/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_TTY_BUFFER_H #define _LINUX_TTY_BUFFER_H #include <linux/atomic.h> #include <linux/llist.h> #include <linux/mutex.h> #include <linux/workqueue.h> struct tty_buffer { union { struct tty_buffer *next; struct llist_node free; }; int used; int size; int commit; int lookahead; /* Lazy update on recv, can become less than "read" */ int read; int flags; /* Data points here */ unsigned long data[]; }; /* Values for .flags field of tty_buffer */ #define TTYB_NORMAL 1 /* buffer has no flags buffer */ static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs) { return ((unsigned char *)b->data) + ofs; } static inline char *flag_buf_ptr(struct tty_buffer *b, int ofs) { return (char *)char_buf_ptr(b, ofs) + b->size; } struct tty_bufhead { struct tty_buffer *head; /* Queue head */ struct work_struct work; struct mutex lock; atomic_t priority; struct tty_buffer sentinel; struct llist_head free; /* Free queue head */ atomic_t mem_used; /* In-use buffers excluding free list */ int mem_limit; struct tty_buffer *tail; /* Active buffer */ }; /* * When a break, frame error, or parity error happens, these codes are * stuffed into the flags buffer. */ #define TTY_NORMAL 0 #define TTY_BREAK 1 #define TTY_FRAME 2 #define TTY_PARITY 3 #define TTY_OVERRUN 4 #endif