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 31 struct serport { 32 struct tty_struct *tty; 33 wait_queue_head_t wait; 34 struct serio *serio; 35 unsigned long flags; 36 }; 37 38 /* 39 * Callback functions from the serio code. 40 */ 41 42 static int serport_serio_write(struct serio *serio, unsigned char data) 43 { 44 struct serport *serport = serio->port_data; 45 return -(serport->tty->driver->write(serport->tty, &data, 1) != 1); 46 } 47 48 static void serport_serio_close(struct serio *serio) 49 { 50 struct serport *serport = serio->port_data; 51 52 serport->serio->id.type = 0; 53 wake_up_interruptible(&serport->wait); 54 } 55 56 /* 57 * serport_ldisc_open() is the routine that is called upon setting our line 58 * discipline on a tty. It prepares the serio struct. 59 */ 60 61 static int serport_ldisc_open(struct tty_struct *tty) 62 { 63 struct serport *serport; 64 struct serio *serio; 65 char name[64]; 66 67 if (!capable(CAP_SYS_ADMIN)) 68 return -EPERM; 69 70 serport = kmalloc(sizeof(struct serport), GFP_KERNEL); 71 serio = kmalloc(sizeof(struct serio), GFP_KERNEL); 72 if (unlikely(!serport || !serio)) { 73 kfree(serport); 74 kfree(serio); 75 return -ENOMEM; 76 } 77 78 memset(serport, 0, sizeof(struct serport)); 79 serport->serio = serio; 80 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 81 serport->tty = tty; 82 tty->disc_data = serport; 83 84 memset(serio, 0, sizeof(struct serio)); 85 strlcpy(serio->name, "Serial port", sizeof(serio->name)); 86 snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty, name)); 87 serio->id.type = SERIO_RS232; 88 serio->write = serport_serio_write; 89 serio->close = serport_serio_close; 90 serio->port_data = serport; 91 92 init_waitqueue_head(&serport->wait); 93 94 return 0; 95 } 96 97 /* 98 * serport_ldisc_close() is the opposite of serport_ldisc_open() 99 */ 100 101 static void serport_ldisc_close(struct tty_struct *tty) 102 { 103 struct serport *serport = (struct serport*) tty->disc_data; 104 kfree(serport); 105 } 106 107 /* 108 * serport_ldisc_receive() is called by the low level tty driver when characters 109 * are ready for us. We forward the characters, one by one to the 'interrupt' 110 * routine. 111 * 112 * FIXME: We should get pt_regs from the tty layer and forward them to 113 * serio_interrupt here. 114 */ 115 116 static void serport_ldisc_receive(struct tty_struct *tty, const unsigned char *cp, char *fp, int count) 117 { 118 struct serport *serport = (struct serport*) tty->disc_data; 119 int i; 120 for (i = 0; i < count; i++) 121 serio_interrupt(serport->serio, cp[i], 0, NULL); 122 } 123 124 /* 125 * serport_ldisc_room() reports how much room we do have for receiving data. 126 * Although we in fact have infinite room, we need to specify some value 127 * here, and 256 seems to be reasonable. 128 */ 129 130 static int serport_ldisc_room(struct tty_struct *tty) 131 { 132 return 256; 133 } 134 135 /* 136 * serport_ldisc_read() just waits indefinitely if everything goes well. 137 * However, when the serio driver closes the serio port, it finishes, 138 * returning 0 characters. 139 */ 140 141 static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file, unsigned char __user * buf, size_t nr) 142 { 143 struct serport *serport = (struct serport*) tty->disc_data; 144 char name[64]; 145 146 if (test_and_set_bit(SERPORT_BUSY, &serport->flags)) 147 return -EBUSY; 148 149 serio_register_port(serport->serio); 150 printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty, name)); 151 wait_event_interruptible(serport->wait, !serport->serio->id.type); 152 serio_unregister_port(serport->serio); 153 154 clear_bit(SERPORT_BUSY, &serport->flags); 155 156 return 0; 157 } 158 159 /* 160 * serport_ldisc_ioctl() allows to set the port protocol, and device ID 161 */ 162 163 static int serport_ldisc_ioctl(struct tty_struct * tty, struct file * file, unsigned int cmd, unsigned long arg) 164 { 165 struct serport *serport = (struct serport*) tty->disc_data; 166 struct serio *serio = serport->serio; 167 unsigned long type; 168 169 if (cmd == SPIOCSTYPE) { 170 if (get_user(type, (unsigned long __user *) arg)) 171 return -EFAULT; 172 173 serio->id.proto = type & 0x000000ff; 174 serio->id.id = (type & 0x0000ff00) >> 8; 175 serio->id.extra = (type & 0x00ff0000) >> 16; 176 177 return 0; 178 } 179 180 return -EINVAL; 181 } 182 183 static void serport_ldisc_write_wakeup(struct tty_struct * tty) 184 { 185 struct serport *sp = (struct serport *) tty->disc_data; 186 187 serio_drv_write_wakeup(sp->serio); 188 } 189 190 /* 191 * The line discipline structure. 192 */ 193 194 static struct tty_ldisc serport_ldisc = { 195 .owner = THIS_MODULE, 196 .name = "input", 197 .open = serport_ldisc_open, 198 .close = serport_ldisc_close, 199 .read = serport_ldisc_read, 200 .ioctl = serport_ldisc_ioctl, 201 .receive_buf = serport_ldisc_receive, 202 .receive_room = serport_ldisc_room, 203 .write_wakeup = serport_ldisc_write_wakeup 204 }; 205 206 /* 207 * The functions for insering/removing us as a module. 208 */ 209 210 static int __init serport_init(void) 211 { 212 int retval; 213 retval = tty_register_ldisc(N_MOUSE, &serport_ldisc); 214 if (retval) 215 printk(KERN_ERR "serport.c: Error registering line discipline.\n"); 216 217 return retval; 218 } 219 220 static void __exit serport_exit(void) 221 { 222 tty_register_ldisc(N_MOUSE, NULL); 223 } 224 225 module_init(serport_init); 226 module_exit(serport_exit); 227