media: vicodec: add the FWHT software codec

Add a software codec based on the Fast Walsh Hadamard Transform.

The original FWHT codec was developed by Tom aan de Wiel, and it was
turned into 'proper' kernel code by Hans Verkuil, with a lot of
performance and memory improvements.
Signed-off-by: Tom aan de Wiel <tom.aandewiel@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/vicodec/vicodec-codec.h

+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2016 Tom aan de Wiel
+ * Copyright 2018 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ */
+
+#ifndef VICODEC_RLC_H
+#define VICODEC_RLC_H
+
+#include <linux/types.h>
+#include <linux/bitops.h>
+#include <asm/byteorder.h>
+
+/*
+ * The compressed format consists of a cframe_hdr struct followed by the
+ * compressed frame data. The header contains the size of that data.
+ * Each Y, Cb and Cr plane is compressed separately. If the compressed
+ * size of each plane becomes larger than the uncompressed size, then
+ * that plane is stored uncompressed and the corresponding bit is set
+ * in the flags field of the header.
+ *
+ * Each compressed plane consists of macroblocks and each macroblock
+ * is run-length-encoded. Each macroblock starts with a 16 bit value.
+ * Bit 15 indicates if this is a P-coded macroblock (1) or not (0).
+ * P-coded macroblocks contain a delta against the previous frame.
+ *
+ * Bits 1-12 contain a number. If non-zero, then this same macroblock
+ * repeats that number of times. This results in a high degree of
+ * compression for generated images like colorbars.
+ *
+ * Following this macroblock header the MB coefficients are run-length
+ * encoded: the top 12 bits contain the coefficient, the bottom 4 bits
+ * tell how many times this coefficient occurs. The value 0xf indicates
+ * that the remainder of the macroblock should be filled with zeroes.
+ *
+ * All 16 and 32 bit values are stored in big-endian (network) order.
+ *
+ * Each cframe_hdr starts with an 8 byte magic header that is
+ * guaranteed not to occur in the compressed frame data. This header
+ * can be used to sync to the next frame.
+ *
+ * This codec uses the Fast Walsh Hadamard Transform. Tom aan de Wiel
+ * developed this as part of a university project, specifically for use
+ * with this driver. His project report can be found here:
+ *
+ * https://hverkuil.home.xs4all.nl/fwht.pdf
+ */
+
+/*
+ * Note: bit 0 of the header must always be 0. Otherwise it cannot
+ * be guaranteed that the magic 8 byte sequence (see below) can
+ * never occur in the rlc output.
+ */
+#define PFRAME_BIT (1 << 15)
+#define DUPS_MASK 0x1ffe
+
+/*
+ * This is a sequence of 8 bytes with the low 4 bits set to 0xf.
+ *
+ * This sequence cannot occur in the encoded data
+ */
+#define VICODEC_MAGIC1 0x4f4f4f4f
+#define VICODEC_MAGIC2 0xffffffff
+
+#define VICODEC_VERSION 1
+
+#define VICODEC_MAX_WIDTH 3840
+#define VICODEC_MAX_HEIGHT 2160
+#define VICODEC_MIN_WIDTH 640
+#define VICODEC_MIN_HEIGHT 480
+
+#define PBLOCK 0
+#define IBLOCK 1
+
+/* Set if this is an interlaced format */
+#define VICODEC_FL_IS_INTERLACED	BIT(0)
+/* Set if this is a bottom-first (NTSC) interlaced format */
+#define VICODEC_FL_IS_BOTTOM_FIRST	BIT(1)
+/* Set if each 'frame' contains just one field */
+#define VICODEC_FL_IS_ALTERNATE		BIT(2)
+/*
+ * If VICODEC_FL_IS_ALTERNATE was set, then this is set if this
+ * 'frame' is the bottom field, else it is the top field.
+ */
+#define VICODEC_FL_IS_BOTTOM_FIELD	BIT(3)
+/* Set if this frame is uncompressed */
+#define VICODEC_FL_LUMA_IS_UNCOMPRESSED	BIT(4)
+#define VICODEC_FL_CB_IS_UNCOMPRESSED	BIT(5)
+#define VICODEC_FL_CR_IS_UNCOMPRESSED	BIT(6)
+
+struct cframe_hdr {
+	u32 magic1;
+	u32 magic2;
+	__be32 version;
+	__be32 width, height;
+	__be32 flags;
+	__be32 colorspace;
+	__be32 xfer_func;
+	__be32 ycbcr_enc;
+	__be32 quantization;
+	__be32 size;
+};
+
+struct cframe {
+	unsigned int width, height;
+	__be16 *rlc_data;
+	s16 coeffs[8 * 8];
+	s16 de_coeffs[8 * 8];
+	s16 de_fwht[8 * 8];
+	u32 size;
+};
+
+struct raw_frame {
+	unsigned int width, height;
+	unsigned int chroma_step;
+	u8 *luma, *cb, *cr;
+};
+
+#define FRAME_PCODED	BIT(0)
+#define FRAME_UNENCODED	BIT(1)
+#define LUMA_UNENCODED	BIT(2)
+#define CB_UNENCODED	BIT(3)
+#define CR_UNENCODED	BIT(4)
+
+u32 encode_frame(struct raw_frame *frm, struct raw_frame *ref_frm,
+		 struct cframe *cf, bool is_intra, bool next_is_intra);
+void decode_frame(struct cframe *cf, struct raw_frame *ref, u32 hdr_flags);
+
+#endif