drivers/input/serio/serport.c

   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 and flags, one by one to the
 120  * 'interrupt' 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         unsigned int ch_flags;
 128         int i;
 129
 130         spin_lock_irqsave(&serport->lock, flags);
 131
 132         if (!test_bit(SERPORT_ACTIVE, &serport->flags))
 133                 goto out;
 134
 135         for (i = 0; i < count; i++) {
 136                 switch (fp[i]) {
 137                 case TTY_FRAME:
 138                         ch_flags = SERIO_FRAME;
 139                         break;
 140
 141                 case TTY_PARITY:
 142                         ch_flags = SERIO_PARITY;
 143                         break;
 144
 145                 default:
 146                         ch_flags = 0;
 147                         break;
 148                 }
 149
 150                 serio_interrupt(serport->serio, cp[i], ch_flags);
 151         }
 152
 153 out:
 154         spin_unlock_irqrestore(&serport->lock, flags);
 155 }
 156
 157 /*
 158  * serport_ldisc_read() just waits indefinitely if everything goes well.
 159  * However, when the serio driver closes the serio port, it finishes,
 160  * returning 0 characters.
 161  */
 162
 163 static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file, unsigned char __user * buf, size_t nr)
 164 {
 165         struct serport *serport = (struct serport*) tty->disc_data;
 166         struct serio *serio;
 167         char name[64];
 168
 169         if (test_and_set_bit(SERPORT_BUSY, &serport->flags))
 170                 return -EBUSY;
 171
 172         serport->serio = serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
 173         if (!serio)
 174                 return -ENOMEM;
 175
 176         strlcpy(serio->name, "Serial port", sizeof(serio->name));
 177         snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty, name));
 178         serio->id = serport->id;
 179         serio->id.type = SERIO_RS232;
 180         serio->write = serport_serio_write;
 181         serio->open = serport_serio_open;
 182         serio->close = serport_serio_close;
 183         serio->port_data = serport;
 184         serio->dev.parent = tty->dev;
 185
 186         serio_register_port(serport->serio);
 187         printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty, name));
 188
 189         wait_event_interruptible(serport->wait, test_bit(SERPORT_DEAD, &serport->flags));
 190         serio_unregister_port(serport->serio);
 191         serport->serio = NULL;
 192
 193         clear_bit(SERPORT_DEAD, &serport->flags);
 194         clear_bit(SERPORT_BUSY, &serport->flags);
 195
 196         return 0;
 197 }
 198
 199 /*
 200  * serport_ldisc_ioctl() allows to set the port protocol, and device ID
 201  */
 202
 203 static int serport_ldisc_ioctl(struct tty_struct * tty, struct file * file, unsigned int cmd, unsigned long arg)
 204 {
 205         struct serport *serport = (struct serport*) tty->disc_data;
 206         unsigned long type;
 207
 208         if (cmd == SPIOCSTYPE) {
 209                 if (get_user(type, (unsigned long __user *) arg))
 210                         return -EFAULT;
 211
 212                 serport->id.proto = type & 0x000000ff;
 213                 serport->id.id    = (type & 0x0000ff00) >> 8;
 214                 serport->id.extra = (type & 0x00ff0000) >> 16;
 215
 216                 return 0;
 217         }
 218
 219         return -EINVAL;
 220 }
 221
 222 static void serport_ldisc_write_wakeup(struct tty_struct * tty)
 223 {
 224         struct serport *serport = (struct serport *) tty->disc_data;
 225         unsigned long flags;
 226
 227         spin_lock_irqsave(&serport->lock, flags);
 228         if (test_bit(SERPORT_ACTIVE, &serport->flags))
 229                 serio_drv_write_wakeup(serport->serio);
 230         spin_unlock_irqrestore(&serport->lock, flags);
 231 }
 232
 233 /*
 234  * The line discipline structure.
 235  */
 236
 237 static struct tty_ldisc_ops serport_ldisc = {
 238         .owner =        THIS_MODULE,
 239         .name =         "input",
 240         .open =         serport_ldisc_open,
 241         .close =        serport_ldisc_close,
 242         .read =         serport_ldisc_read,
 243         .ioctl =        serport_ldisc_ioctl,
 244         .receive_buf =  serport_ldisc_receive,
 245         .write_wakeup = serport_ldisc_write_wakeup
 246 };
 247
 248 /*
 249  * The functions for insering/removing us as a module.
 250  */
 251
 252 static int __init serport_init(void)
 253 {
 254         int retval;
 255         retval = tty_register_ldisc(N_MOUSE, &serport_ldisc);
 256         if (retval)
 257                 printk(KERN_ERR "serport.c: Error registering line discipline.\n");
 258
 259         return  retval;
 260 }
 261
 262 static void __exit serport_exit(void)
 263 {
 264         tty_unregister_ldisc(N_MOUSE);
 265 }
 266
 267 module_init(serport_init);
 268 module_exit(serport_exit);