Signed-off-by: Sean Young <sean@xxxxxxxx> --- utils/keytable/bpf_protocols/Makefile.am | 2 +- utils/keytable/bpf_protocols/samsung36.c | 136 +++++++++++++++++++++++ 2 files changed, 137 insertions(+), 1 deletion(-) create mode 100644 utils/keytable/bpf_protocols/samsung36.c 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@xxxxxxxx> + +#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"; -- 2.24.1
