marfrit
2a449632b9
Wires the Phase 8.3 FFmpeg loader through the Phase 8.2 chardev
bridge: kernel injects REQ_DECODE carrying a raw VP9 access unit,
daemon hands the bitstream to libavcodec via dlopen, sends
RESP_FRAME back with a content-dependent FNV-1a digest of the
decoded YUV planes. Pure CPU decode for now — Phase 8.5 swaps in
dmabuf + QPU dispatch.
Protocol (include/daedalus_v4l2_proto.h):
- New REQ_DECODE (kernel→daemon) and RESP_FRAME (daemon→kernel)
message types, with fixed-size payload structs.
- New DAEDALUS_CODEC_VP9/AV1/H264 enum (wire-stable so 8.6's
AV1+H.264 work doesn't move existing values).
- New DAEDALUS_DECODE_* status enum (OK / NO_FRAME / ERR_OPEN /
ERR_SEND / ERR_RECV / ERR_CODEC).
- Converted the prior `enum daedalus_msg_type` to #defines —
high-bit values exceed INT_MAX and tripped -Wpedantic on
userspace; kernel uABI headers use the same idiom.
Kernel (kernel/daedalus_v4l2_chardev.c):
- New debugfs entry /sys/kernel/debug/daedalus_v4l2/test_decode:
writing raw bitstream bytes wraps them in a REQ_DECODE
(codec=VP9 for Phase 8.4) and enqueues with an
auto-incrementing cookie.
- daedalus_chardev_write learned RESP_FRAME: parses the payload
and emits a single pr_info line with decode metadata. Keeps
existing PONG handling on the default arm.
Daemon (daemon/src/...):
- chardev_client.{c,h} — opens /dev/daedalus-v4l2, blocking read
loop, single-buffer write() responses (kernel chardev has only
.write, not .write_iter, so writev lands as -EINVAL —
discovered the hard way during first run).
- decoder.{c,h} — lazily-opened AVCodecContext per codec, shared
AVPacket/AVFrame pair, descriptor-driven plane walker
(av_pix_fmt_desc_get) so the same hash path covers YUV420P,
YUV422P, YUV444P, GBRP and other 8-bit planar layouts.
Generalised after first run decoded testsrc as GBRP (71)
rather than the assumed YUV420P.
- `daemon` command in main.c opens the chardev and runs the loop
until SIGINT/SIGTERM. Cookie correlation handled end-to-end.
- ffmpeg_loader gained av_pix_fmt_desc_get (23 symbols total).
Build:
- CMakeLists adds chardev_client.c + decoder.c; explicit
-I../include for the shared protocol header.
- Still -Wall -Wextra -Wpedantic clean.
Verification on hertz (Pi 5, 6.12.75+rpt-rpi-2712):
$ ffmpeg ... -pix_fmt yuv420p -c:v libvpx-vp9 -frames:v 1 \
-y /tmp/vp9_test.ivf
$ python3 ... strip IVF framing → vp9_keyframe.bin (3268 B)
$ sudo insmod kernel/daedalus_v4l2.ko
$ daedalus_v4l2_daemon -v daemon &
$ sudo dd if=vp9_keyframe.bin \
of=/sys/kernel/debug/daedalus_v4l2/test_decode
daemon: REQ_DECODE cookie=2 → decoded yuv420p 320x240
fnv1a=0x6ef10d71 luma=76800 chroma=38400
kernel: RESP_FRAME cookie=2 status=0 320x240 pixfmt=0
fnv1a=0x6ef10d71 ← matches daemon ✓
Hash properties verified:
cookie=2 testsrc 3268 B → 0x6ef10d71 (first decode)
cookie=3 red 44 B → 0x7f6e5dc5 (content-dependent ✓)
cookie=4 testsrc 3268 B → 0x6ef10d71 (deterministic ✓)
cookie=5 64 B random → status=101 (ERR_SEND, daemon alive)
Daemon survives bad input (FFmpeg "Invalid sync code" wrapped
into structured ERR_SEND response). Clean SIGTERM shutdown,
clean rmmod.
Phase 8.4 acceptance criteria met:
- ✓ end-to-end kernel→daemon→FFmpeg→kernel round-trip
- ✓ cookie correlation per request/response pair
- ✓ content-dependent + deterministic digest
- ✓ structured error responses (no daemon crash on bad input)
- ✓ clean teardown (SIGTERM + rmmod)
- ✓ builds clean on both kernel kbuild and daemon CMake
Per correctness-before-speed:
- Real chardev I/O (no shortcuts, no select-loop hacks)
- Real FFmpeg AVCodecContext lifecycle (lazily opened, properly
freed on cleanup)
- Descriptor-driven plane walk (generalises across pix_fmts)
- Structured error path (not just log-and-continue)
- All resource paths cleaned up on every error branch
- Documented why FNV-1a digest, why write() not writev(), why
pix_desc walk in docs/phase_8_4_closure.md
Phase 8.5 next: V4L2 m2m queue submits REQ_DECODE from
vidioc_qbuf; dmabuf carries actual pixel data so the chardev's
64 KiB cap doesn't gate frame size; begin substituting
daedalus_dispatch_* into the daemon's decode path.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
56 lines
1.3 KiB
CMake
56 lines
1.3 KiB
CMake
# SPDX-License-Identifier: BSD-2-Clause
|
||
#
|
||
# daedalus-v4l2 userspace daemon — CMake build.
|
||
#
|
||
# Notes:
|
||
# - FFmpeg is dlopen'd at runtime (Option γ), so we link only
|
||
# -ldl + -lpthread. Headers from libavformat-dev /
|
||
# libavcodec-dev / libavutil-dev are used at compile time
|
||
# for struct definitions.
|
||
# - Strict warnings enforced.
|
||
|
||
cmake_minimum_required(VERSION 3.20)
|
||
project(daedalus_v4l2_daemon C)
|
||
|
||
set(CMAKE_C_STANDARD 11)
|
||
set(CMAKE_C_STANDARD_REQUIRED ON)
|
||
|
||
if (NOT CMAKE_BUILD_TYPE)
|
||
set(CMAKE_BUILD_TYPE Release)
|
||
endif()
|
||
|
||
add_compile_options(-Wall -Wextra -Wpedantic
|
||
-Wno-unused-parameter)
|
||
|
||
# FFmpeg headers (we dlopen the libs but include the headers for
|
||
# struct definitions). pkg-config is the canonical way.
|
||
find_package(PkgConfig REQUIRED)
|
||
pkg_check_modules(FFMPEG REQUIRED IMPORTED_TARGET
|
||
libavformat libavcodec libavutil)
|
||
|
||
add_executable(daedalus_v4l2_daemon
|
||
src/main.c
|
||
src/ffmpeg_loader.c
|
||
src/log.c
|
||
src/parser.c
|
||
src/decoder.c
|
||
src/chardev_client.c
|
||
)
|
||
|
||
target_include_directories(daedalus_v4l2_daemon
|
||
PRIVATE
|
||
src
|
||
${CMAKE_CURRENT_SOURCE_DIR}/../include
|
||
${FFMPEG_INCLUDE_DIRS}
|
||
)
|
||
|
||
# dl for dlopen, pthread for future threading work.
|
||
target_link_libraries(daedalus_v4l2_daemon
|
||
PRIVATE
|
||
dl
|
||
pthread
|
||
)
|
||
|
||
install(TARGETS daedalus_v4l2_daemon
|
||
RUNTIME DESTINATION /usr/local/bin)
|