[PATCH v1 0/4] IR decoding using BPF

From: Sean Young
Date: Mon May 14 2018 - 17:11:48 EST


The kernel IR decoders support the most widely used IR protocols, but there
are many protocols which are not supported[1]. For example, the
lirc-remotes[2] repo has over 2700 remotes, many of which are not supported
by rc-core. There is a "long tail" of unsupported IR protocols.

IR encoding is done in such a way that some simple circuit can decode it;
therefore, bpf is ideal.

In order to support all these protocols, here we have bpf based IR decoding.
The idea is that user-space can define a decoder in bpf, attach it to
the rc device through the lirc chardev.

Separate work is underway to extend ir-keytable to have an extensive library
of bpf-based decoders, and a much expanded library of rc keymaps.

Another future application would be to compile IRP[3] to a IR BPF program, and
so support virtually every remote without having to write a decoder for each.

Thanks,

Sean Young

[1] http://www.hifi-remote.com/wiki/index.php?title=DecodeIR
[2] https://sourceforge.net/p/lirc-remotes/code/ci/master/tree/remotes/
[3] http://www.hifi-remote.com/wiki/index.php?title=IRP_Notation

Sean Young (4):
media: rc: introduce BPF_PROG_IR_DECODER
media: bpf: allow raw IR decoder bpf programs to be used
media: rc bpf: move ir_raw_event to uapi
samples/bpf: an example of a raw IR decoder

drivers/media/rc/Kconfig | 8 +
drivers/media/rc/Makefile | 1 +
drivers/media/rc/ir-bpf-decoder.c | 284 ++++++++++++++++++++++
drivers/media/rc/lirc_dev.c | 30 +++
drivers/media/rc/rc-core-priv.h | 15 ++
drivers/media/rc/rc-ir-raw.c | 5 +
include/linux/bpf_types.h | 3 +
include/media/rc-core.h | 19 +-
include/uapi/linux/bpf.h | 17 +-
include/uapi/linux/bpf_rcdev.h | 24 ++
kernel/bpf/syscall.c | 7 +
samples/bpf/Makefile | 4 +
samples/bpf/bpf_load.c | 9 +-
samples/bpf/grundig_decoder_kern.c | 112 +++++++++
samples/bpf/grundig_decoder_user.c | 54 ++++
tools/bpf/bpftool/prog.c | 1 +
tools/include/uapi/linux/bpf.h | 17 +-
tools/testing/selftests/bpf/bpf_helpers.h | 6 +
18 files changed, 594 insertions(+), 22 deletions(-)
create mode 100644 drivers/media/rc/ir-bpf-decoder.c
create mode 100644 include/uapi/linux/bpf_rcdev.h
create mode 100644 samples/bpf/grundig_decoder_kern.c
create mode 100644 samples/bpf/grundig_decoder_user.c

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2.17.0