[v2,1/4] ipa: rpi: pisp: Add decompand support using PiSP hardware block

24558 diff mbox series

From: Sena Asotani <aso.fam429@gmail.com>

This patch integrates a new decompand algorithm that utilizes the PiSP
FE hardware block available on Raspberry Pi 5. The implementation
enables conversion of companded sensor data into linear format prior to
ISP processing.

Changes include:
- Implementation of decompand logic for controller and pipe interfaces
- Enabling decompand block by "rpi.decompand" in tuning.json

Signed-off-by: Sena Asotani <aso.fam429@gmail.com>
Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Tested-by: Nick Hollinghurst <nick.hollinghurst@raspberrypi.com>
---
 src/ipa/rpi/controller/decompand_status.h |  8 ++++
 src/ipa/rpi/controller/meson.build        |  1 +
 src/ipa/rpi/controller/rpi/decompand.cpp  | 58 +++++++++++++++++++++++
 src/ipa/rpi/controller/rpi/decompand.h    | 31 ++++++++++++
 src/ipa/rpi/pisp/pisp.cpp                 | 38 +++++++++++++++
 5 files changed, 136 insertions(+)
 create mode 100644 src/ipa/rpi/controller/decompand_status.h
 create mode 100644 src/ipa/rpi/controller/rpi/decompand.cpp
 create mode 100644 src/ipa/rpi/controller/rpi/decompand.h

Hi Naush

Thanks for the patch.

On Fri, 3 Oct 2025 at 13:18, Naushir Patuck <naush@raspberrypi.com> wrote:
>
> From: Sena Asotani <aso.fam429@gmail.com>
>
> This patch integrates a new decompand algorithm that utilizes the PiSP
> FE hardware block available on Raspberry Pi 5. The implementation
> enables conversion of companded sensor data into linear format prior to
> ISP processing.
>
> Changes include:
> - Implementation of decompand logic for controller and pipe interfaces
> - Enabling decompand block by "rpi.decompand" in tuning.json
>
> Signed-off-by: Sena Asotani <aso.fam429@gmail.com>
> Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
> Tested-by: Nick Hollinghurst <nick.hollinghurst@raspberrypi.com>
> ---
>  src/ipa/rpi/controller/decompand_status.h |  8 ++++
>  src/ipa/rpi/controller/meson.build        |  1 +
>  src/ipa/rpi/controller/rpi/decompand.cpp  | 58 +++++++++++++++++++++++
>  src/ipa/rpi/controller/rpi/decompand.h    | 31 ++++++++++++
>  src/ipa/rpi/pisp/pisp.cpp                 | 38 +++++++++++++++
>  5 files changed, 136 insertions(+)
>  create mode 100644 src/ipa/rpi/controller/decompand_status.h
>  create mode 100644 src/ipa/rpi/controller/rpi/decompand.cpp
>  create mode 100644 src/ipa/rpi/controller/rpi/decompand.h
>
> diff --git a/src/ipa/rpi/controller/decompand_status.h b/src/ipa/rpi/controller/decompand_status.h
> new file mode 100644
> index 000000000000..2d9888dca4f3
> --- /dev/null
> +++ b/src/ipa/rpi/controller/decompand_status.h
> @@ -0,0 +1,8 @@
> +#pragma once
> +
> +#include "libipa/pwl.h"
> +
> +struct DecompandStatus {
> +       uint32_t bitdepth;

I wonder if a short comment somewhere explaining how we use the
bitdepth would be useful? It wasn't immediately clear to me that we're
expecting a single mode with a single bit depth to need decompanding,
or all the modes (when bitdepth is zero).

But this minor point notwithstanding:

Reviewed-by: David Plowman <david.plowman@raspberrypi.com>

Thanks!
David

> +       libcamera::ipa::Pwl decompandCurve;
> +};
> diff --git a/src/ipa/rpi/controller/meson.build b/src/ipa/rpi/controller/meson.build
> index 74b74888bbff..c13c48539d10 100644
> --- a/src/ipa/rpi/controller/meson.build
> +++ b/src/ipa/rpi/controller/meson.build
> @@ -14,6 +14,7 @@ rpi_ipa_controller_sources = files([
>      'rpi/cac.cpp',
>      'rpi/ccm.cpp',
>      'rpi/contrast.cpp',
> +    'rpi/decompand.cpp',
>      'rpi/denoise.cpp',
>      'rpi/dpc.cpp',
>      'rpi/geq.cpp',
> diff --git a/src/ipa/rpi/controller/rpi/decompand.cpp b/src/ipa/rpi/controller/rpi/decompand.cpp
> new file mode 100644
> index 000000000000..2036750f82f4
> --- /dev/null
> +++ b/src/ipa/rpi/controller/rpi/decompand.cpp
> @@ -0,0 +1,58 @@
> +#include "decompand.h"
> +
> +#include <libcamera/base/log.h>
> +
> +#include "../decompand_status.h"
> +#include "../histogram.h"
> +
> +using namespace RPiController;
> +using namespace libcamera;
> +
> +LOG_DEFINE_CATEGORY(RPiDecompand)
> +
> +#define NAME "rpi.decompand"
> +
> +Decompand::Decompand(Controller *controller)
> +       : Algorithm(controller)
> +{
> +}
> +
> +char const *Decompand::name() const
> +{
> +       return NAME;
> +}
> +
> +int Decompand::read(const libcamera::YamlObject &params)
> +{
> +       config_.bitdepth = params["bitdepth"].get<uint32_t>(0);
> +       config_.decompandCurve = params["decompand_curve"].get<ipa::Pwl>(ipa::Pwl{});
> +       return config_.decompandCurve.empty() ? -EINVAL : 0;
> +}
> +
> +void Decompand::initialise()
> +{
> +}
> +
> +void Decompand::switchMode(CameraMode const &cameraMode,
> +                          [[maybe_unused]] Metadata *metadata)
> +{
> +       mode_ = cameraMode;
> +}
> +
> +void Decompand::prepare(Metadata *imageMetadata)
> +{
> +       DecompandStatus decompandStatus;
> +
> +       if (config_.bitdepth == 0 || mode_.bitdepth == config_.bitdepth) {
> +               decompandStatus.decompandCurve = config_.decompandCurve;
> +               imageMetadata->set("decompand.status", decompandStatus);
> +       }
> +}
> +
> +/* Register algorithm with the system. */
> +static Algorithm *create(Controller *controller)
> +{
> +       return new Decompand(controller);
> +}
> +
> +static RegisterAlgorithm reg(NAME, &create);
> diff --git a/src/ipa/rpi/controller/rpi/decompand.h b/src/ipa/rpi/controller/rpi/decompand.h
> new file mode 100644
> index 000000000000..38b26a21e6d5
> --- /dev/null
> +++ b/src/ipa/rpi/controller/rpi/decompand.h
> @@ -0,0 +1,31 @@
> +#pragma once
> +
> +#include <libipa/pwl.h>
> +
> +#include "../decompand_status.h"
> +
> +#include "algorithm.h"
> +
> +namespace RPiController {
> +
> +struct DecompandConfig {
> +       uint32_t bitdepth;
> +       libcamera::ipa::Pwl decompandCurve;
> +};
> +
> +class Decompand : public Algorithm
> +{
> +public:
> +       Decompand(Controller *controller = nullptr);
> +       char const *name() const override;
> +       int read(const libcamera::YamlObject &params) override;
> +       void initialise() override;
> +       void switchMode(CameraMode const &cameraMode, Metadata *metadata) override;
> +       void prepare(Metadata *imageMetadata) override;
> +
> +private:
> +       CameraMode mode_;
> +       DecompandConfig config_;
> +};
> +
> +} /* namespace RPiController */
> diff --git a/src/ipa/rpi/pisp/pisp.cpp b/src/ipa/rpi/pisp/pisp.cpp
> index 829b91258522..14ece12b0895 100644
> --- a/src/ipa/rpi/pisp/pisp.cpp
> +++ b/src/ipa/rpi/pisp/pisp.cpp
> @@ -32,6 +32,7 @@
>  #include "controller/cac_status.h"
>  #include "controller/ccm_status.h"
>  #include "controller/contrast_status.h"
> +#include "controller/decompand_status.h"
>  #include "controller/denoise_algorithm.h"
>  #include "controller/denoise_status.h"
>  #include "controller/dpc_status.h"
> @@ -113,6 +114,25 @@ int generateLut(const ipa::Pwl &pwl, uint32_t *lut, std::size_t lutSize,
>         return 0;
>  }
>
> +int generateDecompandLut(const ipa::Pwl &pwl, Span<uint16_t> lut)
> +{
> +       if (pwl.empty())
> +               return -EINVAL;
> +
> +       constexpr int step = 1024;
> +       for (std::size_t i = 0; i < lut.size(); ++i) {
> +               int x = i * step;
> +
> +               int y = pwl.eval(x);
> +               if (y < 0)
> +                       return -1;
> +
> +               lut[i] = static_cast<uint16_t>(std::min(y, 65535));
> +       }
> +
> +       return 0;
> +}
> +
>  void packLscLut(uint32_t packed[NumLscVertexes][NumLscVertexes],
>                 double const rgb[3][NumLscVertexes][NumLscVertexes])
>  {
> @@ -236,6 +256,7 @@ private:
>         void applyLensShading(const AlscStatus *alscStatus,
>                               pisp_be_global_config &global);
>         void applyDPC(const DpcStatus *dpcStatus, pisp_be_global_config &global);
> +       void applyDecompand(const DecompandStatus *decompandStatus);
>         void applySdn(const SdnStatus *sdnStatus, pisp_be_global_config &global);
>         void applyTdn(const TdnStatus *tdnStatus, const DeviceStatus *deviceStatus,
>                       pisp_be_global_config &global);
> @@ -351,6 +372,11 @@ void IpaPiSP::platformPrepareIsp([[maybe_unused]] const PrepareParams &params,
>                 if (noiseStatus)
>                         applyFocusStats(noiseStatus);
>
> +               DecompandStatus *decompandStatus =
> +                       rpiMetadata.getLocked<DecompandStatus>("decompand.status");
> +               if (decompandStatus)
> +                       applyDecompand(decompandStatus);
> +
>                 BlackLevelStatus *blackLevelStatus =
>                         rpiMetadata.getLocked<BlackLevelStatus>("black_level.status");
>                 if (blackLevelStatus)
> @@ -702,6 +728,18 @@ void IpaPiSP::applyDPC(const DpcStatus *dpcStatus, pisp_be_global_config &global
>         be_->SetDpc(dpc);
>  }
>
> +void IpaPiSP::applyDecompand(const DecompandStatus *decompandStatus)
> +{
> +       pisp_fe_global_config feGlobal;
> +       pisp_fe_decompand_config decompand = {};
> +
> +       if (!generateDecompandLut(decompandStatus->decompandCurve, decompand.lut)) {
> +               fe_->SetDecompand(decompand);
> +               feGlobal.enables |= PISP_FE_ENABLE_DECOMPAND;
> +               fe_->SetGlobal(feGlobal);
> +       }
> +}
> +
>  void IpaPiSP::applySdn(const SdnStatus *sdnStatus, pisp_be_global_config &global)
>  {
>         pisp_be_sdn_config sdn = {};
> --
> 2.43.0
>