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diff --git a/src/ipa/ipu3/algorithms/blc.cpp b/src/ipa/ipu3/algorithms/blc.cpp
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+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021, Google inc.
+ *
+ * blc.cpp - IPU3 Black Level Correction control
+ */
+
+#include "blc.h"
+
+#include <string.h>
+
+/**
+ * \file blc.h
+ * \brief IPU3 Black Level Correction control
+ */
+
+namespace libcamera {
+
+namespace ipa::ipu3::algorithms {
+
+/**
+ * \class BlackLevelCorrection
+ * \brief A class to handle black level correction
+ *
+ * The pixels output by the camera normally include a black level, because
+ * sensors do not always report a signal level of '0' for black. Pixels at or
+ * below this level should be considered black. To achieve that, the ImgU BLC
+ * algorithm subtracts a configurable offset from all pixels.
+ *
+ * The black level can be measured at runtime from an optical dark region of the
+ * camera sensor, or measured during the camera tuning process. The first option
+ * isn't currently supported.
+ */
+
+BlackLevelCorrection::BlackLevelCorrection()
+{
+}
+
+/**
+ * \brief Fill in the parameter structure, and enable black level correction
+ * \param context The shared IPA context
+ * \param params The IPU3 parameters
+ *
+ * Populate the IPU3 parameter structure with the correction values for each
+ * channel and enable the corresponding ImgU block processing.
+ */
+void BlackLevelCorrection::prepare([[maybe_unused]] IPAContext &context,
+			      ipu3_uapi_params *params)
+{
+	/*
+	 * The Optical Black Level correction values
+	 * \todo The correction values should come from sensor specific
+	 * tuning processes. This is a first rough approximation.
+	 */
+	params->obgrid_param.gr = 64;
+	params->obgrid_param.r  = 64;
+	params->obgrid_param.b  = 64;
+	params->obgrid_param.gb = 64;
+
+	/* Enable the custom black level correction processing */
+	params->use.obgrid = 1;
+	params->use.obgrid_param = 1;
+}
+
+} /* namespace ipa::ipu3::algorithms */
+
+} /* namespace libcamera */