/* * 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 #define SERPORT_ACTIVE 2 #define SERPORT_DEAD 3 struct serport { struct tty_struct *tty; wait_queue_head_t wait; struct serio *serio; struct serio_device_id id; spinlock_t lock; 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 int serport_serio_open(struct serio *serio) { struct serport *serport = serio->port_data; unsigned long flags; spin_lock_irqsave(&serport->lock, flags); set_bit(SERPORT_ACTIVE, &serport->flags); spin_unlock_irqrestore(&serport->lock, flags); return 0; } static void serport_serio_close(struct serio *serio) { struct serport *serport = serio->port_data; unsigned long flags; spin_lock_irqsave(&serport->lock, flags); clear_bit(SERPORT_ACTIVE, &serport->flags); set_bit(SERPORT_DEAD, &serport->flags); spin_unlock_irqrestore(&serport->lock, flags); 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; if (!capable(CAP_SYS_ADMIN)) return -EPERM; serport = kcalloc(1, sizeof(struct serport), GFP_KERNEL); if (!serport) return -ENOMEM; serport->tty = tty; spin_lock_init(&serport->lock); init_waitqueue_head(&serport->wait); tty->disc_data = serport; set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 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; unsigned long flags; int i; spin_lock_irqsave(&serport->lock, flags); if (!test_bit(SERPORT_ACTIVE, &serport->flags)) goto out; for (i = 0; i < count; i++) serio_interrupt(serport->serio, cp[i], 0, NULL); out: spin_unlock_irqrestore(&serport->lock, flags); } /* * 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; struct serio *serio; char name[64]; if (test_and_set_bit(SERPORT_BUSY, &serport->flags)) return -EBUSY; serport->serio = serio = kcalloc(1, sizeof(struct serio), GFP_KERNEL); if (!serio) return -ENOMEM; strlcpy(serio->name, "Serial port", sizeof(serio->name)); snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty, name)); serio->id = serport->id; serio->id.type = SERIO_RS232; serio->write = serport_serio_write; serio->open = serport_serio_open; serio->close = serport_serio_close; serio->port_data = serport; serio_register_port(serport->serio); printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty, name)); wait_event_interruptible(serport->wait, test_bit(SERPORT_DEAD, &serport->flags)); serio_unregister_port(serport->serio); serport->serio = NULL; clear_bit(SERPORT_DEAD, &serport->flags); 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; unsigned long type; if (cmd == SPIOCSTYPE) { if (get_user(type, (unsigned long __user *) arg)) return -EFAULT; serport->id.proto = type & 0x000000ff; serport->id.id = (type & 0x0000ff00) >> 8; serport->id.extra = (type & 0x00ff0000) >> 16; return 0; } return -EINVAL; } static void serport_ldisc_write_wakeup(struct tty_struct * tty) { struct serport *serport = (struct serport *) tty->disc_data; unsigned long flags; spin_lock_irqsave(&serport->lock, flags); if (test_bit(SERPORT_ACTIVE, &serport->flags)) serio_drv_write_wakeup(serport->serio); spin_unlock_irqrestore(&serport->lock, flags); } /* * 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_unregister_ldisc(N_MOUSE); } module_init(serport_init); module_exit(serport_exit);