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 <linux/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 spin_unlock_irqrestore(&serport->lock, flags); 75 } 76 77 /* 78 * serport_ldisc_open() is the routine that is called upon setting our line 79 * discipline on a tty. It prepares the serio struct. 80 */ 81 82 static int serport_ldisc_open(struct tty_struct *tty) 83 { 84 struct serport *serport; 85 86 if (!capable(CAP_SYS_ADMIN)) 87 return -EPERM; 88 89 serport = kzalloc(sizeof(struct serport), GFP_KERNEL); 90 if (!serport) 91 return -ENOMEM; 92 93 serport->tty = tty; 94 spin_lock_init(&serport->lock); 95 init_waitqueue_head(&serport->wait); 96 97 tty->disc_data = serport; 98 tty->receive_room = 256; 99 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 100 101 return 0; 102 } 103 104 /* 105 * serport_ldisc_close() is the opposite of serport_ldisc_open() 106 */ 107 108 static void serport_ldisc_close(struct tty_struct *tty) 109 { 110 struct serport *serport = (struct serport *) tty->disc_data; 111 112 kfree(serport); 113 } 114 115 /* 116 * serport_ldisc_receive() is called by the low level tty driver when characters 117 * are ready for us. We forward the characters and flags, one by one to the 118 * 'interrupt' routine. 119 */ 120 121 static void serport_ldisc_receive(struct tty_struct *tty, const unsigned char *cp, char *fp, int count) 122 { 123 struct serport *serport = (struct serport*) tty->disc_data; 124 unsigned long flags; 125 unsigned int ch_flags = 0; 126 int i; 127 128 spin_lock_irqsave(&serport->lock, flags); 129 130 if (!test_bit(SERPORT_ACTIVE, &serport->flags)) 131 goto out; 132 133 for (i = 0; i < count; i++) { 134 if (fp) { 135 switch (fp[i]) { 136 case TTY_FRAME: 137 ch_flags = SERIO_FRAME; 138 break; 139 140 case TTY_PARITY: 141 ch_flags = SERIO_PARITY; 142 break; 143 144 default: 145 ch_flags = 0; 146 break; 147 } 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; 167 168 if (test_and_set_bit(SERPORT_BUSY, &serport->flags)) 169 return -EBUSY; 170 171 serport->serio = serio = kzalloc(sizeof(struct serio), GFP_KERNEL); 172 if (!serio) 173 return -ENOMEM; 174 175 strlcpy(serio->name, "Serial port", sizeof(serio->name)); 176 snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty)); 177 serio->id = serport->id; 178 serio->id.type = SERIO_RS232; 179 serio->write = serport_serio_write; 180 serio->open = serport_serio_open; 181 serio->close = serport_serio_close; 182 serio->port_data = serport; 183 serio->dev.parent = tty->dev; 184 185 serio_register_port(serport->serio); 186 printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty)); 187 188 wait_event_interruptible(serport->wait, test_bit(SERPORT_DEAD, &serport->flags)); 189 serio_unregister_port(serport->serio); 190 serport->serio = NULL; 191 192 clear_bit(SERPORT_DEAD, &serport->flags); 193 clear_bit(SERPORT_BUSY, &serport->flags); 194 195 return 0; 196 } 197 198 static void serport_set_type(struct tty_struct *tty, unsigned long type) 199 { 200 struct serport *serport = tty->disc_data; 201 202 serport->id.proto = type & 0x000000ff; 203 serport->id.id = (type & 0x0000ff00) >> 8; 204 serport->id.extra = (type & 0x00ff0000) >> 16; 205 } 206 207 /* 208 * serport_ldisc_ioctl() allows to set the port protocol, and device ID 209 */ 210 211 static int serport_ldisc_ioctl(struct tty_struct *tty, struct file *file, 212 unsigned int cmd, unsigned long arg) 213 { 214 if (cmd == SPIOCSTYPE) { 215 unsigned long type; 216 217 if (get_user(type, (unsigned long __user *) arg)) 218 return -EFAULT; 219 220 serport_set_type(tty, type); 221 return 0; 222 } 223 224 return -EINVAL; 225 } 226 227 #ifdef CONFIG_COMPAT 228 #define COMPAT_SPIOCSTYPE _IOW('q', 0x01, compat_ulong_t) 229 static long serport_ldisc_compat_ioctl(struct tty_struct *tty, 230 struct file *file, 231 unsigned int cmd, unsigned long arg) 232 { 233 if (cmd == COMPAT_SPIOCSTYPE) { 234 void __user *uarg = compat_ptr(arg); 235 compat_ulong_t compat_type; 236 237 if (get_user(compat_type, (compat_ulong_t __user *)uarg)) 238 return -EFAULT; 239 240 serport_set_type(tty, compat_type); 241 return 0; 242 } 243 244 return -EINVAL; 245 } 246 #endif 247 248 static int serport_ldisc_hangup(struct tty_struct *tty) 249 { 250 struct serport *serport = (struct serport *) tty->disc_data; 251 unsigned long flags; 252 253 spin_lock_irqsave(&serport->lock, flags); 254 set_bit(SERPORT_DEAD, &serport->flags); 255 spin_unlock_irqrestore(&serport->lock, flags); 256 257 wake_up_interruptible(&serport->wait); 258 return 0; 259 } 260 261 static void serport_ldisc_write_wakeup(struct tty_struct * tty) 262 { 263 struct serport *serport = (struct serport *) tty->disc_data; 264 unsigned long flags; 265 266 spin_lock_irqsave(&serport->lock, flags); 267 if (test_bit(SERPORT_ACTIVE, &serport->flags)) 268 serio_drv_write_wakeup(serport->serio); 269 spin_unlock_irqrestore(&serport->lock, flags); 270 } 271 272 /* 273 * The line discipline structure. 274 */ 275 276 static struct tty_ldisc_ops serport_ldisc = { 277 .owner = THIS_MODULE, 278 .name = "input", 279 .open = serport_ldisc_open, 280 .close = serport_ldisc_close, 281 .read = serport_ldisc_read, 282 .ioctl = serport_ldisc_ioctl, 283 #ifdef CONFIG_COMPAT 284 .compat_ioctl = serport_ldisc_compat_ioctl, 285 #endif 286 .receive_buf = serport_ldisc_receive, 287 .hangup = serport_ldisc_hangup, 288 .write_wakeup = serport_ldisc_write_wakeup 289 }; 290 291 /* 292 * The functions for insering/removing us as a module. 293 */ 294 295 static int __init serport_init(void) 296 { 297 int retval; 298 retval = tty_register_ldisc(N_MOUSE, &serport_ldisc); 299 if (retval) 300 printk(KERN_ERR "serport.c: Error registering line discipline.\n"); 301 302 return retval; 303 } 304 305 static void __exit serport_exit(void) 306 { 307 tty_unregister_ldisc(N_MOUSE); 308 } 309 310 module_init(serport_init); 311 module_exit(serport_exit); 312