Commit | Line | Data |
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1ccd7a2a DH |
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" | |
ace3d861 DH |
28 | #define UHID_BUFSIZE 32 |
29 | ||
30 | struct uhid_device { | |
d937ae5f | 31 | struct mutex devlock; |
d365c6cf DH |
32 | bool running; |
33 | ||
34 | __u8 *rd_data; | |
35 | uint rd_size; | |
36 | ||
ace3d861 | 37 | struct hid_device *hid; |
6664ef72 | 38 | struct uhid_event input_buf; |
ace3d861 DH |
39 | |
40 | wait_queue_head_t waitq; | |
41 | spinlock_t qlock; | |
42 | __u8 head; | |
43 | __u8 tail; | |
44 | struct uhid_event *outq[UHID_BUFSIZE]; | |
fcfcf0de DH |
45 | |
46 | struct mutex report_lock; | |
47 | wait_queue_head_t report_wait; | |
48 | atomic_t report_done; | |
49 | atomic_t report_id; | |
50 | struct uhid_event report_buf; | |
ace3d861 | 51 | }; |
1ccd7a2a DH |
52 | |
53 | static struct miscdevice uhid_misc; | |
54 | ||
ace3d861 DH |
55 | static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev) |
56 | { | |
57 | __u8 newhead; | |
58 | ||
59 | newhead = (uhid->head + 1) % UHID_BUFSIZE; | |
60 | ||
61 | if (newhead != uhid->tail) { | |
62 | uhid->outq[uhid->head] = ev; | |
63 | uhid->head = newhead; | |
64 | wake_up_interruptible(&uhid->waitq); | |
65 | } else { | |
66 | hid_warn(uhid->hid, "Output queue is full\n"); | |
67 | kfree(ev); | |
68 | } | |
69 | } | |
70 | ||
71 | static int uhid_queue_event(struct uhid_device *uhid, __u32 event) | |
72 | { | |
73 | unsigned long flags; | |
74 | struct uhid_event *ev; | |
75 | ||
76 | ev = kzalloc(sizeof(*ev), GFP_KERNEL); | |
77 | if (!ev) | |
78 | return -ENOMEM; | |
79 | ||
80 | ev->type = event; | |
81 | ||
82 | spin_lock_irqsave(&uhid->qlock, flags); | |
83 | uhid_queue(uhid, ev); | |
84 | spin_unlock_irqrestore(&uhid->qlock, flags); | |
85 | ||
86 | return 0; | |
87 | } | |
88 | ||
d365c6cf DH |
89 | static int uhid_hid_start(struct hid_device *hid) |
90 | { | |
ec4b7dea DH |
91 | struct uhid_device *uhid = hid->driver_data; |
92 | ||
93 | return uhid_queue_event(uhid, UHID_START); | |
d365c6cf DH |
94 | } |
95 | ||
96 | static void uhid_hid_stop(struct hid_device *hid) | |
97 | { | |
ec4b7dea DH |
98 | struct uhid_device *uhid = hid->driver_data; |
99 | ||
100 | hid->claimed = 0; | |
101 | uhid_queue_event(uhid, UHID_STOP); | |
d365c6cf DH |
102 | } |
103 | ||
104 | static int uhid_hid_open(struct hid_device *hid) | |
105 | { | |
e7191474 DH |
106 | struct uhid_device *uhid = hid->driver_data; |
107 | ||
108 | return uhid_queue_event(uhid, UHID_OPEN); | |
d365c6cf DH |
109 | } |
110 | ||
111 | static void uhid_hid_close(struct hid_device *hid) | |
112 | { | |
e7191474 DH |
113 | struct uhid_device *uhid = hid->driver_data; |
114 | ||
115 | uhid_queue_event(uhid, UHID_CLOSE); | |
d365c6cf DH |
116 | } |
117 | ||
118 | static int uhid_hid_input(struct input_dev *input, unsigned int type, | |
119 | unsigned int code, int value) | |
120 | { | |
f80e1360 DH |
121 | struct hid_device *hid = input_get_drvdata(input); |
122 | struct uhid_device *uhid = hid->driver_data; | |
123 | unsigned long flags; | |
124 | struct uhid_event *ev; | |
125 | ||
126 | ev = kzalloc(sizeof(*ev), GFP_ATOMIC); | |
127 | if (!ev) | |
128 | return -ENOMEM; | |
129 | ||
130 | ev->type = UHID_OUTPUT_EV; | |
131 | ev->u.output_ev.type = type; | |
132 | ev->u.output_ev.code = code; | |
133 | ev->u.output_ev.value = value; | |
134 | ||
135 | spin_lock_irqsave(&uhid->qlock, flags); | |
136 | uhid_queue(uhid, ev); | |
137 | spin_unlock_irqrestore(&uhid->qlock, flags); | |
138 | ||
d365c6cf DH |
139 | return 0; |
140 | } | |
141 | ||
142 | static int uhid_hid_parse(struct hid_device *hid) | |
143 | { | |
037c061b DH |
144 | struct uhid_device *uhid = hid->driver_data; |
145 | ||
146 | return hid_parse_report(hid, uhid->rd_data, uhid->rd_size); | |
d365c6cf DH |
147 | } |
148 | ||
149 | static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum, | |
150 | __u8 *buf, size_t count, unsigned char rtype) | |
151 | { | |
fcfcf0de DH |
152 | struct uhid_device *uhid = hid->driver_data; |
153 | __u8 report_type; | |
154 | struct uhid_event *ev; | |
155 | unsigned long flags; | |
156 | int ret; | |
1a8b294c | 157 | size_t uninitialized_var(len); |
fcfcf0de DH |
158 | struct uhid_feature_answer_req *req; |
159 | ||
160 | if (!uhid->running) | |
161 | return -EIO; | |
162 | ||
163 | switch (rtype) { | |
164 | case HID_FEATURE_REPORT: | |
165 | report_type = UHID_FEATURE_REPORT; | |
166 | break; | |
167 | case HID_OUTPUT_REPORT: | |
168 | report_type = UHID_OUTPUT_REPORT; | |
169 | break; | |
170 | case HID_INPUT_REPORT: | |
171 | report_type = UHID_INPUT_REPORT; | |
172 | break; | |
173 | default: | |
174 | return -EINVAL; | |
175 | } | |
176 | ||
177 | ret = mutex_lock_interruptible(&uhid->report_lock); | |
178 | if (ret) | |
179 | return ret; | |
180 | ||
181 | ev = kzalloc(sizeof(*ev), GFP_KERNEL); | |
182 | if (!ev) { | |
183 | ret = -ENOMEM; | |
184 | goto unlock; | |
185 | } | |
186 | ||
187 | spin_lock_irqsave(&uhid->qlock, flags); | |
188 | ev->type = UHID_FEATURE; | |
189 | ev->u.feature.id = atomic_inc_return(&uhid->report_id); | |
190 | ev->u.feature.rnum = rnum; | |
191 | ev->u.feature.rtype = report_type; | |
192 | ||
193 | atomic_set(&uhid->report_done, 0); | |
194 | uhid_queue(uhid, ev); | |
195 | spin_unlock_irqrestore(&uhid->qlock, flags); | |
196 | ||
197 | ret = wait_event_interruptible_timeout(uhid->report_wait, | |
198 | atomic_read(&uhid->report_done), 5 * HZ); | |
199 | ||
200 | /* | |
201 | * Make sure "uhid->running" is cleared on shutdown before | |
202 | * "uhid->report_done" is set. | |
203 | */ | |
204 | smp_rmb(); | |
205 | if (!ret || !uhid->running) { | |
206 | ret = -EIO; | |
207 | } else if (ret < 0) { | |
208 | ret = -ERESTARTSYS; | |
209 | } else { | |
210 | spin_lock_irqsave(&uhid->qlock, flags); | |
211 | req = &uhid->report_buf.u.feature_answer; | |
212 | ||
213 | if (req->err) { | |
214 | ret = -EIO; | |
215 | } else { | |
216 | ret = 0; | |
217 | len = min(count, | |
218 | min_t(size_t, req->size, UHID_DATA_MAX)); | |
219 | memcpy(buf, req->data, len); | |
220 | } | |
221 | ||
222 | spin_unlock_irqrestore(&uhid->qlock, flags); | |
223 | } | |
224 | ||
225 | atomic_set(&uhid->report_done, 1); | |
226 | ||
227 | unlock: | |
228 | mutex_unlock(&uhid->report_lock); | |
229 | return ret ? ret : len; | |
d365c6cf DH |
230 | } |
231 | ||
232 | static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count, | |
233 | unsigned char report_type) | |
234 | { | |
3b3baa82 DH |
235 | struct uhid_device *uhid = hid->driver_data; |
236 | __u8 rtype; | |
237 | unsigned long flags; | |
238 | struct uhid_event *ev; | |
239 | ||
240 | switch (report_type) { | |
241 | case HID_FEATURE_REPORT: | |
242 | rtype = UHID_FEATURE_REPORT; | |
243 | break; | |
244 | case HID_OUTPUT_REPORT: | |
245 | rtype = UHID_OUTPUT_REPORT; | |
246 | break; | |
247 | default: | |
248 | return -EINVAL; | |
249 | } | |
250 | ||
251 | if (count < 1 || count > UHID_DATA_MAX) | |
252 | return -EINVAL; | |
253 | ||
254 | ev = kzalloc(sizeof(*ev), GFP_KERNEL); | |
255 | if (!ev) | |
256 | return -ENOMEM; | |
257 | ||
258 | ev->type = UHID_OUTPUT; | |
259 | ev->u.output.size = count; | |
260 | ev->u.output.rtype = rtype; | |
261 | memcpy(ev->u.output.data, buf, count); | |
262 | ||
263 | spin_lock_irqsave(&uhid->qlock, flags); | |
264 | uhid_queue(uhid, ev); | |
265 | spin_unlock_irqrestore(&uhid->qlock, flags); | |
266 | ||
267 | return count; | |
d365c6cf DH |
268 | } |
269 | ||
270 | static struct hid_ll_driver uhid_hid_driver = { | |
271 | .start = uhid_hid_start, | |
272 | .stop = uhid_hid_stop, | |
273 | .open = uhid_hid_open, | |
274 | .close = uhid_hid_close, | |
275 | .hidinput_input_event = uhid_hid_input, | |
276 | .parse = uhid_hid_parse, | |
277 | }; | |
278 | ||
279 | static int uhid_dev_create(struct uhid_device *uhid, | |
280 | const struct uhid_event *ev) | |
281 | { | |
282 | struct hid_device *hid; | |
283 | int ret; | |
284 | ||
285 | if (uhid->running) | |
286 | return -EALREADY; | |
287 | ||
288 | uhid->rd_size = ev->u.create.rd_size; | |
289 | if (uhid->rd_size <= 0 || uhid->rd_size > HID_MAX_DESCRIPTOR_SIZE) | |
290 | return -EINVAL; | |
291 | ||
292 | uhid->rd_data = kmalloc(uhid->rd_size, GFP_KERNEL); | |
293 | if (!uhid->rd_data) | |
294 | return -ENOMEM; | |
295 | ||
296 | if (copy_from_user(uhid->rd_data, ev->u.create.rd_data, | |
297 | uhid->rd_size)) { | |
298 | ret = -EFAULT; | |
299 | goto err_free; | |
300 | } | |
301 | ||
302 | hid = hid_allocate_device(); | |
303 | if (IS_ERR(hid)) { | |
304 | ret = PTR_ERR(hid); | |
305 | goto err_free; | |
306 | } | |
307 | ||
308 | strncpy(hid->name, ev->u.create.name, 127); | |
309 | hid->name[127] = 0; | |
310 | strncpy(hid->phys, ev->u.create.phys, 63); | |
311 | hid->phys[63] = 0; | |
312 | strncpy(hid->uniq, ev->u.create.uniq, 63); | |
313 | hid->uniq[63] = 0; | |
314 | ||
315 | hid->ll_driver = &uhid_hid_driver; | |
316 | hid->hid_get_raw_report = uhid_hid_get_raw; | |
317 | hid->hid_output_raw_report = uhid_hid_output_raw; | |
318 | hid->bus = ev->u.create.bus; | |
319 | hid->vendor = ev->u.create.vendor; | |
320 | hid->product = ev->u.create.product; | |
321 | hid->version = ev->u.create.version; | |
322 | hid->country = ev->u.create.country; | |
323 | hid->driver_data = uhid; | |
324 | hid->dev.parent = uhid_misc.this_device; | |
325 | ||
326 | uhid->hid = hid; | |
327 | uhid->running = true; | |
328 | ||
329 | ret = hid_add_device(hid); | |
330 | if (ret) { | |
331 | hid_err(hid, "Cannot register HID device\n"); | |
332 | goto err_hid; | |
333 | } | |
334 | ||
335 | return 0; | |
336 | ||
337 | err_hid: | |
338 | hid_destroy_device(hid); | |
339 | uhid->hid = NULL; | |
340 | uhid->running = false; | |
341 | err_free: | |
342 | kfree(uhid->rd_data); | |
343 | return ret; | |
344 | } | |
345 | ||
346 | static int uhid_dev_destroy(struct uhid_device *uhid) | |
347 | { | |
348 | if (!uhid->running) | |
349 | return -EINVAL; | |
350 | ||
fcfcf0de | 351 | /* clear "running" before setting "report_done" */ |
d365c6cf | 352 | uhid->running = false; |
fcfcf0de DH |
353 | smp_wmb(); |
354 | atomic_set(&uhid->report_done, 1); | |
355 | wake_up_interruptible(&uhid->report_wait); | |
d365c6cf DH |
356 | |
357 | hid_destroy_device(uhid->hid); | |
358 | kfree(uhid->rd_data); | |
359 | ||
360 | return 0; | |
361 | } | |
362 | ||
5e87a36a DH |
363 | static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev) |
364 | { | |
365 | if (!uhid->running) | |
366 | return -EINVAL; | |
367 | ||
368 | hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data, | |
369 | min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0); | |
370 | ||
371 | return 0; | |
372 | } | |
373 | ||
fcfcf0de DH |
374 | static int uhid_dev_feature_answer(struct uhid_device *uhid, |
375 | struct uhid_event *ev) | |
376 | { | |
377 | unsigned long flags; | |
378 | ||
379 | if (!uhid->running) | |
380 | return -EINVAL; | |
381 | ||
382 | spin_lock_irqsave(&uhid->qlock, flags); | |
383 | ||
384 | /* id for old report; drop it silently */ | |
385 | if (atomic_read(&uhid->report_id) != ev->u.feature_answer.id) | |
386 | goto unlock; | |
387 | if (atomic_read(&uhid->report_done)) | |
388 | goto unlock; | |
389 | ||
390 | memcpy(&uhid->report_buf, ev, sizeof(*ev)); | |
391 | atomic_set(&uhid->report_done, 1); | |
392 | wake_up_interruptible(&uhid->report_wait); | |
393 | ||
394 | unlock: | |
395 | spin_unlock_irqrestore(&uhid->qlock, flags); | |
396 | return 0; | |
397 | } | |
398 | ||
1ccd7a2a DH |
399 | static int uhid_char_open(struct inode *inode, struct file *file) |
400 | { | |
ace3d861 DH |
401 | struct uhid_device *uhid; |
402 | ||
403 | uhid = kzalloc(sizeof(*uhid), GFP_KERNEL); | |
404 | if (!uhid) | |
405 | return -ENOMEM; | |
406 | ||
d937ae5f | 407 | mutex_init(&uhid->devlock); |
fcfcf0de | 408 | mutex_init(&uhid->report_lock); |
ace3d861 DH |
409 | spin_lock_init(&uhid->qlock); |
410 | init_waitqueue_head(&uhid->waitq); | |
fcfcf0de | 411 | init_waitqueue_head(&uhid->report_wait); |
d365c6cf | 412 | uhid->running = false; |
fcfcf0de | 413 | atomic_set(&uhid->report_done, 1); |
ace3d861 DH |
414 | |
415 | file->private_data = uhid; | |
416 | nonseekable_open(inode, file); | |
417 | ||
1ccd7a2a DH |
418 | return 0; |
419 | } | |
420 | ||
421 | static int uhid_char_release(struct inode *inode, struct file *file) | |
422 | { | |
ace3d861 DH |
423 | struct uhid_device *uhid = file->private_data; |
424 | unsigned int i; | |
425 | ||
d365c6cf DH |
426 | uhid_dev_destroy(uhid); |
427 | ||
ace3d861 DH |
428 | for (i = 0; i < UHID_BUFSIZE; ++i) |
429 | kfree(uhid->outq[i]); | |
430 | ||
431 | kfree(uhid); | |
432 | ||
1ccd7a2a DH |
433 | return 0; |
434 | } | |
435 | ||
436 | static ssize_t uhid_char_read(struct file *file, char __user *buffer, | |
437 | size_t count, loff_t *ppos) | |
438 | { | |
d937ae5f DH |
439 | struct uhid_device *uhid = file->private_data; |
440 | int ret; | |
441 | unsigned long flags; | |
442 | size_t len; | |
443 | ||
444 | /* they need at least the "type" member of uhid_event */ | |
445 | if (count < sizeof(__u32)) | |
446 | return -EINVAL; | |
447 | ||
448 | try_again: | |
449 | if (file->f_flags & O_NONBLOCK) { | |
450 | if (uhid->head == uhid->tail) | |
451 | return -EAGAIN; | |
452 | } else { | |
453 | ret = wait_event_interruptible(uhid->waitq, | |
454 | uhid->head != uhid->tail); | |
455 | if (ret) | |
456 | return ret; | |
457 | } | |
458 | ||
459 | ret = mutex_lock_interruptible(&uhid->devlock); | |
460 | if (ret) | |
461 | return ret; | |
462 | ||
463 | if (uhid->head == uhid->tail) { | |
464 | mutex_unlock(&uhid->devlock); | |
465 | goto try_again; | |
466 | } else { | |
467 | len = min(count, sizeof(**uhid->outq)); | |
adefb69b | 468 | if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) { |
d937ae5f DH |
469 | ret = -EFAULT; |
470 | } else { | |
471 | kfree(uhid->outq[uhid->tail]); | |
472 | uhid->outq[uhid->tail] = NULL; | |
473 | ||
474 | spin_lock_irqsave(&uhid->qlock, flags); | |
475 | uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE; | |
476 | spin_unlock_irqrestore(&uhid->qlock, flags); | |
477 | } | |
478 | } | |
479 | ||
480 | mutex_unlock(&uhid->devlock); | |
481 | return ret ? ret : len; | |
1ccd7a2a DH |
482 | } |
483 | ||
484 | static ssize_t uhid_char_write(struct file *file, const char __user *buffer, | |
485 | size_t count, loff_t *ppos) | |
486 | { | |
6664ef72 DH |
487 | struct uhid_device *uhid = file->private_data; |
488 | int ret; | |
489 | size_t len; | |
490 | ||
491 | /* we need at least the "type" member of uhid_event */ | |
492 | if (count < sizeof(__u32)) | |
493 | return -EINVAL; | |
494 | ||
495 | ret = mutex_lock_interruptible(&uhid->devlock); | |
496 | if (ret) | |
497 | return ret; | |
498 | ||
499 | memset(&uhid->input_buf, 0, sizeof(uhid->input_buf)); | |
500 | len = min(count, sizeof(uhid->input_buf)); | |
501 | if (copy_from_user(&uhid->input_buf, buffer, len)) { | |
502 | ret = -EFAULT; | |
503 | goto unlock; | |
504 | } | |
505 | ||
506 | switch (uhid->input_buf.type) { | |
d365c6cf DH |
507 | case UHID_CREATE: |
508 | ret = uhid_dev_create(uhid, &uhid->input_buf); | |
509 | break; | |
510 | case UHID_DESTROY: | |
511 | ret = uhid_dev_destroy(uhid); | |
512 | break; | |
5e87a36a DH |
513 | case UHID_INPUT: |
514 | ret = uhid_dev_input(uhid, &uhid->input_buf); | |
515 | break; | |
fcfcf0de DH |
516 | case UHID_FEATURE_ANSWER: |
517 | ret = uhid_dev_feature_answer(uhid, &uhid->input_buf); | |
518 | break; | |
6664ef72 DH |
519 | default: |
520 | ret = -EOPNOTSUPP; | |
521 | } | |
522 | ||
523 | unlock: | |
524 | mutex_unlock(&uhid->devlock); | |
525 | ||
526 | /* return "count" not "len" to not confuse the caller */ | |
527 | return ret ? ret : count; | |
1ccd7a2a DH |
528 | } |
529 | ||
530 | static unsigned int uhid_char_poll(struct file *file, poll_table *wait) | |
531 | { | |
1f9dec1e DH |
532 | struct uhid_device *uhid = file->private_data; |
533 | ||
534 | poll_wait(file, &uhid->waitq, wait); | |
535 | ||
536 | if (uhid->head != uhid->tail) | |
537 | return POLLIN | POLLRDNORM; | |
538 | ||
1ccd7a2a DH |
539 | return 0; |
540 | } | |
541 | ||
542 | static const struct file_operations uhid_fops = { | |
543 | .owner = THIS_MODULE, | |
544 | .open = uhid_char_open, | |
545 | .release = uhid_char_release, | |
546 | .read = uhid_char_read, | |
547 | .write = uhid_char_write, | |
548 | .poll = uhid_char_poll, | |
549 | .llseek = no_llseek, | |
550 | }; | |
551 | ||
552 | static struct miscdevice uhid_misc = { | |
553 | .fops = &uhid_fops, | |
554 | .minor = MISC_DYNAMIC_MINOR, | |
555 | .name = UHID_NAME, | |
556 | }; | |
557 | ||
558 | static int __init uhid_init(void) | |
559 | { | |
560 | return misc_register(&uhid_misc); | |
561 | } | |
562 | ||
563 | static void __exit uhid_exit(void) | |
564 | { | |
565 | misc_deregister(&uhid_misc); | |
566 | } | |
567 | ||
568 | module_init(uhid_init); | |
569 | module_exit(uhid_exit); | |
570 | MODULE_LICENSE("GPL"); | |
571 | MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>"); | |
572 | MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem"); |