HID: uhid: forward open/close events to user-space
[linux-2.6.git] / drivers / hid / uhid.c
1 /*
2  * User-space I/O driver support for HID subsystem
3  * Copyright (c) 2012 David Herrmann
4  */
5
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 as published by the Free
9  * Software Foundation; either version 2 of the License, or (at your option)
10  * any later version.
11  */
12
13 #include <linux/atomic.h>
14 #include <linux/device.h>
15 #include <linux/fs.h>
16 #include <linux/hid.h>
17 #include <linux/input.h>
18 #include <linux/miscdevice.h>
19 #include <linux/module.h>
20 #include <linux/mutex.h>
21 #include <linux/poll.h>
22 #include <linux/sched.h>
23 #include <linux/spinlock.h>
24 #include <linux/uhid.h>
25 #include <linux/wait.h>
26
27 #define UHID_NAME       "uhid"
28 #define UHID_BUFSIZE    32
29
30 struct uhid_device {
31         struct mutex devlock;
32         bool running;
33
34         __u8 *rd_data;
35         uint rd_size;
36
37         struct hid_device *hid;
38         struct uhid_event input_buf;
39
40         wait_queue_head_t waitq;
41         spinlock_t qlock;
42         __u8 head;
43         __u8 tail;
44         struct uhid_event *outq[UHID_BUFSIZE];
45 };
46
47 static struct miscdevice uhid_misc;
48
49 static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev)
50 {
51         __u8 newhead;
52
53         newhead = (uhid->head + 1) % UHID_BUFSIZE;
54
55         if (newhead != uhid->tail) {
56                 uhid->outq[uhid->head] = ev;
57                 uhid->head = newhead;
58                 wake_up_interruptible(&uhid->waitq);
59         } else {
60                 hid_warn(uhid->hid, "Output queue is full\n");
61                 kfree(ev);
62         }
63 }
64
65 static int uhid_queue_event(struct uhid_device *uhid, __u32 event)
66 {
67         unsigned long flags;
68         struct uhid_event *ev;
69
70         ev = kzalloc(sizeof(*ev), GFP_KERNEL);
71         if (!ev)
72                 return -ENOMEM;
73
74         ev->type = event;
75
76         spin_lock_irqsave(&uhid->qlock, flags);
77         uhid_queue(uhid, ev);
78         spin_unlock_irqrestore(&uhid->qlock, flags);
79
80         return 0;
81 }
82
83 static int uhid_hid_start(struct hid_device *hid)
84 {
85         struct uhid_device *uhid = hid->driver_data;
86
87         return uhid_queue_event(uhid, UHID_START);
88 }
89
90 static void uhid_hid_stop(struct hid_device *hid)
91 {
92         struct uhid_device *uhid = hid->driver_data;
93
94         hid->claimed = 0;
95         uhid_queue_event(uhid, UHID_STOP);
96 }
97
98 static int uhid_hid_open(struct hid_device *hid)
99 {
100         struct uhid_device *uhid = hid->driver_data;
101
102         return uhid_queue_event(uhid, UHID_OPEN);
103 }
104
105 static void uhid_hid_close(struct hid_device *hid)
106 {
107         struct uhid_device *uhid = hid->driver_data;
108
109         uhid_queue_event(uhid, UHID_CLOSE);
110 }
111
112 static int uhid_hid_input(struct input_dev *input, unsigned int type,
113                           unsigned int code, int value)
114 {
115         return 0;
116 }
117
118 static int uhid_hid_parse(struct hid_device *hid)
119 {
120         struct uhid_device *uhid = hid->driver_data;
121
122         return hid_parse_report(hid, uhid->rd_data, uhid->rd_size);
123 }
124
125 static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum,
126                             __u8 *buf, size_t count, unsigned char rtype)
127 {
128         return 0;
129 }
130
131 static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
132                                unsigned char report_type)
133 {
134         return 0;
135 }
136
137 static struct hid_ll_driver uhid_hid_driver = {
138         .start = uhid_hid_start,
139         .stop = uhid_hid_stop,
140         .open = uhid_hid_open,
141         .close = uhid_hid_close,
142         .hidinput_input_event = uhid_hid_input,
143         .parse = uhid_hid_parse,
144 };
145
146 static int uhid_dev_create(struct uhid_device *uhid,
147                            const struct uhid_event *ev)
148 {
149         struct hid_device *hid;
150         int ret;
151
152         if (uhid->running)
153                 return -EALREADY;
154
155         uhid->rd_size = ev->u.create.rd_size;
156         if (uhid->rd_size <= 0 || uhid->rd_size > HID_MAX_DESCRIPTOR_SIZE)
157                 return -EINVAL;
158
159         uhid->rd_data = kmalloc(uhid->rd_size, GFP_KERNEL);
160         if (!uhid->rd_data)
161                 return -ENOMEM;
162
163         if (copy_from_user(uhid->rd_data, ev->u.create.rd_data,
164                            uhid->rd_size)) {
165                 ret = -EFAULT;
166                 goto err_free;
167         }
168
169         hid = hid_allocate_device();
170         if (IS_ERR(hid)) {
171                 ret = PTR_ERR(hid);
172                 goto err_free;
173         }
174
175         strncpy(hid->name, ev->u.create.name, 127);
176         hid->name[127] = 0;
177         strncpy(hid->phys, ev->u.create.phys, 63);
178         hid->phys[63] = 0;
179         strncpy(hid->uniq, ev->u.create.uniq, 63);
180         hid->uniq[63] = 0;
181
182         hid->ll_driver = &uhid_hid_driver;
183         hid->hid_get_raw_report = uhid_hid_get_raw;
184         hid->hid_output_raw_report = uhid_hid_output_raw;
185         hid->bus = ev->u.create.bus;
186         hid->vendor = ev->u.create.vendor;
187         hid->product = ev->u.create.product;
188         hid->version = ev->u.create.version;
189         hid->country = ev->u.create.country;
190         hid->driver_data = uhid;
191         hid->dev.parent = uhid_misc.this_device;
192
193         uhid->hid = hid;
194         uhid->running = true;
195
196         ret = hid_add_device(hid);
197         if (ret) {
198                 hid_err(hid, "Cannot register HID device\n");
199                 goto err_hid;
200         }
201
202         return 0;
203
204 err_hid:
205         hid_destroy_device(hid);
206         uhid->hid = NULL;
207         uhid->running = false;
208 err_free:
209         kfree(uhid->rd_data);
210         return ret;
211 }
212
213 static int uhid_dev_destroy(struct uhid_device *uhid)
214 {
215         if (!uhid->running)
216                 return -EINVAL;
217
218         uhid->running = false;
219
220         hid_destroy_device(uhid->hid);
221         kfree(uhid->rd_data);
222
223         return 0;
224 }
225
226 static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
227 {
228         if (!uhid->running)
229                 return -EINVAL;
230
231         hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
232                          min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
233
234         return 0;
235 }
236
237 static int uhid_char_open(struct inode *inode, struct file *file)
238 {
239         struct uhid_device *uhid;
240
241         uhid = kzalloc(sizeof(*uhid), GFP_KERNEL);
242         if (!uhid)
243                 return -ENOMEM;
244
245         mutex_init(&uhid->devlock);
246         spin_lock_init(&uhid->qlock);
247         init_waitqueue_head(&uhid->waitq);
248         uhid->running = false;
249
250         file->private_data = uhid;
251         nonseekable_open(inode, file);
252
253         return 0;
254 }
255
256 static int uhid_char_release(struct inode *inode, struct file *file)
257 {
258         struct uhid_device *uhid = file->private_data;
259         unsigned int i;
260
261         uhid_dev_destroy(uhid);
262
263         for (i = 0; i < UHID_BUFSIZE; ++i)
264                 kfree(uhid->outq[i]);
265
266         kfree(uhid);
267
268         return 0;
269 }
270
271 static ssize_t uhid_char_read(struct file *file, char __user *buffer,
272                                 size_t count, loff_t *ppos)
273 {
274         struct uhid_device *uhid = file->private_data;
275         int ret;
276         unsigned long flags;
277         size_t len;
278
279         /* they need at least the "type" member of uhid_event */
280         if (count < sizeof(__u32))
281                 return -EINVAL;
282
283 try_again:
284         if (file->f_flags & O_NONBLOCK) {
285                 if (uhid->head == uhid->tail)
286                         return -EAGAIN;
287         } else {
288                 ret = wait_event_interruptible(uhid->waitq,
289                                                 uhid->head != uhid->tail);
290                 if (ret)
291                         return ret;
292         }
293
294         ret = mutex_lock_interruptible(&uhid->devlock);
295         if (ret)
296                 return ret;
297
298         if (uhid->head == uhid->tail) {
299                 mutex_unlock(&uhid->devlock);
300                 goto try_again;
301         } else {
302                 len = min(count, sizeof(**uhid->outq));
303                 if (copy_to_user(buffer, &uhid->outq[uhid->tail], len)) {
304                         ret = -EFAULT;
305                 } else {
306                         kfree(uhid->outq[uhid->tail]);
307                         uhid->outq[uhid->tail] = NULL;
308
309                         spin_lock_irqsave(&uhid->qlock, flags);
310                         uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE;
311                         spin_unlock_irqrestore(&uhid->qlock, flags);
312                 }
313         }
314
315         mutex_unlock(&uhid->devlock);
316         return ret ? ret : len;
317 }
318
319 static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
320                                 size_t count, loff_t *ppos)
321 {
322         struct uhid_device *uhid = file->private_data;
323         int ret;
324         size_t len;
325
326         /* we need at least the "type" member of uhid_event */
327         if (count < sizeof(__u32))
328                 return -EINVAL;
329
330         ret = mutex_lock_interruptible(&uhid->devlock);
331         if (ret)
332                 return ret;
333
334         memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
335         len = min(count, sizeof(uhid->input_buf));
336         if (copy_from_user(&uhid->input_buf, buffer, len)) {
337                 ret = -EFAULT;
338                 goto unlock;
339         }
340
341         switch (uhid->input_buf.type) {
342         case UHID_CREATE:
343                 ret = uhid_dev_create(uhid, &uhid->input_buf);
344                 break;
345         case UHID_DESTROY:
346                 ret = uhid_dev_destroy(uhid);
347                 break;
348         case UHID_INPUT:
349                 ret = uhid_dev_input(uhid, &uhid->input_buf);
350                 break;
351         default:
352                 ret = -EOPNOTSUPP;
353         }
354
355 unlock:
356         mutex_unlock(&uhid->devlock);
357
358         /* return "count" not "len" to not confuse the caller */
359         return ret ? ret : count;
360 }
361
362 static unsigned int uhid_char_poll(struct file *file, poll_table *wait)
363 {
364         struct uhid_device *uhid = file->private_data;
365
366         poll_wait(file, &uhid->waitq, wait);
367
368         if (uhid->head != uhid->tail)
369                 return POLLIN | POLLRDNORM;
370
371         return 0;
372 }
373
374 static const struct file_operations uhid_fops = {
375         .owner          = THIS_MODULE,
376         .open           = uhid_char_open,
377         .release        = uhid_char_release,
378         .read           = uhid_char_read,
379         .write          = uhid_char_write,
380         .poll           = uhid_char_poll,
381         .llseek         = no_llseek,
382 };
383
384 static struct miscdevice uhid_misc = {
385         .fops           = &uhid_fops,
386         .minor          = MISC_DYNAMIC_MINOR,
387         .name           = UHID_NAME,
388 };
389
390 static int __init uhid_init(void)
391 {
392         return misc_register(&uhid_misc);
393 }
394
395 static void __exit uhid_exit(void)
396 {
397         misc_deregister(&uhid_misc);
398 }
399
400 module_init(uhid_init);
401 module_exit(uhid_exit);
402 MODULE_LICENSE("GPL");
403 MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
404 MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");