Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
10struct 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
25static inline u8 *char_buf_ptr(struct tty_buffer *b, unsigned int ofs)
26{
27 return b->data + ofs;
28}
29
30static inline u8 *flag_buf_ptr(struct tty_buffer *b, unsigned int ofs)
31{
32 return char_buf_ptr(b, ofs) + b->size;
33}
34
35struct tty_bufhead {
36 struct tty_buffer *head; /* Queue head */
37 struct workqueue_struct *flip_wq;
38 struct work_struct work;
39 struct mutex lock;
40 atomic_t priority;
41 struct tty_buffer sentinel;
42 struct llist_head free; /* Free queue head */
43 atomic_t mem_used; /* In-use buffers excluding free list */
44 int mem_limit;
45 struct tty_buffer *tail; /* Active buffer */
46};
47
48/*
49 * When a break, frame error, or parity error happens, these codes are
50 * stuffed into the flags buffer.
51 */
52#define TTY_NORMAL 0
53#define TTY_BREAK 1
54#define TTY_FRAME 2
55#define TTY_PARITY 3
56#define TTY_OVERRUN 4
57
58#endif