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 | unsigned int used; |
16 | unsigned int size; |
17 | unsigned int commit; |
18 | unsigned int lookahead; /* Lazy update on recv, can become less than "read" */ |
19 | unsigned int read; |
20 | bool flags; |
21 | /* Data points here */ |
22 | u8 data[] __aligned(sizeof(unsigned long)); |
23 | }; |
24 | |
25 | static inline u8 *char_buf_ptr(struct tty_buffer *b, unsigned int ofs) |
26 | { |
27 | return b->data + ofs; |
28 | } |
29 | |
30 | static inline u8 *flag_buf_ptr(struct tty_buffer *b, unsigned int ofs) |
31 | { |
32 | return char_buf_ptr(b, ofs) + b->size; |
33 | } |
34 | |
35 | struct tty_bufhead { |
36 | struct tty_buffer *head; /* Queue head */ |
37 | struct work_struct work; |
38 | struct mutex lock; |
39 | atomic_t priority; |
40 | struct tty_buffer sentinel; |
41 | struct llist_head free; /* Free queue head */ |
42 | atomic_t mem_used; /* In-use buffers excluding free list */ |
43 | int mem_limit; |
44 | struct tty_buffer *tail; /* Active buffer */ |
45 | }; |
46 | |
47 | /* |
48 | * When a break, frame error, or parity error happens, these codes are |
49 | * stuffed into the flags buffer. |
50 | */ |
51 | #define TTY_NORMAL 0 |
52 | #define TTY_BREAK 1 |
53 | #define TTY_FRAME 2 |
54 | #define TTY_PARITY 3 |
55 | #define TTY_OVERRUN 4 |
56 | |
57 | #endif |
58 | |