ipa: raspberrypi: Generalise the SMIA metadata parser

Instead of having each CamHelper subclass the MdParserSmia, change the
implementation of MdParserSmia to be more generic. The MdParserSmia now gets
given a list of registers to search for and helper functions are used to compute
exposure lines and gain codes from these registers.

Update the imx219 and imx477 CamHelpers by using this new mechanism.

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

6 files changed, 144 insertions, 235 deletions

diff --git a/src/ipa/raspberrypi/cam_helper.cpp b/src/ipa/raspberrypi/cam_helper.cpp
index 90498c37..e6d2258c 100644
--- a/src/ipa/raspberrypi/cam_helper.cpp
+++ b/src/ipa/raspberrypi/cam_helper.cpp
@@ -159,32 +159,34 @@ unsigned int CamHelper::MistrustFramesModeSwitch() const
 void CamHelper::parseEmbeddedData(Span<const uint8_t> buffer,
 				  Metadata &metadata)
 {
+	MdParser::RegisterMap registers;
+	Metadata parsedMetadata;
+
 	if (buffer.empty())
 		return;
 
-	uint32_t exposureLines, gainCode;
-
-	if (parser_->Parse(buffer) != MdParser::Status::OK ||
-	    parser_->GetExposureLines(exposureLines) != MdParser::Status::OK ||
-	    parser_->GetGainCode(gainCode) != MdParser::Status::OK) {
+	if (parser_->Parse(buffer, registers) != MdParser::Status::OK) {
 		LOG(IPARPI, Error) << "Embedded data buffer parsing failed";
 		return;
 	}
 
+	PopulateMetadata(registers, parsedMetadata);
+	metadata.Merge(parsedMetadata);
+
 	/*
-	 * Overwrite the exposure/gain values in the DeviceStatus, as
-	 * we know better. Fetch it first in case any other fields were
-	 * set meaningfully.
+	 * Overwrite the exposure/gain values in the existing DeviceStatus with
+	 * values from the parsed embedded buffer. Fetch it first in case any
+	 * other fields were set meaningfully.
 	 */
-	DeviceStatus deviceStatus;
-
-	if (metadata.Get("device.status", deviceStatus) != 0) {
+	DeviceStatus deviceStatus, parsedDeviceStatus;
+	if (metadata.Get("device.status", deviceStatus) ||
+	    parsedMetadata.Get("device.status", parsedDeviceStatus)) {
 		LOG(IPARPI, Error) << "DeviceStatus not found";
 		return;
 	}
 
-	deviceStatus.shutter_speed = Exposure(exposureLines);
-	deviceStatus.analogue_gain = Gain(gainCode);
+	deviceStatus.shutter_speed = parsedDeviceStatus.shutter_speed;
+	deviceStatus.analogue_gain = parsedDeviceStatus.analogue_gain;
 
 	LOG(IPARPI, Debug) << "Metadata updated - Exposure : "
 			   << deviceStatus.shutter_speed
@@ -194,6 +196,11 @@ void CamHelper::parseEmbeddedData(Span<const uint8_t> buffer,
 	metadata.Set("device.status", deviceStatus);
 }
 
+void CamHelper::PopulateMetadata([[maybe_unused]] const MdParser::RegisterMap &registers,
+				 [[maybe_unused]] Metadata &metadata) const
+{
+}
+
 RegisterCamHelper::RegisterCamHelper(char const *cam_name,
 				     CamHelperCreateFunc create_func)
 {
diff --git a/src/ipa/raspberrypi/cam_helper.hpp b/src/ipa/raspberrypi/cam_helper.hpp
index fc3139e2..200cc83f 100644
--- a/src/ipa/raspberrypi/cam_helper.hpp
+++ b/src/ipa/raspberrypi/cam_helper.hpp
@@ -92,6 +92,8 @@ public:
 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_;
diff --git a/src/ipa/raspberrypi/cam_helper_imx219.cpp b/src/ipa/raspberrypi/cam_helper_imx219.cpp
index c85044a5..4d68e01f 100644
--- a/src/ipa/raspberrypi/cam_helper_imx219.cpp
+++ b/src/ipa/raspberrypi/cam_helper_imx219.cpp
@@ -23,21 +23,14 @@
 
 using namespace RPiController;
 
-/* Metadata parser implementation specific to Sony IMX219 sensors. */
-
-class MdParserImx219 : public MdParserSmia
-{
-public:
-	MdParserImx219();
-	Status Parse(libcamera::Span<const uint8_t> buffer) 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];
-};
+/*
+ * We care about one gain register and a pair of exposure registers. Their I2C
+ * addresses from the Sony IMX219 datasheet:
+ */
+constexpr uint32_t gainReg = 0x157;
+constexpr uint32_t expHiReg = 0x15a;
+constexpr uint32_t expLoReg = 0x15b;
+constexpr std::initializer_list<uint32_t> registerList [[maybe_unused]] = { expHiReg, expLoReg, gainReg };
 
 class CamHelperImx219 : public CamHelper
 {
@@ -54,11 +47,14 @@ private:
 	 * in units of lines.
 	 */
 	static constexpr int frameIntegrationDiff = 4;
+
+	void PopulateMetadata(const MdParser::RegisterMap &registers,
+			      Metadata &metadata) const override;
 };
 
 CamHelperImx219::CamHelperImx219()
 #if ENABLE_EMBEDDED_DATA
-	: CamHelper(std::make_unique<MdParserImx219>(), frameIntegrationDiff)
+	: CamHelper(std::make_unique<MdParserSmia>(registerList), frameIntegrationDiff)
 #else
 	: CamHelper({}, frameIntegrationDiff)
 #endif
@@ -90,88 +86,20 @@ bool CamHelperImx219::SensorEmbeddedDataPresent() const
 	return ENABLE_EMBEDDED_DATA;
 }
 
-static CamHelper *Create()
+void CamHelperImx219::PopulateMetadata(const MdParser::RegisterMap &registers,
+				       Metadata &metadata) const
 {
-	return new CamHelperImx219();
-}
+	DeviceStatus deviceStatus;
 
-static RegisterCamHelper reg("imx219", &Create);
+	deviceStatus.shutter_speed = Exposure(registers.at(expHiReg) * 256 + registers.at(expLoReg));
+	deviceStatus.analogue_gain = Gain(registers.at(gainReg));
 
-/*
- * 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;
+	metadata.Set("device.status", deviceStatus);
 }
 
-MdParser::Status MdParserImx219::Parse(libcamera::Span<const uint8_t> buffer)
-{
-	bool try_again = false;
-
-	if (reset_) {
-		/*
-		 * Search again through the metadata for the gain and exposure
-		 * registers.
-		 */
-		assert(bits_per_pixel_);
-		/* 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(buffer,
-						    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] = buffer[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)
+static CamHelper *Create()
 {
-	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;
+	return new CamHelperImx219();
 }
 
-MdParser::Status MdParserImx219::GetGainCode(unsigned int &gain_code)
-{
-	if (reg_offsets_[GAIN_INDEX] == -1)
-		return NOTFOUND;
-
-	gain_code = reg_values_[GAIN_INDEX];
-
-	return OK;
-}
+static RegisterCamHelper reg("imx219", &Create);
diff --git a/src/ipa/raspberrypi/cam_helper_imx477.cpp b/src/ipa/raspberrypi/cam_helper_imx477.cpp
index d72a9be0..4098fde6 100644
--- a/src/ipa/raspberrypi/cam_helper_imx477.cpp
+++ b/src/ipa/raspberrypi/cam_helper_imx477.cpp
@@ -15,21 +15,15 @@
 
 using namespace RPiController;
 
-/* Metadata parser implementation specific to Sony IMX477 sensors. */
-
-class MdParserImx477 : public MdParserSmia
-{
-public:
-	MdParserImx477();
-	Status Parse(libcamera::Span<const uint8_t> buffer) 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_[4];
-	/* Value of the register, once read from the metadata block. */
-	int reg_values_[4];
-};
+/*
+ * We care about two gain registers and a pair of exposure registers. Their
+ * I2C addresses from the Sony IMX477 datasheet:
+ */
+constexpr uint32_t expHiReg = 0x0202;
+constexpr uint32_t expLoReg = 0x0203;
+constexpr uint32_t gainHiReg = 0x0204;
+constexpr uint32_t gainLoReg = 0x0205;
+constexpr std::initializer_list<uint32_t> registerList [[maybe_unused]] = { expHiReg, expLoReg, gainHiReg, gainLoReg };
 
 class CamHelperImx477 : public CamHelper
 {
@@ -47,10 +41,13 @@ private:
 	 * in units of lines.
 	 */
 	static constexpr int frameIntegrationDiff = 22;
+
+	void PopulateMetadata(const MdParser::RegisterMap &registers,
+			      Metadata &metadata) const override;
 };
 
 CamHelperImx477::CamHelperImx477()
-	: CamHelper(std::make_unique<MdParserImx477>(), frameIntegrationDiff)
+	: CamHelper(std::make_unique<MdParserSmia>(registerList), frameIntegrationDiff)
 {
 }
 
@@ -77,95 +74,20 @@ bool CamHelperImx477::SensorEmbeddedDataPresent() const
 	return true;
 }
 
-static CamHelper *Create()
+void CamHelperImx477::PopulateMetadata(const MdParser::RegisterMap &registers,
+				       Metadata &metadata) const
 {
-	return new CamHelperImx477();
-}
+	DeviceStatus deviceStatus;
 
-static RegisterCamHelper reg("imx477", &Create);
+	deviceStatus.shutter_speed = Exposure(registers.at(expHiReg) * 256 + registers.at(expLoReg));
+	deviceStatus.analogue_gain = Gain(registers.at(gainHiReg) * 256 + registers.at(gainLoReg));
 
-/*
- * We care about two gain registers and a pair of exposure registers. Their
- * I2C addresses from the Sony IMX477 datasheet:
- */
-#define EXPHI_REG 0x0202
-#define EXPLO_REG 0x0203
-#define GAINHI_REG 0x0204
-#define GAINLO_REG 0x0205
-
-/*
- * Index of each into the reg_offsets and reg_values arrays. Must be in register
- * address order.
- */
-#define EXPHI_INDEX 0
-#define EXPLO_INDEX 1
-#define GAINHI_INDEX 2
-#define GAINLO_INDEX 3
-
-MdParserImx477::MdParserImx477()
-{
-	reg_offsets_[0] = reg_offsets_[1] = reg_offsets_[2] = reg_offsets_[3] = -1;
+	metadata.Set("device.status", deviceStatus);
 }
 
-MdParser::Status MdParserImx477::Parse(libcamera::Span<const uint8_t> buffer)
-{
-	bool try_again = false;
-
-	if (reset_) {
-		/*
-		 * Search again through the metadata for the gain and exposure
-		 * registers.
-		 */
-		assert(bits_per_pixel_);
-		/* Need to be ordered */
-		uint32_t regs[4] = {
-			EXPHI_REG,
-			EXPLO_REG,
-			GAINHI_REG,
-			GAINLO_REG
-		};
-		reg_offsets_[0] = reg_offsets_[1] = reg_offsets_[2] = reg_offsets_[3] = -1;
-		int ret = static_cast<int>(findRegs(buffer,
-						    regs, reg_offsets_, 4));
-		/*
-		 * > 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 < 4; i++) {
-		if (reg_offsets_[i] == -1)
-			continue;
-
-		reg_values_[i] = buffer[reg_offsets_[i]];
-	}
-
-	/* Re-parse next time if we were unhappy in some way. */
-	reset_ = try_again;
-
-	return OK;
-}
-
-MdParser::Status MdParserImx477::GetExposureLines(unsigned int &lines)
+static CamHelper *Create()
 {
-	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;
+	return new CamHelperImx477();
 }
 
-MdParser::Status MdParserImx477::GetGainCode(unsigned int &gain_code)
-{
-	if (reg_offsets_[GAINHI_INDEX] == -1 || reg_offsets_[GAINLO_INDEX] == -1)
-		return NOTFOUND;
-
-	gain_code = reg_values_[GAINHI_INDEX] * 256 + reg_values_[GAINLO_INDEX];
-
-	return OK;
-}
+static RegisterCamHelper reg("imx477", &Create);
diff --git a/src/ipa/raspberrypi/md_parser.hpp b/src/ipa/raspberrypi/md_parser.hpp
index 8497216f..e3e27385 100644
--- a/src/ipa/raspberrypi/md_parser.hpp
+++ b/src/ipa/raspberrypi/md_parser.hpp
@@ -6,6 +6,9 @@
  */
 #pragma once
 
+#include <initializer_list>
+#include <map>
+#include <optional>
 #include <stdint.h>
 
 #include <libcamera/base/span.h>
@@ -19,7 +22,7 @@
  * application code doesn't have to worry which kind to instantiate. But for
  * the sake of example let's suppose we're parsing imx219 metadata.
  *
- * MdParser *parser = new MdParserImx219();  // for example
+ * MdParser *parser = new MdParserSmia({ expHiReg, expLoReg, gainReg });
  * parser->SetBitsPerPixel(bpp);
  * parser->SetLineLengthBytes(pitch);
  * parser->SetNumLines(2);
@@ -32,13 +35,11 @@
  *
  * Then on every frame:
  *
- * if (parser->Parse(buffer) != MdParser::OK)
+ * RegisterMap registers;
+ * if (parser->Parse(buffer, registers) != MdParser::OK)
  *     much badness;
- * unsigned int exposure_lines, gain_code
- * if (parser->GetExposureLines(exposure_lines) != MdParser::OK)
- *     exposure was not found;
- * if (parser->GetGainCode(parser, gain_code) != MdParser::OK)
- *     gain code was not found;
+ * Metadata metadata;
+ * CamHelper::PopulateMetadata(registers, metadata);
  *
  * (Note that the CamHelper class converts to/from exposure lines and time,
  * and gain_code / actual gain.)
@@ -59,6 +60,8 @@ namespace RPiController {
 class MdParser
 {
 public:
+	using RegisterMap = std::map<uint32_t, uint32_t>;
+
 	/*
 	 * Parser status codes:
 	 * OK       - success
@@ -98,9 +101,8 @@ public:
 		line_length_bytes_ = num_bytes;
 	}
 
-	virtual Status Parse(libcamera::Span<const uint8_t> buffer) = 0;
-	virtual Status GetExposureLines(unsigned int &lines) = 0;
-	virtual Status GetGainCode(unsigned int &gain_code) = 0;
+	virtual Status Parse(libcamera::Span<const uint8_t> buffer,
+			     RegisterMap &registers) = 0;
 
 protected:
 	bool reset_;
@@ -116,14 +118,18 @@ protected:
  * md_parser_imx219.cpp for an example).
  */
 
-class MdParserSmia : public MdParser
+class MdParserSmia final : public MdParser
 {
 public:
-	MdParserSmia() : MdParser()
-	{
-	}
+	MdParserSmia(std::initializer_list<uint32_t> registerList);
+
+	MdParser::Status Parse(libcamera::Span<const uint8_t> buffer,
+			       RegisterMap &registers) override;
+
+private:
+	/* Maps register address to offset in the buffer. */
+	using OffsetMap = std::map<uint32_t, std::optional<uint32_t>>;
 
-protected:
 	/*
 	 * Note that error codes > 0 are regarded as non-fatal; codes < 0
 	 * indicate a bad data buffer. Status codes are:
@@ -141,8 +147,9 @@ protected:
 		BAD_PADDING   = -5
 	};
 
-	ParseStatus findRegs(libcamera::Span<const uint8_t> buffer, uint32_t regs[],
-			     int offsets[], unsigned int num_regs);
+	ParseStatus findRegs(libcamera::Span<const uint8_t> buffer);
+
+	OffsetMap offsets_;
 };
 
 } // namespace RPi
diff --git a/src/ipa/raspberrypi/md_parser_smia.cpp b/src/ipa/raspberrypi/md_parser_smia.cpp
index 0a148755..ea5eac41 100644
--- a/src/ipa/raspberrypi/md_parser_smia.cpp
+++ b/src/ipa/raspberrypi/md_parser_smia.cpp
@@ -4,11 +4,12 @@
  *
  * md_parser_smia.cpp - SMIA specification based embedded data parser
  */
-#include <assert.h>
 
+#include <libcamera/base/log.h>
 #include "md_parser.hpp"
 
 using namespace RPiController;
+using namespace libcamera;
 
 /*
  * This function goes through the embedded data to find the offsets (not
@@ -26,18 +27,61 @@ constexpr unsigned int REG_LOW_BITS = 0xa5;
 constexpr unsigned int REG_VALUE = 0x5a;
 constexpr unsigned int REG_SKIP = 0x55;
 
-MdParserSmia::ParseStatus MdParserSmia::findRegs(libcamera::Span<const uint8_t> buffer,
-						 uint32_t regs[], int offsets[],
-						 unsigned int num_regs)
+MdParserSmia::MdParserSmia(std::initializer_list<uint32_t> registerList)
 {
-	assert(num_regs > 0);
+	for (auto r : registerList)
+		offsets_[r] = {};
+}
+
+MdParser::Status MdParserSmia::Parse(libcamera::Span<const uint8_t> buffer,
+				     RegisterMap &registers)
+{
+	if (reset_) {
+		/*
+		 * Search again through the metadata for all the registers
+		 * requested.
+		 */
+		ASSERT(bits_per_pixel_);
+
+		for (const auto &kv : offsets_)
+			offsets_[kv.first] = {};
+
+		ParseStatus ret = findRegs(buffer);
+		/*
+		 * > 0 means "worked partially but parse again next time",
+		 * < 0 means "hard error".
+		 *
+		 * In either case, we retry parsing on the next frame.
+		 */
+		if (ret != PARSE_OK)
+			return ERROR;
+
+		reset_ = false;
+	}
+
+	/* Populate the register values requested. */
+	registers.clear();
+	for (const auto &[reg, offset] : offsets_) {
+		if (!offset) {
+			reset_ = true;
+			return NOTFOUND;
+		}
+		registers[reg] = buffer[offset.value()];
+	}
+
+	return OK;
+}
+
+MdParserSmia::ParseStatus MdParserSmia::findRegs(libcamera::Span<const uint8_t> buffer)
+{
+	ASSERT(offsets_.size());
 
 	if (buffer[0] != LINE_START)
 		return NO_LINE_START;
 
 	unsigned int current_offset = 1; /* after the LINE_START */
 	unsigned int current_line_start = 0, current_line = 0;
-	unsigned int reg_num = 0, first_reg = 0;
+	unsigned int reg_num = 0, regs_done = 0;
 
 	while (1) {
 		int tag = buffer[current_offset++];
@@ -89,13 +133,12 @@ MdParserSmia::ParseStatus MdParserSmia::findRegs(libcamera::Span<const uint8_t>
 			else if (tag == REG_SKIP)
 				reg_num++;
 			else if (tag == REG_VALUE) {
-				while (reg_num >=
-				       /* assumes registers are in order... */
-				       regs[first_reg]) {
-					if (reg_num == regs[first_reg])
-						offsets[first_reg] = current_offset - 1;
+				auto reg = offsets_.find(reg_num);
+
+				if (reg != offsets_.end()) {
+					offsets_[reg_num] = current_offset - 1;
 
-					if (++first_reg == num_regs)
+					if (++regs_done == offsets_.size())
 						return PARSE_OK;
 				}
 				reg_num++;