/*
* Input device TTY line discipline
*
* Copyright (c) 1999-2002 Vojtech Pavlik
*
* 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 version 2 as published by
* the Free Software Foundation.
*/
#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>
MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION("Input device TTY line discipline");
MODULE_LICENSE("GPL");
MODULE_ALIAS_LDISC(N_MOUSE);
#define SERPORT_BUSY 1
struct serport {
struct tty_struct *tty;
wait_queue_head_t wait;
struct serio *serio;
unsigned long flags;
};
/*
* Callback functions from the serio code.
*/
static int serport_serio_write(struct serio *serio, unsigned char data)
{
struct serport *serport = serio->port_data;
return -(serport->tty->driver->write(serport->tty, &data, 1) != 1);
}
static void serport_serio_close(struct serio *serio)
{
struct serport *serport = serio->port_data;
serport->serio->id.type = 0;
wake_up_interruptible(&serport->wait);
}
/*
* serport_ldisc_open() is the routine that is called upon setting our line
* discipline on a tty. It prepares the serio struct.
*/
static int serport_ldisc_open(struct tty_struct *tty)
{
struct serport *serport;
struct serio *serio;
char name[64];
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
serport = kmalloc(sizeof(struct serport), GFP_KERNEL);
serio = kmalloc(sizeof(struct serio), GFP_KERNEL);
if (unlikely(!serport || !serio)) {
kfree(serport);
kfree(serio);
return -ENOMEM;
}
memset(serport, 0, sizeof(struct serport));
serport->serio = serio;
set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
serport->tty = tty;
tty->disc_data = serport;
memset(serio, 0, sizeof(struct serio));
strlcpy(serio->name, "Serial port", sizeof(serio->name));
snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty, name));
serio->id.type = SERIO_RS232;
serio->write = serport_serio_write;
serio->close = serport_serio_close;
serio->port_data = 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);
}
/*
* 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.
*
* FIXME: We should get pt_regs from the tty layer and forward them to
* serio_interrupt here.
*/
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++)
serio_interrupt(serport->serio, cp[i], 0, NULL);
}
/*
* 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 __user * buf, size_t nr)
{
struct serport *serport = (struct serport*) tty->disc_data;
char name[64];
if (test_and_set_bit(SERPORT_BUSY, &serport->flags))
return -EBUSY;
serio_register_port(serport->serio);
printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty, name));
wait_event_interruptible(serport->wait, !serport->serio->id.type);
serio_unregister_port(serport->serio);
clear_bit(SERPORT_BUSY, &serport->flags);
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;
struct serio *serio = serport->serio;
unsigned long type;
if (cmd == SPIOCSTYPE) {
if (get_user(type, (unsigned long __user *) arg))
return -EFAULT;
serio->id.proto = type & 0x000000ff;
serio->id.id = (type & 0x0000ff00) >> 8;
serio->id.extra = (type & 0x00ff0000) >> 16;
return 0;
}
return -EINVAL;
}
static void serport_ldisc_write_wakeup(struct tty_struct * tty)
{
struct serport *sp = (struct serport *) tty->disc_data;
serio_drv_write_wakeup(sp->serio);
}
/*
* The line discipline structure.
*/
static struct tty_ldisc serport_ldisc = {
.owner = THIS_MODULE,
.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,
.write_wakeup = serport_ldisc_write_wakeup
};
/*
* The functions for insering/removing us as a module.
*/
static int __init serport_init(void)
{
int retval;
retval = tty_register_ldisc(N_MOUSE, &serport_ldisc);
if (retval)
printk(KERN_ERR "serport.c: Error registering line discipline.\n");
return retval;
}
static void __exit serport_exit(void)
{
tty_register_ldisc(N_MOUSE, NULL);
}
module_init(serport_init);
module_exit(serport_exit);
