CoCalc -- Rapoo__M50-Plus-Silent.bpf.c

GitHub Repository: torvalds/linux
Path: blob/master/drivers/hid/bpf/progs/Rapoo__M50-Plus-Silent.bpf.c
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// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2024 José Expósito
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 */
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#include "vmlinux.h"
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#include "hid_bpf.h"
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#include "hid_bpf_helpers.h"
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#include <bpf/bpf_tracing.h>
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#define VID_RAPOO	0x24AE
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#define PID_M50		0x2015
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#define RDESC_SIZE	186
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HID_BPF_CONFIG(
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	HID_DEVICE(BUS_USB, HID_GROUP_GENERIC, VID_RAPOO, PID_M50)
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);
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/*
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 * The Rapoo M50 Plus Silent mouse has 2 side buttons in addition to the left,
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 * right and middle buttons. However, its original HID descriptor has a Usage
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 * Maximum of 3, preventing the side buttons to work. This HID-BPF driver
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 * changes that usage to 5.
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 *
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 * For reference, this is the original report descriptor:
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 *
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 * 0x05, 0x01,       // Usage Page (Generic Desktop)        0
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 * 0x09, 0x02,       // Usage (Mouse)                       2
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 * 0xa1, 0x01,       // Collection (Application)            4
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 * 0x85, 0x01,       //  Report ID (1)                      6
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 * 0x09, 0x01,       //  Usage (Pointer)                    8
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 * 0xa1, 0x00,       //  Collection (Physical)              10
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 * 0x05, 0x09,       //   Usage Page (Button)               12
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 * 0x19, 0x01,       //   Usage Minimum (1)                 14
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 * 0x29, 0x03,       //   Usage Maximum (3)                 16 <- change to 0x05
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 * 0x15, 0x00,       //   Logical Minimum (0)               18
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 * 0x25, 0x01,       //   Logical Maximum (1)               20
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 * 0x75, 0x01,       //   Report Size (1)                   22
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 * 0x95, 0x05,       //   Report Count (5)                  24
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 * 0x81, 0x02,       //   Input (Data,Var,Abs)              26
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 * 0x75, 0x03,       //   Report Size (3)                   28
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 * 0x95, 0x01,       //   Report Count (1)                  30
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 * 0x81, 0x01,       //   Input (Cnst,Arr,Abs)              32
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 * 0x05, 0x01,       //   Usage Page (Generic Desktop)      34
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 * 0x09, 0x30,       //   Usage (X)                         36
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 * 0x09, 0x31,       //   Usage (Y)                         38
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 * 0x16, 0x01, 0x80, //   Logical Minimum (-32767)          40
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 * 0x26, 0xff, 0x7f, //   Logical Maximum (32767)           43
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 * 0x75, 0x10,       //   Report Size (16)                  46
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 * 0x95, 0x02,       //   Report Count (2)                  48
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 * 0x81, 0x06,       //   Input (Data,Var,Rel)              50
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 * 0x09, 0x38,       //   Usage (Wheel)                     52
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 * 0x15, 0x81,       //   Logical Minimum (-127)            54
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 * 0x25, 0x7f,       //   Logical Maximum (127)             56
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 * 0x75, 0x08,       //   Report Size (8)                   58
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 * 0x95, 0x01,       //   Report Count (1)                  60
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 * 0x81, 0x06,       //   Input (Data,Var,Rel)              62
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 * 0xc0,             //  End Collection                     64
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 * 0xc0,             // End Collection                      65
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 * 0x05, 0x0c,       // Usage Page (Consumer Devices)       66
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 * 0x09, 0x01,       // Usage (Consumer Control)            68
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 * 0xa1, 0x01,       // Collection (Application)            70
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 * 0x85, 0x02,       //  Report ID (2)                      72
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 * 0x75, 0x10,       //  Report Size (16)                   74
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 * 0x95, 0x01,       //  Report Count (1)                   76
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 * 0x15, 0x01,       //  Logical Minimum (1)                78
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 * 0x26, 0x8c, 0x02, //  Logical Maximum (652)              80
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 * 0x19, 0x01,       //  Usage Minimum (1)                  83
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 * 0x2a, 0x8c, 0x02, //  Usage Maximum (652)                85
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 * 0x81, 0x00,       //  Input (Data,Arr,Abs)               88
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 * 0xc0,             // End Collection                      90
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 * 0x05, 0x01,       // Usage Page (Generic Desktop)        91
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 * 0x09, 0x80,       // Usage (System Control)              93
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 * 0xa1, 0x01,       // Collection (Application)            95
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 * 0x85, 0x03,       //  Report ID (3)                      97
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 * 0x09, 0x82,       //  Usage (System Sleep)               99
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 * 0x09, 0x81,       //  Usage (System Power Down)          101
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 * 0x09, 0x83,       //  Usage (System Wake Up)             103
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 * 0x15, 0x00,       //  Logical Minimum (0)                105
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 * 0x25, 0x01,       //  Logical Maximum (1)                107
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 * 0x19, 0x01,       //  Usage Minimum (1)                  109
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 * 0x29, 0x03,       //  Usage Maximum (3)                  111
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 * 0x75, 0x01,       //  Report Size (1)                    113
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 * 0x95, 0x03,       //  Report Count (3)                   115
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 * 0x81, 0x02,       //  Input (Data,Var,Abs)               117
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 * 0x95, 0x05,       //  Report Count (5)                   119
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 * 0x81, 0x01,       //  Input (Cnst,Arr,Abs)               121
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 * 0xc0,             // End Collection                      123
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 * 0x05, 0x01,       // Usage Page (Generic Desktop)        124
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 * 0x09, 0x00,       // Usage (Undefined)                   126
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 * 0xa1, 0x01,       // Collection (Application)            128
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 * 0x85, 0x05,       //  Report ID (5)                      130
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 * 0x06, 0x00, 0xff, //  Usage Page (Vendor Defined Page 1) 132
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 * 0x09, 0x01,       //  Usage (Vendor Usage 1)             135
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 * 0x15, 0x81,       //  Logical Minimum (-127)             137
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 * 0x25, 0x7f,       //  Logical Maximum (127)              139
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 * 0x75, 0x08,       //  Report Size (8)                    141
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 * 0x95, 0x07,       //  Report Count (7)                   143
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 * 0xb1, 0x02,       //  Feature (Data,Var,Abs)             145
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 * 0xc0,             // End Collection                      147
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 * 0x06, 0x00, 0xff, // Usage Page (Vendor Defined Page 1)  148
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 * 0x09, 0x0e,       // Usage (Vendor Usage 0x0e)           151
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 * 0xa1, 0x01,       // Collection (Application)            153
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 * 0x85, 0xba,       //  Report ID (186)                    155
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 * 0x95, 0x1f,       //  Report Count (31)                  157
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 * 0x75, 0x08,       //  Report Size (8)                    159
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 * 0x26, 0xff, 0x00, //  Logical Maximum (255)              161
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 * 0x15, 0x00,       //  Logical Minimum (0)                164
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 * 0x09, 0x01,       //  Usage (Vendor Usage 1)             166
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 * 0x91, 0x02,       //  Output (Data,Var,Abs)              168
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 * 0x85, 0xba,       //  Report ID (186)                    170
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 * 0x95, 0x1f,       //  Report Count (31)                  172
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 * 0x75, 0x08,       //  Report Size (8)                    174
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 * 0x26, 0xff, 0x00, //  Logical Maximum (255)              176
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 * 0x15, 0x00,       //  Logical Minimum (0)                179
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 * 0x09, 0x01,       //  Usage (Vendor Usage 1)             181
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 * 0x81, 0x02,       //  Input (Data,Var,Abs)               183
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 * 0xc0,             // End Collection                      185
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 */
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SEC(HID_BPF_RDESC_FIXUP)
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int BPF_PROG(hid_rdesc_fixup_rapoo_m50, struct hid_bpf_ctx *hctx)
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{
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	__u8 *data = hid_bpf_get_data(hctx, 0, HID_MAX_DESCRIPTOR_SIZE);
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	if (!data)
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		return 0; /* EPERM check */
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	if (data[17] == 0x03)
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		data[17] = 0x05;
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	return 0;
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}
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HID_BPF_OPS(rapoo_m50) = {
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	.hid_rdesc_fixup = (void *)hid_rdesc_fixup_rapoo_m50,
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};
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SEC("syscall")
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int probe(struct hid_bpf_probe_args *ctx)
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{
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	ctx->retval = ctx->rdesc_size != RDESC_SIZE;
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	if (ctx->retval)
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		ctx->retval = -EINVAL;
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	return 0;
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}
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char _license[] SEC("license") = "GPL";
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