2 * HID raw devices, giving access to raw HID events.
4 * In comparison to hiddev, this device does not process the
5 * hid events at all (no parsing, no lookups). This lets applications
6 * to work on raw hid events as they want to, and avoids a need to
7 * use a transport-specific userspace libhid/libusb libraries.
9 * Copyright (c) 2007-2014 Jiri Kosina
13 * This program is free software; you can redistribute it and/or modify it
14 * under the terms and conditions of the GNU General Public License,
15 * version 2, as published by the Free Software Foundation.
17 * You should have received a copy of the GNU General Public License along with
18 * this program; if not, write to the Free Software Foundation, Inc.,
19 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25 #include <linux/module.h>
26 #include <linux/errno.h>
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/cdev.h>
30 #include <linux/poll.h>
31 #include <linux/device.h>
32 #include <linux/major.h>
33 #include <linux/slab.h>
34 #include <linux/hid.h>
35 #include <linux/mutex.h>
36 #include <linux/sched/signal.h>
37 #include <linux/string.h>
39 #include <linux/hidraw.h>
41 static int hidraw_major;
42 static struct cdev hidraw_cdev;
43 static struct class *hidraw_class;
44 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
45 static DEFINE_MUTEX(minors_lock);
47 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
49 struct hidraw_list *list = file->private_data;
51 DECLARE_WAITQUEUE(wait, current);
53 mutex_lock(&list->read_mutex);
56 if (list->head == list->tail) {
57 add_wait_queue(&list->hidraw->wait, &wait);
58 set_current_state(TASK_INTERRUPTIBLE);
60 while (list->head == list->tail) {
61 if (signal_pending(current)) {
65 if (!list->hidraw->exist) {
69 if (file->f_flags & O_NONBLOCK) {
74 /* allow O_NONBLOCK to work well from other threads */
75 mutex_unlock(&list->read_mutex);
77 mutex_lock(&list->read_mutex);
78 set_current_state(TASK_INTERRUPTIBLE);
81 set_current_state(TASK_RUNNING);
82 remove_wait_queue(&list->hidraw->wait, &wait);
88 len = list->buffer[list->tail].len > count ?
89 count : list->buffer[list->tail].len;
91 if (list->buffer[list->tail].value) {
92 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
99 kfree(list->buffer[list->tail].value);
100 list->buffer[list->tail].value = NULL;
101 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
104 mutex_unlock(&list->read_mutex);
109 * The first byte of the report buffer is expected to be a report number.
111 * This function is to be called with the minors_lock mutex held.
113 static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
115 unsigned int minor = iminor(file_inode(file));
116 struct hid_device *dev;
120 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
125 dev = hidraw_table[minor]->hid;
127 if (count > HID_MAX_BUFFER_SIZE) {
128 hid_warn(dev, "pid %d passed too large report\n",
129 task_pid_nr(current));
135 hid_warn(dev, "pid %d passed too short report\n",
136 task_pid_nr(current));
141 buf = memdup_user(buffer, count);
147 if ((report_type == HID_OUTPUT_REPORT) &&
148 !(dev->quirks & HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP)) {
149 ret = hid_hw_output_report(dev, buf, count);
151 * compatibility with old implementation of USB-HID and I2C-HID:
152 * if the device does not support receiving output reports,
153 * on an interrupt endpoint, fallback to SET_REPORT HID command.
159 ret = hid_hw_raw_request(dev, buf[0], buf, count, report_type,
168 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
171 mutex_lock(&minors_lock);
172 ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
173 mutex_unlock(&minors_lock);
179 * This function performs a Get_Report transfer over the control endpoint
180 * per section 7.2.1 of the HID specification, version 1.1. The first byte
181 * of buffer is the report number to request, or 0x0 if the defice does not
182 * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
183 * or HID_INPUT_REPORT.
185 * This function is to be called with the minors_lock mutex held.
187 static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
189 unsigned int minor = iminor(file_inode(file));
190 struct hid_device *dev;
193 unsigned char report_number;
195 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
200 dev = hidraw_table[minor]->hid;
202 if (!dev->ll_driver->raw_request) {
207 if (count > HID_MAX_BUFFER_SIZE) {
208 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
209 task_pid_nr(current));
215 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
216 task_pid_nr(current));
221 buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
228 * Read the first byte from the user. This is the report number,
229 * which is passed to hid_hw_raw_request().
231 if (copy_from_user(&report_number, buffer, 1)) {
236 ret = hid_hw_raw_request(dev, report_number, buf, count, report_type,
242 len = (ret < count) ? ret : count;
244 if (copy_to_user(buffer, buf, len)) {
257 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
259 struct hidraw_list *list = file->private_data;
260 unsigned int mask = POLLOUT | POLLWRNORM; /* hidraw is always writable */
262 poll_wait(file, &list->hidraw->wait, wait);
263 if (list->head != list->tail)
264 mask |= POLLIN | POLLRDNORM;
265 if (!list->hidraw->exist)
266 mask |= POLLERR | POLLHUP;
270 static int hidraw_open(struct inode *inode, struct file *file)
272 unsigned int minor = iminor(inode);
274 struct hidraw_list *list;
278 if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
283 mutex_lock(&minors_lock);
284 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
289 dev = hidraw_table[minor];
291 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
297 err = hid_hw_open(dev->hid);
299 hid_hw_power(dev->hid, PM_HINT_NORMAL);
305 list->hidraw = hidraw_table[minor];
306 mutex_init(&list->read_mutex);
307 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
308 list_add_tail(&list->node, &hidraw_table[minor]->list);
309 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
310 file->private_data = list;
312 mutex_unlock(&minors_lock);
320 static int hidraw_fasync(int fd, struct file *file, int on)
322 struct hidraw_list *list = file->private_data;
324 return fasync_helper(fd, file, on, &list->fasync);
327 static void drop_ref(struct hidraw *hidraw, int exists_bit)
332 hid_hw_close(hidraw->hid);
333 wake_up_interruptible(&hidraw->wait);
335 device_destroy(hidraw_class,
336 MKDEV(hidraw_major, hidraw->minor));
341 if (!hidraw->exist) {
342 hidraw_table[hidraw->minor] = NULL;
345 /* close device for last reader */
346 hid_hw_close(hidraw->hid);
347 hid_hw_power(hidraw->hid, PM_HINT_NORMAL);
352 static int hidraw_release(struct inode * inode, struct file * file)
354 unsigned int minor = iminor(inode);
355 struct hidraw_list *list = file->private_data;
359 mutex_lock(&minors_lock);
361 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
362 for (i = list->tail; i < list->head; i++)
363 kfree(list->buffer[i].value);
364 list_del(&list->node);
365 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
368 drop_ref(hidraw_table[minor], 0);
370 mutex_unlock(&minors_lock);
374 static long hidraw_ioctl(struct file *file, unsigned int cmd,
377 struct inode *inode = file_inode(file);
378 unsigned int minor = iminor(inode);
381 void __user *user_arg = (void __user*) arg;
383 mutex_lock(&minors_lock);
384 dev = hidraw_table[minor];
385 if (!dev || !dev->exist) {
391 case HIDIOCGRDESCSIZE:
392 if (put_user(dev->hid->rsize, (int __user *)arg))
400 if (get_user(len, (int __user *)arg))
402 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
404 else if (copy_to_user(user_arg + offsetof(
405 struct hidraw_report_descriptor,
408 min(dev->hid->rsize, len)))
414 struct hidraw_devinfo dinfo;
416 dinfo.bustype = dev->hid->bus;
417 dinfo.vendor = dev->hid->vendor;
418 dinfo.product = dev->hid->product;
419 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
425 struct hid_device *hid = dev->hid;
426 if (_IOC_TYPE(cmd) != 'H') {
431 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
432 int len = _IOC_SIZE(cmd);
433 ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
436 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
437 int len = _IOC_SIZE(cmd);
438 ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
442 /* Begin Read-only ioctls. */
443 if (_IOC_DIR(cmd) != _IOC_READ) {
448 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
449 int len = strlen(hid->name) + 1;
450 if (len > _IOC_SIZE(cmd))
451 len = _IOC_SIZE(cmd);
452 ret = copy_to_user(user_arg, hid->name, len) ?
457 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
458 int len = strlen(hid->phys) + 1;
459 if (len > _IOC_SIZE(cmd))
460 len = _IOC_SIZE(cmd);
461 ret = copy_to_user(user_arg, hid->phys, len) ?
470 mutex_unlock(&minors_lock);
474 static const struct file_operations hidraw_ops = {
475 .owner = THIS_MODULE,
477 .write = hidraw_write,
480 .release = hidraw_release,
481 .unlocked_ioctl = hidraw_ioctl,
482 .fasync = hidraw_fasync,
484 .compat_ioctl = hidraw_ioctl,
486 .llseek = noop_llseek,
489 int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
491 struct hidraw *dev = hid->hidraw;
492 struct hidraw_list *list;
496 spin_lock_irqsave(&dev->list_lock, flags);
497 list_for_each_entry(list, &dev->list, node) {
498 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
500 if (new_head == list->tail)
503 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
507 list->buffer[list->head].len = len;
508 list->head = new_head;
509 kill_fasync(&list->fasync, SIGIO, POLL_IN);
511 spin_unlock_irqrestore(&dev->list_lock, flags);
513 wake_up_interruptible(&dev->wait);
516 EXPORT_SYMBOL_GPL(hidraw_report_event);
518 int hidraw_connect(struct hid_device *hid)
523 /* we accept any HID device, all applications */
525 dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
531 mutex_lock(&minors_lock);
533 for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
534 if (hidraw_table[minor])
536 hidraw_table[minor] = dev;
542 mutex_unlock(&minors_lock);
547 dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
548 NULL, "%s%d", "hidraw", minor);
550 if (IS_ERR(dev->dev)) {
551 hidraw_table[minor] = NULL;
552 mutex_unlock(&minors_lock);
553 result = PTR_ERR(dev->dev);
558 init_waitqueue_head(&dev->wait);
559 spin_lock_init(&dev->list_lock);
560 INIT_LIST_HEAD(&dev->list);
568 mutex_unlock(&minors_lock);
573 EXPORT_SYMBOL_GPL(hidraw_connect);
575 void hidraw_disconnect(struct hid_device *hid)
577 struct hidraw *hidraw = hid->hidraw;
579 mutex_lock(&minors_lock);
583 mutex_unlock(&minors_lock);
585 EXPORT_SYMBOL_GPL(hidraw_disconnect);
587 int __init hidraw_init(void)
592 result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
593 HIDRAW_MAX_DEVICES, "hidraw");
595 pr_warn("can't get major number\n");
599 hidraw_major = MAJOR(dev_id);
601 hidraw_class = class_create(THIS_MODULE, "hidraw");
602 if (IS_ERR(hidraw_class)) {
603 result = PTR_ERR(hidraw_class);
607 cdev_init(&hidraw_cdev, &hidraw_ops);
608 result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
612 printk(KERN_INFO "hidraw: raw HID events driver (C) Jiri Kosina\n");
617 class_destroy(hidraw_class);
619 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
623 void hidraw_exit(void)
625 dev_t dev_id = MKDEV(hidraw_major, 0);
627 cdev_del(&hidraw_cdev);
628 class_destroy(hidraw_class);
629 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);