1 files changed, 101 insertions, 0 deletions
diff --git a/src/ipa/raspberrypi/md_parser.cpp b/src/ipa/raspberrypi/md_parser.cpp
new file mode 100644
index 00000000..ca809aa2
--- /dev/null
+++ b/src/ipa/raspberrypi/md_parser.cpp
@@ -0,0 +1,101 @@
+/* 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;
+		}
+	}
+}