blob: cedc6da93c19c5c77136127feb207a424899a321 [file] [log] [blame]
David Herrmann1ccd7a22012-06-10 15:16:13 +02001/*
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>
Dmitry Torokhovbefde022013-02-18 11:26:11 +010014#include <linux/compat.h>
David Herrmann1ccd7a22012-06-10 15:16:13 +020015#include <linux/device.h>
16#include <linux/fs.h>
17#include <linux/hid.h>
18#include <linux/input.h>
19#include <linux/miscdevice.h>
20#include <linux/module.h>
21#include <linux/mutex.h>
22#include <linux/poll.h>
23#include <linux/sched.h>
24#include <linux/spinlock.h>
25#include <linux/uhid.h>
26#include <linux/wait.h>
27
28#define UHID_NAME "uhid"
David Herrmannace3d862012-06-10 15:16:14 +020029#define UHID_BUFSIZE 32
30
31struct uhid_device {
David Herrmannd937ae52012-06-10 15:16:16 +020032 struct mutex devlock;
David Herrmannd365c6c2012-06-10 15:16:18 +020033 bool running;
34
35 __u8 *rd_data;
36 uint rd_size;
37
David Herrmannace3d862012-06-10 15:16:14 +020038 struct hid_device *hid;
David Herrmann6664ef72012-06-10 15:16:17 +020039 struct uhid_event input_buf;
David Herrmannace3d862012-06-10 15:16:14 +020040
41 wait_queue_head_t waitq;
42 spinlock_t qlock;
43 __u8 head;
44 __u8 tail;
45 struct uhid_event *outq[UHID_BUFSIZE];
David Herrmannfcfcf0d2012-06-10 15:16:25 +020046
47 struct mutex report_lock;
48 wait_queue_head_t report_wait;
49 atomic_t report_done;
50 atomic_t report_id;
51 struct uhid_event report_buf;
David Herrmannace3d862012-06-10 15:16:14 +020052};
David Herrmann1ccd7a22012-06-10 15:16:13 +020053
54static struct miscdevice uhid_misc;
55
David Herrmannace3d862012-06-10 15:16:14 +020056static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev)
57{
58 __u8 newhead;
59
60 newhead = (uhid->head + 1) % UHID_BUFSIZE;
61
62 if (newhead != uhid->tail) {
63 uhid->outq[uhid->head] = ev;
64 uhid->head = newhead;
65 wake_up_interruptible(&uhid->waitq);
66 } else {
67 hid_warn(uhid->hid, "Output queue is full\n");
68 kfree(ev);
69 }
70}
71
72static int uhid_queue_event(struct uhid_device *uhid, __u32 event)
73{
74 unsigned long flags;
75 struct uhid_event *ev;
76
77 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
78 if (!ev)
79 return -ENOMEM;
80
81 ev->type = event;
82
83 spin_lock_irqsave(&uhid->qlock, flags);
84 uhid_queue(uhid, ev);
85 spin_unlock_irqrestore(&uhid->qlock, flags);
86
87 return 0;
88}
89
David Herrmannd365c6c2012-06-10 15:16:18 +020090static int uhid_hid_start(struct hid_device *hid)
91{
David Herrmannec4b7de2012-06-10 15:16:21 +020092 struct uhid_device *uhid = hid->driver_data;
93
94 return uhid_queue_event(uhid, UHID_START);
David Herrmannd365c6c2012-06-10 15:16:18 +020095}
96
97static void uhid_hid_stop(struct hid_device *hid)
98{
David Herrmannec4b7de2012-06-10 15:16:21 +020099 struct uhid_device *uhid = hid->driver_data;
100
101 hid->claimed = 0;
102 uhid_queue_event(uhid, UHID_STOP);
David Herrmannd365c6c2012-06-10 15:16:18 +0200103}
104
105static int uhid_hid_open(struct hid_device *hid)
106{
David Herrmanne7191472012-06-10 15:16:22 +0200107 struct uhid_device *uhid = hid->driver_data;
108
109 return uhid_queue_event(uhid, UHID_OPEN);
David Herrmannd365c6c2012-06-10 15:16:18 +0200110}
111
112static void uhid_hid_close(struct hid_device *hid)
113{
David Herrmanne7191472012-06-10 15:16:22 +0200114 struct uhid_device *uhid = hid->driver_data;
115
116 uhid_queue_event(uhid, UHID_CLOSE);
David Herrmannd365c6c2012-06-10 15:16:18 +0200117}
118
David Herrmannd365c6c2012-06-10 15:16:18 +0200119static int uhid_hid_parse(struct hid_device *hid)
120{
David Herrmann037c0612012-06-10 15:16:20 +0200121 struct uhid_device *uhid = hid->driver_data;
122
123 return hid_parse_report(hid, uhid->rd_data, uhid->rd_size);
David Herrmannd365c6c2012-06-10 15:16:18 +0200124}
125
126static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum,
127 __u8 *buf, size_t count, unsigned char rtype)
128{
David Herrmannfcfcf0d2012-06-10 15:16:25 +0200129 struct uhid_device *uhid = hid->driver_data;
130 __u8 report_type;
131 struct uhid_event *ev;
132 unsigned long flags;
133 int ret;
Jiri Kosina1a8b2942012-06-18 17:08:08 +0200134 size_t uninitialized_var(len);
David Herrmannfcfcf0d2012-06-10 15:16:25 +0200135 struct uhid_feature_answer_req *req;
136
137 if (!uhid->running)
138 return -EIO;
139
140 switch (rtype) {
141 case HID_FEATURE_REPORT:
142 report_type = UHID_FEATURE_REPORT;
143 break;
144 case HID_OUTPUT_REPORT:
145 report_type = UHID_OUTPUT_REPORT;
146 break;
147 case HID_INPUT_REPORT:
148 report_type = UHID_INPUT_REPORT;
149 break;
150 default:
151 return -EINVAL;
152 }
153
154 ret = mutex_lock_interruptible(&uhid->report_lock);
155 if (ret)
156 return ret;
157
158 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
159 if (!ev) {
160 ret = -ENOMEM;
161 goto unlock;
162 }
163
164 spin_lock_irqsave(&uhid->qlock, flags);
165 ev->type = UHID_FEATURE;
166 ev->u.feature.id = atomic_inc_return(&uhid->report_id);
167 ev->u.feature.rnum = rnum;
168 ev->u.feature.rtype = report_type;
169
170 atomic_set(&uhid->report_done, 0);
171 uhid_queue(uhid, ev);
172 spin_unlock_irqrestore(&uhid->qlock, flags);
173
174 ret = wait_event_interruptible_timeout(uhid->report_wait,
175 atomic_read(&uhid->report_done), 5 * HZ);
176
177 /*
178 * Make sure "uhid->running" is cleared on shutdown before
179 * "uhid->report_done" is set.
180 */
181 smp_rmb();
182 if (!ret || !uhid->running) {
183 ret = -EIO;
184 } else if (ret < 0) {
185 ret = -ERESTARTSYS;
186 } else {
187 spin_lock_irqsave(&uhid->qlock, flags);
188 req = &uhid->report_buf.u.feature_answer;
189
190 if (req->err) {
191 ret = -EIO;
192 } else {
193 ret = 0;
194 len = min(count,
195 min_t(size_t, req->size, UHID_DATA_MAX));
196 memcpy(buf, req->data, len);
197 }
198
199 spin_unlock_irqrestore(&uhid->qlock, flags);
200 }
201
202 atomic_set(&uhid->report_done, 1);
203
204unlock:
205 mutex_unlock(&uhid->report_lock);
206 return ret ? ret : len;
David Herrmannd365c6c2012-06-10 15:16:18 +0200207}
208
209static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
210 unsigned char report_type)
211{
David Herrmann3b3baa82012-06-10 15:16:24 +0200212 struct uhid_device *uhid = hid->driver_data;
213 __u8 rtype;
214 unsigned long flags;
215 struct uhid_event *ev;
216
217 switch (report_type) {
218 case HID_FEATURE_REPORT:
219 rtype = UHID_FEATURE_REPORT;
220 break;
221 case HID_OUTPUT_REPORT:
222 rtype = UHID_OUTPUT_REPORT;
223 break;
224 default:
225 return -EINVAL;
226 }
227
228 if (count < 1 || count > UHID_DATA_MAX)
229 return -EINVAL;
230
231 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
232 if (!ev)
233 return -ENOMEM;
234
235 ev->type = UHID_OUTPUT;
236 ev->u.output.size = count;
237 ev->u.output.rtype = rtype;
238 memcpy(ev->u.output.data, buf, count);
239
240 spin_lock_irqsave(&uhid->qlock, flags);
241 uhid_queue(uhid, ev);
242 spin_unlock_irqrestore(&uhid->qlock, flags);
243
244 return count;
David Herrmannd365c6c2012-06-10 15:16:18 +0200245}
246
247static struct hid_ll_driver uhid_hid_driver = {
248 .start = uhid_hid_start,
249 .stop = uhid_hid_stop,
250 .open = uhid_hid_open,
251 .close = uhid_hid_close,
David Herrmannd365c6c2012-06-10 15:16:18 +0200252 .parse = uhid_hid_parse,
253};
254
Dmitry Torokhovbefde022013-02-18 11:26:11 +0100255#ifdef CONFIG_COMPAT
256
257/* Apparently we haven't stepped on these rakes enough times yet. */
258struct uhid_create_req_compat {
259 __u8 name[128];
260 __u8 phys[64];
261 __u8 uniq[64];
262
263 compat_uptr_t rd_data;
264 __u16 rd_size;
265
266 __u16 bus;
267 __u32 vendor;
268 __u32 product;
269 __u32 version;
270 __u32 country;
271} __attribute__((__packed__));
272
273static int uhid_event_from_user(const char __user *buffer, size_t len,
274 struct uhid_event *event)
275{
276 if (is_compat_task()) {
277 u32 type;
278
279 if (get_user(type, buffer))
280 return -EFAULT;
281
282 if (type == UHID_CREATE) {
283 /*
284 * This is our messed up request with compat pointer.
285 * It is largish (more than 256 bytes) so we better
286 * allocate it from the heap.
287 */
288 struct uhid_create_req_compat *compat;
289
David Herrmann80897aa2013-11-26 13:58:18 +0100290 compat = kzalloc(sizeof(*compat), GFP_KERNEL);
Dmitry Torokhovbefde022013-02-18 11:26:11 +0100291 if (!compat)
292 return -ENOMEM;
293
294 buffer += sizeof(type);
295 len -= sizeof(type);
296 if (copy_from_user(compat, buffer,
297 min(len, sizeof(*compat)))) {
298 kfree(compat);
299 return -EFAULT;
300 }
301
302 /* Shuffle the data over to proper structure */
303 event->type = type;
304
305 memcpy(event->u.create.name, compat->name,
306 sizeof(compat->name));
307 memcpy(event->u.create.phys, compat->phys,
308 sizeof(compat->phys));
309 memcpy(event->u.create.uniq, compat->uniq,
310 sizeof(compat->uniq));
311
312 event->u.create.rd_data = compat_ptr(compat->rd_data);
313 event->u.create.rd_size = compat->rd_size;
314
315 event->u.create.bus = compat->bus;
316 event->u.create.vendor = compat->vendor;
317 event->u.create.product = compat->product;
318 event->u.create.version = compat->version;
319 event->u.create.country = compat->country;
320
321 kfree(compat);
322 return 0;
323 }
324 /* All others can be copied directly */
325 }
326
327 if (copy_from_user(event, buffer, min(len, sizeof(*event))))
328 return -EFAULT;
329
330 return 0;
331}
332#else
333static int uhid_event_from_user(const char __user *buffer, size_t len,
334 struct uhid_event *event)
335{
336 if (copy_from_user(event, buffer, min(len, sizeof(*event))))
337 return -EFAULT;
338
339 return 0;
340}
341#endif
342
David Herrmannd365c6c2012-06-10 15:16:18 +0200343static int uhid_dev_create(struct uhid_device *uhid,
344 const struct uhid_event *ev)
345{
346 struct hid_device *hid;
347 int ret;
348
349 if (uhid->running)
350 return -EALREADY;
351
352 uhid->rd_size = ev->u.create.rd_size;
353 if (uhid->rd_size <= 0 || uhid->rd_size > HID_MAX_DESCRIPTOR_SIZE)
354 return -EINVAL;
355
356 uhid->rd_data = kmalloc(uhid->rd_size, GFP_KERNEL);
357 if (!uhid->rd_data)
358 return -ENOMEM;
359
360 if (copy_from_user(uhid->rd_data, ev->u.create.rd_data,
361 uhid->rd_size)) {
362 ret = -EFAULT;
363 goto err_free;
364 }
365
366 hid = hid_allocate_device();
367 if (IS_ERR(hid)) {
368 ret = PTR_ERR(hid);
369 goto err_free;
370 }
371
372 strncpy(hid->name, ev->u.create.name, 127);
373 hid->name[127] = 0;
374 strncpy(hid->phys, ev->u.create.phys, 63);
375 hid->phys[63] = 0;
376 strncpy(hid->uniq, ev->u.create.uniq, 63);
377 hid->uniq[63] = 0;
378
379 hid->ll_driver = &uhid_hid_driver;
380 hid->hid_get_raw_report = uhid_hid_get_raw;
381 hid->hid_output_raw_report = uhid_hid_output_raw;
382 hid->bus = ev->u.create.bus;
383 hid->vendor = ev->u.create.vendor;
384 hid->product = ev->u.create.product;
385 hid->version = ev->u.create.version;
386 hid->country = ev->u.create.country;
387 hid->driver_data = uhid;
388 hid->dev.parent = uhid_misc.this_device;
389
390 uhid->hid = hid;
391 uhid->running = true;
392
393 ret = hid_add_device(hid);
394 if (ret) {
395 hid_err(hid, "Cannot register HID device\n");
396 goto err_hid;
397 }
398
399 return 0;
400
401err_hid:
402 hid_destroy_device(hid);
403 uhid->hid = NULL;
404 uhid->running = false;
405err_free:
406 kfree(uhid->rd_data);
407 return ret;
408}
409
410static int uhid_dev_destroy(struct uhid_device *uhid)
411{
412 if (!uhid->running)
413 return -EINVAL;
414
David Herrmannfcfcf0d2012-06-10 15:16:25 +0200415 /* clear "running" before setting "report_done" */
David Herrmannd365c6c2012-06-10 15:16:18 +0200416 uhid->running = false;
David Herrmannfcfcf0d2012-06-10 15:16:25 +0200417 smp_wmb();
418 atomic_set(&uhid->report_done, 1);
419 wake_up_interruptible(&uhid->report_wait);
David Herrmannd365c6c2012-06-10 15:16:18 +0200420
421 hid_destroy_device(uhid->hid);
422 kfree(uhid->rd_data);
423
424 return 0;
425}
426
David Herrmann5e87a362012-06-10 15:16:19 +0200427static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
428{
429 if (!uhid->running)
430 return -EINVAL;
431
432 hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
433 min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
434
435 return 0;
436}
437
David Herrmannfcfcf0d2012-06-10 15:16:25 +0200438static int uhid_dev_feature_answer(struct uhid_device *uhid,
439 struct uhid_event *ev)
440{
441 unsigned long flags;
442
443 if (!uhid->running)
444 return -EINVAL;
445
446 spin_lock_irqsave(&uhid->qlock, flags);
447
448 /* id for old report; drop it silently */
449 if (atomic_read(&uhid->report_id) != ev->u.feature_answer.id)
450 goto unlock;
451 if (atomic_read(&uhid->report_done))
452 goto unlock;
453
454 memcpy(&uhid->report_buf, ev, sizeof(*ev));
455 atomic_set(&uhid->report_done, 1);
456 wake_up_interruptible(&uhid->report_wait);
457
458unlock:
459 spin_unlock_irqrestore(&uhid->qlock, flags);
460 return 0;
461}
462
David Herrmann1ccd7a22012-06-10 15:16:13 +0200463static int uhid_char_open(struct inode *inode, struct file *file)
464{
David Herrmannace3d862012-06-10 15:16:14 +0200465 struct uhid_device *uhid;
466
467 uhid = kzalloc(sizeof(*uhid), GFP_KERNEL);
468 if (!uhid)
469 return -ENOMEM;
470
David Herrmannd937ae52012-06-10 15:16:16 +0200471 mutex_init(&uhid->devlock);
David Herrmannfcfcf0d2012-06-10 15:16:25 +0200472 mutex_init(&uhid->report_lock);
David Herrmannace3d862012-06-10 15:16:14 +0200473 spin_lock_init(&uhid->qlock);
474 init_waitqueue_head(&uhid->waitq);
David Herrmannfcfcf0d2012-06-10 15:16:25 +0200475 init_waitqueue_head(&uhid->report_wait);
David Herrmannd365c6c2012-06-10 15:16:18 +0200476 uhid->running = false;
David Herrmannfcfcf0d2012-06-10 15:16:25 +0200477 atomic_set(&uhid->report_done, 1);
David Herrmannace3d862012-06-10 15:16:14 +0200478
479 file->private_data = uhid;
480 nonseekable_open(inode, file);
481
David Herrmann1ccd7a22012-06-10 15:16:13 +0200482 return 0;
483}
484
485static int uhid_char_release(struct inode *inode, struct file *file)
486{
David Herrmannace3d862012-06-10 15:16:14 +0200487 struct uhid_device *uhid = file->private_data;
488 unsigned int i;
489
David Herrmannd365c6c2012-06-10 15:16:18 +0200490 uhid_dev_destroy(uhid);
491
David Herrmannace3d862012-06-10 15:16:14 +0200492 for (i = 0; i < UHID_BUFSIZE; ++i)
493 kfree(uhid->outq[i]);
494
495 kfree(uhid);
496
David Herrmann1ccd7a22012-06-10 15:16:13 +0200497 return 0;
498}
499
500static ssize_t uhid_char_read(struct file *file, char __user *buffer,
501 size_t count, loff_t *ppos)
502{
David Herrmannd937ae52012-06-10 15:16:16 +0200503 struct uhid_device *uhid = file->private_data;
504 int ret;
505 unsigned long flags;
506 size_t len;
507
508 /* they need at least the "type" member of uhid_event */
509 if (count < sizeof(__u32))
510 return -EINVAL;
511
512try_again:
513 if (file->f_flags & O_NONBLOCK) {
514 if (uhid->head == uhid->tail)
515 return -EAGAIN;
516 } else {
517 ret = wait_event_interruptible(uhid->waitq,
518 uhid->head != uhid->tail);
519 if (ret)
520 return ret;
521 }
522
523 ret = mutex_lock_interruptible(&uhid->devlock);
524 if (ret)
525 return ret;
526
527 if (uhid->head == uhid->tail) {
528 mutex_unlock(&uhid->devlock);
529 goto try_again;
530 } else {
531 len = min(count, sizeof(**uhid->outq));
Vinicius Costa Gomesadefb692012-07-14 18:59:25 -0300532 if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) {
David Herrmannd937ae52012-06-10 15:16:16 +0200533 ret = -EFAULT;
534 } else {
535 kfree(uhid->outq[uhid->tail]);
536 uhid->outq[uhid->tail] = NULL;
537
538 spin_lock_irqsave(&uhid->qlock, flags);
539 uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE;
540 spin_unlock_irqrestore(&uhid->qlock, flags);
541 }
542 }
543
544 mutex_unlock(&uhid->devlock);
545 return ret ? ret : len;
David Herrmann1ccd7a22012-06-10 15:16:13 +0200546}
547
548static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
549 size_t count, loff_t *ppos)
550{
David Herrmann6664ef72012-06-10 15:16:17 +0200551 struct uhid_device *uhid = file->private_data;
552 int ret;
553 size_t len;
554
555 /* we need at least the "type" member of uhid_event */
556 if (count < sizeof(__u32))
557 return -EINVAL;
558
559 ret = mutex_lock_interruptible(&uhid->devlock);
560 if (ret)
561 return ret;
562
563 memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
564 len = min(count, sizeof(uhid->input_buf));
Dmitry Torokhovbefde022013-02-18 11:26:11 +0100565
566 ret = uhid_event_from_user(buffer, len, &uhid->input_buf);
567 if (ret)
David Herrmann6664ef72012-06-10 15:16:17 +0200568 goto unlock;
David Herrmann6664ef72012-06-10 15:16:17 +0200569
570 switch (uhid->input_buf.type) {
David Herrmannd365c6c2012-06-10 15:16:18 +0200571 case UHID_CREATE:
572 ret = uhid_dev_create(uhid, &uhid->input_buf);
573 break;
574 case UHID_DESTROY:
575 ret = uhid_dev_destroy(uhid);
576 break;
David Herrmann5e87a362012-06-10 15:16:19 +0200577 case UHID_INPUT:
578 ret = uhid_dev_input(uhid, &uhid->input_buf);
579 break;
David Herrmannfcfcf0d2012-06-10 15:16:25 +0200580 case UHID_FEATURE_ANSWER:
581 ret = uhid_dev_feature_answer(uhid, &uhid->input_buf);
582 break;
David Herrmann6664ef72012-06-10 15:16:17 +0200583 default:
584 ret = -EOPNOTSUPP;
585 }
586
587unlock:
588 mutex_unlock(&uhid->devlock);
589
590 /* return "count" not "len" to not confuse the caller */
591 return ret ? ret : count;
David Herrmann1ccd7a22012-06-10 15:16:13 +0200592}
593
594static unsigned int uhid_char_poll(struct file *file, poll_table *wait)
595{
David Herrmann1f9dec12012-06-10 15:16:15 +0200596 struct uhid_device *uhid = file->private_data;
597
598 poll_wait(file, &uhid->waitq, wait);
599
600 if (uhid->head != uhid->tail)
601 return POLLIN | POLLRDNORM;
602
David Herrmann1ccd7a22012-06-10 15:16:13 +0200603 return 0;
604}
605
606static const struct file_operations uhid_fops = {
607 .owner = THIS_MODULE,
608 .open = uhid_char_open,
609 .release = uhid_char_release,
610 .read = uhid_char_read,
611 .write = uhid_char_write,
612 .poll = uhid_char_poll,
613 .llseek = no_llseek,
614};
615
616static struct miscdevice uhid_misc = {
617 .fops = &uhid_fops,
David Herrmann19872d22013-09-09 18:33:54 +0200618 .minor = UHID_MINOR,
David Herrmann1ccd7a22012-06-10 15:16:13 +0200619 .name = UHID_NAME,
620};
621
622static int __init uhid_init(void)
623{
624 return misc_register(&uhid_misc);
625}
626
627static void __exit uhid_exit(void)
628{
629 misc_deregister(&uhid_misc);
630}
631
632module_init(uhid_init);
633module_exit(uhid_exit);
634MODULE_LICENSE("GPL");
635MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
636MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");
David Herrmann19872d22013-09-09 18:33:54 +0200637MODULE_ALIAS_MISCDEV(UHID_MINOR);
Marcel Holtmann60cbd532013-09-01 11:02:46 -0700638MODULE_ALIAS("devname:" UHID_NAME);