1/* 2 * Input device TTY line discipline 3 * 4 * Copyright (c) 1999-2002 Vojtech Pavlik 5 * 6 * This is a module that converts a tty line into a much simpler 7 * 'serial io port' abstraction that the input device drivers use. 8 */ 9 10/* 11 * This program is free software; you can redistribute it and/or modify it 12 * under the terms of the GNU General Public License version 2 as published by 13 * the Free Software Foundation. 14 */ 15 16#include <asm/uaccess.h> 17#include <linux/kernel.h> 18#include <linux/sched.h> 19#include <linux/slab.h> 20#include <linux/module.h> 21#include <linux/init.h> 22#include <linux/serio.h> 23#include <linux/tty.h> 24 25MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); 26MODULE_DESCRIPTION("Input device TTY line discipline"); 27MODULE_LICENSE("GPL"); 28MODULE_ALIAS_LDISC(N_MOUSE); 29 30#define SERPORT_BUSY 1 31#define SERPORT_ACTIVE 2 32#define SERPORT_DEAD 3 33 34struct serport { 35 struct tty_struct *tty; 36 wait_queue_head_t wait; 37 struct serio *serio; 38 struct serio_device_id id; 39 spinlock_t lock; 40 unsigned long flags; 41}; 42 43/* 44 * Callback functions from the serio code. 45 */ 46 47static int serport_serio_write(struct serio *serio, unsigned char data) 48{ 49 struct serport *serport = serio->port_data; 50 return -(serport->tty->ops->write(serport->tty, &data, 1) != 1); 51} 52 53static int serport_serio_open(struct serio *serio) 54{ 55 struct serport *serport = serio->port_data; 56 unsigned long flags; 57 58 spin_lock_irqsave(&serport->lock, flags); 59 set_bit(SERPORT_ACTIVE, &serport->flags); 60 spin_unlock_irqrestore(&serport->lock, flags); 61 62 return 0; 63} 64 65 66static void serport_serio_close(struct serio *serio) 67{ 68 struct serport *serport = serio->port_data; 69 unsigned long flags; 70 71 spin_lock_irqsave(&serport->lock, flags); 72 clear_bit(SERPORT_ACTIVE, &serport->flags); 73 set_bit(SERPORT_DEAD, &serport->flags); 74 spin_unlock_irqrestore(&serport->lock, flags); 75 76 wake_up_interruptible(&serport->wait); 77} 78 79/* 80 * serport_ldisc_open() is the routine that is called upon setting our line 81 * discipline on a tty. It prepares the serio struct. 82 */ 83 84static int serport_ldisc_open(struct tty_struct *tty) 85{ 86 struct serport *serport; 87 88 if (!capable(CAP_SYS_ADMIN)) 89 return -EPERM; 90 91 serport = kzalloc(sizeof(struct serport), GFP_KERNEL); 92 if (!serport) 93 return -ENOMEM; 94 95 serport->tty = tty; 96 spin_lock_init(&serport->lock); 97 init_waitqueue_head(&serport->wait); 98 99 tty->disc_data = serport; 100 tty->receive_room = 256; 101 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 102 103 return 0; 104} 105 106/* 107 * serport_ldisc_close() is the opposite of serport_ldisc_open() 108 */ 109 110static void serport_ldisc_close(struct tty_struct *tty) 111{ 112 struct serport *serport = (struct serport *) tty->disc_data; 113 114 kfree(serport); 115} 116 117/* 118 * serport_ldisc_receive() is called by the low level tty driver when characters 119 * are ready for us. We forward the characters, one by one to the 'interrupt' 120 * routine. 121 */ 122 123static void serport_ldisc_receive(struct tty_struct *tty, const unsigned char *cp, char *fp, int count) 124{ 125 struct serport *serport = (struct serport*) tty->disc_data; 126 unsigned long flags; 127 int i; 128 129 spin_lock_irqsave(&serport->lock, flags); 130 131 if (!test_bit(SERPORT_ACTIVE, &serport->flags)) 132 goto out; 133 134 for (i = 0; i < count; i++) 135 serio_interrupt(serport->serio, cp[i], 0); 136 137out: 138 spin_unlock_irqrestore(&serport->lock, flags); 139} 140 141/* 142 * serport_ldisc_read() just waits indefinitely if everything goes well. 143 * However, when the serio driver closes the serio port, it finishes, 144 * returning 0 characters. 145 */ 146 147static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file, unsigned char __user * buf, size_t nr) 148{ 149 struct serport *serport = (struct serport*) tty->disc_data; 150 struct serio *serio; 151 char name[64]; 152 153 if (test_and_set_bit(SERPORT_BUSY, &serport->flags)) 154 return -EBUSY; 155 156 serport->serio = serio = kzalloc(sizeof(struct serio), GFP_KERNEL); 157 if (!serio) 158 return -ENOMEM; 159 160 strlcpy(serio->name, "Serial port", sizeof(serio->name)); 161 snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty, name)); 162 serio->id = serport->id; 163 serio->id.type = SERIO_RS232; 164 serio->write = serport_serio_write; 165 serio->open = serport_serio_open; 166 serio->close = serport_serio_close; 167 serio->port_data = serport; 168 169 serio_register_port(serport->serio); 170 printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty, name)); 171 172 wait_event_interruptible(serport->wait, test_bit(SERPORT_DEAD, &serport->flags)); 173 serio_unregister_port(serport->serio); 174 serport->serio = NULL; 175 176 clear_bit(SERPORT_DEAD, &serport->flags); 177 clear_bit(SERPORT_BUSY, &serport->flags); 178 179 return 0; 180} 181 182/* 183 * serport_ldisc_ioctl() allows to set the port protocol, and device ID 184 */ 185 186static int serport_ldisc_ioctl(struct tty_struct * tty, struct file * file, unsigned int cmd, unsigned long arg) 187{ 188 struct serport *serport = (struct serport*) tty->disc_data; 189 unsigned long type; 190 191 if (cmd == SPIOCSTYPE) { 192 if (get_user(type, (unsigned long __user *) arg)) 193 return -EFAULT; 194 195 serport->id.proto = type & 0x000000ff; 196 serport->id.id = (type & 0x0000ff00) >> 8; 197 serport->id.extra = (type & 0x00ff0000) >> 16; 198 199 return 0; 200 } 201 202 return -EINVAL; 203} 204 205static void serport_ldisc_write_wakeup(struct tty_struct * tty) 206{ 207 struct serport *serport = (struct serport *) tty->disc_data; 208 unsigned long flags; 209 210 spin_lock_irqsave(&serport->lock, flags); 211 if (test_bit(SERPORT_ACTIVE, &serport->flags)) 212 serio_drv_write_wakeup(serport->serio); 213 spin_unlock_irqrestore(&serport->lock, flags); 214} 215 216/* 217 * The line discipline structure. 218 */ 219 220static struct tty_ldisc_ops serport_ldisc = { 221 .owner = THIS_MODULE, 222 .name = "input", 223 .open = serport_ldisc_open, 224 .close = serport_ldisc_close, 225 .read = serport_ldisc_read, 226 .ioctl = serport_ldisc_ioctl, 227 .receive_buf = serport_ldisc_receive, 228 .write_wakeup = serport_ldisc_write_wakeup 229}; 230 231/* 232 * The functions for insering/removing us as a module. 233 */ 234 235static int __init serport_init(void) 236{ 237 int retval; 238 retval = tty_register_ldisc(N_MOUSE, &serport_ldisc); 239 if (retval) 240 printk(KERN_ERR "serport.c: Error registering line discipline.\n"); 241 242 return retval; 243} 244 245static void __exit serport_exit(void) 246{ 247 tty_unregister_ldisc(N_MOUSE); 248} 249 250module_init(serport_init); 251module_exit(serport_exit); 252