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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef _LINUX_TTY_LDISC_H |
3 | #define _LINUX_TTY_LDISC_H | |
4 | ||
a24bc667 JS |
5 | struct tty_struct; |
6 | ||
1da177e4 LT |
7 | #include <linux/fs.h> |
8 | #include <linux/wait.h> | |
5fd691af | 9 | #include <linux/atomic.h> |
abca9901 JS |
10 | #include <linux/list.h> |
11 | #include <linux/lockdep.h> | |
a24bc667 | 12 | #include <linux/seq_file.h> |
4898e640 PH |
13 | |
14 | /* | |
15 | * the semaphore definition | |
16 | */ | |
17 | struct ld_semaphore { | |
5fd691af | 18 | atomic_long_t count; |
4898e640 PH |
19 | raw_spinlock_t wait_lock; |
20 | unsigned int wait_readers; | |
21 | struct list_head read_wait; | |
22 | struct list_head write_wait; | |
23 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
24 | struct lockdep_map dep_map; | |
25 | #endif | |
26 | }; | |
27 | ||
78941934 | 28 | void __init_ldsem(struct ld_semaphore *sem, const char *name, |
4898e640 PH |
29 | struct lock_class_key *key); |
30 | ||
31 | #define init_ldsem(sem) \ | |
32 | do { \ | |
33 | static struct lock_class_key __key; \ | |
34 | \ | |
35 | __init_ldsem((sem), #sem, &__key); \ | |
36 | } while (0) | |
37 | ||
38 | ||
78941934 JS |
39 | int ldsem_down_read(struct ld_semaphore *sem, long timeout); |
40 | int ldsem_down_read_trylock(struct ld_semaphore *sem); | |
41 | int ldsem_down_write(struct ld_semaphore *sem, long timeout); | |
42 | int ldsem_down_write_trylock(struct ld_semaphore *sem); | |
43 | void ldsem_up_read(struct ld_semaphore *sem); | |
44 | void ldsem_up_write(struct ld_semaphore *sem); | |
4898e640 PH |
45 | |
46 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
78941934 JS |
47 | int ldsem_down_read_nested(struct ld_semaphore *sem, int subclass, |
48 | long timeout); | |
49 | int ldsem_down_write_nested(struct ld_semaphore *sem, int subclass, | |
50 | long timeout); | |
4898e640 PH |
51 | #else |
52 | # define ldsem_down_read_nested(sem, subclass, timeout) \ | |
53 | ldsem_down_read(sem, timeout) | |
54 | # define ldsem_down_write_nested(sem, subclass, timeout) \ | |
55 | ldsem_down_write(sem, timeout) | |
56 | #endif | |
57 | ||
0c6119f9 JS |
58 | /** |
59 | * struct tty_ldisc_ops - ldisc operations | |
60 | * | |
61 | * @name: name of this ldisc rendered in /proc/tty/ldiscs | |
62 | * @num: ``N_*`` number (%N_TTY, %N_HDLC, ...) reserved to this ldisc | |
63 | * | |
64 | * @open: ``int ()(struct tty_struct *tty)`` | |
65 | * | |
66 | * This function is called when the line discipline is associated with the | |
67 | * @tty. The line discipline can use this as an opportunity to initialize | |
68 | * any state needed by the ldisc routines. | |
69 | * | |
70 | * @close: ``void ()(struct tty_struct *tty)`` | |
71 | * | |
72 | * This function is called when the line discipline is being shutdown, | |
73 | * either because the @tty is being closed or because the @tty is being | |
74 | * changed to use a new line discipline | |
75 | * | |
76 | * @flush_buffer: ``void ()(struct tty_struct *tty)`` | |
77 | * | |
78 | * This function instructs the line discipline to clear its buffers of any | |
79 | * input characters it may have queued to be delivered to the user mode | |
80 | * process. | |
81 | * | |
82 | * @read: ``ssize_t ()(struct tty_struct *tty, struct file *file, | |
83 | * unsigned char *buf, size_t nr)`` | |
84 | * | |
85 | * This function is called when the user requests to read from the @tty. | |
86 | * The line discipline will return whatever characters it has buffered up | |
87 | * for the user. If this function is not defined, the user will receive | |
88 | * an %EIO error. | |
89 | * | |
90 | * @write: ``ssize_t ()(struct tty_struct *tty, struct file *file, | |
91 | * const unsigned char *buf, size_t nr)`` | |
92 | * | |
93 | * This function is called when the user requests to write to the @tty. | |
94 | * The line discipline will deliver the characters to the low-level tty | |
95 | * device for transmission, optionally performing some processing on the | |
96 | * characters first. If this function is not defined, the user will | |
97 | * receive an %EIO error. | |
98 | * | |
99 | * @ioctl: ``int ()(struct tty_struct *tty, unsigned int cmd, | |
100 | * unsigned long arg)`` | |
101 | * | |
102 | * This function is called when the user requests an ioctl which is not | |
103 | * handled by the tty layer or the low-level tty driver. It is intended | |
104 | * for ioctls which affect line discpline operation. Note that the search | |
105 | * order for ioctls is (1) tty layer, (2) tty low-level driver, (3) line | |
106 | * discpline. So a low-level driver can "grab" an ioctl request before | |
107 | * the line discpline has a chance to see it. | |
108 | * | |
109 | * @compat_ioctl: ``int ()(struct tty_struct *tty, unsigned int cmd, | |
110 | * unsigned long arg)`` | |
111 | * | |
112 | * Process ioctl calls from 32-bit process on 64-bit system. | |
113 | * | |
114 | * Note that only ioctls that are neither "pointer to compatible | |
115 | * structure" nor tty-generic. Something private that takes an integer or | |
116 | * a pointer to wordsize-sensitive structure belongs here, but most of | |
117 | * ldiscs will happily leave it %NULL. | |
118 | * | |
119 | * @set_termios: ``void ()(struct tty_struct *tty, struct ktermios *old)`` | |
120 | * | |
121 | * This function notifies the line discpline that a change has been made | |
122 | * to the termios structure. | |
123 | * | |
124 | * @poll: ``int ()(struct tty_struct *tty, struct file *file, | |
125 | * struct poll_table_struct *wait)`` | |
126 | * | |
127 | * This function is called when a user attempts to select/poll on a @tty | |
128 | * device. It is solely the responsibility of the line discipline to | |
129 | * handle poll requests. | |
130 | * | |
131 | * @hangup: ``void ()(struct tty_struct *tty)`` | |
132 | * | |
133 | * Called on a hangup. Tells the discipline that it should cease I/O to | |
134 | * the tty driver. Can sleep. The driver should seek to perform this | |
135 | * action quickly but should wait until any pending driver I/O is | |
136 | * completed. | |
137 | * | |
138 | * @receive_buf: ``void ()(struct tty_struct *tty, const unsigned char *cp, | |
139 | * const char *fp, int count)`` | |
140 | * | |
141 | * This function is called by the low-level tty driver to send characters | |
142 | * received by the hardware to the line discpline for processing. @cp is | |
143 | * a pointer to the buffer of input character received by the device. @fp | |
144 | * is a pointer to an array of flag bytes which indicate whether a | |
145 | * character was received with a parity error, etc. @fp may be %NULL to | |
146 | * indicate all data received is %TTY_NORMAL. | |
147 | * | |
148 | * @write_wakeup: ``void ()(struct tty_struct *tty)`` | |
149 | * | |
150 | * This function is called by the low-level tty driver to signal that line | |
151 | * discpline should try to send more characters to the low-level driver | |
152 | * for transmission. If the line discpline does not have any more data to | |
153 | * send, it can just return. If the line discipline does have some data to | |
154 | * send, please arise a tasklet or workqueue to do the real data transfer. | |
155 | * Do not send data in this hook, it may lead to a deadlock. | |
156 | * | |
157 | * @dcd_change: ``void ()(struct tty_struct *tty, unsigned int status)`` | |
158 | * | |
159 | * Tells the discipline that the DCD pin has changed its status. Used | |
160 | * exclusively by the %N_PPS (Pulse-Per-Second) line discipline. | |
161 | * | |
162 | * @receive_buf2: ``int ()(struct tty_struct *tty, const unsigned char *cp, | |
163 | * const char *fp, int count)`` | |
164 | * | |
165 | * This function is called by the low-level tty driver to send characters | |
166 | * received by the hardware to the line discpline for processing. @cp is a | |
167 | * pointer to the buffer of input character received by the device. @fp | |
168 | * is a pointer to an array of flag bytes which indicate whether a | |
169 | * character was received with a parity error, etc. @fp may be %NULL to | |
170 | * indicate all data received is %TTY_NORMAL. If assigned, prefer this | |
171 | * function for automatic flow control. | |
172 | * | |
173 | * @owner: module containting this ldisc (for reference counting) | |
174 | * | |
175 | * This structure defines the interface between the tty line discipline | |
176 | * implementation and the tty routines. The above routines can be defined. | |
177 | * Unless noted otherwise, they are optional, and can be filled in with a %NULL | |
178 | * pointer. | |
179 | */ | |
a352def2 | 180 | struct tty_ldisc_ops { |
1da177e4 LT |
181 | char *name; |
182 | int num; | |
6be06e72 | 183 | |
1da177e4 LT |
184 | /* |
185 | * The following routines are called from above. | |
186 | */ | |
0c6119f9 JS |
187 | int (*open)(struct tty_struct *tty); |
188 | void (*close)(struct tty_struct *tty); | |
1da177e4 | 189 | void (*flush_buffer)(struct tty_struct *tty); |
6be06e72 | 190 | ssize_t (*read)(struct tty_struct *tty, struct file *file, |
3b830a9c LT |
191 | unsigned char *buf, size_t nr, |
192 | void **cookie, unsigned long offset); | |
6be06e72 PH |
193 | ssize_t (*write)(struct tty_struct *tty, struct file *file, |
194 | const unsigned char *buf, size_t nr); | |
d78328bc JS |
195 | int (*ioctl)(struct tty_struct *tty, unsigned int cmd, |
196 | unsigned long arg); | |
197 | int (*compat_ioctl)(struct tty_struct *tty, unsigned int cmd, | |
198 | unsigned long arg); | |
6be06e72 | 199 | void (*set_termios)(struct tty_struct *tty, struct ktermios *old); |
0c6119f9 JS |
200 | __poll_t (*poll)(struct tty_struct *tty, struct file *file, |
201 | struct poll_table_struct *wait); | |
28f194da | 202 | void (*hangup)(struct tty_struct *tty); |
6be06e72 | 203 | |
1da177e4 LT |
204 | /* |
205 | * The following routines are called from below. | |
206 | */ | |
0c6119f9 | 207 | void (*receive_buf)(struct tty_struct *tty, const unsigned char *cp, |
0f3dcf3b | 208 | const char *fp, int count); |
0c6119f9 JS |
209 | void (*write_wakeup)(struct tty_struct *tty); |
210 | void (*dcd_change)(struct tty_struct *tty, unsigned int status); | |
211 | int (*receive_buf2)(struct tty_struct *tty, const unsigned char *cp, | |
0f3dcf3b | 212 | const char *fp, int count); |
1da177e4 LT |
213 | |
214 | struct module *owner; | |
1da177e4 LT |
215 | }; |
216 | ||
a352def2 AC |
217 | struct tty_ldisc { |
218 | struct tty_ldisc_ops *ops; | |
36697529 | 219 | struct tty_struct *tty; |
a352def2 AC |
220 | }; |
221 | ||
1da177e4 LT |
222 | #define MODULE_ALIAS_LDISC(ldisc) \ |
223 | MODULE_ALIAS("tty-ldisc-" __stringify(ldisc)) | |
224 | ||
a24bc667 JS |
225 | extern const struct seq_operations tty_ldiscs_seq_ops; |
226 | ||
227 | struct tty_ldisc *tty_ldisc_ref(struct tty_struct *); | |
228 | void tty_ldisc_deref(struct tty_ldisc *); | |
229 | struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *); | |
230 | ||
231 | void tty_ldisc_flush(struct tty_struct *tty); | |
232 | ||
233 | int tty_register_ldisc(struct tty_ldisc_ops *new_ldisc); | |
234 | void tty_unregister_ldisc(struct tty_ldisc_ops *ldisc); | |
235 | int tty_set_ldisc(struct tty_struct *tty, int disc); | |
236 | ||
1da177e4 | 237 | #endif /* _LINUX_TTY_LDISC_H */ |