media: vicodec: rename and use proper fwht prefix for codec

The codec source is generic and not vicodec specific. It can be used
by other drivers or userspace as well. So rename the source and header
to something more generic (codec-fwht.c/h) and prefix the defines, types
and functions with fwht_.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

1 files changed, 849 insertions, 0 deletions

diff --git a/drivers/media/platform/vicodec/codec-fwht.c b/drivers/media/platform/vicodec/codec-fwht.c
new file mode 100644
index 000000000000..f91f90f7e5fc
--- /dev/null
+++ b/drivers/media/platform/vicodec/codec-fwht.c
@@ -0,0 +1,849 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2016 Tom aan de Wiel
+ * Copyright 2018 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * 8x8 Fast Walsh Hadamard Transform in sequency order based on the paper:
+ *
+ * A Recursive Algorithm for Sequency-Ordered Fast Walsh Transforms,
+ * R.D. Brown, 1977
+ */
+
+#include <linux/string.h>
+#include "codec-fwht.h"
+
+/*
+ * 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 BIT(15)
+#define DUPS_MASK 0x1ffe
+
+#define PBLOCK 0
+#define IBLOCK 1
+
+#define ALL_ZEROS 15
+
+static const uint8_t zigzag[64] = {
+	0,
+	1,  8,
+	2,  9, 16,
+	3, 10, 17, 24,
+	4, 11, 18, 25, 32,
+	5, 12, 19, 26, 33, 40,
+	6, 13, 20, 27, 34, 41, 48,
+	7, 14, 21, 28, 35, 42, 49, 56,
+	15, 22, 29, 36, 43, 50, 57,
+	23, 30, 37, 44, 51, 58,
+	31, 38, 45, 52, 59,
+	39, 46, 53, 60,
+	47, 54, 61,
+	55, 62,
+	63,
+};
+
+
+static int rlc(const s16 *in, __be16 *output, int blocktype)
+{
+	s16 block[8 * 8];
+	s16 *wp = block;
+	int i = 0;
+	int x, y;
+	int ret = 0;
+
+	/* read in block from framebuffer */
+	int lastzero_run = 0;
+	int to_encode;
+
+	for (y = 0; y < 8; y++) {
+		for (x = 0; x < 8; x++) {
+			*wp = in[x + y * 8];
+			wp++;
+		}
+	}
+
+	/* keep track of amount of trailing zeros */
+	for (i = 63; i >= 0 && !block[zigzag[i]]; i--)
+		lastzero_run++;
+
+	*output++ = (blocktype == PBLOCK ? htons(PFRAME_BIT) : 0);
+	ret++;
+
+	to_encode = 8 * 8 - (lastzero_run > 14 ? lastzero_run : 0);
+
+	i = 0;
+	while (i < to_encode) {
+		int cnt = 0;
+		int tmp;
+
+		/* count leading zeros */
+		while ((tmp = block[zigzag[i]]) == 0 && cnt < 14) {
+			cnt++;
+			i++;
+			if (i == to_encode) {
+				cnt--;
+				break;
+			}
+		}
+		/* 4 bits for run, 12 for coefficient (quantization by 4) */
+		*output++ = htons((cnt | tmp << 4));
+		i++;
+		ret++;
+	}
+	if (lastzero_run > 14) {
+		*output = htons(ALL_ZEROS | 0);
+		ret++;
+	}
+
+	return ret;
+}
+
+/*
+ * This function will worst-case increase rlc_in by 65*2 bytes:
+ * one s16 value for the header and 8 * 8 coefficients of type s16.
+ */
+static s16 derlc(const __be16 **rlc_in, s16 *dwht_out)
+{
+	/* header */
+	const __be16 *input = *rlc_in;
+	s16 ret = ntohs(*input++);
+	int dec_count = 0;
+	s16 block[8 * 8 + 16];
+	s16 *wp = block;
+	int i;
+
+	/*
+	 * Now de-compress, it expands one byte to up to 15 bytes
+	 * (or fills the remainder of the 64 bytes with zeroes if it
+	 * is the last byte to expand).
+	 *
+	 * So block has to be 8 * 8 + 16 bytes, the '+ 16' is to
+	 * allow for overflow if the incoming data was malformed.
+	 */
+	while (dec_count < 8 * 8) {
+		s16 in = ntohs(*input++);
+		int length = in & 0xf;
+		int coeff = in >> 4;
+
+		/* fill remainder with zeros */
+		if (length == 15) {
+			for (i = 0; i < 64 - dec_count; i++)
+				*wp++ = 0;
+			break;
+		}
+
+		for (i = 0; i < length; i++)
+			*wp++ = 0;
+		*wp++ = coeff;
+		dec_count += length + 1;
+	}
+
+	wp = block;
+
+	for (i = 0; i < 64; i++) {
+		int pos = zigzag[i];
+		int y = pos / 8;
+		int x = pos % 8;
+
+		dwht_out[x + y * 8] = *wp++;
+	}
+	*rlc_in = input;
+	return ret;
+}
+
+static const int quant_table[] = {
+	2, 2, 2, 2, 2, 2,  2,  2,
+	2, 2, 2, 2, 2, 2,  2,  2,
+	2, 2, 2, 2, 2, 2,  2,  3,
+	2, 2, 2, 2, 2, 2,  3,  6,
+	2, 2, 2, 2, 2, 3,  6,  6,
+	2, 2, 2, 2, 3, 6,  6,  6,
+	2, 2, 2, 3, 6, 6,  6,  6,
+	2, 2, 3, 6, 6, 6,  6,  8,
+};
+
+static const int quant_table_p[] = {
+	3, 3, 3, 3, 3, 3,  3,  3,
+	3, 3, 3, 3, 3, 3,  3,  3,
+	3, 3, 3, 3, 3, 3,  3,  3,
+	3, 3, 3, 3, 3, 3,  3,  6,
+	3, 3, 3, 3, 3, 3,  6,  6,
+	3, 3, 3, 3, 3, 6,  6,  9,
+	3, 3, 3, 3, 6, 6,  9,  9,
+	3, 3, 3, 6, 6, 9,  9,  10,
+};
+
+static void quantize_intra(s16 *coeff, s16 *de_coeff, u16 qp)
+{
+	const int *quant = quant_table;
+	int i, j;
+
+	for (j = 0; j < 8; j++) {
+		for (i = 0; i < 8; i++, quant++, coeff++, de_coeff++) {
+			*coeff >>= *quant;
+			if (*coeff >= -qp && *coeff <= qp)
+				*coeff = *de_coeff = 0;
+			else
+				*de_coeff = *coeff << *quant;
+		}
+	}
+}
+
+static void dequantize_intra(s16 *coeff)
+{
+	const int *quant = quant_table;
+	int i, j;
+
+	for (j = 0; j < 8; j++)
+		for (i = 0; i < 8; i++, quant++, coeff++)
+			*coeff <<= *quant;
+}
+
+static void quantize_inter(s16 *coeff, s16 *de_coeff, u16 qp)
+{
+	const int *quant = quant_table_p;
+	int i, j;
+
+	for (j = 0; j < 8; j++) {
+		for (i = 0; i < 8; i++, quant++, coeff++, de_coeff++) {
+			*coeff >>= *quant;
+			if (*coeff >= -qp && *coeff <= qp)
+				*coeff = *de_coeff = 0;
+			else
+				*de_coeff = *coeff << *quant;
+		}
+	}
+}
+
+static void dequantize_inter(s16 *coeff)
+{
+	const int *quant = quant_table_p;
+	int i, j;
+
+	for (j = 0; j < 8; j++)
+		for (i = 0; i < 8; i++, quant++, coeff++)
+			*coeff <<= *quant;
+}
+
+static void fwht(const u8 *block, s16 *output_block, unsigned int stride,
+		 unsigned int input_step, bool intra)
+{
+	/* we'll need more than 8 bits for the transformed coefficients */
+	s32 workspace1[8], workspace2[8];
+	const u8 *tmp = block;
+	s16 *out = output_block;
+	int add = intra ? 256 : 0;
+	unsigned int i;
+
+	/* stage 1 */
+	stride *= input_step;
+
+	for (i = 0; i < 8; i++, tmp += stride, out += 8) {
+		switch (input_step) {
+		case 1:
+			workspace1[0]  = tmp[0] + tmp[1] - add;
+			workspace1[1]  = tmp[0] - tmp[1];
+
+			workspace1[2]  = tmp[2] + tmp[3] - add;
+			workspace1[3]  = tmp[2] - tmp[3];
+
+			workspace1[4]  = tmp[4] + tmp[5] - add;
+			workspace1[5]  = tmp[4] - tmp[5];
+
+			workspace1[6]  = tmp[6] + tmp[7] - add;
+			workspace1[7]  = tmp[6] - tmp[7];
+			break;
+		case 2:
+			workspace1[0]  = tmp[0] + tmp[2] - add;
+			workspace1[1]  = tmp[0] - tmp[2];
+
+			workspace1[2]  = tmp[4] + tmp[6] - add;
+			workspace1[3]  = tmp[4] - tmp[6];
+
+			workspace1[4]  = tmp[8] + tmp[10] - add;
+			workspace1[5]  = tmp[8] - tmp[10];
+
+			workspace1[6]  = tmp[12] + tmp[14] - add;
+			workspace1[7]  = tmp[12] - tmp[14];
+			break;
+		case 3:
+			workspace1[0]  = tmp[0] + tmp[3] - add;
+			workspace1[1]  = tmp[0] - tmp[3];
+
+			workspace1[2]  = tmp[6] + tmp[9] - add;
+			workspace1[3]  = tmp[6] - tmp[9];
+
+			workspace1[4]  = tmp[12] + tmp[15] - add;
+			workspace1[5]  = tmp[12] - tmp[15];
+
+			workspace1[6]  = tmp[18] + tmp[21] - add;
+			workspace1[7]  = tmp[18] - tmp[21];
+			break;
+		default:
+			workspace1[0]  = tmp[0] + tmp[4] - add;
+			workspace1[1]  = tmp[0] - tmp[4];
+
+			workspace1[2]  = tmp[8] + tmp[12] - add;
+			workspace1[3]  = tmp[8] - tmp[12];
+
+			workspace1[4]  = tmp[16] + tmp[20] - add;
+			workspace1[5]  = tmp[16] - tmp[20];
+
+			workspace1[6]  = tmp[24] + tmp[28] - add;
+			workspace1[7]  = tmp[24] - tmp[28];
+			break;
+		}
+
+		/* stage 2 */
+		workspace2[0] = workspace1[0] + workspace1[2];
+		workspace2[1] = workspace1[0] - workspace1[2];
+		workspace2[2] = workspace1[1] - workspace1[3];
+		workspace2[3] = workspace1[1] + workspace1[3];
+
+		workspace2[4] = workspace1[4] + workspace1[6];
+		workspace2[5] = workspace1[4] - workspace1[6];
+		workspace2[6] = workspace1[5] - workspace1[7];
+		workspace2[7] = workspace1[5] + workspace1[7];
+
+		/* stage 3 */
+		out[0] = workspace2[0] + workspace2[4];
+		out[1] = workspace2[0] - workspace2[4];
+		out[2] = workspace2[1] - workspace2[5];
+		out[3] = workspace2[1] + workspace2[5];
+		out[4] = workspace2[2] + workspace2[6];
+		out[5] = workspace2[2] - workspace2[6];
+		out[6] = workspace2[3] - workspace2[7];
+		out[7] = workspace2[3] + workspace2[7];
+	}
+
+	out = output_block;
+
+	for (i = 0; i < 8; i++, out++) {
+		/* stage 1 */
+		workspace1[0]  = out[0] + out[1 * 8];
+		workspace1[1]  = out[0] - out[1 * 8];
+
+		workspace1[2]  = out[2 * 8] + out[3 * 8];
+		workspace1[3]  = out[2 * 8] - out[3 * 8];
+
+		workspace1[4]  = out[4 * 8] + out[5 * 8];
+		workspace1[5]  = out[4 * 8] - out[5 * 8];
+
+		workspace1[6]  = out[6 * 8] + out[7 * 8];
+		workspace1[7]  = out[6 * 8] - out[7 * 8];
+
+		/* stage 2 */
+		workspace2[0] = workspace1[0] + workspace1[2];
+		workspace2[1] = workspace1[0] - workspace1[2];
+		workspace2[2] = workspace1[1] - workspace1[3];
+		workspace2[3] = workspace1[1] + workspace1[3];
+
+		workspace2[4] = workspace1[4] + workspace1[6];
+		workspace2[5] = workspace1[4] - workspace1[6];
+		workspace2[6] = workspace1[5] - workspace1[7];
+		workspace2[7] = workspace1[5] + workspace1[7];
+		/* stage 3 */
+		out[0 * 8] = workspace2[0] + workspace2[4];
+		out[1 * 8] = workspace2[0] - workspace2[4];
+		out[2 * 8] = workspace2[1] - workspace2[5];
+		out[3 * 8] = workspace2[1] + workspace2[5];
+		out[4 * 8] = workspace2[2] + workspace2[6];
+		out[5 * 8] = workspace2[2] - workspace2[6];
+		out[6 * 8] = workspace2[3] - workspace2[7];
+		out[7 * 8] = workspace2[3] + workspace2[7];
+	}
+}
+
+/*
+ * Not the nicest way of doing it, but P-blocks get twice the range of
+ * that of the I-blocks. Therefore we need a type bigger than 8 bits.
+ * Furthermore values can be negative... This is just a version that
+ * works with 16 signed data
+ */
+static void fwht16(const s16 *block, s16 *output_block, int stride, int intra)
+{
+	/* we'll need more than 8 bits for the transformed coefficients */
+	s32 workspace1[8], workspace2[8];
+	const s16 *tmp = block;
+	s16 *out = output_block;
+	int i;
+
+	for (i = 0; i < 8; i++, tmp += stride, out += 8) {
+		/* stage 1 */
+		workspace1[0]  = tmp[0] + tmp[1];
+		workspace1[1]  = tmp[0] - tmp[1];
+
+		workspace1[2]  = tmp[2] + tmp[3];
+		workspace1[3]  = tmp[2] - tmp[3];
+
+		workspace1[4]  = tmp[4] + tmp[5];
+		workspace1[5]  = tmp[4] - tmp[5];
+
+		workspace1[6]  = tmp[6] + tmp[7];
+		workspace1[7]  = tmp[6] - tmp[7];
+
+		/* stage 2 */
+		workspace2[0] = workspace1[0] + workspace1[2];
+		workspace2[1] = workspace1[0] - workspace1[2];
+		workspace2[2] = workspace1[1] - workspace1[3];
+		workspace2[3] = workspace1[1] + workspace1[3];
+
+		workspace2[4] = workspace1[4] + workspace1[6];
+		workspace2[5] = workspace1[4] - workspace1[6];
+		workspace2[6] = workspace1[5] - workspace1[7];
+		workspace2[7] = workspace1[5] + workspace1[7];
+
+		/* stage 3 */
+		out[0] = workspace2[0] + workspace2[4];
+		out[1] = workspace2[0] - workspace2[4];
+		out[2] = workspace2[1] - workspace2[5];
+		out[3] = workspace2[1] + workspace2[5];
+		out[4] = workspace2[2] + workspace2[6];
+		out[5] = workspace2[2] - workspace2[6];
+		out[6] = workspace2[3] - workspace2[7];
+		out[7] = workspace2[3] + workspace2[7];
+	}
+
+	out = output_block;
+
+	for (i = 0; i < 8; i++, out++) {
+		/* stage 1 */
+		workspace1[0]  = out[0] + out[1*8];
+		workspace1[1]  = out[0] - out[1*8];
+
+		workspace1[2]  = out[2*8] + out[3*8];
+		workspace1[3]  = out[2*8] - out[3*8];
+
+		workspace1[4]  = out[4*8] + out[5*8];
+		workspace1[5]  = out[4*8] - out[5*8];
+
+		workspace1[6]  = out[6*8] + out[7*8];
+		workspace1[7]  = out[6*8] - out[7*8];
+
+		/* stage 2 */
+		workspace2[0] = workspace1[0] + workspace1[2];
+		workspace2[1] = workspace1[0] - workspace1[2];
+		workspace2[2] = workspace1[1] - workspace1[3];
+		workspace2[3] = workspace1[1] + workspace1[3];
+
+		workspace2[4] = workspace1[4] + workspace1[6];
+		workspace2[5] = workspace1[4] - workspace1[6];
+		workspace2[6] = workspace1[5] - workspace1[7];
+		workspace2[7] = workspace1[5] + workspace1[7];
+
+		/* stage 3 */
+		out[0*8] = workspace2[0] + workspace2[4];
+		out[1*8] = workspace2[0] - workspace2[4];
+		out[2*8] = workspace2[1] - workspace2[5];
+		out[3*8] = workspace2[1] + workspace2[5];
+		out[4*8] = workspace2[2] + workspace2[6];
+		out[5*8] = workspace2[2] - workspace2[6];
+		out[6*8] = workspace2[3] - workspace2[7];
+		out[7*8] = workspace2[3] + workspace2[7];
+	}
+}
+
+static void ifwht(const s16 *block, s16 *output_block, int intra)
+{
+	/*
+	 * we'll need more than 8 bits for the transformed coefficients
+	 * use native unit of cpu
+	 */
+	int workspace1[8], workspace2[8];
+	int inter = intra ? 0 : 1;
+	const s16 *tmp = block;
+	s16 *out = output_block;
+	int i;
+
+	for (i = 0; i < 8; i++, tmp += 8, out += 8) {
+		/* stage 1 */
+		workspace1[0]  = tmp[0] + tmp[1];
+		workspace1[1]  = tmp[0] - tmp[1];
+
+		workspace1[2]  = tmp[2] + tmp[3];
+		workspace1[3]  = tmp[2] - tmp[3];
+
+		workspace1[4]  = tmp[4] + tmp[5];
+		workspace1[5]  = tmp[4] - tmp[5];
+
+		workspace1[6]  = tmp[6] + tmp[7];
+		workspace1[7]  = tmp[6] - tmp[7];
+
+		/* stage 2 */
+		workspace2[0] = workspace1[0] + workspace1[2];
+		workspace2[1] = workspace1[0] - workspace1[2];
+		workspace2[2] = workspace1[1] - workspace1[3];
+		workspace2[3] = workspace1[1] + workspace1[3];
+
+		workspace2[4] = workspace1[4] + workspace1[6];
+		workspace2[5] = workspace1[4] - workspace1[6];
+		workspace2[6] = workspace1[5] - workspace1[7];
+		workspace2[7] = workspace1[5] + workspace1[7];
+
+		/* stage 3 */
+		out[0] = workspace2[0] + workspace2[4];
+		out[1] = workspace2[0] - workspace2[4];
+		out[2] = workspace2[1] - workspace2[5];
+		out[3] = workspace2[1] + workspace2[5];
+		out[4] = workspace2[2] + workspace2[6];
+		out[5] = workspace2[2] - workspace2[6];
+		out[6] = workspace2[3] - workspace2[7];
+		out[7] = workspace2[3] + workspace2[7];
+	}
+
+	out = output_block;
+
+	for (i = 0; i < 8; i++, out++) {
+		/* stage 1 */
+		workspace1[0]  = out[0] + out[1 * 8];
+		workspace1[1]  = out[0] - out[1 * 8];
+
+		workspace1[2]  = out[2 * 8] + out[3 * 8];
+		workspace1[3]  = out[2 * 8] - out[3 * 8];
+
+		workspace1[4]  = out[4 * 8] + out[5 * 8];
+		workspace1[5]  = out[4 * 8] - out[5 * 8];
+
+		workspace1[6]  = out[6 * 8] + out[7 * 8];
+		workspace1[7]  = out[6 * 8] - out[7 * 8];
+
+		/* stage 2 */
+		workspace2[0] = workspace1[0] + workspace1[2];
+		workspace2[1] = workspace1[0] - workspace1[2];
+		workspace2[2] = workspace1[1] - workspace1[3];
+		workspace2[3] = workspace1[1] + workspace1[3];
+
+		workspace2[4] = workspace1[4] + workspace1[6];
+		workspace2[5] = workspace1[4] - workspace1[6];
+		workspace2[6] = workspace1[5] - workspace1[7];
+		workspace2[7] = workspace1[5] + workspace1[7];
+
+		/* stage 3 */
+		if (inter) {
+			int d;
+
+			out[0 * 8] = workspace2[0] + workspace2[4];
+			out[1 * 8] = workspace2[0] - workspace2[4];
+			out[2 * 8] = workspace2[1] - workspace2[5];
+			out[3 * 8] = workspace2[1] + workspace2[5];
+			out[4 * 8] = workspace2[2] + workspace2[6];
+			out[5 * 8] = workspace2[2] - workspace2[6];
+			out[6 * 8] = workspace2[3] - workspace2[7];
+			out[7 * 8] = workspace2[3] + workspace2[7];
+
+			for (d = 0; d < 8; d++)
+				out[8 * d] >>= 6;
+		} else {
+			int d;
+
+			out[0 * 8] = workspace2[0] + workspace2[4];
+			out[1 * 8] = workspace2[0] - workspace2[4];
+			out[2 * 8] = workspace2[1] - workspace2[5];
+			out[3 * 8] = workspace2[1] + workspace2[5];
+			out[4 * 8] = workspace2[2] + workspace2[6];
+			out[5 * 8] = workspace2[2] - workspace2[6];
+			out[6 * 8] = workspace2[3] - workspace2[7];
+			out[7 * 8] = workspace2[3] + workspace2[7];
+
+			for (d = 0; d < 8; d++) {
+				out[8 * d] >>= 6;
+				out[8 * d] += 128;
+			}
+		}
+	}
+}
+
+static void fill_encoder_block(const u8 *input, s16 *dst,
+			       unsigned int stride, unsigned int input_step)
+{
+	int i, j;
+
+	for (i = 0; i < 8; i++) {
+		for (j = 0; j < 8; j++, input += input_step)
+			*dst++ = *input;
+		input += (stride - 8) * input_step;
+	}
+}
+
+static int var_intra(const s16 *input)
+{
+	int32_t mean = 0;
+	int32_t ret = 0;
+	const s16 *tmp = input;
+	int i;
+
+	for (i = 0; i < 8 * 8; i++, tmp++)
+		mean += *tmp;
+	mean /= 64;
+	tmp = input;
+	for (i = 0; i < 8 * 8; i++, tmp++)
+		ret += (*tmp - mean) < 0 ? -(*tmp - mean) : (*tmp - mean);
+	return ret;
+}
+
+static int var_inter(const s16 *old, const s16 *new)
+{
+	int32_t ret = 0;
+	int i;
+
+	for (i = 0; i < 8 * 8; i++, old++, new++)
+		ret += (*old - *new) < 0 ? -(*old - *new) : (*old - *new);
+	return ret;
+}
+
+static int decide_blocktype(const u8 *cur, const u8 *reference,
+			    s16 *deltablock, unsigned int stride,
+			    unsigned int input_step)
+{
+	s16 tmp[64];
+	s16 old[64];
+	s16 *work = tmp;
+	unsigned int k, l;
+	int vari;
+	int vard;
+
+	fill_encoder_block(cur, tmp, stride, input_step);
+	fill_encoder_block(reference, old, 8, 1);
+	vari = var_intra(tmp);
+
+	for (k = 0; k < 8; k++) {
+		for (l = 0; l < 8; l++) {
+			*deltablock = *work - *reference;
+			deltablock++;
+			work++;
+			reference++;
+		}
+	}
+	deltablock -= 64;
+	vard = var_inter(old, tmp);
+	return vari <= vard ? IBLOCK : PBLOCK;
+}
+
+static void fill_decoder_block(u8 *dst, const s16 *input, int stride)
+{
+	int i, j;
+
+	for (i = 0; i < 8; i++) {
+		for (j = 0; j < 8; j++)
+			*dst++ = *input++;
+		dst += stride - 8;
+	}
+}
+
+static void add_deltas(s16 *deltas, const u8 *ref, int stride)
+{
+	int k, l;
+
+	for (k = 0; k < 8; k++) {
+		for (l = 0; l < 8; l++) {
+			*deltas += *ref++;
+			/*
+			 * Due to quantizing, it might possible that the
+			 * decoded coefficients are slightly out of range
+			 */
+			if (*deltas < 0)
+				*deltas = 0;
+			else if (*deltas > 255)
+				*deltas = 255;
+			deltas++;
+		}
+		ref += stride - 8;
+	}
+}
+
+static u32 encode_plane(u8 *input, u8 *refp, __be16 **rlco, __be16 *rlco_max,
+			struct fwht_cframe *cf, u32 height, u32 width,
+			unsigned int input_step,
+			bool is_intra, bool next_is_intra)
+{
+	u8 *input_start = input;
+	__be16 *rlco_start = *rlco;
+	s16 deltablock[64];
+	__be16 pframe_bit = htons(PFRAME_BIT);
+	u32 encoding = 0;
+	unsigned int last_size = 0;
+	unsigned int i, j;
+
+	for (j = 0; j < height / 8; j++) {
+		for (i = 0; i < width / 8; i++) {
+			/* intra code, first frame is always intra coded. */
+			int blocktype = IBLOCK;
+			unsigned int size;
+
+			if (!is_intra)
+				blocktype = decide_blocktype(input, refp,
+					deltablock, width, input_step);
+			if (blocktype == IBLOCK) {
+				fwht(input, cf->coeffs, width, input_step, 1);
+				quantize_intra(cf->coeffs, cf->de_coeffs,
+					       cf->i_frame_qp);
+			} else {
+				/* inter code */
+				encoding |= FWHT_FRAME_PCODED;
+				fwht16(deltablock, cf->coeffs, 8, 0);
+				quantize_inter(cf->coeffs, cf->de_coeffs,
+					       cf->p_frame_qp);
+			}
+			if (!next_is_intra) {
+				ifwht(cf->de_coeffs, cf->de_fwht, blocktype);
+
+				if (blocktype == PBLOCK)
+					add_deltas(cf->de_fwht, refp, 8);
+				fill_decoder_block(refp, cf->de_fwht, 8);
+			}
+
+			input += 8 * input_step;
+			refp += 8 * 8;
+
+			size = rlc(cf->coeffs, *rlco, blocktype);
+			if (last_size == size &&
+			    !memcmp(*rlco + 1, *rlco - size + 1, 2 * size - 2)) {
+				__be16 *last_rlco = *rlco - size;
+				s16 hdr = ntohs(*last_rlco);
+
+				if (!((*last_rlco ^ **rlco) & pframe_bit) &&
+				    (hdr & DUPS_MASK) < DUPS_MASK)
+					*last_rlco = htons(hdr + 2);
+				else
+					*rlco += size;
+			} else {
+				*rlco += size;
+			}
+			if (*rlco >= rlco_max) {
+				encoding |= FWHT_FRAME_UNENCODED;
+				goto exit_loop;
+			}
+			last_size = size;
+		}
+		input += width * 7 * input_step;
+	}
+
+exit_loop:
+	if (encoding & FWHT_FRAME_UNENCODED) {
+		u8 *out = (u8 *)rlco_start;
+
+		input = input_start;
+		/*
+		 * The compressed stream should never contain the magic
+		 * header, so when we copy the YUV data we replace 0xff
+		 * by 0xfe. Since YUV is limited range such values
+		 * shouldn't appear anyway.
+		 */
+		for (i = 0; i < height * width; i++, input += input_step)
+			*out++ = (*input == 0xff) ? 0xfe : *input;
+		*rlco = (__be16 *)out;
+		encoding &= ~FWHT_FRAME_PCODED;
+	}
+	return encoding;
+}
+
+u32 fwht_encode_frame(struct fwht_raw_frame *frm,
+		      struct fwht_raw_frame *ref_frm,
+		      struct fwht_cframe *cf,
+		      bool is_intra, bool next_is_intra)
+{
+	unsigned int size = frm->height * frm->width;
+	__be16 *rlco = cf->rlc_data;
+	__be16 *rlco_max;
+	u32 encoding;
+	u32 chroma_h = frm->height / frm->height_div;
+	u32 chroma_w = frm->width / frm->width_div;
+	unsigned int chroma_size = chroma_h * chroma_w;
+
+	rlco_max = rlco + size / 2 - 256;
+	encoding = encode_plane(frm->luma, ref_frm->luma, &rlco, rlco_max, cf,
+				frm->height, frm->width,
+				frm->luma_step, is_intra, next_is_intra);
+	if (encoding & FWHT_FRAME_UNENCODED)
+		encoding |= FWHT_LUMA_UNENCODED;
+	encoding &= ~FWHT_FRAME_UNENCODED;
+	rlco_max = rlco + chroma_size / 2 - 256;
+	encoding |= encode_plane(frm->cb, ref_frm->cb, &rlco, rlco_max, cf,
+				 chroma_h, chroma_w,
+				 frm->chroma_step, is_intra, next_is_intra);
+	if (encoding & FWHT_FRAME_UNENCODED)
+		encoding |= FWHT_CB_UNENCODED;
+	encoding &= ~FWHT_FRAME_UNENCODED;
+	rlco_max = rlco + chroma_size / 2 - 256;
+	encoding |= encode_plane(frm->cr, ref_frm->cr, &rlco, rlco_max, cf,
+				 chroma_h, chroma_w,
+				 frm->chroma_step, is_intra, next_is_intra);
+	if (encoding & FWHT_FRAME_UNENCODED)
+		encoding |= FWHT_CR_UNENCODED;
+	encoding &= ~FWHT_FRAME_UNENCODED;
+	cf->size = (rlco - cf->rlc_data) * sizeof(*rlco);
+	return encoding;
+}
+
+static void decode_plane(struct fwht_cframe *cf, const __be16 **rlco, u8 *ref,
+			 u32 height, u32 width, bool uncompressed)
+{
+	unsigned int copies = 0;
+	s16 copy[8 * 8];
+	s16 stat;
+	unsigned int i, j;
+
+	if (uncompressed) {
+		memcpy(ref, *rlco, width * height);
+		*rlco += width * height / 2;
+		return;
+	}
+
+	/*
+	 * When decoding each macroblock the rlco pointer will be increased
+	 * by 65 * 2 bytes worst-case.
+	 * To avoid overflow the buffer has to be 65/64th of the actual raw
+	 * image size, just in case someone feeds it malicious data.
+	 */
+	for (j = 0; j < height / 8; j++) {
+		for (i = 0; i < width / 8; i++) {
+			u8 *refp = ref + j * 8 * width + i * 8;
+
+			if (copies) {
+				memcpy(cf->de_fwht, copy, sizeof(copy));
+				if (stat & PFRAME_BIT)
+					add_deltas(cf->de_fwht, refp, width);
+				fill_decoder_block(refp, cf->de_fwht, width);
+				copies--;
+				continue;
+			}
+
+			stat = derlc(rlco, cf->coeffs);
+
+			if (stat & PFRAME_BIT)
+				dequantize_inter(cf->coeffs);
+			else
+				dequantize_intra(cf->coeffs);
+
+			ifwht(cf->coeffs, cf->de_fwht,
+			      (stat & PFRAME_BIT) ? 0 : 1);
+
+			copies = (stat & DUPS_MASK) >> 1;
+			if (copies)
+				memcpy(copy, cf->de_fwht, sizeof(copy));
+			if (stat & PFRAME_BIT)
+				add_deltas(cf->de_fwht, refp, width);
+			fill_decoder_block(refp, cf->de_fwht, width);
+		}
+	}
+}
+
+void fwht_decode_frame(struct fwht_cframe *cf, struct fwht_raw_frame *ref,
+		       u32 hdr_flags)
+{
+	const __be16 *rlco = cf->rlc_data;
+	u32 h = cf->height / 2;
+	u32 w = cf->width / 2;
+
+	if (hdr_flags & FWHT_FL_CHROMA_FULL_HEIGHT)
+		h *= 2;
+	if (hdr_flags & FWHT_FL_CHROMA_FULL_WIDTH)
+		w *= 2;
+	decode_plane(cf, &rlco, ref->luma, cf->height, cf->width,
+		     hdr_flags & FWHT_FL_LUMA_IS_UNCOMPRESSED);
+	decode_plane(cf, &rlco, ref->cb, h, w,
+		     hdr_flags & FWHT_FL_CB_IS_UNCOMPRESSED);
+	decode_plane(cf, &rlco, ref->cr, h, w,
+		     hdr_flags & FWHT_FL_CR_IS_UNCOMPRESSED);
+}