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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 <assert.h>
#include "md_parser.hpp"
using namespace RPiController;
/*
* 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::ParseStatus MdParserSmia::findRegs(libcamera::Span<const uint8_t> buffer,
uint32_t regs[], int offsets[],
unsigned int num_regs)
{
assert(num_regs > 0);
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;
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 (buffer[current_offset] != LINE_START &&
current_offset < buffer.size())
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) {
while (reg_num >=
/* assumes registers are in order... */
regs[first_reg]) {
if (reg_num == regs[first_reg])
offsets[first_reg] = current_offset - 1;
if (++first_reg == num_regs)
return PARSE_OK;
}
reg_num++;
} else
return ILLEGAL_TAG;
}
}
}
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