On 09/11/2018 05:09 PM, Maxime Jourdan wrote: > Hi everyone, > > This patch series adds support for the Amlogic video decoder, > as well as the corresponding dt bindings for GXBB/GXL/GXM chips. > > It features decoding for the following formats: > - MPEG 1 > - MPEG 2 > > The following formats will be added in future patches: > - MJPEG > - MPEG 4 (incl. Xvid, H.263) > - H.264 > - HEVC (incl. 10-bit) > > The following formats' development has still not started, but they are > supported by the hardware: > - VC1 > - VP9 > > The code was made in such a way to allow easy inclusion of those formats > in the future. > > The decoder is single instance. > > Files: > - vdec.c handles the V4L2 M2M logic > - esparser.c manages the hardware bitstream parser > - vdec_helpers.c provides helpers to DONE the dst buffers as well as > various common code used by the codecs > - vdec_1.c manages the VDEC_1 block of the vdec IP > - codec_mpeg12.c enables decoding for MPEG 1/2. > - vdec_platform.c links codec units with vdec units > (e.g vdec_1 with codec_mpeg12) and lists all the available > src/dst formats and requirements (max width/height, etc.), > per compatible chip. > > Firmwares are necessary to run the vdec. They can currently be found at: > https://github.com/chewitt/meson-firmware > > It was tested primarily with ffmpeg's v4l2-m2m implementation. For instance: > $ ffmpeg -c:v mpeg2_v4l2m2m -i sample_mpeg2.mkv -f null - > > Note: This patch series depends on > "[PATCH v3 0/3] soc: amlogic: add meson-canvas" > https://patchwork.kernel.org/cover/10573763/ > > The v4l2-compliance results are available below the patch diff. > > Changes since v1 [0]: > - use named interrupts in the bindings > - rewrite description in the bindings doc > - don't include the dts changes in the patch series > - fill the vb2 queues locks > - fill the video_device lock > - use helpers for wait_prepare and wait_finish vb2_ops > - remove unnecessary usleep in between esparser writes. > Extensive testing of every codec on GXBB/GXL didn't reveal > any fails without it, so just remove it. > - compile v4l2_compliance inside the git repo > - Check for plane number/plane size to pass the latest v4l2-compliance test > - Moved the single instance check (returning -EBUSY) to start/stop streaming > The check was previously in queue_setup but there was no great location to > clear it except for .close(). Actually, you can clear it by called VIDIOC_REQBUFS with count set to 0. That freed all buffers and clears this. Now, the difference between queue_setup and start/stop streaming is that if you do this in queue_setup you'll know early on that the device is busy. It is reasonable to assume that you only allocate buffers when you also want to start streaming, so that it a good place to know this quickly. Whereas with start_streaming you won't know until you call STREAMON, or even later if you start streaming with no buffers queued, since start_streaming won't be called until you have at least 'min_buffers_needed' buffers queued (1 for this driver). So in that case EBUSY won't be returned until the first VIDIOC_QBUF. My preference is to check this in queue_setup, but it is up to you to decide. Just be aware of the difference between the two options. Regards, Hans
