HID: uhid: forward raw output reports 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         struct hid_device *hid = input_get_drvdata(input);
116         struct uhid_device *uhid = hid->driver_data;
117         unsigned long flags;
118         struct uhid_event *ev;
119
120         ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
121         if (!ev)
122                 return -ENOMEM;
123
124         ev->type = UHID_OUTPUT_EV;
125         ev->u.output_ev.type = type;
126         ev->u.output_ev.code = code;
127         ev->u.output_ev.value = value;
128
129         spin_lock_irqsave(&uhid->qlock, flags);
130         uhid_queue(uhid, ev);
131         spin_unlock_irqrestore(&uhid->qlock, flags);
132
133         return 0;
134 }
135
136 static int uhid_hid_parse(struct hid_device *hid)
137 {
138         struct uhid_device *uhid = hid->driver_data;
139
140         return hid_parse_report(hid, uhid->rd_data, uhid->rd_size);
141 }
142
143 static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum,
144                             __u8 *buf, size_t count, unsigned char rtype)
145 {
146         return 0;
147 }
148
149 static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
150                                unsigned char report_type)
151 {
152         struct uhid_device *uhid = hid->driver_data;
153         __u8 rtype;
154         unsigned long flags;
155         struct uhid_event *ev;
156
157         switch (report_type) {
158         case HID_FEATURE_REPORT:
159                 rtype = UHID_FEATURE_REPORT;
160                 break;
161         case HID_OUTPUT_REPORT:
162                 rtype = UHID_OUTPUT_REPORT;
163                 break;
164         default:
165                 return -EINVAL;
166         }
167
168         if (count < 1 || count > UHID_DATA_MAX)
169                 return -EINVAL;
170
171         ev = kzalloc(sizeof(*ev), GFP_KERNEL);
172         if (!ev)
173                 return -ENOMEM;
174
175         ev->type = UHID_OUTPUT;
176         ev->u.output.size = count;
177         ev->u.output.rtype = rtype;
178         memcpy(ev->u.output.data, buf, count);
179
180         spin_lock_irqsave(&uhid->qlock, flags);
181         uhid_queue(uhid, ev);
182         spin_unlock_irqrestore(&uhid->qlock, flags);
183
184         return count;
185 }
186
187 static struct hid_ll_driver uhid_hid_driver = {
188         .start = uhid_hid_start,
189         .stop = uhid_hid_stop,
190         .open = uhid_hid_open,
191         .close = uhid_hid_close,
192         .hidinput_input_event = uhid_hid_input,
193         .parse = uhid_hid_parse,
194 };
195
196 static int uhid_dev_create(struct uhid_device *uhid,
197                            const struct uhid_event *ev)
198 {
199         struct hid_device *hid;
200         int ret;
201
202         if (uhid->running)
203                 return -EALREADY;
204
205         uhid->rd_size = ev->u.create.rd_size;
206         if (uhid->rd_size <= 0 || uhid->rd_size > HID_MAX_DESCRIPTOR_SIZE)
207                 return -EINVAL;
208
209         uhid->rd_data = kmalloc(uhid->rd_size, GFP_KERNEL);
210         if (!uhid->rd_data)
211                 return -ENOMEM;
212
213         if (copy_from_user(uhid->rd_data, ev->u.create.rd_data,
214                            uhid->rd_size)) {
215                 ret = -EFAULT;
216                 goto err_free;
217         }
218
219         hid = hid_allocate_device();
220         if (IS_ERR(hid)) {
221                 ret = PTR_ERR(hid);
222                 goto err_free;
223         }
224
225         strncpy(hid->name, ev->u.create.name, 127);
226         hid->name[127] = 0;
227         strncpy(hid->phys, ev->u.create.phys, 63);
228         hid->phys[63] = 0;
229         strncpy(hid->uniq, ev->u.create.uniq, 63);
230         hid->uniq[63] = 0;
231
232         hid->ll_driver = &uhid_hid_driver;
233         hid->hid_get_raw_report = uhid_hid_get_raw;
234         hid->hid_output_raw_report = uhid_hid_output_raw;
235         hid->bus = ev->u.create.bus;
236         hid->vendor = ev->u.create.vendor;
237         hid->product = ev->u.create.product;
238         hid->version = ev->u.create.version;
239         hid->country = ev->u.create.country;
240         hid->driver_data = uhid;
241         hid->dev.parent = uhid_misc.this_device;
242
243         uhid->hid = hid;
244         uhid->running = true;
245
246         ret = hid_add_device(hid);
247         if (ret) {
248                 hid_err(hid, "Cannot register HID device\n");
249                 goto err_hid;
250         }
251
252         return 0;
253
254 err_hid:
255         hid_destroy_device(hid);
256         uhid->hid = NULL;
257         uhid->running = false;
258 err_free:
259         kfree(uhid->rd_data);
260         return ret;
261 }
262
263 static int uhid_dev_destroy(struct uhid_device *uhid)
264 {
265         if (!uhid->running)
266                 return -EINVAL;
267
268         uhid->running = false;
269
270         hid_destroy_device(uhid->hid);
271         kfree(uhid->rd_data);
272
273         return 0;
274 }
275
276 static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
277 {
278         if (!uhid->running)
279                 return -EINVAL;
280
281         hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
282                          min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
283
284         return 0;
285 }
286
287 static int uhid_char_open(struct inode *inode, struct file *file)
288 {
289         struct uhid_device *uhid;
290
291         uhid = kzalloc(sizeof(*uhid), GFP_KERNEL);
292         if (!uhid)
293                 return -ENOMEM;
294
295         mutex_init(&uhid->devlock);
296         spin_lock_init(&uhid->qlock);
297         init_waitqueue_head(&uhid->waitq);
298         uhid->running = false;
299
300         file->private_data = uhid;
301         nonseekable_open(inode, file);
302
303         return 0;
304 }
305
306 static int uhid_char_release(struct inode *inode, struct file *file)
307 {
308         struct uhid_device *uhid = file->private_data;
309         unsigned int i;
310
311         uhid_dev_destroy(uhid);
312
313         for (i = 0; i < UHID_BUFSIZE; ++i)
314                 kfree(uhid->outq[i]);
315
316         kfree(uhid);
317
318         return 0;
319 }
320
321 static ssize_t uhid_char_read(struct file *file, char __user *buffer,
322                                 size_t count, loff_t *ppos)
323 {
324         struct uhid_device *uhid = file->private_data;
325         int ret;
326         unsigned long flags;
327         size_t len;
328
329         /* they need at least the "type" member of uhid_event */
330         if (count < sizeof(__u32))
331                 return -EINVAL;
332
333 try_again:
334         if (file->f_flags & O_NONBLOCK) {
335                 if (uhid->head == uhid->tail)
336                         return -EAGAIN;
337         } else {
338                 ret = wait_event_interruptible(uhid->waitq,
339                                                 uhid->head != uhid->tail);
340                 if (ret)
341                         return ret;
342         }
343
344         ret = mutex_lock_interruptible(&uhid->devlock);
345         if (ret)
346                 return ret;
347
348         if (uhid->head == uhid->tail) {
349                 mutex_unlock(&uhid->devlock);
350                 goto try_again;
351         } else {
352                 len = min(count, sizeof(**uhid->outq));
353                 if (copy_to_user(buffer, &uhid->outq[uhid->tail], len)) {
354                         ret = -EFAULT;
355                 } else {
356                         kfree(uhid->outq[uhid->tail]);
357                         uhid->outq[uhid->tail] = NULL;
358
359                         spin_lock_irqsave(&uhid->qlock, flags);
360                         uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE;
361                         spin_unlock_irqrestore(&uhid->qlock, flags);
362                 }
363         }
364
365         mutex_unlock(&uhid->devlock);
366         return ret ? ret : len;
367 }
368
369 static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
370                                 size_t count, loff_t *ppos)
371 {
372         struct uhid_device *uhid = file->private_data;
373         int ret;
374         size_t len;
375
376         /* we need at least the "type" member of uhid_event */
377         if (count < sizeof(__u32))
378                 return -EINVAL;
379
380         ret = mutex_lock_interruptible(&uhid->devlock);
381         if (ret)
382                 return ret;
383
384         memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
385         len = min(count, sizeof(uhid->input_buf));
386         if (copy_from_user(&uhid->input_buf, buffer, len)) {
387                 ret = -EFAULT;
388                 goto unlock;
389         }
390
391         switch (uhid->input_buf.type) {
392         case UHID_CREATE:
393                 ret = uhid_dev_create(uhid, &uhid->input_buf);
394                 break;
395         case UHID_DESTROY:
396                 ret = uhid_dev_destroy(uhid);
397                 break;
398         case UHID_INPUT:
399                 ret = uhid_dev_input(uhid, &uhid->input_buf);
400                 break;
401         default:
402                 ret = -EOPNOTSUPP;
403         }
404
405 unlock:
406         mutex_unlock(&uhid->devlock);
407
408         /* return "count" not "len" to not confuse the caller */
409         return ret ? ret : count;
410 }
411
412 static unsigned int uhid_char_poll(struct file *file, poll_table *wait)
413 {
414         struct uhid_device *uhid = file->private_data;
415
416         poll_wait(file, &uhid->waitq, wait);
417
418         if (uhid->head != uhid->tail)
419                 return POLLIN | POLLRDNORM;
420
421         return 0;
422 }
423
424 static const struct file_operations uhid_fops = {
425         .owner          = THIS_MODULE,
426         .open           = uhid_char_open,
427         .release        = uhid_char_release,
428         .read           = uhid_char_read,
429         .write          = uhid_char_write,
430         .poll           = uhid_char_poll,
431         .llseek         = no_llseek,
432 };
433
434 static struct miscdevice uhid_misc = {
435         .fops           = &uhid_fops,
436         .minor          = MISC_DYNAMIC_MINOR,
437         .name           = UHID_NAME,
438 };
439
440 static int __init uhid_init(void)
441 {
442         return misc_register(&uhid_misc);
443 }
444
445 static void __exit uhid_exit(void)
446 {
447         misc_deregister(&uhid_misc);
448 }
449
450 module_init(uhid_init);
451 module_exit(uhid_exit);
452 MODULE_LICENSE("GPL");
453 MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
454 MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");