ipa: raspberrypi: Use the generic statistics structure in the algorithms

Repurpose the StatisticsPtr type from being a shared_ptr<bcm2835_isp_stats> to
shared_ptr<RPiController::Statistics>. This removes any hardware specific header
files and structures from the algorithms source code.

Add a new function in the Raspberry Pi IPA to populate the generic statistics
structure from the values provided by the hardware in the bcm2835_isp_stats
structure.

Update the Lux, AWB, AGC, ALSC, Contrast, and Focus algorithms to use the
generic statistics structure appropriately in their calculations. Additionally,
remove references to any hardware specific headers and defines in these source
files.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: David Plowman <david.plowman@raspberrypi.com>
Tested-by: Nick Hollinghurst <nick.hollinghurst@raspberrypi.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

11 files changed, 61 insertions, 71 deletions

diff --git a/src/ipa/raspberrypi/controller/rpi/af.cpp b/src/ipa/raspberrypi/controller/rpi/af.cpp
index 2e72f239..a6236518 100644
--- a/src/ipa/raspberrypi/controller/rpi/af.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/af.cpp
@@ -352,14 +352,12 @@ bool Af::getPhase(PdafData const &data, double &phase, double &conf) const
 	}
 }
 
-double Af::getContrast(struct bcm2835_isp_stats_focus const focus_stats[FOCUS_REGIONS]) const
+double Af::getContrast(const FocusRegions &focusStats) const
 {
 	uint32_t sumWc = 0;
 
-	for (unsigned i = 0; i < FOCUS_REGIONS; ++i) {
-		unsigned w = contrastWeights_[i];
-		sumWc += w * (focus_stats[i].contrast_val[1][1] >> 10);
-	}
+	for (unsigned i = 0; i < focusStats.numRegions(); ++i)
+		sumWc += contrastWeights_[i] * focusStats.get(i).val;
 
 	return (sumWeights_ == 0) ? 0.0 : (double)sumWc / (double)sumWeights_;
 }
@@ -666,7 +664,7 @@ void Af::prepare(Metadata *imageMetadata)
 void Af::process(StatisticsPtr &stats, [[maybe_unused]] Metadata *imageMetadata)
 {
 	(void)imageMetadata;
-	prevContrast_ = getContrast(stats->focus_stats);
+	prevContrast_ = getContrast(stats->focusRegions);
 }
 
 /* Controls */
diff --git a/src/ipa/raspberrypi/controller/rpi/af.h b/src/ipa/raspberrypi/controller/rpi/af.h
index f7baf897..7959371b 100644
--- a/src/ipa/raspberrypi/controller/rpi/af.h
+++ b/src/ipa/raspberrypi/controller/rpi/af.h
@@ -12,6 +12,12 @@
 #include "../pwl.h"
 
 /*
+ * \todo FOCUS_REGIONS is taken from bcm2835-isp.h, but should be made as a
+ * generic RegionStats structure.
+ */
+#define FOCUS_REGIONS 12
+
+/*
  * This algorithm implements a hybrid of CDAF and PDAF, favouring PDAF.
  *
  * Whenever PDAF is available, it is used in a continuous feedback loop.
@@ -117,7 +123,7 @@ private:
 
 	void computeWeights();
 	bool getPhase(PdafData const &data, double &phase, double &conf) const;
-	double getContrast(struct bcm2835_isp_stats_focus const focus_stats[FOCUS_REGIONS]) const;
+	double getContrast(const FocusRegions &focusStats) const;
 	void doPDAF(double phase, double conf);
 	bool earlyTerminationByPhase(double phase);
 	double findPeak(unsigned index) const;
diff --git a/src/ipa/raspberrypi/controller/rpi/agc.cpp b/src/ipa/raspberrypi/controller/rpi/agc.cpp
index 46dcc81a..868c30f0 100644
--- a/src/ipa/raspberrypi/controller/rpi/agc.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/agc.cpp
@@ -9,8 +9,6 @@
 #include <map>
 #include <tuple>
 
-#include <linux/bcm2835-isp.h>
-
 #include <libcamera/base/log.h>
 
 #include "../awb_status.h"
@@ -451,7 +449,7 @@ void Agc::process(StatisticsPtr &stats, Metadata *imageMetadata)
 	fetchCurrentExposure(imageMetadata);
 	/* Compute the total gain we require relative to the current exposure. */
 	double gain, targetY;
-	computeGain(stats.get(), imageMetadata, gain, targetY);
+	computeGain(stats, imageMetadata, gain, targetY);
 	/* Now compute the target (final) exposure which we think we want. */
 	computeTargetExposure(gain);
 	/*
@@ -585,24 +583,23 @@ void Agc::fetchAwbStatus(Metadata *imageMetadata)
 		LOG(RPiAgc, Debug) << "No AWB status found";
 }
 
-static double computeInitialY(bcm2835_isp_stats *stats, AwbStatus const &awb,
+static double computeInitialY(StatisticsPtr &stats, AwbStatus const &awb,
 			      double weights[], double gain)
 {
-	bcm2835_isp_stats_region *regions = stats->agc_stats;
 	/*
 	 * Note how the calculation below means that equal weights give you
 	 * "average" metering (i.e. all pixels equally important).
 	 */
 	double rSum = 0, gSum = 0, bSum = 0, pixelSum = 0;
-	for (unsigned int i = 0; i < AgcStatsSize; i++) {
-		double counted = regions[i].counted;
-		double rAcc = std::min(regions[i].r_sum * gain, ((1 << PipelineBits) - 1) * counted);
-		double gAcc = std::min(regions[i].g_sum * gain, ((1 << PipelineBits) - 1) * counted);
-		double bAcc = std::min(regions[i].b_sum * gain, ((1 << PipelineBits) - 1) * counted);
+	for (unsigned int i = 0; i < stats->agcRegions.numRegions(); i++) {
+		auto &region = stats->agcRegions.get(i);
+		double rAcc = std::min<double>(region.val.rSum * gain, ((1 << PipelineBits) - 1) * region.counted);
+		double gAcc = std::min<double>(region.val.gSum * gain, ((1 << PipelineBits) - 1) * region.counted);
+		double bAcc = std::min<double>(region.val.bSum * gain, ((1 << PipelineBits) - 1) * region.counted);
 		rSum += rAcc * weights[i];
 		gSum += gAcc * weights[i];
 		bSum += bAcc * weights[i];
-		pixelSum += counted * weights[i];
+		pixelSum += region.counted * weights[i];
 	}
 	if (pixelSum == 0.0) {
 		LOG(RPiAgc, Warning) << "computeInitialY: pixelSum is zero";
@@ -624,23 +621,23 @@ static double computeInitialY(bcm2835_isp_stats *stats, AwbStatus const &awb,
 
 static constexpr double EvGainYTargetLimit = 0.9;
 
-static double constraintComputeGain(AgcConstraint &c, Histogram &h, double lux,
+static double constraintComputeGain(AgcConstraint &c, const Histogram &h, double lux,
 				    double evGain, double &targetY)
 {
 	targetY = c.yTarget.eval(c.yTarget.domain().clip(lux));
 	targetY = std::min(EvGainYTargetLimit, targetY * evGain);
 	double iqm = h.interQuantileMean(c.qLo, c.qHi);
-	return (targetY * NUM_HISTOGRAM_BINS) / iqm;
+	return (targetY * h.bins()) / iqm;
 }
 
-void Agc::computeGain(bcm2835_isp_stats *statistics, Metadata *imageMetadata,
+void Agc::computeGain(StatisticsPtr &statistics, Metadata *imageMetadata,
 		      double &gain, double &targetY)
 {
 	struct LuxStatus lux = {};
 	lux.lux = 400; /* default lux level to 400 in case no metadata found */
 	if (imageMetadata->get("lux.status", lux) != 0)
 		LOG(RPiAgc, Warning) << "No lux level found";
-	Histogram h(statistics->hist[0].g_hist, NUM_HISTOGRAM_BINS);
+	const Histogram &h = statistics->yHist;
 	double evGain = status_.ev * config_.baseEv;
 	/*
 	 * The initial gain and target_Y come from some of the regions. After
diff --git a/src/ipa/raspberrypi/controller/rpi/agc.h b/src/ipa/raspberrypi/controller/rpi/agc.h
index cf04da19..f04896ca 100644
--- a/src/ipa/raspberrypi/controller/rpi/agc.h
+++ b/src/ipa/raspberrypi/controller/rpi/agc.h
@@ -96,7 +96,7 @@ private:
 	void housekeepConfig();
 	void fetchCurrentExposure(Metadata *imageMetadata);
 	void fetchAwbStatus(Metadata *imageMetadata);
-	void computeGain(bcm2835_isp_stats *statistics, Metadata *imageMetadata,
+	void computeGain(StatisticsPtr &statistics, Metadata *imageMetadata,
 			 double &gain, double &targetY);
 	void computeTargetExposure(double gain);
 	bool applyDigitalGain(double gain, double targetY);
diff --git a/src/ipa/raspberrypi/controller/rpi/alsc.cpp b/src/ipa/raspberrypi/controller/rpi/alsc.cpp
index a4afaf84..eb4e2f94 100644
--- a/src/ipa/raspberrypi/controller/rpi/alsc.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/alsc.cpp
@@ -310,19 +310,21 @@ double getCt(Metadata *metadata, double defaultCt)
 	return awbStatus.temperatureK;
 }
 
-static void copyStats(bcm2835_isp_stats_region regions[XY], StatisticsPtr &stats,
+static void copyStats(RgbyRegions &regions, StatisticsPtr &stats,
 		      AlscStatus const &status)
 {
-	bcm2835_isp_stats_region *inputRegions = stats->awb_stats;
+	if (!regions.numRegions())
+		regions.init(stats->awbRegions.size());
+
 	double *rTable = (double *)status.r;
 	double *gTable = (double *)status.g;
 	double *bTable = (double *)status.b;
-	for (int i = 0; i < XY; i++) {
-		regions[i].r_sum = inputRegions[i].r_sum / rTable[i];
-		regions[i].g_sum = inputRegions[i].g_sum / gTable[i];
-		regions[i].b_sum = inputRegions[i].b_sum / bTable[i];
-		regions[i].counted = inputRegions[i].counted;
-		/* (don't care about the uncounted value) */
+	for (unsigned int i = 0; i < stats->awbRegions.numRegions(); i++) {
+		auto r = stats->awbRegions.get(i);
+		r.val.rSum = static_cast<uint64_t>(r.val.rSum / rTable[i]);
+		r.val.gSum = static_cast<uint64_t>(r.val.gSum / gTable[i]);
+		r.val.bSum = static_cast<uint64_t>(r.val.bSum / bTable[i]);
+		regions.set(i, r);
 	}
 }
 
@@ -512,19 +514,19 @@ void resampleCalTable(double const calTableIn[XY],
 }
 
 /* Calculate chrominance statistics (R/G and B/G) for each region. */
-static_assert(XY == AWB_REGIONS, "ALSC/AWB statistics region mismatch");
-static void calculateCrCb(bcm2835_isp_stats_region *awbRegion, double cr[XY],
+static void calculateCrCb(const RgbyRegions &awbRegion, double cr[XY],
 			  double cb[XY], uint32_t minCount, uint16_t minG)
 {
 	for (int i = 0; i < XY; i++) {
-		bcm2835_isp_stats_region &zone = awbRegion[i];
-		if (zone.counted <= minCount ||
-		    zone.g_sum / zone.counted <= minG) {
+		auto s = awbRegion.get(i);
+
+		if (s.counted <= minCount || s.val.gSum / s.counted <= minG) {
 			cr[i] = cb[i] = InsufficientData;
 			continue;
 		}
-		cr[i] = zone.r_sum / (double)zone.g_sum;
-		cb[i] = zone.b_sum / (double)zone.g_sum;
+
+		cr[i] = s.val.rSum / (double)s.val.gSum;
+		cb[i] = s.val.bSum / (double)s.val.gSum;
 	}
 }
 
diff --git a/src/ipa/raspberrypi/controller/rpi/alsc.h b/src/ipa/raspberrypi/controller/rpi/alsc.h
index a858ef5a..9167c9ff 100644
--- a/src/ipa/raspberrypi/controller/rpi/alsc.h
+++ b/src/ipa/raspberrypi/controller/rpi/alsc.h
@@ -12,6 +12,7 @@
 
 #include "../algorithm.h"
 #include "../alsc_status.h"
+#include "../statistics.h"
 
 namespace RPiController {
 
@@ -98,7 +99,7 @@ private:
 	/* copy out the results from the async thread so that it can be restarted */
 	void fetchAsyncResults();
 	double ct_;
-	bcm2835_isp_stats_region statistics_[AlscCellsY * AlscCellsX];
+	RgbyRegions statistics_;
 	double asyncResults_[3][AlscCellsY][AlscCellsX];
 	double asyncLambdaR_[AlscCellsX * AlscCellsY];
 	double asyncLambdaB_[AlscCellsX * AlscCellsY];
diff --git a/src/ipa/raspberrypi/controller/rpi/awb.cpp b/src/ipa/raspberrypi/controller/rpi/awb.cpp
index 04d1c878..ef3435d6 100644
--- a/src/ipa/raspberrypi/controller/rpi/awb.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/awb.cpp
@@ -21,9 +21,6 @@ LOG_DEFINE_CATEGORY(RPiAwb)
 
 #define NAME "rpi.awb"
 
-static constexpr unsigned int AwbStatsSizeX = DEFAULT_AWB_REGIONS_X;
-static constexpr unsigned int AwbStatsSizeY = DEFAULT_AWB_REGIONS_Y;
-
 /*
  * todo - the locking in this algorithm needs some tidying up as has been done
  * elsewhere (ALSC and AGC).
@@ -401,17 +398,16 @@ void Awb::asyncFunc()
 }
 
 static void generateStats(std::vector<Awb::RGB> &zones,
-			  bcm2835_isp_stats_region *stats, double minPixels,
+			  RgbyRegions &stats, double minPixels,
 			  double minG)
 {
-	for (unsigned int i = 0; i < AwbStatsSizeX * AwbStatsSizeY; i++) {
+	for (auto const &region : stats) {
 		Awb::RGB zone;
-		double counted = stats[i].counted;
-		if (counted >= minPixels) {
-			zone.G = stats[i].g_sum / counted;
+		if (region.counted >= minPixels) {
+			zone.G = region.val.gSum / region.counted;
 			if (zone.G >= minG) {
-				zone.R = stats[i].r_sum / counted;
-				zone.B = stats[i].b_sum / counted;
+				zone.R = region.val.rSum / region.counted;
+				zone.B = region.val.bSum / region.counted;
 				zones.push_back(zone);
 			}
 		}
@@ -425,7 +421,7 @@ void Awb::prepareStats()
 	 * LSC has already been applied to the stats in this pipeline, so stop
 	 * any LSC compensation.  We also ignore config_.fast in this version.
 	 */
-	generateStats(zones_, statistics_->awb_stats, config_.minPixels,
+	generateStats(zones_, statistics_->awbRegions, config_.minPixels,
 		      config_.minG);
 	/*
 	 * apply sensitivities, so values appear to come from our "canonical"
@@ -641,7 +637,7 @@ void Awb::awbBayes()
 	 * valid... not entirely sure about this.
 	 */
 	Pwl prior = interpolatePrior();
-	prior *= zones_.size() / (double)(AwbStatsSizeX * AwbStatsSizeY);
+	prior *= zones_.size() / (double)(statistics_->awbRegions.numRegions());
 	prior.map([](double x, double y) {
 		LOG(RPiAwb, Debug) << "(" << x << "," << y << ")";
 	});
diff --git a/src/ipa/raspberrypi/controller/rpi/awb.h b/src/ipa/raspberrypi/controller/rpi/awb.h
index 2254c3ed..e7d49cd8 100644
--- a/src/ipa/raspberrypi/controller/rpi/awb.h
+++ b/src/ipa/raspberrypi/controller/rpi/awb.h
@@ -13,6 +13,7 @@
 #include "../awb_algorithm.h"
 #include "../pwl.h"
 #include "../awb_status.h"
+#include "../statistics.h"
 
 namespace RPiController {
 
diff --git a/src/ipa/raspberrypi/controller/rpi/contrast.cpp b/src/ipa/raspberrypi/controller/rpi/contrast.cpp
index 5b37edcb..a4f8c4f0 100644
--- a/src/ipa/raspberrypi/controller/rpi/contrast.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/contrast.cpp
@@ -106,7 +106,7 @@ Pwl computeStretchCurve(Histogram const &histogram,
 	 * bit.
 	 */
 	double histLo = histogram.quantile(config.loHistogram) *
-			(65536 / NUM_HISTOGRAM_BINS);
+			(65536 / histogram.bins());
 	double levelLo = config.loLevel * 65536;
 	LOG(RPiContrast, Debug)
 		<< "Move histogram point " << histLo << " to " << levelLo;
@@ -119,7 +119,7 @@ Pwl computeStretchCurve(Histogram const &histogram,
 	 * Keep the mid-point (median) in the same place, though, to limit the
 	 * apparent amount of global brightness shift.
 	 */
-	double mid = histogram.quantile(0.5) * (65536 / NUM_HISTOGRAM_BINS);
+	double mid = histogram.quantile(0.5) * (65536 / histogram.bins());
 	enhance.append(mid, mid);
 
 	/*
@@ -127,7 +127,7 @@ Pwl computeStretchCurve(Histogram const &histogram,
 	 * there up.
 	 */
 	double histHi = histogram.quantile(config.hiHistogram) *
-			(65536 / NUM_HISTOGRAM_BINS);
+			(65536 / histogram.bins());
 	double levelHi = config.hiLevel * 65536;
 	LOG(RPiContrast, Debug)
 		<< "Move histogram point " << histHi << " to " << levelHi;
@@ -158,7 +158,7 @@ Pwl applyManualContrast(Pwl const &gammaCurve, double brightness,
 void Contrast::process(StatisticsPtr &stats,
 		       [[maybe_unused]] Metadata *imageMetadata)
 {
-	Histogram histogram(stats->hist[0].g_hist, NUM_HISTOGRAM_BINS);
+	Histogram &histogram = stats->yHist;
 	/*
 	 * We look at the histogram and adjust the gamma curve in the following
 	 * ways: 1. Adjust the gamma curve so as to pull the start of the
diff --git a/src/ipa/raspberrypi/controller/rpi/focus.cpp b/src/ipa/raspberrypi/controller/rpi/focus.cpp
index 8c5029bd..ea3cc00e 100644
--- a/src/ipa/raspberrypi/controller/rpi/focus.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/focus.cpp
@@ -31,10 +31,9 @@ char const *Focus::name() const
 void Focus::process(StatisticsPtr &stats, Metadata *imageMetadata)
 {
 	FocusStatus status;
-	unsigned int i;
-	for (i = 0; i < FOCUS_REGIONS; i++)
-		status.focusMeasures[i] = stats->focus_stats[i].contrast_val[1][1] / 1000;
-	status.num = i;
+	for (unsigned int i = 0; i < stats->focusRegions.numRegions(); i++)
+		status.focusMeasures[i] = stats->focusRegions.get(i).val;
+	status.num = stats->focusRegions.numRegions();
 	imageMetadata->set("focus.status", status);
 
 	LOG(RPiFocus, Debug)
diff --git a/src/ipa/raspberrypi/controller/rpi/lux.cpp b/src/ipa/raspberrypi/controller/rpi/lux.cpp
index 9759186a..06625f3a 100644
--- a/src/ipa/raspberrypi/controller/rpi/lux.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/lux.cpp
@@ -6,8 +6,6 @@
  */
 #include <math.h>
 
-#include <linux/bcm2835-isp.h>
-
 #include <libcamera/base/log.h>
 
 #include "../device_status.h"
@@ -83,20 +81,12 @@ void Lux::process(StatisticsPtr &stats, Metadata *imageMetadata)
 	if (imageMetadata->get("device.status", deviceStatus) == 0) {
 		double currentGain = deviceStatus.analogueGain;
 		double currentAperture = deviceStatus.aperture.value_or(currentAperture_);
-		uint64_t sum = 0;
-		uint32_t num = 0;
-		uint32_t *bin = stats->hist[0].g_hist;
-		const int numBins = sizeof(stats->hist[0].g_hist) /
-				    sizeof(stats->hist[0].g_hist[0]);
-		for (int i = 0; i < numBins; i++)
-			sum += bin[i] * (uint64_t)i, num += bin[i];
-		/* add .5 to reflect the mid-points of bins */
-		double currentY = sum / (double)num + .5;
+		double currentY = stats->yHist.interQuantileMean(0, 1);
 		double gainRatio = referenceGain_ / currentGain;
 		double shutterSpeedRatio =
 			referenceShutterSpeed_ / deviceStatus.shutterSpeed;
 		double apertureRatio = referenceAperture_ / currentAperture;
-		double yRatio = currentY * (65536 / numBins) / referenceY_;
+		double yRatio = currentY * (65536 / stats->yHist.bins()) / referenceY_;
 		double estimatedLux = shutterSpeedRatio * gainRatio *
 				      apertureRatio * apertureRatio *
 				      yRatio * referenceLux_;