ipa: ipu3: convert AGC to the new algorithm interface

In preparation for using the AGC through the new algorithm interfaces,
convert the existing code to use the new function types.

Now that the process call is rewritten, re-enable the compiler flag to
warn when a function declaration hides virtual functions from a base class
(-Woverloaded-virtual).

We never use converged_ so remove its declaration. The controls may not
need to be updated at each call, but it should be decided on the context
side and not by a specific call by using a lock status in the Agc
structure for instance.

As the params_ local variable is not useful anymore, remove it here
too.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

5 files changed, 45 insertions, 38 deletions

diff --git a/meson.build b/meson.build
index 4a10e2b6..a49c484f 100644
--- a/meson.build
+++ b/meson.build
@@ -108,10 +108,6 @@ if cc.has_argument('-Wno-c99-designator')
     ]
 endif
 
-# Do not warn when a function declaration hides virtual functions from
-# a base class
-cpp_arguments += '-Wno-overloaded-virtual'
-
 c_arguments += common_arguments
 cpp_arguments += common_arguments
 
diff --git a/src/ipa/ipu3/ipa_context.h b/src/ipa/ipu3/ipa_context.h
index 24dd8bf7..9d9444dc 100644
--- a/src/ipa/ipu3/ipa_context.h
+++ b/src/ipa/ipu3/ipa_context.h
@@ -25,6 +25,11 @@ struct IPASessionConfiguration {
 
 struct IPAFrameContext {
 	struct {
+		uint32_t exposure;
+		double gain;
+	} agc;
+
+	struct {
 		struct {
 			double red;
 			double green;
diff --git a/src/ipa/ipu3/ipu3.cpp b/src/ipa/ipu3/ipu3.cpp
index 823df34b..2468e94a 100644
--- a/src/ipa/ipu3/ipu3.cpp
+++ b/src/ipa/ipu3/ipu3.cpp
@@ -93,6 +93,22 @@
  */
 
 /**
+ * \struct IPAFrameContext::agc
+ * \brief Context for the Automatic Gain Control algorithm
+ *
+ * The exposure and gain determined are expected to be applied to the sensor
+ * at the earliest opportunity.
+ *
+ * \var IPAFrameContext::agc::exposure
+ * \brief Exposure time expressed as a number of lines
+ *
+ * \var IPAFrameContext::agc::gain
+ * \brief Analogue gain multiplier
+ *
+ * The gain should be adapted to the sensor specific gain code before applying.
+ */
+
+/**
  * \struct IPAFrameContext::awb
  * \brief Context for the Automatic White Balance algorithm
  *
@@ -183,7 +199,6 @@ private:
 
 	/* Local parameter storage */
 	struct IPAContext context_;
-	struct ipu3_uapi_params params_;
 };
 
 /**
@@ -361,8 +376,7 @@ int IPAIPU3::configure(const IPAConfigInfo &configInfo)
 
 	defVBlank_ = itVBlank->second.def().get<int32_t>();
 
-	/* Clean context and IPU3 parameters at configuration */
-	params_ = {};
+	/* Clean context at configuration */
 	context_ = {};
 
 	calculateBdsGrid(configInfo.bdsOutputSize);
@@ -375,7 +389,7 @@ int IPAIPU3::configure(const IPAConfigInfo &configInfo)
 
 	awbAlgo_ = std::make_unique<IPU3Awb>();
 	agcAlgo_ = std::make_unique<IPU3Agc>();
-	agcAlgo_->initialise(context_.configuration.grid.bdsGrid, sensorInfo_);
+	agcAlgo_->configure(context_, configInfo);
 
 	return 0;
 }
@@ -450,12 +464,9 @@ void IPAIPU3::processControls([[maybe_unused]] unsigned int frame,
 void IPAIPU3::fillParams(unsigned int frame, ipu3_uapi_params *params)
 {
 	for (auto const &algo : algorithms_)
-		algo->prepare(context_, &params_);
-
-	if (agcAlgo_->updateControls())
-		awbAlgo_->prepare(context_, &params_);
+		algo->prepare(context_, params);
 
-	*params = params_;
+	awbAlgo_->prepare(context_, params);
 
 	IPU3Action op;
 	op.op = ActionParamFilled;
@@ -472,14 +483,16 @@ void IPAIPU3::parseStatistics(unsigned int frame,
 	for (auto const &algo : algorithms_)
 		algo->process(context_, stats);
 
-	double gain = camHelper_->gain(gain_);
-	agcAlgo_->process(stats, exposure_, gain);
-	gain_ = camHelper_->gainCode(gain);
+	/* \todo These fields should not be written by the IPAIPU3 layer */
+	context_.frameContext.agc.gain = camHelper_->gain(gain_);
+	context_.frameContext.agc.exposure = exposure_;
+	agcAlgo_->process(context_, stats);
+	exposure_ = context_.frameContext.agc.exposure;
+	gain_ = camHelper_->gainCode(context_.frameContext.agc.gain);
 
 	awbAlgo_->process(context_, stats);
 
-	if (agcAlgo_->updateControls())
-		setControls(frame);
+	setControls(frame);
 
 	/* \todo Use VBlank value calculated from each frame exposure. */
 	int64_t frameDuration = sensorInfo_.lineLength * (defVBlank_ + sensorInfo_.outputSize.height) /
diff --git a/src/ipa/ipu3/ipu3_agc.cpp b/src/ipa/ipu3/ipu3_agc.cpp
index 20c2d3b4..1c156b89 100644
--- a/src/ipa/ipu3/ipu3_agc.cpp
+++ b/src/ipa/ipu3/ipu3_agc.cpp
@@ -51,20 +51,21 @@ static constexpr double kEvGainTarget = 0.5;
 static constexpr uint8_t kCellSize = 8;
 
 IPU3Agc::IPU3Agc()
-	: frameCount_(0), lastFrame_(0), converged_(false),
-	  updateControls_(false), iqMean_(0.0),
-	  lineDuration_(0s), maxExposureTime_(0s),
-	  prevExposure_(0s), prevExposureNoDg_(0s),
+	: frameCount_(0), lastFrame_(0), iqMean_(0.0), lineDuration_(0s),
+	  maxExposureTime_(0s), prevExposure_(0s), prevExposureNoDg_(0s),
 	  currentExposure_(0s), currentExposureNoDg_(0s)
 {
 }
 
-void IPU3Agc::initialise(struct ipu3_uapi_grid_config &bdsGrid, const IPACameraSensorInfo &sensorInfo)
+int IPU3Agc::configure(IPAContext &context, const IPAConfigInfo &configInfo)
 {
-	aeGrid_ = bdsGrid;
+	aeGrid_ = context.configuration.grid.bdsGrid;
 
-	lineDuration_ = sensorInfo.lineLength * 1.0s / sensorInfo.pixelRate;
+	lineDuration_ = configInfo.sensorInfo.lineLength * 1.0s
+		      / configInfo.sensorInfo.pixelRate;
 	maxExposureTime_ = kMaxExposure * lineDuration_;
+
+	return 0;
 }
 
 void IPU3Agc::processBrightness(const ipu3_uapi_stats_3a *stats)
@@ -144,8 +145,6 @@ void IPU3Agc::filterExposure()
 
 void IPU3Agc::lockExposureGain(uint32_t &exposure, double &gain)
 {
-	updateControls_ = false;
-
 	/* Algorithm initialization should wait for first valid frames */
 	/* \todo - have a number of frames given by DelayedControls ?
 	 * - implement a function for IIR */
@@ -155,7 +154,6 @@ void IPU3Agc::lockExposureGain(uint32_t &exposure, double &gain)
 	/* Are we correctly exposed ? */
 	if (std::abs(iqMean_ - kEvGainTarget * knumHistogramBins) <= 1) {
 		LOG(IPU3Agc, Debug) << "!!! Good exposure with iqMean = " << iqMean_;
-		converged_ = true;
 	} else {
 		double newGain = kEvGainTarget * knumHistogramBins / iqMean_;
 
@@ -178,20 +176,20 @@ void IPU3Agc::lockExposureGain(uint32_t &exposure, double &gain)
 			exposure = std::clamp(static_cast<uint32_t>(exposure * currentExposure_ / currentExposureNoDg_), kMinExposure, kMaxExposure);
 			newExposure = currentExposure_ / exposure;
 			gain = std::clamp(static_cast<uint32_t>(gain * currentExposure_ / newExposure), kMinGain, kMaxGain);
-			updateControls_ = true;
 		} else if (currentShutter >= maxExposureTime_) {
 			gain = std::clamp(static_cast<uint32_t>(gain * currentExposure_ / currentExposureNoDg_), kMinGain, kMaxGain);
 			newExposure = currentExposure_ / gain;
 			exposure = std::clamp(static_cast<uint32_t>(exposure * currentExposure_ / newExposure), kMinExposure, kMaxExposure);
-			updateControls_ = true;
 		}
 		LOG(IPU3Agc, Debug) << "Adjust exposure " << exposure * lineDuration_ << " and gain " << gain;
 	}
 	lastFrame_ = frameCount_;
 }
 
-void IPU3Agc::process(const ipu3_uapi_stats_3a *stats, uint32_t &exposure, double &gain)
+void IPU3Agc::process(IPAContext &context, const ipu3_uapi_stats_3a *stats)
 {
+	uint32_t &exposure = context.frameContext.agc.exposure;
+	double &gain = context.frameContext.agc.gain;
 	processBrightness(stats);
 	lockExposureGain(exposure, gain);
 	frameCount_++;
diff --git a/src/ipa/ipu3/ipu3_agc.h b/src/ipa/ipu3/ipu3_agc.h
index 2d86127d..0e922664 100644
--- a/src/ipa/ipu3/ipu3_agc.h
+++ b/src/ipa/ipu3/ipu3_agc.h
@@ -29,10 +29,8 @@ public:
 	IPU3Agc();
 	~IPU3Agc() = default;
 
-	void initialise(struct ipu3_uapi_grid_config &bdsGrid, const IPACameraSensorInfo &sensorInfo);
-	void process(const ipu3_uapi_stats_3a *stats, uint32_t &exposure, double &gain);
-	bool converged() { return converged_; }
-	bool updateControls() { return updateControls_; }
+	int configure(IPAContext &context, const IPAConfigInfo &configInfo) override;
+	void process(IPAContext &context, const ipu3_uapi_stats_3a *stats) override;
 
 private:
 	void processBrightness(const ipu3_uapi_stats_3a *stats);
@@ -44,9 +42,6 @@ private:
 	uint64_t frameCount_;
 	uint64_t lastFrame_;
 
-	bool converged_;
-	bool updateControls_;
-
 	double iqMean_;
 
 	Duration lineDuration_;