HID-usi sample adds support for writing USI pen variables. When the
sample is run, it creates a unix fifo under /tmp/usi, which can be
written with "<param> set <val>", where param is in [color,width,style],
and val is an integer value for the parameter.
Signed-off-by: Tero Kristo <tero.kristo@xxxxxxxxxxxxxxx>
---
samples/bpf/Makefile | 3 +
samples/bpf/hid_usi.h | 21 ++++
samples/bpf/hid_usi_kern.c | 225 +++++++++++++++++++++++++++++++++
samples/bpf/hid_usi_user.c | 247 +++++++++++++++++++++++++++++++++++++
4 files changed, 496 insertions(+)
create mode 100644 samples/bpf/hid_usi.h
create mode 100644 samples/bpf/hid_usi_kern.c
create mode 100644 samples/bpf/hid_usi_user.c
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 11f6f0cfab9e..6f45f6048979 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -62,6 +62,7 @@ tprogs-y += xdp_monitor
tprogs-y += hid_mouse
tprogs-y += hid_surface_dial
+tprogs-y += hid_usi
# Libbpf dependencies
LIBBPF_SRC = $(TOOLS_PATH)/lib/bpf
@@ -129,6 +130,7 @@ xdp_redirect-objs := xdp_redirect_user.o $(XDP_SAMPLE)
xdp_monitor-objs := xdp_monitor_user.o $(XDP_SAMPLE)
hid_mouse-objs := hid_mouse_user.o
hid_surface_dial-objs := hid_surface_dial_user.o
+hid_usi-objs := hid_usi_user.o
# Tell kbuild to always build the programs
always-y := $(tprogs-y)
@@ -188,6 +190,7 @@ always-y += hbm_edt_kern.o
always-y += xdpsock_kern.o
always-y += hid_mouse_kern.o
always-y += hid_surface_dial_kern.o
+always-y += hid_usi_kern.o
ifeq ($(ARCH), arm)
# Strip all except -D__LINUX_ARM_ARCH__ option needed to handle linux
diff --git a/samples/bpf/hid_usi.h b/samples/bpf/hid_usi.h
new file mode 100644
index 000000000000..90803375d9c1
--- /dev/null
+++ b/samples/bpf/hid_usi.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright(c) 2021 Intel Corporation.
+ */
+
+#ifndef HID_USI_H_
+#define HID_USI_H_
+
+#include <linux/bits.h>
+
+enum {
+ USI_PEN_ID = 0,
+ USI_PEN_IN_RANGE,
+ USI_PEN_TOUCHING,
+ USI_PEN_COLOR,
+ USI_PEN_LINE_WIDTH,
+ USI_PEN_LINE_STYLE,
+ USI_NUM_PARAMS
+};
+
+#endif /* HID_USI_H */
diff --git a/samples/bpf/hid_usi_kern.c b/samples/bpf/hid_usi_kern.c
new file mode 100644
index 000000000000..8b3c300f7bb2
--- /dev/null
+++ b/samples/bpf/hid_usi_kern.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2021 Intel Corporation. */
+#include <linux/version.h>
+#include <uapi/linux/bpf.h>
+#include <uapi/linux/hid.h>
+#include <uapi/linux/bpf_hid.h>
+#include <bpf/bpf_helpers.h>
+
+#include "hid_usi.h"
+
+static const char param_names[USI_NUM_PARAMS][6] = {
+ "id",
+ "flags",
+ "color",
+ "width",
+ "style",
+};
+
+struct {
+ __uint(type, BPF_MAP_TYPE_RINGBUF);
+ __uint(max_entries, 4096);
+} ringbuf SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __type(key, int);
+ __type(value, int);
+ __uint(max_entries, USI_NUM_PARAMS);
+} cache SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __type(key, int);
+ __type(value, int);
+ __uint(max_entries, USI_NUM_PARAMS);
+} wr_cache SEC(".maps");
+
+struct rep_data {
+ int offset;
+ int size;
+ int idx;
+};
+
+static struct rep_data inputs[USI_NUM_PARAMS];
+static struct rep_data features[USI_NUM_PARAMS];
+
+SEC("hid/raw_event")
+int hid_raw_event(struct hid_bpf_ctx *ctx)
+{
+ u32 i;
+ u32 tmp;
+ int val;
+ int *wrc, *c;
+ u8 *buf;
+ u32 flags = 0;
+ int offset;
+ int size;
+ int in_range;
+ int touching;
+ bool cache_valid;
+
+ if (ctx->event.data[0] != inputs[USI_PEN_IN_RANGE].idx)
+ return 0;
+
+ in_range = bpf_hid_get_data(ctx, inputs[USI_PEN_IN_RANGE].offset,
+ inputs[USI_PEN_IN_RANGE].size);
+ touching = bpf_hid_get_data(ctx, inputs[USI_PEN_TOUCHING].offset,
+ inputs[USI_PEN_TOUCHING].size);
+
+ bpf_printk("flags: in_range=%d, touching=%d", in_range, touching);
+
+ if (!touching && cache_valid) {
+ for (i = USI_PEN_COLOR; i < USI_NUM_PARAMS; i++) {
+ val = 0;
+
+ /*
+ * Make a local copy of i so that we can get a
+ * pointer reference to it. i itself must remain
+ * inside a register so that BPF verifier can
+ * calculate its value properly.
+ */
+ tmp = i;
+ bpf_map_update_elem(&wr_cache, &tmp, &val, 0);
+ bpf_map_update_elem(&cache, &tmp, &val, 0);
+ }
+ cache_valid = false;
+ }
+
+ if (!touching)
+ return 0;
+
+ for (i = USI_PEN_COLOR; i < USI_NUM_PARAMS; i++) {
+ offset = inputs[i].offset;
+ size = inputs[i].size;
+ val = bpf_hid_get_data(ctx, offset, size);
+
+ /*
+ * Again, make a local copy of i which we can refer via a
+ * pointer to satisfy BPF verifier.
+ */
+ tmp = i;
+
+ wrc = bpf_map_lookup_elem(&wr_cache, &tmp);
+ c = bpf_map_lookup_elem(&cache, &tmp);
+ if (!wrc || !c)
+ continue;
+
+ bpf_printk("raw[%d]: %s = %02x", i, param_names[i], val);
+ bpf_printk(" (c=%02x, wr=%02x)", *c, *wrc);
+
+ if (*wrc != *c) {
+ val = *wrc;
+
+ buf = bpf_ringbuf_reserve(&ringbuf, 16, 0);
+ if (!buf)
+ continue;
+
+ buf[0] = features[i].idx;
+ buf[1] = 1;
+ buf[2] = val;
+
+ bpf_hid_raw_request(ctx, buf, 3,
+ HID_FEATURE_REPORT,
+ HID_REQ_SET_REPORT);
+
+ bpf_ringbuf_discard(buf, 0);
+ }
+
+ if (val != *c && !cache_valid) {
+ bpf_map_update_elem(&cache, &tmp, &val, 0);
+ bpf_map_update_elem(&wr_cache, &tmp, &val, 0);
+ cache_valid = true;
+ } else {
+ bpf_hid_set_data(ctx, offset, size, *c);
+ }
+ }
+
+ return 0;
+}
+
+SEC("hid/event")
+int set_haptic(struct hid_bpf_ctx *ctx)
+{
+ return 0;
+}
+
+static void process_tag(struct hid_bpf_ctx *ctx, struct rep_data *data,
+ struct hid_bpf_parser *parser, u64 *idx)
+{
+ u32 i;
+ int id;
+ u32 offset;
+
+ for (i = 0; i < parser->local.usage_index && i < 16; i++) {
+ offset = parser->report.current_offset +
+ i * parser->global.report_size;
+
+ switch (parser->local.usage[i]) {
+ case HID_DG_PEN_COLOR:
+ id = USI_PEN_COLOR;
+ break;
+ case HID_DG_PEN_LINE_WIDTH:
+ id = USI_PEN_LINE_WIDTH;
+ break;
+ case HID_DG_PEN_LINE_STYLE_INK:
+ id = USI_PEN_LINE_STYLE;
+ break;
+ case HID_DG_INRANGE:
+ if (parser->local.usage_index == 1)
+ continue;
+
+ id = USI_PEN_IN_RANGE;
+ break;
+ case HID_DG_TIPSWITCH:
+ if (parser->local.usage_index == 1)
+ continue;
+
+ id = USI_PEN_TOUCHING;
+ break;
+ default:
+ continue;
+ }
+
+ data[id].offset = offset + 8;
+ data[id].size = parser->global.report_size;
+ data[id].idx = parser->report.id;
+
+ bpf_printk("parsed id=%d, offset=%d, idx=%d",
+ id, data[id].offset, data[id].idx);
+ }
+}
+
+static u64 process_hid_rdesc_item(struct hid_bpf_ctx *ctx,
+ struct hid_bpf_parser *parser, u64 *idx,
+ void *data)
+{
+ struct hid_bpf_item *item = &parser->item;
+
+ switch (item->type) {
+ case HID_ITEM_TYPE_MAIN:
+ if (item->tag == HID_MAIN_ITEM_TAG_INPUT)
+ process_tag(ctx, inputs, parser, idx);
+ if (item->tag == HID_MAIN_ITEM_TAG_FEATURE)
+ process_tag(ctx, features, parser, idx);
+ }
+
+ return 0;
+}
+
+SEC("hid/rdesc_fixup")
+int hid_rdesc_fixup(struct hid_bpf_ctx *ctx)
+{
+ int ret;
+
+ if (ctx->type != HID_BPF_RDESC_FIXUP)
+ return 0;
+
+ ret = bpf_hid_foreach_rdesc_item(ctx, process_hid_rdesc_item, (void *)0, 0);
+ bpf_printk("ret: %d", ret);
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
+u32 _version SEC("version") = LINUX_VERSION_CODE;
diff --git a/samples/bpf/hid_usi_user.c b/samples/bpf/hid_usi_user.c
new file mode 100644
index 000000000000..b05a3f768835
--- /dev/null
+++ b/samples/bpf/hid_usi_user.c
@@ -0,0 +1,247 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021, Intel Corporation
+ */
+#include <linux/bpf.h>
+#include <linux/if_link.h>
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <libgen.h>
+#include <sys/resource.h>
+#include <getopt.h>
+
+#include "bpf_util.h"
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#include <sys/stat.h>
+
+#include "hid_usi.h"
+
+static char *sysfs_path;
+static char *fifoname = "/tmp/usi";
+static int sysfs_fd;
+static int fifo_fd;
+static int prog_count;
+static int cache, wr_cache;
+
+static const struct option long_options[] = {
+ { "help", no_argument, NULL, 'h' },
+ { "fifo", required_argument, NULL, 'f' },
+};
+
+struct prog {
+ int fd;
+ enum bpf_attach_type type;
+};
+
+static struct prog progs[10];
+
+static void int_exit(int sig)
+{
+ int ret;
+
+ for (prog_count--; prog_count >= 0 ; prog_count--) {
+ ret = bpf_prog_detach2(progs[prog_count].fd, sysfs_fd, progs[prog_count].type);
+ if (ret)
+ fprintf(stderr, "bpf_prog_detach2: returned %m\n");
+ }
+
+ close(sysfs_fd);
+ close(fifo_fd);
+ remove(fifoname);
+ exit(0);
+}
+
+static void usage(const char *prog)
+{
+ fprintf(stderr,
+ "usage: %s [-f <fifoname>] /dev/HIDRAW\n\n",
+ prog);
+}
+
+static int param_to_idx(const char *param)
+{
+ if (!strcmp(param, "color"))
+ return USI_PEN_COLOR;
+ if (!strcmp(param, "width"))
+ return USI_PEN_LINE_WIDTH;
+ if (!strcmp(param, "style"))
+ return USI_PEN_LINE_STYLE;
+
+ return -EINVAL;
+}
+
+static int write_value(const char *param, int value)
+{
+ int err;
+ int idx = param_to_idx(param);
+
+ printf("%s: param=%s (%d), value=%d\n", __func__, param, idx, value);
+ err = bpf_map_update_elem(wr_cache, &idx, &value, BPF_ANY);
+ if (err)
+ printf("Update failed for %d, err=%d\n", idx, err);
+
+ return 0;
+}
+
+static int read_value(const char *param)
+{
+ int value;
+ int idx = param_to_idx(param);
+
+ printf("%s: param=%s (%d)\n", __func__, param, idx);
+
+ if (bpf_map_lookup_elem(cache, &idx, &value))
+ printf("Value missing for %d\n", idx);
+ else
+ printf("Value for %d = %d\n", idx, value);
+
+ return 0;
+}
+
+static int attach_progs(int argc, char **argv)
+{
+ char filename[256];
+ struct bpf_prog_info info = {};
+ __u32 info_len = sizeof(info);
+ struct bpf_object *obj;
+ struct bpf_program *prog;
+ int err = 0;
+ char buf[BUFSIZ];
+ char param[16];
+ char op[8];
+ int value;
+ int m, n;
+
+ snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+ obj = bpf_object__open_file(filename, NULL);
+ err = libbpf_get_error(obj);
+ if (err) {
+ fprintf(stderr, "ERROR: opening BPF object file failed\n");
+ obj = NULL;
+ err = 1;
+ goto cleanup;
+ }
+
+ /* load BPF program */
+ err = bpf_object__load(obj);
+ if (err) {
+ fprintf(stderr, "ERROR: loading BPF object file failed\n");
+ goto cleanup;
+ }
+
+ sysfs_fd = open(sysfs_path, O_RDONLY);
+
+ bpf_object__for_each_program(prog, obj) {
+ progs[prog_count].fd = bpf_program__fd(prog);
+ progs[prog_count].type = bpf_program__get_expected_attach_type(prog);
+
+ err = bpf_prog_attach(progs[prog_count].fd,
+ sysfs_fd,
+ progs[prog_count].type,
+ 0);
+ if (err) {
+ fprintf(stderr, "bpf_prog_attach: err=%m\n");
+ progs[prog_count].fd = 0;
+ goto cleanup;
+ }
+ printf("attached BPF program with FD=%d, type=%d\n",
+ progs[prog_count].fd, progs[prog_count].type);
+ prog_count++;
+ }
+
+ signal(SIGINT, int_exit);
+ signal(SIGTERM, int_exit);
+
+ err = bpf_obj_get_info_by_fd(progs[0].fd, &info, &info_len);
+ if (err) {
+ printf("can't get prog info - %s\n", strerror(errno));
+ goto cleanup;
+ }
+
+ cache = bpf_object__find_map_fd_by_name(obj, "cache");
+ if (cache < 0) {
+ printf("can't get 'cache' shared mem from object - %m\n");
+ goto cleanup;
+ }
+
+ wr_cache = bpf_object__find_map_fd_by_name(obj, "wr_cache");
+ if (wr_cache < 0) {
+ printf("can't get 'wr_cache' shared mem from object - %m\n");
+ goto cleanup;
+ }
+
+ mkfifo(fifoname, 0666);
+
+ fifo_fd = open(fifoname, O_RDWR);
+ if (fifo_fd < 0) {
+ perror("Fifo open error.\n");
+ err = fifo_fd;
+ goto cleanup;
+ }
+
+ while (1) {
+ n = read(fifo_fd, buf, BUFSIZ);
+ if (n < 0)
+ break;
+ buf[n] = 0;
+
+ printf("%s: received '%s'\n", __func__, buf);
+
+ m = sscanf(buf, "%16s %8s %d", param, op, &value);
+ if (m == 2 && strcmp(op, "get") == 0)
+ read_value(param);
+ else if (m == 3 && strcmp(op, "set") == 0)
+ write_value(param, value);
+ }
+
+ return 0;
+
+ cleanup:
+ for (prog_count--; prog_count >= 0; prog_count--) {
+ if (bpf_prog_detach2(progs[prog_count].fd, sysfs_fd, progs[prog_count].type))
+ fprintf(stderr, "bpf_prog_detach2: returned %m\n");
+ }
+
+ bpf_object__close(obj);
+ return err;
+}
+
+int main(int argc, char **argv)
+{
+ int opt;
+
+ while ((opt = getopt_long(argc, argv, "f:", long_options,
+ NULL)) != -1) {
+ switch (opt) {
+ case 'f':
+ fifoname = optarg;
+ break;
+ default:
+ usage(basename(argv[0]));
+ return 1;
+ }
+ }
+
+ if (optind == argc) {
+ usage(basename(argv[0]));
+ return 1;
+ }
+
+ sysfs_path = argv[optind];
+ if (!sysfs_path) {
+ perror("hidraw");
+ return 1;
+ }
+
+ printf("fifoname: %s\n", fifoname);
+ printf("sysfs_path: %s\n", sysfs_path);
+
+ return attach_progs(argc, argv);
+}
--
2.25.1
