[RFC PATCH 0/3] media: qcom: camss: CAMSS Offline Processing Engine support

[Loic Poulain <loic.poulain@oss.qualcomm.com>]

This RFC series introduces initial support for the Qualcomm CAMSS
Offline Processing Engine (OPE), as found on Agatti-based platforms.
Boards such as Arduino UNO-Q use this SoC family and will benefit
from hardware-assisted image processing enabled by this work.

This represents the first step toward enabling image processing beyond
raw capture on Qualcomm platforms by using hardware blocks for
operations such as debayering, 3A, and scaling.

The OPE sits outside the live capture pipeline. It operates on frames
fetched from system memory and writes processed results back to memory.
Because of this design, the OPE is not tied to any specific capture
interface: frames may come from CAMSS RDI or PIX paths, or from any
other producer capable of providing memory-backed buffers.

The hardware can sustain up to 580 megapixels per second, which is
sufficient to process a 10MPix stream at 60 fps or to handle four
parallel 2MPix (HD) streams at 60 fps.

The initial driver implementation relies on the V4L2 m2m framework
to keep the design simple while already enabling practical offline
processing workflows. This model also provides time-sharing across
multiple contexts through its built-in scheduling.

This first version is intentionally minimalistic. It provides a working
configuration using a fixed set of static processing parameters, mainly
to achieve correct and good-quality debayering.

Support for more advanced use-cases (dynamic parameters, statistics
outputs, additional data endpoints) will require evolving the driver
model beyond a pure m2m design. This may involve either moving away
from m2m, as other ISP drivers do, or extending it to support auxiliary
endpoints for parameters and statistics.

This series includes:
  - dt-binding schema for CAMSS OPE
  - initial CAMSS OPE driver
  - QCM2290 device tree node describing the hardware block.

Feedback on the architecture and expected uAPI direction is especially
welcome.

Loic Poulain (3):
  dt-bindings: media: qcom: Add CAMSS Offline Processing Engine (OPE)
  media: qcom: camss: Add CAMSS Offline Processing Engine driver
  arm64: dts: qcom: qcm2290: Add CAMSS OPE node

 .../bindings/media/qcom,camss-ope.yaml        |   87 +
 arch/arm64/boot/dts/qcom/agatti.dtsi          |   72 +
 drivers/media/platform/qcom/camss/Makefile    |    4 +
 drivers/media/platform/qcom/camss/camss-ope.c | 2058 +++++++++++++++++
 4 files changed, 2221 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/qcom,camss-ope.yaml
 create mode 100644 drivers/media/platform/qcom/camss/camss-ope.c

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