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/*
* 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);
spin_lock_init(&port->lock);
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);
/**
* tty_port_tty_get - get a tty reference
* @port: tty port
*
* Return a refcount protected tty instance or NULL if the port is not
* associated with a tty (eg due to close or hangup)
*/
struct tty_struct *tty_port_tty_get(struct tty_port *port)
{
unsigned long flags;
struct tty_struct *tty;
spin_lock_irqsave(&port->lock, flags);
tty = tty_kref_get(port->tty);
spin_unlock_irqrestore(&port->lock, flags);
return tty;
}
EXPORT_SYMBOL(tty_port_tty_get);
/**
* tty_port_tty_set - set the tty of a port
* @port: tty port
* @tty: the tty
*
* Associate the port and tty pair. Manages any internal refcounts.
* Pass NULL to deassociate a port
*/
void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty)
{
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
if (port->tty)
tty_kref_put(port->tty);
port->tty = tty_kref_get(tty);
spin_unlock_irqrestore(&port->lock, flags);
}
EXPORT_SYMBOL(tty_port_tty_set);
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