tty_buffer.h (1308B)
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 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 27static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs) 28{ 29 return ((unsigned char *)b->data) + ofs; 30} 31 32static inline char *flag_buf_ptr(struct tty_buffer *b, int ofs) 33{ 34 return (char *)char_buf_ptr(b, ofs) + b->size; 35} 36 37struct 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