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
26MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
27MODULE_DESCRIPTION("Input device TTY line discipline");
28MODULE_LICENSE("GPL");
29MODULE_ALIAS_LDISC(N_MOUSE);
30
31#define SERPORT_BUSY	1
32#define SERPORT_ACTIVE	2
33#define SERPORT_DEAD	3
34
35struct 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
48static 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
54static 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
67static 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
85static 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
111static 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
124static 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
156out:
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
166static 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
202static 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
215static 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)
233static 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
252static 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
267static 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
285static 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
295static void __exit serport_exit(void)
296{
297	tty_unregister_ldisc(N_MOUSE);
298}
299
300module_init(serport_init);
301module_exit(serport_exit);
302