summaryrefslogtreecommitdiff
path: root/src/ipa/raspberrypi/md_parser_smia.cpp
blob: 10d677fb5aed62763e5b2dca0c507cb14de075b7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
/* 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 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 &registers)
{
	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++];

		if ((bitsPerPixel_ == 10 &&
		     (currentOffset + 1 - currentLineStart) % 5 == 0) ||
		    (bitsPerPixel_ == 12 &&
		     (currentOffset + 1 - currentLineStart) % 3 == 0)) {
			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;
		}
	}
}