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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/slab.h>
13 #include <linux/poll.h>
14 #include <linux/module.h>
15 #include <linux/serio.h>
16 #include <linux/init.h>
17 #include <linux/major.h>
18 #include <linux/device.h>
19 #include <linux/devfs_fs_kernel.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
26 MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
27 MODULE_DESCRIPTION(DRIVER_DESC);
28 MODULE_LICENSE("GPL");
29
30 #define SERIO_RAW_QUEUE_LEN 64
31 struct serio_raw {
32 unsigned char queue[SERIO_RAW_QUEUE_LEN];
33 unsigned int tail, head;
34
35 char name[16];
36 unsigned int refcnt;
37 struct serio *serio;
38 struct miscdevice dev;
39 wait_queue_head_t wait;
40 struct list_head list;
41 struct list_head node;
42 };
43
44 struct serio_raw_list {
45 struct fasync_struct *fasync;
46 struct serio_raw *serio_raw;
47 struct list_head node;
48 };
49
50 static DEFINE_MUTEX(serio_raw_mutex);
51 static LIST_HEAD(serio_raw_list);
52 static unsigned int serio_raw_no;
53
54 /*********************************************************************
55 * Interface with userspace (file operations) *
56 *********************************************************************/
57
58 static int serio_raw_fasync(int fd, struct file *file, int on)
59 {
60 struct serio_raw_list *list = file->private_data;
61 int retval;
62
63 retval = fasync_helper(fd, file, on, &list->fasync);
64 return retval < 0 ? retval : 0;
65 }
66
67 static struct serio_raw *serio_raw_locate(int minor)
68 {
69 struct serio_raw *serio_raw;
70
71 list_for_each_entry(serio_raw, &serio_raw_list, node) {
72 if (serio_raw->dev.minor == minor)
73 return serio_raw;
74 }
75
76 return NULL;
77 }
78
79 static int serio_raw_open(struct inode *inode, struct file *file)
80 {
81 struct serio_raw *serio_raw;
82 struct serio_raw_list *list;
83 int retval = 0;
84
85 retval = mutex_lock_interruptible(&serio_raw_mutex);
86 if (retval)
87 return retval;
88
89 if (!(serio_raw = serio_raw_locate(iminor(inode)))) {
90 retval = -ENODEV;
91 goto out;
92 }
93
94 if (!serio_raw->serio) {
95 retval = -ENODEV;
96 goto out;
97 }
98
99 if (!(list = kzalloc(sizeof(struct serio_raw_list), GFP_KERNEL))) {
100 retval = -ENOMEM;
101 goto out;
102 }
103
104 list->serio_raw = serio_raw;
105 file->private_data = list;
106
107 serio_raw->refcnt++;
108 list_add_tail(&list->node, &serio_raw->list);
109
110 out:
111 mutex_unlock(&serio_raw_mutex);
112 return retval;
113 }
114
115 static int serio_raw_cleanup(struct serio_raw *serio_raw)
116 {
117 if (--serio_raw->refcnt == 0) {
118 misc_deregister(&serio_raw->dev);
119 list_del_init(&serio_raw->node);
120 kfree(serio_raw);
121
122 return 1;
123 }
124
125 return 0;
126 }
127
128 static int serio_raw_release(struct inode *inode, struct file *file)
129 {
130 struct serio_raw_list *list = file->private_data;
131 struct serio_raw *serio_raw = list->serio_raw;
132
133 mutex_lock(&serio_raw_mutex);
134
135 serio_raw_fasync(-1, file, 0);
136 serio_raw_cleanup(serio_raw);
137
138 mutex_unlock(&serio_raw_mutex);
139 return 0;
140 }
141
142 static int serio_raw_fetch_byte(struct serio_raw *serio_raw, char *c)
143 {
144 unsigned long flags;
145 int empty;
146
147 spin_lock_irqsave(&serio_raw->serio->lock, flags);
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 spin_unlock_irqrestore(&serio_raw->serio->lock, flags);
156
157 return !empty;
158 }
159
160 static ssize_t serio_raw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
161 {
162 struct serio_raw_list *list = file->private_data;
163 struct serio_raw *serio_raw = list->serio_raw;
164 char c;
165 ssize_t retval = 0;
166
167 if (!serio_raw->serio)
168 return -ENODEV;
169
170 if (serio_raw->head == serio_raw->tail && (file->f_flags & O_NONBLOCK))
171 return -EAGAIN;
172
173 retval = wait_event_interruptible(list->serio_raw->wait,
174 serio_raw->head != serio_raw->tail || !serio_raw->serio);
175 if (retval)
176 return retval;
177
178 if (!serio_raw->serio)
179 return -ENODEV;
180
181 while (retval < count && serio_raw_fetch_byte(serio_raw, &c)) {
182 if (put_user(c, buffer++))
183 return -EFAULT;
184 retval++;
185 }
186
187 return retval;
188 }
189
190 static ssize_t serio_raw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
191 {
192 struct serio_raw_list *list = file->private_data;
193 ssize_t written = 0;
194 int retval;
195 unsigned char c;
196
197 retval = mutex_lock_interruptible(&serio_raw_mutex);
198 if (retval)
199 return retval;
200
201 if (!list->serio_raw->serio) {
202 retval = -ENODEV;
203 goto out;
204 }
205
206 if (count > 32)
207 count = 32;
208
209 while (count--) {
210 if (get_user(c, buffer++)) {
211 retval = -EFAULT;
212 goto out;
213 }
214 if (serio_write(list->serio_raw->serio, c)) {
215 retval = -EIO;
216 goto out;
217 }
218 written++;
219 };
220
221 out:
222 mutex_unlock(&serio_raw_mutex);
223 return written;
224 }
225
226 static unsigned int serio_raw_poll(struct file *file, poll_table *wait)
227 {
228 struct serio_raw_list *list = file->private_data;
229
230 poll_wait(file, &list->serio_raw->wait, wait);
231
232 if (list->serio_raw->head != list->serio_raw->tail)
233 return POLLIN | POLLRDNORM;
234
235 return 0;
236 }
237
238 static struct file_operations serio_raw_fops = {
239 .owner = THIS_MODULE,
240 .open = serio_raw_open,
241 .release = serio_raw_release,
242 .read = serio_raw_read,
243 .write = serio_raw_write,
244 .poll = serio_raw_poll,
245 .fasync = serio_raw_fasync,
246 };
247
248
249 /*********************************************************************
250 * Interface with serio port *
251 *********************************************************************/
252
253 static irqreturn_t serio_raw_interrupt(struct serio *serio, unsigned char data,
254 unsigned int dfl, struct pt_regs *regs)
255 {
256 struct serio_raw *serio_raw = serio_get_drvdata(serio);
257 struct serio_raw_list *list;
258 unsigned int head = serio_raw->head;
259
260 /* we are holding serio->lock here so we are prootected */
261 serio_raw->queue[head] = data;
262 head = (head + 1) % SERIO_RAW_QUEUE_LEN;
263 if (likely(head != serio_raw->tail)) {
264 serio_raw->head = head;
265 list_for_each_entry(list, &serio_raw->list, node)
266 kill_fasync(&list->fasync, SIGIO, POLL_IN);
267 wake_up_interruptible(&serio_raw->wait);
268 }
269
270 return IRQ_HANDLED;
271 }
272
273 static int serio_raw_connect(struct serio *serio, struct serio_driver *drv)
274 {
275 struct serio_raw *serio_raw;
276 int err;
277
278 if (!(serio_raw = kzalloc(sizeof(struct serio_raw), GFP_KERNEL))) {
279 printk(KERN_ERR "serio_raw.c: can't allocate memory for a device\n");
280 return -ENOMEM;
281 }
282
283 mutex_lock(&serio_raw_mutex);
284
285 snprintf(serio_raw->name, sizeof(serio_raw->name), "serio_raw%d", serio_raw_no++);
286 serio_raw->refcnt = 1;
287 serio_raw->serio = serio;
288 INIT_LIST_HEAD(&serio_raw->list);
289 init_waitqueue_head(&serio_raw->wait);
290
291 serio_set_drvdata(serio, serio_raw);
292
293 err = serio_open(serio, drv);
294 if (err)
295 goto out_free;
296
297 list_add_tail(&serio_raw->node, &serio_raw_list);
298
299 serio_raw->dev.minor = PSMOUSE_MINOR;
300 serio_raw->dev.name = serio_raw->name;
301 serio_raw->dev.dev = &serio->dev;
302 serio_raw->dev.fops = &serio_raw_fops;
303
304 err = misc_register(&serio_raw->dev);
305 if (err) {
306 serio_raw->dev.minor = MISC_DYNAMIC_MINOR;
307 err = misc_register(&serio_raw->dev);
308 }
309
310 if (err) {
311 printk(KERN_INFO "serio_raw: failed to register raw access device for %s\n",
312 serio->phys);
313 goto out_close;
314 }
315
316 printk(KERN_INFO "serio_raw: raw access enabled on %s (%s, minor %d)\n",
317 serio->phys, serio_raw->name, serio_raw->dev.minor);
318 goto out;
319
320 out_close:
321 serio_close(serio);
322 list_del_init(&serio_raw->node);
323 out_free:
324 serio_set_drvdata(serio, NULL);
325 kfree(serio_raw);
326 out:
327 mutex_unlock(&serio_raw_mutex);
328 return err;
329 }
330
331 static int serio_raw_reconnect(struct serio *serio)
332 {
333 struct serio_raw *serio_raw = serio_get_drvdata(serio);
334 struct serio_driver *drv = serio->drv;
335
336 if (!drv || !serio_raw) {
337 printk(KERN_DEBUG "serio_raw: reconnect request, but serio is disconnected, ignoring...\n");
338 return -1;
339 }
340
341 /*
342 * Nothing needs to be done here, we just need this method to
343 * keep the same device.
344 */
345 return 0;
346 }
347
348 static void serio_raw_disconnect(struct serio *serio)
349 {
350 struct serio_raw *serio_raw;
351
352 mutex_lock(&serio_raw_mutex);
353
354 serio_raw = serio_get_drvdata(serio);
355
356 serio_close(serio);
357 serio_set_drvdata(serio, NULL);
358
359 serio_raw->serio = NULL;
360 if (!serio_raw_cleanup(serio_raw))
361 wake_up_interruptible(&serio_raw->wait);
362
363 mutex_unlock(&serio_raw_mutex);
364 }
365
366 static struct serio_device_id serio_raw_serio_ids[] = {
367 {
368 .type = SERIO_8042,
369 .proto = SERIO_ANY,
370 .id = SERIO_ANY,
371 .extra = SERIO_ANY,
372 },
373 { 0 }
374 };
375
376 MODULE_DEVICE_TABLE(serio, serio_raw_serio_ids);
377
378 static struct serio_driver serio_raw_drv = {
379 .driver = {
380 .name = "serio_raw",
381 },
382 .description = DRIVER_DESC,
383 .id_table = serio_raw_serio_ids,
384 .interrupt = serio_raw_interrupt,
385 .connect = serio_raw_connect,
386 .reconnect = serio_raw_reconnect,
387 .disconnect = serio_raw_disconnect,
388 .manual_bind = 1,
389 };
390
391 static int __init serio_raw_init(void)
392 {
393 serio_register_driver(&serio_raw_drv);
394 return 0;
395 }
396
397 static void __exit serio_raw_exit(void)
398 {
399 serio_unregister_driver(&serio_raw_drv);
400 }
401
402 module_init(serio_raw_init);
403 module_exit(serio_raw_exit);