162306a36Sopenharmony_ci// SPDX-License-Identifier: GPL-2.0-only
262306a36Sopenharmony_ci/*
362306a36Sopenharmony_ci * vivid-vbi-gen.c - vbi generator support functions.
462306a36Sopenharmony_ci *
562306a36Sopenharmony_ci * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
662306a36Sopenharmony_ci */
762306a36Sopenharmony_ci
862306a36Sopenharmony_ci#include <linux/errno.h>
962306a36Sopenharmony_ci#include <linux/kernel.h>
1062306a36Sopenharmony_ci#include <linux/ktime.h>
1162306a36Sopenharmony_ci#include <linux/string.h>
1262306a36Sopenharmony_ci#include <linux/videodev2.h>
1362306a36Sopenharmony_ci
1462306a36Sopenharmony_ci#include "vivid-vbi-gen.h"
1562306a36Sopenharmony_ci
1662306a36Sopenharmony_cistatic void wss_insert(u8 *wss, u32 val, unsigned size)
1762306a36Sopenharmony_ci{
1862306a36Sopenharmony_ci	while (size--)
1962306a36Sopenharmony_ci		*wss++ = (val & (1 << size)) ? 0xc0 : 0x10;
2062306a36Sopenharmony_ci}
2162306a36Sopenharmony_ci
2262306a36Sopenharmony_cistatic void vivid_vbi_gen_wss_raw(const struct v4l2_sliced_vbi_data *data,
2362306a36Sopenharmony_ci		u8 *buf, unsigned sampling_rate)
2462306a36Sopenharmony_ci{
2562306a36Sopenharmony_ci	const unsigned rate = 5000000;	/* WSS has a 5 MHz transmission rate */
2662306a36Sopenharmony_ci	u8 wss[29 + 24 + 24 + 24 + 18 + 18] = { 0 };
2762306a36Sopenharmony_ci	const unsigned zero = 0x07;
2862306a36Sopenharmony_ci	const unsigned one = 0x38;
2962306a36Sopenharmony_ci	unsigned bit = 0;
3062306a36Sopenharmony_ci	u16 wss_data;
3162306a36Sopenharmony_ci	int i;
3262306a36Sopenharmony_ci
3362306a36Sopenharmony_ci	wss_insert(wss + bit, 0x1f1c71c7, 29); bit += 29;
3462306a36Sopenharmony_ci	wss_insert(wss + bit, 0x1e3c1f, 24); bit += 24;
3562306a36Sopenharmony_ci
3662306a36Sopenharmony_ci	wss_data = (data->data[1] << 8) | data->data[0];
3762306a36Sopenharmony_ci	for (i = 0; i <= 13; i++, bit += 6)
3862306a36Sopenharmony_ci		wss_insert(wss + bit, (wss_data & (1 << i)) ? one : zero, 6);
3962306a36Sopenharmony_ci
4062306a36Sopenharmony_ci	for (i = 0, bit = 0; bit < sizeof(wss); bit++) {
4162306a36Sopenharmony_ci		unsigned n = ((bit + 1) * sampling_rate) / rate;
4262306a36Sopenharmony_ci
4362306a36Sopenharmony_ci		while (i < n)
4462306a36Sopenharmony_ci			buf[i++] = wss[bit];
4562306a36Sopenharmony_ci	}
4662306a36Sopenharmony_ci}
4762306a36Sopenharmony_ci
4862306a36Sopenharmony_cistatic void vivid_vbi_gen_teletext_raw(const struct v4l2_sliced_vbi_data *data,
4962306a36Sopenharmony_ci		u8 *buf, unsigned sampling_rate)
5062306a36Sopenharmony_ci{
5162306a36Sopenharmony_ci	const unsigned rate = 6937500 / 10;	/* Teletext has a 6.9375 MHz transmission rate */
5262306a36Sopenharmony_ci	u8 teletext[45] = { 0x55, 0x55, 0x27 };
5362306a36Sopenharmony_ci	unsigned bit = 0;
5462306a36Sopenharmony_ci	int i;
5562306a36Sopenharmony_ci
5662306a36Sopenharmony_ci	memcpy(teletext + 3, data->data, sizeof(teletext) - 3);
5762306a36Sopenharmony_ci	/* prevents 32 bit overflow */
5862306a36Sopenharmony_ci	sampling_rate /= 10;
5962306a36Sopenharmony_ci
6062306a36Sopenharmony_ci	for (i = 0, bit = 0; bit < sizeof(teletext) * 8; bit++) {
6162306a36Sopenharmony_ci		unsigned n = ((bit + 1) * sampling_rate) / rate;
6262306a36Sopenharmony_ci		u8 val = (teletext[bit / 8] & (1 << (bit & 7))) ? 0xc0 : 0x10;
6362306a36Sopenharmony_ci
6462306a36Sopenharmony_ci		while (i < n)
6562306a36Sopenharmony_ci			buf[i++] = val;
6662306a36Sopenharmony_ci	}
6762306a36Sopenharmony_ci}
6862306a36Sopenharmony_ci
6962306a36Sopenharmony_cistatic void cc_insert(u8 *cc, u8 ch)
7062306a36Sopenharmony_ci{
7162306a36Sopenharmony_ci	unsigned tot = 0;
7262306a36Sopenharmony_ci	unsigned i;
7362306a36Sopenharmony_ci
7462306a36Sopenharmony_ci	for (i = 0; i < 7; i++) {
7562306a36Sopenharmony_ci		cc[2 * i] = cc[2 * i + 1] = (ch & (1 << i)) ? 1 : 0;
7662306a36Sopenharmony_ci		tot += cc[2 * i];
7762306a36Sopenharmony_ci	}
7862306a36Sopenharmony_ci	cc[14] = cc[15] = !(tot & 1);
7962306a36Sopenharmony_ci}
8062306a36Sopenharmony_ci
8162306a36Sopenharmony_ci#define CC_PREAMBLE_BITS (14 + 4 + 2)
8262306a36Sopenharmony_ci
8362306a36Sopenharmony_cistatic void vivid_vbi_gen_cc_raw(const struct v4l2_sliced_vbi_data *data,
8462306a36Sopenharmony_ci		u8 *buf, unsigned sampling_rate)
8562306a36Sopenharmony_ci{
8662306a36Sopenharmony_ci	const unsigned rate = 1000000;	/* CC has a 1 MHz transmission rate */
8762306a36Sopenharmony_ci
8862306a36Sopenharmony_ci	u8 cc[CC_PREAMBLE_BITS + 2 * 16] = {
8962306a36Sopenharmony_ci		/* Clock run-in: 7 cycles */
9062306a36Sopenharmony_ci		0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
9162306a36Sopenharmony_ci		/* 2 cycles of 0 */
9262306a36Sopenharmony_ci		0, 0, 0, 0,
9362306a36Sopenharmony_ci		/* Start bit of 1 (each bit is two cycles) */
9462306a36Sopenharmony_ci		1, 1
9562306a36Sopenharmony_ci	};
9662306a36Sopenharmony_ci	unsigned bit, i;
9762306a36Sopenharmony_ci
9862306a36Sopenharmony_ci	cc_insert(cc + CC_PREAMBLE_BITS, data->data[0]);
9962306a36Sopenharmony_ci	cc_insert(cc + CC_PREAMBLE_BITS + 16, data->data[1]);
10062306a36Sopenharmony_ci
10162306a36Sopenharmony_ci	for (i = 0, bit = 0; bit < sizeof(cc); bit++) {
10262306a36Sopenharmony_ci		unsigned n = ((bit + 1) * sampling_rate) / rate;
10362306a36Sopenharmony_ci
10462306a36Sopenharmony_ci		while (i < n)
10562306a36Sopenharmony_ci			buf[i++] = cc[bit] ? 0xc0 : 0x10;
10662306a36Sopenharmony_ci	}
10762306a36Sopenharmony_ci}
10862306a36Sopenharmony_ci
10962306a36Sopenharmony_civoid vivid_vbi_gen_raw(const struct vivid_vbi_gen_data *vbi,
11062306a36Sopenharmony_ci		const struct v4l2_vbi_format *vbi_fmt, u8 *buf)
11162306a36Sopenharmony_ci{
11262306a36Sopenharmony_ci	unsigned idx;
11362306a36Sopenharmony_ci
11462306a36Sopenharmony_ci	for (idx = 0; idx < 25; idx++) {
11562306a36Sopenharmony_ci		const struct v4l2_sliced_vbi_data *data = vbi->data + idx;
11662306a36Sopenharmony_ci		unsigned start_2nd_field;
11762306a36Sopenharmony_ci		unsigned line = data->line;
11862306a36Sopenharmony_ci		u8 *linebuf = buf;
11962306a36Sopenharmony_ci
12062306a36Sopenharmony_ci		start_2nd_field = (data->id & V4L2_SLICED_VBI_525) ? 263 : 313;
12162306a36Sopenharmony_ci		if (data->field)
12262306a36Sopenharmony_ci			line += start_2nd_field;
12362306a36Sopenharmony_ci		line -= vbi_fmt->start[data->field];
12462306a36Sopenharmony_ci
12562306a36Sopenharmony_ci		if (vbi_fmt->flags & V4L2_VBI_INTERLACED)
12662306a36Sopenharmony_ci			linebuf += (line * 2 + data->field) *
12762306a36Sopenharmony_ci				vbi_fmt->samples_per_line;
12862306a36Sopenharmony_ci		else
12962306a36Sopenharmony_ci			linebuf += (line + data->field * vbi_fmt->count[0]) *
13062306a36Sopenharmony_ci				vbi_fmt->samples_per_line;
13162306a36Sopenharmony_ci		if (data->id == V4L2_SLICED_CAPTION_525)
13262306a36Sopenharmony_ci			vivid_vbi_gen_cc_raw(data, linebuf, vbi_fmt->sampling_rate);
13362306a36Sopenharmony_ci		else if (data->id == V4L2_SLICED_WSS_625)
13462306a36Sopenharmony_ci			vivid_vbi_gen_wss_raw(data, linebuf, vbi_fmt->sampling_rate);
13562306a36Sopenharmony_ci		else if (data->id == V4L2_SLICED_TELETEXT_B)
13662306a36Sopenharmony_ci			vivid_vbi_gen_teletext_raw(data, linebuf, vbi_fmt->sampling_rate);
13762306a36Sopenharmony_ci	}
13862306a36Sopenharmony_ci}
13962306a36Sopenharmony_ci
14062306a36Sopenharmony_cistatic const u8 vivid_cc_sequence1[30] = {
14162306a36Sopenharmony_ci	0x14, 0x20,	/* Resume Caption Loading */
14262306a36Sopenharmony_ci	'H',  'e',
14362306a36Sopenharmony_ci	'l',  'l',
14462306a36Sopenharmony_ci	'o',  ' ',
14562306a36Sopenharmony_ci	'w',  'o',
14662306a36Sopenharmony_ci	'r',  'l',
14762306a36Sopenharmony_ci	'd',  '!',
14862306a36Sopenharmony_ci	0x14, 0x2f,	/* End of Caption */
14962306a36Sopenharmony_ci};
15062306a36Sopenharmony_ci
15162306a36Sopenharmony_cistatic const u8 vivid_cc_sequence2[30] = {
15262306a36Sopenharmony_ci	0x14, 0x20,	/* Resume Caption Loading */
15362306a36Sopenharmony_ci	'C',  'l',
15462306a36Sopenharmony_ci	'o',  's',
15562306a36Sopenharmony_ci	'e',  'd',
15662306a36Sopenharmony_ci	' ',  'c',
15762306a36Sopenharmony_ci	'a',  'p',
15862306a36Sopenharmony_ci	't',  'i',
15962306a36Sopenharmony_ci	'o',  'n',
16062306a36Sopenharmony_ci	's',  ' ',
16162306a36Sopenharmony_ci	't',  'e',
16262306a36Sopenharmony_ci	's',  't',
16362306a36Sopenharmony_ci	0x14, 0x2f,	/* End of Caption */
16462306a36Sopenharmony_ci};
16562306a36Sopenharmony_ci
16662306a36Sopenharmony_cistatic u8 calc_parity(u8 val)
16762306a36Sopenharmony_ci{
16862306a36Sopenharmony_ci	unsigned i;
16962306a36Sopenharmony_ci	unsigned tot = 0;
17062306a36Sopenharmony_ci
17162306a36Sopenharmony_ci	for (i = 0; i < 7; i++)
17262306a36Sopenharmony_ci		tot += (val & (1 << i)) ? 1 : 0;
17362306a36Sopenharmony_ci	return val | ((tot & 1) ? 0 : 0x80);
17462306a36Sopenharmony_ci}
17562306a36Sopenharmony_ci
17662306a36Sopenharmony_cistatic void vivid_vbi_gen_set_time_of_day(u8 *packet)
17762306a36Sopenharmony_ci{
17862306a36Sopenharmony_ci	struct tm tm;
17962306a36Sopenharmony_ci	u8 checksum, i;
18062306a36Sopenharmony_ci
18162306a36Sopenharmony_ci	time64_to_tm(ktime_get_real_seconds(), 0, &tm);
18262306a36Sopenharmony_ci	packet[0] = calc_parity(0x07);
18362306a36Sopenharmony_ci	packet[1] = calc_parity(0x01);
18462306a36Sopenharmony_ci	packet[2] = calc_parity(0x40 | tm.tm_min);
18562306a36Sopenharmony_ci	packet[3] = calc_parity(0x40 | tm.tm_hour);
18662306a36Sopenharmony_ci	packet[4] = calc_parity(0x40 | tm.tm_mday);
18762306a36Sopenharmony_ci	if (tm.tm_mday == 1 && tm.tm_mon == 2 &&
18862306a36Sopenharmony_ci	    sys_tz.tz_minuteswest > tm.tm_min + tm.tm_hour * 60)
18962306a36Sopenharmony_ci		packet[4] = calc_parity(0x60 | tm.tm_mday);
19062306a36Sopenharmony_ci	packet[5] = calc_parity(0x40 | (1 + tm.tm_mon));
19162306a36Sopenharmony_ci	packet[6] = calc_parity(0x40 | (1 + tm.tm_wday));
19262306a36Sopenharmony_ci	packet[7] = calc_parity(0x40 | ((tm.tm_year - 90) & 0x3f));
19362306a36Sopenharmony_ci	packet[8] = calc_parity(0x0f);
19462306a36Sopenharmony_ci	for (checksum = i = 0; i <= 8; i++)
19562306a36Sopenharmony_ci		checksum += packet[i] & 0x7f;
19662306a36Sopenharmony_ci	packet[9] = calc_parity(0x100 - checksum);
19762306a36Sopenharmony_ci	packet[10] = calc_parity(0x07);
19862306a36Sopenharmony_ci	packet[11] = calc_parity(0x04);
19962306a36Sopenharmony_ci	if (sys_tz.tz_minuteswest >= 0)
20062306a36Sopenharmony_ci		packet[12] = calc_parity(0x40 | ((sys_tz.tz_minuteswest / 60) & 0x1f));
20162306a36Sopenharmony_ci	else
20262306a36Sopenharmony_ci		packet[12] = calc_parity(0x40 | ((24 + sys_tz.tz_minuteswest / 60) & 0x1f));
20362306a36Sopenharmony_ci	packet[13] = calc_parity(0);
20462306a36Sopenharmony_ci	packet[14] = calc_parity(0x0f);
20562306a36Sopenharmony_ci	for (checksum = 0, i = 10; i <= 14; i++)
20662306a36Sopenharmony_ci		checksum += packet[i] & 0x7f;
20762306a36Sopenharmony_ci	packet[15] = calc_parity(0x100 - checksum);
20862306a36Sopenharmony_ci}
20962306a36Sopenharmony_ci
21062306a36Sopenharmony_cistatic const u8 hamming[16] = {
21162306a36Sopenharmony_ci	0x15, 0x02, 0x49, 0x5e, 0x64, 0x73, 0x38, 0x2f,
21262306a36Sopenharmony_ci	0xd0, 0xc7, 0x8c, 0x9b, 0xa1, 0xb6, 0xfd, 0xea
21362306a36Sopenharmony_ci};
21462306a36Sopenharmony_ci
21562306a36Sopenharmony_cistatic void vivid_vbi_gen_teletext(u8 *packet, unsigned line, unsigned frame)
21662306a36Sopenharmony_ci{
21762306a36Sopenharmony_ci	unsigned offset = 2;
21862306a36Sopenharmony_ci	unsigned i;
21962306a36Sopenharmony_ci
22062306a36Sopenharmony_ci	packet[0] = hamming[1 + ((line & 1) << 3)];
22162306a36Sopenharmony_ci	packet[1] = hamming[line >> 1];
22262306a36Sopenharmony_ci	memset(packet + 2, 0x20, 40);
22362306a36Sopenharmony_ci	if (line == 0) {
22462306a36Sopenharmony_ci		/* subcode */
22562306a36Sopenharmony_ci		packet[2] = hamming[frame % 10];
22662306a36Sopenharmony_ci		packet[3] = hamming[frame / 10];
22762306a36Sopenharmony_ci		packet[4] = hamming[0];
22862306a36Sopenharmony_ci		packet[5] = hamming[0];
22962306a36Sopenharmony_ci		packet[6] = hamming[0];
23062306a36Sopenharmony_ci		packet[7] = hamming[0];
23162306a36Sopenharmony_ci		packet[8] = hamming[0];
23262306a36Sopenharmony_ci		packet[9] = hamming[1];
23362306a36Sopenharmony_ci		offset = 10;
23462306a36Sopenharmony_ci	}
23562306a36Sopenharmony_ci	packet += offset;
23662306a36Sopenharmony_ci	memcpy(packet, "Page: 100 Row: 10", 17);
23762306a36Sopenharmony_ci	packet[7] = '0' + frame / 10;
23862306a36Sopenharmony_ci	packet[8] = '0' + frame % 10;
23962306a36Sopenharmony_ci	packet[15] = '0' + line / 10;
24062306a36Sopenharmony_ci	packet[16] = '0' + line % 10;
24162306a36Sopenharmony_ci	for (i = 0; i < 42 - offset; i++)
24262306a36Sopenharmony_ci		packet[i] = calc_parity(packet[i]);
24362306a36Sopenharmony_ci}
24462306a36Sopenharmony_ci
24562306a36Sopenharmony_civoid vivid_vbi_gen_sliced(struct vivid_vbi_gen_data *vbi,
24662306a36Sopenharmony_ci		bool is_60hz, unsigned seqnr)
24762306a36Sopenharmony_ci{
24862306a36Sopenharmony_ci	struct v4l2_sliced_vbi_data *data0 = vbi->data;
24962306a36Sopenharmony_ci	struct v4l2_sliced_vbi_data *data1 = vbi->data + 1;
25062306a36Sopenharmony_ci	unsigned frame = seqnr % 60;
25162306a36Sopenharmony_ci
25262306a36Sopenharmony_ci	memset(vbi->data, 0, sizeof(vbi->data));
25362306a36Sopenharmony_ci
25462306a36Sopenharmony_ci	if (!is_60hz) {
25562306a36Sopenharmony_ci		unsigned i;
25662306a36Sopenharmony_ci
25762306a36Sopenharmony_ci		for (i = 0; i <= 11; i++) {
25862306a36Sopenharmony_ci			data0->id = V4L2_SLICED_TELETEXT_B;
25962306a36Sopenharmony_ci			data0->line = 7 + i;
26062306a36Sopenharmony_ci			vivid_vbi_gen_teletext(data0->data, i, frame);
26162306a36Sopenharmony_ci			data0++;
26262306a36Sopenharmony_ci		}
26362306a36Sopenharmony_ci		data0->id = V4L2_SLICED_WSS_625;
26462306a36Sopenharmony_ci		data0->line = 23;
26562306a36Sopenharmony_ci		/* 4x3 video aspect ratio */
26662306a36Sopenharmony_ci		data0->data[0] = 0x08;
26762306a36Sopenharmony_ci		data0++;
26862306a36Sopenharmony_ci		for (i = 0; i <= 11; i++) {
26962306a36Sopenharmony_ci			data0->id = V4L2_SLICED_TELETEXT_B;
27062306a36Sopenharmony_ci			data0->field = 1;
27162306a36Sopenharmony_ci			data0->line = 7 + i;
27262306a36Sopenharmony_ci			vivid_vbi_gen_teletext(data0->data, 12 + i, frame);
27362306a36Sopenharmony_ci			data0++;
27462306a36Sopenharmony_ci		}
27562306a36Sopenharmony_ci		return;
27662306a36Sopenharmony_ci	}
27762306a36Sopenharmony_ci
27862306a36Sopenharmony_ci	data0->id = V4L2_SLICED_CAPTION_525;
27962306a36Sopenharmony_ci	data0->line = 21;
28062306a36Sopenharmony_ci	data1->id = V4L2_SLICED_CAPTION_525;
28162306a36Sopenharmony_ci	data1->field = 1;
28262306a36Sopenharmony_ci	data1->line = 21;
28362306a36Sopenharmony_ci
28462306a36Sopenharmony_ci	if (frame < 15) {
28562306a36Sopenharmony_ci		data0->data[0] = calc_parity(vivid_cc_sequence1[2 * frame]);
28662306a36Sopenharmony_ci		data0->data[1] = calc_parity(vivid_cc_sequence1[2 * frame + 1]);
28762306a36Sopenharmony_ci	} else if (frame >= 30 && frame < 45) {
28862306a36Sopenharmony_ci		frame -= 30;
28962306a36Sopenharmony_ci		data0->data[0] = calc_parity(vivid_cc_sequence2[2 * frame]);
29062306a36Sopenharmony_ci		data0->data[1] = calc_parity(vivid_cc_sequence2[2 * frame + 1]);
29162306a36Sopenharmony_ci	} else {
29262306a36Sopenharmony_ci		data0->data[0] = calc_parity(0);
29362306a36Sopenharmony_ci		data0->data[1] = calc_parity(0);
29462306a36Sopenharmony_ci	}
29562306a36Sopenharmony_ci
29662306a36Sopenharmony_ci	frame = seqnr % (30 * 60);
29762306a36Sopenharmony_ci	switch (frame) {
29862306a36Sopenharmony_ci	case 0:
29962306a36Sopenharmony_ci		vivid_vbi_gen_set_time_of_day(vbi->time_of_day_packet);
30062306a36Sopenharmony_ci		fallthrough;
30162306a36Sopenharmony_ci	case 1 ... 7:
30262306a36Sopenharmony_ci		data1->data[0] = vbi->time_of_day_packet[frame * 2];
30362306a36Sopenharmony_ci		data1->data[1] = vbi->time_of_day_packet[frame * 2 + 1];
30462306a36Sopenharmony_ci		break;
30562306a36Sopenharmony_ci	default:
30662306a36Sopenharmony_ci		data1->data[0] = calc_parity(0);
30762306a36Sopenharmony_ci		data1->data[1] = calc_parity(0);
30862306a36Sopenharmony_ci		break;
30962306a36Sopenharmony_ci	}
31062306a36Sopenharmony_ci}
311