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Diffstat (limited to 'samples/hid/hid_surface_dial.bpf.c')
-rw-r--r--samples/hid/hid_surface_dial.bpf.c134
1 files changed, 134 insertions, 0 deletions
diff --git a/samples/hid/hid_surface_dial.bpf.c b/samples/hid/hid_surface_dial.bpf.c
new file mode 100644
index 0000000000..1f80478c09
--- /dev/null
+++ b/samples/hid/hid_surface_dial.bpf.c
@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2022 Benjamin Tissoires
+ */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "hid_bpf_helpers.h"
+
+#define HID_UP_BUTTON 0x0009
+#define HID_GD_WHEEL 0x0038
+
+SEC("fmod_ret/hid_bpf_device_event")
+int BPF_PROG(hid_event, struct hid_bpf_ctx *hctx)
+{
+ __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 9 /* size */);
+
+ if (!data)
+ return 0; /* EPERM check */
+
+ /* Touch */
+ data[1] &= 0xfd;
+
+ /* X */
+ data[4] = 0;
+ data[5] = 0;
+
+ /* Y */
+ data[6] = 0;
+ data[7] = 0;
+
+ return 0;
+}
+
+/* 72 == 360 / 5 -> 1 report every 5 degrees */
+int resolution = 72;
+int physical = 5;
+
+struct haptic_syscall_args {
+ unsigned int hid;
+ int retval;
+};
+
+static __u8 haptic_data[8];
+
+SEC("syscall")
+int set_haptic(struct haptic_syscall_args *args)
+{
+ struct hid_bpf_ctx *ctx;
+ const size_t size = sizeof(haptic_data);
+ u16 *res;
+ int ret;
+
+ if (size > sizeof(haptic_data))
+ return -7; /* -E2BIG */
+
+ ctx = hid_bpf_allocate_context(args->hid);
+ if (!ctx)
+ return -1; /* EPERM check */
+
+ haptic_data[0] = 1; /* report ID */
+
+ ret = hid_bpf_hw_request(ctx, haptic_data, size, HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
+
+ bpf_printk("probed/remove event ret value: %d", ret);
+ bpf_printk("buf: %02x %02x %02x",
+ haptic_data[0],
+ haptic_data[1],
+ haptic_data[2]);
+ bpf_printk(" %02x %02x %02x",
+ haptic_data[3],
+ haptic_data[4],
+ haptic_data[5]);
+ bpf_printk(" %02x %02x",
+ haptic_data[6],
+ haptic_data[7]);
+
+ /* whenever resolution multiplier is not 3600, we have the fixed report descriptor */
+ res = (u16 *)&haptic_data[1];
+ if (*res != 3600) {
+// haptic_data[1] = 72; /* resolution multiplier */
+// haptic_data[2] = 0; /* resolution multiplier */
+// haptic_data[3] = 0; /* Repeat Count */
+ haptic_data[4] = 3; /* haptic Auto Trigger */
+// haptic_data[5] = 5; /* Waveform Cutoff Time */
+// haptic_data[6] = 80; /* Retrigger Period */
+// haptic_data[7] = 0; /* Retrigger Period */
+ } else {
+ haptic_data[4] = 0;
+ }
+
+ ret = hid_bpf_hw_request(ctx, haptic_data, size, HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
+
+ bpf_printk("set haptic ret value: %d -> %d", ret, haptic_data[4]);
+
+ args->retval = ret;
+
+ hid_bpf_release_context(ctx);
+
+ return 0;
+}
+
+/* Convert REL_DIAL into REL_WHEEL */
+SEC("fmod_ret/hid_bpf_rdesc_fixup")
+int BPF_PROG(hid_rdesc_fixup, struct hid_bpf_ctx *hctx)
+{
+ __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */);
+ __u16 *res, *phys;
+
+ if (!data)
+ return 0; /* EPERM check */
+
+ /* Convert TOUCH into a button */
+ data[31] = HID_UP_BUTTON;
+ data[33] = 2;
+
+ /* Convert REL_DIAL into REL_WHEEL */
+ data[45] = HID_GD_WHEEL;
+
+ /* Change Resolution Multiplier */
+ phys = (__u16 *)&data[61];
+ *phys = physical;
+ res = (__u16 *)&data[66];
+ *res = resolution;
+
+ /* Convert X,Y from Abs to Rel */
+ data[88] = 0x06;
+ data[98] = 0x06;
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
+u32 _version SEC("version") = 1;