. Can sleep. The driver should
100 * seek to perform this action quickly but should wait until
101 * any pending driver I/O is completed.
102 */
103
104#include <linux/fs.h>
105#include <linux/wait.h>
106
107struct tty_ldisc {
108 int magic;
109 char *name;
110 int num;
111 int flags;
112
113 /*
114 * The following routines are called from above.
115 */
116 int (*open)(struct tty_struct *);
117 void (*close)(struct tty_struct *);
118 void (*flush_buffer)(struct tty_struct *tty);
119 ssize_t (*chars_in_buffer)(struct tty_struct *tty);
120 ssize_t (*read)(struct tty_struct * tty, struct file * file,
121 unsigned char __user * buf, size_t nr);
122 ssize_t (*write)(struct tty_struct * tty, struct file * file,
123 const unsigned char * buf, size_t nr);
124 int (*ioctl)(struct tty_struct * tty, struct file * file,
125 unsigned int cmd, unsigned long arg);
Paul Fulghume10cc1d2007-05-10 22:22:50 -0700126 long (*compat_ioctl)(struct tty_struct * tty, struct file * file,
127 unsigned int cmd, unsigned long arg);
Alan Coxedc6afc2006-12-08 02:38:44 -0800128 void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 unsigned int (*poll)(struct tty_struct *, struct file *,
130 struct poll_table_struct *);
131 int (*hangup)(struct tty_struct *tty);
132
133 /*
134 * The following routines are called from below.
135 */
136 void (*receive_buf)(struct tty_struct *, const unsigned char *cp,
137 char *fp, int count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 void (*write_wakeup)(struct tty_struct *);
139
140 struct module *owner;
141
142 int refcount;
143};
144
145#define TTY_LDISC_MAGIC 0x5403
146
147#define LDISC_FLAG_DEFINED 0x00000001
148
149#define MODULE_ALIAS_LDISC(ldisc) \
150 MODULE_ALIAS("tty-ldisc-" __stringify(ldisc))
151
152#endif /* _LINUX_TTY_LDISC_H */