drivers/usb/hid-core.c

/*
 * $Id: hid-core.c,v 1.42 2002/01/27 00:22:46 vojtech Exp $
 *
 *  Copyright (c) 1999 Andreas Gal
 *  Copyright (c) 2000-2001 Vojtech Pavlik
 *
 *  USB HID support for Linux
 */

/*
 * 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 <vojtech@ucw.cz>, or by paper mail:
 * Vojtech Pavlik, Simunkova 1594, Prague 8, 182 00 Czech Republic
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/smp_lock.h>
#include <linux/spinlock.h>
#include <asm/unaligned.h>
#include <asm/byteorder.h>
#include <linux/input.h>

#undef DEBUG
#undef DEBUG_DATA

#include <linux/usb.h>

#include "hid.h"
#ifdef CONFIG_USB_HIDDEV
#include <linux/hiddev.h>
#endif

/*
 * Version Information
 */

#define DRIVER_VERSION "v1.31"
#define DRIVER_AUTHOR "Andreas Gal, Vojtech Pavlik <vojtech@ucw.cz>"
#define DRIVER_DESC "USB HID core driver"
#define DRIVER_LICENSE "GPL"

static char *hid_types[] = {"Device", "Pointer", "Mouse", "Device", "Joystick",
				"Gamepad", "Keyboard", "Keypad", "Multi-Axis Controller"};

/*
 * Register a new report for a device.
 */

static struct hid_report *hid_register_report(struct hid_device *device, unsigned type, unsigned id)
{
	struct hid_report_enum *report_enum = device->report_enum + type;
	struct hid_report *report;

	if (report_enum->report_id_hash[id])
		return report_enum->report_id_hash[id];

	if (!(report = kmalloc(sizeof(struct hid_report), GFP_KERNEL)))
		return NULL;
	memset(report, 0, sizeof(struct hid_report));

	if (id != 0) report_enum->numbered = 1;

	report->id = id;
	report->type = type;
	report->size = 0;
	report->device = device;
	report_enum->report_id_hash[id] = report;

	list_add_tail(&report->list, &report_enum->report_list);

	return report;
}

/*
 * Register a new field for this report.
 */

static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages, unsigned values)
{
	struct hid_field *field;

	if (report->maxfield == HID_MAX_FIELDS) {
		dbg("too many fields in report");
		return NULL;
	}

	if (!(field = kmalloc(sizeof(struct hid_field) + usages * sizeof(struct hid_usage)
		+ values * sizeof(unsigned), GFP_KERNEL))) return NULL;

	memset(field, 0, sizeof(struct hid_field) + usages * sizeof(struct hid_usage)
		+ values * sizeof(unsigned));

	report->field[report->maxfield] = field;
	field->usage = (struct hid_usage *)(field + 1);
	field->value = (unsigned *)(field->usage + usages);
	field->report = report;
	field->index = report->maxfield++;

	return field;
}

/*
 * Open a collection. The type/usage is pushed on the stack.
 */

static int open_collection(struct hid_parser *parser, unsigned type)
{
	struct hid_collection *collection;
	unsigned usage;

	usage = parser->local.usage[0];

	if (type == HID_COLLECTION_APPLICATION
		&& parser->device->maxapplication < HID_MAX_APPLICATIONS)
			parser->device->application[parser->device->maxapplication++] = usage;

	if (parser->collection_stack_ptr == HID_COLLECTION_STACK_SIZE) {
		dbg("collection stack overflow");
		return -1;
	}

	collection = parser->collection_stack + parser->collection_stack_ptr++;
	collection->type = type;
	collection->usage = usage;

	return 0;
}

/*
 * Close a collection.
 */

static int close_collection(struct hid_parser *parser)
{
	if (!parser->collection_stack_ptr) {
		dbg("collection stack underflow");
		return -1;
	}
	parser->collection_stack_ptr--;
	return 0;
}

/*
 * Climb up the stack, search for the specified collection type
 * and return the usage.
 */

static unsigned hid_lookup_collection(struct hid_parser *parser, unsigned type)
{
	int n;
	for (n = parser->collection_stack_ptr - 1; n >= 0; n--)
		if (parser->collection_stack[n].type == type)
			return parser->collection_stack[n].usage;
	return 0; /* we know nothing about this usage type */
}

/*
 * Add a usage to the temporary parser table.
 */

static int hid_add_usage(struct hid_parser *parser, unsigned usage)
{
	if (parser->local.usage_index >= HID_MAX_USAGES) {
		dbg("usage index exceeded");
		return -1;
	}
	parser->local.usage[parser->local.usage_index++] = usage;
	return 0;
}

/*
 * Register a new field for this report.
 */

static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsigned flags)
{
	struct hid_report *report;
	struct hid_field *field;
	int usages;
	unsigned offset;
	int i;

	if (!(report = hid_register_report(parser->device, report_type, parser->global.report_id))) {
		dbg("hid_register_report failed");
		return -1;
	}

	if (parser->global.logical_maximum <= parser->global.logical_minimum) {
		dbg("logical range invalid %d %d", parser->global.logical_minimum, parser->global.logical_maximum);
		return -1;
	}
	usages = parser->local.usage_index;

	offset = report->size;
	report->size += parser->global.report_size * parser->global.report_count;

	if (usages == 0)
		return 0; /* ignore padding fields */

	if ((field = hid_register_field(report, usages, parser->global.report_count)) == NULL)
		return 0;

	field->physical = hid_lookup_collection(parser, HID_COLLECTION_PHYSICAL);
	field->logical = hid_lookup_collection(parser, HID_COLLECTION_LOGICAL);
	field->application = hid_lookup_collection(parser, HID_COLLECTION_APPLICATION);

	for (i = 0; i < usages; i++)
		field->usage[i].hid = parser->local.usage[i];

	field->maxusage = usages;
	field->flags = flags;
	field->report_offset = offset;
	field->report_type = report_type;
	field->report_size = parser->global.report_size;
	field->report_count = parser->global.report_count;
	field->logical_minimum = parser->global.logical_minimum;
	field->logical_maximum = parser->global.logical_maximum;
	field->physical_minimum = parser->global.physical_minimum;
	field->physical_maximum = parser->global.physical_maximum;
	field->unit_exponent = parser->global.unit_exponent;
	field->unit = parser->global.unit;

	return 0;
}

/*
 * Read data value from item.
 */

static __inline__ __u32 item_udata(struct hid_item *item)
{
	switch (item->size) {
		case 1: return item->data.u8;
		case 2: return item->data.u16;
		case 4: return item->data.u32;
	}
	return 0;
}

static __inline__ __s32 item_sdata(struct hid_item *item)
{
	switch (item->size) {
		case 1: return item->data.s8;
		case 2: return item->data.s16;
		case 4: return item->data.s32;
	}
	return 0;
}

/*
 * Process a global item.
 */

static int hid_parser_global(struct hid_parser *parser, struct hid_item *item)
{
	switch (item->tag) {

		case HID_GLOBAL_ITEM_TAG_PUSH:

			if (parser->global_stack_ptr == HID_GLOBAL_STACK_SIZE) {
				dbg("global enviroment stack overflow");
				return -1;
			}

			memcpy(parser->global_stack + parser->global_stack_ptr++,
				&parser->global, sizeof(struct hid_global));
			return 0;

		case HID_GLOBAL_ITEM_TAG_POP:

			if (!parser->global_stack_ptr) {
				dbg("global enviroment stack underflow");
				return -1;
			}

			memcpy(&parser->global, parser->global_stack + --parser->global_stack_ptr,
				sizeof(struct hid_global));
			return 0;

		case HID_GLOBAL_ITEM_TAG_USAGE_PAGE:
			parser->global.usage_page = item_udata(item);
			return 0;

		case HID_GLOBAL_ITEM_TAG_LOGICAL_MINIMUM:
			parser->global.logical_minimum = item_sdata(item);
			return 0;

		case HID_GLOBAL_ITEM_TAG_LOGICAL_MAXIMUM:
			if (parser->global.logical_minimum < 0)
				parser->global.logical_maximum = item_sdata(item);
			else
				parser->global.logical_maximum = item_udata(item);
			return 0;

		case HID_GLOBAL_ITEM_TAG_PHYSICAL_MINIMUM:
			parser->global.physical_minimum = item_sdata(item);
			return 0;

		case HID_GLOBAL_ITEM_TAG_PHYSICAL_MAXIMUM:
			if (parser->global.physical_minimum < 0)
				parser->global.physical_maximum = item_sdata(item);
			else
				parser->global.physical_maximum = item_udata(item);
			return 0;

		case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT:
			parser->global.unit_exponent = item_sdata(item);
			return 0;

		case HID_GLOBAL_ITEM_TAG_UNIT:
			parser->global.unit = item_udata(item);
			return 0;

		case HID_GLOBAL_ITEM_TAG_REPORT_SIZE:
			if ((parser->global.report_size = item_udata(item)) > 32) {
				dbg("invalid report_size %d", parser->global.report_size);
				return -1;
			}
			return 0;

		case HID_GLOBAL_ITEM_TAG_REPORT_COUNT:
			if ((parser->global.report_count = item_udata(item)) > HID_MAX_USAGES) {
				dbg("invalid report_count %d", parser->global.report_count);
				return -1;
			}
			return 0;

		case HID_GLOBAL_ITEM_TAG_REPORT_ID:
			if ((parser->global.report_id = item_udata(item)) == 0) {
				dbg("report_id 0 is invalid");
				return -1;
			}
			return 0;

		default:
			dbg("unknown global tag 0x%x", item->tag);
			return -1;
	}
}

/*
 * Process a local item.
 */

static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
{
	__u32 data;
	unsigned n;

	if (item->size == 0) {
		dbg("item data expected for local item");
		return -1;
	}

	data = item_udata(item);

	switch (item->tag) {

		case HID_LOCAL_ITEM_TAG_DELIMITER:

			if (data) {
				/*
				 * We treat items before the first delimiter
				 * as global to all usage sets (branch 0).
				 * In the moment we process only these global
				 * items and the first delimiter set.
				 */
				if (parser->local.delimiter_depth != 0) {
					dbg("nested delimiters");
					return -1;
				}
				parser->local.delimiter_depth++;
				parser->local.delimiter_branch++;
			} else {
				if (parser->local.delimiter_depth < 1) {
					dbg("bogus close delimiter");
					return -1;
				}
				parser->local.delimiter_depth--;
			}
			return 1;

		case HID_LOCAL_ITEM_TAG_USAGE:

			if (parser->local.delimiter_branch > 1) {
				dbg("alternative usage ignored");
				return 0;
			}

			if (item->size <= 2)
				data = (parser->global.usage_page << 16) + data;

			return hid_add_usage(parser, data);

		case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:

			if (parser->local.delimiter_branch > 1) {
				dbg("alternative usage ignored");
				return 0;
			}

			if (item->size <= 2)
				data = (parser->global.usage_page << 16) + data;

			parser->local.usage_minimum = data;
			return 0;

		case HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM:

			if (parser->local.delimiter_branch > 1) {
				dbg("alternative usage ignored");
				return 0;
			}

			if (item->size <= 2)
				data = (parser->global.usage_page << 16) + data;

			for (n = parser->local.usage_minimum; n <= data; n++)
				if (hid_add_usage(parser, n)) {
					dbg("hid_add_usage failed\n");
					return -1;
				}
			return 0;

		default:

			dbg("unknown local item tag 0x%x", item->tag);
			return 0;
	}
	return 0;
}

/*
 * Process a main item.
 */

static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
{
	__u32 data;
	int ret;

	data = item_udata(item);

	switch (item->tag) {
		case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
			ret = open_collection(parser, data & 3);
			break;
		case HID_MAIN_ITEM_TAG_END_COLLECTION:
			ret = close_collection(parser);
			break;
		case HID_MAIN_ITEM_TAG_INPUT:
			ret = hid_add_field(parser, HID_INPUT_REPORT, data);
			break;
		case HID_MAIN_ITEM_TAG_OUTPUT:
			ret = hid_add_field(parser, HID_OUTPUT_REPORT, data);
			break;
		case HID_MAIN_ITEM_TAG_FEATURE:
			ret = hid_add_field(parser, HID_FEATURE_REPORT, data);
			break;
		default:
			dbg("unknown main item tag 0x%x", item->tag);
			ret = 0;
	}

	memset(&parser->local, 0, sizeof(parser->local));	/* Reset the local parser environment */

	return ret;
}

/*
 * Process a reserved item.
 */

static int hid_parser_reserved(struct hid_parser *parser, struct hid_item *item)
{
	dbg("reserved item type, tag 0x%x", item->tag);
	return 0;
}

/*
 * Free a report and all registered fields. The field->usage and
 * field->value table's are allocated behind the field, so we need
 * only to free(field) itself.
 */

static void hid_free_report(struct hid_report *report)
{
	unsigned n;

	for (n = 0; n < report->maxfield; n++)
		kfree(report->field[n]);
	kfree(report);
}

/*
 * Free a device structure, all reports, and all fields.
 */

static void hid_free_device(struct hid_device *device)
{
	unsigned i,j;

	for (i = 0; i < HID_REPORT_TYPES; i++) {
		struct hid_report_enum *report_enum = device->report_enum + i;

		for (j = 0; j < 256; j++) {
			struct hid_report *report = report_enum->report_id_hash[j];
			if (report) hid_free_report(report);
		}
	}

	if (device->rdesc) kfree(device->rdesc);
}

/*
 * Fetch a report description item from the data stream. We support long
 * items, though they are not used yet.
 */

static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
{
	u8 b;

	if ((end - start) <= 0)
		return NULL;

	b = *start++;

	item->type = (b >> 2) & 3;
	item->tag  = (b >> 4) & 15;

	if (item->tag == HID_ITEM_TAG_LONG) {

		item->format = HID_ITEM_FORMAT_LONG;

		if ((end - start) < 2)
			return NULL;

		item->size = *start++;
		item->tag  = *start++;

		if ((end - start) < item->size) 
			return NULL;

		item->data.longdata = start;
		start += item->size;
		return start;
	} 

	item->format = HID_ITEM_FORMAT_SHORT;
	item->size = b & 3;

	switch (item->size) {

		case 0:
			return start;

		case 1:
			if ((end - start) < 1)
				return NULL;
			item->data.u8 = *start++;
			return start;

		case 2:
			if ((end - start) < 2) 
				return NULL;
			item->data.u16 = le16_to_cpu(get_unaligned(((__u16*)start)++));
			return start;

		case 3:
			item->size++;
			if ((end - start) < 4)
				return NULL;
			item->data.u32 = le32_to_cpu(get_unaligned(((__u32*)start)++));
			return start;
	}

	return NULL;
}

/*
 * Parse a report description into a hid_device structure. Reports are
 * enumerated, fields are attached to these reports.
 */

static struct hid_device *hid_parse_report(__u8 *start, unsigned size)
{
	struct hid_device *device;
	struct hid_parser *parser;
	struct hid_item item;
	__u8 *end;
	unsigned i;
	static int (*dispatch_type[])(struct hid_parser *parser,
				      struct hid_item *item) = {
		hid_parser_main,
		hid_parser_global,
		hid_parser_local,
		hid_parser_reserved
	};

	if (!(device = kmalloc(sizeof(struct hid_device), GFP_KERNEL)))
		return NULL;
	memset(device, 0, sizeof(struct hid_device));

	for (i = 0; i < HID_REPORT_TYPES; i++)
		INIT_LIST_HEAD(&device->report_enum[i].report_list);

	if (!(device->rdesc = (__u8 *)kmalloc(size, GFP_KERNEL))) {
		kfree(device);
		return NULL;
	}
	memcpy(device->rdesc, start, size);

	if (!(parser = kmalloc(sizeof(struct hid_parser), GFP_KERNEL))) {
		kfree(device->rdesc);
		kfree(device);
		return NULL;
	}
	memset(parser, 0, sizeof(struct hid_parser));
	parser->device = device;

	end = start + size;
	while ((start = fetch_item(start, end, &item)) != 0) {

		if (item.format != HID_ITEM_FORMAT_SHORT) {
			dbg("unexpected long global item");
			hid_free_device(device);
			kfree(parser);
			return NULL;
		}

		if (dispatch_type[item.type](parser, &item)) {
			dbg("item %u %u %u %u parsing failed\n",
				item.format, (unsigned)item.size, (unsigned)item.type, (unsigned)item.tag);
			hid_free_device(device);
			kfree(parser);
			return NULL;
		}

		if (start == end) {
			if (parser->collection_stack_ptr) {
				dbg("unbalanced collection at end of report description");
				hid_free_device(device);
				kfree(parser);
				return NULL;
			}
			if (parser->local.delimiter_depth) {
				dbg("unbalanced delimiter at end of report description");
				hid_free_device(device);
				kfree(parser);
				return NULL;
			}
			kfree(parser);
			return device;
		}
	}

	dbg("item fetching failed at offset %d\n", (int)(end - start));
	hid_free_device(device);
	kfree(parser);
	return NULL;
}

/*
 * Convert a signed n-bit integer to signed 32-bit integer. Common
 * cases are done through the compiler, the screwed things has to be
 * done by hand.
 */

static __inline__ __s32 snto32(__u32 value, unsigned n)
{
	switch (n) {
		case 8:  return ((__s8)value);
		case 16: return ((__s16)value);
		case 32: return ((__s32)value);
	}
	return value & (1 << (n - 1)) ? value | (-1 << n) : value;
}

/*
 * Convert a signed 32-bit integer to a signed n-bit integer.
 */

static __inline__ __u32 s32ton(__s32 value, unsigned n)
{
	__s32 a = value >> (n - 1);
	if (a && a != -1) return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
	return value & ((1 << n) - 1);
}

/*
 * Extract/implement a data field from/to a report.
 */

static __inline__ __u32 extract(__u8 *report, unsigned offset, unsigned n)
{
	report += (offset >> 5) << 2; offset &= 31;
	return (le64_to_cpu(get_unaligned((__u64*)report)) >> offset) & ((1 << n) - 1);
}

static __inline__ void implement(__u8 *report, unsigned offset, unsigned n, __u32 value)
{
	report += (offset >> 5) << 2; offset &= 31;
	put_unaligned((get_unaligned((__u64*)report)
		& cpu_to_le64(~((((__u64) 1 << n) - 1) << offset)))
		| cpu_to_le64((__u64)value << offset), (__u64*)report);
}

/*
 * Search an array for a value.
 */

static __inline__ int search(__s32 *array, __s32 value, unsigned n)
{
	while (n--) if (*array++ == value) return 0;
	return -1;
}

static void hid_process_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value)
{
	hid_dump_input(usage, value);
	if (hid->claimed & HID_CLAIMED_INPUT)
		hidinput_hid_event(hid, field, usage, value);
#ifdef CONFIG_USB_HIDDEV
	if (hid->claimed & HID_CLAIMED_HIDDEV) {
		struct hiddev_usage_ref uref;
		unsigned type = field->report_type;
		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_hid_event(hid, &uref);
	}
#endif
}

/*
 * Analyse a received field, and fetch the data from it. The field
 * content is stored for next report processing (we do differential
 * reporting to the layer).
 */

static void hid_input_field(struct hid_device *hid, struct hid_field *field, __u8 *data)
{
	unsigned n;
	unsigned count = field->report_count;
	unsigned offset = field->report_offset;
	unsigned size = field->report_size;
	__s32 min = field->logical_minimum;
	__s32 max = field->logical_maximum;
	__s32 value[count]; /* WARNING: gcc specific */

	for (n = 0; n < count; n++) {

			value[n] = min < 0 ? snto32(extract(data, offset + n * size, size), size) :
						    extract(data, offset + n * size, size);

			if (!(field->flags & HID_MAIN_ITEM_VARIABLE) /* Ignore report if ErrorRollOver */
			    && value[n] >= min && value[n] <= max
			    && field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
				return;
	}

	for (n = 0; n < count; n++) {

		if (HID_MAIN_ITEM_VARIABLE & field->flags) {

			if (field->flags & HID_MAIN_ITEM_RELATIVE) {
				if (!value[n]) continue;
			} else {
				if (value[n] == field->value[n]) continue;
			}	
			hid_process_event(hid, field, &field->usage[n], value[n]);
			continue;
		}

		if (field->value[n] >= min && field->value[n] <= max
			&& field->usage[field->value[n] - min].hid
			&& search(value, field->value[n], count))
				hid_process_event(hid, field, &field->usage[field->value[n] - min], 0);

		if (value[n] >= min && value[n] <= max
			&& field->usage[value[n] - min].hid
			&& search(field->value, value[n], count))
				hid_process_event(hid, field, &field->usage[value[n] - min], 1);
	}

	memcpy(field->value, value, count * sizeof(__s32));
}

static int hid_input_report(int type, struct urb *urb)
{
	struct hid_device *hid = urb->context;
	struct hid_report_enum *report_enum = hid->report_enum + type;
	u8 *data = urb->transfer_buffer;
	int len = urb->actual_length;
	struct hid_report *report;
	int n, size;

	if (!len) {
		dbg("empty report");
		return -1;
	}

#ifdef DEBUG_DATA
	printk(KERN_DEBUG __FILE__ ": report (size %u) (%snumbered)\n", len, report_enum->numbered ? "" : "un");
#endif

	n = 0;				/* Normally report number is 0 */
	if (report_enum->numbered) {	/* Device uses numbered reports, data[0] is report number */
		n = *data++;
		len--;
	}

#ifdef DEBUG_DATA
	{
		int i;
		printk(KERN_DEBUG __FILE__ ": report %d (size %u) = ", n, len);
		for (i = 0; i < n; i++)
			printk(" %02x", data[i]);
		printk("\n");
	}
#endif

	if (!(report = report_enum->report_id_hash[n])) {
		dbg("undefined report_id %d received", n);
		return -1;
	}

#ifdef CONFIG_USB_HIDDEV
	/* Notify listeners that a report has been received */
	if (hid->claimed & HID_CLAIMED_HIDDEV) {
		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_hid_event(hid, &uref);
	}
#endif

	size = ((report->size - 1) >> 3) + 1;

	if (len < size) {
		dbg("report %d is too short, (%d < %d)", report->id, len, size);
		return -1;
	}

	for (n = 0; n < report->maxfield; n++)
		hid_input_field(hid, report->field[n], data);

	return 0;
}

/*
 * Input interrupt completion handler.
 */

static void hid_irq_in(struct urb *urb)
{
	if (urb->status) {
		dbg("nonzero status in input irq %d", urb->status);
		return;
	}

	hid_input_report(HID_INPUT_REPORT, urb);
}

/*
 * Output the field into the report.
 */

static void hid_output_field(struct hid_field *field, __u8 *data)
{
	unsigned count = field->report_count;
	unsigned offset = field->report_offset;
	unsigned size = field->report_size;
	unsigned n;

	for (n = 0; n < count; n++) {
		if (field->logical_minimum < 0)	/* signed values */
			implement(data, offset + n * size, size, s32ton(field->value[n], size));
		 else				/* unsigned values */
			implement(data, offset + n * size, size, field->value[n]);
	}
}

/*
 * Create a report.
 */

void hid_output_report(struct hid_report *report, __u8 *data)
{
	unsigned n;
	for (n = 0; n < report->maxfield; n++)
		hid_output_field(report->field[n], data);
}

/*
 * Set a field value. The report this field belongs to has to be
 * created and transfered to the device, to set this value in the
 * device.
 */

int hid_set_field(struct hid_field *field, unsigned offset, __s32 value)
{
	unsigned size = field->report_size;

	hid_dump_input(field->usage + offset, value);

	if (offset >= field->report_count) {
		dbg("offset (%d) exceeds report_count (%d)", offset, field->report_count);
		hid_dump_field(field, 8);
		return -1;
	}
	if (field->logical_minimum < 0) {
		if (value != snto32(s32ton(value, size), size)) {
			dbg("value %d is out of range", value);
			return -1;
		}
	}
	field->value[offset] = value;
	return 0;
}

int hid_find_field(struct hid_device *hid, unsigned int type, unsigned int code, struct hid_field **field)
{
	struct hid_report_enum *report_enum = hid->report_enum + HID_OUTPUT_REPORT;
	struct list_head *list = report_enum->report_list.next;
	int i, j;

	while (list != &report_enum->report_list) {
		struct hid_report *report = (struct hid_report *) list;
		list = list->next;
		for (i = 0; i < report->maxfield; i++) {
			*field = report->field[i];
			for (j = 0; j < (*field)->maxusage; j++)
				if ((*field)->usage[j].type == type && (*field)->usage[j].code == code)
					return j;
		}
	}
	return -1;
}

/*
 * Find a report with a specified HID usage.
 */

int hid_find_report_by_usage(struct hid_device *hid, __u32 wanted_usage, struct hid_report **report, int type)
{
	struct hid_report_enum *report_enum = hid->report_enum + type;
	struct list_head *list = report_enum->report_list.next;
	int i, j;

	while (list != &report_enum->report_list) {
		*report = (struct hid_report *) list;
		list = list->next;
		for (i = 0; i < (*report)->maxfield; i++) {
			struct hid_field *field = (*report)->field[i];
			for (j = 0; j < field->maxusage; j++)
				if (field->logical == wanted_usage)
					return j;
		}
	}
	return -1;
}

int hid_find_field_in_report(struct hid_report *report, __u32 wanted_usage, struct hid_field **field)
{
	int i, j;

	for (i = 0; i < report->maxfield; i++) {
		*field = report->field[i];
		for (j = 0; j < (*field)->maxusage; j++)
			if ((*field)->usage[j].hid == wanted_usage)
				return j;
	}

	return -1;
}

static int hid_submit_out(struct hid_device *hid)
{
	struct hid_report *report;

	report = hid->out[hid->outtail];

	hid_output_report(report, hid->outbuf);
	hid->urbout->transfer_buffer_length = ((report->size - 1) >> 3) + 1;
	hid->urbout->dev = hid->dev;

	dbg("submitting out urb");

	if (usb_submit_urb(hid->urbout, GFP_ATOMIC)) {
		err("usb_submit_urb(out) failed");
		return -1;
	}

	return 0;
}

static int hid_submit_ctrl(struct hid_device *hid)
{
	struct hid_report *report;
	unsigned char dir;

	report = hid->ctrl[hid->ctrltail].report;
	dir = hid->ctrl[hid->ctrltail].dir;

	if (dir == USB_DIR_OUT)
		hid_output_report(report, hid->ctrlbuf);

	hid->urbctrl->transfer_buffer_length = ((report->size - 1) >> 3) + 1 + ((report->id > 0) && (dir != USB_DIR_OUT));
	hid->urbctrl->pipe = (dir == USB_DIR_OUT) ?  usb_sndctrlpipe(hid->dev, 0) : usb_rcvctrlpipe(hid->dev, 0);
	hid->urbctrl->dev = hid->dev;

	hid->cr.bRequestType = USB_TYPE_CLASS | USB_RECIP_INTERFACE | dir;
	hid->cr.bRequest = (dir == USB_DIR_OUT) ? HID_REQ_SET_REPORT : HID_REQ_GET_REPORT;
	hid->cr.wValue = ((report->type + 1) << 8) | report->id;
	hid->cr.wIndex = cpu_to_le16(hid->ifnum);
	hid->cr.wLength = cpu_to_le16(hid->urbctrl->transfer_buffer_length);

	dbg("submitting ctrl urb");

	if (usb_submit_urb(hid->urbctrl, GFP_ATOMIC)) {
		err("usb_submit_urb(ctrl) failed");
		return -1;
	}

	return 0;
}

/*
 * Output interrupt completion handler.
 */

static void hid_irq_out(struct urb *urb)
{
	struct hid_device *hid = urb->context;
	unsigned long flags;

	if (urb->status)
		warn("output irq status %d received", urb->status);

	spin_lock_irqsave(&hid->outlock, flags);

	hid->outtail = (hid->outtail + 1) & (HID_OUTPUT_FIFO_SIZE - 1);

	if (hid->outhead != hid->outtail) {
		hid_submit_out(hid);
		spin_unlock_irqrestore(&hid->outlock, flags);
		return;
	}

	clear_bit(HID_OUT_RUNNING, &hid->iofl);

	spin_unlock_irqrestore(&hid->outlock, flags);

	wake_up(&hid->wait);
}

/*
 * Control pipe completion handler.
 */

static void hid_ctrl(struct urb *urb)
{
	struct hid_device *hid = urb->context;
	unsigned long flags;

	if (urb->status)
		warn("ctrl urb status %d received", urb->status);

	spin_lock_irqsave(&hid->ctrllock, flags);

	if (hid->ctrl[hid->ctrltail].dir == USB_DIR_IN) 
		hid_input_report(hid->ctrl[hid->ctrltail].report->type, urb);

	hid->ctrltail = (hid->ctrltail + 1) & (HID_CONTROL_FIFO_SIZE - 1);

	if (hid->ctrlhead != hid->ctrltail) {
		hid_submit_ctrl(hid);
		spin_unlock_irqrestore(&hid->ctrllock, flags);
		return;
	}

	clear_bit(HID_CTRL_RUNNING, &hid->iofl);

	spin_unlock_irqrestore(&hid->ctrllock, flags);

	wake_up(&hid->wait);
}

void hid_submit_report(struct hid_device *hid, struct hid_report *report, unsigned char dir)
{
	int head;
	unsigned long flags;

	if ((hid->quirks & HID_QUIRK_NOGET) && dir == USB_DIR_IN)
		return;

	if (hid->urbout && dir == USB_DIR_OUT && report->type == HID_OUTPUT_REPORT) {

		spin_lock_irqsave(&hid->outlock, flags);

		if ((head = (hid->outhead + 1) & (HID_OUTPUT_FIFO_SIZE - 1)) == hid->outtail) {
			spin_unlock_irqrestore(&hid->outlock, flags);
			warn("output queue full");
			return;
		}

		hid->out[hid->outhead] = report;
		hid->outhead = head;

		if (!test_and_set_bit(HID_OUT_RUNNING, &hid->iofl))
			hid_submit_out(hid);

		spin_unlock_irqrestore(&hid->outlock, flags);
		return;
	}

	spin_lock_irqsave(&hid->ctrllock, flags);

	if ((head = (hid->ctrlhead + 1) & (HID_CONTROL_FIFO_SIZE - 1)) == hid->ctrltail) {
		spin_unlock_irqrestore(&hid->ctrllock, flags);
		warn("control queue full");
		return;
	}

	hid->ctrl[hid->ctrlhead].report = report;
	hid->ctrl[hid->ctrlhead].dir = dir;
	hid->ctrlhead = head;

	if (!test_and_set_bit(HID_CTRL_RUNNING, &hid->iofl))
		hid_submit_ctrl(hid);

	spin_unlock_irqrestore(&hid->ctrllock, flags);
}

int hid_wait_io(struct hid_device *hid)
{
	DECLARE_WAITQUEUE(wait, current);
	int timeout = 10*HZ;

	set_current_state(TASK_UNINTERRUPTIBLE);
	add_wait_queue(&hid->wait, &wait);

	while (timeout && test_bit(HID_CTRL_RUNNING, &hid->iofl) &&
			  test_bit(HID_OUT_RUNNING, &hid->iofl))
		timeout = schedule_timeout(timeout);

	set_current_state(TASK_RUNNING);
	remove_wait_queue(&hid->wait, &wait);

	if (!timeout) {
		dbg("timeout waiting for ctrl or out queue to clear");
		return -1;
	}

	return 0;
}

static int hid_get_class_descriptor(struct usb_device *dev, int ifnum,
		unsigned char type, void *buf, int size)
{
	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
		USB_REQ_GET_DESCRIPTOR, USB_RECIP_INTERFACE | USB_DIR_IN,
		(type << 8), ifnum, buf, size, HZ * USB_CTRL_GET_TIMEOUT);
}

int hid_open(struct hid_device *hid)
{
	if (hid->open++)
		return 0;

	hid->urbin->dev = hid->dev;

	if (usb_submit_urb(hid->urbin, GFP_KERNEL))
		return -EIO;

	return 0;
}

void hid_close(struct hid_device *hid)
{
	if (!--hid->open)
		usb_unlink_urb(hid->urbin);
}

/*
 * Initialize all reports
 */

void hid_init_reports(struct hid_device *hid)
{
	struct hid_report_enum *report_enum;
	struct hid_report *report;
	struct list_head *list;
	int len;

	report_enum = hid->report_enum + HID_INPUT_REPORT;
	list = report_enum->report_list.next;
	while (list != &report_enum->report_list) {
		report = (struct hid_report *) list;
		hid_submit_report(hid, report, USB_DIR_IN);
		list = list->next;
	}

	report_enum = hid->report_enum + HID_FEATURE_REPORT;
	list = report_enum->report_list.next;
	while (list != &report_enum->report_list) {
		report = (struct hid_report *) list;
		hid_submit_report(hid, report, USB_DIR_IN);
		list = list->next;
	}

	if (hid_wait_io(hid)) {
		warn("timeout initializing reports\n");
		return;
	}

	report_enum = hid->report_enum + HID_INPUT_REPORT;
	list = report_enum->report_list.next;
	while (list != &report_enum->report_list) {
		report = (struct hid_report *) list;
		len = ((report->size - 1) >> 3) + 1 + report_enum->numbered;
		if (len > hid->urbin->transfer_buffer_length)
			hid->urbin->transfer_buffer_length = len < HID_BUFFER_SIZE ? len : HID_BUFFER_SIZE;
		usb_control_msg(hid->dev, usb_sndctrlpipe(hid->dev, 0),
			0x0a, USB_TYPE_CLASS | USB_RECIP_INTERFACE, report->id,
			hid->ifnum, NULL, 0, HZ * USB_CTRL_SET_TIMEOUT);
		list = list->next;
	}
}

#define USB_VENDOR_ID_WACOM		0x056a
#define USB_DEVICE_ID_WACOM_GRAPHIRE	0x0010
#define USB_DEVICE_ID_WACOM_INTUOS	0x0020

#define USB_VENDOR_ID_GRIFFIN		0x077d
#define USB_DEVICE_ID_POWERMATE		0x0410
#define USB_DEVICE_ID_SOUNDKNOB		0x04AA

#define USB_VENDOR_ID_ATEN             0x0557  
#define USB_DEVICE_ID_ATEN_UC100KM     0x2004
#define USB_DEVICE_ID_ATEN_CS124U      0x2202
#define USB_DEVICE_ID_ATEN_2PORTKVM    0x2204

struct hid_blacklist {
	__u16 idVendor;
	__u16 idProduct;
	unsigned quirks;
} hid_blacklist[] = {
	{ USB_VENDOR_ID_WACOM, USB_DEVICE_ID_WACOM_GRAPHIRE, HID_QUIRK_IGNORE },
	{ USB_VENDOR_ID_WACOM, USB_DEVICE_ID_WACOM_INTUOS, HID_QUIRK_IGNORE },
	{ USB_VENDOR_ID_WACOM, USB_DEVICE_ID_WACOM_INTUOS + 1, HID_QUIRK_IGNORE },
	{ USB_VENDOR_ID_WACOM, USB_DEVICE_ID_WACOM_INTUOS + 2, HID_QUIRK_IGNORE },
	{ USB_VENDOR_ID_WACOM, USB_DEVICE_ID_WACOM_INTUOS + 3, HID_QUIRK_IGNORE },
	{ USB_VENDOR_ID_WACOM, USB_DEVICE_ID_WACOM_INTUOS + 4, HID_QUIRK_IGNORE },
	{ USB_VENDOR_ID_GRIFFIN, USB_DEVICE_ID_POWERMATE, HID_QUIRK_IGNORE  },
	{ USB_VENDOR_ID_GRIFFIN, USB_DEVICE_ID_SOUNDKNOB, HID_QUIRK_IGNORE  },
	{ USB_VENDOR_ID_ATEN, USB_DEVICE_ID_ATEN_UC100KM, HID_QUIRK_NOGET },
	{ USB_VENDOR_ID_ATEN, USB_DEVICE_ID_ATEN_CS124U, HID_QUIRK_NOGET },
	{ USB_VENDOR_ID_ATEN, USB_DEVICE_ID_ATEN_2PORTKVM, HID_QUIRK_NOGET },
	{ 0, 0 }
};

static struct hid_device *usb_hid_configure(struct usb_device *dev, int ifnum)
{
	struct usb_interface_descriptor *interface = dev->actconfig->interface[ifnum].altsetting + 0;
	struct hid_descriptor *hdesc;
	struct hid_device *hid;
	unsigned quirks = 0, rsize = 0;
	char *buf;
	int n;

	for (n = 0; hid_blacklist[n].idVendor; n++)
		if ((hid_blacklist[n].idVendor == dev->descriptor.idVendor) &&
			(hid_blacklist[n].idProduct == dev->descriptor.idProduct))
				quirks = hid_blacklist[n].quirks;

	if (quirks & HID_QUIRK_IGNORE)
		return NULL;

	if (usb_get_extra_descriptor(interface, HID_DT_HID, &hdesc) && ((!interface->bNumEndpoints) ||
		usb_get_extra_descriptor(&interface->endpoint[0], HID_DT_HID, &hdesc))) {
			dbg("class descriptor not present\n");
			return NULL;
	}

	for (n = 0; n < hdesc->bNumDescriptors; n++)
		if (hdesc->desc[n].bDescriptorType == HID_DT_REPORT)
			rsize = le16_to_cpu(hdesc->desc[n].wDescriptorLength);

	if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
		dbg("weird size of report descriptor (%u)", rsize);
		return NULL;
	}

	{
		__u8 rdesc[rsize];

		if ((n = hid_get_class_descriptor(dev, interface->bInterfaceNumber, HID_DT_REPORT, rdesc, rsize)) < 0) {
			dbg("reading report descriptor failed");
			return NULL;
		}

#ifdef DEBUG_DATA
		printk(KERN_DEBUG __FILE__ ": report descriptor (size %u, read %d) = ", rsize, n);
		for (n = 0; n < rsize; n++)
			printk(" %02x", (unsigned) rdesc[n]);
		printk("\n");
#endif

		if (!(hid = hid_parse_report(rdesc, rsize))) {
			dbg("parsing report descriptor failed");
			return NULL;
		}
	}

	hid->quirks = quirks;

	for (n = 0; n < interface->bNumEndpoints; n++) {

		struct usb_endpoint_descriptor *endpoint = &interface->endpoint[n];
		int pipe;

		if ((endpoint->bmAttributes & 3) != 3)		/* Not an interrupt endpoint */
			continue;

		if (endpoint->bEndpointAddress & USB_DIR_IN) {
			if (hid->urbin)
				continue;
			if (!(hid->urbin = usb_alloc_urb(0, GFP_KERNEL)))
				goto fail;
			pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress);
			FILL_INT_URB(hid->urbin, dev, pipe, hid->inbuf, 0, hid_irq_in, hid, endpoint->bInterval);
		} else {
			if (hid->urbout)
				continue;
			if (!(hid->urbout = usb_alloc_urb(0, GFP_KERNEL)))
				goto fail;
			pipe = usb_sndbulkpipe(dev, endpoint->bEndpointAddress);
			FILL_BULK_URB(hid->urbout, dev, pipe, hid->outbuf, 0, hid_irq_out, hid);
		}
	}

	if (!hid->urbin) {
		err("couldn't find an input interrupt endpoint");
		goto fail;
	}

	init_waitqueue_head(&hid->wait);
	
	hid->outlock = SPIN_LOCK_UNLOCKED;
	hid->ctrllock = SPIN_LOCK_UNLOCKED;

	hid->version = hdesc->bcdHID;
	hid->country = hdesc->bCountryCode;
	hid->dev = dev;
	hid->ifnum = interface->bInterfaceNumber;

	hid->name[0] = 0;

	if (!(buf = kmalloc(64, GFP_KERNEL)))
		goto fail;

	if (usb_string(dev, dev->descriptor.iManufacturer, buf, 64) > 0) {
		strcat(hid->name, buf);
		if (usb_string(dev, dev->descriptor.iProduct, buf, 64) > 0)
			sprintf(hid->name, "%s %s", hid->name, buf);
	} else
		sprintf(hid->name, "%04x:%04x", dev->descriptor.idVendor, dev->descriptor.idProduct);

	usb_make_path(dev, buf, 63);
	sprintf(hid->phys, "%s/input%d", buf, ifnum);

	if (usb_string(dev, dev->descriptor.iSerialNumber, hid->uniq, 64) <= 0)
		hid->uniq[0] = 0;

	kfree(buf);

	hid->urbctrl = usb_alloc_urb(0, GFP_KERNEL);
	FILL_CONTROL_URB(hid->urbctrl, dev, 0, (void*) &hid->cr, hid->ctrlbuf, 1, hid_ctrl, hid);

	return hid;

fail:

	hid_free_device(hid);
	if (hid->urbin) usb_free_urb(hid->urbin);
	if (hid->urbout) usb_free_urb(hid->urbout);
	if (hid->urbctrl) usb_free_urb(hid->urbctrl);

	return NULL;
}

static void* hid_probe(struct usb_device *dev, unsigned int ifnum,
		       const struct usb_device_id *id)
{
	struct hid_device *hid;
	char path[64];
	int i;
	char *c;

	dbg("HID probe called for ifnum %d", ifnum);

	if (!(hid = usb_hid_configure(dev, ifnum)))
		return NULL;

	hid_init_reports(hid);
	hid_dump_device(hid);

	if (!hidinput_connect(hid))
		hid->claimed |= HID_CLAIMED_INPUT;
#ifdef CONFIG_USB_HIDDEV
	if (!hiddev_connect(hid))
		hid->claimed |= HID_CLAIMED_HIDDEV;
#endif

	if (!hid->claimed) {
		hid_free_device(hid);
		return NULL;
	}

	printk(KERN_INFO);

	if (hid->claimed & HID_CLAIMED_INPUT)
		printk("input");
	if (hid->claimed == (HID_CLAIMED_INPUT | HID_CLAIMED_HIDDEV))
		printk(",");
	if (hid->claimed & HID_CLAIMED_HIDDEV)
		printk("hiddev%d", hid->minor);

	c = "Device";
	for (i = 0; i < hid->maxapplication; i++)
		if ((hid->application[i] & 0xffff) < ARRAY_SIZE(hid_types)) {
			c = hid_types[hid->application[i] & 0xffff];
			break;
		}

	usb_make_path(dev, path, 63);

	printk(": USB HID v%x.%02x %s [%s] on %s\n",
		hid->version >> 8, hid->version & 0xff, c, hid->name, path);

	return hid;
}

static void hid_disconnect(struct usb_device *dev, void *ptr)
{
	struct hid_device *hid = ptr;

	usb_unlink_urb(hid->urbin);
	usb_unlink_urb(hid->urbout);
	usb_unlink_urb(hid->urbctrl);


	if (hid->claimed & HID_CLAIMED_INPUT)
		hidinput_disconnect(hid);
#ifdef CONFIG_USB_HIDDEV
	if (hid->claimed & HID_CLAIMED_HIDDEV)
		hiddev_disconnect(hid);
#endif

	usb_free_urb(hid->urbin);
	usb_free_urb(hid->urbctrl);
	if (hid->urbout)
		usb_free_urb(hid->urbout);

	hid_free_device(hid);
}

static struct usb_device_id hid_usb_ids [] = {
	{ match_flags: USB_DEVICE_ID_MATCH_INT_CLASS,
	    bInterfaceClass: USB_INTERFACE_CLASS_HID },
	{ }						/* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, hid_usb_ids);

static struct usb_driver hid_driver = {
	name:		"hid",
	probe:		hid_probe,
	disconnect:	hid_disconnect,
	id_table:	hid_usb_ids,
};

static int __init hid_init(void)
{
#ifdef CONFIG_USB_HIDDEV
	hiddev_init();
#endif
	usb_register(&hid_driver);
	info(DRIVER_VERSION ":" DRIVER_DESC);

	return 0;
}

static void __exit hid_exit(void)
{
#ifdef CONFIG_USB_HIDDEV
	hiddev_exit();
#endif
	usb_deregister(&hid_driver);
}

module_init(hid_init);
module_exit(hid_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE(DRIVER_LICENSE);