summaryrefslogtreecommitdiff
path: root/drivers/char/tty_port.c
blob: 6fadb19d630b0ab6d749a033fab2e39c26457841 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
/*
 * Tty port functions
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/module.h>

void tty_port_init(struct tty_port *port)
{
	memset(port, 0, sizeof(*port));
	init_waitqueue_head(&port->open_wait);
	init_waitqueue_head(&port->close_wait);
	mutex_init(&port->mutex);
	port->close_delay = (50 * HZ) / 100;
	port->closing_wait = (3000 * HZ) / 100;
}
EXPORT_SYMBOL(tty_port_init);

int tty_port_alloc_xmit_buf(struct tty_port *port)
{
	/* We may sleep in get_zeroed_page() */
	mutex_lock(&port->mutex);
	if (port->xmit_buf == NULL)
		port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL);
	mutex_unlock(&port->mutex);
	if (port->xmit_buf == NULL)
		return -ENOMEM;
	return 0;
}
EXPORT_SYMBOL(tty_port_alloc_xmit_buf);

void tty_port_free_xmit_buf(struct tty_port *port)
{
	mutex_lock(&port->mutex);
	if (port->xmit_buf != NULL) {
		free_page((unsigned long)port->xmit_buf);
		port->xmit_buf = NULL;
	}
	mutex_unlock(&port->mutex);
}
EXPORT_SYMBOL(tty_port_free_xmit_buf);