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
5 * Copyright (c) 2004 Dmitry Torokhov
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.
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/init.h>
19 #include <linux/major.h>
20 #include <linux/device.h>
21 #include <linux/miscdevice.h>
22 #include <linux/wait.h>
23 #include <linux/mutex.h>
25 #define DRIVER_DESC "Raw serio driver"
27 MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
28 MODULE_DESCRIPTION(DRIVER_DESC);
29 MODULE_LICENSE("GPL");
31 #define SERIO_RAW_QUEUE_LEN 64
33 unsigned char queue[SERIO_RAW_QUEUE_LEN];
34 unsigned int tail, head;
39 struct miscdevice dev;
40 wait_queue_head_t wait;
41 struct list_head client_list;
42 struct list_head node;
45 struct serio_raw_client {
46 struct fasync_struct *fasync;
47 struct serio_raw *serio_raw;
48 struct list_head node;
51 static DEFINE_MUTEX(serio_raw_mutex);
52 static LIST_HEAD(serio_raw_list);
53 static unsigned int serio_raw_no;
55 /*********************************************************************
56 * Interface with userspace (file operations) *
57 *********************************************************************/
59 static int serio_raw_fasync(int fd, struct file *file, int on)
61 struct serio_raw_client *client = file->private_data;
63 return fasync_helper(fd, file, on, &client->fasync);
66 static struct serio_raw *serio_raw_locate(int minor)
68 struct serio_raw *serio_raw;
70 list_for_each_entry(serio_raw, &serio_raw_list, node) {
71 if (serio_raw->dev.minor == minor)
78 static int serio_raw_open(struct inode *inode, struct file *file)
80 struct serio_raw *serio_raw;
81 struct serio_raw_client *client;
84 retval = mutex_lock_interruptible(&serio_raw_mutex);
88 serio_raw = serio_raw_locate(iminor(inode));
94 if (!serio_raw->serio) {
99 client = kzalloc(sizeof(struct serio_raw_client), GFP_KERNEL);
105 client->serio_raw = serio_raw;
106 file->private_data = client;
108 kref_get(&serio_raw->kref);
110 serio_pause_rx(serio_raw->serio);
111 list_add_tail(&client->node, &serio_raw->client_list);
112 serio_continue_rx(serio_raw->serio);
115 mutex_unlock(&serio_raw_mutex);
119 static void serio_raw_cleanup(struct kref *kref)
121 struct serio_raw *serio_raw =
122 container_of(kref, struct serio_raw, kref);
124 misc_deregister(&serio_raw->dev);
125 list_del_init(&serio_raw->node);
129 static int serio_raw_release(struct inode *inode, struct file *file)
131 struct serio_raw_client *client = file->private_data;
132 struct serio_raw *serio_raw = client->serio_raw;
134 mutex_lock(&serio_raw_mutex);
136 kref_put(&serio_raw->kref, serio_raw_cleanup);
138 mutex_unlock(&serio_raw_mutex);
142 static bool serio_raw_fetch_byte(struct serio_raw *serio_raw, char *c)
146 serio_pause_rx(serio_raw->serio);
148 empty = serio_raw->head == serio_raw->tail;
150 *c = serio_raw->queue[serio_raw->tail];
151 serio_raw->tail = (serio_raw->tail + 1) % SERIO_RAW_QUEUE_LEN;
154 serio_continue_rx(serio_raw->serio);
159 static ssize_t serio_raw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
161 struct serio_raw_client *client = file->private_data;
162 struct serio_raw *serio_raw = client->serio_raw;
163 char uninitialized_var(c);
166 if (!serio_raw->serio)
169 if (serio_raw->head == serio_raw->tail && (file->f_flags & O_NONBLOCK))
172 retval = wait_event_interruptible(serio_raw->wait,
173 serio_raw->head != serio_raw->tail ||
178 if (!serio_raw->serio)
181 while (retval < count && serio_raw_fetch_byte(serio_raw, &c)) {
182 if (put_user(c, buffer++))
190 static ssize_t serio_raw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
192 struct serio_raw_client *client = file->private_data;
193 struct serio_raw *serio_raw = client->serio_raw;
198 retval = mutex_lock_interruptible(&serio_raw_mutex);
202 if (!serio_raw->serio) {
211 if (get_user(c, buffer++)) {
215 if (serio_write(serio_raw->serio, c)) {
223 mutex_unlock(&serio_raw_mutex);
227 static unsigned int serio_raw_poll(struct file *file, poll_table *wait)
229 struct serio_raw_client *client = file->private_data;
230 struct serio_raw *serio_raw = client->serio_raw;
232 poll_wait(file, &serio_raw->wait, wait);
234 if (serio_raw->head != serio_raw->tail)
235 return POLLIN | POLLRDNORM;
240 static const struct file_operations serio_raw_fops = {
241 .owner = THIS_MODULE,
242 .open = serio_raw_open,
243 .release = serio_raw_release,
244 .read = serio_raw_read,
245 .write = serio_raw_write,
246 .poll = serio_raw_poll,
247 .fasync = serio_raw_fasync,
248 .llseek = noop_llseek,
252 /*********************************************************************
253 * Interface with serio port *
254 *********************************************************************/
256 static irqreturn_t serio_raw_interrupt(struct serio *serio, unsigned char data,
259 struct serio_raw *serio_raw = serio_get_drvdata(serio);
260 struct serio_raw_client *client;
261 unsigned int head = serio_raw->head;
263 /* we are holding serio->lock here so we are protected */
264 serio_raw->queue[head] = data;
265 head = (head + 1) % SERIO_RAW_QUEUE_LEN;
266 if (likely(head != serio_raw->tail)) {
267 serio_raw->head = head;
268 list_for_each_entry(client, &serio_raw->client_list, node)
269 kill_fasync(&client->fasync, SIGIO, POLL_IN);
270 wake_up_interruptible(&serio_raw->wait);
276 static int serio_raw_connect(struct serio *serio, struct serio_driver *drv)
278 struct serio_raw *serio_raw;
281 if (!(serio_raw = kzalloc(sizeof(struct serio_raw), GFP_KERNEL))) {
282 dev_dbg(&serio->dev, "can't allocate memory for a device\n");
286 mutex_lock(&serio_raw_mutex);
288 snprintf(serio_raw->name, sizeof(serio_raw->name), "serio_raw%d", serio_raw_no++);
289 kref_init(&serio_raw->kref);
290 serio_raw->serio = serio;
291 INIT_LIST_HEAD(&serio_raw->client_list);
292 init_waitqueue_head(&serio_raw->wait);
294 serio_set_drvdata(serio, serio_raw);
296 err = serio_open(serio, drv);
300 list_add_tail(&serio_raw->node, &serio_raw_list);
302 serio_raw->dev.minor = PSMOUSE_MINOR;
303 serio_raw->dev.name = serio_raw->name;
304 serio_raw->dev.parent = &serio->dev;
305 serio_raw->dev.fops = &serio_raw_fops;
307 err = misc_register(&serio_raw->dev);
309 serio_raw->dev.minor = MISC_DYNAMIC_MINOR;
310 err = misc_register(&serio_raw->dev);
315 "failed to register raw access device for %s\n",
320 dev_info(&serio->dev, "raw access enabled on %s (%s, minor %d)\n",
321 serio->phys, serio_raw->name, serio_raw->dev.minor);
326 list_del_init(&serio_raw->node);
328 serio_set_drvdata(serio, NULL);
331 mutex_unlock(&serio_raw_mutex);
335 static int serio_raw_reconnect(struct serio *serio)
337 struct serio_raw *serio_raw = serio_get_drvdata(serio);
338 struct serio_driver *drv = serio->drv;
340 if (!drv || !serio_raw) {
342 "reconnect request, but serio is disconnected, ignoring...\n");
347 * Nothing needs to be done here, we just need this method to
348 * keep the same device.
353 static void serio_raw_disconnect(struct serio *serio)
355 struct serio_raw *serio_raw;
357 mutex_lock(&serio_raw_mutex);
359 serio_raw = serio_get_drvdata(serio);
362 serio_set_drvdata(serio, NULL);
364 serio_raw->serio = NULL;
365 wake_up_interruptible(&serio_raw->wait);
366 kref_put(&serio_raw->kref, serio_raw_cleanup);
368 mutex_unlock(&serio_raw_mutex);
371 static struct serio_device_id serio_raw_serio_ids[] = {
379 .type = SERIO_8042_XL,
387 MODULE_DEVICE_TABLE(serio, serio_raw_serio_ids);
389 static struct serio_driver serio_raw_drv = {
393 .description = DRIVER_DESC,
394 .id_table = serio_raw_serio_ids,
395 .interrupt = serio_raw_interrupt,
396 .connect = serio_raw_connect,
397 .reconnect = serio_raw_reconnect,
398 .disconnect = serio_raw_disconnect,
402 static int __init serio_raw_init(void)
404 return serio_register_driver(&serio_raw_drv);
407 static void __exit serio_raw_exit(void)
409 serio_unregister_driver(&serio_raw_drv);
412 module_init(serio_raw_init);
413 module_exit(serio_raw_exit);