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8d29e002 JS |
1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _LINUX_TTY_BUFFER_H | |
3 | #define _LINUX_TTY_BUFFER_H | |
4 | ||
5 | #include <linux/atomic.h> | |
6 | #include <linux/llist.h> | |
7 | #include <linux/mutex.h> | |
8 | #include <linux/workqueue.h> | |
9 | ||
10 | struct tty_buffer { | |
11 | union { | |
12 | struct tty_buffer *next; | |
13 | struct llist_node free; | |
14 | }; | |
15 | int used; | |
16 | int size; | |
17 | int commit; | |
18 | int read; | |
19 | int flags; | |
20 | /* Data points here */ | |
21 | unsigned long data[]; | |
22 | }; | |
23 | ||
24 | /* Values for .flags field of tty_buffer */ | |
25 | #define TTYB_NORMAL 1 /* buffer has no flags buffer */ | |
26 | ||
27 | static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs) | |
28 | { | |
29 | return ((unsigned char *)b->data) + ofs; | |
30 | } | |
31 | ||
32 | static inline char *flag_buf_ptr(struct tty_buffer *b, int ofs) | |
33 | { | |
34 | return (char *)char_buf_ptr(b, ofs) + b->size; | |
35 | } | |
36 | ||
37 | struct tty_bufhead { | |
38 | struct tty_buffer *head; /* Queue head */ | |
39 | struct work_struct work; | |
40 | struct mutex lock; | |
41 | atomic_t priority; | |
42 | struct tty_buffer sentinel; | |
43 | struct llist_head free; /* Free queue head */ | |
44 | atomic_t mem_used; /* In-use buffers excluding free list */ | |
45 | int mem_limit; | |
46 | struct tty_buffer *tail; /* Active buffer */ | |
47 | }; | |
48 | ||
49 | /* | |
50 | * When a break, frame error, or parity error happens, these codes are | |
51 | * stuffed into the flags buffer. | |
52 | */ | |
53 | #define TTY_NORMAL 0 | |
54 | #define TTY_BREAK 1 | |
55 | #define TTY_FRAME 2 | |
56 | #define TTY_PARITY 3 | |
57 | #define TTY_OVERRUN 4 | |
58 | ||
59 | #endif |