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authorSean Young <sean@mess.org>2019-07-30 14:58:28 +0900
committerSean Young <sean@mess.org>2019-08-08 22:28:24 +0100
commit73f8f2f0acdce9f9ad91da9aa5390c5c7a6ddfd2 (patch)
tree81843410ad7837ed373aef3af1afb66a736adbb8 /utils/keytable/bpf_protocols/raw.c
parent6aa15f7447d4aeca6af1ed7ee9644a0c7e891ece (diff)
keytable: add support for keymap with raw literals
These rc keymaps look like: [[protocols]] name = 'Beon_Colour_TV' protocol = 'raw' [[protocols.raw]] keycode = 'KEY_POWER' raw = [ 1324, 842, 6697, 26400, 1324, 842, 6697 ] [[protocols.raw]] keycode = 'KEY_MUTE' raw = [ 1305, 865, 2357, 931, 3411, 26400, 1305, 865, 2357, 931, 3411 ] So the incoming IR will be literally compared against the IR given, and only if the entire array matches with no leading or trailing IR will the keycode be reported. This is analogous to lircd raw_codes support, so lircd2toml.py can also convert raw_codes lircd.conf files. This means that the vast majority of lircd files can now be converted. This feature requires loops in BPF programs so this is only supported in kernel 5.3 onwards. Signed-off-by: Sean Young <sean@mess.org>
Diffstat (limited to 'utils/keytable/bpf_protocols/raw.c')
-rw-r--r--utils/keytable/bpf_protocols/raw.c149
1 files changed, 149 insertions, 0 deletions
diff --git a/utils/keytable/bpf_protocols/raw.c b/utils/keytable/bpf_protocols/raw.c
new file mode 100644
index 00000000..a0ee78b4
--- /dev/null
+++ b/utils/keytable/bpf_protocols/raw.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Copyright (C) 2019 Sean Young <sean@mess.org>
+//
+// This decoder matches pre-defined pulse-space sequences. It does so by
+// iterating through the list There are many optimisation possible, if
+// performance is an issue.
+//
+// First of all iterating through the list of patterns is one-by-one, even
+// though after the first few pulse space sequences, most patterns will be
+// will not be a match. The bitmap datastructure could use a "next clear bit"
+// function.
+//
+// Secondly this can be transformed into a much more efficient state machine,
+// where we pre-compile the patterns much like a regex.
+
+#include <linux/lirc.h>
+#include <linux/bpf.h>
+
+#include "bpf_helpers.h"
+#include "bitmap.h"
+
+#define MAX_PATTERNS 1024
+
+struct decoder_state {
+ int pos;
+ DECLARE_BITMAP(nomatch, MAX_PATTERNS);
+};
+
+struct bpf_map_def SEC("maps") decoder_state_map = {
+ .type = BPF_MAP_TYPE_ARRAY,
+ .key_size = sizeof(unsigned int),
+ .value_size = sizeof(struct decoder_state),
+ .max_entries = 1,
+};
+
+struct raw_pattern {
+ unsigned int scancode;
+ unsigned short raw[0];
+};
+
+// ir-keytable will load the raw patterns here
+struct bpf_map_def SEC("maps") raw_map = {
+ .type = BPF_MAP_TYPE_ARRAY,
+ .key_size = sizeof(unsigned int),
+ .value_size = sizeof(struct raw_pattern), // this is not used
+ .max_entries = MAX_PATTERNS,
+};
+
+
+// These values can be overridden in the rc_keymap toml
+//
+// We abuse elf relocations. We cast the address of these variables to
+// an int, so that the compiler emits a mov immediate for the address
+// but uses it as an int. The bpf loader replaces the relocation with the
+// actual value (either overridden or taken from the data segment).
+int margin = 200;
+int rc_protocol = 68;
+// The following two values are calculated by ir-keytable
+int trail_space = 1000;
+int max_length = 1;
+
+#define BPF_PARAM(x) (int)(&(x))
+
+static inline int eq_margin(unsigned d1, unsigned d2)
+{
+ return ((d1 > (d2 - BPF_PARAM(margin))) && (d1 < (d2 + BPF_PARAM(margin))));
+}
+
+SEC("raw")
+int bpf_decoder(unsigned int *sample)
+{
+ unsigned int key = 0;
+ struct decoder_state *s = bpf_map_lookup_elem(&decoder_state_map, &key);
+ struct raw_pattern *p;
+ unsigned int i;
+
+ // Make verifier happy. Should never come to pass
+ if (!s)
+ return 0;
+
+ switch (*sample & LIRC_MODE2_MASK) {
+ case LIRC_MODE2_SPACE:
+ case LIRC_MODE2_PULSE:
+ case LIRC_MODE2_TIMEOUT:
+ break;
+ default:
+ // not a timing events
+ return 0;
+ }
+
+ int duration = LIRC_VALUE(*sample);
+ int pulse = LIRC_IS_PULSE(*sample);
+ int pos = s->pos;
+
+ if (pos < 0 || pos >= BPF_PARAM(max_length)) {
+ if (!pulse && duration >= BPF_PARAM(trail_space)) {
+ bitmap_zero(s->nomatch, MAX_PATTERNS);
+ s->pos = 0;
+ }
+
+ return 0;
+ }
+
+ if (!pulse && duration >= BPF_PARAM(trail_space)) {
+ for (i = 0; i < MAX_PATTERNS; i++) {
+ key = i;
+ p = bpf_map_lookup_elem(&raw_map, &key);
+ // Make verifier happy. Should never come to pass
+ if (!p)
+ break;
+
+ // Has this pattern already mismatched?
+ if (bitmap_test(s->nomatch, i))
+ continue;
+
+ // Are we at the end of the pattern?
+ if (p->raw[pos] == 0)
+ bpf_rc_keydown(sample, BPF_PARAM(rc_protocol),
+ p->scancode, 0);
+ }
+
+ bitmap_zero(s->nomatch, MAX_PATTERNS);
+ s->pos = 0;
+ } else {
+ for (i = 0; i < MAX_PATTERNS; i++) {
+ key = i;
+ p = bpf_map_lookup_elem(&raw_map, &key);
+ // Make verifier happy. Should never come to pass
+ if (!p)
+ break;
+
+ // Has this pattern already mismatched?
+ if (bitmap_test(s->nomatch, i))
+ continue;
+
+ // If the pattern ended, or does not match
+ if (p->raw[pos] == 0 ||
+ !eq_margin(duration, p->raw[pos]))
+ bitmap_set(s->nomatch, i);
+ }
+
+ s->pos++;
+ }
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";

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