1 files changed, 73 insertions, 0 deletions
diff --git a/src/ipa/ipu3/algorithms/af.h b/src/ipa/ipu3/algorithms/af.h
new file mode 100644
index 00000000..68126d46
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+++ b/src/ipa/ipu3/algorithms/af.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021, Red Hat
+ *
+ * IPU3 Af algorithm
+ */
+
+#pragma once
+
+#include <linux/intel-ipu3.h>
+
+#include <libcamera/base/utils.h>
+
+#include <libcamera/geometry.h>
+
+#include "algorithm.h"
+
+namespace libcamera {
+
+namespace ipa::ipu3::algorithms {
+
+class Af : public Algorithm
+{
+	/* The format of y_table. From ipu3-ipa repo */
+	typedef struct __attribute__((packed)) y_table_item {
+		uint16_t y1_avg;
+		uint16_t y2_avg;
+	} y_table_item_t;
+public:
+	Af();
+	~Af() = default;
+
+	int configure(IPAContext &context, const IPAConfigInfo &configInfo) override;
+	void prepare(IPAContext &context, const uint32_t frame,
+		     IPAFrameContext &frameContext,
+		     ipu3_uapi_params *params) override;
+	void process(IPAContext &context, const uint32_t frame,
+		     IPAFrameContext &frameContext,
+		     const ipu3_uapi_stats_3a *stats,
+		     ControlList &metadata) override;
+
+private:
+	void afCoarseScan(IPAContext &context);
+	void afFineScan(IPAContext &context);
+	bool afScan(IPAContext &context, int min_step);
+	void afReset(IPAContext &context);
+	bool afNeedIgnoreFrame();
+	void afIgnoreFrameReset();
+	double afEstimateVariance(Span<const y_table_item_t> y_items, bool isY1);
+
+	bool afIsOutOfFocus(IPAContext &context);
+
+	/* VCM step configuration. It is the current setting of the VCM step. */
+	uint32_t focus_;
+	/* The best VCM step. It is a local optimum VCM step during scanning. */
+	uint32_t bestFocus_;
+	/* Current AF statistic variance. */
+	double currentVariance_;
+	/* The frames are ignore before starting measuring. */
+	uint32_t ignoreCounter_;
+	/* It is used to determine the derivative during scanning */
+	double previousVariance_;
+	/* The designated maximum range of focus scanning. */
+	uint32_t maxStep_;
+	/* If the coarse scan completes, it is set to true. */
+	bool coarseCompleted_;
+	/* If the fine scan completes, it is set to true. */
+	bool fineCompleted_;
+};
+
+} /* namespace ipa::ipu3::algorithms */
+
+} /* namespace libcamera */