[v4,01/19] ipa: rkisp1: Add basic compression algorithm

24390 diff mbox series

The i.MX8 M Plus has a compression curve inside the compand block.  This
curve is necessary to process HDR stitched data and is useful for other
aspects like applying a digital gain to the incoming sensor data.

Add a basic algorithm for the compression curve. This algorithm has a
hardcoded input width of 20bit and output width of 12bit which matches
the imx8mp pipeline. Only a static gain is supported in this version.

Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>

---

Changes in v4:
- Moved activeState.compress.supported to
  configuration.compress.supported
- Added documentation
- Fixed typo in documentation
- Replaced constant with RKISP1_CIF_ISP_COMPAND_NUM_POINTS

Changes in v3:
- Removed unused member
- Fixed comment referencing copy-paste source
- Ensure activeState.compress.supported stays false if unsupported
---
 src/ipa/rkisp1/algorithms/compress.cpp | 102 +++++++++++++++++++++++++
 src/ipa/rkisp1/algorithms/compress.h   |  30 ++++++++
 src/ipa/rkisp1/algorithms/meson.build  |   1 +
 src/ipa/rkisp1/ipa_context.cpp         |  19 +++++
 src/ipa/rkisp1/ipa_context.h           |   9 +++
 5 files changed, 161 insertions(+)
 create mode 100644 src/ipa/rkisp1/algorithms/compress.cpp
 create mode 100644 src/ipa/rkisp1/algorithms/compress.h

Quoting Stefan Klug (2025-09-18 15:43:10)
> The i.MX8 M Plus has a compression curve inside the compand block.  This
> curve is necessary to process HDR stitched data and is useful for other
> aspects like applying a digital gain to the incoming sensor data.
> 
> Add a basic algorithm for the compression curve. This algorithm has a
> hardcoded input width of 20bit and output width of 12bit which matches
> the imx8mp pipeline. Only a static gain is supported in this version.
> 
> Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
> 
> ---
> 
> Changes in v4:
> - Moved activeState.compress.supported to
>   configuration.compress.supported
> - Added documentation
> - Fixed typo in documentation
> - Replaced constant with RKISP1_CIF_ISP_COMPAND_NUM_POINTS
> 
> Changes in v3:
> - Removed unused member
> - Fixed comment referencing copy-paste source
> - Ensure activeState.compress.supported stays false if unsupported
> ---
>  src/ipa/rkisp1/algorithms/compress.cpp | 102 +++++++++++++++++++++++++
>  src/ipa/rkisp1/algorithms/compress.h   |  30 ++++++++
>  src/ipa/rkisp1/algorithms/meson.build  |   1 +
>  src/ipa/rkisp1/ipa_context.cpp         |  19 +++++
>  src/ipa/rkisp1/ipa_context.h           |   9 +++
>  5 files changed, 161 insertions(+)
>  create mode 100644 src/ipa/rkisp1/algorithms/compress.cpp
>  create mode 100644 src/ipa/rkisp1/algorithms/compress.h
> 
> diff --git a/src/ipa/rkisp1/algorithms/compress.cpp b/src/ipa/rkisp1/algorithms/compress.cpp
> new file mode 100644
> index 000000000000..c31d71bd50d5
> --- /dev/null
> +++ b/src/ipa/rkisp1/algorithms/compress.cpp
> @@ -0,0 +1,102 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2025, Ideas On Board
> + *
> + * RkISP1 Compression curve
> + */
> +#include "compress.h"
> +
> +#include <linux/videodev2.h>
> +
> +#include <libcamera/base/log.h>
> +#include <libcamera/base/utils.h>
> +
> +#include "libcamera/internal/yaml_parser.h"
> +
> +#include "linux/rkisp1-config.h"
> +
> +/**
> + * \file compress.h
> + */
> +
> +namespace libcamera {
> +
> +namespace ipa::rkisp1::algorithms {
> +
> +/**
> + * \class Compress
> + * \brief RkISP1 Compress curve
> + *
> + * This algorithm implements support for the compression curve in the compand
> + * block available in the i.MX8 M Plus
> + *
> + * In its current version it only supports a static gain. This is useful for
> + * the agc algorithm to compensate for exposure/gain quantization effects.
> + *
> + * This algorithm doesn't have any configuration options. It needs to be
> + * configured per frame by other algorithms.
> + *
> + * Other algorithms can check configuration.compress.supported to see if
> + * compression is available. If it is available they can configure it per frame
> + * using frameContext.compress.enable and frameContext.compress.gain.
> + */
> +
> +LOG_DEFINE_CATEGORY(RkISP1Compress)
> +
> +constexpr static int kRkISP1CompressInBits = 20;
> +constexpr static int kRkISP1CompressOutBits = 12;
> +
> +/**
> + * \copydoc libcamera::ipa::Algorithm::configure
> + */
> +int Compress::configure(IPAContext &context,
> +                       [[maybe_unused]] const IPACameraSensorInfo &configInfo)
> +{
> +       if (context.configuration.paramFormat != V4L2_META_FMT_RK_ISP1_EXT_PARAMS ||
> +           !context.hw->compand) {
> +               LOG(RkISP1Compress, Warning)
> +                       << "Compression is not supported by the hardware or kernel.";
> +               return 0;
> +       }
> +
> +       context.configuration.compress.supported = true;
> +       return 0;
> +}
> +
> +/**
> + * \copydoc libcamera::ipa::Algorithm::prepare
> + */
> +void Compress::prepare([[maybe_unused]] IPAContext &context,
> +                      [[maybe_unused]] const uint32_t frame,
> +                      IPAFrameContext &frameContext,
> +                      RkISP1Params *params)
> +{
> +       auto comp = params->block<BlockType::CompandCompress>();
> +       comp.setEnabled(frameContext.compress.enable);
> +
> +       if (!frameContext.compress.enable)

Does this need any guard against the compress being supported ? Or will
compress.enable never get set in that case ?

I think that will be the case so if so:

Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

> +               return;
> +
> +       int xmax = (1 << kRkISP1CompressInBits);
> +       int ymax = (1 << kRkISP1CompressOutBits);
> +       int inLogStep = std::log2(xmax / RKISP1_CIF_ISP_COMPAND_NUM_POINTS);
> +
> +       for (unsigned int i = 0; i < RKISP1_CIF_ISP_COMPAND_NUM_POINTS; i++) {
> +               double x = (i + 1) * (1.0 / RKISP1_CIF_ISP_COMPAND_NUM_POINTS);
> +               double y = x * frameContext.compress.gain;
> +
> +               comp->px[i] = inLogStep;
> +               comp->x[i] = std::min<int>(x * xmax, xmax - 1);
> +               comp->y[i] = std::min<int>(y * ymax, ymax - 1);
> +       }
> +
> +       LOG(RkISP1Compress, Debug) << "Compression: " << kRkISP1CompressInBits
> +                                  << " bits to " << kRkISP1CompressOutBits
> +                                  << " bits gain: " << frameContext.compress.gain;
> +}
> +
> +REGISTER_IPA_ALGORITHM(Compress, "Compress")
> +
> +} /* namespace ipa::rkisp1::algorithms */
> +
> +} /* namespace libcamera */
> diff --git a/src/ipa/rkisp1/algorithms/compress.h b/src/ipa/rkisp1/algorithms/compress.h
> new file mode 100644
> index 000000000000..87797b8ebcc5
> --- /dev/null
> +++ b/src/ipa/rkisp1/algorithms/compress.h
> @@ -0,0 +1,30 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2025, Ideas On Board
> + *
> + * RkISP1 Compression curve
> + */
> +
> +#pragma once
> +
> +#include "algorithm.h"
> +
> +namespace libcamera {
> +
> +namespace ipa::rkisp1::algorithms {
> +
> +class Compress : public Algorithm
> +{
> +public:
> +       Compress() = default;
> +       ~Compress() = default;
> +
> +       int configure(IPAContext &context,
> +                     const IPACameraSensorInfo &configInfo) override;
> +       void prepare(IPAContext &context, const uint32_t frame,
> +                    IPAFrameContext &frameContext,
> +                    RkISP1Params *params) override;
> +};
> +
> +} /* namespace ipa::rkisp1::algorithms */
> +} /* namespace libcamera */
> diff --git a/src/ipa/rkisp1/algorithms/meson.build b/src/ipa/rkisp1/algorithms/meson.build
> index c66b0b70b82f..2e42a80cf99d 100644
> --- a/src/ipa/rkisp1/algorithms/meson.build
> +++ b/src/ipa/rkisp1/algorithms/meson.build
> @@ -5,6 +5,7 @@ rkisp1_ipa_algorithms = files([
>      'awb.cpp',
>      'blc.cpp',
>      'ccm.cpp',
> +    'compress.cpp',
>      'cproc.cpp',
>      'dpcc.cpp',
>      'dpf.cpp',
> diff --git a/src/ipa/rkisp1/ipa_context.cpp b/src/ipa/rkisp1/ipa_context.cpp
> index 6509610573c0..15cb0afe9fe8 100644
> --- a/src/ipa/rkisp1/ipa_context.cpp
> +++ b/src/ipa/rkisp1/ipa_context.cpp
> @@ -66,6 +66,14 @@ namespace libcamera::ipa::rkisp1 {
>   * operates in manual or automatic mode.
>   */
>  
> +/**
> + * \var IPASessionConfiguration::compress
> + * \brief Compress parameters configuration of the IPA
> + *
> + * \var IPASessionConfiguration::agc.supported
> + * \brief true if compression is supported and the algorithm is loaded
> + */
> +
>  /**
>   * \var IPASessionConfiguration::lsc
>   * \brief Lens Shading Correction configuration of the IPA
> @@ -377,6 +385,17 @@ namespace libcamera::ipa::rkisp1 {
>   * \brief Colour Correction Matrix
>   */
>  
> +/**
> + * \var IPAFrameContext::compress
> + * \brief Compress parameters for this frame
> + *
> + * \struct IPAFrameContext::compress.enable
> + * \brief True if compression is enabled
> + *
> + * \var IPAFrameContext::compress.gain
> + * \brief The gain applied with the compression curve
> + */
> +
>  /**
>   * \var IPAFrameContext::cproc
>   * \brief Color Processing parameters for this frame
> diff --git a/src/ipa/rkisp1/ipa_context.h b/src/ipa/rkisp1/ipa_context.h
> index 7ccc7b501aff..a723c79b04d9 100644
> --- a/src/ipa/rkisp1/ipa_context.h
> +++ b/src/ipa/rkisp1/ipa_context.h
> @@ -49,6 +49,10 @@ struct IPASessionConfiguration {
>                 bool enabled;
>         } awb;
>  
> +       struct {
> +               bool supported;
> +       } compress;
> +
>         struct {
>                 bool enabled;
>         } lsc;
> @@ -158,6 +162,11 @@ struct IPAFrameContext : public FrameContext {
>                 bool update;
>         } cproc;
>  
> +       struct {
> +               bool enable;
> +               double gain;
> +       } compress;
> +
>         struct {
>                 bool denoise;
>                 bool update;
> -- 
> 2.48.1
>