libcamera: ipa: Raspberry Pi IPA

Initial implementation of the Raspberry Pi (BCM2835) libcamera IPA and
associated libraries.

All code is licensed under the BSD-2-Clause terms.
Copyright (c) 2019-2020 Raspberry Pi Trading Ltd.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/ipa/raspberrypi/cam_helper.cpp

@@ -0,0 +1,119 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2019, Raspberry Pi (Trading) Limited
+ *
+ * cam_helper.cpp - helper information for different sensors
+ */
+
+#include <linux/videodev2.h>
+
+#include <assert.h>
+#include <map>
+#include <string.h>
+
+#include "cam_helper.hpp"
+#include "md_parser.hpp"
+
+#include "v4l2_videodevice.h"
+
+using namespace RPi;
+
+static std::map<std::string, CamHelperCreateFunc> cam_helpers;
+
+CamHelper *CamHelper::Create(std::string const &cam_name)
+{
+	/*
+	 * CamHelpers get registered by static RegisterCamHelper
+	 * initialisers.
+	 */
+	for (auto &p : cam_helpers) {
+		if (cam_name.find(p.first) != std::string::npos)
+			return p.second();
+	}
+
+	return nullptr;
+}
+
+CamHelper::CamHelper(MdParser *parser)
+	: parser_(parser), initialized_(false)
+{
+}
+
+CamHelper::~CamHelper()
+{
+	delete parser_;
+}
+
+uint32_t CamHelper::ExposureLines(double exposure_us) const
+{
+	assert(initialized_);
+	return exposure_us * 1000.0 / mode_.line_length;
+}
+
+double CamHelper::Exposure(uint32_t exposure_lines) const
+{
+	assert(initialized_);
+	return exposure_lines * mode_.line_length / 1000.0;
+}
+
+void CamHelper::SetCameraMode(const CameraMode &mode)
+{
+	mode_ = mode;
+	parser_->SetBitsPerPixel(mode.bitdepth);
+	parser_->SetLineLengthBytes(0); /* We use SetBufferSize. */
+	initialized_ = true;
+}
+
+void CamHelper::GetDelays(int &exposure_delay, int &gain_delay) const
+{
+	/*
+	 * These values are correct for many sensors. Other sensors will
+	 * need to over-ride this method.
+	 */
+	exposure_delay = 2;
+	gain_delay = 1;
+}
+
+bool CamHelper::SensorEmbeddedDataPresent() const
+{
+	return false;
+}
+
+unsigned int CamHelper::HideFramesStartup() const
+{
+	/*
+	 * By default, hide 6 frames completely at start-up while AGC etc. sort
+	 * themselves out (converge).
+	 */
+	return 6;
+}
+
+unsigned int CamHelper::HideFramesModeSwitch() const
+{
+	/* After a mode switch, many sensors return valid frames immediately. */
+	return 0;
+}
+
+unsigned int CamHelper::MistrustFramesStartup() const
+{
+	/* Many sensors return a single bad frame on start-up. */
+	return 1;
+}
+
+unsigned int CamHelper::MistrustFramesModeSwitch() const
+{
+	/* Many sensors return valid metadata immediately. */
+	return 0;
+}
+
+CamTransform CamHelper::GetOrientation() const
+{
+	/* Most sensors will be mounted the "right" way up? */
+	return CamTransform_IDENTITY;
+}
+
+RegisterCamHelper::RegisterCamHelper(char const *cam_name,
+				     CamHelperCreateFunc create_func)
+{
+	cam_helpers[std::string(cam_name)] = create_func;
+}