[v2,09/12] ipa: rkisp1: goc: Re-work to use GammaAlgorithm class
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Message ID 20260626-ipu3-libipa-rework-v2-9-41546e23de3e@ideasonboard.com
State New
Headers show
Series
  • libipa: Re-work IPU3 IPA to use libipa algorithms
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Commit Message

Dan Scally June 26, 2026, 1:05 p.m. UTC 
Re-work the RkISP1 Gamma Out Correction algorithm to use the new
GammaAlgorithm class from libipa, which allows us to share an
implementation with the other IPAs.

Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Changes in v2:

        - Fixed includes
	- Dropped the comment explaining how gamma correction is
	  implemented - it's on libipa gamma now
	- Dropped unused variable kDefaultGamma
---
 src/ipa/rkisp1/algorithms/goc.cpp | 63 +++++++++++----------------------------
 src/ipa/rkisp1/algorithms/goc.h   |  7 ++++-
 src/ipa/rkisp1/ipa_context.h      | 10 ++-----
 3 files changed, 26 insertions(+), 54 deletions(-)

Patch
diff mbox series 

diff --git a/src/ipa/rkisp1/algorithms/goc.cpp b/src/ipa/rkisp1/algorithms/goc.cpp
index e8f64bf3d5e028c2013d37b7ef9fe90b737fad5f..e3bea4bbef186dde28fdd5a3aa14b7662a9ffe69 100644
--- a/src/ipa/rkisp1/algorithms/goc.cpp
+++ b/src/ipa/rkisp1/algorithms/goc.cpp
@@ -6,10 +6,11 @@ 
  */
 #include "goc.h"
 
+#include <array>
 #include <cmath>
 
 #include <libcamera/base/log.h>
-#include <libcamera/base/utils.h>
+#include <libcamera/base/span.h>
 
 #include <libcamera/control_ids.h>
 
@@ -29,21 +30,13 @@  namespace ipa::rkisp1::algorithms {
  * \class GammaOutCorrection
  * \brief RkISP1 Gamma out correction
  *
- * This algorithm implements the gamma out curve for the RkISP1. It defaults to
- * a gamma value of 2.2.
- *
- * As gamma is internally represented as a piecewise linear function with only
- * 17 knots, the difference between gamma=2.2 and sRGB gamma is minimal.
- * Therefore sRGB gamma was not implemented as special case.
- *
- * Useful links:
- * - https://www.cambridgeincolour.com/tutorials/gamma-correction.htm
- * - https://en.wikipedia.org/wiki/SRGB
+ * This algorithm implements the gamma out curve for the RkISP1 using the
+ * libipa GammaAlgorithm class.
  */
 
 LOG_DEFINE_CATEGORY(RkISP1Gamma)
 
-const float kDefaultGamma = 2.2f;
+static constexpr unsigned int kNumLutSegments = RKISP1_CIF_ISP_GAMMA_OUT_MAX_SAMPLES_V10 - 1;
 
 /**
  * \copydoc libcamera::ipa::Algorithm::init
@@ -57,10 +50,12 @@  int GammaOutCorrection::init(IPAContext &context, const ValueNode &tuningData)
 		return -EINVAL;
 	}
 
-	defaultGamma_ = tuningData["gamma"].get<double>(kDefaultGamma);
-	context.ctrlMap[&controls::Gamma] = ControlInfo(0.1f, 10.0f, defaultGamma_);
+	std::array<unsigned int, kNumLutSegments> segments = {
+		 64,  64,  64,  64, 128, 128, 128, 128,
+		256, 256, 256, 512, 512, 512, 512, 512
+	};
 
-	return 0;
+	return gammaAlgo_.init(context.ctrlMap, tuningData, segments);
 }
 
 /**
@@ -69,7 +64,7 @@  int GammaOutCorrection::init(IPAContext &context, const ValueNode &tuningData)
 int GammaOutCorrection::configure(IPAContext &context,
 				  [[maybe_unused]] const IPACameraSensorInfo &configInfo)
 {
-	context.activeState.goc.gamma = defaultGamma_;
+	gammaAlgo_.configure(context.activeState.gamma);
 	return 0;
 }
 
@@ -80,17 +75,8 @@  void GammaOutCorrection::queueRequest(IPAContext &context, const uint32_t frame,
 				      IPAFrameContext &frameContext,
 				      const ControlList &controls)
 {
-	if (frame == 0)
-		frameContext.goc.update = true;
-
-	const auto &gamma = controls.get(controls::Gamma);
-	if (gamma) {
-		context.activeState.goc.gamma = *gamma;
-		frameContext.goc.update = true;
-		LOG(RkISP1Gamma, Debug) << "Set gamma to " << *gamma;
-	}
-
-	frameContext.goc.gamma = context.activeState.goc.gamma;
+	gammaAlgo_.queueRequest(context.activeState.gamma, frame,
+				frameContext.gamma, controls);
 }
 
 /**
@@ -104,29 +90,14 @@  void GammaOutCorrection::prepare(IPAContext &context,
 	ASSERT(context.hw.numGammaOutSamples ==
 	       RKISP1_CIF_ISP_GAMMA_OUT_MAX_SAMPLES_V10);
 
-	if (!frameContext.goc.update)
+	if (!frameContext.gamma.update)
 		return;
 
-	/*
-	 * The logarithmic segments as specified in the reference.
-	 * Plus an additional 0 to make the loop easier
-	 */
-	static constexpr std::array<unsigned int, RKISP1_CIF_ISP_GAMMA_OUT_MAX_SAMPLES_V10> segments = {
-		64, 64, 64, 64, 128, 128, 128, 128, 256,
-		256, 256, 512, 512, 512, 512, 512, 0
-	};
-
 	auto config = params->block<BlockType::Goc>();
 	config.setEnabled(true);
 
-	__u16 *gamma_y = config->gamma_y;
-
-	unsigned x = 0;
-	for (const auto [i, size] : utils::enumerate(segments)) {
-		gamma_y[i] = std::pow(x / 4096.0, 1.0 / frameContext.goc.gamma) * 1023.0;
-		x += size;
-	}
-
+	Span<uint16_t> lut{ config->gamma_y };
+	gammaAlgo_.prepare(frameContext.gamma, lut);
 	config->mode = RKISP1_CIF_ISP_GOC_MODE_LOGARITHMIC;
 }
 
@@ -139,7 +110,7 @@  void GammaOutCorrection::process([[maybe_unused]] IPAContext &context,
 				 [[maybe_unused]] const rkisp1_stat_buffer *stats,
 				 ControlList &metadata)
 {
-	metadata.set(controls::Gamma, frameContext.goc.gamma);
+	gammaAlgo_.process(frameContext.gamma, metadata);
 }
 
 REGISTER_IPA_ALGORITHM(GammaOutCorrection, "GammaOutCorrection")
diff --git a/src/ipa/rkisp1/algorithms/goc.h b/src/ipa/rkisp1/algorithms/goc.h
index bd79fe19cc86b8aefa2603e98e9d7130b44105d9..767d707b2758a89db286ab62d8f20d7a01912a2a 100644
--- a/src/ipa/rkisp1/algorithms/goc.h
+++ b/src/ipa/rkisp1/algorithms/goc.h
@@ -9,6 +9,11 @@ 
 
 #include "algorithm.h"
 
+#include <linux/rkisp1-config.h>
+
+#include <libipa/fixedpoint.h>
+#include <libipa/gamma.h>
+
 namespace libcamera {
 
 namespace ipa::rkisp1::algorithms {
@@ -35,7 +40,7 @@  public:
 		     ControlList &metadata) override;
 
 private:
-	float defaultGamma_;
+	GammaAlgorithm<RKISP1_CIF_ISP_GAMMA_OUT_MAX_SAMPLES_V10, UQ<0, 10>> gammaAlgo_;
 };
 
 } /* namespace ipa::rkisp1::algorithms */
diff --git a/src/ipa/rkisp1/ipa_context.h b/src/ipa/rkisp1/ipa_context.h
index 7b4346c54ed2b8850ed147b0ce2b8a20155b80cf..8011c353c4eaade85d0a0007b44de8af7beaa9d6 100644
--- a/src/ipa/rkisp1/ipa_context.h
+++ b/src/ipa/rkisp1/ipa_context.h
@@ -30,6 +30,7 @@ 
 #include "libipa/ccm.h"
 #include "libipa/fc_queue.h"
 #include "libipa/fixedpoint.h"
+#include "libipa/gamma.h"
 #include "libipa/lsc.h"
 
 namespace libcamera {
@@ -127,9 +128,7 @@  struct IPAActiveState {
 		uint8_t sharpness;
 	} filter;
 
-	struct {
-		double gamma;
-	} goc;
+	ipa::gamma::ActiveState gamma;
 
 	struct {
 		double lux;
@@ -194,10 +193,7 @@  struct IPAFrameContext : public FrameContext {
 		bool update;
 	} filter;
 
-	struct {
-		double gamma;
-		bool update;
-	} goc;
+	ipa::gamma::FrameContext gamma;
 
 	struct {
 		uint32_t exposure;