new file mode 100644
@@ -0,0 +1,218 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Ideas On Board Oy
+ *
+ * lsc.cpp - Mali-C55 Lens shading correction algorithm
+ */
+
+#include "lsc.h"
+
+#include "libcamera/internal/yaml_parser.h"
+
+namespace libcamera {
+
+namespace ipa::mali_c55::algorithms {
+
+LOG_DEFINE_CATEGORY(MaliC55Lsc)
+
+Lsc::Lsc()
+{
+}
+
+int Lsc::init([[maybe_unused]] IPAContext &context, const YamlObject &tuningData)
+{
+ if (!tuningData.contains("meshScale")) {
+ LOG(MaliC55Lsc, Error) << "meshScale missing from tuningData";
+ return -EINVAL;
+ }
+
+ meshScale_ = tuningData["meshScale"].get<uint32_t>(0);
+
+ const YamlObject &yamlSets = tuningData["sets"];
+ if (!yamlSets.isList()) {
+ LOG(MaliC55Lsc, Error) << "LSC tables missing or invalid";
+ return -EINVAL;
+ }
+
+ size_t tableSize = 0;
+ const auto &sets = yamlSets.asList();
+ for (const auto &yamlSet : sets) {
+ uint32_t ct = yamlSet["ct"].get<uint32_t>(0);
+
+ if (!ct) {
+ LOG(MaliC55Lsc, Error) << "Invalid colour temperature";
+ return -EINVAL;
+ }
+
+ if (std::count(colourTemperatures_.begin(),
+ colourTemperatures_.end(), ct)) {
+ LOG(MaliC55Lsc, Error)
+ << "Multiple sets found for colour temperature";
+ return -EINVAL;
+ }
+
+ std::vector<uint8_t> rTable =
+ yamlSet["r"].getList<uint8_t>().value_or(std::vector<uint8_t>{});
+ std::vector<uint8_t> gTable =
+ yamlSet["g"].getList<uint8_t>().value_or(std::vector<uint8_t>{});
+ std::vector<uint8_t> bTable =
+ yamlSet["b"].getList<uint8_t>().value_or(std::vector<uint8_t>{});
+
+ /*
+ * Some validation to do; only 16x16 and 32x32 tables of
+ * coefficients are acceptable, and all tables across all of the
+ * sets must be the same size. The first time we encounter a
+ * table we check that it is an acceptable size and if so make
+ * sure all other tables are of equal size.
+ */
+ if (!tableSize) {
+ if (rTable.size() != 256 && rTable.size() != 1024) {
+ LOG(MaliC55Lsc, Error)
+ << "Invalid table size for colour temperature " << ct;
+ return -EINVAL;
+ }
+ tableSize = rTable.size();
+ }
+
+ if (rTable.size() != tableSize ||
+ gTable.size() != tableSize ||
+ bTable.size() != tableSize) {
+ LOG(MaliC55Lsc, Error)
+ << "Invalid or mismatched table size for colour temperature " << ct;
+ return -EINVAL;
+ }
+
+ if (colourTemperatures_.size() >= 3) {
+ LOG(MaliC55Lsc, Error)
+ << "A maximum of 3 colour temperatures are supported";
+ return -EINVAL;
+ }
+
+ for (unsigned int i = 0; i < tableSize; i++) {
+ mesh_[kRedOffset + i] |=
+ (rTable[i] << (colourTemperatures_.size() * 8));
+ mesh_[kGreenOffset + i] |=
+ (gTable[i] << (colourTemperatures_.size() * 8));
+ mesh_[kBlueOffset + i] |=
+ (bTable[i] << (colourTemperatures_.size() * 8));
+ }
+
+ colourTemperatures_.push_back(ct);
+ }
+
+ if (tableSize == 256)
+ meshSize_ = 15;
+ else
+ meshSize_ = 31;
+
+ return 0;
+}
+
+void Lsc::fillConfigParamsBlock(mali_c55_params_block_header *block) const
+{
+ struct mali_c55_params_mesh_shading_config *config =
+ reinterpret_cast<struct mali_c55_params_mesh_shading_config *>(block);
+
+ config->header.type = MALI_C55_PARAM_MESH_SHADING_CONFIG;
+ config->header.enabled = true;
+ config->header.size = sizeof(struct mali_c55_params_mesh_shading_config);
+
+ config->mesh_show = false;
+ config->mesh_scale = meshScale_;
+ config->mesh_page_r = 0;
+ config->mesh_page_g = 1;
+ config->mesh_page_b = 2;
+ config->mesh_width = meshSize_;
+ config->mesh_height = meshSize_;
+
+ std::copy(mesh_.begin(), mesh_.end(), config->mesh);
+}
+
+void Lsc::fillSelectionParamsBlock(mali_c55_params_block_header *block,
+ uint8_t bank, uint8_t alpha) const
+{
+ struct mali_c55_params_mesh_shading_selection *config =
+ reinterpret_cast<struct mali_c55_params_mesh_shading_selection *>(block);
+
+ config->header.type = MALI_C55_PARAM_MESH_SHADING_SELECTION;
+ config->header.enabled = true;
+ config->header.size = sizeof(struct mali_c55_params_mesh_shading_selection);
+
+ config->mesh_alpha_bank_r = bank;
+ config->mesh_alpha_bank_g = bank;
+ config->mesh_alpha_bank_b = bank;
+ config->mesh_alpha_r = alpha;
+ config->mesh_alpha_g = alpha;
+ config->mesh_alpha_b = alpha;
+ config->mesh_strength = 0x1000; /* Otherwise known as 1.0 */
+}
+
+std::tuple<uint8_t, uint8_t> Lsc::findBankAndAlpha(uint32_t ct) const
+{
+ unsigned int i;
+
+ ct = std::clamp<uint32_t>(ct, colourTemperatures_.front(),
+ colourTemperatures_.back());
+
+ for (i = 0; i < colourTemperatures_.size() - 1; i++) {
+ if (ct >= colourTemperatures_[i] &&
+ ct <= colourTemperatures_[i + 1])
+ break;
+ }
+
+ /*
+ * With the clamping, we're guaranteed an index into colourTemperatures_
+ * that's <= colourTemperatures_.size() - 1.
+ */
+ uint8_t alpha = (255 * (ct - colourTemperatures_[i])) /
+ (colourTemperatures_[i + 1] - colourTemperatures_[i]);
+
+ return { i, alpha };
+}
+
+void Lsc::prepare(IPAContext &context, [[maybe_unused]] const uint32_t frame,
+ [[maybe_unused]] IPAFrameContext &frameContext,
+ mali_c55_params_block_header *block)
+{
+ /*
+ * For each frame we assess the colour temperature of the **last** frame
+ * and then select an appropriately blended table of coefficients based
+ * on that ct. As a bit of a shortcut, if we've only a single table the
+ * handling is somewhat simpler; if it's the first frame we just select
+ * that table and if we're past the first frame then we can just do
+ * nothing - the config will never change.
+ */
+ uint32_t temperatureK = context.activeState.agc.temperatureK;
+ uint8_t bank, alpha;
+
+ if (colourTemperatures_.size() == 1) {
+ if (frame > 0)
+ return;
+
+ bank = 0;
+ alpha = 0;
+ } else {
+ std::tie(bank, alpha) = findBankAndAlpha(temperatureK);
+ }
+
+ fillSelectionParamsBlock(block, bank, alpha);
+
+ if (frame > 0)
+ return;
+
+ char *params = reinterpret_cast<char *>(block);
+ block = reinterpret_cast<mali_c55_params_block_header *>
+ (params + sizeof(struct mali_c55_params_mesh_shading_selection));
+
+ /*
+ * If this is the first frame, we need to load the parsed coefficient
+ * tables from tuning data to the ISP.
+ */
+ fillConfigParamsBlock(block);
+}
+
+REGISTER_IPA_ALGORITHM(Lsc, "Lsc")
+
+} /* namespace ipa::mali_c55::algorithms */
+
+} /* namespace libcamera */
new file mode 100644
@@ -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();
+ ~Lsc() = default;
+
+ int init(IPAContext &context, const YamlObject &tuningData) override;
+ void prepare(IPAContext &context, const uint32_t frame,
+ IPAFrameContext &frameContext,
+ mali_c55_params_block_header *block) override;
+private:
+ static constexpr unsigned int kRedOffset = 0;
+ static constexpr unsigned int kGreenOffset = 1024;
+ static constexpr unsigned int kBlueOffset = 2048;
+
+ void fillConfigParamsBlock(mali_c55_params_block_header *block) const;
+ void fillSelectionParamsBlock(mali_c55_params_block_header *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 */
@@ -4,4 +4,5 @@ mali_c55_ipa_algorithms = files([
'agc.cpp',
'awb.cpp',
'blc.cpp',
+ 'lsc.cpp',
])