/*
 *  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>
 */

#define HIDDEV_MINOR_BASE	96
#define HIDDEV_MINORS		16
#define HIDDEV_BUFFER_SIZE	64

#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <linux/input.h>
#include <linux/usb.h>
#include "hid.h"
#include <linux/hiddev.h>

struct hiddev {
	int exist;
	int open;
	int minor;
	wait_queue_head_t wait;
	devfs_handle_t devfs;
	struct hid_device *hid;
	struct hiddev_list *list;
};

struct hiddev_list {
	struct hiddev_event buffer[HIDDEV_BUFFER_SIZE];
	int head;
	int tail;
	struct fasync_struct *fasync;
	struct hiddev *hiddev;
	struct hiddev_list *next;
};

static struct hiddev *hiddev_table[HIDDEV_MINORS];
static devfs_handle_t hiddev_devfs_handle;

/*
 * 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)
{
	struct hid_report_enum *report_enum;
	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);
	if ((rinfo->report_id & ~HID_REPORT_ID_MASK) != 0) {
		switch (rinfo->report_id & ~HID_REPORT_ID_MASK) {
		case HID_REPORT_ID_FIRST:
			list = report_enum->report_list.next;
			if (list == &report_enum->report_list) return NULL;
			rinfo->report_id = ((struct hid_report *) list)->id;
			break;

		case HID_REPORT_ID_NEXT:
			list = (struct list_head *)
				report_enum->report_id_hash[rinfo->report_id &
							   HID_REPORT_ID_MASK];
			if (list == NULL) return NULL;
			list = list->next;
			if (list == &report_enum->report_list) return NULL;
			rinfo->report_id = ((struct hid_report *) list)->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 list_head *list;
	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 = report_enum->report_list.next;
	while (list != &report_enum->report_list) {
		report = (struct hid_report *) 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;
				}
			}
		}
		list = list->next;
	}

	return NULL;
}

/*
 * 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, unsigned int usage, int value)
{
	struct hiddev *hiddev = hid->hiddev;
	struct hiddev_list *list = hiddev->list;

	while (list) {
		list->buffer[list->head].hid = usage;
		list->buffer[list->head].value = value;
		list->head = (list->head + 1) & (HIDDEV_BUFFER_SIZE - 1);

		kill_fasync(&list->fasync, SIGIO, POLL_IN);

		list = list->next;
	}

	wake_up_interruptible(&hiddev->wait);
}

/*
 * fasync file op
 */
static int hiddev_fasync(int fd, struct file *file, int on)
{
	int retval;
	struct hiddev_list *list = file->private_data;
	retval = fasync_helper(fd, file, on, &list->fasync);
	return retval < 0 ? retval : 0;
}

/*
 * De-allocate a hiddev structure
 */
static void hiddev_cleanup(struct hiddev *hiddev)
{
	devfs_unregister(hiddev->devfs);
	hiddev_table[hiddev->minor] = NULL;
	kfree(hiddev);
}

/*
 * release file op
 */
static int hiddev_release(struct inode * inode, struct file * file)
{
	struct hiddev_list *list = file->private_data;
	struct hiddev_list **listptr;

	listptr = &list->hiddev->list;
	hiddev_fasync(-1, file, 0);

	while (*listptr && (*listptr != list))
		listptr = &((*listptr)->next);
	*listptr = (*listptr)->next;

	if (!--list->hiddev->open) {
		if (list->hiddev->exist) 
			hid_close(list->hiddev->hid);
		else
			hiddev_cleanup(list->hiddev);
	}

	kfree(list);

	return 0;
}

/*
 * open file op
 */
static int hiddev_open(struct inode * inode, struct file * file) {
	struct hiddev_list *list;

	int i = minor(inode->i_rdev) - HIDDEV_MINOR_BASE;

	if (i >= HIDDEV_MINORS || !hiddev_table[i])
		return -ENODEV;

	if (!(list = kmalloc(sizeof(struct hiddev_list), GFP_KERNEL)))
		return -ENOMEM;
	memset(list, 0, sizeof(struct hiddev_list));

	list->hiddev = hiddev_table[i];
	list->next = hiddev_table[i]->list;
	hiddev_table[i]->list = list;

	file->private_data = list;

	if (!list->hiddev->open++)
		if (list->hiddev->exist)
			hid_open(hiddev_table[i]->hid);

	return 0;
}

/*
 * "write" file op
 */
static ssize_t hiddev_write(struct file * file, const char * buffer,
			    size_t count, loff_t *ppos)
{
	return -EINVAL;
}

/*
 * "read" file op
 */
static ssize_t hiddev_read(struct file * file, char * buffer, size_t count,
			   loff_t *ppos)
{
	DECLARE_WAITQUEUE(wait, current);
	struct hiddev_list *list = file->private_data;
	int retval = 0;

	if (list->head == list->tail) {

		add_wait_queue(&list->hiddev->wait, &wait);
		set_current_state(TASK_INTERRUPTIBLE);

		while (list->head == list->tail) {

			if (file->f_flags & O_NONBLOCK) {
				retval = -EAGAIN;
				break;
			}
			if (signal_pending(current)) {
				retval = -ERESTARTSYS;
				break;
			}
			if (!list->hiddev->exist) {
				retval = -EIO;
				break;
			}

			schedule();
		}

		set_current_state(TASK_RUNNING);
		remove_wait_queue(&list->hiddev->wait, &wait);
	}

	if (retval)
		return retval;

	while (list->head != list->tail && retval + sizeof(struct hiddev_event) <= count) {
		if (copy_to_user(buffer + retval, list->buffer + list->tail,
				 sizeof(struct hiddev_event))) return -EFAULT;
		list->tail = (list->tail + 1) & (HIDDEV_BUFFER_SIZE - 1);
		retval += sizeof(struct hiddev_event);
	}

	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;
}

#define GET_TIMEOUT 3
#define SET_TIMEOUT 3

/*
 * "ioctl" file op
 */
static int hiddev_ioctl(struct inode *inode, 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 = hiddev->hid;
	struct usb_device *dev = hid->dev;
	struct hiddev_report_info rinfo;
	struct hiddev_usage_ref uref;
	struct hid_report *report;
	struct hid_field *field;

	if (!hiddev->exist) return -EIO;

	switch (cmd) {

	case HIDIOCGVERSION:
		return put_user(HID_VERSION, (int *) arg);

	case HIDIOCAPPLICATION:
		if (arg < 0 || arg >= hid->maxapplication)
			return -EINVAL;
		return hid->application[arg];

	case HIDIOCGDEVINFO:
	{
		struct hiddev_devinfo dinfo;
		dinfo.bustype = BUS_USB;
		dinfo.busnum = dev->bus->busnum;
		dinfo.devnum = dev->devnum;
		dinfo.ifnum = hid->ifnum;
		dinfo.vendor = dev->descriptor.idVendor;
		dinfo.product = dev->descriptor.idProduct;
		dinfo.version = dev->descriptor.bcdDevice;
		dinfo.num_applications = hid->maxapplication;
		return copy_to_user((void *) arg, &dinfo, sizeof(dinfo));
	}

	case HIDIOCGSTRING:
		{
			int idx, len;
			char *buf;

			if (get_user(idx, (int *) 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((void *) (arg+sizeof(int)), buf, len+1)) {
				kfree(buf);
				return -EFAULT;
			}

			kfree(buf);

			return len;
		}

	case HIDIOCINITREPORT:

		hid_init_reports(hid);

		return 0;

	case HIDIOCGREPORT:
		if (copy_from_user(&rinfo, (void *) arg, sizeof(rinfo)))
			return -EFAULT;

		if (rinfo.report_type == HID_REPORT_TYPE_OUTPUT)
			return -EINVAL;

		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
			return -EINVAL;

		hid_read_report(hid, report);

		return 0;

	case HIDIOCSREPORT:
		if (copy_from_user(&rinfo, (void *) arg, sizeof(rinfo)))
			return -EFAULT;

		if (rinfo.report_type == HID_REPORT_TYPE_INPUT)
			return -EINVAL;

		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
			return -EINVAL;

		hid_write_report(hid, report);

		return 0;

	case HIDIOCGREPORTINFO:
		if (copy_from_user(&rinfo, (void *) arg, sizeof(rinfo)))
			return -EFAULT;

		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
			return -EINVAL;

		rinfo.num_fields = report->maxfield;

		return copy_to_user((void *) arg, &rinfo, sizeof(rinfo));

	case HIDIOCGFIELDINFO:
	{
		struct hiddev_field_info finfo;
		if (copy_from_user(&finfo, (void *) arg, sizeof(finfo)))
			return -EFAULT;
		rinfo.report_type = finfo.report_type;
		rinfo.report_id = finfo.report_id;
		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
			return -EINVAL;

		if (finfo.field_index >= report->maxfield)
			return -EINVAL;

		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;

		return copy_to_user((void *) arg, &finfo, sizeof(finfo));
	}

	case HIDIOCGUCODE:
		if (copy_from_user(&uref, (void *) arg, sizeof(uref)))
			return -EFAULT;

		rinfo.report_type = uref.report_type;
		rinfo.report_id = uref.report_id;
		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
			return -EINVAL;

		if (uref.field_index >= report->maxfield)
			return -EINVAL;

		field = report->field[uref.field_index];
		if (uref.usage_index >= field->maxusage)
			return -EINVAL;

		uref.usage_code = field->usage[uref.usage_index].hid;

		return copy_to_user((void *) arg, &uref, sizeof(uref));

	case HIDIOCGUSAGE:
		if (copy_from_user(&uref, (void *) arg, sizeof(uref)))
			return -EFAULT;

		if (uref.report_id == HID_REPORT_ID_UNKNOWN) {
			field = hiddev_lookup_usage(hid, &uref);
			if (field == NULL)
				return -EINVAL;
		} else {
			rinfo.report_type = uref.report_type;
			rinfo.report_id = uref.report_id;
			if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
				return -EINVAL;

			if (uref.field_index >= report->maxfield)
				return -EINVAL;

			field = report->field[uref.field_index];
			if (uref.usage_index >= field->maxusage)
				return -EINVAL;
		}

		uref.value = field->value[uref.usage_index];

		return copy_to_user((void *) arg, &uref, sizeof(uref));

	case HIDIOCSUSAGE:
		if (copy_from_user(&uref, (void *) arg, sizeof(uref)))
			return -EFAULT;

		if (uref.report_type == HID_REPORT_TYPE_INPUT)
			return -EINVAL;

		if (uref.report_id == HID_REPORT_ID_UNKNOWN) {
			field = hiddev_lookup_usage(hid, &uref);
			if (field == NULL)
				return -EINVAL;
		} else {
			rinfo.report_type = uref.report_type;
			rinfo.report_id = uref.report_id;
			if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)
				return -EINVAL;

			if (uref.field_index >= report->maxfield)
				return -EINVAL;

			field = report->field[uref.field_index];
			if (uref.usage_index >= field->maxusage)
				return -EINVAL;
		}

		field->value[uref.usage_index] = uref.value;

		return 0;

	default:

		if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ)
			return -EINVAL;

		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGNAME(0))) {
			int len;
			if (!hid->name) return 0;
			len = strlen(hid->name) + 1;
			if (len > _IOC_SIZE(cmd)) len = _IOC_SIZE(cmd);
			return copy_to_user((char *) arg, hid->name, len) ?
				-EFAULT : len;
		}
	}
	return -EINVAL;
}

static struct file_operations hiddev_fops = {
	owner:		THIS_MODULE,
	read:		hiddev_read,
	write:		hiddev_write,
	poll:		hiddev_poll,
	open:		hiddev_open,
	release:	hiddev_release,
	ioctl:		hiddev_ioctl,
	fasync:		hiddev_fasync,
};

/*
 * This is where hid.c calls us to connect a hid device to the hiddev driver
 */
int hiddev_connect(struct hid_device *hid)
{
	struct hiddev *hiddev;
	int minor, i;
	char devfs_name[16];

	for (i = 0; i < hid->maxapplication; i++)
		if (!IS_INPUT_APPLICATION(hid->application[i]))
			break;

	if (i == hid->maxapplication)
		return -1;

	for (minor = 0; minor < HIDDEV_MINORS && hiddev_table[minor]; minor++);
	if (minor == HIDDEV_MINORS) {
		printk(KERN_ERR "hiddev: no more free hiddev devices\n");
		return -1;
	}

	if (!(hiddev = kmalloc(sizeof(struct hiddev), GFP_KERNEL)))
		return -1;
	memset(hiddev, 0, sizeof(struct hiddev));

	init_waitqueue_head(&hiddev->wait);

	hiddev->minor = minor;
	hiddev_table[minor] = hiddev;

	hiddev->hid = hid;
	hiddev->exist = 1;

	sprintf(devfs_name, "hiddev%d", minor);
	hiddev->devfs = devfs_register(hiddev_devfs_handle, devfs_name,
				       DEVFS_FL_DEFAULT, USB_MAJOR,
				       minor + HIDDEV_MINOR_BASE,
				       S_IFCHR | S_IRUGO | S_IWUSR,
				       &hiddev_fops, NULL);
	hid->minor = minor;
	hid->hiddev = hiddev;

	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)
 */
void hiddev_disconnect(struct hid_device *hid)
{
	struct hiddev *hiddev = hid->hiddev;

	hiddev->exist = 0;

	if (hiddev->open) {
		hid_close(hiddev->hid);
		wake_up_interruptible(&hiddev->wait);
	} else {
		hiddev_cleanup(hiddev);
	}
}

/* Currently this driver is a USB driver.  It's not a conventional one in
 * the sense that it doesn't probe at the USB level.  Instead it waits to
 * be connected by HID through the hiddev_connect / hiddev_disconnect
 * routines.  The reason to register as a USB device is to gain part of the
 * minor number space from the USB major.
 *
 * In theory, should the HID code be generalized to more than one physical
 * medium (say, IEEE 1384), this driver will probably need to register its
 * own major number, and in doing so, no longer need to register with USB.
 * At that point the probe routine and hiddev_driver struct below will no
 * longer be useful.
 */


/* We never attach in this manner, and rely on HID to connect us.  This
 * is why there is no disconnect routine defined in the usb_driver either.
 */
static void *hiddev_usbd_probe(struct usb_device *dev, unsigned int ifnum,
			  const struct usb_device_id *hiddev_info)
{
	return NULL;
}


static /* const */ struct usb_driver hiddev_driver = {
	name:	"hiddev",
	probe:	hiddev_usbd_probe,
	fops:	&hiddev_fops,
	minor:	HIDDEV_MINOR_BASE
};

int __init hiddev_init(void)
{
	hiddev_devfs_handle =
		devfs_mk_dir(devfs_find_handle(NULL, "usb", 0, 0, 0, 0), "hid", NULL);
	usb_register(&hiddev_driver);
	return 0;
}

void __exit hiddev_exit(void)
{
	devfs_unregister(hiddev_devfs_handle);
	usb_deregister(&hiddev_driver);
}
