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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 | * | |
6be06e72 PH |
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 | * | |
1da177e4 LT |
16 | * void (*close)(struct tty_struct *); |
17 | * | |
18 | * This function is called when the line discipline is being | |
6be06e72 PH |
19 | * shutdown, either because the tty is being closed or because |
20 | * the tty is being changed to use a new line discipline | |
21 | * | |
1da177e4 LT |
22 | * void (*flush_buffer)(struct tty_struct *tty); |
23 | * | |
6be06e72 PH |
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 | * | |
1da177e4 LT |
28 | * ssize_t (*chars_in_buffer)(struct tty_struct *tty); |
29 | * | |
6be06e72 | 30 | * This function returns the number of input characters the line |
1da177e4 LT |
31 | * discipline may have queued up to be delivered to the user mode |
32 | * process. | |
6be06e72 | 33 | * |
1da177e4 LT |
34 | * ssize_t (*read)(struct tty_struct * tty, struct file * file, |
35 | * unsigned char * buf, size_t nr); | |
36 | * | |
6be06e72 PH |
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 | * | |
1da177e4 | 42 | * ssize_t (*write)(struct tty_struct * tty, struct file * file, |
6be06e72 PH |
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 | * | |
1da177e4 | 51 | * int (*ioctl)(struct tty_struct * tty, struct file * file, |
6be06e72 | 52 | * unsigned int cmd, unsigned long arg); |
1da177e4 LT |
53 | * |
54 | * This function is called when the user requests an ioctl which | |
6be06e72 PH |
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 | * | |
e10cc1df | 62 | * long (*compat_ioctl)(struct tty_struct * tty, struct file * file, |
6be06e72 | 63 | * unsigned int cmd, unsigned long arg); |
e10cc1df | 64 | * |
6be06e72 | 65 | * Process ioctl calls from 32-bit process on 64-bit system |
e10cc1df | 66 | * |
edc6afc5 | 67 | * void (*set_termios)(struct tty_struct *tty, struct ktermios * old); |
1da177e4 | 68 | * |
6be06e72 PH |
69 | * This function notifies the line discpline that a change has |
70 | * been made to the termios structure. | |
71 | * | |
1da177e4 | 72 | * int (*poll)(struct tty_struct * tty, struct file * file, |
6be06e72 | 73 | * poll_table *wait); |
1da177e4 | 74 | * |
6be06e72 PH |
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. | |
1da177e4 | 78 | * |
55db4c64 | 79 | * void (*receive_buf)(struct tty_struct *, const unsigned char *cp, |
6be06e72 PH |
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 | |
82f91fe0 PH |
87 | * received with a parity error, etc. <fp> may be NULL to indicate |
88 | * all data received is TTY_NORMAL. | |
6be06e72 | 89 | * |
1da177e4 LT |
90 | * void (*write_wakeup)(struct tty_struct *); |
91 | * | |
6be06e72 PH |
92 | * This function is called by the low-level tty driver to signal |
93 | * that line discpline should try to send more characters to the | |
94 | * low-level driver for transmission. If the line discpline does | |
879eb9c3 HS |
95 | * not have any more data to send, it can just return. If the line |
96 | * discipline does have some data to send, please arise a tasklet | |
97 | * or workqueue to do the real data transfer. Do not send data in | |
98 | * this hook, it may leads to a deadlock. | |
1da177e4 LT |
99 | * |
100 | * int (*hangup)(struct tty_struct *) | |
101 | * | |
102 | * Called on a hangup. Tells the discipline that it should | |
103 | * cease I/O to the tty driver. Can sleep. The driver should | |
104 | * seek to perform this action quickly but should wait until | |
105 | * any pending driver I/O is completed. | |
b3e63afe | 106 | * |
f6c8dbe6 PH |
107 | * void (*fasync)(struct tty_struct *, int on) |
108 | * | |
109 | * Notify line discipline when signal-driven I/O is enabled or | |
110 | * disabled. | |
111 | * | |
593fb1ae | 112 | * void (*dcd_change)(struct tty_struct *tty, unsigned int status) |
b3e63afe | 113 | * |
593fb1ae GS |
114 | * Tells the discipline that the DCD pin has changed its status. |
115 | * Used exclusively by the N_PPS (Pulse-Per-Second) line discipline. | |
24a89d1c PH |
116 | * |
117 | * int (*receive_buf2)(struct tty_struct *, const unsigned char *cp, | |
118 | * char *fp, int count); | |
119 | * | |
120 | * This function is called by the low-level tty driver to send | |
121 | * characters received by the hardware to the line discpline for | |
122 | * processing. <cp> is a pointer to the buffer of input | |
123 | * character received by the device. <fp> is a pointer to a | |
124 | * pointer of flag bytes which indicate whether a character was | |
82f91fe0 PH |
125 | * received with a parity error, etc. <fp> may be NULL to indicate |
126 | * all data received is TTY_NORMAL. | |
24a89d1c | 127 | * If assigned, prefer this function for automatic flow control. |
1da177e4 LT |
128 | */ |
129 | ||
130 | #include <linux/fs.h> | |
131 | #include <linux/wait.h> | |
132 | ||
4898e640 PH |
133 | |
134 | /* | |
135 | * the semaphore definition | |
136 | */ | |
137 | struct ld_semaphore { | |
138 | long count; | |
139 | raw_spinlock_t wait_lock; | |
140 | unsigned int wait_readers; | |
141 | struct list_head read_wait; | |
142 | struct list_head write_wait; | |
143 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
144 | struct lockdep_map dep_map; | |
145 | #endif | |
146 | }; | |
147 | ||
148 | extern void __init_ldsem(struct ld_semaphore *sem, const char *name, | |
149 | struct lock_class_key *key); | |
150 | ||
151 | #define init_ldsem(sem) \ | |
152 | do { \ | |
153 | static struct lock_class_key __key; \ | |
154 | \ | |
155 | __init_ldsem((sem), #sem, &__key); \ | |
156 | } while (0) | |
157 | ||
158 | ||
159 | extern int ldsem_down_read(struct ld_semaphore *sem, long timeout); | |
160 | extern int ldsem_down_read_trylock(struct ld_semaphore *sem); | |
161 | extern int ldsem_down_write(struct ld_semaphore *sem, long timeout); | |
162 | extern int ldsem_down_write_trylock(struct ld_semaphore *sem); | |
163 | extern void ldsem_up_read(struct ld_semaphore *sem); | |
164 | extern void ldsem_up_write(struct ld_semaphore *sem); | |
165 | ||
166 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
167 | extern int ldsem_down_read_nested(struct ld_semaphore *sem, int subclass, | |
168 | long timeout); | |
169 | extern int ldsem_down_write_nested(struct ld_semaphore *sem, int subclass, | |
170 | long timeout); | |
171 | #else | |
172 | # define ldsem_down_read_nested(sem, subclass, timeout) \ | |
173 | ldsem_down_read(sem, timeout) | |
174 | # define ldsem_down_write_nested(sem, subclass, timeout) \ | |
175 | ldsem_down_write(sem, timeout) | |
176 | #endif | |
177 | ||
178 | ||
a352def2 | 179 | struct tty_ldisc_ops { |
1da177e4 LT |
180 | int magic; |
181 | char *name; | |
182 | int num; | |
183 | int flags; | |
6be06e72 | 184 | |
1da177e4 LT |
185 | /* |
186 | * The following routines are called from above. | |
187 | */ | |
188 | int (*open)(struct tty_struct *); | |
189 | void (*close)(struct tty_struct *); | |
190 | void (*flush_buffer)(struct tty_struct *tty); | |
191 | ssize_t (*chars_in_buffer)(struct tty_struct *tty); | |
6be06e72 PH |
192 | ssize_t (*read)(struct tty_struct *tty, struct file *file, |
193 | unsigned char __user *buf, size_t nr); | |
194 | ssize_t (*write)(struct tty_struct *tty, struct file *file, | |
195 | const unsigned char *buf, size_t nr); | |
196 | int (*ioctl)(struct tty_struct *tty, struct file *file, | |
1da177e4 | 197 | unsigned int cmd, unsigned long arg); |
6be06e72 | 198 | long (*compat_ioctl)(struct tty_struct *tty, struct file *file, |
e10cc1df | 199 | unsigned int cmd, unsigned long arg); |
6be06e72 | 200 | void (*set_termios)(struct tty_struct *tty, struct ktermios *old); |
1da177e4 LT |
201 | unsigned int (*poll)(struct tty_struct *, struct file *, |
202 | struct poll_table_struct *); | |
203 | int (*hangup)(struct tty_struct *tty); | |
6be06e72 | 204 | |
1da177e4 LT |
205 | /* |
206 | * The following routines are called from below. | |
207 | */ | |
55db4c64 LT |
208 | void (*receive_buf)(struct tty_struct *, const unsigned char *cp, |
209 | char *fp, int count); | |
1da177e4 | 210 | void (*write_wakeup)(struct tty_struct *); |
593fb1ae | 211 | void (*dcd_change)(struct tty_struct *, unsigned int); |
f6c8dbe6 | 212 | void (*fasync)(struct tty_struct *tty, int on); |
24a89d1c PH |
213 | int (*receive_buf2)(struct tty_struct *, const unsigned char *cp, |
214 | char *fp, int count); | |
1da177e4 LT |
215 | |
216 | struct module *owner; | |
6be06e72 | 217 | |
1da177e4 LT |
218 | int refcount; |
219 | }; | |
220 | ||
a352def2 AC |
221 | struct tty_ldisc { |
222 | struct tty_ldisc_ops *ops; | |
36697529 | 223 | struct tty_struct *tty; |
a352def2 AC |
224 | }; |
225 | ||
1da177e4 LT |
226 | #define TTY_LDISC_MAGIC 0x5403 |
227 | ||
228 | #define LDISC_FLAG_DEFINED 0x00000001 | |
229 | ||
230 | #define MODULE_ALIAS_LDISC(ldisc) \ | |
231 | MODULE_ALIAS("tty-ldisc-" __stringify(ldisc)) | |
232 | ||
233 | #endif /* _LINUX_TTY_LDISC_H */ |