2 * User-space I/O driver support for HID subsystem
3 * Copyright (c) 2012 David Herrmann
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)
13 #include <linux/atomic.h>
14 #include <linux/compat.h>
15 #include <linux/device.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>
28 #define UHID_NAME "uhid"
29 #define UHID_BUFSIZE 32
38 struct hid_device *hid;
39 struct uhid_event input_buf;
41 wait_queue_head_t waitq;
45 struct uhid_event *outq[UHID_BUFSIZE];
47 struct mutex report_lock;
48 wait_queue_head_t report_wait;
51 struct uhid_event report_buf;
54 static struct miscdevice uhid_misc;
56 static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev)
60 newhead = (uhid->head + 1) % UHID_BUFSIZE;
62 if (newhead != uhid->tail) {
63 uhid->outq[uhid->head] = ev;
65 wake_up_interruptible(&uhid->waitq);
67 hid_warn(uhid->hid, "Output queue is full\n");
72 static int uhid_queue_event(struct uhid_device *uhid, __u32 event)
75 struct uhid_event *ev;
77 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
83 spin_lock_irqsave(&uhid->qlock, flags);
85 spin_unlock_irqrestore(&uhid->qlock, flags);
90 static int uhid_hid_start(struct hid_device *hid)
92 struct uhid_device *uhid = hid->driver_data;
94 return uhid_queue_event(uhid, UHID_START);
97 static void uhid_hid_stop(struct hid_device *hid)
99 struct uhid_device *uhid = hid->driver_data;
102 uhid_queue_event(uhid, UHID_STOP);
105 static int uhid_hid_open(struct hid_device *hid)
107 struct uhid_device *uhid = hid->driver_data;
109 return uhid_queue_event(uhid, UHID_OPEN);
112 static void uhid_hid_close(struct hid_device *hid)
114 struct uhid_device *uhid = hid->driver_data;
116 uhid_queue_event(uhid, UHID_CLOSE);
119 static int uhid_hid_parse(struct hid_device *hid)
121 struct uhid_device *uhid = hid->driver_data;
123 return hid_parse_report(hid, uhid->rd_data, uhid->rd_size);
126 static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum,
127 __u8 *buf, size_t count, unsigned char rtype)
129 struct uhid_device *uhid = hid->driver_data;
131 struct uhid_event *ev;
134 size_t uninitialized_var(len);
135 struct uhid_feature_answer_req *req;
141 case HID_FEATURE_REPORT:
142 report_type = UHID_FEATURE_REPORT;
144 case HID_OUTPUT_REPORT:
145 report_type = UHID_OUTPUT_REPORT;
147 case HID_INPUT_REPORT:
148 report_type = UHID_INPUT_REPORT;
154 ret = mutex_lock_interruptible(&uhid->report_lock);
158 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
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;
170 atomic_set(&uhid->report_done, 0);
171 uhid_queue(uhid, ev);
172 spin_unlock_irqrestore(&uhid->qlock, flags);
174 ret = wait_event_interruptible_timeout(uhid->report_wait,
175 atomic_read(&uhid->report_done) || !uhid->running,
178 if (!ret || !uhid->running) {
180 } else if (ret < 0) {
183 spin_lock_irqsave(&uhid->qlock, flags);
184 req = &uhid->report_buf.u.feature_answer;
191 min_t(size_t, req->size, UHID_DATA_MAX));
192 memcpy(buf, req->data, len);
195 spin_unlock_irqrestore(&uhid->qlock, flags);
198 atomic_set(&uhid->report_done, 1);
201 mutex_unlock(&uhid->report_lock);
202 return ret ? ret : len;
205 static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
206 unsigned char report_type)
208 struct uhid_device *uhid = hid->driver_data;
211 struct uhid_event *ev;
213 switch (report_type) {
214 case HID_FEATURE_REPORT:
215 rtype = UHID_FEATURE_REPORT;
217 case HID_OUTPUT_REPORT:
218 rtype = UHID_OUTPUT_REPORT;
224 if (count < 1 || count > UHID_DATA_MAX)
227 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
231 ev->type = UHID_OUTPUT;
232 ev->u.output.size = count;
233 ev->u.output.rtype = rtype;
234 memcpy(ev->u.output.data, buf, count);
236 spin_lock_irqsave(&uhid->qlock, flags);
237 uhid_queue(uhid, ev);
238 spin_unlock_irqrestore(&uhid->qlock, flags);
243 static int uhid_hid_output_report(struct hid_device *hid, __u8 *buf,
246 return uhid_hid_output_raw(hid, buf, count, HID_OUTPUT_REPORT);
249 static int uhid_raw_request(struct hid_device *hid, unsigned char reportnum,
250 __u8 *buf, size_t len, unsigned char rtype,
254 case HID_REQ_GET_REPORT:
255 return uhid_hid_get_raw(hid, reportnum, buf, len, rtype);
256 case HID_REQ_SET_REPORT:
257 /* TODO: implement proper SET_REPORT functionality */
264 static struct hid_ll_driver uhid_hid_driver = {
265 .start = uhid_hid_start,
266 .stop = uhid_hid_stop,
267 .open = uhid_hid_open,
268 .close = uhid_hid_close,
269 .parse = uhid_hid_parse,
270 .output_report = uhid_hid_output_report,
271 .raw_request = uhid_raw_request,
276 /* Apparently we haven't stepped on these rakes enough times yet. */
277 struct uhid_create_req_compat {
282 compat_uptr_t rd_data;
290 } __attribute__((__packed__));
292 static int uhid_event_from_user(const char __user *buffer, size_t len,
293 struct uhid_event *event)
295 if (is_compat_task()) {
298 if (get_user(type, buffer))
301 if (type == UHID_CREATE) {
303 * This is our messed up request with compat pointer.
304 * It is largish (more than 256 bytes) so we better
305 * allocate it from the heap.
307 struct uhid_create_req_compat *compat;
309 compat = kzalloc(sizeof(*compat), GFP_KERNEL);
313 buffer += sizeof(type);
315 if (copy_from_user(compat, buffer,
316 min(len, sizeof(*compat)))) {
321 /* Shuffle the data over to proper structure */
324 memcpy(event->u.create.name, compat->name,
325 sizeof(compat->name));
326 memcpy(event->u.create.phys, compat->phys,
327 sizeof(compat->phys));
328 memcpy(event->u.create.uniq, compat->uniq,
329 sizeof(compat->uniq));
331 event->u.create.rd_data = compat_ptr(compat->rd_data);
332 event->u.create.rd_size = compat->rd_size;
334 event->u.create.bus = compat->bus;
335 event->u.create.vendor = compat->vendor;
336 event->u.create.product = compat->product;
337 event->u.create.version = compat->version;
338 event->u.create.country = compat->country;
343 /* All others can be copied directly */
346 if (copy_from_user(event, buffer, min(len, sizeof(*event))))
352 static int uhid_event_from_user(const char __user *buffer, size_t len,
353 struct uhid_event *event)
355 if (copy_from_user(event, buffer, min(len, sizeof(*event))))
362 static int uhid_dev_create2(struct uhid_device *uhid,
363 const struct uhid_event *ev)
365 struct hid_device *hid;
373 rd_size = ev->u.create2.rd_size;
374 if (rd_size <= 0 || rd_size > HID_MAX_DESCRIPTOR_SIZE)
377 rd_data = kmemdup(ev->u.create2.rd_data, rd_size, GFP_KERNEL);
381 uhid->rd_size = rd_size;
382 uhid->rd_data = rd_data;
384 hid = hid_allocate_device();
390 strncpy(hid->name, ev->u.create2.name, 127);
392 strncpy(hid->phys, ev->u.create2.phys, 63);
394 strncpy(hid->uniq, ev->u.create2.uniq, 63);
397 hid->ll_driver = &uhid_hid_driver;
398 hid->bus = ev->u.create2.bus;
399 hid->vendor = ev->u.create2.vendor;
400 hid->product = ev->u.create2.product;
401 hid->version = ev->u.create2.version;
402 hid->country = ev->u.create2.country;
403 hid->driver_data = uhid;
404 hid->dev.parent = uhid_misc.this_device;
407 uhid->running = true;
409 ret = hid_add_device(hid);
411 hid_err(hid, "Cannot register HID device\n");
418 hid_destroy_device(hid);
420 uhid->running = false;
422 kfree(uhid->rd_data);
423 uhid->rd_data = NULL;
428 static int uhid_dev_create(struct uhid_device *uhid,
429 struct uhid_event *ev)
431 struct uhid_create_req orig;
435 if (orig.rd_size <= 0 || orig.rd_size > HID_MAX_DESCRIPTOR_SIZE)
437 if (copy_from_user(&ev->u.create2.rd_data, orig.rd_data, orig.rd_size))
440 memcpy(ev->u.create2.name, orig.name, sizeof(orig.name));
441 memcpy(ev->u.create2.phys, orig.phys, sizeof(orig.phys));
442 memcpy(ev->u.create2.uniq, orig.uniq, sizeof(orig.uniq));
443 ev->u.create2.rd_size = orig.rd_size;
444 ev->u.create2.bus = orig.bus;
445 ev->u.create2.vendor = orig.vendor;
446 ev->u.create2.product = orig.product;
447 ev->u.create2.version = orig.version;
448 ev->u.create2.country = orig.country;
450 return uhid_dev_create2(uhid, ev);
453 static int uhid_dev_destroy(struct uhid_device *uhid)
458 uhid->running = false;
459 wake_up_interruptible(&uhid->report_wait);
461 hid_destroy_device(uhid->hid);
462 kfree(uhid->rd_data);
467 static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
472 hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
473 min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
478 static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev)
483 hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data,
484 min_t(size_t, ev->u.input2.size, UHID_DATA_MAX), 0);
489 static int uhid_dev_feature_answer(struct uhid_device *uhid,
490 struct uhid_event *ev)
497 spin_lock_irqsave(&uhid->qlock, flags);
499 /* id for old report; drop it silently */
500 if (atomic_read(&uhid->report_id) != ev->u.feature_answer.id)
502 if (atomic_read(&uhid->report_done))
505 memcpy(&uhid->report_buf, ev, sizeof(*ev));
506 atomic_set(&uhid->report_done, 1);
507 wake_up_interruptible(&uhid->report_wait);
510 spin_unlock_irqrestore(&uhid->qlock, flags);
514 static int uhid_char_open(struct inode *inode, struct file *file)
516 struct uhid_device *uhid;
518 uhid = kzalloc(sizeof(*uhid), GFP_KERNEL);
522 mutex_init(&uhid->devlock);
523 mutex_init(&uhid->report_lock);
524 spin_lock_init(&uhid->qlock);
525 init_waitqueue_head(&uhid->waitq);
526 init_waitqueue_head(&uhid->report_wait);
527 uhid->running = false;
528 atomic_set(&uhid->report_done, 1);
530 file->private_data = uhid;
531 nonseekable_open(inode, file);
536 static int uhid_char_release(struct inode *inode, struct file *file)
538 struct uhid_device *uhid = file->private_data;
541 uhid_dev_destroy(uhid);
543 for (i = 0; i < UHID_BUFSIZE; ++i)
544 kfree(uhid->outq[i]);
551 static ssize_t uhid_char_read(struct file *file, char __user *buffer,
552 size_t count, loff_t *ppos)
554 struct uhid_device *uhid = file->private_data;
559 /* they need at least the "type" member of uhid_event */
560 if (count < sizeof(__u32))
564 if (file->f_flags & O_NONBLOCK) {
565 if (uhid->head == uhid->tail)
568 ret = wait_event_interruptible(uhid->waitq,
569 uhid->head != uhid->tail);
574 ret = mutex_lock_interruptible(&uhid->devlock);
578 if (uhid->head == uhid->tail) {
579 mutex_unlock(&uhid->devlock);
582 len = min(count, sizeof(**uhid->outq));
583 if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) {
586 kfree(uhid->outq[uhid->tail]);
587 uhid->outq[uhid->tail] = NULL;
589 spin_lock_irqsave(&uhid->qlock, flags);
590 uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE;
591 spin_unlock_irqrestore(&uhid->qlock, flags);
595 mutex_unlock(&uhid->devlock);
596 return ret ? ret : len;
599 static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
600 size_t count, loff_t *ppos)
602 struct uhid_device *uhid = file->private_data;
606 /* we need at least the "type" member of uhid_event */
607 if (count < sizeof(__u32))
610 ret = mutex_lock_interruptible(&uhid->devlock);
614 memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
615 len = min(count, sizeof(uhid->input_buf));
617 ret = uhid_event_from_user(buffer, len, &uhid->input_buf);
621 switch (uhid->input_buf.type) {
623 ret = uhid_dev_create(uhid, &uhid->input_buf);
626 ret = uhid_dev_create2(uhid, &uhid->input_buf);
629 ret = uhid_dev_destroy(uhid);
632 ret = uhid_dev_input(uhid, &uhid->input_buf);
635 ret = uhid_dev_input2(uhid, &uhid->input_buf);
637 case UHID_FEATURE_ANSWER:
638 ret = uhid_dev_feature_answer(uhid, &uhid->input_buf);
645 mutex_unlock(&uhid->devlock);
647 /* return "count" not "len" to not confuse the caller */
648 return ret ? ret : count;
651 static unsigned int uhid_char_poll(struct file *file, poll_table *wait)
653 struct uhid_device *uhid = file->private_data;
655 poll_wait(file, &uhid->waitq, wait);
657 if (uhid->head != uhid->tail)
658 return POLLIN | POLLRDNORM;
663 static const struct file_operations uhid_fops = {
664 .owner = THIS_MODULE,
665 .open = uhid_char_open,
666 .release = uhid_char_release,
667 .read = uhid_char_read,
668 .write = uhid_char_write,
669 .poll = uhid_char_poll,
673 static struct miscdevice uhid_misc = {
679 static int __init uhid_init(void)
681 return misc_register(&uhid_misc);
684 static void __exit uhid_exit(void)
686 misc_deregister(&uhid_misc);
689 module_init(uhid_init);
690 module_exit(uhid_exit);
691 MODULE_LICENSE("GPL");
692 MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
693 MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");
694 MODULE_ALIAS_MISCDEV(UHID_MINOR);
695 MODULE_ALIAS("devname:" UHID_NAME);