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/* SPDX-License-Identifier: BSD-2-Clause */
/*
* Copyright (C) 2019-2021, Raspberry Pi Ltd
*
* md_parser_smia.cpp - SMIA specification based embedded data parser
*/
#include <libcamera/base/log.h>
#include "md_parser.h"
using namespace RPiController;
using namespace libcamera;
/*
* This function goes through the embedded data to find the offsets (not
* values!), in the data block, where the values of the given registers can
* subsequently be found.
*
* Embedded data tag bytes, from Sony IMX219 datasheet but general to all SMIA
* sensors, I think.
*/
constexpr unsigned int LineStart = 0x0a;
constexpr unsigned int LineEndTag = 0x07;
constexpr unsigned int RegHiBits = 0xaa;
constexpr unsigned int RegLowBits = 0xa5;
constexpr unsigned int RegValue = 0x5a;
constexpr unsigned int RegSkip = 0x55;
MdParserSmia::MdParserSmia(std::initializer_list<uint32_t> registerList)
{
for (auto r : registerList)
offsets_[r] = {};
}
MdParser::Status MdParserSmia::parse(libcamera::Span<const uint8_t> buffer,
RegisterMap ®isters)
{
if (reset_) {
/*
* Search again through the metadata for all the registers
* requested.
*/
ASSERT(bitsPerPixel_);
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 != ParseOk)
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] != LineStart)
return NoLineStart;
unsigned int currentOffset = 1; /* after the LineStart */
unsigned int currentLineStart = 0, currentLine = 0;
unsigned int regNum = 0, regsDone = 0;
while (1) {
int tag = buffer[currentOffset++];
/* Non-dummy bytes come in even-sized blocks: skip can only ever follow tag */
while ((bitsPerPixel_ == 10 &&
(currentOffset + 1 - currentLineStart) % 5 == 0) ||
(bitsPerPixel_ == 12 &&
(currentOffset + 1 - currentLineStart) % 3 == 0) ||
(bitsPerPixel_ == 14 &&
(currentOffset - currentLineStart) % 7 >= 4)) {
if (buffer[currentOffset++] != RegSkip)
return BadDummy;
}
int dataByte = buffer[currentOffset++];
if (tag == LineEndTag) {
if (dataByte != LineEndTag)
return BadLineEnd;
if (numLines_ && ++currentLine == numLines_)
return MissingRegs;
if (lineLengthBytes_) {
currentOffset = currentLineStart + lineLengthBytes_;
/* Require whole line to be in the buffer (if buffer size set). */
if (buffer.size() &&
currentOffset + lineLengthBytes_ > buffer.size())
return MissingRegs;
if (buffer[currentOffset] != LineStart)
return NoLineStart;
} else {
/* allow a zero line length to mean "hunt for the next line" */
while (currentOffset < buffer.size() &&
buffer[currentOffset] != LineStart)
currentOffset++;
if (currentOffset == buffer.size())
return NoLineStart;
}
/* inc currentOffset to after LineStart */
currentLineStart = currentOffset++;
} else {
if (tag == RegHiBits)
regNum = (regNum & 0xff) | (dataByte << 8);
else if (tag == RegLowBits)
regNum = (regNum & 0xff00) | dataByte;
else if (tag == RegSkip)
regNum++;
else if (tag == RegValue) {
auto reg = offsets_.find(regNum);
if (reg != offsets_.end()) {
offsets_[regNum] = currentOffset - 1;
if (++regsDone == offsets_.size())
return ParseOk;
}
regNum++;
} else
return IllegalTag;
}
}
}
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