v4.19.13 snapshot.
diff --git a/arch/um/drivers/line.h b/arch/um/drivers/line.h
new file mode 100644
index 0000000..138a145
--- /dev/null
+++ b/arch/um/drivers/line.h
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#ifndef __LINE_H__
+#define __LINE_H__
+
+#include <linux/list.h>
+#include <linux/workqueue.h>
+#include <linux/tty.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include "chan_user.h"
+#include "mconsole_kern.h"
+
+/* There's only two modifiable fields in this - .mc.list and .driver */
+struct line_driver {
+ const char *name;
+ const char *device_name;
+ const short major;
+ const short minor_start;
+ const short type;
+ const short subtype;
+ const int read_irq;
+ const char *read_irq_name;
+ const int write_irq;
+ const char *write_irq_name;
+ struct mc_device mc;
+ struct tty_driver *driver;
+};
+
+struct line {
+ struct tty_port port;
+ int valid;
+
+ char *init_str;
+ struct list_head chan_list;
+ struct chan *chan_in, *chan_out;
+
+ /*This lock is actually, mostly, local to*/
+ spinlock_t lock;
+ int throttled;
+ /* Yes, this is a real circular buffer.
+ * XXX: And this should become a struct kfifo!
+ *
+ * buffer points to a buffer allocated on demand, of length
+ * LINE_BUFSIZE, head to the start of the ring, tail to the end.*/
+ char *buffer;
+ char *head;
+ char *tail;
+
+ int sigio;
+ struct delayed_work task;
+ const struct line_driver *driver;
+};
+
+extern void line_close(struct tty_struct *tty, struct file * filp);
+extern int line_open(struct tty_struct *tty, struct file *filp);
+extern int line_install(struct tty_driver *driver, struct tty_struct *tty,
+ struct line *line);
+extern void line_cleanup(struct tty_struct *tty);
+extern void line_hangup(struct tty_struct *tty);
+extern int line_setup(char **conf, unsigned nlines, char **def,
+ char *init, char *name);
+extern int line_write(struct tty_struct *tty, const unsigned char *buf,
+ int len);
+extern int line_put_char(struct tty_struct *tty, unsigned char ch);
+extern void line_set_termios(struct tty_struct *tty, struct ktermios * old);
+extern int line_chars_in_buffer(struct tty_struct *tty);
+extern void line_flush_buffer(struct tty_struct *tty);
+extern void line_flush_chars(struct tty_struct *tty);
+extern int line_write_room(struct tty_struct *tty);
+extern void line_throttle(struct tty_struct *tty);
+extern void line_unthrottle(struct tty_struct *tty);
+
+extern char *add_xterm_umid(char *base);
+extern int line_setup_irq(int fd, int input, int output, struct line *line,
+ void *data);
+extern void line_close_chan(struct line *line);
+extern int register_lines(struct line_driver *line_driver,
+ const struct tty_operations *driver,
+ struct line *lines, int nlines);
+extern int setup_one_line(struct line *lines, int n, char *init,
+ const struct chan_opts *opts, char **error_out);
+extern void close_lines(struct line *lines, int nlines);
+
+extern int line_config(struct line *lines, unsigned int sizeof_lines,
+ char *str, const struct chan_opts *opts,
+ char **error_out);
+extern int line_id(char **str, int *start_out, int *end_out);
+extern int line_remove(struct line *lines, unsigned int sizeof_lines, int n,
+ char **error_out);
+extern int line_get_config(char *dev, struct line *lines,
+ unsigned int sizeof_lines, char *str,
+ int size, char **error_out);
+
+#endif