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 #include <linux/compat.h>
  25
  26 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
  27 MODULE_DESCRIPTION("Input device TTY line discipline");
  28 MODULE_LICENSE("GPL");
  29 MODULE_ALIAS_LDISC(N_MOUSE);
  30
  31 #define SERPORT_BUSY    1
  32 #define SERPORT_ACTIVE  2
  33 #define SERPORT_DEAD    3
  34
  35 struct serport {
  36         struct tty_struct *tty;
  37         wait_queue_head_t wait;
  38         struct serio *serio;
  39         struct serio_device_id id;
  40         spinlock_t lock;
  41         unsigned long flags;
  42 };
  43
  44 /*
  45  * Callback functions from the serio code.
  46  */
  47
  48 static int serport_serio_write(struct serio *serio, unsigned char data)
  49 {
  50         struct serport *serport = serio->port_data;
  51         return -(serport->tty->ops->write(serport->tty, &data, 1) != 1);
  52 }
  53
  54 static int serport_serio_open(struct serio *serio)
  55 {
  56         struct serport *serport = serio->port_data;
  57         unsigned long flags;
  58
  59         spin_lock_irqsave(&serport->lock, flags);
  60         set_bit(SERPORT_ACTIVE, &serport->flags);
  61         spin_unlock_irqrestore(&serport->lock, flags);
  62
  63         return 0;
  64 }
  65
  66
  67 static void serport_serio_close(struct serio *serio)
  68 {
  69         struct serport *serport = serio->port_data;
  70         unsigned long flags;
  71
  72         spin_lock_irqsave(&serport->lock, flags);
  73         clear_bit(SERPORT_ACTIVE, &serport->flags);
  74         set_bit(SERPORT_DEAD, &serport->flags);
  75         spin_unlock_irqrestore(&serport->lock, flags);
  76
  77         wake_up_interruptible(&serport->wait);
  78 }
  79
  80 /*
  81  * serport_ldisc_open() is the routine that is called upon setting our line
  82  * discipline on a tty. It prepares the serio struct.
  83  */
  84
  85 static int serport_ldisc_open(struct tty_struct *tty)
  86 {
  87         struct serport *serport;
  88
  89         if (!capable(CAP_SYS_ADMIN))
  90                 return -EPERM;
  91
  92         serport = kzalloc(sizeof(struct serport), GFP_KERNEL);
  93         if (!serport)
  94                 return -ENOMEM;
  95
  96         serport->tty = tty;
  97         spin_lock_init(&serport->lock);
  98         init_waitqueue_head(&serport->wait);
  99
 100         tty->disc_data = serport;
 101         tty->receive_room = 256;
 102         set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 103
 104         return 0;
 105 }
 106
 107 /*
 108  * serport_ldisc_close() is the opposite of serport_ldisc_open()
 109  */
 110
 111 static void serport_ldisc_close(struct tty_struct *tty)
 112 {
 113         struct serport *serport = (struct serport *) tty->disc_data;
 114
 115         kfree(serport);
 116 }
 117
 118 /*
 119  * serport_ldisc_receive() is called by the low level tty driver when characters
 120  * are ready for us. We forward the characters and flags, one by one to the
 121  * 'interrupt' routine.
 122  */
 123
 124 static void serport_ldisc_receive(struct tty_struct *tty, const unsigned char *cp, char *fp, int count)
 125 {
 126         struct serport *serport = (struct serport*) tty->disc_data;
 127         unsigned long flags;
 128         unsigned int ch_flags = 0;
 129         int i;
 130
 131         spin_lock_irqsave(&serport->lock, flags);
 132
 133         if (!test_bit(SERPORT_ACTIVE, &serport->flags))
 134                 goto out;
 135
 136         for (i = 0; i < count; i++) {
 137                 if (fp) {
 138                         switch (fp[i]) {
 139                         case TTY_FRAME:
 140                                 ch_flags = SERIO_FRAME;
 141                                 break;
 142
 143                         case TTY_PARITY:
 144                                 ch_flags = SERIO_PARITY;
 145                                 break;
 146
 147                         default:
 148                                 ch_flags = 0;
 149                                 break;
 150                         }
 151                 }
 152
 153                 serio_interrupt(serport->serio, cp[i], ch_flags);
 154         }
 155
 156 out:
 157         spin_unlock_irqrestore(&serport->lock, flags);
 158 }
 159
 160 /*
 161  * serport_ldisc_read() just waits indefinitely if everything goes well.
 162  * However, when the serio driver closes the serio port, it finishes,
 163  * returning 0 characters.
 164  */
 165
 166 static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file, unsigned char __user * buf, size_t nr)
 167 {
 168         struct serport *serport = (struct serport*) tty->disc_data;
 169         struct serio *serio;
 170
 171         if (test_and_set_bit(SERPORT_BUSY, &serport->flags))
 172                 return -EBUSY;
 173
 174         serport->serio = serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
 175         if (!serio)
 176                 return -ENOMEM;
 177
 178         strlcpy(serio->name, "Serial port", sizeof(serio->name));
 179         snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty));
 180         serio->id = serport->id;
 181         serio->id.type = SERIO_RS232;
 182         serio->write = serport_serio_write;
 183         serio->open = serport_serio_open;
 184         serio->close = serport_serio_close;
 185         serio->port_data = serport;
 186         serio->dev.parent = tty->dev;
 187
 188         serio_register_port(serport->serio);
 189         printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty));
 190
 191         wait_event_interruptible(serport->wait, test_bit(SERPORT_DEAD, &serport->flags));
 192         serio_unregister_port(serport->serio);
 193         serport->serio = NULL;
 194
 195         clear_bit(SERPORT_DEAD, &serport->flags);
 196         clear_bit(SERPORT_BUSY, &serport->flags);
 197
 198         return 0;
 199 }
 200
 201 static void serport_set_type(struct tty_struct *tty, unsigned long type)
 202 {
 203         struct serport *serport = tty->disc_data;
 204
 205         serport->id.proto = type & 0x000000ff;
 206         serport->id.id    = (type & 0x0000ff00) >> 8;
 207         serport->id.extra = (type & 0x00ff0000) >> 16;
 208 }
 209
 210 /*
 211  * serport_ldisc_ioctl() allows to set the port protocol, and device ID
 212  */
 213
 214 static int serport_ldisc_ioctl(struct tty_struct *tty, struct file *file,
 215                                unsigned int cmd, unsigned long arg)
 216 {
 217         if (cmd == SPIOCSTYPE) {
 218                 unsigned long type;
 219
 220                 if (get_user(type, (unsigned long __user *) arg))
 221                         return -EFAULT;
 222
 223                 serport_set_type(tty, type);
 224                 return 0;
 225         }
 226
 227         return -EINVAL;
 228 }
 229
 230 #ifdef CONFIG_COMPAT
 231 #define COMPAT_SPIOCSTYPE       _IOW('q', 0x01, compat_ulong_t)
 232 static long serport_ldisc_compat_ioctl(struct tty_struct *tty,
 233                                        struct file *file,
 234                                        unsigned int cmd, unsigned long arg)
 235 {
 236         if (cmd == COMPAT_SPIOCSTYPE) {
 237                 void __user *uarg = compat_ptr(arg);
 238                 compat_ulong_t compat_type;
 239
 240                 if (get_user(compat_type, (compat_ulong_t __user *)uarg))
 241                         return -EFAULT;
 242
 243                 serport_set_type(tty, compat_type);
 244                 return 0;
 245         }
 246
 247         return -EINVAL;
 248 }
 249 #endif
 250
 251 static void serport_ldisc_write_wakeup(struct tty_struct * tty)
 252 {
 253         struct serport *serport = (struct serport *) tty->disc_data;
 254         unsigned long flags;
 255
 256         spin_lock_irqsave(&serport->lock, flags);
 257         if (test_bit(SERPORT_ACTIVE, &serport->flags))
 258                 serio_drv_write_wakeup(serport->serio);
 259         spin_unlock_irqrestore(&serport->lock, flags);
 260 }
 261
 262 /*
 263  * The line discipline structure.
 264  */
 265
 266 static struct tty_ldisc_ops serport_ldisc = {
 267         .owner =        THIS_MODULE,
 268         .name =         "input",
 269         .open =         serport_ldisc_open,
 270         .close =        serport_ldisc_close,
 271         .read =         serport_ldisc_read,
 272         .ioctl =        serport_ldisc_ioctl,
 273 #ifdef CONFIG_COMPAT
 274         .compat_ioctl = serport_ldisc_compat_ioctl,
 275 #endif
 276         .receive_buf =  serport_ldisc_receive,
 277         .write_wakeup = serport_ldisc_write_wakeup
 278 };
 279
 280 /*
 281  * The functions for insering/removing us as a module.
 282  */
 283
 284 static int __init serport_init(void)
 285 {
 286         int retval;
 287         retval = tty_register_ldisc(N_MOUSE, &serport_ldisc);
 288         if (retval)
 289                 printk(KERN_ERR "serport.c: Error registering line discipline.\n");
 290
 291         return  retval;
 292 }
 293
 294 static void __exit serport_exit(void)
 295 {
 296         tty_unregister_ldisc(N_MOUSE);
 297 }
 298
 299 module_init(serport_init);
 300 module_exit(serport_exit);