/* SPDX-License-Identifier: BSD-2-Clause */ /* * Copyright (C) 2019, Raspberry Pi (Trading) Limited * * md_parser.cpp - image sensor metadata parsers */ #include <assert.h> #include <map> #include <string.h> #include "md_parser.hpp" using namespace RPi; // 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. #define LINE_START 0x0a #define LINE_END_TAG 0x07 #define REG_HI_BITS 0xaa #define REG_LOW_BITS 0xa5 #define REG_VALUE 0x5a #define REG_SKIP 0x55 MdParserSmia::ParseStatus MdParserSmia::findRegs(unsigned char *data, uint32_t regs[], int offsets[], unsigned int num_regs) { assert(num_regs > 0); if (data[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; ParseStatus retcode = PARSE_OK; while (1) { int tag = data[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 (data[current_offset++] != REG_SKIP) return BAD_DUMMY; } int data_byte = data[current_offset++]; //printf("Offset %u, tag 0x%02x data_byte 0x%02x\n", current_offset-1, tag, data_byte); 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_bytes_ && current_offset + line_length_bytes_ > buffer_size_bytes_) return MISSING_REGS; if (data[current_offset] != LINE_START) return NO_LINE_START; } else { // allow a zero line length to mean "hunt for the next line" while (data[current_offset] != LINE_START && current_offset < buffer_size_bytes_) current_offset++; if (current_offset == buffer_size_bytes_) 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 retcode; } reg_num++; } else return ILLEGAL_TAG; } } }