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;
46 struct serio_raw_client {
47 struct fasync_struct *fasync;
48 struct serio_raw *serio_raw;
49 struct list_head node;
52 static DEFINE_MUTEX(serio_raw_mutex);
53 static LIST_HEAD(serio_raw_list);
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->dead) {
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_free(struct kref *kref)
121 struct serio_raw *serio_raw =
122 container_of(kref, struct serio_raw, kref);
124 put_device(&serio_raw->serio->dev);
128 static int serio_raw_release(struct inode *inode, struct file *file)
130 struct serio_raw_client *client = file->private_data;
131 struct serio_raw *serio_raw = client->serio_raw;
133 serio_pause_rx(serio_raw->serio);
134 list_del(&client->node);
135 serio_continue_rx(serio_raw->serio);
139 kref_put(&serio_raw->kref, serio_raw_free);
144 static bool serio_raw_fetch_byte(struct serio_raw *serio_raw, char *c)
148 serio_pause_rx(serio_raw->serio);
150 empty = serio_raw->head == serio_raw->tail;
152 *c = serio_raw->queue[serio_raw->tail];
153 serio_raw->tail = (serio_raw->tail + 1) % SERIO_RAW_QUEUE_LEN;
156 serio_continue_rx(serio_raw->serio);
161 static ssize_t serio_raw_read(struct file *file, char __user *buffer,
162 size_t count, loff_t *ppos)
164 struct serio_raw_client *client = file->private_data;
165 struct serio_raw *serio_raw = client->serio_raw;
166 char uninitialized_var(c);
174 if (serio_raw->head == serio_raw->tail &&
175 (file->f_flags & O_NONBLOCK))
181 while (read < count && serio_raw_fetch_byte(serio_raw, &c)) {
182 if (put_user(c, buffer++))
190 if (!(file->f_flags & O_NONBLOCK)) {
191 error = wait_event_interruptible(serio_raw->wait,
192 serio_raw->head != serio_raw->tail ||
202 static ssize_t serio_raw_write(struct file *file, const char __user *buffer,
203 size_t count, loff_t *ppos)
205 struct serio_raw_client *client = file->private_data;
206 struct serio_raw *serio_raw = client->serio_raw;
210 retval = mutex_lock_interruptible(&serio_raw_mutex);
214 if (serio_raw->dead) {
223 if (get_user(c, buffer++)) {
228 if (serio_write(serio_raw->serio, c)) {
229 /* Either signal error or partial write */
239 mutex_unlock(&serio_raw_mutex);
243 static unsigned int serio_raw_poll(struct file *file, poll_table *wait)
245 struct serio_raw_client *client = file->private_data;
246 struct serio_raw *serio_raw = client->serio_raw;
249 poll_wait(file, &serio_raw->wait, wait);
251 mask = serio_raw->dead ? POLLHUP | POLLERR : POLLOUT | POLLWRNORM;
252 if (serio_raw->head != serio_raw->tail)
253 mask |= POLLIN | POLLRDNORM;
258 static const struct file_operations serio_raw_fops = {
259 .owner = THIS_MODULE,
260 .open = serio_raw_open,
261 .release = serio_raw_release,
262 .read = serio_raw_read,
263 .write = serio_raw_write,
264 .poll = serio_raw_poll,
265 .fasync = serio_raw_fasync,
266 .llseek = noop_llseek,
270 /*********************************************************************
271 * Interface with serio port *
272 *********************************************************************/
274 static irqreturn_t serio_raw_interrupt(struct serio *serio, unsigned char data,
277 struct serio_raw *serio_raw = serio_get_drvdata(serio);
278 struct serio_raw_client *client;
279 unsigned int head = serio_raw->head;
281 /* we are holding serio->lock here so we are protected */
282 serio_raw->queue[head] = data;
283 head = (head + 1) % SERIO_RAW_QUEUE_LEN;
284 if (likely(head != serio_raw->tail)) {
285 serio_raw->head = head;
286 list_for_each_entry(client, &serio_raw->client_list, node)
287 kill_fasync(&client->fasync, SIGIO, POLL_IN);
288 wake_up_interruptible(&serio_raw->wait);
294 static int serio_raw_connect(struct serio *serio, struct serio_driver *drv)
296 static atomic_t serio_raw_no = ATOMIC_INIT(0);
297 struct serio_raw *serio_raw;
300 serio_raw = kzalloc(sizeof(struct serio_raw), GFP_KERNEL);
302 dev_dbg(&serio->dev, "can't allocate memory for a device\n");
306 snprintf(serio_raw->name, sizeof(serio_raw->name),
307 "serio_raw%ld", (long)atomic_inc_return(&serio_raw_no) - 1);
308 kref_init(&serio_raw->kref);
309 INIT_LIST_HEAD(&serio_raw->client_list);
310 init_waitqueue_head(&serio_raw->wait);
312 serio_raw->serio = serio;
313 get_device(&serio->dev);
315 serio_set_drvdata(serio, serio_raw);
317 err = serio_open(serio, drv);
321 err = mutex_lock_killable(&serio_raw_mutex);
325 list_add_tail(&serio_raw->node, &serio_raw_list);
326 mutex_unlock(&serio_raw_mutex);
328 serio_raw->dev.minor = PSMOUSE_MINOR;
329 serio_raw->dev.name = serio_raw->name;
330 serio_raw->dev.parent = &serio->dev;
331 serio_raw->dev.fops = &serio_raw_fops;
333 err = misc_register(&serio_raw->dev);
335 serio_raw->dev.minor = MISC_DYNAMIC_MINOR;
336 err = misc_register(&serio_raw->dev);
341 "failed to register raw access device for %s\n",
346 dev_info(&serio->dev, "raw access enabled on %s (%s, minor %d)\n",
347 serio->phys, serio_raw->name, serio_raw->dev.minor);
351 list_del_init(&serio_raw->node);
355 serio_set_drvdata(serio, NULL);
356 kref_put(&serio_raw->kref, serio_raw_free);
360 static int serio_raw_reconnect(struct serio *serio)
362 struct serio_raw *serio_raw = serio_get_drvdata(serio);
363 struct serio_driver *drv = serio->drv;
365 if (!drv || !serio_raw) {
367 "reconnect request, but serio is disconnected, ignoring...\n");
372 * Nothing needs to be done here, we just need this method to
373 * keep the same device.
379 * Wake up users waiting for IO so they can disconnect from
382 static void serio_raw_hangup(struct serio_raw *serio_raw)
384 struct serio_raw_client *client;
386 serio_pause_rx(serio_raw->serio);
387 list_for_each_entry(client, &serio_raw->client_list, node)
388 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
389 serio_continue_rx(serio_raw->serio);
391 wake_up_interruptible(&serio_raw->wait);
395 static void serio_raw_disconnect(struct serio *serio)
397 struct serio_raw *serio_raw = serio_get_drvdata(serio);
399 misc_deregister(&serio_raw->dev);
401 mutex_lock(&serio_raw_mutex);
402 serio_raw->dead = true;
403 list_del_init(&serio_raw->node);
404 mutex_unlock(&serio_raw_mutex);
406 serio_raw_hangup(serio_raw);
409 kref_put(&serio_raw->kref, serio_raw_free);
411 serio_set_drvdata(serio, NULL);
414 static struct serio_device_id serio_raw_serio_ids[] = {
422 .type = SERIO_8042_XL,
430 MODULE_DEVICE_TABLE(serio, serio_raw_serio_ids);
432 static struct serio_driver serio_raw_drv = {
436 .description = DRIVER_DESC,
437 .id_table = serio_raw_serio_ids,
438 .interrupt = serio_raw_interrupt,
439 .connect = serio_raw_connect,
440 .reconnect = serio_raw_reconnect,
441 .disconnect = serio_raw_disconnect,
445 module_serio_driver(serio_raw_drv);