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/* SPDX-License-Identifier: BSD-2-Clause */
/*
* Copyright (C) 2019, Raspberry Pi Ltd
*
* md_parser.h - image sensor metadata parser interface
*/
#pragma once
#include <initializer_list>
#include <map>
#include <optional>
#include <stdint.h>
#include <libcamera/base/span.h>
/*
* Camera metadata parser class. Usage as shown below.
*
* Setup:
*
* Usually the metadata parser will be made as part of the CamHelper class so
* 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 MdParserSmia({ expHiReg, expLoReg, gainReg });
* parser->SetBitsPerPixel(bpp);
* parser->SetLineLengthBytes(pitch);
* parser->SetNumLines(2);
*
* Note 1: if you don't know how many lines there are, the size of the input
* buffer is used as a limit instead.
*
* Note 2: if you don't know the line length, you can leave the line length unset
* (or set to zero) and the parser will hunt for the line start instead.
*
* Then on every frame:
*
* RegisterMap registers;
* if (parser->Parse(buffer, registers) != MdParser::OK)
* much badness;
* Metadata metadata;
* CamHelper::PopulateMetadata(registers, metadata);
*
* (Note that the CamHelper class converts to/from exposure lines and time,
* and gain_code / actual gain.)
*
* If you suspect your embedded data may have changed its layout, change any line
* lengths, number of lines, bits per pixel etc. that are different, and
* then:
*
* parser->Reset();
*
* before calling Parse again.
*/
namespace RPiController {
/* Abstract base class from which other metadata parsers are derived. */
class MdParser
{
public:
using RegisterMap = std::map<uint32_t, uint32_t>;
/*
* Parser status codes:
* OK - success
* NOTFOUND - value such as exposure or gain was not found
* ERROR - all other errors
*/
enum Status {
OK = 0,
NOTFOUND = 1,
ERROR = 2
};
MdParser()
: reset_(true), bitsPerPixel_(0), numLines_(0), lineLengthBytes_(0)
{
}
virtual ~MdParser() = default;
void reset()
{
reset_ = true;
}
void setBitsPerPixel(int bpp)
{
bitsPerPixel_ = bpp;
}
void setNumLines(unsigned int numLines)
{
numLines_ = numLines;
}
void setLineLengthBytes(unsigned int numBytes)
{
lineLengthBytes_ = numBytes;
}
virtual Status parse(libcamera::Span<const uint8_t> buffer,
RegisterMap ®isters) = 0;
protected:
bool reset_;
int bitsPerPixel_;
unsigned int numLines_;
unsigned int lineLengthBytes_;
};
/*
* This isn't a full implementation of a metadata parser for SMIA sensors,
* however, it does provide the findRegs function which will prove useful and
* make it easier to implement parsers for other SMIA-like sensors (see
* md_parser_imx219.cpp for an example).
*/
class MdParserSmia final : public MdParser
{
public:
MdParserSmia(std::initializer_list<uint32_t> registerList);
MdParser::Status parse(libcamera::Span<const uint8_t> buffer,
RegisterMap ®isters) override;
private:
/* Maps register address to offset in the buffer. */
using OffsetMap = std::map<uint32_t, std::optional<uint32_t>>;
/*
* Note that error codes > 0 are regarded as non-fatal; codes < 0
* indicate a bad data buffer. Status codes are:
* ParseOk - found all registers, much happiness
* MissingRegs - some registers found; should this be a hard error?
* The remaining codes are all hard errors.
*/
enum ParseStatus {
ParseOk = 0,
MissingRegs = 1,
NoLineStart = -1,
IllegalTag = -2,
BadDummy = -3,
BadLineEnd = -4,
BadPadding = -5
};
ParseStatus findRegs(libcamera::Span<const uint8_t> buffer);
OffsetMap offsets_;
};
} /* namespace RPi */
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