cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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hid-speedlink.c (2116B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 *  HID driver for Speedlink Vicious and Divine Cezanne (USB mouse).
      4 *  Fixes "jumpy" cursor and removes nonexistent keyboard LEDS from
      5 *  the HID descriptor.
      6 *
      7 *  Copyright (c) 2011, 2013 Stefan Kriwanek <dev@stefankriwanek.de>
      8 */
      9
     10/*
     11 */
     12
     13#include <linux/device.h>
     14#include <linux/hid.h>
     15#include <linux/module.h>
     16
     17#include "hid-ids.h"
     18
     19static const struct hid_device_id speedlink_devices[] = {
     20	{ HID_USB_DEVICE(USB_VENDOR_ID_X_TENSIONS, USB_DEVICE_ID_SPEEDLINK_VAD_CEZANNE)},
     21	{ }
     22};
     23
     24static int speedlink_input_mapping(struct hid_device *hdev,
     25		struct hid_input *hi,
     26		struct hid_field *field, struct hid_usage *usage,
     27		unsigned long **bit, int *max)
     28{
     29	/*
     30	 * The Cezanne mouse has a second "keyboard" USB endpoint for it is
     31	 * able to map keyboard events to the button presses.
     32	 * It sends a standard keyboard report descriptor, though, whose
     33	 * LEDs we ignore.
     34	 */
     35	switch (usage->hid & HID_USAGE_PAGE) {
     36	case HID_UP_LED:
     37		return -1;
     38	}
     39	return 0;
     40}
     41
     42static int speedlink_event(struct hid_device *hdev, struct hid_field *field,
     43		struct hid_usage *usage, __s32 value)
     44{
     45	/* No other conditions due to usage_table. */
     46
     47	/* This fixes the "jumpy" cursor occuring due to invalid events sent
     48	 * by the device. Some devices only send them with value==+256, others
     49	 * don't. However, catching abs(value)>=256 is restrictive enough not
     50	 * to interfere with devices that were bug-free (has been tested).
     51	 */
     52	if (abs(value) >= 256)
     53		return 1;
     54	/* Drop useless distance 0 events (on button clicks etc.) as well */
     55	if (value == 0)
     56		return 1;
     57
     58	return 0;
     59}
     60
     61MODULE_DEVICE_TABLE(hid, speedlink_devices);
     62
     63static const struct hid_usage_id speedlink_grabbed_usages[] = {
     64	{ HID_GD_X, EV_REL, 0 },
     65	{ HID_GD_Y, EV_REL, 1 },
     66	{ HID_ANY_ID - 1, HID_ANY_ID - 1, HID_ANY_ID - 1}
     67};
     68
     69static struct hid_driver speedlink_driver = {
     70	.name = "speedlink",
     71	.id_table = speedlink_devices,
     72	.usage_table = speedlink_grabbed_usages,
     73	.input_mapping = speedlink_input_mapping,
     74	.event = speedlink_event,
     75};
     76module_hid_driver(speedlink_driver);
     77
     78MODULE_LICENSE("GPL");