Fixed MTP to work with TWRP

drivers/hid/usbhid/hiddev.c

@@ -0,0 +1,939 @@
+/*
+ *  Copyright (c) 2001 Paul Stewart
+ *  Copyright (c) 2001 Vojtech Pavlik
+ *
+ *  HID char devices, giving access to raw HID device events.
+ *
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Should you need to contact me, the author, you can do so either by
+ * e-mail - mail your message to Paul Stewart <stewart@wetlogic.net>
+ */
+
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/usb.h>
+#include <linux/hid.h>
+#include <linux/hiddev.h>
+#include <linux/compat.h>
+#include <linux/vmalloc.h>
+#include "usbhid.h"
+
+#ifdef CONFIG_USB_DYNAMIC_MINORS
+#define HIDDEV_MINOR_BASE	0
+#define HIDDEV_MINORS		256
+#else
+#define HIDDEV_MINOR_BASE	96
+#define HIDDEV_MINORS		16
+#endif
+#define HIDDEV_BUFFER_SIZE	2048
+
+struct hiddev {
+	int exist;
+	int open;
+	struct mutex existancelock;
+	wait_queue_head_t wait;
+	struct hid_device *hid;
+	struct list_head list;
+	spinlock_t list_lock;
+};
+
+struct hiddev_list {
+	struct hiddev_usage_ref buffer[HIDDEV_BUFFER_SIZE];
+	int head;
+	int tail;
+	unsigned flags;
+	struct fasync_struct *fasync;
+	struct hiddev *hiddev;
+	struct list_head node;
+	struct mutex thread_lock;
+};
+
+/*
+ * Find a report, given the report's type and ID.  The ID can be specified
+ * indirectly by REPORT_ID_FIRST (which returns the first report of the given
+ * type) or by (REPORT_ID_NEXT | old_id), which returns the next report of the
+ * given type which follows old_id.
+ */
+static struct hid_report *
+hiddev_lookup_report(struct hid_device *hid, struct hiddev_report_info *rinfo)
+{
+	unsigned int flags = rinfo->report_id & ~HID_REPORT_ID_MASK;
+	unsigned int rid = rinfo->report_id & HID_REPORT_ID_MASK;
+	struct hid_report_enum *report_enum;
+	struct hid_report *report;
+	struct list_head *list;
+
+	if (rinfo->report_type < HID_REPORT_TYPE_MIN ||
+	    rinfo->report_type > HID_REPORT_TYPE_MAX)
+		return NULL;
+
+	report_enum = hid->report_enum +
+		(rinfo->report_type - HID_REPORT_TYPE_MIN);
+
+	switch (flags) {
+	case 0: /* Nothing to do -- report_id is already set correctly */
+		break;
+
+	case HID_REPORT_ID_FIRST:
+		if (list_empty(&report_enum->report_list))
+			return NULL;
+
+		list = report_enum->report_list.next;
+		report = list_entry(list, struct hid_report, list);
+		rinfo->report_id = report->id;
+		break;
+
+	case HID_REPORT_ID_NEXT:
+		report = report_enum->report_id_hash[rid];
+		if (!report)
+			return NULL;
+
+		list = report->list.next;
+		if (list == &report_enum->report_list)
+			return NULL;
+
+		report = list_entry(list, struct hid_report, list);
+		rinfo->report_id = report->id;
+		break;
+
+	default:
+		return NULL;
+	}
+
+	return report_enum->report_id_hash[rinfo->report_id];
+}
+
+/*
+ * Perform an exhaustive search of the report table for a usage, given its
+ * type and usage id.
+ */
+static struct hid_field *
+hiddev_lookup_usage(struct hid_device *hid, struct hiddev_usage_ref *uref)
+{
+	int i, j;
+	struct hid_report *report;
+	struct hid_report_enum *report_enum;
+	struct hid_field *field;
+
+	if (uref->report_type < HID_REPORT_TYPE_MIN ||
+	    uref->report_type > HID_REPORT_TYPE_MAX)
+		return NULL;
+
+	report_enum = hid->report_enum +
+		(uref->report_type - HID_REPORT_TYPE_MIN);
+
+	list_for_each_entry(report, &report_enum->report_list, list) {
+		for (i = 0; i < report->maxfield; i++) {
+			field = report->field[i];
+			for (j = 0; j < field->maxusage; j++) {
+				if (field->usage[j].hid == uref->usage_code) {
+					uref->report_id = report->id;
+					uref->field_index = i;
+					uref->usage_index = j;
+					return field;
+				}
+			}
+		}
+	}
+
+	return NULL;
+}
+
+static void hiddev_send_event(struct hid_device *hid,
+			      struct hiddev_usage_ref *uref)
+{
+	struct hiddev *hiddev = hid->hiddev;
+	struct hiddev_list *list;
+	unsigned long flags;
+
+	spin_lock_irqsave(&hiddev->list_lock, flags);
+	list_for_each_entry(list, &hiddev->list, node) {
+		if (uref->field_index != HID_FIELD_INDEX_NONE ||
+		    (list->flags & HIDDEV_FLAG_REPORT) != 0) {
+			list->buffer[list->head] = *uref;
+			list->head = (list->head + 1) &
+				(HIDDEV_BUFFER_SIZE - 1);
+			kill_fasync(&list->fasync, SIGIO, POLL_IN);
+		}
+	}
+	spin_unlock_irqrestore(&hiddev->list_lock, flags);
+
+	wake_up_interruptible(&hiddev->wait);
+}
+
+/*
+ * This is where hid.c calls into hiddev to pass an event that occurred over
+ * the interrupt pipe
+ */
+void hiddev_hid_event(struct hid_device *hid, struct hid_field *field,
+		      struct hid_usage *usage, __s32 value)
+{
+	unsigned type = field->report_type;
+	struct hiddev_usage_ref uref;
+
+	uref.report_type =
+	  (type == HID_INPUT_REPORT) ? HID_REPORT_TYPE_INPUT :
+	  ((type == HID_OUTPUT_REPORT) ? HID_REPORT_TYPE_OUTPUT :
+	   ((type == HID_FEATURE_REPORT) ? HID_REPORT_TYPE_FEATURE : 0));
+	uref.report_id = field->report->id;
+	uref.field_index = field->index;
+	uref.usage_index = (usage - field->usage);
+	uref.usage_code = usage->hid;
+	uref.value = value;
+
+	hiddev_send_event(hid, &uref);
+}
+EXPORT_SYMBOL_GPL(hiddev_hid_event);
+
+void hiddev_report_event(struct hid_device *hid, struct hid_report *report)
+{
+	unsigned type = report->type;
+	struct hiddev_usage_ref uref;
+
+	memset(&uref, 0, sizeof(uref));
+	uref.report_type =
+	  (type == HID_INPUT_REPORT) ? HID_REPORT_TYPE_INPUT :
+	  ((type == HID_OUTPUT_REPORT) ? HID_REPORT_TYPE_OUTPUT :
+	   ((type == HID_FEATURE_REPORT) ? HID_REPORT_TYPE_FEATURE : 0));
+	uref.report_id = report->id;
+	uref.field_index = HID_FIELD_INDEX_NONE;
+
+	hiddev_send_event(hid, &uref);
+}
+
+/*
+ * fasync file op
+ */
+static int hiddev_fasync(int fd, struct file *file, int on)
+{
+	struct hiddev_list *list = file->private_data;
+
+	return fasync_helper(fd, file, on, &list->fasync);
+}
+
+
+/*
+ * release file op
+ */
+static int hiddev_release(struct inode * inode, struct file * file)
+{
+	struct hiddev_list *list = file->private_data;
+	unsigned long flags;
+
+	spin_lock_irqsave(&list->hiddev->list_lock, flags);
+	list_del(&list->node);
+	spin_unlock_irqrestore(&list->hiddev->list_lock, flags);
+
+	mutex_lock(&list->hiddev->existancelock);
+	if (!--list->hiddev->open) {
+		if (list->hiddev->exist) {
+			usbhid_close(list->hiddev->hid);
+			usbhid_put_power(list->hiddev->hid);
+		} else {
+			mutex_unlock(&list->hiddev->existancelock);
+			kfree(list->hiddev);
+			vfree(list);
+			return 0;
+		}
+	}
+
+	mutex_unlock(&list->hiddev->existancelock);
+	vfree(list);
+
+	return 0;
+}
+
+/*
+ * open file op
+ */
+static int hiddev_open(struct inode *inode, struct file *file)
+{
+	struct hiddev_list *list;
+	struct usb_interface *intf;
+	struct hid_device *hid;
+	struct hiddev *hiddev;
+	int res;
+
+	intf = usbhid_find_interface(iminor(inode));
+	if (!intf)
+		return -ENODEV;
+	hid = usb_get_intfdata(intf);
+	hiddev = hid->hiddev;
+
+	if (!(list = vzalloc(sizeof(struct hiddev_list))))
+		return -ENOMEM;
+	mutex_init(&list->thread_lock);
+	list->hiddev = hiddev;
+	file->private_data = list;
+
+	/*
+	 * no need for locking because the USB major number
+	 * is shared which usbcore guards against disconnect
+	 */
+	if (list->hiddev->exist) {
+		if (!list->hiddev->open++) {
+			res = usbhid_open(hiddev->hid);
+			if (res < 0) {
+				res = -EIO;
+				goto bail;
+			}
+		}
+	} else {
+		res = -ENODEV;
+		goto bail;
+	}
+
+	spin_lock_irq(&list->hiddev->list_lock);
+	list_add_tail(&list->node, &hiddev->list);
+	spin_unlock_irq(&list->hiddev->list_lock);
+
+	mutex_lock(&hiddev->existancelock);
+	if (!list->hiddev->open++)
+		if (list->hiddev->exist) {
+			struct hid_device *hid = hiddev->hid;
+			res = usbhid_get_power(hid);
+			if (res < 0) {
+				res = -EIO;
+				goto bail_unlock;
+			}
+			usbhid_open(hid);
+		}
+	mutex_unlock(&hiddev->existancelock);
+	return 0;
+bail_unlock:
+	mutex_unlock(&hiddev->existancelock);
+bail:
+	file->private_data = NULL;
+	vfree(list);
+	return res;
+}
+
+/*
+ * "write" file op
+ */
+static ssize_t hiddev_write(struct file * file, const char __user * buffer, size_t count, loff_t *ppos)
+{
+	return -EINVAL;
+}
+
+/*
+ * "read" file op
+ */
+static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t count, loff_t *ppos)
+{
+	DEFINE_WAIT(wait);
+	struct hiddev_list *list = file->private_data;
+	int event_size;
+	int retval;
+
+	event_size = ((list->flags & HIDDEV_FLAG_UREF) != 0) ?
+		sizeof(struct hiddev_usage_ref) : sizeof(struct hiddev_event);
+
+	if (count < event_size)
+		return 0;
+
+	/* lock against other threads */
+	retval = mutex_lock_interruptible(&list->thread_lock);
+	if (retval)
+		return -ERESTARTSYS;
+
+	while (retval == 0) {
+		if (list->head == list->tail) {
+			prepare_to_wait(&list->hiddev->wait, &wait, TASK_INTERRUPTIBLE);
+
+			while (list->head == list->tail) {
+				if (signal_pending(current)) {
+					retval = -ERESTARTSYS;
+					break;
+				}
+				if (!list->hiddev->exist) {
+					retval = -EIO;
+					break;
+				}
+				if (file->f_flags & O_NONBLOCK) {
+					retval = -EAGAIN;
+					break;
+				}
+
+				/* let O_NONBLOCK tasks run */
+				mutex_unlock(&list->thread_lock);
+				schedule();
+				if (mutex_lock_interruptible(&list->thread_lock)) {
+					finish_wait(&list->hiddev->wait, &wait);
+					return -EINTR;
+				}
+				set_current_state(TASK_INTERRUPTIBLE);
+			}
+			finish_wait(&list->hiddev->wait, &wait);
+
+		}
+
+		if (retval) {
+			mutex_unlock(&list->thread_lock);
+			return retval;
+		}
+
+
+		while (list->head != list->tail &&
+		       retval + event_size <= count) {
+			if ((list->flags & HIDDEV_FLAG_UREF) == 0) {
+				if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE) {
+					struct hiddev_event event;
+
+					event.hid = list->buffer[list->tail].usage_code;
+					event.value = list->buffer[list->tail].value;
+					if (copy_to_user(buffer + retval, &event, sizeof(struct hiddev_event))) {
+						mutex_unlock(&list->thread_lock);
+						return -EFAULT;
+					}
+					retval += sizeof(struct hiddev_event);
+				}
+			} else {
+				if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE ||
+				    (list->flags & HIDDEV_FLAG_REPORT) != 0) {
+
+					if (copy_to_user(buffer + retval, list->buffer + list->tail, sizeof(struct hiddev_usage_ref))) {
+						mutex_unlock(&list->thread_lock);
+						return -EFAULT;
+					}
+					retval += sizeof(struct hiddev_usage_ref);
+				}
+			}
+			list->tail = (list->tail + 1) & (HIDDEV_BUFFER_SIZE - 1);
+		}
+
+	}
+	mutex_unlock(&list->thread_lock);
+
+	return retval;
+}
+
+/*
+ * "poll" file op
+ * No kernel lock - fine
+ */
+static unsigned int hiddev_poll(struct file *file, poll_table *wait)
+{
+	struct hiddev_list *list = file->private_data;
+
+	poll_wait(file, &list->hiddev->wait, wait);
+	if (list->head != list->tail)
+		return POLLIN | POLLRDNORM;
+	if (!list->hiddev->exist)
+		return POLLERR | POLLHUP;
+	return 0;
+}
+
+/*
+ * "ioctl" file op
+ */
+static noinline int hiddev_ioctl_usage(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
+{
+	struct hid_device *hid = hiddev->hid;
+	struct hiddev_report_info rinfo;
+	struct hiddev_usage_ref_multi *uref_multi = NULL;
+	struct hiddev_usage_ref *uref;
+	struct hid_report *report;
+	struct hid_field *field;
+	int i;
+
+	uref_multi = kmalloc(sizeof(struct hiddev_usage_ref_multi), GFP_KERNEL);
+	if (!uref_multi)
+		return -ENOMEM;
+	uref = &uref_multi->uref;
+	if (cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) {
+		if (copy_from_user(uref_multi, user_arg,
+				   sizeof(*uref_multi)))
+			goto fault;
+	} else {
+		if (copy_from_user(uref, user_arg, sizeof(*uref)))
+			goto fault;
+	}
+
+	switch (cmd) {
+	case HIDIOCGUCODE:
+		rinfo.report_type = uref->report_type;
+		rinfo.report_id = uref->report_id;
+		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
+			goto inval;
+
+		if (uref->field_index >= report->maxfield)
+			goto inval;
+
+		field = report->field[uref->field_index];
+		if (uref->usage_index >= field->maxusage)
+			goto inval;
+
+		uref->usage_code = field->usage[uref->usage_index].hid;
+
+		if (copy_to_user(user_arg, uref, sizeof(*uref)))
+			goto fault;
+
+		goto goodreturn;
+
+	default:
+		if (cmd != HIDIOCGUSAGE &&
+		    cmd != HIDIOCGUSAGES &&
+		    uref->report_type == HID_REPORT_TYPE_INPUT)
+			goto inval;
+
+		if (uref->report_id == HID_REPORT_ID_UNKNOWN) {
+			field = hiddev_lookup_usage(hid, uref);
+			if (field == NULL)
+				goto inval;
+		} else {
+			rinfo.report_type = uref->report_type;
+			rinfo.report_id = uref->report_id;
+			if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
+				goto inval;
+
+			if (uref->field_index >= report->maxfield)
+				goto inval;
+
+			field = report->field[uref->field_index];
+
+			if (cmd == HIDIOCGCOLLECTIONINDEX) {
+				if (uref->usage_index >= field->maxusage)
+					goto inval;
+			} else if (uref->usage_index >= field->report_count)
+				goto inval;
+		}
+
+		if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) &&
+		    (uref_multi->num_values > HID_MAX_MULTI_USAGES ||
+		     uref->usage_index + uref_multi->num_values > field->report_count))
+			goto inval;
+
+		switch (cmd) {
+		case HIDIOCGUSAGE:
+			uref->value = field->value[uref->usage_index];
+			if (copy_to_user(user_arg, uref, sizeof(*uref)))
+				goto fault;
+			goto goodreturn;
+
+		case HIDIOCSUSAGE:
+			field->value[uref->usage_index] = uref->value;
+			goto goodreturn;
+
+		case HIDIOCGCOLLECTIONINDEX:
+			i = field->usage[uref->usage_index].collection_index;
+			kfree(uref_multi);
+			return i;
+		case HIDIOCGUSAGES:
+			for (i = 0; i < uref_multi->num_values; i++)
+				uref_multi->values[i] =
+				    field->value[uref->usage_index + i];
+			if (copy_to_user(user_arg, uref_multi,
+					 sizeof(*uref_multi)))
+				goto fault;
+			goto goodreturn;
+		case HIDIOCSUSAGES:
+			for (i = 0; i < uref_multi->num_values; i++)
+				field->value[uref->usage_index + i] =
+				    uref_multi->values[i];
+			goto goodreturn;
+		}
+
+goodreturn:
+		kfree(uref_multi);
+		return 0;
+fault:
+		kfree(uref_multi);
+		return -EFAULT;
+inval:
+		kfree(uref_multi);
+		return -EINVAL;
+	}
+}
+
+static noinline int hiddev_ioctl_string(struct hiddev *hiddev, unsigned int cmd, void __user *user_arg)
+{
+	struct hid_device *hid = hiddev->hid;
+	struct usb_device *dev = hid_to_usb_dev(hid);
+	int idx, len;
+	char *buf;
+
+	if (get_user(idx, (int __user *)user_arg))
+		return -EFAULT;
+
+	if ((buf = kmalloc(HID_STRING_SIZE, GFP_KERNEL)) == NULL)
+		return -ENOMEM;
+
+	if ((len = usb_string(dev, idx, buf, HID_STRING_SIZE-1)) < 0) {
+		kfree(buf);
+		return -EINVAL;
+	}
+
+	if (copy_to_user(user_arg+sizeof(int), buf, len+1)) {
+		kfree(buf);
+		return -EFAULT;
+	}
+
+	kfree(buf);
+
+	return len;
+}
+
+static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct hiddev_list *list = file->private_data;
+	struct hiddev *hiddev = list->hiddev;
+	struct hid_device *hid;
+	struct hiddev_collection_info cinfo;
+	struct hiddev_report_info rinfo;
+	struct hiddev_field_info finfo;
+	struct hiddev_devinfo dinfo;
+	struct hid_report *report;
+	struct hid_field *field;
+	void __user *user_arg = (void __user *)arg;
+	int i, r = -EINVAL;
+
+	/* Called without BKL by compat methods so no BKL taken */
+
+	mutex_lock(&hiddev->existancelock);
+	if (!hiddev->exist) {
+		r = -ENODEV;
+		goto ret_unlock;
+	}
+
+	hid = hiddev->hid;
+
+	switch (cmd) {
+
+	case HIDIOCGVERSION:
+		r = put_user(HID_VERSION, (int __user *)arg) ?
+			-EFAULT : 0;
+		break;
+
+	case HIDIOCAPPLICATION:
+		if (arg >= hid->maxapplication)
+			break;
+
+		for (i = 0; i < hid->maxcollection; i++)
+			if (hid->collection[i].type ==
+			    HID_COLLECTION_APPLICATION && arg-- == 0)
+				break;
+
+		if (i < hid->maxcollection)
+			r = hid->collection[i].usage;
+		break;
+
+	case HIDIOCGDEVINFO:
+		{
+			struct usb_device *dev = hid_to_usb_dev(hid);
+			struct usbhid_device *usbhid = hid->driver_data;
+
+			memset(&dinfo, 0, sizeof(dinfo));
+
+			dinfo.bustype = BUS_USB;
+			dinfo.busnum = dev->bus->busnum;
+			dinfo.devnum = dev->devnum;
+			dinfo.ifnum = usbhid->ifnum;
+			dinfo.vendor = le16_to_cpu(dev->descriptor.idVendor);
+			dinfo.product = le16_to_cpu(dev->descriptor.idProduct);
+			dinfo.version = le16_to_cpu(dev->descriptor.bcdDevice);
+			dinfo.num_applications = hid->maxapplication;
+
+			r = copy_to_user(user_arg, &dinfo, sizeof(dinfo)) ?
+				-EFAULT : 0;
+			break;
+		}
+
+	case HIDIOCGFLAG:
+		r = put_user(list->flags, (int __user *)arg) ?
+			-EFAULT : 0;
+		break;
+
+	case HIDIOCSFLAG:
+		{
+			int newflags;
+
+			if (get_user(newflags, (int __user *)arg)) {
+				r = -EFAULT;
+				break;
+			}
+
+			if ((newflags & ~HIDDEV_FLAGS) != 0 ||
+			    ((newflags & HIDDEV_FLAG_REPORT) != 0 &&
+			     (newflags & HIDDEV_FLAG_UREF) == 0))
+				break;
+
+			list->flags = newflags;
+
+			r = 0;
+			break;
+		}
+
+	case HIDIOCGSTRING:
+		r = hiddev_ioctl_string(hiddev, cmd, user_arg);
+		break;
+
+	case HIDIOCINITREPORT:
+		usbhid_init_reports(hid);
+		r = 0;
+		break;
+
+	case HIDIOCGREPORT:
+		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo))) {
+			r = -EFAULT;
+			break;
+		}
+
+		if (rinfo.report_type == HID_REPORT_TYPE_OUTPUT)
+			break;
+
+		report = hiddev_lookup_report(hid, &rinfo);
+		if (report == NULL)
+			break;
+
+		hid_hw_request(hid, report, HID_REQ_GET_REPORT);
+		hid_hw_wait(hid);
+
+		r = 0;
+		break;
+
+	case HIDIOCSREPORT:
+		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo))) {
+			r = -EFAULT;
+			break;
+		}
+
+		if (rinfo.report_type == HID_REPORT_TYPE_INPUT)
+			break;
+
+		report = hiddev_lookup_report(hid, &rinfo);
+		if (report == NULL)
+			break;
+
+		hid_hw_request(hid, report, HID_REQ_SET_REPORT);
+		hid_hw_wait(hid);
+
+		r = 0;
+		break;
+
+	case HIDIOCGREPORTINFO:
+		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo))) {
+			r = -EFAULT;
+			break;
+		}
+
+		report = hiddev_lookup_report(hid, &rinfo);
+		if (report == NULL)
+			break;
+
+		rinfo.num_fields = report->maxfield;
+
+		r = copy_to_user(user_arg, &rinfo, sizeof(rinfo)) ?
+			-EFAULT : 0;
+		break;
+
+	case HIDIOCGFIELDINFO:
+		if (copy_from_user(&finfo, user_arg, sizeof(finfo))) {
+			r = -EFAULT;
+			break;
+		}
+
+		rinfo.report_type = finfo.report_type;
+		rinfo.report_id = finfo.report_id;
+
+		report = hiddev_lookup_report(hid, &rinfo);
+		if (report == NULL)
+			break;
+
+		if (finfo.field_index >= report->maxfield)
+			break;
+
+		field = report->field[finfo.field_index];
+		memset(&finfo, 0, sizeof(finfo));
+		finfo.report_type = rinfo.report_type;
+		finfo.report_id = rinfo.report_id;
+		finfo.field_index = field->report_count - 1;
+		finfo.maxusage = field->maxusage;
+		finfo.flags = field->flags;
+		finfo.physical = field->physical;
+		finfo.logical = field->logical;
+		finfo.application = field->application;
+		finfo.logical_minimum = field->logical_minimum;
+		finfo.logical_maximum = field->logical_maximum;
+		finfo.physical_minimum = field->physical_minimum;
+		finfo.physical_maximum = field->physical_maximum;
+		finfo.unit_exponent = field->unit_exponent;
+		finfo.unit = field->unit;
+
+		r = copy_to_user(user_arg, &finfo, sizeof(finfo)) ?
+			-EFAULT : 0;
+		break;
+
+	case HIDIOCGUCODE:
+		/* fall through */
+	case HIDIOCGUSAGE:
+	case HIDIOCSUSAGE:
+	case HIDIOCGUSAGES:
+	case HIDIOCSUSAGES:
+	case HIDIOCGCOLLECTIONINDEX:
+		r = hiddev_ioctl_usage(hiddev, cmd, user_arg);
+		break;
+
+	case HIDIOCGCOLLECTIONINFO:
+		if (copy_from_user(&cinfo, user_arg, sizeof(cinfo))) {
+			r = -EFAULT;
+			break;
+		}
+
+		if (cinfo.index >= hid->maxcollection)
+			break;
+
+		cinfo.type = hid->collection[cinfo.index].type;
+		cinfo.usage = hid->collection[cinfo.index].usage;
+		cinfo.level = hid->collection[cinfo.index].level;
+
+		r = copy_to_user(user_arg, &cinfo, sizeof(cinfo)) ?
+			-EFAULT : 0;
+		break;
+
+	default:
+		if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ)
+			break;
+
+		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGNAME(0))) {
+			int len = strlen(hid->name) + 1;
+			if (len > _IOC_SIZE(cmd))
+				 len = _IOC_SIZE(cmd);
+			r = copy_to_user(user_arg, hid->name, len) ?
+				-EFAULT : len;
+			break;
+		}
+
+		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGPHYS(0))) {
+			int len = strlen(hid->phys) + 1;
+			if (len > _IOC_SIZE(cmd))
+				len = _IOC_SIZE(cmd);
+			r = copy_to_user(user_arg, hid->phys, len) ?
+				-EFAULT : len;
+			break;
+		}
+	}
+
+ret_unlock:
+	mutex_unlock(&hiddev->existancelock);
+	return r;
+}
+
+#ifdef CONFIG_COMPAT
+static long hiddev_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	return hiddev_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static const struct file_operations hiddev_fops = {
+	.owner =	THIS_MODULE,
+	.read =		hiddev_read,
+	.write =	hiddev_write,
+	.poll =		hiddev_poll,
+	.open =		hiddev_open,
+	.release =	hiddev_release,
+	.unlocked_ioctl =	hiddev_ioctl,
+	.fasync =	hiddev_fasync,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= hiddev_compat_ioctl,
+#endif
+	.llseek		= noop_llseek,
+};
+
+static char *hiddev_devnode(struct device *dev, umode_t *mode)
+{
+	return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
+}
+
+static struct usb_class_driver hiddev_class = {
+	.name =		"hiddev%d",
+	.devnode =	hiddev_devnode,
+	.fops =		&hiddev_fops,
+	.minor_base =	HIDDEV_MINOR_BASE,
+};
+
+/*
+ * This is where hid.c calls us to connect a hid device to the hiddev driver
+ */
+int hiddev_connect(struct hid_device *hid, unsigned int force)
+{
+	struct hiddev *hiddev;
+	struct usbhid_device *usbhid = hid->driver_data;
+	int retval;
+
+	if (!force) {
+		unsigned int i;
+		for (i = 0; i < hid->maxcollection; i++)
+			if (hid->collection[i].type ==
+			    HID_COLLECTION_APPLICATION &&
+			    !IS_INPUT_APPLICATION(hid->collection[i].usage))
+				break;
+
+		if (i == hid->maxcollection)
+			return -1;
+	}
+
+	if (!(hiddev = kzalloc(sizeof(struct hiddev), GFP_KERNEL)))
+		return -1;
+
+	init_waitqueue_head(&hiddev->wait);
+	INIT_LIST_HEAD(&hiddev->list);
+	spin_lock_init(&hiddev->list_lock);
+	mutex_init(&hiddev->existancelock);
+	hid->hiddev = hiddev;
+	hiddev->hid = hid;
+	hiddev->exist = 1;
+	retval = usb_register_dev(usbhid->intf, &hiddev_class);
+	if (retval) {
+		hid_err(hid, "Not able to get a minor for this device\n");
+		hid->hiddev = NULL;
+		kfree(hiddev);
+		return -1;
+	}
+	return 0;
+}
+
+/*
+ * This is where hid.c calls us to disconnect a hiddev device from the
+ * corresponding hid device (usually because the usb device has disconnected)
+ */
+static struct usb_class_driver hiddev_class;
+void hiddev_disconnect(struct hid_device *hid)
+{
+	struct hiddev *hiddev = hid->hiddev;
+	struct usbhid_device *usbhid = hid->driver_data;
+
+	usb_deregister_dev(usbhid->intf, &hiddev_class);
+
+	mutex_lock(&hiddev->existancelock);
+	hiddev->exist = 0;
+
+	if (hiddev->open) {
+		mutex_unlock(&hiddev->existancelock);
+		usbhid_close(hiddev->hid);
+		wake_up_interruptible(&hiddev->wait);
+	} else {
+		mutex_unlock(&hiddev->existancelock);
+		kfree(hiddev);
+	}
+}