summaryrefslogtreecommitdiffstats
path: root/drivers/input/serio/serio_raw.c
blob: b03009bb74684a2edaf15f6d4f31f7a9904b31bb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
/*
 * Raw serio device providing access to a raw byte stream from underlying
 * serio port. Closely emulates behavior of pre-2.6 /dev/psaux device
 *
 * Copyright (c) 2004 Dmitry Torokhov
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/poll.h>
#include <linux/module.h>
#include <linux/serio.h>
#include <linux/init.h>
#include <linux/major.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
#include <linux/wait.h>
#include <linux/mutex.h>

#define DRIVER_DESC	"Raw serio driver"

MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

#define SERIO_RAW_QUEUE_LEN	64
struct serio_raw {
	unsigned char queue[SERIO_RAW_QUEUE_LEN];
	unsigned int tail, head;

	char name[16];
	unsigned int refcnt;
	struct serio *serio;
	struct miscdevice dev;
	wait_queue_head_t wait;
	struct list_head list;
	struct list_head node;
};

struct serio_raw_list {
	struct fasync_struct *fasync;
	struct serio_raw *serio_raw;
	struct list_head node;
};

static DEFINE_MUTEX(serio_raw_mutex);
static LIST_HEAD(serio_raw_list);
static unsigned int serio_raw_no;

/*********************************************************************
 *             Interface with userspace (file operations)            *
 *********************************************************************/

static int serio_raw_fasync(int fd, struct file *file, int on)
{
	struct serio_raw_list *list = file->private_data;

	return fasync_helper(fd, file, on, &list->fasync);
}

static struct serio_raw *serio_raw_locate(int minor)
{
	struct serio_raw *serio_raw;

	list_for_each_entry(serio_raw, &serio_raw_list, node) {
		if (serio_raw->dev.minor == minor)
			return serio_raw;
	}

	return NULL;
}

static int serio_raw_open(struct inode *inode, struct file *file)
{
	struct serio_raw *serio_raw;
	struct serio_raw_list *list;
	int retval = 0;

	lock_kernel();
	retval = mutex_lock_interruptible(&serio_raw_mutex);
	if (retval)
		goto out_bkl;

	if (!(serio_raw = serio_raw_locate(iminor(inode)))) {
		retval = -ENODEV;
		goto out;
	}

	if (!serio_raw->serio) {
		retval = -ENODEV;
		goto out;
	}

	if (!(list = kzalloc(sizeof(struct serio_raw_list), GFP_KERNEL))) {
		retval = -ENOMEM;
		goto out;
	}

	list->serio_raw = serio_raw;
	file->private_data = list;

	serio_raw->refcnt++;
	list_add_tail(&list->node, &serio_raw->list);

out:
	mutex_unlock(&serio_raw_mutex);
out_bkl:
	unlock_kernel();
	return retval;
}

static int serio_raw_cleanup(struct serio_raw *serio_raw)
{
	if (--serio_raw->refcnt == 0) {
		misc_deregister(&serio_raw->dev);
		list_del_init(&serio_raw->node);
		kfree(serio_raw);

		return 1;
	}

	return 0;
}

static int serio_raw_release(struct inode *inode, struct file *file)
{
	struct serio_raw_list *list = file->private_data;
	struct serio_raw *serio_raw = list->serio_raw;

	mutex_lock(&serio_raw_mutex);

	serio_raw_cleanup(serio_raw);

	mutex_unlock(&serio_raw_mutex);
	return 0;
}

static int serio_raw_fetch_byte(struct serio_raw *serio_raw, char *c)
{
	unsigned long flags;
	int empty;

	spin_lock_irqsave(&serio_raw->serio->lock, flags);

	empty = serio_raw->head == serio_raw->tail;
	if (!empty) {
		*c = serio_raw->queue[serio_raw->tail];
		serio_raw->tail = (serio_raw->tail + 1) % SERIO_RAW_QUEUE_LEN;
	}

	spin_unlock_irqrestore(&serio_raw->serio->lock, flags);

	return !empty;
}

static ssize_t serio_raw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
	struct serio_raw_list *list = file->private_data;
	struct serio_raw *serio_raw = list->serio_raw;
	char uninitialized_var(c);
	ssize_t retval = 0;

	if (!serio_raw->serio)
		return -ENODEV;

	if (serio_raw->head == serio_raw->tail && (file->f_flags & O_NONBLOCK))
		return -EAGAIN;

	retval = wait_event_interruptible(list->serio_raw->wait,
					  serio_raw->head != serio_raw->tail || !serio_raw->serio);
	if (retval)
		return retval;

	if (!serio_raw->serio)
		return -ENODEV;

	while (retval < count && serio_raw_fetch_byte(serio_raw, &c)) {
		if (put_user(c, buffer++))
			return -EFAULT;
		retval++;
	}

	return retval;
}

static ssize_t serio_raw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
	struct serio_raw_list *list = file->private_data;
	ssize_t written = 0;
	int retval;
	unsigned char c;

	retval = mutex_lock_interruptible(&serio_raw_mutex);
	if (retval)
		return retval;

	if (!list->serio_raw->serio) {
		retval = -ENODEV;
		goto out;
	}

	if (count > 32)
		count = 32;

	while (count--) {
		if (get_user(c, buffer++)) {
			retval = -EFAULT;
			goto out;
		}
		if (serio_write(list->serio_raw->serio, c)) {
			retval = -EIO;
			goto out;
		}
		written++;
	};

out:
	mutex_unlock(&serio_raw_mutex);
	return written;
}

static unsigned int serio_raw_poll(struct file *file, poll_table *wait)
{
	struct serio_raw_list *list = file->private_data;

	poll_wait(file, &list->serio_raw->wait, wait);

	if (list->serio_raw->head != list->serio_raw->tail)
		return POLLIN | POLLRDNORM;

	return 0;
}

static const struct file_operations serio_raw_fops = {
	.owner =	THIS_MODULE,
	.open =		serio_raw_open,
	.release =	serio_raw_release,
	.read =		serio_raw_read,
	.write =	serio_raw_write,
	.poll =		serio_raw_poll,
	.fasync =	serio_raw_fasync,
};


/*********************************************************************
 *                   Interface with serio port   	             *
 *********************************************************************/

static irqreturn_t serio_raw_interrupt(struct serio *serio, unsigned char data,
					unsigned int dfl)
{
	struct serio_raw *serio_raw = serio_get_drvdata(serio);
	struct serio_raw_list *list;
	unsigned int head = serio_raw->head;

	/* we are holding serio->lock here so we are prootected */
	serio_raw->queue[head] = data;
	head = (head + 1) % SERIO_RAW_QUEUE_LEN;
	if (likely(head != serio_raw->tail)) {
		serio_raw->head = head;
		list_for_each_entry(list, &serio_raw->list, node)
			kill_fasync(&list->fasync, SIGIO, POLL_IN);
		wake_up_interruptible(&serio_raw->wait);
	}

	return IRQ_HANDLED;
}

static int serio_raw_connect(struct serio *serio, struct serio_driver *drv)
{
	struct serio_raw *serio_raw;
	int err;

	if (!(serio_raw = kzalloc(sizeof(struct serio_raw), GFP_KERNEL))) {
		printk(KERN_ERR "serio_raw.c: can't allocate memory for a device\n");
		return -ENOMEM;
	}

	mutex_lock(&serio_raw_mutex);

	snprintf(serio_raw->name, sizeof(serio_raw->name), "serio_raw%d", serio_raw_no++);
	serio_raw->refcnt = 1;
	serio_raw->serio = serio;
	INIT_LIST_HEAD(&serio_raw->list);
	init_waitqueue_head(&serio_raw->wait);

	serio_set_drvdata(serio, serio_raw);

	err = serio_open(serio, drv);
	if (err)
		goto out_free;

	list_add_tail(&serio_raw->node, &serio_raw_list);

	serio_raw->dev.minor = PSMOUSE_MINOR;
	serio_raw->dev.name = serio_raw->name;
	serio_raw->dev.parent = &serio->dev;
	serio_raw->dev.fops = &serio_raw_fops;

	err = misc_register(&serio_raw->dev);
	if (err) {
		serio_raw->dev.minor = MISC_DYNAMIC_MINOR;
		err = misc_register(&serio_raw->dev);
	}

	if (err) {
		printk(KERN_INFO "serio_raw: failed to register raw access device for %s\n",
			serio->phys);
		goto out_close;
	}

	printk(KERN_INFO "serio_raw: raw access enabled on %s (%s, minor %d)\n",
		serio->phys, serio_raw->name, serio_raw->dev.minor);
	goto out;

out_close:
	serio_close(serio);
	list_del_init(&serio_raw->node);
out_free:
	serio_set_drvdata(serio, NULL);
	kfree(serio_raw);
out:
	mutex_unlock(&serio_raw_mutex);
	return err;
}

static int serio_raw_reconnect(struct serio *serio)
{
	struct serio_raw *serio_raw = serio_get_drvdata(serio);
	struct serio_driver *drv = serio->drv;

	if (!drv || !serio_raw) {
		printk(KERN_DEBUG "serio_raw: reconnect request, but serio is disconnected, ignoring...\n");
		return -1;
	}

	/*
	 * Nothing needs to be done here, we just need this method to
	 * keep the same device.
	 */
	return 0;
}

static void serio_raw_disconnect(struct serio *serio)
{
	struct serio_raw *serio_raw;

	mutex_lock(&serio_raw_mutex);

	serio_raw = serio_get_drvdata(serio);

	serio_close(serio);
	serio_set_drvdata(serio, NULL);

	serio_raw->serio = NULL;
	if (!serio_raw_cleanup(serio_raw))
		wake_up_interruptible(&serio_raw->wait);

	mutex_unlock(&serio_raw_mutex);
}

static struct serio_device_id serio_raw_serio_ids[] = {
	{
		.type	= SERIO_8042,
		.proto	= SERIO_ANY,
		.id	= SERIO_ANY,
		.extra	= SERIO_ANY,
	},
	{
		.type	= SERIO_8042_XL,
		.proto	= SERIO_ANY,
		.id	= SERIO_ANY,
		.extra	= SERIO_ANY,
	},
	{ 0 }
};

MODULE_DEVICE_TABLE(serio, serio_raw_serio_ids);

static struct serio_driver serio_raw_drv = {
	.driver		= {
		.name	= "serio_raw",
	},
	.description	= DRIVER_DESC,
	.id_table	= serio_raw_serio_ids,
	.interrupt	= serio_raw_interrupt,
	.connect	= serio_raw_connect,
	.reconnect	= serio_raw_reconnect,
	.disconnect	= serio_raw_disconnect,
	.manual_bind	= 1,
};

static int __init serio_raw_init(void)
{
	return serio_register_driver(&serio_raw_drv);
}

static void __exit serio_raw_exit(void)
{
	serio_unregister_driver(&serio_raw_drv);
}

module_init(serio_raw_init);
module_exit(serio_raw_exit);