310 lines
7.0 KiB
C
310 lines
7.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Input device TTY line discipline
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*
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* Copyright (c) 1999-2002 Vojtech Pavlik
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*
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* This is a module that converts a tty line into a much simpler
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* 'serial io port' abstraction that the input device drivers use.
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*/
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#include <linux/uaccess.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/serio.h>
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#include <linux/tty.h>
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#include <linux/compat.h>
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MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
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MODULE_DESCRIPTION("Input device TTY line discipline");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_LDISC(N_MOUSE);
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#define SERPORT_BUSY 1
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#define SERPORT_ACTIVE 2
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#define SERPORT_DEAD 3
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struct serport {
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struct tty_struct *tty;
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wait_queue_head_t wait;
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struct serio *serio;
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struct serio_device_id id;
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spinlock_t lock;
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unsigned long flags;
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};
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/*
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* Callback functions from the serio code.
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*/
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static int serport_serio_write(struct serio *serio, unsigned char data)
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{
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struct serport *serport = serio->port_data;
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return -(serport->tty->ops->write(serport->tty, &data, 1) != 1);
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}
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static int serport_serio_open(struct serio *serio)
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{
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struct serport *serport = serio->port_data;
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unsigned long flags;
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spin_lock_irqsave(&serport->lock, flags);
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set_bit(SERPORT_ACTIVE, &serport->flags);
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spin_unlock_irqrestore(&serport->lock, flags);
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return 0;
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}
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static void serport_serio_close(struct serio *serio)
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{
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struct serport *serport = serio->port_data;
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unsigned long flags;
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spin_lock_irqsave(&serport->lock, flags);
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clear_bit(SERPORT_ACTIVE, &serport->flags);
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spin_unlock_irqrestore(&serport->lock, flags);
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}
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/*
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* serport_ldisc_open() is the routine that is called upon setting our line
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* discipline on a tty. It prepares the serio struct.
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*/
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static int serport_ldisc_open(struct tty_struct *tty)
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{
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struct serport *serport;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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serport = kzalloc(sizeof(struct serport), GFP_KERNEL);
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if (!serport)
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return -ENOMEM;
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serport->tty = tty;
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spin_lock_init(&serport->lock);
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init_waitqueue_head(&serport->wait);
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tty->disc_data = serport;
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tty->receive_room = 256;
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set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
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return 0;
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}
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/*
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* serport_ldisc_close() is the opposite of serport_ldisc_open()
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*/
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static void serport_ldisc_close(struct tty_struct *tty)
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{
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struct serport *serport = (struct serport *) tty->disc_data;
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kfree(serport);
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}
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/*
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* serport_ldisc_receive() is called by the low level tty driver when characters
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* are ready for us. We forward the characters and flags, one by one to the
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* 'interrupt' routine.
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*/
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static void serport_ldisc_receive(struct tty_struct *tty,
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const unsigned char *cp, const char *fp, int count)
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{
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struct serport *serport = (struct serport*) tty->disc_data;
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unsigned long flags;
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unsigned int ch_flags = 0;
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int i;
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spin_lock_irqsave(&serport->lock, flags);
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if (!test_bit(SERPORT_ACTIVE, &serport->flags))
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goto out;
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for (i = 0; i < count; i++) {
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if (fp) {
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switch (fp[i]) {
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case TTY_FRAME:
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ch_flags = SERIO_FRAME;
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break;
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case TTY_PARITY:
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ch_flags = SERIO_PARITY;
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break;
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default:
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ch_flags = 0;
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break;
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}
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}
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serio_interrupt(serport->serio, cp[i], ch_flags);
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}
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out:
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spin_unlock_irqrestore(&serport->lock, flags);
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}
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/*
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* serport_ldisc_read() just waits indefinitely if everything goes well.
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* However, when the serio driver closes the serio port, it finishes,
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* returning 0 characters.
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*/
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static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file,
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unsigned char *kbuf, size_t nr,
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void **cookie, unsigned long offset)
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{
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struct serport *serport = (struct serport*) tty->disc_data;
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struct serio *serio;
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if (test_and_set_bit(SERPORT_BUSY, &serport->flags))
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return -EBUSY;
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serport->serio = serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
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if (!serio)
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return -ENOMEM;
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strscpy(serio->name, "Serial port", sizeof(serio->name));
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snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty));
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serio->id = serport->id;
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serio->id.type = SERIO_RS232;
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serio->write = serport_serio_write;
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serio->open = serport_serio_open;
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serio->close = serport_serio_close;
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serio->port_data = serport;
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serio->dev.parent = tty->dev;
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serio_register_port(serport->serio);
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printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty));
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wait_event_interruptible(serport->wait, test_bit(SERPORT_DEAD, &serport->flags));
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serio_unregister_port(serport->serio);
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serport->serio = NULL;
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clear_bit(SERPORT_DEAD, &serport->flags);
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clear_bit(SERPORT_BUSY, &serport->flags);
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return 0;
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}
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static void serport_set_type(struct tty_struct *tty, unsigned long type)
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{
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struct serport *serport = tty->disc_data;
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serport->id.proto = type & 0x000000ff;
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serport->id.id = (type & 0x0000ff00) >> 8;
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serport->id.extra = (type & 0x00ff0000) >> 16;
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}
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/*
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* serport_ldisc_ioctl() allows to set the port protocol, and device ID
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*/
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static int serport_ldisc_ioctl(struct tty_struct *tty, unsigned int cmd,
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unsigned long arg)
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{
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if (cmd == SPIOCSTYPE) {
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unsigned long type;
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if (get_user(type, (unsigned long __user *) arg))
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return -EFAULT;
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serport_set_type(tty, type);
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return 0;
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}
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return -EINVAL;
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}
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#ifdef CONFIG_COMPAT
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#define COMPAT_SPIOCSTYPE _IOW('q', 0x01, compat_ulong_t)
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static int serport_ldisc_compat_ioctl(struct tty_struct *tty,
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unsigned int cmd, unsigned long arg)
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{
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if (cmd == COMPAT_SPIOCSTYPE) {
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void __user *uarg = compat_ptr(arg);
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compat_ulong_t compat_type;
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if (get_user(compat_type, (compat_ulong_t __user *)uarg))
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return -EFAULT;
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serport_set_type(tty, compat_type);
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return 0;
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}
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return -EINVAL;
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}
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#endif
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static void serport_ldisc_hangup(struct tty_struct *tty)
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{
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struct serport *serport = (struct serport *) tty->disc_data;
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unsigned long flags;
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spin_lock_irqsave(&serport->lock, flags);
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set_bit(SERPORT_DEAD, &serport->flags);
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spin_unlock_irqrestore(&serport->lock, flags);
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wake_up_interruptible(&serport->wait);
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}
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static void serport_ldisc_write_wakeup(struct tty_struct * tty)
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{
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struct serport *serport = (struct serport *) tty->disc_data;
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unsigned long flags;
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spin_lock_irqsave(&serport->lock, flags);
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if (test_bit(SERPORT_ACTIVE, &serport->flags))
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serio_drv_write_wakeup(serport->serio);
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spin_unlock_irqrestore(&serport->lock, flags);
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}
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/*
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* The line discipline structure.
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*/
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static struct tty_ldisc_ops serport_ldisc = {
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.owner = THIS_MODULE,
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.num = N_MOUSE,
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.name = "input",
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.open = serport_ldisc_open,
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.close = serport_ldisc_close,
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.read = serport_ldisc_read,
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.ioctl = serport_ldisc_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = serport_ldisc_compat_ioctl,
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#endif
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.receive_buf = serport_ldisc_receive,
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.hangup = serport_ldisc_hangup,
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.write_wakeup = serport_ldisc_write_wakeup
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};
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/*
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* The functions for insering/removing us as a module.
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*/
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static int __init serport_init(void)
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{
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int retval;
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retval = tty_register_ldisc(&serport_ldisc);
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if (retval)
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printk(KERN_ERR "serport.c: Error registering line discipline.\n");
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return retval;
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}
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static void __exit serport_exit(void)
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{
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tty_unregister_ldisc(&serport_ldisc);
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}
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module_init(serport_init);
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module_exit(serport_exit);
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