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311 lines
7.1 KiB
311 lines
7.1 KiB
// 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 <[email protected]>"); |
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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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strlcpy(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, struct file *file, |
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unsigned int cmd, 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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struct file *file, |
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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 int 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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return 0; |
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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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