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/*
* $Id: serport.c,v 1.4 2000/05/29 10:54:53 vojtech Exp $
*
* Copyright (c) 1999-2000 Vojtech Pavlik
*
* Sponsored by SuSE
*/
/*
* This is a module that converts a tty line into a much simpler
* 'serial io port' abstraction that the input device drivers use.
*/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Should you need to contact me, the author, you can do so either by
* e-mail - mail your message to <vojtech@ucw.cz>, or by paper mail:
* Vojtech Pavlik, Ucitelska 1576, Prague 8, 182 00 Czech Republic
*/
#include <asm/uaccess.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/serio.h>
#include <linux/tty.h>
struct serport {
struct tty_struct *tty;
wait_queue_head_t wait;
struct serio serio;
};
/*
* Callback functions from the serio code.
*/
static int serport_serio_write(struct serio *serio, unsigned char data)
{
struct serport *serport = serio->driver;
return -(serport->tty->driver.write(serport->tty, 0, &data, 1) != 1);
}
static int serport_serio_open(struct serio *serio)
{
return 0;
}
static void serport_serio_close(struct serio *serio)
{
struct serport *serport = serio->driver;
wake_up_interruptible(&serport->wait);
}
/*
* serport_ldisc_open() is the routine that is called upon setting our line
* discipline on a tty. It looks for the Mag, and if found, registers
* it as a joystick device.
*/
static int serport_ldisc_open(struct tty_struct *tty)
{
struct serport *serport;
MOD_INC_USE_COUNT;
if (!(serport = kmalloc(sizeof(struct serport), GFP_KERNEL))) {
MOD_DEC_USE_COUNT;
return -ENOMEM;
}
memset(serport, 0, sizeof(struct serport));
serport->tty = tty;
tty->disc_data = serport;
serport->serio.type = SERIO_RS232;
serport->serio.write = serport_serio_write;
serport->serio.open = serport_serio_open;
serport->serio.close = serport_serio_close;
serport->serio.driver = serport;
init_waitqueue_head(&serport->wait);
return 0;
}
/*
* serport_ldisc_close() is the opposite of serport_ldisc_open()
*/
static void serport_ldisc_close(struct tty_struct *tty)
{
struct serport *serport = (struct serport*) tty->disc_data;
kfree(serport);
MOD_DEC_USE_COUNT;
}
/*
* serport_ldisc_receive() is called by the low level tty driver when characters
* are ready for us. We forward the characters, one by one to the 'interrupt'
* routine.
*/
static void serport_ldisc_receive(struct tty_struct *tty, const unsigned char *cp, char *fp, int count)
{
struct serport *serport = (struct serport*) tty->disc_data;
int i;
for (i = 0; i < count; i++)
if (serport->serio.dev)
serport->serio.dev->interrupt(&serport->serio, cp[i], 0);
}
/*
* serport_ldisc_room() reports how much room we do have for receiving data.
* Although we in fact have infinite room, we need to specify some value
* here, and 256 seems to be reasonable.
*/
static int serport_ldisc_room(struct tty_struct *tty)
{
return 256;
}
/*
* serport_ldisc_read() just waits indefinitely if everything goes well.
* However, when the serio driver closes the serio port, it finishes,
* returning 0 characters.
*/
static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file, unsigned char * buf, size_t nr)
{
struct serport *serport = (struct serport*) tty->disc_data;
DECLARE_WAITQUEUE(wait, current);
char name[32];
sprintf(name, tty->driver.name, MINOR(tty->device) - tty->driver.minor_start);
serio_register_port(&serport->serio);
printk(KERN_INFO "serio%d: Serial port %s\n", serport->serio.number, name);
add_wait_queue(&serport->wait, &wait);
current->state = TASK_INTERRUPTIBLE;
while(serport->serio.type && !signal_pending(current)) schedule();
current->state = TASK_RUNNING;
remove_wait_queue(&serport->wait, &wait);
serio_unregister_port(&serport->serio);
return 0;
}
/*
* serport_ldisc_ioctl() allows to set the port protocol, and device ID
*/
static int serport_ldisc_ioctl(struct tty_struct * tty, struct file * file, unsigned int cmd, unsigned long arg)
{
struct serport *serport = (struct serport*) tty->disc_data;
switch (cmd) {
case SPIOCSTYPE:
return get_user(serport->serio.type, (unsigned long *) arg);
}
return -EINVAL;
}
/*
* The line discipline structure.
*/
static struct tty_ldisc serport_ldisc = {
name: "input",
open: serport_ldisc_open,
close: serport_ldisc_close,
read: serport_ldisc_read,
ioctl: serport_ldisc_ioctl,
receive_buf: serport_ldisc_receive,
receive_room: serport_ldisc_room,
};
/*
* The functions for insering/removing us as a module.
*/
int __init serport_init(void)
{
if (tty_register_ldisc(N_MOUSE, &serport_ldisc)) {
printk(KERN_ERR "serport.c: Error registering line discipline.\n");
return -ENODEV;
}
return 0;
}
void __exit serport_exit(void)
{
tty_register_ldisc(N_MOUSE, NULL);
}
module_init(serport_init);
module_exit(serport_exit);
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