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/slab.h> 19 #include <linux/module.h> 20 #include <linux/init.h> 21 #include <linux/serio.h> 22 #include <linux/tty.h> 23 24 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>"); 25 MODULE_DESCRIPTION("Input device TTY line discipline"); 26 MODULE_LICENSE("GPL"); 27 MODULE_ALIAS_LDISC(N_MOUSE); 28 29 #define SERPORT_BUSY 1 30 #define SERPORT_ACTIVE 2 31 #define SERPORT_DEAD 3 32 33 struct serport { 34 struct tty_struct *tty; 35 wait_queue_head_t wait; 36 struct serio *serio; 37 struct serio_device_id id; 38 spinlock_t lock; 39 unsigned long flags; 40 }; 41 42 /* 43 * Callback functions from the serio code. 44 */ 45 46 static int serport_serio_write(struct serio *serio, unsigned char data) 47 { 48 struct serport *serport = serio->port_data; 49 return -(serport->tty->driver->write(serport->tty, &data, 1) != 1); 50 } 51 52 static int serport_serio_open(struct serio *serio) 53 { 54 struct serport *serport = serio->port_data; 55 unsigned long flags; 56 57 spin_lock_irqsave(&serport->lock, flags); 58 set_bit(SERPORT_ACTIVE, &serport->flags); 59 spin_unlock_irqrestore(&serport->lock, flags); 60 61 return 0; 62 } 63 64 65 static void serport_serio_close(struct serio *serio) 66 { 67 struct serport *serport = serio->port_data; 68 unsigned long flags; 69 70 spin_lock_irqsave(&serport->lock, flags); 71 clear_bit(SERPORT_ACTIVE, &serport->flags); 72 set_bit(SERPORT_DEAD, &serport->flags); 73 spin_unlock_irqrestore(&serport->lock, flags); 74 75 wake_up_interruptible(&serport->wait); 76 } 77 78 /* 79 * serport_ldisc_open() is the routine that is called upon setting our line 80 * discipline on a tty. It prepares the serio struct. 81 */ 82 83 static int serport_ldisc_open(struct tty_struct *tty) 84 { 85 struct serport *serport; 86 87 if (!capable(CAP_SYS_ADMIN)) 88 return -EPERM; 89 90 serport = kzalloc(sizeof(struct serport), GFP_KERNEL); 91 if (!serport) 92 return -ENOMEM; 93 94 serport->tty = tty; 95 spin_lock_init(&serport->lock); 96 init_waitqueue_head(&serport->wait); 97 98 tty->disc_data = serport; 99 tty->receive_room = 256; 100 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 101 102 return 0; 103 } 104 105 /* 106 * serport_ldisc_close() is the opposite of serport_ldisc_open() 107 */ 108 109 static void serport_ldisc_close(struct tty_struct *tty) 110 { 111 struct serport *serport = (struct serport *) tty->disc_data; 112 113 kfree(serport); 114 } 115 116 /* 117 * serport_ldisc_receive() is called by the low level tty driver when characters 118 * are ready for us. We forward the characters, one by one to the 'interrupt' 119 * routine. 120 */ 121 122 static void serport_ldisc_receive(struct tty_struct *tty, const unsigned char *cp, char *fp, int count) 123 { 124 struct serport *serport = (struct serport*) tty->disc_data; 125 unsigned long flags; 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 serio_interrupt(serport->serio, cp[i], 0); 135 136 out: 137 spin_unlock_irqrestore(&serport->lock, flags); 138 } 139 140 /* 141 * serport_ldisc_read() just waits indefinitely if everything goes well. 142 * However, when the serio driver closes the serio port, it finishes, 143 * returning 0 characters. 144 */ 145 146 static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file, unsigned char __user * buf, size_t nr) 147 { 148 struct serport *serport = (struct serport*) tty->disc_data; 149 struct serio *serio; 150 char name[64]; 151 152 if (test_and_set_bit(SERPORT_BUSY, &serport->flags)) 153 return -EBUSY; 154 155 serport->serio = serio = kzalloc(sizeof(struct serio), GFP_KERNEL); 156 if (!serio) 157 return -ENOMEM; 158 159 strlcpy(serio->name, "Serial port", sizeof(serio->name)); 160 snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty, name)); 161 serio->id = serport->id; 162 serio->id.type = SERIO_RS232; 163 serio->write = serport_serio_write; 164 serio->open = serport_serio_open; 165 serio->close = serport_serio_close; 166 serio->port_data = serport; 167 168 serio_register_port(serport->serio); 169 printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty, name)); 170 171 wait_event_interruptible(serport->wait, test_bit(SERPORT_DEAD, &serport->flags)); 172 serio_unregister_port(serport->serio); 173 serport->serio = NULL; 174 175 clear_bit(SERPORT_DEAD, &serport->flags); 176 clear_bit(SERPORT_BUSY, &serport->flags); 177 178 return 0; 179 } 180 181 /* 182 * serport_ldisc_ioctl() allows to set the port protocol, and device ID 183 */ 184 185 static int serport_ldisc_ioctl(struct tty_struct * tty, struct file * file, unsigned int cmd, unsigned long arg) 186 { 187 struct serport *serport = (struct serport*) tty->disc_data; 188 unsigned long type; 189 190 if (cmd == SPIOCSTYPE) { 191 if (get_user(type, (unsigned long __user *) arg)) 192 return -EFAULT; 193 194 serport->id.proto = type & 0x000000ff; 195 serport->id.id = (type & 0x0000ff00) >> 8; 196 serport->id.extra = (type & 0x00ff0000) >> 16; 197 198 return 0; 199 } 200 201 return -EINVAL; 202 } 203 204 static void serport_ldisc_write_wakeup(struct tty_struct * tty) 205 { 206 struct serport *serport = (struct serport *) tty->disc_data; 207 unsigned long flags; 208 209 spin_lock_irqsave(&serport->lock, flags); 210 if (test_bit(SERPORT_ACTIVE, &serport->flags)) 211 serio_drv_write_wakeup(serport->serio); 212 spin_unlock_irqrestore(&serport->lock, flags); 213 } 214 215 /* 216 * The line discipline structure. 217 */ 218 219 static struct tty_ldisc serport_ldisc = { 220 .owner = THIS_MODULE, 221 .name = "input", 222 .open = serport_ldisc_open, 223 .close = serport_ldisc_close, 224 .read = serport_ldisc_read, 225 .ioctl = serport_ldisc_ioctl, 226 .receive_buf = serport_ldisc_receive, 227 .write_wakeup = serport_ldisc_write_wakeup 228 }; 229 230 /* 231 * The functions for insering/removing us as a module. 232 */ 233 234 static int __init serport_init(void) 235 { 236 int retval; 237 retval = tty_register_ldisc(N_MOUSE, &serport_ldisc); 238 if (retval) 239 printk(KERN_ERR "serport.c: Error registering line discipline.\n"); 240 241 return retval; 242 } 243 244 static void __exit serport_exit(void) 245 { 246 tty_unregister_ldisc(N_MOUSE); 247 } 248 249 module_init(serport_init); 250 module_exit(serport_exit); 251