| 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 lookahead; /* Lazy update on recv, can become less than "read" */ |
| 19 | int read; |
| 20 | bool flags; |
| 21 | /* Data points here */ |
| 22 | unsigned long data[]; |
| 23 | }; |
| 24 | |
| 25 | static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs) |
| 26 | { |
| 27 | return ((unsigned char *)b->data) + ofs; |
| 28 | } |
| 29 | |
| 30 | static inline char *flag_buf_ptr(struct tty_buffer *b, int ofs) |
| 31 | { |
| 32 | return (char *)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 |