3 files changed, 134 insertions, 0 deletions
diff --git a/src/ipa/libipa/algorithm.cpp b/src/ipa/libipa/algorithm.cpp
new file mode 100644
index 00000000..398d5372
--- /dev/null
+++ b/src/ipa/libipa/algorithm.cpp
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021, Ideas On Board
+ *
+ * algorithm.cpp - IPA control algorithm interface
+ */
+
+#include "algorithm.h"
+
+/**
+ * \file algorithm.h
+ * \brief Algorithm common interface
+ */
+
+namespace libcamera {
+
+namespace ipa {
+
+/**
+ * \class Algorithm
+ * \brief The base class for all IPA algorithms
+ * \tparam Context The type of shared IPA context
+ * \tparam Config The type of the IPA configuration data
+ * \tparam Params The type of the ISP specific parameters
+ * \tparam Stats The type of the IPA statistics and ISP results
+ *
+ * The Algorithm class defines a standard interface for IPA algorithms. By
+ * abstracting algorithms, it makes possible the implementation of generic code
+ * to manage algorithms regardless of their specific type.
+ */
+
+/**
+ * \fn Algorithm::configure()
+ * \brief Configure the Algorithm given an IPAConfigInfo
+ * \param[in] context The shared IPA context
+ * \param[in] configInfo The IPA configuration data, received from the pipeline
+ * handler
+ *
+ * Algorithms may implement a configure operation to pre-calculate
+ * parameters prior to commencing streaming.
+ *
+ * Configuration state may be stored in the IPASessionConfiguration structure of
+ * the IPAContext.
+ *
+ * \return 0 if successful, an error code otherwise
+ */
+
+/**
+ * \fn Algorithm::prepare()
+ * \brief Fill the \a params buffer with ISP processing parameters for a frame
+ * \param[in] context The shared IPA context
+ * \param[out] params The ISP specific parameters.
+ *
+ * This function is called for every frame when the camera is running before it
+ * is processed by the ISP to prepare the ISP processing parameters for that
+ * frame.
+ *
+ * Algorithms shall fill in the parameter structure fields appropriately to
+ * configure the ISP processing blocks that they are responsible for. This
+ * includes setting fields and flags that enable those processing blocks.
+ */
+
+/**
+ * \fn Algorithm::process()
+ * \brief Process ISP statistics, and run algorithm operations
+ * \param[in] context The shared IPA context
+ * \param[in] stats The IPA statistics and ISP results
+ *
+ * This function is called while camera is running for every frame processed by
+ * the ISP, to process statistics generated from that frame by the ISP.
+ * Algorithms shall use this data to run calculations and update their state
+ * accordingly.
+ *
+ * Processing shall not take an undue amount of time, and any extended or
+ * computationally expensive calculations or operations must be handled
+ * asynchronously in a separate thread.
+ *
+ * Algorithms can store state in their respective IPAFrameContext structures,
+ * and reference state from the IPAFrameContext of other algorithms.
+ *
+ * \todo Historical data may be required as part of the processing.
+ * Either the previous frame, or the IPAFrameContext state of the frame
+ * that generated the statistics for this operation may be required for
+ * some advanced algorithms to prevent oscillations or support control
+ * loops correctly. Only a single IPAFrameContext is available currently,
+ * and so any data stored may represent the results of the previously
+ * completed operations.
+ *
+ * Care shall be taken to ensure the ordering of access to the information
+ * such that the algorithms use up to date state as required.
+ */
+
+} /* namespace ipa */
+
+} /* namespace libcamera */
diff --git a/src/ipa/libipa/algorithm.h b/src/ipa/libipa/algorithm.h
new file mode 100644
index 00000000..766aee5d
--- /dev/null
+++ b/src/ipa/libipa/algorithm.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021, Ideas On Board
+ *
+ * algorithm.h - ISP control algorithm interface
+ */
+#pragma once
+
+namespace libcamera {
+
+namespace ipa {
+
+template<typename Context, typename Config, typename Params, typename Stats>
+class Algorithm
+{
+public:
+	virtual ~Algorithm() {}
+
+	virtual int configure([[maybe_unused]] Context &context,
+			      [[maybe_unused]] const Config &configInfo)
+	{
+		return 0;
+	}
+
+	virtual void prepare([[maybe_unused]] Context &context,
+			     [[maybe_unused]] Params *params)
+	{
+	}
+
+	virtual void process([[maybe_unused]] Context &context,
+			     [[maybe_unused]] const Stats *stats)
+	{
+	}
+};
+
+} /* namespace ipa */
+
+} /* namespace libcamera */
diff --git a/src/ipa/libipa/meson.build b/src/ipa/libipa/meson.build
index 4d073a03..161cc5a1 100644
--- a/src/ipa/libipa/meson.build
+++ b/src/ipa/libipa/meson.build
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: CC0-1.0
 
 libipa_headers = files([
+    'algorithm.h',
     'camera_sensor_helper.h',
     'histogram.h'
 ])