Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) #include <linux/types.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) #include <linux/errno.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) #include <linux/tty.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8)  *  n_null.c - Null line discipline used in the failure path
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10)  *  Copyright (C) Intel 2017
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) static int n_null_open(struct tty_struct *tty)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) static void n_null_close(struct tty_struct *tty)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) static ssize_t n_null_read(struct tty_struct *tty, struct file *file,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) 			   unsigned char *buf, size_t nr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) 			   void **cookie, unsigned long offset)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) 	return -EOPNOTSUPP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) static ssize_t n_null_write(struct tty_struct *tty, struct file *file,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 			    const unsigned char *buf, size_t nr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 	return -EOPNOTSUPP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) static void n_null_receivebuf(struct tty_struct *tty,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 				 const unsigned char *cp, char *fp,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 				 int cnt)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) static struct tty_ldisc_ops null_ldisc = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 	.owner		=	THIS_MODULE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 	.magic		=	TTY_LDISC_MAGIC,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 	.name		=	"n_null",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 	.open		=	n_null_open,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 	.close		=	n_null_close,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) 	.read		=	n_null_read,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) 	.write		=	n_null_write,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) 	.receive_buf	=	n_null_receivebuf
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) static int __init n_null_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) 	BUG_ON(tty_register_ldisc(N_NULL, &null_ldisc));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) static void __exit n_null_exit(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) 	tty_unregister_ldisc(N_NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) module_init(n_null_init);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) module_exit(n_null_exit);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) MODULE_LICENSE("GPL");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) MODULE_AUTHOR("Alan Cox");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) MODULE_ALIAS_LDISC(N_NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) MODULE_DESCRIPTION("Null ldisc driver");