[libcamera-devel] [PATCH v2] ipa: rpi: imx296: Enable embedded data

[Naushir Patuck]

Enable embedded data parsing for the imx296 sensor.

However, the imx296 has a quirk where the embedded data is ahead by a
single frame, i.e. embedded data in frame N corresponds to the image
data in frame N+1. So make a copy of the embedded data buffer stored in
the camera helper state, and use that copy in the next frame.

Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
---
Changes since v1:
- Replace the use of std::unique_ptr with std::vector<uint8_t>
---
 src/ipa/rpi/cam_helper/cam_helper_imx296.cpp | 60 +++++++++++++++++++-
 1 file changed, 59 insertions(+), 1 deletion(-)

diff --git a/src/ipa/rpi/cam_helper/cam_helper_imx296.cpp b/src/ipa/rpi/cam_helper/cam_helper_imx296.cpp
index ecb845e76e12..e84243704e5a 100644
--- a/src/ipa/rpi/cam_helper/cam_helper_imx296.cpp
+++ b/src/ipa/rpi/cam_helper/cam_helper_imx296.cpp
@@ -7,7 +7,9 @@
 
 #include <algorithm>
 #include <cmath>
+#include <string.h>
 #include <stddef.h>
+#include <vector>
 
 #include "cam_helper.h"
 
@@ -15,6 +17,17 @@ using namespace RPiController;
 using libcamera::utils::Duration;
 using namespace std::literals::chrono_literals;
 
+constexpr uint32_t gainReg = 0x41ba;
+constexpr uint32_t shsLoReg = 0x41b4;
+constexpr uint32_t shsMidReg = 0x41b5;
+constexpr uint32_t shsHiReg = 0x41b6;
+constexpr uint32_t vmaxLoReg = 0x41cc;
+constexpr uint32_t vmaxMidReg = 0x41cd;
+constexpr uint32_t vmaxHiReg = 0x41ce;
+constexpr uint32_t tempReg = 0x41da;
+constexpr std::initializer_list<uint32_t> registerList =
+	{ gainReg, shsLoReg, shsMidReg, shsHiReg, vmaxLoReg, vmaxMidReg, vmaxHiReg, tempReg };
+
 class CamHelperImx296 : public CamHelper
 {
 public:
@@ -23,8 +36,12 @@ public:
 	double gain(uint32_t gainCode) const override;
 	uint32_t exposureLines(const Duration exposure, const Duration lineLength) const override;
 	Duration exposure(uint32_t exposureLines, const Duration lineLength) const override;
+	void prepare(libcamera::Span<const uint8_t> buffer, Metadata &metadata) override;
 	void getDelays(int &exposureDelay, int &gainDelay,
 		       int &vblankDelay, int &hblankDelay) const override;
+	bool sensorEmbeddedDataPresent() const override;
+	void populateMetadata(const MdParser::RegisterMap &registers,
+			      Metadata &metadata) const override;
 
 private:
 	static constexpr uint32_t minExposureLines = 1;
@@ -36,10 +53,12 @@ private:
 	 * in units of lines.
 	 */
 	static constexpr int frameIntegrationDiff = 4;
+
+	std::vector<uint8_t> lastEmbeddedBuffer_;
 };
 
 CamHelperImx296::CamHelperImx296()
-	: CamHelper(nullptr, frameIntegrationDiff)
+	: CamHelper(std::make_unique<MdParserSmia>(registerList), frameIntegrationDiff)
 {
 }
 
@@ -66,6 +85,23 @@ Duration CamHelperImx296::exposure(uint32_t exposureLines,
 	return std::max<uint32_t>(minExposureLines, exposureLines) * timePerLine + 14.26us;
 }
 
+void CamHelperImx296::prepare(libcamera::Span<const uint8_t> buffer, Metadata &metadata)
+{
+	/*
+	 * The imx296 embedded data is ahead by a single frame, i.e. embedded
+	 * data in frame N corresponds to the image data in frame N+1. So make
+	 * a copy of the embedded data buffer and use it as normal for the next
+	 * frame.
+	 */
+	CamHelper::prepare({ lastEmbeddedBuffer_.data(), lastEmbeddedBuffer_.size() },
+			   metadata);
+
+	if (lastEmbeddedBuffer_.size() != buffer.size())
+		lastEmbeddedBuffer_.resize(buffer.size());
+
+	memcpy(lastEmbeddedBuffer_.data(), buffer.data(), buffer.size());
+}
+
 void CamHelperImx296::getDelays(int &exposureDelay, int &gainDelay,
 				int &vblankDelay, int &hblankDelay) const
 {
@@ -75,6 +111,28 @@ void CamHelperImx296::getDelays(int &exposureDelay, int &gainDelay,
 	hblankDelay = 2;
 }
 
+bool CamHelperImx296::sensorEmbeddedDataPresent() const
+{
+	return true;
+}
+
+void CamHelperImx296::populateMetadata(const MdParser::RegisterMap &registers,
+				       Metadata &metadata) const
+{
+	uint32_t shs = registers.at(shsLoReg) + (registers.at(shsMidReg) << 8) +
+		       (registers.at(shsHiReg) << 16);
+	uint32_t vmax = registers.at(vmaxLoReg) + (registers.at(vmaxMidReg) << 8) +
+			(registers.at(vmaxHiReg) << 16);
+
+	DeviceStatus deviceStatus;
+	deviceStatus.lineLength = timePerLine;
+	deviceStatus.frameLength = vmax;
+	deviceStatus.shutterSpeed = exposure(vmax - shs, timePerLine);
+	deviceStatus.analogueGain = gain(registers.at(gainReg));
+
+	metadata.set("device.status", deviceStatus);
+}
+
 static CamHelper *create()
 {
 	return new CamHelperImx296();
-- 
2.34.1