ipa: mali-c55: Add Lens Shading Correction algorithm

Add a lens shading correction algorithm to the mali-c55 IPA. This
algorithm parses tables from Yaml in a easy to follow format before
munging them into Arm's interleaved mesh to be copied to the ISP.
A colour temperature estimate from the AGC statistics is used to
select the appropriate table to apply; this can be some interpolation
of two tables, in which case the colour temperature estimate is also
used to derive the coefficient that does the blending.

Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Acked-by: Nayden Kanchev <nayden.kanchev@arm.com>
Co-developed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/src/ipa/mali-c55/algorithms/lsc.h b/src/ipa/mali-c55/algorithms/lsc.h
new file mode 100644
index 00000000..e613277a
--- /dev/null
+++ b/src/ipa/mali-c55/algorithms/lsc.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Ideas On Board Oy
+ *
+ * lsc.h - Mali-C55 Lens shading correction algorithm
+ */
+
+#include <map>
+#include <tuple>
+
+#include "algorithm.h"
+
+namespace libcamera {
+
+namespace ipa::mali_c55::algorithms {
+
+class Lsc : public Algorithm
+{
+public:
+	Lsc() = default;
+	~Lsc() = default;
+
+	int init(IPAContext &context, const YamlObject &tuningData) override;
+	void prepare(IPAContext &context, const uint32_t frame,
+		     IPAFrameContext &frameContext,
+		     mali_c55_params_buffer *params) override;
+private:
+	static constexpr unsigned int kRedOffset = 0;
+	static constexpr unsigned int kGreenOffset = 1024;
+	static constexpr unsigned int kBlueOffset = 2048;
+
+	size_t fillConfigParamsBlock(mali_c55_params_block block) const;
+	size_t fillSelectionParamsBlock(mali_c55_params_block block,
+					uint8_t bank, uint8_t alpha) const;
+	std::tuple<uint8_t, uint8_t> findBankAndAlpha(uint32_t ct) const;
+
+	std::vector<uint32_t> mesh_ = std::vector<uint32_t>(3072);
+	std::vector<uint32_t> colourTemperatures_;
+	uint32_t meshScale_;
+	uint32_t meshSize_;
+};
+
+} /* namespace ipa::mali_c55::algorithms */
+
+} /* namespace libcamera */