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1da177e4 LT |
1 | #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 | * | |
62 | * void (*set_termios)(struct tty_struct *tty, struct termios * old); | |
63 | * | |
64 | * This function notifies the line discpline that a change has | |
65 | * been made to the termios structure. | |
66 | * | |
67 | * int (*poll)(struct tty_struct * tty, struct file * file, | |
68 | * poll_table *wait); | |
69 | * | |
70 | * This function is called when a user attempts to select/poll on a | |
71 | * tty device. It is solely the responsibility of the line | |
72 | * discipline to handle poll requests. | |
73 | * | |
74 | * void (*receive_buf)(struct tty_struct *, const unsigned char *cp, | |
75 | * char *fp, int count); | |
76 | * | |
77 | * This function is called by the low-level tty driver to send | |
78 | * characters received by the hardware to the line discpline for | |
79 | * processing. <cp> is a pointer to the buffer of input | |
80 | * character received by the device. <fp> is a pointer to a | |
81 | * pointer of flag bytes which indicate whether a character was | |
82 | * received with a parity error, etc. | |
83 | * | |
1da177e4 LT |
84 | * void (*write_wakeup)(struct tty_struct *); |
85 | * | |
86 | * This function is called by the low-level tty driver to signal | |
87 | * that line discpline should try to send more characters to the | |
88 | * low-level driver for transmission. If the line discpline does | |
89 | * not have any more data to send, it can just return. | |
90 | * | |
91 | * int (*hangup)(struct tty_struct *) | |
92 | * | |
93 | * Called on a hangup. Tells the discipline that it should | |
94 | * cease I/O to the tty driver. Can sleep. The driver should | |
95 | * seek to perform this action quickly but should wait until | |
96 | * any pending driver I/O is completed. | |
97 | */ | |
98 | ||
99 | #include <linux/fs.h> | |
100 | #include <linux/wait.h> | |
101 | ||
102 | struct tty_ldisc { | |
103 | int magic; | |
104 | char *name; | |
105 | int num; | |
106 | int flags; | |
107 | ||
108 | /* | |
109 | * The following routines are called from above. | |
110 | */ | |
111 | int (*open)(struct tty_struct *); | |
112 | void (*close)(struct tty_struct *); | |
113 | void (*flush_buffer)(struct tty_struct *tty); | |
114 | ssize_t (*chars_in_buffer)(struct tty_struct *tty); | |
115 | ssize_t (*read)(struct tty_struct * tty, struct file * file, | |
116 | unsigned char __user * buf, size_t nr); | |
117 | ssize_t (*write)(struct tty_struct * tty, struct file * file, | |
118 | const unsigned char * buf, size_t nr); | |
119 | int (*ioctl)(struct tty_struct * tty, struct file * file, | |
120 | unsigned int cmd, unsigned long arg); | |
121 | void (*set_termios)(struct tty_struct *tty, struct termios * old); | |
122 | unsigned int (*poll)(struct tty_struct *, struct file *, | |
123 | struct poll_table_struct *); | |
124 | int (*hangup)(struct tty_struct *tty); | |
125 | ||
126 | /* | |
127 | * The following routines are called from below. | |
128 | */ | |
129 | void (*receive_buf)(struct tty_struct *, const unsigned char *cp, | |
130 | char *fp, int count); | |
1da177e4 LT |
131 | void (*write_wakeup)(struct tty_struct *); |
132 | ||
133 | struct module *owner; | |
134 | ||
135 | int refcount; | |
136 | }; | |
137 | ||
138 | #define TTY_LDISC_MAGIC 0x5403 | |
139 | ||
140 | #define LDISC_FLAG_DEFINED 0x00000001 | |
141 | ||
142 | #define MODULE_ALIAS_LDISC(ldisc) \ | |
143 | MODULE_ALIAS("tty-ldisc-" __stringify(ldisc)) | |
144 | ||
145 | #endif /* _LINUX_TTY_LDISC_H */ |