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 char name[64]; 171 172 if (test_and_set_bit(SERPORT_BUSY, &serport->flags)) 173 return -EBUSY; 174 175 serport->serio = serio = kzalloc(sizeof(struct serio), GFP_KERNEL); 176 if (!serio) 177 return -ENOMEM; 178 179 strlcpy(serio->name, "Serial port", sizeof(serio->name)); 180 snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty, name)); 181 serio->id = serport->id; 182 serio->id.type = SERIO_RS232; 183 serio->write = serport_serio_write; 184 serio->open = serport_serio_open; 185 serio->close = serport_serio_close; 186 serio->port_data = serport; 187 serio->dev.parent = tty->dev; 188 189 serio_register_port(serport->serio); 190 printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty, name)); 191 192 wait_event_interruptible(serport->wait, test_bit(SERPORT_DEAD, &serport->flags)); 193 serio_unregister_port(serport->serio); 194 serport->serio = NULL; 195 196 clear_bit(SERPORT_DEAD, &serport->flags); 197 clear_bit(SERPORT_BUSY, &serport->flags); 198 199 return 0; 200 } 201 202 static void serport_set_type(struct tty_struct *tty, unsigned long type) 203 { 204 struct serport *serport = tty->disc_data; 205 206 serport->id.proto = type & 0x000000ff; 207 serport->id.id = (type & 0x0000ff00) >> 8; 208 serport->id.extra = (type & 0x00ff0000) >> 16; 209 } 210 211 /* 212 * serport_ldisc_ioctl() allows to set the port protocol, and device ID 213 */ 214 215 static int serport_ldisc_ioctl(struct tty_struct *tty, struct file *file, 216 unsigned int cmd, unsigned long arg) 217 { 218 if (cmd == SPIOCSTYPE) { 219 unsigned long type; 220 221 if (get_user(type, (unsigned long __user *) arg)) 222 return -EFAULT; 223 224 serport_set_type(tty, type); 225 return 0; 226 } 227 228 return -EINVAL; 229 } 230 231 #ifdef CONFIG_COMPAT 232 #define COMPAT_SPIOCSTYPE _IOW('q', 0x01, compat_ulong_t) 233 static long serport_ldisc_compat_ioctl(struct tty_struct *tty, 234 struct file *file, 235 unsigned int cmd, unsigned long arg) 236 { 237 if (cmd == COMPAT_SPIOCSTYPE) { 238 void __user *uarg = compat_ptr(arg); 239 compat_ulong_t compat_type; 240 241 if (get_user(compat_type, (compat_ulong_t __user *)uarg)) 242 return -EFAULT; 243 244 serport_set_type(tty, compat_type); 245 return 0; 246 } 247 248 return -EINVAL; 249 } 250 #endif 251 252 static void serport_ldisc_write_wakeup(struct tty_struct * tty) 253 { 254 struct serport *serport = (struct serport *) tty->disc_data; 255 unsigned long flags; 256 257 spin_lock_irqsave(&serport->lock, flags); 258 if (test_bit(SERPORT_ACTIVE, &serport->flags)) 259 serio_drv_write_wakeup(serport->serio); 260 spin_unlock_irqrestore(&serport->lock, flags); 261 } 262 263 /* 264 * The line discipline structure. 265 */ 266 267 static struct tty_ldisc_ops serport_ldisc = { 268 .owner = THIS_MODULE, 269 .name = "input", 270 .open = serport_ldisc_open, 271 .close = serport_ldisc_close, 272 .read = serport_ldisc_read, 273 .ioctl = serport_ldisc_ioctl, 274 #ifdef CONFIG_COMPAT 275 .compat_ioctl = serport_ldisc_compat_ioctl, 276 #endif 277 .receive_buf = serport_ldisc_receive, 278 .write_wakeup = serport_ldisc_write_wakeup 279 }; 280 281 /* 282 * The functions for insering/removing us as a module. 283 */ 284 285 static int __init serport_init(void) 286 { 287 int retval; 288 retval = tty_register_ldisc(N_MOUSE, &serport_ldisc); 289 if (retval) 290 printk(KERN_ERR "serport.c: Error registering line discipline.\n"); 291 292 return retval; 293 } 294 295 static void __exit serport_exit(void) 296 { 297 tty_unregister_ldisc(N_MOUSE); 298 } 299 300 module_init(serport_init); 301 module_exit(serport_exit); 302