[go: nahoru, domu]
1/*
2 * Raw serio device providing access to a raw byte stream from underlying
3 * serio port. Closely emulates behavior of pre-2.6 /dev/psaux device
4 *
5 * Copyright (c) 2004 Dmitry Torokhov
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 as published by
9 * the Free Software Foundation.
10 */
11
12#include <linux/kref.h>
13#include <linux/sched.h>
14#include <linux/slab.h>
15#include <linux/poll.h>
16#include <linux/module.h>
17#include <linux/serio.h>
18#include <linux/major.h>
19#include <linux/device.h>
20#include <linux/miscdevice.h>
21#include <linux/wait.h>
22#include <linux/mutex.h>
23
24#define DRIVER_DESC	"Raw serio driver"
25
26MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
27MODULE_DESCRIPTION(DRIVER_DESC);
28MODULE_LICENSE("GPL");
29
30#define SERIO_RAW_QUEUE_LEN	64
31struct serio_raw {
32	unsigned char queue[SERIO_RAW_QUEUE_LEN];
33	unsigned int tail, head;
34
35	char name[16];
36	struct kref kref;
37	struct serio *serio;
38	struct miscdevice dev;
39	wait_queue_head_t wait;
40	struct list_head client_list;
41	struct list_head node;
42	bool dead;
43};
44
45struct serio_raw_client {
46	struct fasync_struct *fasync;
47	struct serio_raw *serio_raw;
48	struct list_head node;
49};
50
51static DEFINE_MUTEX(serio_raw_mutex);
52static LIST_HEAD(serio_raw_list);
53
54/*********************************************************************
55 *             Interface with userspace (file operations)            *
56 *********************************************************************/
57
58static int serio_raw_fasync(int fd, struct file *file, int on)
59{
60	struct serio_raw_client *client = file->private_data;
61
62	return fasync_helper(fd, file, on, &client->fasync);
63}
64
65static struct serio_raw *serio_raw_locate(int minor)
66{
67	struct serio_raw *serio_raw;
68
69	list_for_each_entry(serio_raw, &serio_raw_list, node) {
70		if (serio_raw->dev.minor == minor)
71			return serio_raw;
72	}
73
74	return NULL;
75}
76
77static int serio_raw_open(struct inode *inode, struct file *file)
78{
79	struct serio_raw *serio_raw;
80	struct serio_raw_client *client;
81	int retval;
82
83	retval = mutex_lock_interruptible(&serio_raw_mutex);
84	if (retval)
85		return retval;
86
87	serio_raw = serio_raw_locate(iminor(inode));
88	if (!serio_raw) {
89		retval = -ENODEV;
90		goto out;
91	}
92
93	if (serio_raw->dead) {
94		retval = -ENODEV;
95		goto out;
96	}
97
98	client = kzalloc(sizeof(struct serio_raw_client), GFP_KERNEL);
99	if (!client) {
100		retval = -ENOMEM;
101		goto out;
102	}
103
104	client->serio_raw = serio_raw;
105	file->private_data = client;
106
107	kref_get(&serio_raw->kref);
108
109	serio_pause_rx(serio_raw->serio);
110	list_add_tail(&client->node, &serio_raw->client_list);
111	serio_continue_rx(serio_raw->serio);
112
113out:
114	mutex_unlock(&serio_raw_mutex);
115	return retval;
116}
117
118static void serio_raw_free(struct kref *kref)
119{
120	struct serio_raw *serio_raw =
121			container_of(kref, struct serio_raw, kref);
122
123	put_device(&serio_raw->serio->dev);
124	kfree(serio_raw);
125}
126
127static int serio_raw_release(struct inode *inode, struct file *file)
128{
129	struct serio_raw_client *client = file->private_data;
130	struct serio_raw *serio_raw = client->serio_raw;
131
132	serio_pause_rx(serio_raw->serio);
133	list_del(&client->node);
134	serio_continue_rx(serio_raw->serio);
135
136	kfree(client);
137
138	kref_put(&serio_raw->kref, serio_raw_free);
139
140	return 0;
141}
142
143static bool serio_raw_fetch_byte(struct serio_raw *serio_raw, char *c)
144{
145	bool empty;
146
147	serio_pause_rx(serio_raw->serio);
148
149	empty = serio_raw->head == serio_raw->tail;
150	if (!empty) {
151		*c = serio_raw->queue[serio_raw->tail];
152		serio_raw->tail = (serio_raw->tail + 1) % SERIO_RAW_QUEUE_LEN;
153	}
154
155	serio_continue_rx(serio_raw->serio);
156
157	return !empty;
158}
159
160static ssize_t serio_raw_read(struct file *file, char __user *buffer,
161			      size_t count, loff_t *ppos)
162{
163	struct serio_raw_client *client = file->private_data;
164	struct serio_raw *serio_raw = client->serio_raw;
165	char uninitialized_var(c);
166	ssize_t read = 0;
167	int error;
168
169	for (;;) {
170		if (serio_raw->dead)
171			return -ENODEV;
172
173		if (serio_raw->head == serio_raw->tail &&
174		    (file->f_flags & O_NONBLOCK))
175			return -EAGAIN;
176
177		if (count == 0)
178			break;
179
180		while (read < count && serio_raw_fetch_byte(serio_raw, &c)) {
181			if (put_user(c, buffer++))
182				return -EFAULT;
183			read++;
184		}
185
186		if (read)
187			break;
188
189		if (!(file->f_flags & O_NONBLOCK)) {
190			error = wait_event_interruptible(serio_raw->wait,
191					serio_raw->head != serio_raw->tail ||
192					serio_raw->dead);
193			if (error)
194				return error;
195		}
196	}
197
198	return read;
199}
200
201static ssize_t serio_raw_write(struct file *file, const char __user *buffer,
202			       size_t count, loff_t *ppos)
203{
204	struct serio_raw_client *client = file->private_data;
205	struct serio_raw *serio_raw = client->serio_raw;
206	int retval = 0;
207	unsigned char c;
208
209	retval = mutex_lock_interruptible(&serio_raw_mutex);
210	if (retval)
211		return retval;
212
213	if (serio_raw->dead) {
214		retval = -ENODEV;
215		goto out;
216	}
217
218	if (count > 32)
219		count = 32;
220
221	while (count--) {
222		if (get_user(c, buffer++)) {
223			retval = -EFAULT;
224			goto out;
225		}
226
227		if (serio_write(serio_raw->serio, c)) {
228			/* Either signal error or partial write */
229			if (retval == 0)
230				retval = -EIO;
231			goto out;
232		}
233
234		retval++;
235	}
236
237out:
238	mutex_unlock(&serio_raw_mutex);
239	return retval;
240}
241
242static unsigned int serio_raw_poll(struct file *file, poll_table *wait)
243{
244	struct serio_raw_client *client = file->private_data;
245	struct serio_raw *serio_raw = client->serio_raw;
246	unsigned int mask;
247
248	poll_wait(file, &serio_raw->wait, wait);
249
250	mask = serio_raw->dead ? POLLHUP | POLLERR : POLLOUT | POLLWRNORM;
251	if (serio_raw->head != serio_raw->tail)
252		mask |= POLLIN | POLLRDNORM;
253
254	return mask;
255}
256
257static const struct file_operations serio_raw_fops = {
258	.owner		= THIS_MODULE,
259	.open		= serio_raw_open,
260	.release	= serio_raw_release,
261	.read		= serio_raw_read,
262	.write		= serio_raw_write,
263	.poll		= serio_raw_poll,
264	.fasync		= serio_raw_fasync,
265	.llseek		= noop_llseek,
266};
267
268
269/*********************************************************************
270 *                   Interface with serio port                       *
271 *********************************************************************/
272
273static irqreturn_t serio_raw_interrupt(struct serio *serio, unsigned char data,
274					unsigned int dfl)
275{
276	struct serio_raw *serio_raw = serio_get_drvdata(serio);
277	struct serio_raw_client *client;
278	unsigned int head = serio_raw->head;
279
280	/* we are holding serio->lock here so we are protected */
281	serio_raw->queue[head] = data;
282	head = (head + 1) % SERIO_RAW_QUEUE_LEN;
283	if (likely(head != serio_raw->tail)) {
284		serio_raw->head = head;
285		list_for_each_entry(client, &serio_raw->client_list, node)
286			kill_fasync(&client->fasync, SIGIO, POLL_IN);
287		wake_up_interruptible(&serio_raw->wait);
288	}
289
290	return IRQ_HANDLED;
291}
292
293static int serio_raw_connect(struct serio *serio, struct serio_driver *drv)
294{
295	static atomic_t serio_raw_no = ATOMIC_INIT(0);
296	struct serio_raw *serio_raw;
297	int err;
298
299	serio_raw = kzalloc(sizeof(struct serio_raw), GFP_KERNEL);
300	if (!serio_raw) {
301		dev_dbg(&serio->dev, "can't allocate memory for a device\n");
302		return -ENOMEM;
303	}
304
305	snprintf(serio_raw->name, sizeof(serio_raw->name),
306		 "serio_raw%ld", (long)atomic_inc_return(&serio_raw_no) - 1);
307	kref_init(&serio_raw->kref);
308	INIT_LIST_HEAD(&serio_raw->client_list);
309	init_waitqueue_head(&serio_raw->wait);
310
311	serio_raw->serio = serio;
312	get_device(&serio->dev);
313
314	serio_set_drvdata(serio, serio_raw);
315
316	err = serio_open(serio, drv);
317	if (err)
318		goto err_free;
319
320	err = mutex_lock_killable(&serio_raw_mutex);
321	if (err)
322		goto err_close;
323
324	list_add_tail(&serio_raw->node, &serio_raw_list);
325	mutex_unlock(&serio_raw_mutex);
326
327	serio_raw->dev.minor = PSMOUSE_MINOR;
328	serio_raw->dev.name = serio_raw->name;
329	serio_raw->dev.parent = &serio->dev;
330	serio_raw->dev.fops = &serio_raw_fops;
331
332	err = misc_register(&serio_raw->dev);
333	if (err) {
334		serio_raw->dev.minor = MISC_DYNAMIC_MINOR;
335		err = misc_register(&serio_raw->dev);
336	}
337
338	if (err) {
339		dev_err(&serio->dev,
340			"failed to register raw access device for %s\n",
341			serio->phys);
342		goto err_unlink;
343	}
344
345	dev_info(&serio->dev, "raw access enabled on %s (%s, minor %d)\n",
346		 serio->phys, serio_raw->name, serio_raw->dev.minor);
347	return 0;
348
349err_unlink:
350	list_del_init(&serio_raw->node);
351err_close:
352	serio_close(serio);
353err_free:
354	serio_set_drvdata(serio, NULL);
355	kref_put(&serio_raw->kref, serio_raw_free);
356	return err;
357}
358
359static int serio_raw_reconnect(struct serio *serio)
360{
361	struct serio_raw *serio_raw = serio_get_drvdata(serio);
362	struct serio_driver *drv = serio->drv;
363
364	if (!drv || !serio_raw) {
365		dev_dbg(&serio->dev,
366			"reconnect request, but serio is disconnected, ignoring...\n");
367		return -1;
368	}
369
370	/*
371	 * Nothing needs to be done here, we just need this method to
372	 * keep the same device.
373	 */
374	return 0;
375}
376
377/*
378 * Wake up users waiting for IO so they can disconnect from
379 * dead device.
380 */
381static void serio_raw_hangup(struct serio_raw *serio_raw)
382{
383	struct serio_raw_client *client;
384
385	serio_pause_rx(serio_raw->serio);
386	list_for_each_entry(client, &serio_raw->client_list, node)
387		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
388	serio_continue_rx(serio_raw->serio);
389
390	wake_up_interruptible(&serio_raw->wait);
391}
392
393
394static void serio_raw_disconnect(struct serio *serio)
395{
396	struct serio_raw *serio_raw = serio_get_drvdata(serio);
397
398	misc_deregister(&serio_raw->dev);
399
400	mutex_lock(&serio_raw_mutex);
401	serio_raw->dead = true;
402	list_del_init(&serio_raw->node);
403	mutex_unlock(&serio_raw_mutex);
404
405	serio_raw_hangup(serio_raw);
406
407	serio_close(serio);
408	kref_put(&serio_raw->kref, serio_raw_free);
409
410	serio_set_drvdata(serio, NULL);
411}
412
413static struct serio_device_id serio_raw_serio_ids[] = {
414	{
415		.type	= SERIO_8042,
416		.proto	= SERIO_ANY,
417		.id	= SERIO_ANY,
418		.extra	= SERIO_ANY,
419	},
420	{
421		.type	= SERIO_8042_XL,
422		.proto	= SERIO_ANY,
423		.id	= SERIO_ANY,
424		.extra	= SERIO_ANY,
425	},
426	{ 0 }
427};
428
429MODULE_DEVICE_TABLE(serio, serio_raw_serio_ids);
430
431static struct serio_driver serio_raw_drv = {
432	.driver		= {
433		.name	= "serio_raw",
434	},
435	.description	= DRIVER_DESC,
436	.id_table	= serio_raw_serio_ids,
437	.interrupt	= serio_raw_interrupt,
438	.connect	= serio_raw_connect,
439	.reconnect	= serio_raw_reconnect,
440	.disconnect	= serio_raw_disconnect,
441	.manual_bind	= true,
442};
443
444module_serio_driver(serio_raw_drv);
445