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;
 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                 switch (fp[i]) {
 138                 case TTY_FRAME:
 139                         ch_flags = SERIO_FRAME;
 140                         break;
 141
 142                 case TTY_PARITY:
 143                         ch_flags = SERIO_PARITY;
 144                         break;
 145
 146                 default:
 147                         ch_flags = 0;
 148                         break;
 149                 }
 150
 151                 serio_interrupt(serport->serio, cp[i], ch_flags);
 152         }
 153
 154 out:
 155         spin_unlock_irqrestore(&serport->lock, flags);
 156 }
 157
 158 /*
 159  * serport_ldisc_read() just waits indefinitely if everything goes well.
 160  * However, when the serio driver closes the serio port, it finishes,
 161  * returning 0 characters.
 162  */
 163
 164 static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file, unsigned char __user * buf, size_t nr)
 165 {
 166         struct serport *serport = (struct serport*) tty->disc_data;
 167         struct serio *serio;
 168         char name[64];
 169
 170         if (test_and_set_bit(SERPORT_BUSY, &serport->flags))
 171                 return -EBUSY;
 172
 173         serport->serio = serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
 174         if (!serio)
 175                 return -ENOMEM;
 176
 177         strlcpy(serio->name, "Serial port", sizeof(serio->name));
 178         snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty, name));
 179         serio->id = serport->id;
 180         serio->id.type = SERIO_RS232;
 181         serio->write = serport_serio_write;
 182         serio->open = serport_serio_open;
 183         serio->close = serport_serio_close;
 184         serio->port_data = serport;
 185         serio->dev.parent = tty->dev;
 186
 187         serio_register_port(serport->serio);
 188         printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty, name));
 189
 190         wait_event_interruptible(serport->wait, test_bit(SERPORT_DEAD, &serport->flags));
 191         serio_unregister_port(serport->serio);
 192         serport->serio = NULL;
 193
 194         clear_bit(SERPORT_DEAD, &serport->flags);
 195         clear_bit(SERPORT_BUSY, &serport->flags);
 196
 197         return 0;
 198 }
 199
 200 static void serport_set_type(struct tty_struct *tty, unsigned long type)
 201 {
 202         struct serport *serport = tty->disc_data;
 203
 204         serport->id.proto = type & 0x000000ff;
 205         serport->id.id    = (type & 0x0000ff00) >> 8;
 206         serport->id.extra = (type & 0x00ff0000) >> 16;
 207 }
 208
 209 /*
 210  * serport_ldisc_ioctl() allows to set the port protocol, and device ID
 211  */
 212
 213 static int serport_ldisc_ioctl(struct tty_struct *tty, struct file *file,
 214                                unsigned int cmd, unsigned long arg)
 215 {
 216         if (cmd == SPIOCSTYPE) {
 217                 unsigned long type;
 218
 219                 if (get_user(type, (unsigned long __user *) arg))
 220                         return -EFAULT;
 221
 222                 serport_set_type(tty, type);
 223                 return 0;
 224         }
 225
 226         return -EINVAL;
 227 }
 228
 229 #ifdef CONFIG_COMPAT
 230 #define COMPAT_SPIOCSTYPE       _IOW('q', 0x01, compat_ulong_t)
 231 static long serport_ldisc_compat_ioctl(struct tty_struct *tty,
 232                                        struct file *file,
 233                                        unsigned int cmd, unsigned long arg)
 234 {
 235         if (cmd == COMPAT_SPIOCSTYPE) {
 236                 void __user *uarg = compat_ptr(arg);
 237                 compat_ulong_t compat_type;
 238
 239                 if (get_user(compat_type, (compat_ulong_t __user *)uarg))
 240                         return -EFAULT;
 241
 242                 serport_set_type(tty, compat_type);
 243                 return 0;
 244         }
 245
 246         return -EINVAL;
 247 }
 248 #endif
 249
 250 static void serport_ldisc_write_wakeup(struct tty_struct * tty)
 251 {
 252         struct serport *serport = (struct serport *) tty->disc_data;
 253         unsigned long flags;
 254
 255         spin_lock_irqsave(&serport->lock, flags);
 256         if (test_bit(SERPORT_ACTIVE, &serport->flags))
 257                 serio_drv_write_wakeup(serport->serio);
 258         spin_unlock_irqrestore(&serport->lock, flags);
 259 }
 260
 261 /*
 262  * The line discipline structure.
 263  */
 264
 265 static struct tty_ldisc_ops serport_ldisc = {
 266         .owner =        THIS_MODULE,
 267         .name =         "input",
 268         .open =         serport_ldisc_open,
 269         .close =        serport_ldisc_close,
 270         .read =         serport_ldisc_read,
 271         .ioctl =        serport_ldisc_ioctl,
 272 #ifdef CONFIG_COMPAT
 273         .compat_ioctl = serport_ldisc_compat_ioctl,
 274 #endif
 275         .receive_buf =  serport_ldisc_receive,
 276         .write_wakeup = serport_ldisc_write_wakeup
 277 };
 278
 279 /*
 280  * The functions for insering/removing us as a module.
 281  */
 282
 283 static int __init serport_init(void)
 284 {
 285         int retval;
 286         retval = tty_register_ldisc(N_MOUSE, &serport_ldisc);
 287         if (retval)
 288                 printk(KERN_ERR "serport.c: Error registering line discipline.\n");
 289
 290         return  retval;
 291 }
 292
 293 static void __exit serport_exit(void)
 294 {
 295         tty_unregister_ldisc(N_MOUSE);
 296 }
 297
 298 module_init(serport_init);
 299 module_exit(serport_exit);