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+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2019, Raspberry Pi (Trading) Limited
+ *
+ * cam_helper.h - helper class providing camera information
+ */
+#pragma once
+
+#include <memory>
+#include <string>
+
+#include <libcamera/base/span.h>
+#include <libcamera/base/utils.h>
+
+#include "camera_mode.h"
+#include "controller/controller.h"
+#include "controller/metadata.h"
+#include "md_parser.h"
+
+#include "libcamera/internal/v4l2_videodevice.h"
+
+namespace RPiController {
+
+/*
+ * The CamHelper class provides a number of facilities that anyone trying
+ * to drive a camera will need to know, but which are not provided by the
+ * standard driver framework. Specifically, it provides:
+ *
+ * A "CameraMode" structure to describe extra information about the chosen
+ * mode of the driver. For example, how it is cropped from the full sensor
+ * area, how it is scaled, whether pixels are averaged compared to the full
+ * resolution.
+ *
+ * The ability to convert between number of lines of exposure and actual
+ * exposure time, and to convert between the sensor's gain codes and actual
+ * gains.
+ *
+ * A function to return the number of frames of delay between updating exposure,
+ * analogue gain and vblanking, and for the changes to take effect. For many
+ * sensors these take the values 2, 1 and 2 respectively, but sensors that are
+ * different will need to over-ride the default function provided.
+ *
+ * A function to query if the sensor outputs embedded data that can be parsed.
+ *
+ * A function to return the sensitivity of a given camera mode.
+ *
+ * A parser to parse the embedded data buffers provided by some sensors (for
+ * example, the imx219 does; the ov5647 doesn't). This allows us to know for
+ * sure the exposure and gain of the frame we're looking at. CamHelper
+ * provides functions for converting analogue gains to and from the sensor's
+ * native gain codes.
+ *
+ * Finally, a set of functions that determine how to handle the vagaries of
+ * different camera modules on start-up or when switching modes. Some
+ * modules may produce one or more frames that are not yet correctly exposed,
+ * or where the metadata may be suspect. We have the following functions:
+ * HideFramesStartup(): Tell the pipeline handler not to return this many
+ * frames at start-up. This can also be used to hide initial frames
+ * while the AGC and other algorithms are sorting themselves out.
+ * HideFramesModeSwitch(): Tell the pipeline handler not to return this
+ * many frames after a mode switch (other than start-up). Some sensors
+ * may produce innvalid frames after a mode switch; others may not.
+ * MistrustFramesStartup(): At start-up a sensor may return frames for
+ * which we should not run any control algorithms (for example, metadata
+ * may be invalid).
+ * MistrustFramesModeSwitch(): The number of frames, after a mode switch
+ * (other than start-up), for which control algorithms should not run
+ * (for example, metadata may be unreliable).
+ */
+
+class CamHelper
+{
+public:
+ static CamHelper *create(std::string const &camName);
+ CamHelper(std::unique_ptr<MdParser> parser, unsigned int frameIntegrationDiff);
+ virtual ~CamHelper();
+ void setCameraMode(const CameraMode &mode);
+ virtual void prepare(libcamera::Span<const uint8_t> buffer,
+ Metadata &metadata);
+ virtual void process(StatisticsPtr &stats, Metadata &metadata);
+ virtual uint32_t exposureLines(libcamera::utils::Duration exposure) const;
+ virtual libcamera::utils::Duration exposure(uint32_t exposureLines) const;
+ virtual uint32_t getVBlanking(libcamera::utils::Duration &exposure,
+ libcamera::utils::Duration minFrameDuration,
+ libcamera::utils::Duration maxFrameDuration) const;
+ virtual uint32_t gainCode(double gain) const = 0;
+ virtual double gain(uint32_t gainCode) const = 0;
+ virtual void getDelays(int &exposureDelay, int &gainDelay,
+ int &vblankDelay) const;
+ virtual bool sensorEmbeddedDataPresent() const;
+ virtual double getModeSensitivity(const CameraMode &mode) const;
+ virtual unsigned int hideFramesStartup() const;
+ virtual unsigned int hideFramesModeSwitch() const;
+ virtual unsigned int mistrustFramesStartup() const;
+ virtual unsigned int mistrustFramesModeSwitch() const;
+
+protected:
+ void parseEmbeddedData(libcamera::Span<const uint8_t> buffer,
+ Metadata &metadata);
+ virtual void populateMetadata(const MdParser::RegisterMap &registers,
+ Metadata &metadata) const;
+
+ std::unique_ptr<MdParser> parser_;
+ CameraMode mode_;
+
+private:
+ bool initialized_;
+ /*
+ * Smallest difference between the frame length and integration time,
+ * in units of lines.
+ */
+ unsigned int frameIntegrationDiff_;
+};
+
+/*
+ * This is for registering camera helpers with the system, so that the
+ * CamHelper::Create function picks them up automatically.
+ */
+
+typedef CamHelper *(*CamHelperCreateFunc)();
+struct RegisterCamHelper
+{
+ RegisterCamHelper(char const *camName,
+ CamHelperCreateFunc createFunc);
+};
+
+} /* namespace RPi */