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 25 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); 26 MODULE_DESCRIPTION("Input device TTY line discipline"); 27 MODULE_LICENSE("GPL"); 28 MODULE_ALIAS_LDISC(N_MOUSE); 29 30 #define SERPORT_BUSY 1 31 #define SERPORT_ACTIVE 2 32 #define SERPORT_DEAD 3 33 34 struct 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 47 static 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 53 static 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 66 static 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 84 static 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 */ 109 110 static 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 */ 122 123 static 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); 136 137 out: 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 */ 146 147 static 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 serio->dev.parent = tty->dev; 169 170 serio_register_port(serport->serio); 171 printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty, name)); 172 173 wait_event_interruptible(serport->wait, test_bit(SERPORT_DEAD, &serport->flags)); 174 serio_unregister_port(serport->serio); 175 serport->serio = NULL; 176 177 clear_bit(SERPORT_DEAD, &serport->flags); 178 clear_bit(SERPORT_BUSY, &serport->flags); 179 180 return 0; 181 } 182 183 /* 184 * serport_ldisc_ioctl() allows to set the port protocol, and device ID 185 */ 186 187 static int serport_ldisc_ioctl(struct tty_struct * tty, struct file * file, unsigned int cmd, unsigned long arg) 188 { 189 struct serport *serport = (struct serport*) tty->disc_data; 190 unsigned long type; 191 192 if (cmd == SPIOCSTYPE) { 193 if (get_user(type, (unsigned long __user *) arg)) 194 return -EFAULT; 195 196 serport->id.proto = type & 0x000000ff; 197 serport->id.id = (type & 0x0000ff00) >> 8; 198 serport->id.extra = (type & 0x00ff0000) >> 16; 199 200 return 0; 201 } 202 203 return -EINVAL; 204 } 205 206 static void serport_ldisc_write_wakeup(struct tty_struct * tty) 207 { 208 struct serport *serport = (struct serport *) tty->disc_data; 209 unsigned long flags; 210 211 spin_lock_irqsave(&serport->lock, flags); 212 if (test_bit(SERPORT_ACTIVE, &serport->flags)) 213 serio_drv_write_wakeup(serport->serio); 214 spin_unlock_irqrestore(&serport->lock, flags); 215 } 216 217 /* 218 * The line discipline structure. 219 */ 220 221 static struct tty_ldisc_ops serport_ldisc = { 222 .owner = THIS_MODULE, 223 .name = "input", 224 .open = serport_ldisc_open, 225 .close = serport_ldisc_close, 226 .read = serport_ldisc_read, 227 .ioctl = serport_ldisc_ioctl, 228 .receive_buf = serport_ldisc_receive, 229 .write_wakeup = serport_ldisc_write_wakeup 230 }; 231 232 /* 233 * The functions for insering/removing us as a module. 234 */ 235 236 static int __init serport_init(void) 237 { 238 int retval; 239 retval = tty_register_ldisc(N_MOUSE, &serport_ldisc); 240 if (retval) 241 printk(KERN_ERR "serport.c: Error registering line discipline.\n"); 242 243 return retval; 244 } 245 246 static void __exit serport_exit(void) 247 { 248 tty_unregister_ldisc(N_MOUSE); 249 } 250 251 module_init(serport_init); 252 module_exit(serport_exit); 253