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_imx219.cpp

@@ -0,0 +1,180 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2019, Raspberry Pi (Trading) Limited
+ *
+ * cam_helper_imx219.cpp - camera helper for imx219 sensor
+ */
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/*
+ * We have observed the imx219 embedded data stream randomly return junk
+ * reister values.  Do not rely on embedded data until this has been resolved.
+ */
+#define ENABLE_EMBEDDED_DATA 0
+
+#include "cam_helper.hpp"
+#if ENABLE_EMBEDDED_DATA
+#include "md_parser.hpp"
+#else
+#include "md_parser_rpi.hpp"
+#endif
+
+using namespace RPi;
+
+/* Metadata parser implementation specific to Sony IMX219 sensors. */
+
+class MdParserImx219 : public MdParserSmia
+{
+public:
+	MdParserImx219();
+	Status Parse(void *data) override;
+	Status GetExposureLines(unsigned int &lines) override;
+	Status GetGainCode(unsigned int &gain_code) override;
+private:
+	/* Offset of the register's value in the metadata block. */
+	int reg_offsets_[3];
+	/* Value of the register, once read from the metadata block. */
+	int reg_values_[3];
+};
+
+class CamHelperImx219 : public CamHelper
+{
+public:
+	CamHelperImx219();
+	uint32_t GainCode(double gain) const override;
+	double Gain(uint32_t gain_code) const override;
+	unsigned int MistrustFramesModeSwitch() const override;
+	bool SensorEmbeddedDataPresent() const override;
+	CamTransform GetOrientation() const override;
+};
+
+CamHelperImx219::CamHelperImx219()
+#if ENABLE_EMBEDDED_DATA
+	: CamHelper(new MdParserImx219())
+#else
+	: CamHelper(new MdParserRPi())
+#endif
+{
+}
+
+uint32_t CamHelperImx219::GainCode(double gain) const
+{
+	return (uint32_t)(256 - 256 / gain);
+}
+
+double CamHelperImx219::Gain(uint32_t gain_code) const
+{
+	return 256.0 / (256 - gain_code);
+}
+
+unsigned int CamHelperImx219::MistrustFramesModeSwitch() const
+{
+	/*
+	 * For reasons unknown, we do occasionally get a bogus metadata frame
+	 * at a mode switch (though not at start-up). Possibly warrants some
+	 * investigation, though not a big deal.
+	 */
+	return 1;
+}
+
+bool CamHelperImx219::SensorEmbeddedDataPresent() const
+{
+	return ENABLE_EMBEDDED_DATA;
+}
+
+CamTransform CamHelperImx219::GetOrientation() const
+{
+	/* Camera is "upside down" on this board. */
+	return CamTransform_HFLIP | CamTransform_VFLIP;
+}
+
+static CamHelper *Create()
+{
+	return new CamHelperImx219();
+}
+
+static RegisterCamHelper reg("imx219", &Create);
+
+/*
+ * We care about one gain register and a pair of exposure registers. Their I2C
+ * addresses from the Sony IMX219 datasheet:
+ */
+#define GAIN_REG 0x157
+#define EXPHI_REG 0x15A
+#define EXPLO_REG 0x15B
+
+/*
+ * Index of each into the reg_offsets and reg_values arrays. Must be in
+ * register address order.
+ */
+#define GAIN_INDEX 0
+#define EXPHI_INDEX 1
+#define EXPLO_INDEX 2
+
+MdParserImx219::MdParserImx219()
+{
+	reg_offsets_[0] = reg_offsets_[1] = reg_offsets_[2] = -1;
+}
+
+MdParser::Status MdParserImx219::Parse(void *data)
+{
+	bool try_again = false;
+
+	if (reset_) {
+		/*
+		 * Search again through the metadata for the gain and exposure
+		 * registers.
+		 */
+		assert(bits_per_pixel_);
+		assert(num_lines_ || buffer_size_bytes_);
+		/* Need to be ordered */
+		uint32_t regs[3] = { GAIN_REG, EXPHI_REG, EXPLO_REG };
+		reg_offsets_[0] = reg_offsets_[1] = reg_offsets_[2] = -1;
+		int ret = static_cast<int>(findRegs(static_cast<uint8_t *>(data),
+						    regs, reg_offsets_, 3));
+		/*
+		 * > 0 means "worked partially but parse again next time",
+		 * < 0 means "hard error".
+		 */
+		if (ret > 0)
+			try_again = true;
+		else if (ret < 0)
+			return ERROR;
+	}
+
+	for (int i = 0; i < 3; i++) {
+		if (reg_offsets_[i] == -1)
+			continue;
+
+		reg_values_[i] = static_cast<uint8_t *>(data)[reg_offsets_[i]];
+	}
+
+	/* Re-parse next time if we were unhappy in some way. */
+	reset_ = try_again;
+
+	return OK;
+}
+
+MdParser::Status MdParserImx219::GetExposureLines(unsigned int &lines)
+{
+	if (reg_offsets_[EXPHI_INDEX] == -1 || reg_offsets_[EXPLO_INDEX] == -1)
+		return NOTFOUND;
+
+	lines = reg_values_[EXPHI_INDEX] * 256 + reg_values_[EXPLO_INDEX];
+
+	return OK;
+}
+
+MdParser::Status MdParserImx219::GetGainCode(unsigned int &gain_code)
+{
+	if (reg_offsets_[GAIN_INDEX] == -1)
+		return NOTFOUND;
+
+	gain_code = reg_values_[GAIN_INDEX];
+
+	return OK;
+}