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-rw-r--r--include/media/v4l2-jpeg.h135
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diff --git a/include/media/v4l2-jpeg.h b/include/media/v4l2-jpeg.h
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+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * V4L2 JPEG helpers header
+ *
+ * Copyright (C) 2019 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
+ *
+ * For reference, see JPEG ITU-T.81 (ISO/IEC 10918-1)
+ */
+
+#ifndef _V4L2_JPEG_H
+#define _V4L2_JPEG_H
+
+#include <linux/v4l2-controls.h>
+
+#define V4L2_JPEG_MAX_COMPONENTS 4
+#define V4L2_JPEG_MAX_TABLES 4
+
+/**
+ * struct v4l2_jpeg_reference - reference into the JPEG buffer
+ * @start: pointer to the start of the referenced segment or table
+ * @length: size of the referenced segment or table
+ *
+ * Wnen referencing marker segments, start points right after the marker code,
+ * and length is the size of the segment parameters, excluding the marker code.
+ */
+struct v4l2_jpeg_reference {
+ u8 *start;
+ size_t length;
+};
+
+/* B.2.2 Frame header syntax */
+
+/**
+ * struct v4l2_jpeg_frame_component_spec - frame component-specification
+ * @component_identifier: C[i]
+ * @horizontal_sampling_factor: H[i]
+ * @vertical_sampling_factor: V[i]
+ * @quantization_table_selector: quantization table destination selector Tq[i]
+ */
+struct v4l2_jpeg_frame_component_spec {
+ u8 component_identifier;
+ u8 horizontal_sampling_factor;
+ u8 vertical_sampling_factor;
+ u8 quantization_table_selector;
+};
+
+/**
+ * struct v4l2_jpeg_frame_header - JPEG frame header
+ * @height: Y
+ * @width: X
+ * @precision: P
+ * @num_components: Nf
+ * @component: component-specification, see v4l2_jpeg_frame_component_spec
+ * @subsampling: decoded subsampling from component-specification
+ */
+struct v4l2_jpeg_frame_header {
+ u16 height;
+ u16 width;
+ u8 precision;
+ u8 num_components;
+ struct v4l2_jpeg_frame_component_spec component[V4L2_JPEG_MAX_COMPONENTS];
+ enum v4l2_jpeg_chroma_subsampling subsampling;
+};
+
+/* B.2.3 Scan header syntax */
+
+/**
+ * struct v4l2_jpeg_scan_component_spec - scan component-specification
+ * @component_selector: Cs[j]
+ * @dc_entropy_coding_table_selector: Td[j]
+ * @ac_entropy_coding_table_selector: Ta[j]
+ */
+struct v4l2_jpeg_scan_component_spec {
+ u8 component_selector;
+ u8 dc_entropy_coding_table_selector;
+ u8 ac_entropy_coding_table_selector;
+};
+
+/**
+ * struct v4l2_jpeg_scan_header - JPEG scan header
+ * @num_components: Ns
+ * @component: component-specification, see v4l2_jpeg_scan_component_spec
+ */
+struct v4l2_jpeg_scan_header {
+ u8 num_components; /* Ns */
+ struct v4l2_jpeg_scan_component_spec component[V4L2_JPEG_MAX_COMPONENTS];
+ /* Ss, Se, Ah, and Al are not used by any driver */
+};
+
+/**
+ * struct v4l2_jpeg_header - parsed JPEG header
+ * @sof: pointer to frame header and size
+ * @sos: pointer to scan header and size
+ * @dht: pointers to huffman tables and sizes
+ * @dqt: pointers to quantization tables and sizes
+ * @frame: parsed frame header
+ * @scan: pointer to parsed scan header, optional
+ * @quantization_tables: references to four quantization tables, optional
+ * @huffman_tables: references to four Huffman tables in DC0, DC1, AC0, AC1
+ * order, optional
+ * @restart_interval: number of MCU per restart interval, Ri
+ * @ecs_offset: buffer offset in bytes to the entropy coded segment
+ *
+ * When this structure is passed to v4l2_jpeg_parse_header, the optional scan,
+ * quantization_tables, and huffman_tables pointers must be initialized to NULL
+ * or point at valid memory.
+ */
+struct v4l2_jpeg_header {
+ struct v4l2_jpeg_reference sof;
+ struct v4l2_jpeg_reference sos;
+ unsigned int num_dht;
+ struct v4l2_jpeg_reference dht[V4L2_JPEG_MAX_TABLES];
+ unsigned int num_dqt;
+ struct v4l2_jpeg_reference dqt[V4L2_JPEG_MAX_TABLES];
+
+ struct v4l2_jpeg_frame_header frame;
+ struct v4l2_jpeg_scan_header *scan;
+ struct v4l2_jpeg_reference *quantization_tables;
+ struct v4l2_jpeg_reference *huffman_tables;
+ u16 restart_interval;
+ size_t ecs_offset;
+};
+
+int v4l2_jpeg_parse_header(void *buf, size_t len, struct v4l2_jpeg_header *out);
+
+int v4l2_jpeg_parse_frame_header(void *buf, size_t len,
+ struct v4l2_jpeg_frame_header *frame_header);
+int v4l2_jpeg_parse_scan_header(void *buf, size_t len,
+ struct v4l2_jpeg_scan_header *scan_header);
+int v4l2_jpeg_parse_quantization_tables(void *buf, size_t len, u8 precision,
+ struct v4l2_jpeg_reference *q_tables);
+int v4l2_jpeg_parse_huffman_tables(void *buf, size_t len,
+ struct v4l2_jpeg_reference *huffman_tables);
+
+#endif