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authorSean Young <sean@mess.org>2020-01-28 22:01:34 +0000
committerSean Young <sean@mess.org>2020-03-12 09:04:53 +0000
commit6c05f42737642d5daa77d37f6c72c843a654b511 (patch)
treed9804b975fa52cdfc20442f33b16a826e995a0c6
parent0ac19363566e82d6975ee5df14c28013b059689f (diff)
keytable: new samsung36 bpf decoder
Signed-off-by: Sean Young <sean@mess.org>
-rw-r--r--utils/keytable/bpf_protocols/Makefile.am2
-rw-r--r--utils/keytable/bpf_protocols/samsung36.c136
2 files changed, 137 insertions, 1 deletions
diff --git a/utils/keytable/bpf_protocols/Makefile.am b/utils/keytable/bpf_protocols/Makefile.am
index 3423aba1..13be2794 100644
--- a/utils/keytable/bpf_protocols/Makefile.am
+++ b/utils/keytable/bpf_protocols/Makefile.am
@@ -10,7 +10,7 @@ CLANG_SYS_INCLUDES := $(shell $(CLANG) -v -E - </dev/null 2>&1 \
%.o: %.c bpf_helpers.h
$(CLANG) $(CLANG_SYS_INCLUDES) -D__linux__ -I$(top_srcdir)/include -target bpf -O2 -c $<
-PROTOCOLS = grundig.o pulse_distance.o pulse_length.o rc_mm.o manchester.o xbox-dvd.o imon_rsc.o raw.o
+PROTOCOLS = grundig.o pulse_distance.o pulse_length.o rc_mm.o manchester.o xbox-dvd.o imon_rsc.o raw.o samsung36.o
all: $(PROTOCOLS)
diff --git a/utils/keytable/bpf_protocols/samsung36.c b/utils/keytable/bpf_protocols/samsung36.c
new file mode 100644
index 00000000..1b09365f
--- /dev/null
+++ b/utils/keytable/bpf_protocols/samsung36.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Remote protocol used by some Samsung remotes. It has 36 bits and the
+// 16th bit is not really a bit, but a marker to distinguish it from
+// shorter samsung protocols.
+//
+// http://www.hifi-remote.com/wiki/index.php/DecodeIR#Samsung36
+// Copyright (C) 2020 Sean Young <sean@mess.org>
+
+#include <linux/lirc.h>
+#include <linux/bpf.h>
+
+#include "bpf_helpers.h"
+
+enum state {
+ STATE_INACTIVE,
+ STATE_HEADER_SPACE,
+ STATE_BITS_SPACE,
+ STATE_BITS_PULSE,
+ STATE_TRAILER,
+};
+
+struct decoder_state {
+ unsigned long bits;
+ enum state state;
+ unsigned int count;
+};
+
+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,
+};
+
+// 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 = 300;
+int rc_protocol = 69;
+
+#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("samsung36")
+int bpf_decoder(unsigned int *sample)
+{
+ unsigned int key = 0;
+ struct decoder_state *s = bpf_map_lookup_elem(&decoder_state_map, &key);
+
+ 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);
+
+ switch (s->state) {
+ case STATE_INACTIVE:
+ if (pulse && eq_margin(duration, 4500)) {
+ s->bits = 0;
+ s->state = STATE_HEADER_SPACE;
+ s->count = 0;
+ }
+ break;
+ case STATE_HEADER_SPACE:
+ if (!pulse && eq_margin(duration, 4500))
+ s->state = STATE_BITS_PULSE;
+ else
+ s->state = STATE_INACTIVE;
+ break;
+ case STATE_BITS_PULSE:
+ if (pulse && eq_margin(duration, 500))
+ s->state = STATE_BITS_SPACE;
+ else
+ s->state = STATE_INACTIVE;
+ break;
+ case STATE_BITS_SPACE:
+ if (pulse) {
+ s->state = STATE_INACTIVE;
+ break;
+ }
+
+ s->count++;
+
+ if (s->count == 17) {
+ if (eq_margin(duration, 4450)) {
+ s->state = STATE_BITS_PULSE;
+ } else {
+ s->state = STATE_INACTIVE;
+ }
+ break;
+ }
+
+ s->bits <<= 1;
+
+ if (eq_margin(duration, 1600)) {
+ s->bits |= 1;
+ } else if (!eq_margin(duration, 500)) {
+ s->state = STATE_INACTIVE;
+ break;
+ }
+
+ if (s->count == 37)
+ s->state = STATE_TRAILER;
+ else
+ s->state = STATE_BITS_PULSE;
+ break;
+ case STATE_TRAILER:
+ if (pulse && eq_margin(duration, 500)) {
+ bpf_rc_keydown(sample, BPF_PARAM(rc_protocol), s->bits, 0);
+ }
+
+ s->state = STATE_INACTIVE;
+ }
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";

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