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/* SPDX-License-Identifier: BSD-2-Clause */
/*
* Copyright (C) 2019-2021, Raspberry Pi (Trading) Limited
*
* md_parser_smia.cpp - SMIA specification based embedded data parser
*/
#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
* 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 LINE_START = 0x0a;
constexpr unsigned int LINE_END_TAG = 0x07;
constexpr unsigned int REG_HI_BITS = 0xaa;
constexpr unsigned int REG_LOW_BITS = 0xa5;
constexpr unsigned int REG_VALUE = 0x5a;
constexpr unsigned int REG_SKIP = 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(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, regs_done = 0;
while (1) {
int tag = buffer[current_offset++];
if ((bits_per_pixel_ == 10 &&
(current_offset + 1 - current_line_start) % 5 == 0) ||
(bits_per_pixel_ == 12 &&
(current_offset + 1 - current_line_start) % 3 == 0)) {
if (buffer[current_offset++] != REG_SKIP)
return BAD_DUMMY;
}
int data_byte = buffer[current_offset++];
if (tag == LINE_END_TAG) {
if (data_byte != LINE_END_TAG)
return BAD_LINE_END;
if (num_lines_ && ++current_line == num_lines_)
return MISSING_REGS;
if (line_length_bytes_) {
current_offset = current_line_start + line_length_bytes_;
/* Require whole line to be in the buffer (if buffer size set). */
if (buffer.size() &&
current_offset + line_length_bytes_ > buffer.size())
return MISSING_REGS;
if (buffer[current_offset] != LINE_START)
return NO_LINE_START;
} else {
/* allow a zero line length to mean "hunt for the next line" */
while (current_offset < buffer.size() &&
buffer[current_offset] != LINE_START)
current_offset++;
if (current_offset == buffer.size())
return NO_LINE_START;
}
/* inc current_offset to after LINE_START */
current_line_start = current_offset++;
} else {
if (tag == REG_HI_BITS)
reg_num = (reg_num & 0xff) | (data_byte << 8);
else if (tag == REG_LOW_BITS)
reg_num = (reg_num & 0xff00) | data_byte;
else if (tag == REG_SKIP)
reg_num++;
else if (tag == REG_VALUE) {
auto reg = offsets_.find(reg_num);
if (reg != offsets_.end()) {
offsets_[reg_num] = current_offset - 1;
if (++regs_done == offsets_.size())
return PARSE_OK;
}
reg_num++;
} else
return ILLEGAL_TAG;
}
}
}
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