ipa: libipa: Introduce Algorithm class template

The algorithms are using the same function names with specialized
parameters. Instead of duplicating code, introduce a libipa Algorithm
class which implements a base class with template parameters in libipa,
and use it in each IPA.

As we now won't need an algorithm class for each IPA, move the
documentation to libipa, and make it agnostic of the IPA used. While at
it, fix the IPU3::Algorithm::Awb documentation.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>

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 */