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| 1 | +// SPDX-License-Identifier: GPL-2.0-only |
| 2 | +/* Copyright (c) 2024 José Expósito |
| 3 | + */ |
| 4 | + |
| 5 | +#include "vmlinux.h" |
| 6 | +#include "hid_bpf.h" |
| 7 | +#include "hid_bpf_helpers.h" |
| 8 | +#include <bpf/bpf_tracing.h> |
| 9 | + |
| 10 | +#define VID_RAPOO 0x24AE |
| 11 | +#define PID_M50 0x2015 |
| 12 | +#define RDESC_SIZE 186 |
| 13 | + |
| 14 | +HID_BPF_CONFIG( |
| 15 | + HID_DEVICE(BUS_USB, HID_GROUP_GENERIC, VID_RAPOO, PID_M50) |
| 16 | +); |
| 17 | + |
| 18 | +/* |
| 19 | + * The Rapoo M50 Plus Silent mouse has 2 side buttons in addition to the left, |
| 20 | + * right and middle buttons. However, its original HID descriptor has a Usage |
| 21 | + * Maximum of 3, preventing the side buttons to work. This HID-BPF driver |
| 22 | + * changes that usage to 5. |
| 23 | + * |
| 24 | + * For reference, this is the original report descriptor: |
| 25 | + * |
| 26 | + * 0x05, 0x01, // Usage Page (Generic Desktop) 0 |
| 27 | + * 0x09, 0x02, // Usage (Mouse) 2 |
| 28 | + * 0xa1, 0x01, // Collection (Application) 4 |
| 29 | + * 0x85, 0x01, // Report ID (1) 6 |
| 30 | + * 0x09, 0x01, // Usage (Pointer) 8 |
| 31 | + * 0xa1, 0x00, // Collection (Physical) 10 |
| 32 | + * 0x05, 0x09, // Usage Page (Button) 12 |
| 33 | + * 0x19, 0x01, // Usage Minimum (1) 14 |
| 34 | + * 0x29, 0x03, // Usage Maximum (3) 16 <- change to 0x05 |
| 35 | + * 0x15, 0x00, // Logical Minimum (0) 18 |
| 36 | + * 0x25, 0x01, // Logical Maximum (1) 20 |
| 37 | + * 0x75, 0x01, // Report Size (1) 22 |
| 38 | + * 0x95, 0x05, // Report Count (5) 24 |
| 39 | + * 0x81, 0x02, // Input (Data,Var,Abs) 26 |
| 40 | + * 0x75, 0x03, // Report Size (3) 28 |
| 41 | + * 0x95, 0x01, // Report Count (1) 30 |
| 42 | + * 0x81, 0x01, // Input (Cnst,Arr,Abs) 32 |
| 43 | + * 0x05, 0x01, // Usage Page (Generic Desktop) 34 |
| 44 | + * 0x09, 0x30, // Usage (X) 36 |
| 45 | + * 0x09, 0x31, // Usage (Y) 38 |
| 46 | + * 0x16, 0x01, 0x80, // Logical Minimum (-32767) 40 |
| 47 | + * 0x26, 0xff, 0x7f, // Logical Maximum (32767) 43 |
| 48 | + * 0x75, 0x10, // Report Size (16) 46 |
| 49 | + * 0x95, 0x02, // Report Count (2) 48 |
| 50 | + * 0x81, 0x06, // Input (Data,Var,Rel) 50 |
| 51 | + * 0x09, 0x38, // Usage (Wheel) 52 |
| 52 | + * 0x15, 0x81, // Logical Minimum (-127) 54 |
| 53 | + * 0x25, 0x7f, // Logical Maximum (127) 56 |
| 54 | + * 0x75, 0x08, // Report Size (8) 58 |
| 55 | + * 0x95, 0x01, // Report Count (1) 60 |
| 56 | + * 0x81, 0x06, // Input (Data,Var,Rel) 62 |
| 57 | + * 0xc0, // End Collection 64 |
| 58 | + * 0xc0, // End Collection 65 |
| 59 | + * 0x05, 0x0c, // Usage Page (Consumer Devices) 66 |
| 60 | + * 0x09, 0x01, // Usage (Consumer Control) 68 |
| 61 | + * 0xa1, 0x01, // Collection (Application) 70 |
| 62 | + * 0x85, 0x02, // Report ID (2) 72 |
| 63 | + * 0x75, 0x10, // Report Size (16) 74 |
| 64 | + * 0x95, 0x01, // Report Count (1) 76 |
| 65 | + * 0x15, 0x01, // Logical Minimum (1) 78 |
| 66 | + * 0x26, 0x8c, 0x02, // Logical Maximum (652) 80 |
| 67 | + * 0x19, 0x01, // Usage Minimum (1) 83 |
| 68 | + * 0x2a, 0x8c, 0x02, // Usage Maximum (652) 85 |
| 69 | + * 0x81, 0x00, // Input (Data,Arr,Abs) 88 |
| 70 | + * 0xc0, // End Collection 90 |
| 71 | + * 0x05, 0x01, // Usage Page (Generic Desktop) 91 |
| 72 | + * 0x09, 0x80, // Usage (System Control) 93 |
| 73 | + * 0xa1, 0x01, // Collection (Application) 95 |
| 74 | + * 0x85, 0x03, // Report ID (3) 97 |
| 75 | + * 0x09, 0x82, // Usage (System Sleep) 99 |
| 76 | + * 0x09, 0x81, // Usage (System Power Down) 101 |
| 77 | + * 0x09, 0x83, // Usage (System Wake Up) 103 |
| 78 | + * 0x15, 0x00, // Logical Minimum (0) 105 |
| 79 | + * 0x25, 0x01, // Logical Maximum (1) 107 |
| 80 | + * 0x19, 0x01, // Usage Minimum (1) 109 |
| 81 | + * 0x29, 0x03, // Usage Maximum (3) 111 |
| 82 | + * 0x75, 0x01, // Report Size (1) 113 |
| 83 | + * 0x95, 0x03, // Report Count (3) 115 |
| 84 | + * 0x81, 0x02, // Input (Data,Var,Abs) 117 |
| 85 | + * 0x95, 0x05, // Report Count (5) 119 |
| 86 | + * 0x81, 0x01, // Input (Cnst,Arr,Abs) 121 |
| 87 | + * 0xc0, // End Collection 123 |
| 88 | + * 0x05, 0x01, // Usage Page (Generic Desktop) 124 |
| 89 | + * 0x09, 0x00, // Usage (Undefined) 126 |
| 90 | + * 0xa1, 0x01, // Collection (Application) 128 |
| 91 | + * 0x85, 0x05, // Report ID (5) 130 |
| 92 | + * 0x06, 0x00, 0xff, // Usage Page (Vendor Defined Page 1) 132 |
| 93 | + * 0x09, 0x01, // Usage (Vendor Usage 1) 135 |
| 94 | + * 0x15, 0x81, // Logical Minimum (-127) 137 |
| 95 | + * 0x25, 0x7f, // Logical Maximum (127) 139 |
| 96 | + * 0x75, 0x08, // Report Size (8) 141 |
| 97 | + * 0x95, 0x07, // Report Count (7) 143 |
| 98 | + * 0xb1, 0x02, // Feature (Data,Var,Abs) 145 |
| 99 | + * 0xc0, // End Collection 147 |
| 100 | + * 0x06, 0x00, 0xff, // Usage Page (Vendor Defined Page 1) 148 |
| 101 | + * 0x09, 0x0e, // Usage (Vendor Usage 0x0e) 151 |
| 102 | + * 0xa1, 0x01, // Collection (Application) 153 |
| 103 | + * 0x85, 0xba, // Report ID (186) 155 |
| 104 | + * 0x95, 0x1f, // Report Count (31) 157 |
| 105 | + * 0x75, 0x08, // Report Size (8) 159 |
| 106 | + * 0x26, 0xff, 0x00, // Logical Maximum (255) 161 |
| 107 | + * 0x15, 0x00, // Logical Minimum (0) 164 |
| 108 | + * 0x09, 0x01, // Usage (Vendor Usage 1) 166 |
| 109 | + * 0x91, 0x02, // Output (Data,Var,Abs) 168 |
| 110 | + * 0x85, 0xba, // Report ID (186) 170 |
| 111 | + * 0x95, 0x1f, // Report Count (31) 172 |
| 112 | + * 0x75, 0x08, // Report Size (8) 174 |
| 113 | + * 0x26, 0xff, 0x00, // Logical Maximum (255) 176 |
| 114 | + * 0x15, 0x00, // Logical Minimum (0) 179 |
| 115 | + * 0x09, 0x01, // Usage (Vendor Usage 1) 181 |
| 116 | + * 0x81, 0x02, // Input (Data,Var,Abs) 183 |
| 117 | + * 0xc0, // End Collection 185 |
| 118 | + */ |
| 119 | + |
| 120 | +SEC(HID_BPF_RDESC_FIXUP) |
| 121 | +int BPF_PROG(hid_rdesc_fixup_rapoo_m50, struct hid_bpf_ctx *hctx) |
| 122 | +{ |
| 123 | + __u8 *data = hid_bpf_get_data(hctx, 0, HID_MAX_DESCRIPTOR_SIZE); |
| 124 | + |
| 125 | + if (!data) |
| 126 | + return 0; /* EPERM check */ |
| 127 | + |
| 128 | + if (data[17] == 0x03) |
| 129 | + data[17] = 0x05; |
| 130 | + |
| 131 | + return 0; |
| 132 | +} |
| 133 | + |
| 134 | +HID_BPF_OPS(rapoo_m50) = { |
| 135 | + .hid_rdesc_fixup = (void *)hid_rdesc_fixup_rapoo_m50, |
| 136 | +}; |
| 137 | + |
| 138 | +SEC("syscall") |
| 139 | +int probe(struct hid_bpf_probe_args *ctx) |
| 140 | +{ |
| 141 | + ctx->retval = ctx->rdesc_size != RDESC_SIZE; |
| 142 | + if (ctx->retval) |
| 143 | + ctx->retval = -EINVAL; |
| 144 | + |
| 145 | + return 0; |
| 146 | +} |
| 147 | + |
| 148 | +char _license[] SEC("license") = "GPL"; |
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