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), 5 * HZ);
178 * Make sure "uhid->running" is cleared on shutdown before
179 * "uhid->report_done" is set.
182 if (!ret || !uhid->running) {
184 } else if (ret < 0) {
187 spin_lock_irqsave(&uhid->qlock, flags);
188 req = &uhid->report_buf.u.feature_answer;
195 min_t(size_t, req->size, UHID_DATA_MAX));
196 memcpy(buf, req->data, len);
199 spin_unlock_irqrestore(&uhid->qlock, flags);
202 atomic_set(&uhid->report_done, 1);
205 mutex_unlock(&uhid->report_lock);
206 return ret ? ret : len;
209 static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
210 unsigned char report_type)
212 struct uhid_device *uhid = hid->driver_data;
215 struct uhid_event *ev;
217 switch (report_type) {
218 case HID_FEATURE_REPORT:
219 rtype = UHID_FEATURE_REPORT;
221 case HID_OUTPUT_REPORT:
222 rtype = UHID_OUTPUT_REPORT;
228 if (count < 1 || count > UHID_DATA_MAX)
231 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
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);
240 spin_lock_irqsave(&uhid->qlock, flags);
241 uhid_queue(uhid, ev);
242 spin_unlock_irqrestore(&uhid->qlock, flags);
247 static int uhid_hid_output_report(struct hid_device *hid, __u8 *buf,
250 struct uhid_device *uhid = hid->driver_data;
252 struct uhid_event *ev;
254 if (count < 1 || count > UHID_DATA_MAX)
257 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
261 ev->type = UHID_OUTPUT;
262 ev->u.output.size = count;
263 ev->u.output.rtype = UHID_OUTPUT_REPORT;
264 memcpy(ev->u.output.data, buf, count);
266 spin_lock_irqsave(&uhid->qlock, flags);
267 uhid_queue(uhid, ev);
268 spin_unlock_irqrestore(&uhid->qlock, flags);
273 static struct hid_ll_driver uhid_hid_driver = {
274 .start = uhid_hid_start,
275 .stop = uhid_hid_stop,
276 .open = uhid_hid_open,
277 .close = uhid_hid_close,
278 .parse = uhid_hid_parse,
279 .output_report = uhid_hid_output_report,
284 /* Apparently we haven't stepped on these rakes enough times yet. */
285 struct uhid_create_req_compat {
290 compat_uptr_t rd_data;
298 } __attribute__((__packed__));
300 static int uhid_event_from_user(const char __user *buffer, size_t len,
301 struct uhid_event *event)
303 if (is_compat_task()) {
306 if (get_user(type, buffer))
309 if (type == UHID_CREATE) {
311 * This is our messed up request with compat pointer.
312 * It is largish (more than 256 bytes) so we better
313 * allocate it from the heap.
315 struct uhid_create_req_compat *compat;
317 compat = kzalloc(sizeof(*compat), GFP_KERNEL);
321 buffer += sizeof(type);
323 if (copy_from_user(compat, buffer,
324 min(len, sizeof(*compat)))) {
329 /* Shuffle the data over to proper structure */
332 memcpy(event->u.create.name, compat->name,
333 sizeof(compat->name));
334 memcpy(event->u.create.phys, compat->phys,
335 sizeof(compat->phys));
336 memcpy(event->u.create.uniq, compat->uniq,
337 sizeof(compat->uniq));
339 event->u.create.rd_data = compat_ptr(compat->rd_data);
340 event->u.create.rd_size = compat->rd_size;
342 event->u.create.bus = compat->bus;
343 event->u.create.vendor = compat->vendor;
344 event->u.create.product = compat->product;
345 event->u.create.version = compat->version;
346 event->u.create.country = compat->country;
351 /* All others can be copied directly */
354 if (copy_from_user(event, buffer, min(len, sizeof(*event))))
360 static int uhid_event_from_user(const char __user *buffer, size_t len,
361 struct uhid_event *event)
363 if (copy_from_user(event, buffer, min(len, sizeof(*event))))
370 static int uhid_dev_create(struct uhid_device *uhid,
371 const struct uhid_event *ev)
373 struct hid_device *hid;
379 uhid->rd_size = ev->u.create.rd_size;
380 if (uhid->rd_size <= 0 || uhid->rd_size > HID_MAX_DESCRIPTOR_SIZE)
383 uhid->rd_data = kmalloc(uhid->rd_size, GFP_KERNEL);
387 if (copy_from_user(uhid->rd_data, ev->u.create.rd_data,
393 hid = hid_allocate_device();
399 strncpy(hid->name, ev->u.create.name, 127);
401 strncpy(hid->phys, ev->u.create.phys, 63);
403 strncpy(hid->uniq, ev->u.create.uniq, 63);
406 hid->ll_driver = &uhid_hid_driver;
407 hid->hid_output_raw_report = uhid_hid_output_raw;
408 hid->bus = ev->u.create.bus;
409 hid->vendor = ev->u.create.vendor;
410 hid->product = ev->u.create.product;
411 hid->version = ev->u.create.version;
412 hid->country = ev->u.create.country;
413 hid->driver_data = uhid;
414 hid->dev.parent = uhid_misc.this_device;
417 uhid->running = true;
419 ret = hid_add_device(hid);
421 hid_err(hid, "Cannot register HID device\n");
428 hid_destroy_device(hid);
430 uhid->running = false;
432 kfree(uhid->rd_data);
436 static int uhid_dev_destroy(struct uhid_device *uhid)
441 /* clear "running" before setting "report_done" */
442 uhid->running = false;
444 atomic_set(&uhid->report_done, 1);
445 wake_up_interruptible(&uhid->report_wait);
447 hid_destroy_device(uhid->hid);
448 kfree(uhid->rd_data);
453 static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
458 hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
459 min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
464 static int uhid_dev_feature_answer(struct uhid_device *uhid,
465 struct uhid_event *ev)
472 spin_lock_irqsave(&uhid->qlock, flags);
474 /* id for old report; drop it silently */
475 if (atomic_read(&uhid->report_id) != ev->u.feature_answer.id)
477 if (atomic_read(&uhid->report_done))
480 memcpy(&uhid->report_buf, ev, sizeof(*ev));
481 atomic_set(&uhid->report_done, 1);
482 wake_up_interruptible(&uhid->report_wait);
485 spin_unlock_irqrestore(&uhid->qlock, flags);
489 static int uhid_char_open(struct inode *inode, struct file *file)
491 struct uhid_device *uhid;
493 uhid = kzalloc(sizeof(*uhid), GFP_KERNEL);
497 mutex_init(&uhid->devlock);
498 mutex_init(&uhid->report_lock);
499 spin_lock_init(&uhid->qlock);
500 init_waitqueue_head(&uhid->waitq);
501 init_waitqueue_head(&uhid->report_wait);
502 uhid->running = false;
503 atomic_set(&uhid->report_done, 1);
505 file->private_data = uhid;
506 nonseekable_open(inode, file);
511 static int uhid_char_release(struct inode *inode, struct file *file)
513 struct uhid_device *uhid = file->private_data;
516 uhid_dev_destroy(uhid);
518 for (i = 0; i < UHID_BUFSIZE; ++i)
519 kfree(uhid->outq[i]);
526 static ssize_t uhid_char_read(struct file *file, char __user *buffer,
527 size_t count, loff_t *ppos)
529 struct uhid_device *uhid = file->private_data;
534 /* they need at least the "type" member of uhid_event */
535 if (count < sizeof(__u32))
539 if (file->f_flags & O_NONBLOCK) {
540 if (uhid->head == uhid->tail)
543 ret = wait_event_interruptible(uhid->waitq,
544 uhid->head != uhid->tail);
549 ret = mutex_lock_interruptible(&uhid->devlock);
553 if (uhid->head == uhid->tail) {
554 mutex_unlock(&uhid->devlock);
557 len = min(count, sizeof(**uhid->outq));
558 if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) {
561 kfree(uhid->outq[uhid->tail]);
562 uhid->outq[uhid->tail] = NULL;
564 spin_lock_irqsave(&uhid->qlock, flags);
565 uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE;
566 spin_unlock_irqrestore(&uhid->qlock, flags);
570 mutex_unlock(&uhid->devlock);
571 return ret ? ret : len;
574 static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
575 size_t count, loff_t *ppos)
577 struct uhid_device *uhid = file->private_data;
581 /* we need at least the "type" member of uhid_event */
582 if (count < sizeof(__u32))
585 ret = mutex_lock_interruptible(&uhid->devlock);
589 memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
590 len = min(count, sizeof(uhid->input_buf));
592 ret = uhid_event_from_user(buffer, len, &uhid->input_buf);
596 switch (uhid->input_buf.type) {
598 ret = uhid_dev_create(uhid, &uhid->input_buf);
601 ret = uhid_dev_destroy(uhid);
604 ret = uhid_dev_input(uhid, &uhid->input_buf);
606 case UHID_FEATURE_ANSWER:
607 ret = uhid_dev_feature_answer(uhid, &uhid->input_buf);
614 mutex_unlock(&uhid->devlock);
616 /* return "count" not "len" to not confuse the caller */
617 return ret ? ret : count;
620 static unsigned int uhid_char_poll(struct file *file, poll_table *wait)
622 struct uhid_device *uhid = file->private_data;
624 poll_wait(file, &uhid->waitq, wait);
626 if (uhid->head != uhid->tail)
627 return POLLIN | POLLRDNORM;
632 static const struct file_operations uhid_fops = {
633 .owner = THIS_MODULE,
634 .open = uhid_char_open,
635 .release = uhid_char_release,
636 .read = uhid_char_read,
637 .write = uhid_char_write,
638 .poll = uhid_char_poll,
642 static struct miscdevice uhid_misc = {
648 static int __init uhid_init(void)
650 return misc_register(&uhid_misc);
653 static void __exit uhid_exit(void)
655 misc_deregister(&uhid_misc);
658 module_init(uhid_init);
659 module_exit(uhid_exit);
660 MODULE_LICENSE("GPL");
661 MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
662 MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");
663 MODULE_ALIAS_MISCDEV(UHID_MINOR);
664 MODULE_ALIAS("devname:" UHID_NAME);