[libcamera-devel] [PATCH v2 00/10] libcamera: ipu3: Allow zero-copy RAW stream

[Niklas Söderlund]

Hi,

This series removes the need to copy the buffer when capturing RAW
buffers from the IPU3 pipeline. This is made possible by allocating an
internal queue of buffers in the pipeline handler which is used when the
application does not provide an buffer for the RAW stream.

The first 9 out of 10 patches in this series cleans up the IPU3 pipeline
handler a but and breaks out the CIO2Device helper class into separate
cio.{cpp,h} files. The CIO2Device is also reworked to make its interface
more strict, making it easier to grasp what is going in in ipu3.cpp. I
plan to post similar patches breaking out the ImgU on top of this
series.

There is on issue with this series. If the camera is configured to
supply the application with more then one stream and one of them is a
RAW stream. Then the sequence number of the RAW buffers in all requests
are set to 0 before the request completes. This is due to that if two or
more streams are used the RAW buffer is always queued to the ImgU input
to serve as input to the vf and/or output buffers. When the RAW buffers
is dequeued from the ImgU input device the kernel sets the sequence
number to zero. I believe this is a kernel issue and should be fixed
there.

As the RPi pipeline handler already started using the copy approach we
can not yet rename to role nor remove the copyFrom() helper. I aim to
work on that once the approach taken in this series is agreed upon.

Niklas Söderlund (10):
  libcamera: stream: Initialize stride and bufferCount
  libcamera: ipu3: Remove id from camera names
  libcamera: ipu3: Fold mediaBusToFormat() into only caller
  libcamera: ipu3: Breakout stream assignment to new function
  libcamera: ipu3: Calculate number of buffers for ImgU
  libcamera: ipu3: cio2: Move the CIO2Device class to separate files
  libcamera: ipu3: cio2: Add function to generate configuration
  libcamera: ipu3: cio2: Make the V4L2 devices private
  libcamera: ipu3: cio2: Hide buffer allocation and freeing from users
  libcamera: ipu3: Allow zero-copy RAW stream capture

 src/libcamera/pipeline/ipu3/cio2.cpp    | 314 +++++++++++++++
 src/libcamera/pipeline/ipu3/cio2.h      |  68 ++++
 src/libcamera/pipeline/ipu3/ipu3.cpp    | 486 +++++-------------------
 src/libcamera/pipeline/ipu3/meson.build |   1 +
 src/libcamera/stream.cpp                |   5 +-
 5 files changed, 478 insertions(+), 396 deletions(-)
 create mode 100644 src/libcamera/pipeline/ipu3/cio2.cpp
 create mode 100644 src/libcamera/pipeline/ipu3/cio2.h

-- 
2.26.2